To see the other types of publications on this topic, follow the link: M-cels.
Journal articles on the topic 'M-cels'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'M-cels.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Mesquita, Hilda de Souza Lima, and Ana Júlia Fernandes. "Variação de curta escala temporal de bactérias, plcofltoplâncton e nanoheterótrofos na região de Ubatuba - SP, Brasil." Revista Brasileira de Oceanografia 44, no. 1 (1996): 47–56. http://dx.doi.org/10.1590/s1413-77391996000100005.
Full textAbstract:
A variação temporal da comunidade microbiana (bactérias, picofitoplâncton total e nanoheterótrofos) nas águas de Ubatuba (23°S 45°W) foi estudada durante um período de 7 dias (de 27/02 a 04/03/1988). As amostras foram obtidas na termoclina, duas vezes ao dia (na estôfa da maré baixa e da maré alta durante o período diurno. A densidade de nanoheterótrofos variou de 0,9 a 3,5 x 10³ cels m-1 apresentando valor médio de 2,3 x 10³ cels m-1. Picofitoplâncton total foi representado principalmente por cianobactérias cocóides e sua denside de variocões de 1,0 a 7,6 x 10(6) cels m-1. O número de bactérias variou de 1,0 a 2,7 x 10 cels m-l . A população bacteriana apresentou um padrão de oscilação defasado em relação a variação das concentrações de CI a. O intervalo de tempo entre os valores máximos de Cl a e as densidades máximas de bactéria foi de aproximadamente 24 horas. No início do período de estudo, a interrelação entre nanoheterótrofos e bactérias-picofitoplâncton foi caracterizada por uma oscilação inversa, sugerindo uma interação predador- presa. A partir do dia 02 de março as 3 populações variaram quase que em fase. As influências das condições meteorológicas, do movimento das marés e da predação por microzooplâncton e metazoários são discutidas. A despeito dos vários fatores que podem afetar as interrelações entre nanoheterótrofos e bactérias- picofitoplâncton parece que o padrão observado não é errático e pode estar expressando uma intensa atividade predatória.
2
Samper Prunera, Emili. "(Algunes) variacions sobre el diable: una proposta de catalogació de dues llegendes satàniques." Estudis de Literatura Oral Popular / Studies in Oral Folk Literature, no. 4 (December 17, 2015): 107. http://dx.doi.org/10.17345/elop2015107-120.
Full textAbstract:
En el marc del projecte «RondCat: rondalles catalanes», dirigit per Carme Oriol i Josep M. Pujol, i la catalogació de rondalles que no tenen correspondència a l’índex internacional d’Aarne-Thompson-Uther [ATU], es proposa la creació de dos tipus nous: C-103 («Dimoni, on vas?») i C-113 (La fondària del gorg). El punt de partida és l’estudi de la llegenda satànica fet per Josep M. Pujol l’any 1994 («Variacions sobre el diable»), així com el corpus recollit pel folklorista Cels Gomis i Mestre (1841-1915). La proposta de creació dels dos tipus inclou la relació de les versions catalanes localitzades fins al moment.
3
Magalhaes, Roberto J. Pessoa, María-Belén Vidriales, Bruno Paiva, Maria-Victoria Mateos, Norma C. Gutierrez, Ramón García-Sanz, Juan F. Blanco, et al. "Multidimensional Flow Cytometric (MFC) Analysis of the Immune System of Multiple Myeloma (MM) Patients Achieving Long Term Disease Control." Blood 118, no. 21 (November 18, 2011): 810. http://dx.doi.org/10.1182/blood.v118.21.810.810.
Full textAbstract:
Abstract Abstract 810FN2 Increasing evidence shows that a small fraction of MM patients (pts) treated with high-dose therapy followed by autologous stem cell transplantation achieve long-term remission. Interestingly, this is not restricted to pts in complete response (CR), since those that revert to a monoclonal gammopathy of undetermined significance (MGUS) profile may also achieve long-term remission, despite the persistence of residual myeloma plasma cells (PCs). These results suggest that in addition to the anti-myeloma therapy, other factors may play a role in the control of the disease. Herein, we used 8-color MFC for detailed characterization of the structural components of the immune system and hematopoietic precursor cells (HPC) in paired bone marrow (BM) and peripheral blood (PB) samples from 26 MM patients in long-term disease control (LTDC): 9 in continuous CR and 17 who reverted to an MGUS profile and that subsequently showed stable disease without treatment for ≥5 years (median of 9 years; range, 5–19). As controls, paired BM and PB samples from 23 newly-diagnosed MGUS and 16 MM pts, together with 10 healthy adults (HA), were studied in parallel. In all BM and PB samples the distribution of the major T- (CD4, CD8, Tregs and γδ), NK- (CD56dim and CD56bright) and B-cell subsets (Pro-B, Pre-B, naïve and memory), in addition to normal PCs, dendritic cell (DC) subsets (plasmacytoid, myeloid and monocytic), monocytes, and CD34+ HPC (myeloid and lymphoid), were studied. The percentage and absolute count of each cell population was analysed in the BM and PB, respectively. Comparison of the two groups of MM pts with LTDC (9 CR vs. 17 MGUS-like) showed similar (p>.05) cellular profiles in PB and BM, except for an increased number of BM and PB normal PCs in CR patients (P≤.04). Consequently, for all subsequent analyses, LTDC myeloma pts were pooled together. When compared to HA, patients with LTDC had increased numbers of CD8 T-cells and CD56dim NK-cells in both the BM and PB (p≤.03 and p≤.01, respectively). Despite this, the distribution of BM and PB CD4, CD8 and γδ T-cells among LTDC patients was similar (p>.05) to that of both newly-diagnosed MM and MGUS cases; in contrast, BM and PB Tregs were significantly decreased vs newly-diagnosed MM (P=.03) and MGUS (P=.04). Regarding B-cells and normal PCs, LTDC patients showed increased numbers of BM B-cell precursors (both Pro-B and Pre-B cells) and normal PCs vs. newly diagnosed MM (P≤.05), but not MGUS, together with increased numbers of naïve B-cells vs. both MM and MGUS pts (P≤.01); all such cell populations returned to levels similar (p>.05) to those of HA. As expected, this also included the number of CD34+ B-cell HPC which was increased among patients who achieved LTDC vs MM (p=.02), at levels similar (p>.05) to those of MGUS and HA. Regarding DC, LTDC patients showed normal DC numbers in PB (but with higher PB myeloid-DC numbers vs. MM; p=.02), in association with decreased numbers of plasmacytoid DC and increased monocytic-DC in the BM vs. HA (p≤.04). No differences were found for the numbers of BM and PB monocytes. In summary, here we investigated for the first time the immune cell profile of MM patients who achieve long-term disease control. Our results show that, as newly-diagnosed MM, patients that achieve long-term disease control also show increased numbers of cytotoxic T-cells and CD56dim NK-cells; however, in contrast to newly-diagnosed MM, among LTDC patients such increase is associated with lower numbers of T-regs and an almost complete recovery of the normal PC, B-cell precursor and naïve B-cell compartments both in BM and PB. Further investigations on the activation and functional status of these cell populations are warranted.MO (%)/SP (cels./μl)HA N= 10MGUS N= 23MM N= 16LTDC-MM N= 26T cells9.588110.6117313113711926 CD4+4.85004.6624^6*5085463 CD8+3.7∼216∼4.63865.32645.3431 TCR γδ.2426.3230.2428.3421 Treg.4137.4141^.54*38.3432NK cells.7∼87∼1.51982.11721.6212 CD56 dim.65∼79∼1.41922.21681.6202B cells2.81471.8104.97*68*1.9160 Pro B.11—.06—.02*—.07— Pre B.6—.4—.08—.23— Naive SP—80—57^—36*—118 Normal-PCS.18.9.11.7.008.72*.11.84DCs.3449.3653.6848.558 Monocytes2.22472.42853.43023.1315 m-DC SP—11—14—8*—12 MO-DC.11∼29.2036.434.2837 p-DC.2∼4.1.145.112.8.123.8CD34+.9∼1.46.61.1.261.4.431.4 Mie-HPC.8∼—.53—.26—.36— Linfo-HPC.1—.07—.03*—.05—*p≤.05 LTDC vs MM: ^ p≤.05 LTDC vs MGUS; ∼ p≤.05 LTDC vs HA Disclosures: Paiva: Jansen-Cillag: Honoraria; Celgene: Honoraria. Martinez:Janssen: Honoraria; Celgene: Honoraria. Maiolino:Centocor Ortho Biotech Research & Development: Research Funding.
4
Setlow, Jane K. "Genetics in Chinese Hamster Cells Molecular Cell Genetics M. M. Gottesman." BioScience 36, no. 10 (November 1986): 680–82. http://dx.doi.org/10.2307/1310394.
Full text
5
Kanaya, Takashi, Kohtaro Miyazawa, Ikuro Takakura, Wataru Itani, Kouichi Watanabe, Shyuichi Ohwada, Haruki Kitazawa, et al. "Differentiation of a murine intestinal epithelial cell line (MIE) toward the M cell lineage." American Journal of Physiology-Gastrointestinal and Liver Physiology 295, no. 2 (August 2008): G273—G284. http://dx.doi.org/10.1152/ajpgi.00378.2007.
Full textAbstract:
M cells are a kind of intestinal epithelial cell in the follicle-associated epithelium of Peyer's patches. These cells can transport antigens and microorganisms into underlying lymphoid tissues. Despite the important role of M cells in mucosal immune responses, the origin and mechanisms of differentiation as well as cell death of M cells remain unclear. To clarify the mechanism of M cell differentiation, we established a novel murine intestinal epithelial cell line (MIE) from the C57BL/6 mouse. MIE cells grow rapidly and have a cobblestone morphology, which is a typical feature of intestinal epithelial cells. Additionally, they express cytokeratin, villin, cell-cell junctional proteins, and alkaline phosphatase activity and can form microvilli. Their expression of Musashi-1 antigen indicates that they may be close to intestinal stem cells or transit-amplifying cells. MIE cells are able to differentiate into the M cell lineage following coculture with intestinal lymphocytes, but not with Peyer's patch lymphocytes (PPL). However, PPL costimulated with anti-CD3/CD28 MAbs caused MIE cells to display typical features of M cells, such as transcytosis activity, the disorganization of microvilli, and the expression of M cell markers. This transcytosis activity of MIE cells was not induced by T cells isolated from PPL costimulated with the same MAbs and was reduced by the depletion of the T cell population from PPL. A mixture of T cells treated with MAbs and B cells both from PPL led MIE cells to differentiate into M cells. We report here that MIE cells have the potential ability to differentiate into M cells and that this differentiation required activated T cells and B cells.
6
Uemura, N., K. Ozawa, K. Takahashi, A. Tojo, K. Tani, K. Harigaya, S. Suzu, K. Motoyoshi, H. Matsuda, and H. Yagita. "Binding of membrane-anchored macrophage colony-stimulating factor (M- CSF) to its receptor mediates specific adhesion between stromal cells and M-CSF receptor-bearing hematopoietic cells." Blood 82, no. 9 (November 1, 1993): 2634–40. http://dx.doi.org/10.1182/blood.v82.9.2634.2634.
Full textAbstract:
Abstract To explore the biologic significance of the membrane-anchored form of macrophage colony-stimulating factor (M-CSF), we examined whether interaction between membrane-bound M-CSF and its receptor mediates intercellular adhesion as well as cell proliferation and differentiation. Human M-CSF receptors were expressed on a murine interleukin-2 (IL-3)-dependent cell line, FDC-P2, by DNA transfection with the c-fms gene (FDC-P2-MCSFR). A human bone marrow-derived stromal cell line, KM102, was used in the cell adhesion assay. The expression of membrane-bound M-CSF on KM102 cells was demonstrated by flow cytometry and immunoblot analysis. After the incubation of parent and transformed FDC-P2 cells on confluent KM102 cells, nonadherent cells were removed and the cells attached to KM102 cells were examined microscopically. Almost all parent FDC-P2 cells were nonadherent, whereas a significant number of FDC-P2-MCSFR cells bound to KM102 cells. The addition of anti-M-CSF or anti-M-CSF receptor neutralizing antibodies dose-dependently inhibited the binding of [3H]-thymidine- labeled FDC-P2-MCSFR cells to KM102 cells. An excess amount of M-CSF also inhibited the binding. On the other hand, the addition of antibodies against some representative adhesion molecules (vitronectin receptor, Pgp-1/CD44, and VLA-4) did not inhibit the adhesion between FDC-P2-MCSFR cells and KM102 cells. These results support the idea that membrane-anchored M-CSF and its receptor may function as mediators of cell-cell adhesion.
7
Uemura, N., K. Ozawa, K. Takahashi, A. Tojo, K. Tani, K. Harigaya, S. Suzu, K. Motoyoshi, H. Matsuda, and H. Yagita. "Binding of membrane-anchored macrophage colony-stimulating factor (M- CSF) to its receptor mediates specific adhesion between stromal cells and M-CSF receptor-bearing hematopoietic cells." Blood 82, no. 9 (November 1, 1993): 2634–40. http://dx.doi.org/10.1182/blood.v82.9.2634.bloodjournal8292634.
Full textAbstract:
To explore the biologic significance of the membrane-anchored form of macrophage colony-stimulating factor (M-CSF), we examined whether interaction between membrane-bound M-CSF and its receptor mediates intercellular adhesion as well as cell proliferation and differentiation. Human M-CSF receptors were expressed on a murine interleukin-2 (IL-3)-dependent cell line, FDC-P2, by DNA transfection with the c-fms gene (FDC-P2-MCSFR). A human bone marrow-derived stromal cell line, KM102, was used in the cell adhesion assay. The expression of membrane-bound M-CSF on KM102 cells was demonstrated by flow cytometry and immunoblot analysis. After the incubation of parent and transformed FDC-P2 cells on confluent KM102 cells, nonadherent cells were removed and the cells attached to KM102 cells were examined microscopically. Almost all parent FDC-P2 cells were nonadherent, whereas a significant number of FDC-P2-MCSFR cells bound to KM102 cells. The addition of anti-M-CSF or anti-M-CSF receptor neutralizing antibodies dose-dependently inhibited the binding of [3H]-thymidine- labeled FDC-P2-MCSFR cells to KM102 cells. An excess amount of M-CSF also inhibited the binding. On the other hand, the addition of antibodies against some representative adhesion molecules (vitronectin receptor, Pgp-1/CD44, and VLA-4) did not inhibit the adhesion between FDC-P2-MCSFR cells and KM102 cells. These results support the idea that membrane-anchored M-CSF and its receptor may function as mediators of cell-cell adhesion.
8
Ebisawa, Masashi, Koji Hase, Daisuke Takahashi, Hiroshi Kitamura, Kathryn A. Knoop, Ifor R. Williams, and Hiroshi Ohno. "CCR6hiCD11cint B cells promote M-cell differentiation in Peyer's patch." International Immunology 23, no. 4 (March 21, 2011): 261–69. http://dx.doi.org/10.1093/intimm/dxq478.
Full text
9
Lelouard, Hugues, Alain Sahuquet, Hubert Reggio, and Philippe Montcourrier. "Rabbit M cells and dome enterocytes are distinct cell lineages." Journal of Cell Science 114, no. 11 (June 1, 2001): 2077–83. http://dx.doi.org/10.1242/jcs.114.11.2077.
Full textAbstract:
We have studied the M cell origin and differentiation pathway in rabbit gut-associated lymphoid tissues. Micro-dissected domes and epithelium isolated by ethylene diamine tetra acetic acid detachment allowed us to view the whole epithelial surface from the bottom of crypts to the top of domes. We used monoclonal antibodies specific to the apex of either M cells or dome enterocytes, lectins, and antibodies to vimentin in appendix, distal Peyer’s patches and caecal patches. The earliest vimentin-labeled M cells were observed in the BrdU-positive proliferative zone of dome-associated crypts. Gradual differentiation of the M cell vimentin cytoskeleton started at this site to progressively give rise to the first pocket-forming M cells in the upper dome. Therefore, these mitotic cells of the crypts appear as the direct precursors of M cells. In addition to an early appearance of M cell markers, a regular mosaic-like relative distribution of M cells and dome enterocytes was already detected in the vicinity of crypts, similar to that observed on the lateral surface of domes where functional M cells lie. This constant distribution implies that there is no trans-differentiation of enterocytes to M cells along the crypt-dome axis. Together, these observations provide very strong evidence in favor of an early commitment in crypts of M cell and enterocyte distinct lineages.
10
Klisuric, Ana, Benjamin Thierry, Ludivine Delon, Clive A. Prestidge, and Rachel J. Gibson. "Identifying human and murine M cells in vitro." Experimental Biology and Medicine 244, no. 7 (March 24, 2019): 554–64. http://dx.doi.org/10.1177/1535370219838674.
Full textAbstract:
M cells are an epithelial cell population found in the follicle-associated epithelium overlying gut-associated lymphoid tissues. They are specialized in the transcytosis of luminal antigens. Their transcytotic capacity and location in an immunocompetent environment has prompted the study of these cells as possible targets for oral drug delivery systems. Currently, the models most commonly used to study M cells are restricted to in vivo experiments conducted in mice, and in vitro studies conducted in models comprised either of primary epithelial cells or established cell lines of murine or human origin. In vitro models of the follicle-associated epithelium can be constructed in several ways. Small intestinal Lgr5+ stem cells can be cultured into a 3D organoid structure where M cells are induced with RANKL administration. Additionally, in vitro models containing an “M cell-like” population can be obtained through co-culturing intestinal epithelial cells with cells of lymphocytic origin to induce the M cell phenotype. The evaluation of the efficiency of the variations of these models and their relevance to the in vivo human system is hampered by the lack of a universal M cell marker. This issue has also hindered the advancement of M cell-specific targeting approaches aimed at improving the bioavailability of orally administered compounds. This critical review discusses the different approaches utilized in the literature to identify M cells, their efficiency, reliability and relevance, in the context of commonly used models of the follicle-associated epithelium. The outcome of this review is a clearly defined and universally recognized criteria for the assessment of the relevance of models of the follicle-associated models currently used. Impact statement The study of M cells, a specialized epithelial cell type found in the follicle-associated epithelium, is hampered by the lack of a universal M cell marker. As such, many studies lack reliable and universally recognized methods to identify M cells in their proposed models. As a result of this it is difficult to ascertain whether the effects observed are due to the presence of M cells or an unaccounted variable. The outcome of this review is the thorough evaluation of the many M cell markers that have been used in the literature thus far and a proposed criterion for the identification of M cells for future publications. This will hopefully lead to an improvement in the quality of future publications in this field.
11
Ohno, Hiroshi. "Intestinal M cells." Journal of Biochemistry 159, no. 2 (December 3, 2015): 151–60. http://dx.doi.org/10.1093/jb/mvv121.
Full text
12
ANTZELEVITCH, CHARLES, WATARU SHIMIZU, GAN-XIN YAN, SERGE SICOURI, JACQUES WEISSENBURGER, VLADISLAV V. NESTERENKO, ALEXANDER BURASHNIKOV, JOSE DIEGO, JEFEREY SAFFITZ, and GEORGE P. THOMAS. "The M Cell:." Journal of Cardiovascular Electrophysiology 10, no. 8 (August 1999): 1124–52. http://dx.doi.org/10.1111/j.1540-8167.1999.tb00287.x.
Full text
13
Antzelevitch, Charles. "The M Cell." Journal of Cardiovascular Pharmacology and Therapeutics 2, no. 1 (March 1997): 73–76. http://dx.doi.org/10.1177/107424849700200109.
Full text
14
George, Joel Johnson, Laura Martin-Diaz, Markus J. T. Ojanen, Rosa Gasa, Marko Pesu, and Keijo Viiri. "PRC2 Regulated Atoh8 Is a Regulator of Intestinal Microfold Cell (M Cell) Differentiation." International Journal of Molecular Sciences 22, no. 17 (August 28, 2021): 9355. http://dx.doi.org/10.3390/ijms22179355.
Full textAbstract:
Intestinal microfold cells (M cells) are a dynamic lineage of epithelial cells that initiate mucosal immunity in the intestine. They are responsible for the uptake and transcytosis of microorganisms, pathogens, and other antigens in the gastrointestinal tract. A mature M cell expresses a receptor Gp2 which binds to pathogens and aids in the uptake. Due to the rarity of these cells in the intestine, their development and differentiation remain yet to be fully understood. We recently demonstrated that polycomb repressive complex 2 (PRC2) is an epigenetic regulator of M cell development, and 12 novel transcription factors including Atoh8 were revealed to be regulated by the PRC2. Here, we show that Atoh8 acts as a regulator of M cell differentiation; the absence of Atoh8 led to a significant increase in the number of Gp2+ mature M cells and other M cell-associated markers such as Spi-B and Sox8. In vitro organoid analysis of RankL treated organoid showed an increase of mature marker GP2 expression and other M cell-associated markers. Atoh8 null mice showed an increase in transcytosis capacity of luminal antigens. An increase in M cell population has been previously reported to be detrimental to mucosal immunity because some pathogens like orally acquired prions have been able to exploit the transcytosis capacity of M cells to infect the host; mice with an increased population of M cells are also susceptible to Salmonella infections. Our study here demonstrates that PRC2 regulated Atoh8 is one of the factors that regulate the population density of intestinal M cell in the Peyer’s patch.
15
Reyes, Leticia, Maureen K. Davidson, Linda C. Thomas, and Jerry K. Davis. "Effects of Mycoplasma fermentansincognitus on Differentiation of THP-1 Cells." Infection and Immunity 67, no. 7 (July 1, 1999): 3188–92. http://dx.doi.org/10.1128/iai.67.7.3188-3192.1999.
Full textAbstract:
ABSTRACT Mycoplasma fermentans incognitus has been isolated from human tissue in patients both with and without AIDS who died of systemic infection. M. fermentans incognitus and other strains of M. fermentans have been associated with rheumatoid arthritis. While cell extracts of M. fermentansincognitus can induce changes in murine and human cells of the monocytic lineage, little is known about interactions of viable organisms with such cells. Because of the central role of macrophages in chronic inflammation, we examined the effects of M. fermentans incognitus on surface markers and functions of THP-1 cells, a well-characterized human monocytic cell line. This cell line has been used extensively in studies of macrophage differentiation, especially following exposure to phorbol esters. Changes in cell morphology, phagocytosis, rate of cell division, and selected surface markers were evaluated in cultures of THP-1 cells exposed to phorbol myristate acetate (PMA), M. fermentans incognitus, or both. As reported by other investigators, PMA induced THP-1 cells to differentiate into cells resembling tissue macrophages. M. fermentans incognitus only minimally affected changes induced by PMA, slightly increasing the percentage of cells positive for FCγRI and major histocompatibility complex (MHC) class II antigens. M. fermentans incognitus alone induced an incomplete arrest in the cell cycle at G0 phase, increased phagocytic ability, and enhanced expression of FCγRI, CR3, CR4, and MHC class II antigens.
16
Clark, M. Ann, Barry H. Hirst, and Mark A. Jepson. "M-Cell Surface β1 Integrin Expression and Invasin-Mediated Targeting of Yersinia pseudotuberculosis to Mouse Peyer’s Patch M Cells." Infection and Immunity 66, no. 3 (March 1, 1998): 1237–43. http://dx.doi.org/10.1128/iai.66.3.1237-1243.1998.
Full textAbstract:
ABSTRACT Quantitative analysis of Yersinia pseudotuberculosisinfection of murine gut loops revealed that significantly more wild-type bacteria associated with Peyer’s patch M cells than with dome enterocytes or goblet cells. An invasin-deficient mutant was significantly attenuated for M-cell invasion, while β1 integrin expression was demonstrated in the apical membranes of M cells but not enterocytes. M-cell targeting by Yersinia pseudotuberculosis in vivo may, therefore, be mediated primarily by the interaction of invasin with cell surface β1 integrins.
17
Kitahashi, Takashi, Satoshi Ogawa, Tomoko Soga, Yasuo Sakuma, and Ishwar Parhar. "Sexual Maturation Modulates Expression of Nuclear Receptor Types in Laser-Captured Single Cells of the Cichlid (Oreochromis niloticus) Pituitary." Endocrinology 148, no. 12 (December 1, 2007): 5822–30. http://dx.doi.org/10.1210/en.2007-0311.
Full textAbstract:
The role of steroid/thyroid hormones in the regulation of endocrine cells at the level of the pituitary has remained unclear. Therefore, using single-cell quantitative real-time PCR, we examined absolute amounts of transcripts for nuclear receptors [estrogen receptors (ERs) α, β, and γ; androgen receptors (ARs) a and b; glucocorticoid receptors (GRs) 1, 2a, and 2b; and thyroid hormone receptors (TRs) α1, α2, and β] in pituitary cells of immature (IM) and mature (M) male tilapia, Oreochromis niloticus. In the two reproductive stages, ACTH cells expressed only ERβ, whereas all other pituitary cell types expressed ERα + β, and a subpopulation coexpressed ARa, ARb, GR1, GR2b, and TRβ but lacked ERγ, GR2a, TRα1, and TRα2. IM males had high percentages of LH cells (IM 46.0% vs. M 10.0%), GH cells (IM 23.3% vs. M 7.9%), and prolactin cells (IM 68.8% vs. M 6.0%) with ERβ, and TSH cells (IM 19.2% vs. M 0.0%) and MSH cells (IM 25.6% vs. M 0.0%) with ERα + TRβ. A high percentage of FSH cells in IM males expressed ERβ (IM 46.9% vs. M 18.8%), and FSH cells in M males showed significantly high GR1 transcripts (IM 76.0 ± 5.0 vs. M 195.0 ± 10.7 copies per cell; P < 0.05), suggesting that FSH cells are regulated differently in the two reproductive stages. Coexpression of ERα + β in high percentages of cells of the GH family (GH, IM 43.8% vs. M 14.3%; prolactin, IM 8.3% vs. M 59.7%; somatolactin, IM 22.2% vs. M 42.2%) suggests that the expression of both ERs is important for functionality. Thus, differential coexpression of genes for nuclear receptors in subpopulations of pituitary cell types suggests multiple steroid/thyroid hormone regulatory pathways at the level of the pituitary during the two reproductive stages.
18
Gebert, A. "M-cells in the rabbit tonsil exhibit distinctive glycoconjugates in their apical membranes." Journal of Histochemistry & Cytochemistry 44, no. 9 (September 1996): 1033–42. http://dx.doi.org/10.1177/44.9.8773569.
Full textAbstract:
The tonsil crypt epithelium contains membranous (M)-cells that transport antigens from the lumen to underlying lymphoid cells, thereby initiating specific immune responses. Mechanisms mediating the adhesion of antigens to the M-cell surface are important for effective and selective uptake of potential pathogens but are still poorly understood. Therefore, the carbohydrates present on crypt epithelial cells of the rabbit palatine tonsil were studied by lectin histochemistry. Ultrathin LR White sections were incubated with a panel of eight lectins conjugated to colloidal gold or biotin. The glycocalyx of the apical membrane of M-cells was selectively labeled by UEA-I, LTA, HPA, and VVA, whereas that of the remaining squamous epithelial cells preferentially bound RCA-I and PNA. WGA and ConA showed only little binding, with no discernible preference for any of the cell types. Double labeling of UEA-1 together with anti-vimentin antibodies revealed that UEA-I-positive epithelial cells also contained the rabbit M-cell marker vimentin, and vice versa. The results show that a specific composition of glycoconjugates, which differs from that on squamous epithelial cells, is found on M-cells of the rabbit tonsil. The M-cell-specific glycoproteins and glycolipids could be selectively targeted by microorganisms that adhere to M-cells and enter the host along this pathway.
19
Korbmacher, C., A. S. Segal, G. Fejes-Tóth, G. Giebisch, and E. L. Boulpaep. "Whole-cell currents in single and confluent M-1 mouse cortical collecting duct cells." Journal of General Physiology 102, no. 4 (October 1, 1993): 761–93. http://dx.doi.org/10.1085/jgp.102.4.761.
Full textAbstract:
M-1 cells, derived from a microdissected cortical collecting duct of a transgenic mouse, grown to confluence on a permeable support, develop a lumen-negative amiloride-sensitive transepithelial potential, reabsorb sodium, and secrete potassium. Electron micrographs show morphological features typical of principal cells in vivo. Using the patch clamp technique distinct differences are detected in whole-cell membrane current and voltage (Vm) between single M-1 cells 24 h after seeding vs cells grown to confluence. (a) Under control conditions (pipette: KCl-Ringer; bath: NaCl-Ringer) Vm averages -42.7 +/- 3.4 mV in single cells vs -16.8 +/- 4.1 mV in confluent cells. Whole-cell conductance (Gcell) in confluent cells is 2.6 times higher than in single cells. Cell capacitance values are not significantly different in single vs confluent M-1 cells, arguing against electrical coupling of confluent M-1 cells. (b) In confluent cells, 10(-4)-10(-5) M amiloride hyperpolarizes Vm to -39.7 +/- 3.0 mV and the amiloride-sensitive fractional conductance of 0.31 shows a sodium to potassium selectivity ratio of approximately 15. In contrast, single cells express no significant amiloride-sensitive conductance. (c) In single M-1 cells, Gcell is dominated by an inwardly rectifying K-conductance, as exposure to high bath K causes a large depolarization and doubling of Gcell. The barium-sensitive fraction of Gcell in symmetrical KCl-Ringer is 0.49 and voltage dependent. (d) In contrast, neither high K nor barium in the apical bath affect confluent M-1 cells, showing that confluent cells lack a significant apical K conductance. (e) Application of 500 microM glibenclamide reduces whole-cell currents in both single and confluent M-1 cells with a glibenclamide-sensitive fractional conductance of 0.71 and 0.83 in single and confluent cells, respectively. Glibenclamide inhibition occurs slower in confluent M-1 cells than in single cells, suggesting a basolateral action of this lipophilic drug on ATP-sensitive basolateral K channels in M-1 cells. (f) A component of the whole-cell conductance in M-1 cells appears as a deactivating outward current during large depolarizing voltage pulses and is abolished by extracellular chloride removal. The deactivating chloride current averages 103.6 +/- 16.1 pA/cell, comprises 24% of the outward current, and decays with a time constant of 179 +/- 13 ms. The outward to inward conductance ratio obtained from deactivating currents and tail currents is 2.4, indicating an outwardly rectifying chloride conductance.
20
Clark, M. A., M. A. Jepson, N. L. Simmons, T. A. Booth, and B. H. Hirst. "Differential expression of lectin-binding sites defines mouse intestinal M-cells." Journal of Histochemistry & Cytochemistry 41, no. 11 (November 1993): 1679–87. http://dx.doi.org/10.1177/41.11.7691933.
Full textAbstract:
We investigated the binding of four lectins to the follicle-associated epithelium (FAE) overlying fixed mouse small intestinal Peyer's patches to identify M-cell-specific surface markers. Wheat germ agglutinin and peanut agglutinin displayed heterogeneous staining patterns, binding most avidly to the intestine goblet cells. In contrast, the lectins Ulex europaeus 1 (UEA 1) and Psophocarpus tetragonolobus (winged bean; WBA) were almost exclusively M-cell specific. When confocal laser scanning images of tissues stained with fluorescein isothiocyanate (FITC)-conjugated UEA1 or WBA were compared with the appearance of the same tissues under the scanning electron microscope (SEM), UEA1 strongly stained 97.2% (106/109) of M-cells, 0.6% (3/516) enterocytes, and 0% (0/28) goblet cells, whereas WBA stained 100% (83/83) M-cells, 1.7% (6/361) enterocytes, and 5.3% (1/19) goblet cells. The M-cell specificity of the lectin binding was further demonstrated by localization of horseradish peroxidase (HRP)-conjugated lectins under the transmission electron microscope (TEM). This is the first demonstration of carbohydrates in the glycocalyx of M-cells that are not expressed elsewhere on the FAE surface. These carbohydrates not only provide a means to identify mouse M-cells by LM but may also contribute to the occurrence of specific interactions between microorganisms and the M-cell apical membrane.
21
Lee, Jinhee, Keumhwa Choi, Michael R. Olin, Sang-Nae Cho, and Thomas W. Molitor. "γδ T Cells in Immunity Induced by Mycobacterium bovis Bacillus Calmette-Guérin Vaccination." Infection and Immunity 72, no. 3 (March 2004): 1504–11. http://dx.doi.org/10.1128/iai.72.3.1504-1511.2004.
Full textAbstract:
ABSTRACT Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccination is efficacious for newborns or adults with no previous exposure to environmental mycobacteria. To determine the relative contribution and the nature of γδ T-cell receptor-positive T cells in newborns, compared to CD4+ T cells, in immunity induced by M. bovis BCG vaccination, 4-week-old specific-pathogen-free pigs were vaccinated with M. bovis BCG and monitored by following the γδ T-cell immune responses. A flow cytometry-based proliferation assay and intracellular staining for gamma interferon (IFN-γ) were used to examine γδ T-cell responses. Pigs were found to mount Th1-like responses to M. bovis BCG vaccination as determined by immunoproliferation and IFN-γ production. The γδ T-cell lymphoproliferation and IFN-γ production to stimulation with mycobacterial antigens were significantly enhanced by M. bovis BCG vaccination. The relative number of proliferating γδ T cells after stimulating peripheral blood mononuclear cells with Mycobacterium tuberculosis H37Rv culture filtrate protein was higher than that of CD4+ T cells at an early time point after M. bovis BCG vaccination, but CD4+ T cells were found to be more abundant at a later time point. Although the γδ T-cell responses were dependent on the presence of CD4+ T cells for the cytokine interleukin-2, the enhanced γδ T cells were due to the intrinsic changes of γδ T cells caused by M. bovis BCG vaccination rather than being due solely to help from CD4+ T cells. Our study shows that γδ T cells from pigs at early ages are functionally enhanced by M. bovis BCG vaccination and suggests an important role for this T-cell subset in acquired immunity conferred by M. bovis BCG vaccination.
22
Jensen, V. Behrana, John T. Harty, and Bradley D. Jones. "Interactions of the Invasive PathogensSalmonella typhimurium, Listeria monocytogenes, and Shigella flexneri with M Cells and Murine Peyer’s Patches." Infection and Immunity 66, no. 8 (August 1, 1998): 3758–66. http://dx.doi.org/10.1128/iai.66.8.3758-3766.1998.
Full textAbstract:
ABSTRACT Invasive enteric bacteria must pass through the intestinal epithelium in order to establish infection. It is becoming clear that a common target for intestinal mucosa penetration is the specialized epithelial cell of Peyer’s patches, the M cell. In order to gain a better understanding of how bacteria interact with M cells, we have compared the interactions of Salmonella typhimurium,Listeria monocytogenes, and Shigella flexneriwith M cells by using a murine ligated-loop model. Our results indicate that S. typhimurium possesses a highly efficient mechanism for M cell entry that targets and destroys these cells, while L. monocytogenes and S. flexneri appear to be internalized into M cells in a less disruptive fashion. Early uptake ofListeria or Shigella into M cells appeared to lead to the death of some cells, as evidenced by the appearance of holes in the intestinal epithelium. At later time points, the follicle-associated epithelium of animals infected with these bacteria displayed extensive destruction. These data indicate that enteric pathogens use different strategies to interact with M cells and initiate infection of a host.
23
Kanaya, Takashi, Sayuri Sakakibara, Toshi Jinnohara, Masami Hachisuka, Naoko Tachibana, Shinya Hidano, Takashi Kobayashi, et al. "Development of intestinal M cells and follicle-associated epithelium is regulated by TRAF6-mediated NF-κB signaling." Journal of Experimental Medicine 215, no. 2 (January 16, 2018): 501–19. http://dx.doi.org/10.1084/jem.20160659.
Full textAbstract:
M cells are located in the follicle-associated epithelium (FAE) that covers Peyer’s patches (PPs) and are responsible for the uptake of intestinal antigens. The differentiation of M cells is initiated by receptor activator of NF-κB. However, the intracellular pathways involved in M cell differentiation are still elusive. In this study, we demonstrate that the NF-κB pathway activated by RANK is essential for M cell differentiation using in vitro organoid culture. Overexpression of NF-κB transcription factors enhances the expression of M cell–associated molecules but is not sufficient to complete M cell differentiation. Furthermore, we evaluated the requirement for tumor necrosis factor receptor–associated factor 6 (TRAF6). Conditional deletion of TRAF6 in the intestinal epithelium causes a complete loss of M cells in PPs, resulting in impaired antigen uptake into PPs. In addition, the expression of FAE-associated genes is almost silenced in TRAF6-deficient mice. This study thus demonstrates the crucial role of TRAF6-mediated NF-κB signaling in the development of M cells and FAE.
24
Larabi, Anaïs, Laurène Salesse, Charlotte Cordonnier, Lucie Etienne-Mesmin, Nicolas Barnich, Guillaume Dalmasso, and Hang Thi Thu Nguyen. "Differential miRNA-Gene Expression in M Cells in Response to Crohn’s Disease-Associated AIEC." Microorganisms 8, no. 8 (August 7, 2020): 1205. http://dx.doi.org/10.3390/microorganisms8081205.
Full textAbstract:
Adherent-invasive Escherichia coli (AIEC), which abnormally colonize the ileal mucosa of Crohn’s disease (CD) patients, are able to invade intestinal epithelial cells (IECs) and translocate through M cells overlying Peyer’s patches. The levels of microRNA (miRNA) and gene expression in IECs and M cells upon AIEC infection have not been investigated. Here, we used human intestinal epithelial Caco-2 monolayers and an in vitro M-cell model of AIEC translocation to analyze comprehensive miRNA and gene profiling under basal condition and upon infection with the reference AIEC LF82 strain. Our results showed that AIEC LF82 translocated through M cells but not Caco-2 monolayers. Both differential gene expression and miRNA profile in M cells compared to Caco-2 cells were obtained. In addition, AIEC infection induces changes in gene and miRNA profiles in both Caco-2 and M cells. In silico analysis showed that certain genes dysregulated upon AIEC infection were potential targets of AIEC-dysregulated miRNAs, suggesting a miRNA-mediated regulation of gene expression during AIEC infection in Caco-2, as well as M cells. This study facilitates the discovery of M cell-specific and AIEC response-specific gene-miRNA signature and enhances the molecular understanding of M cell biology under basal condition and in response to infection with CD-associated AIEC.
25
Helander, Anna, Katherine J. Silvey, Nicholas J. Mantis, Amy B. Hutchings, Kartik Chandran, William T. Lucas, Max L. Nibert, and Marian R. Neutra. "The Viral σ1 Protein and Glycoconjugates Containing α2-3-Linked Sialic Acid Are Involved in Type 1 Reovirus Adherence to M Cell Apical Surfaces." Journal of Virology 77, no. 14 (July 15, 2003): 7964–77. http://dx.doi.org/10.1128/jvi.77.14.7964-7977.2003.
Full textAbstract:
ABSTRACT Type 1 reoviruses invade the intestinal mucosa of mice by adhering selectively to M cells in the follicle-associated epithelium and then exploiting M cell transport activity. The purpose of this study was to identify the apical cell membrane component and viral protein that mediate the M cell adherence of these viruses. Virions and infectious subviral particles of reovirus type 1 Lang (T1L) adhered to rabbit M cells in Peyer's patch mucosal explants and to tissue sections in an overlay assay. Viral adherence was abolished by pretreatment of sections with periodate and in the presence of excess sialic acid or lectins MAL-I and MAL-II (which recognize complex oligosaccharides containing sialic acid linked α2-3 to galactose). The binding of T1L particles to polarized human intestinal (Caco-2BBe) cell monolayers was correlated with the presence of MAL-I and MAL-II binding sites, blocked by excess MAL-I and -II, and abolished by neuraminidase treatment. Other type 1 reovirus isolates exhibited MAL-II-sensitive binding to rabbit M cells and polarized Caco-2BBe cells, but type 2 or type 3 isolates including type 3 Dearing (T3D) did not. In assays using T1L-T3D reassortants and recoated viral cores containing T1L, T3D, or no σ1 protein, MAL-II-sensitive binding to rabbit M cells and polarized Caco-2BBe cells was consistently associated with the T1L σ1. MAL-II-recognized oligosaccharide epitopes are not restricted to M cells in vivo, but MAL-II immobilized on virus-sized microparticles bound only to the follicle-associated epithelium and M cells. The results suggest that selective binding of type 1 reoviruses to M cells in vivo involves interaction of the type 1 σ1 protein with glycoconjugates containing α2-3-linked sialic acid that are accessible to viral particles only on M cell apical surfaces.
26
Dale, J. B., and E. H. Beachey. "Human cytotoxic T lymphocytes evoked by group A streptococcal M proteins." Journal of Experimental Medicine 166, no. 6 (December 1, 1987): 1825–35. http://dx.doi.org/10.1084/jem.166.6.1825.
Full textAbstract:
Purified group A streptococcal M proteins were used to stimulate peripheral blood lymphocytes from normal adult volunteers. The activated lymphocytes were cytotoxic against cultured human heart cells, as well as liver cells, fibroblasts, and K562 cells, but showed only minimal cytotoxicity against several animal cell types. The cytotoxic activity evoked by type 5 M protein was dose and time dependent. Rabbit antisera against pep M5 that contained heart-crossreactive antibodies partially inhibited cytotoxicity against heart cells, but had no effect on other target cells, suggesting that a fraction of the effector lymphocytes may be recognizing M protein-crossreactive cell surface antigens. All of the cytotoxic activity was recovered from a CD3+ population of lymphocytes obtained from a fluorescence-activated cell sorter, and CD4+ and CD8+ cells were also cytotoxic. M protein-responsive T cell clones were generated that showed specificity for heart and K562 cells, in addition to clones that were cytotoxic against both cell lines. Our data show that streptococcal M protein evokes cytotoxic T lymphocytes against multiple human but not animal target cells. Some of the effector cells may be specific for cultured myocardial cells, but their role in the pathogenesis of rheumatic carditis will require further studies of lymphocytes from patients with acute rheumatic fever and carditis.
27
Brzostek, Joanna, Amierah Fatin, Wen Hui Chua, Hui Yi Tan, Thomas Dick, and Nicholas R. J. Gascoigne. "Single Cell Analysis of Drug Susceptibility of Mycobacterium abscessus during Macrophage Infection." Antibiotics 9, no. 10 (October 17, 2020): 711. http://dx.doi.org/10.3390/antibiotics9100711.
Full textAbstract:
Mycobacterium abscessus is an emerging health risk to immunocompromised individuals and to people with pre-existing pulmonary conditions. As M. abscessus possesses multiple mechanisms of drug resistance, treatments of M. abscessus are of poor efficacy. Therefore, there is an urgent need for new therapeutic strategies targeting M. abscessus. We describe an experimental system for screening of compounds for their antimicrobial activity against intracellular M. abscessus using flow cytometry and imaging flow cytometry. The assay allows simultaneous analysis of multiple parameters, such as proportion of infected host cells, bacterial load per host cell from the infected population, and host cell viability. We verified the suitability of this method using two antibiotics with known activity against M. abscessus: clarithromycin and amikacin. Our analysis revealed a high degree of infection heterogeneity, which correlated with host cell size. A higher proportion of the larger host cells is infected with M. abscessus as compared to smaller host cells, and infected larger cells have higher intracellular bacterial burden than infected smaller cells. Clarithromycin treatment has a more pronounced effect on smaller host cells than on bigger host cells, suggesting that heterogeneity within the host cell population has an effect on antibiotic susceptibility of intracellular bacteria.
28
Schimpel, Christa, Oliver Werzer, Eleonore Fröhlich, Gerd Leitinger, Markus Absenger-Novak, Birgit Teubl, Andreas Zimmer, and Eva Roblegg. "Atomic force microscopy as analytical tool to study physico-mechanical properties of intestinal cells." Beilstein Journal of Nanotechnology 6 (July 6, 2015): 1457–66. http://dx.doi.org/10.3762/bjnano.6.151.
Full textAbstract:
The small intestine is a complex system that carries out various functions. The main function of enterocytes is absorption of nutrients, whereas membranous cells (M cells) are responsible for delivering antigens/foreign substances to the mucosal lymphoid tissues. However, to get a fundamental understanding of how cellular structures contribute to physiological processes, precise knowledge about surface morphologies, cytoskeleton organizations and biomechanical properties is necessary. Atomic force microscopy (AFM) was used here as a powerful tool to study surface topographies of Caco-2 cells and M cells. Furthermore, cell elasticity (i.e., the mechanical response of a cell on a tip indentation), was elucidated by force curve measurements. Besides elasticity, adhesion was evaluated by recording the attraction and repulsion forces between the tip and the cell surface. Organization of F-actin networks were investigated via phalloidin labeling and visualization was performed with confocal laser scanning fluorescence microscopy (CLSM) and scanning electron microscopy (SEM). The results of these various experimental techniques revealed significant differences in the cytoskeleton/microvilli arrangements and F-actin organization. Caco-2 cells displayed densely packed F-actin bundles covering the entire cell surface, indicating the formation of a well-differentiated brush border. In contrast, in M cells actins were arranged as short and/or truncated thin villi, only available at the cell edge. The elasticity of M cells was 1.7-fold higher compared to Caco-2 cells and increased significantly from the cell periphery to the nuclear region. Since elasticity can be directly linked to cell adhesion, M cells showed higher adhesion forces than Caco-2 cells. The combination of distinct experimental techniques shows that morphological differences between Caco-2 cells and M cells correlate with mechanical cell properties and provide useful information to understand physiological processes/mechanisms in the small intestine.
29
Chiou, Pinwen P., Carol H. Kim, Patricia Ormonde, and Jo-Ann C. Leong. "Infectious Hematopoietic Necrosis Virus Matrix Protein Inhibits Host-Directed Gene Expression and Induces Morphological Changes of Apoptosis in Cell Cultures." Journal of Virology 74, no. 16 (August 15, 2000): 7619–27. http://dx.doi.org/10.1128/jvi.74.16.7619-7627.2000.
Full textAbstract:
ABSTRACT Infectious hematopoietic necrosis virus (IHNV) infection in tissue culture cells has previously been shown to result in the shutdown of host protein synthesis, cell rounding, and cell death. We report here an investigation of the cytopathogenicity of the viral phosphoprotein (P or M1), matrix (M or M2), and nonvirion (NV) proteins in cultured fish cells. The expression of M alone potently inhibited reporter gene expression from a viral and an interferon (IFN)-inducible promoter, whereas P and NV did not produce a similar effect. Northern blot analysis further revealed a reduction in the steady-state level of reporter mRNA when the M gene was cotransfected into cells; conversely, M mRNA was not drastically reduced in the same cells. By immunofluorescence confocal microscopy, fragmented nuclei were found in some cells expressing M protein but not in cells expressing P, NV, or β-galactosidase protein. Electron microscopy revealed the morphological changes associated with apoptosis in the M-transfected cells. Furthermore, IHNV infection was shown to produce DNA “laddering” in cultured cells. Taken together, these data suggested at least two functions for M protein in an IHNV infection: down regulation of host transcription and the induction of programmed cell death. In the course of these experiments, we also discovered that NV expression was associated with cell rounding, the first biological effect on cells to be attributed to the NV gene.
30
Schmitz, Marc, Senming Zhao, Yvonne Deuse, Knut Schaekel, Martin Bornhaeuser, and Peter Rieber. "Tumoricidal Potential of Native Human Blood Dendritic Cells: Direct Tumor Cell Killing and Activation of NK Cell-Mediated Cytotoxicity." Blood 104, no. 11 (November 16, 2004): 449. http://dx.doi.org/10.1182/blood.v104.11.449.449.
Full textAbstract:
Abstract Dendritic cells (DCs) are characterized by their unique capacity for primary T cell activation, providing the opportunity of DC-based cancer vaccination protocols. Recently, we defined a novel major subset of human blood DCs by using the monoclonal antibody M-DC8 which recognizes a carbohydrate modification of P selectin glycoprotein ligand-1 (PSGL-1) selectively expressed on these cells (Immunity2002;17:289-301). In addition to a marked capacity to activate tumor-reactive cytotoxic T cells M-DC8+ DCs efficiently mediate antibody-dependent cytotoxicity (Blood;2002;100:1502-1504). In the present study, we analyzed the capacity of M-DC8+ DCs to kill tumor cells in the absence of antibodies and to enhance the tumor-directed cytotoxicity of NK cells. To determine whether M-DC8+ DCs exhibit tumoricidal activity, DCs were isolated at high purity (>93%) from the blood of healthy donors by immunomagnetic separation. These cells were cultured for 6 h in the presence or absence of 200 U/ml interferon (IFN)-gamma. Subsequently, DCs were coincubated with four chromium-labeled tumor cell lines and two normal cell lines for 18 h. Whereas unstimulated DCs demonstrated only moderate tumor-directed cytotoxicity (specific lysis: 7–13%), IFN-gamma-stimulated M-DC8+ DCs displayed potent killing of each of these tumor cell lines (specific lysis: 27–35%). Only a marginal cytotoxic effect was seen when normal human cells such as lung fibroblasts or endothelial cells were used as targets. When evaluating the cytotoxic effector mechanisms FACS analysis and ELISA assays revealed that IFN-gamma-stimulated M-DC8+ DCs secreted a high amount of tumor necrosis factor (TNF)-alpha induced by direct cell-to-cell contact with the different tumor cell lines. This effect was already observed after 3 h of cocultivation. Interestingly, no significant induction of TNF-alpha was detected during contact of M-DC8+ DCs with the normal human cell lines. These results suggest that tumor-associated surface molecules are important for the observed increase of TNF-alpha production in M-DC8+ DCs. Inhibition experiments with neutralizing antibodies clearly demonstrated that tumor cell-induced TNF-alpha play an important role in tumor-directed cytotoxicity mediated by M-DC8+ DCs. To investigate whether M-DC8+ DCs enhance the tumoricidal activity of NK cells freshly isolated DCs were cultured for 6 h in the presence or absence of IFN-gamma. Thereafter, DCs were coincubated with highly enriched (>90%) NK cells. The cytotoxic potential of the stimulated NK cells was tested towards various tumor cell lines in a 4 h chromium release assay. We observed a two- to threefold increase of NK cell-mediated cytotoxicity towards all analyzed tumor cell lines by IFN-gamma-stimulated M-DC8+ DCs. In addition, transwell experiments demonstrated that this triggering effect was mainly dependent on cell-to-cell contact. In conclusion, our data provide evidence that a major subpopulation of circulating human blood DCs exhibits efficient tumoricidal activity and clearly enhances NK cell-mediated tumor-directed cytotoxicity. The capacity of DCs to induce tumor-specific T cell responses and to kill tumor cells either directly or by activating NK cells points to the pivotal role of DCs in triggering the innate and adaptive immune response against tumors.
31
Wood, Megan B., Daniel Rios, and Ifor R. Williams. "TNF-α augments RANKL-dependent intestinal M cell differentiation in enteroid cultures." American Journal of Physiology-Cell Physiology 311, no. 3 (September 1, 2016): C498—C507. http://dx.doi.org/10.1152/ajpcell.00108.2016.
Full textAbstract:
Microfold (M) cells are phagocytic intestinal epithelial cells in the follicle-associated epithelium of Peyer's patches that transport particulate antigens from the gut lumen into the subepithelial dome. Differentiation of M cells from epithelial stem cells in intestinal crypts requires the cytokine receptor activator of NF-κB ligand (RANKL) and the transcription factor Spi-B. We used three-dimensional enteroid cultures established with small intestinal crypts from mice as a model system to investigate signaling pathways involved in M cell differentiation and the influence of other cytokines on RANKL-induced M cell differentiation. Addition of RANKL to enteroids induced expression of multiple M cell-associated genes, including Spib, Ccl9 [chemokine (C-C motif) ligand 9], Tnfaip2 (TNF-α-induced protein 2), Anxa5 (annexin A5), and Marcksl1 (myristoylated alanine-rich protein kinase C substrate) in 1 day. The mature M cell marker glycoprotein 2 ( Gp2) was strongly induced by 3 days and expressed by 11% of cells in enteroids. The noncanonical NF-κB pathway was required for RANKL-induced M cell differentiation in enteroids, as addition of RANKL to enteroids from mice with a null mutation in the mitogen-activated protein kinase kinase kinase 14 ( Map3k14) gene encoding NF-κB-inducing kinase failed to induce M cell-associated genes. While the cytokine TNF-α alone had little, if any, effect on expression of M cell-associated genes, addition of TNF-α to RANKL consistently resulted in three- to sixfold higher levels of multiple M cell-associated genes than RANKL alone. One contributing mechanism is the rapid induction by TNF-α of Relb and Nfkb2 (NF-κB subunit 2), genes encoding the two subunits of the noncanonical NF-κB heterodimer. We conclude that endogenous activators of canonical NF-κB signaling present in the gut-associated lymphoid tissue microenvironment, including TNF-α, can play a supportive role in the RANKL-dependent differentiation of M cells in the follicle-associated epithelium.
32
Abboud, SL, and M. Pinzani. "Peptide growth factors stimulate macrophage colony-stimulating factor in murine stromal cells." Blood 78, no. 1 (July 1, 1991): 103–9. http://dx.doi.org/10.1182/blood.v78.1.103.103.
Full textAbstract:
Abstract Bone marrow stromal cells influence hematopoiesis through cell-cell interaction and release of hematopoietic growth factors. Macrophage colony-stimulating factor (M-CSF) is constitutively produced by several murine and human stromal cell lines and is induced by inflammatory mediators such as interleukin-1 alpha or tumor necrosis factor-alpha (TNF-alpha) in a variety of mesenchymal cells. Other potentially important regulatory molecules such as platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF), released by activated monocytes in response to inflammation, stimulate the growth of human stromal cells. However, the effect of these peptide mitogens on M-CSF expression in stromal cells has not been explored. In this study, we used TC-1 murine bone marrow-derived stromal cells that constitutively secrete M-CSF to determine the effect of PDGF and bFGF on cell proliferation and M-CSF gene expression. PDGF and bFGF, but not TNF- alpha, were potent mitogens for the TC-1 cells. Similar to mouse L cells, TC-1 murine stromal cells constitutively expressed two major mRNA transcripts of 4.4 and 2.2 kb that hybridized to a murine M-CSF cDNA. PDGF, bFGF, and TNF-alpha markedly stimulated the steady-state expression of M-CSF mRNA with different time-course kinetics. The increased expression of M-CSF mRNA was associated with enhanced secretion of M-CSF as determined by radioimmunoassay. These findings suggest that PDGF, bFGF, and TNF-alpha may regulate hematopoiesis indirectly through release of M-CSF by stromal cells and may modulate, at least in part, the hematopoietic response to inflammation.
33
Abboud, SL, and M. Pinzani. "Peptide growth factors stimulate macrophage colony-stimulating factor in murine stromal cells." Blood 78, no. 1 (July 1, 1991): 103–9. http://dx.doi.org/10.1182/blood.v78.1.103.bloodjournal781103.
Full textAbstract:
Bone marrow stromal cells influence hematopoiesis through cell-cell interaction and release of hematopoietic growth factors. Macrophage colony-stimulating factor (M-CSF) is constitutively produced by several murine and human stromal cell lines and is induced by inflammatory mediators such as interleukin-1 alpha or tumor necrosis factor-alpha (TNF-alpha) in a variety of mesenchymal cells. Other potentially important regulatory molecules such as platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF), released by activated monocytes in response to inflammation, stimulate the growth of human stromal cells. However, the effect of these peptide mitogens on M-CSF expression in stromal cells has not been explored. In this study, we used TC-1 murine bone marrow-derived stromal cells that constitutively secrete M-CSF to determine the effect of PDGF and bFGF on cell proliferation and M-CSF gene expression. PDGF and bFGF, but not TNF- alpha, were potent mitogens for the TC-1 cells. Similar to mouse L cells, TC-1 murine stromal cells constitutively expressed two major mRNA transcripts of 4.4 and 2.2 kb that hybridized to a murine M-CSF cDNA. PDGF, bFGF, and TNF-alpha markedly stimulated the steady-state expression of M-CSF mRNA with different time-course kinetics. The increased expression of M-CSF mRNA was associated with enhanced secretion of M-CSF as determined by radioimmunoassay. These findings suggest that PDGF, bFGF, and TNF-alpha may regulate hematopoiesis indirectly through release of M-CSF by stromal cells and may modulate, at least in part, the hematopoietic response to inflammation.
34
Ahmad, Aamir, Fazlul H. Sarkar, Main Maitah, Shadan Ali, Seema Sethi, Amro Aboukameel, and Shirish M. Gadgeel. "Effect of GDC-0449, a hedgehog (Hh) pathway inhibitor, on tumor activity and on erlotinib and cisplatin in a xenograft model of non-small cell lung cancer (NSCLC) with activated Hh pathway." Journal of Clinical Oncology 30, no. 15_suppl (May 20, 2012): e21057-e21057. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.e21057.
Full textAbstract:
e21057 Background: We have previously shown that chronic exposure of A549 NSCLC cell line to TGF-β1 can induce epithelial-mesenchymal transition (EMT) and can make these cell lines (A549-M) resistant to erlotinib, an EGFR inhibitor and cisplatin. EMT in A549-M cells was associated with significant activation of signaling through the Hh pathway. We therefore evaluated the activity of GDC-0449, an inhibitor of the Hh pathway, and assessed its activity in combination with erlotinib and cisplatin in A549-M cells both in vitro and in vivo. Methods: We assessed the effects of GDC-0449 (20 nM) on clonogenic growth (colony formation assay), cell motility (wound healing assay) and invasion (matrigel assay) in A549-M cells, and also assessed the activity of GDC-0449 in combination with erlotinib and cisplatin both in vitro (MTT assay) and in an experimental lung metastasis animal model in vivo by injecting A549-M cells through tail vein. Results: A549-M cells showed significantly higher rate of clonogenic growth, cell motility and invasion in vitro and a greater propensity to form metastases in vivo compared to parental A549 cells, and also showed higher resistance to erlotinib and cisplatin. A549-M cells showed higher mRNA levels of Shh (sonic hedgehog, a ligand of the Hh pathway) and ZEB1 and reduced levels of E-cadherin than A549 cells. GDC-0449 significantly reduced growth of A-549-M cell in vitro but had no effect on A-549 cells. GDC-0449 also reduced clonogenic growth, cell motility and invasion of A549-M cells. Pre-treatment with GDC-0449 significantly enhanced the activity of erlotinib (5 and 10 mM) and cisplatin (1mM-10mM) in A549-M cells (p < 0.05) but not in A-549 cells. GDC-0449 reduced the number of lung metastases in the xenograft model and enhanced the activity of erlotinib and cisplatin in this model. Conclusions: This data suggests that the EMT phenotype in NSCLC may be associated with the activation of the Hh signaling pathway. It also suggests that GDC-0449 has anti-tumor activity against NSCLC with activated Hh pathway, and can enhance the effects of erlotinib and cisplatin in such tumors.
35
Krilis, SA, KF Austen, JL Macpherson, CF Nicodemus, MF Gurish, and RL Stevens. "Continuous release of secretory granule proteoglycans from a cell strain derived from the bone marrow of a patient with diffuse cutaneous mastocytosis." Blood 79, no. 1 (January 1, 1992): 144–51. http://dx.doi.org/10.1182/blood.v79.1.144.144.
Full textAbstract:
Abstract A human cell strain (designated HBM-M) that was derived from the bone marrow of a child with diffuse cutaneous mastocytosis was previously found to possess features that suggested it belonged in the mast cell/monocyte lineage. HBM-M cells synthesized approximately 150-Kd Pronase-resistant proteoglycans that were recognized by an antihuman secretory granule proteoglycan peptide core antibody. These cells also contained in relatively high abundance the same sized mRNA transcript that encodes the peptide core of proteoglycans that are normally localized to secretory granules of hematopoietic cells. However, unlike most other hematopoietic cells, HBM-M cells continuously released their newly synthesized 35S-labeled proteoglycans rather than retaining them in an intracellular storage compartment. Chondroitinase ABC, nitrous acid, and heparinase degraded approximately 76%, 17%, and 7%, respectively, of the HBM-M cell-derived 35S-labeled proteoglycans. As assessed by high performance liquid chromatography, 91% of the unsaturated 35S-labeled disaccharides generated by treatment with chondroitinase ABC were delta Di-4S. The remaining chondroitin sulfate 35S-labeled disaccharides appeared to be primarily a complex mixture of disulfated disaccharides. The 35S-labeled glycosaminoglycans that were not degraded by chondroitinase ABC migrated in two-dimensional cellulose acetate electrophoresis as if they were heparan sulfate or under-sulfated heparin. Thus, although the HBM-M cell-derived proteoglycans had some of the features of proteoglycans produced by normal human mast cells, the heparin-like and chondroitin sulfate glycosaminoglycans bound to the HBM-M cell proteoglycans were considerably less sulfated. Because the only human cell types that have so far been shown to synthesize proteoglycans that have heparin-like glycosaminoglycans bound to a protease-resistant peptide core are mast cells and basophilic leukocytes from patients with myelogenous leukemia, it is possible that the HBM-M cell is a mast cell progenitor cell.
36
Krilis, SA, KF Austen, JL Macpherson, CF Nicodemus, MF Gurish, and RL Stevens. "Continuous release of secretory granule proteoglycans from a cell strain derived from the bone marrow of a patient with diffuse cutaneous mastocytosis." Blood 79, no. 1 (January 1, 1992): 144–51. http://dx.doi.org/10.1182/blood.v79.1.144.bloodjournal791144.
Full textAbstract:
A human cell strain (designated HBM-M) that was derived from the bone marrow of a child with diffuse cutaneous mastocytosis was previously found to possess features that suggested it belonged in the mast cell/monocyte lineage. HBM-M cells synthesized approximately 150-Kd Pronase-resistant proteoglycans that were recognized by an antihuman secretory granule proteoglycan peptide core antibody. These cells also contained in relatively high abundance the same sized mRNA transcript that encodes the peptide core of proteoglycans that are normally localized to secretory granules of hematopoietic cells. However, unlike most other hematopoietic cells, HBM-M cells continuously released their newly synthesized 35S-labeled proteoglycans rather than retaining them in an intracellular storage compartment. Chondroitinase ABC, nitrous acid, and heparinase degraded approximately 76%, 17%, and 7%, respectively, of the HBM-M cell-derived 35S-labeled proteoglycans. As assessed by high performance liquid chromatography, 91% of the unsaturated 35S-labeled disaccharides generated by treatment with chondroitinase ABC were delta Di-4S. The remaining chondroitin sulfate 35S-labeled disaccharides appeared to be primarily a complex mixture of disulfated disaccharides. The 35S-labeled glycosaminoglycans that were not degraded by chondroitinase ABC migrated in two-dimensional cellulose acetate electrophoresis as if they were heparan sulfate or under-sulfated heparin. Thus, although the HBM-M cell-derived proteoglycans had some of the features of proteoglycans produced by normal human mast cells, the heparin-like and chondroitin sulfate glycosaminoglycans bound to the HBM-M cell proteoglycans were considerably less sulfated. Because the only human cell types that have so far been shown to synthesize proteoglycans that have heparin-like glycosaminoglycans bound to a protease-resistant peptide core are mast cells and basophilic leukocytes from patients with myelogenous leukemia, it is possible that the HBM-M cell is a mast cell progenitor cell.
37
Kolomytkin, Oleg V., Andrew A. Marino, Kalia K. Sadasivan, Robert E. Wolf, and James A. Albright. "Interleukin-1β switches electrophysiological states of synovial fibroblasts." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 273, no. 5 (November 1, 1997): R1822—R1828. http://dx.doi.org/10.1152/ajpregu.1997.273.5.r1822.
Full textAbstract:
The role of electrophysiological events in signal transduction of interleukin-1β (IL-1β) was investigated in rabbit synovial fibroblasts using the perforated-patch method. Aggregated synovial fibroblasts occurred in two different electrophysiological states having membrane potentials ( V m) of −63 ± 4 ( n = 71) and −27 ± 10 mV ( n = 55) (high and low V m, respectively). IL-1β affected the cells with high V m; it switched the state of the cell from high to low V m. This effect was strongly dependent on the external potential applied to the cell membrane. Low V m(−30 mV) alone without IL-1β did not switch the state of the cells. Thus a synergistic effect involving the cytokine and cell V m in switching the electrophysiological state of the cell was shown, indicating that electrophysiological changes are involved in signal transduction. Gap junctions between aggregated cells were necessary for the cells to have a high V m and to respond to IL-1β. Gap junction resistance between adjacent cells was estimated as 300 ± 100 MΩ. Our findings suggest that the electrophysiological behavior of synovial fibroblasts is tightly connected to a signaling or intracellular mediator system that is triggered by IL-1β.
38
Benardete, Ethan A., Ehud Kaplan, and Bruce W. Knight. "Contrast gain control in the primate retina: P cells are not X-like, some M cells are." Visual Neuroscience 8, no. 5 (May 1992): 483–86. http://dx.doi.org/10.1017/s0952523800004995.
Full textAbstract:
AbstractPrimate retinal ganglion cells that project to the magnocellular layers of the lateral geniculate nucleus (M) are much more sensitive to luminance contrast than those ganglion cells projecting to the parvocellular layers (P). We now report that increasing contrast modifies the temporal-frequency response of M cells, but not of P cells. With rising contrast, the M cells' responses to sinusoidal stimuli show an increasing attenuation at low temporal frequencies while the P cells' responses scale uniformly. The characteristic features of M-cell dynamics are well described by a model originally developed for the X and Y cells of the cat, where the hypothesized nonlinear feedback mechanism responsible for this behavior has been termed the contrast gain control (Shapley & Victor, 1978, 1981; Victor, 1987, 1988). These data provide further physiological evidence that the M-cell pathway differs from the P-cell pathway with regard to the functional elements in the retina. Furthermore, the similarity in dynamics between primate M cells and cat X and Y retinal ganglion cells suggests the possibility that P cells, being different from either group, are a primate specialization not found in the retinae of lower mammals.
39
Zeschnigk, M., D. Kozian, C. Kuch, M. Schmoll, and A. Starzinski-Powitz. "Involvement of M-cadherin in terminal differentiation of skeletal muscle cells." Journal of Cell Science 108, no. 9 (September 1, 1995): 2973–81. http://dx.doi.org/10.1242/jcs.108.9.2973.
Full textAbstract:
Cadherins are a gene family encoding calcium-dependent cell adhesion proteins which are thought to act in the establishment and maintenance of tissue organization. M-cadherin, one member of the family, has been found in myogenic cells of somitic origin during embryogenesis and in the adult. These findings have suggested that M-cadherin is involved in the regulation of morphogenesis of skeletal muscle cells. Therefore, we investigated the function of M-cadherin in the fusion of myoblasts into myotubes (terminal differentiation) in cell culture. Furthermore, we tested whether M-cadherin might influence (a) the expression of troponin T, a typical marker of biochemical differentiation of skeletal muscle cells, and (b) withdrawal of myoblasts from the cell cycle (called terminal commitment). The studies were performed by using antagonistic peptides which correspond to sequences of the putative M-cadherin binding domain. Analogous peptides of N-cadherin have previously been shown to interfere functionally with the N-cadherin-mediated cell adhesion. In the presence of antagonistic M-cadherin peptides, the fusion of myoblasts into myotubes was inhibited. Analysis of troponin T revealed that it was downregulated at the protein level although its mRNA was still detectable. In addition, withdrawal from the cell cycle typical for terminal commitment of muscle cells was not complete in fusion-blocked myogenic cells. Finally, expression of M-cadherin antisense RNA reducing the expression of the endogenous M-cadherin protein interfered with the fusion process of myoblasts. Our data imply that M-cadherin-mediated myoblast interaction plays an important role in terminal differentiation of skeletal muscle cells.
40
van der Merwe, Jacques, Tracy Prysliak, and Jose Perez-Casal. "Invasion of Bovine Peripheral Blood Mononuclear Cells and Erythrocytes by Mycoplasma bovis." Infection and Immunity 78, no. 11 (August 16, 2010): 4570–78. http://dx.doi.org/10.1128/iai.00707-10.
Full textAbstract:
ABSTRACT Mycoplasma bovis is a small, cell wall-less bacterium that contributes to a number of chronic inflammatory diseases in both dairy and feedlot cattle, including mastitis and bronchopneumonia. Numerous reports have implicated M. bovis in the activation of the immune system, while at the same time inhibiting immune cell proliferation. However, it is unknown whether the specific immune-cell population M. bovis is capable of attaching to and potentially invading. Here, we demonstrate that incubation of M. bovis Mb1 with bovine peripheral blood mononuclear cells (PBMC) resulted in a significant reduction in their proliferative responses while still remaining viable and capable of gamma interferon secretion. Furthermore, we show that M. bovis Mb1 can be found intracellularly (suggesting a role for either phagocytosis or attachment/invasion) in a number of select bovine PBMC populations (T cells, B cells, monocytes, γδ T cells, dendritic cells, NK cells, cytotoxic T cells, and T-helper cells), as well as red blood cells, albeit it at a significantly lower proportion. M. bovis Mb1 appeared to display three main patterns of intracellular staining: diffuse staining, an association with the intracellular side of the cell membrane, and punctate/vacuole-like staining. The invasion of circulating immune cells and erythrocytes could play an important role in disease pathogenesis by aiding the transport of M. bovis from the lungs to other sites.
41
Wang, Lei, Brandon L. Walker, Devang Bhatt, Patrick J. Kennedy, and William T. Tse. "Clonal Dedifferentiation of Human Myogenic Progenitors into Skeletal Muscle Stem Cells Induced by MAPK Inhibition." Blood 110, no. 11 (November 16, 2007): 3701. http://dx.doi.org/10.1182/blood.v110.11.3701.3701.
Full textAbstract:
Abstract Understanding the biology of skeletal muscle stem cells can facilitate development of effective cellular therapy for muscle diseases such as muscular dystrophy. While studying human bone marrow stromal cells, we identified a stromal cell subclone, WB15-M, which has developed spontaneously into a skeletal muscle cell line. This subclone no longer expressed CD105, CD90 and CD44, cell surface markers typically found on bone marrow stromal cells. Instead they expressed alpha7-integrin, an antigen found on myoblasts and regenerating muscles. WB15-M cells were positive for the myogenic regulatory factors MyoD and Myf5 and, when cultured under a low-serum condition, matured into multinucleated myofibers that expressed sarcomeric alpha-actinin, myosin heavy chain, dystroglycan and dystrophin, indicating that WB15-M cells were committed myogenic progenitors. We asked if the WB15-M cells might contain skeletal muscle stem cells. Immunofluorescent microscopic studies revealed that rare WB15-M cells expressed Pax7, Pax3 and Msx1, nuclear factors found in skeletal muscle stem cells. When WB15-M cells were cultured in SB203580 or PD98059, inhibitors of the p38 and Erk mitogen-activated protein kinases (MAPK), respectively, they markedly enhanced expression of Pax7, Pax3 and Msx1. The increase in the expression of these nuclear factors could be blocked by simultaneous treatment of WB15-M cells with orthovanadate, a protein tyrosine phosphatase. Alternatively, the increase could be induced by chemically inhibiting Mnk1, a common downstream target of the p38 and Erk MAPK signaling cascades. When further stimulated with bone morphogenic protein-2, MAPK inhibitor-treated WB15-M cells acquired the ability to express alkaline phosphatase, an early osteoblast marker, a property also seen in skeletal muscle stem cells. In contrast, untreated WB15-M cells did not exhibit this property. Clonal analysis showed that the biological changes exhibited by WB15-M cells upon MAPK inhibition was not an artifact of cellular heterogeneity but the result of reversion of individual committed myogenic progenitors to stem cell-like precursors that were more primitive in their development. Purified myogenin-expressing cells that have already initiated their myogenic differentiation program could still revert clonally to these stem cell-like precursors upon MAPK inhibition, indicating a bona fide dedifferentiation process and a true reversal of developmental fate. When WB15-M cells treated with MAPK inhibitors were cultured clonally under conditions that promoted both myogenic and osteogenic development, they formed colonies that expressed either myogenin or alkaline phosphatase but not both; untreated WB15-M cells cultured under the same conditions formed only myogenin-expressing colonies. In conclusion, we found that human bone marrow stromal cell-derived myogenic progenitors could be induced by MAPK inhibition to dedifferentiate into precursors that exhibited properties of the skeletal muscle stem cells. This finding should facilitate the development of novel cellular therapy that utilizes skeletal muscle stem cells.
42
Nair, Vidhya, Haaris Khan, Ron Mitchell, and Michael U. Shiloh. "Role of M Cells in Human Mucosal Immunity to Mycobacterium tuberculosis." Open Forum Infectious Diseases 4, suppl_1 (2017): S48. http://dx.doi.org/10.1093/ofid/ofx162.111.
Full textAbstract:
Abstract Background Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is a bacterial pathogen that infects roughly one-third of the worldÕs population and causes 1–2 million deaths per year. The current paradigm is that phagocytosis of Mtb by patrolling alveolar macrophages initiates Mtb infection. While this model can account for pulmonary TB, it does not adequately explain the occurrence of extrapulmonary forms of TB that manifest in the absence of obvious lung involvement, such as tuberculous cervical lymphadenitis, also known as scrofula. We hypothesized that specialized epithelial cells called microfold cells (M cells) may be an alternate portal of entry for Mtb. Previously we demonstrated that Mtb is able to transcytose across an epithelial barrier in an M cell dependent manner and that M cell mediated transcytosis is vital for Mtb pathogenesis in a mouse model of tuberculosis. Methods We used an in vitro M-cell mediated translocation assay and a Mtb mutant lacking a key virulence factor, ESAT6. We used biochemistry and genetics to identify a novel receptor for ESAT6. We also developed a novel explanted human adenoid Mtb infection model to study mucosal immunity. Results We now demonstrate that the Mtb virulence factor ESAT6 is necessary and sufficient to mediate binding and transcytosis by M cells in vitro and in vivo, and that uptake of Mtb by M cells requires a unique cell surface ESAT6 receptor. We developed a novel explanted human adenoid model of M cell biology and demonstrate rapid Mtb transcytosis by primary human tissue within 60–120 minutes. Using flow cytometry we find that Mtb is first ingested by M cells and then after transcytosis, by tissue resident antigen-presenting cells. Explanted adenoids from 10 independent donors display a wide range of Mtb uptake. Conclusion We conclude that Mtb ESAT6 is necessary for Mtb uptake by M-cells and that binding and transcytosis require a host receptor. Because explanted adenoids display a wide range of Mtb uptake, M cell mediated transcytosis may confer differential susceptibility to scrofula and disseminated disease. These findings are significant as M cells could potentially serve as the basis for novel therapeutic targets against primary Mtb infection. Disclosures All authors: No reported disclosures.
43
Staub, F., A. Winkler, J. Peters, O. Kempski, V. Kachel, and A. Baethmann. "Swelling, Acidosis, and Irreversible Damage of Glial Cells from Exposure to Arachidonic Acid in vitro." Journal of Cerebral Blood Flow & Metabolism 14, no. 6 (November 1994): 1030–39. http://dx.doi.org/10.1038/jcbfm.1994.135.
Full textAbstract:
Swelling and damage of C6 glioma cells and of primary cultured astrocytes were analyzed in vitro during incubation with arachidonic acid (AA; 20:4). The cells were suspended in a physiological medium supplemented with AA at concentrations of 0.001–1.0 m M. Cell swelling was quantified by flow cytometry with hydrodynamic focusing. Flow cytometry was also utilized for assessment of cell viability by exclusion of the fluorescent dye propidium iodide and for measurement of the intracellular pH (pHi) by 2′,7′-bis-(2-carboxyethyl)−5(and −6)carboxyfluorescein. Administration of AA caused an immediate dose-dependent swelling of C6 glioma cells, even at a concentration of 0.01 m M. At this level cell volume increased within 20 min to 105.0% of control, at 0.1 m M to 111.0%, while at 1.0 m M to 123.7%. Following a phase of rapid cell volume increase, swelling leveled off during the subsequent observation period of 70 min. Viability of the C6 glioma cells was 90% under control conditions. It remained unchanged after raising AA concentrations to 0.1 m M. At 0.5 m M, however, cell viability fell to 72.8%, and at 1.0 m M to 32.7%. pHi of the glioma cells was 7.3 under control conditions. In parallel with the early swelling phase, AA led to a dose-dependent decrease of the intracellular pH and an elevated lactate production of the cells. During incubation with 0.1 m M AA, pHi decreased to 7.06 after 5 min, but recovered to normal subsequently. In addition, swelling-inducing properties of linoleic (18:2) or stearic (18:0) acid were analyzed for evaluation of the specificity of glial swelling induced by AA. Whereas stearic acid (0.1 m M) failed to induce a swelling response, linoleic acid (0.1 m M) was found to be effective. The volume increase of the glial cells, however, was only half of that found during exposure to AA at the same concentration. Further, glial swelling from AA or linoleic acid was completely inhibited by the aminosteroid U-74389F, an antagonist of lipid peroxidation. Finally, omission of Na+ ions in the suspension medium with replacement by choline led also to inhibition of the cell volume increase by AA. Experiments using astrocytes from primary culture confirmed the swelling-inducing properties of AA at a quantitative level, whereas vulnerability of the cells to AA was increased. The present results demonstrate an important role of AA in cytotoxic swelling and irreversible damage of glial cells at concentrations that occur in vivo in cerebral ischemia or trauma. The damaging potential of AA might be enhanced by a concurrently evolving intracellular acidosis, stimulating the formation of oxygen-derived free radicals and lipid peroxidation.
44
Moriuchi, Hiroyuki, Masako Moriuchi, and Anthony S. Fauci. "Differentiation of Promonocytic U937 Subclones into Macrophagelike Phenotypes Regulates a Cellular Factor(s) Which Modulates Fusion/Entry of Macrophagetropic Human Immunodeficiency Virus Type 1." Journal of Virology 72, no. 4 (April 1, 1998): 3394–400. http://dx.doi.org/10.1128/jvi.72.4.3394-3400.1998.
Full textAbstract:
ABSTRACT Monocytes/macrophages (M/M) and CD4+ T cells are two important targets of human immunodeficiency virus (HIV) infection. Different strains of HIV-1 vary markedly in their abilities to infect cells belonging to the M/M lineage. Macrophagetropic (M-tropic) HIV-1 strains replicate well in primary lymphocytes as well as in primary macrophages; however, they generally infect T-cell lines poorly, if at all. Although promonocytic cell lines such as U937 have been used as in vitro models of HIV-1 infection of M/M, these cell lines are susceptible to certain T-cell-tropic (T-tropic) HIV-1 strains but are resistant to M-tropic HIV-1. In this study, we demonstrate that (i) certain U937 clones (“plus” clones), which are susceptible only to T-tropic HIV-1, become highly susceptible to M-tropic HIV-1 upon differentiation with retinoic acid (RA); (ii) other U937 clones (“minus” clones), which are resistant to both T- and M-tropic HIV-1, remain resistant to both viruses; and (iii) RA treatment induces expression of CCR5, a fusion/entry cofactor for M-tropic HIV-1 in both types of U937 clones, and yet enhances the fusogenicity of the plus clones, but not the minus clones, with M-tropic Env’s. These results indicate that the major restriction of M-tropic HIV-1 infection in promonocytic cells occurs at the fusion/entry level, that differentiation into macrophage-like phenotypes renders some of these cells highly susceptible to infection with M-tropic HIV-1, and that CD4 and CCR5 may not be the only determinants of fusion/entry of M-tropic HIV-1 in these cells.
45
Matsumura, Yuko, Yasuhiko Ito, Yoshihiro Mezawa, Kaidiliayi Sulidan, Yataro Daigo, Toru Hiraga, Kaoru Mogushi, et al. "Stromal fibroblasts induce metastatic tumor cell clusters via epithelial–mesenchymal plasticity." Life Science Alliance 2, no. 4 (July 22, 2019): e201900425. http://dx.doi.org/10.26508/lsa.201900425.
Full textAbstract:
Emerging evidence supports the hypothesis that multicellular tumor clusters invade and seed metastasis. However, whether tumor-associated stroma induces epithelial–mesenchymal plasticity in tumor cell clusters, to promote invasion and metastasis, remains unknown. We demonstrate herein that carcinoma-associated fibroblasts (CAFs) frequently present in tumor stroma drive the formation of tumor cell clusters composed of two distinct cancer cell populations, one in a highly epithelial (E-cadherinhiZEB1lo/neg: Ehi) state and another in a hybrid epithelial/mesenchymal (E-cadherinloZEB1hi: E/M) state. The Ehi cells highly express oncogenic cell–cell adhesion molecules, such as carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) and CEACAM6 that associate with E-cadherin, resulting in increased tumor cell cluster formation and metastatic seeding. The E/M cells also retain associations with Ehi cells, which follow the E/M cells leading to collective invasion. CAF-produced stromal cell-derived factor 1 and transforming growth factor-β confer the Ehi and E/M states as well as invasive and metastatic traits via Src activation in apposed human breast tumor cells. Taken together, these findings indicate that invasive and metastatic tumor cell clusters are induced by CAFs via epithelial–mesenchymal plasticity.
46
Takami, Akiyoshi, Shigeru Shimadoi, Yukio Kondo, Hirokazu Okumura, and Shinji Nakao. "Monocyte Colony-Stimulating Factor Enhances Rituximab-Dependent Cellular Cytotoxicity by Monocytes." Blood 108, no. 11 (November 16, 2006): 2533. http://dx.doi.org/10.1182/blood.v108.11.2533.2533.
Full textAbstract:
Abstract [Introduction] Recent data suggest that monocytes are the dominant effector cells during immunotherapy using the anti-CD20 monoclonal antibody rituximab, depleting B cells through FcγR-dependent pathways. Because monocyte colony-stimulating factor (M-CSF) enhances the antibody-dependent cellular cytotoxicity (ADCC) of monocytes, the clinical efficacy of rituximab might be improved by the addition of M-CSF. We have studied the effect of M-CSF in the enhancement of rituximab-mediated ADCC against B-cell lymphoma. [Methods] Monocytes were isolated by negative selection of PBMCs from healthy individuals for the absence of T-cell, B-cell, and NK-cell markers. Cytotoxicity was determined by a flow cytometry using two fluorescent dyes, calcein-AM and ethidium homodimer to specifically stain living and dead cells respectively. Monocytes were cultured for 48 hours in the presence or absence of human recombinant M-CSF (66 ng/ml). The B-cell lymphoma cell line Daudi was used as target in the presence of rituximab (5 μg/ml) or human IgG1 as control for 30 min at room temperature. Effector cells and target cells were incubated at different ratios ranging from 1:1 to 15:1 for 4 hours at 37°C. The expression of FcγRl, FcγRII, and FcγRIII on monocytes was determined using a flow cytometry. [Results] Monocytes treated with M-CSF showed a significant increase in rituximab-mediated cytotoxicity against B lymphoma cells: specific lysis at an E:T ratio of 15:1 was 39% ± 7% (mean ± SD) vs. 21% ± 5%, M-CSF-treated monocytes vs. non-treated monocytes. Lysis of lymphoma cells treated with rituximab alone was 8% ± 4%. Treatment with M-CSF led to a 1.5- to 2.0-fold increase of FcγRI and FcγRIII expression in monocytes, while FcγRII expression remained unchanged. [Conclusion] Pretreatment of monocytes with M-CSF enhances their rituximab-mediated ADCC against B-cell lymphoma, which may partly result from increasing expression of FcγRI and FcγRIII on monocytes via M-CSF stimulation. These in vitro results may provide a new approach to improve the therapeutic activity of rituximab.
47
Johnston, J. B., G. Wang, J. W. Barrett, S. H. Nazarian, K. Colwill, M. Moran, and G. McFadden. "Myxoma Virus M-T5 Protects Infected Cells from the Stress of Cell Cycle Arrest through Its Interaction with Host Cell Cullin-1." Journal of Virology 79, no. 16 (August 15, 2005): 10750–63. http://dx.doi.org/10.1128/jvi.79.16.10750-10763.2005.
Full textAbstract:
ABSTRACT The myxoma virus (MV) M-T5 gene encodes an ankyrin repeat protein that is important for virus replication in cells from several species. Insight was gained into the molecular mechanisms underlying the role of M-T5 as a host range determinant when the cell cycle regulatory protein cullin-1 (cul-1) was identified as a cellular binding partner of M-T5 and found to colocalize with the protein in both nuclear and cytosolic compartments. Consistent with this interaction, infection with wild-type MV (vMyxlac) or a deletion mutant lacking M-T5 (vMyxT5KO) differentially altered cell cycle progression in a panel of permissive and nonpermissive cells. Cells infected with vMyxlac transitioned rapidly out of the G0/G1 phase and preferentially accumulated at the G2/M checkpoint, whereas infection with vMyxT5KO impeded progression through the cell cycle, resulting in a greater percentage of cells retained at G0/G1. Levels of the cul-1 substrate, p27/Kip-1, were selectively increased in cells infected with vMyxT5KO compared to vMyxlac, concurrent with decreased phosphorylation of p27/Kip-1 at Thr187 and decreased ubiquitination. Compared to cells infected with vMyxlac, cell death was increased in vMyxT5KO-infected cells following treatment with diverse stimuli known to induce cell cycle arrest, including infection itself, serum deprivation, and exposure to proteasome inhibitors or double-stranded RNA. Moreover, infection with vMyxlac, but not vMyxT5KO, was sufficient to overcome the G0/G1 arrest induced by these stimuli. These findings suggest that M-T5 regulates cell cycle progression at the G0/G1 checkpoint, thereby protecting infected cells from diverse innate host antiviral responses normally triggered by G0/G1 cell cycle arrest.
48
Vorkas, Charles Kyriakos, Olivier Levy, Miroslav Skular, Kelin Li, Jeffrey Aubé, and Michael S. Glickman. "Efficient 5-OP-RU-Induced Enrichment of Mucosa-Associated Invariant T Cells in the Murine Lung Does Not Enhance Control of Aerosol Mycobacterium tuberculosis Infection." Infection and Immunity 89, no. 1 (October 19, 2020): e00524-20. http://dx.doi.org/10.1128/iai.00524-20.
Full textAbstract:
ABSTRACTMucosa-associated invariant T (MAIT) cells are an innate-like T cell subset in mammals that recognize microbial vitamin B metabolites presented by the evolutionarily conserved major histocompatibility complex class I (MHC I)-related molecule, MR1. Emerging data suggest that MAIT cells may be an attractive target for vaccine-induced protection against bacterial infections because of their rapid cytotoxic responses at mucosal services to a widely conserved bacterial ligand. In this study, we tested whether a MAIT cell priming strategy could protect against aerosol Mycobacterium tuberculosis infection in mice. Intranasal costimulation with the lipopeptide Toll-like receptor (TLR)2/6 agonist, Pam2Cys (P2C), and the synthetic MR1 ligand, 5-OP-RU, resulted in robust expansion of MAIT cells in the lung. Although MAIT cell priming significantly enhanced MAIT cell activation and expansion early after M. tuberculosis challenge, these MAIT cells did not restrict M. tuberculosis bacterial load. MAIT cells were depleted by the onset of the adaptive immune response, with decreased detection of granzyme B+ and gamma interferon (IFN-γ)+ MAIT cells relative to that in uninfected P2C/5-OP-RU-treated mice. Decreasing the infectious inoculum, varying the time between priming and aerosol infection, and testing MAIT cell priming in nitric oxide synthase 2 (NOS2)-deficient mice all failed to reveal an effect of P2C/5-OP-RU-induced MAIT cells on M. tuberculosis control. We conclude that intranasal MAIT cell priming in mice induces early MAIT cell activation and expansion after M. tuberculosis exposure, without attenuating M. tuberculosis growth, suggesting that MAIT cell enrichment in the lung is not sufficient to control M. tuberculosis infection.
49
Kim, Young-June, Adam T. Aisen, and Hal E. Broxmeyer. "Myeloid-Derived Suppressor Cell Regulation of PD-1 Expression on, and Longevity of, Human CD8+ T Cells." Blood 112, no. 11 (November 16, 2008): 2562. http://dx.doi.org/10.1182/blood.v112.11.2562.2562.
Full textAbstract:
Abstract Persistent viral infections and tumor burdens are associated with limited longevity of functional CD8+ T cells. Longevity of effector or memory CD8+ T cells may depend on a balance of costimulatory and coinhibitory signals. 4–1BB (CD137), induced as a costimulatory receptor, is known to promote longevity of anti-virus and tumor CD8+ T cells, whereas ‘exhausted’ CD8+ T cells conversely induce coinhibitory receptors such as programmed death-1(PD-1) in order to limit long term CD8+ T cell survival. We hypothesized that myeloid-derived suppressor cells (MDSC) often recruited to the tumor microenvironments might control expression of coinhibitory and costimulatory receptors, thereby regulating longevity of effector and memory CD8+ T cells. To this end, we developed various myeloid-derived dendritic cell (DC) types in vitro from human CD14+ monocytes using M-CSF and GM-CSF in the presence of IL-4 with/without other cytokines, and characterized the DC according to their capacity to regulate expression of CD137 and PD-1 on CD8+ T cells, and their impact on longevity of CD8+ T cells following coculture. In contrast to conventional DC generated with GM-CSF and IL-4 (GM-DC), DC produced with M-CSF and IL-4 (M-DC) were highly suppressive to CD8+ T cell cytotoxic activity, inhibiting induction of costimulatory CD137 on CD8+ T cells during allogeneic cell coculture. M-DC generated in the presence of IL-10 (IL-10/M-DC) uniquely induced inhibitory PD-1 in CD8+ T cells, while maintaining the ability to inhibit stimulatory CD137 expression. The presence of TNF-α or LPS during IL-10/M-DC development, on the other hand, deprived the DC of their PD-1 inducing ability. This suggests that pro-inflammatory factors may have converted IL-10/M-DC into a more mature form of DC that no longer possesses the ability to induce PD-1. Expression of the ligand for PD-1 (PD-L1) in M-DCs was increased greatly by IL-10. Importantly, IL-10/M-DC significantly reduced CD8+ T cell viability during coculture. TGF-β, known to demonstrate similar immune suppressive activities as IL-10, failed to promote M-DC to induce PD-1 on CD8+ T cells, suggesting that IL-10 plays a unique role in inducing PD-1 on CD8+ T cells through M-DC. Neither IL-10 nor M-DC alone affected PD-1 expression on CD8+ T cells. We then evaluated whether IL-10/M-DC affected expression of Sirt1, an NAD+-dependent deacetylase known to extend life span of many cell types, in CD8+ T cells. Sirt1 was detected at only marginal levels in freshly isolated naïve CD8+ T cells, but its expression was increased upon CD3 activation. Coculture with IL-10/M-DC reduced induction of Sirt1 in anti-CD3 activated CD8+ T cells. Various immune suppressive cells are found in tumor microenvironments and chronically virus infected patients. Our results suggest that IL-10/M-DC may play a role as immune suppressor cells in evasion of a host’s immune system by tumors and viruses, via modulation of CD137 and PD-1 signals, both of which affect longevity of CD8+ T cells. Longevity may relate to expression of Sirt1.
50
Okumura, Daiki, Mari Hagino, Akane Yamagishi, Yuichiro Kaibori, Sirajam Munira, Youhei Saito, and Yuji Nakayama. "Inhibitors of the VEGF Receptor Suppress HeLa S3 Cell Proliferation via Misalignment of Chromosomes and Rotation of the Mitotic Spindle, Causing a Delay in M-Phase Progression." International Journal of Molecular Sciences 19, no. 12 (December 12, 2018): 4014. http://dx.doi.org/10.3390/ijms19124014.
Full textAbstract:
Cell division is the process by which replicated chromosomes are separated into two daughter cells. Although regulation of M phase has been extensively investigated, not all regulating factors have been identified. Over the course of our research, small molecules were screened to identify those that regulate M phase. In the present study, the vascular endothelial growth factor receptor (VEGFR) inhibitors A83-01, SU4312, and Ki8751 were examined to determine their effects on M phase. Treatment of HeLa S3 cells with these inhibitors suppressed cell proliferation in a concentration-dependent manner, and also suppressed Akt phosphorylation at Ser473, a marker of Akt activation. Interestingly, cleaved caspase-3 was detected in Adriamycin-treated cells but not in inhibitor-treated cells, suggesting that these inhibitors do not suppress cell proliferation by causing apoptosis. A cell cycle synchronization experiment showed that these inhibitors delayed M phase progression, whereas immunofluorescence staining and time-lapse imaging revealed that the M phase delay was accompanied by misalignment of chromosomes and rotation of the mitotic spindle. Treatment with the Mps1 inhibitor AZ3146 prevented the SU4312-induced M phase delay. In conclusion, the VEGFR inhibitors investigated here suppress cell proliferation by spindle assembly checkpoint-induced M phase delay, via misalignment of chromosomes and rotation of the mitotic spindle.