Journal articles: 'PLDN'

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Mao, Guangfen, Chengxiang Fan, Gauthami Jalagadugula, Robert Freishtat, and A. Koneti Rao. "RUNX1 Regulates PLDN (Pallidin) Expression In Platelets: A Potential Mechanism For Dense Granule Deficiency In RUNX1 Haplodeficiency." Blood 122, no. 21 (November 15, 2013): 567. http://dx.doi.org/10.1182/blood.v122.21.567.567.

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Abstract Transcription factor RUNX1 plays a major role in hematopoiesis. Haplodeficiency of RUNX1 is associated with familial thrombocytopenia, impaired platelet function and megakaryopoiesis, and predisposition to acute myeloid leukemia. Platelet abnormalities include impaired aggregation, secretion, protein phosphorylation, and activation of GPIIb-IIIa on platelet activation. Dense granule deficiency, either alone or in combination with alpha granule deficiency, has been reported in patients with RUNX1 haplodeficiency, but the mechanisms involved are unknown. We have reported a patient with inherited thrombocytopenia and abnormal platelet function (Gabbeta et al, Blood 87:1368-76, 1996) associated with a heterozygous nonsense mutation in transcription factor RUNX1 (Sun et al, Blood 103: 948-54, 2004). The platelets showed impaired aggregation, dense granule secretion, phosphorylation of pleckstrin and myosin light chain, diminished GPIIb-IIIa activation and decreased platelet protein kinase C-θ. Platelet mRNA expression profiling showed downregulation of several genes, including myosin light chain 9 (MYL9), platelet factor 4 (PF4), protein kinase C-θ (PRKB), and 12-lipoxygenase (ALOX12) in the patient compared to 6 normal subjects (Sun et al, J. Thromb Haemost. 5: 146-54, 2007). (We have shown that these genes are direct transcriptional targets of RUNX1.) In addition, PLDN, which encodes for protein pallidin, was four-fold down-regulated in platelets (fold change 0.239, p=0.029). In mouse model pallid, knock out of pldn leads to dense granule deficiency. Recent reports document mutations in PLDN in human subjects with platelet dense granule deficiency and the Hermansky-Pudlak syndrome. Pallidin is one of 8 subnunits that constitute the BLOC-1 (biogenesis of lysosome-related organelles complex-1), which plays a major role in granule/vesicle biogenesis. PLDN has two known human transcripts; PLDN1 is expressed ubiquitously, with exception of brain, while PLDN2 is expressed in brain, testes and leukocytes. We have addressed that PLDN is a direct transcriptional target of RUNX1 and hypothesize that its decreased expression constitutes a mechanism for the platelet dense granule deficiency in patients with RUNX1 haplodeficiency. We validated the decreased expression of PLDN on platelet profiling by quantitative real-time PCR - PLDN1 mRNA expression was decreased by 16-fold in the patient relative to normal subjects. We studied the regulation of PLDN1 by RUNX1 in human erythroleukemia (HEL) cells treated with phorbol 12-myristate 13-acetate (PMA) for 24 h to induce megakaryocytic transformation. In silico analyses revealed the presence of 6 RUNX1 consensus binding sites in 2288bp of PLDN1 5’ upstream region from ATG. To determine endogenous interaction of RUNX1 with PLDN promoter, we performed chromatin immunoprecipitation (ChIP) assay using anti-RUNX1 antibody. There was RUNX1 binding to PLDN chromatin at regions encompassing the putative RUNX1 binding site 1 (-184 to -179 bp) and site 3 (-1370/-1365 bp). We performed electrophoretic mobility shift assay (EMSA) using probes with RUNX1 motifs and PMA-treated HEL cell nuclear extracts. With 30–34 bp probes encompassing site 1 (-184 to -179 bp) and site 3 (-1370 to -1365 bp), protein binding was observed that was competed by excess unlabelled probe and inhibited by anti-RUNX1 antibody indicating RUNX1 as the protein involved. To study the functional effect of the binding sites, the wild type PLDN1 promoter construct –2288/-2 bp containing the putative RUNX1 sites or mutant constructs with each site individually mutated were cloned into firefly luciferase reporter gene vector and transfected into HEL cells. Mutation of RUNX1 sites 1 and 3 individually caused 60-70% reduction in promoter activity indicating that these sites were functional. Studies on the other RUNX1 consensus sites in PLDN promoter are underway. Conclusions Our results provide the first evidence that PLDN gene is transcriptionally regulated by and is a direct target of RUNX1. These studies provide a cogent mechanism for the PLDN transcript downregulation observed in the patient platelets. More importantly, they provide a mechanism for the dense granule deficiency and impaired vesicle formation associated with RUNX1 haplodeficiency. Disclosures: No relevant conflicts of interest to declare.

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Oliveira, Erik Da Silva. "Algoritmo identificador de vértices viáveis para solução do PLDN." REVISTA PRODUÇÃO E ENGENHARIA 1, no. 1 (January 24, 2016): 13. http://dx.doi.org/10.18407/issn.1983-9952.2008.v1.n1.p13-26.

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Devido à grande competitividade mundial, as organizações estão preocupadas com a otimização de seus processos produtivos inseridos em ambientes sinérgicos, mutáveis e hierarquizados. A pesquisa operacional é uma metodologia decisória com algoritmos que buscam a otimização desses processos. A programação linear em dois níveis (PLDN) é um modelo de Pesquisa Operacional que representa bem operações de produção que dependem de dois níveis hierárquicos de decisão. Assim, com o modelo de PLDN encontra-se uma solução compatível com os interesses de dois níveis decisórios distintos, sendo cada um deles governado por uma parcela de variáveis que interagem nas restrições do modelo. O algoritmo identificador de vértices viáveis é um método que reconhece todos os pontos extremos viáveis do PLDN, sendo sua implementação em MATLAB bastante eficiente no entendimento dos resultados teóricos do PLDN.

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Falcn-Prez, Juan M., and Esteban C. Dell'angelica. "ThePallidin(Pldn) Gene and the Role of SNARE Proteins in Melanosome Biogenesis." PIGMENT CELL RESEARCH 15, no. 2 (April 2002): 82–86. http://dx.doi.org/10.1034/j.1600-0749.2002.1r082.x.

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Chao, Chi-Chao, Ming-Tsung Tseng, Paul-Chen Hsieh, Chien-Ho (Janice) Lin, Shin-Leh Huang, Sung-Tsang Hsieh, and Ming-Chang Chiang. "Brain Mechanisms of Pain and Dysautonomia in Diabetic Neuropathy: Connectivity Changes in Thalamus and Hypothalamus." Journal of Clinical Endocrinology & Metabolism 107, no. 3 (October 19, 2021): e1167-e1180. http://dx.doi.org/10.1210/clinem/dgab754.

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Abstract Context About one-third of diabetic patients suffer from neuropathic pain, which is poorly responsive to analgesic therapy and associated with greater autonomic dysfunction. Previous research on diabetic neuropathy mainly links pain and autonomic dysfunction to peripheral nerve degeneration resulting from systemic metabolic disturbances, but maladaptive plasticity in the central pain and autonomic systems following peripheral nerve injury has been relatively ignored. Objective This study aimed to investigate how the brain is affected in painful diabetic neuropathy (PDN), in terms of altered structural connectivity (SC) of the thalamus and hypothalamus that are key regions modulating nociceptive and autonomic responses. Methods We recruited 25 PDN and 13 painless (PLDN) diabetic neuropathy patients, and 27 healthy adults as controls. The SC of the thalamus and hypothalamus with limbic regions mediating nociceptive and autonomic responses was assessed using diffusion tractography. Results The PDN patients had significantly lower thalamic and hypothalamic SC of the right amygdala compared with the PLDN and control groups. In addition, lower thalamic SC of the insula was associated with more severe peripheral nerve degeneration, and lower hypothalamic SC of the anterior cingulate cortex was associated with greater autonomic dysfunction manifested by decreased heart rate variability. Conclusion Our findings indicate that alterations in brain structural connectivity could be a form of maladaptive plasticity after peripheral nerve injury, and also demonstrate a pathophysiological association between disconnection of the limbic circuitry and pain and autonomic dysfunction in diabetes.

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Hellinger, Johannes, Stefan Stern, and Stefan Hellinger. "Nonendoscopic Nd-YAG 1064 nm PLDN in the Treatment of Thoracic Discogenic Pain Syndromes." Journal of Clinical Laser Medicine & Surgery 21, no. 2 (April 2003): 61–66. http://dx.doi.org/10.1089/104454703765035475.

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&NA;. "LAPAROSCOPIC DONOR NEPHRECTOMY (LDN): ROBOTIC-ASSISTED (RALDN) VS PURE (PLDN) VS HAND-ASSISTED (HALDN)." Transplantation 82, Suppl 2 (July 2006): 796–97. http://dx.doi.org/10.1097/00007890-200607152-02200.

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Iuele, Francesca, Dino Rubini, Corinna Altini, Paolo Mammucci, and Antonio Rosario Pisani. "Lympho-SPECT/CT as a Key Tool in the Management of a Patient with Chylous Ascites." Biomedicines 11, no. 2 (January 19, 2023): 282. http://dx.doi.org/10.3390/biomedicines11020282.

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Chylous ascites is a rare form of ascites usually associated with cirrhosis, abdominal malignancies, surgeries or infections. We presented a case of chylous ascites after robotic laparoscopic prostatectomy (PLDN-RALP), in which the correct diagnosis was achieved by SPECT/CT lymphoscintigraphy. A 72-year-old male developed chylous ascites after surgery and underwent lymphoscintigraphy with radiolabeled albumin nanocolloids for the supplementary study of the lymph flow and to detect a possible site of leakage. The scintigraphic imaging demonstrated the abdominal effusion and lymph stasis in the left iliac region. The combination of planar imaging with SPECT/CT can resolve the assessment of chylous disorders.

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Cullinane, Andrew R., James A. Curry, Carmelo Carmona-Rivera, C. Gail Summers, Carla Ciccone, Nicholas D. Cardillo, Heidi Dorward, et al. "RETRACTED: A BLOC-1 Mutation Screen Reveals that PLDN Is Mutated in Hermansky-Pudlak Syndrome Type 9." American Journal of Human Genetics 88, no. 6 (June 2011): 778–87. http://dx.doi.org/10.1016/j.ajhg.2011.05.009.

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Cullinane, Andrew R., James A. Curry, Carmelo Carmona-Rivera, C. Gail Summers, Carla Ciccone, Nicholas D. Cardillo, Heidi Dorward, et al. "Retraction Notice to: A BLOC-1 Mutation Screen Reveals that PLDN Is Mutated in Hermansky-Pudlak Syndrome Type 9." American Journal of Human Genetics 100, no. 5 (May 2017): 837. http://dx.doi.org/10.1016/j.ajhg.2017.04.011.

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COLLEY, William C., Yelena M. ALTSHULLER, Christopher K. SUE-LING, Neal G. COPELAND, Debra J. GILBERT, Nancy A. JENKINS, Kimberly D. BRANCH, et al. "Cloning and expression analysis of murine phospholipase D1." Biochemical Journal 326, no. 3 (September 15, 1997): 745–53. http://dx.doi.org/10.1042/bj3260745.

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Activation of phosphatidylcholine-specific phospholipase D (PLD) occurs as part of the complex signal-transduction cascade initiated by agonist stimulation of tyrosine kinase and G-protein-coupled receptors. A variety of mammalian PLD activities have been described, and cDNAs for two PLDs recently reported (human PLD1 and murine PLD2). We describe here the cloning and chromosomal localization of murine PLD1. Northern-blot hybridization and RNase protection analyses were used to examine the expression of murine PLD1 and PLD2 in a variety of cell lines and tissues. PLD1 and PLD2 were expressed in all RNA samples examined, although the absolute expression of each isoform varied, as well as the ratio of PLD1 to PLD2. Moreover, in situhybridization of adult brain and murine embryo sections revealed high levels of expression of individual PLDs in some cell types and no detectable expression in others. Thus the two PLDs probably carry out distinct roles in restricted subsets of cells rather than ubiquitous roles in all cells.

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Galsky, Matt D., Andrea Necchi, Neal D. Shore, Elizabeth R. Plimack, Calvin Jia, Eric Sbar, Blanca Homet Moreno, and Johannes Alfred Witjes. "KEYNOTE-905/EV-303: Perioperative pembrolizumab or pembrolizumab plus enfortumab vedotin (EV) and cystectomy compared to cystectomy alone in cisplatin-ineligible patients with muscle-invasive bladder cancer (MIBC)." Journal of Clinical Oncology 39, no. 6_suppl (February 20, 2021): TPS507. http://dx.doi.org/10.1200/jco.2021.39.6_suppl.tps507.

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TPS507 Background: Patients with MIBC who are ineligible for neoadjuvant cisplatin-based chemotherapy receive the standard-of-care treatment of radical cystectomy (RC) and pelvic lymph node dissection (PLND); however, RC + PLND alone is associated with high rates of recurrence and relatively poor overall survival (OS). The PURE-01 study (NCT02736266) demonstrated a pathologic complete response (pCR) rate of 37% (95% CI, 28%-36%) with neoadjuvant pembrolizumab in MIBC (Necchi, Eur Urol, 2020). The combination of pembrolizumab plus EV demonstrated encouraging antitumor activity in metastatic urothelial cancer (Rosenberg, ASCO GU, 2020). KEYNOTE-905/EV-303 (NCT03924895) is a randomized, multinational phase 3 study that will assess efficacy and safety of perioperative pembrolizumab plus RC + PLND versus perioperative EV with pembrolizumab plus RC + PLDN versus RC + PLND alone for patients with MIBC. Methods: Approximately 836 patients will be randomly assigned 1:1:1 to 3 cycles of neoadjuvant pembrolizumab followed by RC + PLND and 14 cycles of adjuvant pembrolizumab or 3 cycles of neoadjuvant EV and pembrolizumab followed by RC+PLND and 6 cycles of adjuvant EV and pembrolizumab and then 8 cycles of adjuvant pembrolizumab or RC + PLND alone. Neoadjuvant or adjuvant pembrolizumab 200 mg will be administered intravenously every 3 weeks (Q3W). Neoadjuvant or adjuvant EV 1.25 mg/kg will be administered on days 1 and 8 Q3W. Stratification factors will be PD-L1 status (combined positive score [CPS] ≥10 vs < 10), disease stage (T2N0 vs T3/T4N0 vs T1-T4aN1), and region (United States vs European Union vs most of the world). Adults with histologically confirmed MIBC (T2-T4aN0M0 or T1-T4aN1M0) with predominant (≥50%) urothelial histology will be enrolled. These patients must also be previously untreated with systemic therapies for MIBC, be ineligible for cisplatin, have Eastern Cooperative Oncology Group performance status of 0-2, and have tumor tissue for histology and PD-L1 analysis. Imaging (CT or MRI) will be performed 5 weeks or fewer before cystectomy and at 6 weeks after cystectomy. Scans will then be performed every 12 weeks up to year 2 after cystectomy and at discontinuation. At year 3 and beyond imaging will be every 24 weeks. Coprimary end points are pCR and event-free survival (EFS) (expressing PD-L1 [CPS ≥10] and all patients regardless of CPS). Secondary end points are OS, disease-free survival, pathologic downstaging, safety, and patient-reported outcomes. Adverse events graded according to Common Terminology Criteria for Adverse Events v4.0 will be monitored from randomization through 30 days after last dose of study drug (90 days for serious adverse events). KEYNOTE-905/EV-303 is ongoing or planned in 25 countries across Asia, Australia, Europe, and North America. Clinical trial information: NCT03924895.

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Onallah, Hadil, Sheethal Thomas Mannully, Ben Davidson, and Reuven Reich. "Exosome Secretion and Epithelial-Mesenchymal Transition in Ovarian Cancer Are Regulated by Phospholipase D." International Journal of Molecular Sciences 23, no. 21 (October 31, 2022): 13286. http://dx.doi.org/10.3390/ijms232113286.

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Phospholipase D (PLD) isoenzymes participate in a variety of cellular functions that are mostly attributed to phosphatidic acid (PA) synthesis. Dysregulation of PLD regulates tumor progression and metastasis, yet little is known about the underlying mechanism. We previously reported on the expression and clinical role of the PLD isoenzymes PLD1 and PLD2 in tubo-ovarian high-grade serous carcinoma (HGSC). In the present study, we investigated the biological function of PLD1 and PLD2 using the OVCAR-3 and OVCAR-8 HGSC cell lines. KO cell lines for both PLDs were generated using CRISPR/CAS9 technology and assayed for exosome secretion, spheroid formation, migration, invasion and expression of molecules involved in epithelial-mesenchymal transition (EMT) and intracellular signaling. Significant differences between PLD1 and PLD2 KO cells and controls were observed for all the above parameters, supporting an important role for PLD in regulating migration, invasion, metastasis and EMT.

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YAMADA, Momoko, Yoshiko BANNO, Yoh TAKUWA, Masahiro KODA, Akira HARA, and Yoshinori NOZAWA. "Overexpression of phospholipase D prevents actinomycin D-induced apoptosis through potentiation of phosphoinositide 3-kinase signalling pathways in Chinese-hamster ovary cells." Biochemical Journal 378, no. 2 (March 1, 2004): 649–56. http://dx.doi.org/10.1042/bj20031398.

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To examine the roles of PLD (phospholipase D) in the regulation of the apoptotic process, PLD1 and PLD2 were stably overexpressed in S1P3-CHO cells [CHO (Chinese-hamster ovary) cells expressing the S1P (sphingosine 1-phosphate) receptor S1P3]. Treatment of S1P3-CHO cells with ActD (actinomycin D) induced apoptosis, as shown by the occurrence of nuclear fragmentation and the caspase-dependent proteolytic cleavage of PARP [poly(ADP-ribose) polymerase] and protein kinase Cδ. Overexpression of either PLD1 or PLD2 protected S1P3-CHO cells from ActD-induced apoptosis, as demonstrated by an increased number of viable cells and inhibition of PARP and protein kinase Cδ cleavage. However, in the early phase of apoptosis, ActD induced an increase in PLD activity and activation of key factors in the cell-survival signalling pathways, such as PI3K (phosphoinositide 3-kinase), Akt, p70S6K (p70 S6 kinase) and ERK (extracellular-signal-regulated kinase). Furthermore, the ActD-induced activation of these survival signalling enzymes was potentiated by overexpression of either PLD1 or PLD2. The PI3K inhibitor LY294002 inhibited the ActD-induced activation of Akt and p70S6K, and completely abolished the effects of PLD1 or PLD2, whereas inhibition of ERK activity by the MEK inhibitor U0126 had a milder effect. The ActD-induced activation of p70S6K and ERKs was blocked by 1-butanol, but not by t-butanol; similar to S1P, exogenous PLD suppressed the ActD-induced events in the apoptosis signalling pathways. These results show that, in S1P3-CHO cells, increased expression of PLDs prevents ActD-induced apoptosis by enhanced activation of the PI3K signalling pathways.

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Bermúdez, Vicente, Paula Estefanía Tenconi, María Sol Echevarría, Aram Asatrian, Jorgelina Muriel Calandria, Norma María Giusto, Nicolas Guillermo Bazan, and Melina Valeria Mateos. "Targeting Phospholipase D Pharmacologically Prevents Phagocytic Function Loss of Retinal Pigment Epithelium Cells Exposed to High Glucose Levels." International Journal of Molecular Sciences 23, no. 19 (October 5, 2022): 11823. http://dx.doi.org/10.3390/ijms231911823.

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We previously described the participation of canonical phospholipase D isoforms (PLD1 and PLD2) in the inflammatory response of retinal pigment epithelium (RPE) cells exposed to high glucose concentrations (HG). Here, we studied the role of the PLD pathway in RPE phagocytic function. For this purpose, ARPE-19 cells were exposed to HG (33 mM) or to normal glucose concentration (NG, 5.5 mM) and phagocytosis was measured using pHrodo™ green bioparticles® or photoreceptor outer segments (POS). HG exposure for 48 and 72 h reduced phagocytic function of ARPE-19 cells, and this loss of function was prevented when cells were treated with 5 μM of PLD1 (VU0359595 or PLD1i) or PLD2 (VU0285655-1 or PLD2i) selective inhibitors. Furthermore, PLD1i and PLD2i did not affect RPE phagocytosis under physiological conditions and prevented oxidative stress induced by HG. In addition, we demonstrated PLD1 and PLD2 expression in ABC cells, a novel human RPE cell line. Under physiological conditions, PLD1i and PLD2i did not affect ABC cell viability, and partial silencing of both PLDs did not affect ABC cell POS phagocytosis. In conclusion, PLD1i and PLD2i prevent the loss of phagocytic function of RPE cells exposed to HG without affecting RPE function or viability under non-inflammatory conditions.

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Ahn, Bong-Hyun, Shi Yeon Kim, Eun Hee Kim, Kyeong Sook Choi, Taeg Kyu Kwon, Young Han Lee, Jong-Soo Chang, Myung-Suk Kim, Yang-Hyeok Jo, and Do Sik Min. "Transmodulation between Phospholipase D and c-Src Enhances Cell Proliferation." Molecular and Cellular Biology 23, no. 9 (May 1, 2003): 3103–15. http://dx.doi.org/10.1128/mcb.23.9.3103-3115.2003.

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ABSTRACT Phospholipase D (PLD) has been implicated in the signal transduction pathways initiated by several mitogenic protein tyrosine kinases. We demonstrate for the first time that most notably PLD2 and to a lesser extent the PLD1 isoform are tyrosine phosphorylated by c-Src tyrosine kinase via direct association. Moreover, epidermal growth factor induced tyrosine phosphorylation of PLD2 and its interaction with c-Src in A431 cells. Interaction between these proteins is via the pleckstrin homology domain of PLD2 and the catalytic domain of c-Src. Coexpression of PLD1 or PLD2 with c-Src synergistically enhances cellular proliferation compared with expression of either molecule. While PLD activity as a lipid-hydrolyzing enzyme is not affected by c-Src, wild-type PLDs but not catalytically inactive PLD mutants significantly increase c-Src kinase activity, up-regulating c-Src-mediated paxillin phosphorylation and extracellular signal-regulated kinase activity. These results demonstrate the critical role of PLD catalytic activity in the stimulation of Src signaling. In conclusion, we provide the first evidence that c-Src acts as a kinase of PLD and PLD acts as an activator of c-Src. This transmodulation between c-Src and PLD may contribute to the promotion of cellular proliferation via amplification of mitogenic signaling pathways.

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BANNO, Yoshiko, Yoh TAKUWA, Momoko YAMADA, Noriko TAKUWA, Kenji OHGUCHI, Akira HARA, and Yoshinori NOZAWA. "Involvement of phospholipase D in insulin-like growth factor-I-induced activation of extracellular signal-regulated kinase, but not phosphoinositide 3-kinase or Akt, in Chinese hamster ovary cells." Biochemical Journal 369, no. 2 (January 15, 2003): 363–68. http://dx.doi.org/10.1042/bj20021368.

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Available evidence suggests the involvement of phospholipase D (PLD) in cell proliferation and survival. Phosphoinositide 3-kinase (PI 3-kinase)/Akt and extracellular signal-regulated kinases (ERKs) are signalling molecules that have essential roles in cell proliferation and survival. We previously demonstrated that sphingosine 1-phosphate (S1P)-induced PLD activation via the G-protein-coupled receptor endothelial differentiation gene (EDG) 3/S1P3 was involved in S1P-induced stimulation of PI 3-kinase and Akt. In the present study, we examined the involvement of two PLD isozymes, PLD1 and PLD2, in insulin-like growth factor (IGF)-I receptor tyrosine kinase-mediated stimulation of PI 3-kinase/Akt and ERKs. IGF-I and to a lesser degree S1P stimulated PI 3-kinase activity in Chinese hamster ovary cells overexpressing EDG3/S1P3. IGF-I-induced ERK phosphorylation was suppressed by butan-1-ol, but not butan-2-ol, whereas no effect of butanol was observed in IGF-I-induced Akt activation in S1P3-overexpressing Chinese hamster ovary cells. Overexpression of wild-type PLD1 and PLD2 substantially potentiated S1P-, but not IGF-I-, induced activation of PI 3-kinase and Akt, whereas overexpression of the catalytically inactive mutant of PLD1 or PLD2 did not affect the responses to either agonist. On the other hand, overexpression of wild-type PLD1 and PLD2 potentiated IGF-I- and, to much smaller extents, S1P-induced ERK stimulation. ERK activation by IGF-I as well as S1P was dependent on Ras, but Akt activation by IGF-I was not dependent on Ras. These results suggest that PLDs are involved in growth factor regulation of at least two signalling pathways, PI 3-kinase/Akt and ERKs, depending on the class of cell-surface receptors.

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Lien, Li-Ming, Wan-Jung Lu, Ting-Yu Chen, Tzu-Yin Lee, Hsueh-Hsiao Wang, Hsien-Yu Peng, Ray-Jade Chen, and Kuan-Hung Lin. "Phospholipase D1 and D2 Synergistically Regulate Thrombus Formation." International Journal of Molecular Sciences 21, no. 18 (September 22, 2020): 6954. http://dx.doi.org/10.3390/ijms21186954.

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Previously, we reported that phospholipase D1 (PLD1) and PLD2 inhibition by selective PLD1 and PLD2 inhibitors could prevent platelet aggregation in humans, but not in mice. Moreover, only the PLD1 inhibitor, but not PLD2 inhibitor, could effectively prevent thrombus formation in mice, indicating that PLD might play different roles in platelet function in humans and mice. Although PLD1 and PLD2 were reported to be implicated in thrombotic events, the role of PLD in mice remains not completely clear. Here, we investigated the role of PLD1 and PLD2 in acute pulmonary thrombosis and transient middle cerebral artery occlusion-induced brain injury in mice. The data revealed that inhibition of PLD1, but not of PLD2, could partially prevent pulmonary thrombosis-induced death. Moreover, concurrent PLD1 and PLD2 inhibition could considerably increase survival rate. Likewise, inhibition of PLD1, but not PLD2, partially improved ischemic stroke and concurrent inhibition of PLD1, and PLD2 exhibited a relatively better protection against ischemic stroke, as evidenced by the infarct size, brain edema, modified neurological severity score, rotarod test, and the open field test. In conclusion, PLD1 might play a more important role than PLD2, and both PLD1 and PLD2 could act synergistically or have partially redundant functions in regulating thrombosis-relevant events.

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Horn, Jeffrey M., Jason A. Lehman, Gerald Alter, Joel Horwitz, and Julian Gomez-Cambronero. "Presence of a phospholipase D (PLD) distinct from PLD1 or PLD2 in human neutrophils: immunobiochemical characterization and initial purification." Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids 1530, no. 1 (January 2001): 97–110. http://dx.doi.org/10.1016/s1388-1981(00)00172-4.

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O'Luanaigh, Niamh, Raul Pardo, Amanda Fensome, Victoria Allen-Baume, David Jones, Mark R. Holt, and Shamshad Cockcroft. "Continual Production of Phosphatidic Acid by Phospholipase D Is Essential for Antigen-stimulated Membrane Ruffling in Cultured Mast Cells." Molecular Biology of the Cell 13, no. 10 (October 2002): 3730–46. http://dx.doi.org/10.1091/mbc.e02-04-0213.

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Phospholipase Ds (PLDs) are regulated enzymes that generate phosphatidic acid (PA), a putative second messenger implicated in the regulation of vesicular trafficking and cytoskeletal reorganization. Mast cells, when stimulated with antigen, show a dramatic alteration in their cytoskeleton and also release their secretory granules by exocytosis. Butan-1-ol, which diverts the production of PA generated by PLD to the corresponding phosphatidylalcohol, was found to inhibit membrane ruffling when added together with antigen or when added after antigen. Inhibition by butan-1-ol was completely reversible because removal of butan-1-ol restored membrane ruffling. Measurements of PLD activation by antigen indicate a requirement for continual PA production during membrane ruffling, which was maintained for at least 30 min. PLD1 and PLD2 are both expressed in mast cells and green fluorescent protein-tagged proteins were used to identify PLD2 localizing to membrane ruffles of antigen-stimulated mast cells together with endogenous ADP ribosylation factor 6 (ARF6). In contrast, green fluorescent protein-PLD1 localized to intracellular vesicles and remained in this location after stimulation with antigen. Membrane ruffling was independent of exocytosis of secretory granules because phorbol 12-myristate 13-acetate increased membrane ruffling in the absence of exocytosis. Antigen or phorbol 12-myristate 13-acetate stimulation increased both PLD1 and PLD2 activity when expressed individually in RBL-2H3 cells. Although basal activity of PLD2-overexpressing cells is very high, membrane ruffling was still dependent on antigen stimulation. In permeabilized cells, antigen-stimulated phosphatidylinositol(4,5)bisphosphate synthesis was dependent on both ARF6 and PA generated from PLD. We conclude that both activation of ARF6 by antigen and a continual PLD2 activity are essential for local phosphatidylinositol(4,5)bisphosphate generation that regulates dynamic actin cytoskeletal rearrangements.

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Gavin, Amanda L., Deli Huang, and David Nemazee. "The ssDNA exonucleases PLD3 and PLD4 are required to prevent lethal primary HLH-like disease in mice." Journal of Immunology 202, no. 1_Supplement (May 1, 2019): 187.6. http://dx.doi.org/10.4049/jimmunol.202.supp.187.6.

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Abstract Leukocyte sensing of microbial genetic material often elicits beneficial proinflammatory cytokines, but dysregulated responses can cause severe pathogenesis. Genome-wide association studies have linked Phospholipase D3 (PLD3) to Alzheimer’s disease and PLD4 to rheumatoid arthritis and systemic sclerosis. PLD3 and PLD4 are endolysosomal proteins with no detectable phospholipase activity. PLD4 deficient mice have a mild inflammatory disease, marked by elevated interferon-γ (IFN γ) and splenomegaly. These phenotypes were traced to an altered responsiveness of PLD4-deficient dendritic cells to ligands of the single-stranded DNA (ssDNA) sensor Toll-like receptor 9 (TLR9). Thioglycolate elicited peritoneal macrophages from PLD3-deficient mice also had exaggerated TLR9 responses to particular ligands. Although PLD4 and PLD3 were presumed to be phospholipases, we found that they are 5′-ssDNA exonucleases that break down TLR9 ligands. Mice deficient in both PLD3 and PLD4 died pre-weaning from an inflammatory disease with many similarities to primary hemophagocytic lymphohistiocytosis (HLH). The levels of IFN γ, IL-6, TNF α, IL-10 and ferritin were markedly elevated in the serum of Pld3−/−Pld4−/− mice. Low blood platelets, severe anemia, liver steatosis, and hemophagocytosis were evident in Pld3−/−Pld4−/− mice. The lethal inflammation in PLD3 and PLD4 deficient animals was only marginally improved by IFN γ deficiency, however inactivation of UNC93B1 rescues their survival, revealing excessive endosomal TLR signaling is responsible for driving the disease.

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Nemazee, David, Amanda L. Gavin, and Deli Huang. "PLD3 and PLD4 are single-stranded acid exonucleases that regulate endosomal nucleicacid sensing." Journal of Immunology 202, no. 1_Supplement (May 1, 2019): 178.6. http://dx.doi.org/10.4049/jimmunol.202.supp.178.6.

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Abstract Genome-wide association studies have linked the gene encoding phospholipase D3 (PLD3) to Alzheimer’s disease and have linked PLD4 to rheumatoid arthritis and systemic sclerosis. PLD3 and PLD4 are endolysosomal proteins that we recently discovered are nucleases. PLD4-deficient mice have an inflammatory disease, marked by elevated levels of interferon-γ (IFN-γ) and splenomegaly. These phenotypes are blocked in the absence of TLR9. PLD3−/− mice have a relatively benign phenotype. Mice deficient in both PLD3 and PLD4 developed lethal liver inflammation in early life, which was blocked on a Unc93b-3d/3d background. These data suggest that PLD3 and PLD4 enzymes play important roles in the regulation of endosomal TLR signaling.

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Nemazee, David, Linghang Peng, Tanya Blane, Deli Huang, and Amanda Gavin. "Cleavage of DNA and RNA by PLD3 and PLD4 limits autoinflammatory triggering by multiple sensors, including endolysosomal TLRs and a STING dependent sensing pathway." Journal of Immunology 208, no. 1_Supplement (May 1, 2022): 158.05. http://dx.doi.org/10.4049/jimmunol.208.supp.158.05.

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Abstract We have studied the biochemistry and genetics of Phospholipase D3 (PLD3) and PLD4 because polymorphisms of these proteins have been associated with several important inflammatory and autoimmune diseases, including rheumatoid arthritis, systemic sclerosis, systemic lupus erythematosus and Alzheimer’s disease. We found that both PLD3 and PLD4 are 5’ exonucleases able to degrade both ssDNA and ssRNA. Deficiency in PLD3, PLD4 or both results in a variety of inflammatory defects, with the most serious being lethal hemophagocytic lymphohistiocytosis (HLH) in double knockout mice. Pld3−/−Pld4−/− mice represent a unique spontaneous model of HLH apparently independent of microbes, whereas Pld4−/− mice develop a range of phenotypes depending upon genetic background ranging from macrophage activation syndrome to lupus like disease. Evidence will be presented showing that the diseases in these mice result from autorecognition of nucleic acids and can be reversed by mutation of nucleic acid sensing pathways. PLD3 and PLD4 tend to limit TLR9 recognition but have a more complex effect on recognition by TLR7 and TLR8. Unc93b13d/3dPld3−/−Pld4−/− mice spontaneously signal through STING suggesting that PLD3 and PLD4 also may regulate cytoplasmic nucleic acid sensing. Supported by NIH grants R01 AI142945 and R56AG070775

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SLAABY, Rita, Guangwei DU, Yelena M. ALTSHULLER, Michael A. FROHMAN, and Klaus SEEDORF. "Insulin-induced phospholipase D1 and phospholipase D2 activity in human embryonic kidney-293 cells mediated by the phospholipase Cγ and protein kinase Cα signalling cascade." Biochemical Journal 351, no. 3 (October 24, 2000): 613–19. http://dx.doi.org/10.1042/bj3510613.

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Phospholipase D (PLD)1 is quiescent in vitro and in vivo until stimulated by classical protein kinase C (PKC) isoforms, ADP-ribosylation factor or Rho family members. By contrast, PLD2 has high basal activity, and the mechanisms involved in agonist-induced activation of PLD2 are poorly understood. Using transiently transfected human embryonic kidney (HEK)-293 cells as a model system, we report in the present study that PLD2 overexpressed in HEK-293 cells exhibits regulatory properties similar to PLD1 when stimulated in response to insulin and phorbol ester. Co-expression of PLD1 or PLD2 with PKCα results in constitutive activation of both PLD isoforms, which cannot be further stimulated by insulin. Co-expression of PLD1 with phospholipase C (PLC)γ has the same effect, while co-expression of PLD2 with PLCγ allows PLD2 activity to be stimulated in an insulin-dependent manner. The PKC-specific inhibitors bisindolylmaleimide and Gö 6976 abolish insulin-induced PLD2 activation in HEK-293 cells co-expressing the insulin receptor, PLCγ and PLD2, confirming that not only PLD1, but PLD2 as well, is regulated in a PKC-dependent manner. Finally, we provide evidence that PKCα is constitutively associated with PLD2. In summary, we demonstrate that insulin treatment results in activation of both PLD1 and PLD2 in appropriate cell types when the appropriate upstream intermediate signalling components, i.e. PKCα and PLCγ, are expressed at sufficient levels.

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Suryadevara, Vidyani, Longshuang Huang, Seok-Jo Kim, Paul Cheresh, Mark Shaaya, Mounica Bandela, Panfeng Fu, et al. "Role of phospholipase D in bleomycin-induced mitochondrial reactive oxygen species generation, mitochondrial DNA damage, and pulmonary fibrosis." American Journal of Physiology-Lung Cellular and Molecular Physiology 317, no. 2 (August 1, 2019): L175—L187. http://dx.doi.org/10.1152/ajplung.00320.2018.

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Idiopathic pulmonary fibrosis (IPF) is a pernicious lung disease characterized by alveolar epithelial apoptosis, dysregulated repair of epithelial injury, scar formation, and respiratory failure. In this study, we identified phospholipase D (PLD)-generated phosphatidic acid (PA) signaling in the development of pulmonary fibrosis (PF). Of the PLD isoenzymes, the protein expression of PLD2, but not PLD1, was upregulated in lung tissues from IPF patients and bleomycin challenged mice. Both PLD1 ( Pld1−/−)- and PLD2 ( Pld2−/−)-deficient mice were protected against bleomycin-induced lung inflammation and fibrosis, thereby establishing the role of PLD in fibrogenesis. The role of PLD1 and PLD2 in bleomycin-induced lung epithelial injury was investigated by infecting bronchial airway epithelial cells (Beas2B) with catalytically inactive mutants of PLD ( hPLD1-K898R or mPld2-K758R) or downregulation of expression of PLD1 or PLD2 with siRNA. Bleomycin stimulated mitochondrial (mt) superoxide production, mtDNA damage, and apoptosis in Beas2B cells, which was attenuated by the catalytically inactive mutants of PLD or PLD2 siRNA. These results show a role for PLD1 and PLD2 in bleomycin-induced generation of mt reactive oxygen species, mt DNA damage, and apoptosis of lung epithelial cells in mice. Thus, PLD may be a novel therapeutic target in ameliorating experimental PF in mice.

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Ganesan, Ramya, Karen M. Henkels, Vasile I. Pavlov, Gregory L. Stahl, and Julian Gomez-Cambronero. "Myocardial Ischemia/Reperfusion injury is mediated by polymorphonuclear neutrophils through direct activation of Phospholipase D (PLD) and mTOR." Journal of Immunology 196, no. 1_Supplement (May 1, 2016): 188.6. http://dx.doi.org/10.4049/jimmunol.196.supp.188.6.

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Abstract During ischemia/reperfusion injury (I/RI), leukocytes release cytokines and exacerbate inflammation causing cardiac dysfunction, while neutrophils produce oxygen radicals that worsen the initial myocardial infarction. Phospholipase D is a cell membrane remodeling and signaling protein implicated in the pathology of I/RI. We analyzed I/RI by ejection fraction, infarct size and serum Troponin levels in wild-type, PLD1−/− and PLD2−/− mice. PLD-deficient mice or inhibition of PLD in WT mice protected against I/RI. Removing PLD2 yielded a slightly better outcome, suggesting PLD2 contributed more to the injury than PLD1, particularly at longer (>4 h) reperfusion times. Three cell signaling mechanisms were investigated: mTOR pathway, Aurora Kinase A and Cyclin-D3. Gene expression of the mTOR pathway was increased in response to I/RI in WT mice and abrogated in PLD-KO mice suggesting PLD augmented mTOR pathway during IR/I. PLD1−/− mice have lower expression of CCND3/Aurora Kinase A, while PLD2−/− mice expressed more phospho-CyclinD3. We detected neutrophil-associated Ly6G after adoptive transfer of bone marrow neutrophils during I/RI. Myocardial PMN accumulation was increased following I/R and PLD inhibitors abrogated PMN accumulation. Less myocardial PMN accumulation was observed in PLD-KO mice following IR/I. Adoptive transfer of fluorescently labeled PLD2−/− or PLD1−/−PMN into PLD1−/− or PLD2−/− mice, respectively, demonstrated that PLD1 containing (PLD2−/−) PMNs accumulated more significantly in the myocardium following I/RI. This study demonstrates for the first time the specific mechanistic contribution of mammalian PLD1 and PLD2 to MI/R injury in a murine model and their role in neutrophil infiltration.

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Lehman, Nicholas, Mauricio Di Fulvio, Nicholas McCray, Isabel Campos, Farnaz Tabatabaian, and Julian Gomez-Cambronero. "Phagocyte cell migration is mediated by phospholipases PLD1 and PLD2." Blood 108, no. 10 (November 15, 2006): 3564–72. http://dx.doi.org/10.1182/blood-2006-02-005959.

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Abstract We have investigated whether the signaling protein phospholipase D is implicated in leukocyte cell motility. Treating differentiated HL-60 cells with small interfering RNAs (siRNAs), to deplete endogenous expression of the PLD1 isoform, led to an abolishment of basal chemokinesis that could not be rescued with chemoattractants ENA-78, FMLP, and IL-8. Transient overexpression of PLD1 increased both chemokinesis and chemotaxis toward IL-8 and FMLP but not toward ENA-78. Chemokinesis was not mediated by the enzymatic activity of PLD1, but the chemotactic response was, because a lipase-inactive mutant (PLD1-K830R) negated all chemokine-induced potentiating actions and because IL-8 and FMLP increased activity in vitro. Gene expression silencing of the other mammalian isoform, PLD2, also led to cell migration arrest, whereas ENA-78 selectively increased endogenous PLD2 activity and chemotaxis of HL-60 cells overexpressing a myc-pcDNA-PLD2 construct. Thus, PLD1 is differentially activated by CXCR-1, whereas CXCR-2 (and possibly CXCR-1) mediates PLD2 activation. Finally, immunofluorescence microscopy showed that both isoforms were associated with cell polarity and directionality concomitantly with adhesion and F-actin polymerization in response to IL-8. These data represent the first demonstration of the involvement of PLD and its enzymatic activity toward chemokines in the key physiologic process of leukocyte migration.

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Lu, Wan, Chi Chung, Ray Chen, Li Huang, Li Lien, Chao Chang, Kuan Lin, and Joen Sheu. "An Antithrombotic Strategy by Targeting Phospholipase D in Human Platelets." Journal of Clinical Medicine 7, no. 11 (November 14, 2018): 440. http://dx.doi.org/10.3390/jcm7110440.

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Phospholipase D (PLD) is involved in many biological processes. PLD1 plays a crucial role in regulating the platelet activity of mice; however, the role of PLD in the platelet activation of humans remains unclear. Therefore, we investigated whether PLD is involved in the platelet activation of humans. Our data revealed that inhibition of PLD1 or PLD2 using pharmacological inhibitors effectively inhibits platelet aggregation in humans. However, previous studies have showed that PLD1 or PLD2 deletion did not affect mouse platelet aggregation in vitro, whereas only PLD1 deletion inhibited thrombus formation in vivo. Intriguingly, our data also showed that the pharmacological inhibition of PLD1 or PLD2 does not affect mouse platelet aggregation in vitro, whereas the inhibition of only PLD1 delayed thrombus formation in vivo. These findings indicate that PLD may play differential roles in humans and mice. In humans, PLD inhibition attenuates platelet activation, adhesion, spreading, and clot retraction. For the first time, we demonstrated that PLD1 and PLD2 are essential for platelet activation in humans, and PLD plays different roles in platelet function in humans and mice. Our findings also indicate that targeting PLD may provide a safe and alternative therapeutic approach for preventing thromboembolic disorders.

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Choi, Wahn Soo, Takaaki Hiragun, Jun Ho Lee, Young Mi Kim, Hyoung-Pyo Kim, Ahmed Chahdi, Erk Her, Jeung Whan Han, and Michael A. Beaven. "Activation of RBL-2H3 Mast Cells Is Dependent on Tyrosine Phosphorylation of Phospholipase D2 by Fyn and Fgr." Molecular and Cellular Biology 24, no. 16 (August 15, 2004): 6980–92. http://dx.doi.org/10.1128/mcb.24.16.6980-6992.2004.

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ABSTRACT Both phospholipase D1 (PLD1) and PLD2 regulate degranulation when RBL-2H3 cells are stimulated via the immunoglobulin E receptor, FcεRI. However, the activation mechanism for PLD2 is unclear. As reported here, PLD2 but not PLD1 is phosphorylated through the Src kinases, Fyn and Fgr, and this phosphorylation appears to regulate PLD2 activation and degranulation. For example, only hemagglutinin-tagged PLD2 was tyrosine phosphorylated in antigen-stimulated cells that had been made to express HA-PLD1 and HA-PLD2. This phosphorylation was blocked by a Src kinase inhibitor or by small interfering RNAs directed against Fyn and Fgr and was enhanced by overexpression of Fyn and Fgr but not by other Src kinases. The phosphorylation and activity of PLD2 were further enhanced by the tyrosine phosphatase inhibitor, Na3VO4. Mutation of PLD2 at tyrosines 11, 14, 165, or 470 partially impaired, and mutation of all tyrosines blocked, PLD2 phosphorylation and activation, although two of these mutations were detrimental to PLD2 function. PLD2 phosphorylation preceded degranulation, both events were equally sensitive to inhibition of Src kinase activity, and both were enhanced by coexpression of PLD2 and the Src kinases. The findings provide the first description of a mechanism for activation of PLD2 in a physiological setting and of a role for Fgr in FcεRI-mediated signaling.

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SARRI, Elisabeth, Raul PARDO, Amanda FENSOME-GREEN, and Shamshad COCKCROFT. "Endogenous phospholipase D2 localizes to the plasma membrane of RBL-2H3 mast cells and can be distinguished from ADP ribosylation factor-stimulated phospholipase D1 activity by its specific sensitivity to oleic acid." Biochemical Journal 369, no. 2 (January 15, 2003): 319–29. http://dx.doi.org/10.1042/bj20021347.

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We have examined the specificity of oleate as an activator of phospholipase D2 (PLD2) and whether it can be used to study PLD2 localization and its involvement in cell function. Oleate stimulates PLD activity in intact RBL-2H3 mast cells. Comparing PLD1- with PLD2-overexpressing cells, oleate enhanced PLD activity only in PLD2-overexpressing cells. Membranes were also sensitive to oleate and when membranes prepared from PLD1- and PLD2-overexpressing cells were examined, oleate further increased PLD activity only in membranes from PLD2-overexpressing cells. Overexpressed green fluorescent protein (GFP)-PLD2 fusion protein was localized at the plasma membrane and GFP-PLD1 was found in an intracellular vesicular compartment. Oleate was used to examine whether overexpressed PLD2 co-localized with endogenous PLD2. RBL-2H3 mast cell homogenates were fractionated on a linear sucrose gradient and analysed for both oleate-stimulated activity and ADP ribosylation factor 1-stimulated PLD1 activity. The oleate-stimulated activity co-localized with markers of the plasma membrane including the β-subunit of the Fc∊RI and linker for activation of T cells. Fractionation of homogenates from PLD2-overexpressing cells demonstrated that the overexpressed PLD2 fractionated in an identical location to the endogenous oleate-stimulated activity and this activity was greatly enhanced in comparison with control membranes. Examination of membranes prepared from COS-7, Jurkat and HL60 cells indicated a relationship between oleate-stimulated PLD2 activity and PLD2 immunoreactivity. We examined whether oleate could be used to activate secretion and membrane ruffling in adherent RBL-2H3 mast cells. Oleate did not stimulate secretion but did stimulate membrane ruffling, which was short-lived. We conclude that oleic acid is a selective activator of PLD2 and can be used for localization studies, but its use as an activator of PLD2 in intact cells to study function is limited due to toxicity.

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Natarajan, Viswanathan, William M. Scribner, Andrew J. Morris, Shukla Roy, Suryanarayana Vepa, Jianbin Yang, Raj Wadgaonkar, Sekhar P. M. Reddy, Joe G. N. Garcia, and Narasimham L. Parinandi. "Role of p38 MAP kinase in diperoxovanadate-induced phospholipase D activation in endothelial cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 281, no. 2 (August 1, 2001): L435—L449. http://dx.doi.org/10.1152/ajplung.2001.281.2.l435.

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We previously demonstrated that diperoxovanadate (DPV), a synthetic peroxovanadium compound and cell-permeable oxidant that acts as a protein tyrosine phosphatase inhibitor and insulinomimetic, increased phospholipase D (PLD) activation in endothelial cells (ECs). In this report, the regulation of DPV-induced PLD activation by mitogen-activated protein kinases (MAPKs) was investigated. DPV activated extracellular signal-regulated kinase, c-Jun NH2-terminal kinase (JNK), and p38 MAPK in a dose- and time-dependent fashion. Treatment of ECs with p38 MAPK inhibitors SB-203580 and SB-202190 or transient transfection with a p38 dominant negative mutant mitigated the PLD activation by DPV but not by phorbol ester. SB-202190 blocked DPV-mediated p38 MAPK activity as determined by activated transcription factor-2 phosphorylation. Immunoprecipitation of PLD from EC lysates with PLD1 and PLD2 antibodies revealed both PLD isoforms associated with p38 MAPK. Similarly, PLD1 and PLD2 were detected in p38 immunoprecipitates from control and DPV-challenged ECs. Binding assays demonstrated interaction of glutathione S-transferase-p38 fusion protein with PLD1 and PLD2. Both PLD1 and PLD2 were phosphorylated by p38 MAPK in vitro, and DPV increased phosphorylation of PLD1 and PLD2 in vivo. However, phosphorylation of PLD by p38 failed to affect PLD activity in vitro. These results provide evidence for p38 MAPK-mediated regulation of PLD in ECs.

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Freyberg, Zachary, Sylvain Bourgoin, and Dennis Shields. "Phospholipase D2 Is Localized to the Rims of the Golgi Apparatus in Mammalian Cells." Molecular Biology of the Cell 13, no. 11 (November 2002): 3930–42. http://dx.doi.org/10.1091/mbc.02-04-0059.

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Phospholipase D (PLD) hydrolyzes phosphatidylcholine to generate phosphatidic acid, a molecule known to have multiple physiological roles, including release of nascent secretory vesicles from thetrans-Golgi network. In mammalian cells two forms of the enzyme, PLD1 and PLD2, have been described. We recently demonstrated that PLD1 is localized to the Golgi apparatus, nuclei, and to a lesser extent, plasma membrane. Due to its low abundance, the intracellular localization of PLD2 has been characterized only indirectly through overexpression of chimeric proteins. Using antibodies specific to PLD2, together with immunofluorescence microscopy, herein we demonstrate that a significant fraction of endogenous PLD2 localized to the perinuclear Golgi region and was also distributed throughout cells in dense cytoplasmic puncta; a fraction of which colocalized with caveolin-1 and the plasma membrane. On treatment with brefeldin A, PLD2 translocated into the nucleus in a manner similar to PLD1, suggesting a potential role in nuclear signaling. Most significantly, cryoimmunogold electron microscopy demonstrated that in pituitary GH3 cells >90% of PLD2 present in the Golgi apparatus was localized to cisternal rims and peri-Golgi vesicles exclusively. The data are consistent with a model whereby PLD2 plays a role in Golgi vesicular transport.

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WANG, Lixin, Rhett CUMMINGS, Peter USATYUK, Andrew MORRIS, Kaikobad IRANI, and Viswanathan NATARAJAN. "Involvement of phospholipases D1 and D2 in sphingosine 1-phosphate-induced ERK (extracellular-signal-regulated kinase) activation and interleukin-8 secretion in human bronchial epithelial cells." Biochemical Journal 367, no. 3 (November 1, 2002): 751–60. http://dx.doi.org/10.1042/bj20020586.

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Sphingosine 1-phosphate (S1P), a metabolite of sphingomyelin degradation, stimulates interleukin-8 (IL-8) secretion in human bronchial epithelial (Beas-2B) cells. The molecular mechanisms regulating S1P-mediated IL-8 secretion are yet to be completely defined. Here we provide evidence that activation of phospholipases D1 and D2 (PLD1 and PLD2) by S1P regulates the phosphorylation of extracellular-signal-regulated kinase (ERK) and IL-8 secretion in Beas-2B cells. S1P, in a time- and dose-dependent manner, enhanced the threonine/tyrosine phosphorylation of ERK. The inhibition of S1P-induced ERK phosphorylation by pertussis toxin and PD 98059 indicated coupling of S1P receptors to Gi and the ERK signalling cascade respectively. Treatment of Beas-2B cells with butan-1-ol, but not butan-3-ol, abrogated the S1P-induced phosphorylation of Raf-1 and ERK, suggesting that PLD is involved in this activation. The roles of PLD1 and PLD2 in ERK activation and IL-8 secretion activated by S1P were investigated by infecting cells with adenoviral constructs of wild-type and catalytically inactive mutants of PLD1 and PLD2. Infection of Beas-2B cells with the wild-type constructs resulted in the activation of PLD1 and PLD2 by S1P and PMA. Also, the enhanced production of [32P]phosphatidic acid and [32P]phosphatidylbutanol in the presence of butan-1-ol and the increased phosphorylation of ERK by S1P were blocked by the catalytically inactive mutants hPLD1-K898R and mPLD2-K758R. Transient transfection of Beas-2B cells with human PLD1 and mouse PLD2 cDNAs potentiated S1P-mediated IL-8 secretion compared with vector controls. In addition, PD 98059 attenuated IL-8 secretion induced by S1P in a dose-dependent fashion. These results demonstrate that both PLD1 and PLD2 participate in S1P stimulation of ERK phosphorylation and IL-8 secretion in bronchial epithelial cells.

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Malcovati, Luca, Daniela Pietra, Matteo G. Della Porta, Andrea Pellagatti, Erica Travaglino, Emanuela Boveri, Anna Gallì, et al. "Differential Expression of Genes Related to JAK-STAT Pathway Activation or Megakaryocyte Differentiation/Maturation in CD34+ Cells from Patients with Refractory Anemia with Ringed Sideroblasts and Thrombocytosis (RARS-T)." Blood 110, no. 11 (November 16, 2007): 397. http://dx.doi.org/10.1182/blood.v110.11.397.397.

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Abstract A peculiar feature of the myelodysplastic syndrome (MDS) defined as refractory anemia with ringed sideroblasts (RARS) is that CD34+ cells have a distinct expression profile characterized by up-regulation of mitochondrial-related genes and, in particular, of those of heme synthesis, e.g., ALAS2 [Blood2006;108:337–45]. RARS-T is a poorly defined myelodysplastic/myeloproliferative variant of RARS. RARS-T patients may carry the JAK2 (V617F) mutation, and this might considerably affect gene expression. We did studies of JAK2 and MPL mutation analysis, and of gene expression profiling in 16 RARS-T patients. We employed a real time PCR-based allelic discrimination assay for the detection of JAK2 (V617F), and direct sequencing for the analysis of JAK2 exon 12 and MPL exon 10 mutations. The Affymetrix microarray technology (U133 Plus2.0 chips) was used for gene expression profiling of purified bone marrow CD34+ cells. Mutations of JAK2 and/or MPL were detected in granulocytes but not T-lymphocytes from 7/16 patients (44%). Five patients carried JAK2 (V617F), one patient had the JAK2 exon 12 E543-D544del, and the remaining patient had both JAK2 (V617F) and MPL (W515L) mutant alleles. Granulocytes carrying mutant alleles represented only a minor fraction of clonal granulocytes, as determined by X-chromosome inactivation patterns. By comparing gene expression profiles of CD34+ cells from 12 RARS and 6 RARS-T patients (4 of these latter carrying mutant JAK2 alleles), 255 genes were found to be differentially expressed. Within the 165 up-regulated genes, the most represented ones included genes related to transcription regulation, cell proliferation, and cytoskeleton organization. Within the 90 down-regulated genes, those related to cell cycle arrest and cell adhesion were the most recurrent ones. Forty-six genes were found to be differentially expressed in all 6 RARS-T cases, and 8 of these showed a relative expression ratio >2. In particular, CXCR4, a gene encoding a CXC chemokine receptor specific for SDF-1 and reported to be down-regulated in primary myelofibrosis, was markedly down-regulated in RARS-T patients. JCTSG (encoding cathepsin) and JLTF (encoding lactoferrin and inhibited by STAT5 activation) were also markedly down-regulated. A significant up-regulation of TNRC15, a gene involved in the signal transduction by insulin-like growth factor (IGF-I), was observed. Finally, a few genes involved in cytoskeleton organization and megakaryocyte differentiation/maturation (like CDC2L5, ARHGAP12, and PLDN) were found to be differentially expressed. Thus, in refractory anemia with ringed sideroblasts, clonal hematopoietic cells may acquire not only JAK2 (V617F), but also of JAK2 exon 12 and MPL exon 10 mutations. The occurrence of JAK2 and MPL mutations, and possibly of additional ones, results in CD34+ cell expression profiles consistent with activation of the JAK-STAT pathway and enhancement of megakaryocytopoiesis.

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Suryadevara, V., T. Royston, E. Berdyshev, L. Huang, V. Natarajan, and A. Tager. "ID: 112: ROLE OF PHOSPHOLIPASE D IN IDIOPATHIC PULMONARY FIBROSIS." Journal of Investigative Medicine 64, no. 4 (March 22, 2016): 964.1–964. http://dx.doi.org/10.1136/jim-2016-000120.108.

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Idiopathic pulmonary fibrosis (IPF) is a deadly interstitial disease that leads to scarring and fibrosis of the lung tissue. In pulmonary fibrosis, there is injury and denudation of the alveolar epithelium, which further leads to activation of fibroblasts which differentiate into myofibroblasts. This includes several mechanisms including epithelial to mesenchymal transition (EMT). In this study, we investigated the role of phospholipase D (PLD) in IPF and also its underlying mechanism like EMT and fibroblast proliferation and differentiation. An in vivo murine model of bleomycin-induced pulmonary fibrosis (PF) and in vitro models of murine alveolar type-II epithelial cells (MLE-12) and human lung fibroblasts were used. C57BL/6 and genetically engineered PLD2−/− mice were intratracheally challenged with bleomycin (1.5 U/kg animal) for 14 days and markers of inflammation, EMT and fibrosis were determined. MLE-12 cells were treated with specific PLD1 or PLD2 inhibitors prior to bleomycin (10 mU/ml) challenge, and the role of PLD in EMT and apoptosis of alveolar epithelial cells was studied. Human lung fibroblasts were serum-starved (3h), pretreated with PLD1 or PLD2 inhibitors, and the effect of TGF-β (5 ng/ml) on differentiation of lung fibroblast to myofibroblast was determined. Intra-tracheal instillation of bleomycin in the mice for 14 days leads to the progression of fibrosis in the lung. The lung tissues of the bleomycin treated mice were found to have increased PLD2 protein expression, myofibroblast markers like α-SMA, fibronectin, mesenchymal markers like vimentin, inflammatory cytokines and collagen. Genetic deletion of PLD2 in mice attenuated bleomycin-induced lung inflammation and pulmonary fibrosis. In vitro, MLE-12 cells pretreated with either PLD1 or PLD2 inhibitor did not show a profound reduction either in apoptosis or the expression of transcription factors such as SNAIL, and other markers of EMT. However, MLE-12 cells pretreated with both PLD1 (250 nM) and PLD2 (500 nM) inhibitors were resistant to bleomycin-induced apoptosis, and exhibited reduced expression of SNAIL and mesenchymal markers. On the contrary, human lung fibroblasts pretreated with PLD1 and PLD2 inhibitors showed increased fibroblast to myofibroblast differentiation mediated by TGF-β. The present study suggests a role for PLD2 in bleomycin-induced PF. In vitro, inhibition of both PLD1 and PLD2 was necessary to attenuate bleomycin-induced EMT in epithelial cells and TGF-β mediated differentiation of fibroblasts to myofibroblasts. The in vivo and in vitro results identify the mechanism by which PLD regualtes PF and suggest PLD as a potential therapeutic target in pulmonary fibrosis. This work was supported by National Institutes of Health grant P01 HL98050 to VN.

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Shirey, Ryan J., Lewis D. Turner, Luke L. Lairson, and Kim D. Janda. "Modulators of immunoregulatory exonucleases PLD3 and PLD4 identified by high-throughput screen." Bioorganic & Medicinal Chemistry Letters 49 (October 2021): 128293. http://dx.doi.org/10.1016/j.bmcl.2021.128293.

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Siddiqi, Abdur R., Geraldine E. Srajer, and Christina C. Leslie. "Regulation of human PLD1 and PLD2 by calcium and protein kinase C." Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 1497, no. 1 (June 2000): 103–14. http://dx.doi.org/10.1016/s0167-4889(00)00049-5.

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REDINA, Olga E., and Michael A. FROHMAN. "Organization and alternative splicing of the murine phospholipase D2 gene." Biochemical Journal 331, no. 3 (May 1, 1998): 845–51. http://dx.doi.org/10.1042/bj3310845.

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Phospholipase D (PLD) catalyses the hydrolysis of phosphatidylcholine, generating phosphatidic acid and choline. Mammalian PLD activity derives from a family of membrane-associated enzymes that are activated by a wide variety of signal transduction events. cDNA species encoding human, mouse and rat PLD1 and PLD2 have recently been reported. In this study we undertook to determine the organization of the mouse PLD2 gene. We report that the gene spans 17.1 kb and contains 25 exons. Mouse PLD2 is notable for a relatively GC-rich and large 5´ untranslated region. Proximal promoter sequences upstream of the first exon contain several consensus SP1 sequences (GGGCGG) but lack TATA and CAAT boxes. Finally, alternatively spliced cDNA species identified for PLD1 and PLD2 are discussed in the context of the PLD2 genomic organization.

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Borsi, Katharina. "The 'Hobrecht plan' and the emergence of the urban." SAJ - Serbian Architectural Journal 10, no. 1 (2018): 47–58. http://dx.doi.org/10.5937/saj1801047b.

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James Hobrecht's Berlin extension plan of 1862 and its architectural component, the Berlin block, continue to define Berlin's current urban structure. The urban structure which these graphic documents helped to deliver persisted despite being rejected through much of the twentieth century. Despite its significance, research on the Hobrecht plan is scarce, and many interpret the plan through its historical context. By contrast, this paper argues that the Berlin block cannot be reduced to representations through its urban plan and architectural component. Instead, they provide a specific urban rationality that poses the question: What is a city? Françoise Choay identified a new urban figure in Ildefonso Cerdá's urban theories, a figure that comes to underlie subsequent theorisations of the urban. The paper argues that the Hobrecht plan and its component block can be read as the graphic and spatial counterpart to Choay's textual figure of the urban.

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Noble, Amanda R., Karen Hogg, Rakesh Suman, Daniel M. Berney, Sylvain Bourgoin, Norman J. Maitland, and Martin G. Rumsby. "Phospholipase D2 in prostate cancer: protein expression changes with Gleason score." British Journal of Cancer 121, no. 12 (November 1, 2019): 1016–26. http://dx.doi.org/10.1038/s41416-019-0610-7.

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Abstract Background Phospholipases D1 and D2 (PLD1/2) are implicated in tumorigenesis through their generation of the signalling lipid phosphatidic acid and its downstream effects. Inhibition of PLD1 blocks prostate cell growth and colony formation. Here a role for PLD2 in prostate cancer (PCa), the major cancer of men in the western world, is examined. Methods PLD2 expression was analysed by immunohistochemistry and western blotting. The effects of PLD2 inhibition on PCa cell viability and cell motility were measured using MTS, colony forming and wound-healing assays. Results PLD2 protein is expressed about equally in luminal and basal prostate epithelial cells. In cells from different Gleason-scored PCa tissue PLD2 protein expression is generally higher than in non-tumorigenic cells and increases in PCa tissue scored Gleason 6–8. PLD2 protein is detected in the cytosol and nucleus and had a punctate appearance. In BPH tissue stromal cells as well as basal and luminal cells express PLD2. PLD2 protein co-expresses with chromogranin A in castrate-resistant PCa tissue. PLD2 inhibition reduces PCa cell viability, colony forming ability and directional cell movement. Conclusions PLD2 expression correlates with increasing Gleason score to GS8. PLD2 inhibition has the potential to reduce PCa progression.

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Hitomi, Tomohiro, Juan Zhang, Liliana M. Nicoletti, Ana Cristina G. Grodzki, Maria C. Jamur, Constance Oliver, and Reuben P. Siraganian. "Phospholipase D1 regulates high-affinity IgE receptor-induced mast cell degranulation." Blood 104, no. 13 (December 15, 2004): 4122–28. http://dx.doi.org/10.1182/blood-2004-06-2091.

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Abstract To investigate the role of phospholipase D (PLD) in FcϵRI signaling, the wild-type or the catalytically inactive forms of PLD1 or PLD2 were stably overexpressed in RBL-2H3 mast cells. FcϵRI stimulation resulted in the activation of both PLD1 and PLD2. However, PLD1 was the source of most of the receptor-induced PLD activity. There was enhanced FcϵRI-induced degranulation only in cells that overexpressed the catalytically inactive PLD1. This dominant-negative PLD1 enhanced FcϵRI-induced tyrosine phosphorylations of early signaling molecules such as the receptor subunits, Syk and phospholipase C-γ which resulted in faster release of Ca2+ from intracellular sources. Therefore, PLD1 negatively regulates signals upstream of the Ca2+ response. However, FcϵRI-induced PLD activation required Syk and was downstream of the Ca2+response, suggesting that basal PLD1 activity rather than that activated by cell stimulation controlled these early signaling events. Dominant-negative PLD1 reduced the basal phosphatidic acid formation in unstimulated cells, which was accompanied by an increase in FcϵRI within the lipid rafts. These results indicate that constitutive basal PLD1 activity by regulating phosphatidic acid formation controls the early signals initiated by FcϵRI aggregation that lead to mast cell degranulation. (Blood. 2004;104:4122-4128)

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Du, Guangwei, Ping Huang, Bruce T. Liang, and Michael A. Frohman. "Phospholipase D2 Localizes to the Plasma Membrane and Regulates Angiotensin II Receptor Endocytosis." Molecular Biology of the Cell 15, no. 3 (March 2004): 1024–30. http://dx.doi.org/10.1091/mbc.e03-09-0673.

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Phospholipase D (PLD) is a key facilitator of multiple types of membrane vesicle trafficking events. Two PLD isoforms, PLD1 and PLD2, exist in mammals. Initial studies based on overexpression studies suggested that in resting cells, human PLD1 localized primarily to the Golgi and perinuclear vesicles in multiple cell types. In contrast, overexpressed mouse PLD2 was observed to localize primarily to the plasma membrane, although internalization on membrane vesicles was observed subsequent to serum stimulation. A recent report has suggested that the assignment of PLD2 to the plasma membrane is in error, because the endogenous isoform in rat secretory cells was imaged and found to be present primarily in the Golgi apparatus. We have reexamined this issue by using a monoclonal antibody specific for mouse PLD2, and find, as reported initially using overexpression studies, that endogenous mouse PLD2 is detected most readily at the plasma membrane in multiple cell types. In addition, we report that mouse, rat, and human PLD2 when overexpressed all similarly localize to the plasma membrane in cell lines from all three species. Finally, studies conducted using overexpression of wild-type active or dominant-negative isoforms of PLD2 and RNA interference-mediated targeting of PLD2 suggest that PLD2 functions at the plasma membrane to facilitate endocytosis of the angiotensin II type 1 receptor.

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Yang, Zhiwei, Laureano D. Asico, Peiying Yu, Zheng Wang, John E. Jones, Ren-kui Bai, David R. Sibley, Robin A. Felder, and Pedro A. Jose. "D5 dopamine receptor regulation of phospholipase D." American Journal of Physiology-Heart and Circulatory Physiology 288, no. 1 (January 2005): H55—H61. http://dx.doi.org/10.1152/ajpheart.00627.2004.

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D1-like receptors have been reported to decrease oxidative stress in vascular smooth muscle cells by decreasing phospholipase D (PLD) activity. However, the PLD isoform regulated by D1-like receptors (D1 or D5) and whether abnormal regulation of PLD by D1-like receptors plays a role in the pathogenesis of hypertension are unknown. The hypothesis that the D5 receptor is the D1-like receptor that inhibits PLD activity and serves to regulate blood pressure was tested using D5 receptor mutant mice (D5−/−). We found that in the mouse kidney, PLD2, like the D5 receptor, is mainly expressed in renal brush-border membranes, whereas PLD1 is mainly expressed in renal vessels with faint staining in brush-border membranes and collecting ducts. Total renal PLD activity is increased in D5−/− mice relative to congenic D5 wild-type (D5+/+) mice. PLD2, but not PLD1, expression is greater in D5−/− than in D5+/+ mice. The D5 receptor agonist fenoldopam decreases PLD2, but not PLD1, expression and activity in human embryonic kidney-293 cells heterologously expressing the human D5 receptor, effects that are blocked by the D5 receptor antagonist SCH-23390. These studies show that the D5 receptor regulates PLD2 activity and expression. The hypertension in the D5−/− mice is associated with increased PLD expression and activity. Impaired D5 receptor regulation of PLD2 may play a role in the pathogenesis of hypertension.

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Melendez, Alirio J., Luce Bruetschy, R. Andres Floto, Margaret M. Harnett, and Janet M. Allen. "Functional coupling of FcγRI to nicotinamide adenine dinucleotide phosphate (reduced form) oxidative burst and immune complex trafficking requires the activation of phospholipase D1." Blood 98, no. 12 (December 1, 2001): 3421–28. http://dx.doi.org/10.1182/blood.v98.12.3421.

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Abstract Immunoglobulin G (IgG) receptors (FcγRs) on myeloid cells are responsible for the internalization of immune complexes. Activation of the oxidase burst is an important component of the integrated cellular response mediated by Fc receptors. Previous work has demonstrated that, in interferon-γ–primed U937 cells, the high-affinity receptor for IgG, FcγRI, is coupled to a novel intracellular signaling pathway that involves the sequential activation of phospholipase D (PLD), sphingosine kinase, and calcium transients. Here, it is shown that both known PLD isozymes, PLD1 and PLD2, were present in these cells. With the use of antisense oligonucleotides to specifically reduce the expression of either isozyme, PLD1, but not PLD2, was found to be coupled to FcγRI activation and be required to mediate receptor activation of sphingosine kinase and calcium transients. In addition, coupling of FcγRI to activation of the nicotinamide adenine dinucleotide phosphate (reduced form) (NADPH) oxidase burst was inhibited by pretreating cells with 0.3% butan-1-ol, indicating an absolute requirement for PLD. Furthermore, use of antisense oligonucleotides to reduce expression of PLD1 or PLD2 demonstrated that PLD1 is required to couple FcγRI to the activation of NADPH oxidase and trafficking of internalized immune complexes for degradation. These studies demonstrate the critical role of PLD1 in the intracellular signaling cascades initiated by FcγRI and its functional role in coordinating the response to antigen-antibody complexes.

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Steed, Paul M., Kirk L. Clark, William C. Boyar, and Daniel J. Lasala. "Characterization of human PLD2 and the analysis of PLD isoform splice variants." FASEB Journal 12, no. 13 (October 1998): 1309–17. http://dx.doi.org/10.1096/fasebj.12.13.1309.

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Gavin, Amanda L., Deli Huang, Christoph Huber, Annica Mårtensson, Virginie Tardif, Patrick D. Skog, Tanya R. Blane, et al. "PLD3 and PLD4 are single-stranded acid exonucleases that regulate endosomal nucleic-acid sensing." Nature Immunology 19, no. 9 (August 13, 2018): 942–53. http://dx.doi.org/10.1038/s41590-018-0179-y.

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Qin, Chunbo, Cunxi Wang, and Xuemin Wang. "Kinetic Analysis ofArabidopsisPhospholipase Dδ." Journal of Biological Chemistry 277, no. 51 (October 22, 2002): 49685–90. http://dx.doi.org/10.1074/jbc.m209598200.

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Phospholipase D (PLD) is a major plant phospholipase family involved in many cellular processes such as signal transduction, membrane remodeling, and lipid degradation. Five classes of PLDs have been identified inArabidopsis thaliana, and Ca2+and polyphosphoinositides have been suggested as key regulators for these enzymes. To investigate the catalysis and regulation mechanism of individual PLDs, surface-dilution kinetics studies were carried out on the newly identified PLDδ fromArabidopsis. PLDδ activity was dependent on both bulk concentration and surface concentration of substrate phospholipids in the Triton X-100/phospholipid mixed micelles.Vmax,KsA, andKmBvalues for PLDδ toward phosphatidylcholine or phosphatidylethanolamine were determined; phosphatidylethanolamine was the preferred substrate. PLDδ activity was stimulated greatly by phosphatidylinositol 4,5-bisphosphate (PIP2). Maximal activation was observed at a PIP2molar ratio around 0.01. Kinetic analysis indicates that PIP2activates PLD by promoting substrate binding to the enzyme, without altering the bulk binding of the enzyme to the micelle surface. Ca2+is required for PLDδ activity, and it significantly decreased the interfacial Michaelis constantKmB. This indicates that Ca2+activates PLD by promoting the binding of phospholipid substrate to the catalytic site of the enzyme.

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Shen, Yingjie, Lizhong Xu, and David A. Foster. "Role for Phospholipase D in Receptor-Mediated Endocytosis." Molecular and Cellular Biology 21, no. 2 (January 15, 2001): 595–602. http://dx.doi.org/10.1128/mcb.21.2.595-602.2001.

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ABSTRACT In response to epidermal growth factor (EGF), the EGF receptor is endocytosed and degraded. A substantial lag period exists between endocytosis and degradation, suggesting that endocytosis is more than a simple negative feedback. Phospholipase D (PLD), which has been implicated in vesicle formation in the Golgi, is activated in response to EGF and other growth factors. We report here that EGF receptor endocytosis is dependent upon PLD and the PLD1 regulators, protein kinase C α and RalA. EGF-induced receptor degradation is accelerated by overexpression of either wild-type PLD1 or PLD2 and retarded by overexpression of catalytically inactive mutants of either PLD1 or PLD2. EGF-induced activation of mitogen-activated protein kinase, which is dependent upon receptor endocytosis, is also dependent upon PLD. These data suggest a role for PLD in signaling that facilitates receptor endocytosis.

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LOCATI, Massimo, Elena RIBOLDI, Raffaella BONECCHI, Pietro TRANSIDICO, Sergio BERNASCONI, Bodduluri HARIBABU, Andrew J. MORRIS, Alberto MANTOVANI, and Silvano SOZZANI. "Selective induction of phospholipase D1 in pathogen-activated human monocytes." Biochemical Journal 358, no. 1 (August 8, 2001): 119–25. http://dx.doi.org/10.1042/bj3580119.

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Phospholipase D (PLD) activation is part of the complex signalling cascade induced during phagocyte activation. Two PLD isoforms have been cloned, but their role in phagocyte functions is still poorly defined. We report that resting fresh circulating human monocytes expressed PLD1. PLD1 protein expression was rapidly down-regulated during cell culture. Lipopolysaccharide and pathogen-derived agonists (Candida albicans, arabinoside-terminated lipoarabinomannan and Gram-positive bacteria, but not mannose-capped lipoarabinomannan or double-stranded RNA) strongly induced PLD1 expression at both the mRNA and protein levels. Pro-inflammatory cytokines [interleukin (IL)-1β and tumour necrosis factor α] had only a weak effect, whereas immune cytokines (IL-6 and interferon γ), anti-inflammatory cytokines (IL-13 and IL-10) and chemoattractants (fMet-Leu-Phe and macrophage chemoattractant protein 1) were inactive. None of the agonists tested induced significant changes in the basal expression of PLD2 mRNA. Consistent with PLD1 up-regulation was the observation that PLD enzymic activity was higher in monocytes treated with active-pathogen-derived agonists than in control cells, when stimulated with PMA or with chemotactic agonists (fMet-Leu-Phe and C5a). Thus PLD2 seems to be a constitutive enzyme in circulating monocytes. Conversely, PLD1 is an inducible protein, rapidly regulated during culture conditions and selectively induced during cell activation. Therefore PLD1 might have a relevant role in immune responses against pathogens and in chronic inflammation.

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Wang, X., C. Wang, Y. Sang, L. Zheng, and C. Qin. "Determining functions of multiple phospholipase Ds in stress response of Arabidopsis." Biochemical Society Transactions 28, no. 6 (December 1, 2000): 813–16. http://dx.doi.org/10.1042/bst0280813.

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Phospholipase D (PLD) is encoded by a multiple gene family, and several PLDs from Arabidopsis have been characterized at the molecular biological and biochemical levels. PLDα is the most abundant plant PLD and exhibits a number of different biochemical properties to the other isoforms. The other PLDs have many overlapping catalytic properties but display some unique patterns of expression during development and in response to stress cues. Accumulating data indicate that different PLDs have multiple and different roles in plant responses to stress.

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K.K. Suresh, K. K. Suresh, and M. Kavithamani M. Kavithamani. "Selection of Skip Lot Sampling Plan V with Multiple Repetitive Group Sampling Plan As Reference Plan Through Minimum Angle Criteria." International Journal of Scientific Research 2, no. 10 (June 1, 2012): 1–3. http://dx.doi.org/10.15373/22778179/oct2013/135.

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Journal articles on the topic 'PLDN'

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