Journal articles on the topic 'NPC1a'
To see the other types of publications on this topic, follow the link: NPC1a.
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 'NPC1a.'
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
Phillips, S. E., E. A. Woodruff, P. Liang, M. Patten, and K. Broadie. "Neuronal Loss of Drosophila NPC1a Causes Cholesterol Aggregation and Age-Progressive Neurodegeneration." Journal of Neuroscience 28, no. 26 (June 25, 2008): 6569–82. http://dx.doi.org/10.1523/jneurosci.5529-07.2008.
Full text
2
Bialistoky, Tzofia, Diane Manry, Peyton Smith, Christopher Ng, Yunah Kim, Sol Zamir, Victoria Moyal, et al. "Functional analysis of Niemann-Pick disease type C family protein, NPC1a, in Drosophila melanogaster." Development 146, no. 10 (May 15, 2019): dev168427. http://dx.doi.org/10.1242/dev.168427.
Full text
3
Antipova, Veronica, Lisa-Marie Steinhoff, Carsten Holzmann, Arndt Rolfs, Carlos Junior Hempel, Martin Witt, and Andreas Wree. "Organ Weights in NPC1 Mutant Mice Partly Normalized by Various Pharmacological Treatment Approaches." International Journal of Molecular Sciences 24, no. 1 (December 29, 2022): 573. http://dx.doi.org/10.3390/ijms24010573.
Full textAbstract:
Niemann-Pick Type C1 (NPC1, MIM 257220) is a rare, progressive, lethal, inherited autosomal-recessive endolysosomal storage disease caused by mutations in the NPC1 leading to intracellular lipid storage. We analyzed mostly not jet known alterations of the weights of 14 different organs in the BALB/cNctr-Npc1m1N/-J Jackson Npc1 mice in female and male Npc1+/+ and Npc1−/− mice under various treatment strategies. Mice were treated with (i) no therapy, (ii) vehicle injection, (iii) a combination of miglustat, allopregnanolone, and 2-hydroxypropyl-ß-cyclodextrin (HPßCD), (iv) miglustat, and (v) HPßCD alone starting at P7 and repeated weekly throughout life. The 12 respective male and female wild-type mice groups were evaluated in parallel. In total, 351 mice (176 Npc1+/+, 175 Npc1−/−) were dissected at P65. In both sexes, the body weights of None and Sham Npc1−/− mice were lower than those of respective Npc1+/+ mice. The influence of the Npc1 mutation and/or sex on the weights of various organs, however, differed considerably. In males, Npc1+/+ and Npc1−/− mice had comparable absolute weights of lungs, spleen, and adrenal glands. In Npc1−/− mice, smaller weights of hearts, livers, kidneys, testes, vesicular, and scent glands were found. In female Npc1−/− mice, ovaries, and uteri were significantly smaller. In Npc1−/− mice, relative organ weights, i.e., normalized with body weights, were sex-specifically altered to different extents by the different therapies. The combination of miglustat, allopregnanolone, and the sterol chelator HPßCD partly normalized the weights of more organs than miglustat or HPßCD mono-therapies.
4
Ko, Dennis C., Michael D. Gordon, Janet Y. Jin, and Matthew P. Scott. "Dynamic Movements of Organelles Containing Niemann-Pick C1 Protein: NPC1 Involvement in Late Endocytic Events." Molecular Biology of the Cell 12, no. 3 (March 2001): 601–14. http://dx.doi.org/10.1091/mbc.12.3.601.
Full textAbstract:
People homozygous for mutations in the Niemann-Pick type C1 (NPC1) gene have physiological defects, including excess accumulation of intracellular cholesterol and other lipids, that lead to drastic neural and liver degeneration. The NPC1 multipass transmembrane protein is resident in late endosomes and lysosomes, but its functions are unknown. We find that organelles containing functional NPC1-fluorescent protein fusions undergo dramatic movements, some in association with extending strands of endoplasmic reticulum. InNPC1 mutant cells the NPC1-bearing organelles that normally move at high speed between perinuclear regions and the periphery of the cell are largely absent. Pulse-chase experiments with dialkylindocarbocyanine low-density lipoprotein showed that NPC1 organelles function late in the endocytic pathway; NPC1 protein may aid the partitioning of endocytic and lysosomal compartments. The close connection between NPC1 and the drug U18666A, which causes NPC1-like organelle defects, was established by rescuing drug-treated cells with overproduced NPC1. U18666A inhibits outward movements of NPC1 organelles, trapping membranes and cholesterol in perinuclear organelles similar to those in NPC1 mutant cells, even when cells are grown in lipoprotein-depleted serum. We conclude that NPC1 protein promotes the creation and/or movement of particular late endosomes, which rapidly transport materials to and from the cell periphery.
5
Cawley, Niamh X., Anna T. Lyons, Daniel Abebe, Rachel Luke, Julia Yerger, Rebecca Telese, Christopher A. Wassif, Joan E. Bailey-Wilson, and Forbes D. Porter. "Complex N-Linked Glycosylation: A Potential Modifier of Niemann–Pick Disease, Type C1 Pathology." International Journal of Molecular Sciences 23, no. 9 (May 3, 2022): 5082. http://dx.doi.org/10.3390/ijms23095082.
Full textAbstract:
Complex asparagine-linked glycosylation plays key roles in cellular functions, including cellular signaling, protein stability, and immune response. Previously, we characterized the appearance of a complex asparagine-linked glycosylated form of lysosome-associated membrane protein 1 (LAMP1) in the cerebellum of Npc1−/− mice. This LAMP1 form was found on activated microglia, and its appearance correlated both spatially and temporally with cerebellar Purkinje neuron loss. To test the importance of complex asparagine-linked glycosylation in NPC1 pathology, we generated NPC1 knock-out mice deficient in MGAT5, a key Golgi-resident glycosyl transferase involved in complex asparagine-linked glycosylation. Our results show that Mgat5−/−:Npc1−/− mice were smaller than Mgat5+/+:Npc1−/− mice, and exhibited earlier NPC1 disease onset and reduced lifespan. Western blot and lectin binding analyses of cerebellar extracts confirmed the reduction in complex asparagine-linked glycosylation, and the absence of the hyper-glycosylated LAMP1 previously observed. Western blot analysis of cerebellar extracts demonstrated reduced calbindin staining in Mgat5−/−:Npc1−/− mice compared to Mgat5+/+:Npc1−/− mutant mice, and immunofluorescent staining of cerebellar sections indicated decreased levels of Purkinje neurons and increased astrogliosis in Mgat5−/−:Npc1−/− mice. Our results suggest that reduced asparagine-linked glycosylation increases NPC1 disease severity in mice, and leads to the hypothesis that mutations in genes involved in asparagine-linked glycosylation may contribute to disease severity progression in individuals with NPC1. To examine this with respect to MGAT5, we analyzed 111 NPC1 patients for two MGAT5 SNPs associated with multiple sclerosis; however, we did not identify an association with NPC1 phenotypic severity.
6
Dardis, Andrea, Stefania Zampieri, Cinzia Gellera, Rosalba Carrozzo, Silvia Cattarossi, Paolo Peruzzo, Rosalia Dariol, et al. "Molecular Genetics of Niemann–Pick Type C Disease in Italy: An Update on 105 Patients and Description of 18 NPC1 Novel Variants." Journal of Clinical Medicine 9, no. 3 (March 3, 2020): 679. http://dx.doi.org/10.3390/jcm9030679.
Full textAbstract:
Niemann-Pick type C (NPC) disease is an autosomal recessive lysosomal storage disorder caused by mutations in NPC1 or NPC2 genes. In 2009, the molecular characterization of 44 NPC Italian patients has been published. Here, we present an update of the genetic findings in 105 Italian NPC patients belonging to 83 unrelated families (77 NPC1 and 6 NPC2). NPC1 and NPC2 genes were studied following an algorithm recently published. Eighty-four different NPC1 and five NPC2 alleles were identified. Only two NPC1 alleles remained non detected. Sixty-two percent of NPC1 alleles were due to missense variants. The most frequent NPC1 mutation was the p.F284Lfs*26 (5.8% of the alleles). All NPC2 mutations were found in the homozygous state, and all but one was severe. Among newly diagnosed patients, 18 novel NPC1 mutations were identified. The pathogenic nature of 7/9 missense alleles and 3/4 intronic variants was confirmed by filipin staining and NPC1 protein analysis or mRNA expression in patient’s fibroblasts. Taken together, our previous published data and new results provide an overall picture of the molecular characteristics of NPC patients diagnosed so far in Italy.
7
Castillo, Joseph J., David Jelinek, Hao Wei, Nicholas P. Gannon, Roger A. Vaughan, L. John Horwood, F. John Meaney, et al. "The Niemann-Pick C1 gene interacts with a high-fat diet to promote weight gain through differential regulation of central energy metabolism pathways." American Journal of Physiology-Endocrinology and Metabolism 313, no. 2 (August 1, 2017): E183—E194. http://dx.doi.org/10.1152/ajpendo.00369.2016.
Full textAbstract:
A genome-wide association study (GWAS) reported that common variation in the human Niemann-Pick C1 gene ( NPC1) is associated with morbid adult obesity. This study was confirmed using our BALB/cJ Npc1 mouse model, whereby heterozygous mice ( Npc1+/−) with decreased gene dosage were susceptible to weight gain when fed a high-fat diet (HFD) compared with homozygous normal mice ( Npc1+/+) fed the same diet. The objective for our current study was to validate this Npc1 gene-diet interaction using statistical modeling with fitted growth trajectories, conduct body weight analyses for different measures, and define the physiological basis responsible for weight gain. Metabolic phenotype analysis indicated no significant difference between Npc1+/+ and Npc1+/− mice fed a HFD for food and water intake, oxygen consumption, carbon dioxide production, locomotor activity, adaptive thermogenesis, and intestinal lipid absorption. However, the livers from Npc1+/− mice had significantly increased amounts of mature sterol regulatory element-binding protein-1 (SREBP-1) and increased expression of SREBP-1 target genes that regulate glycolysis and lipogenesis with an accumulation of triacylglycerol and cholesterol. Moreover, white adipose tissue from Npc1+/− mice had significantly decreased amounts of phosphorylated hormone-sensitive lipase with decreased triacylglycerol lipolysis. Consistent with these results, cellular energy metabolism studies indicated that Npc1+/− fibroblasts had significantly increased glycolysis and lipogenesis, in addition to significantly decreased substrate (glucose and endogenous fatty acid) oxidative metabolism with an accumulation of triacylglycerol and cholesterol. In conclusion, these studies demonstrate that the Npc1 gene interacts with a HFD to promote weight gain through differential regulation of central energy metabolism pathways.
8
Li, Xiaochun, Piyali Saha, Jian Li, Günter Blobel, and Suzanne R. Pfeffer. "Clues to the mechanism of cholesterol transfer from the structure of NPC1 middle lumenal domain bound to NPC2." Proceedings of the National Academy of Sciences 113, no. 36 (August 22, 2016): 10079–84. http://dx.doi.org/10.1073/pnas.1611956113.
Full textAbstract:
Export of LDL-derived cholesterol from lysosomes requires the cooperation of the integral membrane protein Niemann–Pick C1 (NPC1) and a soluble protein, Niemann–Pick C2 (NPC2). Mutations in the genes encoding these proteins lead to Niemann–Pick disease type C (NPC). NPC2 binds to NPC1’s second (middle), lumenally oriented domain (MLD) and transfers cholesterol to NPC1’s N-terminal domain (NTD). Here, we report the 2.4-Å resolution crystal structure of a complex of human NPC1–MLD and NPC2 bearing bound cholesterol-3-O-sulfate. NPC1–MLD uses two protruding loops to bind NPC2, analogous to its interaction with the primed Ebola virus glycoprotein. Docking of the NPC1–NPC2 complex onto the full-length NPC1 structure reveals a direct cholesterol transfer tunnel between NPC2 and NTD cholesterol binding pockets, supporting the “hydrophobic hand-off” cholesterol transfer model.
9
Meneses-Salas, Elsa, Ana García-Melero, Patricia Blanco-Muñoz, Jaimy Jose, Marie-Sophie Brenner, Albert Lu, Francesc Tebar, Thomas Grewal, Carles Rentero, and Carlos Enrich. "Selective Degradation Permits a Feedback Loop Controlling Annexin A6 and Cholesterol Levels in Endolysosomes of NPC1 Mutant Cells." Cells 9, no. 5 (May 7, 2020): 1152. http://dx.doi.org/10.3390/cells9051152.
Full textAbstract:
We recently identified elevated annexin A6 (AnxA6) protein levels in Niemann–Pick-type C1 (NPC1) mutant cells. In these cells, AnxA6 depletion rescued the cholesterol accumulation associated with NPC1 deficiency. Here, we demonstrate that elevated AnxA6 protein levels in NPC1 mutants or upon pharmacological NPC1 inhibition, using U18666A, were not due to upregulated AnxA6 mRNA expression, but caused by defects in AnxA6 protein degradation. Two KFERQ-motifs are believed to target AnxA6 to lysosomes for chaperone-mediated autophagy (CMA), and we hypothesized that the cholesterol accumulation in endolysosomes (LE/Lys) triggered by the NPC1 inhibition could interfere with the CMA pathway. Therefore, AnxA6 protein amounts and cholesterol levels in the LE/Lys (LE-Chol) compartment were analyzed in NPC1 mutant cells ectopically expressing lysosome-associated membrane protein 2A (Lamp2A), which is well known to induce the CMA pathway. Strikingly, AnxA6 protein amounts were strongly decreased and coincided with significantly reduced LE-Chol levels in NPC1 mutant cells upon Lamp2A overexpression. Therefore, these findings suggest Lamp2A-mediated restoration of CMA in NPC1 mutant cells to lower LE-Chol levels with concomitant lysosomal AnxA6 degradation. Collectively, we propose CMA to permit a feedback loop between AnxA6 and cholesterol levels in LE/Lys, encompassing a novel mechanism for regulating cholesterol homeostasis in NPC1 disease.
10
Gläser, Anne, Franziska Hammerl, Markus H. Gräler, Sina M. Coldewey, Christin Völkner, Moritz J. Frech, Fan Yang, et al. "Identification of Brain-Specific Treatment Effects in NPC1 Disease by Focusing on Cellular and Molecular Changes of Sphingosine-1-Phosphate Metabolism." International Journal of Molecular Sciences 21, no. 12 (June 24, 2020): 4502. http://dx.doi.org/10.3390/ijms21124502.
Full textAbstract:
Niemann–Pick type C1 (NPC1) is a lysosomal storage disorder, inherited as an autosomal-recessive trait. Mutations in the Npc1 gene result in malfunction of the NPC1 protein, leading to an accumulation of unesterified cholesterol and glycosphingolipids. Beside visceral symptoms like hepatosplenomegaly, severe neurological symptoms such as ataxia occur. Here, we analyzed the sphingosine-1-phosphate (S1P)/S1P receptor (S1PR) axis in different brain regions of Npc1−/− mice and evaluated specific effects of treatment with 2-hydroxypropyl-β-cyclodextrin (HPβCD) together with the iminosugar miglustat. Using high-performance thin-layer chromatography (HPTLC), mass spectrometry, quantitative real-time PCR (qRT-PCR) and western blot analyses, we studied lipid metabolism in an NPC1 mouse model and human skin fibroblasts. Lipid analyses showed disrupted S1P metabolism in Npc1−/− mice in all brain regions, together with distinct changes in S1pr3/S1PR3 and S1pr5/S1PR5 expression. Brains of Npc1−/− mice showed only weak treatment effects. However, side effects of the treatment were observed in Npc1+/+ mice. The S1P/S1PR axis seems to be involved in NPC1 pathology, showing only weak treatment effects in mouse brain. S1pr expression appears to be affected in human fibroblasts, induced pluripotent stem cells (iPSCs)-derived neural progenitor and neuronal differentiated cells. Nevertheless, treatment-induced side effects make examination of further treatment strategies indispensable.
11
Witt, Martin, René Thiemer, Anja Meyer, Oliver Schmitt, and Andreas Wree. "Main Olfactory and Vomeronasal Epithelium Are Differently Affected in Niemann-Pick Disease Type C1." International Journal of Molecular Sciences 19, no. 11 (November 12, 2018): 3563. http://dx.doi.org/10.3390/ijms19113563.
Full textAbstract:
Introduction: Olfactory impairment is one of the earliest symptoms in neurodegenerative disorders that has also been documented in Niemann-Pick disease type C1 (NPC1). NPC1 is a very rare, neurovisceral lipid storage disorder, characterized by a deficiency of Npc1 gene function that leads to progressive neurodegeneration. Here, we compared the pathologic effect of defective Npc1 gene on the vomeronasal neuroepithelium (VNE) with that of the olfactory epithelium (OE) in an NPC1 mouse model. Methods: Proliferation in the VNE and OE was assessed by applying a bromodeoxyuridine (BrdU) protocol. We further compared the immunoreactivities of anti-olfactory marker protein (OMP), and the lysosomal marker cathepsin-D in both epithelia. To investigate if degenerative effects of both olfactory systems can be prevented or reversed, some animals were treated with a combination of miglustat/allopregnanolone/2-hydroxypropyl-cyclodextrin (HPβCD), or a monotherapy with HPβCD alone. Results: Using BrdU to label dividing cells of the VNE, we detected a proliferation increase of 215% ± 12% in Npc1−/− mice, and 270% ± 10% in combination- treated Npc1−/− animals. The monotherapy with HPβCD led to an increase of 261% ± 10.5% compared to sham-treated Npc1−/− mice. Similar to the OE, we assessed the high regenerative potential of vomeronasal progenitor cells. OMP reactivity in the VNE of Npc1−/− mice was not affected, in contrast to that observed in the OE. Concomitantly, cathepsin-D reactivity in the VNE was virtually absent. Conclusion: Vomeronasal receptor neurons are less susceptible against NPC1 pathology than olfactory receptor neurons. Compared to control mice, however, the VNE of Npc1−/− mice displays an increased neuroregenerative potential, indicating compensatory cell renewal.
12
Völkner, Christin, Maik Liedtke, Andreas Hermann, and Moritz J. Frech. "Pluripotent Stem Cells for Disease Modeling and Drug Discovery in Niemann-Pick Type C1." International Journal of Molecular Sciences 22, no. 2 (January 12, 2021): 710. http://dx.doi.org/10.3390/ijms22020710.
Full textAbstract:
The lysosomal storage disorders Niemann-Pick disease Type C1 (NPC1) and Type C2 (NPC2) are rare diseases caused by mutations in the NPC1 or NPC2 gene. Both NPC1 and NPC2 are proteins responsible for the exit of cholesterol from late endosomes and lysosomes (LE/LY). Consequently, mutations in one of the two proteins lead to the accumulation of unesterified cholesterol and glycosphingolipids in LE/LY, displaying a disease hallmark. A total of 95% of cases are due to a deficiency of NPC1 and only 5% are caused by NPC2 deficiency. Clinical manifestations include neurological symptoms and systemic symptoms, such as hepatosplenomegaly and pulmonary manifestations, the latter being particularly pronounced in NPC2 patients. NPC1 and NPC2 are rare diseases with the described neurovisceral clinical picture, but studies with human primary patient-derived neurons and hepatocytes are hardly feasible. Obviously, induced pluripotent stem cells (iPSCs) and their derivatives are an excellent alternative for indispensable studies with these affected cell types to study the multisystemic disease NPC1. Here, we present a review focusing on studies that have used iPSCs for disease modeling and drug discovery in NPC1 and draw a comparison to commonly used NPC1 models.
13
Pathmasiri, Koralege C., Melissa R. Pergande, Fernando Tobias, Rima Rebiai, Avia Rosenhouse-Dantsker, Ernesto R. Bongarzone, and Stephanie M. Cologna. "Mass spectrometry imaging and LC/MS reveal decreased cerebellar phosphoinositides in Niemann-Pick type C1-null mice." Journal of Lipid Research 61, no. 7 (May 5, 2020): 1004–13. http://dx.doi.org/10.1194/jlr.ra119000606.
Full textAbstract:
Niemann-Pick disease type C1 (NPC1) is a lipid storage disorder in which cholesterol and glycosphingolipids accumulate in late endosomal/lysosomal compartments because of mutations in the NPC1 gene. A hallmark of NPC1 is progressive neurodegeneration of the cerebellum as well as visceral organ damage; however, the mechanisms driving this disease pathology are not fully understood. Phosphoinositides are phospholipids that play distinct roles in signal transduction and vesicle trafficking. Here, we utilized a consensus spectra analysis of MS imaging data sets and orthogonal LC/MS analyses to evaluate the spatial distribution of phosphoinositides and quantify them in cerebellar tissue from Npc1-null mice. Our results suggest significant depletion of multiple phosphoinositide species, including PI, PIP, and PIP2, in the cerebellum of the Npc1-null mice in both whole-tissue lysates and myelin-enriched fractions. Additionally, we observed altered levels of the regulatory enzyme phosphatidylinositol 4-kinase type 2α in Npc1-null mice. In contrast, the levels of related kinases, phosphatases, and transfer proteins were unaltered in the Npc1-null mouse model, as observed by Western blot analysis. Our discovery of phosphoinositide lipid biomarkers for NPC1 opens new perspectives on the pathophysiology underlying this fatal neurodegenerative disease.
14
O’Neill, Kathleen I., Li-Wei Kuo, Michelle M. Williams, Hanne Lind, Lyndsey S. Crump, Nia G. Hammond, Nicole S. Spoelstra, Cecilia M. Caino, and Jennifer K. Richer. "NPC1 Confers Metabolic Flexibility in Triple Negative Breast Cancer." Cancers 14, no. 14 (July 21, 2022): 3543. http://dx.doi.org/10.3390/cancers14143543.
Full textAbstract:
Triple-negative breast cancer (TNBC) often undergoes at least partial epithelial-to-mesenchymal transition (EMT) to facilitate metastasis. Identifying EMT-associated characteristics can reveal novel dependencies that may serve as therapeutic vulnerabilities in this aggressive breast cancer subtype. We found that NPC1, which encodes the lysosomal cholesterol transporter Niemann–Pick type C1 is highly expressed in TNBC as compared to estrogen receptor-positive (ER+) breast cancer, and is significantly elevated in high-grade disease. We demonstrated that NPC1 is directly targeted by microRNA-200c (miR-200c), a potent suppressor of EMT, providing a mechanism for its differential expression in breast cancer subtypes. The silencing of NPC1 in TNBC causes an accumulation of cholesterol-filled lysosomes, and drives decreased growth in soft agar and invasive capacity. Conversely, overexpression of NPC1 in an ER+ cell line increases invasion and growth in soft agar. We further identified TNBC cell lines as cholesterol auxotrophs, however, they do not solely depend on NPC1 for adequate cholesterol supply. The silencing of NPC1 in TNBC cell lines led to altered mitochondrial function and morphology, suppression of mTOR signaling, and accumulation of autophagosomes. A small molecule inhibitor of NPC1, U18666A, decreased TNBC proliferation and synergized with the chemotherapeutic drug, paclitaxel. This work suggests that NPC1 promotes aggressive characteristics in TNBC, and identifies NPC1 as a potential therapeutic target.
15
Jürs, Alexandra V., Christin Völkner, Maik Liedtke, Katharina Huth, Jan Lukas, Andreas Hermann, and Moritz J. Frech. "Oxidative Stress and Alterations in the Antioxidative Defense System in Neuronal Cells Derived from NPC1 Patient-Specific Induced Pluripotent Stem Cells." International Journal of Molecular Sciences 21, no. 20 (October 16, 2020): 7667. http://dx.doi.org/10.3390/ijms21207667.
Full textAbstract:
Oxidative stress (OS) represents a state of an imbalanced amount of reactive oxygen species (ROS) and/or a hampered efficacy of the antioxidative defense system. Cells of the central nervous system are particularly sensitive to OS, as they have a massive need of oxygen to maintain proper function. Consequently, OS represents a common pathophysiological hallmark of neurodegenerative diseases and is discussed to contribute to the neurodegeneration observed amongst others in Alzheimer’s disease and Parkinson’s disease. In this context, accumulating evidence suggests that OS is involved in the pathophysiology of Niemann-Pick type C1 disease (NPC1). NPC1, a rare hereditary neurodegenerative disease, belongs to the family of lysosomal storage disorders. A major hallmark of the disease is the accumulation of cholesterol and other glycosphingolipids in lysosomes. Several studies describe OS both in murine in vivo and in vitro NPC1 models. However, studies based on human cells are limited to NPC1 patient-derived fibroblasts. Thus, we analyzed OS in a human neuronal model based on NPC1 patient-specific induced pluripotent stem cells (iPSCs). Higher ROS levels, as determined by DCF (dichlorodihydrofluorescein) fluorescence, indicated oxidative stress in all NPC1-deficient cell lines. This finding was further supported by reduced superoxide dismutase (SOD) activity. The analysis of mRNA and protein levels of SOD1 and SOD2 did not reveal any difference between control cells and NPC1-deficient cells. Interestingly, we observed a striking decrease in catalase mRNA and protein levels in all NPC1-deficient cell lines. As catalase is a key enzyme of the cellular antioxidative defense system, we concluded that the lack of catalase contributes to the elevated ROS levels observed in NPC1-deficient cells. Thus, a restitution of a physiological catalase level may pose an intervention strategy to rescue NPC1-deficient cells from the repercussions of oxidative stress contributing to the neurodegeneration observed in NPC1.
16
Rabenstein, Michael, Nico Murr, Andreas Hermann, Arndt Rolfs, and Moritz J. Frech. "Alteration of GABAergic Input Precedes Neurodegeneration of Cerebellar Purkinje Cells of NPC1-Deficient Mice." International Journal of Molecular Sciences 20, no. 24 (December 13, 2019): 6288. http://dx.doi.org/10.3390/ijms20246288.
Full textAbstract:
Niemann-Pick Disease Type C1 (NPC1) is a rare hereditary neurodegenerative disease belonging to the family of lysosomal storage disorders. NPC1-patients suffer from, amongst other symptoms, ataxia, based on the dysfunction and loss of cerebellar Purkinje cells. Alterations in synaptic transmission are believed to contribute to a pathological mechanism leading to the progressive loss of Purkinje cells observed in NPC1-deficient mice. With regard to inhibitory synaptic transmission, alterations of GABAergic synapses are described but functional data are missing. For this reason, we have examined here the inhibitory GABAergic synaptic transmission of Purkinje cells of NPC1-deficient mice (NPC1−/−). Patch clamp recordings of inhibitory post-synaptic currents (IPSCs) of Purkinje cells revealed an increased frequency of GABAergic IPSCs in NPC1−/− mice. In addition, Purkinje cells of NPC1−/− mice were less amenable for modulation of synaptic transmission via the activation of excitatory NMDA-receptors (NMDA-Rs). Western blot testing disclosed a reduced protein level of phosphorylated alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPA-Rs) subunit GluA2 in the cerebella of NPC1−/− mice, indicating a disturbance in the internalization of GluA2-containing AMPA-Rs. Since this is triggered by the activation of NMDA-Rs, we conclude that a disturbance in the synaptic turnover of AMPA-Rs underlies the defective inhibitory GABAergic synaptic transmission. While these alterations precede obvious signs of neurodegeneration of Purkinje cells, we propose a contribution of synaptic malfunction to the initiation of the loss of Purkinje cells in NPC1. Thus, a prevention of the disturbance of synaptic transmission in early stages of the disease might display a target with which to avert progressive neurodegeneration in NPC1.
17
Lin, Yusheng, Xiaolian Cai, Guiping Wang, Gang Ouyang, and Hong Cao. "Model construction of Niemann-Pick type C disease in zebrafish." Biological Chemistry 399, no. 8 (July 26, 2018): 903–10. http://dx.doi.org/10.1515/hsz-2018-0118.
Full textAbstract:
Abstract Niemann-Pick type C disease (NPC) is a rare human disease, with limited effective treatment options. Most cases of NPC disease are associated with inactivating mutations of the NPC1 gene. However, cellular and molecular mechanisms responsible for the NPC1 pathogenesis remain poorly defined. This is partly due to the lack of a suitable animal model to monitor the disease progression. In this study, we used CRISPR to construct an NPC1−/− zebrafish model, which faithfully reproduced the cardinal pathological features of this disease. In contrast to the wild type (WT), the deletion of NPC1 alone caused significant hepatosplenomegaly, ataxia, Purkinje cell death, increased lipid storage, infertility and reduced body length and life span. Most of the NPC1−/− zebrafish died within the first month post fertilization, while the remaining specimens developed slower than the WT and died before reaching 8 months of age. Filipin-stained hepatocytes of the NPC1−/− zebrafish were clear, indicating abnormal accumulation of unesterified cholesterol. Lipid profiling showed a significant difference between NPC1−/− and WT zebrafish. An obvious accumulation of seven sphingolipids was detected in livers of NPC1−/− zebrafish. In summary, our results provide a valuable model system that could identify promising therapeutic targets and treatments for the NPC disease.
18
Rodriguez-Gil, Jorge L., Dawn E. Watkins-Chow, Laura L. Baxter, Tadafumi Yokoyama, Patricia M. Zerfas, Matthew F. Starost, William A. Gahl, et al. "NPC1 Deficiency in Mice is Associated with Fetal Growth Restriction, Neonatal Lethality and Abnormal Lung Pathology." Journal of Clinical Medicine 9, no. 1 (December 19, 2019): 12. http://dx.doi.org/10.3390/jcm9010012.
Full textAbstract:
The rare lysosomal storage disorder Niemann-Pick disease type C1 (NPC1) arises from mutation of NPC1, which encodes a lysosomal transmembrane protein essential for normal transport and trafficking of cholesterol and sphingolipids. NPC1 is highly heterogeneous in both clinical phenotypes and age of onset. Previous studies have reported sub-Mendelian survival rates for mice homozygous for various Npc1 mutant alleles but have not studied the potential mechanisms underlying this phenotype. We performed the first developmental analysis of a Npc1 mouse model, Npc1em1Pav, and discovered significant fetal growth restriction in homozygous mutants beginning at E16.5. Npc1em1Pav/em1Pav mice also exhibited cyanosis, increased respiratory effort, and over 50% lethality at birth. Analysis of neonatal lung tissues revealed lipid accumulation, notable abnormalities in surfactant, and enlarged alveolar macrophages, suggesting that lung abnormalities may be associated with neonatal lethality in Npc1em1Pav/em1Pav mice. The phenotypic severity of the Npc1em1Pav model facilitated this first analysis of perinatal lethality and lung pathology in an NPC1 model organism, and this model may serve as a useful resource for developing treatments for respiratory complications seen in NPC1 patients.
19
Infante, Rodney E., Michael L. Wang, Arun Radhakrishnan, Hyock Joo Kwon, Michael S. Brown, and Joseph L. Goldstein. "NPC2 facilitates bidirectional transfer of cholesterol between NPC1 and lipid bilayers, a step in cholesterol egress from lysosomes." Proceedings of the National Academy of Sciences 105, no. 40 (September 4, 2008): 15287–92. http://dx.doi.org/10.1073/pnas.0807328105.
Full textAbstract:
Egress of lipoprotein-derived cholesterol from lysosomes requires two lysosomal proteins, polytopic membrane-bound Niemann–Pick C1 (NPC1) and soluble Niemann–Pick C2 (NPC2). The reason for this dual requirement is unknown. Previously, we showed that the soluble luminal N-terminal domain (NTD) of NPC1 (amino acids 25–264) binds cholesterol. This NTD is designated NPC1(NTD). We and others showed that soluble NPC2 also binds cholesterol. Here, we establish an in vitro assay to measure transfer of [3H]cholesterol between these two proteins and phosphatidylcholine liposomes. Whereas NPC2 rapidly donates or accepts cholesterol from liposomes, NPC1(NTD) acts much more slowly. Bidirectional transfer of cholesterol between NPC1(NTD) and liposomes is accelerated >100-fold by NPC2. A naturally occurring human mutant of NPC2 (Pro120Ser) fails to bind cholesterol and fails to stimulate cholesterol transfer from NPC1(NTD) to liposomes. NPC2 may be essential to deliver or remove cholesterol from NPC1, an interaction that links both proteins to the cholesterol egress process from lysosomes. These findings may explain how mutations in either protein can produce a similar clinical phenotype.
20
Holzmann, Carsten, Martin Witt, Arndt Rolfs, Veronica Antipova, and Andreas Wree. "Gender-Specific Effects of Two Treatment Strategies in a Mouse Model of Niemann-Pick Disease Type C1." International Journal of Molecular Sciences 22, no. 5 (March 3, 2021): 2539. http://dx.doi.org/10.3390/ijms22052539.
Full textAbstract:
In a mouse model of Niemann-Pick disease type C1 (NPC1), a combination therapy (COMBI) of miglustat (MIGLU), the neurosteroid allopregnanolone (ALLO) and the cyclic oligosaccharide 2-hydroxypropyl-β-cyclodextrin (HPßCD) has previously resulted in, among other things, significantly improved motor function. The present study was designed to compare the therapeutic effects of the COMBI therapy with that of MIGLU or HPßCD alone on body and brain weight and the behavior of NPC1−/− mice in a larger cohort, with special reference to gender differences. A total of 117 NPC1−/− and 123 NPC1+/+ mice underwent either COMBI, MIGLU only, HPßCD only, or vehicle treatment (Sham), or received no treatment at all (None). In male and female NPC1−/− mice, all treatments led to decreased loss of body weight and, partly, brain weight. Concerning motor coordination, as revealed by the accelerod test, male NPC1−/− mice benefited from COMBI treatment, whereas female mice benefited from COMBI, MIGLU, and HPßCD treatment. As seen in the open field test, the reduced locomotor activity of male and female NPC1−/− mice was not significantly ameliorated in either treatment group. Our results suggest that in NPC1−/− mice, each drug treatment scheme had a beneficial effect on at least some of the parameters evaluated compared with Sham-treated mice. Only in COMBI-treated male and female NPC+/+ mice were drug effects seen in reduced body and brain weights. Upon COMBI treatment, the increased dosage of drugs necessary for anesthesia in Sham-treated male and female NPC1−/− mice was almost completely reduced only in the female groups.
21
Ortega-Gonzalez, Paula, Gwen Taylor, Rohit K. Jangra, Raquel Tenorio, Isabel Fernandez de Castro, Bernardo A. Mainou, Robert C. Orchard, et al. "Reovirus infection is regulated by NPC1 and endosomal cholesterol homeostasis." PLOS Pathogens 18, no. 3 (March 9, 2022): e1010322. http://dx.doi.org/10.1371/journal.ppat.1010322.
Full textAbstract:
Cholesterol homeostasis is required for the replication of many viruses, including Ebola virus, hepatitis C virus, and human immunodeficiency virus-1. Niemann-Pick C1 (NPC1) is an endosomal-lysosomal membrane protein involved in cholesterol trafficking from late endosomes and lysosomes to the endoplasmic reticulum. We identified NPC1 in CRISPR and RNA interference screens as a putative host factor for infection by mammalian orthoreovirus (reovirus). Following internalization via clathrin-mediated endocytosis, the reovirus outer capsid is proteolytically removed, the endosomal membrane is disrupted, and the viral core is released into the cytoplasm where viral transcription, genome replication, and assembly take place. We found that reovirus infection is significantly impaired in cells lacking NPC1, but infection is restored by treatment of cells with hydroxypropyl-β-cyclodextrin, which binds and solubilizes cholesterol. Absence of NPC1 did not dampen infection by infectious subvirion particles, which are reovirus disassembly intermediates that bypass the endocytic pathway for infection of target cells. NPC1 is not required for reovirus attachment to the plasma membrane, internalization into cells, or uncoating within endosomes. Instead, NPC1 is required for delivery of transcriptionally active reovirus core particles from endosomes into the cytoplasm. These findings suggest that cholesterol homeostasis, ensured by NPC1 transport activity, is required for reovirus penetration into the cytoplasm, pointing to a new function for NPC1 and cholesterol homeostasis in viral infection.
22
Harskamp, Jessica C., Joya E. Nahon, Andrea M. Siegel, Hans L. Vos, Piëette P. Deutz-Terlouw, J. Hendrik Veelken, J. H. Frederik Falkenburg, and Erik W. A. Marijt. "Quantitative Monitoring of NPM1A Mutations Can Be Used to Guide Immunotherapeutic Interventions After Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia." Blood 118, no. 21 (November 18, 2011): 3061. http://dx.doi.org/10.1182/blood.v118.21.3061.3061.
Full textAbstract:
Abstract Abstract 3061 Allogeneic stem cell transplantation (alloSCT) is a potentially curative treatment for patients (pts) with acute myeloid leukemia (AML). However, approximately 30% of the transplanted AML pts develop a clinical relapse. Relapsing AML often clinically presents with a rapid increase in leukemic cell load, making current treatment options less effective. In order to prevent an overt clinical relapse, early detection of an impending relapse to guide pre-emptive immunotherapeutic interventions is important. After alloSCT mixed chimerism (MC) reflects the persistence of pt hematopoietic cells including the malignant hematopoietic cell population. It has been shown that donor lymphocytes can be administered to AML pts with MC at 6 months post alloSCT with a relative low risk of graft versus host disease (GvHD). However, a high percentage of pts still suffers from relapse in the first 6 months. An option to decrease the incidence of this early relapse is the pre-emptive administration of donor lymphocytes prior to 6 months after alloSCT. However, this is associated with a higher risk of potentially life threatening GvHD. Since chimerism analysis will also reflect the persistence of non-malignant pt cells, donor lymphocyte infusion (DLI) based on MC could cause overtreatment. Therefore, availability of tumor specific and sensitive methods to monitor minimal residual disease (MRD) is necessary. Recently, a quantitative real-time polymerase chain reaction (RQ-PCR) assay to detect NPM1 type A mutations in NPM1 positive AML pts has proven suitable for MRD detection and strong correlations were found between clinical courses and the residual mutation load post-transplant. In the current study, we prospectively analyzed in a cohort of 13 NPM1A positive AML pts whether the NPM1A mutation level and or chimerism analysis in bone marrow (BM) at three months after alloSCT can be used as a guide to select pts for pre-emptive immunotherapeutic intervention. Chimerism analysis was performed using short tandem repeats PCR with a sensitivity of 1–5%. NPM1A levels were quantified by RQ-PCR with a detection limit of 6×10–4. Clinical relapse was defined as >5% blasts in BM. 3/13 Pts died in remission from infectious complications less than 3 months after alloSCT. These pts were MC and NPM1A negative. 2/13 Pts received pre-emptive DLI at 3 months based on high-risk disease alone. In the remaining 8/13 pts, without immunotherapeutic intervention in the first six months after alloSCT, chimerism and NPM1A levels at 3 months after alloSCT were compared with regard to prediction of early clinical relapse. 3/8 Pts were complete donor chimeric without detectable NPM1A and have remained in continuous complete remission. 2/8 Pts with MC and detectable NPM1A at 3 months had frank clinical relapse 14 days and 41 days later, respectively. However, 3/8 pts were MC while the NPM1A mutation was absent, and these pts did not develop a relapse within the first 6 months post alloSCT. To investigate if pre-emptive immunotherapeutic intervention could be guided by NPM1A MRD levels, we analyzed NPM1A levels in 4/13 pts who received pre-planned DLI in complete remission for MC according to institutional guidelines. 3/4 Pts were consistently NPM1A-negative. One of these pts had received two low dose DLIs at 4 and 9 months after alloSCT based on high risk disease and MC, respectively. Despite these interventions, increasing NPM1A levels were detected in five consecutive samples between 12–18 months after alloSCT. Therefore, a third high dose DLI was given at 17 months after alloSCT. Two months after this DLI, the NPM1A mutation became undetectable for the entire follow-up period of three years, and the pt remained alive in complete remission. In conclusion, these data illustrate that quantitative monitoring of NPM1A is a more sensitive marker to predict relapse early after alloSCT as compared to chimerism analysis. Furthermore, we conclude that pre-emptive immunotherapeutic intervention based on highly sensitive detection of molecular relapse can be effective in eliminating the malignant AML cells and thereby prevent clinical relapses. Disclosures: No relevant conflicts of interest to declare.
23
Igarashi, Manabu, Takatsugu Hirokawa, Yoshihiro Takadate, and Ayato Takada. "Structural Insights into the Interaction of Filovirus Glycoproteins with the Endosomal Receptor Niemann-Pick C1: A Computational Study." Viruses 13, no. 5 (May 14, 2021): 913. http://dx.doi.org/10.3390/v13050913.
Full textAbstract:
Filoviruses, including marburgviruses and ebolaviruses, have a single transmembrane glycoprotein (GP) that facilitates their entry into cells. During entry, GP needs to be cleaved by host proteases to expose the receptor-binding site that binds to the endosomal receptor Niemann-Pick C1 (NPC1) protein. The crystal structure analysis of the cleaved GP (GPcl) of Ebola virus (EBOV) in complex with human NPC1 has demonstrated that NPC1 has two protruding loops (loops 1 and 2), which engage a hydrophobic pocket on the head of EBOV GPcl. However, the molecular interactions between NPC1 and the GPcl of other filoviruses remain unexplored. In the present study, we performed molecular modeling and molecular dynamics simulations of NPC1 complexed with GPcls of two ebolaviruses, EBOV and Sudan virus (SUDV), and one marburgvirus, Ravn virus (RAVV). Similar binding structures were observed in the GPcl–NPC1 complexes of EBOV and SUDV, which differed from that of RAVV. Specifically, in the RAVV GPcl–NPC1 complex, the tip of loop 2 was closer to the pocket edge comprising residues at positions 79–88 of GPcl; the root of loop 1 was predicted to interact with P116 and Q144 of GPcl. Furthermore, in the SUDV GPcl–NPC1 complex, the tip of loop 2 was slightly closer to the residue at position 141 than those in the EBOV and RAVV GPcl–NPC1 complexes. These structural differences may affect the size and/or shape of the receptor-binding pocket of GPcl. Our structural models could provide useful information for improving our understanding the differences in host preference among filoviruses as well as contributing to structure-based drug design.
24
Williams, Isabelle, Sumeet Pandey, Wolfram Haller, Hien Quoc Huynh, Alicia Chan, Gesche Düeker, Ruth Bettels, et al. "Anti-TNF therapy for inflammatory bowel disease in patients with neurodegenerative Niemann-Pick disease Type C." Wellcome Open Research 7 (January 11, 2022): 11. http://dx.doi.org/10.12688/wellcomeopenres.16986.1.
Full textAbstract:
Background: Blockade of tumour necrosis factor (anti-TNF) is effective in patients with Crohn’s Disease but has been associated with infection risk and neurological complications such as demyelination. Niemann-Pick disease Type C1 (NPC1) is a lysosomal storage disorder presenting in childhood with neurological deterioration, liver damage and respiratory infections. Some NPC1 patients develop severe Crohn’s disease. Our objective was to investigate the safety and effectiveness of anti-TNF in NPC1 patients with Crohn’s disease. Methods: Retrospective data on phenotype and therapy response were collected in 2019-2020 for the time period 2014 to 2020 from patients in the UK, France, Germany and Canada with genetically confirmed NPC1 defects and intestinal inflammation. We investigated TNF secretion in peripheral blood mononuclear cells treated with NPC1 inhibitor in response to bacterial stimuli. Results: NPC1 inhibitor treated peripheral blood mononuclear cells (PBMCs) show significantly increased TNF production after lipopolysaccharide or bacterial challenge providing a rationale for anti-TNF therapy. We identified 4 NPC1 patients with Crohn’s disease (CD)-like intestinal inflammation treated using anti-TNF therapy (mean age of onset 8.1 years, mean treatment length 27.75 months, overall treatment period 9.25 patient years). Anti-TNF therapy was associated with reduced gastrointestinal symptoms with no apparent adverse neurological events. Therapy improved intestinal inflammation in 4 patients. Conclusions: Anti-TNF therapy appears safe in patients with NPC1 and is an effective treatment strategy for the management of intestinal inflammation in these patients.
25
Seker Yilmaz, Berna, Julien Baruteau, Ahad A. Rahim, and Paul Gissen. "Clinical and Molecular Features of Early Infantile Niemann Pick Type C Disease." International Journal of Molecular Sciences 21, no. 14 (July 17, 2020): 5059. http://dx.doi.org/10.3390/ijms21145059.
Full textAbstract:
Niemann Pick disease type C (NPC) is a neurovisceral disorder due to mutations in NPC1 or NPC2. This review focuses on poorly characterized clinical and molecular features of early infantile form of NPC (EIF) and identified 89 cases caused by NPC1 (NPC1) and 16 by NPC2 (NPC2) mutations. Extra-neuronal features were common; visceromegaly reported in 80/89 NPC1 and in 15/16 NPC2, prolonged jaundice in 30/89 NPC1 and 7/16 NPC2. Early lung involvement was present in 12/16 NPC2 cases. Median age of neurological onset was 12 (0–24) and 7.5 (0–24) months in NPC1 and NPC2 groups, respectively. Developmental delay and hypotonia were the commonest first detected neurological symptoms reported in 39/89 and 18/89 NPC1, and in 8/16 and 10/16 NPC2, respectively. Additional neurological symptoms included vertical supranuclear gaze palsy, dysarthria, cataplexy, dysphagia, seizures, dystonia, and spasticity. The following mutations in homozygous state conferred EIF: deletion of exon 1+promoter, c.3578_3591 + 9del, c.385delT, p.C63fsX75, IVS21-2delATGC, c. 2740T>A (p.C914S), c.3584G>T (p.G1195V), c.3478-6T>A, c.960_961dup (p.A321Gfs*16) in NPC1 and c.434T>A (p.V145E), c.199T>C (p.S67P), c.133C>T (p.Q45X), c.141C>A (p.C47X) in NPC2. This comprehensive analysis of the EIF type of NPC will benefit clinical patient management, genetic counselling, and assist design of novel therapy trials.
26
Pergande, Melissa, Antony Cougnoux, Rathnayake Rathnayake, Forbes Porter, and Stephanie Cologna. "Differential Proteomics Reveals miR-155 as a Novel Indicator of Liver and Spleen Pathology in the Symptomatic Niemann-Pick Disease, Type C1 Mouse Model." Molecules 24, no. 5 (March 12, 2019): 994. http://dx.doi.org/10.3390/molecules24050994.
Full textAbstract:
Niemann-Pick disease, type C1 (NPC1) is a rare, autosomal recessive, lipid storage disorder caused by mutations in NPC1. As a result, there is accumulation of unesterified cholesterol and sphingolipids in the late endosomal/lysosomal system. Clinically, patients can present with splenomegaly and hepatomegaly. In the current study, we analyzed the differential proteome of the spleen in symptomatic Npc1−/− mice to complement previous studies focused on the differential proteome of the liver, and then evaluated biomolecules that may serve as tissue biomarkers. The proteomic analysis revealed altered pathways in NPC1 representing different functional categories including heme synthesis, cellular regulation and phosphoinositide metabolism in both tissues. Differential proteins included several activators of the ubiquitous and critical protein, Akt, a major kinase involved in multiple cellular processes. Evaluation of Akt revealed decreased expression in both the liver and spleen tissues of symptomatic Npc1−/− mice. Upstream regulation analysis also suggested that miR-155 may modulate the differences of known downstream protein targets observed in our dataset. Upon evaluation of miR-155, we observed an increased expression in the liver and decreased expression in the spleen of symptomatic Npc1−/− mice. Here, we propose that miR-155 may be a novel indicator of spleen and liver pathology in NPC1.
27
Roth, Sebastian, Henrik Fox, René M’Pembele, Michiel Morshuis, Giovanna Lurati Buse, Markus W. Hollmann, Ragnar Huhn, and Thomas Bitter. "Noninvasive evaluation of the hemodynamic status in patients after heart transplantation or left ventricular assist device implantation." PLOS ONE 17, no. 10 (October 14, 2022): e0275977. http://dx.doi.org/10.1371/journal.pone.0275977.
Full textAbstract:
Introduction Hemodynamic assessment is crucial after heart transplantation (HTX) or left ventricular assist device (LVAD) implantation. Gold-standard is invasive assessment via thermodilution (TD). Noninvasive pulse contour analysis (NPCA) is a new technology that is supposed to determine hemodynamics completely noninvasive. We aimed to validate this technology in HTX and LVAD patients and conducted a prospective single-center cohort study. Methods Patients after HTX or LVAD implantation underwent right heart catheterization including TD. NPCA using the CNAP Monitor (V.5.2.14; CNSystems Medizintechnik AG, Graz, Austria) was performed simultaneously. Three TD measurements were compared with simultaneous NPCA measurements for hemodynamic assessment. To describe the agreement between TD and NPCA, Bland–Altman analysis was done. Results In total, 28 patients were prospectively enrolled (HTX: n = 10, LVAD: n = 18). Bland-Altman analysis revealed a mean bias of +1.05 l/min (limits of agreement ± 4.09 l/min, percentage error 62.1%) for cardiac output (CO). In LVAD patients, no adequate NPCA signal could be obtained. In 5 patients (27.8%), any NPCA signal could be detected, but was considered as low signal quality. Conclusion In conclusion, according to our limited data in a small cohort of HTX and LVAD patients, NPCA using the CNAP Monitor seems not to be suitable for noninvasive evaluation of the hemodynamic status.
28
Dominko, Kristina, Ana Rastija, Sandra Sobocanec, Lea Vidatic, Sarah Meglaj, Andrea Lovincic Babic, Birgit Hutter-Paier, et al. "Impaired Retromer Function in Niemann-Pick Type C Disease Is Dependent on Intracellular Cholesterol Accumulation." International Journal of Molecular Sciences 22, no. 24 (December 9, 2021): 13256. http://dx.doi.org/10.3390/ijms222413256.
Full textAbstract:
Niemann-Pick type C disease (NPC) is a rare inherited neurodegenerative disorder characterized by an accumulation of intracellular cholesterol within late endosomes and lysosomes due to NPC1 or NPC2 dysfunction. In this work, we tested the hypothesis that retromer impairment may be involved in the pathogenesis of NPC and may contribute to increased amyloidogenic processing of APP and enhanced BACE1-mediated proteolysis observed in NPC disease. Using NPC1-null cells, primary mouse NPC1-deficient neurons and NPC1-deficient mice (BALB/cNctr-Npc1m1N), we show that retromer function is impaired in NPC. This is manifested by altered transport of the retromer core components Vps26, Vps35 and/or retromer receptor sorLA and by retromer accumulation in neuronal processes, such as within axonal swellings. Changes in retromer distribution in NPC1 mouse brains were observed already at the presymptomatic stage (at 4-weeks of age), indicating that the retromer defect occurs early in the course of NPC disease and may contribute to downstream pathological processes. Furthermore, we show that cholesterol depletion in NPC1-null cells and in NPC1 mouse brains reverts retromer dysfunction, suggesting that retromer impairment in NPC is mechanistically dependent on cholesterol accumulation. Thus, we characterized retromer dysfunction in NPC and propose that the rescue of retromer impairment may represent a novel therapeutic approach against NPC.
29
Takadate, Yoshihiro, Rashid Manzoor, Takeshi Saito, Yurie Kida, Junki Maruyama, Tatsunari Kondoh, Hiroko Miyamoto, et al. "Receptor-Mediated Host Cell Preference of a Bat-Derived Filovirus, Lloviu Virus." Microorganisms 8, no. 10 (October 5, 2020): 1530. http://dx.doi.org/10.3390/microorganisms8101530.
Full textAbstract:
Lloviu virus (LLOV), a bat-derived filovirus that is phylogenetically distinct from human pathogenic filoviruses such as Ebola virus (EBOV) and Marburg virus (MARV), was discovered in Europe. However, since infectious LLOV has never been isolated, the biological properties of this virus remain poorly understood. We found that vesicular stomatitis virus (VSV) pseudotyped with the glycoprotein (GP) of LLOV (VSV–LLOV) showed higher infectivity in one bat (Miniopterus sp.)-derived cell line than in the other bat-derived cell lines tested, which was distinct from the tropism of VSV pseudotyped with EBOV (VSV–EBOV) and MARV GPs. We then focused on the interaction between GP and Niemann–Pick C1 (NPC1) protein, one of the cellular receptors of filoviruses. We introduced the Miniopterus bat and human NPC1 genes into NPC1-knockout Vero E6 cells and their susceptibilities to the viruses were compared. The cell line expressing the bat NPC1 showed higher susceptibility to VSV–LLOV than that expressing human NPC1, whereas the opposite preference was seen for VSV–EBOV. Using a site-directed mutagenesis approach, amino acid residues involved in the differential tropism were identified in the NPC1 and GP molecules. Our results suggest that the interaction between GP and NPC1 is an important factor in the tropism of LLOV to a particular bat species.
30
Chen, Oscar C. W., Stephan Siebel, Alexandria Colaco, Elena-Raluca Nicoli, Nick Platt, Dawn Shepherd, Stephanie Newman, et al. "Defective iron homeostasis and hematological abnormalities in Niemann-Pick disease type C1." Wellcome Open Research 7 (October 20, 2022): 267. http://dx.doi.org/10.12688/wellcomeopenres.17261.1.
Full textAbstract:
Background: Niemann-Pick disease type C1 (NPC1) is a neurodegenerative lysosomal storage disorder characterized by the accumulation of multiple lipids in the late endosome/lysosomal system and reduced acidic store calcium. The lysosomal system regulates key aspects of iron homeostasis, which prompted us to investigate whether there are hematological abnormalities and iron metabolism defects in NPC1. Methods: Iron-related hematological parameters, systemic and tissue metal ion and relevant hormonal and proteins levels, expression of specific pro-inflammatory mediators and erythrophagocytosis were evaluated in an authentic mouse model and in a large cohort of NPC patients. Results: Significant changes in mean corpuscular volume and corpuscular hemoglobin were detected in Npc1-/- mice from an early age. Hematocrit, red cell distribution width and hemoglobin changes were observed in late-stage disease animals. Systemic iron deficiency, increased circulating hepcidin, decreased ferritin and abnormal pro-inflammatory cytokine levels were also found. Furthermore, there is evidence of defective erythrophagocytosis in Npc1-/- mice and in an in vitro NPC1 cellular model. Comparable hematological changes, including low normal serum iron and transferrin saturation and low cerebrospinal fluid ferritin were confirmed in NPC1 patients. Conclusions: These data suggest loss of iron homeostasis and hematological abnormalities in NPC1 may contribute to the pathophysiology of this disease.
31
Infante, Rodney E., Lina Abi-Mosleh, Arun Radhakrishnan, Jarrod D. Dale, Michael S. Brown, and Joseph L. Goldstein. "Purified NPC1 Protein." Journal of Biological Chemistry 283, no. 2 (November 6, 2007): 1052–63. http://dx.doi.org/10.1074/jbc.m707943200.
Full text
32
Infante, Rodney E., Arun Radhakrishnan, Lina Abi-Mosleh, Lisa N. Kinch, Michael L. Wang, Nick V. Grishin, Joseph L. Goldstein, and Michael S. Brown. "Purified NPC1 Protein." Journal of Biological Chemistry 283, no. 2 (November 6, 2007): 1064–75. http://dx.doi.org/10.1074/jbc.m707944200.
Full text
33
Abelev, M. M., V. V. Dolganev, E. �. Kossovskaya, and M. A. Yastrebova. "Properties and use of NP1A-ID and NP1A nickel tubes." Chemical and Petroleum Engineering 28, no. 4 (April 1992): 268–70. http://dx.doi.org/10.1007/bf01148624.
Full text
34
Colaco, Alexandria, María E. Fernández-Suárez, Dawn Shepherd, Lihi Gal, Chen Bibi, Silvia Chuartzman, Alan Diot, et al. "Unbiased yeast screens identify cellular pathways affected in Niemann–Pick disease type C." Life Science Alliance 3, no. 7 (June 2, 2020): e201800253. http://dx.doi.org/10.26508/lsa.201800253.
Full textAbstract:
Niemann–Pick disease type C (NPC) is a rare lysosomal storage disease caused by mutations in either the NPC1 or NPC2 genes. Mutations in the NPC1 gene lead to the majority of clinical cases (95%); however, the function of NPC1 remains unknown. To gain further insights into the biology of NPC1, we took advantage of the homology between the human NPC1 protein and its yeast orthologue, Niemann–Pick C–related protein 1 (Ncr1). We recreated the NCR1 mutant in yeast and performed screens to identify compensatory or redundant pathways that may be involved in NPC pathology, as well as proteins that were mislocalized in NCR1-deficient yeast. We also identified binding partners of the yeast Ncr1 orthologue. These screens identified several processes and pathways that may contribute to NPC pathogenesis. These included alterations in mitochondrial function, cytoskeleton organization, metal ion homeostasis, lipid trafficking, calcium signalling, and nutrient sensing. The mitochondrial and cytoskeletal abnormalities were validated in patient cells carrying mutations in NPC1, confirming their dysfunction in NPC disease.
35
KARTEN, Barbara, Hideki HAYASHI, Gordon A. FRANCIS, Robert B. CAMPENOT, Dennis E. VANCE, and Jean E. VANCE. "Generation and function of astroglial lipoproteins from Niemann–Pick type C1-deficient mice." Biochemical Journal 387, no. 3 (April 26, 2005): 779–88. http://dx.doi.org/10.1042/bj20041694.
Full textAbstract:
NPC (Niemann–Pick type C) disease is a progressive neurological disorder characterized by defects in intracellular cholesterol trafficking, accumulation of cholesterol in the endosomal system and impaired cholesterol homoeostasis. Although these alterations appear to occur in all NPC1-deficient cell types, the consequences are most profound in the nervous system. Since glial cells are important mediators of brain cholesterol homoeostasis, we proposed that defective generation and/or function of lipoproteins released by glia might contribute to the neurological abnormalities associated with NPC disease. We found that, as in other cell types, Npc1−/− glia accumulate cholesterol intracellularly. We hypothesized that this sequestration of cholesterol in glia might restrict the availability of cholesterol for lipoprotein production. Cerebellar astroglia were cultured from a murine model of NPC disease to compare the lipoproteins generated by these cells and wild-type glia. The experiments demonstrate that the amount of cholesterol in glia-conditioned medium is not reduced by NPC1 deficiency. Similarly, cholesterol efflux to apo (apolipoprotein) A1 or glial expression of the transporter ATP-binding-cassette transporter A1 was not decreased by NPC1 deficiency. In addition, the ratio of apo E:cholesterol and the density distribution of lipoproteins in Npc1−/− and Npc1+/+ glia-conditioned medium are indistinguishable. Importantly, in a functional assay, apo E-containing lipoproteins generated by Npc1−/− and Npc1+/+ glia each stimulate axonal elongation of neurons by approx. 35%. On the basis of these observations, we speculate that the neuropathology characteristic of NPC disease can quite probably be ascribed to impaired processes within neurons in the brain rather than defective lipoprotein production by astroglia.
36
Cougnoux, Antony, Julia C. Yerger, Mason Fellmeth, Jenny Serra-Vinardell, Kyle Martin, Fatemeh Navid, James Iben, Christopher A. Wassif, Niamh X. Cawley, and Forbes D. Porter. "Single Cell Transcriptome Analysis of Niemann–Pick Disease, Type C1 Cerebella." International Journal of Molecular Sciences 21, no. 15 (July 28, 2020): 5368. http://dx.doi.org/10.3390/ijms21155368.
Full textAbstract:
Niemann–Pick disease, type C1 (NPC1) is a lysosomal disease characterized by endolysosomal storage of unesterified cholesterol and decreased cellular cholesterol bioavailability. A cardinal symptom of NPC1 is cerebellar ataxia due to Purkinje neuron loss. To gain an understanding of the cerebellar neuropathology we obtained single cell transcriptome data from control (Npc1+/+) and both three-week-old presymptomatic and seven-week-old symptomatic mutant (Npc1−/−) mice. In seven-week-old Npc1−/− mice, differential expression data was obtained for neuronal, glial, vascular, and myeloid cells. As anticipated, we observed microglial activation and increased expression of innate immunity genes. We also observed increased expression of innate immunity genes by other cerebellar cell types, including Purkinje neurons. Whereas neuroinflammation mediated by microglia may have both neuroprotective and neurotoxic components, the contribution of increased expression of these genes by non-immune cells to NPC1 pathology is not known. It is possible that dysregulated expression of innate immunity genes by non-immune cells is neurotoxic. We did not anticipate a general lack of transcriptomic changes in cells other than microglia from presymptomatic three-week-old Npc1−/− mice. This observation suggests that microglia activation precedes neuronal dysfunction. The data presented in this paper will be useful for generating testable hypotheses related to disease progression and Purkinje neurons loss as well as providing insight into potential novel therapeutic interventions.
37
Li, Jian, Maika S. Deffieu, Peter L. Lee, Piyali Saha, and Suzanne R. Pfeffer. "Glycosylation inhibition reduces cholesterol accumulation in NPC1 protein-deficient cells." Proceedings of the National Academy of Sciences 112, no. 48 (November 17, 2015): 14876–81. http://dx.doi.org/10.1073/pnas.1520490112.
Full textAbstract:
Lysosomes are lined with a glycocalyx that protects the limiting membrane from the action of degradative enzymes. We tested the hypothesis that Niemann-Pick type C 1 (NPC1) protein aids the transfer of low density lipoprotein-derived cholesterol across this glycocalyx. A prediction of this model is that cells will be less dependent upon NPC1 if their glycocalyx is decreased in density. Lysosome cholesterol content was significantly lower after treatment of NPC1-deficient human fibroblasts with benzyl-2-acetamido-2-deoxy-α-D-galactopyranoside, an inhibitor of O-linked glycosylation. Direct biochemical measurement of cholesterol showed that lysosomes purified from NPC1-deficient fibroblasts contained at least 30% less cholesterol when O-linked glycosylation was blocked. As an independent means to modify protein glycosylation, we used Chinese hamster ovary ldl-D cells defective in UDP-Gal/UDP-GalNAc 4-epimerase in which N- and O-linked glycosylation can be controlled. CRISPR generated, NPC1-deficient ldl-D cells supplemented with galactose accumulated more cholesterol than those in which sugar addition was blocked. In the absence of galactose supplementation, NPC1-deficient ldl-D cells also transported more cholesterol from lysosomes to the endoplasmic reticulum, as monitored by an increase in cholesteryl [14C]-oleate levels. These experiments support a model in which NPC1 protein functions to transfer cholesterol past a lysosomal glycocalyx.
38
Yu, Daozhan, Manju Swaroop, Mengqiao Wang, Ulrich Baxa, Rongze Yang, Yiping Yan, Turhan Coksaygan, et al. "Niemann–Pick Disease Type C." Journal of Biomolecular Screening 19, no. 8 (June 6, 2014): 1164–73. http://dx.doi.org/10.1177/1087057114537378.
Full textAbstract:
Niemann–Pick disease type C (NPC) is a rare neurodegenerative disorder caused by recessive mutations in the NPC1 or NPC2 gene that result in lysosomal accumulation of unesterified cholesterol in patient cells. Patient fibroblasts have been used for evaluation of compound efficacy, although neuronal degeneration is the hallmark of NPC disease. Here, we report the application of human NPC1 neural stem cells as a cell-based disease model to evaluate nine compounds that have been reported to be efficacious in the NPC1 fibroblasts and mouse models. These cells are differentiated from NPC1 induced pluripotent stem cells and exhibit a phenotype of lysosomal cholesterol accumulation. Treatment of these cells with hydroxypropyl-β-cyclodextrin, methyl-β-cyclodextrin, and δ-tocopherol significantly ameliorated the lysosomal cholesterol accumulation. Combined treatment with cyclodextrin and δ-tocopherol shows an additive or synergistic effect that otherwise requires 10-fold higher concentration of cyclodextrin alone. In addition, we found that hydroxypropyl-β-cyclodextrin is much more potent and efficacious in the NPC1 neural stem cells compared to the NPC1 fibroblasts. Miglustat, suberoylanilide hydroxamic acid, curcumin, lovastatin, pravastatin, and rapamycin did not, however, have significant effects in these cells. The results demonstrate that patient-derived NPC1 neural stem cells can be used as a model system for evaluation of drug efficacy and study of disease pathogenesis.
39
Newton, Jason, Elisa N. D. Palladino, Cynthia Weigel, Michael Maceyka, Markus H. Gräler, Can E. Senkal, Ricardo D. Enriz, et al. "Targeting defective sphingosine kinase 1 in Niemann–Pick type C disease with an activator mitigates cholesterol accumulation." Journal of Biological Chemistry 295, no. 27 (May 8, 2020): 9121–33. http://dx.doi.org/10.1074/jbc.ra120.012659.
Full textAbstract:
Niemann–Pick type C (NPC) disease is a lysosomal storage disorder arising from mutations in the cholesterol-trafficking protein NPC1 (95%) or NPC2 (5%). These mutations result in accumulation of low-density lipoprotein-derived cholesterol in late endosomes/lysosomes, disruption of endocytic trafficking, and stalled autophagic flux. Additionally, NPC disease results in sphingolipid accumulation, yet it is unique among the sphingolipidoses because of the absence of mutations in the enzymes responsible for sphingolipid degradation. In this work, we examined the cause for sphingosine and sphingolipid accumulation in multiple cellular models of NPC disease and observed that the activity of sphingosine kinase 1 (SphK1), one of the two isoenzymes that phosphorylate sphingoid bases, was markedly reduced in both NPC1 mutant and NPC1 knockout cells. Conversely, SphK1 inhibition with the isotype-specific inhibitor SK1-I in WT cells induced accumulation of cholesterol and reduced cholesterol esterification. Of note, a novel SphK1 activator (SK1-A) that we have characterized decreased sphingoid base and complex sphingolipid accumulation and ameliorated autophagic defects in both NPC1 mutant and NPC1 knockout cells. Remarkably, in these cells, SK1-A also reduced cholesterol accumulation and increased cholesterol ester formation. Our results indicate that a SphK1 activator rescues aberrant cholesterol and sphingolipid storage and trafficking in NPC1 mutant cells. These observations highlight a previously unknown link between SphK1 activity, NPC1, and cholesterol trafficking and metabolism.
40
Wang, Chao, Samantha M. Scott, Shuhong Sun, Pei Zhao, Darren M. Hutt, Hao Shao, Jason E. Gestwicki, and William E. Balch. "Individualized management of genetic diversity in Niemann-Pick C1 through modulation of the Hsp70 chaperone system." Human Molecular Genetics 29, no. 1 (September 11, 2019): 1–19. http://dx.doi.org/10.1093/hmg/ddz215.
Full textAbstract:
Abstract Genetic diversity provides a rich repository for understanding the role of proteostasis in the management of the protein fold in human biology. Failure in proteostasis can trigger multiple disease states, affecting both human health and lifespan. Niemann-Pick C1 (NPC1) disease is a rare genetic disorder triggered by mutations in NPC1, a multi-spanning transmembrane protein that is trafficked through the exocytic pathway to late endosomes (LE) and lysosomes (Ly) (LE/Ly) to globally manage cholesterol homeostasis. Defects triggered by >300 NPC1 variants found in the human population inhibit export of NPC1 protein from the endoplasmic reticulum (ER) and/or function in downstream LE/Ly, leading to cholesterol accumulation and onset of neurodegeneration in childhood. We now show that the allosteric inhibitor JG98, that targets the cytosolic Hsp70 chaperone/co-chaperone complex, can significantly improve the trafficking and post-ER protein level of diverse NPC1 variants. Using a new approach to model genetic diversity in human disease, referred to as variation spatial profiling, we show quantitatively how JG98 alters the Hsp70 chaperone/co-chaperone system to adjust the spatial covariance (SCV) tolerance and set-points on an amino acid residue-by-residue basis in NPC1 to differentially regulate variant trafficking, stability, and cholesterol homeostasis, results consistent with the role of BCL2-associated athanogene family co-chaperones in managing the folding status of NPC1 variants. We propose that targeting the cytosolic Hsp70 system by allosteric regulation of its chaperone/co-chaperone based client relationships can be used to adjust the SCV tolerance of proteostasis buffering capacity to provide an approach to mitigate systemic and neurological disease in the NPC1 population.
41
Davidson, Cristin D., Alana L. Gibson, Tansy Gu, Laura L. Baxter, Benjamin E. Deverman, Keith Beadle, Arturo A. Incao, et al. "Improved systemic AAV gene therapy with a neurotrophic capsid in Niemann–Pick disease type C1 mice." Life Science Alliance 4, no. 10 (August 18, 2021): e202101040. http://dx.doi.org/10.26508/lsa.202101040.
Full textAbstract:
Niemann–Pick C1 disease (NPC1) is a rare, fatal neurodegenerative disease caused by mutations in NPC1, which encodes the lysosomal cholesterol transport protein NPC1. Disease pathology involves lysosomal accumulation of cholesterol and lipids, leading to neurological and visceral complications. Targeting the central nervous system (CNS) from systemic circulation complicates treatment of neurological diseases with gene transfer techniques. Selected and engineered capsids, for example, adeno-associated virus (AAV)-PHP.B facilitate peripheral-to-CNS transfer and hence greater CNS transduction than parental predecessors. We report that systemic delivery to Npc1m1N/m1N mice using an AAV-PHP.B vector ubiquitously expressing NPC1 led to greater disease amelioration than an otherwise identical AAV9 vector. In addition, viral copy number and biodistribution of GFP-expressing reporters showed that AAV-PHP.B achieved more efficient, albeit variable, CNS transduction than AAV9 in Npc1m1N/m1N mice. This variability was associated with segregation of two alleles of the putative AAV-PHP.B receptor Ly6a in Npc1m1N/m1N mice. Our data suggest that robust improvements in NPC1 disease phenotypes occur even with modest CNS transduction and that improved neurotrophic capsids have the potential for superior NPC1 AAV gene therapy vectors.
42
Hodošček, Milan, and Nadia Elghobashi-Meinhardt. "Simulations of NPC1(NTD):NPC2 Protein Complex Reveal Cholesterol Transfer Pathways." International Journal of Molecular Sciences 19, no. 9 (September 4, 2018): 2623. http://dx.doi.org/10.3390/ijms19092623.
Full textAbstract:
The Niemann Pick type C (NPC) proteins, NPC1 and NPC2, are involved in the lysosomal storage disease, NPC disease. The formation of a NPC1–NPC2 protein–protein complex is believed to be necessary for the transfer of cholesterol and lipids out of the late endosomal (LE)/lysosomal (Lys) compartments. Mutations in either NPC1 or NPC2 can lead to an accumulation of cholesterol and lipids in the LE/Lys, the primary phenotype of the NPC disease. We investigated the NPC1(NTD)–NPC2 protein–protein complex computationally using two putative binding interfaces. A combination of molecular modeling and molecular dynamics simulations reveals atomic details that are responsible for interface stability. Cholesterol binding energies associated with each of the binding pockets for the two models are calculated. Analyses of the cholesterol binding in the two models support bidirectional ligand transfer when a particular interface is established. Based on the results, we propose that, depending on the location of the cholesterol ligand, a dynamical interface between the NPC2 and NPC1(NTD) proteins exists. Structural features of a particular interface can lower the energy barrier and stabilize the passage of the cholesterol substrate from NPC2 to NPC1(NTD).
43
Du, Ximing, Jaspal Kumar, Charles Ferguson, Timothy A. Schulz, Yan Shan Ong, Wanjin Hong, William A. Prinz, Robert G. Parton, Andrew J. Brown, and Hongyuan Yang. "A role for oxysterol-binding protein–related protein 5 in endosomal cholesterol trafficking." Journal of Cell Biology 192, no. 1 (January 10, 2011): 121–35. http://dx.doi.org/10.1083/jcb.201004142.
Full textAbstract:
Oxysterol-binding protein (OSBP) and its related proteins (ORPs) constitute a large and evolutionarily conserved family of lipid-binding proteins that target organelle membranes to mediate sterol signaling and/or transport. Here we characterize ORP5, a tail-anchored ORP protein that localizes to the endoplasmic reticulum. Knocking down ORP5 causes cholesterol accumulation in late endosomes and lysosomes, which is reminiscent of the cholesterol trafficking defect in Niemann Pick C (NPC) fibroblasts. Cholesterol appears to accumulate in the limiting membranes of endosomal compartments in ORP5-depleted cells, whereas depletion of NPC1 or both ORP5 and NPC1 results in luminal accumulation of cholesterol. Moreover, trans-Golgi resident proteins mislocalize to endosomal compartments upon ORP5 depletion, which depends on a functional NPC1. Our results establish the first link between NPC1 and a cytoplasmic sterol carrier, and suggest that ORP5 may cooperate with NPC1 to mediate the exit of cholesterol from endosomes/lysosomes.
44
O’Neill, Kathleen. "Triple Negative Breast Cancer is Dependent on the Lysosomal Cholesterol Transporter NPC1." Journal of the Endocrine Society 5, Supplement_1 (May 1, 2021): A1034. http://dx.doi.org/10.1210/jendso/bvab048.2116.
Full textAbstract:
Abstract Background: Triple Negative Breast Cancer (TNBC) is an aggressive subtype of breast cancer (BC) with peak rate of metastasis within the first few years post diagnosis and few targeted therapies. Normal epithelial cells and estrogen receptor alpha (ER) positive BC express the microRNA-200c (miR-200c), a potent suppressor of epithelial-to-mesenchymal transition (EMT). However, miR-200c is silenced or lost in TNBC, allowing aberrant expression of genes conferring a de-differentiated, non-epithelial phenotype that confers invasive and chemo-resistant properties. Recent literature demonstrated that EMT also promotes altered tumor cell metabolism. Hypothesis: We postulate that EMT reversal in TNBC will reveal selective advantages and identify novel therapeutic vulnerabilities. Methods: We used restoration of miR-200c as a tool to identify selective advantages conferred by EMT. In addition to driving global metabolic changes, miR-200c-repressed key cholesterol metabolism genes that support the uptake of dietary cholesterol, which is delivered via low-density-lipoproteins (LDL) and processed by the lysosomal cholesterol transporter, Niemann-Pick Type C1 (NPC1). Manipulation of NPC1 by genetic and pharmacological means was used to determine if and how TNBC are reliant on this pathway. Results: We determined that NPC1 is overexpressed in TNBC relative to ER+BC (Nature Metabric P<0.0001). Restoration of miR-200c directly targets the NPC1 3’UTR and represses NPC1 by two-fold (p=0.01). While silencing of NPC1 in ER+ BC cells led to slowed proliferation, TNBC cell lines died within 48-72 hours. NPC1 is associated with mitochondrial dysfunction and mTOR suppression. Intracellular cholesterol homeostasis is critical for cell survival and is carefully regulated, but how these homeostatic mechanisms adapt during tumor progression is poorly understood. Conclusions: This study demonstrates that while mesenchymal-like TNBC cells do not require exogenous cholesterol from the microenvironment, this cancer type is sensitive to the loss of NPC1. Overall, this work identifies NPC1 as a novel target in TNBC and sheds light on how lysosomes and mitochondria interact to sense cholesterol and drive cell survival.
45
Chen, Fannie W., Ronald E. Gordon, and Yiannis A. Ioannou. "NPC1 late endosomes contain elevated levels of non-esterified (‘free’) fatty acids and an abnormally glycosylated form of the NPC2 protein." Biochemical Journal 390, no. 2 (August 23, 2005): 549–61. http://dx.doi.org/10.1042/bj20050236.
Full textAbstract:
NPC (Niemann–Pick type C) disease is a rare lipidosis characterized by the accumulation of LDL (low-density lipoprotein)-derived non-esterified cholesterol in the E/L (endosomal/lysosomal) system. The gene products that are responsible for the two NPC complementation groups are distinct and dissimilar, yet their cellular and disease phenotypes are virtually indistinguishable. To investigate the relationship between NPC1 and NPC2 and their potential role in NPC disease pathogenesis, we have developed a method for the rapid and efficient isolation of late endocytic vesicles from mouse liver by magnetic chromatography. Late endosomes from Wt (wild-type) and NPC1 mice were found to differ not only in their cholesterol and sphingomyelin content, as expected, but also in their non-esterified (‘free’) fatty acid content, with NPC1 vesicles showing an approx. 7-fold increase in non-esterified fatty acid levels compared with Wt vesicles. Furthermore, we show that the NPC2 protein is in an incompletely deglycosylated form in NPC1 late endosomes by a mechanism that is specific to the NPC2 protein and not a global aberration of protein glycosylation/deglycosylation or trafficking, since NPC2 secreted from NPC1 cells is indistinguishable from that secreted from Wt cells. Also, a greater proportion of the normally soluble cellular NPC2 protein partitions with detergent-insoluble late endosomal internal membrane domains in NPC1 vesicles. In addition, we show that, although a small amount of the NPC2 protein associates with these membranes in Wt vesicles, this localization becomes much more pronounced in NPC1 vesicles. These results suggest that the function of the NPC2 protein may be compromised as well in NPC1 endosomes, which might explain the paradoxical phenotypic similarities of the two NPC disease complementation groups.
46
Tiscione, Scott A., Oscar Vivas, Kenneth S. Ginsburg, Donald M. Bers, Daniel S. Ory, Luis F. Santana, Rose E. Dixon, and Eamonn J. Dickson. "Disease-associated mutations in Niemann-Pick type C1 alter ER calcium signaling and neuronal plasticity." Journal of Cell Biology 218, no. 12 (October 10, 2019): 4141–56. http://dx.doi.org/10.1083/jcb.201903018.
Full textAbstract:
Niemann-Pick type C1 (NPC1) protein is essential for the transport of externally derived cholesterol from lysosomes to other organelles. Deficiency of NPC1 underlies the progressive NPC1 neurodegenerative disorder. Currently, there are no curative therapies for this fatal disease. Given the Ca2+ hypothesis of neurodegeneration, which posits that altered Ca2+ dynamics contribute to neuropathology, we tested if disease mutations in NPC1 alter Ca2+ signaling and neuronal plasticity. We determine that NPC1 inhibition or disease mutations potentiate store-operated Ca2+ entry (SOCE) due to a presenilin 1 (PSEN1)–dependent reduction in ER Ca2+ levels alongside elevated expression of the molecular SOCE components ORAI1 and STIM1. Associated with this dysfunctional Ca2+ signaling is destabilization of neuronal dendritic spines. Knockdown of PSEN1 or inhibition of the SREBP pathway restores Ca2+ homeostasis, corrects differential protein expression, reduces cholesterol accumulation, and rescues spine density. These findings highlight lysosomes as a crucial signaling platform responsible for tuning ER Ca2+ signaling, SOCE, and synaptic architecture in health and disease.
47
Kondoh, Tatsunari, Michael Letko, Vincent J. Munster, Rashid Manzoor, Junki Maruyama, Wakako Furuyama, Hiroko Miyamoto, et al. "Single-Nucleotide Polymorphisms in Human NPC1 Influence Filovirus Entry Into Cells." Journal of Infectious Diseases 218, suppl_5 (July 14, 2018): S397—S402. http://dx.doi.org/10.1093/infdis/jiy248.
Full textAbstract:
Abstract Niemann-Pick C1 (NPC1), a host receptor involved in the envelope glycoprotein (GP)–mediated entry of filoviruses into cells, is believed to be a major determinant of cell susceptibility to filovirus infection. It is known that proteolytically digested Ebola virus (EBOV) GP interacts with 2 protruding loops in domain C of NPC1. Using previously published structural data and the National Center for Biotechnology Information Single-Nucleotide Polymorphism (SNP) database, we identified 10 naturally occurring missense SNPs in human NPC1. To investigate whether these SNPs affect cell susceptibility to filovirus infection, we generated Vero E6 cell lines stably expressing NPC1 with SNP substitutions and compared their susceptibility to vesicular stomatitis virus pseudotyped with filovirus GPs and infectious EBOV. We found that some of the substitutions resulted in reduced susceptibility to filoviruses, as indicated by the lower titers and smaller plaque/focus sizes of the viruses. Our data suggest that human NPC1 SNPs may likely affect host susceptibility to filoviruses.
48
Li, Xiaochun, Jiawei Wang, Elias Coutavas, Hang Shi, Qi Hao, and Günter Blobel. "Structure of human Niemann–Pick C1 protein." Proceedings of the National Academy of Sciences 113, no. 29 (June 15, 2016): 8212–17. http://dx.doi.org/10.1073/pnas.1607795113.
Full textAbstract:
Niemann–Pick C1 protein (NPC1) is a late-endosomal membrane protein involved in trafficking of LDL-derived cholesterol, Niemann–Pick disease type C, and Ebola virus infection. NPC1 contains 13 transmembrane segments (TMs), five of which are thought to represent a “sterol-sensing domain” (SSD). Although present also in other key regulatory proteins of cholesterol biosynthesis, uptake, and signaling, the structure and mechanism of action of the SSD are unknown. Here we report a crystal structure of a large fragment of human NPC1 at 3.6 Å resolution, which reveals internal twofold pseudosymmetry along TM 2–13 and two structurally homologous domains that protrude 60 Å into the endosomal lumen. Strikingly, NPC1's SSD forms a cavity that is accessible from both the luminal bilayer leaflet and the endosomal lumen; computational modeling suggests that this cavity is large enough to accommodate one cholesterol molecule. We propose a model for NPC1 function in cholesterol sensing and transport.
49
Fukaura, Madoka, Yoichi Ishitsuka, Seiichi Shirakawa, Naoki Ushihama, Yusei Yamada, Yuki Kondo, Toru Takeo, et al. "Intracerebroventricular Treatment with 2-Hydroxypropyl-β-Cyclodextrin Decreased Cerebellar and Hepatic Glycoprotein Nonmetastatic Melanoma Protein B (GPNMB) Expression in Niemann–Pick Disease Type C Model Mice." International Journal of Molecular Sciences 22, no. 1 (January 5, 2021): 452. http://dx.doi.org/10.3390/ijms22010452.
Full textAbstract:
Niemann–Pick disease type C (NPC) is a recessive hereditary disease caused by mutation of the NPC1 or NPC2 gene. It is characterized by abnormality of cellular cholesterol trafficking with severe neuronal and hepatic injury. In this study, we investigated the potential of glycoprotein nonmetastatic melanoma protein B (GPNMB) to act as a biomarker reflecting the therapeutic effect of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) in an NPC mouse model. We measured serum, brain, and liver expression levels of GPNMB, and evaluated their therapeutic effects on NPC manifestations in the brain and liver after the intracerebroventricular administration of HP-β-CD in Npc1 gene-deficient (Npc1−/−) mice. Intracerebroventricular HP-β-CD inhibited cerebellar Purkinje cell damage in Npc1−/− mice and significantly reduced serum and cerebellar GPNMB levels. Interestingly, we also observed that the intracerebral administration significantly reduced hepatic GPNMB expression and elevated serum ALT in Npc1−/− mice. Repeated doses of intracerebroventricular HP-β-CD (30 mg/kg, started at 4 weeks of age and repeated every 2 weeks) drastically extended the lifespan of Npc1−/− mice compared with saline treatment. In summary, our results suggest that GPNMB level in serum is a potential biomarker for evaluating the attenuation of NPC pathophysiology by intracerebroventricular HP-β-CD treatment.
50
Cianciola, Nicholas L., Diane J. Greene, Richard E. Morton, and Cathleen R. Carlin. "Adenovirus RIDα uncovers a novel pathway requiring ORP1L for lipid droplet formation independent of NPC1." Molecular Biology of the Cell 24, no. 21 (November 2013): 3309–25. http://dx.doi.org/10.1091/mbc.e12-10-0760.
Full textAbstract:
Niemann–Pick disease type C (NPC) is caused by mutations in NPC1 or NPC2, which coordinate egress of low-density-lipoprotein (LDL)-cholesterol from late endosomes. We previously reported that the adenovirus-encoded protein RIDα rescues the cholesterol storage phenotype in NPC1-mutant fibroblasts. We show here that RIDα reconstitutes deficient endosome-to-endoplasmic reticulum (ER) transport, allowing excess LDL-cholesterol to be esterified by acyl-CoA:cholesterol acyltransferase and stored in lipid droplets (LDs) in NPC1-deficient cells. Furthermore, the RIDα pathway is regulated by the oxysterol-binding protein ORP1L. Studies have classified ORP1L as a sterol sensor involved in LE positioning downstream of GTP-Rab7. Our data, however, suggest that ORP1L may play a role in transport of LDL-cholesterol to a specific ER pool designated for LD formation. In contrast to NPC1, which is dispensable, the RIDα/ORP1L-dependent route requires functional NPC2. Although NPC1/NPC2 constitutes the major pathway, therapies that amplify minor egress routes for LDL-cholesterol could significantly improve clinical management of patients with loss-of-function NPC1 mutations. The molecular identity of putative alternative pathways, however, is poorly characterized. We propose RIDα as a model system for understanding physiological egress routes that use ORP1L to activate ER feedback responses involved in LD formation.