scholarly journals Sorting of an internalized plasma membrane lipid between recycling and degradative pathways in normal and Niemann-Pick, type A fibroblasts.

1990 ◽  
Vol 111 (2) ◽  
pp. 429-442 ◽  
Author(s):  
M Koval ◽  
R E Pagano
Keyword(s):  
Plasma Membrane ◽  
Intracellular Transport ◽  
Type A ◽  
Membrane Lipid ◽  
Acid Sphingomyelinase ◽  
Human Skin Fibroblast ◽  
Membrane Recycling ◽  
Degradative Pathway ◽  
Intracellular Compartments ◽  
Niemann Pick

We examined the metabolism and intracellular transport of a fluorescent sphingomyelin analogue, N-(N-[6-[(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]caproyl])- sphingosylphosphorylcholine (C6-NBD-SM), in both normal and Niemann-Pick, type A (NP-A) human skin fibroblast monolayers. C6-NBD-SM was integrated into the plasma membrane bilayer by transfer of C6-NBD-SM monomers from liposomes to cells at 7 degrees C. The cells were washed, and within 3 min of warming to 37 degrees C, both normal and NP-A fibroblasts had internalized C6-NBD-SM from the plasma membrane, resulting in a punctate pattern of intracellular fluorescence. Rates for C6-NBD-SM internalization and transport from intracellular compartments to the plasma membrane (recycling) were similar for normal and NP-A cells. With increasing time at 37 degrees C, internalized C6-NBD-SM accumulated in the lysosomes of NP-A fibroblasts, while normal fibroblasts showed increasing Golgi apparatus fluorescence with no observable lysosomal labeling. Since NP-A fibroblasts lack lysosomal (acid) sphingomyelinase (A-SMase), this result suggested that hydrolysis of C6-NBD-SM prevented its accumulation in the lysosomes of normal fibroblasts during its transport along the degradative pathway. We used the amount of C6-NBD-SM hydrolysis by A-SMase in normal cells as a measure of C6-NBD-SM transported from the cell surface to the lysosomes. After a lag period, C6-NBD-SM was delivered to the lysosomes at a rate of approximately 8%/h. This rate was approximately 18-19 fold slower than the rate of C6-NBD-SM recycling from intracellular compartments to the plasma membrane. Thus, small amounts of C6-NBD-SM were transported along the degradative pathway, while most endocytosed C6-NBD-SM was sorted for transport along the plasma membrane recycling pathway.

scholarly journals Lipid recycling between the plasma membrane and intracellular compartments: transport and metabolism of fluorescent sphingomyelin analogues in cultured fibroblasts.

1989 ◽  
Vol 108 (6) ◽  
pp. 2169-2181 ◽  
Author(s):  
M Koval ◽  
R E Pagano
Keyword(s):  
Plasma Membrane ◽  
Intracellular Transport ◽  
Chinese Hamster ◽  
Membrane Lipid ◽  
Cell Periphery ◽  
Perinuclear Region ◽  
Cultured Fibroblasts ◽  
Plasma Membrane Lipid ◽  
Intracellular Compartments ◽  
Fluorescent Lipid

We examined the metabolism and intracellular transport of the D-erythro and L-threo stereoisomers of a fluorescent analogue of sphingomyelin, N-(N-[6-[(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino] caproyl])-sphingosylphosphorylcholine (C6-NBD-SM), in Chinese hamster ovary (CHO-K1) fibroblast monolayers. C6-NBD-SM was integrated into the plasma membrane bilayer by transfer of C6-NBD-SM monomers from liposomes to cells at 7 degrees C. The cells were washed, and within 10-15 min of being warmed to 37 degrees C, C6-NBD-SM was internalized from the plasma membrane to a perinuclear location that colocalized with the centriole and was distinct from the lysosomes and the Golgi apparatus. This perinuclear region was also labeled by internalized rhodamine-conjugated transferrin. C6-NBD-SM endocytosis was not inhibited when the microtubules were disrupted with nocodazole; rather, the fluorescent lipid was distributed in vesicles throughout the cell periphery instead of being internalized to the perinuclear region of the cell. The metabolism of C6-NBD-SM to other fluorescent sphingolipids at 37 degrees C and its effect on C6-NBD-SM transport was also examined. To study plasma membrane lipid recycling, C6-NBD-SM was first inserted into the plasma membrane of CHO-K1 cells and then allowed to be internalized by the cells at 37 degrees C. Any C6-NBD-SM remaining at the plasma membrane was then removed by incubation with nonfluorescent liposomes at 7 degrees C, leaving cells containing only internalized fluorescent lipid. The return of C6-NBD-SM to the plasma membrane from intracellular compartments upon further 37 degrees C incubation was then observed. The half-time for a complete round C6-NBD-SM recycling between the plasma membrane and intracellular compartments was approximately 40 min. Pretreatment of cells with either monensin or nocodazole did not inhibit C6-NBD-SM recycling.

Depletion of rafts in late endocytic membranes is controlled by NPC1-dependent recycling of cholesterol to the plasma membrane

2001 ◽  
Vol 114 (10) ◽  
pp. 1893-1900 ◽  
Author(s):  
S. Lusa ◽  
T.S. Blom ◽  
E.L. Eskelinen ◽  
E. Kuismanen ◽  
J.E. Mansson ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Interactions ◽  
Mammalian Cells ◽  
Intracellular Transport ◽  
Ldl Cholesterol ◽  
Normal Cells ◽  
Recycling Endosomes ◽  
Regulate Protein ◽  
Niemann Pick ◽  
Accumulation Characteristic

In mammalian cells, cholesterol is thought to associate with sphingolipids to form lateral membrane domains termed rafts. Increasing evidence suggests that rafts regulate protein interactions, for example, during signalling, intracellular transport and host-pathogen interactions. Rafts are present in cholesterol-sphingolipid-enriched membranes, including early and recycling endosomes, but whether rafts are found in late endocytic organelles has not been analyzed. In this study, we analyzed the association of cholesterol and late endosomal proteins with low-density detergent-resistant membranes (DRMs) in normal cells and in cells with lysosomal cholesterol-sphingolipid accumulation. In normal cells, the majority of [(3)H]cholesterol released from [(3)H]cholesterol ester-LDL associated with detergent-soluble membranes, was rapidly transported to the plasma membrane and became increasingly insoluble with time. In Niemann-Pick C1 (NPC1) protein-deficient lipidosis cells, the association of LDL-cholesterol with DRMs was enhanced and its transport to the plasma membrane was inhibited. In addition, the NPC1 protein was normally recovered in detergent-soluble membranes and its association with DRMs was enhanced by lysosomal cholesterol loading. Moreover, lysosomal cholesterol deposition was kinetically paralleled by the sequestration of sphingolipids and formation of multilamellar bodies in late endocytic organelles. These results suggest that late endocytic organelles are normally raft-poor and that endocytosed LDL-cholesterol is efficiently recycled to the plasma membrane in an NPC1-dependent process. The cholesterol-sphingolipid accumulation characteristic to NPC disease, and potentially to other sphingolipidoses, causes an overcrowding of rafts forming lamellar bodies in the degradative compartments.

scholarly journals Niemann-Pick Type A Disease: Behavior of Neutral Sphingomyelinase and Vitamin D Receptor

2019 ◽  
Vol 20 (9) ◽  
pp. 2365 ◽  
Author(s):  
Carmela Conte ◽  
Cataldo Arcuri ◽  
Samuela Cataldi ◽  
Carmen Mecca ◽  
Michela Codini ◽  
...  
Keyword(s):  
Vitamin D ◽  
Vitamin D Receptor ◽  
Synapse Formation ◽  
Type A ◽  
Acid Sphingomyelinase ◽  
Vdr Gene ◽  
Neutral Sphingomyelinase ◽  
Protein Levels ◽  
Gene And Protein Expression ◽  
Niemann Pick

Sphingomyelinase (SMase) is responsible for the breakdown of sphingomyelin (SM) with production of ceramide. The absence of acid sphingomyelinase (aSMase) causes abnormal synapse formation in Niemann-Pick type A (NPA) disease. Because high levels of ceramide in the NPA brain were demonstrated, the involvement of other SMases were supposed. In the present study we focused the attention on the neurogenic niches in the hippocampal gyrus dentatus (GD), a brain structure essential for forming cohesive memory. We demonstrated for the first time the increase of (Sex determining region Y)-box 2 (SOX2), and the down-regulation of glial fibrillary acidic protein (GFAP) NPA mice GD. Moreover, we found that the expression of Toll like receptors (TLRs), was increased in NPA mice, particularly TLR2, TLR7, TLR8 and TLR9 members. Although no significant change in neutral sphingomyelinase (nSMase) gene expression was detected in the NPA mice hippocampus of, protein levels were enhanced, probably because of the slower protein degradation rate in this area. Many studies demonstrated that vitamin D receptor (VDR) is expressed in the hippocampus GD. Unexpectedly, we showed that NPA mice exhibited VDR gene and protein expression up-regulation. In summary, our study suggests a relation between hippocampal cell differentiation defect, nSMase and VDR increase in NPA mice.

scholarly journals Exocytosis of acid sphingomyelinase by wounded cells promotes endocytosis and plasma membrane repair

2010 ◽  
Vol 189 (6) ◽  
pp. 1027-1038 ◽  
Author(s):  
Christina Tam ◽  
Vincent Idone ◽  
Cecilia Devlin ◽  
Maria Cecilia Fernandes ◽  
Andrew Flannery ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Lysosomal Enzyme ◽  
Membrane Integrity ◽  
Acid Sphingomyelinase ◽  
Membrane Repair ◽  
Membrane Injury ◽  
Cellular Survival ◽  
Plasma Membrane Repair ◽  
Membrane Resealing ◽  
Niemann Pick

Rapid plasma membrane resealing is essential for cellular survival. Earlier studies showed that plasma membrane repair requires Ca2+-dependent exocytosis of lysosomes and a rapid form of endocytosis that removes membrane lesions. However, the functional relationship between lysosomal exocytosis and the rapid endocytosis that follows membrane injury is unknown. In this study, we show that the lysosomal enzyme acid sphingomyelinase (ASM) is released extracellularly when cells are wounded in the presence of Ca2+. ASM-deficient cells, including human cells from Niemann-Pick type A (NPA) patients, undergo lysosomal exocytosis after wounding but are defective in injury-dependent endocytosis and plasma membrane repair. Exogenously added recombinant human ASM restores endocytosis and resealing in ASM-depleted cells, suggesting that conversion of plasma membrane sphingomyelin to ceramide by this lysosomal enzyme promotes lesion internalization. These findings reveal a molecular mechanism for restoration of plasma membrane integrity through exocytosis of lysosomes and identify defective plasma membrane repair as a possible component of the severe pathology observed in NPA patients.

scholarly journals Identification and expression of a common missense mutation (L302P) in the acid sphingomyelinase gene of Ashkenazi Jewish type A Niemann-Pick disease patients

Blood ◽  
1992 ◽  
Vol 80 (8) ◽  
pp. 2081-2087 ◽  
Author(s):  
O Levran ◽  
RJ Desnick ◽  
EH Schuchman
Keyword(s):  
Missense Mutation ◽  
Neurodegenerative Disorder ◽  
Type A ◽  
Acid Sphingomyelinase ◽  
Common Mutation ◽  
Ashkenazi Jewish ◽  
Type B ◽  
Niemann Pick Disease ◽  
Niemann Pick ◽  
Pick Disease

Abstract Types A and B Niemann-Pick disease (NPD) result from the deficient activity of acid sphingomyelinase (ASM; E.C. 3.1.4.12) and the resultant lysosomal accumulation of sphingomyelin. Type A disease is a fatal, neurodegenerative disorder of infancy, whereas type B disease has no neurologic manifestations and is characterized primarily by reticuloendothelial involvement and survival into adulthood. Both disorders occur more frequently among individuals of Ashkenazi Jewish ancestry than in the general population. Recently, a missense mutation in the ASM gene (designated R496L) was detected in more than 30% of the ASM alleles from Ashkenazi Jewish type A NPD patients. We report a second, common mutation that resulted from a T to C transition at nucleotide 905 and predicted a leucine to proline substitution at ASM codon 302 (designated L302P). Notably, the L302P mutation occurred in 23.5% (8 of 34) of the Ashkenazi Jewish type A NPD alleles studied. In contrast, it was not found in any of the ASM alleles from non-Jewish type A patients, in 36 alleles from type B patients, or in 100 ASM alleles from normal Ashkenazi Jewish individuals. To confirm the authenticities of the L302P and R496L mutations, each nucleotide change was separately introduced into the full-length ASM cDNA by site- directed mutagenesis and transiently expressed in COS-1 cells. Neither mutation expressed ASM catalytic activity, consistent with the type A phenotype of homoallelic patients. The identification of the L302P mutation should further facilitate molecular carrier detection for NPD in the Ashkenazi Jewish population, particularly because the L302P mutation can be easily detected using the restriction enzyme, AlwNl.

scholarly journals Adeno-associated viral vector serotype 9–based gene therapy for Niemann-Pick disease type A

2019 ◽  
Vol 11 (506) ◽  
pp. eaat3738 ◽  
Author(s):  
Lluis Samaranch ◽  
Azucena Pérez-Cañamás ◽  
Beatriz Soto-Huelin ◽  
Vivek Sudhakar ◽  
Jerónimo Jurado-Arjona ◽  
...  
Keyword(s):  
Mouse Model ◽  
Viral Vector ◽  
Type A ◽  
Disease Type ◽  
Acid Sphingomyelinase ◽  
Lysosomal Storage ◽  
Loss Of Function ◽  
Niemann Pick Disease ◽  
Niemann Pick ◽  
Pick Disease

Niemann-Pick disease type A (NPD-A) is a lysosomal storage disorder characterized by neurodegeneration and early death. It is caused by loss-of-function mutations in the gene encoding for acid sphingomyelinase (ASM), which hydrolyzes sphingomyelin into ceramide. Here, we evaluated the safety of cerebellomedullary (CM) cistern injection of adeno-associated viral vector serotype 9 encoding human ASM (AAV9-hASM) in nonhuman primates (NHP). We also evaluated its therapeutic benefit in a mouse model of the disease (ASM-KO mice). We found that CM injection in NHP resulted in widespread transgene expression within brain and spinal cord cells without signs of toxicity. CM injection in the ASM-KO mouse model resulted in hASM expression in cerebrospinal fluid and in different brain areas without triggering an inflammatory response. In contrast, direct cerebellar injection of AAV9-hASM triggered immune response. We also identified a minimally effective therapeutic dose for CM injection of AAV9-hASM in mice. Two months after administration, the treatment prevented motor and memory impairment, sphingomyelin (SM) accumulation, lysosomal enlargement, and neuronal death in ASM-KO mice. ASM activity was also detected in plasma from AAV9-hASM CM-injected ASM-KO mice, along with reduced SM amount and decreased inflammation in the liver. Our results support CM injection for future AAV9-based clinical trials in NPD-A as well as other lysosomal storage brain disorders.

scholarly journals Anomalous Surface Distribution of Glycosyl Phosphatidyl Inositol–anchored Proteins in Neurons Lacking Acid Sphingomyelinase

2008 ◽  
Vol 19 (2) ◽  
pp. 509-522 ◽  
Author(s):  
Cristian Galvan ◽  
Paola G. Camoletto ◽  
Flavio Cristofani ◽  
Paul P. Van Veldhoven ◽  
Maria Dolores Ledesma
Keyword(s):  
Plasma Membrane ◽  
Molecular Mechanisms ◽  
Phosphatidyl Inositol ◽  
Acid Sphingomyelinase ◽  
Wild Type ◽  
Surface Distribution ◽  
Lysosomal Disorder ◽  
Anomalous Surface ◽  
Membrane Attachment ◽  
Niemann Pick

Acid sphingomyelinase (ASM) converts sphingomyelin (SM) into ceramide. Mutations in the ASM gene cause the mental retardation syndrome Niemann Pick type A (NPA), characterized as a lysosomal disorder because of the SM accumulation in these organelles. We here report that neurons from mice lacking ASM (ASMKO) present increased plasma membrane SM levels evident in detergent-resistant membranes. Paralleling this lipidic alteration, GPI-anchored proteins show an aberrant distribution in both axons and dendrites instead of the axonal enrichment observed in neurons from wild-type mice. Trafficking analysis suggests that this is due to defective internalization from dendrites. Increasing the SM content in wild-type neurons mimics these defects, whereas SM reduction in ASMKO neurons prevents their occurrence. Moreover, expression of active RhoA, which membrane attachment is affected by SM accumulation, rescues internalization rates in ASMKO neurons. These data unveil an unexpected role for ASM in neuronal plasma membrane organization and trafficking providing insight on the molecular mechanisms involved. They also suggest that deficiencies in such processes could be key pathological events in NPA disease.

scholarly journals Alterations of myelin-specific proteins and sphingolipids characterize the brains of acid sphingomyelinase-deficient mice, an animal model of Niemann-Pick disease type A

2009 ◽  
Vol 109 (1) ◽  
pp. 105-115 ◽  
Author(s):  
Barbara Buccinnà ◽  
Marco Piccinini ◽  
Alessandro Prinetti ◽  
Federica Scandroglio ◽  
Simona Prioni ◽  
...  
Keyword(s):  
Animal Model ◽  
Type A ◽  
Disease Type ◽  
Acid Sphingomyelinase ◽  
Niemann Pick Disease ◽  
Specific Proteins ◽  
Niemann Pick ◽  
Deficient Mice ◽  
Pick Disease

scholarly journals Diverse chemical compounds target Plasmodium falciparum plasma membrane lipid homeostasis

2018 ◽  
Author(s):  
Suyash Bhatnagar ◽  
Sezin Nicklas ◽  
Joanne M. Morrisey ◽  
Daniel E. Goldberg ◽  
Akhil B. Vaidya
Keyword(s):  
Plasmodium Falciparum ◽  
Plasma Membrane ◽  
Lipid Composition ◽  
Chemical Compounds ◽  
Membrane Lipid ◽  
Lipid Homeostasis ◽  
Membrane Lipid Composition ◽  
Plasma Membrane Lipid ◽  
Elevated Cholesterol ◽  
Niemann Pick

AbstractLipid homeostasis is essential for the maintenance of life. We previously reported that disruptions of the parasite Na+ homeostasis via inhibition of PfATP4 resulted in elevated cholesterol within the parasite plasma membrane as assessed by saponin sensitivity. A large number of compounds have been shown to target the parasite Na+ homeostasis. We therefore screened the same collection of 800 compounds to identify chemotypes that disrupted the parasite plasma membrane lipid homeostasis. Here, we show that the compounds disrupting parasite Na+ homeostasis also induced saponin sensitivity, an indication of parasite lipid homeostasis disruption. Remarkably, 13 compounds were identified that altered plasma membrane lipid composition independent of Na+ homeostasis disruption. Further studies suggest that these compounds target the Plasmodium falciparum Niemann-Pick Type C1-Related (PfNCR1) protein, which is hypothesized to be involved in maintaining plasma membrane lipid composition. PfNCR1, like PfATP4, appears to be targeted by multiple chemotypes with potential for drug discovery.

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