scholarly journals Enhanced Stability of Non-Canonical NPC2 in the symbiosome supports coral-algal symbiosis

2018 ◽  
Author(s):  
Elizabeth A. Hambleton ◽  
Victor A.S. Jones ◽  
Ira Maegele ◽  
David K vaskoff ◽  
Timo Sachsenheimer ◽  
...  
Keyword(s):  
Low Ph ◽  
Nutrient Transfer ◽  
Cholesterol Trafficking ◽  
Pharmacological Inhibition ◽  
Algal Symbiosis ◽  
Specific Expansion ◽  
Niemann Pick ◽  
Enhanced Stability ◽  
Over Time ◽  
Sterol Trafficking

AbstractCnidarians such as reef-building corals depend upon nutrient transfer from intracellular symbionts, but the mechanisms and evolution of this process remain unknown. Homologues of the conserved cholesterol binder Niemann-Pick Type C2 (NPC2) in cnidarians are implicated in the transfer of sterol from symbionts. Here, we show that symbionts transfer bulk sterols to the host, host sterol utilization is plastic, and pharmacological inhibition of sterol trafficking disrupts symbiosis. Having undergone an anthozoan-specific expansion, “non-canonical” NPC2s respond to symbiosis and accumulate over time at the lysosomal-like organelle in which the symbiont resides (“symbiosome”). We demonstrate that both a non- and canonical Aiptasia NPC2 bind symbiont-produced sterols, yet only the non-canonical homologue exhibits increased stability at low pH. We propose that symbiotic cnidarians adapted pre-existing cholesterol-trafficking machinery to function in the highly acidic symbiosome environment, allowing corals to dominate nutrient-poor shallow tropical seas worldwide.

scholarly journals Sterol transfer by atypical cholesterol-binding NPC2 proteins in coral-algal symbiosis

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Elizabeth Ann Hambleton ◽  
Victor Arnold Shivas Jones ◽  
Ira Maegele ◽  
David Kvaskoff ◽  
Timo Sachsenheimer ◽  
...  
Keyword(s):  
Low Ph ◽  
Algal Symbiosis ◽  
Cell Components ◽  
Niemann Pick ◽  
Cholesterol Binding

Reef-building corals depend on intracellular dinoflagellate symbionts that provide nutrients. Besides sugars, the transfer of sterols is essential for corals and other sterol-auxotrophic cnidarians. Sterols are important cell components, and variants of the conserved Niemann-Pick Type C2 (NPC2) sterol transporter are vastly up-regulated in symbiotic cnidarians. Types and proportions of transferred sterols and the mechanism of their transfer, however, remain unknown. Using different pairings of symbiont strains with lines of Aiptasia anemones or Acropora corals, we observe both symbiont- and host-driven patterns of sterol transfer, revealing plasticity of sterol use and functional substitution. We propose that sterol transfer is mediated by the symbiosis-specific, non-canonical NPC2 proteins, which gradually accumulate in the symbiosome. Our data suggest that non-canonical NPCs are adapted to the symbiosome environment, including low pH, and play an important role in allowing corals to dominate nutrient-poor shallow tropical seas worldwide.

Wnt5a Promotes Lysosomal Cholesterol Egress and Protects Against Atherosclerosis

2021 ◽  
Author(s):  
Sara Awan ◽  
Magalie Lambert ◽  
Ali Imtiaz ◽  
Fabien Alpy ◽  
Catherine Tomasetto ◽  
...  
Keyword(s):  
Dietary Cholesterol ◽  
Cell Types ◽  
Cholesterol Content ◽  
Cholesterol Homeostasis ◽  
Cholesterol Trafficking ◽  
Atherosclerotic Lesions ◽  
Crucial Component ◽  
Multiple Cell ◽  
Niemann Pick

Background: Impairment of cellular cholesterol trafficking is at the heart of atherosclerotic lesions formation. This involves egress of cholesterol from the lysosomes and two lysosomal proteins, the Niemann-Pick C1 (NPC1) and NPC2 that promotes cholesterol trafficking. However, movement of cholesterol out the lysosome and how disrupted cholesterol trafficking leads to atherosclerosis is unclear. As the Wnt ligand, Wnt5a inhibits the intracellular accumulation of cholesterol in multiple cell types, we tested whether Wnt5a interacts with the lysosomal cholesterol export machinery and studied its role in atherosclerotic lesions formation. Methods: We generated mice deleted for the Wnt5a gene in vascular smooth muscle cells (VSMCs). To establish whether Wnt5a also protects against cholesterol accumulation in human VSMCs, we used a CRISPR/Cas9 guided nuclease approach to generate human VSMCs knockout for Wnt5a. Results: We show that Wnt5a is a crucial component of the lysosomal cholesterol export machinery. By increasing lysosomal acid lipase expression, decreasing metabolic signaling by the mTORC1 kinase, and through binding to NPC1 and NPC2, Wnt5a senses changes in dietary cholesterol supply and promotes lysosomal cholesterol egress to the endoplasmic reticulum (ER). Consequently, loss of Wnt5a decoupled mTORC1 from variations in lysosomal sterol levels, disrupted lysosomal function, decreased cholesterol content in the ER, and promoted atherosclerosis. Conclusions: These results reveal an unexpected function of the Wnt5a pathway as essential for maintaining cholesterol homeostasis in vivo.

scholarly journals Alternative Luciferase for Monitoring Bacterial Cells under Adverse Conditions

2005 ◽  
Vol 71 (7) ◽  
pp. 3427-3432 ◽  
Author(s):  
Siouxsie Wiles ◽  
Kathryn Ferguson ◽  
Martha Stefanidou ◽  
Douglas B. Young ◽  
Brian D. Robertson
Keyword(s):  
Deep Sea ◽  
Mycobacterium Smegmatis ◽  
Shuttle Vector ◽  
Low Ph ◽  
Bacterial Cells ◽  
Bacterial Luciferase ◽  
Adverse Conditions ◽  
Marine Copepod ◽  
Luciferase Enzyme ◽  
Enhanced Stability

ABSTRACT The availability of cloned luciferase genes from fireflies (luc) and from bacteria (luxAB) has led to the widespread use of bioluminescence as a reporter to measure cell viability and gene expression. The most commonly occurring bioluminescence system in nature is the deep-sea imidazolopyrazine bioluminescence system. Coelenterazine is an imidazolopyrazine derivative which, when oxidized by an appropriate luciferase enzyme, produces carbon dioxide, coelenteramide, and light. The luciferase from the marine copepod Gaussia princeps (Gluc) has recently been cloned. We expressed the Gluc gene in Mycobacterium smegmatis using a shuttle vector and compared its performance with that of an existing luxAB reporter. In contrast to luxAB, the Gluc luciferase retained its luminescence output in the stationary phase of growth and exhibited enhanced stability during exposure to low pH, hydrogen peroxide, and high temperature. The work presented here demonstrated the utility of the copepod luciferase bioluminescent reporter as an alternative to bacterial luciferase, particularly for monitoring responses to environmental stress stimuli.

scholarly journals Nogo-B Receptor Stabilizes Niemann-Pick Type C2 Protein and Regulates Intracellular Cholesterol Trafficking

2009 ◽  
Vol 10 (3) ◽  
pp. 208-218 ◽  
Author(s):  
Kenneth D. Harrison ◽  
Robert Qing Miao ◽  
Carlos Fernandez-Hernándo ◽  
Yajaira Suárez ◽  
Alberto Dávalos ◽  
...  
Keyword(s):  
Cholesterol Trafficking ◽  
Intracellular Cholesterol ◽  
Niemann Pick

scholarly journals Niemann-Pick Type C Disease and Intracellular Cholesterol Trafficking

2005 ◽  
Vol 280 (22) ◽  
pp. 20917-20920 ◽  
Author(s):  
Ta-Yuan Chang ◽  
Patrick C. Reid ◽  
Shigeki Sugii ◽  
Nobutaka Ohgami ◽  
Jonathan C. Cruz ◽  
...  
Keyword(s):  
Cholesterol Trafficking ◽  
Type C ◽  
Intracellular Cholesterol ◽  
Niemann Pick

scholarly journals A role for oxysterol-binding protein–related protein 5 in endosomal cholesterol trafficking

2011 ◽  
Vol 192 (1) ◽  
pp. 121-135 ◽  
Author(s):  
Ximing Du ◽  
Jaspal Kumar ◽  
Charles Ferguson ◽  
Timothy A. Schulz ◽  
Yan Shan Ong ◽  
...  
Keyword(s):  
Binding Protein ◽  
Lipid Binding ◽  
Cholesterol Trafficking ◽  
Cholesterol Accumulation ◽  
Oxysterol Binding Protein ◽  
Late Endosomes ◽  
Evolutionarily Conserved ◽  
Niemann Pick ◽  
Related Proteins ◽  
Lipid Binding Proteins

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.

scholarly journals Reduction of TMEM97 increases NPC1 protein levels and restores cholesterol trafficking in Niemann-pick type C1 disease cells

2016 ◽  
Vol 25 (16) ◽  
pp. 3588-3599 ◽  
Author(s):  
Darius Ebrahimi-Fakhari ◽  
Lara Wahlster ◽  
Fabian Bartz ◽  
Jennifer Werenbeck-Ueding ◽  
Maria Praggastis ◽  
...  
Keyword(s):  
Cholesterol Trafficking ◽  
Protein Levels ◽  
Niemann Pick

scholarly journals Defective cholesterol trafficking in Niemann-Pick C-deficient cells

FEBS Letters ◽  
2010 ◽  
Vol 584 (13) ◽  
pp. 2731-2739 ◽  
Author(s):  
Kyle B. Peake ◽  
Jean E. Vance
Keyword(s):  
Cholesterol Trafficking ◽  
Niemann Pick

scholarly journals In Vitro and In Vivo Evaluation of 6-O-α-Maltosyl-β-Cyclodextrin as a Potential Therapeutic Agent Against Niemann-Pick Disease Type C

2019 ◽  
Vol 20 (5) ◽  
pp. 1152 ◽  
Author(s):  
Nushrat Yasmin ◽  
Yoichi Ishitsuka ◽  
Madoka Fukaura ◽  
Yusei Yamada ◽  
Shuichi Nakahara ◽  
...  
Keyword(s):  
Free Cholesterol ◽  
Disease Type ◽  
Cholesterol Trafficking ◽  
Niemann Pick Disease ◽  
Type C ◽  
Niemann Pick ◽  
Deficient Mice ◽  
Pick Disease

Niemann-Pick disease Type C (NPC) is a rare lysosomal storage disease characterized by the dysfunction of intracellular cholesterol trafficking with progressive neurodegeneration and hepatomegaly. We evaluated the potential of 6-O-α-maltosyl-β-cyclodextrin (G2-β-CD) as a drug candidate against NPC. The physicochemical properties of G2-β-CD as an injectable agent were assessed, and molecular interactions between G2-β-CD and free cholesterol were studied by solubility analysis and two-dimensional proton nuclear magnetic resonance spectroscopy. The efficacy of G2-β-CD against NPC was evaluated using Npc1 deficient Chinese hamster ovary (CHO) cells and Npc1 deficient mice. G2-β-CD in aqueous solution showed relatively low viscosity and surface activity; characteristics suitable for developing injectable formulations. G2-β-CD formed higher-order inclusion complexes with free cholesterol. G2-β-CD attenuated dysfunction of intercellular cholesterol trafficking and lysosome volume in Npc1 deficient CHO cells in a concentration dependent manner. Weekly subcutaneous injections of G2-β-CD (2.9 mmol/kg) ameliorated abnormal cholesterol metabolism, hepatocytomegaly, and elevated serum transaminases in Npc1 deficient mice. In addition, a single cerebroventricular injection of G2-β-CD (21.4 μmol/kg) prevented Purkinje cell loss in the cerebellum, body weight loss, and motor dysfunction in Npc1 deficient mice. In summary, G2-β-CD possesses characteristics favorable for injectable formulations and has therapeutic potential against in vitro and in vivo NPC models.

scholarly journals Targeting defective sphingosine kinase 1 in Niemann–Pick type C disease with an activator mitigates cholesterol accumulation

2020 ◽  
Vol 295 (27) ◽  
pp. 9121-9133 ◽  
Author(s):  
Jason Newton ◽  
Elisa N. D. Palladino ◽  
Cynthia Weigel ◽  
Michael Maceyka ◽  
Markus H. Gräler ◽  
...  
Keyword(s):  
Specific Inhibitor ◽  
Sphingosine Kinase ◽  
Autophagic Flux ◽  
Sphingosine Kinase 1 ◽  
Cholesterol Trafficking ◽  
Cholesterol Accumulation ◽  
Cellular Models ◽  
Ester Formation ◽  
Type C ◽  
Niemann Pick

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.

Sign in / Sign up

Export Citation Format

Share Document