Lysophosphatidylcholine acyltransferase 1 is downregulated by hepatitis C virus: impact on production of lipo-viro-particles

Beilstein, Frauke; Lemasson, Matthieu; Pène, Véronique; Rainteau, Dominique; Demignot, Sylvie; Rosenberg, Arielle R.

doi:10.1136/gutjnl-2016-311508

Cited by 19 publications

(18 citation statements)

References 62 publications

(69 reference statements)

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“…Amounts of albumin secreted into the medium were determined by the human albumin ELISA Quantitation Kit (Bethyl; http://www.bethyl.com) following manufacturer’s instructions. Levels of APOB100 secreted into the medium were quantified by using the total human ApoB ELISA assay from ALerCHEK, as previously described [24].…”

Section: Methodsmentioning

confidence: 99%

“…All analyses were performed at day 3 post-inoculation except for the assessment of HCV genome replication, which was done at day 1 post-inoculation, i.e., under conditions of a single infection cycle. Indeed, at later time points, multiple rounds of infection are expected to cause a bias in the assessment of viral genome replication per se if the production of viral particles is affected [24].…”

Section: Methodsmentioning

confidence: 99%

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Low-density lipoprotein receptor-deficient hepatocytes differentiated from induced pluripotent stem cells allow familial hypercholesterolemia modeling, CRISPR/Cas-mediated genetic correction, and productive hepatitis C virus infection

et al. 2019

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Background Familial hypercholesterolemia type IIA (FH) is due to mutations in the low-density lipoprotein receptor (LDLR) resulting in elevated levels of low-density lipoprotein cholesterol (LDL-c) in plasma and in premature cardiovascular diseases. As hepatocytes are the only cells capable of metabolizing cholesterol, they are therefore the target cells for cell/gene therapy approaches in the treatment of lipid metabolism disorders. Furthermore, the LDLR has been reported to be involved in hepatitis C virus (HCV) entry into hepatocytes; however, its role in the virus infection cycle is still disputed. Methods We generated induced pluripotent stem cells (iPSCs) from a homozygous LDLR-null FH-patient (FH-iPSCs). We constructed a correction cassette bearing LDLR cDNA under the control of human hepatic apolipoprotein A2 promoter that targets the adeno-associated virus integration site AAVS1 . We differentiated both FH-iPSCs and corrected FH-iPSCs (corr-FH-iPSCs) into hepatocytes to study statin-mediated regulation of genes involved in cholesterol metabolism. Upon HCV particle inoculation, viral replication and production were quantified in these cells. Results We showed that FH-iPSCs displayed the disease phenotype. Using homologous recombination mediated by the CRISPR/Cas9 system, FH-iPSCs were genetically corrected by the targeted integration of a correction cassette at the AAVS1 locus. Both FH-iPSCs and corr-FH-iPSCs were then differentiated into functional polarized hepatocytes using a stepwise differentiation approach (FH-iHeps and corr-FH-iHeps). The correct insertion and expression of the correction cassette resulted in restoration of LDLR expression and function (LDL-c uptake) in corr-FH-iHeps. We next demonstrated that pravastatin treatment increased the expression of genes involved in cholesterol metabolism in both cell models. Moreover, LDLR expression and function were also enhanced in corr-FH-iHeps after pravastatin treatment. Finally, we demonstrated that both FH-iHeps and corr-FH-iHeps were as permissive to viral infection as primary human hepatocytes but that virus production in FH-iHeps was significantly decreased compared to corr-FH-iHeps, suggesting a role of the LDLR in HCV morphogenesis. Conclusions Our work provides the first LDLR-null FH cell model and its corrected counterpart to study the regulation of cholesterol metabolism and host determinants of HCV life cycle, and a platform to screen drugs for treating dyslipidemia and HCV infection. Electronic supplementary material The online version of this article (10.1186/s13287-019-1342-6) contains supplementary material, which is available to authorized users.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Low-density lipoprotein receptor-deficient hepatocytes differentiated from induced pluripotent stem cells allow familial hypercholesterolemia modeling, CRISPR/Cas-mediated genetic correction, and productive hepatitis C virus infection

et al. 2019

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“…Given the important roles of phospholipids in LDs and VLDL metabolism, it is conceivable that phospholipids may have roles in HCV infection. In a recent study, Beilstein et al (134) demonstrated that HCV infection in primary human hepatocytes and Huh7.5.1 cells inhibits gene expression of LPCAT1. LPCAT1 depletion increases the production of HCV particles with high infectivity, likely through remodeling LD metabolism and modulating VLDL secretion.…”

Section: Lpcat1 In Hepatitis C Virus Infectionmentioning

confidence: 99%

Phospholipid Remodeling in Physiology and Disease

Wang

Tontonoz

2019

Annu. Rev. Physiol.

305

240

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Phospholipids are major constituents of biological membranes. The fatty acyl chain composition of phospholipids determines the biophysical properties of membranes and thereby affects their impact on biological processes. The composition of fatty acyl chains is also actively regulated through a deacylation and reacylation pathway called Lands’ cycle. Recent studies of mouse genetic models have demonstrated that lysophosphatidylcholine acyltransferases (LPCATs), which catalyze the incorporation of fatty acyl chains into the sn-2 site of phosphatidylcholine, play important roles in pathophysiology. Two LPCAT family members, LPCAT1 and LPCAT3, have been particularly well studied. LPCAT1 is crucial for proper lung function due to its role in pulmonary surfactant biosynthesis. LPCAT3 maintains systemic lipid homeostasis by regulating lipid absorption in intestine, lipoprotein secretion, and de novo lipogenesis in liver. Mounting evidence also suggests that changes in LPCAT activity may be potentially involved in pathological conditions, including nonalcoholic fatty liver disease, atherosclerosis, viral infections, and cancer. Pharmacological manipulation of LPCAT activity and membrane phospholipid composition may provide new therapeutic options for these conditions.

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“…Recent studies favor the role of lipid mobilization from lipid droplets in the morphogenesis and secretion of HCV LVPs. The knockdown of the lipid droplet phospholipid-remodeling enzyme lysophosphatidylcholine acyltransferase 1 (LPCAT1) increases the cellular triacylglycerol content and HCV LVP secretion (24). Similarly, ␣/␤-hydrolase domain-containing 5 (ABHD5), a lipid droplet-associated lipase, is required for the assembly and release of HCV LVPs (25).…”

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confidence: 99%

Hepatitis C Virus Lipoviroparticles Assemble in the Endoplasmic Reticulum (ER) and Bud off from the ER to the Golgi Compartment in COPII Vesicles

Syed

Khan

Yang

et al. 2017

J Virol

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Hepatitis C virus (HCV) exists as a lipoprotein-virus hybrid lipoviroparticle (LVP).In vitro studies have demonstrated the importance of apolipoproteins in HCV secretion and infectivity, leading to the notion that HCV coopts the secretion of very-low-density lipoprotein (VLDL) for its egress. However, the mechanisms involved in virus particle assembly and egress are still elusive. The biogenesis of VLDL particles occurs in the endoplasmic reticulum (ER), followed by subsequent lipidation in the ER and Golgi compartment. The secretion of mature VLDL particles occurs through the Golgi secretory pathway. HCV virions are believed to latch onto or fuse with the nascent VLDL particle in either the ER or the Golgi compartment, resulting in the generation of LVPs. In our attempt to unravel the collaboration between HCV and VLDL secretion, we studied HCV particles budding from the ER en route to the Golgi compartment in COPII vesicles. Biophysical characterization of COPII vesicles fractionated on an iodixanol gradient revealed that HCV RNA is enriched in the highly buoyant COPII vesicle fractions and cofractionates with apolipoprotein B (ApoB), ApoE, and the HCV core and envelope proteins. Electron microscopy of immunogoldlabeled microsections revealed that the HCV envelope and core proteins colocalize with apolipoproteins and HCV RNA in Sec31-coated COPII vesicles. Ultrastructural analysis also revealed the presence of HCV structural proteins, RNA, and apolipoproteins in the Golgi stacks. These findings support the hypothesis that HCV LVPs assemble in the ER and are transported to the Golgi compartment in COPII vesicles to embark on the Golgi secretory route.IMPORTANCE HCV assembly and release accompany the formation of LVPs that circulate in the sera of HCV patients and are also produced in an in vitro culture system. The pathway of HCV morphogenesis and secretion has not been fully understood. This study investigates the exact site where the association of HCV virions with host lipoproteins occurs. Using immunoprecipitation of COPII vesicles and immunogold electron microscopy (EM), we characterize the existence of LVPs that cofractionate with lipoproteins, viral proteins, RNA, and vesicular components. Our results show that this assembly occurs in the ER, and LVPs thus formed are carried through the Golgi network by vesicular transport. This work provides a unique insight into the HCV LVP assembly process within infected cells and offers opportunities for designing antiviral therapeutic cellular targets.

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Lysophosphatidylcholine acyltransferase 1 is downregulated by hepatitis C virus: impact on production of lipo-viro-particles

Cited by 19 publications

References 62 publications

Low-density lipoprotein receptor-deficient hepatocytes differentiated from induced pluripotent stem cells allow familial hypercholesterolemia modeling, CRISPR/Cas-mediated genetic correction, and productive hepatitis C virus infection

Low-density lipoprotein receptor-deficient hepatocytes differentiated from induced pluripotent stem cells allow familial hypercholesterolemia modeling, CRISPR/Cas-mediated genetic correction, and productive hepatitis C virus infection

Phospholipid Remodeling in Physiology and Disease

Hepatitis C Virus Lipoviroparticles Assemble in the Endoplasmic Reticulum (ER) and Bud off from the ER to the Golgi Compartment in COPII Vesicles

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