Oxidized Low-Density Lipoprotein Is a Novel Predictor of Interferon Responsiveness in Chronic Hepatitis C Infection

Immunometabolic Effect of Cholesterol in Hepatitis C Infection: Implications in Clinical Management and Antiviral Therapy

Hepatitis C virus (HCV) is a lipid-enveloped virion particle that causes infection to the liver, and as part of its life cycle, it disrupts the host lipid metabolic machinery, particularly the cholesterol synthesis pathway. The innate immune response generated by liver resident immune cells is responsible for successful viral eradication. Unfortunately, most patients fail to eliminate HCV and progress to chronic infection. Chronic infection is associated with hepatic fat accumulation and inflammation that triggers fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Despite that the current direct-acting antiviral agents have increased the cure rate of HCV infection, viral genotype and the host genetic background influence both the immune response and lipid metabolism. In this context, recent evidence has shown that cholesterol and its derivatives such as oxysterols might modulate and potentialize the hepatic innate immune response generated against HCV. The impairment of the HCV life cycle modulated by serum cholesterol could be relevant for the clinical management of HCV-infected patients before and after treatment. Alongside, cholesterol levels are modulated either by genetic variations in IL28B, ApoE, and LDLR or by dietary components. Indeed, some nutrients such as unsaturated fatty acids have demonstrated to be effective against HCV replication. Thus, cholesterol modifications may be considered as a new adjuvant strategy for HCV infection therapy by providing a biochemical tool that guides treatment decisions, an improved treatment response and favoring viral clearance. Herein, the mechanisms by which cholesterol contributes to the immune response against HCV infection and how genetic and environmental factors may affect this role are reviewed.

Identification of potential anti-hepatitis C virus agents targeting non structural protein 5B using computational techniques

Hepatitis C virus (HCV) nonstructural protein 5B (NS5B) is an RNA-dependent RNA polymerase that plays a key role in HCV replication, and, hence, NS5B is an attractive target for hepatitis C drug discovery. Hepatitis C is a chronic liver disease affecting the global population significantly. Many NS5B inhibitors targeting active site were launched in recent years, however, still there exists a pressing need for cost-effective therapies with pan genotypic activity and therapies targeting niche HCV population with comorbities and resistant to earlier therapies. The objective of the current study is to identify potential anti-HCV agents from FDA approved drugs that are already in the market for a different disease-Drug repurposing approach. A combination of computational chemistry and computational biology techniques was used to discover potential therapies for hepatitis C targeting the NS5B Thumb I allosteric site. Computational chemistry analysis emphasized the fact that fluvastatin, a lipid lowering agent, and olopatadine, an antihistamine, exhibited good binding affinity to NS5B. In addition, gene set enrichment analysis brought to light the significant overlap between disease characteristic features and the mechanism of action of fluvastatin and olopatadine. The current study concludes the potentially beneficial use of fluvastatin in niche hepatitis C patient population suffering from nonalcoholic fatty liver diseases.

Role of SR-BI in atherosclerosis, malignancies, and infectious diseases

Scavenger receptor class B type I (SR-BI) is a high-affinity receptor for high-density lipoprotein (HDL). The primary role of this receptor is the selective uptake of HDLs in the liver through reverse cholesterol transport. SR-BI interacts with HDL to regulate lipid metabolism and affects various vascular cell functions involved in atherosclerosis (As). In addition, SR-BI is involved in the development of malignant tumors and infectious diseases. This article reviews the function and potential therapeutic targets of SR-BI in As, malignancies, and infectious diseases.

Scavenger receptor class B member 1 (SCARB1) variants modulate hepatitis C virus replication cycle and viral load

BACKGROUND & AIMS

There are numerous coding and non-coding variants in the SCARB1 gene that encodes scavenger receptor class B member 1 (SR-BI), a key receptor for both high density lipoproteins and hepatitis C virus (HCV). Many have been linked to clinical phenotypes, yet their impact on the HCV replication cycle is incompletely understood. The aim of this study was to analyze the impact of these variants on the molecular biology and clinical course of HCV.

METHODS

We analyzed key coding non-synonymous as well as non-coding SCARB1 variants using virological in vitro and human genetics approaches.

RESULTS

Non-synonymous variants: S112F and T175A have greatly reduced HCV receptor function. When present on the cell surface, these variants are impaired in their ability to interact with HCV E2. Non-coding variants: The G allele in rs3782287 is associated with decreased viral load. Haplotype analysis confirmed these findings and identified haplotype rs3782287 A/rs5888 C as a risk allele associated with increased viral load. We also detected a trend towards lower hepatic SR-BI expression in individuals with the rs3782287 GG genotype associated with low viral load suggesting a potential underlying mechanism.

CONCLUSION

Coding and non-coding genetic SCARB1 variants modulate the HCV replication cycle and possibly clinical features of hepatitis C. These findings underscore the relevance of SR-BI as an HCV receptor and contribute to our understanding of inter-individual variation in HCV infection.

LAY SUMMARY

The cell surface receptor SR-BI (scavenger receptor class B member 1), is essential for hepatitis C virus (HCV) entry into hepatocytes. Variations in the gene coding this receptor influence infectivity and viral load. We analyzed these variations to gain a better understanding of inter-individual differences over the course of HCV infection.