Human Hepatocyte Nuclear Factors (HNF1 and LXRb) Regulates CYP7A1 in HIV-Infected Black South African Women with Gallstone Disease: A Preliminary Study

Background: Female sex, high estrogen levels, aging, obesity and dyslipidemia are some of the risk factors associated with gallstone formation. HIV infected patients on combination antiretroviral therapy (cART) are more prone to hypercholesterolemia. Bile acid synthesis is initiated by cholesterol 7-alpha hydroxylase (CYP7A1) and regulated by hepatocyte nuclear factors (HNF1α, HNF4α and LXRb).Aim/ Objective: To evaluate the expression of HNF1α, HNF4α, LXRb and miRNAs (HNF4α specific: miR-194-5p and miR-122*_1) that regulate CYP7A1 transcription in HIV-infected Black South African women on cART and presenting with gallstones relative to HIV negative patients with gallstone disease. Methods: Females (n = 96) presenting with gallstone disease were stratified based on HIV status. The gene expression of CYP7A1, HNF1α, HNF4α, LXRb, miR-194-5p and miR-122*_1 was determined using RT-qPCR. Messenger RNA and miRNA levels were reported as fold change expressed as 2-ΔΔCt (RQ min; RQ max). Fold changes >2 and <0.5 were considered significant. Results: HIV-infected females were older in age (p = 0.0267) and displayed higher low-density lipoprotein cholesterol (LDL-c) (p = 0.0419), CYP7A1 [2.078-fold (RQ min: 1.278; RQ max: 3.381)], LXRb [2.595-fold (RQ min: 2.001; RQ max: 3.000)] and HNF1α [3.428 (RQ min: 1.806; RQ max: 6.507] levels. HNF4α [0.642-fold (RQ min: 0.266; RQ max: 1.55)], miR-194-5p [0.527-fold (RQ min: 0.37; RQ max: 0.752)] and miR-122*_1 [0.595-fold (RQ min: 0.332; RQ max: 1.066)] levels were lower in HIV-infected females. Conclusions: HIV-infected women with gallstone disease displayed higher LDL-c levels and increased bile acid synthesis which was evident by the elevated expression of CYP7A1, HNF1α and LXRb. This could have been further influenced by cART and aging.

Mutations in transcription factor as rare causes of diabetes in pregnancy

MODY1 and MODY3 represent rare causes of diabetes in pregnancy. Establishing a molecular diagnosis of MODY1 or MODY3 during pregnancy may be important for minimizing risk of perinatal complications and for improving glycemic control after pregnancy. The objective of the study was to evaluate the contribution of mutations in HNF4A and HNF1A genes in development of diabetes in pregnancy and to describe clinical characteristics of diabetes in pregnancy associated with these mutations. 230 pregnant women (20-43 years) with different type of glucose intolerance complicated during their current pregnancy were included in the study. A custom NGS panel targeting 28 diabetes causative genes was used for sequencing. Heterozygous mutations in HNF4A and HNF1A genes were detected in 3% of cases. Mutations p.I271T in HNF4A gene and p.L148F, p.Y265C, p.G288W in HNF1A gene were novel. This study includes a description of patients with pregnancy diabetes due to mutations in hepatocyte nuclear factors.

Multiple Functions of Cellular FLIP Are Essential for Replication of Hepatitis B Virus

ABSTRACTHepatitis B virus (HBV) infection is a leading cause of liver diseases; however, the host factors which facilitate the replication and persistence of HBV are largely unidentified. Cellular FLICE inhibitory protein (c-FLIP) is a typical antiapoptotic protein. In many cases of liver diseases, the expression level of c-FLIP is altered, which affects the fate of hepatocytes. We previously found that c-FLIP and its cleaved form interact with HBV X protein (HBx), which is essential for HBV replication, and regulate diverse cellular signals. In this study, we investigated the role of endogenous c-FLIP in HBV replication and its underlying mechanisms. The knockdown of endogenous c-FLIP revealed that this protein regulates HBV replication through two different mechanisms. (i) c-FLIP interacts with HBx and protects it from ubiquitin-dependent degradation. The N-terminal DED1 domain of c-FLIP is required for HBx stabilization. (ii) c-FLIP regulates the expression or stability of hepatocyte nuclear factors (HNFs), which have critical roles in HBV transcription and maintenance of hepatocytes. c-FLIP regulates the stability of HNFs through physical interactions. We verified our findings in three HBV infection systems: HepG2-NTCP cells, differentiated HepaRG cells, and primary human hepatocytes. In conclusion, our results identify c-FLIP as an essential factor in HBV replication. c-FLIP regulates viral replication through its multiple effects on viral and host proteins that have critical roles in HBV replication.IMPORTANCEAlthough the chronic hepatitis B virus (HBV) infection still poses a major health concern, the host factors which are required for the replication of HBV are largely uncharacterized. Our studies identify cellular FLICE inhibitory protein (c-FLIP) as an essential factor in HBV replication. We found the dual roles of c-FLIP in regulation of HBV replication: c-FLIP interacts with HBx and enhances its stability and regulates the expression or stability of hepatocyte nuclear factors which are essential for transcription of HBV genome. Our findings may provide a new target for intervention in persistent HBV infection.