MicroRNA-122 associates with serum apolipoprotein B but not liver fibrosis markers in CHC genotype 1 infection.

miR-122 is the predominant liver miRNA that regulates hepatic lipid metabolism and inflammation. Hepatitis C virus (HCV) modulates host intracellular lipid metabolism. HCV stability and propagation also depend on an interaction between virus and miR-122. Our aims were to examine the associations between miR-122, apolipoproteins, and serum makers of fibrosis in chronic hepatitis C (CHC) patients. We evaluated baseline sera from 36 CHC genotype 1 patients who completed the Phase IIa study of miravirsen (LNA oligonucleotide targeting miR-122). Samples were assessed for liver transaminases, IL 28B genotype, IP-10, and lipid profiles. The noninvasive markers of liver fibrosis, APRI, and FIB-4, were calculated using standard formulae. miR-122 levels were measured using RT-PCR and expressed as fold-change compared to normal healthy controls. CHC patients were mostly male (61%) with mean age 47.5 ± 11.6 years. Patients with higher ApoB (ApoB/ULN ≥ 0.5) has significantly lower miR-122 levels in compared to patients with lower ApoB (ApoB/ULN < 0.5). (8.28 ± 6.23 vs. 16.28 ± 13.71; P = 0.02). There were no similar associations between miR-122 and ApoA-1 or between HCV RNA and lipoproteins. There were no differences in miR-122 levels between patients with different stages of fibrosis determined by APRI or FIB-4. Patients with lower ApoB had higher serum miR-122 levels. However, we cannot identify significant association between miR-122, ApoA-1, or fibrosis markers in this small cohort of CHC genotype 1 patients. The mechanism of HCV dyslipidemia is complex and could partly relate to the effect of miR-122 on lipid metabolism which requires further evaluation in a larger study.

Increased HDL cholesterol and apoA-I in humans and mice treated with a novel SR-BI inhibitor.

OBJECTIVE: Increasing HDL levels is a potential strategy for the treatment of atherosclerosis. METHODS AND RESULTS: ITX5061, a molecule initially characterized as a p38 MAPK inhibitor, increased HDL-C levels by 20% in a human population of hypertriglyceridemic subjects with low HDL levels. ITX5061 also moderately increased apoA-I but did not affect VLDL/LDL cholesterol or plasma triglyceride concentrations. ITX5061 increased HDL-C in WT and human apoA-I transgenic mice, and kinetic experiments showed that ITX5061 decreased the fractional catabolic rate of HDL-CE and reduced its hepatic uptake. In transfected cells, ITX5061 inhibited SR-BI-dependent uptake of HDL-CE. Moreover, ITX5061 failed to increase HDL-C levels in SR-BI(-/-) mice. To assess effects on atherosclerosis, ITX5061 was given to atherogenic diet-fed Ldlr(+/-) mice with or without CETP expression for 18 weeks. In both the control and CETP-expressing groups, ITX5061-treated mice displayed reductions of early atherosclerotic lesions in the aortic arch -40%, P<0.05), and a nonsignificant trend to reduced lesion area in the proximal aorta. CONCLUSIONS: Our data indicate that ITX5061 increases HDL-C levels by inhibition of SR-BI activity. This suggests that pharmacological inhibition of SR-BI has the potential to raise HDL-C and apoA-I levels without adverse effects on VLDL/LDL cholesterol levels in humans.