circRNA_0046366 inhibits hepatocellular steatosis by normalization of PPAR signaling

AIM To investigate micro(mi)R-34 a-antagonizing circular(circ)RNA that underlies hepatocellular steatosis.METHODS The effect of circ RNA on mi R-34 a was recognized by the mi RNA response element(MRE), and validated by the dual-luciferase reporter assay. Its association with hepatocellular steatosis was investigated in Hep G2-based hepatocellular steatosis induced by free fatty acids(FFAs; 2:1 oleate:palmitate) stimulation. After normalization of the steatosis-related circRNA by expression vector, analysis of mi R-34 a activity,peroxisome proliferator-activated receptor(PPAR)α level, and expression of downstream genes were carried out so as to reveal its impact on the mi R-34 a/PPARα regulatory system. Both triglyceride(TG) assessment and cytopathological manifestations uncovered the role of circRNA in miR-34 a-dependent hepatosteatogenesis.RESULTS Bioinformatic and functional analysis verified circRNA_0046366 to antagonize the activity of mi R-34 a via MRE-based complementation. In contrast to its lowered level during FFA-induced hepatocellular steatosis, circ RNA_0046366 up-regulation abolished the mi R-34 a-dependent inhibition of PPARα that played a critical role in metabolic signaling pathways. PPARα restoration exerted transcriptional improvement to multiple genes responsible for lipid metabolism. TGspecific lipolytic genes [carnitine palmitoyltransferase 1 A(CPT1 A) and solute-carrier family 27 A(SLC27 A)] among these showed significant increase in their expression levels. The circ RNA_0046366-related rebalancing of lipid homeostasis led to dramatic reduction of TG content, and resulted in the ameliorated phenotype of hepatocellular steatosis.CONCLUSION Dysregulation of circ RNA_0046366/mi R-34 a/PPARα signaling may be a novel epigenetic mechanism underlying hepatocellular steatosis. circ RNA_0046366 serves as a potential target for the treatment of hepatic steatosis.

Prevalence,clinical characteristics,risk factors,and indicators for lean Chinese adults with nonalcoholic fatty liver disease

BACKGROUND Nonalcoholic fatty liver disease(NAFLD)is one of the most common chronic diseases in the world.Nowadays,the percentage of non-obese or lean patients with NAFLD is increasing.NAFLD in non-obese populations,especially the lean subgroup with a normal waist circumference(WC),might lead to more problems than obese individuals,as these individuals may not visit clinics for NAFLD diagnosis or ignore the diagnosis of NAFLD.If the precise characteristics of these populations,especially the lean subgroup,are identified,the clinicians would be able to provide more appropriate advice and treatment to these populations.AIM To investigate the prevalence,clinical characteristics,risk factors,and possible indicators for NAFLD in lean Chinese adults with a normal WC.METHODS People without diabetes mellitus or significant alcohol consumption who underwent routine health examinations were included.Their fatty liver index(FLI),abdominal ultrasonography results,and controlled attenuation parameter were all assessed.Genotyping for single-nucleotide polymorphisms associated with NAFLD was performed in another small group consisting of biopsy-proven NAFLD subjects and healthy controls.RESULTS A total of 2715 subjects who underwent routine health examinations were included in the study.Among 810 lean participants with a normal WC,142(17.5%)fulfilled the diagnostic criteria for NAFLD.Waist-height ratio,hemoglobin,platelets,and triglycerides were significant factors associated with the presence of NAFLD in these participants.The appropriate cut-off value of the FLI score in screening for NAFLD in the lean subjects with a normal WC was 25.15,which had a 77.8%sensitivity and 75.9%specificity.There was no significant difference in the single-nucleotide polymorphisms in the SIRT1,APOC3,PNPLA3,AGTR1,and PPARGC1A genes between lean subjects with and without NAFLD(P<0.05).CONCLUSION NAFLD is not uncommon in lean Chinese adults even with a normal WC.Metabolic factors,rather than genetic factors,may play important roles in the development of NAFLD in this population.A lower cut-off value of the FLI score in screening for NAFLD should be used for lean Chinese adults with a normal WC.

Linked PNPLA3 polymorphisms confer susceptibility to nonalcoholic steatohepatitis and decreased viral load in chronic hepatitis B

AIM:To investigate the association of PNPLA3 polymorphisms with concurrent chronic hepatitis B(CHB) and nonalcoholic fatty liver disease(NAFLD).METHODS:A cohort of Han patients with biopsyproven CHB,with or without NAFLD(CHB group,n = 51;CHB + NAFLD group,n = 57),and normal controls(normal group,n = 47) were recruited from Northern(Tianjin),Central(Shanghai),and Southern(Zhangzhou) China.Their PNPLA3 polymorphisms were genotyped by gene sequencing.The association between PNPLA3 polymorphisms and susceptibility to NAFLD,and clinical characteristics of NAFLD were evaluated on the basis of physical indices,liver function tests,glycolipid metabolism,and histopathologic scoring.The association of PNPLA3 polymorphisms and hepatitis B virus(HBV) load was determined by the serum level of HBV DNA.RESULTS:After adjusting for age,sex,and body mass index,we found that four linked single nucleotide polymorphisms(SNPs) of PNPLA3,including the rs738409 G allele(CHB + NAFLD group vs CHB group:odds ratio[OR]= 2.77,95%confidence interval[CI]:1.18-6.54;P = 0.02),rs3747206 T allele(CHB+ NAFLD group vs CHB group:OR = 2.77,95%CI:1.18-6.54;P = 0.02),rs4823173 A allele(CHB +NAFLD group vs CHB group:OR = 2.73,95%CI:1.16-6.44;P= 0.02),and rs2072906 G allele(CHB+ NAFLD group vs CHB group:OR = 3.05,95%CI:1.28-7.26;P = 0.01),conferred high risk to NAFLD in CHB patients.In patients with both CHB and NAFLD,these genotypes of PNPLA3 polymorphisms were associated with increased susceptibility to nonalcoholic steatohepatitis(NASH)(NAFLD activity score ≥3;P =0.01-0.03) and liver fibrosis(>1 Metavir grading;P =0.01-0.04).As compared to those with C/C and C/G at rs738409,C/C and C/T at rs3747206,G/G and G/A at rs4823173,and A/A and A/G at rs2072906,patients in the CHB + NAFLD group with G/G at rs738409,T/T at rs3747206,A/A at rs4823173,and G/G at rs2072906 showed significantly lower serum levels of HBV DNA(P< 0.01-0.05).CONCLUSION:Four linked SNPs of PNPLA3(rs738409,rs3747206,rs4823173,and rs2072906) are correlated with susceptibility to NAFLD,NASH,liver fibrosis,and HBV dynamics in CHB patients.

Noninvasive diagnosis of nonalcoholic steatohepatitis:Emerging approaches

Nonalcoholic steatohepatitis(NASH),a severe type of nonalcoholic fatty liver disease(NAFLD),progresses toward liver fibrosis/cirrhosis,liver failure,and furthermore,hepatocellular carcinoma(HCC)[1].The pathological manifestations are hepatocyte steatosis( >5%),lobular inflammation,and ballooning degeneration,with or without fibrogenesis[2].NAFLD/NASH results from sedentary life style,western diet,and obesity.We have witnessed the conversion of spectrum of chronic liver diseases from viral hepatitis as the leading cause to NAFLD/NASH worldwide[3].Diagnosis of NASH is therefore of great importance for the clinical management,evaluation,and follow-up.