Polimorfismos de los genes LEP, LDLR, APOA4, sus relaciones con sobrepeso, obesidad y riesgo de enfermedades crónicas en adultos del estado Sucre, Venezuela

LDLR and PCSK9 3´UTR variants and their putative effects on microRNA molecular interactions in familial hypercholesterolemia: a computational approach

BACKGROUND

Familial hypercholesterolemia (FH) is caused by pathogenic variants in low-density lipoprotein (LDL) receptor (LDLR) or its associated genes, including apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and LDLR adaptor protein 1 (LDLRAP1). However, approximately 40% of the FH patients clinically diagnosed (based on FH phenotypes) may not carry a causal variant in a FH-related gene. Variants located at 3' untranslated region (UTR) of FH-related genes could elucidate mechanisms involved in FH pathogenesis. This study used a computational approach to assess the effects of 3'UTR variants in FH-related genes on miRNAs molecular interactions and to explore the association of these variants with molecular diagnosis of FH.

METHODS AND RESULTS

Exons and regulatory regions of FH-related genes were sequenced in 83 FH patients using an exon-target gene sequencing strategy. In silico prediction tools were used to study the effects of 3´UTR variants on interactions between miRNAs and target mRNAs. Pathogenic variants in FH-related genes (molecular diagnosis) were detected in 44.6% FH patients. Among 59 3'UTR variants identified, LDLR rs5742911 and PCSK9 rs17111557 were associated with molecular diagnosis of FH, whereas LDLR rs7258146 and rs7254521 and LDLRAP1 rs397860393 had an opposite effect (p < 0.05). 3´UTR variants in LDLR (rs5742911, rs7258146, rs7254521) and PCSK9 (rs17111557) disrupt interactions with several miRNAs, and more stable bindings were found with LDLR (miR-4435, miR-509-3 and miR-502) and PCSK9 (miR-4796).

CONCLUSION

LDLR and PCSK9 3´UTR variants disturb miRNA:mRNA interactions that could affect gene expression and are potentially associated with molecular diagnosis of FH.

Naringin Activates AMPK Resulting in Altered Expression of SREBPs, PCSK9, and LDLR To Reduce Body Weight in Obese C57BL/6J Mice

Previous investigations have shown molecular cross-talk among activated adenosine monophosphate-activated protein kinase (AMPK), proprotein convertase subtilisin/kexin type 9 (PCSK9), sterol regulatory element-binding proteins (SREBPs), and low-density lipoprotein receptor (LDLR) and that it may be an innovative pharmacologic objective for treating obesity. We scrutinized the beneficial effect of naringin, a flavanone-7- O-glycoside, on obesity and the mechanisms in the present study. We arbitrarily divided 50 mice into five groups ( n = 10): 25 or 50 or 100 mg/kg/day naringin-treated obese mice (gavage for 8 weeks), untreated obese mice, and C57BL/6J control. After 8 weeks, body weight was 51.8 ± 4.4 in the untreated obese mice group, while the weights were 41.4 ± 4.1, 34.6 ± 2.2, and 28.0 ± 2.3 in 25, 50,100 mg/kg naringin groups, respectively. Moreover, naringin treatment significantly decreased plasma 8-isoprostane (an indicator of the oxidative stress) level, fat weight, liver weight, hepatic total cholesterol concentration, hepatic triglyceride concentration, plasma leptin level, plasma insulin content, plasma low-density lipoprotein cholesterol level, and plasma PCSK9 production concomitantly with down-regulated expression of SREBP-2, PCSK9, and SREBP-1, and up-regulated expression of p-AMPKα and LDLR. The present results suggest that naringin activates AMPK resulting in altered expression of SREBPs, PCSK9, and LDLR to reduce the body weight of obese C57BL/6J mice.