Targeted inhibition of PPARα ameliorates CLA‐induced hypercholesterolemia via hepatic cholesterol biosynthesis reprogramming

Abstract

Background & Aims: Disruption of lipid metabolism is largely linked to metabolic disorders, such as hypercholesterolemia (HCL) and liver steatosis. While cholesterol metabolic re-programmers can serve as targets for relevant interventions. Here we explored the dietary conjugated linoleic acids (CLA)-induced HCL in mice and the molecular regulation behind it.Methods: A high dose of CLA supplementation in the diet was used to induce HCL in mice and was found to cause a hyper-activated cholesterol biosynthesis programme in the liver, leading to cholesterol metabolism dysregulation. The effects of a small-molecule drug targeting PPARα, i.e., GW6471 were studied in vivo in mice fed diets with CLA supplementation for 28 days, and in primary hepatocytes derived from HCL-mice in vitro. Results:We demonstrate that CLA induced HCL and liver steatosis through multiple pathways. Among which was the PPARα-mediated cholesterogenesis. It was found to cooperate with SREBP2 via binding to Hmgcr and Dhcr7 (genes encoding key enzymes of the cholesterol biosynthetic pathway) and recruits the histone marks H3K27ac and H3K4me1 and cofactors. PPARα inhibition disrupts its physical association with SREBP2 by blocking cobinding of PPARα and SREBP2 to the genomic DNA response element. We showed that NR RORγ functions as an essential mediator that facilitates the interaction of PPARα and SREBP2 to modulate the cholesterol biosynthesis genes expression. Conclusions:Our study unravels that the small-molecule compound GW6471 exerts an attractive therapeutic effect for CLA-induced HCL, involving multiple pathways with the "PPARα-RORγ-SREBP2" being a potential complex player in this hepatic cholesterol biosynthesis programming.

Desmosterol: A natural product derived from macroalgae modulates inflammatory response and oxidative stress pathways in intestinal epithelial cells

“…Total RNA extracted from IPI-2I cells using TRIzol Reagent (Takara Biotech, Dalian, China) was reverse-transcribed into cDNA using HiScript ® II Q Select R.T. SuperMix (Vazyme, Nanjing, China) according to the manufacturer’s instructions and previous report ( 12 , 13 ). qRT-PCR analysis was performed by an ABI StepOne Plus Real-Time PCR System (Applied Biosystems, CA, USA) using AceQ ® qPCR SYBR Green Master Mix (Vazyme, Nanjing, China).…”

Hepatic Anti-Oxidative Genes CAT and GPX4 Are Epigenetically Modulated by RORγ/NRF2 in Alphacoronavirus-Exposed Piglets

“…Cold PBS was used to wash the liver tissues randomly selected from the PEDV-infected and uninfected piglets. In order to prepare the total RNA for RNA-seq, Illumina Tru-Seq RNA Sample Preparation Kit was used as previously described [ 31 ]. Firstly, the quality of libraries should be eligible, and an Agilent 2100 Bioanalyzer was used to check it.…”

“…As in a previous description [ 31 , 35 ], ChIP-qPCR was performed with the following modifications. In short, 1% formaldehyde was used to cross-link liver tissues for 5 min, then the fixing buffer containing 100 mmol/L NaCl, 50 mmol/L Hepes-KOH, 1 mmol/L EDTA, and 0.5 mol/L EGTA was used for pulverizing and resuspending.…”

Nuclear Receptor RORα/γ: Exciting Modulators in Metabolic Syndrome and Related Disorders

“…Moreover, ectopic RORγ overexpression performed similar effects with those of the agonists possibly via epigenetically recruited histone active marks H3K27ac. A recent study also revealed RORγ as an essential mediator in facilitating the interaction of PPARα and SREBP2 and in controlling the cholesterol biosynthesis genes transcription ( 62 ). This new complex of “PPARα-RORγ-SREBP2” explored a new mechanism on cholesterol reprogramming in a context and cell-type-specific manner, which would be beneficial for the invention of therapeutic strategy for MetS and related metabolic diseases.…”

“…This new complex of “PPARα-RORγ-SREBP2” explored a new mechanism on cholesterol reprogramming in a context and cell-type-specific manner, which would be beneficial for the invention of therapeutic strategy for MetS and related metabolic diseases. Indeed, PPARα plays a novel role in MetS because of the changed functions induced by RORγ in different scenarios, suggesting the complicated crosstalk among these NRs ( 62 , 63 ). Given the fact that LXRs modulate the cholesterol intake and efflux by the key enzymes such as LDLR and ABCA1/G1, it is suggested that a diminished RORγ availability is associated with decreased cholesterol production in response to LXR activation ( 53 , 55 , 64 ).…”