Background & Aims p53 and its transcriptional target miRNA34a have been implicated in the pathogenesis of fatty liver. We tested the efficacy of a p53 inhibitor, pifithrin-α p-nitro (PFT) in attenuating steatosis, associated oxidative stress and apoptosis in a murine model of non-alcoholic fatty liver disease (NAFLD). Methods C75Bl/6J mice were fed a high-fat (HFD) or control diet for 8 weeks, PFT or DMSO (vehicle) were administered three times per week. Markers of oxidative stress and apoptosis as well as mediators of hepatic fatty acid metabolism were assessed by immunohistochemistry, Western-blot, real-time PCR and biochemical assays. Results PFT administration suppressed HFD-induced weight gain, ALT elevation, steatosis, oxidative stress and apoptosis. PFT treatment blunted the HFD-induced upregulation of miRNA34a and increased SIRT1 expression. In the livers of HFD-fed, PFT-treated mice activation of the SIRT1/PGC1α/PPARα axis increased the expression of malonyl-CoA decarboxylase (MLYCD), an enzyme responsible for malonyl-CoA (mCoA) degradation. Additionally, the SIRT1/LKB1/AMPK pathway (upstream activator of MLYCD) was promoted by PFT. Thus, induction of these two pathways by PFT diminished the hepatic mCoA content by enhancing MLYCD expression and function. Since mCoA inhibits carnitine palmitoyltransferase 1 (CPT1), the decrease of hepatic mCoA in the PFT-treated, HFD-fed mice increased CPT1 activity, favored fatty acid oxidation and decreased steatosis. Additionally, we also demonstrated that PFT abrogated steatosis and promoted MLYCD expression in palmitoleic acid- treated human HepaRG cells. Conclusions The p53 inhibitor PFT diminished hepatic triglyceride accumulation and lipotoxicity in mice fed a HFD by depleting mCoA and favoring the β-oxidation of fatty acids.

Introduction: Saphenous veins (SVs) are frequently used in CABG surgery, but over 50% of the SV grafts fail in the first 10 years after surgery due to neointima formation. Long non-coding RNAs (lncRNAs) have emerged as attractive therapeutic targets and biomarkers for cardiovascular disease. However, studies on their role and mechanisms in humans are limited. This study aimed to unravel epigenetic mechanisms of neointima formation in human SVs and investigate the role of candidate lncRNAs in key vascular cell functions pertinent to neointima formation. Methods and Results: By using an ex vivo model of human SV graft disease wherein segments of human SV are incubated in tissue culture, we performed RNA-sequencing on human SV with and without neointima formation to interrogate the global transcriptomic changes, and determined 699 differentially expressed novel lncRNAs during neointimal formation. We then identified BAZ1A-antisense (AS)1 as a novel lncRNA highly upregulated during neointima formation. BAZ1A-AS1 overlaps antisense to its cis- regulatory gene, BAZ1A , which was reported to play a role in oxidative stress and DNA damage repair response. We found that one isoform of BAZ1A-AS1 primarily localizes to the nucleus of VSMCs. Interestingly, UV exposure of vascular smooth muscle cells (VSMCs) isolated from human SV induced significant upregulation of BAZ1A and BAZ1A-AS1, suggesting that BAZ1A-AS1 could be associated with chromatin repair processes activated during neointima formation. To investigate whether BAZ1A-AS1 can regulate VSMC functions pertinent to neointima formation, VSMCs were transfected with BAZ1A-AS1 antisense gapmers. Knockdown of BAZ1A-AS1 showed reduced cell proliferation and migration, and increased cell death and DNA damage in VSMCs. Furthermore, role of BAZ1A during neointima formation in vivo is currently under investigation in a carotid artery ligation model using BAZ1A knockout mice. Conclusions: We identified BAZ1A-AS1 as a novel lncRNA associated with neointima formation in human SV, and targeted inhibition of BAZ1A-AS1 or its cis-regulator gene BAZ1A could be a promising strategy for SV graft disease.

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