Rationale: Over 50% of heart failure patients have preserved, rather than reduced ejection fraction (HFpEF vs. HFrEF). Complexity of its pathophysiology and the lack of animal models hamper the development of effective therapy for HFpEF. Objective: This study was designed to investigate the metabolic mechanisms of HFpEF and test therapeutic interventions using a novel animal model.Methods and Results: By combining the age, long-term high-fat diet and desoxycorticosterone pivalate challenge in a mouse model we were able to recapture the myriad features of HFpEF. In these mice, mitochondrial hyperacetylation exacerbated while increasing ketone body availability rescued the phenotypes. The HFpEF mice exhibited overproduction of interleukin (IL)-1β/IL-18, and tissue fibrosis due to increased assembly of NLPR3 inflammasome on hyperacetylated mitochondria. Increasing β-hydroxybutyrate (β-OHB) level attenuated NLPR3 inflammasome formation and antagonized proinflammatory cytokines-triggered mitochondrial dysfunction and fibrosis. Moreover, β-OHB downregulated the acetyl-CoA pool and mitochondrial acetylation, partially via activation of citrate synthase and inhibition of fatty acid uptake. Conclusions: Therefore, we identify the interplay of mitochondrial hyperacetylation and inflammation as a key driver in HFpEF pathogenesis which can be ameliorated by promoting β-OHB abundance.

Abstract. Propofol is a commonly used intravenous anesthetic in tumor surgery. Recently, studies have confirmed that propofol has an antitumor effect on hepatocellular carcinoma (HCC); however, the molecular mechanism underlying this effect has not been elucidated until now. The present study aimed to investigate the mechanism of propofol on HepG2 cell proliferation, apoptosis and invasion, focusing on High Mobility Group AT-Hook 2 (HMGA2)-mediated Wnt/β-catenin pathway. The HepG2 cells were treated with various concentrations of propofol for 24 h, the relative protein levels of HMGA2, Wnt3a, β-catenin, Snail Family Zinc Finger 1 and c-myc were determined by western blot analysis. HMGA2-pcDNA3.1 plasmid was transfected into the HepG2 cells to overexpress HMGA2. Cell proliferation, apoptosis and invasion were examined by MTT assays, flow cytometry and Transwell-matrigel invasion assays, respectively. The results showed that propofol suppressed HMGA2 expression and Wnt/β-catenin signaling in a dose-dependent manner. Propofol was able to inhibit cell proliferation and invasion, and induce cell apoptosis of HepG2 cells; however, these effects were attenuated by HMGA2 overexpression. The suppressed Wnt/β-catenin signaling in HepG2 cells by treatment with propofol was also reversed by HMGA2 overexpression. In conclusion, this study provided a novel mechanism underlying the anti-tumor function of propofol on HCC. To the best of our knowledge, the present study is the first to demonstrate that propofol could downregulate the expression of HMGA2, which inhibited the Wnt/β-catenin pathway, thus leading to the inhibition of cell proliferation and invasion, as well as the apoptosis of HepG2 cells.

Ischemia-reperfusion (I/R) injury is detrimental to cardiovascular system. Alteration in glucose metabolism has been recognized as an important adaptive response under hypoxic conditions. However, the biological benefits underlying this metabolic phenotype remain to be elucidated. This study was designed to investigate the impact of hypoxic acclimation (HA) on cardiac I/R injury and the antioxidative mechanism(s). Male adult mice were acclimated in a hypoxic chamber (10% oxygen [O 2 ]) for 8 h/day for 14 days, and then subjected to cardiac I/R injury by ligation of left anterior descending coronary artery for 30 min and reperfusion for 24 h or 7 days. Our results showed that HA attenuated oxidative stress and reduced infarct size in the I/R hearts. This cardioprotective effect is coupled with an elevation of protein O-linked N -acetylglucosamine (O-GlcNAc) modification partially due to inflammatory stimulation. Hyperglycosylation activated glucose-6-phosphate dehydrogenase (G6PDH), the rate-limiting enzyme in the pentose phosphate pathway, resulting in an upregulation of NADPH/NADP + and GSH/GSSG couples and enhancement of redox homeostasis in the heart. Pharmacological suppression of O-GlcNAcylation totally abolished the influence of HA on the G6PDH activity, redox balance and post-I/R damage in the hearts and cultured cardiomyocytes, whereby augmentation of O-GlcNAcylation further enhanced the benefits, suggesting a central role of O-GlcNAcylation in HA-initiated antioxidative and cardioprotective effects. These findings, therefore, identified HA as a promising anti-I/R strategy for the heart and proposed O-GlcNAc modification of G6PDH as a therapeutic target in ischemic heart disease.