A novel HDAC6 inhibitor attenuate APAP-induced liver injury by regulating MDH1-mediated oxidative stress

Glutathione (GSH) depletion, mitochondrial damage, and oxidative stress have been implicated in the pathogenesis of acetaminophen (APAP) hepatotoxicity. Here, we demonstrated that the expression of histone deacetylase 6 (HDAC6) is highly elevated, whereas malate dehydrogenase 1 (MDH1) is downregulated in liver tissues and AML-12 cells induced by APAP. The therapeutic benefits of LT-630, a novel HDAC6 inhibitor on APAP-induced liver injury, were also substantiated. On this basis, we demonstrated that LT-630 improved the protein expression and acetylation level of MDH1. Furthermore, after overexpression of MDH1, an upregulated NADPH/NADP+ ratio and GSH level and decreased cell apoptosis were observed in APAP-stimulated AML-12 cells. Importantly, MDH1 siRNA clearly reversed the protection of LT-630 on APAP-stimulated AML-12 cells. In conclusion, LT-630 could ameliorate liver injury by modulating MDH1-mediated oxidative stress induced by APAP.

miR-126-5p targets Malate Dehydrogenase 1 in non-small cell lung carcinomas

Malate Dehydrogenase (MDH) 1 has recently been shown to be highly expressed and display prognostic value in non-small cell lung carcinomas (NSCLCs). However, it is not known how MDH1 expression is regulated and there is no current molecular or chemical strategy that specifically targets MDH1. This may be due to structural and enzymatic similarities with its isoenzyme, malate dehydrogenase 2 (MDH2). However, MDH1 and MDH2 are encoded by distinct genes and this opens up the possibility for modulation at the expression level. Here, we screened in silico for microRNAs (miRs) that selectively targets the 3'UTR region of MDH1. These analyses revealed that mir-126-5p has three binding sites in the 3'UTR region of MDH1. Additionally, we show that expression of miR-126-5p suppresses the enzymatic activity of MDH1, mitochondrial respiration and caused cell death in NSCLC cell lines.