Sestrin1 is involved in the regulation of gluconeogenesis in mouse liver cells / 基础医学与临床

Objective To investigate the role and regulatory mechanism of stress-inducing protein 1(SESN1)in liver gluconeogenesis of fasting mice.Methods RT-qPCR was used to detect mRNA expression of SESN1 in liver tissues of C57BL/6J mice and primary mouse hepatocytes treated with forskolin(Fsk)and dexamethasone(Dex).HepG2 cells were transfected with plasmids and the effects of SESN1 overexpression on mRNA expression of gluconeogenesis related genes PGC-1α,PEPCK and G6Pase was detected by RT-qPCR.The effect of SESN1 on the promoter activity of PGC-1α in HepG2 cells was studied using a dual luciferase reporter system.The effect of SESN1 on PGC-1α deacetylation was detected by overexpression of SESN1 and inhibition of SIRT1 expression.By knocking down SIRT1 expression,we detected whether it mediated the changes in mRNA levels of SESN1 in-duced gluconeogenesis related genes.Results The mRNA expression of SESN1 was significantly increased in liver tissues of starved C57BL/6J mice and in primary hepatocytes treated with Fsk and Dex(P<0.001).Over-expression of SESN1 in HepG2 cells promoted mRNA expression of PGC-1α,PEPCK and G6Pase(P<0.001)and promoter activity of PGC-1α(P<0.001).Over-expression of SESN1 decreased the acetylation level of PGC-1α in primary hepatocytes.Sirt family inhibitors NAM and shRNA adenovirus interfered with SIRT1 expression respective-ly,and antagonized the deacetylation effect of SESN1 on PGC-1α.The expression of PGC-1α,PEPCK and G6Pase induced by SIRT1 was also significantly impaired(P<0.000 1).Conclusions SESN1 regulates liver gluconeogene-sis in mice with a SIRT1-dependent mechanism.

Pre-treatment of the beta3-adrenergic receptor agonist BRL37344 reduces in vivo myocardial ischemia/reperfusion injury by improving AMPK and SIRT1 activity and by suppressing mTOR and p70S6K signaling pathways

Abstract This study aimed to investigate the role and signaling pathways of β3-AR in myocardial ischemia/reperfusion (I/R) injury, which is one of the leading causes of death worldwide. 47 male rats were randomly divided into two main groups to evaluate infarct size and molecular parameters. Rats in both groups were randomly divided into 4 groups. Control (sham), I/R (30 min ischemia/120 min reperfusion), BRL37344 (BRL) (A) (5 µg/kg single-dose pre-treatment (preT) before I/R) and BRL (B) (5 µg/kg/day preT for 10 days before I/R). Infarct size was determined with triphenyltetrazolium chloride staining and analyzed with ImageJ program. The levels of AMPK, SIRT1, mTOR, and p70SK6 responsible for cellular energy and autophagy were evaluated by western blot. Infarct size increased in the I/R group (44.84 ± 1.47%) and reduced in the single-dose and 10-day BRL-treated groups (32.22 ± 1.57%, 29.65 ± 0.55%; respectively). AMPK and SIRT1 levels were decreased by I/R but improved in the treatment groups. While mTOR and p70S6K levels increased in the I/R group, they decreased with BRL preT. BRL preT protects the heart against I/R injury. These beneficial effects are mediated in part by activation of AMPK and SIRT1, inhibition of mTOR and p70S6K, and consequently protected autophagy.

Role of SIRT1 in hematologic malignancies / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Sirtuin 1 (SIRT1) is a protein deacetylase, which regulates various physiological activities by deacetylating different protein substrates. An increasing number of studies have revealed critical roles of SIRT1 in different aspects of cancers including metabolism, proliferation, genomic instability, and chemotherapy resistance. Depending on the protein targets in a certain oncogenic context, SIRT1 may play a unique role in each individual blood cancer subtype. Our previous work showed that activation of SIRT1 in primitive leukemia cells of acute myeloid leukemia (AML) and chronic myelogenous leukemia (CML) promotes disease maintenance. On the other hand, an SIRT1 agonist was shown to disrupt maintenance of myelodysplastic syndrome (MDS) stem cells and holds promise as a potential therapeutic approach. Herein, we present a concise summary of the different functions of SIRT1 in hematologic malignancies.

Role of SIRT1 in hematologic malignancies / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Sirtuin 1 (SIRT1) is a protein deacetylase, which regulates various physiological activities by deacetylating different protein substrates. An increasing number of studies have revealed critical roles of SIRT1 in different aspects of cancers including metabolism, proliferation, genomic instability, and chemotherapy resistance. Depending on the protein targets in a certain oncogenic context, SIRT1 may play a unique role in each individual blood cancer subtype. Our previous work showed that activation of SIRT1 in primitive leukemia cells of acute myeloid leukemia (AML) and chronic myelogenous leukemia (CML) promotes disease maintenance. On the other hand, an SIRT1 agonist was shown to disrupt maintenance of myelodysplastic syndrome (MDS) stem cells and holds promise as a potential therapeutic approach. Herein, we present a concise summary of the different functions of SIRT1 in hematologic malignancies.