Sesn2 Levels Research Articles

Sestrin2 prevents age-related intolerance to ischemia and reperfusion injury by modulating substrate metabolism.

A novel stress-inducible protein, Sestrin2 (Sesn2), declines in the heart with aging. AMPK has emerged as a pertinent stress-activated kinase that has been shown to have cardioprotective capabilities against myocardial ischemic injury. We identified the interaction between Sesn2 and AMPK in the ischemic heart. To determine whether ischemic AMPK activation-modulated by the Sesn2-AMPK complex in the heart-is impaired in aging that sensitizes the heart to ischemic insults, young C57BL/6 mice (age 3-4 mo), middle-aged mice (age 10-12 mo), and aged mice (age 24-26 mo) were subjected to left anterior descending coronary artery occlusion for in vivo regional ischemia. The ex vivo working heart system was used for measuring substrate metabolism. The protein level of Sesn2 in hearts was gradually decreased with aging. Of interest, ischemic AMPK activation was blunted in aged hearts compared with young hearts (P < 0.05); the AMPK downstream glucose uptake and the rate of glucose oxidation were significantly impaired in aged hearts during ischemia and reperfusion (P < 0.05 vs. young hearts). Myocardial infarction size was larger in aged hearts (P < 0.05 vs. young hearts). Immunoprecipitation with Sesn2 Ab revealed that cardiac Sesn2 forms a complex with AMPK and upstream liver kinase B1 (LKB1) during ischemia. Of interest, the binding affinity between Sesn2 and AMPK upstream LKB1 is impaired in aged hearts during ischemia (P < 0.05 vs. young hearts). Furthermore, Sesn2-knockout hearts demonstrate a cardiac phenotype and response to ischemic stress that is similar to wild-type aged hearts (i.e., impaired ischemic AMPK activation and higher sensitivity to ischemia- and reperfusion- induced injury). Adeno-associated virus-Sesn2 was delivered to aged hearts via a coronary delivery approach and significantly rescued the protein level of Sesn2 and the ischemic tolerance of aged hearts; therefore, Sesn2 is a scaffold protein that mediates AMPK activation in the ischemic myocardium via an interaction with AMPK upstream LKB1. Decreased Sesn2 levels in aging lead to a blunted ischemic AMPK activation, alterations in substrate metabolism, and an increased sensitivity to ischemic insults-Quan, N., Sun, W., Wang, L., Chen, X., Bogan, J. S., Zhou, X., Cates, C., Liu, Q., Zheng, Y., Li J. Sestrin2 prevents age-related intolerance to ischemia and reperfusion injury by modulating substrate metabolism.

Sestrins increase in patients with coronary artery disease and associate with the severity of coronary stenosis

BackgroundSestrins (Sesns) family, which including three members Sesn1, Sesn2 and Sesn3, is known as stress-inducible proteins and participate in multiple diseases via regulating oxidative stress, inflammatory response and cell apoptosis. The present study aimed to investigate the plasma levels and the clinical significance of Sesns in patients with coronary artery disease (CAD). MethodsIn the case-control study, 119 CAD patients, including stable angina pectoris (SAP, n=44), unstable angina pectoris (UAP, n=41) and acute myocardial infarction (AMI, n=29) were included. Patients with chest pain syndrome but excluded CAD (n=35) were enrolled as control. Plasma levels of Sesn1, Sesn2, Sesn3, superoxide dismutase (SOD) and malondialdehyde (MDA) in all patients were measured and analyzed. ResultsCompared with control group, plasma levels of Sesn1, Sesn2 and Sesn3 were significantly increased in patients with SAP, UAP and AMI. In addition, a significant lower SOD levels and higher MDA levels were observed in CAD patients, Sesn1/2/3 levels were negatively correlated with SOD levels and positively correlated with MDA levels. Gensini Score were positively correlated with Sesn1/2/3 levels and MDA levels, whereas negatively correlated with SOD levels. Furthermore, as the main risk factors for CAD, the elderly and obesity increased plasma Sesn2 levels, diabetes increased both plasma Sesn2 and Sesn3 levels. ConclusionsOur study was the first to report that the plasma Sesns levels were increased in CAD patients and positively related to the severity of coronary heart disease. Although the exact mechanisms of Sesns in CAD are still unknown, alleviated oxidative stress may be the possible reasons.

Potential role of mitochondrial ROS in Sestrin2 degradation

Sestrin2 (SESN2) is a stress-inducible antioxidant protein that controls redox-homeostasis via its oxidoreductase activity. Although the induction mechanism of SESN2 has been reported, the mechanism for regulation of SESN2 protein stability has not yet been elucidated. In the present study, we investigated the role of mitochondrial reactive oxygen species (ROS) in the degradation of SESN2 and the related mechanism. First, we found that rotenone, an inhibitor of mitochondrial complex I, significantly lowered the SESN2 protein level in hepatocytes. In addition, antimycin A (an inhibitor of mitochondrial complex III) and Mn-TBAP (a superoxide dismutase mimetic) were also shown to reduce SESN2. Rotenone decreased mitochondrial ROS; this result implied that mitochondrial ROS production was involved in SESN2 regulation. However, the level of SESN2 mRNA was unchanged by rotenone treatment. Next, SESN2 protein stability was observed after treatment with cycloheximide and rotenone. Decreased SESN2 protein stability was detected in the presence of cycloheximide, and rotenone accelerated this SESN2 decay. MG132 (a proteasome inhibitor) treatment causes significant accumulation of SESN2 protein, but rotenone still reduced SESN2 levels in the presence of MG132. However, chloroquine, a lysosomal inhibitor, restored rotenone-reduced SESN2 levels. These results suggest that mitochondrial ROS prevent SESN2 protein degradation, and this is dependent on lysosomal activity.

5-Fluorouracil inhibits cell migration by induction of Sestrin2 in colon cancer cells.

5-Fluorouracil (5-FU) is a chemotherapeutic agent used in the treatment of colorectal cancer. In this study, we investigated whether 5-FU induces Sestrin2 (SESN2), an antioxidant enzyme, and the role of SESN2 in 5-FU action in colon cancer cells. We found that 5-FU upregulated SESN2 protein expression in both HCT116 and HT29 cells. It also increased transcripts of SESN1 and SESN2, but not of SESN3. Furthermore, we investigated whether production of reactive oxygen species (ROS) was involved in 5-FU-induced SESN2 expression.5-FU did not increase ROS production nor affect Nrf2 phosphorylation and expression levels. Moreover, SESN2 upregulation by 5-FU was not prevented by pretreatment with antioxidants. Next, we investigated p53 levels after 5-FU treatment to elucidate the regulation of SESN2 by 5-FU. An increase in p53 levels was detected following 5-FU treatment; pifithrin-α, an inhibitor of p53 activation, reversed 5-FU-induced SESN2 expression.5-FU prevented serum-induced in vitro cell migration, but knockdown of SESN2 or treatment with pifithrin-α reversed a 5-FU-mediated decrease in cell migration. Taken together, our results suggest that 5-FU increases SESN2 levels via a p53-dependent pathway, which contributes to inhibition of cancer cell migration in vitro.

Sestrin-2 is significantly increased in malignant pleural effusions due to lung cancer and is potentially secreted by pleural mesothelial cells

ObjectivesSestrin-2 (Sesn2) belongs to a family of highly conserved antioxidant proteins that were discovered as p53-inducible proteins and inhibits cell growth and proliferation. Our aim was to assess the levels of Sesn2 in malignant pleural effusions of lung cancer patients compared to benign pleural effusions. Design and methodsWe enrolled 73 patients (55/males and 18/females) diagnosed with pleural effusion (PE). PEs were grouped as 44 malignant pleural effusions (MPEs; lung cancer) and 29 benign (BPE; 7 congestive heart failure, 9 tuberculosis, 13 parapneumonic). Pleural fluid (PF) Sesn2 levels were determined by enzyme-linked immunosorbent assay (ELISA) kit. Standard biochemical PF analysis was also performed and Sesn2 levels were correlated with PF lactate dehydrogenase (LDH), protein, cell counts and age. ResultsSesn2 was detected in 24/44 patients with MPEs and in 3/29 patients with BPEs (p=0.0001). The mean value (mean±SEM) of Sesn2 in patients with MPEs was 0.54±0.22ng/mL while in BPEs it was 0.12±0.04ng/mL (p=0.0004). In MPEs Sesn2 pleural fluid levels did not correlate with PF LDH and cell counts (p=0.89 and p=0.64 respectively). ConclusionsOur study shows that Sesn2 is significantly increased in MPEs compared to BPEs. Moreover, the lack of correlation of Sesn2 levels with PF cell counts and PF LDH suggests that it is potentially secreted by pleural mesothelial cells.

Upregulation of Sestrin-2 Expression via P53 Protects Against 1-Methyl-4-Phenylpyridinium (MPP+) Neurotoxicity

Sestrin-2 (SESN2) is a conserved antioxidant protein that is activated upon oxidative stress and protects cells against reactive oxygen species (ROS). However, the role of SESN2 in neurodegenerative diseases, especially in Parkinson's disease (PD), has not yet been elucidated. In this study, we found that expression of SESN2 is elevated in the midbrain of patients with PD. Moreover, in vitro experiments display that the drug 1-methyl-4-phenylpyridinium (MPP+) induces the expression of SESN2 in SH-SY5Y cells in a time- and dose-dependent manner. Our results show that p53 is activated by MPP+. Importantly, inhibition of p53 using small RNA interferences abolishes the increased SESN2 levels induced by MPP+, suggesting that the inductive effect of MPP+ on SESN2 is mediated by p53. Furthermore, knockdown of SESN2 using small RNA interferences promotes MPP+-related neurotoxicity by attenuating oxidative stress, mitochondrial dysfunction, and apoptosis. All these data imply that the induction of SESN2 produces a protective effect in PD.

1,25-Dihydroxyvitamin D3 and the aging-related Forkhead Box O and Sestrin proteins in osteoblasts

Forkhead Box O (FoxO) transcription factors and Sestrins (SESN) are highly conserved and related stress-responsive proteins that protect the organism against age-related pathologies. For FoxOs, growing evidence shows a crucial role in osteoblast function. Here we investigated the role of different FoxO and SESN isoforms in 1,25(OH)2D3-treated MC3T3-E1 osteoblasts. 1,25(OH)2D3 rapidly and strongly induced the expression of SESN1 and FoxO3a but down-regulated the expression of SESN3 and FoxO1. SESN2 and FoxO4 levels were hardly affected by 1,25(OH)2D3. Chromatin Immunoprecipitation (ChIP)-sequencing revealed significant VDR/RXR binding to a DR3-type VDRE in SESN1 but not in the genomic region where FoxO3a is located. Mutation of the SESN1 VDRE abolished responsiveness to 1,25(OH)2D3 in luciferase-based transfection assays. siRNA-mediated knock-down of SESN1, SESN3, FoxO1 or FoxO3a did not prevent 1,25(OH)2D3 from reducing the expression of cell cycle markers like Cyclin D1 and Cdc6 and from exerting its characteristic antiproliferative effect on MC3T3-E1 osteoblasts. Accordingly, the 1,25(OH)2D3-induced reduction in the number of S-phase cells was also maintained. The antiproliferative effect was still present in primary osteoblast in which all three FoxO isoforms were deleted (TKOpOB). Interestingly, both MC3T3-E1 osteoblasts in which FoxO1 was knocked-down and TKOpOBs accumulated significantly more reactive oxygen species (ROS) after treatment with 1,25(OH)2D3 than control cells. siRNA-mediated knock-down of individual SESN isoforms did not result in significant differences in ROS levels. In conclusion, 1,25(OH)2D3 directly and indirectly alters the expression levels of different FoxO and SESN isoforms in osteoblasts, presumably not to exert its antiproliferative action but to control ROS levels.This article is part of a Special Issue entitled ‘Vitamin D Workshop’.