Effect of SIRT1 regulating Nrf2/HO-1 signaling pathway on sepsis-induced acute lung injury / 中华危重病急救医学

Objective:To investigate whether silence information regulator 1 (SIRT1) could regulate nuclear factor E2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) signaling pathway and its role in acute lung injury (ALI) in sepsis rats.Methods:Twenty-four male Sprague-Dawley (SD) rats were randomly divided into sham operation group (Sham group), cecal ligation and puncture (CLP) induced sepsis group (CLP group), sepsis+SIRT1 specific agonist group (CLP+SRT1720 group,10 mg/kg SRT1720 was intraperitoneally injected 2 hours before CLP), sepsis+SIRT1 specific inhibitor group (CLP+EX527 group, 10 mg/kg EX527 was intraperitoneally injected 2 hours before CLP), with 6 rats in each group. The rats were killed 24 hours after modeling and their lung tissues were taken for pathological score (Smith score), superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), tumor necrosis factor-α (TNF-α), interleukins (IL-6, IL-1β), and SIRT1, Nrf2 and HO-1 mRNA and protein expression were detected.Results:The lung tissue of the CLP group mice was severely damaged, the alveolar interval was widened and a large number of inflammatory cells infiltrated, and there was visible pulmonary capillary hyperemia. The Smith score, the levels of TNF-α, IL-6, IL-1β, MDA and 8-OHdG were significantly increased, the levels of SOD, GSH, SIRT1, Nrf2 and HO-1 were significantly decreased in CLP group. After using SIRT1 specific agonist, the lung injury in CLP+SRT1720 group was significantly alleviated compared with that in CLP group, Smith score and lung tissue TNF-α, IL-6, and IL-1β levels were significantly decreased [Smith score: 2.83±0.75 vs. 5.67±0.52, TNF-α (ng/L): 36.78±5.36 vs. 66.99±5.44, IL-6 (ng/L): 23.97±3.76 vs. 45.70±4.16, IL-1β (ng/L): 16.76±1.39 vs. 39.64±2.59, all P < 0.05], SOD activity and GSH content increased [SOD (kU/g): 115.88±3.31 vs. 101.65±1.09, GSH (μmol/g): 8.42±0.81 vs. 5.74±0.46, both P < 0.05], MDA and 8-OHdG contents decreased [MDA (μmol/g): 5.24±0.33 vs. 9.86±0.66, 8-OHdG (ng/L): 405.76±8.54 vs. 647.12±10.64, both P < 0.05], the mRNA and protein expressions of SIRT1, Nrf2 and HO-1 were increased [SIRT1 mRNA (2 -ΔΔCT): 1.49±0.15 vs. 0.64±0.03, Nrf2 mRNA (2 -ΔΔCT): 1.19±0.08 vs. 0.84±0.02, HO-1 mRNA (2 -ΔΔCT): 1.80±0.41 vs. 0.64±0.11, SIRT1 protein (SIRT1/β-actin): 1.03±0.06 vs. 0.52±0.05, Nrf2 protein (Nrf2/β-actin): 1.14±0.10 vs. 0.63±0.05, HO-1 protein (HO-1/β-actin): 1.01±0.11 vs. 0.73±0.03, all P < 0.05]. The lung injury in CLP+EX527 group was more severe than that in CLP group, Smith score and lung tissue TNF-α, IL-6, IL-1β levels were significantly increased [Smith score: 8.00±0.89 vs. 5.67±0.52, TNF-α (ng/L): 87.15±4.23 vs. 66.99±5.44, IL-6 (ng/L): 66.79±2.93 vs. 45.70±4.16, IL-1β (ng/L): 58.99±2.12 vs. 39.64±2.59, all P < 0.05], SOD activity and GSH content decreased [SOD (kU/g): 72.84±3.85 vs. 101.65±1.09, GSH (μmol/g): 3.30±0.67 vs. 5.74±0.46, both P < 0.05], the contents of MDA and 8-OHdG were increased [MDA (μmol/g): 14.14±0.70 vs. 9.86±0.66, 8-OHdG (ng/L): 927.66±11.47 vs. 647.12±10.64, both P < 0.05], the mRNA and protein expressions of SIRT1, Nrf2 and HO-1 were decreased [SIRT1 mRNA (2 -ΔΔCT): 0.40±0.07 vs. 0.64±0.03, Nrf2 mRNA (2 -ΔΔCT): 0.48±0.07 vs. 0.84±0.02, HO-1 mRNA (2 -ΔΔCT): 0.27±0.14 vs. 0.64±0.11, SIRT1 protein (SIRT1/β-actin): 0.20±0.05 vs. 0.52±0.05, Nrf2 protein (Nrf2/β-actin): 0.45±0.01 vs. 0.63±0.05, HO-1 protein (HO-1/β-actin): 0.36±0.08 vs. 0.73±0.03, all P < 0.05]. Conclusions:In the rat model of ALI induced by sepsis, SIRT1 can regulate the activation of Nrf2/HO-1 signaling pathway, upregulate the expression of downstream antioxidant enzymes, reduce oxidative stress injury, and then alleviate the ALI induced by sepsis in rats.

Construction of a prediction model for postoperative prognosis in patients with resectable cholangiocarcinoma based on SIRT2 expression / 浙江大学学报·医学版

OBJECTIVES@#To develop a prediction model for postoperative prognosis in patients with cholangiocarcinoma (CCA) based on the expression of silence information regulator 2 (SIRT2).@*METHODS@#The differential expression of SIRT2 between CCA and normal tissues was analyzed using TCGA and GEO databases. Gene set enrichment analysis (GSEA) was used to explore potential mechanisms of SIRT2 in CCA. The expression of SIRT2 protein in CCA tissues and normal tissues (including 44 pairs of specimens) was also detected by immunohistochemistry (IHC) staining in 89 resectable CCA patients who underwent surgical treatment in The First Affiliated Hospital of Bengbu Medical College between January 2016 and December 2021. The relationship between SIRT2 expression and clinicopathological characteristics and prognosis of CCA patients was analyzed. A survival prediction model for patients with resectable CCA was constructed with COX regression results, the calibration curve and the time-dependent receiver operating characteristic curve (ROC) were used to evaluate the performance of the constructed model, and the predictive power between this model and the AJCC/TNM staging system (8th Edition) was compared.@*RESULTS@#SIRT2 mRNA was overexpressed in CCA tissues as shown in TCGA and GEO databases. IHC staining showed that SIRT2 protein expression in CCA tissues was significantly higher than that in adjacent non-tumor tissues. GSEA results showed that elevated SIRT2 expression may be involved in multiple metabolism-related signaling pathway, such as fatty acid metabolism, oxidative phosphorylation, amino acid metabolism, etc. SIRT2 expression level was related to serum triglycerides level, tumor size and lymph node metastasis (all P<0.05). The survival analysis results showed that the patients with higher SIRT2 expression had a significant lower overall survival (OS) than patients with lower SIRT2 expression (P<0.05). Univariate COX regression analysis suggested that pathological differentiation, clinical stage, postoperative treatment and SIRT2 expression level were associated with the prognosis of CCA patients (all P<0.05). Multivariate regression analysis confirmed that clinical stage and SIRT2 expression level were independent predictors of OS in postoperative CCA patients (both P<0.05). A nomogram based on SIRT2 for prediction of survival in postoperative CCA patients was constructed. The C-index of the model was 0.675, and the area under the time-dependent ROC curve (AUC) for predicting survival in the first, second, and third years was 0.879, 0.778, and 0.953, respectively, which were superior to those of AJCC/TNM staging system (8th Edition).@*CONCLUSIONS@#SIRT2 is highly expressed in CCA tissues, which is associated with poor prognosis in patients with resectable CCA. The nomogram developed based on SIRT2 may have better predictive power than the AJCC/TNM staging system (8th Edition) in prediction of survival of postoperative CCA patients.

Effect of Huluan Decoction on SIRT1/NF-κB/p53/p21 Pathway in Model Mice with Premature Ovarian Insufficiency / 中国实验方剂学杂志

Objective:To observe the effects of Huluan decoction on the expression of apoptosis-related protein silence information regulator 1 （SIRT1）， tumor suppressor gene （p53）， acetylated p53 （Ac-p53）， cyclin-dependent kinase inhibitor （p21）， and nuclear factor-<italic>κ</italic>B （NF-<italic>κ</italic>B） p65 and changes in ovarian tissue structure of a mouse model with premature ovarian insufficiency （POI） induced by tripterygium glycosides. Method:Fifty female C57BL/6J mice were randomly divided into the blank group， model group， low- and high-dose Huluan decoction groups， and western medicine （estradiol valerate） group. After intragastric administration of tripterygium glycosides at 80 mg·kg^-1·d^-1 for 14 successive days， mice in the low- and high-dose Huluan decoction groups and western medicine group were treated with Huluan decoction at 1.6 g·kg^-1·d^-1 and 6.2 g·kg^-1·d^-1 and estradiol valerate at 0.13 mg·kg^-1·d^-1， respectively， by gavage since the 15^th day， while those in the blank group were provided with an equal amount of distilled water for 21 consecutive days. Following the last administration， the blood was sampled for detecting the levels of serum anti-Müllerian hormone （AMH）， follicle-stimulating hormone （FSH）， and luteinizing hormone （LH） by ELISA and the ovary was harvested for observing the morphological changes by HE staining. The mRNA expression levels of p53 and p21 were measured by Real-time polymerase chain reaction （Real-time PCR）， and the protein expression levels of SIRT1， p53， p21， Ac-p53， NF-<italic>κ</italic>B were assayed by Western blot. Result:Compared with the blank group， the model group exhibited a disordered estrous cycle， diminished ovarian volume， decreased number of follicles at various developmental stages， reduced AMH， and elevated FSH and LH， and elevated p53，p21，Ac-p53，NF-<italic>κ</italic>B protein expression and p53，p21 mRNA， reduced SIRT1 protein expression（<italic>P</italic><0.01）. As revealed by the comparison with the model group， each medication group displayed an increased number of follicles， elevated AMH， reduced FSH and LH （<italic>P</italic><0.01）， up-regulated SIRT1 protein expression （<italic>P</italic><0.01）， and significantly down-regulated mRNA and protein expression of aging-related genes p53， p21， and down-regulated Ac-p53，NF-<italic>κ</italic>B protein expression （<italic>P</italic><0.01）. Conclusion:Huluan decoction significantly reverses the aging process and improves ovarian function possibly by boosting the activity of SIRT1/NF-<italic>κ</italic>B/p53/p21 pathway in ovarian cells， changing the apoptotic state， increasing the growing and mature follicles， and reducing the atretic follicles.

Progress on mitochondrial silence information regulator family in epilepsy / 浙江大学学报·医学版

SIRT3, SIRT4 and SIRT5 are located in mitochondria and also known as mitochondrial sirtuins. They play important roles in regulating many cellular functions including cell survival, cell cycle or apoptosis, DNA repair and metabolism. Mitochondrial sirtuins are involved in the protection of mitochondrial integrity and energy metabolism under stress regulating the expression of neurotransmitter receptors, neurotrophins, extracellular matrix proteins and various transcription factors, thus involved in epileptogenesis triggered by both genetic or acquired factors. Here we review research progress on the actions of mitochondrial sirtuin in epilepsy; and discuss the challenges and perspectives of mitochondrial sirtuin as a potential therapeutic target for epilepsy.

Advances in the role of silence information regulator family in pathological pregnancy / 浙江大学学报·医学版

Aberrant maternal inflammation and oxidative stress are the two main mechanisms of pathological pregnancy. The silence information regulator (sirtuin) family is a highly conserved family of nicotinamide adenine dinucleotide (NAD)-dependent deacylases. By regulating the post-translational modification of proteins, sirtuin is involved in various biological processes including oxidative stress and inflammation. Nowadays, emerging evidence indicates that sirtuin may be closely related to the occurrence and development of pathological pregnancy. The down-regulation of sirtuin can cause spontaneous preterm delivery by promoting uterine contraction and rupture of fetal membranes, cause gestational diabetes mellitus through promoting oxidative stress and affecting the activity of key enzymes in glucose metabolism, cause preeclampsia by reducing the proliferation and invasion ability of trophoblasts, cause intrahepatic cholestasis of pregnancy by promoting the production of bile acids and T helper 1 cell (Th1) cytokines, and cause intrauterine growth restriction through inducing mitochondrial dysfunction. Moreover, the expression and activation of sirtuin can be modulated through dietary interventions, thus sirtuin is expected to become a new target for the prevention and treatment of pregnancy complications. This article reviews the role of the sirtuin family in the occurrence and development of pathological pregnancy and its influence on the development of the offspring.