Irisin通过Sirt1/UCP2拮抗二氯化钴诱导的心肌损伤作用

目的探讨肌肉因子Irisin调节胞内保护蛋白Sirt1和线粒体解偶联蛋白2(uncoupling protein 2,UCP2)在心肌缺氧过程中发挥的作用及具体机制。方法以CoCl_(2)作用H9c2心肌细胞24 h,构建心肌细胞体外缺氧模型。实验分为6组:control组、Irisin 10 nmol·L^(-1)组、Irisin 20 nmol·L^(-1)组、CoCl_(2)模型组、CoCl_(2)+Irisin 10 nmol·L^(-1)治疗组、CoCl_(2)+Irisin 20 nmol·L^(-1)治疗组。CCK-8法检测细胞存活率,Flow cytometry测定细胞凋亡和线粒体膜电位,探针法指示细胞内活性氧(reactive oxygen species,ROS)高低水平,Western blot法检测细胞内Sirt1、UCP2、Bcl-2、Bax、cleaved-caspase3的表达水平。结果心肌细胞H9c2缺氧模型组细胞活力下降、细胞凋亡增多、ROS增加、线粒体膜电位明显下降,同时抗凋亡蛋白Bcl-2、Sirt1和UCP2表达下调,凋亡相关蛋白Bax、cleaved-caspase3表达上调;与模型组相比,Irisin预保护治疗组发挥保护作用呈浓度依赖性,表现为能明显抑制细胞凋亡,改善细胞活力,同时抑制ROS水平,恢复线粒体膜电位,上调保护性蛋白Sirt1、UCP2、Bcl-2的表达,下调介导凋亡的Bax、cleaved caspase-3的表达。结论Irisin通过激活Sirt1/UCP2,进而抑制CoCl_(2)诱导的线粒体膜电位下降,改善氧化应激介导的心肌细胞凋亡。

SIRT1/UCP2通路在白藜芦醇抑制血管内皮细胞氧化应激损伤中的作用

目的观察白藜芦醇对血管内皮细胞氧化应激损伤的抑制作用,并围绕SIRT1/UCP2信号通路探讨其作用机制。方法原代培养人脐静脉内皮细胞(human umbilical vein endothelial cells,HUVECs),用叔丁基过氧化氢(t-BHP)建立HUVECs氧化应激损伤模型。CCK-8法检测细胞增殖,确定半抑制浓度(IC50)。荧光分光光度计检测细胞内活性氧(ROS)生成。CCK-8法检测白藜芦醇对t-BHP诱导的HUVECs活力的影响;qRT-PCR法检测白藜芦醇对SIRT1和UCP2mRNA表达的影响;Western blot法检测白藜芦醇对SIRT1、UCP2和Caspase-3在细胞内蛋白表达的影响。结果 t-BHP明显抑制细胞活力,IC50为80μmol/L。白藜芦醇(0.1、1、10μmol/L)预处理2 h能显著抑制t-BHP诱导的细胞活力下降(P<0.05),并抑制t-BHP诱导的细胞内ROS增加(P<0.05)。同时,白藜芦醇能明显抑制t-BHP诱导的SIRT1的mRNA和蛋白表达下降、UCP2的mRNA和蛋白表达升高及Caspase-3表达增加(P<0.05),而Sirt1抑制剂尼克酰胺能削弱白藜芦醇的抑制作用。结论白藜芦醇可能通过活化SIRT1抑制UCP2表达,削弱t-BHP诱导的细胞内ROS生成,从而抑制血管内皮细胞氧化应激损伤。

SIRT1/UCP2通路在脂肪变性HepG2细胞线粒体能量代谢中的调控机制

目的采用油酸诱导Hep G2细胞发生脂变,建立脂肪变性细胞模型,观察SIRT1/UCP2通路在脂肪变性Hep G2细胞能量代谢中的调控机制。方法采用含有2 mmol/L油酸的DMEM培养基诱导Hep G2细胞24 h后,建立脂肪变性Hep G2细胞模型,并设置对照组比较。以油红O染色观察细胞内脂滴形成状况,并用全自动生化仪检测细胞上清丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)含量和细胞内甘油三酯(TG)含量;采用流式细胞仪测定线粒体膜电位的改变,采用磷钼酸比色试剂盒测定细胞内三磷酸腺苷(ATP)含量,运用Western印迹法检测各组细胞SIRT1和UCP2蛋白的表达。结果与对照组比较,模型组细胞内橘红色脂滴大量形成,且TG含量明显升高(P<0.01),线粒体膜电位及细胞内ATP含量显著降低(P<0.05,P<0.01),SIRT1蛋白表达均显著降低(P<0.05),UCP2蛋白表达显著升高(P<0.01)。结论油酸诱导的脂肪变性Hep G2细胞模型可以出现脂质代谢紊乱和线粒体能量代谢失衡,其机制可能与细胞内SIRT1/UCP2通路的激活有关。

Mechanism of hesperidin improving myocardial ischemia/reperfusion injury in type 2 diabetic rats through SIRT1/Nrf2/HO-1 signaling pathway

Objective:To observe the protective effect of hesperidin on myocardial ischemia/reperfusion injury in type 2 diabetes mellitus and its effect on SIRT1/Nrf2/HO-1 signaling pathway.Methods:50 Sprague-Dawley(SD)rats were randomly assigned to the normal control group(NC),model group,ischemia-reperfusion group(IR),hesperidin group,SIRT1 inhibitor group and hesperidin plus SIRT1 inhibitor group.In addition to NC,the rats in the remaining groups were replicated by intraperitoneal of high-fat diet combined with injection of streptozotocin for type 2 diabetic rats.After then,the myocardial ischemia/reperfusion injury(MIRI)rat model was established by LAd for 30 minutes with 2 hours reperfusion.He staining was used to observe the pathological changes of myocardial tissue,and the levels of serum LDH,CK-MB and SOD,GSH and MDA in myocardial tissue were detected by kit methods,and the expression abundance of related proteins in 4-HNE and SIRT1/Nrf2/HO-1 signal pathway were detected by immunohistochemistry and Western blot;Results:Hesperidin could significantly inhibit cardiomyocyte necrosis and inflammatory cell infiltration,reduce LDH activity,CK-MB and MDA level,and increase SOD activity,GSH and 4-HNE level,the differences were statistically significant when compared with IR group(P<0.01).In addition,compared with the ischemia-reperfusion group,the expressions of SIRT1,Nrf2 and HO-1 proteins in hesperidin group were significantly up-regulated,the differences were statistically significant(P<0.01);Conclusion:Hesperidin inhibits oxidative stress by activating SIRT1/Nrf2/HO-1 signaling pathway,and play a protective effect of myocardial ischemia reperfusion injury in diabetic rats.

Yiqi Yangyin and Huatan Quyu granule can improve skeletal muscle energy metabolism in a type 2 diabetic rat model by promoting the AMPK/SIRT/PGC-1α signalling pathway

Objective:To investigate how Yiqi Yangyin and Huatan Quyu granule (YYHO) improves skeletal muscle insulin resistance in a type 2 diabetic rat model and to discover whether the molecular mechanism is related to the promotion of the AMPK/SIRT/PGC-1α signalling pathway.Methods:Rats were randomly divided into 4 groups:the normal group,the model group,the YYHQ granule group,and the pioglitazone group.The type 2 diabetic rat model was established by feeding a high-fat diet for 5 weeks along with a single intraperitoneal injection of 30 mg/kg streptozotocin (STZ).After modelling successfully,the appropriate drug was intragastrically administered to diabetic rats for 2 weeks,once per day.The YYHQ granule group was given a dose of 4.8 g/kg body weight per day,the pioglitazone group was given a dose of 1.35 mg/kg body weight per day.The doses for both groups were equivalent to the clinical equivalent dose based on a previous study.Other groups were gavaged with the same amount of saline water.Body weight,food intake,water intake,urine volume and grip strength were recorded weekly.The fasting blood glucose(FBG) was determined weekly using blood glucose test strips.The related glucose and lipid metabolism indexes,e.g.,fasting insulin (Fins),glycated haemoglobin (GHb),HOMA-IR,ISI,triglycerides (TG),total cholesterol (TC),high-density lipoprotein cholesterol (HDL-C),low-density lipoprotein cholesterol (LDL-C) and free fatty acid (FFA),were determined using biochemical method.The mRNA expression levels of adenosine monophosphate-activated protein kinase (AMPK),peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α),carnitine palmitoyl transterase-1 (CPT-1),Sirtuin 1 (SIRT1),and Sirtuin 3 (SIRT3) were assessed using quantitative real-time PCR (qRT-PCR).The protein expression levels of creatine kinase (CK),Ca2+ ATPase,α-Actin,AMPK,PGC-1α and CPT-1 were determined using enzyme-linked immunosorbent assay method (ELISA).Results:Body weight decreased significantly (P <.01),food intake,water intake and urine volume increased significantly (P <.01),and grip strength decreased significantly (P <.01) in the model group compared with the normal group.The levels of FBG,Fins,GHb and HOMA-IR increased significantly (P <.01),and the ISI decreased significantly (P <.01) in the model group.The levels of TG,TC,LDL-C and FFA increased significantly (P <.05 or P <.01),and the level of HDL-C decreased significantly (P <.05) in the model group.These changes were reversed after treatment with YYHQ granule or pioglitazone.Compared with the model group,the YYHQ granule and pioglitazone groups significantly improve body weight,water intake and urine volume (P <.05 or P <.01),however,both treatments had no significant effect on food intake (P >.05).The levels of FBG,Fins,GHb,HOMA-IR and ISI were improved significantly (P <.01) and the levels of TG,TC and LDL-C were improved significantly (P <.05 or P <.01),however,both treatments had no significant effect on the levels of HDL-C and FFA (P >.05).Further results indicated that YYHQ granule significantly decreased the mRNA expression of AMPK,PGC-1α,CPT-1,SIRT1 and SIRT3 in skeletal muscle (P <.01) and the pioglitazone group showed similar effects;moreover,the protein expression levels of CK,Ca2+ATPase,α-Actin,AMPK,PGC-1α and CPT-1 in skeletal muscle significantly decreased (P <.01),however,pioglitazone had no significant effect on CK and α-Actin (P >.05).Conclusion:The possible molecular mechanism of YYHQ granule improving skeletal muscle insulin resistance in a type 2 diabetic rat model may be related to the stimulation of energy metabolism in skeletal muscle via the AMPK/SIRT/PGC-1α signalling pathway.

瑞舒伐他汀通过调控UCP2-SIRT3通路减轻脑缺血/再灌注对神经元线粒体的损伤

目的探讨瑞舒伐他汀(rosuvastatin,RS)通过UCP2-SIRT3信号通路在脑缺血/再灌注(CIR)神经元线粒体损伤中的作用及其机制。方法建立SH-SY5Y细胞的脑梗死再灌注模型(OGD/R),给予不同浓度RS(40和2.5μmol·L^-1)分别处理,观察两组中细胞增殖和凋亡的变化及UCP2和SIRT3分子的表达;构建UCP2沉默细胞系,研究不同浓度RS对UCP2沉默前后细胞形态和线粒体膜电位的影响、以及SIRT3分子、线粒体外膜异位酶20(TOMM20)和线粒体合成相关蛋白(Drp1、Opa1和PGC1)的表达变化。结果RS能提高OGD/R细胞的存活率、抑制细胞凋亡、改变细胞形态、稳定细胞线粒体膜电位;增加OGD/R细胞中UCP2、SIRT3分子和TOMM20蛋白表达,并诱导Drp1和Opa1 mRNA的表达,抑制PGC1 mRNA的表达;沉默UCP2后能明显降低OGD/R细胞的存活率及TOMM20蛋白的表达,降低Drp1和Opa1 mRNA的表达,使PGC1 mRNA的表达增加。结论RS通过调控UCP2-SIRT3通路减轻CIR对神经元线粒体的损伤,发挥神经细胞保护作用。

Protective Effect of SGLT2 Inhibitor on D-Galactose-Induced Senescence in Mice and Its Mechanism

Objective: To observe the cerebral protective effect of dagliflozin, a sodium-glucose co-transport protein 2 (SGLT2) inhibitor, in aging mice and to explore its molecular mechanism. Methods: 1. 66 male C57BL/6 mice were divided into control group (13) and model group (53), and the model group was moulded by subcutaneous injection of D-galactose into the back of the neck, while the control group was treated with equal amount of saline for 8 weeks. The weight of each group of mice was observed and recorded every 7 days, and two groups of mice were randomly selected for frozen sections of brain tissue at the end of the modelling period to verify the aging model. 2. After the aging model was successfully established, the aging groups were divided into 5 groups: model group, dagliflozin-treated group (high and low dose), and dagliflozin + ex527-inhibited group (high and low dose). Fasting blood glucose was measured in each group every 2 weeks for 8 weeks. At the end of treatment, Morris water maze was performed at the end of the treatment. After execution of the mice, the organ indices of heart, brain, liver, kidney and spleen were measured;the levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in serum were determined. Results: After the successful establishment of the aging model, it was found that during the treatment phase of dagliflozin. 1) The organ indices of mice in the aging group were significantly lower than those of other groups, and no significant hypoglycemia was observed throughout the treatment process. 2) In the water maze test, mice in the aging group had a significantly longer latency in the plateau phase compared to the control and treatment groups, while the number of times the mice crossed the original plateau and the percentage of time spent exploring the original plateau quadrant were reduced after the plateau was removed. 3) The nerve cells in the aging mice were disorganized and the nuclei of the mice were deeply stained;the dagliflozin group improved the morphological changes in the brain of aging mice. 4) In addition, compared with the control mice, the serum MDA level was significantly increased and the antioxidant enzyme SOD activity was significantly decreased in the aging group, while compared with the aging group, dagliflozin significantly decreased the MDA level and increased the SOD activity. 5) The expression of SIRT1 and PGC-1α was significantly upregulated in the low and high doses of dagliflozin compared to the aging group. Conclusion: The present study suggests that dagliflozin can delay organ aging, improve the learning and memory ability of aging mice, and exert antioxidant effects, probably through upregulating the SIRT1/PGC-1α signaling pathway.

参苓白术散对NAFLD大鼠肝脏脂质代谢及SIRT1/UCP2通路的影响

目的观察参苓白术散对高脂饲料建立的非酒精性脂肪性肝病(NAFLD)大鼠脂质代谢及沉默信息调节因子1(SIRT1)/解偶联蛋白2(UCP2)通路的调控机制。方法取SD大鼠32只,随机分为4组,即正常组,模型组,参苓白术散高、低剂量组(30,10 g·kg^(-1)),每组8只。采用高脂饲料喂养大鼠16周建立NAFLD大鼠模型,给药组大鼠灌服参苓白术散,16周后取血和肝组织样本,全自动生化仪检测血清甘油三酯(TG)、总胆固醇(TC)含量;对肝组织进行油红O染色;实时荧光定量RT-PCR仪检测肝组织SIRT1、UCP2 mRNA表达水平;Western blotting检测肝组织SIRT1、UCP2蛋白表达水平。结果与正常组比较,模型组大鼠病理证实肝组织脂质蓄积严重,血清TG、TC含量明显升高(P<0.01),肝组织SIRT1 mRNA及蛋白表达均显著降低(P<0.05),UCP2 mRNA及蛋白表达显著升高(P<0.05,P<0.01)。与模型组比较,参苓白术散高、低剂量组肝组织脂质蓄积明显改善,血清TG、TC含量明显下降(P<0.05),肝组织SIRT1 mRNA和蛋白表达均显著上调(P<0.05,P<0.01),UCP2 mRNA和蛋白表达显著降低(P<0.01),其中,参苓白术散高剂量组较低剂量组效果好;但二者比较差异无统计学意义。结论参苓白术散能够改善高脂饮食诱导的NAFLD大鼠脂肪代谢紊乱、减轻肝脏脂质蓄积,其作用机制可能与肝细胞内SIRT1/UCP2通路的激活有关。

Novel nervous and multi-system regenerative therapeutic strategies for diabetes mellitus with mTOR

Throughout the globe,diabetes mellitus（DM） is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder.DM impacts multiple organs and affects all components of the central and peripheral nervous systems that can range from dementia to diabetic neuropathy.The mechanistic target of rapamycin（m TOR） is a promising agent for the development of novel regenerative strategies for the treatment of DM.m TOR and its related signaling pathways impact multiple metabolic parameters that include cellular metabolic homeostasis,insulin resistance,insulin secretion,stem cell proliferation and differentiation,pancreatic β-cell function,and programmed cell death with apoptosis and autophagy.m TOR is central element for the protein complexes m TOR Complex 1（m TORC1） and m TOR Complex 2（m TORC2） and is a critical component for a number of signaling pathways that involve phosphoinositide 3-kinase（PI 3-K）,protein kinase B（Akt）,AMP activated protein kinase（AMPK）,silent mating type information regulation 2 homolog 1（Saccharomyces cerevisiae）（SIRT1）,Wnt1 inducible signaling pathway protein 1（WISP1）,and growth factors.As a result,m TOR represents an exciting target to offer new clinical avenues for the treatment of DM and the complications of this disease.Future studies directed to elucidate the delicate balance m TOR holds over cellular metabolism and the impact of its broad signaling pathways should foster the translation of these targets into effective clinical regimens for DM.

A soy glycinin derived octapeptide protects against MCD diet induced non-alcoholic fatty liver disease in mice

Soy glycinin derived octapeptide(SGP8)is a peptide obtained from degradation of the soy glycinin,whose amino acid sequence is IAVPGEVA.To determine the effect of SGP8 on non-alcoholic fatty liver disease(NAFLD),steatosis Hep G2 cells were induced by 1 mmol/L free fatty acid(FFA)and C57 BL/6 J mice were fed with methionine-choline defi cient(MCD)diet for 3 weeks to establish NAFLD model.The results of oil red O staining and total cholesterol(TC)/triglyceride(TG)contents showed that SGP8 could signifi cantly reduce the lipid content of steatosis Hep G2 cells.In vivo,SGP8 lowered plasma alanine aminotransferase(ALT)and low density lipoprotein(LDL)content,normalized hepatic superoxide dismutase(SOD)and malondialdehyde(MDA)production,and reduced the severity of liver infl ammation.The results of Western blotting showed that SGP8 increased expression of Sirtuin-1(SIRT1)and phosphorylation level of AMP activated protein kinase(AMPK)in hepatocytes.Through activation of SIRT1/AMPK pathway,SGP8 downregulated the expression of sterol regulatory element binding protein 1 c(SREBP-1 c)and its target genes ACC and FAS expression levels,and increased the phosphorylation level of acetyl Co A carboxylase(ACC).Furthermore,SGP8 also upregulated the expression of transcription factor peroxisome proliferator activated receptorα(PPARα),which was regulated by SIRT1/AMPK pathway,and its target gene CPT1 level.In conclusion,SGP8 might improve NAFLD by activating the SIRT1/AMPK pathway.Our data suggest that SGP8 may act as a novel and potent therapeutic agent against NAFLD.

Hepatic SIRT6 deficit promotes liver tumorigenesis in the mice models

SIRT6 belongs to class III sirtuin family with NAD+-dependent histone deacetylase activities and controls multiple processes including aging,metabolism and inflammation.In recent years,increasing studies showed tumor suppressor role of SIRT6 in HCC development.We established a two-stage DEN followed CC14 induced liver carcinogenesis in the hepatic-specific SIRT6 HKO mice models and found that hepatic S1RT6 deficit significantly promotes liver injury and liver cancer through inhibition of the ERK1/2 pathway.SIRT6 was compensatory up-regulated in mice tumor tissues and human HCC cells and overexpressed SIRT6 inhibits tumor growth both in vitro and in vivo.Taken together,we provide a useful mouse model for delineating the molecular pathways involved in chronic liver diseases and primary liver cancer and suggest that SIRT6 can be a promising target for HCC therapies.