Di'ao Xinxuekang activates IRS-1/PI3K/Akt signal pathway to improve insulin resistance in nonalcoholic fatty hepatitis mice / 中国临床药理学与治疗学

AIM: To study the effect and mechanism of Di'ao Xinxuekang (DXXK) on insulin resistance in nonalcoholic steatohepatitis (NASH) mice. METHODS: C57BL/6J mice were randomly divided into normal group and model group. After 16 weeks of high-fat diet, the model group was randomly divided into model group and Pioglitazone group (6.0 mg · kg

Effect of miR-96-5p targeting IRS1 on apoptosis of PC12 cells induced by aluminum maltol / 中华劳动卫生职业病杂志

Objective: To investigate the effect and mechanism of miR-96-5p on apoptosis of PC12 cells induced by maltol aluminum. Methods: In January 2021, PC12 cells at logarithmic growth phase were divided into blank control group and low, medium and high dose group. Cells in each group were treated with 0, 100, 200 and 400 μmol/L maltol aluminum for 24 hours respectively. Cells were collected and cell apoptosis rates were detected by flow cytometry, miR-96-5p and insulin receptor substrate 1 (IRS1) mRNA expressions were detected by qRT-PCR, and the protein expression levels of cysteine protease 3 (Caspase3) 、activated cysteine protease 3 (Cleaved-caspase3) 、IRS1、phosphorylated protein kinase B (p-AKT) and phosphorylated glucose synthesis kinase 3β (p-GSK3β) were detected by western blotting. The target binding relationship between miR-96-5p and IRS1 was detected by double luciferase reporter gene experiment. The miR-96-5p inhibitor cells and negative control cells were constructed after transfecting PC12 cells with miR-96-5p inhibitor for 24 hours. The cells were divided into blank control group, negative control group, aluminum exposure group, aluminum exposure+negative control group, aluminum exposure+miR-96-5p inhibition group, and miR-96-5p inhibition group. After transfecting PC12 cells with miR-96-5p inhibition and IRS1 siRNA for 24 h, the cells were divided into aluminum exposure+miR-96-5p inhibition+negative control group and aluminum exposure+miR-96-5p inhibition+IRS1 inhibition group. The control group was cultured in complete culture medium, and cells in the aluminum exposure group were treated with 200 μmol/L maltol aluminum for 24 hours. Cells in each group were collected and the apoptosis rate, miR-96-5p and IRS1 mRNA expression levels, as well as protein expression levels of Caspase3, Cleaved-caspase3, IRS1, p-AKT, and p-GSK3β were measured. Results: After 24 hours of exposure, compared with blank control group and low-dose group, the apoptosis rates, relative expressions of Caspase3 and Cleaved-caspase3 proteins, and relative expressions of miR-96-5p in the medium and high-dose groups of PC12 cells were significantly increased, while the relative expression levels of IRS1 mRNA, IRS1, p-AKT and p-GSK3β proteins were significantly decreased (P<0.05). Targetscan prediction and double luciferase report experiment both proved that IRS1 was a direct target gene of miR-96-5p. In the transfection experiment, compared with the aluminum exposure group, the apoptosis rate, the relative expressions of Caspase3 and Cleaved-caspase3 proteins, the relative expression of miR-96-5p in the aluminum exposure+miR-96-5p inhibition group were significantly decreased, while the relative expression levels of IRS1 mRNA and IRS1, p-AKT and p-GSK3β proteins were significantly increased (P<0.05). In the IRS1 low expression experiment, compared with the aluminum exposure+miR-96-5p inhibition+negative control group, the apoptosis rate, the relative expressions of Caspase3 and Cleaved-caspase3 proteins in the aluminum exposure+miR-96-5p inhibition+IRS1 inhibition group were significantly increased, while the relative expression levels of IRS1 mRNA and IRS1, p-AKT and p-GSK3β proteins were significantly decreased (P<0.05) . Conclusion: The increased expression of miR-96-5p and the targeted inhibition of IRS1 may be one of the mechanisms of apoptosis of PC12 cells induced by maltol aluminum exposure.

Effects and mechanisms of total flavones of Abelmoschus manihot in improving insulin resistance and podocyte epithelial-mesenchymal transition in diabetic kidney disease based on IRS1/PI3K/Akt pathway / 中国中药杂志

This study aimed to explore the effects and mechanisms of total flavones of Abelmoschus manihot(TFA), the extracts from traditional Chinese medicine indicated for kidney diseases, on insulin resistance(IR) and podocyte epithelial-mesenchymal transition(EMT) in diabetic kidney disease(DKD), and further to reveal the scientific connotation. Thirty-two rats were randomly divided into a normal group, a model group, a TFA group, and a rosiglitazone(ROS) group. The modified DKD model was induced in rats by methods including high-fat diet feeding, unilateral nephrectomy, and streptozotocin(STZ) intraperitoneal injection. After modeling, the rats in the four groups were given double-distilled water, TFA suspension, and ROS suspension correspondingly by gavage every day. At the end of the 8th week of drug administration, all rats were sacrificed, and the samples of urine, blood, and kidney tissues were collected. The parameters and indicators related to IR and podocyte EMT in the DKD model rats were examined and observed, including the general condition, body weight(BW) and kidney weight(KW), the biochemical parameters and IR indicators, the protein expression levels of the key signaling molecules and structural molecules of slit diaphragm in the renal insulin receptor substrate(IRS) 1/phosphatidylinositol 3-kinase(PI3K)/serine-threonine kinase(Akt) pathway, foot process form and glomerular basement membrane(GBM) thickness, the expression of the marked molecules and structural molecules of slit diaphragm in podocyte EMT, and glomerular histomorphological characteristics. The results showed that for the DKD model rats, both TFA and ROS could improve the general condition, some biochemical parameters, renal appearance, and KW. The ameliorative effects of TFA and ROS were equivalent on BW, urinary albumin(UAlb)/urinary creatinine(UCr), serum creatinine(Scr), triglyceride(TG), and KW. Secondly, they could both improve IR indicators, and ROS was superior to TFA in improving fast insulin(FIN) and homeostasis model assessment of insulin resistance(HOMA-IR). Thirdly, they could both improve the protein expression levels of the key signaling molecules in the IRS1/PI3K/Akt pathway and glomerulosclerosis in varying degrees, and their ameliorative effects were similar. Finally, both could improve podocyte injury and EMT, and TFA was superior to ROS. In conclusion, this study suggested that podocyte EMT and glomerulosclerosis could be induced by IR and the decreased activation of the IRS1/PI3K/Akt pathway in the kidney in DKD. Similar to ROS, the effects of TFA in inhibiting podocyte EMT in DKD were related to inducing the activation of the IRS1/PI3K/Akt pathway and improving IR, which could be one of the scientific connotations of TFA against DKD. This study provides preliminary pharmacological evidence for the development and application of TFA in the field of diabetic complications.

Immunoexpression of PTEN, HER2/neu, and Ki-67 in endoscopic gastric carcinoma biopsies; their correlation with histological subtypes and one-year survival

Background: Gastric carcinoma is a major cause of cancer-related morbidity and mortality worldwide. Gastric neoplasms arise from genetic and epigenetic changes in various genes. Present study evaluates the immunoexpression of PTEN, HER2/neu, and Ki-67 in endoscopic gastric carcinoma biopsies and correlates the expression of these proteins with clinicopathological features. Material and Methods: Adequate endoscopic biopsies of 27 cases of gastric carcinoma were evaluated for World Health Organization (WHO) and Lauren's classification subtypes along with HER2/neu, PTEN, and Ki-67 immunoexpression. HER2/neu immunostaining was scored as proposed in the Trastuzumab for gastric cancer (ToGA) trial while PTEN staining and downregulation were assessed using an immunoreactive score. The cut-off for Ki-67 expression was taken as 90th percentile of the values in adjacent non-neoplastic tissue. All statistical analysis was done at 5% level of significance with SPSS v22 statistical software. Results: Tubular adenocarcinoma was the commonest WHO histological subtype and 56% of cases were of intestinal type as per Lauren's classification. 55.6% of cases showed a complete loss of PTEN expression in neoplastic tissue. 17 of the 19 cases with adjacent non-neoplastic tissue showed PTEN downregulation in neoplastic tissue. 81.5% of cases had a high Ki-67 index and HER2/neu overexpression was noted in 36% of cases. All the four cases who died had high Ki-67 proliferation indices; 3 patients had loss of PTEN expression and HER2/neu overexpression. Conclusion: We conclude that these immunomarkers can play important role in the behavior of gastric carcinomas and can be targeted for new therapies.

Effect of fucoxanthin on insulin resistance in obese mice induced by high fat diet / 中国中药杂志

The aim of this paper was to study the effect and mechanism of fucoxanthin on insulin resistance of obese mice induced by high-fat diet. Fifty C57 BL/6 J male mice were randomly divided into control group and high-fat diet group. The insulin resistance model was induced with high-fat diet for 12 weeks, and model mice were randomly divided into model group, fucoxanthin-0.2% group, fucoxanthin-0.4% group and metformin group. After dietary treatment for 6 weeks, the body weight and epididymal fat weight in each group were measured. Fasting blood glucose(FBG), fasting insulin(FINS), total cholesterol(TC), triglyceride(TG), low-density lipoprotein(LDL-C) and high-density lipoprotein(HDL-C) were measured, and insulin resistance index(HOMA-IR) was calcula-ted. The pathological morphology in liver was observed by hematoxylin eosin staining, and the expressions of some key proteins in insulin receptor substrate 1(IRS-1)/posphoinositide 3-kinase(PI3 K)/serine-threonine kinase(Akt) and peroxisome proliferators-activated receptor-γ(PPARγ)/sterol regulatory element binding protein-1(SREBP-1)/fatty acid synthetase(FAS) pathways in liver were detected by Western blot. According to the findings, compared with the model group, levels of body weight, epididymal fat weight, FBG, FINS, TC, TG, LDL-C and HOMA-IR, as well as protein expressions of PPARγ, SREBP-1 and FAS in liver were significantly reduced(P<0.05 or P<0.01), while level of HDL-C and protein expressions of p-IRS-1, IRS-1, PI3 K and p-Akt in liver were signi-ficantly increased after treatment with fucoxanthin(P<0.05 or P<0.01). And the pathological changes of liver tissue in fucoxanthin-treated mice were also improved obviously. The results showed that fucoxanthin could improve obesity, hyperglycemia and hyperlipidemia, and alleviate insulin resistance in obese mice, and its mechanism is possibly related to the regulation of IRS-1/PI3 K/Akt and PPARγ/SREBP-1/FAS pathways.

Effect of Baihutang Regulating IRS-1/PI3K/Akt Signal Pathway on Blood Glucose, Blood Lipid Metabolism and Vascular Remodeling in Type 2 Diabetic Rats / 中国实验方剂学杂志

Objective:To study the effect of Baihutang on blood glucose， blood lipid metabolism and vascular remodeling in type 2 diabetic rats and its regulation on insulin receptor substrate-1（IRS-1）/ phosphatidylinositol-3 kinase（PI3K）/ protein kinase B（Akt） signal pathway. Method:The 90 rats were randomly divided into normal group， model group， Baihutang low， middle and high dose groups and metformin group， with 15 rats in each group. Except for normal group， the other rats were injected intraperitoneally with streptozotocin to establish the model of type 2 diabetes. The rats in the low， middle and high dose groups were given Baihutang formula granules of 5， 10， 20 g·kg-1 respectively according to their body weight. The positive control group was given metformin （100 mg·kg-1） by intragastric administration， while those in the control group and model group were given the same amount of normal saline once a day for 12 weeks. The levels of fasting blood glucose， glycosylated hemoglobin， serum tumor necrosis factor-α（TNF-α）， interleukin-6（IL-6）， interleukin-1 β（IL-1β）， total cholesterol（TC）， triglyceride（TG） and low-density lipoprotein cholesterol（LDL-C） were measured after administration. The levels of sterol regulatory element binding protein 1C （SREBP1C）， acetyl CoA carboxylase （ACC）， fatty acid synthase gene （FASN） and carnitine palmitoyl transferase 1A （CPT1A）， acylcoa oxidase 1（ACOX1）， recombinant human acylcoa dehydrogenase （ACADM） mRNA in liver of rats were detected by Real-time fluorescence quantitative polymerase chain reaction（Real-time PCR）， Western blot was used to detect the protein levels of IRS-1， PI3K and Akt in liver of rats. Hematoxylin-eosin（HE） staining was used for histopathological examination of rat thoracic aortic vessels. The migration ability of vascular smooth muscle cells in rat thoracic aorta was detected by scratch test. Result:Compared with the normal group， the fasting blood glucose， glycosylated hemoglobin， serum TNF-α， IL-6，IL-1β， TC，TG and LDL-C levels， liver lipid synthesis gene mRNA level and vascular smooth muscle cell migration ability of thoracic aorta in model group were significantly higher than those in normal group （P<0.05）， while fatty acid oxidation gene mRNA level and IRS-1，PI3K，Akt protein level in liver were significantly decreased in model group （P<0.05）. The vascular wall thickness of thoracic aorta increased significantly in rats （P<0.05）. Compared with model group， the levels of fasting blood glucose， glycosylated hemoglobin， serum TNF-α，IL-6， IL-1β， TC， TG and LDL-C， the level of lipid synthesis gene mRNA in liver and the migration ability of vascular smooth muscle cells in thoracic aorta of rats in all Baihutang groups were significantly lower than those in model group （P<0.05）. The mRNA level of fatty acid oxidation gene and the protein levels of IRS-1， PI3K and Akt in liver were significantly increased（P<0.05）， and the histopathology of thoracic aorta was significantly improved and the vascular wall thickness decreased significantly（P<0.05）. Conclusion:Baihutang can reduce the levels of blood glucose， blood lipid and serum inflammatory factors in type 2 diabetic rats， regulate the expression of genes related to lipid metabolism in liver， and improve the histopathology and vascular remodeling of thoracic aorta. The mechanism may be related to the regulation of IRS-1/PI3K/Akt signal pathway.

Bitter gourd extract improves glucose homeostasis and lipid profile via enhancing insulin signaling in the liver and skeletal muscles of diabetic rats

Objective: To investigate the modulatory effects of bitter gourd extract on the insulin signaling pathway in the liver and skeletal muscle tissues of diabetic rats. Methods: The ethanolic extract of bitter gourd was prepared and its contents of total polyphenols and flavonoids were assayed. A neonatal streptozotocin-induced diabetic rat model was established and the diabetic rats were assigned into different groups and were treated with different doses of bitter gourd extract (100, 200, 400, or 600 mg/kg) or with glibenclamide (0.1 mg/kg) for 30 d. Fasting blood glucose, insulin, and lipid profile were evaluated and the insulin signaling pathway in the liver and skeletal muscle of rats was investigated. The correlations between homeostasis model assessment (HOMA) and the components of insulin signaling pathway were also evaluated. Results: Different doses of bitter gourd extract significantly ameliorated fasting blood glucose level and HOMA index for insulin resistance. Moreover, bitter gourd extract increased serum insulin and improved disrupted serum lipid profile. The levels of insulin receptor substrate-1 (IRS-1), p-insulin receptor β (p-IR-β), protein kinase C (PKC), GLUT2, and GLUT4 were improved by treatment with bitter gourd extract. The best results were obtained with 400 mg/kg dose of the extract, the effect of which was equivalent to that of glibenclamide. HOMA in the bitter gourd treated rats was negatively correlated with p-IR-β, IRS-1 and PKC in hepatic and skeletal muscle. HOMA was also negatively correlated with skeletal muscle GLUT4. Conclusions: Bitter gourd extract improves glucose homeostasis and lipid profile in diabetic rats via enhancement of insulin secretion and sensitivity. Therefore, bitter gourd can be used as a potential pharmacological agent for the treatment of type 2 diabetes mellitus.

Prevalence of Insulin Receptor Substrate-1 Gene (G972R) Polymorphism, Insulin Resistance, and Determination of β-Cell Function among overweight and obese persons with Type 2 Diabetes Mellitus / Journal of the ASEAN Federation of Endocrine Societies

Background@#Type 2 diabetes mellitus (T2DM) is the most common metabolic disorder and its pathogenesis is characterized by a combination of peripheral insulin resistance and impaired insulin secretory capacity of pancreatic β cell. Genetic predisposition interacts with environmental factors including diet, physical activity, and age leading to the development of diabetes.@*Objective@#To determine the proportion of overweight and obese persons with type 2 diabetes and to compare the fasting blood sugar, fasting serum insulin, insulin resistance and β-cell function in G972R carrier and non-carrier overweight and obese persons with type 2 diabetes.@*Methodology@#One hundred overweight and obese patients with T2DM were recruited from persons with diabetes attending the Diabetes Outpatient Department of Yangon General Hospital. History taking and physical examination were done and blood samples were collected. Plasma glucose level was determined by the glucose oxidase method and fasting serum insulin was measured by enzyme linked immunoassay (ELISA) kit method. Polymerase chain reaction and Restriction Fragment Length Polymorphism were done for genetic polymorphism.@*Results@#Among 100 overweight and obese subjects with T2DM, 81 patients were of homozygous (G/G) genotype, 18 patients were of heterozygous (G/A) and only one patient of homozygous (A/A) genotype. There was no statistically significant difference in the proportion of genotypes between overweight and obese subjects with T2DM.There was no significant difference in fasting blood sugar (FBS), fasting serum insulin, HOMA-IR, β-cell function, lipid parameters between IRS-1 (G972R) carriers and non-carriers. There is significant negative correlation between insulin resistance and TG level (r2=0.0529, p=0.01).@*Conclusion@#It was concluded that IRS-1 G972R polymorphism was not important in insulin resistance, β-cell function and lipid parameters in overweight and obese T2DM. There could be a number of candidate genes in the pathophysiology of diabetes mellitus, genetic sequencing of IRS-1 and other genes in the insulin signaling pathway, and finding out the alteration in their genetic patterns would provide clues for the association of the site-specific polymorphisms of these genes with insulin resistance in T2DM.

Effects of Zuogui Jiangtang Jieyu Formulation on insulin resistance in hipppocampus of rats with diabetes-related depression / 中草药

Objective: To investigate the function of Zuogui Jiangtang Jieyu Formulation on hippocampal insulin resistance in rats with diabetes-related depression. Methods: The rat model of diabetes-related depression was established and randomly divided into four groups, including model group, positive drug group (metformin 0.18 g/kg + fluoxetine 1.8 mg/kg), high (20.53 g/kg) and low (10.26 g/kg) doses of Zuogui Jiangtang Jieyu Formulation groups. After 28 d of gavage, fasting blood glucose and peripheral insulin resistance were measured by blood glucose meter and ELISA. The depression-like behaviors of rats were tested by open field experiment and forced swimming test. The expression of p-IR and p-IRS-1 in hippocampus of rats were detected by immunofluorescence and Western blotting, while the levels of p-PI3K and p-Akt were detected by Western blotting. Results: Compared with the normal group, the blood glucose of rats in model group were significantly increased, which accompanied by obvious peripheral insulin resistance. The number of activities in open field experiment was significantly reduced in model group, and the immobility time in forced swimming experiment was significantly prolonged. In addition, it was showed that the levels of p-IR, p-IRS-1, p-PI3K and p-Akt in the brain of model rats were all significantly decreased. Compared with the model group, the blood glucose and insulin levels were significantly decreased in high-dose of Zuogui Jiangtang Jieyu Formulation group. Furthermore, the depression-like behaviors manifested in open field experiment and forced swimming experiment were improves by high dose of Zuogui Jiangtang Jieyu Formulation. More importantly, the expression of p-IR, p-IRS-1, p-PI3K and p-Akt in hippocampus was significantly increased in high dose of Zuogui Jiangtang Jieyu Formulation group compared with model group. Conclusion: Zuogui Jiangtang Jieyu Formulation can effectively regulate the insulin signaling pathway in hippocampus of rats with diabetes-related depression, and then improve the insulin resistance in the brain of model rats.

Understanding Behavioural Temperament of Phlebotomus argentipes Under the Influence of DDT-IRS Versus SP-IRS for Scoping New Approaches for Maximum Control Over the VL-Vector Population in Bihar

Background:After the decades of Dichlorodiphenyltrichloroethane (DDT) use, Phlebotomus argentipesreportedly developed resistance against it affecting every aspect of vector control at grass-root level. Although DDT based Indoor Residual Spray (IRS) has been replaced with Alphacypermethrine-a Synthetic Pyrethroid (SP) based insecticide, since 2016 butits successful implementation at the Visceral Leishmaniasis (VL) endemic regime of Bihar doesn’t cause much effect upon VL vector density. Furthermore, the outcomes of existing operational research works, it Original ResearchArticle had been observed that VL vectors are continuously changing its behavior under the pressure of insecticides. Methods: For validating the hypothesis, present study has been carried out at Vaishali and Patna being highly and semi-endemic sites respectively for quantifying the oriental behavior among VL vectors persuaded by the IRS and enforce them to remain alive and get trapped in light trap even after changed chemical composition of IRS i.e., SP-IRS from routine DDT-IRS. Results:Following results, a significant reduction in sand fly density (i.e., 33.09% and 29.16%) was observed for outdoor and indoor caught sand flies, collected with light trap and aspirator respectively. Significant higher no. of sand fly collection in terms of per light traps per night was recorded from the outdoor sites than thosefrom indoor habitat for each village of Vaishali and Saran district of Bihar. Higher no. of male sand flies than to that of female ones were collected from outdoor sites and only unfed female sand flies (i.e., 100%) were caught following SP-IRS from each study villages of Vaishali and Saran districts of Bihar.Conclusions:The results of higher no. of sand flies collection from the outdoor sites as compared with the indoor habitat validate the hypothesis of gradual shifting of habitat of VL vectors from endophilic to exophilic which is undoubtedly followed due to the fact of developed resistance among them against chemical constituent of IRS. Results provide very useful information about the sand fly dynamics under the impact of IRS and accordingly, advocates the combined approach of IRS along with insecticidal fogging together at a same time that could be an effective dividend for maximum VL vector control along for negotiating VL cases at par for longer duration during the maintenance phase at the VL foci.

Recurrent vaginal discharge: an unusual presentation of embryonal rhabdomyosarcoma of uterine cervix in an adolescent girl

Embryonal rhabdomyosarcoma (ERMS) is a rare tumor of the female genital tract. It tends to occur during childhood in the vagina and rarely it can arise in the uterine cervix, with a peak incidence in the second decade. We report a case of 15 year old adolescent girl who presented with recurrent vaginal discharge not responding to medical treatment. Examination under anesthesia showed friable growth arising from the cervix. Histopathological examination revealed embryonal rhabdomyosarcoma (botyroid variant) of the cervix. Patient underwent local excision of growth followed by IRS-4 protocol based chemotherapy and now patient is under follow up at our side and pediatric oncology and doing well. Young girls presenting with recurrent vaginal discharge not responding to medical treatment must undergo proper clinical examination and EUA and any suspicious lesions should be examined so as to avoid missing rare but aggressive etiology like rhabdomyosarcoma. Due to the young age of affected patients, embryonal rhabdomyosarcoma (sarcoma botyroides) poses a management challenge as the preservation of hormonal, sexual and reproductive function is essential. Awareness of such as uncommon lesion and its clinical implications is important for the counseling and management of the patient.

Knowledge, attitude and practices regarding malaria among residents of rural Mangalore, India

Background: Malaria is one of the most prevalent parasitic diseases worldwide and India has fourth highest number of malaria cases and deaths in the world. Prevention of the disease through better knowledge and awareness is the appropriate way to keep the disease away and remain healthy. Thus, the present study was aimed to assess the knowledge, attitude and practices regarding malaria among residents of Mangalore.Methods: Community based cross sectional study was conducted among residents in Mangalore. The data was collected by using pre-tested semi-structured questionnaire which include socio-demographic data, basic knowledge about malaria, transmission and preventive measures and health seeking behaviour regarding malaria through interview method.Results: Almost 98.4% respondents heard of malaria disease and 96% respondents had knowledge that malaria is caused by mosquito bite. Even, majority (72%) of respondents knew that malaria can be fatal. Regarding the symptoms of malaria, 52.4% respondents mentioned fever with chills and 11.6% respondents don’t know about malarial symptoms.Conclusions: Majority of the respondents were familiar with the malaria symptoms, mode of transmission and vector control measures. They had good knowledge of malaria disease and good practices of malaria control measures.

Study on Hypoglycemic Effect and Mechanism of Zicui Yin on Type Ⅱ Diabetic Rats / 中国药房

OBJECTIVE： To study the hypoglycemic effect and mechanism of Zicui yin on type Ⅱ diabetic rats， and to provide theoretic basis for clinical application. METHODS： Eighty male rats were fed with high fat/sugar diet for 4 weeks， and then given intraperitoneal injected with streptozotocin （35 mg/kg） to induce type 2 diabetic model. Other 10 rats were included in normal group. Model rats were randomly divided into metformin group （positive control， 0.2 g/kg）， model group （constant volume of distilled water）， Zicui yin high-dose， medium-dose， low-dose groups （14.0， 7.0， 3.5 g/kg）， with 10 rats in each group. After 2 weeks of continuous intragastic administration， the fasting blood glucose of rats in each group was measured by automatic blood glucose meter. The serum insulin level was determined by ELISA. mRNA expression of JNK， Akt and IRS-1 were detected by RT-PCR； The phosphorylation of JNK， Akt and IRS-1 proteins in the pancreatic tissue of rats in each group was detected by Western blot method. RESULTS： Compared with normal group， the fasting blood glucose， mRNA expression of JNK， The phosphorylation of JNK and IRS-1 proteins in the pancreatic tissue of the model group were significantly increased （P＜0.05 or P＜0.01）， while the serum insulin content， mRNA expression of Akt and IRS-1， the phosphorylation of Akt protein were significantly decreased （P＜0.01）. Compared with model group， the fasting blood glucose of rats in metformin group and Zicui yin high-dose and middle-dose groups decreased significantly （P＜0.05）， the serum insulin content of rats in both metformin group and Zicui yin high-dose group increased significantly （P＜0.01）， and mRNA expression of JNK in pancreatic tissue of rats in metformin group and Zicui yin groups decreased significantly （P＜0.01）， while mRNA expression of Akt and IRS-1 increased significantly （P＜0.01）. The phosphorylation of JNK and IRS-1 proteins in metformin group and Zicui yin high-dose group decreased significantly （P＜0.01）， while the phosphorylation of        Akt protein were increased significantly （P＜0.01）. CONCLUSIONS： Zicui yin can significantly reduce blood glucose level， the mechanism of which may be related to decreasing the phosphorylation of JNK and IRS-1 proteins and increasing the phosphorylation of Akt proteins in pancreatic islets.

Telmisartan increases hepatic glucose production via protein kinase C ζ-dependent insulin receptor substrate-1 phosphorylation in HepG2 cells and mouse liver / 영남의대학술지

BACKGROUND: Dysregulation of hepatic glucose production (HGP) contributes to the development of type 2 diabetes mellitus. Telmisartan, an angiotensin II type 1 receptor blocker (ARB), has various ancillary effects in addition to common blood pressure-lowering effects. The effects and mechanism of telmisartan on HGP have not been fully elucidated and, therefore, we investigated these phenomena in hyperglycemic HepG2 cells and high-fat diet (HFD)-fed mice.METHODS: Glucose production and glucose uptake were measured in HepG2 cells. Expression levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase α (G6Pase-α), and phosphorylation levels of insulin receptor substrate-1 (IRS-1) and protein kinase C ζ (PKCζ) were assessed by western blot analysis. Animal studies were performed using HFD-fed mice.RESULTS: Telmisartan dose-dependently increased HGP, and PEPCK expression was minimally increased at a 40 μM concentration without a change in G6Pase-α expression. In contrast, telmisartan increased phosphorylation of IRS-1 at Ser302 (p-IRS-1-Ser302) and decreased p-IRS-1-Tyr632 dose-dependently. Telmisartan dose-dependently increased p-PKCζ-Thr410 which is known to reduce insulin action by inducing IRS-1 serine phosphorylation. Ectopic expression of dominant-negative PKCζ significantly attenuated telmisartan-induced HGP and p-IRS-1-Ser302 and -inhibited p-IRS-1-Tyr632. Among ARBs, including losartan and fimasartan, only telmisartan changed IRS-1 phosphorylation and pretreatment with GW9662, a specific and irreversible peroxisome proliferator-activated receptor γ (PPARγ) antagonist, did not alter this effect. Finally, in the livers from HFD-fed mice, telmisartan increased p-IRS-1-Ser302 and decreased p-IRS-1-Tyr632, which was accompanied by an increase in p-PKCζ-Thr410.CONCLUSION: These results suggest that telmisartan increases HGP by inducing p-PKCζ-Thr410 that increases p-IRS-1-Ser302 and decreases p-IRS-1-Tyr632 in a PPARγ-independent manner.

Palmitic acid-induced lipotoxicity promotes a novel interplay between Akt-mTOR, IRS-1, and FFAR1 signaling in pancreatic ß-cells

BACKGROUND: Free fatty acid receptor 1 (FFAR1) is G-protein coupled receptor predominantly expressed in pancreatic ß-cells that is activated by a variety of free fatty acids (FFAs). Once activated, it promotes glucose-stimulated insulin secretion (GSIS). However, increased levels of FFAs lead to lipotoxicity, inducing loss of ß-cell function. FFAR1 plays a key role in the development of type 2 diabetes (T2D), and previous studies have indicated the importance of developing anti-diabetic therapies against FFAR1, although its role in the regulation of ß-cell function remains unclear. The present study investigated the role of FFAR1 under lipotoxic conditions using palmitic acid (PA). The rat insulinoma 1 clone 832/13 (INS-1 832/13) cell line was used as a model as it physiologically resembles native pancreatic ß-cells. Key players of the insulin signaling pathway, such as mTOR, Akt, IRS-1, and the insulin receptor (INSR1ß), were selected as candidates to be analyzed under lipotoxic conditions. RESULTS: We revealed that PA-induced lipotoxicity affected GSIS in INS-1 cells and negatively modulated the activity of both IRS-1 and Akt. Reduced phosphorylation of both IRS-1 S636/639 and Akt S473 was observed, in addition to decreased expression of both INSR1ß and FFAR1. Moreover, transient knockdown of FFAR1 led to a reduction in IRS-1 mRNA expression and an increase in INSR1ß; mRNA. Finally, PA affected localization of FFAR1 from the cytoplasm to the perinucleus. CONCLUSIONS: In conclusion, our study suggests a novel regulatory involvement of FFAR1 in crosstalk with mTOR-Akt and IRS-1 signaling in ß-cells under lipotoxic conditions.

The effect of noise exposure on insulin sensitivity in mice may be mediated by the JNK/IRS1 pathway

BACKGROUND@#Epidemiological studies have suggested that noise exposure may increase the risk of type 2 diabetes mellitus (T2DM), and experimental studies have demonstrated that noise exposure can induce insulin resistance in rodents. The aim of the present study was to explore noise-induced processes underlying impaired insulin sensitivity in mice.@*METHODS@#Male ICR mice were randomly divided into four groups: a control group without noise exposure and three noise groups exposed to white noise at a 95-dB sound pressure level for 4 h/day for 1, 10, or 20 days (N1D, N10D, and N20D, respectively). Systemic insulin sensitivity was evaluated at 1 day, 1 week, and 1 month post-noise exposure (1DPN, 1WPN, and 1MPN) via insulin tolerance tests (ITTs). Several insulin-related processes, including the phosphorylation of Akt, IRS1, and JNK in the animals' skeletal muscles, were examined using standard immunoblots. Biomarkers of inflammation (circulating levels of TNF-α and IL-6) and oxidative stress (SOD and CAT activities and MDA levels in skeletal muscles) were measured via chemical analyses.@*RESULTS@#The data obtained in this study showed the following: (1) The impairment of systemic insulin sensitivity was transient in the N1D group but prolonged in the N10D and N20D groups. (2) Noise exposure led to enhanced JNK phosphorylation and IRS1 serine phosphorylation as well as reduced Akt phosphorylation in skeletal muscles in response to exogenous insulin stimulation. (3) Plasma levels of TNF-α and IL-6, CAT activity, and MDA concentrations in skeletal muscles were elevated after 20 days of noise exposure.@*CONCLUSIONS@#Impaired insulin sensitivity in noise-exposed mice might be mediated by an enhancement of the JNK/IRS1 pathway. Inflammation and oxidative stress might contribute to insulin resistance after chronic noise exposure.

Effect and mechanism of Vaspin on insulin resistance of 3T3-L1 adipocytes induced by palmitic acid / 中华临床营养杂志

Objective To investigate the effects of vaspin on insulin resistants of 3T3-L1 adipocyte through the insulin receptor substrates (IRS) /phosphatidylinositol 3-kinase (PI3K) /protein kinase B (Akt) /glucose transporter (Glut) signaling pathway.Methods 3T3-L1 cells cultured by palmitic acid (PA) were used to establish insulin resistance models,which were divided into PA group,PA + 100 ng/ml vaspin group,PA+200 ng/ml vaspin group,PA+400 ng/ml vaspin group and PA+400 ng/ml vaspin+wortmannin (PI3K inhibitor) group.Glucose uptake and consumption were assessed by 2-deoxy H3-D-glucose incorporation and glucose oxidase-peroxidase respectively.IRS/PI3K/Akt/Glut signaling pathway was evaluated using reverse transcription polymerase chain reaction and Western blot analysis.Results Compared with PA group,glucose uptake and consumption increased gradually with the increasing of vaspin concentration in other groups (P ＜ 0.05).mRNA levels of IRS-1,Akt and Glut 4 increased gradually as vaspin concentration increasing (P＜0.05),and the ratios of p-IRS-1 to IRS-1,p-Akt to Akt and Glut 4 protein level also showed the same trends (P＜0.05).However,glucose uptake and consumption in PA+400 ng/ml vaspin+wortmannin group were less than that of PA +400 ng/ml vaspin group (P＜0.05).PA+400 ng/ml vaspin+wortmannin group showed lower mRNA and protein phosphorylation levels of IRS-1,Akt and Glut 4 (P＜0.05),and that the ratios of p-IRS-1 to IRS-1,p-Akt to Akt and Glut 4 protein levels decreased (P＜0.05).Conclusions Vaspin can improve the insulin sensitivity of 3T3-L1 adipocyte by activating IRS/PI3K/Akt/Glut signaling pathway.

Effects of Ji Tang Zhi on glucose metabolism and related protein expression in insulin resistance HepG 2 cell line / 药物评价研究

Objective To evaluate the effect of Ji Tang Zhi on glucose metabolism in insulin resistance (IR) HepG 2 cell line,and to explore the related mechanism.Methods The HepG2 cells were incubated in culture medium addition of 10-7 mol/L insulin for 24 h to establish the IR cell model.Effect of Ji Tang Zhi on rate of glucose absorption in HepG2 cell was detected by the method of glucose oxidase-peroxidase (GOD-POD).We performed an MTT assay to determine cytotoxicity effects of Ji Tang Zhi on HepG2 cell line.The expression of p-IRS-1 Ser307,PI3K and GLUT-4 were detected by Western blotting.Results Incubated with 10-7 mol/L insulin for 24 h,the insulin resistance cell model had been built.Compared with model group,the rate of glucose absorption of cell treated with JTZ (30 ～ 120 μg/mL) was significantly improved.According to model cells,the expression of GLUT-4 and PI3K decreased significantly compared to control cells.While the expression of p-IRS-1 Ser 307 was inhibited and GLUT-4 and PI3K expression were increased in IR cells after treated with JTZ (30 ～ 120 μtg/mL).Conclusion JTZ exert beneficial effects on hyperglycosemia in IR cell line possibly through regulating the levels of GLUT-4,p-IRS-1 Ser307 and PI3K in HepG2 cell.

Effects of pioglitazone on E2 secretion in PCOS ovarian granulosa cells / 西安交通大学学报(医学版)

Objective To observe the effects of pioglitazone on secretion of E2 and expressions of P450 aromatase (P450arom), insulin-receptor substrate-1 (IRS-1), and insulin-receptor substrate-2 (IRS-2) mRNA in polycystic ovary syndrome (PCOS) ovarian granulosa cells.Methods In this study, granulosa cells that were fertilization-embryo transferred from 27 PCOS patients were primary cultured in vitro with different concentrations of pioglitazone (0, 10, 102, 103 and 104nmol/L) (Group A), different concentrations of pioglitazone+FSH (50ng/L, Group B) and different concentrations of pioglitazone+insulin-like growth factor I (IGF-I, 50ng/L, Group C).Estradiol concentrations in the culture supernatant were detected by radioimmunoassay;P450arom, IRS-1 and IRS-2 mRNA expressions on granulosa cells were detected by Real-time PCR.Results The levels of E2 secreted by granulosa cells and the expression of P450arom mRNA on granulosa cells of PCOS for 48 hours were different among Groups A, B and C (P<0.05).With increase in pioglitazone concentration, the level of E2 and the expression of P450arom mRNA declined, some of which correlated negatively with the concentration of pioglitazone.Among these groups, the level of E2 secretion and the expression of P450arom mRNA were higher in Group C than in Group B (P<0.01) and Group A (P<0.01) at the same concentration of pioglitazone.The level of E2 secretion and the expression of P450arom mRNA were higher in Group B than in Group A (P<0.05) at the same concentration of pioglitazone.The expressions of IRS-1 and IRS-2 mRNA on granulosa cells of PCOS under pioglitazone stimulation for 48 hour were different among the groups of different pioglitazone concentrations (P<0.05).With increase inpioglitazone concentration, the expression of IRS-1 mRNA on granulosa cells of PCOS was decreased, but the expression of IRS-2 mRNA on granulosa cells of PCOS was increased.Conclusion Pioglitazone may decrease estrogen production by inhibiting p450 aromatase and adjusting the expressions of IRS-1 and IRS-2 on granulosa cells of PCOS to play a role in ovulation induction and ameliorate insulin resistance in ovary of PCOS.Pioglitazone can inhibit IGF-I and FSH in inducing E2 secretion by ovarian granulosa cells.

Effect of water extract from Jiangtang Decoction on PI3K/Akt signal pathway of skeletal muscle metabolism in KK-Ay diabetic mice / 药物评价研究

Objective To explore the effects of water extract from Jiangtang Decoction (WEJTD) on PI3K/Akt signal pathway of skeletal muscle metabolism in KK-Ay diabetic mice.Methods Totally 50 KK-Ay mice were randomly divided into five groups:model group,metformin (positive drug,250 mg/kg) group,WEJTD low,medium,and high dose (2,4,and 8 g/kg) group,with 10 C57BL/6J mice as normal group.The relative drugs were ig administered once a day for 12 weeks,and mice in control group and model group were perfused with distilled water of equal volume.After 12 weeks' oral administration,mice were executed to separate serum,serum insulin level was detected by ELISA kit method;RNA was extracted from muscle tissue by Trizol,and real-time PCR were used to detect the level of PI3K,Akt,GLUT-4,GSK-3β,GS and IRS-1 mRNA.Results WEJTD can down-regulate concentration of insulin in serum and GSK-3β mRNA in skeletal muscle (P ＜ 0.05 and 0.001),and down-regulate mRNA of PI3K,Akt,IRS-1,GLUT-4,and GS in skeletal muscle (P ＜ 0.05,0.01,and 0.001).Conclusion WEJTD decreased glycogen deposition and stimulated glucose transport in skeletal muscle through upregulation of PI3K/Akt signaling pathway.