Mulberry leaf flavonoids activate BAT and induce browning of WAT to improve type 2 diabetes via regulating the AMPK/SIRT1/PGC-1α signaling pathway / 中国天然药物

Mulberry (Morus alba L.) leaf is a well-established traditional Chinese botanical and culinary resource. It has found widespread application in the management of diabetes. The bioactive constituents of mulberry leaf, specifically mulberry leaf flavonoids (MLFs), exhibit pronounced potential in the amelioration of type 2 diabetes (T2D). This potential is attributed to their ability to safeguard pancreatic β cells, enhance insulin resistance, and inhibit α-glucosidase activity. Our antecedent research findings underscore the substantial therapeutic efficacy of MLFs in treating T2D. However, the precise mechanistic underpinnings of MLF's anti-T2D effects remain the subject of inquiry. Activation of brown/beige adipocytes is a novel and promising strategy for T2D treatment. In the present study, our primary objective was to elucidate the impact of MLFs on adipose tissue browning in db/db mice and 3T3-L1 cells and elucidate its underlying mechanism. The results manifested that MLFs reduced body weight and food intake, alleviated hepatic steatosis, improved insulin sensitivity, and increased lipolysis and thermogenesis in db/db mice. Moreover, MLFs activated brown adipose tissue (BAT) and induced the browning of inguinal white adipose tissue (IWAT) and 3T3-L1 adipocytes by increasing the expressions of brown adipocyte marker genes and proteins such as uncoupling protein 1 (UCP1) and beige adipocyte marker genes such as transmembrane protein 26 (Tmem26), thereby promoting mitochondrial biogenesis. Mechanistically, MLFs facilitated the activation of BAT and the induction of WAT browning to ameliorate T2D primarily through the activation of AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) signaling pathway. These findings highlight the unique capacity of MLF to counteract T2D by enhancing BAT activation and inducing browning of IWAT, thereby ameliorating glucose and lipid metabolism disorders. As such, MLFs emerge as a prospective and innovative browning agent for the treatment of T2D.

Knockdown of PGC1α suppresses dysplastic oral keratinocytes proliferation through reprogramming energy metabolism / 国际口腔科学杂志·英文版

Oral potentially malignant disorders (OPMDs) are precursors of oral squamous cell carcinoma (OSCC). Deregulated cellular energy metabolism is a critical hallmark of cancer cells. Peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC1α) plays vital role in mitochondrial energy metabolism. However, the molecular mechanism of PGC1α on OPMDs progression is less unclear. Therefore, we investigated the effects of knockdown PGC1α on human dysplastic oral keratinocytes (DOKs) comprehensively, including cell proliferation, cell cycle, apoptosis, xenograft tumor, mitochondrial DNA (mtDNA), mitochondrial electron transport chain complexes (ETC), reactive oxygen species (ROS), oxygen consumption rate (OCR), extracellular acidification rate (ECAR), and glucose uptake. We found that knockdown PGC1α significantly inhibited the proliferation of DOKs in vitro and tumor growth in vivo, induced S-phase arrest, and suppressed PI3K/Akt signaling pathway without affecting cell apoptosis. Mechanistically, downregulated of PGC1α decreased mtDNA, ETC, and OCR, while enhancing ROS, glucose uptake, ECAR, and glycolysis by regulating lactate dehydrogenase A (LDHA). Moreover, SR18292 (an inhibitor of PGC1α) induced oxidative phosphorylation dysfunction of DOKs and declined DOK xenograft tumor progression. Thus, our work suggests that PGC1α plays a crucial role in cell proliferation by reprograming energy metabolism and interfering with energy metabolism, acting as a potential therapeutic target for OPMDs.

PGC1α plays a pivotal role in renal fibrosis via regulation of fatty acid metabolism in renal tissue / 中南大学学报(医学版)

Renal fibrosis is a common and irreversible pathological feature of end-stage renal disease caused by multiple etiologies. The role of inflammation in renal fibrosis tissue has been generally accepted. The latest view is that fatty acid metabolism disorder contributes to renal fibrosis. peroxisome proliferator activated receptor-gamma coactivator 1α (PGC1α) plays a key role in fatty acid metabolism, regulating fatty acid uptake and oxidized protein synthesis, preventing the accumulation of lipid in the cytoplasm, and maintaining a dynamic balanced state of intracellular lipid. In multiple animal models of renal fibrosis caused by acute or chronic kidney disease, or even age-related kidney disease, almost all of the kidney specimens show the down-regulation of PGC1α. Upregulation of PGC1α can reduce the degree of renal fibrosis in animal models, and PGC1α knockout animals exhibit severe renal fibrosis. Studies have demonstrated that AMP-activated protein kinase (AMPK), MAPK, Notch, tumor necrosis factor-like weak inducer of apoptosis (TWEAK), epidermal growth factor receptor (EGFR), non-coding RNA (ncRNAs), liver kinase B1 (LKB1), hairy and enhancer of split 1 (Hes1), and other pathways regulate the expression of PGC1α and affect fatty acid metabolism. But some of these pathways interact with each other, and the effect of the integrated pathway on renal fibrosis is not clear.

Mechanism of Zexie Decoction in improvement of nonalcoholic fatty liver disease based on LKB1/AMPK/PGC-1α pathway / 中国中药杂志

The present study investigated the pharmaceutical effect and underlying mechanism of Zexie Decoction(ZXD) on nonalcoholic fatty liver disease(NAFLD) in vitro and in vivo via the LKB1/AMPK/PGC-1α pathway based on palmitic acid(PA)-induced lipid accumulation model and high-fat diet(HFD)-induced NAFLD model in mice. As revealed by the MTT assay, ZXD had no effect on HepG2 activity, but dose-dependently down-regulated alanine aminotransferase(ALT) and aspartate aminotransferase(AST) in the liver cell medium induced by PA, and decreased the plasma levels of ALT and AST, and total cholesterol(TC) and triglyceride(TG) levels in the liver. Nile red staining showed PA-induced intracellular lipid accumulation, significantly increased lipid accumulation of hepatocytes induced by PA, suggesting that the lipid accumulation model in vitro was properly induced. ZXD could effectively improve the lipid accumulation of hepatocytes induced by PA. Oil red O staining also demonstrated that ZXD improved the lipid accumulation in the liver of HFD mice. JC-1 staining for mitochondrial membrane potential indicated that ZXD effectively reversed the decrease in mitochondrial membrane potential caused by hepatocyte injury induced by PA, activated PGC-1α, and up-regulated the expression of its target genes, such as ACADS, CPT-1α, CPT-1β, UCP-1, ACSL-1, and NRF-1. In addition, as revealed by the Western blot and immunohistochemistry, ZXD up-regulated the protein expression levels of LKB1, p-AMPK, p-ACC, and PGC-1α in vivo and in vitro. In conclusion, ZXD can improve NAFLD and its mechanism may be related to the regulation of the LKB1/AMPK/PGC-1α pathway.

Effects of PGC1 / 中南大学学报(医学版)

OBJECTIVES@#Peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1α) controls mitochondrial biogenesis, but its role in cardiovascular diseases is unclear. The purpose of this study is to explore the effect of PGC1α on myocardial ischemia-reperfusion injury and the underlying mechanisms.@*METHODS@#The transverse coronary artery of SD rat was ligated for 30 minutes followed by 2 hours of reperfusion. Triphenyltetrazolium chloride (TTC) staining was performed to measure the area of myocardial infarction. Immunohistochemistry and Western blotting were used to detect the PGC1α expression in myocardium. The rat cardiomyocyte H9C2 was subjected to hypoxia/reoxygenation (H/R) with the knockdown of PGC1α or hypoxia- inducible factor 1α (HIF-1α), or with treatment of metformin. Western blotting was used to detect the expression of PGC1α, HIF-1α, p21, BAX, and caspase-3. CCK-8 was performed to detect cell viability, and flow cytometry was used to detect apoptosis and mitochondrial superoxide (mitoSOX) release. RT-qPCR was used to detect the mRNA expression of PGC1α and HIF-1α. Besides, chromatin immunoprecipitation (ChIP)-qPCR and luciferase reporter gene assay were applied to detect the transcriptional regulation effect of HIF-1α on PGC1α.@*RESULTS@#After I/R, the PGC1α expression was increased in infarcted myocardium. H/R induced H9C2 cell apoptosis (@*CONCLUSIONS@#After I/R, HIF-1α up-regulates the expression of PGC1α, leading to an increase in ROS production and aggravation of injury. Metformin can inhibit the accumulation of HIF-1α during hypoxia and effectively protect myocardium from ischemia/reperfusion injury.

Research progresses on PGC-1α, a key energy metabolic regulator / 生理学报

Disturbance of the energy balance, when the energy intake exceeds its expenditure, is a major risk factor for the development of metabolic syndrome (MS). The peroxisome proliferator activated receptor γ (PPARγ) coactivator-1α (PGC-1α) functions as a key regulator of energy metabolism and has become a hotspot in current researches. PGC-1α sensitively responds to the environmental stimuli and nutrient signals, and further selectively binds to different transcription factors to regulate various physiological processes, including glucose metabolism, lipid metabolism, and circadian clock. In this review, we described the gene and protein structure of PGC-1α, and reviewed its tissue-specific function in the regulation of energy homeostasis in various mammalian metabolic organs, including liver, skeletal muscle and heart, etc. At the meanwhile, we summarized the application of potential small molecule compounds targeting PGC-1α in the treatment of metabolic diseases. This review will provide theoretical basis and potential drug targets for the treatment of metabolic diseases.

Effects of Mitochondrial Dysfunction via AMPK/PGC-1 α Signal Pathway on Pathogenic Mechanism of Diabetic Peripheral Neuropathy and the Protective Effects of Chinese Medicine / 中国结合医学杂志

Diabetic peripheral neuropathy (DPN) is a progressive neurodegenerative disease of peripheral nervous system with high energy requirement. The adenosine monophosphate-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor- γ coactivator 1 α (PGC-1 α) axis plays a key role in regulating mitochondrial energy metabolism. Increasing preclinical evidences have shown that inhibition of AMPK/PGC-1 α pathway leading to mitochondrial dysfunction in neurons or Schwann cells contributes to neuron apoptosis, distal axonopathy and nerve demyelination in DPN. Some Chinese medicine formulae or extracts from herbs may have potential neuroprotective effects on DPN via activating AMPK/PGC-1 α pathway and improving mitochondrial function.

Generation of GABAergic interneuron-specific PGC-1α knockout mice / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To generate mice which are specific for peroxisomproliferator-activated receptor-γ coactivator-1(PGC-1α) knockout in the GABAergic interneuron.</p><p><b>METHODS</b>Conditional mice specific for PGC-1αwere introduced from the Jackson Laboratory, USA and initially inbred to obtain homozygote PGC-1αmice. The PGC-1αconditional mice were further crossed with Dlx5/6-Cre-IRES-EGFP transgenic mice to achieve specific knockout of PGC-1α in the GABAergic interneuron.</p><p><b>RESULTS</b>The offspring with specific knockout PGC-1α gene were successful for the generation of GABAergic interneuron, with the resulting genotype being PGC-1α.</p><p><b>CONCLUSION</b>The PGC-1αmice were obtained through a proper crossing strategy, which has provided a suitable platform for studying the function of PGC-1α in neuropsychiatric diseases.</p>

Early intervention with Didang decoction delays macrovascular lesions in diabetic rats through regulating AMP-activated protein kinase signaling pathway / 中国天然药物

The study aimed to investigate the intervening role of Didang decoction (DDD) at different times in macrovascular endothelial defense function, focusing on its effects on the AMP-activated protein kinase (AMPK) signaling pathway. The effects of DDD on mitochondrial energy metabolism were also investigated in rat aortic endothelial cells (RAECs). Type 2 diabetes were induced in rats by streptozotocin (STZ) combined with high fat diet. Rats were randomly divided into non-intervention group, metformin group, simvastatin group, and early-, middle-, late-stage DDD groups. Normal rats were used as control. All the rats received 12 weeks of intervention or control treatment. Western blots were used to detect the expression of AMP-activated protein kinase α1 (AMPKα1) and peroxisome proliferator-activated receptor 1α (PGC-1α). Changes in the intracellular AMP and ATP levels were detected with ELISA. Real-time-PCR was used to detect the mRNA level of caspase-3, endothelial nitric oxide synthase (eNOS), and Bcl-2. Compared to the diabetic non-intervention group, a significant increase in the expression of AMPKα1 and PGC-1α were observed in the early-stage, middle-stage DDD groups and simvastatin group (P < 0.05). The levels of Bcl-2, eNOS, and ATP were significantly increased (P < 0.05), while the level of AMP and caspase-3 were decreased (P < 0.05) in the early-stage DDD group and simvastatin group. Early intervention with DDD enhances mitochondrial energy metabolism by regulating the AMPK signaling pathway and therefore may play a role in strengthening the defense function of large vascular endothelial cells and postpone the development of macrovascular diseases in diabetes.

Inhibitory effects of SRT1720 on the apoptosis of rabbit chondrocytes by activating SIRT1 via p53/bax and NF-κB/PGC-1α pathways / 华中科技大学学报（医学）（英德文版）

SRT1720, a new discovered drug, was reported to activate silent information regulator 1 (SIRT1) and inhibit the chondrocyte apoptosis. However, the underlying mechanism remains elusive. In the present study, the chondrocytes were extracted from the cartilage tissues of New Zealand white rabbits, cultured in the presence of sodium nitroprusside (SNP) (2.5 mmol/L) and divided into five groups: 1, 5, 10, and 20 μmol/L SRT1720 groups and blank control group (0 μmol/L SRT1720). MTT assay was used to detect the chondrocyte viability and proliferation, and DAPI staining and flow cytometry to measure the chondrocyte apoptosis. The expression levels of SIRT1, p53, NF-κB/p65, Bax, and peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) were detected by Western blotting and the expression levels of SIRT1, type II collagen, and aggrecan mRNA by RT-PCR. The results showed that in the SRT1720-treated groups, the nuclei of chondrocytes were morphologically intact and had uniform chromatin. In the blank control group, nuclear rupture into debris was observed in chondrocytes. With the SRT1720 concentration increasing, the chondrocyte viability increased, the apoptosis rate decreased, the protein expression levels of SIRT1 and PGC-1α and the mRNA expression levels of type II collagen and aggrecan increased ({ptP}<0.05), and the expression levels of p53, NF-κB and bax decreased (P<0.05). It was suggested that SRT1720 inhibits chondrocyte apoptosis by activating the expression of SIRT1 via p53/bax and NF-κB/PGC-1α pathways.

Expressions of inflammatory and fibrogenic factors in perinephric and subcutaneous adipose tissues of patients with adrenocorticotropic hormone-independent Cushing's syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the expressions of inflammation- and fibrosis-related genes in perinephric and subcutaneous adipose tissues in patients with adrenocorticotropic hormone (ACTH)-independent Cushing's syndrome.</p><p><b>METHODS</b>The perinephric and subcutaneous adipose tissues adipose tissues were obtained from 8 patients with ACTH-independent Cushing's syndrome undergoing laparoscopic retroperitoneal adrenalectomy. Real-time PCR was used to detect the mRNA expression levels of interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), matrix metallopeptidase 2 (MMP-2), TIMP metallopeptidase inhibitor 1 (TIMP-1), early growth response 1 (EGR1), CCAAT/enhancer binding protein β(CEBPβ), uncoupling protein 1(UCP-1), PPARγ coactivator 1 alpha (PGC1α) and cell death-inducing DFFA-like effector a (CIDEA).</p><p><b>RESULTS</b>The mRNA level of CIDEA was significantly higher in the perinephric adipose tissue (peri-N) than in the subcutaneous adipose tissue (subQ) (P<0.05). The expressions of CEBPβ, UCP-1, and PGC1α mRNA in the peri-N were similar with those in the subQ. The expressions of IL-6, TIMP1 and EGR1 mRNA in the subQ were significantly higher than those in the peri-N (P<0.05). No significant difference in TNF-α and MMP-2 mRNA levels was found between peri-N and subQ.</p><p><b>CONCLUSION</b>The expression levels of the inflammation- and fibrosis-related genes are higher in the subQ than in the peri-N of patients with ACTH-independent Cushing's syndrome, suggesting that chronic exposure to endogenous hypercortisolism may cause adipose tissue dysfunction.</p>

Bofutsushosan ameliorates obesity in mice through modulating PGC-1α expression in brown adipose tissues and inhibiting inflammation in white adipose tissues / 中国天然药物

The inducible co-activator PGC-1α plays a crucial role in adaptive thermogenesis and increases energy expenditure in brown adipose tissue (BAT). Meanwhile, chronic inflammation caused by infiltrated-macrophage in the white adipose tissue (WAT) is a target for the treatment of obesity. Bofutsushosan (BF), a traditional Chinese medicine composed of 17 crude drugs, has been widely used to treat obesity in China, Japan, and other Asia countries. However, the mechanism underlying anti-obesity remains to be elucidated. In the present study, we demonstrated that BF oral administration reduced the body weight of obese mice induced by high-fat diet (HFD) and alleviated the level of biochemical markers (P < 0.05), including blood glucose (Glu), total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL-C) and insulin. Our further results also indicated that oral BF administration increased the expression of PGC-1α and UCP1 in BAT. Moreover, BF also reduced the expression of inflammatory cytokines in WAT, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). These findings suggested that the mechanism of BF against obesity was at least partially through increasing gene expression of PGC-1α and UCP1 for energy consumption in BAT and inhibiting inflammation in WAT.

Effects of endurance training on reduction of plasma glucose during high intensity constant and incremental speed tests in Wistar rats

The aim of this research was to investigate the effects of endurance training on reduction of plasma glucose during high intensity constant and incremental speed tests in Wistar rats. We hypothesized that plasma glucose might be decreased in the exercised group during heavy (more intense) exercise. Twenty-four 10-week-old male Wistar rats were randomly assigned to sedentary and exercised groups. The prescription of endurance exercise training intensity was determined as 60% of the maximum intensity reached at the incremental speed test. The animals were trained by running on a motorized treadmill, five days/week for a total period of 67 weeks. Plasma glucose during the constant speed test in the exercised group at 20 m/min was reduced at the 14th, 21st and 28th min compared to the sedentary group, as well at 25 m/min at the 21st and 28th min. Plasma glucose during the incremental speed test was decreased in the exercised group at the moment of exhaustion (48th min) compared to the sedentary group (27th min). Endurance training positively modulates the mitochondrial activity and capacity of substrate oxidation in muscle and liver. Thus, in contrast to other studies on high load of exercise, the effects of endurance training on the decrease of plasma glucose during constant and incremental speed tests was significantly higher in exercised than in sedentary rats and associated with improved muscle and hepatic oxidative capacity, constituting an important non-pharmacological intervention tool for the prevention of insulin resistance, including type 2 diabetes mellitus.

Protective Effects of Cornus Officinalis Total Glycosides and Cornus Polysaccharides on Myocardial Mitochondria of Acute Myocardial Infarction Rats: an Experimental Study / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the effect of Cornus Officinalis total glycosides (COTG) and Cornus polysaccharides (CP) on myocardial mitochondria and expression levels of glycogen synthase kinase-3β (GSK-3β) of acute myocardial infarction (AMI) rats.</p><p><b>METHODS</b>The AMI rat model was established by ligating the left anterior descending branch of coronary artery. Rats were divided into 5 groups according to random digit table, i.e., the sham-operation group, the model group, the COTG prevention group, the CP treatment group, the COTG treatment group, 12 in each group. Normal saline was administered to rats in the normal control group and the model group by gastrogavage. Corresponding medication was respectively administered to rats in the rest 3 groups by gastrogavage. The cardiac function was detected by echocardiography and hemodynamics. The infarct size was determined by Masson trichrome staining. The expression of mitochondrial biogenesis genes such as a subunit of peroxisome proliferators-activated receptor-γ coactivator-1 (PGC-1α), PGC-1β, nuclear respiratory factor-1 (NRF-1), and GSK-3P mRNA were detected by Real-time PCR.</p><p><b>RESULTS</b>Compared with the sham-operation group, the myocardial infarction size increased, cardiac function decreased, the expression of PGC-1α, PGC-1β, and NRF-1 mRNA decreased, and the expression of GSK-3β mRNA increased (all P <0. 05). Compared with the model group, myocardial infarction sizes were reduced, cardiac function was improved, the expression of NRF-1 mRNA was elevated in the COTG prevention group, the CP treatment group, the COTG treatment group; the expression of the PGC-1α and PGC-1β mRNA was elevated in the COTG prevention group and the CP treatment group; the expression of GSK-3β mRNA was reduced in the CP treatment group (all P <0. 05). Compared with the CP prevention group, fractional shortening (FS) and aortic systolic blood pressure (SBP) increased in the CP treatment group; ejection fraction (EF) decreased in the CP treatment group; the expression of PGC-1α, PGC-1β, NRF-1 mRNA were reduced in the the CP treatment group and the COTG treatment group; the expression of GSK-3β mRNA decreased in the CP treatment group (all P <0. 05). Compared with the COTG treatment group, FS, EF, left ventricular end systolic pressure (LVESP), SBP, and the expression of GSK-3β mRNA were reduced in the CP treatment group (P <0. 05).</p><p><b>CONCLUSIONS</b>COTG and CP could improve cardiac function, reduce the myocardial infarction area, and promote biogenesis of myocardial mitochondria. Their protective effects on the mitochondria of cadiocytes might be achieved by GSK-3β signalina pathway.</p>

Mongolian medicine cha gan beng ga regulated activity of biomarker PGC-1α / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the regulation of Cha Gan Beng Ga on the activity of biomarker PGC-1α in vivo and in vitro, and lay the foundation for studying the efficacy result of Cha Gan Beng Ga on xenograft tumor model and extracting active constituents.</p><p><b>METHOD</b>(1) The coarse powder of Cha Gan Beng Ga was extracted with 70% ethanol solution through heating and refluxing, and finally was used to freeze dry powder. (2) 50 mg x kg(-1) of freeze-dried power was orally administrated to KM and C57BL/6J mice once daily, lasting for 5 consecutive days; different concentrations of extracted materials was given to non-small cell lung cells A549. (3) The expression level of PGC-1α mRNA was quantitatively determined in lung tissue of mice and non-small cell lung cells A549.</p><p><b>RESULT</b>The expression levels of PGC-1α in lung tissue of different mice strains had an increasing tendency. Furthermore, the expression levels of PGC-1α in non-small cell lung cells A549 also had an increasing tendency, showing dose and time-dependent relationships.</p><p><b>CONCLUSION</b>Mongolian Medicine Cha Gan Beng Ga could induce the over-expression of PGC-1α mRNA in lung tissue of mice and in non-small cell lung cells A549. The present results will lay foundation for studying the efficacy result of antitumor and active constitutes in future.</p>

Recent advances in the study of AMPK and inflammatory pulmonary disease / 药学学报

AMP-activated protein kinase (AMPK) is an important regulator of cellular energy homeostasis. Recent studies demonstrated that AMPK is a novel signaling molecule modulating inflammatory responses and oxidative stress which are involved in inflammatory pulmonary diseases, such as asthma, chronic obstructive pulmonary disease (COPD), pulmonary infectious diseases and pulmonary fibrosis. AMPK attenuates inflammatory lung injury by phosphorylating its downstream targets, such as sirtuin1 (SIRT1), peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha), p53 and forkhead box O3a (FoxO3a). This review summarized the relationship between AMPK and the development of inflammatory pulmonary diseases.

Screening of variation in the promoter of PPARGC1A gene and study of its association with the risk of type 2 diabetes in ethnic Hans from Beijing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the baseline distribution of polymorphisms in the promoter of peroxisome proliferators activated receptor co-activator 1 (PPARGC1A) gene in ethnic Hans from Beijing, and to assess their association with type 2 diabetes (T2DM).</p><p><b>METHODS</b>A 2-stage study was designed. Firstly, the promoter region of PPAGC1A gene was screened with PCRRFLP in a small population (n=216, T2DM/control: 104/112), which was followed by a replication study of a larger group (n=1546, T2DM/control: 732/814). Fasting plasma glucose, insulin, blood lipid, height, weight, waist circumference, and blood pressure were measured in all subjects. Potential association was assessed by logistic regression. Linkage disequilibrium and haplotype analysis were conducted with Haploview software.</p><p><b>RESULTS</b>Five polymorphisms were identified with Sanger sequencing, among which T-2120C (rs3755857), -1999C/G (rs2946386) and -1437T/C (rs2970870) were included for genotypic analysis based on their moderate levels of heterozygosity. No significant difference was found between the two groups. When adjusted for age and gender confounding, we have combined the OR values from population 1 and population 2 based on Mantel-Haenszel fixed model, and recognized a mild contribution of C allele of -1999C/G (rs2946386) to the 1.18-fold risk of T2DM (P=0.03, OR=118). No haplotype was associated with T2DM after permutation correction.</p><p><b>CONCLUSION</b>The C allele of -1999C/G ( rs2946386) in the promoter region of the PPARGC1A gene is mildly associated with T2DM. Variations in the promoter region of the PPARGC1A gene seem not to confer the risk of T2DM in our population.</p>

Study of peroxisome proliferator-activated receptor-γ coactivator-1α expression and cytoapoptosis in masseter muscles of unilateral chewing rat / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the changes of peroxisome proliferator- activated receptor-γ coactivator -1α (PGC-1α) mRNA and cytoapoptosis in the rats' masseter muscle which had been influenced by unilateral chewing, and to explore the theoretical foundation of changes in masticatory muscles induced by unilateral chewing.</p><p><b>METHODS</b>The animal models were established by extracting the Wistar rats' left maxillary molars. Thirty- six female Wistar rats were randomly divided into four groups of 2, 4, 6 and 8 weeks, nine each. In each group there were six rats with molar extracted and three as control. The Ca²⁺ level was detected by atomic spectrophotometric method. The relative expression of PGC-1α mRNA was detected by real- time fluorescent quantitative PCR. The apoptosis index was detected by Hoechst staining.</p><p><b>RESULTS</b>The Ca²⁺ level in the muscle on the extraction side were significantly higher than that in the controls in the beginning stage of unilateral chewing, and reached the peak at the 4th week [(43.62 ± 2.36) µg/g]. The relative expressions of PGC-1α increased from the beginning and reached the maximum level at the 4th week [extraction side: (1.57 ± 0.10); non-extraction side: (1.92 ± 0.06)], while the relative expressions of PGC-1α in 6 and 8 weeks decreased gradually [extraction side: (1.06 ± 0.08), (1.08 ± 0.07); non- extraction side: (1.09 ± 0.10), (1.11 ± 0.08)]. The changes of apoptosis index on non- extraction side increased continually and peaked at the 6th week [(38.56 ± 1.64)%].</p><p><b>CONCLUSIONS</b>PGC-1α and cytoapoptosis played important roles in different stages of tissue remodeling induced by unilateral chewing.</p>

Effects of pioglitazone on myocardial peroxisome proliferator-activated receptor gamma co-activator lα expression in rats with myocardial ischemia/reperfusion injury / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of pioglitazone on the expression of peroxisome proliferator-activated receptor gamma co-activator lα (PGC-lα) in rat myocardium following myocardial ischemia/reperfusion (I/R) injury.</p><p><b>METHODS</b>Twenty-four SD rats were randomly divided into 4 equal groups, namely I/R group, pioglitazone (5 mg/kg daily) group, pioglitazone (10 mg/kg daily) group, and pioglitazone (10 mg/kg) +peroxisome proliferator-activated receptor γ (PPARγ)-specific antagonist GW9662 group. Myocardial I/R injury was induced by ligation of the left anterior descending coronary artery for 30 min and reperfusion for 120 min. Myocardial apoptosis following I/R injury was examined with TUNEL assay; RT-PCR and Western blotting were employed to detect the expression of PGC-lα mRNA and protein, respectively.</p><p><b>RESULTS</b>Pioglitazone treatment significantly suppressed myocardial apoptosis (21.4%∓8.8%,17.3%∓8.7%, 40.1%∓12.3%, P<0.05) following I/R injury and up-regulated myocardial PGC-lα expression at both the mRNA and protein levels (P<0.05), but these effects were antagonized by GW9662 (P<0.05).</p><p><b>CONCLUSION</b>Pioglitazone can inhibit myocardial apoptosis induced by I/R injury and up-regulate myocardial PGC-lα expression, and these effects are mediated by PPARγ.</p>

Effect of pure total flavonoids from citrus on hepatic SIRT1/PGC-1alpha pathway in mice with NASH / 中国中药杂志

<p><b>OBJECTIVE</b>To observe the effect of pure total flavonoids from Citrus (PTFC) on the hepatic fatty degeneration, inflammation, oxidative stress and SIRT1/PGC-1alpha expressions in mice with non-alcohol steatohepatitis (NASH), and discuss the action mechanism of PTFC on NASH.</p><p><b>METHOD</b>Mice were given high-fat diet for 16 weeks to induce the NASH model. Since the seventh week after the model establishment, the mice were intervened with 100, 50 and 25 mg x kg(-1) x d(-1) PTFC for 10 weeks. The pathologic changes in hepatic tissues were observed with HE staining. The contents of TG, CHOL in hepatic tissue, as well as the levels of AST, ALT in serum were detected by using the biochemical process. The expression of SIRT1, PGC-1alpha and MnSOD mRNA in hepatic tissues were detected with Real-time PCR assay. SIRT1, PGC-1alpha protein and 8-OHdG expressions were determined with the immunohistochemical method. The SOD level in hepatic tissues was tested by the xanthine oxidase method. The MDA content in hepatic tissues was examined by the thiobarbituric acid method.</p><p><b>RESULT</b>The contents of TG, CHOL, NAFLD activity scores and ALT level in serum in hepatic tissues of mice in the model induced by fat-rich diet were obviously higher than that of the normal group (P < 0.010. The SIRT1, PGC-1alpha, MnSOD mRNA and protein expression in hepatic tissues were significantly lower than that of the normal group (P < 0.01). The expression of 8-OHdG and the content of MDA in hepatic tissues were obviously higher than that of the normal group (P < 0.01). After the intervention with different doses of PTFC, the NAFLD activity scores, the content of TG and the level of AST in serum were notably lower than that of the normal group (P < 0.01, P < 0.05); whereas the SIRT1, PGC-1alpha, MnSOD mRNA and protein expression were obviously higher than that of the normal group (P < 0.01, P < 0.05), with the significant decrease in the expression of 8-OHdG and the content of MDA (P < 0.01).</p><p><b>CONCLUSION</b>Oxidative stress/lipid peroxidation enhancement in in NASH mice induced by high-fat diet may be related to the changes in SIRT1/PGC-1alpha signal transduction pathway. PTFC could enhance the anti-oxidant capacity in liver, relieve the damage of reactive oxygen during the fatty acid metabolic process, and prevent NASH from the occurrence and development by regulating the SIRT1/PGC-1alpha signal pathway.</p>