Upregulation of PGC-1α expression by pioglitazone mediates prevention of sepsis-induced acute lung injury

Abstract The imbalance between pro-inflammatory M1 and anti-inflammatory M2 macrophages plays a critical role in the pathogenesis of sepsis-induced acute lung injury (ALI). Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) may modulate macrophage polarization toward the M2 phenotype by altering mitochondrial activity. This study aimed to investigate the role of the PGC-1α agonist pioglitazone (PGZ) in modulating sepsis-induced ALI. A mouse model of sepsis-induced ALI was established using cecal ligation and puncture (CLP). An in vitro model was created by stimulating MH-S cells with lipopolysaccharide (LPS). qRT-PCR was used to measure mRNA levels of M1 markers iNOS and MHC-II and M2 markers Arg1 and CD206 to evaluate macrophage polarization. Western blotting detected expression of peroxisome proliferator-activated receptor gamma (PPARγ) PGC-1α, and mitochondrial biogenesis proteins NRF1, NRF2, and mtTFA. To assess mitochondrial content and function, reactive oxygen species levels were detected by dihydroethidium staining, and mitochondrial DNA copy number was measured by qRT-PCR. In the CLP-induced ALI mouse model, lung tissues exhibited reduced PGC-1α expression. PGZ treatment rescued PGC-1α expression and alleviated lung injury, as evidenced by decreased lung wet-to-dry weight ratio, pro-inflammatory cytokine secretion (tumor necrosis factor-α, interleukin-1β, interleukin-6), and enhanced M2 macrophage polarization. Mechanistic investigations revealed that PGZ activated the PPARγ/PGC-1α/mitochondrial protection pathway to prevent sepsis-induced ALI by inhibiting M1 macrophage polarization. These results may provide new insights and evidence for developing PGZ as a potential ALI therapy.

Study on the relationship between relieving energy crisis in myofascial trigger points with An-Pressing manipulation and AMPK/PGC-1α pathway activation / 针灸推拿医学（英文版）

Objective: To explore the mechanism of An-Pressing manipulation in relieving energy crisis in chronic myofascial trigger points (MTrPs) by observing the effects of An-Pressing manipulation on adenosine triphosphate (ATP), adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) pathway and mitochondrial ultrastructure of skeletal muscle cells in MTrPs rats. Methods: Forty-eight male Sprague-Dawley rats were randomly divided into a blank group, a model group, a lidocaine group, and an An-Pressing manipulation group, with 12 rats in each group. The model group, lidocaine group and An-Pressing manipulation group were used to replicate the MTrPs rat model by blunt shock and centrifugal motion method. After modeling, the An-Pressing manipulation group was subjected to 7 times An-Pressing manipulation, once every other day; the lidocaine group was treated with 3 times of injection of lidocaine at the MTrPs, once every 6 d. The blank group and the model group were fed normally without intervention. After the intervention, local muscle tissue was taken to detect the content of ATP and the expression of AMPK, phosphorylated AMPK (phospho-AMPK), PGC-1α, and glucose transporter 4 (GluT4), and the ultrastructure of mitochondria was observed under an electron microscope. Results: Compared with the blank group, the ATP content in the model group was decreased (P<0.05), the protein expression levels of phospho-AMPK, PGC-1α, and GluT4 and the ratio of phospho-AMPK to AMPK were decreased (P<0.05); under the electron microscope, the number of mitochondria decreased, and they were deformed, small in volume, and had deformed cristae. Compared with the model group, the ATP contents in the An-Pressing manipulation group and the lidocaine group were increased (P<0.05), and the protein expression levels of phospho-AMPK, PGC-1α, and GluT4 and the ratio of phospho-AMPK to AMPK were increased (P<0.05); under the electron microscope, the number of mitochondria increased, the shape and size of the mitochondria were basically normal, and the cristae could be seen. Compared with the lidocaine group, phospho-AMPK and the ratio of phospho-AMPK to AMPK in the An-Pressing manipulation group were increased (P<0.05); under the electron microscope, the numbers of mitochondria were similar, and the shape and size of the mitochondria were basically normal without swelling, and the cristae could be observed. Conclusion: An-Pressing manipulation can increase the ATP content in MTrPs tissue, improve the expression levels of PGC-1α and GluT4 proteins and the ratio of phospho-AMPK to AMPK; its mechanism may relate to the activation of AMPK/PGC-1α signaling pathway to promote the repair of mitochondrial damages.

Da Chaihutang Protects Liver Mitochondrial Function of Nutritionally Obese Rats via CREB/PGC-1α Pathway / 中国实验方剂学杂志

Objective:To observe the effects of Da Chaihutang on Cyclic adenosine monophosphate （cAMP）-response element binding protein （CREB）/peroxisome proliferator-activated receptor-gamma coactivator-1 alpha （PGC-1<italic>α</italic>） pathway in nutritionally obese rats and the protective mechanism on liver mitochondria. Method:A total of 120 8-week-old male SD rats were randomly divided into a control group （<italic>n</italic>=20） and an experimental group （<italic>n</italic>=100）. The rats in the control group were fed on a normal diet， while those in the experimental group were administered with a high-fat feed. Successfully modeled rats were randomly divided into a model group， a positive drug （metformin） group， and low-， medium- and high-dose Da Chaihutang groups （4.25， 8.5， and 17 g∙kg^-1， respectively）， with 20 rats in each group. After treatment with Da Chaihutang， the body weight， Lee's index， liver mitochondrial membrane potential and mitochondrial ultrastructure， PGC-1<italic>α </italic>expression and CREB phosphorylation of each group were measured and compared. Result:Compared with the control group， the model group showed increased body weight and Lee's index （<italic>P</italic><0.01）， whereas decreased mitochondrial membrane potential， PGC-1<italic>α</italic> expression， and CREB phosphorylation level （<italic>P</italic><0.01）. As compared with the model group， Da Chaihutang significantly reduced the body weight and Lee's index of obese rats （<italic>P</italic><0.05， <italic>P</italic><0.01）， enhanced liver mitochondrial membrane potential （<italic>P</italic><0.05， <italic>P</italic><0.01） to protect the integrity of mitochondrial structure， up-regulated PGC-1<italic>α</italic> expression and promoted CREB phosphorylation （<italic>P</italic><0.05， <italic>P</italic><0.01）. Conclusion:Da Chaihutang protects the structure and function of mitochondria and inhibits weight gain in obese rats by activating the CREB/PGC-1<italic>α</italic> pathway.

Research progress of effect and mechanism of PGC-1α in cardiovascular diseases / 解放军医学杂志

Cardiovascular disease is currently the number one killer of human health. Studies have shown that peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is a key factor in physiological processes such as energy metabolism and oxidative stress, which also involved in regulating mitochondrial biosynthesis. PGC-1α is closely related to the occurrence and development of atherosclerosis, coronary heart disease, atrial fibrillation, cardiomyopathy, myocardial hypertrophy, heart failure and other cardiovascular diseases. This article briefly describes the research progress of PGC-1α in cardiovascular diseases.

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.

Association of peroxisome proliferator-activated receptor gamma coactivator 1 alpha rs8192678 single nucleotide polymorphism with the risk of nonalcoholic fatty liver disease / 临床肝胆病杂志

ObjectiveTo investigate the association of peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PPARGC1A) rs8192678 single nucleotide polymorphism (SNP) with the risk of nonalcoholic fatty liver disease (NAFLD) and the influence of PPARGC1A rs8192678 SNP on NAFLD-related biochemical parameters. MethodsA total of 119 NAFLD patients who attended Qingdao Municipal Hospital Affiliated to Qingdao University from December 2017 to December 2018 were enrolled as NAFLD group, and 213 individuals who underwent physical examination during the same period of time were enrolled as control group. Clinical data and blood samples were collected from all subjects to measure related biochemical parameters and detect PPARGC1A rs8192678 SNP. The chi-square test was used to determine whether the genotype distribution of samples was in accordance with the Hardy-Weinberg equilibrium. The t-test or the Wilcoxon rank-sum test was used for comparison of continuous data between two groups, and the chi-square test was used for comparison of categorical data between two groups. A binary logistic regression analysis was used to investigate the risk factors for NAFLD. ResultsThere were no significant differences in the genotype and allele frequencies of PPARGC1A rs8192678 between the NAFLD group and the control group (χ2=0.011 and 0.015, P=0.918 and 0.904). The binary logistic regression analysis showed that CT genotype of PPARGC1A rs8192678 was not a risk factor for NAFLD (odds ratio=0.951, 95% confidence interval: 0.368-2.457, P=0.918). In the NAFLD group, the patients carrying CT genotype had a significantly higher level of gamma-glutamyl transpeptidase (GGT) than those carrying CC genotype (Z=-2.331, P=0.020). ConclusionPPARGC1A rs8192678 SNP does not increase the risk of NAFLD, while NAFLD patients carrying CT genotype tend to have a higher serum level of GGT.

Effect of the Shensong Yangxin Capsule on Energy Metabolism in Angiotensin II-Induced Cardiac Hypertrophy / 中华医学杂志(英文版)

<p><b>Background</b>Shensong Yangxin Capsule (SSYX), traditional Chinese medicine, has been used to treat arrhythmias, angina, cardiac remodeling, cardiac fibrosis, and so on, but its effect on cardiac energy metabolism is still not clear. The objective of this study was to investigate the effects of SSYX on myocardium energy metabolism in angiotensin (Ang) II-induced cardiac hypertrophy.</p><p><b>Methods</b>We used 2 μl (10 mol/L) AngII to treat neonatal rat cardiomyocytes (NRCMs) for 48 h. Myocardial α-actinin staining showed that the myocardial cell volume increased. Expression of the cardiac hypertrophic marker-brain natriuretic peptide (BNP) messenger RNA (mRNA) also increased by real-time polymerase chain reaction (PCR). Therefore, it can be assumed that the model of hypertrophic cardiomyocytes was successfully constructed. Then, NRCMs were treated with 1 μl of different concentrations of SSYX (0.25, 0.5, and 1.0 μg/ml) for another 24 h. To explore the time-depend effect of SSYX on energy metabolism, 0.5 μg/ml SSYX was added into cells for 0, 6, 12, 24, and 48 h. Mitochondria was assessed by MitoTracker staining and confocal microscopy. mRNA and protein expression of mitochondrial biogenesis-related genes - Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), energy balance key factor - adenosine monophosphate-activated protein kinase (AMPK), fatty acids oxidation factor - carnitine palmitoyltransferase-1 (CPT-1), and glucose oxidation factor - glucose transporter- 4 (GLUT-4) were measured by PCR and Western blotting analysis.</p><p><b>Results</b>With the increase in the concentration of SSYX (from 0.25 to 1.0 μg/ml), an increased mitochondrial density in AngII-induced cardiomyocytes was found compared to that of those treated with AngII only (0.25 μg/ml, 18.3300 ± 0.8895 vs. 24.4900 ± 0.9041, t = 10.240, P < 0.0001; 0.5 μg/ml, 18.3300 ± 0.8895 vs. 25.9800 ± 0.8187, t = 12.710, P < 0.0001; and 1.0 μg/ml, 18.3300 ± 0.8895 vs. 24.2900 ± 1.3120, t = 9.902, P < 0.0001; n = 5 per dosage group). SSYX also increased the mRNA and protein expression of PGC-1α (0.25 μg/ml, 0.8892 ± 0.0848 vs. 1.0970 ± 0.0994, t = 4.319, P = 0.0013; 0.5 μg/ml, 0.8892 ± 0.0848 vs. 1.2330 ± 0.0564, t = 7.150, P < 0.0001; and 1.0 μg/ml, 0.8892 ± 0.0848 vs. 1.1640 ± 0.0755, t = 5.720, P < 0.0001; n = 5 per dosage group), AMPK (0.25 μg/ml, 0.8872 ± 0.0779 vs. 1.1500 ± 0.0507, t = 7.239, P < 0.0001; 0.5 μg/ml, 0.8872 ± 0.0779 vs. 1.2280 ± 0.0623, t = 9.379, P < 0.0001; and 1.0 μg/ml, 0.8872 ± 0.0779 vs. 1.3020 ± 0.0450, t = 11.400, P < 0.0001; n = 5 per dosage group), CPT-1 (1.0 μg/ml, 0.7348 ± 0.0594 vs. 0.9880 ± 0.0851, t = 4.994, P = 0.0007, n = 5), and GLUT-4 (0.5 μg/ml, 1.5640 ± 0.0599 vs. 1.7720 ± 0.0660, t = 3.783, P = 0.0117; 1.0 μg/ml, 1.5640 ± 0.0599 vs. 2.0490 ± 0.1280, t = 8.808, P < 0.0001; n = 5 per dosage group). The effect became more obvious with the increasing concentration of SSYX. When 0.5 μg/ml SSYX was added into cells for 0, 6, 12, 24, and 48 h, the expression of AMPK (6 h, 14.6100 ± 0.6205 vs. 16.5200 ± 0.7450, t = 3.456, P = 0.0250; 12 h, 14.6100 ± 0.6205 vs. 18.3200 ± 0.9965, t = 6.720, P < 0.0001; 24 h, 14.6100 ± 0.6205 vs. 21.8800 ± 0.8208, t = 13.160, P < 0.0001; and 48 h, 14.6100 ± 0.6205 vs. 23.7400 ± 1.0970, t = 16.530, P < 0.0001; n = 5 per dosage group), PGC-1α (12 h, 11.4700 ± 0.7252 vs. 16.9000 ± 1.0150, t = 7.910, P < 0.0001; 24 h, 11.4700 ± 0.7252 vs. 20.8800 ± 1.2340, t = 13.710, P < 0.0001; and 48 h, 11.4700 ± 0.7252 vs. 22.0300 ± 1.4180, t = 15.390; n = 5 per dosage group), CPT-1 (24 h, 15.1600 ± 1.0960 vs. 18.5800 ± 0.9049, t = 6.048, P < 0.0001, n = 5), and GLUT-4 (6 h, 10.2100 ± 0.9485 vs. 12.9700 ± 0.8221, t = 4.763, P = 0.0012; 12 h, 10.2100 ± 0.9485 vs. 16.9100 ± 0.8481, t = 11.590, P < 0.0001; 24 h, 10.2100 ± 0.9485 vs. 19.0900 ± 0.9797, t = 15.360, P < 0.0001; and 48 h, 10.2100 ± 0.9485 vs. 14.1900 ± 0.9611, t = 6.877, P < 0.0001; n = 5 per dosage group) mRNA and protein increased gradually with the prolongation of drug action time.</p><p><b>Conclusions</b>SSYX could increase myocardial energy metabolism in AngII-induced cardiac hypertrophy. Therefore, SSYX might be considered to be an alternative therapeutic remedy for myocardial hypertrophy.</p>

Effects of inducible hypothermia on expressions of PGC-1 and SHP in rat model of hemorrhagic shock / 中华急诊医学杂志

Objective To investigate the effects of inducible hypothermia on expressions of peroxisome proliferator activated receptor gamma coactivator-1 (PGC-1) and small heterodimer partner (SHP) in rat model of hemorrhagic shock.Methods SD rats were randomly (random number) divided into three groups:control (C),normothermia (N) and hypothermia (H).Exsanguination was carried out in rats by continuously drawing out venous blood (25 mL/kg) over 15 minutes to establish hemorrhagic shock model.Then,rectal temperatures of rats were maintained by body surface cooling to 32℃ in H group and by body surface warming to 38℃ in N group,respectively.After a shock period of 60 minutes,rats received the infusion of whole blood of their own and lactated Ringer's solution (1 ∶ 2) treatment for 60 min.Rats were warmed to 38℃ by body surface warming and monitored for 3 h after resuscitation.Hematocrit (Hct),base excess (BE),lactate (Lac),and glucose (Glu) were recorded before modeling and after different lengths of hemorrhagic shock period (HSP).The expressions of PGC-1 mRNA and SHP mRNA and the levels of their protein in liver were tested by real-time reverse transcription polymerase chain reaction (qRT-PCR) and western blotting,respectively.Results The H group had lower lactate levels and higher BElevels than the N group [(6.3±2.1) vs.(10.4±1.5) and (-4.7±2.5) vs.(-9.0±3.2)] (P＜ 0.05).At 72 hours after modeling,there were four survivors in the N group and seven survivors in the H group (P ＜ 0.05,Log Rank).The expressions of PGC-1 mRNA and SHP mRNA increased in N group.Hypothermia resuscitation down-regulated PGC-1 mRNA expression,meanwhile,increased expression of SHP mRNA.Both Hypothermia and Normothermia resuscitation increased SHP protein levels,but decreased PGC-1 protein levels.Conclusions Inducible hypothermia ameliorated acidosis and energy metabolism imbalance through adaptive regulation in PGC-1 and SHP.

Role of RIP140 and PGC-1αin angiotensin Ⅱ mediated energy metabolism in cardiomyocytes / 中国药理学通报

Aim To investigate the role of transcrip-tional cofactors receptor interacting protein 140 ( RIP140 ) and peroxisome proliferator-activated recep-tor γ coactivator-1α ( PGC-1α) in the angiotensin Ⅱ( AngⅡ) mediated energy metabolism regulation in cardiomyocytes. Methods RIP140 or PGC-1α was overexpressed via adenovirus vector system. ATP con-tents were detected by luminescence detection assay system. Real-time PCR and Western blot analysis were used to measure the expressions of RIP140 and PGC-1α genes. Results After treated with 100 nmol·L-1 AngⅡfor 36h in neonatal cardiomyocytes, the content of mitochondrial ATP was reduced notably ( P <0. 01). Accordingly, the mRNA and protein levels for RIP140 were increased. However, the mRNA and pro-tein levels of PGC-1α were downregulated markedly. What’ s more,the reduction of ATP induced by AngⅡwas further aggravated by RIP 1 4 0 overexpression , but ameliorated by overexpressing PGC-1α. Conclusion The reduction of ATP mediated by AngⅡis associated with the upregulation of RIP140 , as well as the down-regulation of PGC-1α.

Sterol-independent repression of low density lipoprotein receptor promoter by peroxisome proliferator activated receptor gamma coactivator-1alpha (PGC-1alpha)

Peroxisome proliferator activated receptor (PPAR) gamma coactivator-1alpha (PGC-1alpha) may be implicated in cholesterol metabolism since PGC-1alpha co-activates estrogen receptor alpha (ERalpha) transactivity and estrogen/ERalpha induces the transcription of LDL receptor (LDLR). Here, we show that overexpression of PGC-1alpha in HepG2 cells represses the gene expression of LDLR and does not affect the ERalpha-induced LDLR expression. PGC-1alpha suppressed the LDLR promoter-luciferase (pLR1563-luc) activity regardless of cholesterol or functional sterol-regulatory element-1. Serial deletions of the LDLR promoter revealed that the inhibition by PGC-1alpha required the LDLR promoter regions between -650 bp and -974 bp. Phosphorylation of PGC-1alpha may not affect the suppression of LDLR expression because treatment of SB202190, a p38 MAP kinase inhibitor, did not reverse the LDLR down-regulation by PGC-1alpha. This may be the first report showing the repressive function of PGC-1alpha on gene expression. PGC-1alpha might be a novel modulator of LDLR gene expression in a sterol-independent manner, and implicated in atherogenesis.