Peroxisome Proliferator-activated Receptor-γ Coactivator-1α Research Articles

Acupuncture modulates the AMPK/PGC-1 signaling pathway to facilitate mitochondrial biogenesis and neural recovery in ischemic stroke rats

AimsThe main objective of this study was to investigate the role and mechanism of acupuncture on anti-nerve injury in the acute phase by regulating mitochondrial energy metabolism via monophosphate-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) axis in rat ischemic stroke.Main methodsMiddle cerebral artery occlusion (MCAO) was established by middle cerebral artery occlusion/reperfusion. One-week of acupuncture was performed during the acute phase of ischemic stroke. The neurological function and brain tissue integrity were evaluated. Mitochondrial function (intracellular ATP level and the activity of mitochondrial respiratory chain complex I) and the level of NADH oxidase (NOX) were detected by enzymatic chemistry. Next, the potential molecular mechanisms were explored by western blotting, fluorescence quantitative PCR and immunohistochemistry method.Key findings(1) Acupuncture treatment for MCAO/R rats showed a significant improvement in the infarcted tissue accompanied by functional recovery in Zea-Longa score and balance beam score outcomes, motor function performances. (2) Acupuncture increased the levels of ATP and mitochondrial respiratory chain complex I, decreased the NOX levels in cerebral ischemia established by suture-occluded method. (3) Acupuncture reduced the necrosis dissolution of neuronal cells and meningeal edema, while promoting angiogenesis. (4) Quantitative immunohistochemical staining results showed acupuncture can increase the expression of AMPK, p-AMPK and the mitochondrial transcription factor PGC-1α, NRF2, TFAM and uncoupling protein 2 (UCP2). Meanwhile, acupuncture treatment up-regulated the expression of the corresponding protein. (5) Subsequently, acupuncture enhanced AMPK phosphorylation as well as the expression of PGC-1α, NRF2, TFAM and UCP2, implicated in mitochondrial synthesis and cellular apoptosis. (6) Finally, injections of AMPK antagonists and activators confirmed AMPK as a therapeutic target for the anti-nerve damage effects of acupuncture.SignificanceAcupuncture intervention relieved ischemic stroke progression in MCAO rats by promoting energy metabolism and mitochondrial biogenesis in the brain and alleviating neuronal apoptosis, which was mediated by eliciting AMPK/PGC-1α axis, among them AMPK is a therapeutic target.

Irisin, A Fascinating and Multifunctional Protein: Implication for Health

BACKGROUND: Fibronectin type III domain-containing protein 5 (FNDC5), or also known as irisin, has been identified for two decades but almost completely disregarded for 10 years. It is present in skeletal muscle, heart, and brain, and in reaction to exercise can transform white adipose tissue into brown. Since then, irisin has gained a lot of attention for its potencies in treating metabolic disorders. In this review article, the potential future of irisin especially on metabolism and aging process will be discussed.CONTENT: Sedentary lifestyle is acknowledged as risk factor for type 2 diabetes mellitus, obesity, immune system issues, asthma, and neurological or heart illness. Irisin is secreted by muscle cells when exercising, produced after the proteolytic cleavage of FNDC5 protein. Irisin has positive impacts on maintaining physiological balance including reducing inflammation, keeping the bone homeostasis, as well as influencing metabolic processes and the neurological system function. Due to these many and advantageous characteristics, irisin could be a possible choice for preventing and managing disorders associated with modern society, and finding the agents to increase irisin can be beneficial.SUMMARY: Irisin offers a fresh potential basis for kinesitherapy and shows promise as a therapeutic target due to its various biological activities. Irisin pathway can be activated through dietary changes, the use of natural substances and drugs and can interact with this signalling pathway which involved peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) and uncoupling protein mRNA 1 (UCP1) to resolve obesity and its metabolic comorbidities.KEYWORDS: irisin, FNDC5, exercise, inflammation, obesity, nervous system

Cholesterol 25-hydroxylase prevents type 2 diabetes mellitus induced cardiomyopathy by alleviating cardiac lipotoxicity

ObjectivesDiabetic cardiomyopathy (DCM) is the leading cause of mortality in type 2 diabetes mellitus (T2DM) patients, with its underlying mechanisms still elusive. This study aims to investigate the role of cholesterol-25-monooxygenase (CH25H) in T2DM induced cardiomyopathy. MethodsHigh fat diet combined with streptozotocin (HFD/STZ) were used to establish a T2DM model. CH25H and its product 25-hydroxycholesterol (25HC) were detected in the hearts of T2DM model. Gain- or loss-of-function of CH25H were performed by receiving AAV9-cTNT-CH25H or CH25H knockout (CH25H−/−) mice with HFD/STZ treatment. Cardiac function was evaluated using echocardiography, and cardiac tissues were collected for immunoblot analysis, histological assessment and quantitative polymerase chain reaction (qPCR). Mitochondrial morphology and function were evaluated using transmission electron microscopy (TEM) and Seahorse XF Cell Mito Stress Test Kit. RNA-sequence analysis was performed to determine the molecular changes associated with CH25H deletion. ResultsCH25H and 25HC were significantly decreased in the hearts of T2DM mice. CH25H−/− mice treated with HFD/STZ exhibited impaired mitochondrial function and structure, increased lipid accumulation, and aggregated cardiac dysfunction. Conversely, T2DM mice receiving AAV9-CH25H displayed cardioprotective effects. Mechanistically, RNA sequencing and qPCR analysis revealed that CH25H deficiency decreased peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and its target gene expression. Additionally, administration of ZLN005, a potent PGC-1α activator, partially protected against high glucose and palmitic acid induced mitochondria dysfunction and lipid accumulation in vitro. ConclusionOur study provides compelling evidence supporting the protective role of CH25H in T2DM-induced cardiomyopathy. Furthermore, the regulation of PGC-1α may be intricately involved in this cardioprotective process.

Dietary purple potato supplement attenuates DSS-induced colitis in mice: impact on mitochondrial function

Inflammatory bowel disease (IBD) is a condition characterized by disrupted intestinal barrier function, abnormal immune response, and mucosal structure loss. This study evaluated the beneficial role of purple potato (PP) supplementation against IBD symptoms using a murine model of dextran sulfate sodium (DSS)-induced colitis, and further explored the underlying mechanisms. Six-week-old C57BL/6J male mice were randomized into two groups and fed a standard rodent diet with or without 10% PP powder for 7 weeks. At the 5th week of dietary supplements, mice in each group were further divided into two subgroups and were either induced with or without 2.5% DSS induction for 7 days, followed by 7 days of recovery. Data showed that PP supplementation ameliorated the disease activity index in DSS-treated mice and reversed the colonic structure loss, mucosal damage, macrophage infiltration, and pro-inflammatory cytokine secretion induced by DSS in the colonic tissue. PP supplementation also restored the levels of tight junction proteins and caudal type homeobox 2 in DSS-treated mice. Furthermore, dietary PP enhanced peroxisome proliferator-activated receptor-γ coactivator-1α signaling pathway, mitochondrial biogenesis, mitochondrial proteostasis, and protein-folding capacity. In summary, dietary PP ameliorated DSS-induced colitis and improved gut structures and barrier function, which was associated with improved mitochondrial function. These results support further investigation of PP as a potential dietary intervention for IBD.

Remedial effects of tilapia skin peptides against dexamethasone-induced muscle atrophy in mice by modulation of AKT/FOXO3a and Sirt1/PGC-1α signaling pathways

Tilapia skin peptides (TSP) possess a range of physiological activities. This study aimed to explore the effects of TSP on Dexamethasone (DEX)-induced muscle atrophy. In vitro, C2C12 myotube myotube diameter and expression levels of the muscle-specific E3 ubiquitin ligases F-box only protein 32 (Atrogin-1) and muscle ring finger protein 1 (MuRF1) challenged with DEX were reversed by TSP. In vivo, DEX was injected subcutaneously to build muscle atrophy model mice. TSP enhanced grip strength, running distance, body lean muscle content, cross-sectional area of the gastrocnemius and tibialis anterior muscles of DEX-induced mice. Moreover, TSP inhibited the expression levels of Atrogin-1 and MuRF1. Mechanically, TSP improved DEX-induced muscle atrophy by regulating the Protein Kinase B α (AKT)/Forkhead box O3 protein (FOXO3a), Sirtuin 1 (Sirt1)/peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) signaling pathway, and downstream factors such as nuclear respiratory factor (NRF)1/2 and mitochondrial transcription factor A (TFAM).

Yo-Yo Dieting Delays Male Drosophila melanogaster Aging Through Enhanced Mitochondrial Function, Relative to Sustained High-Calorie Diet Feeding.

Weight regain subsequent to weight reduction resulting from dietary interventions represents a prevalent phenomenon recognized as "Yo-yo dieting." However, the impact of prolonged Yo-yo dieting on health, especially in relation to the aging process, remains poorly understood. This study aimed to investigate the influence of Yo-yo dieting on the aging process in male Drosophila melanogaster that have been exposed to a high-calorie (HC) diet. Fruit flies were fed with either a consistent HC diet or an alternating regimen of HC and low-calorie diets every 3 days (referred to as "Yo-yo dieting") for a total of 24 days. Biochemical assays were utilized to quantify levels of oxidative stress and activities of the mitochondrial respiratory chain complexes. The frozen section staining method was employed to assess the presence of lipid droplets, reactive oxygen species, cellular viability, and mitochondrial abundance in tissues. Additionally, we examined the expression of key regulators involved in mitochondrial dynamics and biogenic signaling pathways. Yo-yo dieting resulted in an extension of the fruit flies' lifespan, concomitant with reduced body weight, decreased body protein content, and lower triglyceride levels compared to continuous a HC diet feeding. Furthermore, Yo-yo dieting ameliorated impairments in motility and intestinal barrier function. Importantly, it improved mitochondrial function and upregulated the expression of essential mitochondrial fusion proteins, namely mitofusin 1 and mitofusin 2, optic atrophy 1, and peroxisome proliferator-activated receptor-γ coactivator-1α. Therefore, the practice of Yo-yo dieting extends the lifespan of fruit flies by modulating mitochondrial dynamics and the associated biogenic signaling pathways.

Dysregulation of mitochondrial dynamics mediated aortic perivascular adipose tissue-associated vascular reactivity impairment under excessive fructose intake

Excessive fructose intake presents the major risk factor for metabolic cardiovascular disease. Perivascular adipose tissue (PVAT) is a metabolic tissue and possesses a paracrine function in regulating aortic reactivity. However, whether and how PVAT alters vascular function under fructose overconsumption remains largely unknown. In this study, male Sprague-Dawley rats (8 weeks old) were fed a 60% high fructose diet (HFD) for 12 weeks. Fasting blood sugar, insulin, and triglycerides were significantly increased by HFD intake. Plasma adiponectin was significantly enhanced in the HFD group. The expression of uncoupling protein 1 (UCP1) and mitochondrial mass were reduced in the aortic PVAT of the HFD group. Concurrently, the expression of peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) and mitochondrial transcription factor A (TFAM) were suppressed. Furthermore, decreased fusion proteins (OPA1, MFN1, and MFN2) were accompanied by increased fission proteins (FIS1 and phospho-DRP1). Notably, the upregulated α-smooth muscle actin (α-SMA) and osteocalcin in the PVAT were concurrent with the impaired reactivity of aortic contraction and relaxation. Coenzyme Q10 (Q, 10 mg/100 mL, 4 weeks) effectively reversed the aforementioned events induced by HFD. Together, these results suggested that the dysregulation of mitochondrial dynamics mediated HFD-triggered PVAT whitening to impair aortic reactivity. Fortunately, coenzyme Q10 treatment reversed HFD-induced PVAT whitening and aortic reactivity.

Oleuropein-Rich Jasminum Grandiflorum Flower Extract Regulates the LKB1-PGC-1α Axis Related to the Attenuation of Hepatocellular Lipid Dysmetabolism.

Diets() rich in fat are a major() cause() of metabolic disease(), and nutritional() food has been widely() used() to counteract the metabolic disorders such() as obesity() and fatty() liver(). The present study investigated the effects of oleuropein-enriched extract() from Jasminum grandiflorum L. flowers (OLE-JGF) in high-fat diet() (HFD)-fed mice and oleic acid() (OA)-treated AML-12 cells. Treatment() of HFD-fed mice with 0.6% OLE-JGF for 8 weeks significantly reduced body and liver() weights, as well as attenuating lipid dysmetabolism and hepatic steatosis. OLE-JGF administration() prominently suppressed the mRNA expressions() of monocyte chemoattractant protein()-1 (MCP-1) and cluster of differentiation 68 (CD68), and it also downregulated acetyl-CoA carboxylase (ACC) and fatty() acid() synthase (FAS) as well as sterol-regulatory-element()-binding protein() (SREBP-1c) in the liver(). Meanwhile, mitochondrial DNA and uncoupling protein() 2 (UCP2) were upregulated along with the increased expression() of mitochondrial biogenic promoters including liver() kinase B1 (LKB1), peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), nuclear() factor()-erythroid-derived 2-like 2 (Nrf2), and mitochondrial transcription factor() A (Tfam), but did not change AMP-activated protein() kinase (AMPK) in liver(). The lipid droplets were decreased significantly after treatment() with 80 μM oleuropein for 24 h in OA-induced AML-12 cells. Furthermore, oleuropein significantly inhibited ACC mRNA expression() and upregulated LKB1, PGC-1α, and Tfam mRNA levels, as well as increasing the binding level of LKB1 to PGC-1α promoter in OA-induced cells. These findings indicate() that OLE-JGF reduces hepatic lipid deposition in HFD-fed mice, as well as the fact that OA-induced liver() cells may be partly() attributed to upregulation of the LKB1-PGC-1α axis, which mediates hepatic lipogenesis and mitochondrial biogenesis. Our study provides a scientific() basis() for the benefits and potential() use() of the J. grandiflorum flower as a food supplement() for the prevention() and treatment() of metabolic disease().

Songorine ameliorates LPS-induced sepsis cardiomyopathy by Wnt/β-catenin signaling pathway-mediated mitochondrial biosynthesis.

Septic cardiomyopathy (SCM) is manifested by impairment of cardiac contractile function with myocardial mitochondrial dysregulation. Natural product, songorine (SGR), a diterpenoid alkaloid derived from the lateral root of Aconitum carmichaeli, has been reported for the treatment of heart failure. Here, the protective role of SGR in heart injury of SCM was investigated and its underlying action of mechanism was explored. Firstly, the mouse and cardiomyocytes (H9C2 cell) SCM model induced by LPS were established to evaluate the therapeutic effect of SGR. The in vivo results exhibited that SGR rescued the survival rate of SCM mice, restored the loss of ejection fraction (EF) and fractional shortening (FS), and reduced left ventricular systolic diameter and left ventricular diastole diameter (LVIDs, LVIDd) by echocardiography. SGR improved the mitochondrial biosynthesis and myocardial fiber structure and arranged them neatly by transmission electron microscope (TEM). Further, SGR inhibited inflammatory targets myeloperoxidase (MPO) and tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and plasminogen activator inhibitor-1 (PAI-1). And SGR activated the mitochondrial biosynthesis-related peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), β-catenin, and matrix metallopeptidase 2 (MMP2) proteins. Meanwhile, the in vitro results showed that SGR promoted the increased the myocardial H9C2 cell viability, and mitochondrial biosynthesis and structure. SGR also blocked the inflammatory factors and reversed PGC-1α, β-catenin, and MMP2 in vitro, while SGR alleviated the myocardial cell apoptosis via flow cytometry. The findings indicate that SGR mitigates sepsis-caused myocardial damage by Wnt/β-catenin signaling pathway-mediated mitochondrial biosynthesis. SGR may be a promising candidate for treatment of SCM.

Empagliflozin ameliorates diabetic cardiomyopathy probably via activating AMPK/PGC-1α and inhibiting the RhoA/ROCK pathway.

Diabetic cardiomyopathy (DCM) increases the risk of hospitalization for heart failure (HF) and mortality in patients with diabetes mellitus. However, no specific therapy to delay the progression of DCM has been identified. Mitochondrial dysfunction, oxidative stress, inflammation, and calcium handling imbalance play a crucial role in the pathological processes of DCM, ultimately leading to cardiomyocyte apoptosis and cardiac dysfunctions. Empagliflozin, a novel glucose-lowering agent, has been confirmed to reduce the risk of hospitalization for HF in diabetic patients. Nevertheless, the molecular mechanisms by which this agent provides cardioprotection remain unclear. To investigate the effects of empagliflozin on high glucose (HG)-induced oxidative stress and cardiomyocyte apoptosis and the underlying molecular mechanism. Twelve-week-old db/db mice and primary cardiomyocytes from neonatal rats stimulated with HG (30 mmol/L) were separately employed as in vivo and in vitro models. Echocardiography was used to evaluate cardiac function. Flow cytometry and TdT-mediated dUTP-biotin nick end labeling staining were used to assess apoptosis in myocardial cells. Mitochondrial function was assessed by cellular ATP levels and changes in mitochondrial membrane potential. Furthermore, intracellular reactive oxygen species production and superoxide dismutase activity were analyzed. Real-time quantitative PCR was used to analyze Bax and Bcl-2 mRNA expression. Western blot analysis was used to measure the phosphorylation of AMP-activated protein kinase (AMPK) and myosin phosphatase target subunit 1 (MYPT1), as well as the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and active caspase-3 protein levels. In the in vivo experiment, db/db mice developed DCM. However, the treatment of db/db mice with empagliflozin (10 mg/kg/d) for 8 wk substantially enhanced cardiac function and significantly reduced myocardial apoptosis, accompanied by an increase in the phosphorylation of AMPK and PGC-1α protein levels, as well as a decrease in the phosphorylation of MYPT1 in the heart. In the in vitro experiment, the findings indicate that treatment of cardiomyocytes with empagliflozin (10 μM) or fasudil (FA) (a ROCK inhibitor, 100 μM) or overexpression of PGC-1α significantly attenuated HG-induced mitochondrial injury, oxidative stress, and cardiomyocyte apoptosis. However, the above effects were partly reversed by the addition of compound C (CC). In cells exposed to HG, empagliflozin treatment increased the protein levels of p-AMPK and PGC-1α protein while decreasing phosphorylated MYPT1 levels, and these changes were mitigated by the addition of CC. Adding FA and overexpressing PGC-1α in cells exposed to HG substantially increased PGC-1α protein levels. In addition, no sodium-glucose cotransporter (SGLT)2 protein expression was detected in cardiomyocytes. Empagliflozin partially achieves anti-oxidative stress and anti-apoptotic effects on cardiomyocytes under HG conditions by activating AMPK/PGC-1α and suppressing of the RhoA/ROCK pathway independent of SGLT2.

SR-18292 Induces Fetal Hemoglobin Synthesis and Reduces Disease Pathology in Sickle Cell Mice

Sickle cell disease (SCD) is a commonly inherited blood disorder, which affects millions around the world. Reactivation of fetal hemoglobin (HbF) synthesis in adult erythroid cells can diminish the severity of many clinical features of the disease. Up-regulation of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) has been shown to induce HbF levels in human primary erythroid progenitor CD34 + cells. Here we reported the in vitro and in vivo effects of a small molecular compound, SR-18292, on HbF induction via modulating PGC-1α. To determine whether SR-18292 can induce HbF in human CD34 + cells, we performed RT-qPCR, flow cytometry, and western blot to measure the mRNA and protein levels of PGC-1α and γ-globin. We found that mRNA levels of PGC-1α and γ-globin were significantly increased in cells treated with SR-18292 while β-globin mRNA levels were unaffected. Protein levels of γ-globin and the ratio of F-cells were increased in treated cells. Erythroid cellular differentiation markers (CD71/CD235a) and terminal differentiation markers (CD49d/CD233) were used to examine the differentiation status. There was no significant difference in the population of CD71 +CD235a + cells among all groups. However, SR-18292 treatment increased the percentage of CD49d -CD233 + cells at 5 or 7.5 μM. These results suggest that SR-18292 at higher concentrations can promote erythroid terminal differentiation. To evaluate whether the HbF induction by SR-18292 can reduce the SCD disease pathology in SCD mice or not, we intraperitoneally administered SR-18292 to SCD mice. HbF induction was determined by flow cytometric analysis using an anti-HbF antibody. And it was shown that the HbF-high cell population was induced in SCD mice after 4 weeks of treatment. And we used transferrin receptor CD71 and erythroid-specific marker Ter119 to determine whether SR-18292 could affect erythroid differentiation. There was no significant difference in the CD71 +Ter119 + population after 4 weeks of SR-18192 treatment compared with untreated animals. The mRNA levels of γ-globin and PGC-1α were increased in treated mice. And the increase of PGC-1α and γ-globin protein levels were confirmed by western blot. Reticulocyte is a sign of premature RBC destruction (hemolysis), and the SCD mice usually have high reticulocyte counts (>50%). We measured the reticulocyte in the peripheral blood of SR-18292 treated and untreated SCD mice by flow-cytometric analyses and found that reticulocyte was significantly reduced in SR-18292 treated animals (from 55% to 20%) after 4 weeks of treatment. Complete blood cell counts (CBC) showed that SR-18292 treated mice had slightly elevated numbers of red blood cells (RBCs) and more hemoglobin, but lower counts of white blood cells, lymphocytes, and neutrophils. In addition, the RBC distribution width (RDW) was significantly reduced after SR-18292 treatment, indicating that the size of circulating RBCs was more uniform in treated mice. In addition, erythroid cell morphology was evaluated by blood smears with Wright-Giemsa stain. The number of sickled RBCs were reduced in SCD mice treated with SR-18292 for 4 weeks. This is consistent with our observation that RDW was reduced in SCD mice treated with SR-18292. Furthermore, SR-18292 treated mice had a statistically significant reduction in spleen size and weight in contrast to the spleens of untreated SCD mice. The indices of RBCs were improved in accompany with reduced hemolysis and a higher fraction of circulating mature erythrocytes in treated SCD mice. There were no observable adverse effects on other hematopoietic cell lineages. We also performed single-cell RNA-seqs in human CD34 + cells treated with SR-18292 and found that some known HbF repressors (such as BCL11A and ZBTB7A) were decreased in treated groups. Besides that, there were many differentially expressed genes (DEGs), which might be novel HbF regulators. We are verifying those DEGs genes by qPCR and using CRISPR/cas9 to examine their functions in globin regulation. In summary, our findings suggest that SR-18292 might be a promising therapeutic agent to treat SCD and modulating PGC-1α activity or the signaling pathways that it regulates might benefit therapeutically patients with SCD.

Engineered mesenchymal stem cell-derived small extracellular vesicles for diabetic retinopathy therapy through HIF-1α/EZH2/PGC-1α pathway

Diabetic retinopathy (DR) is a leading cause of blindness worldwide with limited treatment options. Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) hold promise as a cell-free therapy for retinal diseases. In this study, we present evidence that the intravitreal injection of MSC-sEVs improved retinal function and alleviated retinal apoptosis, inflammation, and angiogenesis in both db/db mice and streptozotocin-induced diabetic rats. Mechanistically, hyperglycemia-induced activation of hypoxia-inducible factor-1α (HIF-1α) inhibited the tripartite motif 21 (TRIM21)-mediated ubiquitination and degradation of enhancer of zeste homologue 2 (EZH2), ultimately resulting in the downregulation of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) through EZH2-induced methylation modification. The presence of miR-5068 and miR-10228 in MSC-sEVs targeted the HIF-1α/EZH2/PGC-1α pathway. The blockade of miR-5068 and miR-10228 abolished the retinal therapeutic effects of MSC-sEVs. Additionally, we engineered MSC-sEVs with elevated levels of miR-5068 and miR-10228 to enhance retinal repair efficiency. Together, our findings provide novel insights into the mechanism underlying DR progress and highlight the potential of MSC-sEVs, especially engineered MSC-sEVs, as a therapeutic option for DR.

Serum ve Plazma Örneklerinde İrisin Seviyesini Ölçmeden Önce Aprotinin İlave Etmek Gerekir mi?

Irisin is a myokine with 112 amino acids and its blood concentration is regulated by peroxisome proliferator-activated receptor-γ coactivator1-α (PGC1-α). It is released into circulation from skeletal muscle tissue after a photolytic cleavage of extracellular domain of Fibronectin type III domain-containing protein 5 (FNDC5), a type I integral membrane protein. Aprotinin is a polyvalent serin protease inhibitor. It is added to sample solutions such as serum, plasma or tissue extracts in order to inhibit serine proteases found in the sample medium. Hence, degradation of the proteins to be measured can be prevented. This study has been carried out to obtain a preliminary data if any irisin loss could be seen in the serum samples which are kept at -80°C for a long duration. For this purpose, blood samples of 10 men and 10 women volunteers aged between 25-40 has been used. Aprotinin has been added to the plasma and the serum samples have been kept at -80°C for 3 months. At the end of 3 months, irisin levels of the samples with and without aprotinin have been determined by ELISA. Statistical analysis has shown no difference between the plasma samples with or without aprotinin (p=0.525). However, a significant decrease between the serum samples with and without aprotinin (p=0.009). In conclusion, with the results of this study, no net decision could have been achieved to add aprotinin to the samples for irisin determination with ELISA in plasma and serum kept at -80°C for about 3 months.

The neuroprotective effects of FG-4592, a hypoxia-inducible factor-prolyl hydroxylase inhibitor, against oxidative stress induced by alpha-synuclein in N2a cells

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra. The pathological hallmark of PD is the appearance of intraneuronal cytoplasmic α-synuclein (α-Syn) aggregation, called Lewy bodies. α-Syn aggregation is deeply involved in the pathogenesis of PD. Oxidative stress is also associated with the progression of PD. In the present study, to investigate whether a hypoxia-inducible factor (HIF)-prolyl hydroxylase (PH) inhibitor, FG-4592 (also called roxadustat), has neuroprotective effects against α-Syn-induced neurotoxicity, we employed a novel α-Syn stably expressing cell line (named α-Syn-N2a cells) utilizing a piggyBac transposon system. In α-Syn-N2a cells, oxidative stress and cell death were induced by α-Syn, and FG-4592 showed significant protection against this neurotoxicity. However, FG-4592 did not affect α-Syn protein levels. FG-4592 triggered heme oxygenase-1 (HO-1) expression downstream of HIF-1α in a concentration-dependent manner. In addition, FG-4592 decreased the production of reactive oxygen species possibly via the activation of HO-1 and subsequently suppressed α-Syn-induced neurotoxicity. Moreover, FG-4592 regulated mitochondrial biogenesis and respiration via the induction of the peroxisome proliferator-activated receptor-γ coactivator-1α. As FG-4592 has various neuroprotective effects against α-Syn and is involved in drug repositioning, it may have novel therapeutic potential for PD.

Peroxisome Proliferator-Activated Receptor-γ Coactivator-1α in the Spotlight with Multiple Sclerosis.

Peroxisome Proliferator-Activated Receptor-γ Coactivator-1α in the Spotlight with Multiple Sclerosis.

Molecular control of endurance training adaptation in male mouse skeletal muscle

Skeletal muscle has an enormous plastic potential to adapt to various external and internal perturbations. Although morphological changes in endurance-trained muscles are well described, the molecular underpinnings of training adaptation are poorly understood. We therefore aimed to elucidate the molecular signature of muscles of trained male mice and unravel the training status-dependent responses to an acute bout of exercise. Our results reveal that, even though at baseline an unexpectedly low number of genes define the trained muscle, training status substantially affects the transcriptional response to an acute challenge, both quantitatively and qualitatively, in part associated with epigenetic modifications. Finally, transiently activated factors such as the peroxisome proliferator-activated receptor-γ coactivator 1α are indispensable for normal training adaptation. Together, these results provide a molecular framework of the temporal and training status-dependent exercise response that underpins muscle plasticity in training.

PGC-1α inhibits M2 macrophage polarization and alleviates liver fibrosis following hepatic ischemia reperfusion injury

Oxidative stress can induce inflammation, promoting macrophage polarization and liver fibrosis following hepatic ischemia-reperfusion (I/R). Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) has anti-oxidant and anti-inflammatory activity. However, how PGC-1α regulates macrophage polarization following hepatic I/R remains largely unknown. Male C57BL/6 wild-type mice were pre-treated with vehicle or trichostatin A (TSA) for 2 days and subjected to surgical induction of I/R. Liver injury and fibrosis in individual mice were examined longitudinally and the expression levels of IL-6, STAT3, M2-type macrophage markers, Collagen I and α-SMA in the liver of mice were analyzed by immunohistochemistry, RT-qPCR and Western blot. The potential interaction of PGC-1α with phosphorylated NF-kBp65 was determined by immunoprecipitation. The impacts of PGC-1α deficiency in hepatocytes on their IL-6 production and macrophage polarization were tested in a Transwell co-culture system. Moreover, the M2-type macrophage polarization and liver fibrosis were examined in hepatocyte-specific PGC-1α knockout mice and AAV8-mediated PGC-1α over-expressing mice following liver I/R. The down-regulated PGC-1α expression by I/R was negatively correlated with IL-6 levels in the liver of I/R mice and PGC-1α deficiency enhanced IL-6 expression, STAT3 activation and M2-type macrophage polarization in the I/R mice, which were abrogated by TSA treatment. In addition, PGC-1α directly interacted with phosphorylated NF-kBp65 in I/R livers. Hepatocyte-specific PGC-1α deficiency increased IL-6 production and promoted macrophage polarization toward M2 type when co-culture. More importantly, administration with AAV8-PGC-1α rescued the I/R-induced liver fibrosis by inhibiting the IL-6/JAK2/STAT3 signaling and M2-type macrophage polarization in the liver. These results suggest that PGC-1α may alleviate the I/R-induced liver fibrosis by attenuating the IL-6/JAK2/STAT3 signaling to limit M2-type macrophage polarization. PGC-1α may be a therapeutic target for the treatment of liver fibrosis.

Structural and functional impairments of skeletal muscle in patients with postacute sequelae of SARS-CoV-2 infection.

Following acute coronavirus disease 2019 (COVID-19), a substantial proportion of patients showed symptoms and sequelae for several months, namely the postacute sequelae of COVID-19 (PASC) syndrome. Major phenomena are exercise intolerance, muscle weakness, and fatigue. We aimed to investigate the physiopathology of exercise intolerance in patients with PASC syndrome by structural and functional analyses of skeletal muscle. At least 3 mo after infection, nonhospitalized patients with PASC (n = 11, age: 54 ± 11 yr; PASC) and patients without long-term symptoms (n = 12, age: 49 ± 9 yr; CTRL) visited the laboratory on four nonconsecutive days. Spirometry, lung diffusion capacity, and quality of life were assessed at rest. A cardiopulmonary incremental exercise test was performed. Oxygen consumption (V̇o2) kinetics were determined by moderate-intensity exercises. Muscle oxidative capacity (k) was assessed by near-infrared spectroscopy. Histochemical analysis, O2 flux (JO2) by high-resolution respirometry, and quantification of key molecular markers of mitochondrial biogenesis and dynamics were performed in vastus lateralis biopsies. Pulmonary and cardiac functions were within normal range in all patients. V̇o2peak was lower in PASC than CTRL (24.7 ± 5.0 vs. 32.9 ± 7.4 mL·min-1·kg-1, respectively, P < 0.05). V̇o2 kinetics was slower in PASC than CTRL (41 ± 12 vs. 30 ± 9 s-1, P < 0.05). k was lower in PASC than CTRL (1.54 ± 0.49 vs. 2.07 ± 0.51 min-1, P < 0.05). Citrate synthase, peroxisome proliferator-activated receptor-γ coactivator (PGC)1α, and JO2 for mitochondrial complex II were significantly lower in PASC vs. CTRL (all P values <0.05). In our cohort of patients with PASC, we showed limited exercise tolerance mainly due to "peripheral" determinants. Substantial reductions were observed for biomarkers of mitochondrial function, content, and biogenesis. PASC syndrome, therefore, appears to negatively impact skeletal muscle function, although the disease is a heterogeneous condition.NEW & NOTEWORTHY Several months after mild acute SARS-CoV-2 infection, a substantial proportion of patients present persisting, and often debilitating, symptoms and sequelae. These patients show reduced quality of life due to exercise intolerance, muscle weakness, and fatigue. The present study supports the hypothesis that "peripheral" impairments at skeletal muscle level, namely, reduced mitochondrial function and markers of mitochondrial biogenesis, are major determinants of exercise intolerance and fatigue, "central" phenomena at respiratory, and cardiac level being less relevant.

Downregulation of PGC-1α during cisplatin-induced muscle atrophy in murine skeletal muscle

This study aimed to investigate the effects of cisplatin on adenosine triphosphate (ATP) levels, expressions of genes related to mitochondrial oxidative phosphorylation (OXPHOS), and the factors related to mitochondrial biosynthesis in skeletal muscle. Systemic cisplatin administration decreased skeletal muscle mass, skeletal muscle strength, and endurance. The mitochondrial DNA /nuclear DNA ratio was also reduced after treatment with cisplatin. Moreover, among the factors related to mitochondrial biogenesis and function, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) was significantly downregulated in the cisplatin-treated group. Downregulation of PGC-1α in the skeletal muscle may contribute to muscle weakness during cisplatin-induced muscle atrophy.

Quercetin Attenuates Atherosclerosis via Modulating Apelin Signaling Pathway Based on Plasma Metabolomics.

To interpret the pharmacology of quercetin in treatment of atherosclerosis (AS). Fourteen apolipoprotein E-deficient (ApoE-/-) mice were divided into 2 groups by a random number table: an AS model (ApoE-/-) group and a quercetin treatment group (7 in each). Seven age-matched C57 mice were used as controls (n=7). Quercetin [20 mg/(kg·d)] was administered to the quercetin group intragastrically for 8 weeks for pharmacodynamic evaluation. Besides morphological observation, the distribution of CD11b, F4/80, sirtuin 1 (Sirt1) and P21 was assayed by immunohistochemistry and immunofluorescence to evaluate macrophage infiltration and tissue senescence. Ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MSC/MS) was performed to study the pharmacology of quercetin against AS. Then, simultaneous administration of an apelin receptor antagonist (ML221) with quercetin was conducted to verify the possible targets of quercetin. Key proteins in apelin signaling pathway, such as angiotensin domain type 1 receptor-associated proteins (APJ), AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), tissue plasminogen activator (TPA), uncoupling protein 1 (UCP1) and angiotensin II receptor 1 (AT1R), were assayed by Western blot. Quercetin administration decreased lipid deposition in arterial lumen and improved the morphology of ApoE-/- aortas in vivo. Quercetin decreased the densities of CD11b, F4/80 and P21 in the aorta and increased the level of serum apelin and the densities of APJ and Sirt1 in the aorta in ApoE-/- mice (all P<0.05). Plasma metabolite profiling identified 118 differential metabolites and showed that quercetin affected mainly glycerophospholipids and fatty acyls. Bioinformatics analysis suggested that the apelin signaling pathway was one of the main pathways. Quercetin treatment increased the protein expressions of APJ, AMPK, PGC-1α, TPA and UCP1, while decreased the AT1R level (all P<0.05). After the apelin pathway was blocked by ML221, the effect of quercetin was abated significantly, confirming that quercetin attenuated AS by modulating the apelin signaling pathway (all P<0.05). Quercetin alleviated AS lesions by up-regulation the apelin signaling pathway.