PGC-1α Protein Research Articles

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.

Abstract 15747: AMPK Cysteine Oxidation by SOD3-Derived H 2 O 2 Mediates Exercise-Induced Restoration of Skeletal Muscle Angiogenesis in Type2 Diabetes

Background: Exercise restores decreased capillary density in skeletal muscle (SKM) (capillary rarefaction) in type2 diabetes (T2D) that has eNOS uncoupling/excess O 2 - , which is required for treatment of diabetic peripheral vascular disease (PAD) via unknown mechanisms. AMP-activated protein kinase (AMPK) is a key angiogenic/metabolic kinase mainly regulated by phosphorylation and is required for baseline, but not exercise-induced capillary density in SKM under healthy conditions. AMPK senses H 2 O 2 signal to increase its activity via oxidative modification of Cys299/304 in vitro. In addition, extracellular SOD (SOD3) that catalyzes the dismutation of O 2 - to H 2 O 2 is increased in response to exercise. However, the role of AMPK and SOD3 in exercise-induced SKM angiogenesis in T2D has not been reported. Oxidation of Cysteine residues to generate cysteine sulfenic acid (Cys-OH) is a key event in H 2 O 2 -mediated signaling. Results: Here we show that reduced CD31+ capillary density in SKM of high fat diet-induced T2D mice was restored (2.4-fold) by voluntary wheel exercise training (2 weeks) with enhanced SOD3 activity (224%) and extracellular H 2 O 2 levels (3.2-fold). Of note, exercise in T2D mice increased AMPK activity (by p-ACC) via inducing CysOH formation of AMPK (3.6-fold), but not p-AMPK induction, which was inhibited by SOD3 -/- /T2D mice that reduced exercise-induced H 2 O 2 . To demonstrate functional significance of AMPK Cys oxidation, we generated CRISPR/Cas9-genome editing “redox-dead” AMPK-Cys299/304Ala (AMPK-C/A) knock-in (KI) mutant mice and found that AMPK-C/A KI mice showed significant inhibition of exercise-induced angiogenesis (44%) via reducing angiogenic PGC1α and VEGF protein expression in SKM of T2D mice. In vitro, C2C12 skeletal muscles overexpressing SOD3 treated with palmitate (mimic T2D with exercise) induced AMPK-CysOH formation and VEGF secretion. Its conditioned media promoted angiogenic responses such as EC migration (1.8-fold) and tube formation (1.7-fold), which was inhibited by C2C12 cells overexpressing AMPK C/A mutant. Conclusion: Novel exercise-induced AMPK CysOH formation at Cys299/304 restores angiogenesis in SKM of T2D via SOD3-mediated H 2 O 2 , which may contribute to revascularization in diabetic PAD.

Phenotype and energy metabolism differ between osteoarthritic chondrocytes from male compared to female patients: Implications for sexual dimorphism in osteoarthritis development?

ObjectivesThe prevalence and severity of knee osteoarthritis (OA) are greater in females than males. The purpose of this study was to determine whether there is an underlying difference in the biology of OA chondrocytes between males and females. MethodsChondrocytes were obtained following knee arthroplasty from male and female patients with primary OA. Phenotype marker expression, glucose and fat consumption, and rates of glycolysis and oxidative phosphorylation were compared between females and males. RNAi was used to determine the consequences of differential expression of Sry-box transcription factor 9 (SOX9) and PGC1α between males and females. ResultsOA chondrocytes from male donors showed elevated RNA and protein levels of SOX9, elevated COL2A1 protein synthesis, higher glucose consumption, and higher usage of glycolysis compared to females. OA chondrocytes from females had higher PGC1α protein levels, higher fat consumption, and higher oxidative energy metabolism than males. Knockdown of SOX9 reduced expression of COL2A1 to a greater extent in male OA chondrocytes than females whereas knockdown of PGC1α reduced COL2A1 expression in females but not males. Expression of ACAN and the glycolytic enzyme PGK1 was also reduced in males but not females following SOX9 knockdown. ConclusionsOA chondrocyte phenotype and energy metabolism differ between males and females. Our results indicate transcriptional control of COL2A1 differs between the two. Differences in chondrocyte biology between males and females imply the underlying mechanisms involved in OA may also differ, highlighting the need to consider sex and gender when investigating pathogenesis and potential treatments for OA.

Postconditioning with D-limonene exerts neuroprotection in rats via enhancing mitochondrial activity

Abstract Objectives The key component of neuroprotection after cerebral ischemia–reperfusion (I–R) injury is mitochondrial improvement. By focusing on the function of mitochondrial biogenesis and ATP-sensitive potassium (mK–ATP) channels and inflammatory responses, the current study assessed the neuroprotective potentials of lemon essential oil, D-limonene (LIM), in rats with cerebral I–R injury. Methods In order to simulate cerebral I–R injury, Sprague Dawley rats (n=72) were subjected to a two h local ischemia induced by middle cerebral artery blockage, followed by a 24 h reperfusion period. Five minutes before starting reperfusion, rats were intraperitoneally given LIM at doses of 10 or 100 mg/kg. Cerebral infarct volume was assessed by triphenyl-tetrazolium chloride staining, brain activity by behavioral tests and mitochondrial function/biogenesis, as well as proinflammatory cytokines by fluorometry, immunoblotting and other related techniques. Results When compared to the untreated control group, the administration of LIM substantially and dose-dependently decreased cerebral infarct volumes and neurological deficits (p<0.01). I–R injury-induced alterations in mitochondrial membrane depolarization, mitochondrial reactive oxygen species (mitoROS), and superoxide dismutase (mnSOD), as well as inflammatory cytokines TNF-α, IL-6 and IL-1β, were all significantly reversed after treatment with LIM 100 mg/kg (p<0.01). Additionally, this dose of LIM increased the expression of mitochondrial biogenesis proteins PGC-1α, TFAM, and NRF1. Interestingly, blockage of mK–ATP channels by 5-hydoxydecanoate diminished the effects of LIM on cerebral positive endpoints, cytokines production, and mitochondrial function/biogenesis. Conclusions Thus, the strong neuroprotective effects of LIM-postconditioning were mediated by an increase in mK–ATP channel activity, which improved mitochondrial biogenesis and suppressed inflammatory responses.

SIRT1-dependent mitochondrial biogenesis supports therapeutic effects of vidarabine against rotenone-induced neural cell injury

Parkinson's disease (PD) is the second most common neurodegenerative disease in the world, which is distinguished by the loss of dopaminergic (DA) neurons in the substantia nigra and the formation of intraneuronal. Numerous studies showed that the damage and dysfunction of mitochondria may play key roles in DA neuronal loss. Thus, it is necessary to seek therapeutic measures for PD targeting mitochondrial function and biogenesis. In this study, through screening the purchased compound library, we found that marine derived vidarabine had significant neuroprotective effects against rotenone (ROT) induced SH-SY5Y cell injury. Further studies indicated that vidarabine pretreatment significantly protected ROT-treated SH-SY5Y cells from toxicity by preserving mitochondrial morphology, improving mitochondrial function, and reducing cell apoptosis. Vidarabine also reduced the oxidative stress and increased the expression levels of PGC-1α, NRF1, and TFAM proteins, which was accompanied by the increased mitochondrial biogenesis. However, the neuroprotective effects of vidarabine were counteracted in the presence of SIRT1-specific inhibitor Ex-527. Besides, vidarabine treatment attenuated the weight loss, alleviated the motor deficits and inhibited the neuronal injury in the MPTP induced mouse model. Thus, vidarabine may exert neuroprotective effects via a mechanism involving specific connections between the SIRT1-dependent mitochondrial biogenesis and its antioxidant capacity, suggesting that vidarabine has potential to be developed into a novel therapeutic agent for PD.

Kaempferol Alleviates Mitochondrial Damage by Reducing Mitochondrial Reactive Oxygen Species Production in Lipopolysaccharide-Induced Prostate Organoids.

Common prostate diseases such as prostatitis and benign prostatic hyperplasia (BPH) have a high incidence at any age. Cellular stresses, such as reactive oxygen species (ROS) and chronic inflammation, are implicated in prostate enlargement and cancer progression and development. Kaempferol is a flavonoid found in abundance in various plants, including broccoli and spinach, and has been reported to exhibit positive biological activities, such as antioxidant and anti-inflammatory properties. In the present study, we introduced prostate organoids to investigate the protective effects of kaempferol against various cellular stresses. The levels of COX-2, iNOS, p-IκB, a pro-inflammatory cytokine, and ROS were increased by LPS treatment but reversed by kaempferol treatment. Kaempferol activated the nuclear factor erythroid 2-related factor 2(Nrf2)-related pathway and enhanced the mitochondrial quality control proteins PGC-1α, PINK1, Parkin, and Beclin. The increase in mitochondrial ROS and oxygen consumption induced by LPS was stabilized by kaempferol treatment. First, our study used prostate organoids as a novel evaluation platform. Secondly, it was demonstrated that kaempferol could alleviate the mitochondrial damage in LPS-induced induced prostate organoids by reducing the production of mitochondrial ROS.

Effects of myostatin gene knockout on white fat browning and related gene expression in type 2 diabetic mice.

Myostatin (Mstn) plays an important role in adipocyte growth, differentiation and metabolism, leading to the development of obesity. We aimed to explore the effect of Mstn on white fat browning in a mouse model of type 2 diabetes mellitus (T2DM). Twelve wild-type (WT), 12 heterozygous (Mstn(+/-)) and 12 homozygous (Mstn(-/-)) male mice were randomly divided into 6 groups: WT, Mstn(+/-), Mstn(-/-), WT+DM, Mstn(+/-)+DM, and Mstn(-/-)+DM. The first 3 groups were fed normal chow, while the last 3 were fed high-fat diet and administered streptozotocin to generate T2DM. Subsequently, body mass, length, and white and brown fat masses were measured, after which Lee's index, white-brown ratio and fat index were calculated. The serum free fatty acid (FFA) levels were detected using enzyme-linked immunosorbent assay (ELISA). Hematoxylin and eosin (H&E) staining was used to analyze white and brown fat cell morphology. The relative expression levels of peroxisome proliferator-activated receptor-gamma (PPARγ), peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α), uncoupling protein 1 (UCP1), and cluster of differentiation 137 (CD137) protein were determined with western blotting. The Mstn(-/-) group displayed higher levels of PPARγ, PGC-1α and CD137 proteins in white and brown fat compared to the WT and Mstn(+/-) groups, while the expression level of UCP1 protein in the Mstn(-/-) group was higher than in the WT group. The expression levels of PPARγ, PGC-1α, UCP1, and CD137 proteins in the WT+DM group were lower than in the WT group. Moreover, PPARγ, PGC-1α, UCP1, and CD137 proteins were more highly expressed in the Mstn(-/-)+DM group compared to the WT+DM and Mstn(+/-)+DM groups. The Mstn gene inhibition antagonizes obesity phenotypes, such as white fat accumulation and lipid metabolism derangement caused by T2DM, thus promoting white fat browning.

Anoikis resistance and immune escape mediated by Epstein-Barr virus-encoded latent membrane protein 1-induced stabilization of PGC-1α promotes invasion and metastasis of nasopharyngeal carcinoma

BackgroundEpstein-Barr virus (EBV) is the first discovered human tumor virus that is associated with a variety of malignancies of both lymphoid and epithelial origin including nasopharyngeal carcinoma (NPC). The EBV-encoded latent membrane protein 1 (LMP1) has been well-defined as a potent oncogenic protein, which is intimately correlated with NPC pathogenesis. Anoikis is considered to be a physiological barrier to metastasis, and avoiding anoikis is a major hallmark of metastasis. However, the role of LMP1 in anoikis-resistance and metastasis of NPC has not been fully identified.MethodsTrypan blue staining, colony formation assay, flow cytometry, and TUNEL staining, as well as the detection of apoptosis and anoikis resistance‐related markers was applied to evaluate the anoikis-resistant capability of NPC cells cultured in ultra-low adhesion condition. Co-immunoprecipitation (Co-IP) experiment was performed to determine the interaction among LMP1, PRMT1 and PGC-1α. Ex vivo ubiquitination assay was used to detect the ubiquitination level of PGC-1α. Anoikis- resistant LMP1-positive NPC cell lines were established and applied for the xenograft and metastatic animal experiments.ResultsOur current findings reveal the role of LMP1-stabilized peroxisome proliferator activated receptor coactivator-1a (PGC-1α) in anoikis resistance and immune escape to support the invasion and metastasis of NPC. Mechanistically, LMP1 enhances PGC-1α protein stability by promoting the interaction between arginine methyltransferase 1 (PRMT1) and PGC-1α to elevate the methylation modification of PGC-1α, thus endowing NPC cells with anoikis-resistance. Meanwhile, PGC-1α mediates the immune escape induced by LMP1 by coactivating with STAT3 to transcriptionally up-regulate PD-L1 expression.ConclusionOur work provides insights into how virus-encoded proteins recruit and interact with host regulatory elements to facilitate the malignant progression of NPC. Therefore, targeting PGC-1α or PRMT1-PGC-1α interaction might be exploited for therapeutic gain for EBV-associated malignancies.

Low-dose atorvastatin protects skeletal muscle mitochondria in high-fat diet-fed mice with mitochondrial autophagy inhibition and fusion enhancement

Despite the great clinical benefits of statins in cardiovascular diseases, their widespread use may lead to adverse muscle reactions associated with mitochondrial dysfunction. Some studies have demonstrated that statins provide substantial improvement to skeletal muscle health in mice. Our previous study found that oral treatment with atorvastatin (Ator, 3 mg/kg) protected myocardial mitochondria in high-fat diet (HFD)-fed mice. Therefore, this study aimed to explore the influence of low-dose Ator (3 mg/kg) on mitochondria in skeletal muscle under cholesterol overload. Male C57BL/6J mice were fed a HFD for 18 weeks and orally administered Ator (3 mg/kg) during the last 12 weeks. Ator treatment had no effects on elevated serum cholesterol and glucose levels in HFD-fed mice. Serum creatine kinase levels and the cross-sectional area of muscle cells were not affected by HFD feeding or Ator treatment. Increased expression of PINK1-LC3 II (activated mitophagy), MFN2 (fusion), and PGC-1α (biogenesis) proteins was induced in the skeletal muscles of HFD-fed mice. Treatment with Ator inhibited PINK1 and LC3 II protein expression, but further promoted MFN1, MFN2, and OPA1 expression. The impairments in mitochondrial quality and morphology in HFD-fed mice were attenuated by treatment with Ator. Furthermore, Ator treatment enhanced glucose oxidation capacity and restored ATP production in the skeletal muscles of HFD-fed mice. The study reveals that low-dose Ator has a protective effect on muscle mitochondria in mice, likely through inhibiting mitophagy and enhancing mitochondrial fusion. This suggests that skeletal muscle mitochondria may be one of low-dose Ator-mediated protective targets.

Comparison of Eight Weeks of Moderate-intensity Continuous Training (MICT) and High-intensity Intermittent Training (HIIT) with Sodium Citrate Supplementation on PGC-1α Expression

Introduction: Sports activity increases the expression of PGC-1α, the regulatory factor of mitochondrial biogenesis. This study aimed to investigate the effect of eight weeks of Moderate-intensity Continuous Training (MICT) and High-intensity Intermittent Training (HIIT), along with sodium citrate supplementation, on PGC-1α expression in male Wistar rats. Method: Forty rats were placed in the following five groups: Control, MICT, MICT+sodium citrate, HIIT, and HIIT+sodium citrate. The continuous training group ran for eight weeks and five sessions per week with an average intensity of 70% of the maximum running speed for 15-30 minutes. The interval training group ran for 12 minutes with an intensity range of 50% and 90%. In addition to exercise, the exercise+supplement groups received 15 mmol/l sodium citrate supplement daily. The expression of PGC-1α in the soleus muscle was measured by the western blot method. Data analysis was done using one-way analysis of variance and Tukey's post hoc test. Results: The PGC-1α protein expression increased in both the training groups and the training+supplement groups compared to the control group (P=0.001). Furthermore, adding sodium citrate could significantly increase the PGC-1α expression in the MICTgroup+supplement compared to the MICT group (P=0.005). However, the HIIT had a higher effect on PGC-1α expression than the MICT group. Conclusion: Despite the effectiveness of both training methods, sodium citrate supplementation before HIIT could have more synergistic effects in increasing the expression of PGC-1α.

The Parkinson’s disease-associated mutation LRRK2 G2385R alters mitochondrial biogenesis via the PGC-1α-TFAM pathway

Mutations in the Leucine-rich repeat protein kinase 2 (LRRK2) gene are the most frequent cause of familial Parkinson’s disease (PD). Although LRRK2 has been extensively studied, the pathogenic mechanism of the LRRK2 G2385R mutation, which is most common in Asian populations, especially in the Chinese Han population, remains unclear. In this study, we demonstrated that the LRRK2 G2385R mutation in HEK293T cells led to a reduction in cellular PGC-1α protein expression and inhibition of mitochondrial biogenesis through the PGC-1α-TFAM pathway. This resulted in a decrease in mitochondrial genome expression, which in turn impaired the normal electron transfer process of the oxidative phosphorylation respiratory chain, leading to mitochondrial dysfunction and onset of apoptosis. The mitochondrial dysfunction and apoptosis caused by the LRRK2 G2385R mutation were significantly alleviated by antioxidant Idebenone, which provides a theoretical basis for the subsequent development of precise treatment specifically for PD patients with LRRK2 G2385R mutation. Further validation of our findings in neurons and animal models are necessary.

Altered expression, but small contribution, of the histone demethylase KDM6A in obstructive uropathy in mice.

Epigenetic processes have emerged as important modulators of kidney health and disease. Here, we studied the role of KDM6A (a histone demethylase that escapes X-chromosome inactivation) in kidney tubule epithelial cells. We initially observed an increase in tubule cell Kdm6a mRNA in male mice with unilateral ureteral obstruction (UUO). However, tubule cell knockout of KDM6A had relatively minor consequences, characterized by a small reduction in apoptosis, increase in inflammation and downregulation of the peroxisome proliferator-activated receptor (PPAR) signaling pathway. In proximal tubule lineage HK-2 cells, KDM6A knockdown decreased PPARγ coactivator-1α (PGC-1α) protein levels and mRNA levels of the encoding gene, PPARGC1A. Tubule cell Kdm6a mRNA levels were approximately 2-fold higher in female mice than in male mice, both under sham and UUO conditions. However, kidney fibrosis after UUO was similar in both sexes. The findings demonstrate Kdm6a to be a dynamically regulated gene in the kidney tubule, varying in expression levels by sex and in response to injury. Despite the context-dependent variation in Kdm6a expression, knockout of tubule cell KDM6A has subtle (albeit non-negligible) effects in the adult kidney, at least in males.

Polysaccharide from Ziyang Selenium-Enriched Green Tea Prevents Obesity and Promotes Adipose Thermogenesis via Modulating the Gut Microbiota.

The objective of the current study was to explore the potential mechanism of Ziyang selenium-enriched green tea polysaccharide (Se-GTP) against obesity. The results showed that Se-GTP significantly alleviated obesity and related metabolic disorders caused by high-fat diet (HFD) in mice. 16S rRNA gene sequencing results revealed that Se-GTP improved gut microbiota disturbance of obese mice and facilitated proliferation of probiotics such as Bacteroides, Bifidobacterium, Lactobacillus, and Akkermansia. In addition, the colonic content of succinate, a product of microbial metabolite in connection with adipocyte thermogenesis, was significantly enhanced by Se-GTP treatment. Therefore, Se-GTP facilitated brown adipose tissue (BAT) thermogenesis and inguinal white adipose tissue (iWAT) browning in obese mice, which could be revealed by increased expressions of thermogenic marker proteins UCP1, PGC-1α, and CIDEA in BAT and iWAT. Interestingly, Se-GTP intervention also observably increased the content of M2-like macrophages in iWAT of obese mice. To summarize, the results of this study are the first to show that Se-GTP can stimulate the browning of iWAT and BAT thermogenesis to counteract obesity, which may be pertinent with the alteration of gut microbiota in obese mice.

Protective effect of Xinmai'an tablets via mediation of the AMPK/SIRT1/PGC-1α signaling pathway on myocardial ischemia-reperfusion injury in rats

BackgroundXinmai'an tablets are a compound Chinese medicine comprising six traditional Chinese medicines that have been clinically applied to treat cardiovascular diseases such as premature ventricular contractions for many years. However, pharmacological effects and underlying mechanisms of Xinmai'an tablet in protecting against myocardial ischemia-reperfusion injury (MIRI) were barely ever studied. PurposeTo investigate the cardioprotective properties of Xinmai'an tablet against MIRI and the underlying molecular mechanism in rats. MethodsWe initially established the UHPLC-QTRAP-MS/MS analysis method to ensure the controllable quality of Xinmai'an tablet. We further identified the cardioprotective effects of Xinmai'an tablet against MIRI using TTC staining, hematoxylin and eosin, echocardiography, the transmission electron microscope analysis, biochemical analysis, and ELISA. We then investigated whether the safeguarding effect of Xinmai'an tablet on MIRI model rats was related to AMPK/SIRT1/PGC-1α pathway via western blotting. ResultsXinmai'an tablet decreased myocardial infarct size; ameliorated cardiac function; alleviated myocardial and mitochondrial damage; and suppressed oxidative stress injury, vascular endothelial damage, and apoptosis response in MIRI model rats. Mechanistically, our results showed that Xinmai'an tablet can dramatically activate the AMPK/SIRT1/PGC-1αpathway and subsequently diminish mitochondrial oxidative stress damage. This was evidenced by increased ATP, Na+-K+-ATPase, and Ca2+-Mg2+-ATPase levels, upregulation of GLUT4, p-AMPK, SIRT1, and PGC-1α protein levels; and reduced GLUT1 protein level. ConclusionTo the knowledge of the author of this article, this study is the first report of Xinmai'an tablet attenuating MIRI, potentially associated with the activation of the AMPK/SIRT1/PGC-1α pathway and subsequent reduction of mitochondrial oxidative stress damage. These findings reveal a novel pharmacological effect and mechanism of action of Xinmai'an tablet and highlight a promising therapeutic drug for ischemic cardiovascular diseases.

Effects of carnosic acid on mitochondrial biogenesis and insulin sensitivity in 3T3-L1 adipocytes are through induction of PGC-1α and ubiquitination of PARIS by parkin

The PGC-1α plays a vital role in regulating mitochondrial biogenesis and insulin sensitivity. This study investigated the role of PGC-1α in preventing the effects of carnosic acid (CA) against TNF-α-suppressed mitochondrial biogenesis and insulin signaling. Exposure of 3T3-L1 adipocytes to TNF-α decreased the proteins of PGC-1α and nuclear respiratory factor 1 (NRF1). However, pretreatment with CA improved this change. Additionally, CA led to increases in parkin protein and decreases in PARIS protein. Using immunoprecipitation assay, the protein interaction between PARIS and ubiquitin was increased and that between PARIS and parkin was decreased after CA treatment. Parkin siRNA blocked the effects of CA on PARIS, PGC-1α, and NRF1 proteins. PGC-1α siRNA abolished the capacity of CA to reverse the TNF-α-inhibited insulin signaling and membrane GLUT4 protein translocation. Therefore, CA attenuates the TNF-α induced impairment of mitochondrial biogenesis and glucose uptake through activation of PGC-1α via ubiquitination of PARIS by parkin.

Scorpion venom heat-resistant peptide alleviates mitochondrial dynamics imbalance induced by PM2.5 exposure by downregulating the PGC-1α/SIRT3 signaling pathway.

Epidemiological inquiry reveals that neuroinflammation and mitochondrial dysfunction caused by PM2.5 exposure are associated with Alzheimer's disease. Nevertheless, the molecular mechanisms of mitochondrial dynamics and neuroinflammation induced by PM2.5 exposure remain elusive. In this study, our objective was to explore the impact of PM2.5 on mitochondrial dynamics and neuroinflammation, while also examining the reparative potential of scorpion venom heat-resistant synthetic peptide (SVHRSP). Western blot and quantitative reverse transcription polymerase chain reaction (RT-qPCR) were employed to ascertain the protein and gene levels of IL-1β, IL-6, and TNF-α in BV2 cells. The concentration of IL-6 in the supernatant of the BV2 cell culture was measured by enzyme-linked immunosorbent assay. For the assessment of mitochondrial homeostasis, western blot, RT-qPCR, and cellular immunohistochemistry methods were utilized to investigate the protein and gene levels of DRP1 and MFN-2 in HT22 cells. In the context of signal pathway analyses, western blot, RT-qPCR, and immunofluorescence techniques were employed to detect the protein and gene expressions of PGC-1α and SIRT3 in HT22 cells, respectively. Following the transfection with siPGC-1αRNA, downstream proteins of PGC-1α/SIRT3 pathway in HT22 cells were investigated by Western blot and RT-qPCR. The experimental findings demonstrated that exposure to PM2.5 exacerbated neuroinflammation, resulting in elevated levels of IL-1β, IL-6, and TNF-α. Furthermore, it perturbed mitochondrial dynamics, as evidenced by increased DRP1 expression and decreased MFN-2 expression. Additionally, dysfunction was observed in the PGC-1α/SIRT3 signal pathway. However, intervention with SVHRSP ameliorated the cellular damage induced by PM2.5 exposure. SVHRSP alleviated neuroinflammation and mitochondrial dynamics imbalance induced by PM2.5 exposure by downregulating the PGC-1α/SIRT3 signaling pathway.

Notch signaling regulates a metabolic switch through inhibiting PGC-1α and mitochondrial biogenesis in dedifferentiated liposarcoma.

Human dedifferentiated liposarcoma (DDLPS) is a rare but lethal cancer with no driver mutations being identified, hampering the development of targeted therapies. We and others recently reported that constitutive activation of Notch signaling through overexpression of the Notch1 intracellular domain (NICDOE) in murine adipocytes leads to tumors resembling human DDLPS. However, the mechanisms underlying the oncogenic functions of Notch activation in DDLPS remains unclear. Here, we show that Notch signaling is activated in a subset of human DDLPS and correlates with poor prognosis and expression of MDM2, a defining marker of DDLPS. Metabolic analyses reveal that murine NICDOE DDLPS cells exhibit markedly reduced mitochondrial respiration and increased glycolysis, mimicking the Warburg effect. This metabolic switch is associated with diminished expression of peroxisome proliferator-activated receptor gamma coactivator 1α (Ppargc1a, encoding PGC-1α protein), a master regulator of mitochondrial biogenesis. Genetic ablation of the NICDOE cassette rescues the expression of PGC-1α and mitochondrial respiration. Similarly, overexpression of PGC-1α is sufficient to rescue mitochondria biogenesis, inhibit the growth and promote adipogenic differentiation of DDLPS cells. Together, these data demonstrate that Notch activation inhibits PGC-1α to suppress mitochondrial biogenesis and drive a metabolic switch in DDLPS.

Alpha Hope, via Molecular Hydrogen and Pyrroloquinoline Quinone, Dose-Dependently Increases Nrf2 and PGC-1α Levels in C2C12 Myoblasts

Alpha Hope is a dietary supplement containing pyrroloquinoline quinone and elemental magnesium, which produces molecular hydrogen (H2 gas) when dissolved in water. We determined the impact of Alpha Hope on Nrf-2, peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α), and citrate synthase (CS) activity in C2C12 myoblasts. Alpha Hope was titrated to three concentrations of pyrroloquinoline quinone (PQQ) (10 nM, 100 nM, 1000 nM) and treated on C2C12 for 48 h. Nrf-2 and PGC-1α levels were measured using Western blot analysis. CS activity was measured according to previously described methods. Treatment significantly increased Nrf-2 and PGC-1α protein levels in C2C12 myoblasts, with no change for CS. For Nrf-2, values for both the 100 nM (p = 0.046) and 1000 nM (p = 0.011) concentrations were higher than control. For PGC-1α, values for both the 100 nM (p = 0.039) and 1000 nM (p = 0.017) concentrations were higher than control. In a small human pilot study, subjects consumed the Alpha Hope product daily for four weeks, with no adverse effects, with some subjects noted as “responders” to treatment. Alpha Hope can significantly increase both Nrf-2 and PGC-1α in a concentration-dependent manner. Healthy men and women who ingest the product daily can do so without adverse effects.

Antioxidative Role of Heterophagy, Autophagy, and Mitophagy in the Retina and Their Association with the Age-Related Macular Degeneration (AMD) Etiopathogenesis.

Age-related macular degeneration (AMD), an oxidative stress-linked neurodegenerative disease, leads to irreversible damage of the central retina and severe visual impairment. Advanced age and the long-standing influence of oxidative stress and oxidative cellular damage play crucial roles in AMD etiopathogenesis. Many authors emphasize the role of heterophagy, autophagy, and mitophagy in maintaining homeostasis in the retina. Relevantly modifying the activity of both macroautophagy and mitophagy pathways represents one of the new therapeutic strategies in AMD. Our review provides an overview of the antioxidative roles of heterophagy, autophagy, and mitophagy and presents associations between dysregulations of these molecular mechanisms and AMD etiopathogenesis. The authors performed an extensive analysis of the literature, employing PubMed and Google Scholar, complying with the 2013-2023 period, and using the following keywords: age-related macular degeneration, RPE cells, reactive oxygen species, oxidative stress, heterophagy, autophagy, and mitophagy. Heterophagy, autophagy, and mitophagy play antioxidative roles in the retina; however, they become sluggish and dysregulated with age and contribute to AMD development and progression. In the retina, antioxidative roles also play in RPE cells, NFE2L2 and PGC-1α proteins, NFE2L2/PGC-1α/ARE signaling cascade, Nrf2 factor, p62/SQSTM1/Keap1-Nrf2/ARE pathway, circulating miRNAs, and Yttrium oxide nanoparticles performed experimentally in animal studies.

Metformin inhibits methylglyoxal-induced retinal pigment epithelial cell death and retinopathy via AMPK-dependent mechanisms: Reversing mitochondrial dysfunction and upregulating glyoxalase 1

Diabetic retinopathy (DR) is a major cause of blindness in adult, and the accumulation of advanced glycation end products (AGEs) is a major pathologic event in DR. Methylglyoxal (MGO), a highly reactive dicarbonyl compound, is a precursor of AGEs. Although the therapeutic potential of metformin for retinopathy disorders has recently been elucidated, possibly through AMPK activation, it remains unknown how metformin directly affects the MGO-induced stress response in retinal pigment epithelial cells. Therefore, in this study, we compared the effects of metformin and the AMPK activator A769662 on MGO-induced DR in mice, as well as evaluated cytotoxicity, mitochondrial dynamic changes and dysfunction in ARPE-19 cells. We found MGO can induce mitochondrial ROS production and mitochondrial membrane potential loss, but reduce cytosolic ROS level in ARPE-19 cells. Although these effects of MGO can be reversed by both metformin and A769662, we demonstrated that reduction of mitochondrial ROS production rather than restoration of cytosolic ROS level contributes to cell protective effects of metformin and A769662. Moreover, MGO inhibits AMPK activity, reduces LC3II accumulation, and suppresses protein and gene expressions of MFN1, PGC-1α and TFAM, leading to mitochondrial fission, inhibition of mitochondrial biogenesis and autophagy. In contrast, these events of MGO were reversed by metformin in an AMPK-dependent manner as evidenced by the effects of compound C and AMPK silencing. In addition, we observed an AMPK-dependent upregulation of glyoxalase 1, a ubiquitous cellular enzyme that participates in the detoxification of MGO. In intravitreal drug-treated mice, we found that AMPK activators can reverse the MGO-induced cotton wool spots, macular edema and retinal damage. Functional, histological and optical coherence tomography analysis support the protective actions of both agents against MGO-elicited retinal damage. Metformin and A769662 via AMPK activation exert a strong protection against MGO-induced retinal pigment epithelial cell death and retinopathy. Therefore, metformin and AMPK activator can be therapeutic agents for DR.