Malvidin promotes PGC-1α/Nrf2 signaling to attenuate the inflammatory response and restore mitochondrial activity in septic acute kidney injury.

Acute kidney injury (AKI) in sepsis is a vital and dangerous organ failure caused by an infection-induced dysregulation of the host reaction. Malvidin possesses significant anti-inflammatory and antioxidant bioactivities. This study explored the critical roles of malvidin in sepsis AKI and the crosstalk among mitochondrial function, nucleotide-binding oligomerization-like receptor 3 (NLRP3) inflammasome and nuclear factor erythroid 2 (Nrf2) signaling pathway. First, C57BL/6 mice were administered lipopolysaccharide intraperitoneally for 6 h to create an AKI model of sepsis. Hematoxylin-eosin staining and serum biomarker assays showed that malvidin protected from AKI in sepsis. Real-time fluorescence quantitative polymerase chain reaction analysis revealed that malvidin was able to inhibit inflammatory cytokines and mediators. Western blot assays indicated that malvidin suppressed NLRP3 inflammasome activation and enhanced antioxidant properties. Additionally, human renal tubular epithelial cells were stimulated by lipopolysaccharide/adenosine triphosphate to establish an NLRP3 inflammasome activation model in vitro, and in line with findings in vivo, malvidin significantly inhibited NLRP3 inflammasome activation. Furthermore, our data indicate that malvidin restored mitochondrial quality and function, reduced reactive oxygen species production, increased mitochondrial membrane potential, enhanced mitochondrial DNA copy number, and promoted peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) nuclear translocation. Moreover, inhibitor blockade assays indicated that both PGC-1α and Nrf2 affected the inhibition of the NLRP3 inflammasome by malvidin. Finally, immunoprecipitation assays showed that malvidin promoted PGC-1α and Nrf2 interactions. Overall, malvidin alleviated lipopolysaccharide-induced sepsis AKI, improved mitochondrial function and mitochondrial biogenesis, and inhibited the NLRP3 inflammasome through the PGC-1α/Nrf2 signaling pathway, suggesting that malvidin might translate into clinical applications for sepsis AKI therapy.

Alpha-lipoic acid attenuates silica-induced pulmonary fibrosis by improving mitochondrial function via AMPK/PGC1α pathway activation in C57BL/6J mice.

Silicosis is characterized by pulmonary interstitial fibrosis that arises as a result of chronic exposure to silica. The few available treatments only delay its progression. As α-lipoic acid (ALA) has been shown to have various beneficial effects, including mitoprotective, antioxidant, and anti-inflammatory effects, we hypothesized that it may exhibit therapeutic effects in pulmonary fibrosis. Therefore, in the present study, we used a murine model of silicosis to investigate whether supplementation with exogenous ALA could attenuate silica-induced pulmonary fibrosis by improving mitochondrial function. ALA was administered to the model mice via continuous intragastric administration for 28 days, and then the antioxidant and mitoprotective effects of ALA were evaluated. The results showed that ALA decreased the production of reactive oxygen species, protected mitochondria from silica-induced dysfunction, and inhibited extracellular matrix deposition. ALA also decreased hyperglycemia and hyperlipidemia. Activation of the mitochondrial AMPK/PGC1α pathway might be responsible for these ALA-mediated anti-fibrotic effects. Exogenous ALA blocked oxidative stress by activating NRF2. Taken together, these findings demonstrate that exogenous ALA effectively prevents the progression of silicosis in a murine model, likely by stimulating mitochondrial biogenesis and endogenous antioxidant responses. Therefore, ALA can potentially delay the progression of silica-induced pulmonary fibrosis.

Intranasal 15d-PGJ2 ameliorates brain glucose hypometabolism via PPARγ-dependent activation of PGC-1α/GLUT4 signalling in APP/PS1 transgenic mice.

Targeting the common molecular mechanism of type 2 diabetes mellitus and Alzheimer's disease (AD), including dysregulation of glucose metabolism, insulin resistance, and neuroinflammation, might be an efficient treatment strategy for AD. Previous studies have shown that 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), an endogenous PPARγ agonist, has anti-inflammatory, insulin sensitizing and anti-diabetic effects. However, whether 15d-PGJ2 has beneficial effects on AD remains to be elucidated. In the present study, we found that intranasal administration of 15d-PGJ2 (300 ng/30 µL/day) for 3 months significantly inhibited Aß plaques, suppressed neuroinflammation, and attenuated cognitive deficits in APP/PS1 transgenic mice. Interestingly, 15d-PGJ2 treatment could increase brain glucose uptake, as detected by 18F-FDG microPET imaging, and co-localization of GLUT4 and NeuN in the hippocampus of APP/PS1 mice. Furthermore, 15d-PGJ2 markedly increased the expression of PPARγ and PGC-1α, upregulated GLUT4, and decreased the phosphorylation of IRS-1 (Ser616) in the hippocampus of APP/PS1 mice. Importantly, co-administration of a PPARγ antagonist GW9662 abrogated these protective effects of 15d-PGJ2. Collectively, intranasal 15d-PGJ2 conferred protective effects against AD by activating PPARγ-dependent PGC-1α/GLUT4 signalling. The PPARγ agonist 15d-PGJ2 might be a potential therapeutic drug for AD.

Brain-Derived Neurotrophic Factor Improves Impaired Fatty Acid Oxidation Via the Activation of Adenosine Monophosphate-Activated Protein Kinase-ɑ - Proliferator-Activated Receptor-r Coactivator-1ɑ Signaling in Skeletal Muscle of Mice With Heart Failure.

BACKGROUND: We recently reported that treatment with rhBDNF (recombinant human brain-derived neurotrophic factor) improved the reduced exercise capacity of mice with heart failure (HF) after myocardial infarction (MI). Since BDNF is reported to enhance fatty acid oxidation, we herein conducted an in vivo investigation to determine whether the improvement in exercise capacity is due to the enhancement of the fatty acid oxidation of skeletal muscle via the AMPKα-PGC1α (adenosine monophosphate-activated protein kinase-ɑ-proliferator-activated receptor-r coactivator-1ɑ) axis. METHODS: MI and sham operations were conducted in C57BL/6J mice. Two weeks postsurgery, we randomly divided the MI mice into groups treated with rhBDNF or vehicle for 2 weeks. AMPKα-PGC1α signaling and mitochondrial content in the skeletal muscle of the mice were evaluated by Western blotting and transmission electron microscopy. Fatty acid ß-oxidation was examined by high-resolution respirometry using permeabilized muscle fiber. BDNF-knockout mice were treated with 5-aminoimidazole-4-carboxamide-1-beta-d-riboruranoside, an activator of AMPK. RESULTS: The rhBDNF treatment significantly increased the expressions of phosphorylated AMPKα and PGC1α protein and the intermyofibrillar mitochondrial density in the MI mice. The lowered skeletal muscle mitochondrial fatty acid oxidation was significantly improved in the rhBDNF-treated MI mice. The reduced exercise capacity and mitochondrial dysfunction of the BDNF-knockout mice were improved by 5-aminoimidazole-4-carboxamide-1-beta-d-riboruranoside. CONCLUSIONS: Beneficial effects of BDNF on the exercise capacity of mice with HF are mediated through an enhancement of fatty acid oxidation via the activation of AMPKα-PGC1α in skeletal muscle. BDNF may become a therapeutic option to improve exercise capacity as an alternative or adjunct to exercise training.

Phosphocreatine Promotes Osteoblastic Activities in H2O2-Induced MC3T3-E1 Cells by Regulating SIRT1/FOXO1/PGC-1α Signaling Pathway.

BACKGROUND: Osteoporosis, characterized by bone loss, usually occurs with the increased bone resorption and decreased bone formation. H2O2-induced MC3T3-E1 cells are commonly used for the study of osteoblastic activities, which play a crucial role in bone formation. OBJECTIVE: This study aimed to investigate the effects of Phosphocreatine (PCr) on the osteoblastic activities in H2O2-induced MC3T3-E1 cells and elaborate on the possible molecular mechanism. METHODS: The Osteoprotegerin (OPG)/Receptor Activator of NF-κB Ligand (RANKL) ratio and osteogenic markers were detected to investigate the effects of PCr on osteoblastic activities, and the osteoblastic apoptosis was detected using Hochest staining. Moreover, oxidative stress, Adenosine Triphosphate (ATP) generation and the expression of Sirtuin 1 (SIRT1), Forkhead Box O 1 (FOXO1) and Peroxisome Proliferator-Activated Receptor Γ Coactivator-1α (PGC-1α) were also examined to uncover the possible molecular mechanism in H2O2-induced MC3T3-E1 cells. RESULT: The results showed that PCr promoted the osteoblastic differentiation by increasing the expression levels of osteogenic markers of Alkaline Phosphatase (ALP) and Runt-related transcription factor 2 (Runx2), as well as increased the OPG/RANKL ratio and suppressed the osteoblastic apoptosis in H2O2-induced MC3T3-E1 cells. Moreover, treatment with PCr suppressed reactive oxygen species (ROS) over-generation and promoted the ATP production as well as increased the PGC-1α, FOXO1 and SIRT1 protein expression levels in H2O2-induced MC3T3-E1 cells. CONCLUSION: PCr treatment could promote osteoblastic activities via suppressing oxidative stress and increasing the ATP generation in H2O2-induced MC3T3-E1 cells. In addition, the positive effects of PCr on osteoblasts might be regulated by SIRT1/FOXO1/ PGC-1α signaling pathway.

Melatonin alleviates angiotensin-II-induced cardiac hypertrophy via activating MICU1 pathway.

Mitochondrial calcium uptake 1 (MICU1) is a pivotal molecule in maintaining mitochondrial homeostasis under stress conditions. However, it is unclear whether MICU1 attenuates mitochondrial stress in angiotensin II (Ang-II)-induced cardiac hypertrophy or if it has a role in the function of melatonin. Here, small-interfering RNAs against MICU1 or adenovirus-based plasmids encoding MICU1 were delivered into left ventricles of mice or incubated with neonatal murine ventricular myocytes (NMVMs) for 48 h. MICU1 expression was depressed in hypertrophic myocardia and MICU1 knockdown aggravated Ang-II-induced cardiac hypertrophy in vivo and in vitro. In contrast, MICU1 upregulation decreased cardiomyocyte susceptibility to hypertrophic stress. Ang-II administration, particularly in NMVMs with MICU1 knockdown, led to significantly increased reactive oxygen species (ROS) overload, altered mitochondrial morphology, and suppressed mitochondrial function, all of which were reversed by MICU1 supplementation. Moreover, peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α)/MICU1 expression in hypertrophic myocardia increased with melatonin. Melatonin ameliorated excessive ROS generation, promoted mitochondrial function, and attenuated cardiac hypertrophy in control but not MICU1 knockdown NMVMs or mice. Collectively, our results demonstrate that MICU1 attenuates Ang-II-induced cardiac hypertrophy by inhibiting mitochondria-derived oxidative stress. MICU1 activation may be the mechanism underlying melatonin-induced protection against myocardial hypertrophy.

Perillyl Alcohol Mitigates Behavioural Changes and Limits Cell Death and Mitochondrial Changes in Unilateral 6-OHDA Lesion Model of Parkinson's Disease Through Alleviation of Oxidative Stress.

In this study, we aim to assess the phytomedicinal potential of perillyl alcohol (PA), a dietary monoterpenoid, in a unilateral 6-hydroxydopamine (6-OHDA) lesion rat model of Parkinson's disease (PD). We observed that PA supplementation alleviated behavioural abnormalities such as loss of coordination, reduced rearing and motor asymmetry in lesioned animals. We also observed that PA-treated animals exhibited reduced oxidative stress, DNA fragmentation and caspase 3 activity indicating alleviation of apoptotic cell death. We found reduced mRNA levels of pro-apoptotic regulator BAX and pro-inflammatory mediators IL18 and TNFα in PA-treated animals. Further, PA treatment successfully increased mRNA and protein levels of Bcl2, mitochondrial biogenesis regulator PGC1α and tyrosine hydroxylase (TH) in lesioned animals. We observed that PA treatment blocked BAX and Drp1 translocation to mitochondria, an event often associated with the inception of apoptosis. Further, 6-OHDA exposure reduced expression of electron transport chain complexes I and IV, thereby disturbing energy metabolism. Conversely, expression levels of both complexes were upregulated with PA treatment in lesioned rats. Finally, we found that protein levels of Nrf2, the transcription factor responsible for antioxidant gene expression, were markedly reduced in cytosolic and nuclear fraction on 6-OHDA exposure, and PA increased expression of Nrf2 in both fractions. We believe that our data hints towards PA having the ability to provide cytoprotection in a hemiparkinsonian rat model through alleviation of motor deficits, oxidative stress, mitochondrial dysfunction and apoptosis.

PGC-1α activator ZLN005 promotes maturation of cardiomyocytes derived from human embryonic stem cells.

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have great potential in biomedical applications. However, the immature state of cardiomyocytes obtained using existing protocols limits the application of hPSC-CMs. Unlike adult cardiac myocytes, hPSC-CMs generate ATP through an immature metabolic pathway-aerobic glycolysis, instead of mitochondrial oxidative phosphorylation (OXPHOS). Hence, metabolic switching is critical for functional maturation in hPSC-CMs. Peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) is a key regulator of mitochondrial biogenesis and metabolism, which may help promote cardiac maturation during development. In this study, we investigated the effects of PGC-1α and its activator ZLN005 on the maturation of human embryonic stem cell-derived cardiomyocyte (hESC-CM). hESC-CMs were generated using a chemically defined differentiation protocol and supplemented with either ZLN005 or DMSO (control) on differentiating days 10 to 12. Biological assays were then performed around day 30. ZLN005 treatment upregulated the expressions of PGC-1α and mitochondrial function-related genes in hESC-CMs and induced more mature energy metabolism compared with the control group. In addition, ZLN005 treatment increased cell sarcomere length, improved cell calcium handling, and enhanced intercellular connectivity. These findings support an effective approach to promote hESC-CM maturation, which is critical for the application of hESC-CM in disease modeling, drug screening, and engineering cardiac tissue.

Exendin-4 Improves Diabetic Kidney Disease in C57BL/6 Mice Independent of Brown Adipose Tissue Activation.

BACKGROUND: The role of exendin-4 in brown adipose tissue (BAT) activation was not very clear. This study is to verify the role of BAT involved in renal benefits of exendin-4 in diabetes mellitus (DM). METHODS: In vivo, C57BL/6 mice were randomly divided into nondiabetic (control) and diabetic groups (DM). The diabetic mice were randomized into a control group (DM-Con), BAT-excision group (DM+Exc), exendin-4-treated group (DM+E4), and BAT-excision plus exendin-4-treated group (DM+Exc+E4). The weight, blood glucose and lipids, 24 h urine albumin and 8-OH-dG, and renal fibrosis were analyzed. In vitro, we investigated the role of exendin-4 in the differentiation process of 3T3-L1 and brown preadipocytes and its effect on the rat mesangial cells induced by oleate. RESULTS: The expressions of UCP-1, PGC-1α, ATGL, and CD36 in BAT of DM mice were all downregulated, which could be upregulated by exendin-4 treatment with significant effects on ATGL and CD36. BAT-excision exacerbated high blood glucose (BG) with no significant effect on the serum lipid level. Exendin-4 significantly lowered the level of serum triglycerides (TG) and low-density lipoprotein- (LDL-) c, 24 h urine albumin, and 8-OH-dG; improved renal fibrosis and lipid accumulation; and activated renal AMP-activated protein kinase (AMPK) in diabetic mice regardless of BAT excision. In vitro, there was no significant effect of exendin-4 on brown or white adipogenesis. However, exendin-4 could improve lipid accumulation and myofibroblast-like phenotype transition of mesangial cells induced by oleate via activating the AMPK pathway. CONCLUSIONS: Exendin-4 could decrease the renal lipid deposit and improve diabetic nephropathy via activating the renal AMPK pathway independent of BAT activation.

Paeonol protects mitochondrial injury and prevents pulmonary vascular remodeling in hypoxia.

Mitochondrial injury of pulmonary artery smooth muscle cells (PASMCs) is an important stage in the development of pulmonary arterial hypertension (PAH). Recent studies revealed that Paeonol exerts anti-proliferative effects on vascular smooth muscle cells. However, whether Paeonol is directly involved in mitochondrial injury related to PAH remains unknown. Here, we found that hypoxia-induced mitochondrial injury in vivo was alleviated in the presence of Paeonol. Hypoxia mediated the mitochondrial injuries in PASMCs in vitro, including decreased ATP generation, morphological alterations, mitochondrial polarization and increased reactive oxygen species production, which were suppressed by Paeonol. Our results also indicated that the expression of peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) was regulated by Paeonol. Paeonol caused significant alterations in mitochondrion-dependent apoptosis through PGC-1α in PASMCs. Taken together, these results provide the first evidence confirming the protective effect of Paeonol in mediating mitochondrial injury under hypoxia and elucidating the necessary role of PGC-1α in the effects of Paeonol in inducing PASMC apoptosis.

Low-Intensity Exercise Suppresses CCAAT/Enhancer-Binding Protein δ/Myostatin Pathway Through Androgen Receptor in Muscle Cells.

BACKGROUND: Androgen production following exercise has been suggested to contribute anabolic actions of muscle. However, the underlying mechanisms of the androgen receptor (AR) in androgen's action are still unclear. OBJECTIVE: In the present study, we examined androgen/AR-mediated action in exercise, especially for the suppression of myostatin, a potent negative regulator of muscle mass. METHODS: To examine the effects of exercise, we employed low-intensity exercise in mice and electric pulse stimulation (EPS) in C2C12 myotubes. Androgen production by C2C12 myotubes was measured by enzyme-linked immunosorbent assay. To block the action of AR, we pretreated C2C12 myotubes with flutamide. Quantitative real-time polymerase chain reaction was used to determine the expression levels of proteolytic genes including CCAAT/enhancer-binding protein delta (C/EBPδ), myostatin and muscle E3 ubiquitin ligases, as well as myogenic genes such as myogenin and PGC1α. The activation of 5'-adenosine-activated protein kinase and STAT3 was determined by Western blot analysis. RESULTS: Both mRNA and protein levels of AR significantly increased in skeletal muscle of low-intensity exercised mice and C2C12 myotubes exposed to EPS. Production of testosterone and dihydrotestosterone from EPS-treated C2C12 myotubes was markedly increased. Of interest, we found that myostatin was clearly inhibited by EPS, and its inhibition was significantly abrogated when AR was blocked by flutamide. To test how AR suppresses myostatin, we examined the effects of EPS on C/EBPδ because the promoter region of myostatin has several C/EBP recognition sites. C/EBPδ expression was decreased by EPS, and this decrease was negated by flutamide. IL-6 and phospho-STAT3 (pSTAT3) expression, the downstream pathway of myostatin, were decreased by EPS and this was also reversed by flutamide. Similar downregulation of C/EBPδ, myostatin, and IL-6 was seen in skeletal muscle of low-intensity exercised mice. CONCLUSIONS: Muscle AR expression and androgen production were increased by exercise and EPS treatment. As a mechanistical insight, it is suggested that AR inhibited myostatin expression transcriptionally by C/EBPδ suppression, which negatively influences IL-6/pSTAT3 expression and consequently contributes to the prevention of muscle proteolysis during exercise.

Long-term liraglutide ameliorates nigrostriatal impairment via regulating AMPK/PGC-1a signaling in diabetic mice.

Growing evidence indicates links between type 2 diabetes and Parkinson's disease. The glucagon-like peptide 1 analogue, liraglutide, a commonly used anti-diabetic drug, has protective effects on neurons. The goal of this study was to determine whether long-term liraglutide treatment could reduce the risk of adult type 2 diabetic mice developing Parkinson's disease. Male diabetic db/db mice (12 weeks old) were injected daily with liraglutide (n = 8), or saline (n = 8), and non-diabetic m/m littermates (n = 6) were included as controls. Motor function was assessed every 4 weeks and all mice were sacrificed after 8 weeks of drug intervention for further analysis. The results revealed that long-term treatment of liraglutide protected the db/db mice against the motor function decay and the dopaminergic neuron loss. Liraglutide also restored the impaired AMP kinase (AMPK)/peroxisome proliferator-activated receptor-γ coactivator 1a (PGC-1a) signaling in the striatum of db/db mice. Further experiments in SH-SY5Y cells supported that AMPK is involved in the neuroprotective effect of liraglutide. In summary, long-term liraglutide ameliorated motor dysfunction and dopaminergic neuron impairment in type 2 diabetic mice, probably via enhancing AMPK/PGC-1a signaling.

Estrogen and voluntary exercise attenuate cardiometabolic syndrome and hepatic steatosis in ovariectomized rats fed a high-fat high-fructose diet.

The prevalence of cardiometabolic syndrome (CMS) is increased in women after menopause. While hormone replacement therapy has been prescribed to relieve several components of CMS in postmenopausal women, some aspects of cardiometabolic dysfunction cannot be completely restored. The present study examined the effectiveness of estrogen replacement alone and in combination with exercise by voluntary wheel running (VWR) for alleviating the risks of CMS, insulin-mediated skeletal muscle glucose transport, and hepatic fat accumulation in ovariectomized Sprague-Dawley rats fed a high-fat high-fructose diet (OHFFD). We compared a sham-operated group with OHFFD rats that were subdivided into a sedentary, estradiol replacement (E2), and E2 plus VWR for 12 wk. E2 prevented the development of insulin resistance in skeletal muscle glucose transport and decreased hepatic fat accumulation in OHFFD rats. Furthermore, E2 treatment decreased visceral fat mass and low-density lipoprotein (LDL)-cholesterol in OHFFD rats, while VWR further decreased LDL-cholesterol and increased the ratio of high-density lipoprotein-cholesterol to total cholesterol to a greater extent. Although E2 treatment alone did not reduce serum triglyceride levels in OHFFD rats, the combined intervention of E2 and VWR lowered serum triglycerides in E2-treated OHFFD rats. The addition of VWR to E2-treated OHFFD rats led to AMPK activation and upregulation of peroxisome proliferator-activated receptor-γ (PPARγ) coactivator-1α and PPARδ in skeletal muscle along with increased fatty acid oxidation and suppressed fatty acid synthesis in the liver. Collectively, our findings indicate that, to achieve greater health benefits, physical exercise is required for E2-treated individuals under ovarian hormone deprivation with high-energy consumption.

Resveratrol Reduces Oxidative Stress and Apoptosis in Podocytes via Sir2-Related Enzymes, Sirtuins1 (SIRT1)/Peroxisome Proliferator-Activated Receptor γ Co-Activator 1α (PGC-1α) Axis.

BACKGROUND PGC-1α can be activated by deacetylation reactions catalyzed by SIRT1. Resveratrol is currently known as a potent activator of SIRT1. However, it is unknown whether the renal-protective effect of resveratrol is further related to activation of the podocyte SIRT1/PGC-1α pathway. MATERIAL AND METHODS High glucose was used to stimulate mouse podocytes. Resveratrol and PGC-1α siRNA transfection were used to perform co-intervention treatments. The protein and mRNA expression levels of SIRT1, PGC-1α, NRF1, and TFAM were detect by immunofluorescence, Western blot analysis, and qRT-PCR in the podocytes, respectively. DCHF-DA and MitoSOX™ staining were used to monitor the total ROS and mitochondrial ROS levels, respectively. The specific activities of complexes I and III were measured using Complex I and III Assay Kits. Mitochondrial membrane potential and cell apoptosis were measured using JC-1 staining and Annexin V-FITC/PI double-staining, respectively. RESULTS We found that high-glucose stimulation results in time-dependent decreases in the expression of SIRT1, PGC-1α, and its downstream genes NRF1 and mitochondrial transcription factor A (TFAM) for mouse podocytes, and increases ROS levels in cells and mitochondria. Moreover, the expression of nephrin was downregulated and the cell apoptotic rate was increased. Resveratrol treatment can improve abnormalities caused by high-glucose stimulation. In addition, it can also reduce the release of mitochondrial cytochrome C and DIABLO proteins to the cytoplasm and increase respiratory chain complex I and III activity and mitochondrial membrane potential. CONCLUSIONS Resveratrol can reduce the oxidative damage and apoptosis of podocytes induced by high-glucose stimulation via SIRT1/PGC-1α-mediated mitochondrial protection.

Dexamethasone mediated downregulation of PGC-1α and visfatin regulates testosterone synthesis and antioxidant system in mouse testis.

Dexamethasone, a synthetic glucocorticoid has been used as an immunosuppressive and anti-inflammatory and affects reproduction. It has been suggested that testicular steroidogenesis involves PGC-1α and visfatin as key regulators. Previous studies have shown that dexamethasone down-regulates PGC-1α and visfatin expression in muscle and mammary epithelial cells respectively. However, the effect of dexamethasone on testicular visfatin and PGC-1α expressions has not been investigated. The aims of the present study were to investigate the effect of dexamethasone, on the expression of PGC-1α, visfatin and antioxidant enzymes activities in mouse testis. The results of the present study showed that dexamethasone treatment significantly decreased the expression of visfatin and PGC-1α in mice testis, along with significant decreased in testicular antioxidant enzymes activates. Further, dexamethasone treatment also significantly increased the testicular lipid peroxidation and decreased testosterone synthesis. The dexamethasone induced changes in PGC-1α and visfatin in the testis were significantly correlated with changes in serum testosterone concentrations and antioxidant enzymes activities. Thus, dexamethasone induced testicular toxicity may involve the PGC-1α and visfatin as important molecules to exhibit its effects.

Hypoxia modulates the antioxidant effect of hydroxytyrosol in MCF-7 breast cancer cells.

Although cancer is multifactorial, a strong correlation between this pathology and increased oxidative stress has long been stablished. Hypoxia, inherent to solid tumors, increases reactive oxygen species and should be taken into account when analyzing the response of tumor cells to antioxidants. The Mediterranean diet has been related to a lower incidence of cancer, and particularly of breast cancer. Given that hydroxytyrosol (HT) is largely responsible for the antioxidant properties of olive oil, we have performed a comprehensive and comparative study of its effect on the oxidative stress response of the human breast cancer cell line MCF-7 in hypoxia and normoxia. Our results demonstrate that the antioxidant action of HT is particularly effective in a hypoxic environment. Moreover, we have observed that this polyphenol modulates the transcription and translation of members of the PGC-1α/ERRα and PGC-1α/Nrf2 pathways. However, while the transcriptional effects of HT are similar in normoxic and hypoxic conditions, its translational action is less prominent and partially attenuated in hypoxia, and therefore cannot completely explain the antioxidant effect of HT. Consequently, our results underscore that the hypoxic environment of tumor cells should be considered when analyzing the effect of bioactive compounds. Besides, this study also points to the importance of assessing the regulatory role of HT at both mRNA and protein level to get a complete picture of its effects.

Peroxisome Proliferator-Activated Receptor Gamma Coactivator-1 Alpha as a Novel Target for Bipolar Disorder and Other Neuropsychiatric Disorders.

Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1 alpha) is a protein that regulates metabolism and inflammation by activating nuclear receptors, especially the family of peroxisome proliferator-activated receptors (PPARs). PGC-1 alpha and PPARs also regulate mitochondrial biogenesis, cellular energy production, thermogenesis, and lipid metabolism. Brain energy metabolism may also be regulated in part by the interaction between PGC-1 alpha and PPARs. Because neurodegenerative diseases (Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis) and bipolar disorder have been associated with dysregulated mitochondrial and brain energy metabolism, PGC-1 alpha may represent a potential drug target for these conditions. The purpose of this article is to review the physiology of PGC-1 alpha, PPARs, and the role of PPAR agonists to target PGC-1 alpha to treat neurodegenerative diseases and bipolar disorder. We also review clinical trials of repurposed antidiabetic thiazolidines and anti-triglyceride fibrates (PPAR agonists) for neurodegenerative diseases and bipolar disorder. PGC-1 alpha and PPARs are innovative potential targets for bipolar disorder and warrant future clinical trials.

Schisandrin C enhances odontoblastic differentiation through autophagy and mitochondrial biogenesis in human dental pulp cells.

OBJECTIVE: To investigate the role of Schisandrin C in odontoblastic differentiation, and its relations between autophagy and mitochondrial biogenesis in human dental pulp cells (HPDCs). DESIGN: Fresh third molars were used, and cultured for HDPCs. Western blotting technique, Alizarin red S staining, alkaline phosphatase (ALP) activity, and confocal microscopy were used to detect autophagy, mitochondrial biogenesis, and odontoblastic differentiation. To understand the mechanism of Schisandrin C, the HDPCs were treated with lipopolysaccharide (LPS), autophagy and heme oxygenase-1 (HO-1) inhibitors: 3-Methyladenine (3-MA) and Zinc protoporphyrin IX (ZnPP), respectively. RESULTS: LPS decreased the expression of autophagy molecules [autophagy protein 5 (ATG-5), beclin-1, and microtubule-associated protein 1A/1B light chain 3 (LC3-I/II)] and mitochondrial biogenesis molecules [heme oxygenase-1 (HO-1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)], and disrupted odontoblastic differentiation. The down-regulation of autophagy and mitochondrial biogenesis with 3-MA and ZnPP inhibited odontoblastic differentiation. However, Schisandrin C restored the expression of all the above molecules, even with LPS and inhibitor treatment. This result demonstrates that autophagy and mitochondrial biogenesis plays an essential role in odontoblastic differentiation, and Schisandrin C activates these systems to promote odontoblastic differentiation of HDPCs. CONCLUSION: Schisandrin C has potential characters to regulate odontoblastic differentiation, and may be recommended for use as a compound for pulp homeostasis.

Effect of baicalin on GLUT4 expression and glucose uptake in myotubes of rats.

AIMS: Although baicalin could attenuate obesity-induced insulin resistance, the detailed mechanism of baicalin on glucose uptake has not been sufficiently explored as yet. The aim of this study was to survey if baicalin might facilitate glucose uptake and to explore its signal mechanisms in L6 myotubes. MATERIALS AND METHODS: L6 myotubes were treated with 100, 200, 400 µM baicalin for 6 h, 12 h and 24 h in this study. Then 2-NBDG and insulin signal protein levels in myotubes of L6 cells were examined. KEY FINDINGS: We discovered that administration of baicalin enhanced GLUT4, PGC-1α, pP38MAPK, pAKT and pAS160 contents, as well as GLUT4 mRNA and PGC-1α mRNA levels in L6 myotubes. The beneficial metabolic changes elicited by baicalin were abrogated in myotubes of L6 by P38MAPK or AKT inhibitors. SIGNIFICANCE: These results suggest that baicalin promoted glucose uptake in myotubes by differential regulation on P38MAPK and AKT activity. In conclusion, these data provide insight that baicalin is a powerful and promising agent for the treament of hyperglycemia via AKT/AS160/GLUT4 and P38MAPK/PGC1α/GLUT4 pathway.

The PGC-1α Activator ZLN005 Ameliorates Ischemia-Induced Neuronal Injury In Vitro and In Vivo.

Oxidative stress is a great challenge to neurons following cerebral ischemia. PGC-1α has been shown to act as a potent modulator of oxidative metabolism. In this study, the effects of ZLN005, a small molecule that activate PGC-1α, against oxygen-glucose deprivation (OGD)- or ischemia-induced neuronal injury in vitro and in vivo were investigated. Transient middle cerebral artery occlusion (tMCAO) was performed in rats and ZLN005 was administered intravenously at 2 h, 4 h, or 6 h after ischemia onset. Infarct volume and neurological deficit score were detected to evaluate the neuroprotective effects of ZLN005. Well-differentiated PC12 cells, which were subjected to OGD for 2 h followed by reoxygenation for 22 h, were used as an in vitro ischemic model. Changes in expression of PGC-1α, its related genes, and antioxidant genes were determined by real-time quantitative PCR. The results showed that ZLN005 reduced cerebral infarct volume and improved the neurological deficit in rat with tMCAO, and significantly protected OGD-induced neuronal injury in PC12 cells. Furthermore, ZLN005 enhanced expression of PGC-1α in PC12 cells and in the ipsilateral hemisphere of rats with tMCAO. Additionally, ZLN005 increased antioxidant genes, including SOD1 and HO-1, and significantly prevented the ischemia-induced decrease in SOD activity. Taking together, the PGC-1α activator ZLN005 exhibits neuroprotective effects under ischemic conditions and molecular mechanisms possibly involve activation of PGC-1α signaling pathway and cellular antioxidant systems.