Markers Of Mitochondrial Biogenesis Research Articles

The Mitochondria-Targeting Agent MitoQ Improves Muscle Atrophy, Weakness and Oxidative Metabolism in C26 Tumor-Bearing Mice.

Cancer cachexia is a debilitating syndrome characterized by skeletal muscle wasting, weakness and fatigue. Several pathogenetic mechanisms can contribute to these muscle derangements. Mitochondrial alterations, altered metabolism and increased oxidative stress are known to promote muscle weakness and muscle catabolism. To the extent of improving cachexia, several drugs have been tested to stimulate mitochondrial function and normalize the redox balance. The aim of this study was to test the potential beneficial anti-cachectic effects of Mitoquinone Q (MitoQ), one of the most widely-used mitochondria-targeting antioxidant. Here we show that MitoQ administration (25 mg/kg in drinking water, daily) in vivo was able to improve body weight loss in Colon-26 (C26) bearers, without affecting tumor size. Consistently, the C26 hosts displayed ameliorated skeletal muscle and strength upon treatment with MitoQ. In line with improved skeletal muscle mass, the treatment with MitoQ was able to partially correct the expression of the E3 ubiquitin ligases Atrogin-1 and Murf1. Contrarily, the anabolic signaling was not improved by the treatment, as showed by unchanged AKT, mTOR and 4EBP1 phosphorylation. Assessment of gene expression showed altered levels of markers of mitochondrial biogenesis and homeostasis in the tumor hosts, although only Mitofusin-2 levels were significantly affected by the treatment. Interestingly, the levels of Pdk4 and CytB, genes involved in the regulation of mitochondrial function and metabolism, were also partially increased by MitoQ, in line with the modulation of hexokinase (HK), pyruvate dehydrogenase (PDH) and succinate dehydrogenase (SDH) enzymatic activities. The improvement of the oxidative metabolism was associated with reduced myosteatosis (i.e., intramuscular fat infiltration) in the C26 bearers receiving MitoQ, despite unchanged muscle LDL receptor expression, therefore suggesting that MitoQ could boost β-oxidation in the muscle tissue and promote a glycolytic-to-oxidative shift in muscle metabolism and fiber composition. Overall, our data identify MitoQ as an effective treatment to improve skeletal muscle mass and function in tumor hosts and further support studies aimed at testing the anti-cachectic properties of mitochondria-targeting antioxidants also in combination with routinely administered chemotherapy agents.

Impact of high-intensity interval training with or without l-citrulline on physical performance, skeletal muscle, and adipose tissue in obese older adults.

BackgroundAging is associated with a progressive decline in skeletal muscle mass and strength as well as an increase in adiposity. These changes may have devastating impact on the quality of life of older adults. Mitochondrial dysfunctions have been implicated in aging‐related and obesity‐related deterioration of muscle function. Impairments in mitochondrial quality control processes (biogenesis, fusion, fission, and mitophagy) may underlie this accumulation of mitochondrial dysfunction. High‐intensity interval training (HIIT) was shown to improve muscle and mitochondrial function in healthy young and old adults and to improve body composition in obese older adults. Recent studies also positioned citrulline (CIT) supplementation as a promising intervention to counter obesity‐related and aging‐related muscle dysfunction. In the present study, our objectives were to assess whether HIIT, alone or with CIT, improves muscle function, functional capacities, adipose tissue gene expression, and mitochondrial quality control processes in obese older adults.MethodsEighty‐one‐old and obese participants underwent a 12 week HIIT with or without CIT on an elliptical trainer [HIIT‐CIT: 20 men/25 women, 67.2 ± 5.0 years; HIIT‐placebo (PLA): 18 men/18 women, 68.1 ± 4.1 years]. Handgrip and quadriceps strength, lower limb muscle power, body composition, waist circumference, and functional capacities were assessed pre and post intervention. Vastus lateralis muscle biopsies were performed in a subset of participants to quantify markers of mitochondrial content (TOM20 and OXPHOS subunits), biogenesis (TFAM), fusion (MFN1&2, OPA1), fission (DRP1), and mitophagy (Parkin). Subcutaneous abdominal adipose tissue biopsies were also performed to assess the expression of genes involved in lipid metabolism.ResultsHIIT‐PLA and HIIT‐CIT displayed improvements in functional capacities (P < 0.05), total (mean ± SD: HIIT‐PLA: +1.27 ± 3.19%, HIIT‐CIT: +1.05 ± 2.91%, P < 0.05) and leg lean mass (HIIT‐PLA: +1.62 ± 3.85%, HIIT‐CIT: +1.28 ± 4.82%, P < 0.05), waist circumference (HIIT‐PLA: −2.2 ± 2.9 cm, HIIT‐CIT: −2.6 ± 2.5 cm, P < 0.05), and muscle power (HIIT‐PLA: +15.81 ± 18.02%, HIIT‐CIT: +14.62 ± 20.02%, P < 0.05). Only HIIT‐CIT decreased fat mass (−1.04 ± 2.42%, P < 0.05) and increased handgrip and quadriceps strength (+4.28 ± 9.36% and +10.32 ± 14.38%, respectively, P < 0.05). Both groups increased markers of muscle mitochondrial content, mitochondrial fusion, and mitophagy (P < 0.05). Only HIIT‐CIT decreased the expression of the lipid droplet‐associated protein CIDEA (P < 0.001).ConclusionsHigh‐intensity interval training is effective in improving functional capacities, lean mass, muscle power, and waist circumference in obese older adults. HIIT also increases markers of mitochondrial biogenesis, mitochondrial fusion, and mitophagy. Importantly, adding CIT to HIIT results in a greater increase in muscle strength and a significant decrease in fat mass. The present study therefore positions HIIT combined with CIT as an effective intervention to improve the health status of obese older adults.

Vanillic acid induces mitochondrial biogenesis in SH-SY5Y cells.

Mitochondrial dysfunction has been recognized as an important mechanism of neurodegeneration. Accumulating evidence now suggests that defects in mitochondrial biogenesis can cause mitochondrial dysfunction in neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Therefore, identifying small molecules that can stimulate mitochondrial biogenesis may represent a therapeutic strategy for neuroprotection. The aim of this study was to investigate the effects of a natural compound vanillic acid (VA) on mitochondrial biogenesis and the expression of PD-related genes in SH-SY5Y cells. After determining the IC50 and non-toxic concentrations of VA, SH-SY5Y cells were exposed to a non-toxic dose of VA (300 µM) for 18h. VA treatment resulted in significant increases in the mRNA expressions of mitochondrial biogenesis markers, PGC-1α and TFAM. Moreover, treatment of SH-SY5Y cells with 300 µM VA for 24h significantly elevated the mitochondrial DNA (mtDNA) copy number and mitochondrial mass. Furthermore, the effects of VA on the expression of PD-related genes were analyzed using a real-time PCR array. The PCR array analysis revealed that VA can induce the expression of some genes involved in neuronal differentiation and also affect the expression of two PARK genes, PARK2 and LRRK2, whose mutations cause familial PD. Together, these findings indicate that VA could serve as a potential neuroprotective agent by virtue of its ability to stimulate mitochondrial biogenesis in neuronal cells and to alter the expression of some genes related to the pathogenesis of PD and neuronal differentiation.

The effect of eight weeks of aerobic training with Propolis on some mitochondrial biogenesis markers in cardiac tissue of ovariectomized diabetic rats

The effect of eight weeks of aerobic training with Propolis on some mitochondrial biogenesis markers in cardiac tissue of ovariectomized diabetic rats

Early Cellular, Molecular, Morphological and Behavioral Changes in the Humanized Amyloid-Beta-Knock-In Mouse Model of Late-Onset Alzheimer's Disease.

The purpose of our study is to investigate early cellular, molecular, morphological and behavioral changes in humanized amyloid-beta-knock-in (hAbKI) mice. Using seven-month-old homozygous hAbKI mice, we studied behavioral phenotype parameters, including spatial learning and memory (Morris Water Maze), locomotor activity (open field), working memory (Y-maze) and motor coordination (rotarod); mRNA abundance, protein levels, soluble amyloid-beta 40 and 42 levels and regional immunoreactivities of key markers of mitochondrial dynamics, mitochondrial biogenesis, synaptic health, mitophagy and autophagy; mitochondrial function and using transmission electron microscopy & Golgi–Cox staining, we assessed mitochondrial morphology and dendritic spines. Our extensive behavioral analysis revealed that seven-month-old hAbKI mice showed impairments in motor coordination, reduced locomotor and exploration activities, impairments in working memory and spatial learning and memory. Our mRNA and protein analyses revealed the increased expression of mitochondrial-fission genes and reduced expression of mitochondrial-fusion, mitochondrial-biogenesis, synaptic, autophagy and mitophagy genes in seven-month-old hAbKI mice. An immunofluorescence analysis revealed altered immunoreactivities and agreed with the immunoblot results. Transmission-electron-microscopy data revealed increased mitochondrial fragmentation and reduced mitochondrial length in both hippocampal and cortical tissues of seven-month-old hAbKI mice and mitochondrial function defective. A Golgi–Cox-staining analysis revealed reduced dendritic spines in both cerebral cortices and hippocampi of hAbKI mice. Soluble amyloid-beta (1–40 and 1–42) were detected in three-month-old hAbKI mice and progressively increased in seven-month-old mice. These observations suggest that the human amyloid-beta peptide is sufficient to cause behavioral, mitochondrial, synaptic and ultrastructural changes in seven-month-old hAbKI mice. Our study findings also suggest that hAbKI mice might serve as a model for preclinical studies of preventive therapies.

Sex- and strain-specific effects of mitochondrial uncoupling on age-related metabolic diseases in high-fat diet-fed mice.

Mild uncoupling of oxidative phosphorylation is an intrinsic property of all mitochondria and may have evolved to protect cells against the production of damaging reactive oxygen species. Therefore, compounds that enhance mitochondrial uncoupling are potentially attractive anti‐aging therapies; however, chronic ingestion is associated with a number of unwanted side effects. We have previously developed a controlled‐release mitochondrial protonophore (CRMP) that is functionally liver‐directed and promotes oxidation of hepatic triglycerides by causing a subtle sustained increase in hepatic mitochondrial inefficiency. Here, we sought to leverage the higher therapeutic index of CRMP to test whether mild mitochondrial uncoupling in a liver‐directed fashion could reduce oxidative damage and improve age‐related metabolic disease and lifespan in diet‐induced obese mice. Oral administration of CRMP (20 mg/[kg‐day] × 4 weeks) reduced hepatic lipid content, protein kinase C epsilon activation, and hepatic insulin resistance in aged (74‐week‐old) high‐fat diet (HFD)‐fed C57BL/6J male mice, independently of changes in body weight, whole‐body energy expenditure, food intake, or markers of hepatic mitochondrial biogenesis. CRMP treatment was also associated with a significant reduction in hepatic lipid peroxidation, protein carbonylation, and inflammation. Importantly, long‐term (49 weeks) hepatic mitochondrial uncoupling initiated late in life (94–104 weeks), in conjugation with HFD feeding, protected mice against neoplastic disorders, including hepatocellular carcinoma (HCC), in a strain and sex‐specific manner. Taken together, these studies illustrate the complex variation of aging and provide important proof‐of‐concept data to support further studies investigating the use of liver‐directed mitochondrial uncouplers to promote healthy aging in humans.

Effect of Porcine Whole Blood Protein Hydrolysate on Slow-Twitch Muscle Fiber Expression and Mitochondrial Biogenesis via the AMPK/SIRT1 Pathway

Skeletal muscle is a heterogeneous tissue composed of a variety of functionally different fiber types. Slow-twitch type I muscle fibers are rich with mitochondria, and mitochondrial biogenesis promotes a shift towards more slow fibers. Leucine, a branched-chain amino acid (BCAA), regulates slow-twitch muscle fiber expression and mitochondrial function. The BCAA content is increased in porcine whole-blood protein hydrolysates (PWBPH) but the effect of PWBPH on muscle fiber type conversion is unknown. Supplementation with PWBPH (250 and 500 mg/kg for 5 weeks) increased time to exhaustion in the forced swimming test and the mass of the quadriceps femoris muscle but decreased the levels of blood markers of exercise-induced fatigue. PWBPH also promoted fast-twitch to slow-twitch muscle fiber conversion, elevated the levels of mitochondrial biogenesis markers (SIRT1, p-AMPK, PGC-1α, NRF1 and TFAM) and increased succinate dehydrogenase and malate dehydrogenase activities in ICR mice. Similarly, PWBPH induced markers of slow-twitch muscle fibers and mitochondrial biogenesis in C2C12 myotubes. Moreover, AMPK and SIRT1 inhibition blocked the PWBPH-induced muscle fiber type conversion in C2C12 myotubes. These results indicate that PWBPH enhances exercise performance by promoting slow-twitch muscle fiber expression and mitochondrial function via the AMPK/SIRT1 signaling pathway.

Bone morphogenic protein 9 is a novel thermogenic hepatokine secreted in response to cold exposure

ObjectiveMaintaining a constant core body temperature is essential to homeothermic vertebrate survival. Adaptive thermogenesis in brown adipose tissue and skeletal muscle is the primary mechanism of adjustment to an external stimulus such as cold exposure. Recently, several reports have revealed that the liver can play a role as a metabolic hub during adaptive thermogenesis. In this study, we suggest that the liver plays a novel role in secreting thermogenic factors in adaptive thermogenesis. Bone morphogenetic protein 9 (BMP9) is a hepatokine that regulates many biological processes, including osteogenesis, chondrogenesis, hematopoiesis, and angiogenesis. Previously, BMP9 was suggested to affect preadipocyte proliferation and differentiation. However, the conditions and mechanisms underlying hepatic expression and secretion and adipose tissue browning of BMP9 remain largely unknown. In this study, we investigated the physiological conditions for secretion and the regulatory mechanism of hepatic Bmp9 expression and the molecular mechanism by which BMP9 induces thermogenic gene program activation in adipose tissue. Here, we also present the pharmacological effects of BMP9 on a high-fat-induced obese mouse model. MethodsTo investigate the adaptive thermogenic role of BMP9 in vivo, we challenged mice with cold temperature exposure for 3 weeks and then examined the BMP9 plasma concentration and hepatic expression level. The cellular mechanism of hepatic Bmp9 expression under cold exposure was explored through promoter analysis. To identify the role of BMP9 in the differentiation of brown and beige adipocytes, we treated pluripotent stem cells and inguinal white adipose tissue (iWAT)-derived stromal-vascular (SV) cells with BMP9, and brown adipogenesis was monitored by examining thermogenic gene expression and signaling pathways. Furthermore, to evaluate the effect of BMP9 on diet-induced obesity, changes in body composition and glucose tolerance were analyzed in mice administered recombinant BMP9 (rBMP9) for 8 weeks. ResultsHepatic Bmp9 expression and plasma levels in mice were significantly increased after 3 weeks of cold exposure. Bmp9 mRNA expression in the liver was regulated by transcriptional activation induced by cAMP response-element binding protein (CREB) and CREB-binding protein (CBP) on the Bmp9 promoter. Treatment with BMP9 promoted the differentiation of multipotent stem cells and iWAT-derived SV cells into beige adipocytes, as indicated by the increased expression of brown adipocyte and mitochondrial biogenesis markers. Notably, activation of the mothers against decapentaplegic homolog 1 (Smad1) and p44/p42 mitogen-activated protein kinase (MAPK) pathways was required for the induction of uncoupling protein 1 (UCP1) and peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC1α) expression in BMP9-induced differentiation of SVs into beige adipocytes. The administration of rBMP9 in vivo also induced browning markers in white adipose tissue. In high-fat diet-induced obese mice, rBMP9 administration conferred protection against obesity and enhanced glucose tolerance. ConclusionsBMP9 is a hepatokine regulated by cold-activated CREB and CBP and enhances glucose and fat metabolism by promoting the activation of the thermogenic gene program in adipocytes. These data implicate BMP9 as a potential pharmacological tool for protecting against obesity and type 2 diabetes.

FUNDC1 activates the mitochondrial unfolded protein response to preserve mitochondrial quality control in cardiac ischemia/reperfusion injury

The mitochondrial unfolded protein response (UPRmt) is an adaptive transcriptional response involving the activation of proteases, chaperones, and antioxidant enzymes and serves to degrade abnormal or unfolded proteins and restore mitochondrial function. Although the cardioprotective action of the UPRmt has been verified in myocardial ischemia/reperfusion (I/R) injuries, the upstream signals involved remain unclear. Here, we explored the regulatory mechanisms underlying UPRmt in the reperfused mouse heart. UPRmt was slightly activated by I/R injury. UPRmt activation (using oligomycin) and inhibition (with the protease inhibitor AEBSF) respectively alleviated and augmented the reperfusion-mediated myocardial damage. Gene expression analysis demonstrated that oxidative stress was partly inhibited by UPRmt through upregulation of mitochondria-localized, not cytoplasmic, antioxidant enzymes. Contributing to cardiomyocyte survival under I/R, the transcription of pro-apoptotic proteins Bcl2 and c-IAP was also stimulated by UPRmt. Moreover, UPRmt upregulated mitochondrial fusion-related, but not fission-related, genes and stimulated the expression of mitochondrial biogenesis markers in reperfused hearts. Finally, we found that FUN14 domain containing 1 (FUNDC1)-mediated mitophagy induces the mitochondrial DNA decrease, triggering UPRmt. These results demonstrate that FUNDC1 functions upstream of the UPRmt to maintain mitochondrial quality control during myocardial I/R injury.

Cinnamic acid derivative reduces tumor growth by decreasing Hif-1α expression and suppressing the Warburg effect

Background. Tumor growth is characterized by the presence of specific features that can be the basis for rational treatment. One of these features is the Warburg paradox, which manifests itself in the prevalence of glycolytic oxidation reactions over aerobic metabolism at adequate intracellular oxygen concentrations. Purpose. Under experimental conditions, to evaluate the possibility of correcting metabolic glycolytic abnormalities of tumor cells through course therapy with 4-hydroxy-3,5-di-tretbutyl cinnamic acid. Materials and methods. The study was performed on male Wistar rats, in which tumor cells of the C6-BU-1 line were implanted in the brain. The test compound 4-hydroxy3,5-di-tret butyl cinnamic acid and reference resveratrol were administered per os at doses of 100 mg/kg and 20 mg/kg, respectively, for 14 days from the moment of tumor inoculation. After the specified time, the rats were decapitated, the tumor tissue was extracted. In the course of the work, the volume of the tumor, the activity of ana/aerobic reactions of cellular metabolism, changes in mitochondrial biogenesis and the concentration of Hif-1a were determined. Results. The study showed that the course administration of resveratrol and 4-hydroxy3,5-di-tret butyl cinnamic acid contributed to a decrease in tumor volume compared to untreated animals by 22.9 % (p &lt; 0.05) and 34.3 % (p &lt; 0.05), respectively. Also, against the background of the use of the studied compound, there was a decrease in the content of Hif-1a by 27.4 % (p &lt; 0.05), respectively, an increase in the activity of the enzymatic markers of mitochondrial biogenesis – succinate dehydrogenase and cytochrome-c oxidase by 166.7 % (p &lt; 0.05) and 125.0 % (p &lt; 0.05). The intensity of anaerobic metabolic reactions in rats treated by the test compound and resveratrol was significantly lower than in untreated rats, while the activity of aerobic processes considerably increased. Conclusion. The study showed that the administration of 4-hydroxy-3,5-di-tret butyl cinnamic acid reduces the intensity of anaerobic metabolism in tumor cells by reducing the expression of Hif-1a, which in turn suppresses tumor growth.

Nanocurcumin potential to increase mitochondrial biogenesis in skeletal muscle via AMPK-PGC-1alpha

Curcumin, which comes from the rhizome Curcuma longa L, is known as the polyphenol with a high level content of natural antioxidants and has benefits on pharmacological activities and human health. The purpose of current study was to investigate the effect of nanocurcumin itself and the combination with exercise on 5' adenosine monophosphate-activated protein kinase (AMPK), PGC-1α, and mitochondrial protein expression of cytochrome c oxidase subunit IV (COX-IV), in rat gastrocnemius muscle. Animals separated to be non-endurance exercise and endurance exercise group. Curcumin and nanocurcumin with doses 100 mg per kg-body weight per day were given peroral in both groups for 28 days in order to determine the effect of nanocurcumin on mitochondrial markers including AMPK-PGC-1α and COX-IV. Western blotting (WB) method was applied to investigate the protein expression on skeletal muscle. The result showed that nanocurcumin increased mitochondrial marker protein COX-IV on non exercise and exercise groups. Furthermore, our result demonstrated that nanocurcumin treatment combined with exercise increased the phosphorylation of AMPK and PGC-1α. Addition, nanocurcumin treatment alone, without exercise, also increased PGC-1α protein expression. This current result suggests that nanocurcumin could increase mitochondrial biogenesis markers. When it is used together with exercise, it potentially has the additive effect of exercise to increase mitochondrial markers through AMPK-PGC-1α signaling pathway. In conclusion, nanocurcumin treatment combined with exercise potentially increases mitochondrial biogenesis.

Ultrastructural changes in cristae of lymphoblasts in acute lymphoblastic leukemia parallel alterations in biogenesis markers

We explored the link between mitochondrial biogenesis and mitochondrial morphology using transmission electron microscopy (TEM) in lymphoblasts of pediatric acute lymphoblastic leukemia (ALL) patients and compared these characteristics between tumors and control samples. Gene expression of mitochondrial biogenesis markers was analysed in 23 ALL patients and 18 controls and TEM for morphology analysis was done in 15 ALL patients and 9 healthy controls. The area occupied by mitochondria per cell and the cristae cross-sectional area was observed to be significantly higher in patients than in controls (p-value = 0.0468 and p-value< 0.0001, respectively). The mtDNA copy numbers, TFAM, POLG, and c-myc gene expression were significantly higher in ALL patients than controls (all p-values< 0.01). Gene Expression of PGC-1α was higher in tumor samples. The analysis of the correlation between PGC-1α expression and morphology parameters i.e., both M/C ratio and cristae cross-sectional area revealed a positive trend (r = 0.3, p = 0.1). The increased area occupied by mitochondria and increased cristae area support the occurrence of cristae remodelling in ALL. These changes might reflect alterations in cristae dynamics to support the metabolic state of the cells by forming a more condensed network. Ultrastructural imaging can be useful for affirming changes occurring at a subcellular organellar level.

Glucosamine Supplementation Improves Physical Performance in Trained Mice.

d-Glucosamine (GlcN) is one of the most widely consumed dietary supplements and complementary medicines in the world and has been traditionally used to attenuate osteoarthritis in humans. GlcN extends life span in different animal models. In humans, its supplementation has been strongly associated with decreased total mortality and improved vascular endothelial function. GlcN acts as a suppressor of inflammation, and by inhibiting glycolysis, it can activate the metabolism of stored fat and mitochondrial respiration. The conventional human GlcN dose is 1500 mg·d-1, but extensive evidence indicates that much higher doses are well tolerated. GlcN is one of the supplements that has experienced a greater use in the last years in elite athletes mainly because of its potential chondroprotective effects that may promote cartilage health. However, the possibility of it being an ergogenic aid has not been explored. We aimed to study the potential beneficial effects of GlcN on mitochondrial content, physical performance, and oxidative stress in mice that were aerobically trained and supplemented with three different doses of glucosamine (250, 500, and 1000 mg·kg-1) for 6 wk. We measured exercise performance (grip strength, motor coordination, and running capacity) before and after the training period. Proteins involved in mitochondrial biogenesis (AMPK, PGC-1, NRF-1, SIRT-1, cytochrome c, citrate synthase), markers of oxidative stress (GSSG/GSH) or damage (malondialdehyde, carbonylated proteins), antioxidant enzymes (NRF-2, SOD1, SOD2, catalase, and PRDX6), and MAPKs (p38 and ERK1/2 were also determined in skeletal muscle. Our results show that GlcN supplementation in aerobically trained mice, at doses equivalent to those conventionally used in humans, increases the protein levels of mitochondrial biogenesis markers, improves motor coordination, and may have a synergistic effect with exercise training on running distance.

Mitochondria-Targeted Hydrogen Sulfide Delivery Molecules Protect Against UVA-Induced Photoaging in Human Dermal Fibroblasts, and in Mouse Skin In Vivo.

Aims: Oxidative stress and mitochondrial dysfunction play a role in the process of skin photoaging via activation of matrix metalloproteases (MMPs) and the subsequent degradation of collagen. The activation of nuclear factor E2-related factor 2 (Nrf2), a transcription factor controlling antioxidant and cytoprotective defense systems, might offer a pharmacological approach to prevent skin photoaging. We therefore investigated a pharmacological approach to prevent skin photoaging, and also investigated a protective effect of the novel mitochondria-targeted hydrogen sulfide (H2S) delivery molecules AP39 and AP123, and nontargeted control molecules, on ultraviolet A light (UVA)-induced photoaging in normal human dermal fibroblasts (NHDFs) in vitro and the skin of BALB/c mice in vivo. Results: In NHDFs, AP39 and AP123 (50-200 nM) but not nontargeted controls suppressed UVA (8 J/cm2)-mediated cytotoxicity and induction of MMP-1 activity, preserved cellular bioenergetics, and increased the expression of collagen and nuclear levels of Nrf2. In in vivo experiments, topical application of AP39 or AP123 (0.3-1 μM/cm2; but not nontargeted control molecules) to mouse skin before UVA (60 J/cm2) irradiation prevented skin thickening, MMP induction, collagen loss of oxidative stress markers 8-hydroxy-2'-deoxyguanosine (8-OHdG), increased Nrf2-dependent signaling, as well as increased manganese superoxide dismutase levels and levels of the mitochondrial biogenesis marker peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α). Innovation and Conclusion: Targeting H2S delivery to mitochondria may represent a novel approach for the prevention and treatment of skin photoaging, as well as being useful tools for determining the role of mitochondrial H2S in skin disorders and aging. Antioxid. Redox Signal. 36, 1268-1288.

Skeletal Muscle Mitochondrial Physiology in Children With Cerebral Palsy: Considerations for Healthy Aging.

Skeletal muscle contractile proteins require a constant supply of energy to produce force needed for movement. Energy (ATP) is primarily produced by mitochondrial organelles, located within and around muscle fibers, by oxidative phosphorylation that couples electron flux through the electron transport chain to create a proton gradient across the inner mitochondrial membrane that is in turn used by the ATP synthase. Mitochondrial networks increase in size by biogenesis to increase mitochondrial abundance and activity in response to endurance exercise, while their function and content reduce with constant inactivity, such as during muscle atrophy. During healthy aging, there is an overall decline in mitochondrial activity and abundance, increase in mitochondrial DNA mutations, potential increase in oxidative stress, and reduction in overall muscular capacity. Many of these alterations can be attenuated by consistent endurance exercise. Children with cerebral palsy (CP) have significantly increased energetics of movement, reduced endurance capacity, and increased perceived effort. Recent work in leg muscles in ambulatory children with CP show a marked reduction in mitochondrial function. Arm muscles show that mitochondrial protein content and mitochondria DNA copy number are lower, suggesting a reduction in mitochondrial abundance, along with a reduction in markers for mitochondrial biogenesis. Gene expression networks are reduced for glycolytic and mitochondrial pathways and share similarities with gene networks with aging and chronic inactivity. Given the importance of mitochondria for energy production and changes with aging, future work needs to assess changes in mitochondria across the lifespan in people with CP and the effect of exercise on promoting metabolic health.

Hyperglycemia alters mitochondrial respiration efficiency and mitophagy in human podocytes

Podocytes constitute the outer layer of the renal glomerular filtration barrier. Their energy requirements strongly depend on efficient oxidative respiration, which is tightly connected with mitochondrial dynamics. We hypothesized that hyperglycemia modulates energy metabolism in glomeruli and podocytes and contributes to the development of diabetic kidney disease. We found that oxygen consumption rates were severely reduced in glomeruli from diabetic rats and in human podocytes that were cultured in high glucose concentration (30 mM; HG). In these models, all of the mitochondrial respiratory parameters, including basal and maximal respiration, ATP production, and spare respiratory capacity, were significantly decreased. Podocytes that were treated with HG showed a fragmented mitochondrial network, together with a decrease in expression of the mitochondrial fusion markers MFN1, MFN2, and OPA1, and an increase in the activity of the fission marker DRP1. We showed that markers of mitochondrial biogenesis, such as PGC-1α and TFAM, decreased in HG-treated podocytes. Moreover, PINK1/parkin-dependent mitophagy was inhibited in these cells. These results provide evidence that hyperglycemia impairs mitochondrial dynamics and turnover, which may underlie the remarkable deterioration of mitochondrial respiration parameters in glomeruli and podocytes.

Glucocorticoid maturation of mitochondrial respiratory capacity in skeletal muscle before birth.

In adults, glucocorticoids act to match the supply and demand for energy during physiological challenges, partly through actions on tissue mitochondrial oxidative phosphorylation (OXPHOS) capacity. However, little is known about the role of the natural prepartum rise in fetal glucocorticoid concentrations in preparing tissues for the increased postnatal energy demands. This study examined the effect of manipulating cortisol concentrations in fetal sheep during late gestation on mitochondrial OXPHOS capacity of two skeletal muscles with different postnatal locomotive functions. Mitochondrial content, biogenesis markers, respiratory rates and expression of proteins and genes involved in the electron transfer system (ETS) and OXPHOS efficiency were measured in the biceps femoris (BF) and superficial digital flexor (SDF) of fetuses either infused with cortisol before the prepartum rise or adrenalectomised to prevent this increment. Cortisol infusion increased mitochondrial content, biogenesis markers, substrate-specific respiration rates and abundance of ETS complex I and adenine nucleotide translocator (ANT1) in a muscle-specific manner that was more pronounced in the SDF than BF. Adrenalectomy reduced mitochondrial content and expression of PGC1α and ANT1 in both muscles, and ETS complex IV abundance in the SDF near term. Uncoupling protein gene expression was unaffected by cortisol manipulations in both muscles. Gene expression of the myosin heavy chain isoform, MHCIIx, was increased by cortisol infusion and reduced by adrenalectomy in the BF alone. These findings show that cortisol has a muscle-specific role in prepartum maturation of mitochondrial OXPHOS capacity with important implications for the health of neonates born pre-term or after intrauterine glucocorticoid overexposure.

Mitofusion is required for MOTS\u2010c induced GLUT4 translocation

MOTS‐c (mitochondrial ORF of the twelve S-c) is a 16-amino-acid mitochondrial peptide that has been shown to counter insulin resistance and alleviate obesity in vivo. However, the mechanisms involved in the pharmacological action of MOTS-c remain elusive. Based on the ability of MOTS-c to improve insulin resistance and promote cold adaptation, we hypothesized that MOTS-c might play a role in boosting the number of mitochondria in a cell. We found that treatment of mammalian cells with MOTS‐c increased protein levels of TFAM, COX4, and NRF1, which are markers for mitochondrial biogenesis. However, flow cytometry analysis using MitoTracker Green revealed a sharp reduction in the mitochondrial count after MOTS‐c treatment. We then anticipated possible synchronized activation of mitofusion/mitochondrial fusion by MOTS‐c following the onset of mitochondrial biogenesis. This was confirmed after a significant increase in protein levels two GTPases, OPA1, and MFN2, both vital for the fusion of mammalian mitochondria. Finally, we found that inhibition of the two GTPases by TNFα abrogated the ability of MOTS‐c to prompt GLUT4 translocation and glucose uptake. Similar results were obtained by siRNA KD of MFN2 as well. Our results reveal for the first time a pathway that links mitofusion to MOTS-c-induced GLUT4 translocation.

The Comparison of Eight Weeks of HIIT and BFR on Mitochondrial Biogenesis and Angiogenesis Markers in Vastus Lateralis Muscle of Amateur Male Runners

Background and Aims Post-exercise Blood Flow Restriction (BFR) is a novel training method that, through alterations to the haemodynamic, metabolic, and hypoxic stimulus, could augment skeletal muscle adaptation in endurance-trained individuals. This study aimed to compare the effect of eight weeks of High-Intensity Interval Training (HIIT) and BFR on PGC-1α and Vascular Endothelial Growth Factor (VEGF) as mitochondrial biogenesis and angiogenesis biomarkers, respectively, in amateur male runners. Methods In the current study, 15 runners (Meas±SD of age: 23±3 years; height: 172±5 cm; weight: 73±4 kg: BMI: 23±1.7 kg/m2) voluntarily participating in this study were divided into three groups: 1-Control 2-HIIT and 3-HIIT+BFR or BFR. The experimental groups performed three sessions a week (six trials each session) for eight weeks. The biopsy samples were collected from the vastus lateralis muscle at the first and end of eight weeks. The protein expression levels of the PGC-1α and VEGF were studied by immunohistochemical method. Data analysis was performed using the one-way Analysis of Covariance (ANCOVA), and a significance level of P&lt;0.05 was considered. Results The findings showed that PGC-1α values were significantly increased in the HIIT and BFR groups (54.9% and 60.85%, respectively) compared to the control group, as well as VEGF levels were 51.31% and 57.52%, respectively (P&lt;0.05). There were also significant differences between experimental groups in the protein expressions (P&lt;0.05). Conclusion Given that activation of VEGF from the PGC-1 pathway is part of cellular-molecular mechanisms of high-intensity interval training, It seems that the combination of intense interval training and BFR can effectively affect the process of angiogenesis in the vastus lateralis muscle of amateur runners.

Increased uterine androgen receptor protein abundance results in implantation and mitochondrial defects in pregnant rats with hyperandrogenism and insulin resistance

In this study, we show that during normal rat pregnancy, there is a gestational stage-dependent decrease in androgen receptor (AR) abundance in the gravid uterus and that this is correlated with the differential expression of endometrial receptivity and decidualization genes during early and mid-gestation. In contrast, exposure to 5α-dihydrotestosterone (DHT) and insulin (INS) or DHT alone significantly increased AR protein levels in the uterus in association with the aberrant expression of endometrial receptivity and decidualization genes, as well as disrupted implantation. Next, we assessed the functional relevance of the androgen-AR axis in the uterus for reproductive outcomes by treating normal pregnant rats and pregnant rats exposed to DHT and INS with the anti-androgen flutamide. We found that AR blockage using flutamide largely attenuated the DHT and INS-induced maternal endocrine, metabolic, and fertility impairments in pregnant rats in association with suppressed induction of uterine AR protein abundance and androgen-regulated response protein and normalized expression of several endometrial receptivity and decidualization genes. Further, blockade of AR normalized the expression of the mitochondrial biogenesis marker Nrf1 and the mitochondrial functional proteins Complexes I and II, VDAC, and PHB1. However, flutamide treatment did not rescue the compromised mitochondrial structure resulting from co-exposure to DHT and INS. These results demonstrate that functional AR protein is an important factor for gravid uterine function. Impairments in the uterine androgen-AR axis are accompanied by decreased endometrial receptivity, decidualization, and mitochondrial dysfunction, which might contribute to abnormal implantation in pregnant PCOS patients with compromised pregnancy outcomes and subfertility.Key messagesThe proper regulation of uterine androgen receptor (AR) contributes to anormal pregnancy process, whereas the aberrant regulation of uterine AR mightbe linked to polycystic ovary syndrome (PCOS)-induced pregnancy-relatedcomplications.In the current study, we found that during normal rat pregnancy there isa stage-dependent decrease in AR abundance in the gravid uterus and that thisis correlated with the differential expression of the endometrial receptivityand decidualization genes Spp1, Prl, Igfbp1,and Hbegf.Pregnant rats exposed to 5α-dihydrotestosterone (DHT) and insulin (INS)or to DHT alone show elevated uterine AR protein abundance and implantationfailure related to the aberrant expression of genes involved in endometrialreceptivity and decidualization in early to mid-gestation.Treatment with the anti-androgen flutamide, starting frompre-implantation, effectively prevents DHT + INS-induced defects in endometrialreceptivity and decidualization gene expression, restores uterine mitochondrialhomeostasis, and increases the pregnancy rate and the numbers of viablefetuses.This study adds to our understanding of the mechanisms underlying poorpregnancy outcomes in PCOS patients and the possible therapeutic use ofanti-androgens, including flutamide, after spontaneous conception.