PGC-1α Gene Research Articles

The effects of sodium butyrate supplementation on the expression levels of PGC-1α, PPARα, and UCP-1 genes, serum level of GLP-1, metabolic parameters, and anthropometric indices in obese individuals on weight loss diet: a study protocol for a triple-blind, randomized, placebo-controlled clinical trial

BackgroundObesity is a multifaceted disease characterized by an abnormal accumulation of adipose tissue. Growing evidence has proposed microbiota-derived metabolites as a potential factor in the pathophysiology of obesity and related metabolic conditions over the last decade. As one of the essential metabolites, butyrate affects several host cellular mechanisms related to appetite sensations and weight control. However, the effects of butyrate on obesity in humans have yet to be studied. Thus, the present study was aimed to evaluate the effects of sodium butyrate (SB) supplementation on the expression levels of peroxisome proliferator activated-receptor (PPAR) gamma coactivator-1α (PGC-1α), PPARα and uncoupling protein 1 (UCP1) genes, serum level of glucagon-like peptide (GLP1), and metabolic parameters, as well as anthropometric indices in obese individuals on a weight loss diet.MethodsThis triple-blind randomized controlled trial (RCT) will include 50 eligible obese subjects aged between 18 and 60 years. Participants will be randomly assigned into two groups: 8 weeks of SB (600 mg/day) + hypo-caloric diet or placebo (600 mg/day) + hypo-caloric diet. At weeks 0 and 8, distinct objectives will be pursued: (1) PGC-1α, PPARα, and UCP1 genes expression will be evaluated by real-time polymerase chain reaction; (2) biochemical parameters will be assayed using enzymatic methods; and (3) insulin and GLP1 serum level will be assessed by enzyme-linked immunosorbent assay kit.DiscussionNew evidence from this trial may help fill the knowledge gap in this realm and facilitate multi-center clinical trials with a substantially larger sample size.Trial registrationIranian Registry of Clinical Trials: IRCT20190303042905N2. Registered on 31 January 2021.

Epicardial and visceral adipose tissue expression levels of MIR-1247-5P and PGC-1Α gene are associated with obesity

Epicardial and visceral adipose tissue expression levels of MIR-1247-5P and PGC-1Α gene are associated with obesity

Role of DNA methylation during recovery from spinal cord injury with and without β2-adrenergic receptor agonism

Daily treatment with the FDA-approved β2-adrenergic receptor agonist formoterol beginning 8 h after severe spinal cord injury (SCI) induces mitochondrial biogenesis and improves recovery in mice. We observed decreased DNA methyltransferase (DNMT) expression, global DNA methylation and methylation of the mitochondrial genes PGC-1α and NDUFS1 in the injury site of formoterol-treated mice 1 DPI, but this effect was lost by 7 DPI. To investigate the role of DNA methylation on recovery post-SCI, injured mice were treated daily with formoterol or vehicle, plus the DNMT inhibitor decitabine (DAC) on days 7–9. While DAC had no apparent effect on formoterol-induced recovery, mice treated with vehicle plus DAC exhibited increased BMS scores compared to vehicle alone beginning 15 DPI, reaching a degree of functional recovery similar to that of formoterol-treated mice by 21 DPI. Furthermore, DAC treatment increased injury site mitochondrial protein expression in vehicle-treated mice to levels comparable to that of formoterol-treated mice. The effect of DNMT inhibition on pain response with and without formoterol was assessed following moderate SCI. While all injured mice not treated with DAC displayed thermal hyperalgesia by 21 DPI, mice treated with formoterol exhibited decreased thermal hyperalgesia compared to vehicle-treated mice by 35 DPI. Injured mice treated with DAC, regardless of formoterol treatment, did not demonstrate thermal hyperalgesia at any time point assessed. Although these data do not suggest enhanced formoterol-induced recovery with DNMT inhibition, our findings indicate the importance of DNA methylation post-SCI and support both DNMT inhibition and formoterol as potential therapeutic avenues.

Cathepsin S deficiency improves muscle mass loss and dysfunction via the modulation of protein metabolism in mice under pathological stress conditions.

Cathepsin S (CTSS) is a widely expressed cysteinyl protease that has garnered attention because of its enzymatic and non-enzymatic functions under inflammatory and metabolic pathological conditions. Here, we examined whether CTSS participates in stress-related skeletal muscle mass loss and dysfunction, focusing on protein metabolic imbalance. Eight-week-old male wildtype (CTSS+/+ ) and CTSS-knockout (CTSS-/- ) mice were randomly assigned to non-stress and variable-stress groups for 2 weeks, and then processed for morphological and biochemical studies. Compared with non-stressed mice, stressed CTSS+/+ mice showed significant losses of muscle mass, muscle function, and muscle fiber area. In this setting, the stress-induced harmful changes in the levels of oxidative stress-related (gp91phox and p22phox ,), inflammation-related (SDF-1, CXCR4, IL-1β, TNF-α, MCP-1, ICAM-1, and VCAM-1), mitochondrial biogenesis-related (PPAR-γ and PGC-1α) genes and/or proteins and protein metabolism-related (p-PI3K, p-Akt, p-FoxO3α, MuRF-1, and MAFbx1) proteins; and these alterations were rectified by CTSS deletion. Metabolomic analysis revealed that stressed CTSS-/- mice exhibited a significant improvement in the levels of glutamine metabolism pathway products. Thus, these findings indicated that CTSS can control chronic stress-related skeletal muscle atrophy and dysfunction by modulating protein metabolic imbalance, and thus CTSS was suggested to be a promising new therapeutic target for chronic stress-related muscular diseases.

Hyperbaric oxygen and treadmill exercise partially prevented bone loss and bone microarchitecture deterioration in ovariectomized rats.

Previous studies have demonstrated the beneficial effects of treadmill exercise (EX) on osteoporosis, and of hyperbaric oxygen (HBO) on osteoblast and osteoclast formation in vitro. We investigated the effects of HBO and the combination of HBO and EX on osteoporosis in ovariectomized rats. Forty 3-month-old female Sprague-Dawley rats were randomly divided into 5 groups (n = 8): a sham control group (Control); an ovariectomy group; an ovariectomy with treadmill exercise treatment group; an ovariectomy with HBO treatment group; and an ovariectomy with HBO treatment combined with treadmill exercise group. The HBO exposures were 203 kPa, 85-90% O₂, 90 min and the exercise regimen was 20 m·min⁻¹, 40 min·day¹, 5° slope. Both treatments were administered once daily, five days a week for 12 weeks until the rats were sacrificed. All three treatments (HBO, exercise, and both combined) significantly promoted the expression of the osteoblast-related gene and oxidative metabolism-related gene (PGC-1α). They also exerted significant inhibitory effects on the osteoclast-related mRNA expression (RANKL) and bone resorption marker CTX-I. Additionally, exercise and the combination exercise-HBO treatment increased serum superoxide dysmutase (SOD) and sclerostin expression. No significant between-group difference was observed. Hyperbaric oxygen, exercise, and the combination ameliorated bone microarchitecture deterioration and ovariectomy-induced bone loss in rats, and these inhibitory effects may be associated with the increased SOD and up-regulated PGC-1α.

Sex and age differences in AMPK phosphorylation, mitochondrial homeostasis, and inflammation in hearts from inflammatory cardiomyopathy patients.

Linked to exacerbated inflammation, myocarditis is a cardiovascular disease, which may lead to dilated cardiomyopathy. Although sex and age differences in the development of chronic myocarditis have been postulated, underlying cellular mechanisms remain poorly understood. In the current study, we aimed to investigate sex and age differences in mitochondrial homeostasis, inflammation, and cellular senescence. Cardiac tissue samples from younger and older patients with inflammatory dilated cardiomyopathy (DCMI) were used. The expression of Sirt1, phosphorylated AMPK, PGC-1α, Sirt3, acetylated SOD2, catalase, and several mitochondrial genes was analyzed to assess mitochondrial homeostasis. The expression of NF-κB, TLR4, and interleukins was used to examine the inflammatory state in the heart. Finally, several senescence markers and telomere length were investigated. Cardiac AMPK expression and phosphorylation were significantly elevated in male DCMI patients, whereas Sirt1 expression remained unchanged in all groups investigated. AMPK upregulation was accompanied by a preserved expression of all mitochondrial proteins/genes investigated in older male DCMI patients, whereas the expression of TOM40, TIM23, and the mitochondrial oxidative phosphorylation genes was significantly reduced in older female patients. Mitochondrial homeostasis in older male patients was further supported by the reduced acetylation of mitochondrial proteins as indicated by acetylated SOD2. The inflammatory markers NF-κB and TLR4 were downregulated in older male DCMI patients, whereas the expression of IL-18 was increased in older female patients. This was accompanied by progressed senescence in older DCMI hearts. In conclusion, older women experience more dramatic immunometabolic disorders on the cellular level than older men.

Effects of aerobic training and vitamin D supplementation on glycemic indices and adipose tissue gene expression in type 2 diabetic rats

Type 2 diabetes mellitus (T2DM) is a progressive metabolic disorder mainly caused by overweight and obesity that accumulates pro-inflammatory factors in adipose tissue. Studies have confirmed the efficacy of exercise and vitamin D supplementation in preventing, controlling, and treating diabetes. While, reduced physical activity and vitamin D deficiency are related to increased adiposity, blood glucose level, insulin concentration, and insulin resistance. This study purposed to investigate the effect of 8-week aerobic training with vitamin D supplementation on the expression of AMPK, PGC-1α, and UCP-1 genes expression in the visceral adipose tissue of obese rats with T2DM. In this experimental study, fifty male Wistar rats were divided into 5 groups (n = 10): aerobic training and vitamin D supplementation (AT + Vit D), aerobic training (5 days/week for 8 weeks; AT), vitamin D supplementation (Vit D), diabetic control (C) and NC (Non-Diabetic Control). AT + Vit D and AT groups practiced an 8-week aerobic training, 5 days a week. Vit D and AT + Vit D groups receive 5000 IU of vitamin D by injection once a week while AT and C received sesame oil. After blood sampling, visceral fat was taken to measure AMPK, PGC-1α, and UCP1 gene expression. Data were statistically analyzed by One-way ANOVA and paired sample t-test at a significance level of p < 0.05. Based on our results BW, BMI, WC, visceral fat, insulin, glucose, and HOMA-IR were significantly lower in the AT + Vit D, AT, and Vit D groups compared with the C group (p < 0.01). Furthermore, AT + Vit D, AT, and Vit D upregulated AMPK, PGC-1α, and UCP1 gene expression compared to the C. Based on the results compared to AT and Vit D, AT + Vit D significantly upregulated AMPK (p = 0.004; p = 0.001), PGC-1α (p = 0.010; p = 0.001), and UCP1 (p = 0.032; p = 0.001) gene expression, respectively. Also, AT induced more significant upregulations in the AMPK (p = 0.001), PGC-1α (p = 0.001), and UCP1 gene expression (p = 0.001) than Vit D. Vitamin D supplementation enhanced the beneficial effects of aerobic training on BW, BMI, WC, visceral fat, insulin, glucose, and HOMA-IR in diabetic rats. We also observed that separate AT or Vit D upregulated the gene expression of AMPK, PGC-1α, and UCP1 however, combined AT + Vit D upregulated AMPK, PGC-1α, and UCP1 more significantly. These results suggested that combining aerobic training and vitamin D supplementation exerted incremental effects on the gene expressions related to adipose tissue in animal models of diabetes.

Metformin Disrupts Signaling and Metabolism in Fetal Hepatocytes.

The major metformin uptake transporter OCT1 is expressed in the fetal liver, and fetal hepatic uptake of metformin is observed invivo. Metformin activates AMPK, reduces glucose production, and decreases oxygen consumption in fetal hepatocytes, demonstrating similar effects as in juvenile hepatocytes. Unique to fetal hepatocytes, metformin activates metabolic stress pathways and alters the expression of secreted growth factors and hepatokines. Disruption of signaling and metabolism with increased stress pathways and reduced anabolic pathways by metformin in the fetal liver may underlie reduced growth in fetuses exposed to metformin.

Naringenin ameliorates vascular senescence and atherosclerosis involving SIRT1 activation.

This study was to explore the potential effects and mechanism of naringenin against vascular senescence in atherosclerosis focusing on the SIRT1-mediated signalling pathway. Aged apoE-/- mice were administrated with naringenin continuously for three months. Lipid parameters in serum and pathological changes and associated protein expression in aorta were examined. In vitro, endothelial cells were treated with H2O2 to induce senescence. Dyslipidemia, atherosclerotic lesion formation and vascular senescence were found in ApoE-/- mice, which were significantly ameliorated by naringenin treatment. Naringenin decreased reactive oxygen species overproduction and enhanced the activities of antioxidant enzymes in aorta. It also decreased mitoROS production and increased protein expressions of mitochondrial biogenesis-related genes in aorta. Moreover, naringenin treatment enhanced aortic protein expression and activity of SIRT1. Meanwhile, naringenin increased deacetylation and protein expression of SIRT1's target genes FOXO3a and PGC1α. In vitro study, the benefits of naringenin on endothelial senescence, oxidative stress and mitochondrial injury as well as protein expressions and acetylated levels of FOXO3a and PGC1α were diminished in cells transfected with SIRT1 siRNA. Naringenin could ameliorate vascular senescence and atherosclerosis and the activation of SIRT1, with subsequent deacetylation and regulation of FOXO3a and PGC1α, is involved in this process.

Peroxisome proliferator-activated receptor gamma (PPARγ) activation: a potential treatment for ascites syndrome in broiler chickens

Ascites (serous fluid accumulation in the abdominal cavity) has been observed worldwide in fast growing broilers. Pulmonary vascular remodeling is an important pathological feature of broiler ascites syndrome. Peroxisome proliferators-activated receptor gamma (PPARγ) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) are expressed in pulmonary vascular endothelial cells and vascular smooth muscle cells (VSMC) where they participate in the regulation of normal pulmonary vascular function. The objective of the present study was to investigate the effects of omega-3 fatty acids (found in fish oil) and pioglitazone (PIO) as natural and synthetic PPARγ ligands supplementation on PPARγ and PGC-1α expression in the prevention of pulmonary arterial hypertension (PAH) syndrome in broiler chickens. The experiment was conducted with 4 treatment groups: 1) negative control, normal temperature conditions with basal diet; 2) positive control, low-temperature conditions with basal diet; 3) positive control+10 mg PIO/kg of weight/d and 4) positive control+1% FO. Each treatment had 5 replicates. Ascites heart index (RV/TV) was significantly (P < 0.05) reduced in chickens receiving FO (0.20) and PIO (0.21) compared to the positive control group (0.26). The addition of PIO in broilers under cold-induced ascites significantly increased the expression of PPARγ (9.44) and PGC-1α (5.81) genes in lung tissue compared to the negative control group (1.03, P < 0.05). Proliferative indexes of VSMC in pulmonary arteries such as PMT, PIT, and percentage wall thickness were significantly elevated in positive control group, indicating that pulmonary vascular remodeling occurred following VSMC proliferation in ascites. The vessel internal diameter was increased in FO and PIO groups. Based on these results, activation and expression of PPARγ and PGC-1α genes as a critical regulator of pulmonary artery smooth muscle cell using ligands, especially PIO, can be effective in reducing the incidence of PAH in broiler chickens.

Whole Grain Proso Millet (Panicum miliaceum L.) Attenuates Hyperglycemia in Type 2 Diabetic Mice: Involvement of miRNA Profile.

This work aimed to investigate the hypoglycemic effects and underlying mechanism of whole grain proso millet (Panicum miliaceum L.; WPM) on type 2 diabetes mellitus (T2DM). The results showed that WPM supplementation significantly reduced fasting blood glucose (FBG) and serum lipid levels in T2DM mice induced by a high-fat diet (HFD) combined with streptozotocin (STZ), with improved glucose tolerance, liver and kidney injury, and insulin resistance. In addition, WPM significantly inhibited the expression of gluconeogenesis-related genes G6pase, Pepck, Foxo1, and Pgc-1α. Further study by miRNA high-throughput sequencing revealed that WPM supplementation mainly altered the liver miRNA expression profile of T2DM mice by increasing the expression of miR-144-3p_R-1 and miR-423-5p, reducing the expression of miR-22-5p_R-1 and miR-30a-3p. GO and KEGG analyses showed that the target genes of these miRNAs were mainly enriched in the PI3K/AKT signaling pathway. WPM supplementation significantly increased the level of PI3K, p-AKT, and GSK3β in the liver of T2DM mice. Taken together, WPM exerts antidiabetic effects by improving the miRNA profile and activating the PI3K/AKT signaling pathway to inhibit gluconeogenesis. This study implies that PM can act as a dietary supplement to attenuate T2DM.

Effect of DNA damage mediating psychosocial stress on aging

Adversity and psychosocial stress are involved in aging through the following pathways. psychological stress enhances the nerve system to secrete endocrine mediators (hormones). Mitochondrial respiration mediates energy production stimulated by binding to these hormones to their receptors. Energy produced by mitochondria accelerates metabolism and, in its turn, leads to increases in reactive oxygen species (ROS) of free radicals. Cellular stress and accumulation of damage can result from an excess of ROS. Accumulation of damage comprises damages in telomeric and nontelomeric DNA, in addition to mitochondrial DNA. Mitochondrial DNA damage plays an important role in increasing the pathway of p53/p21. The expression of the PGC-1α gene is inhibited by activation of the previous pathway that generates a decrease in mitochondrial biogenesis. The low level of mitochondrial biogenesis generates mitophagy defects and increases the level of dysfunctional mitochondria that lead to a high level of ROS production. Nuclear DNA damage and mitochondrial dysfunction stimulate necrosis or cell senescence. Necrotic cells enhance the inflammatory activity by which damage-associated molecular patterns (DAMPs) are continuously secreted. Senescent cells secrete high levels of the senescence-associated secretory phenotype (SASP) that includes tumor necrosis factor TNF-α and interleukin-6 (IL-6) as inflammatory cytokines, and MCP-2 and interleukin-8 (IL-8) as chemokines. All these processes work together to accelerate the biological aging process by causing defects related to aging such as diabetes and cardiovascular disease.

Lipid nanoparticle delivery of siRNA targeting Cyp2e1 gene attenuates subacute alcoholic liver injury in mice.

To investigate the effect and mechanism of lipid nanoparticle (LNP) delivery of small interfering RNA (siRNA) targeting Cyp2e1 gene on subacute alcoholic liver injury in mice. siRNA targeting Cyp2e1 gene was encapsulated in LNP (si-Cyp2e1 LNP) by microfluidic technique and the resulting LNPs were characterized. The optimal dose of si-Cyp2e1 LNP administration was screened. Forty female C57BL/6N mice were randomly divided into blank control group, model control group, si-Cyp2e1 LNP group, LNP control group and metadoxine group. The subacute alcoholic liver injury mouse model was induced by ethanol feeding for 10 d plus ethanol gavage for the last 3 d. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, and the superoxide dismutase (SOD) activity as well as malondialdehyde, reactive oxygen species, glutathione, triacylglycerol, total cholesterol contents in liver tissue were measured in each group, and liver index was calculated. The expression of genes related to oxidative stress, lipid synthesis and inflammation in each group of mice were measured by realtime RT-PCR. Compared with the model control group, the levels of liver index, serum ALT, AST activities, malondialdehyde, reactive oxygen species, triacylglycerol, total cholesterol contents in liver tissue decreased, but the SOD activity as well as glutathione increased in the si-Cyp2e1 LNP group (all P<0.01). Hematoxylin-eosin staining result showed disorganized hepatocytes with sparse cytoplasm and a large number of fat vacuoles and necrosis in the model control group, while the si-Cyp2e1 LNP group had uniformly sized and arranged hepatocytes with normal liver tissue morphology and structure. Oil red O staining result showed si-Cyp2e1 LNP group had lower fat content of the liver compared to the model control group (P<0.01), and no fat droplets accumulated. Anti-F4/80 monoclonal antibody fluorescence immunohistochemistry showed that the si-Cyp2e1 LNP group had lower cumulative optical density values compared to the model control group (P<0.01) and no significant inflammatory reaction. Compared with the model control group, the expression of catalytic genes P47phox, P67phox and Gp91phox were reduced (all P<0.01), while the expression of the antioxidant enzyme genes Sod1, Gsh-rd and Gsh-px were increased (all P<0.01). The mRNA expression of the lipid metabolism genes Pgc-1α and Cpt1 were increased (all P<0.01) and the lipid synthesis-related genes Srebp1c, Acc and Fasn were decreased (all P<0.01); the expression of liver inflammation-related genes Tgf-β, Tnf-α and Il-6 were decreased (all P<0.01). The si-Cyp2e1 LNP may attenuate subacute alcoholic liver injury in mice mainly by reducing reactive oxygen levels, increasing antioxidant activity, blocking oxidative stress pathways and reducing ethanol-induced steatosis and inflammation.

Loss of Brain Angiogenesis Inhibitor-3 (BAI3) G-Protein Coupled Receptor in Mice Regulates Adaptive Thermogenesis by Enhancing Energy Expenditure.

Effective energy expenditure is critical for maintaining body weight (BW). However, underlying mechanisms contributing to increased BW remain unknown. We characterized the role of brain angiogenesis inhibitor-3 (BAI3/ADGRB3), an adhesion G-protein coupled receptor (aGPCR), in regulating BW. A CRISPR/Cas9 gene editing approach was utilized to generate a whole-body deletion of the BAI3 gene (BAI3-/-). In both BAI3-/- male and female mice, a significant reduction in BW was observed compared to BAI3+/+ control mice. Quantitative magnetic imaging analysis showed that lean and fat masses were reduced in male and female mice with BAI3 deficiency. Total activity, food intake, energy expenditure (EE), and respiratory exchange ratio (RER) were assessed in mice housed at room temperature using a Comprehensive Lab Animal Monitoring System (CLAMS). While no differences were observed in the activity between the two genotypes in male or female mice, energy expenditure was increased in both sexes with BAI3 deficiency. However, at thermoneutrality (30 °C), no differences in energy expenditure were observed between the two genotypes for either sex, suggesting a role for BAI3 in adaptive thermogenesis. Notably, in male BAI3-/- mice, food intake was reduced, and RER was increased, but these attributes remained unchanged in the female mice upon BAI3 loss. Gene expression analysis showed increased mRNA abundance of thermogenic genes Ucp1, Pgc1α, Prdm16, and Elov3 in brown adipose tissue (BAT). These outcomes suggest that adaptive thermogenesis due to enhanced BAT activity contributes to increased energy expenditure and reduced BW with BAI3 deficiency. Additionally, sex-dependent differences were observed in food intake and RER. These studies identify BAI3 as a novel regulator of BW that can be potentially targeted to improve whole-body energy expenditure.

Paternal Aggression in Early-life Impairs the Spatial Memory and Passive Avoidance Learning in Adulthood of Male Rats: The Possible Role of DRD2

Introduction: Negative early-life experiences (e.g. having an aggressive father) can leave long-lastingimpacts on the behavior. However, it is not clear if they influence learning and memory. Methods: In this study, we investigated the influences that the presence of an aggressive father had on the level of passive avoidance learning and spatial memory. We also studied the changes in the dopamine receptor D2 (DRD2) and peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) gene expression in the hippocampus. Then, we evaluated if a DRD2 antagonist (sulpiride, 0.125, 0.25, or 0.5 μg/rat) could modulate these changes. Results: We found that the subjects exposed to early-life stress made by aggressive fathers had impaired passive avoidance learning and spatial memory compared to subjects with normal fathers. Treatment with sulpiride improved passive avoidance learning and spatial memory in rats with aggressive fathers. The rats with aggressive fathers also had higher expression of the DRD2 gene in their hippocampus than those with normal fathers, while the PGC-1α gene expression was not different among groups. Treatment with sulpiride (0.125, 0.25, or 0.5 μg/rat) reduced the DRD2 gene expression in those with aggressive fathers to the normal level compared to those with normal fathers. Conclusion: These data suggest that having and living in a shared place with an aggressive father, even without any physical contact, can detrimentally affect passive avoidance learning and spatial memory which is accompanied by the increased expression of the DRD2 gene. Also, sulpiride as a dopaminergic antagonist could reverse this process.

The Role of Acetyl-CoA Synthetase Short Chain Family Member-1 on Adipocyte Thermogenic Capacity

Obesity is characterized by an increase in adipose mass and is the leading risk factor for type 2 diabetes. Recent research suggests that activation of brown or beige fat and white adipose tissue browning represent a new therapeutic strategy for metabolic diseases. Fatty acid oxidation is required for the browning of white adipose tissue (WAT) and the induction of uncoupling protein 1 (UCP1) in WAT. The Acyl-CoA Synthetase Short Chain Family Member-1 (ACSS1), an established SIRT3 deacetylation target, is central to fatty acid oxidation (FAO) and mitochondrial bioenergetics by converting acetate and CoA to acetyl-CoA. However, the biological function of ACSS1 acetylation (ACSS1-Ac) in thermogenic adipose tissue and how it contributes to metabolic changes in adipocytes has not been investigated. We have generated a novel acetylation mimic mouse where lysine 635 (K635) was mutated to glutamine (K635Q), representing constitutive ACSS1-K635-Ac. Male mice expressing Acss1 K635Q/K635Q exhibited a reduction in size and body weight. Upon 48-hour fasting, these mice exhibited hypothermia as well as decreased ATP and lactate levels. Interestingly, UCP1 gene expression was upregulated in brown adipose tissue (BAT) of the Acss1 K635Q/K635Q compared to WT and also in WAT from fasted animals. Differentiated beige adipocytes also showed higher UCP1, PGC1a and adiponectin gene expression in cells isolated from Acss1 K635Q/K635Q mice compared to WT cells. Oxygen consumption rate of these cells was lower with lower basal and ATP-coupled respiration. Acss1 K635Q/K635Q beige adipocytes failed to respond to beta-adrenergic stimulation and did not increase their respiration capacity when compared to WT cells. No differences were observed in glucose uptake and lipolysis functional assays. These results suggest that the mutation leads to a disruption of downstream signaling of UCP1. In conclusion, ACSS1-K635-Ac is a novel thermoregulator in adipose tissue that could lead to further development of new therapies for metabolic diseases. 1. Mays Cancer Center CCSG (P30 CA054174); 2. National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health, under Award Number F32-0DK122754 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Silicon dioxide nanoparticles inhibit the effects of cold exposure on metabolism and inflammatory responses in brown adipocytes

Abstract Objective Nanoparticles (NPs) in haze are potentially hazardous to health, which is more severe in the winter. Brown adipose tissue (BAT) plays important roles in obesity, insulin resistance, and diabetes. Though the toxicology of NPs has been intensively studied, few studies have been reported on the antagonistic effects between Silicon dioxide(SiO2) NPs and cold exposure in brown adipocytes. Materials and methods We evaluated changes by quantitative real-time reverse-transcriptase polymerase chain reaction (qRT-PCR) on metabolism genes, plasticity genes and the inflammatory responses genes in brown adipocytes in vitro. Results The expression of adipogenic genes PRDM16, Dio2, PGC-1α and UCP1 was upregulated upon cold exposure (P &lt; 0.05), but downregulated by SiO2 NPs (P &lt; 0.05). The results demonstrated that there was antagonistic effect between SiO2 NPs and cold exposure on the plasticity genes and metabolism genes in brown adipocytes, where the main effects of SiO2 NPs or cold exposure on the plasticity genes and metabolism genes were significant (P &lt; 0.05). Moreover, the levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α were upregulated by SiO2 NPs or cold exposure (P &lt; 0.05). The factorial analysis indicated that there was also antagonistic effect between SiO2 NPs and cold exposure on the toxic effects in brown adipocytes, in which the main effects of cold exposure and/or SiO2 NPs on the toxic effects were significant (P &lt; 0.05). Conclusion SiO2 NPs inhibit the effect of cold exposure on metabolic genes and inflammatory responses genes in brown adipocytes.

Glucagon Promotes Gluconeogenesis through the GCGR/PKA/CREB/PGC-1α Pathway in Hepatocytes of the Japanese Flounder Paralichthys olivaceus.

In order to investigate the mechanism of glucagon regulation of gluconeogenesis, primary hepatocytes of the Japanese flounder (Paralichthys olivaceus) were incubated with synthesized glucagon, and methods based on inhibitors and gene overexpression were employed. The results indicated that glucagon promoted glucose production and increased the mRNA levels of glucagon receptor (gcgr), guanine nucleotide-binding protein Gs α subunit (gnas), adenylate cyclase 2 (adcy2), protein kinase A (pka), cAMP response element-binding protein 1 (creb1), peroxisome proliferator-activated receptor-γ coactivator 1α (pgc-1α), phosphoenolpyruvate carboxykinase 1 (pck1), and glucose-6-phosphatase (g6pc) in the hepatocytes. An inhibitor of GCGR decreased the mRNA expression of gcgr, gnas, adcy2, pka, creb1, pgc-1α, pck1, g6pc, the protein expression of phosphorylated CREB and PGC-1α, and glucose production. The overexpression of gcgr caused the opposite results. An inhibitor of PKA decreased the mRNA expression of pgc-1α, pck1, g6pc, the protein expression of phosphorylated-CREB, and glucose production in hepatocytes. A CREB-targeted inhibitor significantly decreased the stimulation by glucagon of the mRNA expression of creb1, pgc-1α, and gluconeogenic genes, and glucose production decreased accordingly. After incubating the hepatocytes with an inhibitor of PGC-1α, the glucagon-activated mRNA expression of pck1 and g6pc was significantly down-regulated. Together, these results demonstrate that glucagon promotes gluconeogenesis through the GCGR/PKA/CREB/PGC-1α pathway in the Japanese flounder.

Bone Marrow-Derived Mesenchymal Stem Cells and Pioglitazone or Exendin-4 Synergistically Improve Insulin Resistance via Multiple Modulatory Mechanisms in High-Fat Diet/Streptozotocin-Induced Diabetes in Rats.

Diabetes mellitus (DM) is a metabolic disease, characterized by hyperglycemia resulting from defects in insulin secretion and/or insulin action. The current study was designed to assess the therapeutic potential of bone marrow-derived mesenchymal stem cells (BM-MSCs) alone and in combination with pioglitazone (Pz) or exendin-4 (Ex) in high-fat diet/streptozotocin (HFD/STZ)-induced diabetes in rats. The rats were subjected to the HFD for three weeks before being injected with a single low dosage of STZ (35 mg/kg bw). The animals were assigned to different treatment groups after type II diabetes mellitus (T2DM) induction was confirmed. Severe insulin resistance was verified in untreated HFD/STZ T2DM rats, along with the exaggeration of oxidative stress, inflammation, apoptosis, and autophagy suppression in the adipose tissues. Monotherapy of HFD/T2DM rats with BM-MSCs and Pz or Ex alleviated diabetic complications by increasing insulin sensitivity, decreasing apoptosis and inflammation as evidenced by a decrease in serum tumor necrosis factor-alpha, caspase-3, and nuclear factor-kappa B (NF-κB) genes expression and Janus kinase (JNK) protein expression, and enhancing autophagy as revealed by upregulation in beclin and LC3, as well as peroxisome proliferator-activated receptor-γ coactivator-1 alpha (PGC-1α) genes expression in the adipose tissues. An augmented ameliorative efficacy was recorded in combined treatments. The biochemical and molecular results were confirmed by histological investigation of pancreatic tissues. Combining Pz or Ex with BM-MSCs is a synergistic therapeutic option that reduces insulin resistance and subsequent complications in T2DM via multiple molecular mechanisms.

Fenofibrate mildly stimulates browning-associated expression in white adipose tissues of young but not old male rats.

The aim of this study was to examine the effects of the hypolipemic drug fenofibrate (FF) and aging on the expression of factors/enzymes involved in brown adipose tissue (BAT) function and browning of white adipose tissue epididymal (eWAT) and subcutaneous (sWAT) depots. Young-adult and old male Wistar rats were fed standard chow (control) or supplemented with 0.1% or 0.5% FF for 30 days. Tissue samples were analysed for gene expression and protein content, and stained with Oil Red O or hematoxylin and eosin. In BAT of young rats, 0.5% FF increased only Cbp/p300 interacting transactivator with Glu/Asp rich carboxy-terminal domain 1 (CITED1) protein content and Fgf21 and Gpr109A mRNA expression. The expression of oxidative metabolism related genes (Pgc1α, Cpt1b, Mcad) decreased after 0.5% FF. In BAT of old rats, FF did not affect UCP1 and CITED1 content and had little effect on gene expression. Oil Red O staining of BAT revealed no changes in lipid droplet area upon treatment in either age group. In eWAT of young rats, 0.1FF elevated UCP1 protein content and Ucp1, Pgc-1α, and Mcad expression, whereas 0.5% FF increased PPARα content and Pgc-1α, Cpt1b, Mcad, and Gpr109A levels. In eWAT of old rats, only 0.1FF increased Pgc1α and Mcad expression. In both age groups median cell area of eWAT adipocytes was reduced after 0.5% FF. In sWAT Ucp1 gene expression was very low and UCP1 protein was undetectable. FF upregulated Ucp1, Cited1, Eva1, and Cpt1b expression in sWAT of young rats, with diminished effects in old rats. In both age groups 0.5% FF increased Fgf21 expression in sWAT. Median cell area of sWAT adipocytes decreased only in young rats treated with 0.5% FF. Our results reveal that fenofibrate differentially affects gene expression in BAT, with diminished effects in old compared to young rats. In WAT of young rats FF modestly stimulates the expression of factors/enzymes involved in lipid oxidative metabolism and browning. Aging reduces both these effects. Gpr109A may present a novel gene target upregulated by FF in BAT and eWAT.