A cold-inducible coactivator of nuclear receptors linked to adaptive thermogenesis

Understanding the peroxisome proliferator-activated receptor gamma (PPAR-γ) role in periodontitis and diabetes mellitus: A molecular perspective

Periodontitis and Type 2 Diabetes Mellitus (T2DM) are chronic conditions with dysregulated immune responses. Periodontitis involves immune dysfunction and dysbiotic biofilms, leading to tissue destruction. T2DM is marked by insulin resistance and systemic inflammation, driving metabolic and tissue damage. Both conditions share activation of key pathways, including Nuclear Factor Kappa B (NF-κB), Activator Protein-1 (AP-1), and Signal Transducer and Activator of Transcription (STAT) proteins, reinforcing an inflammatory feedback loop. This review highlights the role of Peroxisome Proliferator-Activated Receptor Gamma (PPAR-γ), a transcription factor central to lipid and glucose metabolism, adipogenesis, and immune regulation. PPAR-γ activation has been shown to suppress inflammatory mediators such as Tumor Necrosis Factor Alpha (TNF-α) and Interleukin 6 (IL-6) through the inhibition of NF-κB, AP-1, and STAT pathways, thereby potentially disrupting the inflammatory-metabolic cycle that drives both diseases. PPAR-γ agonists, including thiazolidinediones (TZDs) and endogenous ligands such as 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), show promise in reducing inflammation and improving insulin sensitivity, but they are limited by adverse effects. Therapies, including Selective Peroxisome Proliferator-Activated Receptor Modulators (SPPARMs), have been developed to offer a more targeted approach, allowing for selective modulation of PPAR-γ activity to retain its anti-inflammatory benefits while minimizing their side effects. By integrating insights into PPAR-γ's molecular mechanisms, this review underscores its therapeutic potential in mitigating inflammation and enhancing metabolic control.

Loss of PGC-1α causes depot-specific alterations in mitochondrial capacity, ROS handling and adaptive responses to metabolic stress in white adipose tissue

White adipose tissue (WAT) delivers lipid-fueled metabolic support to systemic energy expenditure through control of lipolytic and re-esterifying regulatory pathways, facilitated by mitochondrial bioenergetic support. Mitochondria are important sources of reactive oxygen species (ROS) and oxidative damage may potentially derail adipocyte function when mitochondrial homeostasis is challenged by overproduction of ROS. Peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1α is a transcriptional co-activator that in skeletal muscle plays a central role in mitochondrial biogenesis and function but whether PGC-1α is equally important for mitochondrial function and adaptations in white adipose tissue remains to be fully resolved. The aim of the present study was to characterize the necessity of adipocyte PGC-1α for adaptive regulation of mitochondrial function in distinct white adipose depots. PGC-1α adipose tissue-specific knockout (ATKO) and floxed littermate control mice (CTRL) were subjected to either 24 h of fasting or 48 h of cold exposure. Bioenergetics, ROS handling, basal and adaptive protein responses, markers of protein damage as well as lipid cycling capacity and regulation were characterized in distinct WAT depots. ATKO mice demonstrated impairments in respiration as well as reduced OXPHOS protein content in fed and fasted conditions. Increased ROS emission in tandem with diminished mitochondrial antioxidant defense capacity resulted in increased protein oxidation in ATKO WAT. Adipose tissue PGC-1α knockout also led to changes in regulation of lipolysis and potentially triglyceride reesterification in WAT. In conclusion, PGC-1α regulates adipose tissue mitochondrial respiration and ROS balance as well as lipid cycling during metabolic challenges in a depot specific manner.

Exosome miR-152-3p derived from small intestinal epithelium modulates aging process in adipocytes

Exosomes play a crucial role in facilitating intracellular communication between cells and tissues. The small intestine epithelium secretes exosomes, which is involved in various physiologic and pathologic processes. In this study, we investigated the effects of exosomal miR-152-3p derived from small intestinal epithelium on the aging process of adipocytes and its potential downstream mechanism. The exosomes derived from small intestinal epithelial cells were identified and characterized by TEM, NTA, and Western blot (WB). CCK-8 assay demonstrated the concentration-dependently increased 3T3-L1 cell viability by exosomes. PCR, Mito-Tracker red and DCFH-DA staining demonstrated the increased mtDNA content, mitochondrial activity, and the declined ROS content in 3T3-L1 adipocytes co-cultured with young exosomes. WB, PCR, β-galactosidase staining and ELISA demonstrated that the senescence was suppressed, uncoupling protein 1 (UCP1) and PPARgamma coactivator 1-alpha (PGC-1α) expression were upregulated, the levels of proinflammatory tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) were decreased in 3T3-L1 adipocytes co-cultured with young exosomes. Luciferase reporter assay determined the binding between miR-152-3p and PGC-1α. WB and PCR manifested that miR-152-3p was lowly expressed in young exosomes and miR-152-3p could decrease PGC-1α expression and increase the expression of senescence-related genes. Moreover, ITT and GTT and H&E staining in in vivo elderly mouse model demonstrated that miR-152-3p inhibitor decreased visceral fat, improved glucose tolerance and insulin sensitivity and inhibited aging. WB and PCR suggested that miR-152-3p inhibitor enhanced PGC-1α expression, suppressed the expression of senescence-related genes and proinflammatory factors in vivo. In summary, intestinal exosomes affect the browning function of adipocytes through miR-152-3p, modulating the aging process.

Acyl CoA-binding protein in brown adipose tissue acts as a negative regulator of adaptive thermogenesis

OBJECTIVE

Defective activity of brown adipose tissue (BAT) is linked to obesity and cardiometabolic diseases. While much is known regarding the biological signals that trigger BAT thermogenesis, relatively little is known about the repressors that may impair BAT function in physiological and pathological settings. Acyl CoA-binding protein (ACBP; also known as diazepam binding inhibitor, DBI) has intracellular functions related to lipid metabolism and can be secreted to act as a circulating regulatory factor that affects multiple organs. Our objective was to determine the role of ACBP in BAT function.

METHODS

Experimental models based on the targeted inactivation of the Acbp gene in brown adipocytes, both in vitro and in vivo, as well as brown adipocytes treated with recombinant ACBP, were developed and analyzed for transcriptomic and metabolic changes.

RESULTS

ACBP expression and release in BAT are suppressed by noradrenergic cAMP-dependent signals that stimulate thermogenesis. This regulation occurs through gene expression modulation and autophagy-related processes. Mice with targeted ablation of Acbp in brown adipocytes exhibit enhanced BAT thermogenic activity and protection against high-fat diet-induced obesity and glucose intolerance; this is associated with BAT transcriptome changes, including upregulation of BAT thermogenesis-related genes. Treatment of brown adipocytes with exogenous ACBP suppresses oxidative activity, lipolysis, and thermogenesis-related gene expression. ACBP treatment inhibits the noradrenergic-induced phosphorylation of p38 MAP-kinase and CREB, which are major intracellular mediators of brown adipocyte thermogenesis.

CONCLUSIONS

The ACBP system acts as a crucial auto regulatory repressor of BAT thermogenesis that responds reciprocally to the noradrenergic induction of BAT activity.

Transcriptomic profiling revealed the regulatory pathways and key genes associated with cold tolerance in two eel gobies

Closely related species of the eel goby family (Gobiidae) have evolved divergent resistance to low temperatures, but the molecular mechanisms remain poorly understood. This study used a comparative transcriptomic approach to identify key pathways and genes associated with cold tolerance in two eel goby species. Expression profiles of the cold-tolerant O. lacepedii and the cold-sensitive O. rebecca in control (23 °C) and cold stress groups (15 °C and 11 °C) were analyzed. Differentially expressed genes closely linked to interspecific cold tolerance divergence were identified through transcriptome profiling and Venn diagram analysis. GO and KEGG enrichment analyses revealed that processes related to cellular homeostasis, the PPAR signaling pathway, cellular respiration, and oxidative phosphorylation were activated during the cold tolerance response of eel gobies. WGCNA analysis indicated that the hub genes related to thermogenesis and microtubular stability, specifically PPARGC1A and α-tubulin, may contribute to the high cold tolerance in O. lacepedii. These findings provide key clues for dissection of the molecular mechanisms behind the formation of cold tolerance in eel gobies.

YTHDC1 promotes postnatal brown adipose tissue development and thermogenesis by stabilizing PPARγ

Brown adipose tissue (BAT) plays a vital role in non-shivering thermogenesis and energy metabolism and is influenced by factors like environmental temperature, ageing, and obesity. However, the molecular mechanisms behind BAT development and thermogenesis are not fully understood. Our study identifies the m6A reader protein YTHDC1 as a crucial regulator of postnatal interscapular BAT development and energy metabolism in mice. YTHDC1 directly interacts with PPARγ through its intrinsically disordered region (IDR), thus protecting PPARγ from binding the E3 ubiquitin ligase ARIH2, and preventing its ubiquitin-mediated proteasomal degradation. Specifically, the ARIH2 RING2 domain is essential for PPARγ degradation, while PPARγ's A/B domain is necessary for their interaction. Deletion of Ythdc1 in BAT increases PPARγ degradation, impairing interscapular BAT development, thermogenesis, and overall energy expenditure. These findings reveal a novel mechanism by which YTHDC1 regulates BAT development and energy homeostasis independently of its m6A recognition function.

Role of Diabetes and its metabolic pathways in Epilepsy: An insight to various target approaches

The human brain acts as a crucial organ that requires a high glucose metabolic content. However, abnormal glucose levels act as a major factor for frequent epileptic foci. Thus, it has come to attention in the recent past that epilepsy is a metabolic problem in addition to a neurological condition. However, several studies have postulated a link between epilepsy and diabetes mellitus, but very few have emphasized the exact molecular mechanism behind it and its related specific targets. Hence, this article mainly outlines in-depth knowledge about the molecular mechanisms involved and its associated target approaches. Data from several publications, such as meta-analysis, systematic and narrative reviews, and research papers obtained from electronic databases, have been used for postulating a strong evidence in order to establish a comprehensive article addressing this problem in depth. The data discussed here have revealed how adiponectin levels and mitochondrial activity impact obesity, type 2 diabetes mellitus (T2DM), and epilepsy. We have also tried to give a brief idea about the possible theories that would also impact the severity of these two conditions, including adequate exercise and the impact of commonly used AEDs. Furthermore, one of the factors causing genetic predisposition to seizures due to glucose metabolism, such as GLUT-1 deficiency, has also been described briefly. It has to be mentioned that researchers and clinical practitioners might need to take these factors into account while discovering and evaluating a suitable novel therapeutic in the future.

Are breast milk and serum irisin levels affected by the BMI and nutritional status? A prospective observational study

The influence of maternal nutritional status and anthropometric measurements on breast milk and serum irisin levels remains unclear. This study is the first to explore this relationship. This study aims to investigate the association between maternal BMI and nutritional status in the first month postpartum and their impact on breast milk and serum irisin levels. Forty-five mothers and their infants participated. Anthropometric measurements were taken at one month postpartum, maternal dietary intake was recorded over three days, and breast milk and serum irisin levels were analyzed. Overweight and obese mothers had lower breast milk irisin levels but higher serum irisin levels. A positive correlation was observed between breast milk irisin levels and infant birth weight. Additionally, serum irisin levels were positively associated with infant weight and height at one month. Maternal fiber intake was positively correlated with breast milk irisin levels, whereas fat intake showed a negative correlation. Moreover, higher folate, B12, and zinc intake were linked to increased breast milk and serum irisin levels.

CONCLUSION

Maternal BMI and nutritional status significantly influence breast milk and serum irisin levels. Promoting healthy eating habits and maintaining an optimal body weight before and after pregnancy may enhance irisin levels, potentially supporting infant growth and metabolic health.

WHAT IS KNOWN

• Irisin is a myokine involved in energy metabolism and insulin sensitivity, and breast milk composition is influenced by maternal BMI and nutritional status. • The effect of maternal obesity on breast milk irisin levels remains insufficiently understood.

WHAT IS NEW

• This is the first study to evaluate the association between maternal BMI, nutritional status, and both breast milk and serum irisin levels. • Overweight and obese mothers exhibit lower breast milk irisin but higher serum irisin levels, and maternal intake of fiber, fat, folate, vitamin B12, and zinc is significantly associated with irisin levels.

Mitonuclear Communication in Stem Cell Function

Mitochondria perform multiple functions within the cell, including the production of ATP and a great deal of metabolic intermediates, while also contributing to the cellular stress response. The majority of mitochondrial proteins are encoded by nuclear genomes, highlighting the importance of mitonuclear communication for sustaining mitochondrial homeostasis and functional. As a crucial part of the intracellular signalling network, mitochondria can impact stem cell fate determinations. Considering the essential function of stem cells in tissue maintenance, regeneration and aging, it is important to understand how mitochondria influence stem cell fate. This review explores the significant roles of mitonuclear communication and mitochondrial proteostasis, highlighting their influence on stem cells. We also examine how mitonuclear interactions contribute to cellular homeostasis, stem cell therapies, and the potential for extending lifespan.

Adaptations in mitochondrial quality control and interactions with innate immune signaling within skeletal muscle: A narrative review

Skeletal muscle health and function are essential determinants of metabolic health, physical performance, and overall quality of life. The quality of skeletal muscle is heavily dependent on the complex mitochondrial reticulum that contributes toward its unique adaptability. It is now recognized that mitochondrial perturbations can activate various innate immune pathways, such as the nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) inflammasome complex by propagating inflammatory signaling in response to damage-associated molecular patterns (DAMPs). The NLRP3 inflammasome is a multimeric protein complex and is a prominent regulator of innate immunity and cell death by mediating the activation of caspase-1, pro-inflammatory cytokines interleukin-1β and interleukin-18 and pro-pyroptotic protein gasdermin-D. While several studies have begun to demonstrate the relationship between various mitochondrial DAMPs (mtDAMPs) and NLRP3 inflammasome activation, the influence of various metabolic states on the production of these DAMPs and subsequent inflammatory profile remains poorly understood. This narrative review aimed to address this by highlighting the effects of skeletal muscle use and disuse on mitochondrial quality mechanisms including mitochondrial biogenesis, fusion, fission and mitophagy. Secondly, this review summarized the impact of alterations in mitochondrial quality control mechanisms following muscle denervation, aging, and exercise training in relation to NLRP3 inflammasome activation. By consolidating the current body of literature, this work aimed to further the understanding of innate immune signaling within skeletal muscle, which can highlight areas for future research and therapeutic strategies to regulate NLRP3 inflammasome activation during divergent metabolic conditions.

Role of T3 in the Regulation of GRP78 on Granulosa Cells in Rat Ovaries

Thyroid hormone (TH) plays a vital role in ovarian follicle development, and glucose-regulated protein 78 (GRP78) is involved in these processes, which is regulated by TH. However, the mechanisms are still unclear. To evaluate the possible mechanism of TH on the regulation of GRP78 expression, Cleavage Under Targets and Tagmentation (CUT & Tag) sequencing, luciferase assays, and Electrophoretic Mobility Shift Assays (EMSA) were employed to delineate the binding sites of thyroid hormone receptor β (TRβ) on the GRP78 promoter and to confirm the interactions. Additionally, Co-Immunoprecipitation (Co-IP) and Immunofluorescence (IF) assays were used to investigate the interactions between TRβ and the coactivator peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) after triiodothyronine (T3) treatment with different concentrations. Our findings identified a thyroid hormone response element (TRE) on the GRP78 promoter and demonstrated that TRβ can activate GRP78 expression by interacting with PGC-1α. In order to simulate the condition of hyperthyroidism, granulosa cells (GCs) extracted from rats were treated by T3 with high concentrations, which decreased the expression of PGC-1α, resulting in decreased expressions of GRP78 and other ferroptosis-related markers such as glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11, xCT), thereby inducing ferroptosis in GCs. Taken together, the present study demonstrates that T3 induces cellular ferroptosis by binding TRE of the GRP78 promoter in ovarian GCs via TRβ. As a switcher, PGC-1α is also involved in these processes.

Huddling behavior regulate adaptive thermogenesis in Brandt's voles (Lasiopodomys brandtii)

BACKGROUND

Brown adipose tissue (BAT) is the main site of non-shivering thermogenesis (NST) in small mammals, playing an important role in maintaining body temperature and energy balance. Huddling is a behavioral strategy for small rodents to save energy and improve the survival under cold environments. However, the way of huddling behavior influence on hypothalamus, which regulate BAT thermogenesis in small mammals is rarely illustrated. We used male Brandt's voles (Lasiopodomys brandtii) to explore the possible regulation mechanisms in BAT thermogenesis by the way of cold acclimation and huddling behavior.

RESULTS

There is a strong relationship between huddling behavior and NST in BAT. The hypothalamus, which is impacted by huddling behavior, influences PPAR signaling pathway in the BAT, and induces thermogenesis through Calcium signaling pathway. PPAR pathway causes crosstalk among NF-κB signaling pathway, Thermogenesis and Fatty acid metabolism to perform functions for thermogenesis.

CONCLUSIONS

The results suggest that huddling behavior can modulate adaptive thermogenesis in BAT. Cold acclimation and huddling had a synergistic effect on the regulation of thermogenic function, the hypothalamus mediates thermogenic changes in BAT induced by huddling behavior. In BAT, the specific pathway of thermogenesis is as follows: TRAF6-PPARγ-UCP1-SUCLG1.

Bone Modelling and Remodelling in Cold Environment

People engaged in various activities in cold environments-such as those living in cold climates, polar workers, cold storage workers, and athletes engaged in winter sports-are frequently affected by cold environments. Therefore, it is of great significance to explore the modelling and remodelling of bones in cold environments. Cold environments can shorten the length of bones, thin the thickness of bones, decrease bone mineral density (BMD), change the biomechanical properties of bones, and lead to bone loss. In addition, cold directly affects the bone microenvironment. Exposure to cold causes spindle-like and fibroblast-like changes in bone marrow mesenchymal stem cells (BMSCs) and decreases their proliferation, and cold exposure promotes the osteogenic differentiation of BMSCs partly through the p38 MAPK pathway. Cold also alters the dendritic differentiation of OBs by reducing the transmembrane glycoprotein E11/podoplanin and damages endothelial cells (ECs) by elevating levels of VEGF, resulting in a reduced blood supply and thus fewer OBs. In addition, cold promotes lipolysis of marrow adipose tissue (MAT), but in combination with exercise, it can promote the differentiation of BMSCs into MAT. Cold environments interfere with angiogenesis and inhibit bone growth by affecting factors such as platelet-derived growth factor type BB (PDGF-BB), slit guidance ligand 3 (SLIT3), Notch, and VEGF. In addition, cold environments may promote bone resorption by activating sympathetic nerves to activate β-adrenergic receptors and regulating leptin secretion, and regulate bone metabolism by activating the p38 MAPK signalling pathway and increasing the synthesis of brown fat, which ultimately inhibit bone formation and enhance bone resorption. In this paper, we describe the effects of cold environments on bones in the locomotor system in terms of bone structure, bone mass, biomechanical properties, and various skeletal cells, bone blood vessels, and bone fat systems in the bone microenvironment.

Atf3 controls transitioning in female mitochondrial cardiomyopathy as identified by spatial and single-cell transcriptomics

Oxidative phosphorylation defects result in now intractable mitochondrial diseases (MD) with cardiac involvement markedly affecting prognosis. The mechanisms underlying the transition from compensation to dysfunction in response to metabolic deficiency remain unclear. Here, we used spatially resolved transcriptomics and single-nucleus RNA sequencing (snRNA-seq) on the heart of a patient with mitochondrial cardiomyopathy (MCM), combined with an MCM mouse model with cardiac-specific Ndufs6 knockdown (FS6KD). Cardiomyocytes demonstrated the most heterogeneous expression landscape among cell types caused by metabolic perturbation, and pseudotime trajectory analysis revealed dynamic cellular states transitioning from compensation to severe compromise. This progression coincided with the transient up-regulation of a transcription factor, ATF3. Genetic ablation of Atf3 in FS6KD corroborated its pivotal role, effectively delaying cardiomyopathy progression in a female-specific manner. Our findings highlight a fate-determining role of ATF3 in female MCM progression and that the latest transcriptomic analysis will help decipher the mechanisms underlying MD progression.

Antioxidant and Anti-Inflammatory Defenses in Huntington's Disease: Roles of NRF2 and PGC-1α, and Therapeutic Strategies

Huntington's disease (HD) is a detrimental neurodegenerative disease caused by the expansion of a CAG triplet in the HTT gene. This mutation leads to the production of mutant Huntingtin (Htt) protein with toxic gain-of-function. The mHtt is responsible in several ways for the establishment of an intricate pathogenetic scenario in affected cells, particularly in HD neurons. Among the features of HD, oxidative stress plays a relevant role in the progression of the disease at the cellular level. Mitochondrial dysfunction, bioenergetic deficits, Reactive Oxygen Species (ROS) production, neuroinflammation, and general reduction of antioxidant levels are all involved in the promotion of a toxic oxidative environment, eventually causing cell death. Nonetheless, neuronal cells exert antioxidant molecules to build up defense mechanisms. Key components of these defensive mechanisms are the nuclear factor erythroid 2-related factor 2 (NRF2) and peroxisome proliferator-activated receptor gamma coactivator-1 α (PGC-1α). Thus, this review aims to describe the involvement of oxidative stress in HD by exploring the roles of NRF2 and PGC-1α, crucial actors in this play. Finally, antioxidant therapeutic strategies targeting such markers are discussed.

Thermogenesis and Energy Metabolism in Brown Adipose Tissue in Animals Experiencing Cold Stress

Cold exposure is a regulatory biological functions in animals. The interaction of thermogenesis and energy metabolism in brown adipose tissue (BAT) is important for metabolic regulation in cold stress. Brown adipocytes (BAs) produce uncoupling protein 1 (UCP1) in mitochondria, activating non-shivering thermogenesis (NST) by uncoupling fuel combustion from ATP production in response to cold stimuli. To elucidate the mechanisms underlying thermogenesis and energy metabolism in BAT under cold stress, we explored how cold exposure triggers the activation of BAT thermogenesis and regulates overall energy metabolism. First, we briefly outline the precursor composition and function of BA. Second, we explore the roles of the cAMP- protein kinase A (PKA) and adenosine monophosphate-activated protein kinase (AMPK) signaling pathways in thermogenesis and energy metabolism in BA during cold stress. Then, we analyze the mechanism by which BA regulates mitochondria homeostasis and energy balance during cold stress. This research reveals potential therapeutic targets, such as PKA, AMPK, UCP1 and PGC-1α, which can be used to develop innovative strategies for treating metabolic diseases. Furthermore, it provides theoretical support for optimizing cold stress response strategies, including the pharmacological activation of BAT and the genetic modulation of thermogenic pathways, to improve energy homeostasis in livestock.

5G Radiofrequency Exposure Reduces PRDM16 and C/EBP β mRNA Expression, Two Key Biomarkers for Brown Adipogenesis

The widespread use of wireless technologies has raised public health concerns about the biological effects of radiofrequency (RF) exposure. Children have a higher specific absorption rate (SAR) of radiation energy compared to adults. Furthermore, brown adipose tissue (BAT) is more prevalent in infants and tends to decrease with age. Previous animal studies demonstrated a cold sensation in rats exposed to 900 MHz (second generation, 2G). UCP1-dependent thermogenesis and BAT hyperplasia are two fundamental adaptive mechanisms initiated in response to cold. This study investigated the impact of short-term exposure to 2G and fifth generation (5G) on key thermogenic and adipogenic markers related to these mechanisms while considering age and exposure duration. Juvenile and young adult Wistar rats were randomized into three subgroups: a 5G group (3.5 GHz), 2G group (900 MHz), and a control group (SHAM). They were exposed to their respective continuous-wave RF signals for 1 or 2 weeks at an intensity of 1.5 V/m, with two exposure sessions of 1 h per day. After the exposure period, a RT-qPCR was carried out to evaluate the genetic markers involved in BAT thermogenesis and adipogenesis. Two adipogenic biomarkers were affected; a fold change reduction of 49% and 32% was detected for PRDM16 (p = 0.016) and C/EBP β (p = 0.0002), respectively, after 5G exposure, regardless of age and exposure duration. No significant RF effect was found on UCP1-dependent thermogenesis at a transcriptional level. These findings suggest that exposure to a 5G radiofrequency may partially disrupt brown adipocyte differentiation and thermogenic function by downregulating PRDM16 and C/EBP β, possibly leading to higher cold sensitivity.

Vertebrates show coordinated elevated expression of mitochondrial and nuclear genes after birth

Interactions between mitochondrial and nuclear factors are essential to life. Nevertheless, the importance of coordinated regulation of mitochondrial-nuclear gene expression (CMNGE) to changing physiological conditions is poorly understood and is limited to certain tissues and organisms. We hypothesized that CMNGE is important for development across vertebrates and, hence, should be conserved. As a first step, we analyzed more than 1400 RNA-seq experiments performed during prenatal development, in neonates, and in adults across vertebrate evolution. We find conserved sharp elevation of CMNGE after birth, including oxidative phosphorylation (OXPHOS) and mitochondrial ribosome genes, in the heart, hindbrain, forebrain, and kidney across mammals, as well as in Gallus gallus and in the lizard Anolis carolinensis This is accompanied by elevated expression of TCA cycle enzymes and reduction in hypoxia response genes, suggesting a conserved cross-tissue metabolic switch after birth/hatching. Analysis of about 70 known regulators of mitochondrial gene expression reveals consistently elevated expression of PPARGC1A (also known as Pgc-1alpha) and CEBPB after birth/hatching across organisms and tissues, thus highlighting them as candidate regulators of CMNGE upon transition to the neonate. Analyses of Danio rerio, Xenopus tropicalis, Caenorhabditis elegans, and Drosophila melanogaster reveal elevated CMNGE prior to hatching in X. tropicalis and in D. melanogaster, which is associated with the emergence of muscle activity. Lack of such an ancient pattern in mammals and in chickens suggests that it was lost during radiation of terrestrial vertebrates. Taken together, our results suggest that regulated CMNGE after birth reflects an essential metabolic switch that is under strong selective constraints.

Transcriptional dynamics in type 2 diabetes progression is linked with circadian, thermogenic, and cellular stress in human adipose tissue

The prevalence of type 2 diabetes (T2D) has increased significantly over the past three decades, with an estimated 30-40% of cases remaining undiagnosed. Brown and beige adipose tissues are known for their remarkable catabolic capacity, and their ability to diminish blood glucose plasma concentration. Beige adipose tissue can be differentiated from adipose-derived stem cells or through transdifferentiation from white adipocytes. However, the impact of T2D progression on beige adipocytes' functional capacity remains unclear. Transcriptomic profiling of subcutaneous adipose tissue biopsies from healthy normal-weight, obese, prediabetic obese, and obese subjects diagnosed with T2D, reveals a progressive alteration in cellular processes associated with catabolic metabolism, circadian rhythms, thermogenesis-related signaling pathways, cellular stress, and inflammation. MAX is a potential transcription factor that links inflammation with the circadian clock and thermogenesis during the progression of T2D. This study unveils an unrecognized transcriptional circuit that increasingly disrupts subcutaneous adipose tissue oxidative capacity during the progression of T2D. These findings could open new research venues for developing chrono-pharmaceutical strategies to treat and prevent T2D.

Role of trans-resveratrol in ameliorating biochemical and molecular alterations in obese rats induced by a high fructose/fat diet

We evaluated the effect of trans-resveratrol (RSV) in ameliorating biochemical and molecular alterations in obese Wister male rats fed on high-fat/high-fructose-fed. Male Wister rats were divided into eight groups and fed with either a standard diet (control), high fructose (HF), high fat (HFAT), or a high- fructose high- fat (HF/HFAT) diet and supplemented with RSV (30 mg/kg/day) for 4 weeks. The food intake, body weight, glycemic parameters, lipid profile, oxidative stress were assessed. SIRT1 gene expression, PGC-1α, cyto-c and GLUT-4 were evaluated by qRT-PCR in adipose tissue of normal and obese rats. The body weight gain, serum fasting glucose, insulin, and HOMA-IR values were significantly higher in the HF and HF/HFAT groups than in the HFAT and control groups. Hyperlipidemia was observed in high calorie diets fed rats compared to control group. The levels of total cholesterol, triglycerides and LDL-c were significantly elevated while HDL- c was significantly decreased in HF & HF/HFAT groups compared to HFAT group. The levels of serum malondialdhyde (MDA) and superoxide dismutase (SOD) activity in adipose tissue were elevated in all groups compared to control group, particularly in the groups that were kept on a high fructose diets (HF, HF/HFAT). SIRT-1, PGC-1α, Cyto-c, and GLUT-4 genes levels were significantly down regulated in HF, HFAT & HF/HFAT groups compared to control group. Supplementation of T-RSV restored the alteration in carbohydrates-lipid metabolism as well as oxidative stress and upregulation of SIRT-1, PGC-1α, Cyto-c, and GLUT-4 genes. RSV is a promising treatment in the management of pathologic consequences of obesity from high-calorie diet consumption via molecular alteration of target genes.

RBM43 controls PGC1α translation and a PGC1α-STING signaling axis

Obesity is associated with systemic inflammation that impairs mitochondrial function. This disruption curtails oxidative metabolism, limiting adipocyte lipid metabolism and thermogenesis, a metabolically beneficial program that dissipates chemical energy as heat. Here, we show that PGC1α, a key governor of mitochondrial biogenesis, is negatively regulated at the level of its mRNA translation by the RNA-binding protein RBM43. RBM43 is induced by inflammatory cytokines and suppresses mitochondrial biogenesis in a PGC1α-dependent manner. In mice, adipocyte-selective Rbm43 disruption elevates PGC1α translation and oxidative metabolism. In obesity, Rbm43 loss improves glucose tolerance, reduces adipose inflammation, and suppresses activation of the innate immune sensor cGAS-STING in adipocytes. We further identify a role for PGC1α in safeguarding against cytoplasmic accumulation of mitochondrial DNA, a cGAS ligand. The action of RBM43 defines a translational regulatory axis by which inflammatory signals dictate cellular energy metabolism and contribute to metabolic disease pathogenesis.

Unraveling the Health Benefits and Mechanisms of Time-Restricted Feeding: Beyond Caloric Restriction

Time-restricted feeding (TRF) is a lifestyle intervention that aims to maintain a consistent daily cycle of feeding and fasting to support robust circadian rhythms. Recently, it has gained scientific, medical, and public attention due to its potential to enhance body composition, extend lifespan, and improve overall health, as well as induce autophagy and alleviate symptoms of diseases like cardiovascular diseases, type 2 diabetes, neurodegenerative diseases, cancer, and ischemic injury. However, there is still considerable debate on the primary factors that contribute to the health benefits of TRF. Despite not imposing strict limitations on calorie intake, TRF consistently led to reductions in calorie intake. Therefore, while some studies suggest that the health benefits of TRF are primarily due to caloric restriction (CR), others argue that the key advantages of TRF arise not only from CR but also from factors like the duration of fasting, the timing of the feeding period, and alignment with circadian rhythms. To elucidate the roles and mechanisms of TRF beyond CR, this review incorporates TRF studies that did not use CR, as well as TRF studies with equivalent energy intake to CR, which addresses the previous lack of comprehensive research on TRF without CR and provides a framework for future research directions.

NRF-1 promotes FUNDC1-mediated mitophagy as a protective mechanism against hypoxia-induced injury in cardiomyocytes

Hypoxia-induced apoptosis and mitochondrial dysfunction in cardiomyocytes are involved in the mechanisms of heart failure. Our previous studies have confirmed that NRF-1 alleviates hypoxia-induced injury by promoting mitochondrial function and inhibiting apoptosis in cardiomyocytes. However, the mechanism by which NRF-1 attenuates hypoxia-induced injury in cardiomyocytes is still unclear. Mitophagy, a selective autophagy, has recently shown a remarkable correlation with hypoxia-induced cardiomyocyte injury. In this study, we evaluated whether NRF-1 protects cardiomyocytes from hypoxia-induced injury by regulating mitophagy. The findings indicate that hypoxia prevents H9c2 cells from growing, encourages mitochondrial dysfunction, and triggers mitophagy. In addition, promoting mitophagy by rapamycin reduces hypoxia-induced injury in H9c2 cells. Overexpression of NRF-1 in hypoxia-induced H9c2 cells promotes mitophagy and alleviates cell injury, and this effect can be inhibited by 3-MA. Further study found that NRF-1 promotes the expression of FUNDC1 by binding to its promoter region. Knockdown of FUNDC1 in NRF-1 over-expression H9c2 cells inhibited mitophagy and aggravated hypoxia-induced injury. In conclusion, our study suggests that NRF-1 protects against hypoxia-induced injury by regulating FUNDC1-mediated mitophagy in cardiomyocytes.

mTORC1 and 2 Adrenergic Regulation and Function in Brown Adipose Tissue

Brown adipose tissue (BAT) thermogenesis results from the uncoupling of mitochondrial inner membrane proton gradient mediated by uncoupling protein 1 (UCP-1), which is activated by lipolysis-derived fatty acids. Norepinephrine (NE) secreted by sympathetic innervation not only activates BAT lipolysis and UCP-1 but, uniquely in brown adipocytes, promotes "futile" metabolic cycles and enhances BAT thermogenic capacity by increasing UCP-1 content, mitochondrial biogenesis, and brown adipocyte hyperplasia. NE exerts these actions by triggering signaling in the canonical G protein-coupled β-adrenergic receptors, cAMP, and protein kinase A (PKA) pathway, which in brown adipocytes is under a complex and intricate cross talk with important growth-promoting signaling pathways such as those of mechanistic target of rapamycin (mTOR) complexes 1 (mTORC1) and 2 (mTORC2). This article reviews evidence suggesting that mTOR complexes are modulated by and participate in the thermogenic, metabolic, and growth-promoting effects elicited by NE in BAT and discusses current gaps and future directions in this field of research.

Expression of PGC-1α, PPAR-α and UCP1 genes, metabolic and anthropometric factors in response to sodium butyrate supplementation in patients with obesity: a triple-blind, randomized placebo-controlled clinical trial

OBJECTIVES

There is increasing evidence that gut metabolites have a role in the etiology of obesity. This study aimed to investigate the effects of sodium butyrate (NaB) supplementation on the expression of peroxisome proliferator-activated receptor (PPAR) gamma coactivator-1α (PGC-1α), PPAR-α, and uncoupling protein-1 (UCP-1) genes, as well as on the metabolic parameters and anthropometric indices in persons with obesity.

METHODS

In this triple-blind placebo-controlled randomized clinical trial, 50 individuals with obesity were randomly assigned to NaB (600 mg/day) + hypo-caloric diet or placebo group + hypo-caloric diet for 8 weeks. The study measured the participants' anthropometric characteristics, food consumption, and feelings of hunger in addition to the serum levels of metabolic indices and the mRNA expression of the PGC-1α, PPAR-α, and UCP-1 genes in peripheral blood mononuclear cells (PBMCs).

RESULTS

PGC-1α and UCP-1 genes expression significantly increased in NaB group compared to the placebo at the endpoint. A significant decrease in weight, BMI, and waist circumference (WC) was observed in NaB group. Among the metabolic factors, NaB significantly decreased fasting blood sugar (FBS) (P = 0.04), low-density lipoprotein cholesterol (LDL-C) (P = 0.038) and increased high-density lipoprotein cholesterol (HDL-C) (P = 0.016). NaB could not significantly change serum GLP-1 level.

CONCLUSIONS

This study unveiled NaB supplementation alone cannot have significant beneficial effects on anthropometric, and biochemical factors. NaB could affect anthropometric and metabolic risk variables associated with obesity only when prescribed, along with calorie restriction.

CLINICAL TRIAL REGISTRATION

This study was registered in the Iranian Registry of Clinical Trials ( https://en.irct.ir/trial/53968 ) on 31 January 2021 (registry number IRCT20190303042905N2).

Evolution of UCP1 Gene and Its Significance to Temperature Adaptation in Rodents

Adaptive thermogenesis comprises shivering thermogenesis dependent on skeletal muscles and non-shivering thermogenesis (NST) mediated by uncoupling protein 1 (UCP1). Although the thermogenic function of UCP1 was adopted early in some placental mammals, positive selection predominantly occurred in the ancestral branches of small-bodied species. Some previous studies have revealed that rodents living in northern or high mountain regions adapt to cold environments by increasing NST, whereas those living in tropical and subtropical regions that are not exposed to cold stress express low concentrations of UCP1, indicating that UCP1 may have evolved to adapt to ambient temperatures. In this study, we explored the evolution of UCP1 and its significance to temperature adaptation by performing detailed evolutionary and statistical analyses on 64 rodents with known genomes. As a result, a total of 71 UCP1 gene sequences were obtained, including 47 intact genes, 22 partial genes, and 2 pseudogenes. Further, 47 intact genes and 3 previously published intact UCP1 genes were incorporated into evolutionary analyses, and correlation analyses between evolutionary rate and ambient temperatures (including average annual temperature, maximum temperature, and minimum temperature) of the rodent survives were conducted. The results show that UCP1 is under purifying selection (ω = 0.11), and among rodents with intact UCP1 sequences, Urocitellus parryii and Dicrostonyx groenlandicus-the two species with the lowest ambient temperatures among the rodents used here-have higher evolutionary rates than others. In the statistical analyses, in addition to ambient temperatures, body weight and weight at birth were also taken into account since weight was previously proposed to be linked to UCP1 evolution. The results showed that after controlling for the phylogenetic effect, the maximum temperature was significantly negatively correlated with the evolutionary rate of UCP1, whereas weight did not have a relationship with UCP1 evolutionary rate. Consequently, it is suggested that ambient temperature can drive the evolution of rodent UCP1, thereby enhancing NST adaptation to cold stress.

Exploratory Review and In Silico Insights into circRNA and RNA-Binding Protein Roles in γ-Globin to β-Globin Switching

β-globin gene cluster regulation involves complex mechanisms to ensure proper expression and function in RBCs. During development, switching occurs as γ-globin is replaced by β-globin. Key regulators, like BCL11A and ZBTB7A, repress γ-globin expression to facilitate this transition with other factors, like KLF1, LSD1, and PGC-1α; these regulators ensure an orchestrated transition from γ- to β-globin during development. While these mechanisms have been extensively studied, circRNAs have recently emerged as key contributors to gene regulation, but their role in β-globin gene cluster regulation remains largely unexplored. Although discovered in the 1970s, circRNAs have only recently been recognized for their functional roles, particularly in interactions with RNA-binding proteins. Understanding how circRNAs contribute to switching from γ- to β-globin could lead to new therapeutic strategies for hemoglobinopathies, such as sickle cell disease and β-thalassemia. This review uses the circAtlas 3.0 database to explore circRNA expressions in genes related to switching from γ- to β-globin expression, focusing on blood, bone marrow, liver, and spleen. It emphasizes the exploration of the potential interactions between circRNAs and RNA-binding proteins involved in β-globin gene cluster regulatory mechanisms, further enhancing our understanding of β-globin gene cluster expression.

The role of mitochondrial biogenesis, mitochondrial dynamics and mitophagy in gastrointestinal tumors

Gastrointestinal tumors remain the leading causes of cancer-related deaths, and their morbidity and mortality remain high, which imposes a great socio-economic burden globally. Mitochondrial homeostasis depend on proper function and interaction of mitochondrial biogenesis, mitochondrial dynamics (fission and fusion) and mitophagy. Recent studies have demonstrated close implication of mitochondrial homeostasis in gastrointestinal tumorigenesis and development. In this review, we summarized the research progress on gastrointestinal tumors and mitochondrial quality control, as well as the underlying molecular mechanisms. It is anticipated that the comprehensive understanding of mitochondrial homeostasis in gastrointestinal carcinogenesis would benefit the application of mitochondria-targeted therapies for gastrointestinal tumors in future.

G-Protein-Coupled Receptor (GPCR) Signaling and Pharmacology in Metabolism: Physiology, Mechanisms, and Therapeutic Potential

G-protein coupled receptors (GPCRs), the largest family of integral membrane proteins, enable cells to sense and appropriately respond to the environment through mediating extracellular signaling to intercellular messenger molecules. GPCRs' pairing with a diverse array of G protein subunits and related downstream secondary messengers, combined with their ligand versatility-from conventional peptide hormone to numerous bioactive metabolites, allow GPCRs to comprehensively regulate metabolism and physiology. Consequently, GPCRs have garnered significant attention for their therapeutic potential in metabolic diseases. This review focuses on six GPCRs, GPR40, GPR120, GLP-1R, and ß-adrenergic receptors (ADRB1, ADRB2, and ADRB3), with GLP-1R recognized as a prominent regulator of system-level metabolism, while the roles of GPR40, GPR120 and ß-adrenergic receptors in central carbon metabolism and energy homeostasis are increasingly appreciated. Here, we discuss their physiological functions in metabolism, the current pharmacological landscape, and the intricacies of their signaling pathways via G protein and ß-arrestin activation. Additionally, we discuss the limitations of existing GPCR-targeted strategies for treating metabolic diseases and offer insights into future perspectives for advancing GPCR pharmacology.

Eugenol Promotes Apoptosis in Leukemia Cells via Targeting the Mitochondrial Biogenesis PPRC1 Gene

Acute myeloid leukemia (AML) is a highly heterogenous and aggressive myeloid neoplasm. To sustain growth and survival, AML cells, like other neoplasms, require energy. This process is orchestrated by mitochondria and is under the control of several genes, such as PPRC1 (PRC), a member of the PGC-1 family, which is a key player in the transcription control of mitochondrial biogenesis. We have shown here that eugenol inhibits cell growth and promotes apoptosis through the mitochondrial pathway in AML cell lines as well as in cells from AML patients but not in cells from healthy donors. Similar effects were also observed on cytarabine-resistant AML cells. Interestingly, eugenol downregulated PPRC1 at both the protein and mRNA levels and reduced mitochondrial membrane potential in AML cells. We have also shown that PPRC1 expression is higher in cancer cells from blood, breast, and other types of cancer relative to normal cells, and high PPRC1 levels correlate significantly with short overall survival (OS). In addition, PPRC1 gene mutations significantly correlate with short OS and/or disease-free survival in several cancers. PPRC1 mutations also correlated significantly with poor OS (p < 0.0001) when tested in a total of 23,456 cancer patients. These findings suggest an oncogenic role of PPRC1 in various types of cancer and the possible eugenol-targeting of this gene for the treatment of AML patients, especially those exhibiting resistance to cytarabine.

Environmental Enrichment Normalizes Metabolic Function in the Murine Model of Prader-Willi Syndrome Magel2-Null Mice

Prader-Willi syndrome (PWS) is a rare genetic disease that causes developmental delays, intellectual impairment, constant hunger, obesity, endocrine dysfunction, and various behavioral and neuropsychiatric abnormalities. Standard care of PWS is limited to strict supervision of food intake and GH therapy, highlighting the unmet need for new therapeutic strategies. Environmental enrichment (EE), a housing environment providing physical, social, and cognitive stimulations, exerts broad benefits on mental and physical health. Here we assessed the metabolic and behavioral effects of EE in the Magel2-null mouse model of PWS. EE initiated after the occurrence of metabolic abnormality was sufficient to normalize body weight and body composition, reverse hyperleptinemia, and improve glucose metabolism in the male Magel2-null mice. These metabolic improvements induced by EE were comparable to those achieved by a hypothalamic brain-derived neurotrophic factor gene therapy although the underlying mechanisms remain to be determined. These data suggest biobehavioral interventions such as EE could be effective in the treatment of PWS-related metabolic abnormalities.

Sulforaphane treatment mimics contractile activity-induced mitochondrial adaptations in muscle myotubes

Mitochondria are metabolic hubs that govern skeletal muscle health. Although exercise has been established as a powerful inducer of quality control processes that ultimately enhance mitochondrial function, there are currently limited pharmaceutical interventions available that emulate exercise-induced mitochondrial adaptations. To investigate a novel candidate for this role, we examined sulforaphane (SFN), a naturally occurring compound found in cruciferous vegetables. SFN has been documented as a potent antioxidant inducer through its activation of the nuclear factor erythroid 2-related factor 2 (Nrf-2) antioxidant response pathway. However, its effects on muscle health have been underexplored. To investigate the interplay between chronic exercise and SFN, C2C12 myotubes were electrically stimulated to model chronic contractile activity (CCA) in the presence or absence of SFN. SFN promoted Nrf-2 nuclear translocation, enhanced mitochondrial respiration, and upregulated key antioxidant proteins including catalase and glutathione reductase. These adaptations were accompanied by reductions in cellular and mitochondrial reactive oxygen species (ROS) emission. Signaling toward biogenesis was enhanced, demonstrated by increases in mitochondrial transcription factor A (TFAM), peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1α nuclear translocation, PGC-1α promoter activity, mitochondrial content, and organelle branching, suggestive of a larger, more interconnected mitochondrial pool. These mitochondrial adaptations were accompanied by an increase in lysosomal proteins, suggesting coordinated regulation. There was no difference in mitochondrial and antioxidant-related proteins between CCA and non-CCA SFN-treated cells. Our data suggest that SFN activates signaling cascades that are common to those produced by contractile activity, indicating that SFN-centered therapeutic strategies may improve the mitochondrial phenotype in skeletal muscle.NEW & NOTEWORTHY Nrf-2 is a transcription factor that has been implicated in mitigating oxidative stress and regulating mitochondrial homeostasis. However, limited research has demonstrated how Nrf-2-mediated adaptations compare with those produced by exercise. To investigate this, we treated myotubes with Sulforaphane, a well-established Nrf-2 activator, and combined this with stimulation-induced chronic contractile activity to model exercise training. Our work is the first to establish that sulforaphane mimics training-induced mitochondrial adaptations, including enhancements in respiration, biogenesis, and dynamics.

Role of PGC-1α in the proliferation and metastasis of malignant tumors

Malignant tumors are among the major diseases threatening human survival in the world, and advancements in medical technology have led to a steady increase in their detection rates worldwide. Despite unique clinical presentations across the spectrum of malignancies, treatment modalities generally adhere to common strategies, encompassing primarily surgical intervention, radiation therapy, chemotherapy, and targeted treatments. Uncovering the genetic elements contributing to cancer cell proliferation, metastasis, and drug resistance remains a pivotal pursuit in the development of novel targeted therapeutics. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A/PGC-1α) is a transcriptional coactivator that influences most cellular metabolic pathways. Its aberrant expression is associated with numerous chronic diseases, including diabetes, heart failure, neurodegenerative disorders, and cancer development. This study primarily discusses the structure, physiological functions, regulatory mechanisms, and research advancement concerning the role of PGC-1α in the proliferation and metastasis of malignant tumors. Targeting PGC-1α and its related regulatory pathways for therapeutic interventions holds promise in facilitating precise and individualized oncological treatments. This approach is expected to counteract drug resistance in patients with cancer and offer a novel direction for the treatment of malignant tumors.

Recent Insights on the Role of Nuclear Receptors in Alzheimer's Disease: Mechanisms and Therapeutic Application

Nuclear receptors (NRs) are ligand-activated transcription factors that regulate a broad array of biological processes, including inflammation, lipid metabolism, cell proliferation, and apoptosis. Among the diverse family of NRs, peroxisome proliferator-activated receptors (PPARs), estrogen receptor (ER), liver X receptor (LXR), farnesoid X receptor (FXR), retinoid X receptor (RXR), and aryl hydrocarbon receptor (AhR) have garnered significant attention for their roles in neurodegenerative diseases, particularly Alzheimer's disease (AD). NRs influence the pathophysiology of AD through mechanisms such as modulation of amyloid-beta (Aβ) deposition, regulation of inflammatory pathways, and improvement of neuronal function. However, the dual role of NRs in AD progression, where some receptors may exacerbate the disease while others offer therapeutic potential, presents a critical challenge for their application in AD treatment. This review explores the functional diversity of NRs, highlighting their involvement in AD-related processes and discussing the therapeutic prospects of NR-targeting strategies. Furthermore, the key challenges, including the necessity for the precise identification of beneficial NRs, detailed structural analysis through molecular dynamics simulations, and further investigation of NR mechanisms in AD, such as tau pathology and autophagy, are also discussed. Collectively, continued research is essential to clarify the role of NRs in AD, ultimately facilitating their potential use in the diagnosis, prevention, and treatment of AD.

Study on the role of Dihuang Yinzi in regulating the AMPK/SIRT1/PGC-1α pathway to promote mitochondrial biogenesis and improve Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Dihuang Yinzi (DHYZ) is a classic prescription in traditional Chinese medicine. Its therapeutic effect on Alzheimer's disease (AD) has been widely validated. However, the underlying molecular mechanisms of DHYZ in AD treatment remain unclear and require further research.

AIM OF THE STUDY

Elucidating DHYZ's promotion of mitochondrial biogenesis through the AMPK/SIRT1/PGC-1α pathway improves neuronal loss, mitochondrial damage, and memory deficits in AD.

MATERIALS AND METHODS

Administering DHYZ by gavage to SAMP8 mice, after completing behavioral tests, the effects of DHYZ on hippocampal neuron loss and mitochondrial structural damage in AD model mice were assessed using Nissl staining and transmission electron microscopy. Western blot was used to detect the expression of mitochondrial biogenesis-related proteins PGC-1α, CREB, mitochondrial fusion protein MFN2, and mitochondrial fission proteins DRP1 and FIS1. At the same time, immunofluorescence (IF) was employed to measure the relative fluorescence intensity of mitochondrial fusion protein MFN1. After determining the optimal dose of DYHZ for treating AD, we conducted mechanistic studies. By intraperitoneally injecting SAMP8 mice with the AMPK inhibitor (Compound C) to inhibit AMPK protein expression and subsequently treating them with DHYZ, the impact of DHYZ on hippocampal neurons in AD model mice was evaluated using Nissl and hematoxylin-eosin staining. Western blot was used to detect the protein expression of AMPK, p-AMPK, SIRT1, PGC-1α, NRF1, and TFAM. In contrast, IF was used to measure the relative fluorescence intensity of PGC-1α, NRF1, and TFAM proteins in the hippocampal CA1 region.

RESULTS

DHYZ significantly improved AD model mice's cognitive impairment and memory deficits and mitigated hippocampal neuron loss and degeneration. Additionally, it ameliorated mitochondrial morphological structures. DHYZ upregulated the protein expression of mitochondrial biogenesis-related proteins PGC-1α, CREB, and mitochondrial fusion proteins MFN1 and MFN2 while inhibiting the expression of mitochondrial fission proteins DRP1 and FIS1. Further studies revealed that DHYZ could upregulate the expression of the AMPK/SIRT1/PGC-1α pathway proteins and their downstream proteins NRF1 and TFAM.

CONCLUSION

DHYZ promotes mitochondrial biogenesis by activating the AMPK/SIRT1/PGC-1α signaling pathway, thereby improving memory deficits, neuronal loss, and mitochondrial dysfunction in AD.

Unraveling mitochondrial dysfunction: comprehensive perspectives on its impact on neurodegenerative diseases

Neurodegenerative diseases represent a significant challenge to modern medicine, with their complex etiology and progressive nature posing hurdles to effective treatment strategies. Among the various contributing factors, mitochondrial dysfunction has emerged as a pivotal player in the pathogenesis of several neurodegenerative disorders. This review paper provides a comprehensive overview of how mitochondrial impairment contributes to the development of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, driven by bioenergetic defects, biogenesis impairment, alterations in mitochondrial dynamics (such as fusion or fission), disruptions in calcium buffering, lipid metabolism dysregulation and mitophagy dysfunction. It also covers current therapeutic interventions targeting mitochondrial dysfunction in these diseases.

Mitochondrial Dysfunction in Congenital Heart Disease

Mitochondria play a crucial role in multiple cellular processes such as energy metabolism, generation of reactive oxygen species, excitation-contraction coupling, cell survival and death. Dysfunction of mitochondria contributes to the development of cancer; neuromuscular, cardiovascular/congenital heart disease; and metabolic diseases, including diabetes. Mitochondrial dysfunction can result in excessive reactive oxygen species, a decrease in energy production, mitophagy and apoptosis. All these processes are known to be dysregulated in cardiovascular diseases. The focus of this review is to summarize our current knowledge of mitochondrial dysfunction, including mitophagy and apoptosis, in pediatric congenital heart disease due to maternal diabetes or due to structural cardiac defects, with a focus on single-ventricle congenital heart disease. We also discuss recent mitochondria-targeted therapies for cardiovascular diseases.

Lipid metabolism and food ingredients from the perspective of thermogenic adipocytes

The high heat-producing capacity of brown and beige adipocytes, collectively known as thermogenic adipocytes, contributes to whole-body energy expenditure and is an attractive target for the management of obesity. It has been revealed that the functions of thermogenic adipocytes are important for the regulation of whole-body carbohydrate and lipid metabolism, and the activation of thermogenic adipocytes seems to have beneficial effects for the management of obesity-related metabolic disorders, such as dyslipidemia. Recent studies have showed that specific food ingredients have the potential to activate thermogenic adipocytes via various mechanisms. Some of these are effective not only in rodents, but also in humans, and effective prevention of obesity using these food ingredients is expected. In this review, we introduce the recent findings on the regulatory mechanisms of lipid metabolism by thermogenic adipocytes and food ingredients, demonstrating the potential to activate thermogenic adipocytes and their underlying mechanisms.

The Role of microRNA-22 in Metabolism

microRNA-22 (miR-22) plays a pivotal role in the regulation of metabolic processes and has emerged as a therapeutic target in metabolic disorders, including obesity, type 2 diabetes, and metabolic-associated liver diseases. While miR-22 exhibits context-dependent effects, promoting or inhibiting metabolic pathways depending on tissue and condition, current research highlights its therapeutic potential, particularly through inhibition strategies using chemically modified antisense oligonucleotides. This review examines the dual regulatory functions of miR-22 across key metabolic pathways, offering perspectives on its integration into next-generation diagnostic and therapeutic approaches while acknowledging the complexities of its roles in metabolic homeostasis.

From molecular to physiological responses: improved stress tolerance and longevity in Drosophila melanogaster under fluctuating thermal regimes

Climate change introduces greater thermal variability, profoundly affecting ectothermic species whose body temperatures rely heavily on the environment. Understanding the physiological and metabolic responses to such variability is crucial for predicting how these species will cope with changing climates. This study investigates how chronic thermal stress impacts mitochondrial metabolism and physiological parameters in Drosophila melanogaster, hypothesizing that a fluctuating thermal regime (FTR) activates protective mechanisms enhancing stress tolerance and longevity. To test this, Drosophila were exposed to constant 24°C or to an FTR of 24°C:15°C (day:night) cycle following an initial 5 day period at 24°C. The FTR group exhibited rapid transcript level changes after the first day of FTR, particularly those related to heat shock proteins, mitophagy and regulatory factors, which returned to initial levels after 5 days. Mitochondrial respiration rates initially decreased after 1 and 2 days of FTR, then recovered by day 5, indicating rapid acclimation. Enhanced antioxidant enzyme activities were observed early in the FTR group, after 1 day for mtSOD and SODcyt+ext and 3 days for both SOD and catalase, followed by a decline by day 5, suggesting efficient oxidative stress management. The FTR group showed lower CTmax on day 3, reflecting possible physiological strain at that time point, and complete recovery by day 5. Longevity increased under FTR, highlighting the activation of protective mechanisms with beneficial long-term effects. These results suggest that FTR prompts a temporal succession of rapid physiological adjustments at different levels of organisation, enhancing long-term survival in D. melanogaster.

Mitochondrial diseases: from molecular mechanisms to therapeutic advances

Mitochondria are essential for cellular function and viability, serving as central hubs of metabolism and signaling. They possess various metabolic and quality control mechanisms crucial for maintaining normal cellular activities. Mitochondrial genetic disorders can arise from a wide range of mutations in either mitochondrial or nuclear DNA, which encode mitochondrial proteins or other contents. These genetic defects can lead to a breakdown of mitochondrial function and metabolism, such as the collapse of oxidative phosphorylation, one of the mitochondria's most critical functions. Mitochondrial diseases, a common group of genetic disorders, are characterized by significant phenotypic and genetic heterogeneity. Clinical symptoms can manifest in various systems and organs throughout the body, with differing degrees and forms of severity. The complexity of the relationship between mitochondria and mitochondrial diseases results in an inadequate understanding of the genotype-phenotype correlation of these diseases, historically making diagnosis and treatment challenging and often leading to unsatisfactory clinical outcomes. However, recent advancements in research and technology have significantly improved our understanding and management of these conditions. Clinical translations of mitochondria-related therapies are actively progressing. This review focuses on the physiological mechanisms of mitochondria, the pathogenesis of mitochondrial diseases, and potential diagnostic and therapeutic applications. Additionally, this review discusses future perspectives on mitochondrial genetic diseases.

Irisin in thyroid diseases

Irisin, a hormone-like adipo-myokine, has garnered considerable attention in recent years for its potential impact in metabolic diseases. Its physiological effects are similar to those of thyroid hormones, prompting numerous investigations into potential correlations and interactions between irisin and thyroid function through various in vitro and animal experiments. However, existing studies suggest that the relationship between irisin and thyroid diseases is highly complex and multifaceted. In this paper, we have summarized the research results on serum irisin and thyroid function, providing an overview of advancements and constraints in current research on irisin and thyroid hormones. The aim is to offer insights and directions for future clinical trials in this field.

PGC-1α regulation by FBXW7 through a novel mechanism linking chaperone-mediated autophagy and the ubiquitin-proteasome system

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is a key regulator of mitochondrial biogenesis and antioxidative defenses, and it may play a critical role in Parkinson's disease (PD). F-box/WD repeat domain-containing protein (FBXW7), an E3 protein ligase, promotes the degradation of substrate proteins through the ubiquitin-proteasome system (UPS) and leads to the clearance of PGC-1α. Here, we elucidate a novel post-translational mechanism for regulating PGC-1α levels in neurons. We show that enhancing chaperone-mediated autophagy (CMA) activity promotes the CMA-mediated degradation of FBXW7 and consequently increases PGC-1α. We confirm the relevance of this pathway in vivo by showing decreased FBXW7 and increased PGC-1α as a result of boosting CMA selectively in dopaminergic (DA) neurons by overexpressing lysosomal-associated membrane protein 2A (LAMP2A) in TH-Cre-LAMP2-loxp conditional mice. We further demonstrate that these mice are protected against MPTP-induced oxidative stress and neurodegeneration. These results highlight a novel regulatory pathway for PGC-1α in DA neurons and suggest targeted increasing of CMA or decreasing FBXW7 in DA neurons as potential neuroprotective strategies in PD.

Muscle PGC-1α Overexpression Drives Metabolite Secretion Boosting Subcutaneous Adipocyte Browning

Muscle and adipose tissue (AT) are in mutual interaction through the integration of endocrine and biochemical signals, thus regulating whole-body function and physiology. Besides a traditional view of endocrine relationships that imply the release of cytokines and growth factors, it is becoming increasingly clear that a metabolic network involving metabolites as signal molecules also exists between the two tissues. By elevating the number and functionality of mitochondria, a key role in muscle metabolism is played by the master regulator of mitochondrial biogenesis peroxisome-proliferator-activated receptor-γ coactivator-1α (PGC-1α), that induces a fiber type shift from glycolytic to oxidative myofibers. As a consequence, the upregulation of muscle respiratory rate might affect metabolite production and consumption. However, the underlying mechanisms have not yet been fully elucidated. Here, we used a muscle-specific PGC-1α overexpressing mouse model (MCK-PGC-1α) to analyze the metabolite secretion profile of serum and culture medium recovered from MCK-PGC-1α muscle fibers by NMR. We revealed modified levels of different metabolites that might be ascribed to the metabolic activation of the skeletal muscle fibers. Notably, the dysregulated levels of these metabolites affected adipocyte differentiation, as well as the browning process in vitro and in vivo. Interestingly such effect was exacerbated in the subcutaneous WAT, while only barely present in the visceral WAT. Our data confirm a prominent role of PGC-1α as a trigger of mitochondrial function in skeletal muscle and propose a novel function of this master regulator gene in modulating the metabolite production in turn affecting the activation of WAT and its conversion toward the browning.

Impaired endothelial function contributes to cardiac dysfunction: role of mitochondrial dynamics

The endothelial microvasculature is essential for the regulation of vasodilation and vasoconstriction, and improved functioning of the endothelium is linked to improved outcomes for individuals with coronary artery disease (CAD). People with endothelial dysfunction exhibit a loss of nitric oxide (NO)-mediated vasodilation, achieving vasodilation instead through mitochondria-derived H2O2. Mitochondrial dynamics is an important autoregulatory mechanism that contributes to mitochondrial and endothelial homeostasis and plays a role in the formation of reactive oxygen species (ROS), including H2O2. Dysregulation of mitochondrial dynamics leads to increased ROS production, decreased ATP production, impaired metabolism, activation of pathological signal transduction, impaired calcium sensing, and inflammation. We hypothesize that dysregulation of endothelial mitochondrial dynamics plays a crucial role in the endothelial microvascular dysfunction seen in individuals with CAD. Therefore, proper regulation of endothelial mitochondrial dynamics may be a suitable treatment for individuals with endothelial microvascular dysfunction, and we furthermore postulate that improving this microvascular dysfunction will directly improve outcomes for those with CAD.

Alpha-Synuclein Effects on Mitochondrial Quality Control in Parkinson's Disease

The maintenance of healthy mitochondria is essential for neuronal survival and relies upon mitochondrial quality control pathways involved in mitochondrial biogenesis, mitochondrial dynamics, and mitochondrial autophagy (mitophagy). Mitochondrial dysfunction is critically implicated in Parkinson's disease (PD), a brain disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra. Consequently, impaired mitochondrial quality control may play a key role in PD pathology. This is affirmed by work indicating that genes such as PRKN and PINK1, which participate in multiple mitochondrial processes, harbor PD-associated mutations. Furthermore, mitochondrial complex-I-inhibiting toxins like MPTP and rotenone are known to cause Parkinson-like symptoms. At the heart of PD is alpha-synuclein (αS), a small synaptic protein that misfolds and aggregates to form the disease's hallmark Lewy bodies. The specific mechanisms through which aggregated αS exerts its neurotoxicity are still unknown; however, given the vital role of both αS and mitochondria to PD, an understanding of how αS influences mitochondrial maintenance may be essential to elucidating PD pathogenesis and discovering future therapeutic targets. Here, the current knowledge of the relationship between αS and mitochondrial quality control pathways in PD is reviewed, highlighting recent findings regarding αS effects on mitochondrial biogenesis, dynamics, and autophagy.

Mitochondrial quality control: the real dawn of intervertebral disc degeneration?

Intervertebral disc degeneration is the most common disease in chronic musculoskeletal diseases and the main cause of low back pain, which seriously endangers social health level and increases people's economic burden. Disc degeneration is characterized by NP cell apoptosis, extracellular matrix degradation and disc structure changes. It progresses with age and under the influence of mechanical overload, oxidative stress and genetics. Mitochondria are not only the energy factories of cells, but also participate in a variety of cellular functions such as calcium homeostasis, regulation of cell proliferation, and control of apoptosis. The mitochondrial quality control system involves many mechanisms such as mitochondrial gene regulation, mitochondrial protein import, mitophagy, and mitochondrial dynamics. A large number of studies have confirmed that mitochondrial dysfunction is a key factor in the pathological mechanism of aging and intervertebral disc degeneration, and balancing mitochondrial quality control is extremely important for delaying and treating intervertebral disc degeneration. In this paper, we first demonstrate the molecular mechanism of mitochondrial quality control in detail by describing mitochondrial biogenesis and mitophagy. Then, we describe the ways in which mitochondrial dysfunction leads to disc degeneration, and review in detail the current research on targeting mitochondria for the treatment of disc degeneration, hoping to draw inspiration from the current research to provide innovative perspectives for the treatment of disc degeneration.

Depressed TFAM promotes acetaminophen-induced hepatotoxicity regulated by DDX3X-PGC1α-NRF2 signaling pathway

BACKGROUND

Acetaminophen (APAP)-induced acute liver injury (AILI) is the most prevalent cause of acute liver failure and mitochondrial dysfunction plays a dominant role in the pathogenesis of AILI. Mitochondrial transcription factor A (TFAM) is an important marker for maintaining mitochondrial functional homeostasis, but its functions in AILI are unclear. This study aimed to investigate the function of TFAM and its regulatory molecular mechanism in the progression of AILI.

METHODS

The roles of TFAM and DEAD (Asp-Glu-Ala-Asp) box polypeptide 3 X-linked (DDX3X) in AILI were determined with TFAM overexpression and DDX3X knockdown, respectively.

RESULTS

TFAM expression was suppressed in AILI patients. TFAM overexpression alleviated liver necrosis and mitochondrial dysfunction. Treatment of the AILI mice model with N-acetylcysteine (NAC), a drug used to treat APAP overdose, resulted in significant TFAM activation. In vivo experiments confirmed that TFAM expression was negatively regulated by DDX3X. Mechanistic studies showed that nuclear respiratory factor 2 (NRF-2), a key regulator of TFAM, was selectively activated after DDX3X knockdown via activated peroxisome proliferator-activated receptor γ coactivator 1 (PGC-1α), in vivo and in vitro.

CONCLUSIONS

This study demonstrates that depressed hepatic TFAM plays a key role in the pathogenesis of AILI, which is regulated by the DDX3X-PGC1α-NRF2 signaling pathway.

Molecular pathways involved in the control of contractile and metabolic properties of skeletal muscle fibers as potential therapeutic targets for Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is caused by mutations in the gene encoding dystrophin, a subsarcolemmal protein whose absence results in increased susceptibility of the muscle fiber membrane to contraction-induced injury. This results in increased calcium influx, oxidative stress, and mitochondrial dysfunction, leading to chronic inflammation, myofiber degeneration, and reduced muscle regenerative capacity. Fast glycolytic muscle fibers have been shown to be more vulnerable to mechanical stress than slow oxidative fibers in both DMD patients and DMD mouse models. Therefore, remodeling skeletal muscle toward a slower, more oxidative phenotype may represent a relevant therapeutic approach to protect dystrophic muscles from deterioration and improve the effectiveness of gene and cell-based therapies. The resistance of slow, oxidative myofibers to DMD pathology is attributed, in part, to their higher expression of Utrophin; there are, however, other characteristics of slow, oxidative fibers that might contribute to their enhanced resistance to injury, including reduced contractile speed, resistance to fatigue, increased capillary density, higher mitochondrial activity, decreased cellular energy requirements. This review focuses on signaling pathways and regulatory factors whose genetic or pharmacologic modulation has been shown to ameliorate the dystrophic pathology in preclinical models of DMD while promoting skeletal muscle fiber transition towards a slower more oxidative phenotype.

PGC-1α drives small cell neuroendocrine cancer progression toward an ASCL1-expressing subtype with increased mitochondrial capacity

Adenocarcinomas from multiple tissues can converge to treatment-resistant small cell neuroendocrine (SCN) cancers composed of ASCL1, POU2F3, NEUROD1, and YAP1 subtypes. We investigated how mitochondrial metabolism influences SCN cancer (SCNC) progression. Extensive bioinformatics analyses encompassing thousands of patient tumors and human cancer cell lines uncovered enhanced expression of proliferator-activatedreceptor gamma coactivator 1-alpha (PGC-1α), a potent regulator of mitochondrial oxidative phosphorylation (OXPHOS), across several SCNCs. PGC-1α correlated tightly with increased expression of the lineage marker Achaete-scute homolog 1, (ASCL1) through a positive feedback mechanism. Analyses using a human prostate tissue-based SCN transformation system showed that the ASCL1 subtype has heightened PGC-1α expression and OXPHOS activity. PGC-1α inhibition diminished OXPHOS, reduced SCNC cell proliferation, and blocked SCN prostate tumor formation. Conversely, PGC-1α overexpression enhanced OXPHOS, validated by small-animal Positron Emission Tomography mitochondrial imaging, tripled the SCN prostate tumor formation rate, and promoted commitment to the ASCL1 lineage. These results establish PGC-1α as a driver of SCNC progression and subtype determination, highlighting metabolic vulnerabilities in SCNCs across different tissues.