Diet Based on Pereskia aculeata Miller Flour Increases Muscle Volume and Modulates the Expression of Myokines in Mice Subjected to Resistance Training

The study aimed to evaluate the effects of Pereskia aculeata Miller (ora-pro-nobis [OPN]) flour on body and biochemical parameters, thermogenic activity, and molecular expression of markers in the muscle tissue of mice subjected to resistance training (RT). Twelve mice were randomly assigned to two groups (n=6 animals/group): G1: control (Control) fed a standard diet + RT and G2: experimental (OPN) fed a diet based on OPN flour + RT. The RT consisted of a 6-week program using a vertical ladder combined with a fixed weight attached to the animal. Several parameters were measured, including assessment of body composition, biochemical markers, thermogenic activity, and molecular (mRNA expression of interleukin (IL)-6, fibronectin type III domain-containing protein 5 (FNDC5), peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), nuclear respiratory factor 1 (NRF1), and mitochondrial transcription factor A (TFAM). The OPN group exhibited a decrease in body weight and visceral adiposity, higher energy expenditure, and lipid oxidation rate. In addition, it was observed an increase in muscle volume and in mRNA expression levels of IL-6, FNDC5, PGC-1α, and TFAM. These findings suggest that OPN flour could be a nutritional option to enhance performance in RT.

The Application Potential of the Regulation of Tregs Function by Irisin in the Prevention and Treatment of Immune-Related Diseases

Irisin is a muscle factor induced by exercise, generated through the proteolytic cleavage of the membrane protein fibronectin type III domain-containing protein 5 (FNDC-5). Numerous studies have shown that irisin plays a significant role in regulating glucose and lipid metabolism, inhibiting oxidative stress, reducing systemic inflammatory responses, and providing neuroprotection. Additionally, irisin can exert immunomodulatory functions by regulating regulatory T cells (Tregs). Tregs are a highly differentiated subset of mature T cells that play a key role in maintaining self-immune homeostasis and are closely related to infections, inflammation, immune-related diseases, and tumors. Irisin exerts persistent positive effects on Treg cell functions through various mechanisms, including regulating Treg cell differentiation and proliferation, improving their function, modulating the balance of immune cells, increasing the production of anti-inflammatory cytokines, and enhancing metabolic functions, thereby helping to maintain immune homeostasis and prevent immune-related diseases. As an important myokine, irisin interacts with receptors on the cell membrane, activating multiple intracellular signaling pathways to regulate cell metabolism, proliferation, and function. Although the specific receptor for irisin has not been fully identified, integrins are considered potential receptors. Irisin activates various signaling pathways, including AMPK, MAPK, and PI3K/Akt, through integrin receptors, thereby exerting multiple biological effects. These research findings provide important clues for understanding the mechanisms of irisin's action and theoretical basis for its potential applications in metabolic diseases and immunomodulation. This article reviews the relationship between irisin and Tregs, as well as the research progress of irisin in immune-related diseases such as multiple sclerosis, myasthenia gravis, acquired immune deficiency syndrome, type 1 diabetes, sepsis, and rheumatoid arthritis. Studies have revealed that irisin plays an important role in immune regulation by improving the function of Tregs, suggesting its potential application value in the treatment of immune-related diseases.

Targeting the AMPK/Nrf2 Pathway: A Novel Therapeutic Approach for Acute Lung Injury

ALI(acute lung injury) is a severe respiratory dysfunction caused by various intrapulmonary and extrapulmonary factors. It is primarily characterized by oxidative stress and affects the integrity of the pulmonary barrier. In severe cases, ALI can progress to ARDS(acute respiratory distress syndrome), a condition that poses a serious threat to the lives of affected patients. To date, the etiological mechanisms underlying ALI remain elusive, and available therapeutic options are quite limited. AMPK(AMP-activated protein kinase), an essential serine/threonine protein kinase, performs a pivotal function in the regulation of cellular energy levels and cellular regulatory mechanisms, including the detection of redox signals and mitigating oxidative stress. Meanwhile, Nrf2(nuclear factor erythroid 2-related factor 2), a critical transcription factor, alleviates inflammation and oxidative responses by interacting with multiple signaling pathways and contributing to the modulation of oxidative enzymes associated with inflammation and programmed cell death. Indeed, AMPK induces the dissociation of Nrf2 from Keap1(kelch-like ECH-associated protein-1) and facilitates its translocation into the nucleus to trigger the transcription of downstream antioxidant genes, ultimately suppressing the expression of inflammatory cells in the lungs. Given their roles, AMPK and Nrf2 hold promise as novel treatment targets for ALI. This study aimed to summarise the current status of research on the AMPK/Nrf2 signaling pathway in ALI, encompassing recently reported natural compounds and drugs that can activate the AMPK/Nrf2 signaling pathway to alleviate lung injury, and provide a theoretical reference for early intervention in lung injury and future research on lung protection.

GPCR-mediated regulation of beige adipocyte formation: Implications for obesity and metabolic health

Obesity and its associated complications pose a significant burden on health. The non-shivering thermogenesis (NST) and metabolic capacity properties of brown adipose tissue (BAT), which are distinct from those of white adipose tissue (WAT), in combating obesity and its related metabolic diseases has been well documented. However, beige adipose tissue, the third and relatively novel type of adipose tissue, which emerges in extensive presence of WAT and shares similar favorable metabolic properties with BAT, has garnered considerable attention in recent years. In this review, we focused on the role of G protein-coupled receptors (GPCRs), the largest receptor family and the most successful class of drug targets in humans, in the induction of beige adipocytes. More importantly, we highlight researchers' clinical treatment attempts to ameliorate obesity and other related metabolic diseases through the formation and activation of beige adipose tissue. In summary, this review provides valuable insights into the formation of beige adipose tissue and the involvement of GPCRs, based on the latest advancements in scientific research.

Imeglimin modulates mitochondria biology and facilitates mitokine secretion in 3T3-L1 adipocytes

AIMS

Imeglimin, a novel antidiabetic drug, has recently been reported to affect pancreatic β-cells and hepatocytes. Adipose tissue plays a crucial role in systemic metabolism. However, its effect on adipocytes remains unexplored. Herein, we investigated the effects of imeglimin on adipocytes, particularly in the mitochondria.

MAIN METHODS

The 3T3-L1 adipocytes were treated with imeglimin. Mitochondrial respiratory complex I activity and NAD+, NADH, and AMP levels were measured. Protein expression levels were determined by western blotting, mitochondrial DNA and mRNA expression levels were determined using quantitative polymerase chain reaction, and secreted adipocytokine and mitokine levels were determined using adipokine array and enzyme-linked immunosorbent assay.

KEY FINDINGS

Imeglimin inhibited complex I activity, decreased the NAD+/NADH ratio, and increased AMP levels, which were associated with the enhanced phosphorylation of AMP-activated protein kinase. In addition, imeglimin increased the mitochondrial DNA content and levels of mitochondrial transcription factor A and peroxisome proliferator-activated receptor-γ coactivator 1-α mRNA, which were abolished by Ly294002, a phosphoinositide 3-kinase inhibitor. Furthermore, imeglimin facilitated the expression levels of markers of the mitochondrial unfolded protein response, and the gene expression and secretion of two mitokines, fibroblast growth factor 21 and growth differentiation factor 15. The production of both mitokines was transcriptionally regulated and abolished by phosphoinositide 3-kinase and Akt inhibitors.

SIGNIFICANCE

Imeglimin modulates mitochondrial biology in adipocytes and may exert a mitohormetic effect through mitokine secretion.

Comparative effects of 8-week combined resistance exercise training and alternate-day calorie restriction on soluble epidermal growth factor receptor (sEGFR) and adipsin in obese men

This study investigated the combined effects of resistance exercise training (RET) and alternate-day calorie restriction (ADCR) on body composition, insulin resistance (IR), insulin resistance-related biomarkers (adipokine adipsin and hepatokine soluble EFGR), and weight loss in obese men. The findings revealed that RET + ADCR induced the greatest reductions in body weight, body fat percentage, and waist-to-hip ratio (WHR) compared to RET and ADCR alone (p < 0.05). Additionally, RET + ADCR resulted in the most significant improvements in IR, as measured by HOMA-IR, and in circulating levels of adipsin and soluble EFGR (p < 0.05). These findings suggest that combining RET and ADCR may be a more effective strategy for improving metabolic health, including body composition, IR, and metabolic tissues' functions, in obese men than either intervention alone.

Exploring the role of CBLB in acute myocardial infarction: transcriptomic, microbiomic, and metabolomic analyses

BACKGROUND

Specific alterations in gut microbiota and metabolites have been linked to AMI, with CBLB potentially playing an essential role. However, the precise interactions remain understudied, creating a significant gap in our understanding. This study aims to address this by exploring these interactions in CBLB-intervened AMI mice using transcriptome sequencing, 16 S rDNA, and non-targeted metabolite analysis.

METHODS

To probe the therapeutic potential and mechanistic underpinnings of CBLB overexpression in AMI, we utilized an integrative multi-omics strategy encompassing transcriptomics, metabolomics, and 16s rDNA sequencing. We selected these particular methods as they facilitate a holistic comprehension of the intricate interplay between the host and its microbiota, and the potential effects on the host's metabolic and gene expression profiles. The uniqueness of our investigation stems from utilizing a multi-omics approach to illuminate the role of CBLB in AMI, an approach yet unreported to the best of our knowledge. Our experimental protocol encompassed transfection of CBLB lentivirus-packaged vectors into 293T cells, followed by subsequent intervention in AMI mice. Subsequently, we conducted pathological staining, fecal 16s rDNA sequencing, and serum non-targeted metabolome sequencing. We applied differential expression analysis to discern differentially expressed genes (DEGs), differential metabolites, and differential microbiota. We performed protein-protein interaction analysis to identify core genes, and conducted correlation studies to clarify the relationships amongst these core genes, paramount metabolites, and key microbiota.

RESULTS

Following the intervention of CBLB in AMI, we observed a significant decrease in inflammatory cell infiltration and collagen fiber formation in the infarcted region of mice hearts. We identified key changes in microbiota, metabolites, and DEGs that were associated with this intervention. The findings revealed that CBLB has a significant correlation with DEGs, differential metabolites and microbiota, respectively. This suggests it could play a pivotal role in the regulation of AMI.

CONCLUSION

This study confirmed the potential of differentially expressed genes, metabolites, and microbiota in AMI regulation post-CBLB intervention. Our findings lay groundwork for future exploration of CBLB's role in AMI, suggesting potential therapeutic applications and novel research directions in AMI treatment strategies.

Dynamics of single-nuclei transcriptomic profiling of adipose tissue from diverse anatomical locations during mouse aging process

Adipose tissue plays critical roles in an individual's aging process. In this research, we use single-nucleus RNA sequencing to create highly detailed transcriptional maps of subcutaneous adipose tissue and visceral adipose tissue in young and aged mice. We comprehensively identify the various cell types within the white adipose tissue of mice, our study has elucidated seven distinct cell types within this tissue. Further analyses focus on adipocytes, fibro-adipogenic progenitors, and immune cells, revealing age-related declines in the synthetic metabolic activity of adipocytes, diminished immune regulation, and reduced maturation or proliferation of fibroblasts in undifferentiated adipocytes. We confirm the presence of distinct subpopulations of adipocytes, highlighting decreases in adipogenesis subgroups due to aging. Additionally, we uncover a reduction in immune cell subpopulations, driven by age-associated immune system dysregulation. Furthermore, pseudo-time analyses indicate that Adipocyte1 represents the 'nascent' phase of adipocyte development, while Adipocyte2 represents the 'mature' phase. We use cell-cell interaction to explore the age-dependent complexities of the interactions between FAPs and adipocytes, and observed increased expression of the inflammation-related Retn-Tlr4 interaction in older mice, while the anti-inflammatory Angpt1-Tek interaction was only detected in young mice. These transcriptional profiles serve as a valuable resource for understanding the functional genomics underlying metabolic disorders associated with aging in human adipose tissue.

MicroRNA-21 modulates brown adipose tissue adipogenesis and thermogenesis in a mouse model of polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS), the most common endocrine disorder in premenopausal women, is associated with increased obesity, hyperandrogenism, and altered brown adipose tissue (BAT) thermogenesis. MicroRNAs play critical functions in brown adipocyte differentiation and maintenance. We aim to study the role of microRNA-21 (miR-21) in altered energy homeostasis and BAT thermogenesis in a PCOS mouse model of peripubertal androgen exposure.

METHODS

Three-week-old miR-21 knockout (miR21KO) or wild-type (WT) female mice were treated with dihydrotestosterone (DHT) or vehicle for 90 days. Body composition was determined by EchoMRI. Energy expenditure (EE), oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory exchange ratio (RER) were measured by indirect calorimetry. Androgen receptor (AR), and markers of adipogenesis, de novo lipogenesis, angiogenesis, extracellular matrix remodeling, and thermogenesis were quantified by RT-qPCR and/or Western-blot.

RESULTS

MiR-21 ablation attenuated DHT-mediated increase in body weight while having no effect on fat or BAT mass. MiR-21 ablation attenuated DHT-mediated BAT AR upregulation. MiR-21 ablation did not alter EE; however, miR21KO DHT-treated mice have reduced VO2, VCO2, and RER. MiR-21 ablation reversed DHT-mediated decrease in food intake and increase in sleep time. MiR-21 ablation decreased some adipogenesis (Adipoq, Pparγ, and Cebpβ) and extracellular matrix remodeling (Mmp-9 and Timp-1) markers expression in DHT-treated mice. MiR-21 ablation abolished DHT-mediated increases in thermogenesis markers Cpt1a and Cpt1b, while decreasing CIDE-A expression.

CONCLUSIONS

Our findings suggest that BAT miR-21 may play a role in regulating DHT-mediated thermogenic dysfunction in PCOS. Modulation of BAT miR-21 levels could be a novel therapeutic approach for the treatment of PCOS-associated metabolic derangements.

Mitochondrial targeted antioxidants as potential therapy for huntington's disease

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an expansion in CAG repeat on huntington (Htt) gene, leading to a degeneration of GABAergic medium spiny neurons (MSNs) in the striatum, resulting in the generation of reactive oxygen species, and decrease antioxidant activity. These pathophysiological alterations impair mitochondrial functions, leading to an increase in involuntary hyperkinetic movement. However, researchers investigated the neuroprotective effect of antioxidants using various animal models. Still, their impact is strictly limited to curtailing oxidative stress and increasing the antioxidant enzyme in the brain, which is less effective in HD. Meanwhile, researchers discovered Mitochondria-targeted antioxidants (MTAXs) that can improve mitochondrial functions and antioxidant activity through the modulation of mitochondrial signaling pathways, including peroxisome proliferator-activated receptor (PPAR)-coactivator 1 (PGC-1α), dynamin-related protein 1 (Drp1), mitochondrial fission protein 1 (Fis1), and Silent mating type information regulation 2 homolog 1 (SIRT-1), showing neuroprotective effects in HD. The present review discusses the clinical and preclinical studies that investigate the neuroprotective effect of MTAXs (SS31, XJB-5-131, MitoQ, bezafibrate, rosiglitazone, meldonium, coenzyme Q10, etc.) in HD. This brief literature review will help to understand the relevance of MTAXs in HD and enlighten the importance of MTAXs in future drug discovery and development.

Transcriptomic Approaches to Cardiomyocyte-Biomaterial Interactions: A Review

Biomaterials, essential for supporting, enhancing, and repairing damaged tissues, play a critical role in various medical applications. This Review focuses on the interaction of biomaterials and cardiomyocytes, emphasizing the unique significance of transcriptomic approaches in understanding their interactions, which are pivotal in cardiac bioengineering and regenerative medicine. Transcriptomic approaches serve as powerful tools to investigate how cardiomyocytes respond to biomaterials, shedding light on the gene expression patterns, regulatory pathways, and cellular processes involved in these interactions. Emerging technologies such as bulk RNA-seq, single-cell RNA-seq, single-nucleus RNA-seq, and spatial transcriptomics offer promising avenues for more precise and in-depth investigations. Longitudinal studies, pathway analyses, and machine learning techniques further improve the ability to explore the complex regulatory mechanisms involved. This review also discusses the challenges and opportunities of utilizing transcriptomic techniques in cardiomyocyte-biomaterial research. Although there are ongoing challenges such as costs, cell size limitation, sample differences, and complex analytical process, there exist exciting prospects in comprehensive gene expression analyses, biomaterial design, cardiac disease treatment, and drug testing. These multimodal methodologies have the capacity to deepen our understanding of the intricate interaction network between cardiomyocytes and biomaterials, potentially revolutionizing cardiac research with the aim of promoting heart health, and they are also promising for studying interactions between biomaterials and other cell types.

FNDC5/Irisin in dementia and cognitive impairment: update and novel perspective

Epidemiological surveys show that the incidence of age-related dementia and cognitive impairment is increasing and it has been a heavy burden for society, families, and healthcare systems, making the preservation of cognitive function in an increasingly aging population a major challenge. Exercise is beneficial for brain health, and FDNC5/irisin, a new exercise-induced myokine, is thought to be a beneficial mediator to cognitive function and plays an important role in the crosstalk between skeletal muscle and brain. This review provides a critical assessment of the recent progress in both fundamental and clinical research of FDNC5/irisin in dementia and cognitive impairment-related disorders. Furthermore, we present a novel perspective on the therapeutic effectiveness of FDNC5/irisin in alleviating these conditions.

The Relationship Between Intramural Fat Accumulation and Sarcopenia on MR Enterography Exams in Patients with Crohn's Disease

Research on magnetic resonance enterography (MRE) and sarcopenia for assessing Crohn's disease (CD) is growing. Our study examined the connections between the presence of sarcopenia, intramural fat accumulation (IFA), and clinical, laboratory, and MRE findings.This retrospective study was conducted on 112 patients with suspected or diagnosed CD who underwent 3-tesla MRE. The study examined the correlation between sarcopenia-related parameters and MRE findings. Results of MRE exams and clinical and laboratory results were statistically analyzed. The Kruskal-Wallis, Pearson chi-square, and Fisher-Freeman-Halton tests were used for comparison.It was determined that patients with active inflammation on a chronic basis had more IFA than the others (p<0.001). There were positive relationships between IFA and intramural edema (p<0.001). There were positive correlations between IFA and high b-values and negative correlations with apparent diffusion coefficient values (p<0.05). Positively significant relationships were found between IFA and wall thickness, affected segment length, disease duration, and sedimentation values (p<0.05). Strong correlations were found between sarcopenia and the CD activity index as well as wall thickness (p<0.001/p=0.003). There was no significant relationship between steroid usage and other variables.The presence of IFA is associated with chronic inflammation. There was no clear relationship between steroid use and IFA. Our findings support the idea that sarcopenia is related to the activity of CD. Further comprehensive research is required on these subjects. · The usage of MR enterography for the management of CD is increasing day by day due to its advantages.. · There is a paucity of evidence regarding the relationship between sarcopenia and MR enterography findings in patients with CD.. · Intramural fat accumulation (IFA) is a sign of chronicity in patients with CD.. · The presence of IFA seems to be associated with active inflammation on a chronic basis.. · There was no clear relationship between steroid use and IFA.. · Algin O, Güneş YC, Cankurtaran RE et al. The Relationship Between Intramural Fat Accumulation and Sarcopenia on MR Enterography Exams in Patients with Crohn's Disease. Fortschr Röntgenstr 2024; DOI 10.1055/a-2330-8148.

Inquiry of the Metabolic Traits in Relationship with Daily Magnesium Intake: Focus on Type 2 Diabetic Population

Magnesium (Mg), an essential nutrient with a wide area of physiological roles, stands as a cofactor in over 600 enzymatic reactions involved in the synthesis of proteins and nucleic acids, DNA repair, neuromuscular functions, neuronal transmission, cardiac rhythm regulation, and the modulation of metabolic pathways, as well as acting as a natural blocker for the calcium channels. Our objective was to highlight the most recent clinical data with respect to daily Mg intake (DMI) and metabolic traits, particularly type 2 diabetes mellitus (DM). This was a PubMed-based review of the English-language medical papers across different key terms of search; the time frame was from January 2019 until April 2024. We included (clinically relevant) original studies and excluded cases reports, series, reviews, editorials, opinion, experimental studies, and non-human data as well as studies that did not specifically assessed DMI and only provided assays of serum Mg, studies on patients diagnosed with type 1 or secondary DM. A total of 30 studies were included and we organized the key findings into several sections as follows. Studies investigating DMI in relationship with the adherence to local recommendations in diabetic subjects (n = 2, one transversal and another retrospective cohort; N = 2823) found that most of them had lower DMI. Deficient DMI was correlated with the risk of developing/having DM across five studies (n = 5, one prospective and four of cross-sectional design; N = 47,166). An inverse correlation between DMI and DM prevalence was identified, but these data are presented amid a rather heterogeneous spectrum. Four novel studies (N = 7279) analysed the relationship between DMI and DM control according to various methods (HbA1c, fasting and postprandial glycaemia, and insulin); the association may be linear in diabetic subjects only at certain levels of DMI; additionally, the multifactorial influence on HBA1c should take into consideration this dietary determinant, as well, but there are no homogenous results. Three studies concerning DMI and diabetic complications (one cross-sectional, one prospective, and another case-control study) in terms of retinopathy (n = 1, N = 3794) and nephropathy (n = 2, N = 4805) suggested a lower DMI was associated with a higher risk of such complications. Additionally, two other studies (one prospective and one retrospective cohort) focused on mortality (N = 6744), which, taking only certain mortality indicators into consideration, might be decreased in the subgroups with a higher DMI. Seven studies (N = 30,610) analysed the perspective of DMI in the general population with the endpoint of different features amid glucose profile, particularly, insulin resistance. Concerning HOMA-IR, there were three confirmatory studies and one non-confirmatory, while fasting plasma glucose was highlighted as inversely correlated with a DMI (n = 1). The highest level of evidence regarding Mg supplementation effects on glucose metabolism stands on seven randomised controlled trials (N = 350). However, the sample size was reduced (from 14 to 86 individuals per study, either diabetic or pre-diabetic) and outcomes were rather discordant. These clinical aspects are essential from a multidisciplinary perspective and further trials are mandatory to address the current areas of discordant results.

The therapeutic potential of irisin to mitigate the risk of metabolic syndrome in postmenopausal women

Oestradiol withdrawal at menopause predisposes women to metabolic syndrome, a cluster of interrelated conditions including obesity, insulin resistance, dyslipidaemia and hypertension that together confer an increased risk of developing type 2 diabetes mellitus and cardiovascular disease. Hormone replacement therapies are commonly used to treat acute symptoms of the perimenopausal period, and whilst they have been associated with metabolic improvements in many studies, long-term use is considered unviable. Novel approaches are required to mitigate the risk of postmenopausal metabolic syndrome. In 2012, the exercise-inducible myokine irisin was isolated from the skeletal muscle of mice and identified to have anti-obesity and antidiabetic effects in vivo. Irisin is now recognised to exert pleiotropic action on cognitive, bone and metabolic health. There is accumulating evidence from in vitro and in vivo rodent studies that irisin can mitigate each component condition of metabolic syndrome. In postmenopausal women, independent associations have been observed between (a) exercise and plasma irisin concentration and (b) plasma irisin concentration and reduced incidence of metabolic syndrome. To date, however, no study has considered the mechanistic basis by which irisin, whether exercise-induced or exogenously administered, could reduce the incidence or severity of metabolic syndrome in postmenopausal women. This review aims to analyse the literature concerning the metabolic actions of irisin, with a focus on its therapeutic potential for metabolic syndrome driven by a state of oestradiol depletion. It evaluates the practicality of exercise as a therapy and discusses other irisin-based therapeutic strategies that may alleviate postmenopausal metabolic syndrome. Finally, it highlights areas where future research is required to advance knowledge of irisin's biological action such that it could be considered a viable candidate for clinical application.

Association of copy number variation in X chromosome-linked PNPLA4 with heterotaxy and congenital heart disease

BACKGROUND

Heterotaxy (HTX) is a thoracoabdominal organ anomaly syndrome and commonly accompanied by congenital heart disease (CHD). The aim of this study was to analyze rare copy number variations (CNVs) in a HTX/CHD cohort and to examine the potential mechanisms contributing to HTX/CHD.

METHODS

Chromosome microarray analysis was used to identify rare CNVs in a cohort of 120 unrelated HTX/CHD patients, and available samples from parents were used to confirm the inheritance pattern. Potential candidate genes in CNVs region were prioritized via the DECIPHER database, and PNPLA4 was identified as the leading candidate gene. To validate, we generated PNPLA4-overexpressing human induced pluripotent stem cell lines as well as pnpla4-overexpressing zebrafish model, followed by a series of transcriptomic, biochemical and cellular analyses.

RESULTS

Seventeen rare CNVs were identified in 15 of the 120 HTX/CHD patients (12.5%). Xp22.31 duplication was one of the inherited CNVs identified in this HTX/CHD cohort, and PNPLA4 in the Xp22.31 was a candidate gene associated with HTX/CHD. PNPLA4 is expressed in the lateral plate mesoderm, which is known to be critical for left/right embryonic patterning as well as cardiomyocyte differentiation, and in the neural crest cell lineage. Through a series of in vivo and in vitro analyses at the molecular and cellular levels, we revealed that the biological function of PNPLA4 is importantly involved in the primary cilia formation and function via its regulation of energy metabolism and mitochondria-mediated ATP production.

CONCLUSIONS

Our findings demonstrated a significant association between CNVs and HTX/CHD. Our data strongly suggested that an increased genetic dose of PNPLA4 due to Xp22.31 duplication is a disease-causing risk factor for HTX/CHD.

Gene expression and characterization of clonally derived murine embryonic brown and brite adipocytes

White adipocytes store energy, while brown and brite adipocytes release heat via nonshivering thermogenesis. In this study, we characterized two murine embryonic clonal preadipocyte lines, EB5 and EB7, each displaying unique gene marker expression profiles. EB5 cells differentiate into brown adipocytes, whereas EB7 cells into brite (also known as beige) adipocytes. To draw a comprehensive comparison, we contrasted the gene expression patterns, adipogenic capacity, as well as carbohydrate and lipid metabolism of these cells to that of F442A, a well-known white preadipocyte and adipocyte model. We found that commitment to differentiation in both EB5 and EB7 cells can be induced by 3-Isobutyl-1-methylxanthine/dexamethasone (Mix/Dex) and staurosporine/dexamethasone (St/Dex) treatments. Additionally, the administration of rosiglitazone significantly enhances the brown and brite adipocyte phenotypes. Our data also reveal the involvement of a series of genes in the transcriptional cascade guiding adipogenesis, pinpointing GSK3β as a critical regulator for both EB5 and EB7 adipogenesis. In a developmental context, we observe that, akin to brown fat progenitors, brite fat progenitors make their appearance in murine development by 11-12 days of gestation or potentially earlier. This result contributes to our understanding of adipocyte lineage specification during embryonic development. In conclusion, EB5 and EB7 cell lines are valuable for research into adipocyte biology, providing insights into the differentiation and development of brown and beige adipocytes. Furthermore, they could be useful for the characterization of drugs targeting energy balance for the treatment of obesity and metabolic diseases.

Peridroplet mitochondria are associated with the severity of MASLD and the prevention of MASLD by diethyldithiocarbamate

Mitochondria can contact lipid droplets (LDs) to form peridroplet mitochondria (PDM) which trap fatty acids in LDs by providing ATP for triglyceride synthesis, and prevent lipotoxicity. However, the role of PDM in metabolic dysfunction associated steatotic liver disease (MASLD) is not clear. Here, the features of PDM in dietary MASLD models with different severity in mice were explored. Electron microscope photographs show that LDs and mitochondria rarely come into contact with each other in normal liver. In mice fed with high-fat diet, PDM can be observed in the liver as early as the beginning of steatosis in hepatocytes. For the first time, we show that PDM in mouse liver varies with the severity of MASLD. PDM and cytosolic mitochondria (CM) were isolated from the liver tissue of MASLD and analyzed by quantitative proteomics. Compared with CM, PDM have enhanced mitochondrial respiration and ATP synthesis. Diethyldithiocarbamate (DDC) alleviates choline-deficient, L-amino acid-defined diet-induced MASLD, while increases PDM in the liver. Similarly, DDC promotes the contact of mitochondria-LDs in steatotic C3A cells in vitro. Meanwhile, DDC promotes triglyceride synthesis and improves mitochondrial dysfunction in MASLD. In addition, DDC upregulates perilipin 5 both in vivo and in vitro, which is considered as a key regulator in PDM formation. Knockout of Plin5 inhibits the contact of mitochondria-LDs induced by DDC in C3A cells. These results demonstrate that PDM might be associated with the progression of MASLD and the prevention of MASLD by DDC. The regulation of PDM might be a new pharmacological strategy for MASLD.

Activin E upregulates uncoupling protein 1 and fibroblast growth factor 21 in brown adipocytes

Activin E activates brown and beige adipocytes and has been controversially implicated as a factor that induces obesity and fatty liver. Here, we sought to address this controversial issue by producing recombinant human activin E to evaluate its effects on HB2 brown adipocytes in vitro. Activin E increased uncoupling protein 1 (Ucp1) and fibroblast growth factor 21 (Fgf21) mRNA expression in the adipocytes. This upregulation was suppressed by SB431542, an inhibitor of activin receptor-like kinase (Alk) TGF-β type I receptors. SB431542 also inhibited the activin E-induced phosphorylation of Smad2/3. A promoter assay using a CAGA-Luc reporter and Alk expression vectors revealed that activin E activated the TGF-β/activin pathway via Alk7. The upregulation of Ucp1 and Fgf21 mRNA might be mediated through Alk7 and Smad2/3 phosphorylation. Activin E is a potential stimulator of energy expenditure by activating brown adipocytes and highlights its potential as a therapeutic target for treating obesity.

Autophagy counters inflammation-driven glycolytic impairment in aging hematopoietic stem cells

Autophagy is central to the benefits of longevity signaling programs and to hematopoietic stem cell (HSC) response to nutrient stress. With age, a subset of HSCs increases autophagy flux and preserves regenerative capacity, but the signals triggering autophagy and maintaining the functionality of autophagy-activated old HSCs (oHSCs) remain unknown. Here, we demonstrate that autophagy is an adaptive cytoprotective response to chronic inflammation in the aging murine bone marrow (BM) niche. We find that inflammation impairs glucose uptake and suppresses glycolysis in oHSCs through Socs3-mediated inhibition of AKT/FoxO-dependent signaling, with inflammation-mediated autophagy engagement preserving functional quiescence by enabling metabolic adaptation to glycolytic impairment. Moreover, we show that transient autophagy induction via a short-term fasting/refeeding paradigm normalizes glycolytic flux and significantly boosts oHSC regenerative potential. Our results identify inflammation-driven glucose hypometabolism as a key driver of HSC dysfunction with age and establish autophagy as a targetable node to reset oHSC regenerative capacity.

Breast volume in non-obese females is related to breast adipose cell hypertrophy, inflammation, and COX2 expression

BACKGROUND

Breast hypertrophy seems to be a risk factor for breast cancer and the amount and characteristics of breast adipose tissue may play important roles. The main aim of this study was to investigate associations between breast volume in normal weight women and hypertrophic adipose tissue and inflammation.

METHODS

Fifteen non-obese women undergoing breast reduction surgery were examined. Breast volume was measured with plastic cups and surgery was indicated if the breast was 800 ml or larger according to Swedish guidelines. We isolated adipose cells from the breasts and ambient subcutaneous tissue to measure cell size, cell inflammation and other known markers of risk of developing breast cancer including COX2 gene activation and MAPK, a cell proliferation regulator.

RESULTS

Breast adipose cell size was characterized by cell hypertrophy and closely related to breast volume. The breast adipose cells were also characterized by being pro-inflammatory with increased IL-6, IL-8, IL-1β, CCL-2, TNF-a and an increased marker of cell senescence GLB1/β-galactosidase, commonly increased in hypertrophic adipose tissue. The prostaglandin synthetic marker COX2 was also increased in the hypertrophic cells and COX2 has previously been shown to be an important marker of risk of developing breast cancer. Interestingly, the phosphorylation of the proliferation marker MAPK was also increased in the hypertrophic adipose cells.

CONCLUSION

Taken together, these findings show that increased breast volume in non-obese women is associated with adipose cell hypertrophy and dysfunction and characterized by increased inflammation and other markers of increased risk for developing breast cancer.

TRIAL REGISTRATION

Projektdatabasen FoU i VGR, project number: 249191 (https://www.researchweb.org/is/vgr/project/249191).

Engineering an energy-dissipating hybrid tissue in vivo for obesity treatment

Obesity is a global health challenge with limited therapeutic solutions. Here, we demonstrate the engineering of an energy-dissipating hybrid tissue (EDHT) in the body for weight control. EDHT is constructed by implanting a synthetic gel matrix comprising immunomodulatory signals and functional cells into the recipient mouse. The immunomodulatory signals induce the host stromal cells to create an immunosuppressive niche that protects the functional cells, which are overexpressing the uncoupling protein 1 (UCP1), from immune rejection. Consequently, these endogenous and exogenous cells co-develop a hybrid tissue that sustainedly produces UCP1 to accelerate the host's energy expenditure. Systematic experiments in high-fat diet (HFD) and transgenic (ob/ob) mice show that EDHT efficiently reduces body weight and relieves obesity-associated pathological conditions. Importantly, an 18-month observation for safety assessment excludes cell leakage from EDHT and reports no adverse physiological responses. Overall, EDHT demonstrates convincing efficacy and safety in controlling body weight.

Total Gestational Weight Gain Is Explained by Leptin and Body Fat, Regardless of Pre-Pregnancy Body Mass Index and Other Adipokines, in Mexican Adolescents

Pre-pregnancy body mass index (pBMI) is a predictor of gestational weight gain (GWG). However, other factors, such as adipokines and inflammation markers, may also be associated with GWG. The aim of the study was to determine the association of leptin, adiponectin, irisin, and C-reactive protein, with GWG in adolescents. A longitudinal study was conducted from 2018 to 2023 in adolescents with a clinically healthy pregnancy. The assessments included sociodemographic and clinical data, pBMI, percent of body fat, serum concentrations of leptin, adiponectin, irisin, and high-sensitivity C-reactive protein (hsCRP), and total GWG adequacy. Cox regression models were performed, the outcome variables were inadequate and excessive GWG. In 198 participants, being overweight/obesity was marginally associated with a protective effect against inadequate GWG (HR = 0.44, 95%CI = 0.18-1.06), regardless of maternal characteristics and adipokines. Leptin (HR = 1.014, 95%CI = 1.008-1.021), and body fat percent (HR = 1.11, 95%CI = 1.05-1.17) were associated with a higher risk of excessive GWG, independent of other maternal variables such as pBMI, while adiponectin was associated with a lower risk. These findings suggest that, in Mexican adolescents, adipose tissue and its adipokines during pregnancy may play a more significant role in the final GWG than body weight.

The metabolic benefits of thermogenic stimulation are preserved in aging

Adipose thermogenesis has been actively investigated as a therapeutic target for improving metabolic dysfunction in obesity. However, its applicability to middle-aged and older populations, which bear the highest obesity prevalence in the US (approximately 40%), remains uncertain due to age-related decline in thermogenic responses. In this study, we investigated the effects of chronic thermogenic stimulation using the β3-adrenergic (AR) agonist CL316,243 (CL) on systemic metabolism and adipose function in aged (18-month-old) C57BL/6JN mice. Sustained β3-AR treatment resulted in reduced fat mass, increased energy expenditure, increased fatty acid oxidation and mitochondrial activity in adipose depots, improved glucose homeostasis, and a favorable adipokine profile. At the cellular level, CL treatment increased uncoupling protein 1 (UCP1)-dependent thermogenesis in brown adipose tissue (BAT). However, in white adipose tissue (WAT) depots, CL treatment increased glycerol and lipid de novo lipogenesis (DNL) and turnover suggesting the activation of the futile substrate cycle of lipolysis and reesterification in a UCP1-independent manner. Increased lipid turnover was also associated with the simultaneous upregulation of proteins involved in glycerol metabolism, fatty acid oxidation, and reesterification in WAT. Further, a dose-dependent impact of CL treatment on inflammation was observed, particularly in subcutaneous WAT, suggesting a potential mismatch between fatty acid supply and oxidation. These findings indicate that chronic β3-AR stimulation activates distinct cellular mechanisms that increase energy expenditure in BAT and WAT to improve systemic metabolism in aged mice. Our study provides foundational evidence for targeting adipose thermogenesis to improve age-related metabolic dysfunction.

Swimming exercise alleviates pathological bone features in curdlan-injected SKG mice by inducing irisin expression

This study assessed the therapeutic potential of swimming exercise in the curdlan-injected SKG mouse model and investigated the modulatory effects of irisin on inflammation. Curdlan-injected SKG were randomly assigned to either a home-cage group or a swimming group for 6 weeks. Changes in clinical arthritis scores and ankle thickness were measured weekly. Post-swimming program, mice were anesthetized for collection of vastus lateralis muscle and blood, which was followed by histological analysis, micro-CT imaging of the ankle joints, and the measurement of pro-inflammatory cytokines and irisin levels. Additionally, curdlan-injected SKG mice were intravenously injected with recombinant irisin protein and observed. Finally, serum levels of irisin in healthy control and ankylosing spondylitis (AS) patient groups were measured by ELISA. The swimming group of curdlan-injected SKG mice exhibited significant improvements in arthritis and enthesitis compared to the home-cage group. In particular, micro-CT and histological analyses revealed a notable reduction in pathological bone features in the swimming group compared to the home-cage group. Muscle endurance was also enhanced in the swimming group compared to the home-cage group, as determined by the wire-hanging test. Intriguingly, irisin levels not only were statistically increased in the swimming group but, also, TNF-α, IL-1β, and IL-6 levels were decreased. Additionally, injection of irisin protein slightly attenuated both arthritis and enthesitis in curdlan-injected SKG mice. Meanwhile, irisin serum levels were declined in AS patients. Overall, we found that swimming exercise attenuated pathological bone features in an AS animal model, potentially mediated by increased irisin serum levels with associated anti-inflammatory effects.

Lipid-associated macrophages reshape BAT cell identity in obesity

Obesity and type 2 diabetes cause a loss in brown adipose tissue (BAT) activity, but the molecular mechanisms that drive BAT cell remodeling remain largely unexplored. Using a multilayered approach, we comprehensively mapped a reorganization in BAT cells. We uncovered a subset of macrophages as lipid-associated macrophages (LAMs), which were massively increased in genetic and dietary model of BAT expansion. LAMs participate in this scenario by capturing extracellular vesicles carrying damaged lipids and mitochondria released from metabolically stressed brown adipocytes. CD36 scavenger receptor drove LAM phenotype, and CD36-deficient LAMs were able to increase brown fat genes in adipocytes. LAMs released transforming growth factor β1 (TGF-β1), which promoted the loss of brown adipocyte identity through aldehyde dehydrogenase 1 family member A1 (Aldh1a1) induction. These findings unfold cell dynamic changes in BAT during obesity and identify LAMs as key responders to tissue metabolic stress and drivers of loss of brown adipocyte identity.

Impact of different hormones on the regulation of nitric oxide in diabetes

Polymetabolic syndrome achieved pandemic proportions and dramatically influenced public health systems functioning worldwide. Chronic vascular complications are the major contributors to increased morbidity, disability, and mortality rates in diabetes patients. Nitric oxide (NO) is among the most important vascular bed function regulators. However, NO homeostasis is significantly deranged in pathological conditions. Additionally, different hormones directly or indirectly affect NO production and activity and subsequently act on vascular physiology. In this paper, we summarize the recent literature data related to the effects of insulin, estradiol, insulin-like growth factor-1, ghrelin, angiotensin II and irisin on the NO regulation in physiological and diabetes circumstances.

Diverse associations between pancreatic intra-, inter-lobular fat and the development of type 2 diabetes in overweight or obese patients

Pancreatic fat is associated with obesity and type 2 diabetes mellitus (T2DM); however, the relationship between different types of pancreatic fat and diabetes status remains unclear. Therefore, we aimed to determine the potential of different types of pancreatic fat accumulation as a risk factor for T2DM in overweight or obese patients. In total, 104 overweight or obese patients were recruited from January 2020 to December 2022. The patients were divided into three groups: normal glucose tolerance (NGT), impaired fasting glucose or glucose tolerance (IFG/IGT), and T2DM. mDixon magnetic resonance imaging (MRI) was used to detect pancreatic fat in all three groups of patients. The pancreatic head fat (PHF), body fat (PBF), and tail fat (PTF) in the IFG/IGT group were 21, 20, and 31% more than those in the NGT group, respectively. PHF, PBF, and PTF were positively associated with glucose metabolic dysfunction markers in the NGT group, and inter-lobular fat volume (IFV) was positively associated with these markers in the IFG/IGT group. The areas under the receiver operating characteristic curves for PHF, PBF, and PTF (used to evaluate their diagnostic potential for glucose metabolic dysfunction) were 0.73, 0.73, and 0.78, respectively, while those for total pancreatic volume (TPV), pancreatic parenchymal volume, IFV, and IFV/TPV were 0.67, 0.67, 0.66, and 0.66, respectively. These results indicate that intra-lobular pancreatic fat, including PHF, PTF, and PBF, may be a potential independent risk factor for the development of T2DM. Additionally, IFV exacerbates glucose metabolic dysfunction. Intra-lobular pancreatic fat indices were better than IFV for the diagnosis of glucose metabolic dysfunction.

The role and mechanism of pyroptosis and potential therapeutic targets in non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is a clinical pathological syndrome characterized by the excessive accumulation of fat within liver cells, which can progress to end-stage liver disease in severe cases, posing a threat to life. Pyroptosis is a distinct, pro-inflammatory form of cell death, differing from traditional apoptosis. In recent years, there has been growing research interest in the association between pyroptosis and NAFLD, encompassing the mechanisms and functions of pyroptosis in the progression of NAFLD, as well as potential therapeutic targets. Controlled pyroptosis can activate immune cells, eliciting host immune responses to shield the body from harm. However, undue activation of pyroptosis may worsen inflammatory responses, induce cellular or tissue damage, disrupt immune responses, and potentially impact liver function. This review elucidates the involvement of pyroptosis and key molecular players, including NOD-like receptor thermal protein domain associated protein 3(NLRP3) inflammasome, gasdermin D (GSDMD), and the caspase family, in the pathogenesis and progression of NAFLD. It emphasizes the promising prospects of targeting pyroptosis as a therapeutic approach for NAFLD and offers valuable insights into future directions in the field of NAFLD treatment.

CB2 stimulation of adipose resident ILC2s orchestrates immune balance and ameliorates type 2 diabetes mellitus

Development of type 2 diabetes mellitus (T2DM) is associated with low-grade chronic type 2 inflammation and disturbance of glucose homeostasis. Group 2 innate lymphoid cells (ILC2s) play a critical role in maintaining adipose homeostasis via the production of type 2 cytokines. Here, we demonstrate that CB2, a G-protein-coupled receptor (GPCR) and member of the endocannabinoid system, is expressed on both visceral adipose tissue (VAT)-derived murine and human ILC2s. Moreover, we utilize a combination of ex vivo and in vivo approaches to explore the functional and therapeutic impacts of CB2 engagement on VAT ILC2s in a T2DM model. Our results show that CB2 stimulation of ILC2s protects against insulin-resistance onset, ameliorates glucose tolerance, and reverses established insulin resistance. Our mechanistic studies reveal that the therapeutic effects of CB2 are mediated through activation of the AKT, ERK1/2, and CREB pathways on ILC2s. The results reveal that the CB2 agonist can serve as a candidate for the prevention and treatment of T2DM.

The Role of PGC-1α in Aging Skin Barrier Function

Skin provides a physical and immune barrier to protect the body from foreign substances, microbial invasion, and desiccation. Aging reduces the barrier function of skin and its rate of repair. Aged skin exhibits decreased mitochondrial function and prolonged low-level inflammation that can be seen in other organs with aging. Peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1α (PGC-1α), an important transcriptional coactivator, plays a central role in modulating mitochondrial function and antioxidant production. Mitochondrial function and inflammation have been linked to epidermal function, but the mechanisms are unclear. The aim of this review is to discuss the mechanisms by which PGC-1α might exert a positive effect on aged skin barrier function. Initially, we provide an overview of the function of skin under physiological and aging conditions, focusing on the epidermis. We then discuss mitochondrial function, oxidative stress, cellular senescence, and inflamm-aging, the chronic low-level inflammation observed in aging individuals. Finally, we discuss the effects of PGC-1α on mitochondrial function, as well as the regulation and role of PGC-1α in the aging epidermis.

UCP1 expression in human brown adipose tissue is inversely associated with cardiometabolic risk factors

OBJECTIVE

Brown adipose tissue (BAT) is a therapeutic target for obesity. 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) is commonly used to quantify human BAT mass and activity. Detectable 18F-FDG uptake by BAT is associated with reduced prevalence of cardiometabolic disease. However, 18F-FDG uptake may not always be a reliable marker of BAT thermogenesis, for example, insulin resistance may reduce glucose uptake. Uncoupling protein 1 (UCP1) is the key thermogenic protein in BAT. Therefore, we hypothesised that UCP1 expression may be altered in individuals with cardiometabolic risk factors.

METHODS

We quantified UCP1 expression as an alternative marker of thermogenic capacity in BAT and white adipose tissue (WAT) samples (n = 53) and in differentiated brown and white pre-adipocytes (n = 85).

RESULTS

UCP1 expression in BAT, but not in WAT or brown/white differentiated pre-adipocytes, was reduced with increasing age, obesity, and adverse cardiometabolic risk factors such as fasting glucose, insulin, and blood pressure. However, UCP1 expression in BAT was preserved in obese subjects of <40 years of age. To determine if BAT activity was also preserved in vivo, we undertook a case-control study, performing 18F-FDG scanning during mild cold exposure in young (mean age ∼22 years) normal weight and obese volunteers. 18F-FDG uptake by BAT and BAT volume were similar between groups, despite increased insulin resistance.

CONCLUSION

18F-FDG uptake by BAT and UCP1 expression are preserved in young obese adults. Older subjects retain precursor cells with the capacity to form new thermogenic adipocytes. These data highlight the therapeutic potential of BAT mass expansion and activation in obesity.

The Effect of Exercise on Mesenchymal Stem Cells and their Application in Obesity Treatment

Mesenchymal stem cells (MSCs) have demonstrated considerable potential in tissue repair and the treatment of immune-related diseases, but there are problems with homing efficiency during MSCs transplantation. Exercise, as an intervention, has been shown to have an important impact on the properties of MSCs. This review summarizes the effects of exercise on the properties (including proliferation, apoptosis, differentiation, and homing) of bone marrow-derived MSCs and adipose-derived MSCs. Studies indicated that exercise enhances bone marrow-derived MSCs proliferation, osteogenic differentiation, and homing while reducing adipogenic differentiation. For adipose-derived MSCs, exercise enhances proliferation and reduces adipogenic differentiation. In addition, studies have investigated the therapeutic effects of combined therapy of MSCs transplantation with exercise on diseases of the bone, cardiac, and nervous systems. The combined therapy improves tissue repair by increasing the homing of transplanted MSCs and cytokine secretion (such as neurotrophin 4). Furthermore, MSCs transplantation also has potential for the treatment of obesity. Although the effect is not significant in weight loss, MSCs transplantation shows effects in controlling blood glucose, improving dyslipidemia, reducing inflammation, and improving liver disease. Finally, the potential role of combined MSCs transplantation and exercise therapy in addressing obesity is discussed.

Differential expression of ADRB1 causes different responses to norepinephrine in adipocytes of Duroc-Landrace-Yorkshire pigs and min pigs

Research has shown that pigs from different regions exhibit varying responses to cold stimuli. Typically, cold stimuli induce browning of white adipose tissue mediated by adrenaline, promoting non-shivering thermogenesis. However, the molecular mechanisms underlying differential response of pig breeds to norepinephrine are unclear. The aim of this study was to investigate the differences and molecular mechanisms of the effects of norepinephrine (NE) treatment on adipocytes of Min pigs (a cold-resistant pig breed) and Duroc-Landrace-Yorkshire (DLY) pigs. Real time-qPCR, western blot, and immunofluorescence were performed following NE treatment on cell cultures of adipocytes originating from Min pigs (n = 3) and DLY pigs (n = 3) to assess the expressions of adipogenesis markers, beige fat markers, and mitochondrial biogenesis markers. The results showed that NE did not affect browning of adipocytes in DLY pigs, whereas promoted browning of adipocytes in Min pigs. Further, the expression of ADRB1 (Adrenoceptor Beta 1, ADRB1) was higher in subcutaneous adipose tissue and adipocytes of Min pigs than those of DLY pigs. Overexpression of ADRB1 in DLY pig adipocytes enhanced sensitivity to NE, exhibiting decreased adipogenesis markers, upregulated beige fat markers, and increased mitochondrial biogenesis. Conversely, adipocytes treated with ADRB1 antagonist in Min pigs resulted in decreased cellular sensitivity to NE. Further studies revealed differential CpG island methylation in ADRB1 promoter region, with lower methylation levels in Min pigs compared to DLY pigs. In conclusion, differential methylation of the ADRB1 promoter region leads to different ADRB1 expression, resulting in varying responsiveness to NE in adipocytes of two pig breeds. Our results provide new insights for further analysis of the differential cold responsiveness in pig breeds from different regions.

The role of pyroptosis in metabolism and metabolic disease

Pyroptosis is a lytic and pro-inflammatory form of regulated cell death characterized by the formation of membrane pores mediated by the gasdermin protein family. Two main activation pathways have been documented: the caspase-1-dependent canonical pathway and the caspase-4/5/11-dependent noncanonical pathway. Pyroptosis leads to cell swelling, lysis, and the subsequent release of inflammatory mediators, including interleukin-1β (IL-1β) and interleukin-18 (IL-18). Chronic inflammation is a well-established foundation and driver for the development of metabolic diseases. Conversely, metabolic pathway dysregulation can also induce cellular pyroptosis. Recent studies have highlighted the significant role of pyroptosis modulation in various metabolic diseases, including type 2 diabetes mellitus, obesity, and metabolic (dysfunction) associated fatty liver disease. These findings suggest that pyroptosis may serve as a promising novel therapeutic target for metabolic diseases. This paper reviews an in-depth study of the current advancements in understanding the role of pyroptosis in the progression of metabolic diseases.

Irisin attenuates acute glaucoma-induced neuroinflammation by activating microglia-integrin αVβ5/AMPK and promoting autophagy

Neuroinflammation, characterized by microglial activation and the release of multiple inflammatory mediators, is a key factor in acute glaucomatous injury leading to retinal ganglion cell (RGC) death and ultimately irreversible vision loss. Irisin, a novel exercise-induced myokine, has demonstrated anti-inflammatory activity in ischemia/reperfusion injuries across multiple organs and has displayed a significant neuroprotective role in experimental stroke disease models. This study examined the protective impact of irisin and investigated its potential mechanism involved in this process utilizing an acute ocular hypertension (AOH)-induced retinal injury model in mice and a microglia inflammation model induced by lipopolysaccharide (LPS). There was a transient downregulation of irisin in the retina after AOH injury, with parallel emergence of retinal neuroinflammation and RGC death. Irisin attenuated retinal and optic nerve damage and promotes the phenotypic conversion of microglia from M1 to M2. Mechanistically, irisin significantly upregulated the expression of integrin αVβ5, p-AMPK, and autophagy-related markers. Integrin αVβ5 was highly expressed on microglia but hardly expressed on RGC. The integrin αVβ5 inhibitor cilengitide, the AMPK inhibitor dorsomorphin, and the autophagy inhibitor 3-Methyladenine (3-MA) blocked the neuroprotective effects of irisin. Our results suggest irisin attenuates acute glaucoma-induced neuroinflammation and RGC death by activating integrin αVβ5/AMPK in microglia and promoting autophagy. It should be considered a potential neuroprotective therapy for acute glaucoma.

The effects of different durations of exposure to hypomagnetic field on the number of active mitochondria and ROS levels in the mouse hippocampus

Reactive oxygen species (ROS) are one of the potential molecules in response to a hypomagnetic field (HMF), and exposure to an HMF for eight weeks led to an increase in ROS levels in the whole hippocampus area in mice. ROS are mainly derived from the byproducts of mitochondrial metabolism. However, previous in vivo studies mostly focus on the influence of one time point of HMF exposure on the mouse hippocampus and lack comparative studies on the effects of different durations of HMF exposure on the mouse hippocampus. Here, we investigated the effects of different durations of HMF on the number of active mitochondria and ROS levels in mouse hippocampus. Compared with the geomagnetic field (GMF) group, we found that the number of active mitochondria in the hippocampus was significantly reduced during the sixth week of HMF exposure, whereas the number of active mitochondria was significantly reduced and the ROS levels was significantly increased during the eighth week of HMF exposure. The number of active mitochondria gradually decreased and ROS levels gradually increased in both GMF and HMF groups with prolonged exposure time. In addition, the expression level of the PGC-1α gene in the hippocampus, the main regulator of mitochondrial biogenesis, decreased significantly in the eighth week of HMF exposure. These results reveal that the changes in active mitochondria number and ROS levels were dependent on the durations of HMF exposure, and prolonged exposure to HMF exacerbates these changes.

Systems genetics analysis of human body fat distribution genes identifies adipocyte processes

Excess abdominal fat is a sexually dimorphic risk factor for cardio-metabolic disease and is approximated by the waist-to-hip ratio adjusted for body mass index (WHRadjBMI). Whereas this trait is highly heritable, few causal genes are known. We aimed to identify novel drivers of WHRadjBMI using systems genetics. We used two independent cohorts of adipose tissue gene expression and constructed sex- and depot-specific Bayesian networks to model gene-gene interactions from 8,492 genes. Using key driver analysis, we identified genes that, in silico and putatively in vitro, regulate many others. 51-119 key drivers in each network were replicated in both cohorts. In other cell types, 23 of these genes are found in crucial adipocyte pathways: Wnt signaling or mitochondrial function. We overexpressed or down-regulated seven key driver genes in human subcutaneous pre-adipocytes. Key driver genes ANAPC2 and RSPO1 inhibited adipogenesis, whereas PSME3 increased adipogenesis. RSPO1 increased Wnt signaling activity. In differentiated adipocytes, MIGA1 and UBR1 down-regulation led to mitochondrial dysfunction. These five genes regulate adipocyte function, and we hypothesize that they regulate fat distribution.

Exercise-induced muscle hormone "irisin" controls luteinizing hormone and follicle-stimulating hormone secretion by bovine gonadotrophs

Irisin is a hormone secreted by muscle in response to exercise. The irisin receptor (IrisinR) is a heterodimer of integrin alpha V (ITGAV) and integrin beta 5 (ITGB5) subunits. Since irisin may mediate some beneficial effects of exercise on animal reproduction, we tested the hypothesis that bovine gonadotrophs express IrisinR and irisin stimulates luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion by gonadotrophs. Reverse transcription polymerase chain reaction was used to detect the mRNA expression of both ITGAV and ITGB5 in the anterior pituitary glands (APs) of post pubertal heifers and mouse gonadotroph cell line "LβT2." Western blotting was used to detect protein expression in bovine APs. Immunofluorescence microscopy, utilizing the same antibody, visualized IrisinR on the plasma membrane of majority of gonadotrophs. We prepared AP cells from healthy postpubertal heifers, cultured them for 3.5 d, and treated them with increasing concentrations (0, 0.01, 0.1, 1, or 10 nM) of irisin for 5 min before either no treatment or gonadotropin-releasing hormone (GnRH) stimulation. After 2 h, media were harvested for LH and FSH assays. Irisin (0.1-10 nM) stimulated basal LH and FSH secretion, and these stimulatory effects were inhibited by the extracellular signal-regulated kinase or SMAD pathway inhibitors. In the presence of GnRH, irisin at 0.01-1 nM stimulated LH and FSH secretion. A higher dose of irisin (10 nM), however, suppressed the GnRH-induced LH and FSH levels. In conclusion, bovine gonadotrophs expressed IrisinR, and irisin controlled LH and FSH secretion from bovine gonadotrophs.

USP7 promotes cardiometabolic disorders and mitochondrial homeostasis dysfunction in diabetic mice via stabilizing PGC1β

Diabetic cardiomyopathy (DCM) is a major complication of diabetes and is characterized by left ventricular dysfunction. Currently, there is a lack of effective treatments for DCM. Ubiquitin-specific protease 7 (USP7) plays a key role in various diseases. However, whether USP7 is involved in DCM has not been established. In this study, we demonstrated that USP7 was upregulated in diabetic mouse hearts and NMCMs co-treated with HG+PA or H9c2 cells treated with PA. Abnormalities in diabetic heart morphology and function were reversed by USP7 silencing through conditional gene knockout or chemical inhibition. Proteomic analysis coupled with biochemical validation confirmed that PCG1β was one of the direct protein substrates of USP7 and aggravated myocardial damage through coactivation of the PPARα signaling pathway. USP7 silencing restored the expression of fatty acid metabolism-related proteins and restored mitochondrial homeostasis by inhibiting mitochondrial fission and promoting fusion events. Similar effects were also observed in vitro. Our data demonstrated that USP7 promoted cardiometabolic metabolism disorders and mitochondrial homeostasis dysfunction via stabilizing PCG1β and suggested that silencing USP7 may be a therapeutic strategy for DCM.

Single-nucleus RNA transcriptome profiling reveals murine adipose tissue endothelial cell proliferation gene networks involved in obesity development

Endothelial cells play an important role in the metabolism of adipose tissue (AT). This study aimed to analyze the changes that adipose tissue in AT endothelial cells undergo during the development of obesity, using single-nucleus RNA sequence (snRNA-seq). Mouse paraepididymal AT cells were subjected to snRNA-seq with the 10X Genomics platform. The cell types were then clustered using t-distributed stochastic neighbor embedding and unbiased computational informatics analyses. Protein-protein interactions network was established using the STRING database and visualized using Cytoscape. The dataset was subjected to differential gene enrichment analysis. In total, 21,333 cells acquired from 24 mouse paraepididymal AT samples were analyzed using snRNA-seq. This study identified 18 distinct clusters and annotated macrophages, fibroblasts, epithelial cells, T cells, endothelial cells, stem cells, neutrophil cells, and neutrophil cell types based on representative markers. Cluster 12 was defined as endothelial cells. The proportion of endothelial cells decreased with the development of obesity. Inflammatory factors, such as Vegfa and Prdm16 were upregulated in the medium obesity group but downregulated in the obesity group. Genes, such as Prox1, Erg, Flt4, Kdr, Flt1, and Pecam1 promoted the proliferation of AT endothelial cells and maintained the internal environment of AT. This study established a reference model and general framework for studying the mechanisms, biomarkers, and therapeutic targets of endothelial cell dysfunction-related diseases at the single-cell level.

Interrelation of adipose tissue macrophages and fibrosis in obesity

Obesity is characterized by adipose tissue expansion, extracellular matrix remodelling and unresolved inflammation that contribute to insulin resistance and fibrosis. Adipose tissue macrophages represent the most abundant class of immune cells in adipose tissue inflammation and could be key mediators of adipocyte dysfunction and fibrosis in obesity. Although macrophage activation states are classically defined by the M1/M2 polarization nomenclature, novel studies have revealed a more complex range of macrophage phenotypes in response to external condition or the surrounding microenvironment. Here, we discuss the plasticity of adipose tissue macrophages (ATMs) in response to their microenvironment in obesity, with special focus on macrophage infiltration and polarization, and their contribution to adipose tissue fibrosis. A better understanding of the role of ATMs as regulators of adipose tissue remodelling may provide novel therapeutic strategies against obesity and associated metabolic diseases.

[18F]F-AraG imaging reveals association between neuroinflammation and brown- and bone marrow adipose tissue

Brown and brown-like adipose tissues have attracted significant attention for their role in metabolism and therapeutic potential in diabetes and obesity. Despite compelling evidence of an interplay between adipocytes and lymphocytes, the involvement of these tissues in immune responses remains largely unexplored. This study explicates a newfound connection between neuroinflammation and brown- and bone marrow adipose tissue. Leveraging the use of [18F]F-AraG, a mitochondrial metabolic tracer capable of tracking activated lymphocytes and adipocytes simultaneously, we demonstrate, in models of glioblastoma and multiple sclerosis, the correlation between intracerebral immune infiltration and changes in brown- and bone marrow adipose tissue. Significantly, we show initial evidence that a neuroinflammation-adipose tissue link may also exist in humans. This study proposes the concept of an intricate immuno-neuro-adipose circuit, and highlights brown- and bone marrow adipose tissue as an intermediary in the communication between the immune and nervous systems. Understanding the interconnectedness within this circuitry may lead to advancements in the treatment and management of various conditions, including cancer, neurodegenerative diseases and metabolic disorders.

Sex-Specific Effects of THRβ Signaling on Metabolic Responses to High Fat Diet in Mice

Thyroid hormone (TH) plays a crucial role in regulating the functions of both bone and adipose tissue. Given that TH exerts its cholesterol-lowering effects in hepatic tissue through the TH receptor-β (TRβ), we hypothesized that TRβ agonist therapy using MGL3196 (MGL) would be effective in treating increased adiposity and bone loss in response to a 12-week high-fat diet (HFD) in adult C57BL/6J mice. Transcriptional and serum profiling revealed that HFD-induced leptin promoted weight gain in both males and females, but MGL only suppressed leptin induction and weight gain in males. In vitro studies suggest that estrogen suppresses MGL activity in adipocytes, indicating that estrogen might interfere with MGL-TRβ function. Compared to systemic adiposity, HFD reduced bone mass in male but not female mice. Paradoxically, MGL treatment reversed macroscopic bone mineral density loss in appendicular bones, but micro-CT revealed that MGL exacerbated HFD-induced trabecular bone loss, and reduced bone strength. In studies on the mechanisms for HFD effects on bone, we found that HFD induced Rankl expression in male femurs that was blocked by MGL. By ex vivo assays, we found that RANKL indirectly represses osteoblast lineage allocation of osteoprogenitors by induction of inflammatory cytokines TNFα, IL-1β, and CCL2. Finally, we found that MGL functions in both systemic adiposity and bone by nongenomic TRβ signaling, as HFD-mediated phenotypes were not rescued in TRβ147F knockout mice with normal genomic but defective nongenomic TRβ signaling. Our findings demonstrate that the negative effects of HFD on body fat and bone phenotypes are impacted by MGL in a gender-specific manner.

NLRP3 inflammasome: a key player in the pathogenesis of life-style disorders

Proinflammatory cytokines and chemokines play a crucial role in regulating the inflammatory response, which is essential for the proper functioning of our immune system. When infections or threats to the body's defense mechanisms are detected, the innate immune system takes the lead. However, an excessive inflammatory response can lead to the production of high concentrations of cytotoxic molecules, resulting in tissue damage. Inflammasomes are significant contributors to innate immunity, and one of the most extensively studied inflammasome complexes is NOD-like receptor 3 (NLRP3). NLRP3 has a wide range of recognition mechanisms that streamline immune activation and eliminate pathogens. These cytosolic multiprotein complexes are composed of effector, adaptor, and sensor proteins, which are crucial for identifying intracellular bacterial breakdown products and initiating an innate immune cascade. To understand the diverse behavior of NLRP3 activation and its significance in the development of lifestyle-related diseases, one must delve into the study of the immune response and apoptosis mediated by the release of proinflammatory cytokines. In this review, we briefly explore the immune response in the context of lifestyle associated disorders such as obesity, hyperlipidemia, diabetes, chronic respiratory disease, oral disease, and cardiovascular disease.

Association of Serum Adipsin Level with Insulin Resistance and Inflammatory Markers in Newly Diagnosed Type two Diabetes Mellitus Patients

Adipsin is an anti-inflammatory adipokines and its altered level was seen in obesity and type II DM. Our study investigated the clinical significance of serum adipsin levels as a risk marker for type 2 diabetes and its relationships with insulin resistance and various adipo-cytokines. The study included 110 treatment-naïve T2DM cases and 100 controls of similar age and gender from northern India. Clinical, biochemical, and anthropometric characteristics were all profiled. Serum adipo-cytokines were measured using ELISA methods. Adipsin was significantly inversely correlated with body mass index (BMI), waist circumference, fasting plasma glucose, glycated haemoglobin (HbA1C), total cholesterol (TC), triglyceride (TG), homeostasis model assessment-estimated insulin resistance (HOMA-IR), tumour necrosis factor- α (TNF-α) and interleulin-6 (IL-6) and positively correlated with high-density lipoprotein cholesterol (HDL-C) and homeostasis model assessment of β-cell function (HOMA-B) (P < 0.05). T2DM occurrence decreased with increasing concentration of adipsin with an odds ratio (OR) of 0.68 (95% CI = 0.58-0.79), P < 0.001. The area under curve (95% CI) for adipsin was 0.70 (0.63 to 0.76) with P < 0.001. The best cutoff value for adipsin to predict T2DM was < 5.50 µg/ml with 47.27% sensitivity and 82.00% specificity. FPG and WC were both independent predictors of serum adipsin levels. Our findings showed that high adipsin levels reduced the likelihood of T2DM and emerged as a potential risk marker in the prediction of T2DM.

Graphical Abstract

Female Psammomys obesus Are Protected from Circadian Disruption-Induced Glucose Intolerance, Cardiac Fibrosis and Adipocyte Dysfunction

Circadian disruption increases the development of cardiovascular disease and diabetes. We found that circadian disruption causes glucose intolerance, cardiac fibrosis and adipocyte tissue dysfunction in male sand rats, Psammomys obesus. Whether these effects occur in female P. obesus is unknown. Male and female P. obesus were fed a high energy diet and exposed to a neutral (12 light:12 dark, control) or short (5 light:19 dark, circadian disruption) photoperiod for 20 weeks. Circadian disruption impaired glucose tolerance in males but not females. It also increased cardiac perivascular fibrosis and cardiac expression of inflammatory marker Ccl2 in males, with no effect in females. Females had reduced proapoptotic Bax mRNA and cardiac Myh7:Myh6 hypertrophy ratio. Cardiac protection in females occurred despite reductions in the clock gene Per2. Circadian disruption increased adipocyte hypertrophy in both males and females. This was concomitant with a reduction in adipocyte differentiation markers Pparg and Cebpa in males and females, respectively. Circadian disruption increased visceral adipose expression of inflammatory mediators Ccl2, Tgfb1 and Cd68 and reduced browning marker Ucp1 in males. However, these changes were not observed in females. Collectively, our study show that sex differentially influences the effects of circadian disruption on glucose tolerance, cardiac function and adipose tissue dysfunction.

Reduced adipocyte glutaminase activity promotes energy expenditure and metabolic health

Glutamine and glutamate are interconverted by several enzymes and alterations in this metabolic cycle are linked to cardiometabolic traits. Herein, we show that obesity-associated insulin resistance is characterized by decreased plasma and white adipose tissue glutamine-to-glutamate ratios. We couple these stoichiometric changes to perturbed fat cell glutaminase and glutamine synthase messenger RNA and protein abundance, which together promote glutaminolysis. In human white adipocytes, reductions in glutaminase activity promote aerobic glycolysis and mitochondrial oxidative capacity via increases in hypoxia-inducible factor 1α abundance, lactate levels and p38 mitogen-activated protein kinase signalling. Systemic glutaminase inhibition in male and female mice, or genetically in adipocytes of male mice, triggers the activation of thermogenic gene programs in inguinal adipocytes. Consequently, the knockout mice display higher energy expenditure and improved glucose tolerance compared to control littermates, even under high-fat diet conditions. Altogether, our findings highlight white adipocyte glutamine turnover as an important determinant of energy expenditure and metabolic health.

Irisin as an emerging target in the regulation of reproductive functions in health and disease

Germ cells are highly conserved in the gonads, nurtured to either develop into a gamete or self-renew into a stem cell reserve. Preserving the germ cell pool and protecting the reproductive organs is essential for maintaining an individual's fertility. Several factors, including a sedentary lifestyle, pollutants, hormonal disruption, drugs, and a disease condition, have been shown to impair normal reproductive function. Irisin has recently been identified as an adipomyokine involved in modulating physiological functions based on the body's metabolic status. It is being studied for its role in various functions, including fertility. Findings show the localization of irisin in various parts of the reproductive axis, with the highest levels observed during puberty and pregnancy. This raises questions about its role and function in reproduction. Studies support irisin's role in protecting against disease-induced reproductive abnormalities and infertility. Therefore, the current review focuses on how irisin influences spermatogenesis and ovarian follicular development and plays a significant role in indirectly preserving the germ cell pool by protecting the gonads against oxidative stress and inflammation.

Human epicardial fat has a beige profile and contains higher type 2 innate lymphoid cells than subcutaneous fat

OBJECTIVE

Epicardial adipose tissue (EAT) is a visceral fat that has been associated with coronary artery disease and atrial fibrillation. Previous work has revealed that EAT exhibits beige features.

METHODS

First, a new pan-genomic microarray analysis was performed on previously collected paired human EAT and thoracic subcutaneous AT (thSAT) from the EPICAR study (n = 31) to decipher a specific immune signature and its link with browning genes. Then, adaptive (T and B cells) and innate lymphoid cell (ILC1, ILC2, and ILC3) immunophenotyping assay panels, including CD127, CD117, and prostaglandin D2 receptor 2, were performed on prospectively collected paired human multiorgan donors (n = 18; INTERFACE study).

RESULTS

In the EPICAR study, a positive correlation between the T helper cell subtype Th2 immune pathway and browning genes was found in EAT versus thSAT (r = 0.82; p < 0.0001). In the INTERFACE study, this correlation was also observed (r = 0.31; p = 0.017), and a preponderance of CD4+T cells, CD8+T cells, and a few B cells was observed in all ATs (p < 0.0001). An increase in ILCs was observed in visceral AT (VAT) (i.e., EAT + VAT; 30 ± 5 ILCs per gram of AT) compared with subcutaneous counterparts (i.e., thSAT + abdominal SAT; 8 ± 2 ILCs per gram of AT; p = 0.001), with ILC1 being the most frequent (ILC1 > ILC3 > ILC2). Numbers of ILCs per gram of AT correlated with several Th2 or browning genes (IL-13, TNF receptor superfamily member 9 [TNFRSF9], and alkaline phosphatase, biomineralization associated [ALPL]). Interestingly, a specific increase in EAT-ILC2 compared with other ATs was observed, including a significant proportion expressing CD69 and/or CD25 activation markers (97.9% ± 1.2%; p < 0.0001). Finally, more natural killer cells were observed in EAT + VAT than in thSAT + abdominal SAT (p = 0.01). Exclusion of patients with coronary artery disease in the EPICAR and INTERFACE studies did not modify the main findings. Gene expression phenotyping confirmed specific upregulation of Th2 pathway and browning genes (IL-33 and uncoupling protein 1 [UCP-1]) in EAT.

CONCLUSIONS

This is the first study, to our knowledge, to provide a comparison between innate and adaptive lymphoid cells in human EAT. Further studies are ongoing to decipher whether these cells could be involved in EAT beiging.