Accumulation of γδ T cells in visceral fat with aging promotes chronic inflammation

Female-specific associations of serum perfluoroalkyl and polyfluoroalkyl substances with sex hormonal/insulin dysregulation: An integrated population-based study

BACKGROUND

Ubiquitous perfluoroalkyl/polyfluoroalkyl substances (PFASs) exhibit sex-differential blood accumulation. However, sex- and age-specific links between PFASs and insulin-hormone dysregulation remain unknown.

METHODS

This population-based study utilized survey-weighted data from the National Health and Nutrition Examination Survey 2013-2016. Correlations between PFASs and sex hormone- or insulin-related indicators were assessed using a survey-weighted generalized linear model (SWGLM) for individual analyses and weighted quantile sum (WQS) regression for mixture analyses, stratified by sex and age. The mixture-related findings were validated with Bayesian kernel machine regression (BKMR) and further examined through stratification by menopausal status. Moreover, we investigated whether homeostatic model assessment of insulin resistance (HOMA-IR) mediated the relationships between sex hormones and monomethyl branched isomers of perfluorooctane sulfonate (Sm-PFOS) sex-specifically.

RESULTS

The following results persisted only in females. In SWGLM, linear perfluorooctanoate (n-PFOA) and homeostatic model assessment of β cell function (HOMA-β) were positively correlated in females, with this correlation strengthening in those aged ≥ 60. In WQS, PFAS mixture was positively associated with total testosterone/estradiol (TT/E2) and negatively associated with estradiol (E2) in females, but not in postmenopausal participants; the BKMR demonstrated trends consistent with prior findings. These associations intensified in females aged 20-59, with n-PFOA and perfluorohexane sulfonic acid (PFHxS) being main pollutants in the 20-39 and 40-59 age groups, respectively in WQS. The relationships between Sm-PFOS and both free androgen index and sex hormone-binding globulin (SHBG) were mediated by HOMA-IR.

CONCLUSIONS

This cross-sectional study reveals female-specific associations between PFASs and insulin-hormone imbalance, suggesting multifaceted influences of PFASs on female endocrinology.

Association of visceral fat metabolic score with bone mineral density and osteoporosis: a NHANES cross-sectional study

BACKGROUND

Metabolic Score for Visceral Fat (METS-VF) is commonly used as an indicator for assessing visceral fat metabolism. However, the relationship between METS-VF, Bone Mineral Density (BMD), and osteoporosis remains unclear in the American population.

METHODS

This study utilized cross-sectional data from the National Health and Nutrition Examination Survey (NHANES), including participants aged 20 years and older, from the survey cycles conducted between 2005 and 2010, 2013-2014, and 2017-2018. Multivariable weighted linear regression and logistic regression analyses were first applied to investigate the associations between the METS-VF, femoral BMD, and osteoporosis. In addition, subgroup interaction analyses were performed to evaluate the robustness of these associations. To address potential non-linear relationships, restricted cubic spline regression was employed. All statistical analyses were conducted using R software version 4.3.3. P values were two-tailed, with P < 0.05 considered statistically significant.

RESULTS

After adjusting for all covariates, the positive correlations between METS-VF and BMD measurements at all sites remained statistically significant (p < 0.001 & p for trend < 0.001). Multivariable logistic regression analysis indicated that, after adjusting for covariates related to osteoporosis, each one-unit increase in METS-VF was associated with a 63.1% reduction in the risk of developing osteoporosis. Moreover, the direction of the associations between METS-VF and both BMD and osteoporosis remained consistent across all subgroups, while restricted cubic spline (RCS) analyses suggested nonlinear relationships. The 5.82-7.35 METS-VF range yielded a mean 51.9% osteoporosis risk reduction (sustained ≥ 30% peak efficacy in 66.7% of participants).

CONCLUSIONS

METS-VF demonstrated a nonlinear positive association with BMD and a nonlinear inverse relationship with osteoporosis risk. Future studies should establish optimal biological thresholds of METS-VF for skeletal health.

CLINICAL TRIAL NUMBER

Not applicable.

Prognostic Value of Epicardial Adipose Tissue in Heart Failure With Mid-Range and Preserved Ejection Fraction: A Multicenter Study

BACKGROUND

Epicardial adipose tissue (EAT) accumulation is thought to play a role in the pathophysiology of heart failure (HF) with mid-range ejection fraction and HF with preserved ejection fraction, but its effect on outcome is unknown.

METHODS AND RESULTS

A total of 692 patients with HF with mid-range ejection fraction or HF with preserved ejection fraction who underwent cardiovascular magnetic resonance at 2 medical centers in China between October 2016 and October 2022 were included in this study. EAT volume and extracellular volume were calculated using cardiovascular magnetic resonance. The main outcome was the composite of all-cause mortality and first HF hospitalization. Of 692 participants, 41.3% were women. The mean age, body mass index, left ventricular ejection fraction, and EAT volume were 57.0 years, 27.2 kg/m2, 50.0%, and 67.1 mL/m2, respectively. During a median follow-up of 34 months, 169 patients (24.4%) died or were hospitalized for HF. EAT volume exhibited a strong unadjusted association with the composite outcome (hazard ratio per 1 mL/m2 [HR], 1.57 [95% CI, 1.40-1.76], P<0.001). After fully adjusting, EAT remained associated with the outcome (HR, 1.62 [95% CI, 1.42-1.86], P<0.001). We constructed a baseline multivariable model including comorbidities, New York Heart Association functional class, extracellular volume, age, body mass index, left ventricular ejection fraction, and N-terminal pro-brain natriuretic peptide. Addition of EAT volume to the baseline multivariable model significantly improved model performance (C statistic improvement: 0.711-0.760; P<0.001).

CONCLUSIONS

EAT accumulation is associated with an adverse prognosis in patients with HF with mid-range ejection fraction and those with HF with preserved ejection fraction. In addition, EAT provides incremental prognostic value beyond left ventricular ejection fraction and New York Heart Association class.

Analysis of COPD: Distinguishing Characteristics and Management of Smoking vs Never Smoking Patients

Background

Chronic obstructive pulmonary disease (COPD) is a significant public health issue characterized by gradually worsening airflow limitation. It is a leading cause of mortality and morbidity worldwide, yet research on COPD patients who have never smoked is limited. This study aims to document the demographic, symptomatic, and therapeutic characteristics of COPD patients receiving outpatient pulmonary care in Hungary, focusing on smoking history, and evaluate their distribution according to the GOLD A/B/E classification.

Methods

The study recorded demographic data, symptom severity, occurrence of severe and moderate exacerbations, treatment, comorbidities, quality of life, and COVID-19 vaccination status among COPD patients from November 2021 to January 2023. A total of 6974 patients were categorized into current smokers, former smokers, and never smokers.

Results

Patients had an average age of 67.2±8.9 years, with 48.2% male and 51.8% female. Of participants, 86.1% had a smoking history, while 13.9% had never smoked. COPD patients who had never smoked showed significantly better quality of life (CAT: 15.2±7.6 vs 15.8±6.9; p=0.006), oxygen saturation (SpO2%: 96.7±2.3 vs 95.8±2.4; p<0.001), higher body mass index (BMI: 29.4±5.9 vs 27.1±6.3; p<0.001), and better lung function (FEV1ref%: 67.9±20.7 vs 58.9±18.1; p<0.001) compared to smokers. However, non-smoking COPD patients had a higher frequency of comorbidities (3.5±2.2 vs 2.9±2.1; p<0.05). These differences may arise from complex genetic and environmental interactions.

Conclusion

COPD patients who have never smoked exhibited better quality of life, nutritional status, and lung function compared to smokers, indicating the need for tailored treatment approaches. Further long-term studies are essential to validate these differences in quality of life and lung function between smoking and non-smoking COPD patients.

Diosmin and Coenzyme q10: Synergistic histopathological and functional protection against doxorubicin-induced hepatorenal injury in rats

Doxorubicin (DOX) is a cytotoxic anthracycline used to treat a variety of cancers. Cardiotoxicity, hepatotoxicity, and nephrotoxicity are adverse effects of DOX, that limit prognosis. The study aims to determine if diosmin (DIOS) and coenzyme Q10 (CoQ10) alone or in combination protect rats against DOX-induced liver and kidney damage. Adult male rats were assigned randomly in five groups. An intraperitoneal injection of DOX (2.5 mg/kg) was given to the DOX group every other day for three weeks, whereas a normal control group received the vehicle. Diosmin group received oral DIOS (100 mg/kg), Co-Q10 group received oral CoQ10 (10 mg/kg) and combination group received oral DIOS and CoQ10 daily for three weeks concomitantly with DOX. Sera and tissues were obtained 24 hours after last DOX injection. Serum aspartate transaminase (AST), alanine transaminase (ALT), creatinine, urea, total bilirubin and direct bilirubin were detected with hepatic and renal reduced glutathione (GSH), malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α) and nuclear factor kappa-B (NF-κB). Histopathology and morphometry of liver and kidney were assessed. DOX exerted significant hepatorenal toxicity via elevation of liver and kidney functions, inducing oxidative stress by reducing GSH and elevating MDA, triggering renal and hepatic TNF-α and NF-kB. DIOS and CoQ10 modulated hepatic and renal functions, oxidative stress and inflammatory biomarkers. DIOS-CoQ10 combination treatment showed significant improvement in histopathology of liver and kidney along with morphometry compared to DOX group. In conclusion, combining DIOS and CoQ10 exhibited synergistic protective activity against DOX-induced hepatic and renal insult via their antioxidant and anti-inflammatory properties.

Overweight and obesity significantly increase colorectal cancer risk: a meta-analysis of 66 studies revealing a 25-57% elevation in risk

The incidence of colorectal cancer (CRC) has been steadily rising, and obesity has been identified as a significant risk factor. Numerous studies suggest a strong correlation between excess body weight and increased risk of CRC, but comprehensive quantification through pooled analysis remains limited. This study aims to systematically review and meta-analyze the existing literature to evaluate the association between obesity and CRC risk, considering variations across sex and study designs. A systematic literature search was conducted in PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science to identify randomized controlled trials and human clinical trials from 1992 to 2024. Statistical analysis was performed using the https://metaanalysisonline.com web application using a random effects model to estimate the pooled hazard rates (HR). Forest plots, funnel plots, and Z-score plots were utilized to visualize results. We identified 52 clinical trials and 14 case-control studies, encompassing a total of 83,251,050 and 236,877 subjects, respectively. The pooled analysis indicated that obesity significantly increased the prevalence of CRC (HR = 1.36, 95% CI = 1.24-1.48, p < 0.01). This effect was consistent across sexes, with HRs of 1.57 (95% CI = 1.38-1.78, p = 0.01) for males and 1.25 (95% CI = 1.14-1.38, p < 0.01) for females. Case-control studies specifically showed an effect, but with marginal significance only (HR = 1.27, 95% CI = 0.98-1.65, p = 0.07). The Z-score plot indicated the need for additional analysis in the case-control group. A significant heterogeneity was observed across studies in all four settings. This meta-analysis provides robust evidence that obesity is a significant risk factor for colorectal cancer, with an overall hazard rate indicating a 36% increased risk. The effect is pronounced across both sexes, with males showing a slightly higher risk compared to females. Although case-control studies showed a weaker association, the overall trend supports the link between obesity and CRC. These results underscore the importance of public health interventions aimed at reducing obesity to potentially lower the risk of colorectal cancer.

GDF3 promotes adipose tissue macrophage-mediated inflammation via altered chromatin accessibility during aging

Age-related susceptibility to sepsis and endotoxemia is poorly defined, although hyperactivation of the immune system and the expansion of the visceral adipose as an immunological reservoir are underlying features. Macrophages from older organisms exhibit substantial changes, including chronic NLRP3 inflammasome activation, genomic remodeling and a dysfunctional, amplified inflammatory response upon new exposure to pathogen. However, the mechanisms by which old macrophages maintain their inflammatory phenotype during endotoxemia remains elusive. We previously identified Gdf3 , a TGFβ superfamily cytokine, as a top-regulated gene by age and the NLRP3 inflammasome in adipose tissue macrophages (ATMs). Here, we demonstrate that endotoxemia increases inflammatory (CD11c + ) ATMs in a Gdf3- dependent manner in old mice. Lifelong systemic or myeloid-specific deletion of Gdf3 leads to reduced endotoxemia- induced inflammation, with decreased CD11c + ATMs and inflammatory cytokines, and protection from hypothermia. Moreover, acute blockade of Gdf3 using JQ1, a BRD4 inhibitor, phenocopies old mice with lifelong Gdf3- deficiency. We show that GDF3 promotes the inflammatory phenotype in ATMs by phosphorylating SMAD2/3. Mechanistically, the differential chromatin landscape of ATMs from old mice with or without myeloid-driven Gdf3 indicates that GDF3- SMAD2/3 signaling axis shifts the chromatin accessibility of ATMs towards an inflammatory state during aging. Furthermore, pharmaceutical inhibition of SMAD3 with a specific inhibitor of SMAD3 (SIS3) mimics Gdf3 deletion. SIS3 reduces endotoxemia-mediated inflammation with fewer CD11c + ATMs and less severe hypothermia in old, but not young mice, as well as reduced mortality. In human adipose tissue, age positively correlates with GDF3 level, while inflammation correlates with pSMAD2/3 level. Overall, these results highlight the importance of GDF3-SMAD2/3 axis in driving inflammation in older organisms and identify this signaling axis as a promising therapeutic target for mitigating endotoxemia-related inflammation in the aged.

Cross-talk between oxidative stress and lipid metabolism regulators reveals molecular clusters and immunological characterization in polycystic ovarian syndrome

BACKGROUND

Changes in the oxidative stress and lipid metabolism (OSLM) pathways play important roles in polycystic ovarian syndrome (PCOS) pathogenesis and development. Consequently, a systematic analysis of genes related to OSLM was conducted to identify molecular clusters and explore new biomarkers that are helpful for the diagnostic of PCOS.

METHODS

Gene expression and clinical data from 22 PCOS women and 14 normal women were obtained from the GEO database (GSE34526, GSE95728, and GSE106724). Consensus clustering identified OSLM-related molecular clusters, and WGCNA revealed co-expression patterns. The immune microenvironment was quantitatively assessed utilizing the CIBERSORT algorithm. Multiple machine learning models and connectivity map analyses were subsequently applied to explore potential biomarkers for PCOS, and nomograms were employed to develop a predictive multigene model of PCOS. Finally, the OSLM status of PCOS and the hub genes expression profiles were preliminarily verified using TUNEL, qRT‒PCR, western blot, and IHC assays in a PCOS mouse model.

RESULTS

19 differential expression genes (DEGs) related to OSLM were identified. Based on 19 DEGs that were strongly influenced by OSLM, PCOS patients were stratified into two distinct clusters, designated Cluster 1 and Cluster 2. Distinct differences in the immune cell proportions existed in normal and two PCOS clusters. The random forest showed the best results, with the least cross-entropy and the utmost AUC (cross-entropy: 0.111 AUC: 0.960). Among the 19 OSLM-related genes, CXCR1, ACP5, CEACAM3, S1PR4, and TCF7 were identified by a Bayesian network and had a good fit with PCOS disease risk by the nomogram (AUC: 0.990 CI: 0.968-1.000). TUNEL assays revealed more severe DNA damage within the ovarian granule cells of PCOS mice than in those of normal mice (P < 0.001). The RNA and protein expression levels of the five hub genes were significantly elevated in PCOS mice, which was consistent with the results of the bioinformatics analyses.

CONCLUSION

A novel predictive model was constructed for PCOS patients and five hub genes were identified as potential biomarkers to offer novel insights into clinical diagnostic strategies for PCOS.

M6A modification and T cells in adipose tissue inflammation

Adipose tissue in the obese state can lead to low-grade chronic inflammation while inducing or exacerbating obesity-related metabolic diseases and impairing overall health.T cells, which are essential immune cells similar to macrophages, are widely distributed in adipose tissue and perform their immunomodulatory function; they also cross-talk with other cells in the vascular stromal fraction. Based on a large number of studies, it has been found that N6 methyl adenine (m6A) is one of the most representative of epigenetic modifications, which affects the crosstalk between T cells, as well as other immune cells, in several ways and plays an important role in the development of adipose tissue inflammation and related metabolic diseases. In this review, we first provide an overview of the widespread presence of T cells in adipose tissue and summarize the key role of T cells in adipose tissue inflammation. Next, we explored the effects of m6A modifications on T cells in adipose tissue from the perspective of adipose tissue inflammation. Finally, we discuss the impact of m6a-regulated crosstalk between T cells and immune cells on the prospects for improving adipose tissue inflammation research, providing additional new ideas for the treatment of obesity.

Aging adipose tissue, insulin resistance, and type 2 diabetes

With the increase of population aging, the prevalence of type 2 diabetes (T2D) is also rising. Aging affects the tissues and organs of the whole body, which is the result of various physiological and pathological processes. Adipose tissue has a high degree of plasticity and changes with aging. Aging changes the distribution of adipose tissue, affects adipogenesis, browning characteristics, inflammatory status and adipokine secretion, and increases lipotoxicity. These age-dependent changes in adipose tissue are an important cause of insulin resistance and T2D. Understanding adipose tissue changes can help promote healthy aging process. This review summarizes changes in adipose tissue ascribable to aging, with a focus on the role of aging adipose tissue in insulin resistance and T2D.

Landscape of unconventional γδ T cell subsets in cancer

T cells are broadly categorized into two groups, namely conventional and unconventional T cells. Conventional T cells are the most prevalent and well-studied subset of T cells. On the other hand, unconventional T cells exhibit diverse functions shared between innate and adaptive immune cells. During recent decades, γδ T cells have received attention for their roles in cancer immunity. These cells can detect various molecules, such as lipids and metabolites. Also, they are known for their distinctive ability to recognize and target cancer cells in the tumor microenvironment (TME). This feature of γδ T cells could provide a unique therapeutic tool to fight against cancer. Understanding the role of γδ T cells in TME is essential to prepare the groundwork to use γδ T cells for clinical purposes. Here, we provide recent knowledge regarding the role γδ T cell subsets in different cancer types.

Mechanisms of γδ T cell accumulation in visceral adipose tissue with aging

γδ T cells are resident in visceral adipose tissue (VAT) where they show an age-associated increase in numbers and contribute to local and systemic chronic inflammation. However, regulation of this population and mechanisms for the age-dependent accumulation are not known. In this study, we identified a progressive trend of γδ T cell accumulation in VAT over the lifespan in mice and explored physiological mechanisms contributing to accumulation. Using isochronic parabiotic pairs of wild-type (WT) and T cell receptor delta knockout (TCRδ KO) mice at young and old age, we confirmed that VAT γδ T cells are predominately a tissue-resident population which is sustained in aging. Migration of peripheral γδ T cells into VAT was observed at less than 10%, with a decreasing trend by aging, suggesting a minor contribution of recruitment to γδ T cell accumulation with aging. Since tissue-resident T cell numbers are tightly regulated by a balance between proliferation and programmed cell death, we further explored these processes. Using in vivo EdU incorporation and the proliferation marker Ki67, we found that the absolute number of proliferating γδ T cells in VAT is significantly higher in the aged compared to young and middle-aged mice, despite a decline in the proportion of proliferating to non-proliferating cells by age. Analysis of apoptosis via caspase 3/7 activation revealed that VAT γδ T cells show reduced apoptosis starting at middle age and continuing into old age. Further, induction of apoptosis using pharmacological inhibitors of Bcl2 family proteins revealed that VAT γδ T cells at middle age are uniquely protected from apoptosis via a mechanism independent of traditional anti-apoptotic Bcl2-family proteins. Collectively, these data indicate that protection from apoptosis at middle age increases survival of tissue-resident γδ T cells resulting in an increased number of proliferative cells from middle age onward, and leading to the age-associated accumulation of γδ T cells in VAT. These findings are important to better understand how adipose tissue dysfunction and related changes in the immune profile contribute to inflammaging among the elderly.

Sex-Related Effect of Aging in Gingival Gamma-Delta T Cells

Aging affects the number and function of gamma-delta (γδ) T cells in a tissue-specific manner, modifying the risk for inflammatory disease. These aging-related γδT-cell variations in gingival tissues that could increase the risk for inflammation and periodontal disease remain unknown. Here we sought to identify quantitative and qualitative variations in gingival γδT cells associated with aging that could have an impact in oral immunoinflammatory responses. For this, gingival tissues from young (4 mo) and aged (24 mo) male and female mice were collected and analyzed by flow cytometry. Cell suspensions were stimulated and stained with eFluor450 (cell viability), anti-CD45 (hematopoietic cells), anti-CD3 (lymphocytes), anti-TCRγδ (γδT cells), anti-IL-15rα (cell proliferation), and anti-Notch-3 (senescence marker). Detection of intracellular cytokines IL-17A and interferon γ (IFNγ) was performed. Gingival expression of specific γ- and δ-chains and cytokines was evaluated by quantitative reverse transcription polymerase chain reaction. A significantly higher number of IL-17A-producing γδT cells and IL-17A expression levels were observed in gingival tissues from aged females but not males. Similarly, the number of gingival Notch-3+ γδT cells increased with aging only in females. IL-15rα was not detected in gingival γδT cells. Chains γ1, 2, 4, 5, 6, and 7 as well as δ1, 2, 4, and 6 were detected. Detection levels of all γ chains except γ1 as well as δ1 and δ2 changed with aging in males, females, or both. Interestingly, number of IL-17A-producing conventional T cells similarly increased with aging only in females. Both sexes showed increased IFNγ+ conventional T-cell numbers with aging; however, it reached significance only in females. In conclusion, the number of gingival IL-17A-producing γδT cells and IL-17A expression increase naturally with aging specifically in females. This sexual dimorphism in gingival γδT and conventional Th17 cell numbers and phenotypes suggests distinct aging-related mechanisms of periodontitis in males and females.

A single-cell atlas of the aging mouse ovary

Ovarian aging leads to diminished fertility, dysregulated endocrine signaling and increased chronic disease burden. These effects begin to emerge long before follicular exhaustion. Female humans experience a sharp decline in fertility around 35 years of age, which corresponds to declines in oocyte quality. Despite a growing body of work, the field lacks a comprehensive cellular map of the transcriptomic changes in the aging mouse ovary to identify early drivers of ovarian decline. To fill this gap we performed single-cell RNA sequencing on ovarian tissue from young (3-month-old) and reproductively aged (9-month-old) mice. Our analysis revealed a doubling of immune cells in the aged ovary, with lymphocyte proportions increasing the most, which was confirmed by flow cytometry. We also found an age-related downregulation of collagenase pathways in stromal fibroblasts, which corresponds to rises in ovarian fibrosis. Follicular cells displayed stress-response, immunogenic and fibrotic signaling pathway inductions with aging. This report provides critical insights into mechanisms responsible for ovarian aging phenotypes. The data can be explored interactively via a Shiny-based web application.

Metaflammation in obesity and its therapeutic targeting

Obesity-associated inflammation is a systemic process that affects all metabolic organs. Prominent among these is adipose tissue, where cells of the innate and adaptive immune system are markedly changed in obesity, implicating these cells in a range of processes linking immune memory to metabolic regulation. Furthermore, weight loss and weight cycling have unexpected effects on adipose tissue immune populations. Here, we review the current literature on the roles of various immune cells in lean and obese adipose tissue. Within this context, we discuss pharmacological and nonpharmacological approaches to obesity treatment and their impact on systemic inflammation.

Lipids and the hallmarks of ageing: From pathology to interventions

Lipids are critical structural and functional architects of cellular homeostasis. Change in systemic lipid profile is a clinical indicator of underlying metabolic pathologies, and emerging evidence is now defining novel roles of lipids in modulating organismal ageing. Characteristic alterations in lipid metabolism correlate with age, and impaired systemic lipid profile can also accelerate the development of ageing phenotype. The present work provides a comprehensive review of the extent of lipids as regulators of the modern hallmarks of ageing viz., cellular senescence, chronic inflammation, gut dysbiosis, telomere attrition, genome instability, proteostasis and autophagy, epigenetic alterations, and stem cells dysfunctions. Current evidence on the modulation of each of these hallmarks has been discussed with emphasis on inherent age-dependent deficiencies in lipid metabolism as well as exogenous lipid changes. There appears to be sufficient evidence to consider impaired lipid metabolism as key driver of the ageing process although much of knowledge is yet fragmented. Considering dietary lipids, the type and quantity of lipids in the diet is a significant, but often overlooked determinant that governs the effects of lipids on ageing. Further research using integrative approaches amidst the known aging hallmarks is highly desirable for understanding the therapeutics of lipids associated with ageing.

1α,25(OH)2D3 ameliorates insulin resistance by alleviating γδ T cell inflammation via enhancing fructose-1,6-bisphosphatase 1 expression

Background: Chronic inflammation caused by immune cells is the central link between obesity and insulin resistance. Targeting the inflammatory process is a highly promising method for reversing systemic insulin resistance. Methods: Blood samples were prospectively collected from 68 patients with type 2 diabetes. C57BL/6J mice were fed either a high-fat diet (HFD) or normal chow (NC). We performed phenotypical and functional analyses of immune cells using flow cytometry. Vitamin D receptor (VDR) knockout γδ T cells were constructed using Cas9-gRNA targeted approaches to identify 1α,25(OH)2D3/VDR signaling pathway-mediated transcriptional regulation of fructose-1,6-bisphosphatase (FBP1) in γδ T cells. Results: Serum vitamin D deficiency aggravates inflammation in circulating γδ T cells in type 2 diabetes patients. We defined a critical role for 1α,25(OH)2D3 in regulating glycolysis metabolism, protecting against inflammation, and alleviating insulin resistance. Mechanistically, 1α,25(OH)2D3-VDR promoted FBP1 expression to suppress glycolysis in γδ T cells, thereby inhibiting Akt/p38 MAPK phosphorylation and reducing inflammatory cytokine production. Notably, therapeutic administration of 1α,25(OH)2D3 restrained inflammation in γδ T cells and ameliorated systemic insulin resistance in obese mice. Conclusions: Collectively, these findings show that 1α,25(OH)2D3 plays an important role in maintaining γδ T cell homeostasis by orchestrating metabolic programs, and is a highly promising target for preventing obesity, inflammation, and insulin resistance.

Aging unconventionally: γδ T cells, iNKT cells, and MAIT cells in aging

Unconventional T cells include γδ T cells, invariant Natural Killer T cells (iNKT) cells and Mucosal Associated Invariant T (MAIT) cells, which are distinguished from conventional T cells by their recognition of non-peptide ligands presented by non-polymorphic antigen presenting molecules and rapid effector functions that are pre-programmed during their development. Here we review current knowledge of the effect of age on unconventional T cells, from early life to old age, in both mice and humans. We then discuss the role of unconventional T cells in age-associated diseases and infections, highlighting the similarities between members of the unconventional T cell family in the context of aging.

Obesity and the risk of cardiometabolic diseases

The prevalence of obesity has reached pandemic proportions, and now approximately 25% of adults in Westernized countries have obesity. Recognized as a major health concern, obesity is associated with multiple comorbidities, particularly cardiometabolic disorders. In this Review, we present obesity as an evolutionarily novel condition, summarize the epidemiological evidence on its detrimental cardiometabolic consequences and discuss the major mechanisms involved in the association between obesity and the risk of cardiometabolic diseases. We also examine the role of potential moderators of this association, with evidence for and against the so-called 'metabolically healthy obesity phenotype', the 'fatness but fitness' paradox or the 'obesity paradox'. Although maintenance of optimal cardiometabolic status should be a primary goal in individuals with obesity, losing body weight and, particularly, excess visceral adiposity seems to be necessary to minimize the risk of cardiometabolic diseases.

Disease progression promotes changes in adipose tissue signatures in type 2 diabetic (db/db) mice: The potential pathophysiological role of batokines

Unlike the white adipose tissue (WAT) which mainly stores excess energy as fat, brown adipose tissue (BAT) has become physiologically important and therapeutically relevant for its prominent role in regulating energy metabolism. The current study makes use of an established animal model of type 2 diabetes (T2D) db/db mice to determine the effect of the disease progression on adipose tissue morphology and gene regulatory signatures. Results showed that WAT and BAT from db/db mice display a hypertrophied phenotype that is consistent with increased expression of the pro-inflammatory cytokine, tumor necrosis factor-alpha (Tnf-α). Moreover, BAT from both db/db and non-diabetic db/+ control mice displayed an age-related impairment in glucose homeostasis, inflammatory profile, and thermogenic regulation, as demonstrated by reduced expression of genes like glucose transporter (Glut-4), adiponectin (AdipoQ), and uncoupling protein 1 (Ucp-1). Importantly, gene expression of the batokines regulating sympathetic neurite outgrowth and vascularization, including bone morphogenic protein 8b (Bmp8b), fibroblast growth factor 21 (Fgf-21), neuregulin 4 (Nrg-4) were altered in BAT from db/db mice. Likewise, gene expression of meteorin-like (Metrnl), growth differentiation factor 15 (Gdt-15), and C-X-C motif chemokine-14 (Cxcl-14) regulating pro- and anti-inflammation were altered. This data provides some new insights into the pathophysiological mechanisms involved in BAT hypertrophy (or whitening) and the disturbances of batokines during the development and progression of T2D. However, these are only preliminary results as additional experiments are necessary to confirm these findings in other experimental models of T2D.

Adipose tissue aging is regulated by an altered immune system

Adipose tissue is a widely distributed organ that plays a critical role in age-related physiological dysfunctions as an important source of chronic sterile low-grade inflammation. Adipose tissue undergoes diverse changes during aging, including fat depot redistribution, brown and beige fat decrease, functional decline of adipose progenitor and stem cells, senescent cell accumulation, and immune cell dysregulation. Specifically, inflammaging is common in aged adipose tissue. Adipose tissue inflammaging reduces adipose plasticity and pathologically contributes to adipocyte hypertrophy, fibrosis, and ultimately, adipose tissue dysfunction. Adipose tissue inflammaging also contributes to age-related diseases, such as diabetes, cardiovascular disease and cancer. There is an increased infiltration of immune cells into adipose tissue, and these infiltrating immune cells secrete proinflammatory cytokines and chemokines. Several important molecular and signaling pathways mediate the process, including JAK/STAT, NFκB and JNK, etc. The roles of immune cells in aging adipose tissue are complex, and the underlying mechanisms remain largely unclear. In this review, we summarize the consequences and causes of inflammaging in adipose tissue. We further outline the cellular/molecular mechanisms of adipose tissue inflammaging and propose potential therapeutic targets to alleviate age-related problems.