Adapting to obesity with adipose tissue inflammation

Regulatory T cells differentiation in visceral adipose tissues contributes to insulin resistance by regulating JAZF-1/PPAR-γ pathway

Regulatory T cell (Treg) activity and differentiation in visceral adipose tissue (VAT) play an important role in inhibiting chronic inflammation and insulin resistance. Whether JAZF-1 and PPAR-γ mediate VAT Treg differentiation to promote the inhibition of chronic inflammation and insulin resistance remains unclear. Here, we investigated the roles of JAZF-1 and PPAR-γ in VAT Treg differentiation, inflammation and insulin resistance using a transgenic mouse model. First, we determined that the levels of glucose and insulin biochemical markers in the JAZF-1 transgenic general feeding or high-fat groups were lower than those in the wild-type general feeding or high-fat groups. Second, the levels of CD4⁺ , CD25⁺ , and FOXP3⁺ differentiation markers in the JAZF-1 transgenic general feeding or high-fat groups were significantly higher than those in the wild-type groups. PPAR-γ inhibition was associated with low levels of CD4⁺ , CD25⁺ and FOXP3⁺ differentiation markers. Third, the levels of TNF-α, IL-1β and IL-6 in the JAZF-1 transgenic groups were lower than those in the wild-type groups, whereas IL-10 and TGF-β levels were higher in the JAZF-1 transgenic groups than in the wild-type groups. After using the PPAR-γ inhibitor, we observed that TNF-α, IL-1β and IL-6 increased, while IL-10 and TGF-β decreased. We found that JAZF-1 and PPAR-γ could promote Tregs differentiation and regulate insulin resistance by synergistically decreasing the expression levels of TNF-α, IL-1β and IL-6 and increasing those of IL-10 and TGF-β.

Epigenome-wide meta-analysis of BMI in nine cohorts: Examining the utility of epigenetically predicted BMI

This study sought to examine the association between DNA methylation and body mass index (BMI) and the potential of BMI-associated cytosine-phosphate-guanine (CpG) sites to provide information about metabolic health. We pooled summary statistics from six trans-ethnic epigenome-wide association studies (EWASs) of BMI representing nine cohorts (n = 17,034), replicated these findings in the Women's Health Initiative (WHI, n = 4,822), and developed an epigenetic prediction score of BMI. In the pooled EWASs, 1,265 CpG sites were associated with BMI (p < 1E-7) and 1,238 replicated in the WHI (FDR < 0.05). We performed several stratified analyses to examine whether these associations differed between individuals of European and African descent, as defined by self-reported race/ethnicity. We found that five CpG sites had a significant interaction with BMI by race/ethnicity. To examine the utility of the significant CpG sites in predicting BMI, we used elastic net regression to predict log-normalized BMI in the WHI (80% training/20% testing). This model found that 397 sites could explain 32% of the variance in BMI in the WHI test set. Individuals whose methylome-predicted BMI overestimated their BMI (high epigenetic BMI) had significantly higher glucose and triglycerides and lower HDL cholesterol and LDL cholesterol compared to accurately predicted BMI. Individuals whose methylome-predicted BMI underestimated their BMI (low epigenetic BMI) had significantly higher HDL cholesterol and lower glucose and triglycerides. This study confirmed 553 and identified 685 CpG sites associated with BMI. Participants with high epigenetic BMI had poorer metabolic health, suggesting that the overestimation may be driven in part by cardiometabolic derangements characteristic of metabolic syndrome.

RIIβ-PKA in GABAergic Neurons of Dorsal Median Hypothalamus Governs White Adipose Browning

The RIIβ subunit of  cAMP-dependent protein kinase A (PKA) is expressed in the brain and adipose tissue. RIIβ-knockout mice show leanness and increased UCP1 in brown adipose tissue. The authors have previously reported that RIIβ reexpression in hypothalamic GABAergic neurons rescues the leanness. However, whether white adipose tissue (WAT) browning contributes to the leanness and whether RIIβ-PKA in these neurons governs WAT browning are unknown. Here, this work reports that RIIβ-KO mice exhibit a robust WAT browning. RIIβ reexpression in dorsal median hypothalamic GABAergic neurons (DMH GABAergic neurons) abrogates WAT browning. Single-cell sequencing, transcriptome sequencing, and electrophysiological studies show increased GABAergic activity in DMH GABAergic neurons of RIIβ-KO mice. Activation of DMH GABAergic neurons or inhibition of PKA in these neurons elicits WAT browning and thus lowers body weight. These findings reveal that RIIβ-PKA in DMH GABAergic neurons regulates WAT browning. Targeting RIIβ-PKA in DMH GABAergic neurons may offer a clinically useful way to promote WAT browning for treating obesity and other metabolic disorders.

NLRP3-mediated inflammation in cardio-oncology: sterile yet harmful

Despite significant advances and the continuous development of novel, effective therapies to treat a variety of malignancies, cancer therapy-induced cardiotoxicity has been identified as a prominent cause of morbidity and mortality, closely competing with secondary malignancies. This unfortunate limitation has prompted the inception of the field of cardio-oncology with its purpose to provide the necessary knowledge and key information on mechanisms that support the use of the most efficacious cancer therapy with minimal or no interruption while paying close attention to preventing cardiovascular related morbidity and mortality. Several mechanisms that contribute to cancer therapy-induced cardiotoxicity have been proposed and studied. These mainly involve mitochondrial dysfunction and reactive oxygen species-induced oxidative stress, lysosomal damage, impaired autophagy, cell senescence, DNA damage, and sterile inflammation with the formation and activation of the NLRP3 inflammasome. In this review, we focus on describing the principal mechanisms for different classes of cancer therapies that lead to cardiotoxicity involving the NLRP3 inflammasome. We also summarize current evidence of cardio-protection with inflammasome inhibitors in the context of heart disease in general, and further highlight the potential application of this evidence for clinical translation in at risk patients for the purpose of preventing cancer therapy associated cardiovascular morbidity and mortality.

RELATIONSHIP BETWEEN SELENIUM NUTRITIONAL STATUS AND MARKERS OF LOW-GRADE CHRONIC INFLAMMATION IN OBESE WOMEN

Low-grade chronic inflammation is one of the main disorders that characterize adipose tissue dysfunction in obesity and is an important element in the pathogenesis of several comorbidities. In this context, selenium is an essential micronutrient that exerts important anti-inflammatory functions, and the role of selenium in controlling inflammation associated with obesity is not well defined. Thus, this study aimed to evaluate the relationship between markers of the nutritional status of selenium and low-grade chronic inflammation in obese women. This cross-sectional study included 81 women aged between 18 and 50 years, who were divided into two groups according to body mass index (BMI): the obesity group (n = 38) and normal weight group (n = 43). Selenium intake was assessed by 3-day diet records. The plasma, erythrocyte, and urinary selenium concentrations were determined using inductively coupled plasma optical emission spectrometry. The analysis of serum cytokines interleukin (IL)-8, IL-1β, IL-6, IL-10, and tumor necrosis factor alpha (TNFα) was performed using flow cytometry. The results of this study revealed that the obese women had higher dietary intake of selenium than eutrophic women. However, obese participants showed decreased selenium concentrations in plasma and erythrocytes, in parallel with increased concentrations of selenium in the urine. Regarding the inflammatory parameters, obese women exhibited higher concentrations of IL-6 and lower concentrations of the cytokines IL-8, IL-1β, and TNFα than eutrophic women. In the binary logistic regression analysis, erythrocyte selenium was considered an independent predictor of the serum concentrations of cytokine IL-8 in obese women, reflecting the anti-inflammatory action of this micronutrient.

Adipose-specific deletion of the cation channel TRPM7 inhibits TAK1 kinase-dependent inflammation and obesity in male mice

Chronic inflammation of white adipose tissue is a key link between obesity and the associated metabolic syndrome. Transient receptor potential melastatin-like 7 (TRPM7) is known to be related to inflammation; however, the role of TRPM7 in adipocyte phenotype and function in obesity remains unclear. Here, we observe that the activation of adipocyte TRPM7 plays an essential role in pro-inflammatory responses. Adult male mice are used in our experiments. Adipocyte-specific deficiency in TRPM7 attenuates the pro-inflammatory phenotype, improves glucose homeostasis, and suppresses weight gain in mice fed a high-fat diet. Mechanistically, the pro-inflammatory effect of TRPM7 is dependent on Ca²⁺ signaling. Ca²⁺ influx initiated by TRPM7 enhances transforming growth factor-β activated kinase 1 activation via the co-regulation of calcium/calmodulin-dependent protein kinase II and tumor necrosis factor receptor-associated factor 6, leading to exacerbated nuclear factor kappa B signaling. Additionally, obese mice treated with TRPM7 inhibitor are protected against obesity and insulin resistance. Our results demonstrate TRPM7 as a factor in the development of adipose inflammation that regulates insulin sensitivity in obesity.

Extracellular Matrix (ECM) and Fibrosis in Adipose Tissue: Overview and Perspectives

Fibrosis in adipose tissue is a major driver of obesity-related metabolic dysregulation. It is characterized by an overaccumulation of extracellular matrix (ECM) during unhealthy expansion of adipose tissue in response to over nutrition. In obese adipose-depots, hypoxia stimulates multiple pro-fibrotic signaling pathways in different cell populations, thereby inducing the overproduction of the ECM components, including collagens, noncollagenous proteins, and additional enzymatic components of ECM synthesis. As a consequence, local fibrosis develops. The result of fibrosis-induced mechanical stress not only triggers cell necrosis and inflammation locally in adipose tissue but also leads to system-wide lipotoxicity and insulin resistance. A better understanding of the mechanisms underlying the obesity-induced fibrosis will help design therapeutic approaches to reduce or reverse the pathological changes associated with obese adipose tissue. Here, we aim to summarize the major advances in the field, which include newly identified fibrotic factors, cell populations that contribute to the fibrosis in adipose tissue, as well as novel mechanisms underlying the development of fibrosis. We further discuss the potential therapeutic strategies to target fibrosis in adipose tissue for the treatment of obesity-linked metabolic diseases and cancer. © 2023 American Physiological Society. Compr Physiol 13:4387-4407, 2023.

Dietary phytochemical and metabolic disease prevention: Focus on plant proteins

Plant-based functional foods have attracted increasing research interest to validate their use in preventing metabolic disease. Since it is increasingly recognized that inflammation, oxidative stress, and circadian rhythm play vital roles in various metabolic diseases, including diabetes, obesity and non-alcoholic liver disease, plant proteins, protein hydrolysates, and food extracts that intervene in these biological processes are promising dietary supplements to prevent metabolic diseases. Here, we reviewed the recent research on plant-based foods used for metabolic disease prevention and provided new perspectives regarding the current study gaps and future directions in this field.

Adipose Tissue Remodeling in Pathophysiology

Rather than serving as a mere onlooker, adipose tissue is a complex endocrine organ and active participant in disease initiation and progression. Disruptions of biological processes operating within adipose can disturb healthy systemic physiology, the sequelae of which include metabolic disorders such as obesity and type 2 diabetes. A burgeoning interest in the field of adipose research has allowed for the elucidation of regulatory networks underlying both adipose tissue function and dysfunction. Despite this progress, few diseases are treated by targeting maladaptation in the adipose, an oft-overlooked organ. In this review, we elaborate on the distinct subtypes of adipocytes, their developmental origins and secretory roles, and the dynamic interplay at work within the tissue itself. Central to this discussion is the relationship between adipose and disease states, including obesity, cachexia, and infectious diseases, as we aim to leverage our wealth of knowledge for the development of novel and targeted therapeutics.

The Role of Maternal Vitamin D Deficiency in Offspring Obesity: A Narrative Review

Currently, vitamin D (VD) deficiency during pregnancy is widespread globally, causing unfavorable pregnancy outcomes for both mothers and infants for a longer time than expected, based on the Developmental Origins of Health and Disease (DOHaD) theory. As VD plays a key role in maintaining normal glucose and lipid metabolism, maternal VD deficiency may lead to obesity and other obesity-related diseases among offspring later in life. This review mainly focuses on the effect of maternal VD deficiency on offspring lipid metabolism, reviewing previous clinical and animal studies to determine the effects of maternal VD deficit on offspring obesity and potential mechanisms involved in the progression of offspring obesity. Emerging clinical evidence shows that a low VD level may lead to abnormal growth (either growth restriction or largeness for gestational age) and lipid and glucose metabolism disorders in offspring. Here, we also outline the link between maternal VD deficiency and life-long offspring effects, including the disorder of adipogenesis, the secretion of adipocytokines (including leptin, resistin, and adiponectin), activated systemic inflammation, increased oxidative reactions in adipose tissue, insulin resistance, and abnormal intestinal gut microbiota. Thus, there is an urgent need to take active steps to address maternal VD deficiency to relieve the global burden of obesity.

Metabolic effects of CCL5 deficiency in lean and obese mice

Accumulation and activation of immunocytes in adipose tissues are essential to obesity-induced inflammation and insulin resistance. Chemokines are pivotal for the recruitment of immunocytes in adipose tissue during obesity. Chemokine (C-C motif) ligand 5 (CCL5) plays a vital role in the recruitment of immunocytes to sites of inflammation. CCL5 expression level is increased in obese adipose tissue from humans and mice. However, the role of CCL5 in obesity-induced adipose inflammation remains unclear. Our study found that the CCL5 expression level was increased in the epididymal white adipose tissue (eWAT) of obese mice, particularly in CD8⁺ T cells. CCL5 knockout (KO) mice exhibited better glucose tolerance than wild-type (WT) mice under lean conditions. In contrast, CCL5 KO mice were more insulin resistant and had severe hepatic steatosis than WT mice under obese conditions. Increased T cells in adipose tissue heaven adipose inflammation in obese CCL5 KO mice. The compensatory increased T cell-associated chemokines may account for increased T cell content in the eWAT of obese CCL5 KO mice. These findings imply that CCL5 deficiency exacerbates adipose inflammation and impairs insulin sensitivity in the metabolic tissues of obese mice.

Telomere length dynamics measured by flow-FISH in patients with obesity undergoing bariatric surgery

Obesity has negative effects on comorbidities, health-related quality of life and survival. Telomere length (TL) changes after bariatric surgery have been reported, but the studies are contradictory, and analyses using state-of-the art techniques for TL measurement, such as flow-FISH, are sparse. We measured TL dynamics via flow-FISH in patients undergoing bariatric surgery and compared their TL with 105 healthy individuals. Patients with obesity who underwent bariatric surgery were included. Lymphocyte and granulocyte absolute and age-adjusted (aa) TL were analyzed by flow-FISH before (preoperative cohort, n = 45) and after surgery (follow-up cohort, n = 35) at month 5.5 ± 3.9 (mean ± standard deviation [SD]). The initial lymphocyte aaTL was significantly shorter (-0.37 kb ± 0.18 kb, P = 0.045) in patients with obesity, while the granulocyte aaTL was not different from that in the healthy comparison population (0.28 kb ± 0.17 kb, P = 0.11). The telomere dynamics after surgery showed an increase in mean TL in both lymphocytes and granulocytes of patients with a pronounced BMI loss of ≥ 10 kg/m². We did not find any association between TL increase after surgery and age, sex or the type of procedure selected for bariatric surgery. We confirmed that patients suffering from obesity have significantly shorter lymphocyte TL using flow-FISH. Along with and dependent on the degree of weight reduction after bariatric surgery, TL significantly increased in both lymphocytes and granulocytes after a mean of 5.5 months. Our results show that bariatric surgery affects not only body weight but also biomarkers of aging, such as TL.

Separate and combined effects of advanced age and obesity on mammary adipose inflammation, immunosuppression and tumor progression in mouse models of triple negative breast cancer

Introduction

Advanced age and obesity are independent risk and progression factors for triple negative breast cancer (TNBC), which presents significant public health concerns for the aging population and its increasing burden of obesity. Due to parallels between advanced age- and obesityrelated biology, particularly adipose inflammation, we hypothesized that advanced age and obesity each accelerate mammary tumor growth through convergent, and likely interactive, mechanisms.

Methods

To test this hypothesis, we orthotopically transplanted murine syngeneic TNBC cells into the mammary glands of young normoweight control (7 months), young diet-induced obese (DIO), aged normoweight control (17 months), and aged DIO female C57BL/6J mice.

Results

Here we report accelerated tumor growth in aged control and young DIO mice, compared with young controls. Transcriptional analyses revealed, with a few exceptions, overlapping patterns of mammary tumor inflammation and tumor immunosuppression in aged control mice and young DIO mice, relative to young controls. Moreover, aged control and young DIO tumors, compared with young controls, had reduced abundance ofcytotoxic CD8 T cells. Finally, DIO in advanced age exacerbated mammary tumor growth, inflammation and tumor immunosuppression.

Discussion

These findings demonstrate commonalities in the mechanisms driving TNBC in aged and obese mice, relative to young normoweight controls. Moreover, we found that advanced age and DIO interact to accelerate mammary tumor progression. Given the US population is getting older and more obese, age- and obesity-related biological differences will need to be considered when developing mechanism-based strategies for preventing or controlling breast cancer.

Profiling mouse brown and white adipocytes to identify metabolically relevant small ORFs and functional microproteins

Microproteins (MPs) are a potentially rich source of uncharacterized metabolic regulators. Here, we use ribosome profiling (Ribo-seq) to curate 3,877 unannotated MP-encoding small ORFs (smORFs) in primary brown, white, and beige mouse adipocytes. Of these, we validated 85 MPs by proteomics, including 33 circulating MPs in mouse plasma. Analyses of MP-encoding mRNAs under different physiological conditions (high-fat diet) revealed that numerous MPs are regulated in adipose tissue in vivo and are co-expressed with established metabolic genes. Furthermore, Ribo-seq provided evidence for the translation of Gm8773, which encodes a secreted MP that is homologous to human and chicken FAM237B. Gm8773 is highly expressed in the arcuate nucleus of the hypothalamus, and intracerebroventricular administration of recombinant mFAM237B showed orexigenic activity in obese mice. Together, these data highlight the value of this adipocyte MP database in identifying MPs with roles in fundamental metabolic and physiological processes such as feeding.

FSTL3 is highly expressed in adipose tissue of individuals with overweight or obesity and is associated with inflammation

OBJECTIVE

This study aimed to investigate the expression of follistatin-like 3 (FSTL3) in adipose tissue in individuals with overweight or obesity and to explore the role of FSTL3 in human adipocytes, as well as the relationship between serum FSTL3 levels and fat distribution and inflammation.

METHODS

This study enrolled 236 individuals (171 with overweight or obesity; aged 18-67 years). Bulk transcriptome sequencing was performed on subcutaneous and visceral adipose tissue. The function of FSTL3 was studied in human adipocytes. Serum FSTL3 levels were measured using enzyme-linked immunosorbent assay.

RESULTS

Adipose FTSL3 expression was higher in individuals with overweight or obesity than in individuals with normal weight. FSTL3 was mainly expressed in mature adipocytes and stimulated by tumor necrosis factor alpha (TNFα). FSTL3 suppressed inflammatory responses in human adipocytes, whereas FSTL3 knockdown promoted inflammatory responses. Serum FSTL3 levels were correlated with adipose FTSL3 expression and obesity-related indicators (all p < 0.05). Multiple linear regression analysis showed that serum FSTL3 levels were independently associated with the visceral fat area and serum TNFα levels (both p < 0.05).

CONCLUSIONS

FSTL3 was highly expressed in adipose tissue in individuals with overweight or obesity and could suppress adipocyte inflammation. Serum FSTL3 levels might be considered as a biomarker of visceral obesity and inflammation.

Inulin increases the beneficial effects of rhubarb supplementation on high-fat high-sugar diet-induced metabolic disorders in mice: impact on energy expenditure, brown adipose tissue activity, and microbiota

Consumption of prebiotics and plant-based compounds have many beneficial health effects through modulation of gut microbiota composition and are considered as promising nutritional strategy for the treatment of metabolic diseases. In the present study, we assessed the separated and combined effects of inulin and rhubarb on diet-induced metabolic disease in mice. We showed that supplementation with both inulin and rhubarb abolished the total body and fat mass gain upon high-fat and high-sucrose diet (HFHS) as well as several obesity-associated metabolic disorders. These effects were associated with increased energy expenditure, lower whitening of the brown adipose tissue, higher mitochondria activity and increased expression of lipolytic markers in white adipose tissue. Despite modifications of intestinal gut microbiota and bile acid compositions by inulin or rhubarb alone, combination of both inulin and rhubarb had minor additional impact on these parameters. However, the combination of inulin and rhubarb increased the expression of several antimicrobial peptides and higher goblet cell numbers, thereby suggesting a reinforcement of the gut barrier. Together, these results suggest that the combination of inulin and rhubarb in mice potentiates beneficial effects of separated rhubarb and inulin on HFHS-related metabolic disease and could be considered as nutritional strategy for the prevention and treatment of obesity and related pathologies.

Two-sided roles of adipose tissue: Rethinking the obesity paradox in various human diseases from a new perspective

Overweight and obesity, as a result of excess fat accumulation, have become a worldwide public health issue. Recent studies have shown that obesity is closely related to many human diseases, such as cancer, cardiovascular diseases, and type 2 diabetes mellitus, in which adipose tissue plays a dual role. In addition to thermal and mechanical insulation and a critical role in energy storage and heat production, adipose tissue is also a highly plastic endocrine and signaling organ that secretes multiple bioactive molecules for inter-organ crosstalk. The phenotypic and biological changes of adipose tissue under pathological conditions, especially in obesity, increase the challenge of deciphering the positive or negative effects of adipose tissue in disease. Despite numerous studies on obesity and adipose tissue, the ambiguous role of adipose tissue on specific organs or tissues in different diseases is not fully understood, and the definite mechanisms remain obscure. In this review, we first summarize the basic biological characteristics of adipose tissue in the physiological state and the abnormal remodeling of adipose tissue during obesity. We then discuss the complex and disparate effects of obesity on various human diseases, with a particular focus on the dual roles and underlying mechanisms of adipose tissue, a quintessential player in obesity, in this process. More importantly, rethinking the causes of the "obesity paradox" phenomenon in diseases from the perspective of adipose homeostasis and dysfunction provides a novel strategy for disease treatment by intervening in fat function.

Obesity and renal disease: Benefits of bariatric surgery

The prevalence of obesity, a preventable and reversible condition with a high impact on health, continues to rise, especially after the COVID-19 pandemic. Severe overweight is well recognized as a risk factor for diabetes and hypertension, among other conditions, that may increase cardiovascular risk. Obesity has grown simultaneously with a rise in the prevalence of chronic kidney disease, and a pathophysiological link has been established, which explains its role in generating the conditions to facilitate the emergence and maximize the impact of the risk factors of chronic kidney disease and its progression to more advanced stages. Knowing the mechanisms involved and having different tools to reverse the overweight and its consequences, bariatric surgery has arisen as a useful and efficient method, complementary or alternative to others, such as lifestyle changes and/or pharmacotherapy. In a detailed review, the mechanisms involved in the renal consequences of obesity, the impact on risk factors, and the potential benefit of bariatric surgery at different stages of the disease and its progression are exposed and analyzed. Although the observational evidence supports the value of bariatric surgery as a renoprotective measure in individuals with obesity, diabetic or not, randomized studies are expected to establish evidence-based recommendations that demonstrate its positive risk-benefit balance as a complementary or alternative therapeutic tool.

ER stress and inflammation crosstalk in obesity

The endoplasmic reticulum (ER) governs the proper folding of polypeptides and proteins through various chaperones and enzymes residing within the ER organelle. Perturbation in the ER folding process ensues when overwhelmed protein folding exceeds the ER handling capacity, leading to the accumulation of misfolded/unfolded proteins in the ER lumen-a state being referred to as ER stress. In turn, ER stress induces a gamut of signaling cascades, termed as the "unfolded protein response" (UPR) that reinstates the ER homeostasis through a panel of gene expression modulation. This type of UPR is usually deemed "adaptive UPR." However, persistent or unresolved ER stress hyperactivates UPR response, which ultimately, triggers cell death and inflammatory pathways, termed as "maladaptive/terminal UPR." A plethora of evidence indicates that crosstalks between ER stress (maladaptive UPR) and inflammation precipitate obesity pathogenesis. In this regard, the acquisition of the mechanisms linking ER stress to inflammation in obesity might unveil potential remedies to tackle this pathological condition. Herein, we aim to elucidate key mechanisms of ER stress-induced inflammation in the context of obesity and summarize potential therapeutic strategies in the management of obesity through maneuvering ER stress and ER stress-associated inflammation.

The Prevalence and Agreement of Sarcopenic Obesity Using Different Definitions and Its Association with Mild Cognitive Impairment

BACKGROUND

The consistent definition of sarcopenic obesity (SO) is limited, its association with mild cognitive impairment (MCI) has not been clarified.

OBJECTIVE

This study aimed to evaluate the prevalence and agreement of SO using different definitions and the association between SO and MCI.

METHODS

SO was diagnosed by the co-existence of sarcopenia defined by the Asia Working Group for Sarcopenia (AWGS) and obesity by body mass index (BMI), visceral fat area (VFA), waist circumference (WC), or body fat percentage (BF%). Cohen's kappa was used to assess the agreement between the different definitions. The association between SO and MCI was assessed using multivariable logistic regression.

RESULTS

Among 2,451 participants, the prevalence of SO ranged from 1.7% to 8.0% under different definitions. SO defined by AWGS and BMI (AWGS+BMI) showed fair agreements with the other three criteria (κ ranged from 0.334 to 0.359). The other criteria showed good agreements with each other. The κ statistics were 0.882 for AWGS+VFA and AWGS+BF%, 0.852 for AWGS+VFA and AWGS+WC, and 0.804 for AWGS+BF% and AWGS+WC, respectively. When using different diagnoses of SO, compared with the health group, the adjusted ORs of MCI for SO were 1.96 (95% CI: 1.29-2.99, SO: AWGS+WC), 1.75 (95% CI: 1.14-2.68, SO: AWGS+VFA), 1.94 (95% CI: 1.29-2.93, SO: AWGS+BF%), and 1.45 (95% CI: 0.67-3.12, SO: AWGS+BMI), respectively.

CONCLUSION

Using different obesity indicators combined with AWGS to diagnose SO, BMI had lower prevalence and agreement compared with other three indicators. SO was associated with MCI under different methods (WC, VFA, or BF%).

Fat and not sugar as the determining factor for gut microbiota changes, obesity, and related metabolic disorders in mice

Diet-induced obesity contributes to the development of type 2 diabetes, insulin resistance, metabolic inflammation, oxidative and endoplasmic reticulum (ER) stress. Overall, obesity is associated with deviations in the composition and functionality of the gut microbiota. There are many divergent findings regarding the link between the excessive intake of certain dietary components (i.e., fat and sugar) and obesity development. We therefore investigated the effect of specific diets, with a different content of sugar and fat, in promoting obesity and related comorbidities as well as their impact on microbial load and gut microbiota composition/diversity. C57BL/6J mice were fed either a low-sugar, low-fat control diet (CT), a high-sugar diet (HS), a high-fat, high-sugar diet (HF/HS), or a high-fat diet (HF) for 8 wk. The impact of the different diets on obesity, glucose metabolism, inflammation, and oxidative and ER stress was determined. Diet-induced changes in the gut microbiota composition and density were also analyzed. HF diet-fed mice showed the highest body weight and fat mass gains and displayed the most impaired glucose and insulin profiles. HS, HF/HS, and HF diets differently affected hepatic cholesterol content and mRNA expression of several markers associated with immune cells, inflammation, oxidative and ER stress in several organs/tissues. In addition, HF diet feeding resulted in a decreased microbial load at the end of the experiment. When analyzing the gut microbiota composition, we found that HS, HF/HS, and HF diets induced specific changes in the abundance of certain bacterial taxa. This was not associated with a specific change in systemic inflammatory markers, but HS mice exhibited higher FGF21 plasma levels compared with HF diet-fed mice. Taken together, our results highlight that dietary intake of different macronutrients distinctively impacts the development of an obese/diabetic state and the regulation of metabolic inflammation in specific organs. We propose that these differences are not only obesity-driven but that changes in the gut microbiota composition may play a key role in this context.NEW & NOTEWORTHY To our knowledge, this study is the first to demonstrate that dietary macronutrients (i.e., sugar and fat) have an impact on fecal bacterial cell counting and quantitative microbiome profiling in mice. Yet, we demonstrate that dietary fat is the determining factor to promote obesity and diabetes progression, and local inflammation in different body sites. These observations can help to disentangle the conundrum of the detrimental effects of fat and sugar in our dietary habits.

Essential Minerals and Metabolic Adaptation of Immune Cells

Modern lifestyles deviated considerably from the ancestral routines towards major shifts in diets and increased sedentarism. The trace elements status of the human body is no longer adequately supported by micronutrient-inferior farmed meats and crop commodities produced by the existing agricultural food systems. This is particular evident in the increased obesogenic adipogenesis and low-grade inflammation that fails to resolve with time. The metabolically restrictive environment of the inflamed tissues drives activation and proliferation of transient and resident populations of immune cells in favor of pro-inflammatory phenotypes, as well as a part of the enhanced autoimmune response. As different stages of the immune activation and resolution depend on the availability of specific minerals to maintain the structural integrity of skin and mucus membranes, activation and migration of immune cells, activation of the complement system, and the release of pro-inflammatory cytokines and chemokines, this review discusses recent advances in our understanding of the contribution of select minerals in optimizing the responses of innate and adaptive immune outcomes. An abbreviated view on the absorption, transport, and delivery of minerals to the body tissues as related to metabolic adaptation is considered.

Obese visceral fat tissue inflammation: from protective to detrimental?

Obesity usually is accompanied by inflammation of fat tissue, with a prominent role of visceral fat. Chronic inflammation in obese fat tissue is of a lower grade than acute immune activation for clearing the tissue from an infectious agent. It is the loss of adipocyte metabolic homeostasis that causes activation of resident immune cells for supporting tissue functions and regaining homeostasis. Initially, the excess influx of lipids and glucose in the context of overnutrition is met by adipocyte growth and proliferation. Eventual lipid overload of hypertrophic adipocytes leads to endoplasmic reticulum stress and the secretion of a variety of signals causing increased sympathetic tone, lipolysis by adipocytes, lipid uptake by macrophages, matrix remodeling, angiogenesis, and immune cell activation. Pro-inflammatory signaling of adipocytes causes the resident immune system to release increased amounts of pro-inflammatory and other mediators resulting in enhanced tissue-protective responses. With chronic overnutrition, these protective actions are insufficient, and death of adipocytes as well as senescence of several tissue cell types is seen. This structural damage causes the expression or release of immunostimulatory cell components resulting in influx and activation of monocytes and many other immune cell types, with a contribution of stromal cells. Matrix remodeling and angiogenesis is further intensified as well as possibly detrimental fibrosis. The accumulation of senescent cells also may be detrimental via eventual spread of senescence state from affected to neighboring cells by the release of microRNA-containing vesicles. Obese visceral fat inflammation can be viewed as an initially protective response in order to cope with excess ambient nutrients and restore tissue homeostasis but may contribute to tissue damage at a later stage.

Deletion of the Alzheimer's disease risk gene Abi3 locus results in obesity and systemic metabolic disruption in mice

Alzheimer's disease (AD) genetics studies have identified a coding variant within ABI3 gene that increases the risk of developing AD. Recently, we demonstrated that deletion of the Abi3 gene locus dramatically exacerbates AD neuropathology in a transgenic mouse model of amyloidosis. In the course of this AD project, we unexpectedly found that deletion of the Abi3 gene locus resulted in a dramatic obese phenotype in non-transgenic mice. Here, we report our investigation into this serendipitous metabolic finding. Specifically, we demonstrate that mice with deletion of the Abi3 gene locus (Abi3-/- ) have dramatically increased body weight and body fat. Further, we determined that Abi3-/- mice have impaired energy expenditure. Additionally, we found that deletion of the Abi3 gene locus altered gene expression within the hypothalamus, particularly within immune-related pathways. Subsequent immunohistological analysis of the central nervous system (CNS) revealed that microglia number and area were decreased specifically within the mediobasal hypothalamus of Abi3-/- mice. Altogether, this investigation establishes the functional importance of the Abi3 gene locus in the regulation of systemic metabolism and maintenance of healthy body weight. While our previous findings indicated the importance of Abi3 in neurodegeneration, this study indicates that Abi3 related functions are also essential for metabolic regulation.

Effect and Correlation of Rosa roxburghii Tratt Fruit Vinegar on Obesity, Dyslipidemia and Intestinal Microbiota Disorder in High-Fat Diet Mice

To investigate the effect of Rosa roxburghii Tratt fruit vinegar (RFV) on the intervention of obesity and hyperlipidemia and its potential mechanism, a high-fat diet (HFD)-induced obesity model in mice was established and gavaged with RFV, saline and xuezhikang for 30 consecutive days, respectively. The results showed that RFV supplementation significantly reduced fat accumulation, and improved dyslipidemia and liver inflammation in HFD mice. RFV intervention for 30 days significantly improved the diversity of gut microbiota and altered the structure of gut microbiota in HFD mice. Compared with the model group (MC), the ratio of Firmicutes to Bacteroidetes at least decreased by 15.75% after RFV treatment, and increased the relative abundance of beneficial bacteria (Proteobacteria, Bacteroidetes, Lactobacillaceae, Bacteroides, Akkermansia,) and decreased the relative abundance of harmful bacteria (Ruminococcaceae, Erysipelotrichaceae, Ruminococcaceae _UCG-013, Lachnospiraceae, Allobaculum, Actinobacteria). Spearman’s correlation analysis revealed that Erysipelotrichaceae, Allobaculum, Lachnospiraceae, Ruminococcaceae, Ruminococcaceae_UCG-013, uncultured_bacterium_f_Lachnospiraceae and Desulfobacterota were positively correlated (p < 0.05) with the body weight of mice, while Proteobacteria was negatively correlated (p < 0.05) with the body weight of mice. The two main bacteria that could promote dyslipidemia in obese mice were Actinobacteria and Firmicutes, while those that played a mitigating role were mainly Bacteroidetes. It is concluded that RFV plays an important role in the intervention of obesity and related complications in HFD mice by regulating their gut microbiota.

Maternal Western-style diet remodels the transcriptional landscape of fetal hematopoietic stem and progenitor cells in rhesus macaques

Maternal obesity adversely impacts the in utero metabolic environment, but its effect on fetal hematopoiesis remains incompletely understood. During late development, the fetal bone marrow (FBM) becomes the major site where macrophages and B lymphocytes are produced via differentiation of hematopoietic stem and progenitor cells (HSPCs). Here, we analyzed the transcriptional landscape of FBM HSPCs at single-cell resolution in fetal macaques exposed to a maternal high-fat Western-style diet (WSD) or a low-fat control diet. We demonstrate that maternal WSD induces a proinflammatory response in FBM HSPCs and fetal macrophages. In addition, maternal WSD consumption suppresses the expression of B cell development genes and decreases the frequency of FBM B cells. Finally, maternal WSD leads to poor engraftment of fetal HSPCs in nonlethally irradiated immunodeficient NOD/SCID/IL2rγ^-/- mice. Collectively, these data demonstrate for the first time that maternal WSD impairs fetal HSPC differentiation and function in a translationally relevant nonhuman primate model.

miR-379 mediates insulin resistance and obesity through impaired angiogenesis and adipogenesis regulated by ER stress

We investigated the role of microRNA (miR-379) in the pathogenesis of obesity, adipose tissue dysfunction, and insulin resistance (IR). We used miR-379 knockout (miR-379KO) mice to test whether loss of miR-379 affects high-fat diet (HFD)-induced obesity and IR via dysregulation of key miR-379 targets in adipose tissue. Increases in body weight, hyperinsulinemia, and IR in wild-type (WT)-HFD mice were significantly attenuated in miR-379KO-HFD mice with some sex differences. Relative to control chow-fed mice, in WT-HFD mice, expression of miR-379 and C/EBP homologous protein (Chop) (pro-endoplasmic reticulum [ER] stress) and inflammation in perigonadal white adipose tissue (gWAT) were increased, whereas adipogenic genes and miR-379 target genes (Vegfb and Edem3) were decreased. These changes, as well as key parameters of brown adipose tissue dysfunction (including mitochondrial defects), were significantly attenuated in miR-379KO-HFD mice. WAT from obese human subjects with and without type 2 diabetes showed increased miR-379 and decreased miR-379 target genes. In cultured 3T3L1 pre-adipocytes, miR-379 inhibitors increased miR-379 targets and adipogenic genes. These data suggest that miR-379 plays an important role in HFD-induced obesity through increased adipose inflammation, mitochondrial dysfunction, and ER stress as well as impaired adipogenesis and angiogenesis. miR-379 inhibitors may be developed as novel therapies for obesity and associated complications.

Neuroimmune regulation of white adipose tissues

The white adipose tissues (WAT) are located in distinct depots throughout the body. They serve as an energy reserve, providing fatty acids for other tissues via lipolysis when needed, and function as an endocrine organ to regulate systemic metabolism. Their activities are coordinated through intercellular communications among adipocytes and other cell types such as residential and infiltrating immune cells, which are collectively under neuronal control. The adipocytes and immune subtypes including macrophages/monocytes, eosinophils, neutrophils, group 2 innate lymphoid cells (ILC2s), T and B cells, dendritic cells (DCs), and natural killer (NK) cells display cellular and functional diversity in response to the energy states and contribute to metabolic homeostasis and pathological conditions. Accumulating evidence reveals that neuronal innervations control lipid deposition and mobilization via regulating lipolysis, adipocyte size, and cellularity. Vice versa, the neuronal innervations and activity are influenced by cellular factors in the WAT. Though the literature describing adipose tissue cells is too extensive to cover in detail, we strive to highlight a selected list of neuronal and immune components in this review. The cell-to-cell communications and the perspective of neuroimmune regulation are emphasized to enlighten the potential therapeutic opportunities for treating metabolic disorders.

Inflammaging and body composition: New insights in diabetic and hypertensive elderly men

Age-related changes in the body's physiological responses play a critical role in systemic arterial hypertension (SAH) and type 2 Diabetes mellitus (T2DM). SAH and T2DM have clinically silent low-grade inflammation as a common risk factor. This inflammation has a relevant element, the excess of fatty tissue. In this scenario, little is known about how inflammatory markers interact with each other. Therefore, this work evaluated the interplay among anthropometric, biochemical, and inflammatory markers in the elderly with SAH and T2DM. Men aged 60-80 years old with SAH and T2DM were classified by body mass index (BMI) as eutrophic elderly (EE, 24 individuals) or overweight elderly (OE, 25 individuals). Body composition analysis was performed using bioimpedance. Blood samples were collected to perform inflammatory and biochemical evaluations. The cytokines IL-17A, IL-1β, IFN-y, TNF-α, and IL-10, were evaluated by ELISA. Triglycerides, total and fractions of cholesterol, and glucose were measured by spectrophotometry. Overweight elderly men had a higher glycemic index and an increase in most anthropometric markers, as well as higher means for all pro-inflammatory cytokines analyzed (IL-17A, IL-1β, IFN-y, and TNF-α) in comparison to their eutrophic elderly counterparts. However, there was a decrease in IL-10 anti-inflammatory cytokine and IL-10/IL-17A ratio compared to their eutrophic elderly counterparts. Although overweight elderly men have worsening inflammatory parameters, the magnitude of their correlations with anthropometric and biochemical parameters becomes less evident. The Bayesian networks highlight that in the eutrophic elderly, IL-17A and TNF-α are the cytokines most associated with interactions, and most of these interactions occur with biochemical parameters. It is worth highlighting the role of IFN-y in overweight elderly men. This cytokine influences IL-10 and TNF-α production, contributing to the inflammatory profile exacerbated in this group.

High-fat diet-induced obesity augments the deleterious effects of estrogen deficiency on bone: Evidence from ovariectomized mice

Several epidemiological studies have suggested that obesity complicated with insulin resistance and type 2 diabetes exerts deleterious effects on the skeleton. While obesity coexists with estrogen deficiency in postmenopausal women, their combined effects on the skeleton are poorly studied. Thus, we investigated the impact of high-fat diet (HFD) on bone and metabolism of ovariectomized (OVX) female mice (C57BL/6J). OVX or sham operated mice were fed either HFD (60%fat) or normal diet (10%fat) for 12 weeks. HFD-OVX group exhibited pronounced increase in body weight (~86% in HFD and ~122% in HFD-OVX, p < 0.0005) and impaired glucose tolerance. Bone microCT-scanning revealed a pronounced decrease in trabecular bone volume/total volume (BV/TV) (-15.6 ± 0.48% in HFD and -37.5 ± 0.235% in HFD-OVX, p < 0.005) and expansion of bone marrow adipose tissue (BMAT; +60.7 ± 9.9% in HFD vs. +79.5 ± 5.86% in HFD-OVX, p < 0.005). Mechanistically, HFD-OVX treatment led to upregulation of genes markers of senescence, bone resorption, adipogenesis, inflammation, downregulation of gene markers of bone formation and bone development. Similarly, HFD-OVX treatment resulted in significant changes in bone tissue levels of purine/pyrimidine and Glutamate metabolisms, known to play a regulatory role in bone metabolism. Obesity and estrogen deficiency exert combined deleterious effects on bone resulting in accelerated cellular senescence, expansion of BMAT and impaired bone formation leading to decreased bone mass. Our results suggest that obesity may increase bone fragility in postmenopausal women.

SIRT6 in Aging, Metabolism, Inflammation and Cardiovascular Diseases

As an important NAD⁺-dependent enzyme, SIRT6 has received significant attention since its discovery. In view of observations that SIRT6-deficient animals exhibit genomic instability and metabolic disorders and undergo early death, SIRT6 has long been considered a protein of longevity. Recently, growing evidence has demonstrated that SIRT6 functions as a deacetylase, mono-ADP-ribosyltransferase and long fatty deacylase and participates in a variety of cellular signaling pathways from DNA damage repair in the early stage to disease progression. In this review, we elaborate on the specific substrates and molecular mechanisms of SIRT6 in various physiological and pathological processes in detail, emphasizing its links to aging (genomic damage, telomere integrity, DNA repair), metabolism (glycolysis, gluconeogenesis, insulin secretion and lipid synthesis, lipolysis, thermogenesis), inflammation and cardiovascular diseases (atherosclerosis, cardiac hypertrophy, heart failure, ischemia-reperfusion injury). In addition, the most recent advances regarding SIRT6 modulators (agonists and inhibitors) as potential therapeutic agents for SIRT6-mediated diseases are reviewed.

Contribution of markers of adiposopathy and adipose cell size in predicting insulin resistance in women of varying age and adiposity

Adipose tissue (AT) dysfunctions, such as adipocyte hypertrophy, macrophage infiltration and secretory adiposopathy (low plasma adiponectin/leptin, A/L, ratio), associate with metabolic disorders. However, no study has compared the relative contribution of these markers to cardiometabolic risk in women of varying age and adiposity. Body composition, regional AT distribution, lipid-lipoprotein profile, glucose homeostasis and plasma A and L levels were determined in 67 women (age: 40-62 years; BMI: 17-41 kg/m²). Expression of macrophage infiltration marker CD68 and adipocyte size were measured from subcutaneous abdominal (SCABD) and omental (OME) fat. AT dysfunction markers correlated with most lipid-lipoprotein levels. The A/L ratio was negatively associated with fasting insulinemia and HOMA-IR, while SCABD or OME adipocyte size and SCABD CD68 expression were positively related to these variables. Combination of tertiles of largest adipocyte size and lowest A/L ratio showed the highest HOMA-IR. Multiple regression analyses including these markers and TAG levels revealed that the A/L ratio was the only predictor of fasting insulinemia and HOMA-IR. The contribution of the A/L ratio was superseded by adipose cell size in the model where the latter replaced TAGs. Finally, leptinemia was a better predictor of IR than adipocyte size and the A/L ratio in our participants sample.

S1P/S1PR3 signalling axis protects against obesity-induced metabolic dysfunction

Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid that interacts via 5 G-protein coupled receptors, S1PR1-5, to regulate signalling pathways critical to biological processes including cell growth, immune cell trafficking, and inflammation.We demonstrate that in Type 2 diabetic (T2D) subjects, plasma S1P levels significantly increased in response to the anti-diabetic drug, rosiglitazone, and, S1P levels correlated positively with measures of improved glucose homeostasis. In HFD-induced obese C57BL/6 J mice S1PR3 gene expression was increased in adipose tissues (AT) and liver compared with low fat diet (LFD)-fed counterparts. On a HFD, weight gain was similar in both S1PR3-/- mice and WT littermates; however, HFD-fed S1PR3-/- mice exhibited a phenotype of partial lipodystrophy, exacerbated insulin resistance and glucose intolerance. This worsened metabolic phenotype of HFD-fed S1PR3-/- mice was mechanistically linked with increased adipose inflammation, adipose macrophage and T-cell accumulation, hepatic inflammation and hepatic steatosis. In 3T3-L1 preadipocytes S1P increased adipogenesis and S1P-S1PR3 signalling regulated the expression of PPARγ, suggesting a novel role for this signalling pathway in the adipogenic program. These results reveal an anti-diabetic role for S1P, and, that S1P-S1PR3 signalling in the adipose and liver defends against excessive inflammation and steatosis to maintain metabolic homeostasis at key regulatory pathways.

The metabolic nature of inflammatory bowel diseases

Crohn's disease and ulcerative colitis, phenotypically comprising a spectrum of inflammatory bowel diseases (IBDs), spread globally during the westernization of lifestyle and dietary habits over the past few decades. Here, we review experimental and clinical evidence for the metabolic nature of gut inflammation in IBD and delineate distinct parallels to the inflammatory state in metabolic diseases. Experimental evidence indicates that excessive intake of specific macronutrients in a Western diet fuels an inflammatory response in the gut by exploiting sensors of innate immunity and perturbation of gut microbial metabolism. Genetic IBD risk partly affects metabolism and stress signalling of innate immunity, and immunometabolism controls susceptibility to gut inflammation. Epidemiological and clinical studies indicate that specific nutrients in the Western diet pose a risk for the development of IBD and a poor disease course. Translational studies in IBD indicate perturbation of energy metabolism in immune cells and perturbation of gut microbial metabolism, which can be shaped by diet. In turn, dietary restriction by exclusive enteral nutrition induces remission in patients with IBD. Collectively, these studies support a metabolic underpinning of gut inflammation in IBD as described for metabolic inflammation in obesity and related disorders.

Integrated analysis of microRNAs, circular RNAs, long non-coding RNAs, and mRNAs revealed competing endogenous RNA networks involved in brown adipose tissue whitening in rabbits

BACKGROUND

The brown adipose tissue (BAT) is a target for treating obesity. BAT losses thermogenic capacity and gains a "white adipose tissue-like" phenotype ("BAT whitening") under thermoneutral environments, which is a potential factor causing a low curative effect in BAT-related obesity treatments. Circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs) can act as competing endogenous RNAs (ceRNA) to mRNAs and function in various processes by sponging shared microRNAs (miRNAs). However, the roles of circRNA- and lncRNA-related ceRNA networks in regulating BAT whitening remain litter known.

RESULTS

In this study, BATs were collected from rabbits at day0 (D0), D15, D85, and 2 years (Y2). MiRNA-seq was performed to investigate miRNA changes during BAT whitening. Then, a combined analysis of circRNA-seq and whole-transcriptome sequencing was used for circRNA assembly and quantification during BAT whitening. Our data showed that 1187 miRNAs and 6204 circRNAs were expressed in the samples, and many of which were identified as significantly changed during BAT whitening. Target prediction showed that D0-selective miRNAs were significantly enriched in the Ras, MAPK, and PI3K-Akt signaling pathways, and Y2-selective miRNAs were predicted to be involved in cell proliferation. The cyclization of several circRNAs could form novel response elements of key thermogenesis miRNAs at the back-splicing junction (BSJ) sites, and in combination with a dual-luciferase reporter assay confirmed the binding between the BSJ site of novel_circ_0013792 and ocu-miR-378-5p. CircRNAs and lncRNAs have high cooperativity in sponging miRNAs during BAT whitening. Both circRNA-miRNA-mRNA and lncRNA-miRNA-mRNA triple networks were significantly involved in immune response-associated biological processes. The D15-selective circRNA might promote BAT whitening by increasing the expression of IDH2. The Y2-selective circRNA-related ceRNA network and lncRNA-related ceRNA network might regulate the formation of the WAT-like phenotype of BAT via MAPK and Ras signaling pathways, respectively.

CONCLUSIONS

Our work systematically revealed ceRNA networks during BAT whitening in rabbits and might provide new insight into BAT-based obesity treatments.

Adzuki Bean MY59 Extract Reduces Insulin Resistance and Hepatic Steatosis in High-Fat-Fed Mice via the Downregulation of Lipocalin-2

Adzuki bean is well known as a potential functional food that improves metabolic complications from obesity and diabetes. Lipocalin-2 (LCN2) has been implicated to have an important role in obesity and diabetes. However, the protective roles of adzuki bean MY59 extract (ABE) on insulin resistance and hepatic steatosis are not fully understood. In the present study, we investigated the effects of ABE on LCN2 expression in high-fat diet (HFD)-fed mice. ABE reduced HFD-induced fat mass and improved insulin resistance. In addition to hepatic steatosis, HFD-fed mice showed many apoptotic cells and neutrophils in the epididymal fat pads. However, these findings were significantly reduced by ABE supplementation. In particular, we found that increased LCN2 proteins from serum, epididymal fat pads, and liver in HFD-fed mice are significantly reduced by ABE. Furthermore, ABE reduced increased heme oxygenase-1 and superoxide dismutase-1 expressions in adipose tissue and liver in HFD-fed mice. We found that hepatic nuclear factor-kappa B (NF-κB) p65 expression in HFD-fed mice was also reduced by ABE. Thus, these findings indicate that ABE feeding could improve insulin resistance and hepatic steatosis by decreasing LCN2-mediated inflammation and oxidative stress in HFD-fed mice.

Comparison between School-Age Children with and without Obesity in Nutritional and Inflammation Biomarkers

Childhood obesity is a major health problem. We examined differences between children with obesity and normal weight in nutritional and inflammation biomarkers. A cross-sectional study was conducted among healthy children aged 10-12 years from Arab villages in Israel. Parents were interviewed regarding sociodemographic and children's health status. Body weight and height measurements were performed and weight categories were defined using the 2007 WHO growth curves. Blood samples were tested for complete blood count, levels of iron, ferritin, lipids, uric acid, and C-reactive protein (CRP). Overall, 146 children (59.0% males, mean age = 11.3 [SD = 0.5]) were enrolled. In total 43.8%, 14.1% and 42.3% of the participants had normal weight, overweight and obesity, respectively. A multivariable logistic regression model showed that children with overweight and obesity had lower iron, and HDL-C levels than children with normal weight. Levels of CRP, uric acid, LDL-C and lymphocytes were higher among children with overweight and obesity. In conclusion, our findings highlight the worse metabolic and nutritional status in overweight and obese children. Such markers play a role in metabolic syndrome, thus suggesting that metabolic syndrome might start in childhood.

Mitochondrial Stress in Metabolic Inflammation: Modest Benefits and Full Losses

Energy intake and metabolic balance are the pillars of health preservation. Overnutrition causes nonspecific, persistently low inflammatory state known as metabolic inflammation. This condition contributes to the pathophysiology of various metabolic disorders, such as atherosclerosis, obesity, diabetes mellitus, and metabolic syndrome. The mitochondria maintain the balance of energy metabolism. Excessive energy stress can lead to mitochondrial dysfunction, which promotes metabolic inflammation. The inflammatory environment further impairs mitochondrial function. Accordingly, excellent organism design keeps the body metabolically healthy in the context of mitochondrial dysfunction, and moderate mitochondrial stress can have a beneficial effect. This review summarises the research progress on the multifaceted characterisation of mitochondrial dysfunction and its role in metabolic inflammation.

MicroRNAs as Mediators of Adipose Thermogenesis and Potential Therapeutic Targets for Obesity

Obesity is a growing health problem worldwide, associated with an increased risk of multiple chronic diseases. The thermogenic activity of brown adipose tissue (BAT) correlates with leanness in adults. Understanding the mechanisms behind BAT activation and the process of white fat "browning" has important implications for developing new treatments to combat obesity. MicroRNAs (miRNAs) are small transcriptional regulators that control gene expression in various tissues, including adipose tissue. Recent studies show that miRNAs are involved in adipogenesis and adipose tissue thermogenesis. In this review, we discuss recent advances in the role of miRNAs in adipocyte thermogenesis and obesity. The potential for miRNA-based therapies for obesity and recommendations for future research are highlighted, which may help provide new targets for treating obesity and obesity-related diseases.

Regulatory Networks, Management Approaches, and Emerging Treatments of Nonalcoholic Fatty Liver Disease

The pathogenesis of NAFLD is complex and diverse, involving multiple signaling pathways and cytokines from various organs. Hepatokines, stellakines, adipokines, and myokines secreted by hepatocytes, hepatic stellate cells, adipose tissue, and myocytes play an important role in the occurrence and development of nonalcoholic fatty liver disease (NAFLD). The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) contributes to the progression of NAFLD by mediating liver inflammation, immune response, hepatocyte death, and later compensatory proliferation. In this review, we first discuss the crosstalk and interaction between hepatokines, stellakines, adipokines, and myokines and NF-κB in NAFLD. The characterization of the crosstalk of NF-κB with these factors will provide a better understanding of the molecular mechanisms involved in the progression of NAFLD. In addition, we examine new expert management opinions for NAFLD and explore the therapeutic potential of silymarin in NAFLD/NASH.

Identification of circRNAs Associated with Adipogenesis Based on RNA-Seq Data in Pigs

Adipocytes or fat cells play a vital role in the storage and release of energy in pigs, and many circular RNAs (circRNAs) have emerged as important regulators in various tissues and cell types in pigs. However, the spatio-temporal expression pattern of circRNAs between different adipose deposition breeds remains elusive. In this study, RNA sequencing (RNA-seq) produced transcriptome profiles of Western Landrace (lean-type) and Chinese Songliao black pigs (obese-type) with different thicknesses of subcutaneous fat tissues and were used to identify circRNAs involved in the regulation of adipogenesis. Gene expression analysis revealed 883 circRNAs, among which 26 and 11 circRNAs were differentially expressed between Landrace vs. Songliao pigs and high- vs. low-thickness groups, respectively. We also analyzed the interaction between circRNAs and microRNAs (miRNAs) and constructed their interaction network in adipogenesis; gene ontology classification and pathway analysis revealed two vital circRNAs, with the majority of their target genes enriched in biological functions such as fatty acids biosynthesis, fatty acid metabolism, and Wnt/TGF-β signaling pathways. These candidate circRNAs can be taken as potential targets for further experimental studies. Our results show that circRNAs are dynamically expressed and provide a valuable basis for understanding the molecular mechanism of circRNAs in pig adipose biology.

Extracellular vesicles biogenesis, isolation, manipulation and genetic engineering for potential in vitro and in vivo therapeutics: An overview

The main goals of medicine consist of early detection and effective treatment of different diseases. In this regard, the rise of exosomes as carriers of natural biomarkers has recently attracted a lot of attention and managed to shed more light on the future of early disease diagnosis methods. Here, exosome biogenesis, its role as a biomarker in metabolic disorders, and recent advances in state-of-art technologies for exosome detection and isolation will be reviewed along with future research directions and challenges regarding the manipulation and genetic engineering of exosomes for potential in vitro and in vivo disease diagnosis approaches.

Gut microbiota dysbiosis as an inflammaging condition that regulates obesity-related retinopathy and nephropathy

Diabetes-specific microvascular disease is a leading cause of blindness, renal failure and nerve damage. Epidemiological data demonstrated that the high morbidity of T2DM occurs as a result of obesity and gradually develops into serious complications. To date, the mechanisms that underlie this observation are still ill-defined. In view of the effect of obesity on the gut microflora, Lepr^db/db mice underwent antibiotic treatment and microbiota transplants to modify the gut microbiome to investigate whether microbes are involved in the development of diabetic nephropathy (DN) and/or diabetic retinopathy (DR). The mouse feces were collected for bacterial 16S ribosomal RNA gene sequencing. Cytokines including TNF-α, TGF-β1, IFN-γ, IL-1β, IL-6, IL-17A, IL-10, and VEGFA were detected by enzyme-linked immunosorbent assay (ELISA), flow cytometry, real-time PCR and immunofluorescent assay. Eyes and kidney were collected for histopathological assay. Intestinal permeability was also detected using Evans Blue. The results showed that obesity influenced metabolic variables (including fast/fed glucose, insulin, and triglyceride), retinopathy and nephropathy, and the gut microbiota. Obesity mainly reduced the ratio of Bacteroidetes/Firmicutes and influenced relative abundance of Proteobacteria, Actinobacteria, and Spirochetes. Obesity also increased intestinal permeability, metabolic endotoxemia, cytokines, and VEGFA. Microbiota transplants confirm that obesity aggravates retinopathy and nephropathy through the gut microbiota. These findings suggest that obesity exacerbates retinopathy and nephropathy by inducing gut microbiota dysbiosis, which further enhanced intestinal permeability and chronic low-grade inflammation.

TBK1-mTOR Signaling Attenuates Obesity-Linked Hyperglycemia and Insulin Resistance

The innate immune kinase TBK1 (TANK-binding kinase 1) responds to microbial-derived signals to initiate responses against viral and bacterial pathogens. More recent work implicates TBK1 in metabolism and tumorigenesis. The kinase mTOR (mechanistic target of rapamycin) integrates diverse environmental cues to control fundamental cellular processes. Our prior work demonstrated in cells that TBK1 phosphorylates mTOR (on S2159) to increase mTORC1 and mTORC2 catalytic activity and signaling. Here we investigate a role for TBK1-mTOR signaling in control of glucose metabolism in vivo. We find that mice with diet-induced obesity (DIO) but not lean mice bearing a whole-body "TBK1-resistant" Mtor S2159A knock-in allele (MtorA/A) display exacerbated hyperglycemia and systemic insulin resistance with no change in energy balance. Mechanistically, Mtor S2159A knock-in in DIO mice reduces mTORC1 and mTORC2 signaling in response to insulin and innate immune agonists, reduces anti-inflammatory gene expression in adipose tissue, and blunts anti-inflammatory macrophage M2 polarization, phenotypes shared by mice with tissue-specific inactivation of TBK1 or mTOR complexes. Tissues from DIO mice display elevated TBK1 activity and mTOR S2159 phosphorylation relative to lean mice. We propose a model whereby obesity-associated signals increase TBK1 activity and mTOR phosphorylation, which boost mTORC1 and mTORC2 signaling in parallel to the insulin pathway, thereby attenuating insulin resistance to improve glycemic control during diet-induced obesity.

Multiomics reveal unique signatures of human epiploic adipose tissue related to systemic insulin resistance

OBJECTIVE

Human white adipose tissue (AT) is a metabolically active organ with distinct depot-specific functions. Despite their locations close to the gastrointestinal tract, mesenteric AT and epiploic AT (epiAT) have only scarcely been investigated. Here, we aim to characterise these ATs in-depth and estimate their contribution to alterations in whole-body metabolism.

DESIGN

Mesenteric, epiploic, omental and abdominal subcutaneous ATs were collected from 70 patients with obesity undergoing Roux-en-Y gastric bypass surgery. The metabolically well-characterised cohort included nine subjects with insulin sensitive (IS) obesity, whose AT samples were analysed in a multiomics approach, including methylome, transcriptome and proteome along with samples from subjects with insulin resistance (IR) matched for age, sex and body mass index (n=9). Findings implying differences between AT depots in these subgroups were validated in the entire cohort (n=70) by quantitative real-time PCR.

RESULTS

While mesenteric AT exhibited signatures similar to those found in the omental depot, epiAT was distinct from all other studied fat depots. Multiomics allowed clear discrimination between the IS and IR states in all tissues. The highest discriminatory power between IS and IR was seen in epiAT, where profound differences in the regulation of developmental, metabolic and inflammatory pathways were observed. Gene expression levels of key molecules involved in AT function, metabolic homeostasis and inflammation revealed significant depot-specific differences with epiAT showing the highest expression levels.

CONCLUSION

Multi-omics epiAT signatures reflect systemic IR and obesity subphenotypes distinct from other fat depots. Our data suggest a previously unrecognised role of human epiploic fat in the context of obesity, impaired insulin sensitivity and related diseases.

CX3CL1/CX3CR1 interaction protects against lipotoxicity-induced nonalcoholic steatohepatitis by regulating macrophage migration and M1/M2 status

BACKGROUND AND OBJECTIVES

Chemokine (C-X3-C motif) ligand 1 (CX3CL1) and its receptor CX3CR1 regulate the migration and activation of immune cells and are involved in the pathogenesis of nonalcoholic steatohepatitis (NASH), but the mechanism remains elusive. Here, the roles of CX3CL1/CX3CR1 in the macrophage migration and polarization in the livers of NASH mice were investigated.

METHODS AND RESULTS

The expression of Cx3cl1 and Cx3cr1 was markedly upregulated in the livers of lipotoxicity-induced NASH mice. CX3CR1 was predominantly expressed by F4/80⁺ macrophages and to a lesser degree by hepatic stellate cells or endothelial cells in the livers of NASH mice. Flow cytometry analysis revealed that, compared with chow-fed mice, NASH mice exhibited a significant increase in CX3CR1⁺ expression by liver macrophages (LMs), particularly M1 LMs. CX3CR1 deficiency caused a significant increase in inflammatory monocyte/macrophage infiltration and a shift toward M1 dominant macrophages in the liver, thereby exacerbating the progression of NASH. Moreover, transplantation of Cx3cr1^-/- bone marrow was sufficient to cause glucose intolerance, inflammation, and fibrosis in the liver. In addition, deletion of CCL2 in Cx3cr1^-/- mice alleviated NASH progression by decreasing macrophage infiltration and inducing a shift toward M2 dominant LMs. Importantly, overexpression of CX3CL1 in vivo protected against hepatic fibrosis in NASH.

CONCLUSION

Pharmacological therapy targeting liver CX3CL1/CX3CR1 signaling might be a candidate for the treatment of NASH.

Nutritional activities of luteolin in obesity and associated metabolic diseases: an eye on adipose tissues

Obesity is characterized by excessive body fat accumulation and is a high-risk factor for metabolic comorbidities, including type 2 diabetes, nonalcoholic fatty liver disease, and cardiovascular disease. In lean individuals, adipose tissue (AT) is not only an important regulatory organ for energy storage and metabolism, but also an indispensable immune and endocrine organ. The sustained energy imbalance induces adipocyte hypotrophy and hyperplasia as well as AT remodeling, accompanied by chronic low-grade inflammation and adipocytes dysfunction in AT, ultimately leading to systemic insulin resistance and ectopic lipid deposition. Luteolin is a natural flavonoid widely distributed in fruits and vegetables and possesses multifold biological activities, such as antioxidant, anticancer, and anti-inflammatory activities. Diet supplementation of this flavonoid has been reported to inhibit AT lipogenesis and inflammation as well as the ectopic lipid deposition, increase AT thermogenesis and systemic energy expenditure, and finally improve obesity and associated metabolic diseases. The purpose of this review is to reveal the nutritional activities of luteolin in obesity and its complications with emphasis on its action on AT energy metabolism, immunoregulation, and endocrine intervention.

Netrin-1 Promotes Visceral Adipose Tissue Inflammation in Obesity and Is Associated with Insulin Resistance

Netrin (NTN)-1 exhibits pro- and anti-inflammatory roles in different settings, playing important roles in the obesity-associated low-grade chronic inflammation. We aimed to determine the impact of NTN-1 on obesity and obesity-associated type 2 diabetes, as well as its role in visceral adipose tissue (VAT) inflammation. A total of 91 subjects were enrolled in this case-control study. Circulating levels of NTN-1 and its receptor neogenin (NEO)-1 were determined before and after weight loss achieved by caloric restriction and bariatric surgery. mRNA levels of NTN1 and NEO1 were assessed in human VAT, liver, and peripheral blood mononuclear cells. In vitro studies in human visceral adipocytes and human monocytic leukemia cells (THP-1)-derived macrophages were performed to analyze the impact of inflammation-related mediators on the gene expression levels of NTN1 and its receptor NEO1 as well as the effect of NTN-1 on inflammation. Increased (p < 0.001) circulating concentrations of NTN-1 in obesity decreased (p < 0.05) after diet-induced weight loss being also associated with a reduction in glucose (p < 0.01) and insulin levels (p < 0.05). Gene expression levels of NTN1 and NEO1 were upregulated (p < 0.05) in the VAT from patients with obesity with the highest expression in the stromovascular fraction cells compared with mature adipocytes (p < 0.01). NTN1 expression levels were enhanced (p < 0.01) under hypoxia and by inflammatory factors in both adipocytes and macrophages. Adipocyte-conditioned media strongly upregulated (p < 0.001) the mRNA levels of NTN1 in macrophages. The treatment of adipocytes with NTN-1 promoted the upregulation (p < 0.05) of pro-inflammatory and chemotactic molecules as well as its receptor NEO1. Collectively, these findings suggest that NTN-1 regulates VAT chronic inflammation and insulin resistance in obesity.