Recent insights on modulation of inflammasomes by adipokines: a critical event for the pathogenesis of obesity and metabolism-associated diseases. Arch Pharm Res. 2020;43:997-1016. [PMID: 33078304 DOI: 10.1007/s12272-020-01274-7]

NLRP3 inflammasome activation contributes to the development of the pro-fibrotic phenotype of lung fibroblasts

Idiopathic pulmonary fibrosis (IPF) is an irreversible progressive interstitial lung disease of unknown cause. The poorly understood pathophysiology of IPF poses substantial challenges to the development of effective anti-lung fibrotic drugs. The NLRP3 inflammasome, a key component of the innate immune system, has recently been linked to the pathogenesis of lung fibrosis. However, the specific contributions of NLRP3 inflammasomes to determination of the pro-fibrotic phenotype of lung fibroblasts, which play a central role in the production of extracellular matrix protein, remain to be investigated. Therefore, the present study was performed to elucidate the involvement of NLRP3 inflammasome signalling pathways in modulation of lung fibroblast proliferation and differentiation. We found that activation of NLRP3 inflammasomes increased in lung fibroblasts derived from individuals with pulmonary fibrosis and in normal lung fibroblasts stimulated with transforming growth factor β and platelet-derived growth factor. Importantly, blockage of NLRP3 inflammasome signalling, either by gene silencing of NLRP3 or using pharmacological inhibitors of NLRP3, caspase-1, or IL-1 receptor, inhibited the proliferation, differentiation, and extracellular matrix protein synthesis of activated lung fibroblasts. Moreover, induction of the reactive oxygen species/thioredoxin-interacting protein axis, an upstream signalling pathway of NLRP3 inflammasomes, was essential for maintenance of the pro-fibrotic phenotype of lung fibroblasts. Interestingly, treatments with pharmacological inhibitors of NLRP3 inflammasomes prevented the progression of bleomycin-induced pulmonary fibrosis in mice. Collectively, these findings suggest that aberrant activation of NLRP3 inflammasomes is a critical event in the pathogenesis of IPF and that targeting NLRP3 inflammasomes may serve as a therapeutic strategy for IPF.

Chemerin in the Spotlight: Revealing Its Multifaceted Role in Acute Myocardial Infarction

Chemerin, an adipokine known for its role in adipogenesis and inflammation, has emerged as a significant biomarker in cardiovascular diseases, including acute myocardial infarction (AMI). Recent studies have highlighted chemerin's involvement in the pathophysiological processes of coronary artery disease (CAD), where it modulates inflammatory responses, endothelial function, and vascular remodelling. Elevated levels of chemerin have been associated with adverse cardiovascular outcomes, including increased myocardial injury, left ventricular dysfunction, and heightened inflammatory states post-AMI. This manuscript aims to provide a comprehensive review of the current understanding of chemerin's role in AMI, detailing its molecular mechanisms, clinical implications, and potential as a biomarker for diagnosis and prognosis. Additionally, we explore the therapeutic prospects of targeting chemerin pathways to mitigate myocardial damage and improve clinical outcomes in AMI patients. By synthesizing the latest research findings, this review seeks to elucidate the multifaceted role of chemerin in AMI and its promise as a target for innovative therapeutic strategies.

Effects of combustible cigarettes and electronic nicotine delivery systems on immune cell-driven inflammation: Evidences from diabetic patients and multiple low dose streptozotocin-treated diabetic mice

Considering detrimental impacts of combustible cigarettes (CCs) on the exacerbation of diabetes mellitus (DM), a significant number of DM patients have substituted CCs with electronic nicotine delivery systems (ENDS). Herewith, we compared CCs and ENDS-dependent modulation of immune cell-driven inflammation in DM patients who used ENDS (DMENDS), CCs (DMCC) or were non-smokers (DMAIR), paving the way for the better understanding of ENDS-induced biological effects. Multiple low dose streptozotocin (MLD-STZ)-induced mice model of DM was used to support clinical findings. Both CCs and ENDS aggravated MLD-STZ-induced DM. Pancreatic injury and inflammation were more severe in CC-exposed than in ENDS-exposed diabetic mice. CCs promoted activation of NLRP3 inflammasome, enhanced production of inflammatory cytokines in neutrophils, macrophages and remarkably improved antigen presenting capacity of dendritic cells which resulted in the expansion of TNF-α, IFN-γ and IL-17-producing Th1 and Th17 lymphocytes, NK and NKT cells. Compared to CCs, ENDS more intensively promoted expansion of FoxP3-expressing, IL-10-producing NK and NKT cells and triggered less intense systemic inflammatory response in diabetic animals. Similar findings were observed in DM patients. The highest numbers of inflammatory, TNF-α and IL-1β-producing neutrophils and monocytes, TNF-α and IFN-γ-producing T lymphocytes, NK and NKT cells were determined in the blood of DMCC patients, while total number of immunosuppressive, TGF-β-producing CD3 + CD4 + T cells was the highest in the blood of DMENDS patients. In conclusion, although both CC and ENDS aggravate on-going inflammation in DM, ENDS have weaker capacity to induce production of inflammatory cytokines in immune cells than CCs.

Immune cells crosstalk Pathways, and metabolic alterations in Idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) presents a challenging progression characterized by lung tissue scarring and abnormal extracellular matrix deposition. This review examines the influence of immune responses, emphasizing their complex role in initiating and perpetuating fibrosis. It highlights how metabolic pathways modulate immune cell function during IPF. Immune cell modulation holds promise in managing pulmonary fibrosis (PF). Inhibiting neutrophil recruitment and monitoring mast cell levels offer insights into PF progression. Low-dose IL-2 therapy and regulation of fibroblast recruitment present potential therapeutic avenues, while the role of innate lymphoid cells (ILC2s) in allergic lung inflammation sheds light on disease mechanisms. The review focuses on metabolic reprogramming's role in shaping immune cell function during IPF progression. While some immune cells use glycolysis for pro-inflammatory responses, others favor fatty acid oxidation for regulatory functions. Targeting specialized pro-resolving lipid mediators (SPMs) presents significant potential for managing fibrotic disorders. Additionally, it highlights the pivotal role of amino acid metabolism in synthesizing serine and glycine as crucial regulators of collagen production and exploring the interconnectedness of lipid metabolism, mitochondrial dysfunction, and adipokines in driving fibrotic processes. Moreover, the review discusses the impact of metabolic disorders such as obesity and diabetes on lung fibrosis. Advocating for a holistic approach, it emphasizes the importance of considering this interplay between immune cell function and metabolic pathways in developing effective and personalized treatments for IPF.

Determinants of Carotid Wall Echolucency in a Cohort of European High Cardiovascular Risk Subjects: A Cross-Sectional Analysis of IMPROVE Baseline Data

Echolucency, a measure of plaque instability associated with increased cardiovascular risk, can be assessed in both the carotid plaque and the plaque-free common carotid intima-media (IM) complex as a gray-scale median (plaque-GSM and IM-GSM, respectively). The impact of specific vascular risk factors on these two phenotypes remains uncertain, including the nature and extent of their influence. This study aims to seek the determinants of plaque-GSM and IM-GSM. Plaque-GSM and IM-GSM were measured in subjects from the IMPROVE study cohort (aged 54-79, 46% men) recruited in five European countries. Plaque-GSM was measured in subjects who had at least one IMTmax ≥ 1.5 mm (n = 2138), whereas IM-GSM was measured in all subjects included in the study (n = 3188). Multiple regression with internal cross-validation was used to find independent predictors of plaque-GSM and IM-GSM. Plaque-GSM determinants were plaque-size (IMTmax), and diastolic blood pressure. IM-GSM determinants were the thickness of plaque-free common carotid intima-media complex (PF CC-IMTmean), height, systolic blood pressure, waist/hip ratio, treatment with fibrates, mean corpuscular volume, treatment with alpha-2 inhibitors (sartans), educational level, and creatinine. Latitude, and pack-yearscode were determinants of both plaque-GSM and IM-GSM. The overall models explain 12.0% of plaque-GSM variability and 19.7% of IM-GSM variability. A significant correlation (r = 0.51) was found between plaque-GSM and IM-GSM. Our results indicate that IM-GSM is a weighty risk marker alternative to plaque-GSM, offering the advantage of being readily measurable in all subjects, including those in the early phases of atherosclerosis where plaque occurrence is relatively infrequent.

The role of adipokines in osteoporosis management: a mini review

The prevalence of osteoporosis has been on the rise globally. With ageing populations, research has sought therapeutic solutions in novel areas. One such area is that of the adipokines. Current literature points to an important role for these chemical mediators in relation to bone metabolism. Well-established adipokines have been broadly reported upon. These include adiponectin and leptin. However, other novel adipokines such as visfatin, nesfatin-1, meteorin-like protein (Metrnl), apelin and lipocalin-2 are starting to be addressed pre-clinically and clinically. Adipokines hold pro-inflammatory and anti-inflammatory properties that influence the pathophysiology of various bone diseases. Omentin-1 and vaspin, two novel adipokines, share cardioprotective effects and play essential roles in bone metabolism. Studies have reported bone-protective effects of omentin-1, whilst others report negative associations between omentin-1 and bone mineral density. Lipocalin-2 is linked to poor bone microarchitecture in mice and is even suggested to mediate osteoporosis development from prolonged disuse. Nesfatin-1, an anorexigenic adipokine, has been known to preserve bone density. Animal studies have demonstrated that nesfatin-1 treatment limits bone loss and increases bone strength, suggesting exogenous use as a potential treatment for osteopenic disorders. Pre-clinical studies have shown adipokine apelin to have a role in bone metabolism, mediated by the enhancement of osteoblast genesis and the inhibition of programmed cell death. Although many investigations have reported conflicting findings, sufficient literature supports the notion that adipokines have a significant influence on the metabolism of bone. This review aims at highlighting the role of novel adipokines in osteoporosis while also discussing their potential for treating osteoporosis.

Progress in research of type 2 diabetes with nonalcoholic fatty liver in traditional Chinese and Western medicine

By analyzing the recent relevant literature on type 2 diabetes with nonalcoholic fatty liver disease, this paper summarizes its etiology, pathogenesis, syndrome differentiation and treatment, clinical treatment, and other aspects from the perspective of traditional Chinese medicine (TCM) and Western medicine. There has been some progress in the treatment of this disease in both TCM and Western medicine, but further in-depth study is required to explore its pathogenesis. Moreover, the etiology, pathogenesis, and syndrome differentiation of this disease in TCM are not yet unified, and large-scale, multicenter, and prospective clinical research is insufficient. There is also a lack of research on the action and targets of TCM in this disease.

Adiponectin restores the obesity-induced impaired immunomodulatory function of mesenchymal stromal cells via glycolytic reprogramming

Obesity has been known to negatively modulate the life-span and immunosuppressive potential of mesenchymal stromal cells (MSC). However, it remains unclear what drives the compromised potency of obese MSC. In this study, we examined the involvement of adiponectin, an adipose tissue-derived hormone, in obesity-induced impaired therapeutic function of MSC. Diet-induced obesity leads to a decrease in serum adiponectin, accompanied by impairment of survival and immunomodulatory effects of adipose-derived MSC (ADSC). Interestingly, priming with globular adiponectin (gAcrp) improved the immunomodulatory potential of obese ADSC. Similar effects were also observed in lean ADSC. In addition, gAcrp potentiated the therapeutic effectiveness of ADSC in a mouse model of DSS-induced colitis. Mechanistically, while obesity inhibited the glycolytic capacity of MSC, gAcrp treatment induced a metabolic shift toward glycolysis through activation of adiponectin receptor type 1/p38 MAPK/hypoxia inducible factor-1α axis. These findings suggest that activation of adiponectin signaling is a promising strategy for enhancing the therapeutic efficacy of MSC against immune-mediated disorders.

TNFα-induced NLRP3 inflammasome mediates adipocyte dysfunction and activates macrophages through adipocyte-derived lipocalin 2

BACKGROUND AND AIMS

Obesity is a state of chronic low-grade systemic inflammation. Recent studies showed that NLRP3 inflammasome initiates metabolic dysregulation in adipose tissues, primarily through activation of adipose tissue infiltrated macrophages. However, the mechanism of NLRP3 activation and its role in adipocytes remains elusive. Therefore, we aimed to examine the activation of TNFα-induced NLRP3 inflammasome in adipocytes and its role on adipocyte metabolism and crosstalk with macrophages.

METHODS

The effect of TNFα on adipocyte NLRP3 inflammasome activation was measured. Caspase-1 inhibitor (Ac-YVAD-cmk) and primary adipocytes from NLRP3 and caspase-1 knockout mice were utilized to block NLRP3 inflammasome activation. Biomarkers were measured by using real-time PCR, western blotting, immunofluorescence staining, and enzyme assay kits. Conditioned media from TNFα-stimulated adipocytes was used to establish the adipocyte-macrophage crosstalk. Chromatin immunoprecipitation assay was used to identify the role of NLRP3 as a transcription factor. Mouse and human adipose tissues were collected for correlation analysis.

RESULTS

TNFα treatment induced NLRP3 expression and caspase-1 activity in adipocytes, partly through autophagy dysregulation. The activated adipocyte NLRP3 inflammasome participated in mitochondrial dysfunction and insulin resistance, as evidenced by the amelioration of these effects in Ac-YVAD-cmk treated 3T3-L1 cells or primary adipocytes isolated from NLRP3 and caspase-1 knockout mice. Particularly, the adipocyte NLRP3 inflammasome was involved in glucose uptake regulation. Also, TNFα induced expression and secretion of lipocalin 2 (Lcn2) in a NLRP3-dependent manner. NLRP3 could bind to the promoter and transcriptionally regulate Lcn2 in adipocytes. Treatment with adipocyte conditioned media revealed that adipocyte-derived Lcn2 was responsible for macrophage NLRP3 inflammasome activation, working as a second signal. Adipocytes isolated from high-fat diet mice and adipose tissue from obese individuals showed a positive correlation between NLRP3 and Lcn2 gene expression.

CONCLUSIONS

This study highlights the importance of adipocyte NLRP3 inflammasome activation and novel role of TNFα-NLRP3-Lcn2 axis in adipose tissue. It adds rational for the current development of NLRP3 inhibitors for treating obesity-induced metabolic diseases.

Adiponectin negatively regulates pigmentation, Wnt/β-catenin and HGF/c-Met signalling within human scalp hair follicles ex vivo

Adiponectin reportedly stimulates proliferation and elongation of human scalp hair follicles (HFs) ex vivo. In the current study, we investigated how adiponectin oligomers produced by perifollicular dermal white adipose tissue (dWAT), a potent source of adiponectin isoforms, influence human HF proliferation and pigmentation. To do so, we treated microdissected, organ-cultured HFs in the presence or absence of dWAT with a recombinant human adiponectin oligomer mix, or inhibited dWAT-derived adiponectin using a neutralizing antibody. Multiplex qPCR (Fluidigm) revealed that adiponectin oligomers downregulated pigmentation genes KITLG, PMEL and TYRP1 and Wnt genes AXIN2, LEF1 and WNT10B. In situ hybridization showed that adiponectin downregulated AXIN2 and LEF1, and up-regulated DKK1 within the dermal papilla (DP), a highly unusual transcriptional profile for a putative hair growth-promoting agent. Adiponectin oligomers also downregulated protein expression of the HGF receptor c-Met within the matrix and DP. However, adiponectin did not alter hair matrix keratinocyte proliferation within 48 h ex vivo, irrespective of the presence/absence of dWAT; HF pigmentation (Masson-Fontana histochemistry, tyrosinase activity) was also unchanged. In contrast, neutralizing adiponectin isoforms within HF + dWAT increased proliferation, melanin content and tyrosinase activity but resulted in fewer melanocytes and melanocytic dendrites, as assessed by gp100 immunostaining. These seemingly contradictory effects suggest that adiponectin exerts complex effects upon human HF biology, likely in parallel with the pro-pigmentation effects of dWAT- and DP-derived HGF. Our data suggest that dWAT-derived ratios of adiponectin isoforms and the cleaved, globular version of adiponectin may in fact determine how adiponectin impacts upon follicular pigmentation and growth.

Modulation of NLRP3 inflammasomes activation contributes to improved survival and function of mesenchymal stromal cell spheroids

Mesenchymal stem cells (MSCs) are ubiquitous multipotent cells that exhibit significant therapeutic potentials in a variety of disorders. Nevertheless, their clinical efficacy is limited owing to poor survival, low rate of engraftment, and impaired potency upon transplantation. Spheroidal three-dimensional (3D) culture of MSCs (MSC3D) has been proven to better preserve their in vivo functional properties. However, the molecular mechanisms underlying the improvement in MSC function by spheroid formation are not clearly understood. NLRP3 inflammasomes, a key component of the innate immune system, have recently been shown to play a role in cell fate decision of MSCs. The present study examined the role of NLRP3 inflammasomes in the survival and potency of MSC spheroids. We found that MSC3D led to decreased activation of NLRP3 inflammasomes through alleviation of ER stress in an autophagy-dependent manner. Importantly, downregulation of NLRP3 inflammasomes signaling critically contributes to the enhanced survival rate in MSC3D through modulation of pyroptosis and apoptosis. The critical role of NLRP3 inflammasome suppression in the enhanced therapeutic efficacy of MSC spheroids was further confirmed in an in vivo mouse model of DSS-induced colitis. These findings suggest that 3D culture confers survival and functional advantages to MSCs by suppressing NLRP3 inflammasome activation.

Cathepsin B maturation plays a critical role in leptin-induced hepatic cancer cell growth through activation of NLRP3 inflammasomes

Leptin, an adipose tissue-derived hormone, exhibits potent tumor promoting effects through various mechanisms. Cathepsin B, a member of the lysosomal cysteine proteases, has been shown to modulate the growth of cancer cells. In this study, we have investigated the role of cathepsin B signaling in leptin-induced hepatic cancer growth. Leptin treatment caused significant increase in the levels of active cathepsin B through the axis of endoplasmic reticulum stress and autophagy induction without significant effects on pre- and pro-forms of cathepsin B. Interestingly, inhibition of cathepsin B signaling by gene silencing or treatment with a selective pharmacological inhibitor (CA-074) prevented leptin-enhanced viability of hepatic cancer cell and suppressed progression of cell cycle, indicating the critical role of cathepsin B in leptin-induced hepatic cancer growth. We have further observed that maturation of cathepsin B is required for NLRP3 inflammasomes activation, which is implicated in the growth of hepatic cancer cell. The crucial roles of cathepsin B maturation in leptin-induced hepatic cancer growth and NLRP3 inflammasomes activation were confirmed in an in vivo HepG2 tumor xenograft model. Taken together, these results demonstrate that cathepsin B signaling plays a pivotal role in leptin-induced hepatic cancer cell growth by activating NLRP3 inflammasomes.

Human Obesity Attenuates Cardioprotection Conferred by Adipose Tissue-Derived Mesenchymal Stem/Stromal Cells

To explore the impact of obesity on reparative potency of adipose tissue-derived mesenchymal stromal/stem cells (A-MSC) in hypertensive cardiomyopathy, A-MSC were harvested from subcutaneous fat of obese and age-matched non-obese human subjects during bariatric or kidney donation surgeries, and then injected into mice 2 weeks after inducing renovascular hypertension (RVH) or sham surgery. Two weeks later, left ventricular (LV) function and deformation were estimated in vivo by micro-magnetic resonance imaging and myocardial damage ex vivo. Blood pressure and myocardial wall thickening were elevated in RVH + Vehicle and normalized only by lean-A-MSC. Both A-MSC types reduced LV mass and normalized the reduced LV peak strain radial in RVH, yet obese-A-MSC also impaired LV systolic function. A-MSC alleviated myocardial tissue damage in RVH, but lean-A-MSC decreased oxidative stress more effectively. Obese-A-MSC also showed increased cellular inflammation in vitro. Therefore, obese-A-MSC are less effective than lean-A-MSC in blunting hypertensive cardiomyopathy in mice with RVH.

Adipokines at the crossroads of obesity and mesenchymal stem cell therapy

Mesenchymal stem cell (MSC) therapy is an emerging treatment strategy to counteract metabolic syndromes, including obesity and its comorbid disorders. However, its effectiveness is challenged by various factors in the obese environment that negatively impact MSC survival and function. The identification of these detrimental factors will provide opportunities to optimize MSC therapy for the treatment of obesity and its comorbidities. Dysregulated production of adipokines, a group of cytokines and hormones derived from adipose tissue, has been postulated to play a pivotal role in the development of obesity-associated complications. Intriguingly, adipokines have also been implicated in the modulation of viability, self-renewal, proliferation, and other properties of MSC. However, the involvement of adipokine imbalance in impaired MSC functionality has not been completely understood. On the other hand, treatment of obese individuals with MSC can restore the serum adipokine profile, suggesting the bidirectionality of the adipokine-MSC relationship. In this review, we aim to discuss the current knowledge on the central role of adipokines in the crosstalk between obesity and MSC dysfunction. We also summarize recent advances in the use of MSC for the treatment of obesity-associated diseases to support the hypothesis that adipokines modulate the benefits of MSC therapy in obese patients.

Recent advances in the crosstalk between adipose, muscle and bone tissues in fish

Control of tissue metabolism and growth involves interactions between organs, tissues, and cell types, mediated by cytokines or direct communication through cellular exchanges. Indeed, over the past decades, many peptides produced by adipose tissue, skeletal muscle and bone named adipokines, myokines and osteokines respectively, have been identified in mammals playing key roles in organ/tissue development and function. Some of them are released into the circulation acting as classical hormones, but they can also act locally showing autocrine/paracrine effects. In recent years, some of these cytokines have been identified in fish models of biomedical or agronomic interest. In this review, we will present their state of the art focusing on local actions and inter-tissue effects. Adipokines reported in fish adipocytes include adiponectin and leptin among others. We will focus on their structure characteristics, gene expression, receptors, and effects, in the adipose tissue itself, mainly regulating cell differentiation and metabolism, but in muscle and bone as target tissues too. Moreover, lipid metabolites, named lipokines, can also act as signaling molecules regulating metabolic homeostasis. Regarding myokines, the best documented in fish are myostatin and the insulin-like growth factors. This review summarizes their characteristics at a molecular level, and describes both, autocrine effects and interactions with adipose tissue and bone. Nonetheless, our understanding of the functions and mechanisms of action of many of these cytokines is still largely incomplete in fish, especially concerning osteokines (i.e., osteocalcin), whose potential cross talking roles remain to be elucidated. Furthermore, by using selective breeding or genetic tools, the formation of a specific tissue can be altered, highlighting the consequences on other tissues, and allowing the identification of communication signals. The specific effects of identified cytokines validated through in vitro models or in vivo trials will be described. Moreover, future scientific fronts (i.e., exosomes) and tools (i.e., co-cultures, organoids) for a better understanding of inter-organ crosstalk in fish will also be presented. As a final consideration, further identification of molecules involved in inter-tissue communication will open new avenues of knowledge in the control of fish homeostasis, as well as possible strategies to be applied in aquaculture or biomedicine.

Mitophagy Induction and Aryl Hydrocarbon Receptor-Mediated Redox Signaling Contribute to the Suppression of Breast Cancer Cell Growth by Taloxifene via Regulation of Inflammasomes Activation

Aims: Raloxifene, a selective estrogen receptor (ER) modulator, has been reported to exert the tumor-suppressive effects in both ER-positive and ER-negative cancer cells; however, the mechanisms underlying its ER-independent anti-cancer effects are poorly understood. The NLRP3 inflammasome, a critical component of the innate immune system, has recently received growing attention owing to its multifaceted roles in various aspects of cancer development. The present study aimed at examining the involvement of NLRP3 inflammasomes in the anti-breast cancer effects of raloxifene and its underlying mechanisms. Results: Raloxifene significantly inhibited the activation of NLRP3 inflammasomes in various breast cancer cell lines. Importantly, forced expression of a gain-of-function variant of NLRP3 rescued breast cancer cells from growth arrest by raloxifene, suggesting that the suppression of NLRP3 inflammasomes activation mediates the raloxifene-induced inhibition of breast cancer growth. Mechanistically, raloxifene suppressed NLRP3 inflammasomes activation by lowering the cellular levels of reactive oxygen species (ROS) through the modulation of redox signaling mediated via aryl hydrocarbon receptor (AhR)-nuclear factor erythroid 2-related factor 2 (Nrf2)-heme oxygenase-1 (HO-1) axis or the impaired generation of mitochondrial ROS in a mitophagy-dependent manner. Further, the blockage of AhR signaling or inhibition of mitophagy abolished the tumor-suppressive effect of raloxifene in a human breast tumor xenograft model. Innovation: We elucidate a novel molecular mechanism underlying the breast tumor suppressing effect of raloxifene. Conclusion: The results observed in this study suggest that the modulation of NLRP3 inflammasomes activation is a critical event in the inhibition of breast tumor growth by raloxifene. Antioxid. Redox Signal. 37, 1030-1050.

The metabolic hormone adiponectin affects the correlation between nutritional status and pneumococcal vaccine response in vulnerable indigenous children

Background

Almost 200 million children worldwide are either undernourished or overweight. Only a few studies have addressed the effect of variation in nutritional status on vaccine response. We previously demonstrated an association between stunting and an increased post-vaccination 13-valent pneumococcal conjugate vaccine (PCV13) response. In this prospective study, we assessed to what extent metabolic hormones may be a modifier in the association between nutritional status and PCV13 response.

Methods

Venezuelan children aged 6 weeks to 59 months were vaccinated with a primary series of PCV13. Nutritional status and serum levels of leptin, adiponectin and ghrelin were measured upon vaccination and their combined effect on serum post-vaccination antibody concentrations was assessed by generalized estimating equations multivariable regression analysis.

Results

A total of 210 children were included, of whom 80 were stunted, 81 had a normal weight and 49 were overweight. Overweight children had lower post-vaccination antibody concentrations than normal weight children (regression coefficient -1.15, 95% CI -2.22 –-0.072). Additionally, there was a significant adiponectin-nutritional status interaction. In stunted children, higher adiponectin serum concentrations were associated with lower post-PCV13 antibody concentrations (regression coefficient -0.19, 95% CI -0.24 –-0.14) while the opposite was seen in overweight children (regression coefficient 0.14, 95% CI 0.049–0.22).

Conclusion

Metabolic hormones, in particular adiponectin, may modify the effect of nutritional status on pneumococcal vaccine response. These findings emphasize the importance of further research to better understand the immunometabolic pathways underlying vaccine response and enable a future of optimal personalized vaccination schedules.

Jinlida Granules Reduce Obesity in db/db Mice by Activating Beige Adipocytes

Recent studies indicate existence of beige adipocytes in adults. Upon activation, beige adipocytes burn energy for thermogenesis and contribute to regulation of energy balance. In this study, we have analyzed whether Jinlida granules (JLD) could activate beige adipocytes. JLD suspended in 0.5% carboxymethyl cellulose (CMC) was gavage fed to db/db mice at a daily dose of 3.8 g/kg. After 10 weeks, body weight, biochemical, and histological analyses were performed. In situ hybridization, immunofluorescence, and western blotting were conducted to test beige adipocyte activation in mice. X9 cells were induced with induction medium and maintenance medium containing 400 μg/mL of JLD. After completion of induction, cells were analyzed by Nile red staining, time polymerase chain reaction (PCR), western blotting, and immunofluorescence to understand the effect of JLD on the activation of beige adipocytes. A molecular docking method was used to preliminarily identify compounds in JLD, which hold the potential activation effect on uncoupling protein 1 (UCP1). JLD treatment significantly improved obesity in db/db mice. Biochemical results showed that JLD reduced blood glucose (GLU), triglyceride (TG), and low-density lipoprotein cholesterol (LDL) levels as well as liver aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in mice. Hematoxylin and eosin staining (H&E) showed that JLD reduced hepatocyte ballooning changes in the liver. Immunofluorescence showed that JLD increased the expression of the thermogenic protein, UCP1, in the beige adipose tissue of mice. JLD also increased the expression of UCP1 and inhibited the expression of miR-27a in X9 cells. Molecular docking results showed that epmedin B, epmedin C, icariin, puerarin, and salvianolic acid B had potential activation effects on UCP1. The results suggest that JLD may activate beige adipocytes by inhibiting miR-27a expression, thereby promoting thermogenesis in beige adipocytes. This study provides a new pharmacological basis for the clinical use of JLD.

Leptin Signaling in Obesity and Colorectal Cancer

Obesity and colorectal cancer (CRC) are among the leading diseases causing deaths in the world, showing a complex multifactorial pathology. Obesity is considered a risk factor in CRC development through inflammation, metabolic, and signaling processes. Leptin is one of the most important adipokines related to obesity and an important proinflammatory marker, mainly expressed in adipose tissue, with many genetic variation profiles, many related influencing factors, and various functions that have been ascribed but not yet fully understood and elucidated, the most important ones being related to energy metabolism, as well as endocrine and immune systems. Aberrant signaling and genetic variations of leptin are correlated with obesity and CRC, with the genetic causality showing both inherited and acquired events, in addition to lifestyle and environmental risk factors; these might also be related to specific pathogenic pathways at different time points. Moreover, mutation gain is a crucial factor enabling the genetic process of CRC. Currently, the inconsistent and insufficient data related to leptin's relationship with obesity and CRC indicate the necessity of further related studies. This review summarizes the current knowledge on leptin genetics and its potential relationship with the main pathogenic pathways of obesity and CRC, in an attempt to understand the molecular mechanisms of these associations, in the context of inconsistent and contradictory data. The understanding of these mechanisms linking obesity and CRC could help to develop novel therapeutic targets and prevention strategies, resulting in a better prognosis and management of these diseases.

Respiratory diseases and obesity: special phenotype or independent events: Review

A combination of factors, including Western European eating habits, physical inactivity and genetic predisposition, lead to a dramatic increase in adipose tissue mass. A special place is occupied by abdominal obesity, in which there is an accumulation of adipose tissue in the mesentery of the small intestine and the omentum. Developing in conditions of visceral obesity, insulin resistance, dyslipidemia and systemic inflammation are one of the key components of the pathogenesis of type 2 diabetes mellitus, cardiovascular diseases, non-alcoholic fatty liver and pancreas disease, polycystic ovary disease, some forms of cancer (breast cancer, endometrial cancer, colonic and direct intestines). At the same time, the pathogenetic role of adipose tissue is not limited to its participation in the formation of the cardiometabolic continuum and oncogenesis. The most important role of metabolically active fat in the pathogenesis of many respiratory diseases is known, including bronchial asthma, obstructive sleep apnea and pulmonary hypertension. This paper presents an overview of current data on immunological, pathophysiological and clinical features of the phenotype of the combination of respiratory diseases with overweight and obesity.

Anti-inflammatory effect of a triterpenoid from Balanophora laxiflora: results of bioactivity-guided isolation

Balanophora laxiflora, a medicinal plant traditionally used to treat fever, pain, and inflammation in Vietnam, has been reported to possess prominent anti-inflammatory activity. This study examined the active constituents and molecular mechanisms underlying these anti-inflammatory effects using bioactivity-guided isolation in combination with cell-based assays and animal models of inflammation. Among the isolated compounds, the triterpenoid (21α)-22-hydroxyhopan-3-one (1) showed the most potent inhibitory effect on COX-2 expression in LPS-stimulated Raw 264.7 macrophages. Furthermore, 1 suppressed the expression of the inflammatory mediators iNOS, IL-1β, INFβ, and TNFα in activated Raw 264.7 macrophages and alleviated the inflammatory response in carrageenan-induced paw oedema and a cotton pellet-induced granuloma model. Mechanistically, the anti-inflammatory effects of 1 were mediated via decreasing cellular reactive oxygen species (ROS) levels by inhibiting NADPH oxidases (NOXs) and free radical scavenging activities. By downregulating ROS signalling, 1 reduced the activation of MAPK signalling pathways, leading to decreased AP-1-dependent transcription of inflammatory mediators. These findings shed light on the chemical constituents that contribute to the anti-inflammatory actions of B. laxiflora and suggest that 1 is a promising candidate for treating inflammation-related diseases.

Bisphenol F suppresses insulin-stimulated glucose metabolism in adipocytes by inhibiting IRS-1/PI3K/AKT pathway

Obesity is one of the risk factors of metabolic diseases. Decreased sensitivity to insulin or impairment of the insulin signaling pathway may affect the metabolism of adipose tissue. Bisphenol F (BPF) has been widely used in various products as a substitute for bisphenol A (BPA). BPA has been defined as "obesogen". However, knowledge about the correlation between BPF and obesity is very limited. This study was aimed to explore the effects of BPF on glucose metabolism and insulin sensitivity in mammalian tissues, using a mouse 3T3-L1 adipocyte line as the model. Differentiated 3T3-L1 adipocytes were treated with BPF at various concentrations for 24 h or 48 h, followed by the measurement of cell viability, lipid accumulation, expression levels of adipocytokines, glucose consumption, and impairment of the insulin signaling pathway. The results indicated that BPF had no effect on the size of 3T3-L1 adipocytes, but the expression of leptin, adiponectin and apelin was decreased, while that of chemerin and resistin was increased after 48 h of BPF treatment. Moreover, BPF inhibited the glucose consumption, the expression of GLUT4, and its translocation to the plasma membranes in 3T3-L1 adipocytes. Western blot analysis indicated that the activation of IRS-1/PI3K/AKT signaling pathway was inhibited by BPF, which resulted in reduced GLUT4 translocation. In conclusion, our data suggest that exposure of adipocytes to BPF may alter the expression of calorie metabolism-related adipokines and suppress insulin-stimulated glucose metabolism by impairing the insulin signaling (IRS-1/PI3K/AKT) pathway.

Adiponectin triggers breast cancer cell death via fatty acid metabolic reprogramming

Background

Adiponectin, the most abundant adipokine derived from adipose tissue, exhibits a potent suppressive effect on the growth of breast cancer cells; however, the underlying molecular mechanisms for this effect are not completely understood. Fatty acid metabolic reprogramming has recently been recognized as a crucial driver of cancer progression. Adiponectin demonstrates a wide range of metabolic activities for the modulation of lipid metabolism under physiological conditions. However, the biological actions of adiponectin in cancer-specific lipid metabolism and its role in the regulation of cancer cell growth remain elusive.

Methods

The effects of adiponectin on fatty acid metabolism were evaluated by measuring the cellular neutral lipid pool, free fatty acid level, and fatty acid oxidation (FAO). Colocalization between fluorescent-labeled lipid droplets and LC3/lysosomes was employed to detect lipophagy activation. Cell viability and apoptosis were examined by MTS assay, caspase-3/7 activity measurement, TUNEL assay, and Annexin V binding assay. Gene expression was determined by real time-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The transcriptional activity of SREBP-1 was examined by a specific dsDNA binding assay. The modulatory roles of SIRT-1 and adiponectin-activated mediators were confirmed by gene silencing and/or using their pharmacological inhibitors. Observations from in vitro assays were further validated in an MDA-MB-231 orthotopic breast tumor model.

Results

Globular adiponectin (gAcrp) prominently decreased the cellular lipid pool in different breast cancer cells. The cellular lipid deficiency promoted apoptosis by causing disruption of lipid rafts and blocking raft-associated signal transduction. Mechanistically, dysregulated cellular lipid homeostasis by adiponectin was induced by two concerted actions: 1) suppression of fatty acid synthesis (FAS) through downregulation of SREBP-1 and FAS-related enzymes, and 2) stimulation of lipophagy-mediated lipolysis and FAO. Notably, SIRT-1 induction critically contributed to the adiponectin-induced metabolic alterations. Finally, fatty acid metabolic remodeling by adiponectin and the key role of SIRT-1 were confirmed in nude mice bearing breast tumor xenografts.

Conclusion

This study elucidates the multifaceted role of adiponectin in tumor fatty acid metabolic reprogramming and provides evidence for the connection between its metabolic actions and suppression of breast cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02223-y.

Exercise Inhibits NLRP3 Inflammasome Activation in Obese Mice via the Anti-Inflammatory Effect of Meteorin-like

Obesity is associated with chronic low-grade inflammation. The benefits of exercise are partly attributed to its anti-inflammatory effect, but whether exercise can regulate NLRP3 inflammasome activation in obese adipose tissue remains unknown. Meteorin-like (METRNL), a recently discovered myokine, has been implicated in mediating the effect of exercise on metabolism. Herein, we examined the effect of exercise and METRNL on NLRP3 inflammasome activation. High-fat diet (HFD)-induced obese mice were subjected to treadmill exercise for 8 weeks. A subgroup of HFD mice was switched to normal chow with the exercise intervention. Exercise and diet attenuated weight gain, fat accumulation, and insulin resistance in obese mice. In addition, exercise downregulated gene and protein levels of inflammasome markers, including NLRP3 and caspase-1, in adipose tissue. In isolated bone marrow-derived macrophages, activation of NLRP3 inflammasome was suppressed in the exercise group, as confirmed by the downregulation of IL-1β and IL-18. Exercise significantly enhanced the expression of METRNL in various muscle depots, and further in vitro analysis revealed that recombinant METRNL treatment inhibited IL-1β secretion in macrophages. In conclusion, exercise exerts its anti-inflammatory action by suppressing adipose tissue NLRP3 inflammasome, and this is, in part, associated with METRNL induction in muscle and its anti-inflammatory effects in macrophages.

Leptin Induces Apoptotic and Pyroptotic Cell Death via NLRP3 Inflammasome Activation in Rat Hepatocytes

Leptin, a hormone that is predominantly produced by adipose tissue, is closely associated with various liver diseases. However, there is a lack of understanding as to whether leptin directly induces cytotoxic effects in hepatocytes as well as the mechanisms that are involved. Inflammasomes, which are critical components in the innate immune system, have been recently shown to modulate cell death. In this study, we examined the effect of leptin on the viability of rat hepatocytes and the underlying mechanisms, with a particular focus on the role of inflammasomes activation. Leptin treatment induced cytotoxicity in rat hepatocytes, as determined by decreased cell viability, increased caspase-3 activity, and the enhanced release of lactate dehydrogenase. NLRP3 inflammasomes were activated by leptin both in vitro and in vivo, as determined by the maturation of interleukin-1β and caspase-1, and the increased expression of inflammasome components, including NLRP3 and ASC. Mechanistically, leptin-induced inflammasome activation is mediated via the axis of ROS production, ER stress, and autophagy. Notably, the inhibition of inflammasomes by treatment with the NLRP3 inhibitor or the IL-1 receptor antagonist protected the hepatocytes from leptin-induced cell death. Together, these results indicate that leptin exerts cytotoxic effects in hepatocytes, at least in part, via the activation of NLRP3 inflammasomes.

Sestrin2 induction contributes to anti-inflammatory responses and cell survival by globular adiponectin in macrophages

Adiponectin, an adipose tissue-derived hormone, exhibits a modulatory effect on cell death/survival and possesses potent anti-inflammatory properties. However, the underlying molecular mechanisms remain elusive. Sestrin2, a stress-inducible metabolic protein, has shown cytoprotective and inflammation-modulatory effects under stressful conditions. In this study, we examined the role of sestrin2 signaling in the modulation of cell survival and inflammatory responses by globular adiponectin (gAcrp) in macrophages. We observed that gAcrp induced a significant increase in sestrin2 expression in both RAW 264.7 murine macrophages and primary murine macrophages. Notably, gAcrp treatment markedly increased expression of hypoxia inducible factor-1 α (HIF-1α) and gene silencing of HIF-1α blocked sestrin2 induction by gAcrp. In addition, pretreatment with a pharmacological inhibitor of ERK or PI3K abrogated both sestrin2 and HIF-1α expression by gAcrp, indicating that ERK/PI3K-mediated HIF-1α signaling pathway plays a critical role in sestrin2 induction by gAcrp. Furthermore, sestrin2 induction is implicated in autophagy activation, and knockdown of sestrin2 prevented enhanced cell viability by gAcrp. Moreover, gene silencing of sestrin2 caused restoration of gAcrp-induced expression of anti-inflammatory genes in a gene-selective manner. Taken together, these results indicate that sestrin2 induction critically contributes to cell survival and anti-inflammatory responses by gAcrp in macrophages.

Effects of an interdisciplinary weight loss program on fibroblast growth factor 21 and inflammatory biomarkers in women with overweight and obesity

Objective

To investigate the effects of an interdisciplinary intervention on biomarkers of inflammation and their relationship with fibroblast growth factor 21 (FGF21) concentrations in women with overweight and obesity.

Methods

Thirty-one women were enrolled in a 12-week interdisciplinary weight loss program delivered by a team comprising an endocrinologist, nutritionist and exercise physiologist. Body composition; anthropometric measures; metabolic and inflammatory markers including adiponectin, leptin, and atrial natriuretic peptide (ANP) were assessed at baseline and post-therapy. The homeostasis model assessment of insulin resistance (HOMA-IR) and the homeostasis model assessment of adiponectin (HOMA-AD) were calculated. The participants were divided into two groups: those with increased FGF21, and those with decreased FGF21.

Results

The sample comprised women aged 32 ± 5 years with a body mass index of 33.64 ± 3.49 kg/m². Body weight, waist circumference and leptin concentration were decreased in the whole sample after therapy. However, only the group with an increase in FGF21 concentration presented significant improvements in adiponectin concentration and adiponectin/leptin ratio. Moreover, although there was a reduction of leptin in both groups, it was greater in the increased FGF21 groups. There was a reduction in ANP in the decreased FGF21 group.

Conclusion

Changes in FGF21 concentrations were different among the women participating in the weight loss program, with some having increased levels and some reduced levels. Furthermore, improvements in adiponectin and the adiponectin/leptin ratio were found only in the group with increased FGF21 concentration.

Obesity-associated cardiovascular risk in women: hypertension and heart failure

The pathogenesis of obesity-associated cardiovascular diseases begins long prior to the presentation of a cardiovascular event. In both men and women, cardiovascular events, and their associated hospitalizations and mortality, are often clinically predisposed by the presentation of a chronic cardiovascular risk factor. Obesity increases the risk of cardiovascular diseases in both sexes, however, the clinical prevalence of obesity, as well as its contribution to crucial cardiovascular risk factors is dependent on sex. The mechanisms via which obesity leads to cardiovascular risk is also discrepant in women between their premenopausal, pregnancy and postmenopausal phases of life. Emerging data indicate that at all reproductive statuses and ages, the presentation of a cardiovascular event in obese women is strongly associated with hypertension and its subsequent chronic risk factor, heart failure with preserved ejection fraction (HFpEF). In addition, emerging evidence indicates that obesity increases the risk of both hypertension and heart failure in pregnancy. This review will summarize clinical and experimental data on the female-specific prevalence and mechanisms of hypertension and heart failure in women across reproductive stages and highlight the particular risks in pregnancy as well as emerging data in a high-risk ethnicity in women of African ancestry (AA).

Polycystic ovary syndrome: Pathways and mechanisms for possible increased susceptibility to COVID-19

In 75% of women with polycystic ovary syndrome (PCOS), insulin action is impaired. In obesity, visceral adipose tissue becomes dysfunctional: Chronic inflammation is favored over storage, contributing to the development of metabolic complications. PCOS, metabolic syndrome (MetSy) and non-alcoholic fatty liver disease (NAFLD) apparently share common pathogenic factors; these include abdominal adiposity, excess body weight and insulin resistance. Alterations in the gut microbiome have been noted in women with PCOS compared to controls; these may lead to deterioration of the intestinal barrier, increased gut mucosal permeability and immune system activation, hyperinsulinemia and glucose intolerance, which hamper normal ovarian function and follicular development (all being hallmarks of PCOS). It has been proposed that PCOS may entail higher susceptibility to coronavirus disease 2019 (COVID-19) via its associated comorbidities (NAFLD, obesity, MetSy and alterations in the gut microbiome). Studies have found an association between acute respiratory distress syndrome (seen in severe cases of COVID-19) and the intestinal microbiome. Furthermore, apparently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can gain entry to the gastrointestinal tract via locally-expressed angiotensin converting enzyme type 2 receptors. Excess body weight is associated with more severe COVID-19 and increased mortality. Although robust links between SARS-CoV-2 infection and PCOS/NAFLD/gut microbiome/metabolic consequences are yet to be confirmed, it seems that strategies for adapting the intestinal microbiome could help reduce the severity of COVID-19 in women with PCOS with or without NAFLD, MetSy or obesity.

The role of immune dysfunction in obesity-associated cancer risk, progression, and metastasis

Obesity has been linked to an increased risk of and a worse prognosis for several types of cancer. A number of interrelated mediators contribute to obesity's pro-tumor effects, including chronic adipose inflammation and other perturbations of immune cell development and function. Here, we review studies examining the impact of obesity-induced immune dysfunction on cancer risk and progression. While the role of adipose tissue inflammation in obesity-associated cancer risk has been well characterized, the effects of obesity on immune cell infiltration and activity within the tumor microenvironment are not well studied. In this review, we aim to highlight the impact of both adipose-mediated inflammatory signaling and intratumoral immunosuppressive signaling in obesity-induced cancer risk, progression, and metastasis.

Leptin and Cancer: Updated Functional Roles in Carcinogenesis, Therapeutic Niches, and Developments

Leptin is an obesity-associated adipokine that is known to regulate energy metabolism and reproduction and to control appetite via the leptin receptor. Recent work has identified specific cell types other than adipocytes that harbor leptin and leptin receptor expression, particularly in cancers and tumor microenvironments, and characterized the role of this signaling axis in cancer progression. Furthermore, the prognostic significance of leptin in various types of cancer and the ability to noninvasively detect leptin levels in serum samples have attracted attention for potential clinical applications. Emerging findings have demonstrated the direct and indirect biological effects of leptin in regulating cancer proliferation, metastasis, angiogenesis and chemoresistance, warranting the exploration of the underlying molecular mechanisms to develop a novel therapeutic strategy. In this review article, we summarize and integrate transcriptome and clinical data from cancer patients together with the recent findings related to the leptin signaling axis in the aforementioned malignant phenotypes. In addition, a comprehensive analysis of leptin and leptin receptor distribution in a pancancer panel and in individual cell types of specific organs at the single-cell level is presented, identifying those sites that are prone to leptin-mediated tumorigenesis. Our results shed light on the role of leptin in cancer and provide guidance and potential directions for further research for scientists in this field.

Impact of Dietary Flavanols on Microbiota, Immunity and Inflammation in Metabolic Diseases

Flavanols are natural occurring polyphenols abundant in fruits and vegetables to which have been attributed to beneficial effects on health, and also against metabolic diseases, such as diabetes, obesity and metabolic syndrome. These positive properties have been associated to the modulation of different molecular pathways, and importantly, to the regulation of immunological reactions (pro-inflammatory cytokines, chemokines, adhesion molecules, nuclear factor-κB [NF-κB], inducible enzymes), and the activity of cells of the immune system. In addition, flavanols can modulate the composition and function of gut microbiome in a prebiotic-like manner, resulting in the positive regulation of metabolic pathways and immune responses, and reduction of low-grade chronic inflammation. Moreover, the biotransformation of flavanols by gut bacteria increases their bioavailability generating a number of metabolites with potential to affect human metabolism, including during metabolic diseases. However, the exact mechanisms by which flavanols act on the microbiota and immune system to influence health and disease remain unclear, especially in humans where these connections have been scarcely explored. This review seeks to summarize recent advances on the complex interaction of flavanols with gut microbiota, immunity and inflammation focus on metabolic diseases.

Tumor Metabolic Reprogramming by Adipokines as a Critical Driver of Obesity-Associated Cancer Progression

Adiposity is associated with an increased risk of various types of carcinoma. One of the plausible mechanisms underlying the tumor-promoting role of obesity is an aberrant secretion of adipokines, a group of hormones secreted from adipose tissue, which have exhibited both oncogenic and tumor-suppressing properties in an adipokine type- and context-dependent manner. Increasing evidence has indicated that these adipose tissue-derived hormones differentially modulate cancer cell-specific metabolism. Some adipokines, such as leptin, resistin, and visfatin, which are overproduced in obesity and widely implicated in different stages of cancer, promote cellular glucose and lipid metabolism. Conversely, adiponectin, an adipokine possessing potent anti-tumor activities, is linked to a more favorable metabolic phenotype. Adipokines may also play a pivotal role under the reciprocal regulation of metabolic rewiring of cancer cells in tumor microenvironment. Given the fact that metabolic reprogramming is one of the major hallmarks of cancer, understanding the modulatory effects of adipokines on alterations in cancer cell metabolism would provide insight into the crosstalk between obesity, adipokines, and tumorigenesis. In this review, we summarize recent insights into putative roles of adipokines as mediators of cellular metabolic rewiring in obesity-associated tumors, which plays a crucial role in determining the fate of tumor cells.

Fibroblast growth factor 2 exacerbates inflammation in adipocytes through NLRP3 inflammasome activation

Chronic inflammation in adipose tissue is the hallmark of obesity and a major risk factor for the development of obesity-induced insulin resistance. NLRP3 inflammasome regulates the maturation and secretion of pro-inflammatory cytokines, such as IL-1β and IL-18, and was recently discovered to be involved in obesity-related metabolic diseases. Fibroblast growth factors (FGFs) such as FGF1, FGF10, and FGF21 are adipokines that regulate adipocyte development and metabolism, but reports on the effect of other FGFs on adipocytes are lacking. In the present study, the novel role of FGF2 in NLRP3 inflammasome activation was elucidated. Our results showed that FGF2 levels were increased during adipocyte differentiation and in the adipose tissue of high-fat diet (HFD)-induced obese mice. Recombinant FGF2 treatment upregulated inflammasome markers such as NLRP3, which was further exaggerated by TNF-ɑ treatment. Interestingly, β-Klotho, a co-receptor of FGF21, was significantly decreased by FGF2 treatment. Results from mice confirmed the positive correlation between FGF2 and NLRP3 expression in epididymal and subcutaneous adipose tissue, while exercise training effectively reversed HFD-induced NLRP3 expression as well as FGF2 levels in both adipose depots. Our results suggest that FGF2 is an adipokine that may exacerbate the inflammatory response in adipocytes through NLRP3 inflammasome activation.

Nasser S, Younis N, Bhagani H, Al-Dhaheri Y, Pintus G, Eid AA, El-Yazbi AF, Eid AH. Visfatin: A Possible Role in Cardiovasculo-Metabolic Disorders

Visfatin/NAMPT (nicotinamide phosphoribosyltransferase) is an adipocytokine with several intriguing properties. It was first identified as pre-B-cell colony-enhancing factor but turned out to possess enzymatic functions in nicotinamide adenine dinucleotide biosynthesis, with ubiquitous expression in skeletal muscles, liver, cardiomyocytes, and brain cells. Visfatin exists in an intracellular (iNAMPT) and extracellular (eNAMPT) form. Intracellularly, visfatin/iNAMPT plays a regulatory role in NAD⁺ biosynthesis and thereby affects many NAD-dependent proteins such as sirtuins, PARPs, MARTs and CD38/157. Extracellularly, visfatin is associated with many hormone-like signaling pathways and activates some intracellular signaling cascades. Importantly, eNAMPT has been associated with several metabolic disorders including obesity and type 1 and 2 diabetes. In this review, a brief overview about visfatin is presented with special emphasis on its relevance to metabolic diseases. Visfatin/NAMPT appears to be a unique molecule with clinical significance with a prospective promising diagnostic, prognostic, and therapeutic applications in many cardiovasculo-metabolic disorders.