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Background We developed clinically relevant genotypic scores for resistance to fosamprenavir/ritonavir in HIV-1 protease inhibitor (PI)-experienced patients. Methods PI-experienced patients with virological failure receiving fosamprenavir/ritonavir as the sole PI for at least 3 months and with detectable fosamprenavir plasma levels were included. The impact of baseline protease mutations on virological response (VR, i.e. decrease in plasma HIV-1 RNA between baseline and month 3) was analysed using the Mann–Whitney test. Mutations with prevalence >10% and P value Results In the 73 patients included, the median baseline HIV-1 RNA was 4.6 log10 copies/mL (range: 2.7–6.9) and the mean decrease at month 3 was −1.07 ± 1.40 log10 copies/mL. Ninety per cent of the patients were infected by HIV-1 subtype B variants. Two fosamprenavir/ritonavir mutation scores were constructed: score A (L10F/I/V + L33F + M36I + I54L/M/V/A/T/S + I62V + V82A/F/C/G + I84V + L90M) was based only on mutations associated with a worse VR, whereas score B (L10FIV + L33F + M36I + I54L/M/V/A/T/S + A71V − V77I − N88S + L90M) also took into account favourable mutations. Both scores were independent predictors of VR, however, co-administration of tenofovir was associated with a worse VR and the presence of the N88S protease mutation and co-administration of enfuvirtide with a better VR. Conclusions These clinically validated mutation scores should be of interest for the clinical management of PI-experienced patients. The fosamprenavir/ritonavir score A was introduced in the 2006 ANRS algorithm along with isolated mutations I50V and V32I + I47V. [ABSTRACT FROM AUTHOR]

The goal of this study is to test a novel device and methodology based on the "Pebble" platform and real-time quantitative colorimetric loop-mediated isothermal amplification (qcLAMP) during SARS-CoV-2 detection using crude samples and extracted RNA. The new method employs an inexpensive lightweight device aimed toward rapid point-of-care testing. An extensive evaluation was performed consisting of 1,693 clinical samples across five independent clinical testing centers. Positive colorimetric results were observed within 20 minutes of testing. At a 20-minute time-to-positive cut-off, the specificity is 98.5% with a diagnostic accuracy of 91.9%, compared to qPCR assays. Our findings indicate that the SARS-CoV-2 qcLAMP diagnostic assay in conjunction with the Pebble device is ideal for point-of-care/near-patient testing.IMPORTANCEHere, we describe our analyses and validation of a novel real-time quantitative colorimetric loop-mediated isothermal amplification (qcLAMP) device, available under the name "Pebble" and associated SARS-CoV-2 diagnostic qcLAMP assay for clinical diagnostic use. The analyses were performed in five independent testing sites across Europe using clinical samples from the associated clinical sites and support the use of "pebble" and associated kit in the diagnostic environment.

Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic virus involved in several diseases. The gold standard for KSHV sero diagnosis remains the indirect immunofluorescence assay (IFA), which is time-consuming and operator-dependent. We compared this method with an enzyme-linked immunosorbent assay (ELISA) targeting solubilized KSHV whole-genome extract among positive ( n = 49, including 76% of HIV-infected patients) and negative ( n = 14) control groups. We also included 14 sera with equivocal IFA results. ELISA showed better performance in detecting KSHV antibodies (McNemar's test, P = 0.0455). The sensitivity and specificity of both methods were 79% (64-89) and 100% (66-100) for the IFA, respectively, and 94% (83-99) and 100% (66-100) for ELISA, respectively. All IFA equivocal results were either negative or positive with ELISA. ELISA is more reliable and could be a good alternative for determining KSHV serological status, particularly in the context of immunocompromised patients and equivocal serology with the IFA.IMPORTANCEKaposi's sarcoma-associated herpesvirus (KSHV) sero status remains challenging because no perfect reference is available for the detection of KSHV antibodies. The current gold-standard method, the indirect immunofluorescence assay (IFA), has a very good specificity of close to 100%, but a lower sensitivity of around 80-85%, which decreases to 64-67% in immunocompromised patients. Additionally, this method is time-consuming and operator-dependent compared with new serological assays such as the enzyme-linked immunosorbent assay (ELISA). Thus, further research is still needed to improve KSHV sero diagnosis. Here, we compare the KSHV IgG ELISA kit assay (Advanced Biotechnologies Inc) with the gold-standard IFA, targeting the LANA-1 protein from latent BC-3 cell lines.

Background/objectives: Proinflammatory cytokines are increased in obese adipose tissue, including inflammasome key masters. Conversely, IL-18 protects against obesity and metabolic dysfunction. We focused on the IL-18 effect in controlling adipose tissue remodeling and metabolism., Materials/subjects and Methods: We used C57BL/6 wild-type (WT) and interleukine-18 deficient (IL-18 -/- ) male mice fed a chow diet and samples from bariatric surgery patients., Results: IL-18 -/- mice showed increased adiposity and proinflammatory cytokine levels in adipose tissue, leading to glucose intolerance. IL-18 was widely secreted by stromal vascular fraction but not adipocytes from mice's fatty tissue. Chimeric model experiments indicated that IL-18 controls adipose tissue expansion through its presence in tissues other than bone marrow. However, IL-18 maintains glucose homeostasis when present in bone marrow cells. In humans with obesity, IL-18 expression in omental tissue was not correlated with BMI or body fat mass but negatively correlated with IRS1, GLUT-4, adiponectin, and PPARy expression. Also, the IL-18RAP receptor was negatively correlated with IL-18 expression., Conclusions: IL-18 signaling may control adipose tissue expansion and glucose metabolism, as its absence leads to spontaneous obesity and glucose intolerance in mice. We suggest that resistance to IL-18 signaling may be linked with worse glucose metabolism in humans with obesity., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Glutamine and glutamate are interconverted by several enzymes and alterations in this metabolic cycle are linked to cardiometabolic traits. Herein, we show that obesity-associated insulin resistance is characterized by decreased plasma and white adipose tissue glutamine-to-glutamate ratios. We couple these stoichiometric changes to perturbed fat cell glutaminase and glutamine synthase messenger RNA and protein abundance, which together promote glutaminolysis. In human white adipocytes, reductions in glutaminase activity promote aerobic glycolysis and mitochondrial oxidative capacity via increases in hypoxia-inducible factor 1α abundance, lactate levels and p38 mitogen-activated protein kinase signalling. Systemic glutaminase inhibition in male and female mice, or genetically in adipocytes of male mice, triggers the activation of thermogenic gene programs in inguinal adipocytes. Consequently, the knockout mice display higher energy expenditure and improved glucose tolerance compared to control littermates, even under high-fat diet conditions. Altogether, our findings highlight white adipocyte glutamine turnover as an important determinant of energy expenditure and metabolic health., (© 2024. The Author(s).)

Diet composition impacts metabolic health and is now recognized to shape the immune system, especially in the intestinal tract. Nutritional imbalance and increased caloric intake are induced by high-fat diet (HFD) in which lipids are enriched at the expense of dietary fibers. Such nutritional challenge alters glucose homeostasis as well as intestinal immunity. Here, we observed that short-term HFD induced dysbiosis, glucose intolerance and decreased intestinal RORγt + CD4 T cells, including peripherally-induced Tregs and IL17-producing (Th17) T cells. However, supplementation of HFD-fed male mice with the fermentable dietary fiber fructooligosaccharides (FOS) was sufficient to maintain RORγt + CD4 T cell subsets and microbial species known to induce them, alongside having a beneficial impact on glucose tolerance. FOS-mediated normalization of Th17 cells and amelioration of glucose handling required the cDC2 dendritic cell subset in HFD-fed animals, while IL-17 neutralization limited FOS impact on glucose tolerance. Overall, we uncover a pivotal role of cDC2 in the control of the immune and metabolic effects of FOS in the context of HFD feeding., (© 2024. The Author(s).)

This lecture delves into the pivotal role of adipose tissue in obesity and its response to weight loss, particularly via bariatric surgery. Adipose tissue, responsible for storing excess energy, undergoes significant changes during obesity, marked by inflammation and fibrosis. Bariatric surgery, serving as a model, allow the exploration of adipose tissue remodeling post-weight loss, inducing metabolic and fibro-inflammatory shifts. Despite successful weight loss, inflammation and fibrosis persist, as evidenced by changes in immune cells, altered cytokine profiles and the accumulation of extracellular matrix (ECM). Unfortunately, these lingering effects impair the normal adipose tissue function. In this context, adipose progenitors, an heterogenous resident population of mesenchymal stromal cells, display functions important to fibrosis development, capable of differentiating into myofibroblasts and contributing to ECM deposition. Particularly, a distinct subpopulation of adipose progenitors with high CD9 expression (CD9high) is associated with fibrosis and insulin resistance in human obesity. The persistence of fibrosis post-weight loss poses challenges, correlating with metabolic dysfunction despite improved glucose tolerance. A comprehensive understanding of the mechanisms driving adipose tissue remodeling and fibrosis post-weight loss is imperative for the development of effective treatments for obesity. The intricate interplay between adipose tissue, inflammation, and fibrosis underscores the necessity for further in-depth research to elucidate these mechanisms and formulate targeted therapies for obesity-related complications., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Background: Eosinophils are generally related to helminth infections or allergies. Their association with metabolic alterations and adipose tissue (AT) remodeling has been demonstrated mainly in animal models of obesity. However, their physiological role in driving metabolic features has not yet been well described. Herein, we aimed to evaluate the participation of eosinophils in metabolic and adipose tissue homeostasis in mice and humans, focusing on a translational perspective., Material and Methods: Male BALB/c wild-type (WT) mice and GATA-1 knockout (Δdb/GATA-1 -/- ) mice were followed until 16-week-age in a regular diet or were fed with a high-refined-carbohydrate (HC) diet or high-fat (HF) diet for eight weeks. In subjects with obesity, clinical parameters and omental AT gene expression were evaluated., Results: Eosinophils lack in mice fed a regular diet induced insulin resistance and increased adiposity. Their adipose tissue showed augmented cytokine levels, which could be attributed to increased leukocytes in the tissue, such as neutrophils and pro-inflammatory macrophages. Bone marrow transplant from WT mice to Δdb/GATA-1 -/- mice showed some improvement in glucose metabolism with lower adipose tissue mass accretion. Upon an unhealthy diet challenge, Δdb/GATA-1 -/- mice fed HC diet showed a mild degree of adiposity and glucose metabolic dysfunction severe in those mice fed HF diet. The expression of eosinophil markers in omental AT from humans with severe obesity was positively correlated to eosinophil cytokines and insulin sensitivity surrogate markers and negatively correlated to systemic insulin, HOMA-IR, and android fat mass., Conclusions: Eosinophils seem to have a physiological role by controlling systemic and adipose tissue metabolic homeostasis by modulating glucose metabolism, inflammation, and visceral fat expansion, even in lean mice. Indeed, eosinophils also seem to modulate glucose homeostasis in human obesity., Competing Interests: Declaration of competing interest None., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Obesity and type 2 diabetes (T2D) have been found to be associated with abnormalities in several organs, including the intestine. These conditions can lead to changes in gut homeostasis, compromising tolerance to luminal antigens and increasing susceptibility to food allergies. The underlying mechanisms for this phenomenon are not yet fully understood. In this study, we investigated changes in the intestinal mucosa of diet-induced obese mice and found that they exhibited increased gut permeability and reduced Treg cells frequency. Upon oral treatment with ovalbumin (OVA), obese mice failed to develop oral tolerance. However, hyperglycemia treatment improved intestinal permeability and oral tolerance induction in mice. Furthermore, we observed that obese mice exhibited a more severe food allergy to OVA, and this allergy was alleviated after treatment with a hypoglycemic drug. Importantly, our findings were translated to obese humans. Individuals with T2D had higher serum IgE levels and downregulated genes related to gut homeostasis. Taken together, our results suggest that obesity-induced hyperglycemia can lead to a failure in oral tolerance and to exacerbation of food allergy. These findings shed light on the mechanisms underlying the relationship among obesity, T2D, and gut mucosal immunity, which could inform the development of new therapeutic approaches., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Obesity is a chronic and progressive process affecting whole-body energy balance and is associated with comorbidity development. In addition to increased fat mass, obesity induces white adipose tissue (WAT) inflammation and fibrosis, leading to local and systemic metabolic dysfunctions, such as insulin resistance (IR). Accordingly, limiting inflammation or fibrosis deposition may improve IR and glucose homeostasis. Although no targeted therapy yet exists to slow or reverse adipose tissue fibrosis, a number of findings have clarified the underlying cellular and molecular mechanisms. In this review, we highlight adipose tissue remodeling events shown to be associated with fibrosis deposition, with a focus on adipose progenitors involved in obesity-induced healthy as well as unhealthy WAT expansion.

Background/objectives: Platelet-activating factor receptor (PAFR) activation controls adipose tissue (AT) expansion in animal models. Our objective was twofold: (i) to check whether PAFR signaling is involved in human obesity and (ii) investigate the PAF pathway role in hematopoietic or non-hematopoietic cells to control adipocyte size., Materials/subjects and Methods: Clinical parameters and adipose tissue gene expression were evaluated in subjects with obesity. Bone marrow (BM) transplantation from wild-type (WT) or PAFR -/- mice was performed to obtain chimeric PAFR-deficient mice predominantly in hematopoietic or non-hematopoietic-derived cells. A high carbohydrate diet (HC) was used to induce AT remodeling and evaluate in which cell compartment PAFR signaling modulates it. Also, 3T3-L1 cells were treated with PAF to evaluate fat accumulation and the expression of genes related to it., Results: PAFR expression in omental AT from humans with obesity was negatively correlated to different corpulence parameters and more expressed in the stromal vascular fraction than adipocytes. Total PAFR -/- increased adiposity compared with WT independent of diet-induced obesity. Differently, WT mice receiving PAFR -/- -BM exhibited similar adiposity gain as WT chimeras. PAFR -/- mice receiving WT-BM showed comparable augmentation in adiposity as total PAFR -/- mice, demonstrating that PAFR signaling modulates adipose tissue expansion through non-hematopoietic cells. Indeed, the PAF treatment in 3T3-L1 adipocytes reduced fat accumulation and expression of adipogenic genes., Conclusions: Therefore, decreased PAFR signaling may favor an AT accumulation in humans and animal models. Importantly, PAFR signaling, mainly in non-hematopoietic cells, especially in adipocytes, appears to play a significant role in regulating diet-induced AT expansion., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Roux-en-Y gastric bypass (RYGB) is efficient at inducing drastic albeit variable weight loss and type-2 diabetes (T2D) improvements in patients with severe obesity and T2D. We hypothesized a causal implication of the gut microbiota (GM) in these metabolic benefits, as RYGB is known to deeply impact its composition. In a cohort of 100 patients with baseline T2D who underwent RYGB and were followed for 5-years, we used a hierarchical clustering approach to stratify subjects based on the severity of their T2D (Severe vs Mild) throughout the follow-up. We identified via nanopore-based GM sequencing that the more severe cases of unresolved T2D were associated with a major increase of the class Bacteroidia, including 12 species comprising Phocaeicola dorei, Bacteroides fragilis , and Bacteroides caecimuris . A key observation is that patients who underwent major metabolic improvements do not harbor this enrichment in Bacteroidia, as those who presented mild cases of T2D at all times. In a separate group of 36 patients with similar baseline clinical characteristics and preoperative GM sequencing, we showed that this increase in Bacteroidia was already present at baseline in the most severe cases of T2D. To explore the causal relationship linking this enrichment in Bacteroidia and metabolic alterations, we selected 13 patients across T2D severity clusters at 5-years and performed fecal matter transplants in mice. Our results show that 14 weeks after the transplantations, mice colonized with the GM of Severe donors have impaired glucose tolerance and insulin sensitivity as compared to Mild-recipients, all in the absence of any difference in body weight and composition. GM sequencing of the recipient animals revealed that the hallmark T2D-severity associated bacterial features were transferred and were associated with the animals' metabolic alterations. Therefore, our results further establish the GM as a key contributor to long-term glucose metabolism improvements (or lack thereof) after RYGB.

While obesity is defined as an excessive fat accumulation conferring a risk to metabolic health, increased adipose mass by itself does not fully explain obesity's propensity to promote metabolic alterations. Adipose tissue regulates multiple processes critical for energy homeostasis and its dysfunction favors the development and perpetuation of metabolic diseases. Obesity drives inflammatory leucocyte infiltration in adipose tissue and fibrotic transformation of the fat depots. Both features associate with metabolic alterations such as impaired glucose control and resistance to fat mass loss. In this context, adipose progenitors, an heterogenous resident population of mesenchymal stromal cells, display functions important to shape healthy or unhealthy adipose tissue expansion. We, here, outline the current understanding of adipose progenitor biology in the context of obesity-induced adipose tissue remodeling., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In the context of obesity, senescent cells accumulate in white adipose tissue (WAT). The cellular underpinnings of WAT senescence leading to insulin resistance are not fully elucidated. The objective of the current study was to evaluate the presence of WAT senescence early after initiation of high-fat diet (HFD, 1-10 weeks) in 5-month-old male C57BL/6J mice and the potential role of energy metabolism. We first showed that WAT senescence occurred 2 weeks after HFD as evidenced in whole WAT by increased senescence-associated ß-galactosidase activity and cyclin-dependent kinase inhibitor 1A and 2A expression. WAT senescence affected various WAT cell populations, including preadipocytes, adipose tissue progenitors, and immune cells, together with adipocytes. WAT senescence was associated with higher glycolytic and mitochondrial activity leading to enhanced ATP content in HFD-derived preadipocytes, as compared with chow diet-derived preadipocytes. One-month daily exercise, introduced 5 weeks after HFD, was an effective senostatic strategy, since it reversed WAT cellular senescence, while reducing glycolysis and production of ATP. Interestingly, the beneficial effect of exercise was independent of body weight and fat mass loss. We demonstrated that WAT cellular senescence is one of the earliest events occurring after HFD initiation and is intimately linked to the metabolic state of the cells. Our data uncover a critical role for HFD-induced elevated ATP as a local danger signal inducing WAT senescence. Exercise exerts beneficial effects on adipose tissue bioenergetics in obesity, reversing cellular senescence, and metabolic abnormalities., (© 2021 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)

Aim/hypothesis: Altered adipose tissue secretory profile contributes to insulin resistance and type 2 diabetes in obesity. Preclinical studies have identified senescent cells as a cellular source of proinflammatory factors in adipose tissue of obese mice. In humans, potential links with obesity comorbidities are poorly defined. Here, we investigated adipose tissue senescent status and relationships with metabolic complications in human obesity., Methods: The study includes a prospective cohort of 227 individuals with severe obesity. A photometric method was used to quantify senescence-associated β-galactosidase (SA-β-gal) activity in paired subcutaneous and omental adipose tissue biopsies obtained during gastric surgery. Gene and secretory profiling was performed in adipose tissue biopsies and in human primary pre-adipocytes in the presence or absence of senolytic drugs targeting senescent cells. Participants were phenotyped for anthropometric and bioclinical variables, metabolic complications and gastric surgery-induced improvement to address relationships with adipose tissue SA-β-gal., Results: SA-β-gal activity was sevenfold higher in subcutaneous than in omental adipose tissue and not associated with BMI or chronological age. Several factors, including insulin-like growth factor binding protein 3 (IGFBP3), plasminogen activator inhibitor 1 (PAI1), C-C motif chemokine ligand 2 (CCL2) and IL-6, were upregulated in subcutaneous adipose tissue in relation with SA-β-gal (p for linear trend across tertiles <0.05) and in pre-adipocytes cultured with inflammatory macrophage conditioned media. Senolytic treatment reduced SA-β-gal staining and normalised these alterations. In the whole population, subcutaneous adipose tissue SA-β-gal activity was positively associated with serum leptin, markers of insulin resistance and increased trunk fat mass. Metabolic complications, including type 2 diabetes and dyslipidaemia, were more prevalent in patients with high levels of SA-β-gal, but improved with bariatric surgery whatever the initial adipose tissue senescent status., Conclusions/interpretation: This study highlights a phenotype of senescence in adipose tissue of severely obese individuals, which characterises prominently subcutaneous fat depots. Subcutaneous adipose tissue senescence is significantly linked to altered glucose metabolism and body fat distribution. Elimination of senescent cells through senolytic treatment could alleviate metabolic complications in severely obese people. Graphical abstract.

Adipose tissue (AT) fibrosis in obesity compromises adipocyte functions and responses to intervention-induced weight loss. It is driven by AT progenitors with dual fibro/adipogenic potential, but pro-fibrogenic pathways activated in obesity remain to be deciphered. To investigate the role of macroautophagy/autophagy in AT fibrogenesis, we used Pdgfra-Cre Ert2 transgenic mice to create conditional deletion of Atg7 alleles in AT progenitor cells ( atg7 cKO) and examined sex-dependent, depot-specific AT remodeling in high-fat diet (HFD)-fed mice. Mice with atg7 cKO had markedly decreased extracellular matrix (ECM) gene expression in visceral, subcutaneous, and epicardial adipose depots compared to Atg7 lox/lox littermates. ECM gene program regulation by autophagy inhibition occurred independently of changes in the mass of fat tissues or adipocyte numbers of specific depots, and cultured preadipocytes treated with pharmacological or siRNA-mediated autophagy disruptors could mimic these effects. We found that autophagy inhibition promotes global cell-autonomous remodeling of the paracrine TGF-BMP family landscape, whereas ECM gene modulation was independent of the autophagic regulation of GTF2IRD1. The progenitor-specific mouse model of ATG7 inhibition confirms the requirement of autophagy for white/beige adipocyte turnover, and combined to in vitro experiments, reveal progenitor autophagy dependence for AT fibrogenic response to HFD, through the paracrine remodeling of TGF-BMP factors balance. Abbreviations: CQ: chloroquine; ECM: extracellular matrix; EpiAT: epididymal adipose tissue; GTF2IRD1: general transcription factor II I repeat domain-containing 1; HFD: high-fat diet; KO: knockout; OvAT: ovarian adipose tissue; PDGFR: platelet derived growth factor receptor; ScAT: subcutaneous adipose tissue; TGF-BMP: transforming growth factor-bone morphogenic protein.

Kupffer cells (KCs) are liver-resident macrophages that self-renew by proliferation in the adult independently from monocytes. However, how they are maintained during non-alcoholic steatohepatitis (NASH) remains ill defined. We found that a fraction of KCs derived from Ly-6C + monocytes during NASH, underlying impaired KC self-renewal. Monocyte-derived KCs (MoKCs) gradually seeded the KC pool as disease progressed in a response to embryo-derived KC (EmKC) death. Those MoKCs were partly immature and exhibited a pro-inflammatory status compared to EmKCs. Yet, they engrafted the KC pool for the long term as they remained following disease regression while acquiring mature EmKC markers. While KCs as a whole favored hepatic triglyceride storage during NASH, EmKCs promoted it more efficiently than MoKCs, and the latter exacerbated liver damage, highlighting functional differences among KCs with different origins. Overall, our data reveal that KC homeostasis is impaired during NASH, altering the liver response to lipids, as well as KC ontogeny., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Obesity originates from an imbalance between caloric intake and energy expenditure that promotes adipose tissue expansion, which is necessary to buffer nutrient excess. Patients with higher visceral fat mass are at a higher risk of developing severe complications such as type 2 diabetes and cardiovascular and liver diseases. However, increased fat mass does not fully explain obesity's propensity to promote metabolic diseases. With chronic obesity, adipose tissue undergoes major remodeling, which can ultimately result in unresolved chronic inflammation leading to fibrosis accumulation. These features drive local tissue damage and initiate and/or maintain multiorgan dysfunction. Here, we review the current understanding of adipose tissue remodeling with a focus on obesity-induced adipose tissue fibrosis and its relevance to clinical manifestations.

Background: Aging induces cardiac structural and functional changes linked to the increased deposition of extracellular matrix proteins, including OPN (osteopontin), conducing to progressive interstitial fibrosis. Although OPN is involved in various pathological conditions, its role in myocardial aging remains unknown., Methods: OPN deficient mice (OPN-/-) with their wild-type (WT) littermates were evaluated at 2 and 14 months of age in terms of cardiac structure, function, histology and key molecular markers. OPN expression was determined by reverse-transcription polymerase chain reaction, immunoblot and immunofluorescence. Luminex assays were performed to screen plasma samples for various cytokines/adipokines in addition to OPN. Similar explorations were conducted in aged WT mice after surgical removal of visceral adipose tissue (VAT) or treatment with a small-molecule OPN inhibitor agelastatin A. Primary WT fibroblasts were incubated with plasma from aged WT and OPN-/- mice, and evaluated for senescence (senescence-associated β-galactosidase and p16), as well as fibroblast activation markers (Acta2 and Fn1)., Results: Plasma OPN levels increased in WT mice during aging, with VAT showing the strongest OPN induction contrasting with myocardium that did not express OPN. VAT removal in aged WT mice restored cardiac function and decreased myocardial fibrosis in addition to a substantial reduction of circulating OPN and transforming growth factor β levels. OPN deficiency provided a comparable protection against age-related cardiac fibrosis and dysfunction. Intriguingly, a strong induction of senescence in cardiac fibroblasts was observed in both VAT removal and OPN-/- mice. The addition of plasma from aged OPN-/- mice to cultures of primary cardiac fibroblasts induced senescence and reduced their activation (compared to aged WT plasma). Finally, Agelastatin A treatment of aged WT mice fully reversed age-related myocardial fibrosis and dysfunction., Conclusions: During aging, VAT represents the main source of OPN and alters heart structure and function via its profibrotic secretome. As a proof-of-concept, interventions targeting OPN, such as VAT removal and OPN deficiency, rescued the heart and induced a selective modulation of fibroblast senescence. Our work uncovers OPN's role in the context of myocardial aging and proposes OPN as a potential new therapeutic target for a healthy cardiac aging.

Objective: Bile acids have been implicated as important regulators of glucose metabolism via activation of FXR and GPBAR1. We have previously shown that FGF19 can modulate glucose handling by suppressing the activity of hypothalamic AGRP/NPY neurons. As bile acids stimulate the release of FGF19/FGF15 into the circulation, we pursued the potential of bile acids to improve glucose tolerance via a gut-brain axis involving FXR and FGF15/FGF19 within enterocytes and FGF receptors on hypothalamic AGRP/NPY neurons., Methods: A 5-day gavage of taurocholic acid, mirroring our previous protocol of a 5-day FGF19 treatment, was performed. Oral glucose tolerance tests in mice with genetic manipulations of FGF signaling and melanocortin signaling were used to define a gut-brain axis responsive to bile acids., Results: The taurocholic acid gavage led to increased serum concentrations of taurocholic acid as well as increases of FGF15 mRNA in the ileum and improved oral glucose tolerance in obese (ob/ob) mice. In contrast, lithocholic acid, an FXR antagonist but a potent agonist for GPBAR1, did not improve glucose tolerance. The positive response to taurocholic acid is dependent upon an intact melanocortinergic system as obese MC4R-null mice or ob/ob mice without AGRP did not show improvements in glucose tolerance after taurocholate gavage. We also tested the FGF receptor isoform necessary for the bile acid response, using AGRP:Fgfr1-/- and AGRP:Fgfr2-/- mice. While the absence of FGFR1 in AGRP/NPY neurons did not alter glucose tolerance after taurocholate gavage, manipulations of Fgfr2 caused bidirectional changes depending upon the experimental model. We hypothesized the existence of an endogenous hypothalamic FGF, most likely FGF17, that acted as a chronic activator of AGRP/NPY neurons. We developed two short peptides based on FGF8 and FGF17 that should antagonize FGF17 action. Both of these peptides improved glucose homeostasis after a 4-day course of central and peripheral injections. Significantly, daily average blood glucose from continuous glucose monitoring was reduced in all tested animals but glucose concentrations remained in the euglycemia range., Conclusions: We have defined a gut-brain axis that regulates glucose metabolism mediated by antagonistic fibroblast growth factors. From the intestine, bile acids stimulate FGF15 secretion, leading to activation of the FGF receptors in hypothalamic AGRP/NPY neurons. FGF receptor intracellular signaling subsequently silences AGRP/NPY neurons, leading to improvements of glucose tolerance that are likely mediated by the autonomic nervous system. Finally, short peptides that antagonize homodimeric FGF receptor signaling within the hypothalamus have beneficial effects on glucose homeostasis without inducing hypoglycemia. These peptides could provide a new mode of regulating glucose metabolism., (Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Obesity-induced white adipose tissue (WAT) fibrosis is believed to accelerate WAT dysfunction. However, the cellular origin of WAT fibrosis remains unclear. Here, we show that adipocyte platelet-derived growth factor receptor-α-positive (PDGFRα + ) progenitors adopt a fibrogenic phenotype in obese mice prone to visceral WAT fibrosis. More specifically, a subset of PDGFRα + cells with high CD9 expression (CD9 high ) originates pro-fibrotic cells whereas their CD9 low counterparts, committed to adipogenesis, are almost completely lost in the fibrotic WAT. PDGFRα pathway activation promotes a phenotypic shift toward PDGFRα + CD9 high fibrogenic cells, driving pathological remodeling and altering WAT function in obesity. These findings translated to human obesity as the frequency of CD9 high progenitors in omental WAT (oWAT) correlates with oWAT fibrosis level, insulin-resistance severity, and type 2 diabetes. Collectively, our data demonstrate that in addition to representing a WAT adipogenic niche, different PDGFRα + cell subsets modulate obesity-induced WAT fibrogenesis and are associated with loss of metabolic fitness., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Context: Extracellular matrix (ECM) in sc adipose tissue (scAT) undergoes pathological remodeling during obesity. However, its evolution during weight loss remains poorly explored., Objective: The objective of the investigation was to study the histological, transcriptomic, and physical characteristics of scAT ECM remodeling during the first year of bariatric surgery (BS)-induced weight loss and their relationships with metabolic and bioclinical improvements., Design, Setting, Patients, and Interventions: A total of 118 morbidly obese candidates for BS were recruited and followed up during 1 year after BS., Main Outcome Measures: scAT surgical biopsy and needle aspiration as well as scAT stiffness measurement were performed in three subgroups before and after BS. Fourteen nonobese, nondiabetic subjects served as controls., Results: Significantly increased picrosirius-red-stained collagen accumulation in scAT after BS was observed along with fat mass loss, despite metabolic and inflammatory improvements and undetectable changes of scAT stiffness. Collagen accumulation positively associated with M2-macrophages (CD163(+) cells) before BS but negatively afterward. Expression levels of genes encoding ECM components (eg, COL3A1, COL6A1, COL6A2, ELN), cross-linking enzymes (eg, lysyl oxidase [LOX], LOXL4, transglutaminase), metalloproteinases, and their inhibitors were modified 1 year after BS. LOX expression and protein were significantly decreased and associated with decreased fat mass as well as other cross-linking enzymes. Although total collagen I and VI staining decreased 1 year after BS, we found increased degraded collagen I and III in scAT, suggesting increased degradation., Conclusions: After BS-induced weight loss and related metabolic improvements, scAT displays major collagen remodeling with an increased picrosirius-red staining that relates to increased collagen degradation and importantly decreased cross-linking. These features are in agreement with adequate ECM adaptation during fat mass loss.

MAF1 is a global repressor of RNA polymerase III transcription that regulates the expression of highly abundant noncoding RNAs in response to nutrient availability and cellular stress. Thus, MAF1 function is thought to be important for metabolic economy. Here we show that a whole-body knockout of Maf1 in mice confers resistance to diet-induced obesity and nonalcoholic fatty liver disease by reducing food intake and increasing metabolic inefficiency. Energy expenditure in Maf1(-/-) mice is increased by several mechanisms. Precursor tRNA synthesis was increased in multiple tissues without significant effects on mature tRNA levels, implying increased turnover in a futile tRNA cycle. Elevated futile cycling of hepatic lipids was also observed. Metabolite profiling of the liver and skeletal muscle revealed elevated levels of many amino acids and spermidine, which links the induction of autophagy in Maf1(-/-) mice with their extended life span. The increase in spermidine was accompanied by reduced levels of nicotinamide N-methyltransferase, which promotes polyamine synthesis, enables nicotinamide salvage to regenerate NAD(+), and is associated with obesity resistance. Consistent with this, NAD(+) levels were increased in muscle. The importance of MAF1 for metabolic economy reveals the potential for MAF1 modulators to protect against obesity and its harmful consequences., (© 2015 Bonhoure et al.; Published by Cold Spring Harbor Laboratory Press.)

Consensus practices and regulatory guidance for liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) assays of small molecules are more aligned globally than for any of the other bioanalytical techniques addressed by the Global Bioanalysis Consortium. The three Global Bioanalysis Consortium Harmonization Teams provide recommendations and best practices for areas not yet addressed fully by guidances and consensus for small molecule bioanalysis. Recommendations from all three teams are combined in this report for chromatographic run quality, validation, and sample analysis run acceptance.

The transcription factor Gata6 regulates proliferation and differentiation of epithelial and endocrine cells and cancers. Among hematopoietic cells, Gata6 is expressed selectively in resident peritoneal macrophages. We thus examined whether the loss of Gata6 in the macrophage compartment affected peritoneal macrophages, using Lyz2-Cre x Gata6(flox/flox) mice to tackle this issue. In Lyz2-Cre x Gata6(flox/flox) mice, the resident peritoneal macrophage compartment, but not macrophages in other organs, was contracted, with only a third the normal number of macrophages remaining. Heightened rates of death explained the marked decrease in peritoneal macrophage observed. The metabolism of the remaining macrophages was skewed to favor oxidative phosphorylation and alternative activation markers were spontaneously and selectively induced in Gata6-deficient macrophages. Gene expression profiling revealed perturbed metabolic regulators, including aspartoacylase (Aspa), which facilitates generation of acetyl CoA. Mutant mice lacking functional Aspa phenocopied the higher propensity to death and led to a contraction of resident peritoneal macrophages. Thus, Gata6 regulates differentiation, metabolism, and survival of resident peritoneal macrophages., (© 2014 Gautier et al.)

Tight control of glucose excursions has been a long-standing goal of treatment for patients with type 2 diabetes mellitus in order to ameliorate the morbidity and mortality associated with hyperglycemia. Fibroblast growth factor (FGF) 19 is a hormone-like enterokine released postprandially that emerged as a potential therapeutic agent for metabolic disorders, including diabetes and obesity. Remarkably, FGF19 treatment has hypoglycemic actions that remain potent in models of genetic and acquired insulin resistance. Here, we provided evidence that the central nervous system responds to FGF19 administered in the periphery. Then, in two mouse models of insulin resistance, leptin-deficiency and high-fat diet feeding, third intra-cerebro-ventricular infusions of FGF19 improved glycemic status, reduced insulin resistance and potentiated insulin signaling in the periphery. In addition, our study highlights a new mechanism of central FGF19 action, involving the suppression of AGRP/NPY neuronal activity. Overall, our work unveils novel regulatory pathways induced by FGF19 that will be useful in the design of novel strategies to control diabetes in obesity.

We previously mapped a locus on BALB/c chromosome 2 associated with protection from leptin-deficiency-induced obesity. Here, we generated the corresponding congenic mouse strain by introgression of a segment of C57BL/6J chromosome 2 to the BALB/c background to confirm the genotype-phenotype associations. We found that the BALB/c alleles decreased fat mass expansion by limiting adipocyte hyperplasia and adipocyte hypertrophy. This was concomitant to an increase in adipocyte triglyceride lipase (ATGL)-mediated triglyceride breakdown and prolongation of ATGL half-life in adipose tissue. In addition, BALB/c alleles on chromosome 2 exerted a cell-autonomous role in restraining the adipogenic potential of preadipocytes. Within a 9.8-Mb critical interval, we identified a nonsynonymous coding single nucleotide polymorphism in the gene coding for the ubiquitin-conjugating enzyme E2L6 (Ube2l6, also known as Ubch8) and showed that the BALB/c allele of Ube2l6 is a hypomorph leading to the lack of UBE2L6 protein expression. Ube2l6 knockdown in 3T3-L1 adipocytes repressed adipogenesis. Thus, altered adipogenic potential caused by Ube2l6 knockdown is likely critically involved in BALB/c obesity resistance by inhibiting adipogenesis and reducing adipocyte numbers. Overall, we have identified a loss-of-function mutation in Ube2l6 that contributes to the chromosome 2 obesity quantitative trait locus.

pRb is frequently inactivated in tumours by mutations or phosphorylation. Here, we investigated whether pRb plays a role in obesity. The Arcuate nucleus (ARC) in hypothalamus contains antagonizing POMC and AGRP/NPY neurons for negative and positive energy balance, respectively. Various aspects of ARC neurons are affected in high-fat diet (HFD)-induced obesity mouse model. Using this model, we show that HFD, as well as pharmacological activation of AMPK, induces pRb phosphorylation and E2F target gene de-repression in ARC neurons. Some affected neurons express POMC; and deleting Rb1 in POMC neurons induces E2F target gene de-repression, cell-cycle re-entry, apoptosis, and a hyperphagia-obesity-diabetes syndrome. These defects can be corrected by combined deletion of E2f1. In contrast, deleting Rb1 in the antagonizing AGRP/NPY neurons shows no effects. Thus, pRb-E2F1 is an obesity suppression mechanism in ARC POMC neurons and HFD-AMPK inhibits this mechanism by phosphorylating pRb in this location.

A myriad of risk factors have been linked to an increase in the severity of the pandemic H1N1 2009 influenza A virus [A(H1N1)pdm09] including pregnancy and obesity where death rates can be elevated as compared to the general population. The goal of this review is to provide an overview of the influence of pregnancy and obesity on the reported cases of A(H1N1)pdm09 virus infection and of how the concurrent presence of these factors may have an exacerbating effect on infection outcome. Also, the hypothesized immunologic mechanisms that contribute to A(H1N1)pdm09 virus severity during pregnant or obese states are outlined. Identifying the mechanisms underlying the increased disease severity in these populations may result in improved therapeutic approaches and future pandemic preparedness., (© 2012 Blackwell Publishing Ltd.)

Although peroxisome proliferator-activated receptor γ (PPARγ) has anti-inflammatory actions in macrophages, which macrophage populations express PPARγ in vivo and how it regulates tissue homeostasis in the steady state and during inflammation remains unclear. We now show that lung and spleen macrophages selectively expressed PPARγ among resting tissue macrophages. In addition, Ly-6C(hi) monocytes recruited to an inflammatory site induced PPARγ as they differentiated to macrophages. When PPARγ was absent in Ly-6C(hi)-derived inflammatory macrophages, initiation of the inflammatory response was unaffected, but full resolution of inflammation failed, leading to chronic leukocyte recruitment. Conversely, PPARγ activation favored resolution of inflammation in a macrophage PPARγ-dependent manner. In the steady state, PPARγ deficiency in red pulp macrophages did not induce overt inflammation in the spleen. By contrast, PPARγ deletion in lung macrophages induced mild pulmonary inflammation at the steady state and surprisingly precipitated mortality upon infection with Streptococcus pneumoniae. This accelerated mortality was associated with impaired bacterial clearance and inability to sustain macrophages locally. Overall, we uncovered critical roles for macrophage PPARγ in promoting resolution of inflammation and maintaining functionality in lung macrophages where it plays a pivotal role in supporting pulmonary host defense. In addition, this work identifies specific macrophage populations as potential targets for the anti-inflammatory actions of PPARγ agonists.