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Classically, the regulation of energy balance has been based on central and peripheral mechanisms sensing energy, nutrients, metabolites, and hormonal cues. Several cellular mechanisms at central level, such as hypothalamic AMP-activated protein kinase (AMPK), integrate this information to elicit counterregulatory responses that control feeding, energy expenditure and glucose homeostasis, among other processes. Recent data have added more complexity to the homeostatic regulation of metabolism by introducing, for example, the key role of "traditional" senses and sensorial information in this complicated network. In this regard, current evidence is showing that olfaction plays a key and bidirectional role in energy homeostasis. While nutritional status dynamically and profoundly impacts olfactory sensitivity, the sense of smell is involved in food appreciation and selection, as well as in brown adipose tissue (BAT) thermogenesis and substrate utilization, with some newly described actors, such as olfactomedin 2 (OLFM2), likely playing a major role. Thus, olfactory inputs are contributing to the regulation of both sides of the energy balance equation, namely feeding and energy expenditure (EE), as well as whole-body metabolism. Here, we will review the current knowledge and advances about the role of olfaction in the regulation of energy homeostasis.

Context Sleep disruption is associated with worse glucose metabolic control and altered gut microbiota in animal models. Objective We aimed to evaluate the possible links among rapid eye movement (REM) sleep duration, continuous glucose levels, and gut microbiota composition. Methods This observational, prospective, real-life, cross-sectional case-control study included 118 (60 with obesity), middle-aged (39.1-54.8 years) healthy volunteers recruited at a tertiary hospital. Glucose variability and REM sleep duration were assessed by 10-day continuous glucose monitoring (CGM) (Dexcom G6) and wrist actigraphy (Fitbit Charge 3), respectively. The coefficient of variation (CV), interquartile range (IQR), and SD of glucose variability was assessed and the percentage of time in range (% TIR), at 126-139 mg/dL (TIR2), and 140-199 mg/dL (TIR3) were calculated. Shotgun metagenomics sequencing was applied to study gut microbiota taxonomy and functionality. Results Increased glycemic variability (SD, CV, and IQR) was observed among subjects with obesity in parallel to increased % TIR2 and % TIR3. REM sleep duration was independently associated with % TIR3 (β = −.339; P < .001) and glucose variability (SD, β = −.350; P < .001). Microbial taxa from the Christensenellaceae family (Firmicutes phylum) were positively associated with REM sleep and negatively with CGM levels, while bacteria from Enterobacteriacea family and bacterial functions involved in iron metabolism showed opposite associations. Conclusion Decreased REM sleep duration was independently associated with a worse glucose profile. The associations of species from Christensenellaceae and Enterobacteriaceae families with REM sleep duration and continuous glucose values suggest an integrated picture of metabolic health.

Dietary lipids can affect metabolic health through gut microbiota-mediated mechanisms, but the influence of lipid-microbiota interaction on liver steatosis is largely unknown. We investigated the impact of dietary lipids on human gut microbiota composition and the effects of microbiota-lipid interactions on steatosis in mice. In humans, low intake of saturated fatty acids (SFA) was associated with increased microbial diversity independent of fiber intake. In mice, poorly absorbed dietary long-chain SFA, particularly stearic acid, improved metabolism and steatosis. These benefits were dependent on the gut microbiota, as they were transmitted by microbial transfer. Diets enriched in polyunsaturated fatty acids were protective against steatosis but had minor influence on the microbiota. In summary, we find that diets enriched in poorly absorbed long-chain SFA modulate gut microbiota profiles independent of fiber intake, and this interaction is relevant to improve metabolism and decrease liver steatosis.

Lipopolysaccharide binding protein (Lbp) has been recently identified as a relevant component of innate immunity response associated to adiposity. Here, we aimed to investigate the impact of adipose tissue Lbp on weight gain and white adipose tissue (WAT) in male and female mice fed an obesogenic diet. Specific adipose tissue Lbp gene knockdown was achieved through lentiviral particles containing shRNA-Lbp injected through surgery intervention. In males, WAT Lbp mRNA levels increased in parallel to fat accretion, and specific WAT Lbp gene knockdown led to reduced body weight gain, decreased fat accretion-related gene and protein expression, and increased inguinal WAT basal lipase activity, in parallel to lowered plasma free fatty acids, leptin, triglycerides but higher glycerol levels, resulting in slightly improved insulin action in the insulin tolerance test. In both males and females, inguinal WAT Lbp gene knockdown resulted in increased Ucp1 and Ppargc1a mRNA and Ucp1 protein levels, confirming adipose Lbp as a WAT browning repressor. In perigonadal WAT, Lbp gene knockdown also resulted in increased Ucp1 mRNA levels, but only in female mice, in which it was 500-fold increased. These data suggest specific adipose tissue Lbp gene knockdown as a possible therapeutic approach in the prevention of obesity-associated fat accretion This work was partially supported by research grants PI16/02173, PI16/01173, PI18/01022, PI19/01712, PI20/00106, and PI21/01361 from the Instituto de Salud Carlos III from Spain, FEDER funds, and was also supported by Fundació Marató de TV3 (201612-30, 201612-31) and SGR 2017/00734. CIBEROBN Fisiopatología de la Obesidad y Nutrición is an initiative from the Instituto de Salud Carlos III from Spain

This work was supported by grants from the Ministerio de Ciencia, Innovación y Universidades (PID2019-104475GA-I00 to I.S, and PGC2018-097573-A-I00 to AC-R) and the European Foundation for the Study of Diabetes (EFSD) - EFSD/JDRF/Lilly Programme on Type 1 Diabetes Research to IS. FO (MS19/00109) is recipient of the Miguel Servet scheme, and AL (FI19/00045) was supported by the Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia, Innovación y Universidades, Gobierno de España (ES). HR-M (PRE2019-089350) is supported by predoctoral grant from the Ministerio de Ciencia, Innovación y Universidades, Gobierno de España (ES) IG-M, MS-C, JM-S and AO-G were supported by Predoctoral Fellowship Grants from the UPV/EHU (Universidad del Pais Vasco/ EuskalHerrikoUnibertsitatea) and the Basque Department of Education. MC is supported by the Fonds National de la RechercheScientifique (FNRS), the Francophone Foundation for Diabetes Research (sponsored by the French Diabetes Federation, Abbott, Eli Lilly, Merck Sharp & Dohme, and Novo Nordisk) and FF and MC by the EFSD/BoehringerIngelheim European Research Programme on Multi-System Challenges in Diabetes., González-Moro I., Rojas-Márquez H., Sebastian-delaCruz M., Mentxaka-Salgado J., Olazagoitia-Garmendia A., Mendoza L.M., Lluch A., Fantuzzi F., Lambert C., Ares Blanco J., Marselli L., Marchetti P., Cnop M., Delgado E., Fernández-Real J.M., Ortega F.J., Castellanos-Rubio A., Santin I.

Metabolic inflammation mediated obesity requires bacterial molecules to trigger immune and adipose cells leading to inflammation and adipose depot development. Beside the established gut microbiota dysbiosis we and others identified a leaky gut in obese patients and animal models as notably characterized by the existence of a tissue microbiota in the adipose fat pads. To identify its potential role, we here sequenced the bacterial 16S rRNA genes within the visceral adipose depot of obese patients. Immense surgical, biochemical and bioinformatic care were taken to avoid environmental contaminants. We performed different statistical discriminant analyses to identify specific signatures and constructed network of interactions between variables. The data show that a specific 16SrRNA gene signature was composed of numerous bacterial families discriminating lean versus obese and extremely obese patients. Burkholderiaceae, Yearsiniaceae, and Xanthomonadaceae were the main discriminant families, notably all gram negative. Interestingly, the Morganellaceae were totally absent from non-obese while preponderant in all obese patients. To generate hypotheses regarding their potential role we inferred metabolic pathways from the 16SrRNA gene signatures. We identified several pathways associated with adenosyl-cobalamine previously described to be linked with adipose tissue development. We further identified chorismate biosynthesis involved in aromatic amino-acid metabolism which could be important players. This innovative approach generates novel hypotheses regarding the gut to adipose tissue axis in obesity.

Aging biology entails a cell/tissue deregulated metabolism that affects all levels of biological organization. Therefore, the application of “omic” techniques that are closer to phenotype, such as metabolomics, to the study of the aging process should be a turning point in the definition of cellular processes involved. The main objective of the present study was to describe the changes in plasma metabolome associated with biological aging and the role of sex in the metabolic regulation during aging. A high-throughput untargeted metabolomic analysis was applied in plasma samples to detect hub metabolites and biomarkers of aging incorporating a sex/gender perspective. A cohort of 1030 healthy human adults (45.9% females, and 54.1% males) from 50 to 98 years of age was used. Results were validated using two independent cohorts (1: n = 146, 53% females, 30–100 years old; 2: n = 68, 70% females, 19–107 years old). Metabolites related to lipid and aromatic amino acid (AAA) metabolisms arose as the main metabolic pathways affected by age, with a high influence of sex. Globally, we describe changes in bioenergetic pathways that point to a decrease in mitochondrial β-oxidation and an accumulation of unsaturated fatty acids and acylcarnitines that could be responsible for the increment of oxidative damage and inflammation characteristic of this physiological process. Furthermore, we describe for the first time the importance of gut-derived AAA catabolites in the aging process describing novel biomarkers that could contribute to better understand this physiological process but also age-related diseases. This research was funded by the Spanish Ministry of Science,Innovation, and Universities (grant RTI2018-099200-B- I00, and PID2022-143140OB-I00, co-funded by the European Regional Development Fund. “A way to build Europe”), and the Generalitat of Catalonia (Agency for Management of University and Research Grants [2021SGR00990] and Department of Health [SLT002/16/00250])to R.P. The work is also supported by “la Caixa” Foundation (Grant Agreement LCF/PR/HR21/52410002) to M.J. IRBLleida is a CERCAProgramme/Generalitat of Catalonia. This work was also partiallysupported by Instituto de Salud Carlos III (Madrid, Spain) through the research grants PI15/01934, PI18/01022, PI20/01090, and PI21/01361 (co-funded by the European Regional Development Fund. “A way to make Europe”), and the Catalan Government (AGAUR,#SGR2017-0734, ICREA Academia Award 2021) to J.M.F-R.

Understanding the brain changes occurring during aging can provide new insights for developing treatments that alleviate or reverse cognitive decline. Neurostimulation techniques have emerged as potential treatments for brain disorders and to improve cognitive functions. Nevertheless, given the ethical restrictions of neurostimulation approaches, in silico perturbation protocols based on causal whole-brain models are fundamental to gaining a mechanistic understanding of brain dynamics. Furthermore, this strategy could serve to identify neurophysiological biomarkers differentiating between age groups through an exhaustive exploration of the global effect of all possible local perturbations. Here, we used a resting-state fMRI dataset divided into middle-aged (N =310

Lipopolysaccharide binding protein (LBP) knockout mice models are protected against the deleterious effects of major acute inflammation but its possible physiological role has been less well studied. We aimed to evaluate the impact of liver LBP downregulation (using nanoparticles containing siRNA- Lbp) on liver steatosis, inflammation and fibrosis during a standard chow diet (STD), and in pathological non-obesogenic conditions, under a methionine and choline deficient diet (MCD, 5 weeks). Under STD, liver Lbp gene knockdown led to a significant increase in gene expression markers of liver inflammation (Itgax, Tlr4, Ccr2, Ccl2 and Tnf), liver injury (Krt18 and Crp), fibrosis (Col4a1, Col1a2 and Tgfb1), endoplasmic reticulum (ER) stress (Atf6, Hspa5 and Eif2ak3) and protein carbonyl levels. As expected, the MCD increased hepatocyte vacuolation, liver inflammation and fibrosis markers, also increasing liver Lbp mRNA. In this model, liver Lbp gene knockdown resulted in a pronounced worsening of the markers of liver inflammation (also including CD68 and MPO activity), fibrosis, ER stress and protein carbonyl levels, all indicative of non-alcoholic steatohepatitis (NASH) progression. At cellular level, Lbp gene knockdown also increased expression of the proinflammatory mediators (Il6, Ccl2), and markers of fibrosis (Col1a1, Tgfb1) and protein carbonyl levels. In agreement with these findings, liver LBP mRNA in humans positively correlated with markers of liver damage (circulating hsCRP, ALT activity, liver CRP and KRT18 gene expression), and with a network of genes involved in liver inflammation, innate and adaptive immune system, endoplasmic reticulum stress and neutrophil degranulation (all with q-value0.05). In conclusion, current findings suggest that a significant downregulation in liver LBP levels promotes liver oxidative stress and inflammation, aggravating NASH progression, in physiological and pathological non-obesogenic conditions.

Objective: To investigate the potential role of EGFR, ErbBs receptors and neuregulins in human adipose tissue physiology in obesity. Methods: Gene expression analysis in human subcutaneous (SAT) and visceral (VAT) adipose tissue in three independent cohorts [two cross-sectional (N = 150, N = 87) and one longitudinal (n = 25)], and in vitro gene knockdown and overexpression experiments were performed. Results: While both SAT and VAT ERBB2 and ERBB4 mRNA increased in obesity, SAT EGFR mRNA was negatively correlated with insulin resistance, but did not change in obesity. Of note, both SAT and VAT EGFR mRNA were significantly associated with adipogenesis and increased during human adipocyte differentiation. In vitro experiments revealed that EGFR, but not ERBB2 and ERBB4, gene knockdown in preadipocytes and in fully differentiated human adipocytes resulted in decreased expression of adipogenic-related genes. ERBB2 gene knockdown also reduced gene expression of fatty acid synthase in fully differentiated adipocytes. In addition, neuregulin 2 (NRG2) mRNA was associated with expression of adipogenic genes in human adipose tissue and adipocytes, and its overexpression increased expression of EGFR and relevant adipogenic genes. Conclusions: This study demonstrates the association between adipose tissue ERBB2 and obesity, confirms the relevance of EGFR on human adipogenesis, and suggests a possible adipogenic role of NRG2.

Dipeptidyl peptidase 9 (DPP9) is a member of the dipeptidyl peptidase IV family. Inhibition of DPP9 has recently been shown to activate the nucleotide-binding domain leucine-rich repeat 1 (NLRP1) inflammasome. NLRP1 is known to bind nucleic acids with high affinity and directly interact with double stranded RNA, which plays a key role in viral replication. DPP9 has also recently emerged as a key gene related to lung-inflammation in critical SARS-CoV-2 infection. Importantly, DPP9 activity is strongly dependent on the oxidative status. Here, we explored the potential role of DPP9 in the gastrointestinal tract. We performed transcriptomics analyses of colon (microarray, n = 37) and jejunal (RNA sequencing, n = 31) biopsies from two independent cohorts as well as plasma metabolomics analyses in two independent cohorts (n = 37 and n = 795). The expression of DPP9 in the jejunum, colon, and blood was significantly associated with circulating biomarkers of oxidative stress (uric acid, bilirubin). It was also associated positively with the expression of transcription factors (NRF-2) and genes (SOD, CAT, GPX) encoding for antioxidant enzymes, but negatively with that of genes (XDH, NOX) and transcription factors (NF-KB) involved in ROS-generating enzymes. Gene co-expression patterns associated with DPP9 identified several genes participating in antiviral pathways in both tissues. Notably, DPP9 expression in the colon and plasma was strongly positively associated with several circulating nucleotide catabolites (hypoxanthine, uric acid, 3-ureidopropionic acid) with important roles in the generation of ROS and viral infection, as well as other metabolites related to oxidative stress (Resolvin D1, glutamate-containing dipeptides). Gene-drug enrichment analyses identified artenimol, puromycin, anisomycin, 3-phenyllactic acid, and linezolid as the most promising drugs targeting these DPP9-associated genes. We have identified a novel potential pathogenic mechanism of viral infection in the digestive tract and promising existing drugs that can be repositioned against viral infection This work was partially supported by Fundació Marató de TV3 research grant number 201612-31 and by Instituto de Salud Carlos III (ISCIII, Madrid, Spain) through the project PI20/01090 (co-funded by the European Union under the European Regional Development Fund (FEDER). “A way to make Europe”) to J.M.-P. Á.d.C.-I. is funded by Girona Biomedical Research Institute (Girona, Spain) through the Horizon 2020 Framework Programme of the European Union under the Marie Skłodowska-Curie Innovative Training Network grant agreement No 859890. M.A.-R. is funded by Instituto de Salud Carlos III (Madrid, Spain) through a predoctoral Río Hortega contract CM19/00190 (co-funded by European Regional Development Fund “Investing in your future”). J.M.-P. is funded by Instituto de Salud Carlos III (Madrid, Spain) through the Miguel Servet Program CP18/00009 (co-funded by European Regional Development Fund “Investing in your future”)

ObjectiveThe metalloprotease ADAM17 (also called TACE) plays fundamental roles in homeostasis by shedding key signaling molecules from the cell surface. Although its importance for the immune system and epithelial tissues is well-documented, little is known about the role of ADAM17 in metabolic homeostasis. The purpose of this study was to determine the impact of ADAM17 expression, specifically in adipose tissues, on metabolic homeostasis.MethodsWe used histopathology, molecular, proteomic, transcriptomic, in vivo integrative physiological and ex vivo biochemical approaches to determine the impact of adipose tissue-specific deletion of ADAM17 upon adipocyte and whole organism metabolic physiology.ResultsADAM17adipoq-creΔ/Δ mice exhibited a hypermetabolic phenotype characterized by elevated energy consumption and increased levels of adipocyte thermogenic gene expression. On a high fat diet, these mice were more thermogenic, while exhibiting elevated expression levels of genes associated with lipid oxidation and lipolysis. This hypermetabolic phenotype protected mutant mice from obesogenic challenge, limiting weight gain, hepatosteatosis and insulin resistance. Activation of beta-adrenoceptors by the neurotransmitter norepinephrine, a key regulator of adipocyte physiology, triggered the shedding of ADAM17 substrates, and regulated ADAM17 expression at the mRNA and protein levels, hence identifying a functional connection between thermogenic licensing and the regulation of ADAM17. Proteomic studies identified Semaphorin 4B (SEMA4B), as a novel ADAM17-shed adipokine, whose expression is regulated by physiological thermogenic cues, that acts to inhibit adipocyte differentiation and dampen thermogenic responses in adipocytes. Transcriptomic data showed that cleaved SEMA4B acts in an autocrine manner in brown adipocytes to repress the expression of genes involved in adipogenesis, thermogenesis, and lipid uptake, storage and catabolism.ConclusionsOur findings identify a novel ADAM17-dependent axis, regulated by beta-adrenoceptors and mediated by the ADAM17-cleaved form of SEMA4B, that modulates energy balance in adipocytes by inhibiting adipocyte differentiation, thermogenesis and lipid catabolism.

Background Succinate is produced by both human cells and by gut bacteria and couples metabolism to inflammation as an extracellular signaling transducer. Circulating succinate is elevated in patients with obesity and type 2 diabetes and is linked to numerous complications, yet no studies have specifically addressed the contribution of gut microbiota to systemic succinate or explored the consequences of reducing intestinal succinate levels in this setting. Results Using germ-free and microbiota-depleted mouse models, we show that the gut microbiota is a significant source of circulating succinate, which is elevated in obesity. We also show in vivo that therapeutic treatments with selected bacteria diminish the levels of circulating succinate in obese mice. Specifically, we demonstrate that Odoribacter laneus is a promising probiotic based on its ability to deplete succinate and improve glucose tolerance and the inflammatory profile in two independent models of obesity (db/db mice and diet-induced obese mice). Mechanistically, this is partly mediated by the succinate receptor 1. Supporting these preclinical findings, we demonstrate an inverse correlation between plasma and fecal levels of succinate in a cohort of patients with severe obesity. We also show that plasma succinate, which is associated with several components of metabolic syndrome including waist circumference, triglycerides, and uric acid, among others, is a primary determinant of insulin sensitivity evaluated by the euglycemic-hyperinsulinemic clamp. Conclusions Overall, our work uncovers O. laneus as a promising next-generation probiotic to deplete succinate and improve glucose tolerance and obesity-related inflammation.

Circulating lipopolysaccharide-binding protein (LBP) is increased in individuals with liver steatosis. We aimed to evaluate the possible impact of liver LBP downregulation using lipid nanoparticle-containing chemically modified LBP small interfering RNA (siRNA) (LNP-Lbp UNA-siRNA) on the development of fatty liver. Weekly LNP-Lbp UNA-siRNA was administered to mice fed a standard chow diet, a high-fat and high-sucrose diet, and a methionine- and choline-deficient diet (MCD). In mice fed a high-fat and high-sucrose diet, which displayed induced liver lipogenesis, LBP downregulation led to reduced liver lipid accumulation, lipogenesis (mainly stearoyl-coenzyme A desaturase 1 [Scd1]) and lipid peroxidation-associated oxidative stress markers. LNP-Lbp UNA-siRNA also resulted in significantly decreased blood glucose levels during an insulin tolerance test. In mice fed a standard chow diet or an MCD, in which liver lipogenesis was not induced or was inhibited (especially Scd1 mRNA), liver LBP downregulation did not impact on liver steatosis. The link between hepatocyte LBP and lipogenesis was further confirmed in palmitate-treated Hepa1-6 cells, in primary human hepatocytes, and in subjects with morbid obesity. Altogether, these data indicate that siRNA against liver Lbp mRNA constitutes a potential target therapy for obesity-associated fatty liver through the modulation of hepatic Scd1.

Adipose tissue is a source of multiple factors that modulate systemic insulin sensitivity and cardiovascular risk. Taurine is obtained from the diet but it is less known that it is endogenously synthesized by cysteine dioxygenase type 1 (CDO1). CDO1 exerts a role in adipose tissue from rodent models, but the potential translational value in humans is not available in the literature.CDO1 gene expression was analysed in visceral and subcutaneous adipose tissue samples in association with metabolic traits in participants with different degrees of obesity in four independent cohorts. CDO1 was also evaluated in isolated human adipocytes in vitro. Mechanistically, CDO1gene knockdown (KD) of human preadipocytes and adipose-derived mesenchymal stem cells (ASC52telo) (using lentiviral particles) was also evaluated. Mitochondrial respiratory function of adipocytes was evaluated using Seahorse.Both visceral (VAT) and subcutaneous adipose tissue (SAT) CDO1 mRNA was associated with gene expression markers of adipose tissue function in the four cohorts. Higher CDO1 expression was linked to decreased fasting triglycerides and blood HbA1c even after adjusting by age, BMI and sex. In addition, CDO1 mRNA positively correlated with the expression of genes involved in adipogenesis and negatively with different inflammatory markers. Both VAT and SAT CDO1 mRNA was mainly expressed in adipocytes and significantly increased during adipocyte differentiation, but attenuated under inflammatory conditions. Mechanistically, CDO1 gene KD reduced taurine biosynthesis, evidencing lower CDO1 activity. In both human preadipocytes and ASC52telo cells, CDO1 gene KD resulted in decreased gene expression markers of adipogenesis (ADIPOQ, FABP4, FASN, SLC2A4, CEBPA) and increased inflammatory genes (TNF and IL6) during adipocyte differentiation. Of note, CDO1 gene KD led to decreased mitochondrial respiratory function in parallel to decreased expression of mitochondrial function-, but not biogenesis-related genes.Current findings show the relevance of CDO1 in adipose tissue physiology, suggesting its contribution to an improved systemic metabolic profile.This work was partially supported by research grants PI16/01173, PI19/01712, PI20/01090 and PI21/01361 from the Instituto de Salud Carlos III from Spain, Fondo Europeo de Desarrollo Regional (FEDER) funds, and VII Spanish Diabetes Association grants to Basic Diabetes Research Projects led by young researchers.

Substantial levels of lysozyme in adipose tissue in association to obesity have been recently demonstrated in mice and humans. In addition, experiments in mice suggest that lysozyme might impact on adipose tissue adipogenesis. To further investigate the relationship between lysozyme and adipogenesis, in the present study, we aimed to study lysozyme (Lyz2) during 3T3-L1 adipocyte differentiation and its possible role in adipogenesis. Time course experiment during 3T3-L1 adipocyte differentiation indicated that Lyz2 gene expression decreased at day 4, which was caused by isobutylmethylxanthine administration, and recovered at the end of the process (day 8). Importantly, the impact of isobutylmethylxanthine-induced downregulation of Lyz2 gene expression on adipogenesis was not comparable to that observed in the full cocktail, questioning whether the reduction in lysozyme at early stage of adipocyte differentiation is relevant to this process. In fact, the depletion in Lyz2 expression had a negative impact on adipogenesis, and rosiglitazone administration failed to compensate for the anti-adipogenic effect observed in Lyz2 gene knockdown cells. Otherwise, when Lyz2 gene knockdown cells were co-cultured with control cells, these cells had higher expression of adipogenic genes than those co-cultured with themselves at the end of adipocyte differentiation. In conclusion, this study suggests that lysozyme expression in 3T3-L1 cells sustains expression of adipogenic genes and adipocyte differentiation.

Excess iron is known to trigger adipose tissue dysfunction and insulin resistance. Circulating markers of iron status have been associated with obesity and adipose tissue in cross-sectional studies. We aimed to evaluate whether iron status is linked to changes in abdominal adipose tissue longitudinally. Subcutaneous abdominal tissue (SAT) and visceral adipose tissue (VAT) and its quotient (pSAT) were assessed using magnetic resonance imaging (MRI), at baseline and after one year of follow-up, in 131 (79 in follow-up) apparently healthy subjects, with and without obesity. Insulin sensitivity (euglycemic– hyperinsulinemic clamp) and markers of iron status were also evaluated. Baseline serum hepcidin (p = 0.005 and p = 0.002) and ferritin (p = 0.02 and p = 0.01)) were associated with an increase in VAT and SAT over one year in all subjects, while serum transferrin (p = 0.01 and p = 0.03) and total iron-binding capacity (p = 0.02 and p = 0.04) were negatively associated. These associations were mainly observed in women and in subjects without obesity, and were independent of insulin sensitivity. After controlling for age and sex, serum hepcidin was significantly associated with changes in subcutaneous abdominal tissue index (iSAT) (β = 0.406, p = 0.007) and visceral adipose tissue index (iVAT) (β = 0.306, p = 0.04), while changes in insulin sensitivity (β = 0.287, p = 0.03) and fasting triglycerides (β = −0.285, p = 0.03) were associated with changes in pSAT. These data indicated that serum hepcidin are associated with longitudinal changes in SAT and VAT, independently of insulin sensitivity. This would be the first prospective study evaluating the redistribution of fat according to iron status and chronic inflammation.

Recent studies in mice and humans demonstrated the relevance of H

Colorectal cancer is the second-leading oncological cause of death worldwide1. Despite advances in treatment, there is still a risk of local and distant recurrence, which impacts on long-term outcomes This study was awarded a grant by the ‘Asociación Española de Coloproctolgía’ and ‘Col·legi Oficial de Metges de Girona—Joan Bruguera Grant’ in 2021.

BACKGROUND AND OBJECTIVES The importance of hydrogen sulfide is increasingly recognized in the pathophysiology of obesity and type 2 diabetes in animal models. Very few studies have evaluated circulating sulfides in humans, with discrepant results. Here, we aimed to investigate serum sulfide levels according to obesity. SUBJECTS AND METHODS Serum sulfide levels were analyzed, using a selective fluorescent probe, in two independent cohorts [cross-sectionally in discovery (n = 139) and validation (n = 71) cohorts, and longitudinally in 82 participants from discovery cohort]. In the validation cohort, blood gene expression of enzymes contributing to H2S generation and consumption were also measured. RESULTS In the discovery cohort, serum sulfide concentration was significantly increased in subjects with morbid obesity at baseline and follow-up, and positively correlated with BMI and fat mass, but negatively with total cholesterol, haemoglobin, serum ferritin, iron and bilirubin after adjusting by age, gender and fat mass. Fat mass (β = 0.51, t = 3.67, p

Summary Background & aims Insulin resistance (IR) is one of the main risk factor for type 2 diabetes mellitus (T2DM). Nevertheless, its underlying pathophysiology is not completely established because IR is triggered by a complex interconnection of numerous factors impairing metabolism, promoting metabolome changes. Methods We used a metabolomics approach to identify plasma and faecal metabolites related to IR and obesity. We explored a cohort of 44 subjects at baseline, with 30 of them followed two years thereafter in a longitudinal study after an hypocaloric diet in the obese subjects. Results In all individuals as a whole, 11 plasma metabolites positively associated with BMI (acetoacetate, creatinine, glycerol, glycerol of lipids, VLDL, fatty esters, myo-inositol, phenylalanine, threonine, tyrosine and valine) and one negatively (phosphocholine), with similar associations at baseline and follow-up. Four of these metabolites (myo-inositol, valine, acetoacetate and phosphocholine) remained significant within obese and non-obese groups. Thirteen faecal metabolites positively associated with BMI at baseline and one negatively (glutamine). However, these correlations did not remain significant at follow-up. The correlations were not always consistent at baseline and at follow-up and the metabolites that showed significant correlations were different for the obese group compared with the control group. The percent change in plasma Δethanolamine, Δglucose, Δuracil and Δhypoxanthine were positively associated with ΔBMI. The percent change in plasma Δphosphocholine and of faecal Δhydroxyphenylacetate, and Δ2-hydroxyphenylacetate were associated with ΔHOMA-IR in those patients that lost weight. Faecal branched chain amino acids (BCAAs) in faeces were associated with IR, following a similar pattern to that described for plasma BCAAs. Choline derivates had an opposite behaviour. Conclusions The integration of plasma and faecal metabolites represents a valuable fingerprint that could help in the identification of patients at risk for IR and in the design of novel therapeutic strategies to prevent IR and the development of overt T2DM in the context of obesity. The results are coherent with diet having a much greater impact on faecal metabolomic profile than on plasma metabolome.

BACKGROUND/OBJECTIVES: Survivin is an oncogene associated with a decrease in apoptosis, an increase in tumor growth, and poor clinical outcome of diverse malignancies. A correlation between obesity, cancer, and survivin is reported in the literature. To date, the impact of weight loss on change in survivin levels is understudied. This study was aimed at: (1) comparing survivin levels in adipose tissue (AT) from lean and obese animal models and evaluating changes after weight loss induced by energy restriction and/or exercise; (2) comparing survivin levels in normal weighted and obese humans and evaluating changes in survivin levels after weight loss induced by a very-low-calorie ketogenic diet (VLCKD) or bariatric surgery in AT and/or blood leukocytes (PBL/PBMCs). SUBJECTS/METHODS: Survivin expression was evaluated in subcutaneous (SAT) and visceral (VAT) AT derived from animal models of monogenic (Zucker rats) and diet-induced obesity (Sprague Dawley rats and C57BL/6J mice) and after a 4-week weight-loss protocol of energy restriction and/or exercise. Plasma was used to measure the inflammatory status. Survivin expression was also evaluated in PBMCs from patients with obesity and compared with normal weight, in PBLs after VLCKD, and in SAT and/or PBLs after bariatric surgery. RESULTS: Survivin expression was specifically higher in VAT from obese that lean animals, without differences in SAT. It decreased after weight loss induced by energy restriction and correlated with adiposity and inflammatory markers. In humans, the correlation between being obese and higher levels of survivin was confirmed. In obese subjects, survivin levels were reduced following weight loss after either VLCKD or bariatric surgery. Particularly, a decrease in PBMCs expression (not in SAT one) was found after surgery. CONCLUSIONS: Weight loss is effective in decreasing survivin levels. Also, PBL/PBMC should be regarded as appropriate mirror of survivin levels in VAT for the identification of an obesity-related protumoral microenvironment.

Objective Obesity is the result of positive energy balance. It can be caused by excessive energy consumption but also by decreased energy dissipation, which occurs under several conditions including when the development or activation of brown adipose tissue (BAT) is impaired. Here we evaluated whether iRhom2, the essential cofactor for the Tumour Necrosis Factor (TNF) sheddase ADAM17/TACE, plays a role in the pathophysiology of metabolic syndrome. Methods We challenged WT versus iRhom2 KO mice to positive energy balance by chronic exposure to a high fat diet and then compared their metabolic phenotypes. We also carried out ex vivo assays with primary and immortalized mouse brown adipocytes to establish the autonomy of the effect of loss of iRhom2 on thermogenesis and respiration. Results Deletion of iRhom2 protected mice from weight gain, dyslipidemia, adipose tissue inflammation, and hepatic steatosis and improved insulin sensitivity when challenged by a high fat diet. Crucially, the loss of iRhom2 promotes thermogenesis via BAT activation and beige adipocyte recruitment, enabling iRhom2 KO mice to dissipate excess energy more efficiently than WT animals. This effect on enhanced thermogenesis is cell-autonomous in brown adipocytes as iRhom2 KOs exhibit elevated UCP1 levels and increased mitochondrial proton leak. Conclusion Our data suggest that iRhom2 is a negative regulator of thermogenesis and plays a role in the control of adipose tissue homeostasis during metabolic disease., Highlights • Deletion of iRhom2 protects mice from metabolic syndrome. • In obesity, iRhom2 deletion increases energy expenditure, thermogenesis and white adipose tissue beiging. • iRhom2 deletion enhances thermogenesis in naïve brown adipocytes.

Background: Obstructive sleep apnea (OSA) is a common disease caused by repeated episodes of collapse of the upper airway during sleep and is associated with the development of cardiovascular disease (CVD). However, there is high heterogeneity in the impact of OSA on patients. Until now, the profile of OSA patients at risk of developing CVD has not been defined, including the measurable variables that could be used to predict the CVD risk of a patient with OSA. Objective: The aim of this study was to identify the microRNA (mi­RNA) profile associated with CVD in patients with OSA. Method: This is an observational, cross-sectional study that included 132 male patients. Three groups were defined as OSA patients, OSA patients with hypertension, and OSA patients who developed a major cardiovascular event. Polysomnography and ambulatory blood pressure measurements were performed. The expression profiling of 188 miRNAs in plasma was performed in 21 subjects (matched by BMI and age) by the TaqMan low density array (TLDA). miRNAs differentially expressed in the different subgroups of patients and miRNAs that correlated with the cardiovascular risk SCORE were selected for validation by RT-qPCR in the 111 remaining patients. Results: From the TLDA analysis, 7 miRNAs were selected for validation. Differential expression was not confirmed in any of the miRNAs. miR-143 was associated with nocturnal systolic blood pressure. miR-107 correlated with 24-h blood pressure parameters and with nocturnal hypertension. miR-486 was associated with the cardiovascular risk SCORE. Conclusions: The circulating profile of miRNAs does not seem to be different in any of the subgroups of patients with OSA and different cardiovascular risk factors. Nevertheless, miR-107 and miR-143 are associated with specific blood pressure parameters in patients with OSA and miR-486 is associated with the cardiovascular risk SCORE.

Growing evidence implicates the gut microbiome in cognition. Viruses, the most abundant life entities on the planet, are a commonly overlooked component of the gut virome, dominated by the Caudovirales and Microviridae bacteriophages. Here, we show in a discovery (n = 114) and a validation cohort (n = 942) that subjects with increased Caudovirales and Siphoviridae levels in the gut microbiome had better performance in executive processes and verbal memory. Conversely, increased Microviridae levels were linked to a greater impairment in executive abilities. Microbiota transplantation from human donors with increased specific Caudovirales (>90% from the Siphoviridae family) levels led to increased scores in the novel object recognition test in mice and up-regulated memory-promoting immediate early genes in the prefrontal cortex. Supplementation of the Drosophila diet with the 936 group of lactococcal Siphoviridae bacteriophages resulted in increased memory scores and upregulation of memory-involved brain genes. Thus, bacteriophages warrant consideration as novel actors in the microbiome-brain axis., This work was partially funded by the Instituto de Salud Carlos III (Madrid, Spain) through the project PI15/01934, PI18/01022, PI21/01361) to J.M.F.-R. and the project PI20/01090 (co-funded by the European Regional Development Fund. “A way to make Europe”) to J.M.-P., the grants SAF2015-65878-R from the Ministry of Economy and Competitiveness, Prometeo/2018/A/133 from Generalitat Valenciana, Spain and also by the Fondo Europeo de Desarrollo Regional (FEDER) funds, European Commission (FP7, NeuroPain #2013-602891), the Catalan Government (AGAUR, #SGR2017-669, #2017 SGR- 734, ICREA Academia Award 2015 to R.M. and ICREA Academia Award 2022 to J.M.F.R.), the Spanish Instituto de Salud Carlos III (RTA, #RD16/0017/0020), the European Regional Development Fund (project No. 01.2.2-LMT-K-718-02-0014) under grant agreement with the Research Council of Lithuania (LMTLT), and the Project ThinkGut (EFA345/19) 65% co-financed by the European Regional Development Fund (ERDF) through the Interreg V-A Spain-France-Andorra programme (POCTEFA 2014-2020). CIBERobn is also co-funded by the European Regional Development Fund. We also acknowledge the funding from the Spanish Ministry of Science, Innovation and Universities (RTI2018-099200-B-I00), and the Generalitat of Catalonia (Agency for Management of University and Research grants (2017SGR696) and Department of Health (SLT002/16/00250)) to R.M M.A.-R. is funded by the Instituto de Salud Carlos III, Río Hortega (CM19/00190). J.M.-P. is funded by the Miguel Servet Program from the Instituto de Salud Carlos III (ISCIII CP18/00009), co-funded by the European Social Fund “Investing in your future.” A.C.-N. is funded by the Instituto de Salud Carlos III, Sara Borrell. MMG was funded by the Spanish Ministry of Science, Innovation and Universities RTI2018-094248-B-I00.

The microbiota-gut-brain axis has emerged as a novel target in depression, a disorder with low treatment efficacy. However, the field is dominated by underpowered studies focusing on major depression not addressing microbiome functionality, compositional nature, or confounding factors. We applied a multi-omics approach combining pre-clinical models with three human cohorts including patients with mild depression. Microbial functions and metabolites converging onto glutamate/GABA metabolism, particularly proline, were linked to depression. High proline consumption was the dietary factor with the strongest impact on depression. Whole-brain dynamics revealed rich club network disruptions associated with depression and circulating proline. Proline supplementation in mice exacerbated depression along with microbial translocation. Human microbiota transplantation induced an emotionally impaired phenotype in mice and alterations in GABA-, proline-, and extracellular matrix-related prefrontal cortex genes. RNAi-mediated knockdown of proline and GABA transporters in Drosophila and mono-association with L. plantarum, a high GABA producer, conferred protection against depression-like states. Targeting the microbiome and dietary proline may open new windows for efficient depression treatment., This work was partially supported by Instituto de Salud Carlos III (Madrid, Spain) through the research grants PI15/01934, PI18/01022, and PI21/01361 to J.M.F.-R. and PI20/01090 (co-funded by the European Regional Development Fund. “A way to make Europe”) to J.M.-P.; the Catalan Government (AGAUR, #SGR2017-0734, ICREA Academia Award 2021) to J.M.F.-R.; the Spanish Ministry of Science, Innovation and Universities (PID2019-105969GB-I00); Generalitat Valenciana (Prometeo/2018/133), Spain; and Fondo Europeo de Desarrollo Regional (FEDER) funds to A.M. This work was also supported by the European Commission (FP7, NeuroPain #2013-602891); the Catalan Government (AGAUR, #SGR2017-669, ICREA Academia Award 2020) to R.M.; the Spanish Instituto de Salud Carlos III (RTA, #RD16/0017/0020) to R.M.; Ministry of Science and Innovation and State Research Agency (#PID2020- 120029GB-I00/MICIN/AEI/10.13039/501100011033) to R.M.; the European Regional Development Fund (project no. 01.2.2-LMT-K-718-02-0014) under grant agreement with the Research Council of Lithuania (LMTLT); and the Project ThinkGut (EFA345/19), 65% co-financed by the European Regional Development Fund (ERDF) through the Interreg V-A Spain-France-Andorra program (POCTEFA, 2014–2020). We also acknowledge funding from the Spanish Ministry of Science, Innovation and Universities (RTI2018-099200-B-I00) and the Generalitat of Catalonia (Agency for Management of University and Research Grants [2017SGR696] and Department of Health [SLT002/16/00250]) to R.P. M.A.-R. is funded by Instituto de Salud Carlos III, Río Hortega (CM19/00190). J.M.-P. is funded by a Miguel Servet contract (CP18/00009) from the Instituto de Salud Carlos III. J.S. is funded by a predoctoral PERIS contract (SLT002/16/00250) from the Catalan Government. M.J. is a professor under “Serra Hunter” program (Generalitat de Catalunya).

Body iron excess appears to be related to insulin resistance and cardiometabolic risk and increased oxidative stress might be involved in this relationship. Very few studies have described the association between soluble transferrin receptor (sTfR) levels and cardiometabolic risk in the general population or antioxidant status. There were 239 subjects (20–65 years old) included in this cross-sectional study. Linear regressions adjusting for BMI, menopausal status, insulin resistance (HOMA-IR), physical inactivity, alcohol intake and subclinical/chronic inflammation were used to describe the association between sTfR, total antioxidant capacity (TAC), and measures of cardio-metabolic risk. sTfR levels were positively associated with TAC in men (βeta [95% confidence interval ]: 0.31 [0.14 to 0.48]) and women (βeta = 0.24 [0.07 to 0.40]) in non-adjusted and adjusted models (p < 0.05). In men, sTfR levels were inversely associated with waist circumference (βeta [95% confidence interval]: −1.12 [−2.30 to −0.22]) and fasting glucose (−2.7 (−4.82 to −0.57), and positively with LDL cholesterol (12.41 (6.08 to 18.57) before and after adjustments for confounding variables. LDL cholesterol had a significant and positive association with TAC in non-adjusted and adjusted models in men (p < 0.05). sTfR levels are significantly associated with antioxidant status and a few specific cardio-metabolic risk variables, independently of covariates that included serum ferritin and hepcidin. This might imply that iron biomarkers in regard to cardiometabolic risk reflect physiological contexts other than iron metabolism.

The adipokine Neuregulin 4 (Nrg4) protects against obesity-induced insulin resistance. Here, we analyze how the downregulation of Nrg4 influences insulin action and the underlying mechanisms in adipocytes. Validated shRNA lentiviral vectors were used to generate scramble (Scr) and Nrg4 knockdown (KD) 3T3-L1 adipocytes. Adipogenesis was unaffected in Nrg4 KD adipocytes, but there was a complete impairment of the insulin-induced 2-deoxyglucose uptake, which was likely the result of reduced insulin receptor and Glut4 protein. Downregulation of Nrg4 enhanced the expression of proinflammatory cytokines. Anti-inflammatory agents recovered the insulin receptor, but not Glut4, content. Proteins enriched in Glut4 storage vesicles such as the insulin-responsive aminopeptidase (IRAP) and Syntaxin-6 as well as TBC1D4, a protein involved in the intracellular retention of Glut4 vesicles, also decreased by Nrg4 KD. Insulin failed to reduce autophagy in Nrg4 KD adipocytes, observed by a minor effect on mTOR phosphorylation, at the time that proteins involved in autophagy such as LC3-II, Rab11, and Clathrin were markedly upregulated. The lysosomal activity inhibitor bafilomycin A1 restored Glut4, IRAP, Syntaxin-6, and TBC1D4 content to those found in control adipocytes. Our study reveals that Nrg4 preserves the insulin responsiveness by preventing inflammation and, in turn, benefits the insulin regulation of autophagy.

Growing evidence implicates the gut microbiome in cognition. Blastocystis is a common gut single-cell eukaryote parasite frequently detected in humans but its potential involvement in human pathophysiology has been poorly characterized. Here we describe how the presence of Blastocystis in the gut microbiome was associated with deficits in executive function and altered gut bacterial composition in a discovery (n = 114) and replication cohorts (n = 942). We also found that Blastocystis was linked to bacterial functions related to aromatic amino acids metabolism and folate-mediated pyrimidine and one-carbon metabolism. Blastocystis-associated shifts in bacterial functionality translated into the circulating metabolome. Finally, we evaluated the effects of microbiota transplantation. Donor's Blastocystis subtypes led to altered recipient's mice cognitive function and prefrontal cortex gene expression. In summary, Blastocystis warrant further consideration as a novel actor in the gut microbiome-brain axis. This study was partially funded by the Catalan Government (AGAUR, #SGR2017-0734, ICREA Academia Award 2021) to J.M.F.-R., Instituto de Salud Carlos III (Madrid, Spain) through the projects PI15/01934, PI18/01022 and PI21/01361 to JMF-R, the project PI20/01090 (Co-funded by European Regional Development Fund “A way to make Europe”) to JM-P, and the project PI20/0155 to MP-O; the grants SAF2015-65878-R from Ministry of Economy and Competitiveness, Prometeo/2018/A/133 from Generalitat Valenciana, Spain and also by Fondo Europeo de Desarrollo Regional (FEDER) funds (“A way to build Europe”), European Commission (FP7), the Catalan Government (AGAUR, #SGR2017-669, ICREA Academia Award 2020 and Ministerio de Ciencia e Innovación PID2020- 120029GB-I00/MICIN/AEI/10.13039/501100011033, and RD21/0009/0019, European Commission-DG Research” (PainFact, H2020-SC1-2019-2-RTD-848099, QSPain Relief, H2020-SC1-2019-2-RTD-848068 to R.M.), the Spanish Instituto de Salud Carlos III (RTA, #RD16/0017/0020) and the European Regional Development Fund (project No. 01.2.2-LMT-K-718-02-0014) under grant agreement with the Research Council of Lithuania (LMTLT). We also acknowledge funding from the Spanish Ministry of Science, Innovation and Universities (RTI2018-099200-B-I00), and the Generalitat of Catalonia (Agency for Management of University and Research Grants (2017SGR696) and Department of Health (SLT002/16/00250)) to RP; María Arnoriaga-Rodríguez is funded by Instituto de Salud Carlos III, Río Hortega (CM19/00190). JM-P is funded by Instituto de Salud Carlos III through the Miguel Servet Program project CP18/00009 (Co-funded by the European Social Fund “Investing in your future”). MJ is a “Serra-Hunter” fellow.

Background: Thyroid hormone (TH) regulates metabolic pathways which may interfere with insulin action. There is limited knowledge on adipose tissue (AT) and skeletal muscle (SM) expression of genes...

Preadipocytes are crucial for healthy adipose tissue expansion. Preadipocyte differentiation is altered in obese individuals, which has been proposed to contribute to obesity-associated metabolic disturbances. Here, we aimed at identifying the pathogenic processes underlying impaired adipocyte differentiation in obese individuals with insulin resistance (IR)/type 2 diabetes (T2D). We report that down-regulation of a key member of the major spliceosome, PRFP8/PRP8, as observed in IR/T2D preadipocytes from subcutaneous (SC) fat, prevented adipogenesis by altering both the expression and splicing patterns of adipogenic transcription factors and lipid droplet-related proteins, while adipocyte differentiation was restored upon recovery of PRFP8/PRP8 normal levels. Adipocyte differentiation was also compromised under conditions of endoplasmic reticulum (ER)-associated protein degradation (ERAD) hyperactivation, as occurs in SC and omental (OM) preadipocytes in IR/T2D obesity. Thus, targeting mRNA splicing and ER proteostasis in preadipocytes could improve adipose tissue function and thus contribute to metabolic health in obese individuals.

Background: Obesity was consistently associated with a poor prognosis in patients with COVID-19. Epigenetic mechanisms were proposed as the link between obesity and comorbidities risk. Aim: To evaluate the methylation levels of angiotensin-converting enzyme 2 (ACE2) gene, the main entry receptor of SARS-CoV-2, in different depots of adipose tissue (AT) and leukocytes (PBMCs) in obesity and after weight loss therapy based on a very-low-calorie ketogenic diet (VLCKD), a balanced hypocaloric diet (HCD) or bariatric surgery (BS). Materials and Methods: DNA methylation levels of ACE2 were extracted from our data sets generated by the hybridization of subcutaneous (SAT) (n = 32) or visceral (VAT; n = 32) adipose tissue, and PBMCs (n = 34) samples in Infinium HumanMethylation450 BeadChips. Data were compared based on the degree of obesity and after 4–6 months of weight loss either by following a nutritional or surgical treatment and correlated with ACE2 transcript levels. Results: As compared with normal weight, VAT from patients with obesity showed higher ACE2 methylation levels. These differences were mirrored in PBMCs but not in SAT. The observed obesity-associated methylation of ACE2 was reversed after VLCKD and HCD but not after BS. Among the studied CpG sites, cg16734967 and cg21598868, located at the promoter, were the most affected and correlated with BMI. The observed DNA methylation pattern was inversely correlated with ACE2 expression. Conclusion: Obesity-related VAT shows hypermethylation and downregulation of the ACE2 gene that is mirrored in PBMCs and is restored after nutritional weight reduction therapy. The results warrant the necessity to further evaluate its implication for COVID-19 pathogenesis.