CONTEXT:Breast milk (BM) provides the optimal combination of essential nutrients and bioactive molecules for infant growth and development. However, accumulating evidence from our group and others indicates that maternal factors, such as obesity, can alter BM composition, potentially affecting offspring health outcomes. Bile acids (BA), both primary and secondary, have been identified in human BM but the precise composition and their role in BM remain largely underexplored. OBJECTIVE:In this study, we analyzed BA profiles in BM and plasma in lactating mothers with obesity or not, across 2 independent clinical cohorts. METHODS:BM and plasma samples were collected from breastfeeding women classified as normal weight (N) or with obesity (O). BA concentrations were quantified by reverse phase liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). RESULTS:BAs were present in BM, primarily as glyco- and tauro-conjugated of the primary BAs cholic (CA) and chenodeoxycholic acid (CDCA), although at lower levels than in plasma under normal-weight conditions. Maternal obesity led to a marked increase in total BM BA levels while plasma BA concentrations and composition remained unchanged. Additionally, BM BA levels were positively correlated with maternal pre-pregnancy body mass index, circulating leptin (a marker of adiposity), and insulin levels. CONCLUSION:Our findings identify maternal obesity as a significant modifier of BM BA composition, with potential implications for neonatal digestion, maturation, and health. Further research is warranted to elucidate the impact of these alterations on infant health and development.

BACKGROUND AND AIMS:Metabolic dysfunction-associated steatotic liver disease (MASLD), the most common chronic liver disease worldwide, is closely linked to obesity and metabolic syndrome. The reason some patients with MASLD develop metabolic dysfunction-associated steatohepatitis (MASH) and which metabolic changes in the liver are linked to its progression are unclear. METHODS:A non-targeted metabolomics analysis was performed on liver samples from 106 Finnish patients with severe obesity (71 females, mean age ± SD: 48.6 ± 8.7 years, body mass index: 41.6 ± 5.2 kg/m2) selected for laparoscopic gastric bypass surgery. Liver metabolomics and liver RNA sequencing data were used to study metabolic differences between those with steatosis and those with MASH. Validation was performed in a French cohort of 227 patients with obesity and MASLD. RESULTS:Overall, 45 metabolites differed between patients with steatosis and those with MASH. Novel MASH-associated metabolites included n-acetylneuraminate (β = 0.276), pentose acid (β = -0.290), UDP-galactose (β = -0.413), gamma/beta-tocopherol (β = -0.317), and guanidinosuccinate (β = -0.289) (all p < 0.05). In the validation cohort, 8 of 20 metabolites, including n-acetylneuraminate and plasmalogens 1-(1-enyl-palmitoyl)-2-arachidonoyl-GPE(P-16:0/20:4) and 1-(1-enyl-stearoyl)-2-arachidonoyl-GPE(P-18:0/20:4), were linked to MASH (p < 0.05). The 45 significantly altered metabolites formed two clusters with different associations with metabolic parameters, depending on their correlation with liver histological features. Kyoto Encyclopedia of Genes and Genomes analysis revealed that elevated metabolites in MASH were associated with inflammatory pathways; those decreased in MASH were linked to fatty acid degradation and amino acid and pyruvate metabolism. CONCLUSION:Transitioning from simple steatosis to MASH is associated with distinct alterations in liver metabolites and systemic metabolic traits, highlighting disease progression-associated pathways.

ABSTRACT Nuclear bile acid (BA) signaling plays a central role in liver homeostasis and represents a major therapeutic axis in fibrotic liver diseases. The farnesoid X receptor (FXR), a master nuclear effector of BA signaling, is expressed in several liver-resident cell types, suggesting that it may regulate distinct biological programs beyond the hepatocyte (HC) compartment. Using complementary pharmacological, genetic, and computational approaches across in vitro, ex vivo, and in vivo models of mouse and human origin, we investigated the role of hepatic stellate cell (HSC) FXR (FXR HSC ) in both unchallenged and injured livers, which has remained controversial. FXRα is robustly expressed in both HCs and HSCs with distinct isoform distributions, and these isoforms exhibited differential capacities to activate gene expression in an HSC context. We found that the potent selective FXR agonist tropifexor triggers a transcriptional program reminiscent of that observed after partial hepatectomy and associated with HC proliferation. This cell cycle-related response was also observed in HSCs and did not require intestinal FXR expression. An HSC-specific response to tropifexor was observed for several genes, including members of the glutathione-S-transferase (GST) family or Scube1 . FXR HSC was sufficient to observe the anti-fibrotic effects of tropifexor in precisioncut liver slices, an ex-vivo model of fibrosis. Finally, we identified the regulation of the chemerin-encoding gene Rarres2 as a relevant example of FXR HSC -dependent control of hepatic intercellular communication. Together, these findings identify FXR HSC as an important contributor to hepatic adaptation and therapeutic response to BA analogs and confirmed HSCs as a significant site of nuclear bile acid signaling in liver biology.

We developed a high-content screening to investigate how Alzheimer's disease (AD) genetic risk factors may affect synaptic mechanisms in rat primary neuronal cultures. Of the target genes identified, we found that Plcg2 downregulation in mouse dentate gyrus neurons consistently disrupted dendritic morphology and synaptic function. In human neuronal cultures (hNCs), PLCG2 downregulation also impaired synaptic function and increased amyloid-β (Aβ) levels and Tau phosphorylation. Very rare PLCG2 loss-of-function (LoF) variants were associated with a tenfold increased AD risk. PLCG2 LoF carriers show low mRNA/protein PLCG2/PLCγ2 levels and the R953* LoF mutation compromised synaptic function and increased AD hallmarks in hNCs. Single-nucleus RNA sequencing analyses confirmed that the downregulation of PLCG2 impacted pathways related to synaptic and neuronal functions, potentially through neurexins in neurons. In conclusion, PLCγ2 downregulation could increase AD risk by impairing synaptic functions and by increasing Aβ levels and Tau phosphorylation in neurons.

Defining the trajectory of cells during differentiation and disease is key for uncovering the mechanisms driving cell fate and identity. However, trajectories of human cells remain largely unexplored due to the challenges of studying them with human samples. In this study, we investigate the proteome trajectory of iPSCs differentiation to hepatic stellate cells (diHSCs) and identify RORA as a key transcription factor governing the metabolic reprogramming of HSCs necessary for diHSCs' commitment, identity, and activation. Using RORA deficient iPSCs and pharmacologic interventions, we show that RORA is required for early differentiation and prevents diHSCs activation by reducing the high energetic state of the cells. While RORA knockout mice have enhanced fibrosis, RORA agonists rescue multi-organ fibrosis in in vivo models. Notably, RORA expression correlates negatively with liver fibrosis and HSCs activation markers in patients with liver disease. This study reveals that RORA regulates cell metabolic plasticity, important for mesoderm differentiation, pericyte quiescence, and fibrosis, influencing cell commitment and disease.

Perfluorooctane sulfonate (PFOS) is a persistent and widespread contaminant found in the environment and, as a consequence, in the human body, and is linked to adverse health effects, including steatotic liver disease (SLD). Human studies on the role of PFOS in SLD have been largely epidemiological, relying on plasma without measuring liver PFOS. However, using plasma PFOS levels to evaluate fatty liver disease is not comprehensive, and the effects of PFOS in human liver have not been described. We investigated the association of PFOS in plasma (P-PFOS) and liver (L-PFOS) with clinical parameters of Metabolic dysfunction-Associated SLD (MASLD) in a large human cohort with obesity and histology-confirmed MASLD. Combining liver RNA-seq and metabolomic data from liver and plasma, we correlated L- and P-PFOS with mRNA transcripts and metabolites to identify dysregulated transcriptional and metabolic pathways. In women, L-PFOS negatively correlated with MASLD prevalence and severity. Conversely, in men, P-PFOS and L-PFOS positively associated with fibrosis. L-PFOS quartile analysis showed potential threshold effects in several histological parameters in men only. In women, L-PFOS negatively correlated with metabolites from pathways implicated in MASLD progression, including diacylglycerol and sphingolipid species. At the gene expression level, L-PFOS correlated negatively with many fibrosis-related genes involved in collagen formation and extracellular matrix organization in women only. Generally, L-PFOS correlated with many disease-relevant variables in women, but with few in men. These correlations in women were opposite the clinical and molecular changes seen in MASLD progression, while the positive correlation between L-PFOS and liver fibrosis in men suggests a positive relationship with liver disease.

Human milk oligosaccharides (HMOs) promote the development of the infant gut microbiota, notably through the growth of beneficial bacteria.

Coronavirus disease 2019 (COVID-19, caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2)) is primarily a respiratory illness. However, various extrapulmonary manifestations have been reported in patients with severe forms of COVID-19. Notably, SARS-CoV-2 was shown to directly trigger white adipose tissue (WAT) dysfunction, which in turn drives insulin resistance, dyslipidemia, and other adverse outcomes in patients with COVID-19. Although advanced age is the greatest risk factor for COVID-19 severity, published data on the impact of SARS-CoV-2 infection on WAT in aged individuals are scarce. Here, we characterized the response of subcutaneous and visceral WAT depots to SARS-CoV-2 infection in young adult and aged golden hamsters. In both age groups, infection was associated with a decrease in adipocyte size in the two WAT depots; this effect was partly due to changes in tissue's lipid metabolism and persisted for longer in aged hamsters than in young-adult hamsters. In contrast, only the subcutaneous WAT depot contained crown-like structures (CLSs) in which dead adipocytes were surrounded by SARS-CoV-2-infected macrophages, some of them forming syncytial multinucleated cells. Importantly, older age predisposed to a unique manifestation of viral disease in the subcutaneous WAT depot during SARS-CoV-2 infection; the persistence of very large CLSs was indicative of an age-associated defect in the clearance of dead adipocytes by macrophages. Moreover, we uncovered age-related differences in plasma lipid profiles during SARS-CoV-2 infection. These data suggest that the WAT's abnormal response to SARS-CoV-2 infection may contribute to the greater severity of COVID-19 observed in elderly patients.

Background: NAFLD affects nearly 25% of the global population. Cardiovascular disease (CVD) is the most common cause of death among patients with NAFLD, in line with highly prevalent dyslipidemia in this population. Increased plasma triglyceride (TG)‐rich lipoprotein (TRL) concentrations, an important risk factor for CVD, are closely linked with hepatic TG content. Therefore, it is of great interest to identify regulatory mechanisms of hepatic TRL production and remnant uptake in the setting of hepatic steatosis. Approach and Results: To identify liver‐regulated pathways linking intrahepatic and plasma TG metabolism, we performed transcriptomic analysis of liver biopsies from two independent cohorts of obese patients. Hepatic encoding apolipoprotein F (APOF) expression showed the fourth‐strongest negatively correlation with hepatic steatosis and the strongest negative correlation with plasma TG levels. The effects of adenoviral‐mediated human ApoF (hApoF) overexpression on plasma and hepatic TG were assessed in C57BL6/J mice. Surprisingly, hApoF overexpression increased both hepatic very low density lipoprotein (VLDL)‐TG secretion and hepatic lipoprotein remnant clearance, associated a ~25% reduction in plasma TG levels. Conversely, reducing endogenous ApoF expression reduced VLDL secretion in vivo, and reduced hepatocyte VLDL uptake by ~15% in vitro. Transcriptomic analysis of APOF‐overexpressing mouse livers revealed a gene signature related to enhanced ApoB‐lipoprotein clearance, including increased expression of Ldlr and Lrp1, among others. Conclusion: These data reveal a previously undescribed role for ApoF in the control of plasma and hepatic lipoprotein metabolism by favoring VLDL‐TG secretion and hepatic lipoprotein remnant particle clearance.

The APJ receptor and its two endogenous ligands, apelin and elabela, exert key roles in fetoplacental develop-ment. In adult, this system is altered by obesity but no data are available during pregnancy. We measured apelin and elabela levels in maternal plasma and cord blood and quantified placental gene expression of apelin, elabela and APJ in obese and non-obese mothers. We found that obesity reduced apelin level in cord blood without affecting maternal and cord blood elabela levels as well as placental gene expression of this system. Our data suggest that obesity alters fetal apelinemia in humans.

In 35 hospitalized depressed patients afternoon plasma cortisol (15:00-15:20 h) was measured in 3 ways: spontaneous, 2 h after administration of 45 mg oxazepam, and 16 h after administration of 2 mg dexamethasone. Dexamethasone and oxazepam caused a marked suppression of cortisol secretion, the former being the most pronounced. A significant correlation between spontaneous and suppressed cortisol levels was found and a correlation between the suppressed cortisol levels was also demonstrated. Both spontaneous and suppressed cortisol values correlated with measures of type (Newcastle scales) and severity (Hamilton rating scale) of depression, and the highest correlations were obtained with cortisol values after dexamethasone suppression. Analysis of the items of the Hamilton rating scale for depression showed a high correlation with retardation (items 7 + 8) and somatic complaints (items 12 + 13). A high correlation with the items 8 + 9 + 10 + 12, as found in an earlier study, was also found in this study. On the basis of these findings it is concluded that hypersecretion of cortisol measured spontaneously or after suppression is not a true diagnostic measure (within a group of depressed patients), but reflects differences in the intensity of certain psychiatric symptoms constituting the depressive syndrome.

OBJECTIVE:Recent evidence indicates that levels of breast milk (BM) hormones such as leptin can fluctuate with maternal adiposity, suggesting that BM hormones may signal maternal metabolic and nutritional environments to offspring during postnatal development. The hormone apelin is highly abundant in BM but its regulation during lactation is completely unknown. Here, we evaluated whether maternal obesity and overnutrition impacted BM apelin and leptin levels in clinical cohorts and lactating rats.METHODS:BM and plasma samples were collected from normal-weight and obese breastfeeding women, and from lactating rats fed a control or a high fat (HF) diet during lactation. Apelin and leptin levels were assayed by ELISA. Mammary gland (MG) apelin expression and its cellular localization in lactating rats was measured by quantitative RT-PCR and immunofluorescence, respectively.RESULTS:BM apelin levels increased with maternal BMI, whereas plasma apelin levels decreased. BM apelin was also positively correlated with maternal insulin and C-peptide levels. In rats, maternal HF feeding exclusively during lactation was sufficient to increase BM apelin levels and decrease its plasma concentration without changing body weight. In contrast, BM leptin levels increased with maternal BMI in humans, but did not change with maternal HF feeding during lactation in rats. Apelin is highly expressed in the rat MG during lactation and was mainly localized to mammary myoepithelial cells. We found that MG apelin gene expression was up-regulated by maternal HF diet and positively correlated with BM apelin content and maternal insulinemia.CONCLUSIONS:Our study indicates that BM apelin levels increase with long- and short-term overnutrition, possibly via maternal hyperinsulinemia and transcriptional upregulation of MG apelin expression in myoepithelial cells. Apelin regulates many physiological processes, including energy metabolism, digestive function, and development. Further studies are needed to unravel the consequences of such changes in offspring development.

Despite constant research and public policy efforts, the obesity epidemic continues to be a major public health threat, and new approaches are urgently needed. It has been shown that nutrient imbalance in early life, from conception to infancy, influences later obesity risk, suggesting that obesity could result from "developmental programming". In this review, we evaluate the possibility that early postnatal nutrition programs obesity risk via epigenetic mechanisms, especially DNA methylation, focusing on four main topics: (1) the dynamics of epigenetic processes in key metabolic organs during the early postnatal period; (2) the epigenetic effects of alterations in early postnatal nutrition in animal models or breastfeeding in humans; (3) current limitations and remaining outstanding questions in the field of epigenetic programming; (4) candidate pathways by which early postnatal nutrition could epigenetically program adult body weight set point. A particular focus will be given to the potential roles of breast milk fatty acids, neonatal metabolic and hormonal milieu, and gut microbiota. Understanding the mechanisms by which early postnatal nutrition can promote lifelong metabolic modifications is essential to design adequate recommendations and interventions to "de-program" the obesity epidemic.

OBJECTIVE:The lactation-suckling period is critical for white adipose tissue (WAT) development. Early postnatal nutrition influences later obesity risk but underlying mechanisms remain elusive. Here, we tested whether altered postnatal nutrition specifically during suckling impacts epigenetic regulation of key metabolic genes in WAT and alter long-term adiposity set point.METHODS:We analyzed the effects of maternal high-fat (HF) feeding in rats exclusively during lactation-suckling on breast milk composition and its impact on male offspring visceral epidydimal (eWAT) and subcutaneous inguinal (iWAT) depots during suckling and in adulthood.RESULTS:Maternal HF feeding during lactation had no effect on mothers' body weight (BW) or global breast milk composition, but induced qualitative changes in breast milk fatty acid (FA) composition (high n-6/n-3 polyunsaturated FA ratio and low medium-chain FA content). During suckling, HF neonates showed increased BW and mass of both eWAT and iWAT depot but only eWAT displayed an enhanced adipogenic transcriptional signature. In adulthood, HF offspring were predisposed to weight gain and showed increased hyperplastic growth only in eWAT. This specific eWAT expansion was associated with increased expression and activity of stearoyl-CoA desaturase-1 (SCD1), a key enzyme of FA metabolism. SCD1 converts saturated FAs, e.g. palmitate and stearate, to monounsaturated FAs, palmitoleate and oleate, which are the predominant substrates for triglyceride synthesis. Scd1 upregulation in eWAT was associated with reduced DNA methylation in Scd1 promoter surrounding a PPARγ-binding region. Conversely, changes in SCD1 levels and methylation were not observed in iWAT, coherent with a depot-specific programming.CONCLUSIONS:Our data reveal that maternal HF feeding during suckling programs long-term eWAT expansion in part by SCD1 epigenetic reprogramming. This programming events occurred with drastic changes in breast milk FA composition, suggesting that dietary FAs are key metabolic programming factors in the early postnatal period.

Pregnancy is a dynamic and precisely organized process during which one or more baby develops. Embryonic development relies on the formation of the placenta, allowing nutrient and oxygen exchange between the mother and the fetus. Dysfunction of placental formation lead to pregnancy disorders such as preeclampsia (PE) with serious deleterious consequences for fetal and maternal health. Identifying factors involved in fetoplacental homeostasis could inform better diagnostic and therapeutic strategies for these pathological pregnancies. Here, we summarize actions of elabela, apelin and their common receptor APJ in the fetoplacental unit. Studies indicate that elabela is crucial for embryo cardiovascular system formation and early placental development, while apelin acts in mid/late gestation to modulate fetal angiogenesis and energy homeostasis. Most of these findings, drawn from animal models, indicate a key role of elabela/apelin-APJ system in the fetoplacental unit. This review also provides an overview of clinical studies investigating elabela/apelin-APJ system in pathological complicated pregnancies such as PE and gestational diabetes mellitus (GDM). While elabela-deficient mice display all the features of PE, current clinical studies show no difference in circulating elabela levels between PE and control patients which does not support a role in PE development. Conversely, apelin levels are increased during PE, but the use of apelin as an early PE marker remains to be fully investigated.

According to the Developmental Origin of Health and Disease (DOHaD) concept, maternal obesity and accelerated growth in neonates program obesity later in life. White adipose tissue (WAT) has been the focus of developmental programming events, although underlying mechanisms remain elusive. In rodents, WAT development primarily occurs during lactation. We previously reported that adult rat offspring from dams fed a high-fat (HF) diet exhibited fat accumulation and decreased peroxisome proliferator-activated receptor γ (PPARγ) mRNA levels in WAT. We hypothesized that PPARγ down-regulation occurs via epigenetic malprogramming which takes place during adipogenesis. We therefore examined epigenetic modifications in the PPARγ1 and PPARγ2 promoters in perirenal (pWAT) and inguinal fat pads of HF offspring at weaning (postnatal d 21) and in adulthood. Postnatal d 21 is a period characterized by active epigenomic remodeling in the PPARγ2 promoter (DNA hypermethylation and depletion in active histone modification H3ac and H3K4me3) in pWAT, consistent with increased DNA methyltransferase and DNA methylation activities. Adult HF offspring exhibited sustained hypermethylation and histone modification H3ac of the PPARγ2 promoter in both deposits, correlated with persistent decreased PPARγ2 mRNA levels. Consistent with the DOHaD hypothesis, retained epigenetic marks provide a mechanistic basis for the cellular memory linking maternal obesity to a predisposition for later adiposity.-Lecoutre, S., Pourpe, C., Butruille, L., Marousez, L., Laborie, C., Guinez, C., Lesage, J., Vieau, D., Eeckhoute, J., Gabory, A., Oger, F., Eberlé, D., Breton, C. Reduced PPARγ2 expression in adipose tissue of male rat offspring from obese dams is associated with epigenetic modifications.

Background and aims: Progranulin is a circulating protein that modulates inflammation and is found in atherosclerotic lesions. Here we determined whether inflammatory cell-derived progranulin impacts atherosclerosis development. Methods: Ldlr(-/-) mice were transplanted with bone marrow from wild-type (WT) or Grn(-/-)(progranulin KO) mice (referred to as Tx-WT and Tx-KO, respectively). Results: After 10 weeks of high-fat diet feeding, both groups displayed similarly elevated plasma levels of cholesterol and triglycerides. Despite abundant circulating levels of progranulin, the size of atherosclerotic lesions in TxKO mice was increased by 47% in aortic roots and by 62% in whole aortas. Aortic root lesions in Tx-KO mice had increased macrophage content and larger necrotic cores, consistent with more advanced lesions. Progranulin staining was markedly reduced in the lesions of Tx-KO mice, indicating little or no uptake of circulating progranulin. Mechanistically, cultured progranulin-deficient macrophages exhibited increased lysosome-mediated exophagy of aggregated low-density lipoproteins resulting in increased cholesterol uptake and foam cell formation. Conclusions: We conclude that hematopoietic progranulin deficiency promotes diet-induced atherosclerosis in Ldlr(-/-) mice, possibly due to increased exophagy-mediated cholesterol uptake. Circulating progranulin was unable to prevent the increased lesion development, consistent with the importance of progranulin acting via cell-autonomous or local effects.

Objective: According to the Developmental Origin of Health and Disease (DOHaD) concept, maternal obesity and accelerated growth in neonates predispose offspring to white adipose tissue (WAT) accumulation. In rodents, adipogenesis mainly develops during lactation. The mechanisms underlying the phenomenon known as developmental programming remain elusive. We previously reported that adult rat offspring from high-fat diet-fed dams (called HF) exhibited hypertrophic adipocyte, hyperleptinemia and increased leptin mRNA levels in a depot-specific manner. We hypothesized that leptin upregulation occurs via epigenetic malprogramming, which takes place early during development of WAT. Methods: As a first step, we identified in silico two potential enhancers located upstream and downstream of the leptin transcription start site that exhibit strong dynamic epigenomic remodeling during adipocyte differentiation. We then focused on epigenetic modifications (methylation, hydroxymethylation, and histone modifications) of the promoter and the two potential enhancers regulating leptin gene expression in perirenal (pWAT) and inguinal (iWAT) fat pads of HF offspring during lactation (postnatal days 12 (PND12) and 21 (PND21)) and in adulthood. Results: PND12 is an active period for epigenomic remodeling in both deposits especially in the upstream enhancer, consistent with leptin gene induction during adipogenesis. Unlike iWAT, some of these epigenetic marks were still observable in pWAT of weaned HF offspring. Retained marks were only visible in pWAT of 9-month-old HF rats that showed a persistent “expandable” phenotype. Conclusions: Consistent with the DOHaD hypothesis, persistent epigenetic remodeling occurs at regulatory regions especially within intergenic sequences, linked to higher leptin gene expression in adult HF offspring in a depot-specific manner.