Osteopontin Exacerbates High-Fat Diet-induced Metabolic Disorders in a microbiome-dependent Manner
Ontology highlight
ABSTRACT: Gut microbiota is involved in metabolic disorders. However, microbiome-based therapeutic interventions are not always effective, which might be due to interference of the host factors. Here, we first identified a strong positive correlation between OPN levels and BMI in humans. Next, we confirmed that OPN could aggravate high-fat diet induced metabolic disorders in mice. Importantly, we found that fecal microbiota transplantation from OPN-deficient mice significantly alleviated metabolic disorders in WT mice. OPN directly induces remodeling of the gut microbiota both in vitro and in vivo. These findings indicate that OPN could contribute to metabolic disorders by inducing an alteration of gut microbiota. OPN regulated the relative abundance of Lactobacillus by decreasing the adhesion of Lactobacillus to intestinal epithelial cells through Notch signaling pathway. These data identify OPN may serve as a potential pharmaceutical target for weight control and metabolic disorders treatment.
Project description:Depressive disorders often run in families, which, in addition to the genetic component, may point to the microbiome as a causative agent. Here, we employed a combination of behavioral, molecular and computational techniques to test the role of the microbiota in mediating despair behavior. In chronically stressed mice displaying despair behavior, we found that the microbiota composition and the metabolic signature dramatically change. Specifically, we observed reduced Lactobacillus and increased circulating kynurenine levels as the most prominent changes in stressed mice. Restoring intestinal Lactobacillus levels was sufficient to improve the metabolic alterations and behavioral abnormalities. Mechanistically, we identified that Lactobacillus-derived reactive oxygen species may suppress host kynurenine metabolism, by inhibiting the expression of the metabolizing enzyme, IDO1, in the intestine. Moreover, maintaining elevated kynurenine levels during Lactobacillus supplementation diminished the treatment benefits. Collectively, our data provide a mechanistic scenario for how a microbiota player (Lactobacillus) may contribute to regulating metabolism and resilience during stress.
Project description:Background: As a worldwide threat to mental health, depression affects about 322 million people globally. Recently, the role of gut microbiota dysbiosis on the pathogenesis of depression has received widespread attention, but the underlying mechanism remains elusive.Results: Corticosterone (CORT)-treated mice showed depressive-like behaviors, a reduction in hippocampal neurogenesis, and an altered composition of gut microbiota (GM). Fecal microbial transplantation (FMT) from CORT-treated mice transferred depressive-like phenotypes and their dominant GM, especially bifidobacterium and lactobacillus, to the recipients. Fecal metabolic profiling showed that the relative abundances of fecal ceramides were significantly increased in CORT-treated and the recipient mice. Metagenomic sequencing exposed that bifidobacterium and lactobacillus might be responsible for gut ceramides production in CORT-treated mice. We then found that treatment with ceramides via oral gavage was sufficient to recapitulate the depressive-like phenotypes in wild -type mice. Finally, RNA-sequencing data exposed that most of the differentially expressed genes (DEGs) between ceramides-treated mice and the control group were enriched in oxidative phosphorylation (OXPHOS) pathway. Conclusion: We conclude that chronic exposure to CORT leads to an altered GM composition and consequent ceramides production, thus leading to subtle mitochondrial OXPHOS dysfunction in hippocampus, which may contribute to the development of depressive disorders.
Project description:The indigenous human gut microbiota is a major contributor to the human superorganism with established roles in modulating nutritional status, immunity, and systemic health including diabetes and obesity. The complexity of the gut microbiota consisting of over 1012 residents and approximately 1000 species has thus far eluded systematic analyses of the precise effects of individual microbial residents on human health. In contrast, health benefits have been shown upon ingestion of certain so-called probiotic Lactobacillus strains in food products and nutritional supplements, thereby providing a unique opportunity to study the global responses of a gut-adapted microorganism in the human gut and to identify the molecular mechanisms underlying microbial modulation of intestinal physiology, which might involve alterations in the intestinal physico-chemical environment, modifications in the gut microbiota, and/or direct interaction with mucosal epithelia and immune cells. Here we show by transcriptome analysis using DNA microarrays that the established probiotic bacterium, L. plantarum 299v, adapts its metabolic capacity in the human digestive tract for carbohydrate acquisition and expression of exo-polysaccharide and proteinaceous cell surface compounds. This report constitutes the first application of global gene expression profiling of a gut-adapted commensal microorganism in the human gut. Comparisons of the transcript profiles to those obtained for L. plantarum WCFS1 in germ-free mice revealed conserved L. plantarum responses indicative of a core transcriptome expressed in the mammalian gut and provide new molecular targets for determining microbial-host interactions affecting human health. Hybridization of the samples against a common reference of gDNA isolated from L. plantarum 299v
Project description:Osteopontin (OPN) is a secreted glycoprotein, belonging to the non-structural extracellular matrix (ECM), and its over expression in human prostate cancer cells has been associated with disease progression, androgen independence and metastases. Nevertheless the pathophysiology of OPN in prostate tumorigenesis has never been studied. We crossed TRansgenic Adenocarcinoma of the Mouse Prostate (TRAMP) mice with OPN deficient (OPN-/-) mice and followed tumor onset and progression in these double mutants. Ultrasound examination detected the early onset of a spherical homogeneous tumor in about 60% of OPN-/- TRAMP mice that seldom occurs in parental TRAMP mice. Histology and immunohistochemistry characterized these tumors for being Tag positive but negative for AR, highly proliferative and endowed of neuroendocrine (NE) features. Gene expression profiling showed up-regulation of genes involved in tumor progression, cell cycle and neuronal differentiation in OPN-deficient versus -sufficient TRAMP tumors. Down-regulated genes included key genes of TGFï?¢ pathway, and a role for TGFï?¢ in NE differentiation of prostate cancer was also confirmed at the protein level. Furthermore, NE genes and particularly those characterizing early prostatic lesions of OPN-deficient mice were found to correlate with those of human NE tumours. These data underscore a novel role of OPN at early stages of prostate cancer growth, protecting against the development of aggressive NE tumors. Total RNA obtained from prostate tumors from 18 and 30 weeks old TRAMP mice, compared to RNA extracted from prostate tumors and prostate tissue from Osteopontin-deleted TRAMP mice
Project description:We define a pathogenic subset of microglia that is distinguished by expression of the CD11c protein and by production of osteopontin (OPN). OPN production by this CD11c+ microglial subset correlates positively with disease pathology and severity in the 5XFAD mouse model and in AD patients. Genetic ablation of OPN in 5XFAD mice leads to reduced development of pro-inflammatory CD11c+ microglia, increased amyloid beta (Aβ) phagocytosis and improved cognitive function.
Project description:Gut microbiota dysbiosis characterizes systemic metabolic alteration, yet its causality is debated. To address this issue, we transplanted antibiotic-free conventional wild-type mice with either dysbiotic (“obese”) or eubiotic (“lean”) gut microbiota and fed them either a NC or a 72%HFD. We report that, on NC, obese gut microbiota transplantation reduces hepatic gluconeogenesis with decreased hepatic PEPCK activity, compared to non-transplanted mice. Of note, this phenotype is blunted in conventional NOD2KO mice. By contrast, lean microbiota transplantation did not affect hepatic gluconeogenesis. In addition, obese microbiota transplantation changed both gut microbiota and microbiome of recipient mice. Interestingly, hepatic gluconeogenesis, PEPCK and G6Pase activity were reduced even once mice transplanted with the obese gut microbiota were fed a 72%HFD, together with reduced fed glycaemia and adiposity compared to non-transplanted mice. Notably, changes in gut microbiota and microbiome induced by the transplantation were still detectable on 72%HFD. Finally, we report that obese gut microbiota transplantation may impact on hepatic metabolism and even prevent HFD-increased hepatic gluconeogenesis. Our findings may provide a new vision of gut microbiota dysbiosis, useful for a better understanding of the aetiology of metabolic diseases. all livers are from NC-fed mice only.
Project description:Alterations in the tissue microenvironment collaborate with cell autonomous genetic changes to contribute to neoplastic progression. The importance of the microenvironment in neoplastic progression is underscored by studies demonstrating that fibroblasts isolated from a tumor stimulate the growth of preneoplastic and neoplastic cells in xenograft models. Similarly, senescent fibroblasts promote preneoplastic cell growth in vitro and in vivo. Because senescent cells accumulate with age, their presence is hypothesized to facilitate preneoplastic cell growth and tumor formation in older individuals. To identify senescent stromal factors directly responsible for stimulating preneoplastic cell growth, we carried out whole genome transcriptional profiling and compared senescent fibroblasts to their younger counterparts. We identified osteopontin (OPN) as one of the most highly elevated transcripts in senescent fibroblasts. Importantly, reduction of OPN protein levels by RNAi did not impact senescence induction in fibroblasts; however, it dramatically reduced the growth-promoting activities of senescent fibroblasts in vitro and in vivo, demonstrating that OPN is necessary for paracrine stimulation of preneoplastic cell growth. In addition, we found that recombinant OPN was sufficient to stimulate preneoplastic cell growth. Finally, we demonstrate that OPN is expressed in senescent stroma within preneoplastic lesions that arise following DMBA/TPA treatment of mice, suggesting that stromal-derived OPN-mediated signaling events impact neoplastic progression.
Project description:Microbial sequencing revealed progressive reduction of gut microbiota that showed some differences in the two ABX groups compared to untreated controls. Interestingly, duration of ABX was associated with a gradual disappearance of the CD4+ and CD4+CD8+ subset of gut intraepithelial lymphocytes (IELs). This IEL subset is microbiota-dependent and is absent in germ-free mice. Relative abundance of Lactobacillus reuteri correlated with frequencies of CD4+CD8+ IELs and reduced EAU. Notably, IELs in culture suppressed antigen-specific activation of autoreactive T cells.
Project description:The role of gut microbiota dysbiosis in systemic lupus erythematosus (SLE) pathogenesis remains elusive. Here, we show that fecal microbiota transplantation (FMT) from healthy mice to lupus mice ameliorated lupus-like symptoms. Microbiota reconstitution effectively reduced systemic class switch recombination and elevated IGH naïve isotype. Microbiota profiling revealed an enrichment of Lactobacillus johnsonii post-FMT, with a significant correlation to purine metabolites. Importantly, the Lactobacillus johnsonii-derived inosine, an intermediate metabolite in purine metabolism, effectively alleviated lupus-like symptoms by impeding B cell differentiation and reducing renal B cell infiltration. We further demonstrated that inosine reprograms B cells through the ERK-HIF-1α signaling pathway. Overall, our study highlights the discovery of a novel microbial metabolite modulating autoimmunity and suggests its potential for innovative microbiome-based therapeutic approaches.