The intestinal microbiota contributes to the development of immune-mediated cardiovascular inflammation and vasculitis in mice.

Alterations in the intestinal microbiota contribute to the pathogenesis of various cardiovascular disorders, but how they affect the development of Kawasaki disease (KD), an acute pediatric vasculitis, remains unclear. We report that depleting the gut microbiota reduces the development of cardiovascular inflammation in a murine model mimicking KD vasculitis. The development of cardiovascular lesions was associated with alterations in the intestinal microbiota composition and, notably, a decreased abundance of Akkermansia muciniphila and Faecalibacterium prausnitzii. Oral supplementation with either of these live or pasteurized individual bacteria, or with short-chain fatty acids (SCFAs) produced by them, attenuated cardiovascular inflammation. Treatment with Amuc_1100, the TLR-2 signaling outer membrane protein from A. muciniphila , also decreased the severity of vascular inflammation. This study reveals an underappreciated gut microbiota-cardiovascular inflammation axis in KD vasculitis pathogenesis and identifies specific intestinal commensals that regulate vasculitis in mice by producing metabolites or via extracellular proteins acting on gut barrier function. IN BRIEF: It remains unclear whether changes in the intestinal microbiota composition are involved in the development of cardiovascular lesions associated with Kawasaki disease (KD), an immune-mediated vasculitis. Jena et al. observe alterations in the intestinal microbiota composition of mice developing vasculitis, characterized by reduced A. muciniphila and F. prausnitzii . Oral supplementation with either of these bacteria, live or pasteurized, or with bacteria-produced short-chain fatty acids (SCFAs) or Amuc_1100, the TLR-2 signaling outer membrane protein of A. muciniphila , was sufficient to alleviate the development of cardiovascular lesions in mice by promoting intestinal barrier function. HIGHLIGHTS: Absence or depletion of the microbiota decreases the severity of vasculitis in a murine model mimicking KD vasculitis. Supplementation of B. wadsworthia and B. fragilis promotes murine KD vasculitis. Decreased abundances of F. prausnitzii and A. muciniphila are associated with the development of cardiovascular lesions in mice. Supplementation with either live or pasteurized A. muciniphila and F. prausnitzii, or the TLR-2 signaling Amuc_1100, reduces the severity of vasculitis by promoting gut barrier function.

The essential roles of FXR in diet and age influenced metabolic changes and liver disease development: a multi-omics study.

BACKGROUND: Aging and diet are risks for metabolic diseases. Bile acid receptor farnesoid X receptor (FXR) knockout (KO) mice develop metabolic liver diseases that progress into cancer as they age, which is accelerated by Western diet (WD) intake. The current study uncovers the molecular signatures for diet and age-linked metabolic liver disease development in an FXR-dependent manner. METHODS: Wild-type (WT) and FXR KO male mice, either on a healthy control diet (CD) or a WD, were euthanized at the ages of 5, 10, or 15 months. Hepatic transcriptomics, liver, serum, and urine metabolomics as well as microbiota were profiled. RESULTS: WD intake facilitated hepatic aging in WT mice. In an FXR-dependent manner, increased inflammation and reduced oxidative phosphorylation were the primary pathways affected by WD and aging. FXR has a role in modulating inflammation and B cell-mediated humoral immunity which was enhanced by aging. Moreover, FXR dictated neuron differentiation, muscle contraction, and cytoskeleton organization in addition to metabolism. There were 654 transcripts commonly altered by diets, ages, and FXR KO, and 76 of them were differentially expressed in human hepatocellular carcinoma (HCC) and healthy livers. Urine metabolites differentiated dietary effects in both genotypes, and serum metabolites clearly separated ages irrespective of diets. Aging and FXR KO commonly affected amino acid metabolism and TCA cycle. Moreover, FXR is essential for colonization of age-related gut microbes. Integrated analyses uncovered metabolites and bacteria linked with hepatic transcripts affected by WD intake, aging, and FXR KO as well as related to HCC patient survival. CONCLUSION: FXR is a target to prevent diet or age-associated metabolic disease. The uncovered metabolites and microbes can be diagnostic markers for metabolic disease.

Western Diet-Induced Dysbiosis in Farnesoid X Receptor Knockout Mice Causes Persistent Hepatic Inflammation after Antibiotic Treatment.

Patients who have liver cirrhosis and liver cancer also have reduced farnesoid X receptor (FXR). The current study analyzes the effect of diet through microbiota that affect hepatic inflammation in FXR knockout (KO) mice. Wild-type and FXR KO mice were on a control (CD) or Western diet (WD) for 10 months. In addition, both CD- and WD-fed FXR KO male mice, which had hepatic lymphocyte and neutrophil infiltration, were treated by vancomycin, polymyxin B, and Abx (ampicillin, neomycin, metronidazole, and vancomycin). Mice were subjected to morphological analysis as well as gut microbiota and bile acid profiling. Male WD-fed FXR KO mice had the most severe steatohepatitis. FXR KO also had reduced Firmicutes and increased Proteobacteria, which could be reversed by Abx. In addition, Abx eliminated hepatic neutrophils and lymphocytes in CD-fed, but not WD-fed, FXR KO mice. Proteobacteria and Bacteroidetes persisted in WD-fed FXR KO mice even after Abx treatment. Only polymyxin B could reduce hepatic lymphocytes in WD-fed FXR KO mice. The reduced hepatic inflammation by antibiotics was accompanied by decreased free and conjugated secondary bile acids as well as changes in gut microbiota. Our data revealed that Lactococcus, Lactobacillus, and Coprococcus protect the liver from inflammation.

Co-activator binding protein PIMT mediates TNF-α induced insulin resistance in skeletal muscle via the transcriptional down-regulation of MEF2A and GLUT4.

The mechanisms underlying inflammation induced insulin resistance are poorly understood. Here, we report that the expression of PIMT, a transcriptional co-activator binding protein, was up-regulated in the soleus muscle of high sucrose diet (HSD) induced insulin resistant rats and TNF-α exposed cultured myoblasts. Moreover, TNF-α induced phosphorylation of PIMT at the ERK1/2 target site Ser(298). Wild type (WT) PIMT or phospho-mimic Ser298Asp mutant but not phospho-deficient Ser298Ala PIMT mutant abrogated insulin stimulated glucose uptake by L6 myotubes and neonatal rat skeletal myoblasts. Whereas, PIMT knock down relieved TNF-α inhibited insulin signaling. Mechanistic analysis revealed that PIMT differentially regulated the expression of GLUT4, MEF2A, PGC-1α and HDAC5 in cultured cells and skeletal muscle of Wistar rats. Further characterization showed that PIMT was recruited to GLUT4, MEF2A and HDAC5 promoters and overexpression of PIMT abolished the activity of WT but not MEF2A binding defective mutant GLUT4 promoter. Collectively, we conclude that PIMT mediates TNF-α induced insulin resistance at the skeletal muscle via the transcriptional modulation of GLUT4, MEF2A, PGC-1α and HDAC5 genes.

Layered inorganic nanocomposites: a promising carrier for 5-fluorouracil (5-FU).

We report here the intercalation of 5-fluorouracil (5-FU), an anticancer drug in interlayer gallery of Na(+) clay (Montmorillonite, MMT), with the assistance of biopolymer (chitosan, CS). The X-ray diffraction patterns, thermal and spectroscopic analyses indicated the drug intercalation into the clay interlayer space in support of CS and stabilized in the longitudinal monolayer by electrostatic interaction. In vitro drug release showed controlled release pattern. The genotoxic effect of drug was in vitro evaluated in human lymphocyte cell culture by comet assay, and results indicated significant reduction in DNA damage when drug was intercalated with clay and formulated in composites. The results of in vitro cell viability assay in cancer cells pointed at decreased toxicity of drug when encapsulated in Na(+)-clay plates than the pristine drug. In vivo pharmacokinetics, biodistribution, hepatotoxicity markers, e.g., SGPT and SGOT, and liver/testicular histology in rats showed plasma/tissue drug levels were within therapeutic window as compared to pristine drug. Therefore, drug-clay hybrid and composites can be of considerable value in chemotherapy of cancer with reduced side effects.