Project description:TMAO is gut microbiota dependent metabolite catalyzed by monooxygenase FMO3 from TMA. TMAO is positively assocaited with different metabolic diseases such as diabetes, chronic kidney disease, and atherosclerosis. We used microarray to analyze the genes regulated by TMAO treatment in primary rat hepatocytes to further understand the mechanistic view of TMAO action.
Project description:To investigate the impact of TMAO on Myeloid cells. An RNA-seq analysis of myeloid cells was performed with and without TMAO treatment.
Project description:Trimethylamine-N-oxide (TMAO) is a uremic toxin, which has been associated with chronic kidney disease (CKD). Renal tubular epithelial cells play a central role in the pathophysiology of CKD. Megalin is an albumin-binding surface receptor on tubular epithelial cells, which is indispensable for urine protein reabsorption. To date, no studies have investigated the effect of TMAO on megalin expression and the functional properties of human tubular epithelial cells. The aim of this study was first to identify the functional effect of TMAO on human renal proximal tubular cells and second, to unravel the effects of TMAO on megalin-cubilin receptor expression. We found through global gene expression analysis that TMAO was associated with kidney disease. The microarray analysis also showed that megalin expression was suppressed by TMAO, which was also validated at the gene and protein level. High glucose and TMAO was shown to downregulate megalin expression and albumin uptake similarly. We also found that TMAO suppressed megalin expression via PI3K and ERK signaling. Furthermore, we showed that candesartan, dapagliflozin and enalaprilat counter-acted the suppressive effect of TMAO on megalin expression. Our results may further help us un-ravel the role of TMAO in CKD development and to identify new therapeutic targets to counteract TMAOs effects.
Project description:Circulating levels of the gut microbe-derived metabolite trimethylamine-N-oxide(TMAO) have recently been linked to cardiovascular disease (CVD) risk. Here we performed transcriptional profiling in mouse models of altered reverse cholesterol transport (RCT), and serendipitously identified the TMAO-generating enzyme flavin monooxygenase 3 (FMO3) as a powerful modifier of cholesterol metabolism and RCT. Knockdown of FMO3 in cholesterol-fed mice alters biliary lipid secretion, blunts intestinal cholesterol absorption, and limits the production of hepatic oxysterols and cholesteryl esters. Furthermore, FMO3 knockdown stimulates basal and liver X receptor (LXR)-stimulated macrophage RCT, thereby improving cholesterol balance. Conversely, FMO3 knockdown exacerbates hepatic ER stress and inflammation in part by decreasing hepatic oxysterol levels and subsequent LXR activation. FMO3 is thus identified as a central integrator of hepatic cholesterol and triacylglycerol metabolism, inflammation, and ER stress. These studies suggest that the gut microbiota-driven TMA/FMO3/TMAO pathway is a key regulator of lipid metabolism and inflammation. To identify potential regulators of macrophage reverse cholesterol transport (RCT), liver was isolated from two independent mouse models where the non-biliary RCT pathway known as transintestinal cholesterol excretion (TICE) was either chronically (NPC1L1-liver-transgenic mice) or acutely (ACAT2 antisense oligonucleotide treatment) stimulated. Total RNA was isolated and gene expression levels were profiled on the Affymetrix GeneAtlas MG-430 PM Array Strip (Affymetrix; Santa Clara, CA, USA)
Project description:Stroke is a kind of cerebrovascular disease with high mortality. TMAO has been shown to aggravate stroke outcomes, but its mechanism remains unclear. Mice were treated with TMAO in normal saline by oral gavage for 14 consecutive days. Then, mice were made into MCAO models. Neurological score, infarct volume, neuronal damage and markers associated with inflammation were assessed. Since microglia played a crucial role in stroke, microglia of MCAO mice were isolated for high-throughput sequencing to identify the most differentially expressed gene following TMAO treatment. Afterward, the downstream pathways of TMAO were investigated using primary microglia. Our results demonstrated that TMAO promoted the release of inflammatory cytokines in the brain of MCAO mice and promoted the activation of OGD/R microglial inflammasome, thereby exacerbating stroke outcomes. FTO/IGF2BP2 inhibited NLRP3 inflammasome activation in OGD/R microglia by downregulating the m6A level of NLRP3, TMAO can inhibit the expression of FTO and IGF2BP2, thus promoting the activation of NLRP3 inflammasome in OGD/R microglia. In conclusion, these results demonstrated that TMAO promotes NLRP3 inflammasome activation of microglia aggravating neurological injury in stroke through FTO/IGF2BP2.
Project description:Circulating trimethylamine N-oxide (TMAO) participates in the pathogenesis of cardio-metabolic diseases, with hepatic flavin-containing monooxygenase 3 (FMO3) originally regarded as the primary source of TMAO production. Here, we demonstrate that white adipose tissue (WAT) expressed FMO3 and its derived metabolic product TMAO causatively contribute to the systemic elevation of TMAO levels, WAT dysfunction, and metabolic diseases in ageing. We showed that FMO3 expression and TMAO levels are upregulated in WAT of naturally ageing animals and human subjects, as well as in a DNA damage-induced senescent adipocyte model, but not in the liver. This upregulation is due to p53 activation in mice and could be mitigated by calorie restriction in humans. Adipocyte-specific ablation of FMO3 attenuates TMAO accumulation in WAT and circulation, leading to enhanced glucose metabolism, energy homeostasis, and lipid regulation in aged and high-fat diet-induced obese mice. Transcriptomic and histological analysis link these metabolic improvements to reduced senescence, fibrosis, and inflammation in WAT as well as a decrease in adipose-resident macrophages. LiP-small molecule mapping (LiP-SMap) analysis identified numerous novel TMAO-interacting proteins implicated in inflammasome activation within white adipocytes and macrophages. Mechanistically, TMAO facilitates inflammasome activation by binding to the inflammasome adaptor protein apoptosis-associated speck-like protein containing A CARD (ASC), thereby inducing its expression, caspase-1 activation, and subsequent interleukin-1β (IL-1β) production. Our findings uncover a pivotal role for adipocyte FMO3 in modulating TMAO production and WAT dysfunction by promoting inflammasome activation in ageing via an autocrine and paracrine manner.
Project description:Purpose: The goals of this study were to identify preferential gene expression signatures that are unique to HAECs stimulated with the uremic toxin, TMAO, to accelerate vascular inflammation associated with chronic kidney diseases. Methods and results: HAECs were treated with TMAO (600 µM) for 18 hours, and RNAs were collected to generate mRNA transcription profiles. Transcriptional profiling revealed a unique TMAO stimulated HAECs relative to a non-stimulated control HAECs. Conclusion: Our study represents the first detailed analysis of TMAO treated HAECs transcriptome.
Project description:To investigate the mechanism how TMAO deteriorates cardiac dysfunction in murine left ventricular pressure overload model, we performed RNA-seq analysis with cardiac tissue from TMAO-treated mice.
Project description:Liver cancer has a high mortality rate. Chronic inflammation is one of the leading causes of hepatocellular carcinoma. Recent studies suggested high levels of trimethylamine N-oxide (TMAO) may correlate with increased risk of inflammatory-induced liver cancer. However, the mechanisms by which TMAO promotes liver cancer remain elusive. Here, we established a model of inflammatory-induced liver cancer by treating Hepa1-6 cells with TNF-α. TMAO synergistically increased the proliferation, migration and invasion of Hepa1-6 cells in the presence of TNF-α. We conducted bulk RNA-Seq of the TMAO-treated cell model of inflammatory Hepatocellular carcinoma (HCC)