Effect Of Capsaicin On Intestinal Flora Of High Fat Diet Induced Obese Mice

Background: Obesity is a global problem that affects human health.Obesity can aggravate human physical and psychological risks,such as metabolic syndrome.Diet intervention and physical exercise are the main ways to treat obesity.In recent years,several bio-molecules from diets have been shown to have the effect of weight loss,including capsaicin,fructooligosaccharide,and polyphenols.Chilli or hot pepper is widely used as a vegetable or seasoning in the world,and its main ingredient capsaicin has been widely reported in human and animal for function of anti-obesity.The anti-obesity mechanisms of capsaicin are complicated,including the body's metabolic regulation,reduced food intake and so on.Studies found that capsaicin activates the transient receptor potential vanilloid subtype 1(TRPV1)calcium channel and enhances the secretion of catecholamines in the adrenal medulla,thereby enhancing the heat effect to reduce weight gain.Studies found that capsaicin can reduce food intake,and this effect depends on TRPV1.There is growing evidence that the disfunction of microbial ecology of intestinal microbes plays an important role in obesity and other metabolic syndromes.There are a large number of physiological and pathological interactions between intestinal microbes and hosts,such as regulation of host energy balance,glucose metabolism,and chronic inflammatory state.Studies found that obesity and obese mice in the intestinal microbial community composition has undergone tremendous changes.The anti-obesity of capsaicin by TRPV1 has been extensively studied,but the effect of capsaicin on intestinal microflora has not been systematically reported.In microbial community analysis,based on amplicon sequencing of 16 S r RNA gene or shotgun metagenom sequencing,the bioinformatics analysis process involves many softwares,includes large number of steps,including sequencing raw data quality control,debarcdeing,format conversion and so on.How to complete these analytical steps accurately and efficiently is an urgent problem that bioinformatics analysts and developers need to solve.Object: To study the association between capsaicin and intestinal flora of high fat diet induced obese mice,and to explore the mechanism of capsaicin on changing the structure of intestinal flora based on one or more intestinal microbes.To design and develop microbial community analysis tools.Methods and Results: This study consists of three parts:Part 1: Study the association between capsaicin and intestinal flora of high fat diet induced obese mice.After studing the changes of intestinal microflora between obese C57BL/6J mice and obese mice fed with capsaicin after 9 weeks,results show that the anti-obesity effect of capsaicin was related to the change of intestinal microbial community.1.For the microbial community composition,at the phylum level,the abundance of phylum Proteobacteria was significantly reduced in intestinal flora of high fat diet induced mice with long-term consumption of capsaicin.At the genus level,the abundance of Bacteroides,Coprococcus,Prevotella and Akkermansia increased significantly,and the increasing abundance of these bacteria are good for health.2.For the microbial community function,the abundance of Parkinson's disease-related metabolic pathways and bacterial virulence-related type IV secretion system metabolic module decreased.And the abundance of Glycolysis(Embden-Meyerhof pathway)metabolic module increases,which is conducive to improving the host glucose metabolism.Part 2: Study on abundance increasing mechanism of Akkermansia muciniphila by capsaicin treatment1.Direct stimulation on A.muciniphila by capsaicin results show that capsaicin at high concentration inhibit the growth of A.muciniphila.While low concentration of capsaicin does not promote its growth.And A.muciniphila grows faster and plateaued at a higher cell density with the addition of mucin in the culture medium.2.Feeding high fat diet induced obese mice fed with capsaicin after 9 weeks did not increase the number and density of intestinal goblet cells compared with mice without capsaicin treatment.3.The expression of Muc2 in the jujunum goblet cells was up-regulated for 90 minutes,and the expression of Reg3 g gene in the colon was increased steadily in the C57 BL / 6J mice.Part 3: Design and development of microbial community analysis toolkitTo reach the reproducibility,diversity and efficiency requirements of microbial community analysis,four microbial community analysis toolkits were developed using the Go language.They provide single-executable binary files for most popular operating systems such as Windows,Linux,OS X,Free BSD,Open BSD,and there's no need to install and configure.Users can just download the tarballs,decompress and immediately use,which makes the microbial flora and bioinformatics analysis easier and more efficient.1,Designing and developing highly optimized FASTA/Q sequence processing software toolkit Seq Kit,which provides 20 practical subcommands and rich documentation to improve the processing efficiency of sequencing data.2.Designing and developing the CSV/TSV format processing toolkit csvtk,which provides 25 easy-to-use and practical subcommands for handling CSV/TSV data files in microbial community analysis.3,Designing and developing NCBI taxonomy data processing toolkit Taxon Kit for efficient query,conversion of NCBI taxonomy data to deal with different microbial community analysis software format requirements.4,Designing and developing job parallel software “rush”,which provides functions of high practicality.Rush can simplify and accelerate the processing of a large number of samples containing microbial community analysis and other bioinformatic analysis.Conclusions:1.Capsaicin treatment reduces body weight and improves glucose homeostasis in HFD mice.This effect was associated with a modest modulation of gut microbiome.The changes in the gut microbiome and the increase in Akkermansia population might play a key role in this protective effect.Thus,we propose that capsaicin may prevent obesity through modulation of the gut microbiota?2.The possible mechanisms of increased A.muciniphila by capsaicin include:(1)Capsaicin stimulates goblet cells to secrete more mucin to provide more food sources,so that the absolute abundance of A.muciniphila increases;(2)Antimicrobial protein Reg3 g expression upgrades,which suppress the growing of others microbioal organisms and the relative abundance of A.muciniphila increases.(3)Food intake in mice reduced caused by spicy and hot capsaicin.However,A.muciniphila can utilize mucin as the only nitrogen and carbon source,so it's not affected by reduced food intake and the relative abundance increases.3.In this study,we developed serveral cross-platform,easy-to-use,practical and efficient microbial community analysis softwares to meet the requirements of repeatability,diversity and high efficiency of microbial community analysis and to meet the growing demand for sequencing big data.FASTA/Q format processing tools Seq Kit,CSV/TSV format processing software toolkit csvtk,NCBI taxonomy toolkit Taxon Kit and job parallel software rush can greatly improve the efficiency of microbiological and bioinformatics analysis,simplify and accelerate analysis containing a large number of samples.And the tools are welcome by many users in bioinformatics and open source community.