Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Diabetes. Aug 10, 2016; 7(15): 316-320
Published online Aug 10, 2016. doi: 10.4239/wjd.v7.i15.316
Increased fecal viral content associated with obesity in mice
Hariom Yadav, Shalini Jain, Ravinder Nagpal, Francesco Marotta
Hariom Yadav, Department of Nutritional Biotechnology, National Agri-Food Biotechnology Institute, Mohali, Punjab 160071, India
Shalini Jain, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
Ravinder Nagpal, Probiotics Research Laboratory, Juntendo University Graduate School of Medicine, Tokyo 1138421, Japan
Francesco Marotta, ReGenera Research group for Aging Intervention and Milano Medical, Gender Healthy Aging Unit by Genomics, 20122 Milano, Italy
Author contributions: Yadav H and Jain S performed majority of experiments, analyzed data and wrote manuscripts; Nagpal R and Marotta F participated significantly on study design and coordination for data analysis and interpretations, as well as writing manuscript.
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by Institutional Animal Care and Use Committee of the Punjab University, and PGIMER, Chandigarh.
Conflict-of-interest statement: No conflict of interest exists for this study.
Data sharing statement: Data will be readily available on request.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Hariom Yadav, PhD, Scientist, Ramalingaswami Fellow, Department of Nutritional Biotechnology, National Agri-Food Biotechnology Institute, C-127, Industrial Area, Phase 8, Mohali, Punjab 160071, India. yadavhariom@gmail.com
Telephone: +91-301-496459 Fax: +91-301-4514800
Received: March 17, 2016
Peer-review started: March 18, 2016
First decision: May 19, 2016
Revised: May 26, 2016
Accepted: July 11, 2016
Article in press: July 13, 2016
Published online: August 10, 2016
Abstract

AIM: To investigate the presence of total gut viral content in obese mice, and establish correlation with obesity associated metabolic measures and gut microbiome.

METHODS: Fresh fecal samples were collected from normal and obese (Leptin deficient: Lepob/ob) mice. Total viral DNA and RNA was isolated and quantified for establishing the correlation with metabolic measures and composition of gut bacterial communities.

RESULTS: In this report, we found that obese mice feces have higher viral contents in terms of total viral DNA and RNA (P < 0.001). Interestingly, these increased viral DNA and RNA content were tightly correlated with metabolic measures, i.e., body weight, fat mass and fasting blood glucose. Total viral content were positively correlated with firmicutes (R2 > 0.6), whilst negatively correlated with bacteroidetes and bifidobacteria.

CONCLUSION: This study suggests the strong correlation of increased viral population into the gut of obese mice and opens new avenues to explore the role of gut virome in pathophysiology of obesity.

Keywords: Obesity, Gut, Microbiome, Virome, DNA, RNA, Virus, Fat mass

Core tip: Gut microbiome is known for major constituents of bacterial population, and their association with obesity, but microbes like viruses are majorly neglected. Our investigation on the basis of hypothesis that viruses are an important part of microbial world, and found in substantial numbers into human gut, we investigated whether viral content have any correlation with obesity in mice models. Interestingly, we found that DNA and RNA viral fecal content was significantly increased in obese mice as compared to normal. This suggests that viral population may have role to regulate host metabolism and might impact obesity prevalence via alteration of gut microbiome composition. Our findings open a new area of research to explore the role of gut virome in obesity.