Is there a link between aging and microbiome diversity in exceptional mammalian longevity?

Graham M Hughes,Emma C Teeling,John Leech,Jose V Lopez,Sébastien J Puechmaille

doi:10.7717/peerj.4174

Graham M Hughes, Emma C Teeling + Show 3 more

Open Access

https://doi.org/10.7717/peerj.4174

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Abstract

A changing microbiome has been linked to biological aging in mice and humans, suggesting a possible role of gut flora in pathogenic aging phenotypes. Many bat species have exceptional longevity given their body size and some can live up to ten times longer than expected with little signs of aging. This study explores the anal microbiome of the exceptionally long-lived Myotis myotis bat, investigating bacterial composition in both adult and juvenile bats to determine if the microbiome changes with age in a wild, long-lived non-model organism, using non-lethal sampling. The anal microbiome was sequenced using metabarcoding in more than 50 individuals, finding no significant difference between the composition of juvenile and adult bats, suggesting that age-related microbial shifts previously observed in other mammals may not be present in Myotis myotis. Functional gene categories, inferred from metabarcoding data, expressed in the M. myotis microbiome were categorized identifying pathways involved in metabolism, DNA repair and oxidative phosphorylation. We highlight an abundance of ‘Proteobacteria’ relative to other mammals, with similar patterns compared to other bat microbiomes. Our results suggest that M. myotis may have a relatively stable, unchanging microbiome playing a role in their extended ‘health spans’ with the advancement of age, and suggest a potential link between microbiome and sustained, powered flight.

Highlights

The importance of the gut microbiome, the collection of microflora or microbiota inhabiting various regions of the gastro-intestinal tract, has become apparent in recent years
We find that the highest number of pathways expressed in bat metagenomes are involved in metabolism, energy consumption, DNA repair and oxidative phosphorylation, all reactions that may play a role in the use of powered flight and aging, suggesting a potential interaction between long-term microbiome stability, lifespan and powered flight
Previous studies investigating the role of the microbiome in aging have focused on human and mice samples, and have demonstrated correlations between microbial changes and a pathogenic aging phenotype

Summary

Introduction

The importance of the gut microbiome, the collection of microflora or microbiota inhabiting various regions of the gastro-intestinal tract, has become apparent in recent years. A reduction of lactobacilli and an increase of potentially pathogenic Enterobacteriaceae have been observed in frail individuals (Van Tongeren et al, 2005) This accumulation of pathogenic flora has been associated with a range of clinical problems such as infection, cancer and deficiencies in immune response (Atarashi et al, 2013; Saraswati & Sitaraman, 2015). Similar microbial shifts are observed in mice, such as the decrease in bacteria that synthesize vitamin B12 in older age cohorts, leading to overall changes in microbiome composition and function in age related frailty (Langille et al, 2014) implying a general trend in the aging gut. The question of whether or not such microbial shifts are a symptom rather than a driver of aging has yet to be conclusively answered

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