Biology subjects

Leech, T.

Publications and source records attributed to Leech, T..

3 recordsLinked to original sources

bioRxiv2026

A Wolbachia pipientis protein confers resistance to virus infection in Drosophila melanogaster

The intracellular bacterium Wolbachia pipientis alters the biology of its arthropod hosts in many ways, and can increase resistance to RNA viruses in both Drosophila and mosquitoes. Wolbachia-induced pathogen blocking has generated much interest because of its potential to restrict insect vector transmission of human diseases caused by RNA viruses. However, the molecular mechanisms by which Wolbachia affects host viral resistance are still mostly elusive. We used dilp2-3,5 mutant Drosophila, which are long-lived, but only in the presence of Wolbachia, to show that the presence of Wolbachia also increased the resistance of the mutant flies to infection with Drosophila C virus (DCV), relative both to mutants lacking Wolbachia and to wild type flies with and without Wolbachia. The insulin mutant flies had higher Wolbachia titres than wild type flies. By RNA-seq analysis of the Wolbachia transcriptome, we identified Wolbachia genes that were more strongly expressed in dilp2-3,5 mutant flies. Ankyrin-domain-containing proteins were among the most strongly up-regulated and they are predicted to be secreted effector proteins. To address their effect on host physiology, we generated 4 transgenic fly lines each with inducible expression of a different genes encoding ankyrin-domain-containing proteins. Expression of 3 of these did not cause obvious effects, but expression of WD0754 at high levels severely shortened fly survival. Interestingly, however, chronic low-level induction of WD0754 increased the resistance of the flies to DCV infection. Proteomics analysis showed a robust, tissue-specific, anti-viral response upon WD0754 induction, and identified the NFkB-like IMD pathway as a potential mediator of the antiviral activity of WD0754. Consistently, WD0754 expression activated Relish, a key downstream transcriptional mediator of IMD signalling, while loss-of Relish blocked the antiviral effect of WD0754. In summary, we identified a Wolbachia-derived ankyrin domain containing protein that modulates host immunity through the IMD pathway.

molecular biology↗

bioRxiv2022

Full geroprotection from brief rapamycin treatment by persistently increased intestinal autophagy

The licensed drug rapamycin has potential to be repurposed for geroprotection. A key challenge is to avoid adverse side-effects from continuous dosing regimes. Here we show a profound memory effect of brief, early rapamycin treatment of adults, which extended lifespan in Drosophila to the same degree as lifelong dosing. Lasting memory of earlier rapamycin treatment was mediated by elevated autophagy in enterocytes of the gut, accompanied by increased levels of intestinal lysosomal alpha-mannosidase V (LManV), proteins involved in branched-chain amino acid metabolism and lysozyme levels, and by maintained structure and function of the ageing intestine. Brief elevation of autophagy in early adulthood itself induced a long-term increase in autophagy. In mice, a short-term, 3-month treatment in early adulthood also induced a memory effect, with maintenance similar to that seen with chronic treatment, of lysozyme distribution, Man2B1 level in intestinal crypts, Paneth cell architecture and gut barrier function, even 6 months after rapamycin was withdrawn. The geroprotective effects of chronic rapamycin treatment can thus be obtained with a brief pulse of the drug in early adulthood.

physiology↗

bioRxiv2020

Social environment drives sex and age-specific variation in Drosophila melanogaster microbiome composition and predicted function.

Social environments influence multiple traits of individuals including immunity, stress and ageing, often in sex-specific ways. The composition of the microbiome (the assemblage of symbiotic microorganisms within a host) is determined by environmental factors and the hosts immune, endocrine and neural systems. The social environment could alter host microbiomes extrinsically by affecting transmission between individuals, likely promoting homogeneity in the microbiome of social partners. Alternatively, intrinsic effects arising from interactions between the microbiome and host physiology (the microbiota-gut-brain axis) could translate social stress into dysbiotic microbiomes, with consequences for host health. We investigated how manipulating social environments during larval and adult life-stages altered the microbiome composition of Drosophila melanogaster fruit flies. We used social contexts that particularly alter the development and lifespan of males, predicting that any intrinsic social effects on the microbiome would therefore be sex-specific. The presence of adult males during the larval stage significantly altered the microbiome of pupae of both sexes. In adults, same-sex grouping increased bacterial diversity in both sexes. Importantly, the microbiome community structure of males was more sensitive to social contact at older ages, an effect partially mitigated by housing focal males with young rather than co-aged groups. Functional analyses suggest that these microbiome changes impact ageing and immune responses. This is consistent with the hypothesis that the substantial effects of the social environment on individual health are mediated through intrinsic effects on the microbiome, and provides a model for understanding the mechanistic basis of the microbiota-gut-brain axis. Significance statementThe social environment has pervasive, multifaceted effects on individual health and fitness. If a hosts microbiome is sensitive to the social environment then it could be an important mediator of social effects, as the reciprocal relationships between hosts and their microbiomes have substantial implications for host health. Using a Drosophila melanogaster fruit fly model we show that the fly microbiome is sensitive to the social environment in a sex, age and life-stage dependent manner. In particular, older adult male microbiome communities are altered by same-sex social contact, but this depends on the age of the social partners. These changes have functional effects on fly immunity and lifespan, evidence that indeed this is an influential mediator of social effects on health.

ecology↗