Drosophila melanogasteris a powerful host model to study mycobacterial virulence

Abstract

Drosophila melanogaster (Drosophila), the common fruit fly, is one of the most extensively studied animal models we have, with a broad, advanced, and organized research community with tools and mutants readily available at low cost. Yet, Drosophila has barely been exploited to understand the underlying mechanisms of mycobacterial infections, including those caused by the top-killer pathogen Mycobacterium tuberculosis (Mtb). In this study, we aimed to investigate whether Drosophila is a suitable host model to study mycobacterial virulence, using Mycobacterium marinum (Mmar) to model mycobacterial pathogens. First, we validated that an established mycobacterial virulence factor, EccB1 of the ESX-1 Type VII secretion system, is required for Mmar growth within the flies. Second, we identified Mmar virulence factors in Drosophila in a high-throughput genome-wide manner using transposon insertion sequencing (TnSeq). Of the 181 identified virulence genes, the vast majority (91%) had orthologs in Mtb, suggesting that the encoded virulence mechanisms may be conserved across Mmar and Mtb. Finally, we validated one of the novel Mmar virulence genes we identified, a putative ATP-binding protein ABC transporter encoded by mmar_1660, as required for full virulence during both Drosophila and human macrophage infection. Together, our results show that Drosophila is a powerful host model to study and identify novel mycobacterial virulence factors relevant to human infection.

Massively parallel mutant selection identifies genetic determinants ofPseudomonas aeruginosacolonization ofDrosophila melanogaster

“…Studies of entomopathogens, such as Pseudomonas entomophila and Pectobacterium carotovora, and broad host-range pathogens, such as Serratia marcescens and Pseudomonas aeruginosa, have elucidated global mechanisms of gut homeostasis and host defense (3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Although comprehensive mutant analyses of Francisella novicida and Mycobacterium marinum demonstrate the potential of D. melanogaster as a host for forward genetic screens of bacterial pathogens, a genomewide screen of an ingested pathogen has not been reported (13,14). Recent advances in signature-tagged mutagenesis offer additional methods for a comprehensive genetic dissection of the fitness determinants that enable ingested bacteria to survive within the fly.…”

“…Comparison of genetic determinants of P. aeruginosa colonization in the fly and mouse from previous studies. (A)Alginate and psl polysaccharides, purines, pyrimidines, amino acids, cofactors, and respiration genes are critical for establishment of PAO1 and P. aeruginosa PA14 in invertebrate and vertebrate hosts, and at different body sites(14,31). (B) Mutants in aceA, and pilM were positively selected across systems, in both PAO1 and PA14.…”

Drosophila melanogaster as a Model to Study Fragile X-Associated Disorders

“…These advantages include a small body size (2-3 mm), easy and inexpensive cultivation and maintenance in the laboratory, a large number of offspring per mating (~100 eggs per day), and a rapid life cycle (about ten days at 25 • C) [1]. In addition, the fruit fly, D. melanogaster, is an excellent example of the 3R principle (Replacement, Refinement, Reduction), which replaces the use of higher laboratory animals in research studies [2]. The 3R principle is based on the belief that animal species have a certain degree of intrinsic value that must be considered in order to adequately consider animal welfare [3].…”