[
International Worm Meeting,
2019]
Mitochondria are essential double membrane organelles responsible for almost 95% of cellular metabolic energy. However, they face numerous challenges including genetic mutations, damaging free radicals and those that are encountered during pathogen infection that may impact viability. The implications of dysfunctional mitochondria highlight the importance of pathways that repair and recover mitochondrial activity. Damaged mitochondria are recovered in part by the mitochondrial unfolded protein response (UPRmt), a retrograde signaling mechanism that transcriptionally regulates genes to help restore mitochondrial homeostasis via the transcription factor ATFS-1. In addition, the UPRmt plays an appreciated role in regulating innate immunity to support host survival during infection. The goal of this study was to identify UPRmt-regulated genes that might have a role in protecting the host against infections. Interestingly, numerous gene products that are regulated by ATFS-1 share characteristics with antimicrobial peptides (AMP) such as their size, charge, and structure. We are currently screening these potential AMPs for potential antimicrobial activity using complimentary approaches. We first conducted gene knockdown studies using RNAi against the putative AMP genes to determine its effect on host survival during infection with the pathogen Pseudomonas aeruginosa. We also overexpressed the genes in the wild-type background to test whether these potential AMPs could reduce the pathogen load in infected animals by performing colony-forming-unit counts on lysed animals. Candidates will also be screened using the novel surface-display approach of SLAY to determine the antibacterial efficacy of potential AMP candidates. While our screening process is ongoing, our preliminary studies have identified a potential AMP that we have named MURA-1 (Mitochondrial UPR Regulated AMP). Knockdown of MURA-1 renders the worm more sensitive to infection while its overexpression reduces colonization of P. aeruginosa. We are in the process of testing the antimicrobial activity of MURA-1 using SLAY. Concurrently, we are also recombinantly expressing MURA-1 for purification to directly test its antimicrobial efficacy against various bacterial pathogens.
[
FEBS J,
2016]
In this issue, we highlight work from J. Julian Blow and colleagues that shows how unreplicated DNA originating from double fork stalls are transmitted and resolved in daughter cells, a report by Yves Barral and colleagues on a potential role for diffusion barriers in ER compartmentalisation in C. elegans and a paper by Shan and colleagues reporting the first high-resolution crystal structure of M. tuberculosis trehalose-6-phosphate phosphatase.