Heat Stress Reduces the Susceptibility of Caenorhabditis elegans to Orsay Virus Infection.

Yuqing Huang,Lisa Van Sluijs,Mark G Sterken,Koen Van Zwet,Gorben P Pijlman,Jan E Kammenga

doi:10.3390/genes12081161

Abstract

The nematode Caenorhabditis elegans has been a versatile model for understanding the molecular responses to abiotic stress and pathogens. In particular, the response to heat stress and virus infection has been studied in detail. The Orsay virus (OrV) is a natural virus of C. elegans and infection leads to intracellular infection and proteostatic stress, which activates the intracellular pathogen response (IPR). IPR related gene expression is regulated by the genes pals-22 and pals-25, which also control thermotolerance and immunity against other natural pathogens. So far, we have a limited understanding of the molecular responses upon the combined exposure to heat stress and virus infection. We test the hypothesis that the response of C. elegans to OrV infection and heat stress are co-regulated and may affect each other. We conducted a combined heat-stress-virus infection assay and found that after applying heat stress, the susceptibility of C. elegans to OrV was decreased. This difference was found across different wild types of C. elegans. Transcriptome analysis revealed a list of potential candidate genes associated with heat stress and OrV infection. Subsequent mutant screens suggest that pals-22 provides a link between viral response and heat stress, leading to enhanced OrV tolerance of C. elegans after heat stress.

Highlights

Our results show that heat stress (HS) reduces the susceptibility of C. elegans to Orsay virus (OrV) infection and suggest that pals-22 plays an important role in this process
Our results point at the fact that HS could enhance the tolerance of C. elegans against OrV infection, depending on the time after infection
C. elegans is exposed to a multitude of biotic and abiotic factors, some of which trigger a specific innate response of C. elegans

Summary

Introduction

Caenorhabditis elegans is a free-living bacterivorous nematode, and natural populations are closely associated with decaying organic matter. This leads to a continuous exposure to many different (a)biotic factors, including pathogens [1]. Pathogens include a range of bacteria, fungi, microsporidia, and viruses [2] Many of these abiotic and biotic challenges disturb proteostasis and trigger intrinsic stress responses. Different pathogens affecting C. elegans have been studied in the laboratory, including microsporidia, bacteria, and a virus [1]. Among these pathogens, the Orsay virus (OrV) is currently the only virus known that naturally infects C. elegans

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