IGLR-2, a Leucine-Rich Repeat Domain Containing Protein, Is Required for the Host Defense in Caenorhabditis elegans

Abstract

EnterohemorrhagicEscherichia coli(EHEC), a human pathogen, also infectsCaenorhabditis elegans. We demonstrated previously thatC. elegansactivates the p38 MAPK innate immune pathway to defend against EHEC infection. However, whether aC. eleganspattern recognition receptor (PRR) exists to regulate the immune pathway remains unknown. PRRs identified in other metazoans contain several conserved domains, including the leucine-rich repeat (LRR). By screening a focused RNAi library, we identified the IGLR-2, a transmembrane protein containing the LRR domain, as a potential immune regulator inC. elegans. Our data showed thatiglr-2regulates the host susceptibility to EHEC infection. Moreover,iglr-2is required for pathogen avoidance to EHEC. Theiglr-2overexpressed strain, which was more resistant to EHEC originally, showed hypersusceptibility to EHEC upon knockdown of the p38 MAPK pathway. Together, our data suggested thatiglr-2plays an important role inC. elegansto defend EHEC by regulating pathogen-avoidance behavior and the p38 MAPK pathway.