AUTHOR=Kuo Cheng-Ju , Hsu Ya-Chu , Wang Sin-Tian , Liou Bang-Yu , Lim Serene Boon-Yuean , Chen Yi-Wei , Chen Chang-Shi 

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

JOURNAL=Frontiers in Immunology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2020.561337

DOI=10.3389/fimmu.2020.561337

ISSN=1664-3224

ABSTRACT=<p>Enterohemorrhagic <italic>Escherichia coli</italic> (EHEC), a human pathogen, also infects <italic>Caenorhabditis elegans</italic>. We demonstrated previously that <italic>C. elegans</italic> activates the p38 MAPK innate immune pathway to defend against EHEC infection. However, whether a <italic>C. elegans</italic> pattern 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 in <italic>C. elegans</italic>. Our data showed that <italic>iglr-2</italic> regulates the host susceptibility to EHEC infection. Moreover, <italic>iglr-2</italic> is required for pathogen avoidance to EHEC. The <italic>iglr-2</italic> overexpressed strain, which was more resistant to EHEC originally, showed hypersusceptibility to EHEC upon knockdown of the p38 MAPK pathway. Together, our data suggested that <italic>iglr-2</italic> plays an important role in <italic>C. elegans</italic> to defend EHEC by regulating pathogen-avoidance behavior and the p38 MAPK pathway.</p>