A genome-wide in vitro bacterial-infection screen reveals human variation in the host response associated with inflammatory disease.

Journal Article (Journal Article)

Recent progress in cataloguing common genetic variation has made possible genome-wide studies that are beginning to elucidate the causes and consequences of our genetic differences. Approaches that provide a mechanistic understanding of how genetic variants function to alter disease susceptibility and why they were substrates of natural selection would complement other approaches to human-genome analysis. Here we use a novel cell-based screen of bacterial infection to identify human variation in Salmonella-induced cell death. A loss-of-function allele of CARD8, a reported inhibitor of the proinflammatory protease caspase-1, was associated with increased cell death in vitro (p = 0.013). The validity of this association was demonstrated through overexpression of alternative alleles and RNA interference in cells of varying genotype. Comparison of mammalian CARD8 orthologs and examination of variation among different human populations suggest that the increase in infectious-disease burden associated with larger animal groups (i.e., herds and colonies), and possibly human population expansion, may have naturally selected for loss of CARD8. We also find that the loss-of-function CARD8 allele shows a modest association with an increased risk of systemic inflammatory response syndrome in a small study (p = 0.05). Therefore, a by-product of the selected benefit of loss of CARD8 could be increased inflammatory diseases. These results demonstrate the utility of genome-wide cell-based association screens with microbes in the identification of naturally selected variants that can impact human health.

Full Text

Duke Authors

Cited Authors

  • Ko, DC; Shukla, KP; Fong, C; Wasnick, M; Brittnacher, MJ; Wurfel, MM; Holden, TD; O'Keefe, GE; Van Yserloo, B; Akey, JM; Miller, SI

Published Date

  • August 2009

Published In

Volume / Issue

  • 85 / 2

Start / End Page

  • 214 - 227

PubMed ID

  • 19664744

Pubmed Central ID

  • PMC2725265

Electronic International Standard Serial Number (EISSN)

  • 1537-6605

Digital Object Identifier (DOI)

  • 10.1016/j.ajhg.2009.07.012


  • eng

Conference Location

  • United States