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OmpA-mediated rickettsial adherence to and invasion of human endothelial cells is dependent upon interaction with

Robert D Hillman1, Yasmine M Baktash, Juan J Martinez

  • 1Department of Microbiology, The University of Chicago, 920 East 58th Street, Cummings Life Sciences Center 707A, Chicago, IL 60637, USA.

Cellular Microbiology
|November 14, 2012
PubMed

Insights

Rickettsia conorii uses its OmpA protein to attach to and invade human cells. This invasion process involves interactions with mammalian proteins like α2β1 integrin, highlighting multiple adhesin-receptor pairs in bacterial entry.

Area of Science:

  • Microbiology
  • Cell Biology
  • Infectious Diseases

Background:

  • Rickettsia conorii causes Mediterranean spotted fever and is an obligate intracellular pathogen.
  • Surface cell antigen (Sca) proteins, OmpB and OmpA, are key in spotted fever group (SFG) rickettsiae.
  • The role of OmpA in R. conorii invasion is not fully understood.

Purpose of the Study:

  • To investigate the role of R. conorii OmpA in bacterial adherence and invasion.
  • To identify mammalian cell receptors involved in OmpA-mediated invasion.
  • To elucidate the mechanisms of R. conorii entry into host cells.

Main Methods:

  • Expressing OmpA in Escherichia coli to test adherence and invasion.
  • Using recombinant soluble OmpA protein to study mammalian cell binding.
  • Employing functional blocking antibodies, siRNA, and cell lines to identify host ligands.

Main Results:

  • OmpA mediates adherence to and invasion of human endothelial cells.
  • A soluble OmpA domain binds mammalian cells and interacts with β1 integrin.
  • α2β1 integrin is a key mammalian ligand for R. conorii invasion.
  • OmpA-mediated attachment depends on a conserved RGD motif.

Conclusions:

  • OmpA is sufficient for mediating R. conorii adherence and invasion.
  • Multiple adhesin-receptor pairs, including OmpA and α2β1 integrin, facilitate efficient bacterial entry.

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