eLife (Apr 2020)

SKAP2 is required for defense against K. pneumoniae infection and neutrophil respiratory burst

  • Giang T Nguyen,
  • Lamyaa Shaban,
  • Matthias Mack,
  • Kenneth D Swanson,
  • Stephen C Bunnell,
  • David B Sykes,
  • Joan Mecsas

DOI
https://doi.org/10.7554/eLife.56656
Journal volume & issue
Vol. 9

Abstract

Read online

Klebsiella pneumoniae is a respiratory, blood, liver, and bladder pathogen of significant clinical concern. We show that the adaptor protein, SKAP2, is required for protection against K. pneumoniae (ATCC 43816) pulmonary infections. Skap2-/- mice had 100-fold higher bacterial burden when compared to wild-type and burden was controlled by SKAP2 expression in innate immune cells. Skap2-/- neutrophils and monocytes were present in infected lungs, and the neutrophils degranulated normally in response to K. pneumoniae infection in mice; however, K. pneumoniae-stimulated reactive oxygen species (ROS) production in vitro was abolished. K. pneumoniae-induced neutrophil ROS response required the activity of SFKs, Syk, Btk, PLCγ2, and PKC. The loss of SKAP2 significantly hindered the K. pneumoniae-induced phosphorylation of SFKs, Syk, and Pyk2 implicating SKAP2 as proximal to their activation in pathogen-signaling pathways. In conclusion, SKAP2-dependent signaling in neutrophils is essential for K. pneumoniae-activated ROS production and for promoting bacterial clearance during infection.

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