Increased Expression of TMPRSS11E Is Involved in LPS- or Poly(I:C)-mediated Inflammation.

Transmembrane serine proteases are a group of enzymes that are implicated in diverse biological processes. Transmembrane serine protease 11E () is expressed in epithelial cells. Previous studies on TMPRSS11E mainly focused on its function in tumor progression. In this study, we investigated the association of TMPRSS11E with the inflammatory response. We found that TMPRSS11E levels were upregulated in the BAL fluid of patients with acute respiratory distress syndrome and LPS-stimulated cultured epithelial cells. In an LPS-induced acute lung injury mouse model and a cercal ligation and puncture-induced sepsis model, increased expression levels of TMPRSS11E were also observed in the lung tissues. Knockdown of TMPRSS11E suppressed the proinflammatory cytokine release and alleviated lung injury. In addition, increased TMPRSS11E expression was detected in lung tissues of poly(I:C)-challenged mice, and overexpression of TMPRSS11E aggregated the lung injury. Unexpectedly, ectopic TMPRSS11E expression in macrophages was observed. Protease-activated receptor-1 was proteolytically activated by TMPRSS11E and enhanced the levels of proinflammatory cytokines. Taken together, our results indicate that TMPRSS11E can be induced during inflammatory response triggered by infection. Therefore, interventions with TMPRSS11E can aid in the treatment of pulmonary inflammation.