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Screening Assays to Characterize Novel Endothelial Regulators Involved in the Inflammatory Response
12:50

Screening Assays to Characterize Novel Endothelial Regulators Involved in the Inflammatory Response

Published on: September 15, 2017

LPS-induced MCP-1 expression in human microvascular endothelial cells is mediated by the tyrosine kinase, Pyk2 via

Appakkudal R Anand1, Ritu Bradley, Ramesh K Ganju

  • 1Department of Pathology, Ohio State University Medical Center, Columbus, OH 43210, USA.

Molecular Immunology
|October 29, 2008
PubMed

Insights

Bacterial endotoxin (lipopolysaccharide or LPS) triggers inflammation by activating Pyk2 kinase in endothelial cells. This pathway, involving p38 MAPK and NF-kappaB, drives MCP-1 production, crucial in sepsis pathogenesis.

Area of Science:

  • Endothelial cell biology
  • Inflammation and immunology
  • Molecular signaling pathways

Background:

  • Bacterial endotoxin (lipopolysaccharide or LPS) is a potent pro-inflammatory molecule affecting endothelial cells.
  • LPS-induced CC chemokine MCP-1 (CCL2) secretion by endothelial cells significantly contributes to sepsis pathogenesis.
  • The precise mechanisms underlying LPS-induced MCP-1 production in endothelial cells remain incompletely understood.

Purpose of the Study:

  • To investigate the role of the non-receptor tyrosine kinase Pyk2 in LPS-mediated MCP-1 production in human microvascular endothelial cells (HMVEC).

Main Methods:

  • HMVECs were treated with LPS, and Pyk2 activation was assessed.
  • Pharmacological inhibition of Pyk2 using Tyrphostin A9.
  • Genetic inactivation of Pyk2 using a dominant-negative Pyk2 mutant (AAV-Pyk2MT) and Pyk2-specific siRNA.
  • Analysis of downstream signaling molecules including p38 MAP kinase (MAPK) and NF-kappaB.
  • Assessment of MCP-1 expression and functional monocyte trans-endothelial migration.

Main Results:

  • LPS treatment led to significant activation of Pyk2 in HMVECs.
  • Inhibition of Pyk2 activity attenuated LPS-induced Pyk2 tyrosine phosphorylation, p38 MAPK activation, NF-kappaB activation, and MCP-1 expression.
  • Specific inactivation of Pyk2 significantly blocked LPS-induced MCP-1 production.
  • Supernatants from Pyk2-inhibited cells showed reduced monocyte trans-endothelial migration, confirming functional inhibition of MCP-1.

Conclusions:

  • The Pyk2-mediated signaling pathway, involving p38 MAPK and NF-kappaB, plays a critical role in LPS-induced MCP-1 production in human microvascular endothelial cells.
  • Targeting Pyk2 may offer a therapeutic strategy to mitigate LPS-driven inflammation in sepsis.

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