PAR2-induced inflammatory responses in human kidney tubular epithelial cells

Abstract

Protease-activated receptor-2 (PAR2) is a G protein-coupled receptor abundantly expressed in the kidney. The aim of this study was to profile inflammatory gene and protein expression induced by PAR2 activation in human kidney tubular epithelial cells (HTEC). A novel PAR2 antagonist, GB88, was used to confirm agonist specificity. Intracellular Ca(2+) (iCa(2+)) mobilization, confocal microscopy, gene expression profiling, qRTPCR, and protein expression were used to characterize PAR2 activation. PAR2 induced a pronounced increase in iCa(2+) concentration that was blocked by the PAR2 antagonist. Treatment with SLIGKV-NH2 at the apical or basolateral cell surface for 5 h induced expression of a range of inflammatory genes by greater than fourfold, including IL-1β, TRAF1, IL-6, and MMP-1, as assessed by cDNA microarray and qRTPCR analysis. Using antibody arrays, GM-CSF, ICAM-1, TNF-α, MMP-1, and MMP-10 were among the induced proteins secreted. Cytokine-specific ELISAs identified three- to sixfold increases in GM-CSF, IL-6, IL-8, and TNF-α, which were blocked by GB88 and protein kinase C inhibitors. Treatment of cells at the basolateral surface induced more potent inflammatory responses, with release of MCP-1 and fibronectin to the apical and basolateral compartments; apical treatment only increased secretion of these factors to the apical compartment. PAR2 activation at the basolateral surface dramatically reduced transepithelial electrical resistance (TEER) whereas apical treatment had no effect. There was very little leakage (<5%) of peptides across the cell monolayer (liquid chromatography-mass spectrometry). In summary, SLIGKV-NH2 induced robust proinflammatory responses in HTEC that were antagonized by GB88. These results suggest that PAR2 antagonists could be useful disease-modifying, anti-inflammatory agents in kidney disease.

Protease‐activated receptor 2 does not contribute to renal inflammation or fibrosis in the obstructed kidney

“…PAR2 is activated through proteolytic cleavage at its amino‐terminus by many trypsin‐like proteases including tissue factor/factor VIIa complexes . Activation of PAR2 expressed by tubular epithelial cells induces cell proliferation and secretion of fibronectin, CCL2 and TGF‐β1 . These PAR2‐mediated responses in tubular epithelial cells operate through activation of extracellular signal‐regulated kinase (ERK) signalling and Ca2+ mobilization .…”

Evaluation on Potential Contributions of Protease Activated Receptors Related Mediators in Allergic Inflammation

“…A finding demonstrates that neutrophil elastase can increase PAR-2 expression and MUC5AC mucin release [101] may also implicate the involvement of PAR-2 in airway inflammation. While treatment with SLIGKV-NH 2 at the apical or basolateral cell surface of epithelial cells induces GM-CSF, ICAM-1, TNF- α , MMP-1, and MMP-10 secretion [102], PAR-2 agonist also provokes the production of thymic stromal lymphopoietin (TSLP) in the skin of mice [103]. Since these mediators and cytokines are important promoters of inflammation, PAR-2 should be a pivotal contributor of inflammation.…”

Pharmacological inhibition of protease‐activated receptor‐2 reduces crescent formation in rat nephrotoxic serum nephritis

“…In addition, activation of PAR‐2 in human macrophages can induce inflammatory responses such as increased tumour necrosis factor (TNF) secretion and up‐regulation of HLA‐DR expression . Furthermore, PAR‐2 is expressed in human kidney tubules and PAR‐2 activation in cultured tubular cells via thrombin or peptide‐based agonists induces cell proliferation and secretion of inflammatory cytokines . Thus, PAR‐2 has a potential pathogenic role in inflammatory kidney disease.…”