Proinflammatory and proliferative responses of human proximal tubule cells to PAR-2 activation.
Despite the abundant expression of protease-activated receptor (PAR)-2 in the kidney, its relevance to renal physiology is not well understood. A role for this receptor in inflammation and cell proliferation has recently been suggested in nonrenal tissues. The aims of this study were to demonstrate that human proximal tubule cells (PTC) express functional PAR-2 and to investigate whether its activation can mediate proinflammatory and proliferative responses in these cells. Primary human PTC were cultured under serum-free conditions with or without the PAR-2-activating peptide SLIGKV-NH2 (up to 800 microM), a control peptide, VKGILS-NH2 (200 microM), or trypsin (0.01-100 nM). PAR-2 expression (RT-PCR), intracellular Ca2+ mobilization (fura-2 fluorimetry), DNA synthesis (thymidine incorporation), fibronectin production (ELISA, Western blotting), and monocyte chemotactic protein (MCP)-1 secretion (ELISA) were measured. Trypsinogen expression in kidney and PTC cultures was determined by immunohistochemistry and Western blotting. In the kidney PTC were the predominant cell type expressing PAR-2. SLIGKV-NH2, but not VKGILS-NH2, stimulated a rapid concentration-dependent mobilization of intracellular Ca2+ and ERK1/2 phosphorylation and, by 24 h, increases in DNA synthesis, fibronectin secretion, and MCP-1 secretion. These delayed responses appeared to be independent of ERK1/2. Trypsin produced similar rapid but not delayed responses. Trypsinogen was weakly expressed by PTC in the kidney and in culture. In summary, PTC are the main site of PAR-2 expression in the human kidney. In PTC cultures SLIGKV-NH2 initiates proinflammatory and proliferative responses. Trypsinogen expressed within the kidney has the potential to contribute to PAR-2 activation in certain circumstances.
Vesey
David A
DA
1Centre for Kidney Disease Research, University of Queensland Department of Medicine, Princess Alexandra Hospital, Brisbane, Qld 4102, Australia. david_vesey@health.qld.gov.au
Kruger
Wade A
WA
Poronnik
Philip
P
Gobé
Glenda C
GC
Johnson
David W
DW
D000368:Aged; D002118:Calcium / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000209:etiology*; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D044464:Receptor, PAR-2 / Q000819:agonists / Q000378:metabolism*; D014357:Trypsin / Q000494:pharmacology; D014362:Trypsinogen / Q000378:metabolism
C111835:CCL2 protein, human; D018932:Chemokine CCL2; D005353:Fibronectins; D009842:Oligopeptides; D044464:Receptor, PAR-2; C515807:seryl-leucyl-isoleucyl-glycyl-lysyl-valinamide; D014362:Trypsinogen; D004247:DNA; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D014357:Trypsin; D002118:Calcium