Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Protease-activated receptors (PARs) are a group of four members of the superfamily of G protein-coupled receptors that transduce cell signaling by proteolytic activity of extracellular serine proteases, such as thrombin. Possible expression and functions of PARs in oligodendrocytes, the myelin forming cells of the CNS, are still unclear. Here, the oligodendrocyte cell line OLN-93 was used to investigate the signaling of PARs. By reverse transcription-polymerase chain reaction (RT-PCR), immunostaining and Ca(2+) imaging studies, we demonstrate that OLN-93 cells functionally express PAR-1. PAR-3 seems to be expressed without apparent activity, and PAR-2 and PAR-4 cannot be detected. Short-term stimulation of the OLN-93 cells with PAR-1 agonists, such as thrombin, trypsin and PAR-1 activating peptide, dose-dependently induced a transient rise of [Ca(2+)](i). Concentration-effect curves display a sigmoidal concentration dependence. Elevation of [Ca(2+)](i) induced by PAR-1 mainly resulted from Ca(2+) release from intracellular stores. Studies on the effects of pertussis toxin (PTX), phospholipase C antagonist and 2-APB, showed that in OLN-93 cells (i). the calcium signaling cascade from PAR-1 was mediated through PTX-insensitive G proteins, (ii). activation of phospholipase C and liberation of InsP(3) were events upstream of the Ca(2+) release from the stores. In addition, the present study analyzed PAR-1 desensitization caused by exposure to thrombin, trypsin, and PAR-1 activating peptide, elucidated the influence of the protease cathepsin G on PAR-1 activation, and also characterized PAR-1 desensitization. This is the first study, which shows that OLN-93 oligodendrocytes functionally express PAR-1, and identifies the receptor coupling to mobilization of intracellular calcium. Moreover, the expression of PAR-1 was demonstrated by RT-PCR in primary oligodendrocytes from rat brain.
 ...
PMID:Expression of protease-activated receptors (PARs) in OLN-93 oligodendroglial cells and mechanism of PAR-1-induced calcium signaling. 1514 74

We examined the mechanism of thrombin on proliferation of synovial fibroblasts obtained from rheumatoid arthritis (RA). Thrombin concentration-dependently induced proliferation of synovial fibroblasts. Proliferation in response to thrombin (10 U/ml) was completely blocked by hirudin. TP367 and TP508, peptides corresponding to 2 noncatalytic regions of thrombin, failed to induce cell proliferation. Thrombin did not induce the production of basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), and epidermal growth factor (EGF) in synovial fibroblasts. Expression of proteinase-activated receptor (PAR)-1 and PAR-3 mRNAs was observed in synovial fibroblasts. Thrombin and PAR-1 agonist peptide (AP), but not PAR-3 AP, induced intracellular calcium mobilization. PAR-1 AP induced cell proliferation whereas PAR-3 AP and PAR-4 AP had no effect on proliferation. Pertussis toxin (PTX), a Gialpha protein inhibitor; wortmannin, a PI (phosphatidylinositol) 3-kinase inhibitor; and PD98059, a specific MEK [mitogen-activated protein (MAK) kinase kinase] inhibitor, inhibited the thrombin-induced cell proliferation. Furthermore, the proliferation of synovial fibroblasts was suppressed by U-73122, a PLC (phospholipase C) inhibitor; 2-APB, an antagonist of InsP3 (inositol 1,4,5-triphosphate) receptor; and GF-109203X, a PKC (protein kinase C) inhibitor. These results suggest that thrombin induces the proliferation of RA synovial fibroblasts through the activation of PAR-1, leading to the PTX-sensitive G proteins - PI3 kinase pathway and PTX-insensitive G proteins - PLC (InsP3 receptor) Ca(2+)-PKC branch.
 ...
PMID:Thrombin-stimulated proliferation of cultured human synovial fibroblasts through proteolytic activation of proteinase-activated receptor-1. 1878 3