Protease-activated receptor-1-induced calcium signaling in gingival fibroblasts is mediated by sarcoplasmic reticulum calcium release and extracellular calcium influx.
Thrombin is a serine protease activated during injury and inflammation. Thrombin and other proteases generated by periodontal pathogens affect the behavior of periodontal cells via activation of protease-activated receptors (PARs). We noted that thrombin and PAR-1 agonist peptide stimulated intracellular calcium levels ([Ca2+]i) of gingival fibroblasts (GF). This increase of [Ca2+]i was inhibited by EGTA and verapamil. U73122 and neomycin inhibited thrombin- and PAR-1-induced [Ca2+]i. Furthermore, 2-APB (75-100 microM, inositol triphosphate [IP3] receptor antagonist), thapsigargin (1 microM), SKF-96365 (200 microM) and W7 (50 and 100 microM) also suppressed the PAR-1- and thrombin-induced [Ca2+]i. However, H7 (100, 200 microM) and ryanodine showed little effects. Blocking Ca2+ efflux from mitochondria by CGP37157 (50, 100 microM) inhibited both thrombin- and PAR-1-induced [Ca2+]i. Thrombin induced the IP3 production of GF within 30-seconds of exposure, which was inhibited by U73122. These results indicate that mitochondrial calcium efflux and calcium-calmodulin pathways are related to thrombin and PAR-1 induced [Ca2+]i in GF. Thrombin-induced [Ca2+]i of GF is mainly due to PAR-1 activation, extracellular calcium influx via L-type calcium channel, PLC activation, then IP3 binding to IP3 receptor in sarcoplasmic reticulum, which leads to intracellular calcium release and subsequently alters cell membrane capacitative calcium entry.
Jeng
Jiiang-Huei
JH
Laboratory of Dental Pharmacology and Toxicology, Department of Dentistry, College of Medicine, National Taiwan University Hospital and National Taiwan University, Taipei, Taiwan.
Chan
Chiu-Po
CP
Wu
Hui-Lin
HL
Ho
Yuan-Soon
YS
Lee
Jang-Jaer
JJ
Liao
Chang-Huei
CH
Chang
Yu-Kaung
YK
Chang
Hsiao-Hua
HH
Chen
Yi-Jane
YJ
Perng
Pey-Jey
PJ
Chang
Mei-Chi
MC
D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D020746:Calcium Channels, L-Type / Q000187:drug effects; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000502:physiology*; D005881:Gingiva / Q000502:physiology*; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D009355:Neomycin / Q000494:pharmacology; D044463:Receptor, PAR-1 / Q000378:metabolism*; D012433:Ryanodine / Q000494:pharmacology; D012519:Sarcoplasmic Reticulum; D013449:Sulfonamides / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D013917:Thrombin / Q000378:metabolism; D014700:Verapamil / Q000494:pharmacology
D001896:Boron Compounds; D020746:Calcium Channels, L-Type; D004791:Enzyme Inhibitors; D044463:Receptor, PAR-1; D013449:Sulfonamides; D012433:Ryanodine; C017967:W 7; D019284:Thapsigargin; D014700:Verapamil; C109986:2-aminoethoxydiphenyl borate; D013917:Thrombin; D009355:Neomycin; D002118:Calcium