Signaling events during induction of plasminogen activator inhibitor-1 expression by sphingosylphosphorylcholine in cultured human dermal fibroblasts.
Sphingosylphosphorylcholine (SPC) is a bioactive sphingolipid metabolite that can enhance wound healing. In a search for effectors downstream of SPC in the wound-healing process, we found that the expression of the gene for plasminogen activator inhibitor-1 (PAI-1) was significantly affected. ELISA and western blot analyses showed that SPC markedly induced PAI-1 production in human dermal fibroblasts cultured in vitro. Inhibition by pre-treatment with pertussis toxin (PTx), but not by tyrphostin A47 (a receptor tyrosine kinase inhibitor), indicated that PTx-sensitive G proteins were involved in SPC-induced PAI-1 expression. SPC elicited a rapid and transient increase in intracellular calcium levels ([Ca2+]i), measured using laser scanning confocal microscopy, which was partly mediated through PTx-sensitive G proteins. Pre-treatment with thapsigargin, but not with EGTA, abolished SPC-induced PAI-1 expression, indicating the importance of Ca2+ release from internal stores. Phorbol-12-myristate-13-acetate (PMA) induced the expression of PAI-1, and pre-treatment with Ro 31-8220 (a PKC inhibitor) markedly suppressed SPC-induced PAI-1 expression. SPC-induced PAI-1 expression was also significantly suppressed by PD98059 (a specific MAPK kinase 1/2 inhibitor). Consistent with this result, SPC stimulated the phosphorylation of p42/44 extracellular signal-regulated kinase (ERK). Together, these results suggest that SPC induces PAI-1 production through a G protein-coupled calcium increase and downstream kinase signaling events in cultured human dermal fibroblasts.
Kye
Kyung-Chae
KC
Department of Dermatology, School of Medicine, Chungnam National University, Daejeon, Korea.
Chae
Eun-Kyung
EK
Piao
Yong-Jun
YJ
Park
Seonyang
S
Park
Jang-Kyu
JK
Kim
Chang Deok
CD
Lee
Jeung-Hoon
JH
Suhr
Ki-Beom
KB
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D020405:Dermis / Q000166:cytology*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics* / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011817:Rabbits; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D014945:Wound Healing / Q000187:drug effects / Q000502:physiology
D017395:Plasminogen Activator Inhibitor 1; C005356:sphingosine phosphorylcholine; D010767:Phosphorylcholine; D011493:Protein Kinase C; D019204:GTP-Binding Proteins; D013110:Sphingosine; D002118:Calcium