Bradykinin induces phosphoinositide turnover, 1,2-diglyceride formation, and growth in cultured adult human keratinocytes.
The effects of bradykinin on activation of phosphoinositide turnover, 1,2-diglyceride formation, and growth of cultured adult human keratinocytes were investigated. Keratinocytes specifically bound [3H]bradykinin with high affinity (kd = 3.4 nM) and displayed 1.5 X 10(5) binding sites/cell. Bradykinin caused a rapid dose-dependent increase in inositol trisphosphate (IP3) inositol bisphosphate, and inositol monophosphate. IP3 was maximally increased (fivefold) at 30 s and remained elevated for at least 10 min. Half maximal stimulation of IP3 formation was observed at 27 nM bradykinin. IP3 accumulation was equally elevated by bradykinin and lys-bradykinin but was not stimulated by des-Arg9-bradykinin, indicating that phospholipase C in cultured keratinocytes is coupled to B2 bradykinin receptors. Treatment of keratinocytes with active phorbol ester (TPA) caused a significant inhibition (50%) of bradykinin-induced IP3 accumulation, suggesting negative regulation of phospholipase C by protein kinase C. Bradykinin also caused a significant elevation in 1,2-diacylglycerol (DAG) content. DAG content was maximally elevated (twofold) at 1 min and remained elevated for at least 10 min. Bradykinin also caused a significant (twofold, p less than 0.02) increase in keratinocyte growth. These data demonstrate that bradykinin is a potent agonist of the phospholipase C/protein kinase C signal transduction system in cultured adult human keratinocytes and that activation of this pathway by bradykinin is associated with increased keratinocyte growth.
Talwar
H S
HS
Department of Dermatology, University of Michigan Medical Center, Ann Arbor.
Fisher
G J
GJ
Voorhees
J J
JJ
D000328:Adult; D001920:Bradykinin / Q000494:pharmacology*; D002455:Cell Division; D002478:Cells, Cultured; D004075:Diglycerides / Q000378:metabolism*; D005260:Female; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D008875:Middle Aged; D010716:Phosphatidylinositols / Q000378:metabolism*; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter / Q000032:analysis; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D004075:Diglycerides; D010716:Phosphatidylinositols; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter; D010566:Virulence Factors, Bordetella; D013755:Tetradecanoylphorbol Acetate; D001920:Bradykinin