Adenosine-5'-triphosphate up-regulates proliferation of human cardiac fibroblasts.
OBJECTIVE
ATP is a potent signalling molecule that regulates biological activities including increasing or decreasing proliferation in different types of cells. The aim of the present study was to investigate how ATP regulates the proliferation of human cardiac fibroblasts.


METHODS
Reverse transcription (RT)-PCR, Western blot analysis, cell proliferation and migration assays were employed to investigate the effects of ATP on human adult ventricular fibroblasts.


RESULTS
ATP increased cell proliferation in a concentration-dependent manner. Similarly, the P2X receptor agonist α,β-methylene ATP and P2Y receptor agonist ATP-γS also up-regulated cell proliferation. The P2 receptor antagonists suramin and reactive blue-2 prevented the ATP-induced increase in proliferation and RT-PCR and Western blot analysis revealed that mRNAs of P2X(4/7)  and P2Y(2)  are abundant in cardiac fibroblasts. ATP increased phosphorylated PKB (Akt) and ERK1/2 levels; an effect antagonized by suramin, reactive blue-2, the PI3-kinase inhibitor, wortmannin, PKB inhibitor, API-2, and MAPK inhibitor, PD98059. These kinase inhibitors also prevented the ATP-induced increase in proliferation. In addition, ATP enhanced the progression of cells from the G0/G1 phase to the S phase by increasing the expression of proteins for cyclin D1 and cyclin E. Silencing the P2X(4/7)  and P2Y(2)  receptors with siRNA targeting the corresponding receptor diminished ATP-stimulated proliferation and migration of the cardiac fibroblasts.


CONCLUSIONS
ATP activates P2X(4/7)  and P2Y(2)  receptors and up-regulates the proliferation of human cardiac fibroblasts by promoting cell cycling progression. It also increases the migration of these cells. These effects of ATP may be involved in cardiac remodelling of injured hearts.
Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China.
Jing-Bo
JB
Chen
Wen-Juan
WJ
Liu
Hui
H
Che
Jie
J
Liu
Hai-Ying
HY
Sun
Gui-Rong
GR
Li
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D015153:Blotting, Western; D018929:Cell Culture Techniques; D002453:Cell Cycle / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects*; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D006321:Heart / Q000187:drug effects*; D006801:Humans; D009206:Myocardium / Q000166:cytology; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D058469:Receptors, Purinergic P2X / Q000235:genetics; D058470:Receptors, Purinergic P2Y / Q000235:genetics
D034741:RNA, Small Interfering; D058469:Receptors, Purinergic P2X; D058470:Receptors, Purinergic P2Y; D000255:Adenosine Triphosphate