Disturbances in purinergic [Ca2+]i signaling pathways in a transformed rat thyroid cell line.
It was previously shown that in rat thyroid PC-Cl3 cell line, a purinergic P2Y receptor increases the concentration of free cytosolic Ca(2+) ([Ca(2+)](i)) via phospholipase C activation. We here studied whether in a transformed cell line (PC-E1Araf) derived from parental PC-Cl3 cells, ATP is still able to transduce the [Ca(2+)](i)-based intracellular signal.We demonstrate the expression of mRNA for P2Y2 in both PC-Cl3 and PC-E1Araf cells; mRNAs for P2Y1, P2Y4, P2Y6 and P2Y11 were absent. In both cell lines activation of P2Y2 receptor provokes a transient increase in [Ca(2+)](i) followed by a lower sustained phase persisting for over 5min in PC-Cl3 and only 1.5 min in PC-E1Araf cells. In both cell lines the [Ca(2+)](i) reached a plateau level significantly higher than the basal [Ca(2+)](i) level persisting for over 10 min. Removal of extracellular Ca(2+) reduced the initial transient response to ATP in PC-Cl3, but not in PC-E1Araf cells, and completely abolished the plateau phase in both cell lines. In the presence of extracellular Ca(2+) thapsigargin (TG) caused a rise in [Ca(2+)](i) significantly higher in PC-Cl3 than transformed PC-E1Araf cells, while in Ca(2+)-free medium the effect of TG was similar in both cell lines. The capacitative Ca(2+)-entry in PC-Cl3 resulted significantly higher than in PC-E1Araf cells. Further studies were performed in order to investigate whether the different effects of ATP on [Ca(2+)](i) was due to variation in divalent cation plasma membrane permeability. PC-E1Araf cells showed a much lower permeability to Ca(2+), Ba(2+), Sr(2+), Mn(2+), and Co(2+) that may be responsible for the differences in purinergic Ca(2+) signaling pathway with respect to parental PC-Cl3 cells.
Elia
Maria Giovanna
MG
Laboratorio di Fisiologia, Dipartimento di Scienze e Tecnologie Biologiche e Ambientali, Università di Lecce, 73100 Lecce, Italy.
Muscella
Antonella
A
Greco
Simona
S
Vilella
Sebastiano
S
Storelli
Carlo
C
Marsigliante
Santo
S
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000172:deficiency; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002412:Cations / Q000378:metabolism / Q000494:pharmacology; D002461:Cell Line, Transformed; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D058473:Receptors, Purinergic P2Y2; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D002412:Cations; D004791:Enzyme Inhibitors; C546387:P2ry2 protein, rat; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; D000255:Adenosine Triphosphate; D002118:Calcium