Studies on ether-phospholipids of vascular smooth muscle cells. Identification of a rapid Ca(2+)-dependent hydrolysis of alkyl-phosphatidylethanolamine promoted by endothelin-l

Link to Pubmed [PMID] – 9030203

Biochim. Biophys. Acta 1997 Jan;1355(1):69-80

We have investigated the metabolism of 1-O-[3H]octadecyl-sn-glycero-3-phosphocholine ([3H]lyso PAF) and [3H] myristic acid in secondary cultures of aortic smooth muscle cells (SMC) to characterize the origin of second messengers generated upon stimulation with endothelin-l (ET-l). When cells were labelled with [3H]lyso PAF, we observed a transfer of the label from phosphatidylcholine (PC) to phosphatidylethanolamine (PE) In contrast, incubation with [3H]lyso PAF labelled mainly alkyl-subclasses while [3H]myristate was associated with diacyl-subclasses. Using these specific labelling procedures, we have shown that ET-l induced a strong hydrolysis of PE. This hydrolysis was specific for alkyl-PE with a maximum after 5 s of stimulation. We have also observed an extracellular Ca(2+)-dependent increase in diglyceride (DG), phosphatidic acid (PA) and mainly triglyceride (TG) concomitant to alkyl-PE hydrolysis. Thus, alkyl-DG generated from alkyl-PE appears to be a major product in ET-l stimulation of SMC. These results suggest a new level of complexity in the signal transduction cascade involving a specificity for phospholipid subclasses.