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Synthesis of lyso(bis)phosphatidic acid in rabbit alveolar macrophages

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:5904146

Reported here are studies on the biosynthetic pathway used by normal and BCG elicited alveolar macrophages for the synthesis of lyso(bis)phosphatidic acid (L(bis)PA). Earlier observations by this laboratory have shown that although L(bis)PA is abundant in these cells, there is little de novo synthesis of this lipid. Diaceyl phosphatidylglycerol (PG) labeled with either (1,2,3-/sup 3/H) glycerol or /sup 32/P demonstrated that PG is used as an exogenous substrate for L(bis)PA formation; both glycerol moieties are incorporated. Other phospholipids do not have this capacity. BCG-elicited macrophages are capable of only one-quarter the synthesis of L(bis)PA seen with normal cells, and also show a decreased amount of cell associated substrate. In addition, (/sup 3/H) 1-0-alkyl PG was used as a substrate to test the importance of the sn-1 acyl linkage in the synthetic pathway. This substrate produced less L(bis)PA while dramatically increasing the amounts of labelled phosphatidylethanolamine and phosphatidylcholine within the cell. The alkyl substrate also showed increased uptake by the cell. They conclude that the hydrolysis of the acyl group at the sn-1 position of PG is essential in the synthetic pathway leading to the production of L(bis)PA. They further suggest that the PG used by these cells as an exogenous substrate in vitro is obtained from the PG-rich surfactant surrounding the alveolar macrophage.

Research Organization:
Bowman Grey School of Medicine, Winston-Salem, NC
OSTI ID:
5904146
Report Number(s):
CONF-870644-
Journal Information:
Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 46:6; ISSN FEPRA
Country of Publication:
United States
Language:
English