cAMP a second messenger involved in signaling along the phagocytic pathway.

LEIVA N; PAVAROTTI M; COLOMBO MI; DAMIANI MT

Merlo. San Luis. Argentina.

Congreso; XXII Reunión Científica Anual de la Sociedad de Biología de Cuyo.; 2004

Sociedad de Biología de Cuyo

Phagocytosis is a process by which macrophages internalize large extracellular particles. Phagosomes fuse and exchange materials with endosomes, Golgi-derived vesicles and lysosomes. By these events, phagosomes mature and acquire degradative ability. Phagocytosis is a highly regulated process but the signaling involved still remains unclear. The objective of this work was to unravel the participation of cAMP along the phagocytic pathway. We used a butyryl derivate of cAMP that can cross the plasma membrane and  St. aureus opsonized with radiolabelled antibodies as phagocytic particles. Macrophage cell-associated radioactivity was taken as an index of phagocytosis. Our results showed that the increase on cAMP intracellular levels stimulates particle engulfment. Similar results were obtained when we used forskolin, an activator of adenyl cyclase, enzyme that produces cAMP from ATP. The addition of IBMX, an inhibitor of phosphodiesterases, prevents cAMP hydrolysis, and as a consequence augments cAMP effects. Regarding to phagosome maturation, the rise in cAMP intracellular levels reduces particle degradation. These results suggest that cAMP, acting as a second messenger, regulates phagocytosis and trafficking along the phagocytic pathway.