Arginases and cyclooxygenases are involved in the muscarinic modulation of macrophage induced angiogenesis

DAVEL L., DE LA TORRE E., JASNIS M.A., GOTOH T., DE LUSTIG E.S., SALES M.E.

Instituto Pasteur. Paris, Francia.

Congreso; Euroconference Angiogenesis 2; 2003

We have previously reported that peritoneal macrophages (Mps) from LMM3 tumor cells bearing mice (TMps) potentate angiogenic response induced by inoculating i.d. LMM3 cells. Using an in vivo bioassay, developed in our laboratory, we here investigate the ability of TMps to induce angiogenesis per se and the participation of muscarínico acetylcholine receptors (mAchR) in the neovascularization process. We observed that TMps (3.105 cells/site) produced a positive angiogenic reaction (d=nº of vessels/mm2 skin) in comparison with Mps from normal animals (NMps) (TMps: 2.34±0.6, n=5; NMps: 1.79±0.14, n=7). The latter were unable to induce neovascularization and values of d are comparable to normal skin (1.69±0.20, n=5). The addition of the muscarinic agonist carbachol (CARB) (10-7 M) potently stimulated neovascularization elicited by TMps (TMps+CARB= 4.96±0.41, n=5) and the effect was blunted by atropine (AT) (10-6 M). we also observed that the preincubation of TMps with Nw hydroxy L-arginine (10-4 M) to inhibit arginase activity, indomethacin (10-6 M) or NS-398 (10-5 M), both cyclooxygenase (COX) inhibitors, blocked CARB-stimulated angiogenesis. We confirmed that the addition of CARB ti TMps significantly increased ures production (moles of ures/h/106 cells) in comparison with basal (TMps+CARB: 76,65±5.6; n=4; TMps: 22.2±3.2; n=4) and also stimulated prostaglandin E2 (PGE2) liberation (pg/106 cell) ((TMps+CARB: 2827.6±121.16; n=3; TMps: 28.3±3.1; n=3). Both effects were blunted by AT. We can conclude that in the presence of a growing tumor, the activation of mAchR potently increased Mps induced angiogenic response by activating both arginine metabolism by arginases and PGE2 production “via” COX.