Synergistic and selective stimulation of gelatinase B production in macrophages by lipopolysaccharide, frvms-retinoic acid and CGP 41251, a protein kinase C regulator

摘要

The production of gelatinase B by macrophages is relevant in the immunologieal and migratory functions of macrophages. CGP 41251, an inhibitor (if protein kinase C (PKC), was found to stimulate the expression of gelatinase B in macrophages, as shown by the study of two different monoeytie/macrophagie cell lines, mouse RAW 264.7 and human THP-1 cells. When human monocytes and rat peritoneal maerophages were treated with CGP 41251, insignificant increases of 10 and 25% were obtained. This can possibly be due to the presence of contaminating cells in these two enriched populations, since the CGP 41251 treatment of non-macrophagic cell lines inhibited their PMA-indueed gelutinaxc B production. Taken together, these results suggest that the stimulatory effect of CGP 41251 is specific to cells of the monocylic lineage. Using RAW 264.7 cells as a model, the effect of CGP 41251 is additive to that obtained using lipopolysaccharide (LPS) and phorboi 12-myristate 13-acetate (PMA), as revealed by gelatin zymography and Northern blot analysis. The stimulatory effect of CGP 41251 on gelatinase B production in RAW 264.7 was: (a) inhibited by calphostin C (as is the LPS-induced response), indicating a PKC-dependenee; (b) inhibited by dexamethasone (as opposed to the LPS-induced response); and (c) enhanced by addition of /mn.v-rclinoic acid (RA). In fact, RA can induce gelatinase B production, either alone or in synergy with LPS and/or CGP 41251, since the combination of the three agents gives the highest gelatinase B response, at both the protein and the mRNA levels. This represents an important observation considering that RA is now being tested as an anti-cancer agent and proposed for prevention studies.