title: TNF-alpha response of human monocyte-derived macrophages to Mycobacterium avium, serovar 4, is of brief duration and protein kinase C dependent.
abstract: Human monocyte-derived macrophages (M phi) from the majority of normal donors respond to inoculation with Mycobacterium avium, serotype 4, (MAI) by elaboration of the inflammatory monokines TNF-alpha, IL-1 beta, and IL-6, which are of central importance for the protection against bacterial and parasitic infections. Peak TNF-alpha mRNA levels were of brief duration, being maximal at 1.5 h, and were only slightly higher than background levels at 4 h. Increases of IL-1 beta and IL-6 mRNA levels, on the other hand, persisted for 48 to 72 h. In contrast to LPS, MAI induced the production of only small amounts of TNF-alpha protein in the first 12 h and of large amounts of IL-1 beta and IL-6 protein between 3 and 72 h. MAI-induced TNF-alpha transcripts, in contrast to LPS induced TNF-alpha transcripts, were highly unstable. Their accumulation was blocked and their t 1/2 significantly decreased by the protein kinase C inhibitor staurosporine. In contrast, LPS-induced increases of TNF-alpha mRNA levels and MAI-induced increases of IL-1 beta and IL-6 mRNA levels were PKC independent. The cAMP- and cGMP-dependent protein kinase inhibitors, KT5720 and KT5823, respectively, and the tyrosine kinase inhibitors herbimycin and erbstatin had no effect on the MAI-dependent mRNA accumulation of TNF-alpha, IL-1 beta, and IL-6. W7, a calmodulin-dependent protein kinase inhibitor, was inhibitory in all cases. Thus, MAI-induced TNF-alpha mRNA accumulation is of short duration and PKC dependent. MAI-induced TNF-alpha protein production is low, possibly resulting in a mitigated antimicrobial effect.
authors.affiliation: Department of Rheumatology and Immunology, Brigham's and Womens Hospital, Boston, MA.
authors.forename: H
authors.initials: H
authors.lastname: Gan
authors.forename: G
authors.initials: G
authors.lastname: Newman
authors.forename: P L
authors.initials: PL
authors.lastname: McCarthy
authors.forename: H G
authors.initials: HG
authors.lastname: Remold
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis / Q000235:genetics; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics; D008264:Macrophages / Q000201:enzymology* / Q000378:metabolism / Q000382:microbiology*; D009000:Monocytes; D015269:Mycobacterium avium Complex / Q000276:immunology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D019311:Staurosporine; D013997:Time Factors; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000470:Alkaloids; D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D011493:Protein Kinase C; D019311:Staurosporine