title: Regulation of aminopeptidase N (EC 3.4.11.2; APN; CD13) on the HL-60 cell line by TGF-beta(1).
abstract: Membrane-bound peptidases interfere with cellular growth, differentiation, activation and death by fine-tuning local concentrations of various signaling peptides such as the growth factors, hormones, chemokines and cytokines. We examined the effects of anti-inflammatory cytokine transforming growth factor-beta(1) (TGF-beta(1)) on the expression and activity of aminopeptidase N (APN), an ectoenzyme processing several signaling peptides. Myelo-monocytic HL-60 cell line having high basal APN activity corresponding to the membrane CD13 marker served as a model. Regulation of CD13/APN was assayed at the levels of mRNA and at the membrane marker CD13. Functional properties of CD13/APN were examined by measuring the enzyme activity, and the signal transduction ability, followed as Ca(++) mobilization triggered by APN-blocking WM-15 antibody. TGF-beta(1) at physiological concentrations (0.16 to 2.5 ng/mL) increased expression of CD13 both at mRNA and membrane protein level in a time- and concentration-dependent manner. Transcriptional activation of CD13 by TGF-beta(1) is suggested as actinomycin-D, an inhibitor of RNA synthesis, abrogated the TGF-beta(1)-induced up-regulation of CD13. Increased membrane CD13 expression was associated with an increase of its enzyme (APN) activity and with a decrease of its signal transduction ability. Anti-inflammatory cytokine TGF-beta(1) counteracted the effects of pro-inflammatory cytokine IFN-gamma on membrane CD13 expression in a time- and concentration-dependent fashion, suggesting a cytokine-regulated role of CD13/APN in inflammation. This is the first report on regulation of CD13/APN expression by TGF-beta(1) on immature cells of myelo-monocytic origin. As obtained with physiological concentrations of TGF-beta(1) these findings may be relevant for cytokine-regulated CD13/APN expression on mature myeloid cells in the course of inflammation.
authors.affiliation: Ruder Bosković Institute, Division of Molecular Medicine, Laboratory for Experimental Haematology, Immunology and Oncology, Zagreb, Croatia. gabril@irb.hr
authors.forename: Jelka
authors.initials: J
authors.lastname: Gabrilovac
authors.forename: Davorka
authors.initials: D
authors.lastname: Breljak
authors.forename: Barbara
authors.initials: B
authors.lastname: Cupić
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D019138:Antibodies, Blocking / Q000494:pharmacology; D015415:Biomarkers; D018826:CD13 Antigens / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D003609:Dactinomycin / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D005434:Flow Cytometry; D018922:HL-60 Cells; D006801:Humans; D007371:Interferon-gamma / Q000037:antagonists & inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011961:Receptors, Fc / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*
chemical_list: D000903:Antibiotics, Antineoplastic; D019138:Antibodies, Blocking; D015415:Biomarkers; D012333:RNA, Messenger; D011961:Receptors, Fc; D053773:Transforming Growth Factor beta1; D003609:Dactinomycin; D007371:Interferon-gamma; D018826:CD13 Antigens; D002118:Calcium