title: Cytokine expression from bone marrow derived macrophages.
abstract: Monocytes and macrophages show marked phenotypic variation dependent on their tissue of origin. Peripheral blood monocytes have been found to be sources of a variety of cytokines, but isolated marrow macrophages have not been characterized in this regard. Marrow macrophages form a predominant component of murine adherent Dexter stromal cells and can be isolated by sequential explant culture in colony-stimulating factor-1 (CSF-1). We have studied murine (Balb/c) bone marrow macrophage (BMM) cytokine production in the presence or absence of CSF-1, the lectin pokeweed mitogen (PWM) or interleukin-3 (IL-3). Biologic activity in conditioned media (cm) from control and induced BMM was assessed using the factor-dependent cell lines 32D, NFS-60, T1165, MC-6 and FDC-P1. Cell line stimulation and antibody blocking indicated the presence of c-kit ligand, interleukin-6 (IL-6) and granulocyte colony-stimulating factor (G-CSF). This stimulatory activity was increased by exposure to PWM or the combination of CSF-1 and PWM or CSF-1 and IL-3. CSF-1, as determined by radioimmunoassay (RIA), was essentially undetectable in baseline cm and induction was not seen with PWM or CSF-1. Baseline or "constitutive" expression of BMM and mRNA for CSF-1 and c-kit ligand was seen. Uninduced BMM did not express mRNA for G-CSF, granulocyte-macrophage CSF (GM-CSF), IL-6 or IL-3. CSF-1 induced increased expression of IL-6 mRNA, PWM induced increased expression of G-CSF and IL-6 mRNA and the combination of PWM and CSF-1 induced expression of CSF-1, G-CSF and IL-6 mRNA. Varying levels of CSF-1 had differential effects on cytokine production. Increasing levels of CSF-1 increased IL-6 mRNA and downmodulated CSF-1 mRNA expression. There was a biphasic response of c-kit ligand mRNA expression to CSF-1 exposure; low levels of CSF-1 (50 U/mL) induced, while higher levels (2000 U/mL) inhibited, expression. These data indicate that BMM (and by analogy the macrophage component of Dexter culture stroma), are important sources of CSF-1 and c-kit ligand but not GM-CSF or IL-3. BMM can also be induced to express IL-6 and/or G-CSF. Lastly, CSF-1, by differentially modulating BMM cytokine production in a holocrine or autocrine manner, may function as a central regulator of stromal based hematopoiesis.
authors.affiliation: University of Virginia Health Sciences Center, Charlottesville 22908.
authors.forename: D S
authors.initials: DS
authors.lastname: Temeles
authors.forename: H E
authors.initials: HE
authors.lastname: McGrath
authors.forename: E L
authors.initials: EL
authors.lastname: Kittler
authors.forename: R K
authors.initials: RK
authors.lastname: Shadduck
authors.forename: V K
authors.initials: VK
authors.lastname: Kister
authors.forename: R B
authors.initials: RB
authors.lastname: Crittenden
authors.forename: B L
authors.initials: BL
authors.lastname: Turner
authors.forename: P J
authors.initials: PJ
authors.lastname: Quesenberry
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002478:Cells, Cultured; D003115:Colony-Stimulating Factors / Q000494:pharmacology; D017077:Culture Media, Conditioned; D016207:Cytokines / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D016179:Granulocyte Colony-Stimulating Factor / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D007377:Interleukin-3 / Q000494:pharmacology; D015850:Interleukin-6 / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D011863:Radioimmunoassay
chemical_list: D003115:Colony-Stimulating Factors; D017077:Culture Media, Conditioned; D016207:Cytokines; D007377:Interleukin-3; D015850:Interleukin-6; D011043:Pokeweed Mitogens; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D016179:Granulocyte Colony-Stimulating Factor; D019009:Proto-Oncogene Proteins c-kit