ABSTRACT
Interleukin-1 alpha (IL-1alpha) and beta (IL-1beta) are well known factors that stimulate hematopoiesis, nevertheless there are reports that show that they can also inhibit this activity. While both IL-1alpha and IL-1beta induce the expression of hematopoietic cytokines, such as growth factors and their receptors on myeloid cells, helping thus to regulate hematopoiesis, it is not known if their inhibitory activity is also mediated through the induction of other specific cytokines. In this work we show that recombinant human IL-1beta (rhIL-1beta) inhibits the proliferation of a mouse IL-3-dependent myeloid multipotent cell line (32D cl3), without inducing its differentiation. We show that rhIL-1beta induces in 32D cl3 cells the expression of the tumor necrosis factor alpha (TNF-alpha) gene, a well known growth inhibitor, and that the rhIL-1beta growth inhibition property on 32D cl3 cells is partially due to this secreted TNF-alpha, hinting thus that the inhibition of hematopoiesis by IL-1 is mediated through other induced cytokines.
Subject(s)
Interleukin-1/metabolism , Myeloid Cells/metabolism , Tumor Necrosis Factor-alpha/metabolism , Animals , Antibodies/immunology , Cell Division/physiology , Gene Expression Regulation/physiology , Mice , Myeloid Cells/cytology , RNA, Messenger/metabolism , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/immunologyABSTRACT
BACKGROUND: Evidence that sodium caseinate (CasNa) is capable of inhibiting proliferation of hematopoietic precursor cell line 32D and inducing its differentiation into macrophage cells has recently been published. Taking into consideration that hematopoiesis is regulated by growth factors and that macrophage colony-stimulating factor (M-CSF) is a well-known growth factor that induces differentiation of macrophages, in this work we evaluated whether CasNa is capable of inducing expression and secretion of M-CSF in 32D cells. METHODS: We cultured 32D cells in presence and absence of CasNa and compared their proliferation and viability. RNA was extracted from cell lysates to evaluate expression of the gene for M-CSF and its receptor. Cultured conditioned media was used to evaluate presence of M-CSF. RESULTS: Our results showed that CasNa inhibited proliferation of 32D cells and that conditioned media (CM) of these cultures contained M-CSF-like activity. Presence of M-CSF in CM was detected by inhibiting M-CSF activity with anti-M-CSF and presence of this growth factor was confirmed by ELISA assay. We also provided evidence that CasNa induced expression of mRNA for M-CSF in 32D cells as well as increased expression of mRNA for its receptor. CONCLUSIONS: CasNa inhibits proliferation of 32D cells and induces expression of the gene for M-CSF and that of its receptor. It also induces secretion of the bioactive form of M-CSF.
Subject(s)
Caseins/pharmacology , Macrophage Colony-Stimulating Factor/metabolism , Myeloid Progenitor Cells/metabolism , Animals , Bone Marrow Cells/cytology , Cell Differentiation , Cell Division , Cell Line , Cell Line, Tumor , Chelating Agents/pharmacology , Colony-Forming Units Assay , Culture Media, Conditioned/pharmacology , Enzyme-Linked Immunosorbent Assay , Hematopoietic Stem Cells/cytology , Interleukin-3/metabolism , Mice , RNA/metabolism , RNA, Messenger/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Time Factors , Up-RegulationABSTRACT
Objetivo. Evaluar la participación del caseinato de sodio (CasNa) en la modulación de la hematopoyesis. Material y métodos. Se emplearon células 32D, una línea celular hematopoyética multipotencial, de origen murino y dependiente de interleucina-3. Estas células se cultivaron con 0.5 ng/mL de interleucina-3 y con concentraciones variables de CasNa. En los cultivos se realizaron estudios de proliferación celular (conteo directo e incorporación de timidina 3H) y de diferenciación morfológica (tinción con Giemsa), citoquímica (tinciones específicas para monocito-macrófagos y para granulocitos) y funcional (presencia de receptores Fc y reducción de nitro azul de tetrazolio), además se determinó la viabilidad con azul de tripano y la apoptosis por la reacción Tunel in situ. Resultados. Se demostró que el CasNa produce una reducción en la proliferación, dependiente de la dosis, que ésta no es provocada por una disminución de la viabilidad de las células 32D así como tampoco por un aumento de la muerte celular por apoptosis. Además el CasNa indujo la diferenciación de las células 32D hacia monocito-macrófagos en cultivos de 4 días. Conclusiones. Aparentemente el CasNa ejerce una actividad tipo factor estimulador de colonias de macrófagos. Además, parece ser un potente factor de diferenciación de las células 32D, ya que en sólo 4 días de estímulo genera células de tipo monocito-macrófago, a diferencia de los 7 días requeridos por la combinación de G-CSF y GM-CSF.
