RESUMO
Protein malnutrition causes anemia and leukopenia as it reduces hematopoietic precursors and impairs the production of mediators that regulate hematopoiesis. Hematopoiesis occurs in distinct bone marrow niches that modulate the processes of differentiation, proliferation and self-renewal of hematopoietic stem cells (HSCs). Mesenchymal stem cells (MSCs) contribute to the biochemical composition of bone marrow niches by the secretion of several growth factors and cytokines, and they play an important role in the regulation of HSCs and hematopoietic progenitors. In this study, we investigated the effect of protein malnutrition on the hematopoietic regulatory function of MSCs. C57BL/6NTaq mice were divided into control and protein malnutrition groups, which received, respectively, a normal protein diet (12% casein) and a low protein diet (2% casein). The results showed that protein malnutrition altered the synthesis of SCF, TFG-ß, Angpt-1, CXCL-12, and G-CSF by MSCs. Additionally, MSCs from the protein malnutrition group were not able to maintain the lymphoid, granulocytic and megakaryocytic-erythroid differentiation capacity compared to the MSCs of the control group. In this way, the comprehension of the role of MSCs on the regulation of the hematopoietic cells, in protein malnutrition states, is for the first time showed. Therefore, we infer that hematopoietic alterations caused by protein malnutrition are due to multifactorial alterations and, at least in part, the MSCs' contribution to hematological impairment.
Assuntos
Células da Medula Óssea/efeitos dos fármacos , Proteínas Alimentares/administração & dosagem , Hematopoese/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Deficiência de Proteína/metabolismo , Animais , Células da Medula Óssea/fisiologia , Técnicas de Cocultura , Meios de Cultivo Condicionados , Hematopoese/fisiologia , Leucócitos Mononucleares/fisiologia , Camundongos , Proteínas Proto-Oncogênicas c-kit/metabolismo , RNA/efeitos dos fármacos , RNA/genética , RNA/metabolismoRESUMO
Erythropoiesis is a complex process that starts in the course of embryo formation and it is maintained throughout the life of an organism. During the fetal development, erythropoiesis arises from different body sites and erythroblast maturation occurs in the fetal liver. After birth, erythropoiesis and erythroblast maturation take place exclusively in the bone marrow, generating a lifetime reservoir of red blood cells (RBCs), which are responsible for transporting oxygen through the bloodstream to tissues and organs. Several transcription factors and cytokines, such as GATA-1, GATA-2, FOG-1 and erythropoietin (EPO), constitute an elaborated molecular network that regulates erythropoiesis as they are involved in the differentiation and maturation of RBCs. The profound understanding of erythropoiesis is fundamental to avoid, treat or even soften the effects of erythropoietic clinical disorders and may be useful to improve patients' well-being.