RESUMO
BACKGROUND: Mesenchymal Stem Cells (MSC) are important candidates for therapeutic applications due to their ex vivo proliferation and differentiation capacity. MSC differentiation is controlled by both intrinsic and extrinsic factors and actin cytoskeleton plays a major role in the event. In the current study, we tried to understand the initial molecular mechanisms and pathways that regulate the differentiation of MSC into osteocytes or adipocytes. RESULTS: We observed that actin modification was important during differentiation and differentially regulated during adipogenesis and osteogenesis. Initial disruption of actin polymerization reduced further differentiation of MSC into osteocytes and osteogenic differentiation was accompanied by increase in ERK1/2 and p38 MAPK phosphorylation. However, only p38 MAPK phosphorylation was down regulated upon inhibition of actin polymerization which as accompanied by decreased CD49E expression. CONCLUSION: Taken together, our results show that actin modification is a pre-requisite for MSC differentiation into osteocytes and adipocytes and osteogenic differentiation is regulated through p38 MAPK phosphorylation. Thus by modifying their cytoskeleton the differentiation potential of MSC could be controlled which might have important implications for tissue repair and regeneration.
Assuntos
Citoesqueleto de Actina/química , Diferenciação Celular , Sistema de Sinalização das MAP Quinases , Células-Tronco Mesenquimais/citologia , Actinas/química , Adipócitos/citologia , Adipócitos/metabolismo , Adipogenia , Citocalasina D/farmacologia , Regulação para Baixo , Humanos , Células-Tronco Mesenquimais/metabolismo , Osteócitos/citologia , Osteócitos/metabolismo , Osteogênese , PolimerizaçãoRESUMO
Congenital leukemia is a rare but a well-documented disease in which leukemic process is detected at birth or very shortly thereafter (Philip McCoy and Roy Overton, Commun Clin Cytom 22:85-88, 1995). These leukemias represent approximately 0.8 % of all childhood leukemias. We present a case of congenital acute myeloid leukemia manifesting from the very first day of birth. Diagnosis of acute myeloid leukemia was suspected by the presence of blasts in the peripheral blood smear and was confirmed on bone marrow by flowcytometry. Karyotyping revealed Trisomy 21.