Abstract
Current drug therapy in myelofibrosis with myeloid metaplasia (MMM) still can not get great progress, the development of the myelofibrosis eventually causes bone marrow failure. The histopathology of MMM patients showed that the bone marrow tissue were full of marrow fibroblasts and an extensive deposition of collagens. Further researches suggested that the proliferation of the fibroblasts was controlled by many factors. One of the most important factor was TGF-β1, and its effects largely depended on Smad pathway. In order to understand the effects of TGF-β1 on the proliferation of marrow fibroblasts, we stimulated the normal human bone marrow fibroblasts with different concentrations of TGF-β1 in the current study. The proliferation test with direct cell counting and MTT assay revealed that different concentrations of TGF-β1 had various effects and it could get the maximal proliferation effect at 0.1ng/ml. Then we detected the Smad3 mRNA and Smad7 mRNA in one normal human bone marrow fibroblasts with RT-PCT methods at above concentration (0.1ng/ml). We found that the expression level of Smad3 mRNA decreased with the time, and that the expression level of Smad7 mRNA reached the highest at 30 min after stimulation by TGF-β1, then it began to reduce. These results suggested that TGF-β1 activate the Smads pathway in normal human marrow fibroblasts, and its proliferation effect require the activation of this pathway. We also noticed that the changes of the smad3 mRNA and smad7 mRNA were similar in skin fibroblasts stimulated by TGF-β1. These changes were considered as a feedback modulation mechanism. Whether the over-proliferation of marrow fibroblasts in MMM patients is correlated with the imbalance of this feedback warrants further research. It may provide a more specific and targeted therapy for blocking myelofibrosis.
Fig A The expression of Smad3 mRNA stimulated by TGF-β 1(0.1ng/ml) at different time.
Fig B The expression of Smad7 mRNA stimulated by TGF-β 1(0.1ng/ml) at different time.
Fig A The expression of Smad3 mRNA stimulated by TGF-β 1(0.1ng/ml) at different time.
Fig B The expression of Smad7 mRNA stimulated by TGF-β 1(0.1ng/ml) at different time.
