miRNA-146a Expression Positively Regulates Tumor Necrosis Factor-α-Induced Interleukin-8 Production in Mesenchymal Stem Cells and Differentiated Lung Epithelial-Like Cells

Bone marrow-derived mesenchymal stem cells (BM-MSC) can be differentiated into lung epithelial-like cells (MSC-EC) in vitro. The response of BM-MSC and MSC-EC to stimuli may vary because of their character and differentiation. We aimed to investigate the factors that may influence in vitro differentiation of BM-MSC to MSC-EC. We determined the response of BM-MSC, MSC-EC, bronchial epithelial cells, and alveolar epithelial cells to tumor necrosis factor (TNF)-α stimulation. We also investigated the changes in micro(mi)RNA-146a, miRNA-155, and TNF receptor 1 (TNFR1) expression after stimulation. Our results demonstrate that the addition of transforming growth factor-β1 and extracellular matrix collagen are required to facilitate such differentiation. After 3 weeks of culture, the morphological appearance and expression of airway epithelial markers, cytokeratin and Clara cell secretory protein, in MSC-EC were characteristics of lung epithelial cells. In response to TNF-α stimulation, the maximal interleukin ...