Inhibin-α, a member of the transforming growth factor (TGF-β) superfamily, has been involved in bone turnover during the menopausal transition via endocrine effects, and it was previously reported that inhibins may antagonize the function of BMPs. Certainly, one of the most important functions of BMPs is to induce osteogenic differentiation. BMP9 as one of the most potent BMPs to induce osteogenic differentiation has gotten more and more attentions. Nonetheless, the effects of inhibin-α on osteogenesis remain unknown. Besides, mesenchymal stem cells (MSCs) with the ability to differentiate into multiple mesenchymal lineages, including osteoblasts, adipocyte, chondrocytes, and myoblasts in vitro, have become the promising seed cells for bone tissue engineering. Here, we investigated the role of inhibin-α on BMP9-induced osteogenic differentiation in MSCs and tried to discover the mechanism underlying this process. We found inhibin-α apparently reduced the classical osteogenic markers and the ectopic bone formation induced by BMP9. In addition, the ratio of OPG to RANKL is declined also in the presence of inhibin-α. For mechanism, we found that exogenous expression of inhibin-α inhibits BMP9-induced osteogenic differentiation through blocking BMP/Smad signal transduction and activating NF-κB signal which is repressed by BMP9. Thus, our findings indicated that inhibin-α has a negative effect on BMP9-induced osteogenic differentiation in MSCs, which may provide a novel insight into the regulation of skeletal development and new strategy for bone tissue engineering.
Toll like receptors (TLRs) induced response plays a vital role in B-cell development and activation, in which TLR7-mediated and TLR9-mediated response interact together and play antagonistic or cooperative roles at different situations. Previous studies showed that the transcription factor signal transducer and activator of transcription (STAT) 3 was one of the key transcriptional factors (TFs) needed for both TLR7 and TLR9 signaling in B cell, and patients with autosomal dominant hyper IgE syndromes (AD-HIES) due to STAT3 mutations having defective TLRs response in B cells. However, how STAT3 affects its target genes and the downstream signaling pathways in B cell upon TLRs stimulation remains unclarified on a genome-wide level. ChIP-seq and RNA-seq was used in this study to identify the STAT3 targets in response to TLRs stimulation in human B cell. STAT3 ChIP-seq results showed a total of 611 and 2,289 differential STAT3-binding sites in human B cell after TLR7 and TLR9 agonists stimulation, respectively. RNA-seq results showed 1,186 and 1,775 differentially expressed genes after TLR7 and TLR9 activation, respectively. We identified 47 primary STAT3 target genes after TLR7 activation and 189 target genes after TLR9 activation in B cell by integration of STAT3 ChIP-seq and RNA-seq data. Among these STAT3 primary targets, we identified 7 TFs and 18 TFs for TLR7 and TLR9 response, respectively. Besides, we showed that STAT3 might regulate TLR9, but not TLR7 response in B cells through directly regulating integrin signaling pathway, which might further affect the antagonism between TLR7 and TLR9 signaling in B cell. Our study provides insights into the molecular mechanism of human TLRs response in B cell and how it can be regulated, which helps to better understand and modulate TLR-mediated pathogenic immune responses in B cell.
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