Thy-1 knockdown promotes the osteogenic differentiation of GMSCs via the Wnt/β-catenin pathway

MIR155HG suppresses the osteogenic differentiation of bone marrow mesenchymal stem cells through regulating miR-155-5p and DKK1 expression

BACKGROUND

Increasing evidence has demonstrated that non-coding RNAs, including the lncRNA MIR155HG, are involved in the pathogenesis of postmenopausal osteoporosis (PMOP). In the current study, we studied MIR155HG function in regulation of osteogenic differentiation and tried to reveal the underlying mechanisms.

METHODS

Forty blood samples taken from 20 PMOP patients (PMOP group) and 20 postmenopausal individuals without osteoporosis (control group) were used to compare the contents of MIR155HG and miR-155-5p via RT-PCR. Alizarin red S staining and ALP staining were used to evaluate the osteogenic differentiation potential of bone marrow mesenchymal stem cells (BMSCs).

RESULTS

Elevated levels of MIR155HG and miR-155-5p were observed in the blood samples of the PMOP group. Upregulation of MIR155HG resulted in decreased expression of OPN, OSX, ALP, RUNX2 and β-catenin but increased DKK1 expression, together with decreased Alizarin red S + and ALP + staining areas. However, downregulation of DKK1 did not obviously change the above indices induced by MIR155HG upregulation. Further experiments revealed that MIR155HG caused an increase in the expression of miR-155-5p, which also serves as an inhibitor of the osteogenic differentiation of BMSCs through binding to β-catenin. Consistent with DKK1 knockdown, downregulation of miR-155-5p only also did not obviously reverse the repressive effect of MIR155HG on osteoblastic differentiation, but downregulation of DKK1 and miR-155-5p synchronously restored the osteogenic differentiation ability of BMSCs suppressed by MIR155HG overexpression.

CONCLUSION

MIR155HG suppressed the osteoblastic differentiation of BMSCs by regulating miR-155-5p and DKK1 expression. Either inhibition of miR-155-5p and DKK1 or direct suppression of MIR155HG may be effective approaches for treating PMOP.

Janus silk fibroin/polycaprolactone-based scaffold with directionally aligned fibers and porous structure for bone regeneration

To promote bone repair, it is desirable to develop three-dimensional multifunctional fiber scaffolds. The densely stacked and tightly arranged conventional two-dimensional electrospun fibers hinder cell penetration into the scaffold. Most of the existing three-dimensional structural materials are isotropic and monofunctional. In this research, a Janus nanofibrous scaffold based on silk fibroin/polycaprolactone (SF/PCL) was fabricated. SF-encapsulated SeNPs demonstrated stability and resistance to aggregation. The outside layer (SF/PCL/Se) of the Janus nanofiber scaffold displayed a structured arrangement of fibers, facilitating cell growth guidance and impeding cell invasion. The inside layer (SF/PCL/HA) featured a porous structure fostering cell adhesion. The Janus fiber scaffold containing SeNPs notably suppressed S. aureus and E. coli activities, correlating with SeNPs concentration. In vitro, findings indicated considerable enhancement in alkaline phosphatase (ALP) activity of MC3T3-E1 osteoblasts and upregulation of genes linked to osteogenic differentiation with exposure to the SF/PCL/HA/Se Janus nanofibrous scaffold. Moreover, in vivo, experiments demonstrated successful critical bone defect repair in mouse skulls using the SF/PCL/HA/Se Janus nanofiber scaffold. These findings highlight the potential of the SF/PCL-based Janus nanofibrous scaffold, integrating SeNPs and nHA, as a promising biomaterial in bone tissue engineering.