MSC differentiation on two-photon polymerized, stiffness and BMP2 modified biological copolymers

Development of a system of heparin multilayers on titanium surfaces for dual growth factor release

The aim of the present study was to establish a modular platform of poly-L-lysine-heparin (PLL-Hep) polyelectrolyte multilayer (PEM) coatings on titanium surfaces for dual growth factor delivery of recombinant human bone morphogenic protein 2 (rhBMP2) and recombinant human vascular endothelial growth factor 165 (rhVEGF165) in clinically relevant quantities. Release characteristics for both growth factors differed significantly depending on film architecture. rhBMP2 induced activation of alkaline phosphatase in C2C12 cells and proliferation of human mesenchymal stem cells (hMSCs). rhVEGF mediated induction of von Willebrand factor (vWF) in hMSCs and proliferation of human umbilical vein endothelial cells. Osteogenic and angiogenic effects were modified by variation in cross-linking and architecture of the PEMs. By creating multilayer films with distinct zones, release characteristics and proportion of both growth factor delivery could be tuned and surface-activity modified to enhance angiogenic or osteogenic function in various ways. In summary, the system provides a modular platform for growth factor delivery that allows for individual composition and accentuation of angiogenic and osteogenic surface properties.

Vimentin-Rab7a Pathway Mediates the Migration of MSCs and Lead to Therapeutic Effects on ARDS

Acute respiratory distress syndrome (ARDS) is difficult to treat and has a high mortality rate. Mesenchymal stem cells (MSCs) have an important therapeutic effect in ARDS. While the mechanism of MSC migration to the lungs remains unclear, the role of MSCs is of great clinical significance. To this end, we constructed vimentin knockout mice, extracted bone MSCs from the mice, and used them for the treatment of LPS-induced ARDS. H&E staining and Masson staining of mouse lung tissue allowed us to assess the degree of damage and fibrosis of mouse lung tissue. By measuring serum TNF-α, TGF-β, and INF-γ, we were able to monitor the release of inflammatory factors. Finally, through immunoprecipitation and gene knockout experiments, we identified upstream molecules that regulate vimentin and elucidated the mechanism that mediates MSC migration. As a result, we found that MSCs from wild-type mice can significantly alleviate ARDS and reduce lung inflammation, while vimentin gene knockout reduced the therapeutic effect of MSCs in ARDS. Cytological experiments showed that vimentin gene knockout can significantly inhibit the migration of MSCs and showed that it changes the proliferation and differentiation status of MSCs. Further experiments found that vimentin's regulation of MSC migration is mainly mediated by Rab7a. Rab7a knockout blocked the migration of MSCs and weakened the therapeutic effect of MSCs in ARDS. In conclusion, we have shown that the Vimentin-Rab7a pathway mediates migration of MSCs and leads to therapeutic effects in ARDS.