hCTLA4-Gene-Modified Human Bone Marrow-Derived Mesenchymal Stem Cells (hBMMSCs) Maintain POSTN Secretion to Enhance the Migration Capability of Allogeneic hBMMSCs through the Integrin αvβ3/FAK/ERK Signaling Pathway

IL-1β promotes A7r5 and HASMC migration and invasion via the p38-MAPK/Angpt-2 pathway

The migration, proliferation, and inflammatory factor secretion of vascular smooth muscle cells (VSMCs) are involved in the important pathological processes of several vascular occlusive diseases, including coronary atherosclerosis (CAS). Interleukin 1β(IL-1β), as a bioactive mediator of VSMC synthesis and secretion, can promote the pathological progress of CAS. In this study, we further explored the underlying molecular mechanisms by which IL-1β regulates VSMC migration, invasion. We pretreated A7r5 and HASMC with IL-1β for 24 h, and measured the expression of IL-1β, proliferating cell nuclear antigen (PCNA), cyclin D1, matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 2 (MMP9) in the cells by Western blotting. Cell migration and invasion ability were measured by Transwell and wound healing assays. Cell viability was measured by an MTT assay. We found that IL-1β upregulated the expression of proliferation-related proteins (PCNA and Cyclin D1) in A7r5 and HASMC, and induces the secretion of MMP2 and MMP9, promotes cell invasion and migration. In addition, in A7r5 and HASMCs treated with IL-1β, the expression of Angiopoietin-2 (Angpt-2) increased in a time-dependent manner, transfection with si-Angpt-2 suppressed cell migration and invasion, with downregulated MMP2 and MMP9 expression. Parallelly, we further found that the p38-MAPK pathway is activated in cells induced by IL-1β, p38-MAPK inhibitors can down-regulate the expression of Angpt-2. Collectively, these data demonstrated that IL-1β promotes A7r5 and HASMC migration and invasion via the p38-MAPK/Angpt-2 pathway.

Tumor- and Osteoblast-Derived Periostin in Prostate Cancer bone Metastases

Exploring the biological function of periostin (POSTN) in prostate cancer (PCa) bone metastasis is of importance. It was observed that the expression of POSTN was high in PCa, especially highest in PCa metastasized to bone. In this study, we found that inhibiting POSTN in PCa cells could significantly alleviate PCa bone metastasis in vivo, suggesting POSTN is a promising therapeutic target. Since, due to the secreted expression of POSTN in osteoblasts and PCa, we hypothesized the positive feedback loop between osteoblasts and PCa mediated by POSTN in PCa bone metastasis. The in vitro experiments demonstrated that osteoblast-derived POSTN promoted PCa cell proliferation and invasion and PCa cell-derived POSTN promotes proliferation of osteoblasts. Furthermore, we found that POSTN regulated PCa and osteoblast function through integrin receptors. Finally, ¹⁸F-Alfatide II was used as the molecule probe of integrin αvβ3 in PET-CT, revealing high intake in metastatic lesions. Our findings together indicate that targeting POSTN in PCa cells as well as in the osteoblastic may be an effective treatment for PCa bone metastasis.

Demineralized bone matrix combined with cytotoxic T-lymphocyte-associated protein 4 promotes osteogenic differentiation of human bone marrow mesenchymal stem cells and suppresses the activation of T lymphocytes in vitro

Cytotoxic T-lymphocyte-associated protein 4 (CTLA4) can promote osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMMSCs), and CTLA4-modified bone marrow mesenchymal stem cells possess immunoregulatory effects. In the present study, we aimed to construct a new tissue engineering bone using demineralized bone matrix and CTLA4 protein, designated as DBM-CTLA4 (+). The effects of DBM-CTLA4 (+) on the osteogenic differentiation of hBMMSCs and T lymphocyte activation were evaluated through in vitro experiments. The cumulative release of CTLA4 from DBM-CTLA4 (+) was determined using enzyme-linked immunosorbent assay. DBM-CTLA4 (+) was co-cultured in a Transwell chamber with either phytohemagglutinin-treated hBMMSCs or human peripheral blood mononuclear cells (hPBMCs). Osteogenic differentiation of hBMMSCs was assessed by calcium deposition, ALP activity, and the protein levels of COL1A1, RUNX2, BMP2, and OPN. T lymphocyte activity was assessed by measuring the protein levels of IL-2, L-17, HLA-DRA1, IFN-γ, and RANKL. Our results showed that the cumulative release rates of CTLA4 at 7, 14, 21, and 28 days were 12.6% ± 1.4%, 30.2% ± 2.3%, 49.8% ± 3.8%, and 60.5% ± 2.7%, respectively. Compared to the negative control, DBM-CTLA4 (+) promoted the proliferation of hBMMSCs, and enhanced calcium deposition, ALP activity, and protein levels of COL1A1, RUNX2, BMP2, and OPN. Moreover, DBM-CTLA4 (+) decreased the levels of IL-2, IL-17, HLA-DR, IFN-γ, and RANKL in hPBMCs treated with phytohemagglutinin. In conclusion, DBM-CTLA4 (+) promoted proliferation and osteogenic differentiation of hBMMSCs and suppressed T lymphocyte activation.

Phosphorylation inhibition of protein-tyrosine phosphatase 1B tyrosine-152 induces bone regeneration coupled with angiogenesis for bone tissue engineering

A close relationship has been reported to exist between cadherin-mediated cell–cell adhesion and integrin-mediated cell mobility, and protein tyrosine phosphatase 1B (PTP1B) may be involved in maintaining this homeostasis. The stable residence of mesenchymal stem cells (MSCs) and endothelial cells (ECs) in their niches is closely related to the regulation of PTP1B. However, the exact role of the departure of MSCs and ECs from their niches during bone regeneration is largely unknown. Here, we show that the phosphorylation state of PTP1B tyrosine-152 (Y152) plays a central role in initiating the departure of these cells from their niches and their subsequent recruitment to bone defects. Based on our previous design of a PTP1B Y152 region-mimicking peptide (152RM) that significantly inhibits the phosphorylation of PTP1B Y152, further investigations revealed that 152RM enhanced cell migration partly via integrin αvβ3 and promoted MSCs osteogenic differentiation partly by inhibiting ATF3. Moreover, 152RM induced type H vessels formation by activating Notch signaling. Demineralized bone matrix (DBM) scaffolds were fabricated with mesoporous silica nanoparticles (MSNs), and 152RM was then loaded onto them by electrostatic adsorption. The DBM-MSN/152RM scaffolds were demonstrated to induce bone formation and type H vessels expansion in vivo. In conclusion, our data reveal that 152RM contributes to bone formation by coupling osteogenesis with angiogenesis, which may offer a potential therapeutic strategy for bone defects.

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PTP1B plays a dual regulatory role in cadherin- and integrin-related pathways.

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Inhibition of PTP1B Y152 phosphorylation enhances the departure of MSCs from the stem cell niche.

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DBM-MSN/152RM scaffolds coordinate the recruitment of MSCs and ECs.

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DBM-MSN/152RM scaffolds promote bone regeneration and angiogenesis in bone defects.