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A7138 - Exogenous Shh Protein Protects Bone Marrow-Derived Endothelial Progenitor Cells from Decreased Proliferation Induced by Cigarette Smoke Extract
Author Block: Y. Zhao, A. Zhou, P. Chen; Department of Respiratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan Province, China.
Rationale: There is increasing evidence that the Sonic hedgehog (Shh)signaling pathway might abnormal express in COPD, but more research is necessary to reveal the relationship directly between Shh signaling pathway and the disease. We have previously identified that bone marrow-derived endothelial progenitor cells (EPCs) palyed a critical role on the repair of pulmonary endothelial cells apoptosis due to cigarette smoke. Here we demonstrate that exogenous Shh protein could protect bone marrow-derived EPCs from decreased proliferation induced by cigarette smoke extract. Method: We firstly investigated the expression of Shh, Ptch1 and Gli1 protein in bone marrow cells of emphysema mice induced by cigarette smoke extract (CSE ) intraperitoneal injection. In vitro study, EPCs were isolated from bone marrow of healthy mice and stimulated with CSE of different final concentrations (0, 0.5%, 1%, 2%) for different hours (6h, 12h, 24h). EPCs were also treated by exogenous shh peptide (rShh group) or combined 1%CSE (CSE + rShh group), then the cell proliferation and the expression of Shh, Ptch1 and Gli1 protein were detected. Results: Compared with control group, the mice with CSE intraperitoneal injection had a significant higher airway resistance and lower dynamic lung compliance. The histopathology also showed the mean lining interval (MLI) and alveolar destruction index (DI) were higher in CSE group. It was indicated that we established the emphysema model successfully. The expression of Shh, Ptch1 and Gli1 protein in bone marrow cells was significantly decreased in emphysema mice. In vitro study, the results showed that 0.5%CSE and 2%CSE decreased the cell proliferation at the early stage (6h), while the 1%CSE promote the bone marrow-drived EPCs proliferation. With the time extended to 12h and 24h, all of the three group has a reduction of proliferation. It was also found that the bone marrow-drived EPCs proliferation ability was significantly increased in rShh group and CSE + rShh group than in CSE group. Meanwhile, the expression of Shh, Ptch1 and Gli1 protein in the CSE group was significantly reduced, while the exogenous Shh protein can promote the expression of Shh, Ptch1 and Gli1 protein and partially rescue the decreased expression of these three protein by CSE treatment. Conclusion: The study suggest that Shh signaling pathway was inhibited in bone marrow cells of emphysema mice and exogenous Shh protein could protect the decreased proliferation of EPCs induced by CSE and partially rescue the lessen of Shh signaling pathway.