MiR-21促进骨髓间充质干细胞向肾小管靶向迁移在急性肾损伤中的作用及机制研究

骨髓间充质干细胞（BMSCs）在肾脏的归巢率和肾小管定植率低严重限制其对急性肾损伤（AKI）的疗效。我们前期采用肾动脉显微注射法显著提高了BMSCs归巢率，但其定植率仍低。已有研究提示肿瘤细胞miR-21高表达量与其迁移能力呈正相关。我们预实验发现，提高BMSCs的miR-21表达可促使干细胞迁移至肾小管。因此提出假说：上调miR-21表达可能提高干细胞肾内迁移力，促进归巢细胞迁移并定植至肾小管，从而更有效地修复AKI。为此，本项目拟：1）利用慢病毒转染和CRISPR/cas9体系分别建立miR-21过表达和缺失的BMSCs细胞系；2）通过体内外实验验证miR-21对BMSCs肾内迁移能力的影响及对AKI修复作用；3）研究miR-21是否通过PTEN/PI3K/Akt信号通路提高BMSCs的迁移能力。本研究将以“提高干细胞肾内迁移”为切入点，为进一步优化AKI干细胞治疗策略提供新思路。

Therapeutic potential of bone marrow-derived mesenchymal stem cells (BMSCs) in acute kidney injury (AKI) was seriously limited by low rates of cell homing and engraftment after transplantation. In previous work, we significantly increased renal retention of grafted BMSCs through renal arterial administration; however, most of BMSCs homing to the kidney were localized primarily to the renal vessels and failed to migrate and integrate into the host renal tubules. It has been suggested that high level of miR-21 is associated with the enhanced migration, invasion of tumor cells. In pre-experiment, we found that increasing the expression of miR-21 could improve the number of BMSCs localized in the injured renal tubules. Thus, we hypothesized that up-regulation of miR-21 in BMSCs might promote their intra-renal migration into injured renal tubules, which may further enhance their therapeutic effects in AKI. To prove this hypothesis, we will: 1）use lentiviral transfection to overexpress miR-21 in BMSCs and CRISPR/cas9 to knockout miR-21 in BMSCs; 2）further validate the in vitro and in vivo effect of miR-21 on the intra-renal migration and the recovery on the AKI; 3) investigate whether the miR-21 regulates the migration of BMSCs through the PTEN/PI3K/Akt pathway. Therefore, this project may provide further optimized strategy for cell therapy of AKI from the view of improving intra-renal cell migration.