NGF/TrkA promotes the vitality, migration and adhesion of bone marrow stromal cells in hypoxia by regulating the Nrf2 pathway

Background: Bone marrow stromal cells (BMSCs) transplantation is a treatment strategy for ischemic stroke (IS) with great potential. However, the vitality, migration and adhesion of BMSCs are greatly impaired due to the harsh environment of the ischemic area, which affects the therapeutic effects. Herein, we aimed to investigate the roles of nerve growth factor (NGF) in regulating cell behaviors of BMSCs in IS.

Methods: The mRNA and protein expressions were assessed using qRT-PCR and western blot, respectively. To simulate ischemic-like conditions in vitro, Brain microvascular (bEnd.3) cells were exposed to oxygen and glucose deprivation (OGD). Cell viability and cell proliferation were evaluated by MTT assay and BrdU assay, respectively. Transwell migration and cell adhesion assays were carried out to determine cell migration and adhesion of BMSCs, respectively, coupled with flow cytometry to evaluate cell apoptosis of bEnd.3 cells. Finally, angiogenesis assay was performed to assess the angiogenesis ability of bEnd.3 cells.

Results: NGF overexpression resulted in increased cell vitality, adhesion and migration of BMSCs, while NGF knockdown presented the opposite effects. We subsequently discovered that TrkA was a receptor for NGF, and TrkA knockdown significantly inhibited the cell viability, migration and adhesion of BMSCs. Besides, Nrf2 was confirmed as the downstream target of NGF/TrkA to promote the viability, adhesion and migration of BMSC cells. Finally, NGF-silenced BMSCs could not effectively restore the OGD-induced brain microvascular cell damage.

Conclusions: NGF/TrkA promoted the viability, migration and adhesion of BMSCs in IS via activating Nrf2 pathway.