Bone marrow stromal cells attenuate oxygen and glucose deprivation followed by re­oxygenation­induced brain microvascular endothelial cell injury.

Ischemic stroke is a severe threat to the health of older individuals. Bone marrow mesenchymal stem cells (BMSCs) have been implicated in ischemic stroke. Urokinase­type plasminogen activator (uPA) and its specific receptor (uPAR) are associated with the pathological process of ischemic stroke. However, the relationship between BMSCs and uPA/uPAR in ischemic stroke remains unclear. For simulating the occurrence of an ischemic stroke in vitro, human cerebral microvascular endothelial cells (HBMECs) were subjected to oxygen and glucose deprivation followed by re­oxygenation (OGD/R) and were then cocultured with BMSCs. 3,4,5­dimethylthiazol­2,5­diphenyltetrazolium bromide and bromodeoxyuridine staining were used for measuring cell viability and proliferation. Flow cytometry was performed for assessing cell apoptosis. Endothelial cell tube formation was determined using angiogenesis assays. Alterations in the protein and gene expression in HBMECs were evaluated using western blot analysis and quantitative reverse transcription­polymerase chain reaction, respectively. OGD/R considerably inhibited the viability and proliferation of HBMECs by inducing apoptosis, which was reversed by BMSCs. Consistently, OGD/R­induced inhibition of angiogenesis was attenuated by BMSCs. In addition, BMSCs could protect HBMECs against OGD/R­induced injury by positively regulating the uPA/uPAR/stromal cell­derived factor­1α (SDF­1α)/C­X­C chemokine receptor type 4 (CXCR4) pathway, and uPA/uPAR could mediate the SDF­1α/CXCR4 pathway in OGD/R­treated HBMECs. Therefore, this study provides novel strategies to investigate the specific role of BMSCs in ameliorating OGD/R­induced vascular endothelial cell injury.

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.