miR-145-5p targets MMP2 to protect brain injury in hypertensive intracerebral hemorrhage via inactivation of the Wnt/β-catenin signaling pathway.

Background: Differences in microRNA (miRNA) expression after hypertensive intracerebral hemorrhage (HICH) have been reported in human and animal models. miRNA-145 plays an important role in vascular endothelial cells. The purpose of this work was to determine the role of miR-145-5p in HICH and the molecular mechanisms by which it acts.

Methods: In this study, we constructed a model of hemoglobin-induced HICH in rats and used thrombin-treated human brain microvascular endothelial cells (hBMECs) to create a HICH cell model. To determine brain damage, we tested the rats' neurological performance and measured the cerebral water level of their brain tissue. Cell counting kit 8 (CCK8) was used to determine the viability of cells. Apoptosis was detected using the terminal TdT-mediated dUTP nick end labeling (TUNEL) assay and flow cytometry (FCM). Starbase and TargetScan were used to predict and confirm target genes. Luciferase reporter gene experiments were used to confirm the predictions. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to identify the associated genes and proteins.

Results: We observed a reduction in miRNA-145-5p expression in both the HICH cell model and the rat model. miRNA-145-5p overexpression increased cell survival and preserved newly created blood vessels and vascular permeability in hBMECs. MiRNA-145-5p has been predicted to target matrix metalloproteinase 2 (MMP2). Additionally, MMP2 was identified as a miR-145-5p target gene and shown to be substantially expressed in the thrombin-treated hBMECs. MMP2 overexpression suppressed miR-145-5p-mediated effects and increased hBMECs' malfunction. In comparison with controls, the HICH + AAV-miR-145-5p group performed better on behavioral tests and had less brain water. Additionally, miR-145-5p injection increased ZO-1 and occludin expressions, as determined by immunohistochemical staining in the HICH rat model.

Conclusions: miRNA-145-5p protects against brain injury following HICH by targeting MMP2, suggesting a possible therapeutic mechanism for HICH.