Knockdown of RUNX2 Attenuated A1 Astrocyte Overactivation, Brain Injury, and Cerebral Edema During Ischemic Stroke

Although researchers began to unravel the potential significance of Runt-related transcription factor 2 (RUNX2) in some of neurological diseases, the role of RUNX2 in ischemic stroke remained unclear. Blood samples and clinical information were collected from stroke patients and control subjects. Besides, middle cerebral artery occlusion (MCAO) mice model and astrocytes oxygen-glucose deprivation/reperfusion (OGD/R) were established to simulate the pathological process of stroke in vivo and in vitro. Loss-of-function assay was used to assess the effect of RUNX2 on astrocytes function. HE staining and Nissl staining were used to examine the histopathological changes of brain tissues in mice. TTC staining was used to measure the cerebral infarct volume in mice. Morri's water maze test, the corner turn test, and the balance beam test were performed to evaluate neurobehavioral performances of mice. The results showed that the expression and serum content of RUNX2 were upregulated in stroke patients and mice. Knocking-down RUNX2 inhibited OGD/R-induced increases of proliferation and migration, while reversed the decrease of apoptosis in astrocytes. Moreover, RUNX2 knockdown also suppressed the inflammatory response in OGD/R-treated astrocytes and promoted the conversion of the reactive astrocyte phenotype from A1 to A2. The serum mRNA expression and level of RUNX2 were both notably increased in patients with cerebral edema. RUNX2 knockdown weakened cerebral edema and swelling of astrocytes. The results of HE staining and Nissl staining suggested that RUNX2 knockdown notably improved neuronal damage in the brain tissues of MCAO mice and also improved the injured performance of MCAO stroke mice in the behavioral test. In conclusion, RUNX2 expression was upregulated during the pathological progression of ischemic stroke. Furthermore, the knockdown of RUNX2 alleviated OGD/R-induced astrocytes activation and swelling, while inhibiting the polarization and inflammatory response in astrocytes. More importantly, RUNX2 interference also improved neuronal damage, cerebral edema, and neurobehavioral performances of MCAO mice.