MICRORNA DYSREGULATION CONTRIBUTES TO BRAIN MICROVASCULAR INJURY, VASCULAR REGENERATION, AND INFLAMMATORY RESPONSE BY TARGETING P38/MAPK

Zhaoqi Ding, Jian Yuan, Shimin Jin, Xiaodong Wang, Zhen’e Jin, Xiaoping Wang, Lei Hou, Rongxiao Dai^*

Department of Neurosurgery, Jiading District Central Hospital Affiliated Shanghai University of Medicine & Health Sciences

Objective: To investigate how microRNA dysregulation contributes to brain microvascular injury, vascular regeneration, and inflammatory response by targeting p38/MAPK. 

Methods: Brain microvascular endothelial Bend3 cells were selected for cell culture and various treatments. We obtained miRNA-451-overexpressing Bend3 cells (the miRNA-451 overexpression group), miRNA-451 control cells (the miRNA-451 control group), stable knockout miRNA-451 Bend3 cells (the miRNA-451 interference group), and miRNA-451 interference control cells (the miRNA-451 interference control group). The changes in cell proliferation, migration, and angiogenesis were compared between groups. The expression levels of PI3K, Akt, Erk, p38/MAPK, and MIF in each group of cells were compared. We randomly selected 60 SPF male C57BL/6 mice; these were divided into a sham operation group (stereotactic injection of 2 μL phosphate buffer into the brain), an miRNA-451 group (3μL miRNA-451 lentiviral solution injected into the brain stereotactically), and an miRNA-451 interference group (stereotactic injection of 2 μL miRNA-451 interference lentiviral fluid into the brain), with 20 mice in each group. We observed for neuron damage in the mouse hippocampus, the expression of blood-brain barrier-related protein ZO-1, and changes in inflammatory factors in the hippocampus of mice in each group. The expression changes of p38/mitogen-activated protein kinase (p38/MAPK) in each group of mice were compared. 

Results: Compared with the miRNA-451 control group and the miRNA-451 interference control group, there was no significant difference in the cell proliferation capacity of the miRNA-451 overexpression group and the miRNA-451 interference group at 12 hours. At 24h and 36h, the cell proliferation ability of the miRNA-451 overexpression group was significantly lower, while the cell proliferation ability of the miRNA-451 interference group was significantly increased (P<0.05). Compared with the miRNA-451 control group, the miRNA-451 overexpression group showed significantly reduced cell clone formation ability, cell migration ability, angiogenesis ability, p38/MAPK expression levels, and MIF expression levels (P<0.05). Compared with the miRNA-451 interference control group, the miRNA-451 interference group showed significantly higher cell formation ability, cell migration, angiogenesis, p38/MAPK expression levels, and MIF expression (P<0.05). In the sham operation group, the neuron cells were closely packed and uniformly distributed; the intercellular space was normal, with obvious Nissl bodies. Neuronal cells in the miRNA-451 overexpression group were similar to those in the sham operation group. In the miRNA-451 interference group, the neuronal cells were arranged loosely and in a disorderly manner; the neuron cell body showed irregularity, and the intercellular space increased significantly. Compared with the sham operation group and the miRNA-451 overexpression group, the expression levels of the blood-brain barrier-related protein ZO-1, inflammatory factors, and p38/MAPK in the miRNA-451 interference group were significantly higher (P<0.05). 

Conclusions: MicroRNA may contribute to brain microvascular injury, vascular regeneration, and the inflammatory response by targeting p38/MAPK.