MicroRNA-544 inhibits inflammatory response and cell apoptosis after cerebral ischemia reperfusion by targeting IRAK4.

Objective: Stroke remains the most common malignant cerebrovascular event in the world. The correlation between the expression of miR-544 and the degree of cerebral ischemia reperfusion (CIR) injury has not been well recognized in recent years. This study focuses on the effect of miR-544 on inflammation and apoptosis after CIR.
Patients and Methods: Plasma expression of miR-544 in ischemic stroke (IS) patients and healthy controls was determined by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). The effects of miR-544 on cerebral infarction and neurological deficits were verified in vitro by tail vein injection of Ago-miR-544. Western blotting was utilized to examine protein expressions of key proteins involving in inflammation and apoptosis in mouse brain. Western blotting, immunofluorescence staining and luciferase assays were used to demonstrate whether miR-544 influences the expression of interleukin-1 receptor-associated kinase 4 (IRAK4), downstream inflammatory and apoptosis-related proteins.
Results: MiR-544 was found decreased in peripheral blood of IS patients compared with healthy controls. MiR-544 has been shown to relieve neurological deficits and reduce the volume of cerebral infarction in mice. Overexpression of miR-544 ameliorated the inflammation and apoptotic responses in brain tissue after ischemia reperfusion by down-regulating the expression of IRAK4, whereas the low expression was opposite in vivo and in vitro.
Conclusions: We found that miR-544 may participate in controlling inflammation and apoptosis after ischemia-reperfusion by targeting IRAK4, providing possible diagnostic indicators and therapeutic targets for IS.