MicroRNA 320a functions as a novel endogenous modulator of aquaporins 1 and 4 as well as a potential therapeutic target in cerebral ischemia.

Aquaporins facilitate efficient diffusion of water across cellular membranes, and water homeostasis is critically important in conditions such as cerebral edema. Changes in aquaporin 1 and 4 expression in the brain are associated with cerebral edema, and the lack of water channel modulators is often highlighted. Here we present evidence of an endogenous modulator of aquaporin 1 and 4. We identify miR-320a as a potential modulator of aquaporin 1 and 4 and explore the possibility of using miR-320a to alter the expression of aquaporin 1 and 4 in normal and ischemic conditions. We show that precursor miR-320a can function as an inhibitor, whereas anti-miR-320a can act as an activator of aquaporin 1 and 4 expressions. We have also shown that anti-miR-320a could bring about a reduction of infarct volume in cerebral ischemia with a concomitant increase in aquaporins 1 and 4 mRNA and protein expression.