MMP9 and multiple sclerosis: A variety of inflammatory mediators have been suggested to impact the tight junction proteins to affect the BBB.[36] In addition, extracellular matrix components have been observed to be elevated in multiple sclerosis, specifically at the basement membranes of cerebral vessels.[67] Here, we identified that MMP9, an extracellular matrix protease, was suppressed in microglia following upregulating miR‐126a‐5p.