DHH and multiple sclerosis: Next, we demonstrated that Dhh is severely down-regulated at the BBB under inflammatory conditions both in vitro using human brain microvascular endothelial cells (HBMECs) treated with interleukin-1β (IL-1β) (one of the main pro-inflammatory cytokine implicated in multiple sclerosis pathophysiology) (Fig 1C and S1 Data) and in vivo (Fig 1F and S1 Data) using a preclinical model of multiple sclerosis (MOG35-55) to induce chronic neuroinflammation in C57BL/6 mice.