An iPSC-derived model for drug screening in cerebral small vessel disease.

Despite the enormous health importance of cerebral small vessel disease (cSVD) there are few treatments available. A major limitation in screening new therapies is a lack of clinically relevant disease models. Induced pluripotent stem cell (iPSC) technology allows creation of in vitro models of the vascular unit, which is found to be affected in cSVD. Here we derived iPSC from skin biopsies obtained from patients with two of the most common monogenic forms of cSVD, HTRA1 mutations and COL4A1/2 mutations. iPSCs were differentiated into brain endothelial-like cells and mural cells and co-cultured in a transwell system to replicate the vascular unit. iPSC models derived from the two distinctive forms of monogenic cSVD demonstrated a common molecular phenotype characterised by tight junction defects, elevated actin stress fiber expression and mural cell loss, increased blood-brain barrier (BBB) permeability and elevated matrix metalloproteinase (MMP) levels. Moreover, the model was successfully optimised to a 96-well format to screen 13 MMP inhibitors, three of which effectively restored permeability to control levels. Our findings provide evidence that MMP inhibition could serve as a potential therapeutic strategy for cSVD as well as present a robust model to screen drugs in cSVD.