Fibroblast-derived laminin regulates blood-brain barrier integrity and fibroblast biology in hemorrhagic brain

Project Summary/Abstract The long-term objective of this application is to develop innovative therapies for intracerebral hemorrhage (ICH), which causes high rates of death and disability worldwide. This is consistent with the mission of NINDS. This proposal aims to investigate the biological functions of fibroblast-derived laminin in blood-brain barrier (BBB) repair and fibroblast biology after ICH and explore the underlying molecular mechanisms. In Aim 1, the function of fibroblast-derived laminin in ICH pathogenesis will be investigated in two clinically relevant ICH models using middle-aged transgenic mice with laminin deficiency in fibroblasts. In Aim 2, the function of fibroblast-derived laminin in BBB repair after ICH will be investigated both in vitro and in vitro. First, how loss of fibroblast-derived laminin affects BBB permeability and inflammatory cell infiltration after ICH will be examined (Aim 2A). Next, whether loss of fibroblast-derived laminin exacerbates BBB disruption via paracellular and/or transcellular mechanisms will be investigated (Aim 2B). Third, the receptors that mediate fibroblast-derived laminin’s “BBB-repairing” effect on endothelial cells will be identified using both pharmacological and genetic approaches (Aim 2C). In Aim 3, the function of fibroblast-derived laminin in fibroblast biology and fibrotic scar composition will be investigated. First, fibroblast biology (proliferation/apoptosis/migration), fibroblast morphology, and fibrotic scar components will be examined in vitro and in vivo (Aim 3A). Next, how exactly fibroblast-derived laminin regulates fibroblast biology and fibrotic scar composition will be explored by bulk and/or single-cell RNAseq analysis (Aim 3B). Third, the receptors that mediate these changes in fibroblasts will be identified using both pharmacological and genetic approaches (Aim 3C). Successful completion of this proposal will elucidate novel functions of fibroblast-derived laminin in BBB repair and fibroblast biology after ICH, identify the receptors that mediate these effects on both endothelial cells and fibroblasts, provide new molecular targets with therapeutic potential, and promote the development of innovative and effective treatments for ICH.