"Damage to the central nervous system (CNS) often leads to persistent functional deficits, causinggreat individual suffering and enormous cost to society. The manifestation of these deficits isbelieved to be associated with the scar tissue that forms locally at lesions, causing permanent tissuealteration and blocking regeneration.Research on CNS scar tissue has primarily focused on astrocytes and it is often referred to as theglial scar. However, although it has received much less attention, there is also a connective tissue orstromal, non-glial, component of the scar.While studying spinal cord injury-induced scarring, I recently discovered a new subpopulation ofperivascular cells, named type A pericytes, as a major source of connective scar tissue. Type Apericytes are embedded in the vascular wall but proliferate and leave the blood vessel upon injury,differentiating into fibroblast-like cells that deposit extracellular matrix to seal the lesion and formthe persistent stromal scar core.The aim of the proposal is to determine whether type A pericytes are a general source ofpathological connective tissue in the CNS, to understand the nature of type A pericytes, and touncover the signaling mechanisms mediating their recruitment. By comparing several differentinjury and disease models the proposed research intends to uncover common mechanisms ofscarring and fibrosis and to identify new targets for human treatment after CNS injury."