Fig. 2

ECM collagen in healthy and diseased CNS tissue. (A) In healthy CNS tissue, the collagen ECM landscape is highly dynamic. In the basal lamina, collagen IV, produced by endothelial cells, astrocytes, and vascular pericytes, creates a main structural scaffold to which other ECM-associated proteins can bind and interact. In the extracellular space, collagen content varies through time. In early CNS development, collagens I, IX, and XVIII are important for differentiation and vessel development. In PNNs, collagen XIX appears to play a role in long-term memory. Matrix metalloproteinases (MMPs) are key to collagen turnover. (B) In diseased tissue, damaged collagen is present due to up-regulation of MMPs. Damage to collagen in the basal lamina contributes to the breakdown of the blood-brain barrier, leading to infiltration of peripheral immune cells. Increased deposition of collagen by glial cells and the breakdown of collagen by MMPs alters the biomechanical properties and ligand binding capacity of the ECM leading to increased inflammation and degeneration of neurons. Created with Biorender.com