HMGB1 and Stroke: Related to this, our group has recently demonstrated that TLR4 activation with ligands such as high mobility group box 1 (HMGB1), which is released into the CSF after stroke, drives increased proliferation of neural progenitor cells (NPCs) in this setting, while also promoting differentiation of type-C progenitor cells into migrating neuroblasts (Palma-Tortosa et al., 2019).