Endothelial Cells and Astrocytes: A Concerto en Duo in Ischemic Pathophysiology
Figure 2
(a) Schematic drawing of the aquaporin homotetramer assembly within the lipid membrane: the central pore is proposed to be permeable to cations and gases (green arrows). Each individual aquaporin facilitates bidirectional water movement depending on the osmotic gradient (blue arrows). (b) AQP4 homotetramer is assembled in a higher structure named orthogonal array of particles (OAPs). Two isoforms of AQP4, AQP4-M1 (purple circles) and AQP4-M23 (blue circles) isoforms, contribute to the formation of OAPs. In vitro experiment showed that higher expression of AQP4-M23 contributes to the formation of larger OAPs. (c) Increase of AQP4-M1 induced disruption of OAPs. Recent knowledge on AQP leads us to hypothesize that the large OAPs contribute to gas and cation diffusion in the astrocyte membranes through central pores (green arrows).
