Involvement of aquaporin‐4 in laminin‐enhanced process formation of mouse astrocytes in 2D culture: Roles of dystroglycan and α‐syntrophin in aquaporin‐4 expression. Issue 4 (31st October 2018)

• Record Type: Journal Article
• Authors: Sato, Junya; Horibe, Sayo; Kawauchi, Shoji; Sasaki, Naoto; Hirata, Ken‐ichi; Rikitake, Yoshiyuki
• Is Part Of: Journal of neurochemistry. Volume 147:Issue 4(2018)
• Page Start: 495
• Page End: 513
• Publication Date: 2018-10-31
• Subjects: differentiation -- dystrophin–glycoprotein complex -- endfoot -- focal adhesion kinase -- neurosphere; Neurochemistry -- Periodicals; 616.8042
• DOI: 10.1111/jnc.14548
• Languages: English
• ISSNs: 0022-3042

Abstract

Abstract: In the central nervous system, astrocytes extend endfoot processes to ensheath synapses and microvessels. However, the mechanisms underlying this astrocytic process extension remain unclear. A limitation of the use of 2D cultured astrocytes for such studies is that they display a flat, epithelioid morphology, with no or very few processes, which is markedly different from the stellate morphology observed in vivo . In this study, we obtained 2D cultured astrocytes with a rich complexity of processes using differentiation of neurospheres in vitro . Using these process‐bearing astrocytes, we showed that laminin, an extracellular matrix molecule abundant in perivascular sites, efficiently induced process formation and branching. Specifically, the numbers of the first‐ and second‐order branch processes and the maximal process length of astrocytes were increased when cultured on laminin, compared with when they were cultured on poly‐L‐ornithine or type IV collagen. Knockdown of dystroglycan or α‐syntrophin, constituent proteins of the dystrophin–glycoprotein complex that provides a link between laminin and the cytoskeleton, using small interference RNAs inhibited astrocyte process formation and branching, and down‐regulated expression of the water channel aquaporin‐4 (AQP4). Direct knockdown and a specific inhibitor of AQP4 also inhibited, whereas over‐expression of AQP4 enhanced astrocyte process formation and branching. Knockdown of AQP4 decreased phosphorylation of focal adhesion kinase (FAK) that is critically implicated in actin remodeling. Collectively, these results indicate that the laminin–dystroglycan–α‐syntrophin–AQP4 axis is important for process formation and branching of 2D cultured astrocytes. Open Practices: This article has received a badge for *Open Materials * because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found athttps://cos.io/our-services/open-science-badges/ . Read the Editorial Highlight for this article on page 436 . Abstract : Proposed model of laminin‐enhanced astrocytic process formation. Laminin interacts with dystroglycan (DG), which indirectly interacts with α‐syntrophin (Syn) through Dp71 and α‐dystrobrevin‐1 (DB). Signals from DG and Syn regulate aquaporin‐4 (AQP4) mRNA expression, and AQP4 that is anchored by Syn, regulates phosphorylation of focal adhesion kinase (FAK). Thus, laminin enhanced astrocytic process formation through the DG–Syn–AQP4 axis. Open Science: This manuscript was awarded with the Open Materials Badge. For more information see:https://cos.io/our-services/open-science-badges/ Read the Editorial Highlight for this article on page 436 .