Membrane Associated RNA-Containing Vesicles Regulate Cortical Astrocytic Microdomain Calcium Transients in Awake Ischemic Stroke Mice.

Abstract

Astrocytic processes minutely regulate neuronal activity via tripartite synaptic structures. The precision-tuning of the function of astrocytic processes is garnering increasing attention because of its significance in promoting brain repair following ischemic stroke. Microdomain calcium (Ca) transients in astrocytic processes are pivotal for the functional regulation of these processes. However, the understanding of the alterations and regulatory mechanism of microdomain Catransients during stroke remains limited. In the present study, a fast high-resolution, miniaturized two-photon microscopy is used to show that the levels of astrocytic microdomain Catransients are significantly reduced in the peri-infarct area of awake ischemic stroke mice. This finding correlated with the behavioral deficits shown by these mice under freely-moving conditions. Mitochondrial Caactivity is an important factor driving the microdomain Catransients. DEAD Box 1 (DDX1) bound to circSCMH1 (a circular RNA involved in vascular post-stroke repair) facilitates the formation of membrane-associated RNA-containing vesicles (MARVs) and enhances the activity of astrocytic microdomain Catransients, thereby promoting behavioral recovery. These results show that targeting astrocytic microdomain Catransients is a potential therapeutic approach in stroke intervention.