Genetic Constructs for the Control of Astrocytes' Activity.

In the current review, we aim to discuss the principles and the perspectives of using the genetic constructs based on AAV vectors to regulate astrocytes' activity. Practical applications of optogenetic approaches utilizing different genetically encoded opsins to control astroglia activity were evaluated. The diversity of astrocytic cell-types complicates the rational design of an ideal viral vector for particular experimental goals. Therefore, efficient and sufficient targeting of astrocytes is a multiparametric process that requires a combination of specific AAV serotypes naturally predisposed to transduce astroglia with astrocyte-specific promoters in the AAV cassette. Inadequate combinations may result in off-target neuronal transduction to different degrees. Potentially, these constraints may be bypassed with the latest strategies of generating novel synthetic AAV serotypes with specified properties by rational engineering of AAV capsids or using directed evolution approach by searching within a more specific promoter or its replacement with the unique enhancer sequences characterized using modern molecular techniques (ChIP-seq, scATAC-seq, snATAC-seq) to drive the selective transgene expression in the target population of cells or desired brain regions. Realizing these strategies to restrict expression and to efficiently target astrocytic populations in specific brain regions or across the brain has great potential to enable future studies.