Parkinson's disease motor symptoms rescue by CRISPRa‐reprogramming astrocytes into GABAergic neurons

Abstract

Direct reprogramming based on genetic factors resembles a promising strategy to replace lost cells in degenerative diseases such as Parkinson's disease. For this, we developed a knock‐in mouse line carrying a dual dCas9 transactivator system (dCAM) allowing the conditional in vivo activation of endogenous genes. To enable a translational application, we additionally established an AAV‐based strategy carrying intein‐split‐dCas9 in combination with activators (AAV‐dCAS). Both approaches were successful in reprogramming striatal astrocytes into induced GABAergic neurons confirmed by single‐cell transcriptome analysis of reprogrammed neurons in vivo. These GABAergic neurons functionally integrate into striatal circuits, alleviating voluntary motor behavior aspects in a 6‐OHDA Parkinson's disease model. Our results suggest a novel intervention strategy beyond the restoration of dopamine levels. Thus, the AAV‐dCAS approach might enable an alternative route for clinical therapies of Parkinson's disease.

A miR-124-mediated post-transcriptional mechanism controlling the cell fate switch of astrocytes to induced neurons

“…However, the in vivo neurogenic capacity of miR-124 on its own has not been evaluated up to now. In the last years, the functional restoration of disease-related symptoms upon direct reprogramming has been reported ( Giehrl-Schwab et al., 2022 ; Qian et al., 2020 ; Zhou et al., 2020 ; Wu et al., 2020 ; Chen et al., 2019 ), supporting the therapeutic promise of in vivo direct reprogramming to restore impaired neuronal circuits ( Bocchi et al., 2022 ). However, certain AAV-based strategies and astrocyte-lineage-tracing approaches have been very recently put under question for their capacity to confer neurogenic reprogramming ( Wang et al., 2021 ).…”

A miR-124-mediated post-transcriptional mechanism controlling the cell fate switch of astrocytes to induced-neurons

“…For this, we employed two different viral-based approaches, using either lentiviruses or the more recently used AAVs and corroborated the latter approach with BrdU administration during the peak period of trauma-induced astrogliosis. The last years, the functional restoration of diseaserelated symptoms upon direct reprogramming has been reported (Giehrl-Schwab et al 2022;Qian et al 2020;Zhou et al 2020;Z. Wu et al 2020;Y.…”

Astrocytes as master modulators of neural networks: Synaptic functions and disease‐associated dysfunction of astrocytes

“…In addition, astrocytes have been targeted for cellular reprogramming into neuronal subtypes to correct for diseased or lost neurons in neurodegenerative disorders, such as in Parkinson's disease. 199,200 While such glial-to-neuronal phenoconversion approaches are both controversial and at an early stage in development, [201][202][203] they offer promise toward the treatment of a broad variety of neurological disorders.…”

“…More broadly, with the advent of in vivo gene editing via CRISPR and/or base editors coupled with the cell‐type specific delivery of those products, we may now consider altering the genome/epigenome of astrocytes for therapeutic purposes. In addition, astrocytes have been targeted for cellular reprogramming into neuronal subtypes to correct for diseased or lost neurons in neurodegenerative disorders, such as in Parkinson's disease 199,200 . While such glial–to–neuronal phenoconversion approaches are both controversial and at an early stage in development, 201–203 they offer promise toward the treatment of a broad variety of neurological disorders.…”