Abstract
In gene therapy, sensory neurons have been shown to be sensitive to toxicity induced by high doses of adeno-associated virus (AAV) in blood and cerebrospinal fluid, particularly in the dorsal root ganglion (DRG). Toxicity is generally characterized by necrosis and axonopathy in the DRG, and axonal degeneration in the spinal cord and peripheral nerves. As the use of AAV-based therapies continues to grow exponentially, the development of a rapid and adaptable model to assess DRG toxicity is essential to progress In this work, 6-week-old mice were treated intrathecally with an AAV-miR-SOD1 vector known to induce DRG toxicity. These mice were subjected to transcriptomic, physiological and behavioral studies to elucidate transcriptomic alterations and the functional consequences of neuronal and axonal damage. In all our studies, increased serum levels of neurofilament (NfL) confirmed pathology in the DRG, in levels comparable to previous studies. Single nucleus RNA sequencing (snRNA-seq) revealed a reduced population of neurons and Schwann cells, an increase in fibroblasts and immune cells, and the emergence of a population of activated satellite glial cells. Enrichment analysis revealed, firstly, developmental and neurogenesis processes in activated satellite glial cells and, secondly, a gene signature in immune cells indicative of inflammation. Functionally, the mice suffered from reduced muscle strength, the emergence of hind limb clasping, decreased body weight and reduced survival. Some of these findings correlated with serum NfL levels. These studies provided mechanistic and cell-specific functional information in response to AAV-induced DRG toxicity in mice. Mice have proved to be a valuable and effective model, which will contribute to the design and screening of future gene therapies for central nervous system diseases.Translated with DeepL.com (free version)