New retrograde AAV9 variant for excItability modulation of motoneurons and translational ALS modeling in vivo.

• Applicant: Professor Francesco Roselli, Ph.D.
• Subject Area: Molecular and Cellular Neurology and Neuropathology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 545426613

Degeneration of Motoneurons (MN) in Amyotrophic Lateral Sclerosis (ALS) is believed to be related to changes in MN excitability, but both hypo- and hyper-excitability are hypothesized to have a pathogenic role. This inconsistency is due to the hurdles to achieve a systematic modulation of physiological firing properties of MN in vivo and to the limited number of ALS-related mutations that have been studied in animal models. Here we introduce the Nefertiti AAV9, a new capsid variant that enables efficient and selective transfection of MN in adult mice upon intramuscular injection. The Nefertiti variant allows the reliable genetic access to MN of a specific pool in vivo and enables the electrophysiological recording of their characteristics in vivo. We propose to exploit these properties to demonstrate the modulation of MN firing properties by targeting K+ and Na+ conductances by ShRNA. Thereafter we will exploit these tools to change the firing properties of MN in the SOD1(G93A) ALS model and verifying the impact on disease markers, transcriptome signatures and electrophysiological properties. Finally we will use the Nefertiti variant to express in MN four ALS-related mutant proteins (SOD1, FUS, SPLTC1 and ANXA11) and demonstrate the changes in excitability and excitation. We will be able to ascertain the effect of bidirectional excitability changes verified by electrophysiology on MN vulnerability and whether multiple ALS mutations produce similar effects. By so doing we will validate the Nerfertiti AAV as a good candidate for applications in gene therapy, personalized medicine and neurophysiology.

• DFG Programme: Research Grants
• International Connection: France
• Partner Organisation: Agence Nationale de la Recherche / The French National Research Agency
• Cooperation Partner: Professor Dr. Daniel Zytnicki