Deciphering cerebellar mitochondrial alterations in Rett Syndrome

Mutations in the X-linked gene encoding methyl-CpG binding protein 2 (Mecp2) can lead to the progressive neurodevelopmental disorder known as Rett syndrome (RTT), characterized by regression in motor, social and cognitive
skills, respiratory dysrhythmias and premature lethality. Although few symptomatic treatments exist, nowadays there is still no cure for this disease.
Mecp2 acts as transcriptional regulator and its mutations directly affect the expression of targeted transcripts, including mitochondrial (MT) genes. Cerebellum is one of brain regions with larger energy requirements. 43% of its ATP consumption occurs in the molecular layer, where the high-energy demanding parvalbumin (PV)-neurons are positioned. Compelling evidence indicates aberrant MT morphology and functionality in cerebellar biopsies of RTT patients. However, the cellular substrate of these modifications remains largely unknown. In adult cerebellum Mecp2 is preferentially expressed in PVpositive
cells. Hence, we hypothesize that RTT in PV-positive neurons might present a particular vulnerability to MT alterations. Thus, in this proposal I will implement a multidisciplinary approach to find candidate MT proteins differentially
regulated in cerebellar PV-positive neurons associated with the MT impairments observed in RTT. To tackle this aim, I will perform proteomic, functional and metabolomic studies in MT immunoprecipitates from cerebellar PV-positive neurons of RTT mice. This project will thus give raise to: i) the first exhaustive list of MT proteins dysregulated in these cells in RTT ii) identification of functional and metabolomic impairments affecting MT functionality in PV-positive cells of RTT mice.
MITORett project will be a breakthrough in our understanding of RTT and it will provide novel insights into the pathophysiology of this disease by unveiling potential therapeutical targets to focus the forthcoming experiments dedicated
on the design of more selective drugs/treatments.