Three-dimensional reconstruction of degenerated corticospinal tracts from TDP-43 transgenic mice using clearing technique

HR QUINTÁ; P SILVA; JM PASQUINI; L MULLER IGAZ

Mar del Plata, Argentina

Congreso; Sociedad Argentina de Investigación en Neruociencias; 2015

SAN

Mislocalization and aggregation of the protein TDP-43 are hallmark features of the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). We have previously shown in mice that inducible overexpression of a cytoplasmically-localized form of TDP-43 (TDP-43-ΔNLS) in forebrain neurons evokes neuropathological changes that recapitulate several features of TDP-43 proteinopathies. Moreover, we recently described profound behavioral deficits in these mice, including motor, cognitive and social phenotypes. Some of these alterations were reversed upon transgene repression. Here, we describe the use of a novel approach to study the anatomo-pathological correlates of these changes, combining a cost-effective unsectioned brain/spinal cord clearing technique, fluoroRuby staining, one-photon confocal microscopy and three dimensional reconstruction to study the morphological changes in motor cortex (MC) and corticospinal tract (CST) of TDP-43 transgenic mice. Our immediate goals are to study the degree of CST degeneration as well as MC integrity and to analyze if the reversible motor phenotypes can be associated with axonal regeneration and sprouting in these structures. The application of this combined approach allows for evaluation of the damage caused by TDP-43 manipulation along the entire affected pathway, and to help elucidating the mechanisms underlying the motor phenotype recovery after transgene suppression, with implications for ALS/FTD.