Activation of TrkB-Akt signaling rescues deficits in a mouse model of SCA6.

Cook, Anna A; Jayabal, Sriram; Sheng, Jacky; Fields, Eviatar; Leung, Tsz Chui Sophia; Quilez, Sabrina; McNicholas, Eileen; Lau, Lois et al. · Sci Adv · 2022

basic_science · Level V

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Abstract

Spinocerebellar ataxia type 6 (SCA6) is a neurodegenerative disease resulting in motor coordination deficits and cerebellar pathology. Expression of brain-derived neurotrophic factor (BDNF) is reduced in postmortem tissue from SCA6 patients. Here, we show that levels of cerebellar BDNF and its receptor, tropomyosin receptor kinase B (TrkB), are reduced at an early disease stage in a mouse model of SCA6 (SCA6<sup>84Q/84Q</sup>). One month of exercise elevated cerebellar BDNF expression and improved ataxia and cerebellar Purkinje cell firing rate deficits. A TrkB agonist, 7,8-dihydroxyflavone (7,8-DHF), likewise improved motor coordination and Purkinje cell firing rate and elevated downstream Akt signaling. Prolonged 7,8-DHF administration persistently improved ataxia when treatment commenced near disease onset but was ineffective when treatment was started late. These data suggest that 7,8-DHF, which is orally bioavailable and crosses the blood-brain barrier, is a promising therapeutic for SCA6 and argue for the importance of early intervention for SCA6.