PYK2 in the dorsal striatum of Huntington's disease R6/2 mouse model

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by HTT gene mutations.
• Molecular alterations, including transcriptional defects, contribute to HD pathophysiology.
• Previous studies indicated reduced PYK2 protein in the hippocampus of HD patients and models, with viral PYK2 improving hippocampal function.

Purpose of the Study:

• To investigate the role of PYK2 in the striatum, a brain region significantly affected in HD.
• To determine if restoring PYK2 levels in the striatum of HD mouse models could ameliorate disease phenotypes.

Main Methods:

• Assessed PYK2 mRNA and protein levels in the striatum and hippocampus of R6/2 HD mice and human HD patients.
• Utilized adeno-associated virus (AAV) vectors to express PYK2 in the dorsal striatum of R6/2 mice.
• Evaluated motor functions, including body weight, clasping, rotarod performance, and motor activity.

Main Results:

• PYK2 mRNA and protein levels were decreased in the striatum of R6/2 mice and HD patients.
• PYK2 knockout alone did not induce HD-like motor symptoms.
• AAV-mediated PYK2 expression in the striatum showed minimal improvement in R6/2 mouse phenotypes, with some effects potentially linked to expression in cholinergic interneurons.

Conclusions:

• PYK2 is downregulated in the striatum of HD patients and models, similar to the hippocampus.
• Unlike the hippocampus, restoring striatal PYK2 levels via viral vectors had a limited impact on the R6/2 mouse model's striatal phenotype.