Rho Kinase Pathway Alterations in the Brain and Leukocytes in Huntington's Disease

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Huntington's disease (HD) is a fatal neurodegenerative disorder.
• It stems from an expanded polyglutamine tract in the huntingtin gene.
• Therapies targeting mutant huntingtin (mtHtt) and its toxic effects, such as Rho kinase pathway inhibition, are under investigation.

Purpose of the Study:

• To investigate the messenger RNA (mRNA) expression of Rho kinase pathway genes in Huntington's disease.
• To identify potential peripheral and translational biomarkers for HD.

Main Methods:

• Quantitative PCR (qPCR) was used to analyze mRNA expression of Rho kinase pathway genes (RhoA, ROCK1, PRK2, Profilin1, cofilin1, MYPT1, LIMK1).
• Studies were conducted on human blood leukocytes, postmortem brain tissue, and R6/2 HD mouse brain tissue.
• Western blot analysis was performed to confirm protein level changes.

Main Results:

• Significant increases in RhoA, ROCK1, PRK2, Profilin1, cofilin1, and MYPT1 mRNA were observed in HD blood compared to controls.
• Elevated expression of RhoA, ROCK1, PRK2, Profilin1, and MYPT1 mRNA was found in the frontal cortex of HD postmortem brains.
• ROCK1 and Profilin1 protein levels were also significantly increased in human postmortem tissues, correlating with mRNA levels.

Conclusions:

• The Rho kinase pathway is significantly upregulated in Huntington's disease.
• Specific Rho kinase pathway mRNAs show altered expression in HD patient blood and brain tissue, as well as in HD mouse models.
• These identified mRNAs represent potential peripheral biomarkers for HD diagnosis and translational markers for therapeutic development.