Inhibition of Rho-Associated Kinases ROCK1 and ROCK2 as a Therapeutic Strategy to Reactivate the Repressed FXN Gene...

Area of Science:

• Neuroscience
• Genetics
• Biochemistry

Background:

• Friedreich ataxia (FA) is an inherited neurodegenerative disorder caused by reduced expression of the FXN gene.
• FXN gene repression leads to mitochondrial dysfunction and severe neurological and cardiac symptoms.
• Identifying therapeutic targets to restore FXN expression is crucial for FA treatment.

Purpose of the Study:

• To identify kinases that regulate FXN gene expression using a candidate-based RNAi screen.
• To investigate the role of Rho-associated coiled-coil containing protein kinase (ROCK) in FXN repression.
• To evaluate the therapeutic potential of ROCK inhibitors for Friedreich ataxia.

Main Methods:

• Performed a candidate-based RNAi screen to identify kinases affecting FXN expression.
• Utilized short hairpin RNA (shRNA) to knock down ROCK1 and ROCK2 in patient-derived cells.
• Administered ROCK inhibitors (belumosudil, fasudil) to cell cultures and transgenic FA mice.
• Assessed FXN mRNA and frataxin protein levels, mitochondrial function, and motor performance.

Main Results:

• Rho kinase (ROCK)1 was identified as a key repressor of FXN expression.
• Knockdown of ROCK1 or ROCK2 increased FXN mRNA and frataxin protein levels in FA cells.
• ROCK inhibitors (belumosudil, fasudil) reactivated FXN expression and ameliorated mitochondrial defects in vitro.
• In vivo treatment of FA mice with ROCK inhibitors improved mitochondrial function and motor deficits.

Conclusions:

• ROCK kinases are critical regulators of FXN gene expression and represent therapeutic targets for FA.
• FDA-approved ROCK inhibitors demonstrate preclinical efficacy for treating Friedreich ataxia.
• Repurposing ROCK inhibitors offers a promising strategy for FA treatment.