Small molecules restore the function of mutant CLC5 associated with Dent disease

Area of Science:

• Nephrology
• Molecular Biology
• Pharmacology

Background:

• Dent disease type 1 is a genetic kidney disorder caused by mutations in the CLCN5 gene, which encodes the CLC5 chloride channel.
• Mutations in CLCN5 lead to dysfunctional CLC5 protein, affecting kidney function and causing symptoms like nephrocalcinosis and renal failure.
• The CLC5 protein functions as a 2Cl-/H+ exchanger, crucial for proper kidney tubule function.

Purpose of the Study:

• To investigate the therapeutic potential of small molecules, specifically 4-phenylbutyrate (4PBA) and 2-naphthoxyacetic acid (2-NOAA), for Dent disease type 1.
• To assess the impact of 4PBA and 2-NOAA on the expression and function of mutant CLC5 proteins.
• To evaluate the safety and efficacy of these compounds in cellular models of Dent disease.

Main Methods:

• Utilized whole-cell patch-clamp electrophysiology to measure CLC5 channel function in cells expressing mutant CLC5 proteins.
• Employed Western blot analysis to determine the expression levels of CLC5 protein in treated cells.
• Assessed cell viability following treatment with 4PBA and 2-NOAA to evaluate potential toxicity.

Main Results:

• Both 4PBA and 2-NOAA treatments were found to restore the reduced function and expression of non-Class I CLC5 mutants.
• Cell viability was significantly reduced in cells treated with 2-NOAA, indicating potential toxicity.
• 4PBA, a FDA-approved drug, showed promise in restoring mutant CLC5 function without apparent toxicity in this study.

Conclusions:

• 4-phenylbutyrate (4PBA) demonstrates significant potential as a therapeutic agent for Dent disease type 1 by improving mutant CLC5 protein function and expression.
• 2-naphthoxyacetic acid (2-NOAA) also restored CLC5 function but exhibited cytotoxicity, limiting its therapeutic applicability.
• These findings suggest that 4PBA could offer a viable treatment strategy for patients with Dent disease type 1, warranting further clinical investigation.