mRNA as a Novel Treatment Strategy for Hereditary Spastic Paraplegia Type 5

Area of Science:

• Neuroscience
• Genetics
• Biochemistry

Background:

• Hereditary Spastic Paraplegia type 5 (SPG5) is a neurodegenerative disorder caused by mutations in the CYP7B1 gene.
• CYP7B1 deficiency leads to accumulation of neurotoxic oxysterols, such as 25-hydroxycholesterol and 27-hydroxycholesterol, which can cross the blood-brain barrier.
• Current therapeutic strategies for SPG5 are limited.

Purpose of the Study:

• To investigate the potential of messenger RNA (mRNA) therapy for SPG5 by studying the intravenous administration of CYP7B1 mRNA.
• To assess the efficacy and safety of CYP7B1 mRNA in reducing neurotoxic oxysterols in a mouse model lacking the endogenous Cyp7b1 gene.

Main Methods:

• Intravenous injection of formulated mouse and human CYP7B1 mRNA into mice with a genetic deficiency in Cyp7b1.
• Measurement of oxysterol levels in liver, serum, and brain following single and repetitive mRNA administrations.
• Pharmacokinetic analysis to determine the duration of mRNA efficacy.

Main Results:

• A single dose of CYP7B1 mRNA significantly reduced oxysterols in the liver and serum within 2 days.
• Human CYP7B1 mRNA demonstrated sustained oxysterol reduction for at least 5 days after a single injection.
• Repetitive mRNA treatments were safe for up to 17 days and reduced neurotoxic oxysterols in liver, serum, and to some extent, the brain.

Conclusions:

• Intravenous administration of CYP7B1 mRNA is a viable strategy for reducing neurotoxic oxysterols in SPG5.
• mRNA therapy demonstrates potential as a novel therapeutic approach for patients with Hereditary Spastic Paraplegia type 5.
• Further research is warranted to explore the clinical application of mRNA-based therapies for SPG5.