Splice-correcting oligonucleotides restore BTK function in X-linked agammaglobulinemia model

Area of Science:

• Genetics
• Immunology
• Molecular Biology

Background:

• X-linked agammaglobulinemia (XLA) is an inherited immunodeficiency caused by mutations in the Bruton's tyrosine kinase (BTK) gene.
• Many XLA mutations disrupt BTK pre-mRNA splicing, leading to impaired B cell development and function.

Purpose of the Study:

• To evaluate the therapeutic potential of antisense, splice-correcting oligonucleotides (SCOs) for XLA by targeting mutated BTK transcripts.
• To develop and validate an animal model for XLA to test SCO efficacy.

Main Methods:

• Optimized SCOs using various backbone chemistries (2'-O-methyl, LNA, PMO).
• Engineered a transgenic mouse model with a mutated human BTK gene on a Btk knockout background.
• Assessed SCO ability to correct BTK splicing and restore protein function in B lymphocytes and patient-derived cells.

Main Results:

• BTK-specific SCOs successfully corrected aberrant BTK splicing in B lymphocytes, including pro-B cells, in the mouse model.
• Restored BTK mRNA expression led to functional protein recovery, evidenced by enhanced lymphocyte survival and restored signaling upon B cell receptor stimulation.
• SCO treatment also corrected splicing and restored BTK expression in primary cells from XLA patients.

Conclusions:

• Antisense SCOs effectively restore BTK function by correcting aberrant splicing in XLA.
• BTK-targeting SCOs represent a promising strategy for personalized medicine approaches in treating XLA.