Rescuing the cytolytic function of APDS1 patient T cells via TALEN-mediated PIK3CD gene correction

Area of Science:

• Immunology
• Genetics
• Molecular Biology

Background:

• Activated phosphoinositide 3-kinase δ syndrome type 1 (APDS1) is a severe combined immunodeficiency caused by gain-of-function mutations in the PIK3CD gene.
• Current therapeutic options for APDS1 are limited, highlighting the urgent need for novel treatment strategies.

Purpose of the Study:

• To investigate the potential of gene editing as a therapeutic approach for APDS1 by correcting the mutated PIK3CD gene.
• To assess the functional restoration of immune cells following gene correction in APDS1 patients.

Main Methods:

• Utilized TALEN-mediated gene editing to correct the PIK3CD mutation in T cells from APDS1 patients.
• Assessed PI3K/AKT signaling pathway activity through phospho-AKT levels.
• Evaluated cytotoxic functions of CD8+ T cells.
• Performed single-cell RNA sequencing to analyze transcriptomic changes in edited T cells.

Main Results:

• TALEN-mediated gene correction normalized phospho-AKT levels in APDS1 T cells under both basal and stimulated conditions.
• Correction of PI3K signaling correlated with the restoration of CD8+ T cell cytotoxic functions.
• Single-cell RNA sequencing demonstrated corrected transcriptomic signatures associated with CD8+ effector memory and proliferating T cells.

Conclusions:

• Gene editing of the PIK3CD gene is a viable proof-of-concept for treating APDS1.
• This approach shows potential for restoring immune cell function and offers a promising avenue for developing a gene therapy for APDS1.