Breaking the immune barrier: construction of cartilaginous organoids using alpha-1,3-galactosyltransferase-deficient pig cartilage-derived particles.

BACKGROUND: Articular cartilage injuries exhibit limited self-repair capacity due to avascularity and other intrinsic properties, leading to high disability rates and posing clinical challenges. In recent years, cartilaginous organoids (CORGs) have emerged as a promising tissue engineering strategy, offering new hope for cartilage regeneration and repair. However, biomaterials used in constructing CORGs still face challenges such as immunogenicity and biocompatibility during clinical translation. In particular, xenogeneic biomaterials, which contain natural antigens like the α-1,3-galactose (α-Gal) epitope, are prone to trigger severe host immune rejection. Gene editing technology, especially knocking out the gene encoding α-1,3-galactosyltransferase (GGTA1), holds promise for producing low-immunogenicity donor animals, such as α-Gal knockout pigs (α-Gal KO pigs).

MAIN BODY: In this study, through in vitro and in vivo experiments, a humanized mouse subcutaneous implantation model was established to verify the low immunogenicity of cartilage tissues from α-Gal KO pigs. Subsequently, cartilage-derived particles (CDPs) were prepared from α-Gal KO pig cartilage and further used to construct CORGs. Finally, the ability of these CORGs to form new cartilaginous tissue ectopically was validated in a nude mouse subcutaneous model.

CONCLUSIONS: This study explores the low immunogenicity of gene-edited porcine cartilage tissue and constructs a novel xenogeneic dECM-based cartilage organoid with ectopic chondrogenic capability. This approach is expected to overcome immune rejection barriers and pave a novel strategic avenue for the clinical translation of cartilage organoids.