Gingipain regulates isoform switches of PD-L1 in macrophages infected with Porphyromonas gingivalis

Abstract

Periodontal pathogen Porphyromonas gingivalis(Pg) is believed to possess immune evasion capabilities, but it remains unclear whether this immune evasion is related to host gene alternative splicing (AS). In this study, RNA-sequencing (RNA-seq) revealed significant changes in both AS landscape and transcriptomic profile of macrophages following Pg infection with/without knockout of gingipain (a unique toxic protease of Pg). Pg infection increased the programmed death ligand 1 (PD-L1) transcripts expression and selectively upregulated a specific coding isoform that more effectively binds to programmed cell death protein 1 (PD-1) receptors on T cells, thereby inhibiting immune function. Biological experiments confirmed these results and demonstrated that the AS switch of PD-L1 was gingipain-dependent. AlphaFold 3 predictions indicated that the protein docking compatibility between PD-1 and Pg-upregulated PD-L1 isoform was over 80% higher than another coding isoform. These findings suggest that Pg employs gingipain to modulate the AS of PD-L1, facilitating immune evasion.