Porphyromonas Gingivalis Survives In BMECs By Kgp Inhibiting Lysosomal Acidification

This study aimed to investigate Porphyromonas gingivalis (P. gingivalis) persistence in human brain microvascular endothelial cells (BMECs), its impact on cellular lysosomal acidification and regulatory mechanisms, given that brain-resident P. gingivalis has been demonstrated to play a significant role in cognitive impairment and blood–brain barrier (BBB) permeability increase. The survival status of P. gingivalis within BMECs was observed. LysoTracker was used to examine the impact of P. gingivalis and gingipains on cellular lysosomal acidification. The number of live P. gingivalis internalized BMECs, the effects of P. gingivalis and gingipains on the expression level of ATPase H+ Transporting V0 Subunit D1 (ATP6V0D1) and lysosomal-associated membrane protein 1 (LAMP1), and the colocalization of Kgp with ATP6V0D1, LAMP1 proteins were detected. The role of Kgp in P. gingivalis intracellular survival was elucidated through KYT-36, a specific Kgp enzymatic activity inhibitor. 1.P. gingivalis survived in BMECs cells and was capable of entering lysosomes, promoting cellular autophagosome generation but blocking autophagic flow (P <0.01). 2. P. gingivalis and gingipains inhibited BMECs lysosomal acidification (P <0.01), decreased the protein expression of ATP6V0D1 and LAMP1(P <0.05), while the number of live P. gingivalis in BMECs reduced when cellular lysosomal acidification was exacerbated(P <0.01). 3.Kgp directly degraded ATP6V0D1, LAMP1 protein(P <0.01), inhibited BMECs lysosomal acidification(P <0.01). Kgp enzymatic activity promot the survival of P. gingivalis in BMECs, which may contribute to the subsequent BBB permeability increase and cognitive impairment.