AUTHOR=Phillips Priscilla L. , Wu Xiao-jun , Reyes Leticia 

TITLE=Differential affinity chromatography reveals a link between Porphyromonas gingivalis–induced changes in vascular smooth muscle cell differentiation and the type 9 secretion system

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=Volume 12 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.983247

DOI=10.3389/fcimb.2022.983247

ISSN=2235-2988

ABSTRACT=Porphyromonas gingivalis is implicated in adverse pregnancy outcome. We previously demonstrated that intrauterine infection with various strains of P. gingivalis impairs the physiologic remodeling of the uterine spiral arteries (IRSA) during pregnancy, which underlies the major obstetrical syndromes. Women diagnosed with IRSA also have a greater risk for premature cardiovascular disease in later life. Dysregulated plasticity of vascular smooth muscle cells (VSMC) is present in both IRSA and premature cardiovascular events. We hypothesized that VSMC could serve as bait to identify P. gingivalis proteins associated with dysregulated VSMC plasticity as seen in IRSA. We first confirmed that dams with P. gingivalis A7UF-induced IRSA also show perturbed aortic smooth muscle cell (AoSMC) plasticity along with P. gingivalis colonization of the tissue. In vitro infection of AoSMC with IRSA-inducing strain A7UF also perturbed AoSMC plasticity that did not occur with infection by nonIRSA-inducing strain W83.  Far-western blotting with strain W83 and strain A7UF showed a differential binding pattern to rat aorta and primary rat AoSMC.  Affinity chromatography/pull-down assay combined with mass spectrometry was used to identify P. gingivalis/AoSMC protein interactions specific to IRSA. Membrane proteins with high binding affinity to AoSMC were identified in the A7UF pull-down but not in the W83 pull-down, most of which were outer membrane components of the Type 9 secretion system (T9SS) and T9SS cargo proteins. Additional T9SS cargo proteins were detected in greater abundance in the A7UF pull-down eluate compared to W83. None of the proteins enriched in the W83 eluate were T9SS components nor T9SS cargo proteins despite their presence in the prey preparations used in the pull-down assay. In summary, differential affinity chromatography established that components of IRSA-inducing P. gingivalis T9SS as well as its cargo directly interact with AoSMC, which may play a role in infection-induced dysregulation of vascular smooth muscle cell plasticity. The possibility that the T9SS is involved in microbial manipulation of host cell events important for cell differentiation and tissue remodeling would constitute a new virulence function for this system.