AUTHOR=Kang Wenyan , Ji Xiaoli , Zhang Xiujun , Tang Di , Feng Qiang 

TITLE=Persistent Exposure to Fusobacterium nucleatum Triggers Chemokine/Cytokine Release and Inhibits the Proliferation and Osteogenic Differentiation Capabilities of Human Gingiva-Derived Mesenchymal Stem Cells

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=9

YEAR=2019

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2019.00429

DOI=10.3389/fcimb.2019.00429

ISSN=2235-2988

ABSTRACT=<p><italic>Fusobacterium nucleatum</italic> is one of the most frequent pathogenic bacteria causing periodontitis. The direct effect of <italic>Fusobacterium nucleatum</italic> (<italic>F. nucleatum</italic>) on oral stem cells has rarely been reported. In this study, we aimed to evaluate how gingiva-derived mesenchymal stem cells (GMSCs) respond to a direct challenge with <italic>F. nucleatum</italic>. GMSCs were isolated by the limiting dilution method and exposed to <italic>F. nucleatum</italic> at various multiplicities of infection (MOIs; <italic>F. nucleatum</italic>:cell ratios of 10:1, 50:1, and 100:1) for 24 h to 4 weeks. Our results indicated that <italic>F. nucleatum</italic> significantly inhibited cell proliferation in a dose-dependent manner and promoted cell migration and the release of chemokines/cytokines, such as CCL2, CXCL1, and IL-6. Additionally, <italic>F. nucleatum</italic> inhibited GMSC osteogenic differentiation partly by decreasing alkaline phosphatase (ALP) activity, mineralized nodule formation, and osteogenesis-related gene and protein expression. RNA-sequencing analyses indicated that <italic>F. nucleatum</italic> time-dependently activated cellular signaling pathways during the process of osteogenic differentiation. A total of 64 cell differentiation-related genes were found to be differentially expressed between non-infected and <italic>F. nucleatum</italic>-infected GMSCs at 3, 7, 14, and 21 d. Intriguingly, we discovered that the 64 cell differentiation-related differentially expressed genes (DEGs) were significantly enriched in cancer-related pathways, such as bone cancer, osteosarcoma and bone marrow cancer, which provides new insight into tumorigenesis during the process of GMSC osteogenic differentiation. In conclusion, this study demonstrates that persistent exposure to <italic>F. nucleatum</italic> promotes cell migration and chemokine/cytokine release and inhibits the proliferation and osteogenic differentiation of GMSCs. Our study provides a novel and long-time bacteria-cell co-culture <italic>in vitro</italic> model and makes a foundation for the future mechanistic studies of GMSCs under <italic>F. nucleatum</italic> infection.</p>