PRG2 Regulates Cell Skeleton Remodeling And Cell Migration

BackgroundGlobally,tuberculosis is one of the top ten causes of death（the death rate has been ranked before HIV since 2007）.The 2020 WHO Global Tuberculosis Report showed that in 2019 an estimated 10 million people worldwide were infected with tuberculosis,of which 8.4%of tuberculosis patients in China.BCG vaccine is a live attenuated strain derived from bovine Mycobacterium tuberculosis.This vaccine enhances the activity of macrophages and strengthen the macrophage killing,and it also activates T lymphocytes and promotes the cellular immune response in host.BCG vaccine has been widly used to prevent childhood tuberculous meningitis and miliary disease.but it has no protective effect on adults.Therefore,the in-depth study of the molecular mechanism of BCG-induced immune activation and response is still of great significance for tuberculosis privention.Bone marrow proteoglycan 2（PRG2）,also namely pro eosinophil major basic protein（pro MBP）,is the main component of the eosinophil crystal core.PRG2 may be involved in anti-parasitic defense mechanisms,such as cytotoxins and worm toxins,and immune hypersensitivity and other allergic diseases.However,the immune function of PRG2 in T cells is not yet known.Our previous research found that the in BCG-immunized mice CD4⁺T cells PRG2 interacted withγ-actin.Therefore,we will further explore the interaction between PRG2 and actin,and its effect on regulation of actin polymerization,cytoskeleton remodeling and T cell migration.Objective:This project aims to explore the mechanism by which PRG2 mediates cytoskeleton remodeling and cell migration in CD3⁺CD4⁺T cells.Methods:The target protein bound to PRG2 and its expression level were determined by Western Blot,co-immunoprecipitation,and confocal microscopy.Confocal microscopy and G-actin/F-actin separation experiments were used to detect the effect of PRG2 on the cytoskeleton remodeling.In vitro transwell experiment and in vivo adoptive transfer experiment were used to explore the effect of PRG2 on cell migration.Results:PRG2 bound toγ-actin.Silencing prg2 m RNA did not alter the expression ofγ-actin in Jurkat cells,but reduced F-actin polymerization and increased the ratio of G-actin/F-actin.Silencing prg2 m RNA also increased the expression of gelsolin,an enyme that cleaved F-actin,in Jurkat cells.PRG2 bound to gelsolin.The increased binding between gelsolin andγ-actin was observed in prg2-silienced Jurkat cells,indicating that PRG2 hindered the binding between gelsolin andγ-actin.The results of in vitro transwell experiments showed that the percentage and cell numbers of prg2-silienced Jurkat cells entertering to the lower chamber were significantly increased.The results of in vivo adoptive transfer experiments further showed that transferred prg2-silienced CD4⁺T cells preferredly migrated to the spleen in the recipient mice subjected to i BCG stimulation.Conclusion:PRG2 bound toγ-actin.PRG2 did not affect the expression ofγ-actin in Jurkat cells.PRG2inhibited F-actin polymerization and cytoskeleton remodeling via hindering gelsolin-induced actin depolymerization.Silencing prg2 promoted CD4⁺T cell to migrate and home to spleen.