The Effects And Mechanism Of TGF-β1-Treated Bovine Mammary Epithelial-Derived Exosomes On Proliferation,Apoptosis And Migration Of Bovine Macrophages

Objective: Dairy cow mastitis is a common breast disease in dairy farming,which seriously affects the health and production performance of dairy cows,and even affects human health.The incidence of mastitis in dairy cows in China has been high,causing huge social and economic losses.Damage.Staphylococcus aureus is one of the main pathogens of mastitis in dairy cows.TGF-β1 is a multifunctional cytokine that plays an important role in regulating immune and cell proliferation.Our previous study found that cows with multiple mastitis had higher levels of TGF-β1,and TGF-β1 increased the susceptibility of dairy cow mammary epithelial cells to Staphylococcus aureus.However,under the action of TGF-β1,it is still unknown whether cow mammary epithelial cells affect the function of immune cells through intercellular communication.Therefore,this study hypothesized that under the action of TGF-β1,the exosomes derived from the mammary gland epithelial cells of cows may affect the function of bovine macrophages,aiming to explore that under the action of TGF-β1,the exosomes derived from the mammary gland epithelial cells of cows affect the giant cattle.The mechanism of function of phagocytes.Methods: In this study,we extracted normal bovine mammary epithelial(MAC-T)-derived exosomes(un-exo)and TGF-β1-treated bovine mammary epithelial-derived exosomes(t-exo)by ultracentrifugation and kit method,which was applied to bovine macrophages,and the effects of two exosomes on the proliferation and cell cycle of bovine macrophages were detected by MTT assay and cell flow assay.q RT-PCR and Western blot were used to identified the related protein signaling pathways.The effects of two exosomes on the apoptosis and migration of bovine macrophages were detected by MTT assay and cell flow assay.Finally,q RT-PCR was used to detect the effect of TGF-β1-treated bovine mammary epithelial-derived exosomes(t-exo)on the secretion of inflammatory cytokines in bovine macrophages.Results:(1)TGF-β1-treated bovine mammary epithelial-derived exosomes(t-exo)suppressed the cell cycle progression and inhibited the proliferation of bovine macrophages by activating the p38 MAPK signaling pathway.(2)Bovine mammary epithelial cell-derived exosomes can induce apoptosis of bovine macrophages independent of FADD signaling pathway.(3)Bovine mammary epithelial cell-derived exosomes can increase the migration ability of bovine macrophages.Under treatment of TGF-β1,the ability of bovine mammary epithelial-derived exosomes to promote the migration of bovine macrophages is down-regulated.(4)TGF-β1-treated bovine mammary epithelial-derived exosomes(t-exo)significantly up-regulated the secretion of bovine macrophage anti-inflammatory factor IL-10 and down-regulated the secretion of pro-inflammatory factor IL-12 in bovine macrophages.Conclusion: Under the action of TGF-β1,bovine mammary epithelial cell-derived exosomes can inhibit macrophage activity,which may be one of the reasons why cow herd is prone to mastitis due to higher TGF-β1 level,which is provided a new idea for the prevention and treatment of mastitis in dairy cows.Inhibition of p38 MAPK signaling pathway can be used as a target for restoring macrophage activity.Inhibition of exosome secretion of dairy cow mammary glands that TGF-β1 level is higher may be one of the methods formastitis prevention...