Yu-Xin Shao1, Zhao Lei1, Patricia G Wolf2, Yan Gao1, Yu-Ming Guo1, Bing-Kun Zhang3. 1. State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China; and. 2. Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL. 3. State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China; and bingkunzhang@126.com.
Abstract
Background: Zinc has been shown to improve intestinal barrier function against Salmonella enterica serovar Typhimurium (S. typhimurium) infection, but the mechanisms involved in this process remain undefined.Objective: We aimed to explore the roles of G protein-coupled receptor (GPR)39 and protein kinase Cζ (PKCζ) in the regulation by zinc of intestinal barrier function. Methods: A Transwell Caco-2 monolayer was pretreated with 0, 50, or 100 μM Zn and then incubated with S. typhimurium for 0-6 h. Afterward, cells silenced by the small interfering RNA for GPR39 or PKCζ were pretreated with 100 μM Zn and incubated with S. typhimurium for 3 h. Finally, transepithelial electrical resistance (TEER), permeability, tight junction (TJ) proteins, and signaling molecules GPR39 and PKCζ were measured. Results: Compared with controls, S. typhimurium decreased TEER by 62.3-96.2% at 4-6 h (P < 0.001), increased (P < 0.001) permeability at 6 h, and downregulated (P < 0.05) TJ protein zonula occludens (ZO)-1 and occludin by 104-123%, as well as Toll-like receptor 2 and PKCζ by 35.1% and 75.2%, respectively. Compared with S. typhimurium-challenged cells, 50 and 100 μM Zn improved TEER by 26.3-60.9% at 4-6 h (P < 0.001) and decreased (P < 0.001) permeability and bacterial invasion at 6 h. A total of 100 μM Zn increased ZO-1, occludin, GPR39, and PKCζ 0.72- to 1.34-fold (P < 0.05); however, 50 μM Zn did not affect ZO-1 or occludin (P > 0.1). Silencing GPR39 decreased (P < 0.05) zinc-activated PKCζ and blocked (P < 0.05) the promotion of zinc on epithelial integrity. Furthermore, silencing PKCζ counteracted the protective effect of zinc on epithelial integrity but did not inhibit GPR39 (P = 0.138). Conclusion: We demonstrated that zinc upregulates PKCζ by activating GPR39 to enhance the abundance of ZO-1, thereby improving epithelial integrity in S. typhimurium-infected Caco-2 cells.
Background: Zinc has been shown to improve intestinal barrier function against Salmonella enterica serovar Typhimurium (S. typhimurium) infection, but the mechanisms involved in this process remain undefined.Objective: We aimed to explore the roles of G protein-coupled receptor (GPR)39 and protein kinase Cζ (PKCζ) in the regulation by zinc of intestinal barrier function. Methods: A Transwell Caco-2 monolayer was pretreated with 0, 50, or 100 μM Zn and then incubated with S. typhimurium for 0-6 h. Afterward, cells silenced by the small interfering RNA for GPR39 or PKCζ were pretreated with 100 μM Zn and incubated with S. typhimurium for 3 h. Finally, transepithelial electrical resistance (TEER), permeability, tight junction (TJ) proteins, and signaling molecules GPR39 and PKCζ were measured. Results: Compared with controls, S. typhimurium decreased TEER by 62.3-96.2% at 4-6 h (P < 0.001), increased (P < 0.001) permeability at 6 h, and downregulated (P < 0.05) TJ protein zonula occludens (ZO)-1 and occludin by 104-123%, as well as Toll-like receptor 2 and PKCζ by 35.1% and 75.2%, respectively. Compared with S. typhimurium-challenged cells, 50 and 100 μM Zn improved TEER by 26.3-60.9% at 4-6 h (P < 0.001) and decreased (P < 0.001) permeability and bacterial invasion at 6 h. A total of 100 μM Zn increased ZO-1, occludin, GPR39, and PKCζ 0.72- to 1.34-fold (P < 0.05); however, 50 μM Zn did not affect ZO-1 or occludin (P > 0.1). Silencing GPR39 decreased (P < 0.05) zinc-activated PKCζ and blocked (P < 0.05) the promotion of zinc on epithelial integrity. Furthermore, silencing PKCζ counteracted the protective effect of zinc on epithelial integrity but did not inhibit GPR39 (P = 0.138). Conclusion: We demonstrated that zinc upregulates PKCζ by activating GPR39 to enhance the abundance of ZO-1, thereby improving epithelial integrity in S. typhimurium-infected Caco-2 cells.
Authors: Ann Katrin Sauer; Sigita Malijauskaite; Paula Meleady; Tobias M Boeckers; Kieran McGourty; Andreas M Grabrucker Journal: Cell Mol Life Sci Date: 2021-12-22 Impact factor: 9.261
Authors: Katherine M DiGuilio; Elizabeth Rybakovsky; Reza Abdavies; Romy Chamoun; Colleen A Flounders; Ariel Shepley-McTaggart; Ronald N Harty; James M Mullin Journal: Int J Mol Sci Date: 2022-03-10 Impact factor: 5.923