Inhibition of Glycogen Synthase Kinase 3β Increases the Proportion and Suppressive Function of CD19+CD24hiCD27+ Breg Cells

Abstract

CD19+CD24hiCD27+ memory Breg cells exhibit decreased abundance in patients with chronic graft-versus-host disease (cGVHD) after liver transplantation and produce less IL-10 than those from patients without cGVHD and healthy donors. Due to the lack of Breg cells and the difficulty in expanding them in vitro, in mouse models and early human clinical trials, the adoptive transfer of Breg cells to autoimmune diseases is greatly restricted. Glycogen synthase kinase 3β (GSK-3β) is a multifunctional serine/threonine (ser/thr) protein kinase that can participate in B cell growth, metabolic activity, and proliferation. Phosphoprotein array analysis showed that p-GSK-3β-s9 was highly expressed in mBreg cells. Furthermore, here, we demonstrated that GSK-3β expression in mBreg cells is lower than that observed in B cells by flow cytometry. We found that the treatment of B cells with the specific GSK-3β inhibitor SB216763 can significantly increase the proportion and immunosuppressive function of mBreg cells in vitro. Nuclear factor of activated T cells (NFAT) is one of a pivotal regulator of gene expression in adaptive immune system. Here, we observed that inhibition of GSK-3β by SB216763 results in enhanced expression of NFATc1 in B cells, which is essential in regulating the ability of B cells to secrete IL-10. By constructing a xGVHD mouse model, we observed that SB216763-treated mBreg cells effectively prevent xenogeneic GVHD. Here we propose a novel strategy using SB216763 to inhibit GSK-3β and then enhance the proportion and immunosuppressive function of mBreg cells by increasing the expression of NFATc1. This approach may be used as a therapy to ameliorate GVHD and inflammatory diseases.

Immunosuppressive Mechanisms of Regulatory B Cells

“…In agreement with these results, the levels of IL-10-producing B cells are reduced in kidney transplant patients receiving inhibitors of mTOR ( 120 ). Another key regulator of the glycolytic pathway, the enzyme GSK3β, has been described as a repressor of IL-10 synthesis in B cells by enhancing the expression of NFATc1 ( 121 ). mTOR also enhances the activation of PPAR-γ, a key transcription factor for adipogenesis and metabolic reprogramming in activated T cells ( 122 ).…”

Metabolic Program of Regulatory B Lymphocytes and Influence in the Control of Malignant and Autoimmune Situations

“…Interestingly, GSK3β has been recently found highly expressed in CD24 hi CD27 + memory Breg cells. GSK3β specific inhibition increases their proportion and immunosuppressive function through enhanced expression of NFATc1 leading to IL-10 secretion ( 99 ). The proportions of the Breg subsets CD24 high CD38 high transitional cells and CD24 high CD27 int CD38 + plasmablasts were also increased but not those of TIM1 + B2 cells or CD25 high CD71 high CD73 - Br1 cells.…”

Recent Metabolic Advances for Preventing and Treating Acute and Chronic Graft Versus Host Disease

“…One isoform, GSK3β, has been shown to promote murine and human iTreg generation ( 129 ). Treatment of B cells with GSK3β inhibitor enhanced regulatory B cells (Bregs) differentiation and suppressive function ( 130 ). Chronic GVHD patients showed a reduced frequency of Bregs than allo-HSCT patients without GVHD ( 130 ).…”

“…Treatment of B cells with GSK3β inhibitor enhanced regulatory B cells (Bregs) differentiation and suppressive function ( 130 ). Chronic GVHD patients showed a reduced frequency of Bregs than allo-HSCT patients without GVHD ( 130 ). In a xenogeneic GVHD model, adoptive transfer of ex-vivo purified Bregs treated with the GSK3β inhibitor improved survival and reduced target organ damage in GVHD mice ( 130 ).…”

“…Chronic GVHD patients showed a reduced frequency of Bregs than allo-HSCT patients without GVHD ( 130 ). In a xenogeneic GVHD model, adoptive transfer of ex-vivo purified Bregs treated with the GSK3β inhibitor improved survival and reduced target organ damage in GVHD mice ( 130 ). Collectively, these studies lay a foundation for future research in exploiting the metabolic pathways to potentiate regulatory cell function in controlling and treating GVHD.…”