B-cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Sci Signal. 2024 Aug 27;17(851):eade1119. doi: 10.1126/scisignal.ade1119.
Ligand-engaged chemokine receptors trigger nucleotide exchange in heterotrimeric Gα proteins, which stimulates cytoskeletal reorganization and cell polarity changes. To better understand the signaling events responsible for these cellular changes, we focused on early changes in F-actin dynamics after engagement of the chemokine receptor CXCR5 in murine splenic B cells. Within 10 seconds of exposure to the CXCR5 ligand CXCL13, three-dimensional lamellar-like pseudopods and F-actin-rich ridges appeared. The transient F-actin increase depended on Gα signaling, the PI3K/AKT pathway, ERK activation, phospholipase C activity, and Rac1/2 activation mediated by Dock2 (dedicator of cytokinesis 2). Immunoblot analyses identified the kinase WNK1 (with no lysine kinase 1) as a potential early AKT effector. Treating B cells with specific WNK inhibitors disrupted F-actin dynamics and impaired B cell polarity, motility, and chemotaxis. These changes were mimicked in a murine B cell line by CRISPR-Cas9 gene editing of , which also suggested that WNK1 contributed to B cell proliferation. Administration of a single dose of a WNK inhibitor transiently reduced B cell motility and polarity in the lymph nodes of live mice. These results indicate that WNK1 signaling maintains B cell responsiveness to CXCL13 and suggest that pharmacological inhibition of WNK1, which is involved in cancer progression and blood pressure regulation, may affect humoral immunity.
配体结合的趋化因子受体触发异三聚体 Gα 蛋白的核苷酸交换，从而刺激细胞骨架重排和细胞极性变化。为了更好地理解负责这些细胞变化的信号事件，我们专注于趋化因子受体 CXCR5 在小鼠脾 B 细胞中被激活后 F- 肌动蛋白动力学的早期变化。在暴露于 CXCR5 配体 CXCL13 后的 10 秒内，出现了三维片状伪足和富含 F- 肌动蛋白的脊。短暂的 F- 肌动蛋白增加依赖于 Gα 信号、PI3K/AKT 途径、ERK 激活、PLC 活性以及由 Dock2（胞质分裂的 dedicator 2）介导的 Rac1/2 激活。免疫印迹分析鉴定出激酶 WNK1（无赖氨酸激酶 1）作为潜在的早期 AKT 效应物。用特异性 WNK 抑制剂处理 B 细胞会破坏 F- 肌动蛋白动力学并损害 B 细胞极性、迁移和趋化性。CRISPR-Cas9 基因编辑在小鼠 B 细胞系中对 进行编辑，也模拟了这些变化，这也表明 WNK1 有助于 B 细胞增殖。单次给予 WNK 抑制剂可短暂降低活鼠淋巴结中 B 细胞的迁移和极性。这些结果表明 WNK1 信号维持 B 细胞对 CXCL13 的反应性，并表明涉及癌症进展和血压调节的 WNK1 的药理学抑制可能会影响体液免疫。
