QIMR Berghofer Medical Research Institute, Brisbane, Qld, 4029, Australia.
School of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, Brazil.
Sci Rep. 2019 Aug 27;9(1):12421. doi: 10.1038/s41598-019-48741-w.
SerpinB2 (plasminogen activator inhibitor type 2) has been called the "undecided serpin" with no clear consensus on its physiological role, although it is well described as an inhibitor of urokinase plasminogen activator (uPA). In macrophages, pro-inflammatory stimuli usually induce SerpinB2; however, expression is constitutive in Gata6+ large peritoneal macrophages (LPM). Interrogation of expression data from human macrophages treated with a range of stimuli using a new bioinformatics tool, CEMiTool, suggested that SerpinB2 is most tightly co- and counter-regulated with genes associated with cell movement. Using LPM from SerpinB2 and SerpinB2 (active site mutant) mice, we show that migration on Matrigel was faster than for their wild-type controls. Confocal microscopy illustrated that SerpinB2 and F-actin staining overlapped in focal adhesions and lamellipodia. Genes associated with migration and extracellular matrix interactions were also identified by RNA-Seq analysis of migrating RPM from wild-type and SerpinB2 mice. Subsequent gene set enrichment analyses (GSEA) suggested SerpinB2 counter-regulates many Gata6-regulated genes associated with migration. These data argue that the role of SerpinB2 in macrophages is inhibition of uPA-mediated plasmin generation during cell migration. GSEA also suggested that SerpinB2 expression (likely via ensuing modulation of uPA-receptor/integrin signaling) promotes the adoption of a resolution phase signature.
丝氨酸蛋白酶抑制剂 B2（纤溶酶原激活物抑制剂 2 型）又被称为“不确定的丝氨酸蛋白酶抑制剂”，其生理作用尚无明确共识，尽管它被很好地描述为尿激酶纤溶酶原激活物（uPA）的抑制剂。在巨噬细胞中，促炎刺激通常会诱导丝氨酸蛋白酶抑制剂 B2 的表达；然而，在 Gata6+大腹腔巨噬细胞（LPM）中，其表达是组成型的。使用一种新的生物信息学工具 CEMiTool 对用一系列刺激物处理的人巨噬细胞的表达数据进行分析，提示丝氨酸蛋白酶抑制剂 B2 与与细胞运动相关的基因密切协同和反向调节。利用丝氨酸蛋白酶抑制剂 B2 和丝氨酸蛋白酶抑制剂 B2（活性位点突变）小鼠的 LPM，我们发现其在 Matrigel 上的迁移速度快于其野生型对照。共聚焦显微镜表明，丝氨酸蛋白酶抑制剂 B2 和 F-肌动蛋白染色在焦点黏附处和片状伪足处重叠。通过对野生型和丝氨酸蛋白酶抑制剂 B2 小鼠的迁移 RPM 进行 RNA-Seq 分析，还鉴定出与迁移和细胞外基质相互作用相关的基因。随后的基因集富集分析（GSEA）表明，丝氨酸蛋白酶抑制剂 B2 反向调节许多与迁移相关的 Gata6 调节基因。这些数据表明，丝氨酸蛋白酶抑制剂 B2 在巨噬细胞中的作用是抑制 uPA 介导的纤溶酶生成，从而抑制细胞迁移。GSEA 还表明，丝氨酸蛋白酶抑制剂 B2 的表达（可能通过随后调节 uPA-受体/整合素信号传导）促进了分辨率阶段特征的出现。
