Department of Pediatrics, Stanford University School of Medicine, Stanford, CA.
Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA; and.
Blood Adv. 2019 Sep 24;3(18):2751-2763. doi: 10.1182/bloodadvances.2019000537.
The del(5q) myelodysplastic syndrome (MDS) is a distinct subtype of MDS, associated with deletion of the ribosomal protein S14 () gene that results in macrocytic anemia. This study sought to identify novel targets for the treatment of patients with del(5q) MDS by performing an in vivo drug screen using an rps14-deficient zebrafish model. From this, we identified the secreted gelatinase matrix metalloproteinase 9 (MMP9). MMP9 inhibitors significantly improved the erythroid defect in rps14-deficient zebrafish. Similarly, treatment with MMP9 inhibitors increased the number of colony forming unit-erythroid colonies and the CD71 erythroid population from RPS14 knockdown human BMCD34 cells. Importantly, we found that MMP9 expression is upregulated in RPS14-deficient cells by monocyte chemoattractant protein 1. Double knockdown of MMP9 and RPS14 increased the CD71 population compared with RPS14 single knockdown, suggesting that increased expression of MMP9 contributes to the erythroid defect observed in RPS14-deficient cells. In addition, transforming growth factor β (TGF-β) signaling is activated in RPS14 knockdown cells, and treatment with SB431542, a TGF-β inhibitor, improved the defective erythroid development of RPS14-deficient models. We found that recombinant MMP9 treatment decreases the CD71 population through increased SMAD2/3 phosphorylation, suggesting that MMP9 directly activates TGF-β signaling in RPS14-deficient cells. Finally, we confirmed that MMP9 inhibitors reduce SMAD2/3 phosphorylation in RPS14-deficient cells to rescue the erythroid defect. In summary, these study results support a novel role for MMP9 in the pathogenesis of del(5q) MDS and the potential for the clinical use of MMP9 inhibitors in the treatment of patients with del(5q) MDS.
del(5q) 骨髓增生异常综合征（MDS）是一种独特的 MDS 亚型，与核糖体蛋白 S14（rps14）基因缺失有关，导致巨红细胞性贫血。本研究通过使用 rps14 缺陷斑马鱼模型进行体内药物筛选，旨在寻找治疗 del(5q) MDS 患者的新靶点。由此，我们鉴定到了一种分泌型明胶酶基质金属蛋白酶 9（MMP9）。MMP9 抑制剂可显著改善 rps14 缺陷斑马鱼的红细胞缺陷。同样，MMP9 抑制剂处理可增加 RPS14 敲低的人 BMCD34 细胞中的集落形成单位-红细胞集落数量和 CD71 阳性红细胞群体。重要的是，我们发现单核细胞趋化蛋白 1 可上调 rps14 缺陷细胞中的 MMP9 表达。与 RPS14 单敲低相比，MMP9 和 RPS14 的双重敲低增加了 CD71 阳性群体，表明 MMP9 的表达增加有助于观察到的 RPS14 缺陷细胞中的红细胞缺陷。此外，转化生长因子-β（TGF-β）信号在 RPS14 敲低细胞中被激活，并且 TGF-β 抑制剂 SB431542 处理可改善 RPS14 缺陷模型中缺陷的红细胞发育。我们发现重组 MMP9 处理通过增加 SMAD2/3 磷酸化来降低 CD71 阳性群体，表明 MMP9 可直接激活 RPS14 缺陷细胞中的 TGF-β 信号。最后，我们证实 MMP9 抑制剂可降低 RPS14 缺陷细胞中的 SMAD2/3 磷酸化以挽救红细胞缺陷。总之，这些研究结果支持 MMP9 在 del(5q) MDS 发病机制中的新作用以及 MMP9 抑制剂在治疗 del(5q) MDS 患者中的临床应用潜力。
