Verachi Paola, Gobbo Francesca, Martelli Fabrizio, Martinelli Andrea, Sarli Giuseppe, Dunbar Andrew, Levine Ross L, Hoffman Ronald, Massucci Maria Teresa, Brandolini Laura, Giorgio Cristina, Allegretti Marcello, Migliaccio Anna Rita
Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum University, Bologna, Italy.
Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy.
Front Oncol. 2022 Mar 22;12:853484. doi: 10.3389/fonc.2022.853484. eCollection 2022.
A major role for human (h)CXCL8 (interleukin-8) in the pathobiology of myelofibrosis (MF) has been suggested by observations indicating that MF megakaryocytes express increased levels of hCXCL8 and that plasma levels of this cytokine in MF patients are predictive of poor patient outcomes. Here, we demonstrate that, in addition to high levels of TGF-β, the megakaryocytes from the bone marrow of the mouse model of myelofibrosis express high levels of murine (m)CXCL1, the murine equivalent of hCXCL8, and its receptors CXCR1 and CXCR2. Treatment with the CXCR1/R2 inhibitor, Reparixin in aged-matched mice demonstrated reductions in bone marrow and splenic fibrosis. Of note, the levels of fibrosis detected using two independent methods (Gomori and reticulin staining) were inversely correlated with plasma levels of Reparixin. Immunostaining of marrow sections indicated that the bone marrow from the Reparixin-treated group expressed lower levels of TGF-β1 than those expressed by the bone marrow from vehicle-treated mice while the levels of mCXCL1, and expression of CXCR1 and CXCR2, were similar to that of vehicle-treated mice. Moreover, immunofluorescence analyses performed on bone marrow sections from mice indicated that treatment with Reparixin induced expression of GATA1 while reducing expression of collagen III in megakaryocytes. These data suggest that in mice, Reparixin reduces fibrosis by reducing TGF-β1 and collagen III expression while increasing GATA1 in megakaryocytes. Our results provide a preclinical rationale for further evaluation of this drug alone and in combination with current JAK inhibitor therapy for the treatment of patients with myelofibrosis.
观察结果表明，骨髓纤维化（MF）患者的巨核细胞中人类（h）CXCL8（白细胞介素-8）水平升高，且该细胞因子在MF患者血浆中的水平可预测患者的不良预后，这提示hCXCL8在MF病理生物学中起主要作用。在此，我们证明，除了高水平的转化生长因子-β（TGF-β）外，骨髓纤维化小鼠模型骨髓中的巨核细胞还高表达小鼠（m）CXCL1（hCXCL8的小鼠等同物）及其受体CXCR1和CXCR2。在年龄匹配的小鼠中用CXCR1/R2抑制剂瑞帕霉素治疗，可使骨髓和脾脏纤维化减轻。值得注意的是，使用两种独立方法（戈莫里染色和网状纤维染色）检测到的纤维化水平与瑞帕霉素血浆水平呈负相关。骨髓切片免疫染色表明，瑞帕霉素治疗组骨髓中TGF-β1的表达水平低于载体治疗小鼠骨髓中的表达水平，而mCXCL1水平以及CXCR1和CXCR2的表达与载体治疗小鼠相似。此外，对小鼠骨髓切片进行的免疫荧光分析表明，瑞帕霉素治疗可诱导巨核细胞中GATA1的表达，同时降低胶原蛋白III的表达。这些数据表明，在小鼠中，瑞帕霉素通过降低TGF-β1和胶原蛋白III的表达，同时增加巨核细胞中GATA1的表达来减轻纤维化。我们的结果为进一步评估该药物单独使用以及与目前的JAK抑制剂联合治疗骨髓纤维化患者提供了临床前理论依据。
