Makaryan Vahagn, Kelley Merideth, Fletcher Breanna, Archibald Isabella, Poulsen Tanoya, Dale David
University of Washington, Department of Medicine, Seattle, Washington, USA.
J Cell Immunol. 2022;4(1):19-28. doi: 10.33696/immunology.4.129.
Heterozygous mutations in , the gene for neutrophil elastase, cause cyclic and congenital neutropenia through the programed cell death of neutrophil progenitors in the bone marrow. Granulocyte colony-stimulating factor is an effective therapy for these diseases, but alternative therapies are needed, especially for patients who do not respond well or are at high risk of developing myeloid malignancies. We developed an HL60 cell model for neutropenia and previously demonstrated that transient and regulated expression of mutant causes cell death by accelerated apoptosis. Knocking down the mutant gene or exposure to a potent inhibitor of neutrophil elastase rescued neutrophil development. Because of the great diversity in causative mutations, we generated stable HL60 clones expressing mutant P139L, C151Y and G214R and compared the effects of elastase inhibitor exposure to an knock-out line on cell development and function. ATRA induced differentiation demonstrated comparably impaired myeloid cell development for all three lines with upregulated expression of GRP78/BIP, an abnormality corrected by exposure of these cells to the elastase inhibitor MK-0339. The inhibitor and KO of mutant led to formation of neutrophils with comparable chemotactic and bactericidal capacities. We concluded that both strategies have great potential for the treatment of cyclic and congenital neutropenia. However, an orally absorbed, cell permeable inhibitor of neutrophil elastase, if proven safe and effective in a clinical trial, might be the better alternative to G-CSF or gene editing to treat neutropenia.
中性粒细胞弹性蛋白酶基因的杂合突变，通过骨髓中中性粒细胞祖细胞的程序性细胞死亡导致周期性和先天性中性粒细胞减少症。粒细胞集落刺激因子是治疗这些疾病的有效方法，但需要替代疗法，特别是对于那些反应不佳或有发生髓系恶性肿瘤高风险的患者。我们建立了一个用于中性粒细胞减少症的HL60细胞模型，并且之前证明了突变体的瞬时和调控表达通过加速凋亡导致细胞死亡。敲低突变基因或暴露于中性粒细胞弹性蛋白酶的有效抑制剂可挽救中性粒细胞的发育。由于致病突变的多样性很大，我们生成了表达突变体P139L、C151Y和G214R的稳定HL60克隆，并比较了弹性蛋白酶抑制剂暴露对敲除系细胞发育和功能的影响。全反式维甲酸诱导的分化表明，所有这三个系的髓样细胞发育均受到同等程度的损害，同时GRP78/BIP的表达上调，而将这些细胞暴露于弹性蛋白酶抑制剂MK-0339可纠正这一异常。突变体的抑制剂和敲除导致形成具有可比趋化和杀菌能力的中性粒细胞。我们得出结论，这两种策略在治疗周期性和先天性中性粒细胞减少症方面都有很大潜力。然而，如果一种口服吸收、细胞可渗透的中性粒细胞弹性蛋白酶抑制剂在临床试验中被证明安全有效，那么它可能是治疗中性粒细胞减少症比粒细胞集落刺激因子或基因编辑更好的选择。
