Department of Human Genetics, McGill University, Montreal, Quebec, Canada.
Department of Pediatrics, Research Institute of the McGill University Health Center, Montreal, Quebec, Canada.
J Cell Biochem. 2019 Mar;120(3):3243-3258. doi: 10.1002/jcb.27591. Epub 2018 Oct 26.
Zellweger spectrum disorder (ZSD) results from biallelic mutations in PEX genes required for peroxisome biogenesis. PEX1-G843D is a common hypomorphic allele in the patient population that is associated with milder disease. In prior work using a PEX1-G843D/null patient fibroblast line expressing a green fluorescent protein (GFP) reporter with a peroxisome-targeting signal (GFP-PTS1), we demonstrated that treatments with the chemical chaperone betaine and flavonoid acacetin diacetate recovered peroxisome functions. To identify more effective compounds for preclinical investigation, we evaluated 54 flavonoids using this cell-based phenotype assay. Diosmetin showed the most promising combination of potency and efficacy (EC50 2.5 µM). All active 5',7'-dihydroxyflavones showed greater average efficacy than their corresponding flavonols, whereas the corresponding flavanones, isoflavones, and chalcones tested were inactive. Additional treatment with the proteostasis regulator bortezomib increased the percentage of import-rescued cells over treatment with flavonoids alone. Cotreatments of diosmetin and betaine showed the most robust additive effects, as confirmed by three independent functional assays in primary PEX1-G843D patient cells, but neither agent was active alone or in combination in patient cells homozygous for the PEX1 c.2097_2098insT null allele. Moreover, diosmetin treatment increased PEX1, PEX6, and PEX5 protein levels in PEX1-G843D patient cells, but none of these proteins increased in PEX1 null cells. We propose that diosmetin acts as a pharmacological chaperone that improves the stability, conformation, and functions of PEX1/PEX6 exportomer complexes required for peroxisome assembly. We suggest that diosmetin, in clinical use for chronic venous disease, and related flavonoids warrant further preclinical investigation for the treatment of PEX1-G843D-associated ZSD.
泽尔韦格综合征（ZSD）是由于过氧化物酶体生物发生所需的双等位基因突变引起的。PEX1-G843D 是患者群体中常见的低功能等位基因，与更温和的疾病相关。在之前使用表达过氧化物酶体靶向信号（GFP-PTS1）的绿色荧光蛋白（GFP）报告基因的 PEX1-G843D/ 无效患者成纤维细胞系的工作中，我们证明了用化学伴侣甜菜碱和黄酮类化合物乙酰乙酸二乙酰处理可恢复过氧化物酶体功能。为了鉴定更有效的化合物进行临床前研究，我们使用这种基于细胞的表型测定法评估了 54 种黄酮类化合物。染料木素显示出最有希望的效力和疗效组合（EC50 为 2.5μM）。所有活性的 5',7'-二羟基黄酮的平均疗效均大于其相应的黄酮醇，而测试的相应黄烷酮、异黄酮和查耳酮均无活性。在用蛋白稳态调节剂硼替佐米进行额外治疗后，与单独用黄酮类化合物治疗相比，导入挽救细胞的百分比增加。染料木素和甜菜碱的联合治疗显示出最强大的相加作用，这在原发性 PEX1-G843D 患者细胞的三个独立功能测定中得到了证实，但在 PEX1 纯合子的患者细胞中，两种药物均无活性。c.2097_2098insT 无效等位基因。此外，染料木素处理可增加 PEX1-G843D 患者细胞中的 PEX1、PEX6 和 PEX5 蛋白水平，但 PEX1 无效细胞中的这些蛋白均未增加。我们提出，染料木素作为一种药理学伴侣，可改善过氧化物酶体组装所需的 PEX1/PEX6 输出物复合物的稳定性、构象和功能。我们建议，染料木素，在临床用于慢性静脉疾病，以及相关的类黄酮值得进一步的临床前研究，用于治疗 PEX1-G843D 相关的 ZSD。
