Department of Pathology and Laboratory Medicine and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Rady Children's Institute for Genomic Medicine, Rady Children's Hospital, San Diego, California, USA.
J Inherit Metab Dis. 2021 Mar;44(2):492-501. doi: 10.1002/jimd.12354. Epub 2021 Jan 15.
Loss-of-function mutations in the deoxyguanosine kinase (DGUOK) gene result in a mitochondrial DNA (mtDNA) depletion syndrome. DGUOK plays an important role in converting deoxyribonucleosides to deoxyribonucleoside monophosphates via the salvage pathway for mtDNA synthesis. DGUOK deficiency manifests predominantly in the liver; the most common cause of death is liver failure within the first year of life and no therapeutic options are currently available. in vitro supplementation with deoxyguanosine or deoxyguanosine monophosphate (dGMP) were reported to rescue mtDNA depletion in DGUOK-deficient, patient-derived fibroblasts and myoblasts. CERC-913, a novel ProTide prodrug of dGMP, was designed to bypass defective DGUOK while improving permeability and stability relative to nucleoside monophosphates. To evaluate CERC-913 for its ability to rescue mtDNA depletion, we developed a primary hepatocyte culture model using liver tissue from DGUOK-deficient rats. DGUOK knockout rat hepatocyte cultures exhibit severely reduced mtDNA copy number (~10%) relative to wild type by qPCR and mtDNA content remains stable for up to 8 days in culture. CERC-913 increased mtDNA content in DGUOK-deficient hepatocytes up to 2.4-fold after 4 days of treatment in a dose-dependent fashion, which was significantly more effective than dGMP at similar concentrations. These early results suggest primary hepatocyte culture is a useful model for the study of mtDNA depletion syndromes and that CERC-913 treatment can improve mtDNA content in this model.
脱氧鸟苷激酶（DGUOK）基因的功能丧失突变导致线粒体 DNA（mtDNA）耗竭综合征。DGUOK 通过补救途径在 mtDNA 合成中将脱氧核苷转化为脱氧核苷一磷酸，从而发挥重要作用。DGUOK 缺乏主要表现为肝脏；最常见的死亡原因是生命的第一年发生肝衰竭，目前尚无治疗选择。据报道，体外补充脱氧鸟苷或脱氧鸟苷一磷酸（dGMP）可挽救 DGUOK 缺陷型患者来源的成纤维细胞和肌母细胞中的 mtDNA 耗竭。CERC-913 是一种新型 dGMP 的 ProTide 前药，旨在绕过有缺陷的 DGUOK，同时提高相对于核苷单磷酸的通透性和稳定性。为了评估 CERC-913 挽救 mtDNA 耗竭的能力，我们使用 DGUOK 缺陷型大鼠的肝组织开发了一种原代肝细胞培养模型。通过 qPCR，DGUOK 敲除大鼠肝细胞培养物的 mtDNA 拷贝数相对于野生型显着降低（~10%），并且在培养物中保持稳定长达 8 天。CERC-913 以剂量依赖性方式使 DGUOK 缺陷型肝细胞中的 mtDNA 含量在 4 天的治疗后增加了 2.4 倍，其效果明显优于类似浓度的 dGMP。这些早期结果表明原代肝细胞培养物是研究 mtDNA 耗竭综合征的有用模型，并且 CERC-913 治疗可以改善该模型中的 mtDNA 含量。
