Comprehensive genetic diagnosis of patients with Duchenne/Becker muscular dystrophy (DMD/BMD) and pathogenicity analysis of splice site variants in the DMD gene / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are caused by mutations in the DMD gene. The aim of this study is to identify pathogenic DMD variants in probands and reduce the risk of recurrence of the disease in affected families. Variations in 100 unrelated DMD/BMD patients were detected by multiplex ligation-dependent probe amplification (MLPA) and next-generation sequencing (NGS). Pathogenic variants in DMD were successfully identified in all cases, and 11 of them were novel. The most common mutations were intragenic deletions (69%), with two hotspots located in the 5' end (exons 2-19) and the central of the DMD gene (exons 45-55), while point mutations were observed in 22% patients. Further, c.1149+1G>A and c.1150-2A>G were confirmed by hybrid minigene splicing assay (HMSA). This two splice site mutations would lead to two aberrant DMD isoforms which give rise to severely truncated protein. Therefore, the clinical use of MLPA, NGS, and HMSA is an effective strategy to identify variants. Importantly, eight embryos were terminated pregnancies according to prenatal diagnosis and a healthy boy was successfully delivered by preimplantation genetic diagnosis (PGD). Early and accurate genetic diagnosis is essential for prenatal diagnosis/PGD to reduce the risk of recurrence of DMD in affected families.

Preliminary validation of high throughput screening methods for hepatotocity and genotoxicity in humanized HepaRG cells / 药物评价研究

Objective To detect the hepatotoxicity biomarkers using normal human hepatocyte (HepaRG) and high-content screening,and to combine the micronucleus test and single cell gel electrophoresis to estalish a rapid screening platform for in vitro cytotoxitity and genotoxicity.Methods The effects of rhubarb anthraquinones (AQs) on the reactive oxygen species (ROS),intracellular Ca2+ concentration and mitochondrial membrane potential (MMP) in HepaRG cells were studied using appropriate fluorescent probes Hoechst33342、DCFH-DA、Fluo4-AM、Mito Tracker Red CMX Ros and high-content screening methods,and the potential genotoxiciy triggered by AQs were analyzed using the high-content based cytokinesis block micronucleus test and high throughput comet assay.Results The intracellular ROS level of HepaRG cells was significantly elevated by a 24 h treatment with Emodin (25.0 μg/mL),aloe-emodin (25.0 μg/mL) or chrysophanol (50.0 μg/mL),which are dose-concentration dependent (P ＜ 0.05 and 0.01);the intracellular Ca2+ increased and mitochondrial damage were observed with the treatment of aloe-emodin (25.0 μg/mL) and rhein (50.0 μg/mL,P ＜ 0.05 and 0.01).Comparing to control group,Emodin (25.0 μg/mL) induced an increased micronucleus rate (1.59％ ± 0.68 ％,P ＜ 0.01) and significantly higher percentage tail DNA and Olive tail moment (respectively 10.155％ ± 2.17％ and 0.510 ± 0.06,P ＜ 0.05 and 0.01) after 24 h;while the chrysophanol increased the micronucleus rate to 1.29％ ± 0.54％ (P ＜ 0.01) after 72 h.Conelnsion The results on the cytotoxicities and genotoxicities of AQs are consistent with the literatures.In this study,a rapid screening model for both hepatotoxicity and genotoxicity was successfully established,which will help with the early screening during the drug development stage.