Hiramuki Yosuke, Hosokawa Miwa, Osawa Kayo, Shirakawa Taku, Watanabe Yasuhiro, Hanajima Ritsuko, Kugoh Hiroyuki, Awano Hiroyuki, Matsuo Masafumi, Kazuki Yasuhiro
Department of Chromosome Biomedical Engineering, School of Life Science, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori, 683‑8503, Japan.
Department of Chromosome Biomedical Engineering, Graduate School of Medical Science, Tottori University, 86 Nishi-cho, Yonago, Tottori, 683‑8503, Japan.
Sci Rep. 2025 Jan 13;15(1):1778. doi: 10.1038/s41598-025-85369-5.
Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder caused by mutations of the dystrophin gene, which spans 2.4 Mb on the X chromosome. Creatine kinase (CK) activity in blood and titin fragment levels in urine have been identified as biomarkers in DMD to monitor disease progression and evaluate therapeutic intervention. However, the difference in the sensitivity of these biomarkers in DMD remains unclear. Previously, we generated transchromosomic mice carrying the full-length human dystrophin gene on a human artificial chromosome (DYS-HAC1) vector. The human dystrophin derived from DYS-HAC1 improved pathological phenotypes observed in DMD-null mice, which lack the entire 2.4 Mb of the dystrophin gene. In this study, we compared the values of plasma CK activity and urine/plasma titin fragment levels in wild-type (WT), DYS-HAC1, DMD-null, and DYS-HAC1; DMD-null mice. Plasma CK activity and urine/plasma titin fragment levels in DMD-null mice were significantly higher than those in WT mice. Although plasma CK activity showed no significant difference between WT and DYS-HAC1; DMD-null mice, urine/plasma titin fragment levels in DYS-HAC1; DMD-null mice were higher than those in WT mice. Human dystrophin in DYS-HAC1; DMD-null mice drastically improved muscular dystrophy phenotypes seen in DMD-null mice; however, the proportion of myofibers with central nuclei in DYS-HAC1; DMD-null mice had a tendency to be slightly higher than that in WT mice. These results suggest that urine/plasma titin fragment levels could be a more sensitive biomarker than plasma CK activity.
杜兴氏肌营养不良症（DMD）是一种由肌营养不良蛋白基因突变引起的X连锁隐性疾病，该基因在X染色体上跨度为2.4兆碱基对。血液中的肌酸激酶（CK）活性和尿液中的肌联蛋白片段水平已被确定为DMD中的生物标志物，用于监测疾病进展和评估治疗干预。然而，这些生物标志物在DMD中的敏感性差异仍不清楚。此前，我们在人类人工染色体（DYS-HAC1）载体上培育出携带全长人类肌营养不良蛋白基因的转染色体小鼠。源自DYS-HAC1的人类肌营养不良蛋白改善了在缺乏整个2.4兆碱基对肌营养不良蛋白基因的DMD基因敲除小鼠中观察到的病理表型。在本研究中，我们比较了野生型（WT）、DYS-HAC1、DMD基因敲除和DYS-HAC1；DMD基因敲除小鼠的血浆CK活性值以及尿液/血浆肌联蛋白片段水平。DMD基因敲除小鼠的血浆CK活性和尿液/血浆肌联蛋白片段水平显著高于WT小鼠。虽然WT和DYS-HAC1；DMD基因敲除小鼠之间的血浆CK活性没有显著差异，但DYS-HAC1；DMD基因敲除小鼠的尿液/血浆肌联蛋白片段水平高于WT小鼠。DYS-HAC1；DMD基因敲除小鼠中的人类肌营养不良蛋白极大地改善了DMD基因敲除小鼠中所见的肌营养不良表型；然而，DYS-HAC1；DMD基因敲除小鼠中具有中央核的肌纤维比例有略高于WT小鼠的趋势。这些结果表明，尿液/血浆肌联蛋白片段水平可能是比血浆CK活性更敏感的生物标志物。
