西澤 春紀

OBJECTIVE: Myotonic dystrophy type 1 (DM1) is an autosomal dominant neurodevelopmental disorder caused by CTG repeat expansion in the DMPK gene. Although the clinical classification of DM1 is determined by the CTG repeat length in DMPK, conventional sizing relies on Southern blotting, which is a suboptimal method in prenatal and PGD contexts as it requires large amounts of genomic DNA. We here evaluated the utility of nanopore long read sequencing (LRS) for DM1 diagnosis in these contexts. METHOD: LRS was performed with adaptive sampling or CRISPR/Cas9-mediated enrichment targeting DMPK. The use of whole genome amplified DNA (WGA-DNA) prepared with RepliG was also assessed. RESULTS: Adaptive sampling and Cas9-based LRS enabled detection of both the normal and expanded alleles. Further, LRS with CRISPR/Cas9-mediated enrichment improved efficiency and enabled accurate sizing of expanded CTG repeats exceeding 1000 units. In contrast, the use of whole genome amplified DNA prepared with RepliG did not permit reliable CTG repeat sizing, even when combined with adaptive sampling or CRISPR/Cas9. CONCLUSION: Nanopore sequencing can potentially replace Southern blotting for prenatal DM1 diagnosis, including repeat sizing. However, further improvement is needed for PGD using WGA-DNA.

OBJECTIVE: Uterine carcinosarcoma (UCS) is a rare and aggressive gynecological cancer with high recurrence rates and is associated with a poor prognosis. It is also characterized by a high frequency of copy number alterations (CNAs). This study aimed to determine which gene CNA contributes to progression-free survival (PFS) in patients with UCS to identify potential prognostic biomarkers and therapeutic targets. METHODS: DNA was extracted from formalin-fixed paraffin-embedded tissues of surgical specimens from 24 patients with UCS who were treated at Fujita Health University. Using the PleSSision-Rapid test, the mutation information of 145 cancer genes was analyzed. Oncoplot analysis was used to visualize gene mutation profiles. χ2 test, Kaplan-Meier analysis, and log-rank test were used for statistical analyses. RESULTS: The most frequently observed gene mutation was TP53 in the 24 UCS cases studied, while genes associated with the PI3K/AKT/mTOR signaling pathway, including PIK3CA, PTEN, PIK3R1, and PIK3R2 were commonly detected. In the χ2 test analysis, TP53 loss (p=0.029), PIK3CA amplification (p=0.034), and TSC2 loss (p=0.034) were significantly associated with recurrence. Kaplan-Meier survival analysis demonstrated a significant association between PIK3CA amplification and TSC2 loss with PFS, as determined by the log-rank test (p<0.05). CONCLUSION: In patients with UCS, TSC2 loss is linked to poorer PFS, highlighting its utility as a prognostic marker. The association between TSC2 loss and increased recurrence risk highlights the potential therapeutic advantage of targeting the mTOR pathway in TSC2-deficient tumors.

INTRODUCTION: Alternative RNA splicing adds diverse variations to gene function, and its abnormalities are occasionally associated with the etiology of disease. We examined this possibility in pre-eclampsia. METHODS: We performed transcriptome analysis of placentas from pre-eclamptic and normotensive pregnancies and screened for disease-specific aberrant splicing. RESULTS: We identified aberrant splicing at exon 14 in the ZC3H4 gene. This in-frame exon is generally skipped in placentas from normal pregnancies but often observed in those from pre-eclampsia patients. The level of exon inclusion did not correlate with disease severity, such as blood pressure or fetal weight, but showed an association with the decrease in placental weight. Significantly, placental blood flow resistance measured by Doppler ultrasound correlated with the level of ZC3H4 exon 14 inclusion, suggesting that this retention leads to the onset and/or symptoms of pre-eclampsia. ZC3H4 is known to act on transcriptional regulation via suppression of lncRNA expression. Moreover, the SOD1 gene, encoding superoxide dismutase that eliminates toxic free superoxide radicals, was identified in the downstream gene group for ZC3H4. Indeed, the expression of SOD1 was found in this current study to be decreased in the pre-eclamptic placenta in correlation with the levels of ZC3H4 exon 14 retention. DISCUSSION: Aberrant splicing of ZC3H4 gene may induce excessive oxidative stress in the placenta via the downregulation of downstream SOD1 expression thereby leading to the onset and development of pre-eclampsia.