ウェルナー症候群

Microsatellite instability-high (MSI-H) colorectal cancer cells depend on the Werner syndrome helicase (WRN) to resolve cruciform DNA structures that arise from expanded TA-dinucleotide repeats. Loss of WRN induces replication stress and double-strand breaks (DSBs), a vulnerability that can be recapitulated by the selective WRN inhibitor HRO761 in MSI cancer cells. To uncover the mechanisms governing sensitivity to WRN inhibition, we conducted genome-wide CRISPR/Cas9 screens in colorectal cancer cell lines treated with or without HRO761. These screens identified SMARCAL1 as a key modulator of WRN dependency. Depletion of SMARCAL1 rendered cells resistant to WRN inhibition, and rescue of this effect required the ATPase/translocase activity of SMARCAL1. Mechanistically, SMARCAL1 antagonized WRN and supported cruciform DNA structures, thereby enhancing cellular reliance on WRN. In addition, the MRE11-RAD50-NBS1 (MRN) complex, rather than MUS81 or ERCC1/XPF, was the principal mediator of cruciform DNA processing following WRN inhibition. Acute disruption of the MRN complex conferred profound resistance to WRN inhibition, whereas ATM deficiency produced a more modest resistant phenotype. Further genetic and pharmacological epistasis analyses demonstrated that the MRN complex regulates WRN inhibitor sensitivity through both ATM-dependent signaling and MRE11 nuclease-dependent functions. Importantly, the key resistance mechanisms identified in this study were independently validated using a structurally distinct clinical-stage WRN inhibitor VVD-214. Collectively, these findings identify the SMARCAL1-MRN-ATM axis as a critical regulator of WRN dependency and provide mechanistic insight into resistance to WRN-targeted therapy.

BACKGROUND: Age-related DNA methylation changes are promising biomarkers to track the individual aging process. Particularly second-generation epigenetic clocks capture aspects of biological age more accurately, but the requirement of genome wide profiles hampers implementation into practice. We therefore aimed to develop a simplified, targeted approach based on individual age- and mortality-associated CpG sites measurable by digital PCR. RESULTS: We selected three CpG sites strongly associated with all-cause mortality in the Lothian Birth Cohorts and with chronological age in multiple publicly available repositories to establish the targeted age- and mortality-associated epigenetic clock (TaM clock). For comparison, we applied a previously published three-CpG signature selected solely for correlation with chronological age (TaC clock). These signatures were initially benchmarked using DNA methylation profiles from 20 frail and 20 non-frail participants of the ActiFE cohort. In fact, in this subset the TaM clock revealed significant association between the delta age and the frailty status based on a 32-item frailty index. Furthermore, the TaM clock outperformed the TaC clock at capturing a significant increase in epigenetic age in Down syndrome, Werner syndrome and HIV. We subsequently developed digital PCR assays to analyse 446 samples from the ActiFE cohort. One TaM clock site (cg20595453) showed significant association with both mortality and frailty. However, predictions generated by either targeted clock were not significantly associated with mortality and there was no clear relationship with frailty or age-related clinical parameters in this larger cohort. CONCLUSION: Our targeted signatures were not sensitive enough to reliably predict frailty or mortality in a relatively healthy study population, which seems to be a general challenge for epigenetic clocks. It may be necessary to include additional disease-associated target sites to support frailty analysis in personalized medicine.

BACKGROUND: Approximately one in four trauma patients admitted to the intensive care unit (ICU) develops an infection, resulting in 20% mortality. In trauma patients, it is difficult to distinguish the systemic inflammation due to injury from infection. Lack of a gold standard for diagnosing infection further complicates recognition and management of sepsis in this population. We developed and piloted an adjudication instrument to analyze infection status in critically injured trauma patients. METHODS: Adult trauma patients admitted to the ICU (January-October 2022) were included. Our multidisciplinary adjudication committee of six clinical experts collaboratively developed the case report form (CRF) and infection status form. The CRFs have structured clinical data, and the infection status form includes the likelihood of infection on a Likert scale, site, and type of infection. Two adjudicators were randomly assigned to independently review the CRF and complete the infection status form. If both provided concordant responses, consensus was achieved. If there was a discrepancy in responses, a third adjudicator was assigned to review. RESULTS: 40 patients underwent adjudication of infection status. Concordance between the two primary adjudicators was found in 82.5% (33/40). Of these, infection was identified in 18.2% (6/33). In all cases, adjudicators assessed a lung source of bacterial infection. Seven cases were reviewed by a third adjudicator, and infection was identified in 85.7% (6/7). CONCLUSIONS: In the absence of a gold standard for the diagnosis of infection in critically injured trauma patients, an adjudication process can be an effective way to standardize the assessment of a study event or endpoint. LEVEL OF EVIDENCE: Diagnostic tests or criteria; level II.

BACKGROUND: Structural variants (SVs) are a major class of genomic variation that profoundly influences human genetic diversity, evolution, and disease. Historically underappreciated due to detection challenges, SVs are now recognized as key drivers of both constitutional disorders and cancer. Understanding their origins and consequences is fundamental to modern genomics and clinical medicine. SUMMARY: SVs arise from the complex interplay between endogenous sources of DNA damage - such as reactive oxygen species, replication stress, and transcription-replication conflicts - and error-prone repair mechanisms including non-allelic homologous recombination, microhomology-mediated end joining, fork stalling and template switching, and break-induced replication. The formation and patterns of these variants are critically constrained by the three-dimensional architecture of the nucleus, particularly topologically associating domains, which determine the spatial proximity of potential translocation partners. Key insights into these processes are provided by genomic instability syndromes (e.g., Bloom syndrome, Fanconi anemia, Werner syndrome, Nijmegen breakage syndrome), where specific repair pathway defects result in characteristic SV signatures and clinical phenotypes. Similarly, cancer genomes serve as detailed molecular archives of repair failures, with distinct SV patterns now enabling prediction of underlying deficiencies such as BRCA loss. Thus, the pattern of SVs in a tumor genome can serve as a retrospective molecular archive of underlying repair failure, enabling 'signature-based' prediction of HR deficiency even when germline BRCA status is unknown. Emerging technologies, especially long-read sequencing, have revolutionized the field by achieving >95% sensitivity for SV detection and resolving previously intractable rearrangements. Furthermore, recent discoveries regarding biomolecular condensates in DNA repair (e.g., PARP1, MRNIP phase separation) reveal previously unrecognized regulatory layers governing repair pathway choice and SV formation. KEY MESSAGES: (i) SVs are generated by specific DNA lesions and error-prone repair processes, with their patterns shaped by nuclear architecture and three-dimensional genome organization. (ii) Genomic instability disorders and cancer genomes provide crucial mechanistic insights by linking specific repair pathway defects to characteristic SV signatures. (iii) Technological advances, particularly long-read sequencing, now enable comprehensive and sensitive detection of SVs, including those in complex repetitive regions. (iv) A unified framework for understanding SVs as products of DNA damage, cellular metabolism, and chromatin context has profound clinical implications for diagnostic reverse phenotyping, synthetic lethality strategies in oncology, and the development of targeted therapies.

OBJECTIVES: The aim of this study was to present three adult cases of obstructed hemivagina, and ipsilateral renal anomaly (OHVIRA) syndrome diagnosed in different gynecological centers in Poland. The clinical presentations, diagnostic imaging, surgical treatment, and outcomes were analyzed to highlight the diagnostic challenges and variability in clinical course. MATERIAL AND METHODS: This retrospective case series included three female patients aged 19,20 and 30 diagnosed in adulthood with OHVIRA syndrome. RESULTS: All three patients were diagnosed with uterus didelphys. Two had confirmed congenital right renal agenesis, while one had undergone nephrectomy in infancy. One patient presented with severe dysmenorrhea and purulent content in the right hemivagina, initially suspected to be hematocolpos. Another patient, with a history of adolescent hematocolpos, was diagnosed postpartum during assessment following cesarean section. The third case was identified incidentally during nephrological imaging. The patient had undergone the right nephrectomy in infancy. All patients underwent resection of the vaginal septum and drainage of hematocolpos. CONCLUSIONS: These cases show the variable clinical presentation of OHVIRA syndrome and emphasize the importance of a detailed history and imaging evaluation. Early diagnosis remains essential to prevent complications and provide treatment.