Cockayne syndrome (CS) is a developmental disorder with symptoms that are typical for the aging body, including subcutaneous fat loss, alopecia, and cataracts. Here, we show that in the cells of CS patients, RNA polymerase I transcription and the processing of the pre-rRNA are disturbed, leading to an accumulation of the 18S-E intermediate. The mature 18S rRNA level is reduced, and isolated ribosomes lack specific ribosomal proteins of the small 40S subunit. Ribosomal proteins are susceptible to unfolding and the CS cell proteome is heat-sensitive, indicating misfolded proteins and an error-prone translation process in CS cells. Pharmaceutical chaperones restored impaired cellular proliferation. Therefore, we provide evidence for severe protein synthesis malfunction, which together with a loss of proteostasis constitutes the underlying pathophysiology in CS.

Our objective was to evaluate the independent prognostic value of a novel MRI biomarker—objectively diagnosed diffuse white matter abnormality volume (DWMA; diffuse excessive high signal intensity)—for prediction of motor outcomes in very preterm infants. We prospectively enrolled a geographically-based cohort of very preterm infants without severe brain injury and born before 32 weeks gestational age. Structural brain MRI was obtained at term-equivalent age and DWMA volume was objectively quantified using a published validated algorithm. These results were compared with visually classified DWMA. We used multivariable linear regression to assess the value of DWMA volume, independent of known predictors, to predict motor development as assessed using the Bayley Scales of Infant & Toddler Development, Third Edition at 3 years of age. The mean (SD) gestational age of the cohort was 28.3 (2.4) weeks. In multivariable analyses, controlling for gestational age, sex, and abnormality on structural MRI, DWMA volume was an independent prognostic biomarker of Bayley Motor scores ($$\beta $$ β = −12.59 [95% CI −18.70, −6.48] R2 = 0.41). Conversely, visually classified DWMA was not predictive of motor development. In conclusion, objectively quantified DWMA is an independent prognostic biomarker of long-term motor development in very preterm infants and warrants further study.

The nucleolus organizes around the sites of transcription by RNA polymerase I (RNA Pol I). rDNA transcription by this enzyme is the key step of ribosome biogenesis and most of the assembly and maturation processes of the ribosome occur co-transcriptionally. Therefore, disturbances in rRNA transcription and processing translate to ribosomal malfunction. Nucleolar malfunction has recently been described in the classical progeria of childhood, Hutchinson–Gilford syndrome (HGPS), which is characterized by severe signs of premature aging, including atherosclerosis, alopecia, and osteoporosis. A deregulated ribosomal biogenesis with enlarged nucleoli is not only characteristic for HGPS patients, but it is also found in the fibroblasts of “normal” aging individuals. Cockayne syndrome (CS) is also characterized by signs of premature aging, including the loss of subcutaneous fat, alopecia, and cataracts. It has been shown that all genes in which a mutation causes CS, are involved in rDNA transcription by RNA Pol I. A disturbed ribosomal biogenesis affects mitochondria and translates into ribosomes with a reduced translational fidelity that causes endoplasmic reticulum (ER) stress and apoptosis. Therefore, it is speculated that disease-causing disturbances in the process of ribosomal biogenesis may be more common than hitherto anticipated.

TFIIH is a complex essential for transcription of protein-coding genes by RNA polymerase II, DNA repair of UV-lesions and transcription of rRNA by RNA polymerase I. Mutations in TFIIH cause the cancer prone DNA-repair disorder xeroderma pigmentosum (XP) and the developmental and premature aging disorders trichothiodystrophy (TTD) and Cockayne syndrome (CS). 50% of TTD cases are caused by TFIIH mutations. Using TFIIH mutant patient cells from TTD and XP subjects we can show that the stress-sensitivity of the proteome is reduced in TTD, but not in XP. Using three different methods to investigate the accuracy of protein synthesis by the ribosome, we demonstrate that translational fidelity of the ribosomes of TTD, but not XP cells, is decreased. The process of ribosomal synthesis and maturation is affected in TTD cells and can lead to instable ribosomes. Isolated ribosomes from TTD patients show an elevated error rate when challenged with oxidized mRNA, explaining the oxidative hypersensitivity of TTD cells. Treatment of TTD cells with N-acetyl cysteine normalized the increased translational error-rate and restored translational fidelity. Here we describe a pathomechanism that might be relevant for our understanding of impaired development and aging-associated neurodegeneration.

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Introduction: First pass effect (FPE) defined as TICI 3 recanalization or greater is an independent predictor of clinical outcome in patients who undergo mechanical thrombectomy (MT). The first pass effect may be impacted by device-related factors, thrombus composition, or collateral circulation flow dynamics. In this study, we aim to examine the impact of first pass effect on clinical outcomes in patients with MCA M1 occlusions. Methods: A retrospective analysis of all patients with MCA M1 occlusion who underwent successful mechanical thrombectomy (TICI 2b or greater) between 2014-2020 at two thrombectomy stroke centers was performed. Location of occlusion was recorded as proximal MCA (involvement of the lenticulostriate vessels) or distal. Patients were excluded if they were not successfully recanalized or if they had multifocal intracranial occlusions. Patient characteristics, time metrics, procedural data, and 90 day clinical outcomes were collected. The primary outcome of interest was first pass effect, defined as TICI 3 after a single pass. Results: A total of 261 patients achieved successful recanalization of MCA occlusions in our cohort, with 70 (26.8%) patients achieving a first pass effect. Baseline demographics, rates of IV-tPA administration, and time metrics were similar between the FPE and non-FPE group. Proportion of proximal MCA and distal MCA occlusions were similar between groups as well (38.2% vs. 25.7%; p=0.08). Rates of excellent clinical outcomes were significantly higher in the FPE group compared to the non-FPE group (46.3% vs. 29.9%; p=0.02). In a multivariate analysis, proximal MCA occlusion was a significant predictor of first pass effect. Conclusion: First pass effect in middle cerebral artery M1 occlusions is a significant predictor of an excellent clinical outcome. Patients with a proximal MCA M1 occlusion are more likely to achieve a first pass effect compared to patients with a distal MCA occlusion.

Our objective was to evaluate the independent prognostic value of a novel MRI biomarker − objectively diagnosed diffuse white matter abnormality volume (DWMA; diffuse excessive high signal intensity) − for prediction of motor outcomes in very preterm infants. We prospectively enrolled a geographically-based cohort of very preterm infants without severe brain injury and born before 32 weeks gestational age. Structural brain MRI was obtained at term-equivalent age and DWMA volume was objectively quantified using a published validated algorithm. These results were compared with visually classified DWMA. We used multivariable linear regression to assess the value of DWMA volume, independent of known predictors, to predict motor development as assessed using the Bayley Scales of Infant & Toddler Development, Third Edition at 3 years of age. The mean (SD) gestational age of the cohort was 28.3 (2.4) weeks. In multivariable analyses, controlling for gestational age, sex, and abnormality on structural MRI, DWMA volume was an independent prognostic biomarker of Bayley Motor scores (β= −12.59 [95% CI: −18.70, −6.48] R2=0.41). Conversely, visually classified DWMA was not predictive of motor development. In conclusion, objectively quantified DWMA is an independent prognostic biomarker of long-term motor development in very preterm infants and warrants further study.