Impaired oxidative stress response characterizes HUWE1-promoted X-linked intellectual disability.

Mutations in the HECT, UBA and WWE domain-containing 1 (HUWE1) E3 ubiquitin ligase cause neurodevelopmental disorder X-linked intellectual disability (XLID). HUWE1 regulates essential processes such as genome integrity maintenance. Alterations in the genome integrity and accumulation of mutations have been tightly associated with the onset of neurodevelopmental disorders. Though HUWE1 mutations are clearly implicated in XLID and HUWE1 regulatory functions well explored, currently much is unknown about the molecular basis of HUWE1-promoted XLID. Here we showed that the HUWE1 expression is altered and mutation frequency increased in three different XLID individual (HUWE1 p.R2981H, p.R4187C and HUWE1 duplication) cell lines. The effect was most prominent in HUWE1 p.R4187C XLID cells and was accompanied with decreased DNA repair capacity and hypersensitivity to oxidative stress. Analysis of HUWE1 substrates revealed XLID-specific down-regulation of oxidative stress response DNA polymerase (Pol) λ caused by hyperactive HUWE1 p.R4187C. The subsequent restoration of Polλ levels counteracted the oxidative hypersensitivity. The observed alterations in the genome integrity maintenance may be particularly relevant in the cortical progenitor zones of human brain, as suggested by HUWE1 immunofluorescence analysis of cerebral organoids. These results provide evidence that impairments of the fundamental cellular processes, like genome integrity maintenance, characterize HUWE1-promoted XLID

Robust changes and sources of uncertainty in the projected hydrological regimes of Swiss catchments

Projections of discharge are key for future water resources management. These projections are subject to uncertainties, which are difficult to handle in the decision process on adaptation strategies. Uncertainties arise from different sources such as the emission scenarios, the climate models and their post-processing, the hydrological models and natural variability. Here we present a detailed and quantitative uncertainty assessment, based on recent climate scenarios for Switzerland (CH2011 data set) and covering catchments representative for mid-latitude alpine areas. This study relies on a particularly wide range of discharge projections resulting from the factorial combination of 3 emission scenarios, 10 to 20 regional climate models, 2 post-processing methods and 3 hydrological models of different complexity. This enabled us to decompose the uncertainty in the ensemble of projections using analyses of variance (ANOVA). We applied the same modeling setup to 6 catchments to assess the influence of catchment characteristics on the projected streamflow and focused on changes in the annual discharge cycle. The uncertainties captured by our setup originate mainly from the climate models and natural climate variability, but the choice of emission scenario plays a large role by the end of the century. The respective contribution of the different sources of uncertainty varied strongly among the catchments. The discharge changes were compared to the estimated natural decadal variability, which revealed that a climate change signal emerges even under the lowest emission scenario (RCP2.6) by the end of the century. Limiting emissions to RCP2.6 levels would nevertheless reduce the largest regime changes at the end of the 21st century by approximately a factor of two, in comparison to impacts projected for the high emission scenario SRES A2. We finally show that robust regime changes emerge despite the projection uncertainty. These changes are significant and are consistent across a wide range of scenarios and catchments. We propose their identification as a way to aid decision-making under uncertainty

Eosinophil Morphology Eosinophil granules and degranulation

Endogenous DNA damage is causally associated with the functional decline and transformation of stem cells that characterize aging. DNA lesions that have escaped DNA repair can induce replication stress and genomic breaks that induce senescence and apoptosis. It is not clear how stem and proliferating cells cope with accumulating endogenous DNA lesions and how these ultimately affect the physiology of cells and tissues. Here we have addressed these questions by investigating the hematopoietic system of mice deficient for Rev1, a core factor in DNA translesion synthesis (TLS), the postreplicative bypass of damaged nucleotides. Rev1 hematopoietic stem and progenitor cells displayed compromised proliferation, and replication stress that could be rescued with an antioxidant. The additional disruption of Xpc, essential for global-genome nucleotide excision repair (ggNER) of helix-distorting nucleotide lesions, resulted in the perinatal loss of hematopoietic stem cells, progressive loss of bone marrow, and fatal aplastic anemia between 3 and 4 months of age. This was associated with replication stress, genomic breaks, DNA damage signaling, senescence, and apoptosis in bone marrow. Surprisingly, the collapse of the Rev1Xpc bone marrow was associated with progressive mitochondrial dysfunction and consequent exacerbation of oxidative stress. These data reveal that, to protect its genomic and functional integrity, the hematopoietic system critically depends on the combined activities of repair and replication of helix-distorting oxidative nucleotide lesions by ggNER and Rev1-dependent TLS, respectively. The error-prone nature of TLS may provide mechanistic understanding of the accumulation of mutations in the hematopoietic system upon aging

Incidence of sexually transmitted infections and association with behavioural factors: Time-to-event analysis of a large pre-exposure prophylaxis (PrEP) cohort.

OBJECTIVES Our objective was to obtain long-term data on the incidence of sexually transmitted infections (STIs) and their association with behavioural factors after widespread pre-exposure prophylaxis (PrEP) implementation. METHODS This was a time-to-event analysis of a national PrEP cohort in Switzerland (SwissPrEPared study). Participants were people without HIV interested in taking PrEP with at least two STI screening visits. Primary outcomes were incidence rate of gonorrhoea, chlamydia, and syphilis. The association between behavioural factors and STI diagnosis was expressed using hazard ratios. We adjusted for testing frequency and calendar year. RESULTS This analysis included 3907 participants enrolled between April 2019 and April 2022, yielding 3815.7 person-years of follow-up for gonorrhoea (15 134 screenings), 3802.5 for chlamydia (15 141 screenings), and 3858.6 for syphilis (15 001 screenings). The median age was 39 years (interquartile range [IQR] 32-47), 93.8% (n = 3664) identified as men who have sex with men (MSM). The incidence was 22.8 (95% confidence interval [CI] 21.3-24.4) per 100 person-years for gonorrhoea, 26.3 (95% CI 24.7-28.0) for chlamydia, and 4.4 (95% CI 3.8-5.1) for syphilis. Yearly incidence rates decreased between 2019 (all bacterial STIs: 81.6; 95% CI 59.1-109.9) and 2022 (all bacterial STIs: 49.8; 95% CI 44.6-55.3). Participants reporting chemsex substance use were at higher risk of incident STIs, as were those reporting multiple sexual partners. Younger age was associated with a higher risk of gonorrhoea and chlamydia. CONCLUSIONS Incidence rates of bacterial STIs decreased over time. Young MSM, those with multiple partners, and those using chemsex substances were at increased risk of STIs

Incidence of sexually transmitted infections and association with behavioural factors: Time-to-event analysis of a large pre-exposure prophylaxis (PrEP) cohort

OBJECTIVES: Our objective was to obtain long-term data on the incidence of sexually transmitted infections (STIs) and their association with behavioural factors after widespread pre-exposure prophylaxis (PrEP) implementation. METHODS: This was a time-to-event analysis of a national PrEP cohort in Switzerland (SwissPrEPared study). Participants were people without HIV interested in taking PrEP with at least two STI screening visits. Primary outcomes were incidence rate of gonorrhoea, chlamydia, and syphilis. The association between behavioural factors and STI diagnosis was expressed using hazard ratios. We adjusted for testing frequency and calendar year. RESULTS: This analysis included 3907 participants enrolled between April 2019 and April 2022, yielding 3815.7 person-years of follow-up for gonorrhoea (15 134 screenings), 3802.5 for chlamydia (15 141 screenings), and 3858.6 for syphilis (15 001 screenings). The median age was 39 years (interquartile range [IQR] 32-47), 93.8% (n = 3664) identified as men who have sex with men (MSM). The incidence was 22.8 (95% confidence interval [CI] 21.3-24.4) per 100 person-years for gonorrhoea, 26.3 (95% CI 24.7-28.0) for chlamydia, and 4.4 (95% CI 3.8-5.1) for syphilis. Yearly incidence rates decreased between 2019 (all bacterial STIs: 81.6; 95% CI 59.1-109.9) and 2022 (all bacterial STIs: 49.8; 95% CI 44.6-55.3). Participants reporting chemsex substance use were at higher risk of incident STIs, as were those reporting multiple sexual partners. Younger age was associated with a higher risk of gonorrhoea and chlamydia. CONCLUSIONS: Incidence rates of bacterial STIs decreased over time. Young MSM, those with multiple partners, and those using chemsex substances were at increased risk of STIs

Base Excision Repair in Physiology and Pathology of the Central Nervous System

Relatively low levels of antioxidant enzymes and high oxygen metabolism result in formation of numerous oxidized DNA lesions in the tissues of the central nervous system. Accumulation of damage in the DNA, due to continuous genotoxic stress, has been linked to both aging and the development of various neurodegenerative disorders. Different DNA repair pathways have evolved to successfully act on damaged DNA and prevent genomic instability. The predominant and essential DNA repair pathway for the removal of small DNA base lesions is base excision repair (BER). In this review we will discuss the current knowledge on the involvement of BER proteins in the maintenance of genetic stability in different brain regions and how changes in the levels of these proteins contribute to aging and the onset of neurodegenerative disorders

Involvement of the AAA ATPase p97/VCP in DNA metabolism

Cell cycle checkpoints are essential in eukaryotic cells to maintain the integrity of the genome despite constant exposure to endogenous and exogenous stressors attacking the DNA molecule. The aim of this study was to characterize the influence of the AAA ATPase p97/VCP on the functional efficiency of the G2/M cell cycle checkpoint. Since the specificity of p97/VCP is given by interaction with distinct adaptors, the Npl4 subunit of the heterodimeric main adaptor Ufd1/Npl4 was also part of the project. Additionally, smc5 and mms21 were investigated in this context as they are supposed to be potential substrates of p97/VCP. For this purpose, the proteins of choice were down regulated in U2OS cells by using siRNA. Mitotic indices of control cells and cells exposed to ionizing radiation were determined to monitor the activity of the checkpoint. This was performed in cells randomly distributed throughout the cell cycle as well as in synchronized cells. The results indicated that the G2/M checkpoint is neither significantly affected by p97/VCP nor by Npl4, smc5 or mms21. However, these results gave reason to investigate the role of p97/VCP, Npl4 and mms21 in DNA replication. Surprisingly, FACS cell cycle analysis then revealed a delayed onset of the S phase in cells depleted for p97/VCP and Npl4. Kontrollpunkte im Zellzyklus eukaryotischer Zellen sind unentbehrlich um die Integrität des Genoms, trotz fortwährenden Attacken endogener und exogener Stressoren auf die DNA, sicher zu stellen. Das Ziel dieser Arbeit war es, den Einfluss der AAA ATPase p97/VCP auf die Funktionstüchtigkeit des G2/M Kontrollpunktes zu charakterisieren. Da die Spezifität von p97/VCP auf der Interaktion mit bestimmten Adaptoren basiert, war Npl4, eine Untereinheit des heterodimeren Hauptadaptors Ufd1/Npl4, ebenfalls Teil des Projektes. Zusätzlich wurde der Einfluss von smc5 und mms21, zwei potentielle Substrate von p97/VCP, genauer untersucht. Zu diesem Zweck wurden U2OS Zellen mit siRNA behandelt, um das gewünschte Protein vorübergehend auszuschalten. Zur darauf folgenden Überwachung der Aktivität des Kontrollpunktes wurde der mitotische Index bestimmt. Dies wurde sowohl in Kontrollzellen durchgeführt, wie auch in Zellen, welche mit 3 Gy respektive 10 Gy bestrahlt wurden. Die erhaltenen Resultate zeigten, dass in unsynchronisierten, wie auch in synchronisierten Zellen der G2/M Kontrollpunkt durch p97/VCP, Npl4, smc5 und mms21 nicht wesentlich beeinflusst wird. Jedoch haben dieselben Resultate Anlass dazu gegeben, p97/VCP, Npl4 und mms21 im Zusammenhang mit der DNA Replikation zu untersuchen. Wenn Zellen mit siRNA gegen p97/VCP und Npl4 behandelt wurden, zeigte die Zellzyklusanalyse mittels FACS einen verzögerten Eintritt in die S Phase

Medical end-of-life decisions in the oldest old in Switzerland

AIMS OF THE STUDY: To analyse medical end-of-life decision making among the oldest old (80+ years) in Switzerland, focusing not only on treatments withheld or withdrawn but also on those continued until death. METHODS: This was a retrospective follow-up study of deaths registered in Switzerland between August 2013 and January 2014 using a standardised questionnaire completed by the attending physician. All individuals aged 65 years and older who did not die suddenly and completely unexpectedly, and who had met the responding physician prior to death were included (n = 2842). We examined three age groups: 65–79, 80–89, and 90+ years. Logistic regression analysis was used to identify age-related differences, controlled for place of death and sociodemographic characteristics. RESULTS: In 83.8% of the study population at least one medical end-of-life decision was made, and for 39.4% the use of a potentially life-sustaining treatment was documented. Alleviation of pain and other symptoms with a possible life-shortening effect was performed with 29% higher odds among the 90+-year-olds (odds ratio [OR] 1.29, 95% confidence interval [CI] 1.01–1.66) than in the youngest age group. Withholding or withdrawing potentially life-sustaining treatment with or without the explicit intention to hasten death did not differ with age. However, when the frequency of withholding a potentially life-sustaining treatment was compared with the frequency of using this treatment (either continued until death or withdrawn later on), the former was more common in old age (80–89 years), and particularly in very old age (90+ years) for most of the treatments studied. This applied especially for ventilator therapy (80–89 years: OR 2.83, 95% CI 1.82–4.41; 90+ years: OR 6.17, 95% CI 2.89–13.17, compared with 65–79 years), artificial nutrition (ORs 2.33, 95% CI 1.46–3.71 and 4.44, 95% CI 2.28–8.65, respectively), and antibiotics (ORs 1.53, 95% CI 1.11–2.09 and 1.57, 95% CI 1.05–2.35, respectively). Age had no independent impact on artificial hydration. CONCLUSIONS: The use of some potentially life-sustaining treatments decreased with older age and, in relation, the relative frequency of withholding such treatments increased. There may be various reasons for this finding: less benefit of a particular treatment in older patients for instance due to comorbidities, higher burden of treatment, and finally a tacit consensus of physicians and patients that death is nearing

Medical end-of-life decisions in Switzerland 2001 and 2013: Who is involved and how does the decision-making capacity of the patient impact?

QUESTIONS UNDER STUDY: In Switzerland, the prevalence of medical end-of-life practices had been assessed on a population level only once - in 2001 - until in 2013/14 an identical study was conducted. We aimed to compare the results of the 2001 and 2013 studies with a special focus on shared decision-making and patients' decision-making capacity. METHODS: Our study encompassed a 21.3% sample of deaths among residents of the German-speaking part of Switzerland aged 1 year or older. From 4998 mailed questionnaires, 3173 (63.5%) were returned. All data were weighted to adjust for age- and sex-specific differences in response rates. RESULTS: Cases with at least one reported end-of-life practice significantly increased from 74.5% (2001) to 82.3% (2013) of all deaths eligible for an end-of-life decision (p <0.001). In 51.2% there was a combination of at least two different end-of-life decisions in one case. In relation to discussion with patients or relatives and otherwise expressed preferences of the patient, 76.5% (74.5-78.4%) of all cases with reported medical end-of-life practice in 2013 (2001: 74.4%) relied on shared decision-making, varying from 79.8% (76.5-82.7%) among not at all capable patients to 87.8% (85.0-90.2%) among fully capable patients. In contrast to a generally increasing trend, the prevalence of end-of-life practices discussed with fully capable patients decreased from 79.0% (75.3-82.3%) in 2001 to 73.2% (69.6-76.0%) in 2013 (p = 0.037). CONCLUSIONS: Despite a generally high incidence of end-of-life practices in Switzerland, there remains potential for further improvement in shared decision-making. Efforts to motivate physicians to involve patients and relatives may be a win-win situation