Coronavirus disease 2019: Facts and controversies

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DNA end resection by Dna2–Sgs1–RPA and its stimulation by Top3–Rmi1 and Mre11–Rad50–Xrs2

The repair of DNA double-strand breaks (DSBs) by homologous recombination requires processing of broken ends. For repair to start, the DSB must first be resected to generate a 3′-single-stranded DNA (ssDNA) overhang, which becomes a substrate for the DNA strand exchange protein, Rad51 (ref. 1). Genetic studies have implicated a multitude of proteins in the process, including helicases, nucleases and topoisomerases. Here we biochemically reconstitute elements of the resection process and reveal that it requires the nuclease Dna2, the RecQ-family helicase Sgs1 and the ssDNA-binding protein replication protein-A (RPA). We establish that Dna2, Sgs1 and RPA constitute a minimal protein complex capable of DNA resection in vitro. Sgs1 helicase unwinds the DNA to produce an intermediate that is digested by Dna2, and RPA stimulates DNA unwinding by Sgs1 in a species-specific manner. Interestingly, RPA is also required both to direct Dna2 nucleolytic activity to the 5′-terminated strand of the DNA break and to inhibit 3′ to 5′ degradation by Dna2, actions that generate and protect the 3′-ssDNA overhang, respectively. In addition to this core machinery, we establish that both the topoisomerase 3 (Top3) and Rmi1 complex and the Mre11–Rad50–Xrs2 complex (MRX) have important roles as stimulatory components. Stimulation of end resection by the Top3–Rmi1 heterodimer and the MRX proteins is by complex formation with Sgs1 (refs 5, 6), which unexpectedly stimulates DNA unwinding. We suggest that Top3–Rmi1 and MRX are important for recruitment of the Sgs1–Dna2 complex to DSBs. Our experiments provide a mechanistic framework for understanding the initial steps of recombinational DNA repair in eukaryotes

Regulatory control of DNA end resection by Sae2 phosphorylation

DNA end resection plays a critical function in DNA double-strand break repair pathway choice. Resected DNA ends are refractory to end-joining mechanisms and are instead channeled to homology-directed repair. Using biochemical, genetic, and imaging methods, we show that phosphorylation of Saccharomyces cerevisiae Sae2 controls its capacity to promote the Mre11-Rad50-Xrs2 (MRX) nuclease to initiate resection of blocked DNA ends by at least two distinct mechanisms. First, DNA damage and cell cycle-dependent phosphorylation leads to Sae2 tetramerization. Second, and independently, phosphorylation of the conserved C-terminal domain of Sae2 is a prerequisite for its physical interaction with Rad50, which is also crucial to promote the MRX endonuclease. The lack of this interaction explains the phenotype of rad50S mutants defective in the processing of Spo11-bound DNA ends during meiotic recombination. Our results define how phosphorylation controls the initiation of DNA end resection and therefore the choice between the key DNA double-strand break repair mechanisms

Age and gender influence on HIDRAdisk outcomes in adalimumab-treated hidradenitis suppurativa patients

Background Hidradenitis suppurativa (HS) is a chronic relapsing inflammatory skin disease characterized by a significant impairment of patients' quality of life (QoL). It has been recently found that clinical severity of HS does not correlate well with QoL. Therefore, it is important to enhance the evaluation of severity considering the disease burden on QoL. Recently, a new graphical tool able to better describe HS burden, the so-called HIDRAdisk, has been introduced. Objective To investigate the utility of HIDRAdisk in clinical practice before and after treatment and to analyse whether specific factors such as age and gender may influence the outcomes in patients with moderate-to-severe HS. Methods A single-centre retrospective study on 24 patients (13F/11M, mean age 38 +/- 15 years) with moderate-to-severe HS was performed. Clinical data (disease severity and quality of life) were collected at baseline and after 12 weeks of adalimumab. Results HIDRAdisk showed significantly better improvements in males (69.8 +/- 6.2-49.6 +/- 10.8) compared to females (80.7 +/- 6.0-72.3 +/- 6.7), P <0.001. A significant correlation was found in the total population between HS severity values measured through the modified Sartorius score (mSS) and QoL measured through HIDRAdisk. As regards the relationship between disease outcomes and age, a trend for better HIDRAdisk outcomes in younger patients (<40 years) compared to older ones was observed. Conclusions HIDRAdisk appears as a complete and informative tool which can easily measure the global burden of HS, guiding treatment choice and evaluating its efficacy

A 48-week update of a multicentre real-life experience of dupilumab in adult patients with moderate-to-severe atopic dermatitis

The long-term efficacy and safety of dupilumab has been demonstrated in clinical trials and only in few real-world studies. We conducted an extension analysis from a previous 16-week study on 109 adult patients affected by moderate-to-severe atopic dermatitis treated with dupilumab. Eczema-Area-and-Severity-Index (EASI), itch numerical-rating-score (itch-NRS), Dermatology-Life-Quality-Index (DLQI) scores, drug survival rate and occurrence of adverse events after 24 and 48 weeks of dupilumab treatment were retrospectively collected. Dupilumab demonstrated sustained improvement of disease severity, pruritus, and quality of life in our series with an increasing percentage of patients gaining EASI75 and EASI90 response during the study period. Few patients interrupted treatment resulting in a very high drug survival rate. We also confirmed the favorable safety profile of the drug with absence of serious adverse events and serious infections throughout the 48-week period. The prevalence of conjunctivitis was low and mainly occurred in the mid-term with resolution of the majority of cases at 48 weeks

Living with chronic spontaneous urticaria in italy. a narrative medicine project to improve the pathway of patient care

Chronic spontaneous urticaria (CSU) is perceived as a difficult to manage disease with negative impact on quality of life. The aim of this study was to highlight how to improve the care of people with CSU, using the methodology of narrative medicine. From June 2014 to March 2015, CSU-diagnosed patients and their physicians were asked to record their experiences of the condition in writing. Fourteen healthcare teams participated: 41% considered CSU as a challenge to overcome, while 22% experienced CSU as a big commitment. The number of professional involved was evaluated as insufficient in 11 hospitals. Seventy-five percent of the 190 Italian patients had visited 3 or more physicians before receiving a final diagnosis, with a perceived waste of time and resources. The therapeutic pathways were described as unsatisfactory in 83% of cases. As a result, anger and frustration were life-dominant emotions in 92% of patients. The critical points of the care pathway are related to organizational issues and lack of awareness

Venous thromboembolism in Cushing syndrome:results from an EuRRECa and Endo-ERN survey

Background: Patients with Cushing syndrome (CS) are at increased risk of venous thromboembolism (VTE). Objective: The aim was to evaluate the current management of new cases of CS with a focus on VTE and thromboprophylaxis. Design and methods: A survey was conducted within those that report in the electronic reporting tool (e-REC) of the European Registries for Rare Endocrine Conditions (EuRRECa) and the involved main thematic groups (MTG’s) of the European Reference Networks for Rare Endocrine Disorders (Endo-ERN) on new patients with CS from January 2021 to July 2022. Results: Of 222 patients (mean age 44 years, 165 females), 141 patients had Cushing disease (64%), 69 adrenal CS (31%), and 12 patients with ectopic CS (5.4%). The mean follow-up period post-CS diagnosis was 15 months (range 3–30). Cortisol-lowering medications were initiated in 38% of patients. One hundred fifty-four patients (69%) received thromboprophylaxis (including patients on chronic anticoagulant treatment), of which low-molecular-weight heparins were used in 96% of cases. VTE was reported in six patients (2.7%), of which one was fatal: two long before CS diagnosis, two between diagnosis and surgery, and two postoperatively. Three patients were using thromboprophylaxis at time of the VTE diagnosis. The incidence rate of VTE in patients after Cushing syndrome diagnosis in our study cohort was 14.6 (95% CI 5.5; 38.6) per 1000 person-years. Conclusion: Thirty percent of patients with CS did not receive preoperative thromboprophylaxis during their active disease stage, and half of the VTE cases even occurred during this stage despite thromboprophylaxis. Prospective trials to establish the optimal thromboprophylaxis strategy in CS patients are highly needed. Significance statement The incidence rate of venous thromboembolism in our study cohort was 14.6 (95% CI 5.5; 38.6) per 1000 person-years. Notably, this survey showed that there is great heterogeneity regarding time of initiation and duration of thromboprophylaxis in expert centers throughout Europe.</p

MutSβ exceeds MutSα in dinucleotide loop repair

The target substrates of DNA mismatch recognising factors MutSalpha (MSH2+MSH6) and MutSbeta (MSH2+MSH3) have already been widely researched. However, the extent of their functional redundancy and clinical substance remains unclear. Mismatch repair (MMR)-deficient tumours are strongly associated with microsatellite instability (MSI) and the degree and type of MSI seem to be dependent on the MMR gene affected, and is linked to its substrate specificities. Deficiency in MSH2 and MSH6 is associated with both mononucleotide and dinucleotide repeat instability. Although no pathogenic MSH3 mutations have been reported, its deficiency is also suggested to cause low dinucleotide repeat instability