Disruption of Higher Order DNA Structures in Friedreich's Ataxia (GAA)n Repeats by PNA or LNA Targeting

Expansion of (GAA)n repeats in the first intron of the Frataxin gene is associated with reduced mRNA and protein levels and the development of Friedreich’s ataxia. (GAA)n expansions form non-canonical structures, including intramolecular triplex (H-DNA), and R-loops and are associated with epigenetic modifications. With the aim of interfering with higher order H-DNA (like) DNA structures within pathological (GAA)n expansions, we examined sequence-specific interaction of peptide nucleic acid (PNA) with (GAA)n repeats of different lengths (short: n=9, medium: n=75 or long: n=115) by chemical probing of triple helical and single stranded regions. We found that a triplex structure (H-DNA) forms at GAA repeats of different lengths; however, single stranded regions were not detected within the medium size pathological repeat, suggesting the presence of a more complex structure. Furthermore, (GAA)4-PNA binding of the repeat abolished all detectable triplex DNA structures, whereas (CTT)5-PNA did not. We present evidence that (GAA)4-PNA can invade the DNA at the repeat region by binding the DNA CTT strand, thereby preventing non-canonical-DNA formation, and that triplex invasion complexes by (CTT)5-PNA form at the GAA repeats. Locked nucleic acid (LNA) oligonucleotides also inhibited triplex formation at GAA repeat expansions, and atomic force microscopy analysis showed significant relaxation of plasmid morphology in the presence of GAA-LNA. Thus, by inhibiting disease related higher order DNA structures in the Frataxin gene, such PNA and LNA oligomers may have potential for discovery of drugs aiming at recovering Frataxin expression

Upon impact: the fate of adhering <i>Pseudomonas fluorescens</i> cells during Nanofiltration

Nanofiltration (NF) is a high-pressure membrane filtration process increasingly applied in drinking water treatment and water reuse processes. NF typically rejects divalent salts, organic matter, and micropollutants. However, the efficiency of NF is adversely affected by membrane biofouling, during which microorganisms adhere to the membrane and proliferate to create a biofilm. Here we show that adhered Pseudomonas fluorescens cells under high permeate flux conditions are met with high fluid shear and convective fluxes at the membrane-liquid interface, resulting in their structural damage and collapse. These results were confirmed by fluorescent staining, flow cytometry, and scanning electron microscopy. This present study offers a 'first-glimpse' of cell damage and death during the initial phases of bacterial adhesion to NF membranes and raises a key question about the role of this observed phenomena during early-stage biofilm formation under permeate flux and cross-flow conditions.European Research Council (ERC

Symptoms and quality of life at 1-year follow up of patients discharged after an acute COVID-19 episode.

Patients surviving COVID-19 have been described as being at risk of developing sequelae. We aimed to investigate and elicit persistent symptoms, emotional status and quality-of-life in patients discharged after an acute COVID-19 episode. Patient-reported outcome measures were collected during a telephone interview 30 days and 1 year after discharge. Patients' general health status was evaluated using questions based on their symptoms, emotional status was assessed using the items 9 to 12 of the HeartQoL questionnaire and quality of life was assessed at 1 year through the EQ-5D-5L. In patients with a history of cardiovascular disease, all 14 items of the HeartQoL questionnaire were completed to derive the HeartQoL global score. Among 687 patients who survived after being hospitalised for COVID-19 at the University Hospitals of Geneva between 26 February and 26 April 2020, 184 (27%) and 165 (24%), respectively, participated in the follow-up at 30 days and 1 year. Of these 184 participants, 62% were male, median age was 58 years and 21% had a past medical history of cardiovascular disease. At one month after discharge, 61% (113/184) of patients presented fatigue and 28% (52/184) dyspnoea. One year after discharge, the main complaints were persistent fatigue in 27% (45/165) of patients, neurological problems in 17% (28/165) and dyspnoea in 14% (23/165). Eight percent (14/184) of patients declared being significantly worried 1 month after discharge and 5% (9/184) feeling depressed. The number of patients reporting being significantly worried or depressed at 1 year was lower. Regarding the quality of life at 1 year, the median EQ-5D-5L visual analogue scale score was 80 (interquartile range 70-90). Approximately half of patients reported some symptoms 1 year after discharge following an acute episode of COVID-19. The predominant symptom was persistent fatigue both at 1-month and at 1-year follow-up. Emotional status and quality of life appeared satisfactory

Mortality and high risk of major adverse events in patients with COVID-19 and history of cardiovascular disease.

History of cardiovascular diseases (CVDs) may influence the prognosis of patients hospitalised for COVID-19. We investigated whether patients with previous CVD have increased risk of death and major adverse cardiovascular event (MACE) when hospitalised for COVID-19. We included 839 patients with COVID-19 hospitalised at the University Hospitals of Geneva. Demographic characteristics, medical history, laboratory values, ECG at admission and medications at admission were collected based on electronic medical records. The primary outcome was a composite of in-hospital mortality or MACE. Median age was 67 years, 453 (54%) were males and 277 (33%) had history of CVD. In total, 152 (18%) died and 687 (82%) were discharged, including 72 (9%) who survived a MACE. Patients with previous CVD were more at risk of composite outcomes 141/277 (51%) compared with those without CVD 83/562 (15%) (OR=6.0 (95% CI 4.3 to 8.4), p&lt;0.001). Multivariate analyses showed that history of CVD remained an independent risk factor of in-hospital death or MACE (OR=2.4; (95% CI 1.6 to 3.5)), as did age (OR for a 10-year increase=2.2 (95% CI 1.9 to 2.6)), male gender (OR=1.6 (95% CI 1.1 to 2.3)), chronic obstructive pulmonary disease (OR=2.1 (95% CI 1.0 to 4.2)) and lung infiltration associated with COVID-19 at CT scan (OR=1.9 (95% CI 1.2 to 3.0)). History of CVD (OR=2.9 (95% CI 1.7 to 5)), age (OR=2.5 (95% CI 2.0 to 3.2)), male gender (OR=1.6 (95% CI 0.98 to 2.6)) and elevated C reactive protein (CRP) levels on admission (OR for a 10 mg/L increase=1.1 (95% CI 1.1 to 1.2)) were independent risk factors for mortality. History of CVD is associated with higher in-hospital mortality and MACE in hospitalised patients with COVID-19. Other factors associated with higher in-hospital mortality are older age, male sex and elevated CRP on admission

Visualization and Interpretation of Eukaryotic DNA Replication Intermediates In Vivo by Electron Microscopy

The detailed understanding of the DNA replication process requires structural insight. The combination of psoralen cross-linking and electron microscopy has been extensively exploited to reveal the fine architecture of in vivo DNA replication intermediates. This approach proved instrumental to uncover the basic mechanisms of DNA duplication, as well as the perturbation of this process by various forms of replication stress. The replication structures are stabilized in vivo (by psoralen cross-linking) prior to extraction and enrichment procedures, allowing their visualization at the transmission electron micro- scope. This chapter outlines the procedures required to visualize and interpret in vivo replication interme- diates of genomic DNA, extracted from budding yeast, Xenopus egg extracts, or cultured mammalian cells