Of the many types of DNA damage, DNA double-strand breaks (DSBs) are probably the most deleterious. Mounting evidence points to an intricate relationship between DSBs and transcription. A cell system ...in which the impact on transcription can be investigated at precisely mapped genomic DSBs is essential to study this relationship. Here in a human cell line, we map genome-wide and at high resolution the DSBs induced by a restriction enzyme, and we characterize their impact on gene expression by four independent approaches by monitoring steady-state RNA levels, rates of RNA synthesis, transcription initiation and RNA polymerase II elongation. We consistently observe transcriptional repression in proximity to DSBs. Downregulation of transcription depends on ATM kinase activity and on the distance from the DSB. Our study couples for the first time, to the best of our knowledge, high-resolution mapping of DSBs with multilayered transcriptomics to dissect the events shaping gene expression after DSB induction at multiple endogenous sites.
The DNA damage response (DDR) preserves genomic integrity. Small non-coding RNAs termed DDRNAs are generated at DNA double-strand breaks (DSBs) and are critical for DDR activation. Here we show that ...active DDRNAs specifically localize to their damaged homologous genomic sites in a transcription-dependent manner. Following DNA damage, RNA polymerase II (RNAPII) binds to the MRE11-RAD50-NBS1 complex, is recruited to DSBs and synthesizes damage-induced long non-coding RNAs (dilncRNAs) from and towards DNA ends. DilncRNAs act both as DDRNA precursors and by recruiting DDRNAs through RNA-RNA pairing. Together, dilncRNAs and DDRNAs fuel DDR focus formation and associate with 53BP1. Accordingly, inhibition of RNAPII prevents DDRNA recruitment, DDR activation and DNA repair. Antisense oligonucleotides matching dilncRNAs and DDRNAs impair site-specific DDR focus formation and DNA repair. We propose that DDR signalling sites, in addition to sharing a common pool of proteins, individually host a unique set of site-specific RNAs necessary for DDR activation.
The fine modulation of transcriptional activity around DNA lesions is essential to carefully regulate the crosstalk between the activation of the DNA damage response, DNA repair and transcription, ...particularly when the lesion occurs next to actively transcribed genes. Recently, several studies have been carried out to investigate how DNA lesions impact on local transcription, but the emerging model remains incomplete. Transcription of genes around damaged DNA is actively downregulated by the DNA damage response through different mechanisms, which appear specific to the chromatin context, the type of DNA damage or its complexity. Intriguingly, emerging evidence also indicates that transcription of noncoding RNAs (ncRNAs) is induced at sites of DNA damage, producing small ncRNAs that are, in turn, required for a full DNA damage response activation. We discuss here these recent findings, highlighting the major unresolved questions in the field, and propose ways to reconcile these apparently contradictory observations.
DNA double‐strand breaks (DSBs) generation within actively transcribed regions elicits a complex transcriptional response in cis to the lesion that favors DSB repair. This causes both transcriptional repression of damaged genes and the biogenesis of DSB‐induced small noncoding RNAs. Here, we discuss the modulation of transcription at DSBs and its tight connection with the activation of the DNA damage response.
Background and purpose
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with limited treatment options. RNS60 is an immunomodulatory and neuroprotective investigational ...product that has shown efficacy in animal models of ALS and other neurodegenerative diseases. Its administration has been safe and well tolerated in ALS subjects in previous early phase trials.
Methods
This was a phase II, multicentre, randomized, double‐blind, placebo‐controlled, parallel‐group trial. Participants diagnosed with definite, probable or probable laboratory‐supported ALS were assigned to receive RNS60 or placebo administered for 24 weeks intravenously (375 ml) once a week and via nebulization (4 ml/day) on non‐infusion days, followed by an additional 24 weeks off‐treatment. The primary objective was to measure the effects of RNS60 treatment on selected biomarkers of inflammation and neurodegeneration in peripheral blood. Secondary objectives were to measure the effect of RNS60 on functional impairment (ALS Functional Rating Scale—Revised), a measure of self‐sufficiency, respiratory function (forced vital capacity, FVC), quality of life (ALS Assessment Questionnaire‐40, ALSAQ‐40) and survival. Tolerability and safety were assessed.
Results
Seventy‐four participants were assigned to RNS60 and 73 to placebo. Assessed biomarkers did not differ between arms. The mean rate of decline in FVC and the eating and drinking domain of ALSAQ‐40 was slower in the RNS60 arm (FVC, difference 0.41 per week, standard error 0.16, p = 0.0101; ALSAQ‐40, difference –0.19 per week, standard error 0.10, p = 0.0319). Adverse events were similar in the two arms. In a post hoc analysis, neurofilament light chain increased over time in bulbar onset placebo participants whilst remaining stable in those treated with RNS60.
Conclusions
The positive effects of RNS60 on selected measures of respiratory and bulbar function warrant further investigation.
•We estimated the accuracy of the 30 item-Geriatric Depression Scale (GDS-30) against the gold standard diagnosis of late-life depression performed with the Semi-Structured Clinical Diagnostic ...Interview for DSM-IV-TR Axis I Disorder.•In 843 older subjects from a large population-based study, at the optimal cut-off score (≥ 4), GDS-30 had 65.1% sensitivity and 68.4% specificity.•Using the standard cut-off score (≥ 10), the GDS-30 specificity reached 91.2%, while sensitivity dropped to 37.7%, with lower levels of screening accuracy.•The interaction between GDS-30 and educational level showed a significant effect, but not with age, gender, cognitive variables, apathy, somatic and psychiatric multimorbidity.•At the optimal cut-off score (≥ 7), the GDS-30 had better discrimination performances for the subjects with subjective memory complaints, with the educational level modulating diagnostic performance.
The prevalence of late-life depression (LLD) depends on the study sample, measurements, and diagnostic approaches. We estimated the 30 item-Geriatric Depression Scale (GDS-30) accuracy against the gold standard LLD diagnosis made with the Semi-structured Clinical Diagnostic Interview for DSM-IV-TR Axis I Disorders, focusing on the prevalence of a late-life major depressive disorder (MDD), in a population-based sample of 843 subjects aged>65 years, subdivided into three groups: normal cognition, subjective memory complaints, and mild cognitive impairment. At the optimal cut-off score (≥4), the GDS-30 showed 65.1% sensitivity and 68.4% specificity for LLD (63% and 66% for late-life MDD, respectively). Using the standard cut-off score (≥10), the GDS-30 specificity reached 91.2%, while sensitivity dropped to 37.7%, indicating a lower screening accuracy area under the curve(AUC):0.728, 95% confidence interval(CI):0.67–0–78. The GDS-30 performance was associated with educational level, but not with age, gender, cognition, apathy, and somatic/psychiatric multimorbidity. For subjective memory complaints subjects, at the optimal cut-off score (≥7), the GDS-30 showed better discrimination performances (AUC=0.792,95%CI:0.60–0.98), but again the educational level affected the diagnostic performance. In subjective memory complaints subjects, symptom-based scales like the GDS-30 may feature a better performance for diagnosing depression in older age, but the GDS-30 seems to require adjustment to the patient's educational level.
Objective
To assess whether physical activity is a risk factor for amyotrophic lateral sclerosis (ALS).
Methods
From February 2008 to April 2012, 652 patients with ALS from European population‐based ...registries (France, Ireland, Italy, United Kingdom, Serbia) and 1,166 population controls (matched for age, sex, and residency) were assessed. Upon direct interview, data were collected on occupation and history of sport and leisure activities, physical activity, and accidental injuries. Physical exercise was defined as having spent time doing activities that caused an individual to breath hard at least once per month and was coded as none, job‐related, and/or sport‐related. Sport‐related and work‐related physical exercise were quantified using metabolic equivalents (METs). Risks were calculated using conditional logistic regression models (adjusting for age, country, trauma, and job‐related physical activity) and expressed as odds ratios (ORs) and adjusted ORs (Adj ORs) with 95% confidence intervals (CIs).
Results
Overall physical activity was associated with reduced odds of having ALS (Adj OR = 0.65, 95% CI = 0.48–0.89) as were work‐related physical activity (Adj OR = 0.56, 95% CI = 0.36–0.87) and organized sports (Adj OR = 0.49, 95% CI = 0.32–0.75). An inverse correlation was observed between ALS, the duration of physical activity (p = 0.0041), and the cumulative MET scores, which became significant for the highest exposure (Adj OR = 0.34, 95% CI = 0.21–0.54). An inverse correlation between ALS and sport was found in women but not in men, and in subjects with repeated traumatic events.
Interpretation
Physical activity is not a risk factor for ALS and may eventually be protective against the disease. ANN NEUROL 2014;75:708–716
Highlights • Fluorescent light causes degeneration of dopamine neurons in substantia nigra. • Light at 710 nm does not cause degeneration of dopamine neurons in substantia nigra. • Light at 710 nm ...modulates the firing of dopamine neurons in substantia nigra. • Artificial light could be an epidemiological risk factor in Parkinson’s disease.
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