Which clinical factors delay proper treatment in panic disorder? A cross-sectional multicentric study

AIM

The aim of the present study was to identify clinical and socio-demographic factors associated with duration of untreated illness (DUI) in patients affected by panic disorder (PD).

METHODS

Data were collected from patients' medical records (N = 157) of two mental health services respectively located in Milan and in Monza (Italy). Correlation analyses and analysis of variance (ANOVAs) were run to analyse the relation between DUI and quantitative/qualitative variables respectively. Statistically significant variables in uni- variate analyses were then inserted in a linear multivariable regression model (backward procedure).

RESULTS

Mean DUI was 27.33 (±50.56) months. Patients with an earlier age at onset (r = -0.270; p < .01), a longer duration of illness (r = 0.483; p < .01) and who received a lifetime psychotherapy (F = 6.86; p = .01) had a longer DUI. The final global model showed that a longer DUI was associated with pre-onset poly-substance misuse (p = .05) and a longer duration of illness (p < .01).

CONCLUSION

The results of our study showed that a longer DUI was predicted by clinical factors such as the presence of a pre-onset poly-substance use disorder and that delayed proper treatment can lead to a chronicization of PD, as indicated by a longer duration of illness. Further studies are needed to in-depth investigate the role of DUI in influencing the course and outcome of anxiety disorders, including PD.

SARS-CoV-2 hampers dopamine production in iPSC-derived dopaminergic neurons

An increasing number of patients experiences prolonged symptoms, whose profile and timeline remain uncertain, a condition that has been defined as post COVID. The majority of recovered hospitalized patients manifests at least one persistent symptom even sixty days after the first clinical manifestation's onset. Particularly, in light of the COVID-19-related symptomatology, it has been hypothesized that SARS-CoV-2 might affect the dopamine pathway. However, no scientific evidence has been produced so far. To this end, human iPSC-derived dopaminergic neurons were infected with EU, Delta and Omicron SARS-CoV-2 variants. The infection with EU and Delta variants, but not with Omicron, results in a reduced intracellular content and extracellular release of dopamine. Indeed, the tyrosine hydroxylase was found to be significantly upregulated at the mRNA level, while being greatly reduced at the protein level. The major downstream synthetic enzyme DOPA-decarboxylase and the dopamine transporter were significantly downregulated both at the mRNA and protein level. Notably, in vitro SARS-CoV-2 infection was also associated with an altered MAP2 and TAU expression and with an increased presence of neuronal stress markers. These preliminary observations suggest that the dopamine metabolism and production are affected by SARS-CoV-2, partially explaining some of the neurological symptoms manifested.

The PP2A phosphatase counteracts the function of the 9-1-1 axis in checkpoint activation

DNA damage elicits a checkpoint response depending on the Mec1/ATR kinase, which detects the presence of single-stranded DNA and activates the effector kinase Rad53/CHK2. In Saccharomyces cerevisiae, one of the signaling circuits leading to Rad53 activation involves the evolutionarily conserved 9-1-1 complex, which acts as a platform for the binding of Dpb11 and Rad9 (referred to as the 9-1-1 axis) to generate a protein complex that allows Mec1 activation. By examining the effects of both loss-of-function and hypermorphic mutations, here, we show that the Cdc55 and Tpd3 subunits of the PP2A phosphatase counteract activation of the 9-1-1 axis. The lack of this inhibitory function results in DNA-damage sensitivity, sustained checkpoint-mediated cell-cycle arrest, and impaired resection of DNA double-strand breaks. This PP2A anti-checkpoint role depends on the capacity of Cdc55 to interact with Ddc1 and to counteract Ddc1-Dpb11 complex formation by preventing Dpb11 recognition of Ddc1 phosphorylated on Thr602.

Cognitive dysfunction and psychopathology: a cohort study of adults with intellectual developmental disorder

BACKGROUND

Cognitive impairment of intellectual developmental disorders (IDD) is determined by several different combinations of specific cognitive alterations. People with IDD present a rate of mental health problems that is up to 4 times higher than that of the general population. Despite this, the relationship between specific cognitive dysfunctions and co-occurring mental disorders has not been adequately studied. The aim of the present paper is to investigate the association between specific cognitive dysfunctions and specific psychiatric symptoms and syndromes in people with IDD.

METHODS

One hundred and twenty adults with mild to moderate IDD living in residential facilities underwent a clinical and instrumental assessment for specific cognitive and psychopathological features.

RESULTS

Participants with IDD and ASD have significantly lower scores compared to those without respect to who has not the diagnosis on the Processing Speed Index (PSI) and Perceptual Reasoning Index (PRI) on the WAIS-IV and higher time scores on the TMT A. Moreover, there is a significant association between years of hospitalisation and TMT B and TMT B A time scores; the longer a participant with IDD was hospitalised, the worse their performance on the TMT. Although not statistically significant, many psychopathological clusters showed substantial cognitive profiles.

CONCLUSIONS

Although further research is needed, neuropsychological and IQ tests scores seem to be differently associated to various psychopathological conditions co-occurring with IDD, and with ASD especially. Cognitive assessment seems to support diagnosis and treatment of psychopathological co-occurrences in persons with IDD, also in consideration of indirect implications including a better knowledge of the patient's characteristics beyond IQ deficit.

The Chromatin Landscape around DNA Double-Strand Breaks in Yeast and Its Influence on DNA Repair Pathway Choice

DNA double-strand breaks (DSBs) are harmful DNA lesions, which elicit catastrophic consequences for genome stability if not properly repaired. DSBs can be repaired by either non-homologous end joining (NHEJ) or homologous recombination (HR). The choice between these two pathways depends on which proteins bind to the DSB ends and how their action is regulated. NHEJ initiates with the binding of the Ku complex to the DNA ends, while HR is initiated by the nucleolytic degradation of the 5'-ended DNA strands, which requires several DNA nucleases/helicases and generates single-stranded DNA overhangs. DSB repair occurs within a precisely organized chromatin environment, where the DNA is wrapped around histone octamers to form the nucleosomes. Nucleosomes impose a barrier to the DNA end processing and repair machinery. Chromatin organization around a DSB is modified to allow proper DSB repair either by the removal of entire nucleosomes, thanks to the action of chromatin remodeling factors, or by post-translational modifications of histones, thus increasing chromatin flexibility and the accessibility of repair enzymes to the DNA. Here, we review histone post-translational modifications occurring around a DSB in the yeast Saccharomyces cerevisiae and their role in DSB repair, with particular attention to DSB repair pathway choice.

Comparing the COVID-19-related PTSD symptoms between psychiatric patients and healthy subjects: an observational retrospective study from Northern Italy

COVID-19 pandemic had a great impact on mental health, both in the general population and psychiatric patients. Little is known about the difference between these two populations in perceiving the pandemic as a traumatic event. The aim of the study was to compare psychiatric patients and healthy controls (HC) in terms of change over time of post-traumatic (PTSD) symptoms. Demographic and clinical variables were collected. Impact of Event Scale Revised (IES-R) scores were registered at T1 as lockdown period (March-April 2020) and T2 as restarting (May-June 2020). Descriptive analyses and linear regression models were performed. A total of 166 outpatients and 57 HC were recruited. Time (F = 15.76; p < 0.001) and diagnosis (F = 4.94; p < 0.001) had a significant effect on the change of IES-R scores, which resulted T1 > T2 (p < 0.001), except for subjects affected by Obsessive-Compulsive Disorder (OCD). Overall, IES-R scores were < in patients than in HC (p = 0.02), particularly in the schizophrenia (SKZ) subgroup (p < 0.001). IES-R scores of subjects with personality disorders (PDs) resulted to be > HC, although not statistically significant. The lockdown period was perceived as more traumatic than the reopening phase by both groups, with the exception of OCD patients, probably because of the clinical worsening associated with the urge of control against risks of contamination. Overall, HC reported more PTSD symptoms than psychiatric patients did, particularly SKZ ones. PD patients, in contrast, may be more vulnerable to PTSD symptoms probably as a result of poor coping skills. Together with OCD patients, subjects with PDs may need closer monitoring during the different phases of the pandemic. Trial Registration: ClinicalTrials.gov Identifier: NCT04694482.

Prevalence and features of delirium in older patients admitted to rehabilitation facilities: a multicenter study

BACKGROUND

Delirium is thought to be common across various settings of care; however, still little research has been conducted in rehabilitation.

AIM

We investigated the prevalence of delirium, its features and motor subtypes in older patients admitted to rehabilitation facilities during the three editions of the "Delirium Day project".

METHODS

We conducted a cross-sectional study in which 1237 older patients (age ≥ 65 years old) admitted to 50 Italian rehabilitation wards during the three editions of the "Delirium Day project" (2015 to 2017) were included. Delirium was evaluated through the 4AT and its motor subtype with the Delirium Motor Subtype Scale.

RESULTS

Delirium was detected in 226 patients (18%), and the most recurrent motor subtype was mixed (37%), followed by hypoactive (26%), hyperactive (21%) and non-motor one (16%). In a multivariate Poisson regression model with robust variance, factors associated with delirium were: disability in basic (PR 1.48, 95%CI: 1.17-1.9, p value 0.001) and instrumental activities of daily living (PR 1.58, 95%CI: 1.08-2.32, p value 0.018), dementia (PR 2.10, 95%CI: 1.62-2.73, p value < 0.0001), typical antipsychotics (PR 1.47, 95%CI: 1.10-1.95, p value 0.008), antidepressants other than selective serotonin reuptake inhibitors (PR 1.3, 95%CI: 1.02-1.66, p value 0.035), and physical restraints (PR 2.37, 95%CI: 1.68-3.36, p value < 0.0001).

CONCLUSION

This multicenter study reports that 2 out 10 patients admitted to rehabilitations had delirium on the index day. Mixed delirium was the most prevalent subtype. Delirium was associated with unmodifiable (dementia, disability) and modifiable (physical restraints, medications) factors. Identification of these factors should prompt specific interventions aimed to prevent or mitigate delirium.

The association between low skeletal muscle mass and delirium: results from the nationwide multi-centre Italian Delirium Day 2017

Introduction

Delirium and sarcopenia are common, although underdiagnosed, geriatric syndromes. Several pathological mechanisms can link delirium and low skeletal muscle mass, but few studies have investigated their association. We aimed to investigate (1) the association between delirium and low skeletal muscle mass and (2) the possible role of calf circumference mass in finding cases with delirium.

Methods

The analyses were conducted employing the cross-sectional “Delirium Day” initiative, on patient 65 years and older admitted to acute hospital medical wards, emergency departments, rehabilitation wards, nursing homes and hospices in Italy in 2017. Delirium was diagnosed as a 4 + score at the 4-AT scale. Low skeletal muscle mass was operationally defined as calf circumference ≤ 34 cm in males and ≤ 33 cm in females. Logistic regression models were used to investigate the association between low skeletal muscle mass and delirium. The discriminative ability of calf circumference was evaluated using non-parametric ROC analyses.

Results

A sample of 1675 patients was analyzed. In total, 73.6% of participants had low skeletal muscle mass and 24.1% exhibited delirium. Low skeletal muscle mass and delirium showed an independent association (OR: 1.50; 95% CI 1.09–2.08). In the subsample of patients without a diagnosis of dementia, the inclusion of calf circumference in a model based on age and sex significantly improved its discriminative accuracy [area under the curve (AUC) 0.69 vs 0.57, p < 0.001].

Discussion and conclusion

Low muscle mass is independently associated with delirium. In patients without a previous diagnosis of dementia, calf circumference may help to better identify those who develop delirium.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40520-021-01950-8.

Evaluation of procoagulant imbalance in Cushing's syndrome after short- and long-term remission of disease

OBJECTIVE

Patients with Cushing's syndrome (CS) are at high risk of venous thromboembolism related to a hypercoagulability due to procoagulant imbalance. However, whether these alterations are reversible after disease remission is still unclear. The endogenous thrombin potential (ETP) measured with and without the addition of thrombomodulin provides a global representation of coagulation and previous data confirmed hypercoagulable profile in patients with active hypercortisolism. Aim of this study was to assess the short- and long-term modification of ETP in patients with CS after disease remission.

DESIGN AND METHODS

Nineteen patients with CS for whom surgical remission was achieved, were prospectively evaluated for clinical characteristics, cortisol secretion profile and ETP at different time points: (i) before surgical intervention; (ii) after 6 months and (iii) 5 years from the time of persistent remission. Nineteen healthy subjects matched for age and gender were also evaluated as control group.

RESULTS

Before surgery, patients showed higher ETP-ratio (with/without thrombomodulin) than controls (0.62 ± 0.09-vs-0.56 ± 0.09, p = 0.034). No significant correlation between ETP-ratio and cortisol secretion was found. 6 months after remission, ETP-ratio was still significantly increased compared to controls (0.64 ± 0.09-vs-0.56 ± 0.09, p = 0.01), but was similar to baseline (0.64 ± 0.09-vs-0.62 ± 0.09, p = 0.87). At 5 years, ETP-ratio showed a significant decrease (0.55 ± 0.14-vs-0.62 ± 0.09, p = 0.02) and was comparable to controls (0.55 ± 0.14-vs-0.56 ± 0.09, p = 0.7).

CONCLUSIONS

Plasma hypercoagulability detected in patients with active hypercortisolism persists at short-term evaluation and seems to be completely reversible after long-term remission of disease. These data, as part of a whole evaluation of thrombotic risk, can contribute to make appropriate therapeutic choice in these patients.

Dpb4 promotes resection of DNA double-strand breaks and checkpoint activation by acting in two different protein complexes

Budding yeast Dpb4 (POLE3/CHRAC17 in mammals) is a highly conserved histone fold protein that is shared by two protein complexes: the chromatin remodeler ISW2/hCHRAC and the DNA polymerase ε (Pol ε) holoenzyme. In Saccharomyces cerevisiae, Dpb4 forms histone-like dimers with Dls1 in the ISW2 complex and with Dpb3 in the Pol ε complex. Here, we show that Dpb4 plays two functions in sensing and processing DNA double-strand breaks (DSBs). Dpb4 promotes histone removal and DSB resection by interacting with Dls1 to facilitate the association of the Isw2 ATPase to DSBs. Furthermore, it promotes checkpoint activation by interacting with Dpb3 to facilitate the association of the checkpoint protein Rad9 to DSBs. Persistence of both Isw2 and Rad9 at DSBs is enhanced by the A62S mutation that is located in the Dpb4 histone fold domain and increases Dpb4 association at DSBs. Thus, Dpb4 exerts two distinct functions at DSBs depending on its interactors.

The histone folding protein Dpb4 forms histone-like dimers within the ISW2 complex and the Pol ε complex in S. cerevisiae. Here the authors reveal insights into two distinct functions that Dpb4 exerts at DSBs depending on its interactors.

The regulation of the DNA damage response at telomeres: focus on kinases

The natural ends of linear chromosomes resemble those of accidental double-strand breaks (DSBs). DSBs induce a multifaceted cellular response that promotes the repair of lesions and slows down cell cycle progression. This response is not elicited at chromosome ends, which are organized in nucleoprotein structures called telomeres. Besides counteracting DSB response through specialized telomere-binding proteins, telomeres also prevent chromosome shortening. Despite of the different fate of telomeres and DSBs, many proteins involved in the DSB response also localize at telomeres and participate in telomere homeostasis. In particular, the DSB master regulators Tel1/ATM and Mec1/ATR contribute to telomere length maintenance and arrest cell cycle progression when chromosome ends shorten, thus promoting a tumor-suppressive process known as replicative senescence. During senescence, the actions of both these apical kinases and telomere-binding proteins allow checkpoint activation while bulk DNA repair activities at telomeres are still inhibited. Checkpoint-mediated cell cycle arrest also prevents further telomere erosion and deprotection that would favor chromosome rearrangements, which are known to increase cancer-associated genome instability. This review summarizes recent insights into functions and regulation of Tel1/ATM and Mec1/ATR at telomeres both in the presence and in the absence of telomerase, focusing mainly on discoveries in budding yeast.

Lung Allograft Dysfunction in a COVID-19 Transplanted Patient is Associated with a Peculiar Immunopathological Phenotype

Purpose

Lung transplantation (LT) after severe SARS-CoV-2 infection is emerging as a life-saving medical procedure for selected patients who experience acute respiratory distress syndrome (ARDS). We present the first immunopathological evaluation of a lung allograft rejection in a patient who underwent LT because of irreversible ARDS related to COVID-19.

Methods

Two male patients with irreversible ARDS caused by COVID-19 underwent bilateral LT at our Institution. A surveillance transbronchial biopsy (TBB) was performed 2 months after LT in the first patient (Pt#1), while the second patient (Pt#2) died because of allograft rejection at day 62 post LT and explanted lungs were retrieved. CT imaging of the lungs was performed three days before death. Morphological examination was performed by H&E, whereas the immunophenotyping was performed by immunohistochemistry.

Results

Imaging and morphological examination of Pt#2 lungs indicated the presence of a graft dysfunction with features of a restrictive, widespread usual interstitial pneumonia-like syndrome (Fig. 1A, B). The immunophenotyping showed that B-lymphocytes (CD20-positive) were nearly absent, CD8-T-cells were not particularly expanded (mean positive cells within the lung stroma=13.8%; Fig. 1C), and the CD4/CD8 ratio was not decreased (Fig. 1D). The T-regs (Foxp3-positive) were 6% of the overall population (Fig. 1E). Analysis of the immune checkpoint molecules PD1, Tigit, CTLA4 and PDL1 showed that the expression of PD-L1 alone was highly increased in vases and in alveolar cells of rejected lungs, whereas it was nearly undetectable in the TBB from Pt#1 (Fig. 1F, G).

Conclusion

PDL1 expression in vases was previously documented as a sign of indirect ARDS. Together with our preliminary data, we can hypothesize that PDL1 may play a role in tissue effacement and graft failure, possibly indicating poor allograft prognosis.

SARS-CoV-2 viability on different surfaces after gaseous ozone treatment: a preliminary evaluation

COVID-19 is a global health threat with a huge number of confirmed cases and deaths all over the world. Human-to-human transmission via respiratory droplets and contact with aerosol-infected surfaces are the major routes of virus spread. Because SARS-CoV-2 can remain in the air and on surfaces from several hours to several days, disinfection of frequently touched surfaces and critical rooms, in addition to observing individual hygiene tips, is required to reduce the virus spreading. Here we report on an investigation into the use of gaseous ozone as a potentially effective sanitizing method against the new coronavirus.

Resection of a DNA Double-Strand Break by Alkaline Gel Electrophoresis and Southern Blotting

Generation of 3' single-stranded DNA (ssDNA) at the ends of a double-strand break (DSB) is essential to initiate repair by homology-directed mechanisms. Here we describe a Southern blot-based method to visualize the generation of ssDNA at the ends of site-specific DSBs generated in the Saccharomyces cerevisiae genome.

All-Optical Two-Color Terahertz Emission from Quasi-2D Nonlinear Surfaces

Two-color terahertz (THz) generation is a field-matter process combining an optical pulse and its second harmonic. Its application in condensed matter is challenged by the lack of phase matching among multiple interacting fields. Here, we demonstrate phase-matching-free two-color THz conversion in condensed matter by introducing a highly resonant absorptive system. The generation is driven by a third-order nonlinear interaction localized at the surface of a narrow-band-gap semiconductor, and depends directly on the relative phase between the two colors. We show how to isolate the third-order effect among other competitive THz-emitting surface mechanisms, exposing the general features of the two-color process.

Intergenerational transmission of antisocial personality disorder: Maternal role and its declination

Antisocial personality disorder is a well-established disease which features space from cruelty to lack of empathy and remorse. Its etiology has been deeply analyzed both for genetic and environmental implications. The role of family context has been underlined throughout the whole psychopathology as an explanation to the etiological conflict between nature and nurture. Even if this conflict seems to be apparently solved, it is still possible to ponder about family implications in terms of causes and consequences. In the antisocial field, maternal role may offer interesting and surprising food for thought. Even if it is commonly believed an intergenerational transmission of aberrant behaviors, particularly in terms of learning behaviors and lack of empathy assimilation, it exists a side part of maternal pathological expression that may play a role in the intergenerational transmission and it is extremely difficult to be detected. Female declination of this disorder may be expressed also through somatic implications and complaints, leading to the hypothesis of a self-reflection of the lack of consideration for other's needs, which is distinctive. It is of extreme importance, particularly in terms of prevention, to consider and identify these connotations of the disorder to be able to try to interrupt the cycle of transmission through generations.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Negative Refraction in Time-Varying Strongly Coupled Plasmonic-Antenna-Epsilon-Near-Zero Systems

Time-varying metasurfaces are emerging as a powerful instrument for the dynamical control of the electromagnetic properties of a propagating wave. Here we demonstrate an efficient time-varying metasurface based on plasmonic nano-antennas strongly coupled to an epsilon-near-zero (ENZ) deeply subwavelength film. The plasmonic resonance of the metal resonators strongly interacts with the optical ENZ modes, providing a Rabi level spitting of ∼30%. Optical pumping at frequency ω induces a nonlinear polarization oscillating at 2ω responsible for an efficient generation of a phase conjugate and a negative refracted beam with a conversion efficiency that is more than 4 orders of magnitude greater compared to the bare ENZ film. The introduction of a strongly coupled plasmonic system therefore provides a simple and effective route towards the implementation of ENZ physics at the nanoscale.

Prescribing Patterns of Psychotropic Drugs and Risk of Violent Behavior: A Prospective, Multicenter Study in Italy

BACKGROUND

This prospective cohort study aimed at evaluating patterns of polypharmacy and aggressive and violent behavior during a 1-year follow-up in patients with severe mental disorders.

METHODS

A total of 340 patients (125 inpatients from residential facilities and 215 outpatients) were evaluated at baseline with the Structured Clinical Interview for DSM-IV Axis I and II, Brief Psychiatric Rating Scale, Specific Levels of Functioning scale, Brown-Goodwin Lifetime History of Aggression, Buss-Durkee Hostility Inventory, Barratt Impulsiveness Scale, and State-Trait Anger Expression Inventory-2. Aggressive behavior was rated every 15 days with the Modified Overt Aggression Scale and treatment compliance with the Medication Adherence Rating Scale.

RESULTS

The whole sample was prescribed mainly antipsychotics with high levels of polypharmacy. Clozapine prescription and higher compliance were associated with lower levels of aggressive and violent behavior. Patients with a history of violence who took clozapine were prescribed the highest number of drugs. The patterns of cumulative Modified Overt Aggression Scale mean scores of patients taking clozapine (n = 46), other antipsychotics (n = 257), and no antipsychotics (n = 37) were significantly different (P = .001). Patients taking clozapine showed a time trend at 1-year follow-up (24 evaluations) indicating a significantly lower level of aggressive behavior. Patient higher compliance was also associated with lower Modified Overt Aggression Scale ratings during the 1-year follow-up.

CONCLUSION

Both inpatients and outpatients showed high levels of polypharmacy. Clozapine prescription was associated with lower Modified Overt Aggression Scale ratings compared with any other antipsychotics or other psychotropic drugs. Higher compliance was associated with lower levels of aggressive and violent behavior.

The association of memory disorders and chronic HIV disease in the antiretroviral therapy era: a systematic literature review

OBJECTIVES

Despite recent pharmacological progress, memory impairment is still frequently reported in people living with HIV. We aimed to conduct a systematic literature review investigating the presence of impairment of (sub)components of memory function in patients prescribed highly active antiretroviral therapy (ART).

METHODS

We adopted a cognitive neuropsychological model of memory function as the theoretical framework, distinguishing between a short-term working memory component and a long-term component of memory, along with their specific (sub)components. We systematically searched for the presence of impairment of each (sub)component in the selected papers. Careful consideration was given to study design and methods and control of covariates.

RESULTS

Only the central executive component of working memory has been consistently reported to be impaired in HIV infection. The other two (sub)components, namely the phonological loop and the visuospatial sketchpad, were unimpaired. Discordant results have been obtained as to verbal and visual episodic memory, as some authors reported an association with HIV infection, whereas others did not. There is little evidence for semantic memory deficit in HIV infection, while there are suggestions that the neural substrate of implicit memory may be damaged by the effects of HIV infection and inflammation. Most studies in this area have been conducted in small samples and with poor control for covariates. Thus, conclusions regarding the association of memory dysfunction with HIV infection are hampered by methodological issues such as selection bias and unmeasured confounding.

CONCLUSIONS

The task remains for future research to ascertain the impact of HIV infection on memory function.

Tel1/ATM Signaling to the Checkpoint Contributes to Replicative Senescence in the Absence of Telomerase

Telomeres progressively shorten at every round of DNA replication in the absence of telomerase. When they become critically short, telomeres trigger replicative senescence by activating a DNA damage response that is governed by the Mec1/ATR and Tel1/ATM protein kinases. While Mec1/ATR is known to block cell division when extended single-stranded DNA (ssDNA) accumulates at eroded telomeres, the molecular mechanism by which Tel1/ATM promotes senescence is still unclear. By characterizing a Tel1-hy184 mutant variant that compensates for the lack of Mec1 functions, we provide evidence that Tel1 promotes senescence by signaling to a Rad9-dependent checkpoint. Tel1-hy184 anticipates senescence onset in telomerase-negative cells, while the lack of Tel1 or the expression of a kinase-defective (kd) Tel1 variant delays it. Both Tel1-hy184 and Tel1-kd do not alter ssDNA generation at telomeric DNA ends. Furthermore, Rad9 and (only partially) Mec1 are responsible for the precocious senescence promoted by Tel1-hy184. This precocious senescence is mainly caused by the F1751I, D1985N, and E2133K amino acid substitutions, which are located in the FRAP-ATM-TRAPP domain of Tel1 and also increase Tel1 binding to DNA ends. Altogether, these results indicate that Tel1 induces replicative senescence by directly signaling dysfunctional telomeres to the checkpoint machinery.

Real-world effectiveness of long acting aripiprazole: Treatment persistence and its correlates in the Italian clinical practice

OBJECTIVES

To identify the variables that are associated with persistence to Aripiprazole-Long Acting (A-LAI), in adult patients with schizophrenia.

METHODS

Observational, retrospective, non-interventional study involving 261 patients with schizophrenia.

RESULTS

Eighty-six percent of study subjects were persistent for at least 6 months. All subjects with baseline CGI-S of 1 or 2, 95% of subjects with CGI-S of 3, 86% with CGI-S of 4, 82% of subjects with CGI-S of 5, 73% of subjects with CGI of 6 and 90% of subjects with CGI of 7 were persistent. A-LAI treatment continuation rate was higher in patients with: 1) baseline CGI score ≤ 4; 2) schizophrenia dimension (LDPS) mania score ≤ 5; 3) psychotic spectrum schizoid score ≤ 11.

CONCLUSIONS

A relatively high number of patients (n = 225, 86%) were persistent to A-LAI for at least 6 months. Not surprisingly, very severe patients were more unlikely to be persistent. However, it is noteworthy that a large number of subjects with high CGI score at the time when A-LAI was started (82% of subjects with CGI-S of 5, 73% of subjects with CGI of 6 and 90% of subjects with CGI of 7) were persistent. Larger, controlled, prospective and longer studies are warranted.

Hemostatic abnormalities in patients with Ehlers-Danlos syndrome

Essentials Ehlers-Danlos Syndrome (EDS) is a rare heterogeneous group of inherited collagen disorders. A cohort of EDS patients was investigated for bleeding tendency and hemostatic abnormalities. EDS is associated with an increased risk of bleeding. EDS patients have platelet function abnormalities, whose severity correlates with bleeding risk. SUMMARY: Background Ehlers-Danlos syndrome (EDS) includes a heterogeneous group of connective tissue disorders affecting skin, bones, vessels, and other organs. Patients with EDS have an increased risk of bleeding, but a comprehensive study of hemostasis in EDS patients is lacking. Objective To investigate the bleeding tendency of a cohort of patients with EDS by using the Bleeding Assessment Tool of the ISTH, the bleeding severity score (BSS). Methods The BSS was defined as abnormal when it was ≥ 4 in men and ≥ 6 in women. Patients with a bleeding tendency were compared with those without in terms of type and number of hemostatic abnormalities. Results Fifty-nine of 141 patients with EDS (41.7%) had an abnormal BSS. Prothrombin time and activated partial thromboplastin time were slightly prolonged in 10 patients (7.1%) because of mild coagulation factor deficiencies, which were not responsible for the bleeding diathesis. von Willebrand factor antigen, ristocetin cofactor, endogenous thrombin potential and platelet count were normal in all patients. At least one platelet function abnormality was found in 53 patients (90%) with an abnormal BSS and in 64 (78%) with a normal BSS (adjusted odds ratio [OR] 2.55, 95% confidence interval [CI] 0.87-7.48). The risk of bleeding progressively increased with the number of platelet function abnormalities, reaching an OR of 5.19 (95% CI 1.32-20.45) when more than three abnormalities were detected. Conclusions Our results show that nearly half of patients with EDS have an abnormal BSS, which, in 90% of cases, appear, at least in part, to be attributable to platelet function abnormalities. Abnormalities of primary hemostasis may contribute to the risk of bleeding in patients with EDS.

Processing of DNA Ends in the Maintenance of Genome Stability

DNA double-strand breaks (DSBs) are particularly hazardous lesions as their inappropriate repair can result in chromosome rearrangements, an important driving force of tumorigenesis. DSBs can be repaired by end joining mechanisms or by homologous recombination (HR). HR requires the action of several nucleases that preferentially remove the 5′-terminated strands at both DSB ends in a process called DNA end resection. The same nucleases are also involved in the processing of replication fork structures. Much of our understanding of these pathways has come from studies in the model organism Saccharomyces cerevisiae. Here, we review the current knowledge of the mechanism of resection at DNA DSBs and replication forks.

Tel1/ATM prevents degradation of replication forks that reverse after topoisomerase poisoning

In both yeast and mammals, the topoisomerase poison camptothecin (CPT) induces fork reversal, which has been proposed to stabilize replication forks, thus providing time for the repair of CPT-induced lesions and supporting replication restart. We show that Tel1, the Saccharomyces cerevisiae orthologue of human ATM kinase, stabilizes CPT-induced reversed forks by counteracting their nucleolytic degradation by the MRX complex. Tel1-lacking cells are hypersensitive to CPT specifically and show less reversed forks in the presence of CPT The lack of Mre11 nuclease activity restores wild-type levels of reversed forks in CPT-treated tel1Δ cells without affecting fork reversal in wild-type cells. Moreover, Mrc1 inactivation prevents fork reversal in wild-type, tel1Δ, and mre11 nuclease-deficient cells and relieves the hypersensitivity of tel1Δ cells to CPT Altogether, our data indicate that Tel1 counteracts Mre11 nucleolytic activity at replication forks that undergo Mrc1-mediated reversal in the presence of CPT.

Alkaline Denaturing Southern Blot Analysis to Monitor Double-Strand Break Processing

Generation of 3' single-stranded DNA (ssDNA) tails at the ends of a double-strand break (DSB) is essential to repair the break through accurate homology-mediated repair pathways. Several methods have been developed to measure ssDNA accumulation at a DSB in the budding yeast Saccharomyces cerevisiae. Here, we describe one of these assays, which is based on the inability of restriction enzymes to cleave ssDNA. Digestion of genomic DNA prepared at different time points after DSB generation leads to the formation of ssDNA fragments whose length increases as the 5' strand degradation proceeds beyond restriction sites. After the separation by electrophoresis on alkaline denaturing agarose gel, these ssDNA fragments can be visualized by hybridization with an RNA probe that anneals with the 3'-undegraded DSB strand. This assay allows a direct and comprehensive visualization of DSB end processing.

Patterns of Care and Survival in Non Small Cell Lung Cancer: 15 Years’ Experience in a General Hospital

Background

Transferring results derived from clinical research into practice is particularly difficult in lung cancer where clear indications for treatment are defined only for selected subgroups of patients. Studies on hospital-based lung cancer population could provide data for quantifying this issue.

Patients and methods

This was a follow-up study of consecutive, first-diagnosis cases referred to the in-and outpatient cancer clinics of a large italian general hospital between January 1975 and December 1990. Data were collected from medical records and recorded on ad hoc standardized forms. Analysis focused on changes in distribution over time of patient-related characteristics, prevalence of specific treatment strategies and survival of the study population.

Results

1345 primary non small cell lung cancer cases were reviewed and 1125 were fully evaluable. In early stages (510/1125, 45%) only 237 patients actually underwent surgery. In this group surgery increased from 36 to 69% whereas chemotherapy decreased from 58 to 15%. In the advanced group (615/1125, 55%) chemotherapy was the preferred treatment but combined modalities tripled over time (from 4 to 12%). No significant changes in survival were observed within each group over time.

Conclusion

Despite changes in the therapeutic approaches, mortality from lung cancer does not seem reduced over time. Since the proportion of cases that could potentially benefit from “active” treatments is small, for the large majority of patients a switch in clinical research from a cure to a careoriented strategy should be considered.

Cytogenetic Analysis in 28 Radically Operated Non-Small-Cell Lung Cancer: Preliminary Considerations

Twenty-eight radically operated non-small-cell lung cancer patients were analyzed with regard to chromosomal assessment and DNA content: in 13 cases, different quantitative/ qualitative chromosome alterations were found. In particular, in 12 cases marker chromosomes and cytogenetic abnormalities in euploid cells were demonstrated. The prognostic value of these findings will be aim of further studies.

Cardiac Toxicity of 5-Fluorouracil: A Study on 1083 Patients

The possible onset of cardiotoxic manifestations during chemotherapy with 5-fluorouracil (5-FU) was evaluaetd in 1083 patients treated with the drug for various kinds of neoplasm. We recognized 17 cases of 5-FU cardiopathy (usually anginous crises but also myocardial infarction). The comprehensive incidence was 1.6 %, with a significantly greater risk (4.5 % vs 1.1 %) for patients with a positive anamnesis of previous cardiopathy. On the contrary, age and combination with other antiblastic drugs had no affect on the appearance of cardiopathy. We conclude that 5-FU cardiopathy, although rare, has to be taken into account in oncologic practice, chiefly in those patients already affected with cardiac diseases.

Phase II Study of the Activity and Tolerability of a Combined Regimen of High-Dose Epirubicin and Cisplatin in Stage IIIb and IV Non-Small Cell Lung Cancer

AIM

To explore the feasibility and activity of a combined regimen of high-dose epirubicin and cisplatin as an alternative to current treatments for non-small cell lung cancer (NSCLC).

METHOD

Forty-four patients with stage IIIb or IV NSCLC, median Karnofsky index 90, were enrolled. Epirubicin (60 mg/m2) was administered on days 1 and 2 and cisplatin (100 mg/m2) on day 1. Treatment was repeated every 21 days for a maximum of six cycles. A hematopoietic growth factor (G-CSF) was used only for patients reaching codified nadir count values.

RESULTS

A total of 130 cycles were administered with a mean of 2.9 cycles per patient. Of 41 assessable patients one showed a complete response and 15 had partial responses (overall response rate, 39%). Grade 3 or 4 leukopenia and grade 3 hemoglobin toxicity were seen in 40% and 14%, respectively, of the administered cycles. The most common nonhematologic toxic events were nausea and vomiting, mucositis, anorexia, and asthenia.

CONCLUSIONS

This epirubicin-cisplatin regimen seemed effective and was generally well tolerated, and therefore suitable for use in an outpatient setting.

The RNA binding protein Npl3 promotes resection of DNA double-strand breaks by regulating the levels of Exo1

Eukaryotic cells preserve genome integrity upon DNA damage by activating a signaling network that promotes DNA repair and controls cell cycle progression. One of the most severe DNA damage is the DNA double-strand break (DSB), whose 5΄ ends can be nucleolitically resected by multiple nucleases to create 3΄-ended single-stranded DNA tails that trigger DSB repair by homologous recombination. Here, we identify the Saccharomyces cerevisiae RNA binding protein Npl3 as a new player in DSB resection. Npl3 is related to both the metazoan serine-arginine-rich and the heterogeneous nuclear ribonucleo-proteins. NPL3 deletion impairs the generation of long ssDNA tails at the DSB ends, whereas it does not exacerbate the resection defect of exo1Δ cells. Furthermore, either the lack of Npl3 or the inactivation of its RNA-binding domains causes decrease of the exonuclease Exo1 protein levels as well as generation of unusual and extended EXO1 RNA species. These findings, together with the observation that EXO1 overexpression partially suppresses the resection defect of npl3Δ cells, indicate that Npl3 participates in DSB resection by promoting the proper biogenesis of EXO1 mRNA.

Controlling hybrid nonlinearities in transparent conducting oxides via two-colour excitation

Nanophotonics and metamaterials have revolutionized the way we think about optical space (ε,μ), enabling us to engineer the refractive index almost at will, to confine light to the smallest of the volumes, and to manipulate optical signals with extremely small footprints and energy requirements. Significant efforts are now devoted to finding suitable materials and strategies for the dynamic control of the optical properties. Transparent conductive oxides exhibit large ultrafast nonlinearities under both interband and intraband excitations. Here we show that combining these two effects in aluminium-doped zinc oxide via a two-colour laser field discloses new material functionalities. Owing to the independence of the two nonlinearities, the ultrafast temporal dynamics of the material permittivity can be designed by acting on the amplitude and delay of the two fields. We demonstrate the potential applications of this novel degree of freedom by dynamically addressing the modulation bandwidth and optical spectral tuning of a probe optical pulse.

Metamaterials have enabled the tailored engineering of optical properties. Here, Clerici et al. show that independent interband and intraband nonlinearities in transparent conducting oxides allow dynamic optical control of the real and imaginary parts of the refractive index.

Higher uric acid serum levels are associated with better muscle function in the oldest old: Results from the Mugello Study

BACKGROUND

Sarcopenia is the progressive loss of muscle mass and strength that occurs with advancing age and plays a pivotal role in the causal pathway leading to frailty, disability and, eventually, to death among older persons. As oxidative damage of muscle proteins has been shown to be a relevant contributory factor, in this study we hypothesized that uric acid (UA), a powerful endogenous antioxidant, might exert a protective effect on muscle function in the oldest old and we tested our hypothesis in a group of nonagenarians who participated in the Mugello Study.

METHODS

239 subjects, 73 men and 166 women, mean age 92.8years±SD 3.1, underwent the assessment of UA serum level and isometric handgrip strength, a widely used clinical measure of sarcopenia.

RESULTS

Mean UA serum level was 5.69mg/dL±SD 1.70 and mean handgrip strength was 15.0kg±SD 6.9. After adjusting for relevant confounders, higher UA serum levels remained independent positive predictors of isometric handgrip strength (β 1.24±SE(β) 0.43, p=0.005).

CONCLUSION

Our results show that higher UA serum levels are associated with better muscle function in the oldest old and, accordingly, might slow down the progression of sarcopenia.

Abuse During Childhood and Burnout

Background

Childhood maltreatment is the most important risk factor for the onset of psychiatric disorders. Revictimization is really frequent as well as substance or alcohol abuse, often linked to self-treatment. Accordingly, our pilot study aims to analyze possible implication of childhood maltreatment on resilience and burnout.

Methods

Patients admitted to outpatients psychiatric department in a six month period (1st January 2015–30th June 2015) complaining low to moderate anxiety or depression have been administered childhood trauma questionnaire (CTQ) and Maslach burnout inventory.

Results

CTQ results in 71 (87%) Emotional Neglect (EN), 2 (2.4%) Sexual Abuse (SA) and 2 (2.4%) Physical Abuse (PA). Twenty-one showed high emotional exhaustion, 21 high depersonalization, 9 moderate personal accomplishment while 1 showed low personal accomplishment. None of the patients who suffered child sexual abuse shows depersonalization or personal accomplishment difficulties linked to burnout. Patients negative to CTQ show respectively moderate emotional exhaustion (M = 20 ± 20.15), moderate depersonalization (11 ± 9.42) and high personal accomplishment (17 ± 12.38). Patients who suffered emotional neglect show the poorest profile at Maslach, particularly regarding emotional exhaustion. ANOVA reaches statistical significance among the 3 groups of detected abuse (EN, SA, PA) in personal accomplishment (P = 0.013) confirmed at POST HOC between EN and SA (P = 0.0004).

Conclusion

The results obtained in this pilot study highlight two important considerations. First, it seems urgent to stress the huge prevalence of emotional neglect among those referred to psychiatric outpatient department due to moderate anxiety or depression complain. Moreover, emotional neglect appears to be the most compromised factor of burnout, especially if compared to sexual abuse.

Personality Disorders and Perinatal Psychiatry: Food for Thoughts from Perinatal Psychiatric Department Experience

Background

Pregnancy and postpartum are sensitive unique moments in women's life. Perinatal psychiatry is focused on depression and psychosis, but personality issues is often neglected as well as risk factors for personality disorders instead of being considered causative of onset or recrudescence of psychiatric symptoms in perinatal.

Methods

In total, 129 women were referred to perinatal psychiatric department during their pregnancy or postpartum in the last three years. They were administered SCID II, Childhood Trauma Questionnaire (CTQ), Beck Depression and Anxiety Inventories (BDI and BAI), Edinburgh Postnatal Depression Scale (EPDS) and World Health Organization Quality of Life (WHOQOL). Their interaction with babies was monitored at birth and during follow up. Children's behavioral development is under evaluation through structured tests.

Results

BDI and BAI scored moderate or severe in 31 and 27% of women, EPDS was significant in 36%, while SCID II highlighted 24% of borderline, 17% narcissistic, 4% schizoid, 4% paranoid and 9% obsessive/compulsive PD. Nineteen of them suffered physical abuse during childhood, 26 sexual abuse, 89 emotional neglect and only 15 out of 129 were negative to any kind of abuse during childhood.

Conclusion

Personality disorders appears to influence maternal adjustment to pregnancy and motherhood. Abuses suffered during childhood confirm their role as potential risk factor in personality issues which clearly express their effect in adaptation to change in personal role and in emphatic interactions.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Immunomodulatory effects of pidotimod in adults with community-acquired pneumonia undergoing standard antibiotic therapy

The morbidity and mortality of community-acquired pneumonia (CAP) are still elevated and two aspects seem to contribute to a worse outcome: an uncontrolled inflammatory reaction and an inadequate immune response. Adjuvants, including corticosteroids and intravenous immunoglobulins, have been proposed to counterbalance these effects but their efficacy is only partial. We examined the immunomodulatory activity of Pidotimod (PDT), a synthetic dipeptide molecule in adult patients hospitalized for CAP. Sixteen patients with a diagnosis of CAP and a PSI score III or IV and/or a CURB-65 0-2 were randomized to receive either levofloxacin 500 mg b.i.d. alone or levofloxacin plus PDT (800mg, 2 daily doses). Blood samples were drawn at baseline (T0), before initiation of therapy, as well as 3 (T3), and 5 (T5) days after initiation of therapy. Immunologic and clinical parameters were analyzed at each time point. Supplementation of antibiotic therapy with PDT resulted in an upregulation of antimicrobial and of immunomodulatory proteins as well as in an increased percentage of Toll like receptor (TLR)2- and TLR4, and of CD80- and CD86-expressing immune cells. Notably, Pidotimod supplementation was also associated with a robust reduction of TNFα-producing immune cells. No significant differences were observed in clinical parameters. These results confirm that supplementation of antibiotic therapy with Pidotimod in patients with CAP results in a potentially beneficial modulation of innate immunity.

Optically induced metal-to-dielectric transition in Epsilon-Near-Zero metamaterials

Epsilon-Near-Zero materials exhibit a transition in the real part of the dielectric permittivity from positive to negative value as a function of wavelength. Here we study metal-dielectric layered metamaterials in the homogenised regime (each layer has strongly subwavelength thickness) with zero real part of the permittivity in the near-infrared region. By optically pumping the metamaterial we experimentally show that close to the Epsilon-Near-Zero (ENZ) wavelength the permittivity exhibits a marked transition from metallic (negative permittivity) to dielectric (positive permittivity) as a function of the optical power. Remarkably, this transition is linear as a function of pump power and occurs on time scales of the order of the 100 fs pump pulse that need not be tuned to a specific wavelength. The linearity of the permittivity increase allows us to express the response of the metamaterial in terms of a standard third order optical nonlinearity: this shows a clear inversion of the roles of the real and imaginary parts in crossing the ENZ wavelength, further supporting an optically induced change in the physical behaviour of the metamaterial.

Enhanced Nonlinear Refractive Index in ε-Near-Zero Materials

New propagation regimes for light arise from the ability to tune the dielectric permittivity to extremely low values. Here, we demonstrate a universal approach based on the low linear permittivity values attained in the ε-near-zero (ENZ) regime for enhancing the nonlinear refractive index, which enables remarkable light-induced changes of the material properties. Experiments performed on Al-doped ZnO (AZO) thin films show a sixfold increase of the Kerr nonlinear refractive index (n_{2}) at the ENZ wavelength, located in the 1300 nm region. This in turn leads to ultrafast light-induced refractive index changes of the order of unity, thus representing a new paradigm for nonlinear optics.

Upregulation of inflammasome activity and increased gut permeability are associated with obesity in children and adolescents

BACKGROUND

Immune activation contributes to the persistent state of inflammation associated with metabolic dysfunction in obesity. The specific immune receptors that sense metabolic stress signals and trigger inflammation are nevertheless largely unknown, and little is known on inflammatory and immune gene regulation in obesity.

METHODS

The study includes a cross-sectional and a longitudinal arm. Forty children and adolescents were enrolled: 22 obese subjects and 18 age-matched normal weight controls. Obese subjects participated in an 18-month therapeutic protocol, based on intensive lifestyle modification (dietary regimen, physical activity and behavioral interventions). Expression of genes involved in the inflammasome pathway, plasma concentration of the inflammasome-associated pro-inflammatory cytokines (interleukin (IL)-1β and IL-18) and indexes of microbial translocation (lipopolysaccharide (LPS), soluble CD14 (sCD14) and intestinal fatty acid-binding protein) were analyzed at baseline in obese subjects compared with controls, and after 18 months in obese subjects.

RESULTS

Cross-sectional analyses showed that the LPS-induced expression of genes involved in inflammasome (NLRP3, caspase 5 and NAIP), Nod-like receptors (NLRX1 and NOD1), downstream signaling (P2RX7, RAGE, RIPk2, TIRAP and BIRC2) and effector molecules (IFN-γ, IL-12β, IL-1β, CCL2, CCL5, IL-6 and TNFα) was significantly increased in obese subjects at baseline as compared with normal weight controls. The baseline plasma concentration of inflammasome-related cytokines (IL-1β and IL-18) and of microbial translocation markers (LPS and sCD14) was augmented in obese subjects as compared with controls as well. Longitudinal analyses indicated that intensive lifestyle modification resulted in a normalization of parameters in subjects with a significant reduction of BMI after 18 months.

CONCLUSIONS

In children and adolescents, obesity is characterized by the activation of the inflammasome and by an alteration of gut permeability. Successful lifestyle modification is effective in reducing inflammation, suggesting that inhibition of the inflammasome may be a potential therapeutic strategy in obesity.

The thrombin generation assay distinguishes inhibitor from non-inhibitor patients with severe haemophilia A

INTRODUCTION

Patients with haemophilia A (HA) have impaired thrombin generation (TG) capacity and TG assay (TGA) values are linearly related to plasma factor VIII (FVIII) levels.

AIM

This study carried out in patients with unmeasurable FVIII (<1 IU dL(-1) ) was aimed at unravelling any difference in TG capacity in patients with or without inhibitors.

METHODS

Blood samples were collected from patients in a non-bleeding state, after a 5-day wash-out period from last treatment.

RESULTS

TGA was performed in 102 patients with severe HA (15% with high-responding inhibitors; 51% with null F8 mutations, that as expected were more prevalent in inhibitor than in non-inhibitor patients). TG capacity was significantly lower in inhibitor than non-inhibitor patients and in those with null mutations than in those with non-null mutations. When the TG capacity was evaluated only in patients with null mutations with and without inhibitors it was lower in the presence of inhibitors.

CONCLUSIONS

This study shows a greater TG impairment in inhibitor patients irrespective of FVIII levels, inhibitor titre and F8 mutation type, suggesting a role for the TGA in unravelling functional interferences of anti-FVIII inhibitors on coagulation system activation.

Tel1 and Rif2 Regulate MRX Functions in End-Tethering and Repair of DNA Double-Strand Breaks

The cellular response to DNA double-strand breaks (DSBs) is initiated by the MRX/MRN complex (Mre11-Rad50-Xrs2 in yeast; Mre11-Rad50-Nbs1 in mammals), which recruits the checkpoint kinase Tel1/ATM to DSBs. In Saccharomyces cerevisiae, the role of Tel1 at DSBs remains enigmatic, as tel1Δ cells do not show obvious hypersensitivity to DSB-inducing agents. By performing a synthetic phenotype screen, we isolated a rad50-V1269M allele that sensitizes tel1Δ cells to genotoxic agents. The MR^V1269MX complex associates poorly to DNA ends, and its retention at DSBs is further reduced by the lack of Tel1. As a consequence, tel1Δ rad50-V1269M cells are severely defective both in keeping the DSB ends tethered to each other and in repairing a DSB by either homologous recombination (HR) or nonhomologous end joining (NHEJ). These data indicate that Tel1 promotes MRX retention to DSBs and this function is important to allow proper MRX-DNA binding that is needed for end-tethering and DSB repair. The role of Tel1 in promoting MRX accumulation to DSBs is counteracted by Rif2, which is recruited to DSBs. We also found that Rif2 enhances ATP hydrolysis by MRX and attenuates MRX function in end-tethering, suggesting that Rif2 can regulate MRX activity at DSBs by modulating ATP-dependent conformational changes of Rad50.

This study reveals novel roles for the checkpoint kinase Tel1/ATM and Rif2 in regulating the function of the MRX complex during repair of DNA double-strand breaks by nonhomologous end joining and homologous recombination.

Many tumors contain mutations that confer defects in repairing DNA double-strand breaks (DSBs). In both yeast and mammals, the MRX/MRN complex (Mre11-Rad50-Xrs2 in yeast; Mre11-Rad50-Nbs1 in mammals) plays critical functions in repairing a DSB by either nonhomologous end joining (NHEJ) or homologous recombination (HR). Furthermore, it recruits the checkpoint kinase Tel1/ATM. Although ATM is considered to be a tumor suppressor, up-regulation of ATM signaling promotes chemoresistance, radioresistance and metastasis. For this reason, cancer therapies targeting ATM have been developed to increase the effectiveness of standard genotoxic treatments and/or to set up synthetic lethal approaches in cancers with DNA repair defects. We aimed to identify the precise role of ATM/Tel1 in these processes. By performing a synthetic phenotype screen, we identified a mutation (rad50-V1269M) altering the Rad50 subunit of the MRX complex, which sensitizes cells lacking Tel1 to genotoxic agents. Genetic and biochemical characterization of MR^V1269MX protein complex revealed that Tel1 promotes MRX association at DSBs to allow proper MRX-DNA binding that is needed for DSB repair. The role of Tel1 in promoting MRX retention on DSBs is counteracted by Rif2, which can regulate MRX activity at DSBs by modulating ATP-dependent conformational changes in Rad50. Our finding that MRX dysfunctions can be synthetically lethal with Tel1 loss in the presence of genotoxic agents suggests that ATM inhibitors could be beneficial in patients whose tumors have defective MRN functions.

Sae2 Function at DNA Double-Strand Breaks Is Bypassed by Dampening Tel1 or Rad53 Activity

The MRX complex together with Sae2 initiates resection of DNA double-strand breaks (DSBs) to generate single-stranded DNA (ssDNA) that triggers homologous recombination. The absence of Sae2 not only impairs DSB resection, but also causes prolonged MRX binding at the DSBs that leads to persistent Tel1- and Rad53-dependent DNA damage checkpoint activation and cell cycle arrest. Whether this enhanced checkpoint signaling contributes to the DNA damage sensitivity and/or the resection defect of sae2Δ cells is not known. By performing a genetic screen, we identify rad53 and tel1 mutant alleles that suppress both the DNA damage hypersensitivity and the resection defect of sae2Δ cells through an Sgs1-Dna2-dependent mechanism. These suppression events do not involve escaping the checkpoint-mediated cell cycle arrest. Rather, defective Rad53 or Tel1 signaling bypasses Sae2 function at DSBs by decreasing the amount of Rad9 bound at DSBs. As a consequence, reduced Rad9 association to DNA ends relieves inhibition of Sgs1-Dna2 activity, which can then compensate for the lack of Sae2 in DSB resection and DNA damage resistance. We propose that persistent Tel1 and Rad53 checkpoint signaling in cells lacking Sae2 increases the association of Rad9 at DSBs, which in turn inhibits DSB resection by limiting the activity of the Sgs1-Dna2 resection machinery.

Genome instability is one of the most pervasive characteristics of cancer cells and can be due to DNA repair defects and failure to arrest the cell cycle. Among the many types of DNA damage, the DNA double strand break (DSB) is one of the most severe, because it can cause mutations and chromosomal rearrangements. Generation of DSBs triggers a highly conserved mechanism, known as DNA damage checkpoint, which arrests the cell cycle until DSBs are repaired. DSBs can be repaired by homologous recombination, which requires the DSB ends to be nucleolytically processed (resected) to generate single-stranded DNA. In Saccharomyces cerevisiae, DSB resection is initiated by the MRX complex together with Sae2, whereas more extensive resection is catalyzed by both Exo1 and Dna2-Sgs1. The absence of Sae2 not only impairs DSB resection, but also leads to the hyperactivation of the checkpoint proteins Tel1/ATM and Rad53, leading to persistent cell cycle arrest. In this manuscript we show that persistent Tel1 and Rad53 signaling activities in sae2Δ cells cause DNA damage hypersensitivity and defective DSB resection by increasing the amount of Rad9 bound at the DSBs, which in turn inhibits the Sgs1-Dna2 resection machinery. As ATM inhibition has been proposed as a strategy for cancer treatment, the finding that defective Tel1 signaling activity restores DNA damage resistance in sae2Δ cells might have implications in cancer therapies that use ATM inhibitors for synthetic lethal approaches that are devised to kill tumor cells with defective DSB repair.

Resection is responsible for loss of transcription around a double-strand break in Saccharomyces cerevisiae

Emerging evidence indicate that the mammalian checkpoint kinase ATM induces transcriptional silencing in cis to DNA double-strand breaks (DSBs) through a poorly understood mechanism. Here we show that in Saccharomyces cerevisiae a single DSB causes transcriptional inhibition of proximal genes independently of Tel1/ATM and Mec1/ATR. Since the DSB ends undergo nucleolytic degradation (resection) of their 5'-ending strands, we investigated the contribution of resection in this DSB-induced transcriptional inhibition. We discovered that resection-defective mutants fail to stop transcription around a DSB, and the extent of this failure correlates with the severity of the resection defect. Furthermore, Rad9 and generation of γH2A reduce this DSB-induced transcriptional inhibition by counteracting DSB resection. Therefore, the conversion of the DSB ends from double-stranded to single-stranded DNA, which is necessary to initiate DSB repair by homologous recombination, is responsible for loss of transcription around a DSB in S. cerevisiae.