A Tunable Mechanism Determines the Duration of the Transgenerational Small RNA Inheritance in C. elegans.

In C. elegans, small RNAs enable transmission of epigenetic responses across multiple generations. While RNAi inheritance mechanisms that enable "memorization" of ancestral responses are being elucidated, the mechanisms that determine the duration of inherited silencing and the ability to forget the inherited epigenetic effects are not known. We now show that exposure to dsRNA activates a feedback loop whereby gene-specific RNAi responses dictate the transgenerational duration of RNAi responses mounted against unrelated genes, elicited separately in previous generations. RNA-sequencing analysis reveals that, aside from silencing of genes with complementary sequences, dsRNA-induced RNAi affects the production of heritable endogenous small RNAs, which regulate the expression of RNAi factors. Manipulating genes in this feedback pathway changes the duration of heritable silencing. Such active control of transgenerational effects could be adaptive, since ancestral responses would be detrimental if the environments of the progeny and the ancestors were different.

m6A is required for resolving progenitor identity during planarian stem cell differentiation.

Regeneration and tissue homeostasis require accurate production of missing cell lineages. Cell production is driven by changes to gene expression, which is shaped by multiple layers of regulation. Here, we find that the ubiquitous mRNA base-modification, m6A, is required for proper cell fate choice and cellular maturation in planarian stem cells (neoblasts). We mapped m6A-enriched regions in 7,600 planarian genes and found that perturbation of the m6A pathway resulted in progressive deterioration of tissues and death. Using single-cell RNA sequencing of >20,000 cells following perturbation of the m6A pathway, we identified an increase in expression of noncanonical histone variants, and that inhibition of the pathway resulted in accumulation of undifferentiated cells throughout the animal in an abnormal transcriptional state. Analysis of >1,000 planarian gene expression datasets revealed that the inhibition of the chromatin modifying complex NuRD had almost indistinguishable consequences, unraveling an unappreciated link between m6A and chromatin modifications. Our findings reveal that m6A is critical for planarian stem cell homeostasis and gene regulation in tissue maintenance and regeneration.

Cannabis and Complex Posttraumatic Stress Disorder: A Narrative Review With Considerations of Benefits and Harms.

Despite substantial controversies concerning patients' reports of benefits from cannabis for posttraumatic stress disorder (PTSD) and inconsistent research findings regarding its efficacy and adverse risks, some states have already recognized PTSD as a qualifying condition for medical cannabis. Consequently, medical cannabis can also be provided for patients with complex PTSD who experience additional posttraumatic symptoms of affective dysregulation, negative perception of the self, and difficulties in relationships due to a history of repetitive trauma. In this article, we explore cannabis use in relation to benefits versus harms that might occur relative to specific complex PTSD symptoms and comorbidities. Whereas some symptoms related to PTSD per se (e.g., anxiety, insomnia, nightmares) may be benefited, others that are more characteristic of complex PTSD (e.g., dissociation, reckless behavior, and substance abuse associated with dysregulated affect) may be aggravated. Therefore, clinicians treating patients with complex PTSD who use or seek cannabis should carefully assess patients' motivations and the impacts of particular use patterns on specific symptoms. Clinicians and patients should be aware of and fully discuss the significant number of potential adverse effects of cannabis use, several of which might impede patients' participation in beneficial psychotherapeutic, social, and medical interventions.

Addressing Loneliness in Complex PTSD.

Loneliness impacts both physical and psychological health and is associated with increases of all-cause mortality and suicidal behavior. Because loneliness may result from a variety of developmental, interpersonal, and intrapersonal factors, distinguishing its components, origins, and sustaining factors as it manifests in various psychopathological states are important steps in formulating interventions to alleviate these conditions. To date, loneliness has not been widely studied in relation to complex posttraumatic stress disorder (PTSD), which is newly delineated in the International Classification of Diseases, characterized by PTSD symptoms in the context of significant early trauma, as well as "disturbances in self-organization" marked by affective dysregulation, negative self-concept, and disturbances in relationships. In this article, illustrating with case material, we suggest that loneliness plays a major role in the development of complex PTSD and in the preservation of its symptoms. Consequently, therapies for complex PTSD should include interventions that address loneliness.

Severe bupropion XR abuse in a patient with long-standing bulimia nervosa and complex PTSD.

OBJECTIVE: Although abuse of bupropion to achieve euphoria or a stimulant-like effect has been described in the literature, to our knowledge abuse of bupropion XR to control binge eating and reduce appetite by a patient with eating disorder has not been previously reported. METHOD: We report the case of a 22-year-old woman with bulimia nervosa and complex PTSD who abused bupropion XR to doses that at peak reached 3,000-4,500 mg/day. She suffered from adverse effects including headaches, tachycardia, anxiety, insomnia, and, finally, grand mal seizures. RESULTS: Unable to control the abuse on her own, she sought inpatient treatment, following which she remained off bupropion XR for a year. However, she subsequently relapsed. DISCUSSION: The stimulant, euphoriant, and anorexic effects of bupropion XR contribute to its potential for abuse, particularly among patients with eating disorders. Clinicians are reminded to screen for anorexia nervosa and bulimia nervosa histories prior to prescribing this medication, and to consider its abuse among eating disorder patients presenting with seizures. For patients abusing this medication, motivational interviewing in the context of a strong, ongoing therapeutic relationship might help to achieve sustained periods of abstinence.

Perioperative complications of emergent and elective procedures in psychiatric patients.

BACKGROUND: Patients with psychiatric disorders have an increased risk for morbidity and mortality from other medical conditions. METHODS: Medical records of all the patients undergoing appendectomy (n = 2594) and laparoscopic cholecystectomy (n = 2874) from 2009 to 2014 in one hospital were reviewed. For each patient with a documented psychiatric disorder undergoing surgery, four controls were matched. RESULTS: The final sample of patients undergoing appendectomy included 96 patients, whereas those undergoing laparoscopic cholecystectomy included 260 patients. In the emergent scenario, psychiatric patients had longer time from symptom appearance to admission, longer hospitalization duration, and increased rate and severity of postoperative complications. In the elective scenario, psychiatric patients were shown to have more postoperative respiratory complications. CONCLUSIONS: Our results, together with the high prevalence of psychiatric disorders in the population, underscore the importance of screening for psychiatric disorders and their proper documentation in surgical patients.

Cost of resistance to trematodes in freshwater snail populations with low clonal diversity.

BACKGROUND: The persistence of high genetic variability in natural populations garners considerable interest among ecologists and evolutionary biologists. One proposed hypothesis for the maintenance of high levels of genetic diversity relies on frequency-dependent selection imposed by parasites on host populations (Red Queen hypothesis). A complementary hypothesis suggests that a trade-off between fitness costs associated with tolerance to stress factors and fitness costs associated with resistance to parasites is responsible for the maintenance of host genetic diversity. RESULTS: The present study investigated whether host resistance to parasites is traded off with tolerance to environmental stress factors (high/low temperatures, high salinity), by comparing populations of the freshwater snail Melanoides tuberculata with low vs. high clonal diversity. Since polyclonal populations were found to be more parasitized than populations with low clonal diversity, we expected them to be tolerant to environmental stress factors. We found that clonal diversity explained most of the variation in snail survival under high temperature, thereby suggesting that tolerance to high temperatures of clonally diverse populations is higher than that of populations with low clonal diversity. CONCLUSIONS: Our results suggest that resistance to parasites may come at a cost of reduced tolerance to certain environmental stress factors.

Development of APE1 enzymatic DNA repair assays: low APE1 activity is associated with increase lung cancer risk.

The key role of DNA repair in removing DNA damage and minimizing mutations makes it an attractive target for cancer risk assessment and prevention. Here we describe the development of a robust assay for apurinic/apyrimidinic (AP) endonuclease 1 (APE1; APEX1), an essential enzyme involved in the repair of oxidative DNA damage. APE1 DNA repair enzymatic activity was measured in peripheral blood mononuclear cell protein extracts using a radioactivity-based assay, and its association with lung cancer was determined using conditional logistic regression with specimens from a population-based case-control study with 96 lung cancer cases and 96 matched control subjects. The mean APE1 enzyme activity in case patients was 691 [95% confidence interval (CI) = 655-727] units/ng protein, significantly lower than in control subjects (mean = 793, 95% CI = 751-834 units/ng protein, P = 0.0006). The adjusted odds ratio for lung cancer associated with 1 SD (211 units) decrease in APE1 activity was 2.0 (95% CI = 1.3-3.1; P = 0.002). Comparison of radioactivity- and fluorescence-based assays showed that the two are equivalent, indicating no interference by the fluorescent tag. The APE1Asp148Glu SNP was associated neither with APE1 enzyme activity nor with lung cancer risk. Taken together, our results indicate that low APE1 activity is associated with lung cancer risk, consistent with the hypothesis that 'bad DNA repair', rather than 'bad luck', is involved in cancer etiology. Such assays may be useful, along with additional DNA repair biomarkers, for risk assessment of lung cancer and perhaps other cancers, and for selecting individuals to undergo early detection techniques such as low-dose CT.

Enzymatic MPG DNA repair assays for two different oxidative DNA lesions reveal associations with increased lung cancer risk.

DNA repair is a major mechanism for minimizing mutations and reducing cancer risk. Here, we present the development of reproducible and specific enzymatic assays for methylpurine DNA glycosylase (MPG) repairing the oxidative lesions 1,N6-ethenoadenine (εA) and hypoxanthine (Hx) in peripheral blood mononuclear cells protein extracts. Association of these DNA repair activities with lung cancer was determined using conditional logistic regression with specimens from a population-based case-control study with 96 lung cancer cases and 96 matched control subjects. The mean MPG-εA in case patients was 15.8 units/µg protein (95% CI 15.3-16.3), significantly higher than in control subjects-15.1 (14.6-15.5), *P = 0.011. The adjusted odds ratio for lung cancer associated with a one SD increase in MPG-εA activity (2.48 units) was significantly bigger than 1 (OR = 1.6, 95% CI = 1.1-2.4; *P = 0.013). When activity of OGG1, a different DNA repair enzyme for oxidative damage, was included in the model, the estimated odds ratio/SD for a combined MPG-εA-OGG1 score was 2.6 (95% CI 1.6-4.2) *P = 0.0001, higher than the odds ratio for each single assay. The MPG enzyme activity assays described provide robust functional risk biomarkers, with increased MPG-εA activity being associated with increased lung cancer risk, similar to the behavior of MPG-Hx. This underscores the notion that imbalances in DNA repair, including high DNA repair, usually perceived as beneficial, can cause cancer risk. Such DNA repair risk biomarkers may be useful for risk assessment of lung cancer and perhaps other cancer types, and for early detection techniques such as low-dose CT.

DNA Repair Biomarker for Lung Cancer Risk and its Correlation With Airway Cells Gene Expression.

BACKGROUND: Improving lung cancer risk assessment is required because current early-detection screening criteria miss most cases. We therefore examined the utility for lung cancer risk assessment of a DNA Repair score obtained from OGG1, MPG, and APE1 blood tests. In addition, we examined the relationship between the level of DNA repair and global gene expression. METHODS: We conducted a blinded case-control study with 150 non-small cell lung cancer case patients and 143 control individuals. DNA Repair activity was measured in peripheral blood mononuclear cells, and the transcriptome of nasal and bronchial cells was determined by RNA sequencing. A combined DNA Repair score was formed using logistic regression, and its correlation with disease was assessed using cross-validation; correlation of expression to DNA Repair was analyzed using Gene Ontology enrichment. RESULTS: DNA Repair score was lower in case patients than in control individuals, regardless of the case's disease stage. Individuals at the lowest tertile of DNA Repair score had an increased risk of lung cancer compared to individuals at the highest tertile, with an odds ratio (OR) of 7.2 (95% confidence interval [CI] = 3.0 to 17.5; P < .001), and independent of smoking. Receiver operating characteristic analysis yielded an area under the curve of 0.89 (95% CI = 0.82 to 0.93). Remarkably, low DNA Repair score correlated with a broad upregulation of gene expression of immune pathways in patients but not in control individuals. CONCLUSIONS: The DNA Repair score, previously shown to be a lung cancer risk factor in the Israeli population, was validated in this independent study as a mechanism-based cancer risk biomarker and can substantially improve current lung cancer risk prediction, assisting prevention and early detection by computed tomography scanning.

Posttraumatic Growth in Complex PTSD.

Objective: Although efforts have been made to study mechanisms and mediators of posttraumatic growth (PTG - positive sequelae of coping with trauma), little has been done to investigate PTG as a concept in the context of complex PTSD, a disorder recently delineated in ICD11. This article considers PTG in relation to complex PTSD, primarily as associated with childhood sexual abuse. Method: Using clinical case material and available literature, we explore the emergence of PTG in the treatment of patients with complex PTSD and examine factors contributing to its appearance. Results: Despite extensive early traumas, including those associated with histories of ongoing childhood sexual abuse, patients may be capable of PTG. While factors favoring PTG may include temperamental resilience and other as yet ill-defined personality traits, the presence of safe, supportive and enduring therapeutic and extra-therapeutic relationships, appear to address insecure attachments related to trauma and be of considerable importance in fostering possibilities for PTG. Conclusions: While much remains to be learned, encouraging and helping establish varieties of accepting, trusting and nurturing contacts in real world and psychotherapy and introducing and exploring the concept of PTG within therapy, can help patients suffering from complex PTSD address the underlying developmental deficiencies they have endured, facilitate treatment, and promote PTG.

Development of an enzymatic DNA repair assay for molecular epidemiology studies: distribution of OGG activity in healthy individuals.

While the role of reduced DNA repair in susceptibility to hereditary cancers is well established, its role in sporadic cancer is less understood. One of the reasons is the lack of specific DNA repair assays that are suitable for epidemiology studies. Here we describe the development of the OGG test, an epidemiology-grade enzymatic assay for the activity of the base excision repair enzyme 8-oxoguanine DNA glycosylase, in protein extracts prepared from human blood cells. The assay is robust and reproducible, with a coefficient of variation of 10%. Using the OGG test we determined OGG activity in 120 healthy individuals. Our results show an inter-individual variation of 2.8-fold in OGG activity, from 3.6 up to 10.1units/microg protein, with a mean value of 7.2units/microg protein. There was no significant difference in OGG activity between males and females, or between smokers and non-smokers. Interestingly, there was a gender-specific effect of age: OGG activity was slightly but significantly lower in males older than the age of 55 years compared to younger males, but not in females at the same age groups. Analysis of OGG1 mRNA by quantitative real-time RT-PCR showed a group trend of an increase in OGG enzymatic activity with increasing mRNA expression, but the correlation between activity and mRNA in individuals was poor, indicating the importance of factors other than mRNA expression. The OGG test described is expected to be useful in studying the role of 8-oxoguanine repair in cancer, as recently demonstrated for non-small cell lung cancer [T. Paz-Elizur, M. Krupsky, S. Blumenstein, D. Elinger, E. Schechtman, Z. Livneh, J. Natl. Cancer Inst. 95 (2003) 1312-1319]. In addition, it may serve as a paradigm for the development of additional functional DNA repair tests, which are needed in order to gain further insight into the role of DNA repair in cancer risk and pathology.

DNA repair of oxidative DNA damage in human carcinogenesis: potential application for cancer risk assessment and prevention.

Efficient DNA repair mechanisms comprise a critical component in the protection against human cancer, as indicated by the high predisposition to cancer of individuals with germ-line mutations in DNA repair genes. This includes biallelic germ-line mutations in the MUTYH gene, encoding a DNA glycosylase that is involved in the repair of oxidative DNA damage, which strongly predispose humans to a rare hereditary form of colorectal cancer. Extensive research efforts including biochemical, enzymological and genetic studies in model organisms established that the oxidative DNA lesion 8-oxoguanine is mutagenic, and that several DNA repair mechanisms operate to prevent its potentially mutagenic and carcinogenic outcome. Epidemiological studies on the association with sporadic cancers of single nucleotide polymorphisms in genes such as OGG1, involved in the repair of 8-oxoguanine yielded conflicting results, and suggest a minor effect at best. A new approach based on the functional analysis of DNA repair enzymatic activity showed that reduced activity of 8-oxoguanine DNA glycosylase (OGG) is a risk factor in lung and head and neck cancer. Moreover, the combination of smoking and low OGG activity was associated with a higher risk, suggesting a potential strategy for risk assessment and prevention of lung cancer, as well as other types of cancer.

DNA sequence context greatly affects the accuracy of bypass across an ultraviolet light 6-4 photoproduct in mammalian cells.

Translesion DNA synthesis (TLS) is a DNA damage tolerance mechanism carried out by low-fidelity DNA polymerases that bypass DNA lesions, which overcomes replication stalling. Despite the miscoding nature of most common DNA lesions, several of them are bypassed in mammalian cells in a relatively accurate manner, which plays a key role maintaining a low mutation load. Whereas it is generally agreed that TLS across the major UV and sunlight induced DNA lesion, the cyclobutane pyrimidine dimer (CPD), is accurate, there were conflicting reports on whether the same is true for the thymine-thymine pyrimidine-pyrimidone(6-4) ultraviolet light photoproduct (TT6-4PP), which represents the second most common class of UV lesions. Using a TLS assay system based on gapped plasmids carrying site-specific TT6-4PP lesions in defined sequence contexts we show that the DNA sequence context markedly affected both the extent and accuracy of TLS. The sequence exhibiting higher TLS exhibited also higher error-frequency, caused primarily by semi-targeted mutations, at the nearest nucleotides flanking the lesion. Our results resolve the discrepancy reported on TLS across TT6-4PP, and suggest that TLS is more accurate in human cells than in mouse cells.

Low integrated DNA repair score and lung cancer risk.

DNA repair is a prime mechanism for preventing DNA damage, mutation, and cancers. Adopting a functional approach, we examined the association with lung cancer risk of an integrated DNA repair score, measured by a panel of three enzymatic DNA repair activities in peripheral blood mononuclear cells. The panel included assays for AP endonuclease 1 (APE1), 8-oxoguanine DNA glycosylase (OGG1), and methylpurine DNA glycosylase (MPG), all of which repair oxidative DNA damage as part of the base excision repair pathways. A blinded population-based case-control study was conducted with 96 patients with lung cancer and 96 control subjects matched by gender, age (±1 year), place of residence, and ethnic group (Jews/non-Jews). The three DNA repair activities were measured, and an integrated DNA repair OMA (OGG1, MPG, and APE1) score was calculated for each individual. Conditional logistic regression analysis revealed that individuals in the lowest tertile of the integrated DNA repair OMA score had an increased risk of lung cancer compared with the highest tertile, with OR = 9.7; 95% confidence interval (CI), 3.1-29.8; P < 0.001, or OR = 5.6; 95% CI, 2.1-15.1; P < 0.001 after cross-validation. These results suggest that pending validation, this DNA repair panel of risk factors may be useful for lung cancer risk assessment, assisting prevention and referral to early detection by technologies such as low-dose computed tomography scanning.

Randomized sham controlled trial of repetitive transcranial magnetic stimulation to the dorsolateral prefrontal cortex for the treatment of panic disorder with comorbid major depression.

BACKGROUND: In an open-label trial low-frequency repetitive transcranial magnetic stimulation (rTMS) to the right dorsolateral prefrontal cortex (DLPFC) significantly improved symptoms of panic disorder and major depression. Here we present data of a randomized double-blind study. METHODS: Twenty-five patients were assigned 4 weeks of active or sham rTMS to the right DLPFC. rTMS parameters consisted of 1800 stimuli/day, 1-Hz, at 110% of resting motor threshold. Response was defined as a ≥40% decrease on the panic disorder severity scale and a ≥50% decrease on the Hamilton depression rating scale. At the end of the randomized phase, patients were offered the option of receiving open-label rTMS for an additional 4 weeks. RESULTS: Repeated-measures ANOVA revealed significantly better improvement in panic symptoms with active compared with sham rTMS, but no significant difference in depression. At 4 weeks, response rate for panic disorder was 50% with active rTMS and 8% with sham. After 8 weeks of active rTMS, response rate was 67% for panic and 50% for depressive symptoms. Repeated-measure ANOVA showed significant improvements in panic disorder, major depression, clinical global impression, and social adjustment. Clinical improvement was sustained at 6-month follow-up. LIMITATIONS: Limitation of this study is the relatively small sample size. CONCLUSIONS: Although 4 weeks of rTMS was sufficient to produce a significant effect in panic symptoms, a longer course of treatment resulted in better outcomes for both panic disorder and major depression. These data suggest that inhibitory rTMS to the right DLPFC affects symptoms expression in comorbid anxiety and depression. ClinicalTrials.gov Identifier: NCT00521352.

N-methylpurine DNA glycosylase and OGG1 DNA repair activities: opposite associations with lung cancer risk.

Only a minority of smokers develop lung cancer, possibly due to genetic predisposition, including DNA repair deficiencies. To examine whether inter-individual variations in DNA repair activity of N-methylpurine DNA glycosylase (MPG) are associated with lung cancer, we conducted a blinded, population-based, case-control study with 100 lung cancer case patients and 100 matched control subjects and analyzed the data with conditional logistic regression. All statistical tests were two-sided. MPG enzyme activity in peripheral blood mononuclear cells from case patients was higher than in control subjects, results opposite that of 8-oxoguanine DNA glycosylase (OGG1) DNA repair enzyme activity. For lung cancer associated with one standard deviation increase in MPG activity, the adjusted odds ratio was 1.8 (95% confidence interval [CI] = 1.2 to 2.6; P = .006). A combined MPG and OGG1 activities score was more strongly associated with lung cancer risk than either activity alone, with an odds ratio of 2.3 (95% CI = 1.4 to 3.6; P < .001). These results form a basis for a future panel of risk biomarkers for lung cancer risk assessment and prevention.

Expression and functional analyses of the plastid lipid-associated protein CHRC suggest its role in chromoplastogenesis and stress.

Chromoplastogenesis during flower development and fruit ripening involves the dramatic overaccumulation of carotenoids sequestered into structures containing lipids and proteins called plastid lipid-associated proteins (PAPs). CHRC, a cucumber (Cucumis sativus) PAP, has been suggested to be transcriptionally activated in carotenoid-accumulating flowers by gibberellin (GA). Mybys, a MYB-like trans-activator identified here, may represent a chromoplastogenesis-related factor: Its expression is flower specific and parallels that of ChrC during flower development; moreover, as revealed by stable ectopic and transient-expression assays, it specifically trans-activates ChrC promoter in flowers accumulating carotenoids and flavonoids. A detailed dissection of ChrC promoter revealed a GA-responsive element, gacCTCcaa, the mutation of which abolished ChrC activation by GA. This cis-element is different from the GARE motif and is involved in ChrC activation probably via negative regulation, similar to other GA-responsive systems. The GA responsiveness and MYBYS floral activation of the ChrC promoter do not overlap with respect to cis-elements. To study the functionality of CHRC, which is activated in vegetative tissues similar to other PAPs by various biotic and abiotic stresses, we employed a tomato (Lycopersicon esculentum) plant system and generated RNAi-transgenic lines with suppressed LeCHRC. Transgenic flowers accumulated approximately 30% less carotenoids per unit protein than controls, indicating an interrelationship between PAPs and flower-specific carotenoid accumulation in chromoplasts. Moreover, the transgenic LeCHRC-suppressed plants were significantly more susceptible to Botrytis cinerea infection, suggesting CHRC's involvement in plant protection under stress conditions and supporting the general, evolutionarily preserved role of PAPs.