The mitochondrial RNA granule modulates manganese-dependent cell toxicity

Prolonged manganese exposure causes manganism, a neurodegenerative movement disorder. The identity of adaptive and nonadaptive cellular processes targeted by manganese remains mostly unexplored. Here we study mechanisms engaged by manganese in genetic cellular models known to increase susceptibility to manganese exposure, the plasma membrane manganese efflux transporter SLC30A10 and the mitochondrial Parkinson's gene PARK2. We found that SLC30A10 and PARK2 mutations as well as manganese exposure compromised the mitochondrial RNA granule composition and function, resulting in disruption of mitochondrial transcript processing. These RNA granule defects led to impaired assembly and function of the mitochondrial respiratory chain. Notably, cells that survived a cytotoxic manganese challenge had impaired RNA granule function, thus suggesting that this granule phenotype was adaptive. CRISPR gene editing of subunits of the mitochondrial RNA granule, FASTKD2 or DHX30, as well as pharmacological inhibition of mitochondrial transcription-translation, were protective rather than deleterious for survival of cells acutely exposed to manganese. Similarly, adult Drosophila mutants with defects in the mitochondrial RNA granule component scully were safeguarded from manganese-induced mortality. We conclude that impairment of the mitochondrial RNA granule function is a protective mechanism for acute manganese toxicity.

Abstract P5-11-10: Evaluation of the relationship between psychological distress and risk for breast cancer

Introduction: Women at increased risk for breast cancer (due to family history or having a pathogenic germline mutation in a cancer causing gene) have greater distress levels, which can impact quality of life and screening behavior. The goal of our study was to evaluate distress related to different risk factors for breast cancer and examine the stability of this distress over time.

Methods: Women at increased risk for breast cancer who enrolled in the High-Risk Breast Program (HRBP) at the University of Vermont Medical Center were eligible for participation. Women with strong family history, a genetic mutation or atypia on biopsy (benign breast disease, BBD) who completed the Impact of Event Scale (IES) at least once were identified. The IES is a self-reported measure designed to measure subjective distress within the past seven days in relation to a stressor. The scale is based on a two-factor intrusion-avoidance model. Linear regression was used to examine change in distress over time and to compare distress levels between risk groups. Both risk measures and distress scores were examined using bivariate plots and normal probability plots. Pearson correlation coefficients and least squares regression coefficients were obtained along with 95% confidence intervals. In addition to treating the risk estimates as continuous measures, these estimates were grouped into low or average risk (<=2%) over five years, moderate risk (2%-4%) over five years, and high risk (>=5%) over five years. Using the ordinal classification into three risk groups, analysis of variance was conducted to detect group differences in average psychological distress using a 5% significance level.

Results: The cohort comprised 344 women at increased risk for breast cancer due to a strong family history (80%), a genetic mutation (9%) or benign breast disease (16%). Mean IES score was 16.8 (CI 15.5, 18.2), and indicates high distress levels in this cohort. IES scores decreased over time (p<0.001 and p=0.003 after 4 and 8 years, respectively). Scores did not differ between the overall group and either women with a strong family history (p=0.06) or women with BBD (p=0.8). Women with genetic mutations had higher IES scores than those without (p=0.023). IES scores were positively associated with the number of risk factors an individual had (1, 2, or 3 risk factors: p=0.003).

Conclusion: We demonstrated that distress is similar among different risk categories and that distress decreases over time; patterns not previously recognized. Women with benign breast disease have IES scores similar to women with strong family histories of breast cancer. Women with multiple risk factors are also noted to have higher scores. Women with genetic mutations appear to have the highest distress levels. These findings further our understanding of cancer related distress. Targeting women with highest distress levels may improve both quality of life and screening adherence.

Citation Format: Vennard K, Crocker A, Ogheneruona A, Cuke M, Wood M. Evaluation of the relationship between psychological distress and risk for breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-11-10.

The safety and efficacy of early-initiation exercise training after acute venous thromboembolism: a randomized clinical trial

BACKGROUND

Exercise training after myocardial infarction is the standard of care within a cardiac rehabilitation setting. However, there is scant evidence regarding the safety and efficacy of early exercise training following a venous thromboembolism (VTE).

METHODS

Eligible consenting participants were randomly allocated, on an individual basis, to either a 3-month exercise and behavioral weight loss intervention group or a control group. The primary clinical outcomes were change in health behavior (body weight and physical activity) and objectively measured fitness (Vo2peak ).

RESULTS

From 2013 to 2014, 239 patients presented to a community-based specialty clinic after an acute VTE; 43 (18%) of these met the eligibility criteria for inclusion in the study. Of these, 19 (44%) consented to participate (nine in the intervention group; 10 in the control group). There were no adverse events in either group over a 3-month period. The mean difference in body weight between the intervention and control groups was - 4.6 kg (95% confidence interval [CI] - 11.4 to 2.2) in favor of the intervention. The mean difference in duration of physical activity from baseline to 3 months between the intervention and control groups was 133 min (95% CI 7-248) in favor of the intervention. There was a significant change in fitness over a 3-month period for the intervention group (baseline Vo2peak , 26.1 ± 5.4 mL O2 kg(-1)  min(-1) ; postintervention Vo2peak , 29.8 ± 5.4 mL O2 kg(-1)  min(-1) ).

CONCLUSION

Early initiation of exercise training resulted in improvements in physical activity and fitness, and did not result in adverse events while individuals were receiving therapeutic anticoagulation. These are the first data on initiation of an exercise training and behavioral weight loss program in the early post-VTE setting.

Molecular analysis of sleep: wake cycles in Drosophila

Sleep is controlled by two major regulatory systems: a circadian system that drives it with a 24-hour periodicity and a home-ostatic system that ensures that adequate amounts of sleep are obtained. We are using the fruit fly Drosophila melanogaster to understand both types of regulation. With respect to circadian control, we have identified molecular mechanisms that are critical for the generation of a clock. Our recent efforts have focused on the analysis of posttranslational mechanisms, specifically the action of different phosphatases that control the phosphorylation and thereby the stability and/or nuclear localization of circadian clock proteins period (PER) and timeless (TIM). Resetting the clock in response to light is also mediated through posttranslational events that target TIM for degradation by the proteasome pathway; a recently identified ubiquitin ligase, jet lag (JET), is required for this response. Our understanding of the homeostatic control of sleep is in its early stages. We have found that mushroom bodies, which are a site of synaptic plasticity in the fly brain, are important for the regulation of sleep. In addition, through analysis of genes expressed under different behavioral states, we have identified some that are up-regulated during sleep deprivation. Thus, the Drosophila model allows the use of cellular and molecular approaches that should ultimately lead to a better understanding of sleep biology.

Concomitant loss of dynorphin, NARP, and orexin in narcolepsy

BACKGROUND

Narcolepsy with cataplexy is associated with a loss of orexin/hypocretin. It is speculated that an autoimmune process kills the orexin-producing neurons, but these cells may survive yet fail to produce orexin.

OBJECTIVE

To examine whether other markers of the orexin neurons are lost in narcolepsy with cataplexy.

METHODS

We used immunohistochemistry and in situ hybridization to examine the expression of orexin, neuronal activity-regulated pentraxin (NARP), and prodynorphin in hypothalami from five control and two narcoleptic individuals.

RESULTS

In the control hypothalami, at least 80% of the orexin-producing neurons also contained prodynorphin mRNA and NARP. In the patients with narcolepsy, the number of cells producing these markers was reduced to about 5 to 10% of normal.

CONCLUSIONS

Narcolepsy with cataplexy is likely caused by a loss of the orexin-producing neurons. In addition, loss of dynorphin and neuronal activity-regulated pentraxin may contribute to the symptoms of narcolepsy.

Fitness, responsibility, and judicially ordered assessments

OBJECTIVE

To compare the characteristics of individuals assessed for fitness to stand trial (FST) with those assessed for criminal responsibility (CR).

METHOD

This study examines all the consecutive requests of FST or CR addressed to the only forensic psychiatric hospital in the province of Quebec and 2 prisons in the Montreal area over a 1-year period.

RESULTS

In all, 170 FST, 52 CR, and 29 both FST and CR assessment requests were received (251 subjects). Psychiatrists' recommendations and court verdicts of unfitness to stand trial or not criminally responsible on account of mental disorders were mostly related to the presence of a psychotic-spectrum disorder. There is generally a good agreement between psychiatric recommendations and verdicts of the court, with the exception of unfitness recommendations.

CONCLUSIONS

Defendants referred for a FST or a CR assessment displayed similar characteristics. However, although subjects with psychotic disorders represented more than one-half of the unfit or not criminally responsible verdicts, most of the subjects with psychoses were found competent to stand trial or responsible.

The wound management of patients with partial thickness burn injuries

A report on the treatment of two burn-injured patients using retention dressings as primary wound dressings

Interaction of nutrition and infection: effect of copper deficiency on resistance to Trypanosoma lewisi

The copper-deficient rat-trypanosome system was used to study copper deficiency in Sprague Dawley rats infected with Trypanosoma lewisi. Throughout the observational period, animals on the deficient diet had lower plasma and liver copper concentrations compared with complete and pair-fed animals. In all dietary groups, the food intake and body weight changes of rats inoculated with T lewisi showed significant increases over the noninoculated controls. The rate of these indices were significantly less in the copper-deficient animals compared with the animals fed complete diets. Copper-deficient and pair-fed control rats showed greater numbers of parasites than controls throughout the infection. The duration of the trypanosomal infection was longer in copper-deficient rats compared with other groups. In all of the dietary groups, severe depression in the primary and secondary antibody responses (IgM and IgG) to in vivo immunization with sheep erythrocytes was observed in infected animals over noninfected controls. The results of the present study indicate that during copper deficiency, there are significant changes in food consumption and body weight and enhanced susceptibility to infection as measured by an increased parasitemia and depression in the antibody responses.