The role of GAPDH in maintaining the functional state of the DNA repair enzyme APE1

Les sites apuriniques/apyrimidiniques (AP) sont des sites de l’ADN hautement mutagène. Les dommages au niveau de ces sites peuvent survenir spontanément ou être induits par une variété d’agents. Chez l’humain, les sites AP sont réparés principalement par APE1, une enzyme de réparation de l’ADN qui fait partie de la voie de réparation par excision de base (BER). APE1 est une enzyme multifonctionnelle; c’est une AP endonucléase, 3’-diestérase et un facteur redox impliqué dans l’activation des facteurs de transcription. Récemment, il a été démontré qu’APE1 interagit avec l’enzyme glycolytique GAPDH. Cette interaction induit l’activation d’APE1 par réduction. En outre, la délétion du gène GAPDH sensibilise les cellules aux agents endommageant l’ADN, induit une augmentation de formation spontanée des sites AP et réduit la prolifération cellulaire. A partir de toutes ces données, il était donc intéressant d’étudier l’effet de la délétion de GAPDH sur la progression du cycle cellulaire, sur la distribution cellulaire d’APE1 et d’identifier la cystéine(s) d’APE1 cible(s) de la réduction par GAPDH. Nos travaux de recherche ont montré que la déficience en GAPDH cause un arrêt du cycle cellulaire en phase G1. Cet arrêt est probablement dû à l’accumulation des dommages engendrant un retard au cours duquel la cellule pourra réparer son ADN. De plus, nous avons observé des foci nucléaires dans les cellules déficientes en GAPDH qui peuvent représenter des agrégats d’APE1 sous sa forme oxydée ou bien des focis de la protéine inactive au niveau des lésions d’ADN. Nous avons utilisé la mutagénèse dirigée pour créer des mutants (Cys en Ala) des sept cystéines d’APE1 qui ont été cloné dans un vecteur d’expression dans les cellules de mammifères. Nous émettons l’hypothèse qu’au moins un mutant ou plus va être résistant à l’inactivation par oxydation puisque l’alanine ne peut pas s’engager dans la formation des ponts disulfures. Par conséquent, on anticipe que l’expression de ce mutant dans les cellules déficientes en GAPDH pourrait restaurer une distribution cellulaire normale de APE1, libérerait les cellules de l’arrêt en phase G1 et diminuerait la sensibilité aux agents endommageant l’ADN. En conclusion, il semble que GAPDH, en préservant l’activité d’APE1, joue un nouveau rôle pour maintenir l’intégrité génomique des cellules aussi bien dans les conditions normales qu’en réponse au stress oxydatif.Apurinic/apyrimidinic (AP) sites are highly mutagenic DNA lesions occurring either spontaneously or by the action of DNA damaging agents. In human cells, AP sites are processed by the major DNA repair enzyme APE1 through the base excision repair (BER) pathway. APE1 is a multifunctional protein that has AP endonuclease/3’-diesterase activities in addition to its role as a redox factor in activating many transcription factor. Recently, it has been shown that APE1 interacts with the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH), an interaction that results in the activation of APE1 by reduction. Interestingly, depletion of GAPDH sensitized the cells to DNA damaging agents and induced an increase in spontaneous AP sites frequency. Moreover, cells knocked-down for GAPDH showed defects in proliferation. Here we set up to investigate the effects of GAPDH knockdown on cell cycle progression, APE1 subcellular localization and to identify the cysteine residue(s) of APE1, target(s) of GAPDH reduction. Our studies showed that GAPDH deficient cells arrested in G1 phase of the cell cycle. The defect in cell cycle progression is most probably due to accumulation of DNA damage which activates checkpoints leading to a delay in the cell cycle to allow DNA repair. Furthermore, in GAPDH deficient cells, APE1 formed nuclear foci-like structures that could represent aggregates of the oxidized form of APE1 or inactive APE1 foci on DNA lesions. Using site-directed mutagenesis, we created seven APE1 cysteine to alanine mutants which were cloned into a mammalian expression vector. We expect that at least one of these mutants is likely to resist the inactivation by oxidation as it cannot engage in disulfide bridge formation. Therefore, the expression of this mutant(s) in GAPDH knockdown cells is expected to restore a normal APE1 cellular distribution, rescue the cell cycle defects, and render the cells less sensitive to DNA damaging agents. In conclusion, our results show a new role of GAPDH in maintaining genomic stability under oxidative stress by maintaining APE1 in its functional state

AT THE NEXUS OF LAW AND ETHICS: A PROPOSED JUDICIAL STANDARD FOR COURT-ORDERED CESAREAN SECTIONS

Maternal-fetal conflicts, specifically court-ordered Cesarean sections, are explored from a legal and ethical perspective. An increase in technology, combined with the rise of bioethics, the respect for autonomy in medical decision-making, and the legal doctrine of informed consent have created an atmosphere in which conflicts may occur between the pregnant woman and her fetus. The scant legal precedent in this area does not provide a clear standard for evaluating cases in which a pregnant woman with a viable fetus refuses a recommended Cesarean section. The analysis first examines the clinical aspects of a Cesarean delivery, and then turns to a discussion of the legal precedent and the potentially analogous areas of law (i.e. abortion, parent-child relationships, and organ donation). In addition, there is an examination of the ethical and policy considerations, which weigh heavily in favor of honoring the pregnant woman's wishes over the perceived benefit for the fetus. Finally, a judicial standard is proposed which combines the legal and ethical analyses, and concludes that a court should virtually never override a competent patient's decision to refuse a Cesarean section

Sensorimotor adaptation to auditory perturbation of speech is facilitated by noninvasive brain stimulation

Repeated exposure to disparity between the motor plan and auditory feedback during speech production results in a proportionate change in the motor system’s response called auditory-motor adaptation. Artificially raising F1 in auditory feedback results in a concomitant decrease in F1 during speech production. Transcranial direct current stimulation (tDCS) can be used to alter neuronal excitability in focal areas of the brain. The present experiment explored the effect of noninvasive brain stimulation applied to the speech premotor cortex on the timing and magnitude of adaptation responses to artificially raised F1 in auditory feedback. Participants (N = 18) completed a speaking task in which they read target words aloud. Participants' speech was processed to raise F1 by 30% and played back to them over headphones in real time. A within-subjects design compared acoustics of participants’ speech while receiving anodal (active) tDCS stimulation versus sham (control) stimulation. Participants' speech showed an increasing magnitude of adaptation of F1 over time during anodal stimulation compared to sham. These results indicate that tDCS can affect behavioral response during auditory-motor adaptation, which may have translational implications for sensorimotor training in speech disorders

Medical Students’ Perceptions, Knowledge, and Competence in Treating Neurodivergent, Disability, and Chronic Illness (NDCI) Populations: Results from a Cross-Sectional Study

Background: Globally, Neurodivergent, Disability, and Chronic Illness (NDCI) populations face significant health disparities. Lack of physician knowledge about NDCI is a key mechanism underlying these disparities. The current study aimed to describe medical students’ perceptions, knowledge, and competence regarding NDCI. Methods: A cross-sectional study was carried out using an online survey of medical students at a large public university with no NDCI-specific curriculum (n = 97; response rate = 18%). The survey asked about students’ perceptions, knowledge, and competence pertaining to NDCI populations. Results: Most (n = 93, 96%) indicated it is important for physicians to understand the influence of NDCI on patient health and clinical encounters. Yet only seven (7%) and 15 (15%) reported that the NDCI curriculum in their medical school was sufficient, and they felt comfortable taking care of patients with NDCI respectively. Most (n = 87, 90%) wanted their medical school to provide additional NDCI training. Few reported high knowledge about ableism (n = 12, 12%), self-determination (n = 7, 7%), coordinating care (n = 4, 4%) and accommodations (n = 10, 10%). Few indicated high competence in cognitive, physical, social-emotional, and other NDCI types (n = 7 – 32, 7-33%). Existing knowledge often came from personal experiences or the news and media. Conclusion: Findings demonstrated the gaps in medical education, as exemplified by medical students surveyed in one U.S. public university. Results can inform efforts to ameliorate global health disparities associated with a lack of physician knowledge about NDCI

Adverse pregnancy outcomes associated with moderate elevations in blood pressure or blood glucose in Ugandan women; a prospective cohort study.

BACKGROUND: The association between overt hypertension and diabetes and adverse pregnancy outcomes is well documented. Recent evidence suggests that even moderate elevations in blood pressure or blood glucose may confer a significant risk in a dose-dependent manner. However, these studies have primarily been undertaken in white populations in high-income settings. Hypertension and diabetes are emerging as major public health issues in sub-Saharan Africa as the region undergoes rapid urbanization. It is therefore important to understand how such noncommunicable conditions contribute to pregnancy outcomes in these populations. OBJECTIVE: This study aimed to determine the association between stage 1 hypertension or fasting blood glucose in the gestational diabetes mellitus-range and adverse pregnancy outcomes in Uganda, and to describe the effects of other contributing factors such as maternal obesity. STUDY DESIGN: This was a prospective cohort study of 2857 women at 5 major hospitals in urban and semiurban central Uganda. Women were enrolled at 24 to 28 weeks' gestation. Data about the maternal demographics, anthropometrics, fasting venous blood glucose, blood pressure, and pregnancy outcomes were collected. Moderate elevations in blood pressure and blood glucose were defined using the latest American College of Cardiology and American Heart Association definition of stage 1 hypertension and the World Health Organization's criteria for fasting blood glucose in the gestational diabetes mellitus-range. The primary outcomes of interest were perinatal death and large birthweight for gestational age, and the secondary outcomes were preterm birth, cesarean delivery, and neonatal admission. A multivariable logistic regression analysis was used. RESULTS: Stage 1 hypertension increased the odds of perinatal death by more than 2-fold (adjusted odds ratio, 2.68; 95% confidence interval, 1.36-5.29), with a positive but insignificant association with preterm birth. Hyperglycemia in the gestational diabetes mellitus-range was associated with cesarean delivery only (adjusted odds ratio, 1.65; 95% confidence interval, 1.20-2.27). Maternal obesity increased the risk of having large birthweight babies (adjusted odds ratio, 2.30; 95% confidence interval, 1.74-3.02), a cesarean delivery (adjusted odds ratio, 2.75; 95% confidence interval, 2.17-3.48), and neonatal admission (adjusted odds ratio, 1.63; 95% confidence interval, 1.16-2.30). CONCLUSION: Moderate elevations in blood pressure and maternal obesity are stronger predictors of adverse maternal and neonatal outcomes than moderate elevations in blood glucose levels and should be the focus of intervention in these resource-poor settings. Further research is needed to determine the cost-effectiveness of identifying and managing moderate elevations in blood pressure and maternal obesity

Symptoms of post-traumatic stress and associations with sexual behaviour and PrEP preferences among young people in South Africa, Uganda and Zimbabwe.

BACKGROUND: It is not known whether post-traumatic stress disorder (PTSD) increases HIV-risk behaviours among young people in sub-Saharan Africa. We assessed associations of PTSD symptoms with sexual behaviour, HIV risk perception, and attitudes towards PrEP among young people taking part in the CHAPS community survey. We hypothesised that PTSD symptoms would increase sexual behaviours associated with HIV risk, hinder PrEP uptake and influence preference for daily versus on-demand PrEP. METHODS: Young people without HIV, aged 13-24 years, were purposively recruited in Johannesburg and Cape Town in South Africa, Wakiso in Uganda, and Chitungwiza in Zimbabwe, and surveyed on socio-demographic characteristics, PrEP knowledge and attitudes, sexual behaviour, HIV perception and salience, and mental health. PTSD symptoms were measured using the Primary Care PTSD Screen for the Diagnostic and Statistical Manual of Mental Disorders 5 (PC-PTSD-5). Logistic and ordinal logistic regression was used to assess associations between PC-PTSD-5 score and socio-demographic characteristics, sexual behaviour, HIV risk perception, PrEP attitudes, and substance use, adjusting for age, sex, setting, depression and anxiety. RESULTS: Of 1330 young people (51% male, median age 19 years), 522 (39%) reported at least one PTSD symptom. There was strong evidence that having a higher PC-PTSD-5 score was associated with reported forced sex (OR 3.18, 95%CI: 2.05-4.93), self-perception as a person who takes risks (OR 1.12, 95%CI: 1.04-1.20), and increased frequency of thinking about risk of HIV acquisition (OR 1.16, 95%CI: 1.08-1.25). PTSD symptoms were not associated with willingness to take PrEP, preference for on-demand versus daily PrEP, or actual HIV risk behaviour such as condomless sex. CONCLUSIONS: Symptoms consistent with probable PTSD were common among young people in South Africa, Uganda and Zimbabwe but did not impact PrEP attitudes or PrEP preferences. Evaluation for PTSD might form part of a general assessment in sexual and reproductive health services in these countries. More work is needed to understand the impact of PTSD on HIV-risk behaviour, forced sex and response to preventive strategies including PrEP

Antenatal management and maternal/fetal outcomes associated with hyperglycaemia in pregnancy (HIP) in Uganda; a prospective cohort study.

BACKGROUND: Hyperglycaemia in pregnancy (HIP) is associated with complications for both mother and baby. The prevalence of the condition is likely to increase across Africa as the continent undergoes a rapid demographic transition. However, little is known about the management and pregnancy outcomes associated with HIP in the region, particularly less severe forms of hyperglycaemia. It is therefore important to generate local data so that resources may be distributed effectively. The aim of this study was to describe the antenatal management and maternal/fetal outcomes associated with HIP in Ugandan women. METHODS: A prospective cohort study of 2917 pregnant women in five major hospitals in urban/semi-urban central Uganda. Women were screened with oral glucose tolerance test (OGTT) at 24-28 weeks of gestation. Cases of gestational diabetes (GDM) and diabetes in pregnancy (DIP) were identified (WHO 2013 diagnostic criteria) and received standard care. Data was collected on maternal demographics, anthropometrics, antenatal management, umbilical cord c-peptide levels, and pregnancy outcomes. RESULTS: Two hundred and seventy-six women were diagnosed with HIP (237 classified as GDM and 39 DIP). Women had between one and four fasting capillary blood glucose checks during third trimester. All received lifestyle advice, one quarter (69/276) received metformin therapy, and one woman received insulin. HIP was associated with large birthweight (unadjusted relative risk 1.30, 95% CI 1.00-1.68), Caesarean delivery (RR 1.34, 95% CI 1.14-1.57) and neonatal hypoglycaemia (RR 4.37, 95% CI 1.36-14.1), but not perinatal mortality or preterm birth. Pregnancy outcomes were generally worse for women with DIP compared with GDM. CONCLUSION: HIP is associated with significant adverse pregnancy outcomes in this population, particularly overt diabetes in pregnancy. However pregnancy outcomes in women with milder forms of hyperglycaemia are similar to those with normoglycaemic pregnancies. Intervention strategies are required to improve current monitoring and management practice, and more research needed to understand if this is a cost-effective way of preventing poor perinatal outcomes

Characterization of greater middle eastern genetic variation for enhanced disease gene discovery

The Greater Middle East (GME) has been a central hub of human migration and population admixture. The tradition of consanguinity, variably practiced in the Persian Gulf region, North Africa, and Central Asia1-3, has resulted in an elevated burden of recessive disease4. Here we generated a whole-exome GME variome from 1,111 unrelated subjects. We detected substantial diversity and admixture in continental and subregional populations, corresponding to several ancient founder populations with little evidence of bottlenecks. Measured consanguinity rates were an order of magnitude above those in other sampled populations, and the GME population exhibited an increased burden of runs of homozygosity (ROHs) but showed no evidence for reduced burden of deleterious variation due to classically theorized ‘genetic purging’. Applying this database to unsolved recessive conditions in the GME population reduced the number of potential disease-causing variants by four- to sevenfold. These results show variegated genetic architecture in GME populations and support future human genetic discoveries in Mendelian and population genetics

Addressing climate change with behavioral science:A global intervention tournament in 63 countries

Effectively reducing climate change requires marked, global behavior change. However, it is unclear which strategies are most likely to motivate people to change their climate beliefs and behaviors. Here, we tested 11 expert-crowdsourced interventions on four climate mitigation outcomes: beliefs, policy support, information sharing intention, and an effortful tree-planting behavioral task. Across 59,440 participants from 63 countries, the interventions' effectiveness was small, largely limited to nonclimate skeptics, and differed across outcomes: Beliefs were strengthened mostly by decreasing psychological distance (by 2.3%), policy support by writing a letter to a future-generation member (2.6%), information sharing by negative emotion induction (12.1%), and no intervention increased the more effortful behavior-several interventions even reduced tree planting. Last, the effects of each intervention differed depending on people's initial climate beliefs. These findings suggest that the impact of behavioral climate interventions varies across audiences and target behaviors.</p

Addressing climate change with behavioral science: a global intervention tournament in 63 countries

Effectively reducing climate change requires marked, global behavior change. However, it is unclear which strategies are most likely to motivate people to change their climate beliefs and behaviors. Here, we tested 11 expert-crowdsourced interventions on four climate mitigation outcomes: beliefs, policy support, information sharing intention, and an effortful tree-planting behavioral task. Across 59,440 participants from 63 countries, the interventions’ effectiveness was small, largely limited to nonclimate skeptics, and differed across outcomes: Beliefs were strengthened mostly by decreasing psychological distance (by 2.3%), policy support by writing a letter to a future-generation member (2.6%), information sharing by negative emotion induction (12.1%), and no intervention increased the more effortful behavior—several interventions even reduced tree planting. Last, the effects of each intervention differed depending on people’s initial climate beliefs. These findings suggest that the impact of behavioral climate interventions varies across audiences and target behaviors