Familial Alzheimer’s disease mutations in amyloid protein precursor alter proteolysis by γ-secretase to increase amyloid β-peptides of ≥45 residues

Production of amyloid β-protein (Aβ) is carried out by the membrane-embedded γ-secretase complex. Mutations in the transmembrane domain of amyloid β-protein precursor (APP) associated with early-onset familial Alzheimer's disease (FAD) can alter the ratio of aggregation-prone 42-residue Aβ (Aβ42) to 40-residue Aβ (Aβ40). However, APP substrate is proteolyzed processively by γ-secretase along two pathways: Aβ49→Aβ46→Aβ43→Aβ40 and Aβ48→Aβ45→Aβ42→Aβ38. Effects of FAD mutations on each proteolytic step are unknown, largely due to difficulties in detecting and quantifying longer Aβ peptides. To address this, we carried out systematic and quantitative analyses of all tri- and tetrapeptide coproducts from proteolysis of wild-type and 14 FAD-mutant APP substrates by purified γ-secretase. These small peptides, including FAD-mutant forms, were detected by tandem mass spectrometry and quantified by establishing concentration curves for each of 32 standards. APP intracellular domain (AICD) coproducts were quantified by immunoblot, and the ratio of AICD products corresponding to Aβ48 and Aβ49 was determined by mass spectrometry. Levels of individual Aβ peptides were determined by subtracting levels of peptide coproducts associated with degradation from those associated with production. This method was validated for Aβ40 and Aβ42 by specific ELISAs and production of equimolar levels of Aβ and AICD. Not all mutant substrates led to increased Aβ42/40. However, all 14 disease-causing mutations led to inefficient processing of longer forms of Aβ ≥ 45 residues. In addition, the effects of certain mutations provided insight into the mechanism of processive proteolysis: intermediate Aβ peptides apparently remain bound for subsequent trimming and are not released and reassociated

Selective Breeding to Improve Productive and Reproductive Performances and Survivability of Indigenous Sakini Chicken

Indigenous chickens are quite popular in Family Poultry Production System (FPPS) in Nepal, but are constrained with their low productive performance. The present study evaluated the productive and reproductive performance of Sakini chicken in different filial generations and sexes. In addition, research also aimed at understanding the effect of generations on above performances. Initially, base populations (G-0) of Sakini were maintained by collecting eight weeks old birds from different agro-ecologial zones of Nepal. Performance of the birds of G-0 was evaluated based on weekly body weight (12-24 weeks), laying performance, fertility, hatchability, hatch weight and survivability. Selected birds of base population (G-0) were used to produce first (G-1), second (G-2) and third (G-3) generations through selective breeding in each generation. Similarly, body weights at hatching, 12 weeks, 16 weeks, 20 week and 24 weeks were significantly (p<0.001) improved from G0 to G3 and were also significantly (p<0.001) differ for sex (males were always heavier than females). Likewise, there was significant (p<0.05) improvement in egg production (per hen per year), age at first lay (days), body weight at sexual maturity, egg number and egg weight at 90 days of laying in progressive generations. Fertility, hatchability and survivability significantly (p<0.05) improved in selected generations in comparison to base population, whereas, no significant difference was obtained within the different selected population. Thus, indigenous Sakini chicken under this experiment performed better with respect to survivability, fertility and hatchability in later generations that provides ample scope of advancing selective breeding activities within the indigenous population in order to bring significant improvement in the overall productive performance of Sakini chicken in Nepal

Sex trafficking in Nepal: A qualitative study of process and context. Abstract.

Thousands of Nepalese girls are trafficked to India and other neighbouring countries every year, primarily for sex work and the majority return to Nepal after spending a years in sex trade. The sub‐group of Nepalese girls who become involved in sex work via trafficking are the focus of this paper. The aim of this study was to increase understanding regarding the context of sex trafficking, the methods and means of trafficking, living conditions in brothels and survival strategies among trafficked girls. We conducted 33 in‐depth interviews in early 2013 with returned trafficking survivors (n=14) and policy‐makers, people working in trafficking related NGOs/INGOs (n=19) in Nepal. All 14 trafficking survivors were recruited in Nepal through the NGO working on trafficking field. The young girls trafficked from Nepal to India in this study were typically unmarried, illiterate and very young (8 to 14 years at the time of trafficking). The key methods of trafficking were false marriage, fake job offer, and abduction. Among the 14 respondents, some had spent one month and others nearly 5 years in Indian brothels. Respondents were either rescued, escaped or released by brothel owners. Four out of 14 were HIV positive. Most policy makers mentioned that poverty, unemployment and illiteracy are the causes behind the trafficking of young girls. The anti‐trafficking interventions need to be considered at a) community level before movement has begun; b) urban centres which are both source and transitory centres for trafficking; c) trafficking level when girls are highly mobile and when they are in brothels; and d) return from trafficking as girls to m ove back into the community

Effects of presenilin-1 familial Alzheimer’s disease mutations on γ-secretase activation for cleavage of amyloid precursor protein

Presenilin-1 (PS1) is the catalytic subunit of γ-secretase which cleaves within the transmembrane domain of over 150 peptide substrates. Dominant missense mutations in PS1 cause early-onset familial Alzheimer’s disease (FAD); however, the exact pathogenic mechanism remains unknown. Here we combined Gaussian accelerated molecular dynamics (GaMD) simulations and biochemical experiments to determine the effects of six representative PS1 FAD mutations (P117L, I143T, L166P, G384A, L435F, and L286V) on the enzyme-substrate interactions between γ-secretase and amyloid precursor protein (APP). Biochemical experiments showed that all six PS1 FAD mutations rendered γ-secretase less active for the endoproteolytic (ε) cleavage of APP. Distinct low-energy conformational states were identified from the free energy profiles of wildtype and PS1 FAD-mutant γ-secretase. The P117L and L286V FAD mutants could still sample the “Active” state for substrate cleavage, but with noticeably reduced conformational space compared with the wildtype. The other mutants hardly visited the “Active” state. The PS1 FAD mutants were found to reduce γ-secretase proteolytic activity by hindering APP residue L49 from proper orientation in the active site and/or disrupting the distance between the catalytic aspartates. Therefore, our findings provide mechanistic insights into how PS1 FAD mutations affect structural dynamics and enzyme-substrate interactions of γ-secretase and APP

Design of Substrate Transmembrane Mimetics as Structural Probes for γ-Secretase

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society (JACS), copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/jacs.9b13405.γ-Secretase is a membrane-embedded aspartyl protease complex central in biology and medicine. How this enzyme recognizes transmembrane substrates and catalyzes hydrolysis in the lipid bilayer is unclear. Inhibitors that mimic the entire substrate transmembrane domain and engage the active site should provide important tools for structural biology, yielding insight into substrate gating and trapping the protease in the active state. Here we report transmembrane peptidomimetic inhibitors of the γ-secretase complex that contain an N-terminal helical peptide region that engages a substrate docking exosite and a C-terminal transition-state analog moiety targeted to the active site. Both regions are required for stoichiometric inhibition of γ-secretase. Moreover, enzyme inhibition kinetics and photoaffinity probe displacement experiments demonstrate that both the docking exosite and the active site are engaged by the bipartite inhibitors. The solution conformations of these potent transmembranemimetic inhibitors are similar to those of bound natural substrates, suggesting these probes are preorganized for high-affinity binding and should allow visualization of the active γ-secretase complex, poised for intramembrane proteolysis, by cryo-electron microscopy.NIH R01 grant GM 122894NIH grant P30GM110761NIH grant P41GM11113

Needs assessment of mental health training for Auxiliary Nurse Midwives: a cross-sectional survey

Mental health in pregnant women and new mothers is increasing recognised on the global health agenda. In Nepal mental health is generally a difficult to topic to discuss. THET, a London-based organisation, funded Bournemouth University, and Liverpool John Moores University in the UK and Tribhuvan University in Nepal to train community-based maternity workers on issues around mental health. This paper reports on a quantitative survey with nearly all Auxiliary Nurse Midwives in Nawalparasi (southern part of Nepal). The findings illustrate the lack of training on mental health issues related to pregnancy and childbirth in this group of health workers. Thus the paper’s conclusions stress the need for dedicated training in this field

Ethnic Variations in Perception of Human Papillomavirus and its Vaccination among Young Women in Nepal

Background: The Human Papillomavirus (HPV) is strongly associated with cervical and other cancers. In women, cervical cancer is the third most common cancer. HPV infection can be largely prevented through vaccination of (adolescent) girls. At the same time, Nepal is a low-income country experiencing a cultural change in attitudes towards sex and sexual behaviour. However, in the adolescent population knowledge about HPV, factors associated with an increased risk of HPV and the existence of the vaccination is often low. Materials and Methods: This was a cross-sectional study with female students enrolled in health and non-health science courses in Pokhara, Nepal. The questionnaire included demographic details, knowledge and attitude questions related to HPV, associated risk behaviour and its vaccination. Descriptive statistics, including Chi-Square test, were used to identify statistically significant relationships. Ethical approval was granted by the relevant authority in Nepal. Results: Hindu religion (75.0 %; 95% CI: 70.9, 78.6) and Newari caste (75.5%; CI: 61.1, 86.7) were more aware about HPV, HPV vaccination. Hindus religion (55.6%; 95% CI: 51.2, 60.0) and Dalit caste (61.6%, 95% CI: 53.3, 69.4) more willing to be vaccinated than other religions and other castes, respectively. Not unsurprisingly, students on health-related courses had a greater awareness of HPV, HPV vaccination and were more willing to be vaccinated than students on other courses. Similar patterns of association arose for knowledge related to those sexually active at an early age; HPV risk and multiple sex partners; and fact that condoms cannot fully prevent the transmission of HPV. Conclusion: Knowledge about the link between HPV and (a) early sexual initiation, (b) having multiple sexual partners, and (c) the limited protection of condoms and other birth control measures was poor in our study compared to similar research conducted in other parts of the world. One key implication is the need for education campaigns in Nepal to educate young women and their parents about HPV, its risk factors and the benefits of vaccination

Time Trend of the Suicide Incidence in India: a Statistical Modelling

Background: It is estimated that over 100,000 people die by suicide in India every year. India alone contributes to more than 10% of suicides in the world. The suicide rate in India has been increasing steadily and has reached 11.2 (per 100,000 of population) in 2011 registering 78% increase over the value of 1980 (6.3). Objective: Objective of the study was to forecasts the suicide incidence of India up to 2020. Material and Methods: Theoretical statistics was used for the statistical modelling of the retrospective data of suicide incidence data of 1989-2011 years collected from National Crime Records Bureau (NCRB). Results: Using curve fitting method, Linear, Logarithmic, Inverse, Quadratic, Cubic, Compound, Power and Exponential growth models were validated. Cubic Model was the best fitted model with R2>0.90, p<0.01. Suicide incidence of India has an increasing trend. In 2020, it is estimated that the suicide incidence of India will be 109814 with CI [ 86,593, 133,034] for male, 76224 with CI [55,151, 97,297] for female and 186038 with CI [145,605, 226,471] for total [both male and female]. Conclusion: Suicide incidence of India has an increasing trend. India requires the involvement of all governments and other organizations to contribute to the cause of suicide awareness and prevention through activities, events, conferences and campaigns to solve this public health problem