Upregulation of cathepsin D in the caudate nucleus of primates with experimental parkinsonism

<p>Abstract</p> <p>Background</p> <p>In Parkinson's disease there is progressive loss of dopamine containing neurons in the substantia nigra pars compacta. The neuronal damage is not limited to the substantia nigra but progresses to other regions of brain, leading to loss of motor control as well as cognitive abnormalities. The purpose of this study was to examine causes of progressive damage in the caudate nucleus, which plays a major role in motor coordination and cognition, in experimental Parkinson's disease.</p> <p>Results</p> <p>Using chronic 1-methyl-4phenyl-1,2,3,6-tetrahydropyridine treatment of rhesus monkeys to model Parkinson's disease, we found a upregulation of Cathepsin D, a lysosomal aspartic protease, in the caudate nucleus of treated monkeys. Immunofluorescence analysis of caudate nucleus brain tissue showed that the number of lysosomes increased concurrently with the increase in Cathepsin D in neurons. <it>In vitro </it>overexpression of Cathepsin D in a human neuroblastoma cell line led to a significant increase in the number of the lysosomes. Such expression also resulted in extralysosomal Cathepsin D and was accompanied by significant neuronal death associated with caspase activation. We examined apoptotic markers and found a strong correlation of Cathepsin D overexpression to apoptosis.</p> <p>Conclusions</p> <p>Following damage to the substantia nigra resulting in experimental Parkinson's disease, we have identified pathological changes in the caudate nucleus, a likely site of changes leading to the progression of disease. Cathepsin D, implicated in pathogenic mechanisms in other disorders, was increased, and our <it>in vitro </it>studies revealed its overexpression leads to cellular damage and death. This work provides important clues to the progression of Parkinson's, and provides a new target for strategies to ameliorate the progression of this disease.</p

A Circular Pedagogy for Higher Education

Over the last two decades, higher education has been subject to significant scrutiny due to increasing pressures to provide a meaningful and relevant learning experience to the student population, and by their strong connection to the functioning of the economic and political systems. By reflecting on the controversies surrounding pedagogy, this paper contributes to the current debate by exploring pedagogy as a circular process where learners grow and develop by taking different roles and identities as they navigate a research-informed learning continuum defined by growing levels of complexity and uncertainty. This study introduces a new pedagogical paradigm for adult education, inspired by the Humboldtian model for higher education and that we have coined as “circular pedagogy” where the role of the teacher, student and researcher are indissoluble

Circular Pedagogy for Smart, Inclusive and Sustainable Education

Higher education institutions seem to be engaged in a reactive process when thinking about education for sustainable development, instead of being proactive. A every stage, educational models remain very limited to specific goals and agendas driven by the fad of the moment and without articulating a sustainable educational model that we argue should be uttered within the concepts of intercultural competencies, smart, inclusive, and sustainable education where learners engage on a circular learning process as captured by the circular pedagogy for higher education. If the academic community is serious about driving actions that help us to enact change and impact to develop a more sustainable conscious socio-economic and environmental global society, we need to rethink our education models and pedagogies so that they are attuned with the complexity of our evolving reality

Coxsackievirus B3 Inhibits Antigen Presentation In Vivo, Exerting a Profound and Selective Effect on the MHC Class I Pathway

Many viruses encode proteins whose major function is to evade or disable the host T cell response. Nevertheless, most viruses are readily detected by host T cells, and induce relatively strong T cell responses. Herein, we employ transgenic CD4+ and CD8+ T cells as sensors to evaluate in vitro and in vivo antigen presentation by coxsackievirus B3 (CVB3), and we show that this virus almost completely inhibits antigen presentation via the MHC class I pathway, thereby evading CD8+ T cell immunity. In contrast, the presentation of CVB3-encoded MHC class II epitopes is relatively unencumbered, and CVB3 induces in vivo CD4+ T cell responses that are, by several criteria, phenotypically normal. The cells display an effector phenotype and mature into multi-functional CVB3-specific memory CD4+ T cells that expand dramatically following challenge infection and rapidly differentiate into secondary effector cells capable of secreting multiple cytokines. Our findings have implications for the efficiency of antigen cross-presentation during coxsackievirus infection

The adaptive potential of the M-domain of yeast Hsp90 [preprint]

Comparing the distribution of fitness effects (DFE) of new mutations across different environments quantifies the potential for adaptation in a given environment and its cost in other environments. So far, results regarding the cost of adaptation across environments have been mixed, and there were no sufficiently large data sets to map its variation along the genome. Here, we study the DFEs of ≈2500 amino-acid changing mutations obtained from deep mutational scanning of the 118 amino-acid-long middle domain of the heat-shock protein Hsp90 in five environments and at two expression levels. This region is known to be important for client binding, stabilization of the Hsp90 dimer, stabilization of the N-M and M-C interdomains and regulation of ATPase-chaperone activity. Despite the diverse and stressful environments, we find that fitness correlates well across environments, with the exception of one environment, diamide. Consistent with these results, we find very little cost of adaptation; on average only one in seven beneficial mutations is deleterious in another environment. We identify a hotspot of beneficial mutations in a region of the protein that is located within an allosteric center. The identified protein regions that are enriched in beneficial, deleterious, and costly mutations coincide with residues that are involved in the stabilization of Hsp90 interdomains and stabilization of client binding interfaces or residues that are involved in ATPase chaperone activity of Hsp90. Thus, our study yields information regarding the role and adaptive potential of a protein sequence that complements and extends known structural information

The Adaptive Potential of the Middle Domain of Yeast Hsp90

The distribution of fitness effects (DFEs) of new mutations across different environments quantifies the potential for adaptation in a given environment and its cost in others. So far, results regarding the cost of adaptation across environments have been mixed, and most studies have sampled random mutations across different genes. Here, we quantify systematically how costs of adaptation vary along a large stretch of protein sequence by studying the distribution of fitness effects of the same approximately 2,300 amino-acid changing mutations obtained from deep mutational scanning of 119 amino acids in the middle domain of the heat shock protein Hsp90 in five environments. This region is known to be important for client binding, stabilization of the Hsp90 dimer, stabilization of the N-terminal-Middle and Middle-C-terminal interdomains, and regulation of ATPase-chaperone activity. Interestingly, we find that fitness correlates well across diverse stressful environments, with the exception of one environment, diamide. Consistent with this result, we find little cost of adaptation; on average only one in seven beneficial mutations is deleterious in another environment. We identify a hotspot of beneficial mutations in a region of the protein that is located within an allosteric center. The identified protein regions that are enriched in beneficial, deleterious, and costly mutations coincide with residues that are involved in the stabilization of Hsp90 interdomains and stabilization of client-binding interfaces, or residues that are involved in ATPase-chaperone activity of Hsp90. Thus, our study yields information regarding the role and adaptive potential of a protein sequence that complements and extends known structural information

Survival of High-Risk Pediatric Neuroblastoma Patients In a Developing Country

Little information is available about survival of high‐risk pediatric neuroblastoma patients in developing countries. We aimed to assess survival among high‐risk pediatric neuroblastoma patients in La Plata, Argentina. Individuals eligible for our cohort were aged4 yr at diagnosis, 54% were male, and 62% had adrenal neuroblastoma. We observed 18 deaths, and the median survival time of our study population was 1.7 yr. The five‐yr overall survival probability was 24% (95% CL: 10%, 41%). In contrast, five‐yr survival of high‐risk neuroblastoma patients ranges between 23% and 76% in developed countries. Survival among high‐risk neuroblastoma patients is generally poor regardless of geographic location, but our results illustrate dramatically worse survival for patients in a developing country. We speculate that the observed survival differences could be attenuated or eliminated with improvements in treatment and supportive care, but addressing these issues will require creative solutions because of resource limitations

Investigating the influence of environment on the evolution of Hsp90 using comprehensive fitness maps [preprint]

Gene-environment interactions have long been theorized to influence molecular evolution. However, the environmental dependence of most mutations remains unknown. Using deep mutational scanning, we engineered budding yeast with all 44,604 single codon changes encoding 14,160 amino acid variants in Hsp90 and quantified growth effects under standard laboratory conditions and under five stress conditions (elevated temperature, nitrogen starvation, elevated salinity, high ethanol concentration, and oxidative stress caused by diamide). To our knowledge these are the largest comprehensive fitness maps of point mutant growth effects that have been determined. The growth effects of many variants differed between each of the conditions, indicating that environmental conditions can have a large impact on the evolution of Hsp90. Multiple variants provided growth advantages relative to wildtype Hsp90 under individual conditions, however these variants tended to exhibit growth defects in other environments. The diversity of Hsp90 sequences observed in extant eukaryotes preferentially contain amino acid variants that supported robust growth under all tested conditions. Thus, rather than favoring substitutions in individual conditions, the long-term selective pressure on Hsp90 may have been that of fluctuating environments, leading to robustness under a variety of conditions

Circular Pedagogy to Advance the Integration of Learning Technologies: Supporting Technological Universities Cultural Transformation

European countries need active and proactive educational systems assisted by models that can drive a cultural transformation that supports sustainable socio-economic and environmental development. In this paper, we reflect on the future of European education. We offer some insights on how the foundations of a new educational model (ANEM) could be cemented and solidly supported by pillars that acknowledge our societies\u27 rich and diverse cultures. Furthermore, the European University of Technology\u27s (EUt+) future educational model is taken as a case study to enable us to reflect and analyse the need for novel pedagogies that drive change for a more sustainable socio-economic and environmentally friendly European society. European education faces significant challenges from the need to enable learning environments guided by equity, diversity, and inclusive frameworks for all categories. To make progress, it is essential that we first learn how new inclusive learning environments can be articulated to help us address our contemporary society\u27s learning needs and demands. We are conscious that education worldwide faces a stark and unpleasant reality as the students/learners\u27 learning experience is significantly impacted by social status and economic disparities. Students are often confronted with difficult situations involving racism, discrimination and exclusion that materialise in students suffering mistreatment and microaggressions in learning environments still blind to the biases forwarded through teaching practices. The richness of our European cultures and languages and their significance in helping us to work together are paramount in our quest for high-quality education that cultivates, promotes, and cherishes European educational values while welcoming other cultures and languages. Within the complexities of our global societies, we argue that the future of our educational system must enable and foster mechanisms that nurture behaviours that will help us address cultural conflict, clashes, and potential detachment. Cultural clashes emerge as a major challenge for the development of our future European University, and we need to be able to minimise potential problems associated with multicultural, plurilingual and diverse working and learning environments. We are conscious of the need to develop appropriate educational programmes and curricula guided by our novel Circular Pedagogy , where we provide an initial and evolving framework for students, teachers, and researchers to interchange their roles. We propose a learner-centred, dynamic, and proactive pedagogy that helps us to manage and navigate the inevitable cultural conflict and supports us in understanding and identifying the triggers that might arise due to cultural clashes and increasing levels of detachment

Draft genome sequences of gammaproteobacterial methanotrophs isolated from marine ecosystems

The genome sequences of Methylobacter marinus A45, Methylobacter sp. strain BBA5.1, and Methylomarinum vadi IT-4 were obtained. These aerobic methanotrophs are typical members of coastal and hydrothermal vent marine ecosystems