Cranial and trunk neural crest cells use different mechanisms for attachment to extracellular matrices

We have used a quantitative cell attachment assay to compare the interactions of cranial and trunk neural crest cells with the extracellular matrix (ECM) molecules fibronectin, laminin and collagen types I and IV. Antibodies to the β_1 subunit of integrin inhibited attachment under all conditions tested, suggesting that integrins mediate neural crest cell interactions with these ECM molecules. The HNK-1 antibody against a surface carbohydrate epitope under certain conditions inhibited both cranial and trunk neural crest cell attachment to laminin, but not to fibronectin. An antiserum to α_1 intergrin inhibited attachment of trunk, but not cranial, neural crest cells to laminin and collagen type I, though interactions with fibronectin or collagen type IV were unaffected. The surface properties of trunk and cranial neural crest cells differed in several ways. First, trunk neural crest cells attached to collagen types I and IV, but cranial neural crest cells did not. Second, their divalent cation requirements for attachment to ECM molecules differed. For fibronectin substrata, trunk neural crest cells required divalent cations for attachment, whereas cranial neural crest cells bound in the absence of divalent cations. However, cranial neural crest cells lost this cation-independent attachment after a few days of culture. For laminin substrata, trunk cells used two integrins, one divalent cation-dependent and the other divalent cation-independent (Lallier, T. E. and Bronner-Fraser, M. (1991) Development 113, 1069–1081). In contrast, cranial neural crest cells attached to laminin using a single, divalent cation-dependent receptor system. Immunoprecipitations and immunoblots of surface labelled neural crest cells with HNK-1, α_1 integrin and β_1 integrin antibodies suggest that cranial and trunk neural crest cells possess biochemically distinct integrins. Our results demonstrate that cranial and trunk cells differ in their mechanisms of adhesion to selected ECM components, suggesting that they are non-overlapping populations of cells with regard to their adhesive properties

Protein misfolding in neurodegenerative diseases : implications and strategies

A hallmark of neurodegenerative proteinopathies is the formation of misfolded protein aggregates that cause cellular toxicity and contribute to cellular proteostatic collapse. Therapeutic options are currently being explored that target different steps in the production and processing of proteins implicated in neurodegenerative disease, including synthesis, chaperone-assisted folding and trafficking, and degradation via the proteasome and autophagy pathways. Other therapies, like mTOR inhibitors and activators of the heat shock response, can rebalance the entire proteostatic network. However, there are major challenges that impact the development of novel therapies, including incomplete knowledge of druggable disease targets and their mechanism of action as well as a lack of biomarkers to monitor disease progression and therapeutic response. A notable development is the creation of collaborative ecosystems that include patients, clinicians, basic and translational researchers, foundations and regulatory agencies to promote scientific rigor and clinical data to accelerate the development of therapies that prevent, reverse or delay the progression of neurodegenerative proteinopathies.Peer reviewe

Accelerating drug discovery for Alzheimer's disease: best practices for preclinical animal studies

Animal models have contributed significantly to our understanding of the underlying biological mechanisms of Alzheimer's disease (AD). As a result, over 300 interventions have been investigated and reported to mitigate pathological phenotypes or improve behavior in AD animal models or both. To date, however, very few of these findings have resulted in target validation in humans or successful translation to disease-modifying therapies. Challenges in translating preclinical studies to clinical trials include the inability of animal models to recapitulate the human disease, variations in breeding and colony maintenance, lack of standards in design, conduct and analysis of animal trials, and publication bias due to under-reporting of negative results in the scientific literature. The quality of animal model research on novel therapeutics can be improved by bringing the rigor of human clinical trials to animal studies. Research communities in several disease areas have developed recommendations for the conduct and reporting of preclinical studies in order to increase their validity, reproducibility, and predictive value. To address these issues in the AD community, the Alzheimer's Drug Discovery Foundation partnered with Charles River Discovery Services (Morrisville, NC, USA) and Cerebricon Ltd. (Kuopio, Finland) to convene an expert advisory panel of academic, industry, and government scientists to make recommendations on best practices for animal studies testing investigational AD therapies. The panel produced recommendations regarding the measurement, analysis, and reporting of relevant AD targets, th choice of animal model, quality control measures for breeding and colony maintenance, and preclinical animal study design. Major considerations to incorporate into preclinical study design include a priori hypotheses, pharmacokinetics-pharmacodynamics studies prior to proof-of-concept testing, biomarker measurements, sample size determination, and power analysis. The panel also recommended distinguishing between pilot 'exploratory' animal studies and more extensive 'therapeutic' studies to guide interpretation. Finally, the panel proposed infrastructure and resource development, such as the establishment of a public data repository in which both positive animal studies and negative ones could be reported. By promoting best practices, these recommendations can improve the methodological quality and predictive value of AD animal studies and make the translation to human clinical trials more efficient and reliable

Alien Registration- Leblanc, Gabrielle L. (Sanford, York County)

https://digitalmaine.com/alien_docs/2990/thumbnail.jp

Alien Registration- Leblanc, Gabrielle L. (Sanford, York County)

https://digitalmaine.com/alien_docs/2990/thumbnail.jp

Differential Development of Cholinergic Neurons from Cranial and Trunk Neural Crest Cells in Vitro

Several studies have suggested that the development of cholinergic properties in cranial parasympathetic neurons is determined by these cells' axial level of origin in the neural crest. All cranial parasympathetic neurons normally derive from cranial neural crest. Trunk neural crest cells give rise to sympathetic neurons, most of which are noradrenergic. To determine if there is an intrinsic difference in the ability of cranial and trunk neural crest cells to form cholinergic neurons, we have compared the development of choline acetyltransferase (ChAT)-immunoreactive cells in explants of quail cranial and trunk neural crest in vitro. Both cranial and trunk neural crest explants gave rise to ChAT-immunoreactive cells in vitro. In both types of cultures, some of the ChAT-positive cells also expressed immunoreactivity for the catecholamine synthetic enzyme tyrosine hydroxylase. However, several differences were seen between cranial and trunk cultures. First, ChAT-immunoreactive cells appeared two days earlier in cranial than in trunk cultures. Second, cranial cultures contained a higher proportion of ChAT-immunoreactive cells. Finally, a subpopulation of the ChAT-immunoreactive cells in cranial cultures exhibited neuronal traits, including neurofilament immunoreactivity. In contrast, neurofilament-immunoreactive cells were not seen in trunk cultures. These results suggest that premigratory cranial and trunk neural crest cells differ in their ability to form cholinergic neurons

Cognitive Function and Salivary DHEA Levels in Physically Active Elderly African American Women

Serum and plasma dehydroepiandrosterone sulfate (DHEAS) concentration has been associated with several health parameters associated with aging including cognitive function, bone mineral density, and muscular strength. However, the effectiveness of salivary DHEA for the prediction of cognitive function, bone mineral density, and muscular strength in older adults is currently unknown. Thirty elderly African American females provided early morning salivary samples and DHEA levels were determined using a commercially available immunoassay. Participants completed testing for psychomotor and executive function via Trail Making Tests (TMT) A and B, respectively. Bone ultrasound attenuation (BUA) was used to bone density and an isometric mid-thigh pull (IMTP) was used to determine isometric strength. Age significantly correlated with time on TMT A (r=0.328) and B (r=0.615) but was not related to DHEA, BUA, or IMTP outcomes. Elevated DHEA was associated with longer time to completion for TMT A (χ2=5.14) but not to TMT B. DHEA levels were not associated with BUA or IMTP outcomes. While elevated levels of DHEA were correlated with impaired psychomotor function, salivary DHEA is not associated with executive function, bone mineral density, or isometric strength in elderly African American women

'Transgender Education for Affirmative and Competent HIV and Healthcare (TEACHH)': protocol of community-based intervention development and a non-randomised multisite pilot study with pre-post test design in Canada

Introduction: Educational workshops are a promising strategy to increase healthcare providers’ ability to provide gender-affirming care for transgender (trans) people. This strategy may also reduce healthcare providers’ stigma towards trans people and people living with HIV. There is less evidence, however, of educational workshops that address HIV prevention and care among trans women. This protocol details development and pilot testing of the Transgender Education for Affirmative and Competent HIV and Healthcare intervention that aims to increase gender-affirming HIV care knowledge and perceived competency, and to reduce negative attitudes/biases, among providers. Methods and analysis: This community-based research (CBR) project involves intervention development and implementation of a non-randomised multisite pilot study with pre–post test design. First, we conducted a qualitative formative phase involving focus groups with 30 trans women and individual interviews with 12 providers to understand HIV care access barriers for trans women and elicit feedback on a proposed workshop. Second, we will pilot test the intervention with 90–150 providers (n=30–50×3 in-person settings). For pilot studies, primary outcomes include feasibility (eg, completion rate) and acceptability (eg, workshop satisfaction). Secondary preintervention and postintervention outcomes, assessed directly preceding and following the workshop, include perceived competency, attitudes/biases towards trans women with HIV, and knowledge needed to provide gender-affirming HIV care. Primary outcomes will be summarised as frequencies and proportions (categorical variables). We will conduct paired-sample t-tests to explore the direction of preintervention and postintervention differences for secondary outcomes. Ethics and dissemination: This study has been approved by the University of Toronto HIV Research Ethics Board (Protocol Number: 00036238). Study findings will be disseminated through community forums with trans women and service providers; manuscripts submitted to peer reviewed journals; and conferences. Findings will inform a larger CBR research agenda to remove barriers to engagement in HIV prevention/care among trans women across Canada.This work was supported by a Canadian Institutes of Health Research (CIHR) CBR Catalyst grant (2017). The work was also supported by the CIHR Clinical Trials Network (CTN 317). TEACHH development activities were also supported by CHL’s Ontario Ministry of Research & Innovation Early Researcher Award, Canada Foundation for Innovation grant, and the Canada Research Chairs Program. AIS was supported by a CIHR Fellowshi