Optimisation and mechanistic insights of dyskinesia in rodent models of Parkinson's disease

The work presented in herein focuses on the optimisation and use of established animal models to study behavioural, pharmacological, histological and molecular correlates of the debilitating motor side effects of current and future treatments for Parkinson’s disease, namely L-DOPA induced dyskinesia (LID) and graft induced dyskinesia (GID). Chapter 3 optimises the 6-OHDA lesion model in mice, from surgical approaches to behavioural assessment of motor function. The neurotoxin was injected at three different regions along the nigrostriatal tract to produce unique patterns of dopaminergic cell death in the midbrain. The resulting cell loss was correlated to behavioural deficits identified through an extensive battery of motor hand tests. Fully lesioned mice from each of the three models were chosen for chronic L-DOPA treatment, described in Chapter 4, where doses were increased every 1-2 weeks. Behaviour was assessed and correlated to deficits on motor hand tests prior to L-DOPA treatment, cell loss within sub regions of the midbrain, serotonergic density levels and upregulations in ΔFosB and striatal TH cell populations. Chapter 5 uses knowledge gained in previous chapters to use the most appropriate 6-OHDA mouse model of LID for the examination of changes in the Regulators of G-protein Signalling (RGS) following an acute and chronic L-DOPA treatment. RGS2 was the only one to increase significantly following either treatment regime. In Chapter 6 a well established rat model of GID (the induction of dyskinesia in the transplanted 6-OHDA lesioned rat through the administration of amphetamine) was used to assess the use of pharmacological agents known to reduce LID. Changes in locomotor function and abnormal inhibitory movements (AIMs) could be assessed giving an insight into the mechanism and receptors involved. To further the understanding of GID, Chapter 7 examines dopamine receptor levels, RGS transcript expression, and the proportions of dopamine and serotonin cells in the transplanted, 6-OHDA lesioned rodent brain. The aim was to determine any correlation between these parameters and amphetamine induced dyskinesia. Only the number of dopaminergic and serotonin cells could be correlated to dyskinesia and not the proportion of serotonin cells. As no previous mouse model of GID has been established, Chapter 8 demonstrates that transplantation of E12 ventral mesencephalon (VM) grafts can be optimised in the lesioned mouse of C57/Bl6 and CD1 strains to give functional recovery, and amphetamine induced dyskinesia. Both strains were also used to demonstrate that transplants were also able to reduce LID.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Optimisation and mechanistic insights of dyskinesia in rodent models of Parkinson’s disease

The work presented in herein focuses on the optimisation and use of established animal models to study behavioural, pharmacological, histological and molecular correlates of the debilitating motor side effects of current and future treatments for Parkinson’s disease, namely L-DOPA induced dyskinesia (LID) and graft induced dyskinesia (GID). Chapter 3 optimises the 6-OHDA lesion model in mice, from surgical approaches to behavioural assessment of motor function. The neurotoxin was injected at three different regions along the nigrostriatal tract to produce unique patterns of dopaminergic cell death in the midbrain. The resulting cell loss was correlated to behavioural deficits identified through an extensive battery of motor hand tests. Fully lesioned mice from each of the three models were chosen for chronic L-DOPA treatment, described in Chapter 4, where doses were increased every 1-2 weeks. Behaviour was assessed and correlated to deficits on motor hand tests prior to L-DOPA treatment, cell loss within sub regions of the midbrain, serotonergic density levels and upregulations in ΔFosB and striatal TH cell populations. Chapter 5 uses knowledge gained in previous chapters to use the most appropriate 6-OHDA mouse model of LID for the examination of changes in the Regulators of G-protein Signalling (RGS) following an acute and chronic L-DOPA treatment. RGS2 was the only one to increase significantly following either treatment regime. In Chapter 6 a well established rat model of GID (the induction of dyskinesia in the transplanted 6-OHDA lesioned rat through the administration of amphetamine) was used to assess the use of pharmacological agents known to reduce LID. Changes in locomotor function and abnormal inhibitory movements (AIMs) could be assessed giving an insight into the mechanism and receptors involved. To further the understanding of GID, Chapter 7 examines dopamine receptor levels, RGS transcript expression, and the proportions of dopamine and serotonin cells in the transplanted, 6-OHDA lesioned rodent brain. The aim was to determine any correlation between these parameters and amphetamine induced dyskinesia. Only the number of dopaminergic and serotonin cells could be correlated to dyskinesia and not the proportion of serotonin cells. As no previous mouse model of GID has been established, Chapter 8 demonstrates that transplantation of E12 ventral mesencephalon (VM) grafts can be optimised in the lesioned mouse of C57/Bl6 and CD1 strains to give functional recovery, and amphetamine induced dyskinesia. Both strains were also used to demonstrate that transplants were also able to reduce LID

Influence of chronic L-DOPA treatment on immune response following allogeneic and xenogeneic graft in a rat model of Parkinson's disease

Although intrastriatal transplantation of fetal cells for the treatment of Parkinson’s disease had shown encouraging results in initial open-label clinical trials, subsequent double-blind studies reported more debatable outcomes. These studies highlighted the need for greater preclinical analysis of the parameters that may influence the success of cell therapy. While much of this has focused on the cells and location of the transplants, few have attempted to replicate potentially critical patient centered factors. Of particular relevance is that patients will be under continued L-DOPA treatment prior to and following transplantation, and that typically the grafts will not be immunologically compatible with the host. The aim of this study was therefore to determine the effect of chronic L-DOPA administered during different phases of the transplantation process on the survival and function of grafts with differing degrees of immunological compatibility. To that end, unilaterally 6-OHDA lesioned rats received sham surgery, allogeneic or xenogeneic transplants, while being treated with L-DOPA before and/or after transplantation. Irrespective of the L-DOPA treatment, dopaminergic grafts improved function and reduced the onset of L-DOPA induced dyskinesia. Importantly, although L-DOPA administered post transplantation was found to have no detrimental effect on graft survival, it did significantly promote the immune response around xenogeneic transplants, despite the administration of immunosuppressive treatment (cyclosporine). This study is the first to systematically examine the effect of L-DOPA on graft tolerance, which is dependent on the donor-host compatibility. These findings emphasize the importance of using animal models that adequately represent the patient paradigm

Monitoring canid scent marking in space and time using a biologging and machine learning approach

For canid species, scent marking plays a critical role in territoriality, social dynamics, and reproduction. However, due in part to human dependence on vision as our primary sensory modality, research on olfactory communication is hampered by a lack of tractable methods. In this study, we leverage a powerful biologging approach, using accelerometers in concert with GPS loggers to monitor and describe scent-marking events in time and space. We performed a validation experiment with domestic dogs, monitoring them by video concurrently with the novel biologging approach. We attached an accelerometer to the pelvis of 31 dogs (19 males and 12 females), detecting raised-leg and squat posture urinations by monitoring the change in device orientation. We then deployed this technique to describe the scent marking activity of 3 guardian dogs as they defend livestock from coyote depredation in California, providing an example use-case for the technique. During validation, the algorithm correctly classifed 92% of accelerometer readings. High performance was partly due to the conspicuous signatures of archetypal raised-leg postures in the accelerometer data. Accuracy did not vary with the weight, age, and sex of the dogs, resulting in a method that is broadly applicable across canid species’ morphologies. We also used models trained on each individual to detect scent marking of others to emulate the use of captive surrogates for model training. We observed no relationship between the similarity in body weight between the dog pairs and the overall accuracy of predictions, although models performed best when trained and tested on the same individual. We discuss how existing methods in the feld of movement ecology can be extended to use this exciting new data type. This paper represents an important frst step in opening new avenues of research by leveraging the power of modern-technologies and machine-learning to this feldFil: Bidder, Owen. University of California at Berkeley; Estados UnidosFil: Di Virgilio, Agustina Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Hunter, Jennifer. University of California at Berkeley; Estados UnidosFil: McInturff, Alex. University of California at Berkeley; Estados UnidosFil: Gaynor, Kaitlyn. University of California at Berkeley; Estados UnidosFil: Smith, Alison. University of California at Berkeley; Estados UnidosFil: Dorcy, Janelle. University of California at Berkeley; Estados UnidosFil: Rosell, Frank. University of South-Eastern Norway; Norueg

How neurons maintain their axons long-term: an integrated view of axon biology and pathology

Axons are processes of neurons, up to a metre long, that form the essential biological cables wiring nervous systems. They must survive, often far away from their cell bodies and up to a century in humans. This requires self-sufficient cell biology including structural proteins, organelles, and membrane trafficking, metabolic, signalling, translational, chaperone, and degradation machinery—all maintaining the homeostasis of energy, lipids, proteins, and signalling networks including reactive oxygen species and calcium. Axon maintenance also involves specialised cytoskeleton including the cortical actin-spectrin corset, and bundles of microtubules that provide the highways for motor-driven transport of components and organelles for virtually all the above-mentioned processes. Here, we aim to provide a conceptual overview of key aspects of axon biology and physiology, and the homeostatic networks they form. This homeostasis can be derailed, causing axonopathies through processes of ageing, trauma, poisoning, inflammation or genetic mutations. To illustrate which malfunctions of organelles or cell biological processes can lead to axonopathies, we focus on axonopathy-linked subcellular defects caused by genetic mutations. Based on these descriptions and backed up by our comprehensive data mining of genes linked to neural disorders, we describe the ‘dependency cycle of local axon homeostasis’ as an integrative model to explain why very different causes can trigger very similar axonopathies, providing new ideas that can drive the quest for strategies able to battle these devastating diseases

Autophagic and endo-lysosomal dysfunction in neurodegenerative disease

Due to their post-mitotic state, metabolic demands and often large polarised morphology, the function and survival of neurons is dependent on an efficient cellular waste clearance system both for generation of materials for metabolic processes and removal of toxic components. It is not surprising therefore that deficits in protein clearance can tip the balance between neuronal health and death. Here we discuss how autophagy and lysosome-mediated degradation pathways are disrupted in several neurological disorders. Both genetic and cell biological evidence show the diversity and complexity of vesicular clearance dysregulation in cells, and together may ultimately suggest a unified mechanism for neuronal demise in degenerative conditions. Causative and risk-associated mutations in Alzheimer’s disease, Frontotemporal Dementia, Amyotrophic Lateral Sclerosis, Parkinson’s disease, Huntington’s disease and others have given the field a unique mechanistic insight into protein clearance processes in neurons. Through their broad implication in neurodegenerative diseases, molecules involved in these genetic pathways, in particular those involved in autophagy, are emerging as appealing therapeutic targets for intervention in neurodegeneration

Identification of clusters of individuals relevant to temporomandibular disorders and other chronic pain conditions: the OPPERA study

The classification of most chronic pain disorders gives emphasis to anatomical location of the pain to distinguish one disorder from the other (eg, back pain vs temporomandibular disorder [TMD]) or to define subtypes (eg, TMD myalgia vs arthralgia). However, anatomical criteria overlook etiology, potentially hampering treatment decisions. This study identified clusters of individuals using a comprehensive array of biopsychosocial measures. Data were collected from a case–control study of 1031 chronic TMD cases and 3247 TMD-free controls. Three subgroups were identified using supervised cluster analysis (referred to as the adaptive, pain-sensitive, and global symptoms clusters). Compared with the adaptive cluster, participants in the pain-sensitive cluster showed heightened sensitivity to experimental pain, and participants in the global symptoms cluster showed both greater pain sensitivity and greater psychological distress. Cluster membership was strongly associated with chronic TMD: 91.5% of TMD cases belonged to the pain-sensitive and global symptoms clusters, whereas 41.2% of controls belonged to the adaptive cluster. Temporomandibular disorder cases in the pain-sensitive and global symptoms clusters also showed greater pain intensity, jaw functional limitation, and more comorbid pain conditions. Similar results were obtained when the same methodology was applied to a smaller case–control study consisting of 199 chronic TMD cases and 201 TMD-free controls. During a median 3-year follow-up period of TMD-free individuals, participants in the global symptoms cluster had greater risk of developing first-onset TMD (hazard ratio = 2.8) compared with participants in the other 2 clusters. Cross-cohort predictive modeling was used to demonstrate the reliability of the clusters

Genomic resources for Myzus persicae: EST sequencing, SNP identification, and microarray design

<p>Abstract</p> <p>Background</p> <p>The green peach aphid, <it>Myzus persicae </it>(Sulzer), is a world-wide insect pest capable of infesting more than 40 plant families, including many crop species. However, despite the significant damage inflicted by <it>M. persicae </it>in agricultural systems through direct feeding damage and by its ability to transmit plant viruses, limited genomic information is available for this species.</p> <p>Results</p> <p>Sequencing of 16 <it>M. persicae </it>cDNA libraries generated 26,669 expressed sequence tags (ESTs). Aphids for library construction were raised on <it>Arabidopsis thaliana</it>, <it>Nicotiana benthamiana</it>, <it>Brassica oleracea, B. napus</it>, and <it>Physalis floridana </it>(with and without <it>Potato leafroll virus </it>infection). The <it>M. persicae </it>cDNA libraries include ones made from sexual and asexual whole aphids, guts, heads, and salivary glands. <it>In silico </it>comparison of cDNA libraries identified aphid genes with tissue-specific expression patterns, and gene expression that is induced by feeding on <it>Nicotiana benthamiana</it>. Furthermore, 2423 genes that are novel to science and potentially aphid-specific were identified. Comparison of cDNA data from three aphid lineages identified single nucleotide polymorphisms that can be used as genetic markers and, in some cases, may represent functional differences in the protein products. In particular, non-conservative amino acid substitutions in a highly expressed gut protease may be of adaptive significance for <it>M. persicae </it>feeding on different host plants. The Agilent eArray platform was used to design an <it>M. persicae </it>oligonucleotide microarray representing over 10,000 unique genes.</p> <p>Conclusion</p> <p>New genomic resources have been developed for <it>M. persicae</it>, an agriculturally important insect pest. These include previously unknown sequence data, a collection of expressed genes, molecular markers, and a DNA microarray that can be used to study aphid gene expression. These resources will help elucidate the adaptations that allow <it>M. persicae </it>to develop compatible interactions with its host plants, complementing ongoing work illuminating plant molecular responses to phloem-feeding insects.</p