This thesis explores the proposal that there is a close link between counterfactual thinking and lying. Although both require the imagination of alternatives to reality, research has yet to establish a direct link. In the first seven studies the relationship between counterfactuals and lies is directly investigated using novel scenario-based and behavioural tasks. In a further four studies we also investigate the role of affect and executive functions as explanatory mechanisms. Results show that individuals with a tendency to think counterfactually are more likely to generate potential lies and to be more successful when lying in front of others (Study 1 and 6). Furthermore, we also show that counterfactual availability influences people’s tendency to come up with lies (Studies 2, and 3) and the extent to which they expect others to lie (Studies 4, and 5). We also find that the saliency of counterfactual alternatives can affect people’s moral standards by motivating them to lie (Study 7). Based on these results we argue that counterfactuals motivate lying by providing information about how things could have been different. We however also investigate alternative explanations. In Studies 8, 9 and 10 we seek to understand whether counterfactually derived affect might also underlie the relationship, but find no such link. Additionally, in Study 11 we investigate the relationship in Parkinson’s disease participants in order to understand if executive function might be an underlying mechanism. We do not find this to be the case and we show that PD patients are able to engage in counterfactual thinking and also lie. The findings in this thesis are the first to provide a direct link between counterfactual thoughts and lies. Overall, we show how counterfactuals can help us mislead others and we reveal that counterfactual thinking is an important cognitive process in deception.

G-substrate is a 23 kDa protein named as a specific substrate of cGMP-dependent protein kinase and found predominantly in cerebellar Purkinje cells. As a component of the NO/cGMP/PKG pathway, G-substrate is potentially involved in several important cellular processes and has so far been associated with a number of disease conditions: a single point mutation in G-substrate has been linked to hypercholesterolaemia, while the potent inhibition of PP2A by phosphorylated Gsubstrate possibly influences Tau protein hyperphosphorylation and contributes to Alzheimer's disease pathology. Conversely, overexpression of G-substrate protein in dopaminergic neurons has been found to protect neurons from Parkinson's disease toxins, making G-substrate a possible target of interventions for mitigating the debilitating effects of Parkinson's disease on patients. A shorter splice variant, which only retains one of the phosphorylatable threonine motifs, has recently been described for G-substrate and given the importance of phosphorylation to its action as a phosphatase inhibitor, this study focuses on determining whether both variants of the protein exhibit similar levels of phosphatase inhibition and interact with the same/similar proteins in vivo. We were also interested in determining whether the 51 amino acid section absent from short G-substrate resulted in any significant differences in protein structure, which potentially has implications on functions in vivo. My results indicate the association of G-substrate with a wide range of proteins involved in processes including cell cycle regulation, endocytosis and signalling and the two variants do not always interact with the same proteins. Among these interactors is the PARK 7/ DJ-1 protease, which like G-substrate has been shown to be neuroprotective. I have found that G-substrate is proteolysed by DJ-1 in its active form and interactions between these two proteins is affected by the anti-vertigo drug Tanganil. Phosphatase inhibition studies suggest that the G-substrate variants affect phosphatase activity to different extents under similar conditions, while NMR and circular dichroism structural studies suggest that in solution, the full length Gsubstrate variant is slightly more compactly folded. Understanding the details of G-substrate action in the cell will lead to a better understanding of its roles including the protection of dopaminergic neurons from Parkinson's disease toxins and shed more light on the intricacies of the NO/cGMP/PKG signalling pathway as a whole, thus providing important information that might help improve strategies for dealing with conditions involving this pathway and help develop interventions for diseases such as Alzheimer's and Parkinson's.

Background: Parkinson's disease (PD) is a chronic, progressive, neurodegenerative disorder with currently no known cure. PD has a significant impact on quality of life of the patients, as well as, the caregivers and family members. It is the second most common cause of chronic neurological disability in US and Europe. According to National Parkinson's Foundation, there are almost 1 million patients in the Unites States and 50,000 to 60,000 new cases of PD are diagnosed each year. The total number of cases of PD is predicted to double by 2030. The annual cost associated with this disease is estimated to be $10.8 billion in the United States, including the cost of treatment and the cost of the disability. Although it is primarily thought of as a movement-disorder and is clinically diagnosed based on motor symptoms, non-motor symptoms such as cognitive and emotional deficits are thought to precede the clinical diagnosis by almost 20 years. By the time of clinical diagnosis, there is 80% loss in the dopamine content in the striatum and 50% degeneration of the substantia nigra dopamine cells. The research presented in this thesis was an attempt to develop an animal model of PD in its pre-motor stages. Such a model would allow us to develop pre-clinical markers for PD, and facilitate the development and testing of potential treatment strategies for the non-motor symptoms of the disorder. Specific Aims: There were five specific aims for this research: * The first specific aim dealt with development of a rat model of PD with slow, progressive onset of motor deficits, determination of timeline for future studies, and quantification the dopamine depletion in this model at a pre-motor stage. * The second and the third specific aims focused on testing for emotional (aversion) deficits and cognitive (executive functioning) deficits in this rat model at the 3 week timepoint determined during specific aim 1. * The fourth specific aim was to determine the brain network changes associated with the behavioral changes observed our rat model using resting state connectivity as a measure. * The fifth and the final specific aim was to test sodium butyrate, a drug from the histone deacetylase inhibitor family, as a potential treatment option for cognitive deficits in PD. Results: The 6-hydroxy dopamine based stepwise striatal lesion model of pre-motor PD, developed during this research, exhibits delayed onset of Parkinsonian gait like symptoms by week 4 after the lesions. At 3 weeks post lesion (3WKPD), the rats exhibit 27% reduction in striatal dopamine and 23%reduction in substantia nigra dopamine cells, with lack of any apparent motor deficits. The 3WKPD rats also exhibited changes in aversion. The fMRI study with the aversive scent pointed towards possible amygdala dysfunction sub-serving the aversion deficits. The executive function deficits tested using a rat analog of the Wisconsin card sorting test, divulged an extra-dimensional set shifting deficit in the 3WKPD rats similar to those reported in PD patients. The resting state connectivity study indicated significant changes in the 3WKPD rats compared to age matched controls. We observed increased overall connectivity of the motor cortex and increased CPu connectivity with prefrontal cortex, cingulate cortex, and hypothalamus in the 3WKPD rats compared to the controls. These observations parallel the observations in unmedicated early-stage PD patients. We also observed negative correlation between amygdala and prefrontal cortex as reported in humans. This negative correlation was lost in 3WKPD rats. Sodium butyrate treatment, tested in the cognitive deficit study, was able to ameliorate the extra-dimensional set shifting deficit observed in this model. This treatment also improved the attentional set formation. Conclusion: Taken together, our observations indicate that, the model of pre-motor stage PD developed during this research is a very high face validity rat model of late Braak stage 2 or early Braak stage 3 PD. Sodium butyrate was able to alleviate the cognitive deficits observed in our rat model. Hence, along with the prior reports of anti-depressant and neuroprotective effects of this drug, our results point towards a possible treatment strategy for the non-motor deficits of PD.

Introdução: A Doença de Parkinson (DP) é a segunda doença neurodegenerativa mais comum. Os sintomas motores são decorrentes da morte de neurônios dopaminérgicos da Substância Nigra mesencefálica e por inclusões intracitoplasmáticas de ?-sinucleína, os corpúsculos de Lewy (CL). A doença pode ser o resultado de fatores ambientais agindo sobre um indivíduo geneticamente susceptível. O objetivo desse estudo foi verificar a frequência de mutações no gene PARK8/LRRK2 em uma amostra de pacientes brasileiros portadores de DP e descrever as principais correlações clínicas encontradas nos pacientes com mutações. Metodologia: Estudo transversal baseado no protocolo padronizado pelo projeto LARGE-PD (Latin American Research Consortium on The Genetics of PD) aplicado em 282 pacientes com DP recrutados de ambulatórios especializados em Distúrbios do Movimento do Hospital das Clínicas de Ribeirão Preto/USP e do Hospital São Paulo/UNIFESP, entre os anos de 2007 e 2014. O material genético colhido foi enviado para Seattle, com análise genética realizada no laboratório do Dr. Cyrus Zabetian da Universidade de Washington. Resultados: Realizado pesquisa genética para o LRRK2 em 229 pacientes de 282 pacientes que preencheram o protocolo. Quatro (1,74%) pacientes foram positivos para a mutação. Nos casos de inicio precoce, a frequência foi de apenas um caso (2,43% - 1/41). Três pacientes tinham história familiar positiva para DP (3,7% - 3/81). A idade de inicio dos sintomas variou entre 38 e 55 anos. A mutação G2019S esteve presente em 1,31% (3/229). Foi encontrado também um caso de mutação para R1441C. Conclusões: O LRRK2 se mostrou um importante gene correlacionado a DP, tendo como principal mutação a G2019S. O início dos sintomas variou entre 38 e 55 anos, sempre unilateral, com boa resposta a Levodopa. / Introduction: Parkinson\'s disease (PD) is the second most common neurodegenerative disease. Motor symptoms are due to the death of dopaminergic neurons in the midbrain Substance Nigra and intracytoplasmic inclusions known as Lewy bodies (CL), rich in a protein called ?-synuclein. The disease can be the result of environmental factors acting on an individual genetically susceptible, multifactorial etiology. The aim of this study was to determine the frequency of mutations in the gene PARK8 / LRRK2 in a sample of brazilian patients with PD and describe the main clinical correlations in patients with mutations. Methodology: This is a crosssectional study based on a standardized protocol for LARGE-PD project (Latin American Research Consortium on The Genetics of PD) applied in 282 patients with PD recruited from specialized clinics in Movement Disorders seen at Hospital das Clínicas de Ribeirão Preto/USP and Hospital São Paulo/UNIFESP, between the years 2007 and 2014. The genetic material was sent to Seattle, and genetic analysis was performed in the laboratory of Dr. Cyrus Zabetian at the University of Washington. Results: Realized genetic research for LRRK2 in 229 patients of 282 patients who met the LARGE-PD protocol. Observed four (1,74%) patients positive for the mutation. In cases of early-onset, the frequency was only one case (2,43% - 1/41). Three patients had a family history of PD (3,7% - 3/81). The age of onset of symptoms in patients with mutations varied between 38 and 55 years. A total of PD patients with the DNA analyzed, G2019S was present in 1,31% (3/229). It was also found one case to mutation R1441C. Conclusions: The LRRK2 had great influence gene correlated with PD, the main mutation G2019S. The onset of symptoms varied between 38 and 55 years, always one-sided, with good response to levodopa.

No description available.

Hypokinetic dysarthria is a speech disorder that commonly occurs in individuals with Parkinson’s disease (PD). However, little is known about the speech characteristics and the effects of speech treatment on the speech of Mandarin speakers with hypokinetic dysarthria (henceforth, Mandarin speakers with PD). The purpose of this dissertation was to investigate the effects of intensive voice treatment on the speech intelligibility and acoustics of this population. This dissertation consisted of three papers. The first paper, “Acoustic and perceptual speech characteristics of native Mandarin speakers with Parkinson’s disease,” investigated the general speech characteristics of 11 Mandarin speakers with PD. Intelligibility and acoustic outcomes were reported and compared to seven age- and gender-matched neurologically healthy controls. Findings from this study showed that Mandarin speakers with PD exhibited decreased intelligibility, local pitch variation, vowel space area, speech rate, and rate variation. The second paper, “Effects of Loudness and Rate Manipulation Strategies on Speech Intelligibility and Acoustics of Mandarin Speakers With Parkinson’s Disease,” examined the effects of cueing to increase loudness and reduce speech rate on speech intelligibility and acoustics. Acoustic features including speech intensity, pitch range, pause duration, pause frequency, articulation rate, and vowel space area across 11 Mandarin speakers with PD were analyzed. The relationship between speech intelligibility and acoustic features was reported. Results showed that cueing for loud speech significantly increased intelligibility, but cueing for slow speech did not. Different cues had differential effects on the selected acoustic features. Cueing for loud speech resulted in increased vocal intensity and cueing for slow speech resulted in reduced articulation rate and increased pause frequency. In the loud speaking condition, greater vocal intensity and larger vowel space contributed to increased intelligibility, whereas in the slow condition, increased intensity, vowel space, as well as articulation rate, showed a trend toward contributing to increased intelligibility. The third paper, “The Effects of Intensive Voice Treatment on Intelligibility in Mandarin Speakers with Parkinson’s Disease: Acoustic and perceptual findings,” investigated the short- and long-term effects of intensive voice treatment (Lee Silverman Voice Treatment LOUD) on speech intelligibility and acoustics of nine Mandarin speakers with PD. All speakers showed increased intelligibility from pretreatment to immediate post-treatment, and the improvement was maintained at the 6-month follow-up. Five acoustic features were analyzed. Speech intensity, vowel space, and speech rate changed significantly in positive directions immediately post-treatment, and the increases were retained up to six months. Global pitch variation increased immediately post-treatment but not at the 6-month follow-up. No changes were found in local pitch variation following treatment. Self-reported intelligibility, voice quality, confidence, frustration level, and communicative participation changed positively immediately after the completion of treatment and at the 6-month follow-up. To conclude, the speech characteristics of Mandarin speakers with PD were generally consistent with those of English speakers with PD, except that speech was slower in the Mandarin speakers. Cueing to increase loudness and reduce rate had different effects on speech intelligibility and production, with louder speech yielding greater intelligibility and acoustic benefits. Following intensive voice treatment (LSVT LOUD), Mandarin speakers with PD increased their vocal intensity. Speech intelligibility, vowel space, global pitch variation and speech rate increased as a result of the treatment. Thus, some differences between Mandarin and English dysarthria and effects of cueing might be present, but as for English speakers, intensive treatment (specifically LSVT LOUD) focusing on increasing vocal intensity shows promise for increasing intelligibility and quality of life in Mandarin speakers with hypokinetic dysarthria. Future studies should include a larger number of participants and probe the effects of behavioral speech modifications and intensive voice treatment on lexical tone, and consider which physiological mechanisms might be associated with production of lexical tone, given that lexical tone is often crucial to differentiating word meaning in Mandarin.

Parkinson’s disease remains a major neurodegenerative disease with prevalence that is second only to Alzheimer’s disease. Despite much advancement in the understanding of the pathogenesis of Parkinson’s disease, current therapeutic options are limited to those that are only symptomatic and are not disease-modifying. Furthermore, due to what seems to be increasingly complex underlying mechanisms of the disease, identifying a broadly applicable therapeutic strategy is difficult. There is much evidence surrounding the role of apoptosis and conversely, dysfunction of anti-apoptotic signaling in the progressive neurodegeneration that causes Parkinson’s disease. In particular, suppressed PI3K signaling has been implicated in the literature as a key event that occurs during neurodegeneration. Thus, regardless of the diverse upstream mechanisms that may lead to the disease, targeting a downstream effector of neuronal survival presents a therapeutic strategy that may be broadly effective against Parkinson’s disease. For this dissertation, we have developed a method to control the levels of active Akt, the main mediator of the PI3K signaling pathway, using an innovative protein destabilizing technique to create an inducible Akt, DD-Akt(E40K). This method permits the control of active Akt levels through a commonly used and blood-brain barrier permeable antibiotic, Trimethoprim. We have successfully established the inducibility of DD-Akt(E40K) across various cellular contexts, including neuronal cell types and conditions with suppressed PI3K signaling. This inducibility was found to be dose-responsive to Trimethoprim, reversible, and able to induce a known downstream substrate, FoxO4, that is an important regulator of cell survival. Importantly, DD-Akt(E40K) was found to inducibly protect neuronal PC12 cells against Parkinson’s disease mimetic toxins as well as growth-factor removal, indicating a proof of principle for the targeting of Akt activity as a protective strategy against Parkinson’s disease. The reported trophic effects of active Akt were also corroborated using our inducible DD-Akt(E40K) system in vivo, demonstrating significant increases in neuronal cell size within the substantia nigra of mice. Intriguingly, the inducibility of DD-Akt(E40K) was found to be dependent on the region of expression in the brain of mice such that the levels of this protective protein were not controllable by Trimethoprim in the substantia nigra but were controllable in the striatum. Taken together, the studies presented in this dissertation establish a new tool for the study of Akt signaling in various cellular and disease contexts and validate Akt as a promising therapeutic target in Parkinson’s disease. Our results also suggest an intriguing mechanism for the underlying pathology and selective degeneration observed in the disease.

Parkinson's disease is a progressive neurodegenerative disorder of the central nervous system, manifesting with both motor and non-motor symptoms. Autosomal recessive mutations in the FBXO7 gene have been identified to cause a rapidly progressing early-onset form of PD. Canonically, FBXO7 functions as a substrate-recruiting subunit of the SCF-type E3 ubiquitin ligase. However, it also has a variety of other atypical functions, such as cell cycle regulation, proteasome regulation, and mitophagy. The overall aim of this research was to characterise the functional role of FBXO7 in various in vitro and in vivo PD models. The models examined included FBXO7 shRNA knockdown SH-SY5Y cell lines, FBXO7 CRISPR knockout SH-SY5Y cell lines, primary patient fibroblasts with a FBXO7 mutation, and MEFs and tissues from a Fbxo7 KO mouse. My analysis of fibroblasts from a patient without FBXO7 expression revealed several interesting phenotypes. Briefly, the patient fibroblasts proliferated slower due to increased apoptosis and lower CDK6 and cyclin D1 expression, which led to fewer cells progressing through the G1 phase of the cell cycle. My experiments showed that these cells also had mitochondrial respiration defects, exhibiting lower basal respiration, ATP production, maximal respiration and spare capacity, in addition to complex I, III and IV deficiencies. Patient fibroblasts also had significantly lower levels of 12S and 16S ribosomal mRNA transcripts, which are necessary for the translation of mitochondrially encoded subunits of complexes I, III, and IV. Similar phenotypes were also observed in MEFs from a Fbxo7 KO mouse model, indicating conservation between human and mouse FBXO7 in regulating mitochondria, cell death and proliferation. In a tissue-specific KO mouse model of PD, where FBXO7 expression was ablated in the dopaminergic neurons, I analysed proteins regulated by FBXO7 which might be responsible for cell loss in the substantia nigra. I discovered that RPL23, a regulator of MDM2, was ubiquitinated by SCFFbxo7 using K48 chain linkages, promoting its degradation by the proteasome. This suggests that misregulation of the MDM2:p53 axis may underlie the cell loss observed in this conditional Fbxo7 KO mouse model. In conclusion, these results elaborate on the role of FBXO7 in mitochondrial biology, and identify a new ubiquitination substrate of FBXO7 in a mouse model of PD. It is hoped that by elucidating the potential pathogenic mechanisms of FBXO7 in rare familial forms of the disease, it will be possible to translate findings to the more prevalent sporadic forms of Parkinson's disease as well.

Objectifs: D’une part étudier les effets de la SCP à moyen et long terme chez les patients de notre centre ayant une forme génétique de MP, d’autre part effectuer une étude clinique, génétique et transcriptomique d’un groupe de patients parkinsoniens ayant une mutation du gène SCA2 (dits patients SCA2).Méthode: 1/ Effet de la SCP chez des patients ayant une forme génétique de MP: cinq patients ayant une forme génétique de MP, appartenant à une cohorte de 52 patients parkinsoniens ayant bénéficié d’une stimulation à haute fréquence du noyau sous-thalamique entre 1998 et 2000, ont été examinés avant la chirurgie puis à 1 et 5 ans. Les patients ont été évalués avec et sans L-dopa par plusieurs échelles: UPDRS II et III,dyskinésies, Schwab et England, Mattis et MADRS. Les résultats ont été comparés aux patients de la même cohorte ayant une forme sporadique de MP.2/ Etude des patients parkinsoniens SCA2 : la description clinique est rapportée rétrospectivement. Les études génétique et transcriptomique ont été effectuées chez 7 patients parkinsoniens et 8 patients cérébelleux SCA2, sur des cellules mononuclées sanguines. Le séquençage de l’ADN a permis de déterminer la longueur de la répétition de triplets CAG et d’identifier les interruptions par des triplets CAA. Le transcriptome de ces patients ainsi que de 13 témoins (sujets sains appariés sur le sexe et l’âge) a été réalisé sur deux plateformes de puces à ADN (Agilent et Illumina). L’analyse de l’expression des gènes chez les patients parkinsoniens et cérébelleux comparés à leurs contrôles respectifs a été réalisée avec le logiciel Genespring GX. Les gènes ayant une expression significativement différente (variation d’expression >1,3 et Welch t-test p< 0,05) ont été analysés à l’aide du logiciel Ingenuity Pathways Analysis qui identifie les voies canoniques significativement dérégulées.Résultats: 1/ Effet de la SCP chez des patients ayant une forme génétique de MP: les résultats de l’ensemble des parkinsoniens étaient comparables à la littérature. Les mouvements involontaires compliquant la dopathérapie s’amélioraient au cours du temps. Les patients ayant une forme génétique bénéficiaient d’un meilleur résultat que les autres parkinsoniens sur les signes dopasensibles et sur les complications dopa-induites.2/ Etude des patients parkinsoniens SCA2 : cliniquement, la MP était tout à fait classique, l’âge moyen de début était de 55,2 ans, tous les patients étaient dopasensibles et les complications typiques de la MP étaient constatées. Le séquençage de l’ADN a montré des expansions légèrement plus longues chez les patients cérébelleux (37-41 triplets) que chez les patients parkinsoniens (35-39). Les patients cérébelleux n’avaient pas d’interruptions CAA sur leur allèle muté. Tous les patients parkinsoniens avaient en revanche une séquence d’interruptions CAA inhabituelle. Pour ce qui concerne l’étude transcriptomique, nous avons constaté chez les patients cérébelleux et chez les parkinsoniens la dérégulation de l’expression de gènes connus pour interagir avec l’ataxine 2 (DDX6, PABP, gènes de la voie du métabolisme des inositol phosphates), ainsi que de gènes impliqués dans le métabolisme du cancer et dans l’immunité. Les patients parkinsoniens avaient un dérèglement des voies de signalisation de la sclérose latérale amyotrophique, du VEGF et de HIF1. Chez ces patients, l’expression de SNCA était diminuée, y compris chez les patients les moinsVIIsymptomatiques, alors qu’elle ne l’était pas chez les cérébelleux. Chez les patients cérébelleux, plusieurs voies concernant le métabolisme des ARN étaient dérégulées, ainsi que le métabolisme du phosphate inositol. Plusieurs voies canoniques impliquant l’apoptose étaient dans les 2 groupes de patients, avec une expression de gènes pro- et antiapoptotiques en faveur de l’apoptose chez les cérébelleux et en sa défaveur chez les parkinsoniens. / Objectives: First, to study the mid- and long term effects of DBS in patients with a genetic form of PD from our clinic, and second, to achieve a clinical, genetic and transcriptomic study of a group of parkinsonian patients bearing a mutation in the SCA2 gene (so called SCA2 patients)Methods: 1/ Effects of DBS in patients with a genetic form of PD: five patients with a genetic form of PD, belonging to a cohort of 52 PD patients who underwent a subthalamic nucleus high frequency stimulation between 1998 and 2000, were evaluated before surgery and then after 1 and 5 years with and without L-dopa, using several scales: UPDRS II and III, dyskinesia, Schwab and England, Mattis and MADRS. The results were compared with the patients of the same cohort having a sporadic form of PD. 2/ Study of the parkinsonian SCA2 patients: the clinical picture is related retrospectively. Genetic and transcriptomic studies were performed on blood mononuclear cells from 7 parkinsonian and 8 cerebellar SCA2 patients. DNA sequencing allowed to determine the length of the CAG triplets repeat and to identify the interruptions by CAA triplets. Transcriptomes of these patients and of 13 matched controls (healthy subjects paired according to gender and age) were profiled using 2 platforms of whole human genome expression micro-arrays (Agilent and Illumina). Analyses of differential expression in cerebellar and parkinsonian patients vs their respective controls were performed with GeneSpring GX software. Genes with significant differences (fold change >1.3 and Welch t-test p< 0.05) were analyzed using Ingenuity Pathway Analysis software which identified significantly deregulated canonical pathways.Results: 1/ Effects of DBS in patients with a genetic form of PD: the results concerning the whole cohort of PD patients were similar to the literature. L-dopa-induced involuntary movements improved over time. Patients with a genetic form of PD had a best result than other patients on dopa-responsive signs and dopa-induced complications.2/ study of the parkinsonian SCA2 patients: clinical features were very typical of PD, with a mean age of onset of 55.2 years, a good L-dopa responsiveness, and classical complications of PD. DNA sequencing showed slightly longer expansions in cerebellar (37-41 triplets) than in parkinsonian patients (35-39). Cerebellar patients had no CAA interruption on their mutated allele. All parkinsonian patients had an unusual pattern of CAA interruptions. Concerning the transcriptomic study, cerebellar and parkinsonian patients had a deregulation in the expression of genes known to interact with ataxin-2 (DDX6, PABP, genes in the inositol phosphates metabolism pathway), as well as genes involved in the metabolism of cancer and in immunity. Parkinsonian patients had a deregulation of amyotrophic lateral sclerosis, VEGF and HIF1 signaling pathways. In these patients, including the least symptomatic ones, SNCA expression was down-regulated, whereas it was not in cerebellar patients. In cerebellar patients, several pathways concerning the metabolism or RNAs were deregulated, as well as p53 signaling. Several canonical pathways involving apoptosis were deregulated in both groups of patients, with an expression of pro- and antiapoptotic genes in favor of apoptosis in cerebellar patients and going against apoptosis in parkinsonian patients. .

Parkinson’s Disease (PD) is a progressively debilitating neurodegenerative disease that affects the central nervous system and leads to severe difficulties with body movements. PD occurs due to the selective degeneration of neurons in the region of the brain known as the substantia nigra pars compacta. To date PD remains an incurable disease. Currently prescribed drugs provide only symptomatic relief to patients. Furthermore, they have considerable side effects and are often ineffective in the later stages of the disease or need to be used in combination in order to be effective. The role of neuroprotectants as a preventative measure in PD therapy is consequently receiving a great deal of attention and is being subjected to extensive research. This study sought to develop a novel prolonged-release drug delivery device for providing site-specific administration of newly researched neuroprotective agents. Nicotine was employed as the model neuroprotectant to incorporate in a novel reinforced crosslinked multiple-unit multi-polymeric drug delivery device. The study was the first of its kind to develop and employ the alkaloid for this purpose in a formulated delivery system. The device was intended to be one that provided zero-order prolonged release of the drug over a period of 1-2 months. The device was formulated such that its design was in keeping with the potential for implantation into the substantia nigra pars compacta to provide site-specific drug delivery. In order to do so, polymers, with biocompatible and bioerodable characteristics were selected to incorporate the drug within a reinforced crosslinked matrix. The study elucidated the mechanism of crosslinking of ionotropically crosslinked alginate spheres (gelispheres) with a variety of crosslinking agents through an evaluation of physicomechanical properties of the crosslinked system. The presence of barium in the crosslinked matrices generated densely networked gelispheres which retained their robustness following exposure to hydrating media and displayed promising potential for 4 entrapping drug molecules and retarding their release. The system was reinforced employing hydroxyethylcellulose (HEC) and polyacrylic acid (PAA). A Design of Experiments approach employing a Plackett-Burman screening design enabled optimisation of the proposed device in terms of reinforcing polymers (HEC and PAA) and crosslinking agents (barium and calcium). In order to further attenuate drug release rate the optimised crosslinked gelispheres were exposed to dilute hydrochloric acid (HCl) which significantly decreased gelisphere matrix swelling and erosion following exposure to simulated cerebrospinal fluid (CSF). These gelispheres were thereafter incorporated into a compressed release-rate modulating polymeric discs. Zero-order drug release was observed for a period of 50 days in simulated CSF when the optimised gelispheres were incorporated into compressed poly(lactic-co-glycolic) acid (PLGA) discs. Alternative approaches to modify drug release kinetics were also evaluated including the use of PLGA coatings on compressed hydroxypropylmethylcellulose-polyethylene oxide (HPMC-PEO) discs incorporating gelispheres and the use of crosslinked alginate-pectinate gelispheres as carrier systems to deliver PLGA-PLA (polylactic acid) microparticles incorporating drug. A Box-Behnken statistical design was employed to formulate and optimise the drug carrying PLGA-PLA microparticles. In both of the abovementioned cases we obtained sustained zeroorder drug release.