The disturbances and abnormalities occurring in the components of the Acetylcholine (ACh) neurocycle are considered one of the main features of cholinergic sicknesses like Parkinson’s and Alzheimer’s diseases. A fundamental understanding of the ACh neurocycle is therefore very critical in order to design drugs that keep the ACh concentrations in the normal physiological range. In this dissertation, a novel two-enzyme-two-compartment model is proposed in order to explore the bifurcation, dynamics, and chaotic characteristics of the ACh neurocycle. The model takes into consideration the physiological events of the choline uptake into the presynaptic neuron and the ACh release in the postsynaptic neuron. In order to approach more realistic behavior, two complete kinetic mechanisms for enzymatic processes pH-dependent are built: the first mechanism is for the hydrolysis reaction catalyzed by the acetylcholinesterase (AChE) and the other is for the synthesis reaction catalyzed by the cholineacetyltransferase (ChAT). The effects of hydrogen ion feed concentrations, AChE activity, ChAT activity, feed ACh concentrations, feed choline concentrations, and feed acetate concentrations as bifurcation parameters, on the system performance are studied. It was found that hydrogen ions play an important role, where they create potential differences through the plasma membranes. The concentrations of ACh, choline and acetate in compartments 1 and 2 are affected by the activity of AChE through a certain range of their concentrations, where the activity of AChE is inhibited completely after reaching certain values. A detailed bifurcation analysis over a wide range of parameters is carried out in order to uncover some important features of the system, such as hysteresis, multiplicity, Hopf bifurcation, period doubling, chaotic characteristics, and other complex dynamics. The effects of the feed choline concentrations and the feed acetate concentrations as bifurcation parameters are studied in this dissertation. It is found that the feed choline concentrations play an important role and have a direct effect on the ACh neurocycle through a certain important range of the parameters. However, the feed acetate concentrations have less effect. It is concluded from the results that the feed choline is a more important factor than the feed acetate in ACh processes. The effects of ChAT activity and the choline recycle ratio as bifurcation parameters, on the system performance are investigated. It was found that as the ChAT activity increases, ACh concentrations in compartments 1 and 2 increase continuously. The effect of the choline recycle ratio shows that choline reuptake plays a very critical role in the synthesis of ACh in compartment 1, where it supplies the choline as a substrate for the synthesis reaction by ChAT. The concentrations of ACh, choline and acetate in compartments 1 and 2 are affected by the choline recycle ratio through a certain range of the choline recycle ratio; then, they become constant as the choline recycle ratio increases further. It is concluded from our results that choline uptake is the rate limiting step in the ACh processes in both compartments in comparison to ChAT activity. Based on partial dissociation of the acetic acid in compartments 1, and 2 of the ACh cholinergic system, the two-parameter continuation technique has been applied to investigate the pH range to be closer to physiological ranges of pH values. In addition, static/dynamic solutions of the ACh cholinergic neurocycle system based on feed choline concentration as the main bifurcation parameter in both compartments have been investigated. The findings of the above studies are related to the real phenomena occurring in the neurons, like periodic stimulation of neural cells and non-regular functioning of ACh receptors. It was found that ACh, choline, acetate, and pH exist inside the physiological range associated with taking into consideration the partial dissociation of the acetic acid. The disturbances and irregularities (chaotic attractors) occurring in the ACh cholinergic system may be good indications of cholinergic diseases such as Alzheimer’s and Parkinson’s diseases. The results have been compared to the results of physiological experiments and other published models. As there is strong evidence that cholinergic brain diseases like Alzheimer’s disease and Parkinson’s disease are related to the concentration of ACh, the present findings are useful for uncovering some of the characteristics of these diseases and encouraging more physiological research.

Bakgrund: svårigheter uppstår med kommunikationen mellan patient och sjuksköterskan vid insjuknande i Alzheimers sjukdom vilket leder till hinder i smärtbedömning av personer med Alzheimers sjukdom jämfört med bedömningen avpersoner utan kognitiv nedsättning. Syfte: syftet med litteraturstudien var att belysa vikten av korrekt smärtbedömning hos patienter med Alzheimers sjukdom. Metod: studien var en litteraturstudie, 12 artiklar samtliga kvantitativa som svarade mot studiens syfte har granskats och analyserats. Resultat och konklusion: bedömning av smärta hos patienter med Alzheimers sjukdom är komplex, slutsatsen är tvetydig då resultatet visar dels att personer med Alzheimers sjukdom har mer smärta respektive mindre smärta än personer utan kognitiv nedsättning. Bedömningsinstrumenten som undersöktes i studien visade sig vara relevanta men ansvar och kunskap från sjukvårdspersonalen som använder instrumentet var ett krav för att kunna utesluta felkällor av tecken på smärta så som onormala rörelser, beteende och ljud. Implikation: vidare forskning bör göras där fokus ligger på de enskilda diagnoserna istället för gruppen demenssjukdomar samt ökad kunskap hos sjukvårdspersonal på smärta i relation till Alzheimers sjukdom. / Background: difficulties with communication is shown in the progress of Alzheimer’s disease which leads to a difference in assessment of pain in persons with Alzheimer’s disease compared to persons without a cognitive impairment. Aim of the study: the aim of the study was to illuminate the importance of correct pain assessment in patients with Alzheimer’s disease. Method: the study was a literature review, 12 quantitative articles which met the study’s purpose was reviewed and analyzed. Results and conclusions: pain assessment in patients with Alzheimer’s disease is complex, the conclusion is ambiguous since the results show that people with Alzheimer’s disease has more in some studies and less pain in others in comparison with people without a cognitive impairment. The pain assessment tools that were examined in this study were shown to be relevant, but it was important that the staff using the instruments had to be able to rule out confounders of pain such as unusual movements, behaviour and sounds. Implication: further research should focus on the the separate diagnoses that are included in the dementia genre. Also an increased knowledge and awareness in the staff about pain in correlation with Alzheimer’s disease.

Alzheimer Disease (AD) is the most common neurodegenerative disorder in the world. One of the neuropathological hallmarks of AD is the senile plaques in the brain. The plaques are mainly composed of the amyloid β (Aβ) peptide. Aβ is generated from the amyloid precursor protein, APP, when it is first cleaved by the β-secretase and subsequently the γ-secretase complex. The γ-secretase complex cleaves at different sites, called γ and ε, where the γ-cleavage site generates Aβ peptides of different lengths and ε-cleavage generates the APP intracellular domain (AICD). The two major forms of Aβ is 40 and 42 amino acids long peptides, where the latter is more prone to aggregate and is the main component in senile plaques. The γ-secretase complex is composed of four proteins; Pen-2, Aph-1, nicastrin and presenilin (PS). The PS protein harbours the catalytic site of the complex, where two aspartate residues in position 257 and 385 (Presenilin 1 numbering) are situated. Most Familial AD (FAD) mutations in the PS gene cause a change in the γ-cleavage site, leading to a shift from producing Aβ40 to the longer more toxic variant Aβ42. Frequently, this often leads to impairments of the AICD production. Another substrate for the γ-secretase complex is Notch. It is important to maintain the Notch signaling since an intracellular domain (NICD) is formed after cleavage by the γ-secretase complex in the membrane (S3-site) and this domain is involved in transcription of genes important for cell fate decisions. It has been reported that certain APP luminal juxtamembrane mutations could drastically alter Aβ secretion, however their effect on AICD production remains unknown. In this study we want to analyse wether the juxtamembrane region is important for the AICD production. To gain more insight into the luminal juxtamembrane function for γ-secretase-dependent proteolysis, we have made a juxtamembrane chimeric construct. A four-residue sequence preceding the transmembrane domain (TMD) of APP (GSNK), was replaced by its topological counterpart from the human Notch1 receptor (PPAQ). The resulting chimeric vector C99GVP-PPAQ and the wildtype counterpart were expressed in cells lacking PS1 and PS2 (BD8) together with PS1wt. We observed that the chimeric construct did not alter production of AICD when using a cell based luciferase reporter gene assay monitoring AICD production. We also introduced a PS1 variant lacking a big portion of the large hydrophilic loop, PS1∆exon10, since our group has previously observed that this region affect Aβ production143. We found that the absence of the large hydrophilic loop in PS1 gave a 2-fold decrease in AICD-GVP formation from C99GVPwt compared to PS1wt.  The activity of PS1wt and PS1Δexon10 using C99GVP-PPAQ as a substrate gave similar result as the C99GVPwt substrate, i.e. a 2-fold decrease in AICD-GVP formation when comparing PS1Δexon10 with PS1wt. From this data we therefore suggest that the four residues in the juxtramembrane domain (JMD) (GSNK) is not altering ε-cleavage of APP when changed to Notch1 counterpart, PPAQ. Furthermore, we also show that the 2-fold decrease in AICD-production by the PS1Δexon10 molecule is not changed between the two substrates C99GVPwt and C99GVP-PPAQ. This indicates that the luminal region of APP is not directly involved in the ε-site processing. If the luminal region is affecting processing in the γ-cleavage sites, remains however to be investigated.

Recent Genome Wide Association Studies (GWAS) have identified a series of single nucleotide polymorphism (SNP)s that are associated with Alzheimer’s disease (AD). One of the SNPs, rs3851179 (G/A), is near the gene phosphatidylinositol-binding clathrin assembly protein (PICALM). To evaluate whether this SNP is associated with PICALM expression, we quantified PICALM mRNA in 56 brain cDNA samples. Using linear regression analysis, we analyzed PICALM expression relative to rs3851179, AD status, and cell type specific markers. An association was detected between rs3851179 and PICALM, microvessel mRNA, glial fibrillary acidic protein (GFAP) mRNA, and synaptophysin (SYN) mRNA. To gain clarity into other possible SNP mechanisms, we searched brain cDNA for PICALM splice variants. We identified several PICALM splice variants involving exons 13-19. To identify and gain an estimation of relative abundance of splice variants, we PCR-amplified across exons 13-20 in cDNA from six individuals, three rs3851179 GG individuals and three rs3851179 AA individuals. Sequencing the cloned isoforms we found that PICALM lacking exon 13 (delta 13) is the most abundant isoform. Other isoforms detected included deletion of exon 18-19. We targeted the latter part of the gene, exon 17-20, to investigate unequal allelic expression using next generation sequencing. Individuals heterozygous for rs76719109 (n= 35), located in exon 17, were used to study the abundance of G/T allele in cDNA and genomic DNA. When we analyzed the T:G allelic ratio, the variant lacking exons 18 and 19 showed unequal allelic expression (p-value < 0.001) in a subset of individuals. One individual was an outlier, showing overall unequal allelic expression, which maybe be harboring a rare mutation capable of modifying PICALM expression. The PICALM intronic SNP rs588076 was associated with delta 18-19 isoform splicing (p-value < 0.001). In conclusion, this study gained a greater insight into the role of AD genetics in PICALM expression and splicing.

The diffusible soluble oligomeric amyloid β-peptide (Aβ) has been identified as a toxic agent in Alzheimer’s disease that can cause synaptic dysfunction and memory loss, indicating its role as potential therapeutic targets for AD treatment. Recently an oligomer-specific sandwich biotin-avidin interaction based assay identified the Aβ oligomer dissociation potency of a series of dihydroxybenzoic acid (DHBA) isomers. Because the sandwich assay is an ensemble method providing limited size information, fluorescence correlation spectroscopy (FCS) was employed to provide single molecule resolution of the disassembly mechanism. Using FCS coupled with atomic force microscopy, we investigated the size distribution of fluorescein labeled synthetic Aβ oligomers at physiological concentrations, and monitored in real time the change of size and mole fraction of oligomers in the presence of dissociating agents or conditions. The higher-order dissociation process caused by DHBA isomers produced no transient oligomeric intermediates, a desirable feature for an anti-oligomer therapeutic. Urea and guanidine hydrochloride, in contrast, produced a linear dissociation with a progressive decrease of size and mole fraction of oligomers. FCS allows the facile distinction of small molecule Aβ oligomer dissociators that do not produce stable potentially toxic oligomeric Aβ intermediates.

Quantitative magnetic resonance imaging (MRI) was used to assess global and regional cerebral volumes in patients with a clinical diagnosis of subcortical vascular dementia (VD) and Alzheimer’s disease (AD). Whole brain volume, cerebrospinal fluid volume, volumes of the temporal, frontal and parietal lobes, the cerebellum and the amygdala-hippocampus complex were determined using a personal computer-based software. Seventeen patients with VD, 22 patients with AD and 13 healthy controls were included. Analysis of covariance using age as covariate demonstrated significant mean differences between controls and dementia groups with respect to all morphological parameters. However, apart from the volume of the cerebellum no significant volumetric differences were found between VD and AD. These results indicate that MRI-based volumetry allows differentiation between AD or VD from normal controls and that measurement of cerebellar volume may be of use to separate vascular and degenerative dementia. However, since the distribution of cerebral atrophy in both dementia groups is very similar, it is suggested that the atrophic changes are not specific to the underlying cause but rather reflect the selective vulnerability of neuronal structures. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Aujourd’hui, malgré la description des mécanismes à l’origine du développement de la dépression et de la MA, aucun traitement curatif n’existe pour ces pathologies suggérant l’implication d’un autre phénomène. L’un des processus retrouvé communément dans ces pathologies est la neuroinflammation. Or pour le moment, les essais cliniques entrepris dans la MA afin de réduire la neuroinflammation n’ont pas permis d’aboutir à une amélioration significative des symptômes. L’une des raisons de cet échec serait une mauvaise fenêtre thérapeutique qui aurait pour conséquence d’exacerber les effets délétères de la neuroinflammation. Ceci met en lumière la méconnaissance de la cinétique de la neuroinflammation dans la MA. Ainsi notre travail de thèse avait pour but, d’une part, d’étudier l’impact d’anti-inflammatoires comparativement à celui d’antidépresseur dans la dépression chez la souris, et d’autre part, d’étudier l’impact de l’utilisation d’antidépresseur et d’anti-inflammatoires dans un modèle murin de MA. / Today, despite the description of the mechanisms underlying the development of depression and AD (Alzheimer’s disease), no cure exists for these diseases suggesting the involvement of another phenomenon. One of the processes commonly found in these pathologies is neuroinflammation. However, clinical trials undertaken in the AD to reduce neuroinflammation have not led to a significant improvement of symptoms. One reason for this failure could be a bad therapeutic window which would result in the increase of deleterious effects of neuroinflammation. This highlights the lack of understanding of the kinetics of neuroinflammation in AD.

Infectious and neurodegenerative diseases continue to be a major concern worldwide. In spite of the great advances in drug therapy for treating various infectious and neurodegenerative diseases, there is still an urgent need for new and improved drugs due to increasing drug resistance among pathogens, emergence of new pathogens, ease of transmission of infections, ineffective available treatments, toxicity associated with current standard of care, aging populations and the lack of better alternative treatment options. The first part of this manuscript (chapters 1 - 5) describes the synthesis of novel agents active against Leishmania donovani. According to the World Health Organization (WHO), a significant number of deaths worldwide can be attributed to infectious diseases – particularly neglected tropical diseases (NTDs), one of which is leishmaniasis - a complex and clinically diverse disease transmitted through the bite of an infected female phlebotomine sand-fly. The pathogen that causes leishmaniasis develops through a complex life cycle via different morphological changes. Its clinical presentations range from the less severe (cutaneous) to lethal/fatal (visceral) forms depending upon the level of systemic involvement, infecting species and the endemic environment. Treatments (and vaccines) must be species-specific to be particularly effective since sensitivity to commonly used drugs is largely species-specific. Heat shock protein 90 (Hsp 90) has been shown to promote the differentiation of the protozoan parasite that causes leishmaniasis from the promastigote stage to the amastigote pathogenic stages. To this end a series of compounds were prepared based on known Hsp 90 inhibitors, SNX2112 and XL888. The synthetic approach allows the probing of a hydrophobic pocket and rapid access to a collection of anti-leishmanial compounds. The most active compound, was found to be more than twice as active as the climivally used drug, miltefosine, in an infected J774 macrophage at IC50 = 0.65 µM. The second part of this manuscript (chapters 6 - 9) describes the synthesis novel anti-Alzheimer’s agents. Alzheimer’s disease is a progressive neurodegenerative disease believed to be caused by tau hyperphosphorylation and plaque aggregation in the brain. It is known to affect about 44 million people worldwide and it is marked as the 6th leading cause of death in the United States. Slingshot homology-1 (SSH1) proteins, important protein phosphatases, are promising targets for the discovery of a new generation of small molecule inhibitors as treatment for Alzheimer’s disease, since SSH1 is known to contribute to both tau hyperphosphorylation and plaque aggregation in the brain. Through structure and activity relationships (SAR) studies, two (2) series of compounds were synthesized, thiazoles and pyridones, bearing a carboxylic acid or phosphonic acid functionality as inhibitors of SSH1 enzymes. In the preliminary screening efforts against SSH1 phosphatase activity, the thiazole series were found to be more potent at inhibiting the phosphatase activity than the pyridone series. Among the active thiazole series, eight (8) analogs exhibited significant inhibitory activity over the initial hit compound, observed via phosphatase inhibition curves (using a pNPP phosphatase assay). Further investigations into the molecular target (SSH1) are currently underway.

Introdução: A Doença de Alzheimer (DA) é uma desordem neurodegenerativa e a forma mais comum de demência. Processos inflamatórios parecem desempenhar importante papel na fisiopatologia da DA. A neuroinflamação é caracterizada pela ativação da microglia e a liberação de citocinas inflamatórias, tais como IL-1β, IL-6 e TNF-α. Porém, não se sabe qual é a real contribuição destes marcadores inflamatórios no desenvolvimento da DA. Objetivos: A proposta deste estudo é avaliar a possível relação entre marcadores inflamatórios no liquido cefalorraquidiano de indivíduos com comprometimento cognitivo leve amnéstico (CCL-a), com 60 anos ou mais, e comparar com controles saudáveis da mesma faixa etária. Métodos: Foram examinadas as concentrações de IL-1β, IL-6 e TNF-α no líquido cefalorraquidiano de sujeitos com CCL-a e em controles pelo método ELISA. Diagnósticos de CCL-a foram baseados na anamnese e nos critérios de Petersen, corroborados pela escala CDR. Para avaliar a função cognitiva o teste de memória e reconhecimento de palavras do CERAD e o Teste do Relógio foram aplicados aos participantes. Para a avaliação de sintomas depressivos usou-se o GDS. Resultados: Este estudo demonstrou diminuição significativa nos níveis de IL-1β (13.735 vs 22.932 pg/mL; p <0.001) e TNF-α (1.913 vs 2.627 pg/mL; p: 0.002), mas não nos níveis da IL-6 (4.178 vs 5.689 pg/mL; p: 0.106), entre casos e controles. Indivíduos com IL-1β < 17 pg/mL possuem 7.2 (CI: 1.5-36; p: 0.016) mais chances de evoluírem à CCL-a. Além disso, houve correlação positiva entre IL-1β e a pontuação da lista de palavras do CERAD (rs: 0.299; p: 0.046). A análise de regressão linear mostrou que os níveis de IL-1β podem explicar 13.7% (β: 24.545; p: 0.012) da variância da pontuação do CERAD, o que sugere uma dependência linear direta. Conclusões: A neuroinflamação, mediada pela IL-1β e pelo TNF-α, provavelmente possui importante papel na prevenção de CCL-a. / Introduction: Alzheimer Disease (AD) is a neurodegenerative disorder and the most common form of dementia. Inflammatory processes may play a significant role at the pathophysiology of AD. Neuroinflammation is characterized by activation of microglia and the release of inflammatory cytokines, such as IL-1β, IL-6 and TNF-α. Although, it is unknown what is the real contribution of these inflammatory markers in the development of AD. Aims: The purpose of this study is to assess the possibly relationship between inflammatory markers in CSF of amnestic MCI subjects, with sixty years or older, and compare to aged healthy controls. Methods: We examined concentrations of IL-1β, IL-6 and TNF-α at CSF of amnestic MCI subjects and controls by ELISA. MCI diagnoses were based on anamnesis and Petersen criteria, corroborated by CDR. To assess the cognitive function the word list memory test and word recognition of CERAD and Clock Drawing Test were applied to subjects, and to evaluated depression symptoms the GDS was used. Results: This study demonstrated significant diminish in the levels of IL-1β (13.735 vs 22.932 pg/mL; p <0.001) and TNF-α (1.913 vs 2.627 pg/mL; p: 0.002), but not IL-6 (1.913 vs 2.627 pg/mL; p: 0.002), between cases and controls. Individuals with IL-1β < 17 pg/mL were at a 7.2 (CI: 1.5-36; p: 0.016) increased odds of aMCI. Furthermore, there was a positive correlation between IL-1β and the CERAD word list score (rs: 0.299; p: 0.046). The linear regression analysis showed that IL-1β levels can explain 13.7% (β: 24.545; p: 0.012) of the variance on this CERAD subscore, suggesting a direct linear dependence. Conclusion: Neuroinflamation mediated by IL-1β and TNF-α may play an important role in preventing aMCI.

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