Alzheimer’s disease (AD) is a widespread neurodegenerative disorder that affects tens of millions of patients worldwide. Throughout the last two decades an incredible amount of time and resources have been funneled into hopefully finding medications that would provide a cure. Unfortunately, no such compound has been identified and instead the only FDA approved medications for AD to date target symptomatic management and may not even be effective for longer than a couple of years. To this end, this paper sets out to identify modifiable risk factors for AD as well as provide recommendations for clinicians on how best to utilize the tools currently available to them to treat AD. Additionally this paper addresses common flaws in AD clinical trial study designs and provides future research directions to expand outside of the popular amyloid hypothesis and instead potentially focus on a multi-pathway mechanism of the disease. The following thesis will outline several potential mechanisms that can lead to the hallmark pathologies seen in AD, primarily amyloid deposition and neurofibrillary tangles as well as neuronal death. The majority of commercial and research interest into AD has been focused on the amyloid hypothesis and the notion that stopping the formation of amyloid plaques would stop the disease course. However, in recent years other mechanisms and neurotoxic pathways such as inhibition of tricarboxylic acid (TCA) cycle enzymes, neuroinflammation, and tauopathy have been shown to contribute both to the formation of amyloid plaques as well as contributing to AD pathology in their own right. The modifiable risk factors explored in this paper include the effects of triglycerides as well as intake of antioxidant vitamins and omega-3-fatty acids, both of which are beneficial for brain health. This paper will also highlight some of the extensive research on the Apolipoprotein E gene and the effects the various alleles have on AD risk. These being the putative protective effect of the APOE2 allele, “neutral” effect of the most commonly found APOE3 allele, and finally the deleterious effects of the APOE4 allele, believed to be the strongest genetic risk factor for late-onset AD.

Calcium ions have important roles in cellular processes including intracellular signaling, protein folding, enzyme activation and initiation of programmed cell death. Cells maintain low levels of calcium in their cytosol in order to regulate these processes. When activation of calcium-dependent processes is needed, cells can release calcium stored in the endoplasmic reticulum (ER) into the cytosol to initiate the processes. This can also initiate formation of plasma membrane channels that allow entry of additional calcium from the extracellular milieu. The change in calcium levels is referred to as calcium flux. A key protein involved in initiation of calcium flux is Stromal Interaction Molecule 1 (STIM1), which has recently been identified as a sensor of ER calcium levels. STIM1 is an ER transmembrane protein that is activated by a drop in ER calcium levels. Upon activation, STIM1 oligomerizes with a plasma membrane protein, ORA1, to form calcium-selective plasma membrane channels. Dysregulation of calcium flux has been reported in cancers, autoimmune diseases and other diseases. STIM1 is a promising target in drug discovery due to its key role early in calcium flux. Here we review the involvement and importance of STIM1 in diseases and we discuss STIM1 as a viable target for drug discovery using computational chemistry methods to rapidly identify new molecules to target STIM1. Herein, computational techniques were used to understand the mechanistic role of STIM1 and virtual screening is in process to discover potential inhibitors of STIM1 activity. Also mutational analysis on STIM1 was performed computationally to see the effect it had on the protein computationally. It has been found that tumor cells and tissues, compared to normal cells, have higher levels of copper and possibly other metal ions. This presents a potential vulnerability of tumor cells that can serve as a physiological difference between cancer cells and normal cells and allows design of compounds that selectively target tumor cells while sparing normal cells. Recently we have identified compounds that have potential to inhibit the proteasome in tumor cells and induce cell death by mobilizing endogenous tumor copper resulting in in cellulo activation of the compound. These compounds hence act as pro-drugs, becoming active drugs in tumor cells with high copper content but remaining essentially inactive in normal cells, thereby greatly reducing adverse effects in patients. Such use would be of significant benefit in early detection and treatment of cancers, in particular, aggressive cancers such as pancreatic cancer which is usually not detected until it has reached an advanced stage. Six compounds were identified following virtual screening of the NCI Diversity Set with our proteasome computer model followed by confirmation with a biochemical assay that showed significant inhibition of the proteasome by the compounds in the presence of copper ions. In a dose response assay, NSC 37408 (6, 7-dihydroxy-1-benzofuran-3-one), our best compound, exhibited an IC50 of 3µM in the presence of 100 nM copper. Chagas’ Disease, a parasitic disease caused by the parasite Trypanosma Cruzi, is endemic to Latin America. The disease manifests itself in a short acute phase and a long chronic phase. Current treatments are effective only in the acute phase and are not used in the chronic phase due to toxicity of the drugs. Hence a new drug discovery approach was chosen for this disease. Cruzain is the major etiologic enzyme involved in the disease and is only present in the parasite. It is also an enzyme expressed by the parasite in both phases. Herein, a novel peptoid library containing hydromethylketones was constructed and screened against a virtual structure of cruzain. The peptoids thus found through this drug discovery effort can be used as potential drug candidates against cruzain. Computational techniques will help achieve a high degree of specificity and aid in proposing assays for determining compounds with high activity Alzheimer disease is the most common form of dementia. Its pathogenesis incorporates many potential targets for treatment. Among the targets identified, Apolipoprotein E4 (apoE4) is especially interesting due to its catalytic role in the degradation and clearance of amyloid beta (Aβ), a risk factor for Alzheimer disease. ApoE exists in 3 isoforms which directly impact its functionality in the body. There are characteristic structural differences between them. In ApoE4 ionic interactions exist between Arg-61 and Glu-255 residues, unlike the other isoforms. Hence interruption of this interaction by inhibitors may change the structure of apoE4 to a more linear structure as observed in the other isoforms. Virtual screening of the NCI diversity set on an energy minimized protein virtual structure was performed to identify potential small molecule inhibitors and to gain further understanding of interactions that can be targeted to inhibit this protein. From the top ligands in the NCI diversity set, a peptide library was designed to target the protein. Previous research has indicated that liquid assisted grinding (LAG) is efficient and reliable for cocrystal formation when compared to solvent crystallization and dimethyl formamide is the best solvent for grinding. Herein, we report the comparison of four screening processes: Slurry, solvent crystallization, LAG and dry grinding. Thirty-eight crystal forms containing the Narom··· COOH, Narom···OH supramolecular heterosynthons were screened in the process, and it was observed that slurry methodology is as efficient and reliable in forming cocrystals as solution crystallization. Twenty-four new crystal forms were also isolated herein. LAG was found to be more efficient as compared to dry grinding and was successful in the formation of twenty-five crystal forms of the thirty-eight screened. Dimethyl formamide still remains the best solvent for LAG. All our slurry experiments were performed in water and it was found that water can be used reliably for this method for compounds within a wide range of solubility, thereby increasing the versatility and usability of this method for future screening procedures.

Introduction : L’apolipoprotéine E (ApoE) est une protéine membranaire impliquée dans le catabolisme des lipoprotéines riches en triglycérides (TG). Le polymorphisme du gène de l’apolipoprotéine E epsilon 4 (APOE4) est considéré comme le plus grand facteur de risque génétique de la maladie d’Alzheimer tardive. Il est connu que la consommation d’acide gras polyinsaturé oméga 3 (AGPI n-3) serait associée à une diminution du risque de déclin cognitif. L’acide docosahexaénoïque (DHA) est un AGPI n-3 contenu dans les poissons riches en gras. Des résultats publiés par la professeure Mélanie Plourde ont démontré que suite à une diète riche en DHA, la concentration plasmatique en DHA était 3 fois moins élevée chez les porteurs de l’APOE4. Cela laisse supposer que les porteurs d’APOE4 auraient possiblement une perturbation dans l’homéostasie des AGPI n-3 au niveau entérocytaire. Objectif : Déterminer le profil en acides gras (AG) dans le duodénum et le jéjunum selon la diète et le polymorphisme de l’APOE chez le modèle animal murin. Évaluer si la diète et/ou le polymorphisme de l’APOE affectent l’expression protéique des transporteurs d’AG dans le jéjunum chez le modèle animal murin. Matériel et méthodes : Des souris knock-in pour les différentes formes de l’APOE (APOE3 ou APOE4) ont été utilisées. À 4 mois, celles-ci ont reçu pendant 8 mois soit une diète contrôle ou une diète riche en DHA. Après sacrifice des animaux, le duodénum et le jéjunum ont été prélevés. Une extraction des lipides totaux par la méthode de Folch a été effectuée. Le profil en AG a ensuite été réalisé par chromatographie en phase gazeuse. L’expression protéique des transporteurs d’AG entérocytaire a été mesurée par immunobuvardage de type western. Résultats et discussion : Les souris nourries avec la diète DHA avaient une augmentation en DHA dans le duodénum et le jéjunum établissant ainsi que le DHA est bien absorbé par les entérocytes dans ce modèle animal. Le génotype de l’APOE ne semble pas affecter spécifiquement le métabolisme du DHA puisqu’aucune différence significative n’a été observée pour le génotype. Par ailleurs, les souris ayant consommé la diète DHA avaient une diminution en acide arachidonique. Cette diminution semble plus prononcée chez les souris porteuses de l’APOE4, ce qui pourrait suggérer une demande plus importante en DHA chez les souris porteuses de l’APOE4. D’autre part, les souris nourries avec la diète DHA avaient une augmentation significative de l’expression relative des transporteurs d’AG Cd36 et Fabp2. Finalement, le transporteur d’AG Fabp1 tend à être diminué chez les souris porteuses de l’APOE4 Conclusion : Ces résultats suggèrent une possible perturbation dans le transit et l’exportation des AG sous forme de chylomicron plutôt que dans l’absorption de ceux-ci.

Indiana University-Purdue University Indianapolis (IUPUI) / Alzheimer’s disease (AD) is a neurodegenerative disorder resulting in progressive memory loss, brain atrophy, and eventual death. AD pathology is characterized by the accumulation of neurotoxic amyloid-beta (Aβ) plaques, synapse loss, neurofibrillary tangles (NFTs), and neurodegeneration. The APOE4 allele is associated with a 3-fold increased risk for AD and results in increased Aβ plaque deposition, reduced Aβ clearance, and reduced synaptic plasticity. Although APOE expression is upregulated in microglia in AD, APOE is expressed primarily by astrocytes in the CNS. It is not well understood how astrocytic APOE drives the mechanisms that result in worsened AD outcomes. Here, digital spatial profiling and bioinformatics data suggest that APOE4 causes transcriptional dysregulation in early AD and may disrupt neuronal processes via astrocytes. Whole transcriptome data from plaque and non-plaque regions in the cortices and hippocampus of 4- and 8-month-old AD model mice expressing humanized APOE4/4 or APOE3/3 (control) were analyzed. Transcriptional dysregulation was increased in APOE4/4 AD mice compared to that in APOE3/3 at 4 but not 8 months of age, suggesting that early dysregulation of APOE4-driven disease mechanisms may shape degenerative outcomes in late-stage AD. Additionally, APOE4/4 potentially functions via plaque-independent mechanisms to influence neuronal function in early AD before the onset of pathology. Single-nuclei RNA sequencing data were obtained from human post-mortem astrocytes and the bioinformatic analyses revealed a novel astrocyte subtype that highly expresses several top genes involved in functional alterations associated with APOE4, including neuronal generation, development, and differentiation, and synaptic transmission and organization. Overall, our findings indicate that APOE4 may drive degenerative outcomes through the presented astrocyte candidate pathways. These pathways represent potential targets for investigations into early intervention strategies for APOE4/4 patients. / 2024-05-22

La maladie d’Alzheimer est souvent précédée de troubles cognitifs légers (MCI) associés à la lésion du cortex entorhinal, une région interconnecté avec l’hippocampe. Cependant, un tiers des patients MCI présentent une rémission cognitive suggérant l’action de mécanismes compensatoires. Ces mécanismes pourraient être déficitaires chez les patients porteurs de l’allèle APOE4 présentant un MCI plus agressif.Par des approches multidisciplinaires chez la Souris, ce travail a démontré que la lésion entorhinale induit des déficits comportementaux et une hyperactivité de l’hippocampe. Or, le bourgeonnement des fibres cholinergique dans l’hippocampe compense ces déficits. Comme le bourgeonnement cholinergique est inhibé en présence de l’APOE4, cela pourrait contribuer au déclin cognitif exacerbé de ces patients. Par conséquent, l’inhibition de l’hyperactivité hippocampique chez les 50% de patients APOE4 représente une alternative prometteuse pour le traitement symptomatique du MCI. / Mild Cognitive Impairments (MCI) often precedes Alzheimer’s disease (AD) and is characterized by the loss of entorhinal neurons leading to a hippocampal disconnection. However, MCI patients also revert to normal cognition, suggesting compensatory mechanisms that alter the disease progression. This compensation may be impaired in patients bearing the APOE4 allele that are more prone to MCI, present less cognitive reversion and faster transition to AD.This work in mice, demonstrated that the sprouting of cholinergic fibers compensates entorhinal lesions through the reduction of the related hippocampal hyperactivity. As in APOE4 mice the cholinergic sprouting was altered in association with cognitive impairments, such impaired synaptic compensation may contribute to the faster cognitive decline of these patients. Therefore, supporting or mimicking the cholinergic control on hippocampal hyperactivity may represent a promising alternative therapeutic strategy for APOE4-carriers.

The APOE gene is of profound importance regarding the onset of Alzheimer's disease (AD). From the small physical differences among the protein products of the isoforms of this gene arises a profound difference in their physiologies. For example, the APOE2 isoform confers resistance to AD, the APOE3 isoform confers neutral susceptibility to AD, and the APOE4 isoform confers proneness to AD. L-cysteine is an amino acid that has several anti-AD properties, among which are its ability to sequester iron and form glutathione – a powerful antioxidant – and therefore may be a promising potential dietary supplement for ameliorating AD pathology. In our experiment, we fed Mus musculus (mice) homozygous for APOE2, APOE3, and APOE4 either a control diet or a diet high in L-cysteine. Using Western blotting analysis, we quantified Amyloid β (Aβ), hyper-phosphorylated Tau (HP-Tau), and the three APOE proteins that we extracted from post-mortem brains of APOE2, APOE3, and APOE4 homozygous mice of 3-, 6-, 9-, and 12-month ages. We calculated a three-way ANOVA on a sample of 86 mice to examine the effect of age, genotype, and diet on protein quantities. We found that administration of L-cysteine trends towards lowering levels of Aβ in each cohort, but this effect is statistically insignificant. On the other hand, L-cysteine caused a significant decrease in APOE production with regard to diet [F(1,62) = 6.17, p=0.02], indicating that less APOE is produced due to the decrease in Aβ burden. Furthermore, administration of L-cysteine revealed no significant impact on or trends regarding HP-Tau deposition between diet types for each cohort. However, we observed that L-cysteine appeared to nullify the increasing trend in HP-Tau deposition between APOE2 and APOE4 cohorts. Thus, L-cysteine may be weakly affecting HP-Tau deposition via its ability to somewhat reduce Aβ burden and consequently prevent the shutdown of the proteosomes responsible for the degradation and clearance of HP-Tau. Taken together, these data suggest that L-cysteine should be considered as an intervention for AD pathology.

Introduction: La consommation de poissons gras semble diminuer le risque de déclin cognitif lors du vieillissement. Cet effet serait potentiellement attribuable à deux acides gras oméga-3 concentrés dans le poisson: l'acide docosahexaénoïque (DHA) et l'acide eicosapentaénoïque (EPA). Cependant, ce lien n'est pas valide chez les personnes porteuses du génotype de l'apolipoprotéine E epsilon 4 (ApoE4), le facteur de risque génétique le plus important pour la maladie d'Alzheimer. Ces données suggèrent un débalancement dans le métabolisme du DHA chez les porteurs de l'ApoE4. Objectif: Évaluer si le polymorphisme de l'ApoE4 débalance le métabolisme d'un traceur DHA marqué au carbone 13 ([indice supérieur 13] C-DHA). Méthodologie: Quarante participants de plus de 50 ans ont été recrutés. De ce nombre, 14 sont des hommes et 26 sont des femmes. Ils ont consommé une dose unique de 50 mg de [indice supérieur 13] C-DHA afin de suivre son métabolisme sur une période de 28 j. L'incorporation plasmatique ainsi que la p-oxydation du [indice supérieur 13] C-DHA ont été suivis à l'aide d'échantillons de plasma et d'haleine prélevés avant la prise du [indice supérieur 13] C-DHA et 1 h, 2 h, 4 h, 6 h, 8 h, 24 h, 7 j, 14 j, 21 j et 28 j post-consommation. Résultats: 6 participants étaient porteurs de l'ApoE4 et 34 étaient non-porteurs. L'incorporation plasmatique du [indice supérieur 13] C-DHA était 3,7 fois moins grande chez les porteurs de l'ApoE4 2 h post-consommation (p = 0,04) et 1,9 fois moins grande 4 h post-consommation (p = 0,04) comparativement aux non-porteurs de l'ApoE4. La beta-oxydation du [indice supérieur 13] C-DHA était 1,8 fois plus grande chez les porteurs de l'ApoE4 7 j post-consommation (p = 0,05), 2,4 fois plus grande 21 j post-consommation (p = 0,02) et 2,3 fois plus grande 28 j post-consommation comparativement aux non- porteurs. Discussion/conclusion: Ces résultats suggèrent que les porteurs de l'ApoE4 montrent un débalancement dans leur métabolisme du [indice supérieur 13] C-DHA. Ceci pourrait modifier l'apport recommandé en DHA chez les porteurs de l'ApoE4 afin que ceux-ci soient protégés contre le déclin cognitif par la consommation d'acides gras oméga-3.

Linear mixed model (LMM) has the advantage of modeling the corelated data. Alzheimer’s disease (AD) is a chronic neurogenerative disease that affects the brain of the subject. No study was found to study the longitudinal effect of apolipoprotein E epsilon 4 (APOE4) genotype on the logical memory test total score in AD. A longitudinal data of 844 with AD, 2167 with cognitive normal (CN), and 4472 with mild cognitive impairment (MCI) participants who underwent logical memory examination test in the Alzheimer's Disease Neuroimaging Initiative (ADNI) were investigated. Episodic memory of the study participants was monitored based on a short story told to the participants and then participants asked to recall what was told. The multivariate LMM was used to determine the longitudinal changes in the logical memory test total score adjusting for age and sex. The Akaike information criterion (AIC) statistic and the Bayesian information criterion (BIC) statistic were used to select the best covariance structure. The repeated measures longitudinal analysis was performed using PROC MIXED in SAS 9.4. Both AIC and BIC statistics favor the unstructured correlated structure (UN). Using a UN model in the LMM, the APOE gene was is significantly associated with logical memory test total score (pUN covariance structure is the best. This study provided the first evidence of the effect of APOE4 genotype on the logical memory related to AD.

The purpose of this study is to explore the relationship between physical activity and working memory decline among older adults with APOE4 status. The APOE4 allele is currently the strongest predictor of risk for Alzheimer's disease and other related dementias. The publicly available data from the Health and Retirement Study was used to complete this Retrospective Longitudinal study. Three hypotheses were explored. H₁: It is expected that the presence of the APOE4 allele will be associated with worse overall working memory performance and a steeper rate of decline in working memory over time. H₂: Meanwhile, it is expected that participants that partake in a higher physical activity level will have better overall working memory performance and less decline in working memory than participants that only perform low or no activity. H₃: A moderation effect of physical activity on the relationship between working memory and APOE4 status is expected. A two-way repeated measure ANOVA was performed. Results indicted main effects for physical activity and years of education on the digit span task. Additionally, it was found that vigorous activity mitigates ill-effects of APOE4 on working memory. A statistical significance was found for the interaction between APOE4 status and physical activity. Findings suggest that physical activity may be prioritized as a primary intervention method for older and middle-aged APOE4 carriers.

No description available.