Molecular Biology Commons^™

The Regulation Of Extracellular Amyloid-Β Levels By Ionotropic Glutamatergic Transmission In An Alzheimer’S Disease Mouse Model, Jane Cecelia Hettinger

Arts & Sciences Electronic Theses and Dissertations

Brain extracellular concentration of the peptide amyloid-β (Aβ) is a major contributor to Alzheimer’s disease (AD) pathogenesis. High Aβ levels in the extracellular space precipitate aggregation of the peptide into soluble and insoluble toxic species. This process begins decades before cognitive impairment and triggers the cascade of pathology that eventually leads to AD. Synaptic activity is key to the regulation of extracellular Aβ levels. Presynaptic activity drives the production of Aβ, while postsynaptic receptor activation exhibits more nuanced regulation. For example, high levels of NMDA receptor (NMDA-R) activation have been shown to decrease Aβ production through the extracellular signal-regulated kinase …

Endocytic Trafficking Of The Amyloid Precursor Protein In Rat Cortical Neurons, Sahily Reyes

Dissertations & Theses (Open Access)

Amyloid-beta (Aβ) aggregation and deposition into extracellular plaques is a hallmark of the most common forms of dementia, including Alzheimer’s disease. The Aβ-containing plaques result from pathogenic cleavage of amyloid precursor protein (APP) by secretases resulting in intracellular production of Aβ peptides that are secreted and accumulate extracellularly. Despite considerable progress towards understanding APP processing and Aβ aggregation, the mechanisms underlying endosomal production of Aβ peptides and their secretion remain unclear. Using endosomes isolated from cultured primary neurons, we determined that the trafficking of APP from the endosomal membrane into internal vesicles of late endosome/multivesicular bodies (MVB) is dependent on …

Brain Energy Homeostasis And The Regulation Of N-Acetyl-Aspartate Metabolism In Development And Disease, Samantha Zaroff

Graduate School of Biomedical Sciences Theses and Dissertations

N-acetylaspartate (NAA) is a non-invasive clinical marker of neuronal metabolic integrity because of its strong proton magnetic resonance spectroscopy (H-MRS) peak and direct correlation with energetic integrity. Specifically, NAA is used to track the progression of neurodegenerative diseases due to the characteristic reduction of whole brain levels of NAA which occur simultaneously with reduced glucose utilization and mitochondrial dysfunction, but prior to the onset of disease specific pathology. However, NAA will also significantly increase simultaneously with energetic integrity during periods of recovery or remission in applicable disorders, such as traumatic brain injuries. Unfortunately, it remains enigmatic exactly why NAA is …

Pharmacological Antagonism And The Olfactory Code, Mihwa Na

Dissertations, Theses, and Capstone Projects

Mammals can detect and discriminate uncountable odors through their odorant receptors. To accommodate the countless and diverse odors, exceptionally large numbers of odorant receptor (OR) genes are expressed in mammals. In addition, the mammals utilize a combinatorial code, where an odorant molecule can activate multiple ORs; an OR also responds to a set of multiple odorants. In nature, an odor is often a complex mixture of multiple odorant molecules. The combination of the ORs activated by each constituent generates the unique olfactory code for the particular odor.

Some odorants can antagonize select ORs, as discussed in Chapter 1. An antagonist …

Amelioration Of Prenatal Alcohol Effects By Environmental Enrichment In A Mouse Model Of Fasd, Aniruddho Chokroborty-Hoque

Electronic Thesis and Dissertation Repository

Maternal alcohol consumption during pregnancy results in a spectrum of behavioural and cognitive deficits collectively known as Fetal Alcohol Spectrum Disorders (FASD). Currently, little is know about if and how the external environment may modulate these deficits. I have used C57BL/6 mice to study this interaction between prenatal alcohol exposure and the postnatal environment. Alcohol exposure during synaptogenesis produces high levels of anxiety-like traits and decreased memory performance. Alcohol-exposed mice (and matched unexposed controls) were put in 'environmentally-enriched' conditions of voluntary exercise, physical activities and cognitive stimulation to ascertain the effects of a positive postnatal environment. The results show that …

Sex Differences In Differential Fear Conditioning During The Acquisition And Consolidation Of Learned Safety, David Sylvan Reis

Theses and Dissertations

The ability to distinguish between threatening and non-threatening situations requires careful regulation of behavioral and physiological responses to stress and fear. Deficits in fear regulation are maladaptive and can lead to the development of anxiety disorders such as PTSD. Women are nearly twice as likely to develop PTSD as are men and laboratory animal studies have shown facilitated fear acquisition, resistance to fear extinction, deficits in extinction retention and impaired discrimination between danger and safety cues in females. Taken together this suggests a propensity for reduced inhibitory control over fear responding in females. Here we investigate the mechanisms underlying fear …

Chaperoning Ef Hands That Shape Calcium Response: Ncald, Hpca And S100b, Jingyi Zhang

Graduate School of Biomedical Sciences Theses and Dissertations

All organisms have an internal clock with a defined period between repetitions of activities. The period for circadian clock in human is 24.5 hours, while in mouse and rat, it is 23.5 hours. However, all organisms are forced to be in synchronization with their environment. A major environmental force that resets the internal clock to 24 hours is light. This phenomenon is defined as “light entrainment” or “phase-setting”. It is unclear how this entrainment process occurs. Studies from this laboratory indicate a role for two neuronal calcium sensor proteins: Neurocalcin  (NCALD) and S100B. For these two genes, mRNA as …

Pore-Lining Residues And Intracellular Magnesium Concentration Influence Connexin50 Gap Junction Unitary Channel Conductance, Mary Grace M. Tejada

Electronic Thesis and Dissertation Repository

Gap junction (GJ) channels mediate direct intercellular communication. Each GJ channel consists of two hemichannels and each hemichannel is a hexamer of connexins. GJs formed by different connexins display different unitary channel conductance (γ_j) and intracellular magnesium modulation. The underlying mechanisms are not fully clear. The present study investigates the effect of mutating putative pore-lining residues (G8, G46, and V53 individually or together) into glutamate in Cx50 on homotypic GJ channel properties. Expression of the triple and individual mutants in GJ-deficient N2A cells resulted in the formation of functional GJ channels similar to that of Cx50 GJs. However, …

Alpha-Synuclein: Insight Into The Hallmark Of Parkinson's Disease As A Target For Quantitative Molecular Diagnostics And Therapeutics, Baggio A. Evangelista

Honors Undergraduate Theses

Parkinson’s disease (PD) is the second-most common neurodegenerative disease after Alzheimer’s disease. With 500,000 individuals currently living with Parkinson’s and nearly 60,000 new cases diagnosed each year, this disease causes significant financial burden on the healthcare system - amassing to annual expenditures totaling 200 billion dollars; predicted to increase through 2050. The disease phenotype is characterized by a combination of a resting tremor, bradykinesia, muscular rigidity, and depression due to dopaminergic neuronal death in the midbrain. The cause of the neurotoxicity has been largely discussed, with strong evidence suggesting that the protein, alpha-Synuclein, is a key factor. Under native conditions, …

Retinal Disease Modeling And Drug Screening Using Stem Cell Derived Retinal Pigment Epithelium, Janmeet Singh Saini

Legacy Theses & Dissertations (2009 - 2024)

The eye is an intricate organ, possessing sensory receptors in the retina that are involved in visual perception. The retina consists primarily of the neural layer, referred to as the neural retina, and the pigmented layer, referred to as the retinal pigment epithelium (RPE). The neural retina and RPE develop and mature in a coordinated manner, and depend on each other for survival. In a mature healthy retina, the retinal photoreceptor outer segments interdigitate with the RPE monolayer, and they co-exchange key supportive factors. RPE cells are indispensable for the health of the retina as they are involved in a …

Epigenetic Editing To Validate Findings From Methylome-Wide Association Studies Of Neuropsychiatric Disorders, Robin F. Chan

Theses and Dissertations

DNA methylation is necessary for learning, memory consolidation and has been implicated in a number of neuropsychiatric disorders. Obtaining high quality and comprehensive data for the three common forms of methylation in brain is challenging for methylome-wide association studies (MWAS). To address this we optimized a panel of enrichment methods for screening the brain methylome. Results show that these enrichment techniques approach the coverage and fidelity of the current gold standard bisulfite based techniques. Our MBD-based method can also be used with low amounts of genomic material from limited human biomaterials. Psychiatric disorders have high prevalence and are often chronic …