Pharmacology, Toxicology and Environmental Health Commons^™

Characterizing Hexavalent Chromium Neurotoxicity Across Laboratory Models., Samuel Thomas Vielee

Electronic Theses and Dissertations

Hexavalent chromium [Cr(VI)] is a ubiquitous environmental pollutant and potent toxicant. Exposure to Cr(VI) in drinking water is primarily associated with cancers, inflammation, and hepatotoxicity; however, recent studies have identified Cr(VI) as a neurotoxicant in rodent and cell culture models. The literature suggest chromium accumulates in the brain, induces widespread neurodegeneration, and alters rodent behaviors. Despite these data, we lack a detailed and consistent assessments of Cr(VI) neurotoxicity across models, and interactions between aging and Cr(VI) neurotoxicity are not reported in the literature. In this dissertation, we characterize Cr(VI) neurotoxicity across 3 laboratory models: Sprague-Dawley rats, Caenorhabditis elegans, and …

Exposure To Pm2.5 And Aging., Daniel Chris Gomes

Electronic Theses and Dissertations

Inhalation of fine airborne particulate matter (PM_2.5) is an environmental risk factor for numerous health disorders, including cardiovascular diseases (CVD). While several studies have shown that PM_2.5 exposure can induce oxidative stress, DNA damage, and inflammation, the underlying mechanisms that translate these effects into systemic pathology remain poorly understood. Some recent studies have shown that PM_2.5 exposure can lead to telomere shortening in leukocytes, but the generality of this outcome and contribution to endothelial dysfunction has not yet been fully explored. We hypothesized that PM_2.5inhalation accelerates cellular aging and senescence in both circulating peripheral …

A Ralgef Inhibitor Suppresses Lung Cancer Stem Cell Development And Tumorigenesis., Raphael Ngozichi Suarez Jigo

Electronic Theses and Dissertations

The RALGEF family of proteins are direct downstream effectors of the RAS oncoprotein. RALGEFs act as guanine nucleotide exchange factors (GEFs) for downstream RAL proteins, thus tying RAS to the regulation of RAL. Genetic studies have demonstrated RAL proteins to be key drivers of RAS-driven transformation and metastasis. Furthermore, this pathway has been implicated in chemoresistance, exocyst-mediated transport, and the modulation of cancer stem cells. Previous work in our lab reported the activity of a novel pan-RALGEF inhibitor (C4-180) against RAS-driven pancreatic cancer models. Here we show the agent to be active against in vitro and in vivo models of …

Effect Of Histidine Tag On The Enzymatic Activity Of Pseudolysin And Its Interaction With The Streptomyces Metalloprotease Inhibitor (Smpi) Protein, Adewale Adeboye Adewole

Electronic Theses and Dissertations

Pseudolysin (PLN) protein is a major virulent factor in Pseudomonas aeruginosa infection. PLN belongs to the family of zinc-dependent metalloproteases. It is naturally inhibited by a smaller protein called streptomyces metalloprotease inhibitor (SMPI), secreted by Streptomyces nigrescens. Previous and current studies demonstrate that the interaction between PLN and SMPI offers unique mechanistic insights for drug development against infections caused by P. aeruginosa. This study investigated the effect of N-terminal Histidine (His) tag on the enzymatic activity of PLN and its interaction with SMPI. His-tagged PLN and SMPI proteins were expressed in bacteria and purified by affinity chromatography …

Hierarchy In Sensation: Exploring The 40 Hz Auditory Steady State Synchrony In The Primary Auditory And Prefrontal Association Cortices, Deepshila Gautam

Electronic Theses and Dissertations

Auditory processing begins in the cochlea and ascends through brainstem relays to the cortex, where sound features with increasing complexity are encoded. The 40 Hz auditory steady-state response (ASSR) reflects induced gamma synchrony shaped by local cortical circuit dynamics. Disrupted 40 Hz ASSR is a consistent finding in schizophrenia, linked to N-methyl-D-aspartate receptor (NMDAR) hypofunction in inhibitory interneurons, making it a promising translational biomarker. While multiple ASSR generators have been identified, it is not known if these are redundant or represent unique activity. This dissertation investigates regional differences in 40 Hz ASSR across two principal generators: the primary auditory cortex …

Analysis Of An Ethanol Sensitive Bmp-Nkx2.3-Fgf Signaling Pathway In Pouch Morphogenesis., Hieu Dai Le Vo

Electronic Theses and Dissertations

Craniofacial malformations lie at the heart of Fetal Alcohol Spectrum Disorders (FASD). While there is growing evidence for a genetic component to FASD, little is known of the cellular mechanisms underlying these ethanol-sensitive loci in facial development. Bone Morphogenetic Protein (Bmp) signaling pathway dependent pouch formation is a key mechanism in facial development. We have previously shown that multiple Bmp mutants are sensitized to ethanol-induced facial defects. However, ethanol does not directly impact Bmp signaling. This suggests that downstream effectors, like nkx2.3 and Fibroblast Growth Factor (Fgf) signaling, may mediate the impact of ethanol on Bmp mutants. Here, I …

Mixture Effects On Metal Accumulation In The Asian Clam, Corbicula Fluminea, Mark A. Huff

Electronic Theses and Dissertations

Field collected Corbicula fluminea were exposed to trace level copper, lead, and zinc with the aim of examining the preferential accumulation between the soft tissue and shell. Metal levels were based on those in a permitted industrial effluent. At 1X effluent and 2X effluent exposure levels, copper was found to preferentially accumulate in the clam soft tissue, lead was found to preferentially accumulate in the clam shell, and zinc was found to excrete back into the diluent after preferentially accumulating in the clam soft tissue. When exposed as a mixture at 1X effluent levels, copper and lead were found to …

Impact Of Unconventional Gas Extraction On Tributaries Of Tenmile Creek, Greene County, Pennsylvania: A 12-Year Perspective, Christian L. Beall

Electronic Theses and Dissertations

Much of southwestern Pennsylvania has been central to a rapid increase in development for unconventional natural gas extraction in the past two decades. The continued monitoring of streams over their lifetime as extraction sites is pivotal to understanding the effects of fracking on local waterways and their ability to provide for wildlife and human use. Here, using multiple indices of biotic integrity (IBI), I perform analyses of fish and macroinvertebrate communities as well as water chemistry on two streams, Bates Fork (with shale wells) and Fonner Run (without), as part of a follow-up to work performed there from 2010-2012. Fish …

Mechanisms Of Particulate Hexavalent Chromium-Induced Inhibition Of Homologous Recombination Repair: Targeting The Bcdx2 Complex Considered Through A One Health Perspective., Aggie W. Brownell

Electronic Theses and Dissertations

Lung cancer remains the leading cause of cancer death, often linked to smoking. However, smoking alone does not account for all cases. Exposure to environmental metals like hexavalent chromium [Cr(VI)] also contributes to lung cancer. Cr(VI) causes lung cancer by inducing chromosome instability (CIN), an early hallmark of its carcinogenic mechanism. While it has been established that Cr(VI) induces chromosome instability, the precise mechanisms underlying the chromosome instability are poorly understood. This dissertation investigates the mechanisms of carcinogenesis associated with zinc chromate, a particularly potent particulate form of hexavalent chromium. Studies show Cr(VI) induces DNA double-strand breaks and impairs the …

Translation Of The Carcinogenic Dna Breakage-Repair Inhibition Mechanism For Hexavalent Chromium To Its Key Targets: Lung Epithelial Cells, Lung Tissue And Impacts On The Genome., Idoia Meaza Isusi

Electronic Theses and Dissertations

Lung cancer is the leading cause of cancer death worldwide. Hexavalent chromium [Cr(VI)] is a human lung carcinogen with widespread occupational and environmental exposure. Despite the known health risks, how Cr(VI) causes lung cancer remains unclear. This dissertation investigates the mechanisms of Cr(VI)-induced carcinogenesis. Cr(VI) causes DNA damage, specifically DNA double strand breaks, and inhibits homologous recombination repair, a high-fidelity repair pathway. Unrepaired DNA double strand breaks or those repaired through error-prone pathways, progress to chromosomal damage, and chromosome instability. The latter is a common characteristic of Cr(VI)-exposed cells, and a hallmark of lung cancer. Although the mechanism of Cr(VI)-induced …

Investigating The Role Of The Hypocretin/Orexin System In A Novel Model Of Polysubstance Dependence, Tyler Zarin

Electronic Theses and Dissertations

Substance use disorders (SUD) in the United States are steadily increasing. Potent and dangerous substances such as methamphetamine (MA) and fentanyl (FEN) are often co-used as a polysubstance (POLY), either intentionally or unknowingly as FEN is a common adulterant. SUD is characterized by physiological and psychological dependence involving the negative reinforcement of anhedonia and withdrawal which drive hypermotivated drug-taking behaviors. Current theory suggests that recruitment of hypocretin/orexin (HCRT) neuropeptide in reward and stress associated brain regions contributes to drug dependence. Despite strong evidence for HCRT’s role in mono-drug dependence, a relevant model for POLY dependence has yet to be developed, …

Advancing Continuous Manufacturing: The Role Of Process Analytical Technology In Process Development, Samuel R. Henson

Electronic Theses and Dissertations

The pharmaceutical industry is actively pursuing technologies which improve manufacturing processes with the goal of producing high-quality pharmaceutical products for patients, manifesting in an industry-wide investment in continuous manufacturing (CM). Process analytical technology (PAT) has been recognized for its successful monitoring of critical quality attributes during routine production and is often cited alongside CM due to its ability to make timely, in-line measurements of intermediate materials. Various PAT tools are valuable in process development, particularly as continuous wet granulation processes are developed for use within pharmaceutical manufacturing. This work applied PAT and chemometric modeling during CM process development to enhance …

The Multipurpose Dna Repair/Redox Protein Ape1 In Rodent And Human Lewy Body Disease, Kristin Marie Miner

Electronic Theses and Dissertations

Lewy body disorders are a family of neurodegenerative conditions characterized by proteostatic and redox disequilibrium, leading to deposition of the abundant protein α-synuclein in hallmark inclusions and oxidative damage to DNA. Sublethal oxidative DNA damage in neurons is repaired predominantly by the base excision repair pathway, which involves the coordinated activity of several enzymes, including apurinic/apyrimidinic endonuclease 1 (APE1). Despite emerging connections between α-synuclein, oxidative stress, and DNA damage/repair, along with evidence demonstrating the multifunctional nature of APE1, the link between APE1 and α-synuclein has not yet been explored.

Here, we conducted a broad investigation of APE1 in the context …

The Effect Of Novel Microtubule Modulators On Experimental Lewy Body Disease, Anuj S. Jamenis

Electronic Theses and Dissertations

In Lewy body disorders, α-synuclein aggregates are believed to destabilize the microtubular framework. However, microtubules are a challenging therapeutic target, as excessive rigidity or flexibility afforded by microtubule modulators may be neurotoxic. Thus, the objective of the present study was to evaluate dual-acting microtubule- stabilizing/destabilizing agents in cellular and animal models of early-stage Lewy body disease.

In Aim 1 we tested the dual-acting tricylic pyrimido[4,5-b]indole analogs AG161-47 and AG161-41 in an in vitro preformed fibril induced model of Lewy body disease. We found that both compounds reduced preformed fibril-seeded α-synucleinopathy without toxicity in primary hippocampal cultures. AG161-47 subtly impacted microtubule …

Surface Water Quality Assessment Of Mingo Creek County Park: The Impacts Of Extractive Industries, Mikayla J. Bayto

Electronic Theses and Dissertations

Historical and current extraction operations and infrastructure, including natural gas pipelines, conventional and unconventional oil and natural gas drilling, longwall coal mining, and strip coal mining, occur throughout the Mingo Creek watershed of Washington County, Pennsylvania, including Mingo Creek County Park. Mingo Creek and several associated tributaries flow through Mingo Creek County Park, eventually discharging into the Monongahela River. An independent water quality study was conducted from June 2020 through July 2023 in Mingo Creek County Park to determine if historical and current extraction activities impact Mingo Creek and its associated tributaries. Weekly sampling of Mingo Creek and associated tributaries …

Anthropogenic Litter In Urban Waterways: An Analysis Of Litter, Urbanization, And The Emerging Role Of Citizen Science In Beargrass Creek, Louisville, Ky., Ella Swigler

Electronic Theses and Dissertations

This thesis addressed the ever growing presence and persistence of anthropogenic litter (AL) in urban waterways. AL has been studied in marine environments, but research gaps exist in riverine ecosystems. Most of the AL that reaches the Earth’s oceans is carried by urban rivers, so understanding the relationship between these waterways and AL is critical in effectively fighting AL accumulation, especially for legacy plastic pollutants. The study explored fifteen sites throughout Beargrass Creek and recorded the quantity and type of AL present throughout the summer and fall of 2023. The National Geographic Marine Debris Tracker App was employed to successfully …

Study Of The Effects Of Chronic Cadmium Exposure On The Pathogenesis Of Pulmonary Arterial Hypertension., Dakotah Dominique Cathey

Electronic Theses and Dissertations

We reported pulmonary artery hypertension (PAH) patients had elevated levels of Cd in both blood and urine, therefore, this study tested whether Cd directly induces PAH or facilitates PAH pathogenesis in mouse models. C57/6J mice were initially exposed to drinking water with or without 5ppm Cd for 8 weeks. Then, half the mice in both control and Cd groups were given SU5416 and hypoxia (SuHx) for 4 weeks to induce PAH, resulting in 4 subgroups: Control, Cd, PAH, and Cd+PAH. Diastolic and systolic functions of the left and right ventricles (LV, RV) were examined with echocardiography before and after PAH. …

The Impact Of Environmental Pollutants On Alcohol-Associated Liver Disease Pathogenesis., Tyler Charles Gripshover

Electronic Theses and Dissertations

Steatotic liver disease is brought upon by differing etiologies and its global prevalence is expected to keep increasing over the next several decades. Particularly, alcohol-associated liver disease (ALD) manifests from excessive alcohol consumption where the liver retains lipids and progresses with metabolic dysfunction. Previous studies have demonstrated that environmental pollutants, polychlorinated biphenyls (PCBs) promote metabolic dysfunction associated steatotic liver disease (MASLD), in diet-induced obesity models. However, it is unknown if environmental pollutants may also promote ALD pathogenesis. Thus, this dissertation focuses on characterizing the effects of PCB126 in a rodent ALD model followed by multiple ‘Omics approaches to identify mechanisms …

Using A Toxic Aging Coin To Assess Hexavalent Chromium-Induced Neurotoxicity., Samuel Thomas Vielee

Electronic Theses and Dissertations

We are facing an aging crisis, with 20% of the U.S. population projected to be geriatric (65+) by 2030 and live another 40+ years. Age-related diseases accompany a growing geriatric population, emphasizing the need to understand their etiology. Environmental pollutants compound this crisis by: 1) geriatrics are more susceptible, exacerbating age-related diseases and comorbidities, and 2) they accelerate biological aging, inducing age-related diseases at younger ages. We address this crisis using a ‘toxic aging coin’ approach; heads examines how age impacts toxicity, tails examines how chemicals accelerate aging. This thesis applies the heads side for Cr(VI)-induced neurotoxicity across ages. We …

Effects Of Environmental Pollutants On Liver Disease: Role Of The Gut-Liver Axis., Ngozi Victoria Adiele

Electronic Theses and Dissertations

Polychlorinated biphenyls (PCBs) and polystyrene (PS) microplastics are environmental pollutants associated with various diseases including toxicant associated fatty liver disease (TAFLD). Previously, exposure to Aroclor 1260 (a PCB mixture) has been shown to exacerbate TAFLD, partly through Aroclor 1260 induced gut dysbiosis. Studies has also demonstrated that PS exposure alters gut microbiome composition and induced obesity. However, the effects of Aroclor 1260 on the gut and the effects of PS on the liver are still understudied. Therefore, we hypothesize that environmental pollutants will disrupt the gut-liver axis through changes in gut and its microbiome as well as changes in liver …

Epitranscriptomic Regulation In Breast Cancer And Pcb-Induced Liver Disease., Belinda Petri

Electronic Theses and Dissertations

Post-transcriptional RNA modifications including N6-methyladenosine (m6A) regulate mRNA stability, splicing, and translation. My research examined m6A in two disease models: breast cancer (BCa) and non-alcoholic fatty liver disease (NAFLD). Acquired resistance to endocrine therapies (ET) develops in approximately 20% of BCa patients with estrogen receptor α positive (ER+) tumors following treatment. The mechanisms by which tumor cells evade ET are not completely understood. Using a cell line model, we investigated the role of an m6A reader protein, HNRNPA2B1 (A2B1) that is upregulated in ET-resistant ER+ BCa cells. Stable overexpression of A2B1 in ET-sensitive MCF-7 cells (MCF-7-A2B1), results in ET resistance, …

The Role Of E-Liquid Constituents In E-Cigarette-Induced Cardiac Arrhythmia And Autonomic Imbalance., Cory Kucera

Electronic Theses and Dissertations

Introduction. Accumulating evidence indicates that exposure to electronic cigarettes (e-cigs) promotes sympathetic dominance and electrophysiologic instability in the heart, potentially culminating in arrhythmogenesis. E-liquids contain various formulations of nicotine and flavorings, but the effects of specific e-liquid constituents and their concentrations on e-cig-induced autonomic imbalance and electrical dysfunction are unresolved. To that end, we tested the hypothesis that e-cigs modify cardiac autonomic balance and ventricular arrhythmogenesis in mice dependent on e-liquid constituent type and concentration. Methods. Using a crossover design and a serial exposure regimen, ECG-telemetered male C57BL/6J mice underwent whole-body exposure to e-cig aerosols generated from e-liquids containing different …

Soluble Epoxide Hydrolase Inhibition: A Novel Therapeutic Strategy For Alcohol-Associated Liver Disease., Jeffrey Warner

Electronic Theses and Dissertations

Introduction Alcohol-associated liver disease (ALD) is a common chronic liver disease and healthcare burden, and a spectrum of pathologies ranging from steatosis to steatohepatitis, fibrosis, and alcohol-associated hepatitis (AH). Despite its prevalence, there are limited effective therapeutic options for the treatment of ALD/AH. Previous evidence suggested that inhibition of soluble epoxide hydrolase (sEH), a lipid metabolism enzyme which degrades beneficial metabolites of dietary polyunsaturated fatty acids, may be a beneficial strategy. The central hypothesis of the current dissertation is that sEH inhibition will ameliorate alcohol-associated liver injury and inflammation in mouse models of ALD. Methods To determine the efficacy of …

The Reinforcement Enhancing Effects Of Delta-9-Tetrahyrdrocannabinol (Thc) In Male And Female Rats, Kynah Walston

Electronic Theses and Dissertations

Cannabis is widely consumed by humans for pharmacological effects that are mediated by THC, though there is little evidence that THC is a primary reinforcer in non-human animal models. We hypothesized that THC may have potent reinforcement enhancing effects, comparable to other drugs (e.g., nicotine and caffeine) which are also widely consumed by humans, but difficult to establish as primary reinforcers in non-humans. In three experiments with male and female rats saccharin (SACC) or a visual stimulus (VS) served as reinforcers for operant behavior. We explored several pharmacological parameters of THC on responding for SACC or VS, including THC dose, …

Modulatory Effects Of Deacetylated Sialic Acids On Breast Cancer Resistance Protein-Mediated Multidrug Resistance And Receptor Tyrosine Kinase-Targeted Therapy, Isaac Tuffour

Electronic Theses and Dissertations

Multidrug resistance (MDR) remains a major challenge in cancer treatment, accounting for over 90% of chemotherapeutic failures. Cancers utilize sugar residues to engage in multidrug resistance. The underlying mechanism of action involving glycans, specifically the glycan sialic acid (Sia) and its various functional group alterations, has not been explored. ATP-binding cassette (ABC) transporter proteins, key proteins utilized by cancers to engage in MDR pathways, contain Sias in their extracellular domains. Modulating the expression of acetylated-Sias on Breast Cancer Resistance Protein (BCRP), a significant ABC transporter implicated in MDR, in lung and colon cancer cells directly impacted the ability of cancer …

Investigation Of Human N-Acetyltransferases (Nat1 And Nat2) Genetic Polymorphisms In Susceptibility To Aromatic Amine And Alkylaniline Genotoxicity., Mariam Habil

Electronic Theses and Dissertations

Arylamine N-acetyltransferases, NAT1 and NAT2, catalyze the detoxification and/or activation of carcinogens. Single nucleotide polymorphisms or SNPs result in different human NAT1 and NAT2 genotypes. We hypothesize that different NATs alleles will impact levels of N-acetylation, HPRT mutations, DNA damage and oxidative stress induced by carcinogens. NER-deficient Chinese hamster ovary (CHO) cells transfected with human CYP1A2 and NAT1*4, NAT1*14B, NAT2*4, NAT2*5B or NAT2*7B have been used to investigate N-acetylation of benzidine, β-naphthylamine (BNA), and 4, 4’-methylene bis (2-chloroaniline) (MOCA) as aromatic amines and 3,4-dimethylaniline (3,4-DMA) as one of alkylanilines and their associated toxicity. Our …

The Effect Of Volatile Organic Compounds On Endothelial Function And Atherogenesis., Samantha Mcfall

Electronic Theses and Dissertations

Volatile organic compounds (VOCs) are a group of pervasive air pollutants that are released into the atmosphere from both anthropogenic and environmental sources. Recent epidemiological studies suggest that exposure to various VOCs is associated with an increased risk of cardiovascular disease. However, the relationship between VOCs and cardiovascular disease is not well-studied. Using animal models and three select VOCs, benzene, xylene, and trichloroethylene, we studied the effects of VOCs on endothelial injury and benzene-induced atherogenesis. We found that exposure to benzene and xylene increased circulating endothelial microparticles, depleted progenitor cells, and increased platelet activation. Following the exposure to the representative …

Application Of Cannabidol To Ocular Pharmacokinetics And Pharmacodynamics., Alyssa Laun

Electronic Theses and Dissertations

Cannabidiol (CBD) is the most abundant non-psychotropic cannabinoid constituent of Cannabis sativa. CBD is potentially therapeutic for the eye through antioxidant, anti-inflammatory, and neuroprotective effects. However, the effect of CBD on intraocular pressure (IOP)- the major risk factor for glaucoma- is controversial and large variability exists in the literature. IOP is regulated through aqueous humor (AH) dynamics in trabecular meshwork (TM) tissues. Measurement of CBD in AH and correlation with effects on IOP would clarify what concentrations mediate changes to IOP. Therefore, the overall goal of this dissertation is to measure CBD in ocular tissues and correlate concentrations with …

Validation Of The 40 Hz Auditory Steady State Response As A Pharmacodynamic Biomarker Of Evoked Neural Synchrony, Muhammad Ummear Raza

Electronic Theses and Dissertations

Schizophrenia is a troubling and severe mental illness that is only incompletely treated by currently available drugs. New drug development is hindered by a scarcity of functionally relevant pharmacodynamic biomarkers that are translatable across preclinical and human subjects. Although psychosis is a major feature of schizophrenia, cognitive and negative symptoms determine the long-term functional outcomes for patients. Stimulus-evoked neural synchrony at gamma (~ 40 Hz) frequency plays an important role in the processing and integration of sensory information. Not surprisingly, schizophrenia patients show deficits in gamma oscillations. NMDA receptor (NMDAR) activation on fast-spiking parvalbumin-positive interneurons is deemed important for the …

Dibutyl Amine Detection, Quantification, And Removal With Iron(Ii)Tetrasulfophthalocyanine (Fetspc), Kyle Bittner

Electronic Theses and Dissertations

Pesticide testing is of practical interest in various areas of today’s world due to their prevalence and toxicity. These areas include agriculture, environmental, chemical plants, and many others. Herbicides, like Roundup, contain secondary amines such as glyphosate. The ability to detect secondary amines could offer a method for glyphosate detection in agricultural and environmental samples. Secondary amines can interact with metal complexes through electron charge transfer. Such interactions can cause a change in the metal’s electron configuration and energy state and can be seen in the UV-Vis spectrum. Metal phthalocyanines (MPc’s) and other organometallic complexes have been of interest for …