Pharmacology, Toxicology and Environmental Health Commons^™

Heightened Levels Of Microvesicle Particles Resulting From Combination Of Ethanol And Thermal Burn Injury, Chad Alan Brewer

Browse all Theses and Dissertations

Ethanol (EtOH), in combination with thermal burn injury, is a clinically significant problem resulting in an increase in morbidity and mortality due to acute multi-organ toxicity from excess systemic cytokine release. This intoxicated thermal burn affects close to 50% of the total numbers of hospital-admitted burn patients and currently has no standard treatment. However, using in vitro cellular and in vivo murine models, our group has provided data implicating the augmented production of the lipid mediator Platelet-activating factor (PAF) in keratinocytes in response to intoxicated thermal burn injury in the subsequent pathology. Of importance, our group has demonstrated that activation …

Replication Stress Induced By The Ribonucleotide Reductase Inhibitors Guanazole, Triapine, And Gemcitabine In Fission Yeast, Mashael Yahya A Alyahya

Browse all Theses and Dissertations

Replication stress can be produced by various exogenous or endogenous factors that perturb the movement of replication forks. To overcome the stress, the cells provoke the DNA replication checkpoint to mobilize several pathways to protect the forks, maintain genome integrity, and promote cell survival. Defects in the replication checkpoint cause forks collapse, leading to chromosomal DNA damage or cell death. Although the replication checkpoint is crucial for genome integrity in all eukaryotes, the underlying mechanisms remains to be fully understood. To investigate the mechanisms of DRC, hydroxyurea (HU), an established inhibitor of ribonucleotide reductase (RNR), has been widely used in …

Impaired Β-Cell Neogenesis In A Mouse Model Of Metabolic Syndrome, Modhi Abdullah Alshammari

Browse all Theses and Dissertations

Pancreatic islet β-cell plays an essential role in insulin release and hence glucose homeostasis. The maintenance of glucose homeostasis depends on β-cell ability to cope with enough insulin to fulfill metabolic and physiological demands. Adequate insulin release is the result of highly complex and dynamic interplays between acute changes in β- cell electrical activity, exocytosis and chronic adaptations in cellular function, volume, mass and proliferation. All of this appears modulated, to some extent, by the functional presence of Slc12a2 symporters, also known as Na+K+2Cl– cotransporter-1 (Nkcc1), which accumulates intracellular Cl– above its electrochemical equilibrium. Recent studies from our laboratory showed …

Ahr-Mediated Transcriptional Regulation Of The Human Immunoglobulin Hs1.2 Enhancer, Sydney White

Browse all Theses and Dissertations

The 3'IGHRR is thought to be responsible for the transcription of the immunoglobulin heavy chain (IGH) gene locus, which is essential for the production of antibodies. The human 3’IGHRR, which is duplicated in humans, contains the hs3, hs4, and hs1.2 enhancers. Additionally, the hs1.2 enhancer is polymorphic in humans and consists of a 53 bp invariant sequence that can be repeated one to four times. Previous experiments in a mouse and human B-cell line model have shown that the high affinity AhR ligand and environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can induce hs1.2 enhancer activity in an AhR-dependent manner. The AhR is …

The Effect Of Circadian Clock Modulation On Cisplatin Cytotoxicity, Nadeen Nibal Ahmad Anabtawi

Browse all Theses and Dissertations

Cisplatin is a DNA damage-based chemotherapeutic drug widely used to treat various types of cancers; however, the treatment's toxicity restricts its efficiency. Studies have shown that the circadian rhythm controls the DNA damage response and affects the repair pathways of cisplatin-induced DNA damage. Circadian clock modulation, therefore, has been proposed to be a potential mechanism for enhancing cisplatin tolerability. Here we used clock-enhancing molecules to evaluate the effect of pharmacological clock modulation on cisplatin cytotoxicity. Using cultured human cell lines, cisplatin cytotoxicity was found to be attenuated following treatment with circadian-enhancing molecules KS15 and SR8278. Moreover, the protein and mRNA …

Stress-Induced Senescence In Human Dermal Fibroblasts : Effects Of Creatine And Nicotinamide Post Stress Treatment, Venkata Sravya Arikatla

Browse all Theses and Dissertations

In skin connective tissue, dermal fibroblasts appear to be the most prevalent cell type. They are in charge of making the extracellular matrix that makes up the skin's connective tissue, and also involved in wound healing. Moreover, they produce Insulin-like growth factor-1 (IGF-1) which helps in activation of Insulin growth factor-1 receptor (IGF-1R). This receptor helps to control cell proliferation and responses to DNA-damaging substances such as UVB radiation, reactive oxygen species (ROS), and therapeutic drugs. According to our findings, lack of IGF-1 expression in the dermis of elderly patients due to fibroblast senescence (senescence is characterized by which cells …

The Protective Effects Of Mir-210 Modified Endothelial Progenitor Cells Released Exosomes In Hypoxia/Reoxygenation Injured Neurons, Sri Meghana Yerrapragada

Browse all Theses and Dissertations

Endothelial progenitor cells (EPCs) have been shown to provide beneficial effects on oxidative stress. Exosomes (EXs) released from these stem cells could be one of the major contributors, as they are known to convey the benefit of one cell to another cell via microRNAs (miRNA). At first, we determined that EPCs release more EXs when they are serum-starved for 48 hours., and by determining the microRNA-210 (miR-210) levels in the EXs, we found that miRNA is being transferred from cells to EXs. Meanwhile, miR-210 is gaining popularity in reducing elevated oxidative stress levels. In this study, we investigated the role …

Functions Of Atr Kinase In Terminally Differentiated Human Epidermal Keratinocyles And In Human Ex-Vivo Skin After Exposure To Ultraviolet B Radiation, Vivek Shashank Nag Gogusetti

Browse all Theses and Dissertations

The functions of Ataxia telangiectasia and Rad-3 related protein (ATR) is very much important in a cell, as it is a DNA damage response protein, which plays an important role in cell division, DNA repair and apoptosis. This protein helps in proliferation in the actively DNA dividing normal cells and in cancer cells. The functions of ATR in a proliferating cell are well studied and known to involve regulation of replication fork and cell cycle progression after DNA damage. Whereas, in a non-replicating cell, the functions of ATR are not so well known. In the human body, most of the …

Xeroderma Pigmentosum A Deficiency Results In Increased Generation Of Microvesicle Particles In Response To Ultraviolet B Radiation, Christian Lea Rajeshkumar

Browse all Theses and Dissertations

Xeroderma Pigmentosum is a genetic disorder in which ability to repair DNA damage such as from UV radiation is decreased. Nucleotide excision repair is known for repairing DNA damage caused by UV radiation and XPA plays a major role in recognizing and eliminating abnormal section of DNA. Therefore, XPA deficiency decreases repair efficiency of DNA. Of note, XPA deficiency is linked with photosensitivity. Microvesicle particles are membrane-bound particles which are released into the extracellular environment in response to multiple stimuli including the lipid Platelet activating factor (PAF). Previous studies have shown that XPA deficiency can induce increase production of reactive …

Insulin-Like Growth Factor-1 (Igf-1) Impacts P53-Regulated Gene Products In Uvb-Irradiated Human Keratinocytes And Skin Epidermis, Abdulrhaman Mohammed Mohammed Alkawwar

Browse all Theses and Dissertations

Skin cancer is the most prevalent human malignancy and is primarily caused by ultraviolet (UV) wavelengths of sunlight. However, the fact that most skin cancers occur in people over the age of 60 indicates that advantaged age is a second skin cancer risk factor. Why geriatric skin is prone to developing skin cancers is not clear, but several studies have shown that dermal fibroblasts in geriatric skin express lower levels of the hormone insulin-like growth factor-1 (IGF-1) than young adult skin and that deficient IGF-1 signaling negatively impacts how epidermal keratinocytes respond to UVB radiation. A major regulator of the …

Identification Of New Metabolic Mutations In The Fission Yeast Schizosaccharomyces Pombe That Sensitize The Cell To Hydroxyurea, Alaa Mahdi

Browse all Theses and Dissertations

Cancer is a life-threatening illness and innovative research is therefore required to fuel the development of new anti-cancer therapies. As an anti-proliferative drug, hydroxyurea (HU) has been used in the treatment of various neoplastic and non-neoplastic diseases such as sickle cell anemia, psoriasis, and viral infections. HU is a well-known inhibitor of ribonucleotide reductase (RNR), an enzyme that generates dNTPs for DNA replication and repair. In our genetic screen in fission yeast looking for mutants with defects in checkpoint response, we also found a set of mutants that are highly sensitive to HU but with a functional checkpoint response. It …

Multiple Genotoxic Agents Activate Atr Kinase Signaling In Quiescent Human Cells, Mariyyah Ahmed O. Madkhali

Browse all Theses and Dissertations

The ATR protein kinase is activated in response to DNA damage and other forms of genotoxic stress caused by both environmental carcinogens and anti-cancer drugs. However, much of our understanding of ATR kinase function is limited to proliferating cells in which DNA replication stress is the primary signal for ATR activation and where the major regulatory targets of ATR signaling are proteins involved in DNA synthesis and cell cycle progression. Here we have used HaCaT keratinocytes maintained in a non-replicating, quiescent state in vitro to examine how cell killing by different genotoxic agents is impacted by cell growth status and …

Topical Photodynamic Therapy Generates Microvesicle Particles, Oladayo Ayobami Oyebanji

Browse all Theses and Dissertations

Photodynamic therapy (PDT) involves the use of light at an appropriate wavelength acting on a photosensitizing chemical to cause cell death via generation of reactive oxygen species. PDT has been useful in the management of skin conditions (like acne, psoriasis) and cancers like superficial skin, esophageal and non-small cell lung cancers. In addition to these therapeutic effects, previous murine studies from our group have demonstrated that topical PDT induces immunosuppression in vivo. Thus, topical PDT of skin can generate systemic effects through unknown mechanisms. Our group showed that PDT induces an immunosuppressive effect which occurs partly via Platelet-Activating Factor Receptor …

Role Of Exercise In Macrophage Polarization Of Perivascular Adipose Tissue And Adipose Tissue Inflammation In Hypertensive Mice Model, Venkata Sai Usha Sri Polaki

Browse all Theses and Dissertations

Hypertension, also known as high blood pressure, is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. It can lead to severe health complications and increase the risk of heart disease, stroke, and sometimes death. Perivascular adipose tissue (PVAT) is known as the adipose tissue (AT) surrounding all the blood vessels and plays a critical role in the pathogenesis of the vascular disease. In vascular pathologies, PVAT increases in volume and becomes dysfunctional, with altered cellular composition and molecular characteristics. Macrophages have been found to accumulate in PVAT during hypertension, which might be involved …

Effects Of Creatine And Nicotinamide On Experimentally Induced Senescence In Dermal Fibroblasts, Avinash Satyanarayan Mahajan

Browse all Theses and Dissertations

Dermal fibroblasts provide structural support by producing collagen and other structural/support proteins beneath the epidermis. Fibroblasts also produce Insulin-like growth factor-1 (IGF-1), which binds to the IGF-1 receptors (IGF-1Rs) on keratinocytes to activate signaling pathways that regulate cell proliferation and cellular responses to genotoxic stressors like ultraviolet B radiation found in sunlight. Our group has determined that the lack of IGF-1 expression due to fibroblast senescence in the dermis of geriatric individuals is correlated with an increased incidence of skin cancer in geriatric patients. The present studies were designed to test the hypothesis that pro-energetics like creatine monohydrate and nicotinamide …

The Feeding Pattern Of C57bl/6j Mice, Yakshkumar Dilipbhai Rathod

Browse all Theses and Dissertations

The feeding pattern and control of energy intake in social mice are poorly understood. Here, we determined and quantify the normal nocturnal feeding pattern of group-housed male and female mice of the C57BL/6J genetic background fed a chow diet. Mice at 10 and 20weeks of age showed the expected age-dependent increase in lean and fat mass being them more pronounced in males. Under ad libitum conditions, male and female mice ate comparable amounts of food per unit of body weight irrespective of gender. The analysis of the feeding microstructure revealed that energy intake in females is the result of significantly …

Differing Functions Of Atr Kinase In Human Epidermal Keratinocytes Exposed To Ultraviolet B Radiation, Kavya Shaj

Browse all Theses and Dissertations

Ataxia-telangiectasia and Rad-3 related (ATR) is a DNA damage response protein kinase that is upregulated in various cancer cell types and has key roles in cell cycle progression, DNA repair and apoptosis. Small molecule ATR kinase inhibitors are of importance as antineoplastic agents because they sensitize cancer cells to DNA damaging chemotherapy drugs. However, only a few studies have looked at the effects of ATR kinase inhibitors on non-replicating cells, which constitute the majority of cells in the human body and have suggested an opposite, pro-apoptotic role for ATR kinase signaling in non-replicating cells in comparison to a pro-survival function …

Kinetics Of Microvesicle Particle Release In Keratinocytes, Pariksha Thapa

Browse all Theses and Dissertations

Microvesicle particles (MVPs) are subcellular particles that could be involved in inter-cellular communication because they carry various bioactive substances including cytokines. Previous studies from our lab has shown that that the lipid mediator Platelet-activating Factor (1-alkyl-2-acetyl-glycerophosphocholine; PAF) and ultraviolet B radiation (UVB) enhances the release of MVP in various cell types like primary keratinocytes, epithelial cell lines, and murine skin. We hypothesized that there may be synergistic increases in MVP release after combination of treatment of keratinocytes with UVB and PAF agonist (CPAF)/phorbol ester (PMA). The combination treatment significantly increases MVP and cytokine release at 4 to 8 hours time …

Effect Of Endothelial Progenitor Cell-Derived Exosomes On High Glucose And Hypoxia/ Reoxygenation-Induced Injury Of Astrocytes, Manasi Suchit Halurkar

Browse all Theses and Dissertations

In this study, we tested the protective effects of EPC-EXs (endothelial progenitor cell derived exosomes) and miR-126 EPC-EXs (microRNA-126 EPC-EXs) on the astrocytes injured by HG (high glucose) plus H/R (hypoxia/reoxygenation) model. At first, we determined the concentration and time dependent uptake of EPC-EXs by astrocytes. It was also found that the EPC-EXs were uptaken via macropinocytosis, caveolin-dependent and clathrin-mediated pathways in astrocytes. Furthermore, the astrocyte cell line was injured through the HG + H/R model. EXs, isolated by ultracentrifugation from the EPC culture supernatant were co-incubated with the injured cells. It was found that EPC-EXs and miR-126 EPC-EXs decrease …

Interaction Of Na+/K+ Atpase With Bcl-2 Proteins: Isolated Enzyme Vs Epithelial Cell Extracts, Chandra Kumar Maharjan

Browse all Theses and Dissertations

The nearly complete inhibition of Na+/K+ ATPase (NKA) in fetal human lens (FHL) epithelial cells by chelerythrine (CHE), a Bcl-2 homology (BH)3-mimetic quaternary benzophenanthridine alkaloid was proposed to be the consequence of CHE binding at a BH1-like hydrophobic groove at the cytosolic aspect of NKA. This conclusion was based on in silico analysis showing at least two motifs in the N-terminal domain of NKA’s a1 subunit- i) aa 59-71 (ARAAEILARDGPN) and ii) aa 42-48 (DELHRKY) homologous to the BH1 and BH3 motifs of Bcl-2 (B-cell lymphoma) respectively, leading to a novel hypothesis that NKA could interact with these proteins by …

The Role Of Nkcc2a On The Nervous System Activity, Kavya Annu

Browse all Theses and Dissertations

The NKCC2A is a splice variant of the Na+K+2Cl- co-transporter 2 (Slc12a1), which is abundantly expressed in macula densa and in the apical membrane of the tubular cells in the kidney. Most of our knowledge regarding NKCC2 function is limited to the kidney, the organ where NKCC2 is abundantly expressed. However, recent studies have demonstrated that NKCC2 is also expressed in extra-renal tissues. This study was designed to determine if NKCC2A, a splice variant of NKCC2 has an impact on behavior and nervous system activity of mice. To these ends, we used mice (wild type, WT), lacking a single or …

Role Of Angiotensin Ii Type 1a Receptors On Renal And Urinary Angiotensin Converting Enzyme 2 (Ace2) And Neprilysin (Nep) In The Two-Kidney One-Clip (2k1c) Model Of Renovascular Hypertension, Laale F. Alawi

Browse all Theses and Dissertations

Activation of the renin angiotensin system (RAS) and increased formation of angiotensin (Ang) II contribute to the progression of chronic kidney disease (CKD). Ang II, the major biologically active peptide of RAS, acts mainly as a vasoconstrictor through binding to the Ang II type 1 receptor (AT1R), which leads to increased blood pressure, fluid retention, and aldosterone secretion. The actions of Ang II are antagonized by its conversion to the vasodilator Ang (1-7), partly generated by the action of angiotensin converting enzyme 2 (ACE2) and/or neprilysin (NEP). The metalloprotease ADAM17 has a crucial role in the shedding of renal ACE2 …

Behavior Of Gold Nanoparticles In Physiological Environment And The Role Of Agglomeration And Fractal Dimension, Rose Cooper

Browse all Theses and Dissertations

The Present study was designed to examine the role of agglomeration, density and the resulting fractal dimension of nanomaterials in cell culture media. Studies were completed on the kinetics and the process of agglomeration, as well as how to calculate fractal dimensions. The correlation of such complex agglomeration patterns of nanomaterials in culture media, their translocation into cells, and toxic effects were observed. Our results showed that smaller primary particles agglomerated at an accelerated rate when compared to the larger primary particles. They also demonstrated increased cellular uptake, but exhibited lower fractal dimensions. The larger primary particle agglomerates displayed obvious …

Characterization Of Small Conductance Calcium-Activated Potassium Channels In A Human Lens Epithelium Cell Line (B3), Wedad Ali Saqar

Browse all Theses and Dissertations

Small conductance calcium-activated potassium (SK) channels belong to the family of K+ channels. They play a significant role in cell volume regulation and in lens homeostasis, and thus are associated with cataract formation. This study was designed to demonstrate the presence of the four different isoforms of SK channels (SK1, SK2, SK3, and SK4) in human lens epithelial (HLE)-B3 cell line using Western blot (WB), immunofluorescence (IF), and reverse transcriptase coupled to the polymerase chain reaction (RT-PCR). Cataract formation involves SK-mediated K+ loss and gain of Na+ ions by lens cells. Further, it has been shown in previous studies that …

Role Of Bumetanide On Insulin Secretion, Mohammed Mashari Almutairi

Browse all Theses and Dissertations

Insulin secretion depends on the electrical properties of the ß-cells in pancreatic islets. The consensus mechanism of insulin secretion involves glucose-stimulated metabolic increase in the ATP/ADP ratio. This increase closes ATP-sensitive K+ (KATP) channels resulting in ß-cell plasma membrane depolarization, which in turn activates voltage-dependent Ca2+ channels further resulting in Ca2+ influx and release of insulin stored in granules. In addition to this well-known consensus mechanism, insulin secretion also depends on electrogenic efflux of Cl- ions. The Na+K 2Cl- cotransporters (NKCCs) maintain the intracellular concentration of Cl- ([Cl-]i) at values higher than those predicted at thermodynamic equilibrium. This distribution of …

Chronic Swim Stress Attenuates Endocrine Response And Improves Cardiac Function In Mice Lacking The Angiotensin Ii Type 1a Receptor, Najat Khalifa Almahroug

Browse all Theses and Dissertations

Stress is a stimulus that causes an often abrupt but always large change in autonomic activity and hormone secretion. Angiotensin II (AngII) is one of the main neurohormonal mediators that are stimulated by stress. AngII mediates most of its relevant biological effects via AngII type1 receptor (AT1R) activation. Stress increases tissue and circulating levels of Ang II which contributes to stimulation of adrenal AT1R, mediating stressinduced hormone release. Ang II through the activation of AT1R not only elevates blood pressure but also has a patho-physiological relevance in cardiac remodeling. The goal of this study was to assess the influence of …

Enhanced Angiotensin Ii-Induced Cardiac And Aortic Remodeling In Ace2 Knockout Mice, Mahmoud Alghamri

Browse all Theses and Dissertations

Activation of the renin angiotensin system (RAS) is a well-known driving force, governing the aggravation and progression of CVD and associated target organ damage. Angiotensin (Ang) converting enzyme 2 (ACE2), a new member within the RAS family, was first cloned from the ventricle of patient with heart failure. ACE2 was shown to be upregulated under pathological conditions. We hypothesize that loss of ACE2 negatively affects cardiac function and exacerbates hypertrophic cardiomyopathy and aortic remodeling in response to Ang II. Eight weeks old ACE2 knock out (KO) and wild type (WT) mice were infused with Ang II s.c. (1000 ng/kg/min for …

Response Of Monovalent Cation Transporters To Pro-Apoptotic Protein Kinase C Modulators In Human Lens Epithelial Cells, Michael Anthony Lepera

Browse all Theses and Dissertations

Protein kinase inhibition by staurosporine causes apoptotic volume decrease involving potassium (K) channels in immortalized human B3 lens epithelial cells (LECs). Here, the effect of two pro-apoptotic protein kinase C (PKC) inhibitors [12-O-tetradecanoyl-phorbol-13-acetate (TPA) and chelerythrine (CET)] were studied on membrane K transport in a fetal human LEC line (FHL124) by western blotting, immunofluorescence, ion flux, ATP, apoptosis, and biotinylation assays. Long term TPA exposure (0-6 h) inhibited 75% of Na-K-2Cl cotransport (NKCC). In contrast, short term (0-20 min) exposure to 50 μM CET reduced Na/K pump and NKCC by >90% and >70%, respectively, without retrieval from the membrane into …

Differentiation Of Megakaryocytes/Platelets And Neurons From Human Endometrial Stromal Progenitor Cells, Jinju Wang

Browse all Theses and Dissertations

Human endometrium is a high dynamic tissue that contains stem/progenitor cells. These endometrial stromal progenitor cells (hESCs) have been differentiated into a number of mesodermal lineages. There is limited information on differentiating hESCs into neurons, and no information on differentiating hESCs into megakaryocytes (MKs) and platelets (PLTs). The aim of this work was to investigate the possibility of differentiating hESCs into two distinct lineages: MKs, with subsequent PLT formation, and neurons.

We isolated hESCs from human endometrial tissue and cultured the cells for 4-6 passages. Before each differentiation experiment, the purity of hESCs was confirmed by flow cytometry analysis which …

Response Of Neuroinflammatory And Neurodegenerative Markers Following Sub-Lethal Sarin Exposure And Subsequent Treatment Via An In-Vivo Caspase Inhibitor, Douglas F. Chmura

Browse all Theses and Dissertations

Organophosphorus nerve agents are amongst the most deadly chemical compounds ever synthesized. Sarin is an organophosphate (OP) ester that irreversibly forms a phosphoester bond at the active site of acetylcholinesterase and thereby induces a rapid and lethal cholinergic crisis. It remains an active threat to vulnerable civilian populations due to its ease of synthesis and known use by rogue nations and terrorist groups. Death is the most extreme consequence of sarin toxicity. Current treatments fail to provide protection against progressive cognitive impairments years after mild exposure. Q-VD-OPh is an in-vivo caspase inhibitor with potent anti-apoptotic and anti-inflammatory properties. In this …