Cellular and Molecular Physiology Commons^™

Modulating Beta-Cardiac Myosin Function At The Molecular And Tissue Levels, Wanjian Tang, Cheavar A. Blair, Shane D. Walton, András Málnási-Csizmadia, Kenneth S. Campbell, Christopher M. Yengo

Physiology Faculty Publications

Inherited cardiomyopathies are a common form of heart disease that are caused by mutations in sarcomeric proteins with beta cardiac myosin (MYH7) being one of the most frequently affected genes. Since the discovery of the first cardiomyopathy associated mutation in beta-cardiac myosin, a major goal has been to correlate the in vitro myosin motor properties with the contractile performance of cardiac muscle. There has been substantial progress in developing assays to measure the force and velocity properties of purified cardiac muscle myosin but it is still challenging to correlate results from molecular and tissue-level experiments. Mutations that cause …

Ionic Regulation Of Critical Cellular Processes In Non-Excitable Cells, Brandon M. Franklin

Theses and Dissertations--Biology

There are long-standing hypotheses that endogenous ion currents act to control cell dynamics in development, wound healing and regeneration. However, the mechanisms employed by cells to detect the electric field (EF) and translate it into a discernable message to drive specific cell behaviors, such as migration, proliferation and differentiation, are not well understood. A better understanding of how cells are able to sense EFs and react to them is vital to understanding physiological mechanisms are involved in regeneration. Ion channel signaling provides a reasonable suspect for mediating these effects based on their documented involvement in proliferation, migration and differentiation.

To …

The Mechanical Properties Of Non-Failing And Failing Human Myocardium, Cheavar A. Blair

Theses and Dissertations--Physiology

Heart failure is a clinical syndrome that manifests when there are structural and functional impairments to the heart that reduces the ability of the ventricles to fill or eject blood. The syndrome affects ~6 million Americans and is responsible for nearly 300,000 deaths annually. At the core of the syndrome are dysfunctional sarcomeres, the machinery that drives cardiac contraction and relaxation. By assessing the mechanical properties of human cardiac tissue, the information provided in this dissertation will provide data that demonstrates how sarcomeric dysfunction contributes to heart failure in the left and right ventricles. Additionally, these data will supply information …

Assessment Of Bovine Vascular Serotonin Receptor Populations And Transport Of Ergot Alkaloids In The Small Intestine, Miriam A. Snider

Theses and Dissertations--Animal and Food Sciences

Prior work using a contractility bioassay determined that the serotonin (5-HT) receptor subtype 5-HT_2A is present in bovine lateral saphenous veins and plays a role in ergot alkaloid-induced vascular contraction in steers grazing endophyte-infected (Epichloë coenophiala) tall fescue (Lolium arundinaceum). A study was conducted to determine what 5-HT receptors are involved in vasoconstriction of bovine gut vasculature. The findings of this study indicate that 5-HT_2A is present and may play a role in ergot alkaloid induced vasoconstriction. A second study was conducted to determine if ergot alkaloids were transported in the small intestine. The …

Differential Activity And Content Of High-Affinity Glutamate Transporters, Content Of Their Regulatory Proteins, And Capacity For Glutamine And Glutathione Synthesis In Tissues Of Finished Versus Growing Steers, Jing Huang

Theses and Dissertations--Animal and Food Sciences

Improvement of feeding regimens for production animals has been hindered by a lack of fundamental knowledge about how the capacity to regulate nutrient absorption across cell membranes affects the function of nutrient metabolizing enzymes. The objective is to determine if the activities and protein content of system X^-_AG glutamate transporter, its regulatory protein (GTRAP3-18 and ARL6IP1), glutamine synthetase (GS) and glutathione (GSH) content, changes in liver (Experiment 1), longissimus dorsi (LM) and subcutaneous adipose tissue (SF) (Experiment 2) as beef steers transitioned from predominantly-lean (growing) to -lipid (finished) tissue accretion phases. In liver (Experiment 1), system X^{- …}

Rad Gtpase: Identification Of Novel Regulatory Mechanisms And A New Function In Modulation Of Bone Density And Marrow Adiposity, Catherine Nicole Kaminski Withers

Theses and Dissertations--Molecular and Cellular Biochemistry

The small GTP-binding protein Rad (RRAD, Ras associated with diabetes) is the founding member of the RGK (Rad, Rem, Rem2, and Gem/Kir) family that regulates voltage-dependent calcium channel function. Given its expression in both excitable and non-excitable cell types, the control mechanisms for Rad regulation and the potential for novel functions for Rad beyond calcium channel modulation are open questions. Here we report a novel interaction between Rad and Enigma, a scaffolding protein that also binds to the E3 ubiquitin ligase Smad ubiquitin regulatory factor 1 (Smurf1). Overexpression of Smurf1, but not …

Profiling The Action Of Acetylcholine In The Drosophila Melanogaster Larval Model: Heart, Behavior, And The Development And Maintenance Of Sensorimotor Circuits, Cole A. Malloy

Theses and Dissertations--Biology

Understanding the role of various chemical messengers in altering behaviors and physiological processes is a common goal for scientists across multiple disciplines. The main focus of this dissertation is on characterizing the action of an important neurotransmitter, acetylcholine (ACh), modulating larval Drosophila melanogaster neural circuits and heart. In this dissertation, I provide important insights into the mechanisms by which ACh influences the formation and performance of select neural circuits, while also revealing significant details regarding its role in additional physiological functions, including cardiac pace making. In Chapter 1, I provide a general overview of ACh action in mammals and flies …

The Effect Of Cold On The Physiology Of Drosophila Larva Heart And On Synaptic Transmission At Crayfish Neuromuscular Junctions, Yuechen Zhu

Theses and Dissertations--Biology

Ectothermic animals are susceptible to temperature changes such as cold shock with seasons. To survive through a cold shock, ectotherms have developed unique strategies. My interest is focusing on the physiological function of during cold shock and prolonged cold exposure in the fruit fly (Drosophila melanogaster) and crayfish (Procambarus clarkii). I used Drosophila melanogaster as a model system to investigate cardiac function in response to modulators (serotonin, acetylcholine, octopamine, dopamine and a cocktail of modulators) in acute cold shock and chronic cold shock conditions as possible mechanism to regulate heart rate in the cold. To examine if the dampened heart …

Cellular And Subcellular Oxidative Stress Parameters Following Severe Spinal Cord Injury, Nishant P. Visavadiya, Samir P. Patel, Jenna L. Vanrooyen, Patrick G. Sullivan, Alexander G. Rabchevsky

Spinal Cord and Brain Injury Research Center Faculty Publications

The present study undertook a comprehensive assessment of the acute biochemical oxidative stress parameters in both cellular and, notably, mitochondrial isolates following severe upper lumbar contusion spinal cord injury (SCI) in adult female Sprague Dawley rats. At 24 h post-injury, spinal cord tissue homogenate and mitochondrial fractions were isolated concurrently and assessed for glutathione (GSH) content and production of nitric oxide (NO^•), in addition to the presence of oxidative stress markers 3-nitrotyrosine (3-NT), protein carbonyl (PC), 4-hydroxynonenal (4-HNE) and lipid peroxidation (LPO). Moreover, we assessed production of superoxide (O₂^•-) and hydrogen peroxide (H₂O …

Quantitative Mass Spectrometry Reveals Changes In Histone H2b Variants As Cells Undergo Inorganic Arsenic-Mediated Cellular Transformation, Matthew Rea, Tingting Jiang, Rebekah Eleazer, Meredith Eckstein, Alan G. Marshall, Yvonne N. Fondufe-Mittendorf

Molecular and Cellular Biochemistry Faculty Publications

Exposure to inorganic arsenic, a ubiquitous environmental toxic metalloid, leads to carcinogenesis. However, the mechanism is unknown. Several studies have shown that inorganic arsenic exposure alters specific gene expression patterns, possibly through alterations in chromatin structure. While most studies on understanding the mechanism of chromatin-mediated gene regulation have focused on histone post-translational modifications, the role of histone variants remains largely unknown. Incorporation of histone variants alters the functional properties of chromatin. To understand the global dynamics of chromatin structure and function in arsenic-mediated carcinogenesis, analysis of the histone variants incorporated into the nucleosome and their covalent modifications is required. Here …

Calcitriol Increases Ceramide, Diacylglycerol, And Expression Of Genes Involved In Lipid Packaging In Skeletal Muscle, Grace Elizabeth Jefferson

Theses and Dissertations--Kinesiology and Health Promotion

Background: Vitamin D is crucial for skeletal muscle function. 25-hidroxyvitamin D (25(OH)D) has been correlated with skeletal muscle mass and intramyocellular lipid (IMCL) content. The purpose of this study was to understand how calcitriol, the active vitamin D metabolite, directly affects myocellular size and lipid partitioning.

Methods: C₂C₁₂ myotubes were treated with calcitriol (100nM) or vehicle control for 24 or 96 h. Myotube diameter and protein synthesis rate were measured to determine effects of calcitriol on myocellular size. Intramyocellular triacylglycerol (IMTG), diacylglycerol (DAG), and ceramide content were measured by LC/MS. Expression of genes involved in lipid packaging …

Ppap2b Expression Limits Lesion Formation In Murine Models Of Atherosclerosis, Paul A. Mueller

Theses and Dissertations--Physiology

Coronary artery disease (CAD) is the leading cause of death in both men and women worldwide and is defined as a narrowing of the coronary arteries due to accumulation of atherosclerotic plaques. Genome-wide association studies have identified risk loci within the gene PPAP2B that confers increased risk of developing CAD. Evidence suggests these aforementioned SNPs are regulating PPAP2B expression in a cis-manner through the interruption of transcription factor binding sites. PPAP2B encodes the lipid phosphate phosphatase 3 enzyme that plays a key role in degrading bioactive lysophosphatidic acid (LPA). LPA has a plethora of effects on vascular tissue and is …

Targeting The Wnt/Β-Catenin Signaling Pathway In Liver Cancer Stem Cells And Hepatocellular Carcinoma Cell Lines With Fh535, Roberto Gedaly, Roberto Galuppo, Michael F. Daily, Malay B. Shah, Erin Colleen Maynard, Changguo Chen, Xiping Zhang, Karyn A. Esser, Donald A. Cohen, B. Mark Evers, Jieyun Jiang, Brett T. Spear

Surgery Faculty Publications

Activation of the Wnt/β-catenin pathway has been observed in at least 1/3 of hepatocellular carcinomas (HCC), and a significant number of these have mutations in the β-catenin gene. Therefore, effective inhibition of this pathway could provide a novel method to treat HCC. The purposed of this study was to determine whether FH535, which was previously shown to block the β-catenin pathway, could inhibit β-catenin activation of target genes and inhibit proliferation of Liver Cancer Stem Cells (LCSC) and HCC cell lines. Using β-catenin responsive reporter genes, our data indicates that FH535 can inhibit target gene activation by endogenous and exogenously …

Trpa1 Channels In Cochlear Supporting Cells Regulate Hearing Sensitivity After Noise Exposure, Alejandra C. Velez-Ortega

Theses and Dissertations--Physiology

TRPA1 channels are sensors for noxious stimuli in a subset of nociceptive neurons. TRPA1 channels are also expressed in cells of the mammalian inner ear, but their function in this tissue remains unknown given that Trpa1^–/– mice exhibit normal hearing, balance and sensory mechanotransduction. Here we show that non-sensory (supporting) cells of the hearing organ in the cochlea detect tissue damage via the activation of TRPA1 channels and subsequently modulate cochlear amplification through active cellshape changes.

We found that cochlear supporting cells of wild type but not Trpa1^–/– mice generate inward currents and robust long-lasting Ca²⁺ responses …

Transmural Heterogeneity Of Cellular Level Cardiac Contractile Properties In Aging And Heart Failure, Premi Haynes

Theses and Dissertations--Physiology

The left ventricle of the heart relaxes when it fills with blood and contracts to eject blood into circulation to meet the body’s metabolic demands. Dysfunction in either relaxation or contraction of the left ventricle can lead to heart failure. Transmural heterogeneity is thought to contribute to normal ventricular wall motion but it is not well understood how transmural modifications affect the failing left ventricle. The overall hypothesis of this dissertation is that normal left ventricles exhibit transmural heterogeneity in cellular level contractile properties and with aging and heart failure there are region-specific changes in cellular level contractile mechanisms.

Age …

The Effects Of Hydrostatic Pressure On Early Endothelial Tubulogenic Processes, Ryan M. Underwood

Theses and Dissertations--Biomedical Engineering

The effects of mechanical forces on endothelial cell function and behavior are well documented, but have not been fully characterized. Specifically, fluid pressure has been shown to elicit physical and chemical responses known to be involved in the initiation and progression of endothelial cell-mediated vascularization. Central to the process of vascularization is the formation of tube-like structures. This process—tubulogenesis—is essential to both the physiological and pathological growth of tissues. Given the known effects of pressure on endothelial cells and its ubiquitous presence in the vasculature, we investigated pressure as a magnitude-dependent parameter for the regulation of endothelial tubulogenic activity. To …

The Cardiac L-Type Calcium Channel Distal Carboxyl- Terminus Auto-Inhibition Is Regulated By Calcium, Shawn M. Crump

Theses and Dissertations--Physiology

The L-type calcium channel (LTCC) provides trigger Ca²⁺ for sarcoplasmic reticulum Ca²⁺-release and LTCC function is influenced by interacting proteins including the LTCC Distal Carboxyl-terminus (DCT) and calmodulin. DCT is proteolytically cleaved, and re-associates with the LTCC complex to regulate calcium channel function. DCT reduces LTCC barium current (IBa,L) in reconstituted channel complexes, yet the contribution of DCT to ICa,L in cardiomyocyte systems is unexplored. This study tests the hypothesis that DCT attenuates cardiomyocyte ICa,L. We measured LTCC current and Ca²⁺ transients with DCT co-expressed in murine cardiomyocytes. We also heterologously co-expressed DCT and CaV1.2 constructs …

Enkephalin-Encoding Herpes Simplex Virus-1 Decreases Inflammation And Hotplate Sensitivity In A Chronic Pancreatitis Model, Hong Yang, Terry A. Mcnearney, Rong Chu, Ying Lu, Yong Ren, David C. Yeomans, Steven P. Wilson, Karin N. Westlund

Physiology Faculty Publications

Background: A chronic pancreatitis model was developed in young male Lewis rats fed a high-fat and alcohol liquid diet beginning at three weeks. The model was used to assess time course and efficacy of a replication defective herpes simplex virus type 1 vector construct delivering human cDNA encoding preproenkephalin (HSV-ENK).

Results: Most surprising was the relative lack of inflammation and tissue disruption after HSV-ENK treatment compared to the histopathology consistent with pancreatitis (inflammatory cell infiltration, edema, acinar cell hypertrophy, fibrosis) present as a result of the high-fat and alcohol diet in controls. The HSV-ENK vector delivered to the pancreatic surface …