Medical Physiology Commons^™

Molecular Determinants Of Trp Channel Gating, Briar J. Bell

Theses and Dissertations (ETD)

Transient Receptor Potential (TRP) ion channels are a family of proteins that contribute to a myriad of physiological functions. They have been extensively studied since their discovery 35 years ago; however, there are still many questions regarding the mechanisms by which they function. This family of proteins is characterized by a generally shared structure: an intracellular N terminus featuring ankyrin repeats, six transmembrane helices including the pore domain, a re-entrant loop and TRP helix, and an intracellular C terminus with varying structure. Each of these regions has been implicated in the regular function of TRPs, while mutations that alter trafficking …

Validating Osteological Correlates For The Hepatic Piston In The American Alligator (Alligator Mississippiensis), Clinton A. Grand Pre, William Thielicke, Raul E. Diaz, Brandon P. Hedrick, Ruth M. Elsey, Emma R. Schachner

School of Graduate Studies Faculty Publications

Unlike the majority of sauropsids, which breathe primarily through costal and abdominal muscle contractions, extant crocodilians have evolved the hepatic piston pump, a unique additional ventilatory mechanism powered by the diaphragmaticus muscle. This muscle originates from the bony pelvis, wrapping around the abdominal viscera, extending cranially to the liver. The liver then attaches to the caudal margin of the lungs, resulting in a sub-fusiform morphology for the entire ‘‘pulmo-hepatic-diaphragmatic’’ structure. When the diaphragmaticus muscle contracts during inspiration, the liver is pulled caudally, lowering pressure in the thoracolumbar cavity, and inflating the lungs. It has been established that the hepatic piston …

Human Airway Mucociliary Tissue Cultures Chronically Exposed To E-Cigarette Vapors Exhibit Altered Cell Populations And Increased Secretion Of Immunomodulatory Cytokines, Vanessa Pizutelli, Vincent Manna, Shannon Dwyer, Salvatore Caradonna

Rowan-Virtua Research Day

Vape-pens or electronic cigarettes (e-cigarettes) are handheld battery powered devices that use a vape-liquid to produce a vapor that is inhaled by the user. The active ingredients in commercial vape-liquids are commonly nicotine, tetrahydrocannabinol or cannabidiol. A consequence of the rise in e-cigarette usage was the 2019 emergence of a vaping-induced respiratory disease denoted ‘e-cigarette or vaping use-associated lung injury’ (EVALI). One of the suspected causes of EVALI is Vitamin E Acetate (VEA), which was found to be a diluent in certain illicit tetrahydrocannabinol vape-pens, whereas nicotine is commonly diluted in equal parts propylene glycol and vegetable glycerin (PG:VG). The …

Nicotinamide Riboside And Beta-Hydroxybutyrate Activate Parallel Pathways For C. Elegans Lifespan Extension, Mckenzie Peters

Undergraduate Honors Theses

Supplementation with nicotinamide riboside (NR), a form of vitamin B3 and a precursor of nicotinamide adenine dinucleotide (NAD⁺) extends lifespan in the nematode C. elegans and delays aging-related pathologies in mammals. During aging, levels of NAD⁺ decline causing metabolic dysfunction and oxidative damage. Studies in C. elegans found that when NR was administered during larval development it induced the mitochondrial unfolded protein response (UPR^mt), which is frequently associated with lifespan extension. Both calorie restriction (CR) and ketogenic diets (KD) have been shown to extend lifespan, in part through increasing NAD⁺ and through increasing levels …

Substrate Stiffness: A Mechanical Determinant Of Endothelial Phenotype, Sunita Subedi Paudel

Graduate Theses and Dissertations (2019 - present)

Endothelial cells (ECs) adhere to their neighboring cells via adherens and tight junctions, and to the basement membrane via focal adhesions. These structural elements are constantly remodeling i.e., even in a quiescent state, cells are in constant motion. ECs sense the stiffness of the basement membrane, and this stiffness is a physiological signal that control the cellular phenotype. Whereas the normotensive pulmonary circulation has a substrate stiffness that is ~1.25-4 kPa, vascular remodeling in pulmonary arterial hypertension (PAH) increases substrate stiffness to ~30 kPa. The impact that this increase in substrate stiffness has no cell size, shape, and speed was …

A Design, Development, And Evaluation Of Bio-Patch For Myocardial Tissue Repair, Yaya Zhang

Theses and Dissertations (ETD)

Introduction. Ischemic heart disease (IHD) is a major concern of human health issue. The structural repair and functional recovery of injured hearts is a major challenge in the clinical setting. Preclinical studies over last 10 years have demonstrated the potential of using stem cells to treat IHD, but the efficacy of this therapy is jeopardized by uncontrollable migration and low survival of the injected stem cells. An approach based on tissue engineering enabling target-specific stem cell delivery such as cardiac patches has emerged as an alternative solution for stem cell therapy for IHD. It employs scaffold materials to engulf various …

Massive Loss Of Proprioceptive Ia Synapses In Rat Spinal Motoneurons After Nerve Crush Injuries In The Postnatal Period, Ariadna Arbat-Plana, Sara Bolívar, Xavier Navarro, Esther Udina, Francisco J. Alvarez

Neuroscience, Cell Biology & Physiology Faculty Publications

Peripheral nerve injuries (PNIs) induce the retraction from the ventral horn of the synaptic collaterals of Ia afferents injured in the nerve, effectively removing Ia synapses from α-motoneurons. The loss of Ia input impairs functional recovery and could explain, in part, better recovery after PNIs with better Ia synaptic preservation. Synaptic losses correlate with injury severity, speed, and efficiency of muscle reinnervation and requires ventral microglia activation. It is unknown whether this plasticity is age dependent. In neonates, axotomized motoneurons and sensory neurons undergo apoptosis, but after postnatal day 10 most survive. The goal of this study was to analyze …

Fast Blue And Cholera Toxin-B Survival Guide For Alpha-Motoneurons Labeling: Less Is Better In Young B6sjl Mice, But More Is Better In Aged C57bl/J Mice, Hasan Farid, Weston B. Gleford, Lori L. Goss, Teresa L. Garrett, Sherif M. Elbasiouny

Neuroscience, Cell Biology & Physiology Faculty Publications

Fast Blue (FB) and Cholera Toxin-B (CTB) are two retrograde tracers extensively used to label alpha-motoneurons (α-MNs). The overall goals of the present study were to (1) assess the effectiveness of different FB and CTB protocols in labeling α-MNs, (2) compare the labeling quality of these tracers at standard concentrations reported in the literature (FB 2% and CTB 0.1%) versus lower concentrations to overcome tracer leakage, and (3) determine an optimal protocol for labeling α-MNs in young B6SJL and aged C57Bl/J mice (when axonal transport is disrupted by aging). Hindlimb muscles of young B6SJL and aged C57Bl/J mice were intramuscularly …

Capture At The Er-Mitochondrial Contacts Licenses Ip, Máté Katona, Ádám Bartók, Zuzana Nichtova, György Csordás, Elena Berezhnaya, David Weaver, Arijita Ghosh, Péter Várnai, David I. Yule, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Endoplasmic reticulum-mitochondria contacts (ERMCs) are restructured in response to changes in cell state. While this restructuring has been implicated as a cause or consequence of pathology in numerous systems, the underlying molecular dynamics are poorly understood. Here, we show means to visualize the capture of motile IP3 receptors (IP3Rs) at ERMCs and document the immediate consequences for calcium signaling and metabolism. IP3Rs are of particular interest because their presence provides a scaffold for ERMCs that mediate local calcium signaling, and their function outside of ERMCs depends on their motility. Unexpectedly, in a cell model with little ERMC Ca2+ coupling, IP3Rs …

Motoneuron Excitability Dysfunction In Als: Pseudo-Mystery Or Authentic Conundrum?, Sherif M. Elbasiouny

Neuroscience, Cell Biology & Physiology Faculty Publications

In amyotrophic lateral sclerosis (ALS), abnormalities in motoneuronal excitability are seen in early pathogenesis and throughout disease progression. Fully understanding motoneuron excitability dysfunction may lead to more effective treatments. Yet decades of research have not produced consensus on the nature, role or underlying mechanisms of motoneuron excitability dysfunction in ALS. For example, contrary to Ca excitotoxicity theory, predictions of motoneuronal hyper-excitability, normal and hypo-excitability have also been seen at various disease stages and in multiple ALS lines. Accordingly, motoneuron excitability dysfunction in ALS is a disputed topic in the field. Specifically, the form (hyper, hypo or unchanged) and what role …

Non-Invasive Transcutaneous Spinal Dc Stimulation As A Neurorehabilitation Als Therapy In Awake G93a Mice: The First Step To Clinical Translation, Morgan M. Highlander, Sherif M. Elbasiouny

Neuroscience, Cell Biology & Physiology Faculty Publications

Spinal direct current stimulation (sDCS) modulates motoneuron (MN) excitability beyond the stimulation period, making it a potential neurorehabilitation therapy for amyotrophic lateral sclerosis (ALS), a MN degenerative disease in which MN excitability dysfunction plays a critical and complex role. Recent evidence confirms induced changes in MN excitability via measured MN electrophysiological properties in the SOD1 ALS mouse during and following invasive subcutaneous sDCS (ssDCS). The first aim of our pilot study was to determine the clinical potential of these excitability changes at symptom onset (P90-P105) in ALS via a novel non-invasive transcutaneous sDCS (tsDCS) treatment paradigm on un-anesthetized SOD1-G93A mice. …

Suppression Of Store-Operated Calcium Entry Channels And Cytokine Release By Cannabinoids, J. Ashot Kozak

Neuroscience, Cell Biology & Physiology Faculty Publications

No abstract provided.

The Role Of Microglia In Neuroinflammation Of The Spinal Cord After Peripheral Nerve Injury, Tana S. Pottorf, Travis M. Rotterman, William M. Mccallum, Zoë A. Haley-Johnson, Francisco J. Alvarez

Neuroscience, Cell Biology & Physiology Faculty Publications

Peripheral nerve injuries induce a pronounced immune reaction within the spinal cord, largely governed by microglia activation in both the dorsal and ventral horns. The mechanisms of activation and response of microglia are diverse depending on the location within the spinal cord, type, severity, and proximity of injury, as well as the age and species of the organism. Thanks to recent advancements in neuro-immune research techniques, such as single-cell transcriptomics, novel genetic mouse models, and live imaging, a vast amount of literature has come to light regarding the mechanisms of microglial activation and alluding to the function …

Lysosomal Zn 2+ Release Triggers Rapid, Mitochondria-Mediated, Non-Apoptotic Cell Death In Metastatic Melanoma, Wanlu Du, Mingxue Gu, Meiqin Hu, Timothy Nold, Prateeksunder Pinchi, Wei Chen, Michael Ryan, Ahmed Bannaga, Haoxing Xu

Medical Student Research Symposium

During tumor progression, lysosome function is often maladaptively upregulated to match the high energy demand required for cancer cell hyper-proliferation and invasion. Here, we report that mucolipin TRP channel 1 (TRPML1), a lysosomal Ca2+ and Zn2+ release channel that regulates multiple aspects of lysosome function, is dramatically upregulated in metastatic melanoma cells compared with normal cells. TRPML-specific synthetic agonists (ML-SAs) are sufficient to induce rapid (within hours) lysosomal Zn2+-dependent necrotic cell death in metastatic melanoma cells while completely sparing normal cells. ML-SA-caused mitochondria swelling and dysfunction lead to cellular ATP depletion. While pharmacological inhibition or genetic silencing of TRPML1 in …

Il-10 And Tgf-Β Increase Connexin-43 Expression And Membrane Potential Of Hl-1 Cardiomyocytes Coupled With Raw 264.7 Macrophages, Cora B. Cox, Mike Castro, Thomas L. Brown, Nancy J. Bigley

Neuroscience, Cell Biology & Physiology Faculty Publications

Cardiac resident macrophages facilitate electrical conduction by interacting with cardiomyocytes via connexin-43 (Cx43) hemichannels. Cx43 is critical for impulse propagation and coordination between muscle contractions. Cardiomyocyte electrophysiology can be altered when coupled with noncardiomyocyte cell types such as M2c tissue-resident macrophages. Using cocultures of murine HL-1 cardiomyocytes and RAW 264.7 macrophages, we examined the hypothesis that cytokine signals, TGF-β1 and IL-10, upregulate Cx43 expression at points of contact between the two cell types. These cytokine signals maintain the macrophages in an M2c anti-inflammatory phenotype, mimicking cardiac resident macrophages. The electrophysiology of cardiomyocytes was examined using di-8-ANEPPS potentiometric dye, which reflects …

Acute Oxygen-Sensing Via Mitochondria-Generated Temperature Transients In Rat Carotid Body Type I Cells, Ryan J. Rakoczy, Clay M. Schiebrel, Christopher N. Wyatt

Neuroscience, Cell Biology & Physiology Faculty Publications

The Carotid Bodies (CB) are peripheral chemoreceptors that detect changes in arterial oxygenation and, via afferent inputs to the brainstem, correct the pattern of breathing to restore blood gas homeostasis. Herein, preliminary evidence is presented supporting a novel oxygen-sensing hypothesis which suggests CB Type I cell “hypoxic signaling” may in part be mediated by mitochondria-generated thermal transients in TASK-channel-containing microdomains. Distances were measured between antibody-labeled mitochondria and TASK-potassium channels in primary rat CB Type I cells. Sub-micron distance measurements (TASK-1: 0.33 ± 0.04 µm, n = 47 vs TASK-3: 0.32 ± 0.03 µm, n = …

The Anti-Inflammatory Agent Bindarit Attenuates The Impairment Of Neural Development Through Suppression Of Microglial Activation In A Neonatal Hydrocephalus Mouse Model, Eri Iwasawa, Farrah N. Brown, Crystal Shula, Fatima Kahn, Sang Hoon Lee, Temugin Berta, David R. Ladle, Kenneth Campbell, Francesco T. Mangano, June Goto

Neuroscience, Cell Biology & Physiology Faculty Publications

Neonatal hydrocephalus presents with various degrees of neuroinflammation and long-term neurologic deficits in surgically treated patients, provoking a need for additional medical treatment. We previously reported elevated neuroinflammation and severe periventricular white matter damage in the progressive hydrocephalus (prh) mutant which contains a point mutation in the Ccdc39 gene, causing loss of cilia-mediated unidirectional CSF flow. In this study, we identified cortical neuropil maturation defects such as impaired excitatory synapse maturation and loss of homeostatic microglia, and swimming locomotor defects in early postnatal prh mutant mice. Strikingly, systemic application of the anti-inflammatory small molecule bindarit significantly supports healthy …

The Effect Of Cancer Cachexia Progression On The Feeding Regulation Of Skeletal Muscle Protein Turnover, Brittany R. Franch

Theses and Dissertations (ETD)

Cancer cachexia is defined as the unintentional loss of skeletal muscle mass with or without fat loss that cannot be reversed by conventional nutritional support. Cachexia occurs in ~20% of cancer patients. More specifically, 50% of lung cancer patients, the most common cancer worldwide, develop cachexia. Cachexia occurs most often in lung and gastrointestinal cancers, whereas breast and prostate have the lowest rate of cachexia. Cancer-induced cachexia disrupts skeletal muscle protein turnover (decreasing protein synthesis and increasing protein degradation). Skeletal muscle’s capacity for protein synthesis is highly sensitive to local and systemic stimuli that are controlled by mTORC1 and AMPK …

Ethanol And Opioids Do Not Act Synergistically To Depress Excitation In Carotid Body Type I Cells, Ryan J. Rakoczy, Kajal Kamra, Yoon-Jae Yi, Christopher N. Wyatt

Neuroscience, Cell Biology & Physiology Faculty Publications

The combination of opioids and ethanol can synergistically depress breathing and the acute ventilatory response to hypoxia. Multiple studies have shown that the underlying mechanisms for this may involve calcium channel inhibition in central neurons. But we have previously identified opioid receptors in the carotid bodies and shown that their activation inhibits calcium influx into the chemosensitive cells. Given that the carotid bodies contribute to the drive to breathe and underpin the acute hypoxic ventilatory response, we hypothesized that ethanol and opioids may act synergistically in these peripheral sensory organs to further inhibit calcium influx and therefore inhibit ventilation.

Methods …

Genetic Targeting Of Adult Renshaw Cells Using A Calbindin 1 Destabilized Cre Allele For Intersection With Parvalbumin Or Engrailed1, Alicia R. Lane, Indeara C. Cogdell, Thomas M. Jessell, Jay B. Bikoff, Francisco J. Alvarez

Neuroscience, Cell Biology & Physiology Faculty Publications

Renshaw cells (RCs) are one of the most studied spinal interneurons; however, their roles in motor control remain enigmatic in part due to the lack of experimental models to interfere with RC function, specifically in adults. To overcome this limitation, we leveraged the distinct temporal regulation of Calbindin (Calb1) expression in RCs to create genetic models for timed RC manipulation. We used a Calb1 allele expressing a destabilized Cre (dgCre) theoretically active only upon trimethoprim (TMP) administration. TMP timing and dose influenced RC targeting efficiency, which was highest within the first three postnatal weeks, but specificity was low with …

Nsaids Naproxen, Ibuprofen, Salicylate, And Aspirin Inhibit Trpm7 Channels By Cytosolic Acidification, Rikki Chokshi, Orville Bennett, Tetyana Zhelay, J. Ashot Kozak

Neuroscience, Cell Biology & Physiology Faculty Publications

Non-steroidal anti-inflammatory drugs (NSAIDs) are used for relieving pain and inflammation accompanying numerous disease states. The primary therapeutic mechanism of these widely used drugs is the inhibition of cyclooxygenase 1 and 2 (COX1, 2) enzymes that catalyze the conversion of arachidonic acid into prostaglandins. At higher doses, NSAIDs are used for prevention of certain types of cancer and as experimental treatments for Alzheimer’s disease. In the immune system, various NSAIDs have been reported to influence neutrophil function and lymphocyte proliferation, and affect ion channels and cellular calcium homeostasis. Transient receptor potential melastatin 7 (TRPM7) cation channels are highly expressed in …

Placenta-Specific Slc38a2/Snat2 Knockdown Causes Fetal Growth Restriction In Mice, Owen R. Vaughan, Katarzyna Maksym, Elena Silva, Kenneth Barentsen, Russel V. Anthony, Sara L. Hillman, Thomas L. Brown, Rebecca Spencer, Anna L. David, Fredrick J. Rosario, Theresa L. Powell, Thomas Jansson

Neuroscience, Cell Biology & Physiology Faculty Publications

Fetal growth restriction (FGR) is a complication of pregnancy that reduces birth weight, markedly increases infant mortality and morbidity and is associated with later-life cardiometabolic disease. No specific treatment is available for FGR. Placentas of human FGR infants have low abundance of sodium-coupled neutral amino acid transporter 2 (Slc38a2/SNAT2), which supplies the fetus with amino acids required for growth. We determined the mechanistic role of placental Slc38a2/SNAT2 deficiency in the development of restricted fetal growth, hypothesizing that placenta-specific Slc38a2 knockdown causes FGR in mice. Using lentiviral transduction of blastocysts with a small hairpin RNA (shRNA), we achieved 59% knockdown of …

Intensity-Dependent Changes In Quantified Resting Cerebral Perfusion With Multiple Sessions Of Transcranial Dc Stimulation, Matthew Sherwood, Lindsey Mcintire, Aaron T. Madaris, Kamin Kim, Charan Ranganath, R. Andy Mckinley

Neuroscience, Cell Biology & Physiology Faculty Publications

Transcranial direct current stimulation (tDCS) to the left prefrontal cortex has been shown to produce broad behavioral effects including enhanced learning and vigilance. Still, the neural mechanisms underlying such effects are not fully understood. Furthermore, the neural underpinnings of repeated stimulation remain understudied. In this work, we evaluated the effects of the repetition and intensity of tDCS on cerebral perfusion [cerebral blood flow (CBF)]. A cohort of 47 subjects was randomly assigned to one of the three groups. tDCS of 1- or 2-mA was applied to the left prefrontal cortex on three consecutive days, and resting CBF was quantified before …

Current State Of Preeclampsia Mouse Models: Approaches, Relevance, And Standardization, Christopher A. Waker, Melissa R. Kaufman, Thomas L. Brown

Neuroscience, Cell Biology & Physiology Faculty Publications

Preeclampsia (PE) is a multisystemic, pregnancy-specific disorder and a leading cause of maternal and fetal death. PE is also associated with an increased risk for chronic morbidities later in life for mother and offspring. Abnormal placentation or placental function has been well-established as central to the genesis of PE; yet much remains to be determined about the factors involved in the development of this condition. Despite decades of investigation and many clinical trials, the only definitive treatment is parturition. To better understand the condition and identify potential targets preclinically, many approaches to simulate PE in mice have been developed and …

The Role Of Action Potential Waveform In Failure Of Excitation Contraction Coupling, Xueyong Wang, Murad Nawaz, Steve R.A. Burke, Roger Bannister, Brent D. Foy, Andrew A. Voss, Mark M. Rich

Neuroscience, Cell Biology & Physiology Faculty Publications

Excitation contraction coupling (ECC) is the process by which electrical excitation of muscle is converted into force generation. Depolarization of skeletal muscle resting potential contributes to failure of ECC in diseases such as periodic paralysis, ICU acquired weakness and possibly fatigue of muscle during vigorous exercise. When extracellular K+ is raised to depolarize the resting potential, failure of ECC occurs suddenly, over a range of several mV of resting potential. While some studies have hypothesized the sudden failure of ECC is due to all-or-none failure of excitation, other studies suggest failure of excitation is graded. Intracellular recordings of action potentials …