Medical Physiology Commons^™

Exposure To Phthalates Affects Calcium Handling And Intercellular Connectivity Of Human Stem Cell-Derived Cardiomyocytes, Nikki G. Posnack, Rabia Idrees, Hao Ding, Rafael Jaimes Iii, Gulnaz Stybayeva, Zaruhi Karabekian, Michael A. Laflamme, Narine Sarvazyan

Pharmacology and Physiology Faculty Publications

Background

The pervasive nature of plastics has raised concerns about the impact of continuous exposure to plastic additives on human health. Of particular concern is the use of phthalates in the production of flexible polyvinyl chloride (PVC) products. Di-2-ethylhexyl-phthalate (DEHP) is a commonly used phthalate ester plasticizer that imparts flexibility and elasticity to PVC products. Recent epidemiological studies have reported correlations between urinary phthalate concentrations and cardiovascular disease, including an increased risk of high blood pressure and coronary risk. Yet, there is little direct evidence linking phthalate exposure to adverse effects in human cells, including cardiomyocytes.

Methods and Results

The …

Guidelines For Pre-Clinical Assessment Of The Acetylcholine Receptor-Specific Passive Transfer Myasthenia Gravis Model - Recommendations For Methods And Experimental Designs., Linda L. Kusner, Mario Losen, Angela Vincent, Jon Lindstrom, Socrates Tzartos, Konstantinos Lazaridis, Pilar Martinez-Martinez

Pharmacology and Physiology Faculty Publications

Antibodies against the muscle acetylcholine receptor (AChR) are the most common cause of myasthenia gravis (MG). Passive transfer of AChR antibodies from MG patients into animals reproduces key features of human disease, including antigenic modulation of the AChR, complement-mediated damage of the neuromuscular junction, and muscle weakness. Similarly, AChR antibodies generated by active immunization in experimental autoimmune MG models can subsequently be passively transferred to other animals and induce weakness. The passive transfer model is useful to test therapeutic strategies aimed at the effector mechanism of the autoantibodies. Here we summarize published and unpublished experience using the AChR passive transfer …

Voltage-Gated Na+ Channel Activity Increases Colon Cancer Transcriptional Activity And Invasion Via Persistent Mapk Signaling, Carrie D. House, Bi-Dar Wang, Kristin Ceniccola, Russell Williams, May Simaan, Norman H. Lee, +7 Additional Authors

Pharmacology and Physiology Faculty Publications

Functional expression of voltage-gated Na⁺ channels (VGSCs) has been demonstrated in multiple cancer cell types where channel activity induces invasive activity. The signaling mechanisms by which VGSCs promote oncogenesis remain poorly understood. We explored the signal transduction process critical to VGSC-mediated invasion on the basis of reports linking channel activity to gene expression changes in excitable cells. Coincidentally, many genes transcriptionally regulated by the SCN5A isoform in colon cancer have an over-representation of cis-acting sites for transcription factors phosphorylated by ERK1/2 MAPK. We hypothesized that VGSC activity promotes MAPK activation to induce transcriptional changes in invasion-related genes. Using …

Analysis For Co-Occurring Sequence Features Identifies Link Between Common Synonymous Variant And An Early-Terminated Npc1 Isoform, Mercedeh Movassagh, Prakriti Mudvari, Maria Kokkinaki, Nathan J. Edwards, Nady Golestaneh, Anelia Horvath

Pharmacology and Physiology Faculty Publications

Direct assessment of allelic phase for DNA and RNA features of diploid genomes has been challenging for Sanger sequencing, due to its allele-conflating base-calling signal. Massively parallel sequencing technologies are based on the generation of a continuous copy of a single strand sequence segments, thus preserving the allelic relation between the features of the original molecules. We have performed a transcriptome-wide search for co-occurrence of variant nucleotides and exon-intron boundaries positioned within the length of a single sequencing read. Analysis of 75 human transcriptomes from retinal pigment epithelia (RPE), glioblastoma, low-grade brain tumor, breast cancer and colon cancer, have identified …

Visualization Of Oxytocin Release That Mediates Paired Pulse Facilitation In Hypothalamic Pathways To Brainstem Autonomic Neurons, Ramon A. Pinol, Heather Jameson, Anastas Popratiloff, Norman H. Lee, David Mendelowitz

Pharmacology and Physiology Faculty Publications

Recent work has shown that oxytocin is involved in more than lactation and uterine contraction. The paraventricular nucleus of the hypothalamus (PVN) contains neuroendocrine neurons that control the release of hormones, including vasopressin and oxytocin. Other populations of PVN neurons do not release hormones, but rather project to and release neurotransmitters onto other neurons in the CNS involved in fluid retention, thermoregulation, sexual behavior and responses to stress. Activation of oxytocin receptors can be cardioprotective and reduces the adverse cardiovascular consequences of anxiety and stress, yet how oxytocin can affect heart rate and cardiac function is unknown. While anatomical work …

Cc2d1a Regulates Human Intellectual And Social Function As Well As Nf-Κb Signaling Homeostasis., M. Chiara Manzini, Lan Xiong, Ranad Shaheen, Dimira E Tambunan, Stefania Di Costanzo, Vanessa Mitisalis, +15 Additional Authors

Pharmacology and Physiology Faculty Publications

Autism spectrum disorder (ASD) and intellectual disability (ID) are often comorbid, but the extent to which they share common genetic causes remains controversial. Here, we present two autosomal-recessive "founder" mutations in the CC2D1A gene causing fully penetrant cognitive phenotypes, including mild-to-severe ID, ASD, as well as seizures, suggesting shared developmental mechanisms. CC2D1A regulates multiple intracellular signaling pathways, and we found its strongest effect to be on the transcription factor nuclear factor κB (NF-κB). Cc2d1a gain and loss of function both increase activation of NF-κB, revealing a critical role of Cc2d1a in homeostatic control of intracellular signaling. Cc2d1a knockdown in neurons …

Survivin As Potential Mediator To Support Autoreactive Cell Survival In Myasthenia Gravis: A Human And Animal Model Study, Linda Louise Kusner, Michael J. Ciesielski, Alexander Marx, Henry J. Kaminski, Robert A. Fenstermaker

Pharmacology and Physiology Faculty Publications

The mechanisms that underlie the development and maintenance of autoimmunity in myasthenia gravis are poorly understood. In this investigation, we evaluate the role of survivin, a member of the inhibitor of apoptosis protein family, in humans and in two animal models. We identified survivin expression in cells with B lymphocyte and plasma cells markers, and in the thymuses of patients with myasthenia gravis. A portion of survivin-expressing cells specifically bound a peptide derived from the alpha subunit of acetylcholine receptor indicating that they recognize the peptide. Thymuses of patients with myasthenia gravis had large numbers of survivin-positive cells with fewer …

Kinase Insert Domain Receptor/Vascular Endothelial Growth Factor Receptor 2 (Kdr) Genetic Variation Is Associated With Ovarian Hyperstimulation Syndrome, Travis J. O'Brien, Arthur F. Harralson, Tuyen Tran, Ian Gindoff, Funda E. Orkunoglu-Suer, David Frankfurter, Paul Gindoff

Pharmacology and Physiology Faculty Publications

Background

The objective of this investigation was to determine if kinase insert domain/vascular endothelial growth factor receptor 2 (KDR/VEGFR2) genetic variation was associated with the development of ovarian hyperstimulation syndrome (OHSS) in patients undergoing controlled ovarian hyperstimulation (COH).

Methods

This was a case-control study of 174 patients who underwent controlled ovarian stimulation. Patient blood samples were genotyped for single nucleotide polymorphisms (SNPs) spanning the KDR locus. OHSS development, clinical outcome variables, SNP and haplotype frequencies were compared between control (n = 155) and OHSS (n = 19) groups.

Results

Patients who developed OHSS had significantly higher response markers (estradiol levels …

Targeting Therapy To The Neuromuscular Junction: Proof Of Concept, Linda L. Kusner, Namita Satija, Georgiana Cheng, Henry J. Kaminski

Pharmacology and Physiology Faculty Publications

Introduction: The site of pathology in myasthenia gravis (MG) is the neuromuscular junction (NMJ). Our goal was to determine the ability to direct complement inhibition to the NMJ.

Methods: A single-chain antibody directed against the alpha subunit of the acetylcholine receptor was synthesized (scFv-35) and coupled to decay-accelerating factor (DAF, scFv-35-DAF). scFv-35-DAF was tested in a passive model of experimentally acquired MG.

Results: Administration of scFv-35-DAF to mice deficient in intrinsic complement inhibitors produced no weakness despite confirmation of its localization to the NMJ and no evidence of tissue destruction related to complement activation. Rats with experimentally …

Evidence That Bdnf Regulates Heart Rate By A Mechanism Involving Increased Brainstem Parasympathetic Neuron Excitability, Ruqian Wan, Letitia A. Weigand, Ryan Bateman, Kathleen Griffioen, David Mendelowitz, Mark P. Mattson

Pharmacology and Physiology Faculty Publications

Autonomic control of heart rate is mediated by cardioinhibitory parasympathetic cholinergic neurons located in the brainstem and stimulatory sympathetic noradrenergic neurons. During embryonic development the survival and cholinergic phenotype of brainstem autonomic neurons is promoted by brain-derived neurotrophic factor (BDNF). We now provide evidence that BDNF regulates heart rate by a mechanism involving increased brainstem cardioinhibitory parasympathetic activity. Mice with a BDNF haploinsufficiency exhibit elevated resting heart rate, and infusion of BDNF intracerebroventricularly reduces heart rate in both wild-type and BDNF+/− mice. The atropine-induced elevation of heart rate is diminished in BDNF+/− mice and is restored by BDNF infusion, whereas …

Bisphenol A Exposure And Cardiac Electrical Conduction In Excised Rat Hearts, Nikki G. Posnack, Rafael Jaimes Iii, Huda Asfour, Luther Swift, Anastasia M. Wengrowski, Narine Sarvazyan, Matthew Kay

Pharmacology and Physiology Faculty Publications

BACKGROUND:

Bisphenol A (BPA) is used to produce polycarbonate plastics and epoxy resins that are widely used in everyday products, such as food and beverage containers, toys and medical devices. Human biomonitoring studies have suggested that a large proportion of the population may be exposed to BPA. Recent epidemiological studies have reported correlations between increased BPA urinary concentrations and cardiovascular disease; yet the direct effects of BPA on the heart are unknown.

OBJECTIVES:

The goal of our studies was to measure BPA's effect (0.1-100 μM) on cardiac impulse propagation ex vivo, using excised whole hearts from adult rats.

METHODS: …

Concordant Integrative Gene Set Enrichment Analysis Of Multiple Large-Scale Two-Sample Expression Data Sets, Yinglei Lai, Fanni Zhang, Tapan K. Nayak, Reza Modarres, Norman H. Lee, Timothy A. Mccaffrey

Pharmacology and Physiology Faculty Publications

Background

Gene set enrichment analysis (GSEA) is an important approach to the analysis of coordinate expression changes at a pathway level. Although many statistical and computational methods have been proposed for GSEA, the issue of a concordant integrative GSEA of multiple expression data sets has not been well addressed. Among different related data sets collected for the same or similar study purposes, it is important to identify pathways or gene sets with concordant enrichment.

Methods

We categorize the underlying true states of differential expression into three representative categories: no change, positive change and negative change. Due to data noise, what …

Heat Shock Factor 2 Is A Stress‐Responsive Mediator Of Neuronal Migration Defects In Models Of Fetal Alcohol Syndrome, Rachid El Fatimy, Federico Miozzo, Anne Le Mouël, Ryma Abane, Leslie Schwendimann, Délara Sabéran‐Djoneidi, Aurélie De Thonel, Illiasse Massaoudi, Liliana Paslaru, Kazue Hashimoto-Torii, Elisabeth Christians, Pasko Rakic, Pierre Gressens, Valérie Mezger

Pharmacology and Physiology Faculty Publications

Fetal alcohol spectrum disorder (FASD) is a frequent cause of mental retardation. However, the molecular mechanisms underlying brain development defects induced by maternal alcohol consumption during pregnancy are unclear. We used normal andHsf2‐deficient mice and cell systems to uncover a pivotal role for heat shock factor 2 (HSF2) in radial neuronal migration defects in the cortex, a hallmark of fetal alcohol exposure. Upon fetal alcohol exposure, HSF2 is essential for the triggering of HSF1 activation, which is accompanied by distinctive post‐translational modifications, and HSF2 steers the formation of atypical alcohol‐specific HSF1–HSF2 heterocomplexes. This perturbs the in vivo binding …

A Mechanism Linking Id2-Tgfβ Crosstalk To Reversible Adaptive Plasticity In Neuroblastoma, Lina Chakrabarti, Bi-Dar Wang, Norman H. Lee, Anthony D. Sandler

Pharmacology and Physiology Faculty Publications

The ability of high-risk neuroblastoma to survive unfavorable growth conditions and multimodal therapy has produced an elusive childhood cancer with remarkably poor prognosis. A novel phenomenon enabling neuroblastoma to survive selection pressure is its capacity for reversible adaptive plasticity. This plasticity allows cells to transition between highly proliferative anchorage dependent (AD) and slow growing, anoikis-resistant anchorage independent (AI) phenotypes. Both phenotypes are present in established mouse and human tumors. The differential gene expression profile of the two cellular phenotypes in the mouse Neuro2a cell line delineated pathways of proliferation in AD cells or tyrosine kinase activation/ apoptosis inhibition in AI …

Auditory Stimuli Mimicking Ambient Sounds Drive Temporal "Delta Brushes" In Premature Infants, Mathilde Chipaux, Matthew Colonnese, Audrey Mauguen, Laure Fellous, Mostafa Mokhtari, Oscar Lezcano, Mathieu Milh, Olivier Dulac, Catherine Chiron, Rustem Khazipov, Anna Kaminska

Pharmacology and Physiology Faculty Publications

In the premature infant, somatosensory and visual stimuli trigger an immature electroencephalographic (EEG) pattern, “delta-brushes,” in the corresponding sensory cortical areas. Whether auditory stimuli evoke delta-brushes in the premature auditory cortex has not been reported. Here, responses to auditory stimuli were studied in 46 premature infants without neurologic risk aged 31 to 38 postmenstrual weeks (PMW) during routine EEG recording. Stimuli consisted of either low-volume technogenic “clicks” near the background noise level of the neonatal care unit, or a human voice at conversational sound level. Stimuli were administrated pseudo-randomly during quiet and active sleep. In another protocol, the cortical response …

The Minimum M3-M4 Loop Length Of Neurotransmitter-Activated Pentameric Receptors Is Critical For The Structural Integrity Of Cytoplasmic Portals, Daniel T. Baptista-Hon, Tarek Z. Deeb, Jeremy J. Lambert, John A. Peters, Tim G. Hales

Pharmacology and Physiology Faculty Publications

The 5-HT₃A receptor homology model, based on the partial structure of the nicotinic acetylcholine receptor from Torpedo marmorata, reveals an asymmetric ion channel with five portals framed by adjacent helical amphipathic (HA) stretches within the 114-residue loop between the M3 and M4 membrane-spanning domains. The positive charge of Arg-436, located within the HA stretch, is a rate-limiting determinant of single channel conductance (γ). Further analysis reveals that positive charge and volume of residue 436 are determinants of 5-HT₃A receptor inward rectification, exposing an additional role for portals. A structurally unresolved stretch of 85 residues constitutes …

Vbp15, A Glucocorticoid Analogue, Is Effective At Reducing Allergic Lung Inflammation In Mice, Jesse M. Damsker, Blythe C. Dillingham, Mary C. Rose, Molly A. Balsley, Christopher R. Heier, Alan M. Watson, Erik J. Stemmy, Rosalyn A. Jurjus, Tony Huynh, Kathleen Tatem, Kitipong Uaesoontrachoon, Dana M. Berry, Angela S. Benton, Robert J. Freishtat, Eric P. Hoffman, John M. Mccall, Heather Gordish-Dressman, Stephanie L. Constant, Erica K.M. Reeves, Kanneboyina Nagaraju

Pharmacology and Physiology Faculty Publications

Asthma is a chronic inflammatory condition of the lower respiratory tract associated with airway hyperreactivity and mucus obstruction in which a majority of cases are due to an allergic response to environmental allergens. Glucocorticoids such as prednisone have been standard treatment for many inflammatory diseases for the past 60 years. However, despite their effectiveness, long-term treatment is often limited by adverse side effects believed to be caused by glucocorticoid receptor-mediated gene transcription. This has led to the pursuit of compounds that retain the anti-inflammatory properties yet lack the adverse side effects associated with traditional glucocorticoids. We have developed a novel …

Association Between The Luteinizing Hormone/Chorionic Gonadotropin Receptor (Lhcgr) Rs4073366 Polymorphism And Ovarian Hyperstimulation Syndrome During Controlled Ovarian Hyperstimulation, Travis J. O'Brien, Mariah M. Kalmin, Arthur F. Harralson, Adam M. Clark, Ian Gindoff, Samuel J. Simmens, David Frankfurter, Paul Gindoff

Pharmacology and Physiology Faculty Publications

Background

The aim of this study was to determine the relationship between a purported luteinizing hormone/chorionic gonadotropin (LHCGR) high function polymorphism (rs4539842/insLQ) and outcome to controlled ovarian hyperstimulation (COH).

Methods

This was a prospective study of 172 patients undergoing COH at the Fertility and IVF Center at GWU. DNA was isolated from blood samples and a region encompassing the insLQ polymorphism was sequenced. We also investigated a polymorphism (rs4073366 G > C) that was 142 bp frominsLQ. The association of the insLQ and rs4073366 alleles and outcome to COH (number of mature follicles, …

Androgen Receptor-Target Genes In African American Prostate Cancer Disparities, Bi-Dar Wang, Qi Yang, Kristin Ceniccola, Fernando Bianco, Ramez Andrawis, Thomas W. Jarrett, Harold A. Frazier, Steven R. Patierno, Norman H. Lee

Pharmacology and Physiology Faculty Publications

The incidence and mortality rates of prostate cancer (PCa) are higher in African American (AA) compared to Caucasian American (CA) men. To elucidate the molecular mechanisms underlying PCa disparities, we employed an integrative approach combining gene expression profiling and pathway and promoter analyses to investigate differential transcriptomes and deregulated signaling pathways in AA versus CA cancers. A comparison of AA and CA PCa specimens identified 1,188 differentially expressed genes. Interestingly, these transcriptional differences were overrepresented in signaling pathways that converged on the androgen receptor (AR), suggesting that the AR may be a unifying oncogenic theme in AA PCa. Gene promoter …

Phthalate Exposure Changes The Metabolic Profile Of Cardiac Muscle Cells, Nikki G. Posnack, Luther M. Swift, Matthew W. Kay, Norman H. Lee, Narine Sarvazyan

Pharmacology and Physiology Faculty Publications

Background: Phthalates are common plasticizers present in medical-grade plastics and other everyday products. They can also act as endocrine-disrupting chemicals and have been linked to the rise in metabolic disorders. However, the effect of phthalates on cardiac metabolism remains largely unknown.

Objectives: We examined the effect of di(2-ethylhexyl)phthalate (DEHP) on the metabolic profile of cardiomyocytes because alterations in metabolic processes can lead to cell dysfunction.

Methods: Neonatal rat cardiomyocytes were treated with DEHP at a concentration and duration comparable to clinical exposure (50–100 μg/mL, 72 hr). We assessed the effect of DEHP on gene expression using microarray analysis. Physiological responses …

Synaptic And Intrinsic Activation Of Gabaergic Neurons In The Cardiorespiratory Brainstem Network, Julie G. Frank, David Mendelowitz

Pharmacology and Physiology Faculty Publications

GABAergic pathways in the brainstem play an essential role in respiratory rhythmogenesis and interactions between the respiratory and cardiovascular neuronal control networks. However, little is known about the identity and function of these GABAergic inhibitory neurons and what determines their activity. In this study we have identified a population of GABAergic neurons in the ventrolateral medulla that receive increased excitatory post-synaptic potentials during inspiration, but also have spontaneous firing in the absence of synaptic input. Using transgenic mice that express GFP under the control of the Gad1 (GAD67) gene promoter, we determined that this population of GABAergic neurons is in …

Y Chromosome Lineages In Men Of West African Descent, Jada Benn Torres, Menahem B. Doura, Shomarka O.Y. Keita, Rick A. Kittles

Pharmacology and Physiology Faculty Publications

The early African experience in the Americas is marked by the transatlantic slave trade from ~1619 to 1850 and the rise of the plantation system. The origins of enslaved Africans were largely dependent on European preferences as well as the availability of potential laborers within Africa. Rice production was a key industry of many colonial South Carolina low country plantations. Accordingly, rice plantations owners within South Carolina often requested enslaved Africans from the so-called “Grain Coast” of western Africa (Senegal to Sierra Leone). Studies on the African origins of the enslaved within other regions of the Americas have been limited. …

Vascular Inflammatory Cells In Hypertension., David G Harrison, Paul J. Marvar, Jens M Titze

Pharmacology and Physiology Faculty Publications

Hypertension is a common disorder with uncertain etiology. In the last several years, it has become evident that components of both the innate and adaptive immune system play an essential role in hypertension. Macrophages and T cells accumulate in the perivascular fat, the heart and the kidney of hypertensive patients, and in animals with experimental hypertension. Various immunosuppressive agents lower blood pressure and prevent end-organ damage. Mice lacking lymphocytes are protected against hypertension, and adoptive transfer of T cells, but not B cells in the animals restores their blood pressure response to stimuli such as angiotensin II or high salt. …