Myers, Allen C., Ph.D.

The Johns Hopkins University School of Medicine
Department of Medicine
Division of Allergy & Clinical Immunology
Johns Hopkins Asthma & Allergy Center
5501 Hopkins Bayview Circle, Rm. 2A.38
Baltimore, MD 21224-6801
Tel:  410-550-2007           
Fax:  410-550-2524
Email: amyers@jhmi.edu

Research Interests

Airway nerves
Acute and chronic airway inflammation
Airway remodeling and histopathology

Biography: Dr. Myers received his Bachelor’s Degree in Biology from Towson University, Towson, MD, and his Ph.D. Degree in Pharmacology and Experimental Therapeutics from the University of Maryland School of Medicine. His postdoctoral training was with Dr. Bradley J Undem in the Division of Allergy and Clinical Immunology at the Johns Hopkins University School of Medicine. Dr. Myers has been on the faculty in the Division of Allergy and Clinical Immunology at the Johns Hopkins University School of Medicine, Department of Medicine, since 1991, Adjunct Associate Professor with the Department of Physiology, Bloomberg School of Public Health since 2003, and was an Adjunct Lecturer (Human Anatomy and Physiology), Department of Biology, University of Maryland Baltimore County,  1990-1992. Throughout his time at Hopkins, Dr. Myers has continued to produce a stream of outstanding, innovative studies all focused on airway allergic inflammation and airway innervation. He has received national and international recognition as a leading expert in autonomic regulation of the airways. Dr. Myers’ exemplary accomplishments and contributions include not only his research but also administration, teaching and training.  Furthermore, as Director of the Bayview Histology Core, he has provided an invaluable service to many researchers and collaborators at Johns Hopkins and other institutions.

Research Interest: In the lower airways, airway smooth muscle, vasculature, and glands are under constant control by the parasympathetic nervous system.  By regulating synaptic input from the brain, and controlling the activity of these tissues, parasympathetic nerves play an important role in regulating air flow to the lungs. For over 50 years, we’ve known that increased parasympathetic nerve activity contributes to reversible airway hyperactivity associated with certain pulmonary diseases such as bronchial asthma and emphysema but the cause and cellular mechanism for abnormal parasympathetic tone is still poorly understood. Other laboratories concentrate on airway smooth muscle and prejunctional release of acetylcholine with comparatively few studies focused on the parasympathetic ganglionic neurons where synaptic transmission regulates signaling from the brain. Due to the pivotal role ganglionic neurons have in regulation of air flow to the lungs, our research involves developing innovative techniques to study how parasympathetic ganglionic neurons function and are altered by airway inflammation.

Current Research:   In chronic allergy and asthma, the airways are remodeled with increased growth or number of infiltrating cells, smooth muscle, sensory nerves, and glands, all of these are potential sources of neurotrophic factors and all are in contact with parasympathetic nerves. Neurotrophic factors are growth factors that are usually associated with development of the peripheral nervous system but recently we demonstrated that adult airway neurons continue to express neurotrophin receptors and activation of these receptors can affect neuronal excitability and morphology. Our current research centers on the hypothesis that neurotrophic factors serve as important neuro-modulatory autacoids that can regulate the physiology and anatomy and, consequently, the function of adult parasympathetic neurons. For example, the neurotrophin, NGF, is increased in asthmatic airways and acutely affects synaptic transmission in airway parasympathetic ganglia: One effect is to increase the amplitude of the synaptic potential to action potential threshold, thus decreasing integration (filtering) by the neurons.  In our studies, we determine how NGF affects nicotinic receptor channels and electrophysiological properties of human and mouse ganglionic neurons in vitro.   Results from these studies will shed new light on the complex pathophysiology of airway diseases such as asthma and COPD and may ultimately determine new therapeutic treatments for these complex diseases.

Future Studies:  The subunit composition of nicotinic acetylcholine receptors of airway ganglia neurons will be studied using antibodies which recognize different alpha subunits  will be used to identify these subunits with immunohistochemistry and used to block acetylcholine-induced membrane currents. Single cell RT-PCR will be used to identify receptors subunits and  RNAi, introduced by adeno-associated virus, directed at receptor subunits are planned.  Transgenic manipulation of neurotrophins and neurotrophin receptors are also planned.

Histology and Pathology Core: Dr. Myers oversees research by, and collaborates with, many university and external scientists interested in determination and analysis of tissue inflammation and remodeling.  Using over twenty years of histology and pathology experience, this laboratory routinely uses advanced staining and histological techniques to identify changes is tissue structure evoked by environmental (allergen, ozone, pollutants) and surgical (mechanical disruption, implants, tracing dyes) interventions, as well as in genetically altered animals. Dr. Myers also established and manages a human tissue biobank, providing samples for histological, biochemical and genetic studies of human tissue.

Selected Publications:

Lieu TM, Kollarik M, Myers AC, Undem BJ. (2011) Neurotrophin- and GDNF family ligand-receptor expression in vagal sensory nerve subtypes innervating the adult guinea pig respiratory tract.  Am. J. Physiol. (Lung Cell. Mol. Physiol.) 300:L790-L798.

Pan, J, Rohde, HK, Undem, BJ,  Myers, AC.  (2010) Neurotransmitters in airway parasympathetic neurons altered by NT-3 and repeated allergen challenge. American Journal of Respiratory Cell and Molecular Biology 43(4):452-457.

Pan, J, Rohde, HK, Undem, BJ,  Myers, AC.  (2010) Neurotransmitters in airway parasympathetic neurons altered by NT-3 and repeated allergen challenge. American Journal of Respiratory Cell and Molecular Biology 43(4):452-457.

Weigand, LA,  Myers, AC.  (2010) Synaptic and membrane properties of parasympathetic ganglionic neurons innervating mouse trachea and bronchi. American Journal of Physiology (Lung Cellular and Molecular Physiology) 298(4):L593-599.

Kollarik M, Carr MJ, Ru F, Ring CJA, Hart VJ, Murdock P, Myers AC, Muroi Y, Undem BJ.

(2010) Transgene expression and effective gene silencing in vagal afferent neurons in vivo using recombinant adeno-associated virus vectors. J Physiol. 588:4303-4315.

Mazzone, S., Reynolds, S., Mori, M., Kollarik, M., Farmer, D.  Myers, AC, Canning, B.J.  (2009) Selective expression of a sodium pump isozyme by cough receptors and its essential role in regulating cough. Journal of Neuroscience, 29(43):13662-13671.

Weigand LA, Myers AC, Meeker S, Undem BJ. (2009) Mast cell-cholinergic nerve interaction in mouse airways. J Physiol. 587:3355-3362.

Duarte, AG, Terminella, L, Smith, JT, Myers, AC, Campbell, G, Lick, S. (2008)  Restoration of cough reflex in lung transplant recipients. Chest 134:310-316.

Kajekar R, and Myers AC. (2008) Calcitonin gene-related peptide affects synaptic and membrane properties of bronchial parasympathetic neurons. Journal of Respiratory Neurophysiology 160:28-36.

Hazari MS, Pan J, Myers AC.  (2007) Nerve growth factor acutely potentiates synaptic transmission in vitro and induces dendritic growth in vivo on adult neurons in airway parasympathetic ganglia.  American Journal of Physiology (Lung Cellular and Molecular Physiology)  292:L992-1001. 

Wu X, Myers AC, Goldstone AC, Togias A and  Sanico AM. (2006)  Localization of nerve growth factor and its receptors in the human nasal mucosa.  Journal of Allergy and Clinical Immunology  118:428-433.

Myers AC, Goldie R,  Hay DWP. (2005) A novel role for tachykinin neurokinin-3 receptors in regulation of human bronchial ganglia neurons. American Journal of Respiratory and Critical Care Medicine 171(3):212-216.

Laboratory

Allen C. Myers, Ph.D., Associate Professor of Medicine - senior laboratory investigator; Director, Bayview Histology Core

Holly K. Rohde, Senior Laboratory Technician

Simone Conwell.,  Research Technician

Updated 09/2011