Research Lab Results
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Katherine Wilson Lab
Research in the Wilson Lab focuses on three components of nuclear lamina structure: lamins, LEM-domain proteins (emerin), and BAF. These three proteins all bind each other directly, and are collectively required to organize and regulate chromatin, efficiently segregate chromosomes and rebuild nuclear structure after mitosis. Mutations in one or more of these proteins cause a variety of diseases including Emery-Dreifuss muscular dystrophy (EDMD), cardiomyopathy, lipodystrophy and diabetes, and accelerated aging. We are examining emerin's role in mechanotransduction, how emerin and lamin A are regulated, and whether misregulation contributes to disease. -
Landon King Lab
The Landon King Lab studies aquaporins water-specific membrane channel proteins. We hope to understand how these proteins contribute to water homeostasis in the respiratory tract and how their expression or function may be altered in disease states. -
Zhaozhu Qiu Laboratory
Ion channels are pore-forming membrane proteins gating the flow of ions across the cell membrane. Among their many functions, ion channels regulate cell volume, control epithelial fluid secretion, and generate the electrical impulses in our brain. The Qiu Lab employs a multi-disciplinary approach including high-throughput functional genomics, electrophysiology, biochemistry, and mouse genetics to discover novel ion channels and to elucidate their role in health and disease. -
O'Rourke Lab
The O’Rourke Lab uses an integrated approach to study the biophysics and physiology of cardiac cells in normal and diseased states. Research in our lab has incorporated mitochondrial energetics, Ca2+ dynamics, and electrophysiology to provide tools for studying how defective function of one component of the cell can lead to catastrophic effects on whole cell and whole organ function. By understanding the links between Ca2+, electrical excitability and energy production, we hope to understand the cellular basis of cardiac arrhythmias, ischemia-reperfusion injury, and sudden death. We use state-of-the-art techniques, including single-channel and whole-cell patch clamp, microfluorimetry, conventional and two-photon fluorescence imaging, and molecular biology to study the structure and function of single proteins to the intact muscle. Experimental results are compared with simulations of computational models in order to understand the findings in the context of the system as a whole. Ongoing studies in our lab are focused on identifying the specific molecular targets modified by oxidative or ischemic stress and how they affect mitochondrial and whole heart function. The motivation for all of the work is to understand • how the molecular details of the heart cell work together to maintain function and • how the synchronization of the parts can go wrong Rational strategies can then be devised to correct dysfunction during the progression of disease through a comprehensive understanding of basic mechanisms. Brian O’Rourke, PhD, is a professor in the Division of Cardiology and Vice Chair of Basic and Translational Research, Department of Medicine, at the Johns Hopkins University. -
Foster Lab
The Foster Lab uses the tools of protein biochemistry and proteomics to tackle fundamental problems in the fields of cardiac preconditioning and heart failure. Protein networks are perturbed in heart disease in a manner that correlates only weakly with changes in mRNA transcripts. Moreover, proteomic techniques afford the systematic assessment of post-translational modifications that regulate the activity of proteins responsible for every aspect of heart function from electrical excitation to contraction and metabolism. Understanding the status of protein networks in the diseased state is, therefore, key to discovering new therapies. D. Brian Foster, Ph.D., is an assistant professor of medicine in the division of cardiology, and serves as Director of the Laboratory of Cardiovascular Biochemistry at the Johns Hopkins University School of Medicine. -
Intestinal Chloride Secretion
Intestinal chloride secretion is stimulated during diarrhea. Cholera toxin is secreted by bacterium Vibrio cholera and is responsible for the watery diarrhea after cholera infection. Mechanistically, cholera toxin increases intracellular cyclic AMP, which subsequently activates protein kinase A and the cystic fibrosis transmembrane regulator chloride channel (CFTR). However, we recently identified an intestinal cAMP-Ca cross-talk signaling pathway that is initiated by elevation of intracellular cAMP and subsequently elevates intracellular Ca concentrations through the exchange protein activated by cAMP (Epac). This observation suggests that both CFTR and calcium-activated chloride channels are targets of elevated intracellular cAMP signaling molecule. Therefore, we are studying the role of calcium-activated Cl channels in intestinal chloride secretion under physiological conditions and during diarrhea. We are also determining whether the recently identified transmembrane protein 16 family of proteins, which are calcium-activated chloride channels, is also involved in intestinal chloride secretion in addition to the well characterized CFTR channel. Increased understanding of regulation of intestinal Cl secretion provides the necessary background information for the development of therapeutic drugs for the treatment of diarrhea, constipation and cystic fibrosis. The discovery that calcium-activated chloride channels are involved in intestinal chloride secretion provides additional targets for anti-diarrhea drug development. -
Intestinal Na/H Exchangers
Secretory diarrhea is a leading cause of childhood morbidity and mortality in developing countries. While diarrhea can be treated with oral rehydration solution (ORS), inclusion of zinc with oral ORS has been shown to reduce the duration of diarrhea. However, how zinc improves diarrhea is not known. It has been shown that zinc acts as an intestinal epithelial cell basolateral potassium channel blocker of cyclic AMP-mediated chloride secretion. We discovered that zinc also stimulates intestinal sodium and water absorption via the epithelial Na/H exchanger, NHE3. Zinc reverses the effect of cyclic AMP inhibition of NHE3 activity. The effect of zinc on NHE3 cannot be duplicated with other divalent metal ions. It has been well established that Na/H exchanger regulatory proteins are involved in NHE3 regulation. Whether these regulatory proteins are involved in zinc stimulation of NHE3 is a focus of our study. Our goal is to reveal mechanisms to explain how zinc improves diarrhea and to understand the role of zinc in salt and water homeostasis in the gut. Our study will provide a scientific basis to justify the inclusion of zinc in ORS for the treatment of secretory diarrhea. -
Haughey Lab: Neurodegenerative and Neuroinfectious Disease
Dr. Haughey directs a disease-oriented research program that address questions in basic neurobiology, and clinical neurology. The primary research interests of the laboratory are: 1. To identify biomarkers markers for neurodegenerative diseases including HIV-Associated Neurocognitive Disorders, Multiple Sclerosis, and Alzheimer’s disease. In these studies, blood and cerebral spinal fluid samples obtained from ongoing clinical studies are analyzed for metabolic profiles through a variety of biochemical, mass spectrometry and bioinformatic techniques. These biomarkers can then be used in the diagnosis of disease, as prognostic indicators to predict disease trajectory, or as surrogate markers to track the effectiveness of disease modifying interventions. 2. To better understand how the lipid components of neuronal, and glial membranes interact with proteins to regulate signal transduction associated with differentiation, motility, inflammatory signaling, survival, and neuronal excitability. 3. To understand how extracellular vesicles (exosomes) released from brain resident cells regulate neuronal excitability, neural network activity, and peripheral immune responses to central nervous system damage and infections. 4. To develop small molecule therapeutics that regulate lipid metabolism as a neuroprotective and restorative strategy for neurodegenerative conditions. -
Heng Zhu Lab
The Zhu lab is focused on characterizing the activities of large collection of proteins, building signaling networks for better understanding the mechanisms of biological processes, and identifying biomarkers in human diseases and cancers. More specifically, our group is interested in analyzing protein posttranslational modifications, and identifying important components involved in transcription networks and host-pathogen interactions on the proteomics level, and biomarkers in human IBD diseases. -
Mass Spectrometry Core
The Mass Spectrometry Core identifies and quantifies proteins that change expression in well-characterized protein fractions from cancerous cells or tissues. This includes identifying and quantifying changes in binding partners and post-translational modifications. Column chromatography and gel electrophoresis-based one and two-dimensional separations of protein complexes coupled to mass spectrometry are used. Techniques such as difference gel electrophoresis (DIGE), isobaric tag for relative and absolute quantitation (iTRAQ) and 18O-labeling as well as non-labeling methods (MudPit, multi-dimensional protein identification technology) are available for quantifying relative differences in protein expression and post-translational modifications. We developed methods to detect post-translational modifications such as LCMS methods to accurately determine the intact mass of proteins, selective fluorescent labeling of S-nitrosothiols (S-FLOS) to detect nitrosated cysteines in proteins, and ion mapping methods to map post-translational modifications that produce a signature mass or mass difference when the modified peptide is fragmented.