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.

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.

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.

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.

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.

The Caterina lab is focused on dissecting mechanisms underlying acute and chronic pain sensation. We use a wide range of approaches, including mouse genetics, imaging, electrophysiology, behavior, cell culture, biochemistry and neuroanatomy to tease apart the molecular and cellular contributors to pathological pain sensation. A few of the current projects in the lab focus on defining the roles of specific subpopulations of neuronal and non-neuronal cells to pain sensation, defining the role of RNA binding proteins in the development and maintenance of neuropathic pain, and understanding how rare skin diseases known as palmoplantar keratodermas lead to severe pain in the hands and feet.

The Miho Iijima Laboratory works to make a further connection between cells' signaling events and directional movement. Our researchers have identified 17 new PH domain-containing proteins in addition to 10 previously known genes in the Dictyostelium cDNA and genome database. Five of these genes contain both the Dbl and the PH domains, suggesting these proteins are involved in actin polymerization. A PTEN homologue has also been identified in Dictyostelium that is highly conserved with the human gene. We are disrupting all of these genes and studying their roles in chemotaxis.

The nervous system has extremely complex RNA processing regulation. Dysfunction of RNA metabolism has emerged to play crucial roles in multiple neurological diseases. Mutations and pathologies of several RNA-binding proteins are found to be associated with neurodegeneration in both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). An alternative RNA-mediated toxicity arises from microsatellite repeat instability in the human genome. The expanded repeat-containing RNAs could potentially induce neuron toxicity by disrupting protein and RNA homeostasis through various mechanisms. The Sun Lab is interested in deciphering the RNA processing pathways altered by the ALS-causative mutants to uncover the mechanisms of toxicity and molecular basis of cell type-selective vulnerability. Another major focus of the group is to identify small molecule and genetic inhibitors of neuron toxic factors using various high-throughput screening platforms. Finally, we are also highly interested in developing novel CRISPR technique-based therapeutic strategies. We seek to translate the mechanistic findings at molecular level to therapeutic target development to advance treatment options against neurodegenerative diseases.

The O'Connor Lab studies the molecular basis of infectious disease using Legionella pneumophila pathogenesis as a model system. We are looking at the network of molecular interactions acting at the host-pathogen interface. Specifically, we use L. pneumophila pathogenesis to examine the numerous mechanisms by which an intracellular bacterial pathogen can establish infection, how it exploits host cell machinery to accomplish this, and how individual proteins and their component pathways coordinately contribute to disease. We are also studying the role of environmental hosts in the evolution of human pathogens. Using genetics and functional genomics, we compare and contrast the repertoires of virulence proteins required for growth in a broad assortment of hosts, how the network of molecular interactions differs between hosts, and the mechanisms by which L. pneumophila copes with this variation.

The Tom Woolf Lab studies the quarter of the genome devoted to membrane proteins. This rapidly growing branch of bioinformatics, which includes computational biophysics, represents the main research direction of our group. We aim to provide insight into critical issues for membrane systems. In pursuit of these goals, we use extensive computer calculations to build an understanding of the relations between microscopic motions and the world of experimental measurements. Our calculations use our own Beowulf computer cluster as well as national supercomputer centers. An especially strong focus has been on the computed motions of proteins and all-atom models of the lipid bilayers that mediate their influence. To compute these motions, we use the molecular dynamics program CHARMM. We hope to use our understanding of the molecular motions for the prediction of membrane protein structures using new computational methods.