INTESTINAL TRANSPORT RESEARCH GROUP
Ion Transport: The broad focus of our research is gastrointestinal epithelial pathobiology. Included under this umbrella are molecular mechanisms and chemoprevention of colorectal and liver cancer, host-pathogen interactions/inflammation in the intestine, and intestinal transport in health and disease. These particular areas of focus are of monumental importance to the field of gastrointestinal health and disease. The primary symptom of enteric infection is diarrhea, it is crucial to understand the mechanisms underlying normal physiology of intestinal transport as well as pathogen-induced alterations in this process. Research on the molecular aspects of ion transport is particularly strong at UIC.
Digestive Disease Intestinal Transport Researchers Waddah Alrefai , MD: The research of Dr. Alrefai is on the biology of bile acid transport by the human intestine as well as on the role of the transporter down-regulated in adenomas (DRA) in anion exchange in the human intestine. He is interested in the regulation of the expression and activity by signaling pathways of these important intestinal transporters. Richard Benya, MD: Dr. Benya's major research focus is on the 7-transmembrane spanning, G protein-coupled (heptaspanning) receptors for gastrin-releasing peptide and for galanin. His ongoing studies for the Gastrin-releasing peptide (GRP) receptor include its role in cancers arising from the GI tract. He is also interested in the role of the galanin receptor in the secretion of chloride from intestinal epithelial cells infected with enteric bacterial pathogens.
Pradeep Dudeja, PhD: Dr. Dudeja's research focuses primarily on determining the mechanisms by which various ions, including salt, are absorbed and secreted in the human large intestine in health and disease. Using techniques developed in his laboratory, Dr. Dudeja's laboratory has identified the Na + and Cl - transport mechanisms in the luminal and basolateral membranes of the human colon. He collaborates with Dr. Hecht in studying the mechanisms by which enteric pathogens alter intestinal transport.
Gail Hecht, MD: The focus of Dr. Hecht's work is on the interactions between enteric bacterial pathogens and host intestinal epithelial cells. She is specifically interested in the related organisms enteropathogenic and enterohemorrhagic E. coli (EPEC and EHEC, respectively). The overall goal of the laboratory is to understand the mechanism by which these organisms alter the physiological functioning of the host cells including tight junction barrier function, intestinal ion transport, and stimulation of the inflammatory cascade. Both of these organisms exert their pathogenic effects by actively delivering effector molecules into host cells through a type III secretion system, which has been compared to a “molecular syringe”. Several of the projects in the laboratory revolve around identifying how specific effector molecules, EspB, D, F, and G, disrupt host cell physiology. Host cell interactors of some of these proteins have already been identified through yeast 2-hybrid analyses and more in depth studies are underway to understand how such interactions influence host cell physiology. K. Ramaswamy, PhD: The research of Dr. Ramaswamy's laboratory focuses on elucidating the mechanisms of Na + and Cl - transport in the human intestine utilizing biochemical, cellular, and molecular biological techniques. Dr. Ramaswamy studies the roles of the Na + /H + (NHE) exchanger isoforms in Na + transport, and Cl - /HCO 3 - exchanger (AE) isoforms in the transport of Cl - and other anions, in the human small intestine and colon. Current studies include determining the transcriptional and post-translational regulation of the human NHE-2 and NHE-3 isoforms, cloning the transporter for short-chain fatty acids, and characterizing various human colon ion transport mechanisms.
Mrinalini Rao, PhD: Dr. Rao's research is directed to understanding the molecular and cellular mechanism(s) underlying hormonal and neurotransmitter regulation of physiological processes relating to epithelial ion transport. Ion transport processes in epithelia, such as those lining the gastrointestinal tract, are involved both in the vectorial movement of salt and water, as well as in general "housekeeping" functions such as regulation of volume, pH and growth. Dr. Rao's laboratory focuses on examining the role of post-translational modifications, such as protein phosphorylation and dephosphorylation, which are involved in the multiple aspects of hormone-mediated ion transport. Additional UIC Researchers
Karen Colley, PhD: The overall goal of Dr. Colley's research program is to understand how the process of glycoprotein glycosylation is controlled and how attached oligosaccharide structures influence the biological function of the proteins that they modify. As carbohydrate structures are now appreciated to play important roles in mediating and modulating cell interactions during development, disease and in the normal cell, these questions have taken on increased importance. Her laboratory studies a family of glycosyltransferases called the sialyltransferases that add terminal sialic acid to glycoproteins and glycolipids.
Jack Kaplan, PhD, FRS: Dr. Kaplan's lab focuses on the P-type ATPase structure-function assembly and trafficking. The active transport of ions across cell membranes is performed by P-type ATPases. These are integral membrane proteins which use the energy of hydrolysis of ATP to pump ions across biological membranes. The mechanism by which these proteins couple ATP hydrolysis to ion transport is one of the central interests of the laboratory. These proteins form phosphorylated intermediates with ATP and transport Na+, K+, H+, Ca2+, Cu2+, Cd2+ etc. across animal, bacterial, and plant cell membranes.
Theodore Mazzone, MD: Dr. Mazzone's research focuses on cholesterol metabolism and phospholipid and sterol homeostasis. He is actively collaborating with Dr. Scott Cotler on the dynamics of lipid metabolism in patients with non-alcoholic steatohepatitis.
Randal Skidgel, PhD: This laboratory focuses on peptidases, enzymes that control the level and activity of peptide hormones. Peptidases control many biological processes including normal and malignant cell growth, blood pressure, pain and analgesia, immune functions, etc. The peptidases emphasized in their studies are carboxypeptidases - enzymes that cleave one amino acid at time from the C-terminus of a peptide. Removal of a C-terminal amino acid can terminate the action of a peptide or alter its receptor specificity because many peptides bind to receptors through this part of the molecule. The approaches used to study the peptidases are multifaceted and include biochemical studies of enzyme properties, cloning, sequencing and expression of recombinant enzymes and studies of the distribution and function of the peptidases in tissues, clinical samples and cultured cells.
Papasani Subbaiah, PhD: The focus of Dr. Subbaiah's laboratory is the mechanisms involved in the novel functions of sphingomyelin in the inhibition of LCAT, lipase, phospholipase and CETP reactions, and in the modulation of lipid peroxidation. The physiological relevance of these phenomena are being explored.
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