Ulrich Hopfer

Professor

M.D., Gottingen Germany 1966
Ph.D., Johns Hopkins, 1970
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Mechanisms and Regulation of Transport in Epithelia

RESEARCH DESCRIPTION

Epithelia provide the interface between body and outside environment. This necessitates providing a general barrier and the selective, mostly active transport of specific solutes across this barrier. My efforts are directed at understanding the molecular and morphological basis of active transepithelial transport of solutes, in particular of monovalent electrolytes and nutrients. This encompasses studies of molecular mechanisms of membrane transport, energization of transport, development of epithelial cell lines, cellular regulation and integration of different signaling pathways and transporters to achieve transepithelial transport, and theoretical and mathematical modeling. Major experimental analytical tools are electrophysiology and light microscopic imaging.

Currently, major efforts are centered on sodium reabsorption in proximal tubule and collecting duct cells from the kidney. The goal of the renal studies is to understand the molecular basis for the ability of kidneys to sense the amount of body sodium and regulate excretion of sodium in the urine to maintain appropriate extracellular fluid spaces. The hypothesis is that proximal tubule cells can sense the amount of sodium by integrating information about proximal tubular fluid flow and sodium concentration and use an intrarenal, intratubular renin-angiotensin system for regulation. The studies include mathematical models of cellular mechanisms of electrolyte transport, new wild type and engineered mouse cell lines, and live cell imaging. Furthermore, the effect of fluid flow on cell morphology and function is investigated, including the possible involvement of solitary cilia on these cells in sensing fluid flow.

Importance: Research on transepithelial solute transport provides an understanding of how integrated cellular and tissue level functions are related to underlying molecules and their properties. This is important for understanding normal physiology and consequences of malfunctions, e.g., hypertension due to renal sodium retention or inflamed and congested organs due to lack of epithelial chloride secretion in cystic fibrosis.

RELATED RESEARCH AREAS

View Ulrich Hopfer's Publications on PubMed