Department of Medicine

Faculty

Shen-Ling Xia, Ph.D.

Dr. Xia received his B.S. degree in Computer Sciences in 1983 from Shanghai Jiao Tong University E&M Branch in China. He received his M.S. degree in Biomedical Engineering in 1988 from University of Southern California and his Ph.D. degree in Physiology in 1995 from University of Toronto.  Then he went to Dr. Gordon Fain's laboratory for his postdoctoral training at University of California at Los Angeles.  In 1997 Dr. Xia joined the faculty in the Department of Medicine at the University of Florida. Dr. Xia is currently the Director of the Laser Scanning Confocal Microscopy Core Laboratory at the North Florida/South Georgia Veterans Health System (NF/SGVHS).  He also holds a joint appointment in the Department of Physiology and Functional Genomics.

Publications

Research Interest

The long-term research goal of our laboratory is to determine the physiological effect of purinergic signaling in sodium homeostasis, a major determinant of blood pressure.  Purinergic signaling comprises the binding of extracellular ATP to two distinctive classes of receptor: G-protein coupled P2Y receptor, and ligand-gated ion channel P2X receptor. In the kidney, renal cells release ATP in physiological circumstances and in tissue ischemia or cell injury. Extracellular ATP and other nucleotides are now considered to be autocrine (self-regulatory) and paracrine (proximate-regulatory) agents of various physiological and pathophysiological processes.  Purinergic signaling has been suggested to play an important role in stimulating renal cell growth and division, developing polycystic kidney disease, controlling microvascular function, and in regulating epithelial ion transport.

In using renal collecting duct epithelial cells, we have demonstrated for the first time that serum and glucocorticoid inducible kinase-1 (Sgk1) can be downregulated by nucleotides via the activation of P2 receptors. Sgk1 was known to stimulate epithelial sodium channel (ENaC) activity in renal collecting duct cells and it can be upregulated by mineralocorticoids. Our recent studies also show that aldosterone up-regulated Sgk1 can be suppressed by ATP agonists via activation of P2 receptors. These data strongly suggest that renal purinergic signaling has the potential to influence ion transport in the kidney. Our preliminary studies indicate that most of the P2X receptor subtypes, if not all known subtypes, express in the native cortex, outer medulla, and inner medulla of the rat and mouse kidneys. We are currently examining the function of these receptors under different physiological conditions and identifying their specific roles in ENaC expression and function.

The techniques that have been used in the laboratory include patch clamp recordings of single channel and whole cell current, short circuit current measurement, one-photon and two photon confocal imaging microscopy for cells and tissues, ratiometric imaging microscopy with fluorescence probes for intracellular Ca, Na and pH, Western blotting, ELISA, qRT-PCR, siRNA, immunohistochemistry, supplemented by animal dietary regulation, microdisection of native tissues, laser capture and microinjection of living cells, primary culture and cell line culture.