Zinc-Secreting Paneth Cells Studied by ZP Fluorescence
Leonard J. Giblin 1, Christopher J. Chang 1, Anthony F. Bentley 1, Cathleen Frederickson 1, Stephen J. Lippard * and Christopher J. Frederickson 1*
1 NeuroBioTex, Inc., Galveston, Texas (LJG, AFB, CF, CJF); Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts (CJC, SJL)
* To whom correspondence should be addressed. E-mail: *chris{at}neurobiotex.com.
Submitted on April 25, 2005
Accepted on 20 September 2005
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Abstract |
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We have used a new family of zinc-specific-responsive fluorescent dyes (ZPs) to study the sequestration and secretion of zinc from Paneth cells, which are located in the bases of the crypts of Lieberkhn within the rat small intestine. Vivid ZP fluorescence zinc staining of Paneth cell secretory granules is seen in both cryostat sections and isolated crypts, providing firm evidence for a pool of labile (rapidly exchangeable) zinc within these cells. We further demonstrate that this ionic zinc pool is secreted under physiological conditions. In vivo stimulation of the small intestine by intraperitoneal injection of the secretagogue pilocarpine results in discrete zinc staining within the lumens of subsequently isolated crypts, concomitant with a decrease in the zinc staining of Paneth cell granules located within the same crypts. In contrast, the secretion of zinc into the lumens of isolated crypts, stimulated in vitro with either carbachol or LPS (lipopolysaccharide), is not observed. However, a distinct change in Paneth cell morphology, suggesting attempted secretion, is seen in response to the direct application of cholinergics but not LPS. These findings suggest that zinc is coreleased with other Paneth cell anti-microbials and that the intact intestine is necessary for secretion into the crypt lumen.
Key Words:
ZP1, ZP3, pilocarpine, LPS, carbachol, crypt, antimicrobial, Zinpyr, secretion
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