Modulation of Mouse Paneth Cell α-Defensin Secretion by mIKCa1, a Ca2+-activated, Intermediate Conductance Potassium Channel

Paneth cells in small intestinal crypts secrete microbicidal α-defensins in response to bacteria and bacterial antigens (Ayabe, T., Satchell, D. P., Wilson, C. L., Parks, W. C., Selsted, M. E., and Ouellette, A. J. (2000)Nat. Immunol. 1, 113–138). We now report that the Ca2+-activated K+ channel mIK...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 2002-02, Vol.277 (5), p.3793-3800
Main Authors: Ayabe, Tokiyoshi, Wulff, Heike, Darmoul, Dalila, Cahalan, Michael D., Chandy, K. George, Ouellette, Andre J.
Format: Article
Language:English
Subjects:
alpha-Defensins - metabolism
Amino Acid Sequence
Animals
Base Sequence
Calcium - physiology
Cloning, Molecular
DNA, Complementary - genetics
Exons
Humans
Intermediate-Conductance Calcium-Activated Potassium Channels
Intestine, Small - cytology
Introns
Mice
Paneth Cells - physiology
Potassium Channels - genetics
Potassium Channels - physiology
Potassium Channels, Calcium-Activated
Transcription, Genetic
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Paneth cells in small intestinal crypts secrete microbicidal α-defensins in response to bacteria and bacterial antigens (Ayabe, T., Satchell, D. P., Wilson, C. L., Parks, W. C., Selsted, M. E., and Ouellette, A. J. (2000)Nat. Immunol. 1, 113–138). We now report that the Ca2+-activated K+ channel mIKCa1 modulates mouse Paneth cell secretion. mIKCa1 cDNA clones identified in a mouse small intestinal crypt library by hybridization to human IKCa1 cDNA probes were isolated, and DNA sequence analysis showed that they were identical to mIKCa1 cDNAs isolated from erythroid cells and liver. The genomic organization was found to be conserved between mouse and human IKCa1 as shown by comparisons of the respective cDNA and genomic sequences. Reverse transcriptase-PCR experiments using nested primers amplified mIKCa1 from the lower half of bisected crypts and from single Paneth cells, but not from the upper half of bisected crypts, villus epithelium, or undifferentiated crypt epithelial cells, suggesting a lineage-specific role for mIKCa1 in mouse small bowel epithelium. The cloned mIKCa1 channel was calcium-activated and was blocked by ten structurally diverse peptide and nonpeptide inhibitors with potencies spanning 9 orders of magnitude and indistinguishable from that of the human homologue. Consistent with channel blockade, charybdotoxin, clotrimazole, and the highly selective IKCa1 inhibitors, TRAM-34 and TRAM-39, inhibited (∼50%) Paneth cell secretion stimulated by bacteria or bacterial lipopolysaccharide, measured both as bactericidal activity and secreted cryptdin protein, but the inactive analog, TRAM-7, did not block secretion. These results demonstrate that mIKCa1 is modulator of Paneth cell α-defensin secretion and disclose an involvement in mucosal defense of the intestinal epithelium against ingested bacterial pathogens.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M107507200