Modulation of mouse paneth cell α-defensin secretion by mIKCa1, a Ca2+-activated, intermediate conductance potassium channel

Tokiyoshi Ayabe, Heike Wulff, Dalila Darmoul, Michael D. Cahalan, K. George Chandy, Andre J. Ouellette

Research output: Contribution to journalArticle

64 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
Pages (from-to)3793-3800
Number of pages8
JournalJournal of Biological Chemistry
Volume277
Issue number5
DOIs
StatePublished - Feb 1 2002

Fingerprint

Paneth Cells
Defensins
Potassium Channels
Complementary DNA
Modulation
Bacteria
Charybdotoxin
Clotrimazole
Bacterial Antigens
Calcium-Activated Potassium Channels
Epithelium
DNA sequences
RNA-Directed DNA Polymerase
Pathogens
Erythroid Cells
Liver
Modulators
Lipopolysaccharides
Calcium Channels
Intestinal Mucosa

ASJC Scopus subject areas

  • Biochemistry

Cite this

Modulation of mouse paneth cell α-defensin secretion by mIKCa1, a Ca2+-activated, intermediate conductance potassium channel. / Ayabe, Tokiyoshi; Wulff, Heike; Darmoul, Dalila; Cahalan, Michael D.; George Chandy, K.; Ouellette, Andre J.

In: Journal of Biological Chemistry, Vol. 277, No. 5, 01.02.2002, p. 3793-3800.

Research output: Contribution to journalArticle

Ayabe, Tokiyoshi ; Wulff, Heike ; Darmoul, Dalila ; Cahalan, Michael D. ; George Chandy, K. ; Ouellette, Andre J. / Modulation of mouse paneth cell α-defensin secretion by mIKCa1, a Ca2+-activated, intermediate conductance potassium channel. In: Journal of Biological Chemistry. 2002 ; Vol. 277, No. 5. pp. 3793-3800.
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