Paneth cell α-defensin 6 (HD-6) is an antimicrobial peptide
Abstract
Defensins protect human barriers from commensal and pathogenic microorganisms. Human α-defensin 6 (HD-6) is produced exclusively by small intestinal Paneth cells but, in contrast to other antimicrobial peptides (AMPs) for HD-6, no direct antibacterial killing activity has been detected so far. Herein, we systematically tested how environmental factors, like pH and reducing conditions, affect antimicrobial activity of different defensins against anaerobic bacteria of the human intestinal microbiota. Remarkably, by mimicking the intestinal milieu we detected for the first time antibacterial activity of HD-6. Activity was observed against anaerobic gut commensals but not against some pathogenic strains. Antibiotic activity was attributable to the reduced peptide and independent of free cysteines or a conserved histidine residue. Furthermore, the oxidoreductase thioredoxin, which is also expressed in Paneth cells, is able to reduce a truncated physiological variant of HD-6. Ultrastructural analyses revealed that reduced HD-6 causes disintegration of cytoplasmic structures and alterations in the bacterial cell envelope, while maintaining extracellular net-like structures. We conclude that HD-6 is an antimicrobial peptide. Our data suggest two distinct antimicrobial mechanisms by one peptide: HD-6 kills specific microbes depending on the local environmental conditions, whereas known microbial trapping by extracellular net structures is independent of the reducing milieu.
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BibTeX
@article{schroeder2026paneth,
title = {{Paneth cell α-defensin 6 (HD-6) is an antimicrobial peptide}},
author = {B Schroeder and D Ehmann and J Precht and P Castillo and R Küchler and J Berger and M Schaller and E Stange and J Wehkamp},
journal = {Mucosal Immunology},
year = {2026},
month = sep,
doi = {10.1038/mi.2014.100},
url = {https://hal.science/hal-05772259v1},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Paneth cell α-defensin 6 (HD-6) is an antimicrobial peptide
AU - B Schroeder
AU - D Ehmann
AU - J Precht
AU - P Castillo
AU - R Küchler
AU - J Berger
AU - M Schaller
AU - E Stange
AU - J Wehkamp
PY - 2026
DA - 2026/09/30
JO - Mucosal Immunology
DO - 10.1038/mi.2014.100
UR - https://hal.science/hal-05772259v1
AB - Defensins protect human barriers from commensal and pathogenic microorganisms. Human α-defensin 6 (HD-6) is produced exclusively by small intestinal Paneth cells but, in contrast to other antimicrobial peptides (AMPs) for HD-6, no direct antibacterial killing activity has been detected so far. Herein, we systematically tested how environmental factors, like pH and reducing conditions, affect antimicrobial activity of different defensins against anaerobic bacteria of the human intestinal microbiota. Remarkably, by mimicking the intestinal milieu we detected for the first time antibacterial activity of HD-6. Activity was observed against anaerobic gut commensals but not against some pathogenic strains. Antibiotic activity was attributable to the reduced peptide and independent of free cysteines or a conserved histidine residue. Furthermore, the oxidoreductase thioredoxin, which is also expressed in Paneth cells, is able to reduce a truncated physiological variant of HD-6. Ultrastructural analyses revealed that reduced HD-6 causes disintegration of cytoplasmic structures and alterations in the bacterial cell envelope, while maintaining extracellular net-like structures. We conclude that HD-6 is an antimicrobial peptide. Our data suggest two distinct antimicrobial mechanisms by one peptide: HD-6 kills specific microbes depending on the local environmental conditions, whereas known microbial trapping by extracellular net structures is independent of the reducing milieu.
SN - 1933-0219
SN - 1935-3456
ER -