Differential expression of human alpha- and beta-defensins mRNA in gastrointestinal epithelia.
BACKGROUND
While defensins have received great attention for their role in bronchial innate immune defence, little is known about the expression levels of the four human epithelial defensins (HD5, HD6, hBD1 and hBD2) in the digestive tract. In this study we quantified the alpha- and beta-defensins mRNA in biopsies obtained from the gastrointestinal mucosa and identified the cells expressing the beta-defensin hBD1 mRNA in ileal mucosa.


METHODS
Biopsies from human stomach (corpus and antrum), duodenum, jejunum, ileum and colon were analysed for their expression of alpha- and beta-defensins. The mRNA of defensins was quantified by semiquantitative reverse transcription-polymerase chain reaction. Cells expressing beta-defensin hBD1 mRNA were identified by in situ hybridization with 35S-labelled RNA probes in tissue sections of human ileum.


RESULTS
The hBD1 mRNA was expressed at low levels with little variability throughout the gastrointestinal tract and was detected in all epithelial cells of ileal mucosa. HD5 and HD6 mRNA expression was restricted to the intestine and displayed high interindividual variability. The highest expression levels were observed in jejunum and ileum. Biopsies obtained from duodenum displayed low levels or no expression of HD5 and HD6. The expression level increased considerably in a biopsy obtained from a patient with acute coeliac sprue. In contrast, low levels were observed in a biopsy from a patient with coeliac sprue in remission.


CONCLUSIONS
The expression levels of hBD1, HD5 and HD6 throughout the gastrointestinal tract are tissue and peptide specific and these defensins are expressed with high interindividual variability.
Frye
M
M
Institute for Anthropology and Human Genetics, Johann Wolfgang Goethe-University, Frankfurt, Germany.
Bargon
J
J
Lembcke
B
B
Wagner
T O
TO
Gropp
R
R
D000890:Anti-Infective Agents / Q000378:metabolism*; D003106:Colon / Q000166:cytology / Q000378:metabolism; D005753:Gastric Mucosa / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D017403:In Situ Hybridization; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D007421:Intestine, Small / Q000166:cytology / Q000378:metabolism; D008407:Mast Cells / Q000166:cytology; D022423:Myeloid Cells / Q000166:cytology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D023084:alpha-Defensins / Q000096:biosynthesis* / Q000235:genetics; D023083:beta-Defensins / Q000096:biosynthesis* / Q000235:genetics
D000890:Anti-Infective Agents; D012333:RNA, Messenger; D023084:alpha-Defensins; D023083:beta-Defensins