Substance P receptor expression in intestinal epithelium in clostridium difficile toxin A enteritis in rats.
We previously reported that the inflammatory effects of Clostridium difficile toxin A on rat intestine can be significantly inhibited with a specific neurokinin-1 receptor (NK-1R) antagonist. In this study we investigated the localization and expression of NK-1R mRNA and protein in rat intestine by in situ hybridization, Northern blot analysis, and immunohistochemistry, respectively, after exposure to toxin A. Northern blot analysis showed increased mucosal levels of NK-1R mRNA starting 30 min after toxin A administration. In situ hybridization showed that toxin A increased NK-1R mRNA expression in intestinal epithelial cells after 30, 120, and 180 min. In rats pretreated with the NK-1R antagonist CP-96345 the increase in NK-1R mRNA levels after exposure to toxin A was inhibited, indicating that NK-1R upregulation is substance P (SP) dependent. One hour after exposure to toxin A many of the intestinal epithelial cells showed staining for NK-1R compared with controls. Specific 125I-SP binding to purified epithelial cell membranes obtained from ileum exposed to toxin A for 15 min was increased twofold over control and persisted for 4 h. This report provides evidence that NK-1R expression is increased in the intestinal epithelium shortly after exposure to toxin A and may be important in toxin A-induced inflammation.
Pothoulakis
C
C
Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
Castagliuolo
I
I
Leeman
S E
SE
Wang
C C
CC
Li
H
H
Hoffman
B J
BJ
Mezey
E
E
D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity; D001713:Biphenyl Compounds / Q000494:pharmacology; D016360:Clostridioides difficile; D004751:Enteritis / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D004768:Enterotoxins / Q000633:toxicity*; D007082:Ileum; D017403:In Situ Hybridization; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology; D007700:Kinetics; D008297:Male; D014176:Protein Biosynthesis / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D018040:Receptors, Neurokinin-1 / Q000096:biosynthesis*; D013373:Substance P / Q000037:antagonists & inhibitors; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects*
D001427:Bacterial Toxins; D001713:Biphenyl Compounds; D004768:Enterotoxins; D012333:RNA, Messenger; D018040:Receptors, Neurokinin-1; C041348:tcdA protein, Clostridium difficile; D013373:Substance P; C066892:CP 96345