Substance P stimulates cyclooxygenase-2 and prostaglandin E2 expression through JAK-STAT activation in human colonic epithelial cells.

Abstract

Substance P (SP) via its neurokinin-1 receptor (NK-1R) regulates several gastrointestinal functions. We previously reported that NK-1R-mediated chloride secretion in the colon involves formation of PG. PGE2 biosynthesis is controlled by cyclooxygenase-1 (COX-1) and COX-2, whose induction involves the STATs. In this study, we examined whether SP stimulates PGE2 production and COX-2 expression in human nontransformed NCM460 colonocytes stably transfected with the human NK-1R (NCM460-NK-1R cells) and identified the pathways involved in this response. SP exposure time and dose dependently induced an early (1-min) phosphorylation of JAK2, STAT3, and STAT5, followed by COX-2 expression and PGE2 production by 2 h. Pharmacologic experiments showed that PGE2 production is dependent on newly synthesized COX-2, but COX-1 protein. Inhibition of protein kinase Ctheta (PKCtheta), but not PKCepsilon and PKCdelta, significantly reduced SP-induced COX-2 up-regulation, and JAK2, STAT3, and STAT5 phosphorylation. Pharmacological blockade of JAK inhibited SP-induced JAK2, STAT3, and STAT5 phosphorylation; COX-2 expression; and PGE2 production. Transient transfection with JAK2 short-interferring RNA reduced COX-2 promoter activity and JAK2 phosphorylation, while RNA interference of STAT isoforms showed that STAT5 predominantly mediates SP-induced COX-2 promoter activity. Site-directed mutation of STAT binding sites on the COX-2 promoter completely abolished COX-2 promoter activity. Lastly, COX-2 expression was elevated in colon of mice during experimental colitis, and this effect was normalized by administration of the NK-1R antagonist CJ-12,255. Our results demonstrate that SP stimulates COX-2 expression and PGE2 production in human colonocytes via activation of the JAK2-STAT3/5 pathway.

• Authors: Hon-Wai Koon, Dezheng Zhao, Yanai Zhan, Sang Hoon Rhee, Mary P Moyer, Charalabos Pothoulakis
• Journal: Journal of immunology (Baltimore, Md. : 1950) (J Immunol) Vol. 176 Issue 8 Pg. 5050-9 (Apr 15 2006) ISSN: 0022-1767 [Print] United States
• PMID: 16585602 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Neurokinin-1 Receptor Antagonists
• Proto-Oncogene Proteins
• Receptors, Neurokinin-1
• STAT Transcription Factors
• STAT3 Transcription Factor
• STAT3 protein, human
• STAT5 Transcription Factor
• Substance P
• DNA
• Cyclooxygenase 2
• Protein-Tyrosine Kinases
• JAK2 protein, human
• Jak2 protein, mouse
• Janus Kinase 2
• Dinoprostone

Topics

• Animals
• Base Sequence
• Binding Sites (genetics)
• Cell Line
• Colon (drug effects, metabolism)
• Cyclooxygenase 2 (genetics, metabolism)
• DNA (genetics, metabolism)
• Dinoprostone (biosynthesis)
• Epithelial Cells (drug effects, metabolism)
• Humans
• Janus Kinase 2
• Male
• Mice
• Mice, Inbred C57BL
• Mutagenesis, Site-Directed
• Neurokinin-1 Receptor Antagonists
• Promoter Regions, Genetic
• Protein-Tyrosine Kinases (metabolism)
• Proto-Oncogene Proteins (metabolism)
• Receptors, Neurokinin-1 (metabolism)
• STAT Transcription Factors (metabolism)
• STAT3 Transcription Factor (metabolism)
• STAT5 Transcription Factor (metabolism)
• Signal Transduction (drug effects)
• Substance P (pharmacology)