Differential expression of neurokinin-1 receptor by human mucosal and peripheral lymphoid cells.
Substance P (SP) has been implicated in peripheral and mucosal neuroimmunoregulation. However, confusion remains regarding immunocyte expression of the receptor for SP, neurokinin-1 receptor (NK-1R), and whether there is differential NK-1R expression in the mucosal versus the peripheral immune system. In the same assay systems, we examined the expression of NK-1R in human lamina propria mononuclear cells (LPMC), peripheral blood mononuclear cells (PBMC), peripheral blood lymphocytes (PBL), monocytes, and monocyte-derived macrophages (MDM). Using standard reverse transcription (RT)-PCR, mRNA expression of both the long and the short isoforms of the NK-1R was evident in LPMC but not in PBMC, PBL, monocytes, or MDM. However, by using nested RT-PCR NK-1R mRNA expression was detected in PBMC, PBL, monocytes, and MDM. This level of expression was found to represent one NK-1R mRNA transcript in >1,000 cells. In contrast, by using competitive RT-PCR we demonstrate that LPMC express a more biologically significant level of eight NK-1R mRNA transcripts per cell. Flow cytometric detection of NK-1R expression at the protein level was evident in LPMC but not in PBMC. These findings illustrate the extreme sensitivity of nested RT-PCR and the advantages of competitive RT-PCR in comparative studies of receptor expression in different cell populations. This study suggests that, under normal conditions, readily detectable expression of NK-1R in human mononuclear cells occurs at the mucosal level rather than in the peripheral circulation.
Goode
T
T
Department of Medicine, National University of Ireland, Cork, Ireland.
O'Connell
J
J
Ho
W Z
WZ
O'Sullivan
G C
GC
Collins
J K
JK
Douglas
S D
SD
Shanahan
F
F
D000230:Adenocarcinoma / Q000276:immunology* / Q000473:pathology; D002460:Cell Line; D003106:Colon / Q000737:chemistry / Q000276:immunology / Q000473:pathology; D003110:Colonic Neoplasms / Q000276:immunology* / Q000473:pathology; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic / Q000276:immunology; D006801:Humans; D007413:Intestinal Mucosa / Q000737:chemistry / Q000276:immunology / Q000473:pathology; D008214:Lymphocytes / Q000737:chemistry / Q000166:cytology / Q000276:immunology; D017737:Macrophages, Peritoneal / Q000737:chemistry / Q000166:cytology / Q000276:immunology; D009000:Monocytes / Q000737:chemistry / Q000166:cytology / Q000276:immunology*; D012333:RNA, Messenger / Q000032:analysis; D018040:Receptors, Neurokinin-1 / Q000032:analysis* / Q000235:genetics*
D012333:RNA, Messenger; D018040:Receptors, Neurokinin-1