Strategic compartmentalization of Toll-like receptor 4 in the mouse gut.
Pattern recognition receptors (PRRs), which include the Toll-like receptors (TLRs), are involved in the innate immune response to infection. TLR4 is a model for the TLR family and is the main LPS receptor. We wanted to determine the expression of TLR4 and compare it with that of TLR2 and CD14 along the gastrointestinal mucosa of normal and colitic BALB/c mice. Colitis was induced with 2.5% dextran sodium sulfate (DSS). Mucosa from seven segments of the digestive tract (stomach, small intestine in three parts, and colon in three parts) was isolated by two different methods. Mucosal TLR4, CD14, TLR2, MyD88, and IL-1beta mRNA were semiquantified by Northern blotting. TLR4 protein was determined by Western blotting. TLR4/MD-2 complex and CD14 were evaluated by immunohistochemistry. PRR genes were constitutively expressed and were especially stronger in colon. TLR4 and CD14 mRNA were increased in the distal colon, but TLR2 mRNA was expressed more strongly in the proximal colon, and MyD88 had a uniform expression throughout the gut. Accordingly, TLR4 and CD14 protein levels were higher in the distal colon. TLR4/MD-2 and CD14 were localized at crypt bottom epithelial cells. TLR4/MD2, but not CD14, was found in mucosal mononuclear cells. Finally, DSS-induced inflammation was localized in the distal colon. All genes studied were up-regulated during DSS-induced inflammation, but the normal colon-stressed gut distribution was preserved. Our findings demonstrate that TLR4, CD14, and TLR2 are expressed in a compartmentalized manner in the mouse gut and provide novel information about the in vivo localization of PRRs.
Ortega-Cava
Cesar F
CF
Department of Internal Medicine II, Shimane Medical University, Izumo, Japan. ortega@shimane-med.ac.jp
Ishihara
Shunji
S
Rumi
Mohammad A K
MA
Kawashima
Kousaku
K
Ishimura
Norihisa
N
Kazumori
Hideaki
H
Udagawa
Jun
J
Kadowaki
Yasunori
Y
Kinoshita
Yoshikazu
Y
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000943:Antigens, Differentiation / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D000950:Antigens, Ly / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D015152:Blotting, Northern; D003092:Colitis / Q000139:chemically induced / Q000276:immunology / Q000473:pathology; D003106:Colon / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D016264:Dextran Sulfate / Q000633:toxicity; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000276:immunology; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D018950:Lipopolysaccharide Receptors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D051218:Lymphocyte Antigen 96; D046911:Macromolecular Substances; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D023421:Models, Animal; D053594:Myeloid Differentiation Factor 88; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology
D048868:Adaptor Proteins, Signal Transducing; D000943:Antigens, Differentiation; D000950:Antigens, Ly; D018950:Lipopolysaccharide Receptors; C411728:Ly96 protein, mouse; D051218:Lymphocyte Antigen 96; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D016264:Dextran Sulfate