Maintenance of colonic homeostasis by distinctive apical TLR9 signalling in intestinal epithelial cells.
Nat Cell Biol
; 8(12): 1327-36, 2006 Dec.
Article
en En
| MEDLINE
| ID: mdl-17128265
ABSTRACT
The mechanisms by which commensal bacteria suppress inflammatory signalling in the gut are still unclear. Here, we present a cellular mechanism whereby the polarity of intestinal epithelial cells (IECs) has a major role in colonic homeostasis. TLR9 activation through apical and basolateral surface domains have distinct transcriptional responses, evident by NF-kappaB activation and cDNA microarray analysis. Whereas basolateral TLR9 signals IkappaBalpha degradation and activation of the NF-kappaB pathway, apical TLR9 stimulation invokes a unique response in which ubiquitinated IkappaB accumulates in the cytoplasm preventing NF-kappaB activation. Furthermore, apical TLR9 stimulation confers intracellular tolerance to subsequent TLR challenges. IECs in TLR9-deficient mice, when compared with wild-type and TLR2-deficient mice, display a lower NF-kappaB activation threshold and these mice are highly susceptible to experimental colitis. Our data provide a case for organ-specific innate immunity in which TLR expression in polarized IECs has uniquely evolved to maintain colonic homeostasis and regulate tolerance and inflammation.
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Banco de datos:
MEDLINE
Asunto principal:
Transducción de Señal
/
Polaridad Celular
/
Colon
/
Enterocitos
/
Receptor Toll-Like 9
/
Homeostasis
Límite:
Animals
/
Humans
Idioma:
En
Año:
2006
Tipo del documento:
Article