Neutrophil transepithelial migration: role of toll-like receptors in mucosal inflammation
Mem. Inst. Oswaldo Cruz
;
100(supl.1): 191-198, Mar. 2005.
Article
Dans Anglais
| LILACS
| ID: lil-402199
RESUMO
The symptomatic phases of many inflammatory diseases are characterized by migration of large numbers of neutrophils (PMN) across a polarized epithelium and accumulation within a lumen. For example, acute PMN influx is common in diseases of the gastrointestinal system (ulcerative colitis, Crohn's disease, bacterial enterocolitis, gastritis), hepatobiliary system (cholangitis, acute cholecystitis), respiratory tract (bronchial pneumonia, bronchitis, cystic fibrosis, bronchiectasis), and urinary tract (pyelonephritis, cystitis). Despite these observations, the molecular basis of leukocyte interactions with epithelial cells is incompletely understood. In vitro models of PMN transepithelial migration typically use N-formylated bacterial peptides such as fMLP in isolation to drive human PMNs across epithelial monolayers. However, other microbial products such as lipopolysaccharide (LPS) are major constituents of the intestinal lumen and have potent effects on the immune system. In the absence of LPS, we have shown that transepithelial migration requires sequential adhesive interactions between the PMN beta2 integrin CD11b/CD18 and JAM protein family members. Other epithelial ligands appear to be abundantly represented as fucosylated proteoglycans. Further studies indicate that the rate of PMN migration across mucosal surfaces can be regulated by the ubiquitously expressed transmembrane protein CD47 and microbial-derived factors, although many of the details remain unclear. Current data suggests that Toll-like receptors (TLR), which recognize specific pathogen-associated molecular patterns (PAMPs), are differentially expressed on both leukocytes and mucosal epithelial cells while serving to modulate leukocyte-epithelial interactions. Exposure of epithelial TLRs to microbial ligands has been shown to result in transcriptional upregulation of inflammatory mediators whereas ligation of leukocyte TLRs modulate specific antimicrobial responses. A better understanding of these events will hopefully provide new insights into the mechanisms of epithelial responses to microorganisms and ideas for therapies aimed at inhibiting the deleterious consequences of mucosal inflammation.
Texte intégral:
Disponible
Indice:
LILAS (Amériques)
Sujet Principal:
Mouvement cellulaire
/
Cellules épithéliales
/
Inflammation muqueuse
/
Récepteurs de type Toll
/
Granulocytes neutrophiles
Type d'étude:
Étude pronostique
Limites du sujet:
Humains
langue:
Anglais
Texte intégral:
Mem. Inst. Oswaldo Cruz
Thème du journal:
Médecine tropicale
/
Parasitologie
Année:
2005
Type:
Article
Pays d'affiliation:
États-Unis d'Amérique
Institution/Pays d'affiliation:
Emory University/US
Documents relatifs à ce sujet
MEDLINE
...
LILACS
LIS