title: Commensal bacteria promote migration of mast cells into the intestine.
abstract: Mast cells differentiate from hematopoietic stem cells in the bone marrow and migrate via the circulation to peripheral tissues, where they play a pivotal role in induction of both innate and adaptive immune responses. In this study, the effect of intestinal commensal bacteria on the migration of mast cells into the intestine was investigated. Histochemical analyses showed that germ-free (GF) mice had lower mast cell densities in the small intestine than normal mice. It was also shown that GF mice had lower mast cell proportion out of lamina propria leukocytes in the small intestine and higher mast cell percentages in the blood than normal mice by flow cytometry. These results indicate that migration of mast cells from the blood to the intestine is promoted by intestinal commensal bacteria. In addition, MyD88⁻/⁻ mice had lower densities of intestinal mast cells than CV mice, suggesting that the promotive effect of commensals is, at least in part, TLR-dependent. The ligands of CXC chemokine receptor 2 (CXCR2), which is critical for homing of mast cells to the intestine, were expressed higher in intestinal tissues and in intestinal epithelial cells (IECs) of normal mice than in those of GF or MyD88⁻/⁻ mice. Collectively, it is suggested that commensals promote migration of mast cells into the intestine through the induction of CXCR2 ligands from IECs in a TLR-dependent manner.
authors.affiliation: Food and Physiological Functions Laboratory, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Kunii
authors.forename: Kyoko
authors.initials: K
authors.lastname: Takahashi
authors.forename: Kazumi
authors.initials: K
authors.lastname: Kasakura
authors.forename: Masato
authors.initials: M
authors.lastname: Tsuda
authors.forename: Kou
authors.initials: K
authors.lastname: Nakano
authors.forename: Akira
authors.initials: A
authors.lastname: Hosono
authors.forename: Shuichi
authors.initials: S
authors.lastname: Kaminogawa
mesh_terms: D000818:Animals; D001419:Bacteria / Q000276:immunology*; D002465:Cell Movement / Q000276:immunology*; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D007422:Intestines / Q000276:immunology* / Q000473:pathology; D008024:Ligands; D008297:Male; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88 / Q000276:immunology / Q000378:metabolism; D023063:Receptors, Interleukin-8B / Q000235:genetics / Q000378:metabolism
chemical_list: D008024:Ligands; D053594:Myeloid Differentiation Factor 88; D023063:Receptors, Interleukin-8B