| 1. |
- Abonia, J Pablo, et al.
(författare)
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Alpha-4 integrins and VCAM-1, but not MAdCAM-1, are essential for recruitment of mast cell progenitors to the inflamed lung
- 2006
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 108:5, s. 1588-1594
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Tidskriftsartikel (refereegranskat)abstract
- Normal mouse lungs lack appreciable numbers of mast cells (MCs) or MC progenitors (MCp's), yet the appearance of mature MCs in the tracheobronchial epithelial surface is a characteristic of allergic, T-cell-dependent pulmonary inflammation. We hypothesized that pulmonary inflammation would recruit MCp's to inflamed lungs and that this recruitment would be regulated by distinct adhesion pathways. Ovalbumin-sensitized and challenged mice had a greater than 28-fold increase in the number of MCp's in the lungs. In mice lacking endothelial vascular cell adhesion molecule 1 (VCAM-1) and in wild-type mice administered blocking monoclonal antibody (mAb) to VCAM-1 but not to mucosal addressin CAM-1 (MadCAM-1), recruitment of MCp's to the inflamed lung was reduced by greater than 75%. Analysis of the integrin receptors for VCAM-1 showed that in beta7 integrin-deficient mice, recruitment was reduced 73% relative to wild-type controls, and in either BALB/c or C57BL/6 mice, mAb blocking of alpha4, beta1, or beta7 integrins inhibited the recruitment of MCp's to the inflamed lung. Thus, VCAM-1 interactions with both alpha4beta1 and alpha4beta7 integrins are essential for the recruitment and expansion of the MCp populations in the lung during antigen-induced pulmonary inflammation. Furthermore, the MCp is currently unique among inflammatory cells in its partial dependence on alpha4beta7 integrins for lung recruitment.
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| 2. |
- Alcaide, Pilar, et al.
(författare)
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Dendritic cell expression of the transcription factor T-bet regulates mast cell progenitor homing to mucosal tissue
- 2007
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Ingår i: Journal of Experimental Medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 204:2, s. 431-439
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Tidskriftsartikel (refereegranskat)abstract
- The transcription factor T-bet was identified in CD4(+) T cells, and it controls interferon gamma production and T helper type 1 cell differentiation. T-bet is expressed in certain other leukocytes, and we recently showed (Lord, G.M., R.M. Rao, H. Choe, B.M. Sullivan, A.H. Lichtman, F.W. Luscinskas, and L.H. Glimcher. 2005. Blood. 106:3432-3439) that it regulates T cell trafficking. We examined whether T-bet influences homing of mast cell progenitors (MCp) to peripheral tissues. Surprisingly, we found that MCp homing to the lung or small intestine in T-bet(-/-) mice is reduced. This is reproduced in adhesion studies using bone marrow-derived MCs (BMMCs) from T-bet(-/-) mice, which showed diminished adhesion to mucosal addresin cellular adhesion molecule-1 (MAdCAM-1) and vascular cell adhesion molecule-1 (VCAM-1), endothelial ligands required for MCp intestinal homing. MCp, their precursors, and BMMCs do not express T-bet, suggesting that T-bet plays an indirect role in homing. However, adoptive transfer experiments revealed that T-bet expression by BM cells is required for MCp homing to the intestine. Furthermore, transfer of WT BM-derived dendritic cells (DCs) to T-bet(-/-) mice restores normal MCp intestinal homing in vivo and MCp adhesion to MAdCAM-1 and VCAM-1 in vitro. Nonetheless, T-bet(-/-) mice respond vigorously to intestinal infection with Trichinella spiralis, eliminating a role for T-bet in MC recruitment to sites of infection and their activation and function. Therefore, remarkably, T-bet expression by DCs indirectly controls MCp homing to mucosal tissues.
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| 3. |
- Nigrovic, Peter A, et al.
(författare)
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Genetic inversion in mast cell-deficient (W(sh)) mice interrupts corin and manifests as hematopoietic and cardiac aberrancy.
- 2008
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Ingår i: The American journal of pathology. - : Elsevier BV. - 0002-9440. ; 173:6, s. 1693-1701
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Tidskriftsartikel (refereegranskat)abstract
- Mast cells participate in pathophysiological processes that range from antimicrobial defense to anaphylaxis and inflammatory arthritis. Much of the groundwork for the understanding of mast cells was established in mice that lacked mast cells through defects in either stem cell factor or its receptor, Kit. Among available strains, C57BL/6-Kit(W-sh) (W(sh)) mice are experimentally advantageous because of their background strain and fertility. However, the genetic inversion responsible for the W(sh) phenotype remains poorly defined, and its effects beyond the mast cell have been incompletely characterized. We report that W(sh) animals exhibit splenomegaly with expanded myeloid and megakaryocyte populations. Hematopoietic abnormalities extend to the bone marrow and are reflected by neutrophilia and thrombocytosis. In contrast, mast cell-deficient WBB6F1-Kit(W)/Kit(W-v) (W/W(v)) mice display mild neutropenia, but no changes in circulating platelet numbers. To help define the basis for the W(sh) phenotype, a "DNA walking" strategy was used to identify the precise location of the 3' breakpoint, which was found to reside 67.5 kb upstream of Kit. The 5' breakpoint disrupts corin, a cardiac protease responsible for the activation of atrial natriuretic peptide. Consistent with this result, transcription of full-length corin is ablated and W(sh) mice develop symptoms of cardiomegaly. Studies performed using mast cell-deficient strains must consider the capacity of associated abnormalities to either expose or compensate for the missing mast cell lineage.
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