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...pressed. The findings of these studies are summarized in Table 2. The TLRs appear to be widely expressed by murine mast cells, with expression of TLR1–4 and 6–9 identified at least at the mRNA level (=-=McCurdy et al., 2001-=-; Supajatura et al., 2001; Masuda et al., 2002; Ikeda and Funaba, 2003; Matsushima et al., 2004; Li et al., 2009; Mrabet-Dahbi et al., 2009). Expression of TLR5 has not been demonstrated on murine mas...

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...ent. Interestingly, the production of cytokines by mast cells after TLR-4 stimulation was not associated with mast cell degranulation (Ikeda and Funaba, 2003; Matsushima et al., 2004; Qiao et al., 2006; Supajatura et al., 2001, 2002), since it failed to induce an increase in intracellular calcium levels (Qiao et al., 2006). There are apparently conflicting reports regarding the cytokine repertoire released by mast cells after TLR-4 stimulation. On one hand, LPS reportedly stimulated mouse BMMCs to produce proinflammatory cytokines such as TNF-a, IL-1b, IL-6 and IL-13 (Matsushima et al., 2004; McCurdy et al., 2001; Supajatura et al., 2001, 2002). Similar results were obtained using the murine MC/9 mast cell line (McCurdy et al., 2001) and fetal skin-derived mast cells (FSMC) (Matsushima et al., 2004). LPS stimulation of BMMCs, furthermore, led to ARTICLE IN PRESS Table 1. TLRs expression and function on murine mast cells Toll-like receptor Ligand Studied in Result of mast cell-TLR activation References In vitro In vivo TLR1 Lipopeptide FSMC Not studied 1 TLR2 Peptidoglycan (PGN) MC/9, BMMC TNF-a, IL-4, IL-5, IL-6, IL13, IL-1ba Activation of skin MC 2, 3, 4 BMMC Pro-MMP-9 5 No degranulation MC/9, BMMC S...

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...mune cell activation, we chose to focus on the TLRs (5, 12, 56), TLR2 and TLR4, since both of these TLRs have previously been shown to be expressed by MCs and shown to have a functional impact on MCs =-=(36, 55)-=-. TLR2 is a receptor for PGN, i.e., a main component of the cell wall of Gram-positive bacteria, but it should be stressed that TLR2 also recognizes a number of additional ligands (64). TLR4, on the o...

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....g. THP-1).sAlso, there is evidence for expression ofsthese receptors on bone marrow-derived mast cells, which can regulate severalscomponents of the innate immune response to pathogens and allergens =-=(67;68)-=-.sPrior toswork in this thesis, there was limited information about TLR2 and TLR4 expression onsprimary human mononuclear phagocytes, particularly during monocyte differentiationsinto macrophages (69-...

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...eated sample (black arrow), and new, faint bands in the DPPI-treated sample (arrowheads). 634 The Journal of Clinical Investigation |February 2004 |Volume 113 |Number 4 hypothesized importance of mMCP-6 (and possibly other tryptases) is attractive not only because of this study’s observation that it hydrolyzes IL-6 in vitro but because levels of active mMCP-6 are sharply reduced in mast cells of DPPI–/– mice (12). Thus, we propose that the following sequence of events occurs in the setting of an infection: Bacteria activate mast cells, stimulating secretion of cytokines such as TNF-α and IL-6 (5, 36). Secreted TNF-α aids in recruiting neutrophils to the site of infection. At the same time, activated mast cells release tryptases, which reduce IL-6 levels via proteolytic inactivation. Because IL-6 is beneficial at certain times during the septic response, inactivation by tryptase is harmful, and if levels drop below a critical threshold, the animal dies. For the individual host, the net harm or benefit of mast cell products depends on the balance of these opposing processes. Whether similar processes occur for other mediators untested in this model is unknown. In summary, the data presented...

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...sed by anti-TLR2 or anti-TLR4 antibodies. What is more, by the use of flow cytometry technique, we also stated that rat peritoneal mast cells do not express CD14 molecules. Previously, McCurdy et al. =-=[23]-=- and Stassen et al. [36] demonstrated lack of CD14 protein expression on the surface of murine bone marrow-derived mast cells (BMMCs) and Varadaradjalou et al. [29] did not notice surface CD14 molecul...

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...plicate by differences of Ct numbers, as described in Materials and Methods. Data are representative of three independent experiments.534 TLR EXPRESSION PROFILES AND FUNCTIONS OF MAST CELLS and TLR4 =-=(41, 42)-=-. We first compared TLR mRNA expression profiles between FSMC and BMMC using RT-PCR. FSMC strongly expressed TLR1, TLR3, and TLR7 mRNA, and modestly expressed TLR9 mRNA, whereas BMMC reproducibly show...

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...04). Murine connective tissue typeMCs express TLR3,TLR7,andTLR9 mRNA. In contrast, BMMCs onlymarginally express TLR3, TLR7, and TLR9 mRNA (Matsushima et al., 2004). Human MCs also express TLR1 and 6 (=-=McCurdy et al., 2001-=-, 2003), TLR3 (Kulka et al., 2004), TLR7 (Kulka et al., 2004; Matsushima et al., 2004), and TLR9 (Zhu and Marshall, 2001) whereas the expression of TLR5 by MCs remains controversial. Other than TLRs, ...

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...otein: hCBMC and nasal polyps MC (McCurdy et al., 2003). TLR2 and TLR4 protein:murine intestine MC and murine and rat peritoneal MC (Pietrzak et al., 2011) de novo synthesis and release of cytokines (=-=McCurdy et al., 2001-=-; Supajatura et al., 2002) CD48 2B4, FimH, S. aureus, and M. tuberculosis toxins Glycosyl-phosphatidyl-inositol (GPI)-anchored protein Protein: BMMC and human peripheral blood MC Allergic effector uni...