Dectin-2 is a Syk-coupled pattern recognition receptor crucial for Th17 responses to fungal infection

Robinson, Matthew; Osorio, Fabiola; Rosas, Marcela; Freitas, Rui P.; Schweighoffer, Edina; Groß, Olaf; Verbeek, J. Sjef; Ruland, Jürgen; Tybulewicz, Victor L. J.; Brown, Gordon D.; Moita, Luís; Taylor, Philip R.; Sousa, Caetano Reis e

doi:10.1083/jcb1865oia9

Cited by 109 publications

(182 citation statements)

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“…These findings are in line with reports in platelets showing that CLEC-2 signals lead to PLCg activation, an enzyme crucial for intracellular calcium increase [18,19]. The use of mAbs to selective trigger surface receptors has provided important insight into the signaling and function of different CLRs [40][41][42]. Furthermore, human CLEC-2 signaling in platelets has also been studied upon crosslinking by polyclonal antibodies [19] and our own 17D9 mAb has also been used by others to selectively trigger CLEC-2 signaling in mouse platelets [20,43].…”

Section: Discussionsupporting

confidence: 89%

“…Cell lysates were prepared as described previously [40] and proteins were analyzed by immunoblotting with anti-phospho Syk (Tyr352)/ Zap70 (Tyr319) (Cell Signaling) or anti-mouse Syk (kind gift from Victor Tybulewicz), followed by suitable HRP-conjugated secondary reagent and an enhanced chemiluminescence kit (Thermo Fisher Scientific).…”

Section: Western Blottingmentioning

confidence: 99%

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CLEC‐2 signaling via Syk in myeloid cells can regulate inflammatory responses

et al. 2011

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Myeloid cells express a plethora of C-type lectin receptors (CLRs) that can regulate immune responses. CLEC-2 belongs to the Dectin-1 sub-family of CLRs that possess an extracellular C-type lectin-like domain and a single intracellular hemITAM motif. CLEC-2 is highly expressed on mouse and human platelets where it signals via Syk to promote aggregation. We generated a monoclonal antibody (mAb) against mouse CLEC-2 and found that CLEC-2 is additionally widely expressed on leukocytes and that its expression is upregulated during inflammation. MAb-mediated crosslinking of CLEC-2 leads to hemI-TAM-dependent signaling via Syk, Ca 21 and NFAT and, in myeloid cells, modulates the effect of toll-like receptor (TLR) agonists to selectively potentiate production of IL-10. A macrophage/dendritic cell-dependent increase in IL-10 is also observed in mice given anti-CLEC-2 mAb together with LPS. Collectively, these data indicate that CLEC-2 is expressed in myeloid cells and acts as a Syk-coupled CLR able to modulate TLR signaling and inflammatory responses.Key words: CLEC-2 . C-type lectin . HemITAM . IL-10 . Syk Supporting Information available online IntroductionSignaling by some members of the C-type lectin receptor (CLR) superfamily plays a key role in innate immunity and in regulation of myeloid cell function [1,2]. A classical example is Dectin-1, which is expressed by macrophages (MØs), neutrophils and dendritic cells (DCs) and acts as a pattern recognition receptor for b-glucans present on fungal and some bacterial cell walls. Dectin-1 signals via a phospho-tyrosine-based hemITAM motif in its intracellular domain that recruits spleen tyrosine kinase (Syk) [3,4]. Dectin-1 signaling through Syk in myeloid cells can variably lead to phagocytosis, production of reactive oxygen species (ROS) and/or induction of innate response genes, including those encoding pro-inflammatory cytokines [5,6]. 3040Pro-inflammatory Dectin-1 signaling requires CARD9-dependent activation of NF-kB [7] although Dectin-1 can also signal to NF-kB via a Syk-independent pathway [8]. Although many DC types are potently activated by Dectin-1 agonists, in other myeloid cells Dectin-1 signaling only weakly activates the proinflammatory gene program [9]. In those cells, Dectin-1 acts primarily in synergy with other innate immune receptors such as toll-like receptors (TLRs) [10,11]. Notably, both Dectin-1 and CARD9 are important for resistance to fungal infection in both mice [7,12,13] and humans [14,15], indicating the importance of the CLR/Syk signaling pathway in immunity.The features of Dectin-1, including type II membrane topology, single Dectin-1-like C-type lectin-like domain and intracellular hemITAM are shared by two other CLRs, DNGR-1 (CLEC9A) and CLEC-2 (CLEC1B). DNGR-1 is selectively expressed by DCs and acts as a receptor for dead cells, facilitating cross-priming to cell-associated antigens [16]. CLEC-2 was first identified in a screen for natural killer (NK) cell receptors and its mRNA was found in myeloid cells and in some NK-cell clones [...

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Section: Discussionsupporting

confidence: 89%

Section: Western Blottingmentioning

confidence: 99%

CLEC‐2 signaling via Syk in myeloid cells can regulate inflammatory responses

et al. 2011

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“…Recently, Dectin-2 [36,37] has been shown to also be important for host response to C. albicans. Nevertheless, our finding sheds light on the cooperation of different and/or similar types of PRRs in innate responses.…”

Section: Discussionmentioning

confidence: 99%

C‐type lectin SIGNR1 enhances cellular oxidative burst response against C. albicans in cooperation with Dectin‐1

et al. 2011

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We investigated the role of SIGNR1 in the recognition of Candida albicans and the subsequent cellular oxidative burst response. Soluble SIGNR1 (sSIGNR1) tetramer bound equally to zymosan and both heat-killed (HK) and live C. albicans in an EDTA-sensitive manner, whereas sDectin-1 tetramer predominantly bound to zymosan and HK-microbes in an EDTA-independent manner. In cellular response, enhanced oxidative burst was observed in RAW264.7 cells expressing SIGNR1 (RAW-SIGNR1) compared with RAW-control cells upon stimulation with HK-C. albicans and zymosan. This response was independent of TLR2 and the cytosolic portion of SIGNR1 but dependent on the recognition by SIGNR1 via carbohydrate recognition domain. Antagonistic laminarin and anti-Dectin-1 mAb cooperatively reduced the response with mannan and anti-SIGNR1 mAb, respectively, although they had no effect by themselves. Moreover, oxidative response and bactericidal activity largely relied on Syk-mediated signaling. RAW-SIGNR1 cells not only captured microbes more efficiently but also showed higher responses than RAW-control cells. Similar enhanced responses were observed in SIGNR-1-expressing resident peritoneal M/. Interestingly, Dectin-1 was recruited to the phagosomal membrane upon the stimulation and physically associated with SIGNR1. These results suggest that SIGNR1 plays a significant role in inducing oxidative response to C. albicans by Syk-dependent signaling, possibly through Dectin-1.Key words: C. albicans . Dectin-1 . Macrophages . SIGNR1 . TLR2 IntroductionInnate immunity is a crucial host defense system that eliminates pathogens as they initiate an infection and leads to the subsequent initiation of the adaptive immune response [1]. The system consists of germline-encoded genes, i.e. toll-like receptors (TLRs) [2] [8][9][10][11][12]. Microbe-mediated stimulation of Dectin-1 results in cellular oxidative burst and cytokine production through its ITAM and the Syk kinase pathway [13,14]. In addition, Dectin-1 has been shown to function collaboratively with TLR2 to stimulate cytokine production [15] and Th17/Treg induction [16].hDC-SIGN recognizes mannose and fucose moieties in the surface of a variety of microbes and viruses, such as Mycobacteria, Leishmania, Salmonella, Candida species, HIV, HCV, dengue virus, CMV, Ebola virus and Sindbis virus (refer to [17]). However, pathogens, i.e. HIV and HCV, have also found ways to subvert and use hDC-SIGN to their advantage [18,19]. Mycobacterium tuberculosis and HIV also target hDC-SIGN in order to upregulate DC production of the immunosuppressive cytokine IL-10 through Raf-1 kinase activation, which induces acetylation of the NF-kB p65 subunit in the presence of co-signaling from TLR4 [20].Mice have eight hDC-SIGN homologues [21,22]. One of these homologues, SIGNR1, has been shown to be expressed on particular Mf subsets in the marginal zone of the spleen, medulla of the lymph nodes and the peritoneal cavity [23][24][25] and to possess mannosebinding activities like hDC-SIGN. SIGNR1 recognizes not only vari...

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“…11 Syk is involved in Tc lineage commitment as it was shown in response to fungal signaling via Dectin for Th17 responses. 12 This could be relevant as Th17 responses were shown to be involved in GvHD. 13 The application of Syk inhibitors has been successfully tested in murine models of glomerulonephritis, 14 lupus 15,16 and rheumatoid arthritis.…”

Section: Introductionmentioning

confidence: 99%

Spleen tyrosine kinase (Syk) is a potent target for GvHD prevention at different cellular levels

Leonhardt

Zirlik²,

Buchner

et al. 2012

Leukemia

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Dectin-2 is a Syk-coupled pattern recognition receptor crucial for Th17 responses to fungal infection

Abstract: Innate immune cells detect pathogens via pattern recognition receptors (PRRs),

Cited by 109 publications

References 52 publications

CLEC‐2 signaling via Syk in myeloid cells can regulate inflammatory responses

CLEC‐2 signaling via Syk in myeloid cells can regulate inflammatory responses

C‐type lectin SIGNR1 enhances cellular oxidative burst response against C. albicans in cooperation with Dectin‐1

Spleen tyrosine kinase (Syk) is a potent target for GvHD prevention at different cellular levels

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