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

2009 ◽  
Vol 206 (9) ◽  
pp. 2037-2051 ◽  
Author(s):  
Matthew J. Robinson ◽  
Fabiola Osorio ◽  
Marcela Rosas ◽  
Rui P. Freitas ◽  
Edina Schweighoffer ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Immune Responses ◽  
Fungal Infection ◽  
Signaling Pathway ◽  
Innate Immune ◽  
Adaptive Immune ◽  
Immune Resistance ◽  
Syk Kinase ◽  
Fungal Particles ◽  
Recognition Receptor

Innate immune cells detect pathogens via pattern recognition receptors (PRRs), which signal for initiation of immune responses to infection. Studies with Dectin-1, a PRR for fungi, have defined a novel innate signaling pathway involving Syk kinase and the adaptor CARD9, which is critical for inducing Th17 responses to fungal infection. We show that another C-type lectin, Dectin-2, also signals via Syk and CARD9, and contributes to dendritic cell (DC) activation by fungal particles. Unlike Dectin-1, Dectin-2 couples to Syk indirectly, through association with the FcRγ chain. In a model of Candida albicans infection, blockade of Dectin-2 did not affect innate immune resistance but abrogated Candida-specific T cell production of IL-17 and, in combination with the absence of Dectin-1, decreased Th1 responses to the organism. Thus, Dectin-2 constitutes a major fungal PRR that can couple to the Syk–CARD9 innate signaling pathway to activate DCs and regulate adaptive immune responses to fungal infection.

Pattern recognition receptor-mediated innate immune responses in seminal vesicle epithelial cell and their impacts on cellular function†

2019 ◽  
Vol 101 (4) ◽  
pp. 733-747 ◽  
Author(s):  
Maolei Gong ◽  
Fei Wang ◽  
Weihua Liu ◽  
Ran Chen ◽  
Han Wu ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Epithelial Cells ◽  
Immune Responses ◽  
Pattern Recognition Receptors ◽  
Seminal Vesicles ◽  
Pattern Recognition Receptor ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Toll Like Receptor ◽  
Recognition Receptor

Abstract The seminal vesicles can be infected by microorganisms, thereby resulting in vesiculitis and impairment in male fertility. Innate immune responses in seminal vesicles cells to microbial infections, which facilitate vesiculitis, have yet to be investigated. The present study aims to elucidate pattern recognition receptor–mediated innate immune responses in seminal vesicles epithelial cells. Various pattern recognition receptors, including Toll-like receptor 3, Toll-like receptor 4, cytosolic ribonucleic acid, and deoxyribonucleic acid sensors, are abundantly expressed in seminal vesicles epithelial cells. These pattern recognition receptors can recognize their respective ligands, thus activating nuclear factor kappa B and interferon regulatory factor 3. The pattern recognition receptor signaling induces expression of pro-inflammatory cytokines, such as tumor necrosis factor alpha (Tnfa) and interleukin 6 (Il6), chemokines monocyte chemoattractant protein-1 (Mcp1) and C–X–C motif chemokine 10 (Cxcl10), and type 1 interferons Ifna and Ifnb. Moreover, pattern recognition receptor-mediated innate immune responses up-regulated the expression of microsomal prostaglandin E synthase and cyclooxygenase 2, but they down-regulated semenogelin-1 expression. These results provide novel insights into the mechanism underlying vesiculitis and its impact on the functions of the seminal vesicles.

PRRs in pathogen recognition

2006 ◽  
Vol 1 (3) ◽  
pp. 299-313 ◽  
Author(s):  
Satoshi Uematsu ◽  
Shizuo Akira
Keyword(s):  
Pattern Recognition ◽  
Immune Responses ◽  
Pattern Recognition Receptors ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Pathogen Recognition ◽  
First Line ◽  
Adaptive Immune Responses ◽  
Adaptive Immune ◽  
Wide Range

AbstractThe innate immune system provides the first line of host defense against invading microorganisms before the development of adaptive immune responses. Innate immune responses are initiated by germline-encoded pattern recognition receptors (PRRs), which recognize specific structures of microorganisms. Toll-like receptors (TLRs) are pattern-recognition receptors that sense a wide range of microorganisms, including bacteria, fungi, protozoa and viruses. TLRs exist either on the cell surface or in the lysosome/endosome compartment and induce innate immune responses. Recently, cytoplasmic PRRs have been identified which detect pathogens that have invaded the cytosol. This review focuses on the pathogen recognition of PRRs in innate immunity.

scholarly journals Structural aspects of molecular recognition in the immune system. Part II: Pattern recognition receptors (IUPAC Technical Report)

2014 ◽  
Vol 86 (10) ◽  
pp. 1483-1538 ◽  
Author(s):  
John A. Robinson ◽  
Kerstin Moehle
Keyword(s):  
Pattern Recognition ◽  
Immune System ◽  
Immune Responses ◽  
Signaling Pathways ◽  
Innate Immune System ◽  
Pattern Recognition Receptors ◽  
Innate Immune ◽  
Helicase Domain ◽  
Downstream Signaling ◽  
Adaptive Immune

Abstract The vertebrate immune system uses pattern recognition receptors (PRRs) to detect a large variety of molecular signatures (pathogen-associated molecular patterns, PAMPs) from a broad range of different invading pathogens. The PAMPs range in size from relatively small molecules, to others of intermediate size such as bacterial lipopolysaccharide, lipopeptides, and oligosaccharides, to macromolecules such as viral DNA, RNA, and pathogen-derived proteins such as flagellin. Underlying this functional diversity of PRRs is a surprisingly small number of structurally distinct protein folds that include leucine-rich repeats in Toll-like receptors (TLRs) and NOD-like receptors (NLRs), the DExH box helicase domain in RIG-like receptors (RLRs), and C-type lectin domains (CTLDs) in the C-type lectins. Following PAMP recognition by the PRRs, downstream signaling pathways activate the innate immune system to respond to invading pathogenic organisms. The resulting stimulatory response is also vital for a balanced adaptive immune response to the pathogen, mediated by circulating antibodies and/or cytotoxic T cells. However, an aberrant stimulation of the innate immune system can also lead to excessive inflammatory and toxic stress responses. Exciting opportunities are now arising for the design of small synthetic molecules that bind to PRRs and influence downstream signaling pathways. Such molecules can be useful tools to modulate immune responses, for example, as adjuvants to stimulate adaptive immune responses to a vaccine, or as therapeutic agents to dampen aberrant immune responses, such as inflammation. The design of agonists or antagonists of PRRs can now benefit from a surge in knowledge of the 3D structures of PRRs, many in complexes with their natural ligands. This review article describes recent progress in structural studies of PRRs (TLRs, NLRs, CTLs, and RLRs), which is required for an understanding of how they specifically recognize structurally diverse “foreign” PAMPs amongst a background of other “self” molecules, sometimes closely related in structure, that are present in the human body.

scholarly journals Influence of Galectin-3 on the Innate Immune Response during Experimental Cryptococcosis

2021 ◽  
Vol 7 (6) ◽  
pp. 492
Author(s):  
Caroline Patini Rezende ◽  
Patricia Kellen Martins Oliveira Brito ◽  
Thiago Aparecido Da Silva ◽  
Andre Moreira Pessoni ◽  
Leandra Naira Zambelli Ramalho ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Immune Responses ◽  
Profile Analysis ◽  
Innate Immune ◽  
Gene Profile ◽  
Adaptive Immune ◽  
Galectin 3 ◽  
Experimental Cryptococcosis ◽  
Antifungal Immunity ◽  
Recognition Receptor

Cryptococcus neoformans, the causative agent of cryptococcosis, is the primary fungal pathogen that affects the immunocompromised individuals. Galectin-3 (Gal-3) is an animal lectin involved in both innate and adaptive immune responses. The present study aimed to evaluate the influence of Gal-3 on the C. neoformans infection. We performed histopathological and gene profile analysis of the innate antifungal immunity markers in the lungs, spleen, and brain of the wild-type (WT) and Gal-3 knockout (KO) mice during cryptococcosis. These findings suggest that Gal-3 absence does not cause significant histopathological alterations in the analyzed tissues. The expression profile of the genes related to innate antifungal immunity showed that the presence of cryptococcosis in the WT and Gal-3 KO animals, compared to their respective controls, promoted the upregulation of the pattern recognition receptor (PRR) responsive to mannose/chitin (mrc1) and a gene involved in inflammation (ccr5), as well as the downregulation of the genes related to signal transduction (card9, fos, ikbkb, jun) and PRRs (cd209a, colec12, nptx1). The absence of Gal-3, in fungal infection, a positively modulated gene involved in phagocytosis (sftpd) and negatively genes involved in signal transduction (syk and myd88), proinflammatory cytokines il-1β and il-12b and cd209a receptor. Therefore, our results suggest that Gal-3 may play an essential role in the development of antifungal immune responses against cryptococcosis.

Pattern Recognition Receptor-initiated Innate Immune Responses in mouse Prostatic Epithelial Cells

2021 ◽  
Author(s):  
Xiaoqin Yu ◽  
Ran Chen ◽  
Fei Wang ◽  
Weihua Liu ◽  
Wenjing Zhang ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Epithelial Cells ◽  
Immune Responses ◽  
Pattern Recognition Receptor ◽  
Innate Immune ◽  
Poly I:C ◽  
Innate Immune Responses ◽  
Local Inflammation ◽  
Recognition Receptor

Abstract Three major pathogenic states of the prostate, including benign prostatic hyperplasia, prostate cancer, and prostatitis, are related to the local inflammation. However, the mechanisms underlying the initiation of prostate inflammation remain largely unknown. Given that the innate immune responses of the tissue-specific cells to microbial infection or auto-antigens contribute to local inflammation, this study focused on pattern recognition receptor (PRR)-initiated innate immune responses in mouse prostatic epithelial cells (PECs). Primary mouse PECs abundantly expressed Toll-like receptor 3 (TLR3), TLR4, TLR5, melanoma differentiation-associated protein 5 (MDA5) and p204. These PRRs can be activated by their respective ligands: lipopolysaccharide (LPS) and flagellin of Gram-negative bacteria for TLR4 and TLR5, polyinosinic-polycytidylic acid (poly(I:C)) for TLR3 and MDA5, and herpes simplex virus DNA analog (HSV60) for p204. LPS and flagellin predominantly induced the expression of inflammatory cytokines, including TNFA, IL6, MCP1, and CXCL10. Poly(I:C) and HSV60 predominantly induced the expression of type 1 interferons (IFNA and IFNB) and antiviral proteins: Mx GTPase 1, 2′,5′-oligoadenylate synthetase 1, and IFN-stimulated gene 15. The replication of mumps virus in PECs was inhibited by type 1 IFN signaling. These findings provide insights into the mechanisms underlying innate immune response in the prostate.

scholarly journals CARD9 mediates Dectin-1–induced ERK activation by linking Ras-GRF1 to H-Ras for antifungal immunity

2014 ◽  
Vol 211 (11) ◽  
pp. 2307-2321 ◽  
Author(s):  
Xin-Ming Jia ◽  
Bing Tang ◽  
Le-Le Zhu ◽  
Yan-Hui Liu ◽  
Xue-Qiang Zhao ◽  
...  
Keyword(s):  
Immune Responses ◽  
Fungal Infection ◽  
Inhibitory Effect ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Erk Activation ◽  
Ras Activation ◽  
Extracellular Signal ◽  
Proinflammatory Responses ◽  
Recognition Receptor

Dectin-1 functions as a pattern recognition receptor for sensing fungal infection. It has been well-established that Dectin-1 induces innate immune responses through caspase recruitment domain-containing protein 9 (CARD9)–mediated NF-κB activation. In this study, we find that CARD9 is dispensable for NF-κB activation induced by Dectin-1 ligands, such as curdlan or Candida albicans yeast. In contrast, we find that CARD9 regulates H-Ras activation by linking Ras-GRF1 to H-Ras, which mediates Dectin-1–induced extracellular signal-regulated protein kinase (ERK) activation and proinflammatory responses when stimulated by their ligands. Mechanistically, Dectin-1 engagement initiates spleen tyrosine kinase (Syk)–dependent Ras-GRF1 phosphorylation, and the phosphorylated Ras-GRF1 recruits and activates H-Ras through forming a complex with CARD9, which leads to activation of ERK downstream. Finally, we show that inhibiting ERK activation significantly accelerates the death of C. albicans–infected mice, and this inhibitory effect is dependent on CARD9. Together, our studies reveal a molecular mechanism by which Dectin-1 induces H-Ras activation that leads to ERK activation for host innate immune responses against fungal infection.

Sign in / Sign up

Export Citation Format

Share Document