Research progress on the role of STING signal pathway in ischemia-reperfusion injury / 器官移植

Ischemia-reperfusion injury (IRI) is a pathophysiological process, which widely exists in organ transplantation and surgery. IRI is mainly manifested with hypoxia injury of organs or tissues during the ischemia period, which could be further aggravated after reperfusion. Ischemia-reperfusion induces tissue cell injury, releases damage-associated molecular pattern and further activates multiple immune cells via pattern recognition receptor, leading to aseptic inflammation and aggravating tissue injury. Cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS), as a critical member of pattern recognition receptor, could activate the stimulator of interferon genes (STING) signal pathway and play an important regulatory role in innate immune response. At present, increasing evidences have shown that cGAS-STING signal pathway plays a significant role in organ IRI. In this article, STING signaling pathway, its role and mechanism in IRI of different organs were reviewed, aiming to provide novel ideas for clinical interventions.

Role of NLRP3 inflammasome and related inflammatory signaling pathways in renal ischemia-reperfusion injury / 器官移植

Renal ischemia-reperfusion injury (IRI) commonly occurs in renal transplantation, which is an important pathophysiological process that causes acute renal failure and severely affects clinical prognosis of the recipients. Inflammatory response plays a critical role in the pathogenesis and pathological process of IRI. Activated NOD-like receptor protein 3(NLRP3) inflammasome can mediate the maturation and release of various pro-inflammatory cytokines, thereby regulating the inflammatory response and relevant cell functions. In this article, the mechanism underlying NLRP3 inflammasome and its related inflammatory signaling pathway in renal IRI were reviewed, aiming to provide novel ideas for clinical prevention and treatment of renal IRI.

Roles of pattern recognition receptors in diabetic nephropathy / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Diabetic nephropathy (DN) is currently the most common complication of diabetes. It is considered to be one of the leading causes of end-stage renal disease (ESRD) and affects many diabetic patients. The pathogenesis of DN is extremely complex and has not yet been clarified; however, in recent years, increasing evidence has shown the important role of innate immunity in DN pathogenesis. Pattern recognition receptors (PRRs) are important components of the innate immune system and have a significant impact on the occurrence and development of DN. In this review, we classify PRRs into secretory, endocytic, and signal transduction PRRs according to the relationship between the PRRs and subcellular compartments. PRRs can recognize related pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), thus triggering a series of inflammatory responses, promoting renal fibrosis, and finally causing renal impairment. In this review, we describe the proposed role of each type of PRRs in the development and progression of DN.

Roles of pattern recognition receptors in diabetic nephropathy / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Diabetic nephropathy (DN) is currently the most common complication of diabetes. It is considered to be one of the leading causes of end-stage renal disease (ESRD) and affects many diabetic patients. The pathogenesis of DN is extremely complex and has not yet been clarified; however, in recent years, increasing evidence has shown the important role of innate immunity in DN pathogenesis. Pattern recognition receptors (PRRs) are important components of the innate immune system and have a significant impact on the occurrence and development of DN. In this review, we classify PRRs into secretory, endocytic, and signal transduction PRRs according to the relationship between the PRRs and subcellular compartments. PRRs can recognize related pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), thus triggering a series of inflammatory responses, promoting renal fibrosis, and finally causing renal impairment. In this review, we describe the proposed role of each type of PRRs in the development and progression of DN.

Expression of genes associated with pattern recognition receptors in peripheral blood mononuclear cells from patients with dengue fever / 中华微生物学和免疫学杂志

Objective@#To investigate the roles of pattern recognition receptors (PRRs) including Toll-like receptors (TLRs), retinoic acid-inducible geneⅠ-like receptors (RLRs) and nucleotide binding oligomerization domain-like receptors (NLRs) in the pathogenesis of dengue fever (DF) and the induction of immune responses to dengue virus.@*Methods@#Blood samples were collected from patients with DF at three different time points to isolate peripheral blood mononuclear cells (PBMCs) by density gradient centrifugation. Then PBMCs were used to extract ribonucleic acid (RNA). Expression of genes was detected by polymerase chain reaction (PCR) array.@*Results@#Expression of genes relating to PRRs signaling pathways in DF patients increased significantly in the early stage of the disease as compared with those in healthy controls, but decreased gradually during the recovery period. Expression of genes encoding TLR7 and TLR8 was enhanced at the early stage of DF. No significant changes in the expression of TLR3 and TLR9 genes were observed during the course of the disease. The genes encoding RIG-Ⅰ, MDA5 and LGP2 of RLRs family as well as NOD2 and OAS2 of NLRs family were all up-regulated.@*Conclusion@#Signaling pathways mediated by PRRs including TLR7/8, RIG-Ⅰ, MDA5 and so on play an important role in the pathogenesis of DF and the induction of immune responses to dengue virus.

Research progress in innate immune mechanisms during influenza A virus infection / 中华实验和临床病毒学杂志

Influenza A virus is an enveloped virus of the Orthomyxoviridae family. Acute fever, generalized pain, fatigue and respiratory symptoms are the typical symptoms after influenza A virus infection. Influenza A virus triggers the activation of signaling pathways that are dependent on host pattern recognition receptors (PRRs) including toll-like receptors (TLRs), retinoic acid-inducible gene I receptors (RLRs) and NLRs. Then these signaling pathways activate downstream transcript factors that induce expression of various interferons and cytokines (IL-1, IL-18). This review will elaborate the mechanisms of these PRRs.

Expression of CD14 and toll-like receptors 2 and 4 by milk neutrophils in bovine mammary glands infected with Corynebacterium bovis / Expressão de CD14 e dos receptores do tipo toll 2 e 4 por neutrófilos lácteos provenientes de glândulas infectadas por Corynebacterium bovis

This study evaluated the expression of CD14, toll-like receptor (TLR) 2 and TLR4 on the surface of milk neutrophils in bovine mammary glands infected with Corynebacterium bovis. Here, we used 23 culture-negative control quarters with no abnormal secretion on the strip cup test and milk somatic cell count lower than 1x105 cells/mL, and 14 C. bovis infected quarters. The identification of neutrophils, as well as, the percentage of neutrophils that expressed CD14, TLR2 and TLR4 were analyzed by flow cytometry using monoclonal antibodies. The present study encountered no significant difference in the percentages of milk neutrophils that expressed TLR2 and TLR4 or in the expression of TLR4 by milk neutrophils. Conversely, a lower median fluorescence intensity of TLR2 in milk neutrophils was observed in C. bovis-infected quarters. The percentage of neutrophils that expressed CD14 and the median fluorescence intensity of CD14 in milk neutrophils was also lower in C. bovis-infected quarters...

O presente estudo objetivou avaliar alterações na expressão de CD14, e dos receptores do tipo toll (TLR) 2 e 4 na superfície de neutrófilos lácteos provenientes de glândulas mamárias infectadas por Corynebacterium bovis. O presente estudo utilizou 23 quartos negativos no exame bacteriológico, sem alterações na prova de fundo escuro e com contagem automática de células somáticas menor que 1 x105 células/mL, e 14 quartos mamários infectados por C. bovis A identificação de neutrófilos, assim como a porcentagem de neutrófilos lácteos que expressaram CD14, TLR2 e 4 foram avaliadas por citometria de fluxo utilizando anticorpos monoclonais. A porcentagem de neutrófilos que expressaram TLR2 e TLR4 nos quartos mamários infectados por C. bovis não diferiu dos quartos mamários sadios, assim como na expressão de TLR4. No entanto, a intensidade de fluorescência do TLR2 na superfície dos neutrófilos foi menor nos quartos mamários infectados por C. bovis. A porcentagem de neutrófilos que expressaram CD14 e a intensidade de fluorescência da molécula de CD14 foi menor na superfície dos neutrófilos lácteos dos quartos infectados por C. bovis...

Construction and identification of a recombinant adenoviral vector expressing murine dendritic cell-associ-atedC-type lectin-1 / 医学研究生学报

Objective Dendritic cell-associatedC-type lectin-1 ( Dectin-1) is one of the most important receptors in antifungal innate immune response.This study was to construct a recombinant adenovirus vector expressing themurine Dectin-1gene and acquire a high-concentration adenovirus by amplification and purification. Methods The PCR amplification product CLEC7A-pIRES2-EGFP was cloned into the intermediate vector pDONR221, and then recom-bined with the backbone vector pAD/CMV/V5-DEST to produce a re-combinant plasmid pAD-CLEC7A-pIRE2S -EGFP.The recombinant plasmid was linearized with Pac I and transfected into human embryon-ic kidney ( HEK293) cells to produce recombinant adenovirus pAD-CLEC7Ap-IRES 2-EGFP. The adenovirus was propagated in the HEK293 cells and purified by filtering through the cellulose acetate membrane and concentrating column.Fluorescence microscopy and re-al-time PCR were used to determine the expression of the Dectin-1 gene. Results PCR identification, enzyme digestion, and sequen-cing results manifested theDectin-1 gene in the vector, with the final adenovirus titer of 5×1011 IU/mL.Fluorescence microscopy revealed green fluorescence and real-time PCR assay confirmed that the expression of Dectin-1 was improved by 8677.25 times. Conclusion A relatively high-titer adenovirus expressing Dectin-1 was acquired,which may help to further study the high expression of Dectin-1 in anti-fungal innate immunity in vitro and in vivo.

The in vivo and in vitro Roles of Epithelial Pattern Recognition Receptors in Pneumococcal Infections

Streptococcus pneumoniae, also called pneumococcus, is a major cause of infectious disease in human. Pneumococcus resides in the nasopharynx as an upper respiratory commensal, and most of pneumococcal colonizations are asymptomatic in immunocompetent individuals. When nasopharyngeal mucosal homeostasis is disrupted, pneumococcus migrates into middle ear and lower respiratory tract and causes detrimental colonization. In this regard, the epithelial cells of middle ear and lung act as first line of defense against pneumococcus to prevent invasive pneumococcal diseases. Respiratory epithelial cells express various cell-surface and intra-cellular receptors sensing microbial pathogens and respond to sensed pathogens by triggering intra-cellular signaling pathways and inducing pathogen-specific innate immune responses. Various epithelial cell-surface and intra-cellular receptors, such as Toll-like receptors (TLRs), Nod-like receptors (NLRs), intracellular DNA sensing receptors, and scavenger receptors (SRs), participate in sensing of pneumococcus, and the activation of these receptors by pneumococcal components induces anti-pneumococcal innate immune responses including epithelial apoptosis and inflammatory cytokine/chemokine expressions. Epithelial sensing of pneumococcus is a critical step for setting an early defense against pneumococcal infection, and also is required to recruit and activate innate immune cells and trigger adaptive immunity.

Expression of pattern recognition receptor in patients of EV71 infection / 中华微生物学和免疫学杂志

Objective To investigate the expression of pattern recognition receptor (PRR)of immune cells from the patients with enterovirus 71 ( EV 71 ) infection and the changes of cytokines. Methods Seventy-one patients and 20 age-matched healthy children were enrolled in the study. The patients were divided into three groups according to the critical degree: 20 mild patients, 25 severe patients and 26 critical patients. Real-time PCR were used to evaluate the levels of retinoic acidinducible gene Ⅰ ( RIG- Ⅰ ), melanoma differentitation-associated gene 5 ( MDA5 ) and cytokines IL-12, IFN-α mRNA expression in peripheral blood mononuclear cells (PBMC). The proportions of Toll like receptors(TLRs) on monocytes/macrophages (MC) , myloiddentritic cells (mDC) and plasmacytoiddentritic cells (pDC) were analyzed by flow cytometry. The concentrations of plasma cytokines( IL-12, IFN-α) were measured by ELISA. Results ( 1 ) The proportion of TLR7 is the unique TLR which is increased in mild patients and it was significantly elevated in MC, mDC and pDC in severe group (P＜0.05), TLR2, TLR3 and TLR4 also had an enhanced expression in MC and mDC. The enhanced expression of TLRs mentioned above had a decreased trend in critical patients. (2)Transcription levels of RIG- Ⅰ and MDA5 was significantly elevated in EV71 infected children.(3)The expression levels of DC-associated cytokines gene( IL-12 and IFN-α) have an increased trend in mild cases and these cytokines were remarkably increased in severe patients (P＜0.05), whereas decreased in critical cases (P＜0.05). ConclusionTLR7 might be the main PRR recognizing EV71 in immune cells and RIG-Ⅰ/MDA5 might also take part in the recognition of EV71. The exogenous or endogenous ligands released from bacterial infection and cell destruction could result in the activation of TLR2 or TLR4, inducing the inflammatory response.

Intrinsic and Extrinsic Regulation of Innate Immune Receptors

Pattern recognition receptors (PRRs) in innate immune cells play a pivotal role in the first line of host defense system. PRRs recognize pathogen-associated molecular patterns (PAMPs) or danger-associated molecular patterns (DAMPs) to initiate and regulate innate and adaptive immune responses. PRRs include Toll-like receptors (TLRs), RIG-I-like receptors (RLRs) and NOD-like receptors (NLRs), which have their own features in ligand recognition and cellular location. Activated PRRs deliver signals to adaptor molecules (MyD88, TRIF, MAL/TIRAP, TRAM, IPS-1) which act as important messengers to activate downstream kinases (IKK complex, MAPKs, TBK1, RIP-1) and transcription factors (NF-kappaB, AP-1, IRF3), which produce effecter molecules including cytokines, chemokines, inflammatory enzymes, and type I interferones. Since excessive PRR activation is closely linked to the development of chronic inflammatory diseases, the role of intrinsic and extrinsic regulators in the prevention of over- or unnecessary activation of PRRs has been widely studied. Intracellular regulators include MyD88s, SOCS1, TOLLIP, A20, and CYLD. Extrinsic regulators have also been identified with their molecular targets in PRR signaling pathways. TLR dimerization has been suggested as an inhibitory target for small molecules such as curcumin, cinnamaldehyde, and sulforaphane. TBK1 kinase can be a target for certain flavonoids such as EGCG, luteolin, quercetin, chrysin, and eriodictyol to regulate TRIF-dependent TLR pathways. This review focuses on the features of PRR signaling pathways and the therapeutic targets of intrinsic and extrinsic regulators in order to provide beneficial strategies for controlling the activity of PRRs and the related inflammatory diseases and immune disorders.