Progress in DNA-sensing pathways in Epstein-Barr virus infection / 中华微生物学和免疫学杂志

Epstein-Barr virus (EBV) is generally susceptible in human beings and multi-organ systems can be involved in EBV infection, such as blood, respiratory, urinary, digestive and nervous systems. EBV infection also plays an important role in the pathogenesis of related tumors, autoimmune diseases and other diseases, posing a great threat to human health. As a DNA virus, EBV can be sensed by DNA recognition receptors to trigger a series of downstream immune responses. A DNA-sensing pathway consists of DNA sensors, adaptor molecules and downstream effector signals. Double-stranded DNA sensors mainly include absent in melanoma 2-like receptors (ALRs) and cyclic GMP-AMP synthase (cGAS). Adaptors were mainly stimulator of interferon genes (STING) and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC). Downstream immune responses mainly involve typeⅠIFN, inflammasomes and proinflammatory cytokines. As a double-stranded DNA virus of the Herpesviridae family, EBV triggers complex innate and adaptive immune responses in the host, especially the sensing pathways mediated by a variety of DNA recognition receptors, which play a key role in host immune defense and pathogen immune evasion. This review made the DNA sensor as the clue to comprehensively summarize the progress in the activation, regulatory mechanism and clinical relevance of DNA-sensing pathways in EBV infection in recent years, aiming to achieve a better understanding of the host innate immune responses during EBV infection and provide an immunological basis for the prevention and treatment of EBV infection-related diseases.

Research progress on the mechanisms of inflammasomes during respiratory infections / 中华实用儿科临床杂志

Acute respiratory infections are the most common infectious diseases in children.Among them, respiratory viruses are the main pathogens that cause many respiratory diseases, system damages or even death.As the first line of defense against pathogens like respiratory viruses, the innate immune system recognizes the structural components of viruses and endogenous danger signals with the pattern recognition receptors on immune cells and epithelial cells.During this process, inflammasomes are assembled and activated, and they participate in the recognition of viruses, inflammatory and immune response against viruses.The present study aims to describe the composition and function of inflammasomes, as well as the activation and negative regulation mechanisms of inflammasomes during common respiratory infections.

AIM2 inflammasome activation may mediate high mobility group box 1 release in murine allergic rhinitis / Ativação do inflamassoma AIM2 pode mediar a liberação da proteína do grupo Box-1 de alta mobilidade no modelo murino de rinite alérgica

Abstract Introduction: High mobility group box 1 protein participates in the pathogenesis of allergic rhinitis. Activation of the inflammasome can mediate the release of high mobility group box 1. The role of the absent in melanoma 2 inflammasome in allergic rhinitis remains unclear. Objective: This study aimed to investigate the function of absent in melanoma 2 inflammasome in murine allergic rhinitis and the interaction between high mobility group box 1 and the absent in melanoma 2 inflammasome. Methods: A murine allergic rhinitis model was established using twenty Balb/c mice. Expression of the components of the absent in melanoma 2 inflammasome: absent in melanoma 2, apoptosis-associated speck-like protein containing a CARD (Asc), caspase-1 p20, and additional nod-like receptor family pyrin domain containing 3 (Nlrp3) were detected by western blotting during allergic rhinitis. Alterations of absent in melanoma 2, caspase-1, and high mobility group box 1 after ovalbumin challenge were demonstrated by immunohistochemistry. TdT-mediated dUTP Nick end labeling, TUNEL assay, and cleavage of caspase-3 and PARP-1 were used for the observation of pyroptosis. Results: Eosinophilia and goblet cell infiltration were observed in the nasal mucosa of mice in the allergic rhinitis group. Absent in melanoma 2, Asc, and caspase-1 p20 increased after ovalbumin exposure while Nlrp3 did not. High mobility group box 1 was released in the nasal mucosa of allergic rhinitis mice. TUNEL-positive cells increased in the epithelium and laminae propria, whereas cleavage of caspase-3 and PARP-1 was not observed. Conclusions: The absent in melanoma 2 inflammasome was activated and pyroptosis may occur in the nasal mucosa after ovalbumin treatment. These may contribute to the translocation of high mobility group box 1 and the development of allergic rhinitis.

Resumo Introdução: A proteína do grupo Box-1 de alta mobilidade participa da patogênese da rinite alérgica. A ativação do inflamassoma pode mediar a liberação de proteína do grupo Box-1 de alta mobilidade. O papel do inflamassoma ausente no melanoma 2 na rinite alérgica permanece incerto. Objetivo: Investigar a função do inflamassoma ausente no melanoma 2 em um modelo murino de rinite alérgica e a interação entre a proteína do grupo Box-1 de alta mobilidade e o inflamassoma ausente no melanoma 2. Método: Um modelo murino de rinite alérgica foi estabelecido com 20 camundongos Balb/c. A expressão dos componentes do inflamassoma ausente no melanoma 2, da proteína speck-like associada à apoptose com CARD (Asc), da caspase-1 p20 e do domínio de pirina da família NLR adicional com 3 (Nlrp3) foi detectada por western blotting durante a rinite alérgica. Alterações de inflamassoma ausente no melanoma 2, na caspase-1 e na proteína do grupo Box-1 de alta mobilidade após o teste de provocação com ovalbumina foram demonstradas por imuno-histoquímica. O ensaio dUTP Nick-End Labeling mediado por TdT, TUNEL e clivagem de caspase-3 e PARP-1 foram usados para a observação de piroptose. Resultados: Eosinofilia e infiltração de células caliciformes foram observadas na mucosa nasal de camundongos do grupo rinite alérgica. Inflamassoma ausente no melanoma 2, Asc e caspase-1 p20 aumentou após a exposição à ovalbumina, enquanto Nlrp3 não aumentou. A proteína do grupo Box-1 de alta mobilidade foi liberada na mucosa nasal de camundongos com rinite alérgica. As células TUNEL-positivas aumentaram no epitélio e na lâmina própria, enquanto a clivagem da caspase-3 e a PARP-1 não foram observadas. Conclusão: O inflamassoma ausente no melanoma 2 foi ativado e pode ocorrer piroptose na mucosa nasal após o tratamento com ovalbumina. Esses fatores podem contribuir para a translocação de proteína do grupo Box-1 de alta mobilidade e o desenvolvimento de rinite alérgica.

Lonicerin targets EZH2 to alleviate ulcerative colitis by autophagy-mediated NLRP3 inflammasome inactivation

Aberrant activation of NLRP3 inflammasome in colonic macrophages strongly associates with the occurrence and progression of ulcerative colitis. Although targeting NLRP3 inflammasome has been considered to be a potential therapy, the underlying mechanism through which pathway the intestinal inflammation is modulated remains controversial. By focusing on the flavonoid lonicerin, one of the most abundant constituents existed in a long historical anti-inflammatory and anti-infectious herb

Advances in role of inflammasome in fibrotic diseases / 中国药理学通报

The inflammasome—a molecular complex of proteins whose activation and subsequent secretion of inflammatory cytokines are essential for innate immune defense, playing an significant role in adaptive immune responses. Fibrosis is the final stage of the development of chronic inflammation, which is the result of excessive deposition of extracellular matrix, leading to tissue structure damage and organ dysfunction. This paper reviews the role of inflammasome in fibrotic diseases in order to promote the research and development of inflammasome mechanisms and drugs.

Research progress of AIM2 in tumor / 实用肿瘤学杂志

Absent in melanoma 2(AIM2),as a cytoplasmic DNA sensor,can perceive the cytoplasmic dsDNA which released by the cells infected with DNA virus or bacteria.AIM2 will be raised by Apoptosis-associated speck-like protein containing a CARD to produce inflammation complex,activate of Caspase-1,promote the maturation,and secretion of IL-1β and IL-18,or lead to pyroptosis.AIM2 plays an importation role in initiating immunity.Recent research shows that AIM2 has an influence on the occurrence and progress in tumor,it acts as a tumor suppressor and inhibits tumor progression in liver and breast carcinoma;However,AIM2 shows the carcinogenic effect of promoting tumor development on cervical carcinoma and oral squamous cell carcinoma.These results contribute to the diagnosis and prognosis of malignant tumor.

Cytosolic dsDNA from murine cytomegalovirus can be recognized by AIM2 inflammasome / 中华微生物学和免疫学杂志

ObjectiveTo observe the changes of AIM2 ( absent in melanoma 2) inflammasome during early murine cytomegalovirus (MCMV) infection.MethodsBALB/c mice were randomly divided into two groups.One was infected with MCMV Smith for establishing disseminated infection,the other was sham-inoculated control.On days 1,3,5 and 7 of the experiment,three mice of each group were randomly chosen to be killed separately.The expression of AIM2,ASC and caspase-1 in splenic macrophages was detected by Western blot,the levels of IL-1β and IL-18 in sera were measured by double antibody sandwich ELISA,and the viral titers in salivary gland tissues were quantified by a standard plaque assay.Results The MCMV titers in salivary gland tissues were gradually increased in MCMV-infected mice on days 3,5 and 7,while the expressions of AIM2 in macrophages were began to increase on day 1 and significantly increased and reached the highest level on day 3 but gradually decreased afterwards.The relative intensity of AIM2 on day 3 differed significantly between the MCMV-infected mice and the controls (1.121±0.243 vs 0.240±0.046,P＜0.01,t test),as did ASC ( 1.318±0.333 vs 0.248±0.090,P＜0.01 ) and caspase-1 ( 1.085±0.243 vs 0.247±0.064,P＜0.01 ).Meanwhile,the levels of IL-1β and IL-18 in MCMV-infected mice were (112.72±5.20) pg/ml and (42.74±4.23) pg/ml,and the levels were significantly higher (P＜0.01 ) than those in controls [ (47.86±4.35) pg/ml and (22.60±2.82) pg/ml].ConclusionThese results demonstrate that AIM2 inflammasome is activated in macrophages during early MCMV infection and could be as a therapeutic target for CMV-induced diseases.

Advances in DNA recognition receptors / 中国肿瘤生物治疗杂志

DNA, as the material basis of all living cells, triggers innate immune responses through TLR9 and other cytosolic recognition receptors. In recent years, the research progress of TLR9 is mainly manifested by the following four aspects: (1) the determinants of TLR9 interacting with its ligands; (2) the mechanisms and the importance of TLR9 translocation from the endoplasmic reticulum to the endosome; (3) the roles of the endosomal acidification and maturation, and subsequent TLR9 cleavage in TLR9 signal transduction pathway; and (4) the possible mechanisms by which the organism distinguish self DNA from microbial DNA. Meanwhile, a series of experiments on TLR9 antagonists and TLR9 deficient mice confirmed the presence of TLR9-independent cytosolic DNA sensors. So far, three TLR9-independent DNA sensors have been found, and they are DAI, AIM2, and RNA polymerase Ⅲ.