cGAS/STING通路的生物学功能及其在细菌感染中的作用北大核心

先天免疫是宿主抵御外来病原体入侵的第一道防线,而模式识别受体(pattern recognition receptors,PRRs)是介导先天免疫应答关键分子。PRRs通过识别病原体相关分子模式(pathogen associated molecular patterns,PAMPs)来激活宿主先天免疫反应。二十一世纪先天免疫领域里程碑式发现-环磷酸鸟苷腺苷合成酶(cyclic GMP-AMP synthase,cGAS),cGAS在宿主先天免疫过程中发挥重要作用,通过识别外源DNA产生第二信使2’,3’-环化鸟苷酸腺苷酸(2’,3’-cyclic guanosine monophosphate adenosine monophosphate,2’,3’-cGAMP)来介导干扰素基因刺激因子(stimulator of interferon genes,STING)的活化,从而促进下游干扰素(IFN)和其他细胞因子分泌来发挥宿主的抗病毒反应。近年研究发现,cGAS/STING通路在宿主抗细菌感染过程中发挥着重要作用,同时细菌也进化出不同机制来拮抗cGAS/STING通路。本文主要对cGAS/STING通路的生物学功能及其在细菌感染中的作用进行综述,为进一步研发新型抗菌药物提供理论参考。     

Cancer cell-specific cGAS/STING Signaling pathway in the era of advancing cancer cell biology

Pattern-recognition receptors (PRRs) are critical to recognizing endogenous and exogenous threats to mount a protective proinflammatory innate immune response. PRRs may be located on the outer cell membrane, cytosol, and nucleus. The cGAS/STING signaling pathway is a cytosolic PRR system. Notably, cGAS is also present in the nucleus. The cGAS-mediated recognition of cytosolic dsDNA and its cleavage into cGAMP activates STING. Furthermore, STING activation through its downstream signaling triggers different interferon-stimulating genes (ISGs), initiating the release of type 1 interferons (IFNs) and NF-κB-mediated release of proinflammatory cytokines and molecules. Activating cGAS/STING generates type 1 IFN, which may prevent cellular transformation and cancer development, growth, and metastasis. The current article delineates the impact of the cancer cell-specific cGAS/STING signaling pathway alteration in tumors and its impact on tumor growth and metastasis. This article further discusses different approaches to specifically target cGAS/STING signaling in cancer cells to inhibit tumor growth and metastasis in conjunction with existing anticancer therapies.     

宫颈癌患者人乳头瘤病毒感染情况及STING、ZEB1蛋白水平分析

分析宫颈癌患者人乳头瘤病毒（HPV）感染情况及癌灶组织内干扰素基因刺激因子（STING）、E盒锌指结合蛋白1（ZEB1）表达情况,为该类患者的治疗提供参考。

收集我院病理检验科2019年1月至2022年1月63例宫颈癌标本（宫颈癌组）、55例宫颈上皮内瘤变（CIN）标本（CIN组）及50例正常宫颈标本（正常组）,采用免疫组化法检测各标本内STING及ZEB1表达情况,采用原位杂交法检测各标本内高危HPV感染情况,分析STING及ZEB1蛋白表达情况与宫颈癌病理特征及高危HPV感染之间的关系。

宫颈癌组标本STING及ZEB1表达量均高于CIN组及正常组,CIN组标本ZEB1表达量高于正常组,差异均有统计学意义（均P＜0.05）;CIN组标本STING表达量与正常组比较差异无统计学意义（P＞0.05）。宫颈癌组标本HPV16、18检出率高于CIN组及正常组,CIN组标本HPV16、18检出率高于正常组,差异均有统计学意义（均P＜0.05）。宫颈癌患者FIGO分期及浸润深度与其组织内STING及ZEB1蛋白阳性情况均存在相关性;此外,宫颈癌淋巴结转移及肿瘤分化程度与组织内STING蛋白阳性情况存在相关性,差异均有统计学意义（均P＜0.05）。宫颈癌患者STING及ZEB1蛋白表达与其HPV16、18检出率间均呈正相关（均P＜0.05）。

宫颈癌组标本STING及ZEB1蛋白表达量均高于正常组及CIN组,且其表达量还与宫颈癌浸润、FIGO分期相关。STING和ZEB1可能与HPV16、18感染共同参与宫颈癌的发生及进展。

     

Expression of a human coxsackie/adenovirus receptor transgene permits adenovirus infection of primary lymphocytes

Replication-defective adenoviruses are effective vehicles for gene transfer, both for the repair of defective genes and for studies of gene function in primary cells. Many cell types, including lymphocytes, are refractory to adenovirus infection because they lack the Coxsackie/adenovirus receptor (CAR) needed for virus attachment. To extend the advantages of adenovirus-mediated gene transfer to primary lymphoid populations and other cell types lacking endogenous CAR, we produced a mouse that expresses human (h) CAR as a transgene under control of a murine MHC class I promoter. hCAR protein is expressed on T and B lymphocytes from a variety of organs (spleen, lymph node, bone marrow, thymus, and peritoneum). These lymphocytes are susceptible to adenovirus infection, as demonstrated by reporter green fluorescent protein gene expression, with the fraction of expressing cells as high as 70%. Some lymphocyte subpopulations required stimulation subsequent to adenovirus infection for reporter expression. This activation requirement is a restriction imposed by the promoter used in the adenovirus construct. In subpopulations requiring activation, the elongation factor 1 promoter was far superior to a hCMV promoter for directing green fluorescent protein production. We also find that hCAR mRNA is produced in nonlymphoid tissues from all founder lines, including tissues that do not express endogenous murine CAR, suggesting the opportunity for effecting gene delivery to and testing gene function in a wide variety of primary cell types previously resistant to gene transfer.     

Control of interferon signaling in human papillomavirus infection

Human papillomaviruses (HPV) infect mucosal and cutaneous epithelium resulting in several types of pathologies, most notably, cervical cancer. Persistent infection with sexually transmitted oncogenic HPV types represents the major risk factor for the development of cervical cancer. The development of HPV-associated cervical cancer has been closely linked to the expression of the viral oncogenes E6 and E7 in the tumor cells. The major viral oncoproteins, E6 and E7, target the cellular tumor suppressor gene products p53 and Rb, respectively. As detailed within, these interactions result in the stimulation of proliferation and the inhibition of apoptosis, thus representing major oncogenic insults to the infected cell. In addition to mediating transformation, the E6 and E7 genes also play significant roles in altering the immune response against infected cells by suppressing interferon (IFN) expression and signaling. At the clinical level, IFNs have been used in the treatment of HPV-associated cervical intraepithelial neoplasia (CIN) or cervical cancers with mixed results. The success of the treatment is largely dependent on the subtype of HPV and the immune response of the patients. Despite this inefficiency, the increasing knowledge about the regulation of IFN signaling pathways at molecular level may hold a promise for the use of new therapeutic strategies against HPV infection. Studies on the regulation of the function of IFN-inducible gene products by the E6 and E7 may lead to the development of new therapeutic approaches based on strategies that modify the function of the HPV oncoproteins and restore IFN-signaling pathways through endogenous control mechanisms.     

Sneathia属细菌与宫颈人乳头瘤病毒感染及宫颈病变的关系

高危型人乳头瘤病毒（human papilloma,HPV）的持续感染可导致宫颈癌前病变和宫颈癌。阴道微生物群在HPV感染和宫颈病变的发生中起主要作用。近年来,利用分子生物学测序技术揭示了Sneathia属细菌与HPV感染和宫颈病变密切相关,阴道菌群中Sneathia属细菌的富集可能促进了HPV感染及宫颈病变的发生,作用机制尚不清楚,但可能与破坏宫颈上皮和影响宿主免疫系统有关。Sneathia属细菌可能成为预防和治疗宫颈病变的潜在靶点。

     

Reproducibility of the cytologic diagnosis of human papillomavirus infection

As part of a larger epidemiologic investigation of the association between human papillomavirus (HPV) infection and cervical intraepithelial neoplasia, the reliability of the cytologic diagnosis of HPV infection was examined. A random sample of cervicovaginal specimens with cytologic changes characteristic of HPV infection were matched with a second set of slides, with regard to the date and severity of the smear and the age of the woman from whom the smear was obtained. The kappa statistic for interobserver agreement was 0.38 (p less than 0.0005), increasing to 0.68 (p less than 0.0005) when uncertain diagnoses were excluded. Intraobserver agreement ranged from kappa = 0.40 to 1.00. Although this agreement is within the range of reliability found for the diagnosis of other atypical cytologic changes, considerable variation is present. The effect of this variability on the validity of estimating the risk of cervical cancer associated with HPV infection may be considerable.     

A prospective study of human papillomavirus infection of the cervix

In a prospective study 42 women, diagnosed as having low grade cervical intraepithelial neoplasia (CIN), made a total of 281 clinic visits over a 45 month period. At each visit, they were subjected to cytological and colposcopical examination and samples were taken for human papillomavirus (HPV) DNA hybridization studies and for the detection of non-HPV infections. HPV types 16 and/or 18 were found in 25% of all the samples tested and these virus types were detected in five of six (83%) women whose lesions progressed compared to seven of 14 (50%) of those whose lesions regressed. The presence of HPV DNA was not a good prognostic indicator of progression since half of those whose disease regressed also harboured these viruses at some time. The recording of non-HPV infections almost 10 times more often in the women whose disease regressed than in those whose disease progressed could probably be accounted for by the former having a larger number of follow-up visits. Nevertheless, the significance of non-HPV infections also remains unclear.     

Expression of Cre recombinase during transient phage infection permits efficient marker removal in Streptomyces

We report a system for the efficient removal of a marker flanked by two loxP sites in Streptomyces coelicolor, using a derivative of the temperate phage C31 that expresses Cre recombinase during a transient infection. As the test case for this recombinant phage (called Cre-phage), we present the construction of an in-frame deletion of a gene, pglW, required for phage growth limitation or Pgl in S.coelicolor. Cre-phage was also used for marker deletion in other strains of S.coelicolor.     

Persistence of human papillomavirus infection: keys to malignant progression

Human papillomaviruses (HPVs) are the etiologic agents of cervical and other epithelial cancers. Persistence of infections by high-risk HPV types is the single greatest risk factor for malignant progression. Although prophylactic vaccines have been developed that target high-risk HPV types, there is a continuing need to understand better the virus-host interactions that underlie persistent benign infection and progression to cancer. In this review we summarize the molecular events that facilitate the differentiation-dependent HPV life cycle, how the life cycle is organized to facilitate virus persistence, and how the activities of HPV regulatory proteins result in malignancy.     

1 516例性病门诊患者人乳头瘤病毒感染情况及其基因型别

目的 了解性病门诊患者人乳头瘤病毒（HPV）的感染情况及其基因型别。方法 用导流杂交分型检测法对1 516例性病门诊患者进行HPV检测与基因分型,评价HPV及其基因型别与疾病类型的关系。结果 1 516例受检者中,HPV总阳性率为55.61%。基因型分析发现,26例鲍温病样丘疹病患者均有高危型HPV感染,而762例尖锐湿疣患者中低危型HPV感染占70.86%。21种HPV基因型均被检出,以HPV6（28.86%）、11（17.23%）、16（10.41%）型感染最为常见。检出的843例阳性患者中单一型别感染占61.68%,以HPV6和HPV11感染为主;HPV多重感染以高低危型HPV混合感染为主。结论 HPV基因型别分布与疾病类型密切相关,HPV亚型的鉴别对相关疾病的预防和治疗具有临床应用价值。     

Message in a bottle: lessons learned from antagonism of STING signalling during RNA virus infection

STING has emerged in recent years as an important signalling adaptor in the activation of type I interferon responses during infection with DNA viruses and bacteria. An increasing body of evidence suggests that STING also modulates responses to RNA viruses, though the mechanisms remain less clear. In this review, we give a brief overview of the ways in which STING facilitates sensing of RNA viruses. These include modulation of RIG-I-dependent responses through STING's interaction with MAVS, and more speculative mechanisms involving the DNA sensor cGAS and sensing of membrane remodelling events. We then provide an in-depth literature review to summarise the known mechanisms by which RNA viruses of the families Flaviviridae and Coronaviridae evade sensing through STING. Our own work has shown that the NS2B/3 protease complex of the flavivirus dengue virus binds and cleaves STING, and that an inability to degrade murine STING may contribute to host restriction in this virus. We contrast this to the mechanism employed by the distantly related hepacivirus hepatitis C virus, in which STING is bound and inactivated by the NS4B protein. Finally, we discuss STING antagonism in the coronaviruses SARS coronavirus and human coronavirus NL63, which disrupt K63-linked polyubiquitination and dimerisation of STING (both of which are required for STING-mediated activation of IRF-3) via their papain-like proteases. We draw parallels with less-well characterised mechanisms of STING antagonism in related viruses, and place our current knowledge in the context of species tropism restrictions that potentially affect the emergence of new human pathogens.     

Different modes of human papillomavirus DNA replication during maintenance

Human papillomavirus (HPV) begins its life cycle by infecting the basal cells of the epithelium. Within these proliferating cells, the viral genomes are replicated, maintained, and passed on to the daughter cells. Using HPV episome-containing cell lines that were derived from naturally infected cervical tissues, we investigated the mode by which the viral DNAs replicate in these cells. We observed that, whereas HPV16 DNA replicated in an ordered once-per-S-phase manner in W12 cells, HPV31 DNA replicated via a random-choice mechanism in CIN612 cells. However, when HPV16 and HPV31 DNAs were separately introduced into an alternate keratinocyte cell line NIKS, they both replicated randomly. This indicates that HPV DNA is inherently capable of replicating by either random-choice or once-per-S-phase mechanisms and that the mode of HPV DNA replication is dependent on the cells that harbor the viral episome. High expression of the viral replication protein E1 in W12 cells converted HPV16 DNA replication to random-choice replication and, as such, it appears that the mode of HPV DNA replication in proliferating cells is dependent on the presence or the increased level of this protein in the host cell. The implications of these observations on maintenance, latency, and persistence are discussed.     

Prevalence of human papillomavirus infection among young women in North India

Background: The number of women infected with human papillomavirus (HPV) and the distribution of the HPV genotypes vary across populations and with age. Objective: To determine the prevalence and genotype distribution of HPV in young married women aged 16–24 years. Methods: 1300 women residing in an urban slum in Delhi donated samples of exfoliated cervical cells that were collected by the Digene^® kit and tested for the presence of HPV DNA by two techniques in parallel, i.e., PCR using PGMY consensus primers for all HPV types and the Digene HPV test (Hybrid Capture 2 (HC2) Probe B for high-risk (hr) types. Genotyping was done on all HPV positive samples using the Roche reverse line blot assay. Results: HPV infection was detected in 91/1300 (7%) samples by PCR and 110/1300 (8.4%) samples by HC2. Genotyping identified 20 high-risk and 11 low-risk types. HPV16 was the commonest high-risk type (3%) followed by HPV52 (1.2%) and HPV51 (0.8%). Among low-risk types, HPV62 was the commonest (0.8%), followed by HPV84 and HPV89 (0.5% each). Multiple infections were found in 3% of the HPV positive samples. Conclusion: A wide spectrum of HPV genotypes is seen in this young population. Knowledge about HPV types prevalent in communities in different regions of India would be useful in devising the optimum strategy for cervical cancer prevention.     

Identification of the dynein light chains required for human papillomavirus infection

Human papillomaviruses (HPVs) are a family of small non-enveloped DNA viruses. Some genital HPV types, including HPV type 16 (HPV16), are the causative agent for the development of cancer at the site of infection. HPVs encode two capsid proteins, L1 and L2. After endocytic cell entry and egress from endosomes, L2 accompanies the viral DNA to the nucleus where replication is initiated. For cytoplasmic transport, L2 interacts with the microtubule network via the motor protein complex dynein. We have performed yeast two-hybrid screening and identified the dynein light chain DYNLT1 (previously called Tctex1) as interaction partner of HPV16 L2. Using co-immunoprecipitation and immunofluorescence colocalization studies we confirmed the L2-DYNLT1 interaction in mammalian cells. Further studies revealed that DYNLT3, the second member of the Tctex-light chain family, also interacts with L2 in vitro and in vivo, whereas other constituents of the dynein complex were not found to associate with L2. Depletion of DYNLT1 and DYNLT3 by specific siRNAs or cytosolic delivery of light chain-specific antibodies inhibited infection of HPV16. Therefore, this work identified two host cell proteins involved in HPV16 infection that are most likely required for transport purposes towards the nucleus.     

人乳头状瘤病毒感染与肺癌关系的研究进展

近年越来越多的研究发现肺癌组织中有人乳头状瘤病毒（human papillomavirus,HPV）DNA和癌蛋白的检出,其检出率具有地域差异性,但不同地方HPV检出亚型具有高度的一致性,主要是高危型HPV-16和HPV-18。HPV可能主要通过血液循环从宫颈癌病灶等原发部位转移到肺,从而可能诱发肺癌的发生。HPV诱发肺癌的机制可能与影响p53的失活及端粒酶的激活等有关。     

Vesicular trafficking through cortical actin during exocytosis is regulated by the Rab27a effector JFC1/Slp1 and the RhoA-GTPase-activating protein Gem-interacting protein

Cytoskeleton remodeling is important for the regulation of vesicular transport associated with exocytosis, but a direct association between granular secretory proteins and actin-remodeling molecules has not been shown, and this mechanism remains obscure. Using a proteomic approach, we identified the RhoA-GTPase-activating protein Gem-interacting protein (GMIP) as a factor that associates with the Rab27a effector JFC1 and modulates vesicular transport and exocytosis. GMIP down-regulation induced RhoA activation and actin polymerization. Importantly, GMIP-down-regulated cells showed impaired vesicular transport and exocytosis, while inhibition of the RhoA-signaling pathway induced actin depolymerization and facilitated exocytosis. We show that RhoA activity polarizes around JFC1-containing secretory granules, suggesting that it may control directionality of granule movement. Using quantitative live-cell microscopy, we show that JFC1-containing secretory organelles move in areas near the plasma membrane deprived of polymerized actin and that dynamic vesicles maintain an actin-free environment in their surroundings. Supporting a role for JFC1 in RhoA inactivation and actin remodeling during exocytosis, JFC1 knockout neutrophils showed increased RhoA activity, and azurophilic granules were unable to traverse cortical actin in cells lacking JFC1. We propose that during exocytosis, actin depolymerization commences near the secretory organelle, not the plasma membrane, and that secretory granules use a JFC1- and GMIP-dependent molecular mechanism to traverse cortical actin.