T3SS

T3SS
  • 文章类型: Journal Article
    活性氧(ROS)在调节生物体的多种功能中起着至关重要的作用。ROS产生的关键调节剂是NADPH氧化酶,主要被称为呼吸爆发氧化酶同系物(RBOHs)。然而,我们对病原体是否以及如何直接靶向RB0Hs的理解受到限制。在这项研究中,我们发现效应蛋白RipBJ,起源于植物病原细菌,存在于低至中毒力菌株中,但不存在于高毒力菌株中。功能性遗传测定表明,ripBJ的表达导致细菌感染的减少。在植物中,RipBJ表达触发了植物细胞死亡和H2O2的积累,同时还通过调节多种防御信号通路来增强宿主对青枯菌的防御。通过蛋白质相互作用和功能研究,我们证明了RipBJ与植物的质膜有关,并与称为SlWfi1的番茄RBOH相互作用,这对RipBJ对植物的影响有积极贡献。重要的是,Solanacearum感染后的早期阶段诱导了SlWfi1表达,并在防御该细菌中起关键作用。这项研究揭示了植物RBOH作为病原体效应物的相互作用靶标,为植物防御机制提供有价值的见解。
    Reactive oxygen species (ROS) play a crucial role in regulating numerous functions in organisms. Among the key regulators of ROS production are NADPH oxidases, primarily referred to as respiratory burst oxidase homologues (RBOHs). However, our understanding of whether and how pathogens directly target RBOHs has been limited. In this study, we revealed that the effector protein RipBJ, originating from the phytopathogenic bacterium Ralstonia solanacearum, was present in low- to medium-virulence strains but absent in high-virulence strains. Functional genetic assays demonstrated that the expression of ripBJ led to a reduction in bacterial infection. In the plant, RipBJ expression triggered plant cell death and the accumulation of H2O2, while also enhancing host defence against R. solanacearum by modulating multiple defence signalling pathways. Through protein interaction and functional studies, we demonstrated that RipBJ was associated with the plant\'s plasma membrane and interacted with the tomato RBOH known as SlWfi1, which contributed positively to RipBJ\'s effects on plants. Importantly, SlWfi1 expression was induced during the early stages following R. solanacearum infection and played a key role in defence against this bacterium. This research uncovers the plant RBOH as an interacting target of a pathogen\'s effector, providing valuable insights into the mechanisms of plant defence.
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  • 文章类型: Journal Article
    提供治疗有效载荷的工程智能微生物正在成为治疗模式,特别是与胃肠道有关的疾病。肠出血性大肠杆菌(EHEC)是潜在致死性溶血性尿毒综合征的病原体。考虑到抗生素治疗会增加大肠杆菌产志贺毒素(Stx),导致全身性疾病的原因,需要新的补救措施。EHEC编码III型分泌系统(T3SS),其将Tir注入肠细胞。Tir插入宿主细胞膜,暴露一个随后结合内膜的胞外域,它的外膜蛋白之一,引发促进EHEC粘膜定植的附着和脱落(A/E)病变的形成。柠檬酸杆菌(Cr),一种天然的A/E小鼠病原体,其发病机制同样需要Tir和intiin。小鼠感染Cr(ΦStx2dact),一种用EHEC衍生的噬菌体溶解的变体,产生Stx2dact,发展肠道A/E病变和毒素依赖性疾病。Stx2a与人类疾病的关系更为密切。通过开发一种有效的方法来无缝地修改啮齿动物的基因组,我们生成了Cr_Tir-MEHEC(ΦStx2a),表达Stx2a和EHEC胞外Tir结构域的变体。我们发现用HS-PROT3EcT-TD4(一种人类共生大肠杆菌菌株(E.coliHS))进行小鼠预定殖,该菌株被设计为有效分泌抗EHECTir纳米抗体,用Cr_Tir-MEHEC(ΦStx2a)攻击后,细菌定植延迟,生存率提高。这项研究提供了第一个证据来支持工程共生大肠杆菌在肠道内递送阻断必需肠道病原体毒力决定因子的治疗性有效载荷的功效,一种可以作为抗生素非依赖性抗菌治疗方式的策略。
    分泌治疗剂的工程智能微生物正在成为治疗方式,特别是肠道疾病。随着多重耐药感染的威胁越来越大,迫切需要非抗生素治疗。胃肠道病原体肠出血性大肠杆菌(EHEC)可引起潜在致死性溶血性尿毒综合征,毒素驱动的疾病.鉴于人们担心抗生素会增加毒素释放,治疗主要限于支持治疗。这里,我们显示,用共生大肠杆菌(HS-PROT3EcT)进行预处理,以分泌阻断必需EHEC毒力因子的抗体,延迟小鼠EHEC样感染的建立.这项研究强烈表明,提供阻断肠道病原体定植因子的有效载荷的智能微生物可以被开发为对抗细菌感染的抗生素的急需替代品。
    Engineered smart microbes that deliver therapeutic payloads are emerging as treatment modalities, particularly for diseases with links to the gastrointestinal tract. Enterohemorrhagic E coli (EHEC) is a causative agent of potentially lethal hemolytic uremic syndrome. Given concerns that antibiotic treatment increases EHEC production of Shiga toxin (Stx), which is responsible for systemic disease, novel remedies are needed. EHEC encodes a type III secretion system (T3SS) that injects Tir into enterocytes. Tir inserts into the host cell membrane, exposing an extracellular domain that subsequently binds intimin, one of its outer membrane proteins, triggering the formation of attaching and effacing (A/E) lesions that promote EHEC mucosal colonization. Citrobacter rodentium (Cr), a natural A/E mouse pathogen, similarly requires Tir and intimin for its pathogenesis. Mice infected with Cr(ΦStx2dact), a variant lysogenized with an EHEC-derived phage that produces Stx2dact, develop intestinal A/E lesions and toxin-dependent disease. Stx2a is more closely associated with human disease. By developing an efficient approach to seamlessly modify the C. rodentium genome, we generated Cr_Tir-MEHEC(ΦStx2a), a variant that expresses Stx2a and the EHEC extracellular Tir domain. We found that mouse pre-colonization with HS-PROT3EcT-TD4, a human commensal E. coli strain (E. coli HS) engineered to efficiently secrete- an anti-EHEC Tir nanobody, delayed bacterial colonization and improved survival after challenge with Cr_Tir-MEHEC(ΦStx2a). This study provides the first evidence to support the efficacy of engineered commensal E. coli to intestinally deliver therapeutic payloads that block essential enteric pathogen virulence determinants, a strategy that may serve as an antibiotic-independent antibacterial therapeutic modality.
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  • 文章类型: Journal Article
    铜绿假单胞菌是一种非常有弹性的机会致病菌,由于其发展耐药性的倾向,给治疗带来了巨大的挑战。为了解决这个困境,我们设计了一种自组装的超分子抗生素,称为dHTSN1@pHPplus,通过抑制Ⅲ型分泌系统,阻碍关键毒力因子的分泌,同时动员免疫细胞根除铜绿假单胞菌,从而规避铜绿假单胞菌的耐药机制,有效对抗铜绿假单胞菌感染。此外,dHTSN1@pHPplus巧妙地设计了感染靶向能力,使它能够有选择地精确地集中在感染部位。如预期,在铜绿假单胞菌肺部感染小鼠模型中,dHTSN1@pHPplus在对抗美罗培南和亚胺培南双重耐药方面表现出显著的治疗效果。宏基因组检测的结果进一步证实了这些发现,与未处理的铜绿假单胞菌感染肺的小鼠相比,铜绿假单胞菌的比例显着降低。此外,在急性毒性实验中未观察到明显的急性毒性。本研究得出结论,dHTSN1@pHPplus在治疗耐药铜绿假单胞菌感染中的显着功效证实了其作为对抗耐药铜绿假单胞菌的开创性抗生素的巨大潜力。
    The bacterium Pseudomonas aeruginosa is an exceptionally resilient opportunistic pathogen, presenting formidable challenges for treatment due to its proclivity for developing drug resistance. To address this predicament, we have devised a self-assembled supramolecular antibiotic known as dHTSN1@pHPplus, which can circumvent the drug resistance mechanism of Pseudomonas aeruginosa and effectively combat Pseudomonas aeruginosa infection by impeding the secretion of key virulence factors through the inhibition of the type III secretion system while simultaneously mobilizing immune cells to eradicate Pseudomonas aeruginosa. Furthermore, dHTSN1@pHPplus was ingeniously engineered with infection-targeting capabilities, enabling it to selectively concentrate precisely at the site of infection. As anticipated, the administration of dHTSN1@pHPplus exhibited a remarkable therapeutic efficacy in combating dual resistance to Meropenem and imipenem in a mouse model of P. aeruginosa lung infection. The results obtained from metagenomic detection further confirmed these findings, demonstrating a significant reduction in the proportion of Pseudomonas aeruginosa compared to untreated mice with Pseudomonas aeruginosa-infected lungs. Additionally, no notable acute toxicity was observed in the acute toxicity experiments. The present study concludes that the remarkable efficacy of dHTSN1@pHPplus in treating drug-resistant P. aeruginosa infection confirms its immense potential as a groundbreaking antibiotic agent for combating drug-resistant P. aeruginosa.
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  • 文章类型: Journal Article
    尽管被认为是正常菌群,Providenciaalcalifaciens可引起腹泻。在之前的研究中,菌株2939/90,从腹泻患者获得,引起哺乳动物细胞的入侵和肌动蛋白缩合,和兔子模型的腹泻。2939/90的四个TnphoA突变体在哺乳动物细胞中产生可忽略的侵袭和肌动蛋白缩合。现在,亲本菌株和突变体已被测序以定位TnphoA插入位点并确定对毒力的影响。在大质粒上的三型分泌系统(T3SS)基因座中检测到TnphoA插入,而在染色体上的T3SS基因座中未检测到。在所调查的52个基因组中,染色体T3SS位点存在于所有菌株中,包括产钙假单胞菌基因组进化枝,我们将其分为A组和B组。质粒T3SS存在于52个基因组中的21个,主要在A组基因组中,其中包括狗出血性腹泻爆发的分离株。TnphoA插入仅在质粒T3SS位点影响侵袭表型,表明该位点对腹泻的病因至关重要。我们得出的结论是,具有这种质粒介导的T3SS的巴氏疟原虫亚群是一种可引起腹泻疾病的肠道病原体。
    Despite being considered a normal flora, Providencia alcalifaciens can cause diarrhea. In a previous study, strain 2939/90, obtained from a diarrheal patient, caused invasion and actin condensation in mammalian cells, and diarrhea in a rabbit model. Four TnphoA mutants of 2939/90 produced negligible invasion and actin condensation in mammalian cells. Now, the parent strain and the mutants have been sequenced to locate TnphoA insertion sites and determine the effect on virulence. A TnphoA insertion was detected in the type three secretion system (T3SS) locus on a large plasmid and not in a T3SS locus on the chromosome. In 52 genomes of P. alcalifaciens surveyed, the chromosomal T3SS locus was present in all strains, including both P. alcalifaciens genomic clades, which we classified as group A and group B. Plasmid T3SS was present in 21 of 52 genomes, mostly in group A genomes, which included isolates from an outbreak of hemorrhagic diarrhea in dogs. The TnphoA insertion only in the plasmid T3SS locus affected the invasion phenotype, suggested that this locus is critical for causation of diarrhea. We conclude that a subgroup of P. alcalifaciens that possesses this plasmid-mediated T3SS is an enteric pathogen that can cause diarrheal disease.
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  • 文章类型: Journal Article
    目前,人们普遍认为III型分泌系统(T3SS)是细菌毒力因子的转运平台,而鞭毛充当推进马达。然而,对于阐明这两种机制之间的功能差异的比较研究,仍然存在明显的缺乏。昆虫病原线虫共生细菌(ENS),包括横纹肌和光纹肌,是通过Steinernema或Heterorhabdus运输到昆虫宿主中的革兰氏阴性细菌。鞭毛在ENS中保存,但是T3SS只编码在光纹针中。关于鞭毛和T3SS在ENS中的功能的报道很少,不知道它们在感染ENS中起什么作用。这里,我们根据X.storiae(flhDC缺失)的鞭毛失活,阐明了T3SS和鞭毛在ENS感染中的功能,T3SS在发光假单胞菌中的失活(sctV缺失),以及X.stockiae中发光假单胞菌T3SS的异源合成。与以前的结果一致,ENS的蜂拥运动和生物膜的形成由鞭毛主导。T3SS和鞭毛都促进ENS在宿主细胞内的侵袭和定植,对次生代谢产物的形成和分泌影响最小。出乎意料的是,蛋白质组学分析揭示了鞭毛/T3SS组装体和VI型分泌系统(T6SS)之间的负反馈环。RT-PCR测试表明T3SS对鞭毛组装的抑制作用,而鞭毛蛋白表达促进T3SS组装。此外,T3SS表达刺激核糖体相关蛋白表达。
    Currently, it is widely accepted that the type III secretion system (T3SS) serves as the transport platform for bacterial virulence factors, while flagella act as propulsion motors. However, there remains a noticeable dearth of comparative studies elucidating the functional disparities between these two mechanisms. Entomopathogenic nematode symbiotic bacteria (ENS), including Xenorhabdus and Photorhabdus, are Gram-negative bacteria transported into insect hosts by Steinernema or Heterorhabdus. Flagella are conserved in ENS, but the T3SS is only encoded in Photorhabdus. There are few reports on the function of flagella and the T3SS in ENS, and it is not known what role they play in the infection of ENS. Here, we clarified the function of the T3SS and flagella in ENS infection based on flagellar inactivation in X. stockiae (flhDC deletion), T3SS inactivation in P. luminescens (sctV deletion), and the heterologous synthesis of the T3SS of P. luminescens in X. stockiae. Consistent with the previous results, the swarming movement of the ENS and the formation of biofilms are dominated by the flagella. Both the T3SS and flagella facilitate ENS invasion and colonization within host cells, with minimal impact on secondary metabolite formation and secretion. Unexpectedly, a proteomic analysis reveals a negative feedback loop between the flagella/T3SS assembly and the type VI secretion system (T6SS). RT-PCR testing demonstrates the T3SS\'s inhibition of flagellar assembly, while flagellin expression promotes T3SS assembly. Furthermore, T3SS expression stimulates ribosome-associated protein expression.
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  • 文章类型: Journal Article
    白三烯B4(LTB4)对于响应感染而启动炎症级联反应至关重要。然而,鼠疫耶尔森氏菌通过抑制LTB4的及时合成和炎症而定植宿主。这里,我们表明,细菌3型分泌系统(T3SS)是主要的病原体相关分子模式(PAMP),负责白细胞响应耶尔森氏菌和沙门氏菌产生LTB4,但是在耶尔森氏菌相互作用期间,Yop效应子抑制了合成。此外,我们意外地发现,T3SS介导的嗜中性粒细胞和巨噬细胞的LTB4合成需要两种不同的宿主信号通路.我们表明,SKAP2/PLC信号通路对于中性粒细胞而不是巨噬细胞产生LTB4至关重要。相反,巨噬细胞合成LTB4需要吞噬作用和NLRP3/CASP1炎性体。最后,虽然LTB4生产需要识别T3SS,我们还发现第二个无关的PAMP介导的信号独立激活LTB4合成所需的MAP激酶途径。一起,这些数据表明巨噬细胞和中性粒细胞对细菌感染快速反应所需的信号通路存在显著差异.
    宿主产生炎性脂质介质对于响应细菌病原体入侵的及时炎症至关重要。因此,确定免疫细胞如何识别病原体并快速产生这些脂质对于我们了解免疫系统如何有效控制感染至关重要。在这项研究中,我们发现白细胞三烯B4(LTB4)合成所需的宿主信号通路在中性粒细胞和巨噬细胞之间不同,强调免疫细胞对感染反应的重要差异。一起,这些数据表明,我们对中性粒细胞和巨噬细胞如何迅速与细菌发生反应的认识有了显著提高,并为鼠疫耶尔森氏菌如何操纵白细胞逃避免疫识别而导致疾病提供了新的见解.
    Leukotriene B4 (LTB4) is critical for initiating the inflammatory cascade in response to infection. However, Yersinia pestis colonizes the host by inhibiting the timely synthesis of LTB4 and inflammation. Here, we show that the bacterial type 3 secretion system (T3SS) is the primary pathogen associated molecular pattern (PAMP) responsible for LTB4 production by leukocytes in response to Yersinia and Salmonella, but synthesis is inhibited by the Yop effectors during Yersinia interactions. Moreover, we unexpectedly discovered that T3SS-mediated LTB4 synthesis by neutrophils and macrophages require two distinct host signaling pathways. We show that the SKAP2/PLC signaling pathway is essential for LTB4 production by neutrophils but not macrophages. Instead, phagocytosis and the NLRP3/CASP1 inflammasome are needed for LTB4 synthesis by macrophages. Finally, while recognition of the T3SS is required for LTB4 production, we also discovered a second unrelated PAMP-mediated signal independently activates the MAP kinase pathway needed for LTB4 synthesis. Together, these data demonstrate significant differences in the signaling pathways required by macrophages and neutrophils to quickly respond to bacterial infections.
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  • 文章类型: Journal Article
    皮爱德华氏菌是一种急性海洋病原体,对全球水产养殖业造成严重破坏。皮西氏菌的发病机制主要依赖于III型分泌系统(T3SS)和VI型分泌系统(T6SS),两者都受到EsrB和EsrC的严格监管。在这项研究中,我们发现脂肪酸影响T3SS表达。不饱和脂肪酸(UFA),但不是饱和脂肪酸(SFA),直接与EsrC交互,这取消了EsrC的功能并导致T3/T6SS的关闭。此外,在皮西西氏菌的体内定植过程中,观察到宿主脂肪酸通过FadL转运到双歧杆菌中并调节T3/T6SS的表达。此外,esrCR38G突变体阻断了EsrC和UFA之间的相互作用,导致DMEM的显着生长缺陷和HeLa细胞和斑马鱼的定植受损。总之,这项研究表明,UFA和EsrC之间的相互作用以关闭T3/T6SS表达对于piscicida感染至关重要。
    Edwardsiella piscicida is an acute marine pathogen that causes severe damage to the aquaculture industry worldwide. The pathogenesis of E. piscicida is dependent mainly on the type III secretion system (T3SS) and type VI secretion system (T6SS), both of which are critically regulated by EsrB and EsrC. In this study, we revealed that fatty acids influence T3SS expression. Unsaturated fatty acids (UFAs), but not saturated fatty acids (SFAs), directly interact with EsrC, which abolishes the function of EsrC and results in the turn-off of T3/T6SS. Moreover, during the in vivo colonization of E. piscicida, host fatty acids were observed to be transported into E. piscicida through FadL and to modulate the expression of T3/T6SS. Furthermore, the esrCR38G mutant blocked the interaction between EsrC and UFAs, leading to dramatic growth defects in DMEM and impaired colonization in HeLa cells and zebrafish. In conclusion, this study revealed that the interaction between UFAs and EsrC to turn off T3/T6SS expression is essential for E. piscicida infection.
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  • 文章类型: Journal Article
    米黄单胞菌(Xoo)引起的细菌性叶枯病(BLB)对水稻生产极为有害。传统的控制方法是使用针对关键细菌生长因子的杀菌剂,但是病原体的选择压力使抗性菌株成为优势菌株,导致杀菌效果下降。III型分泌系统(T3SS)是大多数革兰氏阴性菌中保守的关键毒力因子,它的表达或缺失不会影响细菌生长,使其成为制造针对革兰氏阴性病原体的药物的理想目标。在这项工作中,我们合成了一系列来自cryptolepine和neocryptolepine的衍生物。我们发现,化合物Z-8可以抑制XooT3SS相关基因的表达,而不影响细菌的生长。体内生物测定表明,化合物Z-8可以有效降低Xoo在烟草中引起的超敏反应(HR),并降低Xoo在水稻中的致病性。此外,当与群体猝灭细菌F20结合时,它在控制细菌性叶枯病方面表现出协同作用。
    Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv oryzae (Xoo) is extremely harmful to rice production. The traditional control approach is to use bactericides that target key bacterial growth factors, but the selection pressure on the pathogen makes resistant strains the dominant bacterial strains, leading to a decline in bactericidal efficacy. Type III secretion system (T3SS) is a conserved and critical virulence factor in most Gram-negative bacteria, and its expression or absence does not affect bacterial growth, rendering it an ideal target for creating drugs against Gram-negative pathogens. In this work, we synthesized a range of derivatives from cryptolepine and neocryptolepine. We found that compound Z-8 could inhibit the expression of Xoo T3SS-related genes without affecting the growth of bacteria. an in vivo bioassay showed that compound Z-8 could effectively reduce the hypersensitive response (HR) induced by Xoo in tobacco and reduce the pathogenicity of Xoo in rice. Furthermore, it exhibited synergy in control of bacterial leaf blight when combined with the quorum quenching bacterial F20.
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  • 文章类型: Journal Article
    从LaRioja地区(西班牙)的地表水样品中回收铜绿假单胞菌分离株,以表征其抗生素抗性,分子分型和毒力机制。从15个不同的水样中分离出52个铜绿假单胞菌(45.4%),属于23个不同的PFGE模式。所有分离株对所有测试的抗生素都敏感,除了一个耐碳青霉烯的铜绿假单胞菌在OprD孔蛋白中显示过早终止密码子。在29个选定的铜绿假单胞菌中检测到22个序列类型(STs)(六个新的)(每个样品具有不同PFGE模式的菌株),ST274(14%)是最常见的。O:6和O:3是主要的血清型(31%)。检测到7种病毒型,为59%exoS-exoY-exoT-exoA-lasA-lasB-lasI-lasR-rhlAB-rhlI-rhlR-aprA阳性铜绿假单胞菌。值得注意的是,在三个菌株(10.3%)中鉴定了exlA基因,和exoU基因在7(24.1%),在18(62.1%)中,以及一个菌株中的exoS和exoU基因。在这些菌株中发现了高运动性范围。27%的菌株产生了更多的生物膜生物量,90%以上的脓毒苷,83%以上,与PAO1菌株相比,弹性蛋白酶活性为65.5%以上。这些结果突出了河流作为临时水库和铜绿假单胞菌传播源的重要性。并提醒他们在环境中进行流行病学监测的重要性。
    Pseudomonas aeruginosa isolates were recovered from surface river water samples in La Rioja region (Spain) to characterise their antibiotic resistance, molecular typing and virulence mechanisms. Fifty-two P. aeruginosa isolates were isolated from 15 different water samples (45.4%) and belonged to 23 different pulsed-field electrophoresis (PFGE) patterns. All isolates were susceptible to all antibiotics tested, except one carbapenem-resistant P. aeruginosa that showed a premature stop codon in OprD porin. Twenty-two sequence types (STs) (six new ones) were detected among 29 selected P. aeruginosa (one strain with a different PFGE pattern per sample), with ST274 (14%) being the most frequent one. O:6 and O:3 were the predominant serotypes (31%). Seven virulotypes were detected, being 59% exoS-exoY-exoT-exoA-lasA-lasB-lasI-lasR-rhlAB-rhlI-rhlR-aprA-positive P. aeruginosa. It is noteworthy that the exlA gene was identified in three strains (10.3%), and the exoU gene in seven (24.1%), exoS in 18 (62.1%), and both exoS and exoU genes in one strain. High motility ranges were found in these strains. Twenty-seven per cent of strains produced more biofilm biomass, 90% more pyorubin, 83% more pyocyanin and 65.5% more than twice the elastase activity compared with the PAO1 strain. These results highlight the importance of rivers as temporary reservoirs and sources of P. aeruginosa transmission, and show the importance of their epidemiological surveillance in the environment.
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  • 文章类型: Journal Article
    铜绿假单胞菌是在免疫受损个体中引起急性和慢性感染的机会病原体。小调节RNA(sRNA)调节多种细菌对环境变化的适应,尤其是毒力.我们之前的研究表明,PrrHsRNA负调控许多毒力因子的表达,如青苷,鼠李糖脂,生物膜,和弹性蛋白酶在铜绿假单胞菌菌株PAO1中。然而,先前的研究表明,在急性小鼠肺部感染模型中,prrH缺陷型突变体可减弱毒力。所有感染ΔprrH的小鼠在整个28天的实验过程中都存活下来,而接种野生型或互补突变体的所有小鼠在注射后4天内都死于肺部感染,但具体机制尚不清楚。在这里,我们探讨了PrrH如何通过调节毒力因子的表达介导严重肺损伤。小鼠体内和体外细胞实验表明,PrrH增强了PAO1的致病性,引起严重的肺损伤。机械上,PrrH与exsAmRNA的编码序列区结合,编码III型分泌系统主调节蛋白。我们进一步证明了PrrH介导了严重的炎症反应并加剧了A549细胞的凋亡。总的来说,我们的结果表明,PrrH正调节ExsA,增强铜绿假单胞菌的致病性,导致严重的肺损伤.重要铜绿假单胞菌是革兰氏阴性细菌,是医院获得性肺炎的主要原因。铜绿假单胞菌的致病性是由于许多毒力因子的分泌。小调节RNA(sRNA)调节各种细菌适应,尤其是毒力.因此,了解sRNA调节毒力的机制对于了解铜绿假单胞菌的致病性和相关疾病的治疗是必要的。在这项研究中,我们证明了PrrH通过与ExsA的编码序列区结合增强铜绿假单胞菌的致病性,III型分泌系统的主要调节蛋白,引起严重的肺损伤,加剧炎症反应和细胞凋亡。这些发现表明,PrrH是一种积极调节ExsA的关键分子。在临床实践中,III型阳性菌株通常与铜绿假单胞菌感染的高死亡率相关。因此,这一发现可能为治疗铜绿假单胞菌感染提供新的靶点,尤其是III型阳性菌株.
    Pseudomonas aeruginosa is an opportunistic pathogen that causes acute and chronic infections in immunocompromised individuals. Small regulatory RNAs (sRNAs) regulate multiple bacterial adaptations to environmental changes, especially virulence. Our previous study showed that sRNA PrrH negatively regulates the expression of a number of virulence factors, such as pyocyanin, rhamnolipid, biofilm, and elastase in the P. aeruginosa strain PAO1. However, previous studies have shown that the prrH-deficient mutant attenuates virulence in an acute murine lung infection model. All ΔprrH-infected mice survived the entire 28-day course of the experiment, whereas all mice inoculated with the wild-type or the complemented mutant succumbed to lung infection within 4 days of injection, but the specific mechanism is unclear. Herein, we explored how PrrH mediates severe lung injury by regulating the expression of virulence factors. In vivo mouse and in vitro cellular assays demonstrated that PrrH enhanced the pathogenicity of PAO1, causing severe lung injury. Mechanistically, PrrH binds to the coding sequence region of the mRNA of exsA, which encodes the type III secretion system master regulatory protein. We further demonstrated that PrrH mediates a severe inflammatory response and exacerbates the apoptosis of A549 cells. Overall, our results revealed that PrrH positively regulates ExsA, enhances the pathogenicity of P. aeruginosa, and causes severe lung injury.
    OBJECTIVE: Pseudomonas aeruginosa is a Gram-negative bacterium and the leading cause of nosocomial pneumonia. The pathogenicity of P. aeruginosa is due to the secretion of many virulence factors. Small regulatory RNAs (sRNAs) regulate various bacterial adaptations, especially virulence. Therefore, understanding the mechanism by which sRNAs regulate virulence is necessary for understanding the pathogenicity of P. aeruginosa and the treatment of the related disease. In this study, we demonstrated that PrrH enhances the pathogenicity of P. aeruginosa by binding to the coding sequence regions of the ExsA, the master regulatory protein of type III secretion system, causing severe lung injury and exacerbating the inflammatory response and apoptosis. These findings revealed that PrrH is a crucial molecule that positively regulates ExsA. Type III-positive strains are often associated with a high mortality rate in P. aeruginosa infections in clinical practice. Therefore, this discovery may provide a new target for treating P. aeruginosa infections, especially type III-positive strains.
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