摘要：
Mycoplasma pneumoniae is an obligate pathogen that causes pneumonia, tracheobronchitis, pharyngitis and asthma in humans. It is well recognized that membrane lipoproteins are immunostimulants exerting as lipopolysaccharides (LPS) and play a crucial role in the pathogenesis of inflammatory responses upon M. pneumoniae infection. Here, we report that the M. pneumoniae-derived lipids are another proinflammatory agents. Using an antibody-neutralizing assay, RNA interference or specific inhibitors, we found that Toll-like receptor 4 (TLR-4) is essential for M. pneumoniae lipid-induced tumour necrosis factor (TNF)-α and interleukin (IL)-1β production. We also demonstrate that NLR family pyrin domain containing 3 inflammasome (NLRP3) inflammasome, autophagy and nuclear factor kappa B (NF-κB)-dependent pathways are critical for the secretion of proinflammatory cytokines, while inhibition of TLR-4 significantly abrogates these events. Further characterization revealed that autophagy-mediated inflammatory responses involved the activation of NF-κB. In addition, the activation of NF-κB promoted lipid-induced autophagosome formation, as revealed by assays using pharmacological inhibitors, 3-methyladenine (3-MA) and Bay 11-7082, or silencing of atg5 and beclin-1. These findings suggest that, unlike the response to lipoprotein stimulation, the inflammation in response to M. pneumoniae lipids is mediated by the TLR-4 pathway, which subsequently initiates the activation of NLRP3 inflammasome and formation of a positive feedback loop between autophagy and NF-κB signalling cascade, ultimately promoting TNF-α and Il-1β production in macrophages.
TLR4 is usually not assumed to be involved in Mycoplasma recognition. In this study we showed that the Mycoplasma pneumoniae-derived lipids did interact with TLR4 which subsequently initiates the activation of NLRP3 inflammasome and formation of a positive feedback loop between autophagy and NF-κB signalling cascade, ultimately promoting proinflammatory cytokines production in macrophages.
通讯机构：
[Wan, YP; Wu, YM] U;Univ South China, Pathogen Biol Inst, Hengyang 421001, Peoples R China.
关键词：
Human papillomavirus type16;E6 protein;Death domain associated protein;Proliferation;Apoptosis;Caspase-8
摘要：
Daxx is a highly conserved nuclear protein with an important role in transcription, apoptosis and other cell processes. We investigated the role of HPV16 E6 in Daxx-induced apoptosis through their interactions in C33A cells. The binding of HPV16 E6 and Daxx was confirmed in C33A cells using co-immunoprecipitation and indirect immunofluorescence assays. Quantitative PCR and western blotting were performed to determine the RNA and protein expressions of Daxx, respectively. Automatic cell count and MTT assays were performed to investigate the proliferation of C33A cells. The apoptosis rate of C33A cells was determined via flow cytometry using Annexin V-FITC/PI staining. The relative activity of caspase-8 was tested using ELISA. HPV16 E6 can bind with Daxx and cause its translocation in C33A cells. The transfected HPV16 E6 can cause a decrease in relative quantification for Daxx in Daxx-overexpressing cells. After Daxx transfection, cell proliferation was found to decrease sharply and cell apoptosis to increase sharply. However, when HPV16 E6 was co-transfected with Daxx, this decrease and increase both became gentle. Similarly, HPV16 E6 made the Daxx-induced increase in caspase-8 activity milder. HPV16 E6 is involved in inhibiting apoptosis through deregulation of Daxx-induced caspase-8 activities.
作者机构：
[周安文; 罗良贤; 李佳艳] Chlamydia R&D Center of Chenzhou, Chenzhou NO.1 People's Hospital, Chenzhou, 423000, China;[何蓓; 周洲; 吴移谋] Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, 421001, China;Department of Laboratory Medicine, Chenzhou Hospital Affiliated to Southern Medical University, Chenzhou, 423000, China;[陈虹亮] Chlamydia R&D Center of Chenzhou, Chenzhou NO.1 People's Hospital, Chenzhou, 423000, China, Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, 421001, China, Department of Laboratory Medicine, Chenzhou Hospital Affiliated to Southern Medical University, Chenzhou, 423000, China;[李胜涛; 江扬华] Chlamydia R&D Center of Chenzhou, Chenzhou NO.1 People's Hospital, Chenzhou, 423000, China, Department of Laboratory Medicine, Chenzhou Hospital Affiliated to Southern Medical University, Chenzhou, 423000, China
通讯机构：
[Chen, H.] C;Chlamydia R&D Center of Chenzhou, China
摘要：
Chlamydia psittaci is a zoonotic pathogen with multiple hosts, especially avian, and can be transmitted to humans, causing psittacosis or ornithosis. No effective vaccines have been developed. We therefore isolate and genotype avian C. psittaci strains and investigate the pathogenicity of isolates in the southern Hunan area of China. Among 200 suspicious avian specimens, eight were positive for the C. psittaci outer membrane protein A (ompA) gene (4%), and seven were successfully cultured in human epithelial type 2 and Vero cells (87.5%). Genotyping of the ompA gene of the eight PCR-positive samples revealed that all of the cultured strains, except for the E9 strain, belonged to genotype A. Pathologic changes in the mice infected with C. psittaci via intranasal inoculation showed severe pneumonia and intense infiltration of inflammatory cells in the lung in a dose-dependent manner, and immunohistochemical staining displayed different levels of infiltration of C. psittaci inclusions in the heart, liver, spleen, kidney, and, especially, lung. Our findings demonstrate that genotype A dominates all C. psittaci genotypes in the southern Hunan area and that the C. psittaci avian isolates in this region possess dose-dependent pathogenicity.
摘要：
Background: Chlamydia psittaci is a zoonotic bacteria closely associated with psittacosis/ornithosis. Vaccination has been recognized as the best way to inhibit the spread of C. psittaci due to the majority ignored of infections. The optimal Chlamydia vaccine was obstructed by the defect of single immunization route and the lack of availability of nontoxic and valid adjuvants. Methods: In this study, we developed a novel immunization strategy, simultaneous (SIM) intramuscular (IM) and intranasal (IN) administration of a C. psittaci antigens (Ags) adjuvanted with chitosan nanoparticles (CNPs). And SIM-CNPs-Ags were used to determine the different types of immune response and the protective role in vivo. Results: CNPs-Ags with zeta-potential values of 13.12 mV and of 276.1 nm showed excellent stability and optimal size for crossing the mucosal barrier with high 71.7% encapsulation efficiency. SIM-CPN-Ags mediated stronger humoral and mucosal responses by producing meaningfully high levels of IgG and secretory IgA (sIgA) antibodies. The SIM route also led to Ags-specific T-cell responses and increased IFN-gamma, IL-2, TNF-alpha and IL-17A in the splenocyte supernatants. Following respiratory infection with C. psittaci, we found that SIM immunization remarkably reduced bacterial load and the degree of inflammation in the infected lungs and made for a lower level of IFN-gamma, TNF-alpha and IL-6. Furthermore, SIM vaccination with CNPs-Ags had obviously inhibited C. psittaci disseminating to various organs in vivo. Conclusion: SIM immunization with CNPs-adjuvanted C. psittaci Ags may present a novel strategy for the development of a vaccine against the C. psittaci infection.
摘要：
Syphilis is a chronic bacterial infection caused by Treponema pallidum (T pallidum) and the pathogenesis that T pallidum infection induces immunopathological damages in skin and other tissues remains unclear. We have previously reported that recombinant flagellins of T pallidum can elicit IL-6 and IL-8 transcriptions via TLR5 pathway. To identify the domains which induced the pro-inflammatory activity and the importance of the interactions between TLR5 and domains, homology-based modelling and comparative structural analyses revealed that Tpflagellins can combine with TLR5 directly. Deletion mutations showed that the ND1 domain binding to TLR5 is required but not sufficient in TLR5 activation. Moreover, site-directed mutagenesis analysis indicated that the arginine residue (Tpflagellins R89) of the ND1 domain and its adjacent residues (Tpflagellins L93 and E113) constitute a hot spot that elicits IL-6, IL-8 transcriptions and TLR5 activation, and affects the binding of Tpflagellins to TLR5. Taken together, these results give insight into the pathogenesis of T pallidum and may contribute to the future design of Tpflagellins-based therapeutics and syphilis vaccine.
摘要：
Chlamydia psittaci is an obligate intracellular pathogen with a biphasic developmental life cycle. It is auxotrophic for a variety of essential metabolites and obtains amino acids from eukaryotic host cells. Chlamydia can develop inside host cells within chlamydial inclusions. A pathway secreting proteins from inclusions into the host cellular cytoplasm is the type III secretion system (T3SS). The T3SS is universal among several Gram-negative bacteria. Here, we show that CPSIT_0959 of C. psittaci is expressed midcycle and secreted into the infected cellular cytoplasm via the T3SS. Recombinant CPSIT_0959 possesses cysteine desulfurase and PLP-binding activity, which removes sulfur from cysteine to produce alanine, and helps chlamydial replication. Our study shows that CPSIT_0959 improve the infectivity of offspring elementary bodies and seems to promote the replication by its product. This phenomenon has inhibited by the PLP-dependent enzymes inhibitor. Moreover, CPSIT_0959 increased expression of Bim and tBid, and decreased the mitochondrial membrane potential of host mitochondria to induce apoptosis in the latecycle for release of offspring. These results demonstrate that CPSIT_0959 has cysteine desulfurase and PLP-binding activity and is likely to contribute to apoptosis of the infected cells via a mitochondria-mediated pathway to improve the infectivity of progeny.
摘要：
Exposure to Mycoplasma pneumoniae leads to lung inflammation through a host defense pathway. Increasing evidence has indicated that the mycoplasma-derived membrane lipoprotein, or its analogue macrophage-activating lipopeptide-2 (MALP-2), excretes LPS as an immune system-stimulating substance and plays a crucial role in pathological injury during M. pneumoniae infection. It has been established that Sulforaphane confers anti-inflammatory properties. However, the underlying mechanism responsible for the inhibitory actions of Sulforaphane in the context of mycoplasmal pneumoniae are poorly understood. Here, we report that Sulforaphane is an inducer of heme oxygenase (HO)-1, a cytoprotective enzyme that catalyzes the degradation of heme through signaling pathways in human monocytes. Sulforaphane stimulated NF-E2-related factor 2 (Nrf2) translocation from the cytosol to the nucleus, and small interfering RNA-mediated knock-down of Nrf2 significantly inhibited Sulforaphane-induced HO-1 expression. Additionally, PI3K/Akt and ROS were also involved in Sulforaphane-induced Nrf2 activation and HO-1 expression, as revealed by the pharmacological inhibitors LY294002 and NAC. Moreover, Sulforaphane treatment inhibited MALP-2-induced pro-inflammatory cytokine secretion and pulmonary inflammation in mice, as well as MALP-2-triggered NF-kappaB activation. Furthermore, SnPP, a selective inhibitor of HO-1, reversed the inhibitory actions of Sulforaphane, while a carbon monoxide-releasing molecule, CORM-2, caused a significant decrease in MALP-2-induced cytokine secretion. Collectively, these results suggest that Sulforaphane functions as a suppressor of the MALP-2-induced inflammatory response, not only by inhibiting the expression of cytokines and the induction of HO-1 but also by diminishing NF-kappaB activation in cultured monocytes and the lungs of mice.
摘要：
Although Chlamydia has been frequently detected in the gastrointestinal tracts of both humans and animals, it is not associated with any gastrointestinal pathology. We have recently shown that gastrointestinal Chlamydia muridarum is not only non-pathogenic but also induces protective immunity in the genital tract. We now report that the transmucosal immunity induced by a single oral immunization with C. muridarum protected the mouse airway from a subsequent challenge infection. The oral immunization significantly reduced chlamydial burden in the airway as early as day 3 after intranasal challenge. As a result, the airway chlamydial spreading to extra-airway tissues was completely prevented on day 3 and significantly reduced on day 9. The immunized mice were protected from any significant systemic toxicity caused by the intranasal challenge since there was no significant bodyweight drop in the immunized mice. This robust protection correlated well with Chlamydia-specific antibodies that recognize chlamydial organism surface antigens and T cell responses that are dominated with a Th1 phenotype. The immunized mice developed high ratios of IgG2b/c over IgG1 levels and IFN gamma-producing over IL-5 or IL-13-producing lymphocytes. Thus, we have demonstrated that oral vaccination with C muridarum can induce Th1-dominant transmucosal immunity in the airway. Together with previous studies, we propose that non-pathogenic colonization of Chlamydia in the gastrointestinal tract be explored as an oral delivery system for inducing protection against infections and pathologies in extra-gastrointestinal tissues. (C) 2018 Elsevier Ltd. All rights reserved.
