EseN is an
This work has global significance in the catfish industry, which provides food for increasing global populations.
- Award ID(s):
- 1736253
- NSF-PAR ID:
- 10291351
- Date Published:
- Journal Name:
- Viruses
- Volume:
- 12
- Issue:
- 9
- ISSN:
- 1999-4915
- Page Range / eLocation ID:
- 932
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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ABSTRACT Edwardsiella ictaluri type III secretion system effector with phosphothreonine lyase activity. In this work, we demonstrate that EseN inactivates p38 and c-Jun-N-terminal kinase (JNK) in infected head-kidney-derived macrophages (HKDMs). We have previously reported inactivation of extracellular-regulated kinase 1/2 (ERK1/2). Also, for the first time, we demonstrated that EseN is involved in the inactivation of 3-phosphoinositide-dependent kinase 1 (PDK1), which has not been previously demonstrated for any of the EseN homologs in other species. We also found that EseN significantly affected mRNA expression ofIL-10 , pro-apoptoticbaxa , andp53 , but had no significant effect on anti-apoptoticbcl2 or pro-apoptotic apoptotic peptidase activating factor 1. EseN is also involved in the inhibition of caspase-8 and caspase-3/7 but does not affect caspase-9 activity. Repression of apoptosis was further confirmed with flow cytometry using Alexa Fluor 647-labeled annexin V and propidium iodide. In addition, we found that theE. ictaluri T3SS is essential for the inhibition of IL-1β maturation, but EseN is not involved in this process. EseN did not affect cell pyroptosis, as indicated by the lack of EseN impact on the release of lactate dehydrogenase from infected HKDM. The transmission electron microscopy data also indicate that HKDM infected with WT or aneseN mutant died by apoptosis, while HKDM infected with the T3SS mutant more likely died by pyroptosis. Collectively, our results indicate thatE. ictaluri EseN is involved in inactivation of ERK1/2, p38, JNK, and PDK1 signaling pathways that lead to modulation of cell death among infected HKDMs.IMPORTANCE E. ictaluri is a leading cause of disease loss, and EseN is an important player inE. ictaluri virulence. TheE. ictaluri T3SS effector EseN plays an essential role in establishing infection, but the specific role EseN plays is not well characterized. EseN belongs to a family of phosphothreonine lyase effectors that specifically target host mitogen activated protein kinase (MAPK) pathways important in regulating host responses to infection. No phosphothreonine lyase equivalents are known in eukaryotes, making this family of effectors an attractive target for indirect narrow-spectrum antibiotics. Targeting of major vault protein and PDK1 kinase by EseN has not been reported in EseN homologs in other pathogens and may indicate unique functions ofE. ictaluri EseN. EseN targeting of PDK1 is particularly interesting in that it is linked to an extraordinarily diverse group of cellular functions. -
Necroptosis is a type of programed cell death characterized by an inflammatory phenotype due to extensive membrane permeabilization and rupture. Initiation of necroptosis involves activation of tumor necrosis factor receptors by tumor necrosis factor alpha (TNFα) followed by coordinated activities of receptor-interacting protein kinases and mixed lineage kinase-like protein (MLKL). Subsequently, MLKL undergoes phosphorylation and translocates to the plasma membrane, leading to permeabilization. Such permeabilization results in the release of various cytokines and causes extensive inflammatory activity at the organismal level. This inflammatory activity is one of the major differences between apoptosis and necroptosis and links necroptosis to several human pathologies that exhibit inflammation, in addition to the ultimate cell death phenotype. Given the crosstalk between the activation of cell death pathway and inflammatory activity, approaches that provide insights on the regulation of transcripts, proteins and their processing at the global level have substantially improved our understanding of necroptosis and its involvement in different disease states. In this review, we highlight recent omic studies probing the transcriptome, proteome and lipidome which elucidate potential new mechanisms and signaling pathways during necroptosis and the necroptosis-associated inflammatory activity observed in various diseases. We specifically focus on studies investigating the transcriptome and intracellular and released proteome that contribute to inflammatory nature of necroptotic cells. We also highlight different lipids that have been implicated in necroptosis and lipidomic studies identifying lipid players in necroptosis. Finally, we review studies which suggest certain necroptosis-related genes as potential prognosis markers for different cancers and discuss their translational implications.more » « less
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Jung, Jae U. (Ed.)ABSTRACT Ranaviruses such as frog virus 3 (FV3) are large double-stranded DNA (dsDNA) viruses causing emerging infectious diseases leading to extensive morbidity and mortality of amphibians and other ectothermic vertebrates worldwide. Among the hosts of FV3, some are highly susceptible, whereas others are resistant and asymptomatic carriers that can take part in disseminating the infectious virus. To date, the mechanisms involved in the processes of FV3 viral persistence associated with subclinical infection transitioning to lethal outbreaks remain unknown. Investigation in Xenopus laevis has revealed that in asymptomatic FV3 carrier animals, inflammation induced by heat-killed (HK) Escherichia coli stimulation can provoke the relapse of active infection. Since Toll-like receptors (TLRs) are critical for recognizing microbial molecular patterns, we investigated their possible involvement in inflammation-induced FV3 reactivation. Among the 10 different TLRs screened for changes in expression levels following FV3 infection and HK E. coli stimulation, only TLR5 and TLR22, both of which recognize bacterial products, showed differential expression, and only the TLR5 ligand flagellin was able to induce FV3 reactivation similarly to HK E. coli . Furthermore, only the TLR5 ligand flagellin induced FV3 reactivation in peritoneal macrophages both in vitro and in vivo . These data indicate that the TLR5 signaling pathway can trigger FV3 reactivation and suggest a role of secondary bacterial infections or microbiome alterations (stress or pollution) in initiating sudden deadly disease outbreaks in amphibian populations with detectable persistent asymptomatic ranavirus. IMPORTANCE This study in the amphibian Xenopus laevis provides new evidence of the critical role of macrophages in the persistence of ranaviruses in a quiescent state as well as in the reactivation of these pathogens into a virulent infection. Among the multiple microbial sensors expressed by macrophages, our data underscore the preponderant involvement of TLR5 stimulation in triggering the reactivation of quiescent FV3 in resident peritoneal macrophages, unveiling a mechanistic connection between the reactivation of persisting ranavirus infection and bacterial coinfection. This suggests a role for secondary bacterial infections or microbiome alterations (stress or pollution) in initiating sudden deadly disease outbreaks in amphibian populations with detectable persistent asymptomatic ranavirus.more » « less
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Abstract Background H7N9 avian influenza is an infection of public health concern, in part because of its high mortality rate and pandemic potential.
Aims To describe the clinical features of H7N9 avian influenza and the response to treatment.
Methods Clinical, radiological and histopathological data, and treatment‐related of H7N9‐infected patients hospitalised during 2014–2017 were extracted and analysed.
Results A total of 17 H7N9 patients (three females; mean age, 58.4 ± 13.7 years) was identified; of these six died. All patients presented with fever and productive cough; four patients had haemoptysis and 13 had chest distress and/or shortness of breath. Early subnormal white blood cell count and elevation of serum liver enzymes were common. Multilobar patchy shadows, rapid progression to ground‐glass opacities, air bronchograms and consolidation were the most common imaging findings. Histopathological examination of lung tissue of three patients who died showed severe alveolar epithelial cell damage, with inflammatory exudation into the alveolar space and hyaline membrane formation; widened alveolar septae, prominent inflammatory cell infiltration; and hyperplasia of pneumocytes. Viral inclusions were found in the lung tissue of two patients. All patients received antiviral drugs (oseltamivir ± peramivir). Four patients carried the rs12252‐C/C interferon‐induced transmembrane protein‐3 (IFITM3) genotype, while the others had the C/T genotype.
Conclusions H7N9 virus infection causes human influenza‐like symptoms, but may rapidly progress to severe pneumonia and even death. Clinicians should be alert to the possibility of H7N9 infection in high‐risk patients. The presence of the
IFITM3 rs12252‐C genotype may predict severe illness. -
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Abstract Previous urinary tract infections (UTIs) can predispose one to future infections; however, the underlying mechanisms affecting recurrence are poorly understood. We previously found that UTIs in mice cause differential bladder epithelial (urothelial) remodelling, depending on disease outcome, that impacts susceptibility to recurrent UTI. Here we compared urothelial stem cell (USC) lines isolated from mice with a history of either resolved or chronic uropathogenic
Escherichia coli (UPEC) infection, elucidating evidence of molecular imprinting that involved epigenetic changes, including differences in chromatin accessibility, DNA methylation and histone modification. Epigenetic marks in USCs from chronically infected mice enhanced caspase-1-mediated cell death upon UPEC infection, promoting bacterial clearance. IncreasedPtgs2os2 expression also occurred, potentially contributing to sustained cyclooxygenase-2 expression, bladder inflammation and mucosal wounding—responses associated with severe recurrent cystitis. Thus, UPEC infection acts as an epi-mutagen reprogramming the urothelial epigenome, leading to urothelial-intrinsic remodelling and training of the innate response to subsequent infection.
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/doi: 10.3390/v12090932
