Divergent Role of Gamma Interferon in a Murine Model of Pulmonary versus Systemic Klebsiella pneumoniae Infection

ABSTRACT Klebsiella pneumoniae is a leading cause of both community-acquired and nosocomial gram-negative-bacterial pneumonia. A further clinical complication of pulmonary K. pneumoniae infection is dissemination of bacteria from the lung into the peripheral blood, resulting in bacteremia concurrent with the localized pulmonary infection. Here, we report studies detailing the divergent role of gamma interferon (IFN-γ) in pulmonary versus systemic K. pneumoniae infection. Intratracheal inoculation of IFN-γ knockout mice resulted in significantly increased mortality compared to that observed for wild-type infected animals. Increased mortality correlated with a 100-fold increase in pulmonary bacteria within 2 days postinfection and upregulation of lung-associated interleukin-10 (IL-10) mRNA. Interestingly, IFN-γ knockout mice had a twofold reduction in plasma aminospartate transferase activity, indicating diminished liver injury following peripheral blood bacterial dissemination. To study the host response towards blood-borne bacteria in the absence of the ongoing pulmonary infection, intravenous inoculation studies were initiated. IFN-γ knockout mice were no more susceptible to intravenous infection than their wild-type counterparts. The consistent observation in IFN-γ knockout mice was for improved survival correlating with increased clearance of blood- and liver-associated bacteria. Intravenous inoculation resulted in a two- to threefold increase in hepatic IL-10 production 24 and 48 h postinfection. Liver injury was also significantly reduced in IFN-γ knockout mice. These data indicate that IFN-γ secretion is a critical mediator in the resolution of localized gram-negative pulmonary pneumonia. Surprisingly, host responses towards systemic infection with the same bacteria appear to be IFN-γ independent.

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Roles of EXTL2, a member of the EXT family of tumour suppressors, in liver injury and regeneration processes

Biochemical Journal ◽

10.1042/bj20130323 ◽

2013 ◽

Vol 454 (1) ◽

pp. 133-145 ◽

Cited By ~ 13

Author(s):

Satomi Nadanaka ◽

Shoji Kagiyama ◽

Hiroshi Kitagawa

Keyword(s):

Liver Injury ◽

Knockout Mice ◽

Weight Ratio ◽

Hepatocyte Proliferation ◽

Chain Elongation ◽

Wild Type ◽

Ccl4 Administration ◽

Ccl4 Treatment ◽

Regeneration Processes

The gene products of two members of the EXT (exostosin) gene family, EXT1 and EXT2, function together as a polymerase in the biosynthesis of heparan sulfate. EXTL2 (EXT-like 2), one of the three EXTL genes in the human genome that are homologous to EXT1 and EXT2, encodes an N-acetylhexosaminyltransferase. We have demonstrated that EXTL2 terminates chain elongation of GAGs (glycosaminoglycans), and thereby regulates GAG biosynthesis. The abnormal GAG biosynthesis caused by loss of EXTL2 had no effect on normal development or normal adult homoeostasis. Therefore we examined the role of EXTL2 in CCl4 (carbon tetrachloride)-induced liver failure, a model of liver disease. On the fifth day after CCl4 administration, the liver/body weight ratio was significantly smaller for EXTL2-knockout mice than for wild-type mice. Consistent with this observation, hepatocyte proliferation following CCl4 treatment was lower in EXTL2-knockout mice than in wild-type mice. EXTL2-knockout mice experienced less HGF (hepatocyte growth factor)-mediated signalling than wild-type mice specifically because GAG synthesis was altered in these mutant mice. In addition, GAG synthesis in hepatic stellate cells was up-regulated during liver repair in EXTL2-knockout mice. Taken together, the results of the present study indicated that EXTL2-mediated regulation of GAG synthesis was important to the tissue regeneration processes that follow liver injury.

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Intranasal Interleukin-12 Treatment for Protection against Respiratory Infection with the Francisella tularensis Live Vaccine Strain

Infection and Immunity ◽

10.1128/iai.73.4.2306-2311.2005 ◽

2005 ◽

Vol 73 (4) ◽

pp. 2306-2311 ◽

Cited By ~ 67

Author(s):

Nathalie S. Duckett ◽

Sofia Olmos ◽

Douglas M. Durrant ◽

Dennis W. Metzger

Keyword(s):

Respiratory Infection ◽

Francisella Tularensis ◽

Vaccine Strain ◽

Live Vaccine ◽

Interleukin 12 ◽

Live Vaccine Strain ◽

Wild Type ◽

Intranasal Infection ◽

Ifn Γ

ABSTRACT Francisella tularensis is a gram-negative intracellular bacterium that can induce lethal respiratory infection in humans and rodents. However, little is known about the role of innate or adaptive immunity in protection from respiratory tularemia. In the present study, the role of interleukin-12 (IL-12) in inducing protective immunity in the lungs against intranasal infection of mice with the live vaccine strain (LVS) of F. tularensis was investigated. It was found that gamma interferon (IFN-γ) and IL-12 were strictly required for protection, since mice deficient in IFN-γ, IL-12 p35, or IL-12 p40 all succumbed to LVS doses that were sublethal for wild-type mice. Furthermore, exogenous IL-12 treatment 24 h before intranasal infection with a lethal dose of LVS (10,000 CFU) significantly decreased bacterial loads in the lungs, livers, and spleens of wild-type BALB/c and C57BL/6 mice and allowed the animals to survive infection; such protection was not observed in IFN-γ-deficient mice. The resistance induced by IL-12 to LVS infection was still observed in NK cell-deficient beige mice but not in CD8−/− mice. These results demonstrate that exogenous IL-12 delivered intranasally can prevent respiratory tularemia through a mechanism that is at least partially dependent upon the expression of IFN-γ and CD8 T cells.

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Ameliorated course of glucose-6-phosphate isomerase (G6PI)-induced arthritis in IFN-γ receptor knockout mice exposes an arthritis-promoting role of IFN-γ

Journal of Autoimmunity ◽

10.1016/j.jaut.2010.12.006 ◽

2011 ◽

Vol 36 (2) ◽

pp. 161-169 ◽

Cited By ~ 11

Author(s):

Oliver Frey ◽

Tania Mitera ◽

Hilde Kelchtermans ◽

Evelien Schurgers ◽

Thomas Kamradt ◽

...

Keyword(s):

Knockout Mice ◽

Ifn Γ

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Regulation of the cognitive aging process by the transcriptional repressor RP58

10.1101/2021.09.18.460879 ◽

2021 ◽

Author(s):

Tomoko Tanaka ◽

Shinobu Hirai ◽

Hiroyuki Manabe ◽

Kentaro Endo ◽

Hiroko Shimbo ◽

...

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Knockout Mice ◽

Cognitive Aging ◽

Critical Role ◽

Harmful Effect ◽

Transcriptional Repressor ◽

Repair Pathway ◽

Wild Type

Aging involves a decline in physiology which is a natural event in all living organisms. An accumulation of DNA damage contributes to the progression of aging. DNA is continually damaged by exogenous sources and endogenous sources. If the DNA repair pathway operates normally, DNA damage is not life threatening. However, impairments of the DNA repair pathway may result in an accumulation of DNA damage, which has a harmful effect on health and causes an onset of pathology. RP58, a zinc-finger transcriptional repressor, plays a critical role in cerebral cortex formation. Recently, it has been reported that the expression level of RP58 decreases in the aged human cortex. Furthermore, the role of RP58 in DNA damage is inferred by the involvement of DNMT3, which acts as a co-repressor for RP58, in DNA damage. Therefore, RP58 may play a crucial role in the DNA damage associated with aging. In the present study, we investigated the role of RP58 in aging. We used RP58 hetero-knockout and wild-type mice in adolescence, adulthood, or old age. We performed immunohistochemistry to determine whether microglia and DNA damage markers responded to the decline in RP58 levels. Furthermore, we performed an object location test to measure cognitive function, which decline with age. We found that the wild-type mice showed an increase in single-stranded DNA and gamma-H2AX foci. These results indicate an increase in DNA damage or dysfunction of DNA repair mechanisms in the hippocampus as age-related changes. Furthermore, we found that, with advancing age, both the wild-type and hetero-knockout mice showed an impairment of spatial memory for the object and increase in reactive microglia in the hippocampus. However, the RP58 hetero-knockout mice showed these symptoms earlier than the wild-type mice did. These results suggest that a decline in RP58 level may lead to the progression of aging.

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Similarities and differences between IL11 and IL11RA1 knockout mice for lung fibro-inflammation, fertility and craniosynostosis

10.1101/2020.12.10.420695 ◽

2020 ◽

Author(s):

Benjamin Ng ◽

Anissa A. Widjaja ◽

Sivakumar Viswanathan ◽

Jinrui Dong ◽

Sonia P. Chothani ◽

...

Keyword(s):

Knockout Mice ◽

Lung Fibroblasts ◽

Loss Of Function ◽

Wild Type ◽

Reduced Body ◽

Body Weights ◽

Show Evidence ◽

Similarities And Differences ◽

The Impact

AbstractGenetic loss of function (LOF) in IL11RA infers IL11 signaling as important for fertility, fibrosis, inflammation and craniosynostosis. The impact of genetic LOF in IL11 has not been characterized. We generated IL11-knockout (Il11-/-) mice, which are born in normal Mendelian ratios, have normal hematological profiles and are protected from bleomycin-induced lung fibro-inflammation. Noticeably, baseline IL6 levels in the lungs of Il11-/- mice are lower than those of wild-type mice and are not induced by bleomycin damage, placing IL11 upstream of IL6. Lung fibroblasts from Il11-/- mice are resistant to pro-fibrotic stimulation and show evidence of reduced autocrine IL11 activity. Il11-/- female mice are infertile. Unlike Il11ra1-/- mice, Il11-/- mice do not have a craniosynostosis-like phenotype and exhibit mildly reduced body weights. These data highlight similarities and differences between LOF in IL11 or IL11RA while establishing further the role of IL11 signaling in fibrosis and stromal inflammation.

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Human genetic deficiencies reveal the roles of complement in the inflammatory network: Lessons from nature

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0903613106 ◽

2009 ◽

Vol 106 (37) ◽

pp. 15861-15866 ◽

Cited By ~ 93

Author(s):

Knut Tore Lappegård ◽

Dorte Christiansen ◽

Anne Pharo ◽

Ebbe Billmann Thorgersen ◽

Bernt Christian Hellerud ◽

...

Keyword(s):

Inflammatory Responses ◽

Gram Negative Bacteria ◽

Enzyme Release ◽

Experimental Conditions ◽

Gram Negative ◽

Cytokines And Chemokines ◽

Ifn Γ ◽

Inducible Protein ◽

The Complement System

Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, its involvement in human inflammation is incompletely understood. The responses to Gram-negative bacteria were here studied taking advantage of human genetic complement-deficiencies—nature's own knockouts—including a previously undescribed C5 defect. Such deficiencies provide a unique tool for investigating the biological role of proteins. The experimental conditions allowed cross-talk between the different inflammatory pathways using a whole blood model based on the anticoagulant lepirudin, which does not interfere with the complement system. Expression of tissue factor, cell adhesion molecules, and oxidative burst depended highly on C5, mediated through the activation product C5a, whereas granulocyte enzyme release relied mainly on C3 and was C5a-independent. Release of cytokines and chemokines was mediated to varying degrees by complement and CD14; for example, interleukin (IL)-1β and IL-8 were more dependent on complement than IFN-γ and IL-6, which were highly dependent on CD14. IL-1 receptor antagonist (IL-1ra) and IFN-γ inducible protein 10 (IP-10) were fully dependent on CD14 and inversely regulated by complement, that is, complement deficiency and complement inhibition enhanced their release. Granulocyte responses were mainly complement-dependent, whereas monocyte responses were more dependent on CD14. Notably, all responses were abolished by combined neutralization of complement and CD14. The present study provides important insight into the comprehensive role of complement in human inflammatory responses to Gram-negative bacteria.

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Ecto-Nucleotide Triphosphate Diphosphohydrolase-2 (NTPDase2) Deletion Increases Acetaminophen-Induced Hepatotoxicity

International Journal of Molecular Sciences ◽

10.3390/ijms21175998 ◽

2020 ◽

Vol 21 (17) ◽

pp. 5998

Author(s):

Linda Feldbrügge ◽

Katrin Splith ◽

Ines Kämmerer ◽

Sandra Richter ◽

Anna Riddermann ◽

...

Keyword(s):

Liver Injury ◽

Liver Toxicity ◽

Wild Type ◽

Protective Properties ◽

Hepatic Expression ◽

Markers Of Inflammation ◽

Acute Necrotizing ◽

Portal Fibroblast ◽

Portal Fibroblasts

Ecto-nucleotidase triphosphate diphosphohydrolase-2 (NTPDase2) is an ecto-enzyme that is expressed on portal fibroblasts in the liver that modulates P2 receptor signaling by regulating local concentrations of extracellular ATP and ADP. NTPDase2 has protective properties in liver fibrosis and may impact bile duct epithelial turnover. Here, we study the role of NTPDase2 in acute liver injury using an experimental model of acetaminophen (APAP) intoxication in mice with global deletion of NTPDase2. Acute liver toxicity was caused by administration of acetaminophen in wild type (WT) and NTPDase2-deficient (Entpd2 null) mice. The extent of liver injury was compared by histology and serum alanine transaminase (ALT). Markers of inflammation, regeneration and fibrosis were determined by qPCR). We found that Entpd2 expression is significantly upregulated after acetaminophen-induced hepatotoxicity. Entpd2 null mice showed significantly more necrosis and higher serum ALT compared to WT. Hepatic expression of IL-6 and PDGF-B are higher in Entpd2 null mice. Our data suggest inducible and protective roles of portal fibroblast-expressed NTPDase2 in acute necrotizing liver injury. Further studies should investigate the relevance of these purinergic pathways in hepatic periportal and sinusoidal biology as such advances in understanding might provide possible therapeutic targets.

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Disruption of CXCR6 Ameliorates Kidney Inflammation and Fibrosis in Deoxycorticosterone Acetate/Salt Hypertension

Scientific Reports ◽

10.1038/s41598-019-56933-7 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 2

Author(s):

Yuanbo Wu ◽

Changlong An ◽

Xiaogao Jin ◽

Zhaoyong Hu ◽

Yanlin Wang

Keyword(s):

Knockout Mice ◽

Critical Role ◽

Kidney Injury ◽

Wild Type ◽

Salt Treatment ◽

Hypertensive Nephropathy ◽

Deoxycorticosterone Acetate ◽

Kidney Fibrosis ◽

Salt Hypertension

AbstractCirculating cells have a pathogenic role in the development of hypertensive nephropathy. However, how these cells infiltrate into the kidney are not fully elucidated. In this study, we investigated the role of CXCR6 in deoxycorticosterone acetate (DOCA)/salt-induced inflammation and fibrosis of the kidney. Following uninephrectomy, wild-type and CXCR6 knockout mice were treated with DOCA/salt for 3 weeks. Blood pressure was similar between wild-type and CXCR6 knockout mice at baseline and after treatment with DOCA/salt. Wild-type mice develop significant kidney injury, proteinuria, and kidney fibrosis after three weeks of DOCA/salt treatment. CXCR6 deficiency ameliorated kidney injury, proteinuria, and kidney fibrosis following treatment with DOCA/salt. Moreover, CXCR6 deficiency inhibited accumulation of bone marrow–derived fibroblasts and myofibroblasts in the kidney following treatment with DOCA/salt. Furthermore, CXCR6 deficiency markedly reduced the number of macrophages and T cells in the kidney after DOCA/salt treatment. In summary, our results identify a critical role of CXCR6 in the development of inflammation and fibrosis of the kidney in salt-sensitive hypertension.

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Functions of the BamBCDE Lipoproteins Revealed by Bypass Mutations in BamA

Journal of Bacteriology ◽

10.1128/jb.00401-20 ◽

2020 ◽

Vol 202 (21) ◽

Author(s):

Elizabeth M. Hart ◽

Thomas J. Silhavy

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Outer Membrane Proteins ◽

Gram Negative Bacteria ◽

Wild Type ◽

Gram Negative ◽

Bam Complex ◽

Essential Function ◽

The Individual

ABSTRACT The heteropentomeric β-barrel assembly machine (BAM complex) is responsible for folding and inserting a diverse array of β-barrel outer membrane proteins (OMPs) into the outer membrane (OM) of Gram-negative bacteria. The BAM complex contains two essential proteins, the β-barrel OMP BamA and a lipoprotein BamD, whereas the auxiliary lipoproteins BamBCE are individually nonessential. Here, we identify and characterize three bamA mutations, the E-to-K change at position 470 (bamAE470K), the A-to-P change at position 496 (bamAA496P), and the A-to-S change at position 499 (bamAA499S), that suppress the otherwise lethal ΔbamD, ΔbamB ΔbamC ΔbamE, and ΔbamC ΔbamD ΔbamE mutations. The viability of cells lacking different combinations of BAM complex lipoproteins provides the opportunity to examine the role of the individual proteins in OMP assembly. Results show that, in wild-type cells, BamBCE share a redundant function; at least one of these lipoproteins must be present to allow BamD to coordinate productively with BamA. Besides BamA regulation, BamD shares an additional essential function that is redundant with a second function of BamB. Remarkably, bamAE470K suppresses both, allowing the construction of a BAM complex composed solely of BamAE470K that is able to assemble OMPs in the absence of BamBCDE. This work demonstrates that the BAM complex lipoproteins do not participate in the catalytic folding of OMP substrates but rather function to increase the efficiency of the assembly process by coordinating and regulating the assembly of diverse OMP substrates. IMPORTANCE The folding and insertion of β-barrel outer membrane proteins (OMPs) are conserved processes in mitochondria, chloroplasts, and Gram-negative bacteria. In Gram-negative bacteria, OMPs are assembled into the outer membrane (OM) by the heteropentomeric β-barrel assembly machine (BAM complex). In this study, we probe the function of the individual BAM proteins and how they coordinate assembly of a diverse family of OMPs. Furthermore, we identify a gain-of-function bamA mutant capable of assembling OMPs independently of all four other BAM proteins. This work advances our understanding of OMP assembly and sheds light on how this process is distinct in Gram-negative bacteria.

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