Targeted degradation of extracellular mitochondrial aspartyl-tRNA synthetase modulates immune responses in bacterial pneumonia
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE260733 | GEO | 2024/06/03
REPOSITORIES: GEO
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Project description:The severity of bacterial pneumonia can be worsened by impaired innate immunity resulting in ineffective pathogen clearance. Here We describe a mitochondrial protein, aspartyl-tRNA synthetase (DARS2), which is released in circulation during bacterial pneumonia in humans and displays intrinsic innate immune properties and cellular repair properties. DARS2 interacts with a bacterial-induced ubiquitin E3 ligase subunit, FBXO24, which targets DARS2 for ubiquitylation and degradation, a process that is inhibited by DARS2 acetylation. During experimental pneumonia, Fbxo24 knockout mice exhibit elevated DARS2 levels with a robust increase in pulmonary cellular and cytokine levels. In silico modeling identified an FBXO24 inhibitory compound with immunostimulatory properties which extended DARS2 lifespan in cells. The results suggest we show a unique biological role for an extracellular, mitochondrially derived enzyme and its molecular control regulated by the ubiquitin apparatus, which may serve as a mechanistic platform to enhance protective host immunity through small molecule discovery.
2024-08-10 | PXD050224 | Pride
Project description:Aspartyl-tRNA synthetase 2 (Dars2) is involved in the regulation of mitochondrial protein synthesis and tissue-specific mitochondrial unfolded protein response (UPRmt). The role of Dars2 in the self-renewal and differentiation of hematopoietic stem cells (HSCs) is unknown. Here we show that knockout (KO) of Dars2 significantly impairs the maintenance of HSCs and progenitor cells (HSPCs) without involving its tRNA synthetase activity. Dars2 KO results in significantly reduced expression of Srsf2/3/6 and impairs multiple events of mRNA alternative splicing (AS). Dars2 directly localizes to Srsf3 labeled spliceosomes in HSPCs and regulates the stability of Srsf3. Dars2-deficient HSPCs exhibit aberrant AS of mTOR and Slc22a17. Dars2 KO greatly suppresses the levels of labile ferrous iron and iron-sulfur cluster containing proteins, which dampens mitochondrial metabolic activity and DNA damage repair pathway in HSPCs. Our study reveals that Dars2 plays an unprecedented role in the iron-sulfur metabolism and maintenance of HSPCs by modulating RNA splicing.
2023-09-26 | PXD045562 | Pride
Project description:Pneumonia is a serious problem worldwide. We recently demonstrated that innate defense mechanisms of the lung are highly inducible against pneumococcal pneumonia. To determine the breadth of protection conferred by stimulation of lung mucosal innate immunity, and to identify cells and signaling pathways activated by this treatment, mice were treated with an aerosolized bacterial lysate, then challenged with lethal doses of bacterial and fungal pathogens. Mice were highly protected against a broad array of Gram-positive, Gram-negative, and Class A bioterror bacterial pathogens, and Aspergillus fumigatus. Protection was associated with rapid pathogen killing within the lungs, and this effect was recapitulated in vitro using a respiratory epithelial cell line. Gene expression analysis of lung tissue showed marked activation of NF-kappa-B, Type I and II interferon, and antifungal Card9-Bcl10-Malt1 pathways. Cytokines were the most strongly induced genes, but the inflammatory cytokines TNF and IL-6 were not required for protection. Lung-expressed antimicrobial peptides were also highly upregulated. Taken together, stimulated innate resistance (StIR) appears to occur through the activation of multiple host defense signaling pathways in lung epithelial cells, inducing rapid pathogen killing, and conferring broad protection against virulent bacterial and fungal pathogens. Augmentation of innate antimicrobial defenses of the lungs might have therapeutic value for protection of patients with neutropenia or impaired adaptive immunity against opportunistic pneumonia, and for defense of immunocompetent subjects against a bioterror threat or epidemic respiratory infection. Keywords: Differential expression, innate immunity, pneumonia, immunocompromised host; lung epithelium, in vitro, MLE-15 cells were treated with sham (PBS), NTHi lysate (100 ug/ml) or EF2505-III (40 ug/ml). 4 unique samples per group. Treated for 2 hours. Hybridized to Illumina Sentrix Mouse-6 v1.1 Beadhips.
2010-06-24 | E-GEOD-13685 | biostudies-arrayexpress
Project description:Pneumonia is a serious problem worldwide. We recently demonstrated that innate defense mechanisms of the lung are highly inducible against pneumococcal pneumonia. To determine the breadth of protection conferred by stimulation of lung mucosal innate immunity, and to identify cells and signaling pathways activated by this treatment, mice were treated with an aerosolized bacterial lysate, then challenged with lethal doses of bacterial and fungal pathogens. Mice were highly protected against a broad array of Gram-positive, Gram-negative, and Class A bioterror bacterial pathogens, and Aspergillus fumigatus. Protection was associated with rapid pathogen killing within the lungs, and this effect was recapitulated in vitro using a respiratory epithelial cell line. Gene expression analysis of lung tissue showed marked activation of NF-kappaB, Type I and II interferon, and antifungal Card9-Bcl10-Malt1 pathways. Cytokines were the most strongly induced genes, but the inflammatory cytokines TNF and IL-6 were not required for protection. Lung-expressed antimicrobial peptides were also highly upregulated. Taken together, stimulated innate resistance (StIR) appears to occur through the activation of multiple host defense signaling pathways in lung epithelial cells, inducing rapid pathogen killing, and conferring broad protection against virulent bacterial and fungal pathogens. Augmentation of innate antimicrobial defenses of the lungs might have therapeutic value for protection of patients with neutropenia or impaired adaptive immunity against opportunistic pneumonia, and for defense of immunocompetent subjects against a bioterror threat or epidemic respiratory infection. Keywords: differential gene expression; time course; innate immunity; pneumonia; immunocompromised host; lung epithelium Gene expression patterns in mouse lung homogenates were analyzed 2h after exposure to aerosolized PBS (Sham treatment), 2h after exposure to aerosolized NTHi lysate or 4h after exposure to aerosolized NTHi lysate. Each group consisted of six mice.
2010-06-24 | E-GEOD-13740 | biostudies-arrayexpress
Project description:Pneumonia is a serious problem worldwide. We recently demonstrated that innate defense mechanisms of the lung are highly inducible against pneumococcal pneumonia. To determine the breadth of protection conferred by stimulation of lung mucosal innate immunity, and to identify cells and signaling pathways activated by this treatment, mice were treated with an aerosolized bacterial lysate, then challenged with lethal doses of bacterial and fungal pathogens. Mice were highly protected against a broad array of Gram-positive, Gram-negative, and Class A bioterror bacterial pathogens, and Aspergillus fumigatus. Protection was associated with rapid pathogen killing within the lungs, and this effect was recapitulated in vitro using a respiratory epithelial cell line. Gene expression analysis of lung tissue showed marked activation of NF-kappaB, Type I and II interferon, and antifungal Card9-Bcl10-Malt1 pathways. Cytokines were the most strongly induced genes, but the inflammatory cytokines TNF and IL-6 were not required for protection. Lung-expressed antimicrobial peptides were also highly upregulated. Taken together, stimulated innate resistance (StIR) appears to occur through the activation of multiple host defense signaling pathways in lung epithelial cells, inducing rapid pathogen killing, and conferring broad protection against virulent bacterial and fungal pathogens. Augmentation of innate antimicrobial defenses of the lungs might have therapeutic value for protection of patients with neutropenia or impaired adaptive immunity against opportunistic pneumonia, and for defense of immunocompetent subjects against a bioterror threat or epidemic respiratory infection. Keywords: differential gene expression; time course; innate immunity; pneumonia; immunocompromised host; lung epithelium
2008-11-26 | GSE13740 | GEO
Project description:Pneumonia is a serious problem worldwide. We recently demonstrated that innate defense mechanisms of the lung are highly inducible against pneumococcal pneumonia. To determine the breadth of protection conferred by stimulation of lung mucosal innate immunity, and to identify cells and signaling pathways activated by this treatment, mice were treated with an aerosolized bacterial lysate, then challenged with lethal doses of bacterial and fungal pathogens. Mice were highly protected against a broad array of Gram-positive, Gram-negative, and Class A bioterror bacterial pathogens, and Aspergillus fumigatus. Protection was associated with rapid pathogen killing within the lungs, and this effect was recapitulated in vitro using a respiratory epithelial cell line. Gene expression analysis of lung tissue showed marked activation of NF-kappa-B, Type I and II interferon, and antifungal Card9-Bcl10-Malt1 pathways. Cytokines were the most strongly induced genes, but the inflammatory cytokines TNF and IL-6 were not required for protection. Lung-expressed antimicrobial peptides were also highly upregulated. Taken together, stimulated innate resistance (StIR) appears to occur through the activation of multiple host defense signaling pathways in lung epithelial cells, inducing rapid pathogen killing, and conferring broad protection against virulent bacterial and fungal pathogens. Augmentation of innate antimicrobial defenses of the lungs might have therapeutic value for protection of patients with neutropenia or impaired adaptive immunity against opportunistic pneumonia, and for defense of immunocompetent subjects against a bioterror threat or epidemic respiratory infection. Keywords: Differential expression, innate immunity, pneumonia, immunocompromised host; lung epithelium, in vitro,
2008-11-21 | GSE13685 | GEO
Project description:Novel therapeutic approaches for addressing pneumonia caused by Streptococcus pneumoniae, which exhibit resistance to standard-of-care antibiotics are greatly needed. One viable approach involves precisely stimulating innate immune defenses within the lungs. Using murine models of pneumococcal pneumonia, prior studies demonstrated that intranasal administration of the Toll-like receptor 5 agonist, flagellin, results in a 100-fold decrease in lung infection compared to sole antibiotic therapy, when used as an adjunct treatment to the antibiotic. To promote the transfer of this immunotherapy to clinics and mitigate unwanted systemic inflammation, this project assessed whether the direct delivery of flagellin to the airways through nebulization stimulates respiratory defenses against bacterial infection. Similarly to intranasal administration, nebulized flagellin induced a transient activation of lung innate immunity. In contrast, inhalation by nebulization resulted in an attenuated activation of systemic immune responses. We conclude that flagellin aerosol therapy represents a secure and promising approach in addressing bacterial pneumonia within the context of antimicrobial resistance.
2024-10-11 | GSE252037 | GEO
Project description:Purpose: Leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation (LBSL) is a rare, slowly progressive white matter disease caused by mutations in the mitochondrial aspartyl-tRNA synthetase (DARS2). While patients show characteristic MRI T2 signal abnormalities throughout the cerebral white matter, brain stem, and spinal cord, clinical symptoms appear quite variable and a multitude of gene variants have been associated with the disease. Here, Dars2 deletion from CamKIIα-expressing cortical and hippocampal neurons results in slowly progressive increases in behavioral activity at 5 months, and culminating by 9 months as severe brain atrophy, behavioral dysfunction, reduced corpus callosum thickness, and microglial morphology indicative of neuroinflammation. Methods: Cortical samples were collected from DARS2-Flox/CamKII-Cre(+) and DARS2-Flox/CamKII-Cre(-) at 14 weeks of age. RNA-seq libraries were prepared using purified RNA isolated from frozen tissue using the RNeasy Mini kit. RNA quality and concentration were assayed using a Fragment Analyzer instrument. RNA-seq libraries were prepared using the TruSeq Stranded mRNA PolyA (Unique Dual Index) kit.. Libraries were sequenced on an Illumina HiSeq 4000 instrument. Samples were taken from N=7 DARS2-Flox/CamKII-Cre(+) and N=6 DARS2-Flox/CamKII-Cre(-) male mice. Conclusions: RNA-seq based gene expression studies performed prior to the presentation of this severe phenotype reveal the upregulation of several pathways involved in immune activation, cytokine production and signaling, and the defense response regulation. Among these transcripts, Cystatin F (Cst7), a protease inhibitor recognized as a marker of neurodegenerative disease and active demyelination, is upregulated over 200-fold in mutant mice and may serve as a key regulator of disease progression.
2020-02-04 | GSE141055 | GEO
Project description:Secondary bacterial pneumonia following influenza infection is a significant cause of mortality worldwide. Upper respiratory tract pneumococcal carriage is important as both determinants of disease and population transmission. The immunological mechanisms that contain pneumococcal carriage are well-studied in mice but remain unclear in humans. Loss of this control of carriage following influenza infection is associated with secondary bacterial pneumonia during seasonal and pandemic outbreaks. We used a human type 6B pneumococcal challenge model to show that carriage acquisition induces early degranulation of resident neutrophils and recruitment of monocytes to the nose. Monocyte function associated with clearance of pneumococcal carriage. Prior nasal infection with live attenuated influenza virus induced inflammation, impaired innate function and altered genome-wide nasal gene responses to pneumococcal carriage. Levels of the cytokine IP-10 promoted by viral infection at the time of pneumococcal encounter was positively associated with bacterial density. These findings provide novel insights in nasal immunity to pneumococcus and viral-bacterial interactions during co-infection.
2018-07-25 | GSE117580 | GEO
Project description:Infectious pneumonias exact an unacceptable mortality burden worldwide. Efforts to protect populations from pneumonia have historically focused on antibiotic development and vaccine-enhanced adaptive immunity. However, we have recently reported that the lungs’ innate defenses can be therapeutically induced by inhalation of a bacterial lysate that protects mice against otherwise lethal pneumonia. Here, we tested in mice the hypothesis that Toll-like receptors (TLRs) are required for this antimicrobial phenomenon, and found that resistance could not be induced in the absence of the TLR signaling adaptor protein MyD88. We then attempted to recapitulate the protection afforded by the bacterial lysate by stimulating the lung epithelium with aerosolized synthetic TLR ligands. While most single or combination treatments yielded no protection, simultaneous treatment with ligands for TLR2/6 and TLR9 conferred robust, synergistic protection against virulent Gram-positive and Gram-negative pathogens. Protection was associated with rapid pathogen killing in the lungs, and pathogen killing could be induced from lung epithelial cells in isolation. Taken together, these data demonstrate the requirement for TLRs in inducible resistance against pneumonia, reveal a remarkable, unanticipated synergistic interaction of TLR2/6 and TLR9, reinforce the emerging evidence supporting the antimicrobial capacity of the lung epithelium, and may provide the basis for a novel clinical therapeutic that can protect patients against pneumonia during periods of peak vulnerability. MLE-15 cells were treated with 20 ul volumes of PBS (sham treatment), ODN2395 (0.4 ug), Pam2CSK4 (0.2 ug) or ODN2395+Pam2CSK4. At least 5 unique samples per group. Treated for 2 hours. Hybridized to Illumina Sentrix MouseRef-8 v2 Beadhips.
2011-01-27 | E-GEOD-26864 | biostudies-arrayexpress