Dataset Information

Substance P in polymicrobial sepsis: molecular fingerprint of lung injury in preprotachykinin-A-/- mice.

ABSTRACT: Deletion of mouse preprotachykinin-A (PPTA), which encodes mainly for neuropeptide substance P, has been shown to protect against lung injury and mortality in sepsis. This study explored microarray-based differential gene expression profiles in mouse lung tissue 8 h after inducing microbial sepsis and the effect of PPTA gene deletion. A range of genes differentially expressed (more than two-fold) in microarray analysis was assessed, comparing wild-type and PPTA-knockout septic mice with their respective sham controls, and the data were further validated. Genetic deletion of substance P resulted in a significantly different expression profile of genes involved in inflammation and immunomodulation after the induction of sepsis, compared with wild-type mice. Interestingly, apart from the various proinflammatory mediators, the antiinflammatory cytokine interleukin-1 receptor antagonist gene (IL1RN) was also elevated much more in PPTA(-/-) septic mice. In addition, semiquantitative RT-PCR analysis supported the microarray data. The microarray data imply that the elevated levels of inflammatory gene expression in the early stages of sepsis in PPTA-knockout mice are possibly aimed to resolve the infection without excessive immunosuppression. As scientists are divided over the effects of pro- and antiinflammatory mediators in sepsis, it seems prudent to define the status depending on a complete genome profile. This is the first report exploring pulmonary gene expression profiles using microarray analysis in PPTA-knockout mice subjected to cecal ligation and puncture-induced sepsis and providing additional biological insight into the protection received against lung injury and mortality.

SUBMITTER: Hegde A

PROVIDER: S-EPMC2864813 | biostudies-literature | 2010 May-Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Substance P in polymicrobial sepsis: molecular fingerprint of lung injury in preprotachykinin-A-/- mice.

Hegde Akhil A Tamizhselvi Ramasamy R Manikandan Jayapal J Melendez Alirio J AJ Moochhala Shabbir M SM Bhatia Madhav M

Molecular medicine (Cambridge, Mass.) 20100208 5-6

Deletion of mouse preprotachykinin-A (PPTA), which encodes mainly for neuropeptide substance P, has been shown to protect against lung injury and mortality in sepsis. This study explored microarray-based differential gene expression profiles in mouse lung tissue 8 h after inducing microbial sepsis and the effect of PPTA gene deletion. A range of genes differentially expressed (more than two-fold) in microarray analysis was assessed, comparing wild-type and PPTA-knockout septic mice with their re ...[more]

PMID: 20454520

Similar Datasets

Project description:BackgroundHydrogen sulfide (H2S), produced by the activity of cystathionine-gamma-lyase (CSE), is a key mediator of inflammation in sepsis. The liver sinusoidal endothelial cells (LSECs) are important target and mediator of sepsis. The aim of this study was to investigate the role of CSE-derived H2S on inflammation and LSECs fenestrae in caecal-ligation and puncture (CLP)-induced sepsis using CSE KO mice.MethodsSepsis was induced by CLP, and mice (C57BL/6J, male) were sacrificed after 8 hours. Liver, lung, and blood were collected and processed to measure CSE expression, H2S synthesis, MPO activity, NF-?B p65, ERK1/2, and cytokines/chemokines levels. Diameter, frequency, porosity and gap area of the liver sieve were calculated from scanning electron micrographs of the LSECs.ResultsAn increased CSE expression and H2S synthesizing activity in the liver and lung of wild-type mice following CLP-induced sepsis. This was associated with an increased liver and lung MPO activity, and increased liver and lung and plasma levels of the pro-inflammatory cytokines TNF-?, IL-6, and IL-1?, and the chemokines MCP-1 and MIP-2?. Conversely, CSE KO mice had less liver and lung injury and reduced inflammation following CLP-induced sepsis as evidenced by decreased levels of H2S synthesizing activity, MPO activity, and pro-inflammatory cytokines/chemokines production. Extracellular-regulated kinase (ERK1/2) and nuclear factor-?B p65 (NF-?B) became significantly activated after the CLP in WT mice but not in CSE KO mice. In addition, CLP-induced damage to the LSECs, as indicated by increased defenestration and gaps formation in the LSECs compared to WT sham control. CSE KO mice showed decreased defenestration and gaps formation following sepsis.ConclusionsMice with CSE (an H2S synthesising enzyme) gene deletion are less susceptible to CLP-induced sepsis and associated inflammatory response through ERK1/2-NF-?B p65 pathway as evidenced by reduced inflammation, tissue damage, and LSECs defenestration and gaps formation.

Project description:Background: Acute kidney injury (AKI) portends worse prognosis following sepsis, with limited available interventions. Host iron acquisition by pathogens and systemic inflammatory response are key events in the pathogenesis of sepsis. In sepsis, hepcidin induces iron sequestration to limit iron availability to pathogens. Hepcidin is also known to limit inflammation. Since its role in pathophysiology of sepsis-associated AKI is unknown, we investigated the effect of exogenous hepcidin in endotoxin- and peritonitis-induced pathology and AKI. Methods: C57BL/6 mice were treated with saline or 50-100 µg of hepcidin, pre- and post-LPS injection, or cecal ligation and puncture (CLP, model of peritonitis). Splenectomized mice were challenged with LPS, with and without hepcidin. Mice were euthanized at 24 h after LPS injection and at different time points after CLP. Systemic inflammation and renal injury markers were assessed. Direct effect of hepcidin on renal tubular and endothelial cells was evaluated using endotoxin-induced cytotoxic serum. Role of heavy chain ferritin (H-ferritin) in mediating hepcidin-induced anti-inflammatory effect on LPS stimulated macrophages was evaluated with siRNA studies. Results: Twenty-four hours pretreatment with hepcidin significantly reduced LPS-induced AKI. Hepcidin ameliorated LPS-induced increase in serum TNFα and renal Cox-2, and prevented loss in PGC1α and cytochrome c oxidase activity. This was associated with reduced glomerular injury and preserved mitochondrial structure. Hepcidin did not exert direct protection on the renal parenchymal cells but reduced endotoxin-induced serum cytotoxicity to mitigate renal injury. Splenectomy reduced LPS-induced early inflammation and AKI, independent of hepcidin, indicating the importance of systemic inflammation. Higher splenic H-ferritin in hepcidin-treated animals was associated with reduced splenocytes apoptosis and inflammation. Hepcidin reduced LPS-induced IL-6 secretion in macrophages in H-ferritin dependent manner. Hepcidin significantly reduced CLP-induced AKI, and mortality (20% hepcidin treated vs 80% PBS treated). Importantly hepcidin reduced bacteremia and AKI even when administered after onset of sepsis. Conclusion: We demonstrate a protective role of hepcidin in endotoxin- and peritonitis-induced pathologies and AKI, exerted primarily through its anti-inflammatory effects, and antibacterial property. Macrophage H-ferritin plays an important role in hepcidin-mediated protection against endotoxin-induced inflammation. We uncover a novel prophylactic and therapeutic role of hepcidin in sepsis-associated bacteremia, AKI, and mortality.

Project description:ObjectiveInflammation and oxidative stress contribute to the progression of sepsis-induced acute lung injury (ALI). SAM domain, SH3 domain and nuclear localization signals 1 (SAMSN1) is a signaling adaptor protein, and mainly regulates inflammatory response of various immune cells. The present study generates macrophage-specific SAMSN1-knockout (Samsn1MKO) and SAMSN1-transgenic (Samsn1MTG) mice to investigate its role and mechanism in sepsis-induced ALI.MethodsSamsn1MKO and Samsn1MTG mice were exposed to lipopolysaccharide (LPS) instillation or cecal ligation and puncture (CLP) surgery to induce sepsis-induced ALI. Bone marrow transplantation, cellular depletion and non-invasive adoptive transfer of bone marrow-derived macrophages (BMDMs) were performed to validate the role of macrophage SAMSN1 in sepsis-induced ALI in vivo. Meanwhile, BMDMs were isolated from Samsn1MKO or Samsn1MTG mice to further clarify the role of SAMSN1 in vitro.ResultsMacrophage SAMSN1 expression was increased in response to LPS stimulation, and negatively correlated with LPS-induced ALI in mice. Macrophage SAMSN1 deficiency exacerbated, while macrophage SAMSN1 overexpression ameliorated LPS-induced inflammation, oxidative stress and ALI in mice and in BMDMs. Mechanistically, we found that macrophage SAMSN1 overexpression prevented LPS-induced ALI though activating AMP-activated protein kinase α2 (AMPKα2) in vivo and in vitro. Further studies revealed that SAMSN1 directly bound to growth factor receptor bound protein 2-associated protein 1 (GAB1) to prevent its protein degradation, and subsequently enhanced protein kinase A (PKA)/AMPKα2 activation in a protein tyrosine phosphatase, non-receptor type 11 (PTPN11, also known as SHP2)-dependent manner. Moreover, we observed that macrophage SAMSN1 overexpression diminished CLP-induced ALI in mice.ConclusionOur study documents the protective role of macrophage SAMSN1 against sepsis-induced inflammation, oxidative stress and ALI through activating AMPKα2 in a GAB1/SHP2/PKA pathway, and defines it as a promising biomarker and therapeutic target to treat sepsis-induced ALI.

Project description:BackgroundSex differences in sepsis are underexplored and incompletely understood. Cardiac function in early sepsis is pivotal in determining survival; hyperdynamic left ventricular ejection fraction is associated with higher mortality. Female sex may be cardioprotective, but variable experimental findings have not controlled for hypovolaemia. Sex-specific local cardiac versus peripheral inflammation in causing cardiovascular dysfunction also remain unclear. We therefore examined whether there are sex-specific differences in cardiac function in early sepsis, controlling for volaemic status and sex-specific differences in the peripheral inflammatory response initiated by tumour necrosis factor (TNFα).MethodsWe used an experimental polymicrobial sepsis (faecal slurry) model titrated to minimise hypovolaemia as a confounding factor. We quantified cardiac function (transthoracic cardiac echocardiography) 1 week before, and 18 h after, sepsis. Cardiac injury (troponin I), inflammation and immune cell infiltration (flow cytometry) were quantified in naïve and septic female and male mice 18 h after sepsis. To evaluate the sex-specific influence of TNFα derived from peripheral leukocytes, we repeated the experiments in iRHOM2-/- mice that are unable to shed TNFα exclusively from circulating leucocytes.ResultsSerum troponin I increased to 1.39 ± 0.38 ng mL-1 (from undetectable levels in controls) 18 h after onset of normovolaemic sepsis to a similar extent in both sexes. Stroke volume in male mice increased by 8 µL [(3-13); p = 0.004], compared to individualised pre-sepsis values. By contrast, stroke volume remained at baseline levels in females [mean difference: 4 µL (- 1 to 9)]. Messenger RNA levels of markers for cardiac injury/inflammation after sepsis (real-time polymerase-chain reaction) were elevated in male wild-type mice compared to female wild types (n = 10/sex), with higher cardiac mRNA levels of atrial natriuretic peptide, inflammation (TNFα) and oxidative stress (superoxide dismutase-1), although serum troponin I values were similarly elevated. Flow cytometry analysis of cardiac tissue showed doubling of CD4 + leukocyte infiltration in male mice. Sex-specific cardiac physiologic differences were similar in iRHOM2-/- mice that are unable to shed TNFα exclusively from leucocytes.ConclusionsIn early normovolaemic polymicrobial sepsis, a relative hyperdynamic response develops in male mice. Myocardial stress/injury after early sepsis is limited in females, with less cardiac infiltration of CD4 + leukocytes but independent of shedding of TNFα from peripheral circulating leukocytes.

Dataset Information

Substance P in polymicrobial sepsis: molecular fingerprint of lung injury in preprotachykinin-A-/- mice.

Publications

Substance P in polymicrobial sepsis: molecular fingerprint of lung injury in preprotachykinin-A-/- mice.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets