Dataset Information

Activation of M1 macrophages in sepsis-induced acute kidney injury in response to heparin-binding protein.

ABSTRACT:

Background

In the early stage of sepsis, M1 macrophages result in the production of inflammatory mediators and AKI. Heparin-binding protein (HBP) have been shown to play important roles in sepsis-induced AKI. In this study, we investigate the association of HBP with M1 macrophages in sepsis-induced AKI.

Methods

Male C57BL6 mice were subjected to cecal ligation and puncture (CLP) or sham surgery. Biochemical and histological renal damage was assessed. Macrophage infiltration was assessed by immunohistochemistry. RT-PCR was used to investigate the expression of heparin-binding protein (HBP), the inducible nitric oxide synthase (iNOS) and arginase 1 (Arg-1) mRNAs. Western blots were performed to assay the tissue levels of HBP, tumor necrosis factor alpha (TNF-?) and interleukin-6 (IL-6).

Results

High levels of HBP were obviously detected 24 h after sepsis-induced AKI. Heparin inhibited HBP expression during sepsis-induced AKI. The suppression of HBP expression by heparin injection after the establishment of sepsis-induced AKI resulted in a reduction in renal injury severity accompanied with a significant repression of M1 macrophage activation and expression of TNF-? and IL-6.

Conclusions

HBP plays an important role in the initial inflammatory reaction associated with sepsis-induced AKI, presumably by activating M1 macrophages and suppressing TNF-? and IL-6 secretion.

SUBMITTER: Xing L

PROVIDER: S-EPMC5933766 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Publications

Activation of M1 macrophages in sepsis-induced acute kidney injury in response to heparin-binding protein.

Xing Li L Zhongqian Lu L Chunmei Song S Pingfa Chen C Lei He H Qin Jin J Genhua Mu M Yijun Deng D

PloS one 20180503 5

<h4>Background</h4>In the early stage of sepsis, M1 macrophages result in the production of inflammatory mediators and AKI. Heparin-binding protein (HBP) have been shown to play important roles in sepsis-induced AKI. In this study, we investigate the association of HBP with M1 macrophages in sepsis-induced AKI.<h4>Methods</h4>Male C57BL6 mice were subjected to cecal ligation and puncture (CLP) or sham surgery. Biochemical and histological renal damage was assessed. Macrophage infiltration was as ...[more]

PMID: 29723248

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Project description:To identify mechanisms associated with sepsis-acute kidney injury based on the expression levels of renal injury biomarkers, neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1 in renal biopsies which may allow the identification of sepsis-acute kidney injury patient subtypes.DesignProspective, clinical laboratory study using "warm" human postmortem sepsis-acute kidney injury kidney biopsies.SettingResearch laboratory at university teaching hospital.SubjectsAdult patients who died of sepsis in the ICU and control patients undergoing tumor nephrectomy.Measurements and main resultsReverse transcription quantitative polymerase chain reaction and immunohistochemical staining were used to quantify messenger RNA and protein expression levels of neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 in the kidney of sepsis-acute kidney injury patients and control subjects. Morphometric analysis was used to quantify renal and glomerular neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 protein levels. Neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 messenger RNA and protein levels were increased in kidneys of sepsis-acute kidney injury patients compared with control kidney tissue. Neutrophil gelatinase-associated lipocalin was localized in the distal tubules, collecting ducts, the adventitia of the renal arterioles, and in the glomerular tufts of renal biopsies from sepsis-acute kidney injury patients. In contrast, kidney injury molecule-1 was localized at the brush border of the proximal tubules. There was no correlation between neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 levels. Furthermore, renal neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 levels were not associated with the extent of renal injury, the severity of critical illness, or serum creatinine levels at either ICU admission or day of expiration. By laser microdissecting glomeruli, followed by reverse transcription quantitative polymerase chain reaction, we identified heterogenous glomerular neutrophil gelatinase-associated lipocalin production in the kidney of sepsis-acute kidney injury patients.ConclusionWe found differences in the expression of neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 in patients with the same syndrome "sepsis-acute kidney injury" meaning there is no single pathway leading to sepsis-acute kidney injury. This underscores the beliefs that there are many/different pathophysiological pathways that can cause sepsis-acute kidney injury. Hence, patients with criteria that meet the definitions of both acute kidney injury and sepsis can be divided into subtypes based on pathophysiological features.

Project description:Recent studies have shown that autophagy upregulation can attenuate sepsis-induced acute kidney injury (SAKI). The tumor suppressor p53 has emerged as an autophagy regulator in various forms of acute kidney injury (AKI). Our previous studies showed that p53 acetylation exacerbated hemorrhagic shock-induced AKI and lipopolysaccharide (LPS)-induced endothelial barrier dysfunction. However, the role of p53-regulated autophagy in SAKI has not been examined and requires clarification. In this study, we observed the dynamic changes of autophagy in renal tubular epithelial cells (RTECs) and verified the protective effects of autophagy activation on SAKI. We also examined the changes in the protein expression, intracellular distribution (nuclear and cytoplasmic), and acetylation/deacetylation levels of p53 during SAKI following cecal ligation and puncture (CLP) or LPS treatment in mice and in a LPS-challenged human RTEC cell line (HK-2 cells). After sepsis stimulation, the autophagy levels of RTECs increased temporarily, followed by a sharp decrease. Autophagy inhibition was accompanied by an increased renal tubular injury score. By contrast, autophagy agonists could reduce renal tubular damage following sepsis. Surprisingly, the expression of p53 protein in both the renal cortex and HK-2 cells did not significantly change following sepsis stimulation. However, the translocation of p53 from the nucleus to the cytoplasm increased, and the acetylation of p53 was enhanced. In the mechanistic study, we found that the induction of p53 deacetylation, due to either the resveratrol/quercetin -induced activation of the deacetylase Sirtuin 1 (Sirt1) or the mutation of the acetylated lysine site in p53, promoted RTEC autophagy and alleviated SAKI. In addition, we found that acetylated p53 was easier to bind with Beclin1 and accelerated its ubiquitination-mediated degradation. Our study underscores the importance of deacetylated p53-mediated RTEC autophagy in future SAKI treatments.

Dataset Information

Activation of M1 macrophages in sepsis-induced acute kidney injury in response to heparin-binding protein.

Background

Methods

Results

Conclusions

Publications

Activation of M1 macrophages in sepsis-induced acute kidney injury in response to heparin-binding protein.

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