Plasminogen activator inhibitor-type I gene deficient mice show reduced influx of neutrophils in ventilator-induced lung injury

Exposure to concentrated ambient PM2.5 (CAPM) induces intestinal disturbance via inflammation and alternation of gut microbiome

Air pollution causes a great disease burden worldwide. Recent evidences suggested that PM_2.5 contributes to intestinal disease. The objective of present study was to investigate the influence of ambient PM_2.5 on intestinal tissue and microbiome via whole-body inhalation exposure. The results showed that high levels and prolonged periods exposure to concentrated ambient PM_2.5 (CAPM) could destroy the mucous layer of the colon, and significantly alter the mRNA expression of tight junction (Occludin and ZO-1) and inflammation-related (IL-6, IL-10 and IL-1β) genes in the colon, comparing with exposure to the filtered air (FA). The composition of intestinal microbiome at the phylum and genus levels also varied along with the exposure time and PM_2.5 levels. At the phylum level, Bacteroidetes was greatly decreased, while Proteobacteria was increased after exposure to CAPM, comparing with exposure to FA. At the genus level, Clostridium XlVa, Akkermansia and Acetatifactor, were significantly elevated exposure to CAPM, comparing with exposure to FA. Our results also indicated that high levels and prolonged periods exposure to CAPM altered metabolic functional pathways. The correlation analysis showed that the intestinal inflammation was related to the alteration of gut microbiome induced by CAPM exposure, which may be a potential mechanism that elucidates PM_2.5-induced intestinal diseases. These results extend our knowledge on the toxicology and health effects of ambient PM_2.5.

Mining the key genes for ventilator-induced lung injury using co-expression network analysis

Mechanical ventilation is extensively adopted in general anesthesia and respiratory failure management, but it can also induce ventilator-induced lung injury (VILI). Therefore, it is of great urgency to explore the mechanisms involved in the VILI pathogenesis, which might contribute to its future prevention and treatment. Four microarray datasets from the GEO database were selected in our investigation, and were subjected to the Weighted Gene Co-Expression Network Analysis (WGCNA) to identify the VILI-correlated gene modules. The limma package in R software was used to identify the differentially expressed genes (DEGs) between the VILI and control groups. WGCNA was constructed by merging the GSE9314, GSE9368, GSE11434 and GSE11662 datasets. A total of 49 co-expression network modules were determined as associated with VILI. The intersected genes between hub genes screened from DEGs for VILI and those identified using WGCNA were as follows: Tlr2, Hmox1, Serpine1, Mmp9, Il6, Il1b, Ptgs2, Fos and Atf3, which were determined to be key genes for VILI. Those key genes were validated by GSE86229 and quantitative PCR (qPCR) experiment to have significantly statistical difference in their expression between the VILI and control groups. In a nutshell, nine key genes with expression differences in VILI were screened by WGCNA by integrating multiple datasets.

Plasma Cold-Inducible RNA-Binding Protein Predicts Lung Dysfunction After Cardiovascular Surgery Following Cardiopulmonary Bypass: A Prospective Observational Study

Background

Cold-inducible RNA-binding protein (CIRP) has been identified as an inflammatory mediator that exerts its function in inflammatory diseases. However, the roles of CIRP in patients who received cardiovascular surgery necessitating cardiopulmonary bypass (CPB) are still unknown. The aim of this study was to examine CIRP levels and attempt to evaluate whether CIRP could serve as a predictor for lung dysfunction after cardiovascular surgery.

Material/Methods

Plasma CIRP levels were detected by ELISA in 31 patients who received cardiovascular surgery at different time points. Selective inflammatory cytokines (TNF-α, IL-6, IL-10, and TLR4) and mediators (Ang II, PAI-1, and soluble E-selectin) were also detected. Selective laboratory and clinical parameters were recorded at scheduled time points.

Results

Compared with pre-operation levels, CIRP levels significantly increased 6 h after cardiovascular surgery with CPB. Multiple linear regression analysis showed that the length of CPB time contributed to CIRP production (P=0.013). Furthermore, CIRP was associated with Ang II (r=0.438, P=0.016), PAI-1 (r=0.485, P=0.006), and soluble E-selectin (r=0.470, P=0.008), which partly reflected lung injuries. Multiple linear regression analysis showed that CIRP levels were independently associated with PaO₂/FiO₂ ratios (P=0.021).

Conclusions

The length of CPB time contributed to the upregulation of CIRP in patients who received cardiovascular surgery with CPB. CIRP levels could serve as a biomarker to predict the onset of lung injury induced by cardiovascular surgery.

Effects of Zinc Finger Protein A20 on Lipopolysaccharide (LPS)-Induced Pulmonary Inflammation/Anti-Inflammatory Mediators in an Acute Lung Injury/Acute Respiratory Distress Syndrome Rat Model

Background

The aim of this study was to investigate the effects of zinc finger protein A20 on lipopolysaccharide (LPS)-induced pulmonary inflammation/anti-inflammatory mediators in an acute lung injury/acute respiratory distress syndrome (ALI/ARDS) rat model.

Material/Methods

Forty-eight ALI/ARDS rats were selected and assigned into normal saline (NS) (injected with NS), LPS (injected with LPS), LPS-C1 (injected with pEGFP-C1, NS and LPS), and A20 groups (injected with pEGFP-C1-A20, NS, and LPS). The wet/dry (W/D) ratio of rat lung tissues and total protein concentration and the number of neutrophils in bronchoalveolar lavage fluid (BALF) were detected. Enzyme-linked immunosorbent assay (ELISA) and qRT-PCR were applied to detect the protein and mRNA expressions of A20, IL-10, and TNF-α, respectively. Western blotting was employed to detect the protein expressions of A20, nuclear factor-kappa B (NF-κB) p65 and NF-κB p-P65 in rat lung tissues.

Results

Compared with the NS group, the W/D ratio of rat lung tissues and total protein concentration and the number of neutrophils in BALF in the other 3 groups increased significantly. The protein and mRNA expressions of A20, IL-10, and TNF-α were significantly higher in the LPS group than in the NS group. The protein and mRNA expressions of A20 and IL-10 were significantly up-regulated and the expression of TNF-α, NF-κB p65, and NF-κB p-P65 was significantly down-regulated in rats injected with A20 compared to those in the LPS group.

Conclusions

The study provided evidence that zinc finger protein A20 can alleviate pulmonary inflammation by inhibiting TNF-α, NF-κB p65, and NF-κB p-P65 expressions and promoting IL-10 expression.

Plasminogen activator inhibitor-1 does not contribute to the pulmonary pathology induced by acute exposure to ozone

Expression of plasminogen activator inhibitor (PAI)-1, the major physiological inhibitor of fibrinolysis, is increased in the lung following inhalation of ozone (O₃), a gaseous air pollutant. PAI-1 regulates expression of interleukin (IL)-6, keratinocyte chemoattractant (KC), and macrophage inflammatory protein (MIP)-2, which are cytokines that promote lung injury, pulmonary inflammation, and/or airway hyperresponsiveness following acute exposure to O₃ Given these observations, we hypothesized that PAI-1 contributes to the severity of the aforementioned sequelae by regulating expression of IL-6, KC, and MIP-2 following acute exposure to O₃ To test our hypothesis, wild-type mice and mice genetically deficient in PAI-1 (PAI-1-deficient mice) were acutely exposed to either filtered room air or O₃ (2 ppm) for 3 h. Four and/or twenty-four hours following cessation of exposure, indices of lung injury [bronchoalveolar lavage fluid (BALF) protein and epithelial cells], pulmonary inflammation (BALF IL-6, KC, MIP-2, macrophages, and neutrophils), and airway responsiveness to aerosolized acetyl-β-methylcholine chloride (respiratory system resistance) were measured in wild-type and PAI-1-deficient mice. O₃ significantly increased indices of lung injury, pulmonary inflammation, and airway responsiveness in wild-type and PAI-1-deficient mice. With the exception of MIP-2, which was significantly lower in PAI-1-deficient as compared to wild-type mice 24 h following cessation of exposure to O₃, no other genotype-related differences occurred subsequent to O₃ exposure. Thus, following acute exposure to O₃, PAI-1 neither regulates pulmonary expression of IL-6 and KC nor functionally contributes to any of the pulmonary pathological sequelae that arise from the noxious effects of inhaled O₃.

In vivo evidence for an endothelium-dependent mechanism in radiation-induced normal tissue injury

The pathophysiological mechanism involved in side effects of radiation therapy, and especially the role of the endothelium remains unclear. Previous results showed that plasminogen activator inhibitor-type 1 (PAI-1) contributes to radiation-induced intestinal injury and suggested that this role could be driven by an endothelium-dependent mechanism. We investigated whether endothelial-specific PAI-1 deletion could affect radiation-induced intestinal injury. We created a mouse model with a specific deletion of PAI-1 in the endothelium (PAI-1KO^endo) by a Cre-LoxP system. In a model of radiation enteropathy, survival and intestinal radiation injury were followed as well as intestinal gene transcriptional profile and inflammatory cells intestinal infiltration. Irradiated PAI-1KO^endo mice exhibited increased survival, reduced acute enteritis severity and attenuated late fibrosis compared with irradiated PAI-1^flx/flx mice. Double E-cadherin/TUNEL labeling confirmed a reduced epithelial cell apoptosis in irradiated PAI-1KO^endo. High-throughput gene expression combined with bioinformatic analyses revealed a putative involvement of macrophages. We observed a decrease in CD68⁺cells in irradiated intestinal tissues from PAI-1KO^endo mice as well as modifications associated with M1/M2 polarization. This work shows that PAI-1 plays a role in radiation-induced intestinal injury by an endothelium-dependent mechanism and demonstrates in vivo that the endothelium is directly involved in the progression of radiation-induced enteritis.