Downregulation of Pannexin-1 attenuates sepsis-induced acute lung injury via activation of the cAMP/PKA pathway.

Sepsis is the leading cause of death in intensive care unit (ICU) and the most expensive condition treated in the US, without a specific therapy yet available. Acute lung injury (ALI) is one of the most significant organ injuries in sepsis, resulting from massive migration of neutrophils to the lung, but the exact mechanism is not known. β2 (CD18) integrin family [consisting of αLβ2 (CD11a/CD18), αMβ2 (CD11b/CD18), αXβ2 (CD11c/CD18) and αDβ2 (CD11d/CD18)] and its counter-receptor on the endothelium, ICAM-1 (CD54), are critical for neutrophil migration, but their role in ALI is not yet delineated. Using a murine model of sepsis induced by cecal ligation and puncture (CLP) surgery, we showed decreased neutrophil levels and attenuated injury in the lung of β2−/− and ICAM-1−/− mice at 12h post-CLP, suggesting the importance of β2 integrins in this process. In addition, we observed decreased neutrophil levels and attenuated injury in the lung of αDβ2−/− mice but not in the lung of αLβ2−/− and αMβ2−/− mice, suggesting that αDβ2 has an orchestrating role in sepsis-induced ALI. In support, we found increased αDβ2 expression levels on neutrophils both in the lung and blood of WT mice as sepsis progressed. RNAseq analysis in neutrophils from blood and lung of WT and αDβ2−/− mice showed that αDβ2 mediates neutrophil migration to the lung through pathways associated with antigen presentation, apoptosis and NOD-like receptor signaling. αDβ2−/− neutrophils had also less Cxcr2, Ltb4r1 and Dhrs9 expression, associated with neutrophil migration and the retinoic acid pathway. Taken together, our results suggest a mechanism for ALI in sepsis in which αDβ2 integrin has a major role and could be a novel target for therapeutic intervention. The Anesthesia Research Distinguished Trailblazer Award, Boston Children's Hospital The William F. Milton Fund, Harvard University

Acute lung injury (ALI) affects an estimated 190,000 persons per year in U.S. intensive care units (ICUs), but little is known about its prevalence in the emergency department (ED). The objective was to describe the prevalence of ALI among mechanically ventilated adult nontrauma patients in the ED. The hypothesis was that the prevalence of ALI in adult ED patients would be low. This was a retrospective cohort study of admitted nontrauma patients presenting to an academic ED. Two trained investigators abstracted data from patient records using a standardized form. The use of mechanical ventilation in the ED was identified in two phases. First, all ED patients were screened for the current procedural terminology (CPT) code for endotracheal intubation (CPT 31500) from January 1, 2003, to December 31, 2006. Second, each patient record was reviewed to verify the use of mechanical ventilation. ALI was defined in accordance with a modified version of the American-European Consensus Conference criteria as: 1) hypoxemia defined as PaO(2) /FiO(2) ratio ≤300 mm Hg on all arterial blood gases (ABGs) in the ED and the first 24 hours of admission, 2) the presence of bilateral infiltrates on chest radiograph, and 3) the absence of left atrial hypertension. Data are presented in absolute numbers and percentages. Interobserver agreement was evaluated using the kappa statistic. Of the 552 patients who received mechanical ventilation in the ED and were subsequently admitted, a total of 134 (24.3%, 95% confidence interval [CI] = 20.8% to 28.0%) met hypoxemia criteria. Of these, 34 had evidence of left atrial hypertension, 52 did not have chest radiograph findings consistent with ALI, and two did not have a chest radiograph performed; the remaining 46 met ALI criteria. An additional two patients who died in the ED had clinical evidence of ALI. Thus, 48 of 552, or 8.7% (95% CI = 6.6% to 11.3%), met criteria for ALI. The kappa value for determination of ALI was 0.84 (95% CI = 0.54 to 1.0). The prevalence of ALI was nearly 9% in adult nontrauma patients receiving mechanical ventilation in the ED. Further study is required to determine which types of patients present to the ED with ALI, the extent to which lung protective ventilation is used, and the need for ED ventilator management algorithms.

Minocycline attenuates oxidative and inflammatory injury in a intestinal perforation induced septic lung injury model via down-regulating lncRNA MALAT1 expression

Sepsis-induced acute lung injury (ALI) is a severe organ dysfunction characterized by lung inflammation and apoptosis. The mechanisms underlying sepsis-induced ALI remain poorly understood. Here, we determined the effects of sirtuin 4 (SIRT4) on sepsis-induced ALI. Lipopolysaccharide (LPS)-induced injury cell and cecal ligation and puncture (CLP) animal models were established. Overexpression vectors and lentiviral transfections were used to upregulate SIRT4 expression. Lung cell apoptosis, inflammation, and the levels of associated factors were evaluated. Changes in the PI3K/AKT/mTOR and JAK2/STAT3 pathways were measured, and their potential involvement was examined using LY294002 (PI3K inhibitor), 740 Y-P (PI3K agonist), AG490 (JAK2 inhibitor), and coumermycin A1 (JAK2 agonist). Lower SIRT4 expression was observed in LPS-exposed A549 cells and CLP rats. In LPS-induced A549 cells, Sirt4 overexpression enhanced cell viability, resisted apoptosis, restored the expression of apoptosis-associated proteins (HMB1, cleaved CASP3, BAX, and BCL), and reduced the secretion of pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α). In CLP rats, Sirt4 overexpression prolonged survival time, alleviated lung histopathological damage, reduced pulmonary edema, mitigated lung infection, decreased lung apoptosis, and lowered serum levels of inflammatory cytokines. Furthermore, Sirt4 overexpression blocked JAK2/STAT3/AKT/mTOR phosphorylation. 740 Y-P and coumermycin A1 reversed the protective effects of Sirt4 overexpression in LPS-treated A549 cells, resulting in decreased cell viability and increased apoptosis. LY294002 and AG490 enhanced the protective effects of Sirt4 overexpression in LPS-treated A549 cells. SIRT4 alleviates sepsis-induced ALI by inhibiting JAK2/STAT3/PI3K/AKT/mTOR signaling. Upregulating SIRT4 expression may serve as an innovative therapeutic approach for lung injury management in sepsis.

Acute lung injury (ALI) progresses rapidly, is difficult to treat, and has a high fatality rate. The excessive inflammatory response is an important pathological mechanism of ALI. NLRC3 (NLR family CARD domain-containing 3), a non-inflammasome member of the NLR family, has been found that it could negatively regulates various biological pathways associated with inflammatory response, such as NF-κB (nuclear factor kappa B), PI3K (Phosphatidylinositol 3′-kinase)-Akt (protein kinase B)-mTOR (mammalian target of the rapamycin), and STING (stimulator of interferon genes) pathways, which are responsible for the progression of pulmonary inflammation and participate in regulating the pathological progression of ALI. However, the effects of NLRC3 in sepsis-induced pathological injury of lung tissue remain unclear. In this study, we aimed to investigate the potential effects of NLRC3 in the sepsis-induced ALI. To investigate whether NLRC3 participates in inhibiting the pulmonary inflammatory response of sepsis-induced ALI. Sepsis-induced ALI mice models were established by intrabronchial injection of lipopolysaccharide (LPS) or cecum ligation and puncture (CLP). The lentivirus with overexpression of NLRC3 (LV-NLRC3) and downregulation of NLRC3 (LV-NLRC3-RNAi) were transfected to LPS-induced ALI mice. The expression of NLRC3 was upregulated or downregulated in the lung tissue of sepsis-induced ALI mice. Transfection with NLRC3-overexpression lentivirus significantly decreased inflammatory response in the lung of LPS-induced ALI mice in contrast to the control group. By transfection with NLRC3-silencing lentivirus, the inflammatory response in LPS-induced ALI mice was aggravated. Our study provides evidence of the protective effect of NLRC3 in sepsis-induced ALI by inhibiting excessive inflammatory response of the lung tissue. AbbreviationsAcute lung injury: ALI; intensive care units: ICU; lipopolysaccharide: LPS; acute respiratory distress syndrome: ARDS; bronchoalveolar lavage fluid: BALF; nucleotide-binding oligomerization domain-like receptors: NLRs; NLR family CARD domain containing 3: NLRC3; nuclear factor kappa B: NF-κB; tumor necrosis factor receptor-associated factor 6: TRAF6; Phosphatidylinositol 3′-kinase: PI3K; protein kinase B: Akt; mammalian target of the rapamycin: mTOR; stimulator of interferon genes: STING; TANK-binding kinase 1: TBK1; type I interferon: IFN-I; toll-like receptors: TLRs; tumor necrosis factor: TNF; interleukin: IL; NOD-like receptor protein 3: NLRP3; enhanced green fluorescent protein: EGFP; lentivirus: LV; phosphate-buffered saline: PBS; intrabronchial: i.t.; cecum ligation and puncture: CLP; wet/dry: W/D; Real time polymerase chain reaction: RT-PCR; enzyme-linked immunosorbent assay: ELISA; hematoxylin and eosin: H&E; radio immunoprecipitation assay: RIPA; sodium dodecyl sulfate polyacrylamide gel electrophoresis: SDS-PAGE; polyvinylidene fluoride: PVDF; glyceraldehyde 3-phosphate dehydrogenase: GAPDH; bovine serum albumin: BSA; Tris buffered saline containing Tween 20: TBST; standard deviation: SD; one-way analysis of variance: ANOVA; janus kinase 2: JAK2; activators of transcription 3: STAT3; pathogen associated molecular patterns: PAMPs; danger associated molecular patterns: DAMPs.

Introduction: Sepsis can cause acute lung injury (ALI), one of the leading causes of death in critically ill patients. The underlying mechanisms of sepsis-induced acute lung injury include excessive inflammation, oxidative stress, cell apoptosis, pulmonary edema, and lung tissue dysfunction. Recent studies have shown that miRNA-21 (miR-21) plays a vital role in sepsis-induced acute kidney injury. Relatively few studies have focused on the protective effects of ALI. This study aimed to determine the potential role of miR-21 in sepsis-induced ALI. Methods: We performed quantitative real-time polymerase chain reaction in a septic mouse model induced by cecal ligation and puncture (CLP) and found that miR-21 expression was upregulated. We then transfected the miR-21 precursor to upregulate miR-21 expression and miR-21 inhibitor to downregulate miR-21 expression. The sham group was exposed only to the cecum. ALI was induced by CLP, and the pre-miR-21+ALI and anti-miR-21+ALI groups were treated with miR-21 precursor or miR-21 inhibitor in the caudal vein before CLP. Pre-miR-21+ALI+PTEN inhibition (Pre-miR-21+ALI+PI) and anti-miR-21+ALI+PTEN inhibition (Anti-miR-21+ALI+PI) groups were treated with PTEN inhibition into the caudal vein after miR-21 transfection. Inflammatory cytokines, oxidative stress indicators, lung tissue cell apoptosis, oxygenation index (OI), lung wet/dry weight ratio, and lung pathological changes in the lung were observed in each group. Results: Compared with ALI mice, inflammatory response, oxidative stress indicators, lung tissue cell apoptosis, and the degree of lung injury were remarkably alleviated in Pre-miR-21+ALI mice and aggravated in Anti-miR-21+ALI mice. Western blot analysis showed that phosphatase and tensin homolog (PTEN) protein expression was decreased in CLP-treated mics. PTEN protein expression was decreased in the Pre-miR-21+ALI group but increased in the Anti-miR-21+ALI group. Moreover, the effect of miR-21 on anti-inflammatory, anti-oxidative stress, and anti-apoptosis enhanced after PTEN inhibition. Conclusion: This study revealed that miR-21 has a protective effect in sepsis-induced ALI by regulating PTEN in mice.

RETRACTED: Macrophage SAMSN1 protects against sepsis-induced acute lung injury in mice

Objective Heparin-binding protein (HBP) plays an important role in sepsis and is a prognostic biomarker in patients with sepsis, but the role of HBP in the pathogenesis of sepsis-associated acute lung injury (ALI) remains unclear. This study aimed to investigate the role of HBP in sepsis-induced ALI and its underlying molecular mechanisms. Methods The cecal ligation and puncture (CLP) model was used to induce ALI in mice and randomly divided into 4 groups: control group, CLP (rats treated with cecal ligation and puncture), HBP (rats treated with CLP and HBP injection), and HBP + UFH (rats treated with CLP and injection of HBP and unfractionated heparin). Subsequently, HBP expression in rat serum and lung tissues was detected by qRT-PCR, edema and pathological changes in lung tissue by lung wet-to-dry weight ratio (W/D) and HE staining, myeloperoxidase (MPO) and superoxide dismutase (SOD) activities in lung tissues by detection kits. Additionally, ELISA and western blot were applied for the determination of IL-6, TNF-α, and IL-1β expression in rat bronchoalveolar lavage fluid, and iNOS, Arg-1, Mrc1, NF-κBp65, IKKα, IκBα, and p-IκBα expression in lung tissues. Results The expression levels of HBP in serum and lung tissues of rats in the HBP group were significantly increased, the lung tissues were severely injured, accompanied by a significant increase in MPO activity but a significant decrease in SOD activity, and the levels of IL-6, TNF-α, and IL-1β in bronchoalveolar lavage fluid were significantly increased. In addition, the expression levels of iNOS, NF-κB p65, IKKα, and p-IκBα in the lung tissues of rats in the HBP group were significantly increased, while the addition of unfractionated heparin reversed the above results. Conclusion HBP aggravates ALI in septic rats, and its mechanism may be related to the promotion of macrophage M1 polarization and activation of the NF-κB signaling pathway.

Hydrogen sulfide attenuates ferroptosis and stimulates autophagy by blocking mTOR signaling in sepsis-induced acute lung injury

To investigate whether silence information regulator 1 (SIRT1) could regulate nuclear factor E2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) signaling pathway and its role in acute lung injury (ALI) in sepsis rats. Twenty-four male Sprague-Dawley (SD) rats were randomly divided into sham operation group (Sham group), cecal ligation and puncture (CLP) induced sepsis group (CLP group), sepsis+SIRT1 specific agonist group (CLP+SRT1720 group,10 mg/kg SRT1720 was intraperitoneally injected 2 hours before CLP), sepsis+SIRT1 specific inhibitor group (CLP+EX527 group, 10 mg/kg EX527 was intraperitoneally injected 2 hours before CLP), with 6 rats in each group. The rats were killed 24 hours after modeling and their lung tissues were taken for pathological score (Smith score), superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), tumor necrosis factor-α (TNF-α), interleukins (IL-6, IL-1β), and SIRT1, Nrf2 and HO-1 mRNA and protein expression were detected. The lung tissue of the CLP group mice was severely damaged, the alveolar interval was widened and a large number of inflammatory cells infiltrated, and there was visible pulmonary capillary hyperemia. The Smith score, the levels of TNF-α, IL-6, IL-1β, MDA and 8-OHdG were significantly increased, the levels of SOD, GSH, SIRT1, Nrf2 and HO-1 were significantly decreased in CLP group. After using SIRT1 specific agonist, the lung injury in CLP+SRT1720 group was significantly alleviated compared with that in CLP group, Smith score and lung tissue TNF-α, IL-6, and IL-1β levels were significantly decreased [Smith score: 2.83±0.75 vs. 5.67±0.52, TNF-α (ng/L): 36.78±5.36 vs. 66.99±5.44, IL-6 (ng/L): 23.97±3.76 vs. 45.70±4.16, IL-1β (ng/L): 16.76±1.39 vs. 39.64±2.59, all P < 0.05], SOD activity and GSH content increased [SOD (kU/g): 115.88±3.31 vs. 101.65±1.09, GSH (μmol/g): 8.42±0.81 vs. 5.74±0.46, both P < 0.05], MDA and 8-OHdG contents decreased [MDA (μmol/g): 5.24±0.33 vs. 9.86±0.66, 8-OHdG (ng/L): 405.76±8.54 vs. 647.12±10.64, both P < 0.05], the mRNA and protein expressions of SIRT1, Nrf2 and HO-1 were increased [SIRT1 mRNA (2-ΔΔCT): 1.49±0.15 vs. 0.64±0.03, Nrf2 mRNA (2-ΔΔCT): 1.19±0.08 vs. 0.84±0.02, HO-1 mRNA (2-ΔΔCT): 1.80±0.41 vs. 0.64±0.11, SIRT1 protein (SIRT1/β-actin): 1.03±0.06 vs. 0.52±0.05, Nrf2 protein (Nrf2/β-actin): 1.14±0.10 vs. 0.63±0.05, HO-1 protein (HO-1/β-actin): 1.01±0.11 vs. 0.73±0.03, all P < 0.05]. The lung injury in CLP+EX527 group was more severe than that in CLP group, Smith score and lung tissue TNF-α, IL-6, IL-1β levels were significantly increased [Smith score: 8.00±0.89 vs. 5.67±0.52, TNF-α (ng/L): 87.15±4.23 vs. 66.99±5.44, IL-6 (ng/L): 66.79±2.93 vs. 45.70±4.16, IL-1β (ng/L): 58.99±2.12 vs. 39.64±2.59, all P < 0.05], SOD activity and GSH content decreased [SOD (kU/g): 72.84±3.85 vs. 101.65±1.09, GSH (μmol/g): 3.30±0.67 vs. 5.74±0.46, both P < 0.05], the contents of MDA and 8-OHdG were increased [MDA (μmol/g): 14.14±0.70 vs. 9.86±0.66, 8-OHdG (ng/L): 927.66±11.47 vs. 647.12±10.64, both P < 0.05], the mRNA and protein expressions of SIRT1, Nrf2 and HO-1 were decreased [SIRT1 mRNA (2-ΔΔCT): 0.40±0.07 vs. 0.64±0.03, Nrf2 mRNA (2-ΔΔCT): 0.48±0.07 vs. 0.84±0.02, HO-1 mRNA (2-ΔΔCT): 0.27±0.14 vs. 0.64±0.11, SIRT1 protein (SIRT1/β-actin): 0.20±0.05 vs. 0.52±0.05, Nrf2 protein (Nrf2/β-actin): 0.45±0.01 vs. 0.63±0.05, HO-1 protein (HO-1/β-actin): 0.36±0.08 vs. 0.73±0.03, all P < 0.05]. In the rat model of ALI induced by sepsis, SIRT1 can regulate the activation of Nrf2/HO-1 signaling pathway, upregulate the expression of downstream antioxidant enzymes, reduce oxidative stress injury, and then alleviate the ALI induced by sepsis in rats.

IntroductionSepsis-induced acute lung injury (ALI) has been reported to have a higher case fatality rate than other causes of ALI. However, differences in the severity of illness in septic vs. non-septic ALI patients might explain this finding.Methods520 patients enrolled in the Improving Care of ALI Patients Study (ICAP) were prospectively characterized as having sepsis or non sepsis-induced ALI. Biologically plausible risk factors for in-hospital death were considered in multiple logistic regression models to evaluate the independent association of sepsis vs. non-sepsis ALI risk factors with mortality.ResultsPatients with sepsis-induced ALI had greater illness severity and organ dysfunction (APACHE II and SOFA scores) at ALI diagnosis and higher crude in-hospital mortality rates compared with non-sepsis ALI patients. Patients with sepsis-induced ALI received similar tidal volumes, but higher levels of positive end expiratory pressure, and had a more positive net fluid balance in the first week after ALI diagnosis. In multivariable analysis, the following variables (odds ratio, 95% confidence interval) were significantly associated with hospital mortality: age (1.04, 1.02 to 1.05), admission to a medical intensive care unit (ICU) (2.76, 1.42 to 5.36), ICU length of stay prior to ALI diagnosis (1.15, 1.03 to 1.29), APACHE II (1.05, 1.02 to 1.08), SOFA at ALI diagnosis (1.17, 1.09 to 1.25), Lung Injury Score (2.33, 1.74 to 3.12) and net fluid balance in liters in the first week after ALI diagnosis (1.06, 1.03 to 1.09). Sepsis did not have a significant, independent association with mortality (1.02, 0.59 to 1.76).ConclusionsGreater severity of illness contributes to the higher case fatality rate observed in sepsis-induced ALI. Sepsis was not independently associated with mortality in our study.

Objective To investigate the effects of penehyclidine hydrochloride (PHCD) pretreatment on β-arrestin-1 expression during sepsis-induced acute lung injury in mice.Methods Thirty female Kunming mice,weighing 18-20 g,were randomly divided into 3 groups (n =10 each):sham operation group (S group),sepsis group (CLP group) and PHCD group.Sepsis was induced by cecal ligation and puncture (CLP).In PHCD group,PHCD 0.45 mg/kg was injected intraperitoneally 1 h before CLP.The equal volume of normal saline was given instead in groups S and CLP.The mice were sacrificed at 12 h after CLP,bronchoalveolar lavage fluid (BALF) was collected for measurement of the total protein concentration,and the lungs were removed for determination of wet/dry lung weight ratio and expression of myosin light chain kinase (MLCK),vascular endothelial cadherin (VE-cad-herin) and β-arrestin-1 in lung tissues.The pathological changes of the lung were scored.Results Compared with group S,the lung injury score,wet/dry lung weight ratio and total protein concentration in BALF were significantly increased,MLCK expression was up-regulated and VE-cadherin expression was down-regulated in groups CLP and PHCD,β-arrestin-1 expression was down-regulated in group CLP and β-arrestin-1 expression was up-regulated in group PHCD (P ＜ 0.05 or 0.01).The lung injury score,wet/dry lung weight ratio,total protein concentration in BALF,and MLCK expression were significantly lower,while the expression of VE-cadherin and β-arrestin-1 was higher in PHCD group than in CLP group (P ＜ 0.05 or 0.01).Conclusion PHCD pretreatment can ameliorate acute lung injury through up-regulating β-arrestin-1 expression and reducing microvascular permeability in septic mice. Key words: Cholinergic antagonists ; Arrestins ; ; Respiratory distress syndrome, adult ; Sepsis

BackgroundInterplay between systemic inflammation and programmed cell death contributes to the pathogenesis of acute lung injury (ALI). cAMP-regulated transcriptional coactivator 1 (CRTC1) has been involved in the normal function of the pulmonary system, but its role in ALI remains unclear.Methods and resultsWe generated a Crtc1 knockout (KO; Crtc1−/−) mouse line. Sepsis-induced ALI was established by cecal ligation and puncture (CLP) for 24 h. The data showed that Ctrc1 KO substantially ameliorated CLP-induced ALI phenotypes, including improved lung structure destruction, reduced pulmonary vascular permeability, diminished levels of proinflammatory cytokines and chemokines, compared with the wildtype mice. Consistently, in lipopolysaccharide (LPS)-treated RAW264.7 cells, Crtc1 knockdown significantly inhibited the expression of inflammatory effectors, including TNF-α, IL-1β, IL-6 and CXCL1, whereas their expressions were significantly enhanced by Crtc1 overexpression. Moreover, both Crtc1 KO in mice and its knockdown in RAW264.7 cells dramatically reduced TUNEL-positive cells and the expression of pro-apoptotic proteins. In contrast, Crtc1 overexpression led to an increase in the pro-apoptotic proteins and LPS-induced TUNEL-positive cells. Mechanically, we found that the phosphorylation of Akt was significantly enhanced by Crtc1 knockout or knockdown, but suppressed by Crtc1 overexpression. Administration of Triciribine, an Akt inhibitor, substantially blocked the protection of Crtc1 knockdown on LPS-induced inflammation and cell death in RAW264.7 cells.ConclusionsOur study demonstrates that CRTC1 contribute to the pathological processes of inflammation and apoptosis in sepsis-induced ALI, and provides mechanistic insights into the molecular function of CRTC1 in the lung. Targeting CRTC1 would be a promising strategy to treat sepsis-induced ALI in clinic.

Ophiopogonin C protects against acute lung injury by fatal sepsis through pyroptosis macrophage.

IntroductionSepsis refers to severe systemic inflammation leading to acute lung injury (ALI) and death. Introducing novel therapies can reduce the mortality in ALI. Osteopontin (OPN), a secretory glycoprotein produced by immune reactive cells, plays a deleterious role in various inflammatory diseases. However, its role in ALI caused by sepsis remains unexplored. We hypothesize that treatment with an OPN-neutralizing antibody (anti-OPN Ab) protects mice against ALI during sepsis.MethodsSepsis was induced in 8-week-old male C57BL/6 mice by cecal ligation and puncture (CLP). Anti-OPN Ab or non-immunized IgG as control, at a dose of 50 μg/mouse, was intravenously injected at the time of CLP. After 20 hours, the expression of OPN and proinflammatory cytokines in tissues and plasma was examined by real-time PCR, Western blot, and ELISA. Plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) and the lung myeloperoxidase (MPO) levels were determined by colorimetric assays. Lung damage and neutrophil infiltrations were determined by histological H&E and Gr-1 staining, respectively. The effect of recombinant mouse OPN (rmOPN) on human neutrophil-like cell (HL-60) migration was performed by Boyden chamber assays and the involvement of intracellular signaling molecules in HL-60 cells was revealed by Western blot.ResultsAfter 20 hours of sepsis, mRNA and protein levels of OPN were significantly induced in lungs, spleen, and plasma. Treatment with an anti-OPN Ab in septic mice significantly reduced the plasma levels of ALT, AST, and LDH, and the proinflammatory cytokines IL-6, IL-1β and the chemokine MIP-2, compared with the vehicle group. Similarly, the lung mRNA and protein expressions of proinflammatory cytokines and chemokine were greatly reduced in anti-OPN Ab-treated animals. The lung histological architecture, MPO and neutrophil infiltration were significantly improved in anti-OPN Ab-treated mice compared with the vehicle animals. Treatment of rmOPN in HL-60 cells significantly increased their migration, in vitro. The neutrophils treated with rmOPN remarkably increased the levels of phospho focal adhesion kinase (pFAK), phospho extracellular signal-regulated kinase (pERK) and phospho p38.ConclusionsOur findings clearly demonstrate the beneficial outcomes of anti-OPN Ab treatment in protecting against ALI, implicating a novel therapeutic strategy in sepsis.