MicroRNA-451 from Human Umbilical Cord-Derived Mesenchymal Stem Cell Exosomes Inhibits Alveolar Macrophage Autophagy via Tuberous Sclerosis Complex 1/Mammalian Target of Rapamycin Pathway to Attenuate Burn-Induced Acute Lung Injury in Rats

Objective Our previous studies established that microRNA(miR)-451 from human umbilical cord mesenchymal stem cell-derived exosomes(hUC-MSC-Exos)alleviates acute lung injury(ALI).This study aims to elucidate the mechanisms by which miR-451 in hUC-MSC-Exos reduces ALI by modulating macrophage autophagy.Methods Exosomes were isolated from hUC-MSCs.Severe burn-induced ALI rat models were treated with hUC-MSC-Exos carrying the miR-451 inhibitor.Hematoxylin-eosin staining evaluated inflammatory injury.Enzyme-linked immunosorbnent assay measured lipopolysaccharide(LPS),tumor necrosis factor-α,and interleukin-1βlevels.qRT-PCR detected miR-451 and tuberous sclerosis complex 1(TSC1)expressions.The regulatory role of miR-451 on TSC1 was determined using a dual-luciferase reporter system.Western blotting determined TSC1 and proteins related to the mammalian target of rapamycin(mTOR)pathway and autophagy.Immunofluorescence analysis was conducted to examine exosomes phagocytosis in alveolar macrophages and autophagy level.Results hUC-MSC-Exos with miR-451 inhibitor reduced burn-induced ALI and promoted macrophage autophagy.MiR-451 could be transferred from hUC-MSCs to alveolar macrophages via exosomes and directly targeted TSC1.Inhibiting miR-451 in hUC-MSC-Exos elevated TSC1 expression and inactivated the mTOR pathway in alveolar macrophages.Silencing TSC1 activated mTOR signaling and inhibited autophagy,while TSC1 knockdown reversed the autophagy from the miR-451 inhibitor-induced.Conclusion miR-451 from hUC-MSC exosomes improves ALI by suppressing alveolar macrophage autophagy through modulation of the TSC1/mTOR pathway,providing a potential therapeutic strategy for ALI.

Dexmedetomidine Alleviates Pulmonary Edema by Upregulating AQP1 and AQP5 Expression in Rats with Acute Lung Injury Induced by Lipopolysaccharide

This study aims to elucidate the mechanisms by which dexmedetomidine alleviates pulmonary edema in rats with acute lung injury induced by lipopolysaccharide （LPS）. Male Wistar rats were randomly divided into five groups： normal saline control （NS） group, receiving intravenous 0.9% normal saline （5 mL/kg）; LPS group, receiving intravenous LPS （10 mg/kg）; small-dose dexmedetomidine （S） group, treated with a small dose of dexmedetomidine （0.5 μg·kg^-1·h^-1）; medium-dose dexmedetomidine （M） group, treated with a medium dose of dexmedetomidine （2.5 μg·kg^-1·h^-1）; high-dose dexmedetomidine （H） group, treated with a high dose of dexmedetomidine （5μg·kg^-1·h^-1）. The rats were sacrificed 6 h after intravenous injection of LPS or NS, and the hmgs were removed for evaluating histological characteristics and determining the lung wet/dry weight ratio （W/D）. The levels of tumor necrosis factor-alpha （TNF-α） and interleukin-1β （IL-1β） in the lung tissues were assessed by enzyme-linked immunosorbent assay （ELISA）. The mRNA and protein expression levels of aquaporin-1 （AQP1） and aquaporin-5 （AQP5） were detected by RT-PCR, immunohistochemistry, and Western blot- ting. The lung tissues from the LPS groups were significantly damaged, which were less pronounced in the H group but not in the small-dose dexmedetomidine group or medium-dose dexmedetomidine group. The W/D and the concentrations of TNF-α and IL-1β in the pulmonary tissues were increased in the LPS group as compared with those in NS group, which were reduced in the H group but not in S group or M group （P〈0.01）. The expression of AQP1 and AQP5 was lower in the LPS group than in the NS group, and significantly increased in the H group but not in the S group or M group （P〈0.01）. Our findings suggest that dexmedetomidine may alleviate pulmonary edema by increasing the expression of AQP-1 and AQP-5.

Therapeutic effects of Caspase-1 inhibitors on acute lung injury in experimental severe acute pancreatitis

AIM： To assess the therapeutic effect of Caspase-1 inhibitors （ICE-I） on acute lung injury （ALI） in experimental severe acute pancreatitis （SAP）. METHODS： Forty-two SD rats were randomly divided into 3 groups： healthy controls （HC, n = 6）; SAP-S group （n = 18）; SAP-ICE-i group （n = 18）. SAP was induced by retrograde infusion of 5% sodium taurocholate into the bile-pancreatic duct. HC rats underwent the same surgical procedures and duct cannulation without sodium taurocholate infusion, in SAP-S group, rats received the first intraperitoneal injection of isotonic saline 2 h after induction of acute pancreatitis and a repeated injection after 12 h. In SAP-ICE-I group, the rats were firstly given ICE inhibitors intraperitoneally 2 h after induction of pancreatitis. As in SAP-S group, the injection was repeated at 12 h. Serum 1L-1β was measured by EUSA. Intrapulmonary expression of Caspase-1, IL-1β and IL-18 mRNA were detected by semi-quantitative RT-PCR. The wet/dry weight ratios and histopathological changes of the lungs were also evaluated. RESULTS： Serum IL-1β levels in SAP-S group were 276.77 ± 44.92 pg/mL at 6 h, 308.99 ± 34.95 pg/mL at 12 h, and 311.60 ± 46.51 pg/mL at 18 h, which were increased significantly （P 〈 0.01, vs HC）. in SAP- ICE-I group, those values were decreased significantly （P 〈 0.01, vs SAP-S）. intrapulmonary expression of Caspase-1, IL-1β and IL-18 mRNA were observed in the HC group, while they were increased significantly in the SAP-S group （P 〈 0.01, vs HC）. The expression of IL-lβ and IL-18 mRNA were decreased significantly in the SAP- ICE-I group （P 〈 0.01, vs SAP-S）, whereas Caspase-1 mRNA expression had no significant difference （P 〉 0.05）. The wet/dry weight ratios of the lungs in the SAP-S group were increased significantly （P 〈 0.05 at 6 h, P 〈 0.01 at 12 h and 18 h, vs HC） and they were decreased significantly in the SAP-ICE-I group （P 〈 0.05, vs SAP-S）.Caspase-1 inhibitors ameliorated the severity of ALl in SAP.CONCLUSION： Caspase-1 activation, and overproduction of IL-1β and IL-18 play an important role in the course of ALI, and Caspase-1 inhibition is effective for the treatment of ALI in experimental SAP.

Calycosin attenuates severe acute pancreatitis-associated acute lung injury by curtailing high mobility group box 1-induced inflammation

BACKGROUND Acute lung injury(ALI)is a common and life-threatening complication of severe acute pancreatitis(SAP).There are currently limited effective treatment options for SAP and associated ALI.Calycosin(Cal),a bioactive constituent extracted from the medicinal herb Radix Astragali exhibits potent anti-inflammatory properties,but its effect on SAP and associated ALI has yet to be determined.AIM To identify the roles of Cal in SAP-ALI and the underlying mechanism.METHODS SAP was induced via two intraperitoneal injections of L-arg(4 g/kg)and Cal(25 or 50 mg/kg)were injected 1 h prior to the first L-arg challenge.Mice were sacrificed 72 h after the induction of SAP and associated ALI was examined histologically and biochemically.An in vitro model of lipopolysaccharide(LPS)-induced ALI was established using A549 cells.Immunofluorescence analysis and western blot were evaluated in cells.Molecular docking analyses were conducted to examine the interaction of Cal with HMGB1.RESULTS Cal treatment substantially reduced the serum amylase levels and alleviated histopathological injury associated with SAP and ALI.Neutrophil infiltration and lung tissue levels of neutrophil mediator myeloperoxidase were reduced in line with protective effects of Cal against ALI in SAP.Cal treatment also attenuated the serum levels and mRNA expression of pro-inflammatory cytokines tumor necrosis factor-α,interleukin-6,IL-1β,HMGB1 and chemokine(CXC motif)ligand 1 in lung tissue.Immunofluorescence and western blot analyses showed that Cal treatment markedly suppressed the expression of HMGB1 and phosphorylated nuclear factor-kappa B(NF-κB)p65 in lung tissues and an in vitro model of LPSinduced ALI in A549 cells suggesting a role for HGMB1 in the pathogenesis of ALI.Furthermore,molecular docking analysis provided evidence for the direct interaction of Cal with HGMB1.CONCLUSION Cal protects mice against L-arg-induced SAP and associated ALI by attenuating local and systemic neutrophil infiltration and inflammatory response via inhibition of HGMB1 and the NF-κB signaling pathway.

Effects of compatibility of Scutellaria baicalensis stems and Polygonum cuspidatum on TRPV1 expression and inflammatory cytokines in rats with acute lung injury

Objective:The protective effect of Scutellaria baicalensis Stems and Polygonum Cuspidatum compatibility on lipopolysaccharide(LPS)-induced acute lung injury(ALI)in rats was studied by observing the expression of TRPV1 and inflammatory cytokines.Methods:48 male SD rats were randomly divided into 6 groups:control group,model group,dexamethasone group(5mg/kg)and Scutellaria baicalensis Stems-Polygonum Cuspidatum(3.5,7 and 14g/kg).The administration group was gavaged for 7 days,and the control group and model group were given the same amount of 0.9%sodium chloride.On the 8th day,except the control group,rats in other groups were injected with 8mg/kg LPS through caudal vein to induce Ali model.Take the rat lung tissue 6 hours after modeling,and calculate the wet/dry weight ratio(W/D)of the rat lung tissue;HE staining to observe the pathological changes of lung tissue;Determine the content of tumor necrosis factor-α(TNF-α)and interleukin-1β(1L-1β)in alveolar lavage fluid(BALF)and the activity of superoxide dismutase(SOD)in serum;Detect the mRNA and protein expression levels of TRPV1 receptor in rat lung tissue.Results:Compared with the model group,Scutellaria baicalensis Stems-Polygonum Cuspidatum can significantly reduce the damage of lung tissue structure and bleeding state,W/D value and TNF-α、IL-1βThe content of TRPV1 decreased,the level of SOD increased,and the mRNA and protein expression of TRPV1 receptor decreased.Conclusion:The combination of Scutellaria baicalensis Stems-Polygonum has a protective effect on acute lung injury in rats,and its mechanism may be related to down-regulating the expression of TRPV1 and inhibiting the levels of TNF-αand IL-1βin inflammatory cells.

Intercellular Adhension Molecule-1 in the Pathogenesis of Heroin-induced Acute Lung Injury in Rats

The expression of intercellular adhesion molecule-1 (ICAM-1) in the pathogenesis of heroin-induced acute lung injury (ALI) in rats was investigated. The model of ALI was established by intravenous injection of heroin into tail vein in rats. Thirty-six rats were randomly divided into heroin-treated groups (1 h, 2 h, 4 h, 6 h and 24 h) and normal control group. Changes in histopathologic morphology and biological markers of ALI were measured. The expression of ICAM-1 in lung tissue was detected by using immunohistochemistry and RT-PCR. The results showed that the W/D ratio and protein contents in BALF of the heroin-treated groups were significantly higher than that of the control group (P<0.01). The histopathological changes in the lung tissue were more obvious in heroin-treated groups. The ICAM-1 protein and mRNA expression in the lung tissue of heroin-treated groups were significantly increased as compared with that of the control group (P<0.01), and correlated with the ALI parameters in a time-dependent manner. Increasing of ICAM-1 expression was involved in the formation of heroin-induced lung injury. Furthermore, the level of expression was positively correlated with the severity of lung injury.

Swine-origin influenza-virus-induced acute lung injury:Novel or classical pathogenesis?

Influenza viruses are common respiratory pathogens in humans and can cause serious infection that leads to the development of pneumonia.Due to their hostrange diversity,genetic and antigenic diversity,and potential to reassort genetically in vivo,influenza A viruses are continual sources of novel influenza strains that lead to the emergence of periodic epidemics and outbreaks in humans.Thus,newly emerging viral diseases are always major threats to public health.In March 2009,a novel influenza virus suddenly emerged and caused a worldwide pandemic.The novel pandemic influenza virus was genetically and antigenically distinct from previous seasonal human influenza A/H1N1 viruses;it was identified to have originated from pigs,and further genetic analysis revealed it as a subtype of A/H1N1,thus later called a swine-origin influenza virus A/H1N1.Since the novel virus emerged,epidemiological surveys and research on experimental animal models have been conducted,and characteristics of the novel influenza virus have been determined but the exact mechanisms of pulmonary pathogenesis remain to be elucidated.In this editorial,we summa-rize and discuss the recent pandemic caused by the novel swine-origin influenza virus A/H1N1 with a focus on the mechanism of pathogenesis to obtain an insight into potential therapeutic strategies.

Expression of triggering receptor-1 in myeloid cells of mice with acute lung injury

BACKGROUND： Myeloid cell （TREM-1） is an important mediator of the signal transduction pathway in inflammatory response. In this study, a mouse model of acute lung injury （ALl） by intraperitoneal injection of lipopolysaccharide （LPS） was established to observe the expression pattern of TREM-1 in lung tissue and the role of TREM-1 in pulmonary inflammatory response to ALl.METHODS： Thirty BALB/C mice were randomly divided into a normal control group （n=6） and an ALl group （n=24）. The model of ALl was made by intraperitonal injection of LPS in dose of 10 mg/ kg. Specimens from peripheral blood and lung tissue were collected 6, 12, 24 and 48 hours after LPS injection. RT-PCR was used to detect TREM-1 mRNA, and ELISA was employed for detection of TREM-1 protein and TNF-a protein, and HE staining was performed for the pathological Smith lung scoring under a light microscope.RESULTS： The expressions of TREM-1 mRNAin lung tissue and blood of the ALl group 6, 12, 24, and 48 hours after injection of LPS were higher than those in the control group. The levels of TREM- 1 protein and the levels of TNF-a protein in lung tissue of the ALl group 6, 12, 24, and 48 hours after LPS injection were higher than those of the control group; the level of TREM-1 protein peaked 12 hours after LPS injection, but it was not significantly correlated with the expression of TREM-1 mRNA （P=0.14）; the TNF-a concentration was positively correlated with TREM-1 levels in lung tissue and with Smith pathological score （r=0.795, P=0.001 ：r=0.499, P=0.034）, but not with the expression of TREM-1 mRNA （P=0.176）.CONCLUSION： The expression of TREM-1 mRNA in lung tissue of mice with ALl is elevated, and the expression of TREM-1 mRNA is related to the level of TNF-a and the severity of inflammatory response to ALl. The expressions of the TREM-1 gene are not consistent with the levels of TREM-1 protein, suggesting a new functional protein involved in immune regulation.

Ubiquitin Reduces Expression of Intercellular Adhesion Molecules and Tumor Necrosis Factor-α in Lung Tissue of Experimental Acute Lung Injury

Background Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) are two important cytokines in inflammatory response, which may induce rolling and adhesion of both leukocytes and lymphocytes, while modulating vascular permeability at the same time. These adhesion molecules usually serve as surrogate markers of activation and injury of vascular endothelial cells. Tumor necrosis factor-α (TNF-α) is a key factor to induce the expression and production of the above cell adhesion molecules. However, it remains to be elucidated whether exogenous ubiquitin exerts any effect on the cytokines in sepsis-induced ALI. Methods Sixty mice were devided randomly into five groups with twelve mice in each group, i.e. CLP group, SHAM group, UB1 group (10 mg/kg), UB2 group (5 mg/kg) and UB3 group(1 mg/kg). Mice of SHAM group underwent sham operation, and other four groups underwent CLP. Six hours after surgery, mice of three UB groups received ubiquitin by caudal vein injection while CLP and SHAM group received vehicle. Seven hours after surgery, blood and lungs of all mice were collected. ICAM-1, VCAM-1 and TNF-α level of 9% lung homogenate and serum TNF-α level were measured by ELISA. Results Pulmonary ICAM-1, VCAM-1 and TNF-α level of three UB groups were lower than CLP and SHAM group, and there were several comparisons with a statistically significant difference. Serum TNF-α level of three UB groups were slightly lower than CLP group, but far higher than SHAM group. Pulmonary ICAM-1 level, VCAM-1 level and serum TNF-α level of UB3 group were lower than UB1 and UB2 group, and there was a significant difference in VCAM-1 between UB3 and UB1 group. Pulmonary TNF-α level of UB3 group was slightly higher than UB1 and UB2 group.

α_1-ANTITRYPSIN ATTENUATES ENDOTOXIN-INDUCED ACUTE LUNG INJURY IN RABBITS

Objective To investigate whether pretreatment with α 1-AT can attenuate acute lung injury (ALI) in rabbits induced with endotoxin. Methods Thirty-two New Zealand rabbits were randomly assigned to four groups(n=8):1.Infusion of endotoxin(Lipopolysaccharide,LPS 500μg/kg)without α 1-AT (group LPS).2.Infusion α 1-AT 120mg/kg at 15min before challenge with LPS(group LAV).3.Infusion of α 1-AT 120mg/kg(group AAT).4 Infusion of saline 4ml/kg as control (group NS).Arterial blood gases,peripheral leukocyte counts and airway pressure were recorded every 1h.Physiologic intrapulmonary shunting (Qs/Qt) was measured every 4h.After 8h the bloods were collected for measurement of plasma concentration and activity of α 1-AT.Then bronchoalveolar lavage fluid (BALF)was collected for measurement of concentrations of total protein (TP),interleukin-8(IL-8),tumor necrosis factor(TNF-α),the activities of elastase-like and α 1-AT,total phospholipids(TPL) and disaturated phosphatidylcholine (DSPC).In addition,the wet-to-dry lung weight ratio(W/D) was measured. Results After infusion of endotoxin,it was observed that PaO 2,peripheral luekocyte counts,total respiratory compliance progressively decreased and P peak and Qs/Qt increased comparing with the baseline values.In contrast to group NS,the increased plasma concentration but reduced activity of α 1-AT was found in group LPS.In the BALF,the activity of α 1-AT,TPL,DSPC/TPL were lower,but the concentrations of albumin,IL-8,TNF-α,and the activity of NE were higher.The ratio of W/D also increased.The pretreatment of α 1-AT attenuated the deterioration of oxygenation,the reduction of compliance and the deterioration of other physiological,biochemical parameters mentioned above. Conclusion Pretreatment with α 1-AT could attenuate endotoxin-induced lung injury in rabbits.Those beneficial effects of α 1-AT might be due in part to the inhibitory effect on neutrophil elastase.

Protective Effect of Curcumin on Endotoxin-induced Acute Lung Injury in Rats

To investigate the protective effect of curcumin on endotoxin-induced acute lung injury in rats, and explore the underlying mechanisms, 24 male Wistar rats were randomly divided into 4 experimental groups： sham-vehicle （S）, sham-curcumin （C）, lipopolysaccharide （LPS）-vehicle （L）, and curcumin-lipopolysaccharide （C-L） groups. The wet/dry （W/D） weight ratio of the lung and bronchoalveolar lavage （BAL） fluid protein content were used as measures of lung injury. Neutrophil recruitment and activation were evaluated by BAL fluid cellularity and myeloperoxidase （MPO） activity in cell-free BAL and lung tissue. The levels of cytokine-induced neutrophil chemoattractant-1 （CINC-1） in lung tissues were measured by ELISA. were observed by using the HE staining. Our results the wet/dry weight ratio and protein content in BALE The histopathological changes of lung tissues showed that lung injury parameters, including were significantly higher in the L group than in the S group （P〈0.01）. In the L group, higher numbers of neutrophils and greater MPO activity in cell-free BAL and lung homogenates were observed when compared with the S group （P〈0.01）. There was a marked increase in CINC-1 levels in lung tissues in response to LPS challenge （P〈0.01, L group vs S group）. Curcumin pretreatment significantly attenuated LPS-induced changes in these indices. LPS caused extensive morphological lung damage, which was also lessened after curcumin pretreatment. All the above-mentioned parameters in the C group were not significantly different from those of the S group. It is concluded that curcumin pretreatment attenuates LPS-induced lung injury in rats. This beneficial effect of curcumin may involves, in part, inhibition of neutrophilic recruitment and activity, possibly through inhibition of lung CINC-1 expression.

The relationship between platelet endothelial cell adhesion molecule-1 and paraquat-induced lung injury in rabbits

BACKGROUND:Platelet endothelial cell adhesion molecule-1(PECAM-1),also known as CD31,is mainly distributed in vascular endothelial cells.Studies have shown that PECAM-1 is a very significant indicator of angiogenesis,and has been used as an indicator for vascular endothelial cells.The present study aimed to explore the relationship between the expression of PECAM-1 and the degree of acute lung injury(ALI) and fibrosis in paraquat(PQ) induced lung injury in rabbits.METHODS:Thirty-six adult New Zealand rabbits were randomly divided into three groups(12rabbits in each group) according to PQ dosage:8 mg/kg(group A),16 mg/kg(group B),and 32 mg/kg(group C).After PQ infusion,the rabbits were monitored for 7 days and then euthanized.The lungs were removed for histological evaluation.Masson staining was used to determine the degree of lung fibrosis(LF),and semi-quantitative immune-histochemistry analysis to determine the expression of PECAM-1.Pearson's product-moment correlation analysis was performed to evaluate the relationship between the expression of PECAM-1 and the extent of lung injuries expressed by ALI score and degree of LF.RESULTS:Rabbits in the three groups showed apparent poisoning.The rabbits survived longer in group A than in groups B and C(6.47±0.99 days vs.6.09±1.04 days vs.4.77±2.04 days)(P<0.05).ALI score was lower in group A than in groups B and C(8.33±1.03 vs.9.83±1.17 vs.11.50±1.38)(P<0.05),and there was statistically significant difference between group B and group C(P=0.03).LF was slighter in group A than in groups B and C(31.09%±2.05%vs.34.37%±1.62%vs.36.54%±0.44%)(P<0.05),and there was statistically significant difference between group B and group C(P=0.026).The PEACAM-1 expression was higher in group A than in groups B and C(20.31%±0.70%vs.19.34%±0.68%vs.18.37%±0.46%)(P<0.05),and there was statistically significant difference between group B and group C(P=0.017).Pearson's correlation analysis showed that the expression of PECAM-1 was negatively correlated to both ALI score(Coe=-0.732,P=0.001)and degree of LF(Coe=-0.779,P<0.001).CONCLUSIONS:The PECAM-1 expression significantly decreases in New Zealand rabbits after PQ poisoning,and the decrease is dose-dependent.The PECAM-1 expression is negatively correlated with ALI score and LF,showing a significant role in the development of lung injuries induced by PQ.

Protective Effect of Genistein on Lipopolysaccharide-induced Acute Lung Injury in Rats

Summary： To investigate the protective effect of genistein on endotoxin-induced acute lung injury in rats, and explore the underlying mechanisms, 32 male Sprague-Dawley rats were randomly divided into 4 experimental groups： saline control, genistein alone, lipopolysaccaride alone, and genistein pretreatment. Each treatment group consisted of eight animals. Animals were observed for 6 h after LPS challenge, and the wet/dry （W/D） weight ratio of the lung and bronchoalveolar lavage fluid （BALF） protein content were used as a measure of lung injury. Neutrophil recruitment and activation were evaluated by BALF cellularity and myeloperoxidase （MP（）） activity. RT-PCR analysis was performed in lung tissue to assess gene expression of ICAM-1. The histopathological changes were also observed using the HE staining of lung tissue. Our results showed that lung injury parameters, including the wet/dry weight ratio and protein content in BALF, were significantly higher in the LPS alone group than in the saline control group （P〈0.01）. In the LPS alone group, a larger number of neutrophils and greater MPO activity in cell-free BAL and lung homogenates were observed when compared with the saline control group （P〈0.01）. There was a significant increase in lung ICAM-1 mRNA in response to LPS challenge （P〈0. 01, group L versus group S）. Genistein pretreatment significantly attenuated LPS-induced changes in these indices. LPS caused extensive lung damage, which was also lessened after genistein pretreatment. All above-mentioned parameters in the genistein alone group were not significantly different from those of the saline control group. It is concluded that genistein pretreatment attenuated LPS-induced lung injury in rats. This beneficial effect of genistein may involves, in part, an inhibition of neutrophilic recruitment and activity, possibly through an inhibition of lung ICAM-1 expression.

Glycolysis and acute lung injury:A review

Acute lung injury is featured as diffuse pulmonary edema and persistent hypoxemia caused by lung or systemic injury.It is believed that these pathological changes are associated with damage to the alveolar epithelium and vascular endothelium,recruitment of inflammatory cells,and inflammatory factor storms.In recent years,the metabolic reprogramming of lung parenchymal cells and immune cells,particularly alterations in glycolysis,has been found to occur in acute lung injury.Inhibition of glycolysis can reduce the severity of acute lung injury.Thus,this review focuses on the interconnection between acute lung injury and glycolysis and the mechanisms of interaction,which may bring hope for the treatment of acute lung injury.

槲皮素预处理ALI大鼠肺组织损伤、炎症/氧化应激反应、铁死亡及Nrf2/HO-1信号通路激活情况观察

目的观察槲皮素灌胃预处理的LPS诱导急性肺损伤(ALI)大鼠肺组织损伤、炎症反应、氧化应激反应、铁死亡及Nrf2/HO-1信号通路激活情况,以探讨槲皮素对ALI的预防作用及机制。方法24只SD大鼠分为槲皮素低、中、高剂量组和阳性对照组(地塞米松)、模型组、正常对照组。槲皮素低、中、高剂量组以25、50、100 mg/kg槲皮素灌胃,1次/天,连续7 d;槲皮素灌胃处理的第4天在大鼠气管内滴注5 mg/kg LPS;阳性对照组以地塞米松1.04 mg/kg灌胃,其余处理同槲皮素组;模型组以生理盐水灌胃,1次/天,连续7天,其余处理同槲皮素组;正常对照组以生理盐水连续灌胃7 d。末次灌注给药后,观察各组肺组织损伤(肺功能及肺组织病理改变、纤维组织阳性表达率、肺泡上皮细胞凋亡率)、炎症反应(肺泡灌洗液TNF-α、IL-6、IL-1β)、氧化应激反应(肺泡灌洗液SOD、GSH、MDA,肺组织ROS)、铁死亡(Fe^(2+)水平)及Nrf2/HO-1信号通路激活[肺组织核因子红细胞2相关因子2(Nfr2)、血红素加氧酶1(HO-1)、超氧化物歧化酶2(SOD2)、过氧化氢酶(CAT)蛋白]情况。结果与正常对照组比较,模型组PaCO_(2)水平升高,PaO_(2)、SaO_(2)水平降低(P均<0.01);肺组织可见肺泡上皮细胞变性坏死,纤维组织阳性表达率高;肺泡上皮细胞凋亡率高;肺泡灌洗液中TNF-α、IL-6、IL-1β水平均升高,SOD、GSH水平降低,MDA水平升高,肺组织ROS表达水平升高,肺泡灌洗液中Fe^(2+)水平升高(P均<0.05)。与模型组相比,槲皮素中、高剂量组和阳性对照组中PaCO_(2)均降低(P均<0.05),槲皮素高剂量组PaO_(2)和SaO_(2)水平升高(P均<0.05);槲皮素高剂量组与阳性对照组肺组织炎性浸润与纤维增生明显减少,肺泡恢复正常生理结构;槲皮素低、中、高剂量组和阳性对照组肺纤维组织阳性表达率均下降(P均<0.05),其中槲皮素高剂量组肺纤维组织阳性表达率最低;槲皮素低、中、高剂量组和阳性对照组肺泡上皮细胞凋亡率均降低(P均<0.01);槲皮素低、中、高剂量组和阳性对照组肺泡灌洗液中TNF-α、IL-6、IL-1β水平均降低、SOD、GSH水平升高、MDA水平降低,肺组织ROS表达水平降低(P均<0.01),肺泡灌洗液中Fe^(2+)水平降低。与正常对照组比较,模型组肺组织中CAT、HO-1、Nrf2、SOD2蛋白表达水平低(P均<0.01);与模型组比较,槲皮素中、高剂量组和阳性对照组肺组织中CAT、HO-1、Nrf2、SOD2蛋白表达水平高(P均<0.05)。结论槲皮素灌胃预处理的ALI大鼠肺组织损伤、炎症反应、氧化应激反应、铁死亡情况减轻,Nfr2/HO-1信号通路激活;槲皮素灌胃预处理可预防LPS诱导的大鼠ALI,可能通过抑制炎症反应、氧化应激反应及铁死亡而起作用;槲皮素可能通过上调Nfr2/HO-1信号通路而抑制炎症反应、氧化应激反应及铁死亡;50、100 mg/kg槲皮素均对LPS诱导的大鼠ALI起预防作用,以100 mg/kg槲皮素的作用效果更佳。

Endothelial extracellular vesicles induce acute lung injury via follistatin-like protein 1

Cardiopulmonary bypass has been speculated to elicit systemic inflammation to initiate acute lung injury(ALI), including acute respiratory distress syndrome(ARDS), in patients after cardiac surgery. We previously found that post-operative patients showed an increase in endothelial cell-derived extracellular vesicles(eEVs) with components of coagulation and acute inflammatory responses. However, the mechanism underlying the onset of ALI owing to the release of e EVs after cardiopulmonary bypass, remains unclear. Plasma plasminogenactivated inhibitor-1(PAI-1) and eEV levels were measured in patients with cardiopulmonary bypass. Endothelial cells and mice(C57BL/6,Toll-like receptor 4 knockout(TLR4^(-/-))) and inducible nitric oxide synthase knockout(iNOS^(-/-)) were challenged with eEVs isolated from PAI-1-stimulated endothelial cells. Plasma PAI-1 and eEVs were remarkably enhanced after cardiopulmonary bypass. Plasma PAI-1 elevation was positively correlated with the increase in eEVs. The increase in plasma PAI-1 and eEV levels was associated with post-operative ARDS. The eEVs derived from PAI-1-stimulated endothelial cells could recognize TLR4 to stimulate a downstream signaling cascade identified as the Janus kinase 2/3(JAK2/3)-signal transducer and activator of transcription 3(STAT3)-interferon regulatory factor 1(IRF-1)pathway, along with i NOS induction, and cytokine/chemokine production in vascular endothelial cells and C57BL/6 mice, ultimately contributing to ALI. ALI could be attenuated by JAK2/3 or STAT3 inhibitors(AG490 or S3I-201, respectively), and was relieved in TLR4-/-and iNOS-/-mice. eEVs activate the TLR4/JAK3/STAT3/IRF-1 signaling pathway to induce ALI/ARDS by delivering follistatin-like protein 1(FSTL1), and FSTL1 knockdown in eEVs alleviates eEV-induced ALI/ARDS. Our data thus demonstrate that cardiopulmonary bypass may increase plasma PAI-1 levels to induce FSTL1-enriched eEVs, which target the TLR4-mediated JAK2/3/STAT3/IRF-1 signaling cascade and form a positive feedback loop, leading to ALI/ARDS after cardiac surgery. Our findings provide new insight into the molecular mechanisms and therapeutic targets for ALI/ARDS after cardiac surgery.

Allosteric regulation of Keap1 by 8β-hydroxy-acyclocostunolide for the treatment of acute lung injury

To the Editor:Acute lung injury(ALI)is a debilitating lung disease characterized by pulmonary edema,diffuse alveolar damage,and uncontrolled neutrophil infiltration^(1).Severe cases of ALI can potentially lead to the development of acute respiratory distress syndrome(ARDS),which can lead to impaired respiratory function,multiorgan dysfunction,and an extremely high mortality rate^(2-4).ALI may be caused by various factors,including aspiration,severe pneumonia,sepsis,trauma,fatty embolism,pancreatitis,and blood transfusion^(3).Current clinical approaches to treating ALI/ARDS include mechanical ventilation,extracorporeal membrane oxygenation(ECMO),and other supportive therapies^(5,6).Therefore,ALI/ARDS is an urgent problem that needs to be addressed in the field of respiratory critical care and innovative mechanisms and therapies^(6).

血清LncRNA-MALAT1、Ang-2与重症急性胰腺炎患者并发急性胃肠损伤的相关性研究

目的探讨血清长链非编码RNA-肺腺癌转移相关转录本1(LncRNA-MALAT1)、血管生成素-2(Ang-2)与重症急性胰腺炎(SAP)患者并发急性胃肠损伤(AGI)的相关性。方法选取2021年1月—2023年1月苏州大学附属苏州市第九人民医院重症医学科收治的轻症急性胰腺炎(AP)患者78例为轻症AP组、中度AP患者78例为中度AP组、SAP患者145例为SAP组,根据是否并发AGI将SAP患者分为AGI亚组83例和非AGI亚组62例。采用实时荧光定量PCR检测血清LncRNA-MALAT1水平,酶联免疫吸附法检测血清Ang-2水平;多因素Logistic回归分析SAP患者并发AGI的影响因素;受试者工作特征(ROC)曲线评价血清LncRNA-MALAT1、Ang-2水平对SAP患者并发AGI的预测价值。结果轻症AP组、中度AP组、SAP组血清LncRNA-MALAT1、Ang-2水平依次升高(F/P=659.197/<0.001、682.682/<0.001);145例SAP患者AGI发生率为57.24%(83/145),AGI亚组SAP患者多器官功能障碍综合征(MODS)比例、急性生理和慢性健康评估Ⅱ(APACHEⅡ)评分、ICU停留时间及血清D-乳酸、LncRNA-MALAT1、Ang-2水平高于非AGI亚组(χ^(2)/t/P=19.273/<0.001、5.052/<0.001、5.308/<0.001、4.085/<0.001、6.864/<0.001、6.824/<0.001);多因素Logistic回归结果示,MODS、APACHEⅡ评分高、D-乳酸高、LncRNA-MALAT1高、Ang-2高为SAP患者并发AGI的独立危险因素[OR(95%CI)=4.496(1.335~15.138)、1.331(1.142~1.551)、1.070(1.020~1.123)、1.101(1.055~1.148)、1.571(1.239~1.994)];血清LncRNA-MALAT1、Ang-2水平及二者联合预测SAP患者并发AGI的AUC分别为0.790、0.785、0.895,二者联合的AUC大于血清LncRNA-MALAT1、Ang-2水平单独预测(Z/P=3.143/0.002、3.650/<0.001)。结论血清LncRNA-MALAT1、Ang-2水平升高与SAP患者并发AGI独立相关,血清LncRNA-MALAT1联合Ang-2水平预测SAP患者并发AGI的价值较高。