Development Of Acute Lung Injury Research Articles

Ameliorative effects of silymarin on HCl-induced acute lung injury in rats; role of the Nrf-2/HO-1 pathway.

Objective(s):Aspiration is a common cause of acute lung injury (ALI), which lacks an effective treatment. Inflammation and oxidative stress play key roles in ALI development. Silymarin is an active extract of Silybum marianum plant seeds (milk thistle). Silymarin has potent anti-inflammatory and antioxidant effects; however its role in aspiration induced ALI has not been investigated. The aim of this study is to investigate the role of silymarin in the treatment of hydrochloric acid (HCl) aspiration induced ALI and explores its mechanisms of action. Materials and Methods:The study included three groups of rats: Control non-treated group, ALI group (intra-tracheal HCl injected), and silymarin treated ALI group. White blood cells (WBCs) with differential count, oxidative stress parameters, B-cell lymphoma 2 (Bcl-2), transforming growth factor-beta (TGF-β), cyclooxygenase 2 (COX-2), nuclear factor erythroid 2-related factor-2 (Nrf-2), and heme oxygenase-1 (HO-1) were investigated. Lung tissue histopathology and immunohistochemical expression of survivin and proliferating cell nuclear antigen (PCNA) were also examined. Results:The results of the study showed that HCL caused histopathological changes in ALI with leukocytopenia and increased oxidative stress biomarkers. It increased TGF-β, up-regulated mRNA expression of COX-2, Nrf-2, and HO-1 and increased survivin and PCNA but decreased Bcl-2. Silymarin ameliorated the histopathological lung injury with further up-regulation of Nrf-2 and HO-1 mRNA and decreased the inflammatory and fibrotic parameters together with up-regulation of the anti-apoptotic and the proliferation parameters.Conclusion:The protective effect of silymarin against ALI is mediated by Nrf-2/HO-1 pathway with subsequent antioxidant, anti-inflammatory, antiapoptotic, and proliferating activities.

Inhibition Of JNK Phosphorylation By Curcumin Analog C66 Protects LPS-Induced Acute Lung Injury.

BackgroundAcute lung injury (ALI) is characterized by high prevalence and high mortality. Thus far, no effective pharmacological treatment has been made for ALI in clinics. Inflammation is critical to the development of ALI. Curcumin analog C66, having reported as an inhibitor of c-Jun N-terminal kinase (JNK), exhibits anti-inflammatory property both in vitro and in vivo. However, whether C66 is capable of reducing lipopolysaccharide (LPS)-induced ALI through the inhibition of inflammation by targeting JNK remains unknown.MethodsIntratracheal injection of LPS was employed to build a mouse ALI model. H&E staining, wet/dry ratio, immunofluorescence staining, inflammatory cell detection, and inflammatory gene expression were used to evaluate lung injury and lung inflammation. In vitro, LPS was used to induce the expression of inflammatory cytokines both in protein and gene levels.ResultsThe results of our studies showed that the pretreatment with C66 and JNK inhibitor SP600125 was capable of attenuating the LPS-induced ALI by detecting pulmonary edema, pathological changes, total protein concentration, and inflammatory cell number in bronchoalveolar lavage fluid (BALF). Besides, C66 and SP600125 also suppressed LPS-induced inflammatory cytokine expression in BALF, serum, and lung tissue. In vitro, LPS-induced production of TNF-α and IL-6 and gene expression of TNF-α, IL-6, IL-1β, and COX-2 could be inhibited by the pretreatment with C66 and SP600125. It was found that C66 and SP600125 could inhibit LPS-induced phosphorylation of JNK both in vitro and in vivo.ConclusionIn brief, our results suggested that C66 protects LPS-induced ALI through the inhibition of inflammation by targeting the JNK pathway. These findings further confirmed the pivotal role of JNK in ALI and implied that C66 is likely to serve as a potential therapeutic agent for ALI.

Collateral damage: necroptosis in the development of lung injury.

Cell death is increasingly recognized as a driving factor in the development of acute lung injury. Necroptosis, an immunogenic regulated cell death program important in innate immunity, has been implicated in the development of lung injury in a diverse range of conditions. Characterized by lytic cell death and consequent extracellular release of endogenous inflammatory mediators, necroptosis can be both beneficial and deleterious to the host, depending on the context. Here, we review recent investigations linking necroptosis and the development of experimental lung injury. We assess the consequences of necroptosis during bacterial pneumonia, viral infection, sepsis, and sterile injury, highlighting increasing evidence from in vitro studies, animal models, and clinical studies that implicates necroptosis in the pathogenesis of ARDS. Lastly, we highlight current challenges in translating laboratory findings to the bedside.

Clinical Characteristics and Outcomes of Acute Lung Injury Caused by Transcatheter Arterial Chemoembolization for Hepatocellular Carcinoma: A Retrospective Cohort Study from a Single Institution in China

Background Acute lung injury (ALI) is a rare but life-threatening pulmonary complication of transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). The aim of this study was to characterize the common risk factors, clinical features, imaging findings, treatments, and outcomes of acute lung injury caused by TACE. Methods A retrospective study was performed on all TACE-associated ALI cases that were diagnosed at authors' hospital from January 2015 to June 2018. Results The study included 14 ALI cases where the mean age of patients was 60.9 ± 11.7 years (range 41-82 years), with a mean onset time of 2.4 ± 1.6 d after TACE. Of the 14 patients, 8 patients (57.1%) developed acute respiratory distress syndrome (ARDS). 7 patients (50%) had underlying chronic respiratory disease and hepatic arteriovenous fistula was detected in 6 patients (42.6%), both of which were significantly higher than control group (P < 0.05). Dyspnea (92.9%) was the most common symptoms. Pleural effusion (64.3%), diffuse pulmonary infiltration (42.9%), and accumulation of Lipiodol in lung field (42.9%) were frequent radiologic abnormalities. 11 patients (78.6%) achieved remission after treatment, and the 30-day mortality rate was approximately 21.4%. Patient's median survival time after the development of ALI was merely 4.3 months, which was obviously worse than control group (4.3 months vs. 13.5 months, P < 0.05). Conclusion This study illustrates that TACE-associated ALI is a rare pulmonary complication with a high mortality rate. We infer that pulmonary Lipiodol embolization might be one of the main causes of TACE-associated ALI. Thus, HCC patients who are at high risk should be closely evaluated and monitored during TACE to avoid such potentially fatal complication.

Tangeretin attenuates lipopolysaccharide-induced acute lung injury through Notch signaling pathway via suppressing Th17 cell response in mice

Tangeretin, a polymethoxylated flavonoid is abundant in citrus fruits, which has been reported to inhibit inflammation by inhibiting NF-κB activation and proinflammatory cytokines. Notch blockage inhibits Th17 cells response that are involved in the development of acute lung injury (ALI). This study investigated the protective effects of tangeretin on LPS-induced ALI in mice. Male C57BL/6 mice were treated with phosphate-buffered saline (PBS), lipopolysaccharide (LPS), LPS and tangeretin, or LPS and N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT, a Notch signaling inhibitor), which were harvested at 48 h after challenged by LPS. CD4+ T cells were treated with tangeretin or DAPT and harvested after 72 h. Tangeretin notably attenuated pathological changes and decreased the wet to dry weight ratio of the mouse lungs. The total cell and neutrophil counts, tumor necrosis factor (TNF)-α in bronchoalveolar lavage fluid (BALF), myeloperoxidase activity of lung tissue were markedly reduced by tangeretin. The percentage of CD4+IL-17 + T cells in the lungs and the concentration of interleukin (IL)-17 and IL-22 in BALF were significantly down-regulated by tangeretin. As with the positive control (DAPT), tangeretin inhibited the activity of the Notch signaling pathway accompanied with the down-regulation of acid-related orphan receptor gamma t and IL-23 receptor expression. This study demonstrated that tangeretin protects against LPS-induced ALI by suppressing Th17 response at least partially, through a Notch-dependent mechanism.

HIF‑1α promotes NLRP3 inflammasome activation in bleomycin‑induced acute lung injury.

The inflammatory response is one of the most important factors in the occurrence and development of acute lung injury (ALI). Hypoxia‑inducible factor‑1α (HIF‑1α) and the NOD‑like receptor 3 (NLRP3) inflammasome have been demonstrated to serve an important role in the pathogenesis of ALI. The objective of the present study was to investigate whether HIF‑1α could regulate activation of the NLRP3 inflammasome and its potential function and specific mechanism in bleomycin (BLM)‑induced ALI. Activation of the NLRP3 inflammasome and secretion of IL‑1β were detected following silencing of HIF‑1α or NF‑κB, respectively, in BLM‑treated A549 and RLE‑6TN cells. The results demonstrated that the NLRP3 inflammasome could be activated after BLM treatment. HIF‑1α and NF‑κB expression significantly increased in the BLM group. The levels of NF‑κB‑ and NLRP3 inflammasome‑associated proteins, including NLRP3, apoptosis‑associated speck‑like protein containing CARD and caspase‑1, markedly decreased after treating A549 and RLE‑6TN cells with HIF‑1α small interfering RNA. Activation of the NLRP3 inflammasome was also inhibited after silencing NF‑κB. Furthermore, the levels of IL‑1β markedly decreased in the cellular culture supernatants following inhibition of HIF‑1α and NF‑κB. Therefore, the present study indicated that HIF‑1α could modulate the activation of the NLRP3 inflammasome and the secretion of IL‑1β through NF‑κB signaling in BLM‑induced ALI. The current results improve understanding of the mechanism of ALI and may provide new ideas for identifying therapeutic targets of ALI.

Inhibition of miR-221 alleviates LPS-induced acute lung injury via inactivation of SOCS1/NF-κB signaling pathway

ABSTRACT The role of inflammation response has been well documented in the development of acute lung injury (ALI). However, little is known about the functions of miRNAs in the regulation of inflammation in ALI. The aim of this study was to explore the effects of miRNAs in the regulation of inflammation in ALI and to elucidate the biomolecular mechanisms responsible for these effects. The expression profiles of miRNAs in lung tissues from lipopolysaccharide (LPS)-induced ALI mice model were analyzed using a microarray. It was observed that microRNA-221-3p (miR-221) was significantly increased in lung tissues in ALI mice. The inhibition of miR-221 attenuated lung injury including decreased lung W/D weight ratio and lung permeability and survival rates of ALI mice, as well as apoptosis, whereas its agomir-mediated upregulation exacerbated the lung injury. Concomitantly, miR-221 inhibition significantly reduced LPS-induced pulmonary inflammation, while LPS-induced pulmonary inflammation was aggravated by miR-221 upregulation. Of note, suppressor of cytokine signaling-1 (SOCS1), an effective suppressor of the NF-κB signaling pathway, was found to be a direct target of miR-221 in RAW264.7 cells. Overexpression of SOCS1 by pcDNA-SOCS1 plasmids markedly reversed the miR-221 inhibition-mediated inhibitory effects on inflammation and apoptosis in LPS-treated RAW264.7 cells. Finally, it was found that miR-221 inhibition suppressed LPS induced the activation of the NF-κB signaling pathway, as demonstrated by downregulation of phosphorylated-IκBα, p-p65 and upregulation of IκBα, whilst miR-221 overexpression had an opposite result in ALI mice. Our findings demonstrate that inhibition of miR-221 can alleviate LPS-induced inflammation via inactivation of SOCS1/NF-κB signaling pathway in ALI mice.

Reverse-D-4F improves endothelial progenitor cell function and attenuates LPS-induced acute lung injury

BackgroundPatients with acute lung injury (ALI) have increased levels of pro-inflammatory mediators, which impair endothelial progenitor cell (EPC) function. Increasing the number of EPC and alleviating EPC dysfunction induced by pro-inflammatory mediators play important roles in suppressing ALI development. Because the high density lipoprotein reverse-D-4F (Rev-D4F) improves EPC function, we hypothesized that it might repair lipopolysaccharide (LPS)-induced lung damage by improving EPC numbers and function in an LPS-induced ALI mouse model.MethodsLPS was used to induce ALI in mice, and then the mice received intraperitoneal injections of Rev-D4F. Immunohistochemical staining, flow cytometry, MTT, transwell, and western blotting were used to assess the effect of Rev-D4F on repairment of lung impairment, and improvement of EPC numbers and function, as well as the signaling pathways involved.ResultsRev-D4F inhibits LPS-induced pulmonary edema and decreases plasma levels of the pro-inflammatory mediators TNF-α and ET-1 in ALI mice. Rev-D4F inhibited infiltration of red and white blood cells into the interstitial space, reduced lung injury-induced inflammation, and restored injured pulmonary capillary endothelial cells. In addition, Rev-D4F increased numbers of circulating EPC, stimulated EPC differentiation, and improved EPC function impaired by LPS. Rev-D4F also acted via a PI3-kinase-dependent mechanism to restore levels of phospho-AKT, eNOS, and phospho-eNOS suppressed by LPS.ConclusionsThese findings indicate that Rev-D4F has an important vasculoprotective role in ALI by improving the EPC numbers and functions, and Rev-D4F reverses LPS-induced EPC dysfuncion partially through PI3K/AKT/eNOS signaling pathway.

Ablation of endothelial Pfkfb3 protects mice from acute lung injury in LPS-induced endotoxemia

Acute lung injury (ALI) is one of the leading causes of death in sepsis. Endothelial inflammation and dysfunction play a prominent role in development of ALI. Glycolysis is the predominant bioenergetic pathway for endothelial cells (ECs). However, the role of EC glycolysis in ALI of sepsis remains unclear. Here we show that both the expression and activity of PFKFB3, a key glycolytic activator, were markedly increased in lipopolysaccharide (LPS)-treated human pulmonary arterial ECs (HPAECs) in vitro and in lung ECs of mice challenged with LPS in vivo. PFKFB3 knockdown significantly reduced LPS-enhanced glycolysis in HPAECs. Compared with LPS-challenged wild-type mice, endothelial-specific Pfkfb3 knockout (Pfkfb3ΔVEC) mice exhibited reduced endothelium permeability, lower pulmonary edema, and higher survival rate. This was accompanied by decreased expression of intracellular adhesion molecule-1 (Icam-1) and vascular cell adhesion molecule 1 (Vcam-1), as well as decreased neutrophil and macrophage infiltration to the lung. Consistently, PFKFB3 silencing or PFKFB3 inhibition in HPAECs and human pulmonary microvascular ECs (HPMVECs) significantly downregulated LPS-induced expression of ICAM-1 and VCAM-1, and monocyte adhesion to human pulmonary ECs. In contrast, adenovirus-mediated PFKFB3 overexpression upregulated ICAM-1 and VCAM-1 expression in HPAECs. Mechanistically, PFKFB3 silencing suppressed LPS-induced nuclear translocation of nuclear factor κB (NF-κB)-p65, and NF-κB inhibitors abrogated PFKFB3-induced expression of ICAM-1 and VCAM-1. Finally, administration of the PFKFB3 inhibitor 3PO also reduced the inflammatory response of vascular endothelium and protected mice from LPS-induced ALI. Overall, these findings suggest that targeting PFKFB3-mediated EC glycolysis is an efficient therapeutic strategy for ALI in sepsis.

Aquaporin 4 Blockade Attenuates Acute Lung Injury Through Inhibition of Th17 Cell Proliferation in Mice

Acute lung injury (ALI) is a syndrome characterized by damage to the alveolar-capillary wall, pulmonary edema and recruitment of inflammatory cells. Previous studies have indicated that aquaporin 4 (AQP4) plays a key role in brain edema formation and resolution. However, the role of AQP4 in the development and progression of ALI is not clear and needs to be resolved. In our current study, mouse ALI was induced by intratracheal instillation of lipopolysaccharide (LPS) at a concentration of 30mg/kg. For the inhibition of AQP4, 200mg/kg of TGN-020 (Sigma, USA) was administered intraperitoneally every 6h starting at 30min before intratracheal instillation of LPS. The results of the present work indicate, for the first time, that mice treated with the AQP4 inhibitor TGN-020 had attenuated LPS-induced lung injury, reduced proinflammatory cytokine release (including IL-1α, IL-1β, IL-6, TNF-α, IL-23, and IL-17A), and an improved survival rate. Additionally, we found that the attenuated lung injury scores, increased survival rate, and decreased BALF total protein concentration in TGN-020-treated mice were all abrogated by rIL-17A administration. Furthermore, TGN-020 treatment downregulated the phosphorylation of PI3K and Akt, increased the expression of SOCS3, and decreased the expression of p-STAT3 and RORγt. In conclusion, inhibition of AQP4 by TGN-020 has a detectable protective effect against lung tissue injury induced by LPS, and this effect is associated with inhibition of IL-17A through the downregulation of the PI3K/Akt signaling pathway and upregulation of SOCS3 protein.

Contributing factors in the development of acute lung injury in a murine double hit model.

Blunt chest (thoracic) trauma (TxT) is known to contribute to the development of secondary pulmonary complications. Of these, acute lung injury (ALI) is common especially in multiply injured patients and might not only be due to the direct trauma itself, but seems to be caused by ongoing and multifactorial inflammatory changes. Nevertheless, the exact mechanisms and contributing factors of the development of ALI following blunt chest trauma are still elusive. 60 CL57BL/6N mice sustained either blunt chest trauma combined with laparotomy without further interventions or a double hit (DH) including TxT and cecal ligation puncture (CLP) after 24h to induce ALI. Animals were killed either 6 or 24h after the second procedure. Pulmonary expression of inflammatory mediators cxcl1, cxcl5, IL-1β and IL-6, neutrophil infiltration and lung tissue damage using the Lung Injury Score (LIS) were determined. Next to a moderate increase in other inflammatory mediators, a significant increase in CXCL1, neutrophil infiltration and lung injury was observed early after TxT, which returned to baseline levels after 24h. DH induced significantly increased gene expression of cxcl1, cxcl5, IL-1β and IL-6 after 6h, which was followed by the postponed significant increase in the protein expression after 24h compared to controls. Neutrophil infiltration was significantly enhanced 24h after DH compared to all other groups, and exerted a slight decline after 24h. LIS has shown a significant increase after both 6 and 24h compared to both control groups as well the late TxT group. Early observed lung injury with moderate inflammatory changes after blunt chest trauma recovered quickly, and therefore, may be caused by mechanical lung injury. In contrast, lung injury in the ALI group did not undergo recovery and is closely associated with significant changes of inflammatory mediators. This model may be used for further examinations of contributing factors and therapeutic strategies to prevent ALI.

Effects of glycyrrhizin on lipopolysaccharide-induced acute lung injury in a mouse model.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are serious clinical disease entities characterized by inflammatory pulmonary edema, which lead to acute hypoxic respiratory failure through various etiologies. According to the studies to date, ALI/ARDS has been recognized as a form of multiorgan failure related to overactive immune response, and overproduction of proinflammatory cytokines released from activated inflammatory cells are considered to play a key role in the development of ALI. Glycyrrhizin (GL) is an extractive component derived from Glycyrrhiza glabra (licorice), which has recently been reported to have various pharmacological effects like anti-inflammatory, anti-tumor, hepato-protective, and anti-viral activities. Nevertheless, the therapeutic effect of GL in ALI is still unclear. The aim of this study was to investigate therapeutic effects of GL on lipopolysaccharide (LPS)-induced ALI in a mouse model and to elucidate explicable mechanisms involved. A total of 36 BALB/c mice (6-week-old, 27.7±1.9-gram body weight) were randomly divided into 3 groups: the control group (normal saline was administered intravenously, n=10), the LPS group (LPS 50 mg/kg was intraperitoneally administered, n=13), and the LPS + GL group (GL was administered intravenously immediately and 12 hours after LPS injection, n=13). Mice were sacrificed after 24 hours, and bronchoalveolar lavage fluid (BALF) was collected for the estimation of protein content, inflammatory cell counts, proinflammatory cytokines, myeloperoxidase (MPO) activity, and expressions of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and nuclear factor kappa B (NF-κB). Then, the lungs were excised for molecular target, histopathological, and immunohistochemical examinations. Compared to the LPS group, GL significantly decreased protein content, inflammatory cell counts, tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), IL-6, MPO activity, and expressions of COX-2, iNOS, and NF-κB in the LPS + GL group. GL attenuated migration and infiltration of inflammatory cells, showing a marked decrease in CD 11b-positive cells (26.77%±0.83% vs. 41.77%±0.81% vs. 23.23%±1.92%, P<0.05) as well as CXCR4-/CXCR1-positive cells (CXCR4: 37.23%±1.00% vs. 59.37%±2.37% vs. 47.45%±4.36%; CXCR1: 32.10%±1.56% vs. 47.03%±1.99% vs. 21.70%±6.50%; all P<0.05) in the control, LPS, and LPS + GL groups. Additionally, immunohistochemistry showed that the expression of Toll-like receptor 4 (TLR-4) was inhibited by GL. The results of this study indicate that GL may have anti-inflammatory and protective effects on LPS-induced ALI in mice. GL inhibited proinflammatory cytokines playing a key role in the initial phase of inflammatory response, which suggests that inhibition of the TLR-4/NF-κB signal pathway would be a possible mechanism underlying the action of GL. Thus, GL can be used as a novel therapeutic strategy for pulmonary inflammation.

Isorhynchophylline exerts anti-inflammatory and anti-oxidative activities in LPS-stimulated murine alveolar macrophages

AimsExcessive inflammatory response and oxidative stress are considered as important pathogenic factors in the development of acute lung injury. Isorhynchophylline (IRN), a tetracyclic oxindole alkaloid isolated from Uncaria rhynchophylla, possesses anti-inflammatory and anti-oxidant activities. Our study aimed to investigate the effects and potential mechanisms of IRN on lipopolysaccharide (LPS)-stimulated murine alveolar macrophage cell lines MH-S and NR8383. Main methodsCCK-8 assay was used to evaluate the cytotoxicity of IRN and LPS. Inflammatory response was assessed by detecting the mRNA expressions and release of tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-6, and plasminogen activator inhibitor-1 (PAI-1) using qRT-PCR and ELISA. The expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 were examined by qRT-PCR and western blot. Oxidative stress was evaluated by detecting malondialdehyde (MDA) level and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT). The changes of the toll like receptor (TLR4)/nuclear factor-kappa B (NF-κB)/nod-like receptor protein 3 (NLRP3) inflammasome pathway was detected by western blot. Key findingsTreatment with LPS or IRN for 24 h showed no cytotoxicity on MH-S and NR8383 cells. IRN pretreatment inhibited LPS-induced production of inflammatory cytokines, expressions of iNOS and COX-2, and oxidative stress in murine alveolar macrophages. Additionally, IRN inhibited LPS-induced activation of TLR4/NF-κB/NLRP3 inflammasome pathway in MH-S cells. Mechanistically, inhibition of TLR4/NF-κB/NLRP3 inflammasome pathway by si-TLR4 suppressed LPS-induced inflammation and oxidative stress in murine alveolar macrophages. SignificanceIRN exerted anti-inflammatory and anti-oxidant effects on LPS-stimulated murine alveolar macrophages via inhibition of the TLR4/NF-κB/NLRP3 inflammasome pathway.

Ischaemic stroke in mice induces lung inflammation but not acute lung injury

Stroke is a major cause of death worldwide and ischemic stroke is the most common subtype accounting for approximately 80% of all cases. Pulmonary complications occur in the first few days to weeks following ischemic stroke and are a major contributor to morbidity and mortality. Acute lung injury (ALI) occurs in up to 30% of patients with subarachnoid haemorrhage but the incidence of ALI after ischemic stroke is unclear. As ischemic stroke is the most common subtype of stroke, it is important to understand the development of ALI following the initial ischemic injury to the brain. Therefore, this study investigated whether focal ischemic stroke causes lung inflammation and ALI in mice. Ischemic stroke caused a significant increase in bronchoalveolar lavage fluid (BALF) macrophages and neutrophils and whole lung tissue proinflammatory IL-1β mRNA expression but this did not translate into histologically evident ALI. Thus, it appears that lung inflammation, but not ALI, occurs after experimental ischemic stroke in mice. This has significant implications for organ donors as the lungs from patient’s dying of ischemic stroke are not severely damaged and could thus be used for transplantation in people awaiting this life-saving therapy.

Penehyclidine hydrochloride exerts protective effects in rats with acute lung injury via the Fas/FasL signaling pathway.

Acute lung injury (ALI) is a critical syndrome that is associated with high morbidity and mortality rates. The activation of the Fas/Fas ligand (FasL) signaling pathway may be an important pathophysiological mechanism during ALI development. Penehyclidine hydrochloride (PHC) has been revealed to exhibit anti-apoptotic properties and may attenuate the observed systemic inflammatory response. The present study was performed to elucidate the molecular mechanism of PHC in the regulation of the Fas/FasL signaling pathway in rats with ALI. An ALI rat model was constructed by inducing blunt chest trauma and hemorrhagic shock (T/HS), with PHC administration prior to or following T/HS. At 6 h following T/HS, blood samples and lung tissues were collected. Western blotting, arterial blood gas analysis, ELISA, hematoxylin and eosin staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining and biochemical indicator analysis were performed to determine the degree of lung injury and the key signaling pathways associated with lung damage. The results indicated that the administration of PHC following T/HS effectively attenuates lung injury by improving pulmonary oxygenation, decreasing histopathological damage, decreasing polymorphonuclear neutrophil count and decreasing Fas, FasL, caspase-8, caspase-3, tumor necrosis factor-α, interleukin (IL)-6 and IL-1β expression. The results indicated that PHC exhibits anti-apoptotic functions and exerts protective effects in ALI rats induced by T/HS, which may be attributed to the inhibition of the Fas/FasL signaling pathway.

Attenuation of interferon regulatory factor 7 activity in local infectious sites of trachea and lung for preventing the development of acute lung injury caused by influenza A virus.

The excessive activation of interferon regulatory factor 7 (IRF7) promotes the development of acute lung injury (ALI) caused by influenza A virus (IAV). However, the deficiency of IRF7 increases the susceptibility to deadly IAV infection in both humans and mice. To test whether the attenuation rather than the abolishment of IRF7 activity in local infectious sites could alleviate IAV-induced ALI, we established IAV-infected mouse model and trachea/lung-tissue culture systems, and designed two IRF7-interfering oligodeoxynucleotides, IRF7-rODN M1 and IRF7-rODN A1, based on the mouse and human consensus sequences of IRF7-binding sites of Ifna/IFNA genes, respectively. In the model mice, we found a close relationship between the IAV-induced ALI and the level/activity of IRF7 in local infectious sites, and also found that the reduced IRF7 level or activity in the lungs of mice treated with IRF7-rODN M1 led to decreased mRNA levels of Ifna genes, reduced neutrophil infiltration in the lungs and prolonged survival of mice. Furthermore, we found that the effects of IRF7-rODN M1 on alleviating IAV-induced ALI could be correlated to the reduced translocation of IRF7, caused by the IRF7-rODN M1, from cytosol to nucleus in IAV-infected cells. These data suggest that the proper attenuation of IRF7 activity in local infectious sites could be a novel approach for treating IAV-induced ALI.

MiR-16 inhibits NLRP3 inflammasome activation by directly targeting TLR4 in acute lung injury

Acute lung injury (ALI) is the leading cause of human death, and it is widely accepted that the runaway inflammation is an important risk for the development of ALI. In the present study, we aimed to investigate the effect of miR-16 on lipopolysaccharide-induced acute lung injury in mice, especially focusing on Toll-like receptor 4 (TLR4) and NF-kB signaling pathway as well as NOD-like receptor protein 3 (NLRP3) inflammasome activation. We established in vivo and in vitro model of ALI using LPS and demonstrated that miR-16 expression was down-regulated in lung tissue as well as A549 cells after 8 h of LPS treatment. Furthermore, when miR-16 levels in lung tissues were up-regulated by miR-16 agomir, it was confirmed that the mRNA and protein levels of NF-κB, NLRP3 inflammasome, and inflammatory factors were decreased by the miR-16 by directly targeting TLR4. We also treated A549 cells with miR-16 mimics and anti-miR-16 to confirm the results. Overall, our experiments showed that miR-16 protects against acute lung injury in mice by regulating the TLR4/ NF-κB pathway and attenuating inflammatory response. This work suggests a potential novel therapeutic approach to combat ALI.

Inhibition of the CD40/CD40L complex protects mice against ALI-induced pancreas degradation.

Acute lung injury (ALI) is a severe complication of transfusion. In a previous study, we saw that inhibition of the CD40/CD40L complex allowed restoration of ALI lesions in an experimental mouse model. This study focused on pancreas-associated injury development during experimental ALI pathogenesis and its limitation through CD40/CD40L complex inhibition. An ALI mouse model was established through intraperitoneal lipopolysaccharide and intravenous anti-major histocompatibility complex class I monoclonal antibody injection. Preemption of lesions was achieved with intravenous injection of neutralizing anti-CD40L monoclonal antibody 30 minutes before the trigger, that is, anti-major histocompatibility complex class I monoclonal antibody administration. Histology and immunoassay analyses were used to evaluate pancreatic lesions. ALI development induced significant degradation of the lungs and pancreas and was associated with pancreatic lesions. Different scores were established showing more severe injury to the pancreas in ALI conditions; however, injury was significantly reduced through CD40/CD40L complex inhibition. This study supports the idea that several organs are exposed during ALI development, and particularly when such experimental ALI aims at mimicking transfusion-associated ALI; nevertheless, preventive treatment inhibiting CD40/CD40L (sCD40L) complex formation provides protection from lung disease as well as disease of other organs.

The role of nicotinamide-adenine dinucleotide phosphate oxidase NOX family in acute lung injury

Acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS), are common critical syndromes. The causes of the syndrome are complex and diverse. The main pathological features are the diffuse inflammatory and protein-rich pulmonary edema caused by destruction of the blood-air barrier. Reactive oxygen species (ROS) mediate oxidative damage by oxidizing bio-macromolecules, including lipids, proteins and nucleic acid. Among many systems producing ROS, nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase-mediated ROS is the main source, and its functional subunit is the transmembrane subunit NOX family. The distribution of NOX family proteins in lung tissue is cell type dependent. NOX-derived ROS is involved in the defense function of lung tissue and related to the occurrence and development of ALI/ARDS. This review mainly describes the cell distribution, activation factors, and its relationship with the occurrence and development of ALI of the NOX family.

Tumor necrosis factor-α, toll-like receptor gene mutation and expression in neonatal bronchopulmonary dysplasia and acute lung injury

With the continuous advancement and improvement of medical technology, the survival rate of preterm infants has gradually increased.Due to the increasing frequency of mechanical ventilation in the neonatal intensive care unit, acute lung injury (ALI), bronchopulmonary dysplasia (BPD) and other common serious complications are inevitable, which seriously affect the quality of life in children.At present, the etiology and pathogenesis of BPD and ALI are not yet clear, but studies had shown that the two had the same genetic factors, such as tumor necrosis factor-α, Toll-like receptor, pulmonary surfactant protein, microRNA and other genes.This paper reviewed the role of tumor necrosis factor-α, Toll-like receptor in the development of BPD and ALI. Key words: Tumor necrosis factor-α; Toll-like receptor; Bronchopulmonary dysplasia; Acute lung injury