BML-111 attenuates hemorrhagic shock-induced acute lung injury through inhibiting activation of mitogen-activated protein kinase pathway in rats

Signal Pathways and Markers Involved in Acute Lung Injury Induced by Acute Pancreatitis

Acute pancreatitis (AP) is a common acute abdominal disease with a mortality rate of about 30%. Acute lung injury (ALI) is a common systemic complication of acute pancreatitis, with progressive hypoxemia and respiratory distress as the main manifestations, which can develop into acute respiratory distress syndrome or even multiple organ dysfunction syndrome (MODS) in severe cases, endangering human health. In the model of AP, pathophysiological process of the lung can be summarized as oxidative stress injury, inflammatory factor infiltration, and alveolar cell apoptosis. However, the intrinsic mechanisms underlying AP and how it leads to ALI are not fully understood. In this paper, we summarize recent articles related to AP leading to ALI, including the signal transduction pathways and biomarkers of AP-ALI. There are factors or pathway aggravating ALI, the JAK2-STAT3 signaling pathway, NLRP3/NF-κB pathway, mitogen-activated protein kinase, PKC pathway, neutrophil protease (NP)-LAMC2-neutrophil pathway, and the P2X7 pathway, and there are important transcription factors in the NRF2 signal transduction pathway which could give researchers better understanding of the underlying mechanisms controlling AP and ALI and lay the foundation for finally curing ALI induced by AP.

Ophiopogonin A Alleviates Hemorrhagic Shock-Induced Renal Injury via Induction of Nrf2 Expression

Ophiopogonin, including Ophiopogonin A, B, C, D, is an effective active component of traditional Chinese medicine Ophiopogon japonicus which has a wide range of pharmacological effects such as protecting myocardial ischemia, resisting myocardial infarction, immune regulation, lowering blood glucose, and anti-tumor. However, the functions of ophiopogonin A on hemorrhagic shock (HS)-induced renal injury remain unclear. First, this study constructed an HS rat model and hypoxia HK-2 cell model to assess the effects of ophiopogonin A in vivo and in vitro. In vivo, HE and TUNEL staining show that ophiopogonin A dose-dependently inhibits HS-induced tissue damage and apoptosis. Moreover, ophiopogonin A dose-dependently downregulates the levels of blood urea nitrogen (BUN), creatinine (Cr), KIM-1, NGAL, iNOS, TNF-α, IL-1β, and IL-6 in HS rats kidney tissues, and decreases the number of MPO-positive cells. In vitro, we get similar results that ophiopogonin A dose-dependently improves hypoxia-induced HK-2 cell apoptosis and damage. In addition, ophiopogonin A dose-dependently increases the expression of NF E2-related factor 2 (Nrf2), while knockdown of Nrf2 reverses the functions of ophiopogonin A in vivo and in vitro. Furthermore, ophiopogonin A dose-dependently promotes the phosphorylation of ERK in HS kidney tissues and hypoxia-treated HK-2 cells, suggesting that ophiopogonin A functions via the p-ERK/ERK signaling pathway.

Resolution-Based Therapies: The Potential of Lipoxins to Treat Human Diseases

Inflammation is an a physiological response instead an essential response of the organism to injury and its adequate resolution is essential to restore homeostasis. However, defective resolution can be the precursor of severe forms of chronic inflammation and fibrosis. Nowadays, it is known that an excessive inflammatory response underlies the most prevalent human pathologies worldwide. Therefore, great biomedical research efforts have been driven toward discovering new strategies to promote the resolution of inflammation with fewer side-effects and more specificity than the available anti-inflammatory treatments. In this line, the use of endogenous specialized pro-resolving mediators (SPMs) has gained a prominent interest. Among the different SPMs described, lipoxins stand out as one of the most studied and their deficiency has been widely associated with a wide range of pathologies. In this review, we examined the current knowledge on the therapeutic potential of lipoxins to treat diseases characterized by a severe inflammatory background affecting main physiological systems, paying special attention to the signaling pathways involved. Altogether, we provide an updated overview of the evidence suggesting that increasing endogenously generated lipoxins may emerge as a new therapeutic approach to prevent and treat many of the most prevalent diseases underpinned by an increased inflammatory response.

Emerging role of IL-6 and NLRP3 inflammasome as potential therapeutic targets to combat COVID-19: Role of lncRNAs in cytokine storm modulation

The world has witnessed a high morbidity and mortality caused by SARS-CoV-2, and global death toll is still rising. Exaggerated inflammatory responses are thought to be more responsible for infiltrated immune cells accumulation, organ damage especially lung, dyspnea, and respiratory failure rather than direct effect of viral replication. IL-6 and NLRP3 inflammasome are the major immune components in immune responses stimulation upon pathogen infection. It's noteworthy that the function and expression of these components are remarkably influenced by non-coding RNAs including long non-coding RNAs. Given the potential role of these components in organ damage and pathological manifestations of patients infected with COVID-19, their blockage might be a hopeful and promising treatment strategy. Notably, more study on long non-coding RNAs involved in inflammatory responses could elevate the efficacy of anti-inflammatory therapy. In this review we discuss the potential impact of IL-6 and NLRP3 inflammasome blocker drugs on inflammatory responses, viral clearance, and pathological and clinical manifestations. Collectively, anti-inflammatory strategy might pave the way to diminish clinical and pathological manifestations and thereby discharging patients infected with COVID-19 from hospital.

Effects of the ALX/FPR2 receptors of lipoxin A4 on lung injury induced by fat embolism syndrome in rats

This study was designed to investigate the inflammatory responses in fat embolism syndrome (FES) and the relationship of ALX/FPR2 receptors and lipoxin A₄ (LXA₄) in FES models. In this model, lung injury score, lung tissue wet-to-dry (W/D) ratio and total protein concentration in bronchoalveolar lavage fluid (BALF) were increased compared with those of the control group. Meanwhile, the number of leukocytes and neutrophils was significantly increased in the FES group, as was the myeloperoxidase (MPO) activity and mRNA expression. In addition, the release of TNF-α and IL-1β was increased. Then, we explored whether LXA₄ and ALX/FPR2 were involved in the pathological process of FES. The LXA₄ concentration in the experimental groups was markedly higher than that in the control group. At the same time, the protein and mRNA levels of ALX/FPR2 were upregulated in the rat model of FES. Moreover, rats treated with BML-111, an agonist for the ALX/FPR2 receptor of LXA₄, showed a lower inflammatory response than mice treated with fat alone. However, the role of BML-111 in fat emboli (FE)-induced acute lung injury (ALI) was attenuated by BOC-2, an antagonist of the ALX/FPR2 receptor of LXA₄. Our results demonstrated that the inflammatory response may play an important role in the pathogenesis of FES and that the activation of the ALX/FPR2 receptor for LXA₄ can decrease the inflammatory response and may be a therapeutic target for FE-induced ALI.

BML-111 suppresses TGF-β1-induced lung fibroblast activation in vitro and decreases experimental pulmonary fibrosis in vivo

Pulmonary fibrosis is an aggressive end‑stage disease. Transforming growth factor‑β1 (TGF‑β1) mediates lung fibroblast activation and is essential for the progress of pulmonary fibrosis. BML‑111, a lipoxinA4 (LXA4) receptor (ALX) agonist, has been reported to possess anti‑fibrotic properties. The present study aimed to elucidate whether BML‑111 inhibits TGF‑β1‑induced mouse embryo lung fibroblast (NIH3T3 cell line) activation in vitro and bleomycin (BLM)‑induced pulmonary fibrosis in vivo. In vitro experiments demonstrated that BML‑111 treatment inhibits TGF‑β1‑induced NIH3T3 cell viability and the expression of smooth muscle α actin (α‑SMA), fibronectin and total collagen. Furthermore, this suppressive effect was associated with mothers against decapentaplegic homolog (Smad)2/3, extracellular signal‑regulated kinase (ERK) and Akt phosphorylation interference. In vivo experiments revealed that BML‑111 treatment markedly improved survival rate and ameliorated the destruction of lung tissue structure. It also reduced interleukin‑1β (IL‑1β), tumor necrosis factor‑α (TNF‑α) and TGF‑β1 expression in the BLM intratracheal mouse model. In addition, the expression ofα‑SMA and extracellular matrix (ECM) deposition (total collagen, hydroxyproline and fibronectin) were also suppressed following BML‑111 treatment. However, BOC‑2, an antagonist of ALX, partially weakened the effects of BML‑111. In conclusion, these results indicated that BML‑111 inhibits TGF‑β1‑induced fibroblasts activation and alleviates BLM‑induced pulmonary fibrosis. Therefore, BML‑111 may be used as a potential therapeutic agent for pulmonary fibrosis treatment.

BML-111 Reduces Neuroinflammation and Cognitive Impairment in Mice With Sepsis via the SIRT1/NF-κB Signaling Pathway

Sepsis is a life-threatening state of organ dysfunction caused by infection and which can induce severe neurological disorders that lead to neuroinflammation and cognitive impairment. Inflammation has been reported to cause neuronal apoptosis in sepsis, which can finally lead to cognitive impairment. Previous studies have suggested that BML-111 can exhibit anti-inflammatory and proresolution activities. Additionally, silent information regulator 1 (SIRT1) can inhibit the NF-κB signaling pathway in an inflammation state. However, the role of the SIRT1/NF-κB signaling pathway in the protective effects of BML-111 against sepsis-induced neuroinflammation and cognitive impairment remains unclear. This study aimed to determine the effects of BML-111 on neuroinflammation and cognitive impairment induced by sepsis. Male C57BL/6J mice were subjected to cecal ligation and puncture (CLP) or a sham operation. BML-111 was administered via intracerebroventricular injection (0.1 mg/kg) immediately after CLP. Boc-2 (50 μg/kg) was administered intracerebroventricularly 30 min before CLP, and EX527 (10 μg) was administered every 2 days for a total of three times before CLP, also intracerebroventricularly. Some of the surviving mice underwent open-field, novel-object-recognition, and fear-conditioning behavioral tests at 7 days after surgery. Some of the other surviving mice were killed at 24 h after surgery to assess synaptic damage (PSD95 and Synapsin1), markers of inflammation [tumor necrosis factor alpha (TNF-α) and interleukin (IL)-1β], cytoplasmic p65, nuclear p65, Ac- NF-κB and SIRT1. At 48 h after CLP, TUNEL and glia-activation by immunofluorescence investigations were performed on a separate cohort of surviving animals. The results suggested that sepsis resulted in cognitive impairment, which was accompanied by the decreased the expression of PSD95 and Synapsin1, increased amount of TUNEL-positive cells and the activation of glias, increased production of TNF-α and IL-1β, increased expression of nuclear p65, Ac- NF-κB, and decreased expression of SIRT1 and cytoplasmic p65. It is especially notable that these abnormalities could be reduced by BML-111 treatment. EX527, an SIRT1 inhibitor, abolished the effects of BML-111. These results demonstrate that BML-111 can reduce the neuroinflammation and cognitive impairment induced by sepsis via SIRT/NF-κB signaling pathway.

BML-111 alleviates acute lung injury through regulating the expression of lncRNA MALAT1

BML-111 is a lipoxin receptor agonist that plays a vital role on inflammation. MALAT1 is reported to mediate lung injury. ALI rat model was established using the method of venous cannula. Pulmonary microvascular endothelial cells (PMVEC) of rats were isolated using immunomagnetic separation method. Hematoxylin-eosin (HE) staining was performed to observe the lung injury degree. Real-time PCR and western blot were performed to detect the genes expression. ELIAS was used to determine the level of TNF-α and IL-6. RNA pull-down and RIP were carried out to affirm the relationship between MALAT1 and TLR4. The lung injury score and lung wet/dry weight ratio was significantly increased in ALI rats, while BML-111 treatment significantly decreased it, the HE staining directly revealed the lung injury. The expression of MALAT1 was decreased, while TLR4 was increased in ALI rats, BML-111 stimulation significantly reversed it. MALAT1 targets TLR4 to regulate its expression. TLR4 regulated the inflammation and cell apoptosis of PMVEC via NF-κB and p38 MAPK signaling pathway. The down-regulated MALAT1 mediates the mechanism of ALI by regulating of NF-κB and p38 MAPK signaling pathways via TLR4, while BML-111 stimulation significantly alleviated the ALI by regulating the expression of MALAT1.

BML-111 Protected LPS/D-GalN-Induced Acute Liver Injury in Rats

Lipoxins (LXs) display unique pro-resolving and anti-inflammatory functions in a variety of inflammatory conditions. The present study was undertaken to investigate the effects of BML-111 (5(S),6(R),7-trihydroxyheptanoic acid methyl ester), the agonist of lipoxin A₄ receptor, in a model of Lipopolysaccharides (LPS) and d-Galactosamine (d-GalN) induced acute liver injury, and to explore the mechanisms. Histopathological analyses were carried out to quantify liver injury degree. The activities of myeloperoxidase (MPO) were examined to evaluate the levels of neutrophil infiltration. The activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum were detected to evaluate the functions of the liver. The amounts of tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), and interleukin-1β (IL-1β) were measured using enzyme-linked immunosorbent assay (ELISA), and the expression levels of transforming growth factor-β1(TGF-β1) and cyclooxygenase-2 (COX-2) were examined using Western blotting. The antioxidant capacity, the activities of inducible nitric oxide synthase (iNOS), the contents of malondialdehyde (MDA) and nitric oxide (NO) were analyzed with the kits via biochemical analysis. We established the model of acute liver injury with lipopolysaccharide and d-Galactosamine (LPS/d-GalN): (1) histopathological results and MPO activities, with the activities of AST and ALT in serum, consistently demonstrated LPS and d-GalN challenge could cause severe liver damage, but BML-111 could prevent pathological changes, inhibit neutrophil infiltration, and improve the hepatic function; (2) LPS/d-GalN increased TNF-α, IL-1β, COX-2, and IL-10, while decreasing TGF-β1. However, BML-111 could repress LPS/d-GalN -induced TNF-α, IL-1β and COX-2, meanwhile increasing the expression levels of TGF-β1 and IL-10; (3) LPS/d-GalN inhibited the activities of superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (T-AOC), and hydroxyl radical-scavenging ability, simultaneously increasing the levels of MDA and NO, so also the activity of iNOS. Otherwise, BML-111 could reverse all the phenomena. In a word, BML-111 played a protective role in acute liver injury induced by LPS and d-GalN in rats, through improving antioxidant capacity and regulating the balance of inflammatory cytokines.

The Beneficial Effects of ETS-GS, a Novel Vitamin E Derivative, on a Rat Model of Crush Injury

Crush syndrome is a devastating condition leading to multiple organ failure. The mechanisms by which local traumatic injuries affect distant organs remain unknown. ETS-GS is a novel water-soluble, stable anti-oxidative agent composed of vitamin E derivative. Given that one of the main pathophysiological effects in crush syndrome is massive ischemia-reperfusion, reactive oxygen species (ROS) generated from the injured extremities would be systemically involved in distant organ damage. We investigated whether ETS-GS could suppress inflammatory response and improve mortality in a rat model of crush injury. Crush injury was induced by compression of bilateral hindlimbs for 6 h followed by release of compression. Seven-day survival was significantly improved by ETS-GS treatment. To estimate anti-oxidative and anti-inflammatory effects of ETS-GS, serum was collected 6 and 20 h after the injury. ETS-GS treatment significantly dampened the up-regulation of malondialdehyde and reduction of superoxide dismutase in the serum, which were induced by crush injury. Serum levels of interleukin 6 and high mobility group box 1 were significantly decreased in the ETS-GS group compared with those in the control group. Lung damage shown by hematoxylin-eosin staining at 20 h after the injury was ameliorated by the treatment. Ex vivo imaging confirmed that ETS-GS treatment reduced ROS generation in both the lung and the muscle following crush injury. The administration of ETS-GS could suppress ROS generation, systemic inflammation, and the subsequent organ damage, thus improving survival in a rat model of crush injury. These findings suggest that ETS-GS can become a novel therapeutic agent against crush injury.

Resolvin D1 protects the liver from ischemia/reperfusion injury by enhancing M2 macrophage polarization and efferocytosis

Resolution of inflammation is an active process involving a novel category of lipid factors known as specialized pro-resolving lipid mediators, which includes Resolvin D1 (RvD1). While accumulating evidence suggests that RvD1 counteracts proinflammatory signaling and promotes resolution, the specific cellular targets and mechanisms of action of RvD1 remain largely unknown. In the present study, we investigated the role and molecular mechanisms of RvD1 in ischemia/reperfusion (IR)-induced sterile liver inflammation. Male C57BL/6 mice underwent 70% hepatic ischemia for 60min, followed by reperfusion. RvD1 (5, 10, and 15μg/kg, i.p.) was administered to the mice 1h before ischemia and then immediately prior to reperfusion. RvD1 attenuated IR-induced hepatocellular damage and the proinflammatory response. In purified Kupffer cells (KCs) from mice exposed to IR, the levels of M1 marker genes (Nos2a and Cd40) increased, while those of M2 marker genes (Arg1, Cd206, and Mst1r) decreased, demonstrating a proinflammatory shift. RvD1 markedly attenuated these changes. Depletion of KCs by liposome clodronate abrogated the effects of RvD1 on proinflammatory mediators and macrophage polarization. In addition, RvD1 attenuated increases in myeloperoxidase activity and Cxcl1 and Cxcl2 mRNA expression. RvD1 markedly augmented the efferocytic activity of KCs, as indicated by increases in F4/80(+)Gr-1(+) cells in the liver. However, antagonist pretreatment or gene silencing of the RvD1 receptor, ALX/FPR2, abrogated the anti-inflammatory and pro-resolving actions of RvD1. These data indicate that RvD1 ameliorates IR-induced liver injury, and this protection is associated with enhancement of M2 polarization and efferocytosis via ALX/FPR2 activation.

Lipoxin A4 Preconditioning Attenuates Intestinal Ischemia Reperfusion Injury through Keap1/Nrf2 Pathway in a Lipoxin A4 Receptor Independent Manner

Oxidative stress plays a critical role in the pathogenesis of intestinal ischemia reperfusion (IIR) injury. Enhancement in endogenous Lipoxin A4 (LXA4), a potent antioxidant and mediator, is associated with attenuation of IIR. However, the effects of LXA4 on IIR injury and the potential mechanisms are unknown. In a rat IIR (ischemia 45 minutes and subsequent reperfusion 6 hours) model, IIR caused intestinal injury, evidenced by increased serum diamine oxidase, D-lactic acid, intestinal-type fatty acid-binding protein, and the oxidative stress marker 15-F2t-Isoprostane. LXA4 treatment significantly attenuated IIR injury by reducing mucosal 15-F2t-Isoprostane and elevating endogenous antioxidant superoxide dismutase activity, accompanied with Keap1/Nrf2 pathway activation. Meanwhile, LXA4 receptor antagonist Boc-2 reversed the protective effects of LXA4 on intestinal injury but failed to affect the oxidative stress and the related Nrf2 pathway. Furthermore, Nrf2 antagonist brusatol reversed the antioxidant effects conferred by LXA4 and led to exacerbation of intestinal epithelium cells oxidative stress and apoptosis, finally resulting in a decrease of survival rate of rat. Meanwhile, LXA4 pretreatment upregulated nuclear Nrf2 level and reduced hypoxia/reoxygenation-induced IEC-6 cell damage and Nrf2 siRNA reversed this protective effect of LXA4 in vitro. In conclusion, these findings suggest that LXA4 ameliorates IIR injury by activating Keap1/Nrf2 pathway in a LXA4 receptor independent manner.

The significance and mechanism of propofol on treatment of ischemia reperfusion induced lung injury in rats

This study is aimed to investigate the efficacy and underlying the mechanism of propofol in treatment of ischemia reperfusion (IR)-induced lung injury in rats, providing a novel insight of therapeutic strategy for IR-induced lung injury. 120 healthy SD rats were selected and randomly divided into sham operation group, IR group, and propofol group (40 rats per group). Bronchoalveolar lavage fluid (BALF) protein content, serum protein content, lung permeability index, lung water content rate, methane dicarboxylic aldehyde (MDA) in lung tissue, superoxide dismutase (SOD), nitric oxide (NO), endothelin (ET-1), toll-like receptor 4 (TLR4), nuclear factor (NF-κB), and tumor necrosis factor-α (TNF-α) were examined and compared among different groups to evaluate the therapeutical effects of propofol on IR-induced lung injury and analyze the mechanism. In sham operation group, neither change in lung tissue nor pulmonary interstitial edema or alveolar wall damage was found under microscope; in IR group, marked pulmonary interstitial edema and alveolar wall damage complicated with inflammatory cell infiltration and hemorrhage were found; in propofol group, alveolar wall widening was observed, however, hemorrhage in alveolar cavity, inflammatory infiltration and tissue damage were less significant than in IR group. At 3 h after reperfusion, BALF protein content, lung permeability index, and lung water content rate were all significantly increased in IR group and propofol group, while the serum protein content was significantly lower than sham operation group (p < 0.05). Moreover, we found that the change of above parameters in propofol group was less significant than in IR group (p < 0.05). No statistically significant difference was found in ET-1 levels in different groups (p > 0.05). In contrast, MDA and NO in IR group and propofol group were significantly increased, while SOD activity was significantly decreased (p < 0.05). Furthermore, the change of above parameters in propofol group was less significant than in IR group (p < 0.05). In addition, mRNAs of TLR4, NF-κB, and TNF-α were significantly increased in IR group and propofol group (p < 0.05) with more significant change in IR group compared with propofol group (p < 0.05). Propofol has protective effects against IR-induced lung injury by improving activity of oxygen radical and restoring NO/ET-1 dynamic balance. Besides, regulation of TLR4, NF-κB, and TNF-α by propofol also play important role in alleviating IR-induced lung injury.

Effect of BML-111 on the intestinal mucosal barrier in sepsis and its mechanism of action

5(S),6(R)-7-trihydroxymethyl heptanoate (BML-111) is an lipoxin A4 receptor agonist, which modulates the immune response and attenuates hemorrhagic shock-induced acute lung injury. However, the role of BML-111 in sepsis and in the intestinal mucosal barrier are not well understood. Therefore, the present study was designed to investigate the effect of BML-111 on the intestinal mucosal barrier in a rat model of sepsis. Furthermore, the molecular mechanism of action of BML-111 was evaluated. The cecal ligation and puncture-induced rat model of sepsis was constructed, and BML-111 was administered at three different doses. The results revealed that BML-111 suppressed the elevation of the pro-inflammatory cytokines tumor necrosis factor-α and interleukin-6, while enhancing the elevation of the anti-inflammatory cytokine transforming growth factor-β in the intestine. In addition, BML-111 significantly upregulated rat defensin-5 mRNA expression levels and downregulated the induction of cell apoptosis as well as caspase-3 activity in the intestine. All these results demonstrated that BML-111 exerted protective effects on the intestinal mucosal barrier in sepsis. Further, it was indicated that alterations in the expression of toll-like receptor (TLR)2 and TLR4 may be one of the molecular mechanisms underlying the protective effect of BML-111. The present study therefore suggested that BML-111 may be a novel therapeutic agent for sepsis.

Maresin 1 mitigates LPS-induced acute lung injury in mice

BACKGROUND AND PURPOSE

Acute lung injury (ALI) is a severe illness with a high rate of mortality. Maresin 1 (MaR1) was recently reported to regulate inflammatory responses. We used a LPS-induced ALI model to determine whether MaR1 can mitigate lung injury.

EXPERIMENTAL APPROACH

Male BALB/c mice were injected, intratracheally, with either LPS (3 mg·kg(-1) ) or normal saline (1.5 mL·kg(-1) ). After this, normal saline, a low dose of MaR1 (0.1 ng per mouse) or a high dose of MaR1 (1 ng per mouse) was given i.v. Lung injury was evaluated by detecting arterial blood gas, pathohistological examination, pulmonary oedema, inflammatory cell infiltration, inflammatory cytokines in the bronchoalveolar lavage fluid and neutrophil-platelet interactions.

KEY RESULTS

The high dose of MaR1 significantly inhibited LPS-induced ALI by restoring oxygenation, attenuating pulmonary oedema and mitigating pathohistological changes. A combination of elisa and immunohistochemistry showed that high-dose MaR1 attenuated LPS-induced increases in pro-inflammatory cytokines (TNF-α, IL-1β and IL-6), chemokines [keratinocyte chemokine, monocyte chemoattractant protein-5, macrophage inflammatory protein (MIP)-1α and MIP-1γ], pulmonary myeloperoxidase activity and neutrophil infiltration in the lung tissues. Consistent with these observations, flow cytometry and Western blotting indicated that MaR1 down-regulated LPS-induced neutrophil adhesions and suppressed the expression of intercellular adhesion molecule (ICAM)-1, P-selection and CD24.

CONCLUSIONS AND IMPLICATIONS

High-dose MaR1 mitigated LPS-induced lung injury in mice by inhibiting neutrophil adhesions and decreasing the levels of pro-inflammatory cytokines.

BML-111, a lipoxin receptor agonist, attenuates ventilator-induced lung injury in rats

Mechanical ventilation can cause structural and functional disturbances in the lung termed ventilator-induced lung injury (VILI). The aim of this study was to evaluate whether BML-111, a lipoxin receptor agonist, could attenuate VILI. Following induction of anesthesia and tracheostomy, Sprague-Dawley rats were ventilated with low tidal volume (6 mL/kg) or high tidal volume (20 mL/kg, HVT) for 4 h. Some rats subjected to HVT ventilation received BML-111 or vehicle (saline) by intraperitoneal injection. Some rats subjected to HVT and BML-111(1 mg/kg) received BOC-2 (a FPR2/ALX antagonist) intraperitoneally 30 min before BML-111. Sham rats were tracheotomized without ventilation. Treatment with BML-111 attenuated VILI, as evidenced by improved oxygenation and reduced histological injury compared with HVT-induced lung injury. BML-111 decreased indices of inflammation such as interleukin 1β, interleukin 6, tumor necrosis factor α, and bronchoalveolar lavage neutrophil infiltration. Administration with BML-111 suppressed the decrement of the nuclear factor κB (NF-κB) inhibitor IκB-α, diminished NF-κB activation, and reduced activation of mitogen-activated protein kinase in VILI. This study indicates that BML-111 attenuated VILI via a NF-κB and mitogen-activated protein kinase dependent mechanism. BML-111 may be a promising strategy for alleviation of VILI in patients subjected to mechanical ventilation.

Resolvin D1 promotes the interleukin-4-induced alternative activation in BV-2 microglial cells

Background

Microglia play key roles in innate immunity, homeostasis, and neurotropic support in the central nervous system. Similar to macrophages, microglia adopt two different activation phenotypes, the classical and alternative activation. Resolvin D1 (RvD1) is considered to display potent anti-inflammatory and pro-resolving actions in inflammatory models. In this present study, we investigate the effect of RvD1 on IL-4-induced alternative activation in murine BV-2 microglial cells.

Methods

BV-2 cells were incubated with RvD1 alone, IL-4 alone, or the combination of RvD1 and IL-4. Western blot and immunofluorescence were performed to detect protein levels of alternative activation markers arginase 1 (Arg1), chitinase 3-like 3 (Ym1). Moreover, we investigated the effects of RvD1 on IL-4-induced activation of signal transducer and activators of transcription 6 (STAT6) and peroxisome proliferator-activated receptor gamma (PPARγ).

Results

RvD1 promoted IL-4-induced microglia alternative activation by increasing the expression of Arg1 and Ym1. RvD1 also enhanced phosphorylation of STAT6, nuclear translocation of PPARγ and the DNA binding activity of STAT6 and PPARγ. These effects were reversed by butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe (a formyl peptide receptor 2 antagonist). Further, the effects of RvD1 and IL-4 on Arg1 and Ym1 were blocked by the application of leflunomide (a STAT6 inhibitor) or GW9662 (a PPARγ antagonist).

Conclusions

Our studies demonstrate that RvD1 promotes IL-4-induced alternative activation via STAT6 and PPARγ signaling pathways in microglia. These findings suggest that RvD1 may have therapeutic potential for neuroinflammatory diseases.