hucMSC Conditioned Medium Ameliorate Lipopolysaccharide-Induced Acute Lung Injury by Suppressing Oxidative Stress and Inflammation via Nrf2/NF-κB Signaling Pathway.

Acute lung injury (ALI) is a common clinical syndrome in the cardiac intensive care unit with a high mortality rate. Inflammation and oxidative stress have been reported to play a crucial role in the development of ALI. Previous studies have shown that human umbilical cord mesenchymal stem cells (hucMSCs) have anti-inflammatory and antioxidative effects in various diseases. However, the anti-inflammatory and antioxidative effects of the hucMSC conditioned medium (CM) on LPS-induced ALI remain unclear. Therefore, in this study, we assessed whether the hucMSC conditioned medium could attenuate LPS-induced ALI and the underlying mechanisms. Mice were randomly divided into four groups: the control group, PBS group, LPS+PBS group, and LPS+CM group. The lung histopathology and bronchoalveolar lavage fluid (BALF) were analyzed after intervention. The Nrf2/NF-κB signaling pathway and its downstream target genes were tested, and the cytokines and growth factors in CM were also measured. The results showed that CM significantly attenuated the histological alterations; decreased the wet/dry weight ratio; reduced the levels of MPO, MDA and ROS; increased SOD and GSH activity; and downregulated the level of proinflammatory cytokines such as IL-1β, IL-6, and TNF-α. Furthermore, CM promoted the expression of Nrf2 and its target genes NQ01, HO-1, and GCLC and inhibited the expression of NF-κB and its target genes IL-6, IL-1β, and TNF-α. These effects may be closely related to the large amounts of cytokines and growth factors in the CM. In conclusion, our results demonstrated that CM could attenuate LPS-induced ALI, probably due to inhibition of inflammation and oxidative stress via the Nrf2/NF-κB signaling pathway.

Tang Y ，Ding F ，Wu C ，Liu B ... -  《-》

Downregulated microRNA-27b attenuates lipopolysaccharide-induced acute lung injury via activation of NF-E2-related factor 2 and inhibition of nuclear factor κB signaling pathway.

Acute lung injury (ALI) is a life-threatening, diffuse heterogeneous lung injury characterized by acute onset, pulmonary edema, and respiratory failure. Lipopolysaccharide (LPS) is a leading cause for ALI and when administered to a mouse it induces a lung phenotype exhibiting some of the clinical characteristics of human ALI. This study focused on investigating whether microRNA-27b (miR-27b) affects ALI in a mouse model established by LPS-induction and to further explore the underlying mechanism. After model establishment, the mice were treated with miR-27b agomir, miR-27b antagomir, or D-ribofuranosylbenzimidazole (an inhibitor of nuclear factor-E2-related factor 2 [Nrf2]) to determine levels of miR-27b, Nrf2, nuclear factor kappa-light-chain-enhancer of activated B cells nuclear factor κB (NF-κB), p-NF-κB, and heme oxygenase-1 (HO-1). The levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) in bronchoalveolar lavage fluid (BALF) were determined. The results of luciferase activity suggested that Nrf2 was a target gene of miR-27b. It was indicated that the Nrf2 level decreased in lung tissues from ALI mice. The downregulation of miR-27b decreased the levels of IL-1β, IL-6, and TNF-α in BALF of ALI mice. Downregulated miR-27b increased Nrf2 level, thus enhancing HO-1 level along with reduction of NF-κB level as well as the extent of NF-κB phosphorylation in the lung tissues of the transfected mice. Pathological changes were ameliorated in LPS-reduced mice elicited by miR-27b inhibition. The results of this study demonstrate that downregulated miR-27b couldenhance Nrf2 and HO-1 expressions, inhibit NF-κB signaling pathway, which exerts a protective effect on LPS-induced ALI in mice.

Huang Y ，Huang L ，Zhu G ，Pei Z ，Zhang W ... -  《-》

Orientin relieves lipopolysaccharide-induced acute lung injury in mice: The involvement of its anti-inflammatory and anti-oxidant properties.

Oxidative stress and inflammatory responses are nearly involved in the pathogenesis of various diseases, including acute lung injury (ALI). Orientin (Ori), a flavonoid component extracted from natural plants, displayed anti-inflammatory and antioxidant properties in our previous studies. In the current study, we aimed to investigate the amelioration effect of Ori on lipopolysaccharide (LPS)-induced ALI, and we further explored the potential molecular mechanisms. The present results indicated that Ori effectively alleviated LPS-induced ALI by improving the histological changes of lung; decreasing the lung W/D ratio and protein levels, the release of inflammatory cells and cytokines into the bronchoalveolar lavage fluid (BALF); inhibiting nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and high mobility group box 1 (HMGB1) protein expression; reducing malondialdehyde (MDA) formation and reactive oxygen species (ROS) generation; and increasing the content of glutathione (GSH) and superoxide dismutase (SOD) contents. Moreover, Ori treatment not only significantly suppressed the LPS-induced nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome, and nuclear factor-kappa B (NF-κB) signaling pathway activation, but also obviously restored the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), NAD (P) H: quinone oxidoreductase (NQO1), glutamate-cysteine ligase catalytic (GCLC), and heme oxygenase 1 (HO-1) expression in the lung; all of which are reduced by LPS. Taken together, these data suggested that Ori plays an important role in the protection against ALI by suppressing inflammation and oxidative stress which may be strongly related to the suppression of NLRP3 inflammasome and NF-κB activation, as well as the upregulation of the Nrf2 signaling pathway.

Xiao Q ，Cui Y ，Zhao Y ，Liu L ，Wang H ，Yang L ... -  《-》

The protective effects of Thalictrum minus L. on lipopolysaccharide-induced acute lung injury.

Thalictrum minus L., a Mongolian folk medicinal plant, was applied for the treatment of bacterial and fungal infection, tuberculosis and lung inflammation. The present work aims to elucidate the protective effects of Thalictrum minus L.(TML) against lipopolysaccharide (LPS)-induced acute lung injury and the underlying mechanisms. The mice model of acute lung injury was induced by LPS via endotracheal drip, and TML (10, 20, 40 mg/kg) were administered orally 1 h prior to LPS. The efficacy and molecular mechanisms in the presence or absence of TML were investigated. We demonstrated that treatment with TML aqueous extract protected the mice from acute lung injury induced by LPS administration. TML significantly inhibited weight loss in mice, decreased the lung wet to dry weight (W/D) ratios and attenuated lung histopathological changes, such as infiltration of inflammatory cells and coagulation, pulmonary edema. Furthermore, we found that TML markedly reduced the LPS-induced inflammatory cytokines including tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), decreased nitric oxide (NO), and increased superoxide dismutase (SOD) in bronchoalveolar lavage fluid (BALF), and effectively ameliorated LPS-induced increased total protein, leukocyte and macrophages in BALF. In addition, TML pronouncedly suppressed the activation of the MAPKs p38-NLRP3/caspase-1 and COX2, increased the expression of p-AMPK-Nrf2, and suppressed the expression of KEAP, apoptotic-related protein as well as autophagy. These results suggested that TML ameliorated LPS-induced acute lung injury by inhibiting the release of inflammatory cytokines and reducing oxidative damage associated with the MAPKs p38-NLRP3/caspase-1 and COX2 signaling pathways, AMPK-Nrf2/KEAP signaling pathways, as well as apoptosis and autophagy.

Badamjav R ，Sonom D ，Wu Y ，Zhang Y ，Kou J ，Yu B ，Li F ... -  《-》

Therapeutic effect of Mahaenggamseok-tang on neutrophilic lung inflammation is associated with NF-κB suppression and Nrf2 activation.

Mahaenggamseok-tang (MHGST), an herbal formula in traditional Asian medicine, has been used to treat patients with various pulmonary diseases including common cold and influenza. However, the potential therapeutic effect of MHGST on acute lung injury (ALI), a leading cause of death worldwide, and the anti-inflammatory mechanisms of MHGST remained less understood. The methanol extract of MHGST was prepared and fingerprinted by HPLC. For the induction of ALI, C57BL/6 mice (n=5/group) received a single intraperitoneal (i.p.) injection of LPS. Referring to the dose for patients, two different amounts of MHGST were delivered in an aerosol to mouse lungs via trachea 2h after the i.p. LPS administration. Lung histology, bronchoalveolar lavage fluid, myeloperoxidase (MPO) activity, and the expression of inflammatory and Nrf2-dependent genes were analyzed to determine the effect of MHGST on lung inflammation. For mechanistic studies, western blotting and semi-quantitative RT-PCR were conducted using RAW 264.7 cells. When administered 2h after the onset of ALI, MHGST relieved lung pathology characteristic to ALI, with decreases of neutrophil infiltration and MPO activity. While suppressing the expression of inflammatory genes, MHGST increased the expression of Nrf2-dependent genes in ALI mouse lungs. Concordantly, MHGST activated Nrf2 activity while suppressing NF-κB in RAW 264.7 cells. MHGST suppressed neutrophilic lung inflammation, a hallmark of ALI, which was associated with the activation of anti-inflammatory Nrf2 and the suppression of pro-inflammatory NF-κB. Our results suggest that MHGST has a therapeutic potential against ALI.

Kim KH ，Lee JY ，Kwun MJ ，Choi JY ，Han CW ，Ha KT ，Jeong SI ，Jeong HS ，Joo M ... -  《-》