BCL6 attenuates hyperoxia-induced lung injury by inhibiting NLRP3-mediated inflammation in fetal mouse

BACKGROUND

The transcriptional repressor B-cell lymphoma 6 (BCL6) has been reported to inhibit inflammation. So far, experimental evidence for the role of BCL6 in bronchopulmonary dysplasia (BPD) is lacking. Our study investigated the roles of BCL6 in the progression of BPD and its downstream mechanisms.

METHODS

Hyperoxia or lipopolysaccharide (LPS) was used to mimic the BPD mouse model. To investigate the effects of BCL6 on BPD, recombination adeno-associated virus serotype 9 expressing BCL6 (rAAV9-BCL6) and BCL6 inhibitor FX1 were administered in mice. The pulmonary pathological changes, inflammatory chemokines and NLRP3-related protein were observed. Meanwhile, BCL6 overexpression plasmid was used in human pulmonary microvascular endothelial cells (HPMECs). Cell proliferation, apoptosis, and NLRP3-related protein were detected.

RESULTS

Either hyperoxia or LPS suppressed pulmonary BCL6 mRNA expression. rAAV9-BCL6 administration significantly inhibited hyperoxia-induced NLRP3 upregulation and inflammation, attenuated alveolar simplification and dysregulated angiogenesis in BPD mice, which were characterized by decreased mean linear intercept, increased radical alveolar count and alveoli numbers, and the upregulated CD31 expression. Meanwhile, BCL6 overexpression promoted proliferation and angiogenesis, inhibited apoptosis and inflammation in hyperoxia-stimulated HPMECs. Moreover, administration of BCL6 inhibitor FX1 arrested growth and development. FX1-treated BPD mice exhibited exacerbation of alveolar pathological changes and pulmonary vessel permeability, with upregulated mRNA levels of pro-inflammatory cytokines and pro-fibrogenic factors. Furthermore, both rAAV9-BCL6 and FX1 administration exerted a long-lasting effect on hyperoxia-induced lung injury (≥4 wk).

CONCLUSIONS

BCL6 inhibits NLRP3-mediated inflammation, attenuates alveolar simplification and dysregulated pulmonary vessel development in hyperoxia-induced BPD mice. Hence, BCL6 may be a target in treating BPD and neonatal diseases.

MiR-155-5p Attenuates Vascular Smooth Muscle Cell Oxidative Stress and Migration via Inhibiting BACH1 Expression

The malfunction of vascular smooth muscle cells (VSMCs) is an initiating factor in the pathogenesis of pathological vascular remodeling, including hypertension-related vascular lesions. MicroRNAs (miRNAs) have been implicated in the pathogenesis of VSMC proliferation and migration in numerous cases of cardiovascular remodeling. The evidence for the regulatory role of miR-155-5p in the development of the cardiovascular system has been emerging. However, it was previously unclear whether miR-155-5p participated in the migration of VSMCs under hypertensive conditions. Thus, we aimed to define the exact role and action of miR-155-5p in VSMC migration by hypertension. Here, we detected that the level of miR-155-5p was lower in primary VSMCs from spontaneously hypertensive rats (SHRs). Its overexpression attenuated, while its depletion accelerated, the migration and oxidative damage of VSMCs from SHRs. Our dual-luciferase reporter assay showed that miRNA-155-5p directly targeted the 3'-untranslated region (3'-UTR) of BTB and CNC homology 1 (BACH1). The miR-155-5p mimic inhibited BACH1 upregulation in SHR VSMCs. By contrast, the deletion of miR-155-5p further elevated the upregulation of BACH1 in SHR-derived VSMCs. Importantly, the overexpression of miR-155-5p and knockdown of BACH1 had synergistic effects on the inhibition of VSMCs in hypertension. Collectively, miR-155-5p attenuates VSMC migration and ameliorates vascular remodeling in SHRs, via suppressing BACH1 expression.

4-OI ameliorates bleomycin-induced pulmonary fibrosis by activating Nrf2 and suppressing macrophage-mediated epithelial-mesenchymal transition

OBJECTIVES

Pulmonary fibrosis (PF) is a chronic and refractory interstitial lung disease with limited therapeutic options. 4-octyl itaconate (4-OI), a cell-permeable derivative of itaconate, has been shown to have anti-oxidative and anti-inflammatory properties. However, the effect and the underlying mechanism of 4-OI on PF are still unknown.

METHODS

WT or Nrf2 knockout (Nrf2^-/-) mice were intratracheally injected with bleomycin (BLM) to establish PF model and then treated with 4-OI. The mechanism study was performed by using RAW264.7 cells, primary macrophages, and conditional medium-cultured MLE-12 cells.

RESULTS

4-OI significantly alleviated BLM-induced PF and EMT process. Mechanism studies have found that 4-OI can not only directly inhibit EMT process, but also can reduce the production of TGF-β1 by restraining macrophage M2 polarization, which in turn inhibits EMT process. Moreover, the effect of 4-OI on PF and EMT depends on Nrf2.

CONCLUSION

4-OI ameliorates BLM-induced PF in an Nrf2-dependent manner, and its role in alleviating PF is partly due to the direct inhibition on EMT, and partly through indirect inhibition of M2-mediated EMT. These findings suggested that 4-OI has great clinical potential to develop as a new anti-fibrotic agent for PF therapy.

Maternal propionate supplementation ameliorates glucose and lipid metabolic disturbance in hypoxia-induced fetal growth restriction

Intrauterine growth restriction (IUGR), one of the major complications of pregnancy, is characterized by low birth weight and results in higher risks for long-term problems including developing metabolic and cardiovascular diseases. Short-chain fatty acids (SCFAs), especially propionate, have been reported to correct glucose and lipid disorders in metabolic diseases. We hypothesized that maternal propionate supplementation could prevent glucose and lipid metabolic disturbance in hypoxia-induced IUGR. Here, in our study, maternal hypoxia was induced from gestational day (GD) 11 to GD 17.5 to establish an IUGR mouse model. Maternal propionate treatment reversed reduced birth weight in male IUGR offspring. Hepatic transcriptomics demonstrated that SP treatment significantly lowered glucose and lipid metabolism-related genes (Scd1, G6pc, Pck1 and Fasl) in IUGR offspring. KOG enrichment analysis showed that propionate-induced down-regulated differential expressed genes (DEGs) mainly belonged to lipid transport and metabolism. KEGG enrichment results showed that the down-regulated DEGs were mostly enriched in PPAR and FoxO signaling pathways. We also found that maternal oral administration of SP decreased serum lipid content, attenuated hepatic insulin resistance and liver lipid accumulation, reduced hepatic key gene expressions of gluconeogenesis and lipogenesis, increased energy expenditure and improved liver function in 11-week-old male IUGR offspring. These results indicate that maternal propionate supplementation increases birth weight and corrects hepatic glucose and lipid metabolic disturbance and energy expenditure in male mice born with IUGR, which may provide a basis for using propionate to treat IUGR disease.

Dehydrocostus Lactone Attenuates Methicillin-Resistant Staphylococcus aureus-Induced Inflammation and Acute Lung Injury via Modulating Macrophage Polarization

Dehydrocostus lactone (DHL), a natural sesquiterpene lactone isolated from the traditional Chinese herbs Saussurea lappa and Inula helenium L., has important anti-inflammatory properties used for treating colitis, fibrosis, and Gram-negative bacteria-induced acute lung injury (ALI). However, the effects of DHL on Gram-positive bacteria-induced macrophage activation and ALI remains unclear. In this study, we found that DHL inhibited the phosphorylation of p38 MAPK, the degradation of IκBα, and the activation and nuclear translocation of NF-κB p65, but enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and the expression of Nrf2 and HO-1 in lipoteichoic acid (LTA)-stimulated RAW264.7 cells and primary bone-marrow-derived macrophages (BMDMs). Given the critical role of the p38 MAPK/NF-κB and AMPK/Nrf2 signaling pathways in the balance of M1/M2 macrophage polarization and inflammation, we speculated that DHL would also have an effect on macrophage polarization. Further studies verified that DHL promoted M2 macrophage polarization and reduced M1 polarization, then resulted in a decreased inflammatory response. An in vivo study also revealed that DHL exhibited anti-inflammatory effects and ameliorated methicillin-resistant Staphylococcus aureus (MRSA)-induced ALI. In addition, DHL treatment significantly inhibited the p38 MAPK/NF-κB pathway and activated AMPK/Nrf2 signaling, leading to accelerated switching of macrophages from M1 to M2 in the MRSA-induced murine ALI model. Collectively, these data demonstrated that DHL can promote macrophage polarization to an anti-inflammatory M2 phenotype via interfering in p38 MAPK/NF-κB signaling, as well as activating the AMPK/Nrf2 pathway in vitro and in vivo. Our results suggested that DHL might be a novel candidate for treating inflammatory diseases caused by Gram-positive bacteria.

Sodium Propionate Enhances Nrf2-Mediated Protective Defense Against Oxidative Stress and Inflammation in Lipopolysaccharide-Induced Neonatal Mice

Background

Alveolar arrest and the impaired angiogenesis caused by chronic inflammation and oxidative stress are two main factors in bronchopulmonary dysplasia (BPD). Short-chain fatty acids (SCFAs), especially propionate, possess anti-oxidant and anti-inflammatory effects. The present study was designed to examine the roles of sodium propionate (SP) on lipopolysaccharide (LPS)-challenged BPD and its potential mechanisms.

Methods

WT, Nrf2^-/- mice and pulmonary microvascular endothelial cells (HPMECs) were used in this study. LPS was performed to mimic BPD model both in vivo and vitro. Lung histopathology, inflammation and oxidative stress-related mRNA expressions in lungs involved in BPD pathogenesis were investigated. In addition, cell viability and angiogenesis were also tested.

Results

The increased nuclear factor erythroid 2-related factor (Nrf2) and decreased Kelch-like ECH-associated protein-1 (Keap-1) expressions were observed after SP treatment in the LPS-induced neonatal mouse model of BPD. In LPS-induced wild-type but not Nrf2^-/- neonatal mice, SP reduced pulmonary inflammation and oxidative stress and exhibited obvious pathological alterations of the alveoli. Moreover, in LPS-evoked HPMECs, SP accelerated Nrf2 nuclear translocation presented and exhibited cytoprotective and pro-angiogenesis effects. In addition, SP diminished the LPS-induced inflammatory response by blocking the activation of nuclear factor-kappa B pathway. Moreover, pretreatment with ML385, an Nrf2 specific inhibitor, offsets the beneficial effects of SP on inflammation, oxidative stress and angiogenesis in LPS-evoked HPMECs.

Conclusion

SP protects against LPS-induced lung alveolar simplification and abnormal angiogenesis in neonatal mice and HPMECs in an Nrf2-dependent manner.

Sophoricoside attenuates lipopolysaccharide-induced acute lung injury by activating the AMPK/Nrf2 signaling axis

Sophoricoside (SOP), an isoflavone glycoside isolated from seed of Sophora japonica L., has been reported to have various pharmacological activities, including anti-cancer, anti-allergy and anti-inflammation. However, the effect of SOP on lipopolysaccharides (LPS)-acute lung injury (ALI) is completely unclear. Here, we found that SOP pretreatment significantly ameliorated LPS-induced pathological damage, tissue permeability, neutrophil infiltration and the production of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) in a murine model of ALI. Besides, SOP reduced the production of pro-inflammatory mediators such as iNOS, NO and inflammatory cytokines including TNF-α, IL-1β and IL-6 in LPS-stimulated RAW264.7 cells and bone marrow derived macrophages. Interestingly, treatment with SOP exhibited no effect on the activation of NF-κB and MAPKs in macrophages but prominently accelerated the expression and nuclear translocation of Nrf2. By using ML385, a specific Nrf2 inhibitor, we found that inhibition of Nrf2 abolished the inhibitory effect of SOP on LPS-induced iNOS expression, NO production as well as pro-inflammatory cytokine generation. SOP also activated AMPK, an upstream protein of Nrf2, under LPS stimuli. Furthermore, we demonstrated that the accelerated expression of Nrf2 induced by SOP was reversed by interference with the AMPK inhibitor Compound C. Taken together, our results suggested that SOP attenuated LPS-induced ALI in AMPK/Nrf2 dependent manner and indicated that SOP might be a potential therapeutic candidate for treating ALI/ARDS.

Salvinorin A protects against methicillin resistant staphylococcus aureus-induced acute lung injury via Nrf2 pathway

Salvinorin A (SA), a neoclerodane diterpene, is isolated from the dried leaves ofSalvia divinorum. SA has traditionally been used treatments for chronic pain diseases. Recent research has demonstrated that SA possesses the anti-inflammatory property. The present study aim to explore the effects and potentialmechanisms ofSA in protection against Methicillin Resistant Staphylococcus aureus (MRSA)-induced acute lung injury (ALI). Here, we firstly found that verylowdosesof SA (50 μg/kg) could markedly decrease the infiltration of pulmonary neutrophils, mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) and then attenuated ALI cause by MRSA infection in mice. In vitro findings revealed that SA attenuated lipoteichoicacid-induced apoptosis, inflammation and oxidative stress in RAW264.7 cells. Mechanism research revealed that SA increased both mRNA levels and protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and up-regulated mRNA expression of its downstream genes (HO-1, Gclm, Trx-1, SOD1 and SOD2). Additionally, Nrf2 knockout mice abolished the inhibitory effect of SA on neutrophil accumulation and oxidative stress in MRSA-induced ALI. In conclusion, SA attenuates MRSA-induced ALI via Nrf2 signaling pathways.

Nrf2 protects against seawater drowning-induced acute lung injury via inhibiting ferroptosis

Background

Ferroptosis is a new type of nonapoptotic cell death model that was closely related to reactive oxygen species (ROS) accumulation. Seawater drowning-induced acute lung injury (ALI) which is caused by severe oxidative stress injury, has been a major cause of accidental death worldwide. The latest evidences indicate nuclear factor (erythroid-derived 2)-like 2 (Nrf2) suppress ferroptosis and maintain cellular redox balance. Here, we test the hypothesis that activation of Nrf2 pathway attenuates seawater drowning-induced ALI via inhibiting ferroptosis.

Methods

we performed studies using Nrf2-specific agonist (dimethyl fumarate), Nrf2 inhibitor (ML385), Nrf2-knockout mice and ferroptosis inhibitor (Ferrostatin-1) to investigate the potential roles of Nrf2 on seawater drowning-induced ALI and the underlying mechanisms.

Results

Our data shows that Nrf2 activator dimethyl fumarate could increase cell viability, reduced the levels of intracellular ROS and lipid ROS, prevented glutathione depletion and lipid peroxide accumulation, increased FTH1 and GPX4 mRNA expression, and maintained mitochondrial membrane potential in MLE-12 cells. However, ML385 promoted cell death and lipid ROS production in MLE-12 cells. Furthermore, the lung injury became more aggravated in the Nrf2-knockout mice than that in WT mice after seawater drowning.

Conclusions

These results suggested that Nrf2 can inhibit ferroptosis and therefore alleviate ALI induced by seawater drowning. The effectiveness of ferroptosis inhibition by Nrf2 provides a novel therapeutic target for seawater drowning-induced ALI.

Sodium Propionate Attenuates the Lipopolysaccharide-Induced Epithelial-Mesenchymal Transition via the PI3K/Akt/mTOR Signaling Pathway

Short-chain fatty acids (SCFAs), especially propionate, originate from the fermentation of dietary fiber in the gut and play a key role in inhibiting pulmonary inflammation. Chronic inflammation may induce an epithelial-mesenchymal transition (EMT) in alveolar epithelial cells and result in fibrotic disorders. This study was designed to investigate the beneficial effect of sodium propionate (SP) on lipopolysaccharide (LPS)-induced EMT. In cultured BEAS-2B cells, the protein expression levels of E-cadherin, α-smooth muscle actin (SMA), and vimentin were 0.66 ± 0.20, 1.44 ± 0.23, and 1.32 ± 0.21 in the LPS group vs 1.11 ± 0.36 (P < 0.05), 1.04 ± 0.30 (P < 0.05), and 0.96 ± 0.13 (P < 0.01) in the LPS + SP group (mean ± standard deviation), respectively. Meanwhile, LPS-triggered inflammatory cytokines and extracellular proteins were also reduced by SP administration in BEAS-2B cells. Moreover, SP treatment attenuated inflammation, EMT, extracellular matrix (ECM) deposition, and even fibrosis in a mouse EMT model. In terms of mechanism, LPS-treated BEAS-2B cells exhibited a higher level of phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) phosphorylation, which was interrupted by SP treatment. It is worth noting that the blockade of the PI3K/Akt/mTOR signaling cascade reduced the LPS-evoked EMT process in BEAS-2B cells. These results suggest that SP can block LPS-induced EMT via inhibition of the PI3K/Akt/mTOR signaling cascade, which provides a basis for possible clinical use of SP in airway and lung diseases.

Hyperoside suppresses hypoxia-induced A549 survival and proliferation through ferrous accumulation via AMPK/HO-1 axis

BACKGROUND

Hypoxia is commonly existed in tumors and lead to cancer cell chemo/radio-resistance. It is well-recognized that tumor hypoxia is a major challenge for the treatment of various solid tumors. Hyperoside (quercetin-3-O-galactoside, Hy) possesses antioxidant effects and has been reported to protect against hypoxia/reoxygenation induced injury in cardiomyocytes. Therefore, Hy may be attractive compound applicable to hypoxia-related diseases.

PURPOSE

This study was designed to determine the role of Hy in hypoxia-induced proliferation of non-small cell lung cancer cells and the underlying mechanism.

STUDY DESIGN AND METHODS

A549, a human non-small cell lung cancer (NSCLC) cell line, was used in the present study. 1% O₂ was used to mimic the in vivo hypoxic condition of NSCLC. The potential mechanisms of Hy on hypoxia-induced A549 survival and proliferation, as well as the involvement of AMPK/HO-1 pathway were studied via CCK-8 assay, EdU staining, flow cytometry, qRT-PCR and western blot.

RESULTS

We showed that pretreatment with Hy suppressed hypoxia-induced A549 survival and proliferation in dose-dependent manner. In terms of mechanism, hypoxia-treated A549 showed the lower AMPK phosphorylation and the reduced HO-1 expression, which were reversed by Hy pretreatment. Both AMPK inhibitor (Compound C) and HO-1 activity inhibitor (Zinc protoporphyrin IX) abolished Hy-evoked A549 cell death under hypoxia stimuli. Of note, Ferrous iron contributed to Hy-induced A549 cell death under hypoxia, while Hy had no effect on lipid peroxidation under hypoxia.

CONCLUSION

Taken together, our results highlighted the beneficial role of Hy against hypoxia-induced A549 survival and proliferation through ferrous accumulation via AMPK/HO-1 axis.

Systematic nutrition management for locally advanced nasopharyngeal carcinoma patients undergoing radiotherapy

Objective

To evaluate the impact of systematic nutrition management (SNM) on nutritional status, treatment-related toxicity, quality of life (QoL), response rates, and survival in patients with locally advanced nasopharyngeal carcinoma (LA-NPC) treated by radiotherapy (RT).

Methods

In this retrospective study, 56 patients with LA-NPC were selected as nutrition management group (NG) for SNM during RT till 1 month later. Another 56 patients with LA-NPC receiving RT without SNM as control group (CG) were identified from the hospital database and matched pairs with NG patients according to age, gender, stage, and body mass index (BMI) prior to RT.

Results

At 1 month after RT, the percentage of malnourished patients with BMI <18.5 kg/m² was statistically significant reduced in NG as compared to the CG group (35.7% vs 58.9%, P=0.014). Nutritional indexes of body weight, hemoglobin, prealbumin, and lymphocyte in the NG were statistically significant higher than those in the CG group (P<0.05). NG patients had statistically significant less grade 3–4 oral mucositis during RT compared with the CG group (32.1% vs 51.8%, P=0.035). Furthermore, at 1 month after RT, an improved QoL was observed in NG patients with respect to physical, role and social functions, symptom scales of fatigue and pain, and the global health status as compared to the CG group (P<0.05). With a median follow-up of 24.8 months, there were no statistical differences between NG and CG (P>0.05) for the 2-year progression-free survival and overall survival (84.2% versus 79.5% and 94.7% versus 92.3%, respectively.).

Conclusion

SNM for LA-NPC patients treated by RT resulted in better nutritional status, reduced treatment-related toxicity and improved QoL.

Heme oxygenase-1 attenuates seawater drowning-induced acute lung injury through a reduction in inflammation and oxidative stress

OBJECTIVE

Heme oxygenase-1 (HO-1) plays a critical protective role in various insults-induced acute lung injury (ALI) through its strong anti-inflammatory, anti-oxidant, and anti-apoptotic properties, but its protective role and mechanism on seawater aspiration-induced acute lung injury remains unclear. This study aimed to explore the therapeutic potential and mechanism of HO-1 to attenuate seawater aspiration-induced ALI in vivo and in vitro.

METHODS

The viability and invasion of A549 cell were analyzed through cell counting kit-8 and lactate dehydrogenase release assay; the transcriptional level of inflammatory cytokines (TNF-α, IL-6, IL-8 and MCP-1) and cell proliferation-related cytokines (FoxM1, Ccnb1 and Cdc25C) in seawater-treated A549 cell were tested by qPCR; apoptotic cells were analyzed by flow cytometryd; HO-1mRNA and protein were determined by qPCR and western blotting; the fluorescent indicators (DCFH-DA, dihydroethidium, MitoSox Red and Fluo-4) were used to monitor generation of ROS and mitochondrial function. The lung wet/dry weight radio and lactate dehydrogenase activity, Sirius red staining, TUNEL assay and immunohistochemical staining with anti-pan Cytokeratin antibody were analyzed in seawater-drowning mice. The role of HO-1 on seawater-drowning pulmonary injury was explored via HO-1 activity inhibitors (Zinc protoporphyrin) in vitro and in vivo.

RESULTS

Seawater exposure decreased the cellular viability, increased the production of pro-inflammatory cytokines (IL-6, IL-8 and TNF-α), induced cellular apoptosis and inhibited the expression of cell proliferation-related cytokines (FoxM1, Ccnb1 and Cdc25C). Moreover, seawater exposure led to mitochondrial dysfunction in A549 cells. Supplement of HO-1 sepcific inducer (heme) or its catalytic product (biliverdin) significantly attenuated seawater-induced A549 damage and promoted cell proliferation. However, Zinc protoporphyrin abolished the beneficial effects of HO-1 on seawater drowning-induced pulmonary tissue injury.

CONCLUSION

HO-1 attenuates seawater drowning-induced lung injury by its anti-inflammatory, anti-oxidative, and anti-apoptosis function.

Deletion 101 residue at caveolin-1 scaffolding domain peptides impairs the ability of increasing heme oxygenase-1 activity

OBJECTIVE

Resident alveolar macrophages (AMs) are activated and release proinflammatory mediators and chemokines during acute lung injury. We have previous reported that caveolin-1 (Cav-1) scaffolding domain (CSD) peptide inhibited the proinflammatory cytokines expression by up-regulating heme oxygenase-1 (HO-1) activity. In this study, we aimed to investigate the effect of residue R101 in CSD peptide on the activity of HO-1 in AMs.

METHODS

The binding mode between HO-1 and CSD peptides (WT CSD and Δ101 CSD truncation peptides) was analyzed and the free energy was calculated. The inflammatory genes and M1/M2macrophage polarization-associated genes expression were measured by real-time PCR. The activities of HO-1 were determined by the spectrophotometical method. Western blot analyzed the content of Cav-1, HO-1, IκB and MAPK signals (phosphorylated ERK, JNK and p38 MAPK).

RESULTS

Δ101CSD peptide could bind to HO-1 protein and to disrupt the interaction of HO-1 and Cav-1. However, Δ101CSD peptide had lower activity of HO-1 in LPS-treated AMs compared with WT CSD. The expression of IL-1β and MCP-1 and NO content were decreased by WT CSD peptide in LPS treated AMs. However, only MCP-1 expression and NO content were downregulated byΔ101CSD peptide. Meanwhile, compared with those in LPS + hemin + WT CSD group, the mRNA expression of TNF-α, Cd86, IL-12b and NOS2 significantly increased while expression of IL10, Arg1 and CD163 significantly decreased in LPS + hemin + Δ101CSD group. The effect of WT CSD peptide on the inhibition of MAPK signaling pathway were stronger than Δ101 CSD peptide evidenced by the level of phosphorylated ERK, JNK and p38 MAPK.

CONCLUSION

Deletion of residue R101 impairs the ability of CSD peptide to increase HO-1 activity and to dampen inflammatory response in LPS-challenged rat AMs.

Caveolin-1 scaffolding domain peptides enhance anti-inflammatory effect of heme oxygenase-1 through interrupting its interact with caveolin-1

Caveolin-1(Cav-1) scaffolding domain (CSD) peptides compete with the plasma membrane Cav-1, inhibit the interaction of the proteins and Cav-1, and re-store the functions of Cav-1 binding proteins. Heme oxygenase-1 (HO-1) binds to Cav-1 and its enzymatic activity was inhibited. In this study, we investigated the effect of CSD peptides on interaction between HO-1 and Cav-1, and on the HO-1 activity in vitro and in vivo. Our data showed that CSD peptides decreased the compartmentalization of HO-1 and Cav-1, and increased the HO-1 activity both in LPS-treated alveolar macrophages and in mice. Meanwhile, CSD peptides obviously ameliorated the pathology changes in mice and lowered the following injury indexes: the wet/dry ratio of lung tissues, total cell numbers in bronchoalveolar lavage fluid and lactate dehydrogenase activity in the serum. Mechanistically, it was firstly found that CSD peptides promoted alveolar macrophages polarization to M2 phenotype and inhibited the IκB degeneration. Furthermore, CSD peptides down-regulated the expression of IL-1β, IL-6, TNF-α, MCP-1, and iNOS in alveolar macrophages and in lung tissue. However, the protective role of CSD peptides on LPS-induced acute lung injury in mice could be abolished by zinc protoporphyrin IX (ZnPP, a HO-1 activity inhibitor). In summary, CSD peptides have beneficial anti-inflammatory effects by restoring the HO-1 activity suppressed by Cav-1 on plasma membrane.

Methylene Blue Protects the Isolated Rat Lungs from Ischemia-Reperfusion Injury by Attenuating Mitochondrial Oxidative Damage

INTRODUCTION

Impaired mitochondrial function is a key factor attributing to the lung ischemia reperfusion injury (LIRI). Methylene blue (MB) has been reported to attenuate brain and renal ischemia-reperfusion injury. We hypothesized that MB also could have a protective effect against LIRI by preventing mitochondrial oxidative damage.

METHODS

Isolated rat lungs were assigned to the following four groups (n = 6): a sham group: perfusion for 105 min without ischemia; I/R group: shutoff of perfusion and ventilation for 45 min followed by reperfusion for 60 min; and I/R + MB group and I/R + glutathione (GSH) group: 2 mg/kg MB or 4 μM glutathione were intraperitoneally administered for 2 h, and followed by 45 min of ischemia and 60 min of reperfusion.

RESULTS

MB lessened pulmonary dysfunction and severe histological injury induced by ischemia-reperfusion injury. MB reduced the production of reactive oxygen species and malondialdehyde and enhanced the activity of superoxide dismutase. MB also suppressed the opening of the mitochondrial permeability transition pore and partly preserved mitochondrial membrane potential. Moreover, MB inhibited the release of cytochrome c from the mitochondria into the cytosol and decreased apoptosis. Additionally, MB downregulated the mRNA expression levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-18).

CONCLUSION

MB protects the isolated rat lungs against ischemia-reperfusion injury by attenuating mitochondrial damage.

Biliverdin Protects the Isolated Rat Lungs from Ischemia-reperfusion Injury via Antioxidative, Anti-inflammatory and Anti-apoptotic Effects

Background:

Biliverdin (BV) has a protective role against ischemia-reperfusion injury (IRI). However, the protective role and potential mechanisms of BV on lung IRI (LIRI) remain to be elucidated. Thus, we aimed to investigate the protective role and potential mechanisms of BV on LIRI.

Methods:

Lungs were isolated from Sprague-Dawley rats to establish an ex vivo LIRI model. After an initial 15 min stabilization period, the isolated lungs were subjected to ischemia for 60 min, followed by 90 min of reperfusion with or without BV treatment.

Results:

Lungs in the I/R group exhibited significant decrease in tidal volume (1.44 ± 0.23 ml/min in I/R group vs. 2.41 ± 0.31 ml/min in sham group; P < 0.001), lung compliance (0.27 ± 0.06 ml/cmH₂O in I/R group vs. 0.44 ± 0.09 ml/cmH₂O in sham group; P < 0.001; 1 cmH₂O=0.098 kPa), and oxygen partial pressure (PaO₂) levels (64.12 ± 12 mmHg in I/R group vs. 114 ± 8.0 mmHg in sham group; P < 0.001; 1 mmHg = 0.133 kPa). In contrast, these parameters in the BV group (2.27 ± 0.37 ml/min of tidal volume, 0.41 ± 0.10 ml/cmH₂O of compliance, and 98.7 ± 9.7 mmHg of PaO₂) were significantly higher compared with the I/R group (P = 0.004, P < 0.001, and P < 0.001, respectively). Compared to the I/R group, the contents of superoxide dismutase were significantly higher (47.07 ± 7.91 U/mg protein vs. 33.84 ± 10.15 U/mg protein; P = 0.005) while the wet/dry weight ratio (P < 0.01), methane dicarboxylic aldehyde (1.92 ± 0.25 nmol/mg protein vs. 2.67 ± 0.46 nmol/mg protein; P < 0.001), and adenosine triphosphate contents (297.05 ± 47.45 nmol/mg protein vs. 208.09 ± 29.11 nmol/mg protein; P = 0.005) were markedly lower in BV-treated lungs. Histological analysis revealed that BV alleviated LIRI. Furthermore, the expression of inflammatory cytokines (interleukin-1β, interleukin-6, and tumor necrosis factor-β) was downregulated and the expression of cyclooxygenase-2, inducible nitric oxide synthase, and Jun N-terminal kinase was significantly reduced in BV group (all P < 0.01 compared to I/R group). Finally, the apoptosis index in the BV group was significantly decreased (P < 0.01 compared to I/R group).

Conclusion:

BV protects lung IRI through its antioxidative, anti-inflammatory, and anti-apoptotic effects.

Exogenous Hydrogen Sulfide Postconditioning Protects Isolated Rat Hearts From Ischemia/Reperfusion Injury Through Sirt1/PGC-1α Signaling Pathway

Sirt1 is a highly conserved nicotinamide adenine dinucleotide (NAD(+)) dependent histone deacetylase which plays an important role in heart diseases. Studies performed with Sirt1 activators indicated that it protects cells from ischemia/ reperfusion (I/R) injury. The protective effects of H2S against I/R injury also have been recognized. Hence, the present study was designed to explore whether Sirt1/PGC-1α participates in the protection of exogenous H2S postconditioning against I/R injury in isolated rat hearts. Isolated rat hearts were subjected to 30 minutes of global ischemia followed by 60 minutes of reperfusion after 20 minutes of equilibrium. During this procedure, the hearts were exposed to NaHS (10 μmol/L) treatment in the absence or presence of the selective Sirt1 inhibitor EX-527 (10 μmol/L). NaHS exerted a protective effect on isolated rat hearts subjected to I/R, as shown by the improved expression of Sirt1/PGC-1α associated with restoration of Sirt1 nuclear localization, cardiac function, decreased myocardial infarct size, decreased myocardial enzyme release, and several biochemical parameters, including up-regulation of the ATP and SOD levels, and down-regulation of the MDA level. However, treatment with EX-527 could partially prevent the above effects of NaHS postconditioning. These results indicate that H2S confers protective effects against I/R injury through the activation of Sirt1/PGC1α.

Caffeic acid phenethyl ester attenuates ionize radiation-induced intestinal injury through modulation of oxidative stress, apoptosis and p38MAPK in rats

Caffeic acid phenyl ester (CAPE) is a potent anti-inflammatory agent and it can eliminate the free radicals. This study aimed to investigate the radioprotective effects of CAPE on X-ray irradiation induced intestinal injury in rats. Rats were intragastrically administered with 10 μmol/kg/d CAPE for 7 consecutive days before exposing them to a single dose of X-ray irradiation (9Gy) to abdomen. Rats were sacrificed 72 h after exposure to radiation. We found that pretreatment with CAPE effectively attenuated intestinal pathology changes, apoptosis, oxidative stress, bacterial translocation, the content of nitric oxide and myeloperoxidase as well as the concentration of plasma tumor necrosis factor-α. Pretreatment with CAPE also reversed the activation of p38MAPK and the increased expression of intercellular cell adhesion molecule-1 induced by radiation in intestinal mucosa. Taken together, these results suggest that pretreatment with CAPE could be a promising candidate for treating radiation-induced intestinal injury.

A unique disulfide bridge of the thermophilic xylanase SyXyn11 plays a key role in its thermostability

Based on the hyperthermostable family 11 xylanase (EvXyn11(TS)) gene sequence (EU591743), the gene Syxyn11 encoding a thermophilic xylanase SyXyn11 was synthesized with synonymous codons biasing towards Pichia pastoris. The homology alignment of primary structures among family 11 xylanases revealed that, at their N-termini, only SyXyn11 contains a disulfide bridge (Cys5-Cys32). This to some extent implied the significance of the disulfide bridge of SyXyn11 to its thermostability. To confirm the correlation between the N-terminal disulfide bridge and thermostability, a SyXyn11(C5T)-encoding gene, Syxyn11(C5T), was constructed by mutating the Cys5 codon of Syxyn11 to Thr5. Then, the genes for the recombinant xylanases, reSyXyn11 and reSyXyn11(C5T), were expressed in P. pastoris GS115, yielding xylanase activity of about 35 U per ml cell culture. Both xylanases were purified to homogeneity with specific activities of 363 and 344 U/mg, respectively. The temperature optimum and stability of reSyXyn11(C5T) decreased to 70 and 50°C from 85 and 80°C of reSyXyn11, respectively. There was no obvious change in pH characteristics.

Cloning, expression of a feruloyl esterase from Aspergillus usamii E001 and its applicability in generating ferulic acid from wheat bran

A cDNA gene (AufaeA), which encodes a mature polypeptide of the type-A feruloyl esterase from Aspergillus usamii E001 (abbreviated to AuFaeA), was cloned and heterologously expressed in Pichia pastoris GS115. One transformant, labeled as P. pastoris GSFaeA4-8, expressing the highest recombinant AuFaeA (reAuFaeA) activity of 10.76 U/ml was selected by the flask expression test. The expressed reAuFaeA was purified to homogeneity with an apparent molecular weight of 36.0 kDa by SDS-PAGE analysis, and characterized using the model substrate of methyl ferulate (MFA). The purified reAuFaeA was optimally active at pH 5.0 and 45 °C, and highly stable at pH 4.0–6.5 and 45 °C or below. Its activity was not significantly affected by metal ions tested and EDTA. The K  m and V  max of reAuFaeA towards MFA were 4.64 mM and 115.5 U/mg, respectively. High-performance liquid chromatography analysis showed that only 9.7 % of total alkali-extractable ferulic acid (FA) was released from destarched wheat bran by reAuFaeA alone. The released FA increased to 36.5 % when reAuFaeA was used together with a recombinant Aspergillus usamii GH family 11 xylanase A, indicating a synergistic interaction between them.

[The protective effect of glutamine on endotoxemic intestinal injury and expression of heme oxygenase-1 in rats]

OBJECTIVE

To investigate the protective effect of glutamine (Glu) pretreatment on intestinal injury induced by endotoxin and expression of heme oxygenase-1 (HO-1) in rats.

METHODS

Thirty-two male Sprague-Dawley (SD) rats were randomly divided into four groups (n=8 in each group): normal control group, model group, Glu group and Glu+zinc protoporphyrin (ZnPP) group. In model group, endotoxemia was produced by intraperitoneal injection of lipopolysaccharide (LPS, 10 mg/kg). In Glu group, the rats received intragastrically 1 g/kg of Glu 12 hours before LPS intraperitoneal injection. In Glu+ZnPP group, the rats received 1 g/kg of Glu by gavage 12 hours before LPS intraperitoneal injection and ZnPP 10 mmol/kg intravenously via tail vein 1 hour before LPS injection. The distal ileum was harvested in full thickness 12 hours after LPS injection. The myeloperoxidase (MPO) activity, tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) in the intestine were determined, the pathologic changes were observed and expressed in Chiu grade. The expression of HO-1 was evaluated by immunohistochemistry method.

RESULTS

Compared with normal control group, the Chiu grade, MPO activity, the content of TNF-α and IL-10 were significantly increased in model group [Chiu grade: 3.3±0.4 vs. 1.1±0.6, MPO activity (U/g): 0.40±0.08 vs. 0.26±0.07, TNF-α (ng/g): 25.2±6.9 vs. 6.5±2.8, IL-10 (ng/g): 27.6±10.2 vs. 5.7±2.9, all P<0.01], and the expression of HO-1 was decreased. Compared with model group, the Chiu grade, MPO activity, the content of TNF-α in Glu group were significantly decreased [Chiu grade: 1.6±0.5 vs. 3.3±0.4, MPO activity (U/g): 0.25±0.05 vs. 0.40±0.08, the content of TNF-α (ng/g): 13.4±3.2 vs. 25.2±6.9, all P<0.01], while the level of IL-10 (ng/g) elevated (47.3±5.5 vs. 27.6±10.2, P<0.01), and the expression of HO-1 was increased. There was no difference in above mentioned indexes between model group and Glu+ZnPP group.

CONCLUSION

Glu pretreatment significantly ameliorates the expression of HO-1 of intestinal tissue induced by LPS in rats, and intestinal mucosa is protected with alleviation of inflammatory reaction in intestinal tract.

Protective effect of heme oxygenase-1 on lung injury induced by erythrocyte instillation in rats

BACKGROUND

Intratracheal instillation of blood induces self-repaired acute lung injury. However, the mechanism of repair has been unclear. Heme-oxygenase (HO)-1, which catalyzes heme breakdown, acts as an inducible defense against oxidative stress and plays an important role in inflammation. The objective of this study was to test the role of HO-1 in lung injury caused by intratracheal instillation of red cells.

METHODS

Forty healthy, male Sprague-Dawley rats were randomly divided into five groups: normal group, saline group, erythrocyte group, erythrocyte+zinc-protoporphyrin (ZnPP, HO-1 inhibitor) group and saline+ZnPP group. At 2 days after intratracheal instillation of red cells, lung tissues and lavage samples were isolated for biochemical determinations and histological measurements.

RESULTS

Histological analysis revealed that administration of ZnPP worsened the acute lung injury induced by instilled erythrocytes. HO-1 was over-expressed in the erythrocyte group and in the erythrocyte + ZnPP group. Compared with the erythrocyte + ZnPP group, the levels of total protein, lactate dehydrogenase and tumor necrosis factor-alpha in the lavage were lower (P < 0.01), while the level of interleukin-10 was higher in the erythrocyte group (P < 0.01).

CONCLUSION

HO-1 protects against erythrocyte-induced inflammatory injury in lung.

[Effects of L. lactis recombinant heme oxygenase-1 gene on the intestinal barrier in rats with hemorrhagic shock]

OBJECTIVE

To evaluate the effect of gavage of L. lactis recombinant heme oxygenase-1 (HO-1) gene on protection of the intestinal mucosa and the inflammation of lower intestine during hemorrhagic shock.

METHODS

A model of hemorrhagic shock was reproduced in 30 SD healthy male rats. They were randomly divided into the L. lactis recombinant HO-1 gene group (HO group, n=10), L. lactis group (LL group, n=10), and glutamine group (Glu group, n=10). Glu was gavaged 6 hours and other agents were gavaged 24 hours before the experiment. Samples were collected 1 hour after hemorrhagic shock and fluid resuscitation. The mortality, mean arterial pressure (MAP) during hemorrhagic shock and fluid resuscitation, myeloperoxidase (MPO) activity, the pathological changes, and the contents of HO-1, tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) of the lower intestine were determined immunohistochemically and compared.

RESULTS

When the results of HO group were compared with Glu and LL groups, the mortality was significantly decreased in the former (both P<0.05). In HO group, MAP values at 5, 10, 20 and 30 minutes after fluid resuscitation were significantly elevated (all P<0.05). Compared with LL group, the gray levels of IL-10 and HO-1 in HO group and Glu group were significantly increased (all P<0.05). Compared with Glu group, the gray level of HO-1 was significantly increased in HO group (P<0.05). There were no significant differences in the gray levels of TNF-alpha among three groups. The Chiu's grade of HO group [(1.41+/-0.28) scores] was significantly lower than those of LL group and Glu group [(1.93+/-0.49) scores and (1.75+/-0.58) scores, respectively, both P<0.05].

CONCLUSION

The L. lactis recombinant HO-1 has the virtue to deliver HO-1 activity in rats with hemorrhagic shock, which is beneficial for the maintenance of intestinal barrier and anti-inflammation response of the lower intestine.

[Screening for low-density lipoprotein receptor gene mutations in familial hypercholesterolemia Chinese]

OBJECTIVE

To screen the mutations of low-density lipoprotein receptor (LDLR) gene in Chinese familial hypercholesterolemia (FH) patients.

METHODS

7 patients with clinical phenotype of homozygous FH and their parents were investigated for mutations in all the eighteen exons of LDLR gene. Screening was carried out using PCR-SSCP and direct DNA sequencing and LDLR gene mutation database was searched to identify the alteration. In addition, the apolipoprotein B gene (apo B) was screened for known mutations (R3500Q) that caused familial defective apo B100 (FDB) with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Nine mutations in the LDLR gene were identified in the FH patients. All the mutations except C255R have not been published in the LDLR gene mutation database. No mutation of apo B100 (R3500Q) was observed.

CONCLUSIONS

Chinese FH patients may have specific spectrum and regional difference of LDLR gene mutations. Apolipoprotein B-100 gene mutation might not be the main cause of hypercholesterolemia patients in China.

Detection and preliminary studies of small double capsid virus

This article reports the detection of small double capsid virus and results of preliminary studies on its morphology, serology and relationship to gastroenteritis. A kind of small virus particles with morphological characteristics was found in fecal samples of 3 of 23 infants with autumn gastroenteritis. The average diameter of this virus particles is 34.1 +/- 1.1 nm, possessing core, double capsids and spoke-like capsomers. It can be differentiated from other viruses in morphology. Correlated antigenicity exists among 3 strains of the virus but not among other studied viruses and this virus. The titer of the antibody to small double capsid virus in convalescent phase-sera of 2 patients was more than 4-fold as high as that in control sera. This virus was absent in fecal samples of recovered patients as well as in those of normal infants. These show that small "double layer like" capsid virus might be one of the etiological agents of acute gastroenteritis.