Tangeretin ameliorates bisphenol induced hepatocyte injury by inhibiting inflammation and oxidative stress

Bisphenol A (BPA) is an industrial toxicant that can potentially damage the liver. Tangeretin (TGN) is a natural flavonoid that displays various pharmacological activities. This experiment was carried out to evaluate the protective effects of TGN against BPA-induced hepatic impairment in the male albino rat. Twenty-four male albino rats were equally divided into four different groups: control, BPA (100 mg/kg), BPA + TGN (100 mg/kg + 50 mg/kg) and TGN (50 mg/kg). BPA exposure significantly decreased the activities of catalase (CAT), superoxidase dismutase (SOD), peroxidase (POD), glutathione reductase (GSR), glutathione S-transferase (GST), and glutathione (GSH) content while substantially increasing the thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H₂O₂) levels. A substantial increase in the levels of alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST) was also observed in BPA treated rats. Moreover, BPA significantly increased the inflammatory markers, including tumor necrosis factor-α (TNF-α), nuclear factor kappa-B (NF-κB), Interleukin-6 (IL-6), Interleukin-1β (IL-1β)levels, cyclooxygenase-2 (COX-2) activity, and histopathological damages. However, co-treatment with TGN efficiently minimized the BPA-induced biochemical, inflammatory, and histopathological impairments in rat liver. The present study shows that TNG has significant potential to avert BPA-induced liver damage to its antioxidant and anti-inflammatory properties.     

Artesunate relieves acute kidney injury through inhibiting macrophagic Mincle-mediated necroptosis and inflammation to tubular epithelial cell

Artesunate is a widely used derivative of artemisinin for malaria. Recent researches have shown that artesunate has a significant anti-inflammatory effect on many diseases. However, its effect on acute kidney injury with a significant inflammatory response is not clear. In this study, we established a cisplatin-induced AKI mouse model and a co-culture system of BMDM and tubular epithelial cells (mTEC) to verify the renoprotective and anti-inflammatory effects of artesunate on AKI, and explored the underlying mechanism. We found that artesunate strongly down-regulated the serum creatinine and BUN levels in AKI mice, reduced the necroptosis of tubular cells and down-regulated the expression of the tubular injury molecule Tim-1. On the other hand, artesunate strongly inhibited the mRNA expression of inflammatory cytokines (IL-1β, IL-6 and TNF-α), protein levels of inflammatory signals (iNOS and NF-κB) and necroptosis signals (RIPK1, RIPK3 and MLKL) in kidney of AKI mouse. Notably, the co-culture system proved that Mincle in macrophage can aggravate the inflammation and necroptosis of mTEC induced by LPS, and artesunate suppressed the expression of Mincle in macrophage of kidney in AKI mouse. Overexpression of Mincle in BMDM restored the damage and necroptosis inhibited by artesunate in mTEC, indicating Mincle in macrophage is the target of artesunate to protect tubule cells in AKI. Our findings demonstrated that artesunate can significantly improve renal function in AKI, which may be related to the inhibition of Mincle-mediated macrophage inflammation, thereby reducing the damage and necroptosis to tubular cells that provide new option for the treatment of AKI.     

Severe Vitamin E deficiency exacerbates acute hyperoxic lung injury associated with increased oxidative stress and inflammation

Hyperoxia causes acute lung injury along with an increase of oxidative stress and inflammation. It was hypothesized that vitamin E deficiency might exacerbate acute hyperoxic lung injury. This study used alpha-tocopherol transfer protein knockout (alpha-TTP KO) mice fed a vitamin E-deficient diet (KO E(-) mice) as a model of severe vitamin E deficiency. Compared with wild-type (WT) mice, KO E(-) mice showed a significantly lower survival rate during hyperoxia. After 72 h of hyperoxia, KO E(-) mice had more severe histologic lung damage and higher values of the total cell count and the protein content of bronchoalveolar lavage fluid (BALF) than WT mice. IL-6 mRNA expression in lung tissue and the levels of 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)) in both lungs and BALF were higher in KO E(-) mice than in WT mice. It was concluded that severe vitamin E deficiency exacerbates acute hyperoxic lung injury associated with increased oxidative stress or inflammation.     

Severe Vitamin E deficiency exacerbates acute hyperoxic lung injury associated with increased oxidative stress and inflammation

Hyperoxia causes acute lung injury along with an increase of oxidative stress and inflammation. It was hypothesized that vitamin E deficiency might exacerbate acute hyperoxic lung injury. This study used α-tocopherol transfer protein knockout (α-TTP KO) mice fed a vitamin E-deficient diet (KO E(-) mice) as a model of severe vitamin E deficiency. Compared with wild-type (WT) mice, KO E(-) mice showed a significantly lower survival rate during hyperoxia. After 72 h of hyperoxia, KO E(-) mice had more severe histologic lung damage and higher values of the total cell count and the protein content of bronchoalveolar lavage fluid (BALF) than WT mice. IL-6 mRNA expression in lung tissue and the levels of 8-iso-prostaglandin F_2α (8-iso-PGF_2α) in both lungs and BALF were higher in KO E(-) mice than in WT mice. It was concluded that severe vitamin E deficiency exacerbates acute hyperoxic lung injury associated with increased oxidative stress or inflammation.     

Protective effect of Apremilast against LPS-induced acute lung injury via modulation of oxidative stress and inflammation

Lung injuries are attributed due to exposure to Drugs or chemicals. One of the important challenging situations for the clinicians is to manage treatments of different diseases with acute lung injury (ALI). The objective of this study was to investigate the possible protective mechanisms and action of a novel Phosphodiesterase-4 inhibitor “Apremilast” (AP) in lipopolysaccharide (LPS)-induced lung injury. Blood sample from each animals were collected in a vacuum blood collection tube. The rat lungs were isolated for oxidative stress assessment, western blot analysis and their mRNA expressions using RT-PCR. Exposure of LPS in rats causes significant increase in oxidative stress, activates the pro-inflammatory cytokines release like tissue necrotic factor-alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6), modulated gene expression, protein expression and histopathological changes which were reversed by administration of AP. Finding of the research enlighten the protective role of AP against LPS-induced ALI.     

低氧预处理通过上调钙网蛋白表达减轻大鼠心肌细胞氧化应激损伤

本文旨在探讨钙网蛋(calreticulin,CRT)是否参与低氧预处理(hypoxic preconditioning,HPC)对心肌细胞氧化应激损伤的保护及其信号转导过程.将原代培养的Sprague.Dawley乳鼠心肌细胞随机分为8组:氧化应激(H2O2)组、短暂低氧(HPC)组、HPC H202组、SB203580(p38 MAPK特异性抑制剂) HPC H2O2组、干扰心肌细胞CRT表达的反义寡核苷酸(antiscnse oligodeoxynucleotides,AS)组、AS H2O2组、AS HPC H202组和对照组,以细胞存活率、乳酸脱氢酶(1actate dehydrogenase,LDH)漏出及流式细胞术检测细胞损伤情况;采用RT-PCR和Western blot分别检测CRT表达和p38MAPK磷酸化水平.结果表明:(1)HPC可减轻氧化应激损伤,与H202组比较,HPC H2O2组细胞存活率增高18.0%,细胞凋亡率和LDH漏出分别降低19.4%和53.0%(均P<0.05);HPC前以SB203580预孵育可消除HPC保护作用,与HPC H202组相比,SB203580 HPC H2O2组细胞凋亡率和LDH漏出分别增高13.1%和96.0%,存活率降低7.3%(均P<0.05);(2)氧化应激明显上调CRT表达(H202组较对照组高7.1倍,P<0.05);HPC也诱导CRT表达上调(HPC组较对照组高2.4倍,P<0.05),但上调程度较H2O2组低59%(P<0.05);即HPC可减轻氧化应激诱导的CRT过表达:(3)AS干扰CRT表达后,HPC保护作用降低,相关性分析显示HPC诱导的CRT适度表达与细胞存活率呈正相关(r=0.8023,P<0.05);(4)HPC前SB203580预孵育可抑制CRT表达上调(分别较HPC H2O2组和HPC组低75%和53%,均P<0.05).上述结果提示,HPC可能通过p38 MAPK信号途径诱导CRT表达上调,减轻心肌细胞氧化应激损伤.     

Isoliquiritigenin prevents hyperglycemia-induced renal injuries by inhibiting inflammation and oxidative stress via SIRT1-dependent mechanism

Diabetic nephropathy (DN) as a global health concern is closely related to inflammation and oxidation. Isoliquiritigenin (ISL), a natural flavonoid compound, has been demonstrated to inhibit inflammation in macrophages. Herein, we investigated the effect of ISL in protecting against the injury in STZ-induced type 1 DN and in high glucose-induced NRK-52E cells. In this study, it was revealed that the administration of ISL not only ameliorated renal fibrosis and apoptosis, but also induced the deterioration of renal function in diabetic mice. Mediated by MAPKs and Nrf-2 signaling pathways, respectively, upstream inflammatory response and oxidative stress were neutralized by ISL in vitro and in vivo. Moreover, as further revealed by the results of molecular docking, sirtuin 1 (SIRT1) binds to ISL directly, and the involvement of SIRT1 in ISL-mediated renoprotective effects was confirmed by studies using in vitro models of SIRT1 overexpression and knockdown. In summary, by reducing inflammation and oxidative stress, ISL has a significant pharmacological effect on the deterioration of DN. The benefits of ISL are associated with the direct binding to SIRT1, the inhibition of MAPK activation, and the induction of Nrf-2 signaling, suggesting the potential of ISL for DN treatment.Subject terms: Pharmacology, Molecular biology     

Astragaloside IV prevents acute kidney injury in two rodent models by inhibiting oxidative stress and apoptosis pathways

Oxidative stress and apoptosis play key role in the pathogenesis of acute kidney injury (AKI). We hypothesize that Astragaloside IV(AS-IV) prevents AKI through inhibiting oxidative stress and apoptosis. The rats were divided into sham control, saline-,vehicle-, or AS-IV-treated groups. AS-IV (20 mg/kg) was orally administered once daily to the rats for 7 consecutive days before terminating the experiments. In ischemia-induced AKI model, experimental rats were subjected to bilateral clamping of the renal arteries for 45 min, followed by reperfusion for 24 h. In contrast-induced AKI model, iopamidol (2.9 g iodine/kg) was administered intravenously into the rats. Renal function, histopathology, oxidative stress and apoptosis were evaluated in these models. Pretreatment with AS-IV significantly decreased blood urea nitrogen, serum creatinine, cystatin C and neutrophil gelatinase-associated lipocalin levels, as well as urinary kidney injury molecule-1 level and tubular injury. AS-IV also reduced oxidative stress and tubular cell apoptosis. The p38 mitogen-activated protein kinase phosphorylation and caspase-3 activity were elevated in kidney tissues from AKI rats, accompanied by an increase in Bax expression and a decrease in Bcl-2 expression at mRNA and protein levels. These changes were prevented by AS-IV pretreatment. Therefore, AS-IV can be developed as a novel therapeutic approach to prevent AKI through targeting inhibition of oxidative stress and apoptosis pathways.     

NEAT1 contributes to ox-LDL-induced inflammation and oxidative stress in macrophages through inhibiting miR-128

Long noncoding RNAs (lncRNA) have been recognized as significant regulators in the progression of atherosclerosis (AS). Oxidized low-density lipoprotein (ox-LDL) can induce macrophage inflammation and oxidative stress, that serves important roles in AS. However, the exact function of lncRNA NEAT1 and its possible molecular mechanism in AS remain unclear. Here, we concentrated on the roles and molecular mechanisms of NEAT1 in AS development. In our current study, we observed that NEAT1 was elevated by ox-LDL in a dose-dependent and time-dependent manner. RAW264.7 cell survival was greatly enhanced, and cell apoptosis was significantly inhibited by LV-shNEAT1 transfection. In addition, knockdown of NEAT1 in RAW264.7 cells repressed CD36 expression and foam cell formation while NEAT1 overexpression shown an opposite process. Moreover, NEAT1 downregulation inhibited inflammation molecules including IL-6, IL-1β, and TNF-α. Meanwhile, silencing of NEAT1 can also suppress reactive oxygen species (ROS) and malondialdehyde (MDA) levels with an enhancement of superoxide dismutase (SOD) activity in RAW264.7 cells. MicroRNAs are some short RNAs, and they can regulate multiple biological functions in many diseases including AS. Here, we found that miR-128 expression was remarkably decreased in ox-LDL-incubated RAW264.7 cells. Interestingly, miR-128 mimics was able to reverse AS-correlated events induced by overexpression of NEAT1. By using bioinformatics analysis, miR-128 was predicted as a target of NEAT1 and the correlation between them was validated in our study. Taken these together, it was implied that NEAT1 participated in ox-LDL-induced inflammation and oxidative stress in AS development through sponging miR-128.     

C-type natriuretic peptide ameliorates ischemia/reperfusion-induced acute kidney injury by inhibiting apoptosis and oxidative stress in rats

Aims

Although atrial natriuretic peptide has been shown to attenuate ischemia–reperfusion (IR)-induced kidney injury, the effect of natriuretic peptide receptor (NPR)-B activation on IR-induced acute kidney injury is not well documented. The purpose of the present study was to identify the effect of C-type natriuretic peptide (CNP), a selective activator of NPR-B, on the IR-induced acute kidney injury and its mechanisms involved.

Main methods

Unilaterally nephrectomized rats were insulted by IR in their remnant kidney, and they were randomly divided into three groups: sham, vehicle + IR, and CNP + IR groups. CNP (0.2 μg/kg/min) was administered intravenously at the start of a 45-min renal ischemia for 2 h. Rats were then killed 24 h after I/R, and the blood and tissue samples were collected to assess renal function, histology, TUNEL assay, and Western blot analysis of kidney Bax and Bcl-2 expressions.

Key findings

The levels of blood urea nitrogen and serum creatinine were significantly increased in rats after IR compared with vehicle-treated rats. IR elevated apoptosis, Bcl-2/Bax ratio, TUNEL positivity, oxidative stress parameters, malondialdehyde concentration, and superoxide dismutase activity. IR also induced epithelial desquamation of the proximal tubules and glomerular shrinkage. CNP significantly attenuated the IR-induced increase in BUN and serum creatinine. Furthermore, CNP restored the suppressed renal cyclic guanosine 3′ 5′-monophosphate levels caused by IR insult.

Significance

Study findings suggest that CNP could ameliorate IR-induced acute kidney injury through inhibition of apoptotic and oxidative stress pathways, possibly through NPR-B-cGMP signaling.     

Cytokine-mediated inflammation in acute lung injury

Clinical acute lung injury (ALI) is a major cause of acute respiratory failure in critically ill patients. There is considerable experimental and clinical evidence that pro- and anti-inflammatory cytokines play a major role in the pathogenesis of inflammatory-induced lung injury from sepsis, pneumonia, aspiration, and shock. A recent multi-center clinical trial found that a lung-protective ventilatory strategy reduces mortality by 22% in patients with ALI. Interestingly, this protective ventilatory strategy was associated with a marked reduction in the number of neutrophils and the concentration of pro-inflammatory cytokines released into the airspaces of the injured lung. Further research is needed to establish the contribution of cytokines to both the pathogenesis and resolution of ALI.     

Chicoric acid ameliorate inflammation and oxidative stress in Lipopolysaccharide and d-galactosamine induced acute liver injury

Chicoric acid is polyphenol of natural plant and has a variety of bioactivity. Caused by various kinds of stimulating factors, acute liver injury has high fatality rate. The effect of chicoric acid in acute liver injury induced by Lipopolysaccharide (LPS) and d -galactosamine (d -GalN) was investigated in this study. The results showed that CA decreased the aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum and reduced the mortality induced by LPS/d -GalN. CA can restrain mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) to alleviate inflammation. Meanwhile, the results indicated CA can active nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway with increasing the level of AMP-activated protein kinase (AMPK). And with the treatment of CA, protein levels of autophagy genes were obvious improved. The results of experiments indicate that CA has protective effect in liver injury, and the activation of AMPK and autophagy may make sense.     

Normothermic machine perfusion attenuates hepatic ischaemia-reperfusion injury by inhibiting CIRP-mediated oxidative stress and mitochondrial fission

Extracellular cold-inducible RNA-binding protein (CIRP) is a proinflammatory mediator that aggravates ischaemia-reperfusion injury (IRI). Normothermic machine perfusion (NMP) could effectively alleviate the IRI of the liver, but the underlying mechanism remains to be explored. We show that human DCD livers secreted a large amount of CIRP during static cold storage (CS), which is released into the circulation after reperfusion. The expression of CIRP was related to postoperative IL-6 levels and liver function. In a rat model, the CIRP expression was upregulated during warm ischaemia and cold storage. Then, rat DCD livers were preserved using CS, hypothermic oxygenated machine perfusion (HOPE) and NMP. C23, a CIRP inhibitor, was administrated in the HOPE group. Compared with CS, NMP significantly inhibited CIRP expression and decreased oxidative stress by downregulating NADPH oxidase and upregulating UCP2. NMP markedly inhibited the mitochondrial fission-related proteins Drp-1 and Fis-1. Further, NMP increased the mitochondrial biogenesis-related protein, TFAM. NMP significantly reduced inflammatory reactions and apoptosis after reperfusion, and NMP-preserved liver tissue had higher bile secretion and ICG metabolism compared to the CS group. Moreover, C23 administration attenuated IRI in the HOPE group. Additionally, HL-7702 cells were stimulated with rhCIRP and C23. High rhCIRP levels increased oxidative stress and apoptosis. In summary, NMP attenuates the IRI of DCD liver by inhibiting CIRP-mediated oxidative stress and mitochondrial fission.     

Alcohol worsens acute lung injury by inhibiting alveolar sodium transport through the adenosine A1 receptor

Objective

Alcohol intake increases the risk of acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) and is associated with poor outcomes in patients who develop these syndromes. No specific therapies are currently available to treat or decrease the risk of ARDS in patients with alcoholism. We have recently shown increased levels of lung adenosine inhibit alveolar fluid clearance, an important predictor of outcome in patients with ARDS. We hypothesized that alcohol might worsen lung injury by increasing lung adenosine levels, resulting in impaired active Na⁺ transport in the lung.

Methods

We treated wild-type mice with alcohol administered i.p. to achieve blood alcohol levels associated with moderate to severe intoxication and measured the rate of alveolar fluid clearance and Na,K-ATPase expression in peripheral lung tissue and assessed the effect of alcohol on survival during exposure to hyperoxia. We used primary rat alveolar type II cells to investigate the mechanisms by which alcohol regulates alveolar Na⁺ transport.

Results

Exposure to alcohol reduced alveolar fluid clearance, downregulated Na,K-ATPase in the lung tissue and worsened hyperoxia-induced lung injury. Alcohol caused an increase in BAL fluid adenosine levels. A similar increase in lung adenosine levels was observed after exposure to hyperoxia. In primary rat alveolar type II cells alcohol and adenosine decreased the abundance of the Na,K-ATPase at the basolateral membrane via a mechanism that required activation of the AMPK.

Conclusions

Alcohol decreases alveolar fluid clearance and impairs survival from acute lung injury. Alcohol induced increases in lung adenosine levels may be responsible for reduction in alveolar fluid clearance and associated worsening of lung injury.     

Dipeptidyl peptidase-4 inhibition prevents lung injury in mice under chronic stress via the modulation of oxidative stress and inflammation

Exposure to chronic psychosocial stress is a risk factor for various pulmonary diseases. In view of the essential role of dipeptidyl peptidase 4 (DPP4) in animal and human lung pathobiology, we investigated the role of DPP4 in stress-related lung injury in mice. Eight-week-old male mice were randomly divided into a non-stress group and a 2-week immobilization stress group. Non-stress control mice were left undisturbed. The mice subjected to immobilized stress were randomly assigned to the vehicle or the DPP4 inhibitor anagliptin for 2 weeks. Chronic stress reduced subcutaneous and inguinal adipose volumes and increased blood DPP4 levels. The stressed mice showed increased levels in the lungs of genes and/or proteins related to oxidative stress (p67^phox, p47^phox, p22^phox and gp91^phox), inflammation (monocyte chemoattractant protein-1, vascular cell adhesion molecule-1, and intracellular adhesion molecule-1), apoptosis (caspase-3, -8, -9), senescence (p16^INK4A, p21, and p53) and proteolysis (matrix metalloproteinase-2 to -9, cathepsin S/K, and tissue inhibitor of matrix metalloproteinase-1 and -2), and reduced levels of eNOS, Sirt1, and Bcl-2 proteins; and these effects were reversed by genetic and pharmacological inhibitions of DPP4. We then exposed human umbilical vein endothelial cells in vitro to hydrogen peroxide; anagliptin treatment was also observed to mitigate oxidative and inflammatory molecules in this setting. Anagliptin can improve lung injury in stressed mice, possibly by mitigating vascular inflammation, oxidative stress production, and proteolysis. DPP4 may become a new therapeutic target for chronic psychological stress-related lung disease in humans and animals.     

Activation of Src-dependent Smad3 signaling mediates the neutrophilic inflammation and oxidative stress in hyperoxia-augmented ventilator-induced lung injury

Background

Mechanical ventilation and concomitant administration of hyperoxia in patients with acute respiratory distress syndrome can damage the alveolar epithelial and capillary endothelial barrier by producing inflammatory cytokines and reactive oxygen species. The Src tyrosine kinase and Smad3 are crucial inflammatory regulators used for ventilator-induced lung injury (VILI). The mechanisms regulating interactions between high-tidal-volume mechanical ventilation, hyperoxia, and acute lung injury (ALI) are unclear. We hypothesized that high-tidal-volume mechanical stretches and hyperoxia augment lung inflammation through upregulation of the Src and Smad3 pathways.

Methods

Wild-type or Src-deficient C57BL/6 mice, aged between 6 and 8 weeks, were exposed to high-tidal-volume (30 mL/kg) ventilation with room air or hyperoxia for 1–4 h after 2-mg/kg Smad3 inhibitor (SIS3) administration. Nonventilated mice were used as control subjects.

Results

We observed that the addition of hyperoxia to high-tidal-volume mechanical ventilation further induced microvascular permeability, neutrophil infiltration, macrophage inflammatory protein-2 and matrix metalloproteinase-9 (MMP-9) production, malondialdehyde, nicotinamide adenine dinucleotide phosphate oxidase activity, MMP-9 mRNA expression, hypoxemia, and Src and Smad3 activation (P < 0.05). Hyperoxia-induced augmentation of VILI was attenuated in Src-deficient mice and mice with pharmacological inhibition of Smad3 activity by SIS3 (P < 0.05). Mechanical ventilation of Src-deficient mice with hyperoxia further reduced the activation of Smad3.

Conclusions

Our data suggest that hyperoxia-increased high-tidal-volume ventilation-induced ALI partially depends on the Src and Smad3 pathways.     

The role of oxidative stress in lung injury induced by cigarette smoke

Oxidative stress is a damaging process resulting from an imbalance between excessive generation of oxidant compounds and insufficient antioxidant defence mechanisms. Oxidative stress plays a crucial role in the initiation and progression of cigarette smoke-induced lung injury, deterioration in lung functions, and development of chronic obstructive pulmonary disease (COPD). In smokers and in patients with COPD, the increased oxidant burden derives from cigarette smoke per se, and from activated inflammatory cells releasing enhanced amounts of reactive oxygen and nitrogen species (ROS, RNS, respectively). Although mild oxidative stress resulting from cigarette smoking leads to the upregulation of the antioxidative enzymes synthesis in the lungs, high levels of ROS and RNS observed in patients with COPD overwhelm the antioxidant enzymes capacities, resulting in oxidant-mediated lung injury and cell death. In addition, depletion of antioxidative systems in the systemic circulation was consistently observed in such patients. The imbalance between the generation of ROS/RNS and antioxidant capacities — the state of “oxidative stress” — is one of the major pathophysiologic hallmarks in the development of COPD. Detrimental effects of oxidative stress include impairment of membrane functions, inactivation of membrane-bound receptors and enzymes, and increased tissue permeability. In addition, oxidative stress aggravates the inflammatory processes in the lungs, and contributes to the worsening of the protease-antiprotease imbalance. Several markers of oxidative stress, such as increases in lipid peroxidation products and reductions in glutathione peroxidase activity, have been shown to be related to the reductions in pulmonary functions. In the present article we review the current knowledge about the vicious cycle of cigarette smoking, oxidative stress, and inflammation in the pathogenesis of COPD.     

Activation of PAR2 promotes high-fat diet-induced renal injury by inducing oxidative stress and inflammation

A high-fat diet (HFD) is a major risk factor for chronic kidney disease. Although HFD promotes renal injury, characterized by increased inflammation and oxidative stress leading to fibrosis, the underlying mechanism remains elusive. Here, we investigated the role and mechanism of protease-activating receptor 2 (PAR2) activation during HFD-induced renal injury in C57/BL6 mice. HFD for 16 weeks resulted in kidney injury, manifested by increased blood levels of blood urea nitrogen, increased levels of oxidative stress with inflammation, and structural changes in the kidney tubules. HFD-fed kidneys showed elevated PAR2 expression level in the tubular epithelial region. To elucidate the role of PAR2, PAR2 knockout mice and their littermates were administered HFD. PAR2 deficient kidneys showed reduced extent of renal injury. PAR2 deficient kidneys showed significantly decreased levels of inflammatory gene expression and macrophage infiltration, followed by reduced accumulation of extracellular matrix proteins. Using NRK52E kidney epithelial cells, we further elucidated the mechanism and role of PAR2 activation during renal injury. Palmitate treatment increased PAR2 expression level in NRK52E cells and scavenging of oxidative stress blocked PAR2 expression. Under palmitate-treated conditions, PAR2 agonist-induced NF-κB activation level was higher with increased chemokine expression level in the cells. These changes were attenuated by the depletion of oxidative stress. Taken together, our results suggest that HFD-induced PAR2 activation is associated with increased levels of renal oxidative stress, inflammatory response, and fibrosis.     

Immunotargeting of catalase to the pulmonary endothelium alleviates oxidative stress and reduces acute lung transplantation injury

Vascular immunotargeting may facilitate the rapid and specific delivery of therapeutic agents to endothelial cells. We investigated whether targeting of an antioxidant enzyme, catalase, to the pulmonary endothelium alleviates oxidative stress in an in vivo model of lung transplantation. Intravenously injected enzymes, conjugated with an antibody to platelet-endothelial cell adhesion molecule-1, accumulate in the pulmonary vasculature and retain their activity during prolonged cold storage and transplantation. Immunotargeting of catalase to donor rats augments the antioxidant capacity of the pulmonary endothelium, reduces oxidative stress, ameliorates ischemia-reperfusion injury, prolongs the acceptable cold ischemia period of lung grafts, and improves the function of transplanted lung grafts. These findings validate the therapeutic potential of vascular immunotargeting as a drug delivery strategy to reduce endothelial injury. Potential applications of this strategy include improving the outcome of clinical lung transplantation and treating a wide variety of endothelial disorders.     

Neuregulin-1 alleviate oxidative stress and mitigate inflammation by suppressing NOX4 and NLRP3/caspase-1 in myocardial ischaemia-reperfusion injury

Neuregulin-1 (NRG-1) is reported to be cardioprotective through the extracellular-regulated protein kinase (ERK) 1/2 pathway in myocardial ischaemia-reperfusion injury (MIRI). NOX4-induced ROS activated NLRP3 inflammasome and exacerbates MIRI. This study aims to investigate whether NRG-1 can suppress NOX4 by ERK1/2 and consequently inhibit the NLRP3/caspase-1 signal in MIRI. The myocardial infarct size (IS) was measured by TTC-Evans blue staining. Immunohistochemical staining, real-time quantitative PCR (RT-qPCR) and Western blotting were used for detection of the factors, such as NOX4, ERK1/2, NLRP3, caspase-1 and IL-1β .The IS in the NRG-1 (3 μg/kg, intravenous) group was lower than that in the IR group. Immunohistochemical analysis revealed NRG-1 decreased 4HNE and NOX4. The RT-qPCR and Western blot analyses revealed that NRG-1 mitigated the IR-induced up-regulation of NOX4 and ROS production. Compared with the IR group, the NRG-1 group exhibited a higher level of P-ERK1/2 and a lower level of NLRP3. In the Langendorff model, PD98059 inhibited ERK1/2 and up-regulated the expression of NOX4, NLRP3, caspase-1 and IL-1β, which exacerbated oxidative stress and inflammation. In conclusion, NRG-1 can reduce ROS production by inhibiting NOX4 through ERK1/2 and inhibit the NLRP3/caspase-1 pathway to attenuate myocardial oxidative damage and inflammation in MIRI.