Tat-biliverdin reductase A inhibits inflammatory response by regulation of MAPK and NF-κB pathways in Raw 264.7 cells and edema mouse model

Ginsenoside Rb3 Inhibits Oxidative Stress and Alleviates Experimental Periodontitis in Rats

OBJECTIVE

This study investigated the anti-inflammatory and antioxidative effects of ginsenoside Rb3 on experimental periodontitis.

METHODS

Experimental periodontitis was established by ligating the maxillary first molars. After 21 days of Rb3 treatment, rats were sacrificed for micro-CT and H&E staining analysis and serum assay. qPCR detected the expression of inflammatory genes. IF detected MAPKs pathway activation in periodontal tissues. The effects were determined using LPS-induced RAW264.7 cells. Gene expression levels were determined by qPCR. Intracellular ROS generation was detected by DCFH-DA staining and flow cytometry. WB detected the activation of signaling pathways.

RESULTS

Rb3 inhibited oxidative stress in experimental periodontitis, showing reduced gingivitis and alveolar bone resorption on H&E staining and micro-CT, and reduced iNOS mRNA in rats. Colorimetric results showed that Rb3 increased serum SOD and GSH-Px activities and decreased MDA levels in rats. IF analysis showed that Rb3 inhibited P38, ERK, and JNK activation. Rb3 pretreatment significantly decreased iNOS and IL-6 mRNA expression and ROS in Raw264.7 cells. WB analysis demonstrated that Rb3 blocked the activation of P38 and ERK.

CONCLUSION

Rb3 inhibits the level of oxidative stress and attenuates gingivitis and alveolar bone resorption in rats via the MAPKs signaling pathway.

Anti-inflammatory effects of Olive (olea europaea L.) fruit extract in LPS-stimulated RAW264.7 cells via MAPK and NF-κB signal pathways

BACKGROUND

Olive is an evergreen tree of Oleaceae Olea with numerous bioactive components. While the anti-inflammatory properties of olive oil and the derivatives are well-documented, there remains a dearth of in-depth researches on the immunosuppressive effects of olive fruit water extract. This study aimed to elucidate the dose-effect relationship and underlying molecular mechanisms of olive fruit extract in mediating anti-inflammatory responses.

METHODS AND RESULTS

The impacts of olive fruit extract on the release of nitric oxide (NO), tumor necrosis factor (TNF-α), interleukins-6 (IL-6) and reactive oxygen species (ROS) were assessed in RAW264.7 cells induced by lipopolysaccharide (LPS). For deeper understanding, the expression of genes encoding inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α and IL-6 was quantitatively tested. Additionally, the expression patterns of MAPK and NF-κB pathways were further observed to analyze the action mechanisms. Results suggested that olive fruit extract (200, 500, 1000 µg/mL) markedly exhibited a dose-dependent reduction in the generation of NO, TNF-α, IL-6 and ROS, as well as the expression of correlative genes studied. The activation of ERK, JNK, p38, IκB-α and p65 were all suppressed when p65 nuclear translocation was further restricted by olive fruit extract in NF-κB and MAPK signal pathways.

CONCLUSIONS

Olive fruit extract targeted imposing restrictions on the signal transduction of key proteins in NF-κB and MAPK pathways, and thereby lowered the level of inflammatory mediators, which put an enormous hindrance to inflammatory development. Accordingly, it is reasonable to consider olive fruit as a potent ingredient in immunomodulatory products.

Nicotinamide phosphoribose transferase facilitates macrophage-mediated pulmonary fibrosis through the Sirt1-Smad7 pathway in mice

Pulmonary fibrosis is a challenging lung disease characterized by a bleak prognosis. A pivotal element in the progression of this disease is the dysregulated recruitment of macrophages. Nicotinamide phosphoribose transferase (NAMPT), secreted by alveolar epithelial cells and inflammatory cells, has been previously identified to influence macrophage inflammation in acute lung injury through the nicotinamide adenine dinucleotide (NAD) rescue synthesis pathway. Nonetheless, the exact role of NAMPT in the regulation of lung fibrosis is yet to be elucidated. In our research, we employed bleomycin (BLM) to induce pulmonary fibrosis in Namptflox/flox;Cx3cr1CreER mice, using Namptflox/flox mice as controls. Our findings revealed an augmented expression of NAMPT concurrent with a marked increase in the secretion of NAD and inflammatory cytokines such as IL-6, TNF-α, and TGF-β1 post-BLM treatment. Furthermore, an upsurge in NAMPT-positive macrophages was observed in the lungs of BLM-treated Namptflox/flox mice. Notably, a conditional knockout of NAMPT (NAMPT cKO) in lung macrophages curtailed the BLM-induced inflammatory responses and significantly mitigated pulmonary fibrosis. This was associated with diminished phospho-Sirt1 (p-Sirt1) expression levels and a concomitant rise in mothers against decapentaplegic homolog 7 (Smad7) expression in BLM-treated mouse lungs and murine RAW 264.7 macrophage cells. Collectively, our data suggests that NAMPT exacerbates macrophage-driven inflammation and pulmonary fibrosis via the Sirt1-Smad7 pathway, positioning NAMPT as a promising therapeutic target for pulmonary fibrosis intervention.

Cell-penetrating peptide-mediated delivery of therapeutic peptides/proteins to manage the diseases involving oxidative stress, inflammatory response and apoptosis

OBJECTIVES

Peptides and proteins represent great potential for modulating various cellular processes including oxidative stress, inflammatory response, apoptosis and consequently the treatment of related diseases. However, their therapeutic effects are limited by their inability to cross cellular barriers. Cell-penetrating peptides (CPPs), which can transport cargoes into the cell, could resolve this issue, as would be discussed in this review.

KEY FINDINGS

CPPs have been successfully exploited in vitro and in vivo for peptide/protein delivery to treat a wide range of diseases involving oxidative stress, inflammatory processes and apoptosis. Their in vivo applications are still limited due to some fundamental issues of CPPs, including nonspecificity, proteolytic instability, potential toxicity and immunogenicity.

SUMMARY

Totally, CPPs could potentially help to manage the diseases involving oxidative stress, inflammatory response and apoptosis by delivering peptides/proteins that could selectively reach proper intracellular targets. More studies to overcome related CPP limitations and confirm the efficacy and safety of this strategy are needed before their clinical usage.

Biliverdin reductase-A protein levels are reduced in type 2 diabetes and are associated with poor glycometabolic control

AIM

Biliverdin reductase-A (BVR-A) other than its canonical role in the degradation pathway of heme as partner of heme oxygenase-1 (HO1), has recently drawn attention as a protein with pleiotropic functions involved in insulin-glucose homeostasis. However, whether BVR-A expression is altered in type 2 diabetes (T2D) has never been evaluated.

MAIN METHODS

BVR-A protein levels were evaluated in T2D (n = 44) and non-T2D (n = 29) subjects, who underwent complete clinical workup and routine biochemistry. In parallel, levels HO1, whose expression is regulated by BVR-A as well as levels of tumor necrosis factor α (TNFα), which is a known repressor for BVR-A with pro-inflammatory properties, were also assessed.

KEY FINDINGS

BVR-A levels were significantly lower in T2D subjects than in non-T2D subjects. Reduced BVR-A levels were associated with greater body mass, systolic blood pressure, fasting blood glucose (FBG), glycated hemoglobin (HbA1c), triglycerides, transaminases and TNFα, and with lower high-density lipoprotein (HDL) levels. Lower BVR-A levels are associated with reduced HO1 protein levels and the multivariate analysis showed that BVR-A represented the main determinant of HO1 levels in T2D after adjustment. In addition, reduced BVR-A levels were able to predict the presence of T2D with AUROC = 0.69. for potential confounders.

SIGNIFICANCE

Our results demonstrate for the first time that BVR-A protein levels are reduced in T2D individuals, and that this alteration strictly correlates with poor glycometabolic control and a pro-inflammatory state. Hence, these observations reinforce the hypothesis that reduced BVR-A protein levels may represent a key event in the dysregulation of intracellular pathways finally leading to metabolic disorders.

Tat-thioredoxin 1 reduces inflammation by inhibiting pro-inflammatory cytokines and modulating MAPK signaling

Thioredoxin 1 (Trx1) serves a central role in redox homeostasis. It is involved in numerous other processes, including oxidative stress and apoptosis. However, to the best of our knowledge, the role of Trx1 in inflammation remains to be explored. The present study investigated the function and mechanism of cell permeable fused Tat-Trx1 protein in macrophages and a mouse model. Transduction levels of Tat-Trx1 were determined via western blotting. Cellular distribution of transduced Tat-Trx1 was determined by fluorescence microscopy. 2',7'-Dichlorofluorescein diacetate and TUNEL staining were performed to determine the production of reactive oxygen species and DNA fragmentation. Protein and gene expression were measured by western blotting and reverse transcription-quantitative PCR (RT-qPCR), respectively. Effects of skin inflammation were determined using hematoxylin and eosin staining, changes in ear weight and ear thickness, and RT-qPCR in ear edema animal models. Transduced Tat-Trx1 inhibited lipopolysaccharide-induced cytotoxicity and activation of NF-κB, MAPK and Akt. Additionally, Tat-Trx1 markedly reduced the production of inducible nitric oxide synthase, cyclooxygenase-2, IL-1β, IL-6 and TNF-α in macrophages. In a 12-O-tetradecanoylphorbol-13-acetate-induced mouse model, Tat-Trx1 reduced inflammatory damage by inhibiting inflammatory mediator and cytokine production. Collectively, these results demonstrated that Tat-Trx1 could exert anti-inflammatory effects by inhibiting the production of pro-inflammatory mediators and cytokines and by modulating MAPK signaling. Therefore, Tat-Trx1 may be a useful therapeutic agent for diseases induced by inflammatory damage.

The Protective Role of the Heme Catabolic Pathway in Hepatic Disorders

Significance: As the central metabolic organ, the liver is exposed to a variety of potentially cytotoxic, proinflammatory, profibrotic, and carcinogenic stimuli. To protect the organism from these deleterious effects, the liver has evolved a number of defense systems, which include antioxidant substrates and enzymes, anti-inflammatory tools, enzymatic biotransformation systems, and metabolic pathways. Recent Advances: One of the pivotal systems that evolved during phylogenesis was the heme catabolic pathway. Comprising the important enzymes heme oxygenase and biliverdin reductase, this complex pathway has a number of key functions including enzymatic activities, but also cell signaling, and DNA transcription. It further generates two important bile pigments, biliverdin and bilirubin, as well as the gaseous molecule carbon monoxide. These heme degradation products have potent antioxidant, immunosuppressive, and cytoprotective effects. Recent data suggest that the pathway participates in the regulation of metabolic and hormonal processes implicated in the pathogenesis of hepatic and other diseases. Critical Issues: This review discusses the impact of the heme catabolic pathway on major liver diseases, with particular focus on the involvement of cellular targeting and signaling in the pathogenesis of these conditions. Future Directions: To utilize the biological consequences of the heme catabolic pathway, several unique therapeutic strategies have been developed. Research indicates that pharmaceutical, nutraceutical, and lifestyle modifications positively affect the pathway, delivering potentially long-term clinical benefits. However, further well-designed studies are needed to confirm the clinical benefits of these approaches. Antioxid. Redox Signal. 35, 734-752.

Transduced Tat-PRAS40 prevents dopaminergic neuronal cell death through ROS inhibition and interaction with 14-3-3σ protein

Proline rich Akt substrate (PRAS40) is a component of mammalian target of rapamycin complex 1 (mTORC1) and activated mTORC1 plays important roles for cellular survival in response to oxidative stress. However, the roles of PRAS40 in dopaminergic neuronal cell death have not yet been examined. Here, we examined the roles of Tat-PRAS40 in MPP⁺- and MPTP-induced dopaminergic neuronal cell death. Our results showed that Tat-PRAS40 effectively transduced into SH-SY5Y cells and inhibited DNA damage, ROS generation, and apoptotic signaling in MPP⁺-induced SH-SY5Y cells. Further, these protective mechanisms of Tat-PRAS40 protein display through phosphorylation of Tat-PRAS40, Akt and direct interaction with 14-3-3σ protein, but not via the mTOR-dependent signaling pathway. In a Parkinson's disease animal model, Tat-PRAS40 transduced into dopaminergic neurons in mouse brain and significantly protected against dopaminergic cell death by phosphorylation of Tat-PRAS40, Akt and interaction with 14-3-3σ protein. In this study, we demonstrated for the first time that Tat-PRAS40 directly protects against dopaminergic neuronal cell death. These results indicate that Tat-PRAS40 may provide a useful therapeutic agent against oxidative stress-induced dopaminergic neuronal cell death, which causes diseases such as PD.

Anti-Inflammatory Effects of Weigela subsessilis Callus Extract via Suppression of MAPK and NF-κB Signaling

Weigela subsessilis is used in folk medicine to treat pain and allergic syndromes in Korea. However, the antibacterial and anti-inflammatory activities of W. subsessilis callus extract remain unexplored. In this study, we aimed to evaluate the W. subsessilis callus of pharmacological activity. Therefore, we first established in vitro calluses of W.subsessilis via plant tissue culture methods. We then evaluated the antioxidant and anti-inflammatory effects of W. subsessilis callus extract in lipopolysaccharide (LPS)-treated RAW264.7 macrophage cells. The W. subsessilis callus extract showed antioxidant and anti-inflammatory effects. These effects were regulated via suppression of mitogen-activated protein kinase signaling through LPS-induced translocation of nuclear factor kappa B (NF-κB) p65 from the cytoplasm to the nucleus. W. subsessilis callus extract also showed antibacterial and anti-inflammatory activities in Propionibacterium acnes-treated HaCaT keratinocyte cells. These results indicate that W. subsessilis callus extract has antioxidant, antibacterial and anti-inflammatory activities, suggesting its possible application in the treatment of inflammatory disorders.

Anti-inflammatory activity of the water extract of Chloranthus serratus roots in LPS-stimulated RAW264.7 cells mediated by the Nrf2/HO-1, MAPK and NF-κB signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Chloranthus serratus is a traditional Chinese medicine for treating arthritis and bruises.

AIM OF THE STUDY

To investigate the dose-effect relationship and molecular mechanisms of the water extract of C. serratus roots (WECR) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells.

MATERIALS AND METHODS

The cell viability was detected by CCK-8 method. One-step method, DCFH-DA fluorescence probe method and immunofluorescence method were used to detect nitric oxide (NO), reactive oxygen species (ROS) and p65 nuclear transcription, respectively. Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and prostaglandin E₂ (PGE₂) were detected by enzyme linked immunosorbent assay. Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA were detected by quantitative real-time PCR. Western blotting was taken to determine the contents of the relevant proteins in the nuclear transcription factor E2 related factor 2/heme oxygenase-1 (Nrf2/HO-1), mitogen-activated protein kinases (MAPK) and nuclear factor-kappa B (NF-κB) pathways.

RESULTS

The concentrations of 3, 30 and 300 μg/mL were optimized as low, medium and high concentrations of the WECR, respectively, and 1 μg/mL was selected as the optimal concentration of LPS to activate macrophages. The dose of the positive drug dexamethasone was 0.13 mg/mL. The WECR could not only inhibit LPS-induced cell differentiation and the overexpression of NO, IL-6, TNF-α, PGE₂ and ROS but also promote the expression of Nrf2 and HO-1, and down-regulate the phosphorylation levels of ERK, JNK, p38 and p65. After the WECR treatment, the expression levels of iNOS and COX-2 mRNA and nuclear translocation of p65 were all inhibited.

CONCLUSIONS

The WECR exerts its anti-inflammatory activity by inhibiting the MAPK and NF-κB pathways, activating the Nrf2/HO-1 pathway and down-regulating inflammatory factor levels in a dose-dependent manner.

Protective Role of Transduced Tat-Thioredoxin1 (Trx1) against Oxidative Stress-Induced Neuronal Cell Death via ASK1-MAPK Signal Pathway

Oxidative stress plays a crucial role in the development of neuronal disorders including brain ischemic injury. Thioredoxin 1 (Trx1), a 12 kDa oxidoreductase, has anti-oxidant and anti-apoptotic functions in various cells. It has been highly implicated in brain ischemic injury. However, the protective mechanism of Trx1 against hippocampal neuronal cell death is not identified yet. Using a cell permeable Tat-Trx1 protein, protective mechanism of Trx1 against hydrogen peroxide-induced cell death was examined using HT-22 cells and an ischemic animal model. Transduced Tat-Trx1 markedly inhibited intracellular ROS levels, DNA fragmentation, and cell death in H₂O₂-treatment HT-22 cells. Tat-Trx1 also significantly inhibited phosphorylation of ASK1 and MAPKs in signaling pathways of HT-22 cells. In addition, Tat-Trx1 regulated expression levels of Akt, NF-κB, and apoptosis related proteins. In an ischemia animal model, Tat-Trx1 markedly protected hippocampal neuronal cell death and reduced astrocytes and microglia activation. These findings indicate that transduced Tat-Trx1 might be a potential therapeutic agent for treating ischemic injury.

Tat-Biliverdin Reductase A Exerts a Protective Role in Oxidative Stress-Induced Hippocampal Neuronal Cell Damage by Regulating the Apoptosis and MAPK Signaling

Reactive oxygen species (ROS) is major risk factor in neuronal diseases including ischemia. Although biliverdin reductase A (BLVRA) plays a pivotal role in cell survival via its antioxidant function, its role in hippocampal neuronal (HT-22) cells and animal ischemic injury is not clearly understood yet. In this study, the effects of transducible fusion protein Tat-BLVRA on H₂O₂-induced HT-22 cell death and in an animal ischemia model were investigated. Transduced Tat-BLVRA markedly inhibited cell death, DNA fragmentation, and generation of ROS. Transduced Tat-BLVRA inhibited the apoptosis and mitogen activated protein kinase (MAPK) signaling pathway and it passed through the blood-brain barrier (BBB) and significantly prevented hippocampal cell death in an ischemic model. These results suggest that Tat-BLVRA provides a possibility as a therapeutic molecule for ischemia.

Biliverdin Reductase A (BVRA) Knockout in Adipocytes Induces Hypertrophy and Reduces Mitochondria in White Fat of Obese Mice

Biliverdin reductase (BVR) is an enzymatic and signaling protein that has multifaceted roles in physiological systems. Despite the wealth of knowledge about BVR, no data exist regarding its actions in adipocytes. Here, we generated an adipose-specific deletion of biliverdin reductase-A (BVRA) (Blvra^FatKO) in mice to determine the function of BVRA in adipocytes and how it may impact adipose tissue expansion. The Blvra^FatKO and littermate control (Blvra^Flox) mice were placed on a high-fat diet (HFD) for 12 weeks. Body weights were measured weekly and body composition, fasting blood glucose and insulin levels were quantitated at the end of the 12 weeks. The data showed that the percent body fat and body weights did not differ between the groups; however, Blvra^FatKO mice had significantly higher visceral fat as compared to the Blvra^Flox. The loss of adipocyte BVRA decreased the mitochondrial number in white adipose tissue (WAT), and increased inflammation and adipocyte size, but this was not observed in brown adipose tissue (BAT). There were genes significantly reduced in WAT that induce the browning effect such as Ppara and Adrb3, indicating that BVRA improves mitochondria function and beige-type white adipocytes. The Blvra^FatKO mice also had significantly higher fasting blood glucose levels and no changes in plasma insulin levels, which is indicative of decreased insulin signaling in WAT, as evidenced by reduced levels of phosphorylated AKT (pAKT) and Glut4 mRNA. These results demonstrate the essential role of BVRA in WAT in insulin signaling and adipocyte hypertrophy.

Transduced Tat-aldose Reductase Protects Hippocampal Neuronal Cells against Oxidative Stress-induced Damage

Aldose reductase (AR) protein, a member of the NADPH-dependent aldo-keto reductase family, reduces a wide range of aldehydes and enhances cell survival by inhibition of oxidative stress. Oxidative stress is known as one of the major pathological factor in ischemia. Since the precise function of AR protein in ischemic injury is fully unclear, we examined the function of AR protein in hippocampal neuronal (HT-22) cells and in an animal model of ischemia in this study. Cell permeable Tat-AR protein was produced by fusion of protein transduction domain in Tat for delivery into the cells. Tat-AR protein transduced into HT-22 cells and significantly inhibited cell death and regulated the mitogen-activate protein kinases (MAPKs), Bcl-2, Bax, and Caspase-3 under oxidative stress condition. In an ischemic animal model, Tat-AR protein transduced into the brain tissues through the blood-brain barrier (BBB) and drastically decreased neuronal cell death in hippocampal CA1 region. These results indicate that transduced Tat-AR protein has protective effects against oxidative stress-induced neuronal cell death in vitro and in vivo, suggesting that Tat-AR protein could be used as potential therapeutic agent in ischemic injury.

Heme Catabolic Pathway in Inflammation and Immune Disorders

In recent years, the heme catabolic pathway is considered to play an important regulatory role in cell protection, apoptosis, inflammation, and other physiological and pathological processes. An appropriate amount of heme forms the basic elements of various life activities, while when released in large quantities, it can induce toxicity by mediating oxidative stress and inflammation. Heme oxygenase (HO) -1 can catabolize free heme into carbon monoxide (CO), ferrous iron, and biliverdin (BV)/bilirubin (BR). The diverse functions of these metabolites in immune systems are fascinating. Decades work shows that administration of degradation products of heme such as CO and BV/BR exerts protective activities in systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS) and other immune disorders. This review elaborates the molecular and biochemical characterization of heme catabolic pathway, discusses the signal transduction and immunomodulatory mechanism in inflammation and summarizes the promising therapeutic strategies based on this pathway in inflammatory and immune disorders.

Cangrelor alleviates pulmonary fibrosis by inhibiting GPR17-mediated inflammation in mice

Pulmonary fibrosis is a progressive and intractable lung disease. Macrophages play a critical role in the progression of pulmonary fibrosis. Cangrelor, an anti-platelet agent, is also a non-selective Gprotein-coupled receptor 17 (GPR17) antagonist. GPR17 mediates microglial inflammation in the chronic phase of cerebral ischemia and regulates allergic pulmonary inflammation. In this study, we observed the effects of cangrelor on bleomycin (BLM)-induced macrophage cellular inflammation and BLM-induced pulmonary fibrosis in C57BL/6J mice. We found that BLM significantly increased GPR17 expression, the mRNA synthesis and release of inflammatory cytokines including TNF-α, IL-6 and TGF-β1 in murine RAW 264.7 macrophage cells. Knockdown of GPR17 attenuated the BLM-induced inflammatory responses. Cangrelor (2.5 μM-10 μM) significantly alleviated BLM-induced inflammatory response in RAW 264.7 macrophage cells in concentration-dependent manner. In BLM-induced fibrotic mouse lungs, GPR17 expression and GPR17-positive macrophages were increased. Cangrelor (2.5 mg/kg-10 mg/kg) alleviated pulmonary fibrosis in dose-dependent manner. Cangrelor not only reduced the number of GPR17-positive macrophages, but also decreased BLM-induced mRNA synthesis and release of inflammatory cytokine. As such, we concluded that cangrelor alleviates BLM-induced pulmonary fibrosis by suppressing GPR17-mediated inflammation. Cangrelor could be a potential therapeutic drug for pulmonary fibrosis.

PEP‑1‑glutaredoxin 1 protects against hippocampal neuronal cell damage from oxidative stress via regulation of MAPK and apoptotic signaling pathways

Oxidative stress is known to be a primary risk factor for neuronal diseases. Glutaredoxin (GLRX)‑1, a redox‑regulator of the thioredoxin superfamily, is known to exhibit an important role in cell survival via various cellular functions. However, the precise roles of GLRX1 in brain ischemia are still not fully understood. The present study investigated whether transduced PEP‑1‑GLRX1 protein has protective effects against oxidative stress in cells and in an animal model. Transduced PEP‑1‑GLRX1 protein increased HT‑22 cell viability under oxidative stress and this fusion protein significantly reduced intracellular reactive oxygen species and levels of DNA damage. In addition, PEP‑1‑GLRX1 protein regulated RAC‑a serine/threonine‑protein kinase and mitogen‑activated protein kinase signaling, in addition to apoptotic signaling including B cell lymphoma (Bcl)‑2, Bcl‑2 associated X, apoptosis regulator, pro‑caspase‑9 and p53 expression levels. In an ischemic animal model, it was verified that PEP‑1‑GLRX1 transduced into the Cornu Ammonis 1 region of the animal brain, where it markedly protected against ischemic injury. These results indicate that PEP‑1‑GLRX1 attenuates neuronal cell death resulting from oxidative stress in vitro and in vivo. Therefore, PEP‑1‑GLRX1 may exhibit a beneficial role in the treatment of neuronal disorders, including ischemic injury.

Biliverdin reductase and bilirubin in hepatic disease

The buildup of fat in the liver (hepatic steatosis) is the first step in a series of incidents that may drive hepatic disease. Obesity is the leading cause of nonalcoholic fatty liver disease (NAFLD), in which hepatic steatosis progresses to liver disease. Chronic alcohol exposure also induces fat accumulation in the liver and shares numerous similarities to obesity-induced NAFLD. Regardless of whether hepatic steatosis is due to obesity or long-term alcohol use, it still may lead to hepatic fibrosis, cirrhosis, or possibly hepatocellular carcinoma. The antioxidant bilirubin and the enzyme that generates it, biliverdin reductase A (BVRA), are components of the heme catabolic pathway that have been shown to reduce hepatic steatosis. This review discusses the roles for bilirubin and BVRA in the prevention of steatosis, their functions in the later stages of liver disease, and their potential therapeutic application.

Anti-inflammatory effects of ursodeoxycholic acid by lipopolysaccharide-stimulated inflammatory responses in RAW 264.7 macrophages

PURPOSE

The aim of this study was to investigate the anti-inflammatory effects of Ursodeoxycholic acid (UDCA) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages.

METHODS

We induced an inflammatory process in RAW 264.7 macrophages using LPS. The anti-inflammatory effects of UDCA on LPS-stimulated RAW 264.7 macrophages were analyzed using nitric oxide (NO). Pro-inflammatory and anti-inflammatory cytokines were analyzed by quantitative real time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). The phosphorylations of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 in mitogen-activated protein kinase (MAPK) signaling pathways and nuclear factor kappa-light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) signaling pathways were evaluated by western blot assays.

RESULTS

UDCA decreased the LPS-stimulated release of the inflammatory mediator NO. UDCA also decreased the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin 1-α (IL-1α), interleukin 1-β (IL-1β), and interleukin 6 (IL-6) in mRNA and protein levels. In addition, UDCA increased an anti-inflammatory cytokine interleukin 10 (IL-10) in the LPS-stimulated RAW 264.7 macrophages. UDCA inhibited the expression of inflammatory transcription factor nuclear factor kappa B (NF-κB) in LPS-stimulated RAW 264.7 macrophages. Furthermore, UDCA suppressed the phosphorylation of ERK, JNK, and p38 signals related to inflammatory pathways. In addition, the phosphorylation of IκBα, the inhibitor of NF-κB, also inhibited by UDCA.

CONCLUSION

UDCA inhibits the pro-inflammatory responses by LPS in RAW 264.7 macrophages. UDCA also suppresses the phosphorylation by LPS on ERK, JNK, and p38 in MAPKs and NF-κB pathway. These results suggest that UDCA can serve as a useful anti-inflammatory drug.

Tat-biliverdin reductase A protects INS-1 cells from human islet amyloid polypeptide-induced cytotoxicity by alleviating oxidative stress and ER stress

Human islet amyloid polypeptide (hIAPP), a major constituent of islet amyloid deposits, induces pancreatic β-cell apoptosis and eventually contributes to β-cell deficit in patients with type 2 diabetes mellitus (T2DM). In this study, Tat-mediated transduction of biliverdin reductase A (BLVRA) was investigated in INS-1 cells to examine whether exogenous supplementation of BLVRA prevented hIAPP-induced apoptosis and dysfunction in insulin secretion in β-cells. Tat-BLVRA fusion protein was efficiently delivered into INS-1 cells in a time- and dose-dependent manner. Exposure of cells to hIAPP induced apoptotic cell death, which was dose-dependently inhibited by pre-treatment with Tat-BLVRA for 1 h. Transduced Tat-BLVRA reduced hIAPP-evoked generation of reactive oxygen species, a crucial mediator of β-cell destruction. Immunoblot analysis showed that Tat-BLVRA suppressed hIAPP-induced increase in the levels of proteins involved in endoplasmic reticulum (ER) stress and apoptosis signaling. Transduced Tat-BLVRA also recovered hIAPP-induced dysfunction in basal and glucose-stimulated insulin secretions. These results suggested that transduced Tat-BLVRA enhanced the tolerance of β-cells against IAPP-induced cytotoxicity by alleviating oxidative stress and ER stress. Therefore, Tat-mediated transduction of BLVRA may provide a potential tool to ameliorate β-cell deficit in pancreas with T2DM.

Dihydromyricetin suppresses inflammatory responses in vitro and in vivo through inhibition of IKKβ activity in macrophages

Dihydromyricetin (DMY) a flavonoid derived from medicinal plant Ampelopsis grossedentata, possesses anti-oxidative and anti-inflammatory effects in vitro, however, the in vivo anti-inflammatory action of DMY remains unknown. In the current study, carrageenan-induced paw edema in rat, an acute inflammation model, and RAW264.7 macrophages activated by LPS were employed to evaluate the anti-inflammatory potency of DMY in vivo and in vitro. Results showed that DMY significantly attenuated rat paw edema induced by carrageenan. Also, DMY markedly inhibited NO secretion, iNOS, and COX-2 protein expression, as well as p65 phosphorylation via suppression of IKKβ activity and IKKα/β phosphorylation in RAW264.7 cells. And using high resolution Atomic Force Microscope (AFM), we also proved that DMY prevented morphological change and membrane alterations of RAW 264.7 macrophages caused by LPS stimulation. As activation of macrophages is one of major factors in carrageenan-induced paw edema of rats, the anti-inflammatory action of DMY is suggested to be closely associated with suppression of macrophage activation. These findings indicate that DMY is valuable of being further investigated as a candidate new agent for treating inflammatory conditions, and suggest that AFM could be a powerful nanotool for anti-inflammatory investigations. SCANNING 38:901-912, 2016. © 2016 Wiley Periodicals, Inc.

Tat-PRAS40 prevent hippocampal HT-22 cell death and oxidative stress induced animal brain ischemic insults

Proline rich Akt substrate (PRAS40) is a component of mammalian target of rapamycin complex 1 (mTORC1) and is known to play an important role against reactive oxygen species-induced cell death. However, the precise function of PRAS40 in ischemia remains unclear. Thus, we investigated whether Tat-PRAS40, a cell-permeable fusion protein, has a protective function against oxidative stress-induced hippocampal neuronal (HT-22) cell death in an animal model of ischemia. We showed that Tat-PRAS40 transduced into HT-22 cells, and significantly protected against cell death by reducing the levels of H2O2 and derived reactive species, and DNA fragmentation as well as via the regulation of Bcl-2, Bax, and caspase 3 expression levels in H2O2 treated cells. Also, we showed that transduced Tat-PARS40 protein markedly increased phosphorylated RRAS40 expression levels and 14-3-3σ complex via the Akt signaling pathway. In an animal ischemia model, Tat-PRAS40 effectively transduced into the hippocampus in animal brain and significantly protected against neuronal cell death in the CA1 region. We showed that Tat-PRAS40 protein effectively transduced into hippocampal neuronal cells and markedly protected against neuronal cell damage. Therefore, we suggest that Tat-PRAS40 protein may be used as a therapeutic protein for ischemia and oxidative stress-induced brain disorders.

The Anti-Inflammatory Effects and Mechanisms of Eupafolin in Lipopolysaccharide-Induced Inflammatory Responses in RAW264.7 Macrophages

Eupafolin is a flavone isolated from Artemisia princeps Pampanini (family Asteraceae). The aim of this study was to examine the anti-inflammatory effects of eupafolin in lipopolysaccharide (LPS)-treated RAW264.7 macrophages and LPS-induced mouse skin and lung inflammation models and to identify the mechanism underlying these effects. Eupafolin decreased the LPS-induced release of inflammatory mediators (iNOS, COX-2 and NO) and proinflammatory cytokines (IL-6 and TNF-α) from the RAW264.7 macrophages. Eupafolin inhibited the LPS-induced phosphorylation of p38 MAPK, ERK1/2, JNK, AKT and p65 and the nuclear translocation of p65 and c-fos. These effects were mainly mediated by the inhibition of JNK. In the mouse paw and lung models, eupafolin effectively suppressed the LPS-induced edema formation and down-regulated iNOS and COX-2 expression. These results demonstrated that eupafolin exhibits anti-inflammatory properties and suggested that eupafolin can be developed as an anti-inflammatory agent.

Anti-inflammatory activity of ethanolic extract from skipjack tuna (Katsuwonus pelamis) heart in LPS-induced RAW 264.7 cells and mouse ear edema model

This study investigated the anti-inflammatory activity of the ethanolic extract (THEE) obtained from the heart of skipjack tuna using lipopolysaccharide (LPS)-induced RAW 264.7 cells. THEE markedly suppressed the production of nitric oxide (NO), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and IL-1β in a dose-dependent manner. In addition, THEE decreased the expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor-kappa B p65 (NF-κB p65), and mitogen-activated protein kinases (MAPKs) including phosphorylated c-Jun NH₂-terminal kinase (p-JNK), phosphorylated extracellular signal-related kinase (p-ERK), and p-p38 proteins. Moreover, THEE orally treated at doses of 50, 100, and 250 mg/kg inhibited the croton oil-induced edema formation and the reduction of the epidermal/dermal thickness and the mast cell numbers was observed in histological analysis. There were no mortalities occurred in mice administered THEE at 5,000 mg/kg body weight. Taken together, these results indicate that THEE exerts the anti-inflammatory activities via inhibition of NF-κB and MAPKs activation.

Tat-ATOX1 inhibits streptozotocin-induced cell death in pancreatic RINm5F cells and attenuates diabetes in a mouse model

Antioxidant 1 (ATOX1) functions as an antioxidant against hydrogen peroxide and superoxide, and therefore may play a significant role in many human diseases, including diabetes mellitus (DM). In the present study, we examined the protective effects of Tat-ATOX1 protein on streptozotocin (STZ)-exposed pancreatic insulinoma cells (RINm5F) and in a mouse model of STZ-induced diabetes using western blot analysis, immunofluorescence staining and MTT assay, as well as histological and biochemical analysis. Purified Tat-ATOX1 protein was efficiently transduced into RINm5F cells in a dose- and time-dependent manner. Additionally, Tat-ATOX1 protein markedly inhibited reactive oxygen species (ROS) production, DNA damage and the activation of Akt and mitogen activated protein kinases (MAPKs) in STZ-exposed RINm5F cells. In addition, Tat-ATOX1 protein transduced into mice pancreatic tissues and significantly decreased blood glucose and hemoglobin A1c (HbA1c) levels as well as the body weight changes in a model of STZ-induced diabetes. These results indicate that transduced Tat-ATOX1 protein protects pancreatic β-cells by inhibiting STZ-induced cellular toxicity in vitro and in vivo. Based on these findings, we suggest that Tat-ATOX1 protein has potential applications as a therapeutic agent for oxidative stress-induced diseases including DM.

Tat-NOL3 protects against hippocampal neuronal cell death induced by oxidative stress through the regulation of apoptotic pathways

Oxidative stress-induced apoptosis is associated with neuronal cell death and ischemia. The NOL3 [nucleolar protein 3 (apoptosis repressor with CARD domain)] protein protects against oxidative stress-induced cell death. However, the protective mechanism responsible for this effect as well as the effects of NOL3 against oxidative stress in ischemia remain unclear. Thus, we examined the protective effects of NOL3 protein on hydrogen peroxide (H2O2)-induced oxidative stress and the mechanism responsible for these effects in hippocampal neuronal HT22 cells and in an animal model of forebrain ischemia using Tat-fused NOL3 protein (Tat-NOL3). Purified Tat-NOL3 protein transduced into the H2O2-exposed HT22 cells and inhibited the production of reactive oxygen species (ROS), DNA fragmentation and reduced mitochondrial membrane potential (ΔΨm). In addition, Tat-NOL3 prevented neuronal cell death through the regulation of apoptotic signaling pathways including Bax, Bcl-2, caspase-2, -3 and -8, PARP and p53. In addition, Tat-NOL3 protein transduced into the animal brains and significantly protected against neuronal cell death in the CA1 region of the hippocampus by regulating the activation of microglia and astrocytes. Taken together, these findings demonstrate that Tat-NOL3 protein protects against oxidative stress-induced neuronal cell death by regulating oxidative stress and by acting as an anti-apoptotic protein. Thus, we suggest that Tat-NOL3 represents a potential therapeutic agent for protection against ischemic brain injury.

Biliverdin Reductase A (BVRA) Mediates Macrophage Expression of Interleukin-10 in Injured Kidney

Biliverdin reductase A is an enzyme, with serine/threonine/tyrosine kinase activation, converting biliverdin (BV) to bilirubin (BR) in heme degradation pathway. It has been reported to have anti-inflammatory and antioxidant effect in monocytes and human glioblastoma. However, the function of BVRA in polarized macrophage was unknown. This study aimed to investigate the effect of BVRA on macrophage activation and polarization in injured renal microenvironment. Classically activated macrophages (M1macrophages) and alternative activation of macrophages (M2 macrophages) polarization of murine bone marrow derived macrophage was induced by GM-CSF and M-CSF. M1 polarization was associated with a significant down-regulation of BVRA and Interleukin-10 (IL-10), and increased secretion of TNF-α. We also found IL-10 expression was increased in BVRA over-expressed macrophages, while it decreased in BVRA knockdown macrophages. In contrast, BVRA over-expressed or knockdown macrophages had no effect on TNF-α expression level, indicating BVRA mediated IL-10 expression in macrophages. Furthermore, we observed in macrophages infected with recombinant adenoviruses BVRA gene, which BVRA over-expressed enhanced both INOS and ARG-1 mRNA expression, resulting in a specific macrophage phenotype. Through in vivo study, we found BVRA positive macrophages largely existed in mice renal ischemia perfusion injury. With the treatment of the regular cytokines GM-CSF, M-CSF or LPS, excreted in the injured renal microenvironment, IL-10 secretion was significantly increased in BVRA over-expressed macrophages. In conclusion, the BVRA positive macrophage is a source of anti-inflammatory cytokine IL-10 in injured kidney, which may provide a potential target for treatment of kidney disease.