A novel peptide derived from human pancreatitis-associated protein inhibits inflammation in vivo and in vitro and blocks NF-kappa B signaling pathway

A novel peptide derived from the mannose binding lectin inhibits LPS-activated TLR4/NF-κB signaling and suppresses ocular inflammation

Uveitis is a major cause of vision impairment worldwide. Current treatments have limited effectiveness but severe complications. Mannose binding lectin (MBL) is an important protein of the innate immune system that binds to TLR4 and suppresses LPS-induced inflammatory cytokine secretion. MBL-mediated inhibition of inflammation via the TLR4 pathway and MBL-derived peptides might be a potential therapeutics. In this study, we designed a novel MBL-derived peptide, WP-17, targeting TLR4. Bioinformatics analysis was conducted for the sequence, structure and biological properties of WP-17. The binding of WP-17 to THP-1 cells was analyzed using flow cytometry. Signaling molecules were analyzed by western blotting, and activation of NF-κB was measured by immunofluorescence-histochemical analysis. Effects of WP-17 were studied in vitro using LPS-stimulated THP-1 cells and in vivo in endotoxin-induced uveitis (EIU). Our results showed that WP-17 could bind to TLR4 expressed on macrophages, thus downregulating the expression levels of MyD88, IRAK-4, and TRAF-6, and inhibiting the downstream NF-kB signaling pathway and LPS-induced expression of TNF-α and IL-6 in THP-1 cells. Moreover, in EIU rats, intravitreal pretreatment with WP-17 demonstrated significant inhibitory effects on ocular inflammation, attenuating the clinical and histopathological manifestations of uveitis, reducing protein leakage and cell infiltration into the aqueous humor, and suppressing TNF-α and IL-6 production in ocular tissues. In summary, our study provides the first evidence of a novel MBL-derived peptide that suppressed activation of the NF-кB pathway by targeting TLR4. The peptide effectively inhibited rat uveitis and may be a promising candidate for the management of ocular inflammatory diseases.

5-ALA/SFC Ameliorates Endotoxin-Induced Ocular Inflammation in Rats by Inhibiting the NF-κB Signaling Pathway and Activating the HO-1/Nrf2 Signaling Pathway

Sodium ferrous citrate (SFC) is involved in the metabolism of 5-aminolevulinic acid (5-ALA) and enhances its anti-inflammatory effects. The effects of 5-ALA/SFC on inflammation in rats with endotoxin-induced uveitis (EIU) have yet to be elucidated. In this study, during lipopolysaccharide injection, 5-ALA/SFC (10 mg/kg 5-ALA plus 15.7 mg/kg SFC) or 5-ALA (10 or 100 mg/kg) was administered via gastric gavage, wherein we saw that 5-ALA/SFC ameliorated ocular inflammation in EIU rats by suppressing clinical scores; by infiltrating cell counts, aqueous humor protein, and inflammatory cytokine levels; and by improving histopathological scores to the same extent as 100 mg/kg 5-ALA. Immunohistochemistry showed that 5-ALA/SFC suppressed iNOS and COX-2 expression, NF-κB activation, IκB-α degradation, and p-IKKα/β expression, and activated HO-1 and Nrf2 expression. Therefore, this study has investigated how 5-ALA/SFC reduces inflammation and revealed the pathways involved in EIU rats. 5-ALA/SFC is shown to inhibit ocular inflammation in EIU rats by inhibiting NF-κB and activating the HO-1/Nrf2 pathways.

Role of regenerating islet-derived proteins in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an inflammatory disorder of the gastrointestinal tract that affects millions of patients worldwide. It has a complex and multifactorial etiology leading to excessive exposure of intestinal epithelium to microbial antigens, inappropriate activation of the immune system and ultimately to the damage of intestinal tissues. Although numerous efforts have been made to improve the disease management, IBD remains persistently recurring and beyond cure. This is due largely to the gaps in our understanding of the pathogenesis of IBD that hamper the development of timely diagnoses and effective treatment. However, some recent discoveries, including the beneficial effects of interleukin-22 (IL-22) on the inflamed intestine, have shed light on a self-protective mechanism in IBD. Regenerating islet-derived (REG/Reg) proteins are small secretory proteins which function as IL-22's downstream effectors. Mounting studies have demonstrated that IBD patients have significantly increased REG expressions in the injured intestine, but with undefined mechanisms and roles. The reported functions of REG/Reg proteins in intestinal homeostasis, such as those of antibacterial, anti-inflammatory and tissue repair, lead us to discuss their potential mechanisms and clinical relevance in IBD in order to advance IBD research and management.

A HGF‑derived peptide suppresses EMT in human lens epithelial cells via the TGF‑β/Smad and Akt/mTOR signaling pathways

Posterior capsule opacification (PCO) as a result of proliferation and fibrogenesis of lens epithelial cells (LECs) is the most frequent long‑term complication of modern cataract surgery. LECs may undergo epithelial‑mesenchymal transition (EMT) that resembles the morphological and molecular characteristics of PCO. A pre‑identified novel, hepatocyte growth factor (HGF)‑derived peptide H‑RN, was reported to exhibit anti‑angiogenic activity and anti‑inflammatory effects in ocular cells both in vitro and in vivo. However, the role of H‑RN in the promotion of the development of EMT in LECs is unknown. In the present study, the effects of H‑RN on the development of EMT induced by transforming growth factor (TGF)‑β in human LECs, and the possible signaling pathways participating in this process were investigated. The results showed that H‑RN promoted the expression of the EMT‑associated markers, α‑smooth muscle actin and fibronectin, whereas the expression of E‑cadherin and connexin 43 were reduced. The morphological changes typically associated with EMT seen in LECs induced by TGF‑β2 were inhibited by H‑RN, which was consistent with the effects of a TGF‑β2 inhibitor, SB431542. Smad2 and Smad3 phosphorylation induced by TGF‑β2 were reduced by H‑RN, and phosphorylation of Akt, mTOR and P70S6K induced by TGF‑β2 were also notably reduced by H‑RN in LECs. Therefore, the results of the present study showed that H‑RN treatment significantly suppressed the development of EMT induced by TGF‑β2, at least partially through the TGF‑β/Smad and Akt/mTOR signaling pathways in human LECs. The present study highlights that H‑RN, a novel HGF‑derived peptide, may be a novel therapeutic agent for prevention and treatment of PCO.

Oral delivery of pancreatitis-associated protein by Lactococcus lactis displays protective effects in dinitro-benzenesulfonic-acid-induced colitis model and is able to modulate the composition of the microbiota

Antimicrobial peptides secreted by intestinal immune and epithelial cells are important effectors of innate immunity. They play an essential role in the maintenance of intestinal homeostasis by limiting microbial epithelium interactions and preventing unnecessary microbe‐driven inflammation. Pancreatitis‐associated protein (PAP) belongs to Regenerating islet‐derived III proteins family and is a C‐type (Ca⁺² dependent) lectin. PAP protein plays a protective effect presenting anti‐inflammatory properties able to reduce the severity of colitis, preserving gut barrier and epithelial inflammation. Here, we sought to determine whether PAP delivered at intestinal lumen by recombinant Lactococcus lactis strain (LL‐PAP) before and after chemically induced colitis is able to reduce the severity in two models of colitis. After construction and characterization of our recombinant strains, we tested their effects in dinitro‐benzenesulfonic‐acid (DNBS) and Dextran sulfate sodium (DSS) colitis model. After the DNBS challenge, mice treated with LL‐PAP presented less severe colitis compared with PBS and LL‐empty‐treated mice groups. After the DSS challenge, no protective effects of LL‐PAP could be detected. We determined that after 5 days administration, LL‐PAP increase butyrate producer's bacteria, especially Eubacterium plexicaudatum. Based on our findings, we hypothesize that a treatment with LL‐PAP shifts the microbiota preventing the severity of colon inflammation in DNBS colitis model. These protective roles of LL‐PAP in DNBS colitis model might be through intestinal microbiota modulation.

PAPep Inhibits Secretion of Poly(I:C)-Induced Inflammatory Cytokines and ICAM-1 Expression in Corneal Fibroblasts by Suppressing the NF-κB/p38 Pathway

PURPOSE

To assess the anti-inflammatory effect and mechanism of a novel peptide, PAPep, in poly(I:C)-stimulated corneal fibroblasts.

METHODS

Corneal fibroblasts were treated with poly(I:C) to elicit inflammation. Real-time polymerase chain reaction (PCR) and ELISA were used to measure the mRNA and protein levels of interleukin (IL)-6, monocyte chemotactic factor (MCP)-1, and interferon gamma (IFN-γ). Real-time PCR, immunofluorescence, and immunoblot were performed to determine ICAM-1 expression. Translocation of NF-κB p65 was observed by immunofluorescence. Phosphorylation of IκBα, NF-κB, and mitogen-activated protein kinase (MAPK) (p38, JNK and ERK) were detected by western blot.

RESULTS

The results showed that PAPep effectively decreased mRNA and protein expression of IL-6, MCP-1, and IFN-γ in corneal fibroblasts exposed to poly(I:C). In addition, PAPep reduced mRNA and protein levels of ICAM-1. The NF-κB and MAPK(p38) pathway were inhibited by PAPep treatment, as indicated by suppression of p65 nuclear translocation, and IκBα, NF-κB, and p38 activation. PAPep showed no effect on JNK or ERK activity.

CONCLUSIONS

PAPep attenuates the expression of inflammatory cytokines and ICAM-1 in corneal fibroblasts induced by poly(I:C) through blocking the NF-κB and MAPK(p38) pathway. PAPep may be considered a promising therapeutic agent for treating viral keratitis.

Angiotensin-converting enzyme 2-angiotensin (1-7)-Mas axis prevents pancreatic acinar cell inflammatory response via inhibition of the p38 mitogen-activated protein kinase/nuclear factor-κB pathway

The aim of the present study was to investigate the role of the angiotensin-converting enzyme (ACE)2-angiotensin‑(Ang)-(1-7)-Mas axis in the pathogenesis of pancreatitis and the association between this axis and the p38 mitogen-activated protein kinase (p38 MAPK)/nuclear factor (NF-κB) signaling pathway in pancreatic acinar cells. Mouse pancreatic acinar cancer (MPC-83) cells were stimulated with 10 nM caerulein (CAE) to create an in vitro model of acute pancreatitis, and collected for analysis at 2, 6, 12, 24 and 48 h post stimulation. In addition, cells were pretreated with different concentrations of Ang‑(1‑7), Ang‑(1‑7) antagonist A779, p38 MAPK inhibitor SB203580 or ACE2 inhibitor DX600 for 30 min, and then stimulated with CAE for 24 h. The ACE2, Mas receptor, p38 MAPK, phosphorylated (p)-p38 MAPK and NF-κB expression levels were evaluated using western blotting and immunofluorescence. p38 MAPK, NF-κB, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-8 and IL-10 mRNA expression levels were assessed using reverse transcription-quantitative polymerase chain reaction. The results of the immunofluorescence assay demonstrated that ACE2 and p38 MAPK were present mainly in the cytoplasm, while the Mas receptor was located mainly in the cell membrane. ACE2, p38 MAPK and p-p38 MAPK protein levels were significantly increased (P<0.05) following stimulation with CAE compared with those in the control group and peaked at 24 h. Mas receptor protein levels were significantly upregulated (P<0.05) between 6 and 24 h, peaking at 12 h. Ang‑(1‑7) and SB203580 downregulated p-p38 MAPK and NF-κB expression and the mRNA levels of inflammatory factors IL-6, TNF-α and IL-8, but upregulated the mRNA level of inflammatory factor IL-10 compared with those treated with CAE alone. These results were supported by the opposite outcomes observed for cells treated with A779 or DX600. Therefore, it was concluded that the ACE2-Ang‑(1‑7)-Mas axis significantly inhibits pancreatitis by inhibition of the p38 MAPK/NF-κB signaling pathway.

Characterization and production of multifunctional cationic peptides derived from rice proteins

Food proteins have been identified as a source of bioactive peptides. These peptides are inactive within the sequence of the parent protein and must be released during gastrointestinal digestion, fermentation, or food processing. Of bioactive peptides, multifunctional cationic peptides are more useful than other peptides that have specific activity in promotion of health and/or the treatment of diseases. We have identified and characterized cationic peptides from rice enzymes and proteins that possess multiple functions, including antimicrobial, endotoxin-neutralizing, arginine gingipain-inhibitory, and/or angiogenic activities. In particular, we have elucidated the contribution of cationic amino acids (arginine and lysine) in the peptides to their bioactivities. Further, we have discussed the critical parameters, particularly proteinase preparations and fractionation or purification, in the enzymatic hydrolysis process for producing bioactive peptides from food proteins. Using an ampholyte-free isoelectric focusing (autofocusing) technique as a tool for fractionation, we successfully prepared fractions containing cationic peptides with multiple functions.

Inhibitory effect of a novel peptide, H-RN, on keratitis induced by LPS or poly(I:C) in vitro and in vivo via suppressing NF-κB and MAPK activation

Background

Keratitis is a common cause of blindness. Current anti-inflammatory drugs used in keratitis have profound side effects. Small peptides derived from endogenous proteins potentially display both desired efficiency and safety. We identified an 11-amino-acid peptide, H-RN, from hepatocyte growth factor (HGF), an endogenous protein with anti-inflammatory properties. We evaluated the effects of H-RN in keratitis in vitro and in vivo.

Methods

In vitro, corneal fibroblasts were stimulated with LPS or poly(I:C), surrogates for bacteria and viruses. Inflammatory cytokines, intercellular cell adhesion molecule-1 (ICAM-1), translocation of NF-κB p65, activation of IκBα, NF-κB, and MAPKs were detected. In vivo, keratitis in rats was induced by LPS. Clinical, histological observation, and quantification of cytokines in the cornea were conducted. H-RN safety was measured by cell viability, clinical, histological, and microstructural observations.

Results

H-RN inhibited IL-6, monocyte chemotactic protein-1(MCP-1), Interferon- γ(IFN-γ), and ICAM-1 expression triggered by LPS or poly(I:C), alleviated the clinical manifestation and reduced the clinical score in keratitis in vivo. The histological disorder and proinflammatory cytokines of the cornea were also reduced. The translocation of NF-κB and phosphorylation of IκBα, NF-κB, p38, JNK, and ERK were significantly inhibited by H-RN. No sign of toxicity was observed.

Conclusions

H-RN effectively attenuated keratitis in vivo and in vitro induced by LPS or poly(I:C) through blocking NF-κB and MAPK signaling pathways. It may be a promising and safe agent in treating keratitis.

Luteolin protects mice from severe acute pancreatitis by exerting HO-1-mediated anti-inflammatory and antioxidant effects

Reseda odorata L. has long been used in traditional Asian medicine for the treatment of diseases associated with oxidative injury and acute inflammation, such as endotoxemia, acute lung injury, acute myocardial infarction and hepatitis. Luteolin, the main component of Reseda odorata L., which is also widely found in many natural herbs and vege-tables, has been shown to induce heme oxygenase-1 (HO-1) expression to exert anti-inflammatory and antioxidant effects. In this study, we aimed to examine the effects of luteolin on mice with severe acute pancreatitis (SAP), and to explore the underlying mechanisms. Cerulein and lipopolysaccharide were used to induce SAP in male Institute of Cancer Research (ICR) mice in the SAP group. The SAP group was divided into 4 subgroups, as follows: the vehicle, luteolin, zinc protoporphyrin (ZnPP) only, and luteolin (Lut) + ZnPP (luteolin plus zinc protoporphyrin treatment) groups. The wet/dry weight ratios, hematoxylin and eosin staining and pathological scores of pancreatic tissues were assessed and compared to those of the control mice. Amylase, lipase, nuclear factor-κB (NF-κB) and myeloperoxidase activities, and malondialdehyde, tumor necrosis factor α (TNFα), interleukin (IL)-6, IL-10 and HO-1 levels, as well as the expression of HO-1 were determined in serum and/or pancreatic tissue samples. SAP was successfully induced in male mice compared to normal control mice. The wet/dry weight ratios, pathological scores, and amylase and lipase activity, as well as the levels of TNFα and IL-6 were significantly reduced in the pancreatic tissues of the mice in the Lut group compared with those of the mice in the vehicle group. The Lut group exhibited a significant increase in HO-1 expression in the pancreas and enhanced serum HO-1 and IL-10 levels compared with the vehicle group. The suppression of HO-1 activity in the ZnPP group significantly abolished the protective effects of luteolin. NF-κB expression in the pancreatic tissues from the mice in the Lut + ZnPP group was significantly increased following the suppression of HO-1 activity. On the whole, our findings demonstrate that luteolin protects mice from SAP by inducing HO-1-mediated anti-inflammatory and antioxidant activities, in association with the suppression of the activation of the NF-κB pathway.

Preventive effect of chrysin on experimental autoimmune uveitis triggered by injection of human IRBP peptide 1-20 in mice

Uveitis is a common cause of blindness worldwide. Experimental autoimmune uveitis (EAU) is an animal model of noninfectious uveitis. Chrysin (5,7-dihydroxyflavone) is a member of the flavonoid family and has anti-inflammatory effects. We immunized C57BL/6J mice with human interphotoreceptor retinoid-binding protein peptide 1-20 to induce EAU. Chrysin was administered intragastrically at 25 mg/kg daily to the chrysin-treated mice from 3 days before immunization to 21 days after immunization. Vehicle was administered to the mice in the control group according to the same protocol. Lower clinical and histopathological scores, increased integrity of the blood-retinal barrier (BRB) and higher expression of tight junction proteins were observed in the chrysin-treated mice. Chrysin significantly decreased the proportions of Th1, Th17 and CD4⁺CD3⁺CD62L⁺ Th0 cells, and increased the proportion of Treg cells. Both macrophage infiltration and the expression of inducible nitric oxide synthase in the retina were efficiently inhibited by chrysin treatment. In chrysin-treated mice, the expression of interferon-γ, interleukin (IL)-17A, IL-6, IL-1β and tumor necrosis factor-α was reduced in the retina, whereas higher levels of transforming growth factor-β were detected. Furthermore, NF-κBp65 was downregulated after chrysin treatment. In conclusion, as an anti-inflammatory molecule, chrysin exerts a preventive effect on EAU by modulating the balance among helper T-cell subsets and suppressing ocular inflammation, thereby maintaining the integrity of the BRB.

Endotoxin-neutralizing activity and mechanism of action of a cationic α-helical antimicrobial octadecapeptide derived from α-amylase of rice

We have previously reported that AmyI-1-18, an octadecapeptide derived from α-amylase (AmyI-1) of rice, is a novel cationic α-helical peptide that exhibited antimicrobial activity against human pathogens, including Porphyromonas gingivalis, Pseudomonas aeruginosa, Propionibacterium acnes, Streptococcus mutans, and Candida albicans. In this study, to further investigate the potential functions of AmyI-1-18, we examined its inhibitory ability against the endotoxic activities of lipopolysaccharides (LPSs, smooth and Rc types) and lipid A from Escherichia coli. AmyI-1-18 inhibited the production of endotoxin-induced nitric oxide (NO), an inflammatory mediator, in mouse macrophages (RAW264) in a concentration-dependent manner. The results of a chromogenic Limulus amebocyte lysate assay illustrated that the ability [50% effective concentration (EC50): 0.17 μM] of AmyI-1-18 to neutralize lipid A was similar to its ability (EC50: 0.26 μM) to neutralize LPS, suggesting that AmyI-1-18 specifically binds to the lipid A moiety of LPS. Surface plasmon resonance analysis of the interaction between AmyI-1-18 and LPS or lipid A also suggested that AmyI-1-18 directly binds to the lipid A moiety of LPS because the dissociation constant (KD) of AmyI-1-18 with lipid A is 5.6×10(-10) M, which is similar to that (4.3×10(-10) M) of AmyI-1-18 with LPS. In addition, AmyI-1-18 could block the binding of LPS-binding protein to LPS, although its ability was less than that of polymyxin B. These results suggest that AmyI-1-18 expressing antimicrobial and endotoxin-neutralizing activities is useful as a safe and potent host defense peptide against pathogenic Gram-negative bacteria in many fields of healthcare.

Regenerating gene (REG) product and its potential clinical usage

INTRODUCTION

The regenerating gene (Reg) was identified in regenerating islets and its related genes were revealed to constitute the Reg gene family. Reg family proteins act as growth factors for several cells. Recently, autoimmunity against the Reg family proteins has been reported in several diseases. In addition, the Reg family genes were found to be expressed in a large number of cancers and to influence prognosis.

AREAS COVERED

The historical background and current view of the structure, function, and expression of Reg family genes/proteins and their physiological/pathological significance in several diseases are described. Based on the findings, the diagnostic/therapeutic potential of Reg family genes/proteins is also discussed.

EXPERT OPINION

Autoimmunity against Reg family proteins may be a new diagnostic marker and/or therapeutic target for immune-mediated diseases. Treatment aimed at the expansion of the β-cell mass by the Reg genes/proteins, combined with the abrogation of autoimmunity, constitutes a potential approach for the treatment of diabetes. Conversely, some cancer cells have gained the ability to overexpress the Reg genes/proteins, thereby enhancing their proliferative capacities, resulting in these cells having a considerable growth advantage. Thus, the Reg genes/proteins are expected to be a new prognostic marker in cancer and/or a future therapeutic target.

HIP/PAP prevents excitotoxic neuronal death and promotes plasticity

Objectives

Excitotoxicity plays a significant role in the pathogenesis of perinatal brain injuries. Among the consequences of excessive activation of the N-methyl-d-aspartate (NMDA)-type glutamate are oxidative stress caused by free radical release from damaged mitochondria, neuronal death and subsequent loss of connectivity. Drugs that could protect nervous tissue and support regeneration are attractive therapeutic options. The hepatocarcinoma intestine pancreas protein/pancreatitis-associated protein I (HIP/PAP) or Reg3α, which is approved for clinical testing for the protection and regeneration of the liver, is upregulated in the central nervous system following injury or disease. Here, we examined the neuroprotective/neuroregenerative potential of HIP/PAP following excitotoxic brain injury.

Methods

We studied the expression of HIP/PAP and two of its putative effectors, cAMP-regulated phosphoprotein 19 (ARPP19) and growth-associated protein 43 (GAP-43), in the neonatal brain, and the protective/regenerative properties of HIP/PAP in three paradigms of perinatal excitotoxicity: intracerebral injection of the NMDA agonist ibotenate in newborn pups, a pediatric model of traumatic brain injury, and cultured primary cortical neurons.

Results

HIP/PAP, ARPP19, and GAP-43 were expressed in the neonatal mouse brain. HIP/PAP prevented the formation of cortical and white matter lesions and reduced neuronal death and glial activation following excitotoxic insults in vivo. In vitro, HIP/PAP promoted neuronal survival, preserved neurite complexity and fasciculation, and protected cell contents from reactive oxygen species (ROS)-induced damage.

Interpretation

HIP/PAP has strong neuroprotective/neuroregenerative potential following excitotoxic injury to the developing brain, and could represent an interesting therapeutic strategy in perinatal brain injury.

Green tea extract treatment alleviates ocular inflammation in a rat model of endotoxin-induced uveitis

Green tea extract (GTE) ingested by rats exerted anti-oxidative activities in various ocular tissues as shown in our previous studies. The present work investigated anti-inflammatory effects of GTE on endotoxin-induced uveitis (EIU). EIU was generated in adult rats by a footpad injection of 1 mg/kg lipopolysaccharide (LPS). Oral administration of GTE (550 mg/kg) was given one, two or four times after LPS injection. Twenty-four hours later, LPS produced severe hyperemia and edema in the iris. Immunocytochemical examinations showed an accumulation of infiltrating cells in the aqueous humor that were immunopositive for cluster of differentiation 43 (CD43) and CD68, markers for leucocytes and macrophages, respectively. Analyses of the aqueous humor showed an increase in pro-inflammatory mediators including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1). GTE treatments improved the clinical manifestations and reduced infiltrating cells and protein exudation in the aqueous humor, which were not observed under half dose of GTE (275 mg/kg). The number of CD68 positive macrophages residing in the iris and ciliary was also reduced. GTE suppressed production of TNF-α, IL-6 and MCP-1 in the aqueous humor, which was associated with a down-regulation of LPS receptor complex subunits, Toll-like receptor 4 (TLR-4) and CD14, and suppression of nuclear factor-kappa Bp65 (NF-κBp65) in the iris and ciliary body. Our findings show that GTE is a potent anti-inflammatory agent against the inflammation of EIU, and suggest a potential use in treatment of acute uveitis.

Chitosan oligosaccharides attenuate ocular inflammation in rats with experimental autoimmune anterior uveitis

We investigated the protective effects and mechanisms of chitosan oligosaccharides (COS) on experimental autoimmune anterior uveitis (EAAU) in rats. EAAU was induced in Lewis rats by footpad and intraperitoneal injections of melanin-associated antigen. The rats received intraperitoneal injections of low-dose (5 mg/kg) or high-dose (10 mg/kg) COS or PBS daily after the immunization. The effects of COS were evaluated by determining the clinical scores and the morphology of the iris/ciliary body (ICB). The expression of inflammatory mediators was evaluated using western blot, immunofluorescence, and ELISA. Treatment with COS significantly attenuated the clinical scores and the leukocyte infiltration in the ICB in a dose-dependent manner. COS effectively reduced the expression of inflammatory mediators (TNF-α, iNOS, MCP-1, RANTES, fractalkine, and ICAM-1). Moreover, COS decreased the IκB degradation and p65 presence in the ICB, which resulted in the inhibition of NF-κB/DNA binding activity. In an in vitro study, sensitized spleen-derived lymphocytes of the COS-treated group showed less chemotaxis toward their aqueous humor and decreased secretion of the above inflammatory mediators in the culture media. COS treated EAAU by inhibiting the activation of NF-κB and reducing the expression of inflammatory mediators. COS might be a potential treatment for acute anterior uveitis.

Resolvin D1 reduces the immunoinflammatory response of the rat eye following uveitis

This study investigated whether the administration of resolvin D1 to rats with endotoxininduced uveitis (EIU) ameliorates the immuno-inflammatory profile of the eye. 24 h after the administration of 200 μg LPS into the footpad of Sprague-Dawley rats, severe changes of the structure of the eye occurred concomitantly with a severe inflammatory and immune response. These latter included strong infiltration of PMN leukocytes CD11b(+) T-lymphocytes CD4(+) and CD8(+) within the eye and a significant release of the cytokines/chemokines TNF-alpha, CXCL8, and RANTES too. Bolus of resolvin D1 (RvD1; 10-100-1000 ng/kg in 200 μL of sterile saline via the tail vein) significantly and dose-dependently (i) reduced the development of the ocular derangement caused by LPS; (ii) reduced the clinical score attributed to EIU; (iii) reduced the protein concentration and myeloperoxidase activity (MPO) in aqueous humor (AqH); and (iv) reduced neutrophils, T-lymphocytes, and cytokines within the eye.

Neuropeptide FF activates ERK and NF kappa B signal pathways in differentiated SH-SY5Y cells

Neuropeptide FF (NPFF) has been reported to play important roles in regulating diverse biological processes. However, little attention has been focused on the downstream signal transduction pathway of NPFF. Here, we used the differentiated neuroblastoma cell line, dSH-SY5Y, which endogenously expresses hNPFF2 receptor, to investigate the signal transduction downstream of NPFF. In particular we investigated the regulation of the extracellular signal-regulated protein kinase (ERK) and the nuclear factor kappa B (NF-κB) pathways by NPFF in these cells. NPFF rapidly and transiently stimulated ERK. H89, a selective inhibitor of cyclic AMP-dependent protein kinase A (PKA), inhibited the NPFF-activated ERK pathway, indicating the involvement of PKA in the NPFF-induced ERK activation. Down-regulation of nitric oxide synthases also attenuated NPFF-induced ERK activation, suggesting that a nitric oxide synthase-dependent pathway is involved. Moreover, the core upstream components of the NF-κB pathway were also significantly activated in response to NPFF, suggesting that the NF-κB pathway is involved in the signal transduction pathway of NPFF. Collectively, these data demonstrate that nitric oxide synthases are involved in the signal transduction pathway of NPFF, and provide the first evidence for the interaction between NPFF and the NF-κB pathway. These advances in our interpretation of the NPFF pathway mechanism will aid the comprehensive understanding of its function and provide novel molecular insight for further study of the NPFF system.

Nitidine chloride inhibits LPS-induced inflammatory cytokines production via MAPK and NF-kappaB pathway in RAW 264.7 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Zanthoxylum nitidium (Roxb.) DC. has long been used as a traditional herbal medicine for inflammatory diseases such as rheumatic arthritis and peridentitis. However, the anti-inflammatory mechanism of Nitidine chloride has not been fully elucidated.

AIM OF THE STUDY

To determine the anti-inflammatory effects and mechanism of Nitidine chloride (NTD), a pentacyclic alkaloid is isolated from the root of Z. nitidium, in murine macrophages.

MATERIALS AND METHODS

Anti-inflammatory properties of NTD were investigated using lipopolysaccharide (LPS)-stimulated Raw 264.7 macrophages as in vitro model. The pro-inflammatory cytokines were evaluated by real-time RT-PCR and ELISA. Furthermore, intracellular signaling pathways were analyzed by Western blot and Immunofluorescence staining using specific antibodies.

RESULTS

NTD significantly reduced the production of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and IL-6 in both RNA and protein level. Moreover, transcriptional activity of NF-кB as well as the phosphorylation of mitogen-activated protein kinases (MAPKs) in LPS-treated RAW 264.7 was significantly inhibited by NTD in a dose dependent manner. These results suggested that NTD exerts an anti-inflammatory property by inhibiting TNF-α, IL-1β, and IL-6 production in association with reduced NF-κB and MAPK signaling pathways in RAW 264.7 cells.

CONCLUSION

These results suggested that NTD exerts an anti-inflammatory property by inhibiting TNF-α, IL-1β, and IL-6 production in association with reduced NF-κB and MAPK signaling pathways in RAW 264.7 cells. Nitidine chloride inhibits LPS-induced TNF alpha, IL-1beta and IL-6 production via the suppression of phosphorylation of MAPK and the translocation of p65. In addition, these results revealed a novel role of NTD in regulation of inflammatory diseases.