Cytoprotective Peptides from Blue Mussel Protein Hydrolysates: Identification and Mechanism Investigation in Human Umbilical Vein Endothelial Cells Injury.

Cardiovascular disease represents a leading cause of mortality and is often characterized by the emergence of endothelial dysfunction (ED), a physiologic condition that takes place in the early progress of atherosclerosis. In this study, two cytoprotective peptides derived from blue mussel chymotrypsin hydrolysates with the sequence of EPTF and FTVN were purified and identified. Molecular mechanisms underlying the cytoprotective effects against oxidative stress which lead to human umbilical vein endothelial cells (HUVEC) injury were investigated. The results showed that pretreatment of EPTF, FTVN and their combination (1:1) in 0.1 mg/mL significantly reduced HUVEC death due to H2O2 exposure. The cytoprotective mechanism of these peptides involves an improvement in the cellular antioxidant defense system, as indicated by the suppression of the intracellular ROS generation through upregulation of the cytoprotective enzyme heme oxygenase-1. In addition, H2O2 exposure triggers HUVEC damage through the apoptosis process, as evidenced by increased cytochrome C release, Bax protein expression, and the elevated amount of activated caspase-3, however in HUVEC pretreated with peptides and their combination, the presence of those apoptotic stimuli was significantly decreased. Each peptide showed similar cytoprotective effect but no synergistic effect. Taken together, these peptides may be especially important in protecting against oxidative stress-mediated ED.

Insertion of gallic acid onto chitosan promotes the differentiation of osteoblasts from murine bone marrow-derived mesenchymal stem cells.

Chitosan, a naturally occurring biodegradable and biocompatible polymer, has found use as a food additive, nutraceuticals, and functional foods in recent years. In this study, gallic acid-g-chitosan (GAC) was prepared by the insertion of GA onto plain chitosan (PC) via free radical-mediated grafting and its osteogenic effects were investigated in murine bone marrow-derived mesenchymal stem cells (mBMMSCs). Structural characterization of PC and GAC was performed using 1H NMR and FT-IR spectroscopy. The amount of GA successfully grafted onto PC was 111 mg GA/g GAC via the Folin-Ciocalteu's method. While PC and GAC promoted the increase in alkaline phosphatase activity and mineralization, GAC increased these factors significantly more than PC, indicating that the grafting of GA onto chitosan increased its osteogenic potential. Mechanistic study revealed that GAC activated Wnt1 and Wnt3a mRNA and protein expression as well as increased the translocation of ß-catenin into the nucleus and upregulated the expression of ß-catenin targeted genes including Runx2, osterix, type I collagen and cyclin D1. In addition, DKK-1, a Wnt antagonist, decreased GAC-mediated osteoblast differentiation in mBMMSCs through blocking the Wnt/ß-catenin signaling pathway.

Cytoprotective Role of Edible Seahorse (Hippocampus abdominalis)-Derived Peptides in H2O2-Induced Oxidative Stress in Human Umbilical Vein Endothelial Cells.

Oxidative stress-induced endothelial dysfunction is strongly linked to the pathogenesis of cardiovascular diseases. A previous study revealed that seahorse hydrolysates ameliorated oxidative stress-mediated human umbilical vein endothelial cells (HUVECs) injury. However, the responsible compounds have not yet been identified. This study aimed to identify cytoprotective peptides and to investigate the molecular mechanism underlying the cytoprotective role in H2O2-induced HUVECs injury. After purification by gel filtration and HPLC, two peptides were sequenced by liquid chromatography-tandem mass spectrometry as HGSH (436.43 Da) and KGPSW (573.65 Da). The synthesized peptides and their combination (1:1 ratio) showed significant HUVECs protection effect at 100 µg/mL against H2O2-induced oxidative damage via significantly reducing intracellular reactive oxygen species (ROS). Two peptides and their combination treatment resulted in the increased heme oxygenase-1 (HO-1), a phase II detoxifying enzyme, through the activation of nuclear transcription factor-erythroid 2-related factor (Nrf2). Additionally, cell cycle and nuclear staining analysis revealed that two peptides and their combination significantly protected H2O2-induced cell death through antiapoptotic action. Two peptides and their combination treatment led to inhibit the expression of proapoptotic Bax, the release of cytochrome C into the cytosol, the activation of caspase 3 by H2O2 treatment in HUVECs, whereas antiapoptotic Bcl-2 expression was increased with concomitant downregulation of Bax/Bcl-2 ratio. Taken together, these results suggest that seahorse-derived peptides may be a promising agent for oxidative stress-related cardiovascular diseases.

Blue Mussel-Derived Peptides PIISVYWK and FSVVPSPK Trigger Wnt/ß-Catenin Signaling-Mediated Osteogenesis in Human Bone Marrow Mesenchymal Stem Cells.

Marine-derived bioactive peptides have shown potential bone health promoting effects. Although various marine-derived bioactive peptides have potential nutraceutical or pharmaceutical properties, only a few of them are commercially available. This study presented an osteogenic mechanism of blue mussel-derived peptides PIISVYWK and FSVVPSPK as potential bone health promoting agents in human bone marrow-derived mesenchymal stem cells (hBMMSCs). Alkaline phosphatase (ALP) activity and mineralization were stimulated using PIISVYWK and FSVVPSPK as early and late markers of osteogenesis in a concentration-dependent manner. Western blot and RT-qPCR results revealed that PIISVYWK and FSVVPSPK increased osteoblast differentiation of hBMMSCs by activating canonical Wnt/ß-catenin signaling-related proteins and mRNAs. Immunofluorescence images confirmed nuclear translocation of ß-catenin in osteogenic differentiation. Treatment with the pharmacological inhibitor DKK-1 blocked PIISVYWK- and FSVVPSPK-induced ALP activity and mineralization, as well as mRNA expression of the canonical Wnt/ß-catenin signaling pathway in hBMMSC differentiation into osteoblasts. These findings suggested that PIISVYWK and FSVVPSPK promoted the canonical Wnt/ß-catenin signaling pathway in osteogenesis of hBMMSCs. Blue mussel-derived PIISVYWK and FSVVPSPK might help develop peptide-based therapeutic agents for bone-related diseases.

Anti-Osteoporotic Effects of Antioxidant Peptides PIISVYWK and FSVVPSPK from Mytilus edulis on Ovariectomized Mice.

Numerous amounts of evidence suggest that bioactive peptides with diverse physiological activities can be nutraceuticals or potential drug candidates. In this study, blue mussel-derived antioxidant peptides PIISVYWK and FSVVPSPK were subjected to evaluate their osteogenic effect in mouse bone marrow mesenchymal stem cells (mBMMSCs) followed by an in vivo anti-osteoporotic effect. Treatment of PIISVYWK and FSVVPSPK on mBMMSCs stimulated alkaline phosphatase activity and calcification. Western blot results revealed that PIISVYWK and FSVVPSPK increased the expression of bone morphogenetic protein-2/4 (BMP-2/4) followed by upregulating p-Smad1/5, type I collagen, and transcription factors including Runx2 and osterix in mBMMSCs. Two peptides also activated the phosphorylation of MAPKs (p-p38, p-ERK, and p-JNK). Treatment of MAPK inhibitors significantly inhibited the BMP signaling pathway, indicating that PIISVYWK and FSVVPSPK stimulated osteoblast differentiation of mBMMSCs through the MAPK-dependent BMP signaling pathway. The anti-osteoporotic effect of PIISVYWK and FSVVPSPK in ovariectomized (OVX) mice was investigated. Treatment of PIISVYWK and FSVVPSPK for ten weeks showed a notable anti-osteoporotic effect in OVX mice via increasing bone mineral density and other bone parameters compared to OVX mice without peptides. Serum analysis also showed that treatment of PIISVYWK and FSVVPSPK completely reduced osteocalcin and ALP (alkAline phosphatase) activity. Taken together, these results suggest that PIISVYWK and FSVVPSPK could be health-promoting functional food ingredients against osteoporosis.

Low molecular weight blue mussel hydrolysates inhibit adipogenesis in mouse mesenchymal stem cells through upregulating HO-1/Nrf2 pathway.

Blue mussel proteins are a good source of bioactive peptides. In this study, blue mussel hydrolysate (BMH) with anti-adipogenic effect in mouse mesenchymal stem cells (mMSC) was produced by peptic hydrolysis at 1:500 of pepsin/substrate ratio for 120 min. Additionally, BMH with below 1 kDa (BMH < 1 kDa) showed the highest anti-adipogenic effect in mMSC. BMH < 1 kDa increased lipolysis and down-regulated adipogenic transcription factors including peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein 1 (SREBP1). Generation of intracellular reactive oxygen species during adipogenesis was markedly decreased by BMH < 1 kDa treatment, which is attributed to the up-regulation of heme oxygenase-1 (HO-1) through Nrf2 translocation into the nucleus. Moreover, ZnPP, HO-1 inhibitor, treatment abolished BMH < 1 kDa-mediated HO-1 expression and anti-adipogenic effect in mMSCs through down-regulating adipogenic transcription factors. Taken together, BMH < 1 kDa may be a potential ingredient of nutraceuticals and/or functional foods in ameliorating obesity.

Ark shell protein-derived bioactive peptides promote osteoblastic differentiation through upregulation of the canonical Wnt/ß-catenin signaling in human bone marrow-derived mesenchymal stem cells.

In this study, the stimulating effect of ark shell protein-derived peptides AWLNH and PHDL on osteoblast differentiation in human bone marrow-derived mesenchymal stem cells (hBMMSCs) and its molecular mechanism was investigated. The hBMMSCs were cultured with two peptides and osteogenic markers were analyzed. Results showed that enhanced ALP activity and calcification were detected in the presence of AWLNH and PHDL. Based on western blotting, RT-qPCR, and immunostaining analysis, AWLNH and PHDL are specific for osteoblast differentiation of hBMMSCs through activating the canonical Wnt/ß-catenin signaling pathway followed by activating Runx2, osterix, and type I collagen. Loss-of-function assay with DKK-1, a Wnt antagonist, showed that the canonical Wnt/ß-catenin signaling was essential for AWLNH and PHDL-induced osteogenesis in hBMMSCs. These findings suggested that AWLNH and PHDL can stimulate osteoblast differentiation of hBMMSCs via upregulating the canonical Wnt/ß-catenin signaling and may be useful for a potential nutraceuticals or pharmaceuticals to treat osteoporosis. PRACTICAL APPLICATIONS: Ark shell is a popular foodstuff in Korea. However, biological effects of its protein and peptide have not been explored in many ways. This study demonstrated that ark shell protein-derived peptides promoted osteoblast differentiation in hBMMSCs through upregulating the canonical Wnt/ß-catenin signaling. The results of this study could be a basis to promote its application as functional foods and/or nutraceuticals.

In Vivo Hepatoprotective Effects of a Peptide Fraction from Krill Protein Hydrolysates against Alcohol-Induced Oxidative Damage.

BACKGROUND: Krill (Euphausia superba) represent the largest animal biomass on earth, and are a rich source of high-quality protein with essential amino acids. Krill-derived peptides are renowned for their antioxidant activities. Hence, these peptides may have protective effects against oxidative stress. Alcoholic liver disease is a prevalent cause of death worldwide. The present study explores the hepatoprotective effects of krill peptide hydrolysate fractions against ethanol-induced liver damage in BALB/c mice. METHODS: Hydrolysis was carried out by mimicking the gastrointestinal digestion environment and the filtrate was fractionated based on molecular weight (<1 kDa, 1-3 kDa, and >3 kDa). The 1-3 kDa fraction (KPF), which indicated the highest antioxidant effect, was further investigated for its effect on weight and survival rate increase in mice and its influence on serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and liver cholesterol levels. Moreover, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) levels were measured, followed by Nrf2 and HO-1 expression. Histopathology studies were conducted to assess hepatic tissue damage. RESULTS: KPF enhanced the weight and survival rate of mice while reducing serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and liver cholesterol levels. Moreover, KPF upregulated SOD, CAT, and GPx in liver tissues, while downregulating tumor necrosis factor α and interleukin-6 mRNA expression. KPF further increased Nrf2 and HO-1 expression and suppressed ethanol-induced apoptotic proteins in the liver. Histopathology of KPF-treated mice showed less hepatic tissue damage compared to ethanol-treated mice. CONCLUSIONS: Hydrolysates and bioactive peptides prepared from krill can be employed as functional foods to enhance liver function and health. Further investigations of KPF could lead to the development of functional foods.

Two novel peptides from ark shell protein stimulate osteoblast differentiation and rescue ovariectomy-induced bone loss.

Osteoporosis is a common bone disease resulting from imbalance between bone formation and bone resorption. Currently, anti-resorptive agents that inhibit bone resorption are the most available drugs on the market. Biosphosphonates, anti-resorptive drugs most commonly used to treat osteoporosis, are limited by their side effects for long-term continuous treatment. It is important to develop appropriate therapeutic stragegies capable of promoting bone formation to counteract osteoporotic bone loss. Thus, anabolic agents that stimulate bone formation are undoubtedly of interest. Here, we purified and identified two novel osteogenic peptides AWLNH and PHDL from ark shell protein hydrolysates. AWLNH and PHDL stimulated osteoblast differentiation via mitogen-activated protein kinase (MAPK) and bone morphogenetic protein-2 (BMP-2) pathways. The activation of BMP-2 pathway stimulated by AWLNH and PHDL was abolished by treating noggin, BMP antagonist, in bone marrow-derived mesenchymal stem cells (BMMSCs), but not the phosphorylation of JNK1/2, ERK1/2, and p38 MAPK. However, treatment with MAPK inhibitors in BMMSCs downregulated the expression of BMP-2 and p-Smad1/5 and inhibited alkaline phosphatase activity. The dominant inhibitory effects by JNK inhibitor and ERK inhibitor are observed. In ovariectomized (OVX) mice, a reduction of femoral bone mineral density (BMD) was significantly observed, however, AWLNH and PHDL (0.2 mg/kg/per day) injection restored BMD as well as the osteoporotic conditions in OVX mice. Moreover, the increased serum osteocalcin and alkaline phosphatase activity in OVX mice were significantly reduced in AWLNH and PHDL injected-OVX mice. These results suggest that two novel osteogenic peptides AWLNH and PHDL could be attractive therapeutic agents for osteoporosis treatment.

Bone health-promoting bioactive peptides.

Bioactive peptides, derivatives of proteins, show versatile biological effects and represent potential health-promoting agents as functional food ingredients and/or nutraceuticals. Bone health depends on the balance between bone formation and resorption. When the balance is disrupted, bone diseases such as osteoporosis and fragility fractures may result. Accumulating evidence suggests that peptides derived from endogenous proteins and food proteins enhance bone health. This article reviews the literature on peptides exhibiting bone health-promoting effects. Possible biochemical mechanisms and production of these peptides are briefly discussed. PRACTICAL APPLICATIONS: Bioactive peptides are derived from food proteins via enzymatic hydrolysis, are already commercially available. In vitro and in vivo bone health-promoting effects of bioactive peptides have been shown in several animal models of osteoporosis and fractures. Thus, peptides can be used as functional food ingredients and/or nutraceuticals. However, their exact role and safety in human subjects should be evaluated prior to commercialization.

Lotus (Nelumbo nucifera) seed protein isolate exerts anti-inflammatory and antioxidant effects in LPS-stimulated RAW264.7 macrophages via inhibiting NF-κB and MAPK pathways, and upregulating catalase activity.

Lotus seed has long been used in traditional medicine and cuisine. In this study, lotus seed protein (LSP) was isolated and evaluated its anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. LSP isolate (LSPI) treatment in LPS-stimulated RAW264.7 macrophages resulted in the significant (p < 0.05) decrease of NO production by downregulation of the expressions of mRNA and protein, including inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). In addition, LSPI treatment attenuated the production of reactive oxygen species (ROS) through increasing catalase activity, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1ß in LPS-stimulated RAW264.7 macrophages. Furthermore, LPS stimulation in RAW264.7 macrophages caused the translocation of nuclear factor-kappa B (NF-κB) into the nucleus and the phosphorylation of mitogen-activated protein kinase (MAPK) but these stimulations were abolished by LSPI treatment.

Amino Acid Composition, Antioxidant, and Cytoprotective Effect of Blue Mussel (Mytilus edulis) Hydrolysate through the Inhibition of Caspase-3 Activation in Oxidative Stress-Mediated Endothelial Cell Injury.

Enhanced oxidative stress plays a central role in promoting endothelial dysfunction, leading to the development of atherosclerosis. In this study, we investigated the protective effects of the hydrolysates derived from blue mussel (Mytilus edulis) against H2O2-mediated oxidative injury in human umbilical vein endothelial cells (HUVECs). The blue mussel hydrolysates were prepared by enzymatic hydrolysis with eight proteases, and blue mussel-α-chymotrypsin hydrolysate (BMCH) showed the highest antioxidant activities in DPPH radical scavenging, ABTS⁺ radical scavenging, and ORAC value compared to those of the other hydrolysates. BMCH also inhibited Cu2+-mediated low density lipoprotein (LDL) oxidation. Treatment of H2O2 resulted in the decreased HUVEC viability whereas pre-treatment with BMCH increased HUVEC viability and reduced reactive oxygen species (ROS) generation. BMCH pre-treatment increased cellular antioxidant capacities, including levels of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) against H2O2-mediated oxidative stress in HUVECs. Flow cytometry and western blot analysis revealed that BMCH pre-treatment significantly reduced H2O2-mediated HUVEC apoptosis through inhibition of caspase-3 activation. Real-time-qPCR analysis showed that BMCH down-regulated expression of p53 and caspase-3 genes, as well as decreased the bax/bcl-2 ratio. Taken together, these results indicate that BMCH may be useful as functional food ingredients for protecting endothelial dysfunction or related disease.

Sea Squirt (Halocynthia roretzi) Hydrolysates Induce Apoptosis in Human Colon Cancer HT-29 Cells through Activation of Reactive Oxygen Species.

Recent evidence provides that seafood has a lot of health benefits due to its unique bioactive compounds. Sea squirt is widely cultured and consumed as a foodstuff in Korea; however, seldom reports with reference to bioactivities are available until now. In this study, edible part of sea squirt was hydrolyzed by pepsin and its hydrolysates was evaluated for anticancer effect on human colon cancer HT-29 cells. Sea squirt hydrolysates (SSQ) reduced HT-29 cell viability. Treatment with SSQ resulted in the increase in reactive oxygen species (ROS) generation followed by disruption of mitochondrial membrane potential (MMP). Flow cytometry analysis revealed that SSQ induced G2/M phase arrest and apoptosis evidenced by Hoechst 33342 staining. Levels of mRNA expression by real-time polymerase chain reaction (PCR) showed that treatment with SSQ in HT-29 cells upregulated expression of p53, bax, and caspase-3 genes and downregulated expression of bcl-2 gene. Protein level of cytochrome c into cytosol and caspase-3 by Western blotting were also increased by treatment with SSQ in HT-29 cells. These results suggest that SSQ may be useful for functional food ingredients and/or nutraceuticals.

Protective effect of enzymatic hydrolysates from seahorse (Hippocampus abdominalis) against H2O2-mediated human umbilical vein endothelial cell injury.

Oxidative stress-mediated endothelial dysfunction and LDL oxidation have been implicated in the pathogenesis of atherosclerosis. Thus, the protection of the endothelial cells against oxidative stress-mediated injury and the inhibition of LDL oxidation by the use of antioxidants are a good strategy against atherosclerosis development. Here, we investigated the protective effect and the inhibition of LDL oxidation of seahorse H. abdominalia hydrolysates by Alcalase (SHAH). SHAH showed higher antioxidant activities by measuring DPPH, ABTS+, and ORAC assays than the other hydrolysates. SHAH reduced the formation of thiobarbituric acid reactive substance in Cu2+-induced LDL oxidation. In human umbilical vein endothelial cell (HUVEC), SHAH ameliorated H2O2-mediated HUVEC injury through the restoration of antioxidant enzyme activities and glutathione. In addition, SHAH inhibited HUVEC apoptosis through the down-regulation of caspase-3 and p53 and the increase bcl-2/bax ratio. These results suggested that seahorse H. abdominalia could be developed as potential agents for atherosclerosis.

Blue mussel (Mytilus edulis) protein hydrolysate promotes mouse mesenchymal stem cell differentiation into osteoblasts through up-regulation of bone morphogenetic protein.

Seafood provides a range of health benefits due to its high-protein level. In this study, the osteogenic effect of blue mussel (Mytilus edulis) protein hydrolysates (BMPH) on osteoblast differentiation were examined using mouse mesenchymal stem cells (MSCs). A preparation we called BMPH<1kDa which showed the highest osteogenic effect in MSCs, was prepared by peptic hydrolysis. BMPH<1kDa treatment stimulated osteoblast differentiation with alkaline phosphatase (ALP) induction, osteocalcin and type I collagen activity as well as calcium deposition. Osteoblast differentiation stimulated by BMPH<1kDa treatment was achieved by expression of osteogenic lineage markers, such as bone morphogenetic protein-2 (BMP-2), and downstream signal and transcription factors, including p-Smad1/5/8, Dlx5, runt-related transcription factor 2 (Runx2), and osterix. BMPH<1kDa activated phosphorylation of mitogen-activated protein kinases. Adding noggin, a BMP antagonist, inhibited BMPH<1 kDa-induced ALP activity in MSCs. Taken together, our results show that BMPH<1kDa promoted osteoblast differentiation by activating BMP-2.

Protective Effects of An Water Extracts Prepared from Loliolus beka Gray Meat Against H2O2-Induced Oxidative Stress in Chang Liver Cells and Zebrafish Embryo Model.

In this study, we first evaluated protective effects of Loliolus beka in a human liver cell line and zebrafish embryo model with its anti-oxidant activity. First, we prepared the water extract from L. beka meat (LBMW) at room temperature for 24 h and revealed it consisted of a rich taurine. LBMW exhibited the scavenging effects against 2,2-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and hydrogen peroxide (H2O2) as well as the high value of oxygen radical absorbance capacity (ORAC). Also, the hydroxyl radical-induced DNA damage was dose-dependently reduced by the treatment of LBMW. In addition, LBMW showed no cytotoxicity and reduced the production of reactive oxygen species (ROS) in H2O2-treated hepatocytes. Moreover, LBMW regulated the expression of an anti-apoptotic molecule, Bcl-2 and the expression of pro-apoptotic molecules, Bax and PARP in H2O2-treated hepatocytes as well as the increment of antioxidant mediated-HO-1 and Nrf2 protein expression. In further study, LBMW improved the survival rate and decreased the production of ROS in H2O2-treated zebrafish embryo model. Therefore, our results suggest that Loliolus beka has protective effects against H2O2-induced oxidative stress and may be used as a potential source for functional foods.

Hepatoprotective Effects of Xylose-Taurine Reduced Against Hydrogen Peroxide-Induced Oxidative Stress in Cultured Hepatocytes.

In this study, Xylose-Taurine reduced (X-T-R) was synthesized to enhance biological activities. Hence, we investigated the hepatoprotective effects of X-T-R against H2O2-induced hepatocyte damage and apoptosis. The results showed that X-T-R led to the cytoprotective effect against H2O2-induced oxidative stress in cultured hepatocytes such as the improvement of cell viability and the reduction of reactive oxygen species (ROS) production. Additionally, pre-treatment with X-T-R increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), NAD(P)H dehydrogenase:quinone 1 (NQO1) and heme oxygenase 1 (HO-1) in cultured hepatocytes. Furthermore, X-T-R protected the cells against apoptosis via regulating the expression level of Bcl-2/Bax as well as the activation of caspase-3. According to the results obtained, X-T-R may be a bio-material for the therapy of hepatic diseases.

Protective Effects of Xylose-Taurine Reduced against Damages Caused by Oxidative Stress in Zebrafish Embryos In Vivo Model.

The zebrafish (Danio rerio) is useful and convenient vertebrate models in various studies in human disease and drug discovery. In this present study, we first evaluated whether Xylose-Taurine reduced (X-T-R), a taurine derivate protects zebrafish embryos against oxidative stress caused by AAPH (2,2'-Azobis(2-amidinopropane) dihydrochloride). First of all, we selected the concentration of X-T-R showing no toxicity in zebrafish embryos. We identified that X-T-R significantly increased the survival of zebrafish embryo reduced by treatment of AAPH. Also, X-T-R effectively inhibited the productions of reactive oxygen species (ROS) and nitric oxide (NO) as well as the formation of cell death in zebrafish embryos. Moreover, X-T-R down-regulated the expression levels of Bax, caspase-3, caspase-9 and p53 known as pro-apoptotic molecules, whereas up-regulated those of Bcl-2, an anti-apoptotic molecule in AAPH-treated zebrafish embryos. From these results, this study reveals that X-T-R, a taurine derivate might be a potential protector against various damages caused by oxidative stress.

Anti-inflammatory Effects of Galactose-Taurine Sodium Salt in LPS-Activated RAW 264.7 Cells.

In this study, we synthesized Galactose-Taurine sodium salt (G-T) as a functional food ingredient to enhance biological activities of taurine. Also, anti-inflammatory effects of G-T were investigated in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. G-T found to reduce the generations of the LPS-stimulated nitric oxide (NO) and prostaglandin E2 (PGE2) via down-regulating the expression levels of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2). Also, G-T reduced the secretion of inflammatory cytokines including interleukin (IL)-1ß, IL-6 and tumor necrosis factor (TNF-α) in LPS-treated RAW 264.7 cells. Finally, we identified that G-T inhibits the activation of nuclear factor-κB (NF-κB) and the phosphorylation of inhibitor κB (IκB)-α. From these results, this study first suggests that G-T could be considered as an effective anti-inflammatory agent.

Hepatoprotective effect of chitosan-caffeic acid conjugate against ethanol-treated mice.

The chitosan-caffeic acid (CCA) conjugate shows a hepatoprotective effect against oxidative stress-induced hepatic damage in cultured hepatocytes. The objective of this study is the verification of the hepatoprotective effect of the CCA in vivo against ethanol-induced liver injury in mice. The administration of ethanol resulted in the increase of the serum-aminotransferase activities (AST and ALT), triglycerides, total cholesterol, and lipid peroxidation. The CCA co-administration, however, significantly (p<0.05) ameliorated these serum biomarkers. The antioxidant-enzyme activities in the liver tissue, including those of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), were significantly decreased by a chronic ethanol administration, whereas the hepatic lipid-peroxidation level was increased. Moreover, the chronic ethanol administration elevated the gene expression of pro-inflammatory cytokines such as tumor-necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the liver tissue. The CCA co-administration, however, significantly (p<0.05) increased the activities of the SOD, CAT, and GPx and caused the down-regulation of the TNF-α- and IL-6-gene expressions in the liver tissue. An histopathologic evaluation also supported the hepatoprotective effect of the CCA against ethanol-induced hepatotoxicity in the mice.