Preventive Effect of YGDEY from Tilapia Fish Skin Gelatin Hydrolysates against Alcohol-Induced Damage in HepG2 Cells through ROS-Mediated Signaling Pathways

Bioactive peptides as a novel strategy to prevent alcoholic liver injury

Alcohol intake has become one of the leading risks to human health and wellness, among which acute and/or chronic alcohol-induced liver injury is a leading threaten, with few therapeutic options other than abstinence. In recent years, studies suggested that certain bioactive peptides from food sources could represent natural and safe alternatives for the prevention of alcoholic liver injury. Hence, this chapter focus on the advanced research on bioactive peptides exerting hepatoprotective activity against alcoholic liver injury. The main sources of protein, strategies for the preparation of hepatoprotective hydrolysates and peptides, underlying mechanisms of peptides on hepatoprotection, and possible structure-activity relationship between peptides and hepatoprotective activity were summarized and discussed, aiming to give a systematic insight into the research progress of hepatoprotective peptides. However, more efforts would be needed to give a clearer insight into the underlying mechanisms and structure-activity relationship before using hepatoprotective peptides as functional food ingredients or dietary supplements.

Effects of Mactra chinenesis Peptides on Alcohol-Induced Acute Liver Injury and Intestinal Flora in Mice

Food-borne bioactive peptides have shown promise in preventing and mitigating alcohol-induced liver injury. This study was the first to assess the novel properties of Mactra chinenesis peptides (MCPs) in mitigating acute alcoholic liver injury in mice, and further elucidated the underlying mechanisms associated with this effect. The results showed that MCPs can improve lipid metabolism by modulating the AMPK signaling pathway, decreasing fatty acid synthase activity, and increasing carnitine palmitoyltransferase 1a activity. Meanwhile, MCPs ameliorate inflammation by inhibiting the NF-κB activation, leading to reduced levels of pro-inflammatory cytokines (tumor necrosis factor-α and interleukin-1β). Additionally, a 16S rDNA sequencing analysis revealed that MCPs can restore the balance of gut microbiota and increase the relative abundance of beneficial bacteria. These findings suggest that supplementation of MCPs could attenuate alcohol intake-induced acute liver injury, and, thus, may be utilized as a functional dietary supplement for the successful treatment and prevention of acute liver injury.

Aflatoxin B1 inhibited the development of primary myoblasts of grass carp (Ctenopharyngodon idella) by degrading extracellular matrix

According to the International Agency for Research on Cancer (IARC), aflatoxin B1 (AFB1) has been recognized as a major contaminant in food and animal feed and which is a common mycotoxin with high toxicity. Previous research has found that AFB1 inhibited zebrafish muscle development. However, the potential mechanism of AFB1 on fish muscle development is unknown, so it is necessary to conduct further investigation. In the present research, the primary myoblast of grass carp was used as a model, we treated myoblasts with AFB1 for 24 h. Our results found that 5 μM AFB1 significantly inhibited cell proliferation and migration (P < 0.05), and 10 μM AFB1 promoted lactate dehydrogenase (LDH) release (P < 0.05). Reactive oxygen species (ROS), protein carbonyl (PC) and malondialdehyde (MDA) levels were increased in 15, 5 and 10 μM AFB1 (P < 0.05), respectively. Catalase (CAT), glutathione peroxidase (GPx) and total superoxide dismutase (T-SOD) activities were decreased in 10, 10 and 15 μM AFB1 (P < 0.05), respectively. Furthermore, 15 μM AFB1 induced oxidative damage by Nrf2 pathway, also induced apoptosis in primary myoblast of grass carp. Meanwhile, 15 μM AFB1 decreased MyoD gene and protein expression (P < 0.05). Importantly, 15 μM AFB1 decreased the protein expression of collagen Ⅰ and fibronectin (P < 0.05), and increased the protein levels of urokinase plasminogen activator (uPA), matrix metalloproteinase 9 (MMP-9), matrix metalloproteinase 2 (MMP-2), and p38 mitogen-activated protein kinase (p38MAPK) (P < 0.05). As a result, our findings suggested that AFB1 damaged the cell morphology, induced oxidative damage and apoptosis, degraded ECM components, in turn inhibiting myoblast development by activating the p38MAPK/urokinase-type plasminogen activator (uPA)/matrix metalloproteinase (MMPs)/extracellular matrix (ECM) signaling pathway.

Rg3-loaded P407/CS/HA hydrogel inhibits UVB-induced oxidative stress, inflammation and apoptosis in HaCaT cells

UVB radiation can damage human skin, whereas Ginsenoside Rg3, the active ingredient in red ginseng that is processed from ginseng (Panax ginseng C.A. Meyer), could inhibit UVB induced cell damage through anti-oxidation. Meanwhile, P407/CS/HA hydrogel has significant biomedical applications as carriers of drugs. However, the beneficial effects of Rg3-loaded hydrogel (Rg3-Gel) on human HaCaT keratinocytes induced by UVB have rarely been reported. In our study, Rg3 was loaded into hydrogel and the effect of Rg3-Gel against UVB‑induced Hacat cells damages was determined by measuring its ability to alleviate UVB‑induced elevation of oxidative stress, pro-inflammatory and apoptotic response. We found that the treatment with Rg3-Gel inhibited the generation of intracellular ROS and MDA and upregulated the expression of antioxidant enzymes SOD and GSH-Px which were inhibited by UVB exposure. Increased levels of pro-inflammatory cytokines TNF‑α, COX‑2, iNOS and IL‑1β following UVB irradiation were suppressed by the introduction of Rg3-Gel. Additionally, the level of Bcl-2 was decreased and the expression of Bax and Caspase3 were enhanced by Rg3-Gel treatment. In conclusion, Rg3-Gel equipped with the synergistic effect of Rg3 and hydrogel has an effective inhibitory effect on UVB-induced oxidative stress, inflammatory and apoptosis.

Protective effects of Aureobasidium pullulans lysate on UV-damaged human skin fibroblasts and HaCaT cells

BACKGROUND

Aureobasidium pullulans (A. pullulans) has a wide range of applications. Ultraviolet (UV) rays from the sun can cause skin photoaging. In order to explore the protective effect and application potential of A. pullulans lysate on UV-damaged human skin fibroblasts (HSF) and HaCaT Cells, this study investigates the anti-aging and anti-inflammatory effects of A. pullulans lysate as well as the mechanism of anti-oxidative stress at the cellular and molecular levels through cytotoxicity experiments, enzyme-linked immunosorbent assays (ELISA), and real-time quantitative PCR (RT-qPCR).

RESULTS

The experimental results have shown that the A. pullulans lysate can effectively reduce the loss of extracellular matrix components (EMC), such as collagen and hyaluronic acid (HA). It is also capable of scavenging excess reactive oxygen species (ROS) from the body, thereby increasing the activity of catalase, decreasing the overexpression of intracellular matrix metalloproteinases (MMPs), enhancing the gene expression of metalloproteinase inhibitors (TIMPs), and decreasing the level of inflammatory factors, reducing UV-induced apoptosis of HaCaT cells. Meanwhile, oxidative stress homeostasis is also regulated through the Nrf2/Keap1 and MAPK signaling pathways.

CONCLUSIONS

This study shows that the A. pullulans lysate has the potential to resist photoaging.

Scutellarin prevents acute alcohol-induced liver injury via inhibiting oxidative stress by regulating the Nrf2/HO-1 pathway and inhibiting inflammation by regulating the AKT, p38 MAPK/NF-κB pathways

Alcoholic liver disease (ALD) is the most frequent liver disease worldwide, resulting in severe harm to personal health and posing a serious burden to public health. Based on the reported antioxidant and anti-inflammatory capacities of scutellarin (SCU), this study investigated its protective role in male BALB/c mice with acute alcoholic liver injury after oral administration (10, 25, and 50 mg/kg). The results indicated that SCU could lessen serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and improve the histopathological changes in acute alcoholic liver; it reduced alcohol-induced malondialdehyde (MDA) content and increased glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) activity. Furthermore, SCU decreased tumor necrosis factor-‍α (TNF-‍α), interleukin-6 (IL-6), and IL-‍1β messenger RNA (mRNA) expression levels, weakened inducible nitric oxide synthase (iNOS) activity, and inhibited nucleotide-binding oligomerization domain (NOD)‍-like receptor protein 3 (NLRP3) inflammasome activation. Mechanistically, SCU suppressed cytochrome P450 family 2 subfamily E member 1 (CYP2E1) upregulation triggered by alcohol, increased the expression of oxidative stress-related nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) pathways, and suppressed the inflammation-related degradation of inhibitor of nuclear factor-‍κB (NF-‍κB)‍-‍α (IκBα) as well as activation of NF‍-‍κB by mediating the protein kinase B (AKT) and p38 mitogen-activated protein kinase (MAPK) pathways. These findings demonstrate that SCU protects against acute alcoholic liver injury via inhibiting oxidative stress by regulating the Nrf2/HO-1 pathway and suppressing inflammation by regulating the AKT, p38 MAPK/NF-κB pathways.

Purification and Identification of Peptides from Oyster (Crassostrea hongkongensis) Protein Enzymatic Hydrolysates and Their Anti-Skin Photoaging Effects on UVB-Irradiated HaCaT Cells

This study aimed to purify and identify antiphotoaging peptides from oyster (Crassostrea hongkongensis) protein enzymatic hydrolysates (OPEH) and to investigate the possible mechanism underlying its antiphotoaging effect. Multiple methods (Ultrafiltration, G25 Chromatography, RP-HPLC, and LC/MS/MS) had been used for this purpose, and eventually, two peptides, including WNLNP and RKNEVLGK, were identified. Particularly, WNLNP exerted remarkable antiphotoaging effect on the UVB-irradiated HaCaT photoaged cell model in a dose-dependent manner. WNLNP exerted its protective effect mainly through inhibiting ROS production, decreasing MMP-1 expression, but increasing extracellular pro-collagen I content. Furthermore, WNLNP downregulated p38, JNK, ERK, and p65 phosphorylation in the MAPK/NF-κB signaling pathway and attenuated bax over-expressions but reversed bcl-2 reduction in UVB- irradiated HaCaT cells. The molecular docking analysis showed that WNLNP forms five and seven hydrogen bonds with NF-κB (p65) and MMP-1, respectively. This study suggested that a pentapeptide WNLNP isolated from OPEH had great potential to prevent and regulate skin photoaging.

Glycyrrhizic acid Poly(D,L-lactide-co-glycolide) nanoparticles: anti-aging cosmeceutical formulation for topical applications

Glycyrrhizic acid (GA) is one of the components of licorice roots (Glycyrrhiza glabra L.). GA is a triterpenoid saponin can be used as a medicinal plant with its antiallergic, antiviral, anti-inflammatory, anti-ulcer, hepatoprotective, anticancer, anti-oxidation activities and several other therapeutic properties. The aim of this study is to develop an anti-aging formulation for topical application containing GA. In this context, GA-loaded Poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) were prepared using the double emulsion method, and were characterized by various spectroscopic methods. The efficacy of GA-PLGA NPs was evaluated with in vitro and in silico methods. The encapsulation efficiency and loading capacity were calculated. The in vitro release study was conducted, and the GA release profile was determined. The genotoxic activity of GA and GA-PLGA NPs was evaluated by the Ames test using TA98 and TA100 mutant strains of Salmonella typhimurium. The cytotoxic potential of GA-PLGA NPs was evaluated on the HaCaT cell line using the MTT assay. According to the genotoxicity and cytotoxicity results, it was found that the GA-PLGA NP formulation did not exhibit genotoxic and cytotoxic effects. Moreover, the efficacy of GA in preventing UVB-induced photo-aging in HaCaT cells and the clarification of the molecular mechanism of GA binding to MMPs were revealed by molecular docking analysis. In addition, through molecular dynamics (MD) analysis, the binding interaction of GA with MMPs in a dynamic system, and protein-ligand stability were predicted as a result of 50 ns MD simulation studies considering various analysis parameters. Finally, it was evaluated that GA-PLGA nanoformulation might be used as an alternative anti-aging skin care product candidate via topical application.

Bi-phasic effect of gelatin in myogenesis and skeletal muscle regeneration

Skeletal muscle regeneration requires extracellular matrix (ECM) remodeling, including an acute and transient breakdown of collagen that produces gelatin. Although the physiological function of this process is unclear, it has inspired the application of gelatin to injured skeletal muscle for a potential pro-regenerative effect. Here, we investigated a bi-phasic effect of gelatin in skeletal muscle regeneration, mediated by the hormetic effects of reactive oxygen species (ROS). Low-dose gelatin stimulated ROS production from NADPH oxidase 2 (NOX2) and simultaneously upregulated the antioxidant system for cellular defense, reminiscent of the adaptive compensatory process during mild stress. This response triggered the release of the myokine IL-6, which stimulates myogenesis and facilitates muscle regeneration. By contrast, high-dose gelatin stimulated ROS overproduction from NOX2 and the mitochondrial chain complex, and ROS accumulation by suppressing the antioxidant system, triggering the release of TNFα, which inhibits myogenesis and regeneration. Our results have revealed a bi-phasic role of gelatin in regulating skeletal muscle repair mediated by intracellular ROS, the antioxidant system and cytokine (IL-6 and TNFα) signaling.

Summary: Application of high- and low-dose gelatin to skeletal muscle revealed a bi-phasic role of gelatin in regulating skeletal muscle repair, which has translational implications for regenerative medicine.

Efficacy of Zhuyu Pill Intervention in a Cholestasis Rat Model: Mutual Effects on Fecal Metabolism and Microbial Diversity

Cholestasis is a clinical condition resulting from impaired bile flow. Currently, patients with cholestasis face several barriers in seeking diagnosis and treatment. Zhuyu Pill (ZYP) is an ancient classic formula of the Coptis-Evodia herb couples (CEHC), and has been used for cholestasis treatment in the clinic, however, its underlying biological activity in cholestasis remain to be clarified. In this study, an α-naphthyl-isothiocyanate (ANIT, 50 mg/kg)-induced rat model of cholestasis was treated with ZYP. Serum biochemical indices and histopathological evaluation was performed, together with the metabolomics analyses of feces and 16S rDNA sequencing of the fecal microbiota. We evaluated the anti-cholestatic activity of ZYP and investigated the mechanisms underlying its correlation with fecal microbiota and fecal metabolite regulation. The relationships between biochemical indices and changes in gene expression associated with liver injury, levels fecal metabolites, and composition of fecal microbiota were analyzed. The results showed that both high (1.2 g/kg) and low (0.6 g/kg) doses of ZYP could effectively improve biochemical parameters in the blood of cholestasis-induced rat models; the intervention effect of high dose ZYP was superior to that that of lower dose ZYP. Based on a metabolomics test of fecal samples, significantly altered metabolites in the ANIT and ZYP treatment group were identified. In total, 734 metabolites were differentially expressed, and whose biological functions were mainly associated with amino acid metabolism, steroid hormone biosynthesis, and bile secretion. In addition, sequencing of the 16S rDNA unit in fecal samples revealed that the ZYP could improve the fecal microbiota dysbiosis that ANIT had induced. Therefore, we conclude that ANIT altering of blood biochemical and metabolic profiles and of fecal microbiota could effectively be alleviated with ZYP treatment. This study contributes to the “TCM wisdom” applied in clinical diagnosis and treatment of cholestasis.

Antioxidant Mechanisms of the Oligopeptides (FWKVV and FMPLH) from Muscle Hydrolysate of Miiuy Croaker against Oxidative Damage of HUVECs

In this work, the antioxidant mechanisms of bioactive oligopeptides (FWKVV and FMPLH) from protein hydrolysate of miiuy croaker muscle against H₂O₂-damaged human umbilical vein endothelial cells (HUVECs) were researched systemically. The finding demonstrated that the HUVEC viability treated with ten antioxidant peptides (M1 to M10) at 100.0 μM for 24 h was not significantly affected compared with that of the normal group (P < 0.05). Furthermore, FWKVV and FMPLH at 100.0 μM could very significantly enhance the viabilities (75.89 ± 1.79% and 70.03 ± 4.37%) of oxidative-damaged HUVECs by H₂O₂ compared with those of the model group (51.66 ± 2.48%) (P < 0.001). The results indicated that FWKVV and FMPLH played their protective functions through increasing the levels of antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreasing the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and nitric oxide (NO) in oxidative-damaged HUVECs in a dose-dependent manner. In addition, the comet assay revealed that FWKVV and FMPLH could dose-dependently protect deoxyribonucleic acid (DNA) from oxidative damage in the HUVEC model. These results suggested that antioxidant pentapeptides (FWKVV and FMPLH) could serve as potential antioxidant additives applied in the food products, pharmaceuticals, and health supplements.

The Inhibition Effect of the Seaweed Polyphenol, 7-Phloro-Eckol from Ecklonia Cava on Alcohol-Induced Oxidative Stress in HepG2/CYP2E1 Cells

The liver is vulnerable to oxidative stress-induced damage, which leads to many diseases, including alcoholic liver disease (ALD). Liver disease endanger people's health, and the incidence of ALD is increasing; therefore, prevention is very important. 7-phloro-eckol (7PE) is a seaweed polyphenol, which was isolated from Ecklonia cava in a previous study. In this study, the antioxidative stress effect of 7PE on HepG2/CYP2E1 cells was evaluated by alcohol-induced cytotoxicity, DNA damage, and expression of related inflammation and apoptosis proteins. The results showed that 7PE caused alcohol-induced cytotoxicity to abate, reduced the amount of reactive oxygen species (ROS) and nitric oxide (NO), and effectively inhibited DNA damage in HepG2/CYP2E1 cells. Additionally, the expression levels of glutathione (GSH), superoxide dismutase (SOD), B cell lymphoma 2 (Bcl-2), and Akt increased, while γ-glutamyltransferase (GGT), Bcl-2 related x (Bax), cleaved caspase-3, cleaved caspase-9, nuclear factor-κB (NF-κB), and JNK decreased. Finally, molecular docking proved that 7PE could bind to BCL-2 and GSH protein. These results indicate that 7PE can alleviate the alcohol-induced oxidative stress injury of HepG2 cells and that 7PE may have a potential application prospect in the future development of antioxidants.

Intracellular ethanol-mediated oxidation and apoptosis in HepG2/CYP2E1 cells impaired by two active peptides from seahorse (Hippocampus kuda bleeler) protein hydrolysates via the Nrf2/HO-1 and akt pathways

Seahorse (Hippocampus kuda Bleeler) are representative marine species in aquaculture, with special value of medicine and food. In this study, the protective effects of two peptides from seahorse hydrolysates (SHP-1 and SHP-2) against ethanol-mediated oxidative stress in HepG2/CYP2E1 cells were investigated. Firstly, SHP-1 and SHP-2 presented no cytotoxicity. Compared with the ethanol-treated groups, SHP-1 and SHP-2 increased cell viability in a concentration-dependent manner. Secondly, SHP-1 and SHP-2 markedly reduced intracellular reactive oxygen species (ROS) generation, gamma-glutamyltranspeptidase (GGT) activity, and tumor necrosis factor-α (TNF-α) levels and remarkably enhanced superoxide dismutase (SOD) and glutathione (GSH) activities. SHP-1 and SHP-2 also down-regulated the expressions of GGT, bax, c-caspase-8/-9/-3, p-Akt, p-IκB-α, p-p65, p-ERK, and p-p38 but up-regulated SOD, GSH, NF-E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and bcl-2 levels, as revealed by Western blot analysis. Moreover, SHP-1 and SHP-2 increased the mitochondrial membrane potential (MMP), reduced DNA damage, and suppressed the nuclear translocation of p65. These results suggest that two peptides from seahorse hydrolysates can be considered a potential functional biomaterial and further improve the use value of seahorse in aquaculture.

CUX2, BRAP and ALDH2 are associated with metabolic traits in people with excessive alcohol consumption

Molecular mechanisms that prompt or mitigate excessive alcohol consumption could be partly explained by metabolic shifts. This genome-wide association study aims to identify the susceptibility gene loci for excessive alcohol consumption by jointly measuring weekly alcohol consumption and γ-GT levels. We analysed the Taiwan Biobank data of 18,363 Taiwanese people, including 1945 with excessive alcohol use. We found that one or two copies of the G allele in rs671 (ALDH2) increased the risk of excessive alcohol consumption, while one or two copies of the C allele in rs3782886 (BRAP) reduced the risk of excessive alcohol consumption. To minimize the influence of extensive regional linkage disequilibrium, we used the ridge regression. The ridge coefficients of rs7398833, rs671 and rs3782886 were unchanged across different values of the shrinkage parameter. The three variants corresponded to posttranscriptional activity, including cut-like homeobox 2 (a protein coded by CUX2), Glu504Lys of acetaldehyde dehydrogenase 2 (a protein encoded by ALDH2) and Glu4Gly of BRCA1-associated protein (a protein encoded by BRAP). We found that Glu504Lys of ALDH2 and Glu4Gly of BRAP are involved in the negative regulation of excessive alcohol consumption. The mechanism underlying the γ-GT-catalytic metabolic reaction in excessive alcohol consumption is associated with ALDH2, BRAP and CUX2. Further study is needed to clarify the roles of ALDH2, BRAP and CUX2 in the liver–brain endocrine axis connecting metabolic shifts with excessive alcohol consumption.

The Protective Effect of the Polysaccharide Precursor, D-Isofloridoside, from Laurencia undulata on Alcohol-Induced Hepatotoxicity in HepG2 Cells

Alcoholic liver disease (ALD) threatens human health, so it is imperative that we find ways to prevent or treat it. In recent years, the study of polysaccharides has shown that they have different kinds of bioactivities. Among them are many biological effects that have been attributed to polysaccharide precursors. D-Isofloridoside (DIF) is one of the polysaccharide precursors from the marine red alga Laurencia undulata. This study evaluated the effect of DIF on alcohol-induced oxidative stress in human hepatoma cells (HepG2). As a result, DIF attenuated alcohol-induced cytotoxicity, reduced the amount of intracellular reactive oxygen species (ROS), and effectively reduced alcohol-induced DNA damage in HepG2 cells. In addition, a western blot showed that, after DIF treatment, the expression levels of glutathione (GSH), superoxide dismutase (SOD), and B-cell lymphoma-2 (bcl-2) increased, while the expression levels of γ-glutamyl transferase (GGT), BCL2-associated X (bax), cleaved caspase-3, and mitogen-activated protein kinase (p38 and c-Jun N-terminal kinase) signal transduction proteins reduced. This showed that DIF may protect cells by reducing the amount of intracellular ROS and inhibiting intracellular oxidative stress and apoptotic processes. Finally, molecular docking demonstrated that DIF can bind to SOD, GGT, B-cell lymphoma-2, and bax proteins. These results indicated that DIF can protect HepG2 cells from alcohol-induced oxidative stress damage, making it an effective potential ingredient in functional foods.

Modified ZIF-8 Nanoparticles Attenuate Osteoarthritis by Reprogramming the Metabolic Pathway of Synovial Macrophages

Accumulating evidence suggests that activation of proinflammatory M1-type macrophages in the synovium plays a vital role in the progression of osteoarthritis (OA). Redundant nitric oxide (NO) and hydrogen peroxide (H₂O₂) are key factors that drive macrophages to polarize to the M1 type. Herein, modified zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) have been synthesized. By regulating intracellular gases and reprogramming the metabolism phenotype, modified NPs transformed macrophage polarization from proinflammatory M1 to anti-inflammatory M2 phenotype. Specifically, S-methylisothiourea hemisulfate salt was loaded into ZIF-8 NPs to inhibit inducible nitric oxide synthase, hence reducing NO production. Catalase was encapsulated to catalyze the production of oxygen (O₂) from H₂O₂. Results demonstrated that modified NPs were capable of catalyzing H₂O₂ to produce O₂ and eliminate NO, hence inhibiting hypoxia-inducible factor 1α, further rescuing mitochondrial function. Moreover, anti-CD16/32 antibody modification could prolong the retention time of NPs in knee joints of OA mice with anterior cruciate ligament transection. More significantly, modified NPs suppressed M1 macrophages and up-regulated M2 macrophage infiltration in the synovium, further inhibiting cartilage degeneration. This ZIF-8 NP-based gas regulation and metabolic reprogramming strategy may pave a new avenue for OA treatment.

Cytoprotective Effect of Antioxidant Pentapeptides from the Protein Hydrolysate of Swim Bladders of Miiuy Croaker (Miichthys miiuy) against H2O2-Mediated Human Umbilical Vein Endothelial Cell (HUVEC) Injury

In our previous research, ten antioxidant pentapeptides including FYKWP, FTGMD, GFEPY, YLPYA, FPPYERRQ, GFYAA, FSGLR, FPYLRH, VPDDD, and GIEWA were identified from the hydrolysate of miiuy croaker (Miichthys miiuy) swim bladder. In this work, their protective function on H₂O₂-induced oxidative damage to human umbilical vein endothelial cells (HUVECs) was studied. Results indicated that there was no significant difference in the HUVEC viability between the normal group and the treated groups with the 10 pentapeptides at the concentration of 100 μM for 24 h (p < 0.05). Furthermore, FPYLRH of 100 μg/mL extremely significantly (p < 0.001) increased the viability (80.58% ± 5.01%) of HUVECs with H₂O₂-induced oxidative damage compared with that of the model group. The protective mechanism indicated that FPYLRH could extremely significantly (p < 0.001) increase the levels of superoxide dismutase (SOD) (211.36 ± 8.29 U/mg prot) and GSH-Px (53.06 ± 2.34 U/mg prot) and decrease the contents of reactive oxygen species (ROS) (139.1 ± 11.8% of control), malondialdehyde (MDA) (13.66 ± 0.71 nM/mg), and nitric oxide (NO) (4.36 ± 0.32 µM/L) at the concentration of 100 μM in HUVECs with H₂O₂-induced oxidative damage compared with those of the model group. In addition, FPYLRH dose-dependently protected DNA in oxidative damage HUVECs model. These results suggested that FPYLRH could significantly attenuate the H₂O₂-induced stress injury in HUVECs and might be used as a potential natural antioxidant in the functional food industries.

Protective effect of polysaccharides of sea cucumber Acaudina leucoprocta on hydrogen peroxide-induced oxidative injury in RAW264.7 cells

The aim of this experiment was to investigate the protective effects of polysaccharides of sea cucumber Acaudina leucoprocta (ALP) against hydrogen peroxide (H₂O₂) induced oxidative injury in RAW264.7 cells. Analysis of monosaccharide composition and structure of one fraction from ALP (ALP_N) were analyzed by High Performance Liquid Chromatography (HPLC) and Fourier Transform Infrared Spectoscopy (FT-IR). The results showed that ALP_N contain sulfate groups, which is sulfated polysaccharides. The results from MTT assay indicated that ALP_N could markedly increase viability of cells compared with RAW264.7 cells exposed to H₂O₂. Moreover, ALP_N significantly increased the levels of catalase (CAT), glutathione peroxidase (GSH-P_X) and superoxide dismutase (SOD), decreased the production of malondialdehyde (MDA) and lactate dehydrogenase (LDH) in RAW264.7 cells. The data from RT-PCR showed that ALP_N (300 μg/mL) could increase the gene expression levels of SOD1 and GPX1. ALP_N could also observably increase the protein expression level of Nrf2 and decrease the protein expression level of Keap1 with western blot. Collectively, this study suggested that polysaccharides of sea cucumber Acaudina leucoprocta (ALP) could effectively protect RAW264.7 cells against H₂O₂-induced oxidative injury. This protection mechanism may be related to activation of the Nrf2/Keap1 signaling pathway.

A Peptide YGDEY from Tilapia Gelatin Hydrolysates Inhibits UVB-mediated Skin Photoaging by Regulating MMP-1 and MMP-9 Expression in HaCaT Cells

In this study, we investigated the protective effects of a peptide (YGDEY, Tyr-Gly-Asp-Glu-Tyr) isolated from tilapia skin gelatin hydrolysates (TGHs), against UVB-induced photoaging in human keratinocytes (HaCaT) cells. Results showed that YGDEY significantly decreased levels of intracellular reactive oxygen species (ROS), increased antioxidant factors (Superoxide Dismutase, SOD and Glutathione, GSH) expression and maintained balance between GSH and GSSG in HaCaT cells. Comet assay shows that YGDEY can protect DNA from oxidative damage. Furthermore, it significantly inhibited MMP-1 (collagenase) and MMP-9 (gelatinase) expression and increased Type I procollagen production. In addition, the molecular docking study showed that YGDEY may form active sites with MMP-1 and MMP-9. Moreover, Western blot analysis was utilized to measure the protein levels of UVB-induced mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) signaling pathways. Therefore, these results suggested that YGDEY has a therapeutic effectiveness in prevention of UVB-induced cellular damage, and it is a candidate worthy of being developed as a potential natural antioxidant and food additive.