Protection mechanism of Se-containing protein hydrolysates from Se-enriched rice on Pb2+-induced apoptosis in PC12 and RAW264.7 cells

Ultrasonic extraction of Moringa oleifera seeds polysaccharides: Optimization, purification, and anti-inflammatory activities

Natural polysaccharides exhibit numerous beneficial properties, such as antioxidant, antitumor, hypoglycemic, and hypolipidemic activities. Moringa oleifera seeds are of high dietary and therapeutic value which drew a lot of attention. However, the regulation effect on anti-inflammatory activity of polysaccharides remains to be studied. Herein, novel bioactive polysaccharides (MOSP-1) were extracted from Moringa oleifera seeds, and the anti-inflammatory properties of MOSP-1 were uncovered. Ultrasound-assisted extraction (UAE) was used to prepare the polysaccharides with optimized conditions (70 °C, 43 min, and liquid-solid-ratio 15 mL/g). Then, DEAE-Sepharose Fast Flow columns were applied to isolate and purify MOSP-1. Rhamnose, arabinose, galactose, and glucose were identified as the monosaccharide constituents of MOSP-1, with a molecular weight of 5.697 kDa. Their proportion in molarity was 1:0.183:0.108:0.860 and 8 types of glycosidic linkages were discovered. Bioactive assays showed that MOSP-1 possessed scavenging activities against DPPH and ABTS radicals, confirming its potential antioxidation efficacy. In vitro experiments revealed that MOSP-1 could reduce the expression of inflammation-related cytokines, inhibit the activation of ERK, JNK, and p38 (the MAPK signaling pathway), and enhance phagocytic functions. This study indicates that polysaccharides (MOSP-1) from Moringa oleifera seeds with anti-inflammatory properties may be used for functional food and pharmaceutical product development.

Food-derived Peptides as Promising Neuroprotective Agents: Mechanism and Therapeutic Potential

Many food-derived peptides have the potential to improve brain health and slow down neurodegeneration. Peptides are produced by the enzymatic hydrolysis of proteins from different food sources. These peptides have been shown to be involved in antioxidant and anti-inflammatory activity, neuro-transmission modulation, and gene expression regulation. Although few peptides directly affect chromatin remodeling and histone alterations, others indirectly affect the neuroprotection process by interfering with epigenetic changes. Fish-derived peptides have shown neuroprotective properties that reduce oxidative stress and improve motor dysfunction in Parkinson's disease models. Peptides from milk and eggs have been found to have anti-inflammatory properties that reduce inflammation and improve cognitive function in Alzheimer's disease models. These peptides are potential therapeutics for neurodegenerative diseases, but more study is required to assess their efficacy and the underlying neuroprotective benefits. Consequently, this review concentrated on each mechanism of action used by food-derived peptides that have neuroprotective advantages and applications in treating neurodegenerative diseases. This article highlights various pathways, such as inflammatory pathways, major oxidant pathways, apoptotic pathways, neurotransmitter modulation, and gene regulation through which food-derived peptides interact at the cellular level.

Selenium-Enriched Soybean Peptides as Novel Organic Selenium Compound Supplements: Inhibition of Occupational Air Pollution Exposure-Induced Apoptosis in Lung Epithelial Cells

The occupational groups exposed to air pollutants, particularly PM2.5, are closely linked to the initiation and advancement of respiratory disorders. The aim of this study is to investigate the potential protective properties of selenium-enriched soybean peptides (Se-SPeps), a novel Se supplement, in mitigating apoptosis triggered by PM2.5 in A549 lung epithelial cells. The results indicate a concentration-dependent reduction in the viability of A549 cells caused by PM2.5, while Se-SPeps at concentrations of 62.5-500 µg/mL showed no significant effect. Additionally, the Se-SPeps reduced the production of ROS, proinflammatory cytokines, and apoptosis in response to PM2.5 exposure. The Se-SPeps suppressed the PM2.5-induced upregulation of Bax/Bcl-2 and caspase-3, while also restoring reductions in p-Akt in A549 cells. The antiapoptotic effects of Se-SPeps have been found to be more effective compared to SPeps, SeMet, and Na2SeO3 when evaluated at an equivalent protein or Se concentration. Our study results furnish evidence that supports the role of Se-SPeps in reducing the harmful effects of PM2.5, particularly in relation to its effect on apoptosis, oxidative stress, and inflammation.

Selenoproteins in Health

Selenium (Se) is a naturally occurring essential micronutrient that is required for human health. The existing form of Se includes inorganic and organic. In contrast to the inorganic Se, which has low bioavailability and high cytotoxicity, organic Se exhibits higher bioavailability, lower toxicity, and has a more diverse composition and structure. This review presents the nutritional benefits of Se by listing and linking selenoprotein (SeP) functions to evidence of health benefits. The research status of SeP from foods in recent years is introduced systematically, particularly the sources, biochemical transformation and speciation, and the bioactivities. These aspects are elaborated with references for further research and utilization of organic Se compounds in the field of health.

Selenium alleviates lead-induced CIK cells pyroptosis and inflammation through IRAK1/TAK1/IKK pathway

The toxic heavy metal lead is widely found in rivers and soils as an environmental pollutant, posing a threat to the health of aquatic organisms. Selenium is an essential trace element and a powerful antioxidant that has been shown to have anti-inflammatory and antioxidant properties as well as alleviating heavy metal poisoning. Many studies have shown that lead poisoning produces inflammatory responses and damage to the kidneys of a wide range of animals, but the effects on cellular pyroptosis and immune function and selenium antagonism in CIK cells are not clear. In this study, 500 μM Pb and 20 nM Se were applied to grass carp kidney cells, and the results showed that Pb exposure to CIK cells resulted in oxidative stress, activation of the IRAK1/TAK1/IKK pathway, up-regulation of the expression of cellular pyroptosis markers GSDMD and NLRP3, and cellular pyroptosis of CIK cells, as well as up-regulation of IL-1β and IL-18, and the generation of cellular inflammatory response. In contrast, Se treatment significantly reduced the ROS level, the expression of cellular pyroptosis markers GSDMD, NLRP3 and inflammatory element IL-1β and IL-18. Taken together, Se alleviated cellular pyroptosis and immune dysfunction caused by Pb exposure through oxidative stress and activation of the IRAK1/TAK1/IKK pathway. This study complements the harmful effects of the heavy metal Pb on fish and the real-life application of selenium in the healthy culture of fish as a reference will be provided.

Molecular Mechanisms of Selenium Mitigating Lead Toxicity in Chickens via Mitochondrial Pathway: Selenoproteins, Oxidative Stress, HSPs, and Apoptosis

Lead (Pb), a hazardous heavy metal, can damage the health of organisms. However, it is not clear whether Pb can damage chicken cerebellums and thalami. Selenium (Se), an essential nutrient for organisms, has a palliative effect on Pb poisoning in chickens. In our experiment, a model of chickens treated with Pb and Se alone and in combination was established to investigate the molecular mechanism of Se alleviating Pb-caused damage in both chicken cerebellums and thalami. Our morphological results indicated that Pb caused apoptotic lesions, such as mitochondrial and nuclear damage. Further, the anti-apoptotic gene Bcl-2 decreased; on the contrary, four pro-apoptotic genes (p53, Bax, Cyt c, and Caspase-3) increased under Pb treatment, meaning that Pb caused apoptosis via the p53-Cyt c-Caspase-3 pathway. Furthermore, we further demonstrated that Pb elevated four HSPs (HSP27, HSP40, HSP70, and HSP90), as well as HSP70 took part in the molecular mechanism of Pb-caused apoptosis. In addition, we found that Pb exposure led to oxidative stress via up-regulating the oxidant H2O2 and down-regulating four antioxidants (CAT, SOD, GST, and GPx). Moreover, Pb decreased three Se-containing factors (Txnrd1, Txnrd2, and Txnrd3), further confirming that Pb caused oxidative stress. Interestingly, Se supplementation reversed the above changes caused by Pb and alleviated Pb-induced oxidative stress and apoptosis. A time dependency was demonstrated for Bcl-2, Bax, and Cyt c in the cerebellums, as well as CAT, GPx, and p53 in the thalami of Pb-exposed chickens. HSP70 in cerebellums and HSP27 in thalami were more sensitive than those in thalami and cerebellums, respectively, under Pb exposure. Pb-induced apoptosis of thalami was more severe than cerebellums. In conclusion, after Pb treatment, Txnrds mediated oxidative stress, oxidative stress up-regulated HSPs, and finally, HSP70 triggered apoptosis. Se supplementation antagonized Pb-induced oxidative stress and apoptosis via the mitochondrial pathway and selenoproteins in chicken cerebellums and thalami. This study provides new information for the mechanism of environmental pollutant poisoning and the detoxification of Se on abiotic stress.

Protective effects of tree peony seed protein hydrolysate on Cd-induced oxidative damage, inflammation and apoptosis in zebrafish embryos

The objective of this study was to investigate protective effects of tree peony seed protein hydrolysate by Alcalase (AL-TPSPH) on oxidative damage, inflammation and apoptosis using Cd-induced zebrafish embryos. Zebrafish embryos were treated with either Cd (2 μg/L) or AL-TPSPH (25, 50 and 75 μg/mL) alone or in combination of both from 4 to 144 h post fertilization (hpf). The effects of these treatments on developments, antioxidant parameters and mRNA expression of genes related to oxidative damage, inflammation and apoptosis were examined. The results showed that co-treatment with Cd and AL-TPSPH significantly increased hatching and survival rates and decreased malformation rates of zebrafish embryos compared with Cd treatment alone group (P < 0.05). Cd-induced increase of MDA content, decreases of T-AOC content, GSH/GSSG ratio and activities of SOD, CAT and GPx in zebrafish embryos were modified upon treatment with AL-TPSPH. AL-TPSPH treatment significantly suppressed Cd-induced down-regulations of the antioxidant gene expressions (Mn-sod, Cat and GPx1a) in zebrafish embryos (P < 0.05). AL-TPSPH also prevented Cd-induced up-regulations of pro-inflammatory cytokine (TNF-α, IL-1β and IFN-γ) expressions. Moreover, AL-TPSPH inhibited Cd-induced up-regulations of pro-apoptotic genes (C-jun, Caspase-3 and Caspase-9) in zebrafish embryos. Collectively, these results indicated that AL-TPSPH could reduce Cd-induced oxidative damage, inflammation and apoptosis in zebrafish embryos, suggesting its future applications as functional food or pharmaceutical ingredient.

Purification and characterization of Se-enriched Grifola frondosa glycoprotein, and evaluating its amelioration effect on As3+ -induced immune toxicity

BACKGROUND

Selenium (Se)-enriched glycoproteins have been a research highlight for the role of both Se and glycoproteins in immunoregulation. Arsenic (As) is a toxicant that is potentially toxic to the immune function and consequently to human health. Several reports suggested that Se could reduce the toxicity of heavy metals. Moreover, more and more nutrients in food had been applied to relieve As-induced toxicity. Hence glycoproteins were isolated and purified from Se-enriched Grifola frondosa, and their preliminary characteristics as well as amelioration effect and mechanism on As³⁺ -induced immune toxicity were evaluated.

RESULTS

Four factions, namely Se-GPr11 (electrophoresis analysis exhibited one band: 14.32 kDa), Se-GPr22 (two bands: 20.57 and 31.12 kDa), Se-GPr33 (three bands: 15.08, 20.57 and 32.78 kDa) and Se-GPr44 (three bands: 16.73, 32.78 and 42.46 kDa), were obtained from Se-enriched G. frondosa via DEAE-52 and Sephacryl S-400 column. In addition, Se-GPr11 and Se-GPr44 are ideal proteins that contain high amounts of almost all essential amino acids. Thereafter, the RAW264.7 macrophage model was adopted to estimate the effect of Se-GPr11 and Se-GPr44 on As³⁺ -induced immune toxicity. The results showed that the pre-intervention method was the best consequent and the potential mechanisms were, first, by improving the oxidative stress state (enhancing the activity of superoxide dismutase and glutathione peroxidase, decreasing the levels of reactive oxygen species and malondialdehyde); secondly, through nuclear factor-κB and mitogen-activated protein kinase-mediated upregulation cytokines (interleukin-2 and interferon-γ) secretion induced by As³⁺ .

CONCLUSION

The results suggested Se-enriched G. frondosa may be a feasible supplement to improve health level of the As³⁺ pollution population. © 2021 Society of Chemical Industry.

Structure and pro-inflammatory activities of bran polysaccharides from a novel wheat kernel

In this study, the structure and pro-inflammatory activities of water-soluble wheat bran polysaccharides (WBP) were evaluated. WBP were heteropolysaccharides consisting 60.34% arabinoxylan as the main component and 31.80% mannose residues characterized with the instrumental analyses. The result of cellular experiment displayed that WBP had significant pro-inflammatory activities by increasing the concentration of nitric oxide (NO) and up-regulating the inflammatory cytokine expressions of inducible nitric oxide synthase (iNOS), interleukin-1β (IL-1β), cyclooxygenase-2 (COX-2), and tumor necrosis factor-α (TNF-α). WBP mediated macrophages RAW 264.7 pro-inflammatory response through phosphatidylinositol 3 hydroxykinase/protein kinase B (PI3K/Akt) signaling pathway by significantly promoting Akt and phosphoinositide-dependent kinase 1 (PDK1) phosphorylations. Meanwhile, the expression of related phosphorylated proteins JNK and ERK1/2 was significantly up-regulated which suggested that WBP played pro-inflammatory roles by activating mitogen-activated protein kinases (MAPKs) signaling pathway. PRACTICAL APPLICATIONS: In recent years, wheat bran generally has the phenomenon of high yield and low utilization rate. Wheat bran has rich nutritional value and contains a lot of effective biologically active substances. Based on our findings, the water-soluble polysaccharides extracted from wheat bran have significant effects on regulating immunity and can be utilized as sources of natural immune modulators. The research can develop new functions of wheat bran polysaccharides, and improve processing utilization rate and product added value.

Selenium Supplementation Protects Against Lipopolysaccharide-Induced Heart Injury via Sting Pathway in Mice

Sepsis-induced myocardial dysfunctions are associated with high morbidity and mortality. Selenium, an essential trace element, has been reported to exert anti-inflammation, anti-oxidative stress, and anti-apoptosis. However, the protective effects of selenium on LPS-induced heart injury are still poorly illustrated. Therefore, in the present study, we sought to explore the effects of selenium pretreatment on LPS-induced myocardial injury in mice. We firstly found that selenium pretreatment significantly improved markers of myocardial injury and alleviated LPS-induced myocardial dysfunctions. Moreover, selenium supplementation reduced pro-inflammatory cytokines expression, decreased oxidative stress, and inhibited myocardial apoptosis. In addition, selenium supplementation inactivated the Sting pathway. In conclusion, our study suggests that selenium exerts protective effects on LPS-induced myocardial injury, and the underlying molecular mechanism may be related to the inactivation of Sting pathway, implying a potential therapy for sepsis-induced myocardial dysfunctions.

Characterization of Different Salt Forms of Chitooligosaccharides and Their Effects on Nitric Oxide Secretion by Macrophages

In this paper, chitooligosaccharides in different salt forms, such as chitooligosaccharide lactate, citrate, adipate, etc., were prepared by the microwave method. They were characterized by SEM, FTIR, NMR, etc., and the nitric oxide (NO) expression was determined in RAW 264.7 cells. The results showed that pure chitooligosaccharide was an irregular spherical shape with rough surface, and its different salt type products are amorphous solid with different honeycomb sizes. In addition to the characteristic absorption peaks of chitooligosaccharides, in FTIR, the characteristic absorption of carboxyl group, methylene group, and aromatic group in corresponding acid appeared. The characteristic absorption peaks of carbon in carboxyl group, hydrogen and carbon in methyl, methylene group, and aromatic group in corresponding acid also appeared in NMR. Therefore, the sugar ring structure and linking mode of chitooligosaccharides did not change after salt formation of chitooligosaccharides. Different salt chitooligosaccharides are completely different in promoting NO secretion by macrophages, and pure chitooligosaccharides are the best.

Selenium in cereals: Insight into species of the element from total amount

Selenium (Se) is a trace mineral micronutrient essential for human health. The diet is the main source of Se intake. Se-deficiency is associated with many diseases, and up to 1 billion people suffer from Se-deficiency worldwide. Cereals are considered a good choice for Se intake due to their daily consumption as staple foods. Much attention has been paid to the contents of Se in cereals and other foods. Se-enriched cereals are produced by biofortification. Notably, the gap between the nutritional and toxic levels of Se is fairly narrow. The chemical structures of Se compounds, rather than their total contents, contribute to the bioavailability, bioactivity, and toxicity of Se. Organic Se species show better bioavailability, higher nutritional value, and less toxicity than inorganic species. In this paper, we reviewed the total content of Se in cereals, Se speciation methods, and the biological effects of Se species on human health. Selenomethionine (SeMet) is generally the most prevalent and important Se species in cereal grains. In conclusion, Se species should be considered in addition to the total Se content when evaluating the nutritional and toxic values of foods such as cereals.

Selenium-Containing Proteins/Peptides from Plants: A Review on the Structures and Functions

Selenium is an essential microelement required for biological processes. Traditional selenium supplements (selenite and selenomethionine mainly) remain concerns due to toxicity and bioavailability. In recent decades, biofortification strategies have been applied to produce selenium-enriched edible plants to address the challenges of superior nutritional quality requirements. Plant-derived selenium-containing proteins/peptides offer potential health benefits beyond the basic nutritional requirements of Se. Highly nucleophilic seleno-amino acids, special peptide sequences, and favorable bioavailability contribute to the biological activities of selenium-containing proteins/peptides, such as antioxidant, antihypertensive, anti-inflammatory, and immunomodulatory effects. However, their applications on a commercial scale are insufficient owing to the complexity of purification and identification techniques and the sparse information on bioavailability and metabolism. In this review, selenium status, structural features, bioactivities, structure-activity relationships, and bioavailability, as well as the mechanisms underlying the bioactivities and metabolism of plant-derived selenium-containing proteins/peptides, are summarized and discussed for their nutraceutical use.

Genotoxic effects and proteomic analysis on Allium cepa var. agrogarum L. root cells under Pb stress

Ionic lead (Pb) in the environment has accumulated due to anthropogenic activities, causing a potential threat to plants and plant consumers. We conducted this study to reveal the molecular mechanism of Pb stress response in plants. The effects of Pb (5.0 and 15.0 μM) on mitosis, DNA replication, gene expression and proteins in root-tip cells of Allium cepa var. agrogarum L. were addressed. The results indicated that root growth was inhibited dramatically in Pb treatment groups. Chromosomal aberrations were observed and the mitotic index decreased during Pb treatments at different concentrations. The accumulation of reactive oxygen species (ROS) in onion roots was induced by Pb stress. Pb increased DNA damage and suppressed cell cycle progression. The above toxic effects got more serious with increasing Pb concentration and prolonging exposure time. A total of 17 proteins were expressed differentially between control and Pb exposure groups. Under Pb treatment, the decreased expression of Anx D1 indicated decreased defensive response; the decreased expression of SHMT1 indicated decreased respiration; the decreased expression of COMT2 indicated decreased response of other funtions; the increased expression of NDPK indicated increased transcription and protein synthesis; the increased expression of PR1 and CHI1 indicated increased pathogen invasion; the increased expression of ORC5 and MPK5 indicated the reduced DNA replicating activity; the decreased expression of POLD1 indicated the reduced DNA repair activity. Our results provide new insights at the proteomic level into the Pb-induced responses, defensive responses and toxic effects, and provide new molecular markers of the early events of plant responses to Pb toxicity.

The protective effect of soybean protein-derived peptides on apoptosis via the activation of PI3K-AKT and inhibition on apoptosis pathway

Soybean protein-derived peptides (SBP) are a rich source of various bioactive peptides with multiple health benefits. However, the prospective effects of SBP on human cells are still unclear. Therefore, this article investigated the effects of small molecular weight SBP on MG132-induced apoptosis in RAW264.7 cells. SBP inhibited MG132-induced apoptosis of RAW264.7 cells in a dose-dependent manner by flow cytometry. To further study its molecular mechanisms, Western blot analysis demonstrated that SBP could activate the PI3K-AKT pathway by increasing the phosphorylation of PI3K and AKT and inhibiting apoptosis pathway by downregulating the expressions of pro-apoptotic proteins of Bim, Bax, Fas, and Fasl and promoting the expressions of anti-apoptotic proteins of Bcl-xL and Bcl-2. These results indicated the protective effect of SBP on MG132-induced apoptosis in RAW264.7 cells.

Synergistic effects of Pb and repeated heat pulse on developmental neurotoxicity in zebrafish

Pollutant discharges to the aquatic environment often contain multiple environmental stressors, affecting aquatic organisms. To mimic the discharges from nuclear and industry facilities, the combined effects of two independent types of stressors, heavy metal Pb and repeated heat pulse were addressed in this study. We investigated the developmental toxicity of combined treatment, especially its toxic effects on zebrafish neurodevelopment. The normal embryos at 4 hpf were exposed to 0.2 mM of Pb dissolved in the bathing medium with different temperatures (30, 32, and 34 °C) and then maintained in an incubator at 28 °C. After performing above treatment once every 24 h for 6 days, we found that combined treatment significantly affected neural development, including loss of dopaminergic (DA) neurons and brain vasculature, disruption of locomotor activity and neurodevelopmental genes expression in a temperature-dependent manner as compared to the Pb alone exposure group, indicating that repeated heat pulse enhances these negative impacts induced by Pb. In contrast, no apparent toxicity was observed in repeated heat pulse alone groups, suggesting that Pb treatment reduces thermal tolerance in zebrafish, which emphasized the importance to evaluate synergistic effects of Pb and repeated heat pulse. Moreover, repeated heat pulse aggravated Pb-induced apoptosis in the zebrafish brain. Further study of the underlying mechanism suggested that Caspase 3 regulated apoptosis was involved in this process. Taken together, our findings shed light on the full understanding of toxic effects of discharges from industrial applications on living organisms and its environmental impact.

Selenium and zinc protections against metal-(loids)-induced toxicity and disease manifestations: A review

Metals are ubiquitous in the environment due to huge industrial applications in the form of different chemicals and from extensive mining activities. The frequent exposures to metals and metalloids are crucial for the human health. Trace metals are beneficial for health whereas non-essential metals are dangerous for the health and some are proven etiological factors for diseases including cancers and neurological disorders. The interactions of essential trace metals such as selenium (Se) and zinc (Zn) with non-essential metals viz. lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg) in biological system are very critical and complex. A huge number of studies report the protective role of Se and Zn against metal toxicity, both in animal and cellular levels, and also explain the numerous mechanisms involved. However, it has been considered that a tiny dyshomeostasis in the metals/trace metals status in biological system could induce severe deleterious effects that can manifest to numerous diseases. Thus, in this particular review, we have demonstrated the critical protection mechanism/s of Se and Zn against Cd, Pb, As and Hg toxicity in a one by one manner to clarify the up-to-date findings and perspectives. Furthermore, biomolecular consequences are comprehensively presented in light of particular cellular/biomolecular events which are somehow linked to a subsequent disease. The analyzed reports support significant protection potential of Se and Zn, either alone or in combination with other agents, against each of the abovementioned non-essential metals. However, Se and Zn are still not being used as detoxifying agents due to some unexplained reasons. We hypothesized that Se could be a potential candidate for detoxifying As and Hg regardless of their chemical speciations, but requires intensive clinical trials. However, particularly Zn-Hg interaction warrants more investigations both in animal and cellular level.

Hydroxypropyltrimethyl ammonium chloride chitosan activates RAW 264.7 macrophages through the MAPK and JAK-STAT signaling pathways

Hydroxypropyltrimethyl ammonium chloride chitosan (HACC) is a water-soluble derivative of chitosan. To investigate the immunostimulatory effects of HACC, quaternized chitosans with different molecular weights were prepared and their effects on RAW 264.7 macrophages were compared. The results showed that HACC promoted nitric oxide (NO) production in a molecular weight- and dose-dependent manner. Lower molecular weight HACC was more active in promoting NO production. Furthermore, flow cytometry analysis showed that HACC significantly promoted the production of interleukin-6 and tumor necrosis factor-α. These results were further demonstrated by quantitive real-time reverse transcription polymerase chain reaction and western blot analysis. Moreover, western blotting revealed that HACC induced the phosphorylation of extracellular signal-regulated kinase, c-Jun N-terminal kinase, p38, and signal transducer and activator of transcription (STAT) proteins. In conclusion, HACC activated RAW 264.7 cells through the mitogen-activated protein kinases and Janus kinase/STAT pathways.

Methionine enkephalin (MENK) inhibits human gastric cancer through regulating tumor associated macrophages (TAMs) and PI3K/AKT/mTOR signaling pathway inside cancer cells

This study was to explore the effect and mechanisms of anti- human gastric cancer by MENK in vitro and in vivo. The results showed in MENK-treated xenograft tissue, the percentage of M2-type macrophages decreased while M1-type macrophages increased. MENK increased the expression of M1-related cytokine TNF-α and attenuated the expression of M2-related cytokine IL-10 expression. MENK upregulated the expression of opioid receptor (OGFr), while it inhibited HGC27 and SGC7901 cells through blocking PI3K/AKT/mTOR signal pathway in vitro and in vivo. These effects of MENK could be cancelled when OGFr was knockdown. This indicates that binding to OGFr by MENK appears to be essential for the anti- GC cells. Therefore, it is concluded that MENK might skew macrophage toward M2 phenotype from M1 phenotype within tumor and induce cells apoptosis though blocking OGFr/PI3K/AKT/mTOR signaling pathway.

The novel mechanism of anticancer effect on gastric cancer through inducing G0/G1 cell cycle arrest and caspase-dependent apoptosis in vitro and in vivo by methionine enkephalin

Background

Gastric cancer (GC) is the second cause of cancer-related deaths. Methionine enkephalin (MENK), an endogenous opioid peptide, has immunological and antitumor activity.

Purpose

The aim of this work was to investigate whether MENK could exhibit activity against human GC in vitro and in vivo.

Materials and methods

Human GC cells were treated with MENK. Cell viability, colony formation, cell morphology, cell cycle, and apoptosis were assessed. The effects of MENK on gene expression of OGFr, Bax, BCL-2, caspase-3, PARP, Ki67, cyclin D1, c-myc, survivin were quantifed by qRT-PCR. Western blot was used to analyze the effects of MENK on protein expression of OGFr, Bax, BCL-2, caspase-3, PARP. The anti-tumor activity of MENK in gastic carcinoma was also investigated with animal experiments.

Results

The results indicate that MENK could significantly inhibit the growth of human GC cells SGC7901 and HGC27 in a concentration- and time-dependent manner, decrease the number of cell colonies, and arrest cell cycle in the G0/G1 phase by causing a decrease in Ki67, cyclin D1, and c-myc mRNA. Furthermore, MENK could induce tumor cell apoptosis associated with the upregulation of Bax, a corresponding downregulation of BCL-2 and survivin, and activation of caspase-3 and PARP. Moreover, MENK upregulated the expression of opioid receptors (OGFr) in SGC7901 and HGC27 cells. The interaction between MENK and OGFr in SGC7901 and HGC27 cells appears to be essential for the antitumor activity of MENK.

Conclusion

We conclude that MENK may be a potential drug for the treatment of GC.

Identification and assessment of residual levels of the main oxidation product of tert-butylhydroquinone in frying oils after heating and its cytotoxicity to RAW 264.7 cells

tert-Butylhydroquinone (TBHQ) losses and the residual levels of 2-tert-butyl-1,4-benzoquinone (TBBQ) in tripalmitin at different heating temperatures with or without reflux over various time intervals were investigated. Heating at 120 °C resulted in the slowest TBHQ loss and the highest TBBQ levels (52.61-62.93 μg/mL). The highest TBBQ concentrations (111.73-164.67 μg/mL) at 5 and 8 h and residual concentrations of 10.23-46.95 μg/mL during heating at 170 °C over 24 h were observed. Furthermore, the potential cytotoxicity of TBBQ to RAW 264.7 cells was evaluated with the MTT assay, Hoechst 33258 staining test, and flow cytometry analysis. Results indicate that TBBQ dose- and time-dependently decreased the growth of cells and inhibited DNA synthesis by regulating the S/G2 transition. The TBBQ concentration giving 50% inhibition in RAW 264.7 cells was 10.71 μg/mL. This threshold value is lower than the residual level of TBBQ in oil, indicating the necessity for concerns over the safety of fried food in terms of TBBQ residues.

Chemical composition of Cyclocarya paliurus polysaccharide and inflammatory effects in lipopolysaccharide-stimulated RAW264.7 macrophage

This study was designed to study the chemical composition of Cyclocarya paliurus polysaccharide and inflammatory effects in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage. A new elution (0.3% NaCl aqueous solution) of Cyclocarya paliurus polysaccharide (CPP-3) was characterized by different methods such as fourier transform infrared spectra (FT-IR), UV-vis, gas chromatography-mass spectrometry (GC-MS), high performance gel chromatography (HPGLC) and scanning electron microscopy (SEM). Cell viability was measured by MTT test, phagocytosis assay was measured by Neutral red uptake assay, nitrite was measured by Griess assay, TNF-α and IL-1β analysis were measured by ELISA, PGE2 was measured by enzyme immunoassay system. The results showed that CPP-3 was comprised of two polysaccharides with average molecular weight (Mw) of 5.69×104Da and 4.94×103Da. CPP-3 contains six monosaccharides, of which are rhamnose (Rha), arabinose (Ara), xylose (Xyl), mannose (Man), glucose (Glu), galactose (Gal), the molar ratio of six monosaccharides is 0.060:0.109:0.053:0.128:0.293:0.357. CPP-3 increased the amount of NO released from mouse macrophage RAW264.7 and significantly increased the levels of TNF-α, IL-1β and PGE2 (P<0.01). CPP-3 suppressed LPS-stimulated RAW264.7 macrophage to release NO, TNF-α, IL-1β and PGE2 (P<0.01). CPP-3 and LPS accounted for synergistic effect on the release of NO and TNF-α, CPP-3 and LPS accounted for antagonistic effect on the release of IL-1β and PGE2.

The anti-apoptotic effect of fluid mechanics preconditioning by cells membrane and mitochondria in rats brain microvascular endothelial cells

Exercise preconditioning is a simple and effective way to prevent ischemia. This paper further provided the mechanism in hemodynamic aspects at the cellular level. To study the anti-apoptotic effects of fluid mechanics preconditioning, Cultured rats brain microvascular endothelial cells were given fluid intervention in a parallel plate flow chamber before oxygen glucose deprivation. It showed that fluid mechanics preconditioning could inhibit the apoptosis of endothelial cells, and this process might be mediated by the shear stress activation of Tie-2 on cells membrane surface and Bcl-2 on the mitochondria surface.