Investigation on activation in RAW264.7 macrophage cells and protection in cyclophosphamide-treated mice of Pseudostellaria heterophylla protein hydrolysate

Immunomodulatory activity and molecular mechanisms of action of peptides derived from casein hydrolysate by alcalase and flavourzyme based on virtual screening

This study aimed to screen novel immunomodulatory peptides from casein hydrolysates (CH) using alcalase and flavorzyme by virtual screening, and their molecular mechanism were further studied. Based on the primary structural characteristics of immunomodulatory peptides, along with their hydrophobicity and isoelectric point, 3 novel immunomodulatory peptides (ALPMHIR, AMKPWIQPK, NPWDQVKR) were quickly found using virtual screening. These peptides exhibited strong interactions with TLR2/TLR4 through hydrogen bonding and hydrophobic interactions. Molecular docking verified that the key binding sites, such as Ile733, Ala732, and Phe774 in TLR2/TLR4 contributed to docking. Interestingly, the peptide AMKPWIQPK exhibited the strongest immunomodulatory activity and anti-inflammatory activity as 2-way immunomodulatory peptides. Based on western blot analysis and validation using specific inhibitors against MAPK/NF-κB signaling pathways, the results demonstrated that AMKPWIQPK could recognize the TLR2 and TLR4 receptor of the macrophages to upregulate the phospho-IκBα, phospho-p38, and phospho-p65, and further activated the MAPKs/NF-κB signaling pathways to enhance the immunomodulatory activity. These results confirmed that screening and optimizing immunomodulatory peptides by virtual screening and molecular docking were a novel and rapidly feasible method. The peptide AMKPWIQPK was expected to be used as natural-derived immunomodulatory active ingredients in nutritional health care and functional foods.

Traditional uses, phytochemical constituents, pharmacological properties, and quality control of Pseudostellaria heterophylla (Miq.) Pax

ETHNOPHARMACOLOGIC RELEVANCE

Pseudostellaria heterophylla (Miq.) Pax belongs to the Caryophyllaceae family, which is widely used in traditional Chinese medicine in Asia. P. heterophylla was first documented in the classical text Bencao Congxin, also known as "Haier Shen". As a renowned folk medicine with a long history of medicinal application in China, this plant is frequently employed to address spleen deficiency and fatigue, loss of appetite, and weakness after illness. In recent years, P. heterophylla has gained significant global attention as an important medicinal plant, attributable to its pharmacological activities on the immune and endocrine systems, as well as its diverse applications.

AIM OF THE WORK

This review aims to deliver a comprehensive and analytical overview of the ethnopharmacology, phytochemistry, pharmacology, pharmacokinetics, toxicology, and quality control of P. heterophylla, while also offering novel insights and opportunities for future research.

MATERIALS AND METHODS

Relevant information regarding P. heterophylla was gathered from various databases, including Web of Science, PubMed, ACS Publications, Google Scholar, Baidu Scholar, and CNKI, in addition to The Catalogue of Life, the Flora of China database, and The World Flora Online. All published articles in multiple languages have been included and properly cited. The chemical structure of the compound was illustrated utilizing ChemDraw 19.0 software.

RESULTS

P. heterophylla has been traditionally employed to address a range of ailments, including cancer, cardiovascular diseases, diabetes, and respiratory disorders. More than 289 active constituents have been identified in P. heterophylla, comprising cyclic peptides, polysaccharides, saponins, alkaloids, flavonoids, nucleosides, and amino acids. Pharmacological investigations have demonstrated that P. heterophylla and its active constituents exhibit a broad spectrum of biological activities, including anti-cancer, immunomodulatory, antioxidant, hypoglycemic, anti-inflammatory effects, modulation of intestinal flora, enhancement of cognitive function, and inhibition of tyrosine kinase activity. Furthermore, it is extensively utilized in the functional food and cosmetics industries.

CONCLUSION

As a dual-purpose resource for both food and medicine, P. heterophylla possesses significant health care functions and considerable edible and medicinal value, with promising prospects for future development and utilization. However, numerous investigations into the biological activities of P. heterophylla are primarily focused on its extracts and bioactive constituents, and the mechanisms underlying the actions of these extracts and components remain unclear, with a dearth of studies on clinical efficacy and safety. Consequently, further detailed in vitro and in vivo studies investigating the mechanisms of action of pure active compounds of P. heterophylla are warranted, along with additional clinical investigations to ascertain the safety and efficacy of the plant for human use.

Structural characterization and immunomodulatory activity of a polysaccharide from Dioscotea opposita

The purified polysaccharides fraction, DOP-2, was prepared from Dioscorea opposita Thunb (D. opposita). This study combined in vitro and in vivo experiments to comprehensively investigate the index changes in RAW264.7 cells and immunocompromised mice under DOP-2 intervention, aiming to elucidate the potential mechanisms of immunomodulatory effects of DOP-2. DOP-2 (10 ∼ 500 μg/mL) significantly elevated the levels of NO, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) factors secreted by RAW264.7 cells, and restored the body weight of immunosuppressed mice and improve the degree of injury to the immune organ index, resulting in significant immunomodulatory effects. Notably, DOP-2 promoted the production of short-chain fatty acids (SCFAs) in immunosuppressed mice and modulated the composition of their gut microflora. These findings highlight the potential benefits of DOP-2 therapy in improving immune function and gut health, and will provide a theoretical basis for the application of D. opposita polysaccharides as an immunomodulatory adjuvant.

RNA-seq analysis reveals an immunomodulatory peptide from highland barley activating RAW264.7 macrophages via TNF/NF-κB signaling pathway

Highland barley (HB) is an important cereal crop distributed in the plateau region. Bioactive peptides (BAPs) derived from cereal proteins have shown biological functions. However, the knowledge of highland barley peptide (HBP) is limited. This study aims to explore the immunomodulatory activity of HBP and the relationship between immunomodulatory activity and related gene expression through RNA-seq. Firstly, HBP is isolated from protease hydrolysates of HB protein, yielding 12.04% of crude HB protein. The molecular weight of HBP is about 1702 Da analyzed by gel filtration chromatography, and HBP has a specific amino acid sequence as Gln-Pro-Gln-Gln-Pro-Phe-Pro-Gln (QPQPFPQ) analyzed by LC-MS. Besides, HBP contains 42.20% hydrophobic amino acids and 10.86% basic amino acids. Next, the immunomodulatory activity of HBP in vitro shows that HBP enhances the phagocytosis of RAW264.7 macrophages, promotes nitric oxide (NO) production and the mRNA expression of pro-inflammatory genes including tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and inducible nitric oxide synthase (iNOS), and decreases the mRNA expression of anti-inflammatory gene, transforming growth factor β1 (TGF-β1). RNA-seq analysis reveals TNF and nuclear factor kappa B (NF-κB) pathways are upregulated, and RT-qPCR is performed to verify RNA-seq analysis. In conclusion, HBP activates RAW264.7 macrophages via TNF/NF-κB signaling pathway. HBP, as a significant immunomodulatory peptide, might be a promising resource for future functional foods.

Immunomodulatory activity of semen Ziziphi Spinosae protein: a potential plant protein functional food raw material

Semen Ziziphi Spinosae protein (SZSP) is a new plant protein resource with good food functional properties and health care function. However, the biological activity of SZSP has not been further studied, which greatly limits the development and utilization of SZSP in the food industry. The aim of this study was to investigate the protective effect of SZSP on immunosuppressed mice and its inhibitory effect on immune-stimulated RAW264.7 cells. The results demonstrated that SZSP remarkably improved the immunomodulatory secretion in serum (interleukin-2, tumor necrosis factor-α [TNF-α], interferon-γ, immunoglobulin-A, immunoglobulin-G, immunoglobulin-M) and primary macrophages (nitric oxide, interleukin-1β, TNF-α) and promoted the NK-cell killing activity of primary splenocytes in CTX-induced immunosuppression mice. Immunohistochemical analysis results indicated that the secretion of CD₄⁺ and CD₈⁺ in the spleen and thymus can be regulated by SZSP, leading to inhibition of the damage induced by cyclophosphamide in mice. Meanwhile, in order to clarify the immunomodulatory mechanism of SZSP, we showed that SZSP significantly inhibited the secretion of NO, interleukin-6, and TNF-α and reduced the phosphorylation expression of p-ERK, p-JNK, and p-IκBα in lipopolysaccharide-stimulated RAW264.7 cells. Therefore, the immunomodulatory effect of SZSP may be related to the activation of MAPKs and NF-κB signaling pathways. Based on the above studies, the preliminary purification of SZSP was continued, and S1F2G1 with immunomodulatory activity was obtained. Taken together, SZSP has an immunoregulatory effect in vivo and in vitro and may be a favorable candidate of functional food raw material for regulating immune responses.

Biflavonoid quercetin protects against cyclophosphamide-induced organ toxicities via modulation of inflammatory cytokines, brain neurotransmitters, and astrocyte immunoreactivity

BACKGROUND

Cyclophosphamide use has been associated with increased oxidative stress in cells and tissues. Quercetin's antioxidative properties make it of potential benefit in such conditions of oxidative stress.

OBJECTIVE

To assess quercetin's ability to mitigate cyclophosphamide-induced organ toxicities in rats.

METHODS

Sixty rats were assigned into six groups. Groups A and D served as normal and cyclophosphamide control and were fed standard rat chow, groups B and E were fed quercetin supplemented diet (100 mg/kg of feed), while those in groups C and F were fed quercetin at 200 mg/kg of feed. Groups A-C received intraperitoneal (ip) normal saline on days 1 and 2, while D-F received ip cyclophosphamide (150 mg/kg/day on days 1 and 2). On day 21, behavioural tests were carried out, animals were sacrificed and blood samples taken. Organs were processed for histological study.

RESULTS

Quercetin reversed cyclophosphamide-induced decrease in body weight, food intake and total antioxidant capacity, and increase in lipid peroxidation (p = 0.001), It also reversed derangement in levels of liver transaminase, urea, creatinine and proinflammatory cytokines (p = 0.001). Improvement in working-memory and anxiety-related behaviours were also observed. Finally, quercetin reversed alterations in levels of acetylcholine, dopamine and brain-derived neurotropic factor (p = 0.021); while reducing serotonin levels and astrocyte immunoreactivity.

CONCLUSION

Quercetin shows significant ability to protect against cyclophosphamide-induced changes in rats.

Synergistic Antitumor Effect of Grifola frondose Polysaccharide—Protein Complex in Combination with Cyclophosphamide in H22 Tumor-Bearing Mice

Hepatocellular carcinoma (HCC) is the most common type of liver malignancy and remains a global health threat. The objective of the current study was to determine whether the combination of a cold-water extracted polysaccharide-protein complex from Grifolia frondosa (GFG) and cyclophosphamide (CTX) could inhibit tumor growth by suppressing the expression of angiogenesis-related proteins in H22 tumor-bearing mice. The results showed that the inhibition rate of GFG combined with CTX on H22 tumors was 65.29%, which was significantly higher than that of GFG treatment alone (24.82%). GFG combined with CTX significantly increased the expression levels of vascular endothelial growth factor, basic fibroblast growth factor, matrix metalloproteinase 2, and matrix metalloproteinase 9. Additionally, thymus index, spleen index, natural killer (NK) cell activity, interferon-γ (IFN-γ), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2) levels increased significantly after GFG treatment, especially after high-doses of GFG combined with CTX treatment (p < 0.05). The thymus index, spleen index, NK cell activity, IFN-γ, IL-1β, TNF-α, and IL-2 levels were 1.90, 1.46, 1.30, 2.13, 1.64, 2.03, and 1.24 times of those treated with CTX alone. Thus, we proposed that GFG can alleviate the side effects of CTX by relieving the immunosuppressive effect, liver/renal injury, and oxidative stress. In conclusion, the combination of GFG and CTX for cancer treatment may be a promising strategy, and GFG is expected to be a potential adjuvant alternative for the treatment of HCC.

Chemical Characterization and Immunomodulatory Activity of Fucoidan from Sargassum hemiphyllum

Fucoidan is a sulfated algal polyanionic polysaccharide that possesses many biological activities. In this paper, a fucoidan (SHF) polysaccharide was extracted from Sargassum hemiphyllum collected in the South China Sea. The SHF, with a molecular weight of 1166.48 kDa (44.06%, w/w), consisted of glucose (32.68%, w/w), galactose (24.81%, w/w), fucose (20.75%, w/w), xylose (6.98%, w/w), mannose (2.76%, w/w), other neutral monosaccharides, and three uronic acids, including glucuronic acid (5.39%, w/w), mannuronic acid (1.76%, w/w), and guronuronic acid (1.76%, w/w). The SHF exhibited excellent immunostimulatory activity. An immunostimulating assay showed that SHF could significantly increase NO secretion in macrophage RAW 264.7 cells via upregulation of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) levels based on both gene expression and protein abundance. These results suggest that SHF isolated from Sargassum hemiphyllum has great potential to act as a health-boosting ingredient in the pharmaceutical and functional-food fields.

In vitro immunomodulatory and antioxidant effects of oligopeptides and four characteristic peptides in black-bone silky fowl (Gallus gallus domesticus Brisson)

Black-bone silky fowl (Gallus gallus domesticus Brisson) is considered to have strengthening effect on the body and immunomodulatory effects. The black-bone silky fowl peptide (BSFP) was produced by enzymatic digestion of the whole black-bone silky fowl (including the head and claws) after removal of the viscera. Afterwards, the four of the characteristic peptides Glu-Phe (EF), Glu-Glu-Leu (EEL), Glu-His-Pro-Thr (EHPT), Ala-Gly-Gly-His (AGGF) of the BSFP were identified by HPLC-MS/MS. The preventive effects of BSFP and the four characteristic peptides on antioxidant and immunomodulation were investigated. The antioxidant capacity was assessed by in vitro HepG2 intracellular reactive oxygen species (ROS). The immunomodulatory experiments were conducted by measuring the effects of the BSFP and four peptides on the proliferation of splenocytes, T and B lymphocytes cells, the CD4⁺ /CD8⁺ T lymphocytes ratio, and the phagocytic capacity of macrophages and the nitric oxide (NO) content of macrophages. The four peptides of BSFP showed strong antioxidant capacity, with the most potent peptide for intracellular ROS being AGGF, with 56% inhibition. AGGF, EF, and BSFP showed highly positive effects on splenocyte proliferation and when Concanavalin A (ConA) was used as a stimulus for T lymphocytes and lipopolysaccharide (LPS) as a stimulus for B lymphocytes, the peptides stimulated cell proliferation in a dose-dependent manner. Of these, EF, AGGF, and BSFP promoted the proliferation of T lymphocytes; EF, EHPT, and BSFP significantly promoted the proliferation of B lymphocytes. EHPT and BSFP increased the CD4⁺ /CD8⁺ ratio of T cells. Needle aspiration of neutral red was significantly promoted by macrophages treated with peptides other than EF. In addition, EEL, EHPT, AGGF, and BSFP had a promotive effect on NO production in phagocytes. The results indicate that BSFP is a peptide product with good immunomodulatory functions, four peptides identified from BSFP show outstanding effects in terms of antioxidant properties and immunomodulation. PRACTICAL APPLICATIONS: In this study, the amino acid composition and relative molecular masses of the black-bone silky fowl peptide were analyzed, while the four peptides with significant effects on antioxidant and immunomodulatory properties in black-bone silky fowl peptide were identified by HPLC-MS/MS technique. Positive effects of black-bone silky fowl peptide and its four peptides on antioxidant capacity and immunomodulatory ability as revealed by cell experiments. The results of this experiment provide a preliminary theoretical basis for the development of new functional foods using black-bone silky fowl peptide and their characteristic peptides.

The immune-enhancing effect and in vitro antioxidant ability of different fractions separated from Colla corii asini

In this study, Colla corii asini (CCA) was fractionated into three fractions with different molecular weights using ultracentrifugation equipment. Components with a molecular weight of >10 kDa in F1 accounted for 81.90%, whereas that in F2 and F3 was 15.63% and 0.94%, respectively. The immunomodulatory activity of CCA fractions was investigated using RAW264.7 cell model and their antioxidant abilities were evaluated by 2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) and ferric-reducing antioxidant power (FRAP) assay. The results indicated that RAW264.7 cells treated with F1 released the highest level of nitric oxide, reactive oxygen species, interleukin-6, and tumor necrosis factor-α. The ABTS and FRAP value of F1 were 65.81% and 29.33 μM TE/L, respectively, which were 22.53%, 128.44% and 43.72%, 132.16% higher than that of F2 and F3, respectively. These results suggested that components with a molecular weight of >10 kDa in CCA had stronger immunomodulatory and antioxidant ability, which would help develop the health food based on CCA. PRACTICAL APPLICATIONS: Colla corii asini (CCA) is a famous protein-based traditional Chinese medicine and nutritional supplement. During the processing of CCA, the molecular weight (MW) of CCA collagen components changed dynamically due to the protein aggregation, degradation, and the Maillard reaction. Some studies have shown that the MW distribution of CCA was not uniform. However, the MW range of CCA components which has strong antioxidant and immunomodulatory activity is still not clear, and few studies have reported the mechanism of CCA's immunomodulatory activity and active ingredients. Therefore, it is important to figure out the characteristics of CCA components with stronger immunomodulatory and antioxidant ability, such as the MW distribution and chemical composition of CCA fractions. And this study will be great for the processing of CCA products which has better biological functions.

Immunomodulatory Effects of Chicken Broth and Histidine Dipeptides on the Cyclophosphamide-Induced Immunosuppression Mouse Model

The carnosine and anserine, which represent histidine dipeptides (HD), are abundant in chicken broth (CB). HD are endogenous dipeptide that has excellent antioxidant and immunomodulatory effects. The immunomodulatory effect of CB hydrolysate (CBH) and HD in cyclophosphamide (CTX)-induced immunosuppressed mice was examined in this study. CBH and HD were given to mice via oral gavage for 15 days, accompanied by intraperitoneal CTX administration to induce immunosuppression. CBH and HD treatment were observed to reduce immune organ atrophy (p < 0.05) and stimulate the proliferation of splenic lymphocytes (p < 0.05) while improving white blood cell, immunoglobulin M (IgM), IgG, and IgA levels (p < 0.05). Moreover, CBH and HD strongly stimulated interleukin-2 (IL-2) and interferon-gamma (IFN-γ) production by up-regulating IL-2 and IFN-γ mRNA expression (p < 0.05) while inhibiting interleukin-10 (IL-10) overproduction and IL-10 mRNA expression (p < 0.05). In addition, CBH and HD prevented the inhibition of the nitric oxide (NP)/cyclic guanosine monophosphate-cyclic adenosine monophosphate (cGMP-cAMP)/protein kinase A (PKA) signaling pathway (p < 0.05). These results indicate that CBH and HD have the potential to prevent immunosuppression induced by CTX. Our data demonstrate that CBH can effectively improve the immune capacity of immunosuppressed mice similar to the same amount of purified HD, which indicates that CBH plays its role through its own HD.

Immunoenhancing Effects of Cyclina sinensis Pentadecapeptide through Modulation of Signaling Pathways in Mice with Cyclophosphamide-Induced Immunosuppression

Our study aimed to investigate the immune-enhancing mechanism of the pentadecapeptide (RVAPEEHPVEGRYLV) from Cyclina sinensis (SCSP) in a cyclophosphamide (CTX)-induced murine model of immunosuppression. Our results showed that SCSP treatment significantly increased mouse body weight, immune organ indices, and the production of serum IL-6, IL-1β, and tumor necrosis factor (TNF)-α in CTX-treated mice. In addition, SCSP treatment enhanced the proliferation of splenic lymphocytes and peritoneal macrophages, as well as phagocytosis of the latter in a dose-dependent manner. Moreover, SCSP elevated the phosphorylation levels of p38, ERK, JNK, PI3K and Akt, and up-regulated IKKα, IKKβ, p50 NF-κB and p65 NF-κB protein levels, while down-regulating IκBα protein levels. Our results indicate that SCSP has immune-enhancing activities, and that it can activate the MAPK/NF-κB and PI3K/Akt pathways to enhance immunity in CTX-induced immunosuppressed mice.

The immune-enhancing effects of a mixture of Astragalus membranaceus (Fisch.) Bunge, Angelica gigas Nakai, and Trichosanthes Kirilowii (Maxim.) or its active constituent nodakenin

ETHNOPHARMACOLOGICAL RELEVANCE

A mixture (SH003) of Astragalus membranaceus (Fisch.) Bunge, Angelica gigas Nakai, and Trichosanthes Kirilowii (Maxim.) has beneficial effects against several carcinomas. There have been few reports on an immune-enhancing activity of SH003 and its active constituent nodakenin.

AIM OF THE STUDY

This study aimed at identifying the immune-enhancing effect of SH003 and nodakenin.

MATERIALS AND METHODS

The immune-enhancing effect was evaluated using RAW264.7 macrophages, mouse primary splenocytes, and a cyclophosphamide (CP)-induced immunosuppression murine model.

RESULTS

The results show that SH003 or nodakenin stimulated the production levels of granulocyte colony-stimulating factor, IL-12, IL-2, IL-6, TNF-α, and nitric oxide (NO) and the expression levels of iNOS in RAW264.7 macrophages. SH003 or nodakenin also enhanced NF-κB p65 activation in RAW264.7 macrophages. SH003 or nodakenin stimulated the production levels of IFN-γ, IL-12, IL-2, TNF-α, and NO and the expression levels of iNOS in splenocytes. SH003 or nodakenin increased the splenic lymphocyte proliferation and splenic NK cell activity. In addition, SH003 or nodakenin increased the levels of IFN-γ, IL-12, IL-2, IL-6, and TNF-α in the serum and spleen of CP-treated mice, alleviating CP-induced immunosuppression.

CONCLUSION

Taken together, the results of this study show that SH003 improved immunosuppression through the activation of macrophages, splenocytes, and NK cells. These findings suggest that SH003 could be applied as a potential immunostimulatory agent for a variety of diseases caused or exacerbated by immunodeficiency.

Immunomodulatory activity of egg yolk protein hydrolysates prepared by novel two-step hydrolysis: A study of mechanism and stability after in vitro digestion model

The aim of this study was to determine the immunomodulatory activity of 2-step egg yolk protein hydrolysates. A two-step hydrolysate of egg yolk protein was prepared using 2 enzymes sequentially, pancreatin and neutrase (EYPH-PN). Our results illustrated that EYPH-PN increased the expression of inducible nitric oxide synthase (iNOS) mRNA in macrophages, resulting in increased nitric oxide (NO) production. EYPH-PN could also enhance the production of tumor necrosis factor (TNF)-α and interleukin (IL)-6 at both the mRNA and protein levels in macrophages. In addition, treatment with EYPH-PN increased the phagocytic activity of macrophages. According to the evaluation with specific inhibitors, both p38 and JNK cell signaling pathways were involved in the activation of macrophages induced by EYPH-PN. As the TLR-2 receptor of macrophages was blocked, the NO production induced by EYPH-PN was decreased. These results suggest that EYPH-PN activates RAW 264.7 macrophages via the TLR-2/p38/JNK pathway to increase the production of NO, TNF-α, and IL-6, and increases phagocytic activity. Furthermore, the immunomodulatory activity of EYPH-PN was maintained even after applying the in vitro digestion model. Taken together, EYPH-PN could be used as a functional food ingredient with excellent immunomodulatory activity in the food industry. Therefore, this study suggests a new alternative method to effectively utilize egg yolk protein, a by-product of the poultry industry.

SBT (Composed of Panax ginseng and Aconitum carmichaeli) and Stigmasterol Enhances Nitric Oxide Production and Exerts Curative Properties as a Potential Anti-Oxidant and Immunity-Enhancing Agent

Immune dysregulation is a risk factor for several diseases, including infectious diseases. Immunostimulatory agents have been used for the treatment of immune dysregulation, but deleterious adverse effects have been reported. The present study aims to establish the anti-oxidant and immunity-enhancing effects of Sambu-Tang (SBT), composed of Panax ginseng and Aconitum carmichaeli, and stigmasterol (Stig), an active compound of SBT. Immune-related factors were analyzed in RAW264.7 macrophage cells, mouse primary splenocytes, and the serum and spleen of cyclophosphamide-induced immunosuppressed mice. Results showed that the production levels of nitric oxide (NO) and expression levels of inducible NO synthase and heme oxygenase-1 were increased following SBT or Stig treatment in RAW264.7 cells. SBT or Stig increased the production levels of G-CSF, IFN-γ, IL-12, IL-2, IL-6, and TNF-α and induced the activation of NF-κB in RAW264.7 cells. SBT or Stig promoted splenic lymphocyte proliferation and increased splenic NK cell cytotoxic activity. In addition, SBT or Stig enhanced the levels of IFN-γ, IL-12, IL-2, IL-6, or TNF-α in the serum and spleen of the immunosuppressed mice. SBT or Stig increased the superoxide dismutase activity in the spleen. Collectively, SBT and Stig possess anti-oxidant and immunomodulatory activities, so they may be considered effective natural compounds for the treatment of various symptoms caused by immune dysregulation.

Immune-enhancing effects of β-lactoglobulin glycated with lactose following in vitro digestion on cyclophosphamide-induced immunosuppressed mice

β-Lactoglobulin (β-LG) is a major milk protein, making up more than 53% of the total whey proteins, and is seen as a valuable ingredient in food processing because of its high essential amino acid content and diverse functional applications. The Maillard reaction can occur during the storage and processing of food and generate various beneficial effects, including anti-allergenicity, antioxidant, and immunomodulatory effects. The addition of an β-LG-lactose conjugate (LGL) produced by the Maillard reaction was shown to have a strong immune-enhancing effect, increasing both nitric oxide generation and cytokine expression through activation of RAW 264.7 cells, even after in vitro digestion. Furthermore, daily LGL administration resulted in the upregulation of several immune markers in a cyclophosphamide-induced immunosuppressive mouse model, indicating that this treatment stimulates multiple immune cells, including macrophages, natural killer cells, and lymphocytes, enhancing the proliferation and activation of both the innate and adaptive immune responses. Taken together, these findings indicate that consuming LGL on a regular basis can improve immunity by increasing the natural production of various immune cells.

Anti-inflammatory and Antioxidant Activity of Peptides From Ethanol-Soluble Hydrolysates of Sturgeon (Acipenser schrenckii) Cartilage

Research has shown that cartilage containing chondroitin sulfate and protein presents versatile bioactivities. Chondroitin sulfate in cartilage is beneficial to activate the immune system while the protein/peptide has not been fully understood. The current study investigated the antioxidant and anti-inflammatory properties of ethanol-soluble hydrolysates of sturgeon cartilage (ESCH) prepared through hot-pressure, enzymatic hydrolysis and ethanol extraction. UV spectrum, IR and agarose gel electrophoresis results suggested the successful exclusion of chondroitin sulfate from peptides. Nitric oxide (NO) floods in cells activated by inflammation. It was inhibited when administrated with ESCH. To further explain the observed anti-inflammatory activity, ESCH was separated with Sephadex G-15 into 3 components, among which F3 showed a higher NO inhibition rate and significantly reduced the production of the proinflammatory cytokine IL-6. In addition, the yield of IL-10 increased. Western blotting suggested that F3 downregulated the NO content and IL-6 level by suppressing Mitogen-activated protein kinases (MAPK) channels. Moreover, both ESCH and F3 showed DPPH and ABTS free radical scavenging abilities which was possibly related to the anti-inflammatory property. These results indicated that ESCH behaved anti-inflammatory and antioxidant activities. Cartilage may be a good source to produce anti-inflammatory peptides.

Cyclophosphamide induced physiological and biochemical changes in mice with an emphasis on sensitivity analysis

The widespread use of cyclophosphamide (CP) in medical treatment had caused ubiquitous contamination in the environment. To data, many studies have been carried out on the toxic effect of CP. However, among these toxic effects of CP, which are the most sensitive remains unclear. Present study aimed to investigate the toxicity of CP on mice and evaluate the sensitivity of physiological-biochemical parameters upon exposure of mice to CP. Results showed that as compared with the control group, CP caused significant reduction in body weight (p < 0.01), spleen coefficient (p < 0.01), leukocyte density (p < 0.01) and alanine transaminase (ALT) in kidney (p < 0.01); However superoxide dismutase (SOD), malondialdehyde (MDA), ALT in liver and creatinine (Cr) in kidney significantly (p < 0.05) increased. Among the suppressed physiological and biochemical parameters, the sensitivity to CP toxicity was generally ranked as body weight > leukocyte density > ALT in kidney > spleen coefficient; while among the stimulated parameters, the sensitivity was ranked as MDA (liver) > Cr (kidney) > ALT (liver). Overall, the most sensitive parameters to CP toxicity may be associated with growth, immune system and the normal function of liver and kidney.

Radix Pseudostellariae protein-curcumin nanocomplex: Improvement on the stability, cellular uptake and antioxidant activity of curcumin

Radix Pseudostellariae protein (RPP) with satisfactory antioxidant activity and self-assembled ability was extracted from dried Radix Pseudostellariae. In this study, RPP-curcumin nanocomplex (RPP-Cur) was fabricated, and its improvement on the stability, cellular uptake and antioxidant activity of curcumin was investigated. RPP-Cur with homogeneously spherical structure exhibited good stability, which could maintain the morphology against simulated gastrointestinal digestion and up to 300 mM ionic concentration. After RPP nanoparticles encapsulation, the retention of curcumin increased 1.45 times under UV irradiation for 6 h. Besides, RPP-Cur exhibited additive reducing power of curcumin and RPP. The transport efficiency of hydrophobic curcumin across Caco-2 cells monolayer was greatly improved by RPP nanoparticle by 3.7 folds. RPP-Cur was able to be internalized by Caco-2 cells dose-dependently via macropinocytosis and clathrin-mediated endocytosis. The cellular uptake efficiency of embedded curcumin in RPP nanoparticles by Caco-2 cells was significantly higher than that of free curcumin, which might contribute to the enhanced intracellular antioxidant activity of RPP-Cur. These findings suggest that the proteins from Radix Pseudostellariae have potential to be developed into novel delivery system with intrinsic antioxidant activity for the hydrophobic active molecules in healthy food field.

Isolation, Identification, and Immunomodulatory Effect of a Peptide from Pseudostellaria heterophylla Protein Hydrolysate

In this study, a bioactive peptide YGPSSYGYG (YG-9) with immunomodulatory activity was isolated and identified from Pseudostellaria heterophylla protein hydrolysate. The highest proliferation index of mouse spleen lymphocytes reached 1.19 in the presence of 50 μg/mL YG-9. YG-9 could activate RAW264.7 cells by promoting the secretions of NO, the pinocytosis activity, and the productions of ROS and TNF-α. Moreover, YG-9 enhanced the expressions of TLR2 and TLR4 in RAW264.7 cells. TNF-α secretions induced by YG-9 were reduced in TLR2 and TLR4 siRNAs knockdown cells, and this suggested that macrophage activation of YG-9 was through TLR2 and TLR4. Furthermore, YG-9 promoted the translocation of NF-κB through the acceleration of IκB-α phosphorylation and degradation. Also, TNF-α secretions promoted by YG-9 were inhibited by NF-κB-specific inhibitors pyrrolidine dithiocarbamate and BAY11-7082. Altogether, these results suggested YG-9 activated RAW264.7 cells via the TLRs/NF-κB/TNF-α signaling pathway.

Mesenchymal Stem Cells Enhance Pulmonary Antimicrobial Immunity and Prevent Following Bacterial Infection

Background

Immunosuppressants such as cyclophosphamide (CTX) have been employed to treat a wide array of autoimmune diseases. The most unfavourable side effects of these drugs are their suppression on the antimicrobial immunity and increasing the risk of infection. As a promising substitution/adjunct, mesenchymal stem cells (MSCs) are currently being tested in several clinical trials. However, their influence on the recipients' antimicrobial immunity remains unclear.

Methods

In this study, C57BL/6 mice were treated with either CTX or MSCs, and then both the innate and adaptive immunity of the lung were determined. To investigate the influence of CTX and MSCs on the immune defence against infection, the treated mice were intranasally infected with opportunistic pathogen Haemophilus influenzae (Hi). Bacterial clearance and antibacterial immune responses were analysed.

Results

Our data showed that CTX strongly inhibited the proliferation of lung immune cells, including alveolar macrophages (AMs) and T cells, whereas MSCs increased the numbers of these cells. CTX suppressed the phagocytic activity of AMs; on the contrary, MSCs enhanced it. Notably, infusion of MSCs led to a remarkable increase of regulatory T cells and Th1 cells in the lung. When infected by Hi, CTX did not significantly impair the elimination of invaded bacteria. However, MSC-treated mice exhibited accelerated bacterial clearance and moderate inflammation and tissue damage.

Conclusion

Our study reported that unlike traditional immunosuppressants, modulation of MSCs on the recipient's immune response is more elegant. It could preserve and even enhance the antimicrobial defence, suggesting that MSCs are better choice for patients with high risk of infection or those who need long-term immunosuppressive regimen.

Effects of gelatin-based antifreeze peptides on cell viability and oxidant stress of Streptococcus thermophilus during cold stage

Cold stage adversely affects cell proliferation and cell viability of probiotics such as Streptococcus thermophilus in food industry, new type of cryoprotectants continues to be needed. Gelatin-based antifreeze peptide becomes a popular topic because of its cryoprotective effects on cold-stressed probiotics. In this study the effects of tilapia scales antifreeze peptides (TSAPP) on cell viability and oxidant stress of S. thermophilus during cold stage were investigated. The results showed that the percentage of viable cells was increased 10.85 folds compared with control groups. Addition of TSAPP activated the activities of ATPases, relieved the hyperpolarization of cell membrane potential and regulated the intracellular Ca2+ concentration. Furthermore, TSAPP significantly inhibited reactive oxygen species level and malonaldehyde content in cells. Under cryopreservation with TSAPP, cells of S. thermophilus maintained higher activities of antioxidant enzymes including catalase, peroxidase and total antioxidant capacity. These findings indicate that TSAPP likely offered its cellular protection by maintaining membrane integrity and alleviation of oxidative stress.