Immune activation of murine RAW264.7 macrophages by sonicated and alkalized paramylon from Euglena gracilis

Identification of intracellular activation mechanism of rhamnogalacturonan-I type polysaccharide purified from Panax ginseng leaves in macrophages and roles of component sugar chains on activity

This study aimed to investigate the mechanisms underlying intracellular signaling pathways in macrophages in relation to the structural features of rhamnogalacturonan (RG) I-type polysaccharide (PGEP-I) purified from Panax ginseng leaves. For this investigation, we used several specific inhibitors and antibodies against mitogen-activated protein kinase (MAPK), nuclear factor-kappa B (NF-κB), and pattern recognition receptors (PRRs). Furthermore, we investigated the roles of component sugar chains on immunostimulating activity through a sequential enzymatic and chemical degradation steps. We found that PGEP-I effectively induced the phosphorylation of several MAPK- and NF-κB-related proteins, such as p38, cJun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p65. Particularly, immunocytochemistry analysis confirmed the PGEP-I-induced translocation of p65 into the nucleus. Furthermore, the breakdown of PGEP-I side chains and main chain during sequential enzymatic and chemical degradation reduced the PGEP-I-induced macrophage cytokine secretion activity. IL-6, TNF-α, and NO secreted by macrophages are associated with several signaling pathway proteins such as ERK, JNK, and NF-κB and several PRRs such as dectin-1, CD11b, CD14, TLR2, TLR4, and SR. Thus, these findings suggest that PGEP-I exerts potent macrophage-activating effects, which can be attributed to its typical RG-I structure comprising arabinan, type II arabinogalactan, and rhamnose-galacturonic acid repeating units in the main chain.

In vitro and in vivo immuno-enhancing effect of fucoidan isolated from non-edible brown seaweed Sargassum thunbergii

Fucoidan has been reported to have various biological activities, such as antioxidant, antitumor and anticoagulant, with various health benefits. However, few studies have been conducted to extract fucoidan from Sargassum thunbergii in terms of its immuno-enhancing activities. This aim of this study was to investigate the immuno-enhancing effect of fucoidan (S3) isolated from Sargassum thunbergii through water extraction and ethanol precipitation in RAW 264.7 macrophages and zebrafish. The results showed that S3 contained a relatively high content of fucose and sulfated polysaccharide. Fourier-transform infrared spectroscopy (FTIR) results show that the characteristic peaks at 845 cm-1 and 1220-1270 cm-1 indicate that S3 contains sulfate groups. In vitro, S3 effectively enhanced nitric oxide (NO) production and phagocytic activity. In addition, the results of the study demonstrated that the secretion of tumor necrosis factor-α, interleukin (IL)-6, IL-1β, and IL-10 was upregulated by nuclear factor kappa B (NF-κB) signaling pathway in a dose-dependent manner. In vivo, S3 activates zebrafish immune responses by promoting secretion of NO and activating the NF-κB pathway. Overall, these results suggest that S3 could be used as a functional ingredient added to nutritional supplements and functional foods.

Euglena gracilis (Euglena) powder supplementation enhanced immune function through natural killer cell activity in apparently healthy participants: A randomized, double-blind, placebo-controlled trial

Euglena gracilis (Euglena) is a microalgae found in most freshwater environments that produces paramylon, an insoluble β-1,3-glucan linked to human immunity. We hypothesized that Euglena powder has effects on immune function in apparently healthy adults. The study included male or female volunteers between the ages of 20 and 70 years who had white blood cell counts ranging from 4 × 103/µL to 10 × 103/µL, a "severe" rating on the stress questionnaire from the Korea National Health and Nutrition Examination Survey, and at least 2 upper respiratory infections with cold-like symptoms in the previous year. Participants received either a placebo or 700 mg of Euglena powder daily for 8 weeks. The study measured natural killer cell activity, cytokine concentrations, and blood lipid profiles to confirm the immune effect of Euglena consumption. In conclusion, Euglena improved immunological function through natural killer cell activity. Safety assessment showed no significant changes in vital signs or clinical chemistry indicators, and there were no adverse events associated with Euglena consumption. Euglena supplementation may help boost the immune systems of healthy individuals.

β-Glucans in particulate and solubilized forms elicit varied immunomodulatory and apoptosis effects in teleost macrophages in a dosedependent manner

β-Glucans are a group of heterogeneous glucose polymers that possess immunomodulatory activities. The complex nature of their structures, uncertainty regarding the doses, and variable immune effects pose a challenge to comprehensive understanding. In this study, we investigated the immune responses and apoptosis effects in Nile tilapia (Oreochromis niloticus) head kidney macrophages (MФ) upon exposure to two β-Glucans (Paramylon and Laminarin) at low and high doses. Our results demonstrate that Paramylon elicits more robust immune responses than Laminarin, albeit with a dose-limiting effect. We also observed that the high-dose Paramylon induces apoptosis, whereas no such effect was detected in Laminarin treatment. Mechanistically, high-dose Paramylon activates the intrinsic apoptosis pathway, with significantly up-regulation of intrinsic apoptosis-related genes and impaired mitochondrial function. On the other hand, Laminarin triggers metabolic reprogramming in MФ, resulting in the enrichment of the metabolite α-Ketoglutarate, which protects the MФ from apoptosis. Overall, our findings highlight the importance of identifying the optimal dose range for β-Glucans, based on sources or structures, to achieve maximal immunomodulatory effects. These results have important implications for the design and optimization of β-Glucans-based drugs or adjuvants in immunotherapies.

Anti-inflammatory Effect of a Combination of Cannabidiol and Morinda citrifolia Extract on Lipopolysaccharide-stimulated RAW264 Macrophages

BACKGROUND/AIM

The inflammatory response plays an important role in the activation and progression of many inflammation-related diseases. Cannabis sativa and Morinda citrifolia have long been used in folk medicine to treat inflammation. Cannabidiol is the most abundant non-psychoactive phytocannabinoid in C. sativa and exhibits anti-inflammatory activity. The objective of this study was to examine the anti-inflammatory effect of cannabidiol in combination with M. citrifolia and compare its effects with those of cannabidiol alone.

MATERIALS AND METHODS

RAW264 cells stimulated with lipopolysaccharide (200 ng/ml) were treated with cannabidiol (0-10 μM), M. citrifolia seed extract (0-100 μg/ml), or a combination of both for 8 or 24 h. Following the treatments, nitric oxide production in the activated RAW264 cells and the expression of inducible nitric oxide synthase were assessed.

RESULTS

Our results showed that combination of cannabidiol (2.5 μM) and M. citrifolia seed extract (100 μg/ml) exhibited more efficient inhibition of nitric oxide production than cannabidiol treatment alone in lipopolysaccharide-stimulated RAW264 cells. The combination treatment also reduced the expression of inducible nitric oxide synthase.

CONCLUSION

These results suggest that the anti-inflammatory effect of combined treatment with cannabidiol and M. citrifolia seed extract causes a reduction in the expression of inflammatory mediators.

Dectin-1 reactivity to paramylon derived from Euglena gracilis EOD-1

Euglena gracilis is a microalga that has recently attracted attention because of its bioactivities. Paramylon (PM), a major β-1,3-glucan, constitutes 70%-80% of the cells of the E. gracilis EOD-1 strain. Dectin-1 is a pattern recognition receptor that recognizes β-glucan. However, it is unclear whether PM binds to dectin-1. In this study, we investigated the reactivity of EOD1PM with dectin-1 by analyzing the binding of soluble murine and human dectin-1-Fc fusion protein (m dectin-1 Fc, h dectin-1 Fc) to EOD1PM using flow cytometry and ELISA.m dectin-1 Fc bound to EOD1PM particles when m dectin-1-Fc is added. Furthermore, the binding specificity was examined in a competitive reaction following addition of a soluble antigen. It was found that the binding of m dectin-1-Fc to EOD1PM was not inhibited by the addition of dextran or ovalbumin but by the addition of solubilized EOD1PM or Candida cell wall- solubilized β-glucan. In addition, the h dectin-1-Fc fusion protein was found to specifically bind to EOD1PM. These results suggest that dectin-1 recognizes and binds to the β-glucan structure of EOD1PM.Dectin-1 is expressed in leukocytes as a β-glucan receptor and is involved in the expression of various biological activities; therefore, the dectin-1 pathway may be involved in the biological activity of EOD1PM.

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.

Immunoenhancing Effects of Euglena gracilis on a Cyclophosphamide-Induced Immunosuppressive Mouse Model

In this study, the effects of the immune stimulator Euglena gracilis (Euglena) in cyclophosphamide (CCP)-induced immunocompromised mice were assessed. The key component β-1,3-glucan (paramylon) constitutes 50% of E. gracilis. Mice were orally administered Euglena powder (250 and 500 mg/kg body weight (B.W.)) or β-glucan powder (250 mg/kg B.W.) for 19 days. In a preliminary immunology experiment, ICR mice were intraperitoneally injected with 80 mg of CCP/kg B.W. during the final 3 consecutive days. In the main experiment, BALB/c mice were treated with CCP for the final 5 days. To evaluate the enhancing effects of Euglena on the immune system, mouse B.W., the spleen index, natural killer (NK) cell activity and mRNA expression in splenocytes lungs and livers were determined. To detect cytokine and receptor expression, splenocytes were treated with 5 μg/ml concanavalin A or 1 μg/ml lipopolysaccharide. The B.W. and spleen index were significantly increased and NK cell activity was slightly enhanced in all the experimental groups compared to the CCP group. In splenocytes, the gene expression levels of tumor necrosis factor-α, interferon-γ, interleukin (IL)-10, IL-6, and IL-12 receptor were increased in the E. gracilis and β-glucan groups compared to the CCP group, but there was no significant difference. Treatment with 500mg of Euglena/kg B.W. significantly upregulated dectin-1 mRNA expression in the lung and liver compared to the CCP group. These results suggest that Euglena may enhance the immune system by strengthening innate immunity through immunosuppression.

Paramylon from Euglena gracilis Prevents Lipopolysaccharide-Induced Acute Liver Injury

Acute liver injury (ALI) is a life-threatening syndrome with high mortality and lacks effective therapies. Rodents under LPS (lipopolysaccharide)/D-Gal (D-galactosamine) stress mimic ALI by presenting dramatically increased inflammation and cell death in the liver. Euglena gracilis, functioning like dietary fiber, is commonly used as a paramylon (Pa)-rich nutritional supplement that has various biological effects such as regulating immune system, anti-obesity, and anti-tumor. Here, we found that Pa or sonicated and alkalized paramylon (SA-Pa) alleviated the LPS/D-Gal-induced hepatic histopathological abnormalities in mice. Compared with Pa, SA-Pa had lower molecular weights/sizes and showed better efficacy in alleviating injury-induced hepatic functions, as well as the transcriptional levels of inflammatory cytokines. Moreover, SA-Pa treatment promoted M2 macrophage activation that enhanced the anti-inflammatory function in the liver, and downregulated STAT3 target genes, such as Fos, Jun, and Socs3 upon the injury. Meanwhile, SA-Pa treatment also alleviated apoptosis and necroptosis caused by the injury. Our results demonstrated that SA-Pa efficiently protected the liver from LPS/D-Gal-induced ALI by alleviating inflammation and cell death.

Fecal extract from obese horses induces an inflammatory response by murine macrophages in vitro

OBJECTIVE

To compare the inflammatory response of murine macrophages exposed to the enteric microbiome of obese horses versus nonobese horses.

SAMPLE

Fecal samples from 12 obese horses (body condition score ≥ 7/9) and 12 nonobese horses (body condition score 4 to 5/9) with similar dietary management.

PROCEDURES

Fecal supernatant was prepared from frozen fecal samples. RAW 264.7 macrophage cells were exposed to the fecal extract. Inflammatory cytokine (interleukin-1β, tumor necrosis factor-α, and interleukin-6) gene expression was quantified via real-time quantitative reverse transcription PCR assay, and cytokine concentration was quantified via ELISA. Lipopolysaccharide was evaluated in fecal extract via chromo-limulus amoebocyte lysate assay.

RESULTS

Compared with fecal extracts from nonobese horses, fecal extracts from obese horses presented higher concentrations of lipopolysaccharide and induced a heightened expression of the proinflammatory cytokines interleukin-1β, tumor necrosis factor-α, and interleukin-6 from macrophages.

CLINICAL RELEVANCE

The increased levels of inflammatory markers induced in murine macrophages by the microbiome of obese horses in vitro suggested important differences in the enteric microbial composition of these horses, compared with nonobese horses. Overall, this study showed that the microbiome may play a role in mediating an inflammatory response within the gastrointestinal tract of obese horses. Mechanisms of obesity in the horse have not been fully elucidated. Improved understanding of the pathophysiology of disease will guide future research into potential diagnostic and therapeutic interventions for equine obesity.

Detection of lipid efflux from foam cell models using a label-free infrared method

Synchrotron-based microFTIR spectroscopy was used to study the process of lipid efflux in a foam cell model. The anti-atherosclerotic drug, atorvastatin, removed low-density lipoprotein from the foam cells in a dose, and time dependent manner.

Recent Advancements and Future Perspectives of Microalgae-Derived Pharmaceuticals

Microalgal cells serve as solar-powered factories that produce pharmaceuticals, recombinant proteins (vaccines and drugs), and valuable natural byproducts that possess medicinal properties. The main advantages of microalgae as cell factories can be summarized as follows: they are fueled by photosynthesis, are carbon dioxide-neutral, have rapid growth rates, are robust, have low-cost cultivation, are easily scalable, pose no risk of human pathogenic contamination, and their valuable natural byproducts can be further processed. Despite their potential, there are many technical hurdles that need to be overcome before the commercial production of microalgal pharmaceuticals, and extensive studies regarding their impact on human health must still be conducted and the results evaluated. Clearly, much work remains to be done before microalgae can be used in the large-scale commercial production of pharmaceuticals. This review focuses on recent advancements in microalgal biotechnology and its future perspectives.

Euglena gracilis and Its Aqueous Extract Constructed With Chitosan-Hyaluronic Acid Hydrogel Facilitate Cutaneous Wound Healing in Mice Without Inducing Excessive Inflammatory Response

Naturally occurring compounds isolated from the microalga Euglena gracilis, such as polysaccharide paramylon, exhibit antimicrobial, anti-viral, antitumor, and anti-inflammatory activities. Whether live E. gracilis cells and its aqueous extract accelerate burn wound healing remains to be investigated. In this study, live E. gracilis cells and its aqueous extract were mixed with chitosan-hyaluronic acid hydrogel (CS/HA) to form cell + CS/HA and extract + CS/HA, which were then smeared onto the deeply burned skin of mice. The efficacy of these mixtures in accelerating wound healing was assessed through wound size reduction measurement, histological and immunofluorescence analyses, and serum pro-inflammatory cytokine level (INF-γ, IL-1β, and IL-6) determination. The live E. gracilis cells and its aqueous extract were found to facilitate wound healing by enhancing re-epithelization and reducing fibroplasia without stimulating excessive inflammatory response. In conclusion, live E. gracilis cells and its aqueous extract can be potentially used to treat cutaneous wounds.

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.

Prebiotic activity of paramylon isolated from heterotrophically grown Euglena gracilis

Paramylon from Euglena gracilis is an insoluble crystalline β-1,3-glucan which have pharmaceutical and nutraceuticals applications. The present study aims to check the prebiotic potential of paramylon derived from heterotrophically grown E. gracilis in bioreactor. The Paramylon was extracted using sodium dodecyl sulfate from E. gracilis biomass. The Fourier Transform-Infra Red spectroscopy and scanning electron microscopy demonstrated the isolated paramylon to be equivalent to that of analytical standard. The prebiotic activity of E. gracilis cell extract and isolated paramylon was studied. E. gracilis cell extract as well as isolated paramylon led to cell number enhancement of Lacfid (Lactobacillus) strain exhibiting the prebiotic activities.

Metabolic Responses of a Model Green Microalga Euglena gracilis to Different Environmental Stresses

Euglena gracilis, a green microalga known as a potential candidate for jet fuel producers and new functional food resources, is highly tolerant to antibiotics, heavy metals, and other environmental stresses. Its cells contain many high-value products, including vitamins, amino acids, pigments, unsaturated fatty acids, and carbohydrate paramylon as metabolites, which change contents in response to various extracellular environments. However, mechanism insights into the cellular metabolic response of Euglena to different toxic chemicals and adverse environmental stresses were very limited. We extensively investigated the changes of cell biomass, pigments, lipids, and paramylon of E. gracilis under several environmental stresses, such as heavy metal CdCl₂, antibiotics paromomycin, and nutrient deprivation. In addition, global metabolomics by Ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was applied to study other metabolites and potential regulatory mechanisms behind the differential accumulation of major high-valued metabolites. This study collects a comprehensive update on the biology of E. gracilis for various metabolic responses to stress conditions, and it will be of great value for Euglena cultivation and high-value [154mm][10mm]Q7metabolite production.

Bis(ethylmaltolato)oxidovanadium (IV) attenuates amyloid-beta-mediated neuroinflammation by inhibiting NF-κB signaling pathway via a PPARγ-dependent mechanism

Neuroinflammation plays a pivotal role in the pathophysiology of neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease. During brain neuroinflammation, activated microglial cells resulting from amyloid-beta (Aβ) overload trigger toxic proinflammatory responses. Bis(ethylmaltolato)oxidovanadium (BEOV) (IV), an important vanadium compound, has been reported to have anti-diabetic, anti-cancer, and neuroprotective effects, but its anti-inflammatory property has rarely been investigated. In the present study, the inhibitory effects of BEOV on neuroinflammation were revealed in both Aβ-stimulated BV2 microglial cell line and APPswe/PS1E9 transgenic mouse brain. BEOV administration significantly decreased the levels of tumor necrosis factor-α, interleukin-6, interleukin-1β, inducible nitric oxide synthase, and cyclooxygenase-2 both in the hippocampus of APPswe/PS1E9 mice and in the Aβ-stimulated BV2 microglia. Furthermore, BEOV suppressed the Aβ-induced activation of nuclear factor-κB (NF-κB) signaling and upregulated the protein expression level of peroxisome proliferator-activated receptor gamma (PPARγ) in a dose-dependent manner. PPARγ inhibitor GW9662 could eliminate the effect of BEOV on Aβ-induced NF-κB activation and proinflammatory mediator production. Taken altogether, these findings suggested that BEOV ameliorates Aβ-stimulated neuroinflammation by inhibiting NF-κB signaling pathway through a PPARγ-dependent mechanism.