An antitumour lectin from the edible mushroom Agrocybe aegerita

Purification and Biochemical Characterization of Novel Galectin from the Black Poplar Medicinal Mushroom Cyclocybe cylindracea (Agaricomycetes) Strain MEST42 from Algeria

In the present study, a new galectin designated Cyclocybe cylindracea lectin (CCL) was extracted from the fruiting bodies of the wild black popular mushroom C. cylindracea grown in Algeria. The protein was isolated using sepharose 4B as affinity chromatography matrix, and galactose as elutant. The purified galectin was composed of two subunits of 17.873 kDa each, with a total molecular mass of 35.6 kDa. Its agglutinant activity was impeded by galactose and its derivatives, as well as melibiose. Lactose showed the highest affinity, with a minimal inhibitory concentration of 0.0781 mM. CCL was sensitive to extreme pH conditions, and its binding function decreased when incubated with 10 mM EDTA, and it could be restored by metallic cations such as Ca2+, Mg2+, and Zn2+. CCL agglutinated human red blood cells, without any discernible specificity. Circular dichroism spectra demonstrated that its secondary structure contained β-sheet as dominant fold. In addition, bioinformatics investigation on their peptide fingerprint obtained after MALDI-TOF/TOF ionization using mascot software confirmed that CCL was not like any previous purified lectin from mushroom: instead, it possessed an amino acid composition with high similarity to that of the putative urea carboxylase of Emericella nidulans (strain FGSC A4/ATCC 38163/CBS 112.46/NRRL 194/M139) with 44% of similarity score.

A comprehensive review of secondary metabolites from the genus Agrocybe: Biological activities and pharmacological implications

The genus Agrocybe, situated within the Strophariaceae family, class Agaricomycetes, and phylum Basidiomycota, encompasses a myriad of species exhibiting significant biological activities. This review presents an integrative overview of the secondary metabolites derived from Agrocybe species, elucidating their respective biological activities and potential pharmacological applications. The metabolites under scrutiny encompass a diverse array of biological macromolecules, specifically polysaccharides and lectins, as well as a diverse group of 80 documented small molecular chemical constituents, classified into sterols, sesquiterpenes, volatile compounds, polyenes, and other compounds, their manifesting anti-inflammatory, anticancer, antioxidant, hepatoprotective, antimicrobial, and antidiabetic activities, these metabolites, in which polysaccharides exhibit abundant activities, underscore the potential of the Agrocybe genus as a valuable source of biologically active natural products. The present review emphasises the need for escalated research into Agrocybe, including investigations into the biosynthetic pathways of these metabolites, which could foster the development of novel pharmaceutical therapies to address various health challenges.

Coprinopsis cinerea Galectin CGL1 Induces Apoptosis and Inhibits Tumor Growth in Colorectal Cancer Cells

Mushroom galectins are promising anticancer agents for their low IC50 values against cancer cells in vitro. In this study, two Coprinopsis cinerea galectins, CGL1 and CGL2, were heterologously expressed, and their biochemistry properties and anticancer effects were evaluated. The purified galectins were thermostable at neutral pH conditions. They both existed as tetramers and shared a high affinity towards lactose. CGL1 and CGL2 strongly inhibited the cell viability of many cancer cell lines, including three colorectal cancer cells, in a dose-dependent manner by inducing mitochondria-mediated caspase-dependent apoptosis. Furthermore, CGL1 exhibited higher apoptosis-inducing ability and cytotoxicity than CGL2. In vivo cell viability experiments based on two xenograft mouse models showed that CGL1 had a more substantial inhibitory effect than CGL2 on HCT116 tumor growth (p < 0.0001), whereas only CGL1 inhibited DLD1 tumor growth (p < 0.01). This is the first study to evaluate the anti-colorectal cancer effect of mushroom lectins in vivo, and our results showed that CGL1 is a potent agent for colorectal cancer treatment.

The fungal Clitocybe nebularis lectin binds distinct cell surface glycoprotein receptors to induce cell death selectively in Jurkat cells

Clitocybe nebularis lectin (CNL) is a GalNAcβ1-4GlcNAc-binding lectin that exhibits an antiproliferative effect exclusively on the Jurkat leukemic T cell line by provoking homotypic aggregation and dose-dependent cell death. Cell death of Jurkat cells exhibited typical features of early apoptosis, but lacked the activation of initiating and executing caspases. None of the features of CNL-induced cell death were effectively blocked with the pan-caspase inhibitor or different cysteine peptidase inhibitors. Furthermore, CNL binding induced Jurkat cells to release the endogenous damage-associated molecular pattern molecule high-mobility group box 1 (HMGB1). A plant lectin with similar glycan-binding specificity, Wisteria floribunda agglutinin (WFA) showed less selective toxicity and induced cell death in Jurkat, Tall-104, and Hut-87 cell lines. HMGB1 release was also detected when Jurkat cells were treated with WFA. We identified the CD45 and CD43 cell surface glycoproteins on Jurkat cells as the main targets for CNL binding. However, the blockade of CD45 phosphatase activity failed to block either CNL-induced homotypic agglutination or cell death. Overall, our results indicate that CNL triggers atypical cell death selectively on Jurkat cells, suggesting the potential applicability of CNL in novel strategies for treating and/or detecting acute T cell leukemia.

Purification and characterization of a synergistic bioactive lectin from Pleurotus flabellatus (PFL-L) with potent antibacterial and in-vitro radical scavenging activity

Lectin is a carbohydrate-binding protein, which exhibits a plethora of biological properties such as antimicrobial, antifungal, and anticancer activities. In the present study, lectin, with an antibacterial and antioxidant potential, was purified from the oyster mushroom Pleurotus flabellatus. The P. flabellatus Lectin (PFL-L) was purified by using a DEAE - cellulose anion exchange chromatography followed by gel-filtration chromatography. The PFL-L was characterized by CD, HPLC, and MALDI-TOF/MS. The purity of PFL-L increased to 62.40% with the recovery of hemagglutinating activity (HA) by 12.12%. On SDS - PAGE, the PFL-L gave a single band of 18 kDa. PFL-L, consisting of d-galactose, exhibits a strong hemagglutinating activity. It was stable at pH (6.0-7.5) and temperature (10-20 °C) in addition to having extensive hemagglutinating activity. PFL-L enhanced the HA with the use of different metal ions namely Mg²⁺, Ca^2+, and Fe²⁺. The study of bacterial growth inhibition led to the inference that the PFL-L was more potent against gram-negative bacteria. PFL-L showed the highest radical scavenging activity for the DPPH assay at 100 μg/mL (89.9 ± 2.53%). The highest antioxidant activities with IC₅₀ values (for DPPH assay) of 53.96 μg/mL were determined for PFL-L and the present study shows that lectin from P. flabellatus manifested distinctive character and potentially exploitable activities.

Rhizoctonia bataticola lectin induces apoptosis and inhibits metastasis in ovarian cancer cells by interacting with CA 125 antigen differentially expressed on ovarian cells

A N-glycan specific lectin from Rhizoctonia bataticola [RBL] was shown to induce growth inhibitory and apoptotic effect in human ovarian, colon and leukemic cells but mitogenic effect on normal PBMCs as reported earlier, revealing its clinical potential. RBL has unique specificity for high mannose tri and tetra antennary N-glycans, expressed in ovarian cancer and also recognizes glycans which are part of CA 125 antigen, a well known ovarian cancer marker. Hence, in the present study diagnostic and therapeutic potential of RBL was investigated using human ovarian epithelial cancer SKOV3 and OVCAR3 cells known for differentially expressing CA 125. RBL binds differentially to human ovarian normal, cyst and cancer tissues. Flow cytometry, western blot analysis of membrane proteins showed the competitive binding of RBL and CA 125 antibody for the same binding sites on SKOV3 and OVCAR3 cells. RBL has strong binding to both SKOV3 and OVCAR3 cells with MFI of 173 and 155 respectively. RBL shows dose and time dependent growth inhibitory effect with IC₅₀ of 2.5 and 8 μg/mL respectively for SKOV3 and OVCAR3 cells. RBL induces reproductive cell death, morphological changes, nuclear degradation and increased release of ROS in SKOV3 and OVCAR3 cells leading to cell death. This is also supported by increase in hypodiploid population, altered MMP leading to apoptosis possibly involving intrinsic pathway. Adhesion, wound healing, invasion and migration assays demonstrated anti-metastasis effect of RBL apart from its growth inhibitory effect. These results show the promising potential of RBL both as a diagnostic and therapeutic agent.

Narrative Review: Bioactive Potential of Various Mushrooms as the Treasure of Versatile Therapeutic Natural Product

Mushrooms have remained an eternal part of traditional cuisines due to their beneficial health potential and have long been recognized as a folk medicine for their broad spectrum of nutraceuticals, as well as therapeutic and prophylactic uses. Nowadays, they have been extensively investigated to explain the chemical nature and mechanisms of action of their biomedicine and nutraceuticals capacity. Mushrooms belong to the astounding dominion of Fungi and are known as a macrofungus. Significant health benefits of mushrooms, including antiviral, antibacterial, anti-parasitic, antifungal, wound healing, anticancer, immunomodulating, antioxidant, radical scavenging, detoxification, hepatoprotective cardiovascular, anti-hypercholesterolemia, and anti-diabetic effects, etc., have been reported around the globe and have attracted significant interests of its further exploration in commercial sectors. They can function as functional foods, help in the treatment and therapeutic interventions of sub-optimal health states, and prevent some consequences of life-threatening diseases. Mushrooms mainly contained low and high molecular weight polysaccharides, fatty acids, lectins, and glucans responsible for their therapeutic action. Due to the large varieties of mushrooms present, it becomes challenging to identify chemical components present in them and their beneficial action. This article highlights such therapeutic activities with their active ingredients for mushrooms.

3'-Sulfo-TF Antigen Determined by GAL3ST2/ST3GAL1 Is Essential for Antitumor Activity of Fungal Galectin AAL/AAGL

Many lectins have been reported to have antitumor activities; identifying the glycan ligands in tumor cells of lectins is crucial for lectin clinical application. An edible mushroom galectin, Agrocybe aegerita lectin (AAL/AAGL), that has a high antitumor activity has been reported. In this paper, based on the glycan array data, it is showed that the Thomsen-Friedenreich antigen (TF antigen)-related O-glycans were found to be highly correlated with the antitumor activity of AAL/AAGL. Further glycosyltransferase quantification suggested that the ratio between GAL3ST2 and ST3GAL1 (GAL3ST2/ST3GAL1), which determined the 3'-sulfo-TF expression level, was highly correlated with the antitumor activity of AAL/AAGL. Overexpressing the enzyme of GAL3ST2 in HL60 and HeLa cell lines could increase the growth inhibition ratio of AAL/AAGL from 22.7 to 43.9% and 27.8 to 39.1%, respectively. However, ST3GAL1 in Jurkat cells could decrease the growth inhibition ratio from 44.7 to 35.6%. All the data suggested that the 3'-sulfo-TF antigen is one of the main glycan ligands that AAL/AAGL recognizes in tumor cells. AAL/AAGL may potentially serve as a reagent for cancer diagnosis and a targeted therapy for the 3'-sulfo-TF antigen.

A New Lectin from Auricularia auricula Inhibited the Proliferation of Lung Cancer Cells and Improved Pulmonary Flora

Lectins are widely distributed in the natural world and are usually involved in antitumor activities. Auricularia auricula (A. auricula) is a medicinal and edible homologous fungus. A. auricula contains many active ingredients, such as polysaccharides, melanin, flavonoids, adenosine, sterols, alkaloids, and terpenes. In this study, we expected to isolate and purify lectin from A. auricula, determine the glycoside bond type and sugar-specific protein of A. auricula lectin (AAL), and finally, determine its antitumor activities. We used ammonium sulfate fractionation, ion exchange chromatography, and affinity chromatography to separate and purify lectin from A. auricula. The result was a 25 kDa AAL with a relative molecular mass of 18913.22. Protein identification results suggested that this lectin contained four peptide chains by comparing with the UniProt database. The FT-IR and β-elimination reaction demonstrated that the connection between the oligosaccharide and polypeptide of AAL was an N-glucoside bond. Analyses of its physical and chemical properties showed that AAL was a temperature-sensitive and acidic/alkaline-dependent glycoprotein. Additionally, the anticancer experiment manifested that AAL inhibited the proliferation of A549, and the IC50 value was 28.19 ± 1.92 μg/mL. RNA sequencing dataset analyses detected that AAL may regulate the expression of JUN, TLR4, and MYD88 to suppress tumor proliferation. Through the pulmonary flora analysis, the bacterial structure of each phylum in the lectin treatment group was more reasonable, and the colonization ability of the normal microflora was improved, indicating that lectin treatment could significantly improve the bacterial diversity characteristics.

Lectins purified from medicinal and edible mushrooms: Insights into their antiviral activity against pathogenic viruses

For thousands of years, fungi have been a valuable and promising source of therapeutic agents for treatment of various diseases. Mushroom is a macrofungus which has been cultivated worldwide for its nutritional value and medicinal applications. Several bioactive molecules were extracted from mushroom such as polysaccharides, lectins and terpenoids. Lectins are carbohydrate-binding proteins with non-immunologic origin. Lectins were classified according to their structure, origin and sugar specificity. This protein has different binding specificity with surface glycan moiety which determines its activity and therapeutic applications. A wide range of medicinal activities such as antitumor, antiviral, antimicrobial, immunomodulatory and antidiabetic were reported from sugar-binding proteins. However, glycan-binding protein from mushroom is not well explored as antiviral agent. The discovery of novel antiviral agents is a public health emergency to overcome the current pandemic and be ready for the upcoming viral pandemics. The mechanism of action of lectin against viruses targets numerous steps in viral life cycle such as viral attachment, entry and replication. This review described the history, classification, purification techniques, structure-function relationship and different therapeutic applications of mushroom lectin. In addition, we focus on the antiviral activity, purification and physicochemical characteristics of some mushroom lectins.

Chemopreventive activity of bioactive fungal fractions isolated from milk-supplemented cultures of Cerrena unicolor and Pycnoporus sanguineus on colon cancer cells

The biochemical properties and anti-tumorigenic activity of Cerrena unicolor (CU) and Pycnoporus sanguineus (PS) towards colon cancer cells and the effect of supplementation of the fungal culture medium with cow milk on these activities were examined. CU1-II and PS4-II exhibited anticancer properties through various mechanisms. The extracts at the 200 µg/mL concentration significantly decreased the viability of HT-29 and SW948 cells. They also exhibited pro-apoptotic properties towards the cancer cell lines (HT-29, LS 180, and SW948). Furthermore, culturing the studied fungi on milk-supplemented media may improve the pro-health properties of both milk and mushrooms. The extracts had a higher concentration of proteins, lower levels of free amino acids, and higher content of phenolic compounds than milk. They also exerted a free radical scavenging effect, which may be connected with the high activity of catalase and superoxide dismutase. The tested extracts exhibited anticancer activity: C. unicolor grown on the medium without milk and P. sanguineus grown on the medium with milk. The CU1-II and PS4-II extracts exhibited the strongest anticancer properties; however, PS4-II exerted a milder effect on normal CCD 841 CoTr cells than CU1-II. CU3-II exerted the mildest effect among all extracts on both normal and cancer cells.

Immunomodulatory Effects of Edible and Medicinal Mushrooms and Their Bioactive Immunoregulatory Products

Mushrooms have been valued as food and health supplements by humans for centuries. They are rich in dietary fiber, essential amino acids, minerals, and many bioactive compounds, especially those related to human immune system functions. Mushrooms contain diverse immunoregulatory compounds such as terpenes and terpenoids, lectins, fungal immunomodulatory proteins (FIPs) and polysaccharides. The distributions of these compounds differ among mushroom species and their potent immune modulation activities vary depending on their core structures and fraction composition chemical modifications. Here we review the current status of clinical studies on immunomodulatory activities of mushrooms and mushroom products. The potential mechanisms for their activities both in vitro and in vivo were summarized. We describe the approaches that have been used in the development and application of bioactive compounds extracted from mushrooms. These developments have led to the commercialization of a large number of mushroom products. Finally, we discuss the problems in pharmacological applications of mushrooms and mushroom products and highlight a few areas that should be improved before immunomodulatory compounds from mushrooms can be widely used as therapeutic agents.

Multilocus phylogeny- and fruiting feature-assisted delimitation of European Cyclocybe aegerita from a new Asian species complex and related species

Cyclocybe aegerita (synonym: Agrocybe aegerita) is a widely cultivated edible and reportedly almost cosmopolitan mushroom species that serves as a model fungus for basidiome formation and as producer of useful natural products and enzymes. Focusing on strains from different continents, here, we present a phylogenetic analysis of this species and some adjacent taxa that employs four phylogenetic markers. In addition, we tested the strains’ capability to fructify on agar media. Our analysis reveals that “C. aegerita sensu lato” splits up into the following two well-supported monophyletic geographic lineages: a European clade and an Asian clade. The European one is closely associated with the Chinese species Cyclocybe salicaceicola. In contrast, the Asian lineage, which we preliminarily designate as Cyclocybe chaxingu agg., may comprise several species (species complex) and clusters with the Pacific species Cyclocybe parasitica (New Zealand). In addition, fruiting properties differ across C. aegerita and its Asian and Pacific relatives; however, strains from the Asian clade and C. parasitica tend to form larger basidiomes with relatively big caps and long stipes and strains from the European clade exhibit a more variable fruiting productivity with the tendency to form more basidiomes, with smaller caps and shorter stipes. Moreover, some strains showed individual fruiting patterns, such as the preference to fruit where they were exposed to injuring stimuli. In conclusion, the delimitation of the newly delimited Asian species complex from our multilocus phylogeny of “C. aegerita sensu lato”, which is supported by phenotypic data, depicts an exemplary case of biogeographic diversity within a previously thought homogeneous species of near worldwide distribution.

Critical role of IL-1β in the pathogenesis of Agrocybe aegerita galectin-induced liver injury through recruiting T cell to liver

Acute liver failure (ALF) can be the consequence of various etiologies, which immune response plays a pivotal role in the pathogenesis. For the diversity of etiologies, more animal models are still needed in this field. Here, we developed a new acute liver injury mouse model induced by a fungal lectin AAGL (Agrocybe aegerita galectin). Intravenous injection of AAGL could induce the infiltration and activation of T, NKT and NK cells in liver and T cell played an important role in the pathogenesis. However, compared with the widely used concanavalin A model, AAGL model showed different immune mechanism. Transcriptome analysis of live tissue suggested that inflammation mediated by chemokine and cytokine signaling pathway was different between AAGL and Con A model. Fluorescent quantitative PCR verification assay showed that IL-1β was expressed much higher in AAGL-treated mice and anti-IL-1β could ameliorate AAGL-induced liver injury by inhibiting NF-κB and p38 signaling pathway. The expression of CXCL9 which was responsible for T cell infiltration in liver was also inhibited in AAGL model. We found a critical role of IL-1β in the pathogenesis of AAGL model through recruiting T cells to liver, which highlighted that IL-1β antibody might be a candidate therapy for ALF.

Investigation of TF-binding lectins from dietary sources and SRL on proliferation and cell cycle progression in human colon HT29 and SW620 cells

TF antigen binding lectins from dietary sources PNA, ACA, ABL, JAC, and SRL from Sclerotium rolfsii have been reported to induce diverse effects on cancer cell proliferation by different mechanisms. This study aimed to compare effects of these lectins on growth and cell cycle progression in colon cancer HT29 and SW620 cells. As reported SRL, ABL, and JAC inhibited while PNA and ACA increased cell proliferation. ABL and JAC treated HT29 cells showed increased cell population in G0/G1 phase. PNA, ACA, ABL, and JAC increased SW620 cell population in S and decreased in G2/M phase. In contrast, SRL and JAC increased hypodiploid population in both the cells. PNA and ACA reduced whereas SRL and ABL diminished cell cyclin D1 expression. SRL, PNA, and ACA also reduced cellular cyclin D3 level while SRL, ABL, and JAC reduced cyclin E levels. ABL decreased CDK5 levels while SRL and ACA completely abolished CDK5 expression. All the lectins completely abolished cyclin D2 expression. These results not only confirms growth regulatory effects of TF-binding lectins but also indicates different effects of these lectins on cell growth is associated with regulation on expression of cell cycle associated proteins in G1-S phase and on cell cycle progression.

Cloning and expression of the lectin gene from the mushroom Agrocybe aegerita and the activities of recombinant lectin in the resistance of shrimp white spot syndrome virus infection

Lectin is a protein with multiple functions. In this study, the full-length cDNA of the Agrocybe aegerita lectin (AAL) gene was cloned, recombinant AAL (AAL-His) was expressed, and the activities of AAL-His were analyzed. Northern blot analysis showed that the major AAL transcript is approximately 900 bp. Sequence analysis showed that the coding region of AAL is 489 bp with a transcription start site located 39 nucleotides upstream of the translation initiation codon. In an agglutination test, AAL-His agglutinated rabbit erythrocytes at 12.5 μg/ml. AAL-His also showed antiviral activity in protecting shrimp from white spot syndrome virus (WSSV) infection. This anti-WSSV effect might be due to the binding of AAL-His on WSSV virions via the direct interactions with four WSSV structural proteins, VP39B, VP41B, VP53A and VP216. AAL demonstrates the potential for development as an anti-WSSV agent for shrimp culture. It also implies that these four AAL interaction WSSV proteins may play important roles in virus infection.

Purification and characterization of a novel ubiquitin-like antitumour protein with hemagglutinating and deoxyribonuclease activities from the edible mushroom Ramaria botrytis

A novel ubiquitin-like antitumour protein (RBUP) was isolated from fruiting bodies of the edible mushroom Ramaria botrytis. The protein was isolated with a purification protocol involving ion exchange chromatography on DEAE-Sepharose fast flow and gel filtration on Sephadex G-75. SDS-PAGE, Native-PAGE and ultracentrifugation analysis disclosed that RBUP was a monomeric protein with a molecular weight of 18.5 kDa. ESI-MS/MS demonstrated that it shared 69% amino acid sequence similarity with Coprinellus congregates ubiquitin (gi|136667). The protein exhibiting strong anticancer activity towards A549 cells. Analysis by employing AO/EB staining and Annexin V-FITC/PI detection indicated that the cytotoxic effect of RBUP was mediated through induction of apoptosis. Furthermore, RBUP displayed hemagglutinating and deoxyribonuclease activities. A temperature of 40 °C and pH of 7.0 were required for optimal DNase activity. Therefore, it was estimated that RBUP exerted its antitumour effect by inducing apoptosis, and its hemagglutinating and DNase activities were also thought to participate in this effect. These results demonstrated that RBUP was a multifunctional protein with potential medicinal applications.

The complete mitochondrial genome of the Agrocybe aegerita, an edible mushroom

Agrocybe aegerita is a medicinally and nutritionally important edible basidiomycete. Despite previous phylogenetic studies, the taxonomy of A. aegerita complex remains unclear due to lacking of resolutive data. Herein, the complete mitochondrial genome of A. aegerita is reported and analyzed. The mitogenome length was 116,329 bp, with a GC content of 27.6%, include 17 typical protein-coding genes, two ribosomal protein genes (rps3), two ribosomal RNA genes and a set of 32 transfer RNA genes. A phylogenetic analyses using complete mitogenome in Agaricales showed that A. aegerita is closely related to the genus Pleurotus and represents a clade clearly independent from other Agaricales species.

Adjuvant effects mediated by the carbohydrate recognition domain of Agrocybe aegerita lectin interacting with avian influenza H9N2 viral surface glycosylated proteins

OBJECTIVE

To evaluate the potential adjuvant effect of Agrocybe aegerita lectin (AAL), which was isolated from mushroom, against a virulent H₉N₂ strain in vivo and in vitro.

METHODS

In trial 1, 50 BALB/c male mice (8 weeks old) were divided into five groups (n=10 each group) which received a subcutaneous injection of inactivated H₉N₂ (control), inactivated H₉N₂+0.2% (w/w) alum, inactivated H₉N₂+0.5 mg recombinant AAL/kg body weight (BW), inactivated H₉N₂+1.0 mg AAL/kg BW, and inactivated H₉N₂+2.5 mg AAL/kg BW, respectively, four times at 7-d intervals. In trial 2, 30 BALB/c male mice (8 weeks old) were divided into three groups (n=10 each group) which received a subcutaneous injection of inactivated H₉N₂ (control), inactivated H₉N₂+2.5 mg recombinant wild-type AAL (AAL-wt)/kg BW, and inactivated H₉N₂+2.5 mg carbohydrate recognition domain (CRD) mutant AAL (AAL-mutR63H)/kg BW, respectively, four times at 7-d intervals. Seven days after the final immunization, serum samples were collected from each group for analysis. Hemagglutination assay, immunogold electron microscope, lectin blotting, and co-immunoprecipitation were used to study the interaction between AAL and H₉N₂ in vitro.

RESULTS

IgG, IgG1, and IgG2a antibody levels were significantly increased in the sera of mice co-immunized with inactivated H₉N₂ and AAL when compared to mice immunized with inactivated H₉N₂ alone. No significant increase of the IgG antibody level was detected in the sera of the mice co-immunized with inactivated H₉N₂ and AAL-mutR63H. Moreover, AAL-wt, but not mutant AAL-mutR63H, adhered to the surface of H₉N₂ virus. The interaction between AAL and the H₉N₂ virus was further demonstrated to be associated with the CRD of AAL binding to the surface glycosylated proteins, hemagglutinin and neuraminidase.

CONCLUSIONS

Our findings indicated that AAL could be a safe and effective adjuvant capable of boosting humoral immunity against H₉N₂ viruses in mice through its interaction with the viral surface glycosylated proteins, hemagglutinin and neuraminidase.

Macrophage Inducible C-Type Lectin As a Multifunctional Player in Immunity

The macrophage-inducible C-type lectin (Mincle) is an innate immune receptor on myeloid cells sensing diverse entities including pathogens and damaged cells. Mincle was first described as a receptor for the mycobacterial cell wall glycolipid, trehalose-6,6′-dimycolate, or cord factor, and the mammalian necrotic cell-derived alarmin histone deacetylase complex unit Sin3-associated protein 130. Upon engagement by its ligands, Mincle induces secretion of innate cytokines and other immune mediators modulating inflammation and immunity. Since its discovery more than 25 years ago, the understanding of Mincle’s immune function has made significant advances in recent years. In addition to mediating immune responses to infectious agents, Mincle has been linked to promote tumor progression, autoimmunity, and sterile inflammation; however, further studies are required to completely unravel the complex role of Mincle in these distinct host responses. In this review, we discuss recent findings on Mincle’s biology with an emphasis on its diverse functions in immunity.

Plant Lectins Targeting O-Glycans at the Cell Surface as Tools for Cancer Diagnosis, Prognosis and Therapy

Aberrant O-glycans expressed at the surface of cancer cells consist of membrane-tethered glycoproteins (T and Tn antigens) and glycolipids (Lewis a, Lewis x and Forssman antigens). All of these O-glycans have been identified as glyco-markers of interest for the diagnosis and the prognosis of cancer diseases. These epitopes are specifically detected using T/Tn-specific lectins isolated from various plants such as jacalin from Artocarpus integrifola, and fungi such as the Agaricus bisporus lectin. These lectins accommodate T/Tn antigens at the monosaccharide-binding site; residues located in the surrounding extended binding-site of the lectins often participate in the binding of more extended epitopes. Depending on the shape and size of the extended carbohydrate-binding site, their fine sugar-binding specificity towards complex O-glycans readily differs from one lectin to another, resulting in a great diversity in their sugar-recognition capacity. T/Tn-specific lectins have been extensively used for the histochemical detection of cancer cells in biopsies and for the follow up of the cancer progression and evolution. T/Tn-specific lectins also induce a caspase-dependent apoptosis in cancer cells, often associated with a more or less severe inhibition of proliferation. Moreover, they provide another potential source of molecules adapted to the building of photosensitizer-conjugates allowing a specific targeting to cancer cells, for the photodynamic treatment of tumors.

Pharmacokinetics, biodistribution and antitumour effects of Sclerotium rolfsii lectin in mice

Sclerotium rolfsii lectin (SRL) is a lectin isolated from the fungus Sclerotium rolfsii and has exquisite binding specificity towards the oncofetal Thomsen-Friedenreich antigen (TF-Ag; Galβ1-3GalNAcα-O-Ser/Thr) and its derivatives. Previous studies have shown that SRL inhibits the proliferation of human colon, breast and ovarian cancer cells in vitro and suppresses tumour growth in mice when introduced intratumourally. The present study assessed the effect of SRL on tumour growth when introduced intraperitoneally in BALB/c nude mice and investigated the pharmacokinetics and biodistribution of SRL in Swiss albino mice. When 9 doses of SRL (30 mg/kg body weight/mice) was administered to BALB/c nude mice bearing human colon cancer HT-29 xenografts, a substantial reduction in tumour size was observed. A 35.8% reduction in tumour size was noted in the treated animals after 17 days. SRL treatment also inhibited angiogenesis, and the tumours from the treated animals were observed to carry fewer blood vessels and express less angiogenesis marker protein CD31, than that from the control animals. Pharmacokinetics and biodistribution analysis revealed that SRL was detected in the serum after 1 h and its level peaked after 24 h. SRL was not detected in any of the organs apart from the kidney where a trace amount was detected after 24 h of SRL injection. No significant changes were observed in any of the biochemical parameters tested including SGOT, SGPT, LDH, CREAT and BUN in the SRL-treated mice compared to these levels in the controls. This suggests that SRL has good potential to be developed as a therapeutic agent for cancer treatment and warrant further investigations in vivo and subsequent clinical trials.

Lectins, Interconnecting Proteins with Biotechnological/Pharmacological and Therapeutic Applications

Lectins are proteins extensively used in biomedical applications with property to recognize carbohydrates through carbohydrate-binding sites, which identify glycans attached to cell surfaces, glycoconjugates, or free sugars, detecting abnormal cells and biomarkers related to diseases. These lectin abilities promoted interesting results in experimental treatments of immunological diseases, wounds, and cancer. Lectins obtained from virus, microorganisms, algae, animals, and plants were reported as modulators and tool markers in vivo and in vitro; these molecules also play a role in the induction of mitosis and immune responses, contributing for resolution of infections and inflammations. Lectins revealed healing effect through induction of reepithelialization and cicatrization of wounds. Some lectins have been efficient agents against virus, fungi, bacteria, and helminths at low concentrations. Lectin-mediated bioadhesion has been an interesting characteristic for development of drug delivery systems. Lectin histochemistry and lectin-based biosensors are useful to detect transformed tissues and biomarkers related to disease occurrence; antitumor lectins reported are promising for cancer therapy. Here, we address lectins from distinct sources with some biological effect and biotechnological potential in the diagnosis and therapeutic of diseases, highlighting many advances in this growing field.

Identification of GlcNAcylated alpha-1-antichymotrypsin as an early biomarker in human non-small-cell lung cancer by quantitative proteomic analysis with two lectins

Background:

Non-small-cell lung cancer (NSCLC) is the main type of lung cancer with high mortality rates in worldwide. There is a need to identify better biomarkers to detect NSCLC at an early stage as this will improve therapeutic effect and patient survival rates.

Methods:

Two lectins (AAL/AAGL and AAL2/AANL), which specifically bind to tumour-related glycan antigens, were first used to enrich serum glycoproteins from the serum of early NSCLC patients, benign lung diseases subjects and healthy individuals. The samples were investigated by using iTRAQ labelling and LC-MS/MS.

Results:

A total of 53 differentially expressed proteins were identified by quantitative proteomics and four glycoproteins (AACT, AGP1, CFB and HPX) were selected for further verification by western blotting. Receiver operating characteristic analysis showed AACT was the best candidate for early NSCLC diagnosis of the four proteins, with 94.1% sensitivity in distinguishing early tumour Stage (IA+IB) from tumour-free samples (healthy and benign samples, HB). The GlcNAcylated AACT was further detected by lectin-based ELISA and has better advantage in clinical application than total AACT. The GlcNAcylated AACT can effectively differentiate Stage I from HB samples with an AUC of 0.908 and 90.9% sensitivity at a specificity of 86.2%. A combination of GlcNAcylated AACT and carcinoembryonic antigen (CEA) was able to effectively differing Stage I from HB samples (AUC=0.914), which significantly improve the specificity of CEA. The combination application also has the better clinical diagnostic efficacy in distinguishing cancer (NSCLC) from HB samples than CEA or GlcNAcylated AACT used alone, and yielded an AUC of 0.817 with 93.1% specificity.

Conclusions:

Our findings suggest that the GlcNAcylated AACT will be a promising clinical biomarker in diagnosis of early NSCLC.

AAL exacerbates pro-inflammatory response in macrophages by regulating Mincle/Syk/Card9 signaling along with the Nlrp3 inflammasome assembly

Previously, we demonstrated that Agrocybe aegerita lectin (AAL), a galectin isolated from edible mushroom Agrocybe aegerita, exerts potent anti-tumor activity, while the mechanisms by which AAL suppresses tumor growth are yet to be elucidated. Here, we conducted studies with focus for its impact on the cecal ligation and puncture (CLP)-induced innate immune response. Administration of AAL significantly exacerbated the severity of CLP-induced septic shock as manifested the increased lethality. AAL promoted inflammatory cytokine production by preferentially regulating macrophage activation and recruitment. Mechanistic studies revealed that AAL likely targets macrophages through receptor Mincle to activate Syk/Card9 signaling, which then couples to the Nlrp3 inflammasome assembly. It was further noted that AAL markedly promotes H3K4 di- and trimethylation, by which it enhances Hmgb1 expression. Specifically, AAL induced macrophages secretion of copious amount of Hmgb1 as manifested the Hmgb1 cytoplasmic translocation along with the detection of extracellular Hmgb1. AAL also stimulated a significant increase for nuclear Hmgb1, which then formed a complex with RelA, and thereby enhancing NF-κB transcriptional activity. Together, our data suggest that AAL may possess important pharmaceutical properties in the regulation of innate immune response.

Nutritional value, chemical composition, antioxidant activity and enrichment of cream cheese with chestnut mushroom Agrocybe aegerita (Brig.) Sing

A very well-known and appreciated mushroom, Agrocybe aegerita (Brig.) Sing, was the subject of chemical profiling, antioxidant assays and sensory evaluation test in cream cheese. Methanolic extract obtained from a wild sample of A. aegerita fruiting body was fully chemically identified. Sample was found to be rich in carbohydrates (84.51 g/100 g dw), ash and proteins (6.69 g/100 g dw and 6.68 g/100 g dw, respectively). Trehalose was the main free sugar while malic acid was the most abundant organic acid. Four isoforms of tocopherols were identified; γ- tocopherol was the dominant isoform with 86.08 μg/100 g dw, followed by β- tocopherol, δ-tocopherol and α-tocopherol (8.80 μg/100 g dw, 3.40 μg/100 g dw and 2.10 μg/100 g dw, respectively). Polyunsaturated fatty acids were predominant, with linoleic acid as the most prominent one (78.40 %). Methanolic extract of chestnut mushroom exhibited high antioxidant activity. Sensory evaluation test included grading by panelists and comparing the overall acceptability of cream cheese alone and enriched cream cheese with dry powder of A. aegerita. General conclusion of the participants was that the newly developed product was more likeable in comparison to cream cheese alone. Due to the health-beneficial effects of antioxidants and wealth of chemically identified nutrients, A. aegerita is a promising starting material for incorporation on larger scale products.

Xylaria hypoxylon Lectin as Adjuvant Elicited Tfh Cell Responses

Foot-and-mouth disease (FMD) caused by FMD virus (FMDV) is a major health and economic problem in the farming industry. Vaccination of livestock against this highly infectious viral disease is crucial, and inactivated FMD vaccine has been effective at controlling infection. However, accumulated data show that the inactivated vaccine generates weak immune responses and that the oil formulation results in undesirable side effects. Mushroom lectins have recently been shown to display adjuvant effects when incorporated into DNA vaccines. In this study, to enhance the cellular immune response of FMDV antigen (146S), C57BL/6 mice were immunized with 146S combined with Xylaria hypoxylon lectin (XHL). The oil formulation (146S/Oil) was served as control group. Strong humoral immune responses were elicited in mice immunized with 146S/XHL as shown by high 146S antigen-specific IgG levels, and also in 146S/Oil group. Interestingly, XHL in conjunction with inactivated FMD vaccine activated strong Th1 and Tc1 cell responses, especially Tfh cell responses, in immunized mice. XHL stimulated dendritic cell maturation by upregulating expression of major histocompatibility complex II (MHCII) molecules and co-stimulatory molecules CD40 and CD86 in immunized mice. No XHL-specific IgG or inflammatory factors were detected indicating the safety of XHL as an adjuvant. Taken together, these results suggest the effectiveness of XHL at inducing cellular immune responses and therefore confirm its suitability as an adjuvant for inactivated FMD vaccine.

Bioactive composition, antimicrobial activities and the influence of Agrocybe aegerita (Brig.) Sing on certain quorum-sensing-regulated functions and biofilm formation by Pseudomonas aeruginosa

Agrocybe aegerita (Brig.) Sing is a basidiomycete, white rot fungus. Antimicrobial activities and the antiqourum effect on Pseudomonas aeruginosa of an A. aegerita methanolic extract were investigated. The extract showed very good antimicrobial activity against all the tested microorganisms in a dose dependent manner. Effects of the Sub-MIC, MIC and 2MIC of the A. aegerita methanolic extract regulated the virulence factors in the quorum sensing (QS) test, as well as biofilm formation on P. aeruginosa. Sub-inhibitory and inhibitory concentrations of the extract demonstrated the reduction of virulence factors such as pyocyanin production, twitching and swimming motility. The biofilm forming capability of P. aeruginosa PAO1 was also reduced in a concentration-dependent manner. Furthermore, the chemical composition of the methanolic extract was determined considering its phenolic composition. The methanolic extract of A. aegerita can be a very good source of bioactive substances. This research is of great importance due to the prevalence of drug-resistant microorganisms.

Lectin from Agrocybe aegerita as a glycophenotype probe for evaluation of progression and survival in colorectal cancer

BACKGROUND

Agrocybe aegerita Lectin (AAL) has been identified to have high affinity for sulfated and α2-3- linked sialic acid glycoconjugates, especially the sulfated and sialyl TF (Thomsen-Friedenreich) disaccharide. This study was conducted to investigate the clinicopathological and prognostic value of AAL in identifying aberrant glycosylation in colorectal cancer (CRC).

MATERIALS AND METHODS

Glycoconjugate expression in 59 CRC tissues were detected using AAL-histochemistry. Clinicopathological associates of expression were analyzed with chi- square test or Fisher's exact test. Relationships between expression and the various clinicopathological parameters was estimated using Kaplan-Meier analysis and Cox regression models.

RESULTS

AAL specific glycoconjugate expression was significantly higher in tumor than corresponding normal tissues (66.1% and 46.1%, respectively, p=0.037), correlating with depth of invasion (p=0.015) and TNM stage (p=0.024). Patients with lower expression levels had a significantly higher survival rate than those with higher expression (p=0.046 by log rank test and p=0.047 by Breslow test for overall survival; p=0.054 by log rank test and P=0.038 by Breslow test for progress free survival). A marginally significant association was found between AAL specific glycoconjugate expression and overall survival by univariate Cox regression analysis (p=0.059).

CONCLUSIONS

Lower AAL specific glycoconjugate expression is a significant favorable prognostic factor for overall and progress free survival in CRC. This is the first report about the employment of AAL for histochemical analysis of cancer tissues. The binding characteristics of AAL means it has potential to become a powerful tool for the glycan investigation and clinical application.

Mushroom lectins: specificity, structure and bioactivity relevant to human disease

Lectins are non-immunoglobulin proteins that bind diverse sugar structures with a high degree of selectivity. Lectins play crucial role in various biological processes such as cellular signaling, scavenging of glycoproteins from the circulatory system, cell-cell interactions in the immune system, differentiation and protein targeting to cellular compartments, as well as in host defence mechanisms, inflammation, and cancer. Among all the sources of lectins, plants have been most extensively studied. However, more recently fungal lectins have attracted considerable attention due to their antitumor, antiproliferative and immunomodulatory activities. Given that only 10% of mushroom species are known and have been taxonomically classified, mushrooms represent an enormous unexplored source of potentially useful and novel lectins. In this review we provide an up-to-date summary on the biochemical, molecular and structural properties of mushroom lectins, as well as their versatile applications specifically focusing on mushroom lectin bioactivity.

Proteome exploration to provide a resource for the investigation of Ganoderma lucidum

Ganoderma lucidum is a basidiomycete white rot fungus that has been used for medicinal purposes worldwide. Although information concerning its genome and transcriptome has recently been reported, relatively little information is available for G. lucidum at the proteomic level. In this study, protein fractions from G. lucidum at three developmental stages (16-day mycelia, and fruiting bodies at 60 and 90 days) were prepared and subjected to LC-MS/MS analysis. A search against the G. lucidum genome database identified 803 proteins. Among these proteins, 61 lignocellulose degrading proteins were detected, most of which (49 proteins) were found in the 90-day fruiting bodies. Fourteen TCA-cycle related proteins, 17 peptidases, two argonaute-like proteins, and two immunomodulatory proteins were also detected. A majority (470) of the 803 proteins had GO annotations and were classified into 36 GO terms, with "binding", "catalytic activity", and "hydrolase activity" having high percentages. Additionally, 357 out of the 803 proteins were assigned to at least one COG functional category and grouped into 22 COG classifications. Based on the results from the proteomic and sequence alignment analyses, a potentially new immunomodulatory protein (GL18769) was expressed and shown to have high immunomodulatory activity. In this study, proteomic and biochemical analyses of G. lucidum were performed for the first time, revealing that proteins from this fungus can play significant bioactive roles and providing a new foundation for the further functional investigations that this fungus merits.

Lectins from edible mushrooms

Mushrooms are famous for their nutritional and medicinal values and also for the diversity of bioactive compounds they contain including lectins. The present review is an attempt to summarize and discuss data available on molecular weights, structures, biological properties, N-terminal sequences and possible applications of lectins from edible mushrooms. It further aims to update and discuss/examine the recent advancements in the study of these lectins regarding their structures, functions, and exploitable properties. A detailed tabling of all the available data for N-terminal sequences of these lectins is also presented here.

Isolation and characterization of a novel lectin from the edible mushroom Stropharia rugosoannulata

To date, only a few steroids have been isolated from the mushroom Stropharia rugosoannulata which can be cultivated. In this paper, a novel lectin (SRL) with a molecular weight of 38 kDa, and a unique IKSGVYRIVSWQGALGPEAR N-terminal sequence was isolated from S. rugosoannulata, which represents the first protein isolated from the mushroom. The purification methods included (NH₄)₂SO₄ precipitation, ion exchange chromatography on CM-cellulose, Q-Sepharose, and SP-Sepharose, and gel- filtration on Superdex-75. The lectin was adsorbed on all three types of ion exchangers and was purified more than 450-fold. The lectin was stable below 70 °C (with half of the activity preserved at 80 °C), and in the presence of NaOH and HCl solutions up to a concentration of 12.5 mM and 25 mM, respectively. The hemagglutinating activity of SRL was inhibited by inulin. Cd²⁺ and Hg²⁺ ions strongly reduced the hemagglutinating activity at concentrations from 1.25 mM to 10 mM. SRL exhibited anti-proliferative activity toward both hepatoma Hep G2 cells and leukemia L1210 cells, with an IC₅₀ of 7 μM and 19 μM, respectively. The activity of HIV-1 reverse transcriptase could also be inhibited by SRL, with an IC₅₀ of 10 μM.