A novel heteropolysaccharide isolated from custard apple pulp and its immunomodulatory activity in mouse macrophages and dendritic cells.

In this study, a novel heteropolysaccharide (ASPA80-1) with an average molecular weight of 5.48 × 104 Da was isolated and structurally elucidated from custard apple pulp (Annona squamosa) through DEAE-cellulose, Sephadex G-100 and Sephacryl S-300 HR chromatography and spectral analysis. ASPA80-1 is a water-soluble polysaccharide and it is a polymer consisting of predominant amounts of (1 â†’ 3)-linked-L-arabinose (Ara) residues, small amounts of (1 â†’ 6)-linked-D-galactose (Gal), (1 â†’ 3,5)-linked-L-arabinose (Ara) residues and terminal linked-L-arabinose (Ara) residues, trace amount of (1 â†’ 4)-linked-D-glucose (Glc) residues and (1 â†’ 2)-linked-L-rhamnose (Rham) residues. ASPA80-1 showed significant effect on antigen-presenting cells (APCs) activation. On the one hand, ASPA80-1 activated RAW264.7 macrophage cells by inducing morphology change, enhancing phagocytic ability, increasing nitric oxide (NO) secretion and promoting expression of major histocompatibility complex class II (MHC II) and cluster of differentiation 86 (CD 86). On the other hand, ASPA80-1 promoted the maturation of dendritic cells (DCs) by inducing longer dendrites, decreasing phagocytic ability and increasing MHC II and CD86 expression. Furthermore, mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB) signaling pathways were activated after the intervention of ASPA80-1 on RAW264.7 cells or DCs. Thus, the novel heteropolysaccharide ASPA80-1 has the potential to be used as an immunoenhancing component in functional foods.

Characterization of a novel recombinant calcium-binding protein from Arca subcrenata and its anti-hepatoma activities in vitro and in vivo.

Previous studies demonstrated that ASP-3 was a novel calcium-binding protein from Arca subcrenata that effectively inhibited the proliferation of HepG2 cells. To further study the antitumor activity and mechanism of ASP-3, the cytotoxic effects of recombinant ASP-3 were evaluated in HepG2 cells. The results demonstrated that ASP-3 inhibited the proliferation of HepG2 cells by competitively binding to the EGF binding pocket of EGFR and inhibiting the JAK-STAT, RAS-RAF-MEK-ERK, and PI3K-Akt-mTOR signaling pathways mediated by EGFR. ASP-3 significantly inhibited tumor growth in a HepG2 cell subcutaneous xenograft nude mouse model, and its (25 mg/kg and 75 mg/kg) tumor inhibition rates were 46.92 % and 60.28 %, respectively. Furthermore, the crystal structure of ASP-3 was resolved at 1.4 Å. ASP-3 formed as a stable dimer and folded as an EF-Hand structure. ASP-3 stably bound to domain I and domain III of the EGFR extracellular region by using molecular docking and molecular dynamics simulation analysis. Compared with the endogenous ligand EGF, ASP-3 displayed a stronger interaction with EGFR. These experimental results indicated that recombinant ASP-3 possessed an effective anti-hepatoma effect. So, it might be a potential molecule for liver cancer therapy.

Isolation, structures and biological activities of medicinal glycoproteins from natural resources: A review.

In recent years, natural resources have proven to be tremendous sources of glycoproteins. As biological macromolecules, glycoproteins are essential to the growth and development of organisms, and have attracted increasing attention around the world. This review summarized and discussed the development of glycoproteins from natural resources, including isolation methods, purification processes, structural features and biological activities. Generally, the vast majority of glycoproteins can be isolated by hot water extraction followed by purification through gel filtration chromatography. Combined with component analysis, the physicochemical properties of glycoproteins are studied by using several spectroscopic techniques such as ultraviolet-visible (UV-visible), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR). Moreover, natural glycoproteins possess various remarkable biological activities, including anti-tumor, anti-oxidant, anti-coagulant and anti-microbial activities. The content of this review will provide a theoretical basis for the research on related glycoproteins and give a perspective on the use of these medical resources.

Novel plant-derived exosome-like nanovesicles from Catharanthus roseus: preparation, characterization, and immunostimulatory effect via TNF-α/NF-κB/PU.1 axis.

BACKGROUND: Plant-derived exosomes-like nanovesicles (PDENs) have been found to be advantageous in disease treatment and drug delivery, but research on their biogenesis, compositional analysis, and key marker proteins is still in its infancy, which limits the standardized production of PDENs. Efficient preparation of PDENs continues to be a major challenge. RESULTS: Novel PDENs-based chemotherapeutic immune modulators, Catharanthus roseus (L.) Don leaves-derived exosome-like nanovesicles (CLDENs) were isolated from apoplastic fluid. CLDENs were membrane structured vesicles with a particle size of 75.51 ± 10.19 nm and a surface charge of -21.8 mV. CLDENs exhibited excellent stability, tolerating multiple enzymatic digestions, resisting extreme pH environments, and remaining stable in the gastrointestinal simulating fluid. Biodistribution experiments showed that CLDENs could be internalized by immune cells, and targeted at immune organs after intraperitoneal injection. The lipidomic analysis revealed CLDENs' special lipid composition, which contained 36.5% ether-phospholipids. Differential proteomics supported the origin of CLDENs in multivesicular bodies, and six marker proteins of CLDENs were identified for the first time. 60 ~ 240 µg/ml of CLDENs promoted the polarization and phagocytosis of macrophages as well as lymphocyte proliferation in vitro. Administration of 20 mg/kg and 60 mg/kg of CLDENs alleviated white blood cell reduction and bone marrow cell cycle arrest in immunosuppressive mice induced by cyclophosphamide. CLDENs strongly stimulated the secretion of TNF-α, activated NF-κB signal pathway and increased the expression of the hematopoietic function-related transcription factor PU.1 both in vitro and in vivo. To ensure a steady supply of CLDENs, plant cell culture systems of C. roseus were established to provide CLDENs-like nanovesicles which had similar physical properties and biological activities. Gram-level nanovesicles were successfully obtained from the culture medium, and the yield was three times as high as the original. CONCLUSIONS: Our research supports the use of CLDENs as a nano-biomaterial with excellent stability and biocompatibility, and for post-chemotherapy immune adjuvant therapy applications.

The ß-catenin-LINC00183-miR-371b-5p-Smad2/LEF1 axis promotes adult T-cell lymphoblastic lymphoma progression and chemoresistance.

BACKGROUND: High-intensity chemotherapy regimens are often used in adult T-cell lymphoblastic lymphoma (T-LBL) patients. Nevertheless, the response rate remains unsatisfactory due to emergence of chemoresistance. Growing evidence has shown that long non-coding RNAs (lncRNAs) are involved in tumor progression and chemoresistance. Herein, we investigated the potential role of lncRNAs in T-LBLs. METHODS: RNAseq was used to screen and identify candidate lncRNAs associated with T-LBL progression and chemoresistance. Luciferase reporter assay was used to examine the binding of miR-371b-5p to the 3'UTR of Smad2 and LEF1, and the binding of TCF-4/LEF1 to the promoter of LINC00183. Chromatin immunoprecipitation assay was undertaken to analyze the connection between LEF1 and the LINC00183 promoter region. RNA immunoprecipitation assays were used to explore the mechanism whereby LINC00183 regulated miR-371b-5p. MTT and flow cytometry assays were used to measure apoptosis of T-LBL cells. RESULTS: LINC00183 was upregulated in T-LBL progression and chemoresistant tissues in both the Sun Yat-sen University Cancer Center dataset and the First Affiliated Hospital of Anhui Medical University dataset. High expression of LINC00183 was correlated with poorer overall survival and progression-free survival of T-LBL patients compared to those with low expression of LINC00183. Furthermore, miR-371b-5p was negatively regulated by LINC00183. In vivo and in vitro assays showed that LINC00183-mediated T-LBL chemoresistance depended on miR-371b-5p expression. The direct binding of miR-371b-5p to Smad2 and LEF1 was verified by luciferase assays. It was shown that TCF4/LEF1 could bind to the LINC00183 promoter site and increase its transcript level. Downregulation of miR-371b-5p led to increased expression of Smad2/LEF1, and in turn increased LINC00183 expression. Additionally, phospho-Smad2 promotes nuclear translocation of ß-catenin, LINC00183 downregulation decreased chemoresistance induced by ß-catenin and TGF-ß1 in T-LBL cells. CONCLUSION: We unraveled a ß-catenin-LINC00183-miR-371b-5p-Smad2/LEF1 feedback loop that promotes T-LBL progression and chemoresistance, indicating that LINC00183 may serve as a potential therapeutic target in T-LBLs.

Establishment of recombinant Catharanthus roseus stem cells stably overexpressing ORCA4 for terpenoid indole alkaloids biosynthesis.

Catharanthus roseus is a perennial herb of the Apocynaceae family, from which about 200 kinds of alkaloids have been characterized. Most alkaloids from C. roseus are terpenoid indole alkaloids (TIAs), such as vinblastine and vincristine, which are widely used in the clinic for their good antitumor activity. However, they were only biosynthesized in C. roseus, and their content in C. roseus is extremely low. The access to these valuable compounds is by plant extraction or chemical semisynthesis from their precursors catharanthine and vindoline. Since catharanthine and vindoline are also obtained from C. roseus, the supply of vinblastine and vincristine makes it difficult to meet market demands. Therefore, how to improve the yield of TIAs is an attractive issue. In this study, we compared the regulatory effect of two critical transcription factors, octadecanoid-derivative responsive Catharanthus AP2-domain protein 3 (ORCA3) and octadecanoid-derivative responsive Catharanthus AP2-domain protein 4 (ORCA4), on the biosynthesis of TIAs in C. roseus. The results showed that overexpressing both two transcription factors could increase the accumulation of TIAs. The effect was more significant when ORCA4 was overexpressed. To acquire C. roseus TIAs on a continuous and consistent basis, we then created and acquired C. roseus stem cells stably overexpressing ORCA4. This is the first time a recombinant C. roseus stem cell system with stable ORCA4 overexpression has been developed, which not only provides new ideas for future research in this area but also breaches new life into the industrial application of using plant cell culture to obtain natural products.

Characterization of a novel polysaccharide from Arca subcrenata and its immunoregulatory activities in vitro and in vivo.

Arca subcrenata is an economical edible shellfish. A novel water-soluble α-D-glucan (ASPG-1) with a molecular weight of 2.56 × 106 Da was purified and characterized from A. subcrenata. Its structure was characterized as a repeating unit consisting of α-D-Glcp, (1 → 6)-α-D-Glcp and (1 → 4,6)-α-D-Glcp. ASPG-1 exerted potent immunoregulatory activity by promoting the viability of splenic lymphocytes. Moreover, it enhanced pinocytic capacity, and promoted the secretion of NO and cytokines in RAW264.7 cells. The immunomodulatory mechanism of ASPG-1 involved the activation of the TLR4-MAPK/Akt-NF-κB signaling pathway. ASPG-1 inhibited tumor growth in 4T1 breast cancer mice and its combination with doxorubicin increased antitumor efficacy. The ASPG-1 combination with DOX-treated group (64.8%) showed an improved tumor inhibition rate compared to that of the DOX-treated group (53.3%). The antitumor mechanism of ASPG-1 may involve an enhancement of the immune response of mice to tumors. These results indicated that ASPG-1 could be developed as a potential adjuvant in tumor immunotherapy.

Correction: Efficiently increasing the radiative rate of TADF material with metal coordination.

Correction for 'Efficiently increasing the radiative rate of TADF material with metal coordination' by Xian-Bao Cai et al., Chem. Commun., 2022, 58, 8970-8973, https://doi.org/10.1039/D2CC02930H.

Arteannuin B Enhances the Effectiveness of Cisplatin in Non-Small Cell Lung Cancer by Regulating Connexin 43 and MAPK Pathway.

Cisplatin (DDP)-based chemotherapy is the first-line regimen for advanced non-small cell lung cancer (NSCLC) patients. However, advanced NSCLC patients may have innate resistance to DDP or develop resistance during DDP treatment. We investigated a natural compound, arteannuin B (Art B), for its potential effects on DDP resistance in NSCLC. Art B was isolated from Artemisia annua by chromatographic purification and spectral elucidation. The activities of Art B on DDP-mediated effects were examined using in vitro and in vivo assays. We observed significant correlations in T stage, clinical stage, chemotherapy resistance and poor survival of NSCLC patients with low Cx43 expression. Art B enhanced the effectiveness of cisplatin by increasing Cx43 expression in normal and DDP-resistant NSCLC cells. Art B also increased DDP uptake through up-regulating Cx43. The combination of DDP and Art B showed better therapeutic effect than individual treatments both in vitro and in vivo. Art B increased intracellular Fe[Formula: see text] level, promoted calcium influx, and activated gap junction and MAPK pathways, which might contribute to Art B-mediated effects. Art B may serve as a new drug candidate to enhance the antitumor effect of DDP on NSCLC.

Efficiently increasing the radiative rate of TADF material with metal coordination.

Herein, a simple and straightforward method to reduce dramatically the lifetime of a pure organic thermally activated delayed fluorescence (TADF) material VIA metal coordination is demonstrated. We designed a mononuclear silver complex [Ag(PPh2CH3)(TCzBN-PyPz)]BF4 (1) with a new emissive TCzBN-PyPz ligand. Even though the ligand and the metal complex have very similar emissive efficiencies and maximal peaks, over three orders of magnitude shorter lifetime of 0.59 µs for the complex than 2074 µs for ligand were obtained. Compared to other methods, the present protocol seems to be simple and highly effective.

Structural characterization and immunoregulatory activity of a novel acidic polysaccharide from Scapharca subcrenata.

A novel acidic polysaccharide named SSPA50-1 was isolated from Scapharca subcrenata using a simulated gastric fluid extraction method. SSPA50-1 is a heteropolysaccharide with an average molecular weight of 44.7 kDa that is composed of galacturonic acid, glucose, galactose, mannose, ribose, rhamnose, fucose, xylose and arabinose at a molar ratio of 1.00:5.40:9.04:3.10:1.59:4.01:2.10:2.21:2.28. The structural characterization based on the methylation and 1D/2D NMR analyses indicated that SSPA50-1 is composed of →3)-ß-L-Rhap-(1→, →3)-ß-L-2-O-Me-Fucp-(1→, →2)-α-D-Xylp-(1→, →5)-α-L-Araf-(1→, →3)-ß-D-Galp-(1→, →6)-α-D-Glcp-(1→, →3,4)-ß-D-Manp-(1→, →3,4)-ß-D-Galp-(1→, ß-D-Ribf-(1→, α-D-Glcp-(1→, and α-D-GalAp6Me-(1→. Furthermore, SSPA50-1 possessed potent immunoregulatory activity by enhancing the phagocytosis and NO, iNOS, TNF-α and IL-6 secretion capacity of RAW264.7 cells. Otherwise, SSPA50-1 significantly promoted the proliferation of splenic lymphocytes and RAW264.7 macrophages. These results indicated that SSPA50-1 could be developed as a potential ingredient for immunostimulatory agents.

A highly branched α-d-glucan facilitates antitumor immunity by reducing cancer cell CXCL5 expression.

Tumor immunotherapy has emerged as a major pillar of anticancer therapeutic strategies. Natural polysaccharides, known for their strong immunomodulatory activities with relatively low cost and toxicity, are becoming promising prospects for cancer immunotherapy. In this study, we investigated the antitumor mechanism of JNY2PW, a highly branched α-d-glucan previously purified from the traditional marine Chinese medicine Arca inflata. JNY2PW was shown to enhance the sensitivity of tumor cells to co-culture macrophage supernatants by decreasing cancer cell CXCL5 expression. Furthermore, JNY2PW exerted antitumor effects without obvious toxic side effects in tumor-bearing mice by triggering the Akt/mTOR and ERK/GSK3ß/ß-catenin pathways and attenuating expression of CXCL5 in cancer cells. Remarkably, JNY2PW reduced tumor proliferation and dampened CXCL5 expression in tumor cells overexpressing CXCL5 both in vitro and in vivo. Additionally, JNY2PW blocked epithelial-mesenchymal transition (EMT) in both CXCL5-overexpressing and wild type tumor cells. Our data therefore uncovered a previously unrecognized antitumor mechanism for JNY2PW, suggesting that JNY2PW is a promising adjuvant as an immunomodulator for cancer immunotherapy.

A Novel Peptide Derived from Arca inflata Induces Apoptosis in Colorectal Cancer Cells through Mitochondria and the p38 MAPK Pathway.

Colorectal carcinoma (CRC) is one of the major causes of cancer-related incidence and deaths. Here, we identified a novel antitumor peptide, P6, with a molecular weight of 2794.8 Da from a marine Chinese medicine, Arca inflata Reeve. The full amino acid sequence and secondary structure of P6 were determined by tandem mass de novo sequencing and circular dichroism spectroscopy, respectively. P6 markedly inhibited cell proliferation and colony formation, and induced apoptosis in CRC cells. Mechanistically, transcriptomics analysis and a serial functional evaluation showed that P6 induced colon cancer cell apoptosis through the activation of the p38-MAPK signaling pathway. Moreover, it was demonstrated that P6 exhibited antitumor effects in a tumor xenograft model, and induced cell cycle arrest in CRC cells in a concentration-dependent mode. These findings provide the first line of indication that P6 could be a potential therapeutic agent for CRC treatment.

Dihydroartemisinin is potential therapeutics for treating late-stage CRC by targeting the elevated c-Myc level.

Currently, no frontline treatment is effective for the late-stage colorectal cancer (CRC). Understanding the molecular differences in different stages of CRC can help us to identify the critical therapeutic targets for designing therapeutic strategy. Our data show that c-Myc protein is highly expressed in late-stage CRC when compared with early-stage CRC in both clinical samples and in cell lines representing different cancer stages. Given that c-Myc is a well-known oncogenic driver in CRC, its high expression in the late-stage CRC may represent a critical therapeutic target for treating the cancer. Dihydroartemisinin treatment significantly increases c-Myc protein degradation and hence reduces its expression in CRC. The treatment also reduces CRC cell viability. Interestingly, dihydroartemisinin exhibits a more potent growth-inhibitory effect in late-stage CRC than the early-stage CRC. The treatment also possesses potent growth-inhibitory effects in mouse models bearing c-Myc-overexpressed CRC. The reduced c-Myc level and its reduced transcriptional activity reduce the expressions of acetyl-CoA carboxylase, fatty acid synthase, carnitine-palmitoyltransferase-1, and medium-chain acyl-CoA dehydrogenase in the cancer cells. Lipidomics study also shows that dihydroartemisinin treatment changes the metabolic phenotypes in CRC, reduces oxygen consumption, respiration, and ATP production, hence reduces the cell proliferation and induces apoptosis. Our study provides strong pharmacological evidence to support the translation of dihydroartemisinin for the treatment of late-stage CRC by targeting c-Myc.

Mining of the Catharanthus roseus Genome Leads to Identification of a Biosynthetic Gene Cluster for Fungicidal Sesquiterpenes.

Characterization of cryptic biosynthetic gene clusters (BGCs) from microbial genomes has been proven to be a powerful approach to the discovery of new natural products. However, such a genome mining approach to the discovery of bioactive plant metabolites has been muted. The plant BGCs characterized to date encode pathways for antibiotics important in plant defense against microbial pathogens, providing a means to discover such phytoalexins by mining plant genomes. Here is reported the discovery and characterization of a minimal BGC from the medicinal plant Catharanthus roseus, consisting of an adjacent pair of genes encoding a terpene synthase (CrTPS18) and cytochrome P450 (CYP71D349). These two enzymes act sequentially, with CrTPS18 acting as a sesquiterpene synthase, producing 5-epi-jinkoheremol (1), which CYP71D349 further hydroxylates to debneyol (2). Infection studies with maize revealed that 1 and 2 exhibit more potent fungicidal activity than validamycin. Accordingly, this study demonstrates that characterization of such cryptic plant BGCs is a promising strategy for the discovery of potential agrochemical leads. Moreover, despite the observed absence of 1 and 2 in C. roseus, the observed transcriptional regulation is consistent with their differential fungicidal activity, suggesting that such conditional coexpression may be sufficient to drive BGC assembly in plants.

A new GlcNAc-containing polysaccharide from Morchella importuna fruiting bodies: Structural characterization and immunomodulatory activities in vitro and in vivo.

This study investigated the purification and characterization of a new immunomodulatory GlcNAc-containing polysaccharide (MIPB70-1) from Morchella importuna with molecular weights of 20.6 kDa. Structural analysis indicated that MIPB70-1 was composed of GlcNAc:Gal:Glc:Man with molar ratios of 1.00:7.16:5.54:5.61, and its primary structure was characterized as a repeating unit consisting of →6)-α-D-Glcp-(1→, α-D-GlcpNAc-(1→, α-D-Galp-(1→, ß-D-Glcp-(1→, →6)-α-D-Manp-(1→, →4)-α-D-GlcpNAc-(1→, →4)-ß-D-Glcp-(1→, →3,6)-α-D-Manp-(1→, →2)-α-D-Galp-(1→, →2,3,6)-α-D-Manp-(1→. Immunological assays indicated that MIPB70-1 enhanced the phagocytic function and promoted the secretion of nitric oxide (NO) as well as cytokines through targeting Toll-like receptor 4 (TLR4) on macrophage membrane and activating the downstream signaling pathways in RAW 264.7 cells. MIPB70-1 regulated mouse immunity to counteract the immune damage caused by the chemotherapy drug cyclophosphamide (CTX) in vivo. Furthermore, MIPB70-1 enhanced the anti-tumor activity of doxorubicin (DOX) and inhibited the growth of tumors, by immunomodulation in the orthotopic murine model of 4T1 breast cancer. These results demonstrate the potential of this GlcNAc-containing polysaccharide as an immune enhancer.

Development of Arteannuin B Sustained-Release Microspheres for Anti-Tumor Therapy by Integrated Experimental and Molecular Modeling Approaches.

Arteannuin B (AB) has been found to demonstrate obvious anti-tumor activity. However, AB is not available for clinical use due to its very low solubility and very short half-life. This study aimed to develop AB long sustained-release microspheres (ABMs) to improve the feasibility of clinical applications. Firstly, AB-polylactic-co-glycolic acid (PLGA) microspheres were prepared by a single emulsification method. In vitro characterization studies showed that ABMs had a low burst release and stable in vitro release for up to one week. The particle size of microspheres was 69.10 µm (D50). The drug loading is 37.8%, and the encapsulation rate is 85%. Moreover, molecular dynamics modeling was firstly used to simulate the preparation process of microspheres, which clearly indicated the molecular image of microspheres and provided in-depth insights for understanding several key preparation parameters. Next, in vivo pharmacokinetics (PK) study was carried out to evaluate its sustained release effect in Sprague-Dawley (SD) rats. Subsequently, the methyl thiazolyl tetrazolium (MTT) method with human lung cancer cells (A549) was used to evaluate the in vitro efficacy of ABMs, which showed the IC50 of ABMs (3.82 µM) to be lower than that of AB (16.03 µM) at day four. Finally, in vivo anti-tumor activity and basic toxicity studies were performed on BALB/c nude mice by subcutaneous injection once a week, four times in total. The relative tumor proliferation rate T/C of AMBs was lower than 40% and lasted for 21 days after administration. The organ index, organ staining, and tumor cell staining indicated the excellent safety of ABMs than Cis-platinum. In summary, the ABMs were successfully developed and evaluated with a low burst release and a stable release within a week. Molecular dynamics modeling was firstly applied to investigate the molecular mechanism of the microsphere preparation. Moreover, the ABMs possess excellent in vitro and in vivo anti-tumor activity and low toxicity, showing great potential for clinical applications.

Structural characterization and immunomodulatory mechanisms of two novel glucans from Morchella importuna fruiting bodies.

Two novel glucans named MIPB50-W and MIPB50-S-1 were obtained from edible Morchella importuna with molecular weights (Mw) of 939.2 kDa and 444.5 kDa, respectively. MIPB50-W has a backbone of α-(1 → 4)-d-glucan, which was substituted at O-6 position by α-d-Glcp-(1→. Moreover, MIPB50-S-1 has a backbone of α-(1 → 4)-d-glucan, which was substituted at O-6 position by α-d-Glcp-(1 → 6)-α-d-Glcp-(1→. This is the first report about glucan found in Morchella mushrooms. Furthermore, MIPB50-W and MIPB50-S-1 strengthened the phagocytosis function and the promoted secretion of interleukins (IL)-6/tumor necrosis factor-alpha (TNF-α) and nitric oxide (NO), which induced the activation of Toll-like receptor 2 (TLR2), TLR4 as well as mitogen activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) pathways. Interestingly, MIPB50-S-1 performed the better immunomodulatory activity than that of MIPB50-W in almost all tests. Therefore, MIPB50-W and MIPB50-S-1 are potential immune-enhancing components of functional foods.

Purification and characterization of a novel mixed-linkage α,ß-d-glucan from Arca subcrenata and its immunoregulatory activity.

Arca subcrenata Lischke is a seafood with high nutritional value. In this study, we purified and characterized a novel water-soluble polysaccharide (ASPG-2) from Arca subcrenata with significant immunoregulatory effects and no apparent cell toxicity. ASPG-2 is a class of mixed-linkage α,ß-d-glucan backbones with α-linked side chains with a molecular weight of 4.39 × 105 Da. Its structure was characterized as a repeating unit consisting of (1 → 3)-ß-d-Glcp, (1 → 4)-α-d-Glcp, (1 → 4,6)-α-d-Glcp and (1 → 6)-α-d-Glcp. Using mouse RAW264.7 macrophages, we demonstrated that ASPG-2 exerted marked immunoregulatory effects by promoting the secretion of NO and increasing the phagocytosis of RAW264.7 cells in vitro. Moreover, flow cytometry analysis of the expression of the cell surface molecule CD86 revealed that ASPG-2 could polarize RAW264.7 cells into the M1 type. The immunomodulatory mechanism of ASPG-2 in macrophages was associated with the activation of the TLR4-MAPK/Akt-NF-κB signalling pathways. These results indicated that ASPG-2 might be researched and developed as a potential immunomodulatory agent or health product from marine organisms.

The study of antiviral drugs targeting SARS-CoV-2 nucleocapsid and spike proteins through large-scale compound repurposing.

Contributing to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) clinical treatment, a drug library encompassing approximately 3,142 clinical-stage or FDA-approved small molecules is profiled to identify the candidate therapeutic inhibitors targeting nucleocapsid protein (N) and spike protein (S) of SARS-CoV-2. 16 screened candidates with higher binding affinity are evaluated via virtual screening. Comparing to those under trial/temporarily used antivirus drugs (i.e., umifenovir, lopinavir), ceftriaxone, cefotaxime, and cefuroxime show higher binding affinities to the N-terminal domain of N protein (N-NTD), C-terminal domain of N protein (N-CTD), and receptor-binding domain of S protein (S-RBD). Cefotaxime and cefuroxime have high binding affinities towards S-RBD with angiotensin-converting enzyme 2 (ACE2) complex via influence the critical interface sites at the interface of S-RBD (Arg403, Tyr453, Trp495, Gly496, Phe497, Asn501and Tyr505) and ACE2 (Asn33, His34, Glu37, Asp38, Lys353, Ala386, Ala387, Gln388, Pro389, Phe390 and Arg393) complex.