Therapeutic effects of lentinan on inflammatory bowel disease and colitis-associated cancer

Synthesis of gold-silver nanoalloys under microwave-assisted irradiation by deposition of silver on gold nanoclusters/triple helix glucan and antifungal activity

Polysaccharides are ideal green synthetic raw materials to improve the biocompatibility of metal nanoparticles. However, polysaccharides generally have weak reducibilities, being challenging supports for the direct preparation of Ag nanoparticles. In this work, gold nanoclusters were prepared using a triple helix glucan (Lentinan) via microwave-assisted synthesis and subsequently employed as seeds for the synthesis of a series of Ag-Au alloy nanoparticles (Ag-AuNPs). The results showed that gold nanoclusters can remarkably speed up the preparation of Ag-AuNPs without the addition of any other chemicals. The particle size of Ag-AuNPs increased at increasing Ag contents in the alloy. Results of UV-vis, transmission electron microscope (TEM) and inductively coupled plasma mass spectrometry (ICP-MS) suggested that Ag⁺ was quickly reduced to irregular silver nanoparticles (with gold nanoparticles as seeds), then gradually form more regular nano-alloys. Additionally, X-ray diffraction (XRD) and zeta potential results suggested that Ag-AuNPs could entrap the hydrophobic cavity of triple helix polysaccharides during the renaturation process. The nanocomposites exhibited good antifungal activity and low cytotoxicity to RAW264.7, Hela and LO2 cell lines in vitro.

MiR-27a-3p downregulation contributes to the development of occlusive bronchiolitis

The only effective clinical treatment for many end-stage lung diseases is lung transplantation. However, chronic rejection of transplanted lung affects the long-term efficacy of lung transplantation to a large extent, thereby limiting the clinical application of lung transplantation. Occlusive bronchiolitis (OB) is a major cause of chronic functional loss of the transplanted lung. However, the OB pathogenesis remains unclear. Therefore, studying the OB pathogenesis and finding effective intervention methods are highly important. This study analyzed changes in the expression profile of microRNAs and transcription factors in mice with OB after orthotopic tracheal transplantation. miR-27a-3p was upregulated in lung tissue 20 days after transplantation. Transcription factor microarray analysis revealed that Smad3 was significantly downregulated. A miRNA-mRNA interaction network was constructed, and specific regulatory effects of miR-27a-3p on Smad3 were found. Smad3 was strongly associated with tumorigenesis and organ fibrosis. Compared with the control group, miR-27a-3p inhibited the epithelial-mesenchymal transformation (EMT) of lung epithelial cells. In addition, miR-27a-3p inhibition promoted the invasion and migration of lung epithelial cells. Dual luciferase reporter gene assay showed that miR-27a-3p can regulate the promoter activity of Smad3. MiR-27a-3p also inhibited the expression of inflammatory cytokines. Western blot results showed that miR-27a-3p can upregulate the E-cadherin expression and downregulate the expression of vimentin, fibronectin, and α-SMA. By studying the OB pathogenesis, we found that inhibition or alteration of the occurrence of EMT may reduce the proportion of chronic rejection of lung transplantation. MiR-27a-3p may also be developed as a new drug for the OB therapy. This finding will provide many possibilities for OB treatment and improve the prognosis of patients with OB.

Structure and Immunomodulatory Activity of Microparticulate Mushroom Sclerotial β-Glucan Prepared from Polyporus rhinocerus

In this study, an immunologically active novel microparticulate mushroom β-glucan (PRA-1p) was prepared using an alkali-soluble glucan PRA-1 by an emulsification and cross-linking method. PRA-1 was a hyperbranched (1→3),(1→6)-β-d-glucan with a degree of branching of 0.89, isolated from the sclerotia of Polyporus rhinocerus. PRA-1 had a rod-like conformation, while PRA-1p exhibited a monodisperse and homogeneous spherical conformation with a diameter ranging from 0.3 to 2.0 μm in water. PRA-1p significantly induced nitric oxide and reactive oxygen species production as well as morphological changes of murine macrophages (RAW 264.7 cells) and upregulated their phagocytic activity. Furthermore, PRA-1p treatment markedly enhanced the secretion of cytokines, including cutaneous T cell-attracting chemokine 27, granulocyte-colony-stimulating factor, monocyte chemoattractant protein 1, macrophage inflammatory protein 1α, macrophage inflammatory protein 2, regulated on activation, normal T cell expressed and secreted, soluble tumor necrosis factor receptor 1, and tissue inhibitors of metalloproteinases. Activation of RAW 264.7 cells triggered by PRA-1p was associated with activation of inducible nitric oxide synthase, nuclear factor κB, extracellular signal-regulated kinase, and protein kinase B. This work suggests that novel PRA-1p derived from the mushroom sclerotia of P. rhinocerus has potential application as an immunostimulatory agent.

P2X7 receptor: A potential therapeutic target for autoimmune diseases

P2X7 receptor (P2X7R), a distinct ligand-gated ion channel, is a member of purinergic type 2 receptor family with ubiquitous expression in human body. Previous studies have revealed a pivotal role of P2X7R in innate and adaptive immunity. Once activated, it will meditate some vital cascaded responses including the assembly of nucleotide-binding domain (NOD) like receptor protein 3 (NLRP3) inflammasome, non-classical secretion of IL-1β, modulation of cytokine-independent pathways in inflammation such as P2X7R- transglutaminase-2 (TG2) and P2X7R-cathepsin pathway, activation and regulation of T cells, etc. In fact, above responses have been identified to be involved in the development of autoimmunity, specifically, the NLRP3 inflammasome could promote inflammation in massive autoimmune diseases and TG2, as well as cathepsin may contribute to joint destruction and degeneration in inflammatory arthritis. Recently, numerous evidences further suggested the significance of P2X7R in the pathogenesis of autoimmune diseases, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), inflammatory bowel disease (IBD), multiple sclerosis (MS), etc. In this review, we will succinctly discuss the biological characteristics and summarize the recent progress of the involvement of P2X7R in the development and pathogenesis of autoimmune diseases, as well as its clinical implications and therapeutic potential.

Inhibition of myeloid differentiation 1 specifically in colon with antisense oligonucleotide exacerbates dextran sodium sulfate-induced colitis

Myeloid differentiation 1 (MD-1), also known as lymphocyte antigen 86 (Ly86), is a soluble protein homologous to MD-2 and forms a complex with radioprotective 105 (RP105). RP105/MD-1 complex negatively regulates toll-like receptor 4 (TLR4) signaling and is involved in several immune disorders. However, the precise role of MD-1 in inflammatory bowel diseases (IBD) remains poorly understood. To further investigate the involvement of MD-1 in IBD, we inhibited MD-1 in colon with antisense oligonucleotide (AS-ODN) and assessed the effect of MD-1 inhibition on dextran sodium sulfate (DSS)-induced colitis. We discovered that MD-1 protein expression was remarkably decreased in both patients with ulcerative colitis and mice with DSS-induced colitis. For the first time, we showed that oral administration of MD-1 AS-ODN to mice significantly suppressed the MD-1 protein levels in colon rather than systemic tissues. Subsequently, we found that MD-1 AS-ODN treated mice were more susceptible to DSS-induced colitis based on loss of body weight, colon length, histological scores, and disease activity index. MD-1 inhibition also significantly enhanced inflammatory cytokines production such as IL-6 and IL-1β in colons. Finally, mice treated with MD-1 AS-ODN exhibited increased messenger RNA levels of TLR4 and MyD88 after DSS exposure and showed enhanced nuclear factor (NF)-κB activation compared with the control. Taken together, specifically suppression of MD-1 in colon tissues with AS-ODN exacerbates DSS-induced experimental colitis in mice, which is possibly related to activation of TLR4/NF-κB signaling.

Therapeutic effects of lentinan on inflammatory bowel disease and colitis-associated cancer

In this study, we investigated the therapeutic potential of lentinan in mouse models of inflammatory bowel disease (IBD) and colitis-associated cancer (CAC). Lentinan decreased the disease activity index and macroscopic and microscopic colon tissue damage in dextran sulphate sodium (DSS)-induced or TNBS-induced models of colitis. High-dose lentinan was more effective than salicylazosulfapyridine in the mouse models of colitis. Lentinan decreased the number of tumours, inflammatory cell infiltration, atypical hyperplasia and nuclear atypia in azoxymethane/DSS-induced CAC model. It also decreased the expression of pro-inflammatory cytokines, such as IL-13 and CD30L, in IBD and CAC model mice possibly by inhibiting Toll-like receptor 4 (TLR4)/NF-κB signalling and the expression of colon cancer markers, such as carcinoembryonic antigen, cytokeratin 8, CK18 and p53, in CAC model mice. In addition, lentinan restored the intestinal bacterial microbiotal community structure in IBD model mice. Thus, it shows therapeutic potential in IBD and CAC model mice possibly by inhibiting TLR4/NF-κB signalling-mediated inflammatory responses and disruption of the intestinal microbiotal structure.