Immune-Enhancing Effect of Submerged Culture of Ceriporia lacerata Mycelia on Cyclophosphamide-Induced Immunosuppressed Mice and the Underlying Mechanisms in Macrophages

Abstract

The white-rot fungi Ceriporia lacerata is used in bioremediation, such as lignocellulose degradation, in nature. Submerged cultures and extracts of C. lacerata mycelia (CLM) have been reported to contain various active ingredients, including β-glucan and extracellular polysaccharides, and to exert anti-diabetogenic properties in mice and cell lines. However, the immunostimulatory effects have not yet been reported. This study aimed to identify the immunomodulatory effects, and underlying mechanisms thereof, of submerged cultures of CLM using RAW264.7 macrophages and cyclophosphamide (CTX)-induced immunosuppression in mice. Compared to CTX-induced immunosuppressed mice, the spleen and thymus indexes in mice orally administered CLM were significantly increased; body weight loss was alleviated; and natural killer (NK) cytotoxicity, lymphocyte proliferation, and cytokine (tumor necrosis factor [TNF]-α, interferon [IFN]-γ, and interleukin [IL]-2) production were elevated in the serum. In RAW264.7 macrophages, treatment with CLM induced phagocytic activity, increased the production of nitric oxide (NO), and promoted mRNA expression of the immunomodulatory cytokines TNF-α, IFN-γ, IL-1β, IL-6, IL-10, and IL-12. In addition, CLM increased the inducible NO synthase (iNOS) concentration in macrophages, similar to lipopolysaccharide (LPS) stimulation. Mechanistic studies showed that CLM induced the activation of the NF-κB, PI3k/Akt, ERK1/2, and JNK1/2 pathways. Moreover, the phosphorylation of NF-κB and IκB induced by CLM in RAW264.7 cells was suppressed by specific MAPKs and PI3K inhibitors. Further experiments with a TLR4 inhibitor demonstrated that the production of TNF-α, IL-1β, and IL-6 induced by CLM was decreased after TLR4 was blocked. Overall, CLM protected against CTX-induced adverse reactions by enhancing humoral and cellular immune functions, and has potential as an immunomodulatory agent.

Immune-Enhancing Effects of Co-treatment With Kalopanax pictus Nakai Bark and Nelumbo nucifera Gaertner Leaf Extract in a Cyclophosphamide-Induced Immunosuppressed Rat Model

“…In addition, NN exerts anti-inflammatory effects on LPS-stimulated RAW 264.7 macrophages through inhibition of NF-κB and MAPK pathways ( 44 – 48 ). Similar to a previous study ( 35 , 40 – 48 ), our results showed that KPNN increased the p-NF-κB and p-ERK in RAW 264.7 cells. These findings are thought to be because of the positive role of KPNN in activating cytokines in Th1 cells, stimulating immune factors in the body, and increasing the activity of NK cells ( 49 ).…”

“…LPS-induced activation of macrophages produces pro-inflammatory cytokines (IL-1, TNF-α, IL-6, and IFN-γ), leading to the activation of phospholipase A2, which produces lipid metabolites of arachidonic acid, such as prostaglandins, and NO. Macrophages also induce MAPK-dependent phosphorylation, thereby activating multiple transcription factors ( 32 – 35 ). LPS upregulates TNF-α and iNOS expression by activating multiple transcription factors and inducing MAPK-dependent phosphorylation.…”

“…LPS upregulates TNF-α and iNOS expression by activating multiple transcription factors and inducing MAPK-dependent phosphorylation. NF-κB is also a major activator of TNF-α production by macrophages ( 35 ). Stimulation of splenocyte viability may consequently increase the secretion of cytokines, potentially explaining the observed immune-enhancing and anti-cancer capacity ( 36 ).…”

“…The different cytokines secreted by T cell subtypes, Th1 and Th2, are important determinants of cell function. Th1 and Th2 cells are mainly involved in cell-mediated and humoral responses, respectively, and promote the secretion of IL-2, TNF-α, and IFN-γ, and IL-4, IL-6, and IL-10, respectively ( 11 , 12 , 35 ). TNF-α is produced by T cells, B cells, NK cells, and macrophages and regulates inflammation and host defense by inhibiting bacterial infection and acute stress ( 62 ).…”

“…TNF-α is produced by T cells, B cells, NK cells, and macrophages and regulates inflammation and host defense by inhibiting bacterial infection and acute stress ( 62 ). IFN-γ promotes Th1 cell differentiation and stimulates B cells to promote Ig production, leading to antibody immunoreactivity ( 35 ). Our study on the mouse RAW 264.7 macrophages suggested that KPNN might be involved in the production of macrophage-associated cytokines (TNF-α, IFN-γ, IL-1β, IL-6, and IL-12) via MAPK and NF-κB signaling.…”