Effects of Ganoderma lucidum polysaccharide peptide ameliorating cyclophosphamide-induced immune dysfunctions based on metabolomics analysis

Abstract

Ganoderma lucidum polysaccharide peptide (GLPP) is one of the most abundant constituents of Ganoderma lucidum (G. lucidum), with a wide range of functional activities. The present study investigated the immunomodulatory effects of GLPP in cyclophosphamide (CTX)-induced immunosuppressive mice. The results showed that 100 mg/kg/day of GLPP administration significantly alleviated CTX-induced immune damage by improving immune organ indexes, earlap swelling rate, the index of carbon phagocytosis and clearance value, secretion of cytokines (TNF-α, IFN-γ, and IL-2), and immunoglobulin A(IgA) in the mice. Furthermore, ultra-performance liquid chromatography with mass/mass spectrometry (UPLC-MS/MS) was conducted to identify the metabolites, followed by biomarker and pathway analysis. The results showed that GLPP treatment alleviated CTX-induced alterations in the fecal metabolome profile, including arachidonic acid (AA), leukotriene D4 (LTD4), indole-3-ethanol, and formyltetrahydrofolate (CF), by reversing citric acid, malic acid, cortisol, and oleic acid. These results support the concept that GLPP exhibits immunomodulatory activity via the folate cycle, methionine cycle, TCA cycle, fatty acid biosynthesis and metabolism, glycerophospholipid metabolism, AA metabolism, and cAMP pathways. In conclusion, the results could be helpful to understand the use of GLPP to clarify the immunomodulatory mechanism and be used as immunostimulants to prevent CTX-induced side effects in the immune system.

Keywords: Ganoderma lucidum polysaccharide peptide; UPLC-MS/MS; cyclophosphamide-induced mice; fecal metabolome; immunomodulatory.

Figure 1

Effects of each group on the serum of immunoglobulin A (A), interleukin- 2 (B), interferon-γ (C), and the tumor necrosis factor-α (D) levels in CTX-induced mice. Data are expressed as mean ± SD (n = 7). ^#p < 0.05 and ^##p < 0.01 compared with the CK group; ^*p < 0.05 and ^**p < 0.01 compared with the CTX group.

Figure 2

Effects of each group on ear swelling index in CTX-induced mice. Data are expressed as mean ± SD (n = 7). ^#p < 0.05 and ^##p < 0.01 compared with the CK group; ^*p < 0.05 and ^**p < 0.01 compared with the CTX group.

Figure 3

Effects of each group on the index of carbon phagocytosis and clearance (α-valve). Data are expressed as mean ± SD (n = 7). ^#p < 0.05 and ^##p < 0.01 compared with the CK group; ^*p < 0.05 and ^**p < 0.01 compared with the CTX group.

Figure 4

Histopathological analysis of jejunum tissue of mice in each group at 200 × magnification.

Figure 5

The OPLS-DA score plot of the distinct metabolites. (A–D) are representations of the CTX group vs. the CK group, the CTX group vs. the L-GLPP group, the CTX group vs. the M-GLPP group, the CTX group vs. the H-GLPPgroup, respectively; (E, G–I) are representations of the LMS group vs. the CK group, the LMS group vs. the L-GLPP group, the LMS group vs. the M-GLPP group, the LMS group vs. the H-GLPP group, respectively; (F) is a representation of the CTX group vs. the LMS group.

Figure 6

Bubble plots of enrichment of differentially expressed metabolite in KEGG pathways. (A) KEGG pathway enrichment of the differences between the CK group and the CTX group; (B) KEGG pathway enrichment of the differences between the CTX group and the GLPP group; (C) KEGG pathway enrichment of the differences between the CTX group and the LMS group; The horizontal coordinate represents the rich factor of each pathway, and the vertical coordinate represents pathway name in KEGG, the size of the dot represents the number of enriched metabolites. The color of the dot represents p-value, the darker of red dot means higher of enrichment.