In this study, the structure and pro-inflammatory activities of water-soluble wheat bran polysaccharides (WBP) were evaluated. WBP were heteropolysaccharides consisting 60.34% arabinoxylan as the main component and 31.80% mannose residues characterized with the instrumental analyses. The result of cellular experiment displayed that WBP had significant pro-inflammatory activities by increasing the concentration of nitric oxide (NO) and up-regulating the inflammatory cytokine expressions of inducible nitric oxide synthase (iNOS), interleukin-1β (IL-1β), cyclooxygenase-2 (COX-2), and tumor necrosis factor-α (TNF-α). WBP mediated macrophages RAW 264.7 pro-inflammatory response through phosphatidylinositol 3 hydroxykinase/protein kinase B (PI3K/Akt) signaling pathway by significantly promoting Akt and phosphoinositide-dependent kinase 1 (PDK1) phosphorylations. Meanwhile, the expression of related phosphorylated proteins JNK and ERK1/2 was significantly up-regulated which suggested that WBP played pro-inflammatory roles by activating mitogen-activated protein kinases (MAPKs) signaling pathway. PRACTICAL APPLICATIONS: In recent years, wheat bran generally has the phenomenon of high yield and low utilization rate. Wheat bran has rich nutritional value and contains a lot of effective biologically active substances. Based on our findings, the water-soluble polysaccharides extracted from wheat bran have significant effects on regulating immunity and can be utilized as sources of natural immune modulators. The research can develop new functions of wheat bran polysaccharides, and improve processing utilization rate and product added value.
Keywords: MAPKs; PI3K/Akt; characterization; pro-inflammatory activities; wheat bran polysaccharides.
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