Enhanced Dectin-2 gene expression by lignin-carbohydrate complex in macrophages

Objective: Lignin carbohydrate complex (LCC) fractions of Lentinus edodes mycelia extract (LEM) have shown anti-HIV and immunopotentiating activity. In contrast to polysaccharides, the signaling pathway for LCC has not been identified. Macrophages play an important role in the innate inflammatory response during the progression of periodontal disease. We performed DNA microarray analysis of the possible changes in the gene expression of various receptors after treatment with LCC in mouse macrophage-like J774.1 cells. Methods: RNA was isolated with Qiagen RNeasy Plus Mini kit, hydridized with GeneChip MouseGene 1.0 ST arrays, and scanned with Affymetrix GeneChip Command Console software. Results: One of the seven LCC fractions isolated from LEM (Fr4) affected immune response-related gene expression, but did not affect the expression of as many as genes as LPS did. Fr4 enhanced the expression of dectin-2 (4.2-fold) and TLR-2 (2.5-fold) prominently, but only slightly modified the expression of dectin-1 (0.8-fold), complement receptor 3 (0.9-fold), TLR1, 3, 4, 9 and 13 (0.8- to 1.7-fold), Sykb, Zap70, Jak2 (1.0- to 1.2-fold), Nfκb1, NFκb2, Rela, Relb (1.0- to 1.6-fold), Nfκbia, Nfκbib, Nfκbie, Nfκbi12 and Nfκbiz (0.8- to 2.3-fold). On the other hand,LPS did not affect the expression of dectin-2 nor TLR-2. Conclusion: These data suggest the significant role of the activation of the dectin-2 signaling pathway in the action of LCC on macrophages.