The online version of this article (doi:10.1186/s12974-017-0839-0) contains supplementary material, which is available to authorized users.
Ganoderma lucidum (GL) has been widely used in Asian countries for hundreds of years to promote health and longevity. The pharmacological functions of which had been classified, including the activation of innate immune responses, suppression of tumour and modulation of cell proliferations. Effective fractions of Ganoderma lucidum polysaccharides (GLP) had already been reported to regulate the immune system. Nevertheless, the role of GLP in the microglia-mediated neuroinflammation has not been sufficiently elucidated. Further, GLP effect on microglial behavioural modulations in correlation with the inflammatory responses remains to be unravelled. The aim of this work was to quantitatively analyse the contributions of GLP on microglia.
The BV2 microglia and primary mouse microglia were stimulated by lipopolysaccharides (LPS) and amyloid beta42 (Aβ42) oligomer, respectively. Investigation on the effect of GLP was carried by quantitative determination of the microglial pro- and anti-inflammatory cytokine expressions and behavioural modulations including migration, morphology and phagocytosis. Analysis of microglial morphology and phagocytosis modulations was confirmed in the zebrafish brain.
Quantitative results revealed that GLP down-regulates LPS- or Aβ-induced pro-inflammatory cytokines and promotes anti-inflammatory cytokine expressions in BV-2 and primary microglia. In addition, GLP attenuates inflammation-related microglial migration, morphological alterations and phagocytosis probabilities. We also showed that modulations of microglial behavioural responses were associated with MCP-1 and C1q expressions.
Overall, our study provides an insight into the GLP regulation of LPS- and Aβ-induced neuroinflammation and serves an implication that the neuroprotective function of GLP might be achieved through modulation of microglial inflammatory and behavioural responses.
Additional file 1: Figure S1. GLP exhibited no cytotoxicity and proliferative effect to BV2 cells. (A) GLP effect on BV2 cell viability was examined for 24 h in the presence and absence of LPS stimulation. No cytotoxicity was detected. GLP long-term effect on cell growth was investigated for 48, 72 and 96 h. Cell growth was estimated by total cell count (B) and CellTiter-Glo assay (C). Cells were incubated in normal DMEM culture medium with 10% FBS supplement. Both 1 and 0.01 μg/ml showed no effect on cell growth compared to untreated control. Cells grown in FBS-depleted medium (2% FBS) showed little cell growth, whereas in the FBS-enriched medium (30% FBS), the cell growth exceeds normal cultured medium. Figure S2. Confirmation on the integrity of prepared Aβ oligomer. Four microliters of oligomers or fibril were loaded to the nitrocellulose membrane. Dot blot was performed and the oligomer-(A11) and Fibril-specific (ab126468) antibodies were used. In the prepared oligomer (left lane), little fibril fractions were detected, whilst in the prepared Aβ fibril (right lane), certain levels of oligomers were also detected. Staining of 6E10 revealed the total Aβ content. (PDF 207 kb)12974_2017_839_MOESM1_ESM.pdf
Macauley MS, Crocker PR, Paulson JC. Siglec-mediated regulation of immune cell function in disease. Nat Rev Immunol. 2014;14:653–66. Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved. Available from: http://dx.doi.org/10.1038/nri3737. CrossRefPubMedPubMedCentral
Claude J, Linnartz-Gerlach B, Kudin AP, Kunz WS, Neumann H. Microglial CD33-related siglec-E inhibits neurotoxicity by preventing the phagocytosis-associated oxidative burst. J Neurosci. 2013;33:18270. LP – 18276. Available from: http://www.jneurosci.org/content/33/46/18270.abstract. CrossRefPubMedPubMedCentral
Neumann J, Sauerzweig S, Rönicke R, Gunzer F, Dinkel K, Ullrich O, et al. Microglia cells protect neurons by direct engulfment of invading neutrophil granulocytes: a new mechanism of CNS immune privilege. J Neurosci. 2008;28:5965. LP – 5975. Available from: http://www.jneurosci.org/content/28/23/5965.abstract. CrossRefPubMed
Saha RN, Pahan K. Regulation of inducible nitric oxide synthase gene in glial cells. Antioxid Redox Signal. 2006;8:929–47. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1963415/. CrossRefPubMedPubMedCentral
Huang S, Mao J, Ding K, Zhou Y, Zeng X, Yang W, et al. Polysaccharides from Ganoderma lucidum promote cognitive function and neural progenitor proliferation in mouse model of Alzheimer’s disease. Stem Cell Rep. 2017;8:84–94. United States. CrossRef
Tremblay M-È, Lowery RL, Majewska AK. Microglial interactions with synapses are modulated by visual experience. PLoS Biol. 2010;8. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2970556/.
Fontainhas AM, Wang M, Liang KJ, Chen S, Mettu P, Damani M, et al. Microglial morphology and dynamic behavior is regulated by ionotropic glutamatergic and GABAergic neurotransmission. Block M, editor. PLoS One. 2011;6:e15973. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3026789/. CrossRefPubMedPubMedCentral
Peri F, Nüsslein-Volhard C. Live imaging of neuronal degradation by microglia reveals a role for v0-ATPase a1 in phagosomal fusion in vivo. Cell. 2008;133:916–27. Available from: http://www.sciencedirect.com/science/article/pii/S0092867408006119. CrossRefPubMed
Park H-C, Kim C-H, Bae Y-K, Yeo S-Y, Kim S-H, Hong S-K, et al. Analysis of upstream elements in the HuC promoter leads to the establishment of transgenic zebrafish with fluorescent neurons. Dev Biol. 2000;227:279–93. Available from: http://www.sciencedirect.com/science/article/pii/S0012160600998981. CrossRefPubMed
Herbomel P, Thisse B, Thisse C. Ontogeny and behaviour of early macrophages in the zebrafish embryo. Development. 1999;126:3735–45. England. PubMed
- Polysaccharides from Ganoderma lucidum attenuate microglia-mediated neuroinflammation and modulate microglial phagocytosis and behavioural response
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