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Int J Biol Macromol. 2015 Aug;79:971-82. doi: 10.1016/j.ijbiomac.2015.06.023. Epub 2015 Jun 17.

Immunostimulatory polysaccharide isolated from the leaves of Diospyros kaki Thumb modulate macrophage via TLR2.

Author information

1
Department of Pharmaceutical Biochemistry, College of Pharmacy, Kyung Hee University, Seoul 130-710, Republic of Korea; Department of Life and Nanopharmaceutical Science, Kyung Hee University, Seoul 130-710, Republic of Korea.
2
Department of Pharmaceutical Biochemistry, College of Pharmacy, Kyung Hee University, Seoul 130-710, Republic of Korea; Reactive Oxygen Species Medical Research Center, School of Medicine, Kyung Hee University, Seoul 130-710, Republic of Korea.
3
Department of Food Science and Biotechnology, Kyonggi University, Suwon, Gyeonggi-do 443-760, Republic of Korea.
4
Korea Food Research Institute, Seongnam, Gyeonggi-do 463-836, Republic of Korea.
5
Department of Pharmaceutical Biochemistry, College of Pharmacy, Kyung Hee University, Seoul 130-710, Republic of Korea; Department of Life and Nanopharmaceutical Science, Kyung Hee University, Seoul 130-710, Republic of Korea. Electronic address: ktlee@khu.ac.kr.

Abstract

The objective of this study was to investigate the immunostimulatory effects of a polysaccharide fraction from the leaves of Diospyros kaki Thumb (PLE0) and the molecular mechanism responsible for its action in RAW 264.7 macrophages as well as in vivo effects on cyclophosphamide-induced immunosuppression in mice. PLE0 concentration-dependently activated the expressions of inducible nitric oxide synthase (iNOS) at the protein and mRNA levels and its promoter activity, and that these activations caused attendant increases the nitric oxide (NO) production. In addition, PLE0 increased the mRNA expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6. Molecular data revealed that PLE0 increased the transcriptional activity and nuclear translocation of nuclear factor-κB (NF-κB) by inducing the degradation of inhibitory κBα (IκBα) and the phosphorylation of inhibitory κB kinase (IKK). Moreover, anti-toll-like receptor 2 (TLR2) antibody and myeloid differentiation primary response gene 88 (MyD88)-specific siRNA significantly reduce PLE0-induced NO production in RAW 264.7 macrophages. Pretreatment with PLE0 recovered cyclophosphamide-induced reductions in thymus and spleen indices as well as neutrophil counts. Taken together, our data suggest that PLE0 up-regulates the expressions of iNOS, TNF-α, IL-1β, and IL-6 genes by activating TLR2-mediated NF-κB activations, and that these actions are responsible for its immunostimulatory effects.

KEYWORDS:

Immunostimulatory effects; Polysaccharide; Toll-like receptor 2

PMID:
26093315
DOI:
10.1016/j.ijbiomac.2015.06.023
[Indexed for MEDLINE]

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