Anti-inflammatory effects of genistein via suppression of the toll-like receptor 4-mediated signaling pathway in lipopolysaccharide-stimulated BV2 microglia.
Genistein, a principal soy isoflavone, has received considerable attention as a protein kinase inhibitor. Although some studies have demonstrated that genistein possesses anti-inflammatory effects, the molecular mechanisms of genistein-mediated anti-inflammatory potential are unclear in microglial cells. In this study, we determined whether genistein attenuates pro-inflammatory responses in lipopolysaccharide (LPS)-stimulated BV2 microglia and attempted to establish the possible mechanisms. Our results indicated that genistein inhibited the production of nitric oxide (NO) and prostaglandin E2 at non-toxic concentrations by inhibiting inducible NO synthase and cyclooxygenase-2 expression. The increased release and expression of inflammatory cytokines, including interleukin-1β, tumor necrosis factor-α, by LPS, were markedly reduced by genistein. Genistein also attenuated LPS-induced reactive oxygen species generation and LPS-mediated nuclear translocation of nuclear factor-kappa B (NF-κB), associated with blocking degradation of the inhibitor of NF-κB-α. Furthermore, genistein potently suppressed binding of LPS to the microglial cell surface, indicating the antagonistic effect of genistein against toll like receptor 4 (TLR4), and inhibited LPS-induced TLR4 and myeloid differentiation factor 88 expression. In addition, blocking TLR4 signaling using the specific TLR4 signaling inhibitor CLI-095 increased the anti-inflammatory potential of genistein in BV2 microglia. Our data indicate that genistein may attenuate the initiation of intracellular signaling cascades by LPS through inhibiting NF-κB activation by inhibiting the binding of LPS to TLR-4 on microglial cells.
Center for Core Research Facilities, Daegu-Gyeongbuk Institute of Science & Technology, Daegu 711-873, Republic of Korea.
Jin-Woo
JW
Jeong
Department of Biotechnology, College of Natural Resources and Life Science, Dong-A University, Busan 604-714, Republic of Korea.
Hye Hyeon
HH
Lee
Department of Biochemistry, Dongeui University College of Oriental Medicine, Busan 614-714, Republic of Korea; Anti-Aging Research Center & Blue-Bio Industry RIC, Dongeui University, Busan 614-714, Republic of Korea.
Min Ho
MH
Han
Laboratory of Immunobiology, Department of Marine Life Sciences, Jeju National University, Jeju 690-756, Republic of Korea.
Gi-Young
GY
Kim
Department of Urology, Chungbuk National University College of Medicine, Cheongju 361-763, Republic of Korea.
Wun-Jae
WJ
Kim
Department of Biochemistry, Dongeui University College of Oriental Medicine, Busan 614-714, Republic of Korea; Anti-Aging Research Center & Blue-Bio Industry RIC, Dongeui University, Busan 614-714, Republic of Korea. Electronic address: choiyh@deu.ac.kr.
Yung Hyun
YH
Choi
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics; D015232:Dinoprostone / Q000096:biosynthesis; D015536:Down-Regulation / Q000187:drug effects; D019833:Genistein / Q000494:pharmacology*; D053583:Interleukin-1beta / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000494:pharmacology*; D017628:Microglia / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D051996:Transcription Factor RelA / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D000893:Anti-Inflammatory Agents; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D053594:Myeloid Differentiation Factor 88; D051197:Toll-Like Receptor 4; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D019833:Genistein; D052247:Nitric Oxide Synthase Type II; D051546:Cyclooxygenase 2; D015232:Dinoprostone
Anti-inflammation; BV2 microglia; Genistein; NF-κB; TLR4