title: 17β-estradiol attenuates homocysteine-induced oxidative stress and inflammatory response as well as MAPKs cascade via activating PI3-K/Akt signal transduction pathway in Raw 264.7 cells.
abstract: Oxidative stress, inflammatory response, and mitogen-activated protein kinases (MAPKs) cascade are significant pathogenic factors of osteoporosis. It has been reported that elevated homocysteine (Hcy) may activate oxidative stress and reduce bone mineral density in post-menopausal osteoporosis. Moreover, hormone replacement therapy has been widely used in clinic to prevent and treat post-menopausal women with osteoporosis and osteoporotic fracture, but the molecular mechanisms and relevant signal transduction pathways underlying the action of Hcy remain unclear. In this study, we investigated the effects of 17β-estradiol (17β-E2) on the Hcy-induced oxidative stress, inflammatory response and MAPKs cascade, as well as the underlying signal transduction pathway in murine Raw 264.7 cells. The reactive oxygen species (ROS) was assessed by fluorospectrophotometry. The proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β were analyzed by double-immunofluorescence labeling and reverse transcriptase polymerase chain reaction assay, respectively. Furthermore, phosphorylation levels of MAPKs cascade were measured by western blot analysis. A specific phosphatidylinositol 3-kinase (PI3-K) inhibitor, Wortmannin (1 μM) was employed to determine whether PI3-K/Akt signaling pathway mediated the 17β-E2's effect on Raw 264.7 cells. 17β-E2 markedly decreased the ROS production induced by Hcy, the expression of TNF-α and IL-1β at protein and mRNA levels, and down-regulated the phosphorylation of MAPKs (ERK1/2, JNK and p38). These suppressing effects of 17β-E2 on Hcy-induced changes were reversed by pretreatment with PI3-K inhibitor Wortmannin. The results indicate that 17β-estradiol may attenuate Hcy-induced oxidative stress, inflammatory response and up-regulation of MAPKs in Raw 264.7 cells via PI3-K/Akt signal transduction pathway.
authors.affiliation: Department of Pathophysiology, Basic Medical School, Kunming Medical University, Kunming 650500, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Anatomy, Basic Medical School, Kunming Medical University, Kunming 650500, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Anatomy, Basic Medical School, Kunming Medical University, Kunming 650500, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zong
authors.affiliation: Department of Anatomy, Basic Medical School, Kunming Medical University, Kunming 650500, China.
authors.forename: Jiazhi
authors.initials: J
authors.lastname: Guo
authors.affiliation: Department of Cardiology, The Second Affiliated Hospital, Kunming Medical University, Kunming 650101, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Endocrinology, The Third People's Hospital of Yunnan Province, Kunming 650011, China.
authors.forename: Yunbing
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Orthopedics, The Third Affiliated Hospital, Yunnan Traditional Chinese Medicine College, Kunming 650031, China guili0527@126.com dongwei310@126.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Dong
authors.affiliation: Department of Endocrinology, The Third People's Hospital of Yunnan Province, Kunming 650011, China guili0527@126.com dongwei310@126.com.
authors.forename: Li
authors.initials: L
authors.lastname: Gui
mesh_terms: D000818:Animals; D002470:Cell Survival; D004958:Estradiol / Q000378:metabolism*; D006710:Homocysteine / Q000378:metabolism; D007249:Inflammation / Q000378:metabolism*; D053583:Interleukin-1beta / Q000378:metabolism; D020935:MAP Kinase Signaling System; D051379:Mice; D010024:Osteoporosis / Q000378:metabolism; D018384:Oxidative Stress; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000067996:RAW 264.7 Cells; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D053583:Interleukin-1beta; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D006710:Homocysteine; D004958:Estradiol; D019869:Phosphatidylinositol 3-Kinases
keywords: 17β-estradiol; MAPKs; PI3-K/Akt; homocysteine; reactive oxygen species