Phloretin Suppresses Bone Morphogenetic Protein-2-Induced Osteoblastogenesis and Mineralization via Inhibition of Phosphatidylinositol 3-kinases/Akt Pathway
Phloretin Suppresses Bone Morphogenetic Protein-2-Induced Osteoblastogenesis and Mineralization via Inhibition of Phosphatidylinositol 3-kinases/Akt Pathway
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DOI：
10.3390/ijms20102481
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发表时间：
2019-05-02
影响因子：
5.6
通讯作者：
Sugimoto, Toshitsugu
中科院分区：
文献类型：
--
作者：
Takeno, Ayumu;Kanazawa, Ippei;Sugimoto, Toshitsugu
根癌素有多效性，包括抑制葡萄糖转运蛋白(GLUT)。我们先前的研究表明，根癌素能促进骨髓基质细胞(BMSC)ST2的脂肪生成，而不依赖于GLUT1的抑制作用。本研究探讨了根癌蛋白对ST2细胞和成骨细胞MC3T3-E1成骨细胞分化的影响。10-100 mU M根癌素能抑制成骨细胞分化标记物的矿化和表达，如碱性磷酸酶(ALP)、骨钙素(OCN)、1型胶原、矮小相关转录因子2(Runx2)和骨钙素(OSX)，而成脂标记物(PPAR)、CCAAT/增强子结合蛋白(C/EBP)、脂肪酸结合蛋白4和脂联素增加。根癌素能抑制MC3T3-E1细胞矿化，降低成骨细胞分化标志物。根癌素能抑制ST2细胞Akt的磷酸化。此外，磷脂酰肌醇3-激酶(PI3K)/Akt抑制剂LY294002可抑制成骨细胞的矿化和除碱性磷酸酶外的成骨分化标志物的表达。SiRNA沉默Glut1对矿化无影响，但降低了OCN的表达，增加了ALP、Runx2和OSX的表达。GLUT1沉默对成骨细胞分化标志物和矿化的影响与根癌蛋白不一致。综上所述，这些发现提示根癌素能通过抑制PI3K/Akt通路抑制ST2和MC3T3-E1细胞的成骨细胞的生成，提示根癌菌素的作用可能与抑制葡萄糖摄取无关。
Phloretin has pleiotropic effects, including glucose transporter (GLUT) inhibition. We previously showed that phloretin promoted adipogenesis of bone marrow stromal cell (BMSC) line ST2 independently of GLUT1 inhibition. This study investigated the effect of phloretin on osteoblastogenesis of ST2 cells and osteoblastic MC3T3-E1 cells. Treatment with 10 to 100 mu M phloretin suppressed mineralization and expression of osteoblast differentiation markers, such as alkaline phosphatase (ALP), osteocalcin (OCN), type 1 collagen, runt-related transcription factor 2 (Runx2), and osterix (Osx), while increased adipogenic markers, peroxisome proliferator-activated receptor (PPAR), CCAAT/enhancer-binding protein (C/EBP), fatty acid-binding protein 4, and adiponectin. Phloretin also inhibited mineralization and decreased osteoblast differentiation markers of MC3T3-E1 cells. Phloretin suppressed phosphorylation of Akt in ST2 cells. In addition, treatment with a phosphatidylinositol 3-kinase (PI3K)/Akt inhibitor, LY294002, suppressed the mineralization and the expression of osteoblast differentiation markers other than ALP. GLUT1 silencing by siRNA did not affect mineralization, although it decreased the expression of OCN and increased the expression of ALP, Runx2, and Osx. The effects of GLUT1 silencing on osteoblast differentiation markers and mineralization were inconsistent with those of phloretin. Taken together, these findings suggest that phloretin suppressed osteoblastogenesis of ST2 and MC3T3-E1 cells by inhibiting the PI3K/Akt pathway, suggesting that the effects of phloretin may not be associated with glucose uptake inhibition.