Kim Sora, Ka Sun-O, Lee Youngyi, Park Byung-Hyun, Fei Xiang, Jung Jae-Kyung, Seo Seung-Yong, Bae Eun Ju
College of Pharmacy, Woosuk University, Wanju-gun, Jeollabuk-do, Korea.
Department of Biochemistry, Medical School and Diabetes Research Center, Chonbuk National University, Jeonju, Jeollabuk-do, Korea.
PLoS One. 2015 Feb 23;10(2):e0117120. doi: 10.1371/journal.pone.0117120. eCollection 2015.
Preventing pathologic tissue inflammation is key to treating obesity-induced insulin resistance and type 2 diabetes. Previously, we synthesized a series of methylhonokiol analogs and reported that compounds with a carbamate structure had inhibitory function against cyclooxygenase-2 in a cell-free enzyme assay. However, whether these compounds could inhibit the expression of inflammatory genes in macrophages has not been investigated. Here, we found that a new 4-O-methylhonokiol analog, 3',5-diallyl-4'-methoxy-[1,1'-biphenyl]-2-yl morpholine-4-carboxylate (GS12021) inhibited LPS- or TNFα-stimulated inflammation in macrophages and adipocytes, respectively. LPS-induced phosphorylation of nuclear factor-kappa B (NF-κB)/p65 was significantly decreased, whereas NF-κB luciferase activities were slightly inhibited, by GS12021 treatment in RAW 264.7 cells. Either mitogen-activated protein kinase phosphorylation or AP-1 luciferase activity was not altered by GS12021. GS12021 increased the phosphorylation of AMP-activated protein kinase (AMPK) α and the expression of sirtuin (SIRT) 1. Inhibition of mRNA expression of inflammatory genes by GS12021 was abolished in AMPKα1-knockdown cells, but not in SIRT1 knockout cells, demonstrating that GS12021 exerts anti-inflammatory effects through AMPKα activation. The transwell migration assay results showed that GS12021 treatment of macrophages prevented the cell migration promoted by incubation with conditioned medium obtained from adipocytes. GS12021 suppression of p65 phosphorylation and macrophage chemotaxis were preserved in AMPKα1-knockdown cells, indicating AMPK is not required for these functions of GS12021. Identification of this novel methylhonokiol analog could enable studies of the structure-activity relationship of this class of compounds and further evaluation of its in vivo potential for the treatment of insulin-resistant states and other chronic inflammatory diseases.
预防病理性组织炎症是治疗肥胖诱导的胰岛素抵抗和2型糖尿病的关键。此前，我们合成了一系列甲基厚朴酚类似物，并报道在无细胞酶测定中，具有氨基甲酸酯结构的化合物对环氧合酶-2具有抑制功能。然而，这些化合物是否能抑制巨噬细胞中炎症基因的表达尚未得到研究。在此，我们发现一种新的4-O-甲基厚朴酚类似物，3',5-二烯丙基-4'-甲氧基-[1,1'-联苯]-2-基吗啉-4-羧酸酯（GS12021）分别抑制巨噬细胞和脂肪细胞中LPS或TNFα刺激的炎症。在RAW 264.7细胞中，GS12021处理可使LPS诱导的核因子-κB（NF-κB）/p65磷酸化显著降低，而NF-κB荧光素酶活性略有抑制。GS12021对丝裂原活化蛋白激酶磷酸化或AP-1荧光素酶活性均无影响。GS12021增加了AMP活化蛋白激酶（AMPK）α的磷酸化和沉默调节蛋白（SIRT）1的表达。GS12021对炎症基因mRNA表达的抑制在AMPKα1基因敲低的细胞中被消除，但在SIRT1基因敲除的细胞中未被消除，表明GS12021通过激活AMPKα发挥抗炎作用。Transwell迁移试验结果表明，GS12021处理巨噬细胞可阻止与脂肪细胞条件培养基孵育所促进的细胞迁移。GS12021对p65磷酸化和巨噬细胞趋化性的抑制在AMPKα1基因敲低的细胞中得以保留，表明AMPK对GS12021的这些功能并非必需。鉴定这种新型甲基厚朴酚类似物有助于研究这类化合物的构效关系，并进一步评估其在体内治疗胰岛素抵抗状态和其他慢性炎症性疾病的潜力。
