Department of Food Science, University of Wisconsin-Madison, Babcock Hall, 1605 Linden Drive, Madison, WI 53706, USA.
Department of Food Science, University of Wisconsin-Madison, Babcock Hall, 1605 Linden Drive, Madison, WI 53706, USA.
Free Radic Biol Med. 2018 Dec;129:548-558. doi: 10.1016/j.freeradbiomed.2018.10.424. Epub 2018 Oct 17.
The Allium vegetable-derived metabolite, S-alk(en)ylmercaptocysteine (CySSR), has been reported to modulate oxidative stress and inflammatory responses. However, the underlying mechanisms of action and structure-activity relationships are not completely understood. We investigated the mechanistic basis of the protective effects of CySSR on pro-inflammatory responses involving redox/oxidative stress induced by E. coli lipopolysaccharide (LPS) using RAW 264.7 cells. CySSR (R = allyl, "A" or 1-propenyl, "Pe") pre-treatments conferred concentration-dependent reductions in cytokines (TNF-α, IL-1β and IL-6), NO production and iNOS (inducible nitric synthase) overexpression, and attenuated oxidant production in LPS-stimulated RAW 264.7 cells where viability remained > 90%. These protective effects were manifested through inhibited activation of the nuclear factor-kappa B (NF-κB) signaling pathway via suppression of the IκB kinases (IKK) phosphorylation possibly by transforming growth factor β-activated kinase 1 or a kinase further upstream the canonical NF-κB signaling pathway. The attenuation of LPS-induced inflammation by CySSRs was associated with enhanced levels of cellular cysteine (CySH) and glutathione (GSH) mediated by cellular import/reduction of CySSR and the induction of glutamate cysteine ligase (GCL), one of > 200 nuclear factor erythroid 2-related factor 2 (Nrf2) regulated proteins. The reduction of anti-inflammatory effect of CySSR following pretreatment of cells with L-buthionine-S,R-sulfoximine (BSO) implicates GSH having a major role in reducing inflammation, likely in the context of other Nrf2-regulated antioxidant enzymes that scavenge HO and peroxides using GSH as co-substrate. The anti-inflammatory effect of CySSPe was significantly greater than CySSA for almost all indicators measured, and cell metabolites of CySSRs may have a role in attenuating NF-κB signaling.
植物大蒜衍生的代谢物 S-烯丙基巯基半胱氨酸（CySSR）已被报道可调节氧化应激和炎症反应。然而，其作用机制和构效关系尚不完全清楚。我们使用 RAW 264.7 细胞研究了 CySSR 对大肠杆菌脂多糖（LPS）诱导的氧化还原/氧化应激引起的促炎反应的保护作用的机制基础。CySSR（R = 丙烯基，“A”或 1-丙烯基，“Pe”）预处理可浓度依赖性地降低细胞因子（TNF-α、IL-1β和 IL-6）、NO 产生和诱导型一氧化氮合酶（iNOS）过表达，并减轻 LPS 刺激的 RAW 264.7 细胞中的氧化剂产生，而细胞活力仍保持在>90%。这些保护作用是通过抑制核因子-κB（NF-κB）信号通路的激活来实现的，其机制可能是通过转化生长因子β激活激酶 1 或 NF-κB 信号通路上游的激酶来抑制 IκB 激酶（IKK）磷酸化。CySSRs 通过增强细胞半胱氨酸（CySH）和谷胱甘肽（GSH）水平来减轻 LPS 诱导的炎症，这是通过细胞内导入/还原 CySSR 以及诱导谷氨酸半胱氨酸连接酶（GCL）实现的，GCL 是核因子红细胞 2 相关因子 2（Nrf2）调节的 200 多种蛋白质之一。在用 L-丁硫氨酸-S，R-亚砜（BSO）预处理细胞后，CySSR 的抗炎作用降低，表明 GSH 在减轻炎症中起主要作用，可能在其他 Nrf2 调节的抗氧化酶的背景下，这些酶使用 GSH 作为共底物来清除 HO 和过氧化物。CySSPe 的抗炎作用几乎在所有测量指标上均显著大于 CySSA，CySSR 的细胞代谢产物可能在减弱 NF-κB 信号中发挥作用。
