Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute (LDRI), Université catholique de Louvain (UCL), Av. E. Mounier, 72 (B1.72.01), 1200, Bruxelles, Belgium.
J Neuroinflammation. 2018 Mar 9;15(1):74. doi: 10.1186/s12974-018-1114-8.
Oxysterols are cholesterol derivatives that have been suggested to play a role in inflammatory diseases such as obesity, atherosclerosis, or neuroinflammatory diseases. However, the effect of neuroinflammation on oxysterol levels has only been partially studied so far.
We used an HPLC-MS method to quantify over ten oxysterols both in in vitro and in vivo models of neuroinflammation. In the same models, we used RT-qPCR to analyze the expression of the enzymes responsible for oxysterol metabolism. Using the BV2 microglial cell line, we explored the effect of lipopolysaccharide (LPS)-induced (M1-type) and IL-4-induced (M2-type) cell activation on oxysterol levels. We also used LPS-activated co-cultures of mouse primary microglia and astrocytes. In vivo, we induced a neuroinflammation by administering LPS to mice. Finally, we used a mouse model of multiple sclerosis, namely the experimental autoimmune encephalomyelitis (EAE) model, that is characterized by demyelination and neuroinflammation.
In vitro, we found that LPS activation induces profound alterations in oxysterol levels. Interestingly, we could discriminate between control and LPS-activated cells based on the changes in oxysterol levels both in BV2 cells and in the primary co-culture of glial cells. In vivo, the changes in oxysterol levels were less marked than in vitro. However, we found in both models increased levels of the GPR183 agonist 7α,25-dihydroxycholesterol. Furthermore, we studied in vitro the effect of 14 oxysterols on the mRNA expression of inflammatory markers in LPS-activated co-culture of microglia and astrocytes. We found that several oxysterols decreased the LPS-induced expression of pro-inflammatory markers.
These data demonstrate that inflammation profoundly affects oxysterol levels and that oxysterols can modulate glial cell activation. This further supports the interest of a large screening of oxysterol levels when studying the interplay between neuroinflammation and bioactive lipids.
氧化固醇是胆固醇的衍生物，据推测它们在肥胖、动脉粥样硬化或神经炎症性疾病等炎症性疾病中发挥作用。然而，神经炎症对氧化固醇水平的影响迄今仅部分研究过。
我们使用 HPLC-MS 方法来定量测定体外和体内神经炎症模型中的十多种氧化固醇。在相同的模型中，我们使用 RT-qPCR 来分析负责氧化固醇代谢的酶的表达。使用 BV2 小胶质细胞系，我们研究了脂多糖（LPS）诱导的（M1 型）和 IL-4 诱导的（M2 型）细胞激活对氧化固醇水平的影响。我们还使用 LPS 激活的小鼠原代小胶质细胞和星形胶质细胞共培养物。在体内，我们通过给小鼠注射 LPS 来诱导神经炎症。最后，我们使用多发性硬化症的小鼠模型，即实验性自身免疫性脑脊髓炎（EAE）模型，该模型的特点是脱髓鞘和神经炎症。
在体外，我们发现 LPS 激活诱导氧化固醇水平发生深刻变化。有趣的是，我们可以根据 BV2 细胞和原代神经胶质细胞共培养物中氧化固醇水平的变化来区分对照和 LPS 激活的细胞。在体内，氧化固醇水平的变化不如体外明显。然而，我们在这两种模型中都发现了 GPR183 激动剂 7α,25-二羟胆固醇水平升高。此外，我们在体外研究了 14 种氧化固醇对 LPS 激活的小胶质细胞和星形胶质细胞共培养物中炎症标志物 mRNA 表达的影响。我们发现，几种氧化固醇降低了 LPS 诱导的促炎标志物的表达。
这些数据表明炎症会深刻影响氧化固醇水平，而氧化固醇可以调节神经胶质细胞的激活。这进一步支持了在研究神经炎症与生物活性脂质相互作用时对氧化固醇水平进行大规模筛选的兴趣。
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