Sanchez Selien, Lemmens Stefanie, Baeten Paulien, Sommer Daniela, Dooley Dearbhaile, Hendrix Sven, Gou Fabregas Myriam
Department of Morphology, Biomedical Research Institute, Hasselt University, Diepenbeek BE3590, Belgium.
Health Science Centre, School of Medicine, University College Dublin, Dublin D04 V1W8, Ireland.
Exp Neurobiol. 2018 Oct;27(5):437-452. doi: 10.5607/en.2018.27.5.437. Epub 2018 Oct 31.
After spinal cord injury (SCI), monocyte derived macrophages play a detrimental role. Histone deacetylases (HDACs) are central epigenetic regulators of macrophage-polarization. We hypothesized that HDAC3 inhibition suppresses the pro-inflammatory macrophage phenotype (M1), promotes the anti-inflammatory phenotype (M2) and improves functional recovery after SCI. Therefore, two inhibitors of HDAC3 were selected, namely scriptaid and RGFP966. The impact on macrophage polarization was studied by investigating the effect on gene and protein expression of selected M1 and M2 markers. We show that scriptaid differentially influences M1 and M2 markers. It increases CD86 and iNOS gene expression and decreases GPR18, CD38, FPR2 and Arg-1 gene expression as well as the production of IL-6 and NO. RGFP966 primarily increased the expression of the M2 markers Arg-1 and Ym1 and reduced the production of IL-6 (M1). RGFP966 and scriptaid reduced the formation of foamy macrophages. Finally, to investigate the impact of HDAC3 inhibition on functional recovery after SCI, we studied the effects of RGFP966 and scriptaid in an T-cut hemisection SCI model. Histological analyses were performed on spinal cord sections to determine lesion size and astrogliosis, demyelinated area and selected infiltrating immune cells. RGFP966 and scriptaid did not affect functional recovery or histopathological outcome after SCI. In conclusion, these results indicate that specific HDAC3 inhibition with RGFP966 promotes alternative activation of macrophages and reduces the formation of foamy macrophages, but does not lead to a better functional recovery after SCI.
脊髓损伤（SCI）后，单核细胞衍生的巨噬细胞发挥有害作用。组蛋白脱乙酰酶（HDACs）是巨噬细胞极化的核心表观遗传调节因子。我们假设抑制HDAC3可抑制促炎巨噬细胞表型（M1），促进抗炎表型（M2），并改善脊髓损伤后的功能恢复。因此，选择了两种HDAC3抑制剂，即司立通和RGFP966。通过研究对选定的M1和M2标志物的基因和蛋白表达的影响，来探讨其对巨噬细胞极化的影响。我们发现司立通对M1和M2标志物有不同的影响。它增加CD86和诱导型一氧化氮合酶（iNOS）的基因表达，降低GPR18、CD38、甲酰肽受体2（FPR2）和精氨酸酶1（Arg-1）的基因表达以及白细胞介素-6（IL-6）和一氧化氮（NO）的产生。RGFP966主要增加M2标志物Arg-1和Ym1的表达，并减少IL-6（M1）的产生。RGFP966和司立通减少了泡沫巨噬细胞的形成。最后，为了研究抑制HDAC3对脊髓损伤后功能恢复的影响，我们在T形半切脊髓损伤模型中研究了RGFP966和司立通的作用。对脊髓切片进行组织学分析，以确定损伤大小、星形胶质细胞增生、脱髓鞘区域和选定的浸润免疫细胞。RGFP966和司立通对脊髓损伤后的功能恢复或组织病理学结果没有影响。总之，这些结果表明，用RGFP966特异性抑制HDAC3可促进巨噬细胞的替代性激活并减少泡沫巨噬细胞的形成，但不会导致脊髓损伤后更好的功能恢复。
