Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria.
Department of Neuroscience, Centre de Recherche du CHUM, Université de Montréal, Montréal, QC H2X 0A9, Canada.
Biomolecules. 2023 Nov 23;13(12):1696. doi: 10.3390/biom13121696.
Elevated levels of saturated very long-chain fatty acids (VLCFAs) in cell membranes and secreted lipoparticles have been associated with neurotoxicity and, therefore, require tight regulation. Excessive VLCFAs are imported into peroxisomes for degradation by β-oxidation. Impaired VLCFA catabolism due to primary or secondary peroxisomal alterations is featured in neurodegenerative and neuroinflammatory disorders such as X-linked adrenoleukodystrophy and multiple sclerosis (MS). Here, we identified that healthy human macrophages upregulate the peroxisomal genes involved in β-oxidation during myelin phagocytosis and pro-inflammatory activation, and that this response is impaired in peripheral macrophages and phagocytes in brain white matter lesions in MS patients. The pharmacological targeting of VLCFA metabolism and peroxisomes in innate immune cells could be favorable in the context of neuroinflammation and neurodegeneration. We previously identified the epigenetic histone deacetylase (HDAC) inhibitors entinostat and vorinostat to enhance VLCFA degradation and pro-regenerative macrophage polarization. However, adverse side effects currently limit their use in chronic neuroinflammation. Here, we focused on tefinostat, a monocyte/macrophage-selective HDAC inhibitor that has shown reduced toxicity in clinical trials. By using a gene expression analysis, peroxisomal β-oxidation assay, and live imaging of primary human macrophages, we assessed the efficacy of tefinostat in modulating VLCFA metabolism, phagocytosis, chemotaxis, and immune function. Our results revealed the significant stimulation of VLCFA degradation with the upregulation of genes involved in peroxisomal β-oxidation and interference with immune cell recruitment; however, tefinostat was less potent than the class I HDAC-selective inhibitor entinostat in promoting a regenerative macrophage phenotype. Further research is needed to fully explore the potential of class I HDAC inhibition and downstream targets in the context of neuroinflammation.
细胞膜中和分泌的脂蛋白中饱和的超长链脂肪酸 (VLCFA) 水平升高与神经毒性有关,因此需要严格调节。过量的 VLCFA 被导入过氧化物酶体进行β-氧化降解。由于原发性或继发性过氧化物酶体改变导致的 VLCFA 分解代谢受损,是神经退行性和神经炎症性疾病的特征,如 X 连锁肾上腺脑白质营养不良和多发性硬化症 (MS)。在这里,我们发现健康的人巨噬细胞在吞噬髓磷脂和促炎激活过程中上调参与β-氧化的过氧化物酶体基因,而在 MS 患者大脑白质病变的外周巨噬细胞和吞噬细胞中,这种反应受损。在先天免疫细胞中靶向 VLCFA 代谢和过氧化物酶体可能有利于神经炎症和神经退行性变。我们之前发现组蛋白去乙酰化酶 (HDAC) 抑制剂恩替诺特和伏立诺他可增强 VLCFA 降解和促再生巨噬细胞极化。然而,目前的不良反应限制了它们在慢性神经炎症中的应用。在这里,我们专注于替芬诺特,一种单核细胞/巨噬细胞选择性 HDAC 抑制剂,在临床试验中显示出降低的毒性。通过使用基因表达分析、过氧化物酶体 β-氧化测定和原代人巨噬细胞的活细胞成像,我们评估了替芬诺特调节 VLCFA 代谢、吞噬作用、趋化性和免疫功能的功效。我们的结果表明,VLCFA 降解显著增加,与过氧化物酶体 β-氧化相关的基因上调,并干扰免疫细胞募集;然而,替芬诺特在促进再生巨噬细胞表型方面不如 I 类 HDAC 选择性抑制剂恩替诺特有效。需要进一步研究以充分探索神经炎症背景下 I 类 HDAC 抑制及其下游靶点的潜力。