Turku PET Centre, University of Turku, Turku, Finland.
Turku PET Centre, Åbo Akademi University, Turku, Finland.
J Neuroinflammation. 2021 Jan 20;18(1):30. doi: 10.1186/s12974-021-02073-7.
Activated macrophages in the experimental model of multiple sclerosis (MS) express folate receptor-β (FR-β), representing a promising target for the treatment of MS. Here, we both evaluated the efficacy of a novel folate-aminopterin construct (EC2319) in a rat focal model of multiple sclerosis (MS) and investigated the utility of Ga-labeled 1,4,7-triazacyclononane-1,4,7-triacetic acid-conjugated folate (Ga-FOL) for assessing inflammatory lesions. In addition, we investigated whether FR-β is expressed in the brain of patients with MS.
Focal delayed-type hypersensitivity experimental autoimmune encephalomyelitis (fDTH-EAE) was induced in 40 Lewis rats; 20 healthy Lewis rats were used as controls. Rats were divided into six groups according to the duration of disease (control, acute, or chronic) and intervention (vehicle versus EC2319). Ga-FOL analyses, histology, and immunofluorescence of the brain were performed to evaluate the efficacy of subcutaneously administered EC2319 on lesion development. Immunofluorescence was used to assess FR-β expression in postmortem brain samples from 5 patients with MS and 5 healthy controls.
Immunofluorescence and histological analyses revealed significant reductions in FR-β expression (P < 0.05) and lesion size (P < 0.01), as well as improved inducible nitric oxide synthase/mannose receptor C type 1 ratios (P < 0.01) in macrophages and microglia during the chronic but not acute phase of fDTH-EAE in EC2319-treated rats. The uptake of IV-injected Ga-FOL in the brain was low and did not differ between the groups, but the in vitro binding of Ga-FOL was significantly lower in EC2319-treated rats (P < 0.01). FR-β positivity was observed in chronically active lesions and in normal-appearing white matter in MS brain samples.
EC2319 was well tolerated and attenuated inflammation and lesion development in a rat model of a chronic progressive form of MS. Human MS patients have FR-β-positive cells in chronically active plaques, which suggests that these results may have translational relevance.
实验性多发性硬化症（MS）模型中的活化巨噬细胞表达叶酸受体-β（FR-β），这是治疗 MS 的一个有前途的靶点。在这里，我们评估了新型叶酸-氨蝶呤构建物（EC2319）在大鼠局灶性多发性硬化症（MS）模型中的疗效，并研究了 Ga 标记的 1,4,7-三氮杂环壬烷-1,4,7-三乙酸偶联叶酸（Ga-FOL）用于评估炎症病变的效用。此外，我们还研究了 FR-β是否在 MS 患者的大脑中表达。
在 40 只 Lewis 大鼠中诱导局灶性迟发型超敏实验性自身免疫性脑脊髓炎（fDTH-EAE）；20 只健康 Lewis 大鼠作为对照。根据疾病持续时间（对照、急性或慢性）和干预（载体与 EC2319），将大鼠分为六组。进行 Ga-FOL 分析、大脑组织学和免疫荧光，以评估皮下给予 EC2319 对病变发展的疗效。免疫荧光用于评估 5 例 MS 患者和 5 例健康对照者死后大脑样本中 FR-β 的表达。
免疫荧光和组织学分析显示，在 EC2319 治疗大鼠的 fDTH-EAE 慢性期而非急性期，FR-β表达（P<0.05）和病变大小（P<0.01）显著降低，诱导型一氧化氮合酶/甘露糖受体 C 型 1 比值（P<0.01）升高巨噬细胞和小胶质细胞中。脑内 IV 注射的 Ga-FOL 摄取量较低，各组之间无差异，但 EC2319 治疗大鼠的 Ga-FOL 体外结合显著降低（P<0.01）。FR-β 阳性见于慢性活动性病变和 MS 脑样本中的正常外观白质。
EC2319 耐受良好，可减轻大鼠慢性进行性 MS 模型中的炎症和病变发展。人类 MS 患者的慢性活动性斑块中有 FR-β 阳性细胞，这表明这些结果可能具有转化意义。
