The inhibitory effects of MIF on accumulation of canine degenerative myelopathy-associated mutant SOD1 aggregation
The inhibitory effects of MIF on accumulation of canine degenerative myelopathy-associated mutant SOD1 aggregation
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DOI：
10.1016/j.rvsc.2022.03.013
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发表时间：
2022-03-29
影响因子：
2.4
通讯作者：
Nishii, Naohito
中科院分区：
文献类型：
--
作者：
Nomura, Saki;Kobatake, Yui;Nishii, Naohito
犬退行性脊髓病（degenerative myelopathy，DM）是一种进行性神经退行性疾病，常与超氧化物歧化酶1（SOD 1）基因c.118G > A（p.E40K）错义突变有关。突变型SOD 1蛋白（SOD 1（E40 K））容易发生错误折叠、获得不溶性、聚集在神经细胞的胞浆中，导致神经组织变性。沿着分子伴侣活性，巨噬细胞迁移抑制因子（MIF）是一种多功能蛋白，已显示其直接抑制人突变型SOD 1错误折叠并增强表达突变型SOD 1的运动神经元的存活。本研究的目的是确定MIF是否也抑制DM相关的SOD1（E40K）错误折叠和SOD1聚集体的积累。人胚肾293A细胞转染SOD1（cWT）或SOD1（E40K）与或不与MIF。通过免疫细胞化学测量含有转染的SOD1聚集体的细胞的百分比，并且通过免疫印迹评估不溶性级分中的SOD1（E40K）的量。在MIF存在下，具有SOD 1（E40K）聚集体的细胞百分比和不溶性SOD 1（E40K）蛋白的量减少。由于MIF的伴侣活性有助于SOD 1（E40K）的折叠，并增强错误折叠的SOD 1（E40K）的重折叠和降解，因此本研究的结果表明，MIF通过其伴侣活性调节SOD 1聚集体的积累。我们建议，提高细胞内的MIF分子伴侣活性可能是一种有效的治疗糖尿病的策略。
Canine degenerative myelopathy (DM) is a progressive neurodegenerative disorder, which is commonly associated with c.118G > A (p. E40K) missense mutation in the superoxide dismutase 1 (SOD1) gene. Mutant SOD1 protein (SOD1(E40K)) is likely to be misfolded, acquire insolubility, aggregate in the cytoplasm of neural cells, and lead to degeneration of the nervous tissues. Along with a chaperone activity, macrophage migration inhibitory factor (MIF) is a multifunctional protein that has been shown to directly inhibit human mutant SOD1 misfolding and enhance survival of mutant SOD1-expressing motor neurons. The purpose of this study was to determine whether MIF also inhibits DM-related SOD1(E40K) misfolding and accumulation of SOD1 aggregates. Human embryonic kidney 293A cells were transfected SOD1(cWT) or SOD1(E40K) with or without MIF. The percentages of cells containing transfected SOD1 aggregates were measured by immunocytochemistry, and the amount of SOD1(E40K) in the insoluble fraction was evaluated by immunoblotting. The percentage of cells with SOD1(E40K) aggregates and the amount of insoluble SOD1(E40K) protein decreased in the presence of MIF. Because the chaperone activity of MIF assists in SOD1(E40K) folding and enhances the refolding and degradation of misfolded SOD1(E40K), the results of this study suggests that MIF regulates the accumulation of SOD1 aggregates by its chaperone activity. We propose that enhancing intracellular MIF chaperone activity could be an effective therapeutic strategy for DM.