The SYNGAP1 3'UTR Variant in ALS Patients Causes Aberrant SYNGAP1 Splicing and Dendritic Spine Loss by Recruiting HNRNPK.
The SYNGAP1 3'UTR Variant in ALS Patients Causes Aberrant SYNGAP1 Splicing and Dendritic Spine Loss by Recruiting HNRNPK.
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DOI：
10.1523/jneurosci.0455-22.2022
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发表时间：
2022-11-23
影响因子：
5.3
通讯作者：
Sobue, Gen
中科院分区：
文献类型：
--
作者：
Yokoi, Satoshi;Ito, Takuji;Sahashi, Kentaro;Nakatochi, Masahiro;Nakamura, Ryoichi;Tohnai, Genki;Fujioka, Yusuke;Ishigaki, Shinsuke;Udagawa, Tsuyoshi;Izumi, Yuishin;Morita, Mitsuya;Kano, Osamu;Oda, Masaya;Sone, Takefumi;Okano, Hideyuki;Atsuta, Naoki;Katsuno, Masahisa;Okada, Yohei;Sobue, Gen
关键词：
肉瘤融合蛋白 (FUS) 是肌萎缩侧索硬化症 (ALS) 中的一种致病性 RNA 结合蛋白。我们之前报道过 FUS 可以稳定突触 Ras-GTP 酶激活蛋白 1 (Syngap1) mRNA 的 3' 非翻译区 (UTR) 并维持脊柱成熟。为了阐明这一机制在 ALS 患者中的病理作用，我们在日本多中心队列的 807 名 ALS 患者中的 7 名（4 名男性和 3 名女性）的 FUS 结合位点中鉴定出了 SYNGAP1 3'UTR 变异 rs149438267。具有 SYNGAP1 变体的人诱导多能干细胞 (hiPSC) 衍生的运动神经元表现出异常剪接、异构体 α1 水平增加和异构体 γ 水平降低，从而导致树突棘损失。此外，SYNGAP1 变体过度招募 FUS 和异质核核糖核蛋白 K (HNRNPK)，而阻断 HNRNPK 的反义寡核苷酸 (ASO) 会改变异常剪接并改善树突棘损失。这些数据表明，RNA 结合蛋白（尤其是 HNRNPK）的过度募集以及 SYNGAP1 亚型的变化对于运动神经元中脊柱的形成至关重要。意义陈述 目前尚不清楚哪些 RNA 导致肌萎缩侧索硬化症 (ALS) 的发病机制。我们之前报道过，肉瘤中的融合蛋白 (FUS) 是 ALS 中的一种致病性 RNA 结合蛋白，可稳定突触 Ras-GTP 酶激活蛋白 1 (Syngap1) mRNA 的 3' 非翻译区 (UTR)，并维持树突棘成熟。为了阐明这种机制对于 ALS 是否至关重要，我们在 FUS 结合位点鉴定了 SYNGAP1 3'UTR 变体 rs149438267。具有 SYNGAP1 变体的人诱导多能干细胞 (hiPSC) 衍生的运动神经元表现出异常剪接，导致树突棘丢失以及 FUS 和异质核糖核蛋白 K (HNRNPK) 的过度募集。我们发现树突棘损失是由于 RNA 结合蛋白的过度募集造成的，这为未来探索 ALS 相关 RNA 结合蛋白奠定了基础。
Fused in sarcoma (FUS) is a pathogenic RNA-binding protein in amyotrophic lateral sclerosis (ALS). We previously reported that FUS stabilizes Synaptic Ras-GTPase activating protein 1 (Syngap1) mRNA at its 3′ untranslated region (UTR) and maintains spine maturation. To elucidate the pathologic roles of this mechanism in ALS patients, we identified the SYNGAP1 3′UTR variant rs149438267 in seven (four males and three females) out of 807 ALS patients at the FUS binding site from a multicenter cohort in Japan. Human-induced pluripotent stem cell (hiPSC)-derived motor neurons with the SYNGAP1 variant showed aberrant splicing, increased isoform α1 levels, and decreased isoform γ levels, which caused dendritic spine loss. Moreover, the SYNGAP1 variant excessively recruited FUS and heterogeneous nuclear ribonucleoprotein K (HNRNPK), and antisense oligonucleotides (ASOs) blocking HNRNPK altered aberrant splicing and ameliorated dendritic spine loss. These data suggest that excessive recruitment of RNA-binding proteins, especially HNRNPK, as well as changes in SYNGAP1 isoforms, are crucial for spine formation in motor neurons. SIGNIFICANCE STATEMENT It is not yet known which RNAs cause the pathogenesis of amyotrophic lateral sclerosis (ALS). We previously reported that Fused in sarcoma (FUS), a pathogenic RNA-binding protein in ALS, stabilizes synaptic Ras-GTPase activating protein 1 (Syngap1) mRNA at its 3′ untranslated region (UTR) and maintains dendritic spine maturation. To elucidate whether this mechanism is crucial for ALS, we identified the SYNGAP1 3′UTR variant rs149438267 at the FUS binding site. Human-induced pluripotent stem cell (hiPSC)-derived motor neurons with the SYNGAP1 variant showed aberrant splicing, which caused dendritic spine loss along with excessive recruitment of FUS and heterogeneous nuclear ribonucleoprotein K (HNRNPK). Our findings that dendritic spine loss is because of excess recruitment of RNA-binding proteins provide a basis for the future exploration of ALS-related RNA-binding proteins.