Investigating the Role of the Helicase, IGHMBP2, and the RIG-I-Like Receptor Pathway in Spinal Muscular Atrophy with Respiratory Distress Type 1 and Neuromuscular Development (SMARD1)

研究解旋酶、IGHMBP2 和 RIG-I 样受体通路在伴有 1 型呼吸窘迫的脊髓性肌萎缩症和神经肌肉发育 (SMARD1) 中的作用

• 批准号: 10682408
• 负责人: Sarah Holbrook
• 金额: $ 3.17万
• 依托单位: JACKSON LABORATORY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10682408
• 关键词: Binding Proteins; Biological Assay; Breeding; Categories; Cause of Death; Cell Death; Cells; Cessation of life; Charcot-Marie-Tooth Disease; Childhood; Clustered Regularly Interspaced Short Palindromic Repeats; DNA; Data; Degenerative Disorder; Detection; Development; Disease; Disease model; Dose; Double-Stranded RNA; Elements; Etiology; Fluorescent in Situ Hybridization; Future; Gene Expression; Gene Mutation; Genes; Genetic; Genetic Crosses; Hereditary Motor and Sensory Neuropathy Type I; Heterozygote; Human; Immune system; Immunoglobulin Genes; Immunoglobulins; Induced Mutation; Infection; Injections; Investments; Knock-out; Location; Longevity; Maintenance; Mediator; Modeling; Motor; Motor Neuron Disease; Motor Neurons; Mus; Mutant Strains Mice; Mutate; Mutation; Nerve Degeneration; Nerve Tissue; Neuropathy; Nuclear; Nuclear Export; Pathway interactions; Patients; Peripheral Nervous System Diseases; Phenotype; Play; Poly I-C; Proteins; Publishing; Quality Control; RNA; RNA Helicase; Rare Diseases; Receptor Signaling; Research; Research Project Grants; Respiratory distress; Ribonucleases; Ribosomes; Role; Route; Sensory; Series; Severities; Severity of illness; Spinal Cord; Spinal Diseases; Spinal Muscular Atrophy; Sudden infant death syndrome; Therapeutic; Tooth Diseases; Translations; Up-Regulation; Viral; Work; animal breeding; cell type; disease phenotype; helicase; motor neuron degeneration; mouse model; mutant; neural; neurodevelopment; neuromuscular; neuron loss; novel; postnatal; prevent; receptor; response; targeted treatment; therapeutic target; transcriptome sequencing; tripolyphosphate; young adult

PROJECT ABSTRACT Deleterious recessive mutations in the immunoglobulin h mu-binding protein 2 gene (IGHMBP2) create a spectrum of motor neuron diseases (MNDs) ranging from the less severe young adult onset motor and sensory neuropathic disease, Charcot-Marie-Tooth disease type 2S (CMT2S), to the severe and often fatal young childhood disease, Spinal Muscular Atrophy with Respiratory Distress type 1 (SMARD1). IGHMBP2 mutations have also been associated with Sudden Infant Death Syndrome (SIDS). Due to the rarity of these diseases, not much research has been invested into possible therapeutics, let alone the role IGHMBP2 plays in causing the phenotype. IGHMBP2 is thought to encode a DNA/RNA helicase with low processivity. It is ubiquitously expressed at low levels throughout the body, with gonadal and nervous tissue having the highest expression. It is also believed to have a role in translation because of its association with ribosomes. Through the creation of several mouse models representing the spectrum of disease found in human patients, we have made strides in understanding that IGHMBP2 plays a role not only in these diseases, but in neuromuscular development/maintenance. We recently performed RNA sequencing on our severe SMARD1 and CMT2S models and found that the immune system RIG-I-like receptor (RLR) pathway is highly upregulated in the spinal cords of these mice. This pathway is associated with the detection of typically viral double-stranded RNA and causes eventual death of the infected cell via RNase L. We have also conducted studies on MND mouse models with deleterious recessive mutations in the nuclear export mediator factor-encoding gene Nemf. In these mice, we see a similar spectrum of disease severity. The NEMF protein is better known for its role in ribosome quality control. In our RNAseq analysis of the spinal cords of our mutated Nemf mice, we saw a similar upregulation of the RLR pathway. We also bred mice to be heterozygous for mutations in both Nemf and Ighmbp2. While a heterozygous phenotype is not typically seen for each mutated gene alone, these double heterozygous mutants showed a severe MND phenotype. This suggests that these mutations impact the same pathway. I hypothesize that dysfunctional IGHMBP2 and/or a decrease in IGHMBP2 causes certain RNA products associated with neural development/maintenance to build up, triggering the RLR pathway and causing death of the motor neurons. This study will determine if the RLR pathway has a reactive, ameliorative, or detrimental effect on neuromuscular degeneration. This study opens a novel category of MNDs associated with the RLR pathway. I propose a series of genetic crosses associated with knock-outs of RLR in addition to MND mutations. I also propose using single nuclear RNAseq and RNAscope, a single cell fluorescent in-situ hybridization assay, on the spinal cords of Ighmbp2 and Nemf mutant mice to determine the origin of the RLR signal.

项目摘要 免疫球蛋白 h mu 结合蛋白 2 基因 (IGHMBP2) 中的有害隐性突变会产生 运动神经元疾病 (MND) 范围从不太严重的年轻人发病的运动和感觉疾病 神经病，2S 型夏科-马里-图思病 (CMT2S)，对年轻人造成严重且往往致命 儿童疾病，脊髓性肌萎缩症伴呼吸窘迫 1 型 (SMARD1)。 IGHMBP2突变 也与婴儿猝死综合症（SIDS）有关。由于这些疾病的罕见性， 已经对可能的治疗方法进行了大量研究，更不用说 IGHMBP2 在引起 表型。 IGHMBP2 被认为编码低持续合成能力的 DNA/RNA 解旋酶。它无处不在 在全身表达量较低，其中性腺和神经组织表达量最高。它 由于其与核糖体的关联，也被认为在翻译中发挥作用。通过创建 几种代表人类患者疾病谱的小鼠模型，我们在这方面取得了长足进步 了解 IGHMBP2 不仅在这些疾病中发挥作用，而且在神经肌肉疾病中发挥作用 开发/维护。我们最近对严重的 SMARD1 和 CMT2S 进行了 RNA 测序 模型并发现免疫系统 RIG-I 样受体 (RLR) 通路在脊髓中高度上调 这些老鼠的绳索。该途径与典型病毒双链 RNA 的检测相关 通过 RNase L 导致受感染细胞最终死亡。我们还对 MND 小鼠模型进行了研究 核输出介导因子编码基因 Nemf 发生有害隐性突变。在这些小鼠中， 我们看到了类似的疾病严重程度。 NEMF 蛋白因其在核糖体质量中的作用而闻名 控制。在我们对突变 Nemf 小鼠脊髓进行 RNAseq 分析时，我们发现了类似的上调 RLR途径。我们还培育出 Nemf 和 Ighmbp2 突变杂合的小鼠。虽然一个 杂合表型通常不会单独针对每个突变基因出现，这些双杂合突变体 表现出严重的 MND 表型。这表明这些突变影响相同的途径。我假设 IGHMBP2 功能失调和/或 IGHMBP2 减少会导致某些与 神经发育/维持建立，触发 RLR 通路并导致运动死亡 神经元。这项研究将确定 RLR 通路是否对 神经肌肉变性。这项研究开辟了与 RLR 通路相关的 MND 的新类别。我 提出了一系列与 RLR 敲除以及 MND 突变相关的基因杂交。我也 建议使用单核 RNAseq 和 RNAscope（一种单细胞荧光原位杂交测定） Ighmbp2 和 Nemf 突变小鼠的脊髓以确定 RLR 信号的起源。