Targeting TNFα produced by astrocytes expressing amyotrophic lateral sclerosis-linked mutant fused in sarcoma prevents neurodegeneration and motor dysfunction in mice.
Targeting TNFα produced by astrocytes expressing amyotrophic lateral sclerosis-linked mutant fused in sarcoma prevents neurodegeneration and motor dysfunction in mice.
复制标题
靶向表达融合在肉瘤中的肌萎缩侧索硬化相关突变体的星形胶质细胞产生的TNFα可预防小鼠神经变性和运动功能障碍
作者：
导致肌萎缩侧索硬化症（ALS）（一种渐进性致死性运动神经元疾病）的基因突变通常存在于广泛表达的基因中。除了运动神经元内的直接缺陷外，越来越多的证据表明，非神经元细胞的功能障碍也是疾病的重要驱动因素。之前，我们证明了融合在肉瘤（FUS）中的DNA/RNA结合蛋白的突变通过激活NF-κB通路和释放促炎细胞因子TNFα在体外诱导星形胶质细胞的神经毒性表型。在这里，我们开发了一种脊髓内注射模型，以测试ALS致病FUSR 521 G变体（mtFUS）的星形胶质细胞特异性表达是否会导致体内神经元损伤。我们发现星形胶质细胞中限制性表达mtFUS足以诱导脊髓运动神经元死亡，通过上调TNFα导致运动缺陷。我们进一步证明TNFα是一个关键的毒性分子，因为TNFα敲除动物中mtFUS的表达不会诱导致病性变化。因此，在mtFUS转导的动物中，给予TNFα中和抗体可预防神经变性和运动功能障碍。总之，这些研究加强了星形胶质细胞导致ALS疾病的证据，并首次建立了FUS-ALS星形胶质细胞在体内诱导运动神经元的致病性变化。我们的工作确定了TNFα是mtFUS-星形胶质细胞毒性的关键驱动因素，并证明了靶向TNFα减轻运动神经元功能障碍和死亡的治疗成功。最终，通过定义并随后靶向这种毒性机制，我们提供了一种可行的FUS-ALS特异性治疗策略，该策略也可适用于FUS活性和细胞定位经常受到干扰的散发性ALS。通过在小鼠脊髓星形胶质细胞中表达肉瘤融合突变体（FUS）蛋白，我们观察了导致运动异常的病理变化。我们确定TNFα是真正的毒性来源，并证明了治疗靶向TNFα的可行性。
Genetic mutations that cause amyotrophic lateral sclerosis (ALS), a progressively lethal motor neuron disease, are commonly found in ubiquitously expressed genes. In addition to direct defects within motor neurons, growing evidence suggests that dysfunction of non‐neuronal cells is also an important driver of disease. Previously, we demonstrated that mutations in DNA/RNA binding protein fused in sarcoma (FUS) induce neurotoxic phenotypes in astrocytes in vitro, via activation of the NF‐κB pathway and release of pro‐inflammatory cytokine TNFα. Here, we developed an intraspinal cord injection model to test whether astrocyte‐specific expression of ALS‐causative FUSR521G variant (mtFUS) causes neuronal damage in vivo. We show that restricted expression of mtFUS in astrocytes is sufficient to induce death of spinal motor neurons leading to motor deficits through upregulation of TNFα. We further demonstrate that TNFα is a key toxic molecule as expression of mtFUS in TNFα knockout animals does not induce pathogenic changes. Accordingly, in mtFUS‐transduced animals, administration of TNFα neutralizing antibodies prevents neurodegeneration and motor dysfunction. Together, these studies strengthen evidence that astrocytes contribute to disease in ALS and establish, for the first time, that FUS‐ALS astrocytes induce pathogenic changes to motor neurons in vivo. Our work identifies TNFα as the critical driver of mtFUS‐astrocytic toxicity and demonstrates therapeutic success of targeting TNFα to attenuate motor neuron dysfunction and death. Ultimately, through defining and subsequently targeting this toxic mechanism, we provide a viable FUS‐ALS specific therapeutic strategy, which may also be applicable to sporadic ALS where FUS activity and cellular localization are frequently perturbed. By expressing mutant fused in sarcoma (FUS) protein in mouse spinal cord astrocytes, we observe pathogenic changes leading to motor abnormalities. We identify TNFα as a bona fide source of toxicity and demonstrate the feasibility of targeting TNFα therapeutically.