Study on PFN1 Pathobiology Using Rat Models

Profilin 1(PFN1)基因突变是肌萎缩侧索硬化症(ALS)的致病基因。PFN1已经成为 对它的生物学和最近的病理生物学进行了广泛的检查，但PFN1突变是如何导致疾病的 仍有待确定。了解疾病基因的关键一步是确定总体效应。 致病突变在系统和分子水平上对基因功能的影响。肌萎缩侧索硬化是一种神经系统疾病 因此，必须在脊椎动物身上确定致病突变对PFN1功能的总体影响 模型，因为人类中枢神经系统的复杂性不能在细胞或 无脊椎动物。一个有效的肌萎缩侧索硬化症动物模型应该至少满足三个标准： ALS的主要表型包括上下运动神经元进行性变性和 骨骼肌失神经萎缩；表现为ALS表型的中晚期，常见于 散发性和遗传性肌萎缩侧索硬化症；在野生型和突变型之间表现出不同的疾病表型 转基因株系。人类疾病的理想动物模型是基因敲击，在这种模型中，一种单一的致病因素 突变被引入到动物基因组中，因此致病突变在生理上表现出来 水平和内在模式，模拟观察到的 病人。由于通常用于模拟人类疾病的动物(即小鼠和大鼠)寿命较短(2-3 人类(平均80岁)，疾病基因在生理水平上的表达可能 不足以诱发全谱的疾病表型。因此，基因过度表达模型(即 转基因)常被用作研究遗传性疾病的敲门模型的替代品。要解开 致病突变对PFN1功能的总体影响，我们创造了符合条件的PFN1转基因大鼠 建立有效的ALS模型的标准，并建立了表达PFN1突变的PFN1敲击大鼠 它的内源位置。在检测的单个核苷酸中，敲门鼠与它们的野生型窝鼠不同。任何 在敲门鼠身上检测到的表型必须是引入的致病突变所致。使用PFN1 以转基因大鼠和敲击大鼠为补充模型，我们将确定致病的整体效果。 PFN1上的突变在系统和分子水平上发挥作用，揭示了 PFN1突变导致了这种疾病。我们的PFN1大鼠模型将是继SOD1之后第二个有效的ALS模型 转基因啮齿动物，从而满足ALS疾病机制和疾病研究的迫切需要 在一种模型中发现的治疗效果必须在其他模型中确定，以实现收敛和 不同ALS基因之间的差异，因为遗传性ALS揭示了趋同的疾病机制 模型将对散发性ALS有更好的预测。

Pathogenic mutation of profilin 1 (PFN1) is causative to amyotrophic lateral sclerosis (ALS). PFN1 has been examined extensively on its biology and recently on its pathobiology, but how PFN1 mutation causes the disease remains to be determined. A critical step towards understanding a disease gene is determining the overall effect of pathogenic mutation on the gene function at both systemic and molecular levels. ALS is a neurological disease and thus the overall effect of pathogenic mutation on PFN1 function must be determined in a vertebrate animal model because the complexity of the human central nervous system cannot be adequately simulated in cells or invertebrate animals. An effective animal model for ALS should meet at least three criteria: recapitulate the cardinal phenotypes of ALS including progressive degeneration of both upper and lower motor neurons and denervation atrophy of skeletal muscles; manifest the middle or late onset of ALS phenotypes that is common to sporadic and most inherited ALS; and display a differentiated disease phenotype between wild-type and mutant transgenic lines. An ideal animal model for human disease is gene knockin in which a single disease-causing mutation is introduced into the animal genome such that the pathogenic mutation is expressed at physiological levels and in intrinsic patterns, simulating the patterns and zygosities of gene expression that are observed in patients. As animals commonly used to model human diseases (i.e. mice and rats) have a shorter life span (2-3 years at maximum) than human (80 years on average), expression of a disease gene at physiological levels may not be sufficient to induce a full spectrum of disease phenotypes. Therefore, gene-overexpressing models (i.e. transgenics) are often used as the substitutes of knockin models for studying inherited diseases. To unravel the overall effect of pathogenic mutation on the PFN1 functions, we have created PFN1 transgenic rats that meet the criteria of effective ALS model and also have created PFN1 knockin rats that express PFN1 mutation from its endogenous locus. The knockin rats differ from their wildtype littermates in a single nucleotide examined. Any phenotypes detected in the knockin rats must result from the pathogenic mutation introduced. Using PFN1 transgenic and knockin rats as complementary models, we are going to determine the overall effect of pathogenic mutation on PFN1 function at both systemic and molecular levels, revealing the authentic mechanisms by which PFN1 mutation causes the disease. Our PFN1 rat models will be the second effective ALS model after SOD1 transgenic rodents and thus will meet the compelling need of ALS research in that disease mechanisms and therapeutic efficacies discovered in one model must be determined in the other models for the convergence and divergence among varying ALS genes because convergent disease mechanisms revealed in genetic ALS models will have a better prediction of sporadic ALS.