How does FVIII Expression Induce Cell Death

错误折叠的蛋白质在内质网(ER)内堆积是导致细胞 导致疾病发病机制的死亡。尽管蛋白质在不同的环境中表现出氧化损伤 在疾病状态下，蛋白质错误折叠和氧化应激之间的关系还没有被探索。至 阐明蛋白质错误折叠与氧化应激的关系，我们已经分析了 凝血因子VIII(FVIII)，在血友病A中缺乏的一种蛋白质，容易错误折叠。虽然 血友病A患者通过频繁输注血浆来源或重组来源的FVIII进行治疗， 但仍然存在重大限制。人们希望FVIII基因疗法能够解决这些问题。不幸的是， 有限的临床研究还没有证明FVIII在治疗水平上的表达。在细胞水平上 由于蛋白质在内质网中的错误折叠和滞留，FVIII的表达受到限制。因此，FVIII 表达通过细胞内信号通路诱导内质网应激反应基因转录 被称为未折叠蛋白反应(UPR)。我们的研究表明，慢性未解决的 内质网中未折叠的FVIII的积聚导致细胞以一种需要促凋亡的方式进行凋亡 转录因子C/EBP同源蛋白CHOP。最近，我们已经证明了FVIII 错误折叠会导致氧化应激，并引发炎症反应。此外，氧化应激 导致FVIII错误折叠，从而在FVIII错误折叠和氧化应激之间造成恶性循环。 深刻地说，抗氧化治疗可以减少氧化应激，改善FVIII的分泌，并减少 细胞凋亡。这些发现为拟议的研究提供了基础，以阐明FVIII是如何诱导 细胞凋亡、氧化和炎症反应途径。这些研究将检验Fviii的假设 由于这些应激反应的诱导，表达受到限制。研究将测试干预是否会 预防这些毒性反应可能会提高FVIII基因治疗血友病A的疗效。 这项拟议研究的发现将为阐明蛋白质如何 内质网的错误折叠是细胞死亡反应的信号，应该会对一些疾病状态产生影响 与内质网应激有关。

Accumulation of misfolded protein within the endoplasmic reticulum (ER) is a central event leading to cell death that contributes to disease pathogenesis. Although proteins exhibit oxidative damage in diverse disease states, the relationship between protein misfolding and oxidative stress has not been explored. To elucidate the relationship between protein misfolding and oxidative stress, we have analyzed expression of the clotting factor VIII (FVIII), the protein deficient in hemophilia A and prone to misfolding. Although hemophilia A patients are treated by frequent infusions of plasma-derived or recombinant-derived FVIII, significant limitations remain. It is hoped that FVIII gene therapy will solve these problems. Unfortunately, limited clinical studies have not demonstrated expression of FVIII at therapeutic levels. At the cellular level FVIII expression is limited due to protein misfolding and retention in the ER. As a consequence, FVIII expression induces transcription of ER stress response genes, through an intracellular signaling pathway called the unfolded protein response (UPR). Our studies have shown that the chronic unresolved accumulation of unfolded FVIII in the ER leads to apoptosis in a manner that requires the proapoptotic transcription factor C/EBP homologous protein CHOP. Recently, we have demonstrated that FVIII misfolding causes oxidative stress and induces an inflammatory response. In addition, oxidative stress causes FVIII misfolding, thereby creating a vicious cycle between FVIII misfolding and oxidative stress. Profoundly, anti-oxidant treatment to reduce oxidative stress improves FVIII secretion and reduces apoptosis. These findings provide the basis of the proposed research to elucidate how FVIII induces apoptotic, oxidative, and inflammatory response pathways. The studies will test the hypothesis that FVIII expression is limited due to induction of these stress responses. Studies will test whether intervention to prevent these toxic responses may improve therapeutic efficacy in FVIII gene delivery for hemophilia A. The findings from the proposed studies will provide fundamental new insights toward elucidating how protein misfolding in the ER signals a cell death response and should have impact on a number of disease states associated with ER stress.