How does FVIII Expression Induce Cell Death

错误折叠的蛋白质在内质网（ER）内的积累是导致细胞凋亡的中心事件。 导致疾病发病的死亡。虽然蛋白质在不同的细胞中表现出氧化损伤， 在疾病状态下，蛋白质错误折叠和氧化应激之间的关系尚未被探索。到 为了阐明蛋白质错误折叠和氧化应激之间的关系，我们分析了 凝血因子VIII（FVIII），血友病A中缺乏的蛋白质，易于错误折叠。虽然 血友病A患者通过频繁输注血浆来源的或重组来源的FVIII来治疗， 仍然存在重大的局限性。人们希望FVIII基因治疗能解决这些问题。不幸的是， 有限的临床研究尚未证明FVIII的表达处于治疗水平。在细胞水平上 由于蛋白质错误折叠和滞留在ER中，FVIII表达受到限制。因此，FVIII 表达通过细胞内信号通路诱导ER应激反应基因的转录 称为未折叠蛋白反应（UPR）。我们的研究表明，长期未解决的 未折叠的FVIII在ER中的积累以需要促凋亡因子的方式导致细胞凋亡。 转录因子C/EBP同源蛋白CHOP。最近，我们已经证明， 错误折叠引起氧化应激并诱导炎症反应。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形成恶性循环。 从根本上说，减少氧化应激的抗氧化治疗可改善FVIII分泌， 凋亡这些发现为阐明FVIII如何诱导 凋亡、氧化和炎症反应途径。这些研究将检验FVIII 由于这些应激反应的诱导，表达受到限制。研究将测试是否干预， 预防这些毒性反应可提高FVIII基因递送治疗血友病A的疗效。的 这项研究的结果将为阐明蛋白质是如何 ER中的错误折叠是细胞死亡反应的信号，并对许多疾病状态产生影响 与ER压力有关。

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.