Factor VIII (FVIII) is the protein deficient or functionally defective in hemophilia A, an X chromosome-linked bleeding disorder affecting 1/5,000 males. To avoid significant morbidity and mortality, patients are treated by protein replacement with recombinant-derived FVIII produced in mammalian cells. Although recombinant FVIII (rFVIII) has significantly reduced the risk of virus infection, treatment is still problematic due to the high cost to manufacture rFVIII, shortage of supply, limited access to peripheral veins, and development of inhibitory antibodies. Our previous studies demonstrated that FVIII production in mammalian cells is limited due to inefficient folding and transport through the early secretory pathway. The long-term goal of the proposed research is to elucidate key mechanisms that limit FVIII secretion in order to increase the production of rFVIII for treatment of hemophilia A. We will test the following three hypotheses (*): * FVIII secretion is limited by protein aggregation, protein chaperone interactions, and oxidative stress.
Specific Aim 1 : To define the chaperone interactions which regulate FVIII aggregation, folding, and trafficking. *FVIII synthesis activates an adaptive cellular response that facilitates FVIII folding and secretion.
Specific Aim 2 : To unravel the molecular mechanism(s) by which IRE11/XBP1 and ATF61 promote proper FVIII folding and trafficking within the early secretory pathway. * Productive FVIII folding and trafficking requires interaction with the cargo receptor LMAN1/MCFD2, through asparagine-linked glycans within the B domain.
Specific Aim 3 : To elucidate the requirement for LMAN1/MCFD2 in FVIII secretion. The approach will use a combination of biochemical, cell biological, and novel genetic mouse models to dissect fundamental processes that direct and limit FVIII trafficking through the secretory pathway. The information will be vital to the future development of improved gene therapy protocols for hemophilia A. The findings will provide fundamental mechanistic insight into the processes that regulate protein folding and trafficking within the secretory pathway. These studies will have much broader impact toward understanding the etiology of many genetic and acquired diseases of protein misfolding and the discoveries may uncover novel therapeutic avenues for multiple disease states.

Public Health Relevance

FVIII is the protein deficient in hemophilia A. Although protein replacement with recombinant FVIII is the preferred treatment, it is very costly. As FVIII production is limited due to protein misfolding, our studies to elucidate mechanisms that improve FVIII folding that should increase production of FVIII. The findings will impact all cell/gene therapy approaches to treat hemophilia A.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
Project #
Application #
Study Section
Hemostasis and Thrombosis Study Section (HT)
Program Officer
Link, Rebecca P
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Sanford-Burnham Medical Research Institute
La Jolla
United States
Zip Code
Ravindran, Rajesh; Loebbermann, Jens; Nakaya, Helder I et al. (2016) The amino acid sensor GCN2 controls gut inflammation by inhibiting inflammasome activation. Nature 531:523-527
Yang, Liu; Li, Shaohua; Miao, Linqing et al. (2016) Rescue of Glaucomatous Neurodegeneration by Differentially Modulating Neuronal Endoplasmic Reticulum Stress Molecules. J Neurosci 36:5891-903
Wang, Shiyu; Park, Shuin; Kodali, Vamsi K et al. (2015) Identification of protein disulfide isomerase 1 as a key isomerase for disulfide bond formation in apolipoprotein B100. Mol Biol Cell 26:594-604
Kohl, Susanne; Zobor, Ditta; Chiang, Wei-Chieh et al. (2015) Mutations in the unfolded protein response regulator ATF6 cause the cone dysfunction disorder achromatopsia. Nat Genet 47:757-65
Xi, Y; Garshott, D M; Brownell, A L et al. (2015) Cantharidins induce ER stress and a terminal unfolded protein response in OSCC. J Dent Res 94:320-9
Han, Jaeseok; Song, Benbo; Kim, Jiun et al. (2015) Antioxidants Complement the Requirement for Protein Chaperone Function to Maintain ?-Cell Function and Glucose Homeostasis. Diabetes 64:2892-904
Genereux, Joseph C; Qu, Song; Zhou, Minghai et al. (2015) Unfolded protein response-induced ERdj3 secretion links ER stress to extracellular proteostasis. EMBO J 34:4-19
D'Osualdo, Andrea; Anania, Veronica G; Yu, Kebing et al. (2015) Transcription Factor ATF4 Induces NLRP1 Inflammasome Expression during Endoplasmic Reticulum Stress. PLoS One 10:e0130635
Hassler, Justin R; Scheuner, Donalyn L; Wang, Shiyu et al. (2015) The IRE1?/XBP1s Pathway Is Essential for the Glucose Response and Protection of ? Cells. PLoS Biol 13:e1002277
Zhou, Alex-Xianghua; Wang, Xiaobo; Lin, Chyuan Sheng et al. (2015) C/EBP-Homologous Protein (CHOP) in Vascular Smooth Muscle Cells Regulates Their Proliferation in Aortic Explants and Atherosclerotic Lesions. Circ Res 116:1736-43

Showing the most recent 10 out of 140 publications