Journal of Blood Disorders & Transfusion

Optimizing lipid nanotechnologies for structural and functional studies of membrane-bound factor VIII and the FVIIIa-FIXa complex

5^th World Hematologists Congress

August 18-19, 2016 London, UK

Svetla Stoilova-McPhie

University of Texas Medical Branch, USA

Posters & Accepted Abstracts: J Blood Disord Transfus

Abstract:

The processes localized to biological membranes are of great interest for scientific investigation as they are the primary targets for pharmaceutical interventions. Understanding the detailed mechanism and regulation of these processes requires the investigation of the functional structure of the membrane-bound proteins involved in these processes. We are developing lipid nanotechnologies such as lipid nanodiscs (ND) and nanotubes (LNT) that resemble the activated platelet surface during the propagation phase of coagulation and will allow structural and functional studies of membrane-associated blood coagulation factor VIII (FVIII) and its complex with Factor IXa (FIXa). The proposed lipid nanotechnologies will allow investigating how the membrane environment modulates the function of membrane-associated FVIII and the FVIIIa-FIXa complex both in-vitro and in-vivo. We have resolved an intermediate structure (~2 nm) for both recombinant human (h) and porcine (p) FVIII bound to phosphatidylserine (PS) rich LNT. Our results show that the two proteins both approved as therapeutics for the treatment of Hemophilia A; form dimers when membrane bound suggesting a dimeric organization for the membrane-bound FVIIIa-FIXa complex. We have also resolved an intermediate structure for recombinant pFVIII bound to PS-ND; further testing the pFVIII-ND complexes in FVIII deficient (FVIIIKO) mice showed a notable improvement of the clotting time after tail snip. Developing lipid nanotechnologies suitable for structural and functional studies of membrane-associated coagulation proteins will advance our understanding of the relationship between macromolecular organization and function required for the design of new therapeutics to regulate effectively blood hemostasis at the FVIIIa-FIXa complex level.

Biography :

Email: svmcphie@utmb.edu