Alan E. Mast, M.D., Ph.D.

Alan E. Mast, M.D., Ph.D.

Investigator
  Blood Research Institute
  BloodCenter of Wisconsin

Associate Medical Director, Medical Services
  BloodCenter of Wisconsin

Associate Professor, Department of Pathology
  Medical College of Wisconsin

M.D., Ph.D., Duke University, 1991

Selected Publications
Grant Support
Invited Lectures
Laboratory Staff
Contact Information

Research Interests
The blood vessel contains several anticoagulant proteins that prevent the formation of blood clots within the blood vessel.  The work in our laboratory is currently focused on one of these proteins called Tissue Factor Pathway Inhibitor or TFPI.  TFPI is a trivalent Kunitz-type serine proteinase inhibitor that simultaneously inhibits factor Xa and factor VIIa immediately following activation of factor X by the factor VIIa/tissue factor catalytic complex.  Thus, TFPI inhibits very early stages of the blood coagulation system.  Its functional importance is evident in that a genetic deficiency of TFPI has not been described in humans, and genetically altered mice that do not make TFPI die in utero. 

One interest of our laboratory is the mechanisms for expression of TFPI on the cell surface.  Structurally, TFPI appears to be a secreted protein, containing a leader sequence at its N-terminus, but not a C-terminal GPI-anchor attachment sequence or transmembrane spanning region.  However, endothelial cells make TFPI and process it so that it becomes associated with the cell surface.  It appears that TFPI associates with the cell surface by tightly binding to co-receptor that is attached to the cell surface through a GPI-anchor.  We have made a cell line that does not make GPI-anchored proteins.  In this cell line, TFPI is degraded within the cell with no TFPI present on the cell surface and very little secreted into the culture medium.  Thus, it appears that association with a GPI-anchored protein is essential for proper processing of TFPI by the cell.  We are interested is studying how TFPI traffics through the cell.  We want to know where and how it associates with the GPI-anchored protein and if there are any signal sequences in TFPI that target it to a specific cellular compartment where it associates with this GPI-anchored protein.  We are also interested in identifying GPI-anchored proteins that bind TFPI and act as the co-receptor for cell surface attachment.

We are studying how the cell surface expression of TFPI is altered in different diseases.  Paroxysmal nocturnal hemoglobinuria (PNH) is a disease that results from formation of blood cells that do not have GPI-anchored proteins.  Patients with this disease have a very strong tendency to form blood clots.  We want to know if this is due to low amounts of TFPI.  We also want to understand how cellular expression of TFPI changes in women taking oral contraceptives.  It appears that plasma TFPI levels are decreased in these women, possibly accounting for the increased incidence of blood clots observed in these women.  We are developing methods to measure TFPI on blood cells.  We hope that by using this type of assay to measure cell associated TFPI, rather than just measuring TFPI in the blood plasma, we will make new discoveries about how it changes in different disease states.

Another area of interest in our laboratory is the biochemical investigation of the inhibition of blood coagulation reactions by TFPI.  We are comparing the inhibitory properties of soluble and cell associated TFPI.  We are investigating the biochemical interactions of TFPI with different blood coagulation factors to understand potential anticoagulant properties of TFPI other than inhibition of factors VIIa and Xa. 

Grant Support
R01-HL68835-01A1, Tissue Factor Pathway Inhibitor Binding Proteins on Endothelium (8/02-7/06)
AHA 0540046N, Intracellular Trafficking of Tissue Factor Pathway Inhibitor (1/05-12/09)
NHLBI-HB-0-07, Retrovirus Epidemiology Donor Study-II (REDS-II) (PI: JL Gottschall) (9/04-8/09)

Invited Lectures (Selected)

• “Regulation of Blood Coagulation by Cell Surface Associated Tissue Factor Pathway Inhibitor"  Visiting Professor, University of California, Irvine (3/8/02). 
• "Association of TFPI with Biological Surfaces"  First Symposium on Hemostasis with Special Focus on Factor VIIa and Tissue Factor.  University of North Carolina, Chapel Hill (4/6/02).
• “Structure Function of TFPI” International Society of Thrombosis and Haemostasis 49th Annual Meeting.  Birmingham, UK (7/14/03).

Laboratory Staff

Susan Maroney, D.V.M., Ph.D.	susan.maroney@bcw.edu	Research Scientist II
Josephine Ferrel	josephine.ferrel@bcw.edu	Research Technologist

Employment Opportunities
If opportunities are available, they will be listed on the Employment page.

Contact Information
Phone: (414) 937-6310
Fax: (414) 937-6284
E-mail: alan.mast@bcw.edu