Tanay Deepak
Pronouns:
Research Mentor(s): Karl Desch
Research Mentor School/College/Department: Pediatrics / Medicine
Program: UROP
Session: Session 4 (1:40pm – 2:30pm)
Authors: Karl Desch, Mary Underwood , Krista Golden, Tanay Deepak
Abstract
Deep vein thrombosis and pulmonary embolism, collectively defined as venous thromboembolism (VTE), are the third leading cause of cardiovascular death in the United States. Rare mutations in the stab-2 gene are found in patients with VTE. The STAB2 gene encodes stabilin-2, a transmembrane scavenger receptor that internalizes ligands from the circulation and targets them for degradation by the cell. Previous characterization has shown stabilin-2 to remove sugars from the circulation, however, no previous link to thrombosis had been made. We hypothesized that stabilin-2 removes procoagulant proteins that play a role in blood clotting and defective function of stabilin-2 may play an indirect role in thrombosis by regulating procoagulant protein levels. In this search, our lab recently identified novel ligands using a protein screen. We now aim to validate these findings and find which ligands link stabilin-2 to coagulation. In order to identify ligand interaction we first used flow cytometry. These ligands include heparin cofactor II, C4BPB, prothrombin, high molecular weight kininogen, and plasminogen. The ligands were fluorescently labeled and incubated with stabilin-2 and non-stabilin-2 expressing cells. Cells that bound to fluorescent ligands had an increased fluorescence. To further validate the interactions, cells were incubated with the fluorescently labeled ligands, permeabilized and stained for an endosomal marker. Cells were imaged using confocal microscopy to look for localization of the ligands within the cell endosomes. This method helped test whether the ligands were internalized by the stabilin-2 expressing cells. Using flow cytometry and confocal microscopy, all ligands except C4BPB were confirmed to interact with stabilin-2 expressing cells. These results suggest that mutations in the stab-2 gene may increase thrombosis risk through defective removal of procoagulant ligands such as prothrombin and high molecular weight kininogen. This project benefits the medical and broader scientific community as it helps with protein characterization that can be used to better diagnose and treat patients with deep vein thrombosis and other blood clotting related diseases.
