Project Summary
The long-term goal of our work is to identify genetic variants that suppress intravascular blood clotting
called thrombosis or venous thromboembolism (VTE). We previously use a genome wide mutation
screen in mice to identify 10 dominant genetic variants that suppressed lethal thrombosis. Several
of these mutations are in genes which, when mutated, enable mice with a lethal thrombosis genotype
to survive. Arl6ip5 is one such gene. This gene and its protein product, also known as JWA, Praf3
etc. has multiple putative cellular and organismal functions, overlapping with Actr2 (Arp2, part of the
Arp2/3 complex). Our central hypothesis is that Arl6ip5 deficiency affects thrombosis by altering
essential cellular functions via cytoskeletal and transcriptional pathways. These in turn affect platelet
reactivity, gene transcription, and the kinetics of thrombosis.
We will complete the Specific Aims of our project by performing assays on our genome edited mouse
model of Arl6ip5 deficiency. Specific AIM 1 will investigate the ability of complete Arl6ip5 deficiency
to increase thrombosis suppression relative to partial Arl6ip5 deficiency. We will also investigate the
effects of Arl6ip5 on tail bleeding and Rose Bengal induced arterial and venous thrombosis. Specific
AIM 2 experiments will probe Arl6ip5 deficient platelets for functional and transcriptional defects
using targeted platelet assays and platelet RNA sequencing. To follow up on the plasma activated
partial thrombosplastin time (APTT) defect we observed in Arl6ip5 deficient mice, we will perform
detailed studies on blood and plasma, including the measurement of coagulation factor levels and
liver RNA sequencing to determine the molecular genetic pathway leading to this effect. Both male
and female mice will be testing to ensure the rigor and thoroughness of our studies.
The completion of the proposed studies will provide the first evidence of the role Arl6ip5 gene
mutations play in regulating hemostasis. These questions are highly impactful to the mission of the
NIH because they provide critical information about the regulation of thrombi, a widespread killer
causing heart attacks, strokes, and VTE. Increased fundamental knowledge of this process could
provide better insights into preventative and therapeutic strategies. These studies will also be used
to train the next generation of cardiovascular researchers in the proper conduct of scientific studies,
preparing them for outstanding independent scientific careers in cardiovascular research. The
funding of this grant will further contribute to the outstanding training environment of the Oakland
University Department of Biological Sciences, which has been doing an outstanding job of
contributing scientists to graduate and postdoctoral training programs in cardiovascular research.