OC 45.1 - A genome-wide CRISPR-Cas9 knockout screen reveals FSP1 as the warfarin-resistant vitamin K reductase

Monday, June 26, 2023

14:45 – 15:00 ET

Room: 511

Session Available As: On-Demand

Co-Author(s)

DJ

Da-Yun Jin

Research Specialist
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States
XC

Xuejie Chen

Research Associate
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States
YL

Yizhou Liu

Graduate student
University of Queensland
Queensland, Queensland, Australia
CW

Criag Williams

Professor
University of Queensland, Australia
Queensland, Queensland, Australia
LP

Lars Pedersen

Director
NIEHS
Durham, North Carolina, United States
DS

Darrel Stafford

Professor
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States

Presenting Author(s)

Jian-Ke Tie, PhD

Research Associate Professor
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States

Background: Vitamin K is a vital micronutrient implicated in a variety of human diseases. Warfarin, a vitamin K antagonist, is the most commonly prescribed oral anticoagulant. Patients overdosed on warfarin can be rescued by administering high doses of vitamin K because of the existence of a warfarin-resistant vitamin K reductase (VKR). Despite the functional discovery of VKR over eight decades ago, the identity of VKR remained elusive.

Aims: Here, we report the identification of warfarin-resistant VKR.

Methods: We used a genome-wide CRISPR-Cas9 knockout screening with a novel vitamin K-dependent (VKD) apoptotic reporter cell line.

Results: We found that ferroptosis suppressor protein 1 (FSP1), a ubiquinone oxidoreductase, is the enzyme responsible for vitamin K reduction in a warfarin-resistant manner. FSP1 inhibitor that inhibited ubiquinone reduction and thus triggering cancer cell ferroptosis, displayed strong inhibition of VKD carboxylation. Intriguingly, dihydroorotate dehydrogenase, another ubiquinone-associated ferroptosis suppressor protein parallel to the function of FSP1, does not support VKD carboxylation.

Conclusion(s): These findings provide new insights into selectively controlling the physiological and pathological processes involving electron transfers mediated by vitamin K and ubiquinone.

Learning Objectives:

observe the importance of vitamin K-dependent carboxylation in blood coagulation
understand the rationale for generating vitamin K-dependent apoptosis reporter cell line for genome-wide CRISPR-Cas9 knockout screening
differentiate the function of FSP1 in vitamin K-dependent carboxylation and cancer cell ferroptosis