OC 55.5 - Safe Nucleic acid Inhibitors That Show Protection Against Immunothrombosis in Sepsis

Tuesday, June 27, 2023

11:45 – 12:00 ET

Room: 510

Session Available As: On-Demand

Co-Author(s)

SV

Sreeparna Vappala, PhD (she/her/hers)

Researcher
University of British Columbia
Winnipeg, Manitoba, Canada

Co-Author(s)

AR

Alina Reicherz

Research fellow
The Stone Centre at Vancouver General Hospital, Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada.
Vancouver, British Columbia, Canada
CL

Chanel La

Researcher
Centre for Blood Research, University of British Columbia
Vancouver, British Columbia, Canada
Haifeng Ji

Postdoctor
University of British Columbia
Vancouver, British Columbia, Canada
SA

Srinivas Abbina

Researcher
Centre for Blood Research, University of British Columbia
Vancouver, British Columbia, Canada
MK

Manu Thomas Kalathottukaren

Researcher
Centre for Blood Research, University of British Columbia
Vancouver, British Columbia, Canada
MD

Matthew Drayton

Research technician
Centre for Blood Research, University of British Columbia
Vancouver, British Columbia, Canada
RH

Roman Herout

Research fellow
The Stone Centre at Vancouver General Hospital, Department of Urologic Sciences, University of British Columbia
Vancouver, British Columbia, Canada
IC

Irina Chafeeva

Research technician
Centre for Blood Research, University of British Columbia
Vancouver, British Columbia, Canada
CC

Cedric Carter

Associate Professor Emeritus
Centre for Blood Research, University of British Columbia
Vancouver, British Columbia, Canada
James H. Morrissey, PhD

Professor
Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
Ann Arbor, Michigan, United States
Edward M Conway, MD, PhD

Professor
Centre for Blood Research, University of British Columbia
Vancouver, British Columbia, Canada
CH

Charles A Haynes

Professor
Michael Smith Laboratories, Chemical & Biological Engineering, University of British Columbia
Vancouver, British Columbia, Canada
DL

Dirk Lange

Associate Professor
The Stone Centre at Vancouver General Hospital, Department of Urologic Sciences, University of British Columbia
Vancouver, British Columbia, Canada

Presenting Author(s)

Jayachandran N. Kizhakkedathu, PhD (he/him/his)

Professor
Centre for Blood Research, University of British Columbia
Vancouver, British Columbia, Canada

Background: Nucleic acids (polyanionic molecules) including cell-free DNA, RNA, and the assembly of Neutrophil Extracellular Traps (NETs) are indicated as mediators of thrombosis. NETs are shown to promote Disseminated Intravascular Coagulation in sepsis. Targeting nucleic acids (NA) instead of key coagulation enzymes could potentially inhibit thrombosis and hyper-inflammation and organ damage and may lead to novel method treating this condition.

Aims: Our aim is to develop effective inhibitors to protect against immunothrombosis and organ damage in sepsis. We have screened a library of molecules (PNBIs) and identified safe and effective candidates that target polyanionic nucleic acids and reverse their accelerated blood clotting potential in vitro and in vivo.

Methods: PNBIs are screened for inhibition of in vitro plasma clotting and thrombin generation triggered by nucleic acids (NA) and inhibition NA insertion in clots. The lead PNBIs are evaluated in a Cecal Ligation and Puncture (CLP) polymicrobial sepsis mouse model to study their protection against thrombosis and cytokine storm. Multi-dose administration of PNBI in mice was used to test the tolerance of PNBIs.

Results: The lead candidates were identified with optimal neutralization potential against NAs. PNBI showed reversal of NA triggered FXII activation and thrombin generation (Fig. 1). PNBIs inhibited the insertion of NAs to fibrin clot and prevented resistance to clot lysis. PNBIs, decreased thrombin generation, TAT complex and DNA concentration in CLP mice (Fig.2). Additionally, PNBIs reduced elevated levels of pro-inflammatory cytokines and is well tolerated by mice.

Conclusion(s): Our results demonstrate that PNBIs can reverse the procoagulant potential of NAs both in vitro and in vivo. Furthermore, it reduces the cytokine storm triggered by NETs in sepsis. By targeting polyanionic accelerators rather than coagulation enzymes, this strategy offers a pathway to develop safer antithrombotic agents in sepsis.

Learning Objectives:

To review the potential role of extracellular nucleic acids in immunothrombosis and DIC
Introduce new concepts in the design of nucleic acid binding molecules as immunothrombosis inhibitors
To review the results from in vitro screening studies, identification of lead candidates and their evaluation in a polymicrobial sepsis model