OC 55.1 - Balance between neutrophil extracellular trap formation and DNase activity in COVID-19 patients

Tuesday, June 27, 2023

10:45 – 11:00 ET

Room: 510

Session Available As: On-Demand

Presenting Author(s)

Geoffrey Garcia, PharmD (he/him/his)

PhD Student
University of Bordeaux, INSERM UMR 1034, Biology of cardiovascular diseases, Pessac, France
Bordeaux, Aquitaine, France

Co-Author(s)

SL

Sylvie Labrouche-Colomer

Assistant Professor
University of Bordeaux, INSERM UMR 1034, Biology of cardiovascular diseases, Pessac, France
Bordeaux, Aquitaine, France
AD

Alexandre Duvignaud

Assistant Professor
INSERM UMR 1219, Bordeaux Population Health Research Centre, Bordeaux, France
Bordeaux, Aquitaine, France
EC

Etienne Clequin

M.D.
CNRS, UMR5164 ImmunoConcEpT, Bordeaux University, Bordeaux, France
Bordeaux, Aquitaine, France
CD

Charles Dussiau

Assistant
University of Bordeaux, INSERM UMR 1034, Biology of cardiovascular diseases, Pessac, France
Pessac, Aquitaine, France
David-Alexandre TREGOUET, PhD (he/him/his)

Senior Investigator
Bordeaux Population Health research center - INSERM UMR1219
Bordeaux, Aquitaine, France
DM

Denis Malvy

Professor
INSERM UMR 1219, Bordeaux Population Health Research Centre, Bordeaux, France.
Bordeaux, Aquitaine, France
RP

Renaud Prével

M.D.
Univ Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Inserm UMR 1045, F-33000 Bordeaux, France
Bordeaux, Aquitaine, France
JG

Julien Goret

Assistant Professor
CNRS, UMR5164 ImmunoConcEpT, Bordeaux University, Bordeaux, France
Bordeaux, Aquitaine, France
MM

Maria Mamani-Matsuda

Professor
CNRS, UMR5164 ImmunoConcEpT, Bordeaux University, Bordeaux, France
Bordeaux, Aquitaine, France
AD

Antoine Dewitte

M.D.
CNRS, UMR5164 ImmunoConcEpT, Bordeaux University, Bordeaux, France
Bordeaux, Aquitaine, France
CJ

Chloé James

Professor
University of Bordeaux, INSERM UMR 1034, Biology of cardiovascular diseases, Pessac, France
Pessac, Aquitaine, France

Background: Immunothrombosis is increased in severe COVID-19, and potentially involved in its pathogenesis but the mechanisms explaining this deregulation are currently not understood. We hypothesized that decreased DNase activity was associated with increased NETosis and clinical worsening.

Aims: We aimed to compare the balance between NETs and DNase activity according to COVID-19 severity and investigate the mechanisms responsible for the imbalance between NETosis and DNase activity.

Methods: We studied 93 non-severe (oupatients), 27 severe (hospitalized) and 37 critical COVID-19 patients from COLCOV19-BX and COVERAGE studies. We quantified NET markers (MPO-DNA, H3Cit, H3cit-DNA), total DNase activity and the levels of DNase 1 and DNase1L3 proteins in plasmas from the 157 patients. In the 54 patients that were hospitalized, we sequenced DNase1 and DNase1L3 genes and used flow cytometry to quantify the numbers of plasmacytoid dendritic cell (pDC) and dendritic cells (DC) among peripheral blood mononuclear cells. Lastly, we analyzed scRNAseq public data from COVID-19 patients (PMID: 33879890).

Results: Plasma NET markers were higher in the most severe patients while DNase activity was lower. Critical patients showed decreased level of DNase 1 & 1L3 proteins compared to severe patients. We did not find any recurrent mutations in DNase1 and DNase1L3 that was associated with decreased amount of DNase1 or DNase1L3. We observed a quantitative defect of DC and pDCs in critical patients. Besides, analysis of public scRNaseq data revealed an inverse correlation between DNase1L3 RNA expression in pDC and disease severity.

Conclusion(s): Altogether, our study shows that severe and critical COVID-19 is associated with an imbalance between NETs and DNase activity, with decreased amount of DNase 1 and DNase1L3. We speculate that the defect in DNase1L3 may be due to a defect in DCs and pDCs. Early identification of patients with NETosis imbalance could allow administration of targeted therapies, such as DNase, to prevent clinical worsening.

Learning Objectives:

Upon completion, participant will be able to argue on NET accumulation during COVID-19.
Upon completion, participant will be able to raise hypotheses explaining a defective DNase activity during COVID-19.
Upon completion, participant should be able to identify DNase as potential treatment of excessive immunothrombosis and the importance of setting up clinical trials to evaluate its efficacy in IV administration.