PhD Scientific Days 2020

Molecular Sciences II. Lectures

Oxidized Hemoglobin Forms Contribute to NLRP3 Inflammasome-Driven IL- 1β Production upon Intravascular Hemolysis

Előadó neve

Nyakundi, Benard, MSc

Előadó munkahelye

University of Debrecen

Előadó telefonszáma

+36303012676

Előadó e-mail címe

bogonko.nyakundi@med.unideb.hu

Az előadás címe

Oxidized Hemoglobin Forms Contribute to NLRP3 Inflammasome-Driven IL- 1β Production upon Intravascular Hemolysis

Szerző(k) neve és munkahelye

Benard Nyakundi1,2, Andrea Toth1,2, Eniko Balogh, Judit Erdei1,2, Viktoria Jeney1
1 MTA- DE Lendulet Vascular Pathophysiology Research Group, Research Centre for Molecular Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
2 Doctoral School of Molecular Cell and Immune Biology, Faculty of Medicine University of Debrecen, Debrecen Hungary

Szekció

Molecular Sciences II. Lectures

Language of the presentation

English

Section, first choice

Molecular Sciences

Section, second choice

Theoretical and Translational Medicine

Összefoglaló szövege

Introduction: Damage associated molecular patterns (DAMPs) are released from red blood cells (RBCs) during intravascular hemolysis (IVH). Extracellular heme, with its pro-oxidant, pro-inflammatory and cytotoxic effects, is sensed by innate immune cells through pattern recognition receptors such as toll-like receptor 4 and nucleotide-binding domain and leucine-rich repeat-containing family, pyrin domain containing 3 (NLRP3), while the availability of free heme is strictly controlled.
Aims: To establish the formation of oxidized Hb forms in vivo upon sterile intravascular hemolysis and to investigate the involvement of different Hb forms in the hemolysis-associated inflammatory response.
Methods: We used C57BL/6 (WT) and NLRP3-/- mice and induced IVH by injecting phenylhydrazine into the peritoneal cavity of mice. The levels of Hb redox forms were determined spectrophotometrically in plasma, heme was determined by a heme assay kit, IL-1β was measured by ELISA. Expressions (mRNA and protein) of NLRP3, caspase-1, and IL-1β were determined by quantitative RT-PCR and western blot. Peritoneal infiltration of monocytes and neutrophils was assessed by flow cytometry. In vitro study was performed on murine macrophages.
Results: We found that after IVH most of the extracellular heme molecules are localized in oxidized Hb forms. IVH was associated with caspase-1 activation and formation of mature IL-1β in plasma and in the liver of C57BL/6 mice. We showed that ferrylHb (FHb) induces active IL-1β production in LPS-primed macrophages in vitro and triggered intraperitoneal recruitment of neutrophils and monocytes, caspase-1 activation and active IL-1β formation in the liver of C57BL/6 mice. NLRP3 deficiency provided a survival advantage upon IVH, without influencing the extent of RBC lysis or the accumulation of oxidized Hb forms. However, both hemolysis-induced and FHb-induced pro-inflammatory responses were largely attenuated in Nlrp3-/- mice.
Conclusion: We concluded that besides heme, FHb is a potent trigger of NLRP3 activation and production of IL-1β in vitro and in vivo, suggesting that FHb may contribute to hemolysis-induced inflammation. Identification of RBC-derived DAMPs might allow us to develop new therapeutic approaches for hemolytic diseases.

Additional Information

Supervisor :Viktoria Jeney
E-mail address: jeneyv@belklinika.com

EFOP-3.6.3-VEKOP-16-2017-00009

Bemutatás módja

Szóbeli

Kind

Szabad

Status

elfogadva

Accepted presentation method

szóbeli

Előadás fájl jóváhagyás

nem rendelkezett róla

Előadó

4702

Start

12:05

End

12:20

Authors (legacy)

Benard Nyakundi1,2, Andrea Toth1,2, Eniko Balogh, Judit Erdei1,2, Viktoria Jeney1
1 MTA- DE Lendulet Vascular Pathophysiology Research Group, Research Centre for Molecular Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
2 Doctoral School of Molecular Cell and Immune Biology, Faculty of Medicine University of Debrecen, Debrecen Hungary