Vats, Ravi
(2022)
Title Page
Circulating Neutrophil Extracellular Traps Promote Gasdermin-D Dependent Lung Injury in Sickle Cell Disease.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Sickle Cell Disease (SCD) is a monogenic disorder caused by the homozygosity of the beta-S (βs) allele of the β-globin gene, which results in generation of mutant hemoglobin (HbS). Intra-erythrocytic polymerization of mutant hemoglobin promotes hemolysis, which leads to the development of sterile inflammation and acute systemic painful vaso-occlusive episodes (VOE). VOE is the predominant pathophysiology responsible for emergency hospitalization of SCD patients and often serves as an antecedent to development of Acute Chest Syndrome (ACS), which is a type of acute lung injury (ALI) and one of primary cause of mortality among SCD patients. Although epidemiological findings in humans and in-vivo imaging in transgenic-humanized SCD mice suggest a potential role for lung vaso-occlusion in development of ACS, the cellular, molecular, and biophysical mechanisms that promote lung vaso-occlusion and injury in SCD remain incompletely understood.
Using quantitative fluorescence intravital microscopy of the intact lung, liver, and kidney in live SCD mice, confocal microscopy of freshly isolated organs, and Imaging Flow Cytometry of SCD mice or patient plasma, I show that intravenous (IV) administration of oxy-Hb or hemin promotes neutrophil-platelet aggregates-dependent lung vaso-occlusion in SCD mice. Importantly, IV administration of recombinant tandem-P-selectin−glycoprotein ligand−immunoglobulin (TSGL-Ig) significantly attenuated IV oxy-Hb induced lung vaso-occlusion in SCD mice. These findings highlighted the therapeutic potential of TSGL-Ig in preventing VOE and ACS in SCD.
Remarkably, I also discovered a previously unknown phenomenon of the shedding of neutrophil extracellular traps (NETs) from parent neutrophils in the liver and how it contributes to development of lung vaso-occlusion in SCD mice. NETs were shed primarily in the liver of SCD mice administered IV oxy-Hb, and then traveled to the lung as circulating NETs (cNETs) to promote P-selectin independent pulmonary vaso-occlusion. I found that inhibiting caspase-4 (humans)/caspase-11 (mouse)-dependent activation of pore forming protein gasdermin-D (GSDMD), prevented shedding of cNETs in the liver, their translocation to the lung and the development of lung vaso-occlusion in SCD mice. Taken together, these studies introduce a novel paradigm that translocation of DAMPs from liver to lung promotes lung injury in SCD, and identify a new GSDMD-mediated, P-selectin-independent mechanism of lung injury in SCD.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
16 January 2022 |
| Date Type: |
Publication |
| Defense Date: |
7 July 2021 |
| Approval Date: |
16 January 2022 |
| Submission Date: |
1 November 2021 |
| Access Restriction: |
2 year -- Restrict access to University of Pittsburgh for a period of 2 years. |
| Number of Pages: |
150 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Bioengineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Sickle Cell Disease |
| Date Deposited: |
16 Jan 2023 06:00 |
| Last Modified: |
16 Jan 2023 06:00 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/41900 |
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