Tuesday, September 16, 2025 9/16/2025

Low Density Neutrophils Link Inflammation and Coagulopathy in COVID-19

Award Number: R01HL158779
ORGANIZATION: NATIONAL HEART, LUNG, & BLOOD INSTITUTE
OPDIV: NIH
AWARD CLASS: DISCRETIONARY
AWARD ACTIVITY TYPE: SCIENTIFIC/HEALTH RESEARCH (INCLUDES SURVEYS)
PERIOD OF PERFORMANCE START DATE: 09/23/2022
PERIOD OF PERFORMANCE END DATE: 08/31/2026

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Low Density Neutrophils Link Inflammation and Coagulopathy in COVID-19 - Project Summary Coronavirus disease 2019 (COVID-19) is a potentially life threatening disease caused by the novel viral pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Approximately 20% of COVID-19 patients experience severe disease, typically presenting with bilateral pneumonia, and about 5% progress to acute respiratory distress syndrome (ARDS). ARDS results from a combination of virally induced lung injury and the rapid influx of immune cells that release inflammatory mediators leading to a hyper-activated state known as cytokine storm. COVID-19 ARDS is further exacerbated by a unique diffuse coagulopathy leading to thrombus formation in the venous and arterial circulations and microthrombi in capillaries of the lungs. Predisposing factors for this coagulopathy include increased fibrinogen, activated coagulation cascade, platelet activation, hyper- inflammation, neutrophil extracellular trap (NET) formation, and endothelial cell damage. Understanding the pathophysiology of COVID-19 coagulopathy and ARDS is critical to finding effective therapeutic interventions. Accumulating evidence indicates critical roles of neutrophils in both ARDS and immunothrombosis in COVID-19. Our preliminary studies identified a novel population of low-density neutrophils (LDN) which expresses intermediate levels of CD16 (CD16Int LDN) in COVID-19 patients. The number of CD16Int LDN correlated with disease severity, levels of inflammatory cytokines IL-6/TNF-a, D-dimer levels, and clinical outcomes. In addition, CD16Int LDN showed spontaneous NET formation and evidence of in vivo platelet activation and granule exocytosis. Based on these findings, we postulate that CD16Int LDN play a critical role in the induction of coagulopathy and pulmonary inflammation in severe and critical COVID-19 patients. Three specific Aims are proposed to further dissect the underlying mechanisms. Aim 1 will comprehensively characterize LDN subsets using proteomics and transcriptomics approaches. The information gained from those studies will be used to refine our CyTOF antibody panel. We will use this panel to track differential neutrophil clusters in longitudinal patient samples. Aim 2 will determine LDN subsets functional changes during disease progression and their contributions to dysregulated inflammatory response and coagulopathy in severe and critical COVID- 19 patients. Neutrophil degranulation, NET formation, phagocytosis, chemotaxis, apoptosis, and cytokine release will be examined. We will also determine if LDN promote coagulopathy in COVID-19 patients. Aim 3 will determine whether inhibition of neutrophil granule exocytosis using our novel TAT-fusion protein inhibitors prevents activated neutrophil-mediated functional changes and hypercoagulation. We will also use a hACE2 Tg mouse model to determine the in vivo efficacy of TAT-fusion proteins on lung inflammation and impaired function. Successful completion of this proposal will provide novel insights into COVID-19 pathophysiology by defining the role of a unique subset of neutrophils and by establishing neutrophil degranulation as a therapeutic target for inhibiting inflammatory lung injury and immunothrombosis in COVID-19.


Issue Date FY	Funding FY	Legal Entity Name	Legal Entity Address	Legal Entity City	Legal Entity State	Legal Entity Zip Code	Legal Entity COUNTY	Legal Entity COUNTRY	Assistance Listing	Award Code	Budget Year	Action Date	Action Type	Action Amount

Issue Date FY: 2025 ( Subtotal = $720,048 )
2025	2025	UNIVERSITY OF LOUISVILLE	2301 S 3RD ST	LOUISVILLE	KY	40208	JEFFERSON	USA	Blood Diseases and Resources Research	000	4	9/8/2025	NON-COMPETING CONTINUATION	$720,048
														Subtotal = $720,048

Issue Date FY: 2024 ( Subtotal = $705,648 )
2024	2024	UNIVERSITY OF LOUISVILLE	2301 S 3RD ST	LOUISVILLE	KY	40208	JEFFERSON	USA	Blood Diseases and Resources Research	001	3	9/12/2024	NON-COMPETING CONTINUATION	$705,648
2024	2023	UNIVERSITY OF LOUISVILLE	2301 S 3RD ST	LOUISVILLE	KY	40208	JEFFERSON	USA	Blood Diseases and Resources Research	000	2	9/11/2024	NON-COMPETING CONTINUATION	$0
														Subtotal = $705,648

Issue Date FY: 2023 ( Subtotal = $761,423 )
2023	2023	UNIVERSITY OF LOUISVILLE	2301 S 3RD ST	LOUISVILLE	KY	40208	JEFFERSON	USA	Blood Diseases and Resources Research	001	2	9/8/2023	NON-COMPETING CONTINUATION	$761,423
2023	2022	UNIVERSITY OF LOUISVILLE	2301 S 3RD ST	LOUISVILLE	KY	40208	JEFFERSON	USA	Blood Diseases and Resources Research	000	1	9/1/2023	NEW	$0
														Subtotal = $761,423

Issue Date FY: 2022 ( Subtotal = $761,423 )
2022	2022	UNIVERSITY OF LOUISVILLE	2301 S 3RD ST	LOUISVILLE	KY	40208	JEFFERSON	USA	Blood Diseases and Resources Research	000	1	9/22/2022	NEW	$761,423
														Subtotal = $761,423

Grand Total All Awards = $2,948,542

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Low Density Neutrophils Link Inflammation and Coagulopathy in COVID-19

Award Number: R01HL158779

ORGANIZATION: NATIONAL HEART, LUNG, & BLOOD INSTITUTE

OPDIV: NIH

AWARD CLASS: DISCRETIONARY

AWARD ACTIVITY TYPE: SCIENTIFIC/HEALTH RESEARCH (INCLUDES SURVEYS)

PERIOD OF PERFORMANCE START DATE: 09/23/2022

PERIOD OF PERFORMANCE END DATE: 08/31/2026

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