Thursday, July 3, 2025 7/3/2025

Renewal: Pannexin-1 signaling in abdominal aortic aneurysms

Award Number: R01HL138931
ORGANIZATION: NATIONAL HEART, LUNG, & BLOOD INSTITUTE
OPDIV: NIH
AWARD CLASS: DISCRETIONARY
AWARD ACTIVITY TYPE: SCIENTIFIC/HEALTH RESEARCH (INCLUDES SURVEYS)
PERIOD OF PERFORMANCE START DATE: 07/09/2018
PERIOD OF PERFORMANCE END DATE: 06/30/2028

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Renewal: Pannexin-1 signaling in abdominal aortic aneurysms - PROJECT SUMMARY Abdominal aortic aneurysms (AAA) formation and subsequent aortic rupture can lead to sudden death and is a significant clinical problem with no currently known medical treatments available. The hallmarks of patient AAA include thrombus formation and cell death mechanisms such as apoptosis and neutrophil extracellular traps (NETs). The clearance of dead cell debris is mediated via the process of efferocytosis, by which apoptotic tissue is recognized for engulfment by professional phagocytes (e.g., macrophages) and non-professional phagocytes (e.g., endothelial cells; ECs), and remains to be elucidated in the pathogenesis of AAA. Thus, our hypothesis focuses on the dysregulation of inflammation-resolution pathways that lead to to defective efferocytosis and promote chronic aortic tissue inflammation and vascular remodeling. Our recent study has demonstrated a critical role orchestrated by EC-dependent pannexin-1 (Panx1) channels in causing aortic inflammation and AAA formation. The scientific premise of this proposal focuses on the dysregulation of EC- mediated efferocytosis causing an imbalance of inflammation-resolution via Panx1 activation in AAA progression. Therefore, the central hypothesis in this proposal is that EC efferocytosis is dysregulated due to cleavage of MerTK, a cell surface tyrosine kinase receptor that recognizes apoptotic cells, leading to accumulation of dead cell debris and thrombus formation. Second, our mechanistic studies will dissect the dynamic communication between ECs and macrophages, involving defective EC-mediated efferocytosis leading to excessive iron-mediated cell death (ferroptosis) in macrophages, that collectively feedbacks to cause Panx1 activation and an chronic inflammatory loop. Our supportive data demonstrates that resolution of aortic inflammation is associated with increased EC-dependent MerTK expression and efferocytosis of neutrophils. Furthermore, defective EC-mediated efferocytosis exacerbates ferroptosis in macrophages (via SLC7A11 and Nrf2-signaling) that feedbacks to cause EC-Panx1 activation and eATP release. Collectively, our results suggest that dysregulation of EC-mediated efferocytosis and macrophage-dependent ferroptosis creates a break in the inflammation-resolution process during AAA formation and aortic rupture. We will delineate the proposed studies using the murine elastase-treatment AAA and our innovative aortic rupture model, as well as by analysis of human AAA tissue from our biorepository. Using novel inducible cell-specific genetic knockout mice such as Cdh5Cre-ERT2/MerTKfl/fl, MerTKCR (cleavage-resistant), and Cx3CR1Cre- ERT2/SLC7A11fl/fl mice, we will delineate the previously unknown mechanisms of dysregulated efferocytosis and ferroptosis in activation of Panx1 channels during AAA formation. Our studies will provide novel insight into mechanisms of molecular signaling interactions between ECs and macrophages to define the inflammatory loop between efferocytosis/ferroptosis/Panx1 for the treatment of AAAs and prevention of aortic rupture.


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 = $709,060 )
2025	2025	UNIVERSITY OF FLORIDA	1523 UNION RD RM 207	GAINESVILLE	FL	32611	ALACHUA	USA	Cardiovascular Diseases Research	002	7	6/16/2025	NON-COMPETING CONTINUATION	$709,060
2025	2023	UNIVERSITY OF FLORIDA	1523 UNION RD RM 207	GAINESVILLE	FL	32611	ALACHUA	USA	Cardiovascular Diseases Research	001	5	2/19/2025	COMPETING CONTINUATION	$64
2025	2021	UNIVERSITY OF FLORIDA	1523 UNION RD RM 207	GAINESVILLE	FL	32611	ALACHUA	USA	Cardiovascular Diseases Research	000	4	2/19/2025	NON-COMPETING CONTINUATION	-$64
														Subtotal = $709,060

Issue Date FY: 2024 ( Subtotal = $694,879 )
2024	2024	UNIVERSITY OF FLORIDA	1523 UNION RD RM 207	GAINESVILLE	FL	32611	ALACHUA	USA	Cardiovascular Diseases Research	000	6	6/6/2024	NON-COMPETING CONTINUATION	$694,879
														Subtotal = $694,879

Issue Date FY: 2023 ( Subtotal = $722,185 )
2023	2023	UNIVERSITY OF FLORIDA	1523 UNION RD RM 207	GAINESVILLE	FL	32611	ALACHUA	USA	Cardiovascular Diseases Research	000	5	5/11/2023	COMPETING CONTINUATION	$722,185
														Subtotal = $722,185

Issue Date FY: 2021 ( Subtotal = $583,863 )
2021	2021	UNIVERSITY OF FLORIDA	1523 UNION RD RM 207	GAINESVILLE	FL	32611	ALACHUA	USA	Cardiovascular Diseases Research	000	4	6/16/2021	NON-COMPETING CONTINUATION	$583,863
														Subtotal = $583,863

Issue Date FY: 2020 ( Subtotal = $583,863 )
2020	2020	UNIVERSITY OF FLORIDA	1523 UNION RD RM 207	GAINESVILLE	FL	32611	ALACHUA	USA	Cardiovascular Diseases Research	000	3	6/27/2020	NON-COMPETING CONTINUATION	$583,863
														Subtotal = $583,863

Issue Date FY: 2019 ( Subtotal = $573,177 )
2019	2019	UNIVERSITY OF FLORIDA	1523 UNION RD RM 207	GAINESVILLE	FL	32611	ALACHUA	USA	Cardiovascular Diseases Research	000	2	7/5/2019	NON-COMPETING CONTINUATION	$573,177
														Subtotal = $573,177

Issue Date FY: 2018 ( Subtotal = $635,353 )
2018	2018	UNIVERSITY OF FLORIDA	1523 UNION RD RM 207	GAINESVILLE	FL	32611	ALACHUA	USA	Cardiovascular Diseases Research	000	1	7/9/2018	NEW	$635,353
														Subtotal = $635,353

Grand Total All Awards = $4,502,380

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Renewal: Pannexin-1 signaling in abdominal aortic aneurysms

Award Number: R01HL138931

ORGANIZATION: NATIONAL HEART, LUNG, & BLOOD INSTITUTE

OPDIV: NIH

AWARD CLASS: DISCRETIONARY

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

PERIOD OF PERFORMANCE START DATE: 07/09/2018

PERIOD OF PERFORMANCE END DATE: 06/30/2028

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