# Role of Endothelial eNAMPT Secretion and TLR4 Signaling in the ARDS Vascular Endotype

> **NIH NIH R01** · UNIVERSITY OF ARIZONA · 2022 · $232,675

## Abstract

This A1 application is focused on the critical role of extracellular nicotinamide phosphoribosyltransferase
(eNAMPT) in driving lung vascular inflammation and multi-organ endothelial cell (EC) permeability, events that
are central to increasing ARDS mortality and the COVID-19-ARDS vascular endotype. We initially identified
eNAMPT as a novel ARDS and ventilator-induced lung injury (VILI) therapeutic target utilizing genomic–intensive
approaches and cellular and preclinical studies of excessive mechanical stress/VILI. We showed eNAMPT is a
novel ARDS biomarker with plasma eNAMPT levels increasing in response to viral/bacterial infection and expo-
sure to mechanical ventilation. Importantly, utilizing conditional EC–specific NAMPT KO mice, we have recently
shown that EC contributions to ARDS pathobiology includes eNAMPT secretion into the circulation thereby driv-
ing preclinical ARDS inflammatory lung injury and severity. We have shown that eNAMPT produces these inju-
rious effects by functioning as a damage-associated molecular pattern protein (DAMP) and master regulator of
evolutionarily-conserved inflammatory cascades via novel ligation of the Toll–like receptor 4 (TLR4). Our ex-
citing preclinical data in both rat and porcine ARDS/VILI models have validated the efficacy of the eNAMPT-
neutralizing humanized mAb (ALT-100) in reducing eNAMPT- and LPS-induced TLR4 activation and NFκB-
driven cytokine production, lung permeability and inflammatory lung injury. To further interrogate and validate
eNAMPT as a ARDS therapeutic target, Specific Aim #1 will extend prior studies which showed ROS-generating
ARDS stimuli (hypoxia, hyperoxia, mechanical stress, cytokines) to induce NAMPT expression and NAMPT pro-
moter SNPs to significantly increase eNAMPT plasma levels and risk of ARDS mortality (reduced ventilator-free
days, increased ARDS mortality). SA #1 will characterize the role of three key transcription factors (hypoxia-
inducible factors HIF1/2, NRF2), NAMPT and TLR4 promoter SNPs, and DNA methylation sites in genetic/ep-
igenetic regulation of NAMPT and TLR4 promoter activities. As eNAMPT secretion is key to initiation of inflam-
matory cascade activation, SA #2 will mechanistically explore novel regulation of TLR4- and mechanical stress-
stimulated eNAMPT secretion via extracellular vesicle formation, inflammasome activation, and ABC transport-
ers. As treatment with the eNAMPT-neutralizing ALT-100 mAb reversed the dramatic increases in Akt1 nitration,
MAP kinase effector activation, and reduced Akt/mTOR deubiquitination, SA #3 will dissect the structure/function
mechanisms involved in eNAMPT-TLR4 binding and stimulated increases in EC permeability with specific focus
on MAP kinase effector p90rsk, Akt1 nitration, and UCHL1 activity in EC cytoskeletal-driven barrier dysfunction.
Finally, SA #4 will optimize eNAMPT ALT-100 mAb dosing and time of delivery as a therapeutic strategy in
preclinical rat and porcine ARDS/VILI models. The dissection o...

## Key facts

- **NIH application ID:** 10440855
- **Project number:** 1R01HL158631-01A1
- **Recipient organization:** UNIVERSITY OF ARIZONA
- **Principal Investigator:** Joe G. N. Garcia
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $232,675
- **Award type:** 1
- **Project period:** 2022-05-20 → 2022-08-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10440855

## Citation

> US National Institutes of Health, RePORTER application 10440855, Role of Endothelial eNAMPT Secretion and TLR4 Signaling in the ARDS Vascular Endotype (1R01HL158631-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10440855. Licensed CC0.

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