# Role of Endothelial eNAMPT/NAMPT secretion and TLR4 signaling in the ARDS Vascular Endotype

> **NIH NIH P01** · UNIVERSITY OF ARIZONA · 2022 · $97,951

## Abstract

ABSTRACT:
The global COVID-19 pandemic has dramatically highlighted the critical role of lung vascular inflammation and
multi-organ endothelial cell (EC) permeability in ARDS mortality and the unprecedented COVID-19-ARDS vas-
cular endotype (1). This A1 Project #2 application remains focused on the critical role of eNAMPT (extracellular
nicotinamide phosphoribosyltransferase) in driving lung vascular inflammation and multi-organ endothelial
cell (EC) permeability, events that are central to increasing ARDS mortality. 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 exposure to me-
chanical ventilation. Importantly, utilizing conditional EC–specific Nampt KO mice, we have recently shown that
EC contributions to ARDS pathobiology via eNAMPT secretion into the circulation, thereby driving pre-
clinical ARDS inflammatory lung injury and severity. eNAMPT produces these injurious effects by functioning as
a damage-associated molecular pattern protein (DAMP) and master regulator of evolutionarily-conserved inflam-
matory cascades via novel ligation of the Toll–like receptor 4 (TLR4). Our exciting data in mouse, rat and porcine
ARDS/VILI models have validated the efficacy of the eNAMPT-neutralizing humanized mAb (ALT-100) in re-
ducing eNAMPT- and LPS-induced TLR4 activation, NFκB-driven cytokine production, lung permeability and
inflammatory lung injury. To further interrogate eNAMPT as an ARDS therapeutic target, SA #1 will extend prior
studies which showed ROS-generating ARDS stimuli (hypoxia, hyperoxia, mechanical stress, cytokines) to in-
duce NAMPT expression and characterize the role of three key transcription factors (hypoxia-inducible factors
HIF1a/2a, NRF2), NAMPT/TLR4 promoter SNPs, and DNA methylation in genetic/epigenetic regulation of
NAMPT/TLR4 promoter activities. SA #2 will mechanistically explore novel regulation of TLR4- and mechanical
stress-stimulated eNAMPT secretion, a key event to initiation of inflammatory cascade activation, via extracellu-
lar vesicle formation, inflammasome activation, and ABC transporters. Utilizing Core B's CRISPR/Cas9- gener-
ated EC lines, SA #3 will dissect the structure/function mechanisms involved in eNAMPT-TLR4 binding and
increases in EC permeability with specific focus on MAP kinase effector p90rsk, Akt1 nitration, and UCHL1
activity in EC cytoskeletal-driven barrier dysfunction. Finally, utilizing Core C expertise, SA #4 will optimize eN-
AMPT ALT-100 mAb dosing, define the therapeutic window for ALT-100 delivery, and define potential ALT-100
mAb synergy with other PPG therapeutic modalities utilizing preclinical rat and porcine ARDS/VILI models. This
high integration of Project #2 with each PPG Project will...

## Key facts

- **NIH application ID:** 10496461
- **Project number:** 2P01HL126609-06A1
- **Recipient organization:** UNIVERSITY OF ARIZONA
- **Principal Investigator:** Joe G. N. Garcia
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $97,951
- **Award type:** 2
- **Project period:** 2016-09-20 → 2023-01-05

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10496461

## Citation

> US National Institutes of Health, RePORTER application 10496461, Role of Endothelial eNAMPT/NAMPT secretion and TLR4 signaling in the ARDS Vascular Endotype (2P01HL126609-06A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10496461. Licensed CC0.

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