# Antidote for inhaled CO poisoning based on mutationally engineered neuroglobin

> **NIH NIH R01** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2020 · $708,733

## Abstract

Project Summary/Abstract
 Carbon monoxide (CO) poisoning remains a major cause of death and disability, affecting 50,000
people per year in the United States alone. Patients removed from fires or following exposure to car and home
generator exhaust are placed on 100% oxygen and transferred to a facility with a hyperbaric oxygen delivery
system. Despite the availability of hyberbaric therapy centers in most major cities, inherent delays in access to
and initiation of therapy greatly limit efficacy. In fact, even with hyberbaric oxygen therapy, 1-2% of patients die
and >25% of surviving patients exhibit neurocognitive impairments. There is currently no point-of-care antidote
for CO poisoning available clinically.
 In the present proposal, we continue our studies developing novel antidotal therapies for CO poisoning,
based on our findings that extremely high affinity heme-based molecules can bind and sequester CO from red
blood cells and tissue mitochondria to reverse the systemic ischemia of CO poisoning. In the previous funding
period, we discovered a surprising and near-irreversible CO-binding affinity of mutationally engineered human
neuroglobin (Ngb). Ngb is a six-coordinate hemoprotein, with the heme iron coordinated by two histidine
residues. We mutated the distal histidine to glutamine (H64Q) and three surface-thiols to form a five-coordinate
heme protein (Ngb-H64Q-CCC) that has very high solubility (>10mM), allowing for high concentration and
intravenous infusion. This molecule binds CO ~ 500 times more strongly than hemoglobin. Infusions of Ngb-
H64Q-CCC in CO-poisoned mice enhanced CO removal from red blood cells in vivo from 25 minutes to 25
seconds, restored heart rate and blood pressure, increased survival from less than 10% to over 85%, and were
followed by rapid renal elimination of CO-bound Ngb-H64Q-CCC.
 These findings provide proof-of-concept that heme-based scavenger molecules with very high CO
binding affinity can be developed as potential antidotes for CO poisoning. We aim to continue development of
our Ngb-H64Q-CCC molecule, evaluating efficacy on the restoration of cellular aerobic respiration, safety, and
acute- and long-term effects on cardiovascular and cognitive function and survival in pre-clinical models, and
scaling production of recombinant protein for clinical development. We also aim to further discover novel CO
scavenger small molecules, based on knowledge derived from our previous studies. We will mutationally
engineer heme-bound, small 6-12 amino acid peptides derived from microperoxidase, with and without iron-to-
cobalt metal substitutions to limit redox reactivity and enhance CO affinity.
 Overall, these proposed studies are in keeping with the mission of the NHLBI and NIH to advance
highly impactful, significant, and novel studies that have great potential to improve the public health. Support
for these proposed studies has the potential to change our current paradigm for therapy of CO poisoning.

## Key facts

- **NIH application ID:** 9844481
- **Project number:** 5R01HL125886-06
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** Mark T Gladwin
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $708,733
- **Award type:** 5
- **Project period:** 2014-12-01 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9844481

## Citation

> US National Institutes of Health, RePORTER application 9844481, Antidote for inhaled CO poisoning based on mutationally engineered neuroglobin (5R01HL125886-06). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9844481. Licensed CC0.

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