Engineering a highly selective, hemoprotein-based scavenger as a carbon monoxide poisoning antidote with no hypertensive effect

Dent, M. R.; DeMartino, A. W.; Xu, Q.; Chen, X.; Ghandi, A.; Hwang, J.; Bocian, K. A.; Alipour, E.; Ucer, B.; Baker, S. R.; Srimath Kandada, A. R.; Bulbul, A.; Kim-Shapiro, D. B.; Rose, J. J.; Tejero, J.; Gladwin, M. T.

doi:10.1101/2025.01.18.633417

bioRxiv · 10.1101/2025.01.18.633417

Engineering a highly selective, hemoprotein-based scavenger as a carbon monoxide poisoning antidote with no hypertensive effect

Dent, M. R.·DeMartino, A. W.·Xu, Q.·Chen, X.·Ghandi, A.·Hwang, J.·Bocian, K. A.·Alipour, E.·Ucer, B.·Baker, S. R.·Srimath Kandada, A. R.·Bulbul, A.·Kim-Shapiro, D. B.·Rose, J. J.·Tejero, J.·Gladwin, M. T.

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Abstract

Carbon monoxide (CO) poisoning causes 50,000-100,000 emergency department visits and [~]1,500 deaths in the United States annually. Current treatments are limited to supplemental and/or hyperbaric oxygen to accelerate CO elimination. Even with oxygen therapy, nearly half of CO poisoning survivors suffer long-term cardiac and neurocognitive deficits related to slow CO clearance, highlighting a need for point of care antidotal therapies. Given the natural interaction between CO and ferrous heme, we hypothesized that the hemoprotein RcoM, a transcriptional regulator of microbial CO metabolism, would make an ideal platform for CO-selective scavenging from endogenous hemoproteins. We engineered an RcoM truncate (RcoM-HBD-CCC) that exhibits high CO affinity (Ka,CO = 2.8x1010 M-1), remarkable selectivity for CO over oxygen (Ka,O2 = 1.4x105 M-1; Ka,CO/Ka,O2 = 1.9x105), thermal stability (Tm = 72{degrees}C), slow autoxidation rate (kox = 1.1 h-1). In a murine model of acute CO poisoning, infused RcoM-HBD-CCC accelerated CO clearance from hemoglobin in red blood cells and was rapidly excreted in urine. Moreover, infused RcoM-HBD-CCC elicited minimal hypertension in mice compared to infused hemoglobin, attributed to a comparatively limited reactivity toward nitric oxide (NO) via dioxygenation (kNOD(RcoM) = 6-8x106 M-1s-1 vs kNOD(Hb) = 6-8x107 M-1s-1). These data suggest that RcoM-HBD-CCC is a safe, selective, and efficacious CO scavenger. Additionally, by limiting hypertension RcoM-HBD-CCC improves end-organ adverse effects compared with hemoglobin-based therapeutics.

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Dent, M. R., DeMartino, A. W., Xu, Q., Chen, X., Ghandi, A., Hwang, J., Bocian, K. A., Alipour, E., Ucer, B., Baker, S. R., Srimath Kandada, A. R., Bulbul, A., Kim-Shapiro, D. B., Rose, J. J., Tejero, J., Gladwin, M. T.. 2025-01-19. Engineering a highly selective, hemoprotein-based scavenger as a carbon monoxide poisoning antidote with no hypertensive effect. https://doi.org/10.1101/2025.01.18.633417

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