Develop novel iNOS/NO inhibitors for mitigating inflammatory cell death, ARDS, and MODS - Project Summary Many causes can trigger excessive production of inflammatory cytokines (i.e., cytokine storm). Elevated circulating cytokines induce extensive cell death (i.e., inflammatory cell death) that causes severe organ injuries, eventually leading to acute respiratory distress syndrome (ARDS) and multi-organ dysfunction (MODS). Patients with ARDS and MODS have extremely high mortality (~46%). There is an unmet clinical need for novel therapeutics capable of inhibiting inflammatory cell death to mitigate ARDS and MODS. Recent studies find that the excessive expression of inducible Nitric Oxide Synthase (iNOS) and over-production of nitric oxide (NO) play a critical role in inflammatory cell death. Therefore, inhibiting iNOS/NO represents a promising therapeutic approach. Hydrogen sulfide (H2S), a gaseous signaling molecule in our body, is known for its capability to inhibit iNOS and quench NO. However, due to its gaseous nature, its therapeutic application is limited by the challenge of administering a precise dose into the target cells sustainably. Preliminary studies developed five polymeric micelles containing H2S donating-anethole dithiolethione (ADT) groups to overcome the problem. The micelles enter cells via endocytosis and release H2S upon oxidation by reactive oxygens species (ROS) inside cells. The release rate can be controlled by changing the polymer design. The micelles have no significant cytotoxicity. In a proof-of-concept study, the micelles effectively inhibited cytokine-induced cell death. In short, the data show that the micelles are promising drug candidates. This project proposes systematically evaluating their therapeutic potential using vitro and mouse models, with the goal of gathering robust evidence to support their advancement into full drug development. The hypothesis is that the micelles can effectively mitigate iNOS/NO, inflammatory cell death, ARDS, and MODS. Aim 1 will test the hypothesis that micelles can mitigate iNOS/NO activity and inflammatory cell death in vitro. Aim 2 will test the hypothesis that micelles can mitigate cytokine storm, inflammatory cell death, organ injury, and mortality in mouse models. This project will collect essential efficacy/potency data, identify the most promising candidates, and provide valuable insights into polymer structure-property relationships to optimize these candidates further. The work is significant, as it has the potential to lead to novel therapeutics for managing ARDS and MODS, conditions responsible for ~11 million deaths annually. In terms of innovation, this is the first to investigate H₂S as an iNOS/NO inhibitor to reduce inflammatory cell death, cytokine storms, ARDS, and MODS. The micelle design is also highly innovative, enabling sustained, targeted, and ROS-responsive intracellular delivery of H₂S - a combination of features currently unmatched by any existing technology.
