Supramolecular Detoxification Approach of Endotoxin Through Host–Guest Complexation by a Giant Macrocycle

TL;DR

A new method using a giant macrocycle to detoxify endotoxins from bacteria is shown to reduce inflammation and save lives in mice.

Contribution

A supramolecular detoxification strategy using CPP3 macrocycle is introduced, showing strong LPS binding and in vivo efficacy.

Findings

CPP3 binds to LPS with an association constant of (4.79 ± 0.29) × 10⁸ M⁻¹.

CPP3 reduces LPS-induced cytotoxicity by inhibiting ROS and cytokine production.

In vivo, CPP3 improved survival rates of LPS-poisoned mice from 0% to 100% within 3 days.

Abstract

In Gram-negative bacteria, lipopolysaccharides (LPSs, also known as endotoxin) can induce extensive immune responses that will enable victims to produce severe septic shock syndrome. Because of the high mortality of sepsis in the face of standard treatment, advance detoxification schemes are urgently needed in clinics. Herein, we described a supramolecular detoxification approach via direct host–guest complexation by a giant macrocycle. Cationic pentaphen[3]arene (CPP3) bearing multiple quaternary ammonium groups was screened as a candidate antidote. CPP3 exhibited robust binding affinity toward LPS with an association constant of (4.79 ± 0.29) × 108 M−1. Co-dosing with an equivalent amount of CPP3 has been demonstrated to decrease LPS-induced cytotoxicity on a cellular level through inhibiting ROS generation and proinflammatory cytokine expression. In vivo experiments have further proved that post-treatment by CPP3 could significantly improve the survival rate of LPS-poisoned mice from 0 to 100% over a period of 3 days, and inflammatory abnormalities and tissue damage were also alleviated.

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