Lipid A-based affinity biosensor for screening anti-sepsis components from herbs.

Area of Science:

• Biotechnology
• Pharmacology
• Traditional Chinese Medicine

Background:

• Sepsis pathogenesis involves lipopolysaccharide (LPS) from Gram-negative bacteria, with lipid A being crucial for toxicity.
• Neutralizing LPS is a potential strategy for sepsis prevention.
• Traditional Chinese medicines (TCMs) show promise as natural LPS antagonists.

Purpose of the Study:

• To develop a rapid, lipid A-based affinity biosensor for screening anti-sepsis components from TCMs.
• To identify and isolate active compounds from selected TCMs with high lipid A binding affinity.
• To evaluate the in vitro and in vivo efficacy of the isolated compounds against sepsis.

Main Methods:

• A resonant mirror-based affinity biosensor was constructed by immobilizing n-octyl β-D-glucopyranoside (OG) to bind lipid A.
• 78 TCMs were screened using the biosensor for lipid A binding.
• Positive extracts underwent further analysis using polyamide chromatography and IEC-HPLC to isolate active components.
• Biological activity was assessed by measuring TNFα release in LPS-induced RAW264.7 cells and survival rates in LPS- or E. coli-challenged mice.

Main Results:

• The affinity biosensor successfully screened 78 herbs, identifying Paeonia suffruticosa Andr (PSA) extract as having the highest lipid A binding capability.
• A specific component, PSA-I-3, was isolated from PSA and confirmed to bind lipid A via the biosensor.
• PSA-I-3 demonstrated dose-dependent inhibition of TNFα release in vitro.
• PSA-I-3 significantly enhanced the survival rate of mice challenged with lethal doses of LPS or heat-killed E. coli.

Conclusions:

• The developed lipid A-based affinity biosensor is an effective tool for rapidly screening anti-sepsis compounds from TCMs.
• Paeonia suffruticosa Andr contains a component (PSA-I-3) with significant anti-sepsis activity, demonstrated by its ability to reduce inflammation and increase survival.
• This study validates the potential of TCMs as a source for novel sepsis therapeutics and highlights the utility of biosensor technology in drug discovery.