Abstract
Acute inflammatory diseases are the leading causes of mortality in intensive care units. Myeloid differentiation 2 (MD‐2) is required for recognizing lipopolysaccharide (LPS) by toll‐like receptor 4 (TLR4), and represents an attractive therapeutic target for LPS‐induced inflammatory diseases. In this study, we report a chalcone derivative, L2H21, as a new MD2 inhibitor, which could inhibit LPS‐induced inflammation both in vitro and in vivo. We identify that L2H21 as a direct inhibitor of MD‐2 by binding to Arg90 and Tyr102 residues in MD‐2 hydrophobic pocket using a series of biochemical experiments, including surface plasmon response, molecular docking and amino acid mutation. L2H21 dose dependently inhibited LPS‐induced inflammatory cytokine expression in primary macrophages. In mice with LPS intratracheal instillation, L2H21 significantly decreased LPS‐induced pulmonary oedema, pathological changes in lung tissue, protein concentration increase in bronchoalveolar lavage fluid, inflammatory cells infiltration and inflammatory gene expression, accompanied with the decrease in pulmonary TLR4/MD‐2 complex. Meanwhile, administration with L2H21 protects mice from LPS‐induced mortality at a degree of 100%. Taken together, this study identifies a new MD2 inhibitor L2H21 as a promising candidate for the treatment of acute lung injury (ALI) and sepsis, and validates that inhibition of MD‐2 is a potential therapeutic strategy for ALI.
Highlights
Acute lung injury (ALI) and the acute respiratory distress syndrome are major causes of respiratory failure in critically ill patients [1]
We firstly determined the direct interaction between L2H21 and Recombinant human MD-2 (rhMD-2) protein with surface plasmon resonance (SPR) analysis and fluorescence spectroscopy
The SPR experiments indicate that L2H21 directly binds Myeloid differentiation 2 (MD-2) protein in a dose-dependent manner and with a very high affinity (KD value = 19.1 lM) (Fig. 1B), higher than that of L6H21, a previously reported MD-2 inhibitor sharing the chalcone structure (KD value = 33.3 lM) [24]
Summary
Acute lung injury (ALI) and the acute respiratory distress syndrome are major causes of respiratory failure in critically ill patients [1]. An acute inflammatory disease is the most common cause of ALI. Sepsis is the 10th leading cause of death overall and accounts for major healthcare expenditures in the developing world [2]. Profound understanding of ALI pathogenesis and recent advances in supportive treatments, mortality rate from ALI remains high at approximately 40% [3]. Effective pharmacotherapy for ALI and sepsis is extremely limited.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
