Effect of Modifier Structure on the Activation of Leukotriene A4 Hydrolase Aminopeptidase Activity

J Med Chem. 2019 Dec 12;62(23):10605-10616. doi: 10.1021/acs.jmedchem.9b00663. Epub 2019 Nov 21.

Abstract

Activation of the leukotriene A4 hydrolase (LTA4H) aminopeptidase (AP) activity with 4-methoxydiphenylmethane (4MDM) promoted resolution of neutrophil infiltration in a murine cigarette smoke-induced model for emphysematous chronic obstructive pulmonary disease. Recently, 4-(4-benzylphenyl)thiazol-2-amine (ARM1) was published as a ligand for LTA4H with potential anti-inflammatory properties. To investigate the effect of modifier structure on enzyme kinetics of LTA4H, a series of analogues bearing structural features of ARM1 and 4MDM were synthesized using trifluoroborate Suzuki coupling reactions. Following, the 2.8 Å X-ray crystal structure of LTA4H complexed with 4-OMe-ARM1, a 4MDM-ARM1 hybrid molecule, was determined. Kinetic analysis showed that ARM1 and related analogues lowered affinity for the enzyme-substrate complex, resulting in a change of mechanism from hyperbolic mixed predominately catalytic activation (HMx(Sp < Ca)A) as observed for 4MDM to a predominately specific activation (HMx(Sp > Ca)A) mechanism. 4-OMe-ARM1 was then shown to dose responsively reduce LTB4 production in human neutrophils.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aminopeptidases / metabolism*
  • Anti-Inflammatory Agents / chemistry
  • Anti-Inflammatory Agents / pharmacology*
  • Cells, Cultured
  • Enzyme Activation / drug effects*
  • Epoxide Hydrolases / genetics
  • Epoxide Hydrolases / metabolism*
  • Gene Expression Regulation / drug effects
  • Humans
  • Inflammation Mediators / metabolism
  • Leukotriene B4 / genetics
  • Leukotriene B4 / metabolism
  • Molecular Structure
  • Neutrophils / drug effects
  • Neutrophils / metabolism

Substances

  • Anti-Inflammatory Agents
  • Inflammation Mediators
  • Leukotriene B4
  • Epoxide Hydrolases
  • Aminopeptidases
  • leukotriene A4 hydrolase