Tryptophan hydroxylase 1 (Tph-1)-targeted bone anabolic agents for osteoporosis

J Med Chem. 2014 Jun 12;57(11):4692-709. doi: 10.1021/jm5002293. Epub 2014 May 29.

Abstract

Tryptophan hydroxylase 1 (Tph-1), the principal enzyme for peripheral serotonin biosynthesis, provides a novel target to design anabolic agents for osteoporosis. Here, we present a design, synthesis of a novel series of ursolic acid derivatives under the guidance of docking technique, and bioevaluation of the derivatives using RBL2H3 cells and ovariectomized (OVX) rats. Of the compounds, 9a showed a potent inhibitory activity on serotonin biosynthesis. Further investigations revealed that 9a, as an efficient Tph-1 binder identified by SPR (estimated KD: 6.82 μM), suppressed the protein and mRNA expressions of Tph-1 and lowered serotonin contents in serum and gut without influence on brain serotonin. Moreover, oral administration of 9a elevated serum level of N-terminal propeptide of procollagen type 1 (P1NP), a bone formation marker, and improved bone microarchitecture without estrogenic side effects in ovariectomized rats. Collectively, 9a may serve as a new candidate for bone anabolic drug discovery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anabolic Agents / chemical synthesis*
  • Anabolic Agents / chemistry
  • Anabolic Agents / pharmacology
  • Animals
  • Bone and Bones / drug effects*
  • Bone and Bones / metabolism
  • Brain / drug effects
  • Brain / metabolism
  • Cell Line
  • Female
  • Gastrointestinal Tract / drug effects
  • Gastrointestinal Tract / metabolism
  • Humans
  • Molecular Docking Simulation
  • Osteoporosis / drug therapy*
  • Osteoporosis / metabolism
  • Ovariectomy
  • Protein Binding
  • Quinoxalines / chemical synthesis
  • Quinoxalines / chemistry
  • Quinoxalines / pharmacology
  • RNA, Messenger / metabolism
  • Rats
  • Serotonin / biosynthesis
  • Structure-Activity Relationship
  • Surface Plasmon Resonance
  • Triterpenes / chemical synthesis*
  • Triterpenes / chemistry
  • Triterpenes / pharmacology
  • Tryptophan Hydroxylase / genetics
  • Tryptophan Hydroxylase / metabolism*
  • Ursolic Acid

Substances

  • Anabolic Agents
  • Quinoxalines
  • RNA, Messenger
  • Triterpenes
  • Serotonin
  • TPH1 protein, human
  • TPH2 protein, human
  • Tryptophan Hydroxylase