Description
Small molecules that promote osteoblast differentiation might be useful as therapeutic agents for bone diseases such as osteoporosis. Purmorphamine is a 2,6,9-
trisubstituted purine that promotes the differentiation of both human and mouse mesenchymal progenitor cells into osteoblasts.
1,2 The EC
50 value for differentiation of C3H10T1/2 cells based on alkaline phosphatase expression is 1 μM.
1 Investigation into purmorphamine’s mechanism of action indicates that it directly binds to and activates the 7-
transmembrane Smo receptor of the Hedgehog signaling pathway.
3,4
Chemical Properties
Light Tan Solid
Uses
Activates the Hedgehog pathway by targeting Smoothened
Uses
An activator of the hedgehog (Hh) signaling pathway.
Definition
ChEBI: A member of the class of purines that is purine substituted at C-2 by a 1-naphthyloxy group, at C-4 by a 4-morpholinophenylamino group, and at N-9 by a cyclohexyl group.
Biological Activity
Cell permeable purine compound. Induces osteoblast differentiation. Agonist of smoothened by activation of the Hedgehog (Hh) pathway. Also shown to induce transdifferentiation in pre-adipocytes and myoblasts. Binds to and activates 7-transmembrane receptor of Hh.
Biochem/physiol Actions
Purmorphamine activates the Hedgehog (Hh) signaling pathway, directly binding to the Smoothened (Smo) receptor. In various studies, purmorphamine has been shown to induce osteoblast differentiation, generate cardiomyocytes from human embryonic stem cells, increase the neuronal differentiation of a human striatal neural stem cell line, and to differentiate human umbilical cord mesenchymal stem cells (hUCMSCs) into motoneurons.
in vitro
purmorphamine activated the hedgehog pathway by directly bound and activated smoothened with the ic50value of ~ 1.5 μm in competing with cyclopamine, a smo antagonist [1]. in multi-potent c3h10t1/2 cells, purmorphamine was a potent inducer of osteogenesis. in c3h10t1/2 cells, the ec50 values assessed based on alp expression for purmorphamine was 1 μm. purmorphamine (1 μm) in combination with bmp-4 (100 ng/ml) increased alp activity more than 90-fold in 3t3-l1 cells [3].administration of purmorphamine at 3 and 5 μm up-regulated the level of osteocalcin on day 14 (p ≤ 0.05)[4].
Enzyme inhibitor
This Smo activator (FW = 520.62 g/mol; CAS 483367-10-8; Solubility: 4
mg/mL DMSO; <1 mg/mL H2O), also named 9-cyclohexyl-N-[4- (4-
morpholinyl) phenyl]-2- (1-naphthalenyloxy) -9H-purin-6-amine, targets
Smoothened and blocks BODIPY-cyclopamine binding (IC50 ~ 1.5 μM).
Purmorphamine is also an inducer of osteoblast differentiation (EC50 = 1
μM).
in vivo
in rats transplanted with stem cell-based constructs subcutaneously, treatment with purmorphamine tended to up-regulate alp transcripts when compared with those injected by either dexamethasone or injection water (p ≤ 0.05) [4].
References
1) Wu et al. (2002), A small molecule with osteogenesis-inducing activity in multipotent mesenchymal progenitor cells; J. Am. Chem. Soc., 124 14520
2) Wu et al. (2004), Purmorphamine induces osteogenesis by activation of the hedgehog signaling pathway; Chem. Biol. 11 1229
3) Sinha and Chen (2006), Purmorphamine activates the Hedgehog pathway by targeting Smoothened; Nat. Chem. Biol., 2 29
4) Kang et al. (2015), Reprogramming of mouse somatic cells into pluripotent stem-like cells using a combination of small molecules; Biomaterials, 35 7336
5) Zhang et al. (2015), Small Molecules Efficiently Reprogram Human Astroglial Cells into Functional Neurons; Cell Stem Cell 17 735
