Targeting soluble epoxide hydrolase promotes osteogenic–angiogenic coupling via activating SLIT3/HIF‐1α signalling pathway

Abstract

Type H vessels have recently been identified to modulate osteogenesis. Epoxyeicostrioleic acids (EETs) have an essential contribution to vascular homeostasis. However, whether increased EETs with soluble epoxide hydrolase (sEH) inhibitor TPPU enhance the coupling of angiogenesis and osteogenesis remains largely unknown. The effects of TPPU on cross‐talk between co‐cultured human umbilical vein endothelial cells (HUVECs) and human dental pulp stem cells (hDPSCs), and on long bone growth and calvarial defect repair in mice were investigated in vitro and in vivo. TPPU enhanced osteogenic differentiation of co‐cultured HUVECs and hDPSCs in vitro and increased type H vessels, and long bone growth and bone repair of calvarial defect. Mechanistically, TPPU promoted cell proliferation and angiogenesis, reclined cell apoptosis, and significantly increased CD31hiEMCNhi endothelial cells (ECs) and SLIT3 and HIF‐1α expression levels in co‐cultured HUVECs and hDPSCs. Knockdown of Slit3 in hDPSCs or Hif‐1α in HUVECs impaired the formation of CD31hiEMCNhi ECs and reversed TPPU‐induced osteogenesis. We defined a previously unidentified effect of TPPU coupling angiogenesis and osteogenesis. TPPU induced type H vessels by upregulating the expression of hDPSCs‐derived SLIT3, which resulted in the activation of ROBO1/YAP1/HIF‐1α signalling pathway in ECs. Targeting metabolic pathways of EETs represents a new strategy to couple osteogenesis and angiogenesis, sEH is a promising therapeutic target for bone regeneration and repair.

Inhibition of soluble epoxide hydrolase enhances the dentin-pulp complex regeneration mediated by crosstalk between vascular endothelial cells and dental pulp stem cells

“…Exogenous systemic administration of EETs also promotes liver regeneration in mice [ 12 ]. Our previous experiments also confirmed that EETs enhance the formation of new bone, collagen fibers and vascular structures in a mouse calvarial defect model [ 13 ]. However, it has not been reported whether EETs can promote the coupling of angiogenesis and odontogenesis, thereby promoting pulp tissue regeneration.…”

“…Our in vitro results suggested that HIF-1α plays a pivotal role in POTCs. Recently, we have demonstrated that TPPU increases HIF-1α levels in cocultured HUVECs and hDPSCs by activating SLIT3 in hDPSCs [ 13 ]. HIF-1α, as a transcription factor, could regulate the expression of VEGF and TGF-β [ 42 , 43 ].…”

“…TPPU (MedChemExpress, NJ, USA) was dissolved in DMSO (10 mg/ml) and stored at − 20 °C according to the manufacturer’s instructions. TPPU stock solution was added into medium (the final concentration of TPPU was 10 μM) for in vitro cell treatment as previously described [ 13 , 19 ]. For in vivo study, TPPU stock solution (10 mg/ml dissolved in DMSO) was formulated in 20% (vol/vol) PEG 400 (MedChemExpress, the final concentration of TPPU was 1 mg/ml).…”

Inhibition of soluble epoxide hydrolase induces POTCs to enhance the dentin-pulp complex regeneration mediated by crosstalk between vascular endothelial cells and dental pulp stem cells

“…Our in vitro and in vivo results suggested that HIF-1α plays a pivotal role in POTCs. Recently, we have demonstrated that TPPU increases HIF-1α levels in cocultured HUVECs and hDPSCs by activating SLIT3 in hDPSCs [13]. Here, we further showed that TPPU-upregulated HIF-1α is also involved in odontogenesis and angiogenesis with increased expression of VEGFR2 in ECs and TGF-β, DSPP, and DMP-1 in MSCs.…”

“…Exogenous systemic administration of EETs also promotes liver regeneration in mice [12]. Our previous experiments also con rmed that EETs enhance the formation of new bone, collagen bers and vascular structures in a mouse calvarial defect model [13]. However, it has not been reported whether EETs can promote the coupling of angiogenesis and odontogenesis, thereby promoting pulp tissue regeneration.…”