Isopsoralen-mediated suppression of bone marrow adiposity and attenuation of the adipogenic commitment of bone marrow-derived mesenchymal stem cells

Abstract

Osteoporosis (OP) increases the risk of bone fractures and other complications, and is thus a major clinical problem. In this study, we examined the effect of isopsoralen on the differentiation of bone-derived marrow mesenchymal stem cells (BMSCs) into osteoblasts and adipocytes, as well as bone formation under osteoporotic conditions. Primary femoral BMSCs isolated from C57BL/6 mice were used to evaluate the isopsoralen-mediated regulation of the expression of alkaline phosphatase (ALP), osteocalcin (OCN) and runt-related transcription factor 2 (RUNX2) during osteogenesis 2 weeks. We also examined the expression of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein β (C/EBPβ) under adipogenic conditions for 1 and 2 weeks. In addition, ovariectomized (OVX) mice were used to examine the effects of isopsoralen on bone formation for 2 months. Finally, mammalian target of rapamycin complex 1 (mTORC1) signaling was examined under osteogenic and adipogenic conditions. We found that following treatment with isopsoralen, the expression levels of ALP, OCN and RUNX2 were upregulated, whereas those of PPARγ and C/EBPβ were downregulated. mTORC1 signaling was also inhibited in vitro and in vivo. In the OVX mice that were intragastrically administered isopsoralen, bone parameters (trabecular thickness, bone volume/total volume and trabecular number) in the distal femoral metaphysis were significantly increased and the adipocyte number was decreased. On the whole, our findings demonstrate that isopsoralen promoted BMSC differentiation into osteoblasts and suppressed differentiation into adipocytes.

Angelicin—A Furocoumarin Compound With Vast Biological Potential

“…However, in a recent paper, Ge et al (2019) had demonstrated that angelicin was able to not only increase the proliferation of osteoblast but also to induce the expression of alkaline phosphatase (ALP) after 7 days of treatment while the matrix mineralization of the cells can be seen on the 12 th day of treatment with angelicin. Similar observation of increased cell proliferation, ALP activity and mineralization of osteoblasts by angelicin were reported in MC3T3-E1 (mouse osteoblast precursor) cells and primary bone marrow mesenchymal stem cells (BMSC) with the exception that BMSC cells did not experience any changes in cell proliferation (Wang et al, 2017b;Ge et al, 2018).…”

“…In addition, two markers from the mTOR complex 1 (mTORC1) signaling pathway, p-S6 and p-4EBP1, were analyzed in both osteogenic and adipogenic conditions. When comparing the two markers, p-S6 showed marked downregulation in expression while p-4EBP1 was upregulated under both differentiation conditions for 7 and 14 days (Wang et al, 2017b). mTOR is a conserved pathway that plays a role in regulating cell growth and metabolism and it had been reported that mTORC1 participates in adipogenesis (Polak et al, 2008;Betz and Hall, 2013).…”

“…Significant decrease in the number of adipocytes in the bone marrow after treatment with angelicin 3. Significant increase in the trabecular thickness (Tb.Th), bone volume/total volume (BV/TV) and trabecular number (Tb.N) in mouse distal femur after treatment with angelicin (Wang et al, 2017b) 1. MC3T3-E1 cells 2.…”

“…In both the primary bone marrow mesenchymal stem cells (BMSC) (obtained from 4 week old C57BL/6 mice) as well as primary rat osteoblasts cells (obtained from female Winstar rats) that were treated with angelicin, significant increases in BMP-2, Runx2, OCN, and b -catenin were reported in multiple studies (Wang et al, 2017b;Ge et al, 2019). Using immunofluorescence staining, it was also revealed that not only was b-catenin upregulated by angelicin, there was also an increase in b-catenin translocation into the nucleus after treatment (Ge et al, 2019).…”

“…Other than that, angelicin was also discovered to suppress the conversion of BMSC to adipocytes. The study by Wang et al (2017b), reported an angelicin induced dose-dependent downregulation in PPARg and C/EBPb adipocyte-specific markers in adipogenesis differentiation while osteogenic markers, Runx2 and OCN were dose-dependently increased in osteogenic differentiation. In addition, two markers from the mTOR complex 1 (mTORC1) signaling pathway, p-S6 and p-4EBP1, were analyzed in both osteogenic and adipogenic conditions.…”