Psoralidin prevents caffeine-induced damage and abnormal differentiation of bone marrow mesenchymal stem cells via the classical estrogen receptor pathway

BACKGROUND: Caffeine is broadly present in tea, coffee, and cocoa, and is commonly consumed. The bone microenvironment might be damaged by excessive caffeine, which has been shown to exert negative effects on human health. In this study, we sought to determine whether excessive caffeine could damage the biological functions of bone marrow mesenchymal stem cells (BMSCs) and induce bone loss in mice, and further investigate effective therapeutic methods. METHODS: BMSCs were treated with different concentrations of caffeine (0.01, 0.05, 0.1, 0.5, and 1.0 mM) for 48 h. Cell counting kit-8 (CCK-8) assay, colony formation assay, wound healing assay, and quantitative real-time polymerase chain reaction (qRT-PCR) analysis were performed to detect the cell viability, proliferation, migration, and pluripotency of BMSCs, respectively. Alizarin red S (ARS) staining, alkaline phosphatase (ALP) staining, oil red O (ORO) staining, and qRT-PCR assay were applied to assess the osteogenic and adipogenic differentiation of BMSCs. BMSCs were treated with caffeine and further exposed to different concentrations of psoralidin (PL) (0.01, 0.1, 1, and 10 µM) for 48 h. Micro-computed tomography (µCT) scanning was used to evaluate the bone mass of mice. 7α-(7-((4,4,5,5,5-Pentafluoropentyl)-sulfiny)nonyl)estra-1,3,5(10)-triene-3,17β-diol (ICI 182,780, ICI) was applied to examine whether the classical estrogen receptor (ER) pathway was involved. RESULTS: The CCK-8 assay, colony formation assay, wound healing assay, and qRT-PCR analysis indicated that caffeine (0.01, 0.05, 0.1, 0.5, 1.0 mM) attenuated the cell viability, proliferation, migration and pluripotency of BMSCs, respectively, in a concentration-dependent manner. Caffeine treatment inhibited osteogenic differentiation but promoted adipogenic differentiation of BMSCs in a dose-dependent manner. Furthermore, ARS staining, ALP staining, ORO staining, and qRT-PCR assay showed that excessive caffeine induced bone loss and osteoporosis (OP) in mice by regulating the osteogenesis and adipogenesis of BMSCs. Also, PL treatment could reverse the caffeine-induced dysfunctions and aberrant differentiation of BMSCs via the ER pathway. CONCLUSIONS: Our results revealed a novel molecular mechanism for the therapeutic effects of PL in treating excessive caffeine-induced OP, which might shed new light on the clinical application of PL for caffeine-related OP.