Physcion-8-O-beta-D-glucopyranoside enhances the commitment of mouse mesenchymal progenitors into osteoblasts and their differentiation: Possible involvement of signaling pathways to activate BMP gene expression

Water extract of Rumex crispus prevents bone loss by inhibiting osteoclastogenesis and inducing osteoblast mineralization

Background

Rumex crispus root has traditionally been used in Asian medicine for the treatment of hemorrhage and dermatolosis. The aim of this study was to explore the pharmaceutical effects of water extract of Rumex crispus (WERC) on osteoblast and osteoclast differentiation. We also studied the effect of WERC on the receptor activator of nuclear factor kappa-B ligand (RANKL)-induced trabecular bone destruction mice model.

Methods

High performance liquid chromatography analysis was used to identify three compounds (emodin, chrysophanol, and physcion) of WERC. The in vivo effect of WERC was examined using an administration of WERC or vehicle on the ICR mice with bone loss induced by intraperitoneal RANKL injection on day 0 and 1. All mice were sacrificed by cervical dislocation at day 7 and the femurs of mice were isolated for soft X-ray and Micro-CT analysis. The in vitro effect of WERC on osteoblast mineralization or osteoclast differentiation was examined by alizarin red S staining or by tartrate-resistant acid phosphatase staining and assay. To determine the transcription level of osteoblast or osteoclast-specific genes, real-time quantitative polymerase chain reaction was used. Western blot analysis was performed to study the effect of WERC on mitogen-activated protein kinases (MAPK) or nuclear factor-κB (NF-κB) signaling molecules.

Results

The presence of three compounds in WERC was determined. WERC significantly suppressed RANKL-induced trabecular bone loss by preventing microstructural deterioration. In vitro, WERC increased osteoblast mineralization by enhancing the transcription of runt-related transcription factor 2 and its transcriptional coactivators, and by stimulating extracellular signal–regulated kinase phosphorylation. Furthermore, WERC significantly inhibited osteoclast differentiation by suppressing the activation of the RANKL signalings (MAPK and NF-κB) and the increasing inhibitory factors of nuclear factor of activated T cells cytoplasmic 1.

Conclusion

This study showed that WERC could protect against osteoporosis and suggested that the possible mechanism of WERC might be related to increased osteoblast differentiation by activating Runx2 signaling and inhibition of osteoclast differentiation by suppression of RANKL signaling.

Electronic supplementary material

The online version of this article (10.1186/s12906-017-1986-7) contains supplementary material, which is available to authorized users.

Emodin prevents hypoxic-ischemic neuronal injury: Involvement of the activin A pathway

Emodin, an extract of dried rhizomes and the root of the Rhizoma Polygoni Cuspidati, can protect neurons from hypoxic-ischemic brain damage. This study aimed to verify the underlying mechanism. After PC12 cells had differentiated into neuron-like cells under the induction of mouse nerve growth factor, cells were subjected to oxygen-glucose deprivation and treated with emodin. Results showed that the viability of neuron-like cells cultured under an ischemia-hypoxia environment decreased, while the expression of activin A and caspase-3 in cells increased. Emodin raised the survival rate of oxygen-glucose deprived neuron-like cells, increased activin A expression, and decreased caspase-3 expression. Experimental findings indicate that emodin can inhibit neuronal apoptosis and alleviate the injury of nerve cells after oxygen-glucose deprivation through the activin A pathway.

Indacaterol inhibits tumor cell invasiveness and MMP-9 expression by suppressing IKK/NF-κB activation

The β2 adrenergic receptor (ADRB2) is a G protein-coupled transmembrane receptor expressed in the human respiratory tract and widely recognized as a pharmacological target for treatments of asthma and chronic obstructive pulmonary disorder (COPD). Although a number of ADRB2 agonists have been developed for use in asthma therapy, indacaterol is the only ultra-long-acting inhaled β2-agonist (LABA) approved by the FDA for relieving the symptoms in COPD patients. The precise molecular mechanism underlying the pharmacological effect of indacaterol, however, remains unclear. Here, we show that β-arrestin-2 mediates the internalization of ADRB2 following indacaterol treatment. Moreover, we demonstrate that indacaterol significantly inhibits tumor necrosis factor-α (TNF-α)-induced NF-κB activity by reducing levels of both phosphorylated-IKK and -IκBα, thereby decreasing NF-κB nuclear translocation and the expression of MMP-9, an NF-κB target gene. Subsequently, we show that indacaterol significantly inhibits TNF-α/NF-κB-induced cell invasiveness and migration in a human cancer cell line. In conclusion, we propose that indacaterol may inhibit NF-κB activity in a β-arrestin2-dependent manner, preventing further lung damage and improving lung function in COPD patients.