Morinda officinalis polysaccharide enable suppression of osteoclastic differentiation by exosomes derived from rat mesenchymal stem cells

Morinda Officinalis-derived extracellular vesicle-like particles: Anti-osteoporosis effect by regulating MAPK signaling pathway

BACKGROUND

Postmenopausal osteoporosis (PMOP) is a systemic bone disease characterized by low bone mass and microstructural damage. Morinda Officinalis (MO) contains various components with anti-PMOP activities. Morinda Officinalis-derived extracellular vesicle-like particles (MOEVLPs) are new active components isolated from MO, and no relevant studies have investigated their anti-osteoporosis effect and mechanism.

PURPOSE

To investigate the alleviating effect of MOEVLPs on PMOP and the underlying mechanism.

METHODS

Differential centrifugation and ultracentrifugation were used to isolate MOEVLPs from MO. Transmission electron microscopy (TEM), flow nano analyzer, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), agarose gel electrophoresis, and thin-layer chromatography were employed to characterize MOEVLPs. PMOP mouse models were utilized to examine the anti-PMOP effect of MOEVLPs. H&E and immunohistochemical staining were used for drug safety and osteogenic effect assessment. Mouse embryo osteoblast precursor cells (MC3T3-E1) were used in vitro experiments. CCK-8 kit, alizarin red staining, proteomic, bioinformatic analyses, and western blot were used to explore the mechanism of MOEVLPs.

RESULTS

In this study, MOEVLPs from MO were successfully isolated and characterized. Animal experiments demonstrated that MOEVLPs exhibited specific femur targeting, were non-toxic to the heart, liver, spleen, lung, kidney, and aorta, and possessed anti-PMOP properties. The ability of MOEVLPs to strengthen bone formation was better than that of alendronate. In vitro experiments, results revealed that MOEVLPs did not significantly enhance osteogenic differentiation in MC3T3-E1 cells. Instead, MOEVLPs promoted the proliferation of MC3T3-E1 cells. Proteomic and bioinformatic analyses suggested that the proliferative effect of MOEVLPs was closely associated with the mitogen-activated protein kinase (MAPK) signaling pathway, particularly the altered expression of cAMP response element-binding protein (CREB) and ribosomal S6 kinase 1 (RSK1). Western blot results further confirmed these findings.

CONCLUSION

Our studies successfully isolated high-quality MOEVLPs and demonstrated that MOEVLPs can alleviate PMOP by promoting osteoblast proliferation through the MAPK pathway. MOEVLPs have the potential to become a novel and natural anti-PMOP drug.

The Potential of Exosomes for Osteoporosis Treatment: A Review

As a continuous process comprising bone resorption and formation, bone remodeling, plays an essential role in maintaining the balance of bone metabolism. One type of metabolic osteopathy is osteoporosis, which is defined by low bone mass and deteriorating bone microstructure. Osteoporosis patients are more likely to experience frequent osteoporotic fractures, which makes osteoporosis prevention and treatment crucial. A growing body of research has revealed that exosomes, which are homogenous vesicles released by most cell types, play a major role in mediating a number of pathophysiological processes, including osteoporosis. Exosomes may act as a mediator in cell-to-cell communication and offer a fresh perspective on information sharing. This review discusses the characteristics of exosomes and outlines the exosomes' underlying mechanism that contributes to the onset of osteoporosis. Recent years have seen a rise in interest in the role of exosomes in osteoporosis, which has given rise to innovative therapeutic approaches for the disease prevention and management.

Wen-Shen-Tong-Luo-Zhi-Tong Decoction regulates bone-fat balance in osteoporosis by adipocyte-derived exosomes

CONTEXT

Wen-Shen-Tong-Luo-Zhi-Tong (WSTLZT) Decoction is a Chinese prescription with antiosteoporosis effects, especially in patients with abnormal lipid metabolism.

OBJECTIVE

To explore the effect and mechanism of WSTLZT on osteoporosis (OP) through adipocyte-derived exosomes.

MATERIALS AND METHODS

Adipocyte-derived exosomes with or without WSTLZT treated were identified by transmission electron microscopy, nanoparticle tracking analysis (NTA) and western blotting (WB). Co-culture experiments for bone marrow mesenchymal stem cells (BMSCs) and exosomes were performed to examine the uptake and effect of exosome in osteogenesis and adipogenic differentiation of BMSC. MicroRNA profiles, luciferase and IP were used for exploring specific mechanisms of exosome on BMSC. In vivo, 80 Balb/c mice were randomly divided into four groups: Sham, Ovx, Exo (30 μg exosomes), Exo-WSTLZT (30 μg WSTLZT-exosomes), tail vein injection every week. After 12 weeks, the bone microstructure and marrow fat distribution were analysed by micro-CT.

RESULTS

ALP, Alizarin red and Oil red staining showed that WSTLZT-induced exosomes from adipocyte can regulate osteoblastic and adipogenic differentiation of BMSC. MicroRNA profiles observed that WSTLZT treatment resulted in 87 differentially expressed miRNAs (p < 0.05). MiR-122-5p with the greatest difference was screened by q-PCR (p < 0.01). The target relationship between miR-122-5p and SPRY2 was tested by luciferase and IP. MiR-122-5p negatively regulated SPRY2 and elevated the activity of MAPK signalling pathway, thereby regulating the osteoblastic and adipogenic differentiation of BMSC. In vivo, exosomes can not only improve bone microarchitecture but also significantly reduce accumulation of bone marrow adipose.

CONCLUSIONS

WSTLZT can exert anti-OP effect through SPRY2 via the MAKP signalling by miR-122-5p carried by adipocyte-derived exosomes.

Rubiadin-1-methyl ether inhibits BECN1 transcription and Beclin1-dependent autophagy during osteoclastogenesis by inhibiting NF-κB p65 activation

As an active substance isolated from the root of Morinda officinalis How., rubiadin-1-methyl ether (RBM), can improve osteoporosis due to its inhibition on osteoclastogenesis. Autophagy plays a key role in osteoclastogenesis. Our research aims to explore the relationship between RBM, autophagy, and osteoclastogenesis. Our results showed that RBM not only inhibited the differentiation level of osteoclasts and the proliferation ability of osteoclast precursors (OCPs), but also repressed the autophagic activity in OCPs (LC3 transformation and the number of autophagosomes observed by transmission electron microscopy). However, RBM-inhibited osteoclast differentiation and OCP autophagy (LC3 transformation and LC3-puncta formation) could be reversed by the application of TAT-Beclin1. Moreover, RBM administration reduced RANKL-induced p65 phosphorylation and p65 nuclear translocation in OCPs. In addition, the addition of RBM inhibited Beclin1 protein level and BECN1 (the gene form of Beclin1) mRNA level in OCPs increased by RANKL. Importantly, the reduction in the expression of BECN1 and Beclin1, LC3 transformation, and osteoclastic differentiation in OCPs caused by RBM were reversed by p65 overexpression. In conclusion, RBM may reduce the transcription of BECN1 by inhibiting the activation of nuclear factor kappa B (NF-κB) p65, thereby inhibiting Beclin1-dependent autophagy and RANKL-induced osteoclastogenesis.

New insights into the role of long non-coding RNAs in osteoporosis

Osteoporosis is a common disease in elderly individuals, and osteoporosis can easily lead to bone and hip fractures that seriously endanger the health of elderly individuals. At present, the treatment of osteoporosis is mainly anti-osteoporosis drugs, but there are side effects associated with anti-osteoporosis drugs. Therefore, it is very important to develop early diagnostic indicators and new therapeutic drugs for the prevention and treatment of osteoporosis. Long noncoding RNAs (lncRNAs), noncoding RNAs longer than 200 nucleotides, can be used as diagnostic markers for osteoporosis, and lncRNAs play an important role in the progression of osteoporosis. Many studies have shown that lncRNAs can be the target of osteoporosis. Therefore, herein, the role of lncRNAs in osteoporosis is summarized, aiming to provide some information for the prevention and treatment of osteoporosis.

Mechanisms by which kidney-tonifying Chinese herbs inhibit osteoclastogenesis: Emphasis on immune cells

The immune system plays a crucial role in regulating osteoclast formation and function and has significance for the occurrence and development of immune-mediated bone diseases. Kidney-tonifying Chinese herbs, based on the theory of traditional Chinese medicine (TCM) to unify the kidney and strengthen the bone, have been widely used in the prevention and treatment of bone diseases. The common botanical drugs are tonifying kidney-yang and nourishing kidney-yin herbs, which are divided into two parts: one is the compound prescription of TCM, and the other is the single preparation of TCM and its active ingredients. These botanical drugs regulate osteoclastogenesis directly and indirectly by immune cells, however, we have limited information on the differences between the two botanical drugs in osteoimmunology. In this review, the mechanism by which kidney-tonifying Chinese herbs inhibiting osteoclastogenesis was investigated, emphasizing the immune response. The differences in the mechanism of action between tonifying kidney-yang herbs and nourishing kidney-yin herbs were analysed, and the therapeutic value for immune-mediated bone diseases was evaluated.