Icariin regulates the osteoblast differentiation and cell proliferation of MC3T3-E1 cells through microRNA-153 by targeting Runt-related transcription factor 2

Role of microRNA in Diabetic Osteoporosis

Diabetic osteoporosis (DOP), a complication associated with diabetes mellitus (DM), is a metabolic bone disorder characterized by a reduction in bone mass per unit volume, impaired bone tissue microarchitecture, heightened bone fragility, and increased susceptibility to fractures. Individuals with diabetes exhibit a significantly greater incidence of osteoporosis and related fractures than those without diabetes. These fractures present a significant challenge in terms of the healing process and can result in severe consequences, including fatalities. MicroRNAs (miRNAs), a class of noncoding RNAs, play a pivotal role in numerous human diseases and are implicated in the pathogenesis of DOP. This review initially elucidates the essential role of miRNAs in the pathogenesis of DOP. Next, we emphasize the potential significance of miRNAs as valuable biomarkers for diagnosing DOP and predicting DOP-related fractures. Furthermore, we explore the involvement of miRNAs in managing DOP through various pathways, including conventional pharmaceutical interventions and exercise therapy. Importantly, miRNAs exhibit potential as targeted therapeutic agents for effectively treating DOP. Finally, we highlight the use of novel materials and exosomes for miRNA delivery, which has significant advantages in the treatment of DOP and overcomes the limitations associated with miRNA delivery.

Emerging Natural-Product-Based Treatments for the Management of Osteoarthritis

Osteoarthritis (OA) is a complex degenerative disease in which joint homeostasis is disrupted, leading to synovial inflammation, cartilage degradation, subchondral bone remodeling, and resulting in pain and joint disability. Yet, the development of new treatment strategies to restore the equilibrium of the osteoarthritic joint remains a challenge. Numerous studies have revealed that dietary components and/or natural products have anti-inflammatory, antioxidant, anti-bone-resorption, and anabolic potential and have received much attention toward the development of new therapeutic strategies for OA treatment. In the present review, we provide an overview of current and emerging natural-product-based research treatments for OA management by drawing attention to experimental, pre-clinical, and clinical models. Herein, we review current and emerging natural-product-based research treatments for OA management.

Let-7i-5p functions as a putative osteogenic differentiation promoter by targeting CKIP-1

MicroRNA (miRNA) is an endogenous regulatory small molecule RNA. Growing evidence shows that miRNA plays an important regulatory role in gene expression. Although miRNA is a more intensive regulatory noncoding RNA in recent years, few studies have investigated the regulation of targeting genes involved in bone repair. Meanwhile, as a negative bone regulator, previous studies showed that casein kinase 2-interacting protein 1 (CKIP-1) is closely associated with bone formation and regeneration. However, the gene knockout method may not be suitable for clinical application. Therefore, it was hypothesized that miRNA molecules can inhibit the expression of CKIP-1 and ultimately promote the osteogenesis process. The present study revealed that let-7i-5p plays an important role in the process of fracture healing by inhibiting the expression of CKIP-1. Related research provides a novel gene target for fracture healing.

Supplementary information

The online version of this article (10.1007/s10616-020-00444-1) contains supplementary material, which is available to authorized users.

Icariin-Functionalized Nanodiamonds to Enhance Osteogenic Capacity In Vitro

Nanodiamonds (NDs) have been used as drug delivery vehicles due to their low toxicity and biocompatibility. Recently, it has been reported that NDs have also osteogenic differentiation capacity. However, their capacity using NDs alone is not enough. To significantly improve their osteogenic activity, we developed icariin (ICA)-functionalized NDs (ICA-NDs) and evaluated whether ICA-NDs enhance their in vitro osteogenic capacity. Unmodified NDs and ICA-NDs showed nanosized particles that were spherical in shape. The ICA-NDs achieved a prolonged ICA release for up to 4 weeks. The osteogenic capacities of NDs, ICA (10 μg)-NDs, and ICA (50 μg)-NDs were demonstrated by alkaline phosphatase (ALP) activity; calcium content; and mRNA gene levels of osteogenic-related markers, including ALP, runt-related transcript factor 2 (RUNX2), collagen type I alpha 1 (COL1A1), and osteopontin (OPN). In vitro cell studies revealed that ICA (50 μg)-ND-treated MC3T3-E1 cells greatly increased osteogenic markers, including ALP, calcium content, and mRNA gene levels of osteogenic-related markers, including ALP, RUNX2, COL1A1, and OPN compared to ICA (10 μg)-NDs or ND-treated cells. These our data suggest that ICA-NDs can promote osteogenic capacity.

Investigating the In Vitro Osteogenic Properties of the Inclusion Nanocarrier of Icariin with Beta-Cyclodextrin-Alginate

In this study, we created an inclusion nanocarrier of icariin (ICA) and β-cyclodextrin-alginate conjugate (ICA/β-CD-ALG) and determined its in vitro osteogenic ability on MC3T3-E1 cells. The morphological shape of the prepared β-CD-ALG with or without ICA was nano-sized and round. The use of β-CD-ALG achieved a sustained ICA release for up to 7 days. In vitro studies found that ICA/β-CD-ALG had a greater potential in osteogenesis on MC3T3-E1 cells compared to β-CD-ALG by exhibiting both higher alkaline phosphatase levels and the amount of calcium deposits. Moreover, ICA/β-CD-ALG greatly increased the levels of osteogenesis markers including osteocalcin (OCN) and osteopontin (OPN). Our results suggest that ICA/β-CD-ALG plays a significant role in cellular osteogenic activity.

Icariin promotes osteogenic differentiation of BMSCs by upregulating BMAL1 expression via BMP signaling

Increasing research has demonstrated that expression of brain and muscle ARNT‑like 1 (BMAL1) and other circadian clock genes can be regulated by drugs and toxicants. We previously demonstrated that icariin, extracted from Herba Epimedii, sromotes osteogenic differentiation. However, the mechanism underlying the association between icariin and BMAL1 in osteogenic differentiation of bone marrow‑derived mesenchymal stem cells (BMSCs) remains unclear. The present study was designed with an aim to clarify the association between icariin and BMAL1 in osteogenic differentiation of BMSCs. The Cell Counting Kit‑8 assay was used to evaluate cell proliferation. The expression of bone morphogenetic protein 2 (BMP2), RUNX family transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteocalcin (OC) and BMAL1 in BMSCs was evaluated by reverse transcription‑quantitative PCR and western blotting. ALP and Alizarin red S (ARS) staining were also performed. Icariin promoted BMSC proliferation, and upregulated expression of osteogenic genes and BMAL1. In addition, expression of the osteogenic genes BMP2, RUNX2, ALP and OC were upregulated by BMAL1 overexpression. Furthermore, we confirmed that BMAL1 deficiency suppressed osteogenic differentiation in BMSCs. Finally, ARS staining of BMAL1‑/‑ BMSCs revealed that BMAL1 was an essential intermediary in matrix mineralization during osteogenic differentiation. In conclusion, these results demonstrated that icariin promoted osteogenic differentiation through BMAL1‑BMP2 signaling in BMSCs. The present study thus described a novel target of icariin that has potential applications in the treatment of osteogenic disorders.

[Effect of icariin on early steroid-induced osteonecrosis of the femoral head in rabbits]

Objective

To explore the effect of icariin on early steroid-induced osteonecrosis of the femoral head in rabbits.

Methods

Fifty mature New Zealand rabbits (weighing, 2.5-3.0 kg) were randomly divided into control group ( n=10), model group ( n=20), and experimental group ( n=20). The rabbits of model and experimental groups were injected with lipopolysaccharide and methylprednisolone to establish the animal model of early steroid-induced osteonecrosis of the femoral head. The rabbits of experimental group were feeded with icariin solution once a day for 6 weeks since the first injection of methylprednisolone, whereas the rabbits of control and model groups were given normal saline at the same time points. The left femoral heads were removed after 6 weeks and gross morphological features were evaluated. Micro-CT scan was performed to analyze the trabecular microstructure with the following parameters: trabecular bone volume to total volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Tn), and trabecular separation (Tb.Sp). The Micro-CT scan was also converted to three-dimensional reconstruction images for observation. HE staining was applied to observe the trabecular structure and morphological changes of osteocytes and marrow adipocytes. It was also used to determine whether the samples of femoral heads occurred osteonecrosis based on the criteria for pathological diagnosis, and calculate the rate of empty lacunae.

Results

Seven rabbits died during the study, and 9, 16, and 18 rabbits in the control, model, and experimental groups, respectively, enrolled the final analysis. Compared with control group, the femoral head collapse and trabecular breaks were more obvious, and the trabeculae were sparse with irregular arrangement in the model group according to the results of gross observation, Micro-CT scan, and three-dimensional reconstruction images. But in the experimental group, the surface of femoral head was slight shrinking without obvious collapse, and the degeneration of trabecular structure was mild. According to bone microstructures analysis, the Tb.N, Tb.Tn, and BV/TV of femoral head in model and experimental groups were lower than those in control group, while the Tb.Sp in the model and experimental groups were significantly higher. The Tb.N, Tb.Tn, and BV/TV of femoral head in experimental group were higher than those in model group, while the Tb.Sp in the experimental group was significantly lower. The differences between groups were all significant ( P<0.05). In the model group, HE staining showed that the number of osteocytes reduced, the number of empty lacunae increased, and the marrow adipocytes piled up in the space between femoral trabeculae, some even mashed together like a cyst. In the experimental group, the trabecular structure was still relatively complete compared with model group, no obvious apoptosis of osteocytes was observed, the size and number of adipocytes were basically normal. None of the animals in control group occurred osteonecrosis of the femoral head based on the criteria for pathological diagnosis, and the incidence of osteonecrosis were 81.3% (13/16) in the model group and 66.7% (12/18) in the experimental group, and the difference was not significant ( P=0.448). The rate of empty lacunae of osteonecrotic femoral heads in the model group was 33.1%±1.4%, which was higher than that in experimental group (18.9%±0.8%) and in control group (12.7%±1.5%), and the differences between groups were significant ( P<0.05).

Conclusion

The icariin has a protective effect on the early steroid-induced osteonecrosis of the femoral head in rabbits, which can decrease osteocytes apoptosis, improve the bone microstructure, and delay such disease processes.

Baicalin augments the differentiation of osteoblasts via enhancement of microRNA-217

Baicalin (BAI), a sort of flavonoid monomer, acquires from Scutellaria baicalensis Georgi, which was forcefully reported in diversified ailments due to the pleiotropic properties. But, the functions of BAI in osteoblast differentiation have not been addressed. The intentions of this study are to attest the influences of BAI in the differentiation of osteoblasts. MC3T3-E1 cells or rat primary osteoblasts were exposed to BAI, and then cell viability, ALP activity, mineralization process, and Runx2 and Ocn expression were appraised through implementing CCK-8, p-nitrophenyl phosphate (pNPP), Alizarin red staining, western blot, and RT-qPCR assays. The microRNA-217 (miR-217) expression was evaluated in MC3T3-E1 cells or rat primary osteoblasts after BAI disposition; meanwhile, the functions of miR-217 in BAI-administrated MC3T3-E1 cells were estimated after miR-217 inhibitor transfection. The impacts of BAI and miR-217 inhibition on Wnt/β-catenin and MEK/ERK pathways were probed to verify the involvements in BAI-regulated the differentiation of osteoblasts. BAI accelerated cell viability, osteoblast activity, and Runx2 and Ocn expression in MC3T3-E1 cells or rat primary osteoblasts, and the phenomena were mediated via activations of Wnt/β-catenin and MEK/ERK pathways. Elevation of miR-217 was observed in BAI-disposed MC3T3-E1 cells or rat primary osteoblasts, and miR-217 repression annulled the functions of BAI in MC3T3-E1 cell viability and differentiation. Additionally, the activations of Wnt/β-catenin and MEK/ERK pathways evoked by BAI were both restrained by repression of miR-217. These explorations uncovered that BAI augmented the differentiation of osteoblasts via activations of Wnt/β-catenin and MEK/ERK pathways by ascending miR-217 expression.

Modulatory Effects of Plant Polyphenols on Bone Remodeling: A Prospective View From the Bench to Bedside

During the past, a more comprehensive knowledge of mechanisms implicated in bone resorption processes has driven researchers to develop a compound library of many small molecules that specifically interfere with the genesis of osteoclast precursors cells. Natural compounds that suppress osteoclast commitment may have therapeutic value in treating pathologies associated with bone resorption like osteoporosis, rheumatoid arthritis, bone metastasis, and periodontal disease. The present review is focused on the current knowledge on the polyphenols derived from plants that could be efficacious in suppressing osteoclast differentiation and bone resorption.

Effects of Icariin on Atherosclerosis and Predicted Function Regulatory Network in ApoE Deficient Mice

Objective. Icariin plays a pivotal role in ameliorating atherosclerosis for animal models although its comprehensive biological role remains largely unexplored. This study aimed to fully understand the effects of icariin on atherosclerosis in high-fat diet-induced ApoE^-/- mice and investigate mRNA-miRNA regulation based on microarray and bioinformatics analysis. Methods. The areas of atherosclerotic lesions in en face aorta were evaluated. Microarray analysis was performed on atherosclerotic aortic tissues. The integrative analysis of mRNA and miRNA profiling was utilized to suggest specific functions of gene and supply an integrated and corresponding method to study the protective effect of icariin on atherosclerosis. Results. Icariin attenuated the development of atherosclerosis that the mean atherosclerotic lesion area was reduced by 5.8% (P < 0.05). Significant changes were observed in mRNA and miRNA expression patterns. Several miRNAs obtained from the miRNA-Gene-Network might play paramount part in antiatherosclerotic effect of icariin, such as mmu-miR-6931-5p, mmu-miR-3547-5p, mmu-miR-5107-5p, mmu-miR-6368, and mmu-miR-7118-5p. Specific miRNAs and GO terms associated with icariin in the pathogenesis of atherosclerosis were validated using GO analysis and miRNA-GO-Network. MiRNA-Pathway-Network indicated that icariin induced miRNAs mainly regulate the signaling pathways of PI3K/Akt signaling pathway, Ras signaling pathway, ErbB signaling pathway, and VEGF signaling pathway in aorta atherosclerotic lesion. Conclusions. Our data provides evidence that icariin is able to exhibit one antiatherosclerotic action by mediating multiple biological processes or cascades, suggesting the pleiotropic effects of icariin in atherosclerosis alleviation. The identified gene functional categories and pathways are potentially valuable targets for future development of RNA-guided gene regulation to fight disease.