Pluripotent mesenchymal stem cells (MSCs) are bone marrow stromal progenitor cells that can differentiate into osteogenic, chondrogenic, adipogenic, and myogenic lineages. Several signaling pathways have been shown to regulate the lineage commitment and terminal differentiation of MSCs. Here, we conducted a comprehensive analysis of the 14 types of bone morphogenetic protein (BMPs) for their abilities to regulate multilineage specific differentiation of MSCs. We found that most BMPs exhibited distinct abilities to regulate the expression of Runx2, Sox9, MyoD, and PPARγ2. Further analysis indicated that BMP-2, BMP-4, BMP-6, BMP-7, and BMP-9 effectively induced both adipogenic and osteogenic differentiation in vitro and in vivo. BMP-induced commitment to osteogenic or adipogenic lineage was shown to be mutually exclusive. Overexpression of Runx2 enhanced BMP-induced osteogenic differentiation, whereas knockdown of Runx2 expression diminished BMP-induced bone formation with a decrease in adipocyte accumulation in vivo. Interestingly, overexpression of PPARγ2 not only promoted adipogenic differentiation, but also enhanced osteogenic differentiation upon BMP-2, BMP-6, and BMP-9 stimulation. Conversely, MSCs with PPARγ2 knockdown or mouse embryonic fibroblasts derived from PPARγ2−/− mice exhibited a marked decrease in adipogenic differentiation, coupled with reduced osteogenic differentiation and diminished mineralization upon BMP-9 stimulation, suggesting that PPARγ2 may play a role in BMP-induced osteogenic and adipogenic differentiation. Thus, it is important to understand the molecular mechanism behind BMP-regulated lineage divergence during MSC differentiation, as this knowledge could help us to understand the pathogenesis of skeletal diseases and may lead to the development of strategies for regenerative medicine.
Promoting osteogenic differentiation and efficacious bone regeneration have the potential to revolutionize the treatment of orthopaedic and musculoskeletal disorders. Mesenchymal Stem Cells (MSCs) are bone marrow progenitor cells that have the capacity to differentiate along osteogenic, chondrogenic, myogenic, and adipogenic lineages. Differentiation along these lineages is a tightly controlled process that is in part regulated by the Bone Morphogenetic Proteins (BMPs). BMPs 2 and 7 have been approved for clinical use because their osteoinductive properties act as an adjunctive treatment to surgeries where bone healing is compromised. BMP-9 is one of the least studied BMPs, and recent in vitro and in vivo studies have identified BMP-9 as a potent inducer of osteogenic differentiation in MSCs. BMP-9 exhibits significant molecular cross-talk with the Wnt/ β-catenin and other signaling pathways, and adenoviral expression of BMP-9 in MSCs increases the expression of osteogenic markers and induces trabecular bone and osteiod matrix formation. Furthermore, BMP-9 has been shown to act synergistically in bone formation with other signaling pathways, including Wnt/ β-catenin, IGF, and retinoid signaling pathways. These results suggest that BMP-9 should be explored as an effective bone regeneration agent, especially in combination with adjuvant therapies, for clinical applications such as large segmental bony defects, non-union fractures, and/or spinal fusions.
1 January 2020 in Evidence-Based Complementary and Alternative Medicine
Osteosarcoma (OS) is the most common primary malignant bone cancer. An increasing number of studies have demonstrated that ginsenoside Rg3 (Rg3), which is extracted from the roots of the traditional Chinese herb Panax ginseng, plays a tumor suppression role in various malignant tumors. In the present study, we aimed at investigating the role of Rg3 in the proliferation, migration, and invasion of OS and at exploring the underlying mechanisms. Cell viability and proliferation were observed by MTT assay and crystal violet staining. The migration and invasion of cells were measured by wound‐healing assay and Transwell method. Signaling pathway screening was investigated using luciferase reporter gene assay. qRT‐PCR and western blot were performed to measure the expression of molecules involved in cell epithelial‐mesenchymal transition (EMT), and Wnt/β‐catenin pathway. Results suggested that Rg3 could not only inhibit proliferation but also hamper the migration and invasion of OS. qRT‐PCR and western blot demonstrated that a reduced level of MMP2/MMP7/MMP9 was induced after Rg3 treatment. In addition, the expression levels of proteins related to EMT and the Wnt/β‐catenin pathway were downregulated. In summary, our data revealed that Rg3 could inhibit the proliferation, migration, and invasion of OS cells. This effect of Rg3 might be mediated by downregulating MMP2, MMP7, and MMP9 expression and suppressing EMT as well as the Wnt/β‐catenin pathway. Thus, Rg3 might be a potential agent for the treatment of OS.
MicroRNA‑708‑5p (miR‑708‑5p) and epithelial‑to‑mesenchymal transition (EMT) have been widely identified to contribute to the pathogenesis and progression of multiple cancers. However, the connection between miR‑708‑5p and EMT has not been sufficiently clarified. Therefore, our research aimed to investigate the impact of miR‑708‑5p on EMT and the metastasis of osteosarcoma (OS). We first analyzed the differentially expressed microRNAs (DEmiRNAs) from the GSE70367 dataset. We found that the expression of miR‑708‑5p was lower in OS cells. Overexpression of miR‑708‑5p was able to impair the migration and invasion of OS cells. Moreover, miR‑708‑5p inhibited EMT of OS cells MG63 and SaOS‑2, wherein E‑cadherin was increased, and N‑cadherin, vimentin, and Snail were decreased. Semaphorin 4C (SEMA4C), mitogen‑activated protein kinase kinase kinase 3 (MAP3K3), and zinc finger E‑box‑binding homeobox 1 (ZEB1) were predicted as target genes of miR‑708‑5p by bioinformatics method. Only ZEB1, one of the EMT‑inducing transcription factors, was validated as the direct target gene of miR‑708‑5p in OS cells through dual‑luciferase reporter assay and Western blot analysis. Knockdown of ZEB1 was found to inhibit the metastasis of MG63 and SaOS‑2 cells, whereas ZEB1 overexpression promoted their metastasis. In summary, miR‑708‑5p impaired the metastasis and EMT of OS, which was found to be mediated by inhibition of ZEB1.
Antibiotic residues in breast milk can have an impact on the intestinal flora and health of babies. Amoxicillin, as one of the most used antibiotics, affects the abundance of some intestinal bacteria. In this study, we developed a convenient and rapid process that used a combination of colorimetric methods and artificial intelligence image preprocessing, and back propagation-artificial neural network (BP-ANN) analysis to detect amoxicillin in breast milk. The colorimetric method derived from the reaction of gold nanoparticles (AuNPs) was coupled to aptamers (ssDNA) with different concentrations of amoxicillin to produce different color results. The color image was captured by a portable image acquisition device, and image preprocessing was implemented in three steps: segmentation, filtering, and cropping. We decided on a range of detection from 0 µM to 3.9 µM based on the physiological concentration of amoxicillin in breast milk and the detection effect. The segmentation and filtering steps were conducted by Hough circle detection and Gaussian filtering, respectively. The segmented results were analyzed by linear regression and BP-ANN, and good linear correlations between the colorimetric image value and concentration of target amoxicillin were obtained. The R2 and MSE of the training set were 0.9551 and 0.0696, respectively, and those of the test set were 0.9276 and 0.1142, respectively. In prepared breast milk sample detection, the recoveries were 111.00%, 98.00%, and 100.20%, and RSDs were 6.42%, 4.27%, and 1.11%. The result suggests that the colorimetric process combined with artificial intelligence image preprocessing and BP-ANN provides an accurate, rapid, and convenient way to achieve the detection of amoxicillin in breast milk.
1 July 2021 in Journal of Pharmaceutical and Biomedical Analysis