RESUMEN
OBJECTIVES: Steroid-induced osteonecrosis of the femoral head (SONFH) is characterized by impaired osteogenesis in bone marrow mesenchymal stem cells (BMSCs). This study investigates the role of lysine-specific demethylase 5A (KDM5A) in SONFH to identify potential therapeutic targets. METHODS: Human BMSCs were isolated and characterized for cell surface markers and differentiation capacity. A SONFH cell model was established using dexamethasone treatment. BMSCs were transfected with KDM5A overexpression vectors or si-KDM5A, and the expression of KDM5A, miR-107, runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and osteopontin (OPN) was assessed. Alizarin red staining was used to observe mineralization nodules, while alkaline phosphatase activity and cell viability were measured. The enrichment of KDM5A and histone 3 lysine 4 trimethylation (H3K4me3) on the promoters of RUNX2, OCN, and OPN was analyzed. The binding between miR-107 and KDM5A 3'UTR was validated, and the combined effect of miR-107 overexpression and KDM5A overexpression on BMSC osteogenic differentiation was evaluated. RESULTS: KDM5A was upregulated in BMSCs from SONFH. Inhibition of KDM5A promoted osteogenic differentiation of BMSCs, associated with increased RUNX2, OCN, and OPN promoters. KDM5A bound to the promoters of RUNX2, OCN, and OPN, leading to reduced H3K4me3 levels and downregulation of their expression. Overexpression of miR-107 inhibited KDM5A and enhanced BMSC osteogenic differentiation. CONCLUSION: KDM5A negatively regulates BMSC osteogenic differentiation by modulating H3K4me3 levels on the promoters of key osteogenic genes. miR-107 overexpression counteracts the inhibitory effect of KDM5A on osteogenic differentiation. These findings highlight the potential of targeting the KDM5A/miR-107 axis for SONFH therapy.
Asunto(s)
Células Madre Mesenquimatosas , MicroARNs , Humanos , Histonas , Subunidad alfa 1 del Factor de Unión al Sitio Principal , Osteogénesis , Cabeza Femoral , Lisina , MicroARNs/genética , Proteína 2 de Unión a Retinoblastoma/genéticaRESUMEN
BACKGROUND: Spontaneous restoration of large bone defects remains a challenge under infections, tumors, and crushing conditions. Current stem cell-based therapies for treating bone defects need improvement, because the used stem cells are isolated by a traditional protocol, which is based on their properties of in-vitro plastic adherence and fibroblastic colony formation. The stem cells isolated by the traditional protocol belong to a multicellular type mixture, individual cells vary in proliferative and osteogenic potential. Thus, developing a protocol capable of isolating stem cell subset with higher purity is required and urgent. AIM: This study aimed to sort a subpopulation of stem cells from periosteum using flow cytometry (named as FC-PSCs), and evaluate the proliferative and osteogenic capacity of FC-PSCs in-vitro, and then establish a new stem cell-based therapies for treating bone defects by delivering the FC-PSCs within platelet-rich plasma (PRP). METHODS: Mouse periosteum was used to sort FC-PSCs using flow cytometry with CD45-TER119-TIE2-ITGAV+CD90 + 6C3-CD105- markers, or isolate periosteum-derived stem cells with the traditional protocol (TP-PSCs) as control. After evaluating the FC-PSCs proliferation and osteogenic differentiation in-vitro as well as the promotive efficacy of platelet-rich plasma (PRP) on FC-PSCs proliferation and osteogenic differentiation, the FC-PSCs were delivered into the femoral epiphysis bone defect site of a mouse model by platelet-rich plasma (PRP). At postoperative 14 or 28 days, these mice were euthanized for harvest the femur specimens for micro-CT, histological evaluation. RESULTS: In-vitro results determined that the FC-PSCs showed more capacity for proliferation and osteogenic differentiation compared with the TP-PSCs. In addition, in-vitro results showed the promotive efficacy of PRP on FC-PSCs proliferation and osteogenic differentiation. In-vivo results showed that the FC-PSCs delivered by PRP was able to facilitate the repair of bone defects by stimulating new bone formation and remodeling. CONCLUSION: FC-PSCs delivered by PRP enhance the repair of bone defects by stimulating new bone formation and remodeling.
Asunto(s)
Células Madre Mesenquimatosas , Plasma Rico en Plaquetas , Ratones , Animales , Osteogénesis , Regeneración Ósea , Periostio , Proliferación Celular , Células Madre , Diferenciación CelularRESUMEN
The mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase that belongs to the phosphoinositide-3-kinase (PI3K)-related kinase family. Oncogenic activation of mTOR signaling significantly contributes to the progression of different types of cancers including osteosarcoma (OS; the most common primary malignant tumor of bone). In the present study, we review the association of the mTOR signaling pathway with OS, and the possible effective treatment strategies by targeting this pathway. In the metastatic behavior of OS, one of the most common actionable aberrations was found in the PI3K/Akt/mTOR pathway. Upon phosphorylation, activated mTOR contributes to OS cellular transformation and poor cancer prognosis via downstream effectors such as S6K1, 4EBP1 and eIF4E, which are overexpressed in OS. Targeting the mTOR complex is a significant approach in cancer therapeutic research, and of course, rapamycin is the primary inhibitor of mTOR. Various other chemotherapeutic molecules have also shown potential activity against mTOR. As mTOR is a new promising oncological target and blockade of the mTOR pathway with selective inhibitors has significant potential in OS therapeutic research, the development of the optimal dose, regimen and a rationale for the use of mTOR inhibitors in combination with other anticancer agents may provide a successful treatment strategy for OS.