Emerging roles of long non-coding RNAs in osteonecrosis of the femoral head.

Osteonecrosis of the femoral head (ONFH) is a potentially disabling orthopedic condition that, in most late-stage cases, requires total hip arthroplasty. Although direct trauma to the hip (e.g. femoral neck fracture, hip dislocation) that leads to vascular interruption is a strong risk factor for ONFH, there are many non-traumatic risk factors (e.g. use of corticosteroid, alcohol abuse) which molecular mechanisms in ONFH still remain obscured. Long non-coding RNAs (lncRNAs) is a class of regulatory RNAs that play crucial roles in various cellular functions, including cell proliferation, invasion, metabolism, apoptosis and stem cell differentiation. Recent studies also suggested their participation in bone development and regeneration, and a direct involvement in the pathogenesis of numerous of orthopaedic conditions, such as ONFH. LncRNAs are differentially expressed in ONFH tissues as well as bone marrow-mesenchymal stem cells and bone microvascular endothelial cells isolated from ONFH patients. Functional studies further established their critical roles in regulating biological processes, such as osteoblast survival and osteogenic differentiation of bone marrow-mesenchymal stem cells, which are closely related to ONFH. The current review aims at summarizing the recent advancement in this field and discussing the potential diagnostic, prognostic and therapeutic utilities of lncRNAs in the clinical management of ONFH.