The Journey of iPSC-derived OPCs in Demyelinating Disorders: From In vitro Generation to In vivo Transplantation.

Loss of myelination is common among neurological diseases. It causes significant disability, even death, if it is not treated instantly. Different mechanisms involve the pathophysiology of demyelinating diseases, such as genetic background, infectious, and autoimmune inflammation. Recently, regenerative medicine and stem cell therapy have shown to be promising for the treatment of demyelinating disorders. Stem cells, including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and adult stem cells (ASCs), can differentiate into oligodendrocyte progenitor cells (OPCs), which may convert to oligodendrocytes (OLs) and recover myelination. IPSCs provide an endless source for OPCs generation. However, the restricted capacity of proliferation, differentiation, migration, and myelination of iPSC-derived OPCs is a notable gap for future studies. In this article, we have first reviewed stem cell therapy in demyelinating diseases. Secondly, methods of different protocols have been discussed among in vitro and in vivo studies on iPSC-derived OPCs to contrast OPCs' transplantation efficacy. Lastly, we have reviewed the results of iPSCs-derived OLs production in each demyelination model.

The regulatory functions of circular RNAs in osteosarcoma.

Osteosarcoma (OS) is known as a malignant bone tumor affecting mainly children and younger adults. Despite all the improvements in the treatment of OS, the overall survival among patients remained mostly unsatisfied. It involves different mechanisms and signaling pathways. Some recent studies confirmed that circular RNAs (circRNAs) have a revelatory role in controlling OS cell proliferation, invasion, and metastasis. CircRNAs consist of a covalently closed-loop structure with neither 5' nor 3' poly adenylated tail, lacking protein-encoding ability formed by back-splicing mechanisms. They mainly act as microRNA (miRNA) sponges and modulate the downstream biological processes. Up/down regulation of some circRNAs demonstrated to serve as the oncogenic factor in some tumor tissues such as OS. In this article, we review the regulatory functions of circRNAs resulting in OS cell progression or restraint and the potential for being used in vitro or in vivo as diagnostic or therapeutic biomarkers.