Overcoming Monocarboxylate Transporter 8 (MCT8)-Deficiency to Promote Human Oligodendrocyte Differentiation and Myelination

• Main Authors: Jae Young Lee, Min Joung Kim, Devy Deliyanti, Michael F. Azari, Fernando Rossello, Adam Costin, Georg Ramm, Edouard G. Stanley, Andrew G. Elefanty, Jennifer L. Wilkinson-Berka, Steven Petratos
• Format: Article
• Language: English
• Published: Elsevier 2017-11-01
• Series: EBioMedicine
• Subjects: NKX2.1; Human embryonic stem cells; Monocarboxylate transporter 8; Allan-Herndon-Dudley syndrome; Thyroid hormone; Di-iodothyropropionic acid (DITPA); Oligodendrocytes
• Online Access: http://www.sciencedirect.com/science/article/pii/S2352396417304140

Cell membrane thyroid hormone (TH) transport can be facilitated by the monocarboxylate transporter 8 (MCT8), encoded by the solute carrier family 16 member 2 (SLC16A2) gene. Human mutations of the gene, SLC16A2, result in the X-linked-inherited psychomotor retardation and hypomyelination disorder, Allan-Herndon-Dudley syndrome (AHDS). We posited that abrogating MCT8-dependent TH transport limits oligodendrogenesis and myelination. We show that human oligodendrocytes (OL), derived from the NKX2.1-GFP human embryonic stem cell (hESC) reporter line, express MCT8. Moreover, treatment of these cultures with DITPA (an MCT8-independent TH analog), up-regulates OL differentiation transcription factors and myelin gene expression. DITPA promotes hESC-derived OL myelination of retinal ganglion axons in co-culture. Pharmacological and genetic blockade of MCT8 induces significant OL apoptosis, impairing myelination. DITPA treatment limits OL apoptosis mediated by SLC16A2 down-regulation primarily signaling through AKT phosphorylation, driving myelination. Our results highlight the potential role of MCT8 in TH transport for human OL development and may implicate DITPA as a promising treatment for developmentally-regulated myelination in AHDS.