Reduced levels of Coco in sera of multiple sclerosis patients: A potential role in neuro-regeneration failure.

Demyelination, axonal loss and failure of tissue repair characterize MS lesions. Bone morphogenetic proteins (BMPs) signaling is associated with remyelination failure. Coco is one of the BMP antagonists. We found reduced Coco serum levels in relapsing-remitting MS (RR-MS) and primary progressive MS (PP-MS) patients compared to matched healthy controls (HC) and patients with rheumatoid arthritis. Exposure of P19 cells, in the presence of retinoic acid, BMP-2, or BMP-4 to Coco, at average sera level of MS patients failed to induce neuronal phenotype, in contrast to the average sera level of HC. Coco may be a player in the BMP dysregulation and the tissue repair failure in MS.

Progesterone effects on oligodendrocyte differentiation in injured spinal cord.

Spinal cord lesions result in chronic demyelination as a consequence of secondary injury. Although oligodendrocyte precursor cells proliferate the differentiation program fails. Successful differentiation implies progressive decrease of transcriptional inhibitors followed by upregulation of activators. Progesterone emerges as an anti-inflammatory and pro-myelinating agent which improves locomotor outcome after spinal cord injury. In this study, we have demonstrated that spinal cord injury enhanced oligodendrocyte precursor cell number and decreased mRNA expression of transcriptional inhibitors (Id2, Id4, hes5). However, mRNA expression of transcriptional activators (Olig2, Nkx2.2, Sox10 and Mash1) was down-regulated 3 days post injury. Interestingly, a differentiation factor such as progesterone increased transcriptional activator mRNA levels and the density of Olig2- expressing oligodendrocyte precursor cells. The differentiation program is regulated by extracellular signals which modify transcriptional factors and epigenetic players. As TGFß1 is a known oligodendrocyte differentiation factor which is regulated by progesterone in reproductive tissues, we assessed whether TGFß1 could mediate progesterone remyelinating actions after the lesion. Notwithstanding that astrocyte, oligodendrocyte precursor and microglial cell density increased after spinal cord injury, the number of these cells which expressed TGFß1 remained unchanged regarding sham operated rats. However, progesterone treatment increased TGFß1 mRNA expression and the number of astrocytes and microglial TGFß1 expressing cells which would indirectly enhance oligodendrocyte differentiation. Therefore, TGFß1 arises as a potential mediator of progesterone differentiating effects on oligodendrocyte linage.

Estabelecimento de metodologia de diferenciação de células tronco embrionárias de camundongo em células precursoras de oligodendrócitos: uma plataforma para triagem de novas drogas remielinizantes / Establishment of a mouse embryonic stem cell line differentiation methodology into oligodendrocyte precursor cells: a platform for remyelinating drug screening.

The myelin sheath plays a crucial role in nerve function. In the Central Nervous System, the myelin sheath is produced by oligodendrocytes (OL), which are differentiated from oligodendrocyte precursor cells (OPC). Several neurological disorders, including multiple sclerosis, display damage in the myelin sheath and failure in the remyelination. Therefore, researching for new compounds that act in the OPCs differentiation to OLs is a promising strategy to treat demyelinating diseases. In this study, we established a methodology that allows the generation of OPCs in large quantities from two lineages of mouse embryonic stem cells (mESCs; lineages HM-1 and USP-1). Initially, mESCs were induced to differentiate into neural precursors and, later, to OPCs by adding growth factors such as FGF, EGF and PDGF. The characteristic and predominant expression of Olig2, Sox-10, PDGFRα and NG2 observed by immunofluorescence, and the double labeling of PDGFRα and NG2 by flow cytometry, confirmed the OPCs generation from mESCs. Therefore, this study shows an efficient and reproducible methodology for generating OPCs capable of being used in screening assays or in OLs lineage biology studies.

A bainha de mielina desempenha um papel crucial nas funções nervosas. No sistema nervoso central, a bainha de mielina é produzida por oligodendrócitos (OLs), os quais são diferenciados a partir de células precursoras de oligodendrócitos (OPCs). Em várias desordens neurológicas, entre elas, a Esclerose Múltipla, a bainha de mielina é danificada e a remielinização deixa de acontecer. Desse modo, a busca por novos compostos que atuem na diferenciação de OPCs a OLs, é um caminho promissor na terapia de doenças desmielinizantes. Neste estudo, estabelecemos uma metodologia que permitiu gerar OPCs a partir de duas linhagens de células tronco embrionárias de camundongos (mESCs – linhagens USP-1 e HM-1). Inicialmente, as mESCs foram induzidas a diferenciar em precursores neurais e, posteriormente, a OPCs, pela adição de fatores de crescimento como FGFb, EGF e PDGF-AA. A expressão característica e predominante de Olig2, Sox10, PDGFRα e NG2 observada por imunofluorescência e a dupla marcação de PDGFRα e NG2 por citometria de fluxo (com rendimentos de 88,3-87,3%) confirmaram a obtenção de OPCs a partir de mESCs. Estas células podem ser expandidas por 5 passagens adicionais e ainda serem capazes de gerar bilhões de OPC puros. Portanto, o estudo apresenta uma metodologia eficiente e reprodutível que permite a geração de um modelo a ser empregado em triagem de novas drogas ou no estudo da biologia da linhagem de OLs.