Myt1L Promotes Differentiation of Oligodendrocyte Precursor Cells and is Necessary for Remyelination After Lysolecithin-Induced Demyelination

The differentiation and maturation of oligodendrocyte precursor cells(OPCs) is essential for myelination and remyelination in the CNS. The failure of OPCs to achieve terminal differentiation in demyelinating lesions often results in unsuccessful remyelination in a variety of human demyelinating diseases. However, the molecular mechanisms controlling OPC differentiation under pathological conditions remain largely unknown. Myt1 L(myelin transcription factor 1-like), mainly expressed in neurons,has been associated with intellectual disability, schizophrenia, and depression. In the present study, we found that Myt1 L was expressed in oligodendrocyte lineage cells during myelination and remyelination. The expression level of Myt1 L in neuron/glia antigen 2-positive(NG2+)OPCs was significantly higher than that in mature CC1+oligodendrocytes. In primary cultured OPCs,overexpression of Myt1 L promoted, while knockdown inhibited OPC differentiation. Moreover, Myt1 L was potently involved in promoting remyelination after lysolecithin-induced demyelination in vivo. Ch IP assays showed that Myt1 L bound to the promoter of Olig1 and transcriptionally regulated Olig1 expression. Taken together, our findings demonstrate that Myt1 L is an essential regulator of OPC differentiation, thereby supporting Myt1 L as a potential therapeutic target for demyelinating diseases.

Shikimic Acid Promotes Oligodendrocyte Precursor Cell Differentiation and Accelerates Remyelination in Mice

The obstacle to successful remyelination in demyelinating diseases, such as multiple sclerosis, mainly lies in the inability of oligodendrocyte precursor cells(OPCs) to differentiate, since OPCs and oligodendrocytelineage cells that are unable to fully differentiate are found in the areas of demyelination. Thus, promoting the differentiation of OPCs is vital for the treatment of demyelinating diseases. Shikimic acid(SA) is mainly derived from star anise, and is reported to have antiinfluenza, anti-oxidation, and anti-tumor effects. In the present study, we found that SA significantly promoted the differentiation of cultured rat OPCs without affecting their proliferation and apoptosis. In mice, SA exerted therapeutic effects on experimental autoimmune encephalomyelitis(EAE), such as alleviating clinical EAE scores, inhibiting inflammation, and reducing demyelination in the CNS. SA also promoted the differentiation of OPCs as well as their remyelination after lysolecithin-induced demyelination.Furthermore, we showed that the promotion effect of SA on OPC differentiation was associated with the up-regulation of phosphorylated m TOR. Taken together, our resultsdemonstrated that SA could act as a potential drug candidate for the treatment of demyelinating diseases.

Cyclin-dependent Kinase 18 Promotes Oligodendrocyte Precursor Cell Differentiation through Activating the Extracellular Signal-Regulated Kinase Signaling Pathway

The correct differentiation of oligodendrocyte precursor cells(OPCs) is essential for the myelination and remyelination processes in the central nervous system.Determining the regulatory mechanism is fundamental to the treatment of demyelinating diseases. By analyzing the RNA sequencing data of different neural cells, we found that cyclin-dependent kinase 18(CDK18) is exclusively expressed in oligodendrocytes. In vivo studies showed that the expression level of CDK18 gradually increased along with myelin formation during development and in the remyelination phase in a lysophosphatidylcholine-induced demyelination model, and was distinctively highly expressed in oligodendrocytes. In vitro overexpression and interference experiments revealed that CDK18 directly promotes the differentiation of OPCs, without affecting their proliferation or apoptosis. Mechanistically, CDK18 activated the RAS/mitogen-activated protein kinase kinase1/extracellular signal-regulated kinase pathway, thus promoting OPC differentiation. The results of the present study suggest that CDK18 is a promising cell-type specific target to treat demyelinating disease.

Pinocembrin Promotes OPC Differentiation and Remyelination via the mTOR Signaling Pathway

The exacerbation of progressive multiple sclerosis(MS)is closely associated with obstruction of the differentiation of oligodendrocyte progenitor cells(OPCs).To discover novel therapeutic compounds for enhancing remyelination by endogenous OPCs,we screened for myelin basic protein expression using cultured rat OPCs and a library of small-molecule compounds.One of the most effective drugs was pinocembrin,which remarkably promoted OPC differentiation and maturation without affecting cell proliferation and survival.Based on these in vitro effects,we further assessed the therapeutic effects of pinocembrin in animal models of demyelinating diseases.We demonstrated that pinocembrin significantly ameliorated the progression of experimental autoimmune encephalomyelitis(EAE)and enhanced the repair of demyelination in lysolectin-induced lesions.Further studies indicated that pinocembrin increased the phosphorylation level of mammalian target of rapamycin(mTOR).Taken together,our results demonstrated that pinocembrin promotes OPC differentiation and remyelination through the phosphorylated mTOR pathway,and suggest a novel therapeutic prospect for this natural flavonoid product in treating demyelinating diseases.

MiR-30a Positively Regulates the Inflammatory Response of Microglia in Experimental Autoimmune Encephalomyelitis

Multiple sclerosis（MS） is a classical inflammatory demyelinating disease of the central nervous system（CNS）. Microglia are the main resident immune cells in the CNS and are closely associated with the pathogenesis of MS.In the present study, we found that mi R-30 a was highly expressed in jellyfish-like microglia in chronic active lesions of MS patients, as well as in the microglia of mice with experimental autoimmune encephalomyelitis（EAE） at the chronic phase. In vitro, the conditioned supernatant of mouse microglia overexpressing miR-30 a promoted the apoptosis of oligodendrocyte precursor cells（OPCs）, and inhibited OPC differentiation. In vivo, overexpressing miR-30 a in transplanted microglia exacerbated the progression of EAE.Overexpression and knock-down experiments in primary cultured mouse microglia showed that mi R-30 a increased the expression of IL-1 b and i NOS, which are pro-inflammatory, while inhibiting the expression of Ym-1 and CD206.Mechanistically, mi R-30 a inhibited the expression of Ppargc1 b, which is the co-activator of peroxisome proliferator-activated receptor gamma, resulting in pro-inflammatory effects. Our work shows that mi R-30 a is an important regulator of the inflammatory response in microglia, and may be a promising therapeutic target for inflammatory diseases like MS in the CNS.