Repression of developmental transcription factor networks triggers aging-associated gene expression in human glial progenitor cells.

Human glial progenitor cells (hGPCs) exhibit diminished expansion competence with age, as well as after recurrent demyelination. Using RNA-sequencing to compare the gene expression of fetal and adult hGPCs, we identify age-related changes in transcription consistent with the repression of genes enabling mitotic expansion, concurrent with the onset of aging-associated transcriptional programs. Adult hGPCs develop a repressive transcription factor network centered on MYC, and regulated by ZNF274, MAX, IKZF3, and E2F6. Individual over-expression of these factors in iPSC-derived hGPCs lead to a loss of proliferative gene expression and an induction of mitotic senescence, replicating the transcriptional changes incurred during glial aging. miRNA profiling identifies the appearance of an adult-selective miRNA signature, imposing further constraints on the expansion competence of aged GPCs. hGPC aging is thus associated with acquisition of a MYC-repressive environment, suggesting that suppression of these repressors of glial expansion may permit the rejuvenation of aged hGPCs.

How to make an oligodendrocyte.

Oligodendrocytes produce myelin, an insulating sheath required for the saltatory conduction of electrical impulses along axons. Oligodendrocyte loss results in demyelination, which leads to impaired neurological function in a broad array of diseases ranging from pediatric leukodystrophies and cerebral palsy, to multiple sclerosis and white matter stroke. Accordingly, replacing lost oligodendrocytes, whether by transplanting oligodendrocyte progenitor cells (OPCs) or by mobilizing endogenous progenitors, holds great promise as a therapeutic strategy for the diseases of central white matter. In this Primer, we describe the molecular events regulating oligodendrocyte development and how our understanding of this process has led to the establishment of methods for producing OPCs and oligodendrocytes from embryonic stem cells and induced pluripotent stem cells, as well as directly from somatic cells. In addition, we will discuss the safety of engrafted stem cell-derived OPCs, as well as approaches by which to modulate their differentiation and myelinogenesis in vivo following transplantation.

Pyridoxine administration improves behavioral and anatomical outcome after unilateral contusion injury in the rat.

The purpose of this project was to evaluate the preclinical efficacy of pyridoxine, or vitamin B(6). Rats received a 3.0 mm unilateral controlled cortical impact (CCI) injury of the sensorimotor cortex or sham surgery. Treatment with vitamin B(6) (600 or 300 mg/kg IP) or vehicle was administered at 30 min and 24 h post-CCI. Somatosensory dysfunction was evaluated with the vibrissae-forelimb placing and bilateral tactile adhesive removal tests. Sensorimotor dysfunction was evaluated with the locomotor placing and the forelimb asymmetry tests. On the forelimb asymmetry test both treatment groups displayed no asymmetry bias on any of the testing days post-CCI and were statistically no different than the shams. Both vitamin B(6) groups displayed a significant improvement in behavioral performance on the locomotor placing test compared to the vehicle-treated group. Administration of 600 mg/kg also significantly reduced tactile adhesive removal latencies on days 2, 4, 6, and 12 post-CCI. Both treatment groups were improved in their rate of recovery post-CCI on the vibrissae-forelimb placing test, but only the recovery seen in the 600-mg/kg group was significantly improved compared to vehicle. Finally, the 600-mg/kg dose resulted in significant cortical sparing compared to the vehicle-treated group. In general, the effects of vitamin B(6) on recovery of function were dose-dependent, with the 600-mg/kg dose consistently showing greater recovery than the 300-mg/kg dose. More experimental analyses are warranted to evaluate the potential preclinical efficacy and mechanistic action of vitamin B(6).