Publications by authors named "Yasmine Kamen"

Oligodendrocytes are generated throughout life and in neurodegenerative conditions from brain resident oligodendrocyte precursor cells (OPCs). The transition from OPC to oligodendrocyte involves a complex cascade of molecular and morphological states that position the cell to make a fate decision to integrate as a myelinating oligodendrocyte or die through apoptosis. Oligodendrocyte maturation impacts the cell death mechanisms that occur in degenerative conditions, but it is unclear if and how the cell death machinery changes as OPCs transition into oligodendrocytes.

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Oligodendrocyte precursor cells (OPCs) generate myelinating oligodendrocytes and are the main proliferative cells in the adult central nervous system. OPCs are a heterogeneous population, with proliferation and differentiation capacity varying with brain region and age. We demonstrate that during early postnatal maturation, cortical, but not callosal, OPCs begin to show altered passive bioelectrical properties, particularly increased inward potassium (K) conductance, which correlates with G1 cell cycle stage and affects their proliferation potential.

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Myelinating oligodendrocytes die in human disease and early in aging. Despite this, the mechanisms that underly oligodendrocyte death are not resolved and it is also not clear whether these mechanisms change as oligodendrocyte lineage cells are undergoing differentiation and maturation. Here, we used a combination of intravital imaging, single-cell ablation, and cuprizone-mediated demyelination, in both female and male mice, to discover that oligodendrocyte maturation dictates the dynamics and mechanisms of cell death.

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In the central nervous system, oligodendrocyte precursor cells (OPCs) proliferate and differentiate into myelinating oligodendrocytes throughout life, allowing for ongoing myelination and myelin repair. With age, differentiation efficacy decreases and myelin repair fails; therefore, recent therapeutic efforts have focused on enhancing differentiation. Many cues are thought to regulate OPC differentiation, including neuronal activity, which OPCs can sense and respond to via their voltage-gated ion channels and glutamate receptors.

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Single-cell electrophysiological recordings combined with dye loading and immunohistochemistry provide unparalleled single-cell resolution of cell physiology, morphology, location, and protein expression. When correlated with bulk RNA sequencing, these data can define cell identity and function. Here, we describe a protocol to prepare acute brain slices from embryonic and postnatal mice for whole-cell patch clamp, dye loading and post-hoc immunohistochemistry, and cell isolation for bulk RNA sequencing.

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Oligodendrocyte precursor cells (OPCs) give rise to oligodendrocytes which myelinate axons in the central nervous system. Although classically thought to be a homogeneous population, OPCs are reported to have different developmental origins and display regional and temporal diversity in their transcriptome, response to growth factors, and physiological properties. Similarly, evidence is accumulating that myelinating oligodendrocytes display transcriptional heterogeneity.

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Plasticity in the central nervous system (CNS) allows for responses to changing environmental signals. While the majority of studies on brain plasticity focus on neuronal synapses, myelin plasticity has now begun to emerge as a potential modulator of neuronal networks. Oligodendrocytes (OLs) produce myelin, which provides fast signal transmission, allows for synchronization of neuronal inputs, and helps to maintain neuronal function.

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Brain tissue undergoes substantial activity-dependent reorganisation after stroke due to neuronal plasticity, leading to partial functional recovery in patients. Concurrent myelin repair is crucial for proper neuronal network function and reorganisation. Myelin repair after stroke might occur as myelin plasticity or as remyelination through the recruitment and differentiation of oligodendrocyte precursor cells (OPCs), which become myelin-forming oligodendrocytes (OLs).

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Oligodendrocyte precursor cells (OPCs) differentiate during postnatal development into myelin-forming oligodendrocytes, in a process distinguished by substantial changes in morphology and the onset of myelin gene expression. A mammalian-specific CNS myelin gene, tmem10, also called Opalin, encodes a type 1 transmembrane protein that is highly upregulated during early stages of OPC differentiation; however, a function for TMEM10 has not yet been identified. Here, consistent with previous studies, we detect TMEM10 protein in mouse brain beginning at ~P10 and show that protein levels continue to increase as oligodendrocytes differentiate and myelinate axons in vivo.

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Oligodendrocyte progenitor cells (OPCs), which differentiate into myelinating oligodendrocytes during CNS development, are the main proliferative cells in the adult brain. OPCs are conventionally considered a homogeneous population, particularly with respect to their electrophysiological properties, but this has been debated. We show, by using single-cell electrophysiological recordings, that OPCs start out as a homogeneous population but become functionally heterogeneous, varying both within and between brain regions and with age.

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