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Cui, Q.-L.

Publications and source records attributed to Cui, Q.-L..

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Remodeling oligodendrocyte lipid metabolism via liver X receptors overcomes inflammatory blockade of remyelination

Multiple sclerosis is characterized by immune-mediated demyelination and inefficient remyelination, owing to impaired differentiation of oligodendrocyte precursor cells (OPCs) into myelinating oligodendrocytes (OLs). Inflammatory cytokines within multiple sclerosis lesions inhibit OPC maturation and induce an immune-like phenotype with antigen-presenting properties, but the underlying mechanisms remain poorly defined. Here, we show that inflammation reprograms OPC lipid metabolism, linking altered metabolism to remyelination failure. In cultured rodent OPCs, interferon-{gamma} (IFN-{gamma}) induced a switch from lipid synthesis to utilization, leading to reduced intracellular fatty acid levels and increased dependence on fatty acid oxidation. Transcriptional analyses confirmed similar lipid metabolic changes in OL-lineage cells cultured from human surgical specimens or isolated from mouse models of inflammatory demyelination and human multiple sclerosis lesions. Enhancing lipid availability in OPCs through oleic acid supplementation or inhibition of fatty acid oxidation attenuated immune-like functions and increased differentiation. Pharmacologic activation of liver X receptor (LXR) transcription factors rebalanced lipid metabolism, suppressed immune-like functions, and overcame IFN-{gamma}-induced differentiation blockade in both mouse and human-derived OPCs. In an adoptive transfer-cuprizone mouse model in which inflammation directly impairs remyelination, LXR activation increased mature OL generation and augmented myelin repair. Together, these findings identify lipid metabolic remodeling as a key mechanism by which inflammation impairs OPC differentiation and highlight LXR activation as a therapeutic approach to enhance remyelination in multiple sclerosis.

neuroscience↗

Epigenomic regulation of human oligodendrocyte myelination properties, relation to age and lineage

Multiple sclerosis (MS) is characterized by immune-mediated injury to myelin and oligodendrocytes (OLs). Repair depends on the ability of OL lineage cells to form new myelin and ensheathe axons. We previously showed that late progenitors (O4+A2B5+ cells) and mature human OLs exhibit age-related differences in ensheathment capacity and vulnerability to injury. Here, we test the hypothesis that differences in chromatin accessibility and specific histone marks may underlie transcriptional differences linked to these functional responses. Confocal imaging of cultured cells revealed higher levels of the transcriptionally permissive histone marks H3K27ac and H4K8ac in pediatric than adult derived late progenitors and mature OLs. Levels were higher in adult-derived progenitors versus mature cells from the same individuals. The majority of pathways and genes related to myelination and immune interactions were downregulated in adult cell samples when compared to pediatric samples. Analysis of publicly available datasets indicated that the chromatin accessibility for genes within these categories was more restricted in adult than pediatric OLs. There was less chromatin accessibility and lower H3K27ac chromatin occupancy also in more differentiated OL compared to progenitors. The levels of the transcriptionally repressive H3K27me3 histone mark in mature OLs were enriched in genomic regions encoding for transcriptional inhibitors of myelination and related signaling pathways, as compared to early progenitors. Restrictions in chromatin accessibility were more pronounced in human cells than in mouse cells. These results link the myelination capacity and immune-mediated injury susceptibility of human OLs to their epigenomic state, raising the issue of how epigenetic modulation could influence disease progression. Significance StatementNeurological disability in multiple sclerosis reflects a balance between the extent of tissue injury and repair. Human oligodendrocytes display distinct donor age- and maturity stage-related epigenomic profiles, which may influence both their myelination potential and vulnerability to immune-mediated injury. Our results emphasize that epigenomic status, particularly chromatin accessibility and specific histone modifications (H3K27ac and H3K27me3), may underlie these functional capacities. Thus, therapeutic strategies aimed at epigenomic modulation must be carefully considered, due to their net effect on these competing processes--promoting myelin repair while potentially altering susceptibility to further damage--to achieve beneficial clinical outcomes.

neuroscience↗

Pro-Inflammatory Molecules Implicated in Multiple Sclerosis Divert the Development of Human Oligodendrocyte Lineage Cells

Background and ObjectivesOligodendrocytes (OL) and their myelin-forming processes are targeted and lost during the disease course of Multiple Sclerosis (MS), targeted by infiltrating leukocytes and their effector cytokines. Myelin repair is considered to be dependent on recruitment and differentiation of oligodendrocyte precursor cells (OPCs). The basis of failure of re-myelination during the disease course of MS remains to be defined. The aim of this study is to determine the impact of pro-inflammatory molecules tumor necrosis factor (TNF) and interferon gamma (IFN{gamma}) on the differentiation of human OPCs. MethodsWe generated human OPCs from induced pluripotent stem cells with a reporter gene under the OL-specific transcription factor SOX10. We treated the cells in vitro with TNF or IFN{gamma} and evaluated effects in terms of cell viability, expression of OL-lineage markers, and co- expression of astrocyte markers. To relate our findings to the molecular properties of OPCs as found in the MS brain we re-analyzed publicly available single nuclear RNAseq datasets. ResultsOur analysis indicated that both TNF and IFN{gamma} decreased the proportion of cells differentiating into the OL-lineage; consistent with previous reports. We now observe the TNF effect is linked to aberrant OPC differentiation. A subset of O4+, reporter-positive cells co- expressed the astrocytic marker Aquaporin-4 (AQP4). On the transcriptomic level, the cells acquire an astrocyte-like signature alongside a conserved reactive phenotype. Analysis of single- nuclear RNAseq datasets from human MS brain revealed a subset of OPCs expressing an astrocytic signature. DiscussionIn the context of MS, these results imply that OPCs are present but inhibited from differentiating along the OL-lineage, with a subset acquiring a reactive and stem-cell like phenotype, reducing their capacity to contribute towards repair. These findings help define a potential basis for the impaired myelin repair in MS and provide a prospective route for regenerative treatment.

neuroscience↗

RNA-binding protein altered expression and mislocalization in multiple sclerosis

ObjectiveNuclear depletion and mislocalization of RNA-binding proteins (RBPs) trans-activation response DNA-binding protein of 43 kDa (TDP-43) and fused in sarcoma (FUS) are thought to contribute to the pathogenesis of a number of disorders, including amyotrophic lateral sclerosis (ALS). We recently found that TDP-43 as well as polypyrimidine tract binding protein (PTB) have decreased expression and mislocalization in oligodendrocytes in demyelinated lesions in an experimental mouse model of multiple sclerosis (MS) caused by Theilers murine encephalomyelitis virus infection.\n\nMethodsThe latter finding prompted us to investigate TDP-43, FUS, and PTB in the demyelinated lesions of MS and in in vitro cultured human brain-derived oligodendrocytes.\n\nResultsWe found: i) mislocalized TDP-43 in oligodendrocytes in active lesions in some MS patients; ii) decreased PTB1 expression in oligodendrocytes in mixed active/inactive demyelinating lesions; iii) decreased nuclear expression of PTB2 in neurons in cortical demyelinating lesions; iv) nuclear depletion of TDP-43 in oligodendrocytes under metabolic stress induced by low glucose/low nutrient conditions compared to optimal culture conditions.\n\nConclusionTDP-43 has been found to have a key role in oligodendrocyte function and viability, while PTB is important in neuronal differentiation, suggesting that altered expression and mislocalization of these RBPs in MS lesions may contribute to the pathogenesis of demyelination and neurodegeneration. Our findings also identify nucleocytoplasmic transport as a target for treatment.

neuroscience↗