Biology subjects

Antel, J. P.

Publications and source records attributed to Antel, J. P..

13 recordsLinked to original sources

bioRxiv2026

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↗

bioRxiv2025

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↗

bioRxiv2025

Dendritic Polyglycerol Amine Substrate Extends the Viability of Mixed Glial Cultures for Repeated Isolation of Immature Oligodendrocyte Lineage Cells

Primary mixed glial cultures are key tools to isolate and study astrocytes, microglia and oligodendrocytes. Cell-substrate adhesion is critical for neural cell survival and differentiation. Cationic polymers like poly-D-lysine (PDL) are widely used to promote cell adhesion to cell culture substrates, however, PDL is not stable long-term, with cultured cells often detaching (peeling) after 2-3 weeks. Dendritic polyglycerol amine (dPGA) is a synthetic polycationic non-protein polymer biomimetic of poly-lysine that is highly resistant to degradation by cellular proteases. Substrates coated with dPGA promote cell adhesion and improve survival in long-term neuronal cultures. Here we assessed dPGA as a substrate coating to provide long-term support for mixed glial cultures. Oligodendrocyte precursor cells (OPCs) were isolated weekly by differential adhesion from cultures grown in T75 flasks with PDL or dPGA-coated substrates. Following two "shake-off" isolations, the cell layer in most PDL-coated flasks fully detached, rendering these flasks unusable for further culture. In contrast, dPGA-coated flasks consistently yielded cells for six or more sequential isolations over seven weeks in culture. dPGA-coated flasks produced more cells, a greater percentage of O4+ cells, and maintained similar proportions of OPCs and MBP-positive cells as when isolated from a PDL-coated substrate. dPGA is cyto-compatible, functionally superior, easy to use, low cost and a stable alternative to conventional cell substrate coatings. The enhanced long-term stability of mixed glial cultures grown on a dPGA substrate has the capacity to increase cellular yield, reduce animal use, and facilitate studies of oligodendrocyte cell biology.

neuroscience↗

bioRxiv2024

A subset of human choroid plexus epithelial cells exhibit mitochondrial eccentricity and distinct expression of the pigmentation-associated enzyme TYRP1

For decades, ultrastructural evaluation of epithelial cells in diverse organ systems has demonstrated the existence of two subtypes identified by stark differences in cytoplasmic electron density - so-called light and dark epithelial cells. Choroid plexus (CP) epithelial cells are key regulators of CSF homeostasis and are one of many specialized epithelial linings that exhibit this bimodal phenotype. Despite longstanding acknowledgement, it has been difficult to assess the potential significance of adult human light and dark CP epithelial cells due to a lack of characterization beyond electron microscopy (EM). We present the first transcriptomic analysis of adult human CP epithelial cells and denote the existence of four epithelial subpopulations, one of which is defined by elevated expression of TYRP1 - a melanocyte-associated tyrosine-related protein involved in cellular pigmentation and proliferation. TYRP1-high cells also downregulate genes related to cilia function (which is consistent with observations of dark cell identity in organoids) and upregulate genes associated with pathways related to cell cycling, stress, and iron regulation. Our data provide an explanation of the molecular underpinning of adult human light and dark cell identity and serve as a resource for investigations of epithelial heterogeneity in the CP and other organs where dark cells are found.

neuroscience↗

bioRxiv2024

The functional and pathogenic consequences of fibrinogen on human oligodendroglia

Fibrinogen is a blood-derived protein involved in coagulation, and can make its way into the central nervous system (CNS) following breakdown of the blood-brain barrier. This molecule has been implicated in multiple sclerosis (MS), a disease marked by inflammation and demyelination in the CNS, as well as other neurological disorders. However, the effect of this molecule has not been studied on human myelinating cells. This study examines how fibrinogen influences human oligodendrocyte (OL) lineage cells at various stages of development. Using induced pluripotent stem cell-derived (iPSC) OL precursors and human primary OLs, we examined the effects of fibrinogen on cell differentiation, viability and myelination-related function. Here we show that fibrinogen induces an aberrant differentiation of early lineage OLs, by inhibiting their maturation and inducing an astrocytic phenotype, as seen in previous studies. On mature OLs, fibrinogen was found to promote myelination capacity as shown by ensheathment assays as well as on the RNA level. These effects were associated with the activation of BMP signalling, both in early and mature OLs. Transcriptomic analysis of human MS brain tissue shows similar pro-myelination changes in a subset of OLs, suggesting in vivo relevance. These findings indicate that fibrinogen has a lineage-dependent effect, where it may be inhibitory earlier in the lineage while promoting OL function in later stages. Understanding this dual role will provide insight into remyelination failure in MS and highlights the importance of timing and target in future therapeutic strategies. Significance StatementIn multiple sclerosis (MS), the blood protein fibrinogen leaks into the brain and has been shown to interfere with myelin repair. This study demonstrates that fibrinogen has opposite effects on human oligodendrocyte-lineage cells depending on their stage of maturation. While it blocks the differentiation of early-stage cells, it enhances the functional capacity of mature oligodendrocytes. These findings help explain why remyelination may fail in MS and suggest that fibrinogen could both hinder and support repair, depending on the cell context. This dual role has important implications for developing stage-specific therapies for MS.

neuroscience↗

bioRxiv2023

The Use of a SOX10 Reporter Towards Ameliorating Oligodendrocyte Lineage Differentiation from Human Induced Pluripotent Stem Cells

Oligodendrocytes (OLs) are key players in the central nervous system, critical for the formation and maintenance of the myelin sheaths insulating axons, ensuring efficient neuronal communication. In the last decade, the use of human induced pluripotent stem cells (iPSCs) has become essential for recapitulating and understanding the differentiation and role of OLs in vitro. Current methods include overexpression of transcription factors for rapid OL generation, neglecting the complexity of OL lineage development. Alternatively, growth factor-based protocols offer physiological relevance but struggle with efficiency and cell heterogeneity. To address these issues, we created a novel SOX10-P2A-mOrange iPSC reporter line to track and purify oligodendrocyte precursor cells (OPCs). Using this reporter cell line, we analyzed an existing differentiation protocol and shed light on the origin of glial cell heterogeneity. Additionally, we have modified the differentiation protocol, towards enhancing reproducibility, efficiency, and terminal maturity. Our approach not only advances OL biology but holds promise to accelerate research and translational work with iPSC-derived OLs. Main PointsO_LIThe differentiation of iPSCs in Oligodendrocyte Precursor Cells (OPCs) and Oligodendrocytes (OLs) is a notoriously difficult technique and often displays variable efficiency and cellular heterogeneity. C_LIO_LIWe engineered a novel reporter line carrying the fluorescent protein mOrange under the control of the OL-specific transcription factor SOX10 to track, purify and characterize OLs. C_LIO_LIBy experimenting with diverse differentiation media, we improved the generation of SOX10-positive cells. Consequently, these cells exhibited increased consistency and effectiveness in evolving into myelinating OLs. C_LI

cell biology↗

bioRxiv2023

An adapted stem cell-derived microglia protocol for the study of microgliopathies and other neurological disorders

BackgroundAdult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a primary microgliopathy caused by pathogenic variants in the colony-stimulating factor 1 receptor (CSF1R) gene. Since CSF1R signaling is crucial for microglia development, survival and function, induced pluripotent stem cell-derived microglia (iMGL) represent an excellent tool in studying microglial defects caused by ALSP patient-specific CSF1R variants. MethodsSerial modifications to an existing iMGL protocol were made, including but not limited to changes in growth factor combination to drive microglial differentiation, until successful derivation of microglia-like cells from an ALSP patient carrying a c.2350G > A (p.V784M) CSF1R variant. Using healthy control lines, the quality of the new iMGL protocol was validated through cell yield assessment, measurement of microglia marker expression, transcriptomic comparison to primary microglia, and evaluation of inflammatory and phagocytic activities. Similarly, molecular and functional characterization of the ALSP patient-derived iMGL was carried out in comparison to healthy control iMGL. ResultsThe newly devised protocol allowed the generation of iMGL with enhanced transcriptomic similarity to primary human microglia and with higher phagocytic and inflammatory competence at [~]3-fold greater yield compared to the original protocol. Using this protocol, decreased CSF1R autophosphorylation and cell surface expression was observed in iMGL derived from the ALSP patient compared to those derived from healthy controls. Additionally, ALSP patient-derived iMGL presented a migratory defect accompanying a temporal reduction in purinergic receptor P2Y12 (P2RY12) expression. Finally, ALSP patient-derived cells showed surprisingly high phagocytic capacity, which was associated with higher lysosomal content. ConclusionsWe optimized a pre-existing iMGL protocol, generating a powerful tool to study microglial involvement in human neurological diseases. Using the optimized protocol, we have generated for the first time iMGL from an ALSP patient carrying a pathogenic CSF1R variant, with preliminary characterization pointing toward functional alterations in migratory and phagocytic activities.

neuroscience↗

bioRxiv2023

MerTK mediates the immunologically silent uptake of alpha-synuclein fibrils by human microglia

MerTK is a receptor tyrosine kinase that mediates the immunologically silent phagocytic uptake of diverse types of cellular debris. Highly expressed on the surface of microglial cell, MerTK is of importance in brain development, homeostasis, plasticity, and disease. Yet, involvement of this receptor in the clearance of protein aggregates that accumulate with aging and in neurodegenerative diseases has yet to be defined. The current study explored the function of MerTK in the microglial uptake of alpha-synuclein fibrils which play a causative role in the pathobiology of synucleinopathies. Using human primary and induced pluripotent stem cell-derived microglia, the MerTK- dependence of alpha-synuclein fibril internalization was investigated in vitro. Relevance of this pathway to synucleinopathies was assessed by analyzing MerTK expression in patient-derived cells and tissues. Pharmacological inhibition of MerTK and siRNA-mediated MERTK knockdown both caused a decreased rate of alpha-synuclein fibril internalization by human microglia. Consistent with the immunologically silent nature of MerTK-mediated phagocytosis, alpha-synuclein fibril internalization did not induce secretion of pro-inflammatory cytokines from microglia. In addition, burden analysis in two independent patient cohorts revealed a significant association between rare functionally deleterious MERTK variants and Parkinsons disease in one of the cohorts (p = 0.002). Accordingly, MERTK expression was significantly upregulated in nigral microglia from Parkinsons disease/Lewy body dementia patients compared to those from non-neurological control donors in a single-nuclei RNA-sequencing dataset (p = 5.08x10-21), and MerTK protein expression positively correlated with alpha-synuclein level in human cortex lysates (p = 0.0029). Taken together, our findings define a novel role for MerTK in mediating the uptake of alpha-synuclein aggregates by human microglia, with possible involvement in limiting alpha-synuclein spread in synucleinopathies such as Parkinsons disease.

cell biology↗

bioRxiv2022

Systematic comparison of culture media uncovers phenotypic shift of human microglia defined by reduced reliance to CSF1R signaling

Efforts to understand microglia function in health and diseases have been hindered by the lack of culture models that recapitulate in situ cellular properties. In recent years, the use of serum-free media with brain-derived growth factors (CSF1R ligands and TGF-{beta}1/2) have been favored for the maintenance of rodent microglia as they promote morphological features observed in situ. Here we study the functional and transcriptomic impacts of such media on human microglia. Media formulation had little impact on microglia transcriptome assessed by RNA sequencing which was sufficient to significantly alter microglia capacity to phagocytose myelin debris and to elicit an inflammatory response to lipopolysaccharide. When compared to immediately ex vivo microglia from the same donors, the addition of fetal bovine serum to culture media, but not growth factors, was found to aid in the maintenance of key signature genes including those involved in phagocytic processes. A phenotypic shift characterized by CSF1R downregulation in culture correlated with a lack of reliance on CSF1R signaling for survival. Consequently, no improvement in cell survival was observed following culture supplementation with CSF1R ligands. Our study provides better understanding of human microglia in culture, with observations that diverge from those previously made in rodent microglia. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=181 SRC="FIGDIR/small/500101v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@16ea011org.highwire.dtl.DTLVardef@1cef01dorg.highwire.dtl.DTLVardef@f621aborg.highwire.dtl.DTLVardef@11c9f97_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2020

The identity of human tissue-emigrant CD8+ T cells

Lymphocyte migration is essential for human adaptive immune surveillance. However, our current understanding of this process is rudimentary, because most human studies to date have been restricted to immunological analyses of blood and various tissues. To address this issue, we used an integrated approach to characterize tissue-emigrant immune cells in thoracic duct lymph (TDL). In humans and non-human primates, lymphocytes were by far the most abundant immune lineage population in efferent lymph, and a vast majority of these lymphocytes were T cells. Cytolytic CD8+ T cell subsets were clonotypically discrete and selectively confined to the intravascular circulation, persisting for months after inhibition of S1P-dependent tissue egress by FTY-720. In contrast, non-cytolytic CD8+ T cell subsets with stem-like epigenetic and transcriptional signatures predominated in tissues and TDL. Collectively, these data provide an atlas of the migratory immune system and define the nature of tissue-emigrant CD8+ T cells that recirculate via TDL.

immunology↗

bioRxiv2020

Multiple sclerosis iPSC-derived oligodendroglia conserve their intrinsic properties to functionally interact with axons and glia in vivo

The remyelination failure in multiple sclerosis (MS) is associated with a migration/differentiation block of oligodendroglia. The reason for this block is highly debated. It could result from disease-related extrinsic regulators of the oligodendroglial biology or reflect MS oligodendrocyte intrinsic properties. To avoid confounding immune-mediated extrinsic effect, we used an immune-deficient, dysmyelinating mouse model, to compare side-by-side induced pluripotent stem-cell-derived O4+ oligodendroglia from MS and healthy donors following their engraftment in the developing CNS. We show that the MS-progeny survives, proliferates and differentiates into oligodendrocytes to the same extent as controls. Quantitative multi-parametric imaging indicates that MS and control oligodendrocytes generate equal amounts of myelin, with bona-fide nodes of Ranvier and promote equal restoration of their host slow conduction. Moreover, the MS-derived progeny expressed oligodendrocyte- and astrocyte-specific connexins and established functional connections with donor and host glial cells. Thus, MS pluripotent stem cell-derived progeny fully integrates into functional axo-glial and glial-glial components, reinforcing the view that the MS oligodendrocyte differentiation block is not due to intrinsic oligodendroglial deficits. These biological findings as well as the fully integrated human-murine chimeric model should facilitate the development of pharmacological or cell-based therapies to promote CNS remyelination. One Sentence SummaryMultiple Sclerosis oligodendroglia, regardless of major immune manipulators, are intrinsically capable of myelination and making functional axo-glia and glia-glia connections after engraftment in the murine CNS, reinforcing the view that the MS oligodendrocyte differentiation block is not due to major intrinsic oligodendroglial deficits but most likely to environmental conditions.

neuroscience↗

bioRxiv2019

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↗

bioRxiv2018

Deep learning for high-throughput quantification of oligodendrocyte ensheathment: a UNet architecture to extract multiple morphological parameters from individual cells

AO_SCPLOWBSTRACTC_SCPLOWHigh-throughput quantification of oligodendrocyte (OL) myelination is a significant challenge that, if addressed, would facilitate the development of therapeutics to promote myelin protection and repair. Here, we established a quantitative high-throughput method to asses OL ensheathment in-vitro, combining nanofiber culture devices and automated imaging with a heuristic approach that informed the development of a deep learning analytic algorithm. The heuristic approach was developed by modeling general characteristics of OL ensheathments, while the deep learning neural network employed a UNet architecture with enhanced capacity to associate ensheathed segments with individual OLs. Reliably extracting multiple morphological parameters from individual cells, without heuristic approximations, mimics the high-level decision-making capacity of human researchers and improves the validity of the neural network. Experimental validation demonstrated that the deep learning approach matched the accuracy of expert-human measurements of the length and number of myelin segments per cell. The combined use of automated imaging and analysis reduces tedious manual labor while eliminating variability. The capacity of this technology to perform multi-parametric analyses at the level of individual cells permits the detection of nuanced cellular differences to accelerate the discovery of new insight into OL physiology.

bioinformatics↗