Differentiation Of Oligodendrocyte Progenitor Cells Research Articles

Remyelination in neuromyelitis optica spectrum disorder is promoted by edaravone through mTORC1 signaling activation.

Neuromyelitis optica spectrum disorder (NMOSD) is a severe inflammatory autoimmune disease of the central nervous system that is manifested as secondary myelin loss. Oligodendrocyte progenitor cells (OPCs) are the principal source of myelinating oligodendrocytes (OLs) and are abundant in demyelinated regions of NMOSD patients, thus possibly representing a cellular target for pharmacological intervention. To explore the therapeutic compounds that enhance myelination due to endogenous OPCs, we screened the candidate drugs in mouse neural progenitor cell (NPC)-derived OPCs. We identified drug edaravone, which is approved by the Food and Drug Administration (FDA), as a promoter of OPC differentiation into mature OLs. Edaravone enhanced remyelination in organotypic slice cultures and in mice, even when edaravone was administered following NMO-IgG-induced demyelination, and ameliorated motor impairment in a systemic mouse model of NMOSD. The results of mechanistic studies in NMO-IgG-treated mice and the biopsy samples of the brain tissues of NMOSD patients indicated that the mTORC1 signaling pathway was significantly inhibited, and edaravone promoted OPC maturation and remyelination by activating mTORC1 signaling. Furthermore, pharmacological activation of mTORC1 signaling significantly enhanced myelin regeneration in NMOSD. Thus, edaravone is a potential therapeutic agent that promotes lesion repair in NMOSD patients by enhancing OPC maturation.

The role of depolarizing activation of Na+-Ca2+ exchanger by oligodendrocyte progenitor cells in the effect of sevoflurane on myelination

AimsThe aim of this study was to investigate the role of depolarizing activation of Na+-Ca2+ exchanger (NCX) by oligodendrocyte progenitor cells (OPC) in the effect of sevoflurane on myelination. Main methodsOn postnatal days 7, 8, and 9, mice were exposed to 3 % sevoflurane for 2 h per day. The proliferation, differentiation, and myelin sheath of OPC were observed with immunofluorescence, quantitative real-time polymerase chain reaction (QRT-PCR), and transmission electron microscopy (TEM) at various time points. The open field, Y maze, and new object recognition tests were used to measure spatial learning and memory. siRNA was used for the knockdown NCX1 in human OPC (HOPC) before sevoflurane exposure; the Transwell migration assay was used to measure cell migration ability and Fluo 4-AM was used to measure intracellular Ca2+ concentration. Key findingsPretreatment with an NCX inhibitor attenuated the proliferation and differentiation of OPC induced by sevoflurane and induced a remarkable increase in platelet-derived growth factor receptor-alpha (PDGFRα), 2, 3-cyclic nucleotide 3-phosphodiesterase (CNPase), oligodendrocyte transcription factor 2 (Olig2), and homeodomain protein NK2 homeobox 2 (NKX2.2) levels. Pretreatment with an NCX inhibitor alleviated the sevoflurane-induced myelination disorder and cognitive impairment. The decreased cell migration and increased intracellular Ca2+ concentration observed in the siRNA-negative control group was reversed in the sevoflurane plus siRNA-NCX1 group. SignificanceThis study suggests that repeated sevoflurane exposure in newborn mice leads to depolarization of OPC, which leads to Ca2+ influx through NCX and affects OPC proliferation, migration, differentiation, and myelination, ultimately leading to cognitive impairment.

Abstract 5 Human Umbilical Cord Blood-Derived Cell Therapy Product, DUOC-01, Promotes Remyelination by Driving the Differentiation of Oligodendrocyte Progenitor Cells

IntroductionDUOC-01 is a macrophage-like cell therapy product manufactured by culturing banked human umbilical cord blood cells under GMP conditions. Currently, the safety of DUOC-01 is being tested as a bridging therapy in children with demyelinating leukodystrophies undergoing unrelated donor umbilical cord blood transplantation after myeloablative conditioning. DUOC-01 protects against loss of function in several preclinical models with demyelinating conditions of the central nervous system, making it an attractive therapy for patients with multiple sclerosis (MS) who experience destruction of myelin sheaths as pathology of their disease. The mechanism by which DUOC-01 promotes remyelination and if it directly influences oligodendrocyte lineage cells is untested.ObjectiveUsing multiple systems (primary oligodendrocyte precursor cell [OPC] cultures, in vitro cerebellar slice cultures, and experimental autoimmune encephalomyelitis [EAE], a mouse model of MS), we examined how DUOC-01 influences numerous steps of pathology and recovery.MethodsUsing a brain slice culture, we added DUOC-01 to the lysophosphatidylcholine (LPC)-treated slices. We quantified myelinated axons by assessing percent co-localization of myelin basic protein and neurofilament in the control, LPC, and LPC+DUOC-01 groups. To test the DUOC-01 effect in the EAE model, we immunized C57BL/6 mice with myelin oligodendrocyte glycoprotein peptide (MOG35-55) in complete Freund’s adjuvant. To match clinical protocols, we incubated DUOC-01 in Ringer’s lactate with hydrocortisone (HC) for 2 hours at room temperature. At the onset of EAE disease symptoms, we injected DUOC-01 into the cerebrospinal fluid by a single intra-cisterna magna injection, then recorded clinical scores daily for 2 weeks. To test if DUOC-01 could directly affect OPCs, we set up a primary OPC culture isolated from neonatal mice and added DUOC-01 treatment to the culture.ResultsIn the cerebellar slice model, we demonstrated a higher number of myelinated neuron fibers in the DUOC-treated group compared with the LPC-treated group. In the EAE model, compared with mice injected with Ringer’s or HC+Ringer’s, mice injected with DUOC-01 derived clinical benefit with lower clinical scores. In the primary OPC culture, the DUOC-01 treatment drove the maturation of OPC to become myelin producing oligodendrocytes.DiscussionOur data suggest that DUOC-01 could be beneficial in treating MS and other diverse neurological demyelinating conditions.

GABAB receptor agonist baclofen promotes central nervous system remyelination.

Promoting remyelination is considered as a potential neurorepair strategy to prevent/limit the development of permanent neurological disability in patients with multiple sclerosis (MS). To this end, a number of clinical trials are investigating the potential of existing drugs to enhance oligodendrocyte progenitor cell (OPC) differentiation, a process that fails in chronic MS lesions. We previously reported that oligodendroglia express GABAB receptors (GABAB Rs) both in vitro and in vivo, and that GABAB R-mediated signaling enhances OPC differentiation and myelin protein expression in vitro. Our goal here was to evaluate the pro-remyelinating potential of GABAB R agonist baclofen (Bac), a clinically approved drug to treat spasticity in patients with MS. We first demonstrated that Bac increases myelin protein production in lysolecithin (LPC)-treated cerebellar slices. Importantly, Bac administration to adult mice following induction of demyelination by LPC injection in the spinal cord resulted in enhanced OPC differentiation and remyelination. Thus, our results suggest that Bac repurposing should be considered as a potential therapeutic strategy to stimulate remyelination in patients with MS.

Total astragalosides promote oligodendrocyte precursor cell differentiation and enhance remyelination in cuprizone-induced mice through suppression of Wnt/β-catenin signaling pathway

Ethnopharmacological relevanceRadix Astragali is a traditional Chinese medicine with various pharmacological effects. Total astragalosides (TA), the main effective ingredients in Radix Astragali, exert properties including anti-oxidative stress, anti-neuroinflammation, and neuroprotection. We previously found that TA alleviated experimental autoimmune encephalomyelitis (EAE) progression, a widely used animal model of multiple sclerosis (MS). As a chronic demyelination disease, MS generally manifests myelin loss and fails to myelin regeneration. Regulation of oligodendrocyte progenitor cells (OPCs) differentiation and remyelination is the fundamental strategy for MS treatment. However, whether TA could directly promote OPCs differentiation and remyelination is still unknown. Aims of the studyThis study was aimed to investigate pro-differentiation and myelin regeneration effects of TA on OPCs and Cuprizone (CPZ)-induced demyelination mice, an animal model of MS, and to explore mechanism underlying from regulation of OPCs differentiation and maturation. Materials and methodsMice were orally given CPZ (400 mg/kg) daily for 4 weeks to induce myelin loss, and then treated with TA (25 and 50 mg/kg) daily for 1 week. Cell proliferation assay, Western blot, RT-PCR, immunocytochemistry and immunohistochemistry were performed to explore the mechanisms. The role of TA in oligodendrocyte differentiation and maturation was evaluated using MO3.13, a human oligodendrocytic hybrid cell line. ResultsTA was shown to mitigate behavioral impairment in CPZ-induced mice. It markedly ameliorated myelin loss and enhanced remyelination in the corpus callosum of mice, evidenced by increased expression of myelin basic protein (MBP) and the number of CC1+ newly generated oligodendrocytes (OLs). TA also enhanced the expression of MBP at both mRNA and protein levels in MO3.13 cells. In CPZ-induced mice and MO3.13 cells, TA remarkably promoted the activation of GSK3β, repressed the phosphorylation of β-catenin, reduced the expression of transcription factor 4 and inhibitor of DNA binding 2. The agonist of β-catenin, SKL2001, partially abolished the pro-differentiation effect of TA in MO3.13 cells. ConclusionsTaken together, we clarified that TA could effectively enhance the differentiation and maturation of OPCs and accelerate remyelination in CPZ-induced mice through inhibition of Wnt/β-catenin signaling pathway. This study provides new insight into the beneficial effect of TA in the treatment of MS.

New Insights into Prenatal NO2 Exposure and Behavioral Abnormalities in Male Offspring: Disturbed Serotonin Metabolism and Delayed Oligodendrocyte Development.

Epidemiological studies show that prenatal exposure to nitrogen dioxide (NO2) might cause behavioral abnormalities in childhood. However, toxicological mechanisms for such effects remain unclear, and it is still difficult to define adverse outcome pathways linking exposures to behavioral phenotypes. In this study, by exposing pregnant mice to NO2 (2.5 ppm, 5 h/day) throughout gestation, we provided the first experimental evidence that prenatal NO2 exposure did cause anxiety- and depression-like behaviors in weaning male offspring but not females. Specifically, the behavioral abnormalities were associated with abnormal myelination and the alterations attributed to the delayed oligodendrocyte (OL) development in the fetus and the early stage after birth. The expression of platelet-derived growth factor receptor α (Pdgfr-α) and Olig2 significantly decreased in the NO2 group at E13.5 and E15.5, and the expression of Olig2, adenomatous polyposis coli colon (Cc1), and myelin basic protein (Mbp) was reduced in offspring at PNDs 1, 7, and 21. We performed the targeted metabolomic analysis of neurotransmitters in the placenta and found that prenatal exposure to NO2 disturbed the metabolism of placental neurotransmitters. Serotonin (5-HT) was transferred from the placenta to the fetus at E10.5, and its accumulation in the fetal forebrain might affect oligodendrocyte progenitor cell (OPC) differentiation and OL maturation and eventually be involved in behavioral abnormalities. Our findings provide new insights into the association between prenatal NO2 exposure with anxiety- and depression-like behaviors in male offspring.

Clemastine Promotes Differentiation of Oligodendrocyte Progenitor Cells Through the Activation of ERK1/2 via Muscarinic Receptors After Spinal Cord Injury.

The recovery of spinal cord injury (SCI) is closely associated with the obstruction of oligodendrocyte progenitor cell (OPC) differentiation, which ultimately induces the inability to generate newly formed myelin. To address the concern, drug-based methods may be the most practical and feasible way, possibly applying to clinical therapies for patients with SCI. In our previous study, we found that clemastine treatment preserves myelin integrity, decreases the loss of axons, and improves functional recovery in the SCI model. Clemastine acts as an antagonist of the muscarinic acetylcholine receptor (muscarinic receptor, MR) identified from a string of anti-muscarinic drugs that can enhance oligodendrocyte differentiation and myelin wrapping. However, the effects of clemastine on OPC differentiation through MRs in SCI and the underlying mechanism remain unclear. To explore the possibility, a rat model of SCI was established. To investigate if clemastine could promote the differentiation of OPCs in SCI via MR, the expressions of OPC and mature OL were detected at 7 days post injury (dpi) or at 14 dpi. The significant effect of clemastine on encouraging OPC differentiation was revealed at 14 dpi rather than 7 dpi. Under pre-treatment with the MR agonist cevimeline, the positive role of clemastine on OPC differentiation was partially disrupted. Further studies indicated that clemastine increased the phosphorylation level of extracellular signal–regulated kinase 1/2 (p-ERK1/2) and the expressions of transcription factors, Myrf and Olig2. To determine the relationship among clemastine, ERK1/2 signaling, specified transcription factors, and OPC differentiation, the ERK1/2 signaling was disturbed by U0126. The inhibition of ERK1/2 in SCI rats treated with clemastine decreased the expressions of p-ERK 1/2, Myrf, Olig2, and mature OLs, suggesting that ERK1/2 is required for clemastine on promoting OPC differentiation and that specified transcription factors may be affected by the activity of ERK1/2. Moreover, the impact of clemastine on modulating the level of p-ERK 1/2 was restricted following cevimeline pre-injecting, which provides further evidence that the role of clemastine was mediated by MRs. Altogether, our data demonstrated that clemastine, mediated by MRs, promotes OPC differentiation under the enhancement of Myrf and Olig2 by activating ERK1/2 signaling and suggests a novel therapeutic prospect for SCI recovery.

Cannabinoids modulate proliferation, differentiation, and migration signaling pathways in oligodendrocytes.

Cannabinoid signaling, mainly via CB1 and CB2 receptors, plays an essential role in oligodendrocyte health and functions. However, the specific molecular signals associated with the activation or blockade of CB1 and CB2 receptors in this glial cell have yet to be elucidated. Mass spectrometry-based shotgunproteomics and in silico biology tools were used to determine which signaling pathways and molecular mechanisms are triggered in a human oligodendrocytic cell line (MO3.13) by several pharmacological stimuli: the phytocannabinoid cannabidiol (CBD); CB1 and CB2 agonists ACEA, HU308, and WIN55, 212-2; CB1 and CB2 antagonists AM251 and AM630; and endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG). The modulation of cannabinoid signaling in MO3.13 was found to affect pathways linked to cell proliferation, migration, and differentiation of oligodendrocyte progenitor cells. Additionally, we found that carbohydrate and lipid metabolism, as well as mitochondrial function, were modulated by these compounds. Comparing the proteome changes and upstream regulators among treatments, the highest overlap was between the CB1 and CB2 antagonists, followed by overlaps between AEA and 2-AG. Our study opens new windows of opportunities, suggesting that cannabinoid signaling in oligodendrocytes might be relevant in the context of demyelinating and neurodegenerative diseases.Proteomics data are available at ProteomeXchange (PXD031923).

Young CSF restores oligodendrogenesis and memory in aged mice via Fgf17.

Recent understanding of how the systemic environment shapes the brain throughout life has led to numerous intervention strategies to slow brain ageing1-3. Cerebrospinal fluid (CSF) makes up the immediate environment of brain cells, providing them with nourishing compounds4,5. We discovered that infusing young CSF directly into aged brains improves memory function. Unbiased transcriptome analysis of the hippocampus identified oligodendrocytes to be most responsive to this rejuvenated CSF environment. We further showed that young CSF boosts oligodendrocyte progenitor cell (OPC) proliferation and differentiation in the aged hippocampus and in primary OPC cultures. Using SLAMseq to metabolically label nascent mRNA, we identified serum response factor (SRF), a transcription factor that drives actin cytoskeleton rearrangement, as a mediator of OPC proliferation following exposure to young CSF. With age, SRF expression decreases in hippocampal OPCs, and the pathway is induced by acute injection with young CSF. We screened for potential SRF activators in CSF and found that fibroblast growth factor 17 (Fgf17) infusion is sufficient to induce OPC proliferation and long-term memory consolidation in aged mice while Fgf17 blockade impairs cognition in young mice. These findings demonstrate the rejuvenating power of young CSF and identify Fgf17 as a key target to restore oligodendrocyte function in the ageing brain.

The Cellular Senescence Factor Extracellular HMGB1 Directly Inhibits Oligodendrocyte Progenitor Cell Differentiation and Impairs CNS Remyelination.

HMGB1 is a highly conserved, ubiquitous protein in eukaryotic cells. HMGB1 is normally localized to the nucleus, where it acts as a chromatin associated non-histone binding protein. In contrast, extracellular HMGB1 is an alarmin released by stressed cells to act as a danger associated molecular pattern (DAMP). We have recently determined that progenitor cells from multiple sclerosis patients exhibit a cellular senescent phenotype and release extracellular HMGB1 which directly impaired the maturation of oligodendrocyte progenitor cells (OPCs) to myelinating oligodendrocytes (OLs). Herein, we report that administration of recombinant HMGB1 into the spinal cord at the time of lysolecithin administration resulted in arrest of OPC differentiation in vivo, and a profound impairment of remyelination. To define the receptor by which extracellular HMGB1 mediates its inhibitory influence on OPCs to impair OL differentiation, we tested selective inhibitors against the four primary receptors known to mediate the effects of HMGB1, the toll-like receptors (TLRs)-2, -4, -9 or the receptor for advanced glycation end-products (RAGE). We found that inhibition of neither TLR9 nor RAGE increased OL differentiation in the presence of HMGB1, while inhibition of TLR4 resulted in partial restoration of OL differentiation and inhibiting TLR2 fully restored differentiation of OLs in the presence of HMGB1. Analysis of transcriptomic data (RNAseq) from OPCs identified an overrepresentation of NFκB regulated genes in OPCs when in the presence of HMGB1. We found that application of HMGB1 to OPCs in culture resulted in a rapid and concentration dependent shift in NFκB nuclear translocation which was also attenuated with coincident TLR2 inhibition. These data provide new information on how extracellular HMGB1 directly affects the differentiation potential of OPCs. Recent and past evidence for elevated HMGB1 released from senescent progenitor cells within demyelinated lesions in the MS brain suggests that a greater understanding of how this molecule acts on OPCs may unfetter the endogenous remyelination potential in MS.

Emerging role of neuregulin-1beta1 in pathogenesis and progression of multiple sclerosis

Emerging role of neuregulin-1beta1 in pathogenesis and progression of multiple sclerosis

Oscillatory calcium release and sustained store-operated oscillatory calcium signaling prevents differentiation of human oligodendrocyte progenitor cells

Endogenous remyelination in demyelinating diseases such as multiple sclerosis is contingent upon the successful differentiation of oligodendrocyte progenitor cells (OPCs). Signaling via the Gαq-coupled muscarinic receptor (M1/3R) inhibits human OPC differentiation and impairs endogenous remyelination in experimental models. We hypothesized that calcium release following Gαq-coupled receptor (GqR) activation directly regulates human OPC (hOPC) cell fate. In this study, we show that specific GqR agonists activating muscarinic and metabotropic glutamate receptors induce characteristic oscillatory calcium release in hOPCs and that these agonists similarly block hOPC maturation in vitro. Both agonists induce calcium release from endoplasmic reticulum (ER) stores and store operated calcium entry (SOCE) likely via STIM/ORAI-based channels. siRNA mediated knockdown (KD) of obligate calcium sensors STIM1 and STIM2 decreased the magnitude of muscarinic agonist induced oscillatory calcium release and attenuated SOCE in hOPCs. In addition, STIM2 expression was necessary to maintain the frequency of calcium oscillations and STIM2 KD reduced spontaneous OPC differentiation. Furthermore, STIM2 siRNA prevented the effects of muscarinic agonist treatment on OPC differentiation suggesting that SOCE is necessary for the anti-differentiative action of muscarinic receptor-dependent signaling. Finally, using a gain-of-function approach with an optogenetic STIM lentivirus, we demonstrate that independent activation of SOCE was sufficient to significantly block hOPC differentiation and this occurred in a frequency dependent manner while increasing hOPC proliferation. These findings suggest that intracellular calcium oscillations directly regulate hOPC fate and that modulation of calcium oscillation frequency may overcome inhibitory Gαq-coupled signaling that impairs myelin repair.

Neuroprotective effect of liraglutide in an experimental mouse model of multiple sclerosis: role of AMPK/SIRT1 signaling and NLRP3 inflammasome

The heterogeneous nature of multiple sclerosis (MS) and the unavailability of treatments addressing its intricate network and reversing the disease state is yet an area that needs to be elucidated. Liraglutide, a glucagon-like peptide-1 analogue, recently exhibited intriguing potential neuroprotective effects. The currents study investigated its potential effect against mouse model of MS and the possible underlying mechanisms. Demyelination was induced in C57Bl/6 mice by cuprizone (400 mg/kg/day p.o.) for 5 weeks. Animals received either liraglutide (25 nmol/kg/day i.p.) or dorsomorphin, an AMPK inhibitor, (2.5 mg/Kg i.p.) 30 min before the liraglutide dose, for 4 weeks (starting from the second week). Liraglutide improved the behavioral profile in cuprizone-treated mice. Furthermore, it induced the re-myelination process through stimulating oligodendrocyte progenitor cells differentiation via Olig2 transcription activation, reflected by increased myelin basic protein and myelinated nerve fiber percentage. Liraglutide elevated the protein content of p-AMPK and SIRT1, in addition to the autophagy proteins Beclin-1 and LC3B. Liraglutide halted cellular damage as manifested by reduced HMGB1 protein and consequently TLR-4 downregulation, coupled with a decrease in NF-κB. Liraglutide also suppressed NLRP3 transcription. Dorsomorphin pre-administration indicated a possible interplay between AMPK/SIRT1 and NLRP3 inflammasome activation as it partially reversed liraglutide’s effects. Immunohistochemical examination of Iba+ microglia emphasized these findings. In conclusion, liraglutide exerts neuroprotection against cuprizone-induced demyelination via anti-inflammatory, autophagic flux activation, NLRP3 inflammasome suppression, and anti-apoptotic mechanisms, possibly mediated, at least in part, via AMPK/SIRT1, autophagy, TLR-4/ NF-κB/NLRP3 signaling.Graphical abstractThe potential mechanistic insight of Lira in alleviating Cup-induced neurotoxicity via: (1) AMPK/SIRT1 pathways activation resulting in the stimulation of brain autophagy flux (confirmed by lowering Beclin-1 and LC3-B protein expression). (2) Inhibition of NLRP3 inflammasome activation, as evidenced by reduced HMGB1, TLR-4, NF-κB and NLRP3 protein expression, alongside diminishing the activation of its downstream cascade as reflected by reduced levels of caspase-1 and IL-1β protein expression. (3) A possible modulating interplay between the previously mentioned two pathways.

Restoring nuclear entry of Sirtuin 2 in oligodendrocyte progenitor cells promotes remyelination during ageing

The age-dependent decline in remyelination potential of the central nervous system during ageing is associated with a declined differentiation capacity of oligodendrocyte progenitor cells (OPCs). The molecular players that can enhance OPC differentiation or rejuvenate OPCs are unclear. Here we show that, in mouse OPCs, nuclear entry of SIRT2 is impaired and NAD+ levels are reduced during ageing. When we supplement β-nicotinamide mononucleotide (β-NMN), an NAD+ precursor, nuclear entry of SIRT2 in OPCs, OPC differentiation, and remyelination were rescued in aged animals. We show that the effects on myelination are mediated via the NAD+-SIRT2-H3K18Ac-ID4 axis, and SIRT2 is required for rejuvenating OPCs. Our results show that SIRT2 and NAD+ levels rescue the aged OPC differentiation potential to levels comparable to young age, providing potential targets to enhance remyelination during ageing.

Cerebrospinal fluid of progressive multiple sclerosis patients reduces differentiation and immune functions of oligodendrocyte progenitor cells.

Oligodendrocyte progenitor cells (OPCs) are responsible for remyelination in the central nervous system (CNS) in health and disease. For patients with multiple sclerosis (MS), remyelination is not always successful, and the mechanisms differentiating successful from failed remyelination are not well‐known. Growing evidence suggests an immune role for OPCs, in addition to their regenerative role; however, it is not clear if this helps or hinders the regenerative process. We studied the effect of cerebrospinal fluid (CSF) from relapsing MS (rMS) and progressive MS (pMS) patients on primary OPC differentiation and immune gene expression and function. We observed that CSF from either rMS or pMS patients has a differential effect on the ability of mice OPCs to differentiate into mature oligodendrocytes and to express immune functions. CSF of pMS patients impaired differentiation into mature oligodendrocytes. In addition, it led to decreased major histocompatibility complex class (MHC)‐II expression, tumor necrosis factor (TNF)‐α secretion, nuclear factor kappa‐B (NFκB) activation, and less activation and proliferation of T cells. Our findings suggest that OPCs are not only responsible for remyelination, but they may also play an active role as innate immune cells in the CNS.

Impact of anti-PDGFRα antibody surface functionalization on LNC uptake by oligodendrocyte progenitor cells

Impairment of oligodendrocyte progenitor cell (OPC) differentiation into oligodendrocytes and chronic inflammation are key determinants of poor remyelination observed in diseases such as multiple sclerosis. For many pro-myelinating molecules, the therapeutic potential is hindered by poor solubility or limited access to the targeted cells. A promising approach to improve the delivery of those molecules to OPC is to encapsulate them in functionalized Lipid Nanocapsules (LNC). We aimed to develop the first OPC-targeting LNC, by grafting an anti-PDGFRα antibody on the surface of the LNC using several strategies and evaluating the interaction with PDGFRα via ELISA. We found that only site-selective click-chemistry grafting maintained anti-PDGFRα/PDGFRα association, which was confirmed in vitro on primary rat OPC. In conclusion, we demonstrated that it was possible to produce anti-PDGFRα functionalized LNC, we confirmed the antibody's ability to recognize its receptor after grafting and we optimized techniques to characterize antibody functionalized LNC.

A targeted extracellular vesicles loaded with montelukast in the treatment of demyelinating diseases

The main pathological characteristics of demyelinating diseases are central nervous system (CNS) myelin damage, and the differentiation of oligodendrocyte precursor cells is the therapeutic target of myelin repair. Previous studies have found that a large number of platelet-derived growth factor receptor α(PDGFRα) positive oligodendrocyte progenitor cells (OPCs) accumulate in the lesion area of myelin injury, and differentiation is blocked. However, the therapeutic effects of drugs currently used clinically on OPCs differentiation and myelin repair are limited. The main reason is that it is difficult to reach the effective concentration of the drug in the lesion area. Therefore, efficiently delivering into the CNS lesion area is of great significance for the treatment of MS. Natural exosomes have good biocompatibility and are ideal drug carriers. The delivery of drugs to lesion areas can be achieved by giving the exosomes armed targeting ligand. Therefore, in this study, combining exosomes with PDGFA helps them accumulate in OPCs in vitro and in vivo. Further, load montelukast into exosomes to achieve targeted therapy for cuprizone-induced demyelination animal model. The implementation of this research will help provide effective treatments for demyelinating diseases and lay a theoretical foundation for its application in the clinical treatment of different demyelinating diseases.

Lanthionine Ketimine Ethyl Ester Accelerates Remyelination in a Mouse Model of Multiple Sclerosis.

Although over 20 disease modifying therapies are approved to treat Multiple Sclerosis (MS), these do not increase remyelination of demyelinated axons or mitigate axon damage. Previous studies showed that lanthionine ketenamine ethyl ester (LKE) reduces clinical signs in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS and increased maturation of oligodendrocyte (OL) progenitor cells (OPCs) in vitro. In the current study, we used the cuprizone (CPZ) demyelination model of MS to test if LKE could increase remyelination. The corpus callosum (CC) and somatosensory cortex was examined by immunohistochemistry (IHC), electron microscopy and for mRNA expression changes in mice provided 5 weeks of CPZ diet followed by 2 weeks of normal diet in the presence of LKE or vehicle. A significant increase in the number of myelinated axons, and increased myelin thickness was observed in the CC of LKE-treated groups compared to vehicle-treated groups. LKE also increased myelin basic protein and proteolipid protein expression in the CC and cortex, and increased the number of mature OLs in the cortex. In contrast, LKE did not increase the percentage of proliferating OPCs suggesting effects on OPC survival and differentiation but not proliferation. The effects of LKE on OL maturation and remyelination were supported by similar changes in their relative mRNA levels. Interestingly, LKE did not have significant effects on GFAP or Iba1 immunostaining or mRNA levels. These findings suggest that remyelinating actions of LKE can potentially be formulated to induce remyelination in neurological diseases associated with demyelination including MS.

C1q inhibits differentiation of oligodendrocyte progenitor cells via Wnt/β-catenin signaling activation in a cuprizone-induced mouse model of multiple sclerosis

Multiple sclerosis (MS) is a chronic central nervous system demyelinating disease of autoimmune originate. Complement C1q, a complex glycoprotein, mediates a variety of immunoregulatory functions considered important in the prevention of autoimmunity. Although we found that the increased serum C1q level was highly associated with the Fazekas scores and T2 lesion volume of MS patients, the effect and mechanism of C1q on demyelination remains unclear. Cluster analysis and protein array results showed that serum Wnt receptors Frizzled-6 and LRP-6 levels in MS patients were both increased, we proposed that C1q may be involved in demyelination via Wnt signaling. The increased C1q protein levels in the serum and brain tissue were confirmed in a cuprizone (CPZ)-induced demyelination mice model. Moreover, CPZ treatment induced significant increase of LRP-6 and Frizzled-6 protein in mice corpus callosum. LRP-6 extra-cellular domain (LRP-6-ECD) level in the serum and cerebrospinal fluid (CSF) of CPZ mice also significantly increased. Knockdown of the subunit C1s of C1 not only substantially attenuated demyelination, promoted M2 microglia polarization and improved neurological function, but inhibited β-catenin expression and its nuclear translocation in oligodendrocyte progenitor cells (OPCs). In vitro, C1s silence reversed the increased level of LRP-6-ECD in the medium and β-catenin expression in OPCs induced by C1q treatment. Meanwhile, inhibition of C1s also markedly lowered the number of EDU positive OPCs, but enhanced the number of CNPase positive oligodendrocyte and the protein of MBP. The present study indicated that C1q was involved in demyelination in response to CPZ in mice by preventing OPC from differentiating into mature oligodendrocyte via Wnt/β-catenin signaling activation.

Id2 and Id4 are not the major negative regulators of oligodendrocyte differentiation during early central nervous system development.

Myelin sheathes ensure the rapid conduction of neural impulse and provide nutritional support for neurons. Myelin sheathes are formed by differentiated oligodendrocytes (OLs) in the central nervous system. During OL development, the differentiation of oligodendrocyte progenitor cells (OPCs) into mature OLs is controlled by both positive differentiation factors (drivers) and negative regulatory factors (brakes). Previous studies have suggested Id2 and Id4 as the key negative factors for OL differentiation. However, these conclusions were mainly based on in vitro studies and the reported OL phenotype in Id4 mutants appear to be mild. In this study, we systematically investigated the in vivo function of Id2 and Id4 genes in OL differentiation in their genetic mutants and in embryonic chicken spinal cord. Our results showed that disruption of Id4 has no effect on OL differentiation and maturation, whereas Id2 mutants and Id2/Id4 compound mutants display a mild and transient precocity of OL differentiation. In agreement with these loss-of-function studies, Id2, but not Id4, is weakly expressed in OPCs. Despite their minor roles in OL differentiation, forced expression of Id2 and Id4 in embryonic chicken spinal cords strongly inhibit the differentiation of OPCs. Taken together, our detailed functional and expressional studies strongly suggest that Id2 and Id4 are not the major in vivo repressors of OPC differentiation during animal development, shedding new light on the molecular regulation of early OL development.