Celastrol inhibits oligodendrocyte and neuron ferroptosis to promote spinal cord injury recovery.

BACKGROUND: Spinal cord injury (SCI) is a traumatic injury to the central nervous system and can cause lipid peroxidation in the spinal cord. Ferroptosis, an iron-dependent programmed cell death, plays a key role in the pathophysiology progression of SCI. Celastrol, a widely used antioxidant drug, has potential therapeutic value for nervous system. PURPOSE: To investigate whether celastrol can be a reliable candidate for ferroptosis inhibitor and the molecular mechanism of celastrol in repairing SCI by inhibiting ferroptosis. METHODS: First, a rat SCI model was constructed, and the recovery of motor function was observed after treatment with celastrol. The regulatory effect of celastrol on ferroptosis pathway Nrf2-xCT-GPX4 was detected by Western blot and immunofluorescence. Finally, the ferroptosis model of neurons and oligodendrocytes was constructed in vitro to further verify the mechanism of inhibiting ferroptosis by celastrol. RESULTS: Our results demonstrated that celastrol promoted the recovery of spinal cord tissue and motor function in SCI rats. Further in vitro and in vivo studies showed that celastrol significantly inhibited ferroptosis in neurons and oligodendrocytes and reduced the accumulation of ROS. Finally, we found that celastrol could inhibit ferroptosis by up-regulating the Nrf2-xCT-GPX4 axis to repair SCI. CONCLUSION: Celastrol effectively inhibits ferroptosis after SCI by upregulating the Nrf2-xCT-GPX4 axis, reducing the production of lipid ROS, protecting the survival of neurons and oligodendrocytes, and improving the functional recovery.

Oleoylethanolamide ameliorates motor dysfunction through PPARα-mediates oligodendrocyte differentiation and white matter integrity after ischemic stroke.

BACKGROUND AND AIM: Our previous study has revealed that OEA promotes motor function recovery in the chronic stage of ischemic stroke. However, the neuroprotective mechanism of OEA on motor function recovery after stroke still is unexplored. Therefore, the aim of this study was to explore the effects of OEA treatment on angiogenesis, neurogenesis, and white matter repair in the peri-infarct region after cerebral ischemia. EXPERIMENTAL PROCEDURE: The adult male rats were subjected to 2 h of middle cerebral artery occlusion. The rats were treated with 10 and 30 mg/kg OEA or vehicle daily starting from day 2 after ischemia induction until they were sacrificed. KEY RESULTS AND CONCLUSIONS: The results revealed that OEA increased cortical angiogenesis, neural progenitor cells (NPCs) proliferation, migration, and differentiation. OEA treatment enhanced the survival of newborn neurons and oligodendrogenesis, which eventually repaired the cortical neuronal injury and improved motor function after ischemic stroke. Meanwhile, OEA treatment promoted the differentiation of oligodendrocyte progenitor cells (OPCs) and oligodendrogenesis by activating the PPARα signaling pathway. Our results showed that OEA restores motor function by facilitating cortical angiogenesis, neurogenesis, and white matter repair in rats after ischemic stroke. Therefore, we demonstrate that OEA facilitates functional recovery after ischemic stroke and propose the hypothesis that the long-term application of OEA mitigates the disability after stroke.

Amburana cearensis seed extract stimulates astrocyte glutamate homeostatic mechanisms in hippocampal brain slices and protects oligodendrocytes against ischemia.

BACKGROUND: Stroke is a leading cause of death and disability worldwide. A major factor in brain damage following ischemia is excitotoxicity caused by elevated levels of the neurotransmitter glutamate. In the brain, glutamate homeostasis is a primary function of astrocytes. Amburana cearensis has long been used in folk medicine and seed extract obtained with dichloromethane (EDAC) have previously been shown to exhibit cytoprotective activity in vitro. The aim of the present study was to analyse the activity of EDAC in hippocampal brain slices. METHODS: We prepared a dichloromethane extract (EDAC) from A. cearensis seeds and characterized the chemical constituents by 1H and 13C-NMR. Hippocampal slices from P6-8 or P90 Wistar rats were used for cell viability assay or glutamate uptake test. Hippocampal slices from P10-12 transgenic mice SOX10-EGFP and GFAP-EGFP and immunofluorescence for GS, GLAST and GLT1 were used to study oligodendrocytes and astrocytes. RESULTS: Astrocytes play a critical role in glutamate homeostasis and we provide immunohistochemical evidence that in excitotoxicity EDAC increased expression of glutamate transporters and glutamine synthetase, which is essential for detoxifying glutamate. Next, we directly examined astrocytes using transgenic mice in which glial fibrillary acidic protein (GFAP) drives expression of enhanced green fluorescence protein (EGFP) and show that glutamate excitotoxicity caused a decrease in GFAP-EGFP and that EDAC protected against this loss. This was examined further in the oxygen-glucose deprivation (OGD) model of ischemia, where EDAC caused an increase in astrocytic process branching, resulting in an increase in GFAP-EGFP. Using SOX10-EGFP reporter mice, we show that the acute response of oligodendrocytes to OGD in hippocampal slices is a marked loss of their processes and EDAC protected oligodendrocytes against this damage. CONCLUSION: This study provides evidence that EDAC is cytoprotective against ischemia and glutamate excitotoxicity by modulating astrocyte responses and stimulating their glutamate homeostatic mechanisms.

Role of Lipids in Regulation of Neuroglial Interactions.

Lipids comprise an extremely heterogeneous group of compounds that perform a wide variety of biological functions. Traditional view of lipids as important structural components of the cell and compounds playing a trophic role is currently being supplemented by information on the possible participation of lipids in signaling, not only intracellular, but also intercellular. The review article discusses current data on the role of lipids and their metabolites formed in glial cells (astrocytes, oligodendrocytes, microglia) in communication of these cells with neurons. In addition to metabolic transformations of lipids in each type of glial cells, special attention is paid to the lipid signal molecules (phosphatidic acid, arachidonic acid and its metabolites, cholesterol, etc.) and the possibility of their participation in realization of synaptic plasticity, as well as in other possible mechanisms associated with neuroplasticity. All these new data can significantly expand our knowledge about the regulatory functions of lipids in neuroglial relationships.

Deficiency in the omega-3 lysolipid transporter Mfsd2a leads to aberrant oligodendrocyte lineage development and hypomyelination.

Patients with autosomal recessive microcephaly 15 caused by deficiency in the sodium-dependent lysophosphatidylcholine (LPC) transporter major facilitator superfamily domain-containing 2a (Mfsd2a) present with both microcephaly and hypomyelination, suggesting an important role for LPC uptake by oligodendrocytes in the process of myelination. Here we demonstrate that Mfsd2a is specifically expressed in oligodendrocyte precursor cells (OPCs) and is critical for oligodendrocyte development. Single-cell sequencing of the oligodendrocyte lineage revealed that OPCs from OPC-specific Mfsd2a-KO mice (2aOKO mice) underwent precocious differentiation into immature oligodendrocytes and impaired maturation into myelinating oligodendrocytes, correlating with postnatal brain hypomyelination. 2aOKO mice did not exhibit microcephaly, a finding consistent with the notion that microcephaly is the consequence of an absence of LPC uptake at the blood-brain barrier rather than a deficiency in OPCs. Lipidomic analysis showed that OPCs and iOLs from 2aOKO mice had significantly decreased levels of phospholipids containing omega-3 fatty acids, with a corresponding increase in unsaturated fatty acids, the latter being products of de novo synthesis governed by Srebp-1. RNA-Seq indicated activation of the Srebp-1 pathway and defective expression of regulators of oligodendrocyte development. Taken together, these findings indicate that the transport of LPCs by Mfsd2a in OPCs is important for maintaining OPC state to regulate postnatal brain myelination.

Electroacupuncture promotes remyelination and alleviates cognitive deficit via promoting OPC differentiation in a rat model of subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is a devastating cerebral vascular disease which causes neurological deficits including long-term cognitive deficit. Demyelination of white matter is correlated with cognitive deficit in SAH. Electroacupuncture (EA) is a traditional Chinese medical treatment which protects against cognitive deficit in varies of neurological diseases. However, whether EA exerts protective effect on cognitive function in SAH has not been investigated. The underlying mechanism of remyelination regulated by EA remains unclear. This study aimed to investigate the protective effects of EA on cognitive deficit in a rat model of SAH. SAH was induced in SD rats (n = 72) by endovascular perforation. Rats in EA group received EA treatment (10 min per day) under isoflurane anesthesia after SAH. Rats in SAH and sham groups received the same isoflurane anesthesia with no treatment. The mortality rate, neurological score, cognitive function, cerebral blood flow (CBF), and remyelination in sham, SAH and EA groups were assessed at 21 d after SAH.EA treatment alleviated cognitive deficits and myelin injury of rats compared with that in SAH group. Moreover, EA treatment enhanced remyelination in white matter and promoted the differentiation of OPCs after SAH. EA treatment inhibited the expression of Id2 and promoted the expression of SOX10 in oligodendrocyte cells. Additionally, the cerebral blood flow (CBF) of rats was increased by EA compared with that in SAH group. EA treatment exerts protective effect against cognitive deficit in the late phase of SAH. The underlying mechanisms involve promoting oligodendrocyte progenitor cell (OPC) differentiation and remyelination in white matter via regulating the expression of Id2 and SOX10. The improvement of CBF may also account for the protective effect of EA on cognitive function. EA treatment is a potential therapy for the treatment of cognitive deficit after SAH.

High Dose Pharmaceutical Grade Biotin (MD1003) Accelerates Differentiation of Murine and Grafted Human Oligodendrocyte Progenitor Cells In Vivo.

Accumulating evidences suggest a strong correlation between metabolic changes and neurodegeneration in CNS demyelinating diseases such as multiple sclerosis (MS). Biotin, an essential cofactor for five carboxylases, is expressed by oligodendrocytes and involved in fatty acid synthesis and energy production. The metabolic effect of biotin or high-dose-biotin (MD1003) has been reported on rodent oligodendrocytes in vitro, and in neurodegenerative or demyelinating animal models. However, clinical studies, showed mild or no beneficial effect of MD1003 in amyotrophic lateral sclerosis (ALS) or MS. Here, we took advantage of a mouse model of myelin deficiency to study the effects of MD1003 on the behavior of murine and grafted human oligodendrocytes in vivo. We show that MD1003 increases the number and the differentiation potential of endogenous murine oligodendroglia over time. Moreover, the levels of MD1003 are increased in the plasma and brain of pups born to treated mothers, indicating that MD1003 can pass through the mother's milk. The histological analysis of the grafted animals shows that MD1003 increased proliferation and accelerates differentiation of human oligodendroglia, but without enhancing their myelination potential. These findings provide important insights into the role of MD1003 on murine and human oligodendrocyte maturation/myelination that may explain the mitigated outcome of ALS/MS clinical trials.

Huntington disease oligodendrocyte maturation deficits revealed by single-nucleus RNAseq are rescued by thiamine-biotin supplementation.

The complexity of affected brain regions and cell types is a challenge for Huntington's disease (HD) treatment. Here we use single nucleus RNA sequencing to investigate molecular pathology in the cortex and striatum from R6/2 mice and human HD post-mortem tissue. We identify cell type-specific and -agnostic signatures suggesting oligodendrocytes (OLs) and oligodendrocyte precursors (OPCs) are arrested in intermediate maturation states. OL-lineage regulators OLIG1 and OLIG2 are negatively correlated with CAG length in human OPCs, and ATACseq analysis of HD mouse NeuN-negative cells shows decreased accessibility regulated by OL maturation genes. The data implicates glucose and lipid metabolism in abnormal cell maturation and identify PRKCE and Thiamine Pyrophosphokinase 1 (TPK1) as central genes. Thiamine/biotin treatment of R6/1 HD mice to compensate for TPK1 dysregulation restores OL maturation and rescues neuronal pathology. Our insights into HD OL pathology spans multiple brain regions and link OL maturation deficits to abnormal thiamine metabolism.

Vitamin D Promotes Remyelination by Suppressing c-Myc and Inducing Oligodendrocyte Precursor Cell Differentiation after Traumatic Spinal Cord Injury.

Demyelination due to oligodendrocytes loss occurs after traumatic spinal cord injury (TSCI). Several studies have suggested the therapeutic potential of vitamin D (VitD) in demyelinating diseases. However, experimental evidence in the context of TSCI is limited, particularly in the presence of prior VitD-deficiency. In the present study, a contusion and a transection TSCI rat model were used, representing mild and severe injury, respectively. Motor recovery was assessed in rats with normal VitD level or with VitD-deficiency after 8 weeks' treatment post-TSCI (Cholecalciferol, 500 IU/kg/day). The impact on myelin integrity was examined by transmission electron microscopy and studied in vitro using primary culture of oligodendrocytes. We found that VitD treatment post-TSCI effectively improved hindlimb movement in rats with normal VitD level irrespective of injury severity. However, cord-transected rats with prior deficiency did not seem to benefit from VitD supplementation. Our data further suggested that having sufficient VitD was essential for persevering myelin integrity after injury. VitD rescued oligodendrocytes from apoptotic cell death in vitro and enhanced their myelinating ability towards dorsal root axons. Enhanced myelination was mediated by increased oligodendrocyte precursor cells (OPCs) differentiation into oligodendrocytes in concert with c-Myc downregulation and suppressed OPCs proliferation. Our study provides novel insights into the functioning of VitD as a regulator of OPCs differentiation as well as strong preclinical evidence supporting future clinical testing of VitD for TSCI.

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

ETHNOPHARMACOLOGICAL RELEVANCE: Radix 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 STUDY: This 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 METHODS: Mice 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. RESULTS: TA 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 GSK3ß, repressed the phosphorylation of ß-catenin, reduced the expression of transcription factor 4 and inhibitor of DNA binding 2. The agonist of ß-catenin, SKL2001, partially abolished the pro-differentiation effect of TA in MO3.13 cells. CONCLUSIONS: Taken 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/ß-catenin signaling pathway. This study provides new insight into the beneficial effect of TA in the treatment of MS.

Gardenia jasminoides J. Ellis extract alleviated white matter damage through promoting the differentiation of oligodendrocyte precursor cells via suppressing neuroinflammation.

Increasing evidence has highlighted the role of white matter damage in the pathology of Alzheimer's disease (AD). Previous research has shown that a mixture of crocin analogues (GJ-4), Gardenia jasminoides J. Ellis extract, improved cognition in several AD mouse models, but the mechanism remains unclear. The aim of the present study was to investigate the effects and underlying mechanisms of GJ-4 on white matter damage. Proteomic analysis and western blotting results suggested that the level of myelin-related proteins, including myelin basic protein (MBP), myelin associated glycoprotein (MAG) and myelin associated oligodendrocyte basic protein (MOBP), was significantly decreased in the brain of PrP-hAßPPswe/PS1ΔE9 (APP/PS1) transgenic mice, and GJ-4 treatment increased the expressions of these proteins. This result revealed that GJ-4 could ameliorate myelin injury, suggesting that this might be a possible mechanism of GJ-4 on cognition. To validate the effects of GJ-4 on myelin, a metabolite of GJ-4, crocetin, which can pass through the blood-brain barrier, was applied in in vitro experiments. A mechanistic study revealed that crocetin significantly promoted the differentiation of primary cultured oligodendrocyte precursor cells to oligodendrocytes through up-regulation of nuclear Ki67 and transcription factor 2 (Olig2). Oligodendrocytes, the myelin-forming cells, have been reported to be lifelong partners of neurons. Therefore, to investigate the effects of crocetin on myelin and neurons, lysophosphatidylcholine (LPC)-treated primary mixed midbrain neuronal/glial culture was used. Immunofluorescence results indicated that crocetin treatment protected neurons and suppressed microglial activation against LPC-induced injury. To further discern the effects of GJ-4 on white matter injury and neuroinflammation, an LPC-induced mouse model was developed. GJ-4 administration increased oligodendrocyte proliferation, differentiation, and myelin repair. The mechanistic study indicated that GJ-4 improved white matter injury through the regulation of neuroinflammatory dysfunction. These data indicated that GJ-4 effectively repaired white matter damage in the LPC-treated mice. Thus, the present study supported GJ-4 as a potential therapeutic agent for AD and white matter related diseases.

Ying Yang 1 engagement in brain pathology.

Herein, we discuss data concerning the involvement of transcription factor Yin Yang 1 (YY1) in the development of brain diseases, highlighting mechanisms of its pathological actions. YY1 plays an important role in the developmental and adult pathology of the nervous system. YY1 is essential for neurulation as well as maintenance and differentiation of neuronal progenitor cells and oligodendrocytes regulating both neural and glial tissues of the brain. Lack of a YY1 gene causes many developmental abnormalities and anatomical malformations of the central nervous system (CNS). Once dysregulated, YY1 exerts multiple neuropathological actions being involved in the induction of many brain disorders like stroke, epilepsy, Alzheimer's and Parkinson's diseases, autism spectrum disorder, dystonia, and brain tumors. A better understanding of YY1's dysfunction in the nervous system may lead to the development of novel therapeutic strategies related to YY1's actions.

Chloride intracellular channel 4 (CLIC4) expression profile in the mouse medial prefrontal cortex and its regulation by ethanol.

BACKGROUND: Chloride intracellular channel 4 (CLIC4) is a multifunctional metamorphic protein for which a growing body of evidence supports a major role in the brain's molecular and behavioral responses to ethanol (EtOH). Although key to understanding the functional biology underlying this role, little is known about the cellular and subcellular expression patterns of CLIC4 in brain and how they are affected by EtOH. METHODS: We used qRT-PCR to assess Clic4 mRNA expression in the medial prefrontal cortex (mPFC) of C57BL/6J mice in the absence and presence of acute EtOH exposure. Two complementary immunohistochemical techniques were employed to assess the subcellular localization of the CLIC4 protein and its pattern of expression across brain cell types in the mPFC in the absence and presence of acute EtOH. RESULTS: Through immunohistochemical and stereological techniques, we show that CLIC4 protein is robustly expressed by oligodendrocytes (most abundant), microglia, and astrocytes, with minimal expression in neurons. Following acute EtOH exposure, we observed a rapid increase in Clic4 mRNA expression in female but not male mice and an overall increase in the number of oligodendrocytes and astrocytes expressing the CLIC4 protein. CONCLUSIONS: These findings suggest that Clic4 functions as an early response gene for acute EtOH in brain, which likely underlies its ability to modulate EtOH behavior. Our results also suggest that the role of CLIC4 in the brain's response to EtOH is mediated through oligodendrocytes.

Deciphering the spatial-temporal transcriptional landscape of human hypothalamus development.

The hypothalamus comprises various nuclei and neuronal subpopulations that control fundamental homeostasis and behaviors. However, spatiotemporal molecular characterization of hypothalamus development in humans is largely unexplored. Here, we revealed spatiotemporal transcriptome profiles and cell-type characteristics of human hypothalamus development and illustrated the molecular diversity of neural progenitors and the cell-fate decision, which is programmed by a combination of transcription factors. Different neuronal and glial fates are sequentially produced and showed spatial developmental asynchrony. Moreover, human hypothalamic gliogenesis occurs at an earlier stage of gestation and displays distinctive transcription profiles compared with those in mouse. Notably, early oligodendrocyte cells in humans exhibit different gene patterns and interact with neuronal cells to regulate neuronal maturation by Wnt, Hippo, and integrin signals. Overall, our study provides a comprehensive molecular landscape of human hypothalamus development at early- and mid-embryonic stages and a foundation for understanding its spatial and functional complexity.

Proteomic and lipidomic profiling of demyelinating lesions identifies fatty acids as modulators in lesion recovery.

After demyelinating injury of the central nervous system, resolution of the mounting acute inflammation is crucial for the initiation of a regenerative response. Here, we aim to identify fatty acids and lipid mediators that govern the balance of inflammatory reactions within demyelinating lesions. Using lipidomics, we identify bioactive lipids in the resolution phase of inflammation with markedly elevated levels of n-3 polyunsaturated fatty acids. Using fat-1 transgenic mice, which convert n-6 fatty acids to n-3 fatty acids, we find that reduction of the n-6/n-3 ratio decreases the phagocytic infiltrate. In addition, we observe accelerated decline of microglia/macrophages and enhanced generation of oligodendrocytes in aged mice when n-3 fatty acids are shuttled to the brain. Thus, n-3 fatty acids enhance lesion recovery and may, therefore, provide the basis for pro-regenerative medicines of demyelinating diseases in the central nervous system.

Evaluation of Edaravone effects on the differentiation of human adipose derived stem cells into oligodendrocyte cells in multiple sclerosis disease in rats.

AIMS: Among all the treatments for Multiple Sclerosis, stem cell transplantation, such as ADSCs, has attracted a great deal of scientific attention. On the other hand, Edaravone, as an antioxidant component, in combination with stem cells, could increase the survival and differentiation potential of stem cells. MAIN METHODS: 42 rats were divided into: Control, Cuprizone (CPZ), Sham, Edaravone (Ed), hADSCs, and Ed/hADSCs groups. Following induction of cuprizone, induced MS model, behavioral tests were designed to evaluate motor function during. Luxal fast blue staining was done to measure the level of demyelination and remyelination. Immunofluorescent staining was used to evaluate the amount of MBP, OLIG2, and MOG proteins. The mRNA levels of human MBP, MOG, and OLIG2 and rat Mbp, Mog, and Olig2 were determined via RT-PCR. KEY FINDINGS: Flow cytometry analysis exhibited that the extracted cells were positive for CD73 (93.8 ± 3%) and CD105 (91.6 ± 3%), yet negative for CD45 (2.06 ± 0.5%). Behavioral tests, unveiled a significant improvement in the Ed (P < 0.001), hADSCs (P < 0.001), and Ed/hADSCs (P < 0.001) groups compared to the others. In the Ed/hADSCs group, the myelin density was significantly higher than that in the Ed treated and hADSCs treated groups (P < 0.01). Edaravone and hADSCs increased the expression of Mbp, Mog, and Olig2 genes in the cuprizone rat models. Moreover, significant differences were seen between the Ed treated and hADSCs treated groups and the Ed/hADSCs group (P < 0.05 for Mbp and Olig2 and P < 0.01 for Mog). SIGNIFICANCE: Edaravone in combination with hADSCs reduced demyelination and increased oligodendrogenesis in the cuprizone rat models.

Screening Reveals Sterol Derivatives with Pro-Differentiation, Pro-Survival, or Potent Cytotoxic Effects on Oligodendrocyte Progenitor Cells.

Inducing the formation of new oligodendrocytes from oligodendrocyte progenitor cells (OPCs) represents a potential approach to repairing the loss of myelin observed in multiple sclerosis and other diseases. Recently, we demonstrated that accumulation of specific cholesterol precursors, 8,9-unsaturated sterols, is a dominant mechanism by which dozens of small molecules enhance oligodendrocyte formation. Here, we evaluated a library of 56 sterols and steroids to evaluate whether other classes of bioactive sterol derivatives may also influence mouse oligodendrocyte precursor cell (OPC) differentiation or survival. From this library, we identified U-73343 as a potent enhancer of oligodendrocyte formation that induces 8,9-unsaturated sterol accumulation by inhibition of the cholesterol biosynthesis enzyme sterol 14-reductase. In contrast, we found that mouse OPCs are remarkably vulnerable to treatment with the glycosterol OSW-1, an oxysterol-binding protein (OSBP) modulator that induces Golgi stress and OPC death in the low picomolar range. A subsequent small-molecule suppressor screen identified mTOR signaling as a key effector pathway mediating OSW-1's cytotoxic effects in mouse OPCs. Finally, evaluation of a panel of ER and Golgi stress-inducing small molecules revealed that mouse OPCs are highly sensitive to these perturbations, more so than closely related neural progenitor cells. Together, these studies highlight the wide-ranging influence of sterols and steroids on OPC cell fate, with 8,9-unsaturated sterols positively enhancing differentiation to oligodendrocytes and OSW-1 able to induce lethal Golgi stress with remarkable potency.

A subpopulation of embryonic microglia respond to maternal stress and influence nearby neural progenitors.

The interplay between hypothalamic neurons and microglia as they integrate stressors to regulate homeostasis is of growing interest. We asked if microglia in the embryonic hypothalamus were likewise stress responsive and, if so, whether their precocious activation perturbs nearby neural stem cell (NSC) programs. We performed single-cell transcriptomics to define embryonic hypothalamic microglia heterogeneity and identified four microglial subsets, including a subpopulation adjacent to NSCs that was responsive to gestational cold stress. Stress exposure elevated CCL3 and CCL4 secretion, but only in male brains, and ex vivo CCL4 treatment of hypothalamic NSCs altered proliferation and differentiation. Concomitantly, gestational stress decreased PVN oxytocin neurons only in male embryos, which was reversed by microglia depletion. Adult offspring exposed to gestational stress displayed altered social behaviors, which was likewise microglia dependent, but only in males. Collectively, immature hypothalamic microglia play an unappreciated role in translating maternal stressors to sexually dimorphic perturbation of neurodevelopmental programs.

Bee Venom-Derived BBB Shuttle and its Correlation with Oligodendrocyte Proliferation Markers in Mice Model of Multiple Sclerosis.

Multiple sclerosis is a chronic demyelinating disease with a functional disturbance in the immune system and axonal damages. It was shown that Apamin as a blood-brain barrier shuttle acts as a Ca2+ activated K+ channels (SK channels) blocker. In this study, the effects of Apamin on oligodendrocyte differentiation markers were evaluated on an induced model of MS. Briefly, C57BL/6 male mice (22 ± 5 g) except the control group were fed with 0.2% (w/w) cuprizone pellets for 6 weeks. After cuprizone withdrawal, mice were divided randomly into six groups. Apamin (100 µg/kg/BW) was administered intraperitoneally as a co-treatment during phase I (demyelination) or post-treatment phase II (remyelination) twice a week. Mice were anesthetized, perfused with phosphate-buffered saline, then fixed brains were coronally sectioned and the changes in oligodendrocytes markers such as Olig2, PDGFR-α, and BrdU incorporation were assessed by immunohistochemistry assay. Apamin administration increased Olig2+ cells in phase I as compared to the control group (p < 0.0001). Also, a decreasing trend in PDGFRa+ cells observed after cuprizone withdrawal (p < 0.001). 5-Bromo-2'-deoxyuridine (BrdU) incorporation test was confirmed stimulation of oligodendrocyte progenitor cell proliferation in phase I in the Apamin exposed group (p < 0.0001), especially at the subventricular zone. This study highlights the potential therapeutic effects of Apamin as a bee venom-derived peptide on oligodendrocyte precursor proliferation and elevation in myelin content in an oxidative induced multiple sclerosis model due to cuprizone exposure.

Bu Shen Yi Sui Capsule Alleviates Neuroinflammation and Demyelination by Promoting Microglia toward M2 Polarization, Which Correlates with Changes in miR-124 and miR-155 in Experimental Autoimmune Encephalomyelitis.

BACKGROUND: Bu Shen Yi Sui capsule (BSYS) is a traditional Chinese medicine prescription that has shown antineuroinflammatory and neuroprotective effects in treating multiple sclerosis (MS) and its animal model of experimental autoimmune encephalomyelitis (EAE). Microglia play an important role in neuroinflammation. The M1 phenotype of microglia is involved in the proinflammatory process of the disease, while the M2 phenotype plays an anti-inflammatory role. Promoting the polarization of microglia to M2 in MS/EAE is a promising therapeutic strategy. This study is aimed at exploring the effects of BSYS on microglial polarization in mice with EAE. METHODS: The EAE model was established by the intraperitoneal injection of pertussis toxin and subcutaneous injection of myelin oligodendrocyte glycoprotein (MOG)35-55 in C57BL/6J mice. The mice were treated with BSYS (3.02 g/kg), FTY720 (0.3 mg/kg), or distilled water by intragastric administration. H&E and LFB staining, transmission electron microscopy, qRT-PCR, immunofluorescence, ELISA, fluorescence in situ hybridization, and western blotting were used to detect the histological changes in myelin, microglial M1/M2 polarization markers, and the expression of key genes involved in EAE. Results and Conclusions. BSYS treatment of EAE mice increased the body weight, decreased the clinical score, and reduced demyelination induced by inflammatory infiltration. BSYS also inhibited the mRNA expression of M1 microglial markers while increasing the mRNA level of M2 markers. Additionally, BSYS led to a marked decrease in the ratio of M1 microglia (iNOS+/Iba1+) and an obvious increase in the number of M2 microglia (Arg1+/Iba1+). In the EAE mouse model, miR-124 expression was decreased, and miR-155 expression was increased, while BSYS treatment significantly reversed this effect and modulated the levels of C/EBP α, PU.1, and SOCS1 (target genes of miR-124 and miR-155). Therefore, the neuroprotective effect of BSYS against MS/EAE was related to promoting microglia toward M2 polarization, which may be correlated with changes in miR-124 and miR-155 in vivo.