Myelin Binding Protein Research Articles

Deleterious effect of sustained neuroinflammation in pediatric traumatic brain injury

IntroductionDespite improved management of traumatic brain injury (TBI), it still leads to lifelong sequelae and disability, particularly in children. Chronic neuroinflammation (the so-called tertiary phase), in particular, microglia/macrophage and astrocyte reactivity, is among the main mechanisms suspected of playing a role in the generation of lesions associated with TBI. The role of acute neuroinflammation is now well understood, but its persistent effect and impact on the brain, particularly during development, are not. Here, we investigated the long-term effects of pediatric TBI on the brain in a mouse model. MethodsPediatric TBI was induced in mice on postnatal day (P) 7 by weight-drop trauma. The time course of neuroinflammation and myelination was examined in the TBI mice. They were also assessed by magnetic resonance, functional ultrasound, and behavioral tests at P45. ResultsTBI induced robust neuroinflammation, characterized by acute microglia/macrophage and astrocyte reactivity. The long-term consequences of pediatric TBI studied on P45 involved localized scarring astrogliosis, persistent microgliosis associated with a specific transcriptomic signature, and a long-lasting myelination defect consisting of the loss of myelinated axons, a decreased level of myelin binding protein, and severe thinning of the corpus callosum. These results were confirmed by reduced fractional anisotropy, measured by diffusion tensor imaging, and altered inter- and intra-hemispheric connectivity, measured by functional ultrasound imaging. In addition, adolescent mice with pediatric TBI showed persistent social interaction deficits and signs of anxiety and depressive behaviors. ConclusionsWe show that pediatric TBI induces tertiary neuroinflammatory processes associated with white matter lesions and altered behavior. These results support our model as a model for preclinical studies for tertiary lesions following TBI.

Comprehensive mapping of Epithelial Na+ channel α expression in the mouse brain.

Epithelial sodium channel (ENaC) is responsible for regulating Na+ homeostasis. While its physiological functions have been investigated extensively in peripheral tissues, far fewer studies have explored its functions in the brain. Since our limited knowledge of ENaC's distribution in the brain impedes our understanding of its functions there, we decided to explore the whole-brain expression pattern of the Scnn1a gene, which encodes the core ENaC complex component ENaCα. To visualize Scnn1a expression in the brain, we crossed Scnn1a-Cre mice with Rosa26-lsl-tdTomato mice. Brain sections were subjected to immunofluorescence staining using antibodies against NeuN or Myelin Binding Protein (MBP), followed by the acquisition of confocal images. We observed robust tdTomato fluorescence not only in the soma of cortical layer 4, the thalamus, and a subset of amygdalar nuclei, but also in axonal projections in the hippocampus and striatum. We also observed expression in specific hypothalamic nuclei. Contrary to previous reports, however, we did not detect significant expression in the circumventricular organs, which are known for their role in regulating Na+ balance. Finally, we detected fluorescence in cells lining the ventricles and in the perivascular cells of the median eminence. Our comprehensive mapping of Scnn1a-expressing cells in the brain will provide a solid foundation for further investigations of the physiological roles ENaC plays within the central nervous system.

APOE ε4 is associated with reduced myelin and thus faster rate of tau PET accumulation

AbstractBackgroundMyelin is the cholesterol‐rich layer ensheathing axons in the white matter (WM). The APOE ε4 allele has been associated with both reduced cholesterol transport to myelin layers in mice and with faster tau progression in individuals with AD. Here we asked the questions whether 1) APOE ε4 is associated with lower myelin and 2) any myelin decreases mediate the association between APOE ε4 and the rate of tau‐PET accumulation in Aβ+ individuals. To assess myelin, we repurposed florbetapir‐PET tracer binding, previously shown to be sensitive to myelin binding protein in the WM (Stankow et al. Annals Neurol 2011).MethodWe included 43 Aβ‐ cognitively normal (CN, global florbetapir SUVR < 1.11) and AD‐spectrum participants (56 CN Aβ+, 32 MCI Aβ+, and 20 AD Aβ+) from ADNI. To extract individual myelin levels, we averaged each participant’s florbetapir SUVR within individual T1‐MRI based WM masks (global myelin) or 58 fiber‐tracts generated from multishell DTI (fiber‐tract myelin). To control for a putative influence by grey‐matter florbetapir levels, we adjusted the individual WM‐florbetapir SUVRs for grey‐matter florbetapir SUVR via linear regression analysis and computed z‐scores of the adjusted WM‐florbetapir SUVRs across all participants (Moscoso et al. EJNNMI, 2022). For tau‐PET, flortaucipir SUVRs were extracted in Braak‐stage GM ROIs or in the tracts’ cortical projection zones, and mixed effect linear regression was used to estimate the rate of regional flortaucipir change.ResultHigher APOE ε4 score was associated with both lower WM‐florbetapir z‐score (β = ‐0.329, p<0.001) and faster tau‐PET increase in Braak stage 3+4 ROIs (β = 0.224, p = 0.01) in Aβ+ participants (Fig. 1A&B). Using bootstrapped mediation analysis, we found that the WM‐florbetapir z‐score mediated the effect of APOE dosage on the rate of tau‐PET accumulation in Braak 3+4 (b = 2´10‐4 [95% CI: 2´10‐5, 3´10‐4], p = 0.02, Fig 1C). At the fiber‐tract level, APOE ε4 dosage exacerbated the association between decreased fiber‐tract florbetapir and faster tau‐PET increase in the tracts’ projection zones (p<0.001).ConclusionAPOE ε4 may contribute to the accumulation of tau pathology in a myelin dependent manner. Myelin impairment is treatable by several known drugs and therefore an attractive therapeutic target in AD.

Probiotic-Fermented Camel Milk Attenuates Neurodegenerative Symptoms via SOX5/miR-218 Axis Orchestration in Mouse Models.

Multiple sclerosis is an autoimmune-mediated myelin damage disorder in the central nervous system that is widespread among neurological patients. It has been demonstrated that several genetic and epigenetic factors control autoimmune encephalomyelitis (EAE), a murine model of MS, through CD4+ T-cell population quantity. Alterations in the gut microbiota influence neuroprotectiveness via unexplored mechanisms. In this study, the ameliorative effect of Bacillus amyloliquefaciens fermented in camel milk (BEY) on an autoimmune-mediated neurodegenerative model using myelin oligodendrocyte glycoprotein/complete fraud adjuvant/pertussis toxin (MCP)-immunized C57BL6j mice is investigated. Anti-inflammatory activity was confirmed in the in vitro cell model, and inflammatory cytokines interleukins IL17 (from EAE 311 to BEY 227 pg/mL), IL6 (from EAE 103 to BEY 65 pg/mL), IFNγ (from EAE 423 to BEY 243 pg/mL) and TGFβ (from EAE 74 to BEY 133 pg/mL) were significantly reduced in BEY-treated mice. The epigenetic factor miR-218-5P was identified and confirmed its mRNA target SOX-5 using in silico tools and expression techniques, suggesting SOX5/miR-218-5p could serve as an exclusive diagnostic marker for MS. Furthermore, BEY improved the short-chain fatty acids, in particular butyrate (from 0.57 to 0.85 µM) and caproic (from 0.64 to 1.33 µM) acids, in the MCP mouse group. BEY treatment significantly regulated the expression of inflammatory transcripts in EAE mice and upregulated neuroprotective markers such as neurexin (from 0.65- to 1.22-fold) (p < 0.05), vascular endothelial adhesion molecules (from 0.41- to 0.76-fold) and myelin-binding protein (from 0.46- to 0.89-fold) (p < 0.03). These findings suggest that BEY could be a promising clinical approach for the curative treatment of neurodegenerative diseases and could promote the use of probiotic food as medicine.

In Vivo Assessment of the Ameliorative Impact of Some Medicinal Plant Extracts on Lipopolysaccharide-Induced Multiple Sclerosis in Wistar Rats.

Multiple sclerosis is a chronic autoimmune disorder that leads to the demyelination of nerve fibers, which is the major cause of non-traumatic disability all around the world. Herbal plants Nepeta hindustana L., Vitex negundo L., and Argemone albiflora L., in addition to anti-inflammatory and anti-oxidative effects, have shown great potential as neuroprotective agents. The study was aimed to develop a neuroprotective model to study the effectiveness of herbal plants (N. hindustana, V. negundo, and A. albiflora) against multiple sclerosis. The in vivo neuroprotective effects of ethanolic extracts isolated from N. hindustana, V. negundo, and A. albiflora were evaluated in lipopolysaccharides (LPS) induced multiple sclerosis Wistar rat model. The rat models were categorized into seven groups including group A as normal, B as LPS induced diseased group, while C, D, E, F, and G were designed as treatment groups. Histopathological evaluation and biochemical markers including stress and inflammatory (MMP-6, MDA, TNF-α, AOPPs, AGEs, NO, IL-17 and IL-2), antioxidant (SOD, GSH, CAT, GPx), DNA damage (Isop-2α, 8OHdG) as well as molecular biomarkers (RAGE, Caspase-8, p38) along with glutamate, homocysteine, acetylcholinesterase, and myelin binding protein (MBP) were investigated. The obtained data were analyzed using SPSS version 21 and GraphPad Prism 8.0. The different extract treated groups (C, D, E, F, G) displayed a substantial neuroprotective effect regarding remyelination of axonal terminals and oligodendrocytes migration, reduced lymphocytic infiltrations, and reduced necrosis of Purkinje cells. The levels of stress, inflammatory, and DNA damage markers were observed high in the diseased group B, which were reduced after treatments with plant extracts. The antioxidant activity was significantly reduced in diseased induced group B, however, their levels were raised after treatment with plant extract. Group F (a mélange of all the extracts) showed the most significant change among all other treatment groups (C, D, E, G). The communal dose of selected plant extracts regulates neurodegeneration at the cellular level resulting in restoration and remyelination of axonal neurons. Moreover, 400 mg/kg dose of three plants in conjugation (Group F) were found to be more effective in restoring the normal activities of all measured parameters than independent doses (Group C, D, E) and is comparable with standard drug nimodipine (Group G) clinically used for the treatment of multiple sclerosis. The present study, for the first time, reported the clinical evidence of N. hindustana, V. negundo, and A. albiflora against multiple sclerosis and concludes that all three plants showed remyelination as well neuroprotective effects which may be used as a potential natural neurotherapeutic agent against multiple sclerosis.

Abstract 86: Dicer Ablation In Oligodendrocytes Impairs Oligodendrogenesis And Functional Recovery After Stroke

Introduction: Stroke-induced oligodendrogenesis contributes to ischemic brain remodeling and spontaneous functional recovery. Genes that regulate microRNA biogenesis in stroke-induced oligodendrogenesis remain little known. Methods: We employed a transgenic mouse line with conditional and inducible ablation of Dicer, a key gene of miRNA biogenesis, in myelin proteolipid protein (PLP) lineage oligodendrocytes (Dicer-KO). A PLP reporter mouse line was used as a control. Mice were subjected to transient (60min) middle cerebral artery occlusion (MCAO, n=8/group). An array of behavioral and cognitive tests were performed. All mice were sacrificed at 28 days after MCAO. Fluorescence-activated cell sorting (FACS) in combination with miRNA sequencing were used to profile the miRNA alteration. Results: Compared to ischemic reporter mice, ischemic Dicer-KO mice exhibited significantly increased infarct volumes and significantly impaired neurological outcomes and cognitive deficits post stroke as assayed by social recognition memory, novel object recognition, and Morris water-maze tests. Immunochemistry analysis revealed that ischemic Dicer-KO mice showed a significant reduction of the number of PLP-lineage NG2 + oligodendrocyte precursor cells (OPCs) and APC + myelinating oligodendrocytes compared to ischemic reporter mice. Moreover, Dicer-KO mice exhibited a robust reduction of myelinated axons measured by myelin binding protein (MBP) and Bielschowsky/Luxol Fast Blue assay. FACS analysis of PLP-lineage cells in peri-infarct regions showed that ablation of Dicer significantly decreased many miRNAs including the miR-200 family that are known to regulate oligodendrogenesis. Conclusion: Our data indicate that Dicer in PLP lineage oligodendrocytes is required for stroke-induced oligodendrogenesis and myelination, and that Dicer is involved in spontaneous functional recovery after stroke.

Paeoniflorin treatment regulates TLR4/NF-κB signaling, reduces cerebral oxidative stress and improves white matter integrity in neonatal hypoxic brain injury.

Neonatal hypoxia/ischemia (H/I), injures white matter, results in neuronal loss, disturbs myelin formation, and neural network development. Neuroinflammation and oxidative stress have been reported in neonatal hypoxic brain injuries. We investigated whether Paeoniflorin treatment reduced H/I-induced inflammation and oxidative stress and improved white matter integrity in a neonatal rodent model. Seven-day old Sprague–Dawley pups were exposed to H/I. Paeoniflorin (6.25, 12.5, or 25 mg/kg body weight) was administered every day via oral gavage from postpartum day 3 (P3) to P14, and an hour before induction of H/I. Pups were sacrificed 24 h (P8) and 72 h (P10) following H/I. Paeoniflorin reduced the apoptosis of neurons and attenuated cerebral infarct volume. Elevated expression of cleaved caspase-3 and Bad were regulated. Paeoniflorin decreased oxidative stress by lowering levels of malondialdehyde and reactive oxygen species generation and while, and it enhanced glutathione content. Microglial activation and the TLR4/NF-κB signaling were significantly down-regulated. The degree of inflammatory mediators (interleukin 1β and tumor necrosis factor-α) were reduced. Paeoniflorin markedly prevented white matter injury via improving expression of myelin binding protein and increasing O1-positive olidgodendrocyte and O4-positive oligodendrocyte counts. The present investigation demonstrates the potent protective efficiency of paeoniflorin supplementation against H/I-induced brain injury by effectually preventing neuronal loss, microglial activation, and white matter injury via reducing oxidative stress and inflammatory pathways.

Mutant Profilin1 Aggregation in Amyotrophic Lateral Sclerosis: An in Vivo Biochemical Analysis.

Introduction:Profilin1 (PFN1) is a ubiquitously expressed protein known for its function as a regulator of actin polymerization and dynamics. A recent discovery linked mutant PFN1 to Amyotrophic Lateral Sclerosis (ALS), which is a fatal and progressive motor neuron disease. We have also demonstrated that Gly118Val mutation in PFN1 is a cause of ALS, and the formation of aggregates containing mutant PFN1 may be a mechanism for motor neuron death. Hence, we were interested in investigating the aggregation of PFN1 further and searching for co-aggregated proteins in our mouse model overexpressing mutant PFN1.Methods:We investigated protein aggregation in several tissues of transgenic and notransgenic mice using western blotting. To further understand the neurotoxicity of mutant PFN1, we conducted a pull-down assay using an insoluble fraction of spinal cord lysates from hPFN1G118V transgenic mice. For this assay, we expressed His6-tagged PFN1WT and PFN1G118V in E. coli and purified these proteins using the Ni-NTA column.Results:In this study, we demonstrated that mutant PFN1 forms aggregate in the brain and spinal cord of hPFN1G118V mice, while WT-PFN1 remains soluble. Among these tissues, spinal cord lysates were found to have PFN1 bands at higher molecular weights recognized with anti-PFN1. Moreover, the pull-down assay using His6-PFN1G118V showed that Myelin Binding Protein (MBP) was present in the insoluble fraction.Conclusion:Our analysis of PFN1 aggregation in vivo revealed further details of mutant PFN1 aggregation and its possible complex formation with other proteins, providing new insights into the ALS mechanism.

Ninjurin 1 mediates peripheral nerve regeneration through Schwann cell maturation of NG2-positive cells

Ninjurin 1 (Ninj1) is identified as a peripheral nerve injury-induced protein. However, the role of Ninj1 in nerve regeneration is unclear. Schwann cells (SCs) and microvasculature are critical for peripheral nerve regeneration. SCs precursors and microvascular pericytes (PCs), which are nerve/glial antigen 2 (NG2)-positive cells are observed in peripheral nervous system. In this study, we investigated the role of Ninj1 in peripheral nerve regeneration using NG2+cell-specific inducible deletion of Ninj1 mouse model.The number of NG2+cells, which were associated with and without microvessels was increased after sciatic nerve crush injury. There was a significant increase in the expression of Ninj1 and EphA7 in the injured nerve tissue. This increase was mostly observed in NG2+cells. Genetic tracing of NG2+cells was performed using tamoxifen (Tam) treatment on NG2CreERT:R26R-tdTomato mice. The sciatic nerve was injured following the Tam-treatment, then tdTomato-expressing SCs were mostly observed in regenerated SCs at 21 days after nerve injury. Ninj1 gene knockout (Ninj1 KO) in NG2+cells was induced using NG2CreERT:Ninj1loxp mice. Tam-treated-NG2CreERT or Tam-nontreated NG2CreERT:Ninj1loxp mice were used as controls. Following Tam-treatment, the sciatic nerve in each group was injured. Ninj1KO significantly attenuated the expression of the myelin binding protein (MBP) as well as the number of myelinated axons. The expression of MBP in cultured SCs was significantly reduced by SiRNA-mediated Ninj1 knockdown (KD). Ninj1KD also attenuated the differentiation of SCs by isolated EphA7+multipotent PCs.The current data indicate that Ninj1 plays a vital role in peripheral nerve regeneration. This is observed particularly in the myelination process of NG2+cells including SCs precursors and multipotent PCs.

A blend containing docosahexaenoic acid, arachidonic acid, vitamin B12, vitamin B9, iron and sphingomyelin promotes myelination in an in vitro model

ABSTRACT During the development of the central nervous system, oligodendrocytes (OLs) are responsible for myelination, the formation of the myelin sheath around axons. This process enhances neuronal connectivity and supports the maturation of emerging cognitive functions. In humans, recent evidence suggests that early life nutrition may affect myelination. In the present study, we investigated the impact of a blend containing docosahexaenoic acid, arachidonic acid, vitamin B12, vitamin B9, iron and sphingomyelin, or each of these nutrients individually, on oligodendrocyte precursor cells (OPCs) proliferation and maturation into OLs as well as their myelinating properties. By using an in vitro model, developed to study each step of myelination, we found that the nutrient blend increased the number of OPCs and promoted their differentiation and maturation into OLs, as measured by quantifying A2B5 positive cells, myelin-associated glycoprotein (MAG) positive cells and area, myelin binding protein (MBP) positive cells and area, respectively. Moreover, measuring myelination by quantifying the overlapping signal between neurofilament and either MAG or MBP revealed a positive effect of the blend on OLs myelinating properties. In contrast, treatment with each individual nutrient resulted in differential effects on the various readouts. This work suggests that dietary intake of these nutrients during early life, might be beneficial for myelination.

Improvement of fiber connectivity and functional recovery after stroke by montelukast, an available and safe anti-asthmatic drug

Stroke is one of the main causes of death, neurological dysfunctions or disability in elderly. Neuroprotective drugs have been proposed to improve long-term recovery after stroke, but failed to reach clinical effectiveness. Hence, recent studies suggested that restorative therapies should combine neuroprotection and remyelination. Montelukast, an anti-asthmatic drug, was shown to exert neuroprotection in animal models of CNS injuries, but its ability to affect oligodendrocytes, restoring fiber connectivity, remains to be determined.In this study, we evaluated whether montelukast induces long-term repair by promoting fiber connectivity up to 8 weeks after middle cerebral artery occlusion (MCAo), using different experimental approaches such as in vivo diffusion magnetic resonance imaging (MRI), electrophysiological techniques, ex vivo diffusion tensor imaging (DTI)-based fiber tracking and immunohistochemistry. We found that, in parallel with a reduced evolution of ischemic lesion and atrophy, montelukast increased the DTI-derived axial diffusivity and number of myelin fibers, the density of myelin binding protein (MBP) and the number of GSTpi+ mature oligodendrocytes. Together with the rescue of MCAo-induced impairments of local field potentials in ischemic cortex, the data suggest that montelukast may improve fibers reorganization.Thus, to ascertain whether this effect involved changes of oligodendrocyte precursor cells (OPCs) activation and maturation, we used the reporter GPR17iCreERT2:CAG-eGreen florescent protein (GFP) mice that allowed us to trace the fate of OPCs throughout animal’s life. Our results showed that montelukast enhanced the OPC recruitment and proliferation at acute phase, and increased their differentiation to mature oligodendrocytes at chronic phase after MCAo.Considering the crosstalk between OPCs and microglia has been widely reported in the context of demyelinating insults, we also assessed microglia activation. We observed that montelukast influenced the phenotype of microglial cells, increasing the number of M2 polarized microglia/macrophages, over the M1 phenotype, at acute phase after MCAo.In conclusion, we demonstrated that montelukast improves fiber re-organization and long-term functional recovery after brain ischemia, enhancing recruitment and maturation of OPCs. The present data suggest that montelukast, an already approved drug, could be “repositioned “as a protective drug in stroke acting also on fiber re-organization.

An augmentation in histone dimethylation at lysine nine residues elicits vision impairment following traumatic brain injury

Traumatic Brain Injury (TBI) affects more than 1.7 million Americans each year and about 30% of TBI-patients having visual impairments. The loss of retinal ganglion cells (RGC) in the retina and axonal degeneration in the optic nerve have been attributed to vision impairment following TBI; however, the molecular mechanism has not been elucidated. Here we have shown that an increase in histone di-methylation at lysine 9 residue (H3K9Me2), synthesized by the catalytic activity of a histone methyltransferase, G9a is responsible for RGC loss and axonal degeneration in the optic nerve following TBI. To elucidate the molecular mechanism, we found that an increase in H3K9Me2 results in the induction of oxidative stress both in the RGC and optic nerve by decreasing the mRNA level of antioxidants such as Superoxide dismutase (sod) and catalase through impairing the transcriptional activity of Nuclear factor E2-related factor 2 (Nrf2) via direct interaction. The induction of oxidative stress is associated with death in RGC and oligodendrocyte precursor cells (OPCs). The death in OPCs is correlated with a reduction in myelination, and the expression of myelin binding protein (MBP) in association with degeneration of neurofilaments in the optic nerve. This event allied to an impairment of the retrograde transport of axons and loss of nerve fiber layer in the optic nerve following TBI. An administration of G9a inhibitor, UNC0638 attenuates the induction of H3K9Me2 both in RGC and optic nerve and subsequently activates Nrf2 to reduce oxidative stress. This event was concomitant with the rescue in the loss of retinal thickness, attenuation in optic nerve degeneration and improvement in the retrograde transport of axons following TBI.

Effect of Multiple Intraperitoneal Injections of Human Bone Marrow Mesenchymal Stem Cells on Cuprizone Model of Multiple Sclerosis

Background:Bone marrow mesenchymal stem cells (BM-MSCs) elicit neuroprotective effects, and their repair ability has been investigated in different experimental models. We aimed to investigate the effect of multiple i.p. BM-MSCs injections in the cuprizone model of multiple sclerosis in mice.Methods:Adult male C57BL/6 mice (n = 40) were fed a regular diet or a diet containing cuprizone (0.2% w/w) for six weeks. Bone marrow samples were taken from patients with spinal cord injury. BM-MSCs (2 × 106 in 1 milliliter medium) were administered intraperitoneally for two consecutive weeks at the end of the forth weeks of cuprizone administration. Animals (n = 12) were perfused with 10% paraformaldehyde at the end of sixth week. The brains were sectioned coronally in 6-8-μm thickness (-2.3 to 1.8 mm from bregma). The sections were stained by luxol fast blue-cresyl violet, and images were captured via a microscope. Demyelination ratio was estimated in corpus callosum in a blind manner. A quantitative real-time PCR was used to measure the myelin basic protein gene expression at sixth week.Results:Histologically, cuprizone induced demyelination in the corpus callosum. Demyelinated area was diminished in the corpus callosum of cell-administered group. Cuprizone could decrease myelin-binding protein mRNAs expression in corpus callosum, which was significantly recovered after BM-MSCs injections.Conclusion:Our data indicated a remyelination potency of multiple i.p. BM-MSCs in the cuprizone model of multiple sclerosis in mice.

Derivation of telencephalic oligodendrocyte progenitors from human pluripotent stem cells.

Oligodendrocytes are the main myelinating cell of the adult CNS and are vulnerable to injury in diverse disorders such as spinal cord injury, stroke, trauma, pharmacological and radiation toxicity, as well as neuroinflammation. Human pluripotent stem cells are attractive sources of oligodendrocyte lineage cells and provide a promising treatment strategy for exogenous myelin repair through transplantation. This unit describes a protocol for the step-wise differentiation of forebrain late oligodendrocyte progenitor cells (OPCs) from human pluripotent stem cells in defined chemical in vitro culture conditions. It involves a stepwise progression of oligodendrocyte progenitors through their known developmental phases, starting with the expression of appropriate transcription factors (Olig2, Nkx2.2), the upregulation of PDGFRA, followed by the appearance of O4-expressing cells, then O1 expression and finally mature myelin-binding protein (MBP) expressing cells. Validation of cell fate is performed by extensive transcriptomal profiling, as well in vitro myelination essays with hESCs derived neuronal cells. Recapitulating forebrain oligodendrocyte development may generate cells more suitable for transplantation strategies for disorders primarily involving the telencephalon.

Activation of the niacin receptor HCA2 reduces demyelination and neurofilament loss, and promotes functional recovery after spinal cord injury in mice

After spinal cord injury (SCI), there is an acute phase of alternatively activated (M2) macrophage infiltration, followed by a long-lasting phase of classically activated (M1) macrophage accumulation in the wound, which is believed to derail healing and compromize organ functions. Thus, agents which are able to modulate macrophage phenotypes may provide significant benefits to SCI patients. In the present study, we demonstrate that the niacin receptor HCA2 is specifically expressed on the cell surface of M1 but not M2 macrophages. Treatment of M1 macrophages with niacin (300μM) resulted in down-regulation of the p65 NF-κB phosphorylation, associated with a marked decrease in the levels of M1 markers, including CD86, IL-12, and IL-6, and a significant increase in the expressions of M2 markers, such as CD206, IL-10, and IL-13, suggesting that niacin causes a shift of M1 to M2. Moreover, treatment of the M1-oligodendrocyte precursor cell (OPC) co-cultures with niacin markedly promoted the expression of myelin binding protein (MBP). After SCI in C57/BL6 mice for a week, a marked accumulation of M1 macrophages, which expressed HCA2 receptor, was evident in the wound. Treatment of the SCI mice with niacin (100mg/kg) resulted in a dramatic decrease in the number of M1 macrophages and a significant increase in the number of M2 macrophages in the wound. This was associated with a robust inflammation resolution, attenuation of demyelination and neurofilament loss, and significant improvement of locomotor function. Thus, HCA2 receptor may serve as a therapeutic target to promote post-SCI recovery.

Nanoparticle-Delivered IRF5 siRNA Facilitates M1 to M2 Transition, Reduces Demyelination and Neurofilament Loss, and Promotes Functional Recovery After Spinal Cord Injury in Mice.

Macrophage activation and persistent inflammation contribute to the pathogenesis of spinal cord injury (SCI), and different phenotypes of macrophages play diverse roles in the pathological process of SCI. After SCI, there is an acute phase of alternatively activated (M2) macrophage infiltration, followed by a long-lasting phase of classically activated (M1) macrophage accumulation in the wound. The long-lasting predominance of M1 macrophages may derail healing and compromise organ functions. Based on the previous findings that the transcription factor interferon regulatory factor 5 (IRF5) up-regulates genes associated with M1 macrophages, we attempted to examine the effect of silencing IRF5 on SCI progression. IRF5 expression was assessed with Western blotting or immunohistochemistry. Macrophage phenotypes were measured with flow cytometry or immunohistochemistry. M1- or M2-related cytokines were measured with a Luminex assay kit. IRF5 siRNA was delivered into the macrophages infiltrated into the wound of SCI mice through lipidoid nanoparticle. Locomotor functions were measured with Basso Mouse Scale (BMS) scoring. Myelination was assessed with luxol fast blue staining. Myelin binding protein, neurofilaments, synaptic markers, and cytokines in the wound area were measured with Western blotting. The Mann-Whitney U test was used for statistical analyses. After SCI, significant elevation of IRF5 was evident on day 1, peaked on day 7, and gradually decreased thereafter. Similar dynamic change in the expression of CD86, a typical M1 marker, was observed. In contrast, there was a transient increase in the expression of CD206, a typical M2 marker, which peaked 6h after SCI, and returned to baseline within 1day. Macrophages isolated from the epicenter at day 3 after SCI were predominantly M1 phenotype, and a siRNA-mediated knockdown of IRF5 resulted in a reduced expression of M1 macrophage markers and increased expression of M2 macrophage markers. Nanoparticle-mediated delivery of IRF5 siRNA to SCI mouse model resulted in a dramatic decrease in the number of M1 macrophages and a significant increase in the number of M2 macrophages in the wound. This was associated with a robust inflammation resolution, attenuation of demyelination and neurofilament loss, and significant improvement of locomotor function (p < 0.05). IRF5 may serve as a therapeutic target to promote post-SCI recovery.

Kindling-induced learning deficiency and possible cellular and molecular involved mechanisms

Hippocampus learning disturbance is a major symptom of patients with seizure, hence hippocampal dysfunction has essential role in worsening the disease. Hippocampal formation includes neurons and myelinated fibers that are necessary for acquisition and consolidation of memory, long-term potentiation and learning activity. The exact mechanism by which seizure can decrease memory and learning activity of hippocampus remains unknown. In the present study, electrical kindling-induced learning deficit in rats was evaluated by Morris water maze (MWM) test. The hippocampus was removed and changes in neurons and myelin sheaths around hippocampal fibers were investigated using histological and immunohistochemical methods. Demyelination was assessed by luxol fast blue staining, and immunohistological staining of myelin-binding protein (MBP). The TUNEL assay was used for evaluation of neuronal apoptosis and the glial fibriliary acetic protein (GFAP) was used for assessment of inflammatory reaction. The results indicated that electrical kindling of hippocampus could induce deficiency in spatial learning and memory as compared to control group. In addition, electrical kindling caused damage to the myelin sheath around hippocampal fibers and produced vast demyelination. Furthermore, an increase in the number of apoptotic cells in hippocampal slices was observed. In addition, inflammatory response was higher in kindled animals as compared to the control group. The results suggested that the decrease in learning and memory in kindled animals is likely due to demyelination and augmentation in apoptosis rate accompanied by inflammatory reaction in hippocampal neurons of kindled rats.

Growth Defects and Impaired Cognitive–Behavioral Abilities in Mice with Knockout for Eif4h, a Gene Located in the Mouse Homolog of the Williams-Beuren Syndrome Critical Region

Protein synthesis is a tightly regulated, energy-consuming process. The control of mRNA translation into protein is fundamentally important for the fine-tuning of gene expression; additionally, precise translational control plays a critical role in many cellular processes, including development, cellular growth, proliferation, differentiation, synaptic plasticity, memory, and learning. Eukaryotic translation initiation factor 4h (Eif4h) encodes a protein involved in the process of protein synthesis, at the level of initiation phase. Its human homolog, WBSCR1, maps on 7q11.23, inside the 1.6 Mb region that is commonly deleted in patients affected by the Williams-Beuren syndrome, which is a complex neurodevelopmental disorder characterized by cardiovascular defects, cerebral dysplasias and a peculiar cognitive-behavioral profile. In this study, we generated knockout mice deficient in Eif4h. These mice displayed growth retardation with a significant reduction of body weight that began from the first week of postnatal development. Neuroanatomical profiling results generated by magnetic resonance imaging analysis revealed a smaller brain volume in null mice compared with controls as well as altered brain morphology, where anterior and posterior brain regions were differentially affected. The inactivation of Eif4h also led to a reduction in both the number and complexity of neurons. Behavioral studies revealed severe impairments of fear-related associative learning and memory formation. These alterations suggest that Eif4h might contribute to certain deficits associated with Williams-Beuren syndrome.

Evaluation of the multipotent character of human foreskin-derived precursor cells

In the present study, the trilineage differentiation capacity of human foreskin-derived precursor cells (hSKP) was evaluated upon exposure to various (non)commercial (i and ii) ectodermal, (iii) mesodermal and (iv) endodermal differentiation media. (i) Upon sequential exposure of the cells to keratinocyte growth (CnT-07® or CnT-057®) and differentiation (CnT-02® or Epilife®) media, keratinocyte-like cells (filaggrin +/involucrin +) were obtained. The preferred keratinocyte differentiation strategy was exposure to CnT-07®. (ii) When hSKP were subsequently exposed to NeuroCult® media, cells underwent a weak neuro-ectodermal differentiation expressing nestin, myelin binding protein (MBP), vimentin and alpha-foetoprotein (AFP). Sequential exposure to NPMM® and NPDM® generated cells with an inferior neuro-ectodermal phenotype (nestin +/vimentin +/MBP −/AFP −). (iii) Upon exposure of hSKP to insulin–transferrin–selenite (ITS) and dexamethasone, small lipid droplets were observed, suggesting their differentiation potential towards adipocyte-like cells. (iv) Finally, after sequential exposure to hepatogenic growth factors and cytokines, an immature hepatic cell population was generated. The presence of pre-albumin suggests that a sequential exposure strategy is here superior to a cocktail approach. In summary, a considerable impact of different (non)commercial media on the lineage-specific differentiation efficiency of hSKP is shown. In addition, we demonstrate here for the first time that, in a suitable keratinocyte stimulating micro-environment, hSKP can generate keratinocyte-like progeny in vitro.

Effect of hypothyroxinemia on thyroid hormone responsiveness and action during rat postnatal neocortical development

Neurological deficits due to maternal and neonatal hypothyroxinemia under mild–moderate iodine deficiency are a major preventable health problem worldwide. The present study assesses the impact of hypothyroxinemia on postnatal neocortical development and also compares it to the known effects of severe hypothyroidism. Our results strongly suggest that even within elevated circulating triiodothyronine (T3) levels, hypothyroxinemia significantly impairs thyroid hormone responsiveness in developing rat neocortex. The significant compensatory alteration in deiodinase levels with unaltered monocarboxylate transporter 8 (MCT8) and thyroid hormone receptors (TRs), although found to be similar in hypothyroxinemic and hypothyroid condition, is more pronounced under later condition. The resultant downregulation of nuclear myelin binding protein (MBP) and mitochondrial transcripts Cytochrome oxidase III (Cox III) as well as significantly enhanced mitochondrial localization of Bax and reduced Bcl-2 and Bcl-xL accompanied by enhanced release of Cytochrome c and Smac with activation of caspase-3 indicates pronounced apoptosis leading to compromised cellular survival. The similarities of this responsiveness albeit with difference in degree under hypothyroidism and hypothyroxinemic state with adequate availability of T3 are suggestive of an independent role of thyroxine in neocortex development. Taken together, this study brings forth the neurophysiological aspects of hypothyroxinemia and underscores the importance of adequate iodine nutrition along with mandatory thyroxin monitoring during pregnancy and after birth.