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Mesenchymal stem-cell-derived small extracellular vesicles (MSC-EVs), as a therapeutic agent, have shown great promise in the treatment of neurological diseases. To date, the neurorestorative effects and underlying mechanism of MSC-EVs in Alzheimer’s disease (AD) are not well known. Herein, we aimed to investigate the action of MSC-EVs on the neuronal deficits in β-amyloid protein (Aβ)-stimulated hippocampal neurons, or AD cell (SHSY5Y cell lines) and animal (APPswe / PS1dE9 mice) models. In the present study, the cell and AD models received a single-dose of MSC-EVs, and were then assessed for behavioral deficits, pathological changes, intracellular calcium transients, neuronal morphology alterations, or electrophysiological variations. Additionally, the nuclear factor E2-related factor 2 (Nrf2, a key mediator of neuronal injury in AD) signaling pathway was probed by western blotting in vitro and in vivo models of AD. Our results showed that MSC-EVs therapy improved the cognitive impairments and reduced the hippocampal Aβ aggregation and neuronal loss in AD mice. Markedly, EV treatment restored the calcium oscillations, dendritic spine alterations, action potential abnormalities, or mitochondrial changes in the hippocampus of AD models. Also, we found that the Nrf2 signaling pathway participated in the actions of MSC-EVs in the cell and animal models. Together, these data indicate that MS-EVs as promising nanotherapeutics for restoration of hippocampal neuronal morphology and function in APP / PS1 mice, further highlighting the clinical values of MSC-EVs in the treatment of AD.

Retinal Ganglion Cells (RGCs) lose their ability to grow axons during development. Adult RGCs thus fail to regenerate their axons after injury, leading to vision loss. To uncover mechanisms that promote regeneration of RGC axons, we identified transcription factors (TF) and open chromatin regions that are enriched in rat embryonic RGCs (high axon growth capacity) compared to postnatal RGCs (low axon growth capacity). We found that developmental stage-specific gene expression changes correlated with changes in promoter chromatin accessibility. Binding motifs for TFs such as CREB, CTCF, JUN and YY1 were enriched in the regions of the chromatin that were more accessible in embryonic RGCs. Proteomic analysis of purified rat RGC nuclei confirmed the expression of TFs with potential role in axon growth such as CREB, CTCF, YY1, and JUND. The CREB/ATF binding motif was widespread at the open chromatin region of known pro-regenerative TFs, supporting a role of CREB in regulating axon regeneration. Consistently, overexpression of CREB fused to the VP64 transactivation domain in mouse RGCs promoted axon regeneration after optic nerve injury. Our study provides a map of the chromatin accessibility during RGC development and highlights that TF associated with developmental axon growth can stimulate axon regeneration in mature RGC.

Electroencephalographic synchrony can help assess brain network status; however, its usefulness has not yet been fully proven. We developed a clinically feasible method that combines the phase synchrony index (PSI) with resting-state 19-channel electroencephalography (EEG) to evaluate post-stroke motor impairment. In this study, we investigated whether our method could be applied to aphasia, a common post-stroke cognitive impairment. This study included 31 patients with subacute aphasia and 24 healthy controls. We assessed the expressive function of patients and calculated the PSIs of three motor language-related regions: frontofrontal, left frontotemporal, and right frontotemporal. Then, we evaluated post-stroke network alterations by comparing PSIs of the patients and controls and by analyzing the correlations between PSIs and aphasia scores. The frontofrontal PSI (beta band) was lower in patients than in controls and positively correlated with aphasia scores, whereas the right frontotemporal PSI (delta band) was higher in patients than in controls and negatively correlated with aphasia scores. Evaluation of artifacts suggests that this association is attributed to true synchrony rather than spurious synchrony. These findings suggest that post-stroke aphasia is associated with alternations of two different networks and point to the usefulness of EEG PSI in understanding the pathophysiology of aphasia.

Stem cell transplantation proved promising in animal models of neurological diseases; however, in conditions with disseminated pathology such as ALS, delivery of cells and their broad distribution is challenging. To address this problem, we explored intra-arterial (IA) delivery route, of stem cells. The goal of this study was to investigate the feasibility and safety of MRI-guided transplantation of glial restricted precursors (GRPs) and mesenchymal stem cells (MSCs) in dogs suffering from ALS-like disease, degenerative myelopathy (DM). Canine GRP transplantation in dogs resulted in rather poor retention in the brain, so MSCs were used in subsequent experiments. To evaluate the safety of MSC intraarterial transplantation, naïve pigs (n = 3) were used as a pre-treatment control before transplantation in dogs. Cells were labeled with iron oxide nanoparticles. For IA transplantation a 1.2-French microcatheter was advanced into the middle cerebral artery under roadmap guidance. Then, the cells were transplanted under real-time MRI with the acquisition of dynamic T2*-weighted images. The procedure in pigs has proven to be safe and histopathology has demonstrated the successful and predictable placement of transplanted porcine MSCs. Transplantation of canine MSCs in DM dogs resulted in their accumulation in the brain. Interventional and follow-up MRI proved the procedure was feasible and safe. Analysis of gene expression after transplantation revealed a reduction of inflammatory factors, which may indicate a promising therapeutic strategy in the treatment of neurodegenerative diseases.

Gaze stability is the ability of the eyes to fixate a stable point when the head is moving in space. Because gaze stability is impaired in peripheral vestibular loss patients, gaze stabilization exercises are often prescribed to facilitate compensation. However, both the assessment and prescription of these exercises are subjective. Accordingly, here we quantified head motion kinematics in patients with vestibular loss while they performed the standard of care gaze stability exercises, both before and after surgical deafferentation. We also correlate the head kinematic data with standard clinical outcome measures. Using inertial measurement units, we quantified head movements in patients as they transitioned through these two vestibular states characterized by different levels of peripheral damage. Comparison with age-matched healthy control subjects revealed that the same kinematic measurements were significantly abnormal in patients both pre- and post-surgery. Regardless of direction, patients took a longer time to move their heads during the exercises. Interestingly, these changes in kinematics suggest a strategy that existed preoperatively and remained symmetric after surgery although the patients then had complete unilateral vestibular loss. Further, we found that this kinematic assessment was a good predictor of clinical outcomes, and that pre-surgery clinical measures could predict post-surgery head kinematics. Thus, together, our results provide the first experimental evidence that patients show significant changes in head kinematics during gaze stability exercises, even prior to surgery. This suggests that early changes in head kinematic strategy due to significant but incomplete vestibular loss are already maladaptive as compared to controls.

Spinal cord injury (SCI) leads to dramatic impairments of motor, sensory, and autonomic functions of affected individuals. Following the primary injury, there is an increased release of glutamate that leads to excitotoxicity and further neuronal death. Therefore, modulating glutamate excitotoxicity seems to be a promising target to promote neuroprotection during the acute phase of the injury. In this study, we evaluated the therapeutic effect of a FDA approved antiepileptic drug (levetiracetam-LEV), known for binding to the synaptic vesicle protein SV2A in the brain and spinal cord. LEV therapy was tested in two models of SCI—one affecting the cervical and other the thoracic level of the spinal cord. The treatment was effective on both SCI models. Treated animals presented significant improvements on gross and fine motor functions. The histological assessment revealed a significant decrease of cavity size, as well as higher neuronal and oligodendrocyte survival on treated animals. Molecular analysis revealed that LEV acts by stabilizing the astrocytes allowing an effective uptake of the excess glutamate from the extracellular space. Overall, our results demonstrate that Levetiracetam may be a promising drug for acute management of SCI.

Auditory neuropathy is caused by the loss of afferent input to the brainstem via the components of the neural pathway comprising inner hair cells and the first order neurons of the spiral ganglion. Recent work has identified the synapse between cochlear primary afferent neurons and sensory hair cells as a particularly vulnerable component of this pathway. Loss of these synapses due to noise exposure or aging results in the pathology identified as hidden hearing loss, an initial stage of cochlear dysfunction that goes undetected in standard hearing tests. We show here that repulsive axonal guidance molecule a (RGMa) acts to prevent regrowth and synaptogenesis of peripheral auditory nerve fibers with inner hair cells. Treatment of noise-exposed animals with an anti-RGMa blocking antibody regenerated inner hair cell synapses and resulted in recovery of wave-I amplitude of the auditory brainstem response, indicating effective reversal of synaptopathy.

Funder: This research was funded by a Nathalie Rose Barr award (NRB110) from the International Spinal Research Trust, and support from Medical Research Council (MR/R004544/1 & MR/R004463/1), NWO (013-16-002), Czech Ministry of Education (CZ.02.1.01/0.0./0.0/15_003/0000419), ERA-NET NEURON AxonRepair, Christopher and Dana Reeve Foundation, International Foundation for Research in Paraplegia, Hersenstichting Nederland., Adeno-associated viral vectors are widely used as vehicles for gene transfer to the nervous system. The promoter and viral vector serotype are two key factors that determine the expression dynamics of the transgene. A previous comparative study has demonstrated that AAV1 displays efficient transduction of layer V corticospinal neurons, but the optimal promoter for transgene expression in corticospinal neurons has not been determined yet. In this paper, we report a side-by-side comparison between four commonly used promoters: the short CMV early enhancer/chicken β actin (sCAG), human cytomegalovirus (hCMV), mouse phosphoglycerate kinase (mPGK) and human synapsin (hSYN) promoter. Reporter constructs with each of these promoters were packaged in AAV1, and were injected in the sensorimotor cortex of rats and mice in order to transduce the corticospinal tract. Transgene expression levels and the cellular transduction profile were examined after 6 weeks. The AAV1 vectors harbouring the hCMV and sCAG promoters resulted in transgene expression in neurons, astrocytes and oligodendrocytes. The mPGK and hSYN promoters directed the strongest transgene expression. The mPGK promoter did drive expression in cortical neurons and oligodendrocytes, while transduction with AAV harbouring the hSYN promoter resulted in neuron-specific expression, including perineuronal net expressing interneurons and layer V corticospinal neurons. This promoter comparison study contributes to improve transgene delivery into the brain and spinal cord. The optimized transduction of the corticospinal tract will be beneficial for spinal cord injury research.

Wolfram syndrome (WS) is a monogenic progressive neurodegenerative disease and is characterized by various neurological symptoms, such as optic nerve atrophy, loss of vision, cognitive decline, memory impairment, and learning difficulties. GLP1 receptor agonist liraglutide and BDNF mimetic 7,8-dihydroxyflavone (7,8-DHF) have had protective effect to visual pathway and to learning and memory in different rat models of neurodegenerative disorders. Although synergistic co-treatment effect has not been reported before and therefore the aim of the current study was to investigate liraglutide, 7,8-DHF and most importantly for the first time their co-treatment effect on degenerative processes in WS rat model. We took 9 months old WS rats and their wild-type (WT) control animals and treated them daily with liraglutide, 7,8-DHF or with the combination of liraglutide and 7,8-DHF up to the age of 12.5 months (n = 47, 5–8 per group). We found that liraglutide, 7,8-DHF and their co-treatment all prevented lateral ventricle enlargement, improved learning in Morris Water maze, reduced neuronal inflammation, delayed the progression of optic nerve atrophy, had remyelinating effect on optic nerve and thereby improved visual acuity in WS rats compared to WT controls. Thus, the use of the liraglutide, 7,8-DHF and their co-treatment could potentially be used as a therapeutic intervention to induce neuroprotection or even neuronal regeneration.

Endothelial cells (ECs) have gained an increased scientific focus since they were reported to provide guidance for Schwann cells and subsequently following axons after nerve injuries. However, previous protocols for the isolation of nerve-derived ECs from human nerves are ineffective regarding time and yield. Therefore, we established a novel and efficient protocol for the isolation of ECs from human peripheral nerves by means of immunomagnetic CD31-antibody conjugated Dynabeads and assessed the purity of the isolated cells. The easy-to-follow and time-effective isolation method allows the isolation of > 95% pure ECs. The isolated ECs were shown to express highly specific EC marker proteins and revealed functional properties by formation of CD31 and VE-cadherin positive adherens junctions, as well as ZO-1 positive tight-junctions. Moreover, the formation of capillary EC-tubes was observed in-vitro. The novel protocol for the isolation of human nerve-derived ECs allows and simplifies the usage of ECs in research of the human blood-nerve-barrier and peripheral nerve regeneration. Additionally, a potential experimental application of patient-derived nerve ECs in the in-vitro vascularization of artificial nerve grafts is feasible.

Hippocampal atrophy and cognitive decline are common sequelae of many neurodegenerative disorders, including stroke. To determine whether cognitive decline can be ameliorated by exercise-induced neurogenesis, C57BL/6 mice in which a unilateral hippocampal injury had been induced by injecting the vasoconstrictor endothelin-1 into their right hippocampus, were run voluntarily for 21 days on a running-wheel. We found the severe deficits in spatial learning, as detected by active place-avoidance task, following injury were almost completely restored in animals that ran whereas those that did not run showed no improvement. We show the increase in neurogenesis found in both the injured and contralateral hippocampi following running was responsible for the restoration of learning since bilateral ablation of newborn doublecortin (DCX)-positive neurons abrogated the cognitive improvement, whereas unilateral ablations of DCX-positive neurons did not prevent recovery, demonstrating that elevated neurogenesis in either the damaged or intact hippocampus is sufficient to reverse hippocampal injury-induced deficits.

Ultrasound-guided platelet-rich plasma (PRP) injection is able to make up for the limitations of applying a single growth factor. The goal of this study was to investigate the effects of serial ultrasound-guided PRP injections of the appropriate concentration on the treatment of sciatic nerve crush injury, and explore the value of multimodality ultrasound techniques in evaluating the prognosis of crushed peripheral nerve. In vitro, optimal concentration of PRP (from 150%, 250%, 450%, and 650%) was screened due for its maximal effect on proliferation and neurotrophic function of Schwann cells (SCs). In vivo, ninety rabbits were equally and randomly divided into normal control, model, PRP-2.5×, PRP-4.5×, and PRP-6.5× groups. The neurological function and electrophysiological recovery evaluation, and the comparison of the multimodality ultrasound evaluation with the histological results of sciatic nerve crush injury were performed to investigate the regenerative effects of PRP at different concentrations on the sciatic nerve crush injury. Our results showed that the PRP with a 4.5-fold concentration of whole blood platelets could significantly stimulate the proliferation and secretion of SCs and nerve repair. The changes in stiffness and blood perfusion were positively correlated with the collagen area percentage and VEGF expression in the injured nerve, respectively. Thus, serial ultrasound-guided PRP injections at an appropriate concentration accelerates the recovery of axonal function. Multimodality ultrasound techniques provide a clinical reference for prognosis by allowing the stiffness and microcirculation perfusion of crush-injured peripheral nerves to be quantitatively evaluated.

Nerve-derived human Schwann cell (SC) cultures are irreplaceable models for basic and translational research but their use can be limited due to the risk of fibroblast overgrowth. Fibroblasts are an ill-defined population consisting of highly proliferative cells that, contrary to human SCs, do not undergo senescence in culture. We initiated this study by performing an exhaustive immunological and functional characterization of adult nerve-derived human SCs and fibroblasts to reveal their properties and optimize a protocol of magnetic-activated cell sorting (MACS) to separate them effectively both as viable and biologically competent cells. We next used immunofluorescence microscopy imaging, flow cytometry analysis and next generation RNA sequencing (RNA-seq) to unambiguously characterize the post-MACS cell products. High resolution transcriptome profiling revealed the identity of key lineage-specific transcripts and the clearly distinct neural crest and mesenchymal origin of human SCs and fibroblasts, respectively. Our analysis underscored a progenitor- or stem cell-like molecular phenotype in SCs and fibroblasts and the heterogeneity of the fibroblast populations. In addition, pathway analysis of RNA-seq data highlighted putative bidirectional networks of fibroblast-to-SC signaling that predict a complementary, yet seemingly independent contribution of SCs and fibroblasts to nerve regeneration. In sum, combining MACS with immunochemical and transcriptomics approaches provides an ideal workflow to exhaustively assess the identity, the stage of differentiation and functional features of highly purified cells from human peripheral nerve tissues. Fil: Peng, Kaiwen. Indiana University. School of Medicine; Estados Unidos. Nanfang Hospital; China Fil: Sant, David. University of Utah; Estados Unidos. Miami University. School of Medicine; Estados Unidos Fil: Andersen, Natalia Denise. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Miami University. School of Medicine; Estados Unidos Fil: Silvera, Risset. Miami University. School of Medicine; Estados Unidos Fil: Camarena, Vladimir. Miami University. School of Medicine; Estados Unidos Fil: Piñero, Gonzalo Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentina. Miami University. School of Medicine; Estados Unidos Fil: Graham, Regina. Miami University. School of Medicine; Estados Unidos Fil: Khan, Aisha. Miami University. School of Medicine; Estados Unidos Fil: Xu, Xiao Ming. Indiana University. School of Medicine; Estados Unidos Fil: Wang, Gaofeng. Miami University. School of Medicine; Estados Unidos Fil: Monje, Paula. Indiana University. School of Medicine; Estados Unidos. Miami University. School of Medicine; Estados Unidos

Deep brain stimulation (DBS) has been tentatively explored to promote motor recovery after stroke. Stroke could transiently activate endogenous self-repair processes, including neurogenesis in the subventricular zone (SVZ). In this regard, it is of considerable clinical interest to study whether DBS of the lateral cerebellar nucleus (LCN) could promote neurogenesis in the SVZ for functional recovery after stroke. In the present study, rats were trained on the pasta matrix reaching task and the ladder rung walking task before surgery. And then an electrode was implanted in the LCN following cortical ischemia induced by endothelin-1 injection. After 1 week of recovery, LCN DBS coupled with motor training for two weeks promoted motor function recovery, and reduced the infarct volumes post-ischemia. LCN DBS augmented poststroke neurogenetic responses, characterized by proliferation of neural progenitor cells (NPCs) and neuroblasts in the SVZ and subsequent differentiation into neurons in the ischemic penumbra at 21 days poststroke. DBS with the same stimulus parameters at 1 month after ischemia could also increase nascent neuroblasts in the SVZ and newly matured neurons in the perilesional cortex at 42 days poststroke. These results suggest that LCN DBS promotes endogenous neurogenesis for neurorestoration after cortical ischemia.

International audience; Different types of carbon materials are biocompatible with neural cells and can promote maturation. The mechanism of this effect is not clear. Here we have tested the capacity of a carbon material composed of amorphous sp 3 carbon backbone, embedded with a percolating network of sp 2 carbon domains to sustain neuronal cultures. We found that cortical neurons survive and develop faster on this novel carbon material. After 3 days in culture, there is a precocious increase in the frequency of neuronal activity and in the expression of maturation marker KCC2 on carbon films as compared to a commonly used glass surface. Accelerated development is accompanied by a dramatic increase in neuronal dendrite arborization. The mechanism for the precocious maturation involves the activation of intracellular calcium oscillations by the carbon material already after 1 day in culture. Carbon-induced oscillations are independent of network activity and reflect intrinsic spontaneous activation of developing neurons. Thus, these results reveal a novel mechanism for carbon material-induced neuronal survival and maturation. Brain trauma as well as neurodegenerative diseases are the leading cause of irreversible disability and low quality of life in the elderly population 1. A way to combat neurodegeneration is to promote reparation of neuronal networks, rewiring of neuronal connections, and eventual restoration or substitution of the lost functionality 2. One putative therapeutic avenue is providing scaffolds-special materials that support targeted differentiation of neuronal stem cells and neurite outgrowth of regenerating neurons. Carbon-derived materials possess numerous properties that make them usable as scaffolds 3. Carbon nanotubes (CNTs) and graphene are among the most studied carbon materials for biological applications. These materials enhance neuronal stem cell differentiation 4-6 , as well as promote neuronal survival, neuronal activity, and neuronal process outgrowth 7-13. Neurons cultured on CNTs have increased levels of neuronal K +-Cl − cotransporter KCC2, a key component in the functional maturation of inhibitory synaptic 14 and glutamatergic 15-17 transmission. Downregulation of this protein is also implicated in reactive plasticity following brain trauma 18. CNTs have been suggested to improve the electrical responsiveness of neurons by facilitating local electronic shortcuts between somas and dendrites 19. The ability of CNTs to form tight contacts with neurons is beneficial for neuron-electrode interfaces 20-24. 3D gra-phene substrates support growth and differentiation of neurons 25-27 that in combination with anti-inflammatory properties 28,29 makes graphene a next-generation neuronal tissue scaffold. Despite the importance of novel carbon materials for future engineering, we do not fully understand the mechanisms underlining the trophic action of carbon scaffolds. In this work, we propose a novel mechanism by which a new type of sputtered carbon material accelerates neuronal maturation. The carbon film material consists of conducting nanoscale sp 2 carbon islands embedded in a diamond-like sp 3 carbon matrix. We demonstrate OPEN

Upon severe head injury (HI), blood vessels of the meninges and brain parenchyma are inevitably damaged. While limited vascular regeneration of the injured brain has been studied extensively, our understanding of meningeal vascular regeneration following head injury is quite limited. Here, we identify key pathways governing meningeal vascular regeneration following HI. Rapid and complete vascular regeneration in the meninges is predominantly driven by VEGFR2 signaling. Substantial increase of VEGFR2 is observed in both human patients and mouse models of HI, and endothelial cell-specific deletion of Vegfr2 in the latter inhibits meningeal vascular regeneration. We further identify the facilitating, stabilizing and arresting roles of Tie2, PDGFRβ and Dll4 signaling, respectively, in meningeal vascular regeneration. Prolonged inhibition of this angiogenic process following HI compromises immunological and stromal integrity of the injured meninges. These findings establish a molecular framework for meningeal vascular regeneration after HI, and may guide development of wound healing therapeutics., Severe head injury results in critical damage of blood vessels of the meninges and brain parenchyma. Here, the authors describe key pathways governing meningeal vascular regeneration following head injury, characterizing the differential roles of VEGFR2, Tie2, Dll4 and PDGFRβ signaling.

Adult zebrafish have the ability to regenerate cells of the central nervous system. However, few neuronal regeneration studies in adult zebrafish addressed their ability to regenerate specific types of neurons following cell specific ablation. We show here that treatment of transgenic Tg(dat:CFP-NTR) adult zebrafish with the prodrug metronidazole (Mtz) according to our administration regimen predominantly ablates dopamine (DA) neurons within the olfactory bulb (OB) of adult fish. Loss of DA neurons was accompanied by an impaired olfaction phenotype, as early as 1-week post-treatment, in which fish were unable to sense the presence of the repulsive stimulus cadaverine. The olfactory impairment was reversed within 45 days and coincided with the recovery of DA neuron counts in the OB. A multi-label pulse-chase analysis with BrdU and EdU over the first seventeen days-post Mtz exposure showed that newly formed DA neurons were recruited within the first nine days following exposure and led to functional and morphological recovery of the OB.

Although autologous nerve grafting is widely accepted as the gold standard treatment for segmental nerve defects, harvesting autologous nerves is highly invasive and leads to functional loss of the ablated part. In response, artificial nerve conduits made of artificial materials have been reported, but the efficacy of the nerve regeneration still needs improvement. The purpose of this study is to investigate the efficacy and mechanism of the Bio three-dimensional (3D) conduit composed of xeno-free human induced pluripotent stem cell–derived mesenchymal stem cells (iMSCs). The 5-mm nerve gap of the sciatic nerve in immunodeficient rats was bridged with the Bio 3D conduit or silicone tube. Functional and histological recovery were assessed at 8 weeks after surgery. The regenerated nerve in the Bio 3D group was significantly superior to that in the silicone group based on morphology, kinematics, electrophysiology, and wet muscle weight. Gene expression analyses demonstrated neurotrophic and angiogenic factors. Macroscopic observation revealed neovascularization both inside and on the surface of the Bio 3D conduit. Upon their subcutaneous implantation, iMSCs could induce angiogenesis. The Bio 3D conduit fabricated from iMSCs are an effective strategy for nerve regeneration in animal model. This technology will be useful in future clinical situations.

The neuropathological hallmarks of Parkinson’s disease include preferential vulnerability of dopaminergic neurons of the substantia nigra pars compacta, and accumulation of intraneuronal protein inclusions known as Lewy bodies. These inclusions contain, among other proteins, aggregated alpha-synuclein and histone deacetylase 6 (HDAC6). In our study we found that selective inhibition of HDAC6 activity by Tubastatin A has protective effects in a rat model of Parkinson’s disease. We provide evidence that this protection may be due to the activation of chaperone-mediated autophagy through the up-regulation of key members of this pathway. Moreover, Tubastatin A significantly inhibited the expression of a toxic form of alpha-synuclein that is phosphorylated at serine position 129. Tubastatin A treatment also permitted to partially modulate neuroinflammation. Taken together, our study highlights the neuroprotective effects of Tubastatin A in a rat model of Parkinson’s disease and provides mechanistic insight in Tubastatin A-mediated protection against alpha-synuclein toxicity and substantia nigra degeneration. These findings are of potential therapeutic value in Parkinson’s disease and other synucleinopathies.

Since Schwann cells (SCs) support axonal growth at development as well as after peripheral nerve injury (PNI), developing SCs might be able to promote axon regeneration after PNI. The purpose of the current study was to elucidate the capability of developing SCs to induce axon regeneration after PNI. SC precursors (SCPs), immature SCs (ISCs), repair SCs (RSCs) from injured nerves, and non-RSCs from intact nerves were tested by grafting into acellular region of rat sciatic nerve with crush injury. Both of developing SCs completely failed to support axon regeneration, whereas both of mature SCs, especially RSCs, induced axon regeneration. Further, RSCs but not SCPs promoted neurite outgrowth of adult dorsal root ganglion neurons. Transcriptome analysis revealed that the gene expression profiles were distinctly different between RSCs and SCPs. These findings indicate that developing SCs are markedly different from mature SCs in terms of functional and molecular aspects and that RSC is a viable candidate for regenerative cell therapy for PNI.

The generation of human oligodendrocyte progenitor cells (OPCs) may be therapeutically valuable for human demyelinating diseases such as multiple sclerosis. Here, we report the direct reprogramming of human somatic cells into expandable induced OPCs (iOPCs) using a combination of OCT4 and a small molecule cocktail. This method enables generation of A2B5+ (an early marker for OPCs) iOPCs within 2 weeks retaining the ability to differentiate into MBP-positive mature oligodendrocytes. RNA-seq analysis revealed that the transcriptome of O4+ iOPCs was similar to that of O4+ OPCs and ChIP-seq analysis revealed that putative OCT4-binding regions were detected in the regulatory elements of CNS development-related genes. Notably, engrafted iOPCs remyelinated the brains of adult shiverer mice and experimental autoimmune encephalomyelitis mice with MOG-induced 14 weeks after transplantation. In conclusion, our study may contribute to the development of therapeutic approaches for neurological disorders, as well as facilitate the understanding of the molecular mechanisms underlying glial development.

Emerging studies suggest the application of self-regulation learning (SRL) to improve generalization abilities in poststroke patients. SRL has been proposed to have an added effect on computer-aided cognitive training (CACT). This study aimed to examine the efficacy of an intervention combining computer-aided SRL (CA-SRL) training and CACT for generalization abilities and cognitive function in patients with poststroke cognitive impairment (PSCI). A total of 75 patients recruited from a rehabilitation centre were randomly assigned to a CA-SRL group, demonstration learning (DL) group and traditional learning (TL) group. Finally, 72 patients were included in the analysis. Over 3 weeks, the patients in these three groups underwent CA-SRL or DL training combined with cognitive training. After the intervention, all outcomes significantly improved (P P P = 0.002) after adjusting for education level and Lawton Instrumental ADL Scale score. In general, the combination of CA-SRL and CACT is effective for PSCI patients and has a better effect on promoting skill generalization from cognitive gains than traditional training.

During injured tissue regeneration, the extracellular matrix plays a key role in controlling and coordinating various cellular events by binding and releasing secreted proteins in addition to promoting cell adhesion. Herein, we develop a cell-adhesive fiber-forming peptide that mimics the jigsaw-shaped hydrophobic surface in the dovetail-packing motif of glycophorin A as an artificial extracellular matrix for regenerative therapy. We show that the jigsaw-shaped self-assembling peptide forms several-micrometer-long supramolecular nanofibers through a helix-to-strand transition to afford a hydrogel under physiological conditions and disperses homogeneously in the hydrogel. The molecular- and macro-scale supramolecular properties of the jigsaw-shaped self-assembling peptide hydrogel allow efficient incorporation and sustained release of vascular endothelial growth factor, and demonstrate cell transplantation-free regenerative therapeutic effects in a subacute-chronic phase mouse stroke model. This research highlights a therapeutic strategy for injured tissue regeneration using the jigsaw-shaped self-assembling peptide supramolecular hydrogel., The extracellular matrix contributes to tissue regeneration by binding and releasing growth factors. Here the authors present the jigsaw-shaped self-assembling peptide JigSAP as an artificial ECM and show that VEGF-JigSAP has therapeutic effects on the subacute-chronic phase of brain stroke.

The hippocampus is a fundamental structure of the brain that plays an important role in neurodevelopment and is very sensitive to hypoxia–ischemia (HI). The purpose of this study was to investigate the effects of sildenafil on neonatal hippocampal brain injuries resulting from HI, and on neuronal development in this context. HI was induced in male Long–Evans rat pups at postnatal day 10 (P10) by a left common carotid ligation followed by a 2-h exposure to 8% oxygen. Rat pups were randomized to vehicle or sildenafil given orally twice daily for 7 days starting 12 h after HI. Hematoxylin and eosin staining was performed at P30 to measure the surface of the hippocampus; immunohistochemistry was performed to stain neurons, oligodendrocytes, and glial cells in the hippocampus. Western blots of the hippocampus were performed at P12, P17, and P30 to study the expression of neuronal markers and mTOR pathway. HI caused significant hippocampal atrophy and a significant reduction of the number of mature neurons, and induced reactive astrocytosis and microgliosis in the hippocampus. HI increased apoptosis and caused significant dysregulation of the normal neuronal development program. Treatment with sildenafil preserved the gross morphology of the hippocampus, reverted the number of mature neurons to levels comparable to sham rats, significantly increased both the immature and mature oligodendrocytes, and significantly reduced the number of microglia and astrocytes. Sildenafil also decreased apoptosis and reestablished the normal progression of post-natal neuronal development. The PI3K/Akt/mTOR pathway, whose activity was decreased after HI in the hippocampus, and restored after sildenafil treatment, may be involved. Sildenafil may have both neuroprotective and neurorestorative properties in the neonatal hippocampus following HI.

The development of outcome measures that can track the recovery of reinnervated muscle would benefit the clinical investigation of new therapies which hope to enhance peripheral nerve repair. The primary objective of this study was to assess the validity of volumetric Magnetic Resonance Imaging (MRI) as an outcome measure of muscle reinnervation by testing its reproducibility, responsiveness and relationship with clinical indices of muscular function. Over a 3-year period 25 patients who underwent nerve transfer to reinnervate elbow flexor muscles were assessed using intramuscular electromyography (EMG) and MRI (median post-operative assessment time of 258 days, ranging from 86 days pre-operatively to 1698 days post- operatively). Muscle power (Medical Research Council (MRC) grade) and Stanmore Percentage of Normal Elbow Assessment (SPONEA) assessment was also recorded for all patients. Sub-analysis of peak volitional force (PVF), muscular fatigue and co-contraction was performed in those patients with MRC > 3. The responsiveness of each parameter was compared using Pearson or Spearman correlation. A Hierarchical Gaussian Process (HGP) was implemented to determine the ability of volumetric MRI measurements to predict the recovery of muscular function. Reinnervated muscle volume per unit Body Mass Index (BMI) demonstrated good responsiveness (R2 = 0.73, p 2 = 0.63, p = 0.02) and muscle fatigue (R2 = 0.64, p = 0.04). In summary, volumetric MRI analysis of reinnervated muscle is highly reproducible, responsive to post-operative time and demonstrates correlation with clinical indices of muscle function. This encourages the view that volumetric MRI is a promising outcome measure for muscle reinnervation which will drive advancements in motor recovery therapy.

The treatment of spinal cord injury (SCI) is a complex challenge in regenerative medicine, complicated by the low intrinsic capacity of CNS neurons to regenerate their axons and the heterogeneity in size, shape and extent of human injuries. For example, some contusion injuries do not compromise the dura mater and in such cases implantation of preformed scaffolds or drug delivery systems may cause further damage. Injectable in situ thermosensitive scaffolds are therefore a less invasive alternative. In this study, we report the development of a novel, flowable, thermosensitive, injectable drug delivery system comprising bovine collagen (BC) and fibrinogen (FB) that forms a solid BC/FB gel (Gel) immediately upon exposure to physiological conditions and can be used to deliver reparative drugs, such as the naturally occurring anti-inflammatory, anti-scarring agent Decorin, into adult rat spinal cord lesion sites. In dorsal column lesions of adult rats treated with the Gel + Decorin, cavitation was completely suppressed and instead lesion sites became filled with injury-responsive cells and extracellular matrix materials, including collagen and laminin. Decorin increased the intrinsic potential of dorsal root ganglion neurons (DRGN) by increasing their expression of regeneration associated genes (RAGs), enhanced local axon regeneration/sprouting, as evidenced both histologically and by improved electrophysiological, locomotor and sensory function recovery. These results suggest that this drug formulated, injectable hydrogel has the potential to be further studied and translated into the clinic.

Summary Reprogramming brain-resident glial cells into clinically relevant induced neurons (iNs) is an emerging strategy toward replacing lost neurons and restoring lost brain functions. A fundamental question is now whether iNs can promote functional recovery in pathological contexts. We addressed this question in the context of therapy-resistant mesial temporal lobe epilepsy (MTLE), which is associated with hippocampal seizures and degeneration of hippocampal GABAergic interneurons. Using a MTLE mouse model, we show that retrovirus-driven expression of Ascl1 and Dlx2 in reactive hippocampal glia in situ, or in cortical astroglia grafted in the epileptic hippocampus, causes efficient reprogramming into iNs exhibiting hallmarks of interneurons. These induced interneurons functionally integrate into epileptic networks and establish GABAergic synapses onto dentate granule cells. MTLE mice with GABAergic iNs show a significant reduction in both the number and cumulative duration of spontaneous recurrent hippocampal seizures. Thus glia-to-neuron reprogramming is a potential disease-modifying strategy to reduce seizures in therapy-resistant epilepsy., Graphical abstract, Highlights • Retroviruses target reactive hippocampal glia proliferating in a mouse model of mesial temporal lobe epilepsy • Ascl1 and Dlx2 reprogram reactive glia into GABAergic interneurons in the epileptic hippocampus • Induced interneurons establish GABAergic synapses onto dentate granule cells • Induced interneurons reduce chronic epileptic activity in the hippocampus, Mesial temporal lobe epilepsy belongs to treatment-refractory forms of human epilepsy. Lentini et al. show that reactive glia proliferating in the epileptic hippocampus can be reprogrammed into GABAergic induced neurons that reduce chronic seizure activity. This study uncovers glia-to-neuron reprogramming as a potential disease-modifying strategy to reduce intractable seizures.

Electrical stimulation of the cervical spinal cord is gaining traction as a therapy following spinal cord injury; however, it is difficult to target the cervical motor region in a rodent using a non-penetrating stimulus compared with direct placement of intraspinal wire electrodes. Penetrating wire electrodes have been explored in rodent and pig models and, while they have proven beneficial in the injured spinal cord, the negative aspects of spinal parenchymal penetration (e.g., gliosis, neural tissue damage, and obdurate inflammation) are of concern when considering therapeutic potential. We therefore designed a novel approach for epidural stimulation of the rat spinal cord using a wireless stimulation system and ventral electrode array. Our approach allowed for preservation of mobility following surgery and was suitable for long term stimulation strategies in awake, freely functioning animals. Further, electrophysiology mapping of the ventral spinal cord revealed the ventral approach was suitable to target muscle groups of the rat forelimb and, at a single electrode lead position, different stimulation protocols could be applied to achieve unique activation patterns of the muscles of the forelimb.

Successful cell therapy for Parkinson’s disease (PD) requires large numbers of homogeneous ventral mesencephalic dopaminergic (vmDA) precursors. Enrichment of vmDA precursors via cell sorting is required to ensure high safety and efficacy of the cell therapy. Here, using LMX1A-eGFP knock-in reporter human embryonic stem cells, we discovered a novel surface antigen, trophoblast glycoprotein (TPBG), which was preferentially expressed in vmDA precursors. TPBG-targeted cell sorting enriched FOXA2+LMX1A+ vmDA precursors and helped attain efficient behavioral recovery of rodent PD models with increased numbers of TH+, NURR1+, and PITX3+ vmDA neurons in the grafts. Additionally, fewer proliferating cells were detected in TPBG+ cell-derived grafts than in TPBG− cell-derived grafts. Our approach is an efficient way to obtain enriched bona fide vmDA precursors, which could open a new avenue for effective PD treatment.

Peripheral Nerve Injury (PNI) represents a major clinical and economic burden. Despite the ability of peripheral neurons to regenerate their axons after an injury, patients are often left with motor and/or sensory disability and may develop chronic pain. Successful regeneration and target organ reinnervation require comprehensive transcriptional changes in both injured neurons and support cells located at the site of injury. The expression of most of the genes required for axon growth and guidance and for synapsis formation is repressed by a single master transcriptional regulator, the Repressor Element 1 Silencing Transcription factor (REST). Sustained increase of REST levels after injury inhibits axon regeneration and leads to chronic pain. As targeting of transcription factors is challenging, we tested whether modulation of REST activity could be achieved through knockdown of carboxy-terminal domain small phosphatase 1 (CTDSP1), the enzyme that stabilizes REST by preventing its targeting to the proteasome. To test whether knockdown of CTDSP1 promotes neurotrophic factor expression in both support cells located at the site of injury and in peripheral neurons, we transfected mesenchymal progenitor cells (MPCs), a type of support cells that are present at high concentrations at the site of injury, and dorsal root ganglion (DRG) neurons with REST or CTDSP1 specific siRNA. We quantified neurotrophic factor expression by RT-qPCR and Western blot, and brain-derived neurotrophic factor (BDNF) release in the cell culture medium by ELISA, and we measured neurite outgrowth of DRG neurons in culture. Our results show that CTDSP1 knockdown promotes neurotrophic factor expression in both DRG neurons and the support cells MPCs, and promotes DRG neuron regeneration. Therapeutics targeting CTDSP1 activity may, therefore, represent a novel epigenetic strategy to promote peripheral nerve regeneration after PNI by promoting the regenerative program repressed by injury-induced increased levels of REST in both neurons and support cells.

Prokineticin-2 (Prok2) is an important secreted protein likely involved in the pathogenesis of several acute and chronic neurological diseases through currently unidentified regulatory mechanisms. The initial mechanical injury of neurons by traumatic brain injury triggers multiple secondary responses including various cell death programs. One of these is ferroptosis, which is associated with dysregulation of iron and thiols and culminates in fatal lipid peroxidation. Here, we explore the regulatory role of Prok2 in neuronal ferroptosis in vitro and in vivo. We show that Prok2 prevents neuronal cell death by suppressing the biosynthesis of lipid peroxidation substrates, arachidonic acid-phospholipids, via accelerated F-box only protein 10 (Fbxo10)-driven ubiquitination, degradation of long-chain-fatty-acid-CoA ligase 4 (Acsl4), and inhibition of lipid peroxidation. Mice injected with adeno-associated virus-Prok2 before controlled cortical impact injury show reduced neuronal degeneration and improved motor and cognitive functions, which could be inhibited by Fbxo10 knockdown. Our study shows that Prok2 mediates neuronal cell deaths in traumatic brain injury via ferroptosis., Prokineticin-2 (Prok2) is a secreted protein involved in many physiological processes. Here, the authors show that Prok2 prevents neuronal cell ferroptosis after traumatic brain injury and its administration before cortical injury reduces neuronal degeneration, and motor and cognitive impairments.

Recovery after stroke is thought to be mediated by adaptive circuit plasticity, whereby surviving neurons assume the roles of those that died. However, definitive longitudinal evidence of neurons changing their response selectivity after stroke is lacking. We sought to directly test whether such functional “remapping” occurs within mouse primary somatosensory cortex after a stroke that destroys the C1 barrel. Using in vivo calcium imaging to longitudinally record sensory-evoked activity under light anesthesia, we did not find any increase in the number of C1 whisker-responsive neurons in the adjacent, spared D3 barrel after stroke. To promote plasticity after stroke, we also plucked all whiskers except C1 (forced use therapy). This led to an increase in the reliability of sensory-evoked responses in C1 whisker-responsive neurons but did not increase the number of C1 whisker-responsive neurons in spared surround barrels over baseline levels. Our results argue against remapping of functionality after barrel cortex stroke, but support a circuit-based mechanism for how rehabilitation may improve recovery., Definitive evidence for functional remapping after stroke remains lacking. Here, the authors performed in vivo intrinsic signal imaging and two-photon calcium imaging of sensory-evoked responses before and after photothrombotic stroke and found no evidence of remapping of lost functionalities to new circuits in peri-infarct cortex.

Atr is a serine/threonine kinase, known to sense single-stranded DNA breaks and activate the DNA damage checkpoint by phosphorylating Chek1, which inhibits Cdc25, causing cell cycle arrest. This pathway has not been implicated in neuroregeneration. We show that in Drosophila sensory neurons removing Atr or Chek1, or overexpressing Cdc25 promotes regeneration, whereas Atr or Chek1 overexpression, or Cdc25 knockdown impedes regeneration. Inhibiting the Atr-associated checkpoint complex in neurons promotes regeneration and improves synapse/behavioral recovery after CNS injury. Independent of DNA damage, Atr responds to the mechanical stimulus elicited during regeneration, via the mechanosensitive ion channel Piezo and its downstream NO signaling. Sensory neuron-specific knockout of Atr in adult mice, or pharmacological inhibition of Atr-Chek1 in mammalian neurons in vitro and in flies in vivo enhances regeneration. Our findings reveal the Piezo-Atr-Chek1-Cdc25 axis as an evolutionarily conserved inhibitory mechanism for regeneration, and identify potential therapeutic targets for treating nervous system trauma., The Atr-Check1 pathway is involved in cell cycle and the DNA damage response. Here, the authors show that the Atr-Check1 pathway can inhibit axon regeneration in response to Piezo-mediated mechanosensation, affecting functional recovery.

High-resolution neurosonography (HRNS) has become a major imaging modality in assessment of peripheral nerve trauma in the recent years. However, the vascular changes of traumatic lesions have not been quantitatively assessed in HRNS. Here, we describe the vascular-ratio, a novel HRNS-based quantitative parameter for the assessment of intraneural vascular alterations in patients with nerve lesions. N = 9 patients suffering from peripheral nerve trauma were examined clinically, electrophysiologically and with HRNS (SonoSite Exporte, Fuji). Image analyses using Fiji included determination of the established fascicular ratio (FR), the cross-section ratio (CSR), and as an extension, the calculation of a vascular ratio (VR) of the healthy versus damaged nerve and a muscle perfusion ratio (MPR) in comparison to a healthy control group. The mean VR in the healthy part of the affected nerve (14.14%) differed significantly (p

As the application of graphene nanomaterials gets increasingly attractive in the field of tissue engineering and regenerative medicine, the long-term evaluation is necessary and urgent as to their biocompatibility and regenerative capacity in different tissue injuries, such as nerve, bone, and heart. However, it still remains controversial about the potential biological effects of graphene on neuronal activity, especially after severe nerve injuries. In this study, we establish a lengthy peripheral nerve defect rat model and investigate the potential toxicity of layered graphene-loaded polycaprolactone scaffold after implantation during 18 months in vivo. In addition, we further identify possible biologically regenerative effects of this scaffold on myelination, axonal outgrowth, and locomotor function recovery. It is confirmed that graphene-based nanomaterials exert negligible toxicity and repair large nerve defects by dual regulation of Schwann cells and astroglia in the central and peripheral nervous systems. The findings enlighten the future of graphene nanomaterial as a key type of biomaterials for clinical translation in neuronal regeneration.

Nerve wrapping improves neurorrhaphy outcomes in case of peripheral nerve injuries (PNIs). The aim of this preclinical study was to assess the efficacy of two novel biodegradable wraps made of a synthetic 1% oxidized polyvinyl alcohol (OxPVA) and a natural leukocyte-fibrin-platelet membrane (LFPm) versus the commercial product NeuraWrap. After rats sciatic nerve transection and neurorrhaphy, the wraps were implanted and compared for functional outcome, by sciatic function index assessment; structural characteristics, by histological/immunohistochemical analysis; ultrastructural features, by transmission electron microscopy. Moreover, a morphometric study was also performed and collagen distribution was observed by Second Harmonic Generation microscopy. After 12 weeks from implantation, all wraps assured nerve function recovery; no scar tissue/neuromas were visible at dissection. LFPm wraps were completely resorbed, while residues of OxPVA and NeuraWrap were observed. In all groups, biocompatibility was confirmed by the absence of significant inflammatory infiltrate. According to histological/immunohistochemical analysis and morphometric findings, OxPVA and LFPm wraps were both effective in preserving nerve integrity. These results assess that bioengineered OxPVA and LFPm wraps successfully guarantee favorable lesion recovery after PNI/neurorrhaphy and, in future, may be considered an interesting alternative to the commercial NeuraWrap.

During the progression of the neurodegenerative process, mitochondria participates in several intercellular signaling pathways. Voltage-dependent anion-selective channel 1 (VDAC1) is a mitochondrial porin involved in the cellular metabolism and apoptosis intrinsic pathway in many neuropathological processes. In spinal cord injury (SCI), after the primary cell death, a secondary response that comprises the release of pro-inflammatory molecules triggers apoptosis, inflammation, and demyelination, often leading to the loss of motor functions. Here, we investigated the functional role of VDAC1 in the neurodegeneration triggered by SCI. We first determined that in vitro targeted ablation of VDAC1 by specific morpholino antisense nucleotides (MOs) clearly promotes neurite retraction, whereas a pharmacological blocker of VDAC1 oligomerization (4, 4′-diisothiocyanatostilbene-2, 2′-disulfonic acid, DIDS), does not cause this effect. We next determined that, after SCI, VDAC1 undergoes conformational changes, including oligomerization and N-terminal exposition, which are important steps in the triggering of apoptotic signaling. Considering this, we investigated the effects of DIDS in vivo application after SCI. Interestingly, blockade of VDAC1 oligomerization decreases the number of apoptotic cells without interfering in the neuroinflammatory response. DIDS attenuates the massive oligodendrocyte cell death, subserving undisputable motor function recovery. Taken together, our results suggest that the prevention of VDAC1 oligomerization might be beneficial for the clinical treatment of SCI.

Knockout of phosphatase and tensin homolog (PTEN−/−) is neuroprotective and promotes axon regeneration in mature neurons. Elevation of mTOR activity in injured neurons has been proposed as the primary underlying mechanism. Here we demonstrate that PTEN−/− also abrogates the inhibitory activity of GSK3 on collapsin response mediator protein 2 (CRMP2) in retinal ganglion cell (RGC) axons. Moreover, maintenance of GSK3 activity in Gsk3S/A knockin mice significantly compromised PTEN−/−-mediated optic nerve regeneration as well as the activity of CRMP2, and to a lesser extent, mTOR. These GSK3S/A mediated negative effects on regeneration were rescued by viral expression of constitutively active CRMP2T/A, despite decreased mTOR activation. Gsk3S/A knockin or CRMP2 inhibition also decreased PTEN−/− mediated neurite growth of RGCs in culture and disinhibition towards CNS myelin. Thus, the GSK3/CRMP2 pathway is essential for PTEN−/− mediated axon regeneration. These new mechanistic insights may help to find novel strategies to promote axon regeneration., Loss of the PTEN protein, an event that activates PI3K/AKT signaling, in neurons enables axon regeneration. Now Leibinger et al show in retinal ganglion cells and during optic nerve regeneration in mice, that this is mediated by inactivation of the AKT substrate GSK3, which in turn releases axonal CRMP2 from GSK3-mediatated inhibition.

Traumatic spinal cord injury results in severe and irreversible loss of function. The injury triggers a complex cascade of inflammatory and pathological processes, culminating in formation of a scar. While traditionally referred to as a glial scar, the spinal injury scar in fact comprises multiple cellular and extracellular components. This multidimensional nature should be considered when aiming to understand the role of scarring in limiting tissue repair and recovery. In this Review we discuss recent advances in understanding the composition and phenotypic characteristics of the spinal injury scar, the oversimplification of defining the scar in binary terms as good or bad, and the development of therapeutic approaches to target scar components to enable improved functional outcome after spinal cord injury., The scar formation that occurs following spinal cord injury has properties that are distinct to scars seen in other areas of the CNS, and in other tissues. Here the authors discuss the components of the spinal cord injury scar and how it can have both detrimental and positive roles in relation to recovery.

While axons within the central nervous system (CNS) do not regenerate following injury, those in the peripheral nervous system (PNS) do, although not in a clinically satisfactory manner as only a small proportion of axons exhibit long-distance regeneration. Moreover, functional recovery is hampered by excessive axonal sprouting and aberrant reinnervation of target tissue. In order to investigate the mechanisms governing the regrowth of axons following injury, previous studies have used lesion paradigms of peripheral nerves in rat or mouse models, and reagents or cells have been administered to the lesion site through nerve conduits, aiming to improve early-stage regeneration. Morphological analysis of such in vivo experiments has however been limited by the incompatibility of synthetic nerve conduits with existing tissue-clearing and imaging techniques. We present herein a novel experimental approach that allows high-resolution imaging of individual axons within nerve conduits, together with quantitative assessment of fiber growth. We used a GFP-expressing mouse strain in a lesion model of the sciatic nerve to describe a strategy that combines nerve clearing, chemical treatment of chitosan nerve conduits, and long working distance confocal microscopy with image processing and analysis. This novel experimental setup provides a means of documenting axon growth within the actual conduit during the critical initial stage of regeneration. This will greatly facilitate the development and evaluation of treatment regimens to improve axonal regeneration following nerve damage. ispartof: SCIENTIFIC REPORTS vol:9 issue:1 ispartof: location:England status: published

Cranial nerve injury is disabling for patients, and facial nerve injury is particularly debilitating due to combined functional impairment and disfigurement. The most widely accepted approaches for reconstructing nerve gap injuries involve using sensory nerve grafts to bridge the nerve defect. Prior work on preferential motor reinnervation suggests, however, that motor pathways may preferentially support motoneuron regeneration after nerve injury. The effect of motor versus sensory nerve grafting after facial nerve injury has not been previously investigated. Insights into outcomes of motor versus sensory grafting may improve understanding and clinical treatment of facial nerve paralysis, mitigating facial asymmetry, aberrant reinnervation, and synkinesis. This study examined motor versus sensory grafting of the facial nerve to investigate effect of pathway on regeneration across a 5-mm rodent facial nerve defect. We enrolled 18 rats in 3 cohorts (motor, sensory, and defect) and recorded outcome measures including fiber count/nerve density, muscle endplate reinnervation, compound muscle action potential, and functional whisker twitch analysis. Outcomes were similar for motor versus sensory groups, suggesting similar ability of sensory and motor grafts to support regeneration in a clinically relevant model of facial nerve injury.

Time course, in vivo imaging of brain cells is crucial to fully understand the progression of secondary cellular damage and recovery in murine models of injury. We have combined high-resolution gradient index lens technology with a model of diffuse axonal injury in rodents to enable repeated visualization of fine features of individual cells in three-dimensional space over several weeks. For example, we recorded changes in morphology in the same axons in the external capsule numerous times over 30 to 60 days, before and after induced traumatic brain injury. We observed the expansion of secondary injury and limited recovery of individual axons in this subcortical white matter tract over time. In another application, changes in microglial activation state were visualized in the penumbra region of mice before and after ischemia induced by middle carotid artery occlusion. The ability to collect a series of high-resolution images of cellular features of the same cells pre- and post-injury enables a unique opportunity to study the progression of damage, spontaneous healing, and effects of therapeutics in mouse models of neurodegenerative disease and brain injury.

Despite advancements in human pluripotent stem cells (hPSCs) differentiation protocols to generate appropriate neuronal progenitors suitable for transplantation in Parkinson’s disease, resultant grafts contain low proportions of dopamine neurons. Added to this is the tumorigenic risk associated with the potential presence of incompletely patterned, proliferative cells within grafts. Here, we utilised a hPSC line carrying a FailSafeTM suicide gene (thymidine kinase linked to cyclinD1) to selectively ablate proliferative cells in order to improve safety and purity of neural transplantation in a Parkinsonian model. The engineered FailSafeTM hPSCs demonstrated robust ventral midbrain specification in vitro, capable of forming neural grafts upon transplantation. Activation of the suicide gene within weeks after transplantation, by ganciclovir administration, resulted in significantly smaller grafts without affecting the total yield of dopamine neurons, their capacity to innervate the host brain or reverse motor deficits at six months in a rat Parkinsonian model. Within ganciclovir-treated grafts, other neuronal, glial and non-neural populations (including proliferative cells), were significantly reduced—cell types that may pose adverse or unknown influences on graft and host function. These findings demonstrate the capacity of a suicide gene-based system to improve both the standardisation and safety of hPSC-derived grafts in a rat model of Parkinsonism., Stem cell grafts present a risk of tissue overgrowth/tumors. Here, the authors utilise a human pluripotent stem cell line carrying a FailSafe suicide gene to not only ablate proliferative cells, but through timely gene activation, improve the purity of neural grafts in Parkinsonian rats.

Stroke profoundly disrupts cortical excitability which impedes recovery, but how it affects the function of specific inhibitory interneurons, or subpopulations therein, is poorly understood. Interneurons expressing vasoactive intestinal peptide (VIP) represent an intriguing stroke target because they can regulate cortical excitability through disinhibition. Here we chemogenetically augmented VIP interneuron excitability in a murine model of photothrombotic stroke and show that it enhances somatosensory responses and improves recovery of paw function. Using longitudinal calcium imaging, we discovered that stroke primarily disrupts the fidelity (fraction of responsive trials) and predictability of sensory responses within a subset of highly active VIP neurons. Partial recovery of responses occurred largely within these active neurons and was not accompanied by the recruitment of minimally active neurons. Importantly, chemogenetic stimulation preserved sensory response fidelity and predictability in highly active neurons. These findings provide a new depth of understanding into how stroke and prospective therapies (chemogenetics), can influence subpopulations of inhibitory interneurons., Stroke profoundly disrupts cortical excitability which impedes recovery, but how stroke affects inhibitory interneurons is poorly understood. Here, the authors show that functional impairments after stroke are associated with the disruption of a highly active subpopulation of interneurons expressing vasoactive intestinal peptide (VIP), which could be ameliorated by chemogenetic stimulation.

Transplantation of several types of stem cells (SC) for the treatment of amyotrophic lateral sclerosis (ALS) has been evaluated in numerous Phase I/II clinical trials with inconclusive results. Here, we conducted a meta-analysis to systematically assess the outcome of SC therapy trials which report the evolution of each patient before and after cell administration. In this way, we aimed to determine the effect of the SC intervention despite individual heterogeneity in disease progression. We identified 670 references by electronic search and 90 full-text studies were evaluated according to the eligibility criteria. Eleven studies were included comprising 220 cell-treated patients who received mesenchymal (M) SC (n=152), neural (N) SC (n=57), or mononuclear cells (MNC: CD34, CD117, and CD133 positive cells) (n=11). Our analyses indicate that whereas intrathecal injection of mesenchymal stromal cells appears to have a transient positive effect on clinical progression, as measured by the ALS functional rating score, there was a worsening of respiratory function measured by forced vital capacity after all interventions. Based on current evidence, we conclude that optimal cell product and route of administration need to be determined in properly controlled preclinical models before further advancing into ALS patients. In addition, in-depth understanding of disease mechanisms in subsets of patients will help tailoring SC therapy to specific targets and increase the likelihood of improving outcomes R.S.P. is the recipient of a Talentia Senior grant from the Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades of the Andalusian Government. L.M. is partly supported by the AGING Project for Department of Excellence at the Department of Translational Medicine (DIMET), Università del Piemonte Orientale, Novara, Italy.

Dance is a complex sensorimotor activity with positive effects on physical fitness, cognition, and brain plasticity in the aging population. We explored whether individual levels of cognitive reserve (CR) proxied by education moderate dance intervention (DI)-induced plasticity assessed by resting-state functional connectivity (rs-FC) changes of the sensorimotor network (SMN), and between the dorsal attention network (DAN) and anterior default mode network (aDMN). Our cohort consisted of 99 subjects, randomly assigned to either a DI group who underwent a 6-month intervention (n = 49, Mage = 69.02 ± 5.40) or a control group (n = 50, Mage = 69.37 ± 6.10). Moderation analyses revealed that CR moderated DI-induced increases of the SMN rs-FC with significant changes observed in participants with ≥ 13 years of education (b = .05, t(64) = 3.20, p

Chronic demyelination in the human CNS is characterized by an inhibitory microenvironment that impairs recruitment and differentiation of oligodendrocyte progenitor cells (OPCs) leading to failed remyelination and axonal atrophy. By network-based transcriptomics, we identified sulfatase 2 (Sulf2) mRNA in activated human primary OPCs. Sulf2, an extracellular endosulfatase, modulates the signaling microenvironment by editing the pattern of sulfation on heparan sulfate proteoglycans. We found that Sulf2 was increased in demyelinating lesions in multiple sclerosis and was actively secreted by human OPCs. In experimental demyelination, elevated OPC Sulf1/2 expression directly impaired progenitor recruitment and subsequent generation of oligodendrocytes thereby limiting remyelination. Sulf1/2 potentiates the inhibitory microenvironment by promoting BMP and WNT signaling in OPCs. Importantly, pharmacological sulfatase inhibition using PI-88 accelerated oligodendrocyte recruitment and remyelination by blocking OPC-expressed sulfatases. Our findings define an important inhibitory role of Sulf1/2 and highlight the potential for modulation of the heparanome in the treatment of chronic demyelinating disease., Demyelination results in impairments in oligodendrocyte progenitor cell recruitment. Here the authors identify sulfatase 1/2 as a potential modulator of myelination by modulating the microenvironment around oligodendrocyte progenitor cells.

In the majority of spinal cord injury (SCI) patients, spasticity develops in the subacute phase and chronically persists with muscle hypertonia. Among various pathological conditions underlying spasticity, upregulated expression of 5-HT receptors (5-HTR) on the spinal motor neurons due to 5-HT denervation is considered one of crucial factors for hyperexcitability of the spinal circuit. As a 5-HT signal modulator, selective serotonin re-uptake inhibitors (SSRIs) are ordinarily prescribed for diseases associated with 5-HT in the CNS, and are known for their ability to increase 5-HT levels as well as to desensitize 5-HTR. Here, we hypothesized that early SSRI administration as a preemptive treatment strategy would effectively prevent the onset of spasticity. We used a rat model of contusive SCI and administered escitalopram during the first 4 weeks after injury, which is the period required for spasticity development in rodent models. We performed a swimming test to quantify spastic behaviors and conducted the Hoffman reflex test as well as histological analyses for 5-HT2AR and KCC2 expressions. Four weeks of escitalopram administration suppressed spastic behaviors during the swimming test and reduced the population of spasticity-strong rats. Moreover, the treatment resulted in decreased immunoreactivity of 5-HT2AR in the spinal motor neurons. Result of the H-reflex test and membrane expression of KCC2 were not significantly altered. In summary, early escitalopram administration could prevent the onset of spastic behaviors via regulation of 5-HT system after SCI, but could not modulate exaggerated spinal reflex. Our results suggest a novel application of SSRIs for preventative treatment of spasticity.