Improvement by Human Oligodendrocyte Progenitor Cells of Neurobehavioral Disorders in an Experimental Model of Neonatal Periventricular Leukomalacia

Glial-restricted progenitor cells: a cure for diseased brain?

The central nervous system (CNS) is home to neuronal and glial cells. Traditionally, glia was disregarded as just the structural support across the brain and spinal cord, in striking contrast to neurons, always considered critical players in CNS functioning. In modern times this outdated dogma is continuously repelled by new evidence unravelling the importance of glia in neuronal maintenance and function. Therefore, glia replacement has been considered a potentially powerful therapeutic strategy. Glial progenitors are at the center of this hope, as they are the source of new glial cells. Indeed, sophisticated experimental therapies and exciting clinical trials shed light on the utility of exogenous glia in disease treatment. Therefore, this review article will elaborate on glial-restricted progenitor cells (GRPs), their origin and characteristics, available sources, and adaptation to current therapeutic approaches aimed at various CNS diseases, with particular attention paid to myelin-related disorders with a focus on recent progress and emerging concepts. The landscape of GRP clinical applications is also comprehensively presented, and future perspectives on promising, GRP-based therapeutic strategies for brain and spinal cord diseases are described in detail.

Stem cell-based interventions for the treatment of stroke in newborn infants

BACKGROUND

Perinatal stroke refers to a diverse but specific group of cerebrovascular diseases that occur between 20 weeks of fetal life and 28 days of postnatal life. Acute treatment options for perinatal stroke are limited supportive care, such as controlling hypoglycemia and seizures. Stem cell-based therapies offer a potential therapeutic approach to repair, restore, or regenerate injured brain tissue. Preclinical findings have culminated in ongoing human neonatal studies.

OBJECTIVES

To evaluate the benefits and harms of stem cell-based interventions for the treatment of stroke in newborn infants compared to control (placebo or no treatment) or stem-cell based interventions of a different type or source.

SEARCH METHODS

We searched CENTRAL, PubMed, Embase, and three trials registries in February 2023. We planned to search the reference lists of included studies and relevant systematic reviews for studies not identified by the database searches.

SELECTION CRITERIA

We attempted to include randomized controlled trials, quasi-randomized controlled trials, and cluster trials that evaluated any of the following comparisons. • Stem cell-based interventions (any type) versus control (placebo or no treatment) • Mesenchymal stem/stromal cells (MSCs) of a specifictype (e.g. number of doses or passages) or source (e.g. autologous/allogeneic or bone marrow/cord) versus MSCs of another type or source • Stem cell-based interventions (other than MSCs) of a specific type (e.g. mononuclear cells, oligodendrocyte progenitor cells, neural stem cells, hematopoietic stem cells, or induced pluripotent stem cell-derived cells) or source (e.g. autologous/allogeneic or bone marrow/cord) versus stem cell-based interventions (other than MSCs) of another type or source • MSCs versus stem cell-based interventions other than MSCs We planned to include all types of transplantation regardless of cell source (bone marrow, cord blood, Wharton's jelly, placenta, adipose tissue, peripheral blood), type of graft (autologous or allogeneic), and dose.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were all-cause neonatal mortality, major neurodevelopmental disability, and immune rejection or any serious adverse event. Our secondary outcomes included all-cause mortality prior to first hospital discharge, seizures, adverse effects, and death or major neurodevelopmental disability at 18 to 24 months of age. We planned to use GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified no completed or ongoing randomized trials that met our inclusion criteria. We excluded three studies: two were phase 1 trials, and one included newborn infants with conditions other than stroke (i.e. cerebral ischemia and anemia). Among the three excluded studies, we identified the first phase 1 trial on the use of stem cells for neonatal stroke. It reported that a single intranasal application of bone marrow-derived MSCs in term neonates with a diagnosis of perinatal arterial ischemic stroke (PAIS) was feasible and apparently not associated with severe adverse events. However, the trial included only 10 infants, and follow-up was limited to three months.

AUTHORS' CONCLUSIONS

No evidence is currently available to evaluate the benefits and harms of stem cell-based interventions for treatment of stroke in newborn infants. We identified no ongoing studies. Future clinical trials should focus on standardizing the timing and method of cell delivery and cell processing to optimize the therapeutic potential of stem cell-based interventions and safety profiles. Phase 1 and large animal studies might provide the groundwork for future randomized trials. Outcome measures should include all-cause mortality, major neurodevelopmental disability and immune rejection, and any other serious adverse events.

Oligodendrocyte Progenitor Cell Transplantation Ameliorates Preterm Infant Cerebral White Matter Injury in Rats Model

Background

Cerebral white matter injury (WMI) is the most common brain injury in preterm infants, leading to motor and developmental deficits often accompanied by cognitive impairment. However, there is no effective treatment. One promising approach for treating preterm WMI is cell replacement therapy, in which lost cells can be replaced by exogenous oligodendrocyte progenitor cells (OPCs).

Methods

This study developed a method to differentiate human neural stem cells (hNSCs) into human OPCs (hOPCs). The preterm WMI animal model was established in rats on postnatal day 3, and OLIG2+/NG2+/PDGFRα+/O4+ hOPCs were enriched and transplanted into the corpus callosum on postnatal day 10. Then, histological analysis and electron microscopy were used to detect lesion structure; behavioral assays were performed to detect cognitive function.

Results

Transplanted hOPCs survived and migrated throughout the major white matter tracts. Morphological differentiation of transplanted hOPCs was observed. Histological analysis revealed structural repair of lesioned areas. Re-myelination of the axons in the corpus callosum was confirmed by electron microscopy. The Morris water maze test revealed cognitive function recovery.

Conclusion

Our study showed that exogenous hOPCs could differentiate into CC1+ OLS in the brain of WMI rats, improving their cognitive functions.

Effectiveness of Combinational Treatments for Alzheimer's Disease with Human Neural Stem Cells and Microglial Cells Over-Expressing Functional Genes

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. In AD patients, amyloid-β (Aβ) peptide-mediated degeneration of the cholinergic system utilizing acetylcholine (ACh) for memory acquisition is observed. Since AD therapy using acetylcholinesterase (AChE) inhibitors are only palliative for memory deficits without reversing disease progress, there is a need for effective therapies, and cell-based therapeutic approaches should fulfil this requirement. We established F3.ChAT human neural stem cells (NSCs) encoding the choline acetyltransferase (ChAT) gene, an ACh-synthesizing enzyme, HMO6.NEP human microglial cells encoding the neprilysin (NEP) gene, an Aβ-degrading enzyme, and HMO6.SRA cells encoding the scavenger receptor A (SRA) gene, an Aβ-uptaking receptor. For the efficacy evaluation of the cells, first, we established an appropriate animal model based on Aβ accumulation and cognitive dysfunction. Among various AD models, intracerebroventricular (ICV) injection of ethylcholine mustard azirinium ion (AF64A) induced the most severe Aβ accumulation and memory dysfunction. Established NSCs and HMO6 cells were transplanted ICV to mice showing memory loss induced by AF64A challenge, and brain Aβ accumulation, ACh concentration and cognitive function were analyzed. All the transplanted F3.ChAT, HMO6.NEP and HMO6.SRA cells were found to survive up to 4 weeks in the mouse brain and expressed their functional genes. Combinational treatment with the NSCs (F3.ChAT) and microglial cells encoding each functional gene (HMO6.NEP or HMO6.SRA) synergistically restored the learning and memory function of AF64A-challenged mice by eliminating Aβ deposits and recovering ACh level. The cells also attenuated inflammatory astrocytic (glial fibrillary acidic protein) response by reducing Aβ accumulation. Taken together, it is expected that NSCs and microglial cells over-expressing ChAT, NEP or SRA genes could be strategies for replacement cell therapy of AD.

Intrauterine desensitization enables long term survival of human oligodendrocyte progenitor cells without immunosuppression

Immune rejection can be reduced using immunosuppressants which are not viable for premature infants. However, desensitization can induce immune tolerance for premature infants because of underdeveloped immune system. The fetuses of Wistar rats at 15-17 days gestation were injected via hOPCs-1 into brain, muscles, and abdomen ex utero and then returned while the fetuses of control without injection. After 6 weeks of desensitization, the brain and muscles were transplanted with hOPCs-1, hNSCs-1, and hOPCs-2. After 10 and 34 weeks of desensitization, hOPCs-1 and hNSCs-1 in desensitized groups was higher than that in the control group while hOPCs-2 were rejected. Treg, CD4CD28, CD8CD28, and CD45RC between the desensitization and the control group differed significantly. Inflammatory cells in group with hOPCs-1 and hNSCs-1 was lower than that in the control group. hOPCs-1 can differentiate into myelin in desensitized groups. Wistar rats with desensitization developed immune tolerance to desensitized and transplanted cells.

Stem cell programming - prospects for perinatal medicine

Recreating human cell and organ systems in vitro has tremendous potential for disease modeling, drug discovery and regenerative medicine. The aim of this short overview is to recapitulate the impressive progress that has been made in the fast-developing field of cell programming during the past years, to illuminate the advantages and limitations of the various cell programming technologies for addressing nervous system disorders and to gauge their impact for perinatal medicine.

Stem cell‐based interventions for the treatment of stroke in newborn infants

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To evaluate the benefits and harms of stem cell‐based interventions for the treatment of stroke in newborn infants compared to control (placebo or no treatment) or stem‐cell based interventions of a different type or source.

Stem cell-based interventions for the prevention and treatment of intraventricular haemorrhage and encephalopathy of prematurity in preterm infants

BACKGROUND

Germinal matrix-intraventricular haemorrhage (GMH-IVH) and encephalopathy of prematurity (EoP) remain substantial issues in neonatal intensive care units worldwide. Current therapies to prevent or treat these conditions are limited. Stem cell-based therapies offer a potential therapeutic approach to repair, restore, or regenerate injured brain tissue. These preclinical findings have now culminated in ongoing human neonatal studies. This is an update of the 2019 review, which did not include EoP.

OBJECTIVES

To evaluate the benefits and harms of stem cell-based interventions for prevention or treatment of GM-IVH and EoP in preterm infants.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search was April 2022.

SELECTION CRITERIA

We attempted to include randomised controlled trials, quasi-randomised controlled trials, and cluster trials comparing 1. stem cell-based interventions versus control; 2. mesenchymal stromal cells (MSCs) of type or source versus MSCs of other type or source; 3. stem cell-based interventions other than MSCs of type or source versus stem cell-based interventions other than MSCs of other type or source; or 4. MSCs versus stem cell-based interventions other than MSCs. For prevention studies, we included extremely preterm infants (less than 28 weeks' gestation), 24 hours of age or less, without ultrasound diagnosis of GM-IVH or EoP; for treatment studies, we included preterm infants (less than 37 weeks' gestation), of any postnatal age, with ultrasound diagnosis of GM-IVH or with EoP.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. all-cause neonatal mortality, 2. major neurodevelopmental disability, 3. GM-IVH, 4. EoP, and 5. extension of pre-existing non-severe GM-IVH or EoP. We planned to use GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We identified no studies that met our inclusion criteria. Three studies are currently registered and ongoing. Phase 1 trials are described in the 'Excluded studies' section.

AUTHORS' CONCLUSIONS

No evidence is currently available to evaluate the benefits and harms of stem cell-based interventions for treatment or prevention of GM-IVH or EoP in preterm infants. We identified three ongoing studies, with a sample size range from 20 to 200. In two studies, autologous cord blood mononuclear cells will be administered to extremely preterm infants via the intravenous route; in one, intracerebroventricular injection of MSCs will be administered to preterm infants up to 34 weeks' gestational age.

The Neuroprotective Effects of Exosomes Derived from TSG101-Overexpressing Human Neural Stem Cells in a Stroke Model

Although tissue-type plasminogen activator was approved by the FDA for early reperfusion of occluded vessels, there is a need for an effective neuroprotective drug for stroke patients. In this study, we established tumor susceptibility gene (TSG)101-overexpressing human neural stem cells (F3.TSG) and investigated whether they showed enhanced secretion of exosomes and whether treatment with exosomes during reperfusion alleviated ischemia-reperfusion-mediated brain damage. F3.TSG cells secreted higher amounts of exosomes than the parental F3 cells. In N2A cells subjected to oxygen–glucose deprivation (OGD), treatment with exosomes or coculture with F3.TSG cells significantly attenuated lactate dehydrogenase release, the mRNA expression of proinflammatory factors, and the protein expression of DNA-damage-related proteins. In a middle cerebral artery occlusion (MCAO) rat model, treatment with exosomes, F3 cells, or F3.TSG cells after 2 h of occlusion followed by reperfusion reduced the infarction volume and suppressed inflammatory cytokines, DNA-damage-related proteins, and glial fibrillary acidic protein, and upregulated several neurotrophic factors. Thus, TSG101-overexpressing neural stem cells showed enhanced exosome secretion; exosome treatment protected against MCAO-induced brain damage via anti-inflammatory activities, DNA damage pathway inhibition, and growth/trophic factor induction. Therefore, exosomes and F3.TSG cells can affect neuroprotection and functional recovery in acute stroke patients.

Diabetes Mellitus-Related Neurobehavioral Deficits in Mice Are Associated With Oligodendrocyte Precursor Cell Dysfunction

Recent clinical studies demonstrated an increase of the incidence of neurobehavioral disorders in patients with diabetes mellitus. Studies also found an association between severity of diabetes mellitus and the progression of white matter hyperintensity on magnetic resonance imaging, which conferred risk for developing cognitive impairment. Since oligodendrocyte precursor cells participated in the white matter repair and remodeling after ischemic brain injury, we explored whether hyperglycemia induced neurobehavioral deficits were associated with dysfunction of oligodendrocyte precursor cells. Adult male C57BL/6 mice (n = 40) were randomly divided into 4-week diabetes, 8-week diabetes, and control groups. Experimental diabetic mice were induced by streptozotocin injection. Learning and cognitive function, exploratory, anxiety and depression behaviors were assessed by Morris water maze, open field test, elevated plus maze, and tail suspension test, respectively. Immunofluorescence staining of neuron-glial antigen 2 and myelin basic protein were performed. Oligodendrocyte precursor cells were cultured in different glucose level to explore possible mechanism in vitro. The learning and cognitive function of 4-week and 8-week diabetic mice were attenuated compared to the control group (p < 0.05). The diabetic mice had less exploratory behavior compared to the control (p < 0.05). However, the diabetic mice were more likely to show anxiety (p < 0.05) and depression (p < 0.01) compared to the control. Further study demonstrated the number of oligodendrocyte precursor cells and the level of myelin basic protein expression were decreased in diabetic mice and the migration and survival ability were suppressed in the hyperglycemic environment in vitro (p < 0.05). Our results demonstrated that diabetes mellitus induced neurological deficits were associated with the decreased number and dysfunction of oligodendrocyte precursor cells.

Role and Mechanism of Ferroptosis in Neurological Diseases

Background

Ferroptosis, as a new form of cell death, is different from other cell deaths such as autophagy or senescence. Ferroptosis involves in the pathophysiological progress of several diseases, including cancers, cardiovascular diseases, nervous system diseases, and kidney damage. Since oxidative stress and iron deposition are the broad pathological features of neurological diseases, the role of ferroptosis in neurological diseases has been widely explored.

Scope of review

Ferroptosis is mainly characterized by changes in iron homeostasis, iron-dependent lipid peroxidation, and glutamate toxicity accumulation, of which can be specifically reversed by ferroptosis inducers or inhibitors. The ferroptosis is mainly regulated by the metabolism of iron, lipids and amino acids through System Xc⁻, voltage-dependent anion channels, p53, p62-Keap1-Nrf2, mevalonate and other pathways. This review also focus on the regulatory pathways of ferroptosis and its research progress in neurological diseases.

Major conclusions

The current researches of ferroptosis in neurological diseases mostly focus on the key pathways of ferroptosis. At the same time, ferroptosis was found playing a bidirectional regulation role in neurological diseases. Therefore, the specific regulatory mechanisms of ferroptosis in neurological diseases still need to be further explored to provide new perspectives for the application of ferroptosis in the treatment of neurological diseases.

PSB0788 ameliorates maternal inflammation-induced periventricular leukomalacia-like injury

Studies have shown that periventricular leukomalacia (PVL) is a distinctive form of cerebral white matter injury that pertains to myelination disturbances. Maternal inflammation is a main cause of white matter injury. Intrauterine inflammation cellular will be propagated to the developing brain by the entire maternal-placental-fetal axis, and triggers neural immune injury. As a low-affinity receptor, adenosine A_2B receptor (A_2BAR) requires high concentrations of adenosine to be significantly activated in pathological conditions. We hypothesized that in the maternal inflammation-induced PVL model, a selective A_2BAR antagonist PSB0788 had the potential to prevent the injury. In this work, a total of 18 SD pregnant rats were divided into three groups, and treated with intraperitoneal injection of phosphate buffered saline (PBS), lipopolysaccharide (LPS), or LPS+PSB0788. Placental infection was determined by H&E staining and the inflammatory condition was determined by ELISA. Change of MBP, NG2 and CC-1 in the brain of the rats' offspring were detected by western blot and immunohistochemistry. Furthermore, LPS-induced maternal inflammation reduced the expression of MBP, which related to the decrease in the numbers of OPCs and mature oligodendrocytes in neonate rats. After treatment with PSB0788, the levels of MBP proteins increased in the rats' offspring, improved the remyelination. In conclusion, our study shows that the selective A_2BAR antagonist PSB0788 plays an important role in promoting the normal development of OPCs in vivo by the maternal inflammation-induced PVL model. Future studies will focus on the mechanism of PSB0788 in this model.

Emerging neuroprotective interventions in periventricular leukomalacia: A systematic review of preclinical studies

INTRODUCTION

Periventricular leukomalacia (PVL) is a result of various antenatal, intrapartum, or postnatal insults to the developing brain and is an important harbinger of cerebral palsy in preterm neonates. There is no proven therapy for PVL. This calls for appraisal of targeted therapies that have been investigated in animal models to evaluate their relevance in clinical research context.

AREAS COVERED

This systematic review identifies interventions that were evaluated in preclinical studies for neuroprotective efficacy against PVL. We identified 142 studies evaluating various interventions in PVL animal models. (Search method is detailed in section 2).

EXPERT OPINION

Interventions that have yielded significant results in preclinical research, and that have been evaluated in a limited number of clinical trials include stem cells, erythropoietin, and melatonin. Many other therapeutic modalities evaluated in preclinical studies have been identified, but more data on their neuroprotective potential in PVL must be garnered before they can be considered for clinical trials. Because most of the tested interventions had only a partial efficacy, a combination of interventions that could be synergistic should be investigated in future preclinical studies. Furthermore, since the nature and pattern of perinatal insults to preterm brain predisposing it to PVL are substantially variable, individualised approaches for the choice of appropriate neuroprotective interventions tailored to different sub-groups of preterm neonates should be explored.

CRHR1 mediates the transcriptional expression of pituitary hormones and their receptors under hypoxia

Hypothalamus-pituitary-adrenal (HPA) axis plays critical roles in stress responses under challenging conditions such as hypoxia, via regulating gene expression and integrating activities of hypothalamus-pituitary-targets cells. However, the transcriptional regulatory mechanisms and signaling pathways of hypoxic stress in the pituitary remain to be defined. Here, we report that hypoxia induced dynamic changes in the transcription factors, hormones, and their receptors in the adult rat pituitary. Hypoxia-inducible factors (HIFs), oxidative phosphorylation, and cAMP signaling pathways were all differentially enriched in genes induced by hypoxic stress. In the pituitary gene network, hypoxia activated c-Fos and HIFs with specific pituitary transcription factors (Prop1), targeting the promoters of hormones and their receptors. HIF and its related signaling pathways can be a promising biomarker during acute or constant hypoxia. Hypoxia stimulated the transcription of marker genes for microglia, chemokines, and cytokine receptors of the inflammatory response. Corticotropin-releasing hormone receptor 1 (CRHR1) mediated the transcription of Pomc, Sstr2, and Hif2a, and regulated the function of HPA axis. Together with HIF, c-Fos initiated and modulated dynamic changes in the transcription of hormones and their receptors. The receptors were also implicated in the regulation of functions of target cells in the pituitary network under hypoxic stress. CRHR1 played an integrative role in the hypothalamus-pituitary-target axes. This study provides new evidence for CRHR1 involved changes of hormones, receptors, signaling molecules and pathways in the pituitary induced by hypoxia.

Transplanted Human Oligodendrocyte Progenitor Cells Restore Neurobehavioral Deficits in a Rat Model of Preterm White Matter Injury

Background: Preterm white matter injury (PWMI) is a common brain injury and a leading cause of life-long neurological deficits in premature infants; however, no effective treatment is available yet. This study aimed to investigate the fate and effectiveness of transplanted human oligodendrocyte progenitor cells (hOPCs) in a rat model of PWMI. Methods: Hypoxia-ischemia was induced in rats at postnatal day 3, and hOPCs (6 × 10⁵ cells/5 μL) were intracerebroventricularly transplanted at postnatal day 7. Neurobehavior was assessed 12 weeks post-transplant using the CatWalk test and Morris water maze test. Histological analyses, as well as immunohistochemical and transmission electron microscopy, were performed after transcardial perfusion. Results: Transplanted hOPCs survived for 13 weeks in PWMI brains. They were widely distributed in the injured white matter, and migrated along the corpus callosum to the contralateral hemisphere. Notably, 82.77 ± 3.27% of transplanted cells differentiated into mature oligodendrocytes, which produced myelin around the axons. Transplantation of hOPCs increased the fluorescence intensity of myelin basic protein and the thickness of myelin sheaths as observed in immunostaining and transmission electron microscopy, while it reduced white matter atrophy at the level of gross morphology. With regard to neurobehavior, the CatWalk test revealed improved locomotor function and inter-paw coordination after transplantation, and the cognitive functions of hOPC-transplanted rats were restored as revealed by the Morris water maze test. Conclusions: Myelin restoration through the transplantation of hOPCs led to neurobehavioral improvements in PWMI rats, suggesting that transplanting hOPCs may provide an effective and promising therapeutic strategy in children with PWMI.

Oligodendrocyte Development and Implication in Perinatal White Matter Injury

Perinatal white matter injury (WMI) is the most common brain injury in premature infants and can lead to life-long neurological deficits such as cerebral palsy. Preterm birth is typically accompanied by inflammation and hypoxic-ischemic events. Such perinatal insults negatively impact maturation of oligodendrocytes (OLs) and cause myelination failure. At present, no treatment options are clinically available to prevent or cure WMI. Given that arrested OL maturation plays a central role in the etiology of perinatal WMI, an increased interest has emerged regarding the functional restoration of these cells as potential therapeutic strategy. Cell transplantation and promoting endogenous oligodendrocyte function are two potential options to address this major unmet need. In this review, we highlight the underlying pathophysiology of WMI with a specific focus on OL biology and their implication for the development of new therapeutic targets.

Neural stem cell treatment for perinatal brain injury: A systematic review and meta-analysis of preclinical studies

Perinatal brain injury can lead to significant neurological and cognitive deficits and currently no therapies can regenerate the damaged brain. Neural stem cells (NSCs) have the potential to engraft and regenerate damaged brain tissue. The aim of this systematic review was to evaluate the preclinical literature to determine whether NSC administration is more effective than controls in decreasing perinatal brain injury. Controlled interventional studies of NSC therapy using animal models of perinatal brain injury were identified using MEDLINE and Embase. Primary outcomes were brain infarct size, motor, and cognitive function. Data for meta‐analysis were synthesized and expressed as standardized mean difference (SMD) with 95% confidence intervals (CI), using a random effects model. We also reported secondary outcomes including NSC survival, migration, differentiation, and effect on neuroinflammation. Eighteen studies met inclusion criteria. NSC administration decreased infarct size (SMD 1.09; CI: 0.44, 1.74, P = .001; I² = 74%) improved motor function measured via the impaired forelimb preference test (SMD 2.27; CI: 0.85, 3.69, P = .002; I² = 86%) and the rotarod test (SMD 1.88; CI: 0.09, 3.67, P = .04; I² = 95%). Additionally, NSCs improved cognitive function measured via the Morris water maze test (SMD of 2.41; CI: 1.16, 3.66, P = .0002; I² = 81%). Preclinical evidence suggests that NSC therapy is promising for the treatment of perinatal brain injury. We have identified key knowledge gaps, including the lack of large animal studies and uncertainty regarding the necessity of immunosuppression for NSC transplantation in neonates. These knowledge gaps should be addressed before NSC treatment can effectively progress to clinical trial.

A novel RIP1/RIP3 dual inhibitor promoted OPC survival and myelination in a rat neonatal white matter injury model with hOPC graft

Background

The dual inhibitors of receptor interacting protein kinase-1 and -3 (RIP1 and RIP3) play an important role in cell death processes and inflammatory responses. White matter injury (WMI), a leading cause of neurodevelopmental disabilities in preterm infants, which is characterized by extensive myelination disturbances and demyelination. Neuroinflammation, leads to the loss and differentiation-inhibition of oligodendrocyte precursor cells (OPCs), represents a major barrier to myelin repair. Whether the novel RIP1/RIP3 dual inhibitor ZJU-37 can promote transplanted OPCs derived from human neural stem cells (hOPCs) survival, differentiation and myelination remains unclear. In this study, we investigated the effect of ZJU-37 on myelination and neurobehavioral function in a neonatal rat WMI model induced by hypoxia and ischemia.

Methods

In vivo, P3 rat pups were subjected to right common carotid artery ligation and hypoxia, and then treated with ZJU-37 or/and hOPCs, then OPCs apoptosis, myelination, glial cell and NLRP3 inflammasome activation together with cognitive outcome were evaluated at 12 weeks after transplantation. In vitro, the effect of ZJU-37 on NLRP3 inflammasome activation in astrocytes induced by oxygen–glucose deprivation (OGD) were examined by western blot and immunofluorescence. The effect of ZJU-37 on OPCs apoptosis induced by the conditioned medium from OGD-injured astrocytes (OGD-astrocyte-CM) was analyzed by flow cytometry and immunofluorescence.

Results

ZJU-37 combined with hOPCs more effectively decreased OPC apoptosis, promoted myelination in the corpus callosum and improved behavioral function compared to ZJU-37 or hOPCs treatment. In addition, the activation of glial cells and NLRP3 inflammasome was reduced by ZJU-37 or/and hOPCs treatment in the neonatal rat WMI model. In vitro, it was also confirmed that ZJU-37 can suppress NLRP3 inflammasome activation in astrocytes induced by OGD. Not only that, the OGD-astrocyte-CM treated with ZJU-37 obviously attenuated OPC apoptosis and dysdifferentiation caused by the OGD-astrocyte-CM.

Conclusions

The novel RIP1/RIP3 dual inhibitor ZJU-37 may promote OPC survival, differentiation and myelination by inhibiting NLRP3 inflammasome activation in a neonatal rat model of WMI with hOPC graft.

Olig2 knockdown alleviates hypoxic-ischemic brain damage in newborn rats

OBJECTIVES

Neuronal damage is an important pathological mechanism in neonatal hypoxic-ischemic brain damage (HIBD). We found in our previous studies that oligodendrocyte transcription factor 2 (Olig2) downregulation was able to increase cell survival in the brain. However, the specific mechanism has yet to be clarified.

METHODS

Sprague-Dawley rats aged 3 d were randomly divided into three groups: the normal control group, the Olig2-RNAi group, and the RNAi-negative control group. The normal control group received no treatment, the Olig2-RNAi group received the Olig2 RNAi adenovirus, and the RNAi-negative control group was given the control adenovirus after the completion of the HIBD model. Infarct lesions and their volumes were observed by triphenyltetrazolium chloride (TTC) staining 3 d after the completion of the adenovirus local injection. The condition of the tissue was characterized by hematoxylin-eosin staining 7 d after the model was established, and cell viability was determined by azure methylene blue staining. Subcellular damage was analyzed by transmission electron microscopy. Rotarod analysis was performed to detect moving behavior ability and an MWM assay was conducted to evaluate the memory.

RESULTS

TTC staining showed a smaller brain injury area in the Olig2-RNAi group than in the RNAi-negative control group. Hematoxylin-eosin staining indicated the presence of severe cell injury in the hippocampal region after HIBD, which improved after Olig2 knockdown. Azure methylene blue staining and electron microscopy results suggested that the cells improved after Olig2 knockdown. The rats stayed longer on the rotating rod, and their latency in the water maze test was gradually shortened relative to that of the rats in the Olig2-RNAi negative control group.

CONCLUSION

Olig2 knockdown can promote the repair of hypoxic-ischemic brain damage in newborn rats.

Developmental toxicity of the novel PFOS alternative OBS in developing zebrafish: An emphasis on cilia disruption

In recent years, sodium p-perfluorous nonenoxybenzene sulfonate (OBS) has emerged as a substitute for PFOS with large demand and application in the Chinese market. However, little is known about potential developmental effects of OBS. In this study, zebrafish embryos were acutely exposed to different concentrations of OBS and the positive control PFOS for a comparative developmental toxicity assessment. OBS caused hatching delays, body axis curvature, neurobehavioral inhibition and abnormal cardiovascular development. These organismal effects were accompanied by change of development related genes expression profile, in which some cases were similar to PFOS. Overall, the toxic effects induced by OBS were generally milder than that of PFOS. Further investigation suggested that both OBS and PFOS disrupted ciliogenesis, evidenced by the ciliary immunostaining, changes in gene expression of kinesin family, dynein arm family and tubulin family members, as well as downregulation of the abundance of motor proteins including KIF3C, DYNC1H1 and DYNC1LI1. The influence of PFOS was stronger than that of OBS on ciliary genes and proteins. Molecular docking analysis revealed that both OBS and PFOS fitted into the motor proteins tightly, but binding affinity between OBS and motor proteins was lower than PFOS. Collectively, OBS and PFOS may act on ciliary motor proteins to interfere with ciliogenesis, leading to ciliary dysfunction and providing a novel probable action mode linked to developmental toxicity. This raises concerns regarding the health risks of the novel PFOS alternative OBS.

Stem cell-based interventions for the prevention of morbidity and mortality following hypoxic-ischaemic encephalopathy in newborn infants

BACKGROUND

Hypoxic-ischaemic encephalopathy (HIE) is a leading cause of mortality and long-term neurological sequelae, affecting thousands of children worldwide. Current therapies to treat HIE are limited to cooling. Stem cell-based therapies offer a potential therapeutic approach to repair or regenerate injured brain tissue. These preclinical findings have now culminated in ongoing human neonatal trials.

OBJECTIVES

To determine the efficacy and safety of stem cell-based interventions for the treatment of hypoxic-ischaemic encephalopathy (HIE) in newborn infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 5), MEDLINE via PubMed (1966 to 8 June 2020), Embase (1980 to 8 June 2020), and CINAHL (1982 to 8 June 2020). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised controlled trials, quasi-randomised controlled trials and cluster trials comparing 1) stem cell-based interventions (any type) compared to control (placebo or no treatment); 2) use of mesenchymal stem/stromal cells (MSCs) of type (e.g. number of doses or passages) or source (e.g. autologous versus allogeneic, or bone marrow versus cord) versus MSCs of other type or source; 3) use of stem cell-based interventions other than MSCs of type (e.g. mononuclear cells, oligodendrocyte progenitor cells, neural stem cells, hematopoietic stem cells, and inducible pluripotent stem cells) or source (e.g. autologous versus allogeneic, or bone marrow versus cord) versus stem cell-based interventions other than MSCs of other type or source; or 4) MSCs versus stem cell-based interventions other than MSCs.

DATA COLLECTION AND ANALYSIS

For each of the included trials, two authors independently planned to extract data (e.g. number of participants, birth weight, gestational age, type and source of MSCs or other stem cell-based interventions) and assess the risk of bias (e.g. adequacy of randomisation, blinding, completeness of follow-up). The primary outcomes considered in this review are all-cause neonatal mortality, major neurodevelopmental disability, death or major neurodevelopmental disability assessed at 18 to 24 months of age. We planned to use the GRADE approach to assess the quality of evidence.

MAIN RESULTS

Our search strategy yielded 616 references. Two review authors independently assessed all references for inclusion. We did not find any completed studies for inclusion. Fifteen RCTs are currently registered and ongoing. We describe the three studies we excluded.

AUTHORS' CONCLUSIONS

There is currently no evidence from randomised trials that assesses the benefit or harms of stem cell-based interventions for the prevention of morbidity and mortality following hypoxic-ischaemic encephalopathy in newborn infants.

Ischemia-Triggered Glutamate Excitotoxicity From the Perspective of Glial Cells

A plethora of neurological disorders shares a final common deadly pathway known as excitotoxicity. Among these disorders, ischemic injury is a prominent cause of death and disability worldwide. Brain ischemia stems from cardiac arrest or stroke, both responsible for insufficient blood supply to the brain parenchyma. Glucose and oxygen deficiency disrupts oxidative phosphorylation, which results in energy depletion and ionic imbalance, followed by cell membrane depolarization, calcium (Ca²⁺) overload, and extracellular accumulation of excitatory amino acid glutamate. If tight physiological regulation fails to clear the surplus of this neurotransmitter, subsequent prolonged activation of glutamate receptors forms a vicious circle between elevated concentrations of intracellular Ca²⁺ ions and aberrant glutamate release, aggravating the effect of this ischemic pathway. The activation of downstream Ca²⁺-dependent enzymes has a catastrophic impact on nervous tissue leading to cell death, accompanied by the formation of free radicals, edema, and inflammation. After decades of “neuron-centric” approaches, recent research has also finally shed some light on the role of glial cells in neurological diseases. It is becoming more and more evident that neurons and glia depend on each other. Neuronal cells, astrocytes, microglia, NG2 glia, and oligodendrocytes all have their roles in what is known as glutamate excitotoxicity. However, who is the main contributor to the ischemic pathway, and who is the unsuspecting victim? In this review article, we summarize the so-far-revealed roles of cells in the central nervous system, with particular attention to glial cells in ischemia-induced glutamate excitotoxicity, its origins, and consequences.

Tuina Massage Improves Cognitive Functions of Hypoxic-Ischemic Neonatal Rats by Regulating Genome-Wide DNA Hydroxymethylation Levels

In addition to abnormalities of motor and posture, children with cerebral palsy (CP) often have intellectual disability. As a complementary and alternative traditional Chinese medicine (TCM) therapy, Chinese Tuina massage, also called Tuina in China, has been widely applied in clinical treatment for CP in China for a long time. However, the molecular basis for this still remains largely unknown. Recently, DNA hydroxymethylation has been shown to be sensitive to environment and plays critical roles in some neurological disorders, whereas the research focusing on the relationship between 5 hmC and Tuina therapy for cerebral palsy is deficient. In our study, we first observed that Tuina improved learning and memory functions of hypoxic-ischemic (HI) rat pups. Meanwhile, 5 hmC level of the temporal lobe cortex in the HI neonatal rat model is decreased significantly compared to that of the rats in control and Tuina groups. Then, we used the hMeDIP-Seq method to explore whether and how DNA hydroxymethylation is involved in Tuina therapy for cerebral palsy. Genomic annotation of DhMRs of HI group's hypo-hydroxymethylation to genes revealed enrichment in multiple neurodevelopmental signaling pathways. Moreover, we found the depletion of 5 hmC modifications in genes associated with neuronal development was accompanied by reduced mRNA levels of these genes. Taken together, our results indicate that Tuina may regulate the expression of neurodevelopment-related genes by changing the status of DNA hydroxymethylation, thereby improving learning and memory functions of cerebral palsy.

Stem cell-based interventions for the prevention and treatment of germinal matrix-intraventricular haemorrhage in preterm infants

BACKGROUND

Germinal matrix-intraventricular haemorrhage (GMH-IVH) remains a substantial issue in neonatal intensive care units worldwide. Current therapies to prevent or treat GMH-IVH are limited. Stem cell-based therapies offer a potential therapeutic approach to repair, restore, and/or regenerate injured brain tissue. These preclinical findings have now culminated in ongoing human neonatal studies.

OBJECTIVES

To determine the benefits and harms of stem cell-based interventions for prevention or treatment of germinal matrix-intraventricular haemorrhage (GM-IVH) in preterm infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 1), in the Cochrane Library; MEDLINE via PubMed (1966 to 7 January 2019); Embase (1980 to 7 January 2019); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 7 January 2019). We also searched clinical trials databases, conference proceedings, and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

We attempted to identify randomised controlled trials, quasi-randomised controlled trials, and cluster trials comparing (1) stem cell-based interventions versus control; (2) mesenchymal stromal cells (MSCs) of type or source versus MSCs of other type or source; (3) stem cell-based interventions other than MSCs of type or source versus stem cell-based interventions other than MSCs of other type or source; or (4) MSCs versus stem cell-based interventions other than MSCs. For prevention studies, we included extremely preterm infants (less than 28 weeks' gestation), 24 hours of age or less, without ultrasound diagnosis of GM-IVH; for treatment studies, we included preterm infants (less than 37 weeks' gestation), of any postnatal age, with ultrasound diagnosis of GM-IVH.

DATA COLLECTION AND ANALYSIS

For each of the included trials, two review authors independently planned to extract data (e.g. number of participants, birth weight, gestational age, type and source of MSCs, other stem cell-based interventions) and assess the risk of bias (e.g. adequacy of randomisation, blinding, completeness of follow-up). Primary outcomes considered in this review are all-cause neonatal mortality, major neurodevelopmental disability, GM-IVH, and extension of pre-existing non-severe GM-IVH. We planned to use the GRADE approach to assess the quality of evidence.

MAIN RESULTS

Our search strategy yielded 769 references. We did not find any completed studies for inclusion. One randomised controlled trial is currently registered and ongoing. Five phase 1 trials are described in the excluded studies.

AUTHORS' CONCLUSIONS

Currently no evidence is available to show the benefits or harms of stem cell-based interventions for treatment or prevention of GM-IVH in preterm infants.

Genome-Wide Alteration of 5-Hydroxymethylcytosine in Hypoxic-Ischemic Neonatal Rat Model of Cerebral Palsy

Cerebral palsy (CP) is a neurodevelopmental disorder usually occurring early in life and persisting through the whole life. Several risk factors, including perinatal hypoxia-ischemia (HI), may contribute to occurrence of CP in preterm infants. DNA hydroxymethylation has been shown to play an important role in neurodevelopment and neurodegenerative disorders. However, the effect of DNA hydroxymethylation in CP remains unknown. The aim of this study is to explore whether and how DNA hydroxymethylation is involved in CP pathogenesis. We observed that overall 5-hydroxymethylcytosine (5hmC) abundance in the cortex of the temporal lobe of rat pups was decreased significantly after hypoxic-ischemic injury, and the reduced expression of Tet1 and Tet2 enzymes might be responsible for this change. Identified differential hydroxymethylation regions (DhMRs) were richly involved in multiple signaling pathways related to neuronal development and function. Furthermore, we found that reduced 5hmC modification on the DhMRs-related genes were accompanied by decrease of their mRNA expression levels. These results suggest that 5hmC modifications are involved in the CP pathogenesis and may potentially serve as a new therapeutic target.