Developmental Neuroscience最新文献

In depth study of pediatric gliomas has been hampered due to difficulties in accessing patient tissue and a lack of clinically representative tumor models. Over the last decade, however, profiling of carefully curated cohorts of pediatric tumors has identified genetic drivers that molecularly segregate pediatric gliomas from adult gliomas. This information has inspired the development of a new set of powerful in vitro and in vivo tumor models that can aid in identifying pediatric-specific oncogenic mechanisms and tumor microenvironment interactions. Single-cell analyses of both human tumors and these newly developed models have revealed that pediatric gliomas arise from spatiotemporally discrete neural progenitor populations in which developmental programs have become dysregulated. Pediatric high-grade gliomas also harbor distinct sets of co-segregating genetic and epigenetic alterations, often accompanied by unique features within the tumor microenvironment. The development of these novel tools and data resources has led to insights into the biology and heterogeneity of these tumors, including identification of distinctive sets of driver mutations, developmentally restricted cells of origin, recognizable patterns of tumor progression, characteristic immune environments, and tumor hijacking of normal microenvironmental and neural programs. As concerted efforts have broadened our understanding of these tumors, new therapeutic vulnerabilities have been identified, and for the first time, promising new strategies are being evaluated in the preclinical and clinical settings. Even so, dedicated and sustained collaborative efforts are necessary to refine our knowledge and bring these new strategies into general clinical use. In this review, we will discuss the range of currently available glioma models, the way in which they have each contributed to recent developments in the field, their benefits and drawbacks for addressing specific research questions, and their future utility in advancing biological understanding and treatment of pediatric glioma.

Background: Ischemic cerebral infarction is one of cerebrovascular diseases with high incidence, disability rate, and mortality globally, and neuronal cell apoptosis is a crucial cause of brain injury during cerebral infarction.

Methods: A middle cerebral artery occlusion (MCAO) model was built in Sprague-Dawley rats to simulate ischemic cerebral infarction. An in vitro model of ischemic cerebral infarction was constructed in BV2 cells with the treatment of oxygen-glucose deprivation (OGD). The role and mechanism of serine/arginine-rich splicing factor 3 (SRSF3) in ischemic cerebral infarction were investigated both in animal and cell models.

Results: The expression of SRSF3 was downregulated in MCAO-treated rats. Overexpression of SRSF3 reduced the neurological scores, brain water content, and infarct volume in MCAO-induced rats. Increased apoptosis in neurons accompanied with the abnormal expressions of apoptosis-related proteins in MCAO-induced rats were revised with the upregulation of SRSF3. Also, a diminished cell viability and elevated apoptosis rate were indicated in OGD-induced BV2 cells, which were reversed with the overexpression of SRSF3. Besides, OGD induced an enhancement in the relative protein expression of programmed cell death protein 4 (PDCD4) and a reduction in the relative expression of p-PI3K/PI3K and p-AKT/AKT, which were inverted with the upregulation of SRSF3 in BV2 cells. Overexpression of PDCD4 abolished the role of SRSF3 in cell viability, apoptosis rate, and the level of the PI3K/AKT pathway in OGD-induced BV2 cells.

Conclusion: SRSF3 improved ischemic cerebral infarction via PDCD4 in vivo and in vitro, which was closely associated with the PI3K/AKT signaling pathway.

Introduction: Fragile X messenger ribonucleoprotein (FMRP) is a protein involved in many neuronal processes in the nervous system including the modulation of synaptic transmission. The loss of FMRP produces the fragile X syndrome (FXS), a neurodevelopmental disorder affecting synaptic and neuronal function and producing cognitive impairments. However, the effects of FXS on short-term processing of synaptic inputs and neuronal outputs in the hippocampus have not yet been sufficiently clarified. Furthermore, it is not known whether dorsal and ventral hippocampi are affected similarly or not in FXS.

Method: We used an Fmr1 knockout (KO) rat model of FXS and recordings of evoked field potentials from the CA1 field of transverse slices from both the dorsal and the ventral hippocampi of adult rats.

Results: Following application of a frequency stimulation protocol consisting of a ten-pulse train and recordings of fEPSP, we found that the dorsal but not ventral KO hippocampus shows altered short-term synaptic plasticity. Furthermore, applying the frequency stimulation protocol and recordings of population spikes, both segments of the KO hippocampus display altered short-term neuronal dynamics.

Conclusions: These data suggest that short-term processing of synaptic inputs is affected in the dorsal, not ventral, FXS hippocampus, while short-term processing of neuronal output is affected in both segments of the FXS hippocampus in a similar way. These FXS-associated changes may have significant impact on the functions of the dorsal and ventral hippocampi in individuals with FXS.

Quantitative analysis of electroencephalography (qEEG) is a potential source of biomarkers for neonatal encephalopathy (NE). However, prior studies using qEEG in NE were limited in their generalizability due to individualized techniques for calculating qEEG features or labor-intensive pre-selection of EEG data. We piloted a fully automated method using commercially available software to calculate the suppression ratio (SR), absolute delta power, and relative delta, theta, alpha, and beta power from EEG of neonates undergoing 72 h of therapeutic hypothermia (TH) for NE between April 20, 2018, and November 4, 2019. We investigated the association of qEEG with degree of encephalopathy (modified Sarnat score), severity of neuroimaging abnormalities following TH (National Institutes of Child Health and Development Neonatal Research Network [NICHD-NRN] score), and presence of seizures. Thirty out of 38 patients met inclusion criteria. A more severe modified Sarnat score was associated with higher SR during all phases of TH, lower absolute delta power during all phases except rewarming, and lower relative delta power during the last 24 h of TH. In 21 patients with neuroimaging data, a worse NICHD-NRN score was associated with higher SR, lower absolute delta power, and higher relative beta power during all phases. QEEG features were not significantly associated with the presence of seizures after correction for multiple comparisons. Our results are consistent with those of prior studies using qEEG in NE and support automated qEEG analysis as an accessible, generalizable method for generating biomarkers of NE and response to TH. Additionally, we found evidence of an immature relative frequency composition in neonates with more severe brain injury, suggesting that automated qEEG analysis may have a use in the assessment of brain maturity.

Glioblastoma (GBM) is the most prevalent and fatal form of brain tumor, which is associated with a poor prognosis. ATP-binding cassette subfamily F member 1 (ABCF1) is an E2 ubiquitin-conjugating enzyme, which is implicated in regulating immune responses and tumorigenesis. Aberrant E3 ubiquitylation has been evidenced in GBM. However, the role of ABCF1 in GBM needs to be further explored. The expression of ABCF1, CXC chemokine ligand 12 (CXCL12), and CXC chemokine receptor 4 (CXCR4) in GBM tissues was examined by the GEPIA tool, real-time PCR and Western blotting. HMC3, U251MG, and LN-229 cells were cultured and transfected with shRNA targeting ABCF1 and ABCF1 plasmids. The proliferative, migrative, and invasive ability of cells was detected. Western blotting was used to detect the levels of phosphorylated phosphatidylinositol 3-kinase (PI3K) and phosphorylated protein kinase B (AKT). We observed that GBM tissues had higher ABCF1, CXCL12, and CXCR4 expression levels. The expression levels of CXCL12 and CXCR4 were enhanced by ABCF1 overexpression, which were significantly reversed by silence of ABCF1 in GBM cells. Silencing ABCF1 or CXCR4 inhibition weakened the capacity of GBM cell growth, migration, and invasion, while ectopic ABCF1 expression or CXCL12 treatment enhanced the cellular function of GBM cells. Furthermore, p-PI3K and p-AKT protein levels were downregulated by ABCF1 knockdown or CXCR4 blockade, which were prompted by ABCF1 overexpression or CXCL12 supplement. The ABCF1-CXCL12-CXCR4 axis was identified as a key player in GBM cell survival and metastasis by activating the PI3K/AKT signaling pathway in GBM cells.

The only current treatment for neonatal hypoxia-ischemia (HI) is therapeutic hypothermia (TH), which still shows some limitations. Specific effects of TH in the several processes involved in brain injury progression remain unclear. In this study, the effects of TH treatment on developmental parameters, behavioral outcomes, and peripheral leukocytes were evaluated in neonatal male and female rats. In P7, animals were submitted to right common carotid artery occlusion followed by hypoxia (8% oxygen). TH was performed by reducing the animal scalp temperature to 32°C for 5 h. Behavioral parameters and developmental landmarks were evaluated. Animals were euthanized at P9 or P21, and cerebral hemispheres, spleen, and thymus were weighed. White blood cells (WBCs) were counted in blood smears. There was a reduction in the weight of the brain hemisphere ipsilateral to the carotid occlusion in HI and TH groups, as well as a reduction in body weight gain and a delay in the opening of the ipsilateral eye. Latency in negative geotaxis was increased by HI at P12. TH did not prevent brain weight loss, developmental impairments, or WBC number changes but prevented negative geotaxis impairment and spleen weight reduction. These data reinforce that a better understanding of the events that occur after HI and TH in both males and females is necessary and would allow the development of more adequate and sex-specific therapeutic approaches.

The genesis of a mature complement of neurons is thought to require, at least in part, precursor cell lineages in which neural progenitors have distinct identities recognized by exclusive expression of one or a few molecular markers. Nevertheless, limited progenitor types distinguished by specific markers and lineal progression through such subclasses cannot easily yield the magnitude of neuronal diversity in most regions of the nervous system. The late Verne Caviness, to whom this edition of Developmental Neuroscience is dedicated, recognized this mismatch. In his pioneering work on the histogenesis of the cerebral cortex, he acknowledged the additional flexibility required to generate multiple classes of cortical projection and interneurons. This flexibility may be accomplished by establishing cell states in which levels rather than binary expression or repression of individual genes vary across each progenitor's shared transcriptome. Such states may reflect local, stochastic signaling via soluble factors or coincidence of cell surface ligand/receptor pairs in subsets of neighboring progenitors. This probabilistic, rather than determined, signaling could modify transcription levels via multiple pathways within an apparently uniform population of progenitors. Progenitor states, therefore, rather than lineal relationships between types may underlie the generation of neuronal diversity in most regions of the nervous system. Moreover, mechanisms that influence variation required for flexible progenitor states may be targets for pathological changes in a broad range of neurodevelopmental disorders, especially those with polygenic origins.

The developing brain is uniquely susceptible to oxidative stress, and endogenous antioxidant mechanisms are not sufficient to prevent injury from a hypoxic-ischemic challenge. Glutathione peroxidase (GPX1) activity reduces hypoxic-ischemic injury. Therapeutic hypothermia (HT) also reduces hypoxic-ischemic injury, in the rodent and the human brain, but the benefit is limited. Here, we combined GPX1 overexpression with HT in a P9 mouse model of hypoxia-ischemia (HI) to test the effectiveness of both treatments together. Histological analysis showed that wild-type (WT) mice with HT were less injured than WT with normothermia. In the GPX1-tg mice, however, despite a lower median score in the HT-treated mice, there was no significant difference between HT and normothermia. GPX1 protein expression was higher in the cortex of all transgenic groups at 30 min and 24 h, as well as in WT 30 min after HI, with and without HT. GPX1 was higher in the hippocampus of all transgenic groups and WT with HI and normothermia, at 24 h, but not at 30 min. Spectrin 150 was higher in all groups with HI, while spectrin 120 was higher in HI groups only at 24 h. There was reduced ERK1/2 activation in both WT and GPX1-tg HI at 30 min. Thus, with a relatively moderate insult, we see a benefit with cooling in the WT but not the GPX1-tg mouse brain. The fact that we see no benefit with increased GPx1 here in the P9 model (unlike in the P7 model) may indicate that oxidative stress in these older mice is elevated to an extent that increased GPx1 is insufficient for reducing injury. The lack of benefit of overexpressing GPX1 in conjunction with HT after HI indicates that pathways triggered by GPX1 overexpression may interfere with the neuroprotective mechanisms provided by HT.

The developmental condition of children after neonatal arterial ischemic stroke (NAIS) is characterized by cognitive and motor impairments. We hypothesized that independent walking age would be a predictor of later global cognitive functioning in this population. Sixty-one children with an available independent walking age and full-scale intelligence quotient (IQ) score 7 years after NAIS were included in this study. Full-scale IQ was assessed using the fourth edition of the Wechsler Intelligence Scale for Children (WISC-IV). Independent walking age was negatively correlated with full-scale IQ score at 7 years of age (Pearson correlation coefficient of -0.27; 95% confidence interval from -0.48 to -0.01; p < 0.05). Early motor function is correlated with later global cognitive functioning in children after NAIS. Assessing and promoting early motor ability is essential in this population.