-
Journal of Neuroinflammation Jan 2024Preterm birth is often associated with chorioamnionitis and leads to increased risk of neurodevelopmental disorders, such as autism. Preterm birth can lead to cerebellar...
BACKGROUND
Preterm birth is often associated with chorioamnionitis and leads to increased risk of neurodevelopmental disorders, such as autism. Preterm birth can lead to cerebellar underdevelopment, but the mechanisms of disrupted cerebellar development in preterm infants are not well understood. The cerebellum is consistently affected in people with autism spectrum disorders, showing reduction of Purkinje cells, decreased cerebellar grey matter, and altered connectivity.
METHODS
Preterm rhesus macaque fetuses were exposed to intra-amniotic LPS (1 mg, E. coli O55:B5) at 127 days (80%) gestation and delivered by c-section 5 days after injections. Maternal and fetal plasma were sampled for cytokine measurements. Chorio-decidua was analyzed for immune cell populations by flow cytometry. Fetal cerebellum was sampled for histology and molecular analysis by single-nuclei RNA-sequencing (snRNA-seq) on a 10× chromium platform. snRNA-seq data were analyzed for differences in cell populations, cell-type specific gene expression, and inferred cellular communications.
RESULTS
We leveraged snRNA-seq of the cerebellum in a clinically relevant rhesus macaque model of chorioamnionitis and preterm birth, to show that chorioamnionitis leads to Purkinje cell loss and disrupted maturation of granule cells and oligodendrocytes in the fetal cerebellum at late gestation. Purkinje cell loss is accompanied by decreased sonic hedgehog signaling from Purkinje cells to granule cells, which show an accelerated maturation, and to oligodendrocytes, which show accelerated maturation from pre-oligodendrocytes into myelinating oligodendrocytes.
CONCLUSION
These findings suggest a role of chorioamnionitis on disrupted cerebellar maturation associated with preterm birth and on the pathogenesis of neurodevelopmental disorders among preterm infants.
Topics: Infant, Newborn; Female; Infant; Animals; Humans; Pregnancy; Hedgehog Proteins; Macaca mulatta; Chorioamnionitis; Premature Birth; Escherichia coli; Infant, Premature; Cerebellum; RNA, Small Nuclear
PubMed: 38200558
DOI: 10.1186/s12974-024-03012-y -
Science Advances Jan 2024Transcription factors play vital roles in neuron development; however, little is known about the role of these proteins in maintaining neuronal homeostasis. Here, we...
Transcription factors play vital roles in neuron development; however, little is known about the role of these proteins in maintaining neuronal homeostasis. Here, we show that the transcription factor RREB1 (Ras-responsive element-binding protein 1) is essential for neuron survival in the mammalian brain. A spontaneous mouse mutation causing loss of a nervous system-enriched transcript is associated with progressive loss of cerebellar Purkinje cells and ataxia. Analysis of chromatin immunoprecipitation and sequencing, along with RNA sequencing data revealed dysregulation of RREB1 targets associated with the microtubule cytoskeleton. In agreement with the known role of microtubules in dendritic development, dendritic complexity was disrupted in -deficient neurons. Analysis of sequencing data also suggested that RREB1 plays a role in the endomembrane system. Mutant Purkinje cells had fewer numbers of autophagosomes and lysosomes and contained P62- and ubiquitin-positive inclusions. Together, these studies demonstrate that RREB1 functions to maintain the microtubule network and proteostasis in mammalian neurons.
Topics: Animals; Mice; Mammals; Microtubules; Neurons; Proteostasis; Purkinje Cells; Transcription Factors
PubMed: 38198538
DOI: 10.1126/sciadv.adh3929 -
PloS One 2024We identified two different inherited mutations in KCNH2 gene, or human ether-a-go-go related gene (hERG), which are linked to Long QT Syndrome. The first mutation was...
We identified two different inherited mutations in KCNH2 gene, or human ether-a-go-go related gene (hERG), which are linked to Long QT Syndrome. The first mutation was in a 1-day-old infant, whereas the second was in a 14-year-old girl. The two KCNH2 mutations were transiently transfected into either human embryonic kidney (HEK) cells or human induced pluripotent stem-cell derived cardiomyocytes. We performed associated multiscale computer simulations to elucidate the arrhythmogenic potentials of the KCNH2 mutations. Genetic screening of the first and second index patients revealed a heterozygous missense mutation in KCNH2, resulting in an amino acid change (P632L) in the outer loop of the channel and substitution at position 428 from serine to proline (S428P), respectively. Heterologous expression of P632L and S428P into HEK cells produced no hERG current compared to the wild type (WT). Moreover, the co-transfection of WT and P632L yielded no hERG current; however, the co-transfection of WT and S428P yielded partial hERG current. Action potentials were prolonged in a complete or partial blockade of hERG current from computer simulations which was more severe in Purkinje than ventricular myocytes. Three dimensional simulations revealed a higher susceptibility to reentry in the presence of hERG current blockade. Our experimental findings suggest that both P632L and S428P mutations may impair the KCNH2 gene. The Purkinje cells exhibit a more severe phenotype than ventricular myocytes, and the hERG current blockade renders the ventricles an arrhythmogenic substrate from computer modeling.
Topics: Adolescent; Female; Humans; Infant; Action Potentials; Computer Simulation; Epithelial Cells; ERG1 Potassium Channel; Long QT Syndrome; Mutation
PubMed: 38181028
DOI: 10.1371/journal.pone.0287206 -
Brain Structure & Function Mar 2024The primate hippocampus includes the dentate gyrus, cornu ammonis (CA), and subiculum. CA is subdivided into four fields (CA1-CA3, plus CA3h/hilus of the dentate gyrus)...
The primate hippocampus includes the dentate gyrus, cornu ammonis (CA), and subiculum. CA is subdivided into four fields (CA1-CA3, plus CA3h/hilus of the dentate gyrus) with specific pyramidal cell morphology and connections. Work in non-human mammals has shown that hippocampal connectivity is precisely patterned both in the laminar and longitudinal axes. One of the main handicaps in the study of neuropathological semiology in the human hippocampus is the lack of clear laminar and longitudinal borders. The aim of this study was to explore a histochemical segmentation of the adult human hippocampus, integrating field (medio-lateral), laminar, and anteroposterior longitudinal patterning. We provide criteria for head-body-tail field and subfield parcellation of the human hippocampus based on immunodetection of Rabphilin3a (Rph3a), Purkinje-cell protein 4 (PCP4), Chromogranin A and Regulation of G protein signaling-14 (RGS-14). Notably, Rph3a and PCP4 allow to identify the border between CA3 and CA2, while Chromogranin A and RGS-14 give specific staining of CA2. We also provide novel histological data about the composition of human-specific regions of the anterior and posterior hippocampus. The data are given with stereotaxic coordinates along the longitudinal axis. This study provides novel insights for a detailed region-specific parcellation of the human hippocampus useful for human brain imaging and neuropathology.
Topics: Adult; Animals; Humans; Chromogranin A; Hippocampus; Brain; Head; Imaging, Three-Dimensional; Magnetic Resonance Imaging; Mammals
PubMed: 38180568
DOI: 10.1007/s00429-023-02725-9 -
Science Advances Jan 2024The ability to predict the future based on past experience lies at the core of the brain's ability to adapt behavior. However, the neural mechanisms that participate in...
The ability to predict the future based on past experience lies at the core of the brain's ability to adapt behavior. However, the neural mechanisms that participate in generating and updating predictions are not clearly understood. Further, the evolutionary antecedents and the prevalence of predictive processing among vertebrates are even less explored. Here, we show evidence of predictive processing via the involvement of cerebellar circuits in larval zebrafish. We presented stereotyped optic flow stimuli to larval zebrafish to evoke swims and discovered that lesioning the cerebellum abolished prediction-dependent modulation of swim latency. When expectations of optic flow direction did not match with reality, error signals arrive at Purkinje cells via the olivary climbing fibers, whereas granule cells and Purkinje cells encode signals of expectation. Strong neural representations of expectation correlate with faster swim responses and vice versa. In sum, our results show evidence for predictive processing in nonmammalian vertebrates with the involvement of cerebellum, an evolutionarily conserved brain structure.
Topics: Animals; Zebrafish; Larva; Cerebellum; Purkinje Cells; Neurons
PubMed: 38170763
DOI: 10.1126/sciadv.adi6470 -
Theranostics 2024The neurobiological basis of gaining consciousness from unconscious state induced by anesthetics remains unknown. This study was designed to investigate the involvement...
The neurobiological basis of gaining consciousness from unconscious state induced by anesthetics remains unknown. This study was designed to investigate the involvement of the cerebello-thalamus-motor cortical loop mediating consciousness transitions from the loss of consciousness (LOC) induced by an inhalational anesthetic sevoflurane in mice. The neural tracing and fMRI together with optochemogenetic manipulation were used to investigate the potential link among cerebello-thalamus-motor cortical brain regions. The fiber photometry of calcium and neurotransmitters, including glutamate (Glu), γ-aminobutyric acid (GABA) and norepinephrine (NE), were monitored from the motor cortex (M1) and the 5 lobule of the cerebellar vermis (5Cb) during unconsciousness induced by sevoflurane and gaining consciousness after sevoflurane exposure. Cerebellar Purkinje cells were optogenetically manipulated to investigate their influence on consciousness transitions during and after sevoflurane exposure. Activation of 5Cb Purkinje cells increased the Ca flux in the M1 CaMKIIα neurons, but this increment was significantly reduced by inactivation of posterior and parafascicular thalamic nucleus The 5Cb and M1 exhibited concerted calcium flux, and glutamate and GABA release during transitions from wakefulness, loss of consciousness, burst suppression to conscious recovery. Ca flux and Glu release in the M1, but not in the 5Cb, showed a strong synchronization with the EEG burst suppression, particularly, in the gamma-band range. In contrast, the Glu, GABA and NE release and Ca oscillations were coherent with the EEG gamma band activity only in the 5Cb during the pre-recovery of consciousness period. The optogenetic activation of Purkinje cells during burst suppression significantly facilitated emergence from anesthesia while the optogenetic inhibition prolonged the time to gaining consciousness. Our data indicate that cerebellar neuronal communication integrated with motor cortex through thalamus promotes consciousness recovery from anesthesia which may likely serve as arousal regulation.
Topics: Mice; Animals; Consciousness; Sevoflurane; Purkinje Cells; Calcium; Motor Cortex; Unconsciousness; Neurons; Anesthesia; Glutamates; gamma-Aminobutyric Acid
PubMed: 38169536
DOI: 10.7150/thno.89592 -
Communications Biology Jan 2024Purkinje cells in the cerebellum are among the largest neurons in the brain and have been extensively investigated in rodents. However, their morphological and...
Purkinje cells in the cerebellum are among the largest neurons in the brain and have been extensively investigated in rodents. However, their morphological and physiological properties remain poorly understood in humans. In this study, we utilized high-resolution morphological reconstructions and unique electrophysiological recordings of human Purkinje cells ex vivo to generate computational models and estimate computational capacity. An inter-species comparison showed that human Purkinje cell had similar fractal structures but were larger than those of mouse Purkinje cells. Consequently, given a similar spine density (2/μm), human Purkinje cell hosted approximately 7.5 times more dendritic spines than those of mice. Moreover, human Purkinje cells had a higher dendritic complexity than mouse Purkinje cells and usually emitted 2-3 main dendritic trunks instead of one. Intrinsic electro-responsiveness was similar between the two species, but model simulations revealed that the dendrites could process ~6.5 times (n = 51 vs. n = 8) more input patterns in human Purkinje cells than in mouse Purkinje cells. Thus, while human Purkinje cells maintained spike discharge properties similar to those of rodents during evolution, they developed more complex dendrites, enhancing computational capacity.
Topics: Animals; Mice; Humans; Purkinje Cells; Cerebellum; Neurons; Dendrites
PubMed: 38168772
DOI: 10.1038/s42003-023-05689-y -
BioRxiv : the Preprint Server For... Dec 2023Genetic variants in multiple sphingolipid biosynthesis genes cause human brain disorders. A recent study collected patients from twelve unrelated families with variants...
Genetic variants in multiple sphingolipid biosynthesis genes cause human brain disorders. A recent study collected patients from twelve unrelated families with variants in the gene , a neutral sphingomyelinase which metabolizes sphingomyelin into ceramide at an early stage of the biosynthesis pathway. These patients have severe developmental brain malformations including microcephaly and cerebellar hypoplasia. However, the mechanism of was not known and we pursued a new mouse model. We hypothesized that the role of in producing ceramide is important for making primary cilia, a crucial organelle mediating cellular signaling. We found that the mouse model has cerebellar hypoplasia due to failure of Purkinje cell development. Human induced pluripotent stem cells exhibit neural progenitor cell death and have shortened primary cilia which is rescued by adding exogenous ceramide. production of ceramide is crucial for human brain development.
PubMed: 38168190
DOI: 10.1101/2023.12.15.571873 -
Cell Reports Jan 2024While ATM loss of function has long been identified as the genetic cause of ataxia-telangiectasia (A-T), how it leads to selective and progressive degeneration of...
While ATM loss of function has long been identified as the genetic cause of ataxia-telangiectasia (A-T), how it leads to selective and progressive degeneration of cerebellar Purkinje and granule neurons remains unclear. ATM expression is enriched in microglia throughout cerebellar development and adulthood. Here, we find evidence of microglial inflammation in the cerebellum of patients with A-T using single-nucleus RNA sequencing. Pseudotime analysis revealed that activation of A-T microglia preceded upregulation of apoptosis-related genes in granule and Purkinje neurons and that microglia exhibited increased neurotoxic cytokine signaling to granule and Purkinje neurons in A-T. To confirm these findings experimentally, we performed transcriptomic profiling of A-T induced pluripotent stem cell (iPSC)-derived microglia, which revealed cell-intrinsic microglial activation of cytokine production and innate immune response pathways compared to controls. Furthermore, A-T microglia co-culture with either control or A-T iPSC-derived neurons was sufficient to induce cytotoxicity. Taken together, these studies reveal that cell-intrinsic microglial activation may promote neurodegeneration in A-T.
Topics: Humans; Ataxia Telangiectasia; Microglia; Ataxia Telangiectasia Mutated Proteins; Neurons; Cytokines
PubMed: 38159274
DOI: 10.1016/j.celrep.2023.113622 -
Biophysical Journal Dec 2023Discovered just over 25 years ago in cerebellar Purkinje neurons, resurgent Na current was originally described operationally as a component of voltage-gated Na current... (Review)
Review
Discovered just over 25 years ago in cerebellar Purkinje neurons, resurgent Na current was originally described operationally as a component of voltage-gated Na current that flows upon repolarization from relatively depolarized potentials and speeds recovery from inactivation, increasing excitability. Its presence in many excitable cells and absence from others has raised questions regarding its biophysical and molecular mechanisms. Early studies proposed that Na channels capable of generating resurgent current are subject to a rapid open-channel block by an endogenous blocking protein, which binds upon depolarization and unblocks upon repolarization. Since the time that this mechanism was suggested, many physiological and structural studies of both Na and K channels have revealed aspects of gating and conformational states that provide insights into resurgent current. These include descriptions of domain movements for activation and inactivation, solution of cryo-EM structures with pore-blocking compounds, and identification of native blocking domains, proteins, and modulatory subunits. Such results not only allow the open-channel block hypothesis to be refined but also link it more clearly to research that preceded it. This review considers possible mechanisms for resurgent Na current in the context of earlier and later studies of ion channels and suggests a framework for future research.
PubMed: 38130058
DOI: 10.1016/j.bpj.2023.12.016