scholarly journals Astrocytes in Down Syndrome Across the Lifespan

2021 ◽  
Vol 15 ◽  
Author(s):  
Blandine Ponroy Bally ◽  
Keith K. Murai
Keyword(s):  
Down Syndrome ◽  
Brain Development ◽  
Chromosome 21 ◽  
Early Brain Development ◽  
The Central Nervous System ◽  
Circuit Development ◽  
And Function ◽  
The Impact ◽  
The Brain

Down Syndrome (DS) is the most common genetic cause of intellectual disability in which delays and impairments in brain development and function lead to neurological and cognitive phenotypes. Traditionally, a neurocentric approach, focusing on neurons and their connectivity, has been applied to understanding the mechanisms involved in DS brain pathophysiology with an emphasis on how triplication of chromosome 21 leads to alterations in neuronal survival and homeostasis, synaptogenesis, brain circuit development, and neurodegeneration. However, recent studies have drawn attention to the role of non-neuronal cells, especially astrocytes, in DS. Astrocytes comprise a large proportion of cells in the central nervous system (CNS) and are critical for brain development, homeostasis, and function. As triplication of chromosome 21 occurs in all cells in DS (with the exception of mosaic DS), a deeper understanding of the impact of trisomy 21 on astrocytes in DS pathophysiology is warranted and will likely be necessary for determining how specific brain alterations and neurological phenotypes emerge and progress in DS. Here, we review the current understanding of the role of astrocytes in DS, and discuss how specific perturbations in this cell type can impact the brain across the lifespan from early brain development to adult stages. Finally, we highlight how targeting, modifying, and/or correcting specific molecular pathways and properties of astrocytes in DS may provide an effective therapeutic direction given the important role of astrocytes in regulating brain development and function.

scholarly journals Human iPSC-derived Down syndrome astrocytes display genome-wide perturbations in gene expression, an altered adhesion profile, and increased cellular dynamics

2020 ◽  
Vol 29 (5) ◽  
pp. 785-802 ◽  
Author(s):  
Blandine Ponroy Bally ◽  
W Todd Farmer ◽  
Emma V Jones ◽  
Selin Jessa ◽  
J Benjamin Kacerovsky ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Down Syndrome ◽  
Cell Adhesion ◽  
Brain Development ◽  
Trisomy 21 ◽  
Chromatin Accessibility ◽  
Chromosome 21 ◽  
Genome Wide ◽  
And Function ◽  
The Impact

Abstract Down syndrome (DS), caused by the triplication of human chromosome 21, leads to significant alterations in brain development and is a major genetic cause of intellectual disability. While much is known about changes to neurons in DS, the effects of trisomy 21 on non-neuronal cells such as astrocytes are poorly understood. Astrocytes are critical for brain development and function, and their alteration may contribute to DS pathophysiology. To better understand the impact of trisomy 21 on astrocytes, we performed RNA-sequencing on astrocytes from newly produced DS human induced pluripotent stem cells (hiPSCs). While chromosome 21 genes were upregulated in DS astrocytes, we found consistent up- and down-regulation of genes across the genome with a strong dysregulation of neurodevelopmental, cell adhesion and extracellular matrix molecules. ATAC (assay for transposase-accessible chromatin)-seq also revealed a global alteration in chromatin state in DS astrocytes, showing modified chromatin accessibility at promoters of cell adhesion and extracellular matrix genes. Along with these transcriptomic and epigenomic changes, DS astrocytes displayed perturbations in cell size and cell spreading as well as modifications to cell-cell and cell-substrate recognition/adhesion, and increases in cellular motility and dynamics. Thus, triplication of chromosome 21 is associated with genome-wide transcriptional, epigenomic and functional alterations in astrocytes that may contribute to altered brain development and function in DS.

The Impact of Phytosterols on the Healthy and Diseased Brain

2019 ◽  
Vol 26 (37) ◽  
pp. 6750-6765 ◽  
Author(s):  
Tess Dierckx ◽  
Jeroen F.J. Bogie ◽  
Jerome J.A. Hendriks
Keyword(s):  
Cholesterol Metabolism ◽  
Neurological Diseases ◽  
Physiological Role ◽  
Cholesterol Homeostasis ◽  
Brain Functioning ◽  
The Central Nervous System ◽  
And Function ◽  
The Impact ◽  
The Brain

The central nervous system (CNS) is the most cholesterol-rich organ in mammals. Cholesterol homeostasis is essential for proper brain functioning and dysregulation of cholesterol metabolism can lead to neurological problems. Multiple sclerosis (MS) and Alzheimer’s disease (AD) are examples of neurological diseases that are characterized by a disturbed cholesterol metabolism. Phytosterols (PS) are plant-derived components that structurally and functionally resemble cholesterol. PS are known for their cholesterol-lowering properties. Due to their ability to reach the brain, researchers have started to investigate the physiological role of PS in the CNS. In this review, the metabolism and function of PS in the diseased and healthy CNS are discussed.

scholarly journals The Role of Adrenoceptors in the Retina

Cells ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2594
Author(s):  
Yue Ruan ◽  
Tobias Böhmer ◽  
Subao Jiang ◽  
Adrian Gericke
Keyword(s):  
Visual Information ◽  
Vision Loss ◽  
Retinal Diseases ◽  
System A ◽  
The Central Nervous System ◽  
The Individual ◽  
And Function ◽  
The Brain

The retina is a part of the central nervous system, a thin multilayer with neuronal lamination, responsible for detecting, preprocessing, and sending visual information to the brain. Many retinal diseases are characterized by hemodynamic perturbations and neurodegeneration leading to vision loss and reduced quality of life. Since catecholamines and respective bindings sites have been characterized in the retina, we systematically reviewed the literature with regard to retinal expression, distribution and function of alpha1 (α1)-, alpha2 (α2)-, and beta (β)-adrenoceptors (ARs). Moreover, we discuss the role of the individual adrenoceptors as targets for the treatment of retinal diseases.

scholarly journals A sart1 Zebrafish Mutant Results in Developmental Defects in the Central Nervous System

Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2340
Author(s):  
Hannah E. Henson ◽  
Michael R. Taylor
Keyword(s):  
Central Nervous System ◽  
Cell Death ◽  
Nervous System ◽  
Developmental Defects ◽  
Whole Exome ◽  
The Central Nervous System ◽  
And Function ◽  
Upregulated Genes ◽  
The Brain

The spliceosome consists of accessory proteins and small nuclear ribonucleoproteins (snRNPs) that remove introns from RNA. As splicing defects are associated with degenerative conditions, a better understanding of spliceosome formation and function is essential. We provide insight into the role of a spliceosome protein U4/U6.U5 tri-snRNP-associated protein 1, or Squamous cell carcinoma antigen recognized by T-cells (Sart1). Sart1 recruits the U4.U6/U5 tri-snRNP complex to nuclear RNA. The complex then associates with U1 and U2 snRNPs to form the spliceosome. A forward genetic screen identifying defects in choroid plexus development and whole-exome sequencing (WES) identified a point mutation in exon 12 of sart1 in Danio rerio (zebrafish). This mutation caused an up-regulation of sart1. Using RNA-Seq analysis, we identified additional upregulated genes, including those involved in apoptosis. We also observed increased activated caspase 3 in the brain and eye and down-regulation of vision-related genes. Although splicing occurs in numerous cells types, sart1 expression in zebrafish was restricted to the brain. By identifying sart1 expression in the brain and cell death within the central nervous system (CNS), we provide additional insights into the role of sart1 in specific tissues. We also characterized sart1’s involvement in cell death and vision-related pathways.

scholarly journals Potential Role of JAK-STAT Signaling Pathway in the Neurogenic-to-Gliogenic Shift in Down Syndrome Brain

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Han-Chung Lee ◽  
Kai-Leng Tan ◽  
Pike-See Cheah ◽  
King-Hwa Ling
Keyword(s):  
Down Syndrome ◽  
Brain Development ◽  
Cell Fate ◽  
Mouse Models ◽  
Neuronal Cell ◽  
Janus Kinase ◽  
Chromosome 21 ◽  
Severe Intellectual Disability ◽  
Stat Signaling

Trisomy of human chromosome 21 in Down syndrome (DS) leads to several phenotypes, such as mild-to-severe intellectual disability, hypotonia, and craniofacial dysmorphisms. These are fundamental hallmarks of the disorder that affect the quality of life of most individuals with DS. Proper brain development involves meticulous regulation of various signaling pathways, and dysregulation may result in abnormal neurodevelopment. DS brain is characterized by an increased number of astrocytes with reduced number of neurons. In mouse models for DS, the pool of neural progenitor cells commits to glia rather than neuronal cell fate in the DS brain. However, the mechanism(s) and consequences of this slight neurogenic-to-gliogenic shift in DS brain are still poorly understood. To date, Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling has been proposed to be crucial in various developmental pathways, especially in promoting astrogliogenesis. Since both human and mouse models of DS brain exhibit less neurons and a higher percentage of cells with astrocytic phenotypes, understanding the role of JAK-STAT signaling in DS brain development will provide novel insight into its role in the pathogenesis of DS brain and may serve as a potential target for the development of effective therapy to improve DS cognition.

scholarly journals Type I Interferon Signaling Drives Microglial Dysfunction and Senescence in Human iPSC Models of Down Syndrome and Alzheimers Disease

2021 ◽  
Author(s):  
Mengmeng Jin ◽  
Ranji Xu ◽  
Mahabub Maraj Alam ◽  
Ziyuan Ma ◽  
Sining Zhu ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Brain Development ◽  
Type I Interferon ◽  
Chromosome 21 ◽  
Type I ◽  
Chimeric Mouse ◽  
Interferon Signaling ◽  
Alzheimers Disease ◽  
Human Microglia ◽  
The Impact

Microglia are critical for brain development and play a central role in Alzheimers disease (AD) etiology. Down syndrome (DS), also known as trisomy 21, is the most common genetic origin of intellectual disability and the most common risk factor for AD. Surprisingly, little information is available on the impact of trisomy of human chromosome 21 (Hsa21) on microglia in DS brain development and AD in DS (DSAD). Using our new induced pluripotent stem cell (iPSC)-based human microglia-containing cerebral organoid and chimeric mouse brain models, here we report that DS microglia exhibit enhanced synaptic pruning function during brain development. Consequently, electrophysiological recordings demonstrate that DS microglial mouse chimeras show impaired synaptic neurotransmission, as compared to control microglial chimeras. Upon being exposed to human brain tissue-derived soluble pathological tau, DS microglia display dystrophic phenotypes in chimeric mouse brains, recapitulating microglial responses seen in human AD and DSAD brain tissues. Further flow cytometry, single-cell RNA-sequencing, and immunohistological analyses of chimeric mouse brains demonstrate that DS microglia undergo cellular senescence and exhibit elevated type I interferon signaling after being challenged by pathological tau. Mechanistically, we find that shRNA-mediated knockdown of Hsa21encoded type I interferon receptor genes, IFNARs, rescues the defective DS microglial phenotypes both during brain development and in response to pathological tau. Our findings provide first in vivo evidence supporting a paradigm shifting theory that human microglia respond to pathological tau by exhibiting accelerated senescence and dystrophic phenotypes. Our results further suggest that targeting IFNARs may improve microglial functions during DS brain development and prevent human microglial senescence in DS individuals with AD.

scholarly journals Non-linear effects of socioeconomic status on brain development: associations between parental occupation, cortical thickness and language skills in childhood and adolescence

2019 ◽  
Author(s):  
Budhachandra Khundrakpam ◽  
Suparna Choudhury ◽  
Uku Vainik ◽  
Noor Al-Sharif ◽  
Neha Bhutani ◽  
...  
Keyword(s):  
Socioeconomic Status ◽  
Cognitive Development ◽  
Brain Development ◽  
Cortical Thickness ◽  
Early Adolescence ◽  
Life Outcomes ◽  
Parental Occupation ◽  
The Impact ◽  
The Brain

AbstractStudies have pointed to the role of the brain in mediating the effects of the social environment of the developing child on life outcomes. Since brain development involves nonlinear trajectories, these effects of the child’s social context will likely have age-related differential associations with the brain. However, there is still a dearth of integrative research investigating the interplay between neurodevelopmental trajectories, social milieu and life outcomes. We set out to fill this gap, focusing specifically on the role of socioeconomic status, SES (indexed by parental occupation) on brain and cognitive development by analyzing MRI scans from 757 typically-developing subjects (age = 3-21 years). We observed nonlinear interaction of age and SES on cortical thickness, specifically a significant positive association between SES and thickness around 9-13 years at several cortical regions. Using a moderated mediation model, we observed that cortical thickness mediated the link between SES and language abilities, and this mediation was moderated by ‘age’ in a quadratic pattern, indicating a pronounced SES-effect during early adolescence. Our results, drawn from cross-sectional data, provide a basis for further longitudinal studies to test whether early adolescence may be a sensitive time window for the impact of SES on brain and cognitive development.

scholarly journals Behavioural significance of prolactin signalling in the central nervous system during pregnancy and lactation

Reproduction ◽  
2002 ◽  
pp. 497-506 ◽  
Author(s):  
DR Grattan
Keyword(s):  
Hormone Secretion ◽  
Maternal Brain ◽  
Pregnancy And Lactation ◽  
The Central Nervous System ◽  
Hypothalamic Function ◽  
And Function ◽  
Gland Development ◽  
The Brain ◽  
Behavioural Significance

The role of prolactin in the regulation of mammary gland development and function during pregnancy and lactation is well established. However, in addition, prolactin appears to have a much wider role in the physiology of lactation. There is widespread expression of prolactin receptors in the hypothalamus during lactation, indicative of a multi-faceted role for prolactin in regulating hypothalamic function. During pregnancy and lactation, the maternal brain undergoes structural and functional modification, allowing the establishment of appropriate behaviour to feed and nurture the offspring, to adjust to the nutritional and metabolic demands of milk production, and to maintain appropriate hormone secretion to allow milk synthesis, secretion and ejection. The coordination of such a range of neurobiological and neuroendocrine adaptations requires an endocrine signalling mechanism, capable of communicating the reproductive state to the brain. Evidence indicates that prolactin is part of this mechanism.

scholarly journals The Microbiota–Gut–Brain Axis and Alzheimer Disease. From Dysbiosis to Neurodegeneration: Focus on the Central Nervous System Glial Cells

2021 ◽  
Vol 10 (11) ◽  
pp. 2358
Author(s):  
Maria Grazia Giovannini ◽  
Daniele Lana ◽  
Chiara Traini ◽  
Maria Giuliana Vannucchi
Keyword(s):  
Alzheimer Disease ◽  
Glial Cells ◽  
Cell Types ◽  
The Past ◽  
The Central Nervous System ◽  
Diseased State ◽  
The Brain ◽  
Alzheimer Disease Pathogenesis ◽  
Brain Homeostasis

The microbiota–gut system can be thought of as a single unit that interacts with the brain via the “two-way” microbiota–gut–brain axis. Through this axis, a constant interplay mediated by the several products originating from the microbiota guarantees the physiological development and shaping of the gut and the brain. In the present review will be described the modalities through which the microbiota and gut control each other, and the main microbiota products conditioning both local and brain homeostasis. Much evidence has accumulated over the past decade in favor of a significant association between dysbiosis, neuroinflammation and neurodegeneration. Presently, the pathogenetic mechanisms triggered by molecules produced by the altered microbiota, also responsible for the onset and evolution of Alzheimer disease, will be described. Our attention will be focused on the role of astrocytes and microglia. Numerous studies have progressively demonstrated how these glial cells are important to ensure an adequate environment for neuronal activity in healthy conditions. Furthermore, it is becoming evident how both cell types can mediate the onset of neuroinflammation and lead to neurodegeneration when subjected to pathological stimuli. Based on this information, the role of the major microbiota products in shifting the activation profiles of astrocytes and microglia from a healthy to a diseased state will be discussed, focusing on Alzheimer disease pathogenesis.

scholarly journals Neuroplacentology in congenital heart disease: placental connections to neurodevelopmental outcomes

2021 ◽  
Author(s):  
Rachel L. Leon ◽  
Imran N. Mir ◽  
Christina L. Herrera ◽  
Kavita Sharma ◽  
Catherine Y. Spong ◽  
...  
Keyword(s):  
Brain Development ◽  
Congenital Heart ◽  
Fetal Brain ◽  
In Utero ◽  
Structure And Function ◽  
Brain Growth ◽  
Neurodevelopmental Outcomes ◽  
Fetal Brain Development ◽  
And Function

Abstract Children with congenital heart disease (CHD) are living longer due to effective medical and surgical management. However, the majority have neurodevelopmental delays or disorders. The role of the placenta in fetal brain development is unclear and is the focus of an emerging field known as neuroplacentology. In this review, we summarize neurodevelopmental outcomes in CHD and their brain imaging correlates both in utero and postnatally. We review differences in the structure and function of the placenta in pregnancies complicated by fetal CHD and introduce the concept of a placental inefficiency phenotype that occurs in severe forms of fetal CHD, characterized by a myriad of pathologies. We propose that in CHD placental dysfunction contributes to decreased fetal cerebral oxygen delivery resulting in poor brain growth, brain abnormalities, and impaired neurodevelopment. We conclude the review with key areas for future research in neuroplacentology in the fetal CHD population, including (1) differences in structure and function of the CHD placenta, (2) modifiable and nonmodifiable factors that impact the hemodynamic balance between placental and cerebral circulations, (3) interventions to improve placental function and protect brain development in utero, and (4) the role of genetic and epigenetic influences on the placenta–heart–brain connection. Impact Neuroplacentology seeks to understand placental connections to fetal brain development. In fetuses with CHD, brain growth abnormalities begin in utero. Placental microstructure as well as perfusion and function are abnormal in fetal CHD.

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