Clinically Relevant Concentrations of Propofol but Not Midazolam Alter In Vitro  Dendritic Development of Isolated γ-Aminobutyric Acid-positive Interneurons

Background Recent laboratory studies showed that exposure to supraclinical concentrations of propofol can induce cell death of immature neurons. However, no data are available regarding the effects of clinically relevant concentrations of this agent on neuronal development. The authors addressed this issue by evaluating the effect of propofol on dendritic growth and arbor expansion of developing gamma-aminobutyric acid-positive (GABAergic) interneurons. Methods Immature neuroblasts were isolated from the newborn rat subventricular zone and differentiated into GABAergic interneurons in culture. In addition to cell death, the effects of increasing concentrations and durations of propofol exposure on neuronal dendritic development were evaluated using the following morphologic parameters: total dendritic length, primary dendrites, branching point, and Scholl analysis. Results The authors demonstrate that propofol induced cell death of GABAergic neurons at concentrations of 50 microg/ml or greater. As little as 1 microg/ml propofol significantly altered several aspects of dendritic development, and as little as 4 h of exposure to this agent resulted in a persistent decrease in dendritic growth. In contrast, application of midazolam did not affect neuronal development. Conclusion Short-term exposure of immature developing GABAergic neurons to clinically relevant concentrations of propofol can induce long-term changes in dendritic arbor development. These results suggest that propofol anesthesia during central nervous system development could interfere with the molecular mechanisms driving the differentiation of GABAergic neurons and thus could potentially lead to impairment of neural networks.

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Molecular mechanisms of cell death in neurological diseases

Cell Death and Differentiation ◽

10.1038/s41418-021-00814-y ◽

2021 ◽

Author(s):

Diane Moujalled ◽

Andreas Strasser ◽

Jeffrey R. Liddell

Keyword(s):

Cell Death ◽

Neurodegenerative Diseases ◽

Molecular Mechanisms ◽

Neuronal Development ◽

Neurological Diseases ◽

Treatment Strategies ◽

Current Treatment ◽

Response To Therapy ◽

Signalling Cascades ◽

The Brain

AbstractTightly orchestrated programmed cell death (PCD) signalling events occur during normal neuronal development in a spatially and temporally restricted manner to establish the neural architecture and shaping the CNS. Abnormalities in PCD signalling cascades, such as apoptosis, necroptosis, pyroptosis, ferroptosis, and cell death associated with autophagy as well as in unprogrammed necrosis can be observed in the pathogenesis of various neurological diseases. These cell deaths can be activated in response to various forms of cellular stress (exerted by intracellular or extracellular stimuli) and inflammatory processes. Aberrant activation of PCD pathways is a common feature in neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease, resulting in unwanted loss of neuronal cells and function. Conversely, inactivation of PCD is thought to contribute to the development of brain cancers and to impact their response to therapy. For many neurodegenerative diseases and brain cancers current treatment strategies have only modest effect, engendering the need for investigations into the origins of these diseases. With many diseases of the brain displaying aberrations in PCD pathways, it appears that agents that can either inhibit or induce PCD may be critical components of future therapeutic strategies. The development of such therapies will have to be guided by preclinical studies in animal models that faithfully mimic the human disease. In this review, we briefly describe PCD and unprogrammed cell death processes and the roles they play in contributing to neurodegenerative diseases or tumorigenesis in the brain. We also discuss the interplay between distinct cell death signalling cascades and disease pathogenesis and describe pharmacological agents targeting key players in the cell death signalling pathways that have progressed through to clinical trials.

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Multiple Roles of RNA Regulatory Factors in Neuronal Development and Function in C. elegans

The Oxford Handbook of Neuronal Protein Synthesis ◽

10.1093/oxfordhb/9780190686307.013.26 ◽

2020 ◽

Author(s):

Matthew G. Andrusiak ◽

Yishi Jin

Keyword(s):

Nervous System ◽

Cell Biology ◽

Molecular Mechanisms ◽

Neuronal Development ◽

Rna Binding ◽

Rna Binding Proteins ◽

Model Organism ◽

Nervous System Development ◽

Forward Genetics ◽

C Elegans

Recent evidence has highlighted the dynamic nature of mRNA regulation, particularly in the nervous system, from complex pre-mRNA processing to long-range transport and long-term storage of mature mRNAs. In accordance with the importance for mRNA-mediated regulation of nervous system development and maintenance, various mutations in RNA-binding proteins are associated with a range of human disorders. C. elegans express many RNA-binding factors that have human orthologs and perform similar biochemical functions. This chapter focuses on the research using C. elegans to dissect molecular mechanisms involving mRNA-mediated pathways. It highlights the key approaches and findings that integrate genetic and genomic studies in the nervous system. The analyses of genetic mutants, primarily using forward genetics, offer functional insights for genes important for neuronal development, synaptic transmission, and neuronal repair. In combination with single-neuron cell biology and cell-type genomics, the knowledge learned from this model organism has continued to lead to ground-breaking discoveries.

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The gamma-Protocadherins regulate the survival of GABAergic interneurons during developmentally-regulated cell death

10.1101/2020.01.15.908087 ◽

2020 ◽

Cited By ~ 2

Author(s):

Candace H. Carriere ◽

Anson D. Sing ◽

Wendy Xueyi Wang ◽

Brian E. Jones ◽

Yohan Yee ◽

...

Keyword(s):

Cell Death ◽

Molecular Mechanisms ◽

Brain Regions ◽

Inhibitory Neurons ◽

Motor Deficits ◽

Gabaergic Interneuron ◽

Gabaergic Interneurons ◽

Developmentally Regulated ◽

Regulated Cell Death ◽

Inhibitory Networks

SUMMARYInhibitory interneurons integrate into developing circuits in specific ratios and distributions. In the cortex, the formation of inhibitory networks occurs concurrently with the apoptotic elimination of a third of GABAergic interneurons. The molecular mechanisms that select GABAergic interneurons to survive or die are unknown. Here we report that the clustered Protocadherins regulate GABAergic cell survival in the developing brain. Deletion of the Pcdh-gamma genes (Pcdhgs) from GABAergic neurons in mice causes a severe loss of inhibitory neurons in multiple brain regions and results in motor deficits and seizure activities. By focusing on the neocortex and cerebellar cortex, we demonstrate that GABAergic interneuron loss results from elevated apoptosis during the postnatal wave of Bax-dependent programmed cell death. Pro-survival AKT signals are reduced in Pcdhg-deficient interneurons, diminishing the intrinsic capacity of interneurons to compete and incorporate into developing networks. We propose that the Pcdhgs mediate selective GABAergic interneuron survival to contribute to the formation of balanced inhibitory networks.

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NF-κB-c-REL impairment drives human stem cells into the oligodendroglial fate

10.1101/664060 ◽

2019 ◽

Author(s):

Lucia M Ruiz-Perera ◽

Johannes FW Greiner ◽

Christian Kaltschmidt ◽

Barbara Kaltschmidt

Keyword(s):

Stem Cells ◽

Neuronal Differentiation ◽

Molecular Mechanisms ◽

Neuronal Development ◽

System Development ◽

Nervous System Development ◽

Human Stem Cells ◽

Human Neural Stem Cells ◽

Transcription Factor Nuclear Factor

AbstractMolecular mechanisms underlying fate decisions of human neural stem cells (NSCs) between neurogenesis and gliogenesis are critical during neuronal development and progression of neurodegenerative diseases. Despite its crucial role in murine nervous system development, the potential role of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-κB) in fate shifts of human stem cells is poorly understood.Facing this challenge, we demonstrate here that NF-κB-c-REL drives glutamatergic differentiation of adult human stem cells, while its impairment results in a shift towards the oligodendroglial fate. We particularly observed an opposing balance switch from NF-κB-RELB/p52 to NF-κB-c-REL during early neuronal differentiation of NSCs originating from neural crest-derived stem cells. Exposure of differentiating human NSCs to the c-REL inhibiting approved drug pentoxifylline (PTXF) resulted in elevated levels of cell death and significantly decreased amounts of NF200+/VGLUT2+ neurons. PTXF-mediated inhibition of c-REL further drove human NSCs into the oligodendrocyte fate, as demonstrated by a complete switch to OLIG2+/O4+ oligodendrocytes, which also showed PDGFRα, NG2 and MBP transcripts.In summary, we present here a novel human cellular model of neuronal differentiation with an essential role of NF-κB-c-REL in fate choice between neurogenesis and oligodendrogenesis potentially relevant for multiple sclerosis and schizophrenia.

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Progress in understanding the role of lncRNA in programmed cell death

Cell Death Discovery ◽

10.1038/s41420-021-00407-1 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Na Jiang ◽

Xiaoyu Zhang ◽

Xuejun Gu ◽

Xiaozhuang Li ◽

Lei Shang

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Molecular Mechanisms ◽

Membrane Receptors ◽

Gene Expressions ◽

Apoptosis Pathway ◽

Stem Cell Pluripotency ◽

Extrinsic Apoptosis ◽

Related Proteins ◽

Cycle Regulation

AbstractLong non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides but not translated into proteins. LncRNAs regulate gene expressions at multiple levels, such as chromatin, transcription, and post-transcription. Further, lncRNAs participate in various biological processes such as cell differentiation, cell cycle regulation, and maintenance of stem cell pluripotency. We have previously reported that lncRNAs are closely related to programmed cell death (PCD), which includes apoptosis, autophagy, necroptosis, and ferroptosis. Overexpression of lncRNA can suppress the extrinsic apoptosis pathway by downregulating of membrane receptors and protect tumor cells by inhibiting the expression of necroptosis-related proteins. Some lncRNAs can also act as competitive endogenous RNA to prevent oxidation, thereby inhibiting ferroptosis, while some are known to activate autophagy. The relationship between lncRNA and PCD has promising implications in clinical research, and reports have highlighted this relationship in various cancers such as non-small cell lung cancer and gastric cancer. This review systematically summarizes the advances in the understanding of the molecular mechanisms through which lncRNAs impact PCD.

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Molecular pathology associated with altered synaptic transcriptome in the dorsolateral prefrontal cortex of depressed subjects

Translational Psychiatry ◽

10.1038/s41398-020-01159-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yuta Yoshino ◽

Bhaskar Roy ◽

Nilesh Kumar ◽

M. Shahid Mukhtar ◽

Yogesh Dwivedi

Keyword(s):

Gene Expression ◽

Cell Death ◽

Prefrontal Cortex ◽

Dorsolateral Prefrontal Cortex ◽

Gene Network ◽

Nervous System Development ◽

Network Analyses ◽

Dorsolateral Prefrontal ◽

Total Fraction ◽

Transcriptomic Changes

AbstractDisrupted synaptic plasticity is the hallmark of major depressive disorder (MDD), with accompanying changes at the molecular and cellular levels. Often, the maladaptive molecular changes at the synapse are the result of global transcriptional reprogramming dictated by activity-dependent synaptic modulation. Thus far, no study has directly studied the transcriptome-wide expression changes locally at the synapse in MDD brain. Here, we have examined altered synaptic transcriptomics and their functional relevance in MDD with a focus on the dorsolateral prefrontal cortex (dlPFC). RNA was isolated from total fraction and purified synaptosomes of dlPFC from well-matched 15 non-psychiatric controls and 15 MDD subjects. Transcriptomic changes in synaptic and total fractions were detected by next-generation RNA-sequencing (NGS) and analyzed independently. The ratio of synaptic/total fraction was estimated to evaluate a shift in gene expression ratio in MDD subjects. Bioinformatics and network analyses were used to determine the biological relevance of transcriptomic changes in both total and synaptic fractions based on gene–gene network, gene ontology (GO), and pathway prediction algorithms. A total of 14,005 genes were detected in total fraction. A total of 104 genes were differentially regulated (73 upregulated and 31 downregulated) in MDD group based on 1.3-fold change threshold and p < 0.05 criteria. In synaptosomes, out of 13,236 detectable genes, 234 were upregulated and 60 were downregulated (>1.3-fold, p < 0.05). Several of these altered genes were validated independently by a quantitative polymerase chain reaction (qPCR). GO revealed an association with immune system processes and cell death. Moreover, a cluster of genes belonged to the nervous system development, and psychological disorders were discovered using gene–gene network analysis. The ratio of synaptic/total fraction showed a shift in expression of 119 genes in MDD subjects, which were primarily associated with neuroinflammation, interleukin signaling, and cell death. Our results suggest not only large-scale gene expression changes in synaptosomes, but also a shift in the expression of genes from total to synaptic fractions of dlPFC of MDD subjects with their potential role in immunomodulation and cell death. Our findings provide new insights into the understanding of transcriptomic regulation at the synapse and their possible role in MDD pathogenesis.

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Zebrafish Models of Autosomal Recessive Ataxias

Cells ◽

10.3390/cells10040836 ◽

2021 ◽

Vol 10 (4) ◽

pp. 836

Author(s):

Ana Quelle-Regaldie ◽

Daniel Sobrido-Cameán ◽

Antón Barreiro-Iglesias ◽

María Jesús Sobrido ◽

Laura Sánchez

Keyword(s):

Animal Models ◽

Autosomal Recessive ◽

Molecular Mechanisms ◽

System Development ◽

Rapid Development ◽

Nervous System Development ◽

Central Nervous System Development ◽

Cellular Processes ◽

Recessive Disorders

Autosomal recessive ataxias are much less well studied than autosomal dominant ataxias and there are no clearly defined systems to classify them. Autosomal recessive ataxias, which are characterized by neuronal and multisystemic features, have significant overlapping symptoms with other complex multisystemic recessive disorders. The generation of animal models of neurodegenerative disorders increases our knowledge of their cellular and molecular mechanisms and helps in the search for new therapies. Among animal models, the zebrafish, which shares 70% of its genome with humans, offer the advantages of being small in size and demonstrating rapid development, making them optimal for high throughput drug and genetic screening. Furthermore, embryo and larval transparency allows to visualize cellular processes and central nervous system development in vivo. In this review, we discuss the contributions of zebrafish models to the study of autosomal recessive ataxias characteristic phenotypes, behavior, and gene function, in addition to commenting on possible treatments found in these models. Most of the zebrafish models generated to date recapitulate the main features of recessive ataxias.

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Fibrillar α-synuclein induces neurotoxic astrocyte activation via RIP kinase signaling and NF-κB

Cell Death and Disease ◽

10.1038/s41419-021-04049-0 ◽

2021 ◽

Vol 12 (8) ◽

Author(s):

Tsui-Wen Chou ◽

Nydia P. Chang ◽

Medha Krishnagiri ◽

Aisha P. Patel ◽

Marissa Lindman ◽

...

Keyword(s):

Cell Death ◽

Cell Biology ◽

Molecular Mechanisms ◽

Neurodegenerative Disorder ◽

Neuronal Cell ◽

Dopamine Neurons ◽

Functional Markers ◽

Kinase Signaling ◽

Astrocyte Activation ◽

Transcriptional Responses

AbstractParkinson’s disease (PD) is a neurodegenerative disorder characterized by the death of midbrain dopamine neurons. The pathogenesis of PD is poorly understood, though misfolded and/or aggregated forms of the protein α-synuclein have been implicated in several neurodegenerative disease processes, including neuroinflammation and astrocyte activation. Astrocytes in the midbrain play complex roles during PD, initiating both harmful and protective processes that vary over the course of the disease. However, despite their significant regulatory roles during neurodegeneration, the cellular and molecular mechanisms that promote pathogenic astrocyte activity remain mysterious. Here, we show that α-synuclein preformed fibrils (PFFs) induce pathogenic activation of human midbrain astrocytes, marked by inflammatory transcriptional responses, downregulation of phagocytic function, and conferral of neurotoxic activity. These effects required the necroptotic kinases RIPK1 and RIPK3, but were independent of MLKL and necroptosis. Instead, both transcriptional and functional markers of astrocyte activation occurred via RIPK-dependent activation of NF-κB signaling. Our study identifies a previously unknown function for α-synuclein in promoting neurotoxic astrocyte activation, as well as new cell death-independent roles for RIP kinase signaling in the regulation of glial cell biology and neuroinflammation. Together, these findings highlight previously unappreciated molecular mechanisms of pathologic astrocyte activation and neuronal cell death with implications for Parkinsonian neurodegeneration.

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LONP1 and ClpP cooperatively regulate mitochondrial proteostasis for cancer cell survival

Oncogenesis ◽

10.1038/s41389-021-00306-1 ◽

2021 ◽

Vol 10 (2) ◽

Author(s):

Yu Geon Lee ◽

Hui Won Kim ◽

Yeji Nam ◽

Kyeong Jin Shin ◽

Yu Jin Lee ◽

...

Keyword(s):

Cell Death ◽

Cell Growth ◽

Cell Survival ◽

Cancer Cell ◽

Stress Responses ◽

Molecular Mechanisms ◽

Tca Cycle ◽

Mitochondrial Matrix ◽

Mitochondrial Functions ◽

Cancer Cell Survival

AbstractMitochondrial proteases are key components in mitochondrial stress responses that maintain proteostasis and mitochondrial integrity in harsh environmental conditions, which leads to the acquisition of aggressive phenotypes, including chemoresistance and metastasis. However, the molecular mechanisms and exact role of mitochondrial proteases in cancer remain largely unexplored. Here, we identified functional crosstalk between LONP1 and ClpP, which are two mitochondrial matrix proteases that cooperate to attenuate proteotoxic stress and protect mitochondrial functions for cancer cell survival. LONP1 and ClpP genes closely localized on chromosome 19 and were co-expressed at high levels in most human cancers. Depletion of both genes synergistically attenuated cancer cell growth and induced cell death due to impaired mitochondrial functions and increased oxidative stress. Using mitochondrial matrix proteomic analysis with an engineered peroxidase (APEX)-mediated proximity biotinylation method, we identified the specific target substrates of these proteases, which were crucial components of mitochondrial functions, including oxidative phosphorylation, the TCA cycle, and amino acid and lipid metabolism. Furthermore, we found that LONP1 and ClpP shared many substrates, including serine hydroxymethyltransferase 2 (SHMT2). Inhibition of both LONP1 and ClpP additively increased the amount of unfolded SHMT2 protein and enhanced sensitivity to SHMT2 inhibitor, resulting in significantly reduced cell growth and increased cell death under metabolic stress. Additionally, prostate cancer patients with higher LONP1 and ClpP expression exhibited poorer survival. These results suggest that interventions targeting the mitochondrial proteostasis network via LONP1 and ClpP could be potential therapeutic strategies for cancer.

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Gene regulatory networks controlling differentiation, survival, and diversification of hypothalamic Lhx6-expressing GABAergic neurons

Communications Biology ◽

10.1038/s42003-020-01616-7 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Dong Won Kim ◽

Kai Liu ◽

Zoe Qianyi Wang ◽

Yi Stephanie Zhang ◽

Abhijith Bathini ◽

...

Keyword(s):

Cortical Neurons ◽

Regulatory Networks ◽

Molecular Mechanisms ◽

Gabaergic Neurons ◽

Zona Incerta ◽

Long Distance ◽

Hypothalamic Neurons ◽

Cortical Interneuron ◽

Tangential Migration ◽

Innate Behaviors

AbstractGABAergic neurons of the hypothalamus regulate many innate behaviors, but little is known about the mechanisms that control their development. We previously identified hypothalamic neurons that express the LIM homeodomain transcription factor Lhx6, a master regulator of cortical interneuron development, as sleep-promoting. In contrast to telencephalic interneurons, hypothalamic Lhx6 neurons do not undergo long-distance tangential migration and do not express cortical interneuronal markers such as Pvalb. Here, we show that Lhx6 is necessary for the survival of hypothalamic neurons. Dlx1/2, Nkx2-2, and Nkx2-1 are each required for specification of spatially distinct subsets of hypothalamic Lhx6 neurons, and that Nkx2-2+/Lhx6+ neurons of the zona incerta are responsive to sleep pressure. We further identify multiple neuropeptides that are enriched in spatially segregated subsets of hypothalamic Lhx6 neurons, and that are distinct from those seen in cortical neurons. These findings identify common and divergent molecular mechanisms by which Lhx6 controls the development of GABAergic neurons in the hypothalamus.

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