scholarly journals Differentiation of Crystal Cells, Gravity-Sensing Cells in the Placozoan Trichoplax adhaerens

2021 ◽  
Vol 9 (11) ◽  
pp. 1229
Author(s):  
Tatiana D. Mayorova
Keyword(s):  
Nervous System ◽  
Light Microscopy ◽  
Cell Types ◽  
Crystal Formation ◽  
Gravity Vector ◽  
Cell Type ◽  
Trichoplax Adhaerens ◽  
Biomineralization Process ◽  
Electron And Light Microscopy ◽  
Crystal Cells

Trichoplax adhaerens are simple animals with no nervous system, muscles or body axis. Nevertheless, Trichoplax demonstrate complex behaviors, including responses to the direction of the gravity vector. They have only six somatic cell types, and one of them, crystal cells, has been implicated in gravity reception. Multiple crystal cells are scattered near the rim of the pancake-shaped animal; each contains a cup-shaped nucleus and an intracellular crystal, which aligns its position according to the gravity force. Little is known about the development of any cell type in Trichoplax, which, in the laboratory, propagate exclusively by binary fission. Electron and light microscopy were used to investigate the stages by which crystal cells develop their mature phenotypes and distributions. Nascent crystal cells, identified by their possession of a small crystal, were located farther from the rim than mature crystal cells, indicating that crystal cells undergo displacement during maturation. They were elongated in shape and their nucleus was rounded. The crystal develops inside a vacuole flanked by multiple mitochondria, which, perhaps, supply molecules needed for the biomineralization process underlying crystal formation. This research sheds light on the development of unique cells with internal biomineralization and poses questions for further research.

scholarly journals A nervous system-specific subnuclear organelle in Caenorhabditis elegans

Genetics ◽  
2021 ◽  
Vol 217 (1) ◽  
Author(s):  
Kenneth Pham ◽  
Neda Masoudi ◽  
Eduardo Leyva-Díaz ◽  
Oliver Hobert
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Homeobox Gene ◽  
Cell Types ◽  
Nuclear Bodies ◽  
Loss Of Function ◽  
Cell Type ◽  
Cell Type Specificity ◽  
Splicing Speckles ◽  
Polycomb Bodies

Abstract We describe here phase-separated subnuclear organelles in the nematode Caenorhabditis elegans, which we term NUN (NUclear Nervous system-specific) bodies. Unlike other previously described subnuclear organelles, NUN bodies are highly cell type specific. In fully mature animals, 4–10 NUN bodies are observed exclusively in the nucleus of neuronal, glial and neuron-like cells, but not in other somatic cell types. Based on co-localization and genetic loss of function studies, NUN bodies are not related to other previously described subnuclear organelles, such as nucleoli, splicing speckles, paraspeckles, Polycomb bodies, promyelocytic leukemia bodies, gems, stress-induced nuclear bodies, or clastosomes. NUN bodies form immediately after cell cycle exit, before other signs of overt neuronal differentiation and are unaffected by the genetic elimination of transcription factors that control many other aspects of neuronal identity. In one unusual neuron class, the canal-associated neurons, NUN bodies remodel during larval development, and this remodeling depends on the Prd-type homeobox gene ceh-10. In conclusion, we have characterized here a novel subnuclear organelle whose cell type specificity poses the intriguing question of what biochemical process in the nucleus makes all nervous system-associated cells different from cells outside the nervous system.

scholarly journals A lineage-resolved molecular atlas of C. elegans embryogenesis at single-cell resolution

Science ◽  
2019 ◽  
Vol 365 (6459) ◽  
pp. eaax1971 ◽  
Author(s):  
Jonathan S. Packer ◽  
Qin Zhu ◽  
Chau Huynh ◽  
Priya Sivaramakrishnan ◽  
Elicia Preston ◽  
...  
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Single Cell ◽  
Molecular Basis ◽  
Cell Types ◽  
Embryonic Cells ◽  
Cell Type ◽  
C Elegans ◽  
Exact Position ◽  
Sister Cells

Caenorhabditis elegans is an animal with few cells but a wide diversity of cell types. In this study, we characterize the molecular basis for their specification by profiling the transcriptomes of 86,024 single embryonic cells. We identify 502 terminal and preterminal cell types, mapping most single-cell transcriptomes to their exact position in C. elegans’ invariant lineage. Using these annotations, we find that (i) the correlation between a cell’s lineage and its transcriptome increases from middle to late gastrulation, then falls substantially as cells in the nervous system and pharynx adopt their terminal fates; (ii) multilineage priming contributes to the differentiation of sister cells at dozens of lineage branches; and (iii) most distinct lineages that produce the same anatomical cell type converge to a homogenous transcriptomic state.

scholarly journals The Effect of Glucocorticoid and Glucocorticoid Receptor Interactions on Brain, Spinal Cord, and Glial Cell Plasticity

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Kathryn M. Madalena ◽  
Jessica K. Lerch
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Glucocorticoid Receptor ◽  
Cell Types ◽  
Cell Type ◽  
Cell Plasticity ◽  
Stress Injury ◽  
Receptor Interactions ◽  
Cell Type Specific ◽  
Adaptation And Learning

Stress, injury, and disease trigger glucocorticoid (GC) elevation. Elevated GCs bind to the ubiquitously expressed glucocorticoid receptor (GR). While GRs are in every cell in the nervous system, the expression level varies, suggesting that diverse cell types react differently to GR activation. Stress/GCs induce structural plasticity in neurons, Schwann cells, microglia, oligodendrocytes, and astrocytes as well as affect neurotransmission by changing the release and reuptake of glutamate. While general nervous system plasticity is essential for adaptation and learning and memory, stress-induced plasticity is often maladaptive and contributes to neuropsychiatric disorders and neuropathic pain. In this brief review, we describe the evidence that stress/GCs activate GR to promote cell type-specific changes in cellular plasticity throughout the nervous system.

scholarly journals Astrocyte-like glia-specific gene deathstar is crucial for normal development, adult locomotion and lifespan of male Drosophila

2019 ◽  
Author(s):  
Hadi Najafi ◽  
Kyle Wong ◽  
Woo Jae Kim
Keyword(s):  
Nervous System ◽  
Expression Pattern ◽  
Normal Development ◽  
Optic Lobe ◽  
Cell Types ◽  
Specific Gene ◽  
Cell Type ◽  
Specific Expression ◽  
Bioinformatical Analysis ◽  
Specific Expression Pattern

ABSTRACTDrosophila melanogaster is a proper model organism for studying the development and function of the nervous system. The Drosophila nervous system consists of distinct cell types with significant homologies to various cell types of more advanced organisms, including human. Among all cell types of the nervous system, astrocyte-like glia (ALG) have conserved functions to mammals and are essential for normal physiology and behaviours of the fly.In this study, we exploited the gene expression profile of single cells in Drosophila optic lobe to identify the genes with specific expression pattern in each cell type. Through a bioinformatical analysis of the data, a novel ALG-specific gene (here assigned as deathstar) was identified. Immunostaining of deathstar in the central nervous system (CNS) showed its presence in specific regions of Drosophila ventral nerve cord, which previously has been characterized as ALG cells. Consistent with the bioinformatical analysis, deathstar-related signals were overlapped with the signals of the previously-reported ALG marker, Eaat1, supporting its specific expression in ALG cells.At the physiological level, RNAi-mediated suppression of deathstar gene impeded the normal development of male flies without any effects on females. Cell type-specific expression of deathstar RNAi showed that deathstar gene affects locomotion behaviour and lifespan of D. melanogaster, in an ALG-specific manner.Taken together, we showed that bioinformatical analysis of a previously reported expression data of Drosophila optic lobe successfully predicted the ALG-specific expression pattern of deathstar gene. Moreover, it was consistent with the ALG-specific effects of this gene on locomotion and lifespan of D. melanogaster, in vivo.

scholarly journals Regulation of immunoreactive GAP-43 expression in rat cortical macroglia is cell type specific.

1990 ◽  
Vol 111 (1) ◽  
pp. 209-215 ◽  
Author(s):  
A da Cunha ◽  
L Vitković
Keyword(s):  
Nervous System ◽  
Developmental Regulation ◽  
Cell Types ◽  
Type I ◽  
Cell Type ◽  
System Type ◽  
The Central Nervous System ◽  
Cell Type Specific

Growth-associated protein 43 (GAP-43) is an abundant, intensely investigated membrane phosphoprotein of the nervous system (Benowitz, L.I., and A. Routtenberg. 1987. Trends Neurosci. 10:527-532; Skene, J. H. P. 1989. Annu. Rev. Neurosci. 12:127-156), with a hitherto unknown function. We have previously demonstrated that astrocytes, brain macroglial cells, contain GAP-43 (Steisslinger, H. W., V. J. Aloyo, and L. Vitković, 1987. Brain Res. 415:375-379; Vitković, L., H. W. Steisslinger, V. J. Aloyo, and M. Mersel. 1988. Proc. Natl. Acad. Sci. USA. 85:8296-8300; Vitković L., and M. Mersel. 1989. Metab. Brain Dis. 4:47-53). Results from double immunofluorescent labeling experiments presented here show that oligodendrocytes also contain GAP-43 immunoreactivity (GAP-43ir). Thus, all three macroglial cell types of the central nervous system (type I and type 2 astrocytes and oligodendrocytes) contain GAP-43. Whereas immunoreactive GAP-43 is expressed by progenitors of all macroglial cell types, the developmental regulation of its expression is cell type specific. Immunoreactive GAP-43 is downregulated in type 1 astrocytes, and constitutively expressed in both type 2 astrocytes and oligodendrocytes. These results may be relevant to potential function(s) of GAP-43.

scholarly journals Cell type-specific modulation of healthspan by Forkhead family transcription factors in the nervous system

2021 ◽  
Vol 118 (8) ◽  
pp. e2011491118 ◽  
Author(s):  
Ekin Bolukbasi ◽  
Nathaniel S. Woodling ◽  
Dobril K. Ivanov ◽  
Jennifer Adcott ◽  
Andrea Foley ◽  
...  
Keyword(s):  
Nervous System ◽  
Transcription Factors ◽  
Cell Types ◽  
Growth Factor Signaling ◽  
Cell Type ◽  
Model Of Alzheimer’S Disease ◽  
Distinct Cell ◽  
Evolutionarily Conserved ◽  
Cell Type Specific ◽  
Specific Mapping

Reduced activity of insulin/insulin-like growth factor signaling (IIS) increases healthy lifespan among diverse animal species. Downstream of IIS, multiple evolutionarily conserved transcription factors (TFs) are required; however, distinct TFs are likely responsible for these effects in different tissues. Here we have asked which TFs can extend healthy lifespan within distinct cell types of the adult nervous system in Drosophila. Starting from published single-cell transcriptomic data, we report that forkhead (FKH) is endogenously expressed in neurons, whereas forkhead-box-O (FOXO) is expressed in glial cells. Accordingly, we find that neuronal FKH and glial FOXO exert independent prolongevity effects. We have further explored the role of neuronal FKH in a model of Alzheimer’s disease-associated neuronal dysfunction, where we find that increased neuronal FKH preserves behavioral function and reduces ubiquitinated protein aggregation. Finally, using transcriptomic profiling, we identify Atg17, a member of the Atg1 autophagy initiation family, as one FKH-dependent target whose neuronal overexpression is sufficient to extend healthy lifespan. Taken together, our results underscore the importance of cell type-specific mapping of TF activity to preserve healthy function with age.

scholarly journals Hidden cell diversity in Placozoa: Ultrastructural Insights from Hoilungia hongkongensis

2020 ◽  
Author(s):  
Daria Y. Romanova ◽  
Frederique Varoqueaux ◽  
Jean Daraspe ◽  
Mikhail A. Nikitin ◽  
Michael Eitel ◽  
...  
Keyword(s):  
Cell Types ◽  
Lower Surface ◽  
Point Of View ◽  
Cell Type ◽  
Free Living ◽  
Trichoplax Adhaerens ◽  
Genetic Complexity ◽  
Cell Diversity ◽  
Cell Layers

AbstractFrom a morphological point of view, placozoans are among the most simple free-living animals. This enigmatic phylum is critical for our understanding of the evolution of animals and their cell types. Their millimeter-sized, disc-like bodies consist of only three cell layers that are shaped by roughly six major cell types. Placozoans lack muscle cells and neurons but are able to move using their ciliated lower surface and take up food in a highly coordinated manner. Intriguingly, the genome of Trichoplax adhaerens, the founding member of the enigmatic phylum, has disclosed a surprising level of genetic complexity. Moreover, recent molecular and functional investigations have uncovered a much larger, so-far hidden cell-type diversity. Here, we have extended the microanatomical characterization of a recently described placozoan species – Hoilungia hongkongensis. In H. hongkongensis, we recognized the established canonical three-layered placozoan body plan but also came across several morphologically distinct and potentially novel cell types, among them novel gland cells and “shiny spheres”-bearing cells at the upper epithelium. Thus, the diversity of cell types in placozoans is indeed higher than anticipated.

scholarly journals Coherent directed movement toward food modeled in Trichoplax, a ciliated animal lacking a nervous system

2019 ◽  
Vol 116 (18) ◽  
pp. 8901-8908 ◽  
Author(s):  
Carolyn L. Smith ◽  
Thomas S. Reese ◽  
Tzipe Govezensky ◽  
Rafael A. Barrio
Keyword(s):  
Nervous System ◽  
Epithelial Cells ◽  
Cell Types ◽  
Lower Surface ◽  
Marine Animal ◽  
Directed Movement ◽  
Trichoplax Adhaerens ◽  
Modeling Behavior ◽  
Multicellular Organisms ◽  
Ciliated Epithelial Cells

Trichoplax adhaerens is a small, ciliated marine animal that glides on surfaces grazing upon algae, which it digests externally. It has no muscles or nervous system and only six cell types, all but two of which are embedded in its epithelium. The epithelial cells are joined by apical adherens junctions; neither tight junctions nor gap junctions are present. Monociliated epithelial cells on the lower surface propel gliding. The cilia beat regularly, but asynchronously, and transiently contact the substrate with each stroke. The animal moves in random directions in the absence of food. We show here that it exhibits chemotaxis, moving preferentially toward algae embedded in a disk of agar. We present a mathematical model to explain how coherent, directional movements could arise from the collective actions of a set of ciliated epithelial cells, each independently sensing and responding to a chemoattractant gradient. The model incorporates realistic values for viscoelastic properties of cells and produces coordinated movements and changes in body shape that resemble the actual movements of the animal. The model demonstrates that an animal can move coherently in search of food without any need for chemical signaling between cells and introduces a different approach to modeling behavior in primitive multicellular organisms.

Isolation of radial glial cells by fluorescent-activated cell sorting reveals a neuronal lineage

Development ◽  
2000 ◽  
Vol 127 (24) ◽  
pp. 5253-5263 ◽  
Author(s):  
P. Malatesta ◽  
E. Hartfuss ◽  
M. Gotz
Keyword(s):  
Nervous System ◽  
Glial Cells ◽  
Cell Sorting ◽  
Cell Types ◽  
Cell Type ◽  
Radial Glial Cells ◽  
Neuronal Precursors ◽  
Neuronal Lineage ◽  
Radial Glial ◽  
Glial Lineage

The developing central nervous system of vertebrates contains an abundant cell type designated radial glial cells. These cells are known as guiding cables for migrating neurons, while their role as precursor cells is less clear. Since radial glial cells express a variety of astroglial characteristics and differentiate as astrocytes after completing their guidance function, they have been considered as part of the glial lineage. Using fluorescence-activated cell sorting, we show here that radial glial cells also are neuronal precursors and only later, after neurogenesis, do they shift towards an exclusive generation of astrocytes. These results thus demonstrate a novel function for radial glial cells, namely their ability to generate two major cell types found in the nervous system, neurons and astrocytes.

Dissecting the temporal requirements for homeotic gene function

Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1983-1995 ◽  
Author(s):  
J. Castelli-Gair ◽  
S. Greig ◽  
G. Micklem ◽  
M. Akam
Keyword(s):  
Gene Expression ◽  
Nervous System ◽  
Gene Function ◽  
Cell Types ◽  
Homeotic Gene ◽  
Homeotic Genes ◽  
Bithorax Complex ◽  
Cell Type ◽  
Homeotic Gene Expression

Homeotic genes confer identity to the different segments of Drosophila. These genes are expressed in many cell types over long periods of time. To determine when the homeotic genes are required for specific developmental events we have expressed the Ultrabithorax, abdominal-A and Abdominal-Bm proteins at different times during development using the GAL4 targeting technique. We find that early transient homeotic gene expression has no lasting effects on the differentiation of the larval epidermis, but it switches the fate of other cell types irreversibly (e.g. the spiracle primordia). We describe one cell type in the peripheral nervous system that makes sequential, independent responses to homeotic gene expression. We also provide evidence that supports the hypothesis of in vivo competition between the bithorax complex proteins for the regulation of their down-stream targets.

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