scholarly journals The ciliary gene INPP5E confers dorsal telencephalic identity to human cortical organoids by negatively regulating Sonic Hedgehog signalling

2021 ◽  
Author(s):  
Leah Schembs ◽  
Ariane Willems ◽  
Kerstin Hasenpusch-Theil ◽  
James D Cooper ◽  
Katie Whiting ◽  
...  
Keyword(s):  
Neurodevelopmental Disorders ◽  
Primary Cilia ◽  
Cell Types ◽  
Negative Regulator ◽  
Apical Surface ◽  
Radial Glial Cells ◽  
Intracellular Signalling Pathways ◽  
Radial Glial ◽  
Sonic Hedgehog Signalling

Defects in primary cilia, cellular antennas that controls multiple intracellular signalling pathways, underlie several neurodevelopmental disorders, but how cilia control essential steps in human brain formation remains elusive. Here, we show that cilia are present on the apical surface of radial glial cells in human foetal forebrain. Interfering with cilia signalling in human organoids by mutating the INPP5E gene leads to the formation of ventral telencephalic cell types instead of cortical progenitors and neurons. INPP5E mutant organoids also showed increased SHH signalling and cyclopamine treatment partially rescued this ventralisation. In addition, ciliary expression of SMO was increased and the integrity of the transition zone was compromised. Overall, these findings establish the importance of primary cilia for dorsal/ventral patterning in human corticogenesis, indicate a tissue specific role of INPP5E as a negative regulator of SHH signalling and have implications for the emerging roles of cilia in the pathogenesis of neurodevelopmental disorders.

scholarly journals A transient role of primary cilia in controlling direct versus indirect neurogenesis in the developing cerebral cortex

2020 ◽  
Author(s):  
Kerstin Hasenpusch-Theil ◽  
Christine Laclef ◽  
Matt Colligan ◽  
Eamon Fitzgerald ◽  
Katherine Howe ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Glial Cells ◽  
Primary Cilia ◽  
Newborn Mice ◽  
Radial Glial Cells ◽  
Radial Glial ◽  
Neuronal Subtype ◽  
Layer V ◽  
Mtor Signalling

ABSTRACTDuring the development of the cerebral cortex, neurons are generated directly from radial glial cells or indirectly via basal progenitors. The balance between these division modes determines the number and types of neurons formed in the cortex thereby affecting cortical functioning. Here, we investigate the role of primary cilia in this process. We show that a mutation in the ciliary gene Inpp5e leads to a transient increase in direct neurogenesis and subsequently to an overproduction of layer V neurons in newborn mice. Loss of Inpp5e also affects ciliary structure coinciding with increased Akt and mTOR signalling and reduced Gli3 repressor levels. Genetically re-storing Gli3 repressor rescues the decreased indirect neurogenesis in Inpp5e mutants. Overall, our analyses reveal how primary cilia determine neuronal subtype composition of the cortex by controlling direct vs indirect neurogenesis. These findings have implications for understanding cortical malformations in ciliopathies with INPP5E mutations.

scholarly journals A transient role of the ciliary gene Inpp5e in controlling direct versus indirect neurogenesis in cortical development

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Kerstin Hasenpusch-Theil ◽  
Christine Laclef ◽  
Matt Colligan ◽  
Eamon Fitzgerald ◽  
Katherine Howe ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Glial Cells ◽  
Primary Cilia ◽  
Cortical Development ◽  
Newborn Mice ◽  
Radial Glial Cells ◽  
Radial Glial ◽  
Neuronal Subtype ◽  
Layer V

During the development of the cerebral cortex, neurons are generated directly from radial glial cells or indirectly via basal progenitors. The balance between these division modes determines the number and types of neurons formed in the cortex thereby affecting cortical functioning. Here, we investigate the role of primary cilia in controlling the decision between forming neurons directly or indirectly. We show that a mutation in the ciliary gene Inpp5e leads to a transient increase in direct neurogenesis and subsequently to an overproduction of layer V neurons in newborn mice. Loss of Inpp5e also affects ciliary structure coinciding with reduced Gli3 repressor levels. Genetically restoring Gli3 repressor rescues the decreased indirect neurogenesis in Inpp5e mutants. Overall, our analyses reveal how primary cilia determine neuronal subtype composition of the cortex by controlling direct versus indirect neurogenesis. These findings have implications for understanding cortical malformations in ciliopathies with INPP5E mutations.

scholarly journals Centrin2 regulates CP110 removal in primary cilium formation

2015 ◽  
Vol 208 (6) ◽  
pp. 693-701 ◽  
Author(s):  
Suzanna L. Prosser ◽  
Ciaran G. Morrison
Keyword(s):  
Calcium Binding ◽  
Primary Cilia ◽  
Reverse Genetics ◽  
Cell Types ◽  
Serum Starvation ◽  
Basal Bodies ◽  
Cilium Formation ◽  
Cellular Quiescence ◽  
Retinal Pigmented Epithelial Cells

Primary cilia are antenna-like sensory microtubule structures that extend from basal bodies, plasma membrane–docked mother centrioles. Cellular quiescence potentiates ciliogenesis, but the regulation of basal body formation is not fully understood. We used reverse genetics to test the role of the small calcium-binding protein, centrin2, in ciliogenesis. Primary cilia arise in most cell types but have not been described in lymphocytes. We show here that serum starvation of transformed, cultured B and T cells caused primary ciliogenesis. Efficient ciliogenesis in chicken DT40 B lymphocytes required centrin2. We disrupted CETN2 in human retinal pigmented epithelial cells, and despite having intact centrioles, they were unable to make cilia upon serum starvation, showing abnormal localization of distal appendage proteins and failing to remove the ciliation inhibitor CP110. Knockdown of CP110 rescued ciliation in CETN2-deficient cells. Thus, centrin2 regulates primary ciliogenesis through controlling CP110 levels.

Polaris, a protein disrupted inorpkmutant mice, is required for assembly of renal cilium

2002 ◽  
Vol 282 (3) ◽  
pp. F541-F552 ◽  
Author(s):  
Bradley K. Yoder ◽  
Albert Tousson ◽  
Leigh Millican ◽  
John H. Wu ◽  
Charles E. Bugg ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Collecting Duct ◽  
Physiological Role ◽  
Duct Cell ◽  
Cystic Kidney Disease ◽  
Cystic Kidney ◽  
Apical Surface ◽  
Cystic Disease ◽  
Cortical Collecting Duct

Cilia are organelles that play diverse roles, from fluid movement to sensory reception. Polaris, a protein associated with cystic kidney disease in Tg737°rpkmice, functions in a ciliogenic pathway. Here, we explore the role of polaris in primary cilia on Madin-Darby canine kidney cells. The results indicate that polaris localization and solubility change dramatically during cilia formation. These changes correlate with the formation of basal bodies and large protein rafts at the apical surface of the epithelia. A cortical collecting duct cell line has been derived from mice with a mutation in the Tg737 gene. These cells do not develop normal cilia, which can be corrected by reexpression of the wild-type Tg737 gene. These data suggest that the primary cilia are important for normal renal function and/or development and that the ciliary defect may be a contributing factor to the cystic disease in Tg737°rpkmice. Further characterization of these cells will be important in elucidating the physiological role of renal cilia and in determining their relationship to cystic disease.

scholarly journals Primary cilium and glioblastoma

2018 ◽  
Vol 10 ◽  
pp. 175883591880116 ◽  
Author(s):  
María Álvarez-Satta ◽  
Ander Matheu
Keyword(s):  
Cancer Progression ◽  
Primary Cilium ◽  
Primary Cilia ◽  
Apical Surface ◽  
New Approach ◽  
Primary Brain Tumour ◽  
Tumorigenesis And Progression ◽  
Signalling Transduction ◽  
Abnormal Cilia

Glioblastoma (GBM) represents the most common, malignant and lethal primary brain tumour in adults. The primary cilium is a highly conserved and dynamic organelle that protrudes from the apical surface of virtually every type of mammalian cell. There is increasing evidence that abnormal cilia are involved in cancer progression, since primary cilia regulate cell cycle and signalling transduction. In this review, we summarize the role of primary cilium specifically with regard to GBM, where there is evidence postulating it as a critical mediator of GBM tumorigenesis and progression. This opens the way to the application of cilia-targeted therapies (‘ciliotherapy’) as a new approach in the fight against this devastating tumour.

Mutations affecting neurogenesis and brain morphology in the zebrafish, Danio rerio

Development ◽  
1996 ◽  
Vol 123 (1) ◽  
pp. 205-216 ◽  
Author(s):  
Y.J. Jiang ◽  
M. Brand ◽  
C.P. Heisenberg ◽  
D. Beuchle ◽  
M. Furutani-Seiki ◽  
...  
Keyword(s):  
Cell Types ◽  
Brain Morphology ◽  
Abnormal Development ◽  
Radial Glial Cells ◽  
Complementation Groups ◽  
Early Neurogenesis ◽  
Radial Glial ◽  
General Organization ◽  
Neurogenic Mutants ◽  
The Brain

In a screen for embryonic mutants in the zebrafish a large number of mutants were isolated with abnormal brain morphology. We describe here 26 mutants in 13 complementation groups that show abnormal development of large regions of the brain. Early neurogenesis is affected in white tail (wit). During segmentation stages, homozygous wit embryos display an irregularly formed neural keel, particularly in the hindbrain. Using a variety of molecular markers, a severe increase in the number of various early differentiating neurons can be demonstrated. In contrast, late differentiating neurons, radial glial cells and some nonneural cell types, such as the neural crest-derived melanoblasts, are much reduced. Somitogenesis appears delayed. In addition, very reduced numbers of melanophores are present posterior to the mid-trunk. The wit phenotype is reminiscent of neurogenic mutants in Drosophila, such as Notch or Delta. In mutant parachute (pac) embryos the general organization of the hindbrain is disturbed and many rounded cells accumulate loosely in the hindbrain and midbrain ventricles. Mutants in a group of 6 genes, snakehead(snk), natter (nat), otter (ott), fullbrain (ful), viper (vip) and white snake (wis) develop collapsed brain ventricles, before showing signs of general degeneration. atlantis (atl), big head (bid), wicked brain (win), scabland (sbd) and eisspalte (ele) mutants have different malformation of the brain folds. Some of them have transient phenotypes, and mutant individuals may grow up to adults.

scholarly journals Dentate gyrus development requires a cortical hem-derived astrocytic scaffold

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Alessia Caramello ◽  
Christophe Galichet ◽  
Karine Rizzoti ◽  
Robin Lovell-Badge
Keyword(s):  
Transcription Factors ◽  
Dentate Gyrus ◽  
Local Network ◽  
Radial Glial Cells ◽  
Neuronal Progenitor ◽  
Neuronal Progenitors ◽  
Radial Glial ◽  
Cortical Hem ◽  
Mouse Brain Development

During embryonic development, radial glial cells give rise to neurons, then to astrocytes following the gliogenic switch. Timely regulation of the switch, operated by several transcription factors, is fundamental for allowing coordinated interactions between neurons and glia. We deleted the gene for one such factor, SOX9, early during mouse brain development and observed a significantly compromised dentate gyrus (DG). We dissected the origin of the defect, targeting embryonic Sox9 deletion to either the DG neuronal progenitor domain or the adjacent cortical hem (CH). We identified in the latter previously uncharacterized ALDH1L1+ astrocytic progenitors, which form a fimbrial-specific glial scaffold necessary for neuronal progenitor migration towards the developing DG. Our results highlight an early crucial role of SOX9 for DG development through regulation of astroglial potential acquisition in the CH. Moreover, we illustrate how formation of a local network, amidst astrocytic and neuronal progenitors originating from adjacent domains, underlays brain morphogenesis.

scholarly journals Trp53 ablation fails to prevent microcephaly in mouse pallium with impaired minor intron splicing

Development ◽  
2021 ◽  
Author(s):  
Alisa K. White ◽  
Marybeth Baumgartner ◽  
Madisen F. Lee ◽  
Kyle D. Drake ◽  
Gabriela S. Aquino ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Intron Splicing ◽  
Mitotic Progression ◽  
Double Knockout ◽  
Radial Glial Cells ◽  
Radial Glial ◽  
A Minor ◽  
Cycle Regulation

Minor spliceosome inhibition due to mutations in RNU4ATAC are linked to primary microcephaly. Ablation of Rnu11, a minor spliceosome snRNA, inhibits the minor spliceosome in the developing mouse pallium, causing microcephaly. There, cell cycle defects and p53-mediated apoptosis in response to DNA damage resulted in loss of radial glial cells (RGCs), underpinning microcephaly. Here, we ablated Trp53 to block cell death in the Rnu11 cKO mice. We report that Trp53 ablation failed to prevent microcephaly in these double knockout (dKO) mice. We show that the transcriptome of the dKO pallium was closer to the control compared to the Rnu11 cKO. We find aberrant minor intron splicing in MIGs involved in cell cycle regulation, resulting in more severely impaired mitotic progression and cell cycle lengthening of RGCs in the dKO that was detected earlier than the Rnu11 cKO. Furthermore, we discover a potential role of p53 in causing DNA damage in the developing pallium, as detection of γH2aX+ was delayed in the dKO. Thus, we postulate that microcephaly in minor spliceosome-related diseases is primarily caused by cell cycle defects.

scholarly journals SETD2 negatively regulates cell size through its catalytic activity and SRI domain

2021 ◽  
Author(s):  
Thom M Molenaar ◽  
Eliza Mari Kwesi-Maliepaard ◽  
Joana Silva ◽  
Muddassir Malik ◽  
William J Faller ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Rna Polymerase Ii ◽  
Cell Size ◽  
Cell Function ◽  
Size Control ◽  
Cell Types ◽  
Negative Regulator ◽  
Cellular Functions ◽  
Global Protein Synthesis

Cell size varies between cell types but is tightly regulated by cell-intrinsic and extrinsic mechanisms. Cell-size control is important for cell function and changes in cell size are frequently observed in cancer cells. Here we uncover a non-canonical role of SETD2 in regulating cell size. SETD2 is a lysine methyltransferase and a tumor suppressor protein involved in transcription regulation, RNA processing and DNA repair. At the molecular level, SETD2 is best known for associating with RNA polymerase II through its Set2-Rbp1 interacting (SRI) domain and methylating histone H3 on lysine 36 (H3K36) during transcription. Although most of the cellular functions of SETD2 have been linked to this activity, several non-histone substrates of SETD2 have recently been identified, some of which have been linked to novel functions of SETD2 beyond chromatin regulation. Using multiple, independent perturbation strategies we identify SETD2 as a negative regulator of global protein synthesis rates and cell size. We provide evidence that this function is dependent on the catalytic activity of SETD2 but independent of H3K36 methylation. Paradoxically, ectopic overexpression of a decoy SRI domain also increased cell size, suggesting that the relevant substrate is engaged by SETD2 via its SRI domain. These data add a central role of SETD2 in regulating cellular physiology and warrant further studies on separating the different functions of SETD2 in cancer development.

scholarly journals Cell-Scale Modeling to Probe Mechanobiology during Early Cortical Development

2020 ◽  
Vol 3 ◽  
Author(s):  
Adam Lonnberg ◽  
Kara Garcia
Keyword(s):  
Glial Cells ◽  
Apical Surface ◽  
Cortical Folding ◽  
Radial Glial Cells ◽  
Scale Modeling ◽  
Modeling Software ◽  
Radial Glial ◽  
Radial Tension ◽  
Stochastic Production ◽  
Potential Impact

Background/Objective: During early cerebral cortex development, neurons form from proliferative glial cells near the ventricular (apical) surface, then migrate along radial glial scaffolds to the cortical surface. In species with wrinkled brains, the presence of basal radial glial cells (bRGCs), radial glial cells which have detached from the ventricular surface, is correlated to the process of gyrification. While mechanical forces are also involved in gyrus creation, the link between the mechanical and biological aspects of this process remains unelucidated. In this study, we hypothesized that radial tension may lead to the production of gyri via the intermediary creation of bRGCs.  Methods: To test this hypothesis, the cell-level modeling software CX3D was used to simulate a system in which radial tension acts on radial glial cells (RGCs), facilitating the semi-stochastic production of bRGCs during the process of neocortex development. The outcome of this model was contrasted with a control case in which bRGCs were not allowed to form, and the two models were compared based upon the presence of neurons on the basal surface.  Results: The production of bRGCs via tension corresponded to a significant increase in the presence of neurons on the pial surface, even if the total number of glial cells—and thus total number of neurons generated—remained constant. Additionally, the likelihood of neurons moving more basally was found to be significantly greater in the presence of bRGCs.  Conclusion and Potential Impact: These results were interpreted to be indications of early gyrus formation. Thus, this study showed that bRGCs—and, ultimately, gyri—may arise from mechanical tension, indicating a possible link between the biological and mechanical explanations of gyrus formation. By providing an alternative lens through which to understand cortical folding, this may have implications for future lines of inquiry, which may expand our understanding of neuro-pathologies associated with misfolding, such as autism and epilepsy. 

Sign in / Sign up

Export Citation Format

Share Document