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Munoz-Gualan AP, Güngör A, Cezayirli PC, Rahmanov S, Gurses ME, Puelles L, Türe U. Human Adapted Prosomeric Model: A Future for Brainstem Tumor Classification. Brain Res 2024; 1837:148961. [PMID: 38679312 DOI: 10.1016/j.brainres.2024.148961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 03/30/2024] [Accepted: 04/24/2024] [Indexed: 05/01/2024]
Abstract
This study reevaluates the conventional understanding of midbrain anatomy and neuroanatomical nomenclature in the context of recent genetic and anatomical discoveries. The authors assert that the midbrain should be viewed as an integral part of the forebrain due to shared genetic determinants and evolutionary lineage. The isthmo-mesencephalic boundary is recognized as a significant organizer for both the caudal midbrain and the isthmo-cerebellar area. The article adopts the prosomeric model, redefining the whole brain as neuromeres, offering a more precise depiction of brain development, including processes like proliferation, neurogenesis, cell migration, and differentiation. This shift in understanding challenges traditional definitions of the midbrain based on external brain morphology. The study also delves into the historical context of neuroanatomical models, including the columnar model proposed by Herrick in 1910, which has influenced our understanding of brain structure. Furthermore, the study has clinical implications, affecting neuroanatomy, neurodevelopmental studies, and the diagnosis and treatment of brain disorders. It emphasizes the need to integrate molecular research into human neuroanatomical studies and advocates for updating neuroanatomical terminology to reflect modern genetic and molecular insights. The authors propose two key revisions. First, we suggest reclassifying the isthmo-cerebellar prepontine region as part of the hindbrain, due to its role in cerebellar development and distinct location caudal to the genetically-defined midbrain. Second, we recommend redefining the anterior boundary of the genetically-defined midbrain to align with genetic markers. In conclusion, the authors highlight the importance of harmonizing neuroanatomical nomenclature with current scientific knowledge, promoting a more precise and informed understanding of brain structure, which is crucial for both research and clinical applications related to the human brain.
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Affiliation(s)
| | - Abuzer Güngör
- Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul, Turkey; Department of Neurosurgery, Istinye University, Istanbul, Turkey
| | - Phillip Cem Cezayirli
- Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul, Turkey; Haynes Neurosurgical Group, Birmingham, AL, United States
| | - Serdar Rahmanov
- Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul, Turkey
| | - Muhammet Enes Gurses
- Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul, Turkey; Department of Neurosurgery, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Luis Puelles
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia, Murcia, Spain; Institute of Biomedical Research of Murcia -IMIB, Virgen de la Arrixaca University Hospital, Murcia, Spain
| | - Uğur Türe
- Department of Neurosurgery, Yeditepe University School of Medicine, Istanbul, Turkey.
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2
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D’Gama PP, Jeong I, Nygård AM, Trinh AT, Yaksi E, Jurisch-Yaksi N. Ciliogenesis defects after neurulation impact brain development and neuronal activity in larval zebrafish. iScience 2024; 27:110078. [PMID: 38868197 PMCID: PMC11167523 DOI: 10.1016/j.isci.2024.110078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 03/06/2024] [Accepted: 05/19/2024] [Indexed: 06/14/2024] Open
Abstract
Cilia are slender, hair-like structures extending from cell surfaces and playing essential roles in diverse physiological processes. Within the nervous system, primary cilia contribute to signaling and sensory perception, while motile cilia facilitate cerebrospinal fluid flow. Here, we investigated the impact of ciliary loss on neural circuit development using a zebrafish line displaying ciliogenesis defects. We found that cilia defects after neurulation affect neurogenesis and brain morphology, especially in the cerebellum, and lead to altered gene expression profiles. Using whole brain calcium imaging, we measured reduced light-evoked and spontaneous neuronal activity in all brain regions. By shedding light on the intricate role of cilia in neural circuit formation and function in the zebrafish, our work highlights their evolutionary conserved role in the brain and sets the stage for future analysis of ciliopathy models.
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Affiliation(s)
- Percival P. D’Gama
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Erling Skalgssons gate 1, 7030 Trondheim, Norway
| | - Inyoung Jeong
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Erling Skalgssons gate 1, 7030 Trondheim, Norway
| | - Andreas Moe Nygård
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Erling Skalgssons gate 1, 7030 Trondheim, Norway
| | - Anh-Tuan Trinh
- Kavli Institute for Systems Neuroscience and Centre for Algorithms in the Cortex, Norwegian University of Science and Technology, Olav Kyrres Gate 9, 7030 Trondheim, Norway
| | - Emre Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Algorithms in the Cortex, Norwegian University of Science and Technology, Olav Kyrres Gate 9, 7030 Trondheim, Norway
- Koç University Research Center for Translational Medicine, Koç University School of Medicine, Davutpaşa Caddesi, No:4, Topkapı 34010, Istanbul, Turkey
| | - Nathalie Jurisch-Yaksi
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Erling Skalgssons gate 1, 7030 Trondheim, Norway
- Kavli Institute for Systems Neuroscience and Centre for Algorithms in the Cortex, Norwegian University of Science and Technology, Olav Kyrres Gate 9, 7030 Trondheim, Norway
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3
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Zhang P, Duan L, Ou Y, Ling Q, Cao L, Qian H, Zhang J, Wang J, Yuan X. The cerebellum and cognitive neural networks. Front Hum Neurosci 2023; 17:1197459. [PMID: 37576472 PMCID: PMC10416251 DOI: 10.3389/fnhum.2023.1197459] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/11/2023] [Indexed: 08/15/2023] Open
Abstract
Cognitive function represents a complex neurophysiological capacity of the human brain, encompassing a higher level of neural processing and integration. It is widely acknowledged that the cerebrum plays a commanding role in the regulation of cognitive functions. However, the specific role of the cerebellum in cognitive processes has become a subject of considerable scholarly intrigue. In 1998, Schmahmann first proposed the concept of "cognitive affective syndrome (CCAS)," linking cerebellar damage to cognitive and emotional impairments. Since then, a substantial body of literature has emerged, exploring the role of the cerebellum in cognitive neurological function. The cerebellum's adjacency to the cerebral cortex, brainstem, and spinal cord suggests that the cerebral-cerebellar network loops play a crucial role in the cerebellum's participation in cognitive neurological functions. In this review, we comprehensively examine the recent literature on the involvement of the cerebellum in cognitive functions from three perspectives: the cytological basis of the cerebellum and its anatomical functions, the cerebellum and cognitive functions, and Crossed cerebellar diaschisis. Our aim is to shed light on the role and mechanisms of the cerebellum in cognitive neurobrain networks.
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Affiliation(s)
- Pingshu Zhang
- Department of Neurology, Kailuan General Hospital, North China University of Technology, Tangshan, Hebei, China
- Key Laboratory of Neurobiological Function in Hebei Province, Tangshan, Hebei, China
| | - Liqin Duan
- Department of Neurology, Kailuan General Hospital, North China University of Technology, Tangshan, Hebei, China
- Key Laboratory of Neurobiological Function in Hebei Province, Tangshan, Hebei, China
| | - Ya Ou
- Department of Neurology, Kailuan General Hospital, North China University of Technology, Tangshan, Hebei, China
- Key Laboratory of Neurobiological Function in Hebei Province, Tangshan, Hebei, China
| | - Qirong Ling
- Key Laboratory of Neurobiological Function in Hebei Province, Tangshan, Hebei, China
| | - Lingyun Cao
- Key Laboratory of Neurobiological Function in Hebei Province, Tangshan, Hebei, China
| | - Hongchun Qian
- Key Laboratory of Neurobiological Function in Hebei Province, Tangshan, Hebei, China
| | - Jian Zhang
- Key Laboratory of Neurobiological Function in Hebei Province, Tangshan, Hebei, China
| | - Jing Wang
- Key Laboratory of Neurobiological Function in Hebei Province, Tangshan, Hebei, China
| | - Xiaodong Yuan
- Department of Neurology, Kailuan General Hospital, North China University of Technology, Tangshan, Hebei, China
- Key Laboratory of Neurobiological Function in Hebei Province, Tangshan, Hebei, China
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4
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Lin T, Sun Y. Arl13b promotes the proliferation, migration, osteogenesis, and mechanosensation of osteoblasts. Tissue Cell 2023; 82:102088. [PMID: 37058812 DOI: 10.1016/j.tice.2023.102088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/27/2023] [Accepted: 04/10/2023] [Indexed: 04/16/2023]
Abstract
Primary cilia are microtubule-based organelles presenting on the surface of most postmitotic mammalian cells. As being signaling hubs and sensory organelles, primary cilia can respond to mechanical and chemical stimuli from the extracellular environment. Arl13b (ADP-ribosylation factor-like 13B), an atypical Arf/Arl family GTPase, was identified in genetic screening as a protein essential for maintaining the integrity of cilia and neural tubes. Previous studies on Arl13b have mostly focused on its role in the development of neural tubes, polycystic kidneys, and tumors, but no role in bone patterns was described. This study reported the essential roles of Arl13b in bone formation and osteogenic differentiation. Arl13b was highly expressed in bone tissues and osteoblasts, positively correlated with osteogenic activity during bone development. Furthermore, Arl13b was essential for primary cilium maintenance and Hedgehog signaling activation in osteoblasts. Arl13b knockdown in osteoblasts decreased the length of primary cilia and the upregulated levels of Gli1, Smo, and Ptch1 upon Smo agonist treatment. Additionally, Arl13b knockdown inhibited cell proliferation and migration. Moreover, Arl13b mediated osteogenesis and cell mechanosensation. Cyclic tension strain upregulated the Arl13b expression. Arl13b knockdown suppressed osteogenesis and mitigated cyclic tension strain-induced osteogenesis. These results suggest that Arl13b have important roles in bone formation and mechanosensation.
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Affiliation(s)
- Tingting Lin
- Department of Implantology, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072, China
| | - Yao Sun
- Department of Implantology, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai 200072, China.
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Kolas V, Bandonil JSA, Wali N, Hsia KC, Shie JJ, Chung BC. A synthetic pregnenolone analog promotes microtubule dynamics and neural development. Cell Biosci 2022; 12:190. [PMID: 36456994 PMCID: PMC9717551 DOI: 10.1186/s13578-022-00923-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 11/03/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Pregnenolone (P5) is a neurosteroid that promotes microtubule polymerization. It also reduces stress and negative symptoms of schizophrenia, promotes memory, as well as recovery from spinal cord injury. P5 is the first substance in the steroid-synthetic pathway; it can be further metabolized into other steroids. Therefore, it is difficult to differentiate the roles of P5 versus its metabolites in the brain. To alleviate this problem, we synthesized and screened a series of non-metabolizable P5 derivatives for their ability to polymerize microtubules similar to P5. RESULTS We identified compound #43 (3-beta-pregnenolone acetate), which increased microtubule polymerization. We showed that compound #43 modified microtubule dynamics in live cells, increased neurite outgrowth and changed growth cone morphology in mouse cerebellar granule neuronal culture. Furthermore, compound #43 promoted the formation of stable microtubule tracks in zebrafish developing cerebellar axons. CONCLUSIONS We have developed compound #43, a nonmetabolized P5 analog, that recapitulates P5 functions in vivo and can be a new therapeutic candidate for the treatment of neurodevelopmental diseases.
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Affiliation(s)
- Viktoryia Kolas
- grid.28665.3f0000 0001 2287 1366Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan ,grid.38348.340000 0004 0532 0580Institute of Molecular and Cellular Biology, National Tsing-Hua University, Hsinchu, Taiwan
| | | | - Niaz Wali
- grid.28665.3f0000 0001 2287 1366Institute of Chemistry, Academia Sinica, Taipei, Taiwan ,grid.19188.390000 0004 0546 0241Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617 Taiwan ,grid.28665.3f0000 0001 2287 1366Chemical Biology and Molecular Biophysics, Taiwan International Graduate Program, (TIGP-CBMB) Academia Sinica, Taipei, 11529 Taiwan
| | - Kuo-Chiang Hsia
- grid.28665.3f0000 0001 2287 1366Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Jiun-Jie Shie
- grid.28665.3f0000 0001 2287 1366Institute of Chemistry, Academia Sinica, Taipei, Taiwan
| | - Bon-chu Chung
- grid.28665.3f0000 0001 2287 1366Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan ,grid.38348.340000 0004 0532 0580Institute of Molecular and Cellular Biology, National Tsing-Hua University, Hsinchu, Taiwan ,grid.254145.30000 0001 0083 6092Graduate Institute of Biomedical Sciences, Neuroscience and Brain Disease Center, China Medical University, Taichung, 404 Taiwan
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6
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Rusterholz TDS, Hofmann C, Bachmann-Gagescu R. Insights Gained From Zebrafish Models for the Ciliopathy Joubert Syndrome. Front Genet 2022; 13:939527. [PMID: 35846153 PMCID: PMC9280682 DOI: 10.3389/fgene.2022.939527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 05/26/2022] [Indexed: 12/04/2022] Open
Abstract
Cilia are quasi-ubiquitous microtubule-based sensory organelles, which play vital roles in signal transduction during development and cell homeostasis. Dysfunction of cilia leads to a group of Mendelian disorders called ciliopathies, divided into different diagnoses according to clinical phenotype constellation and genetic causes. Joubert syndrome (JBTS) is a prototypical ciliopathy defined by a diagnostic cerebellar and brain stem malformation termed the “Molar Tooth Sign” (MTS), in addition to which patients display variable combinations of typical ciliopathy phenotypes such as retinal dystrophy, fibrocystic renal disease, polydactyly or skeletal dystrophy. Like most ciliopathies, JBTS is genetically highly heterogeneous with ∼40 associated genes. Zebrafish are widely used to model ciliopathies given the high conservation of ciliary genes and the variety of specialized cilia types similar to humans. In this review, we compare different existing JBTS zebrafish models with each other and describe their contributions to our understanding of JBTS pathomechanism. We find that retinal dystrophy, which is the most investigated ciliopathy phenotype in zebrafish ciliopathy models, is caused by distinct mechanisms according to the affected gene. Beyond this, differences in phenotypes in other organs observed between different JBTS-mutant models suggest tissue-specific roles for proteins implicated in JBTS. Unfortunately, the lack of systematic assessment of ciliopathy phenotypes in the mutants described in the literature currently limits the conclusions that can be drawn from these comparisons. In the future, the numerous existing JBTS zebrafish models represent a valuable resource that can be leveraged in order to gain further insights into ciliary function, pathomechanisms underlying ciliopathy phenotypes and to develop treatment strategies using small molecules.
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Affiliation(s)
- Tamara D. S. Rusterholz
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
- Department of Molecular Life Sciences, University of Zurich, Zürich, Switzerland
| | - Claudia Hofmann
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
- Department of Molecular Life Sciences, University of Zurich, Zürich, Switzerland
| | - Ruxandra Bachmann-Gagescu
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
- Department of Molecular Life Sciences, University of Zurich, Zürich, Switzerland
- *Correspondence: Ruxandra Bachmann-Gagescu,
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7
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Wang SD, Wang X, Zhao Y, Xue BH, Wang XT, Chen YX, Zhang ZQ, Tian YR, Xie F, Qian LJ. Homocysteine-Induced Disturbances in DNA Methylation Contribute to Development of Stress-Associated Cognitive Decline in Rats. Neurosci Bull 2022; 38:887-900. [PMID: 35435568 PMCID: PMC9352847 DOI: 10.1007/s12264-022-00852-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 01/11/2022] [Indexed: 11/28/2022] Open
Abstract
Chronic stress is generally accepted as the main risk factor in the development of cognitive decline; however, the underlying mechanisms remain unclear. Previous data have demonstrated that the levels of homocysteine (Hcy) are significantly elevated in the plasma of stressed animals, which suggests that Hcy is associated with stress and cognitive decline. To test this hypothesis, we analyzed the cognitive function, plasma concentrations of Hcy, and brain-derived neurotropic factor (BDNF) levels in rats undergoing chronic unpredicted mild stress (CUMS). The results showed that decreased cognitive behavioral performance and decreased BDNF transcription and protein expression were correlated with hyperhomocysteinemia (HHcy) levels in stressed rats. Diet-induced HHcy mimicked the cognitive decline and BDNF downregulation in the same manner as CUMS, while Hcy reduction (by means of vitamin B complex supplements) alleviated the cognitive deficits and BDNF reduction in CUMS rats. Furthermore, we also found that both stress and HHcy disturbed the DNA methylation process in the brain and induced DNA hypermethylation in the BDNF promoter. In contrast, control of Hcy blocked BDNF promoter methylation and upregulated BDNF levels in the brain. These results imply the possibility of a causal role of Hcy in stress-induced cognitive decline. We also used ten-eleven translocation (TET1), an enzyme that induces DNA demethylation, to verify the involvement of Hcy and DNA methylation in the regulation of BDNF expression and the development of stress-related cognitive decline. The data showed that TET1-expressing viral injection into the hippocampus inhibited BDNF promoter methylation and significantly mitigated the cognitive decline in HHcy rats. Taken together, novel evidence from the present study suggests that Hcy is likely involved in chronic stress-induced BDNF reduction and related cognitive deficits. In addition, the negative side-effects of HHcy may be associated with Hcy-induced DNA hypermethylation in the BDNF promoter. The results also suggest the possibility of Hcy as a target for therapy and the potential value of vitamin B intake in preventing stress-induced cognitive decline.
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8
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Pollara L, Sottile V, Valente EM. Patient-derived cellular models of primary ciliopathies. J Med Genet 2022; 59:517-527. [DOI: 10.1136/jmedgenet-2021-108315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/21/2022] [Indexed: 11/09/2022]
Abstract
Primary ciliopathies are rare inherited disorders caused by structural or functional defects in the primary cilium, a subcellular organelle present on the surface of most cells. Primary ciliopathies show considerable clinical and genetic heterogeneity, with disruption of over 100 genes causing the variable involvement of several organs, including the central nervous system, kidneys, retina, skeleton and liver. Pathogenic variants in one and the same gene may associate with a wide range of ciliopathy phenotypes, supporting the hypothesis that the individual genetic background, with potential additional variants in other ciliary genes, may contribute to a mutational load eventually determining the phenotypic manifestations of each patient. Functional studies in animal models have uncovered some of the pathophysiological mechanisms linking ciliary gene mutations to the observed phenotypes; yet, the lack of reliable human cell models has previously limited preclinical research and the development of new therapeutic strategies for primary ciliopathies. Recent technical advances in the generation of patient-derived two-dimensional (2D) and three-dimensional (3D) cellular models give a new spur to this research, allowing the study of pathomechanisms while maintaining the complexity of the genetic background of each patient, and enabling the development of innovative treatments to target specific pathways. This review provides an overview of available models for primary ciliopathies, from existing in vivo models to more recent patient-derived 2D and 3D in vitro models. We highlight the advantages of each model in understanding the functional basis of primary ciliopathies and facilitating novel regenerative medicine, gene therapy and drug testing strategies for these disorders.
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9
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Li X, Liu N, Yang C, Zhang W, Lui S. Cerebellar gray matter volume changes in patients with schizophrenia: A voxel-based meta-analysis. Front Psychiatry 2022; 13:1083480. [PMID: 36620665 PMCID: PMC9814486 DOI: 10.3389/fpsyt.2022.1083480] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND In schizophrenia, the structural changes in the cerebellum are associated with patients' cognition and motor deficits. However, the findings are inconsistent owing to the heterogeneity in sample size, magnetic resonance imaging (MRI) scanners, and other factors among them. In this study, we conducted a meta-analysis to characterize the anatomical changes in cerebellar subfields in patients with schizophrenia. METHODS Systematic research was conducted to identify studies that compare the gray matter volume (GMV) differences in the cerebellum between patients with schizophrenia and healthy controls with a voxel-based morphometry (VBM) method. A coordinate-based meta-analysis was adopted based on seed-based d mapping (SDM) software. An exploratory meta-regression analysis was conducted to associate clinical and demographic features with cerebellar changes. RESULTS Of note, 25 studies comprising 996 patients with schizophrenia and 1,109 healthy controls were included in the present meta-analysis. In patients with schizophrenia, decreased GMVs were demonstrated in the left Crus II, right lobule VI, and right lobule VIII, while no increased GMV was identified. In the meta-regression analysis, the mean age and illness duration were negatively associated with the GMV in the left Crus II in patients with schizophrenia. CONCLUSION The most significant structural changes in the cerebellum are mainly located in the posterior cerebellar hemisphere in patients with schizophrenia. The decreased GMVs of these regions might partly explain the cognitive deficits and motor symptoms in patients with schizophrenia.
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Affiliation(s)
- Xing Li
- Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital of Sichuan University, Chengdu, China
| | - Naici Liu
- Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital of Sichuan University, Chengdu, China
| | - Chengmin Yang
- Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital of Sichuan University, Chengdu, China
| | - Wenjing Zhang
- Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital of Sichuan University, Chengdu, China
| | - Su Lui
- Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital of Sichuan University, Chengdu, China
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Suciu SK, Long AB, Caspary T. Smoothened and ARL13B are critical in mouse for superior cerebellar peduncle targeting. Genetics 2021; 218:6300527. [PMID: 34132778 PMCID: PMC8864748 DOI: 10.1093/genetics/iyab084] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/15/2021] [Indexed: 01/07/2023] Open
Abstract
Patients with the ciliopathy Joubert syndrome present with physical anomalies, intellectual disability, and a hindbrain malformation described as the "molar tooth sign" due to its appearance on an MRI. This radiological abnormality results from a combination of hypoplasia of the cerebellar vermis and inappropriate targeting of the white matter tracts of the superior cerebellar peduncles. ARL13B is a cilia-enriched regulatory GTPase established to regulate cell fate, cell proliferation, and axon guidance through vertebrate Hedgehog signaling. In patients, mutations in ARL13B cause Joubert syndrome. To understand the etiology of the molar tooth sign, we used mouse models to investigate the role of ARL13B during cerebellar development. We found that ARL13B regulates superior cerebellar peduncle targeting and these fiber tracts require Hedgehog signaling for proper guidance. However, in mouse, the Joubert-causing R79Q mutation in ARL13B does not disrupt Hedgehog signaling nor does it impact tract targeting. We found a small cerebellar vermis in mice lacking ARL13B function but no cerebellar vermis hypoplasia in mice expressing the Joubert-causing R79Q mutation. In addition, mice expressing a cilia-excluded variant of ARL13B that transduces Hedgehog normally showed normal tract targeting and vermis width. Taken together, our data indicate that ARL13B is critical for the control of cerebellar vermis width as well as superior cerebellar peduncle axon guidance, likely via Hedgehog signaling. Thus, our work highlights the complexity of ARL13B in molar tooth sign etiology.
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Affiliation(s)
- Sarah K Suciu
- Genetics and Molecular Biology Graduate Program, Emory University, Atlanta, GA 30322, USA,Department of Human Genetics, Emory University, Atlanta, GA 30322, USA
| | - Alyssa B Long
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA
| | - Tamara Caspary
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA,Corresponding author: Department of Human Genetics, 615 Michael Street, Suite 301, Atlanta, GA 30322.
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Lauri A, Fasano G, Venditti M, Dallapiccola B, Tartaglia M. In vivo Functional Genomics for Undiagnosed Patients: The Impact of Small GTPases Signaling Dysregulation at Pan-Embryo Developmental Scale. Front Cell Dev Biol 2021; 9:642235. [PMID: 34124035 PMCID: PMC8194860 DOI: 10.3389/fcell.2021.642235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/12/2021] [Indexed: 12/24/2022] Open
Abstract
While individually rare, disorders affecting development collectively represent a substantial clinical, psychological, and socioeconomic burden to patients, families, and society. Insights into the molecular mechanisms underlying these disorders are required to speed up diagnosis, improve counseling, and optimize management toward targeted therapies. Genome sequencing is now unveiling previously unexplored genetic variations in undiagnosed patients, which require functional validation and mechanistic understanding, particularly when dealing with novel nosologic entities. Functional perturbations of key regulators acting on signals' intersections of evolutionarily conserved pathways in these pathological conditions hinder the fine balance between various developmental inputs governing morphogenesis and homeostasis. However, the distinct mechanisms by which these hubs orchestrate pathways to ensure the developmental coordinates are poorly understood. Integrative functional genomics implementing quantitative in vivo models of embryogenesis with subcellular precision in whole organisms contribute to answering these questions. Here, we review the current knowledge on genes and mechanisms critically involved in developmental syndromes and pediatric cancers, revealed by genomic sequencing and in vivo models such as insects, worms and fish. We focus on the monomeric GTPases of the RAS superfamily and their influence on crucial developmental signals and processes. We next discuss the effectiveness of exponentially growing functional assays employing tractable models to identify regulatory crossroads. Unprecedented sophistications are now possible in zebrafish, i.e., genome editing with single-nucleotide precision, nanoimaging, highly resolved recording of multiple small molecules activity, and simultaneous monitoring of brain circuits and complex behavioral response. These assets permit accurate real-time reporting of dynamic small GTPases-controlled processes in entire organisms, owning the potential to tackle rare disease mechanisms.
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Affiliation(s)
- Antonella Lauri
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | | | | | | | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
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12
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Corkins ME, Krneta-Stankic V, Kloc M, Miller RK. Aquatic models of human ciliary diseases. Genesis 2021; 59:e23410. [PMID: 33496382 PMCID: PMC8593908 DOI: 10.1002/dvg.23410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 11/06/2022]
Abstract
Cilia are microtubule-based structures that either transmit information into the cell or move fluid outside of the cell. There are many human diseases that arise from malfunctioning cilia. Although mammalian models provide vital insights into the underlying pathology of these diseases, aquatic organisms such as Xenopus and zebrafish provide valuable tools to help screen and dissect out the underlying causes of these diseases. In this review we focus on recent studies that identify or describe different types of human ciliopathies and outline how aquatic organisms have aided our understanding of these diseases.
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Affiliation(s)
- Mark E. Corkins
- Department of Pediatrics, Pediatric Research Center, UTHealth McGovern Medical School, Houston Texas 77030
| | - Vanja Krneta-Stankic
- Department of Pediatrics, Pediatric Research Center, UTHealth McGovern Medical School, Houston Texas 77030
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Genes & Development, Houston Texas 77030
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Genetics & Epigenetics, Houston, Texas 77030
| | - Malgorzata Kloc
- Houston Methodist, Research Institute, Houston Texas 77030
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston Texas 77030
| | - Rachel K. Miller
- Department of Pediatrics, Pediatric Research Center, UTHealth McGovern Medical School, Houston Texas 77030
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Genetics & Epigenetics, Houston, Texas 77030
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston Texas 77030
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Biochemistry & Cell Biology, Houston Texas 77030
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