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Nishikawa M, Hayashi S, Nakayama A, Nishio Y, Shiraki A, Ito H, Maruyama K, Muramatsu Y, Ogi T, Mizuno S, Nagata KI. Pathophysiological significance of the p.E31G variant in RAC1 responsible for a neurodevelopmental disorder with microcephaly. Biochim Biophys Acta Mol Basis Dis 2024; 1871:167520. [PMID: 39307291 DOI: 10.1016/j.bbadis.2024.167520] [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: 05/29/2024] [Revised: 09/04/2024] [Accepted: 09/16/2024] [Indexed: 09/29/2024]
Abstract
RAC1 encodes a Rho family small GTPase that regulates actin cytoskeletal reorganization and intracellular signaling pathways. Pathogenic RAC1 variants lead to a neurodevelopmental disorder with diverse phenotypic manifestations, including abnormalities in brain size and facial dysmorphism. However, the underlying pathophysiological mechanisms have yet to be elucidated. Here, we present the case of a school-aged male who exhibited global developmental delay, intellectual disability, and acquired microcephaly. Through whole exome sequencing, we identified a novel de novo variant in RAC1, (NM_006908.5): c.92 A > G,p.(E31G). We then examined the pathophysiological significance of the p.E31G variant by focusing on brain development. Biochemical analyses revealed that the recombinant RAC1-E31G had no discernible impact on the intrinsic GDP/GTP exchange activity. However, it exhibited a slight inhibitory effect on GTP hydrolysis. Conversely, it demonstrated a typical response to both a guanine-nucleotide exchange factor and a GTPase-activating protein. In transient expression analyses using COS7 cells, RAC1-E31G exhibited minimal interaction with the downstream effector PAK1, even in its GTP-bound state. Additionally, overexpression of RAC1-E31G was observed to exert a weak inhibitory effect on the differentiation of primary cultured hippocampal neurons. Moreover, in vivo studies employing in utero electroporation revealed that acute expression of RAC1-E31G resulted in impairments in axonal elongation and dendritic arborization in the young adult stage. These findings suggest that the p.E31G variant functions as a dominant-negative version in the PAK1-mediated signaling pathway and is responsible for the clinical features observed in the patient under investigation, namely microcephaly and intellectual disability.
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Affiliation(s)
- Masashi Nishikawa
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan
| | - Shin Hayashi
- Department of Genetics, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan
| | - Atsushi Nakayama
- Department of Pediatrics, Japanese Red Cross Aichi Medical Center Nagoya Daiichi Hospital, 3-35 Michishita-cho, Nagoya 453-8511, Japan
| | - Yosuke Nishio
- Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Furo-Cho, Nagoya 464-8602, Japan
| | - Anna Shiraki
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Nagoya 466-8550, Japan
| | - Hidenori Ito
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan
| | - Kouichi Maruyama
- Central Hospital, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan
| | - Yukako Muramatsu
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Nagoya 466-8550, Japan
| | - Tomoo Ogi
- Department of Genetics, Research Institute of Environmental Medicine, Nagoya University, Furo-Cho, Nagoya 464-8602, Japan
| | - Seiji Mizuno
- Central Hospital, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan
| | - Koh-Ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan; Department of Neurochemistry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Nagoya 466-8550, Japan.
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2
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Song L, Xu Q, Chen R, Sun W, Zhan J. KLF1 Activates RAC3 to Mediate Fatty Acid Synthesis and Enhance Cisplatin Resistance in Bladder Cancer Cells. Am J Mens Health 2024; 18:15579883241273305. [PMID: 39376007 PMCID: PMC11459471 DOI: 10.1177/15579883241273305] [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: 06/26/2024] [Revised: 09/10/2024] [Accepted: 07/05/2024] [Indexed: 10/09/2024] Open
Abstract
While cisplatin remains a frontline treatment for bladder cancer (BCa), the onset of resistance greatly hampers its effectiveness. RAC3 is closely linked to chemoresistance in cancer cells, but its specific role in cisplatin resistance within BCa is still elusive. RAC3 expression in BCa was analyzed using bioinformatics and quantitative polymerase chain reaction (qPCR). The gene set enrichment analysis (GSEA) identified RAC3-enriched pathways and the correlation between RAC3 and fatty acid synthase (FASN), a gene involved in fatty acid synthesis. Potential upstream transcription factors of RAC3 were predicted and their interaction with RAC3 was confirmed via dual-luciferase and chromatin immunoprecipitation (ChIP) assays. T24/DDP, a cisplatin-resistant BCa cell line, was established to probe into the regulatory role of RAC3 in cisplatin resistance. Cell proliferation was evaluated by colony formation and the IC50 values after cisplatin treatment were determined using cell counting kit-8 (CCK-8). The levels of free fatty acids and triglycerides (TGs), as well as the expression of DGAT2 and FASN proteins, were measured to gauge the extent of fatty acid synthesis in cells. Elevated expression of RAC3 was observed in BCa and the cisplatin-resistant BCa cells (T24/DDP). The knockdown of RAC3 within T24/DDP cells was demonstrated to counteract cisplatin resistance. Subsequent analyses identified RAC3 as being notably enriched in the fatty acid synthesis pathway, with Kruppel-like factor 1 (KLF1) emerging as a key upstream regulator. The overexpression of RAC3 was correlated with increased cisplatin resistance in T24/DDP cells, an effect that was mitigated by the addition of the FASN inhibitor, Orlistat. Furthermore, the downregulation of KLF1 suppressed RAC3 expression, disrupted fatty acid synthesis, and attenuated cisplatin resistance in T24/DDP cells. Conversely, the co-overexpression of RAC3 counteracted the effects conferred by KLF1 knockdown. Our study has validated that KLF1 activates RAC3 to mediate fatty acid synthesis and promote cisplatin resistance in BCa, suggesting the KLF1/RAC3 axis as a potential target for combating cisplatin-resistant BCa.
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Affiliation(s)
- Lide Song
- Department of Urology, Zhuji People’s Hospital, Zhuji, China
| | - Qi Xu
- Department of Urology, Zhuji People’s Hospital, Zhuji, China
| | - Rong Chen
- Department of Urology, Zhuji People’s Hospital, Zhuji, China
| | - Wanghong Sun
- Department of Urology, Zhuji People’s Hospital, Zhuji, China
| | - Jianfei Zhan
- Department of Urology, Zhuji People’s Hospital, Zhuji, China
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3
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Song Q, Geng H, Zhen H, Liu H, Deng H, Yuan Z, Zhang J, Cao Z, Pang Q, Zhao B. DjFARP Contributes to the Regeneration and Maintenance of the Brain through Activation of DjRac1 in Dugesia japonica. Mol Neurobiol 2023; 60:6294-6306. [PMID: 37442859 DOI: 10.1007/s12035-023-03478-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 07/02/2023] [Indexed: 07/15/2023]
Abstract
FERM, RhoGEF, and Pleckstrin domain protein (FARP) mediated RhoGTPase pathways are involved in diverse biological processes, such as neuronal development and tumorigenesis. However, little is known about their role in neural regeneration. We uncovered for the first time that FARP-Rac1 signaling plays an important role in neural regeneration in Dugesia japonica, a planarian that possesses unparalleled regenerative capacities. The planarian FARP homolog DjFARP was primarily expressed in both intact and regenerating brain and pharynx tissue. Functional studies suggested that downregulation of DjFARP with dsRNA in Dugesia japonica led to smaller brain sizes, defects in brain lateral branches, and loss of cholinergic, GABAergic, and dopaminergic neurons in both intact and regenerating animals. Moreover, the Rho GTPase DjRac1 was shown to play a similar role in neural regeneration and maintenance. Rac1 activation assay showed that DjFARP acts as a guanine nucleotide exchange factor (GEF) for DjRac1. Together, these findings indicate that the brain defects seen in DjFARP knockdown animals may be attributable to DjRac1 inactivation. In conclusion, our study demonstrated that DjFARP-DjRac1 signaling was required for the maintenance and proper regeneration of the brain in Dugesia japonica.
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Affiliation(s)
- Qian Song
- Laboratory of Developmental and Evolutionary Biology, Shandong University of Technology, 266 Xincun West Road, Zibo, 255049, People's Republic of China
| | - Huazhi Geng
- School of Life Sciences and Medicine, Shandong University of Technology, Zibo, 255049, China
| | - Hui Zhen
- Laboratory of Developmental and Evolutionary Biology, Shandong University of Technology, 266 Xincun West Road, Zibo, 255049, People's Republic of China
| | - Hongjin Liu
- Zibo Maternal and Child Health Hospital, Zibo, 255000, China
| | - Hongkuan Deng
- Zibo Maternal and Child Health Hospital, Zibo, 255000, China
| | - Zuoqing Yuan
- Zibo Maternal and Child Health Hospital, Zibo, 255000, China
| | - Jianyong Zhang
- Zibo Maternal and Child Health Hospital, Zibo, 255000, China
| | - Zhonghong Cao
- Zibo Maternal and Child Health Hospital, Zibo, 255000, China
| | - Qiuxiang Pang
- Zibo Maternal and Child Health Hospital, Zibo, 255000, China
| | - Bosheng Zhao
- Laboratory of Developmental and Evolutionary Biology, Shandong University of Technology, 266 Xincun West Road, Zibo, 255049, People's Republic of China.
- Zibo Maternal and Child Health Hospital, Zibo, 255000, China.
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4
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Ali NH, Al-Kuraishy HM, Al-Gareeb AI, Alnaaim SA, Alexiou A, Papadakis M, Saad HM, Batiha GES. Autophagy and autophagy signaling in Epilepsy: possible role of autophagy activator. Mol Med 2023; 29:142. [PMID: 37880579 PMCID: PMC10598971 DOI: 10.1186/s10020-023-00742-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/16/2023] [Indexed: 10/27/2023] Open
Abstract
Autophagy is an explicit cellular process to deliver dissimilar cytoplasmic misfolded proteins, lipids and damaged organelles to the lysosomes for degradation and elimination. The mechanistic target of rapamycin (mTOR) is the main negative regulator of autophagy. The mTOR pathway is involved in regulating neurogenesis, synaptic plasticity, neuronal development and excitability. Exaggerated mTOR activity is associated with the development of temporal lobe epilepsy, genetic and acquired epilepsy, and experimental epilepsy. In particular, mTOR complex 1 (mTORC1) is mainly involved in epileptogenesis. The investigation of autophagy's involvement in epilepsy has recently been conducted, focusing on the critical role of rapamycin, an autophagy inducer, in reducing the severity of induced seizures in animal model studies. The induction of autophagy could be an innovative therapeutic strategy in managing epilepsy. Despite the protective role of autophagy against epileptogenesis and epilepsy, its role in status epilepticus (SE) is perplexing and might be beneficial or detrimental. Therefore, the present review aims to revise the possible role of autophagy in epilepsy.
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Affiliation(s)
- Naif H Ali
- Department of Internal Medicine, Medical College, Najran university, Najran, Saudi Arabia
| | - Hayder M Al-Kuraishy
- Department of Clinical Pharmacology and Medicine, College of Medicine, ALmustansiriyia University, P.O. Box 14132, Baghdad, Iraq
| | - Ali I Al-Gareeb
- Department of Clinical Pharmacology and Medicine, College of Medicine, ALmustansiriyia University, P.O. Box 14132, Baghdad, Iraq
| | - Saud A Alnaaim
- Clinical Neurosciences Department, College of Medicine, King Faisal University, Hofuf, Saudi Arabia
| | - Athanasios Alexiou
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham, NSW, 2770, Australia
- AFNP Med, Wien, 1030, Austria
| | - Marios Papadakis
- Department of Surgery II, University Hospital Witten-Herdecke, University of Witten-Herdecke, Heusnerstrasse 40, 42283, Wuppertal, Germany.
| | - Hebatallah M Saad
- Department of Pathology, Faculty of Veterinary Medicine, Matrouh University, Matrouh, Matrouh, 51744, Egypt.
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, AlBeheira, 22511, Egypt.
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5
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Toudji I, Toumi A, Chamberland É, Rossignol E. Interneuron odyssey: molecular mechanisms of tangential migration. Front Neural Circuits 2023; 17:1256455. [PMID: 37779671 PMCID: PMC10538647 DOI: 10.3389/fncir.2023.1256455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/21/2023] [Indexed: 10/03/2023] Open
Abstract
Cortical GABAergic interneurons are critical components of neural networks. They provide local and long-range inhibition and help coordinate network activities involved in various brain functions, including signal processing, learning, memory and adaptative responses. Disruption of cortical GABAergic interneuron migration thus induces profound deficits in neural network organization and function, and results in a variety of neurodevelopmental and neuropsychiatric disorders including epilepsy, intellectual disability, autism spectrum disorders and schizophrenia. It is thus of paramount importance to elucidate the specific mechanisms that govern the migration of interneurons to clarify some of the underlying disease mechanisms. GABAergic interneurons destined to populate the cortex arise from multipotent ventral progenitor cells located in the ganglionic eminences and pre-optic area. Post-mitotic interneurons exit their place of origin in the ventral forebrain and migrate dorsally using defined migratory streams to reach the cortical plate, which they enter through radial migration before dispersing to settle in their final laminar allocation. While migrating, cortical interneurons constantly change their morphology through the dynamic remodeling of actomyosin and microtubule cytoskeleton as they detect and integrate extracellular guidance cues generated by neuronal and non-neuronal sources distributed along their migratory routes. These processes ensure proper distribution of GABAergic interneurons across cortical areas and lamina, supporting the development of adequate network connectivity and brain function. This short review summarizes current knowledge on the cellular and molecular mechanisms controlling cortical GABAergic interneuron migration, with a focus on tangential migration, and addresses potential avenues for cell-based interneuron progenitor transplants in the treatment of neurodevelopmental disorders and epilepsy.
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Affiliation(s)
- Ikram Toudji
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Asmaa Toumi
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, Canada
| | - Émile Chamberland
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Elsa Rossignol
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
- Department of Pediatrics, Université de Montréal, Montréal, QC, Canada
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6
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Kounoupa Z, Tivodar S, Theodorakis K, Kyriakis D, Denaxa M, Karagogeos D. Rac1 and Rac3 GTPases and TPC2 are required for axonal outgrowth and migration of cortical interneurons. J Cell Sci 2023; 136:286920. [PMID: 36744839 DOI: 10.1242/jcs.260373] [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: 06/24/2022] [Accepted: 01/31/2023] [Indexed: 02/07/2023] Open
Abstract
Rho GTPases, among them Rac1 and Rac3, are major transducers of extracellular signals and are involved in multiple cellular processes. In cortical interneurons, the neurons that control the balance between excitation and inhibition of cortical circuits, Rac1 and Rac3 are essential for their development. Ablation of both leads to a severe reduction in the numbers of mature interneurons found in the murine cortex, which is partially due to abnormal cell cycle progression of interneuron precursors and defective formation of growth cones in young neurons. Here, we present new evidence that upon Rac1 and Rac3 ablation, centrosome, Golgi complex and lysosome positioning is significantly perturbed, thus affecting both interneuron migration and axon growth. Moreover, for the first time, we provide evidence of altered expression and localization of the two-pore channel 2 (TPC2) voltage-gated ion channel that mediates Ca2+ release. Pharmacological inhibition of TPC2 negatively affected axonal growth and migration of interneurons. Our data, taken together, suggest that TPC2 contributes to the severe phenotype in axon growth initiation, extension and interneuron migration in the absence of Rac1 and Rac3.
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Affiliation(s)
- Zouzana Kounoupa
- Institute of Molecular Biology and Biotechnology (IMBB, FORTH), Heraklion 71110, Greece.,Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion 71110, Greece
| | - Simona Tivodar
- Institute of Molecular Biology and Biotechnology (IMBB, FORTH), Heraklion 71110, Greece.,Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion 71110, Greece
| | - Kostas Theodorakis
- Institute of Molecular Biology and Biotechnology (IMBB, FORTH), Heraklion 71110, Greece.,Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion 71110, Greece
| | - Dimitrios Kyriakis
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, L-4365 Esch-sur-Alzette, Luxembourg
| | - Myrto Denaxa
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Centre 'Al. Fleming', Vari, 16672, Greece
| | - Domna Karagogeos
- Institute of Molecular Biology and Biotechnology (IMBB, FORTH), Heraklion 71110, Greece.,Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion 71110, Greece
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7
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Nishikawa M, Scala M, Umair M, Ito H, Waqas A, Striano P, Zara F, Costain G, Capra V, Nagata KI. Gain-of-function p.F28S variant in RAC3 disrupts neuronal differentiation, migration and axonogenesis during cortical development, leading to neurodevelopmental disorder. J Med Genet 2023; 60:223-232. [PMID: 35595279 DOI: 10.1136/jmedgenet-2022-108483] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 05/02/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND RAC3 encodes a Rho family small GTPase that regulates the behaviour and organisation of actin cytoskeleton and intracellular signal transduction. Variants in RAC3 can cause a phenotypically heterogeneous neurodevelopmental disorder with structural brain anomalies and dysmorphic facies. The pathomechanism of this recently discovered genetic disorder remains unclear. METHODS We investigated an early adolescent female with intellectual disability, drug-responsive epilepsy and white matter abnormalities. Through exome sequencing, we identified the novel de novo variant (NM_005052.3): c.83T>C (p.Phe28Ser) in RAC3. We then examined the pathophysiological significance of the p.F28S variant in comparison with the recently reported disease-causing p.Q61L variant, which results in a constitutively activated version of RAC3. RESULTS In vitro analyses revealed that the p.F28S variant was spontaneously activated by substantially increased intrinsic GTP/GDP-exchange activity and bound to downstream effectors tested, such as PAK1 and MLK2. The variant suppressed the differentiation of primary cultured hippocampal neurons and caused cell rounding with lamellipodia. In vivo analyses using in utero electroporation showed that acute expression of the p.F28S variant caused migration defects of excitatory neurons and axon growth delay during corticogenesis. Notably, defective migration was rescued by a dominant negative version of PAK1 but not MLK2. CONCLUSION Our results indicate that RAC3 is critical for brain development and the p.F28S variant causes morphological and functional defects in cortical neurons, likely due to the hyperactivation of PAK1.
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Affiliation(s)
- Masashi Nishikawa
- Department of Molecular Neurobiology, Aichi Developmental Disability Center, Kasugai, Japan
| | - Marcello Scala
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy .,Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Muhammad Umair
- Medical Genomics Research Department, King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia.,Department of Life Sciences, School of Science, University of Management and Technology, Lahore, Pakistan
| | - Hidenori Ito
- Department of Molecular Neurobiology, Aichi Developmental Disability Center, Kasugai, Japan
| | - Ahmed Waqas
- Department Zoology, Division of Science and Technology, University of Education, Lahore, Pakistan
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.,Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Federico Zara
- Unit of Medical Genetics, IRCCS Giannina Gaslini Institute, Genova, Italy
| | - Gregory Costain
- Genetics and Genome Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Valeria Capra
- Unit of Medical Genetics, IRCCS Giannina Gaslini Institute, Genova, Italy
| | - Koh-Ichi Nagata
- Department of Molecular Neurobiology, Aichi Developmental Disability Center, Kasugai, Japan .,Department of Neurochemistry, Nagoya University Graduate School of Medicine, Nagoya, Japan
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8
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Rac is required for the survival of cortical neurons. Exp Neurol 2023; 361:114316. [PMID: 36586552 DOI: 10.1016/j.expneurol.2022.114316] [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: 09/23/2022] [Revised: 12/07/2022] [Accepted: 12/27/2022] [Indexed: 12/29/2022]
Abstract
Rac1, a member of small Rho GTPases, is involved in diverse cellular processes in neuronal cells. Rac1 plays especially important roles during development, and its roles have been extensively studied using Rac1-deficient mice. Rac3, a close homolog of Rac1, is ubiquitously expressed in the nervous system and may therefore compensate for Rac1 in Rac1-deficient cells. Exploration of the roles of Rac in neurons may therefore be difficult. We thus deleted both Rac1 and Rac3 in cortical neurons. Rac-deficient cerebral cortices formed slightly hypoplastic but almost normally layered structures at birth, but cortical neurons underwent apoptosis soon after birth. Rac-deficient cortical neurons had poor survivability and there was reduction in the length and the number of neurites in vitro. Activation of Pak1, a downstream effector of Rac, in Rac-deficient cortical neurons rescued the survivability in vitro. Pak1-activated Rac-deficient neurons had numerous dendrites, but no axons. Restoration of p35, a regulator of Cdk5, partly rescued the survivability of Rac-deficient neurons both in vitro and in vivo. Expression of p35 also partly rescued the length and the number of neurites in Rac-deficient neurons in vitro. Rac was shown to be indispensable for the survival of cortical neurons, and Pak1 and Cdk5/p35 work as downstream effectors of Rac to promote neuronal survival.
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9
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Liaci C, Camera M, Zamboni V, Sarò G, Ammoni A, Parmigiani E, Ponzoni L, Hidisoglu E, Chiantia G, Marcantoni A, Giustetto M, Tomagra G, Carabelli V, Torelli F, Sala M, Yanagawa Y, Obata K, Hirsch E, Merlo GR. Loss of ARHGAP15 affects the directional control of migrating interneurons in the embryonic cortex and increases susceptibility to epilepsy. Front Cell Dev Biol 2022; 10:875468. [PMID: 36568982 PMCID: PMC9774038 DOI: 10.3389/fcell.2022.875468] [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: 02/14/2022] [Accepted: 11/07/2022] [Indexed: 12/13/2022] Open
Abstract
GTPases of the Rho family are components of signaling pathways linking extracellular signals to the control of cytoskeleton dynamics. Among these, RAC1 plays key roles during brain development, ranging from neuronal migration to neuritogenesis, synaptogenesis, and plasticity. RAC1 activity is positively and negatively controlled by guanine nucleotide exchange factors (GEFs), guanosine nucleotide dissociation inhibitors (GDIs), and GTPase-activating proteins (GAPs), but the specific role of each regulator in vivo is poorly known. ARHGAP15 is a RAC1-specific GAP expressed during development in a fraction of migrating cortical interneurons (CINs) and in the majority of adult CINs. During development, loss of ARHGAP15 causes altered directionality of the leading process of tangentially migrating CINs, along with altered morphology in vitro. Likewise, time-lapse imaging of embryonic CINs revealed a poorly coordinated directional control during radial migration, possibly due to a hyper-exploratory behavior. In the adult cortex, the observed defects lead to subtle alteration in the distribution of CALB2-, SST-, and VIP-positive interneurons. Adult Arhgap15-knock-out mice also show reduced CINs intrinsic excitability, spontaneous subclinical seizures, and increased susceptibility to the pro-epileptic drug pilocarpine. These results indicate that ARHGAP15 imposes a fine negative regulation on RAC1 that is required for morphological maturation and directional control during CIN migration, with consequences on their laminar distribution and inhibitory function.
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Affiliation(s)
- Carla Liaci
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Mattia Camera
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Valentina Zamboni
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Gabriella Sarò
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Alessandra Ammoni
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | | | - Luisa Ponzoni
- Neuroscience Institute, Consiglio Nazionale Ricerche, Milan, Italy
| | - Enis Hidisoglu
- Department of Drug Science, NIS Center, University of Turin, Turin, Italy
| | - Giuseppe Chiantia
- Department of Neuroscience and National Institute of Neuroscience, University of Turin, Turin, Italy
| | - Andrea Marcantoni
- Department of Drug Science, NIS Center, University of Turin, Turin, Italy
| | - Maurizio Giustetto
- Department of Neuroscience and National Institute of Neuroscience, University of Turin, Turin, Italy
| | - Giulia Tomagra
- Department of Drug Science, NIS Center, University of Turin, Turin, Italy
| | | | - Federico Torelli
- Institute for Physiology I, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg, Germany,Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Mariaelvina Sala
- Neuroscience Institute, Consiglio Nazionale Ricerche, Milan, Italy
| | - Yuchio Yanagawa
- Department of Genetic Behavioral Neuroscience, Gunma University, Maebashi, Japan
| | | | - Emilio Hirsch
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy
| | - Giorgio R. Merlo
- Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin, Italy,*Correspondence: Giorgio R. Merlo,
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10
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Donta MS, Srivastava Y, McCrea PD. Delta-Catenin as a Modulator of Rho GTPases in Neurons. Front Cell Neurosci 2022; 16:939143. [PMID: 35860313 PMCID: PMC9289679 DOI: 10.3389/fncel.2022.939143] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 06/09/2022] [Indexed: 12/03/2022] Open
Abstract
Small Rho GTPases are molecular switches that are involved in multiple processes including regulation of the actin cytoskeleton. These GTPases are activated (turned on) and inactivated (turned off) through various upstream effector molecules to carry out many cellular functions. One such upstream modulator of small Rho GTPase activity is delta-catenin, which is a protein in the p120-catenin subfamily that is enriched in the central nervous system. Delta-catenin affects small GTPase activity to assist in the developmental formation of dendrites and dendritic spines and to maintain them once they mature. As the dendritic arbor and spine density are crucial for synapse formation and plasticity, delta-catenin's ability to modulate small Rho GTPases is necessary for proper learning and memory. Accordingly, the misregulation of delta-catenin and small Rho GTPases has been implicated in several neurological and non-neurological pathologies. While links between delta-catenin and small Rho GTPases have yet to be studied in many contexts, known associations include some cancers, Alzheimer's disease (AD), Cri-du-chat syndrome, and autism spectrum disorder (ASD). Drawing from established studies and recent discoveries, this review explores how delta-catenin modulates small Rho GTPase activity. Future studies will likely elucidate how PDZ proteins that bind delta-catenin further influence small Rho GTPases, how delta-catenin may affect small GTPase activity at adherens junctions when bound to N-cadherin, mechanisms behind delta-catenin's ability to modulate Rac1 and Cdc42, and delta-catenin's ability to modulate small Rho GTPases in the context of diseases, such as cancer and AD.
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Affiliation(s)
- Maxsam S. Donta
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
- Program in Genetics and Epigenetics, The University of Texas MD Anderson Cancer Center University of Texas Health Science Center Houston Graduate School of Biomedical Science, Houston, TX, United States
| | - Yogesh Srivastava
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Pierre D. McCrea
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
- Program in Genetics and Epigenetics, The University of Texas MD Anderson Cancer Center University of Texas Health Science Center Houston Graduate School of Biomedical Science, Houston, TX, United States
- Program in Neuroscience, The University of Texas MD Anderson Cancer Center University of Texas Health Science Center Houston Graduate School of Biomedical Science, Houston, TX, United States
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11
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Scala M, Nishikawa M, Ito H, Tabata H, Khan T, Accogli A, Davids L, Ruiz A, Chiurazzi P, Cericola G, Schulte B, Monaghan KG, Begtrup A, Torella A, Pinelli M, Denommé-Pichon AS, Vitobello A, Racine C, Mancardi MM, Kiss C, Guerin A, Wu W, Gabau Vila E, Mak BC, Martinez-Agosto JA, Gorin MB, Duz B, Bayram Y, Carvalho CMB, Vengoechea JE, Chitayat D, Tan TY, Callewaert B, Kruse B, Bird LM, Faivre L, Zollino M, Biskup S, Striano P, Nigro V, Severino M, Capra V, Costain G, Nagata KI. Variant-specific changes in RAC3 function disrupt corticogenesis in neurodevelopmental phenotypes. Brain 2022; 145:3308-3327. [PMID: 35851598 PMCID: PMC9473360 DOI: 10.1093/brain/awac106] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 02/01/2022] [Accepted: 03/13/2022] [Indexed: 01/17/2023] Open
Abstract
Variants in RAC3, encoding a small GTPase RAC3 which is critical for the regulation of actin cytoskeleton and intracellular signal transduction, are associated with a rare neurodevelopmental disorder with structural brain anomalies and facial dysmorphism. We investigated a cohort of 10 unrelated participants presenting with global psychomotor delay, hypotonia, behavioural disturbances, stereotyped movements, dysmorphic features, seizures and musculoskeletal abnormalities. MRI of brain revealed a complex pattern of variable brain malformations, including callosal abnormalities, white matter thinning, grey matter heterotopia, polymicrogyria/dysgyria, brainstem anomalies and cerebellar dysplasia. These patients harboured eight distinct de novo RAC3 variants, including six novel variants (NM_005052.3): c.34G > C p.G12R, c.179G > A p.G60D, c.186_188delGGA p.E62del, c.187G > A p.D63N, c.191A > G p.Y64C and c.348G > C p.K116N. We then examined the pathophysiological significance of these novel and previously reported pathogenic variants p.P29L, p.P34R, p.A59G, p.Q61L and p.E62K. In vitro analyses revealed that all tested RAC3 variants were biochemically and biologically active to variable extent, and exhibited a spectrum of different affinities to downstream effectors including p21-activated kinase 1. We then focused on the four variants p.Q61L, p.E62del, p.D63N and p.Y64C in the Switch II region, which is essential for the biochemical activity of small GTPases and also a variation hot spot common to other Rho family genes, RAC1 and CDC42. Acute expression of the four variants in embryonic mouse brain using in utero electroporation caused defects in cortical neuron morphology and migration ending up with cluster formation during corticogenesis. Notably, defective migration by p.E62del, p.D63N and p.Y64C were rescued by a dominant negative version of p21-activated kinase 1. Our results indicate that RAC3 variants result in morphological and functional defects in cortical neurons during brain development through variant-specific mechanisms, eventually leading to heterogeneous neurodevelopmental phenotypes.
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Affiliation(s)
| | | | | | - Hidenori Tabata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan
| | - Tayyaba Khan
- Genetics and Genome Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Andrea Accogli
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Laura Davids
- Department of Human Genetics, Emory Healthcare, Atlanta, GA 30322, USA
| | - Anna Ruiz
- Genetics Laboratory, UDIAT-Centre Diagnòstic, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí I3PT, Universitat Autònoma de, Barcelona, Sabadell, Spain
| | - Pietro Chiurazzi
- Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Sezione di Medicina Genomica, Università Cattolica Sacro Cuore, Rome, Italy,Genetica Medica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Gabriella Cericola
- Neuropediatric Department, Helios-Klinikum Hildesheim, Hildesheim, Germany
| | | | | | | | - Annalaura Torella
- Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy,Department of Precision Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Michele Pinelli
- Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy
| | - Anne Sophie Denommé-Pichon
- INSERM UMR1231 Génétique des Anomalies du Développement, Université de Bourgogne Franche-Comté, Dijon, France,Laboratoire de Génétique Moléculaire, UF Innovation en diagnostic génomique des maladies rares, Plateau Technique de Biologie, CHU de Dijon Bourgogne, Dijon, France,Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'interrégion Est, FHU TRANSLAD, Hôpital d'Enfants, CHU de Dijon Bourgogne, Dijon, France
| | - Antonio Vitobello
- INSERM UMR1231 Génétique des Anomalies du Développement, Université de Bourgogne Franche-Comté, Dijon, France,Laboratoire de Génétique Moléculaire, UF Innovation en diagnostic génomique des maladies rares, Plateau Technique de Biologie, CHU de Dijon Bourgogne, Dijon, France
| | - Caroline Racine
- Laboratoire de Génétique Moléculaire, UF Innovation en diagnostic génomique des maladies rares, Plateau Technique de Biologie, CHU de Dijon Bourgogne, Dijon, France,Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'interrégion Est, FHU TRANSLAD, Hôpital d'Enfants, CHU de Dijon Bourgogne, Dijon, France
| | - Maria Margherita Mancardi
- Unit of Child Neuropsychiatry, Department of Medical and Surgical Neuroscience and Rehabilitation, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Courtney Kiss
- Division of Medical Genetics, Department of Pediatrics, Queen’s University, Kingston, ON K7L 2V7, Canada
| | - Andrea Guerin
- Division of Medical Genetics, Department of Pediatrics, Queen’s University, Kingston, ON K7L 2V7, Canada
| | - Wendy Wu
- Genetics and Genome Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada,Queen’s University, Kingston, ON, Canada
| | - Elisabeth Gabau Vila
- Paediatric Unit, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí I3PT, Universitat Autònoma de, Barcelona, Sabadell, Spain
| | - Bryan C Mak
- Department of Human Genetics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA
| | - Julian A Martinez-Agosto
- Department of Human Genetics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA,Department of Pediatrics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA,Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA
| | - Michael B Gorin
- Department of Human Genetics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA,Department of Ophthalmology, Jules Stein Eye Institute, David Geffen School of Medicine, UCLA, Los Angeles 90095, CA, USA,Brain Research Institute, UCLA, Los Angeles 90095, CA, USA
| | - Bugrahan Duz
- Haseki Training and Research Hospital, Istanbul, Turkey
| | - Yavuz Bayram
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA,Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Claudia M B Carvalho
- Pacific Northwest Research Institute, Seattle, WA 98122, USA,Baylor College of Medicine, Houston, TX 77030, USA
| | | | - David Chitayat
- The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada,Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Tiong Yang Tan
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, and Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Bert Callewaert
- Center for Medical Genetics, Ghent University Hospital, Gent, Belgium
| | - Bernd Kruse
- Neuropediatric Department, Helios-Klinikum Hildesheim, Hildesheim, Germany
| | - Lynne M Bird
- Department of Pediatrics, University of California San Diego, San Diego, CA, USA,Genetics/Dysmorphology, Rady Children’s Hospital San Diego, San Diego, CA, USA
| | - Laurence Faivre
- INSERM UMR1231 Génétique des Anomalies du Développement, Université de Bourgogne Franche-Comté, Dijon, France,Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'interrégion Est, FHU TRANSLAD, Hôpital d'Enfants, CHU de Dijon Bourgogne, Dijon, France
| | - Marcella Zollino
- Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Sezione di Medicina Genomica, Università Cattolica Sacro Cuore, Rome, Italy,Genetica Medica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Saskia Biskup
- Praxis für Humangenetik, Tübingen, Germany,CeGaT GmbH, Tübingen, Germany
| | | | | | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy,Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Vincenzo Nigro
- Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy,Department of Precision Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | | | - Valeria Capra
- Correspondence may also be addressed to: Valeria Capra Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy E-mail:
| | - Gregory Costain
- Correspondence may also be addressed to: Gregory Costain Division of Clinical and Metabolic Genetics Department of Pediatrics The Hospital for Sick Children Toronto, Ontario, Canada E-mail:
| | - Koh ichi Nagata
- Correspondence to: Koh-ichi Nagata Department of Molecular Neurobiology Institute for Developmental Research Aichi Human Service Center, 713-8 Kamiya Kasugai, Aichi 480-0392, Japan E-mail:
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12
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Duman JG, Blanco FA, Cronkite CA, Ru Q, Erikson KC, Mulherkar S, Saifullah AB, Firozi K, Tolias KF. Rac-maninoff and Rho-vel: The symphony of Rho-GTPase signaling at excitatory synapses. Small GTPases 2022; 13:14-47. [PMID: 33955328 PMCID: PMC9707551 DOI: 10.1080/21541248.2021.1885264] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 01/15/2023] Open
Abstract
Synaptic connections between neurons are essential for every facet of human cognition and are thus regulated with extreme precision. Rho-family GTPases, molecular switches that cycle between an active GTP-bound state and an inactive GDP-bound state, comprise a critical feature of synaptic regulation. Rho-GTPases are exquisitely controlled by an extensive suite of activators (GEFs) and inhibitors (GAPs and GDIs) and interact with many different signalling pathways to fulfill their roles in orchestrating the development, maintenance, and plasticity of excitatory synapses of the central nervous system. Among the mechanisms that control Rho-GTPase activity and signalling are cell surface receptors, GEF/GAP complexes that tightly regulate single Rho-GTPase dynamics, GEF/GAP and GEF/GEF functional complexes that coordinate multiple Rho-family GTPase activities, effector positive feedback loops, and mutual antagonism of opposing Rho-GTPase pathways. These complex regulatory mechanisms are employed by the cells of the nervous system in almost every step of development, and prominently figure into the processes of synaptic plasticity that underlie learning and memory. Finally, misregulation of Rho-GTPases plays critical roles in responses to neuronal injury, such as traumatic brain injury and neuropathic pain, and in neurodevelopmental and neurodegenerative disorders, including intellectual disability, autism spectrum disorder, schizophrenia, and Alzheimer's Disease. Thus, decoding the mechanisms of Rho-GTPase regulation and function at excitatory synapses has great potential for combatting many of the biggest current challenges in mental health.
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Affiliation(s)
- Joseph G. Duman
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Francisco A. Blanco
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Integrative Molecular and Biomedical Science Graduate Program, Baylor College of Medicine, Houston, TX, USA
| | - Christopher A. Cronkite
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
| | - Qin Ru
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kelly C. Erikson
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Ali Bin Saifullah
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Karen Firozi
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kimberley F. Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
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13
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Scala M, Nishikawa M, Nagata KI, Striano P. Pathophysiological Mechanisms in Neurodevelopmental Disorders Caused by Rac GTPases Dysregulation: What's behind Neuro-RACopathies. Cells 2021; 10:3395. [PMID: 34943902 PMCID: PMC8699292 DOI: 10.3390/cells10123395] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/23/2021] [Accepted: 11/30/2021] [Indexed: 02/07/2023] Open
Abstract
Rho family guanosine triphosphatases (GTPases) regulate cellular signaling and cytoskeletal dynamics, playing a pivotal role in cell adhesion, migration, and cell cycle progression. The Rac subfamily of Rho GTPases consists of three highly homologous proteins, Rac 1-3. The proper function of Rac1 and Rac3, and their correct interaction with guanine nucleotide-exchange factors (GEFs) and GTPase-activating proteins (GAPs) are crucial for neural development. Pathogenic variants affecting these delicate biological processes are implicated in different medical conditions in humans, primarily neurodevelopmental disorders (NDDs). In addition to a direct deleterious effect produced by genetic variants in the RAC genes, a dysregulated GTPase activity resulting from an abnormal function of GEFs and GAPs has been involved in the pathogenesis of distinctive emerging conditions. In this study, we reviewed the current pertinent literature on Rac-related disorders with a primary neurological involvement, providing an overview of the current knowledge on the pathophysiological mechanisms involved in the neuro-RACopathies.
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Affiliation(s)
- Marcello Scala
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16132 Genoa, Italy;
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Masashi Nishikawa
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan; (M.N.); (K.-i.N.)
| | - Koh-ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan; (M.N.); (K.-i.N.)
- Department of Neurochemistry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Nagoya 466-8550, Japan
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16132 Genoa, Italy;
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
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14
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Dysfunction of Trio GEF1 involves in excitatory/inhibitory imbalance and autism-like behaviors through regulation of interneuron migration. Mol Psychiatry 2021; 26:7621-7640. [PMID: 33963279 DOI: 10.1038/s41380-021-01109-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/24/2021] [Accepted: 04/08/2021] [Indexed: 02/03/2023]
Abstract
Autism spectrum disorders (ASDs) are a group of highly inheritable neurodevelopmental disorders. Functional mutations in TRIO, especially in the GEF1 domain, are strongly implicated in ASDs, whereas the underlying neurobiological pathogenesis and molecular mechanisms remain to be clarified. Here we characterize the abnormal morphology and behavior of embryonic migratory interneurons (INs) upon Trio deficiency or GEF1 mutation in mice, which are mediated by the Trio GEF1-Rac1 activation and involved in SDF1α/CXCR4 signaling. In addition, the migration deficits are specifically associated with altered neural microcircuit, decreased inhibitory neurotransmission, and autism-like behaviors, which are reminiscent of some features observed in patients with ASDs. Furthermore, restoring the excitatory/inhibitory (E/I) imbalance via activation of GABA signaling rescues autism-like deficits. Our findings demonstrate a critical role of Trio GEF1 mediated signaling in IN migration and E/I balance, which are related to autism-related behavioral phenotypes.
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15
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P-Rex1 Controls Sphingosine 1-Phosphate Receptor Signalling, Morphology, and Cell-Cycle Progression in Neuronal Cells. Cells 2021; 10:cells10092474. [PMID: 34572121 PMCID: PMC8469755 DOI: 10.3390/cells10092474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 09/15/2021] [Indexed: 11/30/2022] Open
Abstract
P-Rex1 is a guanine-nucleotide exchange factor (GEF) that activates Rac-type small G proteins in response to the stimulation of a range of receptors, particularly G protein-coupled receptors (GPCRs), to control cytoskeletal dynamics and other Rac-dependent cell responses. P-Rex1 is mainly expressed in leukocytes and neurons. Whereas its roles in leukocytes have been studied extensively, relatively little is known about its functions in neurons. Here, we used CRISPR/Cas9-mediated P-Rex1 deficiency in neuronal PC12 cells that stably overexpress the GPCR S1PR1, a receptor for sphingosine 1-phosphate (S1P), to investigate the role of P-Rex1 in neuronal GPCR signalling and cell responses. We show that P-Rex1 is required for the S1P-stimulated activation of Rac1 and Akt, basal Rac3 activity, and constitutive cAMP production in PC12-S1PR1 cells. The constitutive cAMP production was not due to increased expression levels of major neuronal adenylyl cyclases, suggesting that P-Rex1 may regulate adenylyl cyclase activity. P-Rex1 was required for maintenance of neurite protrusions and spreading in S1P-stimulated PC12-S1PR1 cells, as well as for cell-cycle progression and proliferation. In summary, we identified novel functional roles of P-Rex1 in neuronal Rac, Akt and cAMP signalling, as well as in neuronal cell-cycle progression and proliferation.
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16
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Guiler W, Koehler A, Boykin C, Lu Q. Pharmacological Modulators of Small GTPases of Rho Family in Neurodegenerative Diseases. Front Cell Neurosci 2021; 15:661612. [PMID: 34054432 PMCID: PMC8149604 DOI: 10.3389/fncel.2021.661612] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/08/2021] [Indexed: 12/22/2022] Open
Abstract
Classical Rho GTPases, including RhoA, Rac1, and Cdc42, are members of the Ras small GTPase superfamily and play essential roles in a variety of cellular functions. Rho GTPase signaling can be turned on and off by specific GEFs and GAPs, respectively. These features empower Rho GTPases and their upstream and downstream modulators as targets for scientific research and therapeutic intervention. Specifically, significant therapeutic potential exists for targeting Rho GTPases in neurodegenerative diseases due to their widespread cellular activity and alterations in neural tissues. This study will explore the roles of Rho GTPases in neurodegenerative diseases with focus on the applications of pharmacological modulators in recent discoveries. There have been exciting developments of small molecules, nonsteroidal anti-inflammatory drugs (NSAIDs), and natural products and toxins for each classical Rho GTPase category. A brief overview of each category followed by examples in their applications will be provided. The literature on their roles in various diseases [e.g., Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS), Frontotemporal dementia (FTD), and Multiple sclerosis (MS)] highlights the unique and broad implications targeting Rho GTPases for potential therapeutic intervention. Clearly, there is increasing knowledge of therapeutic promise from the discovery of pharmacological modulators of Rho GTPases for managing and treating these conditions. The progress is also accompanied by the recognition of complex Rho GTPase modulation where targeting its signaling can improve some aspects of pathogenesis while exacerbating others in the same disease model. Future directions should emphasize the importance of elucidating how different Rho GTPases work in concert and how they produce such widespread yet different cellular responses during neurodegenerative disease progression.
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Affiliation(s)
| | | | | | - Qun Lu
- Department of Anatomy and Cell Biology, The Harriet and John Wooten Laboratory for Alzheimer’s and Neurogenerative Diseases Research, Brody School of Medicine, East Carolina University, Greenville, NC, United States
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17
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Fan XC, Ma CN, Song JC, Liao ZH, Huang N, Liu X, Ma L. Rac1 Signaling in Amygdala Astrocytes Regulates Fear Memory Acquisition and Retrieval. Neurosci Bull 2021; 37:947-958. [PMID: 33909243 DOI: 10.1007/s12264-021-00677-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/09/2020] [Indexed: 11/25/2022] Open
Abstract
The importance of astrocytes in behavior control is increasingly appreciated, but little is known about the effects of their dynamic activity in regulating learning and memory. In the present study, we constructed AAVs of photoactivatable and photoinactivatable Ras-related C3 botulinum toxin substrate 1 (Rac1) under the mGFAP promoter, which enabled the manipulation of Rac1 activity in astrocytes by optical stimulation in free-moving mice. We found that both up-regulation and down-regulation of astrocytic Rac1 activity in the basolateral amygdala (BLA) attenuated memory acquisition in a fear conditioning mouse model. Meanwhile, neuronal activation in the BLA induced by memory acquisition was inhibited under both the up- and down-regulation of astrocytic Rac1 activity during training. In terms of the impact on fear memory retrieval, we found both up- and down-regulation of BLA astrocytic Rac1 activity impaired memory retrieval of fear conditioning and memory retrieval-induced neuronal activation. Notably, the effect of astrocytic Rac1 on memory retrieval was reversible. Our results demonstrate that the normal activity of astrocytic Rac1 is necessary for the activation of neurons and memory formation. Both activation and inactivation of astrocytic Rac1 activity in the BLA reduced the excitability of neurons, and thereby impaired fear memory acquisition and retrieval.
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Affiliation(s)
- Xiao-Cen Fan
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Chao-Nan Ma
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Jia-Chen Song
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Zhao-Hui Liao
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Nan Huang
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Xing Liu
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
| | - Lan Ma
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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18
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Erythropoietin Stimulates GABAergic Maturation in the Mouse Hippocampus. eNeuro 2021; 8:ENEURO.0006-21.2021. [PMID: 33495244 PMCID: PMC7890522 DOI: 10.1523/eneuro.0006-21.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 01/09/2021] [Indexed: 12/15/2022] Open
Abstract
Several neurodevelopmental disabilities are strongly associated with alterations in GABAergic transmission, and therapies to stimulate its normal development are lacking. Erythropoietin (EPO) is clinically used in neonatology to mitigate acute brain injury, and to stimulate neuronal maturation. Yet it remains unclear whether EPO can stimulate maturation of the GABAergic system. Here, with the use of a transgenic mouse line that constitutively overexpresses neuronal EPO (Tg21), we show that EPO stimulates postnatal GABAergic maturation in the hippocampus. We show an increase in hippocampal GABA-immunoreactive neurons, and postnatal elevation of interneurons expressing parvalbumin (PV), somatostatin (SST), and neuropeptide Y (NPY). Analysis of perineuronal net (PNN) formation and innervation of glutamatergic terminals onto PV+ cells, shows to be enhanced early in postnatal development. Additionally, an increase in GABAAergic synapse density and IPSCs in CA1 pyramidal cells from Tg21 mice is observed. Detection of EPO receptor (EPOR) mRNA was observed to be restricted to glutamatergic pyramidal cells and increased in Tg21 mice at postnatal day (P)7, along with reduced apoptosis. Our findings show that EPO can stimulate postnatal GABAergic maturation in the hippocampus, by increasing neuronal survival, modulating critical plasticity periods, and increasing synaptic transmission. Our data supports EPO’s clinical use to balance GABAergic dysfunction.
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Singh S, Singh TG, Rehni AK. An Insight into Molecular Mechanisms and Novel Therapeutic Approaches in Epileptogenesis. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2021; 19:750-779. [PMID: 32914725 DOI: 10.2174/1871527319666200910153827] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/15/2020] [Accepted: 07/16/2020] [Indexed: 11/22/2022]
Abstract
Epilepsy is the second most common neurological disease with abnormal neural activity involving the activation of various intracellular signalling transduction mechanisms. The molecular and system biology mechanisms responsible for epileptogenesis are not well defined or understood. Neuroinflammation, neurodegeneration and Epigenetic modification elicit epileptogenesis. The excessive neuronal activities in the brain are associated with neurochemical changes underlying the deleterious consequences of excitotoxicity. The prolonged repetitive excessive neuronal activities extended to brain tissue injury by the activation of microglia regulating abnormal neuroglia remodelling and monocyte infiltration in response to brain lesions inducing axonal sprouting contributing to neurodegeneration. The alteration of various downstream transduction pathways resulted in intracellular stress responses associating endoplasmic reticulum, mitochondrial and lysosomal dysfunction, activation of nucleases, proteases mediated neuronal death. The recently novel pharmacological agents modulate various receptors like mTOR, COX-2, TRK, JAK-STAT, epigenetic modulators and neurosteroids are used for attenuation of epileptogenesis. Whereas the various molecular changes like the mutation of the cell surface, nuclear receptor and ion channels focusing on repetitive episodic seizures have been explored by preclinical and clinical studies. Despite effective pharmacotherapy for epilepsy, the inadequate understanding of precise mechanisms, drug resistance and therapeutic failure are the current fundamental problems in epilepsy. Therefore, the novel pharmacological approaches evaluated for efficacy on experimental models of epilepsy need to be identified and validated. In addition, we need to understand the downstream signalling pathways of new targets for the treatment of epilepsy. This review emphasizes on the current state of novel molecular targets as therapeutic approaches and future directions for the management of epileptogenesis. Novel pharmacological approaches and clinical exploration are essential to make new frontiers in curing epilepsy.
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Affiliation(s)
- Shareen Singh
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | | | - Ashish Kumar Rehni
- Cerebral Vascular Disease Research Laboratories, Department of Neurology and Neuroscience Program, University of Miami School of Medicine, Miami, Florida 33101, United States
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20
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Cheng C, Song D, Wu Y, Liu B. RAC3 Promotes Proliferation, Migration and Invasion via PYCR1/JAK/STAT Signaling in Bladder Cancer. Front Mol Biosci 2020; 7:218. [PMID: 33062641 PMCID: PMC7488983 DOI: 10.3389/fmolb.2020.00218] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 08/04/2020] [Indexed: 12/20/2022] Open
Abstract
Background Bladder cancer (BCa) represents one of the most common malignant cancers with high incidence and mortality rates globally. Dysregulation of gene expression has been shown to play critical roles in cancer progression. RAC3 is up-regulated to play an oncogenic role in several cancers, however, the underlying mechanism of RAC3 in BCa is yet to be elucidated. Therefore, this study aimed to investigate the function and mechanism of RAC3 in BCa. Methods Bioinformatics analysis was employed to demonstrate the expression of RAC3 and PYCR1 in BCa tissues, as well as, its correlation with the overall survival rate of BCa patients. RT-qPCR was performed to detect and quantify the mRNA levels of RAC3 and PYCR1 in BCa cells and immortalized human bladder epithelial cells. MTT, colony formation and Transwell assays were employed to determine cell proliferation, migration, and invasion. Western blotting was performed to detect and quantity proteins expressed. Results Bioinformatics analysis showed that RAC3 was up-regulated in BCa tissues when compared to normal tissues. Patients with up-regulated RAC3 expression had lower overall survival than patients with down-regulated RAC3 expression. The mRNA level of RAC3 was higher in BCa cells than in immortalized human bladder epithelial cell. RAC3 promoted cell proliferation, migration, and invasion by activating Janus kinases (JAKs) and signal transducers and activators of transcription (STATs) signaling. Notably, RAC3 up-regulated PYCR1, which is positively correlated with RAC3, and thus played an oncogenic role in BCa cells. Moreover, we demonstrated that RAC3 overexpression activated JAK/STAT signaling via PYCR1 axis. Conclusion RAC3 promoted cell proliferation, migration, and invasion. This is likely due to its role in activating JAK/STAT signaling, which was mediated by PYCR1. This study provides a novel biomarker and target for diagnostic or therapeutic intervention for BCa.
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Affiliation(s)
- Chuanyu Cheng
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Dongkui Song
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yudong Wu
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Bingqian Liu
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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21
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Santiago M, Antunes C, Guedes M, Iacovino M, Kyba M, Reik W, Sousa N, Pinto L, Branco MR, Marques CJ. Tet3 regulates cellular identity and DNA methylation in neural progenitor cells. Cell Mol Life Sci 2020; 77:2871-2883. [PMID: 31646359 PMCID: PMC7326798 DOI: 10.1007/s00018-019-03335-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 09/26/2019] [Accepted: 10/03/2019] [Indexed: 12/21/2022]
Abstract
TET enzymes oxidize 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC), a process thought to be intermediary in an active DNA demethylation mechanism. Notably, 5hmC is highly abundant in the brain and in neuronal cells. Here, we interrogated the function of Tet3 in neural precursor cells (NPCs), using a stable and inducible knockdown system and an in vitro neural differentiation protocol. We show that Tet3 is upregulated during neural differentiation, whereas Tet1 is downregulated. Surprisingly, Tet3 knockdown led to a de-repression of pluripotency-associated genes such as Oct4, Nanog or Tcl1, with concomitant hypomethylation. Moreover, in Tet3 knockdown NPCs, we observed the appearance of OCT4-positive cells forming cellular aggregates, suggesting de-differentiation of the cells. Notably, Tet3 KD led to a genome-scale loss of DNA methylation and hypermethylation of a smaller number of CpGs that are located at neurogenesis-related genes and at imprinting control regions (ICRs) of Peg10, Zrsr1 and Mcts2 imprinted genes. Overall, our results suggest that TET3 is necessary to maintain silencing of pluripotency genes and consequently neural stem cell identity, possibly through regulation of DNA methylation levels in neural precursor cells.
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Affiliation(s)
- Mafalda Santiago
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
| | - Claudia Antunes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
| | - Marta Guedes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
| | - Michelina Iacovino
- Lillehei Heart Institute and Department of Pediatrics, University of Minnesota, Minneapolis, MN, 55455, USA
- Division of Medical Genetics, Department of Pediatrics, Harbor UCLA Medical Center, Los Angeles Biomedical Research Institute, Torrance, CA, 90502, USA
| | - Michael Kyba
- Lillehei Heart Institute and Department of Pediatrics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Wolf Reik
- Epigenetics Programme, The Babraham Institute, Cambridge, CB22 3AT, UK
- The Wellcome Trust Sanger Institute, Cambridge, CB10 1SA, UK
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
| | - Luísa Pinto
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal
| | - Miguel R Branco
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK.
| | - C Joana Marques
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal.
- ICVS/3B's-PT Government Associate Laboratory, 4710-057, Braga/Guimarães, Portugal.
- Department of Genetics, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal.
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal.
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22
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Barbosa S, Greville-Heygate S, Bonnet M, Godwin A, Fagotto-Kaufmann C, Kajava AV, Laouteouet D, Mawby R, Wai HA, Dingemans AJ, Hehir-Kwa J, Willems M, Capri Y, Mehta SG, Cox H, Goudie D, Vansenne F, Turnpenny P, Vincent M, Cogné B, Lesca G, Hertecant J, Rodriguez D, Keren B, Burglen L, Gérard M, Putoux A, Cantagrel V, Siquier-Pernet K, Rio M, Banka S, Sarkar A, Steeves M, Parker M, Clement E, Moutton S, Tran Mau-Them F, Piton A, de Vries BB, Guille M, Debant A, Schmidt S, Baralle D, Baralle D. Opposite Modulation of RAC1 by Mutations in TRIO Is Associated with Distinct, Domain-Specific Neurodevelopmental Disorders. Am J Hum Genet 2020; 106:338-355. [PMID: 32109419 PMCID: PMC7058823 DOI: 10.1016/j.ajhg.2020.01.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/27/2020] [Indexed: 12/13/2022] Open
Abstract
The Rho-guanine nucleotide exchange factor (RhoGEF) TRIO acts as a key regulator of neuronal migration, axonal outgrowth, axon guidance, and synaptogenesis by activating the GTPase RAC1 and modulating actin cytoskeleton remodeling. Pathogenic variants in TRIO are associated with neurodevelopmental diseases, including intellectual disability (ID) and autism spectrum disorders (ASD). Here, we report the largest international cohort of 24 individuals with confirmed pathogenic missense or nonsense variants in TRIO. The nonsense mutations are spread along the TRIO sequence, and affected individuals show variable neurodevelopmental phenotypes. In contrast, missense variants cluster into two mutational hotspots in the TRIO sequence, one in the seventh spectrin repeat and one in the RAC1-activating GEFD1. Although all individuals in this cohort present with developmental delay and a neuro-behavioral phenotype, individuals with a pathogenic variant in the seventh spectrin repeat have a more severe ID associated with macrocephaly than do most individuals with GEFD1 variants, who display milder ID and microcephaly. Functional studies show that the spectrin and GEFD1 variants cause a TRIO-mediated hyper- or hypo-activation of RAC1, respectively, and we observe a striking correlation between RAC1 activation levels and the head size of the affected individuals. In addition, truncations in TRIO GEFD1 in the vertebrate model X. tropicalis induce defects that are concordant with the human phenotype. This work demonstrates distinct clinical and molecular disorders clustering in the GEFD1 and seventh spectrin repeat domains and highlights the importance of tight control of TRIO-RAC1 signaling in neuronal development.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Diana Baralle
- Wessex Clinical Genetics, University Hospital Southampton National Health Service Foundation Trust, Southampton SO16 5YA, UK; Human Development and Health, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
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23
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Russo I, Gavello D, Menna E, Vandael D, Veglia C, Morello N, Corradini I, Focchi E, Alfieri A, Angelini C, Bianchi FT, Morellato A, Marcantoni A, Sassoè-Pognetto M, Ottaviani MM, Yekhlef L, Giustetto M, Taverna S, Carabelli V, Matteoli M, Carbone E, Turco E, Defilippi P. p140Cap Regulates GABAergic Synaptogenesis and Development of Hippocampal Inhibitory Circuits. Cereb Cortex 2020; 29:91-105. [PMID: 29161354 DOI: 10.1093/cercor/bhx306] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/23/2017] [Indexed: 01/19/2023] Open
Abstract
The neuronal scaffold protein p140Cap was investigated during hippocampal network formation. p140Cap is present in presynaptic GABAergic terminals and its genetic depletion results in a marked alteration of inhibitory synaptic activity. p140Cap-/- cultured neurons display higher frequency of miniature inhibitory postsynaptic currents (mIPSCs) with no changes of their mean amplitude. Consistent with a potential presynaptic alteration of basal GABA release, p140Cap-/- neurons exhibit a larger synaptic vesicle readily releasable pool, without any variation of single GABAA receptor unitary currents and number of postsynaptic channels. Furthermore, p140Cap-/- neurons show a premature and enhanced network synchronization and appear more susceptible to 4-aminopyridine-induced seizures in vitro and to kainate-induced seizures in vivo. The hippocampus of p140Cap-/- mice showed a significant increase in the number of both inhibitory synapses and of parvalbumin- and somatostatin-expressing interneurons. Specific deletion of p140Cap in forebrain interneurons resulted in increased susceptibility to in vitro epileptic events and increased inhibitory synaptogenesis, comparable to those observed in p140Cap-/- mice. Altogether, our data demonstrate that p140Cap finely tunes inhibitory synaptogenesis and GABAergic neurotransmission, thus regulating the establishment and maintenance of the proper hippocampal excitatory/inhibitory balance.
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Affiliation(s)
- Isabella Russo
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Daniela Gavello
- Department of Drug Science, University of Torino, Torino, Italy.,NIS Centre of Excellence, Torino, Italy
| | - Elisabetta Menna
- Institute of Neuroscience, CNR, Milano, Italy.,Istituto Clinico Humanitas, IRCCS, Rozzano, Italy
| | - David Vandael
- Department of Drug Science, University of Torino, Torino, Italy.,NIS Centre of Excellence, Torino, Italy
| | - Carola Veglia
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Noemi Morello
- Department of Neuroscience, University of Torino, Torino, Italy
| | - Irene Corradini
- Institute of Neuroscience, CNR, Milano, Italy.,Istituto Clinico Humanitas, IRCCS, Rozzano, Italy
| | | | - Annalisa Alfieri
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Costanza Angelini
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Federico Tommaso Bianchi
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy
| | - Alessandro Morellato
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Andrea Marcantoni
- Department of Drug Science, University of Torino, Torino, Italy.,NIS Centre of Excellence, Torino, Italy
| | - Marco Sassoè-Pognetto
- Department of Neuroscience, University of Torino, Torino, Italy.,National Institute of Neuroscience-Italy, Torino, Italy
| | | | - Latefa Yekhlef
- Division of Neuroscience, San Raffaele Scientific Institute, Milano, Italy
| | - Maurizio Giustetto
- Department of Neuroscience, University of Torino, Torino, Italy.,National Institute of Neuroscience-Italy, Torino, Italy
| | - Stefano Taverna
- Division of Neuroscience, San Raffaele Scientific Institute, Milano, Italy
| | - Valentina Carabelli
- Department of Drug Science, University of Torino, Torino, Italy.,NIS Centre of Excellence, Torino, Italy
| | - Michela Matteoli
- Institute of Neuroscience, CNR, Milano, Italy.,Istituto Clinico Humanitas, IRCCS, Rozzano, Italy
| | - Emilio Carbone
- Department of Drug Science, University of Torino, Torino, Italy.,NIS Centre of Excellence, Torino, Italy
| | - Emilia Turco
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Paola Defilippi
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
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24
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mTOR-Related Cell-Clearing Systems in Epileptic Seizures, an Update. Int J Mol Sci 2020; 21:ijms21051642. [PMID: 32121250 PMCID: PMC7084443 DOI: 10.3390/ijms21051642] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 02/06/2023] Open
Abstract
Recent evidence suggests that autophagy impairment is implicated in the epileptogenic mechanisms downstream of mTOR hyperactivation. This holds true for a variety of genetic and acquired epileptic syndromes besides malformations of cortical development which are classically known as mTORopathies. Autophagy suppression is sufficient to induce epilepsy in experimental models, while rescuing autophagy prevents epileptogenesis, improves behavioral alterations, and provides neuroprotection in seizure-induced neuronal damage. The implication of autophagy in epileptogenesis and maturation phenomena related to seizure activity is supported by evidence indicating that autophagy is involved in the molecular mechanisms which are implicated in epilepsy. In general, mTOR-dependent autophagy regulates the proliferation and migration of inter-/neuronal cortical progenitors, synapse development, vesicular release, synaptic plasticity, and importantly, synaptic clustering of GABAA receptors and subsequent excitatory/inhibitory balance in the brain. Similar to autophagy, the ubiquitin–proteasome system is regulated downstream of mTOR, and it is implicated in epileptogenesis. Thus, mTOR-dependent cell-clearing systems are now taking center stage in the field of epilepsy. In the present review, we discuss such evidence in a variety of seizure-related disorders and models. This is expected to provide a deeper insight into the molecular mechanisms underlying seizure activity.
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25
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The Rac3 GTPase in Neuronal Development, Neurodevelopmental Disorders, and Cancer. Cells 2019; 8:cells8091063. [PMID: 31514269 PMCID: PMC6770886 DOI: 10.3390/cells8091063] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/06/2019] [Accepted: 09/08/2019] [Indexed: 12/23/2022] Open
Abstract
Rho family small guanosine triphosphatases (GTPases) are important regulators of the cytoskeleton, and are critical in many aspects of cellular and developmental biology, as well as in pathological processes such as intellectual disability and cancer. Of the three members of the family, Rac3 has a more restricted expression in normal tissues compared to the ubiquitous member of the family, Rac1. The Rac3 polypeptide is highly similar to Rac1, and orthologues of the gene for Rac3 have been found only in vertebrates, indicating the late appearance of this gene during evolution. Increasing evidence over the past few years indicates that Rac3 plays an important role in neuronal development and in tumor progression, with specificities that distinguish the functions of Rac3 from the established functions of Rac1 in these processes. Here, results highlighting the importance of Rac3 in distinct aspects of neuronal development and tumor cell biology are presented, in support of the non-redundant role of different members of the two Rac GTPases in physiological and pathological processes.
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26
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Pennucci R, Gucciardi I, de Curtis I. Rac1 and Rac3 GTPases differently influence the morphological maturation of dendritic spines in hippocampal neurons. PLoS One 2019; 14:e0220496. [PMID: 31369617 PMCID: PMC6675090 DOI: 10.1371/journal.pone.0220496] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/17/2019] [Indexed: 11/24/2022] Open
Abstract
The Rac1 and Rac3 GTPases are co-expressed in the developing nervous system, where they are involved in different aspects of neuronal development, including the formation of synapses. The deletion of both Rac genes determines a stronger reduction of dendritic spines in vitro compared to the knockout of either gene, indicating that Rac1 and Rac3 play a synergistic role in the formation of these structures. Here, we have addressed the role of each GTPase in the formation of dendritic spines by overexpressing either Rac1 or Rac3 in wildtype neurons, or by re-expressing either GTPase in double knockout hippocampal cultures. We show that the Rac3 protein is expressed with Rac1 in developing hippocampal neurons. Overexpression of either GTPase in WT neurons increases the density of dendritic spines, suggesting the involvement of both GTPases in their formation. We also found that the re-expression of either Rac1 or Rac3 in double knockout neurons is sufficient to restore spinogenesis. Rac1 is significantly more efficient than Rac3 in restoring the formation of spines. On the other hand the quantitative analysis in neurons overexpressing or re-expressing either GTPase shows that Rac3 induces a more pronounced increase in the size of the spines compared to Rac1. These enlarged spines form morphological synapses identified by the juxtaposition of postsynaptic and presynaptic markers. Thus, while Rac1 appears more efficient in inducing the formation of mature spines, Rac3 is more efficient in promoting their enlargement. Our study highlights specific roles of Rac1 and Rac3, which may be functionally relevant also to synaptic plasticity.
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Affiliation(s)
- Roberta Pennucci
- San Raffaele—Vita-Salute University and San Raffaele Scientific institute, Cell Adhesion Unit, Division of Neuroscience, Milano, Italy
| | - Irene Gucciardi
- San Raffaele—Vita-Salute University and San Raffaele Scientific institute, Cell Adhesion Unit, Division of Neuroscience, Milano, Italy
| | - Ivan de Curtis
- San Raffaele—Vita-Salute University and San Raffaele Scientific institute, Cell Adhesion Unit, Division of Neuroscience, Milano, Italy
- * E-mail:
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27
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Ueyama T, Sakuma M, Nakatsuji M, Uebi T, Hamada T, Aiba A, Saito N. Rac-Dependent Signaling from Keratinocytes Promotes Differentiation of Intradermal White Adipocytes. J Invest Dermatol 2019; 140:75-84.e6. [PMID: 31351086 DOI: 10.1016/j.jid.2019.06.140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 06/23/2019] [Accepted: 06/28/2019] [Indexed: 01/10/2023]
Abstract
Rac signaling affects numerous downstream targets in vitro; however, few studies have established in vivo levels. We generated mice with a single knockout (KO) of Rac1 (Keratin5(K5)-Cre;Rac1flox/flox, Rac1-KO) and double KO of Rac1 and Rac3 (K5-Cre;Rac1flox/flox;Rac3-/-, Rac1/Rac3-DKO) in keratinocytes. The hairless phenotype in Rac1-KO mice was markedly exacerbated in Rac1/Rac3-DKO mice. Strikingly, Rac1-KO mice exhibited thinner dermal white adipose tissue, which was considerably further reduced in Rac1/Rac3-DKO mice. DNA microarray using primary keratinocytes from Rac1/Rac3-DKO mice exhibited decreased mRNA levels of Bmp2, Bmp5, Fgf20, Fgf21, Fgfbp1, and Pdgfα. Combinational treatment with bone morphogenetic protein (BMP) 2 and fibroblast growth factor (FGF) 21 in culture medium, but not individual purified recombinant proteins, could differentiate 3T3-L1 fibroblasts into adipocytes, as could culture media from primary keratinocytes. Conversely, addition of anti-BMP2 or anti-FGF21 antibodies into the culture medium inhibited fibroblast differentiation. In addition, BMP2 and FGF21 treatment promoted adipocyte differentiation only of rat primary white adipocyte precursors but not rat primary brown adipocyte precursors. Furthermore, BMP2 and FGF21 treatment enhanced adipogenesis of normal human dermal fibroblasts. Notably, brown adipogenesis promoted by FGF21 was inhibited by BMP2. Thus, we propose a complex paracrine pathway from keratinocytes to intradermal pre-adipocytes, which functions as a Rac-dependent modulator of both white and brown adipogenesis.
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Affiliation(s)
- Takehiko Ueyama
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan.
| | - Megumi Sakuma
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan
| | - Mio Nakatsuji
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan
| | - Tatsuya Uebi
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan
| | - Takeshi Hamada
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan
| | - Atsu Aiba
- Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Naoaki Saito
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan
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28
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Ito H, Morishita R, Mizuno M, Tabata H, Nagata KI. Rho family GTPases, Rac and Cdc42, control the localization of neonatal dentate granule cells during brain development. Hippocampus 2018; 29:569-578. [PMID: 30387892 DOI: 10.1002/hipo.23047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 10/01/2018] [Accepted: 10/15/2018] [Indexed: 11/09/2022]
Abstract
The hippocampus is generally considered as a brain center for learning and memory. We have recently established an electroporation-mediated gene transfer method to investigate the development of neonatal dentate granule cells in vivo. Using this new technique, we introduced knockdown vectors against Rac1 small GTPase into precursors for dentate granule cells at postnatal day 0. After 21 days, Rac1-deficient cells were frequently mispositioned between the granule cell layer (GCL) and hilus. About 60% of these mislocalized cells expressed a dentate granule cell marker, Prox1. Both the dendritic spine density and the ratio of mature spine were reduced when Rac1 was silenced. Notably, the deficient cells have immature thin processes during migrating in the early neonatal period. Knockdown of another Rac isoform, Rac3, also resulted in mislocalization of neonatally born dentate granule cells. In addition, knockdown of Cdc42, another Rho family protein, also caused mislocalization of the cell, although the effects were moderate compared to Rac1 and 3. Despite the ectopic localization, Rac3- or Cdc42-disrupted mispositioned cells expressed Prox1. These results indicate that Rho signaling pathways differentially regulate the proper localization and differentiation of dentate granule cells.
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Affiliation(s)
- Hidenori Ito
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi, Japan
| | - Rika Morishita
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi, Japan
| | - Makoto Mizuno
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi, Japan
| | - Hidenori Tabata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi, Japan
| | - Koh-Ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi, Japan.,Department of Neurochemistry, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Rho GTPases in Intellectual Disability: From Genetics to Therapeutic Opportunities. Int J Mol Sci 2018; 19:ijms19061821. [PMID: 29925821 PMCID: PMC6032284 DOI: 10.3390/ijms19061821] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/14/2018] [Accepted: 06/16/2018] [Indexed: 12/22/2022] Open
Abstract
Rho-class small GTPases are implicated in basic cellular processes at nearly all brain developmental steps, from neurogenesis and migration to axon guidance and synaptic plasticity. GTPases are key signal transducing enzymes that link extracellular cues to the neuronal responses required for the construction of neuronal networks, as well as for synaptic function and plasticity. Rho GTPases are highly regulated by a complex set of activating (GEFs) and inactivating (GAPs) partners, via protein:protein interactions (PPI). Misregulated RhoA, Rac1/Rac3 and cdc42 activity has been linked with intellectual disability (ID) and other neurodevelopmental conditions that comprise ID. All genetic evidences indicate that in these disorders the RhoA pathway is hyperactive while the Rac1 and cdc42 pathways are consistently hypoactive. Adopting cultured neurons for in vitro testing and specific animal models of ID for in vivo examination, the endophenotypes associated with these conditions are emerging and include altered neuronal networking, unbalanced excitation/inhibition and altered synaptic activity and plasticity. As we approach a clearer definition of these phenotype(s) and the role of hyper- and hypo-active GTPases in the construction of neuronal networks, there is an increasing possibility that selective inhibitors and activators might be designed via PPI, or identified by screening, that counteract the misregulation of small GTPases and result in alleviation of the cognitive condition. Here we review all knowledge in support of this possibility.
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Hyperactivity of Rac1-GTPase pathway impairs neuritogenesis of cortical neurons by altering actin dynamics. Sci Rep 2018; 8:7254. [PMID: 29740022 PMCID: PMC5940682 DOI: 10.1038/s41598-018-25354-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 04/18/2018] [Indexed: 01/10/2023] Open
Abstract
The small-GTPase Rac1 is a key molecular regulator linking extracellular signals to actin cytoskeleton dynamics. Loss-of-function mutations in RAC1 and other genes of the Rac signaling pathway have been implicated in the pathogenesis of Intellectual Disability (ID). The Rac1 activity is negatively controlled by GAP proteins, however the effect of Rac1 hyperactivity on neuronal networking in vivo has been poorly studied. ArhGAP15 is a Rac-specific negative regulator, expressed in the main subtypes of pyramidal cortical neurons. In the absence of ArhGAP15, cortical pyramidal neurons show defective neuritogenesis, delayed axonal elongation, reduced dendritic branching, both in vitro and in vivo. These phenotypes are associated with altered actin dynamics at the growth cone due to increased activity of the PAK-LIMK pathway and hyperphosphorylation of ADF/cofilin. These results can be explained by shootin1 hypo-phosphorylation and uncoupling with the adhesion system. Functionally, ArhGAP15−/− mice exhibit decreased synaptic density, altered electroencephalographic rhythms and cognitive deficits. These data suggest that both hypo- and hyperactivation of the Rac pathway due to mutations in Rac1 regulators can result in conditions of ID, and that a tight regulation of Rac1 activity is required to attain the full complexity of the cortical networks.
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31
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Franchi SA, Macco R, Astro V, Tonoli D, Savino E, Valtorta F, Sala K, Botta M, de Curtis I. A Method to Culture GABAergic Interneurons Derived from the Medial Ganglionic Eminence. Front Cell Neurosci 2018; 11:423. [PMID: 29358905 PMCID: PMC5766683 DOI: 10.3389/fncel.2017.00423] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 12/18/2017] [Indexed: 11/13/2022] Open
Abstract
Understanding the mechanisms guiding interneuron development is a central aspect of the current research on cortical/hippocampal interneurons, which is highly relevant to brain function and pathology. In this methodological study we have addressed the setup of protocols for the reproducible culture of dissociated cells from murine medial ganglionic eminences (MGEs), to provide a culture system for the analysis of interneurons in vitro. This study includes the detailed protocols for the preparation of the dissociated cells, and for their culture on optimal substrates for cell migration or differentiation. These cultures enriched in interneurons may allow the investigation of the migratory behavior of interneuron precursors and their differentiation in vitro, up to the formation of morphologically identifiable GABAergic synapses. Live imaging of MGE-derived cells plated on proper substrates shows that they are useful to study the migratory behavior of the precursors, as well as the behavior of growth cones during the development of neurites. Most MGE-derived precursors develop into polarized GABAergic interneurons as determined by axonal, dendritic, and GABAergic markers. We present also a comparison of cells from WT and mutant mice as a proof of principle for the use of these cultures for the analysis of the migration and differentiation of GABAergic cells with different genetic backgrounds. The culture enriched in interneurons described here represents a useful experimental system to examine in a relatively easy and fast way the morpho-functional properties of these cells under physiological or pathological conditions, providing a powerful tool to complement the studies in vivo.
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Affiliation(s)
- Sira A Franchi
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Romina Macco
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Veronica Astro
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Diletta Tonoli
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Elisa Savino
- Neuropsychopharmacology Unit, Division of Neuroscience, San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Flavia Valtorta
- Neuropsychopharmacology Unit, Division of Neuroscience, San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Kristyna Sala
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Martina Botta
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
| | - Ivan de Curtis
- Cell Adhesion Unit San Raffaele Scientific Institute and San Raffaele University, Milan, Italy
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32
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Donnelly SK, Cabrera R, Mao SPH, Christin JR, Wu B, Guo W, Bravo-Cordero JJ, Condeelis JS, Segall JE, Hodgson L. Rac3 regulates breast cancer invasion and metastasis by controlling adhesion and matrix degradation. J Cell Biol 2017; 216:4331-4349. [PMID: 29061650 PMCID: PMC5716284 DOI: 10.1083/jcb.201704048] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/28/2017] [Accepted: 09/25/2017] [Indexed: 01/21/2023] Open
Abstract
The initial step of metastasis is the local invasion of tumor cells into the surrounding tissue. Invadopodia are actin-based protrusions that mediate the matrix degradation necessary for invasion and metastasis of tumor cells. We demonstrate that Rac3 GTPase is critical for integrating the adhesion of invadopodia to the extracellular matrix (ECM) with their ability to degrade the ECM in breast tumor cells. We identify two pathways at invadopodia important for integrin activation and delivery of matrix metalloproteinases: through the upstream recruiter CIB1 as well as the downstream effector GIT1. Rac3 activity, at and surrounding invadopodia, is controlled by Vav2 and βPIX. These guanine nucleotide exchange factors regulate the spatiotemporal dynamics of Rac3 activity, impacting GIT1 localization. Moreover, the GTPase-activating function of GIT1 toward the vesicular trafficking regulator Arf6 GTPase is required for matrix degradation. Importantly, Rac3 regulates the ability of tumor cells to metastasize in vivo. The Rac3-dependent mechanisms we show in this study are critical for balancing proteolytic activity and adhesive activity to achieve a maximally invasive phenotype.
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Affiliation(s)
- Sara K Donnelly
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY
| | - Ramon Cabrera
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY
| | - Serena P H Mao
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY
| | - John R Christin
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY
| | - Bin Wu
- Biophysics and Biophysical Chemistry, School of Medicine, Johns Hopkins University, Baltimore, MD
| | - Wenjun Guo
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY
| | - Jose Javier Bravo-Cordero
- Department of Medicine, Division of Hematology and Medical Oncology, Icahn School of Medicine, Tisch Cancer Institute at Mount Sinai, New York, NY
| | - John S Condeelis
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY
| | - Jeffrey E Segall
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY
| | - Louis Hodgson
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY
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33
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Franchi SA, Astro V, Macco R, Tonoli D, Barnier JV, Botta M, de Curtis I. Identification of a Protein Network Driving Neuritogenesis of MGE-Derived GABAergic Interneurons. Front Cell Neurosci 2016; 10:289. [PMID: 28066185 PMCID: PMC5174131 DOI: 10.3389/fncel.2016.00289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/02/2016] [Indexed: 12/27/2022] Open
Abstract
Interneurons are essential modulators of brain activity and their abnormal maturation may lead to neural and intellectual disabilities. Here we show that cultures derived from murine medial ganglionic eminences (MGEs) produce virtually pure, polarized γ-aminobutyric acid (GABA)-ergic interneurons that can form morphologically identifiable inhibitory synapses. We show that Rac GTPases and a protein complex including the GIT family scaffold proteins are expressed during maturation in vitro, and are required for the normal development of neurites. GIT1 promotes neurite extension in a conformation-dependent manner, while affecting its interaction with specific partners reduces neurite branching. Proteins of the GIT network are concentrated at growth cones, and interaction mutants may affect growth cone behavior. Our findings identify the PIX/GIT1/liprin-α1/ERC1 network as critical for the regulation of interneuron neurite differentiation in vitro, and show that these cultures represent a valuable system to identify the molecular mechanisms driving the maturation of cortical/hippocampal interneurons.
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Affiliation(s)
- Sira A Franchi
- Cell Adhesion Unit, Division of Neuroscience, San Raffaele Scientific Institute and San Raffaele University Milano, Italy
| | - Veronica Astro
- Cell Adhesion Unit, Division of Neuroscience, San Raffaele Scientific Institute and San Raffaele University Milano, Italy
| | - Romina Macco
- Cell Adhesion Unit, Division of Neuroscience, San Raffaele Scientific Institute and San Raffaele University Milano, Italy
| | - Diletta Tonoli
- Cell Adhesion Unit, Division of Neuroscience, San Raffaele Scientific Institute and San Raffaele University Milano, Italy
| | - Jean-Vianney Barnier
- Neuroscience Paris-Saclay Institute, UMR 9197, Centre National de la Recherche Scientifique-Université Paris-Sud Orsay, France
| | - Martina Botta
- Cell Adhesion Unit, Division of Neuroscience, San Raffaele Scientific Institute and San Raffaele University Milano, Italy
| | - Ivan de Curtis
- Cell Adhesion Unit, Division of Neuroscience, San Raffaele Scientific Institute and San Raffaele University Milano, Italy
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Zamboni V, Armentano M, Sarò G, Ciraolo E, Ghigo A, Germena G, Umbach A, Valnegri P, Passafaro M, Carabelli V, Gavello D, Bianchi V, D'Adamo P, de Curtis I, El-Assawi N, Mauro A, Priano L, Ferri N, Hirsch E, Merlo GR. Disruption of ArhGAP15 results in hyperactive Rac1, affects the architecture and function of hippocampal inhibitory neurons and causes cognitive deficits. Sci Rep 2016; 6:34877. [PMID: 27713499 PMCID: PMC5054378 DOI: 10.1038/srep34877] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 09/19/2016] [Indexed: 11/12/2022] Open
Abstract
During brain development, the small GTPases Rac1/Rac3 play key roles in neuronal migration, neuritogenesis, synaptic formation and plasticity, via control of actin cytoskeleton dynamic. Their activity is positively and negatively regulated by GEFs and GAPs molecules, respectively. However their in vivo roles are poorly known. The ArhGAP15 gene, coding for a Rac-specific GAP protein, is expressed in both excitatory and inhibitory neurons of the adult hippocampus, and its loss results in the hyperactivation of Rac1/Rac3. In the CA3 and dentate gyrus (DG) regions of the ArhGAP15 mutant hippocampus the CR+, PV+ and SST+ inhibitory neurons are reduced in number, due to reduced efficiency and directionality of their migration, while pyramidal neurons are unaffected. Loss of ArhGAP15 alters neuritogenesis and the balance between excitatory and inhibitory synapses, with a net functional result consisting in increased spike frequency and bursts, accompanied by poor synchronization. Thus, the loss of ArhGAP15 mainly impacts on interneuron-dependent inhibition. Adult ArhGAP15−/− mice showed defective hippocampus-dependent functions such as working and associative memories. These findings indicate that a normal architecture and function of hippocampal inhibitory neurons is essential for higher hippocampal functions, and is exquisitely sensitive to ArhGAP15-dependent modulation of Rac1/Rac3.
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Affiliation(s)
- Valentina Zamboni
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Maria Armentano
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Gabriella Sarò
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Elisa Ciraolo
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Alessandra Ghigo
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Giulia Germena
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Alessandro Umbach
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | | | | | | | | | - Veronica Bianchi
- IRCSS San Raffaele Scientific Institute and San Raffaele University, Division of Neuroscience, Milano, Italy
| | - Patrizia D'Adamo
- IRCSS San Raffaele Scientific Institute and San Raffaele University, Division of Neuroscience, Milano, Italy
| | - Ivan de Curtis
- IRCSS San Raffaele Scientific Institute and San Raffaele University, Division of Neuroscience, Milano, Italy
| | - Nadia El-Assawi
- Department of Neurosciences, University of Turin &Div. of Neurology and Neurorehabilitation, S.Giuseppe Hospital, Istituto Auxologico Italiano IRCCS, Piancavallo (VB), Italy
| | - Alessandro Mauro
- Department of Neurosciences, University of Turin &Div. of Neurology and Neurorehabilitation, S.Giuseppe Hospital, Istituto Auxologico Italiano IRCCS, Piancavallo (VB), Italy
| | - Lorenzo Priano
- Department of Neurosciences, University of Turin &Div. of Neurology and Neurorehabilitation, S.Giuseppe Hospital, Istituto Auxologico Italiano IRCCS, Piancavallo (VB), Italy
| | - Nicola Ferri
- Department of Pharmaceutical and Pharmacological Science, University of Padova, Italy
| | - Emilio Hirsch
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Giorgio R Merlo
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
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35
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Pennucci R, Talpo F, Astro V, Montinaro V, Morè L, Cursi M, Castoldi V, Chiaretti S, Bianchi V, Marenna S, Cambiaghi M, Tonoli D, Leocani L, Biella G, D'Adamo P, de Curtis I. Loss of Either Rac1 or Rac3 GTPase Differentially Affects the Behavior of Mutant Mice and the Development of Functional GABAergic Networks. Cereb Cortex 2015; 26:873-890. [PMID: 26582364 PMCID: PMC4712809 DOI: 10.1093/cercor/bhv274] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Rac GTPases regulate the development of cortical/hippocampal GABAergic interneurons by affecting the early development and migration of GABAergic precursors. We have addressed the function of Rac1 and Rac3 proteins during the late maturation of hippocampal interneurons. We observed specific phenotypic differences between conditional Rac1 and full Rac3 knockout mice. Rac1 deletion caused greater generalized hyperactivity and cognitive impairment compared with Rac3 deletion. This phenotype matched with a more evident functional impairment of the inhibitory circuits in Rac1 mutants, showing higher excitability and reduced spontaneous inhibitory currents in the CA hippocampal pyramidal neurons. Morphological analysis confirmed a differential modification of the inhibitory circuits: deletion of either Rac caused a similar reduction of parvalbumin-positive inhibitory terminals in the pyramidal layer. Intriguingly, cannabinoid receptor-1-positive terminals were strongly increased only in the CA1 of Rac1-depleted mice. This increase may underlie the stronger electrophysiological defects in this mutant. Accordingly, incubation with an antagonist for cannabinoid receptors partially rescued the reduction of spontaneous inhibitory currents in the pyramidal cells of Rac1 mutants. Our results show that Rac1 and Rac3 have independent roles in the formation of GABAergic circuits, as highlighted by the differential effects of their deletion on the late maturation of specific populations of interneurons.
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Affiliation(s)
| | - Francesca Talpo
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Italy
| | | | | | - Lorenzo Morè
- Molecular Genetics of Mental Retardation Unit, Division of Neuroscience, IRCSS San Raffaele Scientific Institute, Milano, Italy
| | - Marco Cursi
- Experimental Neurophysiology Unit, INSPE-Institute of Experimental Neurology, Division of Neuroscience, IRCSS San Raffaele Scientific Institute and San Raffaele University, Milano 20132, Italy
| | - Valerio Castoldi
- Experimental Neurophysiology Unit, INSPE-Institute of Experimental Neurology, Division of Neuroscience, IRCSS San Raffaele Scientific Institute and San Raffaele University, Milano 20132, Italy
| | | | - Veronica Bianchi
- Molecular Genetics of Mental Retardation Unit, Division of Neuroscience, IRCSS San Raffaele Scientific Institute, Milano, Italy
| | - Silvia Marenna
- Experimental Neurophysiology Unit, INSPE-Institute of Experimental Neurology, Division of Neuroscience, IRCSS San Raffaele Scientific Institute and San Raffaele University, Milano 20132, Italy
| | - Marco Cambiaghi
- Experimental Neurophysiology Unit, INSPE-Institute of Experimental Neurology, Division of Neuroscience, IRCSS San Raffaele Scientific Institute and San Raffaele University, Milano 20132, Italy
| | | | - Letizia Leocani
- Experimental Neurophysiology Unit, INSPE-Institute of Experimental Neurology, Division of Neuroscience, IRCSS San Raffaele Scientific Institute and San Raffaele University, Milano 20132, Italy
| | - Gerardo Biella
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Italy
| | - Patrizia D'Adamo
- Molecular Genetics of Mental Retardation Unit, Division of Neuroscience, IRCSS San Raffaele Scientific Institute, Milano, Italy
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Abstract
In the last decade, several mouse models for RhoA, Rac1, and Cdc42 have emerged and have contributed a great deal to understanding the precise functions of Rho GTPases at early stages of development. This review summarizes our current knowledge of various mouse models of tissue-specific ablation of Cdc42, Rac1, and RhoA with emphasis on early embryogenesis, epithelial and skin morphogenesis, tubulogenesis, development of the central nervous system, and limb development.
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Affiliation(s)
- Philippe M Duquette
- a McGill University ; Department of Anatomy and Cell Biology ; Montreal , QC Canada
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37
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Donnelly SK, Bravo-Cordero JJ, Hodgson L. Rho GTPase isoforms in cell motility: Don't fret, we have FRET. Cell Adh Migr 2015; 8:526-34. [PMID: 25482645 PMCID: PMC4594258 DOI: 10.4161/cam.29712] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The Rho-family of p21 small GTPases are directly linked to the regulation of actin-based motile machinery and play a key role in the control of cell migration. Aside from the original and most well-characterized canonical Rho GTPases RhoA, Rac1, and Cdc42, numerous isoforms of these key proteins have been identified and shown to have specific roles in regulating various cellular motility processes. The major difficulty in addressing these isoform-specific effects is that isoforms typically contain highly similar primary amino acid sequences and thus are able to interact with the same upstream regulators and the downstream effector targets. Here, we will introduce the major members of each GTPase subfamily and discuss recent advances in the design and application of fluorescent resonance energy transfer-based probes, which are at the forefront of the technologies available to directly probe the differential, spatiotemporal activation dynamics of these proteins in live single cells. Currently, it is possible to specifically detect the activation status of RhoA vs. RhoC isoforms, as well as Cdc42 vs. TC-10 isoforms in living cells. Clearly, additional efforts are still required to produce biosensor systems capable of detecting other isoforms of Rho GTPases including RhoB, Rac2/3, RhoG, etc. Through such efforts, we will uncover the isoform-specific roles of these near-identical proteins in living cells, clearly an important area of the Rho GTPase biology that is not yet fully appreciated.
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Affiliation(s)
- Sara K Donnelly
- a Department of Anatomy and Structural Biology ; Albert Einstein College of Medicine of Yeshiva University ; Bronx , NY USA
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38
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de Curtis I. Roles of Rac1 and Rac3 GTPases during the development of cortical and hippocampal GABAergic interneurons. Front Cell Neurosci 2014; 8:307. [PMID: 25309333 PMCID: PMC4174739 DOI: 10.3389/fncel.2014.00307] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 09/10/2014] [Indexed: 11/25/2022] Open
Abstract
Rac GTPases are regulators of the cytoskeleton that play an important role in several aspects of neuronal and brain development. Two distinct Rac GTPases are expressed in the developing nervous system, the widely expressed Rac1 and the neural-specific Rac3 proteins. Recent experimental evidence supports a central role of these two Rac proteins in the development of inhibitory GABAergic interneurons, important modulatory elements of the brain circuitry. The combined inactivation of the genes for the two Rac proteins has profound effects on distinct aspects of interneuron development, and has highlighted a synergistic contribution of the two proteins to the postmitotic maturation of specific populations of cortical and hippocampal interneurons. Rac function is modulated by different types of regulators, and can influence the activity of specific effectors. Some of these proteins have been associated to the development and maturation of interneurons. Cortical interneuron dysfunction is implicated in several neurological and psychiatric diseases characterized by cognitive impairment. Therefore the description of the cellular processes regulated by the Rac GTPases, and the identification of the molecular networks underlying these processes during interneuron development is relevant to the understanding of the role of GABAergic interneurons in cognitive functions.
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Affiliation(s)
- Ivan de Curtis
- Cell Adhesion Unit, Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute San Raffaele University Milano, Italy
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39
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Tivodar S, Kalemaki K, Kounoupa Z, Vidaki M, Theodorakis K, Denaxa M, Kessaris N, de Curtis I, Pachnis V, Karagogeos D. Rac-GTPases Regulate Microtubule Stability and Axon Growth of Cortical GABAergic Interneurons. Cereb Cortex 2014; 25:2370-82. [PMID: 24626607 PMCID: PMC4537417 DOI: 10.1093/cercor/bhu037] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Cortical interneurons are characterized by extraordinary functional and morphological diversity. Although tremendous progress has been made in uncovering molecular and cellular mechanisms implicated in interneuron generation and function, several questions still remain open. Rho-GTPases have been implicated as intracellular mediators of numerous developmental processes such as cytoskeleton organization, vesicle trafficking, transcription, cell cycle progression, and apoptosis. Specifically in cortical interneurons, we have recently shown a cell-autonomous and stage-specific requirement for Rac1 activity within proliferating interneuron precursors. Conditional ablation of Rac1 in the medial ganglionic eminence leads to a 50% reduction of GABAergic interneurons in the postnatal cortex. Here we examine the additional role of Rac3 by analyzing Rac1/Rac3 double-mutant mice. We show that in the absence of both Rac proteins, the embryonic migration of medial ganglionic eminence-derived interneurons is further impaired. Postnatally, double-mutant mice display a dramatic loss of cortical interneurons. In addition, Rac1/Rac3-deficient interneurons show gross cytoskeletal defects in vitro, with the length of their leading processes significantly reduced and a clear multipolar morphology. We propose that in the absence of Rac1/Rac3, cortical interneurons fail to migrate tangentially towards the pallium due to defects in actin and microtubule cytoskeletal dynamics.
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Affiliation(s)
- Simona Tivodar
- Institute of Molecular Biology and Biotechnology (IMBB, FORTH), Heraklion, Greece Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece
| | - Katerina Kalemaki
- Institute of Molecular Biology and Biotechnology (IMBB, FORTH), Heraklion, Greece Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece
| | - Zouzana Kounoupa
- Institute of Molecular Biology and Biotechnology (IMBB, FORTH), Heraklion, Greece Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece
| | - Marina Vidaki
- Institute of Molecular Biology and Biotechnology (IMBB, FORTH), Heraklion, Greece Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece Current Address: Koch Institute for Integrative Cancer Research at MIT, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kostas Theodorakis
- Institute of Molecular Biology and Biotechnology (IMBB, FORTH), Heraklion, Greece Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece
| | - Myrto Denaxa
- Division of Molecular Neurobiology, Medical Research Council, National Institute for Medical Research, London, UK
| | - Nicoletta Kessaris
- Wolfson Institute for Biomedical Research and Department of Cell and Developmental Biology, University College London, UK
| | - Ivan de Curtis
- Cell Adhesion Unit, Dibit, San Raffaele Scientific Institute, 20132 Milano, Italy
| | - Vassilis Pachnis
- Division of Molecular Neurobiology, Medical Research Council, National Institute for Medical Research, London, UK
| | - Domna Karagogeos
- Institute of Molecular Biology and Biotechnology (IMBB, FORTH), Heraklion, Greece Department of Basic Science, Faculty of Medicine, University of Crete, Heraklion, Greece
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40
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Vadodaria KC, Jessberger S. Maturation and integration of adult born hippocampal neurons: signal convergence onto small Rho GTPases. Front Synaptic Neurosci 2013; 5:4. [PMID: 23986696 PMCID: PMC3752586 DOI: 10.3389/fnsyn.2013.00004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 07/29/2013] [Indexed: 01/28/2023] Open
Abstract
Adult neurogenesis, restricted to specific regions in the mammalian brain, represents one of the most interesting forms of plasticity in the mature nervous system. Adult-born hippocampal neurons play important roles in certain forms of learning and memory, and altered hippocampal neurogenesis has been associated with a number of neuropsychiatric diseases such as major depression and epilepsy. Newborn neurons go through distinct developmental steps, from a dividing neurogenic precursor to a synaptically integrated mature neuron. Previous studies have uncovered several molecular signaling pathways involved in distinct steps of this maturational process. In this context, the small Rho GTPases, Cdc42, Rac1, and RhoA have recently been shown to regulate the morphological and synaptic maturation of adult-born dentate granule cells in vivo. Distinct upstream regulators, including growth factors that modulate maturation and integration of newborn neurons have been shown to also recruit the small Rho GTPases. Here we review recent findings and highlight the possibility that small Rho GTPases may act as central assimilators, downstream of critical input onto adult-born hippocampal neurons contributing to their maturation and integration into the existing dentate gyrus (DG) circuitry.
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Affiliation(s)
- Krishna C Vadodaria
- Brain Research Institute, University of Zurich Zurich, Switzerland ; Neuroscience Center Zurich, University of Zurich and ETH Zurich Zurich, Switzerland
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Zeidán-Chuliá F, Rybarczyk-Filho JL, Salmina AB, de Oliveira BHN, Noda M, Moreira JCF. Exploring the Multifactorial Nature of Autism Through Computational Systems Biology: Calcium and the Rho GTPase RAC1 Under the Spotlight. Neuromolecular Med 2013; 15:364-83. [DOI: 10.1007/s12017-013-8224-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 02/16/2013] [Indexed: 01/08/2023]
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