scholarly journals The atypical Rho GTPase Rnd2 is critical for dentate granule neuron development and anxiety-like behavior during adult but not neonatal neurogenesis

2020 ◽  
Author(s):  
Thomas Kerloch ◽  
Fanny Farrugia ◽  
Marlène Maître ◽  
Geoffrey Terral ◽  
Muriel Koehl ◽  
...  
Keyword(s):  
Rho Gtpases ◽  
Neuronal Development ◽  
Rho Gtpase ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Granule Neurons ◽  
Loss Of Function ◽  
Neuron Development ◽  
Functional Maturation

ABSTRACTDespite the central role of Rho GTPases in neuronal development, their functions in adult hippocampal neurogenesis remain poorly explored. Here, by using a retrovirus-based loss-of-function approach in vivo, we show that the atypical Rho GTPase Rnd2 is crucial for the survival, positioning, somatodendritic morphogenesis and functional maturation of adult-born dentate granule neurons. Interestingly, most of these functions are specific to granule neurons generated during adulthood since the deletion of Rnd2 in neonatally-born granule neurons only affects dendritogenesis. In addition, suppression of Rnd2 in adult-born dentate granule neurons increases anxiety-like behaviour whereas its deletion in pups has no such effect, a finding supporting the adult neurogenesis hypothesis of anxiety disorders. Thus, our results provide mechanistic insight into the differential regulation of hippocampal neurogenesis during development and adulthood, and establishes a causal relationship between Rnd2 expression and anxiety.

scholarly journals The atypical Rho GTPase Rnd2 is critical for dentate granule neuron development and anxiety-like behavior during adult but not neonatal neurogenesis

2021 ◽  
Author(s):  
Thomas Kerloch ◽  
Fanny Farrugia ◽  
Lou Bouit ◽  
Marlène Maître ◽  
Geoffrey Terral ◽  
...  
Keyword(s):  
Adult Neurogenesis ◽  
Rho Gtpases ◽  
Neuronal Development ◽  
Rho Gtpase ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Granule Neurons ◽  
Loss Of Function ◽  
Neuron Development

AbstractDespite the central role of Rho GTPases in neuronal development, their functions in adult hippocampal neurogenesis remain poorly explored. Here, by using a retrovirus-based loss-of-function approach in vivo, we show that the atypical Rho GTPase Rnd2 is crucial for survival, positioning, somatodendritic morphogenesis, and functional maturation of adult-born dentate granule neurons. Interestingly, most of these functions are specific to granule neurons generated during adulthood since the deletion of Rnd2 in neonatally-born granule neurons only affects dendritogenesis. In addition, suppression of Rnd2 in adult-born dentate granule neurons increases anxiety-like behavior whereas its deletion in pups has no such effect, a finding supporting the adult neurogenesis hypothesis of anxiety disorders. Thus, our results are in line with the view that adult neurogenesis is not a simple continuation of earlier processes from development, and establish a causal relationship between Rnd2 expression and anxiety.

scholarly journals Brain-specific Crmp2 deletion leads to neuronal development deficits and behavioural impairments in mice

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Hongsheng Zhang ◽  
Eunchai Kang ◽  
Yaqing Wang ◽  
Chaojuan Yang ◽  
Hui Yu ◽  
...  
Keyword(s):  
Neuronal Development ◽  
Synapse Formation ◽  
Critical Role ◽  
Memory Loss ◽  
Long Term Potentiation ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Mammalian Brain ◽  
Neural Function

AbstractSeveral genome- and proteome-wide studies have associated transcription and translation changes ofCRMP2(collapsing response mediator protein 2) with psychiatric disorders, yet little is known about its function in the developing or adult mammalian brainin vivo. Here we show that brain-specificCrmp2knockout (cKO) mice display molecular, cellular, structural and behavioural deficits, many of which are reminiscent of neural features and symptoms associated with schizophrenia. cKO mice exhibit enlarged ventricles and impaired social behaviour, locomotor activity, and learning and memory. Loss ofCrmp2in the hippocampus leads to reduced long-term potentiation, abnormal NMDA receptor composition, aberrant dendrite development and defective synapse formation in CA1 neurons. Furthermore, knockdown ofcrmp2specifically in newborn neurons results in stage-dependent defects in their development during adult hippocampal neurogenesis. Our findings reveal a critical role for CRMP2 in neuronal plasticity, neural function and behavioural modulation in mice.

Metabolic Regulation of Hippocampal Neuronal Development and Its Inhibition After Irradiation

2021 ◽  
Vol 80 (5) ◽  
pp. 467-475
Author(s):  
Yu-Qing Li ◽  
C Shun Wong
Keyword(s):  
Cell Fate ◽  
Metabolic Regulation ◽  
Energy Homeostasis ◽  
Neuronal Development ◽  
Adenosine Monophosphate ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Wild Type ◽  
Newborn Neuron ◽  
Negative Effect

Abstract 5′-Adenosine monophosphate-activated protein kinase (AMPK), a key regulator of cellular energy homeostasis, plays a role in cell fate determination. Whether AMPK regulates hippocampal neuronal development remains unclear. Hippocampal neurogenesis is abrogated after DNA damage. Here, we asked whether AMPK regulates adult hippocampal neurogenesis and its inhibition following irradiation. Adult Cre-lox mice deficient in AMPK in brain, and wild-type mice were used in a birth-dating study using bromodeoxyuridine to evaluate hippocampal neurogenesis. There was no evidence of AMPK or phospho-AMPK immunoreactivity in hippocampus. Increase in p-AMPK but not AMPK expression was observed in granule neurons and subgranular neuroprogenitor cells (NPCs) in the dentate gyrus within 24 hours and persisted up to 9 weeks after irradiation. AMPK deficiency in Cre-lox mice did not alter neuroblast and newborn neuron numbers but resulted in decreased newborn and proliferating NPCs. Inhibition of neurogenesis was observed after irradiation regardless of genotypes. In Cre-lox mice, there was further loss of newborn early NPCs and neuroblasts but not newborn neurons after irradiation compared with wild-type mice. These results are consistent with differential negative effect of AMPK on hippocampal neuronal development and its inhibition after irradiation.

scholarly journals Rgs4 is a regulator of mTOR activity required for motoneuron axon outgrowth and neuronal development in zebrafish

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aya Mikdache ◽  
Marie-José Boueid ◽  
Lorijn van der Spek ◽  
Emilie Lesport ◽  
Brigitte Delespierre ◽  
...  
Keyword(s):  
Nervous System ◽  
G Protein ◽  
Neural Development ◽  
Neuronal Development ◽  
Axon Outgrowth ◽  
Rgs Proteins ◽  
Protein Signaling ◽  
Loss Of Function ◽  
G Protein Coupled

AbstractThe Regulator of G protein signaling 4 (Rgs4) is a member of the RGS proteins superfamily that modulates the activity of G-protein coupled receptors. It is mainly expressed in the nervous system and is linked to several neuronal signaling pathways; however, its role in neural development in vivo remains inconclusive. Here, we generated and characterized a rgs4 loss of function model (MZrgs4) in zebrafish. MZrgs4 embryos showed motility defects and presented reduced head and eye sizes, reflecting defective motoneurons axon outgrowth and a significant decrease in the number of neurons in the central and peripheral nervous system. Forcing the expression of Rgs4 specifically within motoneurons rescued their early defective outgrowth in MZrgs4 embryos, indicating an autonomous role for Rgs4 in motoneurons. We also analyzed the role of Akt, Erk and mechanistic target of rapamycin (mTOR) signaling cascades and showed a requirement for these pathways in motoneurons axon outgrowth and neuronal development. Drawing on pharmacological and rescue experiments in MZrgs4, we provide evidence that Rgs4 facilitates signaling mediated by Akt, Erk and mTOR in order to drive axon outgrowth in motoneurons and regulate neuronal numbers.

scholarly journals Apical polarity proteins recruit the RhoGEF Cysts to promote junctional myosin assembly

2019 ◽  
Vol 218 (10) ◽  
pp. 3397-3414 ◽  
Author(s):  
Jordan T. Silver ◽  
Frederik Wirtz-Peitz ◽  
Sérgio Simões ◽  
Milena Pellikka ◽  
Dong Yan ◽  
...  
Keyword(s):  
Rho Gtpases ◽  
Rho Gtpase ◽  
Adherens Junctions ◽  
Nucleotide Exchange ◽  
Temporal Regulation ◽  
Apical Polarity ◽  
Polarity Proteins ◽  
Spatio Temporal ◽  
Crumbs Complex

The spatio-temporal regulation of small Rho GTPases is crucial for the dynamic stability of epithelial tissues. However, how RhoGTPase activity is controlled during development remains largely unknown. To explore the regulation of Rho GTPases in vivo, we analyzed the Rho GTPase guanine nucleotide exchange factor (RhoGEF) Cysts, the Drosophila orthologue of mammalian p114RhoGEF, GEF-H1, p190RhoGEF, and AKAP-13. Loss of Cysts causes a phenotype that closely resembles the mutant phenotype of the apical polarity regulator Crumbs. This phenotype can be suppressed by the loss of basolateral polarity proteins, suggesting that Cysts is an integral component of the apical polarity protein network. We demonstrate that Cysts is recruited to the apico-lateral membrane through interactions with the Crumbs complex and Bazooka/Par3. Cysts activates Rho1 at adherens junctions and stabilizes junctional myosin. Junctional myosin depletion is similar in Cysts- and Crumbs-compromised embryos. Together, our findings indicate that Cysts is a downstream effector of the Crumbs complex and links apical polarity proteins to Rho1 and myosin activation at adherens junctions, supporting junctional integrity and epithelial polarity.

scholarly journals Red Ginseng Attenuates Aβ-Induced Mitochondrial Dysfunction and Aβ-mediated Pathology in an Animal Model of Alzheimer’s Disease

2019 ◽  
Vol 20 (12) ◽  
pp. 3030 ◽  
Author(s):  
Soo Jung Shin ◽  
Seong Gak Jeon ◽  
Jin-il Kim ◽  
Yu-on Jeong ◽  
Sujin Kim ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Hippocampal Formation ◽  
Experimental Models ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Red Ginseng ◽  
Model Of Alzheimer’S Disease

Alzheimer’s disease (AD) is the most common neurodegenerative disease and is characterized by neurodegeneration and cognitive deficits. Amyloid beta (Aβ) peptide is known to be a major cause of AD pathogenesis. However, recent studies have clarified that mitochondrial deficiency is also a mediator or trigger for AD development. Interestingly, red ginseng (RG) has been demonstrated to have beneficial effects on AD pathology. However, there is no evidence showing whether RG extract (RGE) can inhibit the mitochondrial deficit-mediated pathology in the experimental models of AD. The effects of RGE on Aβ-mediated mitochondrial deficiency were investigated in both HT22 mouse hippocampal neuronal cells and the brains of 5XFAD Aβ-overexpressing transgenic mice. To examine whether RGE can affect mitochondria-related pathology, we used immunohistostaining to study the effects of RGE on Aβ accumulation, neuroinflammation, neurodegeneration, and impaired adult hippocampal neurogenesis in hippocampal formation of 5XFAD mice. In vitro and in vivo findings indicated that RGE significantly improves Aβ-induced mitochondrial pathology. In addition, RGE significantly ameliorated AD-related pathology, such as Aβ deposition, gliosis, and neuronal loss, and deficits in adult hippocampal neurogenesis in brains with AD. Our results suggest that RGE may be a mitochondria-targeting agent for the treatment of AD.

scholarly journals α2-Chimaerin is essential for neural stem cell homeostasis in mouse adult neurogenesis

2019 ◽  
Vol 116 (27) ◽  
pp. 13651-13660 ◽  
Author(s):  
Yi-Ting Su ◽  
Shun-Fat Lau ◽  
Jacque P. K. Ip ◽  
Kit Cheung ◽  
Tom H. T. Cheung ◽  
...  
Keyword(s):  
Stem Cell ◽  
Neural Stem Cell ◽  
Rho Gtpase ◽  
Hippocampal Neurogenesis ◽  
Conditional Knockout ◽  
Adult Hippocampal Neurogenesis ◽  
Adult Neural Stem Cell ◽  
Conditional Deletion ◽  
Adult Nscs ◽  
Anxiety Depression

Adult hippocampal neurogenesis involves the lifelong generation of neurons. The process depends on the homeostasis of the production of neurons and maintenance of the adult neural stem cell (NSC) pool. Here, we report that α2-chimaerin, a Rho GTPase-activating protein, is essential for NSC homeostasis in adult hippocampal neurogenesis. Conditional deletion of α2-chimaerin in adult NSCs resulted in the premature differentiation of NSCs into intermediate progenitor cells (IPCs), which ultimately depleted the NSC pool and impaired neuron generation. Single-cell RNA sequencing and pseudotime analyses revealed that α2-chimaerin–conditional knockout (α2-CKO) mice lacked a unique NSC subpopulation, termed Klotho-expressing NSCs, during the transition of NSCs to IPCs. Furthermore, α2-CKO led to defects in hippocampal synaptic plasticity and anxiety/depression-like behaviors in mice. Our findings collectively demonstrate that α2-chimaerin plays an essential role in adult hippocampal NSC homeostasis to maintain proper brain function.

scholarly journals Postnatal NG2 proteoglycan–expressing progenitor cells are intrinsically multipotent and generate functional neurons

2003 ◽  
Vol 161 (1) ◽  
pp. 169-186 ◽  
Author(s):  
Shibeshih Belachew ◽  
Ramesh Chittajallu ◽  
Adan A. Aguirre ◽  
Xiaoqing Yuan ◽  
Martha Kirby ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Intrinsic Property ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
High Rate ◽  
Fast Kinetics ◽  
Sizeable Fraction ◽  
Ng2 Proteoglycan

Neurogenesis is known to persist in the adult mammalian central nervous system (CNS). The identity of the cells that generate new neurons in the postnatal CNS has become a crucial but elusive issue. Using a transgenic mouse, we show that NG2 proteoglycan–positive progenitor cells that express the 2′,3′-cyclic nucleotide 3′-phosphodiesterase gene display a multipotent phenotype in vitro and generate electrically excitable neurons, as well as astrocytes and oligodendrocytes. The fast kinetics and the high rate of multipotent fate of these NG2+ progenitors in vitro reflect an intrinsic property, rather than reprogramming. We demonstrate in the hippocampus in vivo that a sizeable fraction of postnatal NG2+ progenitor cells are proliferative precursors whose progeny appears to differentiate into GABAergic neurons capable of propagating action potentials and displaying functional synaptic inputs. These data show that at least a subpopulation of postnatal NG2-expressing cells are CNS multipotent precursors that may underlie adult hippocampal neurogenesis.

Loss of Rho-GDIα sensitizes podocytes to lipopolysaccharide-mediated injury

2015 ◽  
Vol 308 (11) ◽  
pp. F1207-F1216 ◽  
Author(s):  
Richard Robins ◽  
Cindy Baldwin ◽  
Lamine Aoudjit ◽  
Indra R. Gupta ◽  
Tomoko Takano
Keyword(s):  
Nephrotic Syndrome ◽  
Rho Gtpases ◽  
Rho Gtpase ◽  
Cathepsin L ◽  
Loss Of Function ◽  
Filtration Barrier ◽  
Guanine Nucleotide Dissociation Inhibitor ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Lps Treatment

Nephrotic syndrome is a disease of glomerular permselectivity that can arise as a consequence of heritable or acquired changes to the integrity of the glomerular filtration barrier. We recently reported two siblings with heritable nephrotic syndrome caused by a loss of function mutation in the gene ARHGDIA, which encodes for Rho guanine nucleotide dissociation inhibitor-α (GDIα). GDIs are known to negatively regulate Rho-GTPase signaling. We hypothesized that loss of GDIα sensitizes podocytes to external injury via hyperactivation of Rho-GTPases and p38 MAPK. We examined the response of cultured podocytes with and without knockdown of GDIα to LPS injury by assessing the levels of phospho-p38 as well as the degree of synaptopodin loss. GDIα knockdown podocytes showed more pronounced and sustained p38 phosphorylation in response to LPS compared with control podocytes, and this was blunted significantly by the Rac1 inhibitor. In LPS-treated control podocytes, synaptopodin degradation occurred, and this was dependent on p38, the proteasome, and cathepsin L. In GDIα knockdown podocytes, the same events were triggered, but the levels of synaptopodin after LPS treatment were significantly lower than in control podocytes. These experiments reveal a common pathway by which heritable and environmental risk factors converge to injure podocytes, from Rac1 hyperactivation to p38 phosphorylation and synaptopodin degradation via the ubiquitin-proteasome pathway and cathepsin L.

scholarly journals Title: In vivo phosphatidylserine variations steer Rho GTPase signaling in a cell-context dependent manner

2018 ◽  
Author(s):  
Matthieu Pierre Platre ◽  
Vincent Bayle ◽  
Laia Armengot ◽  
Joseph Bareille ◽  
Maria Mar Marques-Bueno ◽  
...  
Keyword(s):  
Single Molecule ◽  
Rho Gtpases ◽  
Rho Gtpase ◽  
Plant Root ◽  
Super Resolution ◽  
Small Gtpase ◽  
Auxin Signaling ◽  
Dependent Manner ◽  
Downstream Signaling

AbstractRho GTPases are master regulators of cell signaling, but how they are regulated depending on the cellular context is unclear. Here, we show that the phospholipid phosphatidylserine acts as a developmentally-controlled lipid rheostat that tunes Rho GTPase signaling in Arabidopsis. Live super-resolution single molecule imaging revealed that RHO-OF-PLANT6 (ROP6) is stabilized by phosphatidylserine into plasma membrane (PM) nanodomains, which is required for auxin signaling. Furthermore, we uncovered that the PM phosphatidylserine content varies during plant root development and that the level of phosphatidylserine modulates the quantity of ROP6 nanoclusters induced by auxin and hence downstream signaling, including regulation of endocytosis and gravitropism. Our work reveals that variations in phosphatidylserine levels are a physiological process that may be leveraged to regulate small GTPase signaling during development.One Sentence SummaryPhosphatidylserine acts as a developmentally-controlled lipid rheostat that regulates cellular auxin sensitivity and plant development.

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