Investigating tonic Wnt signaling throughout the adult CNS and in the hippocampal neurogenic niche of BatGal and ins-TopGal mice

Analysis of β-Catenin Signalling Activity Suggests Differential Regulation of Ontogenetically Distinct Dentate Granule Neuron Populations

In mammals, the dentate gyrus of the hippocampus is one of the few regions where neurogenesis continues throughout life. As a result, the dentate gyrus harbours neurons of ontogenetically different origin. Notably, ontogenetically different dentate granule neurons (DGNs) are morphologically distinct and fulfil specialized functions in hippocampal information processing and plasticity. Development of adult-born DGNs is tightly controlled by signals released by the complex cellular environment of the adult dentate gyrus. In mice, an adult-like cytoarchitecture of the dentate gyrus is observed only after postnatal Week 2. The question therefore arises when the signalling environment controlling adult neurogenesis is established and whether development of ontogenetically distinct DGNs is subject to the same regulatory pathways. Here, we analyse BATGAL reporter mice to determine the temporal development of β-catenin-signalling activity in the murine DGN lineage. We show that the β-catenin-signalling pattern, which is essential for precise dendritogenesis and neuronal maturation in adulthood, emerges only around 2 weeks after birth and continues to be refined over the next weeks. These results indicate that the signalling environment controlling adult neurogenesis is only gradually established and suggest that the development of ontogenetically distinct DGNs is controlled by different mechanisms.

RSPO/LGR signaling regulates proliferation of adult hippocampal neural stem cells

In the dentate gyrus of the adult hippocampus, neurogenesis from neural stem cells (NSCs) is regulated by Wnt signals from the local microenvironment. The Wnt/β-catenin pathway is active in NSCs, where it regulates proliferation and fate commitment, and subsequently its activity is strongly attenuated. The mechanisms controlling Wnt activity are poorly understood. In stem cells from adult peripheral tissues, secreted R-spondin proteins (RSPO1-4) interact with LGR4-6 receptors and control Wnt signaling strength. Here, we found that RSPO1-3 and LGR4-6 are expressed in the adult dentate gyrus and in cultured NSCs isolated from the adult mouse hippocampus. LGR4-5 expression decreased in cultured NSCs upon differentiation, concomitantly with the reported decrease in Wnt activity. Treatment with RSPO1-3 increased NSC proliferation and the expression of Cyclin D1 but did not induce the expression of Axin2 or RNF43, 2 well-described Wnt target genes. However, RSPOs enhanced the effect of Wnt3a on Axin2 and RNF43 expression as well as on Wnt/β-catenin reporter activity, indicating that they can potentiate Wnt activity in NSCs. Moreover, RSPO1-3 was found to be expressed by cultured dentate gyrus astrocytes, a crucial component of the neurogenic niche. In co-culture experiments, the astrocyte-induced proliferation of NSCs was prevented by RSPO2 knockdown in astrocytes and LGR5 knockdown in hippocampal NSCs. Additionally, RSPO2 knockdown in the adult mouse dentate gyrus reduced proliferation of neural stem and progenitor cells in vivo. Altogether, our results indicate that RSPO/LGR signaling is present in the dentate gyrus and plays a crucial role in regulating neural precursor cell proliferation.

Cerebellar granular neuron progenitors exit their germinative niche via BarH-like1 activity mediated partly by inhibition of T-cell factor

Cerebellar granule neuron progenitors (GNPs) originate from the upper rhombic lip (URL), a germinative niche in which developmental defects produce human diseases. T-cell factor (TCF) responsiveness and Notch dependence are hallmarks of self-renewal in neural stem cells. TCF activity, together with transcripts encoding proneural gene repressors hairy and enhancer of split (Hes/Hey), are detected in the URL; however, their functions and regulatory modes are undeciphered. Here, we established amphibian as a pertinent model for studying vertebrate URL development. The amphibian long-lived URL is TCF active, whereas the external granular layer (EGL) is non-proliferative and expresses hes4 and hes5 genes. Using functional and transcriptomic approaches, we show that TCF activity is necessary for URL emergence and maintenance. We establish that the transcription factor Barhl1 controls GNP exit from the URL, acting partly through direct TCF inhibition. Identification of Barhl1 target genes suggests that, besides TCF, Barhl1 inhibits transcription of hes5 genes independently of Notch signaling. Observations in amniotes suggest a conserved role for Barhl in maintenance of the URL and/or EGL via co-regulation of TCF, Hes and Hey genes.

The multifaceted role of Wnt canonical signalling in neurogenesis, neuroinflammation, and hyperexcitability in mesial temporal lobe epilepsy

Epilepsy is a neurological disorder characterised by unprovoked, repetitive seizures caused by abnormal neuronal firing. The Wnt/β-Catenin signalling pathway is involved in seizure-induced neurogenesis, aberrant neurogenesis, neuroinflammation, and hyperexcitability associated with epileptic disorder. Wnt/β-Catenin signalling is crucial for early brain development processes including neuronal patterning, synapse formation, and N-methyl-d-aspartate receptor (NMDAR) regulation. Disruption of molecular networks such as Wnt/β-catenin signalling in epilepsy could offer encouraging anti-epileptogenic targets. So, with a better understanding of the canonical Wnt/-Catenin pathway, we highlight in this review the important elements of Wnt/-Catenin signalling specifically in Mesial Temporal Lobe Epilepsy (MTLE) for potential therapeutic targets.

Therapeutic Potential of Natural Compounds from Herbs and Nutraceuticals in Alleviating Neurological Disorders: Targeting the Wnt Signaling Pathway

As an important signaling pathway in multicellular eukaryotes, the Wnt signaling pathway participates in a variety of physiological processes. Recent studies have confirmed that the Wnt signaling pathway plays an important role in neurological disorders such as stroke, Alzheimer's disease, and Parkinson's disease. The regulation of Wnt signaling by natural compounds in herbal medicines and nutraceuticals has emerged as a potential strategy for the development of new drugs for neurological disorders. Purpose: The aim of this review is to evaluate the latest research results on the efficacy of natural compounds derived from herbs and nutraceuticals in the prevention and treatment of neurological disorders by regulating the Wnt pathway in vivo and in vitro. A manual and electronic search was performed for English articles available from PubMed, Web of Science, and ScienceDirect from the January 2010 to February 2023. Keywords used for the search engines were "natural products,″ "plant derived products,″ "Wnt+ clinical trials,″ and "Wnt+,″ and/or paired with "natural products″/″plant derived products", and "neurological disorders." A total of 22 articles were enrolled in this review, and a variety of natural compounds from herbal medicine and nutritional foods have been shown to exert therapeutic effects on neurological disorders through the Wnt pathway, including curcumin, resveratrol, and querctrin, etc. These natural products possess antioxidant, anti-inflammatory, and angiogenic properties, confer neurovascular unit and blood-brain barrier integrity protection, and affect neural stem cell differentiation, synaptic formation, and neurogenesis, to play a therapeutic role in neurological disorders. In various in vivo and in vitro studies and clinical trials, these natural compounds have been shown to be safe and tolerable with few adverse effects. Natural compounds may serve a therapeutic role in neurological disorders by regulating the Wnt pathway. This summary of the research progress of natural compounds targeting the Wnt pathway may provide new insights for the treatment of neurological disorders and potential targets for the development of new drugs.

Simvastatin attenuates aluminium chloride-induced neurobehavioral impairments through activation of TGF-β1/ SMAD2 and GSK3β/β-catenin signalling pathways

Alzheimer's disease (AD) is a neurodegenerative disease characterised by the presence of β-amyloid plaques and acetylcholine depletion leading to neurobehavioral defects. AD was contributed also with downregulation of TGF-β1/SMAD2 and GSK3β/β-catenin pathways. Simvastatin (SMV) improved memory function experimentally and clinically. Hence, this study aimed to investigate the mechanistic role of SMV against aluminium chloride (AlCl3) induced neurobehavioral impairments. AD was induced by AlCl3 (50 mg/kg) for 6 weeks. Mice received Simvastatin (10 or 20 mg/kg) or Donepezil (3 mg/kg) for 6 weeks after that the histopathological, immunohistochemical and biochemical test were examined. Treatment with SMV improved the memory deterioration induced by AlCl3 with significant recovery of the histopathological changes. This was concomitant with the decrease of AChE and Aβ (1-42). SMV provides its neuroprotective effect through upregulating the protein expression of β-catenin, TGF-β1 and downregulating the expression of GSK3β, TLR4 and p-SMAD2.

Wnt signaling in the adult hippocampal neurogenic niche

The subgranular zone (SGZ) of the hippocampal dentate gyrus (DG) is a neurogenic niche of the adult brain that contains neural stem cells (NSCs) able to generate excitatory glutamatergic granule neurons, which integrate into the DG circuit and contribute to hippocampal plasticity, learning, and memory. Thus, endogenous NSCs could be harnessed for therapeutic purposes. In this context, it is critical to characterize the molecular mechanisms controlling the generation and functional integration of adult-born neurons. Adult hippocampal neurogenesis is tightly controlled by both cell-autonomous mechanisms and the interaction with the complex niche microenvironment, which harbors the NSCs and provides the signals to support their maintenance, activation, and differentiation. Among niche-derived factors, Wnt ligands play diverse roles. Wnts are secreted glycoproteins that bind to Frizzled receptors and co-receptors to trigger the Wnt signaling pathway. Here, we summarize the current knowledge about the roles of Wnts in the regulation of adult hippocampal neurogenesis. We discuss the possible contribution of the different niche cells to the regulation of local Wnt signaling activity, and how Wnts derived from different cell types could induce differential effects. Finally, we discuss how the effects of Wnt signaling on hippocampal network activity might contribute to neurogenesis regulation. Although the evidence supports relevant roles for Wnt signaling in adult hippocampal neurogenesis, defining the cellular source and the mechanisms controlling secretion and diffusion of Wnts will be crucial to further understand Wnt signaling regulation of adult NSCs, and eventually, to propose this pathway as a therapeutic target to promote neurogenesis.

T-Cell Factors as Transcriptional Inhibitors: Activities and Regulations in Vertebrate Head Development

Since its first discovery in the late 90s, Wnt canonical signaling has been demonstrated to affect a large variety of neural developmental processes, including, but not limited to, embryonic axis formation, neural proliferation, fate determination, and maintenance of neural stem cells. For decades, studies have focused on the mechanisms controlling the activity of β-catenin, the sole mediator of Wnt transcriptional response. More recently, the spotlight of research is directed towards the last cascade component, the T-cell factor (TCF)/Lymphoid-Enhancer binding Factor (LEF), and more specifically, the TCF/LEF-mediated switch from transcriptional activation to repression, which in both embryonic blastomeres and mouse embryonic stem cells pushes the balance from pluri/multipotency towards differentiation. It has been long known that Groucho/Transducin-Like Enhancer of split (Gro/TLE) is the main co-repressor partner of TCF/LEF. More recently, other TCF/LEF-interacting partners have been identified, including the pro-neural BarH-Like 2 (BARHL2), which belongs to the evolutionary highly conserved family of homeodomain-containing transcription factors. This review describes the activities and regulatory modes of TCF/LEF as transcriptional repressors, with a specific focus on the functions of Barhl2 in vertebrate brain development. Specific attention is given to the transcriptional events leading to formation of the Organizer, as well as the roles and regulations of Wnt/β-catenin pathway in growth of the caudal forebrain. We present TCF/LEF activities in both embryonic and neural stem cells and discuss how alterations of this pathway could lead to tumors.

Wnt/β-catenin signalling is dispensable for adult neural stem cell homeostasis and activation

Adult mouse hippocampal neural stem cells (NSCs) generate new neurons that integrate into existing hippocampal networks and modulate mood and memory. These NSCs are largely quiescent and are stimulated by niche signals to activate and produce neurons. Wnt/β-catenin signalling acts at different steps along the hippocampal neurogenic lineage, but whether it has a direct role in the regulation of NSCs remains unclear. Here, we used Wnt/β-catenin reporters and transcriptomic data from in vivo and in vitro models to show that adult NSCs respond to Wnt/β-catenin signalling. Wnt/β-catenin stimulation instructed the neuronal differentiation of proliferating NSCs and promoted the activation or differentiation of quiescent NSCs in a dose-dependent manner. However, deletion of β-catenin in NSCs did not affect either their activation or maintenance of their stem cell characteristics. Together, these results indicate that, although NSCs do respond to Wnt/β-catenin stimulation in a dose-dependent and state-specific manner, Wnt/β-catenin signalling is not cell-autonomously required to maintain NSC homeostasis, which reconciles some of the contradictions in the literature as to the role of Wnt/β-catenin signalling in adult hippocampal NSCs.

Summary: Wnt/β-catenin signalling stimulation promotes the exit from quiescence and differentiation of adult hippocampal neural stem cells but is dispensable for homeostatic neurogenesis in the dentate gyrus of young mice.

Role of Wnt Signaling in Adult Hippocampal Neurogenesis in Health and Disease

Neurogenesis persists during adulthood in the dentate gyrus of the hippocampus. Signals provided by the local hippocampal microenvironment support neural stem cell proliferation, differentiation, and maturation of newborn neurons into functional dentate granule cells, that integrate into the neural circuit and contribute to hippocampal function. Increasing evidence indicates that Wnt signaling regulates multiple aspects of adult hippocampal neurogenesis. Wnt ligands bind to Frizzled receptors and co-receptors to activate the canonical Wnt/β-catenin signaling pathway, or the non-canonical β-catenin-independent signaling cascades Wnt/Ca2+ and Wnt/planar cell polarity. Here, we summarize current knowledge on the roles of Wnt signaling components including ligands, receptors/co-receptors and soluble modulators in adult hippocampal neurogenesis. Also, we review the data suggesting distinctive roles for canonical and non-canonical Wnt signaling cascades in regulating different stages of neurogenesis. Finally, we discuss the evidence linking the dysfunction of Wnt signaling to the decline of neurogenesis observed in aging and Alzheimer's disease.

β-catenin signaling modulates the tempo of dendritic growth of adult-born hippocampal neurons

In adult hippocampal neurogenesis, stem/progenitor cells generate dentate granule neurons that contribute to hippocampal plasticity. The establishment of a morphologically defined dendritic arbor is central to the functional integration of adult‐born neurons. We investigated the role of canonical Wnt/β‐catenin signaling in dendritogenesis of adult‐born neurons. We show that canonical Wnt signaling follows a biphasic pattern, with high activity in stem/progenitor cells, attenuation in immature neurons, and reactivation during maturation, and demonstrate that this activity pattern is required for proper dendrite development. Increasing β‐catenin signaling in maturing neurons of young adult mice transiently accelerated dendritic growth, but eventually produced dendritic defects and excessive spine numbers. In middle‐aged mice, in which protracted dendrite and spine development were paralleled by lower canonical Wnt signaling activity, enhancement of β‐catenin signaling restored dendritic growth and spine formation to levels observed in young adult animals. Our data indicate that precise timing and strength of β‐catenin signaling are essential for the correct functional integration of adult‐born neurons and suggest Wnt/β‐catenin signaling as a pathway to ameliorate deficits in adult neurogenesis during aging.

Wnt/β-catenin signaling in brain development and mental disorders: keeping TCF7L2 in mind

Canonical Wnt signaling, which is transduced by β-catenin and lymphoid enhancer factor 1/T cell-specific transcription factors (LEF1/TCFs), regulates many aspects of metazoan development and tissue renewal. Although much evidence has associated canonical Wnt/β-catenin signaling with mood disorders, the mechanistic links are still unknown. Many components of the canonical Wnt pathway are involved in cellular processes that are unrelated to classical canonical Wnt signaling, thus further blurring the picture. The present review critically evaluates the involvement of classical Wnt/β-catenin signaling in developmental processes that putatively underlie the pathology of mental illnesses. Particular attention is given to the roles of LEF1/TCFs, which have been discussed surprisingly rarely in this context. Highlighting recent discoveries, we propose that alterations in the activity of LEF1/TCFs, and particularly of transcription factor 7-like 2 (TCF7L2), result in defects previously associated with neuropsychiatric disorders, including imbalances in neurogenesis and oligodendrogenesis, the functional disruption of thalamocortical circuitry and dysfunction of the habenula.

Frizzled-1 receptor regulates adult hippocampal neurogenesis

Background

In the adult hippocampus new neurons are continuously generated from neural stem cells (NSCs) present at the subgranular zone of the dentate gyrus. This process is controlled by Wnt signaling, which plays a complex role in regulating multiple steps of neurogenesis including maintenance, proliferation and differentiation of progenitor cells and the development of newborn neurons. Differential effects of Wnt signaling during progression of neurogenesis could be mediated by cell-type specific expression of Wnt receptors. Here we studied the potential role of Frizzled-1 (FZD1) receptor in adult hippocampal neurogenesis.

Results

In the adult dentate gyrus, we determined that FZD1 is highly expressed in NSCs, neural progenitors and immature neurons. Accordingly, FZD1 is expressed in cultured adult hippocampal progenitors isolated from mouse brain. To evaluate the role of this receptor in vivo we targeted FZD1 in newborn cells using retroviral-mediated RNA interference. FZD1 knockdown resulted in a marked decrease in the differentiation of newborn cells into neurons and increased the generation of astrocytes, suggesting a regulatory role for the receptor in cell fate commitment. In addition, FZD1 knockdown induced an extended migration of adult-born neurons within the granule cell layer. However, no differences were observed in total dendritic length and dendritic arbor complexity between control and FZD1-deficient newborn neurons.

Conclusions

Our results show that FZD1 regulates specific stages of adult hippocampal neurogenesis, being required for neuronal differentiation and positioning of newborn neurons into the granule cell layer, but not for morphological development of adult-born granule neurons.

The Wnt adaptor protein ATP6AP2 regulates multiple stages of adult hippocampal neurogenesis

In the mammalian hippocampus, canonical Wnt signals provided by the microenvironment regulate the differentiation of adult neural stem cells (NSCs) toward the neuronal lineage. Wnts are part of a complex and diverse set of signaling pathways and the role of Wnt/Planar cell polarity (PCP) signaling in adult neurogenesis remains unknown. Using in vitro assays on differentiating adult NSCs, we identified a transition of Wnt signaling responsiveness from Wnt/β-catenin to Wnt/PCP signaling. In mice, retroviral knockdown strategies against ATP6AP2, a recently discovered core protein involved in both signaling pathways, revealed that its dual role is critical for granule cell fate and morphogenesis. We were able to confirm its dual role in neurogenic Wnt signaling in vitro for both canonical Wnt signaling in proliferating adult NSCs and non-canonical Wnt signaling in differentiating neuroblasts. Although LRP6 appeared to be critical for granule cell fate determination, in vivo knockdown of PCP core proteins FZD3 and CELSR1-3 revealed severe maturational defects without changing the identity of newborn granule cells. Furthermore, we found that CELSR1-3 control distinctive aspects of PCP-mediated granule cell morphogenesis with CELSR1 regulating the direction of dendrite initiation sites and CELSR2/3 controlling radial migration and dendritic patterning. The data presented here characterize distinctive roles for Wnt/β-catenin signaling in granule cell fate determination and for Wnt/PCP signaling in controlling the morphological maturation of differentiating neuroblasts.

The Role of Wnt/β-Catenin Signaling Pathway in Disrupted Hippocampal Neurogenesis of Temporal Lobe Epilepsy: A Potential Therapeutic Target?

Temporal lobe epilepsy is one of the most common clinical neurological disorders. One of the major pathological findings in temporal lobe epilepsy is hippocampal sclerosis, characterized by massive neuronal loss and severe gliosis. The epileptogenesis process of temporal lobe epilepsy usually starts with initial precipitating insults, followed by neurodegeneration, abnormal hippocampus circuitry reorganization, and the formation of hypersynchronicity. Experimental and clinical evidence strongly suggests that dysfunctional neurogenesis is involved in the epileptogenesis. Recent data demonstrate that neurogenesis is induced by acute seizures or precipitating insults, whereas the capacity of neuronal recruitment and proliferation substantially decreases in the chronic phase of epilepsy. Participation of the Wnt/β-catenin signaling pathway in neurogenesis reveals its importance in epileptogenesis; its dysfunction contributes to the structural and functional abnormality of temporal lobe epilepsy, while rescuing this pathway exerts neuroprotective effects. Here, we summarize data supporting the involvement of Wnt/β-catenin signaling in the epileptogenesis of temporal lobe epilepsy. We also propose that the Wnt/β-catenin signaling pathway may serve as a promising therapeutic target for temporal lobe epilepsy treatment.

Wnts are expressed in the spinal cord of adult mice and are differentially induced after injury

The Wnt family of proteins plays key roles during central nervous system development and has been involved in several neuropathologies during adulthood, including spinal cord injury (SCI). However, Wnts expression knowledge is relatively limited during adult stages. Here, we sought to define the Wnt family expression pattern after SCI in adult mice by using quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC). Under physiological conditions, the messenger RNAs (mRNAs) of most Wnt ligands, inhibitors, receptors, and coreceptors are constitutively expressed in healthy adult mice. After dorsal hemisection, we found significant time-dependent variations, with a prominent up-regulation of Wnt inhibitory factor 1 (Wif1). IHC against Frizzled (Fz) 1 and Fz4, as representatives of late and acute up-regulated receptors, showed a differential expression in the uninjured spinal cord of Fz1 by neurons and oligodendrocytes and Fz4 by astrocytes. After injury, both receptors were maintained in the same type of cells. Finally, by using BATgal reporter mice, our results revealed active β-catenin signaling in neurons of the dorsal horn and cells of the central canal of uninjured spinal cords, besides a lack of additional SCI-induced activation. In conclusion, we demonstrate Wnt expression in the adult spinal cord of mice that is modulated by SCI, which differs from that previously described in rats. Further, Fz receptors are differentially expressed by neurons and glial cells, suggestive for cell-specific patterns and thus diverse physiological roles. Further studies will help toward in-depth characterization of the role of all Wnt factors and receptors described and eventually allow for the design of novel therapies.

Simvastatin promotes adult hippocampal neurogenesis by enhancing Wnt/β-catenin signaling

Statins improve recovery from traumatic brain injury and show promise in preventing Alzheimer disease. However, the mechanisms by which statins may be therapeutic for neurological conditions are not fully understood. In this study, we present the initial evidence that oral administration of simvastatin in mice enhances Wnt signaling in vivo. Concomitantly, simvastatin enhances neurogenesis in cultured adult neural progenitor cells as well as in the dentate gyrus of adult mice. Finally, we find that statins enhance Wnt signaling through regulation of isoprenoid synthesis and not through cholesterol. These findings provide direct evidence that Wnt signaling is enhanced in vivo by simvastatin and that this elevation of Wnt signaling is required for the neurogenic effects of simvastatin. Collectively, these data add to the growing body of evidence that statins may have therapeutic value for treating certain neurological disorders.

Physiological role of β-catenin/TCF signaling in neurons of the adult brain

Wnt/β-catenin pathway, the effectors of which are transcription factors of the LEF1/TCF family, is primarily associated with development. Strikingly, however, some of the genes of the pathway are schizophrenia susceptibility genes, and the proteins that are often mutated in neurodegenerative diseases have the ability to regulate β-catenin levels. If impairment of this pathway indeed leads to these pathologies, then it likely plays a physiological role in the adult brain. This review provides an overview of the current knowledge on this subject. The involvement of β-catenin and LEF1/TCF factors in adult neurogenesis, synaptic plasticity, and the function of thalamic neurons are discussed. The data are still very preliminary and often based on circumstantial or indirect evidence. Further research might help to understand the etiology of the aforementioned pathologies.

Wnt signaling regulates intermediate precursor production in the postnatal dentate gyrus by regulating CXCR4 expression

Previous studies have examined the role of diverse signaling pathways in dentate neurogenesis, but how these signaling pathways are integrated remains unknown. Using mice that allow genetic manipulation of type 1 radial progenitors in the dentate, we show that forced induction of Wnt signaling leads to expansion of the intermediate progenitor cell (IPC) pool while selective activation of Sonic hedgehog (Shh) signaling drives neurogenesis without significant expansion of IPCs. Thus, both Wnt and Shh signaling are proneurogenic, but they act in distinct manners when their signaling is forced in subgranular zone radial progenitors. We examined potential targets of the Wnt pathway in these cells and found that Cxcr4 is a direct target of Lef1 in dentate gyrus progenitors and that loss of Cxcr4 in postnatal neurogenesis decreases the production of IPCs. This suggests that Wnt activation of dentate gyrus progenitors induces Cxcl12 signaling by regulating receptor expression. This study provides evidence that distinct morphogenic pathways have notably different roles in regulating ongoing dentate neurogenesis.

Glycogen synthase kinase 3 inhibition promotes adult hippocampal neurogenesis in vitro and in vivo

Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase originally identified as a regulator of glycogen metabolism but it also plays a pivotal role in numerous cellular functions, including differentiation, cell cycle regulation, and proliferation. The dentate gyrus of the hippocampus, together with the subventricular zone of the lateral ventricles, is one of the regions in which neurogenesis takes place in the adult brain. Here, using a chemical genetic approach that involves the use of several diverse inhibitors of GSK-3 as pharmacological tools, we show that inhibition of GSK-3 induces proliferation, migration, and differentiation of neural stem cells toward a neuronal phenotype in in vitro studies. Also, we demonstrate that inhibition of GSK-3 with the small molecule NP03112, called tideglusib, induces neurogenesis in the dentate gyrus of the hippocampus of adult rats. Taken together, our results suggest that GSK-3 should be considered as a new target molecule for modulating the production and integration of new neurons in the hippocampus as a treatment for neurodegenerative diseases or brain injury and, consequently, its inhibitors may represent new potential therapeutic drugs in neuroregenerative medicine.