Monitoring of age- and gender-related alterations of endocannabinoid levels in selected brain regions with the use of SPME probes.

INTRODUCTION: The endocannabinoid system consists of different types of receptors, enzymes and endocannabinoids (ECs), which are involved in several physiological processes, but also play important role in the development and progression of central nervous system disorders. OBJECTIVES: The purpose of this study was to apply precise and sensitive methodology for monitoring of four ECs, namely anandamide (AEA), 2-arachidonoyl glycerol (2-AG), N-arachidonoyl dopamine (NADA), 2-arachidonyl glyceryl ether (2-AGe) in selected brain regions of female and male rats at different stages of development (young, adult and old). METHODS: Biocompatible solid-phase microextraction (SPME) probes were introduced into the intact (non-homogenized) brain structures for isolation of four ECs, and the extracts were subjected to LC-MS/MS analysis. Two chemometric approaches, namely hierarchical cluster analysis (HCA) and Principal Component Analysis (PCA) were applied to provide more information about the levels of 2-AG and AEA in different brain structures. RESULTS: 2-AG and AEA were extracted and could be quantified in each brain region; the level of 2-AG was significantly higher in comparison to the level of AEA. Two highly unstable ECs, NADA and 2-AGe, were captured by SPME probes from intact brain samples for the first time. CONCLUSION: SPME probes were able to isolate highly unstable endogenous compounds from intact tissue, and provided new tools for precise analysis of the level and distribution of ECs in different brain regions. Monitoring of ECs in brain samples is important not only in physiological conditions, but also may contribute to better understanding of the functioning of the endocannabinoid system in various disorders.

EBI2 is expressed in glial cells in multiple sclerosis lesions, and its knock-out modulates remyelination in the cuprizone model.

EBI2 receptor regulates the immune system, and in multiple, sclerosis is upregulated in the central nervous system infiltrating lymphocytes. In newborn EBI2-deficient mice, myelin development is delayed, and its persistent antagonism inhibits remyelination in chemically demyelinated organotypic cerebellar slices. We used the cuprizone model of multiple sclerosis to elucidate the role of central nervous system-expressed EBI2 in de- and remyelination. The wild-type and EBI2 knock-out mice were fed 0.2% cuprizone in chow for 5 weeks and allowed to recover on a normal diet for 2 weeks. The data showed less efficient recovery of myelin, attenuated oligodendrocyte loss, fewer astrocytes and increased total cholesterol levels in the EBI2 knock-out mice after recovery. Moreover, the wild-type mice upregulated EBI2 expression after recovery confirming the involvement of EBI2 signalling during recovery from demyelination in the cuprizone model. The pro-inflammatory cytokine levels were at comparable levels in the wild-type and EBI2 knock-out mice, with only minor differences in TNFα and IL1ß levels either at peak or during recovery. The neuroinflammatory signalling molecules, Abl1 kinase and NFКB1 (p105/p50) subunit, were significantly downregulated in the EBI2 knock-out mice at peak of disease. Immunohistochemical investigations of EBI2 receptor distribution in the central nervous system (CNS) cells in multiple sclerosis (MS) brain revealed strong expression of EBI2 in astrocytes and microglia inside the plaques implicating glia-expressed EBI2 in multiple sclerosis pathophysiology. Taken together, these findings demonstrate the involvement of EBI2 signalling in the recovery from demyelination rather than in demyelination and as such warrant further research into the role of EBI2 in remyelination.

EBI2 Is Temporarily Upregulated in MO3.13 Oligodendrocytes during Maturation and Regulates Remyelination in the Organotypic Cerebellar Slice Model.

The EBI2 receptor regulates the immune system and is expressed in various immune cells including B and T lymphocytes. It is also expressed in astrocytes in the central nervous system (CNS) where it regulates pro-inflammatory cytokine release, cell migration and protects from chemically induced demyelination. Its signaling and expression are implicated in various diseases including multiple sclerosis, where its expression is increased in infiltrating immune cells in the white matter lesions. Here, for the first time, the EBI2 protein in the CNS cells in the human brain was examined. The function of the receptor in MO3.13 oligodendrocytes, as well as its role in remyelination in organotypic cerebellar slices, were investigated. Human brain sections were co-stained for EBI2 receptor and various markers of CNS-specific cells and the human oligodendrocyte cell line MO3.13 was used to investigate changes in EBI2 expression and cellular migration. Organotypic cerebellar slices prepared from wild-type and cholesterol 25-hydroxylase knock-out mice were used to study remyelination following lysophosphatidylcholine (LPC)-induced demyelination. The data showed that EBI2 receptor is present in OPCs but not in myelinating oligodendrocytes in the human brain and that EBI2 expression is temporarily upregulated in maturing MO3.13 oligodendrocytes. Moreover, we show that migration of MO3.13 cells is directly regulated by EBI2 and that its signaling is necessary for remyelination in cerebellar slices post-LPC-induced demyelination. The work reported here provides new information on the expression and role of EBI2 in oligodendrocytes and myelination and provides new tools for modulation of oligodendrocyte biology and therapeutic approaches for demyelinating diseases.

Computer Modeling of Alzheimer's Disease-Simulations of Synaptic Plasticity and Memory in the CA3-CA1 Hippocampal Formation Microcircuit.

This paper aims to present computer modeling of synaptic plasticity and memory in the CA3-CA1 hippocampal formation microcircuit. The computer simulations showed a comparison of a pathological model in which Alzheimer's disease (AD) was simulated by synaptic degradation in the hippocampus and control model (healthy) of CA3-CA1 networks with modification of weights for the memory. There were statistically higher spike values of both CA1 and CA3 pyramidal cells in the control model than in the pathological model (p = 0.0042 for CA1 and p = 0.0033 for CA3). A similar outcome was achieved for frequency (p = 0.0002 for CA1 and p = 0.0001 for CA3). The entropy of pyramidal cells of the healthy CA3 network seemed to be significantly higher than that of AD (p = 0.0304). We need to study a lot of physiological parameters and their combinations of the CA3-CA1 hippocampal formation microcircuit to understand AD. High statistically correlations were obtained between memory, spikes and synaptic deletion in both CA1 and CA3 cells.

Effects of Inducing Gamma Oscillations in Hippocampal Subregions DG, CA3, and CA1 on the Potential Alleviation of Alzheimer's Disease-Related Pathology: Computer Modeling and Simulations.

The aim of this study was to evaluate the possibility of the gamma oscillation function (40-130 Hz) to reduce Alzheimer's disease related pathology in a computer model of the hippocampal network dentate gyrus, CA3, and CA1 (DG-CA3-CA1) regions. Methods: Computer simulations were made for a pathological model in which Alzheimer's disease was simulated by synaptic degradation in the hippocampus. Pathology modeling was based on sequentially turning off the connections with entorhinal cortex layer 2 (EC2) and the dentate gyrus on CA3 pyramidal neurons. Gamma induction modeling consisted of simulating the oscillation provided by the septo-hippocampal pathway with band frequencies from 40-130 Hz. Pathological models with and without gamma induction were compared with a control. Results: In the hippocampal regions of DG, CA3, and CA1, and jointly DG-CA3-CA1 and CA3-CA1, gamma induction resulted in a statistically significant improvement in terms of increased numbers of spikes, spikes per burst, and burst duration as compared with the model simulating Alzheimer's disease (AD). The positive maximal Lyapunov exponent was negative in both the control model and the one with gamma induction as opposed to the pathological model where it was positive within the DG-CA3-CA1 region. Gamma induction resulted in decreased transfer entropy in accordance with the information flow in DG → CA3 and CA3 → CA1. Conclusions: The results of simulation studies show that inducing gamma oscillations in the hippocampus may reduce Alzheimer's disease related pathology. Pathologically higher transfer entropy values after gamma induction returned to values comparable to the control model.

The cerebellum: the 'little' brain and its big role.

Reports from recent years provide compelling evidence about the structure and the existence of functional topography in the cerebellum. However, most of them focused on the motor functions of the cerebellum. Recent studies suggest the involvement of the posterior lobe of the cerebellum in the context of neurodegenerative and cognitive disorders. The pathophysiology of these diseases is not sufficiently understood, and recent studies indicate that it could also affect additional subregions of the cerebellum. Anatomical and clinical studies, combined with neuroimaging, provide new ways of thinking about the organization and functioning of the cerebellum. This review summarizes knowledge about the topography and functions of the cerebellum, and focuses on its anatomical and functional contributions to the development of neurological diseases.

Mechanoreceptor Piezo1 Is Downregulated in Multiple Sclerosis Brain and Is Involved in the Maturation and Migration of Oligodendrocytes in vitro.

Mechanical properties of the brain such as intracranial pressure or stiffness of the matrix play an important role in the brain's normal physiology and pathophysiology. The physical properties are sensed by the cells through mechanoreceptors and translated into ion currents which activate multiple biochemical cascades allowing the cells to adapt and respond to changes in their microenvironment. Piezo1 is one of the first identified mechanoreceptors. It modulates various central nervous system functions such as axonal growth or activation of astrocytes. Piezo1 signaling was also shown to play a role in the pathophysiology of Alzheimer's disease. Here, we explore the expression of the mechanoreceptor Piezo1 in human MO3.13 oligodendrocytes and human MS/non-MS patients' brains and investigate its putative effects on oligodendrocyte proliferation, maturation, and migration. We found that Piezo1 is expressed in human oligodendrocytes and oligodendrocyte progenitor cells in the human brain and that its inhibition with GsMTx4 leads to an increment in proliferation and migration of MO3.13 oligodendrocytes. Activation of Piezo1 with Yoda-1 induced opposite effects. Further, we observed that expression of Piezo1 decreased with MO3.13 maturation in vitro. Differences in expression were also observed between healthy and multiple sclerosis brains. Remarkably, the data showed significantly lower expression of Piezo1 in the white matter in multiple sclerosis brains compared to its expression in the white matter in healthy controls. There were no differences in Piezo1 expression between the white matter plaque and healthy-appearing white matter in the multiple sclerosis brain. Taken together, we here show that Piezo1-induced signaling can be used to modulate oligodendrocyte function and that it may be an important player in the pathophysiology of multiple sclerosis.

Phenylbutyrate administration reduces changes in the cerebellar Purkinje cells population in PDC­deficient mice.

In humans, pyruvate dehydrogenase complex (PDC) deficiency impairs brain energy metabolism by reducing the availability of the functional acetyl­CoA pool. This "hypometabolic defect" results in congenital lactic acidosis and abnormalities of brain morphology and function, ranging from mild ataxia to profound psychomotor retardation. Our previous study showed reduction in total cell number and dendritic arbors in the cerebellar Purkinje cells in systemic PDC­deficient mice. Phenylbutyrate has been shown to increase PDC activity in cultured fibroblasts from PDC­deficient patients. Hence, we investigated the effects of postnatal (days 2­35) phenylbutyrate administration on the cerebellar Purkinje cell population in PDC­deficient female mice. Histological analyses of different regions of cerebellar cortex from the brain­specific PDC­deficient saline­injected mice revealed statistically significant reduction in the Purkinje cell density and increased cell size of the individual Purkinje cell soma compared to control PDC­normal, saline­injected group. Administration of phenylbutyrate to control mice did not cause significant changes in the Purkinje cell density and cell size in the studied regions. In contrast, administration of phenylbutyrate variably lessened the ill effects of PDC deficiency on Purkinje cell populations in different areas of the cerebellum. Our results lend further support for the possible use of phenylbutyrate as a potential treatment for PDC deficiency.

Changes in NGF/c-Fos double staining in the structures of the limbic system in juvenile and aged rats exposed to forced swim test.

This study aimed to investigate the influence of acute (a single 15 min) and chronic (15 min daily for 21 days) exposure to forced swim (FS) test on nerve growth factor (NGF)/c-Fos cells in hypothalamic paraventricular (PV) and supraoptic (SO) nuclei, the central (CeA) and medial (MeA) amygdaloid nuclei and CA3-hippocampus in juvenile (P28) and aged (P360) rats. The double-immunofluorescence (-ir) method was used to detect NGF-ir and c-Fos-ir cells. The amount of NGF/c-Fosir cells in relation to all NGF-ir cells is shown as a percentage. In the acute FS test an increase in NGF/c-Fos-ir cells (P<.05) was observed in all studied structures of juvenile rats and in the PV and SO of the aged individuals. After chronic FS stress, the NGF/c-Fos-ir ratio remained unaltered (except in the SO) in P28, but it increased (P<.05) in all investigated regions in P360 compared with the controls. The findings may reflect the state of molecular plasticity within the limbic hypothalamicpituitary- adrenocortical (HPA) axis in both age groups, yet the phenomenon of habituation in NGF/c-Fos-ir after chronic FS exposure was observed only in juvenile animals.

Synthesis and Biological Evaluation of Acridine/Acridone Analogs as Potential Anticancer Agents.

BACKGROUND: The lack of efficacious therapy for advanced melanoma and neuroblastoma makes new approaches necessary. Therefore, many scientists seek new, more effective, more selective and less toxic anticancer drugs. OBJECTIVE: We propose the synthesis of the new functionalized analogs of 1-nitroacridine/4- nitroacridone connected to tuftsin/retro-tuftsin derivatives as potential anticancer agents. METHODS: Acridine and acridone analogues were prepared by Ullmann condensation and then cyclization reaction. As a result of nucleophilic substitution reaction 1-nitro-9-phenoxyacridine or 1- chloro-4-nitro-9(10H)-acridone with the corresponding peptides, the planned acridine derivatives (10a-c, 12, 17-a-d, 19) have been obtained. The cytotoxic activity of the newly obtained analogs were evaluated against melanotic (Ma) and amelanotic (Ab) melanoma cell lines and neuroblastoma SH-SY5Y by using the XTT method. Apoptosis and cell cycle were analyzed by flow cytometry. RESULTS: Among the investigated analogs compound 12 exhibited the highest potency comparable to dacarbazine action for amelanotic Ab melanoma cells. FLICA test (flurochrome-labeled inhibitors of caspases) showed that this analog significantly increased the content of cells with activated caspases (C+) among both neuroblastoma lines and only Ab melanoma line. Using phosphatidylserine (PS) externalization assay, 12 induced changes in the Ab melanoma plasma membrane structure as the externalization of phosphatidylserine (An+ cells). These changes in neuroblastoma cells were less pronounced. CONCLUSION: Analog 12 could be proposed as the new potential chemotherapeutic against amelanotic melanoma form especially.

The anatomical relationships between the serotonergic afferents and the neurons containing calcium-binding proteins in the rat claustrum.

Claustrum is a telencephalic structure integrating information of various modalities. Proper functioning of this structure depends on the presence of a network of intrinsic connections. This includes GABA-ergic neuronal populations that also contain calcium-binding proteins (CaBPs). The goal of this study was to analyze qualitative and quantitative the 5-HT-containing fibers in the rat claustrum and to assess the relationships between these fibers and the populations of claustral neurons expressing CaBPs. We used the methods of immunocytochemistry and morphometry. The serotonergic fibers in the claustrum are heterogeneous, both with respect to their morphology and spatial distribution. Thin varicose fibers are more numerous and are homogeneously distributed within the claustrum. Remaining fibers were thicker and possessed larger varicosities. They were present mainly in the ventral part of the claustrum. Although the serotonergic fibers are found in the vicinity of claustral cells containing CaBPs, direct contacts between these fibers and cells are rare. Other mechanisms, including volume transmission, may possibly mediate serotonergic influences.

Analysis of calretinin immunoreactivity in the rat piriform cortex after open field stress during postnatal maturation.

In our study we used c-Fos protein to identify whether cells containing calretinin (CR) in the rat piriform cortex are engaged in the response to stress stimulation and to find out how this expression changes during maturation (PC). The material consisted of Wistar strain rats of between 0 and 120 days of age divided into 9 groups. Each group consisted of 5 experimental and 3 control rats. Animals from the experimental groups were exposed to the open field test throughout 10 minutes. The control animals were kept in a home cage. In all age-related control rats weak c-Fos immunoreactivity was observed. Our results showed that cells containing c-Fos following an acute open field test were observed predominantly in layers II and III of the PC just after birth. Their number then increased and stabilised on P30. We had already observed immature CR-ir cells at birth. In the 4th week of life these neurons achieved maturity. Their number increased to P90 and decreased in older animals. CR-ir neurons were localised mainly in layer II and to a lesser degree in layers III and I of the PC. Double immunostaining c-Fos/CR revealed that the level of co-localisation was low. Only small differences were observed between the anterior and posterior parts of the PC. In the anterior part a higher number of CR-ir neurons was found. The difference in the level of co-localisation between the anterior and posterior parts was age-related and differentiated. Our results may suggest that during maturation CR-ir neurons of the piriform cortex are not the main population engaged in response to the open field test.

Chronic electric stimulation of the midbrain ventral tegmental area increases spleen but not blood natural killer cell cytotoxicity in rats.

Previously we found that in conscious, freely behaving rats chronic electric stimulation of the lateral hypothalamus (LH) caused significant augmentation of natural killer cell cytotoxicity (NKCC) and a large granular lymphocyte (LGL) number more pronounced in the spleen than in the peripheral blood. The LH belongs to the so-called "brain reward system", a collection of the central structures whose activation produce positive emotions. The midbrain ventral tegmental area (VTA) is another prominent reward-relevant structure. In the present work, chronic electric stimulation of VTA (constant current 0.1 ms duration cathodal pulses delivered at frequency 50 Hz during 60 min daily session for 14 consecutive days) caused in rats an increase in the spleen but not in the peripheral blood NKCC (chromium release assay) without simultaneous effect on the number of large granular lymphocytes (LGL) (morphological method) and plasma level of prolactin (PRL), growth hormone (GH), corticosterone (COR), and testosterone (TST). This effect was anatomically specific as no influence of analogous thalamic stimulation on immune and endocrine response was found. The results obtained indicate that both reward-related areas VTA and LH enhance the cell-mediated immune response, represented by natural killer cytotoxicity, especially in the spleen. However, the effect pronounced by VTA is weaker than that of LH, possibly due to additional connections of LH with the hormonal and/or autonomic control systems.

Parvalbumin containing neurons of the piriform cortex in open field stress -- a developmental study in the rat.

In our study we used c-Fos protein (as a marker of cellular activity) to identify whether cells containing parvalbumin (PV) in the piriform cortex (PC) are engaged in the response to stress stimulation and to discover how this expression changes during maturation. The material consisted of Wistar rats of postnatal (P) ages between 0 and 120 days divided into 9 groups: P0, P4, P7, P10, P14, P21, P30, P90, P120. Each group consisted of 5 experimental and 3 control animals. Rats of the experimental groups were exposed to the "open field test" throughout 10 minutes. The control animals were kept in a home cage. Our results showed that c-Fos activity in the open field test was observed in layers II and III of PC after birth. It then increased and stabilised on P30. In the second week of life PV-positive cells were also observed in those layers. These achieved maturity in the 4th week of life. After this time basket-like structures appeared but the level of PV/c-Fos co-localisation was low. Only small differences were observed between the anterior and posterior parts of PC. In the anterior part a higher number of PV-positive neurons, neuropil threads, and basket-like structures and a larger degree of PV/c-Fos co-localisation were observed. Our results suggested that during maturation PV cells are not directly activated in response to stress stimuli but PV neurons via their numerous endings influence the activation of c-Fos-positive cells predominantly in the anterior part of PC.

Cholinergic innervation of parvalbumin- and calbindin-containing neurones in the hippocampus during postnatal development of the rat brain.

Immunohistochemical study of the cholinergic innervation of the parvalbumin- and calbindin-containing cells in the hippocampus was conducted on 30 rat brains of various postnatal ages: P0, P4, P7, P14, P21, P30, P60 and P180. Sections with double immunostaining for vesicular acetylcholine transporter (VAChT; the marker of cholinergic cells, fibres and terminals) and parvalbumin (PV) or calbindin (CB) were analysed using confocal laser-scanning microscope. Obtained data demonstrate that the pattern of cholinergic innervation of calbindin- and parvalbumin-immunoreactive hippocampal neurones shows some differences. During development as well as in the adult species cholinergic terminals preferentially innervate CB-containing neurones, while cholinergic terminals on PV-containing cells were observed rarely. Cholinergic endings on the CB-ir neurones are localised both on their somata and dendrites, whereas on PV-ir cells they form synaptic contact predominantly with processes. In spite of the unquestionable cholinergic influence particularly on CB-ir cells, the number of cholinergic endings suggests that this input seems not to be crucial for the activity of the studied cell populations.

The influence of open field exposure on neurons containing nitric oxide synthase in the basolateral complex and paracapsular intercalated nerve cells of the rat amygdala.

Our intention in the present study was to ascertain whether NO-producing cells in the basolateral complex (BLC) and paracapsular intercalated nerve cell groups (Ip) of the amygdala are activated in the open field (OF) test. The material consisted of 8 adult rat brains. The OF test was applied throughout 10 min and 90 min before the death of the animals. The brain sections were double stained using the antibodies against c-Fos (marker of neuronal activation) and against nitric oxide synthase (NOS -- marker of NO-producing cells). The neurons containing NOS and those revealing c-Fos activity constituted distinct populations within both the BLC and Ip but NOS-immunoreactive fibres often surrounded the c-Fos-immunoreactive neurons. Our results suggest that (1) neurons of the basolateral complex of the amygdala and paracapsular intercalated islands are involved but probably not crucial for the open field stress response and (2) NOS-immunoreactive cells in the BLC and Ip are not activated after OF exposure.

Correlation between dopaminergic phenotype and expression of calretinin in the midbrain nuclei of the opossum (Monodelphis domestica): an immunohistological study.

We investigated distribution and morphology of neurons of the midbrain nuclei: the ventral tegmental area (VTA), substantia nigra (SN) and periaqueductal gray (PAG) of the adult grey short-tailed opossums that were double immunolabeled for the presence of calretinin (CR) and/or tyrosine hydroxylase (TH). The majority of TH-immunopositive neurons and fibers were located in the VTA, SN, and only scarce population of small neurons expressing TH was present in the PAG. In the SN 80 percent of TH-expressing neurons had large cell bodies, and only a small fraction had small perikarya. In the PAG populations of large and medium sized neurons were equal and 20 percent of neurons had small perikarya. Much scarcer population of TH-immunoreactive neurons in the PAG consisted of large or small neurons in its dorsal part (PAGd) and almost exclusively small neurons in the ventral part (PAGv). Distribution of neurons expressing TH and their types in the opossum are similar to those in rodents. The majority of CR-immunolabeled neurons were found in the VTA. In its subdivision, the parabrachal pigmented nucleus (PBP) cells expressing CR were approximately 28 percent more numerous than cells expressing TH. In spite of that, only 42 percent of TH-expressing neurons coexpressed CR. The high degree of colocalization TH and CR was observed in the SN. We propose that a higher percentage of TH/CR colocalization, which is observed in the opossums SN, may give them the ability to adapt to changes in their motor functions.

Transcription factor Pax6 is expressed by astroglia after transient brain ischemia in the rat model.

Reactive astrogliosis is regarded as an universal astrocytic response to different kinds of lesions, concerned with glial fibrillary acidic protein (GFAP) up-regulation, cellular hypertrophy and proliferation. The origin of reactive and proliferating cells in the adult brain is still disputable. Persistent progenitors as well as de-differentiating adult cells of various glial lineages are regarded as possible candidates. Pax6 transcription factor is one of the characteristic markers of astroglial de-differentiation, also important for regulation of neural and glial proliferation. Various kinds of pathological stimuli evoke reactive response, differentiated in its morphological, biochemical and immunological character. The aim of this study was to assess the dynamics of astroglial morphological and proliferative response to ischemic injury. One-hour transient focal cerebral ischemia was applied to evoke the reactive astrogliosis in twenty five adult male Wistar rats. The astrocytic morphological and proliferative reactions to ischemia were studied in the period of 6 weeks by means of GFAP and Pax6 immunofluorescent staining. A strong reactive astroglial response was observed in the cerebral cortex and striatum, manifested by GFAP and Pax6 up-regulation and astrocytic hypertrophy. Apparent morphological changes appeared within 24 hrs after ischemia. The GFAP/Pax6 colocalization was numerous and observed 24 hrs after ischemia. A characteristic spatial distribution of GFAP/Pax6 double-labelled astrocytes and Pax6 single-labelled nuclei was revealed, with the latter situated more distantly from the ischemic core. The maximal intensity of astrocytic reaction was present from the first post-ischemic week. Astroglial hypertrophic changes and proliferative reaction were more intense in the striatum than in the cerebral cortex. Our observations reveal intensive astroglial de-differentiation and proliferative response, reflected by dynamic Pax6 up-regulation within GFAP-immunoreactive astrocytes. Transient cerebral ischemia evokes strong reactive astrogliosis, which is apparently differentiated in respect to the post-ischemic period and particular brain structure.

Activation of developmental nuclear fibroblast growth factor receptor 1 signaling and neurogenesis in adult brain by α7 nicotinic receptor agonist.

Reactivation of endogenous neurogenesis in the adult brain or spinal cord holds the key for treatment of central nervous system injuries and neurodegenerative disorders, which are major health care issues for the world's aging population. We have previously shown that activation of developmental integrative nuclear fibroblast growth factor receptor 1 (FGFR1) signaling (INFS), via gene transfection, reactivates neurogenesis in the adult brain by promoting neuronal differentiation of brain neural stem/progenitor cells (NS/PCs). In the present study, we report that targeting the α7 nicotinic acetylcholine receptors (α7nAChRs) with a specific TC-7020 agonist led to a robust accumulation of endogenous FGFR1 in the cell nucleus. Nuclear FGFR1 accumulation was accompanied by an inhibition of proliferation of NS/PCs in the subventricular zone (SVZ) and by the generation of new neurons. Neuronal differentiation was observed in different regions of the adult mouse brain, including (a) ßIII-Tubulin-expressing cortical neurons, (b) calretinin-expressing hippocampal neurons, and (c) cells in substantia nigra expressing the predopaminergic Nurr1+ phenotype. Furthermore, we showed that in vitro stimulation of neural stem/progenitor cells with α7nAChR agonist directly activated INFS and neuronal-like differentiation. TC-7020 stimulation of the ßIII-Tubulin gene was accompanied by increased binding of FGFR1, CREB binding protein, and RNA polymerase II to a Nur77 targeted promoter region. TC-7020 augmented Nur77-dependent activation of nerve growth factor inducible-B protein responsive element, indicating that α7nAChR upregulation of ßIII-Tubulin involves neurogenic FGFR1-Nur signaling. The reactivation of INFS and neurogenesis in adult brain by the α7nAChR agonist may offer a new strategy to treat brain injuries, neurodegenerative diseases, and neurodevelopmental diseases.

α7 nicotinic receptor agonist reactivates neurogenesis in adult brain.

Reactivation of neurogenesis by endogenous Neural Stem/Progenitor Cells (NS/PC) in the adult brain or spinal cord holds the key for treatment of CNS injuries as well as neurodegenerative disorders, which are major healthcare issues for the world's aging population. Recent studies show that targeting the α7 nicotinic acetylcholine receptors (α7nAChR) with a specific TC-7020 agonist inhibits proliferation and stimulates neuronal differentiation of NS/PC in subventricular zone (SVZ) in the adult mouse brain. TC-7020-induced neuronogenesis is observed in different brain regions, including: (1) ßIII Tubulin-expressing cortical neurons, (2) calretinin expressing hippocampal neurons and (3) cells in substantia nigra (SN) expressing predopaminergic Nurr1+phenotype. Reactivation of developmental integrative nuclear FGFR1 signaling (INFS), via gene transfection reinstates neurogenesis in the adult brain by promoting neuronal differentiation of brain NS/PC. TC-7020 neuronogenic effect is associated with a robust accumulation of endogenous FGFR1 in the nuclei of differentiating cells. Furthermore, direct in vitro stimulation of neural stem/progenitor cells with α7nAChR agonist activates INFS and neuronal-like differentiation and activation of neuronal genes. The α7nAChR upregulation of early neuronal ßIII-Tubulin gene involves neurogenic FGFR1-Nur signaling and direct FGFR1 interaction with the gene promoter. The reactivation of developmental INFS and neurogenesis in adult brain by the α7nAChR agonist may offer new strategy to treat brain injuries, neurodegenerative and neurodevelopmental diseases.