Activation Of Neural Progenitor Cells Research Articles

Low-dose curcumin enhances hippocampal neurogenesis and memory retention in young mice.

Adult neurogenesis generates new functional neurons from adult neural stem cells in various regions, including the subventricular zone (SVZ) of the lateral ventricles and subgranular zone (SGZ) of hippocampal dentate gyrus (DG). Available evidence shows hippocampal neurogenesis can be negatively or positively regulated by dietary components. In a previous study, we reported that curcumin (diferuloylmethane; a polyphenolic found in curry spice) stimulates the proliferation of embryonic neural stem cells (NSCs) by activating adaptive cellular stress responses. Here, we investigated whether subchronic administration of curcumin (once daily at 0.4, 2, or 10mg/kg for 14 days) promotes hippocampal neurogenesis and neurocognitive function in young (5-week-old) mice. Oral administration of low-dose curcumin (0.4mg/kg) increased the proliferation and survival of newly generated cells in hippocampus, but surprisingly, high-dose curcumin (10mg/kg) did not effectively upregulate the proliferation or survival of newborn cells. Furthermore, hippocampal BDNF levels and phosphorylated CREB activity were elevated in only low-dose curcumin-treated mice. Passive avoidance testing revealed that low-dose curcumin increased cross-over latency times, indicating enhanced memory retention, and an in vitro study showed that low-concentration curcumin increased the proliferative activity of neural progenitor cells (NPCs) by upregulating NF1X levels. Collectively, our findings suggest that low-dose curcumin has neurogenic effects and that it may prevent age and neurodegenerative disease-related cognitive deficits.

Science, Medicine, and the Anesthesiologist

Science, Medicine, and the Anesthesiologist

Deep Hypothermic Circulatory Arrest Activates Neural Precursor Cells in the Neonatal Brain

Use of antegrade cerebral perfusion (ACP) as an alternative neuroprotection strategy to deep hypothermic circulatory arrest (DHCA) in the setting of cardiopulmonary bypass in neonates has become a common approach, although the value of ACP over DHCA remains highly debated. This study investigated the disruption to neonatal brain homeostasis by DHCA and ACP. Neonatal pigs (7 days old) undergoing bypass were assigned to 4 groups: DHCA at 18°C and ACP at 18°, 25°, and 32° for 45 minutes (n= 6 per group). ACP was initiated through the innominate artery and maintained at 40 mL/kg/min. After bypass, all animals were maintained sedated and intubated for 24 hours before being euthanized. Brain subventricular zone tissues were analyzed for histologic injury by assessing apoptosis and neural homeostasis (Nestin). Histologic examination showed no significant ischemic/hypoxic neuronal death at any cooling temperature among the 4 treatment groups. However, we detected a significantly higher apoptotic rate in DHCA compared with ACP at 18°C (P= .003-.017) or 25°C (P= .012-.043), whereas apoptosis at 32°C was not different from DHCA. Of note, we identified increased Nestin expression in the DHCA group compared with all ACP groups (P range= .011-.041). Neonatal piglet ACP at 18° or 25°C provides adequate protection from increased brain cellular apoptosis. In contrast to ACP, however, DHCA induces brain Nestin expression, indicating activation of neural progenitor cells and the potential of altering neonatal neurodevelopmental progression. DHCA has potential to more profoundly disrupt neural homeostasis than does ACP.

The genetic architecture of the human cerebral cortex.

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder.

Calcium Activity Dynamics Correlate with Neuronal Phenotype at a Single Cell Level and in a Threshold-Dependent Manner.

Calcium is a ubiquitous signaling molecule that plays a vital role in many physiological processes. Recent work has shown that calcium activity is especially critical in vertebrate neural development. Here, we investigated if calcium activity and neuronal phenotype are correlated only on a population level or on the level of single cells. Using Xenopus primary cell culture in which individual cells can be unambiguously identified and associated with a molecular phenotype, we correlated calcium activity with neuronal phenotype on the single-cell level. This analysis revealed that, at the neural plate stage, a high frequency of low-amplitude spiking activity correlates with an excitatory, glutamatergic phenotype, while high-amplitude spiking activity correlates with an inhibitory, GABAergic phenotype. Surprisingly, we also found that high-frequency, low-amplitude spiking activity correlates with neural progenitor cells and that differentiating cells exhibit higher spike amplitude. Additional methods of analysis suggested that differentiating marker tubb2b-expressing cells exhibit relatively persistent and predictable calcium activity compared to the irregular activity of neural progenitor cells. Our study highlights the value of using a range of thresholds for analyzing calcium activity data and underscores the importance of employing multiple methods to characterize the often irregular, complex patterns of calcium activity during early neural development.

Нейрогенез в зрелом мозге человека. Обоснование терапевтического подхода

Нейроны взрослого мозга, формирующиеся в процессе нейрогенеза, являются непременными участниками важных физиологических процессов. Новые клетки играют важную роль в поддержке когнитивных функций, обучения и памяти. Эндогенная активация нейральных прогениторных клеток отмечена в ответ на патологические изменения - ишемия, нейродегенеративные заболевания, физическая травма, психические расстройства. Однако на фоне большого числа исследований, выполняемых в эксперименте, понимание роли новых клеток в мозге человека остается предметом больших сомнений. Задача данной статьи - проанализировав информацию о нейрогенезе в мозге ЧЕЛОВЕКА, обозначить звенья эндогенной регуляции и обрисовать возможные «мишени» репаративной терапии. Neurons of the adult brain formed in the course of neurogenesis are indispensable participants of important physiological processes. New cells play an important role in supporting cognitive functions, learning and memory. Endogenous activation of neural progenitor cells has been noted to respond to pathological changes, such as ischemia, neurodegenerative diseases, physical trauma, and mental disorders. However, despite a large number of experimental studies, understanding of the role of new cells in human brain remains a matter of great doubt. This review focuses on analyzing information about neurogenesis in the human brain, identifying steps of endogenous regulation, and outlining possible «targets» of reparative therapy.

Blood and brain intertwined during development.

Neurodevelopment![Figure][1] Vascularization helps brain progenitors grow. CREDIT: M. TATA ET AL. , PNAS 113 , 13414 (22 NOVEMEBER 2016) © 2016 NATIONAL ACADEMY OF SCIENCES During brain development, blood vasculature grows rapidly to keep up with growing brain tissue. Studying the mouse hindbrain, Tata et al. show how these events are coordinated. Peak angiogenesis during embryonic development correlates with a surge in mitotic activity of neural progenitor cells. Processes from these cells wrap around developing vessels or tag the perineural vascular plexus. The interaction depends on neuropilin-1 (NRP1), a cell surface receptor that is expressed in endothelial cells of the developing vasculature. Without NRP1, neural progenitor cells fail to proliferate normally, resulting in fewer than normal progenitors and compromising hindbrain growth. Proc. Natl. Acad. Sci. U.S.A. 113, 13414 (2016). [1]: pending:yes

Optical inhibition of striatal neurons promotes focal neurogenesis and neurobehavioral recovery in mice after middle cerebral artery occlusion

Striatal neurons regulate the activity of neural progenitor cells in the subventricular zone, but the effect of striatal neuronal activity on neurogenesis after ischemic stroke is unclear. In this study, we used optogenetic tools to investigate the impact of striatal neuronal activity on the neurogenesis and functional recovery after cerebral ischemia. We transfected striatal neurons with channelrhodopsin-2 or halorhodopsin from Natronomonas so that they can be excited by 473 nm laser or inhibited by 594 nm laser, respectively. Neural inhibition but not excitation at 4–7 days after middle cerebral artery occlusion resulted in reduced atrophy volume (6.8 ± 0.7 vs 8.5 ± 1.2 mm3, p < 0.05) and better performance represented by longer sustaining time on rotarod (99.3 ± 9 vs 80.1 ± 11 s, p < 0.01) and faster moving speed (7.7 ± 2 vs 5.7 ± 1.1 cm/s, p < 0.05) in open field tests. Furthermore, neural inhibition increased the number of nestin+, BrdU+/doublecortin+ and BrdU+/NeuN+ cells (p < 0.001) in the subventricular zone and peri-focal region, and the expression level of axon guidance factor Netrin-1 (0.39 ± 0.16 vs 0.16 ± 0.02, p < 0.05) in the peri-focal region. These data suggest that striatal neuronal activity plays an important role in regulating neurogenesis and neural-behavioral outcomes, and that inhibiting striatal neurons by optogenetics promotes the recovery after ischemic stroke in mice.

Characterization of Proliferating Neural Progenitors after Spinal Cord Injury in Adult Zebrafish.

Zebrafish can repair their injured brain and spinal cord after injury unlike adult mammalian central nervous system. Any injury to zebrafish spinal cord would lead to increased proliferation and neurogenesis. There are presences of proliferating progenitors from which both neuronal and glial loss can be reversed by appropriately generating new neurons and glia. We have demonstrated the presence of multiple progenitors, which are different types of proliferating populations like Sox2+ neural progenitor, A2B5+ astrocyte/ glial progenitor, NG2+ oligodendrocyte progenitor, radial glia and Schwann cell like progenitor. We analyzed the expression levels of two common markers of dedifferentiation like msx-b and vimentin during regeneration along with some of the pluripotency associated factors to explore the possible role of these two processes. Among the several key factors related to pluripotency, pou5f1 and sox2 are upregulated during regeneration and associated with activation of neural progenitor cells. Uncovering the molecular mechanism for endogenous regeneration of adult zebrafish spinal cord would give us more clues on important targets for future therapeutic approach in mammalian spinal cord repair and regeneration.

Role of Yes-associated protein 1 in gliomas: pathologic and therapeutic aspects.

The activation of proline-rich phosphoprotein Yes-associated protein 1 (YAP1) possesses a possible link between stem/progenitor cells, organ size, and cancer. YAP1 has been indicated as an oncoprotein, and overexpression of YAP1 is reported in many human brain tumors, including infiltrating gliomas. During normal brain development, the neurofibromatosis 2 (NF2) protein suppresses YAP1 activity in neural progenitor cells to promote guidepost cell differentiation, but loss of NF2 causes elevating YAP1 activity in midline neural progenitors, which disrupts guidepost formation. Overexpression of endogenous CD44 (cancer stem cell marker) promotes phosphorylation/inactivation of NF2, and upregulates YAP1 expression and leads to cancer cell resistance in glioblastoma. The hippo pathway is also related to the YAP1 action. However, the mechanism of YAP1 action in glioma is still far from clear understanding. Advances in clinical management based on an improved understanding of the function of YAP1 may help to serve as a molecular target in glioma therapeutics. Knockdown of YAP1 by shRNA technology has been shown to reduce glioma in vitro; however, clinical implications are still under investigation. YAP1 can be used as a diagnostic marker for gliomas to monitor the disease status and may help to evaluate its treatment effects. More functional experiments are needed to support the direct roles of YAP1 on gliomas at molecular and cellular levels.

The tumor suppressor Nf2 regulates corpus callosum development by inhibiting the transcriptional coactivator Yap

The corpus callosum connects cerebral hemispheres and is the largest axon tract in the mammalian brain. Callosal malformations are among the most common congenital brain anomalies and are associated with a wide range of neuropsychological deficits. Crossing of the midline by callosal axons relies on a proper midline environment that harbors guidepost cells emitting guidance cues to instruct callosal axon navigation. Little is known about what controls the formation of the midline environment. We find that two components of the Hippo pathway, the tumor suppressor Nf2 (Merlin) and the transcriptional coactivator Yap (Yap1), regulate guidepost development and expression of the guidance cue Slit2 in mouse. During normal brain development, Nf2 suppresses Yap activity in neural progenitor cells to promote guidepost cell differentiation and prevent ectopic Slit2 expression. Loss of Nf2 causes malformation of midline guideposts and Slit2 upregulation, resulting in callosal agenesis. Slit2 heterozygosity and Yap deletion both restore callosal formation in Nf2 mutants. Furthermore, selectively elevating Yap activity in midline neural progenitors is sufficient to disrupt guidepost formation, upregulate Slit2 and prevent midline crossing. The Hippo pathway is known for its role in controlling organ growth and tumorigenesis. Our study identifies a novel role of this pathway in axon guidance. Moreover, by linking axon pathfinding and neural progenitor behaviors, our results provide an example of the intricate coordination between growth and wiring during brain development.

The tumor suppressor Nf2 regulates corpus callosum development by inhibiting the transcriptional coactivator Yap.

The corpus callosum connects cerebral hemispheres and is the largest axon tract in the mammalian brain. Callosal malformations are among the most common congenital brain anomalies and are associated with a wide range of neuropsychological deficits. Crossing of the midline by callosal axons relies on a proper midline environment that harbors guidepost cells emitting guidance cues to instruct callosal axon navigation. Little is known about what controls the formation of the midline environment. We find that two components of the Hippo pathway, the tumor suppressor Nf2 (Merlin) and the transcriptional coactivator Yap (Yap1), regulate guidepost development and expression of the guidance cue Slit2 in mouse. During normal brain development, Nf2 suppresses Yap activity in neural progenitor cells to promote guidepost cell differentiation and prevent ectopic Slit2 expression. Loss of Nf2 causes malformation of midline guideposts and Slit2 upregulation, resulting in callosal agenesis. Slit2 heterozygosity and Yap deletion both restore callosal formation in Nf2 mutants. Furthermore, selectively elevating Yap activity in midline neural progenitors is sufficient to disrupt guidepost formation, upregulate Slit2 and prevent midline crossing. The Hippo pathway is known for its role in controlling organ growth and tumorigenesis. Our study identifies a novel role of this pathway in axon guidance. Moreover, by linking axon pathfinding and neural progenitor behaviors, our results provide an example of the intricate coordination between growth and wiring during brain development.

Permeability transition pore-mediated mitochondrial superoxide flashes mediate an early inhibitory effect of amyloid beta1−42 on neural progenitor cell proliferation

Cellular damage by reactive oxygen species and altered neurogenesis are implicated in the etiology of AD and the pathogenic actions of amyloid β-peptide (Aβ); the underlying mechanisms and the early oxidative intracellular events triggered by Aβ are not established. In the present study, we found that mouse embryonic cortical neural progenitor cells exhibit intermittent spontaneous mitochondrial superoxide (SO) flashes that require transient opening of mitochondrial permeability transition pores (mPTPs). The incidence of mitochondria SO flash activity in neural progenitor cells (NPCs) increased during the first 6–24 hours of exposure to aggregating amyloid β-peptide (Aβ1–42), indicating an increase in transient mPTP opening. Subsequently, the SO flash frequency progressively decreased and ceased between 48 and 72 hours of exposure to Aβ1–42, during which time global cellular reactive oxygen species increased, mitochondrial membrane potential decreased, cytochrome C was released from mitochondria and the cells degenerated. Inhibition of mPTPs and selective reduction in mitochondrial SO flashes significantly ameliorated the negative effects of Aβ1–42 on NPC proliferation and survival. Our findings suggest that mPTP-mediated bursts of mitochondrial SO production is a relatively early and pivotal event in the adverse effects of Aβ1–42 on NPCs. If Aβ inhibits NPC proliferation in the brains of AD patients by a similar mechanism, then interventions that inhibit mPTP-mediated superoxide flashes would be expected to protect NPCs against the adverse effects of Aβ.

Reply to comment on “Activation of neural progenitor cells in human eyes with proliferative vitreoretinopathy” by Johnsen et al. [Exp. Eye Res. 98 (2012) 28–36

Reply to comment on “Activation of neural progenitor cells in human eyes with proliferative vitreoretinopathy” by Johnsen et al. [Exp. Eye Res. 98 (2012) 28–36

Activation of neural progenitor cells in human eyes with proliferative vitreoretinopathy

In addition to the ability for self-renewal and functional differentiation, neural stem/progenitor cells (NSCs) can respond to CNS injuries by targeted migration. In lower vertebrates, retinal injury is known to activate NSCs in the ciliary marginal zone (CMZ). Cells expressing markers of NSCs are also present in the ciliary body epithelium (CE) and in Müller glia in the peripheral retina (PR) of the adult human eye. However, these cells seem to be quiescent in the adult human eye and recent reports have shown that CE cells have limited properties of NSCs. In order to further clarify whether NSCs exist in the adult human eye, we tested whether NSC-like cells could be activated in eyes with proliferative vitreoretinopathy (PVR). The PR and CE were studied for NSC-associated markers in human enucleated control eyes and eyes with confirmed PVR, as well as in a mouse model of PVR. Furthermore, cells isolated from vitreous samples obtained during vitrectomies for retinal detachment were directly fixed or cultured in a stem cell-promoting medium and compared to cells cultured from the post-mortem retina and CE. In situ characterization of the normal eyes revealed robust expression of markers present in NSCs (Nestin, Sox2, Pax6) only around peripheral cysts of the proximal pars plana region and the PR, the latter population also staining for the glial marker GFAP. Although there were higher numbers of dividing cells in the CE of PVR eyes than in controls, we did not detect NSC-associated markers in the CE except around the proximal pars plana cysts. In the mice PVR eyes, Nestin activation was also found in the CE. In human PVR eyes, proliferation of both non-glial and glial cells co-staining NSC-associated markers was evident around the ora serrata region. Spheres formed in 7/10 vitreous samples from patients with PVR compared to 2/15 samples from patients with no known PVR, and expressed glial – and NSC-associated markers both after direct fixation and repetitive passages. In conclusion, the adult human eye may harbor two different populations of neuroepithelial stem/progenitor cells; a non-glial population located in the proximal pars plana around peripheral cysts in addition to a population with Müller glia characteristics. Yet, we only found that the glial population was able to respond to retinal injury by targeted migration into the vitreous.

NLK positively regulates Wnt/β-catenin signalling by phosphorylating LEF1 in neural progenitor cells

Nemo-like kinase (NLK/Nlk) is an evolutionarily conserved protein kinase involved in Wnt/β-catenin signalling. However, the roles of NLK in Wnt/β-catenin signalling in vertebrates remain unclear. Here, we show that inhibition of Nlk2 function in zebrafish results in decreased Lymphoid enhancer factor-1 (Lef1)-mediated gene expression and cell proliferation in the presumptive midbrain, resulting in a reduction of midbrain tectum size. These defects are related to phosphorylation of Lef1 by Nlk2. Thus, Nlk2 is essential for the phosphorylation and activation of Lef1 transcriptional activity in neural progenitor cells (NPCs). In NPC-like mammalian cells, NLK is also required for the phosphorylation and activation of LEF1 transcriptional activity. Phosphorylation of LEF1 induces its dissociation from histone deacetylase, thereby allowing transcription activation. Furthermore, we demonstrate that NLK functions downstream of Dishevelled (Dvl) in the Wnt/β-catenin signalling pathway. Our findings reveal a novel role of NLK in the activation of the Wnt/β-catenin signalling pathway.

Interaction of p24alpha2 with gamma-secretase complex attenuates gamma-cleavage of APP

impairments, suggesting that deficits in neurogenesis may play a role in the disease or contribute to neuropathology. To address this, in this study we examined possible molecular link(s) between neurogenic signaling and FAD proteins.Methods:To determine the significance of APP cleavage by a-secretase and the role of sAPPa in adult neurogenesis we inhibited a-secretase activity in neural progenitor cells using metalloproteinase inhibitor. To determine the role of PS1 in adult neurogenesis we developed a siRNA-expressing lentiviral vector system for the silencing of PS1 in the neurogenic microenvironments in the adult mouse brain. Results: We show that inhibition of a-secretase decreases neural progenitor cell proliferation without affecting their differentiation, and that this decrease can be rescued by sAPPa. In addition, sAPPa can rescue proliferation deficits of neural progenitor cells derived from APP knockout mice. We further show that knocking down PS1 expression in the neurogenic niches of the adult brain enhances cell cycle exit of neural progenitor cell and induces their differentiation. Neural progenitor cells expressing reduced levels of PS1 could differentiate into neurons and glia. Conclusions: This study suggests that sAPPa and PS1 regulate neural progenitor cell maintenance in the adult brain. The results of these studies imply that FAD-linked mutations may alter neurogenic processes in Alzheimer’s disease.

Granulocyte macrophage-colony stimulating factor shows anti-apoptotic activity in neural progenitor cells via JAK/STAT5-Bcl-2 pathway

Recently, many studies have shown that granulocyte macrophage-colony stimulating factor (GM-CSF) has anti-apoptotic activity and regulates the expression of anti-apoptotic genes including Bcl-2 family proteins in neuronal cells in vitro and in vivo. This study investigated detailed mechanism of GM-CSF involved in its anti-apoptotic activity and regulation of Bcl-2 expression in neural progenitor cells (NPCs) as a model. NPCs were cultured from the brain of E13 ICR mouse. When NPCs were treated with staurosporine at 1μM, apoptosis occurred in more than 30% of cells in TUNEL assay. However, apoptosis was significantly inhibited by pre-treatment with GM-CSF at 10 ng/ml. Under the same experimental condition, the expression of both Bcl-2 and Bcl-xl was clearly induced by GM-CSF regardless of staurosporine treatment in RT-PCR and Western blot analyses. GM-CSF was shown to induce the expression of Bcl-2 and Bcl-xl via Janus tyrosine kinase (JAK) but not via phosphatidylinositol 3-kinase (PI3K) or RAS-mitogen activated protein kinase kinase-1 (MEK-1) using specific signal pathway inhibitors. Further analyses showed that the expression of Bcl-2 and Bcl-xl was induced by GM-CSF via signal transducers and activators of transcription 5 (STAT5) and STAT3, respectively. In addition, JAK/STAT5-Bcl-2 pathway but not JAK/STAT3-Bcl-xl pathway was responsible for the anti-apoptotic activity of GM-CSF in NPCs in TUNEL assay. To our knowledge, this study is the first report that shows differential roles of Bcl-2 and Bcl-xl, and their regulation mechanism involved in the anti-apoptotic activity of GM-CSF in NPCs.

Cilostazol attenuates ischemic brain injury and enhances neurogenesis in the subventricular zone of adult mice after transient focal cerebral ischemia

Evidence suggests that neurogenesis occurs in the adult mammalian brain, and that various stimuli, for example, ischemia/hypoxia, enhance the generation of neural progenitor cells in the subventricular zone (SVZ) and their migration into the olfactory bulb. In a mouse stroke model, focal ischemia results in activation of neural progenitor cells followed by their migration into the ischemic lesion. The present study assessed the in vivo effects of cilostazol, a type 3 phosphodiesterase inhibitor known to activate the cAMP-responsive element binding protein (CREB) signaling, on neurogenesis in the ipsilateral SVZ and peri-infarct area in a mouse model of transient middle cerebral artery occlusion. Mice were divided into sham operated ( n=12), vehicle- ( n=18) and cilostazol-treated ( n=18) groups. Sections stained for 5-bromodeoxyuridine (BrdU) and several neuronal and a glial markers were analyzed at post-ischemia days 1, 3 and 7. Cilostazol reduced brain ischemic volume ( P<0.05) and induced earlier recovery of neurologic deficit ( P<0.05). Cilostazol significantly increased the density of BrdU-positive newly-formed cells in the SVZ compared with the vehicle group without ischemia. Increased density of doublecortin (DCX)-positive and BrdU/DCX-double positive neural progenitor cells was noted in the ipsilateral SVZ and peri-infarct area at 3 and 7 days after focal ischemia compared with the vehicle group ( P<0.05). Cilostazol increased DCX-positive phosphorylated CREB (pCREB)-expressing neural progenitor cells, and increased brain derived neurotrophic factor (BDNF)-expressing astrocytes in the ipsilateral SVZ and peri-infarct area. The results indicated that cilostazol enhanced neural progenitor cell generation in both ipsilateral SVZ and peri-infarct area through CREB-mediated signaling pathway after focal ischemia.

Characterization of nestin expression in the spinal cord of GFP transgenic mice after peripheral nerve injury

Many studies have shown that activation and increase in the number of astrocytes and microglia in the spinal cord participate in the initiation and maintenance of neuropathic pain, but little attention has been paid to the responses of neural progenitor cells to peripheral nerve injury. Nestin, a class VI intermediate filament protein, is expressed both in neuronal and glial progenitors as well as in their common precursors; and nestin-positive cells appear in the brain and spinal cord following various forms of damage to these regions. To clarify the responses of neural progenitor cells to nerve injury, we applied L5 spinal nerve transection (L5-SNT) to nestin-promoter GFP (pNestin-GFP) transgenic mice to narrow the target to them. While pNestin-GFP expression was strongly retained in the ependyma lining the central canal of the transgenic spinal cord even in adulthood, it was markedly reduced in the dorsal horn during postnatal development by day 7. Increases in pNestin-GFP expression and labeling by the proliferation marker 5-bromodeoxyuridine were broadly found in the dorsal horn of adult mice on day 3 after L5-SNT. On the other hand, the activation and increase in number of microglia and astrocytes are restricted to the superficial layer of the dorsal horn, the central terminal of injured primary afferent fibers. Purinergic P2X agonist α, β-MeATP increased [Ca2+]i in nestin-positive cells in the superficial layer ipsilateral to nerve injury and P2 receptor antagonists suramin and pyridoxalphosphate-6-azophenyl-2,4-disulphonic acid (PPADS) blocked the expression and elongation of pNestin-GFP fibers in the slice culture of the spinal cord. These results with pNestin-GFP transgenic mice demonstrate that nestin-positive cells proliferate in the dorsal horn in response to peripheral nerve injury and suggest that ATP may contribute to the expression of nestin and activation of neural progenitor cells after nerve injury.