Proliferation Of Neural Stem Cells Research Articles

New insights into the role of mild hypoxia in regulating neural stem cell characteristics.

The proliferation of neural stem cells (NSCs) is precisely regulated by extracellular and extracellular environmental factors. In situ hypoxia, one of the key factors involved in the regulation of NSC characteristics, has attracted increasing amounts of attention. Numerous studies have demonstrated that hypoxia can significantly promote the formation of neurospheres and the proliferation of NSCs in vitro and that intermittent hypoxia can promote the proliferation of endogenous NSCs in vivo. In this paper, the effects of different concentrations of oxygen on NSC proliferation and differentiation both in vivo and in vitro are reviewed, and the potential applications of hypoxia-preconditioned NSCs, as well as research progress and challenges in the treatment of central nervous system diseases. are further summarized. Here, the critical role of oxygen in the neurogenesis of NSCs is emphasized, and insights into the use of hypoxia to regulate NSC characteristics are provided.

Tetrahydrofolate attenuates cognitive impairment after hemorrhagic stroke by promoting hippocampal neurogenesis via PTEN signaling.

Intracerebral hemorrhage (ICH), the most common subtype of hemorrhagic stroke, leads to cognitive impairment and imposes significant psychological burdens on patients. Hippocampal neurogenesis has been shown to play an essential role in cognitive function. Our previous study has shown that tetrahydrofolate (THF) promotes the proliferation of neural stem cells (NSCs). However, the effect of THF on cognition after ICH and the underlying mechanisms remain unclear. Here, we demonstrated that administration of THF could restore cognition after ICH. Using Nestin-GFP mice, we further revealed that THF enhanced the proliferation of hippocampal NSCs and neurogenesis after ICH. Mechanistically, we found that THF could prevent ICH-induced elevated level of PTEN and decreased expressions of phosphorylated AKT and mTOR. Furthermore, conditional deletion of PTEN in NSCs of hippocampus attenuated the inhibitory effect of ICH on the proliferation of NSCs and abnormal neurogenesis. Taken together, these results provide molecular insights into ICH-induced cognitive impairment and suggest translational clinical therapeutic strategy for hemorrhagic stroke.Significance Statement Intracerebral hemorrhage (ICH) has been associated with cognitive dysfunction, yet its underlying mechanism remains elusive. Tetrahydrofolate (THF) has shown potential in promoting the proliferation of neural stem cells (NSCs), but its specific impact on cognitive recovery following ICH is still to be confirmed. Through the utilization of the Nestin-GFP genetic marker to track endogenous NSCs in mice, our study revealed that THF could regulate PTEN pathway to ameliorate cognitive impairment post-ICH by enhancing the proliferation of NSCs and sustaining neurogenesis. These findings contribute to valuable insights into the molecular mechanisms involved and suggest potential clinical applications for enhancing cognitive function recovery after ICH.

Salidroside promotes the repair of spinal cord injury by inhibiting astrocyte polarization, promoting neural stem cell proliferation and neuronal differentiation

Spinal cord injury (SCI) remains a formidable challenge, lacking effective treatments. Following SCI, neural stem cells (NSCs) migrate to SCI sites, offering a potential avenue for nerve regeneration, but the effectiveness of this intrinsic repair mechanism remains suboptimal. Salidroside has demonstrated pro-repair attributes in various pathological conditions, including arthritis and cerebral ischemia, and the ability to curtail early-stage inflammation following SCI. However, the specific role of salidroside in the late-stage repair processes of SCI remains less defined. In this investigation, we observed that continuous salidroside treatment in SCI mice improved motor function recovery. Immunofluorescence-staining corroborated salidroside’s capacity to stimulate nerve regeneration and remyelination, suppress glial scar hyperplasia, reduce the activation of neurotoxic A1 astrocytes, and facilitate NSCs migration towards the injured region. Mechanistically, in vitro experiments elucidated salidroside’s significant role in restraining astrocyte proliferation and A1 polarization. It was further established that A1 astrocytes hinder NSCs proliferation while inducing their differentiation into astrocytes. Salidroside effectively ameliorated this inhibition of NSCs proliferation through diminishing c-Jun N-terminal kinase (JNK) pathway phosphorylation and restored their differentiation into neurons by suppressing the signal transducer and activator of transcription 3 (STAT3) pathway. In summary, our findings suggest that salidroside holds promise as a therapeutic agent for traumatic SCI treatment.

Impact of subthalamic nucleus deep brain stimulation at different frequencies on neurogenesis in a rat model of Parkinson's disease

Neurogenesis, play a vital role in neuronal plasticity of adult mammalian brains, and its dysregulation is present in the pathophysiology of Parkinson's disease (PD). While subthalamic nucleus deep brain stimulation (STN-DBS) at various frequencies has been proven effective in alleviating PD symptoms, its influence on neurogenesis remains unclear. This study aimed to investigate the effects of 1-week electrical stimulation at frequencies of 60Hz, 130Hz, and 180Hz on neurogenesis in the subventricular zone (SVZ) of PD rats. A hemiparkinsonian rat model was established using 6-hydroxydopamine and categorized into six groups: control, PD, sham stimulation, 60Hz stimulation, 130Hz stimulation, and 180Hz stimulation. Motor function was assessed using the open field test and rotarod test after one week of STN-DBS at different frequencies. Tyrosine hydroxylase (TH) expression in brain tissue was analyzed via Western blot and immunohistochemistry. Immunofluorescence analysis was conducted to evaluate the expression of BrdU/Sox2, BrdU/GFAP, Ki67/GFAP, and BrdU/DCX in bilateral SVZ and the rostral migratory stream (RMS). Our findings revealed that high-frequency STN-DBS improved motor function. Specifically, stimulation at 130Hz increased dopaminergic neuron survival in the PD rat model, while significantly enhancing the proliferation of neural stem cells (NSCs) and neuroblasts in bilateral SVZ. Moreover, this stimulation effectively facilitated the generation of new NSCs in the ipsilateral RMS and triggered the emergence of fresh neuroblasts in bilateral RMS, with notable presence within the lesioned striatum. Conversely, electrical stimulation at 60Hz and 180Hz did not exhibit comparable effects. The observed promotion of neurogenesis in PD rats following STN-DBS provides valuable insights into the mechanistic basis of this therapeutic approach for PD.

Astrocyte-derived CHI3L1 signaling impairs neurogenesis and cognition in the demyelinated hippocampus

Cognitive dysfunction is a feature in multiple sclerosis (MS), a chronic inflammatory demyelinating disorder. A notable aspect of MS brains is hippocampal demyelination, which is closely associated with cognitive decline. However, the mechanisms underlying this phenomenon remain unclear. Chitinase-3-like (CHI3L1), secreted by activated astrocytes, has been identified as a biomarker for MS progression. Our study investigates CHI3L1's function within the demyelinating hippocampus and demonstrates a correlation between CHI3L1 expression and cognitive impairment in patients with MS. Activated astrocytes release CHI3L1 in reaction to induced demyelination, which adversely affects the proliferation and differentiation of neural stem cells and impairs dendritic growth, complexity, and spine formation in neurons. Our findings indicate that the astrocytic deletion of CHI3L1 can mitigate neurogenic deficits and cognitive dysfunction. We showed that CHI3L1 interacts with CRTH2/receptor for advanced glycation end (RAGE) by attenuating β-catenin signaling. The reactivation of β-catenin signaling can revitalize neurogenesis, which holds promise for therapy of inflammatory demyelination.

Keep calm and make neurons: The effects of glucocorticoids on human cortical neurogenesis

Keep calm and make neurons: The effects of glucocorticoids on human cortical neurogenesis

Subthalamic nucleus but not entopeduncular nucleus deep brain stimulation enhances neurogenesis in the SVZ-olfactory bulb system of Parkinsonian rats.

Deep brain stimulation (DBS) is a highly effective treatment option in Parkinson's disease. However, the underlying mechanisms of action, particularly effects on neuronal plasticity, remain enigmatic. Adult neurogenesis in the subventricular zone-olfactory bulb (SVZ-OB) axis and in the dentate gyrus (DG) has been linked to various non-motor symptoms in PD, e.g., memory deficits and olfactory dysfunction. Since DBS affects several of these non-motor symptoms, we analyzed the effects of DBS in the subthalamic nucleus (STN) and the entopeduncular nucleus (EPN) on neurogenesis in 6-hydroxydopamine (6-OHDA)-lesioned hemiparkinsonian rats. In our study, we applied five weeks of continuous bilateral STN-DBS or EPN-DBS in 6-OHDA-lesioned rats with stable dopaminergic deficits compared to 6-OHDA-lesioned rats with corresponding sham stimulation. We injected two thymidine analogs to quantify newborn neurons early after DBS onset and three weeks later. Immunohistochemistry identified newborn cells co-labeled with NeuN, TH and GABA within the OB and DG. As a putative mechanism, we simulated the electric field distribution depending on the stimulation site to analyze direct electric effects on neural stem cell proliferation. STN-DBS persistently increased the number of newborn dopaminergic and GABAergic neurons in the OB but not in the DG, while EPN-DBS does not impact neurogenesis. These effects do not seem to be mediated via direct electric stimulation of neural stem/progenitor cells within the neurogenic niches. Our data support target-specific effects of STN-DBS on adult neurogenesis, a putative modulator of non-motor symptoms in Parkinson's disease.

Ultra-Low-Dose UV-C Photo-stimulation Promotes Neural Stem Cells Differentiation via Presenilin 1 Mediated Notch and β-Catenin Activation.

Light-based photo-stimulation has demonstrated promising effects on stem cell behavior, particularly in optimizing neurogenesis. However, the precise parameters for achieving optimal results, including the wavelengths, light intensity, radiating energy, and underlying mechanisms, remain incompletely understood. In this study, we focused on utilizing ultraviolet-C (UV-C) at a specific wavelength of 254nm, with an ultra-low dose at intensity of 330μW/cm2 and a total energy of 594mJ/cm2 per day over a period of seven days, to stimulate the proliferation and differentiation of mouse neural stem cells (NSCs). The results revealed that the application of ultra-low-dose UV-C yielded the most significant effect in promoting differentiation when compared to mixed ultraviolet (UV) and ultraviolet-A (UV-A) radiation at equivalent exposure levels. The mechanism exploration elucidated the role of Presenilin 1 in mediating the activation of β-catenin and Notch 1 by the UV-C treatment, both of which are key factors facilitating NSCs proliferation and differentiation. These findings introduce a novel approach employing ultra-low-dose UV-C for specifically enhancing NSC differentiation, as well as the underlying mechanism. It would contribute valuable insights into brain stimulation and neurogenesis modulation for various diseases, offering potential therapeutic avenues for further exploration.

The effects of nutrient-induced quiescence on neural stem cell proliferation in the Drosophila central brain

In the fruit fly, neural stem cells (neuroblasts) residing within a specialized brain niche divide throughout development to produce the adult CNS. Neuroblasts normally transition between a proliferative or quiescent state during development, and this balance is critical for proper tissue growth and neuron production. NBs enter quiescence at the end of embryogenesis when maternal nutrient stores are depleted and reactivate proliferation soon after freshly hatched larvae consume their first meal. This reactivation is regulated by a nutritional checkpoint that requires dietary amino acids. Neuroblasts in larvae maintained on a diet lacking amino acids halt proliferation and production of neurons for extended periods of time, and this state is reversible after reintroduction of amino acids to their diet. Presumably this developmental plasticity is an adaptation that allows mobile larvae to secure another nutrient source, but the extent to which such a delay affects the structure and function of the adult CNS has not been investigated. We used our previously established nutrient deprivation model to halt neuroblast proliferation in larvae for a prolonged period. Using confocal microscopy, we measured the effect of this treatment on both the number of mitotic neuroblasts and how many daughter cells they produced. Both measures of neuroblast proliferation were reduced in delayed larvae compared to controls, despite having access to dietary nutrients for the same amount of time. These results elucidate an uninvestigated aspect of plasticity in the developing CNS and lay the foundation for further functional study of adult brains.

Bisphenol-F and Bisphenol-S (BPF and BPS) Impair the Stemness of Neural Stem Cells and Neuronal Fate Decision in the Hippocampus Leading to Cognitive Dysfunctions.

Neurogenesis occurs throughout life in the hippocampus of the brain, and many environmental toxicants inhibit neural stem cell (NSC) function and neuronal generation. Bisphenol-A (BPA), an endocrine disrupter used for surface coating of plastic products causes injury in the developing and adult brain; thus, many countries have banned its usage in plastic consumer products. BPA analogs/alternatives such as bisphenol-F (BPF) and bisphenol-S (BPS) may also cause neurotoxicity; however, their effects on neurogenesis are still not known. We studied the effects of BPF and BPS exposure from gestational day 6 to postnatal day 21 on neurogenesis. We found that exposure to non-cytotoxic concentrations of BPF and BPS significantly decreased the number/size of neurospheres, BrdU+ (proliferating NSC marker)and MAP-2+ (neuronal marker) cells and GFAP+ astrocytes in the hippocampus NSC culture, suggesting reduced NSC stemness and self-renewal and neuronal differentiation and increased gliogenesis. These analogs also reduced the number of BrdU/Sox-2+, BrdU/Dcx+, and BrdU/NeuN+ co-labeled cells in the hippocampus of the rat brain, suggesting decreased NSC proliferation and impaired maturation of newborn neurons. BPF and BPS treatment increases BrdU/cleaved caspase-3+ cells and Bax-2 and cleaved caspase protein levels, leading to increased apoptosis in hippocampal NSCs. Transmission electron microscopy studies suggest that BPF and BPS also caused degeneration of neuronal myelin sheath, altered mitochondrial morphology, and reduced number of synapses in the hippocampus leading to altered cognitive functions. These results suggest that BPF and BPS exposure decreased the NSC pool, inhibited neurogenesis, induced apoptosis of NSCs, caused myelin degeneration/synapse degeneration, and impaired learning and memory in rats.

Salidroside prevents gestational hypertension-induced impairment of offspring learning and memory via Wnt/Skp2 pathway

BackgroundSalidroside (Sal) has been found to protect against multiple impairments caused by diabetes, and we designed this study to investigate the effect of Sal on gestational hypertension (GHP)-induced impairment of offspring learning and memory. MethodsWe established a GHP rat model by intraperitoneal injection of NG-nitro-L-arginine methyl ester (L-NAME), and treated with Sal by daily gavage. We used Morris Water Maze test to evaluate the learning and memory ability of offspring rats. HE staining was used to measured the pathological changes in hippocampus of offspring. Immunohistochemistry, cellular immunofluorescence and western blot were used to detect the protein expression. ResultsThe learning and memory abilities of GHP offspring rats were significantly lower than those of normal rat offspring, while Sal treatment could significantly improve the learning and memory abilities of GHP offspring rats. HE staining did not reveal pathological differences in the hippocampus of normal rats, GHP rats and Sal-treated GHP offspring rats. However, Sal treatment can significantly increase the expression of Wnt1 and Skp2 protein, and decrease the expression of P27kiwf and P21waf1 protein in the hippocampus of GHP offspring rats. In vitro, Sal significantly promoted the proliferation and differentiation on neural stem cell, while Wnt1 knockdown could reverse these promotions by Sal. In the hippocampus of GHP offspring rats, Sal treatment significantly increased the expression of Tuj1, SOX2, Ki67 and DCX protein. ConclusionSalidroside significantly improves the learning and memory impairment of offspring caused by GHP, and its mechanism may be related to the fact that Salidroside promotes the proliferation and differentiation of neural stem cells by activating the Wnt1/Skp2 signaling pathway.

Linc-NSC affects cell differentiation, apoptosis and proliferation in mouse neural stem cells and embryonic stem cells in vitro and in vivo

BackgroundStem cell therapy is a promising therapeutic strategy. In a previous study, we evaluated tumorigenicity by the stereotactic transplantation of neural stem cells (NSCs) and embryonic stem cells (ESCs) from experimental mice. Twenty-eight days later, there was no evidence of tumor formation or long-term engraftment in the NSCs transplantation group. In contrast, the transplantation of ESCs caused tumor formation; this was due to their high proliferative capacity. Based on transcriptome sequencing, we found that a long intergenic non-coding RNA (named linc-NSC) with unknown structure and function was expressed at 1100-fold higher levels in NSCs than in ESCs. This finding suggested that linc-NSC is negatively correlated with stem cell pluripotency and tumor development, but positively correlated with neurogenesis. In the present study, we investigated the specific role of linc-NSC in NSCs/ESCs in tumor formation and neurogenesis.MethodsWhole transcriptome profiling by RNA sequencing and bioinformatics was used to predict lncRNAs that are widely associated with enhanced tumorigenicity. The expression of linc-NSC was assessed by quantitative real-time PCR. We also performed a number of in vitro methods, including cell proliferation assays, differentiation assays, immunofluorescence assays, flow cytometry, along with in vivo survival and immunofluorescence assays to investigate the impacts of linc-NSC on tumor formation and neurogenesis in NSCs and ESCs.ResultsFollowing the knockdown of linc-NSC in NSCs, NSCs cultured in vitro and those transplanted into the cortex of mice showed stronger survival ability (P < 0.0001), enhanced proliferation(P < 0.001), and reduced apoptosis (P < 0.05); the opposite results were observed when linc-NSC was overexpressed in ESCs. Furthermore, the overexpression of linc-NSC in ECSs induced enhanced apoptosis (P < 0.001) and differentiation (P < 0.01), inhibited tumorigenesis (P < 0.05) in vivo, and led to a reduction in tumor weight (P < 0.0001).ConclusionsOur analyses demonstrated that linc-NSC, a promising gene-edited target, may promote the differentiation of mouse NSCs and inhibit tumorigenesis in mouse ESCs. The knockdown of linc-NSC inhibited the apoptosis in NSCs both in vitro and in vivo, and prevented tumor formation, revealing a new dimension into the effect of lncRNA on low survival NSCs and providing a prospective gene manipulation target prior to transplantation. In parallel, the overexpression of linc-NSC induced apoptosis in ESCs both in vitro and in vivo and attenuated the tumorigenicity of ESCs in vivo, but did not completely prevent tumor formation.

Sustained delivery of NT-3 and curcumin augments microenvironment modulation effects of decellularized spinal cord matrix hydrogel for spinal cord injury repair.

Decellularized extracellular matrix hydrogel, especially that derived from spinal cord (DSCM hydrogel), has been actively considered as a functional biomaterial for remodeling the extracellular matrix of the native tissue, due to its unique characteristics in constructing pro-regenerative microenvironment for neural stem cells (NSCs). Furthermore, DSCM hydrogel can provide multiple binding domains to growth factors and drugs. Therefore, both exogenous neurotrophic factors and anti-inflammatory drugs are highly desired to be incorporated into DSCM hydrogel, which may synergistically modulate the complex microenvironment at the lesion site after spinal cord injury (SCI). Herein, neurotrophin-3 (NT-3) and curcumin (Cur) were integrated into DSCM hydrogel for SCI therapy. Due to different affinities to the DSCM hydrogel, NT-3 underwent a controlled release manner, while curcumin released explosively within the first 24 h, followed by rather sustained but slower release. The integration of both NT-3 and curcumin significantly enhanced NSCs proliferation and their neuronal differentiation. Meanwhile, the release of curcumin promoted macrophages polarization into anti-inflammatory subtypes, which further facilitated NSCs differentiation into neurons. The in situ injected DSCM + NT3 + Cur hydrogel exerted superior capability in alleviating the inflammatory responses in rat contused spinal cord. Compared to DSCM hydrogel alone, DSCM + NT3 + Cur hydrogel more significantly promoted the recruitment of NSCs and their neuronal differentiation at the lesion site. These outcomes favored functional recovery, as evidenced by the improved hind limb movement. Overall, the bioactive DSCM hydrogel can serve as a multifunctional carrier for cooperatively release of growth factors and drugs, which significantly benefits microenvironment regulation and nerve regeneration after SCI.

Calcium and Neural Stem Cell Proliferation.

Intracellular calcium plays a pivotal role in central nervous system (CNS) development by regulating various processes such as cell proliferation, migration, differentiation, and maturation. However, understanding the involvement of calcium (Ca2+) in these processes during CNS development is challenging due to the dynamic nature of this cation and the evolving cell populations during development. While Ca2+ transient patterns have been observed in specific cell processes and molecules responsible for Ca2+ homeostasis have been identified in excitable and non-excitable cells, further research into Ca2+ dynamics and the underlying mechanisms in neural stem cells (NSCs) is required. This review focuses on molecules involved in Ca2+ entrance expressed in NSCs in vivo and in vitro, which are crucial for Ca2+ dynamics and signaling. It also discusses how these molecules might play a key role in balancing cell proliferation for self-renewal or promoting differentiation. These processes are finely regulated in a time-dependent manner throughout brain development, influenced by extrinsic and intrinsic factors that directly or indirectly modulate Ca2+ dynamics. Furthermore, this review addresses the potential implications of understanding Ca2+ dynamics in NSCs for treating neurological disorders. Despite significant progress in this field, unraveling the elements contributing to Ca2+ intracellular dynamics in cell proliferation remains a challenging puzzle that requires further investigation.

A core scientific problem in the treatment of central nervous system diseases: newborn neurons.

It has long been asserted that failure to recover from central nervous system diseases is due to the system's intricate structure and the regenerative incapacity of adult neurons. Yet over recent decades, numerous studies have established that endogenous neurogenesis occurs in the adult central nervous system, including humans'. This has challenged the long-held scientific consensus that the number of adult neurons remains constant, and that new central nervous system neurons cannot be created or renewed. Herein, we present a comprehensive overview of the alterations and regulatory mechanisms of endogenous neurogenesis following central nervous system injury, and describe novel treatment strategies that target endogenous neurogenesis and newborn neurons in the treatment of central nervous system injury. Central nervous system injury frequently results in alterations of endogenous neurogenesis, encompassing the activation, proliferation, ectopic migration, differentiation, and functional integration of endogenous neural stem cells. Because of the unfavorable local microenvironment, most activated neural stem cells differentiate into glial cells rather than neurons. Consequently, the injury-induced endogenous neurogenesis response is inadequate for repairing impaired neural function. Scientists have attempted to enhance endogenous neurogenesis using various strategies, including using neurotrophic factors, bioactive materials, and cell reprogramming techniques. Used alone or in combination, these therapeutic strategies can promote targeted migration of neural stem cells to an injured area, ensure their survival and differentiation into mature functional neurons, and facilitate their integration into the neural circuit. Thus can integration replenish lost neurons after central nervous system injury, by improving the local microenvironment. By regulating each phase of endogenous neurogenesis, endogenous neural stem cells can be harnessed to promote effective regeneration of newborn neurons. This offers a novel approach for treating central nervous system injury.

Effects of microgravity on neural crest stem cells.

Exposure to microgravity (μg) results in a range of systemic changes in the organism, but may also have beneficial cellular effects. In a previous study we detected increased proliferation capacity and upregulation of genes related to proliferation and survival in boundary cap neural crest stem cells (BC) after MASER14 sounding rocket flight compared to ground-based controls. However, whether these changes were due to μg or hypergravity was not clarified. In the current MASER15 experiment BCs were exposed simultaneously to μg and 1 g conditions provided by an onboard centrifuge. BCs exposed to μg displayed a markedly increased proliferation capacity compared to 1 g on board controls, and genetic analysis of BCs harvested 5 h after flight revealed an upregulation, specifically in μg-exposed BCs, of Zfp462 transcription factor, a key regulator of cell pluripotency and neuronal fate. This was associated with alterations in exosome microRNA content between μg and 1 g exposed MASER15 specimens. Since the specimens from MASER14 were obtained for analysis with 1 week's delay, we examined whether gene expression and exosome content were different compared to the current MASER15 experiments, in which specimens were harvested 5 h after flight. The overall pattern of gene expression was different and Zfp462 expression was down-regulated in MASER14 BC μg compared to directly harvested specimens (MASER15). MicroRNA exosome content was markedly altered in medium harvested with delay compared to directly collected samples. In conclusion, our analysis indicates that even short exposure to μg alters gene expression, leading to increased BC capacity for proliferation and survival, lasting for a long time after μg exposure. With delayed harvest of specimens, a situation which may occur due to special post-flight circumstances, the exosome microRNA content is modified compared to fast specimen harvest, and the direct effects from μg exposure may be partially attenuated, whereas other effects can last for a long time after return to ground conditions.

Olfactory three needle regulates the proliferation of olfactory bulb neural stem cells and ameliorates brain injury after subarachnoid hemorrhage by regulating Wnt/β-catenin signaling

BackgroundSubarachnoid hemorrhage (SAH) is a serious cerebrovascular emergency. The incidence of SAH and hazard ratio of death increase with age. ObjectiveIn this study, we aimed to observe the effects and potential mechanisms of olfactory three needle (OTN) on cognitive impairment, neuronal activity, and neural stem cell differentiation in SAH rats. MethodsSprague-Dawley (SD) rats were randomly divided into five groups: Sham, SAH group, SAH + Nimodipine (NMP) group, and SAH + OTN group. The rats in the SAH + OTN group received the OTN electroacupuncture treatment. For treatment with recombinant DKK1 (a Wnt/β-catenin inhibitor), mice were injected with DKK1. ResultsOur results found that OTN improved cognitive impairment and hippocampal neuron damage in SAH rats. Furthermore, OTN promoted the proliferation of neural stem cells in SAH rats. Mechanistically, OTN activated Wnt/β-catenin signaling in SAH rats, as indicated by the increased expression levels of Wnt1, β-Catenin, LMNB1, and p-GSK-3β. DKK1 reversed the improvement effect of OTN on cognitive impairment and neuronal damage in SAH rats. Meanwhile, DKK1 blocked the promoting effect of OTN on the proliferation of NSCs in SAH rats. ConclusionsOTN electroacupuncture may be an effective therapeutic strategy for SAH.

Abstract 7452: ApoE genotype influences susceptibility to doxorubicin-induced cognitive impairment in juvenile rats

Abstract Many pediatric cancer survivors experience chemotherapy-induced cognitive impairment (CICI), which negatively impacts the quality of life. Despite extensive research into the multifactorial causes of CICI, there are no FDA approved drugs available to prevent it and the interpatient variability in susceptibility to CICI is not well understood. Among pediatric cancer survivors, those with the E4 allele of Apolipoprotein E (ApoE) are more likely to exhibit cognitive dysfunction than those with the more prevalent ApoE3 allele, suggesting the ApoE4 allele increases susceptibility to CICI. To mimic a curative pediatric treatment regimen, in our experimental model, five-week-old rats homozygous for either human ApoE3 or ApoE4 allele were treated with doxorubicin (DOXO) (2mg/kg/week for 4 weeks) or saline. ApoE4 rats were more likely than ApoE3 rats to exhibit DOXO-induced impairments in visual memory. However, there was no difference between ApoE3 and ApoE4 rats in sensitivity to DOXO-induced spatial memory impairments. Contrast-enhanced magnetic resonance imaging (MRI) was done to evaluate the blood-brain barrier (BBB) integrity because of literature suggesting that the ApoE4 allele contributes to BBB weakness. However, no significant difference was observed in the BBB integrity between ApoE3 and ApoE4 rats. To delve deeper into the neuropathological basis of DOXO-induced cognitive impairment on the ApoE4 allele, ongoing experiments involve immunohistochemical analyses targeting neurogenic changes in neural stem cell proliferation (DCX), neuronal maturation (Syn and PSD95), as well as glial differentiation (Iba1 and GFAP) in brain regions including hippocampus (dentate gyrus) and cortex. Additionally, to determine the effect of DOXO treatment on ApoE4, we are investigating the role of mitogen-activated protein kinase (MAPK) signaling pathways within brain regions pertinent to memory and recognition. In summary, ApoE genotype contributes to differential susceptibility to CICI. Citation Format: Chadni Patel, Jeremy Willekens, Frank Diglio, Peter Cole. ApoE genotype influences susceptibility to doxorubicin-induced cognitive impairment in juvenile rats [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7452.

Magnetic Nanoparticles and Methylprednisolone Based Physico-Chemical Bifunctional Neural Stem Cells Delivery System for Spinal Cord Injury Repair.

Neural stem cells (NSCs) transplantation is an attractive and promising treatment strategy for spinal cord injury (SCI). Various pathological processes including the severe inflammatory cascade and difficulty in stable proliferation and differentiation of NSCs limit its application and translation. Here, a novel physico-chemical bifunctional neural stem cells delivery system containing magnetic nanoparticles (MNPs and methylprednisolone (MP) is designed to repair SCI, the former regulates NSCs differentiation through magnetic mechanical stimulation in the chronic phase, while the latter alleviates inflammatory response in the acute phase. The delivery system releases MP to promote microglial M2 polarization, inhibit M1 polarization, and reduce neuronal apoptosis. Meanwhile, NSCs tend to differentiate into functional neurons with magnetic mechanical stimulation generated by MNPs in the static magnetic field, which is related to the activation of the PI3K/AKT/mTOR pathway. SCI mice achieve better functional recovery after receiving NSCs transplantation via physico-chemical bifunctional delivery system, which has milder inflammation, higher number of M2 microglia, more functional neurons, and axonal regeneration. Together, this bifunctional NSCs delivery system combined physical mechanical stimulation and chemical drug therapy is demonstrated to be effective, which provides new treatment insights into clinical transformation of SCI repair.

Prosaposin maintains adult neural stem cells in a state associated with deep quiescence

In most vertebrates, adult neural stem cells (NSCs) continuously give rise to neurons in discrete brain regions. A critical process for maintaining NSC pools over long periods of time in the adult brain is NSC quiescence, a reversible and tightly regulated state of cell-cycle arrest. Recently, lysosomes were identified to regulate the NSC quiescence-proliferation balance. However, it remains controversial whether lysosomal activity promotes NSC proliferation or quiescence, and a finer influence of lysosomal activity on NSC quiescence duration or depth remains unexplored. Using RNA sequencing and pharmacological manipulations, we show that lysosomes are necessary for NSC quiescence maintenance. In addition, we reveal that expression of psap, encoding the lysosomal regulator Prosaposin, is enriched in quiescent NSCs (qNSCs) that reside upstream in the NSC lineage and display a deep/long quiescence phase in the adult zebrafish telencephalon. We show that shRNA-mediated psap knockdown increases the proportion of activated NSCs (aNSCs) as well as NSCs that reside in shallower quiescence states (signed by ascl1a and deltaA expression). Collectively, our results identify the lysosomal protein Psap as a (direct or indirect) quiescence regulator and unfold the interplay between lysosomal function and NSC quiescence heterogeneities.