Human Stem Research Articles

Diethyldithiocarbamate-ferrous oxide nanoparticles inhibit human and mouse glioblastoma stemness: aldehyde dehydrogenase 1A1 suppression and ferroptosis induction.

The development of effective therapy for eradicating glioblastoma stem cells remains a major challenge due to their aggressive growth, chemoresistance and radioresistance which are mainly conferred by aldehyde dehydrogenase (ALDH)1A1. The latter is the main stemness mediator via enhancing signaling pathways of Wnt/β-catenin, phosphatidylinositol 3-kinase/AKT, and hypoxia. Furthermore, ALDH1A1 mediates therapeutic resistance by inactivating drugs, stimulating the expression of drug efflux transporters, and detoxifying reactive radical species, thereby apoptosis arresting. Recent reports disclosed the potent and broad-spectrum anticancer activities of the unique nanocomplexes of diethyldithiocarbamate (DE, ALDH1A1 inhibitor) with ferrous oxide nanoparticles (FeO NPs) mainly conferred by inducing lipid peroxidation-dependent non-apoptotic pathways (iron accumulation-triggered ferroptosis), was reported. Accordingly, the anti-stemness activity of nanocomplexes (DE-FeO NPs) was investigated against human and mouse glioma stem cells (GSCs) and radioresistant GSCs (GSCs-RR). DE-FeO NPs exhibited the strongest growth inhibition effect on the treated human GSCs (MGG18 and JX39P), mouse GSCs (GS and PDGF-GSC) and their radioresistant cells (IC50 ≤ 70 and 161μg/mL, respectively). DE-FeO NPs also revealed a higher inhibitory impact than standard chemotherapy (temozolomide, TMZ) on self-renewal, cancer repopulation, chemoresistance, and radioresistance potentials. Besides, DE-FeO NPs surpassed TMZ regarding the effect on relative expression of all studied stemness genes, as well as relative p-AKT/AKT ratio in the treated MGG18, GS and their radioresistant (MGG18-RR and GS-RR). This potent anti-stemness influence is primarily attributed to ALDH1A1 inhibition and ferroptosis induction, as confirmed by significant elevation of cellular reactive oxygen species and lipid peroxidation with significant depletion of glutathione and glutathione peroxidase 4. DE-FeO NPs recorded the optimal LogP value for crossing the blood brain barrier. This in vitro novel study declared the potency of DE-FeO NPs for collapsing GSCs and GSCs-RR with improving their sensitivity to chemotherapy and radiotherapy, indicating that DE-FeO NPs may be a promising remedy for GBM. Glioma animal models will be needed for in-depth studies on its safe effectiveness.

Effects of nanomolar methylmercury on developing human neural stem cells and zebrafish Embryo

Exposure to mercury and its organic form methylmercury (MeHg), is of great concern for the developing nervous system. Despite available literature on MeHg neurotoxicity, there is still uncertainty about its mechanisms of action and the doses that trigger developmental effects. Our study combines two alternative methodologies, the human neural stem cells (NSC) and the zebrafish (ZF) embryo, to address the neurotoxic effects of early exposure to nanomolar concentrations of MeHg. Our results show linear or nonmonotonic (hormetic) responses depending on studied parameters. In ZF, we observed a hormetic response in locomotion and larval rotation, but a concentration-dependent response for sensory organ size and habituation. We also observed a possible delayed response as MeHg had greater effects on larval activity at 5 days than at 24 h. In NSC cells, some parameters show a clear dose dependence, such as increased apoptosis and differentiation to glial cells or decreased neuronal precursors; while others show a hormetic response: neuronal differentiation or cell proliferation. This study shows that the ZF model was more susceptible than NSC to MeHg neurotoxicity. The combination of different models has improved the understanding of the underlying mechanisms of toxicity and possible compensatory mechanisms at the cellular and organismal level.

SNHG1 knockdown promotes osteogenic differentiation of hDFSCs through anti-oxidative stress mediated by autophagy.

The long noncoding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) plays a crucial role in tumorigenesis and is frequently employed as a prognostic biomarker. However, its involvement in the osteogenic differentiation of oral stem cells, particularly human dental follicle stem cells (hDFSCs), remains unclear. Our investigation revealed that the absence of SNHG1 enhances the osteogenic differentiation of hDFSCs. Furthermore, the downregulation of SNHG1 induces autophagy in hDFSCs, leading to a reduction in intracellular oxidative stress levels. Notably, this effect is orchestrated through the epigenetic regulation of EZH2. Our study unveils a novel function of SNHG1 in governing the osteogenic differentiation of hDFSCs, offering fresh insights for an in-depth exploration of the molecular mechanisms underlying dental follicle development. These findings not only provide a foundation for advancing the understanding of SNHG1 but also present innovative perspectives for promoting the repair and regeneration of periodontal supporting tissue, ultimately contributing to the restoration of periodontal health and tooth function.

Endogenous tagging using split mNeonGreen in human iPSCs for live imaging studies

Endogenous tags have become invaluable tools to visualize and study native proteins in live cells. However, generating human cell lines carrying endogenous tags is difficult due to the low efficiency of homology-directed repair. Recently, an engineered split mNeonGreen protein was used to generate a large-scale endogenous tag library in HEK293 cells. Using split mNeonGreen for large-scale endogenous tagging in human iPSCs would open the door to studying protein function in healthy cells and across differentiated cell types. We engineered an iPS cell line to express the large fragment of the split mNeonGreen protein (mNG21-10) and showed that it enables fast and efficient endogenous tagging of proteins with the short fragment (mNG211). We also demonstrate that neural network-based image restoration enables live imaging studies of highly dynamic cellular processes such as cytokinesis in iPSCs. This work represents the first step towards a genome-wide endogenous tag library in human stem cells.

Endogenous tagging using split mNeonGreen in human iPSCs for live imaging studies.

Endogenous tags have become invaluable tools to visualize and study native proteins in live cells. However, generating human cell lines carrying endogenous tags is difficult due to the low efficiency of homology-directed repair. Recently, an engineered split mNeonGreen protein was used to generate a large-scale endogenous tag library in HEK293 cells. Using split mNeonGreen for large-scale endogenous tagging in human iPSCs would open the door to studying protein function in healthy cells and across differentiated cell types. We engineered an iPS cell line to express the large fragment of the split mNeonGreen protein (mNG21-10) and showed that it enables fast and efficient endogenous tagging of proteins with the short fragment (mNG211). We also demonstrate that neural network-based image restoration enables live imaging studies of highly dynamic cellular processes such as cytokinesis in iPSCs. This work represents the first step towards a genome-wide endogenous tag library in human stem cells.

A comprehensive review: synergizing stem cell and embryonic development knowledge in mouse and human integrated stem cell-based embryo models.

Mammalian stem cell-based embryo models have emerged as innovative tools for investigating early embryogenesis in both mice and primates. They not only reduce the need for sacrificing mice but also overcome ethical limitations associated with human embryo research. Furthermore, they provide a platform to address scientific questions that are otherwise challenging to explore in vivo. The usefulness of a stem cell-based embryo model depends on its fidelity in replicating development, efficiency and reproducibility; all essential for addressing biological queries in a quantitative manner, enabling statistical analysis. Achieving such fidelity and efficiency requires robust systems that demand extensive optimization efforts. A profound understanding of pre- and post-implantation development, cellular plasticity, lineage specification, and existing models is imperative for making informed decisions in constructing these models. This review aims to highlight essential differences in embryo development and stem cell biology between mice and humans, assess how these variances influence the formation of partially and fully integrated stem cell models, and identify critical challenges in the field.

Aquaporins enriched in endothelial vacuole membrane regulate the diameters of microvasculature in hyperglycemia.

In patients with diabetic microvascular complications, decreased perfusion or vascular occlusion, caused by reduced vascular diameter, is a common characteristic that will lead to insufficient blood supply. Yet, the regulatory mechanism and effective treatment approach remain elusive. Our initial findings revealed a notable decrease in the expression of human AQP1 in both diabetic human retina samples (49 healthy vs. 54 diabetic samples) and high-glucose-treated human retinal microvascular endothelial cells. Subsequently, our investigations unveiled a reduction in vascular diameter and compromised perfusion within zebrafish embryos subjected to high glucose treatment. Further analysis indicated a significant downregulation of two aquaporins, aqp1a.1 and aqp8a.1, which are highly enriched in ECs and are notably responsive to hyperglycemic conditions. Intriguingly, the loss of function of aqp1a.1 and/or aqp8a.1 resulted in a reduction of intersegmental vessel diameters, effectively mirroring the phenotype observed in the hyperglycemic zebrafish model.The overexpression of aqp1a.1/aqp8a.1 in zebrafish ECs led to notable enlargement of microvascular diameters. Moreover, the reduced vessel diameters resulting from high-glucose treatment were effectively rescued by the overexpression of these aquaporins. Additionally, both aqp1a.1 and apq8a.1 were localized in the intracellular vacuoles in cultured ECs as well as the ECs of sprouting ISVs, and the loss of Aqps caused the reduction of those vacuoles, which was required for lumenization. Notably, while the loss of AQP1 did not impact EC differentiation from human stem cells, it significantly inhibited vascular formation in differentiated ECs. EC-enriched aquaporins regulate the diameter of blood vessels through an intracellular vacuole-mediated process under hyperglycemic conditions. These findings collectively suggest that aquaporins expressed in ECs hold significant promise as potential targets for gene therapy aimed at addressing vascular perfusion defects associated with diabetes.

Evaluation puramatrix as a 3D microenvironment for neural differentiation of human breastmilk stem cells

The extracellular matrix is recognized as an efficient and determining component in the growth, proliferation, and differentiation of cells due to its ability to perceive and respond to environmental signals. Applying three-dimensional scaffolds can create conditions similar to the extracellular matrix and provide an opportunity to investigate cell fate. In this study, we employed the PuraMatrix hydrogel scaffold as an advanced cell culture platform for the neural differentiation of stem cells derived from human breastmilk to design an opportune model for tissue engineering.Isolated stem cells from breastmilk were cultured and differentiated into neural-like cells on PuraMatrix peptide hydrogel and in the two-dimensional system. The compatibility of breastmilk-derived stem cells with PuraMatrix and cell viability was evaluated by scanning electron microscopy and MTT assay, respectively. Induction of differentiation was achieved by exposing cells to the neurogenic medium. After 21 days of the initial differentiation process, the expression levels of glial fibrillary acidic protein (GFAP), microtubule-associated protein (MAP2), β-tubulin III, and neuronal nuclear antigen (NeuN) were analyzed using the immunostaining technique.The results illustrated a notable expression of MAP2, β-tubulin-III, and NeuN in the three-dimensional cell culture in comparison to the two-dimensional system, indicating the beneficial effect of PuraMatrix scaffolds in the process of differentiating breastmilk-derived stem cells into neural-like cells.In view of the obtained results, the combination of breastmilk-derived stem cells and PuraMatrix hydrogel scaffold could be an advisable preference for neural tissue regeneration and cell therapy.

Characterization and optimization of variability in a human colonic epithelium culture model.

Animal models have historically been poor preclinical predictors of gastrointestinal (GI) directed therapeutic efficacy and drug-induced GI toxicity. Human stem and primary cell-derived culture systems are a major focus of efforts to create biologically relevant models that enhance preclinical predictive value of intestinal efficacy and toxicity. The inherent variability in stem-cell-based cultures makes development of useful models a challenge; the stochastic nature of stem-cell differentiation interferes with the ability to build and validate reproducible assays that query drug responses and pharmacokinetics. In this study, we aimed to characterize and reduce sources of variability in a complex stem cell-derived intestinal epithelium model, termed RepliGut® Planar, across cells from multiple human donors, cell lots, and passage numbers. Assessment criteria included barrier formation and integrity, gene expression, and cytokine responses. Gene expression and culture metric analyses revealed that controlling cell passage number reduces variability and maximizes physiological relevance of the model. In a case study where passage number was optimized, distinct cytokine responses were observed among four human donors, indicating that biological variability can be detected in cell cultures originating from diverse human sources. These findings highlight key considerations for designing assays that can be applied to additional primary-cell derived systems, as well as establish utility of the RepliGut® Planar platform for robust development of human-predictive drug-response assays.

Enhanced Vascular-like Network Formation of Encapsulated HUVECs and ADSCs Coculture in Growth Factors Conjugated GelMA Hydrogels.

Tissue engineering primarily aimed to alleviate the insufficiency of organ donations worldwide. Nonetheless, the survival of the engineered tissue is often compromised due to the complexity of the natural organ architectures, especially the vascular system inside the organ, which allows food-waste transfer. Thus, vascularization within the engineered tissue is of paramount importance. A critical aspect of this endeavor is the ability to replicate the intricacies of the extracellular matrix and promote the formation of functional vascular networks within engineered constructs. In this study, human adipose-derived stem cells (hADSCs) and human umbilical vein endothelial cells (HUVECs) were cocultured in different types of gelatin methacrylate (GelMA). In brief, pro-angiogenic signaling growth factors (GFs), vascular endothelial growth factor (VEGF165) and basic fibroblast growth factor (bFGF), were conjugated onto GelMA via an EDC/NHS coupling reaction. The GelMA hydrogels conjugated with VEGF165 (GelMA@VEGF165) and bFGF (GelMA@bFGF) showed marginal changes in the chemical and physical characteristics of the GelMA hydrogels. Moreover, the conjugation of these growth factors demonstrated improved cell viability and cell proliferation within the hydrogel construct. Additionally, vascular-like network formation was observed predominantly on GelMA@GrowthFactor (GelMA@GF) hydrogels, particularly on GelMA@bFGF. This study suggests that growth factor-conjugated GelMA hydrogels would be a promising biomaterial for 3D vascular tissue engineering.

Assessment of the anti-inflammatory and biological properties of Bioroot Flow: A novel bioceramic sealer.

IntroductionBioRoot Flow (BRF) is a novel premixed bioceramic sealer indicated for endodontic treatments, but the biological and immunomodulatory effects of this endodontic sealer on human periodontal ligament stem cells (hPDLSCs) have not been elucidated. MethodsTo ascertain the biological impact of BRF, TotalFill BC Sealer (TFbc), and AH Plus (AHP) on human Periodontal Ligament Stem Cells (hPDLSCs), assessments were conducted to evaluate the cytocompatibility, cellular proliferation, migratory capacity, osteo/cementogenic differentiation potential, the ability to form mineralized nodules, and the immunomodulatory characteristics of hPDLSCs following treatment with these endodontic sealers. ResultsBiological assays showed adequate cell metabolic activity and cell migration in BRF, while SEM assay evidenced that TFbc and BRF groups demonstrated a superior cell adhesion process, including substrate adhesion, cytoskeleton development, and spreading on the niche-like structures of the cement as compared to the AHP group. TFbc and BRF-treated groups exhibited a significantly lower IL6 and IL8 production than AHP (* p <.05). The bioceramic sealers stimulated heightened expression of BSP, CEMP-1, and CAP genes within a 7–14 day period. Notably, BRF and TFbc demonstrated a significant enhancement in the mineralization of hPDLSCs when compared to the negative control. Among these, cells treated with BRF showed a more substantial accumulation of calcium (*** p < .001). ConclusionsTaken together, these findings indicate that BRF can potentially enhance cell differentiation by promoting the expression of essential genes related to bone and cement formation. In addition, BRF and TFbc displayed anti-inflammatory effects.

Characterization of gene regulatory networks underlying key properties in human hematopoietic stem cell ontogeny.

Human hematopoiesis starts at early yolk sac and undergoes site- and stage-specific changes over development. The intrinsic mechanism underlying property changes in hematopoiesis ontogeny remains poorly understood. Here, we analyzed single-cell transcriptome of human primary hematopoietic stem/progenitor cells (HSPCs) at different developmental stages, including yolk-sac (YS), AGM, fetal liver (FL), umbilical cord blood (UCB) and adult peripheral blood (PB) mobilized HSPCs. These stage-specific HSPCs display differential intrinsic properties, such as metabolism, self-renewal, differentiating potentialities etc. We then generated highly co-related gene regulatory network (GRNs) modules underlying the differential HSC key properties. Particularly, we identified GRNs and key regulators controlling lymphoid potentiality, self-renewal as well as aerobic respiration in human HSCs. Introducing selected regulators promotes key HSC functions in HSPCs derived from human pluripotent stem cells. Therefore, GRNs underlying key intrinsic properties of human HSCs provide a valuable guide to generate fully functional HSCs in vitro.

A Hybrid Scaffold Induces Chondrogenic Differentiation and Enhances In Vivo Cartilage Regeneration.

Extensively researched tissue engineering strategies involve incorporating cells into suitable biomaterials, offering promising alternatives to boost tissue repair. In this study, a hybrid scaffold, Gel-DCM, which integrates a photoreactive gelatin-hyaluronic acid hydrogel (Gel) with an oriented porous decellularized cartilage matrix (DCM), was designed to facilitate chondrogenic differentiation and cartilage repair. The Gel-DCM exhibited excellent biocompatibility in vitro, promoting favorable survival and growth of human adipose-derived stem cells (hADSCs) and articular chondrocytes (hACs). Gene expression analysis indicated that the hACs expanded within the Gel-DCM exhibited enhanced chondrogenic phenotype. In addition, Gel-DCM promoted chondrogenesis of hADSCs without the supplementation of exogenous growth factors. Following this, invivo experiments were conducted where empty Gel-DCM or Gel-DCM loaded with hACs/hADSCs were used and implanted to repair osteochondral defects in a rat model. In the control group, no implants were delivered to the injury site. Interestingly, macroscopic, histological, and microcomputed tomography scanning results revealed superior cartilage restoration and subchondral bone reconstruction in the empty Gel-DCM group compared with the control group. Moreover, both hACs-loaded and hADSCs-loaded Gel-DCM implants exhibited superior repair of hyaline cartilage and successful reconstruction of subchondral bone, whereas defects in the control groups were predominantly filled with fibrous tissue. These observations suggest that the Gel-DCM can provide an appropriate three-dimensional chondrogenic microenvironment, and its combination with reparative cell sources, ACs or ADSCs, holds great potential for facilitating cartilage regeneration.

EGFR-dependent endocytosis of Wnt9a and Fzd9b promotes β-catenin signaling during hematopoietic stem cell development in zebrafish.

Cell-to-cell communication through secreted Wnt ligands that bind to members of the Frizzled (Fzd) family of transmembrane receptors is critical for development and homeostasis. Wnt9a signals through Fzd9b, the co-receptor LRP5 or LRP6 (LRP5/6), and the epidermal growth factor receptor (EGFR) to promote early proliferation of zebrafish and human hematopoietic stem cells during development. Here, we developed fluorescently labeled, biologically active Wnt9a and Fzd9b fusion proteins to demonstrate that EGFR-dependent endocytosis of the ligand-receptor complex was required for signaling. In human cells, the Wnt9a-Fzd9b complex was rapidly endocytosed and trafficked through early and late endosomes, lysosomes, and the endoplasmic reticulum. Using small-molecule inhibitors and genetic and knockdown approaches, we found that Wnt9a-Fzd9b endocytosis required EGFR-mediated phosphorylation of the Fzd9b tail, caveolin, and the scaffolding protein EGFR protein substrate 15 (EPS15). LRP5/6 and the downstream signaling component AXIN were required for Wnt9a-Fzd9b signaling but not for endocytosis. Knockdown or loss of EPS15 impaired hematopoietic stem cell development in zebrafish. Other Wnt ligands do not require endocytosis for signaling activity, implying that specific modes of endocytosis and trafficking may represent a method by which Wnt-Fzd specificity is established.

Locally released H2 and O2 from an artificial periosteum modulate the survival and reparative activities of stem cells derived from the aged human nasal mucosa after transplantation

Stem cell therapies are limited by poor cell survival and engraftment. Elderly diabetic patients (EDPs) have a greater risk of bone graft failure. Herein, a g-C3N4/polydopamine (PDA@g-C3N4) composite nanosheet was successfully fabricated via in situ polymerization of PDA on a g-C3N4 surface. Then, the PDA/g-C3N4 composite was crosslinked with a fibrin hydrogel to prepare an artificial periosteum for EDPs. With the help of NIR, we showed that the synthetic artificial periosteum released H2 and O2 and enhanced the survival and osteogenic differentiation of aged human nasal mucosa-derived ectodermal stem cells (hEMSCs) in microenvironments characterized by oxidative stress and hypoxia. The artificial periosteum had pleiotropic effects on aged hEMSC reparative activities, modulating cytokine secretion and the protein expression of effectors associated with vascularization, and bone formation in vivo. Our findings imply that the developed artificial periosteum loaded with hEMSCs has great promise for the repair of bone defects in EDPs.

An improved method for generating human spinal cord neural stem cells

Neural stem cells have exhibited efficacy in pre-clinical models of spinal cord injury (SCI) and are on a translational path to human testing. We recently reported that neural stem cells must be driven to a spinal cord fate to optimize host axonal regeneration into sites of implantation in the injured spinal cord, where they subsequently form neural relays across the lesion that support significant functional improvement. We also reported methods of deriving and culturing human spinal cord neural stem cells derived from embryonic stem cells that can be sustained over serial high passage numbers in vitro, providing a potentially optimized cell source for human clinical trials. We now report further optimization of methods for deriving and sustaining cultures of human spinal cord neural stem cell lines that result in improved karyotypic stability while retaining anatomical efficacy in vivo. This development improves prospects for safe human translation.

Cytoskeletal rearrangement precedes nucleolar remodeling during adipogenesis

Differentiation of adipose progenitor cells into mature adipocytes entails a dramatic reorganization of the cellular architecture to accommodate lipid storage into cytoplasmic lipid droplets. Lipid droplets occupy most of the adipocyte volume, compressing the nucleus beneath the plasma membrane. How this cellular remodeling affects sub-nuclear structure, including size and number of nucleoli, remains unclear. We describe the morphological remodeling of the nucleus and the nucleolus during in vitro adipogenic differentiation of primary human adipose stem cells. We find that cell cycle arrest elicits a remodeling of nucleolar structure which correlates with a decrease in protein synthesis. Strikingly, triggering cytoskeletal rearrangements mimics the nucleolar remodeling observed during adipogenesis. Our results point to nucleolar remodeling as an active, mechano-regulated mechanism during adipogenic differentiation and demonstrate a key role of the actin cytoskeleton in defining nuclear and nucleolar architecture in differentiating human adipose stem cells.

Long-Term Mouse Spinal Cord Organotypic Slice Culture as a Platform for Validating Cell Transplantation in Spinal Cord Injury.

Resolutive cures for spinal cord injuries (SCIs) are still lacking, due to the complex pathophysiology. One of the most promising regenerative approaches is based on stem cell transplantation to replace lost tissue and promote functional recovery. This approach should be further explored better in vitro and ex vivo for safety and efficacy before proceeding with more expensive and time-consuming animal testing. In this work, we show the establishment of a long-term platform based on mouse spinal cord (SC) organotypic slices transplanted with human neural stem cells to test cellular replacement therapies for SCIs. Standard SC organotypic cultures are maintained for around 2 or 3 weeks in vitro. Here, we describe an optimized protocol for long-term maintenance (≥30 days) for up to 90 days. The medium used for long-term culturing of SC slices was also optimized for transplanting neural stem cells into the organotypic model. Human SC-derived neuroepithelial stem (h-SC-NES) cells carrying a green fluorescent protein (GFP) reporter were transplanted into mouse SC slices. Thirty days after the transplant, cells still show GFP expression and a low apoptotic rate, suggesting that the optimized environment sustained their survival and integration inside the tissue. This protocol represents a robust reference for efficiently testing cell replacement therapies in the SC tissue. This platform will allow researchers to perform an ex vivo pre-screening of different cell transplantation therapies, helping them to choose the most appropriate strategy before proceeding with in vivo experiments.

Human neural stem cell secretome relieves endoplasmic reticulum stress-induced apoptosis and improves neuronal functions after traumatic brain injury in a rat model.

Neural stem cell secretome (NSC-S) plays an important role in neuroprotection and recovery. Studies have shown that endoplasmic reticulum stress (ER stress) is involved in the progression of traumatic brain injury (TBI) and is a crucial cause of secondary damage and neuronal death after brain injury. Whether NSC-S is engaged in ER stress and ER stress-mediated neuronal apoptosis post-TBI has not been investigated. In the study, the Feeney SD male rat model was established. The results showed that NSC-S treatment significantly improved the behavior of rats with TBI. In addition, NSC-S relieved ER stress in TBI rats and was observed by transmission electron microscopy and western blot. The specific mechanism was further elucidated that restoration was achieved by alleviating the PERK-eIF2α pathway and thus protecting neurons from apoptosis. Notably, the discovery of calumenin (CALU) in NSC-S by liquid chromatography-tandem mass spectrometry (LC-MS/MS/MS) may be related to the protective effect of NSC-S on ER stress in neurons. Also, the mechanism by which it functions may be related to ubiquitination. In summary, NSC-S improved prognosis and ER stress in TBI rats and might be a promising treatment for relieving TBI.

Deciphering molecular heterogeneity and dynamics of human hippocampal neural stem cells at different ages and injury states

While accumulated publications support the existence of neurogenesis in the adult human hippocampus, the homeostasis and developmental potentials of neural stem cells (NSCs) under different contexts remain unclear. Based on our generated single-nucleus atlas of the human hippocampus across neonatal, adult, aging, and injury, we dissected the molecular heterogeneity and transcriptional dynamics of human hippocampal NSCs under different contexts. We further identified new specific neurogenic lineage markers that overcome the lack of specificity found in some well-known markers. Based on developmental trajectory and molecular signatures, we found that a subset of NSCs exhibit quiescent properties after birth, and most NSCs become deep quiescence during aging. Furthermore, certain deep quiescent NSCs are reactivated following stroke injury. Together, our findings provide valuable insights into the development, aging, and reactivation of the human hippocampal NSCs, and help to explain why adult hippocampal neurogenesis is infrequently observed in humans.