Identification Of Stem Cells Research Articles

Histological Identification of Germline Stem Cells’ Recipients for Conservation of Balkan Trout Fish Species by Transplantation Technology

Combining cryopreservation of germline stem cells (GSCs) with their subsequent transplantation into recipient fish is a powerful technique for long-term conservation of the genetic resources of threatened fish species. However, transplantation of GSCs has been limited by a failure to identify an appropriate recipient for surrogate production of donor-derived gametes. In the worst-case scenario, recipients may completely reject the transplanted GSCs due to an immunological reaction. This limitation can be overcome by specifying the gonadal status of both GSC donor and recipient species. This study used histological methods to identify possible GSC recipients for rescuing endangered trout fish species on the Balkan Peninsula. The study specified the gonadal status of brown trout, triploid rainbow trout, and tiger trout. The findings revealed that both triploid rainbow trout and tiger trout are sterile. The fish's testes contained only early-stage germ cells and did not develop past type-B spermatogonia, whereas the ovaries contained only oogonia. Both spermatogenesis and oogenesis were incomplete in these fish, and the gametes, i.e., functional spermatozoa and eggs, could not be formed. As a result, these fish make excellent recipients for GSC transplantation. Because most Balkan trout belong to the genus Salmo and closely related species, tiger trout would be a more feasible recipient of GSCs due to the small phylogenetic distance, as it is a hybrid of brown trout female and brook trout male.

Transient stabilization of human cardiovascular progenitor cells from hPSCs in vitro reflects stage-specific heart development in vivo.

Understanding the molecular identity of human pluripotent stem cell (hPSC)-derived cardiac progenitors and mechanisms controlling their proliferation and differentiation, is valuable for developmental biology and regenerative medicine. Here we show that chemical modulation of Histone Acetyl Transferases (HATs; by IQ-1) and WNT (by CHIR99021), synergistically enable the transient and reversible block of directed cardiac differentiation progression on hPSCs. The resulting stabilized cardiovascular progenitors (SCPs) are characterized by ISL1pos/KI-67pos/NKX2-5neg expression. In the presence of the chemical inhibitors, SCPs maintain a proliferation quiescent state. Upon small molecules removal SCPs resume proliferation and concomitant NKX2-5 upregulation triggers cell-autonomous differentiation into cardiomyocytes. Directed differentiation of SCPs into the endothelial and smooth muscle lineages confirms their full developmental potential typical of bona fide cardiovascular progenitors. Single-cell RNAseq-based transcriptional profiling of our in vitro generated human SCPs notably reflects the dynamic cellular composition of E8.25-E9.25 posterior second heart field (pSHF) of mouse hearts, hallmarked by NR2F2 expression. Investigating molecular mechanisms of SCP stabilization, we found that the cell-autonomously regulated Retinoic Acid (RA) and BMP signaling is governing SCPs transition from quiescence towards proliferation and cell-autonomous differentiation, reminiscent of a niche-like behavior. The chemically defined and reversible nature our stabilization approach provides an unprecedented opportunity to dissect mechanisms of cardiovascular progenitors' specification and reveal their cellular and molecular properties.

WITHDRAWN: Unveiling the future of endodontics: An update on dental pulp regeneration strategies

Pulpal and periapical ailments, prevalent oral afflictions, result from irreversible perturbations to dental pulp caused by potent stimuli such as caries, trauma, or iatrogenic factors. Current treatments include root canal therapy and pulp revascularization, yet achieving complete pulp tissue regeneration remains challenging. Recent advancements in biomaterial science and tissue engineering have shifted focus towards employing diverse methodologies for restoring damaged tooth pulp. These include stem/progenitor cell populations, revascularization techniques, scaffolds, and material-based approaches. Notably, the identification of dental pulp stem cells (DPSCs) has increased interest in stem cell-mediated pulp regeneration. Current research explores cell transplantation and homing strategies. Despite progress, challenges persist in preclinical and clinical applications. This narrative review assesses the current state of regenerative endodontics, emphasizing dental pulp regeneration techniques, including their advantages, drawbacks, and biological aspects such as DPSCs, biomaterials, and growth factors. Challenges and potential solutions are discussed to guide future clinical translation, offering insights for advancing regenerative endodontics.

Alexander Friedenstein, Mesenchymal Stem Cells, Shifting Paradigms and Euphemisms.

Six decades ago, Friedenstein and coworkers published a series of seminal papers identifying a cell population in bone marrow with osteogenic potential, now referred to as mesenchymal stem cells (MSCs). This work was also instrumental in establishing the identity of hematopoietic stem cell and the identification of skeletal stem/progenitor cell (SSPC) populations in various skeletal compartments. In recognition of the centenary year of Friedenstein's birth, I review key aspects of his work and discuss the evolving concept of the MSC and its various euphemisms indorsed by changing paradigms in the field. I also discuss the recent emphasis on MSC stromal quality attributes and how emerging data demonstrating a mechanistic link between stromal and stem/progenitor functions bring renewed relevance to Friedenstein's contributions and much needed unity to the field.

Comparative characteristics of the stem cells’ number in the stromal vascular fraction of infrapatellar fat pad and subcutaneous fat tissue

ObjectivesThe use of infrapatellar fat pad adipose stem cells (IPFP-ASCs) shows an age-independent proliferation and differentiation potential. In addition, the pronounced chondrogenic potential of IPFP-ASCs makes them promising candidates for research for use in other methods of regenerative therapy. The purpose of this study was to ascertain the presence and compare the relative abundance of cells exhibiting an immunohistochemical profile characteristic of adipose-derived mesenchymal stem cells in selected samples of the stromal vascular fraction (SVF) obtained from the IPFP and subcutaneous fat tissue. MethodsA direct immunohistochemical study was carried out in serial paraffin sections of the SVF of the infrapatellar fat pad (IPFP) and subcutaneous tissue, using monoclonal antibodies. The minimum criteria were established by the International Society for Cell Therapy to ensure the identity of mesenchymal stem cells use CD73, CD90, and CD105 as positive markers and CD34, CD31, and CD45 as a negative. ResultsAccording to the results of histological, immunohistochemical, morphometric, and statistical studies, it was found that in the SVF of IPFP and subcutaneous adipose tissue, the relative number of cells with the profile CD105+, CD73+, CD34+, CD31−, CD45− in the standard field of view (×200), the SVF of IPFP was 1.58%, whereas the SVF of subcutaneous adipose tissue was 6.92 %, which was statistically significantly greater by 4.38 times (p ​< ​0.05). ConclusionThe presence of a sufficient number of mesenchymal stromal cells in IPFP in combination with their topographic relationship with the structures of the joint determines the use of the SVF of the IPFP for the treatment of diseases of the knee joint. Level of evidenceIII.

KAT8 beyond Acetylation: A Survey of Its Epigenetic Regulation, Genetic Variability, and Implications for Human Health.

Lysine acetyltransferase 8, also known as KAT8, is an enzyme involved in epigenetic regulation, primarily recognized for its ability to modulate histone acetylation. This review presents an overview of KAT8, emphasizing its biological functions, which impact many cellular processes and range from chromatin remodeling to genetic and epigenetic regulation. In many model systems, KAT8's acetylation of histone H4 lysine 16 (H4K16) is critical for chromatin structure modification, which influences gene expression, cell proliferation, differentiation, and apoptosis. Furthermore, this review summarizes the observed genetic variability within the KAT8 gene, underscoring the implications of various single nucleotide polymorphisms (SNPs) that affect its functional efficacy and are linked to diverse phenotypic outcomes, ranging from metabolic traits to neurological disorders. Advanced insights into the structural biology of KAT8 reveal its interaction with multiprotein assemblies, such as the male-specific lethal (MSL) and non-specific lethal (NSL) complexes, which regulate a wide range of transcriptional activities and developmental functions. Additionally, this review focuses on KAT8's roles in cellular homeostasis, stem cell identity, DNA damage repair, and immune response, highlighting its potential as a therapeutic target. The implications of KAT8 in health and disease, as evidenced by recent studies, affirm its importance in cellular physiology and human pathology.

Neonatal epithelial reparative capacity is enhanced by acellular placental extract in porcine models

Necrotizing enterocolitis (NEC) is a devastating condition with a ~30% mortality rate in pre-term, very low birth-weight infants. Premature infants lack vital in utero ingestion of amniotic fluid which accelerates intestinal maturation and reduces inflammation. Therefore, an acellular placental extract (PE) akin to amniotic fluid may be therapeutic for NEC. The objective of this study was to evaluate PE’s capacity to accelerate repair following or prevent the induction of NEC-like injury. We hypothesized that PE would enhance neonatal porcine intestinal epithelial cells’ capacity to repair in vitro and in vivo. NEC was induced in 12 piglets via pre-term cesarean delivery and hyperosmolar formula feeding. Prior to formula feeding, piglets were nil per os or enterally supplemented with PE. Tissue, collected at euthanasia, up to 72H after formula initiation, was evaluated grossly and histologically and with immunohistochemical staining for proliferation (Ki67), stem cell identity (Sox9), and apoptosis (CC3). Numerical outputs were assessed with Kolmogorov-Smirnov testing. PE’s effect on epithelial restitution was assessed with scratch assays performed on confluent monolayers derived from ~1-day old piglet ileum. Monolayers were pre-treated with either actin polymerization inhibitor, Latrunculin A, or a cell cycle inhibitor, hydroxyurea. After scratch, either media or PE in media was applied. Scratch-closure was monitored for 24H; percentage-closure was calculated and analyzed using 2-way ANOVA and Tukey multiple comparison. Scratch-wound leading-edge cells were examined for EdU and Ki67 immunofluorescent positivity which was evaluated using Kolmogorov-Smirnov analysis. Tight junction recovery was assessed using identically derived confluent monolayers grown on Transwell inserts and exposed to hypoxia (18H, 1%O2, 5%CO2). Following hypoxia, PE or media alone was added to the apical chamber. Transepithelial electrical resistance (TEER) was measured every 6-12H for 48H using a symmetrical disc electrode chamber. TEER rate of change was analyzed using a two-way ANOVA. For all analyses, significance was set at p&lt;0.05. In vivo PE administration resulted in reduced gross and histological NEC damage in treated compared to untreated piglets (p=0.02). Ki67 and Sox9 expression increased (p=0.71; p=0.93) and CC3 expression decreased with PE treatment (p=0.65). Evaluation of these markers in additional animals is pending. In vitro, PE expedited scratch wound closure (p&lt;0.05) and expanded proliferative cell number along scratch edges (EdU/DAPI, p&lt;0.05; Ki67+EdU/DAPI, p&lt;0.01). Other analyses are pending. PE application prevented gross NEC development in vivo and accelerated recovery in vitro. NIH #R44HD100243; #T32562967-39806. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

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

Intestinal Stem Cells Remodel in Response to Acute Notch Inhibition and Paneth Cell Loss

INTRODUCTION: Intestinal epithelial cells are rapidly renewed throughout life by intestinal stem cells (ISCs). ISC function is regulated by niche factors that orchestrate cellular proliferation and differentiation. Of these, Notch signaling is essential for ISC self-renewal and regulates the cell fate choice between absorptive cells (enterocyte) vs secretory (Paneth, goblet, enteroendocrine, and tuft) cells. Yet, the Notch niche is not fully defined. In the mature small intestine, Paneth cells neighbor each ISC and act as Notch niche cells, providing the Notch signal by expressing the Notch ligands DLL1 and DLL4 on their surface. However, studies in mice have shown that ISCs can function in the immature intestine before Paneth cells are formed, and when Paneth cells are depleted in the adult intestine. We previously observed that acute Notch inhibition via the inhibitor dibenzazepine (DBZ) resulted in Paneth cell apoptosis with intact ISCs displaying transient dysfunction. Here, we aimed to define the Notch niche after Paneth cell apoptosis in adult mice and in the developing intestine. We hypothesized that during acute Notch inhibition, ISCs remodel to compensate for Paneth cell loss by activating Notch ligand expression, and that this remodeling mimics the state of immature ISCs prior to Paneth cell emergence. METHODS: We isolated Lgr5+ ISCs by FACS from Lgr5-GFP-CreERT2 mice 24 hours after DBZ or vehicle treatment and performed bulk RNAseq analysis. To define the Notch niche during development, we analyzed postnatal intestines from Notch ligand reporter mice (Dll1-mCherry and Dll4-mCherry) crossed with the ISC reporter mice (Lgr5-GFP-CreERT2). RESULTS: ISCs isolated from Paneth cell-depleted intestines upregulated expression of Notch ligands Dll4 and Dll4 and various secretory cell markers, with expected downregulation of Notch target genes, but no alteration of other stem cell genes. This suggests that after acute Notch inhibition, Lgr5+ ISCs maintain partial stem cell identity while acquiring a signature resembling that of secretory progenitors. In the immature intestine, we showed by immunohistology that sporadic cells expressing secretory cell markers (LYZ, MUC2, and CHGA) localized to the intervillus region and co-stained with Dll1- or Dll4-mCherry+. This suggests that multiple differentiated cell types could provide the Notch signal to immature ISCs. We also observed occasional Lgr5-GFP+ ISCs that were co-positive for Dll1-mCherry, suggesting that immature ISCs can express Notch ligands at homeostasis. Further experimentation will determine whether these Dll1+ ISCs are similar to the remodeled adult ISCs after Paneth cell depletion. CONCLUSIONS: Acute Notch inhibition directly remodels ISCs to express the Notch ligands, Dll1 and Dll4 in the adult intestine. In the immature intestine, multiple secretory cell types appear to comprise the immature Notch niche. This project was funded by NIH R01 DK118023 awarded to Dr. Linda Samuelson. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Redox regulation of meristem quiescence: outside/in.

Quiescence is an essential property of meristematic cells, which restrains the cell cycle while retaining the capacity to divide. This crucial process not only facilitates life-long tissue homeostasis and regenerative capacity but also provides protection against adverse environmental conditions, enabling cells to conserve the proliferative potency while minimizing DNA damage. As a survival attribute, quiescence is inherently regulated by the products of aerobic life, in particular reactive oxygen species (ROS) and the redox (reduction/oxidation) mechanisms that plant have evolved to channel these into pervasive signals. Adaptive responses allow quiescent cells to compensate for reduced oxygen tension (hypoxia) in a reversible manner, while the regulated production of the superoxide anion (O2·-) facilitates cell division and the maintenance of stem cells. Here we discuss the role of ROS and redox reactions in the control of the quiescent state in plant meristems, and how this process is integrated with cellular energy and hormone biochemistry. We consider the pathways that sense and transmit redox signals with a focus on the central significance of redox regulation in the mitochondria and nucleus, which is a major regulator of quiescence in meristems. We discuss recent studies that suggest that ROS are a critical component of the feedback loops that control stem cell identity and fate, and suggest that the ROS/hypoxia interface is an important 'outside/in' positional cue for plant cells, particularly in meristems.

MAB-5/Hox regulates the Q neuroblast transcriptome, including cwn-1/Wnt, to mediate posterior migration in Caenorhabditis elegans.

Neurogenesis involves the precisely coordinated action of genetic programs controlling large-scale neuronal fate specification down to terminal events of neuronal differentiation. The Q neuroblasts in Caenorhabditis elegans, QL on the left and QR on the right, divide, differentiate, and migrate in a similar pattern to produce three neurons each. However, QL on the left migrates posteriorly, and QR on the right migrates anteriorly. The MAB-5/Hox transcription factor is necessary and sufficient for posterior Q lineage migration and is normally expressed only in the QL lineage. To define genes controlled by MAB-5 in the Q cells, fluorescence-activated cell sorting was utilized to isolate populations of Q cells at a time in early L1 larvae when MAB-5 first becomes active. Sorted Q cells from wild-type, mab-5 loss-of-function (lof), and mab-5 gain-of-function (gof) mutants were subject to RNA-seq and differential expression analysis. Genes enriched in Q cells included those involved in cell division, DNA replication, and DNA repair, consist with the neuroblast stem cell identity of the Q cells at this stage. Genes affected by mab-5 included those involved in neurogenesis, neural development, and interaction with the extracellular matrix. cwn-1, which encodes a Wnt signaling molecule, showed a paired response to mab-5 in the Q cells: cwn-1 expression was reduced in mab-5(lof) and increased in mab-5(gof), suggesting that MAB-5 is required for cwn-1 expression in Q cells. MAB-5 is required to prevent anterior migration of the Q lineage while it transcriptionally reprograms the Q lineage for posterior migration. Functional genetic analysis revealed that CWN-1 is required downstream of MAB-5 to inhibit anterior migration of the QL lineage, likely in parallel to EGL-20/Wnt in a noncanonical Wnt pathway. In sum, work here describes a Q cell transcriptome, and a set of genes regulated by MAB-5 in the QL lineage. One of these genes, cwn-1, acts downstream of mab-5 in QL migration, indicating that this gene set includes other genes utilized by MAB-5 to facilitate posterior neuroblast migration.

SRRM2 splicing factor modulates cell fate in early development.

Embryo development is an orchestrated process that relies on tight regulation of gene expression to guide cell differentiation and fate decisions. The Srrm2 splicing factor has recently been implicated in developmental disorders and diseases, but its role in early mammalian development remains unexplored. Here, we show that Srrm2 dosage is critical for maintaining embryonic stem cell pluripotency and cell identity. Srrm2 heterozygosity promotes loss of stemness, characterised by the coexistence of cells expressing naive and formative pluripotency markers, together with extensive changes in gene expression, including genes regulated by serum-response transcription factor (SRF) and differentiation-related genes. Depletion of Srrm2 by RNA interference in embryonic stem cells shows that the earliest effects of Srrm2 heterozygosity are specific alternative splicing events on a small number of genes, followed by expression changes in metabolism and differentiation-related genes. Our findings unveil molecular and cellular roles of Srrm2 in stemness and lineage commitment, shedding light on the roles of splicing regulators in early embryogenesis, developmental diseases and tumorigenesis.

Abstract LB225: Regulation of breast cancer stem cell identity by PLK1 and FOXC2

Abstract One of the main drivers for the drastic reduction in survival rates caused by metastatic breast cancer is attributed to Epithelial-to-Mesenchymal Transition (EMT). During embryonic development and wound healing, EMT plays a vital role and during cancer pathogenesis, cancer cells reactivate this program to gain plasticity, migration, and invasion promoting metastasis. In addition, EMT also plays a crucial role in generating a subpopulation of highly resilient tumor cells known as cancer stem cells (CSCs). Moreover, following conventional treatment, residual tumor cells that remain after treatment tend to exhibit CSC properties. EMT-induced cancer stem cells exhibit heightened plasticity and stemness, significantly fueling the metastatic spread of cancer and enhancing the endurance and adaptability throughout the process of metastasis. Thus, understanding the molecular intricacies governing stem cell properties holds immense potential for developing targeted therapies to target metastasis and the development of resistance to treatments. To further elucidate EMT-induced cancer stem cell generation, our lab has demonstrated that the Polo-like kinase 1 (PLK1), an important G2/M regulator, plays an important role in the generation of CSCs through Forkhead box protein C2 (FOXC2). Most importantly, we have shown that the FOXC2 transcription factor, known to be crucial in embryonic development, now has emerging roles in metastatic cancer progression. FOXC2 is positioned at the center of the complex network of signal transduction pathways and functions downstream of most EMT-inducing transcription factors. FOXC2 is necessary for the acquisition and maintenance of stem cell property. In addition, we found that phosphorylation of FOXC2 by PLK1 stabilizes, and inhibition of PLK1 causes a decrease in FOXC2 and stemness in cancer cells. This led us to hypothesize that EMT-induced CSC generation is driven by the PLK1-FOXC2 axis. By expressing phosphomimetic and non-phosphorylatable FOXC2 mutants in breast cancer cell lines, we show that PLK1 phosphorylation is necessary for gaining stemness and an increase in symmetric self-renewal type of stem cell division. Evidence will be presented as to how we are targeting the PLK1-FOXC2 axis to make tumors sensitive to standard-of-care treatments. Citation Format: Joanna Joyce Maddela, Maria Castaneda, Petra den Hollander, Nick Kuburich, Sendurai Mani. Regulation of breast cancer stem cell identity by PLK1 and FOXC2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB225.

Homeostatic regulation of renewing tissue cell populations via crowding control: stability, robustness and quasi-dedifferentiation

To maintain renewing epithelial tissues in a healthy, homeostatic state, cell divisions and differentiation need to be tightly regulated. Mechanisms of homeostatic regulation often rely on crowding feedback control: cells are able to sense the cell density in their environment, via various molecular and mechanosensing pathways, and respond by adjusting division, differentiation, and cell state transitions appropriately. Here, we determine, via a mathematically rigorous framework, which general conditions for the crowding feedback regulation (i) must be minimally met, and (ii) are sufficient, to allow the maintenance of homeostasis in renewing tissues. We show that those conditions naturally allow for a degree of robustness toward disruption of regulation. Furthermore, intrinsic to this feedback regulation is that stem cell identity is established collectively by the cell population, not by individual cells, which implies the possibility of ‘quasi-dedifferentiation’, in which cells committed to differentiation may reacquire stem cell properties upon depletion of the stem cell pool. These findings can guide future experimental campaigns to identify specific crowding feedback mechanisms.

Abstract 7070: MEK-ERK signaling maintains epidermal proliferation through H2A.Z deposition

Abstract Recent studies have connected dysregulation of H2A.Z deposition to glioblastoma as well as lung, pancreatic, and metastatic breast cancers. The H2AZ1 and H2AZ2 isoforms, collectively known as H2A.Z, are histone variants that regulate gene expression, stem cell identity, and differentiation during development and in homeostatic tissue. Most tumors originate from epithelial tissues. We utilize skin epidermis, an accessible model of epithelial tissue, to understand the regulatory mechanisms controlling proliferation and differentiation. Primary human epidermal keratinocytes retain their abilities to proliferate, differentiate, and stratify in vitro. First, we observed that progenitor keratinocytes express high levels of H2A.Z mRNA and protein, and that H2A.Z levels significantly and progressively decrease during four days of calcium-induced differentiation. Using ChIP-sequencing, we find a significant, genome-wide decrease in H2A.Z chromatin occupancy in differentiated keratinocytes. Therefore, we hypothesized that H2A.Z is critical for progenitor function. Knock down of either H2AZ1 or H2AZ2 significantly impaired keratinocyte proliferation in holoclone assays. Furthermore, H2AZ1 or H2AZ2 knockdown inhibited epidermal stratification in organotypic culture. Canonically, two chromatin remodeling complexes, SRCAP and EP400, deposit H2A.Z into nucleosomes. While both SRCAP and EP400 knockdown diminish keratinocyte proliferation, only SRCAP knockdown decreases H2A.Z deposition in epidermal keratinocytes. Finally, we find that MEK and ERK signaling is required to sustain expression of SRCAP, H2AZ1, and H2AZ2. MEK or ERK inhibition is sufficient to significantly decrease H2A.Z occupancy genome-wide in progenitor keratinocytes. Citation Format: Stephenie Droll, Benny Zhang, Celia Xue, Maxwell Levine, Xiaomin Bao. MEK-ERK signaling maintains epidermal proliferation through H2A.Z deposition [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 7070.

Deep learning-based predictive classification of functional subpopulations of hematopoietic stem cells and multipotent progenitors.

Hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs) play a pivotal role in maintaining lifelong hematopoiesis. The distinction between stem cells and other progenitors, as well as the assessment of their functions, has long been a central focus in stem cell research. In recent years, deep learning has emerged as a powerful tool for cell image analysis and classification/prediction. In this study, we explored the feasibility of employing deep learning techniques to differentiate murine HSCs and MPPs based solely on their morphology, as observed through light microscopy (DIC) images. After rigorous training and validation using extensive image datasets, we successfully developed a three-class classifier, referred to as the LSM model, capable of reliably distinguishing long-term HSCs, short-term HSCs, and MPPs. The LSM model extracts intrinsic morphological features unique to different cell types, irrespective of the methods used for cell identification and isolation, such as surface markers or intracellular GFP markers. Furthermore, employing the same deep learning framework, we created a two-class classifier that effectively discriminates between aged HSCs and young HSCs. This discovery is particularly significant as both cell types share identical surface markers yet serve distinct functions. This classifier holds the potential to offer a novel, rapid, and efficient means of assessing the functional states of HSCs, thus obviating the need for time-consuming transplantation experiments. Our study represents the pioneering use of deep learning to differentiate HSCs and MPPs under steady-state conditions. This novel and robust deep learning-based platform will provide a basis for the future development of a new generation stem cell identification and separation system. It may also provide new insight into the molecular mechanisms underlying stem cell self-renewal.

Temporal transcriptomic dynamics in developing macaque neocortex

Despite intense research on mice, the transcriptional regulation of neocortical neurogenesis remains limited in humans and non-human primates. Cortical development in rhesus macaque is known to recapitulate multiple facets of cortical development in humans, including the complex composition of neural stem cells and the thicker supragranular layer. To characterize temporal shifts in transcriptomic programming responsible for differentiation from stem cells to neurons, we sampled parietal lobes of rhesus macaque at E40, E50, E70, E80, and E90, spanning the full period of prenatal neurogenesis. Single-cell RNA sequencing produced a transcriptomic atlas of developing parietal lobe in rhesus macaque neocortex. Identification of distinct cell types and neural stem cells emerging in different developmental stages revealed a terminally bifurcating trajectory from stem cells to neurons. Notably, deep-layer neurons appear in the early stages of neurogenesis, while upper-layer neurons appear later. While these different lineages show overlap in their differentiation program, cell fates are determined post-mitotically. Trajectories analysis from ventricular radial glia (vRGs) to outer radial glia (oRGs) revealed dynamic gene expression profiles and identified differential activation of BMP, FGF, and WNT signaling pathways between vRGs and oRGs. These results provide a comprehensive overview of the temporal patterns of gene expression leading to different fates of radial glial progenitors during neocortex layer formation.

Identity and nature of neural stem cells in the adult human subventricular zone

The existence of neural stem cells (NSCs) in adult human brain neurogenic regions remains unresolved. To address this, we created a cell atlas of the adult human subventricular zone (SVZ) derived from fresh neurosurgical samples using single-cell transcriptomics. We discovered 2 adult radial glia (RG)-like populations, aRG1 and aRG2. aRG1 shared features with fetal early RG (eRG) and aRG2 were transcriptomically similar to fetal outer RG (oRG). We also captured early neuronal and oligodendrocytic NSC states. We found that the biological programs driven by their transcriptomes support their roles as early lineage NSCs. Finally, we show that these NSCs have the potential to transition between states and along lineage trajectories. These data reveal that multipotent NSCs reside in the adult human SVZ.

Identification and Evaluation of Cancer Stem Cells in Oral Squamous Cell Carcinoma and Oral Epithelial Dysplasia Using NANOG: An Immunohistochemical Study.

Squamous cell carcinoma of the oral cavity may show precursor lesions, termed as potentially malignant disorders, of which leukoplakia is the most frequent one. Oral leukoplakia is a clinical diagnosis for which the histological diagnosis may be either hyperplasia or oral epithelial dysplasia (OED) and sometimes even oral squamous cell carcinoma (OSCC). Cancer stem cells (CSCs), identified in various tumors, are a specific group of cells that exhibit the properties of self-renewal and differentiation. Among the various biomarkers that identify CSCs, the transcription factor NANOG is considered to be a significant one. In this study, we intend to identify and compare the immunohistochemical expression of NANOG in OSCC, OED, and normal oral mucosa. Tissue blocks of OSCC (n=28), OED (n=28), and normal oral mucosa (n=28) were used in this study. Specimens were immunohistochemically analyzed for NANOG expression. The results were statistically analyzed using one-way ANOVA, Games-Howell post hoc, and Student t-test. Statistical Product and Service Solutions (SPSS, version 21; IBM SPSS Statistics for Windows, Armonk, NY) software was used for performing the statistical analysis, and the level of significance was set as 0.05. NANOG expression was higher in OSCC when compared to oral dysplasias and normal oral mucosa, in decreasing order. A significantly higher histo-score and labeling index score were observed in OSCC and oral dysplasias compared to normal oral mucosa (p=<0.001). The expression levels of NANOG were positively correlated with disease progression in OSCC, implicating that NANOG can be used as a surrogate marker of oral oncogenesis and prognosis. Therefore, decoding the molecular mechanisms ofNANOG regulation in the progression of cancer helps in developing new therapeutic strategies for oral cancer.

Isolation, identification and osteogenic capability analysis of mesenchymal stem cells derived from different layers of human maxillary sinus membrane.

To discover the populations of mesenchymal stem cells (MSCs) derived from different layers of human maxillary sinus membrane (hMSM) and evaluate their osteogenic capability. hMSM was isolated into a monolayer using the combined method of physical separation and enzymatic digestion. The localization of MSCs in hMSM was performed by immunohistological staining and other techniques. Lamina propria layer-derived MSCs (LMSCs) and periosteum layer-derived MSCs (PMSCs) from hMSM were expanded using the explant cell culture method and identified by multilineage differentiation assays, colony formation assay, flow cytometry and so on. The biological characteristics of LMSCs and PMSCs were compared using RNA sequencing, reverse transcription and quantitative polymerase chain reaction, immunofluorescence staining, transwell assay, western blotting and so forth. LMSCs and PMSCs from hMSMs were both CD73-, CD90- and CD105-positive, and CD34-, CD45- and HLA-DR-negative. LMSCs and PMSCs were identified as CD171+/CD90+ and CD171-/CD90+, respectively. LMSCs displayed stronger proliferation capability than PMSCs, and PMSCs presented stronger osteogenic differentiation capability than LMSCs. Moreover, PMSCs could recruit and promote osteogenic differentiation of LMSCs. This study identified and isolated two different types of MSCs from hMSMs. Both MSCs served as good potential candidates for bone regeneration.