Integration of Magnetic-Field-Directed Self-Assembly-Based Cell Culture and Biosensing Platform for Improving hPSCs-Derived Neurons and Quantitative Detection of Neurotransmitter

Despite the fact that human neural cell models have played significant roles in both research and cell replacement therapies for neurological diseases, the existing techniques for obtaining neurons from human pluripotent stem cells (hPSCs) are arduous and intricate. Additionally, the evaluation of neuron quality in the natural environment remains deficient. Consequently, we have developed a comprehensive platform utilizing magnetic-field-directed self-assembly (MDSA) of MXenes@Fe3O4 (M/F) nanocomposites. This platform facilitates the cultivation and in situ analysis of differentiated dopaminergic (DA) neurons. Our results showed that the introduction of M/F enhances neurite outgrowth and leads to the development of more intricate ramifications. Moreover, with the increase of magnetic field intensity, neurite outgrowth is further enhanced, and the proportion of differentiated mature neurons from hPSCs increases. This suggests that our platform promotes the maturation of neurons, emphasizing the crucial role of biophysical cues in expediting the differentiation process. The homogenization platform formed by MDSA of M/F nanocomposites exhibits high conductivity, leading to its exceptional performance in the real-time monitoring of the release of dopamine neurotransmitter from hPSC-derived DA neurons. Hence, this platform demonstrates significant potential for monitoring cell quality. In conclusion, our integrated platform, based on MDSA of M/F nanocomposites, offers a reliable and efficient means for the in vitro generation of human neurons with a controllable quality. The as-prepared platform holds potential for enhancing neuronal maturation and ensuring consistent cell quality, showing significant implications for in vitro biological research, disease modeling, and cell replacement therapy.

CRIPTO-based micro-heterogeneity of mouse muscle satellite cells enables adaptive response to regenerative microenvironment

Skeletal muscle repair relies on heterogeneous populations of satellite cells (SCs). The mechanisms that regulate SC homeostasis and state transition during activation are currently unknown. Here, we investigated the emerging role of non-genetic micro-heterogeneity, i.e., intrinsic cell-to-cell variability of a population, in this process. We demonstrate that micro-heterogeneity of the membrane protein CRIPTO in mouse-activated SCs (ASCs) identifies metastable cell states that allow a rapid response of the population to environmental changes. Mechanistically, CRIPTO micro-heterogeneity is generated and maintained through a process of intracellular trafficking coupled with active shedding of CRIPTO from the plasma membrane. Irreversible perturbation of CRIPTO micro-heterogeneity affects the balance of proliferation, self-renewal, and myogenic commitment in ASCs, resulting in increased self-renewal in vivo. Our findings demonstrate that CRIPTO micro-heterogeneity regulates the adaptative response of ASCs to microenvironmental changes, providing insights into the role of intrinsic heterogeneity in preserving stem cell population diversity during tissue repair.

Interspecies control of development during mammalian gastrulation

Gastrulation represents a pivotal phase of development and aberrations during this period can have major consequences, from minor anatomical deviations to severe congenital defects. Animal models are used to study gastrulation, however, there is considerable morphological and molecular diversity of gastrula across mammalian species. Here, we provide an overview of the latest research on interspecies developmental control across mammals. This includes single-cell atlases of several mammalian gastrula which have enabled comparisons of the temporal and molecular dynamics of differentiation. These studies highlight conserved cell differentiation regulators and both absolute and relative differences in differentiation dynamics between species. Recent advances in in vitro culture techniques have facilitated the derivation, maintenance and differentiation of cell lines from a range of species and the creation of multi-species models of gastrulation. Gastruloids are three-dimensional aggregates capable of self-organising and recapitulating aspects of gastrulation. Such models enable species comparisons outside the confines of the embryo. We highlight recent in vitro evidence that differentiation processes such as somitogenesis and neuronal maturation scale with known in vivo differences in developmental tempo across species. This scaling is likely due to intrinsic differences in cell biochemistry. We also highlight several studies which provide examples of cell differentiation dynamics being influenced by extrinsic factors, including culture conditions, chimeric co-culture, and xenotransplantation. These collective studies underscore the complexity of gastrulation across species, highlighting the necessity of additional datasets and studies to decipher the intricate balance between intrinsic cellular programs and extrinsic signals in shaping embryogenesis.

Differentiation of embryonic stem cells into lung-like cells using lung-derived matrix sheets

Various extracellular matrix (ECM) in the lungs regulate tissue development and homeostasis, as well as provide support for cell structures. However, few studies regarding the effects of lung cell differentiation using lung-derived ECM (LM) alone have been reported. The present study investigated the capability of lung-derived matrix sheets (LMSs) to induce lung cell differentiation using mouse embryonic stem (ES) cells. Expressions of lung-related cell markers were significantly upregulated in ES-derived embryoid bodies (EBs) cultured on an LMS for two weeks. Moreover, immunohistochemical analysis of EBs grown on LMSs revealed differentiation of various lung-related cells. These results suggest that an LMS can be used to promote differentiation of stem cells into lung cells.

Protocol for isolating mice skeletal muscle myoblasts and myotubes via differential antibody validation

Isolation of skeletal muscles allows for the exploration of many complex diseases. Here, we present a protocol for isolating mice skeletal muscle myoblasts and myotubes that have been differentiated through antibody validation. We describe steps for collecting and preparing murine skeletal tissue, myoblast cell maintenance, plating, and cell differentiation. We then detail procedures for cell incubation, immunostaining, slide preparation and storage, and imaging for immunofluorescence validation.

Mechanisms of Alveolar Type 2 Epithelial Cell Death During Acute Lung Injury

Diffuse alveolar epithelial cell (AEC) death occurs extensively during acute lung injury (ALI). Due to the limited proliferative capacity of alveolar type 1 epithelial (AT1) cells, the differentiation and regenerative capacity of alveolar type 2 epithelial (AT2) cells are required to restore the barrier function of AECs. However, during lung injury, AT1 cells are particularly susceptible to injury, and ATII cells die in the presence of severe or certain types of injury. This disruption ultimately results in a hindrance to the ability of AT2 cells to proliferate and differentiate into AT1 cells in time to repair the extensively damaged AECs. Therefore, understanding the mechanism of injury death of AT2 cells may be beneficial to reverse the above situation. This article reviews the main death modes of AT2 cells, including apoptosis, necrosis, necroptosis, pyroptosis, autophagic cell death, and ferroptosis. It compares the various forms of death, showing that various cell injury death modes have unique action mechanisms and partially overlapping pathways. Studying the mechanism of AT2 cell death is helpful in screening and analyzing the target pathway of AEC barrier function recovery. It opens up new ideas and strategies for preventing and treating ALI.

Neural tube-associated boundary caps are a major source of mural cells in the skin

In addition to their roles in protecting nerves and increasing conduction velocity, peripheral glia plays key functions in blood vessel development by secreting molecules governing arteries alignment and maturation with nerves. Here, we show in mice that a specific, nerve-attached cell population, derived from boundary caps (BCs), constitutes a major source of mural cells for the developing skin vasculature. Using Cre-based reporter cell tracing and single-cell transcriptomics, we show that BC derivatives migrate into the skin along the nerves, detach from them, and differentiate into pericytes and vascular smooth muscle cells. Genetic ablation of this population affects the organization of the skin vascular network. Our results reveal the heterogeneity and extended potential of the BC population in mice, which gives rise to mural cells, in addition to previously described neurons, Schwann cells, and melanocytes. Finally, our results suggest that mural specification of BC derivatives takes place before their migration along nerves to the mouse skin.

DPPIV+ fibro-adipogenic progenitors form the niche of adult skeletal muscle self-renewing resident macrophages

Adult tissue-resident macrophages (RMs) are either maintained by blood monocytes or through self-renewal. While the presence of a nurturing niche is likely crucial to support the survival and function of self-renewing RMs, evidence regarding its nature is limited. Here, we identify fibro-adipogenic progenitors (FAPs) as the main source of colony-stimulating factor 1 (CSF1) in resting skeletal muscle. Using parabiosis in combination with FAP-deficient transgenic mice (PdgfrαCreERT2 × DTA) or mice lacking FAP-derived CSF1 (PdgfrαCreERT2 × Csf1flox/null), we show that local CSF1 from FAPs is required for the survival of both TIM4- monocyte-derived and TIM4+ self-renewing RMs in adult skeletal muscle. The spatial distribution and number of TIM4+ RMs coincide with those of dipeptidyl peptidase IV (DPPIV)+ FAPs, suggesting their role as CSF1-producing niche cells for self-renewing RMs. This finding identifies opportunities to precisely manipulate the function of self-renewing RMs in situ to further unravel their role in health and disease.

A patterned human primitive heart organoid model generated by pluripotent stem cell self-organization

Pluripotent stem cell-derived organoids can recapitulate significant features of organ development in vitro. We hypothesized that creating human heart organoids by mimicking aspects of in utero gestation (e.g., addition of metabolic and hormonal factors) would lead to higher physiological and anatomical relevance. We find that heart organoids produced using this self-organization-driven developmental induction strategy are remarkably similar transcriptionally and morphologically to age-matched human embryonic hearts. We also show that they recapitulate several aspects of cardiac development, including large atrial and ventricular chambers, proepicardial organ formation, and retinoic acid-mediated anterior-posterior patterning, mimicking the developmental processes found in the post-heart tube stage primitive heart. Moreover, we provide proof-of-concept demonstration of the value of this system for disease modeling by exploring the effects of ondansetron, a drug administered to pregnant women and associated with congenital heart defects. These findings constitute a significant technical advance for synthetic heart development and provide a powerful tool for cardiac disease modeling.

2P-FLIM unveils time-dependent metabolic shifts during osteogenic differentiation with a key role of lactate to fuel osteogenesis via glutaminolysis identified

BACKGROUND

Human mesenchymal stem cells (hMSCs) utilize discrete biosynthetic pathways to self-renew and differentiate into specific cell lineages, with undifferentiated hMSCs harbouring reliance on glycolysis and hMSCs differentiating towards an osteogenic phenotype relying on oxidative phosphorylation as an energy source.

METHODS

In this study, the osteogenic differentiation of hMSCs was assessed and classified over 14 days using a non-invasive live-cell imaging modality-two-photon fluorescence lifetime imaging microscopy (2P-FLIM). This technique images and measures NADH fluorescence from which cellular metabolism is inferred.

RESULTS

During osteogenesis, we observe a higher dependence on oxidative phosphorylation (OxPhos) for cellular energy, concomitant with an increased reliance on anabolic pathways. Guided by these non-invasive observations, we validated this metabolic profile using qPCR and extracellular metabolite analysis and observed a higher reliance on glutaminolysis in the earlier time points of osteogenic differentiation. Based on the results obtained, we sought to promote glutaminolysis further by using lactate, to improve the osteogenic potential of hMSCs. Higher levels of mineral deposition and osteogenic gene expression were achieved when treating hMSCs with lactate, in addition to an upregulation of lactate metabolism and transmembrane cellular lactate transporters. To further clarify the interplay between glutaminolysis and lactate metabolism in osteogenic differentiation, we blocked these pathways using BPTES and α-CHC respectively. A reduction in mineralization was found after treatment with BPTES and α-CHC, demonstrating the reliance of hMSC osteogenesis on glutaminolysis and lactate metabolism.

CONCLUSION

In summary, we demonstrate that the osteogenic differentiation of hMSCs has a temporal metabolic profile and shift that is observed as early as day 3 of cell culture using 2P-FLIM. Furthermore, extracellular lactate is shown as an essential metabolite and metabolic fuel to ensure efficient osteogenic differentiation and as a signalling molecule to promote glutaminolysis. These findings have significant impact in the use of 2P-FLIM to discover potent approaches towards bone tissue engineering in vitro and in vivo by engaging directly with metabolite-driven osteogenesis.

Bidirectional interplay between metabolism and epigenetics in hematopoietic stem cells and leukemia

During the last decades, remarkable progress has been made in further understanding the complex molecular regulatory networks that maintain hematopoietic stem cell (HSC) function. Cellular and organismal metabolisms have been shown to directly instruct epigenetic alterations, and thereby dictate stem cell fate, in the bone marrow. Epigenetic regulatory enzymes are dependent on the availability of metabolites to facilitate DNA- and histone-modifying reactions. The metabolic and epigenetic features of HSCs and their downstream progenitors can be significantly altered by environmental perturbations, dietary habits, and hematological diseases. Therefore, understanding metabolic and epigenetic mechanisms that regulate healthy HSCs can contribute to the discovery of novel metabolic therapeutic targets that specifically eliminate leukemia stem cells while sparing healthy HSCs. Here, we provide an in-depth review of the metabolic and epigenetic interplay regulating hematopoietic stem cell fate. We discuss the influence of metabolic stress stimuli, as well as alterations occurring during leukemic development. Additionally, we highlight recent therapeutic advancements toward eradicating acute myeloid leukemia cells by intervening in metabolic and epigenetic pathways.

Modeling cardiac fibroblast heterogeneity from human pluripotent stem cell-derived epicardial cells

Cardiac fibroblasts play an essential role in the development of the heart and are implicated in disease progression in the context of fibrosis and regeneration. Here, we establish a simple organoid culture platform using human pluripotent stem cell-derived epicardial cells and ventricular cardiomyocytes to study the development, maturation, and heterogeneity of cardiac fibroblasts under normal conditions and following treatment with pathological stimuli. We demonstrate that this system models the early interactions between epicardial cells and cardiomyocytes to generate a population of fibroblasts that recapitulates many aspects of fibroblast behavior in vivo, including changes associated with maturation and in response to pathological stimuli associated with cardiac injury. Using single cell transcriptomics, we show that the hPSC-derived organoid fibroblast population displays a high degree of heterogeneity that approximates the heterogeneity of populations in both the normal and diseased human heart. Additionally, we identify a unique subpopulation of fibroblasts possessing reparative features previously characterized in the hearts of model organisms. Taken together, our system recapitulates many aspects of human cardiac fibroblast specification, development, and maturation, providing a platform to investigate the role of these cells in human cardiovascular development and disease.

Characterization of a new mouse line triggering transient oligodendrocyte progenitor depletion

Oligodendrocyte progenitor cells (OPC) are the main proliferative cells in the healthy adult brain. They produce new myelinating oligodendrocytes to ensure physiological myelin remodeling and regeneration after various pathological insults. Growing evidence suggests that OPC have other functions. Here, we aimed to develop an experimental model that allows the specific ablation of OPC at the adult stage to unravel possible new functions. We generated a transgenic mouse expressing a floxed human diphtheria toxin receptor under the control of the PDGFRa promoter, crossed with an Olig2Cre mouse to limit the recombination to the oligodendrocyte lineage in the central nervous system. We determined a diphtheria toxin dose to substantially decrease OPC density in the cortex and the corpus callosum without triggering side toxicity after a few daily injections. OPC density was normalized 7 days post-treatment, showing high repopulation capacity from few surviving OPC. We took advantage of this strong but transient depletion to show that OPC loss was associated with behavioral impairment, which was restored by OPC recovery, as well as disruption of the excitation/inhibition balance in the sensorimotor cortex, reinforcing the hypothesis of a neuromodulatory role of OPC in the adult brain.

Identifying secreted biomarkers of dopaminergic ventral midbrain progenitor cells

BACKGROUND

Ventral midbrain (VM) dopaminergic progenitor cells derived from human pluripotent stem cells have the potential to replace endogenously lost dopamine neurons and are currently in preclinical and clinical development for treatment of Parkinson's Disease (PD). However, one main challenge in the quality control of the cells is that rostral and caudal VM progenitors are extremely similar transcriptionally though only the caudal VM cells give rise to dopaminergic (DA) neurons with functionality relevant for cell replacement in PD. Therefore, it is critical to develop assays which can rapidly and reliably discriminate rostral from caudal VM cells during clinical manufacturing.

METHODS

We performed shotgun proteomics on cell culture supernatants from rostral and caudal VM progenitor cells to search for novel secreted biomarkers specific to DA progenitors from the caudal VM. Key hits were validated by qRT-PCR and ELISA.

RESULTS

We identified and validated novel secreted markers enriched in caudal VM progenitor cultures (CPE, LGI1 and PDGFC), and found these markers to correlate strongly with the expression of EN1, which is a predictive marker for successful graft outcome in DA cell transplantation products. Other markers (CNTN2 and CORIN) were found to conversely be enriched in the non-dopaminergic rostral VM cultures. Key novel ELISA markers were further validated on supernatant samples from GMP-manufactured caudal VM batches.

CONCLUSION

As a non-invasive in-process quality control test for predicting correctly patterned batches of caudal VM DA cells during clinical manufacturing, we propose a dual ELISA panel measuring LGI1/CORIN ratios around day 16 of differentiation.

The neuronal nitric oxide synthase expression increases during satellite cell-derived primary myoblasts differentiation

The neuronal nitric oxide synthase (nNOS; encoded by NOS1)-derived nitric oxide (NO) plays an important role in maintaining skeletal muscle mass. In adult skeletal muscle, nNOS localizes to the cell membrane, cytosol, and nucleus, and regulates muscle hypertrophy and atrophy in various subcellular fractions. However, its role in muscle stem cells (also known as muscle satellite cells), which provide myonuclei for postnatal muscle growth, maintenance, and regeneration, remains unclear. The present study aimed to determine nNOS expression in muscle satellite cell-derived primary myoblasts during differentiation and its DNA methylation levels, an epigenetic modification that controls gene expression. Undifferentiated and differentiated satellite cell-derived primary myoblasts were found to express nNOS. Immunohistochemical analysis revealed that nNOS colocalized with Pax7 (satellite cell marker) only in the undifferentiated myoblasts. Furthermore, nNOS immunoreactivity spread to the cytosol of Pax7-negative differentiated myotube-like cells. The level of Nos1µ mRNA, the main isoform of skeletal muscle nNOS, was increased in differentiated satellite cell-derived primary myoblasts compared to that in the undifferentiated cells. However, Nos1 methylation levels remained unchanged during differentiation. These findings suggest that nNOS induction and the appropriate transition of its subcellular localization may contribute to muscle differentiation.

Homeostasis, injury, and recovery dynamics at multiple scales in a self-organizing mouse intestinal crypt

The maintenance of the functional integrity of the intestinal epithelium requires a tight coordination between cell production, migration, and shedding along the crypt-villus axis. Dysregulation of these processes may result in loss of the intestinal barrier and disease. With the aim of generating a more complete and integrated understanding of how the epithelium maintains homeostasis and recovers after injury, we have built a multi-scale agent-based model (ABM) of the mouse intestinal epithelium. We demonstrate that stable, self-organizing behaviour in the crypt emerges from the dynamic interaction of multiple signalling pathways, such as Wnt, Notch, BMP, ZNRF3/RNF43, and YAP-Hippo pathways, which regulate proliferation and differentiation, respond to environmental mechanical cues, form feedback mechanisms, and modulate the dynamics of the cell cycle protein network. The model recapitulates the crypt phenotype reported after persistent stem cell ablation and after the inhibition of the CDK1 cycle protein. Moreover, we simulated 5-fluorouracil (5-FU)-induced toxicity at multiple scales starting from DNA and RNA damage, which disrupts the cell cycle, cell signalling, proliferation, differentiation, and migration and leads to loss of barrier integrity. During recovery, our in silico crypt regenerates its structure in a self-organizing, dynamic fashion driven by dedifferentiation and enhanced by negative feedback loops. Thus, the model enables the simulation of xenobiotic-, in particular chemotherapy-, induced mechanisms of intestinal toxicity and epithelial recovery. Overall, we present a systems model able to simulate the disruption of molecular events and its impact across multiple levels of epithelial organization and demonstrate its application to epithelial research and drug development.

Norepinephrine regulates calcium signals and fate of oligodendrocyte precursor cells in the mouse cerebral cortex

Oligodendrocyte precursor cells (OPCs) generate oligodendrocytes, contributing to myelination and myelin repair. OPCs contact axons and respond to neuronal activity, but how the information relayed by the neuronal activity translates into OPC Ca2+ signals, which in turn influence their fate, remains unknown. We generated transgenic mice for concomitant monitoring of OPCs Ca2+ signals and cell fate using 2-photon microscopy in the somatosensory cortex of awake-behaving mice. Ca2+ signals in OPCs mainly occur within processes and confine to Ca2+ microdomains. A subpopulation of OPCs enhances Ca2+ transients while mice engaged in exploratory locomotion. We found that OPCs responsive to locomotion preferentially differentiate into oligodendrocytes, and locomotion-non-responsive OPCs divide. Norepinephrine mediates locomotion-evoked Ca2+ increases in OPCs by activating α1 adrenergic receptors, and chemogenetic activation of OPCs or noradrenergic neurons promotes OPC differentiation. Hence, we uncovered that for fate decisions OPCs integrate Ca2+ signals, and norepinephrine is a potent regulator of OPC fate.

Stem Cells Derived from Human Exfoliated Deciduous Teeth Functional Assessment: Exploring the Changes of Free Fatty Acids Composition during Cultivation

The metabolic regulation of stemness is widely recognized as a crucial factor in determining the fate of stem cells. When transferred to a stimulating and nutrient-rich environment, mesenchymal stem cells (MSCs) undergo rapid proliferation, accompanied by a change in protein expression and a significant reconfiguration of central energy metabolism. This metabolic shift, from quiescence to metabolically active cells, can lead to an increase in the proportion of senescent cells and limit their regenerative potential. In this study, MSCs from human exfoliated deciduous teeth (SHEDs) were isolated and expanded in vitro for up to 10 passages. Immunophenotypic analysis, growth kinetics, in vitro plasticity, fatty acid content, and autophagic capacity were assessed throughout cultivation to evaluate the functional characteristics of SHEDs. Our findings revealed that SHEDs exhibit distinctive patterns of cell surface marker expression, possess high self-renewal capacity, and have a unique potential for neurogenic differentiation. Aged SHEDs exhibited lower proliferation rates, reduced potential for chondrogenic and osteogenic differentiation, an increasing capacity for adipogenic differentiation, and decreased autophagic potential. Prolonged cultivation of SHEDs resulted in changes in fatty acid composition, signaling a transition from anti-inflammatory to proinflammatory pathways. This underscores the intricate connection between metabolic regulation, stemness, and aging, crucial for optimizing therapeutic applications.

Mechanisms of lineage specification in Caenorhabditis elegans

The studies of cell fate and lineage specification are fundamental to our understanding of the development of multicellular organisms. Caenorhabditis elegans has been one of the premiere systems for studying cell fate specification mechanisms at single cell resolution, due to its transparent nature, the invariant cell lineage, and fixed number of somatic cells. We discuss the general themes and regulatory mechanisms that have emerged from these studies, with a focus on somatic lineages and cell fates. We next review the key factors and pathways that regulate the specification of discrete cells and lineages during embryogenesis and postembryonic development; we focus on transcription factors and include numerous lineage diagrams that depict the expression of key factors that specify embryonic founder cells and postembryonic blast cells, and the diverse somatic cell fates they generate. We end by discussing some future perspectives in cell and lineage specification.

Enhanced production of mesencephalic dopaminergic neurons from lineage-restricted human undifferentiated stem cells

Current differentiation protocols for generating mesencephalic dopaminergic (mesDA) neurons from human pluripotent stem cells result in grafts containing only a small proportion of mesDA neurons when transplanted in vivo. In this study, we develop lineage-restricted undifferentiated stem cells (LR-USCs) from pluripotent stem cells, which enhances their potential for differentiating into caudal midbrain floor plate progenitors and mesDA neurons. Using a ventral midbrain protocol, 69% of LR-USCs become bona fide caudal midbrain floor plate progenitors, compared to only 25% of human embryonic stem cells (hESCs). Importantly, LR-USCs generate significantly more mesDA neurons under midbrain and hindbrain conditions in vitro and in vivo. We demonstrate that midbrain-patterned LR-USC progenitors transplanted into 6-hydroxydopamine-lesioned rats restore function in a clinically relevant non-pharmacological behavioral test, whereas midbrain-patterned hESC-derived progenitors do not. This strategy demonstrates how lineage restriction can prevent the development of undesirable lineages and enhance the conditions necessary for mesDA neuron generation.

Long non-coding RNA (lncRNA) MALAT1 in regulating osteogenic and adipogenic differentiation using a double-stranded gapmer locked nucleic acid nanobiosensor

Long non-coding RNAs (lncRNA) are non-protein coding RNA molecules that are longer than 200 nucleotides. The lncRNA molecule plays diverse roles in gene regulation, chromatin remodeling, and cellular processes, influencing various biological pathways. However, probing the complex dynamics of lncRNA in live cells is a challenging task. In this study, a double-stranded gapmer locked nucleic acid (ds-GapM-LNA) nanobiosensor is designed for visualizing the abundance and expression of lncRNA in live human bone-marrow-derived mesenchymal stem cells (hMSCs). The sensitivity, specificity, and stability were characterized. The results showed that this ds-GapM-LNA nanobiosensor has very good sensitivity, specificity, and stability, which allows for dissecting the regulatory roles of cellular processes during dynamic physiological events. By incorporating this nanobiosensor in living hMSC imaging, we elucidated lncRNA MALAT1 expression dynamics during osteogenic and adipogenic differentiation. The data reveal that lncRNA MALAT1 expression is correlated with distinct sub-stages of osteogenic and adipogenic differentiation.

Human Dental Pulp Stem Cells Are Subjected to Metabolic Reprogramming and Repressed Proliferation and Migration by the Sympathetic Nervous System via α1B-Adrenergic Receptor

INTRODUCTION

Human dental pulp stem cells (hDPSCs) reside in specialized microenvironments in the dental pulp, termed "niches," which are composed of diverse cellular components including nerves. Sensory nerves can positively regulate the expansion and differentiation of pulp cells, while the biological effects of the sympathetic nervous system (SNS) on hDPSCs remain elusive. This study is devoted to investigating the effects and underlying mechanisms of the SNS on the proliferation and migration of hDPSCs.

METHODS

The distribution of sympathetic nerve fibers in human dental pulp was examined by immunofluorescence staining of tyrosine hydroxylase. The concentration of norepinephrine in healthy and carious human dental pulp tissues was detected using enzyme-linked immunosorbent assay. RNA-sequencing was applied to identify the dominant sympathetic neurotransmitter receptor in hDPSCs. Seahorse metabolic assay, adenosine triphosphate assay, lactate assay, and mitochondrial DNA copy number were performed to determine the level of glycometabolism. Transwell assay, wound healing assay, 5-ethynyl-2'-deoxyuridine staining assay, cell cycle assay, and Cell Counting Kit-8 assay were conducted to analyze the migratory and proliferative capacities of hDPSCs.

RESULTS

Sprouting of sympathetic nerve fibers and an increased concentration of norepinephrine were observed in inflammatory pulp tissues. Sympathetic nerve fibers were mainly distributed along blood vessels, and aldehyde dehydrogenase 1-positive hDPSCs resided in close proximity to neurovascular bundles. ADRA1B was identified as the major sympathetic neurotransmitter receptor expressed in hDPSCs, and its expression was enhanced in inflammatory pulp tissues. In addition, the SNS inhibited the proliferation and migration of hDPSCs through metabolic reprogramming via ADRA1B and its crosstalk with serine-threonine kinase and p38 mitogen-activated protein kinase signaling pathways.

CONCLUSIONS

This study demonstrates that the SNS can shift the metabolism of hDPSCs from oxidative phosphorylation to anaerobic glycolysis via ADRA1B and its crosstalk with serine-threonine kinase and p38 mitogen-activated protein kinase signaling pathways, thereby inhibiting the proliferative and migratory abilities of hDPSCs. This metabolic shift may facilitate the maintenance of the quiescent state of hDPSCs.

Development of accessible platforms to promote myofibroblast differentiation by playing on hydrogel scaffold composition

Mechanomimetic materials are particularly attractive for modeling in vitro fibroblast to myofibroblast (Myof) transition, a key process in the physiological repair of damaged tissue, and recognized as the core cellular mechanism of pathological fibrosis in different organs. In vivo, mechanical stimuli from the extracellular matrix (ECM) are crucial, together with cell-cell contacts and the pro-fibrotic transforming growth factor (TGF)-β1, in promoting fibroblast differentiation. Here, we explore the impact of hydrogels made by polyacrylamide with different composition on fibroblast behavior. By appropriate modulation of the hydrogel composition (e.g. adjusting the crosslinker content), we produce and fully characterize three kinds of scaffolds with different Young modulus (E). We observe that soft hydrogels (E < 1 kPa) induced fibroblast differentiation better than stiffer ones, also in the absence of TGF-β1. This study provides a readily accessible biomaterial platform to promote Myof generation. The easy approach used and the commercial availability of the monomers make these hydrogels suitable to a wide range of biomedical applications combined with high reproducibility and simple preparation protocols.

Gingival mesenchymal stem cell therapy, immune cells, and immunoinflammatory application

MSC-based therapeutic strategies have proven to be incredibly effective. Robust self-renewal, multilineage differentiation, and potential for tissue regeneration and disease treatments are all features of MSCs isolated from oral tissue. Human exfoliated deciduous teeth, dental follicles, dental pulp, apical papilla SCs, and alveolar bone are the primary sources of oral MSC production. The early immunoinflammatory response is the first stage of the healing process. Oral MSCs can interact with various cells, such as immune cells, revealing potential immunomodulatory regulators. They also have strong differentiation and regeneration potential. Therefore, a ground-breaking strategy would be to research novel immunomodulatory approaches for treating disease and tissue regeneration that depend on the immunomodulatory activities of oral MSCs during tissue regeneration.

Leukemia inhibitory factor shortens primary cilia by upregulating C-C motif chemokine 2 in human neural stem/progenitor cells

Primary cilia on neural stem/progenitor cells (NSPCs) play an important role in determining cell fate, although the regulatory mechanisms involved in the ciliogenesis remain largely unknown. In this study, we analyzed the effect of the leukemia inhibitory factor (LIF) for the primary cilia in immortalized human NSPCs. LIF withdrawal elongated the primary cilia length, whereas the addition of LIF shortened it. Microarray gene expression analysis revealed that differentially expressed genes (DEGs) associated with LIF treatment were related with the multiple cytokine signaling pathways. Among the DEGs, C-C motif chemokine 2 (CCL2) had the highest ranking and its increase in the protein concentration in the NSPCs-conditioned medium after the LIF treatment was confirmed by ELISA. Interestingly, we found that CCL2 was a negative regulator of cilium length, and LIF-induced shortening of primary cilia was antagonized by CCL2-specific antibody, suggesting that LIF could influence cilia length via upregulating CCL2. The shortening effect of LIF and CCL2 on primary cilia was also observed in SH-SY5Y cells. The results of the study suggested that the LIF-CCL2 axis may well be a regulator of NSPCs and its primary cilia length, which could affect multiple cellular processes, including NSPC proliferation and differentiation.

Exosomal microRNA-223 from neutrophil-like cells inhibits osteogenic differentiation of PDLSCs through the cGMP-PKG signaling pathway

BACKGROUND AND OBJECTIVE

Neutrophils-derived exosomes have been shown to cause tissue inflammation in many diseases, but their role in periodontitis, a neutrophil-mediated disease, is unknown. Here, we investigated the effect of neutrophil-like cells derived exosomes on osteogenic dysfunction of periodontal ligament stem cells (PDLSCs) in periodontitis.

METHODS

Neutrophil-like cells were derived from HL-60 cells by dimethylsulfoxide stimulation. Exosomes were isolated by ultracentrifugation and characterized using transmission electron microscopy, nanoflow cytometry and western blot. MicroRNA-223 (miR-223) expression were analyzed by real-time PCR. Western blot, alkaline phosphatase (ALP), and alizarin red staining were conducted to assess whether exosomes could affect the osteogenic differentiation of PDLSCs. The expression of miR-223 was inhibited in PDLSCs by transfecting with miR-223 inhibitor. Cyclic guanosine monophosphate (cGMP) expression was determined by enzyme-linked immunosorbent assay.

RESULTS

We found that miR-223 was significantly increased in neutrophils and neutrophil-like cells derived exosomes. Treatment with exosomes derived from neutrophil-like cells upregulated miR-223 expression and inhibited the osteogenic differentiation of PDLSCs, while transfection with miR-223 inhibitor significantly promoted PDLSCs osteogenic differentiation. In addition, co-treatment with KT5823, a cGMP-PKG pathway inhibitor, markedly abrogated the rescue effects of miR-223 inhibitor on the osteogenic differentiation of PDLSCs.

CONCLUSIONS

Our findings suggest that neutrophil-like cells derived exosomes might inhibit osteogenic differentiation of PDLSCs by transporting miR-223 and regulating the cGMP-PKG signaling pathway.

Body fluid-derived stem cells - an untapped stem cell source in genitourinary regeneration

Somatic stem cells have been obtained from solid organs and tissues, including the bone marrow, placenta, corneal stroma, periosteum, adipose tissue, dental pulp and skeletal muscle. These solid tissue-derived stem cells are often used for tissue repair, disease modelling and new drug development. In the past two decades, stem cells have also been identified in various body fluids, including urine, peripheral blood, umbilical cord blood, amniotic fluid, synovial fluid, breastmilk and menstrual blood. These body fluid-derived stem cells (BFSCs) have stemness properties comparable to those of other adult stem cells and, similarly to tissue-derived stem cells, show cell surface markers, multi-differentiation potential and immunomodulatory effects. However, BFSCs are more easily accessible through non-invasive or minimally invasive approaches than solid tissue-derived stem cells and can be isolated without enzymatic tissue digestion. Additionally, BFSCs have shown good versatility in repairing genitourinary abnormalities in preclinical models through direct differentiation or paracrine mechanisms such as pro-angiogenic, anti-apoptotic, antifibrotic, anti-oxidant and anti-inflammatory effects. However, optimization of protocols is needed to improve the efficacy and safety of BFSC therapy before therapeutic translation.

Hypoxia dissociates HDAC6/FOXO1 complex and aggregates them into nucleus to regulate autophagy and osteogenic differentiation

OBJECTIVE

This research aimed to elucidate the molecular mechanisms underlying the periodontitis-associated bone loss, with particular emphasis on the contributory role of hypoxic microenvironment in this process.

BACKGROUND

Periodontitis generally causes alveolar bone loss and is often associated with a hypoxic microenvironment, which affects bone homeostasis. However, the regulating mechanism between hypoxia and jaw metabolism remains unclear. Hypoxia triggers autophagy, which is closely related to osteogenic differentiation, but how hypoxia-induced autophagy regulates bone metabolism is unknown. HDAC6 and FOXO1 are closely related to bone metabolism and autophagy, respectively, but whether they are related to hypoxia-induced bone loss and their internal mechanisms is still unclear.

METHODS

Established rat nasal obstruction model and hypoxia cell model. Immunohistochemistry was performed to detect the expression and localization of HDAC6 and FOXO1 proteins, analysis of autophagic flux and transmission electron microscopy was used to examine the autophagy level and observe the autophagosomes, co-immunoprecipitation and chromatin immunoprecipitation were preformed to investigate the interaction of HDAC6 and FOXO1.

RESULTS

Hypoxia causes increased autophagy and reduced osteogenic differentiation in rat mandibles and BMSCs, and blocking autophagy can attenuate hypoxia-induced osteogenic differentiation decrease. Moreover, hypoxia dissociated the FOXO1-HDAC6 complex and accumulated them in the nucleus. Knocking down of FOXO1 or HDAC6 alleviated hypoxia-induced autophagy elevation or osteogenic differentiation reduction by binding to related genes, respectively.

CONCLUSION

Hypoxia causes mandibular bone loss and autophagy elevation. Mechanically, hypoxia dissociates the FOXO1-HDAC6 complex and aggregates them in the nucleus, whereas HDAC6 decreases osteogenic differentiation and FOXO1 enhances autophagy to inhibit osteogenic differentiation.

Molecular mechanisms of cellular metabolic homeostasis in stem cells

Many tissues and organ systems have intrinsic regeneration capabilities that are largely driven and maintained by tissue-resident stem cell populations. In recent years, growing evidence has demonstrated that cellular metabolic homeostasis plays a central role in mediating stem cell fate, tissue regeneration, and homeostasis. Thus, a thorough understanding of the mechanisms that regulate metabolic homeostasis in stem cells may contribute to our knowledge on how tissue homeostasis is maintained and provide novel insights for disease management. In this review, we summarize the known relationship between the regulation of metabolic homeostasis and molecular pathways in stem cells. We also discuss potential targets of metabolic homeostasis in disease therapy and describe the current limitations and future directions in the development of these novel therapeutic targets.

The emerging roles of deep crypt secretory cells in colonic physiology

Deep crypt secretory (DCS) cells are a population of epithelial cells located at the colonic crypt base that share some similarities to Paneth and goblet cells. They were initially defined as c-Kit expressing cells, though subsequent work showed that they are more specifically marked by Reg4 in the murine colon. The best-understood function of DCS cells at present is supporting the stem cell niche by generating Notch and EGF ligands. However, as these cells also express immunoregulatory (e.g., Ccl6) and host defense (e.g., Retnlb) genes, it is likely they have additional functions in maintaining colonic health outside of maintenance of the stem niche. Recent advances in single-cell transcriptomic profiling hint at additional epithelial and immune roles that may exist for these cells and have aided in elucidating their developmental lineage. This review highlights the emerging evidence supporting a crucial role for DCS cells in intestinal physiology, the current understanding of how these cells are regulated, and their potential role(s) in colonic disease.

The Origin and Fate of Chondrocytes: Cell Plasticity in Physiological Setting

PURPOSE OF REVIEW

Here, we discuss the origin of chondrocytes, their destiny, and their plasticity in relationship to bone growth, articulation, and formation of the trabeculae. We also consider these processes from a biological, clinical, and evolutionary perspective.

RECENT FINDINGS

Chondrocytes, which provide the template for the formation of most bones, are responsible for skeletal growth and articulation during postnatal life. In recent years our understanding of the fate of these cells has changed dramatically. Current evidence indicates a paradoxical situation during skeletogenesis, with some cells of mesenchymal condensation differentiating directly into osteoblasts, whereas others of the same kind give rise to highly similar osteoblasts via a complex process of differentiation involving several chondrocyte intermediates. The situation becomes even more paradoxical during postnatal growth when stem cells in the growth plate produce differentiated, functional progenies, which thereafter presumably dedifferentiate into another type of stem cell. Such a remarkable transition from one cell type to another under postnatal physiological conditions provides a fascinating example of cellular plasticity that may have valuable clinical implications.

Prostate lineage-specific metabolism governs luminal differentiation and response to antiandrogen treatment

Lineage transitions are a central feature of prostate development, tumourigenesis and treatment resistance. While epigenetic changes are well known to drive prostate lineage transitions, it remains unclear how upstream metabolic signalling contributes to the regulation of prostate epithelial identity. To fill this gap, we developed an approach to perform metabolomics on primary prostate epithelial cells. Using this approach, we discovered that the basal and luminal cells of the prostate exhibit distinct metabolomes and nutrient utilization patterns. Furthermore, basal-to-luminal differentiation is accompanied by increased pyruvate oxidation. We establish the mitochondrial pyruvate carrier and subsequent lactate accumulation as regulators of prostate luminal identity. Inhibition of the mitochondrial pyruvate carrier or supplementation with exogenous lactate results in large-scale chromatin remodelling, influencing both lineage-specific transcription factors and response to antiandrogen treatment. These results establish reciprocal regulation of metabolism and prostate epithelial lineage identity.

The multifaceted role of mitochondria in HSC fate decisions: energy and beyond

Hematopoietic stem cells (HSCs) have the properties to self-renew and/or differentiate into all-mature blood cell lineages. The fate decisions to generate progeny that retain stemness properties or that commit to differentiation is a fundamental process to maintain tissue homeostasis and must be tightly regulated to prevent HSC overgrowth or exhaustion. HSC fate decisions are inherently coupled to cell division. The transition from quiescence to activation is accompanied by major metabolic and mitochondrial changes that are important for cell cycle entry and for balanced decisions between self-renewal and differentiation. In this review, we discuss the current understanding of the role of mitochondrial metabolism in HSC transition from quiescence to activation and fate decisions.

JAM-C Is Important for Lens Epithelial Cell Proliferation and Lens Fiber Maturation in Murine Lens Development

Purpose

The underlying mechanism of congenital cataracts caused by deficiency or mutation of junctional adhesion molecule C (JAM-C) gene remains unclear. Our study aims to elucidate the abnormal developmental process in Jamc-/- lenses and reveal the genes related to lens development that JAM-C may regulate.

Methods

Jamc knockout (Jamc-/-) mouse embryos and pups were generated for in vivo studies. Four key developmental stages from embryonic day (E) 12.5 to postnatal day (P) 0.5 were selected for the following experiments. Hematoxylin and eosin staining was used for histological analysis. The 5-bromo-2'-deoxyuridine (BrdU) incorporation assay and TUNEL staining were performed to label lens epithelial cell (LEC) proliferation and apoptosis, respectively. Immunofluorescence and Western blot were used to analyze the markers of lens epithelium, cell cycle exit, and lens fiber differentiation.

Results

JAM-C was expressed throughout the process of lens development. Deletion of Jamc resulted in decreased lens size and disorganized lens fibers, which arose from E16.5 and aggravated gradually. The LECs of Jamc-/- lenses showed decreased quantity and proliferation, accompanied with reduction of key transcription factor, FOXE3. The fibers in Jamc-/- lenses were disorganized. Moreover, Jamc-deficient lens fibers showed significantly altered distribution patterns of Cx46 and Cx50. The marker of fiber homeostasis, γ-crystallin, was also decreased in the inner cortex and core fibers of Jamc-/- lenses.

Conclusions

Deletion of JAM-C exhibits malfunction of LEC proliferation and fiber maturation during murine lens development, which may be related to the downregulation of FOXE3 expression and abnormal localization patterns of Cx46 and Cx50.

Bipolar disorder-iPSC derived neural progenitor cells exhibit dysregulation of store-operated Ca2+ entry and accelerated differentiation

While most of the efforts to uncover mechanisms contributing to bipolar disorder (BD) focused on phenotypes at the mature neuron stage, little research has considered events that may occur during earlier timepoints of neurodevelopment. Further, although aberrant calcium (Ca2+) signaling has been implicated in the etiology of this condition, the possible contribution of store-operated Ca2+ entry (SOCE) is not well understood. Here, we report Ca2+ and developmental dysregulations related to SOCE in BD patient induced pluripotent stem cell (iPSC)-derived neural progenitor cells (BD-NPCs) and cortical-like glutamatergic neurons. First, using a Ca2+ re-addition assay we found that BD-NPCs and neurons had attenuated SOCE. Intrigued by this finding, we then performed RNA-sequencing and uncovered a unique transcriptome profile in BD-NPCs suggesting accelerated neurodifferentiation. Consistent with these results, we measured a slower rate of proliferation, increased neurite outgrowth, and decreased size in neurosphere formations with BD-NPCs. Also, we observed decreased subventricular areas in developing BD cerebral organoids. Finally, BD NPCs demonstrated high expression of the let-7 family while BD neurons had increased miR-34a, both being microRNAs previously implicated in neurodevelopmental deviations and BD etiology. In summary, we present evidence supporting an accelerated transition towards the neuronal stage in BD-NPCs that may be indicative of early pathophysiological features of the disorder.

Tumor cell-released kynurenine biases MEP differentiation into megakaryocytes in individuals with cancer by activating AhR-RUNX1

Tumor-derived factors are thought to regulate thrombocytosis and erythrocytopenia in individuals with cancer; however, such factors have not yet been identified. Here we show that tumor cell-released kynurenine (Kyn) biases megakaryocytic-erythroid progenitor cell (MEP) differentiation into megakaryocytes in individuals with cancer by activating the aryl hydrocarbon receptor-Runt-related transcription factor 1 (AhR-RUNX1) axis. During tumor growth, large amounts of Kyn from tumor cells are released into the periphery, where they are taken up by MEPs via the transporter SLC7A8. In the cytosol, Kyn binds to and activates AhR, leading to its translocation into the nucleus where AhR transactivates RUNX1, thus regulating MEP differentiation into megakaryocytes. In addition, activated AhR upregulates SLC7A8 in MEPs to induce positive feedback. Importantly, Kyn-AhR-RUNX1-regulated MEP differentiation was demonstrated in both humanized mice and individuals with cancer, providing potential strategies for the prevention of thrombocytosis and erythrocytopenia.

[Relationship between Notch signaling pathway and mitochondrial energy metabolism]

Notch signaling pathway is a highly conserved signaling pathway in the process of evolution. It is composed of three parts: Notch receptor, ligand and effector molecules responsible for intracellular signal transduction. It plays an important role in cell proliferation, differentiation, development, migration, apoptosis and other processes, and has a regulatory effect on tissue homeostasis and homeostasis. Mitochondria are the sites of oxidative metabolism in eukaryotes, where sugars, fats and proteins are finally oxidized to release energy. In recent years, the regulation of Notch signaling pathway on mitochondrial energy metabolism has attracted more and more attention. A large number of data have shown that Notch signaling pathway has a significant effect on mitochondrial energy metabolism, but the relationship between Notch signaling pathway and mitochondrial energy metabolism needs to be specifically and systematically discussed. In this paper, the relationship between Notch signaling pathway and mitochondrial energy metabolism is reviewed, in order to improve the understanding of them and provide new ideas for the treatment of related diseases.

Schizophyllan promotes osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells in vitro

BACKGROUND

Bioactive polysaccharides are a promising way for bone disease prevention with high efficiency. Schizophyllan (SPG) is a polysaccharide derived from a species of fungus with anticancer, antitumor, and anti-inflammatory effects. In the present study, for the first time, the cell proliferation, osteogenic markers, mineral deposition, and osteogenic gene expression of human adipose tissue-derived mesenchymal stem cells (hADMSCs) grown on SPG were evaluated by in vitro assays.

METHODS AND RESULTS

The cytotoxicity of SPG was measured using the MTT assay and acridine orange staining. Differentiation of hADMSCs was assessed using alkaline phosphatase (ALP) activity test, cellular calcium content assay, and mineralized matrix staining. To this end, Alizarin red S, von Kossa staining, and the expression of bone-specific markers, including ALP, Runx2, and osteonectin, were used by real-time RT-PCR over a 2-week period. According to the results, SPG at 10 µg/ml concentration was determined as the optimal dosage for differentiation studies. The results of osteogenic differentiation tests showed that compared to the control groups in vitro, SPG enhanced the osteogenic markers and mineralization as well as upregulation of the expression of bone specific genes in differentiated hADMSCs during differentiation.

CONCLUSIONS

The results revealed that SPG could be applied as effective factor for osteogenic differentiation in the future. The current study provides insights into the hADMSC-based treatment and introduces promising therapeutic material for individuals who suffer from bone defects and injuries.

CREB1 alleviates the apoptosis and potentiates the osteogenic differentiation of zoledronic acid-treated human periodontal ligament stem cells via up-regulating VEGF

Periodontitis represents a severe inflammatory illness in tooth supporting tissue. It has been supported that cAMP response element binding protein 1 (CREB1), a common transcription factor, extensively participates in osteogenic differentiation. Here, the current study was to look into the impacts of CREB1 on the process of periodontitis and its possible action mechanism. After human periodontal ligament stem cells (PDLSCs) were challenged with zoledronic acid (ZA), CREB1 expression was examined with RT-qPCR and western blotting. CCK-8 assay appraised cell activity. Following CREB1 elevation or/and vascular endothelial growth factor (VEGF) silencing in ZA-treated PDLSCs, CCK-8 and TUNEL assays separately estimated cell viability and apoptosis. Western blotting tested the expression of apoptosis- and osteogenic differentiation-associated proteins. ALP staining measured PDLSCs osteogenic ability and ARS staining estimated mineralized nodule formation. JASPAR predicted the potential binding of CREB1 with VEGF promoter, which was then testified by ChIP and luciferase reporter assays. RT-qPCR and western blotting tested VEGF expression. CREB1 expression was declined in ZA-exposed PDLSCs and CREB1 elevation exacerbated the viability and osteogenic differentiation while obstructed the apoptosis of PDLSCs. Additionally, CREB1 bond to VEGF promoter and transcriptionally activated VEGF expression. Further, VEGF absence partially stimulated the apoptosis while suppressed the osteogenic differentiation of CREB1-overexpressing PDLSCs treated by ZA. To be concluded, CREB1 might activate VEGF transcription to obstruct the apoptosis while contribute to the osteogenic differentiation of ZA-treated PDLSCs.

Reproducible Differentiation of Human Pluripotent Stem Cells into Two-Dimensional Cortical Neuron Cultures with Checkpoints for Success

The patterning of excitatory cortical neurons from human pluripotent stem cells (hPSCs) is a desired technique for the study of neurodevelopmental disorders, as neurons can be created and compared from control hPSC lines, hPSC lines generated from patients, and CRISPR-modified hPSC lines. Therefore, this technique allows for the examination of disease phenotypes and assists in the development of potential new therapeutics for neurodevelopmental disorders. Many protocols, however, are optimized for use with specific hPSC lines or within a single laboratory, and they often provide insufficient guidance on how to identify positive stages in the differentiation or how to troubleshoot. Here, we present an efficient and reproducible directed differentiation protocol to generate two-dimensional cultures of hPSC-derived excitatory cortical neurons without intermediary embryoid body formation. This novel protocol is supported by our data generated with five independent hPSC lines and in two independent laboratories. Importantly, as neuronal differentiations follow a long time course to reach maturity, we provide extensive guidance regarding morphological and flow cytometry checkpoints allowing for early indications of successful differentiation. We also include extensive troubleshooting tips and support protocols to assist the operator. The goal of this protocol is to assist others in the successful differentiation of excitatory cortical neurons from hPSCs. © 2023 Wiley Periodicals LLC. Basic Protocol: Directed differentiation of hPSCs into excitatory cortical neurons Support Protocol 1: Harvesting and fixing cells for flow cytometry analyses Support Protocol 2: Performing flow cytometry analyses Support Protocol 3: Thawing NPCs from a cryopreserved stock Alternate Protocol 1: Continuing Expansion of NPCs Alternate Protocol 2: Treatment of neurons with Ara-C to ablate radial glia Support Protocol 4: Experimental methods for validation of excitatory cortical neurons.

A Novel Magnetic Manipulation Promotes Directional Growth of Periodontal Ligament Stem Cells

Periodontium is the rally of soft and hard tissues, which will be devastated continuously by the compromise of periodontitis. Current periodontal therapeutic methods cannot effectively reconstruct periodontal ligament (PDL), which is oriented at an angle with tooth root and combined hard tissues to form cementum-PDL-alveolar bone complex. Hence, it is urgent to find new techniques for PDL reconstruction to achieve functional regeneration of periodontium. Herein, we developed a novel method to manipulate the distribution and growth of periodontal ligament stem cells (PDLSCs) by utilizing highly paralleled static magnetic field (SMF) and magnetic nanoparticles (MNPs). PDLSCs were incubated with MNPs in vitro to label with them. Meanwhile, CCK8 and live/dead cell staining assay were used to detect the impact of SMF and MNPs on cell viability. The directional migration and growth of PDLSCs were visualized under microscope. Furthermore, real-time quantitative PCR and western blot were utilized to calculate the expression level of PDL-related genes. The results showed that PDLSCs could rapidly take up MNPs without compromising cell proliferation and viability, consequently endowed with the ability to respond via magnetic force. The cell migration analysis indicated that PDLSCs could move along the magnetic induction line, testifying that SMF exerted forces on PDLSCs that labeled with MNPs. It was demonstrated that collective application of SMF and MNPs not only induced PDLSCs organized and grew directionally, but also initiated elongation of cells and nucleus. Furthermore, the morphological alteration of the nucleus could also effectively enhance the gene and protein expression of Collagen Ⅰα2, Collagen Ⅲ, and Periostin, suggesting the capability of PDLSCs to differentiate into PDL. In conclusion, this study exhibits a new approach for directional reconstruction of PDL to obtain physiological and functional regeneration of periodontium. The Clinical Trial Registration number: WCHSIRB-D-2022-458.

Induced differentiation of primordial germ cell like cells from SOX9+ porcine skin derived stem cells

Understanding the mechanisms behind porcine primordial germ cell like cells (pPGCLCs) development, differentiation, and gametogenesis is crucial in the treatment of infertility. In this study, SOX9+ skin derived stem cells (SOX9+ SDSCs) were isolated from fetal porcine skin and a high-purity SOX9+ SDSCs population was obtained. The SOX9+ SDSCs were induced to transdifferentiate into PGCLCs during 8 days of cultured. The results of RNA-seq, western blot and immunofluorescence staining verified SDSCs have the potential to transdifferentiate into PGCLCs from aspects of transcription factor activation, germ layer differentiation, energy metabolism, and epigenetic changes. Both adherent and suspended cells were collected. The adherent cells were found to be very similar to early porcine primordial germ cells (pPGCs). The suspended cells resembled late stage pPGCs and had a potential to enter meiotic process. This SDSCs culture-induced in vitro model is expected to provide suitable donor cells for stem cell transplantation in the future.

Transcription Factor Id1 Plays an Essential Role in Th9 Cell Differentiation by Inhibiting Tcf3 and Tcf4

T helper type 9 (Th9) cells play important roles in immune responses by producing interleukin-9 (IL-9). Several transcription factors are responsible for Th9 cell differentiation; however, transcriptional regulation of Th9 cells is not fully understood. Here, it is shown that Id1 is an essential transcriptional regulator of Th9 cell differentiation. Id1 is induced by IL-4 and TGF-β. Id1-deficient naïve CD4 T cells fail to differentiate into Th9 cells, and overexpression of Id1 induce expression of IL-9. Mass spectrometry analysis reveals that Id1 interacts with Tcf3 and Tcf4 in Th9 cells. In addition, RNA-sequencing, chromatin immunoprecipitation, and transient reporter assay reveal that Tcf3 and Tcf4 bind to the promoter region of the Il9 gene to suppress its expression, and that Id1 inhibits their function, leading to Th9 differentiation. Finally, Id1-deficient Th9 cells ameliorate airway inflammation in an animal model of asthma. Thus, Id1 is a transcription factor that plays an essential role in Th9 cell differentiation by inhibiting Tcf3 and Tcf4.

Functional brain region-specific neural spheroids for modeling neurological diseases and therapeutics screening

3D spheroids have emerged as powerful drug discovery tools given their high-throughput screening (HTS) compatibility. Here, we describe a method for generating functional neural spheroids by cell-aggregation of differentiated human induced pluripotent stem cell (hiPSC)-derived neurons and astrocytes at cell type compositions mimicking specific regions of the human brain. Recordings of intracellular calcium oscillations were used as functional assays, and the utility of this spheroids system was shown through disease modeling, drug testing, and formation of assembloids to model neurocircuitry. As a proof of concept, we generated spheroids incorporating neurons with Alzheimer's disease-associated alleles, as well as opioid use disorder modeling spheroids induced by chronic treatment of a mu-opioid receptor agonist. We reversed baseline functional deficits in each pilot disease model with clinically approved treatments and showed that assembloid activity can be chemogenetically manipulated. Here, we lay the groundwork for brain region-specific neural spheroids as a robust functional assay platform for HTS studies.

Disruptions in cell fate decisions and transformed enteroendocrine cells drive intestinal tumorigenesis in Drosophila

Most epithelial tissues are maintained by stem cells that produce the different cell lineages required for proper tissue function. Constant communication between different cell types ensures precise regulation of stem cell behavior and cell fate decisions. These cell-cell interactions are often disrupted during tumorigenesis, but mechanisms by which they are co-opted to support tumor growth in different genetic contexts are poorly understood. Here, we introduce PromoterSwitch, a genetic platform we established to generate large, transformed clones derived from individual adult Drosophila intestinal stem/progenitor cells. We show that cancer-driving genetic alterations representing common colon tumor genome landscapes disrupt cell fate decisions within transformed tissue and result in the emergence of abnormal cell fates. We also show that transformed enteroendocrine cells, a differentiated, hormone-secreting cell lineage, support tumor growth by regulating intestinal stem cell proliferation through multiple genotype-dependent mechanisms, which represent potential vulnerabilities that could be exploited for therapy.

Latest progress in low-intensity pulsed ultrasound for studying exosomes derived from stem/progenitor cells

Stem cells have self-renewal, replication, and multidirectional differentiation potential, while progenitor cells are undifferentiated, pluripotent or specialized stem cells. Stem/progenitor cells secrete various factors, such as cytokines, exosomes, non-coding RNAs, and proteins, and have a wide range of applications in regenerative medicine. However, therapies based on stem cells and their secreted exosomes present limitations, such as insufficient source materials, mature differentiation, and low transplantation success rates, and methods addressing these problems are urgently required. Ultrasound is gaining increasing attention as an emerging technology. Low-intensity pulsed ultrasound (LIPUS) has mechanical, thermal, and cavitation effects and produces vibrational stimuli that can lead to a series of biochemical changes in organs, tissues, and cells, such as the release of extracellular bodies, cytokines, and other signals. These changes can alter the cellular microenvironment and affect biological behaviors, such as cell differentiation and proliferation. Here, we discuss the effects of LIPUS on the biological functions of stem/progenitor cells, exosomes, and non-coding RNAs, alterations involved in related pathways, various emerging applications, and future perspectives. We review the roles and mechanisms of LIPUS in stem/progenitor cells and exosomes with the aim of providing a deeper understanding of LIPUS and promoting research and development in this field.

Scleral remodeling in early adulthood: the role of FGF-2

Emmetropization, a natural process of ocular elongation, is closely associated with scleral remodeling. The Fibroblast growth factor-2 (FGF-2) was reported involved in scleral remodeling in myopia models. Herein, we aimed to investigate the role of scleral fibroblast-to-myofibroblast differentiation and FGF-2 in scleral remodeling during maturation. Our findings revealed that the posterior scleral fibroblasts (SFs) from mature guinea pigs exhibit increased stiffness compared to those from young guinea pigs. Moreover, mature SFs displayed decreased cell proliferation but increased levels of α-SMA, matrix metalloproteinase 2 (MMP2), and collagen 1, when compared to young SFs. Additionally, the mRNA expression of scleral Fgf-2, Fgf receptor 1 (Fgfr1), Fgfr2, Fgfr3, and Fgfr4 was increased in mature SFs. Notably, exogenous FGF-2 showed increased cell proliferation and led to decreased expression of α-SMA, MMP2, and collagen 1 in mature SFs. Overall, our findings highlight the influence of maturation on SFs from posterior scleral shells, resulting in increased stiffness and the manifestation of fibroblast-to-myofibroblast differentiation during development. Exogenous FGF-2 increased cell proliferation and reversed the age-related fibroblast-to-myofibroblast differentiation, suggesting a potential role of FGF-2 in regulating scleral remodeling.

"Small Hepatocytes" in the Liver

Mature hepatocytes (MHs) in an adult rodent liver are categorized into the following three subpopulations based on their proliferative capability: type I cells (MH-I), which are committed progenitor cells that possess a high growth capability and basal hepatocytic functions; type II cells (MH-II), which possess a limited proliferative capability; and type III cells (MH-III), which lose the ability to divide (replicative senescence) and reach the final differentiated state. These subpopulations may explain the liver's development and growth after birth. Generally, small-sized hepatocytes emerge in mammal livers. The cells are characterized by being morphologically identical to hepatocytes except for their size, which is substantially smaller than that of ordinary MHs. We initially discovered small hepatocytes (SHs) in the primary culture of rat hepatocytes. We believe that SHs are derived from MH-I and play a role as hepatocytic progenitors to supply MHs. The population of MH-I (SHs) is distributed in the whole lobules, a part of which possesses a self-renewal capability, and decreases with age. Conversely, injured livers of experimental models and clinical cases showed the emergence of SHs. Studies demonstrate the involvement of SHs in liver regeneration. SHs that appeared in the injured livers are not a pure population but a mixture of two distinct origins, MH-derived and hepatic-stem-cell-derived cells. The predominant cell-derived SHs depend on the proliferative capability of the remaining MHs after the injury. This review will focus on the SHs that appeared in the liver and discuss the significance of SHs in liver regeneration.

BMP9 is a potent inducer of chondrogenesis, volumetric expansion and collagen type II accumulation in bovine auricular cartilage chondroprogenitors

Reconstruction of the outer ear currently requires harvesting of cartilage from the posterior of the auricle or ribs leading to pain and donor site morbidity. An alternative source for auricular reconstruction is in vitro tissue engineered cartilage using stem/progenitor cells. Several candidate cell-types have been studied with tissue-specific auricular cartilage progenitor cells (AuCPC) of particular interest. Whilst chondrogenic differentiation of competent stem cells using growth factor TGFβ1 produces cartilage this tissue is frequently fibrocartilaginous and lacks the morphological features of hyaline cartilage. Recent work has shown that growth factor BMP9 is a potent chondrogenic and morphogenetic factor for articular cartilage progenitor cells, and we hypothesised that this property extends to cartilage-derived progenitors from other tissues. In this study we show monoclonal populations of AuCPCs from immature and mature bovine cartilage cultured with BMP9 produced cartilage pellets have 3-5-fold greater surface area in sections than those grown with TGFβ1. Increased volumetric growth using BMP9 was due to greater sGAG deposition in immature pellets and significantly greater collagen accumulation in both immature and mature progenitor pellets. Polarised light microscopy and immunohistochemical analyses revealed that the organisation of collagen fibrils within pellets is an important factor in the growth of pellets. Additionally, chondrocytes in BMP9 stimulated cell pellets had larger lacunae and were more evenly dispersed throughout the extracellular matrix. Interestingly, BMP9 tended to normalise the response of immature AuCPC monoclonal cell lines to differentiation cues whereas cells exhibited more variation under TGFβ1. In conclusion, BMP9 appears to be a potent inducer of chondrogenesis and volumetric growth for AuCPCs a property that can be exploited for tissue engineering strategies for reconstructive surgery though with the caveat of negligible elastin production following 21-day treatment with either growth factor.