Human induced pluripotent stem cells: From cell origin, genomic stability and epigenetic memory to translational medicine

Exosomes in stroke management: A promising paradigm shift in stroke therapy

Effective treatment methods for stroke, a common cerebrovascular disease with a high mortality rate, are still being sought. Exosome therapy, a form of acellular therapy, has demonstrated promising efficacy in various diseases in animal models; however, there is currently insufficient evidence to guide the clinical application of exosome in patients with stroke. This article reviews the progress of exosome applications in stroke treatment. It aims to elucidate the significant potential value of exosomes in stroke therapy and provide a reference for their clinical translation. At present, many studies on exosome-based therapies for stroke are actively underway. Regarding preclinical research, exosomes, as bioactive substances with diverse sources, currently favor stem cells as their origin. Due to their high plasticity, exosomes can be effectively modified through various physical, chemical, and genetic engineering methods to enhance their efficacy. In animal models of stroke, exosome therapy can reduce neuroinflammatory responses, alleviate oxidative stress damage, and inhibit programmed cell death. Additionally, exosomes can promote angiogenesis, repair and regenerate damaged white matter fiber bundles, and facilitate the migration and differentiation of neural stem cells, aiding the repair process. We also summarize new directions for the application of exosomes, specifically the exosome intervention through the ventricular-meningeal lymphatic system. The review findings suggest that the treatment paradigm for stroke is poised for transformation.

Recent therapeutic advances in the treatment and management of amyotrophic lateral sclerosis: the era of regenerative medicine

INTRODUCTION

Despite decades of research, effective disease-modifying treatments for Amyotrophic Lateral Sclerosis (ALS) remain scarce. The emergence of regenerative medicine presents a new frontier for ALS treatment.

AREAS COVERED

This review is based on a comprehensive literature search using PubMed, Scopus and clinical trials databases on the recent therapeutic advancements in ALS, giving focus to regenerative medicine. The article includes coverage of stem cell-based therapies, including mesenchymal, neural and induced pluripotent stem cells; all of which may offer potential neuroprotective and immunomodulatory effects. Gene therapy, particularly antisense oligonucleotides targeting ALS-related mutations, has gained traction, with tofersen becoming the first FDA-approved genetic therapy for ALS. The article also covers emerging approaches such as extracellular vesicles, immune-modulating therapies, and bioengineering techniques, including CRISPR-based gene editing and cellular reprogramming, that hold promise for altering disease progression.

EXPERT OPINION

While regenerative medicine provides hope for ALS patients, significant challenges remain. Biomarkers will play a crucial role in guiding personalized treatment strategies, ensuring targeted interventions. Future research should prioritize optimizing combinatory approaches, integrating different therapy strategies to maximize patient outcomes. Although regenerative medicine is still in its early clinical stages, its integration into ALS treatment paradigms could redefine disease management and alter its natural course.

The advancements in precision medicine for Leber congenital amaurosis: Breakthroughs from genetic diagnosis to therapy

Leber congenital amaurosis (LCA) is a hereditary retinal disease, typically manifesting as severe vision impairment in infancy. With the advancement of precision medicine, genetic diagnosis and targeted therapies offer new hope for LCA patients, significantly improving both diagnostic accuracy and therapeutic efficacy. We summarize the epidemiological characteristics, clinical manifestations, and molecular genetics underlying LCA. It also highlights recent developments in precision treatment strategies, including gene replacement therapy, CRISPR/Cas9-mediated gene editing, and antisense oligonucleotide therapies. In addition, we discuss the applications of induced pluripotent stem cells and retinal organoids in LCA treatment research. Furthermore, we explore preventive strategies and future treatment directions for LCA, including the development of novel gene therapy vectors, the optimization of combinatorial treatment strategies, and the formulation of personalized treatment approaches. These advancements hold significant potential to offer improved treatment options and enhance the quality of life for LCA patients.

Urine-derived stem cells: a sustainable resource for advancing personalized medicine and dental regeneration

Urine-based therapy, an ancient practice, has been utilized across numerous civilizations to address a wide range of ailments. Urine was considered a priceless resource in numerous traditional therapeutic applications due to its reported medicinal capabilities. While the utilization of urine treatment is contentious and lacks significant support from modern healthcare, the discovery of urine-derived stem cells (UDSCs) has introduced a promising avenue for cell-based therapy. UDSCs offer a noninvasive and easily repeatable collection method, making them a practical and viable option for therapeutic applications. Research has shown that UDSCs contribute to organ preservation by promoting revascularization and decreasing inflammatory reactions in many diseases and conditions. This review will outline the contemporary status of UDSCs research and explore their potential applications in both fundamental science and medical practice.

Revitalizing the Epigenome of Adult Jaw Periosteal Cells: Enhancing Diversity in iPSC-Derived Mesenchymal Stem Cells (iMSCs)

Induced pluripotent stem cells (iPSCs) are rapidly emerging as a transformative resource in regenerative medicine. In a previous study, our laboratory achieved a significant milestone by successfully reprograming jaw periosteal cells (JPCs) into iPSCs, which were then differentiated into iPSC-derived mesenchymal stem cells (iMSCs). Using an optimized protocol, we generated iMSCs with a remarkable osteogenic potential while exhibiting lower expression levels of the senescence markers p16 and p21 compared to the original JPCs. This study aimed to explore the epigenetic landscape by comparing the DNA methylation and transcription profiles of iMSCs with their JPC precursors, seeking to uncover key differences. Additionally, this analysis provided an opportunity for us to investigate the potential rejuvenation effects associated with cellular reprogramming. To assess the safety of the generated cells, we evaluated their ability to form teratomas through subcutaneous injection into immunodeficient mice. Our findings revealed that, while the methylation profile of iMSCs closely mirrored that of JPCs, distinct iMSC-specific methylation patterns were evident. Strikingly, the application of DNA methylation (DNAm) clocks for biological age estimation showed a dramatic reduction in DNAm age to approximately zero in iPSCs-a rejuvenation effect that persisted in the derived iMSCs. This profound reset in biological age, together with our transcriptome data, indicate that iMSCs could possess an enhanced regenerative potential compared to adult MSCs. Future in vivo studies should validate this hypothesis.

MiR-122-5p inhibits the epithelial mesenchymal transition of liver cancer cells by inducing hiPSCs to differentiate into hepatocyte-like cells

Epithelial-mesenchymal transition (EMT) is closely linked to liver cancer prognosis, invasiveness, and aggressiveness. One promising treatment for liver cancer is cell therapy, where stem cells are stimulated to develop into functional liver cells. This study aimed to investigate the effect of miR-122-5p on the differentiation of human induced pluripotent stem cells (hiPSCs) into hepatocyte-like cells and its impact on the EMT process in liver cancer cells. MiR-122-5p was overexpressed or silenced in hiPSCs to analyze the expression of liver-specific markers, including AFP, ALB and ASGPR, to confirm hepatocyte-like differentiation. A co-culture system with HepG2 liver cancer cells was also used to evaluate the effect of miR-122-5p-overexpressing hiPSCs or miR-122-5p-silencing hiPSCs on the expression of EMT markers. Results revealed that overexpression of miR-122-5p in hiPSCs induced hepatocyte-like characteristics, as evidenced by increased levels of AFP, ALB, and ASGPR. However, knockdown of miR-122-5p had the opposite effect. In the co-culture system, hiPSCs overexpressing miR-122-5p inhibited the EMT process of HepG2 cells, resulting in increased levels of mesenchymal markers and decreased levels of epithelial markers. Taken together, miR-122-5p promotes the differentiation of hiPSCs into hepatocyte-like cells and inhibits EMT process of liver cancer cells. Targeting miR-122-5p may be a novel approach to prevent liver cancer progression through cell therapy.

A Living Organoid Biobank of Crohn's Disease Patients Reveals Distinct Clinical Correlates of Molecular Subtypes of Disease

Current clinical decision-making lacks reliable preclinical models to predict patient outcomes. Here, we establish patient-derived organoids (PDOs) as predictive tools in Crohn's disease (CD), a complex, heterogeneous disorder. Using a living biobank of adult stem cell-derived colonic-PDOs, we identified two molecular CD subtypes-Immune-Deficient Infectious CD ( IDICD ) and Stress and Senescence-Induced Fibrostenotic CD ( S2FCD )-each with distinct genomic, transcriptomic and functional profiles, along with paired therapeutics. By prospectively linking colonic PDO-derived phenotypes to real-world patient outcomes, we uncovered that while S2FCD associates with severe colonic disease, IDICD associates with severe ileal disease, prior ileocecal surgery, and future disease progression. This approach transforms PDOs from static descriptive models into dynamic tools that capture the past, present, and future of disease behavior and reveals their utility as patient-specific predictive platforms, extending their use beyond oncology to complex inflammatory diseases. Findings also suggest that colonic immune dysfunction may drive ileal-CD, independent of colonic involvement.

GRAPHICAL ABSTRACT

In Brief

In this work, Penrose et al. demonstrate the potential of patient-derived organoids (PDOs) as predictive tools in Crohn's disease (CD) that capture the past, present, and future of disease behavior, thereby advancing PDO-informed precision medicine beyond oncology into complex inflammatory diseases.

HIGHLIGHTS

A living PDO biobank identified two molecular CD subtypes with distinct functional phenotypes.PDO subtyping tracked severity of ileal disease, prior surgery and future disease progression.Colonic immune dysfunction may drive ileal-CD, independent of colonic involvement.Colonic CD-PDOs are dynamic platforms for outcome-deterministic therapeutic testing.

Cell Reprogramming, Transdifferentiation, and Dedifferentiation Approaches for Heart Repair

Cardiovascular disease (CVD) remains the leading cause of death globally, with myocardial infarction (MI) being a major contributor. The current therapeutic approaches are limited in effectively regenerating damaged cardiac tissue. Up-to-date strategies for heart regeneration/reconstitution aim at cardiac remodeling through repairing the damaged tissue with an external cell source or by stimulating the existing cells to proliferate and repopulate the compromised area. Cell reprogramming is addressed to this challenge as a promising solution, converting fibroblasts and other cell types into functional cardiomyocytes, either by reverting cells to a pluripotent state or by directly switching cell lineage. Several strategies such as gene editing and the application of miRNA and small molecules have been explored for their potential to enhance cardiac regeneration. Those strategies take advantage of cell plasticity by introducing reprogramming factors that regress cell maturity in vitro, allowing for their later differentiation and thus endorsing cell transplantation, or promote in situ cell proliferation, leveraged by scaffolds embedded with pro-regenerative factors promoting efficient heart restoration. Despite notable advancements, important challenges persist, including low reprogramming efficiency, cell maturation limitations, and safety concerns in clinical applications. Nonetheless, integrating these innovative approaches offers a promising alternative for restoring cardiac function and reducing the dependency on full heart transplants.

Metabolic and Mitochondrial Dysregulations in Diabetic Cardiac Complications

The growing prevalence of diabetes highlights the urgent need to study diabetic cardiovascular complications, specifically diabetic cardiomyopathy, which is a diabetes-induced myocardial dysfunction independent of hypertension or coronary artery disease. This review examines the role of mitochondrial dysfunction in promoting diabetic cardiac dysfunction and highlights metabolic mechanisms such as hyperglycaemia-induced oxidative stress. Chronic hyperglycaemia and insulin resistance can activate harmful pathways, including advanced glycation end-products (AGEs), protein kinase C (PKC) and hexosamine signalling, uncontrolled reactive oxygen species (ROS) production and mishandling of Ca2+ transient. These processes lead to cardiomyocyte apoptosis, fibrosis and contractile dysfunction. Moreover, endoplasmic reticulum (ER) stress and dysregulated RNA-binding proteins (RBPs) and extracellular vesicles (EVs) contribute to tissue damage, which drives cardiac function towards heart failure (HF). Advanced patient-derived induced pluripotent stem cell (iPSC) cardiac organoids (iPS-COs) are transformative tools for modelling diabetic cardiomyopathy and capturing human disease's genetic, epigenetic and metabolic hallmarks. iPS-COs may facilitate the precise examination of molecular pathways and therapeutic interventions. Future research directions encourage the integration of advanced models with mechanistic techniques to promote novel therapeutic strategies.

Monitoring Autophagy in Human Aging: Key Cell Models and Insights

Autophagy, a key cellular degradation and recycling pathway, is critical for maintaining cellular homeostasis and responding to metabolic and environmental stress. Evidence for age-related autophagic dysfunction and its implications in chronic age-related diseases including neurodegeneration is accumulating. However, as a complex, multi-step process, autophagy can be challenging to measure, particularly in humans and human aging- and disease-relevant models. This review describes the links between macroautophagy, aging, and chronic age-related diseases. We present three novel human cell models, peripheral blood mononuclear cells (PBMCs), primary dermal fibroblasts (PDFs), and induced neurons (iNs), which serve as essential tools for studying autophagy flux and assessing its potential as a biomarker for aging. Unlike traditional models, these cell models retain age- and disease-associated molecular signatures, enhancing their relevance for human studies. The development of robust tools and methodologies for measuring autophagy flux in human cell models holds promise for advancing our understanding of autophagy's role in aging and age-related diseases, ultimately facilitating the discovery of therapies to enhance health outcomes.

Efficient Differentiation of hiPSCs into hMSC-like Cells under Chemically Defined Conditions on Temperature-Sensitive Micropatterned Surfaces

The fairness of long-term self-renewal and robust cell proliferation limits the applications of human mesenchymal stem cells (hMSCs) in regenerative medicine. Inducing hMSCs from human-induced pluripotent stem cells (hiPSCs), which have the advantages of autogenous and no cell number issues, is highly valuable. However, current induction methods using FBS-containing mesenchymal culture medium have problems, including immunogenicity, microbial contamination, and low efficiency. To solve these problems, we propose a chemically defined induction protocol incorporating transforming growth factor-beta 1 and retinoic acid (RA) additives in serum-free E6 medium for the suspension induction of embryoid bodies in hiPSCs. Additionally, microgroove-patterned polydimethylsiloxane surfaces coated with temperature-sensitive N-isopropylacrylamide (PNIPAAm) were prepared for efficient harvesting and purification of induced hiPSC-derived hMSCs (hiPSC-MSCs). The results showed that both supplementation with RA and patterned microgrooves with a width of 20 μm could accelerate the induction of hiPSC-MSCs, realizing the promising scalable production of homogeneous cells. This study successfully established a chemically defined induction protocol and utilized patterned surfaces to obtain clinically applicable hiPSC-MSCs, which show great promise in tissue engineering, gene therapy, and cell transplantation.

Prospects of induced pluripotent stem cells in treating advancing Alzheimer's disease: A review

The World Health Organization has identified Alzheimer's disease (AD), the leading cause of dementia globally, as a public health priority. However, the complex multifactorial pathology of AD means that its etiology remains incompletely understood. Despite being recognized a century ago, incomplete knowledge has hindered the development of effective treatments for AD. Recent scientific advancements, particularly in induced pluripotent stem cell (iPSC) technology, show great promise in elucidating the fundamental mechanisms of AD. iPSCs play a dual role in regenerating damaged cells for therapeutic purposes and creating disease models to understand AD pathology and aid in drug screening. Nevertheless, as an emerging field, iPSC technology requires further technological advancement to develop effective AD treatments in the future. Thus, this review summarizes recent advances in stem cell therapies, specifically iPSCs, aimed at understanding AD pathology and developing treatments.

Generation of Retinal Ganglion Cells from Reprogrammed Keratocytes of Non-Glaucoma and Glaucoma Donors

Human induced pluripotent stem cell (hiPSC)-based disease modeling can be successfully recapitulated to mimic disease characteristics across various human pathologies. Glaucoma, a progressive optic neuropathy, primarily affects the retinal ganglion cells (RGCs). While multiple groups have successfully generated RGCs from non-diseased hiPSCs, producing RGCs from glaucomatous human samples holds significant promise for understanding disease pathology by revealing patient-specific disease signatures. Given that keratocytes originate from the neural crest and previous reports suggest that ocular fibroblasts from glaucomatous donors carry pathogenic signatures, it is highly plausible that these signatures imprinted within the keratocytes will also be present in the derived RGCs. Thus, we aimed to generate RGCs from both glaucomatous and non-glaucomatous donor keratocytes and validate disease-specific signatures in 3D retinal organoids and in isolated RGCs. Our protocol describes the generation of iPSCs from keratocytes of both glaucomatous and non-glaucomatous donors, followed by their differentiation into retinal organoids. Subsequent isolation and culturing of RGCs were performed. Disease signatures in the RGCs were validated in both 3D retinal organoids (ROs) and 2D RGC cultures, and glaucomatous RGCs in 3D and 2D cultures demonstrated increased cleaved CASP3 and significant RGC loss, indicating disease imprints in the hiPSC-derived RGCs. This model offers a venue and high throughput platform for studying glaucomatous disease pathology and holds significant potential for drug discovery using RGCs derived from human donors. © 2025 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Culturing of keratocytes from human cadaveric donors Basic Protocol 2: Reprogramming donor keratocytes into iPSCs Basic Protocol 3: Evaluation of chromosomal loss during reprogramming in iPSCs by karyotyping Basic Protocol 4: Generation of 3D ROs Basic Protocol 5: Dissociation and culturing of RGCs from 3D ROs Support Protocol 1: Immunostaining for phenotypic characterization of cells Support Protocol 2: Sectioning of 3D ROs and immunostaining Support Protocol 3: Western blotting for cleaved CASP3 and THY1.

Modeling of skeletal development and diseases using human pluripotent stem cells

Human skeletal elements are formed from distinct origins at distinct positions of the embryo. For example, the neural crest produces the facial bones, the paraxial mesoderm produces the axial skeleton, and the lateral plate mesoderm produces the appendicular skeleton. During skeletal development, different combinations of signaling pathways are coordinated from distinct origins during the sequential developmental stages. Models for human skeletal development have been established using human pluripotent stem cells (hPSCs) and by exploiting our understanding of skeletal development. Stepwise protocols for generating skeletal cells from different origins have been designed to mimic developmental trails. Recently, organoid methods have allowed the multicellular organization of skeletal cell types to recapitulate complicated skeletal development and metabolism. Similarly, several genetic diseases of the skeleton have been modeled using patient-derived induced pluripotent stem cells and genome-editing technologies. Model-based drug screening is a powerful tool for identifying drug candidates. This review briefly summarizes our current understanding of the embryonic development of skeletal tissues and introduces the current state-of-the-art hPSC methods for recapitulating skeletal development, metabolism, and diseases. We also discuss the current limitations and future perspectives for applications of the hPSC-based modeling system in precision medicine in this research field.

Stem Cell Therapy for the Treatment of Amyotrophic Lateral Sclerosis: Comparison of the Efficacy of Mesenchymal Stem Cells, Neural Stem Cells, and Induced Pluripotent Stem Cells

BACKGROUND/OBJECTIVES

Amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, is a debilitating, incurable neurodegenerative disorder characterised by motor neuron death in the spinal cord, brainstem, and motor cortex. With an incidence rate of about 4.42 cases per 100,000 people annually, ALS severely impacts motor function and quality of life, causing progressive muscle atrophy, spasticity, paralysis, and eventually death. The cause of ALS is largely unknown, with 90% of cases being sporadic and 10% familial. Current research targets molecular mechanisms of inflammation, excitotoxicity, aggregation-prone proteins, and proteinopathy.

METHODS

This review evaluates the efficacy of three stem cell types in ALS treatment: mesenchymal stem cells (MSCs), neural stem cells (NSCs), and induced pluripotent stem cells (iPSCs).

RESULTS

MSCs, derived from various tissues, show neuroprotective and regenerative qualities, with clinical trials suggesting potential benefits but limited by small sample sizes and non-randomised designs. NSCs, isolated from the fetal spinal cord or brain, demonstrate promise in animal models but face functional integration and ethical challenges. iPSCs, created by reprogramming patient-specific somatic cells, offer a novel approach by potentially replacing or supporting neurons. iPSC therapy addresses ethical issues related to embryonic stem cells but encounters challenges regarding genotoxicity and epigenetic irregularities, somatic cell sources, privacy concerns, the need for extensive clinical trials, and high reprogramming costs.

CONCLUSIONS

This research is significant for advancing ALS treatment beyond symptomatic relief and modest survival extensions to actively modifying disease progression and improving patient outcomes. Successful stem cell therapies could lead to new ALS treatments, slowing motor function loss and reducing symptom severity.

Human stem cell-specific epigenetic signatures control transgene expression

Human stem cell-derived models have emerged as an important platform to study tissue differentiation and disease mechanisms. Those models could capitalize on biochemical and cell biological methodologies such as omics, autophagy, and organelle dynamics. However, epigenetic silencing in stem cells creates a barrier to apply genetically encoded tools. Here we investigate the molecular mechanisms underlying exogenously expressed gene silencing by employing multiple commonly used promoters in human induced pluripotent stem cells (iPSCs), glioblastoma cells (GBM), and embryonic kidney cells (HEK). We discover that all promoters tested are highly methylated on the CpG island regions with lower protein expression in iPSCs, as compared to non-iPSCs. Elongation factor 1 alpha short (EF1α short or EFS) promoter, which has fewer CpG island number compared to the other promoters, can drive relatively higher gene expression in iPSCs, despite CpG methylation. Adding a minimal A2 ubiquitous chromatin opening element (minimal A2 UCOE or miniUCOE) upstream of a promoter inhibits CpG methylation and enhances gene expression in iPSCs. Our results demonstrate stem cell type-specific epigenetic modification of transgenic promoter region and provide useful information for designing anti-silencing strategies to increase transgene expression in iPSCs.

The organoid modeling approach to understanding the mechanisms underlying neurodegeneration: A comprehensive review

Neurodegenerative diseases (NDs) are severe disorders of the nervous system, and their causes are still not completely understood. Modeling the complex pathological mechanisms underlying NDs has long posed a significant challenge, as traditional in vitro and animal models often fail to accurately recapitulate the disease phenotypes observed in humans; however, the rise of organoid technology has opened new approaches for developing innovative disease models that can better capture the nuances of the human nervous system. Organoid platforms hold promise for contributing to the design of future clinical trials and advancing our understanding of these devastating neurological conditions and accelerate the discovery of effective, personalized therapies. This comprehensive review discusses the recent advancements in neural organoid technology and explores the potential of patient-derived organoids for modeling NDs conditions and presents findings related to the mechanisms of their development or progress.

Extracellular Vesicles from Human Induced Pluripotent Stem Cells Exhibit a Unique MicroRNA and CircRNA Signature

Extracellular vesicles (EV) have emerged as promising cell-free therapeutics in regenerative medicine. However, translating primary cell line-derived EV to clinical applications requires large-scale manufacturing and several challenges, such as replicative senescence, donor heterogeneity, and genetic instability. To address these limitations, we used a reprogramming approach to generate human induced pluripotent stem cells (hiPSC) from the young source of cord blood mesenchymal stem/stromal cells (CBMSC). Capitalizing on their inexhaustible supply potential, hiPSC offer an attractive EV reservoir. Our approach encompassed an exhaustive characterization of hiPSC-EV, aligning with the rigorous MISEV2023 guidelines. Analyses demonstrated physical features compatible with small EV (sEV) and established their identity and purity. Moreover, the sEV-shuttled non-coding (nc) RNA landscape, focusing on the microRNA and circular RNA cargo, completed the molecular signature. The kinetics of the hiPSC-sEV release and cell internalization assays unveiled robust EV production and consistent uptake by human neurons. Furthermore, hiPSC-sEV demonstrated ex vivo cell tissue-protective properties. Finally, via bioinformatics, the potential involvement of the ncRNA cargo in the hiPSC-sEV biological effects was explored. This study significantly advances the understanding of pluripotent stem cell-derived EV. We propose cord blood MSC-derived hiPSC as a promising source for potentially therapeutic sEV.

Comparison of iPSC-derived human intestinal epithelial cells with Caco-2 cells and human in vivo data after exposure to Lactiplantibacillus plantarum WCFS1

To investigate intestinal health and its potential disruptors in vitro, representative models are required. Human induced pluripotent stem cell (hiPSC)-derived intestinal epithelial cells (IECs) more closely resemble the in vivo intestinal tissue than conventional in vitro models like human colonic adenocarcinoma Caco-2 cells. However, the potential of IECs to study immune-related responses upon external stimuli has not been investigated in detail yet. The aim of the current study was to evaluate immune-related effects of IECs by challenging them with a pro-inflammatory cytokine cocktail. Subsequently, the effects of Lactiplantibacillus plantarum WCFS1 were investigated in unchallenged and challenged IECs. All exposures were compared to Caco-2 cells and in vivo data where possible. Upon the inflammatory challenge, IECs and Caco-2 cells induced a pro-inflammatory response which was strongest in IECs. Heat-killed L. plantarum exerted the strongest effect on immune parameters in the IEC model, while L. plantarum in the stationary growth phase had most pronounced effects on immune-related gene expression in Caco-2 cells. Unfortunately, comparison to in vivo transcriptomics data showed limited similarities, which could be explained by essential differences in the study setups. Altogether, hiPSC-derived IECs show a high potential as a model to study immune-related responses in the intestinal epithelium in vitro.

Targeting epigenetic dysregulation in autism spectrum disorders

Autism spectrum disorders (ASD) comprise a range of neurodevelopmental pathologies characterized by deficits in social interaction and repetitive behaviors, collectively affecting almost 1% of the worldwide population. Deciphering the etiology of ASD has proven challenging due to the intricate interplay of genetic and environmental factors and the variety of molecular pathways affected. Epigenomic alterations have emerged as key players in ASD etiology. Their research has led to the identification of biomarkers for diagnosis and pinpointed specific gene targets for therapeutic interventions. This review examines the role of epigenetic alterations, resulting from both genetic and environmental influences, as a central causative factor in ASD, delving into its contribution to pathogenesis and treatment strategies.

In vitro modelling of the neurovascular unit for ischemic stroke research: Emphasis on human cell applications and 3D model design

Ischemic stroke has garnered global medical attention as one of the most serious cerebrovascular diseases. The mechanisms involved in both the development and recovery phases of ischemic stroke are complex, involving intricate interactions among different types of cells, each with its own unique functions. To better understand the possible pathogenesis, neurovascular unit (NVU), a concept comprising neurons, endothelial cells, mural cells, glial cells, and extracellular matrix components, has been used in analysing various brain diseases, particularly in ischemic stroke, aiming to depict the interactions between cerebral vasculature and neural cells. While in vivo models often face limitations in terms of reproducibility and the ability to precisely mimic human pathophysiology, it is now important to establish in vitro NVU models for ischemic stroke research. In order to accurately portray the pathological processes occurring within the brain, a diverse array of NVU 2D and 3D in vitro models, each possessing unique characteristics and advantages, have been meticulously developed. This review presents a comprehensive overview of recent advancements in in vitro models specifically tailored for investigating ischemic stroke. Through a systematic categorization of these developments, we elucidate the intricate links between NVU components and the pathogenesis of ischemic stroke. Furthermore, we explore the distinct advantages offered by innovative NVU models, notably 3D models, which closely emulate in vivo conditions. Additionally, an examination of current therapeutic modalities for ischemic stroke developed utilizing in vitro NVU models is provided. Serving as a valuable reference, this review aids in the design and implementation of effective in vitro models for ischemic stroke research.

The Roles of Micro- and Nanoscale Materials in Cell-Engineering Systems

Customizable manufacturing of ex vivo cell engineering is driven by the need for innovations in the biomedical field and holds substantial potential for addressing current therapeutic challenges; but it is still only in its infancy. Micro- and nanoscale-engineered materials are increasingly used to control core cell-level functions in cellular engineering. By reprogramming or redirecting targeted cells for extremely precise functions, these advanced materials offer new possibilities. This influences the modularity of cell reprogramming and reengineering, making these materials part of versatile and emerging technologies. Here, the roles of micro- and nanoscale materials in cell engineering are highlighted, demonstrating how they can be adaptively controlled to regulate cellular reprogramming and core cell-level functions, including differentiation, proliferation, adhesion, user-defined gene expression, and epigenetic changes. The current reprogramming routes used to achieve pluripotency from somatic cells and the significant potential of induced pluripotent stem cell technology for translational biomedical research are covered. Recent advances in nonviral intracellular delivery modalities for cell reprogramming and their constraints are evaluated. This paper focuses on emerging physical and combinatorial approaches of intracellular delivery for cell engineering, revealing the capabilities and limitations of these routes. It is showcased how these programmable materials are continually being explored as customizable tools for inducing biophysical stimulation. Harnessing the power of micro- and nanoscale-engineered materials will be a step change in the design of cell engineering, producing a suite of powerful tools for addressing potential future challenges in therapeutic cell engineering.

Reporter Alleles in hiPSCs: Visual Cues on Development and Disease

Reporter alleles are essential for advancing research with human induced pluripotent stem cells (hiPSCs), notably in developmental biology and disease modeling. This study investigates the state-of-the-art gene-editing techniques tailored for generating reporter alleles in hiPSCs, emphasizing their effectiveness in investigating cellular dynamics and disease mechanisms. Various methodologies, including the application of CRISPR/Cas9 technology, are discussed for accurately integrating reporter genes into the specific genomic loci. The synthesis of findings from the studies utilizing these reporter alleles reveals insights into developmental processes, genetic disorder modeling, and therapeutic screening, consolidating the existing knowledge. These hiPSC-derived models demonstrate remarkable versatility in replicating human diseases and evaluating drug efficacy, thereby accelerating translational research. Furthermore, this review addresses challenges and future directions in refining the reporter allele design and application to bolster their reliability and relevance in biomedical research. Overall, this investigation offers a comprehensive perspective on the methodologies, applications, and implications of reporter alleles in hiPSC-based studies, underscoring their essential role in advancing both fundamental scientific understanding and clinical practice.

Modeling Lewy body disease with SNCA triplication iPSC-derived cortical organoids and identifying therapeutic drugs

Aggregated α-synuclein (α-SYN) proteins, encoded by the SNCA gene, are hallmarks of Lewy body disease (LBD), affecting multiple brain regions. However, the specific mechanisms underlying α-SYN pathology in cortical neurons, crucial for LBD-associated dementia, remain unclear. Here, we recapitulated α-SYN pathologies in human induced pluripotent stem cells (iPSCs)-derived cortical organoids generated from patients with LBD with SNCA gene triplication. Single-cell RNA sequencing, combined with functional and molecular validation, identified synaptic and mitochondrial dysfunction in excitatory neurons exhibiting high expression of the SNCA gene, aligning with observations in the cortex of autopsy-confirmed LBD human brains. Furthermore, we screened 1280 Food and Drug Administration-approved drugs and identified four candidates (entacapone, tolcapone, phenazopyridine hydrochloride, and zalcitabine) that inhibited α-SYN seeding activity in real-time quaking-induced conversion assays with human brains, reduced α-SYN aggregation, and alleviated mitochondrial dysfunction in SNCA triplication organoids and excitatory neurons. Our findings establish human cortical LBD models and suggest potential therapeutic drugs targeting α-SYN aggregation for LBD.

Advancing Parkinson's disease treatment: cell replacement therapy with neurons derived from pluripotent stem cells

The motor symptoms of Parkinson's disease (PD) are caused by the progressive loss of dopamine neurons from the substantia nigra. There are currently no treatments that can slow or reverse the neurodegeneration. To restore the lost neurons, international groups have initiated clinical trials using human embryonic or induced pluripotent stem cells (PSCs) to derive dopamine neuron precursors that are used as transplants to replace the lost neurons. Proof-of-principle experiments in the 1980s and 1990s showed that grafts of fetal ventral mesencephalon, which contains the precursors of the substantial nigra, could, under rare circumstances, reverse symptoms of the disease. Improvements in PSC technology and genomics have inspired researchers to design clinical trials using PSC-derived dopamine neuron precursors as cell replacement therapy for PD. We focus here on 4 such first-in-human clinical trials that have begun in the US, Europe, and Japan. We provide an overview of the sources of PSCs and the methods used to generate cells for transplantation. We discuss pros and cons of strategies for allogeneic, immune-matched, and autologous approaches and novel methods for overcoming rejection by the immune system. We consider challenges for safety and efficacy of the cells for durable engraftment, focusing on the genomics-based quality control methods to assure that the cells will not become cancerous. Finally, since clinical trials like these have never been undertaken before, we comment on the value of cooperation among rivals to contribute to advancements that will finally provide relief for the millions suffering from the symptoms of PD.

Validating human induced pluripotent stem cell-specific quality control tests for the release of an intermediate drug product in a Good Manufacturing Practice quality system

One of the challenges in Good Manufacturing Practice (GMP)-compliant human induced pluripotent stem cell (hiPSC) production is the validation of quality control (QC) tests specific for hiPSCs, which are required for GMP batch release. This study presents a comprehensive description of the validation process for hiPSC-specific GMP-compliant QC assays; more specifically, the validation of assays to assess the potential presence of residual episomal vectors (REVs), the expression of markers of the undifferentiated state and the directed differentiation potential of hiPSCs. Critical aspects and specific acceptance criteria were formulated in a validation plan prior to assay validation. Assay specificity, sensitivity and reproducibility were tested, and the equipment used for each assay was subjected to performance qualification. A minimum input of 20 000 cells (120 ng of genomic DNA) was defined for accurate determination of the presence of REVs. Furthermore, since vector loss in hiPSC lines is a passage-dependent process, we advocate screening for REVs between passages eight and 10, as testing at earlier passages might lead to unnecessary rejection of hiPSC lines. The cutoff value for assessment of markers of the undifferentiated state was set to the expression of at least three individual markers on at least 75% of the cells. When multi-color flow cytometry panels are used, a fluorescence minus one control is advised to ensure the control for fluorescent spread. For the assay to assess the directed differentiation potential, the detection limit was set to two of three positive lineage-specific markers for each of the three individual germ layers. All of our assays proved to be reproducible and specific. Our data demonstrate that our implemented analytical procedures are suitable as QC assays for the batch release of GMP-compliant hiPSCs.

Chemotherapy-induced peripheral neuropathy models constructed from human induced pluripotent stem cells and directly converted cells: a systematic review

ABSTRACT

Developments in human cellular reprogramming now allow for the generation of human neurons for in vitro disease modelling. This technique has since been used for chemotherapy-induced peripheral neuropathy (CIPN) research, resulting in the description of numerous CIPN models constructed from human neurons. This systematic review provides a critical analysis of available models and their methodological considerations (ie, used cell type and source, CIPN induction strategy, and validation method) for prospective researchers aiming to incorporate human in vitro models of CIPN in their research. The search strategy was developed with assistance from a clinical librarian and conducted in MEDLINE (PubMed) and Embase (Ovid) on September 26, 2023. Twenty-six peer-reviewed experimental studies presenting original data about human reprogrammed nonmotor neuron cell culture systems and relevant market available chemotherapeutics drugs were included. Virtually, all recent reports modeled CIPN using nociceptive dorsal root ganglion neurons. Drugs known to cause the highest incidence of CIPN were most used. Furthermore, treatment effects were almost exclusively validated by the acute effects of chemotherapeutics on neurite dynamics and cytotoxicity parameters, enabling the extrapolation of the half-maximal inhibitory concentration for the 4 most used chemotherapeutics. Overall, substantial heterogeneity was observed in the way studies applied chemotherapy and reported their findings. We therefore propose 6 suggestions to improve the clinical relevance and appropriateness of human cellular reprogramming-derived CIPN models.

Unlocking the potential of iPSC-derived immune cells: engineering iNK and iT cells for cutting-edge immunotherapy

Induced pluripotent stem cells (iPSCs) have emerged as a revolutionary tool in cell therapies due to their ability to differentiate into various cell types, unlimited supply, and potential as off-the-shelf cell products. New advances in iPSC-derived immune cells have generated potent iNK and iT cells which showed robust killing of cancer cells in animal models and clinical trials. With the advent of advanced genome editing technologies that enable the development of highly engineered cells, here we outline 12 strategies to engineer iPSCs to overcome limitations and challenges of current cell-based immunotherapies, including safety switches, stealth edits, avoiding graft-versus-host disease (GvHD), targeting, reduced lymphodepletion, efficient differentiation, increased in vivo persistence, stemness, metabolic fitness, homing/trafficking, and overcoming suppressive tumor microenvironment and stromal cell barrier. With the development of advanced genome editing techniques, it is now possible to insert large DNA sequences into precise genomic locations without the need for DNA double strand breaks, enabling the potential for multiplexed knock out and insertion. These technological breakthroughs have made it possible to engineer complex cell therapy products at unprecedented speed and efficiency. The combination of iPSC derived iNK, iT and advanced gene editing techniques provides new opportunities and could lead to a new era for next generation of cell immunotherapies.

Forward programming of hiPSCs towards beta-like cells using Ngn3, Pdx1, and MafA

Transplantation of stem cell-derived β-cells is a promising therapeutic advancement in the treatment of type 1 diabetes mellitus. A current limitation of this approach is the long differentiation timeline that generates a heterogeneous population of pancreatic endocrine cells. To address this limitation, an inducible lentiviral overexpression system of mature β-cell markers was introduced into human induced-pluripotent stem cells (hiPSCs). Following the selection of the successfully transduced hiPSCs, the cells were treated with doxycycline in the pancreatic progenitor induction medium to support their transition toward the pancreatic lineage. Cells cultured with doxycycline presented the markers of interest, NGN3, PDX1, and MAFA, after five days of culture, and glucose-stimulated insulin secretion assays demonstrated that the cells were glucose-responsive in a monolayer culture. When cultured as a spheroid, the markers of interest and insulin secretion in a static glucose-stimulated insulin secretion assay were maintained; however, insulin secretion upon consecutive glucose challenges was limited. Comparison to human fetal and adult donor tissues identified that although the hiPSC-derived spheroids present similar markers to adult insulin-producing cells, they are functionally representative of fetal development. Together, these results suggest that with optimization of the temporal expression of these markers, forward programming of hiPSCs towards insulin-producing cells could be a possible alternative for islet transplantation.

Exploiting urine-derived induced pluripotent stem cells for advancing precision medicine in cell therapy, disease modeling, and drug testing

The field of regenerative medicine has witnessed remarkable advancements with the emergence of induced pluripotent stem cells (iPSCs) derived from a variety of sources. Among these, urine-derived induced pluripotent stem cells (u-iPSCs) have garnered substantial attention due to their non-invasive and patient-friendly acquisition method. This review manuscript delves into the potential and application of u-iPSCs in advancing precision medicine, particularly in the realms of drug testing, disease modeling, and cell therapy. U-iPSCs are generated through the reprogramming of somatic cells found in urine samples, offering a unique and renewable source of patient-specific pluripotent cells. Their utility in drug testing has revolutionized the pharmaceutical industry by providing personalized platforms for drug screening, toxicity assessment, and efficacy evaluation. The availability of u-iPSCs with diverse genetic backgrounds facilitates the development of tailored therapeutic approaches, minimizing adverse effects and optimizing treatment outcomes. Furthermore, u-iPSCs have demonstrated remarkable efficacy in disease modeling, allowing researchers to recapitulate patient-specific pathologies in vitro. This not only enhances our understanding of disease mechanisms but also serves as a valuable tool for drug discovery and development. In addition, u-iPSC-based disease models offer a platform for studying rare and genetically complex diseases, often underserved by traditional research methods. The versatility of u-iPSCs extends to cell therapy applications, where they hold immense promise for regenerative medicine. Their potential to differentiate into various cell types, including neurons, cardiomyocytes, and hepatocytes, enables the development of patient-specific cell replacement therapies. This personalized approach can revolutionize the treatment of degenerative diseases, organ failure, and tissue damage by minimizing immune rejection and optimizing therapeutic outcomes. However, several challenges and considerations, such as standardization of reprogramming protocols, genomic stability, and scalability, must be addressed to fully exploit u-iPSCs' potential in precision medicine. In conclusion, this review underscores the transformative impact of u-iPSCs on advancing precision medicine and highlights the future prospects and challenges in harnessing this innovative technology for improved healthcare outcomes.

OGT and OGA gene-edited human induced pluripotent stem cells for dissecting the functional roles of O-GlcNAcylation in hematopoiesis

Hematopoiesis continues throughout life to produce all types of blood cells from hematopoietic stem cells (HSCs). Metabolic state is a known regulator of HSC self-renewal and differentiation, but whether and how metabolic sensor O-GlcNAcylation, which can be modulated via an inhibition of its cycling enzymes O-GlcNAcase (OGA) and O-GlcNAc transferase (OGT), contributes to hematopoiesis remains largely unknown. Herein, isogenic, single-cell clones of OGA-depleted (OGAi) and OGT-depleted (OGTi) human induced pluripotent stem cells (hiPSCs) were successfully generated from the master hiPSC line MUSIi012-A, which were reprogrammed from CD34+ hematopoietic stem/progenitor cells (HSPCs) containing epigenetic memory. The established OGAi and OGTi hiPSCs exhibiting an increase or decrease in cellular O-GlcNAcylation concomitant with their loss of OGA and OGT, respectively, appeared normal in phenotype and karyotype, and retained pluripotency, although they may favor differentiation toward certain germ lineages. Upon hematopoietic differentiation through mesoderm induction and endothelial-to-hematopoietic transition, we found that OGA inhibition accelerates hiPSC commitment toward HSPCs and that disruption of O-GlcNAc homeostasis affects their commitment toward erythroid lineage. The differentiated HSPCs from all groups were capable of giving rise to all hematopoietic progenitors, thus confirming their functional characteristics. Altogether, the established single-cell clones of OGTi and OGAi hiPSCs represent a valuable platform for further dissecting the roles of O-GlcNAcylation in blood cell development at various stages and lineages of blood cells. The incomplete knockout of OGA and OGT in these hiPSCs makes them susceptible to additional manipulation, i.e., by small molecules, allowing the molecular dynamics studies of O-GlcNAcylation.

Dysregulation of Immune Tolerance to Autologous iPSCs and Their Differentiated Derivatives

Induced pluripotent stem cells (iPSCs), capable of differentiating into any cell type, are a promising tool for solving the problem of donor organ shortage. In addition, reprogramming technology makes it possible to obtain a personalized, i.e., patient-specific, cell product transplantation of which should not cause problems related to histocompatibility of the transplanted tissues and organs. At the same time, inconsistent information about the main advantage of autologous iPSC-derivatives - lack of immunogenicity - still casts doubt on the possibility of using such cells beyond immunosuppressive therapy protocols. This review is devoted to immunogenic properties of the syngeneic and autologous iPSCs and their derivatives, as well as to the reasons for dysregulation of their immune tolerance.

Recent Findings on Therapeutic Cancer Vaccines: An Updated Review

Cancer remains one of the global leading causes of death and various vaccines have been developed over the years against it, including cell-based, nucleic acid-based, and viral-based cancer vaccines. Although many vaccines have been effective in in vivo and clinical studies and some have been FDA-approved, there are major limitations to overcome: (1) developing one universal vaccine for a specific cancer is difficult, as tumors with different antigens are different for different individuals, (2) the tumor antigens may be similar to the body's own antigens, and (3) there is the possibility of cancer recurrence. Therefore, developing personalized cancer vaccines with the ability to distinguish between the tumor and the body's antigens is indispensable. This paper provides a comprehensive review of different types of cancer vaccines and highlights important factors necessary for developing efficient cancer vaccines. Moreover, the application of other technologies in cancer therapy is discussed. Finally, several insights and conclusions are presented, such as the possibility of using cold plasma and cancer stem cells in developing future cancer vaccines, to tackle the major limitations in the cancer vaccine developmental process.

Retinal Ciliopathies and Potential Gene Therapies: A Focus on Human iPSC-Derived Organoid Models

The human photoreceptor function is dependent on a highly specialised cilium. Perturbation of cilial function can often lead to death of the photoreceptor and loss of vision. Retinal ciliopathies are a genetically diverse range of inherited retinal disorders affecting aspects of the photoreceptor cilium. Despite advances in the understanding of retinal ciliopathies utilising animal disease models, they can often lack the ability to accurately mimic the observed patient phenotype, possibly due to structural and functional deviations from the human retina. Human-induced pluripotent stem cells (hiPSCs) can be utilised to generate an alternative disease model, the 3D retinal organoid, which contains all major retinal cell types including photoreceptors complete with cilial structures. These retinal organoids facilitate the study of disease mechanisms and potential therapies in a human-derived system. Three-dimensional retinal organoids are still a developing technology, and despite impressive progress, several limitations remain. This review will discuss the state of hiPSC-derived retinal organoid technology for accurately modelling prominent retinal ciliopathies related to genes, including RPGR, CEP290, MYO7A, and USH2A. Additionally, we will discuss the development of novel gene therapy approaches targeting retinal ciliopathies, including the delivery of large genes and gene-editing techniques.

Stem cell modeling of nervous system tumors

Nervous system tumors, particularly brain tumors, represent the most common tumors in children and one of the most lethal tumors in adults. Despite decades of research, there are few effective therapies for these cancers. Although human nervous system tumor cells and genetically engineered mouse models have served as excellent platforms for drug discovery and preclinical testing, they have limitations with respect to accurately recapitulating important aspects of the pathobiology of spontaneously arising human tumors. For this reason, attention has turned to the deployment of human stem cell engineering involving human embryonic or induced pluripotent stem cells, in which genetic alterations associated with nervous system cancers can be introduced. These stem cells can be used to create self-assembling three-dimensional cerebral organoids that preserve key features of the developing human brain. Moreover, stem cell-engineered lines are amenable to xenotransplantation into mice as a platform to investigate the tumor cell of origin, discover cancer evolutionary trajectories and identify therapeutic vulnerabilities. In this article, we review the current state of human stem cell models of nervous system tumors, discuss their advantages and disadvantages, and provide consensus recommendations for future research.

iPSCs as a groundbreaking tool for the study of adverse drug reactions: A new avenue for personalized therapy

Induced pluripotent stem cells (iPSCs), obtained by reprogramming different somatic cell types, represent a promising tool for the study of drug toxicities, especially in the context of personalized medicine. Indeed, these cells retain the same genetic heritage of the donor, allowing the development of personalized models. In addition, they represent a useful tool for the study of adverse drug reactions (ADRs) in special populations, such as pediatric patients, which are often poorly represented in clinical trials due to ethical issues. Particularly, iPSCs can be differentiated into any tissue of the human body, following several protocols which use different stimuli to induce specific differentiation processes. Differentiated cells also maintain the genetic heritage of the donor, and therefore are suitable for personalized pharmacological studies; moreover, iPSC-derived differentiated cells are a valuable tool for the investigation of the mechanisms underlying the physiological differentiation processes. iPSCs-derived organoids represent another important tool for the study of ADRs. Precisely, organoids are in vitro 3D models which better represent the native organ, both from a structural and a functional point of view. Moreover, in the same way as iPSC-derived 2D models, iPSC-derived organoids are appropriate personalized models since they retain the genetic heritage of the donor. In comparison to other in vitro models, iPSC-derived organoids present advantages in terms of versatility, patient-specificity, and ethical issues. This review aims to provide an updated report of the employment of iPSCs, and 2D and 3D models derived from these, for the study of ADRs. This article is categorized under: Cancer > Stem Cells and Development.

CTCF deletion alters the pluripotency and DNA methylation profile of human iPSCs

Pluripotent stem cells are characterized by their differentiation potential toward endoderm, mesoderm, and ectoderm. However, it is still largely unclear how these cell-fate decisions are mediated by epigenetic mechanisms. In this study, we explored the relevance of CCCTC-binding factor (CTCF), a zinc finger-containing DNA-binding protein, which mediates long-range chromatin organization, for directed cell-fate determination. We generated human induced pluripotent stem cell (iPSC) lines with deletions in the protein-coding region in exon 3 of CTCF, resulting in shorter transcripts and overall reduced protein expression. Chromatin immunoprecipitation showed a considerable loss of CTCF binding to target sites. The CTCF deletions resulted in slower growth and modest global changes in gene expression, with downregulation of a subset of pluripotency-associated genes and neuroectodermal genes. CTCF deletion also evoked DNA methylation changes, which were moderately associated with differential gene expression. Notably, CTCF-deletions lead to upregulation of endo-mesodermal associated marker genes and epigenetic signatures, whereas ectodermal differentiation was defective. These results indicate that CTCF plays an important role in the maintenance of pluripotency and differentiation, especially towards ectodermal lineages.

Exploring the promising potential of induced pluripotent stem cells in cancer research and therapy

The advent of iPSCs has brought about a significant transformation in stem cell research, opening up promising avenues for advancing cancer treatment. The formation of cancer is a multifaceted process influenced by genetic, epigenetic, and environmental factors. iPSCs offer a distinctive platform for investigating the origin of cancer, paving the way for novel approaches to cancer treatment, drug testing, and tailored medical interventions. This review article will provide an overview of the science behind iPSCs, the current limitations and challenges in iPSC-based cancer therapy, the ethical and social implications, and the comparative analysis with other stem cell types for cancer treatment. The article will also discuss the applications of iPSCs in tumorigenesis, the future of iPSCs in tumorigenesis research, and highlight successful case studies utilizing iPSCs in tumorigenesis research. The conclusion will summarize the advancements made in iPSC-based tumorigenesis research and the importance of continued investment in iPSC research to unlock the full potential of these cells.

Mucopolysaccharidosis IVA: Current Disease Models and Drawbacks

Mucopolysaccharidosis IVA (MPS IVA) is a rare disorder caused by mutations in the N-acetylgalactosamine-6-sulfate-sulfatase (GALNS) encoding gene. GALNS leads to the lysosomal degradation of the glycosaminoglyccreasans keratan sulfate and chondroitin 6-sulfate. Impaired GALNS enzymes result in skeletal and non-skeletal complications in patients. For years, the MPS IVA pathogenesis and the assessment of promising drugs have been evaluated using in vitro (primarily fibroblasts) and in vivo (mainly mouse) models. Even though value information has been raised from those studies, these models have several limitations. For instance, chondrocytes have been well recognized as primary cells affected in MPS IVA and responsible for displaying bone development impairment in MPS IVA patients; nonetheless, only a few investigations have used those cells to evaluate basic and applied concepts. Likewise, current animal models are extensively represented by mice lacking GALNS expression; however, it is well known that MPS IVA mice do not recapitulate the skeletal dysplasia observed in humans, making some comparisons difficult. This manuscript reviews the current in vitro and in vivo MPS IVA models and their drawbacks.

Vascular organoids: unveiling advantages, applications, challenges, and disease modelling strategies

Understanding mechanisms and manifestations of cardiovascular risk factors, including diabetes, on vascular cells such as endothelial cells, pericytes, and vascular smooth muscle cells, remains elusive partly due to the lack of appropriate disease models. Therefore, here we explore different aspects for the development of advanced 3D in vitro disease models that recapitulate human blood vessel complications using patient-derived induced pluripotent stem cells, which retain the epigenetic, transcriptomic, and metabolic memory of their patient-of-origin. In this review, we highlight the superiority of 3D blood vessel organoids over conventional 2D cell culture systems for vascular research. We outline the key benefits of vascular organoids in both health and disease contexts and discuss the current challenges associated with organoid technology, providing potential solutions. Furthermore, we discuss the diverse applications of vascular organoids and emphasize the importance of incorporating all relevant cellular components in a 3D model to accurately recapitulate vascular pathophysiology. As a specific example, we present a comprehensive overview of diabetic vasculopathy, demonstrating how the interplay of different vascular cell types is critical for the successful modelling of complex disease processes in vitro. Finally, we propose a strategy for creating an organ-specific diabetic vasculopathy model, serving as a valuable template for modelling other types of vascular complications in cardiovascular diseases by incorporating disease-specific stressors and organotypic modifications.

Patient-specific primary and pluripotent stem cell-derived stromal cells recapitulate key aspects of arrhythmogenic cardiomyopathy

Primary cardiac mesenchymal stromal cells (C-MSCs) can promote the aberrant remodeling of cardiac tissue that characterizes arrhythmogenic cardiomyopathy (ACM) by differentiating into adipocytes and myofibroblasts. These cells' limitations, including restricted access to primary material and its manipulation have been overcome by the advancement of human induced pluripotent stem cells (hiPSCs), and their ability to differentiate towards the cardiac stromal population. C-MSCs derived from hiPSCs make it possible to work with virtually unlimited numbers of cells that are genetically identical to the cells of origin. We performed in vitro experiments on primary stromal cells (Primary) and hiPSC-derived stromal cells (hiPSC-D) to compare them as tools to model ACM. Both Primary and hiPSC-D cells expressed mesenchymal surface markers and possessed typical MSC differentiation potentials. hiPSC-D expressed desmosomal genes and proteins and shared a similar transcriptomic profile with Primary cells. Furthermore, ACM hiPSC-D exhibited higher propensity to accumulate lipid droplets and collagen compared to healthy control cells, similar to their primary counterparts. Therefore, both Primary and hiPSC-D cardiac stromal cells obtained from ACM patients can be used to model aspects of the disease. The choice of the most suitable model will depend on experimental needs and on the availability of human source samples.

Potential and Limitations of Induced Pluripotent Stem Cells-Derived Mesenchymal Stem Cells in Musculoskeletal Disorders Treatment

The burden of musculoskeletal disorders (MSK) is increasing worldwide. It affects millions of people worldwide, decreases their quality of life, and can cause mortality. The treatment of such conditions is challenging and often requires surgery. Thus, it is necessary to discuss new strategies. The therapeutic potential of mesenchymal stem cells (MSC) in several diseases has been investigated with relative success. However, this potential is hindered by their limited stemness and expansion ability in vitro and their high donor variability. MSC derived from induced pluripotent stem cells (iPSC) have emerged as an alternative treatment for MSK diseases. These cells present distinct features, such as a juvenile phenotype, in addition to higher stemness, proliferation, and differentiation potential than those of MSC. Here, we review the opportunities, challenges, and applications of iPSC as relevant clinical therapeutic cell sources for MSK disorders. We discuss iPSC sources from which to derive iMSC and the advantages and disadvantages of iMSC over MSC as a therapeutic approach. We further summarize the main preclinical and clinical studies exploring the therapeutic potential of iMSC in MSK disorders.

Revealing the developmental origin and lineage predilection of neural progenitors within human bone marrow via single-cell analysis: implications for regenerative medicine

BACKGROUND

Human bone marrow stromal cells (BMSCs) are an easily accessible and expandable progenitor population with the capacity to generate neural cell types in addition to mesoderm. Lineage tracing studies in transgenic animals have indicated Nestin + BMSCs to be descended from the truncal neural crest. Single-cell analysis provides a means to identify the developmental origin and identity of human BMSC-derived neural progenitors when lineage tracing remains infeasible. This is a prerequisite towards translational application.

METHODS

We attained transcriptomic profiles of embryonic long bone, adult human bone marrow, cultured BMSCs and BMSC-derived neurospheres. Integrated scRNAseq analysis was supplemented by characterization of cells during culture expansion and following provision of growth factors and signalling agonists to bias lineage.

RESULTS

Reconstructed pseudotime upon the integrated dataset indicated distinct neural and osteogenic differentiation trajectories. The starting state towards the neural differentiation trajectory consisted of Nestin + /MKI67 + BMSCs, which could also be diverted towards the osteogenic trajectory via a branch point. Nestin + /PDGFRA + BMSCs responded to neurosphere culture conditions to generate a subpopulation of cells with a neuronal phenotype according to marker expression and gene ontogeny analysis that occupied the end state along the neural differentiation trajectory. Reconstructed pseudotime also revealed an upregulation of BMP4 expression during culture of BMSC-neurospheres. This provided the rationale for culture supplementation with the BMP signalling agonist SB4, which directed progenitors to upregulate Pax6 and downregulate Nestin.

CONCLUSIONS

This study suggested BMSCs originating from truncal neural crest to be the source of cells within long bone marrow possessing neural differentiation potential. Unravelling the transcriptomic dynamics of BMSC-derived neural progenitors promises to enhance differentiation efficiency and safety towards clinical application in cell therapy and disease modelling.

Physicochemical cues are not potent regulators of human dermal fibroblast trans-differentiation

Due to their inherent plasticity, dermal fibroblasts hold great promise in regenerative medicine. Although biological signals have been well-established as potent regulators of dermal fibroblast function, it is still unclear whether physiochemical cues can induce dermal fibroblast trans-differentiation. Herein, we evaluated the combined effect of surface topography, substrate rigidity, collagen type I coating and macromolecular crowding in human dermal fibroblast cultures. Our data indicate that tissue culture plastic and collagen type I coating increased cell proliferation and metabolic activity. None of the assessed in vitro microenvironment modulators affected cell viability. Anisotropic surface topography induced bidirectional cell morphology, especially on more rigid (1,000 kPa and 130 kPa) substrates. Macromolecular crowding increased various collagen types, but not fibronectin, deposition. Macromolecular crowding induced globular extracellular matrix deposition, independently of the properties of the substrate. At day 14 (longest time point assessed), macromolecular crowding downregulated tenascin C (in 9 out of the 14 groups), aggrecan (in 13 out of the 14 groups), osteonectin (in 13 out of the 14 groups), and collagen type I (in all groups). Overall, our data suggest that physicochemical cues (such surface topography, substrate rigidity, collagen coating and macromolecular crowding) are not as potent as biological signals in inducing dermal fibroblast trans-differentiation.

Replication stress causes delayed mitotic entry and chromosome 12 fragility at the ANKS1B large neuronal gene in human induced pluripotent stem cells

Substantial background level of replication stress is a feature of embryonic and induced pluripotent stem cells (iPSCs), which can predispose to numerical and structural chromosomal instability, including recurrent aberrations of chromosome 12. In differentiated cells, replication stress-sensitive genomic regions, including common fragile sites, are widely mapped through mitotic chromosome break induction by mild aphidicolin treatment, an inhibitor of replicative polymerases. IPSCs exhibit lower apoptotic threshold and higher repair capacity hindering fragile site mapping. Caffeine potentiates genotoxic effects and abrogates G2/M checkpoint delay induced by chemical and physical mutagens. Using 5-ethynyl-2'-deoxyuridine (EdU) for replication labeling, we characterized the mitotic entry dynamics of asynchronous iPSCs exposed to aphidicolin and/or caffeine. Under the adjusted timing of replication stress exposure accounting revealed cell cycle delay, higher metaphase chromosome breakage rate was observed in iPSCs compared to primary lymphocytes. Using differential chromosome staining and subsequent locus-specific fluorescent in situ hybridization, we mapped the FRA12L fragile site spanning the large neuronal ANKS1B gene at 12q23.1, which may contribute to recurrent chromosome 12 missegregation and rearrangements in iPSCs. Publicly available data on the ANKS1B genetic alterations and their possible functional impact are reviewed. Our study provides the first evidence of common fragile site induction in iPSCs and reveals potential somatic instability of a clinically relevant gene during early human development and in vitro cell expansion.

Transplantation of human induced pluripotent stem cell derived keratinocytes accelerates deep second-degree burn wound healing

BACKGROUND

Current evidence shows that human induced pluripotent stem cells (hiPSCs) can effectively differentiate into keratinocytes (KCs), but its effect on skin burn healing has not been reported.

AIM

To observe the effects of hiPSCs-derived KCs transplantation on skin burn healing in mice and to preliminarily reveal the underlying mechanisms.

METHODS

An analysis of differentially expressed genes in burn wounds based on GEO datasets GSE140926, and GSE27186 was established. A differentiation medium containing retinoic acid and bone morphogenetic protein 4 was applied to induce hiPSCs to differentiate into KCs. The expression of KCs marker proteins was detected using immunofluorescence staining. A model of a C57BL/6 mouse with deep cutaneous second-degree burn was created, and then phosphate buffered saline (PBS), hiPSCs-KCs, or hiPSCs-KCs with knockdown of COL7A1 were injected around the wound surface. The wound healing, re-epithelialization, engraftment of hiPSCs-KCs into wounds, proinflammatory factor level, and the NF-κB pathway proteins were assessed by hematoxylin-eosin staining, carboxifluorescein diacetate succinimidyl ester (CFSE) fluorescence staining, enzyme linked immunosorbent assay, and Western blotting on days 3, 7, and 14 after the injection, respectively. Moreover, the effects of COL7A1 knockdown on the proliferation and migration of hiPSCs-KCs were confirmed by immunohistochemistry, EdU, Transwell, and damage repair assays.

RESULTS

HiPSCs-KCs could express the hallmark proteins of KCs. COL7A1 was down-regulated in burn wound tissues and highly expressed in hiPSCs-KCs. Transplantation of hiPSCs-KCs into mice with burn wounds resulted in a significant decrease in wound area, an increase in wound re-epithelialization, a decrease in proinflammatory factors content, and an inhibition of NF-κB pathway activation compared to the PBS group. The in vitro assay showed that COL7A1 knockdown could rescue the inhibition of hiPSCs-KCs proliferation and migration, providing further evidence that COL7A1 speeds up burn wound healing by limiting cell proliferation and migration.

CONCLUSION

In deep, second-degree burn wounds, COL7A1 can promote KC proliferation and migration while also suppressing the inflammatory response.

How can clinical safety and efficacy concerns in stem cell therapy for spinal cord injury be overcome?

INTRODUCTION

Spinal cord injury (SCI) can lead to severe neurological dysfunction. Despite scientific and medical advances, clinically effective regenerative therapies including stem cells are lacking for SCI.

AREAS COVERED

This paper discusses translational challenges related to the safe, effective use of stem cells for SCI, with a focus on mesenchymal stem cells (MSCs), neural stem cells (NSCs), Schwann cells (SCs), olfactory ensheathing cells (OECs), oligodendrocyte precursor cells (OPCs), embryonic stem cells (ESCs), and induced pluripotent stem cells (iPSCs). We discuss approaches to enhance the efficacy of cell-based strategies by i) addressing patient heterogeneity and enhancing patient selection; ii) selecting cell type, cell source, cell developmental stage, and delivery technique; iii) enhancing graft integration and mitigating immune-mediated graft rejection; and iv) ensuring availability of cells. Additionally, we review strategies to optimize outcomes including combinatorial use of rehabilitation and discuss ways to mitigate potential risks of tumor formation associated with stem cell-based strategies.

EXPERT OPINION

Basic science research will drive translational advances to develop stem cell-based therapies for SCI. Genetic, serological, and imaging biomarkers may enable individualization of cell-based treatments. Moreover, combinatorial strategies will be required to enhance graft survival, migration and functional integration, to enable precision-based intervention.

The Importance of Stem Cells Isolated from Human Dental Pulp and Exfoliated Deciduous Teeth as Therapeutic Approach in Nervous System Pathologies

Despite decades of research, no therapies are available to halt or slow down the course of neuro-degenerative disorders. Most of the drugs developed to fight neurodegeneration are aimed to alleviate symptoms, but none has proven adequate in altering the course of the pathologies. Cell therapy has emerged as an intriguing alternative to the classical pharmacological approach. Cell therapy consists of the transplantation of stem cells that can be obtained from various embryonal and adult tissues. Whereas the former holds notable ethical issue, adult somatic stem cells can be obtained without major concerns. However, most adult stem cells, such as those derived from the bone marrow, are committed toward the mesodermal lineage, and hence need to be reprogrammed to induce the differentiation into the neurons. The discovery of neural crest stem cells in the dental pulp, both in adults' molar and in baby teeth (dental pulp stem cells and stem cells from human exfoliated deciduous teeth, respectively) prompted researchers to investigate their utility as therapy in nervous system disorders. In this review, we recapitulate the advancements on the application of these stem cells in preclinical models of neurodegenerative diseases, highlighting differences and analogies in their maintenance, differentiation, and potential clinical application.

Induced pluripotent and CD34+ stem cell derived myeloid cells display differential responses to particle and dust mite exposure

Myeloid cells form an essential component of initial responses to environmental hazards and toxic exposures. The ability to model these responses in vitro is central to efforts tasked with identifying hazardous materials and understanding mechanisms of injury and disease. Induced pluripotent stem cell (iPSC) derived cells have been suggested as alternatives to more established primary cell testing systems for these purposes. iPSC derived macrophage and dendritic like cells were compared to CD34+ haematopoietic stem cell derived populations using transcriptomic analysis. Using single cell sequencing-based characterisation of iPSC derived myeloid cells, we identified transitional, mature and M2 like macrophages as well as dendritic like antigen presenting cells and fibrocytes. Direct transcriptomic comparisons between iPSC and CD34+ cell derived populations revealed higher expression of myeloid differentiation genes such as MNDA, CSF1R and CSF2RB in CD34+ cells, while iPSC populations had higher fibroblastic and proliferative markers. Exposure of differentiated macrophage populations to nanoparticle alone or in combination with dust mite, resulted in differential gene expression on combination only, with responses markedly absent in iPSC compared to CD34+ derived cells. The lack of responsiveness in iPSC derived cells may be attributable to lower levels of dust mite component receptors CD14, TLR4, CLEC7A and CD36. In summary, iPSC derived myeloid cells display typical characteristics of immune cells but may lack a fully mature phenotype to adequately respond to environmental exposures.