Efficient induction of transgene-free human pluripotent stem cells using a vector based on Sendai virus, an RNA virus that does not integrate into the host genome

Current biological, chemical and physical gene delivery approaches for producing induced pluripotent stem cells (iPSCs)

The discovery of induced pluripotent stem cells (iPSCs) has revolutionized the research platform for disease modeling, drug discovery, cell therapy and regenerative medicine. Due to the importance of iPSCs over the past decade, various studies have focused on finding a safe and efficient gene delivery system to introduce reprogramming factors (RFs) into somatic cells, particularly for clinical applications. However, generated iPSCs from any source must undergo genomic, epigenomic, and functional characterizations to ensure they are free of somatic memories and safe for clinical application. In this review, almost all the employed cargos for delivering RFs into somatic cells were investigated, focusing on biological, chemical, and physical approaches to promote reprogramming efficiency and reduce exogenous factors. Moreover, the advantages and disadvantages of each approach were highlighted and cutting-edge technologies in iPSCs technology were also discussed. This review aims to provide a comprehensive overview discussing how to improve the efficiency and quality of iPSCs production.

Generation and validation of a Leber Congenital Amaurosis, Type 12 patient-specific iPSC line (LVPEIi006-B) with a splice-site mutation in RD3 and an isogenic mutation-corrected iPSC line (LVPEIi006-B-1)

Leber congenital amaurosis, Type 12 is an early onset, autosomal recessive retinal disease caused by mutations in RD3. We report the generation of a patient-specific iPSC line (LVPEIi006-B), using Sendai viral vector-based reprogramming approach and an isogenic, mutation-corrected iPSC line (LVPEIi006-B-1), using an en31FnCas9-based adenine base editor (ABE) system. Both lines were clonally expanded and genotyped to confirm the presence of patient-specific mutation and desired base correction in the edited line. Both lines maintained their stemness, pluripotency, genomic integrity and could differentiate into retinal organoids. The mutation-corrected, heterozygous iPSC-derived retinal organoids displayed a partial restoration of normal RD3 mRNA splicing.

Application of induced pluripotent stem cells in the conservation of endangered animals

The accelerating biodiversity crisis urgently demands innovative approaches that transcend traditional conservation strategies, which are often constrained by genetic bottlenecks and disease risks. Induced pluripotent stem cells (iPSCs) technology emerges as a transformative solution, enabling non-invasive genetic preservation and multi-pathway species recovery. This review synthesizes advances in reprogramming somatic cells from endangered species into iPSCs through integration-free strategies, such as mRNA, Sendai virus, episomal systems, adenoviruses and chemical induction, thereby reducing genomic instability. We highlight breakthroughs in differentiating iPSCs into functional gametes for assisted reproduction and blastoids formation for embryonic reconstruction, circumventing donor oocyte dependency and genetic homogeneity risks. Despite challenges in lineage specification and epigenetic fidelity, combining iPSC biobanking with ecosystem management enables large-scale genetic rescue. By combining these technologies with ethical frameworks and habitat restoration, the plasticity of cells may be transformed into population resilience, potentially redefining biodiversity conservation.

An antisense oligonucleotide-based strategy to ameliorate cognitive dysfunction in the 22q11.2 Deletion Syndrome

Adults and children with the 22q11.2 Deletion Syndrome demonstrate cognitive, social, and emotional impairments and high risk for schizophrenia. Work in mouse model of the 22q11.2 deletion provided compelling evidence for abnormal expression and processing of microRNAs. A major transcriptional effect of the microRNA dysregulation is upregulation of Emc10, a component of the ER membrane complex, which promotes membrane insertion of a subset of polytopic and tail-anchored membrane proteins. We previously uncovered a key contribution of EMC10 in mediating the behavioral phenotypes observed in 22q11.2 deletion mouse models. Here, we show that expression and processing of miRNAs is abnormal and EMC10 expression is elevated in neurons derived from 22q11.2 deletion carriers. Reduction of EMC10 levels restores defects in neurite outgrowth and calcium signaling in patient neurons. Furthermore, antisense oligonucleotide administration and normalization of Emc10 in the adult mouse brain not only alleviates cognitive deficits in social and spatial memory but remarkably sustains these improvements for over 2 months post-injection, indicating its therapeutic potential. Broadly, our study integrates findings from both animal models and human neurons to elucidate the translational potential of modulating EMC10 levels and downstream targets as a specific venue to ameliorate disease progression in 22q11.2 Deletion Syndrome.

Recombinant Sendai Virus Vectors as Novel Vaccine Candidates Against Animal Viruses

Vaccination plays a pivotal role in the control and prevention of animal infectious diseases. However, no efficient and safe universal vaccines are currently registered for major pathogens such as influenza A virus, foot-and-mouth disease virus (FMDV), simian immunodeficiency virus (SIV), and small ruminant lentiviruses (SRLV). Here, we review the development of Sendai virus (SeV) vectors as a promising vaccine platform for animal diseases. Recombinant SeV vectors (rSeVv) possess several key features that make them highly suitable for developing vaccination strategies: (1) SeV has exclusively cytoplasmic replication cycle, therefore incapable of transforming host cells by integrating into the cellular genome, (2) rSeVv can accommodate large foreign gene/s inserts (~5 kb) with strong but adjustable transgene expression, (3) can be propagated to high titers in both embryonated chicken eggs and mammalian cell lines, (4) exhibits potent infectivity across a broad range of mammalian cells from different animals species, (5) undergo transient replication in the upper and lower respiratory tracts of non-natural hosts, (6) has not been associated with disease in pigs, non-humans primates, and small ruminants, ensuring a favorable safety profile, and (7) induce a robust innate and cellular immune responses. Preclinical and clinical studies using rSeVv-based vaccines against influenza A virus, FMDV, SIV, and SRLV have yielded promising results. Therefore, this review highlights the potential of rSeVv-based vaccine platforms as a valuable strategy for combating animal viruses.

Identifying Age-Modulating Compounds Using a Novel Computational Framework for Evaluating Transcriptional Age

The differentiation of human pluripotent stem cells (hPSCs) provides access to a wide range of cell types and tissues. However, hPSC-derived lineages typically represent a fetal stage of development, and methods to expedite the transition to an aged identity to improve modeling of late-onset disease are limited. In this study, we introduce RNAge, a transcriptome-based computational platform designed to enable the evaluation of an induced aging or a rejuvenated state. We validated this approach across independent datasets spanning different tissues and species, and show that it can be used to evaluate the effectiveness of existing age-retaining or age-modulating interventions. We also used RNAge to perform an in silico compound screen using the LINCS L1000 dataset. This approach led to the identification and experimental confirmation of several novel compounds capable of inducing aging or rejuvenation in primary fibroblasts or hPSC-derived neurons. Additionally, we observed that applying this novel induced aging strategy to an hPSC model of Alzheimer's disease (AD) accelerated neurodegeneration in a genotype-specific manner. Our study offers a robust method for quantifying age-related manipulations and unveils compounds that significantly broaden the toolkit for age-modifying strategies in hPSC-derived lineages.

Footprint-free induced pluripotent stem cells can be successfully differentiated into mesenchymal stromal cells in the feline model

BACKGROUND

Induced pluripotent stem cells (iPSCs) can propagate indefinitely and give rise to every other cell type, rendering them invaluable for disease modelling, drug development research, and usage in regenerative medicine. While feline iPSCs have been described, there are currently no reports on generating genome integration (footprint)-free iPSCs from domestic cats. Therefore, the objective of this study was to generate feline iPSCs from fetal fibroblasts using non-integrative Sendai virus (SeV) vectors carrying human transcription factors. Moreover, these iPSCs were differentiated into mesenchymal stromal cells (MSCs), which can be used as an alternative to tissue-derived MSCs.

METHODS

Feline fetal fibroblasts were transduced with CytoTune-iPS 2.0 Sendai Reprogramming vectors at recommended multiplicity of infections (MOI) and cultured for about 6 days. At 7 days post transduction cells were dissociated, replated on inactivated feeder cells and maintained in iPSC medium for 28 days with daily medium change. Emerging iPSC colonies were mechanically passaged and transferred to fresh feeder cells and further passaged every 6-8 days. Four feline iPSC lines were generated, with two selected for further in-depth characterization. Feline iPSCs were then differentiated into MSCs using a serial plating strategy and an inhibitor of the transforming growth factor-β (TGF-β) type I receptor.

RESULTS

Feline iPSCs exhibited characteristic colony morphology, high nuclear-to-cytoplasmic ratio, positive alkaline phosphatase activity, and expressed feline OCT4, SOX2, and Nanog homeobox (NANOG) stem cell markers. Expression of SeV-derived transgenes decreased during passaging to be eventually lost from the host cells and feline iPSCs could be stably maintained for over 35 passages. Feline iPSCs differentiated into embryoid bodies in vitro and did not form fully differentiated teratomas; instead, they generated in vivo masses containing mesodermal tissue derivatives when injected into immunodeficient mice. Feline iPSC-derived MSCs were plastic adherent, displayed MSC-like morphology, expressed MSC-specific surface markers, and differentiated into cells from the mesodermal lineage in vitro. RNA deep sequencing identified 1,189 differentially expressed genes in feline iPSC-derived MSCs compared to feline iPSCs.

CONCLUSION

We demonstrated the generation of footprint-free iPSCs from domestic cats and their directed differentiation potential towards MSCs. These SeV-derived feline iPSCs and iPSC-derived MSCs will provide valuable models to study feline diseases and explore novel therapeutic strategies and can serve as translational models for human health, leading to increased knowledge on disease pathogenesis and improved therapeutic interventions.

Generation and purification of iPSC-derived cardiomyocytes for clinical applications

BACKGROUND

Over the past decade, the field of cell therapy has rapidly expanded with the aim to replace and repair damaged cells and/or tissue. Depending on the disease many different cell types can be used as part of such a therapy. Here we focused on the potential treatment of myocardial infarction, where currently available treatment options are not able to regenerate the loss of healthy heart tissue.

METHOD

We generated good manufacturing practice (GMP)-compatible cardiomyocytes (iCMs) from transgene- and xenofree induced pluripotent stem cells (iPSCs) that can be seamless adapted for clinical applications. Further protocols were established for replating and freezing/thawing iCMs under xenofree conditions.

RESULTS

iCMs showed a cardiac phenotype, with the expression of specific cardiac markers and absence of pluripotency markers at RNA and protein level. To ensure a pure iCMs population for in vivo applications, we minimized risks of iPSC contamination using RNA-switch technology to ensure safety.

CONCLUSION

We describe the generation and further processing of xeno- and transgene-free iCMs. The use of GMP-compliant differentiation protocols ab initio facilitates the clinical translation of this project in later stages.

Inhibition of PRC2 enables self-renewal of blastoid-competent naive pluripotent stem cells from chimpanzee

Naive pluripotent stem cells (PSCs) are counterparts of early epiblast in the mammalian embryo. Mouse and human naive PSCs differ in self-renewal requirements and extraembryonic lineage potency. Here, we investigated the generation of chimpanzee naive PSCs. Colonies generated by resetting or reprogramming failed to propagate. We discovered that self-renewal is enabled by inhibition of Polycomb repressive complex 2 (PRC2). Expanded cells show global transcriptome proximity to human naive PSCs and embryo pre-implantation epiblast, with shared expression of a subset of pluripotency transcription factors. Chimpanzee naive PSCs can transition to multilineage competence or can differentiate into trophectoderm and hypoblast, forming tri-lineage blastoids. They thus provide a higher primate comparative model for studying pluripotency and early embryogenesis. Genetic deletions confirm that PRC2 mediates growth arrest. Further, inhibition of PRC2 overcomes a roadblock to feeder-free propagation of human naive PSCs. Therefore, excess deposition of chromatin modification H3K27me3 is an unexpected barrier to naive PSC self-renewal.

Induced Pluripotent Stem Cell-Derived Exosomes Promote Peripheral Nerve Regeneration in a Rat Sciatic Nerve Crush Injury Model: A Safety and Efficacy Study

Peripheral nerve injury (PNI) remains a significant clinical challenge, often leading to long-term functional impairment. Despite advances in therapies, current repair strategies offer unsatisfactory clinical outcomes. Exosomes derived from induced pluripotent stem cells (iPSC-Exos) have emerged as a promising therapeutic approach in regenerative medicine. This study assesses the efficacy and safety of iPSC-Exos in a rat model of sciatic nerve crush injury. Briefly, iPSCs were generated from peripheral blood mononuclear cells (PBMCs) of healthy donors using Sendai virus vectors and validated for pluripotency. iPSC-Exos were characterized and injected at the injury site. Functional recovery was assessed through gait analysis, grip strength, and pain response. Histological and molecular analyses were used to examine axonal regeneration, myelination, Schwann cell (SC) activation, angiogenesis, and changes in gene expression. iPSC-Exos were efficiently internalized by SC, promoting their proliferation. No adverse effects were observed between groups on body weight, organ histology, or hematological parameters. iPSC-Exos injection significantly enhanced nerve regeneration, muscle preservation, and vascularization, with RNA sequencing revealing activation of PI3K-AKT and focal adhesion pathways. These findings support iPSC-Exos as a safe and effective non-cell-based therapy for PNIs, highlighting their potential for clinical applications in regenerative medicine.

Increased mitochondrial mutation heteroplasmy induces aging phenotypes in pluripotent stem cells and their differentiated progeny

The mitochondrial genome (mtDNA) is an important source of inherited extranuclear variation. Clonal increases in mtDNA mutation heteroplasmy have been implicated in aging and disease, although the impact of this shift on cell function is challenging to assess. Reprogramming to pluripotency affects mtDNA mutation heteroplasmy. We reprogrammed three human fibroblast lines with known heteroplasmy for deleterious mtDNA point or deletion mutations. Quantification of mutation heteroplasmy in the resulting 76 induced pluripotent stem cell (iPSC) clones yielded a bimodal distribution, creating three sets of clones with high levels or absent mutation heteroplasmy with matched nuclear genomes. iPSC clones with elevated deletion mutation heteroplasmy show altered growth dynamics, which persist in iPSC-derived progenitor cells. We identify transcriptomic and metabolic shifts consistent with increased investment in neutral lipid synthesis as well as increased epigenetic age in high mtDNA deletion mutation iPSC, consistent with changes occurring in cellular aging. Together, these data demonstrate that high mtDNA mutation heteroplasmy induces changes occurring in cellular aging.

Human iPSC Reprogramming Success: The Impact of Approaches and Source Materials

Since their discovery, human induced pluripotent stem cells (hiPSCs) have been instrumental in biomedical research, particularly in the fields of disease modelling, drug screening and regenerative therapies. Their use has significantly increased over recent years driven by the ability of hiPSCs to provide differentiated cell models without requiring embryonic stem cells. Furthermore, the transition from integrating to non-integrating reprogramming methodologies has contributed to the increase in utilisation. This shift minimises the risk of genomic alterations, enhancing the safety and reliability of hiPSCs. However, the factors that contribute to reprogramming success are still not well understood. In this study, we conducted a comparative analysis of the most prevalent non-integrating reprogramming methods across a range of starting source materials to assess their impact on reprogramming success rates. We found that while source material does not significantly impact success rates, the Sendai virus reprogramming method yields significantly higher success rates relative to the episomal reprogramming method. Our findings offer important insights from a biobanking perspective, for which long-term reliability, integrity and reproducibility of hiPSCs are crucial.

Induced Pluripotent Stem Cells in Birds: Opportunities and Challenges for Science and Agriculture

The only cells in an organism that could do any other sort of cell until 2006 (except sperm or egg) were known as embryonic stem cells, ESC [...].

Structural and functional alterations of neurons derived from sporadic Alzheimer's disease hiPSCs are associated with downregulation of the LIMK1-cofilin axis

BACKGROUND

Alzheimer's Disease (AD) is a neurodegenerative disorder characterized by the accumulation of pathological proteins and synaptic dysfunction. This study aims to investigate the molecular and functional differences between human induced pluripotent stem cells (hiPSCs) derived from patients with sporadic AD (sAD) and age-matched controls (healthy subjects, HS), focusing on their neuronal differentiation and synaptic properties in order to better understand the cellular and molecular mechanisms underlying AD pathology.

METHODS

Skin fibroblasts from sAD patients (n = 5) and HS subjects (n = 5) were reprogrammed into hiPSCs using non-integrating Sendai virus vectors. Through karyotyping, we assessed pluripotency markers (OCT4, SOX2, TRA-1-60) and genomic integrity. Neuronal differentiation was evaluated by immunostaining for MAP2 and NEUN. Electrophysiological properties were measured using whole-cell patch-clamp, while protein expression of Aβ, phosphorylated tau, Synapsin-1, Synaptophysin, PSD95, and GluA1 was quantified by western blot. We then focused on PAK1-LIMK1-Cofilin signaling, which plays a key role in regulating synaptic structure and function, both of which are disrupted in neurodegenerative diseases such as AD.

RESULTS

sAD and HS hiPSCs displayed similar stemness features and genomic stability. However, they differed in neuronal differentiation and function. sAD-derived neurons (sAD-hNs) displayed increased levels of AD-related proteins, including Aβ and phosphorylated tau. Electrophysiological analyses revealed that while both sAD- and HS-hNs generated action potentials, sAD-hNs exhibited decreased spontaneous synaptic activity. Significant reductions in the expression of synaptic proteins such as Synapsin-1, Synaptophysin, PSD95, and GluA1 were found in sAD-hNs, which are also characterized by reduced neurite length, indicating impaired differentiation. Notably, sAD-hNs demonstrated a marked reduction in LIMK1 phosphorylation, which could be the underlying cause for the changes in cytoskeletal dynamics that we found, leading to the morphological and functional modifications observed in sAD-hNs. To further investigate the involvement of the LIMK1 pathway in the morphological and functional changes observed in sAD neurons, we conducted perturbation experiments using the specific LIMK1 inhibitor, BMS-5. Neurons obtained from healthy subjects treated with the inhibitor showed similar morphological changes to those observed in sAD neurons, confirming that LIMK1 activity is crucial for maintaining normal neuronal structure. Furthermore, administration of the inhibitor to sAD neurons did not exacerbate the morphological alterations, suggesting that LIMK1 activity is already compromised in these cells.

CONCLUSION

Our findings demonstrate that although sAD- and HS-hiPSCs are similar in their stemness and genomic stability, sAD-hNs exhibit distinct functional and structural anomalies mirroring AD pathology. These anomalies include synaptic dysfunction, altered cytoskeletal organization, and accumulation of AD-related proteins. Our study underscores the usefulness of hiPSCs in modeling AD and provides insights into the disease's molecular underpinnings, thus highlighting potential therapeutic targets.

Modulation of the JAK2-STAT3 pathway promotes expansion and maturation of human iPSCs-derived myogenic progenitor cells

Generation of in vitro induced pluripotent cells (hiPSCs)-derived skeletal muscle progenitor cells (SMPCs) holds great promise for regenerative medicine for skeletal muscle wasting diseases, as for example Duchenne Muscular Dystrophy (DMD). Multiple approaches, involving ectopic expression of key regulatory myogenic genes or small molecules cocktails, have been described by different groups to obtain SMPC towards cell-transplantation in vivo as a therapeutic approach to skeletal muscle diseases. However, hiPSCs-derived SMPC generated using transgene-free protocols are usually obtained in a low amount and resemble a more embryonal/fetal stage of differentiation. Here we demonstrate that modulation of the JAK2/STAT3 signaling pathway during an in vitro skeletal muscle differentiation protocol, increases the yield of PAX7+ and CD54+ SMPCs and drive them to a postnatal maturation stage, in both human ES and patient-derived iPSCs. Importantly, upon removal of the inhibition from the cultures, the obtained SMPCs are able to differentiate into multinucleated myotubes in vitro. These findings reveal that modulation of the JAK2/STAT3 signaling pathway is a potential therapeutic avenue to generate SMPCs in vitro with increase potential for cell-therapy approaches.

Chemical transdifferentiation of somatic cells to neural cells: a systematic review

INTRODUCTION

Transdifferentiation is the conversion of a specific somatic cell into another cell type, bypassing a transient pluripotent state. This implies a faster method to generate cells of interest with the additional benefit of reduced tumorigenic risk for clinical use.

OBJECTIVE

We describe protocols that use small molecules as direct conversion inducers, without the need for exogenous factors, to evaluate the potential of cell transdifferentiation for pharmacological and clinical applications.

METHODS

In this systematic review, using PRISMA guidelines, we conducted a personalized search strategy in four databases (PubMed, Scopus, Embase, and Web Of Science), looking for experimental works that used exclusively small molecules for transdifferentiation of non-neural cell types into neural lineage cells.

RESULTS

We explored the main biological mechanisms involved in direct cell conversion induced by different small molecules used in 33 experimental in vitro and in vitro transdifferentiation protocols. We also summarize the main characteristics of these protocols, such as the chemical cocktails used, time for transdifferentiation, and conversion efficiency.

CONCLUSION

Small molecules-based protocols for neuronal transdifferentiation are reasonably safe, economical, accessible, and are a promising alternative for future use in regenerative medicine and pharmacology.

Generation of IPi002-A/B/C human induced pluripotent stem cell lines from MARCH amniotic fluid cells

Human induced pluripotent stem cells (hiPSCs) have become a revolutionary tool in biomedical research due to their unique in vitro properties and fate versatility. They offer insights into development or genetic disorders, facilitate drug discovery and hold promise for regenerative medicine. Here we generated three hiPSC cells - IPi002-A/B/C - from primary amniotic fluid cells (AFCs) obtained via amniocentesis for the prenatal diagnosis of MARCH syndrome: Multinucleated neurons, Anhydramnios, Renal dysplasia, Cerebellar hypoplasia, and Hydranencephaly. These AFCs underwent reprogramming through non-integrative viral transduction and the resulting hiPSCs exhibited normal karyotype and expressed typical pluripotency markers.

Complete suspension culture of human induced pluripotent stem cells supplemented with suppressors of spontaneous differentiation

Human induced pluripotent stem cells (hiPSCs) are promising resources for producing various types of tissues in regenerative medicine; however, the improvement in a scalable culture system that can precisely control the cellular status of hiPSCs is needed. Utilizing suspension culture without microcarriers or special materials allows for massive production, automation, cost-effectiveness, and safety assurance in industrialized regenerative medicine. Here, we found that hiPSCs cultured in suspension conditions with continuous agitation without microcarriers or extracellular matrix components were more prone to spontaneous differentiation than those cultured in conventional adherent conditions. Adding PKCβ and Wnt signaling pathway inhibitors in the suspension conditions suppressed the spontaneous differentiation of hiPSCs into ectoderm and mesendoderm, respectively. In these conditions, we successfully completed the culture processes of hiPSCs, including the generation of hiPSCs from peripheral blood mononuclear cells with the expansion of bulk population and single-cell sorted clones, long-term culture with robust self-renewal characteristics, single-cell cloning, direct cryopreservation from suspension culture and their successful recovery, and efficient mass production of a clinical-grade hiPSC line. Our results demonstrate that precise control of the cellular status in suspension culture conditions paves the way for their stable and automated clinical application.

The Role of Human-Induced Pluripotent Stem Cells in Studying Cardiac Channelopathies

Cardiac channelopathies are inherited diseases that increase the risk of sudden cardiac death. While different genes have been associated with inherited channelopathies, there are still subtypes, e.g., catecholaminergic polymorphic ventricular tachycardia and Brugada syndrome, where the genetic cause remains unknown. Various models, including animal models, heterologous expression systems, and the human-induced pluripotent stem-cell-derived cardiomyocytes (hiPSCs-CMs) model, have been used to study the pathophysiological mechanisms of channelopathies. Recently, researchers have focused on using hiPSCs-CMs to understand the genotype-phenotype correlation and screen drugs. By combining innovative techniques such as Clustered Regularly Interspaced Short Palindromic Repeats/Clustered Regularly Interspaced Short Palindromic Repeats associated protein 9 (CRISPR/Cas9)-mediated genome editing, and three-dimensional (3D) engineered heart tissues, we can gain new insights into the pathophysiological mechanisms of channelopathies. This approach holds promise for improving personalized drug treatment. This review highlights the role of hiPSCs-CMs in understanding the pathomechanism of Brugada syndrome and catecholaminergic polymorphic ventricular tachycardia and how these models can be utilized for drug screening.

Probing the biological consequences of a previously undescribed de novo mutation of ZMYND11 in a schizophrenia patient by CRISPR genome editing and induced pluripotent stem cell based in vitro disease-modeling

BACKGROUND

Schizophrenia (SCZ) is a severe neuropsychiatric disorder of complex, poorly understood etiology, associated with both genetic and environmental factors. De novo mutations (DNMs) represent a new source of genetic variation in SCZ, however, in most cases their biological significance remains unclear. We sought to investigate molecular disease pathways connected to DNMs in SCZ by combining human induced pluripotent stem cell (hiPSC) based disease modeling and CRISPR-based genome editing.

METHODS

We selected a SCZ case-parent trio with the case individual carrying a potentially disease causing 1495C > T nonsense DNM in the zinc finger MYND domain-containing protein 11 (ZMYND11), a gene implicated in biological processes relevant for SCZ. In the patient-derived hiPSC line the mutation was corrected using CRISPR, while monoallelic or biallelic frameshift mutations were introduced into a control hiPSC line. Isogenic cell lines were differentiated into hippocampal neuronal progenitor cells (NPCs) and functionally active dentate gyrus granule cells (DGGCs). Immunofluorescence microscopy and RNA sequencing were used to test for morphological and transcriptomic differences at NPC and DGCC stages. Functionality of neurons was investigated using calcium-imaging and multi-electrode array measurements.

RESULTS

Morphology in the mutant hippocampal NPCs and neurons was preserved, however, we detected significant transcriptomic and functional alterations. RNA sequencing showed massive upregulation of neuronal differentiation genes, and downregulation of cell adhesion genes. Decreased reactivity to glutamate was demonstrated by calcium-imaging.

CONCLUSIONS

Our findings lend support to the involvement of glutamatergic dysregulation in the pathogenesis of SCZ. This approach represents a powerful model system for precision psychiatry and pharmacological research.

Investigating Inherited Heart Diseases Using Human Induced Pluripotent Stem Cell-Based Models

Inherited heart diseases (IHDs) are caused by genetic mutations that disrupt the physiological structure and function of the heart. Understanding the mechanisms behind these diseases is crucial for developing personalised interventions in cardiovascular medicine. Development of induced pluripotent stem cells, which can then be differentiated to any nucleated adult cell type, has enabled the creation of personalised single-cell and multicellular models, providing unprecedented insights into the pathophysiology of IHDs. This review provides a comprehensive overview of recent advancements in human iPSC models used to dissect the molecular and genetic underpinnings of common IHDs. We examine multicellular models and tissue engineering approaches, such as cardiac organoids, engineered heart tissue, and multicellular co-culture systems, which simulate complex intercellular interactions within heart tissue. Recent advancements in stem cell models offer a more physiologically relevant platform to study disease mechanisms, enabling researchers to observe cellular interactions, study disease progression, and identify therapeutic strategies. By leveraging these innovative models, we can gain deeper insights into the molecular and cellular mechanisms underlying IHDs, ultimately paving the way for more effective diagnostic and therapeutic strategies.

Generation of induced pluripotent stem cells from an HLA-B27 positive ankylosing spondylitis patient with syndesmophyte formation

Human leukocyte antigen (HLA)-B27 is the genetic marker for ankylosing spondylitis (AS). Here, we generated induced pluripotent stem cells (iPSCs) from peripheral blood mononuclear cells of a male AS patient carrying HLA-B27 with syndesmophyte formation by using the Sendai-virus delivery system. The resulting iPSCs had a normal karyotype, expressed pluripotent markers, and could differentiate into three germ layers. This cellular model will provide a platform for studying pathological mechanisms of new bone formation in HLA-B27 positive AS patients.

Manipulating cell fate through reprogramming: approaches and applications

Cellular plasticity progressively declines with development and differentiation, yet these processes can be experimentally reversed by reprogramming somatic cells to induced pluripotent stem cells (iPSCs) using defined transcription factors. Advances in reprogramming technology over the past 15 years have enabled researchers to study diseases with patient-specific iPSCs, gain fundamental insights into how cell identity is maintained, recapitulate early stages of embryogenesis using various embryo models, and reverse aspects of aging in cultured cells and animals. Here, we review and compare currently available reprogramming approaches, including transcription factor-based methods and small molecule-based approaches, to derive pluripotent cells characteristic of early embryos. Additionally, we discuss our current understanding of mechanisms that resist reprogramming and their role in cell identity maintenance. Finally, we review recent efforts to rejuvenate cells and tissues with reprogramming factors, as well as the application of iPSCs in deriving novel embryo models to study pre-implantation development.

In vitro generation of trophoblast like stem cells from goat pluripotent stem cells

Since the first mouse induced pluripotent stem cells (iPSCs) was derived, the in vitro culture of domestic iPSCs functionally and molecularly comparable with mouse iPSCs has been a challenge. Here, we established dairy goat iPSCs (giPSCs) from goat ear fibroblast cells with mouse iPSCs morphology, the expression of pluripotent markers and differentiation ability in vitro delivered by piggyBac transposon with nine Dox-inducible exogenous reprogramming factors. These reprogramming factors were bOMSK (bovine OCT4, CMYC, SOX2, and KLF4), pNhL (porcine NANOG and human LIN28), hRL (human RARG and LRH1), and SV40 Large T. Notably, AF-giPSCs (induced in activin A and bFGF condition) were capable of differentiation in embryoid bodies in vitro and could contribute to interspecies chimerism in mouse E6.5 embryos in vitro, demonstrating that AF-giPSCs have the developmental capability to generate some embryonic cell lineages. Moreover, Wnt/β-catenin signaling has an important role in driving goat induced trophoblast-like stem cells (giTLSCs) from Dox-independent giPSCs. This study will support further establishment of the stable giPSC lines without any integration of exogenous genes.

Challenges of therapeutic applications and regenerative capacities of urine based stem cells in oral, and maxillofacial reconstruction

Urine-derived stem cells (USCs) have gained the attention of researchers in the biomedical field in the past few years . Regarding the several varieties of cells that have been used for this purpose, USCs have demonstrated mesenchymal stem cell-like properties, such as differentiation and immunomodulation. Furthermore, they could be differentiated into several lineages. This is very interesting for regenerative techniques based on cell therapy. This review will embark on describing their separation, and profiling. We will specifically describe the USCs characteristics, in addition to their differentiation potential. Then, we will introduce and explore the primary uses of USCs. These involve thier utilization as a platform to produce stem cells, however, we shall concentrate on the utilization of USCs for therapeutic, and regenerative orofacial applications, providing an in-depth evaluation of this purpose. The final portion will address the limitations and challenges of their implementation in regenerative dentistry.

Induced pluripotent stem cells derived renal tubular cells from a patient with pseudohypoparathyroidism and its response to parathyroid hormone stimulation

INTRODUCTION

Creating induced pluripotent stem cells (iPSCs) from somatic cells of patients with genetic diseases offers a pathway to generate disease-specific iPSCs carrying genetic markers. Differentiating these iPSCs into renal tubular cells can aid in understanding the pathophysiology of rare inherited renal tubular diseases through cellular experiments.

MATERIALS AND METHODS

Two Japanese patients with Pseudohypoparathyroidism (PHP), a 49-year-old woman and a 71-year-old man, were studied. iPSC-derived tubular cells were established from their peripheral blood mononuclear cells (PBMCs). We examined changes in intracellular and extracellular cyclic adenosine monophosphate (cAMP) levels in these cells in response to parathyroid hormone (PTH) stimulation.

RESULTS

Renal tubular cells, differentiated from iPSCs of a healthy control (648A1), showed a PTH-dependent increase in both intracellular and extracellular cAMP levels. However, the renal tubular cells derived from the PHP patients' iPSCs showed inconsistent changes in cAMP levels upon PTH exposure.

CONCLUSION

We successfully created disease-specific iPSCs from PHP patients' PBMCs, differentiated them into tubular cells, and replicated the distinctive response of the disease to PTH in vitro. This approach could enhance our understanding of the pathophysiology of inherited renal tubular diseases and contribute to developing effective treatments.

Induced pluripotent stem cell models as a tool to investigate and test fluid biomarkers in Alzheimer's disease and frontotemporal dementia

Neurodegenerative diseases are increasing in prevalence and comprise a large socioeconomic burden on patients and their caretakers. The need for effective therapies and avenues for disease prevention and monitoring is of paramount importance. Fluid biomarkers for neurodegenerative diseases have gained a variety of uses, including informing participant selection for clinical trials, lending confidence to clinical diagnosis and disease staging, determining prognosis, and monitoring therapeutic response. Their role is expected to grow as disease-modifying therapies start to be available to a broader range of patients and as prevention strategies become established. Many of the underlying molecular mechanisms of currently used biomarkers are incompletely understood. Animal models and in vitro systems using cell lines have been extensively employed but face important translatability limitations. Induced pluripotent stem cell (iPSC) technology, where a theoretically unlimited range of cell types can be reprogrammed from peripheral cells sampled from patients or healthy individuals, has gained prominence over the last decade. It is a promising avenue to study physiological and pathological biomarker function and response to experimental therapeutics. Such systems are amenable to high-throughput drug screening or multiomics readouts such as transcriptomics, lipidomics, and proteomics for biomarker discovery, investigation, and validation. The present review describes the current state of biomarkers in the clinical context of neurodegenerative diseases, with a focus on Alzheimer's disease and frontotemporal dementia. We include a discussion of how iPSC models have been used to investigate and test biomarkers such as amyloid-β, phosphorylated tau, neurofilament light chain or complement proteins, and even nominate novel biomarkers. We discuss the limitations of current iPSC methods, mentioning alternatives such as coculture systems and three-dimensional organoids which address some of these concerns. Finally, we propose exciting prospects for stem cell transplantation paradigms using animal models as a preclinical tool to study biomarkers in the in vivo context.

Comparison of the calcium signaling alterations in GABA-ergic medium spiny neurons produced from iPSCs of different origins

Disease models based on induced pluripotent stem cells (iPSCs) are in high demand because of their physiological adequacy and well-reproducibility of the pathological phenotype. Nowadays, the most common approach to generate iPSCs is the reprogramming of somatic cells using vectors based on lentivirus or Sendai virus. We have previously shown impairments of calcium signaling including store-operated calcium entry in Huntington's disease-specific iPSCs-based GABA-ergic medium spiny neurons. However, different approaches for iPSCs generation make it difficult to compare the models since the mechanism of reprogramming may influence the electrophysiological properties of the terminally differentiated neurons. Here, we have studied the features of calcium homeostasis in GABA-ergic medium spiny neurons differentiated from iPSCs obtained from fibroblasts of the same donor using different methods. Our data demonstrated that there were no significant differences neither in calcium influx through the store-operated channels, nor in the levels of proteins activating this type of calcium entry in neurons differentiated from iPSCs generated with lenti- and Sendai viruses-based approaches. We also found no differences in voltage-gated calcium entry for these neurons. Thus, we clearly showed that various methods of cell reprogramming result in similar deregulations in neuronal calcium signaling which substantiates the ability to combine the experimental data on functional studies of ion channels in models based on iPSCs obtained by different methods and expands the prospects for the use of biobanking.

Stem cell-based therapy for fibrotic diseases: mechanisms and pathways

Fibrosis is a pathological process, that could result in permanent scarring and impairment of the physiological function of the affected organ; this condition which is categorized under the term organ failure could affect various organs in different situations. The involvement of the major organs, such as the lungs, liver, kidney, heart, and skin, is associated with a high rate of morbidity and mortality across the world. Fibrotic disorders encompass a broad range of complications and could be traced to various illnesses and impairments; these could range from simple skin scars with beauty issues to severe rheumatologic or inflammatory disorders such as systemic sclerosis as well as idiopathic pulmonary fibrosis. Besides, the overactivation of immune responses during any inflammatory condition causing tissue damage could contribute to the pathogenic fibrotic events accompanying the healing response; for instance, the inflammation resulting from tissue engraftment could cause the formation of fibrotic scars in the grafted tissue, even in cases where the immune system deals with hard to clear infections, fibrotic scars could follow and cause severe adverse effects. A good example of such a complication is post-Covid19 lung fibrosis which could impair the life of the affected individuals with extensive lung involvement. However, effective therapies that halt or slow down the progression of fibrosis are missing in the current clinical settings. Considering the immunomodulatory and regenerative potential of distinct stem cell types, their application as an anti-fibrotic agent, capable of attenuating tissue fibrosis has been investigated by many researchers. Although the majority of the studies addressing the anti-fibrotic effects of stem cells indicated their potent capabilities, the underlying mechanisms, and pathways by which these cells could impact fibrotic processes remain poorly understood. Here, we first, review the properties of various stem cell types utilized so far as anti-fibrotic treatments and discuss the challenges and limitations associated with their applications in clinical settings; then, we will summarize the general and organ-specific mechanisms and pathways contributing to tissue fibrosis; finally, we will describe the mechanisms and pathways considered to be employed by distinct stem cell types for exerting anti-fibrotic events.

Osteogenic Differentiation Potential of iMSCs on GelMA-BG-MWCNT Nanocomposite Hydrogels

The ability of bone biomaterials to promote osteogenic differentiation is crucial for the repair and regeneration of osseous tissue. The development of a temporary bone substitute is of major importance in enhancing the growth and differentiation of human-derived stem cells into an osteogenic lineage. In this study, nanocomposite hydrogels composed of gelatin methacryloyl (GelMA), bioactive glass (BG), and multiwall carbon nanotubes (MWCNT) were developed to create a bone biomaterial that mimics the structural and electrically conductive nature of bone that can promote the differentiation of human-derived stem cells. GelMA-BG-MWCNT nanocomposite hydrogels supported mesenchymal stem cells derived from human induced pluripotent stem cells, hereinafter named iMSCs. Cell adhesion was improved upon coating nanocomposite hydrogels with fibronectin and was further enhanced when seeding pre-differentiated iMSCs. Osteogenic differentiation and mature mineralization were promoted in GelMA-BG-MWCNT nanocomposite hydrogels and were most evidently observed in the 70-30-2 hydrogels, which could be due to the stiff topography characteristic from the addition of MWCNT. Overall, the results of this study showed that GelMA-BG-MWCNT nanocomposite hydrogels coated with fibronectin possessed a favorable environment in which pre-differentiated iMSCs could better attach, proliferate, and further mature into an osteogenic lineage, which was crucial for the repair and regeneration of bone.

Evaluation of the impact of iPSC differentiation protocols on transcriptomic signatures

Human induced pluripotent stem cells (iPSC) have the potential to produce desired target cell types in vitro and allow for the high-throughput screening of drugs/chemicals at population level thereby minimising the cost of drug discovery and drug withdrawals after clinical trials. There is a substantial need for the characterisation of the iPSC derived models to better understand and utilise them for toxicological relevant applications. In our study, iPSC (SBAD2 or SBAD3 lines obtained from StemBANCC project) were differentiated towards toxicologically relevant cell types: alveolar macrophages, brain capillary endothelial cells, brain cells, endothelial cells, hepatocytes, lung airway epithelium, monocytes, podocytes and renal proximal tubular cells. A targeted transcriptomic approach was employed to understand the effects of differentiation protocols on these cell types. Pearson correlation and principal component analysis (PCA) separated most of the intended target cell types and undifferentiated iPSC models as distinct groups with a high correlation among replicates from the same model. Based on PCA, the intended target cell types could also be separated into the three germ layer groups (ectoderm, endoderm and mesoderm). Differential expression analysis (DESeq2) presented the upregulated genes in each intended target cell types that allowed the evaluation of the differentiation to certain degree and the selection of key differentiation markers. In conclusion, these data confirm the versatile use of iPSC differentiated cell types as standardizable and relevant model systems for in vitro toxicology.

A comprehensive review of iPS cell line-based disease modelling of the polyglutamine spinocerebellar ataxias 2 and 3: a focus on the research outcomes

Spinocerebellar ataxias (SCAs) are a rare autosomal dominant neurodegenerative disorder. To date, approximately 50 different subtypes of SCAs have been characterized. The prevalent types of SCAs are usually of PolyQ origin, wherein the disease pathology is a consequence of multiple glutamine residues being encoded onto the disease proteins, causing expansions. SCAs 2 and 3 are the most frequently diagnosed subtypes, wherein affected patients exhibit certain characteristic physiological manifestations, such as gait ataxia and dysarthria. Nevertheless, other clinical signs were exclusive to these subtypes. Recently, multiple molecular diagnostic methods have been developed to identify and characterize these subtypes. Despite these advancements, the molecular pathology of SCAs remains unknown. To further understand the mechanisms involved in neurodegenerative SCAs 2 and 3, patient-derived induced pluripotent stem cell (iPSC)-based modelling is a compelling avenue to pursue. We cover the present state of iPSC-based in-vitro illness modelling of SCA subtypes 2 and 3 below, along with a list of cell lines created, and the relevance of research outcomes to personalized autologous therapy.

H1FOO-DD promotes efficiency and uniformity in reprogramming to naive pluripotency

Heterogeneity among both primed and naive pluripotent stem cell lines remains a major unresolved problem. Here we show that expressing the maternal-specific linker histone H1FOO fused to a destabilizing domain (H1FOO-DD), together with OCT4, SOX2, KLF4, and LMYC, in human somatic cells improves the quality of reprogramming to both primed and naive pluripotency. H1FOO-DD expression was associated with altered chromatin accessibility around pluripotency genes and with suppression of the innate immune response. Notably, H1FOO-DD generates naive induced pluripotent stem cells with lower variation in transcriptome and methylome among clones and a more uniform and superior differentiation potency. Furthermore, we elucidated that upregulation of FKBP1A, driven by these five factors, plays a key role in H1FOO-DD-mediated reprogramming.

Possible Strategies to Reduce the Tumorigenic Risk of Reprogrammed Normal and Cancer Cells

The reprogramming of somatic cells to pluripotent stem cells has immense potential for use in regenerating or redeveloping tissues for transplantation, and the future application of this method is one of the most important research topics in regenerative medicine. These cells are generated from normal cells, adult stem cells, or neoplastic cancer cells. They express embryonic stem cell markers, such as OCT4, SOX2, and NANOG, and can differentiate into all tissue types in adults, both in vitro and in vivo. However, tumorigenicity, immunogenicity, and heterogeneity of cell populations may hamper the use of this method in medical therapeutics. The risk of cancer formation is dependent on mutations of these stemness genes during the transformation of pluripotent stem cells to cancer cells and on the alteration of the microenvironments of stem cell niches at genetic and epigenetic levels. Recent reports have shown that the generation of induced pluripotent stem cells (iPSCs) derived from human fibroblasts could be induced using chemicals, which is a safe, easy, and clinical-grade manufacturing strategy for modifying the cell fate of human cells required for regeneration therapies. This strategy is one of the future routes for the clinical application of reprogramming therapy. Therefore, this review highlights the recent progress in research focused on decreasing the tumorigenic risk of iPSCs or iPSC-derived organoids and increasing the safety of iPSC cell preparation and their application for therapeutic benefits.

Generation of chimpanzee induced pluripotent stem cell lines for cross-species comparisons

As humans' closest living relatives, chimpanzees offer valuable insights into human evolution. However, technical and ethical limitations hinder investigations into the molecular and cellular foundations that distinguish chimpanzee and human traits. Recently, induced pluripotent stem cells (iPSCs) have emerged as a novel model for functional comparative studies and provided a non-invasive alternative for studying embryonic phenomena. In this study, we generated five new chimpanzee iPSC lines from peripheral blood cells and skin fibroblasts with SeV vectors carrying four reprogramming factors (human OCT3/4, SOX2, KLF4, and L-MYC) and characterized their pluripotency and differentiation potential. We also examined the expression of a human-specific non-coding RNA, HSTR1, which is predicted to be involved in human brain development. Our results show that the chimpanzee iPSCs possess pluripotent characteristics and can differentiate into various cell lineages. Moreover, we found that HSTR1 is expressed in human iPSCs and their neural derivatives but not in chimpanzee counterparts, supporting its possible role in human-specific brain development. As iPSCs are inherently variable due to genetic and epigenetic differences in donor cells or reprogramming procedures, it is essential to expand the number of chimpanzee iPSC lines to comprehensively capture the molecular and cellular properties representative of chimpanzees. Hence, our cells provide a valuable resource for investigating the function and regulation of human-specific transcripts such as HSTR1 and for understanding human evolution more generally.

A Simple Nonviral Method to Generate Human Induced Pluripotent Stem Cells Using SMAR DNA Vectors

Induced pluripotent stem cells (iPSCs) are a powerful tool for biomedical research, but their production presents challenges and safety concerns. Yamanaka and Takahashi revolutionised the field by demonstrating that somatic cells could be reprogrammed into pluripotent cells by overexpressing four key factors for a sufficient time. iPSCs are typically generated using viruses or virus-based methods, which have drawbacks such as vector persistence, risk of insertional mutagenesis, and oncogenesis. The application of less harmful nonviral vectors is limited as conventional plasmids cannot deliver the levels or duration of the factors necessary from a single transfection. Hence, plasmids that are most often used for reprogramming employ the potentially oncogenic Epstein-Barr nuclear antigen 1 (EBNA-1) system to ensure adequate levels and persistence of expression. In this study, we explored the use of nonviral SMAR DNA vectors to reprogram human fibroblasts into iPSCs. We show for the first time that iPSCs can be generated using nonviral plasmids without the use of EBNA-1 and that these DNA vectors can provide sufficient expression to induce pluripotency. We describe an optimised reprogramming protocol using these vectors that can produce high-quality iPSCs with comparable pluripotency and cellular function to those generated with viruses or EBNA-1 vectors.

The occurrence and development of induced pluripotent stem cells

The ectopic expression of four transcription factors, Oct3/4, Sox2, Klf4, and c-Myc (OSKM), known as "Yamanaka factors," can reprogram or stimulate the production of induced pluripotent stem cells (iPSCs). Although OSKM is still the gold standard, there are multiple ways to reprogram cells into iPSCs. In recent years, significant progress has been made in improving the efficiency of this technology. Ten years after the first report was published, human pluripotent stem cells have gradually been applied in clinical settings, including disease modeling, cell therapy, new drug development, and cell derivation. Here, we provide a review of the discovery of iPSCs and their applications in disease and development.

Generation of IPi001-A/B/C human induced pluripotent stem cell lines from healthy amniotic fluid cells

Human induced Pluripotent Stem Cells (hiPSCs) represent an invaluable source of primary cells to investigate development, establish cell and disease models, provide material for regenerative medicine and allow more physiological high-content screenings. Here, we generated three healthy hiPSC control lines - IPi001-A/B/C - from primary amniotic fluid cells (AFCs), an infrequently used source of cells, which can be readily obtained from amniocentesis for the prenatal diagnosis of numerous genetic disorders. These AFCs were reprogrammed by non-integrative viral transduction. The resulting hiPSCs displayed normal karyotype and expressed classic pluripotency hallmarks.

Modeling primitive and definitive erythropoiesis with induced pluripotent stem cells

ABSTRACT

During development, erythroid cells are produced through at least 2 distinct hematopoietic waves (primitive and definitive), generating erythroblasts with different functional characteristics. Human induced pluripotent stem cells (iPSCs) can be used as a model platform to study the development of red blood cells (RBCs) with many of the differentiation protocols after the primitive wave of hematopoiesis. Recent advances have established that definitive hematopoietic progenitors can be generated from iPSCs, creating a unique situation for comparing primitive and definitive erythrocytes derived from cell sources of identical genetic background. We generated iPSCs from healthy fetal liver (FL) cells and produced isogenic primitive or definitive RBCs which were compared directly to the FL-derived RBCs. Functional assays confirmed differences between the 2 programs, with primitive RBCs showing a reduced proliferation potential, larger cell size, lack of Duffy RBC antigen expression, and higher expression of embryonic globins. Transcriptome profiling by scRNA-seq demonstrated high similarity between FL- and iPSC-derived definitive RBCs along with very different gene expression and regulatory network patterns for primitive RBCs. In addition, iPSC lines harboring a known pathogenic mutation in the erythroid master regulator KLF1 demonstrated phenotypic changes specific to definitive RBCs. Our studies provide new insights into differences between primitive and definitive erythropoiesis and highlight the importance of ontology when using iPSCs to model genetic hematologic diseases. Beyond disease modeling, the similarity between FL- and iPSC-derived definitive RBCs expands potential applications of definitive RBCs for diagnostic and transfusion products.

Sendai virus is robust and consistent in delivering genes into human pancreatic cancer cells

Background

Pancreatic ductal adenocarcinoma (PDAC) is a highly intratumorally heterogeneous disease that includes several subtypes and is highly plastic. Effective gene delivery to all PDAC cells is essential for modulating gene expression and identifying potential gene-based therapeutic targets in PDAC. Most current gene delivery systems for pancreatic cells are optimized for islet or acinar cells. Lentiviral vectors are the current main gene delivery vectors for PDAC, but their transduction efficiencies vary depending on pancreatic cell type, and are especially poor for the classical subtype of PDAC cells from both primary tumors and cell lines.

Methods

We systemically compare transduction efficiencies of glycoprotein G of vesicular stomatitis virus (VSV-G)-pseudotyped lentiviral and Sendai viral vectors in human normal pancreatic ductal and PDAC cells.

Results

We find that the Sendai viral vector gives the most robust gene delivery efficiency regardless of PDAC cell type. Therefore, we propose using Sendai viral vectors to transduce ectopic genes into PDAC cells.

Induced Pluripotent Stem Cells in Drug Discovery and Neurodegenerative Disease Modelling

Induced pluripotent stem cells (iPSCs) are derived from reprogrammed adult somatic cells. These adult cells are manipulated in vitro to express genes and factors essential for acquiring and maintaining embryonic stem cell (ESC) properties. This technology is widely applied in many fields, and much attention has been given to developing iPSC-based disease models to validate drug discovery platforms and study the pathophysiological molecular processes underlying disease onset. Especially in neurological diseases, there is a great need for iPSC-based technological research, as these cells can be obtained from each patient and carry the individual's bulk of genetic mutations and unique properties. Moreover, iPSCs can differentiate into multiple cell types. These are essential characteristics, since the study of neurological diseases is affected by the limited access to injury sites, the need for in vitro models composed of various cell types, the complexity of reproducing the brain's anatomy, the challenges of postmortem cell culture, and ethical issues. Neurodegenerative diseases strongly impact global health due to their high incidence, symptom severity, and lack of effective therapies. Recently, analyses using disease specific, iPSC-based models confirmed the efficacy of these models for testing multiple drugs. This review summarizes the advances in iPSC technology used in disease modelling and drug testing, with a primary focus on neurodegenerative diseases, including Parkinson's and Alzheimer's diseases.

"Time Is out of Joint" in Pluripotent Stem Cells: How and Why

The circadian rhythm is necessary for the homeostasis and health of living organisms. Molecular clocks interconnected by transcription/translation feedback loops exist in most cells of the body. A puzzling exemption to this, otherwise, general biological hallmark is given by the cell physiology of pluripotent stem cells (PSCs) that lack circadian oscillations gradually acquired following their in vivo programmed differentiation. This process can be nicely phenocopied following in vitro commitment and reversed during the reprogramming of somatic cells to induce PSCs. The current understanding of how and why pluripotency is "time-uncoupled" is largely incomplete. A complex picture is emerging where the circadian core clockwork is negatively regulated in PSCs at the post-transcriptional/translational, epigenetic, and other-clock-interaction levels. Moreover, non-canonical functions of circadian core-work components in the balance between pluripotency identity and metabolic-driven cell reprogramming are emerging. This review selects and discusses results of relevant recent investigations providing major insights into this context.

Generation of three isogenic human induced pluripotent stem cell lines from normal neonate skin fibroblasts

Characterized human induced pluripotent stem cell lines are important for basic research. Here, we report the establishment of three isogenic human induced pluripotent stem cell (hiPSC) lines generated from normal neonate male skin fibroblasts. Pluripotency was induced using the integration free Sendai virus reprogramming method. The pluripotency, identity, quality, and safety of the lines were confirmed to establish characterized human induced pluripotent stem cell lines to be used as normal control cell lines in future studies.

Integration-free induced pluripotent stem cells from three endangered Southeast Asian non-human primate species

Advanced molecular and cellular technologies provide promising tools for wildlife and biodiversity conservation. Induced pluripotent stem cell (iPSC) technology offers an easily accessible and infinite source of pluripotent stem cells, and have been derived from many threatened wildlife species. This paper describes the first successful integration-free reprogramming of adult somatic cells to iPSCs, and their differentiation, from three endangered Southeast Asian primates: the Celebes Crested Macaque (Macaca nigra), the Lar Gibbon (Hylobates lar), and the Siamang (Symphalangus syndactylus). iPSCs were also generated from the Proboscis Monkey (Nasalis larvatus). Differences in mechanisms could elicit new discoveries regarding primate evolution and development. iPSCs from endangered species provides a safety net in conservation efforts and allows for sustainable sampling for research and conservation, all while providing a platform for the development of further in vitro models of disease.

hiPSC-derived cardiomyocytes as a model to study the role of small-conductance Ca2+-activated K+ (SK) ion channel variants associated with atrial fibrillation

Atrial fibrillation (AF), the most common arrhythmia, has been associated with different electrophysiological, molecular, and structural alterations in atrial cardiomyocytes. Therefore, more studies are required to elucidate the genetic and molecular basis of AF. Various genome-wide association studies (GWAS) have strongly associated different single nucleotide polymorphisms (SNPs) with AF. One of these GWAS identified the rs13376333 risk SNP as the most significant one from the 1q21 chromosomal region. The rs13376333 risk SNP is intronic to the KCNN3 gene that encodes for small conductance calcium-activated potassium channels type 3 (SK3). However, the functional electrophysiological effects of this variant are not known. SK channels represent a unique family of K+ channels, primarily regulated by cytosolic Ca2+ concentration, and different studies support their critical role in the regulation of atrial excitability and consequently in the development of arrhythmias like AF. Since different studies have shown that both upregulation and downregulation of SK3 channels can lead to arrhythmias by different mechanisms, an important goal is to elucidate whether the rs13376333 risk SNP is a gain-of-function (GoF) or a loss-of-function (LoF) variant. A better understanding of the functional consequences associated with these SNPs could influence clinical practice guidelines by improving genotype-based risk stratification and personalized treatment. Although research using native human atrial cardiomyocytes and animal models has provided useful insights, each model has its limitations. Therefore, there is a critical need to develop a human-derived model that represents human physiology more accurately than existing animal models. In this context, research with human induced pluripotent stem cells (hiPSC) and subsequent generation of cardiomyocytes derived from hiPSC (hiPSC-CMs) has revealed the underlying causes of various cardiovascular diseases and identified treatment opportunities that were not possible using in vitro or in vivo studies with animal models. Thus, the ability to generate atrial cardiomyocytes and atrial tissue derived from hiPSCs from human/patients with specific genetic diseases, incorporating novel genetic editing tools to generate isogenic controls and organelle-specific reporters, and 3D bioprinting of atrial tissue could be essential to study AF pathophysiological mechanisms. In this review, we will first give an overview of SK-channel function, its role in atrial fibrillation and outline pathophysiological mechanisms of KCNN3 risk SNPs. We will then highlight the advantages of using the hiPSC-CM model to investigate SNPs associated with AF, while addressing limitations and best practices for rigorous hiPSC studies.

Cellular models in autoinflammatory disease research

Systemic autoinflammatory diseases are a heterogeneous group of rare genetic disorders caused by dysregulation of the innate immune system. Understanding the complex mechanisms underlying these conditions is critical for developing effective treatments. Cellular models are essential for identifying new conditions and studying their pathogenesis. Traditionally, these studies have used primary cells and cell lines of disease-relevant cell types, although newer induced pluripotent stem cell (iPSC)-based models might have unique advantages. In this review, we discuss the three cellular models used in autoinflammatory disease research, their strengths and weaknesses, and their applications to inform future research in the field.

Avian iPSC Derivation to Recover Threatened Wild Species: A Comprehensive Review in Light of Well-Established Protocols

Induced pluripotent stem cells (iPSCs) were first generated by Yamanaka in 2006, revolutionizing research by overcoming limitations imposed by the use of embryonic stem cells. In terms of the conservation of endangered species, iPSC technology presents itself as a viable alternative for the manipulation of target genetics without compromising specimens. Although iPSCs have been successfully generated for various species, their application in nonmammalian species, particularly avian species, requires further in-depth investigation to cover the diversity of wild species at risk and their different protocol requirements. This study aims to provide an overview of the workflow for iPSC induction, comparing well-established protocols in humans and mice with the limited information available for avian species. Here, we discuss the somatic cell sources to be reprogrammed, genetic factors, delivery methods, enhancers, a brief history of achievements in avian iPSC derivation, the main approaches for iPSC characterization, and the future perspectives and challenges for the field. By examining the current protocols and state-of-the-art techniques employed in iPSC generation, we seek to contribute to the development of efficient and species-specific iPSC methodologies for at-risk avian species. The advancement of iPSC technology holds great promise for achieving in vitro germline competency and, consequently, addressing reproductive challenges in endangered species, providing valuable tools for basic research, bird genetic preservation and rescue, and the establishment of cryobanks for future conservation efforts.

Generation of Induced Pluripotent Stem Cells from Erythroid Progenitor Cells

Induced pluripotent stem cells (iPSCs) are generated through the reprogramming of somatic cells to an embryonic-like state by activating specific genes. They closely resemble embryonic stem cells (ESCs), in various aspects, including the expression of key stem cell genes, potency, and differentiation capabilities. iPSCs can be derived from various cell types such as fibroblasts, keratinocytes, and peripheral blood mononuclear cells (PBMCs). The ease of obtaining origin cells through non-invasive methods simplifies the generation of human iPSCs. Therefore, PBMCs are commonly preferred, with erythroid progenitor cells (EPCs) obtained through EPC enrichment being used as origin cells in this protocol. The EPC enrichment performed in this protocol not only reduces costs but also increases efficiency by enhancing the percentage of reprogrammable cells with progenitor characteristics. Human iPSCs are incredibly valuable for in vitro research, cell therapy, drug discovery, and tissue engineering. The outlined procedures below provide a general framework for inducing iPSCs from erythroid progenitor cells, pluripotency confirmation experiments, and cultivating them for downstream experiments.

Advances in Genetic Reprogramming: Prospects from Developmental Biology to Regenerative Medicine

The foundations of cell reprogramming were laid by Yamanaka and co-workers, who showed that somatic cells can be reprogrammed into pluripotent cells (induced pluripotency). Since this discovery, the field of regenerative medicine has seen advancements. For example, because they can differentiate into multiple cell types, pluripotent stem cells are considered vital components in regenerative medicine aimed at the functional restoration of damaged tissue. Despite years of research, both replacement and restoration of failed organs/ tissues have remained elusive scientific feats. However, with the inception of cell engineering and nuclear reprogramming, useful solutions have been identified to counter the need for compatible and sustainable organs. By combining the science underlying genetic engineering and nuclear reprogramming with regenerative medicine, scientists have engineered cells to make gene and stem cell therapies applicable and effective. These approaches have enabled the targeting of various pathways to reprogramme cells, i.e., make them behave in beneficial ways in a patient-specific manner. Technological advancements have clearly supported the concept and realization of regenerative medicine. Genetic engineering is used for tissue engineering and nuclear reprogramming and has led to advances in regenerative medicine. Targeted therapies and replacement of traumatized , damaged, or aged organs can be realized through genetic engineering. Furthermore, the success of these therapies has been validated through thousands of clinical trials. Scientists are currently evaluating induced tissue-specific stem cells (iTSCs), which may lead to tumour-free applications of pluripotency induction. In this review, we present state-of-the-art genetic engineering that has been used in regenerative medicine. We also focus on ways that genetic engineering and nuclear reprogramming have transformed regenerative medicine and have become unique therapeutic niches.

Genomic Engineering of Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Recent advances in patient-derived induced Pluripotent Stem Cell (iPSC) generation, improvement of cardiomyocyte-directed differentiation protocols, and the availability of new genome editing techniques have opened up new avenues for disease modeling of cardiomyopathies. Patients with cardiomyopathies often harbor a single-base substitution believed to be linked to the disease phenotype. Somatic cells derived from patients can be efficiently reprogrammed into iPSCs and subsequently engineered. The targeting of a precise mutation can be achieved by the introduction of double stranded breaks with CRISPR-Cas9 and by homology-directed repair when using a DNA donor template. This allows for the correction of a mutation in a patient iPSC line to generate an isogenic control. In addition, key mutations associated with cardiomyopathies can be introduced in an iPSC line derived from a healthy individual using the same techniques. In this chapter, we describe in detail how to engineer pluripotent stem cells to model cardiomyopathy in a dish using CRISPR-Cas9 technology.