iPSC Culture Research Articles

Creation of an Isogenic Human iPSC-Based RGC Model of Dominant Optic Atrophy Harboring the Pathogenic Variant c.1861C>T (p.Gln621Ter) in the OPA1 Gene.

Autosomal dominant optic atrophy (ADOA) is a rare progressive disease mainly caused by mutations in OPA1, a nuclear gene encoding for a mitochondrial protein that plays an essential role in mitochondrial dynamics, cell survival, oxidative phosphorylation, and mtDNA maintenance. ADOA is characterized by the degeneration of retinal ganglion cells (RGCs). This causes visual loss, which can lead to legal blindness in many cases. Nowadays, there is no effective treatment for ADOA. In this article, we have established an isogenic human RGC model for ADOA using iPSC technology and the genome editing tool CRISPR/Cas9 from a previously generated iPSC line of an ADOA plus patient harboring the pathogenic variant NM_015560.3: c.1861C>T (p.Gln621Ter) in heterozygosis in OPA1. To this end, a protocol based on supplementing the iPSC culture media with several small molecules and defined factors trying to mimic embryonic development has been employed. Subsequently, the created model was validated, confirming the presence of a defect of intergenomic communication, impaired mitochondrial respiration, and an increase in apoptosis and ROS generation. Finally, we propose the analysis of OPA1 expression by qPCR as an easy read-out method to carry out future drug screening studies using the created RGC model. In summary, this model provides a useful platform for further investigation of the underlying pathophysiological mechanisms of ADOA plus and for testing compounds with potential pharmacological action.

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.

Modeling HIV-1 infection and NeuroHIV in hiPSCs-derived cerebral organoid cultures

The human immunodeficiency virus (HIV) epidemic is an ongoing global health problem affecting 38 million people worldwide with nearly 1.6 million new infections every year. Despite the advent of combined antiretroviral therapy (cART), a large percentage of people with HIV (PWH) still develop neurological deficits, grouped into the term of HIV-associated neurocognitive disorders (HAND). Investigating the neuropathology of HIV is important for understanding mechanisms associated with cognitive impairment seen in PWH. The major obstacle for studying neuroHIV is the lack of suitable in vitro human culture models that could shed light into the HIV-CNS interactions. Recent advances in induced pluripotent stem cell (iPSC) culture and 3D brain organoid systems have allowed the generation of 2D and 3D culture methods that possess a potential to serve as a model of neurotropic viral diseases, including HIV. In this study, we first generated and characterized several hiPSC lines from healthy human donor skin fibroblast cells. hiPSCs were then used for the generation of microglia-containing human cerebral organoids (hCOs). Once fully characterized, hCOs were infected with HIV-1 in the presence and absence of cART regimens and viral infection was studied by cellular, molecular/biochemical, and virological assays. Our results revealed that hCOs were productively infected with HIV-1 as evident by viral p24-ELISA in culture media, RT-qPCR and RNAscope analysis of viral RNA, as well as ddPCR analysis of proviral HIV-1 in genomic DNA samples. More interestingly, replication and gene expression of HIV-1 were also greatly suppressed by cART in hCOs as early as 7 days post-infections. Our results suggest that hCOs derived from hiPSCs support HIV-1 replication and gene expression and may serve as a unique platform to better understand neuropathology of HIV infection in the brain.

ECCO Grant Ablating perianal fistulizing Crohn’s disease through genetically engineered patient specific induced pluripotent stem cells (iPSC)-derived stromal cells

Abstract Background and Aims Despite the wide range of available therapies treatment of perianal fistulizing Crohn’s disease (pCD) remains challenging. Therefore, exploring new effective therapies is of crucial importance. Local injection of allogeneic mesenchymal stromal cells has been reported to be effective, however, application of these cells is hindered by their limited expandability and differences in therapeutic effect due to donor variations. To overcome these problems, induced pluripotent stem cells (iPSC) can be used to create stromal cells as iPSC can be propagated indefinitely in their undifferentiated state. Therefore, the aim of our study is to generate patient specific iPSC-derived stromal cells of patients with pCD. Furthermore, we will engineer programmed death-ligand 1 (PD-L1)-expressing cultures to enhance the immunomodulatory capacity of these stromal cells. Last, preclinical testing of these cells will be performed in experimental colitis models. Methods Ten patients with pCD will be included at the outpatient clinic in the Erasmus Medical Center (EMC). Patient specific iPSC will be generated from peripheral blood in the iPSC core facility of the EMC. iPSC cultures will be exposed to a low dose of retinoic acid creating stromal cells. The variety of stromal cells will be sorted using a FACS and a stromal specific sorting panel. In parallel, cultures will be engineered, using CRISPR-Cas technology, to express PD-L1. Mixed lymphocyte reactions will be performed to assess the ability of both transduced and non-transduced cultures to provoke the proliferation of non-MHC matched T-lymphocytes. Next, cultures will be generated to express murine PD-L1 to assess their immunomodulatory capacity in established experimental colitis models to provide essential knowledge for a future clinical trial. Anticipated Impact With this study, we are taking the first steps towards improved remission rates of perianal fistulas in the future. On the long-term, this will result in reduction of health care costs.

Reduced myeloid commitment and increased uptake by macrophages of stem cell-derived HPS2 neutrophils.

Hermansky-Pudlak syndrome type 2 (HPS2) is a rare autosomal recessive disorder, caused by mutations in the AP3B1 gene, encoding the β3A subunit of the adapter protein complex 3. This results in mis-sorting of proteins within the cell. A clinical feature of HPS2 is severe neutropenia. Current HPS2 animal models do not recapitulate the human disease. Hence, we used induced pluripotent stem cells (iPSCs) of an HPS2 patient to study granulopoiesis. Development into CD15POS cells was reduced, but HPS2-derived CD15POS cells differentiated into segmented CD11b+CD16hi neutrophils. These HPS2 neutrophils phenocopied their circulating counterparts showing increased CD63 expression, impaired degranulation capacity, and intact NADPH oxidase activity. Most noticeable was the decrease in neutrophil yield during the final days of HPS2 iPSC cultures. Although neutrophil viability was normal, CD15NEG macrophages were readily phagocytosing neutrophils, contributing to the limited neutrophil output in HPS2. In this iPSC model, HPS2 neutrophil development is affected by a slower rate of development and by macrophage-mediated clearance during neutrophil maturation.

Optimized and Scalable Precoating-Free Reprogramming of Human Peripheral Blood Mononuclear Cells into iPSCs.

Human disease modeling has been profoundly transformed by the introduction of human induced pluripotent stem cells (iPSCs), marking the onset of a new era. This ground-breaking development offers a tailored framework for generating pluripotent cells from any individual, effectively enabling the development of cellular models for the study of human physiology and diseases on an unprecedented scale. Although technologies for iPSCs generation have advanced rapidly over the past two decades, protocols for reprogramming patient-derived somatic cells into stem cells still pose a major challenge for the development of automated pipelines capable of generating iPSCs at scales that are cost-effective, reproducible, and easy to implement. Most methods commonly rely on extracellular matrix protein mixtures or synthetic substrates to promote efficient proliferation of iPSCs. Nonetheless, employing these substances entails a laborious and time-consuming process, as the culture surface requires coating treatments before cell seeding. Here we describe a method for reprogramming blood-derived mononucleated cells that eliminates the need to precoat culture surfaces for the entire experimental flow. This procedure is suitable for fresh or frozen purified peripheral blood mononuclear cells (PBMCs) and allows seeding of reprogrammed cells in a culture medium containing a fragment of laminin-511, regardless of the method of reprogramming employed. Our protocol incorporates a streamlined workflow that optimizes key factors, including cell density, culture medium composition, and iPSC culture propagation techniques. Using a precoating-free approach, we eliminate the time-consuming steps, while our optimized subcloning method improves the scalability of the protocol, making it suitable for large-scale applications. Additionally, the automation-friendly nature of our protocol allows for high-throughput processing, reducing the labor and costs associated with manual handling. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Miniaturized and time efficient precoating-free reprogramming of fresh or frozen PBMCs Alternate Protocol: Erythroid progenitor cells (EPCs) enrichment and reprogramming into iPSCs using Sendai viral vectors Basic Protocol 2: Picking and precoating-free optimized expansion of iPSC clones.

Distribution of APP in endo‐lysosomal system induced by Aβ is modulated by Gβγ signaling

AbstractBackgroundAlzheimer´s disease is characterized by the deposition of aggregated species of amyloid beta (Aβ) in the brain, which leads to progressive cognitive deficits and dementia. We recently found that Aβ assemblies, oligomers and fibrils, increase APP and BACE1 interaction in recycling endosomes and accumulation of intracellular Aβ42 in human neurons derived from iPSCs by a mechanism dependent of APP/Go/Gβγ signaling (Antonino et al 2022, https://doi.org/10.3389/fcell.2022.852738). Now, we are interested on deepen in the APP trafficking in the endo‐lysosomal pathway in order to understand the mechanism underlying such effect.MethodN2a and human neurons derived from iPSc cultures were transfected with fluorescently tagged proteins (APP‐YFP, BACE‐CH, Rab11‐RFP, LAMP1‐CH, Rab7‐CH, APP‐VN, BACE‐VC). Cultures were treated with vehicle or the Gβγ inhibitor gallein and 30 minutes later with vehicle or 1 µM of Aβ oligomeric or fibrillar. After 24 h of treatment quantitative colocalization analysis and bimolecular fluorescence complementation assays were performed.ResultWe found that Aβ induced an enrichment of APP in recycling endosomes at the expense of a decrement of its levels in lysosomes. This change in APP intracellular distribution is drive by Gβγ signaling. Moreover, we found that the changes on APP distribution correlate with an increase in its interaction with BACE1 and with an increase in the number of recycling endosomes, both events modulated by Gβγ signaling (Figure 1,2).ConclusionTogether, these results suggest that Aβ pathological assemblies induce a re‐direction of APP from its physiological route to lysosomes, to recycling endosomes which favors its encounter with BACE1 and its amyloidogenic processing. These finding elucidate the intracellular process which sustain the feed‐forward mechanisms implicated in the amyloidogenesis induced by pathological assemblies of Aβ.

Metabolic regulatory network kinetic modeling with multiple isotopic tracers for iPSCs.

The rapidly expanding market for regenerative medicines and cell therapies highlights the need to advance the understanding of cellular metabolisms and improve the prediction of cultivation production process for human induced pluripotent stem cells (iPSCs). In this paper, a metabolic kinetic model was developed to characterize the underlying mechanisms of iPSC culture process, which can predict cell response to environmental perturbation and support process control. This model focuses on the central carbon metabolic network, including glycolysis, pentose phosphate pathway, tricarboxylic acid cycle, and amino acid metabolism, which plays a crucial role to support iPSC proliferation. Heterogeneous measures of extracellular metabolites and multiple isotopic tracers collected under multiple conditions were used to learn metabolic regulatory mechanisms. Systematic cross-validation confirmed the model's performance in terms of providing reliable predictions on cellular metabolism and culture process dynamics under various culture conditions. Thus, the developed mechanistic kinetic model can support process control strategies to strategically select optimal cell culture conditions at different times, ensure cell product functionality, and facilitate large-scale manufacturing of regenerative medicines and cell therapies.

BCL11B Modulates Hemogenic Endothelium-Derived Multipotent Hematopoietic Progenitors and Enhances Myeloid and Lymphoid Pathways from Human iPSCs

Induced pluripotent stem cell (iPSC) derived human hematopoietic stem cells (HSCs) have revolutionized the field of regenerative medicine and provided a promising platform for advancing cell-based therapies, disease modeling, and drug discovery in the context of hematological disorders and beyond. However, efficient derivation of functional iPSC-derived HSCs with in vivo engraftment and multilineage potential remains challenging. The discovery of the hemogenic endothelium (HE) stage in iPSC culture opens possibilities to define molecular determinants for blood development from the endothelium and provides a prospective platform for the de novo generation of HSCs. BCL11B encodes a transcription factor required for T-cell commitment and is known to play important role in immune and aortic cell function. Recently, BCL11B expressionwas observed in lymphoid-myeloid clusters and HE from human iPSCs (hPSCs). However, nothing is known regarding the role of BCL11B in human hematopoiesis. While expression levels of BCL11B have been tracked in human NK cells, direct evidence showing that BCL11B actively drives NK cell maturation is lacking. Here, we genetically engineered hiPSCs with inducible overexpression of BCL11B via CRISPR/Cas9-mediated gene knock-in and investigated the temporal role of this transcription factor during hematopoietic differentiation. We demonstrated that BCL11B upregulation during the mesodermal stage of development enhances arterial specification from hiPSCs differentiated in chemically defined conditions. The boost in arterial programming by BCL11B was associated with enhanced HE formation and a DLL4 +CXCR4 + arterial phenotype (KDR +CD144 +DLL4 +CXCR +CD73 -CD43 -). We also demonstrated that enhancing definitive hematopoiesis with lympho-myeloid potential could be achieved through modulation of BCL11B expression. Transient BCL11B overexpression enhanced the production of multipotent hematopoietic progenitors (CD34 +CD43 +CD45 +CD235a -CD41a -) and multipotent colony-forming cells (CFCs) in iPSC differentiation culture. Flow cytometry analysis of day 10 cultures showed that early BCL11B expression yielded a 3-fold increase in the arterial hemogenic endothelial (AHE) and a 2.5-fold increase in the putative HSC population. In combination with conventional HSC markers (CD34 +CD38 -CD45RA -CD43 +CD90 +), we also observed the upregulation of the HSC-specific marker CD49f (ITGA6) from dox-treated iBCL11B-iPSCs. CD49f + cells are highly efficient in generating long-term multilineage grafts compared to CD49f - cells. Additionally, our results demonstrated that BCL11B overexpression significantly promoted NK cell generation under chemically defined culture conditions. The resulting iBCL11B-hiPSC-derived NK cells exhibited various mature NK-specific markers and displayed effective cellular cytotoxicity, with more rapid killing kinetics compared to NK cells derived from no-dox-treated iBCL11B-iPSCs. We conclude that BCL11B-enforced activation during early mesoderm induction yields an increased population of hematopoietic progenitors with lymphoid and myeloid lineage potential, serving as an improved off-the-shelf cell source for targeted cancer immunotherapy.

CRISPR/Cas9 Directed Reprogramming of iPSC for Accelerated Motor Neuron Differentiation Leads to Dysregulation of Neuronal Fate Patterning and Function.

Neurodegeneration causes a significant disease burden and there are few therapeutic interventions available for reversing or slowing the disease progression. Induced pluripotent stem cells (iPSCs) hold significant potential since they are sourced from adult tissue and have the capacity to be differentiated into numerous cell lineages, including motor neurons. This differentiation process traditionally relies on cell lineage patterning factors to be supplied in the differentiation media. Genetic engineering of iPSC with the introduction of recombinant master regulators of motor neuron (MN) differentiation has the potential to shorten and streamline cell developmental programs. We have established stable iPSC cell lines with transient induction of exogenous LHX3 and ISL1 from the Tet-activator regulatory region and have demonstrated that induction of the transgenes is not sufficient for the development of mature MNs in the absence of neuron patterning factors. Comparative global transcriptome analysis of MN development from native and Lhx-ISL1 modified iPSC cultures demonstrated that the genetic manipulation helped to streamline the neuronal patterning process. However, leaky gene expression of the exogenous MN master regulators in iPSC resulted in the premature activation of genetic pathways characteristic of the mature MN function. Dysregulation of metabolic and regulatory pathways within the developmental process affected the MN electrophysiological responses.

Mitochondrial Dysfunction in Dopaminergic Neurons Derived from Patients with LRRK2- and SNCA-Associated Genetic Forms of Parkinson's Disease.

Parkinson's disease (PD) is the second most common neurodegenerative disease. Some cases of PD may be caused by genetic factors, among which mutations in the LRRK2 and SNCA genes play an important role. To develop effective neuroprotective strategies for PD, it is important to diagnose the disease at the earliest stages of the neurodegenerative process. Therefore, the detection of diagnostic and prognostic markers of Parkinson's disease (PD) is an urgent medical need. Advances in induced pluripotent stem cell (iPSC) culture technology provide new opportunities for the search for new biomarkers of PD and its modeling in vitro. In our work, we used a new technology for multiplex profiling of gene expression using barcoding on the Nanostring platform to assess the activity of mitochondrial genes on iPSC-derived cultures of dopaminergic neurons obtained from patients with LRRK2- and SNCA-associated genetic forms PD and a healthy donor. Electron microscopy revealed ultrastructural changes in mitochondria in both LRRK2 and SNCA mutant cells, whereas mitochondria in cells from a healthy donor were normal. In a culture with the SNCA gene mutation, the ratio of the area occupied by mitochondria to the total area of the cytoplasm was significantly lower than in the control and in the line with the LRRK2 gene mutation. Transcriptome analysis of 105 mitochondria proteome genes using the Nanostring platform revealed differences between the diseased and normal cells in the activity of genes involved in respiratory complex function, the tricarboxylic acid cycle, ATP production, mitochondria-endoplasmic reticulum interaction, mitophagy, regulation of calcium concentration, and mitochondrial DNA replication.

A Protocol for Culture and Characterization of Human Induced Pluripotent Stem Cells After Induction.

Human induced pluripotent stem cells (hiPSCs) are characterized by unlimited self-renewal and the capability to differentiate into all three germ layers, with the potential to further differentiate into all types of cells and tissues. Human iPSCs retain all genetic information from their original donors and can be developed into disease models to study disease pathophysiology, identify disease phenotypes and biomarkers, and evaluate therapeutic efficacy and toxicity for drug development. Human iPSCs can also be used to develop cell therapies and regenerative medicine. In the last decade, the technologies for hiPSC generation and differentiation have advanced rapidly. Human iPSC culture and propagation are tedious and require careful handling. High-quality hiPSCs are necessary for downstream applications. The methods, techniques, and skills for hiPSC maintenance and characterization are very different from those for immortalized cell lines. It can be a challenge for new laboratory staff, and sometimes even for experienced staff, to properly culture and maintain the high quality of these cells. Here, we describe a comprehensive set of protocols for hiPSC propagation under chemically defined and feeder-free culture conditions. These step-by-step protocols describe in detail all the reagents and experimental procedures needed to culture hiPSCs. The protocols also describe experimental methods for hiPSC characterization, including immunofluorescence staining and flow cytometric analysis with a panel of pluripotency markers, a teratoma formation assay for validation of in vivo pluripotency, and detection of Sendai virus to ensure elimination of the viral vectors. These protocols have been successfully used in our laboratory for hiPSC expansion and propagation, and this article provide a useful reference guide for laboratory staff to work on hiPSC culture. Published 2023. This article is a U.S. Government work and is in the public domain in the USA. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Propagation and cryopreservation of hiPSC cultures Basic Protocol 2: Recovery of cryopreserved hiPSCs Basic Protocol 3: Validation of pluripotency markers via immunocytochemical analysis Alternate Protocol: Determination of the expression of pluripotency markers via flow cytometry analysis Basic Protocol 4: Assessment of pluripotency via in vivo teratoma formation assay Basic Protocol 5: Confirmation of Sendai viral vector clearance via RT-PCR.

Differentiation and Subculturing of Renal Proximal Tubular-like Cells Derived from Human iPSC.

Recently, we have developed a protocol to differentiate human induced pluripotent stem cells (iPSC) into proximal tubular-like cells (PTL) (Chandrasekaran etal., 2021). These cells express proximal tubular-specific markers, including megalin, and form a polarized monolayer expressing tight junction proteins, including ZO-3 and occludin. Furthermore, PTL display functional properties, including megalin-facilitated endocytosis, P-glycoprotein (ABCB1) efflux, and respond to parathyroid hormone. Here, we report step-by-step protocols to culture iPSC prior to differentiation (Basic Protocol 1), to differentiate PTL from iPSC (Basic Protocol 2), and to passage and freeze-thaw PTL (Basic Protocol 3). Additionally, we provide a protocol (Basic Protocol 4) to culture PTL on microporous growth supports (transwells). Immunofluorescence stainings for characteristic markers, including megalin, are shown for unpassaged (Basic Protocol 2) and passaged (Basic Protocol 3) PTL. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: iPSC culture Basic Protocol 2: iPSC-derived PTL differentiation Basic Protocol 3: PTL passaging, culturing, and freezing Basic Protocol 4: PTL culturing on transwells Support Protocol 1: Preparation of Geltrex-coated cell culture plates Support Protocol 2: Preparation of RPTEC/TERT1 or fHDF/TERT166-ECM-coated cell culture plates Support Protocol 3: Preparation of human collagen IV-coated cell culture plates Support Protocol 4: Immunofluorescence staining.

An Ethanol Extract of Coptidis rhizoma Induces Apoptotic Cell Death in Induced Pluripotent Stem Cells and Suppresses Teratoma Formation.

In cell-based regenerative medicine, induced pluripotent stem cells (iPSCs) generated from reprogrammed adult somatic cells have emerged as a useful cell source due to the lack of ethical concerns and the low risk of immune rejection. To address the risk of teratoma formation, which is a safety issue in iPSC-based cell therapy, it is essential to selectively remove undifferentiated iPSCs remaining in the iPSC-derived differentiated cell product prior to in vivo transplantation. In this study, we explored whether an ethanol extract of coptidis rhizoma (ECR) exhibited anti-teratoma activity and identified the active components involved in the selective elimination of undifferentiated iPSCs. Transcriptome analysis of iPSCs confirmed that cell death-related pathways were significantly altered by ECR treatment. Our results demonstrate that ECR effectively induced apoptotic cell death and DNA damage in iPSCs, and that reactive oxygen species generation, mitochondrial damage, caspase activation, and p53 activation were involved in ECR-mediated iPSC death. However, in iPSC-derived differentiated cells (iPSC-Diff), reduced cell viability and the DNA damage response were not observed after ECR treatment. We co-cultured iPSCs and iPSC-Diff and found that ECR treatment selectively removed iPSCs, whereas iPSC-Diff remained intact. Prior to in ovo implantation, ECR treatment of a mixed cell culture of iPSCs and iPSC-Diff significantly suppressed iPSC-derived teratoma formation. Among the main components of the ECR, berberine and coptisine showed selective cytotoxicity to iPSCs but not to iPSC-Diff. Together, these results indicate the usefulness of ECRs in preparing safe and effective iPSC-based therapeutic cell products with no risk of teratoma formation.

Efficient generation of marmoset primordial germ cell-like cells using induced pluripotent stem cells.

Reconstitution of germ cell fate from pluripotent stem cells provides an opportunity to understand the molecular underpinnings of germ cell development. Here, we established robust methods for induced pluripotent stem cell (iPSC) culture in the common marmoset (Callithrix jacchus [cj]), allowing stable propagation in an undifferentiated state. Notably, iPSCs cultured on a feeder layer in the presence of a WNT signaling inhibitor upregulated genes related to ubiquitin-dependent protein catabolic processes and enter a permissive state that enables differentiation into primordial germ cell-like cells (PGCLCs) bearing immunophenotypic and transcriptomic similarities to pre-migratory cjPGCs in vivo. Induction of cjPGCLCs is accompanied by transient upregulation of mesodermal genes, culminating in the establishment of a primate-specific germline transcriptional network. Moreover, cjPGCLCs can be expanded in monolayer while retaining the germline state. Upon co-culture with mouse testicular somatic cells, these cells acquire an early prospermatogonia-like phenotype. Our findings provide a framework for understanding and reconstituting marmoset germ cell development in vitro, thus providing a comparative tool and foundation for a preclinical modeling of human in vitro gametogenesis.

Maintenance of methylation profile in imprinting control regions in human induced pluripotent stem cells

BackgroundParental imprinting is an epigenetic mechanism that leads to monoallelic expression of a subset of genes depending on their parental origin. Imprinting disorders (IDs), caused by disturbances of imprinted genes, are a set of rare congenital diseases that mainly affect growth, metabolism and development. To date, there is no accurate model to study the physiopathology of IDs or test therapeutic strategies. Human induced pluripotent stem cells (iPSCs) are a promising cellular approach to model human diseases and complex genetic disorders. However, aberrant hypermethylation of imprinting control regions (ICRs) may appear during the reprogramming process and subsequent culture of iPSCs. Therefore, we tested various conditions of reprogramming and culture of iPSCs and performed an extensive analysis of methylation marks at the ICRs to develop a cellular model that can be used to study IDs.ResultsWe assessed the methylation levels at seven imprinted loci in iPSCs before differentiation, at various passages of cell culture, and during chondrogenic differentiation. Abnormal methylation levels were found, with hypermethylation at 11p15 H19/IGF2:IG-DMR and 14q32 MEG3/DLK1:IG-DMR, independently of the reprogramming method and cells of origin. Hypermethylation at these two loci led to the loss of parental imprinting (LOI), with biallelic expression of the imprinted genes IGF2 and DLK1, respectively. The epiPS™ culture medium combined with culturing of the cells under hypoxic conditions prevented hypermethylation at H19/IGF2:IG-DMR (ICR1) and MEG3/DLK1:IG-DMR, as well as at other imprinted loci, while preserving the proliferation and pluripotency qualities of these iPSCs.ConclusionsAn extensive and quantitative analysis of methylation levels of ICRs in iPSCs showed hypermethylation of certain ICRs in human iPSCs, especially paternally methylated ICRs, and subsequent LOI of certain imprinted genes. The epiPS™ culture medium and culturing of the cells under hypoxic conditions prevented hypermethylation of ICRs in iPSCs. We demonstrated that the reprogramming and culture in epiPS™ medium allow the generation of control iPSCs lines with a balanced methylation and ID patient iPSCs lines with unbalanced methylation. Human iPSCs are therefore a promising cellular model to study the physiopathology of IDs and test therapies in tissues of interest.

Leveraging the power of AI to design the best performing iPSC culture media

You will learn how to automatically create custom and optimized media formulations based on peer-reviewed research for induced pluripotent stem cell (iPSC)-based therapyIndependent of the cell type used in your process, learn how you can improve key critical quality attributes related to your therapy by having a customized media formulationLearn how to maintain IP ownership of the formulations you create and easily order them in the preferred format, size, and packaging to reduce cost and mitigate supply chain risksInstantly canvas publicly accessible scientific content and extract component and concentration level information to dramatically reduce the time to research and design custom formulationsDr Asma Ayari is Nucleus Biologics' Head of R&D, running Formulation Services & Product Development and has extensive experience in media analysis, testing and formulation for Cell and Gene Therapy. Asma did her PhD work in virology and immunology and brings a deep understanding of how complex cellular systems are affected by small changes in the chemical composition of the microenvironment. Dr Ayari holds a MSc. in Microbiology from University of Tunis and a PhD in Virology, Immunology and Metabolism from University of Lille in France.

Investigation of PTC124-mediated translational readthrough in a retinal organoid model of AIPL1-associated Leber congenital amaurosis.

SummaryLeber congenital amaurosis type 4 (LCA4), caused by AIPL1 mutations, is characterized by severe sight impairment in infancy and rapidly progressing degeneration of photoreceptor cells. We generated retinal organoids using induced pluripotent stem cells (iPSCs) from renal epithelial cells obtained from four children with AIPL1 nonsense mutations. iPSC-derived photoreceptors exhibited the molecular hallmarks of LCA4, including undetectable AIPL1 and rod cyclic guanosine monophosphate (cGMP) phosphodiesterase (PDE6) compared with control or CRISPR-corrected organoids. Increased levels of cGMP were detected. The translational readthrough-inducing drug (TRID) PTC124 was investigated as a potential therapeutic agent. LCA4 retinal organoids exhibited low levels of rescue of full-length AIPL1. However, this was insufficient to fully restore PDE6 in photoreceptors and reduce cGMP. LCA4 retinal organoids are a valuable platform for in vitro investigation of novel therapeutic agents.

Investigating Peripheral Regional Anesthesia Using Induced Pluripotent Stem Cell Technology: Exploring Novel Terrain.

Investigating Peripheral Regional Anesthesia Using Induced Pluripotent Stem Cell Technology: Exploring Novel Terrain.

Xeno-Free Materials for Stabilizing Basic Fibroblast Growth Factor and Enhancing Cell Proliferation in Human Pluripotent Stem Cell Cultures.

Induced pluripotent stem cells (iPSCs) are widely considered important for developing novel regenerative therapies. A major challenge to the growth and proliferation of iPSCs is the maintenance of their undifferentiated status in xeno- and feeder-free conditions. Basic fibroblast growth factor (bFGF) is known to contribute to the expansion of stem cells; however, bFGF is notoriously heat-labile and easily denatured. Here, we investigate the effects of a series of synthetic sulfated/sulfonated polymers and saccharides on the growth of iPSCs. We observed that these materials effectively prevented the reduction of bFGF levels in iPSC culture media during storage at 37 °C. Some of the tested materials also suppressed heat-induced decline in medium performance and maintained cell proliferation. Our results suggest that these sulfated materials can be used to improve the expansion culture of undifferentiated iPSCs and show the potential of cost effective, chemically defined materials for improvement of medium performance while culturing iPSCs.