Human-Induced Pluripotent Stem Cells Manufactured Using a Current Good Manufacturing Practice-Compliant Process Differentiate Into Clinically Relevant Cells From Three Germ Layers

OCT4 protein and gene expression analysis in the differentiation of spermatogonia stem cells into neurons by immunohistochemistry, immunocytochemistry, and bioinformatics analysis

BACKGROUND

Spermatogonia Stem Cells (SSCs) are potential candidates for reprogramming and regeneration. Recent studies have revealed that differentiated cells can be reverted to pluripotent by overexpressing a set of pluripotent transcription factors. OCT4 (encoded by pou5f1), a POU transcription factor family member, is essential to the potential that controls pluripotency, and it is widely expressed in pluripotent stem cells, although it decreased or suppressed after differentiation.

METHODS

In this investigated research, we examined the OCT4 expression during the differentiation of SSCs into neurons (involving four stages in the following order: SSCs in vivo and in-vitro, embryonic Stem Cell-like (ES-like), Embryonic Bodies (EBs), and finally Neurons) by Immunocytochemistry (ICC), Immunohistochemistry (IMH), and Fluidigm Real-Time polymerase chain reaction. In addition, we use some databases like STRING to predict protein-protein interaction and enrichment analysis.

RESULTS

We evaluated the expression of OCT4 in this process, and we observed that it is expressed in SSCs, ES-like, and EBs during the differentiation of spermatogonia stem cells into adult neurons. We show that by adding RA to EBs, the expression of OCT4 is reduced and is not expressed in the neuron cells. We observed that the expression of OCT4 is linked and interacts with the differentiation of spermatogonia stem cells into neuron cells, and it has been shown to be biologically functional, like stem cell maintenance and somatic cell reprogramming.

CONCLUSION

Our findings can help us better understand the process of differentiation of spermatogonia stem cells into neurons, and it can be effective in finding new and more efficient treatments for neurogenesis and repair of neurons. We examined the OCT4 expression during the differentiation of SSCs into neurons (involving four stages in the following order: SSCs in vivo and in-vitro, embryonic Stem Cell-like (ES-like), Embryonic Bodies (EBs), and finally Neurons) by Immunocytochemistry (ICC), Immunohistochemistry (IMH), and Fluidigm Real-Time polymerase chain reaction. In addition, we use some databases like STRING to predict protein-protein interaction and enrichment analysis. We evaluated the expression of OCT4 in this process, and we observed that it is expressed in SSCs, ES-like, and EBs during the differentiation of spermatogonia stem cells into adult neurons. We show that by adding RA to EBs, the expression of OCT4 is reduced and is not expressed in the neuron cells. We observed that the expression of OCT4 is linked and interacts with the differentiation of spermatogonia stem cells into neuron cells, and it has been shown to be biologically functional, like stem cell maintenance and somatic cell reprogramming.

An Efficient 2D Protocol for Differentiation of iPSCs into Mature Postmitotic Dopaminergic Neurons: Application for Modeling Parkinson's Disease

About 15% of patients with parkinsonism have a hereditary form of Parkinson's disease (PD). Studies on the early stages of PD pathogenesis are challenging due to the lack of relevant models. The most promising ones are models based on dopaminergic neurons (DAns) differentiated from induced pluripotent stem cells (iPSCs) of patients with hereditary forms of PD. This work describes a highly efficient 2D protocol for obtaining DAns from iPSCs. The protocol is rather simple, comparable in efficiency with previously published protocols, and does not require viral vectors. The resulting neurons have a similar transcriptome profile to previously published data for neurons, and have a high level of maturity marker expression. The proportion of sensitive (SOX6+) DAns in the population calculated from the level of gene expression is higher than resistant (CALB+) DAns. Electrophysiological studies of the DAns confirmed their voltage sensitivity and showed that a mutation in the PARK8 gene is associated with enhanced store-operated calcium entry. The study of high-purity DAns differentiated from the iPSCs of patients with hereditary PD using this differentiation protocol will allow for investigators to combine various research methods, from patch clamp to omics technologies, and maximize information about cell function in normal and pathological conditions.

Characterization of human induced pluripotent stems cells: Current approaches, challenges, and future solutions

Human induced pluripotent stem cells (iPSC) have demonstrated massive potentials for use in regenerative and personalized medicine due to their ability to expand in culture and differentiate into specialized cells with therapeutic benefits. However, in order to industrialize iPSC-derived therapies, it is necessary to address the existing challenges surrounding the analytics implemented in the manufacturing process to evaluate and monitor cell expansion, differentiation, and quality of the final products. Here, we review some of the key analytical methods used as part of identity, potency, or safety for in-process or final product release testing and highlighted the challenges and potential solutions for consideration in the Chemistry, Manufacturing and Controls (CMC) strategy for iPSC-based therapies. Some of the challenges associated with characterization and testing of iPSC-based products are related to the choice of analytical technology (to ensure fit-for-purpose), assay reliability and robustness. Automation of analytical methods may be required to reduce hands on time, and improve reliability of the methods through reducing assay variability. Indeed, we have shown that automation of analytical methods is feasible (evaluated using an ELISA based assay) and would result in more precise measurements (demonstrated by lower co-efficient of Variation and standard deviation), less hands-on time, and swift compared to a manually run assay. Therefore, in order to support commercialization of iPSC-based therapies we suggest a well-designed testing strategy to be established in the development phase while incorporating robust, reproducible, reliable, and potentially automated analytics in the manufacturing process.

Modeling Movement Disorders via Generation of hiPSC-Derived Motor Neurons

Generation of motor neurons (MNs) from human-induced pluripotent stem cells (hiPSCs) overcomes the limited access to human brain tissues and provides an unprecedent approach for modeling MN-related diseases. In this review, we discuss the recent progression in understanding the regulatory mechanisms of MN differentiation and their applications in the generation of MNs from hiPSCs, with a particular focus on two approaches: induction by small molecules and induction by lentiviral delivery of transcription factors. At each induction stage, different culture media and supplements, typical growth conditions and cellular morphology, and specific markers for validation of cell identity and quality control are specifically discussed. Both approaches can generate functional MNs. Currently, the major challenges in modeling neurological diseases using iPSC-derived neurons are: obtaining neurons with high purity and yield; long-term neuron culture to reach full maturation; and how to culture neurons more physiologically to maximize relevance to in vivo conditions.

Generating iPSCs with a High-Efficient, Non-Invasive Method-An Improved Way to Cultivate Keratinocytes from Plucked Hair for Reprogramming

Various somatic cell types are suitable for induced pluripotency reprogramming, such as dermal fibroblasts, mesenchymal stem cells or hair keratinocytes. Harvesting primary epithelial keratinocytes from plucked human hair follicles (HFs) represents an easy and non-invasive alternative to a fibroblast culture from invasive skin biopsies. Nevertheless, to facilitate and simplify the process, which can be divided into three main steps (collecting, culturing and reprogramming), the whole procedure of generating hair keratinocytes has to be revised and upgraded continuously. In this study, we address advancements and approaches which improve the generation and handling of primary HF-derived keratinocytes tremendously, e.g., for iPSCs reprogramming. We not only evaluated different serum- and animal-origin-free media, but also supplements and coating solutions for an enhanced protocol. Here, we demonstrate the importance of speed and accuracy in the collecting step, as well as the choice of the right transportation medium. Our results lead to a more defined approach that further increases the reliability of downstream experiments and inter-laboratory reproducibility. These improvements will make it possible to obtain keratinocytes from plucked human hair for the generation of donor-specific iPSCs easier and more efficient than ever before, whilst preserving a non-invasive capability.

Pharmacological Manipulation of Wnt/β-Catenin Signaling Pathway in Human Neural Precursor Cells Alters Their Differentiation Potential and Neuronal Yield

The canonical Wnt/β-catenin pathway is a master-regulator of cell fate during embryonic and adult neurogenesis and is therefore a major pharmacological target in basic and clinical research. Chemical manipulation of Wnt signaling during in vitro neuronal differentiation of stem cells can alter both the quantity and the quality of the derived neurons. Accordingly, the use of Wnt activators and blockers has become an integral part of differentiation protocols applied to stem cells in recent years. Here, we investigated the effects of the glycogen synthase kinase-3β inhibitor CHIR99021, which upregulates β-catenin agonizing Wnt; and the tankyrase-1/2 inhibitor XAV939, which downregulates β-catenin antagonizing Wnt. Both drugs and their potential neurogenic and anti-neurogenic effects were studied using stable lines human neural precursor cells (hNPCs), derived from embryonic stem cells, which can be induced to generate mature neurons by chemically-defined conditions. We found that Wnt-agonism by CHIR99021 promotes induction of neural differentiation, while also reducing cell proliferation and survival. This effect was not synergistic with those of pro-neural growth factors during long-term neuronal differentiation. Conversely, antagonism of Wnt by XAV939 consistently prevented neuronal progression of hNPCs. We show here how these two drugs can be used to manipulate cell fate and how self-renewing hNPCs can be used as reliable human in vitro drug-screening platforms.

Stem Cells as a Source of Pancreatic Cells for Production of 3D Bioprinted Bionic Pancreas in the Treatment of Type 1 Diabetes

Type 1 diabetes (T1D) is the third most common autoimmune disease which develops due to genetic and environmental risk factors. Often, intensive insulin therapy is insufficient, and patients require a pancreas or pancreatic islets transplant. However, both solutions are associated with many possible complications, including graft rejection. The best approach seems to be a donor-independent T1D treatment strategy based on human stem cells cultured in vitro and differentiated into insulin and glucagon-producing cells (β and α cells, respectively). Both types of cells can then be incorporated into the bio-ink used for 3D printing of the bionic pancreas, which can be transplanted into T1D patients to restore glucose homeostasis. The aim of this review is to summarize current knowledge about stem cells sources and their transformation into key pancreatic cells. Last, but not least, we comment on possible solutions of post-transplant immune response triggered stem cell-derived pancreatic cells and their potential control mechanisms.

Expansion of Human Pluripotent Stem Cells in Stirred Tank Bioreactors

Bioreactor technolology enables the expansion of mammalian cells, which can be translated to processes compatible with Current Good Manufacturing Practice (cGMP) regulations. Cells are introduced to the bioreactor vessel, wherein key parameters such as temperature, pH, and oxygen levels are tightly controlled to facilitate growth over time. Here, we describe the microcarrier-based expansion of human pluripotent stem cells in a 3 L stirred tank bioreactor.

Early functional changes associated with alpha-synuclein proteinopathy in engineered human neural networks

A patterned spread of proteinopathy represents a common characteristic of many neurodegenerative diseases. In Parkinson's disease (PD), misfolded forms of α-synuclein proteins accumulate in hallmark pathological inclusions termed Lewy bodies and Lewy neurites. Such protein aggregates seem to affect selectively vulnerable neuronal populations in the substantia nigra and to propagate within interconnected neuronal networks. Research findings suggest that these proteinopathic inclusions are present at very early time points in disease development, even before clear behavioral symptoms of dysfunction arise. In this study, we investigate the early pathophysiology developing after induced formation of such PD-related α-synuclein inclusions in a physiologically relevant in vitro setup using engineered human neural networks. We monitor the neural network activity using multielectrode arrays (MEAs) for a period of 3 wk following proteinopathy induction to identify associated changes in network function, with a special emphasis on the measure of network criticality. Self-organized criticality represents the critical point between resilience against perturbation and adaptational flexibility, which appears to be a functional trait in self-organizing neural networks, both in vitro and in vivo. We show that although developing pathology at early onset is not clearly manifest in standard measurements of network function, it may be discerned by investigating differences in network criticality states.

MUSE Stem Cells Can Be Isolated from Stromal Compartment of Mouse Bone Marrow, Adipose Tissue, and Ear Connective Tissue: A Comparative Study of Their In Vitro Properties

The cells present in the stromal compartment of many tissues are a heterogeneous population containing stem cells, progenitor cells, fibroblasts, and other stromal cells. A SSEA3(+) cell subpopulation isolated from human stromal compartments showed stem cell properties. These cells, known as multilineage-differentiating stress-enduring (MUSE) cells, are capable of resisting stress and possess an excellent ability to repair DNA damage. We isolated MUSE cells from different mouse stromal compartments, such as those present in bone marrow, subcutaneous white adipose tissue, and ear connective tissue. These cells showed overlapping in vitro biological properties. The mouse MUSE cells were positive for stemness markers such as SOX2, OCT3/4, and NANOG. They also expressed TERT, the catalytic telomerase subunit. The mouse MUSE cells showed spontaneous commitment to differentiation in meso/ecto/endodermal derivatives. The demonstration that multilineage stem cells can be isolated from an animal model, such as the mouse, could offer a valid alternative to the use of other stem cells for disease studies and envisage of cellular therapies.

Clinical-Grade Human Pluripotent Stem Cells for Cell Therapy: Characterization Strategy

Human pluripotent stem cells have the potential to change the way in which human diseases are cured. Clinical-grade human embryonic stem cells and human induced pluripotent stem cells have to be created according to current good manufacturing practices and regulations. Quality and safety must be of the highest importance when humans' lives are at stake. With the rising number of clinical trials, there is a need for a consensus on hPSCs characterization. Here, we summarize mandatory and 'for information only' characterization methods with release criteria for the establishment of clinical-grade hPSC lines.

Addressing Manufacturing Challenges for Commercialization of iPSC-Based Therapies

The development of reprogramming technology to generate human induced pluripotent stem cells (iPSCs) has tremendously influenced the field of regenerative medicine and clinical therapeutics where curative cell replacement therapies can be used in the treatment of devastating diseases such as Parkinson's disease (PD) and diabetes. In order to commercialize these therapies to treat a large number of individuals, it is important to demonstrate the safety and efficacy of these therapies and ensure that the manufacturing process for iPSC-derived functional cells can be industrialized at an affordable cost. However, there are a number of manufacturing obstacles that need to be addressed in order to meet this vision. It is important to note that the manufacturing process for generation of iPSC-derived specialized cells is relatively long and fairly complex and requires differentiation of high-quality iPSCs into specialized cells in a controlled manner. In this chapter, we have summarized our efforts to address the main challenges present in the industrialization of iPSC-derived cell therapy products with focus on the development of a current Good Manufacturing Practice (cGMP)-compliant iPSC manufacturing process, a comprehensive iPSC characterization platform, long-term stability of cGMP compliant iPSCs, and innovative technologies to address some of the scale-up challenges in establishment of iPSC processing in 3D computer-controlled bioreactors.

Long-Term Stability and Differentiation Potential of Cryopreserved cGMP-Compliant Human Induced Pluripotent Stem Cells

The clinical effectiveness of human induced pluripotent stem cells (iPSCs) is highly dependent on a few key quality characteristics including the generation of high quality cell bank, long-term genomic stability, post-thaw viability, plating efficiency, retention of pluripotency, directed differentiation, purity, potency, and sterility. We have already reported the establishment of iPSC master cell banks (MCBs) and working cell banks (WCBs) under current good manufacturing procedure (cGMP)-compliant conditions. In this study, we assessed the cellular and genomic stability of the iPSC lines generated and cryopreserved five years ago under cGMP-compliant conditions. iPSC lines were thawed, characterized, and directly differentiated into cells from three germ layers including cardiomyocytes (CMs), neural stem cells (NSCs), and definitive endoderm (DE). The cells were also expanded in 2D and 3D spinner flasks to evaluate their long-term expansion potential in matrix-dependent and feeder-free culture environment. All three lines successfully thawed and attached to the L7^TM matrix, and formed typical iPSC colonies that expressed pluripotency markers over 15 passages. iPSCs maintained their differentiation potential as demonstrated with spontaneous and directed differentiation to the three germ layers and corresponding expression of specific markers, respectfully. Furthermore, post-thaw cells showed normal karyotype, negative mycoplasma, and sterility testing. These cells maintained both their 2D and 3D proliferation potential after five years of cryopreservation without acquiring karyotype abnormality, loss of pluripotency, and telomerase activity. These results illustrate the long-term stability of cGMP iPSC lines, which is an important step in establishing a reliable, long-term source of starting materials for clinical and commercial manufacturing of iPSC-derived cell therapy products.

End-to-End Platform for Human Pluripotent Stem Cell Manufacturing

Industrialization of stem-cell based therapies requires innovative solutions to close the gap between research and commercialization. Scalable cell production platforms are needed to reliably deliver the cell quantities needed during the various stages of development and commercial supply. Human pluripotent stem cells (hPSCs) are a key source material for generating therapeutic cell types. We have developed a closed, automated and scalable stirred tank bioreactor platform, capable of sustaining high fold expansion of hPSCs. Such a platform could facilitate the in-process monitoring and integration of online monitoring systems, leading to significantly reduced labor requirements and contamination risk. hPSCs are expanded in a controlled bioreactor using perfused xeno-free media. Cell harvest and concentration are performed in closed steps. The hPSCs can be cryopreserved to generate a bank of cells, or further processed as needed. Cryopreserved cells can be thawed into a two-dimensional (2D) tissue culture platform or a three-dimensional (3D) bioreactor to initiate a new expansion phase, or be differentiated to the clinically relevant cell type. The expanded hPSCs express hPSC-specific markers, have a normal karyotype and the ability to differentiate to the cells of the three germ layers. This end-to-end platform allows a large scale expansion of high quality hPSCs that can support the required cell demand for various clinical indications.

Computational fluid dynamics modeling, a novel, and effective approach for developing scalable cell therapy manufacturing processes

Induced pluripotent stem cells (iPSCs) hold great potential to generate novel, curative cell therapy products. However, current methods to generate these novel therapies lack scalability, are labor-intensive, require a large footprint, and are not suited to meet clinical and commercial demands. Therefore, it is necessary to develop scalable manufacturing processes to accommodate the generation of high-quality iPSC derivatives under controlled conditions. The current scale-up methods used in cell therapy processes are based on empirical, geometry-dependent methods that do not accurately represent the hydrodynamics of 3D bioreactors. These methods require multiple iterations of scale-up studies, resulting in increased development cost and time. Here we show a novel approach using computational fluid dynamics modeling to effectively scale-up cell therapy manufacturing processes in 3D bioreactors. Using a GMP-compatible iPSC line, we translated and scaled-up a small-scale cardiomyocyte differentiation process to a 3-L computer-controlled bioreactor in an efficient manner, showing comparability in both systems.

Stem cells for babies and their surgeons: The future is now

Pediatric surgeons are ideal allies for the translation of basic science including stem cell therapies. In the spirit of Robert E. Gross, of applying creative solutions to pediatric problems with technical expertise, we describe the impending cellular therapies that may be derived from stem and progenitor cells. Understanding the types and capabilities of stem and progenitor cells is important for pediatric surgeons to join and facilitate progress for babies. We are developing an induced pluripotent stem cell therapy for enteric neuropathies such as Hirschsprung disease that might be helpful for children in the near future. Our goals, which we hope to share with other surgeons and scientists, include working to establish safe clinical trials and meeting regulatory standards in a thoughtful way that balances patients need and unknown risks.

Concise Review: Towards the Clinical Translation of Induced Pluripotent Stem Cell-Derived Blood Cells-Ready for Take-Off

Since their discovery in 2006, induced pluripotent stem cells (iPSCs) have opened up a world of possibilities for regenerative medicine and novel cell‐based therapeutics. Now, over a decade later, robust reprogramming and expansion and differentiation protocols have been developed, and iPSC‐derived cells have been used in a wide variety of small and large animal models to treat many different diseases. Furthermore, the first iPSC derivatives are on their way into clinical trials. In this line, (i) GMP‐compliant generation, cultivation, and differentiation, (ii) preclinical efficacy and safety, as well as (iii) ethical and regulatory compliance of stem cell research represent important aspects that need to be evaluated for proper clinical translation of iPSCs and their derivatives. In this review article, we provide an overview of the current advances and challenges of the clinical translation of iPSC‐derived blood cells and highlight the most pressing problems that have to be overcome in the next years. stem cells translational medicine2019;8:332–339