Induced Pluripotent Stem Cells (iPSCs)-Roles in Regenerative Therapies, Disease Modelling and Drug Screening.

The discovery of induced pluripotent stem cells (iPSCs) has made an invaluable contribution to the field of regenerative medicine, paving way for identifying the true potential of human embryonic stem cells (ESCs). Since the controversy around ethicality of ESCs continue to be debated, iPSCs have been used to circumvent the process around destruction of the human embryo. The use of iPSCs have transformed biological research, wherein increasing number of studies are documenting nuclear reprogramming strategies to make them beneficial models for drug screening as well as disease modelling. The flexibility around the use of iPSCs include compatibility to non-invasive harvesting, and ability to source from patients with rare diseases. iPSCs have been widely used in cardiac disease modelling, studying inherited arrhythmias, neural disorders including Alzheimer's disease, liver disease, and spinal cord injury. Extensive research around identifying factors that are involved in maintaining the identity of ESCs during induction of pluripotency in somatic cells is undertaken. The focus of the current review is to detail all the clinical translation research around iPSCs and the strength of its ever-growing potential in the clinical space.

Mini-Review: Induced pluripotent stem cells and the search for new cell-specific ALS therapeutic targets.

Amongst the most important discoveries in ALS pathobiology are the works demonstrating that multiple cell types contribute to disease onset and progression. However, a significant limitation in ALS research is the inability to obtain tissues from ALS patient brain and spinal cord during the course of the disease. In vivo modeling has provided insights into the role of these cell subtypes in disease onset and progression. However, in vivo models also have shortcomings, including the reliance on a limited number of models based upon hereditary forms of the disease. Therefore, using human induced pluripotent stem cells (iPSC) reprogrammed from somatic cells of ALS patients, with both hereditary and sporadic forms of the disease, and differentiated into cell subtypes of both the central nervous system (CNS) and peripheral nervous system (PNS), have become powerful complementary tools for investigating basic mechanisms of disease as well as a platform for drug discovery. Motor neuron and other neuron subtypes, as well as non-neuronal cells have been differentiated from human iPSC and studied for their potential contributions to ALS pathobiology. As iPSC technologies have advanced, 3D modeling with multicellular systems organised in microfluidic chambers or organoids are the next step in validating the pathways and therapeutic targets already identified. Precision medicine approaches with iPSC using either traditional strategies of screening drugs that target a known pathogenic mechanism as well as "blind-to-target" drug screenings that allow for patient stratification based on drug response rather than clinical characteristics are now being employed.

Use of Human Induced Pluripotent Stem Cells and Kidney Organoids To Develop a Cysteamine/mTOR Inhibition Combination Therapy for Cystinosis.

BACKGROUND: Mutations in CTNS-a gene encoding the cystine transporter cystinosin-cause the rare, autosomal, recessive, lysosomal-storage disease cystinosis. Research has also implicated cystinosin in modulating the mTORC1 pathway, which serves as a core regulator of cellular metabolism, proliferation, survival, and autophagy. In its severest form, cystinosis is characterized by cystine accumulation, renal proximal tubule dysfunction, and kidney failure. Because treatment with the cystine-depleting drug cysteamine only slows disease progression, there is an urgent need for better treatments. METHODS: To address a lack of good human-based cell culture models for studying cystinosis, we generated the first human induced pluripotent stem cell (iPSC) and kidney organoid models of the disorder. We used a variety of techniques to examine hallmarks of cystinosis-including cystine accumulation, lysosome size, the autophagy pathway, and apoptosis-and performed RNA sequencing on isogenic lines to identify differentially expressed genes in the cystinosis models compared with controls. RESULTS: Compared with controls, these cystinosis models exhibit elevated cystine levels, increased apoptosis, and defective basal autophagy. Cysteamine treatment ameliorates this phenotype, except for abnormalities in apoptosis and basal autophagy. We found that treatment with everolimus, an inhibitor of the mTOR pathway, reduces the number of large lysosomes, decreases apoptosis, and activates autophagy, but it does not rescue the defect in cystine loading. However, dual treatment of cystinotic iPSCs or kidney organoids with cysteamine and everolimus corrects all of the observed phenotypic abnormalities. CONCLUSIONS: These observations suggest that combination therapy with a cystine-depleting drug such as cysteamine and an mTOR pathway inhibitor such as everolimus has potential to improve treatment of cystinosis.

Patient and Disease-Specific Induced Pluripotent Stem Cells for Discovery of Personalized Cardiovascular Drugs and Therapeutics.

Human induced pluripotent stem cells (iPSCs) have emerged as an effective platform for regenerative therapy, disease modeling, and drug discovery. iPSCs allow for the production of limitless supply of patient-specific somatic cells that enable advancement in cardiovascular precision medicine. Over the past decade, researchers have developed protocols to differentiate iPSCs to multiple cardiovascular lineages, as well as to enhance the maturity and functionality of these cells. Despite significant advances, drug therapy and discovery for cardiovascular disease have lagged behind other fields such as oncology. We speculate that this paucity of drug discovery is due to a previous lack of efficient, reproducible, and translational model systems. Notably, existing drug discovery and testing platforms rely on animal studies and clinical trials, but investigations in animal models have inherent limitations due to interspecies differences. Moreover, clinical trials are inherently flawed by assuming that all individuals with a disease will respond identically to a therapy, ignoring the genetic and epigenomic variations that define our individuality. With ever-improving differentiation and phenotyping methods, patient-specific iPSC-derived cardiovascular cells allow unprecedented opportunities to discover new drug targets and screen compounds for cardiovascular disease. Imbued with the genetic information of an individual, iPSCs will vastly improve our ability to test drugs efficiently, as well as tailor and titrate drug therapy for each patient.

Phenotypic Drug Screening for Dysferlinopathy Using Patient-Derived Induced Pluripotent Stem Cells.

Dysferlinopathy is a progressive muscle disorder that includes limb-girdle muscular dystrophy type 2B and Miyoshi myopathy (MM). It is caused by mutations in the dysferlin (DYSF) gene, whose function is to reseal the muscular membrane. Treatment with proteasome inhibitor MG-132 has been shown to increase misfolded dysferlin in fibroblasts, allowing them to recover their membrane resealing function. Here, we developed a screening system based on myocytes from MM patient-derived induced pluripotent stem cells. According to the screening, nocodazole was found to effectively increase the level of dysferlin in cells, which, in turn, enhanced membrane resealing following injury by laser irradiation. Moreover, the increase was due to microtubule disorganization and involved autophagy rather than the proteasome degradation pathway. These findings suggest that increasing the amount of misfolded dysferlin using small molecules could represent an effective future clinical treatment for dysferlinopathy. Stem Cells Translational Medicine 2019;8:1017-1029.

Function and Immunogenicity of Gene-corrected iPSC-derived Hepatocyte-Like Cells in Restoring Low Density Lipoprotein Uptake in Homozygous Familial Hypercholesterolemia.

Gene correction of induced pluripotent stem cells (iPSCs) has therapeutic potential for treating homozygous familial hypercholesterolemia (HoFH) associated with low-density lipoprotein (LDL) receptor (LDLR) dysfunction. However, few data exist regarding the functional recovery and immunogenicity of LDLR gene-corrected iPSC-derived hepatocyte-like cells (HLCs) obtained from an HoFH patient. Therefore, we generated iPSC-derived HLCs from an HoFH patient harbouring a point mutation (NM_000527.4:c.901 G > T) in exon 6 of LDLR, and examined their function and immunogenicity. From the patient's iPSCs, one homozygous gene-corrected HoFH-iPSC clone and two heterozygous clones were generated using the CRISPR/Cas9 method. Both types of iPSC-derived HLCs showed recovery of the function of LDL uptake in immunofluorescence staining analysis. Furthermore, these gene-corrected iPSC-derived HLCs showed little immunogenicity against the patient's peripheral blood mononuclear cells in a cell-mediated cytotoxicity assay. These results demonstrate that LDL uptake of iPSC-derived HLCs from HoFH can be restored by gene correction without the appearance of further immunogenicity, suggesting that gene-corrected iPSC-derived HLCs are applicable to the treatment of HoFH.

Evidence for personalised medicine: mechanisms, correlation, and new kinds of black box.

Personalised medicine (PM) has been discussed as a medical paradigm shift that will improve health while reducing inefficiency and waste. At the same time, it raises new practical, regulatory, and ethical challenges. In this paper, we examine PM strategies epistemologically in order to develop capacities to address these challenges, focusing on a recently proposed strategy for developing patient-specific models from induced pluripotent stem cells (iPSCs) so as to make individualised treatment predictions. We compare this strategy to two main PM strategies-stratified medicine and computational models. Drawing on epistemological work in the philosophy of medicine, we explain why these two methods, while powerful, are neither truly personalised nor, epistemologically speaking, novel strategies. Both are forms of correlational black box. We then argue that the iPSC models would count as a new kind of black box. They would not rely entirely on mechanistic knowledge, and they would utilise correlational evidence in a different way from other strategies-a way that would enable personalised predictions. In arguing that the iPSC models would present a novel method of gaining evidence for clinical practice, we provide an epistemic analysis that can help to inform the practical, regulatory, and ethical challenges of developing an iPSC system.

Efficient Generation of Non-Integration and Feeder-Free Induced Pluripotent Stem Cells from Human Peripheral Blood Cells by Sendai Virus.

BACKGROUND/AIMS: Induced pluripotent stem cells (iPSCs) hold great promise for regenerative medicine, disease modeling, and drug development. Thus, generation of non-integration and feeder-free iPSCs is highly desirable for clinical applications. Peripheral blood mononuclear cells (PBMCs) are an attractive resource for cell reprogramming because of their properties of easy accessibility and the limited invasiveness of blood collection. However, derivation of iPSCs is technically demanding due to the low reprogramming efficiency and nonadherent features of PBMCs. METHODS: iPSCs were generated from PBMCs using non-integrative Sendai viruses carrying the reprogramming factors Oct4, Sox2, Klf4, and cMyc. The derived iPSCs were fully characterized at the levels of gene and protein, and then they were transplanted into immunocompromised mice for evaluation of in vivo differentiation potential. Three types of extracellular substrates (Geltrex, vitronectin, and rhLaminn-521) were tested for their influences on cell reprogramming under feeder-free conditions. We also sought to establish approaches to efficient cell recovery post-thaw and single cell passaging of iPSCs employing Rock inhibitors. RESULTS: iPSCs were efficiently generated from PBMCs under feeder-free conditions. The derived iPSCs proved to be pluripotent and transgene-free. Furthermore, they demonstrated multi-lineage differentiation potentials when transplanted into immunocompromised mice. Among the three substrates, Geltrex and rhLaminin-521 could effectively support the initial cell reprogramming process, but vitronectin failed. However, the vitronectin, similar to Geltrex and rhLaminin-521, could effectively maintain cell growth and expansion of passaged iPSCs. In addition, RevitaCell supplement (RVC) was more potent on cell recovery post-thaw than Y-27632. And RVC and Y-27632 could significantly increase the cell survival when the cells were passaged in single cells, and they showed comparable effectiveness on cell recovery. CONCLUSION: We have successfully derived non-integration and feeder-free human iPSCs from peripheral blood cells, and established effective strategies for efficient cell recovery and single cell passaging. This study will pave the way to the derivation of clinical-grade human iPSCs for future clinical applications.

Treatment of Diabetes Mellitus Using iPS Cells and Spice Polyphenols.

Diabetes mellitus is a chronic disease that threatens human health. The disease is caused by a metabolic disorder of the endocrine system, and long-term illness can lead to tissue and organ damage to the cardiovascular, endocrine, nervous, and urinary systems. Currently, the disease prevalence is 11.4%, the treatment rate is 48.2%, and the mortality rate is 2.7% worldwide. Comprehensive and effective control of diabetes, as well as the use of insulin, requires further study to develop additional treatment options. Here, we reviewed the current reprogramming of somatic cells using specific factors to induced pluripotent stem (iPS) cells capable of repairing islet ß cell damage in diabetes patients to treat patients with type 1 diabetes mellitus. We also discuss the shortcomings associated with clinical use of iPS cells. Additionally, certain polyphenols found in spices might improve glucose homeostasis and insulin resistance in diabetes patients, thereby constituting promising options for the treatment of type 2 diabetes.

Review of the novelties from the 32nd ECTRIMS Congress, 2016, presented at the 9th Post-ECTRIMS Meeting (II). / Revision de las novedades del XXXII Congreso ECTRIMS 2016, presentadas en la IX Reunion Post-ECTRIMS (II).

For the ninth year in a row the Post-ECTRIMS Meeting has been held in Madrid (Spain) with the aim of presenting and discussing the hottest issues debated at the ECTRIMS Congress by renowned specialists in multiple sclerosis in our country. One outcome of this scientific activity, endorsed by the Spanish Neurology Society, is this review article, which is published in two parts. This second part reflects the current controversy over the management of multiple sclerosis, especially as regards the progressive forms and their differential diagnosis. The work presents the latest advances in remyelination, where the use of the micropillar technique in laboratory stands out, and in neuroprotection, which is reviewed through a study of the optic nerve. Anti-CD20 antibodies are a very promising development and we find ourselves before a new mechanism of action and therapeutic target in cells to which little attention has been paid to date. Another notable fact is the high correlation between the levels of neurofilaments in cerebrospinal fluid and in serum, which could make it possible to avoid the use of cerebrospinal fluid as a biological sample in future studies of biomarkers. The review also provides a preview of the advances in clinical research, which will converge in clinical practice in the future, thereby conditioning the steps that should be taken in the therapeutic management of multiple sclerosis.

TITLE: Revision de las novedades del XXXII Congreso ECTRIMS 2016, presentadas en la IX Reunion Post-ECTRIMS (II).Por noveno año consecutivo se ha celebrado en Madrid (España) la Reunion Post-ECTRIMS con el objetivo de presentar y discutir los temas mas debatidos en el congreso ECTRIMS de la mano de reconocidos especialistas en esclerosis multiple de nuestro pais. Fruto de esta reunion cientifica, avalada por la Sociedad Española de Neurologia, se genera este articulo de revision que sale publicado en dos partes. En esta segunda parte se pone de manifiesto la controversia actual en el manejo de la esclerosis multiple, especialmente en cuanto a formas progresivas y diagnostico diferencial se refiere. Se presentan los ultimos avances en remielinizacion, donde destaca el uso de la tecnica con micropilares en el laboratorio, y en neuroproteccion, la cual se revisa a traves del estudio del nervio optico. Los anticuerpos anti-CD20 ofrecen grandes expectativas, y estamos ante un nuevo mecanismo de accion y diana terapeutica en unas celulas a las que les habiamos prestado poca atencion hasta la fecha. Otro hecho destacable es la elevada correlacion entre los niveles de neurofilamentos en el liquido cefalorraquideo y el suero, que podria evitar el uso del liquido cefalorraquideo como muestra biologica en futuros estudios de biomarcadores. Tambien se anticipan los avances en investigacion clinica que en el futuro acabaran convergiendo en la practica clinica, condicionando los pasos que se deberan seguir en el abordaje terapeutico de la esclerosis multiple.

Stem Cell Technology for (Epi)genetic Brain Disorders.

Despite the enormous efforts of the scientific community over the years, effective therapeutics for many (epi)genetic brain disorders remain unidentified. The common and persistent failures to translate preclinical findings into clinical success are partially attributed to the limited efficiency of current disease models. Although animal and cellular models have substantially improved our knowledge of the pathological processes involved in these disorders, human brain research has generally been hampered by a lack of satisfactory humanized model systems. This, together with our incomplete knowledge of the multifactorial causes in the majority of these disorders, as well as a thorough understanding of associated (epi)genetic alterations, has been impeding progress in gaining more mechanistic insights from translational studies. Over the last years, however, stem cell technology has been offering an alternative approach to study and treat human brain disorders. Owing to this technology, we are now able to obtain a theoretically inexhaustible source of human neural cells and precursors in vitro that offer a platform for disease modeling and the establishment of therapeutic interventions. In addition to the potential to increase our general understanding of how (epi)genetic alterations contribute to the pathology of brain disorders, stem cells and derivatives allow for high-throughput drugs and toxicity testing, and provide a cell source for transplant therapies in regenerative medicine. In the current chapter, we will demonstrate the validity of human stem cell-based models and address the utility of other stem cell-based applications for several human brain disorders with multifactorial and (epi)genetic bases, including Parkinson's disease (PD), Alzheimer's disease (AD), fragile X syndrome (FXS), Angelman syndrome (AS), Prader-Willi syndrome (PWS), and Rett syndrome (RTT).

Induced Pluripotent Stem Cell-Derived Cardiomyocytes Provide In Vivo Biological Pacemaker Function.

BACKGROUND: Although multiple approaches have been used to create biological pacemakers in animal models, induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) have not been investigated for this purpose. We now report pacemaker function of iPSC-CMs in a canine model. METHODS AND RESULTS: Embryoid bodies were derived from human keratinocytes, their action potential characteristics determined, and their gene expression profiles and markers of differentiation identified. Atrioventricular blocked dogs were immunosuppressed, instrumented with VVI pacemakers, and injected subepicardially into the anterobasal left ventricle with 40 to 75 rhythmically contracting embryoid bodies (totaling 1.3-2×106 cells). ECG and 24-hour Holter monitoring were performed biweekly. After 4 to 13 weeks, epinephrine (1 µg kg-1 min-1) was infused, and the heart removed for histological or electrophysiological study. iPSC-CMs largely lost the markers of pluripotency, became positive for cardiac-specific markers. and manifested If-dependent automaticity. Epicardial pacing of the injection site identified matching beats arising from that site by week 1 after implantation. By week 4, 20% of beats were electronically paced, 60% to 80% of beats were matching, and mean and maximal biological pacemaker rates were 45 and 75 beats per minute. Maximum night and day rates of matching beats were 53±6.9 and 69±10.4 beats per minute, respectively, at 4 weeks. Epinephrine increased rate of matching beats from 35±4.3 to 65±4.0 beats per minute. Incubation of embryoid bodies with the vital dye, Dil, revealed the persistence of injected cells at the site of administration. CONCLUSIONS: iPSC-CMs can integrate into host myocardium and create a biological pacemaker. Although this is a promising development, rate and rhythm of the iPSC-CMs pacemakers remain to be optimized.

Energy utilization of induced pluripotent stem cell-derived cardiomyocyte in Fabry disease.

BACKGROUND: Fabry disease (FD) is a lysosomal storage disease in which glycosphingolipids (GB3) accumulate in organs of the human body, leading to idiopathic hypertrophic cardiomyopathy and target organ damage. Its pathophysiology is still poorly understood. OBJECTIVES: We aimed to generate patient-specific induced pluripotent stem cells (iPSC) from FD patients presenting cardiomyopathy to determine whether the model could recapitulate key features of the disease phenotype and to investigate the energy metabolism in Fabry disease. METHODS: Peripheral blood mononuclear cells from a 30-year-old Chinese man with a diagnosis of Fabry disease, GLA gene (IVS4+919G>A) mutation were reprogrammed into iPSCs and differentiated into iPSC-CMs and energy metabolism was analyzed in iPSC-CMs. RESULTS: The FD-iPSC-CMs recapitulated numerous aspects of the FD phenotype including reduced GLA activity, cellular hypertrophy, GB3 accumulation and impaired contractility. Decreased energy metabolism with energy utilization shift to glycolysis was observed, but the decreased energy metabolism was not modified by enzyme rescue replacement (ERT) in FD-iPSCs-CMs. CONCLUSION: This model provided a promising in vitro model for the investigation of the underlying disease mechanism and development of novel therapeutic strategies for FD. This potential remedy for enhancing the energetic network and utility efficiency warrants further study to identify novel therapies for the disease.

Human induced pluripotent stem cells: A disruptive innovation.

This year (2016) will mark the 10th anniversary of the discovery of induced pluripotent stem cells (iPSCs). The finding that the transient expression of four transcription factors can radically remodel the epigenome, transcriptome and metabolome of differentiated cells and reprogram them into pluripotent stem cells has been a major and groundbreaking technological innovation. In this review, we discuss the major applications of this technology that we have grouped in nine categories: a model to study cell fate control; a model to study pluripotency; a model to study human development; a model to study human tissue and organ physiology; a model to study genetic diseases in a dish; a tool for cell rejuvenation; a source of cells for drug screening; a source of cells for regenerative medicine; a tool for the production of human organs in animals.

Induced pluripotent stem cells in Parkinson's disease: scientific and clinical challenges.

Induced pluripotent stem cells (iPSCs), which greatly circumvent the ethical issue of human embryonic stem cells (ESCs), can be induced to differentiate to dopaminergic (DA) neurons, and hence be used as a human disease model for Parkinson's disease (PD). iPSCs can be also utilised to probe the mechanism, and serve as an 'in vivo' platform for drug screening and for cell-replacement therapies. However, any clinical trial approaches should be extensively supported by validated robust biological evidence (based on previous experience with fetal mesencephalic transplantation), in particular, the production and selection of the 'ideal' neurons (functional units with no oncological risk), together with the careful screening of appropriate candidates (such as genetic carriers), with inbuilt safeguards (safety studies) in the evaluation and monitoring (functional neuroimaging of both DA and non-DA system) of trial subjects. While iPSCs hold great promise for PD, there are still numerous scientific and clinical challenges that need to be surmounted before any clinical application can be safely introduced.

iPSC-based drug screening for Huntington's disease.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder, caused by an expansion of the CAG repeat in exon 1 of the huntingtin gene. The disease generally manifests in middle age with both physical and mental symptoms. There are no effective treatments or cures and death usually occurs 10-20 years after initial symptoms. Since the original identification of the Huntington disease associated gene, in 1993, a variety of models have been created and used to advance our understanding of HD. The most recent advances have utilized stem cell models derived from HD-patient induced pluripotent stem cells (iPSCs) offering a variety of screening and model options that were not previously available. The discovery and advancement of technology to make human iPSCs has allowed for a more thorough characterization of human HD on a cellular and developmental level. The interaction between the genome editing and the stem cell fields promises to further expand the variety of HD cellular models available for researchers. In this review, we will discuss the history of Huntington's disease models, common screening assays, currently available models and future directions for modeling HD using iPSCs-derived from HD patients. This article is part of a Special Issue entitled SI: PSC and the brain.

Current Neurogenic and Neuroprotective Strategies to Prevent and Treat Neurodegenerative and Neuropsychiatric Disorders.

The adult central nervous system is commonly known to have a very limited regenerative capacity. The presence of functional stem cells in the brain can therefore be seen as a paradox, since in other organs these are known to counterbalance cell loss derived from pathological conditions. This fact has therefore raised the possibility to stimulate neural stem cell differentiation and proliferation or survival by either stem cell replacement therapy or direct administration of neurotrophic factors or other proneurogenic molecules, which in turn has also originated regenerative medicine for the treatment of otherwise incurable neurodegenerative and neuropsychiatric disorders that take a huge toll on society. This may be facilitated by the fact that many of these disorders converge on similar pathophysiological pathways: excitotoxicity, oxidative stress, neuroinflammation, mitochondrial failure, excessive intracellular calcium and apoptosis. This review will therefore focus on the most promising achievements in promoting neuroprotection and neuroregeneration reported to date.

Human induced pluripotent stem cells in Parkinson's disease: A novel cell source of cell therapy and disease modeling.

Human induced pluripotent stem cells (hiPSCs) and human embryonic stem cells (hESCs) are two novel cell sources for studying neurodegenerative diseases. Dopaminergic neurons derived from hiPSCs/hESCs have been implicated to be very useful in Parkinson's disease (PD) research, including cell replacement therapy, disease modeling and drug screening. Recently, great efforts have been made to improve the application of hiPSCs/hESCs in PD research. Considerable advances have been made in recent years, including advanced reprogramming strategies without the use of viruses or using fewer transcriptional factors, optimized methods for generating highly homogeneous neural progenitors with a larger proportion of mature dopaminergic neurons and better survival and integration after transplantation. Here we outline the progress that has been made in these aspects in recent years, particularly during the last year, and also discuss existing issues that need to be addressed.

Present and future challenges of induced pluripotent stem cells.

Growing old is our destiny. However, the mature differentiated cells making up our body can be rejuvenated to an embryo-like fate called pluripotency which is an ability to differentiate into all cell types by enforced expression of defined transcription factors. The discovery of this induced pluripotent stem cell (iPSC) technology has opened up unprecedented opportunities in regenerative medicine, disease modelling and drug discovery. In this review, we introduce the applications and future perspectives of human iPSCs and we also show how iPSC technology has evolved along the way.