CISD2 ensures adequate ER-mitochondrial coupling, critically supporting mitochondrial function in neurons.

The existence of cancer stem cell (CSC) has been considered as one of the important reason as to why patients have a poor prognosis. However, heterotopic transplantation of embryonic stem cells and induced pluripotent stem cells has been shown to form teratoma, but not malignant teratoma. Since the microenvironment niche is playing a significant role for the proper differentiation of stem cells, the cancerous niche should drive stem cells into malignant cells in vivo. According to this hypothesis, we tried to generate cancer cells from human induced pluripotent stem (hiPS) cells. For the conversion into CSC, the conditioned medium from different human cancer cell lines was collected from confluent dishes and filtered using 0.22 micrometer filter. Then, hiPS cells, without MEF feeder cells, were maintained in the conditioned medium (CM) in the ratio of 1:1. The medium was changed every day with CM for 4 weeks. hiPS cells with the complete medium were used as control. For transplantation studies, 10^4 cells were suspended in HBSS and were xenotransplantated into NOD-SCID mice. After 3 months, tumors were excised and fixed in 10% neutral formalin buffer solution, or subjected to primary culture. The converted cells and primary cultured cells formed spheroids in suspension culture, and had tumorigenicity in vivo. The stemness of living cells was checked under fluorescent microscopy observation with rBC2LCN-FITC staining. The RNAs were extracted from converted cells and microarray analysis was perfomed. The RNA expression patterns of cell lines were visualized by sphered self-organizing map (sSOM) analysis. The sSOM analysis perfomed based upon various parameters shows the converted CSCs can be characterized into various cell types. Utilizing this method, we successfully established two different hiPS-CSC lines using CM from A172 and RERF-LC-KJ. The comprehensive understanding of cancer could be realized as the heterogeneity of cancer tissues is clarified and their component cells are identified. This study will lead to the development of the true personalized therapy of cancer in the future. Citation Format: Tomonari Kasai, Kenta Hoshikawa, Shuto Takejiri, Masashi Ikeda, Kazuki Kumon, Anna Sanchez Calle, Arun Vaidyanath, Akifumi Mizutani, Chen Ling, Masaharu Seno. Derivation of a model of cancer stem cell from human induced pluripotent stem cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-144. doi:10.1158/1538-7445.AM2015-LB-144

Mitochondrial bioenergetics and neurodegeneration: a paso doble

BackgroundRecent studies have found that p53 and its' associated cell cycle pathways are major inhibitors of human induced pluripotent stem (iPS) cell generation. In the same family as p53 is p73, which shares sequence similarities with p53. However, p73 also has distinct properties of its own, such as two alternative promoters to express transactivation of p73 (TAp73) and N terminal deleted p73 (DNp73). Functionally, TAp73 acts similarly to p53 in tumor suppression. However, DNp73, on the other hand acts as an oncogene to suppress p53 and p73 induced apoptosis. Therefore, how can p73 have opposing roles in human iPS cell generation?ResultsTranscription factors, Oct4, Sox2, Klf4 and cMyc (4TF, Yamanaka factors) are used as basal conditions to generate iPS cells. In addition, the factor of DNp73(actually alpha splicing DNp73, DNp73α) is used to generate iPS cells. The experiment found that the addition of DNp73 gene increases human iPS cell generation efficiency by 12.6 folds in comparison to human fibroblast cells transduced with only the basal conditions. Also, iPS cells generated with DNp73 expression are more resistant to in vitro and in vivo differentiation.ConclusionsThis study found DNp73, a family member of p53, is also involved in the human iPS cell generation. Specifically, that the involvement of DNp73 generates iPS cells that are more resistant to in vitro and in vivo differentiation. Therefore, this data may prove to be useful in future developmental studies and cancer researches.

See related article, pages 648–656 The ability to generate induced pluripotent stem (iPS) cells from somatic cells by the overexpression of a limited number of stem cell-related genes has generated great excitement and interest in the biomedical research community including cardiovascular researchers. The pioneering study by Yamanaka and colleagues showing that overexpression of Oct3/4 , Sox2 , Klf4 , and c-Myc could reprogram mouse fibroblasts to a pluripotent state similar to that of embryonic stem (ES) cells opened major new avenues of research.1 This epigenetic reprogramming was rapidly extrapolated to the human system using either the same combination of reprogramming factors or a slightly different combination of transgenes ( OCT4 , NANOG , SOX2 , LIN28 ).2–4 Like embryonic stem (ES) cells, iPS cells can be used for basic developmental biology research and also as a cell source to generate theoretically unlimited quantities of desired cell types such as cardiomyocytes. Such differentiated cells types can be used in a wide range of basic research studies and potentially in clinical applications, which not only include cellular therapies but also drug discovery and safety testing. One appealing aspect of human iPS cells compared to human ES cells is that they can be more readily generated without specialized expertise and access to human embryos, which also avoids the ethical challenges associated with human embryo research. Potentially the most powerful advantage of iPS cells over ES cells is that they can be generated from any patient to produce genetically identical pluripotent cells that can create human disease models or generate patient-specific cells for therapy. Already a number of iPS cell human disease models have been generated,5,6 and proof-of-principle iPS cellular therapies have been pioneered in mouse models.7–9 Despite the speed at which the iPS cell field is racing forward, we …

Efficient Reprogramming of Human Cord Blood CD34+ Cells Into Induced Pluripotent Stem Cells With OCT4 and SOX2 Alone

The mitochondrial inner membrane (IM) serves as the site for ATP production by hosting the oxidative phosphorylation complex machinery most notably on the crista membranes. Disruption of the crista structure has been implicated in a variety of cardiovascular and neurodegenerative diseases. Here, we characterize ChChd3, a previously identified PKA substrate of unknown function (Schauble, S., King, C. C., Darshi, M., Koller, A., Shah, K., and Taylor, S. S. (2007) J. Biol. Chem. 282, 14952–14959), and show that it is essential for maintaining crista integrity and mitochondrial function. In the mitochondria, ChChd3 is a peripheral protein of the IM facing the intermembrane space. RNAi knockdown of ChChd3 in HeLa cells resulted in fragmented mitochondria, reduced OPA1 protein levels and impaired fusion, and clustering of the mitochondria around the nucleus along with reduced growth rate. Both the oxygen consumption and glycolytic rates were severely restricted. Ultrastructural analysis of these cells revealed aberrant mitochondrial IM structures with fragmented and tubular cristae or loss of cristae, and reduced crista membrane. Additionally, the crista junction opening diameter was reduced to 50% suggesting remodeling of cristae in the absence of ChChd3. Analysis of the ChChd3-binding proteins revealed that ChChd3 interacts with the IM proteins mitofilin and OPA1, which regulate crista morphology, and the outer membrane protein Sam50, which regulates import and assembly of β-barrel proteins on the outer membrane. Knockdown of ChChd3 led to almost complete loss of both mitofilin and Sam50 proteins and alterations in several mitochondrial proteins, suggesting that ChChd3 is a scaffolding protein that stabilizes protein complexes involved in maintaining crista architecture and protein import and is thus essential for maintaining mitochondrial structure and function.

SummaryInduced pluripotent stem cells (iPSCs) are valuable in disease modeling because of their potential to expand and differentiate into virtually any cell type and recapitulate key aspects of human biology. Functional genomics are genome-wide studies that aim to discover genotype-phenotype relationships, thereby revealing the impact of human genetic diversity on normal and pathophysiology. In this review, we make the case that human iPSCs (hiPSCs) are a powerful tool for functional genomics, since they provide an in vitro platform for the study of population genetics. We describe cutting-edge tools and strategies now available to researchers, including multi-omics technologies, advances in hiPSC culture techniques, and innovations in drug development. Functional genomics approaches based on hiPSCs hold great promise for advancing drug discovery, disease etiology, and the impact of genetic variation on human biology.

Promise of Human Induced Pluripotent Stem Cells in Skin Regeneration and Investigation

Autophagy is a conserved degradative process that is crucial for cellular homeostasis and cellular quality control via the selective removal of subcellular structures such as mitochondria. We demonstrate that a regulatory link exists between mitochondrial function and autophagy in Saccharomyces cerevisiae. During amino-acid starvation, the autophagic response consists of two independent regulatory arms-autophagy gene induction and autophagic flux-and our analysis indicates that mitochondrial respiratory deficiency severely compromises both. We show that the evolutionarily conserved protein kinases Atg1, target of rapamycin kinase complex I, and protein kinase A (PKA) regulate autophagic flux, whereas autophagy gene induction depends solely on PKA. Within this regulatory network, mitochondrial respiratory deficiency suppresses autophagic flux, autophagy gene induction, and recruitment of the Atg1-Atg13 kinase complex to the pre-autophagosomal structure by stimulating PKA activity. Our findings indicate an interrelation of two common risk factors-mitochondrial dysfunction and autophagy inhibition-for ageing, cancerogenesis, and neurodegeneration.

), during heightened metabolicdemand (i.e. contraction) there is anessential requirement for rapid andsustained ATP production, a role fulfilledprimarilybymitochondria.Assuch,skeletalmuscle cells are densely populated withthese complex organelles.Withanincreasingprevalenceofinactivityand obesity, type 2 diabetes has become amajor public health concern. Given theircentral role in energy production, it isperhaps not surprising that mitochondrialdysfunction has been implicated inthe aetiology of skeletal muscle insulinresistance, a precursor of frank diabetes.Furthermore,interventionswhichstimulateskeletal muscle mitochondrial biogenesiscan improve insulin sensitivity in obeseand/or insulin resistant individuals. Whileit seems clear that a reduction inskeletal muscle mitochondrial

Protocols have been established to direct the differentiation of human induced pluripotent stem (iPS) cells into nephron progenitor cells and organoids containing many types of kidney cells, but it has been difficult to direct the differentiation of iPS cells to form specific types of mature human kidney cells with high yield. Here, we describe a detailed protocol for the directed differentiation of human iPS cells into mature, post-mitotic kidney glomerular podocytes with high (>90%) efficiency within 26 d and under chemically defined conditions, without genetic manipulations or subpopulation selection. We also describe how these iPS cell-derived podocytes may be induced to form within a microfluidic organ-on-a-chip (Organ Chip) culture device to build a human kidney Glomerulus Chip that mimics the structure and function of the kidney glomerular capillary wall in vitro within 35 d (starting with undifferentiated iPS cells). The podocyte differentiation protocol requires skills for culturing iPS cells, and the development of a Glomerulus Chip requires some experience with building and operating microfluidic cell culture systems. This method could be useful for applications in nephrotoxicity screening, therapeutic development, and regenerative medicine, as well as mechanistic study of kidney development and disease.

This unit describes how to generate human induced pluripotent stem (iPS) cells and evaluate the qualities of the generated iPS cells. The methods for establishment and maintenance of human iPS cells are similar to those for mouse iPS cells but not identical. In addition, these protocols include excellent procedures for passaging and cryopreservation of human iPS cells established by ES cell researchers, which result in an easy way to culture human iPS cells. Moreover, we include methods for characterizing iPS cells for further research. RT-PCR and immunocytochemistry for detection of pluripotent cell markers, embryoid body differentiation, and teratoma differentiation are used to determine pluripotency in vitro and in vivo, respectively.

Hematopoietic Development From Human Induced Pluripotent Stem Cells.

Introduction: Cardiomyocytes are highly vulnerable to anthracycline-induced toxicity, which may lead to heart failure. This includes doxorubicin, which is a commonly used chemotherapeutic agent. Although mitochondrial function has been implicated as a mechanism of anthracycline-induced toxicity in rodent heart cells, the precise genes that regulate this response in humans remain to be elucidated. We hypothesized that doxorubicin significantly alters expression of mitochondrial genes in human cardiomyocytes, which impairs mitochondrial function. Methods: Human inducible pluripotent stem cell (iPSC)-derived cardiomyocytes were treated with doxorubicin or left untreated for control to assess changes in gene expression using RNAseq. A total of 169 genes involved in mitochondrial function, as defined by Ingenuity Pathway Analysis and KEGG, were analyzed for significant differences between untreated and treated conditions using DESeq2 and GenePattern 2.0. Mitochondrial respiration was measured in control and doxorubicin-treated cells using the Seahorse Bioscience XFe96 Cell Mito Stress Test kit. We used a Spearman's partial correlation coefficient analysis to correlate gene expression levels with mitochondrial basal respiration, ATP production, maximal respiration, and spare respiratory capacity for untreated and doxorubicin-treated iPSC-cardiomyocytes. Results: Of the 169 mitochondrial genes analyzed, we identified 25 genes that were significant in our global differential expression analysis across all conditions (P<0.05). Seven of these genes (ATP5D, COX5A, CYC1, HSD17B10, NDUFB10, NDUFS8, UQCRC1) remained significant in pairwise analyses between control and doxorubicin treated cells. We observed a decrease in mitochondrial respiration following treatment with doxorubicin. Maximal respiration (r=-0.929; P=0.022) and spare respiratory capacity (r=-0.98;P=0.0025) negatively correlated with NDUFS8 expression in doxorubicin-treated iPSC-cardiomyocytes. Conclusion: Our findings underscore a role for mitochondrial function in the development of doxorubicin-induced cardiotoxicity and implicate specific genes in this process. Doxorubicin-altered gene expression in cardiomyocytes may provide insight into how impaired mitochondrial function leads to heart failure in cancer survivors. Citation Format: Monica E. Reyes, Rashida Callender, Jianzhong Ma, Megan L. Grove, Alanna C. Morrison, Michelle A. Hildebrandt. Doxorubicin-induced cardiotoxicity in iPSC-cardiomyocytes: Altered mitochondrial gene expression and function [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 892.

Wolfram syndrome 2 (WFS2) is a premature aging syndrome caused by an irreversible mitochondria-mediated disorder. Cisd2, which regulates mitochondrial electron transport, has been recently identified as the causative gene of WFS2. The mouse Cisd2 knockout (KO) (Cisd2(-/-)) recapitulates most of the clinical manifestations of WFS2, including growth retardation, osteopenia, and lordokyphosis. However, the precise mechanisms underlying osteopenia in WFS2 and Cisd2 KO mice remain unknown. In this study, we collected embryonic fibroblasts from Cisd2-deficient embryos and reprogrammed them into induced pluripotent stem cells (iPSCs) via retroviral transduction with Oct4/Sox2/Klf4/c-Myc. Cisd2-deficient mouse iPSCs (miPSCs) exhibited structural abnormalities in their mitochondria and an impaired proliferative capability. The global gene expression profiles of Cisd2(+/+), Cisd2(+/-), and Cisd2(-/-) miPSCs revealed that Cisd2 functions as a regulator of both mitochondrial electron transport and Wnt/β-catenin signaling, which is critical for cell proliferation and osteogenic differentiation. Notably, Cisd2(-/-) miPSCs exhibited impaired Wnt/β-catenin signaling, with the downregulation of downstream genes, such as Tcf1, Fosl1, and Jun and the osteogenic regulator Runx2. Several differentiation markers for tridermal lineages were globally impaired in Cisd2(-/-) miPSCs. Alizarin red S staining and flow cytometry analysis further revealed that Cisd2(-/-) miPSCs failed to undergo osteogenic differentiation. Taken together, our results, as determined using an miPSC-based platform, have demonstrated that Cisd2 regulates mitochondrial function, proliferation, intracellular Ca(2+) homeostasis, and Wnt pathway signaling. Cisd2 deficiency impairs the activation of Wnt/β-catenin signaling and thereby contributes to the pathogeneses of osteopenia and lordokyphosis in WFS2 patients.