Feeder-free Culture Research Articles

Serum- and Feeder-Free Culture of Juvenile Monkey Female Germline Stem Cells and Testosterone Regulation of their Self-Renewal.

Female germline stem cells (FGSCs) have been found in mouse, rat, pig, sheep and human ovaries. However, there is no information on the isolation or long-term culture of FGSCs from non-human primates. Here, we identified the presence of FGSCs in the ovaries of juvenile (3-4-year-old) cynomolgus monkeys using DDX4 and Ki67 double immunofluorescence. Then, a long-term serum- and cell feeder-free culture system for these FGSCs was used to establish a cell line, and its biological characteristics were analyzed. We found that testosterone promoted self-renewal of the cells. This study confirmed for the first time the presence of FGSCs in the ovary of non-human primates. This culture system and cell line will be of great significance for research in medicine and reproductive biology.

P-083: Rejuvenated BCMA-specific CD8+ Cytotoxic T lymphocytes derived from induced pluripotent stem cells for treatment of Multiple Myeloma

<h3>Background</h3> This study reports on the reprogramming of B-Cell Maturation Antigen (BCMA)-specific CD8+ cytotoxic T lymphocytes (CTL) to induced pluripotent stem cells (iPSC) and their differentiation into rejuvenated antigen-specific CD8+ CTL as a potential therapeutic option to effectively treat cancer patients. Along with characterization of BCMA-specific iPSC by key stem cell markers, pluripotency potential and normal karyotypes, we further detected their polarization into mesoderm development associated with activation of transcriptional regulators SNAI2, TBX3, PLVAP, HAND1 and CDX2 during embryoid body formation. BCMA-specific iPSC clones utilized distinctive commitment pathways during T cells re-differentiation. RNAseq analyses of the "iPSC committed to rejuvenated memory CD8+ T cells" showed unique transcriptional profiles as evidenced by upregulation of transcriptional regulators determining CD4/CD8 T cell differentiation ratio, memory CTL formation, NF-kappa-B / JNK pathway activation, and cytokine transporter/cytotoxic mediator development. In parallel, regulators controlling B and T cell interactions or CD4+ Th cells and inhibitory receptor development were downregulated. The rejuvenated CD8+ BCMA-specific CTL re-differentiated from the iPSC demonstrated (1) mature T cell phenotype and highly enriched central and effector memory T cells without induction of checkpoint molecules; (2) high proliferation and poly-functional anti-myeloma activities in an antigen-specific and HLA-A2-restricted manner; (3) specific immune recognition of cognate HLA-A2 heteroclitic BCMA72-80 (YLMFLLRKI) peptide; and (4) distinct sole clonotype for T cell receptor. Furthermore, the specific iPSC clones maintained their differentiation potential into CD8+ T cells upon sub-cloning or long-term culture under feeder-free culture conditions. <h3>Conclusion</h3> In conclusion, these results establish a framework for iPSC-based regenerative medicine to provide rejuvenated and highly functional memory CD8+ BCMA-specific CTL as an adoptive immunotherapy to improve patient outcome in multiple myeloma.

337 DermaCult™, a Serum- and BPE-free Medium Supporting Long-term Feeder-free Expansion of Primary Human Epidermal Keratinocytes that Retain Their Differentiation Potential at Air Liquid Interface

Primary human epidermal keratinocytes (HEKs) typically undergo growth arrest at approximately 15 - 30 population doublings (PDs) when maintained in traditional feeder-free culture medium formulations. To circumvent this early senescence, we developed DermaCult™, a serum- and BPE-free medium that promotes long-term growth (> 30 PDs) of HEKs while maintaining their air liquid interface (ALI) differentiation potential. To measure cell expansion over the entire lifespan of the culture, HEKs derived from either neonatal or adult skin were thawed and seeded onto uncoated tissue cultureware at a density of 1 - 2.5 x 103 cells/cm2, and passaged when cultures reached approximately 50 - 70% confluence. At various time points, keratinocytes were analyzed by qPCR and flow cytometry to detect expression of basal and differentiated cell markers. In separate cultures, keratinocytes were also differentiated by increasing the calcium concentration in feeder- free monolayer culture or establishing ALI culture. Keratinocytes derived from adult or neonatal skin and cultured in DermaCult™ proliferated between 50 - 70 or >70 PDs before undergoing senescence, respectively (n=4). In monolayer cultures, keratinocytes predominantly maintained a cobblestone morphology, expressed basal cell markers (TP63, KRT14, ITGA6), and were devoid of suprabasal marker KRT10 (n=4). Induction of differentiation resulted in the expression of KRT10, LOR, and formation of ZO-1 tight junctions, with concomitant down-regulation of basal markers TP63 and KRT14. In ALI culture, HEKs generated a stratified epithelium with the appropriate cellular architecture and expression of markers similar to their in vivo counterparts. In summary, we have developed an improved and first BPE-free medium for primary HEKs culture that promotes greater expansion of HEKs and maintenance of their differentiation potential at later passages.

P–803 Novel culture conditions for the improvement of the in vitro expansion of human male fetal germ cells

Abstract Study question Do different ECMs/substrates and growth media culture conditions improve in vitro male human primordial germ cell (hPGC) expansion? Summary answer We achieved in vitro expansion improvement of male hPGCs with specific growth factors such as LIF, EGF, FGF2 and GDNF on gelatin- and vitronectin-coating cultures. What is known already PGCs are the precursors of male and female gametes, which are specified during early mammalian post-implantation embryonic development. PGCs undergo sequential cell divisions to differentiate into pro-spermatogonia (pSPG). In vitro propagation of pSPG could be important to understand the transition to spermatogonial stem cells (SSCs), important for fertility preservation in patients with infertility. Here, we aimed at performing a comparative analysis on in vitro feeder-free culture systems, based on different extracellular matrix (ECM) and growth media culture conditions, to support the expansion of the male germline stem cell populations using second trimester human male gonads as primary material. Study design, size, duration We collected human 2nd trimester male fetal gonads from elective abortions. Male gonads were dissected in saline solution (0.9% NaCl) and were either fixed overnight in 4% paraformaldehyde (PFA) for immunohistochemistry or disaggregated by enzymatic digestion for in vitro culture. Participants/materials, setting, methods After differential plating, fetal cells were cultured for 6 days. Disaggregated gonads were cultured with two different growing media (Medium 1 supplemented with LIF, EGF, FGF–2 and GDNF and Medium 2 supplemented with RA, BMP 4 and Activin A) on gelatin, laminin, vitronectin or matrigel coated plates. Cultured cells were immunostained, quantified for the expression of DDX4 and POU5F1 after 3 days (D3) and 6 days (D6) of culture. Main results and the role of chance We pursued to evaluate whether germ cells dissociated from a pool of male fetal gonads could propagate in vitro when cultured for D6 in different conditions. We observed that expansion of POU5F1-positive early PGCs and DDX4-positive late PGCs was only observed when cells were plated on gelatin or vitronectin and cultured with Medium 1, containing the growth factors LIF, EGF, FGF2 and GDNF. However, a reduced percentage of PGCs was observed in all four different coatings when grown with Medium 2, containing RA, BMP4 and Activin A. We analyzed the relative expression of the PGC markers POU5F1, DDX4 and MAGEA4 in histological sections of gonads from embryos at 18.5 weeks of gestation. Two populations of hPGCs were observed: ∼10–30% of the gonadal cells expressed solely DDX4 (late PGCs), whereas less than 10% of gonadal cells expressed POU5F1 (early PGCs). SOX9 and STARD1 expression was evaluated, confirming the presence of Sertoli cells and Leydig cells, respectively. Limitations, reasons for caution Due to the limited and difficulty to obtain human fetal tissue, a limited number of samples were used. Wider implications of the findings: We expanded human male fetal germ cells in vitro for D6 on gelatin and vitronectin coated plates with Medium 1, containing growth factors LIF, EGF, FGF2 and GDNF. Our findings provide a 2D culture system to expand hPGCs that could be useful to study propagation to pSPGs and eventually SSCs. Trial registration number Not applicable

Improved ES Cell-Derived Erythroid Cell Generation with Robust β-Globin Production through ES-Sacs

In vitro erythroid cell generation represents an important model and potential therapeutic strategy for hemoglobin disorders, including sickle cell disease. Traditional methods for erythroid cell generation from human embryonic stem cells (hESCs) via embryoid body or monolayer culture methods result in mainly ε-globin and γ-globin production with very low amounts of β-globin. Recently, we have demonstrated hESC-derived erythroid cell generation via hemangioblast-like ES-sacs, allowing for definitive β-globin production at detectable protein levels by HPLC (Stem Cells, 2016).In this study, we sought to improve ES-sac generation using defined serum-free Knockout Serum Replacement (KSR) instead of fetal bovine serum (FBS), to allow for more precise optimization and variability reduction among FBS lots. We investigated ES-sac generation using VEGF by comparing 15%FBS-based media (Control) and serum-free 20%KSR-based media (MEF-KSR) on C3H feeder cells using H1 hESCs (maintained on MEF feeder cells). In addition, we compared feeder-free hESCs (maintained on Matrigel) with on-feeder hESCs using both KSR-based media (MT-KSR) and FBS-based media (MT-FBS) to determine whether feeder-free hESCs culture produces a more uniform cell population. 15 days after ES-sac generation, hematopoietic-like suspension cells were differentiated to erythroid cells with erythropoietin for an additional 15 days (total 30 days). After ES-sac generation (day 15), we counted ES-sac numbers (from 1x10e5 hESCs), and analyzed definitive hematopoietic precursor cells (HPCs, CD34+CD45+), erythromegakaryocyte precursors (EMPs, CD235a+CD41a+), and primitive erythrocytes (PEs; CD235a+CD34-) by flow cytometry. After erythroid differentiation (day 30), we evaluated erythroid cell yields (from 1x10e5 hESCs) and globin protein levels by HPLC.We observed similar amounts of ES-sacs (62±48 vs 40±30, ns) at day 15 and erythroid cell yields (32±19 vs 41±12 x10e5, ns) at day 30 as well as similar levels of β-globin (13±10 vs 19±9%, ns) and ε-globin (21±10 vs 12±4%, ns) between MEF-KSR and Control. The MEF-KSR results in similar percentages of HPCs (4±2 vs 7±5%, ns), EMPs (9±6 vs 14±14%, ns), and PEs (25±11 vs 36±13%, ns) in ES-sacs, suggesting that KSR can replace FBS allowing for similar ES-sac generation with erythroid differentiation derived from on-feeder hESCs.When using feeder-free hESCs, ~10-fold greater amounts of ES-sacs (564±458 and 208±138 vs 40±30) and erythroid cell yields (180±134, p<0.01 and 71±6 vs 41±12 x10e5) were obtained in MT-KSR (p<0.01) but not MT-FBS (ns), compared to Control (Figure). Lower percentages of HPCs (2±2, p<0.01 and 6±4, ns vs 7±5%), EMPs (7±4 and 7±2 vs 14±14%, ns), and PEs (22±10 and 20±3 vs 36±13%, p<0.05) were observed in MT-KSR and MT-FBS, while high levels of β-globin (23±5 and 23±4 vs 19±9%, ns) and low levels of ε-globin (14±5 and 8±3 vs 12±4%, ns) were detected at similar protein levels among all groups (Figure). These data demonstrate that our serum-free culture (MT-KSR) allows for greater amounts of ES-sac generation, resulting in more erythroid cell yields with high β-globin production.To evaluate whether KSR-based media improve ES-sac colony formation in the initial step or ES-sac structure production in the maturation step, we investigated either KSR- or FBS-based media in the first half and second half of ES-sac generation from feeder-free hESCs: switched from KSR to FBS (KSR-FBS) or FBS to KSR (FBS-KSR), as compared to Control (FBS-based media only). We observed a trend to higher amounts of ES-sac generation (157±74 and 88±16 vs 48±20, ns), lower percentage of HPCs (1±1, p<0.05 and 6±1, ns vs 4±2%), higher percentage of EMPs (10±2, p<0.05 and 1±1, ns vs 5±1%), and higher percentage of PEs (27±7, p<0.01 and 8±2, ns vs 16±1%,) were observed in KSR-FBS (similar to KSR only) but not in FBS-KSR (similar to FBS only). These data suggest that KSR-based media allows for improved ES-sac colony formation in the initial step, while FBS may increase emergence of definitive hematopoietic precursors during ES-sac generation.In summary, we demonstrate improved ES-sac colony formation with serum-free culture from feeder-free hESCs producing erythroid cell yields with high β-globin production (up to 23%) detectable at the protein level. Further improvement of hESC-derived erythroid cell generation might be achieved by additional nutrients or cytokines in defined KSR-based media. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

The Effect of the MK0339 Neutrophil Elastase Inhibitor on Proliferation and Maturation of iPSC Derived from Patients with ELANE, TCIRG1 and Whim Syndrome Associated Neutropenia

Genetic neutropenias are heterogeneous group of hematological diseases characterized by impaired survival and maturation of myeloid precursors in bone marrow. G-CSF and HSCT are currently the only effective treatment options. MK-0339 is a potent, cell permeable, orally absorbed inhibitor of neutrophil elastase (NE), previously investigated in preclinical and clinical studies by Merck/DuPont as a potential anti-inflammatory drug. We have previously reported that MK-0339 increases neutrophil proliferation in cellular models of ELANE associated neutropenia (2016 [ASH Annual Meeting Abstracts] Blood. 2016;128:406; 2017 J Leuk Biol [in press]). To examine the specificity of these responses, we investigated the effects of MK-0339 on iPSCs from healthy volunteers and compared its effects on differentiation of iPSC derived from patients with ELANE, TCIRG-1 and CXCR4 associated neutropenia.We generated induced pluripotent stem cells (iPSC) from dermal fibroblasts from healthy volunteers and neutropenic patients harboring ELANE, TCIRG1 and CXCR4 mutations and developed a feeder free, reproducible and efficient protocol for myeloid differentiation.In our initial experiments, we observed that iPSC lines derived from patients with ELANE mutations (P139L and G214R) consistently grew much slower and formed much smaller colonies than the controls using both mTeSR1/matrigel and DEF-CS feeder free culture medium systems. We observed more than 3-fold growth reduction of patient derived lines compared to healthy volunteers.We next tested the effects of MK-0339 under the same culture conditions. Growth of control and ELANE patient cell lines was enhanced, and the cells appeared more robust, after addition of 1uM MK-0339. We were surprised to see a similar proliferative effect (~40% increase) with Ramos (human Burkitt's lymphoma cell line) cells cultured in the presence of 1uM MK-0339, although neither the Ramos cells nor the ELANE iPSCs had detectable levels of ELANE expression. The enhanced growth of control and patient iPSCs and the results with Ramos cells suggested that the effects of MK-0339 are not solely mediated via inhibition of NE.We next compared myeloid differentiation and CD34+ cell proliferation of iPSC from patients with ELANE, TCIRG1 and CXCR4 associated neutropenia in HPC expansion medium, using granulocytic differentiation markers and flow cytometry. Myeloid maturation was impaired and inefficient for both ELANE (P139L and G214R) patient derived cell lines. Myeloid differentiation of the TCIRG1 patient derived was also impaired. Introduction of MK-0339 restored the impaired myeloid differentiation capacity of both ELANE and TCIRG1 positive patient derived cell lines. An iPSC line derived from a WHIM (CXCR4 mutation) patient appeared to have normal maturation and proliferation. Western blot analysis revealed elevated levels of endoplasmic reticulum chaperone GRP78/BiP in ELANE and TCIRG1 mutant cell lines which was corrected by MK-0339 treatment.These studies demonstrate heretofore unreported proliferative effects of MK-0339 on cell lines not expressing neutrophil elastase. They suggest important mechanisms beyond enzyme inhibition to account for these findings. Although preliminary, we believe that this work suggests that MK-0339 may be a novel, oral therapy for both ELANE and non-ELANE associated neutropenia. DisclosuresDale:University of Washington: Employment, Research Funding; National Institutes of Health: Research Funding; WedMD/Medscape: Membership on an entity's Board of Directors or advisory committees; Wolter Kluwer: Other: Editor, Current Opinions in Hematology; Philips: Research Funding; X4Pharma: Research Funding; Shire: Other: Independent Review Board; Omeros: Other: DSMB; Coherus: Consultancy; Boheringer-Ingelheim: Consultancy; Prolong: Consultancy; Hospira: Consultancy; Genkyotex: Other: DSMB (work completed 6/2015); Genzyme (now owned by Sanofi-Aventis): Consultancy, Patents & Royalties, Research Funding; Cellerant: Membership on an entity's Board of Directors or advisory committees; Sanofi Aventis: Consultancy, Editor, Current Opinions in Hematology, Honoraria; Amgen: Consultancy, Research Funding; American College of Physicians: Other: Editor and author; GlaxoSmithKline: Equity Ownership; Johnson&Johnson: Equity Ownership.

Immortalization and Characterization of Rat Lingual Keratinocytes in a High-Calcium and Feeder-Free Culture System Using ROCK Inhibitor Y-27632.

Cultured keratinocytes are desirable models for biological and medical studies. However, primary keratinocytes are difficult to maintain, and there has been little research on lingual keratinocyte culture. Here, we investigated the effect of Y-27632, a Rho kinase (ROCK) inhibitor, on the immortalization and characterization of cultured rat lingual keratinocyte (RLKs). Three Y-27632–supplemented media were screened for the cultivation of RLKs isolated from Sprague–Dawley rats. Phalloidin staining and TUNEL assay were applied to visualize cytoskeleton dynamics and cell apoptosis following Y-27632 removal. Label-free proteomics, RT-PCR, calcium imaging, and cytogenetic studies were conducted to characterize the cultured cells. Results showed that RLKs could be conditionally immortalized in a high-calcium medium in the absence of feeder cells, although they did not exhibit normal karyotypes. The removal of Y-27632 from the culture medium led to reversible cytoskeletal reorganization and nuclear enlargement without triggering apoptosis, and a total of 239 differentially expressed proteins were identified by proteomic analysis. Notably, RLKs derived from the non-taste epithelium expressed some molecular markers characteristic of taste bud cells, yet calcium imaging revealed that they rarely responded to tastants. Collectively, we established a high-calcium and feeder-free culture method for the long-term maintenance of RLKs. Our results shed some new light on the immortalization and differentiation of lingual keratinocytes.

Simplification of culture conditions and feeder-free expansion of bovine embryonic stem cells

Bovine embryonic stem cells (bESCs) extend the lifespan of the transient pluripotent bovine inner cell mass in vitro. After years of research, derivation of stable bESCs was only recently reported. Although successful, bESC culture relies on complex culture conditions that require a custom-made base medium and mouse embryonic fibroblasts (MEF) feeders, limiting the widespread use of bESCs. We report here simplified bESC culture conditions based on replacing custom base medium with a commercially available alternative and eliminating the need for MEF feeders by using a chemically-defined substrate. bESC lines were cultured and derived using a base medium consisting of N2B27 supplements and 1% BSA (NBFR-bESCs). Newly derived bESC lines were easy to establish, simple to propagate and stable after long-term culture. These cells expressed pluripotency markers and actively proliferated for more than 35 passages while maintaining normal karyotype and the ability to differentiate into derivatives of all three germ lineages in embryoid bodies and teratomas. In addition, NBFR-bESCs grew for multiple passages in a feeder-free culture system based on vitronectin and Activin A medium supplementation while maintaining pluripotency. Simplified conditions will facilitate the use of bESCs for gene editing applications and pluripotency and lineage commitment studies.

Canine induced pluripotent stem cell maintenance under feeder-free and chemically-defined conditions.

Canine induced pluripotent stem cells (ciPSCs) provide a platform for regenerative veterinary medicine, disease modeling, and drug discovery. However, in the conventional method, ciPSCs are maintained using chemically-undefined media containing unknown animal components under on-murine embryonic fibroblast feeder conditions, which were reported to modify cell surface of iPSCs and increases the risk of immune rejection when the cells are transplanted into patients. Moreover, in the conventional method, ciPSCs are mechanically passaged, which requires much time and effort. Therefore, the large-scale expansion of ciPSCs is difficult, which should be resolved for using ciPSCs in clinical application and research. Here, it was shown that StemFit® AK02N and iMatrix-511 could maintain the pluripotency of ciPSCs using conventional culture method. Furthermore, it was demonstrated that the feeder-free and chemically-defined ciPSC culture systems using StemFit® AK02N and iMatrix-511 could stably maintain and allow the easy expansion of ciPSCs generated using N2B27 and StemFit® AK02N, without causing karyotype abnormalities. ciPSCs expressed several pluripotency markers and formed teratomas, including cells derived from three germ layers.

Serum- and feeder-free culture expansion of human peripheral blood NK cells

Abstract Natural killer (NK) cells are critical effectors of innate immunity that secrete proinflammatory cytokines and kill tumor cells and virus-infected cells. The ability to expand human NK cells in culture provides a ready source of cells for disease modeling, development of immunotherapies, and basic research. We have developed a culture system that supports the expansion of primary NK cells in the absence of feeder cells and serum. NK cells were enriched from peripheral blood using EasySep™ negative selection and cultured in serum-free medium with interleukin-2 in plates coated with a NK cell ‘activation coating matrix’ for 14 days. Cells were passaged with medium changes on days 7 and 11, and were harvested on day 14 for assessment or functional characterization. The average frequency of CD56+CD3− NK cells was 92% (range 80 – 97%, n=16) with an average expansion of 121-fold (range 10 – 274). On average 79% (48–92%) of expanded NK cells expressed CD16. The ability of expanded NK cells to produce interferon-γ (IFN-γ) and to degranulate were tested after stimulation with phorbol 12-myristate 13-acetate (PMA) + ionomycin or co-culture with K562 cells. As detected by intracellular flow cytometry, the average frequency of IFN-γ+ NK cells was 56% (range 41 – 63%, n = 4) and 40% (range 12 – 55%) when stimulated by PMA/ionomycin or K562 cells, respectively. Similarly, the average frequency of degranulated NK cells as detected by surface expression of CD107a, a lysosomal-associated membrane protein, was 69% (range 35 – 84%, n = 4) and 53% (range 18 – 75%), respectively. These results show that NK cells can be expanded and stimulated under serum- and feeder-free conditions to generate large numbers of functional NK cells for basic and translational research.

Successful cryopreservation and regeneration of a partridge colored Hungarian native chicken breed using primordial germ cells

Primordial germ cells (PGCs) are the precursors of germline cells that generate sperm and ova in adults. Thus, they are promising tools for gene editing and genetic preservation, especially in avian species. In this study, we established stable male and female PGC lines from 6Hungarian indigenous chicken breeds with derivation rates ranging from 37.5 to 50 percent. We characterized the PGCs for expression of the germ cell-specific markers during prolonged culture in vitro. An in vivo colonization test was performed on PGCs from four Hungarian chicken breeds and the colonization rates were between 76 and 100%. Cryopreserved PGCs of the donor breed (Partridge color Hungarian) were injected into Black Transylvanian Naked Neck host embryos to form chimeric progeny that, after backcrossing, would permit reconstitution of the donor breed. For 24 presumptive chimeras 13 were male and 11 were female. In the course of backcrossing, 340 chicks were hatched and 17 of them (5%) were pure Partridge colored. Based on the backcrossing 1 hen and 3 roosters of the 24 presumptive chimeras (16.6%) have proven to be germline chimeras. Therefore, it was proven that the original breed can be recovered from primordial germ cells which are stored in the gene bank. To our knowledge, our study is a first that applied feeder free culturing conditions for both male and female cell lines successfully and used multiple indigenous chicken breeds to create a gene bank representing a region (Carpathian Basin).

Establishment of bovine expanded potential stem cells

Embryonic stem cells (ESCs) and induced pluripotent stem cells have the potential to differentiate to all cell types of an adult individual and are useful for studying development and for translational research. However, extrapolation of mouse and human ESC knowledge to deriving stable ESC lines of domestic ungulates and large livestock species has been challenging. In contrast to ESCs that are usually established from the blastocyst, mouse expanded potential stem cells (EPSCs) are derived from four-cell and eight-cell embryos. We have recently used the EPSC approach and established stem cells from porcine and human preimplantation embryos. EPSCs are molecularly similar across species and have broader developmental potential to generate embryonic and extraembryonic cell lineages. We further explore the EPSC technology for mammalian species refractory to the standard ESC approaches and report here the successful establishment of bovine EPSCs (bEPSCs) from preimplantation embryos of both wild-type and somatic cell nuclear transfer. bEPSCs express high levels of pluripotency genes, propagate robustly in feeder-free culture, and are genetically stable in long-term culture. bEPSCs have enriched transcriptomic features of early preimplantation embryos and differentiate in vitro to cells of the three somatic germ layers and, in chimeras, contribute to both the embryonic (fetal) and extraembryonic cell lineages. Importantly, precise gene editing is efficiently achieved in bEPSCs, and genetically modified bEPSCs can be used as donors in somatic cell nuclear transfer. bEPSCs therefore hold the potential to substantially advance biotechnology and agriculture.

A Non-Toxic Concentration of Telomerase Inhibitor BIBR1532 Fails to Reduce TERT Expression in a Feeder-Free Induced Pluripotent Stem Cell Model of Human Motor Neurogenesis.

Several studies have shown that human induced pluripotent stem cell (iPSC)-derivatives are essentially fetal in terms of their maturational status. Inducing ageing in iPSC-motor neuron (MN) models of amyotrophic lateral sclerosis (ALS) has the potential to capture pathology with higher fidelity and consequently improve translational success. We show here that the telomerase inhibitor BIBR1532, hypothesised to recapitulate the telomere attrition hallmark of ageing in iPSC-MNs, was in fact cytotoxic to feeder-free iPSCs when used at doses previously shown to be effective in iPSCs grown on a layer of mouse embryonic fibroblasts. Toxicity in feeder-free cultures was not rescued by co-treatment with Rho Kinase (ROCK) inhibitor (Y-27632). Moreover, the highest concentration of BIBR1532 compatible with continued iPSC culture proved insufficient to induce detectable telomerase inhibition. Our data suggest that direct toxicity by BIBR1532 is the most likely cause of iPSC death observed, and that culture methods may influence enhanced toxicity. Therefore, recapitulation of ageing hallmarks in iPSC-MNs, which might reveal novel and relevant human disease targets in ALS, is not achievable in feeder-free culture through the use of this small molecule telomerase inhibitor.

A non-invasive method to generate induced pluripotent stem cells from primate urine

Comparing the molecular and cellular properties among primates is crucial to better understand human evolution and biology. However, it is difficult or ethically impossible to collect matched tissues from many primates, especially during development. An alternative is to model different cell types and their development using induced pluripotent stem cells (iPSCs). These can be generated from many tissue sources, but non-invasive sampling would decisively broaden the spectrum of non-human primates that can be investigated. Here, we report the generation of primate iPSCs from urine samples. We first validate and optimize the procedure using human urine samples and show that suspension- Sendai Virus transduction of reprogramming factors into urinary cells efficiently generates integration-free iPSCs, which maintain their pluripotency under feeder-free culture conditions. We demonstrate that this method is also applicable to gorilla and orangutan urinary cells isolated from a non-sterile zoo floor. We characterize the urinary cells, iPSCs and derived neural progenitor cells using karyotyping, immunohistochemistry, differentiation assays and RNA-sequencing. We show that the urine-derived human iPSCs are indistinguishable from well characterized PBMC-derived human iPSCs and that the gorilla and orangutan iPSCs are well comparable to the human iPSCs. In summary, this study introduces a novel and efficient approach to non-invasively generate iPSCs from primate urine. This will extend the zoo of species available for a comparative approach to molecular and cellular phenotypes.

Generation of region-specific and high-purity neurons from human feeder-free iPSCs

Human induced pluripotent stem cells (iPSCs) have great potential to elucidate the molecular pathogenesis of neurological/psychiatric diseases. In particular, neurological/psychiatric diseases often display brain region-specific symptoms, and the technology for generating region-specific neural cells from iPSCs has been established for detailed modeling of neurological/psychiatric disease phenotypes in vitro. On the other hand, recent advances in culturing human iPSCs without feeder cells have enabled highly efficient and reproducible neural induction. However, conventional regional control technologies have mainly been developed based on on-feeder iPSCs, and these methods are difficult to apply to feeder-free (ff) iPSC cultures. In this study, we established a novel culture system to generate region-specific neural cells from human ff-iPSCs. This system is the best optimized approach for feeder-free iPSC culture and generates specific neuronal subtypes with high purity and functionality, including forebrain cortical neurons, forebrain interneurons, midbrain dopaminergic neurons, and spinal motor neurons. In addition, the temporal patterning of cortical neuron layer specification in the forebrain was reproduced in our culture system, which enables the generation of layer-specific cortical neurons. Neuronal activity was demonstrated in the present culture system by using multiple electrode array and calcium imaging. Collectively, our ff-iPSC-based culture system would provide a desirable platform for modeling various types of neurological/psychiatric disease phenotypes.

A clinically applicable and scalable method to regenerate T-cells from iPSCs for off-the-shelf T-cell immunotherapy

Clinical successes demonstrated by chimeric antigen receptor T-cell immunotherapy have facilitated further development of T-cell immunotherapy against wide variety of diseases. One approach is the development of “off-the-shelf” T-cell sources. Technologies to generate T-cells from pluripotent stem cells (PSCs) may offer platforms to produce “off-the-shelf” and synthetic allogeneic T-cells. However, low differentiation efficiency and poor scalability of current methods may compromise their utilities. Here we show improved differentiation efficiency of T-cells from induced PSCs (iPSCs) derived from an antigen-specific cytotoxic T-cell clone, or from T-cell receptor (TCR)-transduced iPSCs, as starting materials. We additionally describe feeder-free differentiation culture systems that span from iPSC maintenance to T-cell proliferation phases, enabling large-scale regenerated T-cell production. Moreover, simultaneous addition of SDF1α and a p38 inhibitor during T-cell differentiation enhances T-cell commitment. The regenerated T-cells show TCR-dependent functions in vitro and are capable of in vivo anti-tumor activity. This system provides a platform to generate a large number of regenerated T-cells for clinical application and investigate human T-cell differentiation and biology.

Feeder-Free Human Embryonic Stem Cell Culture Under Defined Culture Conditions.

Human embryonic stem (ES) cell culture has developed over the years allowing the subtle procedures that are easy to manipulate. Feeder-free ES cell culture is an important milestone for human pluripotent stem cell research which eliminates the feeder cells. Various matrices and medium formulations have been generated for feeder-independent culture. Here we described an mTeSR™1 based feeder-independent human ES cell culture on Matrigel® matrix. Culture, freeze/thaw, passaging and initiation of differentiation in suspension culture were described.

Episomal reprogramming of Duchenne muscular dystrophy patients derived CD3+ T cells towards induced pluripotent stem cells.

Objective:To derive Duchenne muscular dystrophy patient specific induced pluripotent stem cells (iPSCs) from CD3+T cells of DMD patients using episomal reprogramming and characterization of these DMD-iPSCs using immunofluorescence to confirm their pluripotent state.Methods:DMD patients were selected based upon their clinical history and examination. Peripheral blood mononuclear cells were isolated from peripheral blood of DMD patients (n=3) by density gradient centrifugation and were used to generate DMD patient specific T cells (DMD-T cells) using rhIL-2, plate bound anti CD3 antibody and T cell specific media along with specific culture conditions that promote T cell expansion. CD3+ T cells were characterized by flow cytometry and reprogrammed using episomal plasmid to generate DMD-iPSCs. These DMD-iPSCs were characterized using immunofluorescence. The study was carried out at Dow Research Institute of Biotechnology and Biomedical Sciences during August 2017- July 2018 for a period of approximately 12 months.Results:The peripheral blood mononuclear cells (PBMNC) derived T cells appeared as suspended cell clumps morphologically were positive for the expression of CD3 and negative for CD31. The DMD patient specific iPSCs appeared as round, compact and flat colonies with well-defined edges morphologically and were positive for the expression of pluripotency markers OCT4, SSEA-4 and TRA-1-81 on immunofluorescence.Conclusion:CD3+ T cell derived DMD-iPSCs were obtained under feeder free and xeno-free culture conditions using episomal reprogramming.

Feeder-Free Human Induced Pluripotent Stem Cell Culture Using a DNA Aptamer-Based Mimic of Basic Fibroblast Growth Factor.

Cell culture media are often supplemented with recombinant growth factors and cytokines to reproduce biological conditions in vitro. Basic fibroblast growth factor (bFGF) has been widely used to support the pluripotency and self-renewal activity of human induced pluripotent stem cells (hiPSCs). We had previously developed a synthetic surrogate for bFGF on the basis of a DNA aptamer that binds to one of the FGF receptors. Since DNA aptamers have advantages over recombinant proteins in terms of thermal stability and production cost, replacing recombinant growth factors in cell culture media with DNA aptamers would be of great interest. Herein, we describe our protocol for feeder-free hiPSC culture using a DNA aptamer-based mimic of bFGF.

Feeder-Free Cell Culture of Labial Oral Mucosal Epithelium for Tissue-Engineering and Regenerative Medicine

Background.The cultured cheek mucosa epithelium (buccal epithelium, BE) is used for autologous transplants generation and tissue engineering. An alternative source of cells for these purposes may be the lip mucosa, covered, like BE, with non-keratinized stratified squamous epithelium, but with some histological distinctions.Aims to characterize the human lip mucosa as a promising source of epithelial cells for autologous transplantation and tissue engineering.Methods.Scrapings of the lip, cheek, and gum mucosa from five healthy volunteers were analyzed by cytofluorimetry to determine the level of desquamation and cytokeratin (CK) 10 and 13 expression. The lip mucosa of two patients was characterized using routine histological staining and fluorescence immunohistochemistry for CK 3, 4, 10, 13, and p63 marker. 35 samples of full-thickness strips of the patients lip mucosa were used to set the explant (n=18) and enzymatic (n=17) techniques for expansion epithelium. Culture systems with 1.05 and 0.06mM Calcium contained 5% fetal bovine serum, 5 g/ml human insulin, 5 g/ml hydrocortisone, 10 ng/ml human epidermal growth factor. Stable cultures were stained for p63, vimentin, zonula occludens-1 (ZO-1), and CK10. Software tools determined levels of their expression.Results.The number of cells in the lip and gum samples was significantly lower than from the cheek. The median number of CK13 positive cells was significantly different for the gum (6.4%) and cheek (64.8%, p=0.0089). Significant differences for CK10 positive cells were not observed. The epithelium of the lip mucosa was 72.13.6 m thick, relatively flat, and without keratinization sites. Samples were positively stained for CK 4 and 13, in the absence of expression of CK 3 and 10. The primary culture of epithelial cells obtained by explant technique was significantly more effective (p=0.001) in comparison with the enzymatic method. Stable cultures had a cobble-stone morphology in both culture systems. The levels of vimentin and p63 expression in both culture systems was not significantly differ. ZO-1 expression was 3.6-fold higher for 1.05-mMCa++medium (p=0.0006).Conclusions.Epithelium cell culture from the lip mucosa can be obtained by culturing explants without a feeder layer. Quality control steps have been developed for cultured cells and biopsy site.