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Temporal manipulation of the in vitro environment and growth factors can direct differentiation of human pluripotent stem cells into organoids - aggregates with multiple tissue-specific cell types and three-dimensional structure mimicking native organs. A mechanistic understanding of early organoid formation is essential for improving the robustness of these methods,which is necessary prior to use in drug development and regenerative medicine. We investigated intestinal organoid emergence,focusing on measurable parameters of hindgut spheroids,the intermediate step between definitive endoderm and mature organoids. We found that 13{\%} of spheroids were pre-organoids that matured into intestinal organoids. Spheroids varied by several structural parameters: cell number,diameter and morphology. Hypothesizing that diameter and the morphological feature of an inner mass were key parameters for spheroid maturation,we sorted spheroids using an automated micropipette aspiration and release system and monitored the cultures for organoid formation. We discovered that populations of spheroids with a diameter greater than 75 $\mu$m and an inner mass are enriched 1.5- and 3.8-fold for pre-organoids,respectively,thus providing rational guidelines towards establishing a robust protocol for high quality intestinal organoids. View Publication

Genetic modification of cell lines and primary cells is an expensive and cumbersome approach,often involving the use of viral vectors. Electroporation using square-wave generating devices,like Lonza's Nucleofector,is a widely used option,but the costs associated with the acquisition of electroporation kits and the transient transgene expression might hamper the utility of this methodology. In the present work,we show that our in-house developed buffers,termed Chicabuffers,can be efficiently used to electroporate cell lines and primary cells from murine and human origin. Using the Nucleofector II device,we electroporated 14 different cell lines and also primary cells,like mesenchymal stem cells and cord blood CD34+,providing optimized protocols for each of them. Moreover,when combined with sleeping beauty-based transposon system,long-term transgene expression could be achieved in all types of cells tested. Transgene expression was stable and did not interfere with CD34+ differentiation to committed progenitors. We also show that these buffers can be used in CRISPR-mediated editing of PDCD1 gene locus in 293T and human peripheral blood mononuclear cells. The optimized protocols reported in this study provide a suitable and cost-effective platform for the genetic modification of cells,facilitating the widespread adoption of this technology. View Publication

Age-related macular degeneration (AMD) affects the retinal pigment epithelium (RPE),a cell monolayer essential for photoreceptor survival,and is the leading cause of vision loss in the elderly. There are no disease-altering therapies for dry AMD,which is characterized by accumulation of subretinal drusen deposits and complement-driven inflammation. We report the derivation of human-induced pluripotent stem cells (hiPSCs) from patients with diagnosed AMD,including two donors with the rare ARMS2/HTRA1 homozygous genotype. The hiPSC-derived RPE cells produce several AMD/drusen-related proteins,and those from the AMD donors show significantly increased complement and inflammatory factors,which are most exaggerated in the ARMS2/HTRA1 lines. Using a panel of AMD biomarkers and candidate drug screening,combined with transcriptome analysis,we discover that nicotinamide (NAM) ameliorated disease-related phenotypes by inhibiting drusen proteins and inflammatory and complement factors while upregulating nucleosome,ribosome,and chromatin-modifying genes. Thus,targeting NAM-regulated pathways is a promising avenue for developing therapeutics to combat AMD. View Publication

The cornea is the transparent outermost surface of the eye,consisting of a stratified epithelium,a collagenous stroma and an innermost single-cell layered endothelium and providing 2/3 of the refractive power of the eye. Multiple diseases of the cornea arise from genetic defects where the ultimate phenotype can be influenced by cross talk between the cell types and the extracellular matrix. Cell culture modeling of diseases can benefit from cornea organoids that include multiple corneal cell types and extracellular matrices. Here we present human iPS cell-derived organoids through sequential rounds of differentiation programs. These organoids share features of the developing cornea,harboring three distinct cell types with expression of key epithelial,stromal and endothelial cell markers. Cornea organoid cultures provide a powerful 3D model system for investigating corneal developmental processes and their disruptions in diseased conditions. View Publication

We have recently demonstrated the effectiveness of an influenza A virus (IAV) subunit vaccine based on biodegradable polyanhydride nanoparticles delivery in mice. In the present study,we evaluated the efficacy of ∼200nm polyanhydride nanoparticles encapsulating inactivated swine influenza A virus (SwIAV) as a vaccine to induce protective immunity against a heterologous IAV challenge in pigs. Nursery pigs were vaccinated intranasally twice with inactivated SwIAV H1N2 (KAg) or polyanhydride nanoparticle-encapsulated KAg (KAg nanovaccine),and efficacy was evaluated against a heterologous zoonotic virulent SwIAV H1N1 challenge. Pigs were monitored for fever daily. Local and systemic antibody responses,antigen-specific proliferation of peripheral blood mononuclear cells,gross and microscopic lung lesions,and virus load in the respiratory tract were compared among the groups of animals. Our pre-challenge results indicated that KAg nanovaccine induced virus-specific lymphocyte proliferation and increased the frequency of CD4+CD8$\alpha$$\alpha$+ T helper and CD8+ cytotoxic T cells in peripheral blood mononuclear cells. KAg nanovaccine-immunized pigs were protected from fever following SwIAV challenge. In addition,pigs immunized with the KAg nanovaccine presented with lower viral antigens in lung sections and had 6 to 8-fold reduction in nasal shedding of SwIAV four days post-challenge compared to control animals. Immunologically,increased IFN-$\gamma$ secreting T lymphocyte populations against both the vaccine and challenge viruses were detected in KAg nanovaccine-immunized pigs compared to the animals immunized with KAg alone. However,in the KAg nanovaccine-immunized pigs,hemagglutination inhibition,IgG and IgA antibody responses,and virus neutralization titers were comparable to that in the animals immunized with KAg alone. Overall,our data indicated that intranasal delivery of polyanhydride-based SwIAV nanovaccine augmented antigen-specific cellular immune response in pigs,with promise to induce cross-protective immunity. View Publication

Haematopoietic stem cell (HSC) gene therapy has demonstrated potential to treat many diseases. However,current state of the art requires sophisticated ex vivo gene transfer in a dedicated Good Manufacturing Practices facility,limiting availability. An automated process would improve the availability and standardized manufacture of HSC gene therapy. Here,we develop a novel program for semi-automated cell isolation and culture equipment to permit complete benchtop generation of gene-modified CD34+ blood cell products for transplantation. These cell products meet current manufacturing quality standards for both mobilized leukapheresis and bone marrow,and reconstitute human haematopoiesis in immunocompromised mice. Importantly,nonhuman primate autologous gene-modified CD34+ cell products are capable of stable,polyclonal multilineage reconstitution with follow-up of more than 1 year. These data demonstrate proof of concept for point-of-care delivery of HSC gene therapy. Given the many target diseases for gene therapy,there is enormous potential for this approach to treat patients on a global scale. View Publication

Acute myeloid leukemia (AML) is a heterogeneous group of aggressive bone marrow cancers arising from transformed hematopoietic stem and progenitor cells (HSPC). Therapy-related AML and MDS (t-AML/MDS) comprise a subset of AML cases occurring after exposure to alkylating chemotherapy and/or radiation and are associated with a very poor prognosis. Less is known about the pathogenesis and disease-initiating/leukemia stem cell (LSC) subpopulations of t-AML/MDS compared to their de novo counterparts. Here,we report the development of mouse models of t-AML/MDS. First,we modeled alkylator-induced t-AML/MDS by exposing wild type adult mice to N-ethyl-N-nitrosurea (ENU),resulting in several models of AML and MDS that have clinical and pathologic characteristics consistent with human t-AML/MDS including cytopenia,myelodysplasia,and shortened overall survival. These models were limited by their inability to transplant clinically aggressive disease. Second,we established three patient-derived xenograft models of human t-AML. These models led to rapidly fatal disease in recipient immunodeficient xenografted mice. LSC activity was identified in multiple HSPC subpopulations suggesting there is no canonical LSC immunophenotype in human t-AML. Overall,we report several new t-AML/MDS mouse models that could potentially be used to further define disease pathogenesis and test novel therapeutics. View Publication

Gene therapy with genetically modified human CD34(+) hematopoietic stem and progenitor cells (HSPCs) may be safer using targeted integration (TI) of transgenes into a genomic 'safe harbor' site rather than random viral integration. We demonstrate that temporally optimized delivery of zinc finger nuclease mRNA via electroporation and adeno-associated virus (AAV) 6 delivery of donor constructs in human HSPCs approaches clinically relevant levels of TI into the AAVS1 safe harbor locus. Up to 58{\%} Venus(+) HSPCs with 6-16{\%} human cell marking were observed following engraftment into mice. In HSPCs from patients with X-linked chronic granulomatous disease (X-CGD),caused by mutations in the gp91phox subunit of the NADPH oxidase,TI of a gp91phox transgene into AAVS1 resulted in ∼15{\%} gp91phox expression and increased NADPH oxidase activity in ex vivo-derived neutrophils. In mice transplanted with corrected HSPCs,4-11{\%} of human cells in the bone marrow expressed gp91phox. This method for TI into AAVS1 may be broadly applicable to correction of other monogenic diseases. View Publication

Yaffe and colleagues discuss the issues surrounding the authentication and quality of induced pluripotent stem cells.

This protocol describes a strategy for the generation of 3D prostate organoid cultures from healthy mouse and human prostate cells (either bulk or FACS-sorted single luminal and basal cells),metastatic prostate cancer lesions and circulating tumor cells. Organoids derived from healthy material contain the differentiated luminal and basal cell types,whereas organoids derived from prostate cancer tissue mimic the histology of the tumor. We explain how to establish these cultures in the fully defined serum-free conditioned medium that is required to sustain organoid growth. Starting with the plating of digested tissue material,full-grown organoids can usually be obtained in ∼2 weeks. The culture protocol we describe here is currently the only one that allows the growth of both the luminal and basal prostatic epithelial lineages,as well as the growth of advanced prostate cancers. Organoids established using this protocol can be used to study many different aspects of prostate biology,including homeostasis,tumorigenesis and drug discovery. View Publication