Scientific Resources

Background: Local ischemia is the main pathological performance in osteonecrosis of the femoral head (ONFH). There is currently no effective therapy to promote angiogenesis in the femoral head. Recent studies revealed that exosomes secreted by induced pluripotent stem cell-derived mesenchymal stem cells (iPS-MSC-Exos) have great therapeutic potential in ischemic tissues,but whether they could promote angiogenesis in ONFH has not been reported,and little is known regarding the underlying mechanism. Methods: iPS-MSC-Exos were intravenously injected to a steroid-induced rat osteonecrosis model. Samples of the femoral head were obtained 3 weeks after all the injections. The effects were assessed by measuring local angiogenesis and bone loss through histological and immunohistochemical (IHC) staining,micro-CT and three-dimensional microangiography. The effects of exosomes on endothelial cells were studied through evaluations of proliferation,migration and tube-forming analyses. The expression levels of angiogenic related PI3K/Akt signaling pathway of endothelial cells were evaluated following stimulation of iPS-MSC-Exos. The promoting effects of exosomes were re-evaluated following blockade of PI3K/Akt. Results: The in vivo study revealed that administration of iPS-MSC-Exos significantly prevented bone loss,and increased microvessel density in the femoral head compared with control group. We found that iPS-MSC-Exos significantly enhanced the proliferation,migration and tube-forming capacities of endothelial cells in vitro. iPS-MSC-Exos could activate PI3K/Akt signaling pathway in endothelial cells. Moreover,the promoting effects of iPS-MSC-Exos were abolished after blockade of PI3K/Akt on endothelial cells. Conclusions: Our findings suggest that transplantation of iPS-MSC-Exos exerts a preventative effect on ONFH by promoting local angiogenesis and preventing bone loss. The promoting effect might be attributed to activation of the PI3K/Akt signaling pathway on endothelial cells. The data provide the first evidence for the potential of iPS-MSC-Exos in treating ONFH. 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

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

Immunotherapy has increased overall survival of metastatic cancer patients,and cancer antigens are promising vaccine targets. To fulfill the promise,appropriate tailoring of the vaccine formulations to mount in vivo cytotoxic T cell (CTL) responses toward co-delivered cancer antigens is essential. Previous development of therapeutic cancer vaccines has largely been based on studies in mice,and the majority of these candidate vaccines failed to induce therapeutic responses in the subsequent human clinical trials. Given that antigen dose and vaccine volume in pigs are translatable to humans and the porcine immunome is closer related to the human counterpart,we here introduce pigs as a supplementary large animal model for human cancer vaccine development. IDO and RhoC,both important in human cancer development and progression,were used as vaccine targets and 12 pigs were immunized with overlapping 20mer peptides spanning the entire porcine IDO and RhoC sequences formulated in CTL-inducing adjuvants: CAF09,CASAC,Montanide ISA 51 VG,or PBS. Taking advantage of recombinant swine MHC class I molecules (SLAs),the peptide-SLA complex stability was measured for 198 IDO- or RhoC-derived 9-11mer peptides predicted to bind to SLA-1(*)04:01,-1(*)07:02,-2(*)04:01,-2(*)05:02,and/or -3(*)04:01. This identified 89 stable (t½ ≥ 0.5 h) peptide-SLA complexes. By IFN-$\gamma$ release in PBMC cultures we monitored the vaccine-induced peptide-specific CTL responses,and found responses to both IDO- and RhoC-derived peptides across all groups with no adjuvant being superior. These findings support the further use of pigs as a large animal model for vaccine development against human cancer. View Publication

The lack of in vitro prostate cancer models that recapitulate the diversity of human prostate cancer has hampered progress in understanding disease pathogenesis and therapy response. Using a 3D organoid system,we report success in long-term culture of prostate cancer from biopsy specimens and circulating tumor cells. The first seven fully characterized organoid lines recapitulate the molecular diversity of prostate cancer subtypes,including TMPRSS2-ERG fusion,SPOP mutation,SPINK1 overexpression,and CHD1 loss. Whole-exome sequencing shows a low mutational burden,consistent with genomics studies,but with mutations in FOXA1 and PIK3R1,as well as in DNA repair and chromatin modifier pathways that have been reported in advanced disease. Loss of p53 and RB tumor suppressor pathway function are the most common feature shared across the organoid lines. The methodology described here should enable the generation of a large repertoire of patient-derived prostate cancer lines amenable to genetic and pharmacologic studies. View Publication

Small-cell lung cancer (SCLC),an aggressive neuroendocrine tumor with early dissemination and dismal prognosis,accounts for 15-20{\%} of lung cancer cases and ∼200,000 deaths each year. Most cases are inoperable,and biopsies to investigate SCLC biology are rarely obtainable. Circulating tumor cells (CTCs),which are prevalent in SCLC,present a readily accessible 'liquid biopsy'. Here we show that CTCs from patients with either chemosensitive or chemorefractory SCLC are tumorigenic in immune-compromised mice,and the resultant CTC-derived explants (CDXs) mirror the donor patient's response to platinum and etoposide chemotherapy. Genomic analysis of isolated CTCs revealed considerable similarity to the corresponding CDX. Most marked differences were observed between CDXs from patients with different clinical outcomes. These data demonstrate that CTC molecular analysis via serial blood sampling could facilitate delivery of personalized medicine for SCLC. CDXs are readily passaged,and these unique mouse models provide tractable systems for therapy testing and understanding drug resistance mechanisms. View Publication

IMPORTANCE Although leukocyte telomere length is associated with mortality and many chronic diseases thought to be manifestations of age-related functional decline,it is not known whether it relates to acute disease in younger healthy populations. OBJECTIVE To determine whether shorter telomeres in leukocytes,especially CD8CD28- T cells,are associated with decreased resistance to upper respiratory infection and clinical illness in young to midlife adults. DESIGN,SETTING,AND PARTICIPANTS Between 2008 and 2011,telomere length was assessed in peripheral blood mononuclear cells (PBMCs) and T-cell subsets (CD4,CD8CD28+,CD8CD28-) from 152 healthy 18- to 55-year-old residents of Pittsburgh,Pennsylvania. Participants were subsequently quarantined (single rooms),administered nasal drops containing a common cold virus (rhinovirus 39),and monitored for 5 days for development of infection and clinical illness. MAIN OUTCOME MEASURES Infection (virus shedding or 4-fold increase in virus-specific antibody titer) and clinical illness (verified infection plus objective signs of illness). RESULTS Rates of infections and clinical illness were 69{\%} (n = 105) and 22{\%} (n = 33),respectively. Shorter telomeres were associated with greater odds of infection,independent of prechallenge virus-specific antibody,demographics,contraceptive use,season,and body mass index (PBMC: odds ratio [OR] per 1-SD decrease in telomere length,1.71 [95{\%} CI,1.08-2.72]; n = 128 [shortest tertile 77{\%} infected; middle,66{\%}; longest,57{\%}]; CD4: OR,1.76 [95{\%} CI,1.15-2.70]; n = 146 [shortest tertile 80{\%} infected; middle,71{\%}; longest,54{\%}]; CD8CD28+: OR,1.93 [95{\%} CI,1.21-3.09],n = 132 [shortest tertile 84{\%} infected; middle,64{\%}; longest,58{\%}]; CD8CD28-: OR,2.02 [95{\%} CI,1.29-3.16]; n = 144 [shortest tertile 77{\%} infected; middle,75{\%}; longest,50{\%}]). CD8CD28- was the only cell population in which shorter telomeres were associated with greater risk of clinical illness (OR,1.69 [95{\%} CI,1.01-2.84]; n = 144 [shortest tertile,26{\%}; middle,22{\%}; longest,13{\%}]). The association between CD8CD28- telomere length and infection increased with age (CD8CD28- telomere length × age interaction,b = 0.09 [95{\%} CI,0.02-0.16],P = .01,n = 144). CONCLUSION AND RELEVANCE In this preliminary study among a cohort of healthy 18- to 55-year-olds,shorter CD8CD28- T-cell telomere length was associated with increased risk for experimentally induced acute upper respiratory infection and clinical illness. View Publication

Characterization of pluripotent stem cells is required for the registration of stem cell lines and allows for an impartial and objective comparison of the results obtained when generating multiple lines. It is therefore crucial to establish specific,fast and reliable protocols to detect the hallmarks of pluripotency. Such protocols should include immunocytochemistry (takes 2 d),identification of the three germ layers in in vitro-derived embryoid bodies by immunocytochemistry (immunodetection takes 3 d) and detection of differentiation markers in in vivo-generated teratomas by immunohistochemistry (differentiation marker detection takes 4 d). Standardization of the immunodetection protocols used ensures minimum variations owing to the source,the animal species,the endogenous fluorescence or the inability to collect large amounts of cells,thereby yielding results as fast as possible without loss of quality. This protocol provides a description of all the immunodetection procedures necessary to characterize mouse and human stem cell lines in different circumstances.

During the progression of autoimmune (type 1) diabetes,T cells and macrophages infiltrate the pancreas,disrupt islet function,and destroy insulin-producing beta cells. B-lymphocytes,particularly innate like B-cell populations such as marginal zone B cells and B-1 cells,have been implicated in many autoimmune diseases,and non-obese diabetic (NOD) mice that lack B cells do not develop spontaneous autoimmune diabetes. Hence,inhibitors of B cell signaling pathways could be useful for limiting the autoimmune processes that contribute to type 1 diabetes. Signaling via phosphoinositide 3-kinase (PI3K) regulates many cellular processes. The p110$\delta$ isoform of PI3K is expressed primarily in cells of hematopoietic origin and the catalytic activity of p110$\delta$ is important for B cell migration,activation,proliferation,and antigen presentation. Because innate-like B cells are particularly sensitive to inhibition of p110$\delta$ activity,and p110$\delta$ inhibitors also suppress pro-inflammatory functions of other cell types that contribute to autoimmunity,we tested whether a p110$\delta$ inhibitor could delay the onset or reduce the incidence of autoimmune diabetes in NOD mice. We found that long-term preventative treatment of pre-diabetic NOD mice with IC87114,a highly selective small molecule inhibitor of p110$\delta$,reduced the infiltration of inflammatory cells into the pancreatic islets and,accordingly,delayed and reduced the loss of glucose homeostasis. Moreover in a therapeutic treatment mode,IC87114 treatment conferred prolonged protection from progression to overt diabetes in a number of animals. These findings suggest that PI3K$\delta$ inhibitors could be useful for managing type 1 diabetes. View Publication