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Although human induced pluripotent stem cells (hiPSCs) hold great potential for the study of human diseases affecting disparate cell types,they have been underutilized in seeking mechanistic insights into the pathogenesis of congenital craniofacial disorders. Craniofrontonasal syndrome (CFNS) is a rare X-linked disorder caused by mutations in EFNB1 and characterized by craniofacial,skeletal,and neurological anomalies. Heterozygous females are more severely affected than hemizygous males,a phenomenon termed cellular interference that involves mosaicism for EPHRIN-B1 function. Although the mechanistic basis for cellular interference in CFNS has been hypothesized to involve Eph/ephrin-mediated cell segregation,no direct evidence for this has been demonstrated. Here,by generating hiPSCs from CFNS patients,we demonstrate that mosaicism for EPHRIN-B1 expression induced by random X inactivation in heterozygous females results in robust cell segregation in human neuroepithelial cells,thus supplying experimental evidence that Eph/ephrin-mediated cell segregation is relevant to pathogenesis in human CFNS patients. View Publication

Huntington disease (HD) is a dominant neurodegenerative disorder caused by a CAG repeat expansion in HTT. Here we report correction of HD human induced pluripotent stem cells (hiPSCs) using a CRISPR-Cas9 and piggyBac transposon-based approach. We show that both HD and corrected isogenic hiPSCs can be differentiated into excitable,synaptically active forebrain neurons. We further demonstrate that phenotypic abnormalities in HD hiPSC-derived neural cells,including impaired neural rosette formation,increased susceptibility to growth factor withdrawal,and deficits in mitochondrial respiration,are rescued in isogenic controls. Importantly,using genome-wide expression analysis,we show that a number of apparent gene expression differences detected between HD and non-related healthy control lines are absent between HD and corrected lines,suggesting that these differences are likely related to genetic background rather than HD-specific effects. Our study demonstrates correction of HD hiPSCs and associated phenotypic abnormalities,and the importance of isogenic controls for disease modeling using hiPSCs. View Publication

BACKGROUND Neuroblastoma (NB),a tumor of the primitive neural crest,despite aggressive treatment portends a poor long-term survival for patients with advanced high stage NB. New treatment strategies are required. METHODS We investigated coordinated targeting of essential homeostatic regulatory factors involved in cancer progression,histone deacetylases (HDACs) and carbonic anhydrases (CAs). RESULTS We evaluated the antitumor potential of the HDAC inhibitor (HDACi),pyridylmethyl-N-4-[(2-aminophenyl)-carbamoyl]-benzyl-carbamate (MS-275) in combination with a pan CA inhibitor,acetazolamide (AZ) on NB SH-SY5Y,SK-N-SH and SK-N-BE(2) cells. The key observation was that the combination AZ + MS-275 significantly inhibited growth,induced cell cycle arrest and apoptosis,and reduced migration capacity of NB cell line SH-SY5Y. In addition,this combination significantly inhibited tumor growth in vivo,in a pre-clinical xenograft model. Evidence was obtained for a marked reduction in tumorigenicity and in the expression of mitotic,proliferative,HIF-1α and CAIX. NB xenografts of SH-SY5Y showed a significant increase in apoptosis. CONCLUSION MS-275 alone at nanomolar concentrations significantly reduced the putative cancer stem cell (CSC) fraction of NB cell lines,SH-SY5Y and SK-N-BE(2),in reference to NT2/D1,a teratocarcinoma cell line,exhibiting a strong stem cell like phenotype in vitro. Whereas stemness genes (OCT4,SOX2 and Nanog) were found to be significantly downregulated after MS-275 treatment,this was further enhanced by AZ co-treatment. The significant reduction in initial tumorigenicity and subsequent abrogation upon serial xenografting suggests potential elimination of the NB CSC fraction. The significant potentiation of MS-275 by AZ is a promising therapeutic approach and one amenable for administration to patients given their current clinical utility. View Publication

The ability to generate spiral ganglion neurons (SGNs) from stem cells is a necessary prerequisite for development of cell-replacement therapies for sensorineural hearing loss. We present a protocol that directs human embryonic stem cells (hESCs) toward a purified population of otic neuronal progenitors (ONPs) and SGN-like cells. Between 82% and 95% of these cells express SGN molecular markers,they preferentially extend neurites to the cochlear nucleus rather than nonauditory nuclei,and they generate action potentials. The protocol follows an in vitro stepwise recapitulation of developmental events inherent to normal differentiation of hESCs into SGNs,resulting in efficient sequential generation of nonneuronal ectoderm,preplacodal ectoderm,early prosensory ONPs,late ONPs,and cells with cellular and molecular characteristics of human SGNs. We thus describe the sequential signaling pathways that generate the early and later lineage species in the human SGN lineage,thereby better describing key developmental processes. The results indicate that our protocol generates cells that closely replicate the phenotypic characteristics of human SGNs,advancing the process of guiding hESCs to states serving inner-ear cell-replacement therapies and possible next-generation hybrid auditory prostheses. textcopyright Stem Cells Translational Medicine 2017;6:923-936. View Publication

Insulin-like growth factor (IGF) is involved in regulating many processes during neural development,and IGF binding protein-4 (IGFBP4) functions as a modulator of IGF actions or in an IGF-independent manner (e.g.,via inhibiting Wnt/β-catenin signaling). In the present study,neural progenitor cells (NPCs) were isolated from the forebrain of newborn mice to investigate effects of IGFBP4 on the proliferation and differentiation of NPCs. The proliferation of NPCs was evaluated using Cell Counting Kit-8 (CCK-8) after treatment with or without IGFBP4 as well as blockers of IGF-IR and β-catenin. Phosphorylation levels of Akt,Erk1,2 and p38 were analyzed by Western blotting. The differentiation of NPCs was evaluated using immunofluorescence and Western blotting. It was shown that exogenous IGFBP4 significantly inhibited the proliferation of NPCs and it did not induce a more pronounced inhibition of cell proliferation after blockade of IGF-IR but it did after antagonism of β-catenin. Akt phosphorylation was significantly decreased and phosphorylation levels of Erk1,2 and p38 were not significantly changed in IGFBP4-treated NPCs. Excessive IGFBP4 significantly promoted NPCs to differentiate into astrocytes and neurons. These data suggested that exogenous IGFBP4 inhibits proliferation and promotes differentiation of neural progenitor cells mainly through IGF-IR signaling pathway. View Publication

BACKGROUND Neonatal hypoxia-ischemia induces massive brain damage during the perinatal period,resulting in long-term consequences to central nervous system structural and functional maturation. Although neural progenitor cells (NPCs) migrate through the parenchyma and home in to injury sites in the rodent brain,the molecular mechanisms are unknown. We examined the role of chemokines in mediating NPC migration after neonatal hypoxic-ischemic brain injury. METHODS Nine-day-old mice were exposed to a 120-minute hypoxia following unilateral carotid occlusion. Chemokine levels were quantified in mouse brain extract. Migration and proliferation assays were performed using embryonic and infant mouse NPCs. RESULTS The neonatal hypoxic-ischemic brain injury resulted in an ipsilateral lesion,which was extended to the cortical and striatal areas. NPCs migrated toward an injured area,where a marked increase of CC chemokines was detected. In vitro studies showed that incubation of NPCs with recombinant mouse CCL11 promoted migration and proliferation. These effects were partly inhibited by a CCR3 antagonist,SB297006. CONCLUSIONS Our data implicate an important effect of CCL11 for mouse NPCs. The effective activation of NPCs may offer a promising strategy for neuroregeneration in neonatal hypoxic-ischemic brain injury. View Publication

Engineered neural stem cells (NSCs) are a promising approach to treating glioblastoma (GBM). The ideal NSC drug carrier for clinical use should be easily isolated and autologous to avoid immune rejection. We transdifferentiated (TD) human fibroblasts into tumor-homing early-stage induced NSCs (h-iNSC(TE)),engineered them to express optical reporters and different therapeutic gene products,and assessed the tumor-homing migration and therapeutic efficacy of cytotoxic h-iNSC(TE) in patient-derived GBM models of surgical and nonsurgical disease. Molecular and functional analysis revealed that our single-factor SOX2 TD strategy converted human skin fibroblasts into h-iNSC(TE) that were nestin(+) and expressed pathways associated with tumor-homing migration in 4 days. Time-lapse motion analysis showed that h-iNSC(TE) rapidly migrated to human GBM cells and penetrated human GBM spheroids,a process inhibited by blockade of CXCR4. Serial imaging showed that h-iNSC(TE) delivery of the proapoptotic agent tumor necrosis factor-α-related apoptosis-inducing ligand (TRAIL) reduced the size of solid human GBM xenografts 250-fold in 3 weeks and prolonged median survival from 22 to 49 days. Additionally,h-iNSC(TE) thymidine kinase/ganciclovir enzyme/prodrug therapy (h-iNSC(TE)-TK) reduced the size of patient-derived GBM xenografts 20-fold and extended survival from 32 to 62 days. Mimicking clinical NSC therapy,h-iNSC(TE)-TK therapy delivered into the postoperative surgical resection cavity delayed the regrowth of residual GBMs threefold and prolonged survival from 46 to 60 days. These results suggest that TD of human skin into h-iNSC(TE) is a platform for creating tumor-homing cytotoxic cell therapies for cancer,where the potential to avoid carrier rejection could maximize treatment durability in human trials. View Publication

L-2-hydroxyglutarate aciduria (L-2-HGA) is an autosomal recessive neurometabolic disorder caused by a mutation in the L-2-hydroxyglutarate dehydrogenase ( L2HGDH ) gene. In this study,we generated L2hgdh knockout (KO) mice and observed a robust increase of 2-hydroxyglutarate (L-2-HG) levels in multiple tissues. The highest levels of L-2-HG were observed in the brain and testis with a corresponding increase in histone methylation in these tissues. L2hgdh KO mice exhibit white matter abnormalities,extensive gliosis,microglia-mediated neuroinflammation,and an expansion of oligodendrocyte progenitor cells (OPCs). Moreover,L2hgdh deficiency leads to impaired adult hippocampal neurogenesis and late-onset neurodegeneration in mouse brains. Our data provide in vivo evidence that L2hgdh mutation leads to L-2-HG accumulation,leukoencephalopathy,and neurodegeneration in mice,thus offering new insights into the pathophysiology of L-2-HGA in humans. View Publication

The recent Zika virus (ZIKV) epidemic is associated with microcephaly in newborns. Although the connection between ZIKV and neurodevelopmental defects is widely recognized,the underlying mechanisms are poorly understood. Here we show that two recently isolated strains of ZIKV,an American strain from an infected fetal brain (FB-GWUH-2016) and a closely-related Asian strain (H/PF/2013),productively infect human iPSC-derived brain organoids. Both of these strains readily target to and replicate in proliferating ventricular zone (VZ) apical progenitors. The main phenotypic effect was premature differentiation of neural progenitors associated with centrosome perturbation,even during early stages of infection,leading to progenitor depletion,disruption of the VZ,impaired neurogenesis,and cortical thinning. The infection pattern and cellular outcome differ from those seen with the extensively passaged ZIKV strain MR766. The structural changes we see after infection with these more recently isolated viral strains closely resemble those seen in ZIKV-associated microcephaly. View Publication

OBJECTIVE In this work we set to develop and to validate a new in vivo frameless orthotopic Diffuse Intrinsic Pontine Glioma (DIPG) model based in the implantation of a guide-screw system. METHODS It consisted of a guide-screw also called bolt,a Hamilton syringe with a 26-gauge needle and an insulin-like 15-gauge needle. The guide screw is 2.6 mm in length and harbors a 0.5 mm central hole which accepts the needle of the Hamilton syringe avoiding a theoretical displacement during insertion. The guide-screw is fixed on the mouse skull according to the coordinates: 1mm right to and 0.8 mm posterior to lambda. To reach the pons the Hamilton syringe is adjusted to a 6.5 mm depth using a cuff that serves as a stopper. This system allows delivering not only cells but also any kind of intratumoral chemotherapy,antibodies or gene/viral therapies. RESULTS The guide-screw was successfully implanted in 10 immunodeficient mice and the animals were inoculated with DIPG human cell lines during the same anesthetic period. All the mice developed severe neurologic symptoms and had a median overall survival of 95 days ranging the time of death from 81 to 116 days. Histopathological analysis confirmed tumor into the pons in all animals confirming the validity of this model. CONCLUSION Here we presented a reproducible and frameless DIPG model that allows for rapid evaluation of tumorigenicity and efficacy of chemotherapeutic or gene therapy products delivered intratumorally to the pons. View Publication

The realization of personalized medicine through human induced pluripotent stem cell (iPSC) technology can be advanced by transcriptomics,epigenomics,and bioinformatics that inform on genetic pathways directing tissue development and function. When possible,population diversity should be included in new studies as resources become available. Previously we derived replicate iPSC lines of African American,Hispanic-Latino and Asian self-designated ethnically diverse (ED) origins with normal karyotype,verified teratoma formation,pluripotency biomarkers,and tri-lineage in vitro commitment. Here we perform bioinformatics of RNA-Seq and ChIP-seq pluripotency data sets for two replicate Asian and Hispanic-Latino ED-iPSC lines that reveal differences in generation of contractile cardiomyocytes but similar and robust differentiation to multiple neural,pancreatic,and smooth muscle cell types. We identify shared and distinct genes and contributing pathways in the replicate ED-iPSC lines to enhance our ability to understand how reprogramming to iPSC impacts genes and pathways contributing to cardiomyocyte contractility potential. View Publication

Human embryonic stem cells can replicate indefinitely while maintaining their undifferentiated state and,therefore,are immortal in culture. This capacity may demand avoidance of any imbalance in protein homeostasis (proteostasis) that would otherwise compromise stem cell identity. Here we show that human pluripotent stem cells exhibit enhanced assembly of the TRiC/CCT complex,a chaperonin that facilitates the folding of 10% of the proteome. We find that ectopic expression of a single subunit (CCT8) is sufficient to increase TRiC/CCT assembly. Moreover,increased TRiC/CCT complex is required to avoid aggregation of mutant Huntingtin protein. We further show that increased expression of CCT8 in somatic tissues extends Caenorhabditis elegans lifespan in a TRiC/CCT-dependent manner. Ectopic expression of CCT8 also ameliorates the age-associated demise of proteostasis and corrects proteostatic deficiencies in worm models of Huntington's disease. Our results suggest proteostasis is a common principle that links organismal longevity with hESC immortality. View Publication