Single-cell RNA sequencing reveals sexual diversity in the human bladder and its prospective impacts on bladder cancer and urinary tract infection.

BACKGROUND: Some bladder-related diseases, such as bladder urinary tract infection (UTI) and bladder cancer (BCa), have significant six differences in incidence and prognosis. However, the molecular mechanisms underlying these sex differences are still not fully understood. Understanding the sex-biased differences in gene expression in normal bladder cells can help resolve these problems. METHODS: We first collected published single-cell RNA sequencing (scRNA-seq) data of normal human bladders from females and males to map the bladder transcriptomic landscape. Then, Gene Ontology (GO) analysis and gene set enrichment analysis (GSEA) were used to determine the significant pathways that changed in the specific cell populations. The Monocle2 package was performed to reconstruct the differentiation trajectories of fibroblasts. In addition, the scMetabolism package was used to analyze the metabolic activity at the single-cell level, and the SCENIC package was used to analyze the regulatory network. RESULTS: In total, 27,437 cells passed stringent quality control, and eight main cell types in human bladder were identified according to classical markers. Sex-based differential gene expression profiles were mainly observed in human bladder urothelial cells, fibroblasts, B cells, and T cells. We found that urothelial cells in males demonstrated a higher growth rate. Moreover, female fibroblasts produced more extracellular matrix, including seven collagen genes that may mediate BCa progression. Furthermore, the results showed that B cells in female bladders exhibited more B-cell activated signals and a higher expression of immunoglobulin genes. We also found that T cells in female bladders exhibited more T-cell activated signals. These different biological functions and properties of these cell populations may correlate with sex differences in UTI and BCa, and result in different disease processes and outcomes. CONCLUSIONS: Our study provides reasonable insights for further studies of sex-based physiological and pathological disparities in the human bladder, which will contribute to the understanding of epidemiological differences in UTI and BCa.

Single-cell transcriptomics reveals cell type diversity of human prostate.

Extensive studies have been performed to describe the phenotypic changes occurring during malignant transformation of the prostate. However, the cell types and associated changes that contribute to the development of prostate diseases and cancer remain elusive, largely due to the heterogeneous composition of prostatic tissues. Here, we conduct a comprehensive evaluation of four human prostate tissues by single-cell RNA sequencing (scRNA-seq) to analyze their cellular compositions. We identify 18 clusters of cell types, each with distinct gene expression profiles and unique features; of these, one cluster of epithelial cells (Ep) is found to be associated with immune function. In addition, we characterize a special cluster of fibroblasts and aberrant signaling changes associated with prostate cancer (PCa). Moreover, we provide insights into the epithelial changes that occur during the cellular senescence and aging. These results expand our understanding of the unique functional associations between the diverse prostatic cell types and the contributions of specific cell clusters to the malignant transformation of prostate tissues and PCa development.

Carcinogenic effect of adenylosuccinate lyase (ADSL) in prostate cancer development and progression through the cell cycle pathway.

BACKGROUND: Prostate cancer (PCa) is still a serious male malignant disease across the world. However, no exact pathogenesis had been explained. Although adenylosuccinate lyase (ADSL) gene was identified to be important in PCa early in 1987, its comprehensive functions for PCa have not been presented. METHODS: The cBioPortal for Cancer Genomics, Oncomine and GEO database were retrieved to investigate the associations between of the ADSL gene and PCa. Then, the PC-3, DU145 and C4-2B cell lines were applied in vitro experiments. RNA sequencing and further western blot (WB) were applied to explore the potential mechanisms of ADSL gene in PCa. RESULTS: Based on PCa clinical datasets, we firstly found ADSL gene highly expressed in PCa tissues. Moreover, its transcript level increased in the metastatic PCa further. Elevated ADSL gene expression indicated a poor prognosis of PCa. While inhibiting the expression of ADSL with siRNA, the ability of cell proliferation and migration all declined markedly, with increased cell apoptosis inversely. Most of cells were blocked in the G0/G1 phase. Additionally, RNA sequencing also discovered the inactivity of cell cycle pathway after ADSL knockdown, which had also confirmed on the proteins levels. CONCLUSIONS: Our study identified the ADSL as an oncogene of PCa through regulating the cell cycle pathway firstly, with explicit cell and clinical phenotypes. Further mechanisms were needed to confirm its carcinogenic effect.

Uncovering the Pharmacological Mechanism of 2-Dodecyl-6-Methoxycyclohexa-2,5 -Diene-1,4-Dione Against Lung Cancer Based on Network Pharmacology and Experimental Evaluation.

Background: 2-Dodecyl-6-Methoxycyclohexa-2, 5-Diene-1,4-Dione (DMDD) was purified from the roots of Averrhoa carambola L. Previous research demonstrated that DMDD is a small molecular compound with significant therapeutic potential for tumors. However, the potential targets and pharmacological mechanism of DMDD to treat lung cancer has not been reported. Methods: We employed network pharmacology and experimental evaluation to reveal the pharmacological mechanism of DMDD against lung cancer. Potential therapeutic targets of DMDD were screened by PharmMapper. Differentially expressed genes (DEGs) in The Cancer Genome Atlas (TCGA) lung cancer data sets were extracted and analyzed by GEPIA2. The mechanism of DMDD against lung cancer was determined by PPI, gene ontology (GO) and KEGG pathway enrichment analysis. Survival analysis and molecular docking were employed to obtain the key targets of DMDD. Human lung cancer cell lines H1975 and PC9 were used to detect effects of DMDD treatment in vitro. The expression of key targets after DMDD treated was validated by Western Blot. Results: A total of 60 Homo sapiens potential therapeutic targets of DMDD and 3,545 DEGs in TCGA lung cancer datasets were identified. Gene ontology and pathway analysis revealed characteristic of the potential targets of DMDD and DEGs in lung cancer respectively. Cell cycle and pathways in cancer were overlapping with DMDD potential targets and lung cancer DEGs. Eight overlapping genes were found between DMDD potential therapeutic targets and lung cancer related DEGs. Survival analysis showed that high expression of DMDD potential targets CCNE1 and E2F1 was significantly related to poor patient survival in lung cancer. Molecular docking found that DMDD exhibited significant binding affinities within the active site of CCNE1 and E2F1. Further tests showed that DMDD inhibited the proliferation, migration and clone formation in lung cancer cell lines (H1975 and PC9) in a dose and time dependent manner. Mechanistically, DMDD treatment decreased the expression of CDK2, CCNE1, E2F1 proteins and induced cell cycle arrest at the G1/S phase in H1975 and PC9 cells. Conclusion: These results delineated that DMDD holds therapeutic potential that blocks tumorigenesis by cell cycle regulation in lung cancer, and may provide potential therapies for lung cancer.

Current progress in stem cell therapy for type 1 diabetes mellitus.

Type 1 diabetes mellitus (T1DM) is the most common chronic autoimmune disease in young patients and is characterized by the loss of pancreatic ß cells; as a result, the body becomes insulin deficient and hyperglycemic. Administration or injection of exogenous insulin cannot mimic the endogenous insulin secreted by a healthy pancreas. Pancreas and islet transplantation have emerged as promising treatments for reconstructing the normal regulation of blood glucose in T1DM patients. However, a critical shortage of pancreases and islets derived from human organ donors, complications associated with transplantations, high cost, and limited procedural availability remain bottlenecks in the widespread application of these strategies. Attempts have been directed to accommodate the increasing population of patients with T1DM. Stem cell therapy holds great potential for curing patients with T1DM. With the advent of research on stem cell therapy for various diseases, breakthroughs in stem cell-based therapy for T1DM have been reported. However, many unsolved issues need to be addressed before stem cell therapy will be clinically feasible for diabetic patients. In this review, we discuss the current research advances in strategies to obtain insulin-producing cells (IPCs) from different precursor cells and in stem cell-based therapies for diabetes.

SIRPB1 promotes prostate cancer cell proliferation via Akt activation.

BACKGROUND: Signal regulatory protein ß1 (SIRPB1) is a signal regulatory protein member of the immunoglobulin superfamily and is capable of modulating receptor tyrosine kinase-coupled signaling. Copy number variations at the SIRPB1 locus were previously reported to associate with prostate cancer aggressiveness in patients, however, the role of SIRPB1 in prostate carcinogenesis is unknown. METHODS: Fluorescence in situ hybridization and laser-capture microdissection coupled with quantitative polymerase chain reaction was utilized to determine SIRPB1 gene amplification and messenger RNA expression in prostate cancer specimens. The effect of knockdown of SIRPB1 by RNA interference in PC3 prostate cancer cells on cell growth in colony formation assays and cell mobility in wound-healing, transwell assays, and cell cycle analysis was determined. Overexpression of SIPRB1 in C4-2 prostate cancer cells on cell migration, invasion, colony formation and cell cycle progression and tumor take rate in xenografts was also determined. Western blot assay of potential downstream SIRPB1 pathways was also performed. RESULTS: SIRPB1 gene amplification was detected in up to 37.5% of prostate cancer specimens based on in silico analysis of several publicly available datasets. SIRPB1 gene amplification and overexpression were detected in prostate cancer specimens. The knockdown of SIRPB1 significantly suppressed cell growth in colony formation assays and cell mobility. SIRPB1 knockdown also induced cell cycle arrest during the G0 /G1 phase and enhancement of apoptosis. Conversely, overexpression of SIPRB1 in C4-2 prostate cancer cells significantly enhanced cell migration, invasion, colony formation, and cell cycle progression and increased C4-2 xenograft tumor take rate in nude mice. Finally, this study presented evidence for SIRPB1 regulation of Akt phosphorylation and showed that Akt inhibition could abolish SIRPB1 stimulation of prostate cancer cell proliferation. CONCLUSIONS: These results suggest that SIRPB1 is a potential oncogene capable of activating Akt signaling to stimulate prostate cancer proliferation and could be a biomarker for patients at risk of developing aggressive prostate cancer.

Single-cell RNA sequencing of human kidney.

A comprehensive cellular anatomy of normal human kidney is crucial to address the cellular origins of renal disease and renal cancer. Some kidney diseases may be cell type-specific, especially renal tubular cells. To investigate the classification and transcriptomic information of the human kidney, we rapidly obtained a single-cell suspension of the kidney and conducted single-cell RNA sequencing (scRNA-seq). Here, we present the scRNA-seq data of 23,366 high-quality cells from the kidneys of three human donors. In this dataset, we show 10 clusters of normal human renal cells. Due to the high quality of single-cell transcriptomic information, proximal tubule (PT) cells were classified into three subtypes and collecting ducts cells into two subtypes. Collectively, our data provide a reliable reference for studies on renal cell biology and kidney disease.

Single-Cell Transcriptomic Map of the Human and Mouse Bladders.

BACKGROUND: Having a comprehensive map of the cellular anatomy of the normal human bladder is vital to understanding the cellular origins of benign bladder disease and bladder cancer. METHODS: We used single-cell RNA sequencing (scRNA-seq) of 12,423 cells from healthy human bladder tissue samples taken from patients with bladder cancer and 12,884 cells from mouse bladders to classify bladder cell types and their underlying functions. RESULTS: We created a single-cell transcriptomic map of human and mouse bladders, including 16 clusters of human bladder cells and 15 clusters of mouse bladder cells. The homology and heterogeneity of human and mouse bladder cell types were compared and both conservative and heterogeneous aspects of human and mouse bladder evolution were identified. We also discovered two novel types of human bladder cells. One type is ADRA2A+ and HRH2+ interstitial cells which may be associated with nerve conduction and allergic reactions. The other type is TNNT1+ epithelial cells that may be involved with bladder emptying. We verify these TNNT1+ epithelial cells also occur in rat and mouse bladders. CONCLUSIONS: This transcriptomic map provides a resource for studying bladder cell types, specific cell markers, signaling receptors, and genes that will help us to learn more about the relationship between bladder cell types and diseases.

Integrative Analysis of Zika Virus Genome RNA Structure Reveals Critical Determinants of Viral Infectivity.

Zika virus (ZIKV) strains can be classified into the ancestral African and contemporary Asian lineages, with the latter responsible for recent epidemics associated with neurological conditions. To understand how Asian strains lead to exacerbated disease, a crucial step is identifying genomic variations that affect infectivity and pathogenicity. Here we use two high-throughput sequencing approaches to assess RNA secondary structures and intramolecular RNA-RNA interactions in vivo for the RNA genomes of Asian and African ZIKV lineages. Our analysis identified functional RNA structural elements and a functional long-range intramolecular interaction specific for the Asian epidemic strains. Mutants that disrupt this extended RNA interaction between the 5' UTR and the E protein coding region reduce virus infectivity, which is partially rescued with compensatory mutants, restoring this RNA-RNA interaction. These findings illuminate the structural basis of ZIKV regulation and provide a resource for the discovery of RNA structural elements important for ZIKV infection.

Prostate cancer tends to metastasize in the bone-mimicking microenvironment via activating NF-κB signaling.

Prostate cancer preferentially metastasizes to the bone. However, the underlying molecular mechanisms are still unclear. To explore the effects of a bone-mimicking microenvironment on PC3 prostate cancer cell growth and metastasis, we used osteoblast differentiation medium (ODM; minimal essential medium alpha supplemented with L-ascorbic acid) to mimic the bone microenvironment. PC3 cells grown in ODM underwent epithelial-mesenchymal transition and showed enhanced colony formation, migration, and invasion abilities compared to the cells grown in normal medium. PC3 cells grown in ODM showed enhanced metastasis when injected in mice. A screening of signaling pathways related to invasion and metastasis revealed that the NF-κB pathway was activated, which could be reversed by Bay 11-7082, a NF-κB pathway inhibitor. These results indicate that the cells in different culture conditions manifested significantly different biological behaviors and the NF-κB pathway is a potential therapeutic target for prostate cancer bone metastasis.

Tumor microenvironment promotes prostate cancer cell dissemination via the Akt/mTOR pathway.

Metastasis causes high mortality in various malignancies, including prostate cancer (PCa). Accumulating data has suggested that cancer cells spread from the primary tumor to distant sites at early stage, which is characterized by disseminated tumor cells (DTCs). However, lack of direct evidence of partial localized PCa cells occurring epithelial-to-mesenchymal transition (EMT) and disseminating to distant sites (e.g bone marrow). In this study, we used luciferase labeled PCa cells to establish an EMT mouse model and to detect whether DTCs spread into the bone marrow. We observed tumor cells existing in mouse bone marrow when tumor grew subcutaneously at palpable stage. Studies also showed that ex vivo tumor cells exhibited increased proliferative, migratory, invasive and angiogenesis abilities. When compared ex vivo tumor cells with parental cells, hallmarks of EMT including E-cadherin, Vimentin, Snail, and ZO-1 were altered significantly. Specifically, the ex vivo tumor cells showed more mesenchymal properties. Angiogenesis markers, including VEGFR2, VEGFR3, MCP-3, I-TAC, I309, uPAR and GROα, were also increased in the ex vivo tumor cells. Intriguingly, MCP-1 expression was dramatically increased in those cells. Mechanistic analyses indicated that AP1 mediates PCa EMT and the appearance of DTCs via the Akt/mTOR pathway. This study may provide potential therapeutic targets and diagnostic biomarkers of PCa progression and metastasis.

Garcinone C exerts antitumor activity by modulating the expression of ATR/Stat3/4E­BP1 in nasopharyngeal carcinoma cells.

Nasopharyngeal carcinoma (NPC) is one of the most common head and neck malignancies and is typically treated with radiotherapy and chemotherapy. Garcinone C, a natural compound isolated from Garcinia oblongifolia Champ., is a xanthone derivative with potential cytotoxic effects on certain cancers. However, there are limited studies regarding its effects on NPC cells, and its mechanism of action in NPC remains unknown. In the present study, we found that garcinone C significantly inhibited cell viability of the human NPC cell lines CNE1, CNE2, HK1 and HONE1. This inhibition was exerted in a time­ and dose­dependent manner. Flow cytometry demonstrated that garcinone C arrested the cell cycle at the S phase. Moreover, with 10 µM of high­dose garcinone C treatment, the cells exhibited necrotic morphology changes including cell swelling, rough endoplasmic reticulum degranulation, endoplasmic reticulum dilatation, mitochondrial swelling and vacuolar degeneration. In addition, we found that garcinone C stimulated the expression levels of ATR and 4E­BP1, while efficiently inhibiting the expression levels of cyclin B1, cyclin D1, cyclin E2, cdc2, CDK7 and Stat3. Collectively, the ability of garcinone C to inhibit NPC in growth in vitro suggested that garcinone C may be a novel agent for the management of NPC.

C10orf116 Gene Copy Number Loss in Prostate Cancer: Clinicopathological Correlations and Prognostic Significance.

BACKGROUND Prostate cancer (PCa) is the second most commonly diagnosed cancer in males worldwide. This study aimed to identify differentially expressed genes and to investigate the potential correlation between gene abnormalities and clinical features in PCa to evaluate disease progression and prognosis. MATERIAL AND METHODS A total of 4 independent microarrays of PCa patients from the Oncomine database were used to identify differences in expression of genes contributing to cancer progression. Quantitative real-time polymerase chain reaction (RT-qPCR) analysis was used to evaluate the mRNA expression of the target in human prostate cancer cells. To explore the relationship between the DNA copy number alteration and mRNA expression changes, dataset containing copy number alteration, DNA methylation, and gene expression in PCa were obtained from the cBioPortal online platform (n=273). RESULTS We identified 40 genes that were significantly dysregulated in PCa from 4 independent microarrays. Among these, 3 genes showed a consistent change of over 2-fold in the 4 microarrays. The mRNA expression of C10orf116 showed consistent expression in prostate cancer cells compared with that in prostate gland cells as assessed by RT-qPCR. Moreover, C10orf116 loss was associated with poor distant relapse-free survival (DFS) by analyzing data of 273 PCa patients, but it was not identified as an independent prognostic risk factor for DFS. In addition, we found that C10orf116 loss was associated with higher pathological stage, higher clinical stage, and lymph node metastasis in PCa, and that C10orf116 copy number was highly correlated with PTEN copy number and mRNA expression. CONCLUSIONS As a predictive indicator, C10orf116 loss contributes to our understating of the biology of aggressive changes in PCa and also helps evaluate the prognosis of patients.

MRI tracking of autologous pancreatic progenitor-derived insulin-producing cells in monkeys.

Insulin-producing cells (IPCs) derived from a patient's own stem cells offer great potential for autologous transplantation in diabetic patients. However, the limited survival of engrafted cells remains a bottleneck in the application of this strategy. The present study aimed to investigate whether nanoparticle-based magnetic resonance (MR) tracking can be used to detect the loss of grafted stem cell-derived IPCs in a sensitive and timely manner in a diabetic monkey model. Pancreatic progenitor cells (PPCs) were isolated from diabetic monkeys and labeled with superparamagnetic iron oxide nanoparticles (SPIONs). The SPION-labeled cells presented as hypointense signals on MR imaging (MRI). The labeling procedure did not affect the viability or IPC differentiation of PPCs. Importantly, the total area of the hypointense signal caused by SPION-labeled IPCs on liver MRI decreased before the decline in C-peptide levels after autotransplantation. Histological analysis revealed no detectable immune response to the grafts and many surviving insulin- and Prussian blue-positive cell clusters on liver sections at one year post-transplantation. Collectively, this study demonstrates that SPIO nanoparticles can be used to label stem cells for noninvasive, sensitive, longitudinal monitoring of stem cell-derived IPCs in large animal models using a conventional MR imager.

Down-regulation of E-cadherin enhances prostate cancer chemoresistance via Notch signaling.

BACKGROUND: The chemoresistance of prostate cancer (PCa) is invariably associated with the aggressiveness and metastasis of this disease. New emerging evidence indicates that the epithelial-to-mesenchymal transition (EMT) may play pivotal roles in the development of chemoresistance and metastasis. As a hallmark of EMT, E-cadherin is suggested to be a key marker in the development of chemoresistance. However, the molecular mechanisms underlying PCa chemoresistance remain unclear. The current study aimed to explore the association between EMT and chemoresistance in PCa as well as whether changing the expression of E-cadherin would affect PCa chemoresistance. METHODS: Parental PC3 and DU145 cells and their chemoresistant PC3-TxR and DU145-TxR cells were analyzed. PC3-TxR and DU145-TxR cells were transfected with E-cadherin-expressing lentivirus to overexpress E-cadherin; PC3 and DU145 cells were transfected with small interfering RNA to silence E-cadherin. Changes of EMT phenotype-related markers and signaling pathways were assessed by Western blotting and quantitative real-time polymerase chain reaction. Tumor cell migration, invasion, and colony formation were then evaluated by wound healing, transwell, and colony formation assays, respectively. The drug sensitivity was evaluated using MTS assay. RESULTS: Chemoresistant PC3-TxR and DU145-TxR cells exhibited an invasive and metastatic phenotype that associated with EMT, including the down-regulation of E-cadherin and up-regulation of Vimentin, Snail, and N-cadherin, comparing with that of parental PC3 and DU145 cells. When E-cadherin was overexpressed in PC3-TxR and DU145-TxR cells, the expression of Vimentin and Claudin-1 was down-regulated, and tumor cell migration and invasion were inhibited. In particular, the sensitivity to paclitaxel was reactivated in E-cadherin-overexpressing PC3-TxR and DU145-TxR cells. When E-cadherin expression was silenced in parental PC3 and DU145 cells, the expression of Vimentin and Snail was up-regulated, and, particularly, the sensitivity to paclitaxel was decreased. Interestingly, Notch-1 expression was up-regulated in PC3-TxR and DU145-TxR cells, whereas the E-cadherin expression was down-regulated in these cells comparing with their parental cells. The use of γ-secretase inhibitor, a Notch signaling pathway inhibitor, significantly increased the sensitivity of chemoresistant cells to paclitaxel. CONCLUSION: The down-regulation of E-cadherin enhances PCa chemoresistance via Notch signaling, and inhibiting the Notch signaling pathway may reverse PCa chemoresistance.

MEK inhibitor diminishes nasopharyngeal carcinoma (NPC) cell growth and NPC-induced osteoclastogenesis via modulating CCL2 and CXCL16 expressions.

Nasopharyngeal carcinoma (NPC) is a common malignancy in southern China and Southeast Asia. NPC frequently metastasizes to the bone in advanced patients resulting in high mortality. The molecular mechanisms for NPC development and cancer-induced bone lesions are unclear. In this study, we firstly determined chemokine receptor CCR2 and CXCR6 expressions in clinical specimens and CNE2, SUNE1, CNE1, and HK1 cell lines. Then, we measured chemokine CCL2 and CXCL16 production in these NPC cell lines by ELISA. Expression levels of these chemokines and their receptors were observed to positively correlate with tumor aggressiveness. Furthermore, U0126 (MEK inhibitor) was used to treat these NPC cell lines. CCL2 and CXCL16 expression levels and cell proliferation were significantly inhibited by U0126 in a dose- and time-dependent manner. Finally, we collected conditioned medium (CM) from NPC cell cultures in the presence of U0126 treatment. When mouse bone marrow non-adherent cells were treated with the CM, the numbers of multinucleated osteoclast formation were dramatically diminished. These results indicate that MEK inhibitor diminishes NPC cell proliferation and NPC-induced osteoclastogenesis via modulating CCL2 and CXCL16 expressions. This study provides novel therapeutic targets such as CCL2/CCR2 and CXCL16/CXCR6 for advanced NPC patients.

Autologous iPSC-derived dopamine neuron transplantation in a nonhuman primate Parkinson's disease model.

Autologous dopamine (DA) neurons are a new cell source for replacement therapy of Parkinson's disease (PD). In this study, we tested the safety and efficacy of autologous induced pluripotent stem cell (iPSC)-derived DA cells for treatment of a cynomolgus monkey PD model. Monkey bone marrow mesenchymal cells were isolated and induced to iPSCs, followed by differentiation into DA cells using a method with high efficiency. Autologous DA cells were introduced into the brain of a cynomolgus monkey PD model without immunosuppression; three PD monkeys that had received no grafts served as controls. The PD monkey that had received autologous grafts experienced behavioral improvement compared with that of controls. Histological analysis revealed no overgrowth of grafts and a significant number of surviving A9 region-specific graft-derived DA neurons. The study provided a proof-of-principle to employ iPSC-derived autologous DA cells for PD treatment using a nonhuman primate PD model.

Autologous transplantation of GDNF-expressing mesenchymal stem cells protects against MPTP-induced damage in cynomolgus monkeys.

Glial cell-derived neurotrophic factor (GDNF) has shown beneficial effects in models of Parkinson's disease. The mild results observed in the double-blind clinical trial by intraputamenal infusion of recombinant GDNF proteins warrant a search for alternative delivery methods. In this study, we investigated the function of autologous mesenchymal stem cells (MSCs) expressing GDNF (GDNF-MSCs) for protection against MPTP-induced injury in cynomolgus monkeys. MSCs were obtained from the bone marrow of individual monkeys and gene-modified to express GDNF. Following unilateral engraftment of GDNF-MSCs into the striatum and substantia nigra, the animals were challenged with MPTP to induce a stable systemic Parkinsonian state. The motor functions were spared in the contralateral limbs of monkeys receiving GDNF-MSCs, but not in those receiving MSCs alone. In the striatum of the grafted hemisphere, dopamine levels were higher and dopamine uptake was enhanced. The results suggest that autologous MSCs may be a safe vehicle to deliver GDNF for enhancing nigro-striatum functions.

Low incidence of DNA sequence variation in human induced pluripotent stem cells generated by nonintegrating plasmid expression.

The utility of induced pluripotent stem cells (iPSCs) as models to study diseases and as sources for cell therapy depends on the integrity of their genomes. Despite recent publications of DNA sequence variations in the iPSCs, the true scope of such changes for the entire genome is not clear. Here we report the whole-genome sequencing of three human iPSC lines derived from two cell types of an adult donor by episomal vectors. The vector sequence was undetectable in the deeply sequenced iPSC lines. We identified 1,058-1,808 heterozygous single-nucleotide variants (SNVs), but no copy-number variants, in each iPSC line. Six to twelve of these SNVs were within coding regions in each iPSC line, but ~50% of them are synonymous changes and the remaining are not selectively enriched for known genes associated with cancers. Our data thus suggest that episome-mediated reprogramming is not inherently mutagenic during integration-free iPSC induction.

Efficient derivation and genetic modifications of human pluripotent stem cells on engineered human feeder cell lines.

Derivation of pluripotent stem cells (iPSCs) induced from somatic cell types and the subsequent genetic modifications of disease-specific or patient-specific iPSCs are crucial steps in their applications for disease modeling as well as future cell and gene therapies. Conventional procedures of these processes require co-culture with primary mouse embryonic fibroblasts (MEFs) to support self-renewal and clonal growth of human iPSCs as well as embryonic stem cells (ESCs). However, the variability of MEF quality affects the efficiencies of all these steps. Furthermore, animal sourced feeders may hinder the clinical applications of human stem cells. In order to overcome these hurdles, we established immortalized human feeder cell lines by stably expressing human telomerase reverse transcriptase, Wnt3a, and drug resistance genes in adult mesenchymal stem cells. Here, we show that these immortalized human feeders support efficient derivation of virus-free, integration-free human iPSCs and long-term expansion of human iPSCs and ESCs. Moreover, the drug-resistance feature of these feeders also supports nonviral gene transfer and expression at a high efficiency, mediated by piggyBac DNA transposition. Importantly, these human feeders exhibit superior ability over MEFs in supporting homologous recombination-mediated gene targeting in human iPSCs, allowing us to efficiently target a transgene into the AAVS1 safe harbor locus in recently derived integration-free iPSCs. Our results have great implications in disease modeling and translational applications of human iPSCs, as these engineered human cell lines provide a more efficient tool for genetic modifications and a safer alternative for supporting self-renewal of human iPSCs and ESCs.