Publications by authors named "Helen L Spencer"

Aims: Long non-coding RNAs (lncRNAs) play functional roles in physiology and disease, yet understanding of their contribution to endothelial cell (EC) function is incomplete. We identified lncRNAs regulated during EC differentiation and investigated the role of LINC00961 and its encoded micropeptide, small regulatory polypeptide of amino acid response (SPAAR), in EC function.

Methods And Results: Deep sequencing of human embryonic stem cell differentiation to ECs was combined with Encyclopedia of DNA Elements (ENCODE) RNA-seq data from vascular cells, identifying 278 endothelial enriched genes, including 6 lncRNAs.

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Objective- To determine the role of the oncofetal protein TPBG (trophoblast glycoprotein) in normal vascular function and reparative vascularization. Approach and Results- Immunohistochemistry of human veins was used to show TPBG expression in vascular smooth muscle cells and adventitial pericyte-like cells (APCs). ELISA, Western blot, immunocytochemistry, and proximity ligation assays evidenced a hypoxia-dependent upregulation of TPBG in APCs not found in vascular smooth muscle cells or endothelial cells.

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Pluripotent stem cell-derived differentiated endothelial cells offer high potential in regenerative medicine in the cardiovascular system. With the aim of translating the use of a human stem cell-derived endothelial cell product (hESC-ECP) for treatment of critical limb ischemia (CLI) in man, we report a good manufacturing practice (GMP)-compatible protocol and detailed cell tracking and efficacy data in multiple preclinical models. The clinical-grade cell line RC11 was used to generate hESC-ECP, which was identified as mostly endothelial (60% CD31/CD144), with the remainder of the subset expressing various pericyte/mesenchymal stem cell markers.

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Background: Living grafts produced by combining autologous heart-resident stem/progenitor cells and tissue engineering could provide a new therapeutic option for definitive correction of congenital heart disease. The aim of the study was to investigate the antigenic profile, expansion/differentiation capacity, paracrine activity, and pro-angiogenic potential of cardiac pericytes and to assess their engrafting capacity in clinically certified prosthetic grafts.

Methods And Results: CD34(pos) cells, negative for the endothelial markers CD31 and CD146, were identified by immunohistochemistry in cardiac leftovers from infants and children undergoing palliative repair of congenital cardiac defects.

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Introduction: Chemokine-directed migration is crucial for homing of regenerative cells to the infarcted heart and correlates with outcomes of cell therapy trials. Hence, transplantation of chemokine-responsive bone marrow cells may be ideal for treatment of myocardial ischemia. To verify the therapeutic activity of bone marrow mononuclear cells (BM-MNCs) selected by in vitro migration towards the chemokine stromal cell-derived factor-1 (SDF-1) in a mouse model of myocardial infarction (MI), we used BM-MNCs from patients with previous large MI recruited in the TransACT-1&2 cell therapy trials.

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Rationale: Optimization of cell therapy for cardiac repair may require the association of different cell populations with complementary activities.

Objective: Compare the reparative potential of saphenous vein-derived pericytes (SVPs) with that of cardiac stem cells (CSCs) in a model of myocardial infarction, and investigate whether combined cell transplantation provides further improvements.

Methods And Results: SVPs and CSCs were isolated from vein leftovers of coronary artery bypass graft surgery and discarded atrial specimens of transplanted hearts, respectively.

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Objective: We investigated the association between the functional, epigenetic, and expressional profile of human adventitial progenitor cells (APCs) and therapeutic activity in a model of limb ischemia.

Approach And Results: Antigenic and functional features were analyzed throughout passaging in 15 saphenous vein (SV)-derived APC lines, of which 10 from SV leftovers of coronary artery bypass graft surgery and 5 from varicose SV removal. Moreover, 5 SV-APC lines were transplanted (8×10(5) cells, IM) in mice with limb ischemia.

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Ischemia is a leading cause of death in the western world. Regenerative medicine aims to improve healing of ischemic injury by complementing pharmacologic/interventional treatments. Navigating regenerative therapies from 'bench-to-bedside' is a multistep time-consuming process, balancing cell expansion, purity, safety and efficacy while complying with regulatory guidelines.

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Brittle cornea syndrome (BCS; MIM 229200) is an autosomal recessive generalized connective tissue disorder caused by mutations in ZNF469 and PRDM5. It is characterized by extreme thinning and fragility of the cornea that may rupture in the absence of significant trauma leading to blindness. Keratoconus or keratoglobus, high myopia, blue sclerae, hyperelasticity of the skin without excessive fragility, and hypermobility of the small joints are additional features of BCS.

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Brittle cornea syndrome (BCS) is an autosomal recessive disorder characterised by extreme corneal thinning and fragility. Corneal rupture can therefore occur either spontaneously or following minimal trauma in affected patients. Two genes, ZNF469 and PRDM5, have now been identified, in which causative pathogenic mutations collectively account for the condition in nearly all patients with BCS ascertained to date.

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A novel gene, TMEM114, was annotated as a member of the claudin gene family and was subsequently associated as a cause of autosomal dominant cataract because of a translocation in its putative promoter. Our bioinformatic and molecular analyses of TMEM114, and the closely related TMEM235, demonstrate that these proteins are more closely related to members of the voltage dependent calcium channel gamma subunit family. TMEM114 and TMEM235 differed from claudins in terms of localisation in polarised epithelial cells and by the presence of N-linked glycans.

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Extreme corneal fragility and thinning, which have a high risk of catastrophic spontaneous rupture, are the cardinal features of brittle cornea syndrome (BCS), an autosomal-recessive generalized connective tissue disorder. Enucleation is frequently the only management option for this condition, resulting in blindness and psychosocial distress. Even when the cornea remains grossly intact, visual function could also be impaired by a high degree of myopia and keratoconus.

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Objective: To develop an embryoid body-free directed differentiation protocol for the rapid generation of functional vascular endothelial cells derived from human embryonic stem cells (hESCs) and to assess the system for microRNA regulation and angiogenesis.

Methods And Results: The production of defined cell lineages from hESCs is a critical requirement for evaluating their potential in regenerative medicine. We developed a feeder- and serum-free protocol.

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The use of gene mutation/knock-out strategies in mouse embryonic stem (ES) cells has revolutionized the study of gene function in ES cells and embryonic development. However, the construction of vectors for homologous recombination strategies requires considerable expertise and time. We describe two novel vectors that can generate site specific knock-out or EGFP knock-in ES cells within 6 weeks from construct design to identification of positive ES cell clones.

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Epithelial-mesenchymal transition (EMT) events occur during embryonic development and are important for the metastatic spread of epithelial tumors. We show here that spontaneous differentiation of mouse embryonic stem (ES) cells is associated with an E- to N-cadherin switch, up-regulation of E-cadherin repressor molecules (Snail and Slug proteins), gelatinase activity (matrix metalloproteinase [MMP]-2 and -9), and increased cellular motility, all characteristic EMT events. The 5T4 oncofetal antigen, previously shown to be associated with very early ES cell differentiation and altered motility, is also a part of this coordinated process.

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