Photoreceptor laminin drives differentiation of human pluripotent stem cells to photoreceptor progenitors that partially restore retina function.

Blindness caused by advanced stages of inherited retinal diseases and age-related macular degeneration are characterized by photoreceptor loss. Cell therapy involving replacement with functional photoreceptor-like cells generated from human pluripotent stem cells holds great promise. Here, we generated a human recombinant retina-specific laminin isoform, LN523, and demonstrated the role in promoting the differentiation of human embryonic stem cells into photoreceptor progenitors.

Molecular profiling of stem cell-derived retinal pigment epithelial cell differentiation established for clinical translation.

Human embryonic stem cell-derived retinal pigment epithelial cells (hESC-RPE) are a promising cell source to treat age-related macular degeneration (AMD). Despite several ongoing clinical studies, a detailed mapping of transient cellular states during in vitro differentiation has not been performed. Here, we conduct single-cell transcriptomic profiling of an hESC-RPE differentiation protocol that has been developed for clinical use.

Publisher Correction: Identification of cell surface markers and establishment of monolayer differentiation to retinal pigment epithelial cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Publisher Correction: Identification of cell surface markers and establishment of monolayer differentiation to retinal pigment epithelial cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Preclinical safety studies of human embryonic stem cell-derived retinal pigment epithelial cells for the treatment of age-related macular degeneration.

As pluripotent stem cell (PSC)-based reparative cell therapies are reaching the bedside, there is a growing need for the standardization of studies concerning safety of the derived products. Clinical trials using these promising strategies are in development, and treatment for age-related macular degeneration is one of the first that has reached patients. We have previously established a xeno-free and defined differentiation protocol to generate functional human embryonic stem cells (hESCs)-derived retinal pigment epithelial (RPE) cells.

Identification of cell surface markers and establishment of monolayer differentiation to retinal pigment epithelial cells.

In vitro differentiation of human pluripotent stem cells into functional retinal pigment epithelial (RPE) cells provides a potentially unlimited source for cell based reparative therapy of age-related macular degeneration. Although the inherent pigmentation of the RPE cells have been useful to grossly evaluate differentiation efficiency and allowed manual isolation of pigmented structures, accurate quantification and automated isolation has been challenging. To address this issue, here we perform a comprehensive antibody screening and identify cell surface markers for RPE cells.

Generation of Retinal Pigment Epithelial Cells Derived from Human Embryonic Stem Cells Lacking Human Leukocyte Antigen Class I and II.

Human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells could serve as a replacement therapy in advanced stages of age-related macular degeneration. However, allogenic hESC-RPE transplants trigger immune rejection, supporting a strategy to evade their immune recognition. We established single-knockout beta-2 microglobulin (SKO-B2M), class II major histocompatibility complex transactivator (SKO-CIITA) and double-knockout (DKO) hESC lines that were further differentiated into corresponding hESC-RPE lines lacking either surface human leukocyte antigen class I (HLA-I) or HLA-II, or both.

Subretinal Transplantation of Human Embryonic Stem Cell Derived-retinal Pigment Epithelial Cells into a Large-eyed Model of Geographic Atrophy.

Geographic atrophy (GA), the late stage of dry age-related macular degeneration is characterized by loss of the retinal pigment epithelial (RPE) layer, which leads to subsequent degeneration of vital retinal structures (e.g., photoreceptors) causing severe vision impairment.

Integration of Subretinal Suspension Transplants of Human Embryonic Stem Cell-Derived Retinal Pigment Epithelial Cells in a Large-Eyed Model of Geographic Atrophy.

Purpose: Subretinal suspension transplants of human embryonic stem cell-derived retinal pigment epithelial cells (hESC-RPE) have the capacity to form functional monolayers in naive eyes. We explore hESC-RPE integration when transplanted in suspension to a large-eyed model of geographic atrophy (GA).

Methods: Derivation of hESC-RPE was performed in a xeno-free and defined manner.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF THE FOVEAL MICROVASCULATURE IN GEOGRAPHIC ATROPHY.

Purpose: To examine the retinal and choroidal foveal and parafoveal vasculature in patients with bilateral geographic atrophy (GA) secondary to age-related macular degeneration using optical coherence tomography angiography (OCTA).

Methods: Fourteen eyes from 7 patients with and without fovea-sparing bilateral GA at St. Erik Eye Hospital.

Xeno-Free and Defined Human Embryonic Stem Cell-Derived Retinal Pigment Epithelial Cells Functionally Integrate in a Large-Eyed Preclinical Model.

Human embryonic stem cell (hESC)-derived retinal pigment epithelial (RPE) cells could replace lost tissue in geographic atrophy (GA) but efficacy has yet to be demonstrated in a large-eyed model. Also, production of hESC-RPE has not yet been achieved in a xeno-free and defined manner, which is critical for clinical compliance and reduced immunogenicity. Here we describe an effective differentiation methodology using human laminin-521 matrix with xeno-free and defined medium.

In Vivo Imaging of Subretinal Bleb-Induced Outer Retinal Degeneration in the Rabbit.

Purpose: To analyze the morphologic effects of subretinal blebs in rabbits using real-time imaging by spectral-domain optical coherence tomography (SD-OCT), infrared-confocal scanning laser ophthalmoscopy (IR-cSLO), and blue-light fundus autofluorescence (BAF).

Methods: Subretinal blebs of PBS or balanced salt solution (BSS) were induced in albino or pigmented rabbits using a transvitreal pars plana technique. Spectral-domain optical coherence tomography, IR-cSLO, and BAF were done at multiple intervals for up to 12 weeks after subretinal bleb injection.

HMGA2 and MDM2 expression in lipomatous tumors with partial, low-level amplification of sequences from the long arm of chromosome 12.

Ordinary lipomas are cytogenetically characterized primarily by simple balanced chromosome aberrations with stable morphologies, most of which affect chromosome segment, 12q13-15, where the HMGA2 gene plays a key pathogenetic role. Atypical lipomatous tumors (ALTs) display supernumerary ring or giant marker chromosomes with amplification of several genes including HMGA2 and MDM2. A study of HMGA2 expression in a variety of adipocytic tumors showed aberrant expression in lipomas with 12q13-15 aberrations and ring chromosomes as well as in ALTs and well-differentiated liposarcomas (WDLSs), and frequent differential expression of HMGA2 exons 1-2 versus that of exons 4-5.

Gene expression and single nucleotide polymorphism array analyses of spindle cell lipomas and conventional lipomas with 13q14 deletion.

Spindle cell lipomas (SCL) are circumscribed, usually s.c. tumors that typically occur on the posterior neck, shoulder, and back of middle aged men.

Fusion of the FUS and CREB3L2 genes in a supernumerary ring chromosome in low-grade fibromyxoid sarcoma.

Low-grade fibromyxoid sarcoma (LGFMS) is a rare, low-grade malignant soft tissue tumor that is often mistaken for either benign or more malignant tumor types. Commonly, this tumor affects young adults and typically arises in the deep proximal extremities or trunk with frequent recurrences and can metastasize to the lungs many years later. Most cases have a recurrent balanced translocation involving chromosomes 7 and 16, t(7;16)(q32-34;p11), which leads to the fusion of the FUS and CREB3L2 genes.

Expression levels of HMGA2 in adipocytic tumors correlate with morphologic and cytogenetic subgroups.

Background: The HMGA2 gene encodes a protein that alters chromatin structure. Deregulation, typically through chromosomal rearrangements, of HMGA2 has an important role in the development of several mesenchymal neoplasms. These rearrangements result in the expression of a truncated protein lacking the acidic C-terminus, a fusion protein consisting of the AT-hook domains encoded by exons 1-3 and parts from another gene, or a full-length protein; loss of binding sites for regulatory microRNA molecules from the 3' untranslated region (UTR) of HMGA2 has been suggested to be a common denominator.

Cytogenetic and molecular cytogenetic findings in lipoblastoma.

Lipoblastoma is a rare benign tumor that arises from embryonic adipose tissue and usually occurs in young children. Here, we present a review of available cytogenetic data and the karyotypes of 10 new cases of lipoblastoma, of which 7 could be studied further by fluorescence in situ hybridization (FISH) with regard to the involvement of the PLAG1 gene. All seven tumors with clonal aberrations harbored breakpoints in 8q11 approximately q13, in agreement with literature data.

Assessment of the clinical and molecular impact of different cytogenetic subgroups in a series of 272 lipomas with abnormal karyotype.

Conventional lipomas harbor karyotypic changes that could be subdivided into four, usually mutually exclusive, categories: rearrangement, in particular through translocations, of chromosome bands 12q13-15, resulting in deregulation of the HMGA2 gene, loss of material from or rearrangement of chromosome 13, supernumerary ring or giant marker chromosomes, and aberrations of chromosome band 6p21. In the present study, 272 conventional lipomas, two-thirds of them deep-seated, with acquired clonal chromosome changes were assessed with regard to karyotypic and clinical features. A nonrandom distribution of breakpoints and imbalances could be confirmed, with 83% of the cases harboring one or more of the previously known cytogenetic hallmarks.