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Gai, Xiaowu

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Gai

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Xiaowu

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Gai, Xiaowu

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2008 - 200912010 - 20151

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Author's Publications: search.filters.isAuthorOfPublication.cf9320c2-875a-404e-8df1-6a314b6cb72f

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    Characterization of cells from patient-derived fibrovascular membranes in proliferative diabetic retinopathy
    (Molecular Vision, 2015) Kim, Leo; Wong, Lindsay L.; Amarnani, Dhanesh; Bigger-Allen, Alexander A.; Hu, Yang; Marko, Christina K.; Eliott, Dean; Shah, Vinay A.; McGuone, Declan; Stemmer-Rachamimov, Anat; Gai, Xiaowu; D’Amore, Patricia A.; Arboleda-Velasquez, Joseph
    Purpose Epiretinal fibrovascular membranes (FVMs) are a hallmark of proliferative diabetic retinopathy (PDR). Surgical removal of FVMs is often indicated to treat tractional retinal detachment. This potentially informative pathological tissue is usually disposed of after surgery without further examination. We developed a method for isolating and characterizing cells derived from FVMs and correlated their expression of specific markers in culture with that in tissue. Methods: FVMs were obtained from 11 patients with PDR during diabetic vitrectomy surgery and were analyzed with electron microscopy (EM), comparative genomic hybridization (CGH), immunohistochemistry, and/or digested with collagenase II for cell isolation and culture. Antibody arrays and enzyme-linked immunosorbent assay (ELISA) were used to profile secreted angiogenesis-related proteins in cell culture supernatants. Results: EM analysis of the FVMs showed abnormal vessels composed of endothelial cells with large nuclei and plasma membrane infoldings, loosely attached perivascular cells, and stromal cells. The cellular constituents of the FVMs lacked major chromosomal aberrations as shown with CGH. Cells derived from FVMs (C-FVMs) could be isolated and maintained in culture. The C-FVMs retained the expression of markers of cell identity in primary culture, which define specific cell populations including CD31-positive, alpha-smooth muscle actin-positive (SMA), and glial fibrillary acidic protein-positive (GFAP) cells. In primary culture, secretion of angiopoietin-1 and thrombospondin-1 was significantly decreased in culture conditions that resemble a diabetic environment in SMA-positive C-FVMs compared to human retinal pericytes derived from a non-diabetic donor. Conclusions: C-FVMs obtained from individuals with PDR can be isolated, cultured, and profiled in vitro and may constitute a unique resource for the discovery of cell signaling mechanisms underlying PDR that extends beyond current animal and cell culture models.
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    A GATA-1-regulated microRNA locus essential for erythropoiesis
    (Proceedings of the National Academy of Sciences, 2008) Dore, L. C.; Amigo, J. D.; Dos Santos, Carolina; Zhang, Z.; Gai, Xiaowu; Tobias, J. W.; Yu, D.; Klein, A. M.; Dorman, C.; Wu, W.; Hardison, R. C.; Paw, Barry Htin; Weiss, M. J.
    MicroRNAs (miRNAs) control tissue development, but their mechanism of regulation is not well understood. We used a gene complementation strategy combined with microarray screening to identify miRNAs involved in the formation of erythroid (red blood) cells. Two conserved miRNAs, miR 144 and miR 451, emerged as direct targets of the critical hematopoietic transcription factor GATA-1. In vivo, GATA-1 binds a distal upstream regulatory element to activate RNA polymerase II-mediated transcription of a single common precursor RNA (pri-miRNA) encoding both mature miRNAs. Zebrafish embryos depleted of miR 451 by using antisense morpholinos form erythroid precursors, but their development into mature circulating red blood cells is strongly and specifically impaired. These results reveal a miRNA locus that is required for erythropoiesis and uncover a new regulatory axis through which GATA-1 controls this process.