title: Loss of MITF expression during human embryonic stem cell differentiation disrupts retinal pigment epithelium development and optic vesicle cell proliferation.
abstract: Microphthalmia-associated transcription factor (MITF) is a master regulator of pigmented cell survival and differentiation with direct transcriptional links to cell cycle, apoptosis and pigmentation. In mouse, Mitf is expressed early and uniformly in optic vesicle (OV) cells as they evaginate from the developing neural tube, and null Mitf mutations result in microphthalmia and pigmentation defects. However, homozygous mutations in MITF have not been identified in humans; therefore, little is known about its role in human retinogenesis. We used a human embryonic stem cell (hESC) model that recapitulates numerous aspects of retinal development, including OV specification and formation of retinal pigment epithelium (RPE) and neural retina progenitor cells (NRPCs), to investigate the earliest roles of MITF. During hESC differentiation toward a retinal lineage, a subset of MITF isoforms was expressed in a sequence and tissue distribution similar to that observed in mice. In addition, we found that promoters for the MITF-A, -D and -H isoforms were directly targeted by Visual Systems Homeobox 2 (VSX2), a transcription factor involved in patterning the OV toward a NRPC fate. We then manipulated MITF RNA and protein levels at early developmental stages and observed decreased expression of eye field transcription factors, reduced early OV cell proliferation and disrupted RPE maturation. This work provides a foundation for investigating MITF and other highly complex, multi-purposed transcription factors in a dynamic human developmental model system.
authors.affiliation: Waisman Center.
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Capowski
authors.affiliation: Waisman Center.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Simonett
authors.affiliation: Waisman Center.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Clark
authors.affiliation: Waisman Center.
authors.forename: Lynda S
authors.initials: LS
authors.lastname: Wright
authors.affiliation: Morgridge Institute for Research, Madison, WI 53715, USA.
authors.forename: Sara E
authors.initials: SE
authors.lastname: Howden
authors.affiliation: Waisman Center.
authors.forename: Kyle A
authors.initials: KA
authors.lastname: Wallace
authors.affiliation: Waisman Center.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Petelinsek
authors.affiliation: Department of Ophthalmology, University Hospital Lozano Blesa, Zaragoza 50009, Spain, Aragon Institute of Health Sciences, Zaragoza 50009, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Pinilla
authors.affiliation: Waisman Center, McPherson Eye Research Institute and.
authors.forename: M Joseph
authors.initials: MJ
authors.lastname: Phillips
authors.affiliation: Department of Biology, Indiana University-Purdue University, Indianapolis, IN 46202, USA.
authors.forename: Jason S
authors.initials: JS
authors.lastname: Meyer
authors.affiliation: Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Bernard L
authors.initials: BL
authors.lastname: Schneider
authors.affiliation: Morgridge Institute for Research, Madison, WI 53715, USA, Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53715, USA and Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Thomson
authors.affiliation: Waisman Center, McPherson Eye Research Institute and Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53705, USA, dgamm@wisc.edu.
authors.forename: David M
authors.initials: DM
authors.lastname: Gamm
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D049109:Cell Proliferation; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D055786:Gene Knockout Techniques; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D051379:Mice; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics* / Q000378:metabolism; D058953:Neural Stem Cells / Q000166:cytology / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; C497234:MITF protein, human; D051739:Microphthalmia-Associated Transcription Factor; D020033:Protein Isoforms; D014157:Transcription Factors; C490289:VSX2 protein, human