title: ABCB5 is a limbal stem cell gene required for corneal development and repair.
abstract: Corneal epithelial homeostasis and regeneration are sustained by limbal stem cells (LSCs), and LSC deficiency is a major cause of blindness worldwide. Transplantation is often the only therapeutic option available to patients with LSC deficiency. However, while transplant success depends foremost on LSC frequency within grafts, a gene allowing for prospective LSC enrichment has not been identified so far. Here we show that ATP-binding cassette, sub-family B, member 5 (ABCB5) marks LSCs and is required for LSC maintenance, corneal development and repair. Furthermore, we demonstrate that prospectively isolated human or murine ABCB5-positive LSCs possess the exclusive capacity to fully restore the cornea upon grafting to LSC-deficient mice in xenogeneic or syngeneic transplantation models. ABCB5 is preferentially expressed on label-retaining LSCs in mice and p63α-positive LSCs in humans. Consistent with these findings, ABCB5-positive LSC frequency is reduced in LSC-deficient patients. Abcb5 loss of function in Abcb5 knockout mice causes depletion of quiescent LSCs due to enhanced proliferation and apoptosis, and results in defective corneal differentiation and wound healing. Our results from gene knockout studies, LSC tracing and transplantation models, as well as phenotypic and functional analyses of human biopsy specimens, provide converging lines of evidence that ABCB5 identifies mammalian LSCs. Identification and prospective isolation of molecularly defined LSCs with essential functions in corneal development and repair has important implications for the treatment of corneal disease, particularly corneal blindness due to LSC deficiency.
authors.affiliation: 1] Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye & Ear Infirmary and Harvard Medical School, Boston, Massachusetts 02114, USA [2].
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Ksander
authors.affiliation: 1] Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye & Ear Infirmary and Harvard Medical School, Boston, Massachusetts 02114, USA [2].
authors.forename: Paraskevi E
authors.initials: PE
authors.lastname: Kolovou
authors.affiliation: 1] Transplant Research Program, Division of Nephrology, Boston Children's Hospital, Boston, Massachusetts 02115, USA [2] Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA [3] Department of Medicine, VA Boston Healthcare System, Boston, Massachusetts 02130, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Wilson
authors.affiliation: 1] Transplant Research Program, Division of Nephrology, Boston Children's Hospital, Boston, Massachusetts 02115, USA [2] Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
authors.forename: Karim R
authors.initials: KR
authors.lastname: Saab
authors.affiliation: 1] Department of Medicine, VA Boston Healthcare System, Boston, Massachusetts 02130, USA [2] Transplant Research Program, Division of Nephrology, Boston Children's Hospital, Boston, Massachusetts 02115, USA [3] Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
authors.forename: Qin
authors.initials: Q
authors.lastname: Guo
authors.affiliation: 1] Transplant Research Program, Division of Nephrology, Boston Children's Hospital, Boston, Massachusetts 02115, USA [2] Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye & Ear Infirmary and Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: McGuire
authors.affiliation: Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye & Ear Infirmary and Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Meredith S
authors.initials: MS
authors.lastname: Gregory
authors.affiliation: Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye & Ear Infirmary and Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: William J B
authors.initials: WJ
authors.lastname: Vincent
authors.affiliation: Bascom Palmer Eye Institute and the Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
authors.forename: Victor L
authors.initials: VL
authors.lastname: Perez
authors.affiliation: Bascom Palmer Eye Institute and the Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
authors.forename: Fernando
authors.initials: F
authors.lastname: Cruz-Guilloty
authors.affiliation: Department of Ophthalmology, University of Cincinnati Medical Center, Cincinnati, Ohio 45229, USA.
authors.forename: Winston W Y
authors.initials: WW
authors.lastname: Kao
authors.affiliation: Department of Ophthalmology, University of Cincinnati Medical Center, Cincinnati, Ohio 45229, USA.
authors.forename: Mindy K
authors.initials: MK
authors.lastname: Call
authors.affiliation: Stephen A Wynn Institute for Vision Research, Carver College of Medicine, Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Budd A
authors.initials: BA
authors.lastname: Tucker
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhan
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
authors.forename: George F
authors.initials: GF
authors.lastname: Murphy
authors.affiliation: Department of Ophthalmology, University of Pittsburgh School of Medicine & Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Kira L
authors.initials: KL
authors.lastname: Lathrop
authors.affiliation: Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Clemens
authors.initials: C
authors.lastname: Alt
authors.affiliation: Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Luke J
authors.initials: LJ
authors.lastname: Mortensen
authors.affiliation: Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Charles P
authors.initials: CP
authors.lastname: Lin
authors.affiliation: Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye & Ear Infirmary and Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Zieske
authors.affiliation: 1] Transplant Research Program, Division of Nephrology, Boston Children's Hospital, Boston, Massachusetts 02115, USA [2] Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA [3] Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts 02138, USA [4].
authors.forename: Markus H
authors.initials: MH
authors.lastname: Frank
authors.affiliation: 1] Department of Medicine, VA Boston Healthcare System, Boston, Massachusetts 02130, USA [2] Transplant Research Program, Division of Nephrology, Boston Children's Hospital, Boston, Massachusetts 02115, USA [3] Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts 02138, USA [4] Division of Genetics, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA [5].
authors.forename: Natasha Y
authors.initials: NY
authors.lastname: Frank
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000172:deficiency / Q000378:metabolism*; D018528:ATP-Binding Cassette Transporters / Q000172:deficiency / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D049109:Cell Proliferation; D005260:Female; D006801:Humans; D016850:Limbus Corneae / Q000166:cytology* / Q000502:physiology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D012038:Regeneration; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D014945:Wound Healing
chemical_list: C480744:ABCB5 protein, human; C573563:ABCB5 protein, mouse; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018528:ATP-Binding Cassette Transporters; D015415:Biomarkers; C115051:TP63 protein, human; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins