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Sun D, Zhang X, Chen R, Sang T, Li Y, Wang Q, Xie L, Zhou Q, Dou S. Decoding cellular plasticity and niche regulation of limbal stem cells during corneal wound healing. Stem Cell Res Ther 2024; 15:201. [PMID: 38971839 PMCID: PMC11227725 DOI: 10.1186/s13287-024-03816-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 06/25/2024] [Indexed: 07/08/2024] Open
Abstract
BACKGROUND Dysfunction or deficiency of corneal epithelium results in vision impairment or blindness in severe cases. The rapid and effective regeneration of corneal epithelial cells relies on the limbal stem cells (LSCs). However, the molecular and functional responses of LSCs and their niche cells to injury remain elusive. METHODS Single-cell RNA sequencing was performed on corneal tissues from normal mice and corneal epithelium defect models. Bioinformatics analysis was performed to confirm the distinct characteristics and cell fates of LSCs. Knockdown of Creb5 and OSM treatment experiment were performed to determine their roles of in corneal epithelial wound healing. RESULTS Our data defined the molecular signatures of LSCs and reconstructed the pseudotime trajectory of corneal epithelial cells. Gene network analyses characterized transcriptional landmarks that potentially regulate LSC dynamics, and identified a transcription factor Creb5, that was expressed in LSCs and significantly upregulated after injury. Loss-of-function experiments revealed that silencing Creb5 delayed the corneal epithelial healing and LSC mobilization. Through cell-cell communication analysis, we identified 609 candidate regeneration-associated ligand-receptor interaction pairs between LSCs and distinct niche cells, and discovered a unique subset of Arg1+ macrophages infiltrated after injury, which were present as the source of Oncostatin M (OSM), an IL-6 family cytokine, that were demonstrated to effectively accelerate the corneal epithelial wound healing. CONCLUSIONS This research provides a valuable single-cell resource and reference for the discovery of mechanisms and potential clinical interventions aimed at ocular surface reconstruction.
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Affiliation(s)
- Di Sun
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
| | - Xiaowen Zhang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
| | - Rong Chen
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
| | - Tian Sang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
| | - Ya Li
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
| | - Qun Wang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
| | - Lixin Xie
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China
| | - Qingjun Zhou
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China.
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China.
| | - Shengqian Dou
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China.
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China.
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Badian RA, Lagali N. The inferocentral whorl region and its directional patterns in the corneal sub-basal nerve plexus: A review. Exp Eye Res 2024; 244:109926. [PMID: 38754688 DOI: 10.1016/j.exer.2024.109926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 04/03/2024] [Accepted: 05/12/2024] [Indexed: 05/18/2024]
Abstract
There has been a growing application of in vivo confocal microscopy (IVCM) in the examination of corneal microstructure, including different corneal layers and corneal nerve fibers in health and in pathological conditions. Corneal nerves forming the sub-basal nerve plexus (SBNP) beneath the corneal basal epithelial cell layer in particular have been intensively researched in health and disease as a marker for corneal neurophysioanatomical and degenerative changes. One intriguing feature in the SBNP that is found inferior to the corneal apex, is a whorl-like pattern (or vortex) of nerves, which represents an anatomical landmark. Evidence has indicated that the architecture of this 'whorl region' is dynamic, changing with time in healthy individuals but also in disease conditions such as in diabetic neuropathy and keratoconus. This review summarizes the known information regarding the characteristics and significance of the whorl region of nerves in the corneal SBNP, as a potential area of high relevance for future disease monitoring and diagnostics.
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Affiliation(s)
- Reza A Badian
- Department of Medical Biochemistry, Unit of Regenerative Medicine, Oslo University Hospital, Oslo, Norway.
| | - Neil Lagali
- Department of Ophthalmology, Sørlandet Hospital Arendal, Arendal, Norway; Department of Biomedical and Clinical Sciences, Faculty of Medicine, Linköping University, Linköping, Sweden.
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3
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Verma S, Lin X, Coulson-Thomas VJ. The Potential Reversible Transition between Stem Cells and Transient-Amplifying Cells: The Limbal Epithelial Stem Cell Perspective. Cells 2024; 13:748. [PMID: 38727284 PMCID: PMC11083486 DOI: 10.3390/cells13090748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/18/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024] Open
Abstract
Stem cells (SCs) undergo asymmetric division, producing transit-amplifying cells (TACs) with increased proliferative potential that move into tissues and ultimately differentiate into a specialized cell type. Thus, TACs represent an intermediary state between stem cells and differentiated cells. In the cornea, a population of stem cells resides in the limbal region, named the limbal epithelial stem cells (LESCs). As LESCs proliferate, they generate TACs that move centripetally into the cornea and differentiate into corneal epithelial cells. Upon limbal injury, research suggests a population of progenitor-like cells that exists within the cornea can move centrifugally into the limbus, where they dedifferentiate into LESCs. Herein, we summarize recent advances made in understanding the mechanism that governs the differentiation of LESCs into TACs, and thereafter, into corneal epithelial cells. We also outline the evidence in support of the existence of progenitor-like cells in the cornea and whether TACs could represent a population of cells with progenitor-like capabilities within the cornea. Furthermore, to gain further insights into the dynamics of TACs in the cornea, we outline the most recent findings in other organ systems that support the hypothesis that TACs can dedifferentiate into SCs.
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Affiliation(s)
- Sudhir Verma
- College of Optometry, University of Houston, 4901 Calhoun Road, Houston, TX 77204, USA;
- Deen Dayal Upadhyaya College, University of Delhi, Delhi 110078, India
| | - Xiao Lin
- College of Optometry, University of Houston, 4901 Calhoun Road, Houston, TX 77204, USA;
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Venkatareddy N, Mandal J, Maiti PK. Effect of confinement and topology: 2-TIPS vs. MIPS. SOFT MATTER 2023; 19:8561-8576. [PMID: 37905347 DOI: 10.1039/d3sm00796k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
2-TIPS (two temperature induced phase separation) refers to the phase separation phenomenon observed in mixtures of active and passive particles which are modelled using scalar activity. The active particles are connected to a thermostat at high temperature while the passive particles are connected to the thermostat at low temperature and the relative temperature difference between "hot" and "cold" particles is taken as the measure of the activity χ of the non-equilibrium system. The study of such binary mixtures of hot and cold particles under various kinds of confinement is an important problem in many physical and biological processes. The nature and extent of phase separation are heavily influenced by the geometry of confinement, activity, and density of the non-equilibrium binary mixture. Investigating such 3D binary mixtures confined by parallel walls, we observe that the active and passive particles phase separate, but the extent of phase separation is reduced compared to bulk phase separation at high densities and enhanced at low densities. However, when the binary mixture of active and passive particles is confined inside a spherical cavity, the phase separation is radial for small radii of the confining sphere and the extent of phase separation is higher compared to their bulk counterparts. Confinement leads to interesting properties in the passive (cold) region like enhanced layering and high compression in the direction parallel to the confining wall. In 2D, both the bulk and confined systems of the binary mixture show a significant decrement in the extent of phase separation at higher densities. This observation is attributed to the trapping of active particles inside the passive cluster, which increases with density. Thus the 2D systems show structures more akin to dense-dilute phase co-existence, which is observed in motility induced phase separation in 2D active systems. The binary mixture constrained on the spherical surface also shows similar phase co-existence. Our analyses reveal that the coexistent densities observed in 2-TIPS on the spherical surface agree with the findings of previous studies on MIPS in active systems on a sphere.
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Affiliation(s)
- Nayana Venkatareddy
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
| | - Jaydeep Mandal
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
| | - Prabal K Maiti
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
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5
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Swamynathan SK, Swamynathan S. Corneal epithelial development and homeostasis. Differentiation 2023; 132:4-14. [PMID: 36870804 PMCID: PMC10363238 DOI: 10.1016/j.diff.2023.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/27/2023] [Accepted: 02/20/2023] [Indexed: 03/06/2023]
Abstract
The corneal epithelium (CE), the most anterior cellular structure of the eye, is a self-renewing stratified squamous tissue that protects the rest of the eye from external elements. Each cell in this exquisite three-dimensional structure needs to have proper polarity and positional awareness for the CE to serve as a transparent, refractive, and protective tissue. Recent studies have begun to elucidate the molecular and cellular events involved in the embryonic development, post-natal maturation, and homeostasis of the CE, and how they are regulated by a well-coordinated network of transcription factors. This review summarizes the status of related knowledge and aims to provide insight into the pathophysiology of disorders caused by disruption of CE development, and/or homeostasis.
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Affiliation(s)
| | - Sudha Swamynathan
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
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Pedram O, Jamali R, Abbasian V, Rad VF, Darafsheh A, Khamedi R, Poursaeidi E, Moradi AR. Evaluation of pitting corrosion by dynamic speckle pattern analysis. Sci Rep 2023; 13:8549. [PMID: 37236999 DOI: 10.1038/s41598-023-35559-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 05/20/2023] [Indexed: 05/28/2023] Open
Abstract
There is an increasing interest in non-destructive and real-time high-resolution approaches for corrosion studies in metals. In this paper, we propose the dynamic speckle pattern method as a low-cost, easy-to-implement, and quasi in-situ optical technique for the quantitative evaluation of pitting corrosion. This type of corrosion occurs in a specific area of a metallic structure and causes holes formation leading to structural failure. A Custom 450 stainless steel sample, placed in 3.5 wt% NaCl solution and applied to a [Formula: see text] potential to initiate the corrosion, is used as the sample. The speckle patterns formed by the scattering of a He-Ne laser light is changed over time due to any corrosion in the sample. The analysis of the time-integrate speckle pattern suggests that the growth rate of pitting decreases with time.
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Affiliation(s)
- Omid Pedram
- Department of Mechanical Engineering, University of Zanjan, Zanjan, 45371-38791, Iran
| | - Ramin Jamali
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran
| | - Vahid Abbasian
- Imaging Science Program, McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Vahideh Farzam Rad
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran.
| | - Arash Darafsheh
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Ramin Khamedi
- Department of Mechanical Engineering, University of Zanjan, Zanjan, 45371-38791, Iran
- Department of Mechanical Engineering, School of Engineering & Applied Science, Khazar University, Baku, AZ1096, Azerbaijan
| | - Esmaeil Poursaeidi
- Department of Mechanical Engineering, University of Zanjan, Zanjan, 45371-38791, Iran
| | - Ali-Reza Moradi
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran
- School of Nano Science, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran
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7
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Sun D, Shi WY, Dou SQ. Single-cell RNA sequencing in cornea research: Insights into limbal stem cells and their niche regulation. World J Stem Cells 2023; 15:466-475. [PMID: 37342216 PMCID: PMC10277966 DOI: 10.4252/wjsc.v15.i5.466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/28/2023] [Accepted: 04/17/2023] [Indexed: 05/26/2023] Open
Abstract
The corneal epithelium is composed of stratified squamous epithelial cells on the outer surface of the eye, which acts as a protective barrier and is critical for clear and stable vision. Its continuous renewal or wound healing depends on the proliferation and differentiation of limbal stem cells (LSCs), a cell population that resides at the limbus in a highly regulated niche. Dysfunction of LSCs or their niche can cause limbal stem cell deficiency, a disease that is manifested by failed epithelial wound healing or even blindness. Nevertheless, compared to stem cells in other tissues, little is known about the LSCs and their niche. With the advent of single-cell RNA sequencing, our understanding of LSC characteristics and their microenvironment has grown considerably. In this review, we summarized the current findings from single-cell studies in the field of cornea research and focused on important advancements driven by this technology, including the heterogeneity of the LSC population, novel LSC markers and regulation of the LSC niche, which will provide a reference for clinical issues such as corneal epithelial wound healing, ocular surface reconstruction and interventions for related diseases.
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Affiliation(s)
- Di Sun
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao 266000, Shandong Province, China
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao 266000, Shandong Province, China
| | - Wei-Yun Shi
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao 266000, Shandong Province, China
- Eye Hospital of Shandong First Medical University, Jinan 250000, Shandong Province, China
- School of Ophthalmology, Shandong First Medical University, Qingdao 266000, Shandong Province, China
| | - Sheng-Qian Dou
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao 266000, Shandong Province, China
- Qingdao Eye Hospital of Shandong First Medical University, Qingdao 266000, Shandong Province, China
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8
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Bhattacharya S, Mukherjee A, Pisano S, Dimri S, Knaane E, Altshuler A, Nasser W, Dey S, Shi L, Mizrahi I, Blum N, Jokel O, Amitai-Lange A, Kaganovsky A, Mimouni M, Socea S, Midlij M, Tiosano B, Hasson P, Feral C, Wolfenson H, Shalom-Feuerstein R. The biophysical property of the limbal niche maintains stemness through YAP. Cell Death Differ 2023:10.1038/s41418-023-01156-7. [PMID: 37095157 DOI: 10.1038/s41418-023-01156-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 04/26/2023] Open
Abstract
The cell fate decisions of stem cells (SCs) largely depend on signals from their microenvironment (niche). However, very little is known about how biochemical niche cues control cell behavior in vivo. To address this question, we focused on the corneal epithelial SC model in which the SC niche, known as the limbus, is spatially segregated from the differentiation compartment. We report that the unique biomechanical property of the limbus supports the nuclear localization and function of Yes-associated protein (YAP), a putative mediator of the mechanotransduction pathway. Perturbation of tissue stiffness or YAP activity affects SC function as well as tissue integrity under homeostasis and significantly inhibited the regeneration of the SC population following SC depletion. In vitro experiments revealed that substrates with the rigidity of the corneal differentiation compartment inhibit nuclear YAP localization and induce differentiation, a mechanism that is mediated by the TGFβ-SMAD2/3 pathway. Taken together, these results indicate that SC sense biomechanical niche signals and that manipulation of mechano-sensory machinery or its downstream biochemical output may bear fruits in SC expansion for regenerative therapy.
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Affiliation(s)
- Swarnabh Bhattacharya
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel.
- Department of Medical Oncology and Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.
- Departments of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA.
| | - Abhishek Mukherjee
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Sabrina Pisano
- Université Côte d'Azur, INSERM, CNRS, IRCAN, 06107, Nice, France
| | - Shalini Dimri
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Eman Knaane
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Anna Altshuler
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Waseem Nasser
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Sunanda Dey
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Lidan Shi
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Ido Mizrahi
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Noam Blum
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Ophir Jokel
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Aya Amitai-Lange
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Anna Kaganovsky
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Michael Mimouni
- Department of Ophthalmology, Rambam Health Care Campus, 31096, Haifa, Israel
| | - Sergiu Socea
- Department of Ophthalmology, Rambam Health Care Campus, 31096, Haifa, Israel
| | - Mohamad Midlij
- Department of Ophthalmology, Hilel Yafe Medical Center, Hadera, Israel
| | - Beatrice Tiosano
- Department of Ophthalmology, Hilel Yafe Medical Center, Hadera, Israel
| | - Peleg Hasson
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel
| | - Chloe Feral
- Université Côte d'Azur, INSERM, CNRS, IRCAN, 06107, Nice, France
| | - Haguy Wolfenson
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel.
| | - Ruby Shalom-Feuerstein
- Department of Genetics & Developmental Biology, The Rappaport Faculty of Medicine & Research Institute, Technion Integrated Cancer Center, Technion - Israel Institute of Technology, 31096, Haifa, Israel.
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9
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Raja Noureen S, Owen JP, Mort RL, Yates CA. Swapping in lattice-based cell migration models. Phys Rev E 2023; 107:044402. [PMID: 37198816 DOI: 10.1103/physreve.107.044402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 04/03/2023] [Indexed: 05/19/2023]
Abstract
Cell migration is frequently modeled using on-lattice agent-based models (ABMs) that employ the excluded volume interaction. However, cells are also capable of exhibiting more complex cell-cell interactions, such as adhesion, repulsion, pulling, pushing, and swapping. Although the first four of these have already been incorporated into mathematical models for cell migration, swapping has not been well studied in this context. In this paper, we develop an ABM for cell movement in which an active agent can "swap" its position with another agent in its neighborhood with a given swapping probability. We consider a two-species system for which we derive the corresponding macroscopic model and compare it with the average behavior of the ABM. We see good agreement between the ABM and the macroscopic density. We also analyze the movement of agents at an individual level in the single-species as well as two-species scenarios to quantify the effects of swapping on an agent's motility.
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Affiliation(s)
- Shahzeb Raja Noureen
- Centre for Mathematical Biology, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Jennifer P Owen
- Centre for Mathematical Biology, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Richard L Mort
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Furness Building, Lancaster University, Bailrigg, Lancaster LA1 4YG, United Kingdom
| | - Christian A Yates
- Centre for Mathematical Biology, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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10
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Rajendra D, Mandal J, Hatwalne Y, Maiti PK. Packing and emergence of the ordering of rods in a spherical monolayer. SOFT MATTER 2022; 19:137-146. [PMID: 36477473 DOI: 10.1039/d2sm00799a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Spatially ordered systems confined to surfaces such as spheres exhibit interesting topological structures because of curvature induced frustration in orientational and translational order. The study of these structures is important for investigating the interplay between the geometry, topology, and elasticity, and for their potential applications in materials science, such as engineering directionally binding particles. In this work, we numerically simulate a spherical monolayer of soft repulsive spherocylinders (SRSs) and study the packing of rods and their ordering transition as a function of the packing fraction. In the model that we study, the centers of mass of the spherocylinders (situated at their geometric centers) are constrained to move on a spherical surface. The spherocylinders are free to rotate about any axis that passes through their respective centers of mass. We show that, up to moderate packing fractions, a two dimensional liquid crystalline phase is formed whose orientational ordering increases continuously with increasing density. This monolayer of orientationally ordered SRS particles at medium densities resembles a hedgehog-long axes of the SRS particles are aligned along the local normal to the sphere. At higher packing fractions, the system undergoes a transition to the solid phase, which is riddled with topological point defects (disclinations) and grain boundaries that divide the whole surface into several domains.
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Affiliation(s)
- Dharanish Rajendra
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bengaluru 560012, India.
| | - Jaydeep Mandal
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bengaluru 560012, India.
| | | | - Prabal K Maiti
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bengaluru 560012, India.
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11
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Ikkala K, Raatikainen S, Koivula H, Michon F. Zebrafish cornea formation and homeostasis reveal a slow maturation process, similarly to terrestrial vertebrates' corneas. Front Physiol 2022; 13:906155. [PMID: 36388116 PMCID: PMC9663661 DOI: 10.3389/fphys.2022.906155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 10/14/2022] [Indexed: 01/30/2024] Open
Abstract
Corneal blindness is the fourth leading cause of blindness worldwide. The superficial position of cornea on the eye makes this tissue prone to environmental aggressions, which can have a strong impact on sight. While most corneal pathology studies utilize terrestrial models, the knowledge on zebrafish cornea is too scarce to comprehend its strategy for the maintenance of a clear sight in aquatic environment. In this study, we deciphered the cellular and molecular events during corneal formation and maturation in zebrafish. After describing the morphological changes taking place from 3 days post fertilization (dpf) to adulthood, we analyzed cell proliferation. We showed that label retaining cells appear around 14 to 21dpf. Our cell proliferation study, combined to the study of Pax6a and krtt1c19e expression, demonstrate a long maturation process, ending after 45dpf. This maturation ends with a solid patterning of corneal innervation. Finally, we demonstrated that corneal wounding leads to an intense dedifferentiation, leading to the recapitulation of corneal formation and maturation, via a plasticity period. Altogether, our study deciphers the maturation steps of an aquatic cornea. These findings demonstrate the conservation of corneal formation, maturation and wound healing process in aquatic and terrestrial organisms, and they will enhance the use of zebrafish as model for corneal physiology studies.
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Affiliation(s)
- Kaisa Ikkala
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Sini Raatikainen
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Henri Koivula
- Zebrafish Unit, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Frederic Michon
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Institute for Neurosciences of Montpellier, University Montpellier, INSERM, Montpellier, France
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12
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Sunny SS, Lachova J, Dupacova N, Kozmik Z. Multiple roles of Pax6 in postnatal cornea development. Dev Biol 2022; 491:1-12. [PMID: 36049534 DOI: 10.1016/j.ydbio.2022.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 08/20/2022] [Accepted: 08/23/2022] [Indexed: 11/19/2022]
Abstract
Mammalian corneal development is a multistep process, including formation of the corneal epithelium (CE), endothelium and stroma during embryogenesis, followed by postnatal stratification of the epithelial layers and continuous renewal of the epithelium to replace the outermost corneal cells. Here, we employed the Cre-loxP system to conditionally deplete Pax6 proteins in two domains of ocular cells, i.e., the ocular surface epithelium (cornea, limbus and conjunctiva) (OSE) or postnatal CE via K14-cre or Aldh3-cre, respectively. Earlier and broader inactivation of Pax6 in the OSE resulted in thickened OSE with CE and limbal cells adopting the conjunctival keratin expression pattern. More restricted depletion of Pax6 in postnatal CE resulted in an abnormal cornea marked by reduced epithelial thickness despite increased epithelial cell proliferation. Immunofluorescence studies revealed loss of intermediate filament Cytokeratin 12 and diffused expression of adherens junction components, together with reduced tight junction protein, Zonula occludens-1. Furthermore, the expression of Cytokeratin 14, a basal cell marker in apical layers, indicates impaired differentiation of CE cells. Collectively, our data demonstrate that Pax6 is essential for maintaining proper differentiation and strong intercellular adhesion in postnatal CE cells, whereas limbal Pax6 is required to prevent the outgrowth of conjunctival cells to the cornea.
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Affiliation(s)
- Sweetu Susan Sunny
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, Praha 4, 142 20, Czech Republic
| | - Jitka Lachova
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, Praha 4, 142 20, Czech Republic
| | - Naoko Dupacova
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, Praha 4, 142 20, Czech Republic
| | - Zbynek Kozmik
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, Praha 4, 142 20, Czech Republic.
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13
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Hsu CP, Sciortino A, de la Trobe YA, Bausch AR. Activity-induced polar patterns of filaments gliding on a sphere. Nat Commun 2022; 13:2579. [PMID: 35546549 PMCID: PMC9095588 DOI: 10.1038/s41467-022-30128-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 04/19/2022] [Indexed: 11/16/2022] Open
Abstract
Active matter systems feature the ability to form collective patterns as observed in a plethora of living systems, from schools of fish to swimming bacteria. While many of these systems move in a wide, three-dimensional environment, several biological systems are confined by a curved topology. The role played by a non-Euclidean geometry on the self-organization of active systems is not yet fully understood, and few experimental systems are available to study it. Here, we introduce an experimental setup in which actin filaments glide on the inner surface of a spherical lipid vesicle, thus embedding them in a curved geometry. We show that filaments self-assemble into polar, elongated structures and that, when these match the size of the spherical geometry, both confinement and topological constraints become relevant for the emergent patterns, leading to the formation of polar vortices and jammed states. These results experimentally demonstrate that activity-induced complex patterns can be shaped by spherical confinement and topology.
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Affiliation(s)
- Chiao-Peng Hsu
- Center for Protein Assemblies and Lehrstuhl für Zellbiophysik (E27), Physics Department, Technische Universität München, Garching, Germany
| | - Alfredo Sciortino
- Center for Protein Assemblies and Lehrstuhl für Zellbiophysik (E27), Physics Department, Technische Universität München, Garching, Germany
| | - Yu Alice de la Trobe
- Center for Protein Assemblies and Lehrstuhl für Zellbiophysik (E27), Physics Department, Technische Universität München, Garching, Germany
| | - Andreas R Bausch
- Center for Protein Assemblies and Lehrstuhl für Zellbiophysik (E27), Physics Department, Technische Universität München, Garching, Germany.
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14
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Latta L, Figueiredo FC, Ashery-Padan R, Collinson JM, Daniels J, Ferrari S, Szentmáry N, Solá S, Shalom-Feuerstein R, Lako M, Xapelli S, Aberdam D, Lagali N. Pathophysiology of aniridia-associated keratopathy: Developmental aspects and unanswered questions. Ocul Surf 2021; 22:245-266. [PMID: 34520870 DOI: 10.1016/j.jtos.2021.09.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 07/19/2021] [Accepted: 09/08/2021] [Indexed: 12/13/2022]
Abstract
Aniridia, a rare congenital disease, is often characterized by a progressive, pronounced limbal insufficiency and ocular surface pathology termed aniridia-associated keratopathy (AAK). Due to the characteristics of AAK and its bilateral nature, clinical management is challenging and complicated by the multiple coexisting ocular and systemic morbidities in aniridia. Although it is primarily assumed that AAK originates from a congenital limbal stem cell deficiency, in recent years AAK and its pathogenesis has been questioned in the light of new evidence and a refined understanding of ocular development and the biology of limbal stem cells (LSCs) and their niche. Here, by consolidating and comparing the latest clinical and preclinical evidence, we discuss key unanswered questions regarding ocular developmental aspects crucial to AAK. We also highlight hypotheses on the potential role of LSCs and the ocular surface microenvironment in AAK. The insights thus gained lead to a greater appreciation for the role of developmental and cellular processes in the emergence of AAK. They also highlight areas for future research to enable a deeper understanding of aniridia, and thereby the potential to develop new treatments for this rare but blinding ocular surface disease.
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Affiliation(s)
- L Latta
- Dr. Rolf. M. Schwiete Center for Limbal Stem Cell and Aniridia Research, Saarland University, Homburg, Saar, Germany; Department of Ophthalmology, Saarland University Medical Center, Homburg, Saar, Germany.
| | - F C Figueiredo
- Department of Ophthalmology, Royal Victoria Infirmary, Newcastle Upon Tyne, United Kingdom
| | - R Ashery-Padan
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - J M Collinson
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom
| | - J Daniels
- Cells for Sight, UCL Institute of Ophthalmology, University College London, London, EC1V 9EL, UK
| | - S Ferrari
- The Veneto Eye Bank Foundation, Venice, Italy
| | - N Szentmáry
- Dr. Rolf. M. Schwiete Center for Limbal Stem Cell and Aniridia Research, Saarland University, Homburg, Saar, Germany
| | - S Solá
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - R Shalom-Feuerstein
- Department of Genetics and Developmental Biology, The Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, Haifa, Israel
| | - M Lako
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - S Xapelli
- Instituto Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - D Aberdam
- Centre de Recherche des Cordeliers, INSERM U1138, Team 17, France; Université de Paris, 75006, Paris, France.
| | - N Lagali
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden; Department of Ophthalmology, Sørlandet Hospital Arendal, Arendal, Norway.
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15
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Farrelly O, Suzuki-Horiuchi Y, Brewster M, Kuri P, Huang S, Rice G, Bae H, Xu J, Dentchev T, Lee V, Rompolas P. Two-photon live imaging of single corneal stem cells reveals compartmentalized organization of the limbal niche. Cell Stem Cell 2021; 28:1233-1247.e4. [PMID: 33984283 DOI: 10.1016/j.stem.2021.02.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/18/2020] [Accepted: 02/16/2021] [Indexed: 12/11/2022]
Abstract
The functional heterogeneity of resident stem cells that support adult organs is incompletely understood. Here, we directly visualize the corneal limbus in the eyes of live mice and identify discrete stem cell niche compartments. By recording the life cycle of individual stem cells and their progeny, we directly analyze their fates and show that their location within the tissue can predict their differentiation status. Stem cells in the inner limbus undergo mostly symmetric divisions and are required to sustain the population of transient progenitors that support corneal homeostasis. Using in situ photolabeling, we captured their progeny exiting the niche before moving centripetally in unison. The long-implicated slow-cycling stem cells are functionally distinct and display local clonal dynamics during homeostasis but can contribute to corneal regeneration after injury. This study demonstrates how the compartmentalized organization of functionally diverse stem cell populations supports the maintenance and regeneration of an adult organ.
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Affiliation(s)
- Olivia Farrelly
- Department of Dermatology, Department of Cell and Developmental Biology, Institute for Regenerative Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Yoko Suzuki-Horiuchi
- Department of Dermatology, Department of Cell and Developmental Biology, Institute for Regenerative Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Megan Brewster
- Department of Dermatology, Department of Cell and Developmental Biology, Institute for Regenerative Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Paola Kuri
- Department of Dermatology, Department of Cell and Developmental Biology, Institute for Regenerative Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Sixia Huang
- Department of Dermatology, Department of Cell and Developmental Biology, Institute for Regenerative Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Gabriella Rice
- Department of Dermatology, Department of Cell and Developmental Biology, Institute for Regenerative Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Hyunjin Bae
- Department of Dermatology, Department of Cell and Developmental Biology, Institute for Regenerative Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jianming Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Tzvete Dentchev
- Department of Dermatology, Department of Cell and Developmental Biology, Institute for Regenerative Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Vivian Lee
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Panteleimon Rompolas
- Department of Dermatology, Department of Cell and Developmental Biology, Institute for Regenerative Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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16
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Adil MT, Henry JJ. Understanding cornea epithelial stem cells and stem cell deficiency: Lessons learned using vertebrate model systems. Genesis 2021; 59:e23411. [PMID: 33576188 DOI: 10.1002/dvg.23411] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 12/13/2022]
Abstract
Animal models have contributed greatly to our understanding of human diseases. Here, we focus on cornea epithelial stem cell (CESC) deficiency (commonly called limbal stem cell deficiency, LSCD). Corneal development, homeostasis and wound healing are supported by specific stem cells, that include the CESCs. Damage to or loss of these cells results in blindness and other debilitating ocular conditions. Here we describe the contributions from several vertebrate models toward understanding CESCs and LSCD treatments. These include both mammalian models, as well as two aquatic models, Zebrafish and the amphibian, Xenopus. Pioneering developments have been made using stem cell transplants to restore normal vision in patients with LSCD, but questions still remain about the basic biology of CESCs, including their precise cell lineages and behavior in the cornea. We describe various cell lineage tracing studies to follow their patterns of division, and the fates of their progeny during development, homeostasis, and wound healing. In addition, we present some preliminary results using the Xenopus model system. Ultimately, a more thorough understanding of these cornea cells will advance our knowledge of stem cell biology and lead to better cornea disease therapeutics.
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Affiliation(s)
- Mohd Tayyab Adil
- Department of Cell & Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Jonathan J Henry
- Department of Cell & Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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17
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Hindes J, Edwards V, Kamimoto S, Stantchev G, Schwartz IB. Stability of milling patterns in self-propelled swarms on surfaces. Phys Rev E 2020; 102:022212. [PMID: 32942377 DOI: 10.1103/physreve.102.022212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
In some physical and biological swarms, agents effectively move and interact along curved surfaces. The associated constraints and symmetries can affect collective-motion patterns, but little is known about pattern stability in the presence of surface curvature. To make progress, we construct a general model for self-propelled swarms moving on surfaces using Lagrangian mechanics. We find that the combination of self-propulsion, friction, mutual attraction, and surface curvature produce milling patterns where each agent in a swarm oscillates on a limit cycle with different agents splayed along the cycle such that the swarm's center-of-mass remains stationary. In general, such patterns loose stability when mutual attraction is insufficient to overcome the constraint of curvature, and we uncover two broad classes of stationary milling-state bifurcations. In the first, a spatially periodic mode undergoes a Hopf bifurcation as curvature is increased, which results in unstable spatiotemporal oscillations. This generic bifurcation is analyzed for the sphere and demonstrated numerically for several surfaces. In the second, a saddle-node-of-periodic orbits occurs in which stable and unstable milling states collide and annihilate. The latter is analyzed for milling states on cylindrical surfaces. Our results contribute to the general understanding of swarm pattern formation and stability in the presence of surface curvature and may aid in designing robotic swarms that can be controlled to move over complex surfaces and terrains.
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Affiliation(s)
- Jason Hindes
- U.S. Naval Research Laboratory, Washington, D.C. 20375, USA
| | | | - Sayomi Kamimoto
- Department of Mathematics, George Mason University, Fairfax, Virginia 22030, USA
| | | | - Ira B Schwartz
- U.S. Naval Research Laboratory, Washington, D.C. 20375, USA
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18
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Sunny SS, Lachova J, Dupacova N, Zitova A, Kozmik Z. Generation and characterization of Aldh3-Cre transgenic mice as a tool for conditional gene deletion in postnatal cornea. Sci Rep 2020; 10:9083. [PMID: 32493941 PMCID: PMC7270111 DOI: 10.1038/s41598-020-65878-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/12/2020] [Indexed: 11/18/2022] Open
Abstract
Conditional gene targeting in mice by means of Cre-loxP strategy represents a powerful approach to study mammalian gene function. This approach is however dependent on the availability of suitable strains of mice with a tissue or time restricted activity of the Cre recombinase. Here we describe Aldh3-Cre transgenic mice as a useful tool to conditionally delete genes in cornea, a specialized transparent tissue found on the anterior-most part of the eye, which acts as a protective barrier and contributes to the refractive power. Using a set of floxed alleles we demonstrate high Aldh3-Cre activity in corneal epithelial cells, corneal stroma and conjunctival epithelial cells at postnatal stages. Aldh3-Cre will thus be particularly beneficial for functional analysis of genes which are vital for postnatal development of cornea and conjunctiva.
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Affiliation(s)
- Sweetu Susan Sunny
- Laboratory of Eye Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Division BIOCEV, Prumyslova 595, 252 50, Vestec, Czech Republic
| | - Jitka Lachova
- Laboratory of Eye Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Division BIOCEV, Prumyslova 595, 252 50, Vestec, Czech Republic
| | - Naoko Dupacova
- Laboratory of Eye Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Division BIOCEV, Prumyslova 595, 252 50, Vestec, Czech Republic
| | - Anna Zitova
- Laboratory of Eye Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Division BIOCEV, Prumyslova 595, 252 50, Vestec, Czech Republic.,Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, Praha 4, 142 20, Czech Republic
| | - Zbynek Kozmik
- Laboratory of Eye Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Division BIOCEV, Prumyslova 595, 252 50, Vestec, Czech Republic. .,Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, Praha 4, 142 20, Czech Republic.
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19
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Henkes S, Kostanjevec K, Collinson JM, Sknepnek R, Bertin E. Dense active matter model of motion patterns in confluent cell monolayers. Nat Commun 2020; 11:1405. [PMID: 32179745 PMCID: PMC7075903 DOI: 10.1038/s41467-020-15164-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 02/07/2020] [Indexed: 11/09/2022] Open
Abstract
Epithelial cell monolayers show remarkable displacement and velocity correlations over distances of ten or more cell sizes that are reminiscent of supercooled liquids and active nematics. We show that many observed features can be described within the framework of dense active matter, and argue that persistent uncoordinated cell motility coupled to the collective elastic modes of the cell sheet is sufficient to produce swirl-like correlations. We obtain this result using both continuum active linear elasticity and a normal modes formalism, and validate analytical predictions with numerical simulations of two agent-based cell models, soft elastic particles and the self-propelled Voronoi model together with in-vitro experiments of confluent corneal epithelial cell sheets. Simulations and normal mode analysis perfectly match when tissue-level reorganisation occurs on times longer than the persistence time of cell motility. Our analytical model quantitatively matches measured velocity correlation functions over more than a decade with a single fitting parameter.
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Affiliation(s)
- Silke Henkes
- School of Mathematics, University of Bristol, Bristol, BS8 1TW, United Kingdom.
- Institute of Complex Systems and Mathematical Biology, University of Aberdeen, Aberdeen, AB24 3UE, United Kingdom.
| | - Kaja Kostanjevec
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, AB25 2ZD, United Kingdom
| | - J Martin Collinson
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, AB25 2ZD, United Kingdom
| | - Rastko Sknepnek
- School of Science and Engineering, University of Dundee, Dundee, DD1 4HN, United Kingdom.
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, United Kingdom.
| | - Eric Bertin
- Université Grenoble Alpes and CNRS, LIPHY, F-38000, Grenoble, France.
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20
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Kaplan N, Wang J, Wray B, Patel P, Yang W, Peng H, Lavker RM. Single-Cell RNA Transcriptome Helps Define the Limbal/Corneal Epithelial Stem/Early Transit Amplifying Cells and How Autophagy Affects This Population. Invest Ophthalmol Vis Sci 2019; 60:3570-3583. [PMID: 31419300 PMCID: PMC6701873 DOI: 10.1167/iovs.19-27656] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose Single-cell RNA-sequencing (scRNA-seq) was used to interrogate the relatively rare stem (SC) and early transit amplifying (TA) cell populations in limbal/corneal epithelia from wild-type and autophagy-compromised mice. Methods We conducted scRNA-seq on ocular anterior segmental tissue from wild-type and beclin 1–deficient (beclin1+/−) mice, using a 10X Gemomics pipeline. Cell populations were distinguished by t-distributed stochastic neighbor embedding. Seurat analysis was conducted to compare gene expression profiles between these two groups of mice. Differential protein expression patterns were validated by immunofluorescence staining and immunoblotting. Results Unbiased clustering detected 10 distinct populations: three clusters of mesenchymal and seven clusters of epithelial cells, based on their unique molecular signatures. A discrete group of mesenchymal cells expressed genes associated with corneal stromal SCs. We identified three limbal/corneal epithelial cell subpopulations designated as stem/early TA, mature TA, and differentiated corneal epithelial cells. Thioredoxin-interacting protein and PDZ-binding kinase (PBK) were identified as novel regulators of stem/early TA cell quiescence. PBK arrested corneal epithelial cells in G2/M phase of the cell cycle. Beclin1+/− mice displayed a decrease in proliferation-associated (Ki67, Lrig1) and stress-response (H2ax) genes. The most increased gene in beclin1+/− mice was transcription factor ATF3, which negatively regulates limbal epithelial cell proliferation. Conclusions Establishment of a comprehensive atlas of genes expressed by stromal and epithelial cells from limbus and cornea forms the foundation for unraveling regulatory networks among these distinct tissues. Similarly, scRNA-seq profiling of the anterior segmental epithelia from wild-type and autophagy-deficient mice provides new insights into how autophagy influences proliferation in these tissues.
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Affiliation(s)
- Nihal Kaplan
- Department of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Junyi Wang
- Department of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States.,Department of Ophthalmology, Ophthalmology and Visual Science Key Lab of PLA, Chinese PLA General Hospital, Beijing, China
| | - Brian Wray
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Priyam Patel
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Wending Yang
- Department of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Han Peng
- Department of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Robert M Lavker
- Department of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
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21
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Marfurt C, Anokwute MC, Fetcko K, Mahony-Perez E, Farooq H, Ross E, Baumanis MM, Weinberg RL, McCarron ME, Mankowski JL. Comparative Anatomy of the Mammalian Corneal Subbasal Nerve Plexus. Invest Ophthalmol Vis Sci 2019; 60:4972-4984. [PMID: 31790560 PMCID: PMC6886725 DOI: 10.1167/iovs.19-28519] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 10/24/2019] [Indexed: 12/20/2022] Open
Abstract
Purpose The subbasal nerve plexus (SNP) is the densest and most recognizable component of the mammalian corneal innervation; however, the anatomical configuration of the SNP in most animal models remains incompletely described. The purpose of the current study is to describe in detail the SNP architecture in eight different mammals, including several popular animal models used in cornea research. Methods Corneal nerves in mouse, rat, guinea pig, rabbit, dog, macaque, domestic pig, and cow eyes were stained immunohistochemically with antiserum directed against neurotubulin. SNP architecture was documented by digital photomicrography and large-scale reconstructions, that is, corneal nerve maps, using a drawing tube attached to a light microscope. Results Subbasal nerve fibers (SNFs) in mice, rats, guinea pigs, dogs, and macaques radiated centrally from the corneoscleral limbus toward the corneal apex in a whorl-like or spiraling pattern. SNFs in rabbit and bovine corneas swept horizontally across the ocular surface in a temporal-to-nasal direction and converged on the inferonasal limbus without forming a spiral. SNFs in the pig cornea radiated centrifugally in all directions, like a starburst, from a focal point located equidistant between the corneal apex and the superior pole. Conclusions The results of the present study have demonstrated for the first time substantial interspecies differences in the architectural organization of the mammalian SNP. The physiological significance of these different patterns and the mechanisms that regulate SNP pattern formation in the mammalian cornea remain incompletely understood and warrant additional investigation.
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Affiliation(s)
- Carl Marfurt
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Miracle C. Anokwute
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Kaleigh Fetcko
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Erin Mahony-Perez
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Hassan Farooq
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Emily Ross
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Maraya M. Baumanis
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Rachel L. Weinberg
- Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Megan E. McCarron
- Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Joseph L. Mankowski
- Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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22
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Adil MT, Simons CM, Sonam S, Henry JJ. Understanding cornea homeostasis and wound healing using a novel model of stem cell deficiency in Xenopus. Exp Eye Res 2019; 187:107767. [PMID: 31437439 DOI: 10.1016/j.exer.2019.107767] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 07/25/2019] [Accepted: 08/16/2019] [Indexed: 12/13/2022]
Abstract
Limbal Stem Cell Deficiency (LSCD) is a painful and debilitating disease that results from damage or loss of the Corneal Epithelial Stem Cells (CESCs). Therapies have been developed to treat LSCD by utilizing epithelial stem cell transplants. However, effective repair and recovery depends on many factors, such as the source and concentration of donor stem cells, and the proper conditions to support these transplanted cells. We do not yet fully understand how CESCs heal wounds or how transplanted CESCs are able to restore transparency in LSCD patients. A major hurdle has been the lack of vertebrate models to study CESCs. Here we utilized a short treatment with Psoralen AMT (a DNA cross-linker), immediately followed by UV treatment (PUV treatment), to establish a novel frog model that recapitulates the characteristics of cornea stem cell deficiency, such as pigment cell invasion from the periphery, corneal opacity, and neovascularization. These PUV treated whole corneas do not regain transparency. Moreover, PUV treatment leads to appearance of the Tcf7l2 labeled subset of apical skin cells in the cornea region. PUV treatment also results in increased cell death, immediately following treatment, with pyknosis as a primary mechanism. Furthermore, we show that PUV treatment causes depletion of p63 expressing basal epithelial cells, and can stimulate mitosis in the remaining cells in the cornea region. To study the response of CESCs, we created localized PUV damage by focusing the UV radiation on one half of the cornea. These cases initially develop localized stem cell deficiency characteristics on the treated side. The localized PUV treatment is also capable of stimulating some mitosis in the untreated (control) half of those corneas. Unlike the whole treated corneas, the treated half is ultimately able to recover and corneal transparency is restored. Our study provides insight into the response of cornea cells following stem cell depletion, and establishes Xenopus as a suitable model for studying CESCs, stem cell deficiency, and other cornea diseases. This model will also be valuable for understanding the nature of transplanted CESCs, which will lead to progress in the development of therapeutics for LSCD.
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Affiliation(s)
- Mohd Tayyab Adil
- Department of Cell & Developmental Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave. Urbana, IL, 61801, USA.
| | - Claire M Simons
- Department of Cell & Developmental Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave. Urbana, IL, 61801, USA.
| | - Surabhi Sonam
- Department of Cell & Developmental Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave. Urbana, IL, 61801, USA.
| | - Jonathan J Henry
- Department of Cell & Developmental Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave. Urbana, IL, 61801, USA.
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Sonam S, Srnak JA, Perry KJ, Henry JJ. Molecular markers for corneal epithelial cells in larval vs. adult Xenopus frogs. Exp Eye Res 2019; 184:107-125. [PMID: 30981716 DOI: 10.1016/j.exer.2019.04.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 04/08/2019] [Indexed: 12/14/2022]
Abstract
Corneal Epithelial Stem Cells (CESCs) and their proliferative progeny, the Transit Amplifying Cells (TACs), are responsible for maintaining the integrity and transparency of the cornea. These stem cells (SCs) are widely used in corneal transplants and ocular surface reconstruction. Molecular markers are essential to identify, isolate and enrich for these cells, yet no definitive CESC marker has been established. An extensive literature survey shows variability in the expression of putative CESC markers among vertebrates; being attributed to species-specific variations, or other differences in developmental stages of these animals, approaches used in these studies and marker specificity. Here, we expanded the search for CESC markers using the amphibian model Xenopus laevis. In previous studies we found that long-term label retaining cells (suggestive of CESCs and TACs) are present throughout the larval basal corneal epithelium. In adult frogs, these cells become concentrated in the peripheral cornea (limbal region). Here, we used immunofluorescence to characterize the expression of nine proteins in the corneas of both Xenopus larvae and adults (post-metamorphic). We found that localization of some markers change between larval and adult stages. Markers such as p63, Keratin 19, and β1-integrin are restricted to basal corneal epithelial cells of the larvae. After metamorphosis their expression is found in basal and intermediate layer cells of the adult frog corneal epithelium. Another protein, Pax6 was expressed in the larval corneas, but surprisingly it was not detected in the adult corneal epithelium. For the first time we report that Tcf7l2 can be used as a marker to differentiate cornea vs. skin in frogs. Tcf7l2 is present only in the frog skin, which differs from reports indicating that the protein is expressed in the human cornea. Furthermore, we identified the transition between the inner, and the outer surface of the adult frog eyelid as a key boundary in terms of marker expression. Although these markers are useful to identify different regions and cellular layers of the frog corneal epithelium, none is unique to CESCs or TACs. Our results confirm that there is no single conserved CESC marker in vertebrates. This molecular characterization of the Xenopus cornea facilitates its use as a vertebrate model to understand the functions of key proteins in corneal homeostasis and wound repair.
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Affiliation(s)
- Surabhi Sonam
- Department of Cell and Developmental Biology, University of Illinois, 601 S. Goodwin Avenue, Urbana, IL, 61801, USA
| | - Jennifer A Srnak
- Department of Cell and Developmental Biology, University of Illinois, 601 S. Goodwin Avenue, Urbana, IL, 61801, USA
| | - Kimberly J Perry
- Department of Cell and Developmental Biology, University of Illinois, 601 S. Goodwin Avenue, Urbana, IL, 61801, USA
| | - Jonathan J Henry
- Department of Cell and Developmental Biology, University of Illinois, 601 S. Goodwin Avenue, Urbana, IL, 61801, USA.
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24
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Panzica DA, Findlay AS, van Ladesteijn R, Collinson JM. The core planar cell polarity gene, Vangl2, maintains apical-basal organisation of the corneal epithelium. J Anat 2019; 234:106-119. [PMID: 28833131 PMCID: PMC6284432 DOI: 10.1111/joa.12676] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2017] [Indexed: 12/23/2022] Open
Abstract
The role of the core planar cell polarity (PCP) pathway protein, Vangl2, was investigated in the corneal epithelium of the mammalian eye, a paradigm anatomical model of planar cell migration. The gene was conditionally knocked out in vivo and knocked down by siRNA, followed by immunohistochemical, behavioural and morphological analysis of corneal epithelial cells. The primary defects observed in vivo were of apical-basal organisation of the corneal epithelium, with abnormal stratification throughout life, mislocalisation of the cell membrane protein, Scribble, to the basal side of cells, and partial loss of the epithelial basement membrane. Planar defects in migration after wounding and in the presence of an applied electric field were noted. However, knockdown of Vangl2 also retarded cell migration in individual cells that had no contact with their neighbours, which precluded a classic PCP mechanism. It is concluded that some of the planar polarity phenotypes in PCP mutants may arise from disruption of apical-basal polarity.
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Affiliation(s)
- D. Alessio Panzica
- School of MedicineMedical Sciences and NutritionUniversity of AberdeenAberdeenUK
| | - Amy S. Findlay
- School of MedicineMedical Sciences and NutritionUniversity of AberdeenAberdeenUK
| | | | - J. Martin Collinson
- School of MedicineMedical Sciences and NutritionUniversity of AberdeenAberdeenUK
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25
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Sagga N, Kuffová L, Vargesson N, Erskine L, Collinson JM. Limbal epithelial stem cell activity and corneal epithelial cell cycle parameters in adult and aging mice. Stem Cell Res 2018; 33:185-198. [PMID: 30439642 PMCID: PMC6288239 DOI: 10.1016/j.scr.2018.11.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/04/2018] [Accepted: 11/04/2018] [Indexed: 12/15/2022] Open
Abstract
Limbal epithelial stem cells (LESCs) are believed to be responsible for corneal epithelial maintenance and repair after injury, but their activity has never been properly quantified in aging or wounded eyes. In this study, labelling with thymidine analogues, 5-iodo-2′-deoxyuridine (IdU), 5-chloro-2′-deoxyuridine (CldU) and 5-ethynyl-2′-deoxyuridine (EdU), was used to estimate cell-cycle time of the corneal and limbal epithelia in wild-type eyes, comparing aging (12 months) and young adult (8 week) mice. In C57BL/6 mice, cells cycled significantly faster in the central corneal epithelium of aging eyes (3.24 ± 0.2 days) compared to 10 week old mice (4.97 ± 0.5 days). Long-term labelling with IdU was used to detect slow-cycling stem cells, followed by CldU or EdU labelling to quantify the proliferative dynamics of LESCs during corneal wound healing. In unwounded eyes, 4.52 ± 1.4% of LESCs were shown to enter S phase in a 24 h period and were estimated to divide every 2–3 weeks. Within 24 h of corneal injury this rose significantly to 32.8 ± 10.0% of stem cells indicating a seven-fold increase in activation. In contrast, no comparable increase in LESC activation was observed in aging mice after wounding. In the 24–48 h period after wounding in young adults, LESC activation continued to increase (86.5 ± 8.2% of label-retaining cells in wounded eye were in S-phase) but surprisingly, 46.0 ± 9.4% of LESCs were observed to reenter S-phase in the contralateral unwounded eye. These data imply an unsuspected systemic effect of corneal wounding on LESC activation suggesting that injury to one eye elicits a regenerative response in both. Corneal wounding causes a seven-fold increase in the number of limbal epithelial stem cells in mitosis, 24 h after injury. This stem cell response to injury does not occur in aging animals. 24–48 h after wounding, nearly 90% of limbal epithelial stem cells are in mitosis. Wounding to one cornea elicits a systemic stem cell response in the other cornea after 24 h.
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Affiliation(s)
- Nada Sagga
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Lucia Kuffová
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom; Department of Ophthalmology, NHS Grampian, Aberdeen, UK
| | - Neil Vargesson
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Lynda Erskine
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - J Martin Collinson
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom.
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26
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Basche M, Kampik D, Kawasaki S, Branch MJ, Robinson M, Larkin DF, Smith AJ, Ali RR. Sustained and Widespread Gene Delivery to the Corneal Epithelium via In Situ Transduction of Limbal Epithelial Stem Cells, Using Lentiviral and Adeno-Associated Viral Vectors. Hum Gene Ther 2018; 29:1140-1152. [PMID: 30070149 DOI: 10.1089/hum.2018.115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Corneal epithelial dystrophies are typically characterized by symptoms such as pain, light sensitivity, and corneal opacification leading to impaired vision. The development of gene therapy for such conditions has been hindered by an inability to achieve sustained and extensive gene transfer, as the epithelium is highly replicative and has evolved to exclude foreign material. We undertook a comprehensive study in mice aiming to overcome these impediments. Direct injection of lentiviral vector within the stem cell niche resulted in centripetal streaks of epithelial transgene expression sustained for >1 year, indicating limbal epithelial stem cell transduction in situ. The extent of transgene expression varied markedly but at maximum covered 26% of the corneal surface. After intrastromal injection, adeno-associated viral (AAV) vectors were found to penetrate Bowman's membrane and mediate widespread, but transient (12-16 days), epithelial transgene expression. This was sufficient, when applied within a Cre/lox system, to result in recombined epithelium covering up to approximately 80% of the corneal surface. Lastly, systemic delivery of AAV2/9 in neonatal mice resulted in extensive corneal transduction, despite the relative avascularity of the tissue. These findings provide the foundations of a gene therapy toolkit for the corneal epithelium, which might be applied to correction of inherited epithelial dystrophies.
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Affiliation(s)
- Mark Basche
- 1 Department of Genetics, UCL Institute of Ophthalmology, London, United Kingdom; London, United Kingdom
| | - Daniel Kampik
- 1 Department of Genetics, UCL Institute of Ophthalmology, London, United Kingdom; London, United Kingdom
| | - Satoshi Kawasaki
- 2 Department of Ophthalmology, Kyoto Prefectural University of Medicine , Kyoto, Japan
| | - Matthew J Branch
- 1 Department of Genetics, UCL Institute of Ophthalmology, London, United Kingdom; London, United Kingdom
| | - Martha Robinson
- 1 Department of Genetics, UCL Institute of Ophthalmology, London, United Kingdom; London, United Kingdom
| | | | - Alexander J Smith
- 1 Department of Genetics, UCL Institute of Ophthalmology, London, United Kingdom; London, United Kingdom
| | - Robin R Ali
- 1 Department of Genetics, UCL Institute of Ophthalmology, London, United Kingdom; London, United Kingdom
- 4 NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
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27
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West JD, Mort RL, Hill RE, Morley SD, Collinson JM. Computer simulation of neutral drift among limbal epithelial stem cells of mosaic mice. Stem Cell Res 2018; 30:1-11. [PMID: 29777801 PMCID: PMC6049397 DOI: 10.1016/j.scr.2018.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 05/08/2018] [Accepted: 05/10/2018] [Indexed: 02/08/2023] Open
Abstract
The use of mice that are mosaic for reporter gene expression underlies many lineage-tracing studies in stem cell biology. For example, using mosaic LacZ reporter mice, it was shown that limbal epithelial stem cells (LESCs) around the periphery of the cornea maintain radial sectors of the corneal epithelium and that radial stripe numbers declined with age. Originally, the corneal results were interpreted as progressive, age-related loss or irreversible inactivation of some LESC clones. In this study we used computer simulations to show that these results could also be explained by stochastic replacement of LESCs by neighbouring LESCs, leading to neutral drift of LESC populations. This was shown to reduce the number of coherent clones of LESCs and hence would coarsen the mosaic pattern in the corneal epithelium without reducing the absolute number of LESCs. Simulations also showed that corrected stripe numbers declined more slowly when LESCs were grouped non-randomly and that mosaicism was rarely lost unless simulated LESC numbers were unrealistically low. Possible reasons why age-related changes differ between mosaic corneal epithelia and other systems, such as adrenal cortices and intestinal crypts, are discussed. Age-related reduction of corneal stripes in mosaic mice was simulated. Stem cell loss and/or stem cell replacement reduced simulated stripe numbers. Stem cell replacement, without reducing stem cell numbers, caused neutral drift. Clumping of stem cells into larger groups caused slower decline in stripe numbers. Replacement rarely caused loss of mosaicism unless there were few stem cells.
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Affiliation(s)
- John D West
- Centre for Integrative Physiology, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK.
| | - Richard L Mort
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Bailrigg, Lancaster LA1 4YG, UK
| | - Robert E Hill
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Steven D Morley
- Division of Health Sciences, University of Edinburgh Medical School, Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - J Martin Collinson
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
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28
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Henkes S, Marchetti MC, Sknepnek R. Dynamical patterns in nematic active matter on a sphere. Phys Rev E 2018; 97:042605. [PMID: 29758687 DOI: 10.1103/physreve.97.042605] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Indexed: 01/24/2023]
Abstract
Using simulations of self-propelled agents with short-range repulsion and nematic alignment, we explore the dynamical phases of a dense active nematic confined to the surface of a sphere. We map the nonequilibrium phase diagram as a function of curvature, alignment strength, and activity. Our model reproduces several phases seen in recent experiments on active microtubule bundles confined the surfaces of vesicles. At low driving, we recover the equilibrium nematic ground state with four +1/2 defects. As the driving is increased, geodesic forces drive the transition to a polar band wrapping around an equator, with large empty spherical caps corresponding to two +1 defects at the poles. Upon further increasing activity, the bands fold onto themselves, and the system eventually transitions to a turbulent state marked by the proliferation of pairs of topological defects. We highlight the key role of the nematic persistence length in controlling pattern formation in these confined systems with positive Gaussian curvature.
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Affiliation(s)
- Silke Henkes
- Institute for Complex Systems and Mathematical Biology, Department of Physics, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - M Cristina Marchetti
- Department of Physics and Soft Matter Program, Syracuse University, Syracuse, New York 13244, USA
| | - Rastko Sknepnek
- School of Sciences and Engineering and School of Life Sciences, University of Dundee, Dundee DD1 4HN, United Kingdom
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29
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Kim S, Thomasy SM, Ramsey D, Zhao M, Mannis MJ, Murphy CJ. Whorl pattern keratopathies in veterinary and human patients. Vet Ophthalmol 2018; 21:661-667. [DOI: 10.1111/vop.12552] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Soohyun Kim
- Department of Surgical and Radiological Sciences; School of Veterinary Medicine; University of California Davis; Davis CA USA
| | - Sara M. Thomasy
- Department of Surgical and Radiological Sciences; School of Veterinary Medicine; University of California Davis; Davis CA USA
- Department of Ophthalmology & Vision Science; School of Medicine; University of California Davis; Davis CA USA
| | - David Ramsey
- The Animal Ophthalmology Center; Williamston MI USA
| | - Min Zhao
- Department of Ophthalmology & Vision Science; School of Medicine; University of California Davis; Davis CA USA
- Department of Dermatology; School of Medicine; University of California Davis; Davis CA USA
| | - Mark J. Mannis
- Department of Ophthalmology & Vision Science; School of Medicine; University of California Davis; Davis CA USA
| | - Christopher J. Murphy
- Department of Surgical and Radiological Sciences; School of Veterinary Medicine; University of California Davis; Davis CA USA
- Department of Ophthalmology & Vision Science; School of Medicine; University of California Davis; Davis CA USA
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30
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Kalha S, Shrestha B, Sanz Navarro M, Jones KB, Klein OD, Michon F. Bmi1+ Progenitor Cell Dynamics in Murine Cornea During Homeostasis and Wound Healing. Stem Cells 2018; 36:562-573. [PMID: 29282831 DOI: 10.1002/stem.2767] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 11/27/2017] [Accepted: 12/09/2017] [Indexed: 01/06/2023]
Abstract
The outermost layer of the eye, the cornea, is renewed continuously throughout life. Stem cells of the corneal epithelium reside in the limbus at the corneal periphery and ensure homeostasis of the central epithelium. However, in young mice, homeostasis relies on cells located in the basal layer of the central corneal epithelium. Here, we first studied corneal growth during the transition from newborn to adult and assessed Keratin 19 (Krt19) expression as a hallmark of corneal maturation. Next, we set out to identify a novel marker of murine corneal epithelial progenitor cells before, during and after maturation, and we found that Bmi1 is expressed in the basal epithelium of the central cornea and limbus. Furthermore, we demonstrated that Bmi1+ cells participated in tissue replenishment in the central cornea. These Bmi1+ cells did not maintain homeostasis of the cornea for more than 3 months, reflecting their status as progenitor rather than stem cells. Finally, after injury, Bmi1+ cells fueled homeostatic maintenance, whereas wound closure occurred via epithelial reorganization. Stem Cells 2018;36:562-573.
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Affiliation(s)
- Solja Kalha
- Helsinki Institute of Life Science, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Bideep Shrestha
- Helsinki Institute of Life Science, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Maria Sanz Navarro
- Helsinki Institute of Life Science, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Kyle B Jones
- Department of Orofacial Sciences and Program in Craniofacial Biology, University of California San Francisco, San Francisco, California, USA
| | - Ophir D Klein
- Department of Orofacial Sciences and Program in Craniofacial Biology, University of California San Francisco, San Francisco, California, USA.,Department of Pediatrics and Institute for Human Genetics, University of California San Francisco, San Francisco, California, USA
| | - Frederic Michon
- Helsinki Institute of Life Science, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,Keele Medical School and Institute for Science and Technology in Medicine, Keele University, Keele, Staffordshire, England, United Kingdom
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31
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Richardson A, Lobo EP, Delic NC, Myerscough MR, Lyons JG, Wakefield D, Di Girolamo N. Keratin-14-Positive Precursor Cells Spawn a Population of Migratory Corneal Epithelia that Maintain Tissue Mass throughout Life. Stem Cell Reports 2017; 9:1081-1096. [PMID: 28943255 PMCID: PMC5639292 DOI: 10.1016/j.stemcr.2017.08.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/23/2017] [Accepted: 08/23/2017] [Indexed: 01/19/2023] Open
Abstract
The dynamics of epithelial stem cells (SCs) that contribute to the formation and maintenance of the cornea are poorly understood. Here, we used K14CreERT2-Confetti (Confetti) mice, sophisticated imaging, and computational modeling to trace the origins and fate of these cells during embryogenesis and adult life. We show that keratin-14 (K14+)-expressing progenitors are defined and widely distributed across the E16.5 cornea, after which they undergo cycles of proliferation and dispersal prior to eyelid opening. K14+ clonal patches disappear from the central cornea and are replaced by limbal-derived K14+ streaks, a finding that aligned with bromodeoxyuridine label-retaining studies. We also elucidated the mechanism by which SC clones are lost during life and propose this is due to population asymmetry and neutral drift. Finally, we established that the occurrence of an equatorial migratory mid-line is a consequence of apoptosis in a narrow nasal-temporal region, the site where eyelids meet during blinking. Embryonic K14+-progenitor-derived clonal expansion is biphasic Limbal, not central, epithelial stem cells replenish the corneal epithelium Age-related LESC dynamics are consistent with population asymmetric neutral drift Normal clonal migration patterns are altered by central corneal apoptosis
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Affiliation(s)
- Alexander Richardson
- School of Medical Science, University of New South Wales, Sydney, NSW 2052, Australia
| | - Erwin P Lobo
- School of Mathematics and Statistics, University of Sydney, Sydney, NSW 2050, Australia
| | - Naomi C Delic
- Immune Imaging Program, Centenary Institute, Sydney, NSW 2050, Australia; Department of Dermatology, Sydney Medical School, University of Sydney, Sydney, NSW 2050, Australia
| | - Mary R Myerscough
- School of Mathematics and Statistics, University of Sydney, Sydney, NSW 2050, Australia
| | - J Guy Lyons
- Immune Imaging Program, Centenary Institute, Sydney, NSW 2050, Australia; Department of Dermatology, Sydney Medical School, University of Sydney, Sydney, NSW 2050, Australia; Cancer Services, Royal Prince Alfred Hospital, Sydney, NSW 2050, Australia
| | - Denis Wakefield
- School of Medical Science, University of New South Wales, Sydney, NSW 2052, Australia
| | - Nick Di Girolamo
- School of Medical Science, University of New South Wales, Sydney, NSW 2052, Australia.
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32
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Abstract
Like meridian lines on a globe, two lines on a Gaussian-curved surface cannot be simultaneously straight and parallel everywhere. We find that this inescapable property of Gaussian curvature has important consequences for the clustering and swarming behavior of active matter. Focusing on the case of self-propelled particles confined to the surface of a sphere, we find that for high curvature, particles converge to a common orbit to form symmetry-breaking microswarms. We prove that this microswarm flocking behavior is distinct from other known examples in that it is a result of the curvature, and not incorporated through Vicsek-like alignment rules or collision-induced torques. Additionally, we find that clustering can be either enhanced or hindered as a consequence of both the microswarming behavior and curvature-induced changes to the shape of a cluster's boundary. Furthermore, we demonstrate how surfaces of non-constant curvature lead to behaviors that are not explained by the simple averaging of the total curvature. These observations demonstrate a promising method for engineering the emergent behavior of active matter via the geometry of the environment.
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Affiliation(s)
- Isaac R Bruss
- Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
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33
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Janssen LMC, Kaiser A, Löwen H. Aging and rejuvenation of active matter under topological constraints. Sci Rep 2017; 7:5667. [PMID: 28720777 PMCID: PMC5516002 DOI: 10.1038/s41598-017-05569-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 05/30/2017] [Indexed: 12/15/2022] Open
Abstract
The coupling of active, self-motile particles to topological constraints can give rise to novel non-equilibrium dynamical patterns that lack any passive counterpart. Here we study the behavior of self-propelled rods confined to a compact spherical manifold by means of Brownian dynamics simulations. We establish the state diagram and find that short active rods at sufficiently high density exhibit a glass transition toward a disordered state characterized by persistent self-spinning motion. By periodically melting and revitrifying the spherical spinning glass, we observe clear signatures of time-dependent aging and rejuvenation physics. We quantify the crucial role of activity in these non-equilibrium processes, and rationalize the aging dynamics in terms of an absorbing-state transition toward a more stable active glassy state. Our results demonstrate both how concepts of passive glass phenomenology can carry over into the realm of active matter, and how topology can enrich the collective spatiotemporal dynamics in inherently non-equilibrium systems.
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Affiliation(s)
- Liesbeth M C Janssen
- Institute for Theoretical Physics II: Soft Matter, Heinrich-Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany.
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600MB, Eindhoven, The Netherlands.
| | - Andreas Kaiser
- Materials Science Division, Argonne National Laboratory, 9700 South Cass Av, Illinois, 60439, USA
| | - Hartmut Löwen
- Institute for Theoretical Physics II: Soft Matter, Heinrich-Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
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34
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Ehrig S, Ferracci J, Weinkamer R, Dunlop JWC. Curvature-controlled defect dynamics in active systems. Phys Rev E 2017; 95:062609. [PMID: 28709318 DOI: 10.1103/physreve.95.062609] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Indexed: 11/07/2022]
Abstract
We have studied the collective motion of polar active particles confined to ellipsoidal surfaces. The geometric constraints lead to the formation of vortices that encircle surface points of constant curvature (umbilics). We have found that collective motion patterns are particularly rich on ellipsoids with four umbilics where vortices tend to be located near pairs of umbilical points to minimize their interaction energy. Our results provide a perspective on the migration of living cells, which most likely use the information provided from the curved substrate geometry to guide their collective motion.
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Affiliation(s)
- Sebastian Ehrig
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14482 Potsdam, Germany
| | - Jonathan Ferracci
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14482 Potsdam, Germany
| | - Richard Weinkamer
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14482 Potsdam, Germany
| | - John W C Dunlop
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14482 Potsdam, Germany
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35
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Vortex Pattern of Corneal Deposits in Granular Corneal Dystrophy Associated With the p.(Arg555Trp) Mutation in TGFBI. Cornea 2017; 36:210-216. [PMID: 28060069 DOI: 10.1097/ico.0000000000001045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To describe 2 unrelated families with multiple members demonstrating a less commonly recognized vortex pattern of corneal deposits confirmed to be granular corneal dystrophy type 1 (GCD1) after identification of the p.(Arg555Trp) mutation in the transforming growth factor β-induced gene (TGFBI). METHODS A slit-lamp examination was performed on individuals from 2 families, one of Mexican descent and a second of Italian descent. After DNA extraction from affected individuals and their unaffected relatives, TGFBI screening was performed. RESULTS Eight of 20 individuals in the Mexican family and 20 of 55 in the Italian family demonstrated corneal stromal opacities. Seven of the 8 affected individuals in the Mexican family and 4 of the 20 affected individuals in the Italian family demonstrated a phenotype characterized by a "sea fan" or vortex pattern of superficial stromal corneal deposits originating from the inferior aspect of the cornea. Screening of TGFBI in both families revealed a heterozygous missense mutation [p.(Arg555Trp)] in exon 12, confirming the diagnosis of GCD1. CONCLUSIONS Our findings demonstrate that GCD1 may present with a vortex pattern of anterior stromal deposits. Although this pattern of dystrophic deposits is not recognized by clinicians as a typical phenotype of GCD1, it is consistent with the production of the majority of the TGFBI protein by the corneal epithelium.
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36
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Comparison of two related lines of tauGFP transgenic mice designed for lineage tracing. BMC DEVELOPMENTAL BIOLOGY 2017; 17:8. [PMID: 28662681 PMCID: PMC5492368 DOI: 10.1186/s12861-017-0149-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/01/2017] [Indexed: 12/18/2022]
Abstract
Background The tauGFP reporter fusion protein is produced nearly ubiquitously by the TgTP6.3 transgene in TP6.3 mice and its localisation to microtubules offers some advantages over soluble GFP as a lineage marker. However, TgTP6.3Tg/Tg homozygotes are not viable and TgTP6.3Tg/− hemizygotes are smaller than wild-type. TP6.4 mice carry the TgTP6.4 transgene, which was produced with the same construct used to generate TgTP6.3, so we investigated whether TgTP6.4 had any advantages over TgTP6.3. Results Although TgTP6.4Tg/Tg homozygotes died before weaning, TgTP6.4Tg/− hemizygotes were viable and fertile and only males were significantly lighter than wild-type. The TgTP6.4 transgene produced the tauGFP fusion protein by the 2-cell stage and it was widely expressed in adults but tauGFP fluorescence was weak or absent in several tissues, including some neural tissues. The TgTP6.4 transgene expression pattern changed over several years of breeding and mosaic transgene expression became increasingly common in all expressing tissues. This mosaicism was used to visualise clonal lineages in the adrenal cortex of TgTP6.4Tg/− hemizygotes and these were qualitatively and quantitatively comparable to lineages reported previously for other mosaic transgenic mice, X-inactivation mosaics and chimaeras. Mosaicism occurred less frequently in TP6.3 than TP6.4 mice and was only observed in the corneal epithelium and adrenal cortex. Conclusions Mosaic expression makes the TgTP6.4 transgene unsuitable for use as a conventional cell lineage marker but such mosaicism provides a useful system for visualising clonal lineages that arise during development or maintenance of adult tissues. Differences in the occurrence of mosaicism between related transgenic lines, such as that described for lines TP6.3 and TP6.4, might provide a useful system for investigating the mechanism of transgene silencing. Electronic supplementary material The online version of this article (doi:10.1186/s12861-017-0149-x) contains supplementary material, which is available to authorized users.
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Sartaj R, Zhang C, Wan P, Pasha Z, Guaiquil V, Liu A, Liu J, Luo Y, Fuchs E, Rosenblatt MI. Characterization of slow cycling corneal limbal epithelial cells identifies putative stem cell markers. Sci Rep 2017. [PMID: 28630424 PMCID: PMC5476663 DOI: 10.1038/s41598-017-04006-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In order to identify reliable markers of corneal epithelial stem cells, we employed an inducible transgenic “pulse-chase” murine model (K5Tta × TRE-H2BGFP) to localize, purify, and characterize slow cycling cells in the cornea. The retention of GFP labeling in slowly dividing cells allowed for localization of these cells to the corneal limbus and their subsequent purification by FACS. Transcriptome analysis from slow cycling cells identified differentially expressed genes when comparing to GFP- faster-dividing cells. RNA-Seq data from corneal epithelium were compared to epidermal hair follicle stem cell RNA-Seq to identify genes representing common putative stem cell markers or determinants, which included Sox9, Fzd7, Actn1, Anxa3 and Krt17. Overlapping retention of GFP and immunohistochemical expression of Krt15, ΔNp63, Sox9, Actn1, Fzd7 and Krt17 were observed in our transgenic model. Our analysis presents an array of novel genes as putative corneal stem cell markers.
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Affiliation(s)
- R Sartaj
- University of Illinois, Chicago, USA
| | - C Zhang
- Weill Cornell Medical College, New York, USA
| | - P Wan
- Weill Cornell Medical College, New York, USA
| | - Z Pasha
- University of Illinois, Chicago, USA
| | | | - A Liu
- Weill Cornell Medical College, New York, USA
| | - J Liu
- Weill Cornell Medical College, New York, USA
| | - Y Luo
- University of Illinois, Chicago, USA
| | - E Fuchs
- The Rockefeller University, New York, USA
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Bassnett S, Šikić H. The lens growth process. Prog Retin Eye Res 2017; 60:181-200. [PMID: 28411123 DOI: 10.1016/j.preteyeres.2017.04.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 01/17/2023]
Abstract
The factors that regulate the size of organs to ensure that they fit within an organism are not well understood. A simple organ, the ocular lens serves as a useful model with which to tackle this problem. In many systems, considerable variance in the organ growth process is tolerable. This is almost certainly not the case in the lens, which in addition to fitting comfortably within the eyeball, must also be of the correct size and shape to focus light sharply onto the retina. Furthermore, the lens does not perform its optical function in isolation. Its growth, which continues throughout life, must therefore be coordinated with that of other tissues in the optical train. Here, we review the lens growth process in detail, from pioneering clinical investigations in the late nineteenth century to insights gleaned more recently in the course of cell and molecular studies. During embryonic development, the lens forms from an invagination of surface ectoderm. Consequently, the progenitor cell population is located at its surface and differentiated cells are confined to the interior. The interactions that regulate cell fate thus occur within the obligate ellipsoidal geometry of the lens. In this context, mathematical models are particularly appropriate tools with which to examine the growth process. In addition to identifying key growth determinants, such models constitute a framework for integrating cell biological and optical data, helping clarify the relationship between gene expression in the lens and image quality at the retinal plane.
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Affiliation(s)
- Steven Bassnett
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, USA.
| | - Hrvoje Šikić
- Department of Mathematics, Faculty of Science, University of Zagreb, Croatia
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Silverman E, Zhao J, Merriam JC, Nagasaki T. Intracellular Position of Centrioles and the Direction of Homeostatic Epithelial Cell Movements in the Mouse Cornea. J Histochem Cytochem 2017; 65:83-91. [PMID: 28117631 DOI: 10.1369/0022155416674718] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Corneal epithelial cells exhibit continuous centripetal movements at a rate of about 30 µm per day, but neither the driving force nor the mechanism that determines the direction of movements is known. To facilitate the investigation of homeostatic cell movement, we examined if the intracellular position of a centriole can be used as a directional marker of epithelial cell movements in the mouse cornea. A direction of cell movements was estimated in fixed specimens from a pattern of underlying subepithelial nerve fibers. Intracellular position of centrioles was determined by gamma-tubulin immunohistology and plotted in a narrow strip along the entire diameter of a cornea from limbus to limbus. When we determined the position of centrioles in the peripheral cornea where cell movements proceed generally along a radial path, about 55% of basal epithelial cells contained a centriole in the front half of a cell. However, in the central cornea where cells exhibit a spiral pattern of movements, centrioles were distributed randomly. These results suggest that centrioles tend to be positioned toward the direction of movement in corneal basal epithelial cells when they are moving centripetally at a steady rate.
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Affiliation(s)
- Erika Silverman
- Department of Ophthalmology, Columbia University, New York, New York (ES, JZ, JCM, TN)
| | - Jin Zhao
- Department of Ophthalmology, Columbia University, New York, New York (ES, JZ, JCM, TN)
| | - John C Merriam
- Department of Ophthalmology, Columbia University, New York, New York (ES, JZ, JCM, TN)
| | - Takayuki Nagasaki
- Department of Ophthalmology, Columbia University, New York, New York (ES, JZ, JCM, TN)
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Kasetti RB, Gaddipati S, Tian S, Xue L, Kao WWY, Lu Q, Li Q. Study of corneal epithelial progenitor origin and the Yap1 requirement using keratin 12 lineage tracing transgenic mice. Sci Rep 2016; 6:35202. [PMID: 27734924 PMCID: PMC5062132 DOI: 10.1038/srep35202] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/27/2016] [Indexed: 12/14/2022] Open
Abstract
Key issues in corneal epithelium biology are the mechanism for corneal epithelium stem cells to maintain the corneal epithelial homeostasis and wound healing responses, and what are the regulatory molecular pathways involved. There are apparent discrepancies about the locations of the progenitor populations responsible for corneal epithelial self-renewal. We have developed a genetic mouse model to trace the corneal epithelial progenitor lineages during adult corneal epithelial homeostasis and wound healing response. Our data revealed that the early corneal epithelial progenitor cells expressing keratin-12 originated from limbus, and gave rise to the transit amplifying cells that migrated centripetally to differentiate into corneal epithelial cells. Our results support a model that both corneal epithelial homeostasis and wound healing are mainly maintained by the activated limbal stem cells originating form limbus, but not from the corneal basal epithelial layer. In the present study, we further demonstrated the nuclear expression of transcriptional coactivator YAP1 in the limbal and corneal basal epithelial cells and its essential role for maintaining the high proliferative potential of those corneal epithelial progenitor cells in vivo.
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Affiliation(s)
- Ramesh Babu Kasetti
- Departments of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Subhash Gaddipati
- Departments of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Shifu Tian
- Departments of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Lei Xue
- Department of Interventional Radiology, Shanghai 10th People’s Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Winston W.-Y. Kao
- Department of Ophthalmology, University of Cincinnati, OH 45267, USA
| | - Qingxian Lu
- Departments of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY 40202, USA
- James Graham Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Qiutang Li
- Departments of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, KY 40202, USA
- James Graham Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY 40202, USA
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Findlay AS, Panzica DA, Walczysko P, Holt AB, Henderson DJ, West JD, Rajnicek AM, Collinson JM. The core planar cell polarity gene, Vangl2, directs adult corneal epithelial cell alignment and migration. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160658. [PMID: 27853583 PMCID: PMC5099008 DOI: 10.1098/rsos.160658] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 09/15/2016] [Indexed: 05/13/2023]
Abstract
This study shows that the core planar cell polarity (PCP) genes direct the aligned cell migration in the adult corneal epithelium, a stratified squamous epithelium on the outer surface of the vertebrate eye. Expression of multiple core PCP genes was demonstrated in the adult corneal epithelium. PCP components were manipulated genetically and pharmacologically in human and mouse corneal epithelial cells in vivo and in vitro. Knockdown of VANGL2 reduced the directional component of migration of human corneal epithelial (HCE) cells without affecting speed. It was shown that signalling through PCP mediators, dishevelled, dishevelled-associated activator of morphogenesis and Rho-associated protein kinase directs the alignment of HCE cells by affecting cytoskeletal reorganization. Cells in which VANGL2 was disrupted tended to misalign on grooved surfaces and migrate across, rather than parallel to the grooves. Adult corneal epithelial cells in which Vangl2 had been conditionally deleted showed a reduced rate of wound-healing migration. Conditional deletion of Vangl2 in the mouse corneal epithelium ablated the normal highly stereotyped patterns of centripetal cell migration in vivo from the periphery (limbus) to the centre of the cornea. Corneal opacity owing to chronic wounding is a major cause of degenerative blindness across the world, and this study shows that Vangl2 activity is required for directional corneal epithelial migration.
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Affiliation(s)
- Amy S. Findlay
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, UK
| | - D. Alessio Panzica
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, UK
| | - Petr Walczysko
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, UK
| | - Amy B. Holt
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, UK
| | - Deborah J. Henderson
- Institute of Genetic Medicine, Newcastle University, Centre for Life, Newcastle upon Tyne NE1 3BZ, UK
| | - John D. West
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Ann M. Rajnicek
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, UK
| | - J. Martin Collinson
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Aberdeen AB25 2ZD, UK
- Author for correspondence: J. Martin Collinson e-mail:
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Renewal of the Holocrine Meibomian Glands by Label-Retaining, Unipotent Epithelial Progenitors. Stem Cell Reports 2016; 7:399-410. [PMID: 27523617 PMCID: PMC5031954 DOI: 10.1016/j.stemcr.2016.07.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 07/10/2016] [Accepted: 07/11/2016] [Indexed: 01/09/2023] Open
Abstract
The meibomian and sebaceous glands secrete lipids to prevent desiccation of the ocular surface and skin, respectively. Precisely how these holocrine tissues regenerate is not well understood. To address this, we characterized keratin 5(+) (K5) label-retaining cells (LRCs) and the lineage tracing of keratin 14 (K14) progenitors in mouse meibomian glands. Using the tet-off H2B-GFP/K5tTA mouse, H2B-GFP fluorescence dilutes 2-fold with every division in K5(+) cell nuclei after doxycycline administration. In 3D reconstructions generated over a >28-day doxycycline chase, we observed LRCs at the acinus entrance where K6(+) ductal epithelium terminates. For lineage tracing, K14CreER(T2)-Confetti mice were injected intraperitoneally with tamoxifen and euthanized at 23 and 59 weeks later. Meibomian gland acini in these mice were either monochromatic or dual-colored, whereas the duct exhibited multiple colors. In conclusion, LRCs are likely to direct meibomian gland turnover and may exist as two distinct unipotent progenitors that renew ductal and acinar tissue separately.
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43
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Lobo EP, Delic NC, Richardson A, Raviraj V, Halliday GM, Di Girolamo N, Myerscough MR, Lyons JG. Self-organized centripetal movement of corneal epithelium in the absence of external cues. Nat Commun 2016; 7:12388. [PMID: 27499113 PMCID: PMC4979063 DOI: 10.1038/ncomms12388] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 06/29/2016] [Indexed: 01/25/2023] Open
Abstract
Maintaining the structure of the cornea is essential for high-quality vision. In adult mammals, corneal epithelial cells emanate from stem cells in the limbus, driven by an unknown mechanism towards the centre of the cornea as cohesive clonal groups. Here we use complementary mathematical and biological models to show that corneal epithelial cells can self-organize into a cohesive, centripetal growth pattern in the absence of external physiological cues. Three conditions are required: a circumferential location of stem cells, a limited number of cell divisions and mobility in response to population pressure. We have used these complementary models to provide explanations for the increased rate of centripetal migration caused by wounding and the potential for stem cell leakage to account for stable transplants derived from central corneal tissue, despite the predominantly limbal location of stem cells. The cornea is formed of cells that originate from the outer circle of stem cells and that move towards its centre. Here, the authors show that the movement pattern is self-organised, requiring no cues, and that stem cell leakage may account for the presence of stem cells at the centre of the cornea.
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Affiliation(s)
- Erwin P Lobo
- School of Mathematics and Statistics, Camperdown, New South Wales 2006, Australia
| | - Naomi C Delic
- Discipline of Dermatology, Bosch Institute, Charles Perkins Centre, University of Sydney, Camperdown, New South Wales 2006, Australia.,Immune Imaging Program, Centenary Institute for Cancer Medicine and Cell Biology, Camperdown, New South Wales 2042, Australia
| | - Alex Richardson
- Department of Pathology, School of Medical Sciences, University of New South Wales, Randwick, New South Wales 2052, Australia
| | - Vanisri Raviraj
- Discipline of Dermatology, Bosch Institute, Charles Perkins Centre, University of Sydney, Camperdown, New South Wales 2006, Australia.,Immune Imaging Program, Centenary Institute for Cancer Medicine and Cell Biology, Camperdown, New South Wales 2042, Australia
| | - Gary M Halliday
- Discipline of Dermatology, Bosch Institute, Charles Perkins Centre, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Nick Di Girolamo
- Department of Pathology, School of Medical Sciences, University of New South Wales, Randwick, New South Wales 2052, Australia
| | - Mary R Myerscough
- School of Mathematics and Statistics, Camperdown, New South Wales 2006, Australia
| | - J Guy Lyons
- Discipline of Dermatology, Bosch Institute, Charles Perkins Centre, University of Sydney, Camperdown, New South Wales 2006, Australia.,Immune Imaging Program, Centenary Institute for Cancer Medicine and Cell Biology, Camperdown, New South Wales 2042, Australia.,Sydney Head and Neck Cancer Institute, Cancer Services, Royal Prince Alfred Hospital, Camperdown, New South Wales 2050, Australia
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44
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Pajic B, Vastardis I, Rajkovic P, Pajic-Eggspuehler B, Aebersold DM, Cvejic Z. A mathematical approach to human pterygium shape. Clin Ophthalmol 2016; 10:1343-9. [PMID: 27555741 PMCID: PMC4969044 DOI: 10.2147/opth.s106611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Pterygium is a common lesion affecting the population in countries with high levels of ultraviolet exposure. The final shape of a pterygium is the result of a growth pattern, which remains poorly understood. This manuscript provides a mathematical analysis as a tool to determine the shape of human pterygia. MATERIALS AND METHODS Eighteen patients, all affected by nasal unilateral pterygia, were randomly selected from our patient database independently of sex, origin, or race. We included all primary or recurrent pterygia with signs of proliferation, dry eye, and induction of astigmatism. Pseudopterygia were excluded from this study. Pterygia were outlined and analyzed mathematically using a Cartesian coordinate system with two axes (X, Y) and five accurate landmarks of the pterygium. RESULTS In 13 patients (72%), the shape of the pterygia was hyperbolic and in five patients (28%), the shape was rather elliptical. CONCLUSION This analysis gives a highly accurate mathematical description of the shape of human pterygia. This might help to better assess the clinical results and outcome of the great variety of therapeutic approaches concerning these lesions.
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Affiliation(s)
- Bojan Pajic
- Eye Clinic ORASIS, Swiss Eye Research Foundation, Reinach AG, Switzerland
- Department of Physics, Faculty of Sciences, University of Novi Sad, Novi Sad
- Faculty of Medicine of the Military Medical Academy, University of Defence, Belgrade, Serbia
- Division of Ophthalmology, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Iraklis Vastardis
- Eye Clinic ORASIS, Swiss Eye Research Foundation, Reinach AG, Switzerland
| | - Predrag Rajkovic
- Department of Mathematics, Faculty of Mechanical Engineering, University of Niš, Niš, Serbia
| | | | - Daniel M Aebersold
- Department of Radiation Oncology, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Zeljka Cvejic
- Department of Physics, Faculty of Sciences, University of Novi Sad, Novi Sad
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45
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Douvaras P, Dorà NJ, Mort RL, Lodge EJ, Hill RE, West JD. Abnormal corneal epithelial maintenance in mice heterozygous for the micropinna microphthalmia mutation Mp. Exp Eye Res 2016; 149:26-39. [PMID: 27235794 PMCID: PMC4974241 DOI: 10.1016/j.exer.2016.05.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/26/2016] [Accepted: 05/23/2016] [Indexed: 01/06/2023]
Abstract
We investigated the corneal morphology of adult Mp/+ mice, which are heterozygous for the micropinna microphthalmia mutation, and identified several abnormalities, which implied that corneal epithelial maintenance was abnormal. The Mp/+ corneal epithelium was thin, loosely packed and contained goblet cells in older mice. Evidence also suggested that the barrier function was compromised. However, there was no major effect on corneal epithelial cell turnover and mosaic patterns of radial stripes indicated that radial cell movement was normal. Limbal blood vessels formed an abnormally wide limbal vasculature ring, K19-positive cells were distributed more widely than normal and K12 was weakly expressed in the peripheral cornea. This raises the possibilities that the limbal-corneal boundary was poorly defined or the limbus was wider than normal. BrdU label-retaining cell numbers and quantitative clonal analysis suggested that limbal epithelial stem cell numbers were not depleted and might be higher than normal. However, as corneal epithelial homeostasis was abnormal, it is possible that Mp/+ stem cell function was impaired. It has been shown recently that the Mp mutation involves a chromosome 18 inversion that disrupts the Fbn2 and Isoc1 genes and produces an abnormal, truncated fibrillin-2MP protein. This abnormal protein accumulates in the endoplasmic reticulum (ER) of cells that normally express Fbn2 and causes ER stress. It was also shown that Fbn2 is expressed in the corneal stroma but not the corneal epithelium, suggesting that the presence of truncated fibrillin-2MP protein in the corneal stroma disrupts corneal epithelial homeostasis in Mp/+ mice. Heterozygous mutant Mp/+ mice have small, abnormal eyes. The corneal epithelium is thin, loosely packed and has goblet cells. Corneal epithelial cell turnover and radial cell movement appear normal. The cornea-limbal border is poorly defined and the limbus appears wider than normal. Indirect tests suggest stem cells are not depleted and numbers might be increased.
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Affiliation(s)
- Panagiotis Douvaras
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Natalie J Dorà
- Genes and Development Group, Centre for Integrative Physiology, Biomedical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Richard L Mort
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Emily J Lodge
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Robert E Hill
- Medical and Developmental Genetics Section, MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
| | - John D West
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
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Eghtedari Y, Richardson A, Mai K, Heng B, Guillemin GJ, Wakefield D, Di Girolamo N. Keratin 14 Expression in Epithelial Progenitor Cells of the Developing Human Cornea. Stem Cells Dev 2016; 25:699-711. [DOI: 10.1089/scd.2016.0039] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Yas Eghtedari
- Ocular Diseases Research Group, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Alexander Richardson
- Ocular Diseases Research Group, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Kelly Mai
- Ocular Diseases Research Group, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Benjamin Heng
- Neuroinflammation Group, Faculty of Medicine & Health Sciences, Macquarie University, Sydney, Australia
| | - Gilles J. Guillemin
- Neuroinflammation Group, Faculty of Medicine & Health Sciences, Macquarie University, Sydney, Australia
| | - Denis Wakefield
- Ocular Diseases Research Group, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Nick Di Girolamo
- Ocular Diseases Research Group, School of Medical Sciences, University of New South Wales, Sydney, Australia
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47
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Fate Mapping Mammalian Corneal Epithelia. Ocul Surf 2016; 14:82-99. [PMID: 26774909 DOI: 10.1016/j.jtos.2015.11.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/16/2015] [Accepted: 11/18/2015] [Indexed: 02/07/2023]
Abstract
The anterior aspect of the cornea consists of a stratified squamous epithelium, thought to be maintained by a rare population of stem cells (SCs) that reside in the limbal transition zone. Although migration of cells that replenish the corneal epithelium has been studied for over a century, the process is still poorly understood and not well characterized. Numerous techniques have been employed to examine corneal epithelial dynamics, including visualization by light microscopy, the incorporation of vital dyes and DNA labels, and transplantation of genetically marked cells that have acted as cell and lineage beacons. Modern-day lineage tracing utilizes molecular methods to determine the fate of a specific cell and its progeny over time. Classically employed in developmental biology, lineage tracing has been used more recently to track the progeny of adult SCs in a number of organs to pin-point their location and understand their movement and influence on tissue regeneration. This review highlights key discoveries that have led researchers to develop cutting-edge genetic tools to effectively and more accurately monitor turnover and displacement of cells within the mammalian corneal epithelium. Collating information on the basic biology of SCs will have clinical ramifications in furthering our knowledge of the processes that govern their role in homeostasis, wound-healing, transplantation, and how we can improve current unsatisfactory SC-based therapies for patients suffering blinding corneal disease.
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48
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Amitai-Lange A, Berkowitz E, Altshuler A, Dbayat N, Nasser W, Suss-Toby E, Tiosano B, Shalom-Feuerstein R. A Method for Lineage Tracing of Corneal Cells Using Multi-color Fluorescent Reporter Mice. J Vis Exp 2015:e53370. [PMID: 26709460 PMCID: PMC4694035 DOI: 10.3791/53370] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Lineage tracing experiments define the origin, fate and behavior of cells in a specific tissue or organism. This technique has been successfully applied for many decades, revealing seminal findings in developmental biology. More recently, it was adopted by stem cell biologists to identify and track different stem cell populations with minimal experimental intervention. The recent developments in mouse genetics, the availability of a large number of mouse strains, and the advancements in fluorescent microscopy allow the straightforward design of powerful lineage tracing systems for various tissues with basic expertise, using commercially available tools. We have recently taken advantage of this powerful methodology to explore the origin and fate of stem cells at the ocular surface using R26R-Confetti mouse. This model offers a multi-color genetic system, for the expression of 4 fluorescent genes in a random manner. Here we describe the principles of this methodology and provide an adaptable protocol for designing lineage tracing experiments; specifically for the corneal epithelium as well as for other tissues.
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Affiliation(s)
- Aya Amitai-Lange
- Department of Genetics and Developmental Biology, The Ruth and Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology
| | - Eran Berkowitz
- Department of Ophthalmology, Hillel Yaffe Medical Center
| | - Anna Altshuler
- Department of Genetics and Developmental Biology, The Ruth and Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology
| | - Noora Dbayat
- Department of Ophthalmology, Hillel Yaffe Medical Center
| | - Waseem Nasser
- Department of Genetics and Developmental Biology, The Ruth and Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology
| | - Edith Suss-Toby
- Bioimging Center, Biomedical Core Facility, The Ruth and Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology
| | | | - Ruby Shalom-Feuerstein
- Department of Genetics and Developmental Biology, The Ruth and Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology;
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Dorà NJ, Hill RE, Collinson JM, West JD. Lineage tracing in the adult mouse corneal epithelium supports the limbal epithelial stem cell hypothesis with intermittent periods of stem cell quiescence. Stem Cell Res 2015; 15:665-677. [PMID: 26554513 PMCID: PMC4686565 DOI: 10.1016/j.scr.2015.10.016] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/26/2015] [Accepted: 10/26/2015] [Indexed: 12/24/2022] Open
Abstract
The limbal epithelial stem cell (LESC) hypothesis proposes that LESCs in the corneal limbus maintain the corneal epithelium both during normal homeostasis and wound repair. The alternative corneal epithelial stem cell (CESC) hypothesis proposes that LESCs are only involved in wound repair and CESCs in the corneal epithelium itself maintain the corneal epithelium during normal homeostasis. We used tamoxifen-inducible, CreER-loxP lineage tracing to distinguish between these hypotheses. Clones of labelled cells were induced in adult CAGG-CreER;R26R-LacZ reporter mice and their distributions analysed after different chase periods. Short-lived clones, derived from labelled transient amplifying cells, were shed during the chase period and long-lived clones, derived from stem cells, expanded. At 6 weeks, labelled clones appeared at the periphery, extended centripetally as radial stripes and a few reached the centre by 14 weeks. Stripe numbers depended on the age of tamoxifen treatment. Stripes varied in length, some were discontinuous, few reached the centre and almost half had one end at the limbus. Similar stripes extended across the cornea in CAGG-CreER;R26R-mT/mG reporter mice. The distributions of labelled clones are inconsistent with the CESC hypothesis and support the LESC hypothesis if LESCs cycle between phases of activity and quiescence, each lasting several weeks.
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Affiliation(s)
- Natalie J Dorà
- Centre for Integrative Physiology, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Robert E Hill
- Medical and Developmental Genetics Section, MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
| | - J Martin Collinson
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - John D West
- Centre for Integrative Physiology, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK.
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Di Girolamo N, Bobba S, Raviraj V, Delic NC, Slapetova I, Nicovich PR, Halliday GM, Wakefield D, Whan R, Lyons JG. Tracing the fate of limbal epithelial progenitor cells in the murine cornea. Stem Cells 2015; 33:157-69. [PMID: 24966117 DOI: 10.1002/stem.1769] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 05/24/2014] [Indexed: 12/15/2022]
Abstract
Stem cell (SC) division, deployment, and differentiation are processes that contribute to corneal epithelial renewal. Until now studying the destiny of these cells in a living mammal has not been possible. However, the advent of inducible multicolor genetic tagging and powerful imaging technologies has rendered this achievable in the translucent and readily accessible murine cornea. K14CreER(T2)-Confetti mice that harbor two copies of the Brainbow 2.1 cassette, yielding up to 10 colors from the stochastic recombination of fluorescent proteins, were used to monitor K-14(+) progenitor cell dynamics within the corneal epithelium in live animals. Multicolored columns of cells emerged from the basal limbal epithelium as they expanded and migrated linearly at a rate of 10.8 µm/day toward the central cornea. Moreover, the permanent expression of fluorophores, passed on from progenitor to progeny, assisted in discriminating individual clones as spectrally distinct streaks containing more than 1,000 cells within the illuminated area. The centripetal clonal expansion is suggestive that a single progenitor cell is responsible for maintaining a narrow corridor of corneal epithelial cells. Our data are in agreement with the limbus as the repository for SC as opposed to SC being distributed throughout the central cornea. This is the first report describing stem/progenitor cell fate determination in the murine cornea using multicolor genetic tracing. This model represents a powerful new resource to monitor SC kinetics and fate choice under homeostatic conditions, and may assist in assessing clonal evolution during corneal development, aging, wound-healing, disease, and following transplantation.
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Affiliation(s)
- N Di Girolamo
- School of Medical Sciences, University of New South Wales, Sydney, Australia
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