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Ortiz-Melo MT, Garcia-Murillo MJ, Salazar-Rojas VM, Campos JE, Castro-Muñozledo F. Transcriptional profiles along cell programming into corneal epithelial differentiation. Exp Eye Res 2020; 202:108302. [PMID: 33098888 DOI: 10.1016/j.exer.2020.108302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/23/2020] [Accepted: 10/12/2020] [Indexed: 12/15/2022]
Abstract
Using the rabbit corneal epithelial cell line RCE1(5T5) as a model, we analyzed three differentiation stages, distinguished on basis to the growth state of cultured cells and after studying the expression of transcription factors such as Oct4, Pax6 and ΔNp63α, selected differentiation markers, and signaling or epigenetic markers such as Notch receptors and Prdm3. Namely, proliferative non-differentiated cells, committed cells, and cells that constitute a stratified epithelium with a limbal epithelial-like structure. RNAseq based transcriptome analysis showed that 4891 genes were differentially expressed among these stages displaying distinctive gene signatures: proliferative cells had 1278 genes as gene signature, and seem to be early epithelial progenitors with an Oct4+, KLF4+, Myc+, ΔNp63α+, ABCG2+, Vimentin+, Zeb1+, VANGL1+, Krt3-, Krt12- phenotype. Committed cells had a gene signature with 417 genes and displayed markers indicative of the beginning of corneal differentiation, and genes characteristic of proliferative cells; we found the possible participation of Six3 and Six4 transcription factors along this stage. The third stage matches with a stratified corneal epithelium (gene signature comprising 979 genes) and is typified by an increase in the expression of WNT10A and NOTCH 2 and 3 signaling and Cux1 transcription factor, besides Pax6, KLF4 or Sox9. The differentiated cells express about 50% of the genes that belong to the Epidermal Differentiation Complex (EDC). Analysis of the differences between corneal epithelium and epidermis could be crucial to understand the regulatory mechanisms that lead to the expression of the differentiated phenotype.
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Affiliation(s)
- María Teresa Ortiz-Melo
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740. México City, 07000, Mexico; Unidad de Biotecnología y Prototipos, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Ap. Postal 314, 54000, Tlalnepantla, Edo. de México, Mexico; Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México. Unidad de Posgrado, Edificio A, 1° Piso, Circuito de Posgrados, Ciudad Universitaria, Coyoacán, C.P. 04510, Ciudad de México, Mexico
| | - Maria Jimena Garcia-Murillo
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740. México City, 07000, Mexico
| | - Víctor Manuel Salazar-Rojas
- Unidad de Biotecnología y Prototipos, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Ap. Postal 314, 54000, Tlalnepantla, Edo. de México, Mexico
| | - Jorge E Campos
- Unidad de Biotecnología y Prototipos, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Ap. Postal 314, 54000, Tlalnepantla, Edo. de México, Mexico
| | - Federico Castro-Muñozledo
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del IPN, Apdo. Postal 14-740. México City, 07000, Mexico.
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Gao Y, Li H, Han Q, Li Y, Wang T, Huang C, Mao Y, Wang X, Zhang Q, Tian J, Irwin DM, Tan H, Guo H. Overexpression of DUSP6 enhances chemotherapy-resistance of ovarian epithelial cancer by regulating the ERK signaling pathway. J Cancer 2020; 11:3151-3164. [PMID: 32231719 PMCID: PMC7097933 DOI: 10.7150/jca.37267] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 01/19/2020] [Indexed: 12/11/2022] Open
Abstract
Objective: DUSP6 is a negative regulator of the ERK signaling pathway and plays an important role in chemotherapy-resistance. Previously we showed that DUSP6 is overexpressed in ovarian cancer side population (SP) cells that possess cancer stem cell-like properties and are quiescent and chemotherapy-resistant. Here, we explore the effects of DUSP6 on chemotherapy-resistance by examining its regulation of the ERK signaling pathway and G0/G1 cell cycle arrest. Methods: mRNA and protein expression of DUSP6 and G0/G1 cell cycle checkpoint regulating proteins (CyclinD1, CyclinD3 and CyclinE2) was evaluated among ovarian cancer cell lines and tissue samples. Ovarian cancer cells were transiently transfected to overexpress DUSP6. After treatment with cisplatin, cell viability was measured by the MTS assay at 48 hours and the half maximal inhibitory concentration (IC50) for each cell line was calculated. Subcellular localization and cell cycle analysis were determined by using immunofluorescence and FACS, respectively. Results: SKOV3 and OVCAR8 SP cells were shown to express higher levels of DUSP6 and lower levels of CyclinD3 compared with non-SP (NSP) cells (P<0.001). Among 39 ovarian cancer tissue samples, expression of DUSP6 in the chemotherapy-resistant group (12 samples) was higher than in the chemotherapy-sensitive group (27 samples) (P<0.05). While a lower level of expression of CyclinD3 was seen in the chemotherapy-resistant group, it was not statistically different from the chemotherapy-sensitive group. HO8910 cells where shown to have higher IC50 to cisplatin than SKOV3 or OVCAR8 cells, and this correlated with higher levels of DUSP6 expression. Overexpression of DUSP6 in SKOV3 cells led to an increase in cisplatin IC50 values (P<0.05), and also markedly reduced the expression levels of phospho-ERK1/2 and CyclinD3 and to the predominance of cells in the G0/G1 phase. Conclusion: Our findings reveal an enhancement of chemotherapy-resistance and a predominance of cells in G1 cell cycle arrest in DUSP6-overexpressing ovarian cancer cells. This suggests that overexpression of DUSP6 promotes chemotherapy-resistance through the negative regulation of the ERK signaling pathway, increasing the G0/G1 phase ratio among ovarian cancer cells, and leading to cellular quiescence.
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Affiliation(s)
- Yan Gao
- Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing
| | - Hui Li
- Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing
| | - Qing Han
- Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing
| | - Yuan Li
- Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing
| | - Tongxia Wang
- Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing
| | - Cuiyu Huang
- Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing
| | - Yiqing Mao
- Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing
| | - Xi Wang
- Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing
| | - Qun Zhang
- Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing
| | - Junrui Tian
- Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing
| | - David M Irwin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Huanran Tan
- Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing
| | - Hongyan Guo
- Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing
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Abstract
BACKGROUND Reconstruction of the conjunctiva is an essential part of ocular surface reconstruction. Clinically applied and experimentally tested tissue- and stem-cell-based approaches are presented and evaluated. MATERIALS AND METHODS Current literature and our own results will be presented. RESULTS Autologous conjunctiva, mucous membrane of the mouth or nose, and amniotic membrane are routinely used for conjunctival reconstruction. Limitations are limited availability, involvement in autoimmune diseases, donor heterogeneity, and degradation in an inflamed environment. Experimentally tested matrices as tissues made from extracellular matrix proteins, synthetic polymers, temperature-sensitive culture dishes, and decellularized conjunctiva have been tested in vitro and partly in vivo. To replace conjunctival cells, cells of conjunctiva and mucous membrane of mouth and nose have been evaluated and show progenitor cell properties as well as secretory capacity (goblet cell differentiation). CONCLUSIONS Although different matrices are available for conjunctival reconstruction there is-due to specific limitations of existing tissues-a need for the development of new therapies for conjunctival replacement. Matrices produced in the laboratory have already been partly investigated in vivo and may thus be clinically applicable in the near future. Adult mucous membrane cells show many properties of conjunctival epithelium after expansion in vitro and thus are a promising cell source for conjunctival tissue engineering. Other stem cells sources require further evaluation.
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Wolosin JM, Zamudio A, Wang Z. Application of JC1 for non-toxic isolation of cells with MDR transporter activity by flow cytometry. PLoS One 2017; 12:e0174905. [PMID: 28380010 PMCID: PMC5381900 DOI: 10.1371/journal.pone.0174905] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 03/17/2017] [Indexed: 12/31/2022] Open
Abstract
The DNA intercalating dye Hoechst 33342 or its close analog DCV are actively removed from cells by the multidrug resistance transporter ABCG2, a protein overexpressed in metastatic cells and somatic stem cells. In bivariate blue-red flow cytometry fluorescent plots active Hoechst or DCV efflux combined with a concentration dependent bathochromic shifts of these nuclear dyes leads to the segregation of the transporter-rich cells into a distinct cell cohort tilted towards the shorter wavelength axis of the plot, the cohort is generically known as the side population (SP). This feature has facilitated the surface marker-independent isolation of live stem cells. A drawback, though, is the known toxicity of Hoechst dyes. In this study we show that JC1, a bathochromic mitochondrial membrane potential-sensitive dye applied at proper concentration, can yield flow cytometry fluorescent emission bivariate plots containing a low JC1 accumulation (JC1low) cohort. Using a combination of multiple cell lines, ABC-transporter inhibitors and viral vector-driven insertion of the ABCG2 gene or ABCG2 and ABCB1 shRNAs we demonstrate that JC1low can be generated by either of the two aforementioned multidrug resistance transporters. Complete wash out of mitochondrial bound JC1 required more than 24 h. In spite of this tight binding, the dye did not affect either the mitochondrial membrane potentials or the proliferation rate. In contrast, contemporaneous with its nuclear accumulation, Hoechst 33342 or DVC, caused changes in the fluorescent emission of mitochondrial membrane potential sensitive dyes resembling the effects caused by the mitochondrial uncoupler FCCP. In a number of cell lines exposure to Hoechst resulted in marked slow-down of proliferation and abolition of ABCG2 transport activity during the subsequent 2 days but in K562 cells the exposure induced cell extended death. Overall, its lack of toxicity vis. a vis. the toxicity and genotoxicity of the DNA intercalating dyes makes JC1 an ideal tool for isolating live cells expressing high multidrug resistance transport activity.
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Affiliation(s)
- J. Mario Wolosin
- Department of Ophthalmology, the Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
- Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
- * E-mail:
| | - Aldo Zamudio
- Department of Ophthalmology, the Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Zheng Wang
- Department of Ophthalmology, the Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
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Bath C, Muttuvelu D, Emmersen J, Vorum H, Hjortdal J, Zachar V. Transcriptional dissection of human limbal niche compartments by massive parallel sequencing. PLoS One 2013; 8:e64244. [PMID: 23717577 PMCID: PMC3661480 DOI: 10.1371/journal.pone.0064244] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Accepted: 04/10/2013] [Indexed: 12/13/2022] Open
Abstract
Corneal epithelium is maintained throughout life by well-orchestrated proliferation of limbal epithelial stem cells (LESCs), followed by migration and maturation centripetally towards the ocular surface. Disturbance of LESCs can potentially lead to a blinding condition, which can be reversed by reconstitution of a functional LESC pool. The current clinical procedures are effective to some degree, however, deeper knowledge of the molecular interplay within the limbal niche is necessary to achieve a fully satisfactory patient outcome. The present study was thus undertaken to carry out a comprehensive transcriptome analysis of four distinct human limbal compartments, including basal limbal crypts (BLCs), superficial limbal crypts (SLCs), cornea, and the supporting stroma, with the aid of laser capture microdissection and deep RNA sequencing. The tissue harvest pipeline was rigorously optimized so that the exposure to cold ischemia would be less than five minutes. The global gene ontology analysis confirmed existence of primitive cells in BLCs, migratory and activated cells in SLCs, and differentiated cells in cornea. Interestingly, many significantly upregulated genes in SLCs mapped to processes involved in regulation of vasculature, such as sFLT1. In contrast, BLCs exhibited many genes mapping to neurogenic processes and processes related to cell development. The primitive nature of BLCs was, furthermore, confirmed by the KEGG pathway analysis, and some potential regulators of LESCs were revealed, such as Lrig1 and SOX9. The analysis also yielded comprehensive lists of uniquely expressed genes in both BLCs and cornea, which may be useful to identify possible biomarkers. In conclusion, the current investigation provides new insight into the relationship between distinct cell populations within the limbal niche, identifies candidates to be verified for novel biological functions, and yields a wealth of information for prospective data mining.
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Affiliation(s)
- Chris Bath
- Department of Ophthalmology, Aalborg University Hospital, Aalborg, Denmark
- Laboratory for Stem Cell Research, Aalborg University, Aalborg, Denmark
| | - Danson Muttuvelu
- Department of Ophthalmology, Aalborg University Hospital, Aalborg, Denmark
| | - Jeppe Emmersen
- Laboratory for Stem Cell Research, Aalborg University, Aalborg, Denmark
| | - Henrik Vorum
- Department of Ophthalmology, Aalborg University Hospital, Aalborg, Denmark
| | - Jesper Hjortdal
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | - Vladimir Zachar
- Laboratory for Stem Cell Research, Aalborg University, Aalborg, Denmark
- * E-mail:
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Ocular surface development and gene expression. J Ophthalmol 2013; 2013:103947. [PMID: 23533700 PMCID: PMC3595720 DOI: 10.1155/2013/103947] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 01/16/2013] [Indexed: 01/10/2023] Open
Abstract
The ocular surface-a continuous epithelial surface with regional specializations including the surface and glandular epithelia of the cornea, conjunctiva, and lacrimal and meibomian glands connected by the overlying tear film-plays a central role in vision. Molecular and cellular events involved in embryonic development, postnatal maturation, and maintenance of the ocular surface are precisely regulated at the level of gene expression by a well-coordinated network of transcription factors. A thorough appreciation of the biological characteristics of the ocular surface in terms of its gene expression profiles and their regulation provides us with a valuable insight into the pathophysiology of various blinding disorders that disrupt the normal development, maturation, and/or maintenance of the ocular surface. This paper summarizes the current status of our knowledge related to the ocular surface development and gene expression and the contribution of different transcription factors to this process.
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Yang Y, Yang H, Wang Z, Mergler S, Wolosin JM, Reinach PS. Functional TRPV1 expression in human corneal fibroblasts. Exp Eye Res 2013; 107:121-9. [PMID: 23232207 PMCID: PMC3556194 DOI: 10.1016/j.exer.2012.11.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 11/09/2012] [Accepted: 11/13/2012] [Indexed: 12/31/2022]
Abstract
Corneal wound healing in mice subsequent to an alkali burn results in dysregulated inflammation and opacification. Transient receptor potential vanilloid subtype 1 (TRPV1) channel activation in all tissue layers by endogenous ligands contributes to this sight compromising outcome since in TRPV1 knockout mice wound healing results instead in tissue transparency restoration. However, it is not known if primary human stromal fibroblasts exhibit such expression even though functional TRPV1 expression is evident in an immortalized human corneal epithelial cell line. In primary human corneal fibroblasts (HCF), TRPV1 gene expression and localization were identified based on the results of quantitative RT-PCR and immunocytochemistry, respectively. Western blot analysis identified a 100 kD protein corresponding to TRPV1 protein expression in a positive control. Single-cell fluorescence imaging detected in fura2-AM loaded cells Ca(2+) transients that rose 1.8-fold above the baseline induced by a selective TRPV1 agonist, capsaicin (CAP), which were blocked by a TRPV1 antagonist, capsazepine (CPZ) or exposure to a Ca(2+) free medium. The whole-cell mode of the planar patch-clamp technique identified TRPV1-induced currents that rose 1.76-fold between -60 and +130 mV. CAP-induced time dependent changes in the phosphorylation status of mitogen activated protein kinase (MAPK) signaling mediators that led to a 2.5-fold increase in IL-6 release after 24 h. This rise did not occur either in TRPV1 siRNA gene silenced cells or during exposure to SB203580 (10 μM), a selective p38 MAPK inhibitor. Taken together, identification of functional TRPV1 expression in HCF suggests that in vivo its activation by injury contributes to corneal opacification and inflammation during wound healing. These undesirable effects may result in part from increases in IL-6 expression mediated by p-p38 MAPK signaling.
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Affiliation(s)
- Yuanquan Yang
- Department of Biological Sciences, State University of New York, State College of Optometry,, New York, NY 10036
| | - Hua Yang
- Department of Biological Sciences, State University of New York, State College of Optometry,, New York, NY 10036
| | - Zheng Wang
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY 10029
| | - Stefan Mergler
- Department of Ophthalmology, Charité, University Berlin, Campus Virchow-Clinic, Berlin, Germany
| | - J. Mario Wolosin
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY 10029
| | - Peter S. Reinach
- Department of Biological Sciences, State University of New York, State College of Optometry,, New York, NY 10036
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Abstract
The cornea is the transparent front part of the eye and comprises three distinct cell layers. One of these cell layers is a self-renewing epithelium long believed to harbor a resident stem cell population. The location and characteristics of corneal epithelial stem cells have now been confirmed by several research groups, and these cells are currently applied therapeutically. The corneal stroma and endothelium are largely quiescent after infancy, and until recently they were not considered to undergo self-renewal or to maintain stem cells. This view was overturned during the last two decades. At present, cell populations with characteristics of adult stem cells are routinely isolated and characterized from the limbal stroma and the corneal -endothelium. This chapter describes methods for isolation and culture of limbal stromal cells and corneal endothelial cells.
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Affiliation(s)
- Naresh Polisetti
- Department of Ophthalmology, University of Erlangen-Nürnberg, Erlangen, Germany
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Nieto-Miguel T, Calonge M, de la Mata A, López-Paniagua M, Galindo S, de la Paz MF, Corrales RM. A comparison of stem cell-related gene expression in the progenitor-rich limbal epithelium and the differentiating central corneal epithelium. Mol Vis 2011; 17:2102-17. [PMID: 21850186 PMCID: PMC3156782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 07/28/2011] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Corneal epithelium is maintained by a population of stem cells (SCs) that have not been identified by specific molecular markers. The objective of this study was to find new putative markers for these SCs and to identify associated molecular pathways. METHODS Real time PCR (rt-PCR) was performed in 24 human limbal and central corneal epithelial samples to evaluate the gene expression profile of known corneal epithelial SC-associated markers. A pool of those samples was further analyzed by a rt-PCR array (RT²-PCR-A) for 84 genes related to the identification, growth, maintenance, and differentiation of SCs. RESULTS Cells from the corneal epithelium SC niche showed significant expression of ATP-binding cassette sub-family G member 2 (ABCG2) and cytokeratin (KRT)15, KRT14, and KRT5 genes. RT²-PCR-A results indicated an increased or decreased expression in 21 and 24 genes, respectively, in cells from the corneal SC niche compared to cells from the central corneal epithelium. Functional analysis by proprietary software found 4 different associated pathways and a novel network with the highest upregulated genes in the corneal SC niche. This led to the identification of specific molecules, chemokine (C-X-C motif) ligand 12 (CXCL12), islet-1 transcription factor LIM/homeodomain (ISL1), collagen-type II alpha 1 (COL2A), neural cell adhesion molecule 1 (NCAM1), aggrecan (ACAN), forkhead box A2 (FOXA2), Gap junction protein beta 1/connexin 32 (GJB1/Cnx32), and Msh homeobox 1 (MSX1), that could be used to recognize putative corneal epithelial SCs grown in culture and intended for transplantation. Other molecules, NCAM1 and GJB1/Cnx32, potentially could be used to positively purify them, and Par-6 partitioning defective 6 homolog alpha (PARD6A) to negatively purify them. CONCLUSIONS Knowledge of these gene and molecular pathways has provided a better understanding of the signaling molecular pathways associated with progenitor-rich limbal epithelium. This knowledge potentially could give support to the design and development of innovative therapies with the potential to reverse corneal blindness arising from ocular surface failure.
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Affiliation(s)
- Teresa Nieto-Miguel
- Institute for Applied Ophthalmobiology (IOBA), University of Valladolid, Valladolid, Spain,Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Valladolid, Spain
| | - Margarita Calonge
- Institute for Applied Ophthalmobiology (IOBA), University of Valladolid, Valladolid, Spain,Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Valladolid, Spain
| | - Ana de la Mata
- Institute for Applied Ophthalmobiology (IOBA), University of Valladolid, Valladolid, Spain,Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Valladolid, Spain
| | - Marina López-Paniagua
- Institute for Applied Ophthalmobiology (IOBA), University of Valladolid, Valladolid, Spain,Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Valladolid, Spain
| | - Sara Galindo
- Institute for Applied Ophthalmobiology (IOBA), University of Valladolid, Valladolid, Spain,Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Valladolid, Spain
| | | | - Rosa M. Corrales
- Institute for Applied Ophthalmobiology (IOBA), University of Valladolid, Valladolid, Spain,Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Valladolid, Spain
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Selver OB, Barash A, Ahmed M, Wolosin JM. ABCG2-dependent dye exclusion activity and clonal potential in epithelial cells continuously growing for 1 month from limbal explants. Invest Ophthalmol Vis Sci 2011; 52:4330-7. [PMID: 21421882 DOI: 10.1167/iovs.10-5897] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
PURPOSE To determine changes in ABCG2-transport-dependent dye exclusion in outgrowths from limbal explants. METHODS Human or rabbit limbal strips were deposited onto inserts. Over a month, the segments were twice transferred to new inserts. Fresh tissue (FT) cells, obtained by sequential dispase-trypsin digestion and the cells growing from the explant cultures, were characterized for ABCG2-dependent efflux by flow cytometry using a newly identified substratum, JC1. Rabbit cells were sorted into JC1-excluding (JC1(low)) and main (JC1(main)) cohorts and seeded with feeder 3T3 cells to determine colony formation efficiency (CFE). RESULTS The JC1(low) cells were all Hoechst 33342-excluding cells and vice versa, establishing the physical equivalence between JC1(low) and the side population (SP). JC1(low) cell content was reduced by three ABCG2-specific inhibitors: FTC, Ko143, and glafenine. JC1(low) percentiles for the fresh human and rabbit cells were 1.4% and 4.1% and CFEs for rabbit JC1(low) and JC1(main) were 1.2% and 5.3%. In contrast, the respective JC1(low) percentiles in the first and second outgrowths were 19.5% and 27.4% and 25.8% and 32.5%, and the rabbit JC1(low) and JC1(main) CFEs were 12.3% and 0.9%. Thus, although in FT the contribution of the JC1(low) cohort to the CFE is minimal, in the explant culture the phenotype incorporates >80% of the CFE. CONCLUSIONS ABCG2-dependent dye exclusion undergoes a large expansion in explant culture and becomes associated with a high CFE. The transport increase is more pronounced at late outgrowth times, suggesting permanence of stem cells within the explant.
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11
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Wang Z, Reinach PS, Zhang F, Vellonen KS, Urtti A, Turner H, Wolosin JM. DUSP5 and DUSP6 modulate corneal epithelial cell proliferation. Mol Vis 2010; 16:1696-704. [PMID: 20806045 PMCID: PMC2927432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Accepted: 08/18/2010] [Indexed: 10/25/2022] Open
Abstract
PURPOSE Dual specificity phosphatases (DUSPs) modulate the duration and magnitude of phospho-activation of Erk1/2, p38 and JNK1/2, the terminal kinases (TKs) of the mitogen activated protein kinase (MAPK) cascades. Three DUSPs, DUSP1, DUSP5, and DUSP6, are overexpressed in ocular surface side population stem cells (SPSCs). Our objective was to identify the impact of these enzymes on TK phosphorylation and proliferation of corneal epithelial cells. METHODS SV40 immortalized (sv) and expanded fresh human corneal epithelial cells (efHCECs) were transduced with lentivectors to elicit expression of shRNAmir against DUSP1, DUSP5, and JNK1 to thereby create the DUSP1i, DUSP5i and JNKi cell sublines, or overexpress DUSP6 (henceforth DUSP6(+)), respectively. TK phosphorylation status and proliferation rates were determined by immunoblotting and (3)H thymidine uptake. RESULTS In both ef and svHCECs, EGF supplementation after a 24 h serum starvation caused a rapid 5-15 min spike in the phosphorylation of all three TK types. This was followed by gradual decreases to low phosphorylation levels within one h. These declines coincided with dramatic increases in DUSP1 and DUSP5 protein expression. In DUSP1i, the DUSP1 increase was abolished. All 3 TKs maintained high phosphorylation levels for at least 90 min and proliferation rates were unchanged from non-transduced cells. In DUSP5i, the DUSP5 protein increase was prevented, the post peak phosphorylation decrease occurred only on Erk1/2 and the proliferation rate increased by 50%-60%. In JNK1i, JNK1 was essentially knocked out and proliferation rates were also markedly elevated. At steady-state, DUSP1i maintained high levels of pJNK1/2 expression. In DUSP6(+) Erk1/2 phosphorylation was prevented and proliferation rates decreased to less than 50%. CONCLUSIONS DUSP5 and DUSP6 selectively control ERK pathway activity and proliferation. The lack of an effect of DUSP1 knockdown on proliferation can be attributed to its pan-MAPK effect. The expected augmented proliferative response due to enhanced and prolonged phosphorylation of Erk1/2 following DUSP1 knockdown does not occur because a pJNK1/2 antiproliferative effect is simultaneously unleashed.
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Affiliation(s)
- Zheng Wang
- Department of Biological Sciences, SUNY State College of Optometry, New York, NY
| | - Peter S. Reinach
- Department of Biological Sciences, SUNY State College of Optometry, New York, NY
| | - Fan Zhang
- Department of Biological Sciences, SUNY State College of Optometry, New York, NY
| | | | - Arto Urtti
- Centre for Drug Research, University of Helsinki, Helsinki, Finland
| | - Helen Turner
- Department of Ophthalmology and the Black Family Stem cell Institute, Mount Sinai School of Medicine, New York, NY
| | - J. Mario Wolosin
- Department of Ophthalmology and the Black Family Stem cell Institute, Mount Sinai School of Medicine, New York, NY
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12
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Akinci MAM, Turner H, Taveras M, Wolosin JM. Differential gene expression in the pig limbal side population: implications for stem cell cycling, replication, and survival. Invest Ophthalmol Vis Sci 2009; 50:5630-8. [PMID: 19608544 DOI: 10.1167/iovs.09-3791] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
PURPOSE To define the molecular signature of limbal SP cells and identify signaling pathways associated with the phenotype of these putative stem cells. METHODS Primary cultures of pig limbal epithelial cells stained with Hoechst 33342 were sorted by flow cytometry into SP and non-SP cells, and purified RNA was processed for microarray analysis with an oligonucleotide spotted array. Expressed transcripts for which SP and non-SP expressions differed by more that 1.5-fold in each paired set and by twofold overall were considered to be differentially expressed. Differential expression was validated by quantitative PCR and immunostaining. Data-mining methods were used to identify cellular processes that are either salient or depressed in the SP cells. RESULTS The microarray identified approximately 9000 distinct, expressed, and identifiable genes. Of those, 382 and 296 were either over- or underexpressed in the SP cells, respectively. Overrepresentation analysis indicated that SP cells are in a low metabolic and biosynthetic state. In addition, a pattern of elevated MXD1, MAXI2, DUSP5, p27/KIP1, and p57/KIP2 and decreased Cyclin D and CDK genes can be expected to slow intrinsic and mitogen-induced G(1)-to-S cell cycle transition. SP cells were also rich in genes associated with stem cell phenotype and genes providing protection against oxidative and/or xenobiotic damage. CONCLUSIONS Microarray analysis of pig limbal SP cells yielded a molecular signature underscoring a phenotype characterized by slow cycling and low metabolic activity. The results provide valuable insights for the preservation and/or replication of epithelial stem cells.
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Affiliation(s)
- M A Murat Akinci
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, New York 10029, USA
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