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Saranya P, Shekhar M, Haripriya A, Muthukkaruppan V, Gowri Priya C. Towards the Identification and Characterization of Putative Adult Human Lens Epithelial Stem Cells. Cells 2023; 12:2727. [PMID: 38067155 PMCID: PMC10706574 DOI: 10.3390/cells12232727] [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: 08/31/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
The anterior lens epithelium has the ability to differentiate into lens fibres throughout its life. The present study aims to identify and functionally characterize the adult stem cells in the human lens epithelium. Whole mounts of lens epithelium from donor eyes (normal/cataract) were immunostained for SOX2, gap junction protein alpha 1 (GJA1), PAX6, α, β and γ-crystallins, followed by a confocal analysis. The functional property of adult stem cells was analysed by their sphere forming ability using cultured lens epithelial cells from different zones. Based on marker expression, the lens epithelium was divided into four zones: the central zone, characterized by a small population of PAX6+, GJA1-, β-crystallin- and γ-crystallin- cells; the germinative zone, characterized by PAX6+, GJA1+, β-crystallin- and γ-crystallin-; the transitional zone, characterized by PAX6+, GJA1+, β-crystallin+ and γ-crystallin-; and the equatorial zone, characterized by PAX6+/-, GJA1+, β-crystallin+, and γ-crystallin+ cells. The putative lens epithelial stem cells identified as SOX2+ and GJA1 membrane expression negative cells were located only in the central zone (1.89 ± 0.84%). Compared to the other zones, a significant percentage of spheres were identified in the central zone (1.68 ± 1.04%), consistent with the location of the putative adult lens epithelial stem cells. In the cataractous lens, an absence of SOX2 expression and a significant reduction in sphere forming ability (0.33 ± 0.11%) were observed in the central zone. The above findings confirmed the presence of putative stem cells in the central zone of the adult human lens epithelium and indicated their probable association with cataract development.
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Affiliation(s)
- Pandi Saranya
- Department of Immunology and Stem Cell Biology, Aravind Medical Research Foundation, Madurai 625020, India; (P.S.); (V.M.)
- Department of Biotechnology, Aravind Medical Research Foundation—Affiliated to Alagappa University, Karaikudi 630003, India
| | - Madhu Shekhar
- Cataract and IOL Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Madurai 625020, India;
| | - Aravind Haripriya
- Intraocular Lens and Cataract Services, Aravind Eye Hospital, Chennai 600077, India;
| | - Veerappan Muthukkaruppan
- Department of Immunology and Stem Cell Biology, Aravind Medical Research Foundation, Madurai 625020, India; (P.S.); (V.M.)
| | - Chidambaranathan Gowri Priya
- Department of Immunology and Stem Cell Biology, Aravind Medical Research Foundation, Madurai 625020, India; (P.S.); (V.M.)
- Department of Biotechnology, Aravind Medical Research Foundation—Affiliated to Alagappa University, Karaikudi 630003, India
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Wang X, Tan S, Yang S, Liu X, Lei J, Li H. Activation of Sonic Hedgehog Signaling Pathway Regulates Human Trabecular Meshwork Cell Function. J Ocul Pharmacol Ther 2023; 39:430-438. [PMID: 37307020 DOI: 10.1089/jop.2023.0022] [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] [Indexed: 06/13/2023] Open
Abstract
Purpose: To investigate the effects of Sonic hedgehog (Shh) signaling on primary human trabecular meshwork (HTM) cells. Methods: Primary HTM cells were isolated from healthy donors and cultured. Recombinant Shh (rShh) protein and cyclopamine were used to activate and inhibit the Shh signaling pathway, respectively. A cell viability assay was performed to assess the effects of rShh on the activity of primary HTM cells. Functional assessment of cell adhesion and phagocytosis was also performed. The proportion of apoptotic cells was examined using flow cytometry. Fibronectin (FN) and transforming growth factor beta2 (TGF-β2) protein were detected to assess the influence of rShh on the metabolism of the extracellular matrix (ECM). Real-time polymerase chain reaction (RT-PCR) and western blot analyses were used to examine mRNA and protein expression of Shh signaling pathway-associated factors GLI Family Zinc Finger 1 (GLI1) and Suppressor of Fused (SUFU). Results: rShh significantly enhanced primary HTM cell viability at a concentration of 0.5 μg/mL. rShh increased the adhesion and phagocytic abilities of primary HTM cells, and decreased cell apoptosis. FN and TGF-β2 protein expression increased in primary HTM cells treated with rShh. rShh upregulated the transcriptional activity and protein levels of GLI1, and downregulated those of SUFU. Correspondingly, the rShh-induced GLI1 upexpression was partially blocked by pretreatment with the Shh pathway inhibitor cyclopamine at a concentration of 10 μM. Conclusions: Activation of Shh signaling can regulate the function of primary HTM cells through GLI1. Regulation of Shh signaling may be a potential target for attenuating cell damage in glaucoma.
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Affiliation(s)
- Xiaochen Wang
- Department of Ophthalmology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Lab of Ophthalmology, Chongqing Eye Institute, Chongqing Branch of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Sisi Tan
- Department of Ophthalmology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Lab of Ophthalmology, Chongqing Eye Institute, Chongqing Branch of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Shuang Yang
- Department of Ophthalmology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Lab of Ophthalmology, Chongqing Eye Institute, Chongqing Branch of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Xianmao Liu
- Department of Ophthalmology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Lab of Ophthalmology, Chongqing Eye Institute, Chongqing Branch of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Junqin Lei
- Department of Ophthalmology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Lab of Ophthalmology, Chongqing Eye Institute, Chongqing Branch of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Hong Li
- Department of Ophthalmology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Lab of Ophthalmology, Chongqing Eye Institute, Chongqing Branch of National Clinical Research Center for Ocular Diseases, Chongqing, China
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Fu H, Siggs OM, Knight LS, Staffieri SE, Ruddle JB, Birsner AE, Collantes ER, Craig JE, Wiggs JL, D’Amato RJ. Thrombospondin 1 missense alleles induce extracellular matrix protein aggregation and TM dysfunction in congenital glaucoma. J Clin Invest 2022; 132:e156967. [PMID: 36453543 PMCID: PMC9711877 DOI: 10.1172/jci156967] [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: 11/23/2021] [Accepted: 10/11/2022] [Indexed: 12/03/2022] Open
Abstract
Glaucoma is a highly heritable disease that is a leading cause of blindness worldwide. Here, we identified heterozygous thrombospondin 1 (THBS1) missense alleles altering p.Arg1034, a highly evolutionarily conserved amino acid, in 3 unrelated and ethnically diverse families affected by congenital glaucoma, a severe form of glaucoma affecting children. Thbs1R1034C-mutant mice had elevated intraocular pressure (IOP), reduced ocular fluid outflow, and retinal ganglion cell loss. Histology revealed an abundant, abnormal extracellular accumulation of THBS1 with abnormal morphology of juxtacanalicular trabecular meshwork (TM), an ocular tissue critical for aqueous fluid outflow. Functional characterization showed that the THBS1 missense alleles found in affected individuals destabilized the THBS1 C-terminus, causing protein misfolding and extracellular aggregation. Analysis using a range of amino acid substitutions at position R1034 showed that the extent of aggregation was correlated with the change in protein-folding free energy caused by variations in amino acid structure. Extracellular matrix (ECM) proteins, especially fibronectin, which bind to THBS1, also accumulated within THBS1 deposits. These results show that missense variants altering THBS1 p.Arg1034 can cause elevated IOP through a mechanism involving impaired TM fluid outflow in association with accumulation of aggregated THBS1 in the ECM of juxtacanalicular meshwork with altered morphology.
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Affiliation(s)
- Haojie Fu
- Vascular Biology Program, Department of Surgery, Boston Children’s Hospital, Boston, Massachusetts, USA
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
| | - Owen M. Siggs
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
- Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Lachlan S.W. Knight
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
| | - Sandra E. Staffieri
- Centre for Eye Research Australia (CERA), Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- Department of Ophthalmology, University of Melbourne, Department of Surgery, Parkville, Victoria, Australia
- Department of Ophthalmology, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - Jonathan B. Ruddle
- Department of Ophthalmology, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - Amy E. Birsner
- Vascular Biology Program, Department of Surgery, Boston Children’s Hospital, Boston, Massachusetts, USA
| | | | - Jamie E. Craig
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
| | - Janey L. Wiggs
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Department of Ophthalmology, Massachusetts Eye and Ear, Boston, Massachusetts, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Boston, Massachusetts, USA
| | - Robert J. D’Amato
- Vascular Biology Program, Department of Surgery, Boston Children’s Hospital, Boston, Massachusetts, USA
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
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Sundaresan Y, Manivannan LP, Radhakrishnan S, Ramasamy KS, Veerappan M, Chidambaranathan GP. Reduction in trabecular meshwork stem cell content in donor eyes with primary open angle glaucoma. Sci Rep 2021; 11:24518. [PMID: 34972817 PMCID: PMC8720087 DOI: 10.1038/s41598-021-03345-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 11/25/2021] [Indexed: 11/30/2022] Open
Abstract
We previously identified and characterized human trabecular meshwork stem cells (TMSCs) based on high expression of ABCG2/p75 positivity and high nucleus to cytoplasmic ratio. These TMSCs expressing high ABCG2 and p75 were located to the insert region of the human TM. Additionally, we demonstrated an age-related reduction in the TMSC content which was significantly associated with TM cell loss. In continuation, this study was aimed to determine the TMSC content in glaucomatous donor eyes wherein a drastic reduction in TM cellularity has already been reported. Anterior segments from known glaucomatous (n = 6) and age-matched normal (n = 8) donors were dissected into four quadrants. A minimum of three sections from each quadrant were used for histopathological analysis as well as immunostaining. Analysis of hematoxylin and eosin-stained sections from glaucomatous tissues revealed a decrease in total TM cellularity, thickening of trabecular beams, fusion of trabeculae, absence of patent Schlemm's canal compared to age-matched controls. In addition, the TM thickness at various positions of the meshwork and the coronal as well as the meridional diameters of the Schlemm's canal were observed to be significantly reduced in glaucomatous eyes. Further, sections from both the groups were immunostained for universal stem cell marker ABCG2 and neural crest derived stem cell marker p75. The images were acquired using Leica SP8 confocal microscope. Quantification of total TM cellularity based on nuclear counterstain (mean ± SD) using ImageJ identified 69.33 ± 12.77 cells/section in control eyes. In glaucomatous donors, the TM cellularity was found to be reduced significantly to 41.83 ± 9.0 (p = 0.0007). In addition, a reduction in the percentage of TMSCs (cells with high ABCG2 expression and p75 positivity) was evident in glaucomatous donors (0.14 ± 0.17%) compared to age-matched controls (4.73 ± 5.46%) (p = 0.064). Thus, the present study confirmed the significant decline in TM cellularity and a reducing trend in the TMSC content, though this reduction was non-significant in glaucomatous donor eyes. Further studies are essential to elucidate the role of TMSCs in the pathogenesis of primary open angle glaucoma.
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Affiliation(s)
- Yogapriya Sundaresan
- grid.413854.f0000 0004 1767 7755Department of Immunology and Stem Cell Biology, Aravind Medical Research Foundation, Madurai, 625020 Tamil Nadu India
| | - Lakshmi Priya Manivannan
- grid.413854.f0000 0004 1767 7755Department of Immunology and Stem Cell Biology, Aravind Medical Research Foundation, Madurai, 625020 Tamil Nadu India
| | - Shanthi Radhakrishnan
- grid.413854.f0000 0004 1767 7755Department of Pathology, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Madurai, 625020 Tamil Nadu India
| | - Krishnadas Subbiah Ramasamy
- grid.413854.f0000 0004 1767 7755Glaucoma Clinic, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Madurai, 625020 Tamil Nadu India
| | - Muthukkaruppan Veerappan
- grid.413854.f0000 0004 1767 7755Department of Immunology and Stem Cell Biology, Aravind Medical Research Foundation, Madurai, 625020 Tamil Nadu India
| | - Gowri Priya Chidambaranathan
- Department of Immunology and Stem Cell Biology, Aravind Medical Research Foundation, Madurai, 625020, Tamil Nadu, India.
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