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Xu N, Chen Y, Dean KC, Lu X, Liu X, Wang W, Dean DC, Kaplan HJ, Gao L, Dong F, Liu Y. Sphere-Induced Rejuvenation of Swine and Human Müller Glia Is Primarily Caused by Telomere Elongation. Stem Cells 2017; 35:1579-1591. [PMID: 28152565 DOI: 10.1002/stem.2585] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/17/2017] [Accepted: 01/24/2017] [Indexed: 02/01/2023]
Abstract
Müller cells are the major supportive and protective glial cells in the retina with important functions in histogenesis and synaptogenesis during development, and in maintenance of mature neurons as they show to secrete various cytokines and manifest potentials of self-renewal and transdifferentiation into retinal neurons following injury in the vertebrate retinas. The swine retina has a visual streak structure similar to the human macular where cone photoreceptors are highly concentrated, thereby can serve as a better model for studying retinal diseases and for formulating cell-based therapeutics than the rodent retinas. Like most differentiated somatic mammalian cells, the isolated swine and human Müller glia become senescent over passages in culture, which restricts their potential application in basic and clinic researches. Here, we demonstrate that the senescence of swine and human Müller cells is caused by telomere attrition upon multiplications in vitro; and the senescent cells can be rejuvenated by sphere suspension culture. We also provide evidence that sphere-induced extension of telomeres in swine and human Müller glia is achieved by alternative lengthening of telomeres or/and by telomerase activation. Stem Cells 2017;35:1579-1591.
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Affiliation(s)
- Ni Xu
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, USA.,Department of Ophthalmology, Peking Union Medical College Hospital, Beijing, China
| | - Yao Chen
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, USA.,Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China
| | - Kevin C Dean
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Xiaoqin Lu
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Xiao Liu
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, USA.,Department of Ophthalmology, the Second Affiliated Hospital, Central South University Xiangya School of Medicine, Changsha, China
| | - Wei Wang
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Douglas C Dean
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Henry J Kaplan
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Ling Gao
- Department of Ophthalmology, the Second Affiliated Hospital, Central South University Xiangya School of Medicine, Changsha, China
| | - Fangtian Dong
- Department of Ophthalmology, Peking Union Medical College Hospital, Beijing, China
| | - Yongqing Liu
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, USA
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Kim JY, An YM, Park JH. Role of GLTSCR2 in the regulation of telomerase activity and chromosome stability. Mol Med Rep 2016; 14:1697-703. [PMID: 27357325 DOI: 10.3892/mmr.2016.5427] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 01/11/2016] [Indexed: 11/05/2022] Open
Abstract
Telomerase is essential for regulating telomeres, and its activation is a critical step in cellular immortalization and tumorigenesis. The transcriptional activation of human telomerase reverse transcriptase (hTERT) is critical for telomerase expression. Although several transcriptional activators have been identified, factors responsible for enhancing the hTERT promoter remain to be fully elucidated. In the present study, the role of glioma tumor-suppressor candidate region gene 2 (GLTSCR2) in telomerase regulation was analyzed. A doxycyclin-inducible green fluorescent protein (GFP)-tagged GLTSCR2-expressing adenovirus (Ad‑GLT/GFP) was used for the transduction of SK‑Hep‑1 and T98G cancer cells, and normal human umbilical vein endothelial cells. Changes in telomerase activity using telomere repeat amplification protocol assay were assessed, and the gene expression levels of hTERT were then examined. To investigate chromosome instability and senescence, Giemsa and β-galactosidase staining was performed. The results revealed that overexpression of GLTSCR2 significantly increased telomerase activity in the cancer and normal cell lines. This increase was consistent with increases in the protein and mRNA expression levels of hTERT. In luciferase assays, the hTERT promoter was activated by GLTSCR2. Knockdown of GLTSCR2 led to the downregulation of telomerase activity, abnormal nuclear morphology as a marker of chromosome instability, significant suppression of growth rate, alterations in cellular morphology and, eventually, cellular senescence. Taken together, the results of the present study suggested that GLTSCR2 is crucially involved in the positive regulation of telomerase and chromosome stability.
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Affiliation(s)
- Jee-Youn Kim
- Department of Pathology, School of Medicine, Kyung Hee University, Seoul 130‑701, Republic of Korea
| | - Yong-Min An
- Department of Pathology, School of Medicine, Kyung Hee University, Seoul 130‑701, Republic of Korea
| | - Jae-Hoon Park
- Department of Pathology, School of Medicine, Kyung Hee University, Seoul 130‑701, Republic of Korea
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