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Brinkmeier ML, Wang SQ, Pittman H, Cheung LY, Prasov L. Myelin regulatory factor ( Myrf ) is a critical early regulator of retinal pigment epithelial development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.26.591281. [PMID: 38746430 PMCID: PMC11092522 DOI: 10.1101/2024.04.26.591281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Myelin regulatory factor (Myrf) is a critical transcription factor in early retinal and retinal pigment epithelial development, and human variants in MYRF are a cause for nanophthalmos. Single cell RNA sequencing (scRNAseq) was performed on Myrf conditional knockout mice ( Rx>Cre Myrf fl/fl ) at 3 developmental timepoints. Myrf was expressed specifically in the RPE, and expression was abrogated in Rx>Cre Myrf fl/fl eyes. scRNAseq analysis revealed a loss of RPE cells at all timepoints resulting from cell death. GO-term analysis in the RPE revealed downregulation of melanogenesis and anatomic structure morphogenesis pathways, which were supported by electron microscopy and histologic analysis. Novel structural target genes including Ermn and Upk3b , along with macular degeneration and inherited retinal disease genes were identified as downregulated, and a strong upregulation of TGFß/BMP signaling and effectors was observed. Regulon analysis placed Myrf downstream of Pax6 and Mitf and upstream of Sox10 in RPE differentiation. Together, these results suggest a strong role for Myrf in the RPE maturation by regulating melanogenesis, cell survival, and cell structure, in part acting through suppression of TGFß signaling and activation of Sox10 . SUMMARY STATEMENT Myrf regulates RPE development, melanogenesis, and is important for cell structure and survival, in part through regulation of Ermn , Upk3b and Sox10, and BMP/TGFb signaling.
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Ohguro H, Umetsu A, Sato T, Furuhashi M, Watanabe M. Lipid Metabolism Regulators Are the Possible Determinant for Characteristics of Myopic Human Scleral Stroma Fibroblasts (HSSFs). Int J Mol Sci 2023; 25:501. [PMID: 38203671 PMCID: PMC10778967 DOI: 10.3390/ijms25010501] [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: 11/30/2023] [Revised: 12/25/2023] [Accepted: 12/26/2023] [Indexed: 01/12/2024] Open
Abstract
The purpose of the current investigation was to elucidate what kinds of responsible mechanisms induce elongation of the sclera in myopic eyes. To do this, two-dimensional (2D) cultures of human scleral stromal fibroblasts (HSSFs) obtained from eyes with two different axial length (AL) groups, <26 mm (low AL group, n = 2) and >27 mm (high AL group, n = 3), were subjected to (1) measurements of Seahorse mitochondrial and glycolytic indices to evaluate biological aspects and (2) analysis by RNA sequencing. Extracellular flux analysis revealed that metabolic indices related to mitochondrial and glycolytic functions were higher in the low AL group than in the high AL group, suggesting that metabolic activities of HSSF cells are different depending the degree of AL. Based upon RNA sequencing of these low and high AL groups, the bioinformatic analyses using gene ontology (GO) enrichment analysis and ingenuity pathway analysis (IPA) of differentially expressed genes (DEGs) identified that sterol regulatory element-binding transcription factor 2 (SREBF2) is both a possible upstream regulator and a causal network regulator. Furthermore, SREBF1, insulin-induced gene 1 (INSIG1), and insulin-like growth factor 1 (IGF1) were detected as upstream regulators, and protein tyrosine phosphatase receptor type O (PTPRO) was detected as a causal network regulator. Since those possible regulators were all pivotally involved in lipid metabolisms including fatty acid (FA), triglyceride (TG) and cholesterol (Chol) biosynthesis, the findings reported here indicate that FA, TG and Chol biosynthesis regulation may be responsible mechanisms inducing AL elongation via HSSF.
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Affiliation(s)
- Hiroshi Ohguro
- Department of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Hokkaido, Japan; (H.O.); (A.U.)
| | - Araya Umetsu
- Department of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Hokkaido, Japan; (H.O.); (A.U.)
| | - Tatsuya Sato
- Department of Cardiovascular, Renal and Metabolic Medicine, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Hokkaido, Japan
- Department of Cellular Physiology and Signal Transduction, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Hokkaido, Japan
| | - Masato Furuhashi
- Department of Cardiovascular, Renal and Metabolic Medicine, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Hokkaido, Japan
| | - Megumi Watanabe
- Department of Ophthalmology, School of Medicine, Sapporo Medical University, Sapporo 060-8556, Hokkaido, Japan; (H.O.); (A.U.)
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Mahmud I, Tian G, Wang J, Hutchinson TE, Kim BJ, Awasthee N, Hale S, Meng C, Moore A, Zhao L, Lewis JE, Waddell A, Wu S, Steger JM, Lydon ML, Chait A, Zhao LY, Ding H, Li JL, Purayil HT, Huo Z, Daaka Y, Garrett TJ, Liao D. DAXX drives de novo lipogenesis and contributes to tumorigenesis. Nat Commun 2023; 14:1927. [PMID: 37045819 PMCID: PMC10097704 DOI: 10.1038/s41467-023-37501-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 03/20/2023] [Indexed: 04/14/2023] Open
Abstract
Cancer cells exhibit elevated lipid synthesis. In breast and other cancer types, genes involved in lipid production are highly upregulated, but the mechanisms that control their expression remain poorly understood. Using integrated transcriptomic, lipidomic, and molecular studies, here we report that DAXX is a regulator of oncogenic lipogenesis. DAXX depletion attenuates, while its overexpression enhances, lipogenic gene expression, lipogenesis, and tumor growth. Mechanistically, DAXX interacts with SREBP1 and SREBP2 and activates SREBP-mediated transcription. DAXX associates with lipogenic gene promoters through SREBPs. Underscoring the critical roles for the DAXX-SREBP interaction for lipogenesis, SREBP2 knockdown attenuates tumor growth in cells with DAXX overexpression, and DAXX mutants unable to bind SREBP1/2 have weakened activity in promoting lipogenesis and tumor growth. Remarkably, a DAXX mutant deficient of SUMO-binding fails to activate SREBP1/2 and lipogenesis due to impaired SREBP binding and chromatin recruitment and is defective of stimulating tumorigenesis. Hence, DAXX's SUMO-binding activity is critical to oncogenic lipogenesis. Notably, a peptide corresponding to DAXX's C-terminal SUMO-interacting motif (SIM2) is cell-membrane permeable, disrupts the DAXX-SREBP1/2 interactions, and inhibits lipogenesis and tumor growth. These results establish DAXX as a regulator of lipogenesis and a potential therapeutic target for cancer therapy.
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Affiliation(s)
- Iqbal Mahmud
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
- Southeast Center for Integrated Metabolomics, Clinical and Translational Science Institute, University of Florida, Gainesville, FL, USA
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, USA
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Guimei Tian
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Jia Wang
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
- The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, 450008, Zhengzhou, Henan, China
| | - Tarun E Hutchinson
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Brandon J Kim
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Nikee Awasthee
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Seth Hale
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Chengcheng Meng
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Allison Moore
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Liming Zhao
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Jessica E Lewis
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Aaron Waddell
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Shangtao Wu
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Julia M Steger
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - McKenzie L Lydon
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Aaron Chait
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Lisa Y Zhao
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
- Department of Medicine, University of Florida College of Medicine, Gainesville, FL, USA
| | - Haocheng Ding
- Department of Biostatistics, University of Florida, Gainesville, FL, USA
| | - Jian-Liang Li
- Integrative Bioinformatics, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Hamsa Thayele Purayil
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Zhiguang Huo
- Department of Biostatistics, University of Florida, Gainesville, FL, USA
| | - Yehia Daaka
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Timothy J Garrett
- Southeast Center for Integrated Metabolomics, Clinical and Translational Science Institute, University of Florida, Gainesville, FL, USA
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, USA
| | - Daiqing Liao
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA.
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