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VanSlyke JK, Boswell BA, Musil LS. TGFβ overcomes FGF-induced transinhibition of EGFR in lens cells to enable fibrotic secondary cataract. Mol Biol Cell 2024; 35:ar75. [PMID: 38598298 DOI: 10.1091/mbc.e24-01-0040] [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] [Indexed: 04/12/2024] Open
Abstract
To cause vision-disrupting fibrotic secondary cataract (PCO), lens epithelial cells that survive cataract surgery must migrate to the posterior of the lens capsule and differentiate into myofibroblasts. During this process, the cells become exposed to the FGF that diffuses out of the vitreous body. In normal development, such relatively high levels of FGF induce lens epithelial cells to differentiate into lens fiber cells. It has been a mystery as to how lens cells could instead undergo a mutually exclusive cell fate, namely epithelial to myofibroblast transition, in the FGF-rich environment of the posterior capsule. We and others have reported that the ability of TGFβ to induce lens cell fibrosis requires the activity of endogenous ErbBs. We show here that lens fiber-promoting levels of FGF induce desensitization of ErbB1 (EGFR) that involves its phosphorylation on threonine 669 mediated by both ERK and p38 activity. Transinhibition of ErbB1 by FGF is overcome by a time-dependent increase in ErbB1 levels induced by TGFβ, the activation of which is increased after cataract surgery. Our studies provide a rationale for why TGFβ upregulates ErbB1 in lens cells and further support the receptor as a therapeutic target for PCO.
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Affiliation(s)
- Judy K VanSlyke
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239
| | - Bruce A Boswell
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239
| | - Linda S Musil
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239
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2
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Sassine AG, Cakir Y, Della Vecchia L, Ehlers JP. Erdafitinib-associated retinal alterations and rapid onset bilateral white cataracts. Am J Ophthalmol Case Rep 2024; 34:102028. [PMID: 38572298 PMCID: PMC10987836 DOI: 10.1016/j.ajoc.2024.102028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 12/27/2023] [Accepted: 02/16/2024] [Indexed: 04/05/2024] Open
Abstract
Purpose This report aims to highlight the wide spectrum of ophthalmic adverse events associated with erdafitinib, a fibroblast growth factor inhibitor that blocks activation of the mitogen-activated protein kinase kinase (MAPK/MEK) cascade. The purpose of this report is to describe a case of erdafitinib-associated bilateral outer retinal alterations in the MEK-associated retinopathy spectrum and rapid onset bilateral total cataracts following a 20-month course of erdafitinib therapy. Observations A 69 year old male with metastatic bladder cancer presented 47 days following treatment initiation with daily erdafitinib (8-mg) with mild new subretinal fluid and minimal associated subretinal debris in the left eye and accentuation/thickening of the interdigitation zone in the right eye. Over the course of treatment, improvements were noted, particularly with erdafitinib dose reduction. At 20 months, both eyes developed rapidly progressive mature cataracts with significant visual changes, necessitating bilateral cataract extraction. Conclusions and importance The potential stability of moderate outer retinal changes (i.e., ellipsoid zone/interdigitation zone, subretinal fluid) while continuing erdafitinib therapy is highlighted in this report. In addition, the importance of continued ophthalmic surveillance is emphasized given the possible association of anterior segment adverse events with long-term erdafitinib use.
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Affiliation(s)
- Antoine G. Sassine
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Yavuz Cakir
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Lyndsey Della Vecchia
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Justis P. Ehlers
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
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3
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Qiu X, Zhang S, Zhang Y, Cai L, Li D, Lu Y. Reduction of ETV1 is Identified as a Prominent Feature of Age-Related Cataract. Curr Eye Res 2024; 49:496-504. [PMID: 38200696 DOI: 10.1080/02713683.2024.2302545] [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: 12/25/2022] [Accepted: 01/01/2024] [Indexed: 01/12/2024]
Abstract
PURPOSE To identify the inactive genes in cataract lenses and explore their function in lens epithelial cells (LECs). METHODS Lens epithelium samples obtained from both age-related cataract (ARC) patients and normal donors were subjected to two forms of histone H3 immunoprecipitation: H3K9ac and H3K27me3 chromatin immunoprecipitation (ChIP), followed by ChIP-seq. The intersection set of "active genes in normal controls" and "repressed genes in cataract lenses" was identified. To validate the role of a specific gene, ETV1, within this set, quantitative polymerase chain reaction (qPCR), western blot, and immunofluorescence were performed using clinical lens epithelium samples. Small interference RNA (siRNA) was utilized to reduce the mRNA level of ETV1 in cultured LECs. Following this, transwell assay and western blot was performed to examine the migration ability of the cells. Furthermore, RNA-seq analysis was conducted on both cell samples with ETV1 knockdown and control cells. Additionally, the expression level of ETV1 in LECs was examined using qPCR under H2O2 treatment. RESULTS Six genes were identified in the intersection set of "active genes in normal controls" and "repressed genes in ARC lenses". Among these genes, ETV1 showed the most significant fold-change decrease in the cataract samples compared to the control samples. After ETV1 knockdown by siRNA in cultured LECs, reduced cell migration was observed, along with a decrease in the expression of β-Catenin and Vimentin, two specific genes associated with cell migration. In addition, under the oxidative stress induced by H2O2 treatment, the expression level of ETV1 in LECs significantly decreased. CONCLUSIONS Based on the findings of this study, it can be concluded that ETV1 is significantly reduced in human ARC lenses. The repression of ETV1 in ARC lenses appears to contribute to the disrupted differentiation of lens epithelium, which is likely caused by the inhibition of both cell differentiation and migration processes.
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Affiliation(s)
- Xiaodi Qiu
- Eye Institute, Eye & ENT Hospital of Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
- Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Shaohua Zhang
- Eye Institute, Eye & ENT Hospital of Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
- Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Youmeng Zhang
- Department of Stomatology, Eye & ENT Hospital of Fudan University, Shanghai, China
| | - Lei Cai
- Eye Institute, Eye & ENT Hospital of Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
- Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Dan Li
- Eye Institute, Eye & ENT Hospital of Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
- Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Yi Lu
- Eye Institute, Eye & ENT Hospital of Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
- Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
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4
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Camerino M, Chang W, Cvekl A. Analysis of long-range chromatin contacts, compartments and looping between mouse embryonic stem cells, lens epithelium and lens fibers. Epigenetics Chromatin 2024; 17:10. [PMID: 38643244 PMCID: PMC11031936 DOI: 10.1186/s13072-024-00533-x] [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: 11/15/2023] [Accepted: 03/08/2024] [Indexed: 04/22/2024] Open
Abstract
BACKGROUND Nuclear organization of interphase chromosomes involves individual chromosome territories, "open" and "closed" chromatin compartments, topologically associated domains (TADs) and chromatin loops. The DNA- and RNA-binding transcription factor CTCF together with the cohesin complex serve as major organizers of chromatin architecture. Cellular differentiation is driven by temporally and spatially coordinated gene expression that requires chromatin changes of individual loci of various complexities. Lens differentiation represents an advantageous system to probe transcriptional mechanisms underlying tissue-specific gene expression including high transcriptional outputs of individual crystallin genes until the mature lens fiber cells degrade their nuclei. RESULTS Chromatin organization between mouse embryonic stem (ES) cells, newborn (P0.5) lens epithelium and fiber cells were analyzed using Hi-C. Localization of CTCF in both lens chromatins was determined by ChIP-seq and compared with ES cells. Quantitative analyses show major differences between number and size of TADs and chromatin loop size between these three cell types. In depth analyses show similarities between lens samples exemplified by overlaps between compartments A and B. Lens epithelium-specific CTCF peaks are found in mostly methylated genomic regions while lens fiber-specific and shared peaks occur mostly within unmethylated DNA regions. Major differences in TADs and loops are illustrated at the ~ 500 kb Pax6 locus, encoding the critical lens regulatory transcription factor and within a larger ~ 15 Mb WAGR locus, containing Pax6 and other loci linked to human congenital diseases. Lens and ES cell Hi-C data (TADs and loops) together with ATAC-seq, CTCF, H3K27ac, H3K27me3 and ENCODE cis-regulatory sites are shown in detail for the Pax6, Sox1 and Hif1a loci, multiple crystallin genes and other important loci required for lens morphogenesis. The majority of crystallin loci are marked by unexpectedly high CTCF-binding across their transcribed regions. CONCLUSIONS Our study has generated the first data on 3-dimensional (3D) nuclear organization in lens epithelium and lens fibers and directly compared these data with ES cells. These findings generate novel insights into lens-specific transcriptional gene control, open new research avenues to study transcriptional condensates in lens fiber cells, and enable studies of non-coding genetic variants linked to cataract and other lens and ocular abnormalities.
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Affiliation(s)
- Michael Camerino
- The Departments Genetics, Albert Einstein College of Medicine, NY10461, Bronx, USA
| | - William Chang
- Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, NY10461, Bronx, USA
| | - Ales Cvekl
- The Departments Genetics, Albert Einstein College of Medicine, NY10461, Bronx, USA.
- Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, NY10461, Bronx, USA.
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Meric-Bernstam F, Hollebecque A, Furuse J, Oh DY, Bridgewater JA, Shimura M, Anderson B, Hangai N, Wacheck V, Goyal L. Safety Profile and Adverse Event Management for Futibatinib, An Irreversible FGFR1-4 Inhibitor: Pooled Safety Analysis of 469 Patients. Clin Cancer Res 2024; 30:1466-1477. [PMID: 38329716 PMCID: PMC11016890 DOI: 10.1158/1078-0432.ccr-23-2646] [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: 10/16/2023] [Revised: 12/18/2023] [Accepted: 02/05/2024] [Indexed: 02/09/2024]
Abstract
PURPOSE Futibatinib, a covalently-binding inhibitor of fibroblast growth factor receptor (FGFR)1-4 gained approval for the treatment of refractory, advanced intrahepatic cholangiocarcinoma (iCCA) harboring an FGFR2 fusion/other rearrangement. An integrated analysis was performed to evaluate safety and provide guidance on the management of futibatinib-associated adverse events (AEs) in patients with unresectable/metastatic tumors, including iCCA. PATIENTS AND METHODS Data from three global phase I or II studies of futibatinib (NCT02052778; JapicCTI-142552) were pooled. AEs were graded per NCI CTCAE v4.03, where applicable. Safety was analyzed for patients receiving any futibatinib starting dose (overall population) and in those receiving the approved starting dose of 20 mg once every day. RESULTS In total, 469 patients with one of 33 known tumor types were analyzed, including 318 patients who received futibatinib 20 mg every day. AEs of clinical interest (AECI; any grade/grade ≥3) in the overall population included hyperphosphatemia (82%/19%), nail disorders (27%/1%), hepatic AEs (27%/11%), stomatitis (19%/3%), palmar-plantar erythrodysesthesia syndrome (PPES; 13%/3%), rash (9%/0%), retinal disorders (8%/0%), and cataract (4%/1%). Median time to onset of grade ≥3 AECIs ranged from 9 days (hyperphosphatemia) to 125 days (cataract). Grade ≥3 hyperphosphatemia, hepatic AEs, PPES, and nail disorders resolved to grade ≤2 within a median of 7, 7, 8, and 28 days, respectively. Discontinuations due to treatment-related AEs were rare (2%), and no treatment-related deaths occurred. AE management included phosphate-lowering medication and dose adjustments. CONCLUSIONS Futibatinib showed a consistent and manageable safety profile across patients with various tumor types. AECIs were mostly reversible with appropriate clinical management.
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Affiliation(s)
- Funda Meric-Bernstam
- Department of Investigational Cancer Therapeutics, University of Texas MD Anderson Cancer Center, Houston, Texas
| | | | | | - Do-Youn Oh
- Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
- Cancer Research Institute, Integrated Major in Innovative Medical Science, Seoul National University College of Medicine, Seoul, South Korea
| | - John A. Bridgewater
- Department of Medical Oncology, University College London Cancer Institute, London, United Kingdom
| | | | | | | | | | - Lipika Goyal
- Division of Oncology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
- Division of Oncology, Department of Medicine, Stanford Cancer Center, Palo Alto, California
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VanSlyke JK, Boswell BA, Musil LS. Tonic ErbB signaling underlies TGFβ-induced activation of ERK and is required for lens cell epithelial to myofibroblast transition. Mol Biol Cell 2024; 35:ar35. [PMID: 38170570 PMCID: PMC10916858 DOI: 10.1091/mbc.e23-07-0294] [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: 07/31/2023] [Revised: 11/01/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024] Open
Abstract
Fibrosis is a major, but incompletely understood, component of many diseases. The most common vision-disrupting complication of cataract surgery involves differentiation of residual lens cells into myofibroblasts. In serum-free primary cultures of lens epithelial cells (DCDMLs), inhibitors of either ERK or of ErbB signaling prevent TGFβ from upregulating both early (fibronectin) and late (αSMA) markers of myofibroblast differentiation. TGFβ stimulates ERK in DCDMLs within 1.5 h. Kinase inhibitors of ErbBs, but not of several other growth factor receptors in lens cells, reduce phospho ERK to below basal levels in the absence or presence of TGFβ. This effect is attributable to constitutive ErbB activity playing a major role in regulating the basal levels pERK. Additional studies support a model in which TGFβ-generated reactive oxygen species serve to indirectly amplify ERK signaling downstream of tonically active ErbBs to mediate myofibroblast differentiation. ERK activity is in turn essential for expression of ErbB1 and ErbB2, major inducers of ERK signaling. By mechanistically linking TGFβ, ErbB, and ERK signaling to myofibroblast differentiation, our data elucidate a new role for ErbBs in fibrosis and reveal a novel mode by which TGFβ directs lens cell fate.
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Affiliation(s)
- Judy K. VanSlyke
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239
| | - Bruce A. Boswell
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239
| | - Linda S. Musil
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239
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Hsu J, Francis JH, Ahmad S. Ocular toxicities of fibroblast growth factor receptor inhibitors: A review. Surv Ophthalmol 2024; 69:34-41. [PMID: 37777119 DOI: 10.1016/j.survophthal.2023.09.007] [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: 03/12/2023] [Revised: 09/24/2023] [Accepted: 09/25/2023] [Indexed: 10/02/2023]
Abstract
Fibroblast growth factor receptor (FGFR) inhibitors are an emerging class of small molecule targeted cancer drugs with promising therapeutic possibilities for a wide variety of malignancies. While ocular adverse events from FGFR inhibitors are reported in clinical trials, subsequent case studies continue to reveal new toxicities. Disease pathology affecting multiple parts of the eye has been reported, but the ocular surface and the retina are the most commonly encountered areas affected by FGFR inhibitors, manifesting as dry eye and FGFR inhibitor-associated retinopathy, respectively. Corneal thinning and melt is a rare but serious and potentially vision-threatening complication of FGFR inhibitor toxicity. Similarities between toxicities observed from other targeted cancer therapy drugs and FGFR inhibitors may help us understand underlying pathophysiological changes. The management of these adverse events requires close ophthalmologic follow-up and may require discontinuation of the offending agents in some cases.
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Affiliation(s)
- Jerry Hsu
- New York Eye and Ear Infirmary of Mount Sinai, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jasmine H Francis
- Ophthalmic Oncology Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA; Department of Ophthalmology, Weill-Cornell Medical Center, New York, NY, USA
| | - Sumayya Ahmad
- New York Eye and Ear Infirmary of Mount Sinai, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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8
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Brennan L, Disatham J, Menko AS, Kantorow M. Multiomic analysis implicates FOXO4 in genetic regulation of chick lens fiber cell differentiation. Dev Biol 2023; 504:25-37. [PMID: 37722500 PMCID: PMC10843493 DOI: 10.1016/j.ydbio.2023.09.005] [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: 05/15/2023] [Revised: 09/06/2023] [Accepted: 09/14/2023] [Indexed: 09/20/2023]
Abstract
A classic model for identification of novel differentiation mechanisms and pathways is the eye lens that consists of a monolayer of quiescent epithelial cells that are the progenitors of a core of mature fully differentiated fiber cells. The differentiation of lens epithelial cells into fiber cells follows a coordinated program involving cell cycle exit, expression of key structural proteins and the hallmark elimination of organelles to achieve transparency. Although multiple mechanisms and pathways have been identified to play key roles in lens differentiation, the entirety of mechanisms governing lens differentiation remain to be discovered. A previous study established that specific chromatin accessibility changes were directly associated with the expression of essential lens fiber cell genes, suggesting that the activity of transcription factors needed for expression of these genes could be regulated through binding access to the identified chromatin regions. Sequence analysis of the identified chromatin accessible regions revealed enhanced representation of the binding sequence for the transcription factor FOXO4 suggesting a direct role for FOXO4 in expression of these genes. FOXO4 is known to regulate a variety of cellular processes including cellular response to metabolic and oxidative stress, cell cycle withdrawal, and homeostasis, suggesting a previously unidentified role for FOXO4 in the regulation of lens cell differentiation. To further evaluate the role of FOXO4 we employed a multiomics approach to analyze the relationship between genome-wide FOXO4 binding, the differentiation-specific expression of key genes, and chromatin accessibility. To better identify active promoters and enhancers we also examined histone modification through analysis of H3K27ac. Specific methods included CUT&RUN (FOXO4 binding and H3K27ac modification), RNA-seq (differentiation state specific gene expression), and ATAC-seq (chromatin accessibility). CUT&RUN identified 20,966 FOXO4 binding sites and 33,921 H3K27ac marked regions across the lens fiber cell genome. RNA-seq identified 956 genes with significantly greater expression levels in fiber cells compared to epithelial cells (log2FC > 0.7, q < 0.05) and 2548 genes with significantly lower expression levels (log2FC < -0.7, q < 0.05). Integrated analysis identified 1727 differentiation-state specific genes that were nearest neighbors to at least one FOXO4 binding site, including genes encoding lens gap junctions (GJA1, GJA3), lens structural proteins (BFSP1, CRYBB1, ASL1), and genes required for lens transparency (HSF4, NRCAM). Multiomics analysis comparing the identified FOXO4 binding sites in published ATAC-seq data revealed that chromatin accessibility was associated with FOXO4-dependent gene expression during lens differentiation. The results provide evidence for an important requirement for FOXO4 in the regulated expression of key genes required for lens differentiation and link epigenetic regulation of chromatin accessibility and H3K27ac histone modification with the function of FOXO4 in controlling lens gene expression during lens fiber cell differentiation.
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Affiliation(s)
- Lisa Brennan
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Joshua Disatham
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - A Sue Menko
- Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, PA, USA
| | - Marc Kantorow
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA.
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Zhang C, Ye W, Zhao M, Long L, Xia D, Fan Z. MLL1 inhibits the neurogenic potential of SCAPs by interacting with WDR5 and repressing HES1. Int J Oral Sci 2023; 15:48. [PMID: 37852994 PMCID: PMC10584904 DOI: 10.1038/s41368-023-00253-0] [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: 04/19/2023] [Revised: 09/18/2023] [Accepted: 09/25/2023] [Indexed: 10/20/2023] Open
Abstract
Mesenchymal stem cell (MSC)-based therapy has emerged as a promising treatment for spinal cord injury (SCI), but improving the neurogenic potential of MSCs remains a challenge. Mixed lineage leukemia 1 (MLL1), an H3K4me3 methyltransferases, plays a critical role in regulating lineage-specific gene expression and influences neurogenesis. In this study, we investigated the role and mechanism of MLL1 in the neurogenesis of stem cells from apical papilla (SCAPs). We examined the expression of neural markers, and the nerve repair and regeneration ability of SCAPs using dynamic changes in neuron-like cells, immunofluorescence staining, and a SCI model. We employed a coimmunoprecipitation (Co-IP) assay, real-time RT-PCR, microarray analysis, and chromatin immunoprecipitation (ChIP) assay to investigate the molecular mechanism. The results showed that MLL1 knock-down increased the expression of neural markers, including neurogenic differentiation factor (NeuroD), neural cell adhesion molecule (NCAM), tyrosine hydroxylase (TH), βIII-tubulin and Nestin, and promoted neuron-like cell formation in SCAPs. In vivo, a transplantation experiment showed that depletion of MLL 1 in SCAPs can restore motor function in a rat SCI model. MLL1 can combine with WD repeat domain 5 (WDR5) and WDR5 inhibit the expression of neural markers in SCAPs. MLL1 regulates Hairy and enhancer of split 1 (HES1) expression by directly binds to HES1 promoters via regulating H3K4me3 methylation by interacting with WDR5. Additionally, HES1 enhances the expression of neural markers in SCAPs. Our findings demonstrate that MLL1 inhibits the neurogenic potential of SCAPs by interacting with WDR5 and repressing HES1. These results provide a potential therapeutic target for promoting the recovery of motor function in SCI patients.
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Affiliation(s)
- Chen Zhang
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China
- Department of Dental Emergency, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China
| | - Weilong Ye
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China
| | - Mengyao Zhao
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China
| | - Lujue Long
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China
| | - Dengsheng Xia
- Department of Dental Emergency, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China
| | - Zhipeng Fan
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, Beijing, China.
- Beijing Laboratory of Oral Health, Capital Medical University, Beijing, China.
- Research Unit of Tooth Development and Regeneration, Chinese Academy of Medical Sciences, Beijing, China.
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10
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Wishart TFL, Lovicu FJ. Spatiotemporal Localisation of Heparan Sulphate Proteoglycans throughout Mouse Lens Morphogenesis. Cells 2023; 12:1364. [PMID: 37408198 DOI: 10.3390/cells12101364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/05/2023] [Accepted: 05/09/2023] [Indexed: 07/07/2023] Open
Abstract
Heparan sulphate proteoglycans (HSPGs) consist of a core protein decorated with sulphated HS-glycosaminoglycan (GAG) chains. These negatively charged HS-GAG chains rely on the activity of PAPSS synthesising enzymes for their sulfation, which allows them to bind to and regulate the activity of many positively charged HS-binding proteins. HSPGs are found on the surfaces of cells and in the pericellular matrix, where they interact with various components of the cell microenvironment, including growth factors. By binding to and regulating ocular morphogens and growth factors, HSPGs are positioned to orchestrate growth factor-mediated signalling events that are essential for lens epithelial cell proliferation, migration, and lens fibre differentiation. Previous studies have shown that HS sulfation is essential for lens development. Moreover, each of the full-time HSPGs, differentiated by thirteen different core proteins, are differentially localised in a cell-type specific manner with regional differences in the postnatal rat lens. Here, the same thirteen HSPG-associated GAGs and core proteins as well as PAPSS2, are shown to be differentially regulated throughout murine lens development in a spatiotemporal manner. These findings suggest that HS-GAG sulfation is essential for growth factor-induced cellular processes during embryogenesis, and the unique and divergent localisation of different lens HSPG core proteins indicates that different HSPGs likely play specialized roles during lens induction and morphogenesis.
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Affiliation(s)
- Tayler F L Wishart
- Molecular and Cellular Biomedicine, School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Frank J Lovicu
- Molecular and Cellular Biomedicine, School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- Save Sight Institute, The University of Sydney, Sydney, NSW 2006, Australia
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11
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Disatham J, Brennan L, Cvekl A, Kantorow M. Multiomics Analysis Reveals Novel Genetic Determinants for Lens Differentiation, Structure, and Transparency. Biomolecules 2023; 13:693. [PMID: 37189439 PMCID: PMC10136076 DOI: 10.3390/biom13040693] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/13/2023] [Accepted: 04/16/2023] [Indexed: 05/17/2023] Open
Abstract
Recent advances in next-generation sequencing and data analysis have provided new gateways for identification of novel genome-wide genetic determinants governing tissue development and disease. These advances have revolutionized our understanding of cellular differentiation, homeostasis, and specialized function in multiple tissues. Bioinformatic and functional analysis of these genetic determinants and the pathways they regulate have provided a novel basis for the design of functional experiments to answer a wide range of long-sought biological questions. A well-characterized model for the application of these emerging technologies is the development and differentiation of the ocular lens and how individual pathways regulate lens morphogenesis, gene expression, transparency, and refraction. Recent applications of next-generation sequencing analysis on well-characterized chicken and mouse lens differentiation models using a variety of omics techniques including RNA-seq, ATAC-seq, whole-genome bisulfite sequencing (WGBS), chip-seq, and CUT&RUN have revealed a wide range of essential biological pathways and chromatin features governing lens structure and function. Multiomics integration of these data has established new gene functions and cellular processes essential for lens formation, homeostasis, and transparency including the identification of novel transcription control pathways, autophagy remodeling pathways, and signal transduction pathways, among others. This review summarizes recent omics technologies applied to the lens, methods for integrating multiomics data, and how these recent technologies have advanced our understanding ocular biology and function. The approach and analysis are relevant to identifying the features and functional requirements of more complex tissues and disease states.
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Affiliation(s)
- Joshua Disatham
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA; (J.D.); (L.B.)
| | - Lisa Brennan
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA; (J.D.); (L.B.)
| | - Ales Cvekl
- Departments of Ophthalmology and Visual Sciences and Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA;
| | - Marc Kantorow
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA; (J.D.); (L.B.)
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12
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Chen ZX, Jia WN, Sun Y, Chen TH, Zhao ZN, Lan LN, Liu Y, Song LH, Jiang YX. Biallelic ADAMTSL4 variants in a Chinese cohort of congenital ectopia lentis: Implications for genotype-phenotype relationships. Hum Mutat 2022; 43:2141-2152. [PMID: 36208099 DOI: 10.1002/humu.24483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 09/14/2022] [Accepted: 10/03/2022] [Indexed: 01/25/2023]
Abstract
ADAMTSL4 variants are one of the common causes of congenital ectopia lentis (EL), reported ocular comorbidities of which include iris anomalies, cataract, and glaucoma. However, a genotype-phenotype correlation has not been established. Potentially pathogenic ADAMTSL4 variants were screened from a Chinese cohort of congenital EL using panel-based next-generation sequencing followed by multiple bioinformatics analyses. The genotype-phenotype correlation was assessed via a systematic review of ADAMTSL4 variants within our data and those from the literature. A total of 12 variants of ADAMTSL4, including seven frameshift variants, one nonsense variant, two splicing variants, and two missense variants, were found in nine probands. Combing genetic and clinical information from 72 probands in the literature revealed 37 ADAMTSL4 variants known to cause EL, and the ethnic difference was prominent. The lens was inclined to dislocate inferior temporally (22, 27.16%), while the pupil was always located oppositely (9, 81.82%). Several anterior segments anomalies were identified, including ectopia pupillae (15, 18.52%), persistent pupillary membrane (9, 11.10%), poor pupil dilation (4, 30.8%), cataract (13, 24.10%), and glaucoma (8, 13.33%). Genotype-phenotype analysis revealed that truncation variants had higher risks of combined iris anomalies, including either ectopia pupillae or a persistent pupillary membrane (p = 0.007). The data from this study not only extend our knowledge of the ADAMTSL4 variant spectrum but also suggest that deleterious variants of ADAMTSL4 might be associated with severe ocular phenotypes.
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Affiliation(s)
- Ze-Xu Chen
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Wan-Nan Jia
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Yang Sun
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Tian-Hui Chen
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Zhen-Nan Zhao
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Li-Na Lan
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Yan Liu
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Ling-Hao Song
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Yong-Xiang Jiang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University); Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
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13
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Non-canonical Wnt signaling in the eye. Prog Retin Eye Res 2022:101149. [DOI: 10.1016/j.preteyeres.2022.101149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 11/12/2022] [Accepted: 11/17/2022] [Indexed: 11/27/2022]
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14
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Sellitto C, Li L, White TW. Double Deletion of PI3K and PTEN Modifies Lens Postnatal Growth and Homeostasis. Cells 2022; 11:cells11172708. [PMID: 36078116 PMCID: PMC9455000 DOI: 10.3390/cells11172708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/23/2022] [Accepted: 08/27/2022] [Indexed: 11/16/2022] Open
Abstract
We have previously shown that the conditional deletion of either the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K), or its opposing phosphatase, phosphatase and tensin homolog (PTEN), had distinct effects on lens growth and homeostasis. The deletion of p110α reduced the levels of phosphorylated Akt and equatorial epithelial cell proliferation, and resulted in smaller transparent lenses in adult mice. The deletion of PTEN increased levels of phosphorylated Akt, altered lens sodium transport, and caused lens rupture and cataract. Here, we have generated conditional p110α/PTEN double-knockout mice, and evaluated epithelial cell proliferation and lens homeostasis. The double deletion of p110α and PTEN rescued the defect in lens size seen after the single knockout of p110α, but accelerated the lens rupture phenotype seen in PTEN single-knockout mice. Levels of phosphorylated Akt in double-knockout lenses were significantly higher than in wild-type lenses, but not as elevated as those reported for PTEN single-knockout lenses. These results showed that the double deletion of the p110α catalytic subunit of PI3K and its opposing phosphatase, PTEN, exacerbated the rupture defect seen in the single PTEN knockout and alleviated the growth defect observed in the single p110α knockout. Thus, the integrity of the PI3K signaling pathway was absolutely essential for proper lens homeostasis, but not for lens growth.
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15
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Disatham J, Brennan L, Jiao X, Ma Z, Hejtmancik JF, Kantorow M. Changes in DNA methylation hallmark alterations in chromatin accessibility and gene expression for eye lens differentiation. Epigenetics Chromatin 2022; 15:8. [PMID: 35246225 PMCID: PMC8897925 DOI: 10.1186/s13072-022-00440-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/16/2022] [Indexed: 12/13/2022] Open
Abstract
Background Methylation at cytosines (mCG) is a well-known regulator of gene expression, but its requirements for cellular differentiation have yet to be fully elucidated. A well-studied cellular differentiation model system is the eye lens, consisting of a single anterior layer of epithelial cells that migrate laterally and differentiate into a core of fiber cells. Here, we explore the genome-wide relationships between mCG methylation, chromatin accessibility and gene expression during differentiation of eye lens epithelial cells into fiber cells. Results Whole genome bisulfite sequencing identified 7621 genomic loci exhibiting significant differences in mCG levels between lens epithelial and fiber cells. Changes in mCG levels were inversely correlated with the differentiation state-specific expression of 1285 genes preferentially expressed in either lens fiber or lens epithelial cells (Pearson correlation r = − 0.37, p < 1 × 10–42). mCG levels were inversely correlated with chromatin accessibility determined by assay for transposase-accessible sequencing (ATAC-seq) (Pearson correlation r = − 0.86, p < 1 × 10–300). Many of the genes exhibiting altered regions of DNA methylation, chromatin accessibility and gene expression levels in fiber cells relative to epithelial cells are associated with lens fiber cell structure, homeostasis and transparency. These include lens crystallins (CRYBA4, CRYBB1, CRYGN, CRYBB2), lens beaded filament proteins (BFSP1, BFSP2), transcription factors (HSF4, SOX2, HIF1A), and Notch signaling pathway members (NOTCH1, NOTCH2, HEY1, HES5). Analysis of regions exhibiting cell-type specific alterations in DNA methylation revealed an overrepresentation of consensus sequences of multiple transcription factors known to play key roles in lens cell differentiation including HIF1A, SOX2, and the MAF family of transcription factors. Conclusions Collectively, these results link DNA methylation with control of chromatin accessibility and gene expression changes required for eye lens differentiation. The results also point to a role for DNA methylation in the regulation of transcription factors previously identified to be important for lens cell differentiation. Supplementary Information The online version contains supplementary material available at 10.1186/s13072-022-00440-z.
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Affiliation(s)
- Joshua Disatham
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Lisa Brennan
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Xiaodong Jiao
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Zhiwei Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Marc Kantorow
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA.
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16
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Makrides N, Wang Q, Tao C, Schwartz S, Zhang X. Jack of all trades, master of each: the diversity of fibroblast growth factor signalling in eye development. Open Biol 2022; 12:210265. [PMID: 35016551 PMCID: PMC8753161 DOI: 10.1098/rsob.210265] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
A central question in development biology is how a limited set of signalling pathways can instruct unlimited diversity of multicellular organisms. In this review, we use three ocular tissues as models of increasing complexity to present the astounding versatility of fibroblast growth factor (FGF) signalling. In the lacrimal gland, we highlight the specificity of FGF signalling in a one-dimensional model of budding morphogenesis. In the lens, we showcase the dynamics of FGF signalling in altering functional outcomes in a two-dimensional space. In the retina, we present the prolific utilization of FGF signalling from three-dimensional development to homeostasis. These examples not only shed light on the cellular basis for the perfection and complexity of ocular development, but also serve as paradigms for the diversity of FGF signalling.
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Affiliation(s)
- Neoklis Makrides
- Departments of Ophthalmology and Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Qian Wang
- Departments of Ophthalmology and Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Chenqi Tao
- Departments of Ophthalmology and Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Samuel Schwartz
- Departments of Ophthalmology and Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Xin Zhang
- Departments of Ophthalmology and Pathology and Cell Biology, Columbia University, New York, NY, USA
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17
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Wishart TFL, Lovicu FJ. An Atlas of Heparan Sulfate Proteoglycans in the Postnatal Rat Lens. Invest Ophthalmol Vis Sci 2021; 62:5. [PMID: 34730792 PMCID: PMC8572486 DOI: 10.1167/iovs.62.14.5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Purpose The arrangement of lens cells is regulated by ocular growth factors. Although the effects of these inductive molecules on lens cell behavior (proliferation, survival, and fiber differentiation) are well-characterized, the precise mechanisms underlying the regulation of growth factor-mediated signaling in lens remains elusive. Increasing evidence highlights the importance of heparan sulfate proteoglycans (HSPGs) for the signaling regulation of growth factors; however, the identity of the different lens HSPGs and the specific roles they play in lens biology are still unknown. Methods Semiquantitative real-time (RT)‐PCR and immunolabeling were used to characterize the spatial distribution of all known HSPG core proteins and their associated glycosaminoglycans (heparan and chondroitin sulfate) in the postnatal rat lens. Fibroblast growth factor (FGF)-2-treated lens epithelial explants, cultured in the presence of Surfen (an inhibitor of heparan sulfate [HS]-growth factor binding interactions) were used to investigate the requirement for HS in FGF-2-induced proliferation, fiber differentiation, and ERK1/2-signaling. Results The lens expresses all HSPGs. These HSPGs are differentially localized to distinct functional regions of the lens. In vitro, inhibition of HS-sulfation with Surfen blocked FGF-2-mediated ERK1/2-signaling associated with lens epithelial cell proliferation and fiber differentiation, highlighting that these cellular processes are dependent on HS. Conclusions These findings support a requirement for HSPGs in FGF-2 driven lens cell proliferation and fiber differentiation. The identification of specific HSPG core proteins in key functional lens regions, and the divergent expression patterns of closely related HSPGs, suggests that different HSPGs may differentially regulate growth factor signaling networks leading to specific biological events involved in lens growth and maintenance.
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Affiliation(s)
- Tayler F L Wishart
- School of Medical Sciences, The University of Sydney, New South Wales, Australia
| | - Frank J Lovicu
- School of Medical Sciences, The University of Sydney, New South Wales, Australia.,Save Sight Institute, The University of Sydney, New South Wales, Australia
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18
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Cvekl A, Eliscovich C. Crystallin gene expression: Insights from studies of transcriptional bursting. Exp Eye Res 2021; 207:108564. [PMID: 33894228 DOI: 10.1016/j.exer.2021.108564] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/05/2021] [Accepted: 03/22/2021] [Indexed: 01/26/2023]
Abstract
Cellular differentiation is marked by temporally and spatially regulated gene expression. The ocular lens is one of the most powerful mammalian model system since it is composed from only two cell subtypes, called lens epithelial and fiber cells. Lens epithelial cells differentiate into fiber cells through a series of spatially and temporally orchestrated processes, including massive production of crystallins, cellular elongation and the coordinated degradation of nuclei and other organelles. Studies of transcriptional and posttranscriptional gene regulatory mechanisms in lens provide a wide range of opportunities to understand global molecular mechanisms of gene expression as steady-state levels of crystallin mRNAs reach very high levels comparable to globin genes in erythrocytes. Importantly, dysregulation of crystallin gene expression results in lens structural abnormalities and cataracts. The mRNA life cycle is comprised of multiple stages, including transcription, splicing, nuclear export into cytoplasm, stabilization, localization, translation and ultimate decay. In recent years, development of modern mRNA detection methods with single molecule and single cell resolution enabled transformative studies to visualize the mRNA life cycle to generate novel insights into the sequential regulatory mechanisms of gene expression during embryogenesis. This review is focused on recent major advancements in studies of transcriptional bursting in differentiating lens fiber cells, analysis of nascent mRNA expression from bi-directional promoters, transient nuclear accumulation of specific mRNAs, condensation of chromatin prior lens fiber cell denucleation, and outlines future studies to probe the interactions of individual mRNAs with specific RNA-binding proteins (RBPs) in the cytoplasm and regulation of translation and mRNA decay.
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Affiliation(s)
- Ales Cvekl
- Department of Ophthalmology and VIsual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
| | - Carolina Eliscovich
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
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19
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Kumar D, Lim JC, Donaldson PJ. A link between maternal malnutrition and depletion of glutathione in the developing lens: a possible explanation for idiopathic childhood cataract? Clin Exp Optom 2021; 96:523-8. [DOI: 10.1111/cxo.12076] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 11/21/2012] [Accepted: 11/29/2012] [Indexed: 11/30/2022] Open
Affiliation(s)
- Deepa Kumar
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand,
- New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand,
| | - Julie C Lim
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand,
- New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand,
| | - Paul J Donaldson
- New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand,
- School of Medical Sciences, University of Auckland, Auckland, New Zealand,
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20
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Lens fiber cell differentiation occurs independently of fibroblast growth factor receptor signaling in the absence of Pten. Dev Biol 2020; 467:1-13. [PMID: 32858001 DOI: 10.1016/j.ydbio.2020.07.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 07/30/2020] [Accepted: 07/31/2020] [Indexed: 11/21/2022]
Abstract
Fibroblast growth factor receptor (FGFR) signaling patterns multiple tissues in both vertebrates and invertebrates, largely through the activation of intracellular kinases. Recent studies have demonstrated that the phosphatase, PTEN negatively regulates FGFR signaling, such that the loss of PTEN can compensate for reduced FGFR signaling to rescue aspects of normal development. In the developing mouse lens, FGFR signaling promotes cell survival and fiber cell differentiation, and the loss of Pten largely compensates for the loss of Fgfr2 during lens development. To explore this regulatory relationship further, we focused on the phenotypic consequences of Pten loss on lens development and fiber cell differentiation in the absence of all FGFR signaling, both in vivo and in lens epithelial explants. Pten deletion partially rescues primary fiber cell elongation and γ-crystallin accumulation in FGFR-deficient lenses in vivo but fails to rescue cell survival or proliferation. However, in lens epithelial explants, where cells survive without FGFR signaling, Pten deletion rescues vitreous humor-induced lens fiber cell differentiation in the combined absence of Fgfr1, Fgfr2 and Fgfr3. This represents the first evidence that vitreous-initiated signaling cascades, independent of FGFR signaling, can drive mammalian lens fiber cell differentiation, when freed from repression by PTEN.
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21
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Brink PR, Valiunas V, White TW. Lens Connexin Channels Show Differential Permeability to Signaling Molecules. Int J Mol Sci 2020; 21:ijms21186943. [PMID: 32971763 PMCID: PMC7555617 DOI: 10.3390/ijms21186943] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/18/2020] [Accepted: 09/19/2020] [Indexed: 12/12/2022] Open
Abstract
Gap junction channels mediate the direct intercellular passage of small ions as well as larger solutes such as second messengers. A family of proteins called connexins make up the subunits of gap junction channels in chordate animals. Each individual connexin forms channels that exhibit distinct permeability to molecules that influence cellular signaling, such as calcium ions, cyclic nucleotides, or inositol phosphates. In this review, we examine the permeability of connexin channels containing Cx43, Cx46, and Cx50 to signaling molecules and attempt to relate the observed differences in permeability to possible in vivo consequences that were revealed by studies of transgenic animals where these connexin genes have been manipulated. Taken together, these data suggest that differences in the permeability of individual connexin channels to larger solutes like 3',5'-cyclic adenosine monophosphate (cAMP) and inositol 1,4,5-trisphosphate (IP3) could play a role in regulating epithelial cell division, differentiation, and homeostasis in organs like the ocular lens.
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22
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Requirement for Crk and CrkL during postnatal lens development. Biochem Biophys Res Commun 2020; 529:603-607. [DOI: 10.1016/j.bbrc.2020.06.108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 06/20/2020] [Indexed: 01/26/2023]
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23
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Valiunas V, White TW. Connexin43 and connexin50 channels exhibit different permeability to the second messenger inositol triphosphate. Sci Rep 2020; 10:8744. [PMID: 32457413 PMCID: PMC7251084 DOI: 10.1038/s41598-020-65761-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/07/2020] [Indexed: 11/12/2022] Open
Abstract
Gap junction channels made of different connexins have distinct permeability to second messengers, which could affect many cell processes, including lens epithelial cell division. Here, we have compared the permeability of IP3 and Ca2+ through channels made from two connexins, Cx43 and Cx50, that are highly expressed in vertebrate lens epithelial cells. Solute transfer was measured while simultaneously monitoring junctional conductance via dual whole-cell/perforated patch clamp. HeLa cells expressing Cx43 or Cx50 were loaded with Fluo-8, and IP3 or Ca2+ were delivered via patch pipette to one cell of a pair, or to a monolayer while fluorescence intensity changes were recorded. Cx43 channels were permeable to IP3 and Ca2+. Conversely, Cx50 channels were impermeable to IP3, while exhibiting high permeation of Ca2+. Reduced Cx50 permeability to IP3 could play a role in regulating cell division and homeostasis in the lens.
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Affiliation(s)
- Virginijus Valiunas
- The Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA
| | - Thomas W White
- The Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA.
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24
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Garg A, Hannan A, Wang Q, Makrides N, Zhong J, Li H, Yoon S, Mao Y, Zhang X. Etv transcription factors functionally diverge from their upstream FGF signaling in lens development. eLife 2020; 9:e51915. [PMID: 32043969 PMCID: PMC7069720 DOI: 10.7554/elife.51915] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 02/10/2020] [Indexed: 12/12/2022] Open
Abstract
The signal regulated transcription factors (SRTFs) control the ultimate transcriptional output of signaling pathways. Here, we examined a family of FGF-induced SRTFs - Etv1, Etv 4, and Etv 5 - in murine lens development. Contrary to FGF receptor mutants that displayed loss of ERK signaling and defective cell differentiation, Etv deficiency augmented ERK phosphorylation without disrupting the normal lens fiber gene expression. Instead, the transitional zone for lens differentiation was shifted anteriorly as a result of reduced Jag1-Notch signaling. We also showed that Etv proteins suppresses mTOR activity by promoting Tsc2 expression, which is necessary for the nuclei clearance in mature lens. These results revealed the functional divergence between Etv and FGF in lens development, demonstrating that these SRTFs can operate outside the confine of their upstream signaling.
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Affiliation(s)
- Ankur Garg
- Department of Ophthalmology, Columbia UniversityNew YorkUnited States
- Department of Pathology and Cell Biology, Columbia UniversityNew YorkUnited States
| | - Abdul Hannan
- Department of Ophthalmology, Columbia UniversityNew YorkUnited States
- Department of Pathology and Cell Biology, Columbia UniversityNew YorkUnited States
| | - Qian Wang
- Department of Ophthalmology, Columbia UniversityNew YorkUnited States
- Department of Pathology and Cell Biology, Columbia UniversityNew YorkUnited States
| | - Neoklis Makrides
- Department of Ophthalmology, Columbia UniversityNew YorkUnited States
- Department of Pathology and Cell Biology, Columbia UniversityNew YorkUnited States
| | - Jian Zhong
- Burke Neurological Institute and Feil Family Brain and Mind Research Institute, Weill Cornell MedicineWhite PlainsUnited States
| | - Hongge Li
- Department of Ophthalmology, Columbia UniversityNew YorkUnited States
- Department of Pathology and Cell Biology, Columbia UniversityNew YorkUnited States
| | - Sungtae Yoon
- Department of Ophthalmology, Columbia UniversityNew YorkUnited States
- Department of Pathology and Cell Biology, Columbia UniversityNew YorkUnited States
| | - Yingyu Mao
- Department of Ophthalmology, Columbia UniversityNew YorkUnited States
- Department of Pathology and Cell Biology, Columbia UniversityNew YorkUnited States
| | - Xin Zhang
- Department of Ophthalmology, Columbia UniversityNew YorkUnited States
- Department of Pathology and Cell Biology, Columbia UniversityNew YorkUnited States
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25
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Martynova E, Zhao Y, Xie Q, Zheng D, Cvekl A. Transcriptomic analysis and novel insights into lens fibre cell differentiation regulated by Gata3. Open Biol 2019; 9:190220. [PMID: 31847788 PMCID: PMC6936257 DOI: 10.1098/rsob.190220] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Gata3 is a DNA-binding transcription factor involved in cellular differentiation in a variety of tissues including inner ear, hair follicle, kidney, mammary gland and T-cells. In a previous study in 2009, Maeda et al. (Dev. Dyn.238, 2280–2291; doi:10.1002/dvdy.22035) found that Gata3 mutants could be rescued from midgestational lethality by the expression of a Gata3 transgene in sympathoadrenal neuroendocrine cells. The rescued embryos clearly showed multiple defects in lens fibre cell differentiation. To determine whether these defects were truly due to the loss of Gata3 expression in the lens, we generated a lens-specific Gata3 loss-of-function model. Analogous to the previous findings, our Gata3 null embryos showed abnormal regulation of cell cycle exit during lens fibre cell differentiation, marked by reduction in the expression of the cyclin-dependent kinase inhibitors Cdkn1b/p27 and Cdkn1c/p57, and the retention of nuclei accompanied by downregulation of Dnase IIβ. Comparisons of transcriptomes between control and mutated lenses by RNA-Seq revealed dysregulation of lens-specific crystallin genes and intermediate filament protein Bfsp2. Both Cdkn1b/p27 and Cdkn1c/p57 loci are occupied in vivo by Gata3, as well as Prox1 and c-Jun, in lens chromatin. Collectively, our studies suggest that Gata3 regulates lens differentiation through the direct regulation of the Cdkn1b/p27and Cdkn1c/p57 expression, and the direct/or indirect transcriptional control of Bfsp2 and Dnase IIβ.
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Affiliation(s)
- Elena Martynova
- Departments of Ophthalmology and Visual Sciences and Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Yilin Zhao
- Departments of Ophthalmology and Visual Sciences and Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Qing Xie
- Departments of Ophthalmology and Visual Sciences and Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Deyou Zheng
- Departments of Genetics, Neurology, and Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ales Cvekl
- Departments of Ophthalmology and Visual Sciences and Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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26
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Dewi CU, O'Connor MD. Use of Human Pluripotent Stem Cells to Define Initiating Molecular Mechanisms of Cataract for Anti-Cataract Drug Discovery. Cells 2019; 8:E1269. [PMID: 31627438 PMCID: PMC6830331 DOI: 10.3390/cells8101269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/08/2019] [Accepted: 10/15/2019] [Indexed: 01/09/2023] Open
Abstract
Cataract is a leading cause of blindness worldwide. Currently, restoration of vision in cataract patients requires surgical removal of the cataract. Due to the large and increasing number of cataract patients, the annual cost of surgical cataract treatment amounts to billions of dollars. Limited access to functional human lens tissue during the early stages of cataract formation has hampered efforts to develop effective anti-cataract drugs. The ability of human pluripotent stem (PS) cells to make large numbers of normal or diseased human cell types raises the possibility that human PS cells may provide a new avenue for defining the molecular mechanisms responsible for different types of human cataract. Towards this end, methods have been established to differentiate human PS cells into both lens cells and transparent, light-focusing human micro-lenses. Sensitive and quantitative assays to measure light transmittance and focusing ability of human PS cell-derived micro-lenses have also been developed. This review will, therefore, examine how human PS cell-derived lens cells and micro-lenses might provide a new avenue for development of much-needed drugs to treat human cataract.
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Affiliation(s)
- Chitra Umala Dewi
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia.
| | - Michael D O'Connor
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia.
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Valiunas V, Brink PR, White TW. Lens Connexin Channels Have Differential Permeability to the Second Messenger cAMP. Invest Ophthalmol Vis Sci 2019; 60:3821-3829. [PMID: 31529078 PMCID: PMC6750889 DOI: 10.1167/iovs.19-27302] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/13/2019] [Indexed: 01/14/2023] Open
Abstract
Purpose Gap junction channels exhibit connexin specific biophysical properties, including the selective intercellular passage of larger solutes, such as second messengers. Here, we have examined the cyclic nucleotide permeability of the lens connexins, which could influence events like epithelial cell division and differentiation. Methods We compared the cAMP permeability through channels composed of Cx43, Cx46, or Cx50 using simultaneous measurements of junctional conductance and intercellular transfer. For cAMP detection, the recipient cells were transfected with a cAMP sensor gene, the cyclic nucleotide-modulated channel from sea urchin sperm (SpIH). cAMP was introduced via patch pipette into the cell of the pair that did not express SpIH. SpIH-derived currents were recorded from the other cell of a pair that expressed SpIH. cAMP permeability was also directly visualized in transfected cells using a chemically modified fluorescent form of the molecule. Results cAMP transfer was observed for homotypic Cx43 channels over a wide range of junctional conductance. Homotypic Cx46 channels also transferred cAMP, but permeability was reduced compared with Cx43. In contrast, homotypic Cx50 channels exhibited extremely low permeability to cAMP, when compared with either Cx43, or Cx46. Conclusions These data show that channels made from Cx43 and Cx46 result in the intercellular delivery of cAMP in sufficient quantity to activate cyclic nucleotide-modulated channels. The data also suggest that the greatly reduced cAMP permeability of Cx50 channels could play a role in the regulation of cell division in the lens.
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Affiliation(s)
- Virginijus Valiunas
- The Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Peter R. Brink
- The Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Thomas W. White
- The Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
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Disatham J, Chauss D, Gheyas R, Brennan L, Blanco D, Daley L, Menko AS, Kantorow M. Lens differentiation is characterized by stage-specific changes in chromatin accessibility correlating with differentiation state-specific gene expression. Dev Biol 2019; 453:86-104. [PMID: 31136738 DOI: 10.1016/j.ydbio.2019.04.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/16/2019] [Accepted: 04/16/2019] [Indexed: 11/24/2022]
Abstract
Changes in chromatin accessibility regulate the expression of multiple genes by controlling transcription factor access to key gene regulatory sequences. Here, we sought to establish a potential function for altered chromatin accessibility in control of key gene expression events during lens cell differentiation by establishing genome-wide chromatin accessibility maps specific for four distinct stages of lens cell differentiation and correlating specific changes in chromatin accessibility with genome-wide changes in gene expression. ATAC sequencing was employed to generate chromatin accessibility profiles that were correlated with the expression profiles of over 10,000 lens genes obtained by high-throughput RNA sequencing at the same stages of lens cell differentiation. Approximately 90,000 regions of the lens genome exhibited distinct changes in chromatin accessibility at one or more stages of lens differentiation. Over 1000 genes exhibited high Pearson correlation coefficients (r > 0.7) between altered expression levels at specific stages of lens cell differentiation and changes in chromatin accessibility in potential promoter (-7.5kbp/+2.5kbp of the transcriptional start site) and/or other potential cis-regulatory regions ( ±10 kb of the gene body). Analysis of these regions identified consensus binding sequences for multiple transcription factors including members of the TEAD, FOX, and NFAT families of transcription factors as well as HIF1a, RBPJ and IRF1. Functional mapping of genes with high correlations between altered chromatin accessibility and differentiation state-specific gene expression changes identified multiple families of proteins whose expression could be regulated through changes in chromatin accessibility including those governing lens structure (BFSP1,BFSP2), gene expression (Pax-6, Sox 2), translation (TDRD7), cell-cell communication (GJA1), autophagy (FYCO1), signal transduction (SMAD3, EPHA2), and lens transparency (CRYBB1, CRYBA4). These data provide a novel relationship between altered chromatin accessibility and lens differentiation and they identify a wide-variety of lens genes and functions that could be regulated through altered chromatin accessibility. The data also point to a large number of potential DNA regulatory sequences and transcription factors whose functional analysis is likely to provide insight into novel regulatory mechanisms governing the lens differentiation program.
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Affiliation(s)
- Joshua Disatham
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Daniel Chauss
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Rifah Gheyas
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Lisa Brennan
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - David Blanco
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Lauren Daley
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - A Sue Menko
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Marc Kantorow
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA.
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VanSlyke JK, Boswell BA, Musil LS. Fibronectin regulates growth factor signaling and cell differentiation in primary lens cells. J Cell Sci 2018; 131:jcs.217240. [PMID: 30404825 DOI: 10.1242/jcs.217240] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 09/23/2018] [Indexed: 12/30/2022] Open
Abstract
Lens epithelial cells are bound to the lens extracellular matrix capsule, of which laminin is a major component. After cataract surgery, surviving lens epithelial cells are exposed to increased levels of fibronectin, and so we addressed whether fibronectin influences lens cell fate, using DCDML cells as a serum-free primary lens epithelial cell culture system. We found that culturing DCDMLs with plasma-derived fibronectin upregulated canonical TGFβ signaling relative to cells plated on laminin. Fibronectin-exposed cultures also showed increased TGFβ signaling-dependent differentiation into the two cell types responsible for posterior capsule opacification after cataract surgery, namely myofibroblasts and lens fiber cells. Increased TGFβ activity could be identified in the conditioned medium recovered from cells grown on fibronectin. Other experiments showed that plating DCDMLs on fibronectin overcomes the need for BMP in fibroblast growth factor (FGF)-induced lens fiber cell differentiation, a requirement that is restored when endogenous TGFβ signaling is inhibited. These results demonstrate how the TGFβ-fibronectin axis can profoundly affect lens cell fate. This axis represents a novel target for prevention of late-onset posterior capsule opacification, a common but currently intractable complication of cataract surgery.
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Affiliation(s)
- Judy K VanSlyke
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Bruce A Boswell
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Linda S Musil
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239, USA
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Abstract
In this review, we compare and contrast the three different forms of vertebrate lens regeneration: Wolffian lens regeneration, cornea-lens regeneration, and lens regeneration from lens epithelial cells. An examination of the diverse cellular origins of these lenses, their unique phylogenetic distribution, and the underlying molecular mechanisms, suggests that these different forms of lens regeneration evolved independently and utilize neither conserved nor convergent mechanisms to regulate these processes.
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Affiliation(s)
- Jonathan J Henry
- Department of Cell and Developmental Biology, University of Illinois, Urbana, IL
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31
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Cao L, Liu J, Pu J, Collinson JM, Forrester JV, McCaig CD. Endogenous bioelectric currents promote differentiation of the mammalian lens. J Cell Physiol 2017; 233:2202-2212. [PMID: 28661005 PMCID: PMC5724684 DOI: 10.1002/jcp.26074] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 06/28/2017] [Indexed: 12/18/2022]
Abstract
The functional roles of bioelectrical signals (ES) created by the flow of specific ions at the mammalian lens equator are poorly understood. We detected that mature, denucleated lens fibers expressed high levels of the α1 and β1 subunits of Na+/K+‐ATPase (ATP1A1 and ATP1B1 of the sodium pump) and had a hyperpolarized membrane potential difference (Vmem). In contrast, differentiating, nucleated lens fiber cells had little ATP1A1 and ATP1B1 and a depolarized Vmem. Mimicking the natural equatorial ES with an applied electrical field (EF) induced a striking reorientation of lens epithelial cells to lie perpendicular to the direction of the EF. An EF also promoted the expression of β‐crystallin, aquaporin‐0 (AQP0) and the Beaded Filament Structural Protein 2 (BFSP2) in lens epithelial cells (LECs), all of which are hallmarks of differentiation. In addition, applied EF activated the AKT and CDC2 and inhibition of AKT reduced the activation of CDC2. Our results indicate that the endogenous bioelectrical signal at the lens equator promotes differentiation of LECs into denucleated lens fiber cells via depolarization of Vmem. Development of methods and devices of EF application or amplification in vivo may supply a novel treatment for lens diseases and even promote regeneration of a complete new lens following cataract surgery.
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Affiliation(s)
- Lin Cao
- Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
| | - Jie Liu
- Department of Ophthalmology, First Hospital Affiliated to the Chinese PLA General Hospital, Beijing, P.R. China
| | - Jin Pu
- Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
| | - J Martin Collinson
- Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
| | - John V Forrester
- Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
| | - Colin D McCaig
- Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
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Wang D, Wang E, Liu K, Xia CH, Li S, Gong X. Roles of TGFβ and FGF signals during growth and differentiation of mouse lens epithelial cell in vitro. Sci Rep 2017; 7:7274. [PMID: 28779082 PMCID: PMC5544739 DOI: 10.1038/s41598-017-07619-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 06/29/2017] [Indexed: 11/29/2022] Open
Abstract
Transforming growth factor β (TGFβ) and fibroblast growth factor (FGF) signaling pathways play important roles in the proliferation and differentiation of lens epithelial cells (LECs) during development. Low dosage bFGF promotes cell proliferation while high dosage induces differentiation. TGFβ signaling regulates LEC proliferation and differentiation as well, but also promotes epithelial-mesenchymal transitions that lead to cataracts. Thus far, it has been difficult to recapitulate the features of germinative LECs in vitro. Here, we have established a LEC culture protocol that uses SB431542 (SB) compound to inhibit TGFβ/Smad activation, and found that SB treatment promoted mouse LEC proliferation, maintained LECs’ morphology and distinct markers including N-cadherin, c-Maf, Prox1, and αA-, αB-, and β-crystallins. In contrast, low-dosage bFGF was unable to sustain those markers and, combined with SB, altered LECs’ morphology and β-crystallin expression. We further found that Matrigel substrate coatings greatly increased cell proliferation and uniquely affected β-crystallin expression. Cultured LECs retained the ability to differentiate into γ-crystallin-positive lentoids by high-dosage bFGF treatment. Thus, a suppression of TGFβ/Smad signaling in vitro is critical to maintaining characteristic features of mouse LECs, especially expression of the key transcription factors c-Maf and Prox1.
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Affiliation(s)
- Dong Wang
- School of Optometry and Vision Science Program, University of California Berkeley, California, 94720, USA.,Department of Bioengineering, University of California, Berkeley, California, 94720, USA.,Department of Bioengineering, University of California, Los Angeles, California, 90095, USA
| | - Eddie Wang
- School of Optometry and Vision Science Program, University of California Berkeley, California, 94720, USA
| | - Kelsey Liu
- School of Optometry and Vision Science Program, University of California Berkeley, California, 94720, USA
| | - Chun-Hong Xia
- School of Optometry and Vision Science Program, University of California Berkeley, California, 94720, USA
| | - Song Li
- Department of Bioengineering, University of California, Berkeley, California, 94720, USA.,Department of Bioengineering, University of California, Los Angeles, California, 90095, USA.,Department of Medicine, University of California, Los Angeles, California, 90095, USA
| | - Xiaohua Gong
- School of Optometry and Vision Science Program, University of California Berkeley, California, 94720, USA.
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33
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Sellitto C, Li L, Vaghefi E, Donaldson PJ, Lin RZ, White TW. The Phosphoinosotide 3-Kinase Catalytic Subunit p110α is Required for Normal Lens Growth. Invest Ophthalmol Vis Sci 2017; 57:3145-51. [PMID: 27304846 PMCID: PMC4928694 DOI: 10.1167/iovs.16-19607] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purpose Signal transduction pathways influence lens growth, but little is known about the role(s) of the class 1A phosphoinositide 3-kinases (PI3Ks). To further investigate how signaling regulates lens growth, we generated and characterized mice in which the p110α and p110β catalytic subunits of PI3K were conditionally deleted in the mouse lens. Methods Floxed alleles of the catalytic subunits of PI3K were conditionally deleted in the lens by using MLR10-cre transgenic mice. Lenses of age-matched animals were dissected and photographed. Postnatal lenses were fixed, paraffin embedded, sectioned, and stained with hematoxylin-eosin. Cell proliferation was quantified by labeling S-phase cells in intact lenses with 5-ethynyl-2′-deoxyuridine. Protein kinase B (AKT) activation was examined by Western blotting. Results Lens-specific deletion of p110α resulted in a significant reduction of eye and lens size, without compromising lens clarity. Conditional knockout of p110β had no effect on lens size or clarity, and deletion of both the p110α and p110β subunits resulted in a phenotype that resembled the p110α single-knockout phenotype. Levels of activated AKT were decreased more in p110α- than in p110β-deficient lenses. A significant reduction in proliferating cells in the germinative zone was observed on postnatal day 0 in p110α knockout mice, which was temporally correlated with decreased lens volume. Conclusions These data suggest that the class 1A PI3K signaling pathway plays an important role in the regulation of lens size by influencing the extent and spatial location of cell proliferation in the perinatal period.
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Affiliation(s)
- Caterina Sellitto
- Department of Physiology and Biophysics Stony Brook University, Stony Brook, New York, United States
| | - Leping Li
- Department of Physiology and Biophysics Stony Brook University, Stony Brook, New York, United States
| | - Ehsan Vaghefi
- School of Optometry and Vision Science, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Richard Z Lin
- Department of Physiology and Biophysics Stony Brook University, Stony Brook, New York, United States 4Medical Service, Department of Veterans Affairs Medical Center, Northport, New York, United States
| | - Thomas W White
- Department of Physiology and Biophysics Stony Brook University, Stony Brook, New York, United States
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Lim JC, Perwick RD, Li B, Donaldson PJ. Comparison of the expression and spatial localization of glucose transporters in the rat, bovine and human lens. Exp Eye Res 2017. [PMID: 28625822 DOI: 10.1016/j.exer.2017.06.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The energy required to drive lens transparency is derived from the metabolism of glucose. In the lens, the uptake of glucose is likely to involve either facilitative glucose uptake mediated by members of the GLUT family or Na+ dependent glucose uptake via members of the SGLT family, or both. While GLUT1 and GLUT3 have previously been identified in the rat lens, the expression of SGLTs is unknown. Since antibodies directed against the N and C-terminal epitopes of the GLUT and SGLT family are now commercially available, the purpose of this study is to extend our screening of glucose transporters in the rat lens to include the SGLTs and compare the expression profiles of GLUTs and SGLTs in the different regions of the rat, bovine and human lens. Using a combination of reverse transcriptase PCR, western blotting and immunohistochemistry, we have shown that GLUT1 appears to be the predominant glucose transporter in the rat lens since it was expressed in all regions of the lens. In contrast GLUT3, SGLT1 and SGLT2 had more restricted expression patterns and were only found localised to the inner cortex and core regions of the rat lens. GLUT1 was the only transporter found in the epithelium and appears to exist as a full length form in this region, while in differentiating fiber cells; GLUT1 appears to undergo a modification to its N-terminus. Translating our work to bovine and human lenses revealed that GLUT1 is the only glucose transporter expressed in bovine and human lenses. While GLUT1 in the bovine lens appears to be unmodified throughout the entire lens, GLUT1 in human lenses appears to be N-terminally modified in all regions, including the epithelium. Finally, it appears that GLUT1 expression is maintained in all regions of the human lens with increasing age indicating that there is no further regional or age-dependent processing of GLUT1 in the human lens. Taken together, these studies have identified GLUT1 to be the primary transporter that mediates glucose uptake in the rat, bovine and human lens.
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Affiliation(s)
- Julie C Lim
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand.
| | - Rebecca D Perwick
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Bo Li
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand
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Boswell BA, Korol A, West-Mays JA, Musil LS. Dual function of TGFβ in lens epithelial cell fate: implications for secondary cataract. Mol Biol Cell 2017; 28:907-921. [PMID: 28209733 PMCID: PMC5385940 DOI: 10.1091/mbc.e16-12-0865] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/06/2017] [Accepted: 02/07/2017] [Indexed: 12/29/2022] Open
Abstract
The most common vision-disrupting complication of cataract surgery is posterior capsule opacification (PCO; secondary cataract). PCO is caused by residual lens cells undergoing one of two very different cell fates: either transdifferentiating into myofibroblasts or maturing into lens fiber cells. Although TGFβ has been strongly implicated in lens cell fibrosis, the factors responsible for the latter process have not been identified. We show here for the first time that TGFβ can induce purified primary lens epithelial cells within the same culture to undergo differentiation into either lens fiber cells or myofibroblasts. Marker analysis confirmed that the two cell phenotypes were mutually exclusive. Blocking the p38 kinase pathway, either with direct inhibitors of the p38 MAP kinase or a small-molecule therapeutic that also inhibits the activation of p38, prevented TGFβ from inducing epithelial-myofibroblast transition and cell migration but did not prevent fiber cell differentiation. Rapamycin had the converse effect, linking MTOR signaling to induction of fiber cell differentiation by TGFβ. In addition to providing novel potential therapeutic strategies for PCO, our findings extend the so-called TGFβ paradox, in which TGFβ can induce two disparate cell fates, to a new epithelial disease state.
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Affiliation(s)
- Bruce A Boswell
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, OR 97239
| | - Anna Korol
- Department of Pathology and Molecular Medicine, McMaster University Health Science Centre, Hamilton, ON L8N 3Z5, Canada
| | - Judith A West-Mays
- Department of Pathology and Molecular Medicine, McMaster University Health Science Centre, Hamilton, ON L8N 3Z5, Canada
| | - Linda S Musil
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, OR 97239
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36
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Donaldson PJ, Grey AC, Maceo Heilman B, Lim JC, Vaghefi E. The physiological optics of the lens. Prog Retin Eye Res 2017; 56:e1-e24. [DOI: 10.1016/j.preteyeres.2016.09.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 09/09/2016] [Accepted: 09/13/2016] [Indexed: 11/17/2022]
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Thein T, de Melo J, Zibetti C, Clark BS, Juarez F, Blackshaw S. Control of lens development by Lhx2-regulated neuroretinal FGFs. Development 2016; 143:3994-4002. [PMID: 27633990 PMCID: PMC5117141 DOI: 10.1242/dev.137760] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 09/01/2016] [Indexed: 01/07/2023]
Abstract
Fibroblast growth factor (FGF) signaling is an essential regulator of lens epithelial cell proliferation and survival, as well as lens fiber cell differentiation. However, the identities of these FGF factors, their source tissue and the genes that regulate their synthesis are unknown. We have found that Chx10-Cre;Lhx2lox/lox mice, which selectively lack Lhx2 expression in neuroretina from E10.5, showed an early arrest in lens fiber development along with severe microphthalmia. These mutant animals showed reduced expression of multiple neuroretina-expressed FGFs and canonical FGF-regulated genes in neuroretina. When FGF expression was genetically restored in Lhx2-deficient neuroretina of Chx10-Cre;Lhx2lox/lox mice, we observed a partial but nonetheless substantial rescue of the defects in lens cell proliferation, survival and fiber differentiation. These data demonstrate that neuroretinal expression of Lhx2 and neuroretina-derived FGF factors are crucial for lens fiber development in vivo.
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Affiliation(s)
- Thuzar Thein
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, MD 21205, USA
| | - Jimmy de Melo
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, MD 21205, USA
| | - Cristina Zibetti
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, MD 21205, USA
| | - Brian S Clark
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, MD 21205, USA
| | - Felicia Juarez
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, MD 21205, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, MD 21205, USA
- Department of Ophthalmology, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, MD 21205, USA
- Center for Human Systems Biology, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, MD 21205, USA
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, MD 21205, USA
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Pathania M, Wang Y, Simirskii VN, Duncan MK. β1-integrin controls cell fate specification in early lens development. Differentiation 2016; 92:133-147. [PMID: 27596755 PMCID: PMC5159248 DOI: 10.1016/j.diff.2016.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 07/05/2016] [Accepted: 08/09/2016] [Indexed: 02/03/2023]
Abstract
Integrins are heterodimeric cell surface molecules that mediate cell-extracellular matrix (ECM) adhesion, ECM assembly, and regulation of both ECM and growth factor induced signaling. However, the developmental context of these diverse functions is not clear. Loss of β1-integrin from the lens vesicle (mouse E10.5) results in abnormal exit of anterior lens epithelial cells (LECs) from the cell cycle and their aberrant elongation toward the presumptive cornea by E12.5. These cells lose expression of LEC markers and initiate expression of the Maf (also known as c-Maf) and Prox1 transcription factors as well as other lens fiber cell markers. β1-integrin null LECs also upregulate the ERK, AKT and Smad1/5/8 phosphorylation indicative of BMP and FGF signaling. By E14.5, β1-integrin null lenses have undergone a complete conversion of all lens epithelial cells into fiber cells. These data suggest that shortly after lens vesicle closure, β1-integrin blocks inappropriate differentiation of the lens epithelium into fibers, potentially by inhibiting BMP and/or FGF receptor activation. Thus, β1-integrin has an important role in fine-tuning the response of the early lens to the gradient of growth factors that regulate lens fiber cell differentiation.
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Affiliation(s)
- Mallika Pathania
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Yan Wang
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Vladimir N Simirskii
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Melinda K Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA.
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Identification and Ultrastructural Characterization of a Novel Nuclear Degradation Complex in Differentiating Lens Fiber Cells. PLoS One 2016; 11:e0160785. [PMID: 27536868 PMCID: PMC4990417 DOI: 10.1371/journal.pone.0160785] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 07/25/2016] [Indexed: 01/18/2023] Open
Abstract
An unresolved issue in structural biology is how the encapsulated lens removes membranous organelles to carry out its role as a transparent optical element. In this ultrastructural study, we establish a mechanism for nuclear elimination in the developing chick lens during the formation of the organelle-free zone. Day 12-15 chick embryo lenses were examined by high-resolution confocal light microscopy and thin section transmission electron microscopy (TEM) following fixation in 10% formalin and 4% paraformaldehyde, and then processing for confocal or TEM as described previously. Examination of developing fiber cells revealed normal nuclei with dispersed chromatin and clear nucleoli typical of cells in active ribosome production to support protein synthesis. Early signs of nuclear degradation were observed about 300 μm from the lens capsule in Day 15 lenses where the nuclei display irregular nuclear stain and prominent indentations that sometimes contained a previously undescribed macromolecular aggregate attached to the nuclear envelope. We have termed this novel structure the nuclear excisosome. This complex by confocal is closely adherent to the nuclear envelope and by TEM appears to degrade the outer leaflet of the nuclear envelope, then the inner leaflet up to 500 μm depth. The images suggest that the nuclear excisosome separates nuclear membrane proteins from lipids, which then form multilamellar assemblies that stain intensely in confocal and in TEM have 5 nm spacing consistent with pure lipid bilayers. The denuded nucleoplasm then degrades by condensation and loss of structure in the range 600 to 700 μm depth producing pyknotic nuclear remnants. None of these stages display any classic autophagic vesicles or lysosomes associated with nuclei. Uniquely, the origin of the nuclear excisosome is from filopodial-like projections of adjacent lens fiber cells that initially contact, and then appear to fuse with the outer nuclear membrane. These filopodial-like projections appear to be initiated with a clathrin-like coat and driven by an internal actin network. In summary, a specialized cellular organelle, the nuclear excisosome, generated in part by adjacent fiber cells degrades nuclei during fiber cell differentiation and maturation.
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Lee S, Shatadal S, Griep AE. Dlg-1 Interacts With and Regulates the Activities of Fibroblast Growth Factor Receptors and EphA2 in the Mouse Lens. Invest Ophthalmol Vis Sci 2016; 57:707-18. [PMID: 26906157 PMCID: PMC4771194 DOI: 10.1167/iovs.15-17727] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE We previously showed that Discs large-1 (Dlg-1) regulates lens fiber cell structure and the fibroblast growth factor receptor (Fgfr) signaling pathway, a pathway required for fiber cell differentiation. Herein, we investigated the mechanism through which Dlg-1 regulates Fgfr signaling. METHODS Immunofluorescence was used to measure levels of Fgfr1, Fgfr2, and activated Fgfr signaling intermediates, pErk and pAkt, in control and Dlg-1-deficient lenses that were haplodeficient for Fgfr1 or Fgfr2. Immunoblotting was used to measure levels of N-cadherin, EphA2, β-catenin, and tyrosine-phosphorylated EphA2, Fgfr1, Fgfr2, and Fgfr3 in cytoskeletal-associated and cytosolic fractions of control and Dlg-1-deficient lenses. Complex formation between Dlg-1, N-cadherin, β-catenin, Fgfr1, Fgfr2, Fgfr3, and EphA2 was assessed by coimmunoprecipitation. RESULTS Lenses deficient for Dlg-1 and haplodeficient for Fgfr1 or Fgfr2 showed increased levels of Fgfr2 or Fgfr1, respectively. Levels of pErk and pAkt correlated with the level of Fgfr2. N-cadherin was reduced in the cytoskeletal-associated fraction and increased in the cytosolic fraction of Dlg-1-deficient lenses. Dlg-1 complexed with β-catenin, EphA2, Fgfr1, Fgfr2, and Fgfr3. EphA2 complexed with N-cadherin, β-catenin, Fgfr1, Fgfr2, and Fgfr3. Levels of these interactions were altered in Dlg-1-deficient lenses. Loss of Dlg-1 led to changes in Fgfr1, Fgfr2, Fgfr3, and EphA2 levels and to greater changes in the levels of their activation. CONCLUSIONS Dlg-1 complexes with and regulates the activities of EphA2, Fgfr1, Fgfr2, and Fgfr3. As EphA2 contains a Psd95/Dlg/ZO-1 (PDZ) binding motif, whereas Fgfrs do not, we propose that the PDZ protein, Dlg-1, modulates Fgfr signaling through regulation of EphA2.
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Chaffee BR, Hoang TV, Leonard MR, Bruney DG, Wagner BD, Dowd JR, Leone G, Ostrowski MC, Robinson ML. FGFR and PTEN signaling interact during lens development to regulate cell survival. Dev Biol 2016; 410:150-163. [PMID: 26764128 DOI: 10.1016/j.ydbio.2015.12.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 12/31/2015] [Accepted: 12/31/2015] [Indexed: 12/13/2022]
Abstract
Lens epithelial cells express many receptor tyrosine kinases (RTKs) that stimulate PI3K-AKT and RAS-RAF-MEK-ERK intracellular signaling pathways. These pathways ultimately activate the phosphorylation of key cellular transcription factors and other proteins that control proliferation, survival, metabolism, and differentiation in virtually all cells. Among RTKs in the lens, only stimulation of fibroblast growth factor receptors (FGFRs) elicits a lens epithelial cell to fiber cell differentiation response in mammals. Moreover, although the lens expresses three different Fgfr genes, the isolated removal of Fgfr2 at the lens placode stage inhibits both lens cell survival and fiber cell differentiation. Phosphatase and tensin homolog (PTEN), commonly known as a tumor suppressor, inhibits ERK and AKT activation and initiates both apoptotic pathways, and cell cycle arrest. Here, we show that the combined deletion of Fgfr2 and Pten rescues the cell death phenotype associated with Fgfr2 loss alone. Additionally, Pten removal increased AKT and ERK activation, above the levels of controls, in the presence or absence of Fgfr2. However, isolated deletion of Pten failed to stimulate ectopic fiber cell differentiation, and the combined deletion of Pten and Fgfr2 failed to restore differentiation-specific Aquaporin0 and DnaseIIβ expression in the lens fiber cells.
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Affiliation(s)
- Blake R Chaffee
- Department of Biology, Cell Molecular and Structural Biology Graduate Program, Miami University, Oxford, OH, USA
| | - Thanh V Hoang
- Department of Biology, Cell Molecular and Structural Biology Graduate Program, Miami University, Oxford, OH, USA
| | - Melissa R Leonard
- Department of Biology, Cell Molecular and Structural Biology Graduate Program, Miami University, Oxford, OH, USA
| | - Devin G Bruney
- Department of Biology, Cell Molecular and Structural Biology Graduate Program, Miami University, Oxford, OH, USA
| | - Brad D Wagner
- Department of Biology, Cell Molecular and Structural Biology Graduate Program, Miami University, Oxford, OH, USA
| | - Joseph Richard Dowd
- Department of Biology, Cell Molecular and Structural Biology Graduate Program, Miami University, Oxford, OH, USA
| | - Gustavo Leone
- Department of Molecular Virology, Immunology and Medical Genetics, Department of Molecular Genetics, The Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Michael C Ostrowski
- Department of Molecular Virology, Immunology and Medical Genetics, Department of Molecular Genetics, The Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Michael L Robinson
- Department of Biology, Cell Molecular and Structural Biology Graduate Program, Miami University, Oxford, OH, USA.
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Audette DS, Anand D, So T, Rubenstein TB, Lachke SA, Lovicu FJ, Duncan MK. Prox1 and fibroblast growth factor receptors form a novel regulatory loop controlling lens fiber differentiation and gene expression. Development 2015; 143:318-28. [PMID: 26657765 DOI: 10.1242/dev.127860] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/26/2015] [Indexed: 01/19/2023]
Abstract
Lens epithelial cells differentiate into lens fibers (LFs) in response to a fibroblast growth factor (FGF) gradient. This cell fate decision requires the transcription factor Prox1, which has been hypothesized to promote cell cycle exit in differentiating LF cells. However, we find that conditional deletion of Prox1 from mouse lenses results in a failure in LF differentiation despite maintenance of normal cell cycle exit. Instead, RNA-seq demonstrated that Prox1 functions as a global regulator of LF cell gene expression. Intriguingly, Prox1 also controls the expression of fibroblast growth factor receptors (FGFRs) and can bind to their promoters, correlating with decreased downstream signaling through MAPK and AKT in Prox1 mutant lenses. Further, culturing rat lens explants in FGF increased their expression of Prox1, and this was attenuated by the addition of inhibitors of MAPK. Together, these results describe a novel feedback loop required for lens differentiation and morphogenesis, whereby Prox1 and FGFR signaling interact to mediate LF differentiation in response to FGF.
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Affiliation(s)
- Dylan S Audette
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Deepti Anand
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Tammy So
- Discipline of Anatomy & Histology, Bosch Institute & Save Sight Institute, University of Sydney, Sydney, New South Wales 2000, Australia
| | - Troy B Rubenstein
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Salil A Lachke
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE 19716, USA
| | - Frank J Lovicu
- Discipline of Anatomy & Histology, Bosch Institute & Save Sight Institute, University of Sydney, Sydney, New South Wales 2000, Australia
| | - Melinda K Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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Arya P, Rainey MA, Bhattacharyya S, Mohapatra BC, George M, Kuracha MR, Storck MD, Band V, Govindarajan V, Band H. The endocytic recycling regulatory protein EHD1 Is required for ocular lens development. Dev Biol 2015; 408:41-55. [PMID: 26455409 DOI: 10.1016/j.ydbio.2015.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 09/01/2015] [Accepted: 10/06/2015] [Indexed: 12/24/2022]
Abstract
The C-terminal Eps15 homology domain-containing (EHD) proteins play a key role in endocytic recycling, a fundamental cellular process that ensures the return of endocytosed membrane components and receptors back to the cell surface. To define the in vivo biological functions of EHD1, we have generated Ehd1 knockout mice and previously reported a requirement of EHD1 for spermatogenesis. Here, we show that approximately 56% of the Ehd1-null mice displayed gross ocular abnormalities, including anophthalmia, aphakia, microphthalmia and congenital cataracts. Histological characterization of ocular abnormalities showed pleiotropic defects that include a smaller or absent lens, persistence of lens stalk and hyaloid vasculature, and deformed optic cups. To test whether these profound ocular defects resulted from the loss of EHD1 in the lens or in non-lenticular tissues, we deleted the Ehd1 gene selectively in the presumptive lens ectoderm using Le-Cre. Conditional Ehd1 deletion in the lens resulted in developmental defects that included thin epithelial layers, small lenses and absence of corneal endothelium. Ehd1 deletion in the lens also resulted in reduced lens epithelial proliferation, survival and expression of junctional proteins E-cadherin and ZO-1. Finally, Le-Cre-mediated deletion of Ehd1 in the lens led to defects in corneal endothelial differentiation. Taken together, these data reveal a unique role for EHD1 in early lens development and suggest a previously unknown link between the endocytic recycling pathway and regulation of key developmental processes including proliferation, differentiation and morphogenesis.
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Affiliation(s)
- Priyanka Arya
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, 985805 Nebraska Medical Center Omaha, NE 68198-5805, USA; Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA.
| | - Mark A Rainey
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA.
| | - Sohinee Bhattacharyya
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA; Department of Pathology & Microbiology, College of Medicine, University of Nebraska Medical Center, 985900 Nebraska Medical Center Omaha, NE 68198-5900, USA.
| | - Bhopal C Mohapatra
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA; Department of Biochemistry & Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center Omaha, NE 68198-5870, USA.
| | - Manju George
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA.
| | - Murali R Kuracha
- Department of Biomedical Sciences, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA.
| | - Matthew D Storck
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA.
| | - Vimla Band
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, 985805 Nebraska Medical Center Omaha, NE 68198-5805, USA; Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA; Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, 985950 Nebraska Medical Center Omaha, NE 68198-5950, USA.
| | - Venkatesh Govindarajan
- Department of Biomedical Sciences, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA.
| | - Hamid Band
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, 985805 Nebraska Medical Center Omaha, NE 68198-5805, USA; Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA; Department of Pathology & Microbiology, College of Medicine, University of Nebraska Medical Center, 985900 Nebraska Medical Center Omaha, NE 68198-5900, USA; Department of Biochemistry & Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center Omaha, NE 68198-5870, USA; Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, 985950 Nebraska Medical Center Omaha, NE 68198-5950, USA.
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Panda AK, Nandi SK, Chakraborty A, Nagaraj RH, Biswas A. Differential role of arginine mutations on the structure and functions of α-crystallin. Biochim Biophys Acta Gen Subj 2015; 1860:199-210. [PMID: 26080000 DOI: 10.1016/j.bbagen.2015.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 05/22/2015] [Accepted: 06/09/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND α-Crystallin is a major protein of the eye lens in vertebrates. It is composed of two subunits, αA- and αB-crystallin. α-Crystallin is an oligomeric protein having these two subunits in 3:1 ratio. It belongs to small heat shock protein family and exhibits molecular chaperone function, which plays an important role in maintaining the lens transparency. Apart from chaperone function, both subunits also exhibit anti-apoptotic property. Comparison of their primary sequences reveals that αA- and αB-crystallin posses 13 and 14 arginine residues, respectively. Several of them undergo mutations which eventually lead to various eye diseases such as congenital cataract, juvenile cataract, and retinal degeneration. Interestingly, many arginine residues of these subunits are modified during glycation and even some are truncated during aging. All these facts indicate the importance of arginine residues in α-crystallin. SCOPE OF REVIEW In this review, we will emphasize the recent in vitro and in vivo findings related to congenital cataract causing arginine mutations in α-crystallin. MAJOR CONCLUSIONS Congenital cataract causing arginine mutations alters the structure and decreases the chaperone function of α-crystallin. These mutations also affect the lens morphology and phenotypes. Interestingly, non-natural arginine mutations (generated for mimicking the glycation and truncation environment) improve the chaperone function of α-crystallin which may play an important role in maintaining the eye lens transparency during aging. GENERAL SIGNIFICANCE The neutralization of positive charge on the guanidino group of arginine residues is not always detrimental to the functionality of α-crystallin. This article is part of a Special Issue entitled Crystallin Biochemistry in Health and Disease.
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Affiliation(s)
- Alok Kumar Panda
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India
| | - Sandip Kumar Nandi
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India
| | - Ayon Chakraborty
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India
| | - Ram H Nagaraj
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Ashis Biswas
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India.
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Martinez JM, Wang HZ, Lin RZ, Brink PR, White TW. Differential regulation of Connexin50 and Connexin46 by PI3K signaling. FEBS Lett 2015; 589:1340-5. [PMID: 25935417 PMCID: PMC4433579 DOI: 10.1016/j.febslet.2015.04.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/06/2015] [Accepted: 04/16/2015] [Indexed: 01/28/2023]
Abstract
Gap junction channels can modify their activity in response to cell signaling pathways. Here, we demonstrate that Connexin50 (Cx50) coupling, but not Connexin46 (Cx46), increased when co-expressed with a constitutively active p110α subunit of PI3K in Xenopus oocytes. In addition, inhibition of PI3K signaling by blocking p110α, or Akt, significantly decreased gap junctional conductance in Cx50 transfected HeLa cells, with no effect on Cx46. Alterations in coupling levels were not a result of reduced Cx50 unitary conductance, suggesting that changes in the number of active channels were responsible. These data indicate that Cx50 is specifically regulated by the PI3K signaling pathway.
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Affiliation(s)
- Jennifer M Martinez
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Hong-Zhan Wang
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Richard Z Lin
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Peter R Brink
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA
| | - Thomas W White
- The Department of Physiology & Biophysics, Stony Brook University, Stony Brook, NY 11794-8661, USA.
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Lovicu FJ, Shin EH, McAvoy JW. Fibrosis in the lens. Sprouty regulation of TGFβ-signaling prevents lens EMT leading to cataract. Exp Eye Res 2015; 142:92-101. [PMID: 26003864 DOI: 10.1016/j.exer.2015.02.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 01/22/2015] [Accepted: 02/03/2015] [Indexed: 12/22/2022]
Abstract
Cataract is a common age-related condition that is caused by progressive clouding of the normally clear lens. Cataract can be effectively treated by surgery; however, like any surgery, there can be complications and the development of a secondary cataract, known as posterior capsule opacification (PCO), is the most common. PCO is caused by aberrant growth of lens epithelial cells that are left behind in the capsular bag after surgical removal of the fiber mass. An epithelial-to-mesenchymal transition (EMT) is central to fibrotic PCO and forms of fibrotic cataract, including anterior/posterior polar cataracts. Transforming growth factor β (TGFβ) has been shown to induce lens EMT and consequently research has focused on identifying ways of blocking its action. Intriguingly, recent studies in animal models have shown that EMT and cataract developed when a class of negative-feedback regulators, Sprouty (Spry)1 and Spry2, were conditionally deleted from the lens. Members of the Spry family act as general antagonists of the receptor tyrosine kinase (RTK)-mediated MAPK signaling pathway that is involved in many physiological and developmental processes. As the ERK/MAPK signaling pathway is a well established target of Spry proteins, and overexpression of Spry can block aberrant TGFβ-Smad signaling responsible for EMT and anterior subcapsular cataract, this indicates a role for the ERK/MAPK pathway in TGFβ-induced EMT. Given this and other supporting evidence, a case is made for focusing on RTK antagonists, such as Spry, for cataract prevention. In addition, and looking to the future, this review also looks at possibilities for supplanting EMT with normal fiber differentiation and thereby promoting lens regenerative processes after cataract surgery. Whilst it is now known that the epithelial to fiber differentiation process is driven by FGF, little is known about factors that coordinate the precise assembly of fibers into a functional lens. However, recent research provides key insights into an FGF-activated mechanism intrinsic to the lens that involves interactions between the Wnt-Frizzled and Jagged/Notch signaling pathways. This reciprocal epithelial-fiber cell interaction appears to be critical for the assembly and maintenance of the highly ordered three-dimensional architecture that is central to lens function. This information is fundamental to defining the specific conditions and stimuli needed to recapitulate developmental programs and promote regeneration of lens structure and function after cataract surgery.
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Affiliation(s)
- F J Lovicu
- Discipline of Anatomy and Histology, Bosch Institute, School of Medical Sciences, University of Sydney, 2006, NSW, Australia; Save Sight Institute, University of Sydney, Sydney 2001, NSW, Australia.
| | - E H Shin
- Discipline of Anatomy and Histology, Bosch Institute, School of Medical Sciences, University of Sydney, 2006, NSW, Australia
| | - J W McAvoy
- Save Sight Institute, University of Sydney, Sydney 2001, NSW, Australia
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Boswell BA, Musil LS. Synergistic interaction between the fibroblast growth factor and bone morphogenetic protein signaling pathways in lens cells. Mol Biol Cell 2015; 26:2561-72. [PMID: 25947138 PMCID: PMC4571308 DOI: 10.1091/mbc.e15-02-0117] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/01/2015] [Indexed: 12/12/2022] Open
Abstract
Relatively little is known about how receptor tyrosine kinase ligands can positively cooperate with BMP signaling. Primary cultures of lens cells were used to reveal an unprecedented type of cross-talk between the canonical FGF and BMP signaling pathways that regulates lens cell differentiation and intercellular coupling. Fibroblast growth factors (FGFs) play a central role in two processes essential for lens transparency—fiber cell differentiation and gap junction–mediated intercellular communication (GJIC). Using serum-free primary cultures of chick lens epithelial cells (DCDMLs), we investigated how the FGF and bone morphogenetic protein (BMP) signaling pathways positively cooperate to regulate lens development and function. We found that culturing DCDMLs for 6 d with the BMP blocker noggin inhibits the canonical FGF-to-ERK pathway upstream of FRS2 activation and also prevents FGF from stimulating FRS2- and ERK-independent gene expression, indicating that BMP signaling is required at the level of FGF receptors. Other experiments revealed a second type of BMP/FGF interaction by which FGF promotes expression of BMP target genes as well as of BMP4. Together these studies reveal a novel mode of cooperation between the FGF and BMP pathways in which BMP keeps lens cells in an optimally FGF-responsive state and, reciprocally, FGF enhances BMP-mediated gene expression. This interaction provides a mechanistic explanation for why disruption of either FGF or BMP signaling in the lens leads to defects in lens development and function.
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Affiliation(s)
- Bruce A Boswell
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, OR 97239
| | - Linda S Musil
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, OR 97239 )
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Zhang J, Upadhya D, Lu L, Reneker LW. Fibroblast growth factor receptor 2 (FGFR2) is required for corneal epithelial cell proliferation and differentiation during embryonic development. PLoS One 2015; 10:e0117089. [PMID: 25615698 PMCID: PMC4304804 DOI: 10.1371/journal.pone.0117089] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 12/19/2014] [Indexed: 11/19/2022] Open
Abstract
Fibroblast growth factors (FGFs) play important roles in many aspects of embryonic development. During eye development, the lens and corneal epithelium are derived from the same surface ectodermal tissue. FGF receptor (FGFR)-signaling is essential for lens cell differentiation and survival, but its role in corneal development has not been fully investigated. In this study, we examined the corneal defects in Fgfr2 conditional knockout mice in which Cre expression is activated at lens induction stage by Pax6 P0 promoter. The cornea in LeCre, Fgfr2loxP/loxP mice (referred as Fgfr2CKO) was analyzed to assess changes in cell proliferation, differentiation and survival. We found that Fgfr2CKO cornea was much thinner in epithelial and stromal layer when compared to WT cornea. At embryonic day 12.5–13.5 (E12.5–13.5) shortly after the lens vesicle detaches from the overlying surface ectoderm, cell proliferation (judged by labeling indices of Ki-67, BrdU and phospho-histone H3) was significantly reduced in corneal epithelium in Fgfr2CKO mice. At later stage, cell differentiation markers for corneal epithelium and underlying stromal mesenchyme, keratin-12 and keratocan respectively, were not expressed in Fgfr2CKO cornea. Furthermore, Pax6, a transcription factor essential for eye development, was not present in the Fgfr2CKO mutant corneal epithelial at E16.5 but was expressed normally at E12.5, suggesting that FGFR2-signaling is required for maintaining Pax6 expression in this tissue. Interestingly, the role of FGFR2 in corneal epithelial development is independent of ERK1/2-signaling. In contrast to the lens, FGFR2 is not required for cell survival in cornea. This study demonstrates for the first time that FGFR2 plays an essential role in controlling cell proliferation and differentiation, and maintaining Pax6 levels in corneal epithelium via ERK-independent pathways during embryonic development.
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Affiliation(s)
- Jinglin Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Dinesh Upadhya
- Dept. of Ophthalmology, Mason Eye Institute, University of Missouri, Columbia, Missouri, United States of America
| | - Lin Lu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Lixing W. Reneker
- Dept. of Ophthalmology, Mason Eye Institute, University of Missouri, Columbia, Missouri, United States of America
- * E-mail:
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50
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Lens Development and Crystallin Gene Expression. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:129-67. [DOI: 10.1016/bs.pmbts.2015.05.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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