1
|
Cunningham CJ, Choi RB, Bullock WA, Robling AG. Perspective: The current state of Cre driver mouse lines in skeletal research: Challenges and opportunities. Bone 2023; 170:116719. [PMID: 36868507 PMCID: PMC10087282 DOI: 10.1016/j.bone.2023.116719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/15/2023] [Accepted: 02/19/2023] [Indexed: 03/04/2023]
Abstract
The Cre/Lox system has revolutionized the ability of biomedical researchers to ask very specific questions about the function of individual genes in specific cell types at specific times during development and/or disease progression in a variety of animal models. This is true in the skeletal biology field, and numerous Cre driver lines have been created to foster conditional gene manipulation in specific subpopulations of bone cells. However, as our ability to scrutinize these models increases, an increasing number of issues have been identified with most driver lines. All existing skeletal Cre mouse models exhibit problems in one or more of the following three areas: (1) cell type specificity-avoiding Cre expression in unintended cell types; (2) Cre inducibility-improving the dynamic range for Cre in inducible models (negligible Cre activity before induction and high Cre activity after induction); and (3) Cre toxicity-reducing the unwanted biological effects of Cre (beyond loxP recombination) on cellular processes and tissue health. These issues are hampering progress in understanding the biology of skeletal disease and aging, and consequently, identification of reliable therapeutic opportunities. Skeletal Cre models have not advanced technologically in decades despite the availability of improved tools, including multi-promoter-driven expression of permissive or fragmented recombinases, new dimerization systems, and alternative forms of recombinases and DNA sequence targets. We review the current state of skeletal Cre driver lines, and highlight some of the successes, failures, and opportunities to improve fidelity in the skeleton, based on successes pioneered in other areas of biomedical science.
Collapse
Affiliation(s)
- Connor J Cunningham
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Roy B Choi
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Alexander G Robling
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA; Richard L. Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA; Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, Indianapolis, IN, USA; Indiana Center for Musculoskeletal Health, Indianapolis, IN, USA.
| |
Collapse
|
2
|
Zhou Y, Bennett TM, White TW, Shiels A. Charged multivesicular body protein 4b forms complexes with gap junction proteins during lens fiber cell differentiation. FASEB J 2023; 37:e22801. [PMID: 36880430 PMCID: PMC10101236 DOI: 10.1096/fj.202201368rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 03/08/2023]
Abstract
Charged multivesicular body protein 4b (CHMP4B) is a core sub-unit of the endosomal sorting complex required for transport III (ESCRT-III) machinery that serves myriad remodeling and scission processes of biological membranes. Mutation of the human CHMP4B gene underlies rare forms of early-onset lens opacities or cataracts, and CHMP4B is required for lens growth and differentiation in mice. Here, we determine the sub-cellular distribution of CHMP4B in the lens and uncover a novel association with gap junction alpha-3 protein (GJA3) or connexin 46 (Cx46) and GJA8 or Cx50. Immunofluorescence confocal microscopy revealed that CHMP4B localized to cell membranes of elongated fiber cells in the outer cortex of the lens-where large gap junction plaques begin to form-particularly, on the broad faces of these flattened hexagon-like cells in cross-section. Dual immunofluorescence imaging showed that CHMP4B co-localized with gap junction plaques containing Cx46 and/or Cx50. When combined with the in situ proximity ligation assay, immunofluorescence confocal imaging indicated that CHMP4B lay in close physical proximity to Cx46 and Cx50. In Cx46-knockout (Cx46-KO) lenses, CHMP4B-membrane distribution was similar to that of wild-type, whereas, in Cx50-KO lenses, CHMP4B localization to fiber cell membranes was lost. Immunoprecipitation and immunoblotting analyses revealed that CHMP4B formed complexes with Cx46 and Cx50 in vitro. Collectively, our data suggest that CHMP4B forms plasma membrane complexes, either directly and/or indirectly, with gap junction proteins Cx46 and Cx50 that are often associated with "ball-and-socket" double-membrane junctions during lens fiber cell differentiation.
Collapse
Affiliation(s)
- Yuefang Zhou
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Thomas M. Bennett
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Thomas W. White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, USA
| | - Alan Shiels
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| |
Collapse
|
3
|
Wei Z, Hao C, Chen JK, Gan L, Fan X. A tamoxifen-inducible Cre knock-in mouse for lens-specific gene manipulation. Exp Eye Res 2023; 226:109306. [PMID: 36372215 PMCID: PMC9839650 DOI: 10.1016/j.exer.2022.109306] [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: 08/27/2022] [Revised: 11/02/2022] [Accepted: 11/04/2022] [Indexed: 11/13/2022]
Abstract
Mouse models are valuable tools in studying lens biology and biochemistry, and the Cre-loxP system is the most used technology for gene targeting in the lens. However, numerous genes are indispensable in lens development. The conventional knockout method either prevents lens formation or causes simultaneous cataract formation, hindering the studies of their roles in lens structure, growth, metabolism, and cataractogenesis during lens aging. An inducible Cre-loxP mouse line is an excellent way to achieve such a purpose. We established a lens-specific Cre ERT2 knock-in mouse (LCEK), an inducible mouse model for lens-specific gene targeting in a spatiotemporal manner. LCEK mice were created by in-frame infusion of a P2A-CreERT2 at the C-terminus of the last coding exon of the gene alpha A crystallin (Cryaa). LCEK mice express tamoxifen-inducible Cre recombinase uniquely in the lens. Through ROSAmT/mG and two endogenous genes (Gclc and Rbpj) targeting, we found no Cre recombinase leakage in the lens epithelium, but 50-80% leakage was observed in the lens cortex and nucleus. Administration of tamoxifen almost completely abolished target gene expression in both lens epithelium and cortex but only mildly enhanced gene deletion in the lens nucleus. Notably, no overt leakage of Cre activity was detected in developing LCEK lens when bred with mice carrying loxP floxed genes that are essential for lens development. This newly generated LCEK line will be a powerful tool to target genes in the lens for gene functions study in lens aging, posterior capsule opacification (PCO), and other areas requiring precision gene targeting.
Collapse
Affiliation(s)
- Zongbo Wei
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Caili Hao
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Jian-Kang Chen
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Lin Gan
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Xingjun Fan
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, USA.
| |
Collapse
|
4
|
Rashbrook VS, Brash JT, Ruhrberg C. Cre toxicity in mouse models of cardiovascular physiology and disease. NATURE CARDIOVASCULAR RESEARCH 2022; 1:806-816. [PMID: 37692772 PMCID: PMC7615056 DOI: 10.1038/s44161-022-00125-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 07/27/2022] [Indexed: 09/12/2023]
Abstract
The Cre-LoxP system provides a widely used method for studying gene requirements in the mouse as the main mammalian genetic model organism. To define the molecular and cellular mechanisms that underlie cardiovascular development, function and disease, various mouse strains have been engineered that allow Cre-LoxP-mediated gene targeting within specific cell types of the cardiovascular system. Despite the usefulness of this system, evidence is accumulating that Cre activity can have toxic effects in cells, independently of its ability to recombine pairs of engineered LoxP sites in target genes. Here, we have gathered published evidence for Cre toxicity in cells and tissues relevant to cardiovascular biology and provide an overview of mechanisms proposed to underlie Cre toxicity. Based on this knowledge, we propose that each study utilising the Cre-LoxP system to investigate gene function in the cardiovascular system should incorporate appropriate controls to account for Cre toxicity.
Collapse
Affiliation(s)
- Victoria S. Rashbrook
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - James T. Brash
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Christiana Ruhrberg
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| |
Collapse
|
5
|
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.
Collapse
|
6
|
Kasatkina LA, Ma C, Matlashov ME, Vu T, Li M, Kaberniuk AA, Yao J, Verkhusha VV. Optogenetic manipulation and photoacoustic imaging using a near-infrared transgenic mouse model. Nat Commun 2022; 13:2813. [PMID: 35589810 PMCID: PMC9120076 DOI: 10.1038/s41467-022-30547-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 05/06/2022] [Indexed: 12/21/2022] Open
Abstract
Optogenetic manipulation and optical imaging in the near-infrared range allow non-invasive light-control and readout of cellular and organismal processes in deep tissues in vivo. Here, we exploit the advantages of Rhodopseudomonas palustris BphP1 bacterial phytochrome, which incorporates biliverdin chromophore and reversibly photoswitches between the ground (740-800 nm) and activated (620-680 nm) states, to generate a loxP-BphP1 transgenic mouse model. The mouse enables Cre-dependent temporal and spatial targeting of BphP1 expression in vivo. We validate the optogenetic performance of endogenous BphP1, which in the activated state binds its engineered protein partner QPAS1, to trigger gene transcription in primary cells and living mice. We demonstrate photoacoustic tomography of BphP1 expression in different organs, developing embryos, virus-infected tissues and regenerating livers, with the centimeter penetration depth. The transgenic mouse model provides opportunities for both near-infrared optogenetics and photoacoustic imaging in vivo and serves as a source of primary cells and tissues with genomically encoded BphP1.
Collapse
Affiliation(s)
- Ludmila A Kasatkina
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Chenshuo Ma
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Mikhail E Matlashov
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Tri Vu
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Mucong Li
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Andrii A Kaberniuk
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Junjie Yao
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
| | - Vladislav V Verkhusha
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA. .,Medicum, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland.
| |
Collapse
|
7
|
Thompson B, Davidson EA, Chen Y, Orlicky DJ, Thompson DC, Vasiliou V. Oxidative stress induces inflammation of lens cells and triggers immune surveillance of ocular tissues. Chem Biol Interact 2022; 355:109804. [PMID: 35123994 PMCID: PMC9136680 DOI: 10.1016/j.cbi.2022.109804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 12/24/2021] [Accepted: 01/05/2022] [Indexed: 11/03/2022]
Abstract
Recent reports have challenged the notion that the lens is immune-privileged. However, these studies have not fully identified the molecular mechanism(s) that promote immune surveillance of the lens. Using a mouse model of targeted glutathione (GSH) deficiency in ocular surface tissues, we have investigated the role of oxidative stress in upregulating cytokine expression and promoting immune surveillance of the eye. RNA-sequencing of lenses from postnatal day (P) 1-aged Gclcf/f;Le-CreTg/- (KO) and Gclcf/f;Le-Cre-/- control (CON) mice revealed upregulation of many cytokines (e.g., CCL4, GDF15, CSF1) and immune response genes in the lenses of KO mice. The eyes of KO mice had a greater number of cells in the aqueous and vitreous humors at P1, P20 and P50 than age-matched CON and Gclcw/w;Le-CreTg/- (CRE) mice. Histological analyses revealed the presence of innate immune cells (i.e., macrophages, leukocytes) in ocular structures of the KO mice. At P20, the expression of cytokines and ROS content was higher in the lenses of KO mice than in those from age-matched CRE and CON mice, suggesting that oxidative stress may induce cytokine expression. In vitro administration of the oxidant, hydrogen peroxide, and the depletion of GSH (using buthionine sulfoximine (BSO)) in 21EM15 lens epithelial cells induced cytokine expression, an effect that was prevented by co-treatment of the cells with N-acetyl-l-cysteine (NAC), a antioxidant. The in vivo and ex vivo induction of cytokine expression by oxidative stress was associated with the expression of markers of epithelial-to-mesenchymal transition (EMT), α-SMA, in lens cells. Given that EMT of lens epithelial cells causes posterior capsule opacification (PCO), we propose that oxidative stress induces cytokine expression, EMT and the development of PCO in a positive feedback loop. Collectively these data indicate that oxidative stress induces inflammation of lens cells which promotes immune surveillance of ocular structures.
Collapse
Affiliation(s)
- Brian Thompson
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA
| | - Emily A. Davidson
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Ying Chen
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA
| | - David J. Orlicky
- Department of Pathology, Anschutz School of Medicine, University of Colorado, Aurora, CO, USA
| | - David C. Thompson
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA.,Department of Clinical Pharmacy, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO, USA
| | - Vasilis Vasiliou
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA.
| |
Collapse
|
8
|
FUJIMOTO M, KITAMURA H. Application of the colorimetric loop-mediated isothermal amplification (LAMP) technique for genotyping <i>Cre</i>-driver mice. J Vet Med Sci 2022; 84:507-510. [PMID: 35228407 PMCID: PMC9096032 DOI: 10.1292/jvms.21-0658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Cre-loxP system is widely used to investigate the cell-type specific
roles of genes of interest. Cre-driver mice are required for cell-type
specific knockout during the Cre-loxP reaction. To maintain
Cre-driver mouse strains, Polymerase chain reaction (PCR)-oriented
genotyping targeting the Cre gene cassette is usually conducted. In this
study, we instead applied a colorimetric loop-mediated isothermal amplification (LAMP)
method for Cre-genotyping. Among four sets of primers designed by the
in silico program, one set effectively amplified the
Cre cassette of three Cre-driver strains, but not of
C57BL/6 mice. This LAMP-oriented method reduces assay time by less than half compared to
the PCR-based method, and can be carried out using a conventional isothermal incubator.
Applying this LAMP method may accelerate genotyping of Cre-driver
mice.
Collapse
Affiliation(s)
- Masaki FUJIMOTO
- Laboratory of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University
| | - Hiroshi KITAMURA
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University
| |
Collapse
|
9
|
Karnam S, Maddala R, Stiber JA, Rao PV. Drebrin, an actin-binding protein, is required for lens morphogenesis and growth. Dev Dyn 2021; 250:1600-1617. [PMID: 33896079 PMCID: PMC8542647 DOI: 10.1002/dvdy.353] [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: 01/06/2021] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Lens morphogenesis, architecture, and clarity are known to be critically dependent on actin cytoskeleton organization and cell adhesive interactions. There is limited knowledge, however regarding the identity and role of key proteins regulating actin cytoskeletal organization in the lens. This study investigated the role of drebrin, a developmentally regulated actin-binding protein, in mouse lens development by generating and characterizing a conditional knockout (cKO) mouse model using the Cre-LoxP recombination approach. RESULTS Drebrin E, a splice variant of DBN1 is a predominant isoform expressed in the mouse lens and exhibits a maturation-dependent downregulation. Drebrin co-distributes with actin in both epithelium and fibers. Conditional deficiency (both haploinsufficiency and complete absence) of drebrin results in disrupted lens morphogenesis leading to cataract and microphthalmia. The drebrin cKO lens reveals a dramatic decrease in epithelial height and width, E-cadherin, and proliferation, and increased apoptotic cell death and expression of α-smooth muscle actin, together with severely impaired fiber cell organization, polarity, and cell-cell adhesion. CONCLUSIONS This study demonstrates the requirement of drebrin in lens development and growth, with drebrin deficiency leading to impaired lens morphogenesis and microphthalmia.
Collapse
Affiliation(s)
- Shruthi Karnam
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC. USA
| | - Rupalatha Maddala
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC. USA
| | - Jonathan A Stiber
- Department of Medicine, Duke University School of Medicine, Durham, NC. USA
| | - Ponugoti V Rao
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC. USA
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC. USA
| |
Collapse
|
10
|
Shu DY, Lovicu FJ. Insights into Bone Morphogenetic Protein-(BMP-) Signaling in Ocular Lens Biology and Pathology. Cells 2021; 10:cells10102604. [PMID: 34685584 PMCID: PMC8533954 DOI: 10.3390/cells10102604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 01/23/2023] Open
Abstract
Bone morphogenetic proteins (BMPs) are a diverse class of growth factors that belong to the transforming growth factor-beta (TGFβ) superfamily. Although originally discovered to possess osteogenic properties, BMPs have since been identified as critical regulators of many biological processes, including cell-fate determination, cell proliferation, differentiation and morphogenesis, throughout the body. In the ocular lens, BMPs are important in orchestrating fundamental developmental processes such as induction of lens morphogenesis, and specialized differentiation of its fiber cells. Moreover, BMPs have been reported to facilitate regeneration of the lens, as well as abrogate pathological processes such as TGFβ-induced epithelial-mesenchymal transition (EMT) and apoptosis. In this review, we summarize recent insights in this topic and discuss the complexities of BMP-signaling including the role of individual BMP ligands, receptors, extracellular antagonists and cross-talk between canonical and non-canonical BMP-signaling cascades in the lens. By understanding the molecular mechanisms underlying BMP activity, we can advance their potential therapeutic role in cataract prevention and lens regeneration.
Collapse
Affiliation(s)
- Daisy Y. Shu
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA 02114, USA;
| | - Frank J. Lovicu
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- Save Sight Institute, The University of Sydney, Sydney, NSW 2000, Australia
- Correspondence: ; Tel.: +61-2-9351-5170
| |
Collapse
|
11
|
Kiourtis C, Wilczynska A, Nixon C, Clark W, May S, Bird TG. Specificity and off-target effects of AAV8-TBG viral vectors for the manipulation of hepatocellular gene expression in mice. Biol Open 2021; 10:271899. [PMID: 34435198 PMCID: PMC8487635 DOI: 10.1242/bio.058678] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 08/17/2021] [Indexed: 12/12/2022] Open
Abstract
Mice are a widely used pre-clinical model system in large part due to their potential for genetic manipulation. The ability to manipulate gene expression in specific cells under temporal control is a powerful experimental tool. The liver is central to metabolic homeostasis and a site of many diseases, making the targeting of hepatocytes attractive. Adeno-associated virus 8 (AAV8) vectors are valuable instruments for the manipulation of hepatocellular gene expression. However, their off-target effects in mice have not been thoroughly explored. Here, we sought to identify the short-term off-target effects of AAV8 administration in mice. To do this, we injected C57BL/6J wild-type mice with either recombinant AAV8 vectors expressing Cre recombinase or control AAV8 vectors and characterised the changes in general health and in liver physiology, histology and transcriptomics compared to uninjected controls. We observed an acute and transient trend for reduction in homeostatic liver proliferation together with induction of the DNA damage marker γH2AX following AAV8 administration. The latter was enhanced upon Cre recombinase expression by the vector. Furthermore, we observed transcriptional changes in genes involved in circadian rhythm and response to infection. Notably, there were no additional transcriptomic changes upon expression of Cre recombinase by the AAV8 vector. Overall, there was no evidence of liver injury, and only mild T-cell infiltration was observed 14 days following AAV8 infection. These data advance the technique of hepatocellular genome editing through Cre-Lox recombination using Cre expressing AAV vectors, demonstrating their minimal effects on murine physiology and highlight the more subtle off target effects of these systems.
Collapse
Affiliation(s)
- Christos Kiourtis
- Cancer Research UK Beatson Institute, Glasgow G61 1BD, UK.,Institute of Cancer Sciences, University of Glasgow, Glasgow G61 1QH, United Kingdom
| | - Ania Wilczynska
- Cancer Research UK Beatson Institute, Glasgow G61 1BD, UK.,Institute of Cancer Sciences, University of Glasgow, Glasgow G61 1QH, United Kingdom
| | - Colin Nixon
- Cancer Research UK Beatson Institute, Glasgow G61 1BD, UK
| | - William Clark
- Cancer Research UK Beatson Institute, Glasgow G61 1BD, UK
| | - Stephanie May
- Cancer Research UK Beatson Institute, Glasgow G61 1BD, UK
| | - Thomas G Bird
- Cancer Research UK Beatson Institute, Glasgow G61 1BD, UK.,MRC Centre for Inflammation Research, The Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH164TJ, UK
| |
Collapse
|
12
|
Thompson B, Chen Y, Davidson EA, Garcia-Milian R, Golla JP, Apostolopoulos N, Orlicky DJ, Schey K, Thompson DC, Vasiliou V. Impaired GSH biosynthesis disrupts eye development, lens morphogenesis and PAX6 function. Ocul Surf 2021; 22:190-203. [PMID: 34425299 DOI: 10.1016/j.jtos.2021.08.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/29/2021] [Accepted: 08/16/2021] [Indexed: 12/14/2022]
Abstract
PURPOSE The purpose of this study was to elucidate the role and molecular consequences of impaired glutathione (GSH) biosynthesis on eye development. METHODS GSH biosynthesis was impaired in surface ectoderm-derived ocular tissues by crossing Gclcf/f mice with hemizygous Le-Cre transgenic mice to produce Gclcf/f/Le-CreTg/- (KO) mice. Control mice included Gclcf/fand Gclcwt/wt/Le-CreTg/- mice (CRE). Eyes from all mice (at various stages of eye development) were subjected to histological, immunohistochemical, Western blot, RT-qPCR, RNA-seq, and subsequent Gene Ontology, Ingenuity Pathway Analysis and TRANSFAC analyses. PAX6 transactivation activity was studied using a luciferase reporter assay in HEK293T cells depleted of GSH using buthionine sulfoximine (BSO). RESULTS Deletion of Gclc diminished GSH levels, increased reactive oxygen species (ROS), and caused an overt microphthalmia phenotype characterized by malformation of the cornea, iris, lens, and retina that is distinct from and much more profound than the one observed in CRE mice. In addition, only the lenses of KO mice displayed reduced crystallin (α, β), PITX3 and Foxe3 expression. RNA-seq analyses at postnatal day 1 revealed 1552 differentially expressed genes (DEGs) in the lenses of KO mice relative to those from Gclcf/f mice, with Crystallin and lens fiber cell identity genes being downregulated while lens epithelial cell identity and immune response genes were upregulated. Bioinformatic analysis of the DEGs implicated PAX6 as a key upstream regulator. PAX6 transactivation activity was impaired in BSO-treated HEK293T cells. CONCLUSIONS These data suggest that impaired ocular GSH biosynthesis may disrupt eye development and PAX6 function.
Collapse
Affiliation(s)
- Brian Thompson
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA
| | - Ying Chen
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA
| | - Emily A Davidson
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA; Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Rolando Garcia-Milian
- Bioinformatics Support Program, Cushing/Whitney Medical Library, Yale School of Medicine, New Haven, CT, USA
| | - Jaya Prakash Golla
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA; Department of Medicine, Yale University School of Medicine, New Haven, CT, USA; Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | | | - David J Orlicky
- Department of Pathology, Anschutz School of Medicine, University of Colorado, Aurora, CO, USA
| | - Kevin Schey
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - David C Thompson
- Department of Clinical Pharmacy, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO, USA
| | - Vasilis Vasiliou
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA.
| |
Collapse
|
13
|
Long Y, Cech TR. Targeted mutagenesis in human iPSCs using CRISPR genome-editing tools. Methods 2021; 191:44-58. [PMID: 33444739 DOI: 10.1016/j.ymeth.2021.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/27/2020] [Accepted: 01/02/2021] [Indexed: 12/27/2022] Open
Abstract
Mutagenesis studies have rapidly evolved in the era of CRISPR genome editing. Precise manipulation of genes in human induced pluripotent stem cells (iPSCs) allows biomedical researchers to study the physiological functions of individual genes during development. Furthermore, such genetic manipulation applied to patient-specific iPSCs allows disease modeling, drug screening and development of therapeutics. Although various genome-editing methods have been developed to introduce or remove mutations in human iPSCs, comprehensive strategic designs taking account of the potential side effects of CRISPR editing are needed. Here we present several novel and highly efficient strategies to introduce point mutations, insertions and deletions in human iPSCs, including step-by-step experimental protocols. These approaches involve the application of drug selection for effortless clone screening and the generation of a wild type control strain along with the mutant. We also present several examples of application of these strategies in human iPSCs and show that they are highly efficient and could be applied to other cell types.
Collapse
Affiliation(s)
- Yicheng Long
- Department of Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80309, United States
| | - Thomas R Cech
- Department of Biochemistry and BioFrontiers Institute, University of Colorado, Boulder, CO 80309, United States; Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, United States.
| |
Collapse
|
14
|
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.
Collapse
|
15
|
Menuchin-Lasowski Y, Dagan B, Conidi A, Cohen-Gulkar M, David A, Ehrlich M, Giladi PO, Clark BS, Blackshaw S, Shapira K, Huylebroeck D, Henis YI, Ashery-Padan R. Zeb2 regulates the balance between retinal interneurons and Müller glia by inhibition of BMP-Smad signaling. Dev Biol 2020; 468:80-92. [PMID: 32950463 DOI: 10.1016/j.ydbio.2020.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 08/24/2020] [Accepted: 09/10/2020] [Indexed: 12/27/2022]
Abstract
The interplay between signaling molecules and transcription factors during retinal development is key to controlling the correct number of retinal cell types. Zeb2 (Sip1) is a zinc-finger multidomain transcription factor that plays multiple roles in central and peripheral nervous system development. Haploinsufficiency of ZEB2 causes Mowat-Wilson syndrome, a congenital disease characterized by intellectual disability, epilepsy and Hirschsprung disease. In the developing retina, Zeb2 is required for generation of horizontal cells and the correct number of interneurons; however, its potential function in controlling gliogenic versus neurogenic decisions remains unresolved. Here we present cellular and molecular evidence of the inhibition of Müller glia cell fate by Zeb2 in late stages of retinogenesis. Unbiased transcriptomic profiling of control and Zeb2-deficient early-postnatal retina revealed that Zeb2 functions in inhibiting Id1/2/4 and Hes1 gene expression. These neural progenitor factors normally inhibit neural differentiation and promote Müller glia cell fate. Chromatin immunoprecipitation (ChIP) supported direct regulation of Id1 by Zeb2 in the postnatal retina. Reporter assays and ChIP analyses in differentiating neural progenitors provided further evidence that Zeb2 inhibits Id1 through inhibition of Smad-mediated activation of Id1 transcription. Together, the results suggest that Zeb2 promotes the timely differentiation of retinal interneurons at least in part by repressing BMP-Smad/Notch target genes that inhibit neurogenesis. These findings show that Zeb2 integrates extrinsic cues to regulate the balance between neuronal and glial cell types in the developing murine retina.
Collapse
Affiliation(s)
- Yotam Menuchin-Lasowski
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Bar Dagan
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Andrea Conidi
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam 3015 CN, the Netherlands
| | - Mazal Cohen-Gulkar
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ahuvit David
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Marcelo Ehrlich
- Shumins School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Pazit Oren Giladi
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Brian S Clark
- John F Hardesty, MD Department of Ophthalmology and Visual Sciences and Department of Developmental Biology, Washington University, St. Louis, MO 63110, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Baltimore, MD 21205, USA; Department of Ophthalmology, Baltimore, MD 21205, USA; Department of Neurology, Baltimore, MD 21205, USA; Center for Human Systems Biology, Baltimore, MD 21205, USA; Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Keren Shapira
- Shumins School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Danny Huylebroeck
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam 3015 CN, the Netherlands; Department of Development and Regeneration, KU Leuven, Leuven 3000, Belgium
| | - Yoav I Henis
- Shumins School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ruth Ashery-Padan
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
| |
Collapse
|
16
|
Lavoie A, Liu BH. Canine Adenovirus 2: A Natural Choice for Brain Circuit Dissection. Front Mol Neurosci 2020; 13:9. [PMID: 32174812 PMCID: PMC7056889 DOI: 10.3389/fnmol.2020.00009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/14/2020] [Indexed: 12/15/2022] Open
Abstract
Canine adenovirus-2 (CAV) is a canine pathogen that has been used in a variety of applications, from vaccines against more infectious strains of CAV to treatments for neurological disorders. With recent engineering, CAV has become a natural choice for neuroscientists dissecting the connectivity and function of brain circuits. Specifically, as a reliable genetic vector with minimal immunogenic and cytotoxic reactivity, CAV has been used for the retrograde transduction of various types of projection neurons. Consequently, CAV is particularly useful when studying the anatomy and functions of long-range projections. Moreover, combining CAV with conditional expression and transsynaptic tracing results in the ability to study circuits with cell- and/or projection-type specificity. Lastly, with the well-documented knowledge of viral transduction, new innovations have been developed to increase the transduction efficiency of CAV and circumvent its tropism, expanding the potential of CAV for circuit analysis.
Collapse
Affiliation(s)
- Andréanne Lavoie
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Bao-Hua Liu
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
17
|
Nguyen WNT, Jacobsen EA, Finney CAM, Colarusso P, Patel KD. Intravital imaging of eosinophils: Unwrapping the enigma. J Leukoc Biol 2020; 108:83-91. [PMID: 32170880 DOI: 10.1002/jlb.3hr0220-396r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 02/16/2020] [Accepted: 02/20/2020] [Indexed: 12/12/2022] Open
Abstract
Eosinophils are traditionally associated with allergic and parasitic inflammation. More recently, eosinophils have also been shown to have roles in diverse processes including development, intestinal health, thymic selection, and B-cell survival with the majority of these insights being derived from murine models and in vitro assays. Despite this, tools to measure the dynamic activity of eosinophils in situ have been lacking. Intravital microscopy is a powerful tool that enables direct visualization of leukocytes and their dynamic behavior in real-time in a wide range of processes in both health and disease. Until recently eosinophil researchers have not been able to take full advantage of this technology due to a lack of tools such as genetically encoded reporter mice. This mini-review examines the history of intravital microscopy with a focus on eosinophils. The development and use of eosinophil-specific Cre (EoCre) mice to create GFP and tdTomato fluorescent reporter animals is also described. Genetically encoded eosinophil reporter mice combined with intravital microscopy provide a powerful tool to add to the toolbox of technologies that will help us unravel the mysteries still surrounding this cell.
Collapse
Affiliation(s)
- William N T Nguyen
- Departments of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Elizabeth A Jacobsen
- Division of Allergy and Clinical Immunology, Mayo Clinic Arizona, Scottsdale, Arizona, USA
| | - Constance A M Finney
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
| | - Pina Colarusso
- Departments of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Kamala D Patel
- Departments of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Biochemistry and Molecular Biology, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
Padula SL, Anand D, Hoang TV, Chaffee BR, Liu L, Liang C, Lachke SA, Robinson ML. High-throughput transcriptome analysis reveals that the loss of Pten activates a novel NKX6-1/RASGRP1 regulatory module to rescue microphthalmia caused by Fgfr2-deficient lenses. Hum Genet 2019; 138:1391-1407. [PMID: 31691004 DOI: 10.1007/s00439-019-02084-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/28/2019] [Indexed: 01/17/2023]
Abstract
FGFR signaling is critical to development and disease pathogenesis, initiating phosphorylation-driven signaling cascades, notably the RAS-RAF-MEK-ERK and PI3 K-AKT cascades. PTEN antagonizes FGFR signaling by reducing AKT and ERK activation. Mouse lenses lacking FGFR2 exhibit microphakia and reduced ERK and AKT phosphorylation, widespread apoptosis, and defective lens fiber cell differentiation. In contrast, simultaneous deletion of both Fgfr2 and Pten restores ERK and AKT activation levels as well as lens size, cell survival and aspects of fiber cell differentiation; however, the molecular basis of this "rescue" remains undefined. We performed transcriptomic analysis by RNA sequencing of mouse lenses with conditional deletion of Fgfr2, Pten or both Fgfr2 and Pten, which reveal new molecular mechanisms that uncover how FGFR2 and PTEN signaling interact during development. The FGFR2-deficient lens transcriptome demonstrates overall loss of fiber cell identity with deregulated expression of 1448 genes. We find that ~ 60% of deregulated genes return to normal expression levels in lenses lacking both Fgfr2 and Pten. Further, application of customized filtering parameters to these RNA-seq data sets identified 68 high-priority candidate genes. Bioinformatics analyses showed that the cis-binding motif of a high-priority homeodomain transcription factor, NKX6-1, was present in the putative promoters of ~ 78% of these candidates. Finally, biochemical reporter assays demonstrate that NKX6-1 activated the expression of the high-priority candidate Rasgrp1, a RAS-activating protein. Together, these data define a novel regulatory module in which NKX6-1 directly activates Rasgrp1 expression to restore the balance of ERK and AKT activation, thus providing new insights into alternate regulation of FGFR downstream events.
Collapse
Affiliation(s)
| | - Deepti Anand
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Thanh V Hoang
- Department of Biology, Miami University, Oxford, OH, 45056, USA.,Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Blake R Chaffee
- Department of Biology, Miami University, Oxford, OH, 45056, USA
| | - Lin Liu
- Department of Biology, Miami University, Oxford, OH, 45056, USA
| | - Chun Liang
- Department of Biology, Miami University, Oxford, OH, 45056, USA
| | - Salil A Lachke
- Department of Biological Sciences, University of Delaware, Newark, DE, USA.,Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, USA
| | | |
Collapse
|