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Ishimoto Y, Menezes LF, Zhou F, Yoshida T, Komori T, Qiu J, Young MF, Lu H, Potapova S, Outeda P, Watnick T, Germino GG. A novel ARPKD mouse model with near-complete deletion of the Polycystic Kidney and Hepatic Disease 1 (Pkhd1) genomic locus presents with multiple phenotypes but not renal cysts. Kidney Int 2023; 104:611-616. [PMID: 37419448 PMCID: PMC10529617 DOI: 10.1016/j.kint.2023.05.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 05/04/2023] [Accepted: 05/26/2023] [Indexed: 07/09/2023]
Affiliation(s)
- Yu Ishimoto
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Luis F Menezes
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA.
| | - Fang Zhou
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Teruhiko Yoshida
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Taishi Komori
- Molecular Biology of Bones and Teeth Section, Department of Health and Human Services (DHHS), National Institutes of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Jiahe Qiu
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Marian F Young
- Molecular Biology of Bones and Teeth Section, Department of Health and Human Services (DHHS), National Institutes of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Huiyan Lu
- Mouse Transgenic Core Facility, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Svetlana Potapova
- Mouse Transgenic Core Facility, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Patricia Outeda
- Division of Nephrology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Terry Watnick
- Division of Nephrology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Gregory G Germino
- Polycystic Kidney Disease Section, Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), National Institutes of Health (NIH), Bethesda, Maryland, USA.
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Epstein RJ, Lin FPY, Brink RA, Blackburn J. Synonymous alterations of cancer-associated Trp53 CpG mutational hotspots cause fatal developmental jaw malocclusions but no tumors in knock-in mice. PLoS One 2023; 18:e0284327. [PMID: 37053216 PMCID: PMC10101519 DOI: 10.1371/journal.pone.0284327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 03/28/2023] [Indexed: 04/14/2023] Open
Abstract
Intragenic CpG dinucleotides are tightly conserved in evolution yet are also vulnerable to methylation-dependent mutation, raising the question as to why these functionally critical sites have not been deselected by more stable coding sequences. We previously showed in cell lines that altered exonic CpG methylation can modify promoter start sites, and hence protein isoform expression, for the human TP53 tumor suppressor gene. Here we extend this work to the in vivo setting by testing whether synonymous germline modifications of exonic CpG sites affect murine development, fertility, longevity, or cancer incidence. We substituted the DNA-binding exons 5-8 of Trp53, the mouse ortholog of human TP53, with variant-CpG (either CpG-depleted or -enriched) sequences predicted to encode the normal p53 amino acid sequence; a control construct was also created in which all non-CpG sites were synonymously substituted. Homozygous Trp53-null mice were the only genotype to develop tumors. Mice with variant-CpG Trp53 sequences remained tumor-free, but were uniquely prone to dental anomalies causing jaw malocclusion (p < .0001). Since the latter phenotype also characterises murine Rett syndrome due to dysfunction of the trans-repressive MeCP2 methyl-CpG-binding protein, we hypothesise that CpG sites may exert non-coding phenotypic effects via pre-translational cis-interactions of 5-methylcytosine with methyl-binding proteins which regulate mRNA transcript initiation, expression or splicing, although direct effects on mRNA structure or translation are also possible.
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Affiliation(s)
- Richard J Epstein
- University of New South Wales, St Vincent's Hospital Campus, Sydney, Australia
- Garvan Institute of Medical Research, Sydney, Australia
| | - Frank P Y Lin
- University of New South Wales, St Vincent's Hospital Campus, Sydney, Australia
- Centre for Clinical Genomics, The Kinghorn Cancer Centre, Sydney, Australia
| | - Robert A Brink
- University of New South Wales, St Vincent's Hospital Campus, Sydney, Australia
- Garvan Institute of Medical Research, Sydney, Australia
| | - James Blackburn
- University of New South Wales, St Vincent's Hospital Campus, Sydney, Australia
- Garvan Institute of Medical Research, Sydney, Australia
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Lipphardt M, Dihazi H, Müller GA, Goligorsky MS. Fibrogenic Secretome of Sirtuin 1-Deficient Endothelial Cells: Wnt, Notch and Glycocalyx Rheostat. Front Physiol 2018; 9:1325. [PMID: 30298020 PMCID: PMC6160542 DOI: 10.3389/fphys.2018.01325] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/03/2018] [Indexed: 12/31/2022] Open
Abstract
Sirtuins (SIRT) are ubiquitous histone and protein deacetylases and a member of this family, SIRT1, is the best-studied one. Its functions in endothelial cells encompass branching angiogenesis, activation of endothelial nitric oxide synthase, regulation of proapoptotic and proinflammatory pathways, among others. Defective SIRT1 activity has been described in various cardiovascular, renal diseases and in aging-associated conditions. Therefore, understanding of SIRT1-deficient, endothelial dysfunctional phenotype has much to offer clinically. Here, we summarize recent studies by several investigative teams of the characteristics of models of global endothelial SIRT1 deficiency, the causes of facilitative development of fibrosis in these conditions, dissect the protein composition of the aberrant secretome of SIRT1-deficient endothelial cells and present several components of this aberrant secretome that are involved in fibrogenesis via activation of fibroblasts to myofibroblasts. These include ligands of Wnt and Notch pathways, as well as proteolytic fragments of glycocalyx core protein, syndecan-4. The latter finding is crucial for understanding the degradation of glycocalyx that accompanies SIRT1 deficiency. This spectrum of abnormalities associated with SIRT1 deficiency in endothelial cells is essential for understanding the origins and features of endothelial dysfunction in a host of cardiovascular and renal diseases.
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Affiliation(s)
- Mark Lipphardt
- Departments of Medicine, Physiology and Pharmacology, New York Medical College, Valhalla, NY, United States.,Clinic for Nephrology and Rheumatology, Göttingen University Medical Faculty, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Hassan Dihazi
- Clinic for Nephrology and Rheumatology, Göttingen University Medical Faculty, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Gerhard A Müller
- Clinic for Nephrology and Rheumatology, Göttingen University Medical Faculty, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Michael S Goligorsky
- Departments of Medicine, Physiology and Pharmacology, New York Medical College, Valhalla, NY, United States
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McBurney MW, Clark-Knowles KV, Caron AZ, Gray DA. SIRT1 is a Highly Networked Protein That Mediates the Adaptation to Chronic Physiological Stress. Genes Cancer 2013; 4:125-34. [PMID: 24020004 DOI: 10.1177/1947601912474893] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
SIRT1 is a NAD(+)-dependent protein deacetylase that has a very large number of established protein substrates and an equally impressive list of biological functions thought to be regulated by its activity. Perhaps as notable is the remarkable number of points of conflict concerning the role of SIRT1 in biological processes. For example, evidence exists suggesting that SIRT1 is a tumor suppressor, is an oncogene, or has no effect on oncogenesis. Similarly, SIRT1 is variably reported to induce, inhibit, or have no effect on autophagy. We believe that the resolution of many conflicting results is possible by considering recent reports indicating that SIRT1 is an important hub interacting with a complex network of proteins that collectively regulate a wide variety of biological processes including cancer and autophagy. A number of the interacting proteins are themselves hubs that, like SIRT1, utilize intrinsically disordered regions for their promiscuous interactions. Many studies investigating SIRT1 function have been carried out on cell lines carrying undetermined numbers of alterations to the proteins comprising the SIRT1 network or on inbred mouse strains carrying fixed mutations affecting some of these proteins. Thus, the effects of modulating SIRT1 amount and/or activity are importantly determined by the genetic background of the cell (or the inbred strain of mice), and the effects attributed to SIRT1 are synthetic with the background of mutations and epigenetic differences between cells and organisms. Work on mice carrying alterations to the Sirt1 gene suggests that the network in which SIRT1 functions plays an important role in mediating physiological adaptation to various sources of chronic stress such as calorie restriction and calorie overload. Whether the catalytic activity of SIRT1 and the nuclear concentration of the co-factor, NAD(+), are responsible for modulating this activity remains to be determined. However, the effect of modulating SIRT1 activity must be interpreted in the context of the cell or tissue under investigation. Indeed, for SIRT1, we argue that context is everything.
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Affiliation(s)
- Michael W McBurney
- Program in Cancer Therapeutics, Ottawa Hospital Research Institute ; Department of Medicine, University of Ottawa, Ottawa, ON, Canada
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