1
|
Nasrallah R, Fast EM, Solaimani P, Knezevic K, Eliades A, Patel R, Thambyrajah R, Unnikrishnan A, Thoms J, Beck D, Vink CS, Smith A, Wong J, Shepherd M, Kent D, Roychoudhuri R, Paul F, Klippert J, Hammes A, Willnow T, Göttgens B, Dzierzak E, Zon LI, Lacaud G, Kouskoff V, Pimanda JE. Identification of novel regulators of developmental hematopoiesis using Endoglin regulatory elements as molecular probes. Blood 2016; 128:1928-1939. [PMID: 27554085 PMCID: PMC5064716 DOI: 10.1182/blood-2016-02-697870] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 08/15/2016] [Indexed: 12/13/2022] Open
Abstract
Enhancers are the primary determinants of cell identity, and specific promoter/enhancer combinations of Endoglin (ENG) have been shown to target blood and endothelium in the embryo. Here, we generated a series of embryonic stem cell lines, each targeted with reporter constructs driven by specific promoter/enhancer combinations of ENG, to evaluate their discriminative potential and value as molecular probes of the corresponding transcriptome. The Eng promoter (P) in combination with the -8/+7/+9-kb enhancers, targeted cells in FLK1 mesoderm that were enriched for blast colony forming potential, whereas the P/-8-kb enhancer targeted TIE2+/c-KIT+/CD41- endothelial cells that were enriched for hematopoietic potential. These fractions were isolated using reporter expression and their transcriptomes profiled by RNA-seq. There was high concordance between our signatures and those from embryos with defects at corresponding stages of hematopoiesis. Of the 6 genes that were upregulated in both hemogenic mesoderm and hemogenic endothelial fractions targeted by the reporters, LRP2, a multiligand receptor, was the only gene that had not previously been associated with hematopoiesis. We show that LRP2 is indeed involved in definitive hematopoiesis and by doing so validate the use of reporter gene-coupled enhancers as probes to gain insights into transcriptional changes that facilitate cell fate transitions.
Collapse
Affiliation(s)
- Rabab Nasrallah
- Lowy Cancer Research Centre and the Prince of Wales Clinical School, University of New South Wales Australia, Sydney, Australia
| | - Eva M Fast
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA; Howard Hughes Medical Institute, Stem Cell Program and Division of Pediatric Hematology/Oncology, Boston Children's Hospital, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA
| | - Parham Solaimani
- Erasmus Medical Center Stem Cell Institute, Department of Cell Biology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Kathy Knezevic
- Lowy Cancer Research Centre and the Prince of Wales Clinical School, University of New South Wales Australia, Sydney, Australia
| | - Alexia Eliades
- Cancer Research United Kingdom Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Rahima Patel
- Cancer Research United Kingdom Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Roshana Thambyrajah
- Cancer Research United Kingdom Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Ashwin Unnikrishnan
- Lowy Cancer Research Centre and the Prince of Wales Clinical School, University of New South Wales Australia, Sydney, Australia
| | - Julie Thoms
- Lowy Cancer Research Centre and the Prince of Wales Clinical School, University of New South Wales Australia, Sydney, Australia
| | - Dominik Beck
- Lowy Cancer Research Centre and the Prince of Wales Clinical School, University of New South Wales Australia, Sydney, Australia
| | - Chris S Vink
- Erasmus Medical Center Stem Cell Institute, Department of Cell Biology, Erasmus University Medical Center, Rotterdam, The Netherlands; Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Aileen Smith
- Department of Haematology, Wellcome Trust and Medical Research Council Cambridge Stem Cell Institute and Cambridge Institute for Medical Research, Cambridge University, Cambridge, United Kingdom
| | - Jason Wong
- Lowy Cancer Research Centre and the Prince of Wales Clinical School, University of New South Wales Australia, Sydney, Australia
| | - Mairi Shepherd
- Department of Haematology, Wellcome Trust and Medical Research Council Cambridge Stem Cell Institute and Cambridge Institute for Medical Research, Cambridge University, Cambridge, United Kingdom
| | - David Kent
- Department of Haematology, Wellcome Trust and Medical Research Council Cambridge Stem Cell Institute and Cambridge Institute for Medical Research, Cambridge University, Cambridge, United Kingdom
| | - Rahul Roychoudhuri
- The Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom
| | - Fabian Paul
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany; and
| | - Julia Klippert
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany; and
| | - Annette Hammes
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany; and
| | - Thomas Willnow
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany; and
| | - Bertie Göttgens
- Department of Haematology, Wellcome Trust and Medical Research Council Cambridge Stem Cell Institute and Cambridge Institute for Medical Research, Cambridge University, Cambridge, United Kingdom
| | - Elaine Dzierzak
- Erasmus Medical Center Stem Cell Institute, Department of Cell Biology, Erasmus University Medical Center, Rotterdam, The Netherlands; Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Leonard I Zon
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA; Howard Hughes Medical Institute, Stem Cell Program and Division of Pediatric Hematology/Oncology, Boston Children's Hospital, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA
| | - George Lacaud
- Cancer Research United Kingdom Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Valerie Kouskoff
- Cancer Research United Kingdom Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - John E Pimanda
- Lowy Cancer Research Centre and the Prince of Wales Clinical School, University of New South Wales Australia, Sydney, Australia; Department of Haematology, The Prince of Wales Hospital, Sydney, Australia
| |
Collapse
|
2
|
Markmann S, Thelen M, Cornils K, Schweizer M, Brocke-Ahmadinejad N, Willnow T, Heeren J, Gieselmann V, Braulke T, Kollmann K. Lrp1/LDL Receptor Play Critical Roles in Mannose 6-Phosphate-Independent Lysosomal Enzyme Targeting. Traffic 2015; 16:743-59. [DOI: 10.1111/tra.12284] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/12/2015] [Accepted: 03/13/2015] [Indexed: 01/01/2023]
Affiliation(s)
- Sandra Markmann
- Department for Biochemistry, Children's Hospital; University Medical Center Hamburg-Eppendorf; D-20246 Hamburg Germany
| | - Melanie Thelen
- Institute of Biochemistry and Molecular Biology; University of Bonn; Nussallee 11 D-53115 Bonn Germany
| | - Kerstin Cornils
- Research Department Cell and Gene Therapy, Clinic for Stem Cell Transplantation; University Medical Center Hamburg-Eppendorf; D-20246 Hamburg Germany
| | - Michaela Schweizer
- Center for Molecular Neurobiology Hamburg, ZMNH; University Medical Center Hamburg-Eppendorf; 20246 Hamburg Germany
| | - Nahal Brocke-Ahmadinejad
- Institute of Biochemistry and Molecular Biology; University of Bonn; Nussallee 11 D-53115 Bonn Germany
| | - Thomas Willnow
- Max Delbrück Center for Molecular Medicine; 13125 Berlin-Buch Germany
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology; University Medical Center Hamburg-Eppendorf; D-20246 Hamburg Germany
| | - Volkmar Gieselmann
- Institute of Biochemistry and Molecular Biology; University of Bonn; Nussallee 11 D-53115 Bonn Germany
| | - Thomas Braulke
- Department for Biochemistry, Children's Hospital; University Medical Center Hamburg-Eppendorf; D-20246 Hamburg Germany
| | - Katrin Kollmann
- Department for Biochemistry, Children's Hospital; University Medical Center Hamburg-Eppendorf; D-20246 Hamburg Germany
| |
Collapse
|
3
|
Carlo AS, Gustafsen C, Mastrobuoni G, Nielsen M, Kempa S, Petersen CM, Willnow T. The pro-neurotrophin receptor sortilin is a major neuronal APOE receptor for catabolism of amyloid-β peptide in the brain. Mol Neurodegener 2013. [PMCID: PMC3847090 DOI: 10.1186/1750-1326-8-s1-p10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
4
|
Mutig K, Borschewski A, Willnow T, Dathe C, Paliege A, Ferreri N, Bachmann S. Interactions between sorting protein‐related receptor and calcineurin to activate renal Na‐K‐2Cl cotransporter. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.912.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kerim Mutig
- Institut für Vegetative AnatomieCharité ‐ Universitätsmedizin BerlinBerlinGermany
| | - Aljona Borschewski
- Institut für Vegetative AnatomieCharité ‐ Universitätsmedizin BerlinBerlinGermany
| | - Thomas Willnow
- Max‐Delbrück‐ Centrum für Molekulare MedizinBerlinGermany
| | - Christin Dathe
- Institut für Vegetative AnatomieCharité ‐ Universitätsmedizin BerlinBerlinGermany
| | - Alexander Paliege
- Institut für Vegetative AnatomieCharité ‐ Universitätsmedizin BerlinBerlinGermany
| | | | - Sebastian Bachmann
- Institut für Vegetative AnatomieCharité ‐ Universitätsmedizin BerlinBerlinGermany
| |
Collapse
|
5
|
Schmidt V, Baum K, Lao A, Rateitschak K, Teichmann A, Wiesner B, Wolf J, Wolkenhauer O, Willnow T. P2‐096: Quantitative modeling of amyloidogenic processing and its influence by SORLA/SORL1 in Alzheimer's disease. Alzheimers Dement 2012. [DOI: 10.1016/j.jalz.2012.05.800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
6
|
Borschewski A, Willnow T, Dathe C, Paliege A, Ferreri N, Bachmann S, Mutig K. Sorting protein‐related receptor SorLA is involved in regulation of renal Na+‐K+‐2Cl‐cotransporter through interaction with an isoform of calcineurin phosphatase. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1152.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Thomas Willnow
- Max-Delbrück-Centrum für Molekulare MedizinBerlinGermany
| | | | | | | | | | - Kerim Mutig
- Charité Universitätsmedizin BerlinBerlinGermany
| |
Collapse
|
7
|
Carlo A, Willnow T, Petersen CM, Gustafsen C. P1‐004: Pro‐neurotrophin receptor sortilin in neurodegenerative processes and Alzheimer's disease. Alzheimers Dement 2011. [DOI: 10.1016/j.jalz.2011.05.284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
8
|
Burgert T, Caglayan S, Schmidt V, Willnow T. P3‐198: Relevance of the interaction between SORLA and cytosolic adaptor proteins for amyloidogenic processing. Alzheimers Dement 2011. [DOI: 10.1016/j.jalz.2011.05.1639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Tilman Burgert
- Max‐Delbrueck‐Center for Molecular MedicineBerlinGermany
| | - Safak Caglayan
- Max‐Delbrueck‐Center for Molecular MedicineBerlinGermany
| | | | - Thomas Willnow
- Max‐Delbrueck‐Center for Molecular MedicineBerlinGermany
| |
Collapse
|
9
|
Caglayan S, Schmidt V, Carlo A, Bauerfeind A, Huebner N, Willnow T. P1‐216: Identification of Alzheimer's Disease Haplotype that Predicts Efficiency of SORL1/SORLA Expression in the Brain. Alzheimers Dement 2011. [DOI: 10.1016/j.jalz.2011.05.495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Safak Caglayan
- Max‐Delbrueck‐Center for Molecular MedicineBerlinGermany
| | | | | | | | | | - Thomas Willnow
- Max‐Delbrueck‐Center for Molecular MedicineBerlinGermany
| |
Collapse
|
10
|
Schmidt V, Baum K, Lao A, Rateitschak K, Petersen CM, Wolf J, Wolkenhauer O, Willnow T. P2‐313: Quantitative modeling of amyloidogenic processing and its influence by SORLA/SORL1 in AlzheimerÂś disease. Alzheimers Dement 2011. [DOI: 10.1016/j.jalz.2011.05.1191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
11
|
Willnow T. F2‐01‐02: Sorting Receptor Sorla Regulates Multiple Steps in Neuronal App Transport and Processing. Alzheimers Dement 2011. [DOI: 10.1016/j.jalz.2011.05.816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Thomas Willnow
- Max‐Delbrueck‐Center for Molecular MedicineBerlinGermany
| |
Collapse
|
12
|
Sorensen MV, Praetorius HA, Nykjaer A, Willnow T, Leipziger J. Impaired aldosterone responsiveness in corticosteroid binding globulin deficient mice. Acta Physiol (Oxf) 2011; 201:169-77. [PMID: 20969731 DOI: 10.1111/j.1748-1716.2010.02208.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM Corticosteroid binding globulin (CBG) is the high affinity plasma carrier protein for cortisol. It keeps the steroids inactive, prevents them from degradation and defines the amount of free hormone acting on target tissues. Previous findings have shown insufficient responsiveness of corticosterone in peripheral tissues in CBG⁻(/)⁻ mice despite elevated free plasma corticosterone. In the large intestine, glucocorticoids synergistically enhance the pro-absorptive effects of aldosterone. We therefore hypothesized that CBG⁻(/)⁻ mice have reduced responsiveness to aldosterone. METHODS We used CBG⁻(/)⁻ and CBG(+/+) mice to investigate distal colonic electrogenic Na(+) absorption. An Ussing chamber was used to quantify amiloride-sensitive Na(+) transport in distal colonic mucosa (ΔI(sc) (amil)) as a measure of the physiological effect of aldosterone. RESULTS No differences were observed in ΔI(sc) (amil) or aldosterone levels in animals on control diet. When Na(+) restricted, CBG(+/+) mice responded with a marked up-regulation of ΔI(sc) (amil) (25-fold). In CBG⁻(/)⁻ mice this up-regulation was greatly attenuated as seen in a markedly reduced amiloride-sensitive short circuit current (reduced by ∼50%), a reduced ability to lower faecal Na(+) excretion and a significantly attenuated up-regulation of the ENaC channel γ-subunit. Diet-induced increases of total plasma aldosterone were similar in both genotypes, but CBG⁻(/)⁻ mice had an increased free plasma aldosterone fraction. SUMMARY This study defines the functional hyporesponsiveness and aldosterone resistance in distal colon of CBG⁻(/)⁻ mice. This resistance occurs despite sufficient free corticosterone plasma level. Thus, steroid actions require an intrinsic but unknown function of CBG, which allows the sufficient supply of the hormone/s to the target tissue.
Collapse
Affiliation(s)
- M V Sorensen
- Department of Physiology and Biophysics, The Water and Salt Research Center, Aarhus University, Denmark
| | | | | | | | | |
Collapse
|
13
|
Theilig F, Kriz W, Jerichow T, Schrade P, Hähnel B, Willnow T, Le Hir M, Bachmann S. Abrogation of Protein Uptake through Megalin-Deficient Proximal Tubules Does Not Safeguard against Tubulointerstitial Injury. J Am Soc Nephrol 2007; 18:1824-34. [PMID: 17460141 DOI: 10.1681/asn.2006111266] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Sustained proteinuria and tubulointerstitial damage have been closely linked with progressive renal failure. Upon excess protein endocytosis, tubular epithelial cells are thought to produce mediators that promote inflammation, tubular degeneration, and fibrosis. This concept was tested in a transgenic mouse model with megalin deficiency. Application of an anti-glomerular basement membrane serum to transgenic megalin-deficient mice [Cre(+)/GN] and megalin-positive littermates [Cre(-)/GN] produced the typical glomerulonephritis (GN) with heavy proteinuria in both groups. Tubulointerstitial damages correlated closely with glomerular damages in pooled Cre(+)/GN and Cre(-)/GN mice. Owing to a mosaic pattern of megalin expression in the mutant mice, Cre(+)/GN kidneys permitted side-by-side analysis of megalin-deficient and megalin-positive tubules in the same kidney. Protein endocytosis was found only in megalin-positive cells. TGF-beta, intercellular adhesion molecule, vascular cellular adhesion molecule, endothelin-1, and cell proliferation were high in megalin-positive cells, whereas apoptosis, heat-shock protein 25, and osteopontin were enhanced in megalin-deficient cells. No fibrotic changes were associated with either phenotype. Tubular degeneration with interstitial inflammation was found only in nephrons with extensive crescentic lesions at the glomerulotubular junction. In sum, enhanced protein endocytosis indeed led to an upregulation of profibrotic mediators in a megalin-dependent way; however, there was no evidence that endocytosis played a pathogenetic role in the development of the tubulointerstitial disease.
Collapse
Affiliation(s)
- Franziska Theilig
- Institut für Vegetative Anatomie, Charité Universitätsmedizin Berlin, Philippstrasse 12, 10115 Berlin
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Andersen OM, Schmidt V, Spoelgen R, Gliemann J, Behlke J, Galatis D, McKinstry W, Parker M, Masters C, Hyman B, Cappai R, Willnow T. P3–423: Molecular dissection of the interaction between APP and its neuronal trafficking receptor SorLA/LR11. Alzheimers Dement 2006. [DOI: 10.1016/j.jalz.2006.05.1694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
| | | | | | | | - Joachim Behlke
- Max-Delbrueck-Center for Molecular MedicineBerlinGermany
| | - Denise Galatis
- The Mental Health Research Institute of VictoriaParkvilleAustralia
| | | | - Michael Parker
- St. Vincent's Institute of Medical ResearchVictoriaAustralia
| | - Colin Masters
- The Mental Health Research Institute of VictoriaParkvilleAustralia
| | | | - Roberto Cappai
- The Mental Health Resarch Institute of VictoriaParkvilleAustralia
| | - Thomas Willnow
- Max-Delbrueck-Center for Molecular MedicineBerlinGermany
| |
Collapse
|
15
|
Dodson SE, Carter SC, Willnow T, Levey AI, Lah JJ. P1–115: Characterization of PS1/APP mice deficient for the ApoE receptor sorLA/LR11. Alzheimers Dement 2006. [DOI: 10.1016/j.jalz.2006.05.491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
16
|
Donath S, Li P, Willenbockel C, Al-Saadi N, Gross V, Willnow T, Bader M, Martin U, Bauersachs J, Wollert KC, Dietz R, von Harsdorf R. Apoptosis repressor with caspase recruitment domain is required for cardioprotection in response to biomechanical and ischemic stress. Circulation 2006; 113:1203-12. [PMID: 16505176 DOI: 10.1161/circulationaha.105.576785] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Ischemic heart disease and heart failure are associated with an increased loss of cardiomyocytes due to apoptosis. Whether cardiomyocyte apoptosis plays a causal role in the pathogenesis of heart failure remains enigmatic. The apoptosis repressor with caspase recruitment domain (ARC) is a recently discovered antiapoptotic factor with a highly specific expression pattern in striated muscle and neurons. ARC is a master regulator of cardiac death signaling because it is the only known factor that specifically inhibits both the intrinsic and extrinsic apoptotic death pathway. In this study we attempted to elucidate the physiological role of ARC and to understand pathophysiological consequences resulting from its deletion. METHODS AND RESULTS We generated ARC-deficient mice, which developed normally to adulthood and had no abnormality in cardiac morphology and function under resting conditions. On biomechanical stress induced by aortic banding, ARC-deficient mice developed accelerated cardiomyopathy compared with littermate controls, which was characterized by reduced contractile function, cardiac enlargement, and myocardial fibrosis. Likewise, ischemia/reperfusion injury of ARC-deficient mice resulted in markedly increased myocardial infarct sizes. Although in both instances a significant increase in apoptotic cardiomyocytes could be observed in ARC-deficient mice, neither in vitro nor in vivo studies revealed any effect of ARC on classic hypertrophic cardiomyocyte growth responses. The pathophysiological relevance of downregulated ARC levels was underscored by specimens from failing human hearts showing markedly reduced ARC protein levels. CONCLUSIONS Our study identifies a tissue-specific antiapoptotic factor that is downregulated in human failing myocardium and that is required for cardioprotection in pressure overload and ischemia.
Collapse
Affiliation(s)
- Stefan Donath
- Department of Cardiology, Campus Virchow Clinic, Charité, Humboldt University, HELIOS GmbH, Berlin, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Cichon G, Willnow T, Herwig S, Uckert W, Löser P, Schmidt HH, Benhidjeb T, Schlag PM, Schnieders F, Niedzielska D, Heeren J. Non-physiological overexpression of thelow density lipoprotein receptor(LDLr) gene in the liver induces pathological intracellular lipid and cholesterol storage. J Gene Med 2004; 6:166-75. [PMID: 14978770 DOI: 10.1002/jgm.473] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Gene therapy of familial hypercholesterolemia (FH) requires successful transfer and lifelong expression of a functional low density lipoprotein receptor (LDLr) gene in the liver. Most of the vector systems currently employed for gene therapy use promoter elements which do not modulate transgene expression in a physiological manner. METHODS To study the in vivo effects of constitutive LDLr gene expression in the absence of interfering immunological reactions we established a new mouse model which combines homozygous LDLr deficiency and severe combined immune deficiency (SCID). RESULTS Adenovirus-mediated transfer and expression of the LDLr gene under the control of a commonly used virus-derived promoter (minimal CMV promoter) leads to prolonged reduction of serum cholesterol levels in LDLr-deficient SCID mice. During the first 10 days after gene therapy serum cholesterol drops to about 10% of pretherapeutic values. Serum cholesterol persists on this level for 2 weeks and then slowly starts to rise again. Four months after vector application serum levels have reached about 40% of pretherapeutic values. However, as early as 5 days after gene transfer, the histological analysis of liver sections revealed the formation of crystalline lipid/cholesterol deposits in the cytosol of hepatocytes. During the following 8 weeks the amount of crystals increased in size and density. The intracellular storage of lipid and cholesterol reduced cell viability and induced an accelerated loss of therapeutic DNA from mice livers as was shown in a comparative expression study employing a transgene with a different metabolic function (human alpha 1-antitrypsin). CONCLUSIONS The non-physiological constitutive overexpression of an LDL receptor gene induces an imbalance between the speed of LDL uptake and metabolism which leads to pathological accumulation of lipids and cholesterol in hepatocytes. To protect cells from negative effects of LDLr overexpression, future vector design should consider the use of physiologically controlled expression elements.
Collapse
Affiliation(s)
- Guenter Cichon
- Department of Molecular Cell Biology, Humboldt-University Berlin at the Max Delbrueck Center for Molecular Medicine, Robert-Roessle-Str. 10, 13125 Berlin, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Knecht M, Pagel I, Langenickel T, Philipp S, Scheuermann-Freestone M, Willnow T, Bruemmer D, Graf K, Dietz R, Willenbrock R. Increased expression of renal neutral endopeptidase in severe heart failure. Life Sci 2002; 71:2701-12. [PMID: 12383878 DOI: 10.1016/s0024-3205(02)01990-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The enzyme neutral endopeptidase (NEP; EC 3.4.24.11) cleaves several vasoactive peptides such as the atrial natriuretic peptide (ANP). ANP is a hormone of cardiac origin with diuretic and natriuretic actions. Despite elevated circulating levels of ANP, congestive heart failure (CHF) is characterized by progressive sodium and water retention. In order to elucidate the loss of natriuretic and diuretic properties of ANP in CHF we analyzed activity, protein concentrations, mRNA and immunostaining of NEP in kidneys of different models of severe CHF in the rat.CHF was induced by either aortocaval shunt, aortic banding or myocardial infarction in the rat. All models were defined by increased left ventricular end-diastolic pressure and decreased contractility. The diminished effectiveness of ANP was reflected by reduced cGMP/ANP ratio in animals with shunt or infarction. Renal NEP activity was increased in rats with aortocaval shunt (203 +/- 7%, p < 0.001), aortic banding (184 +/- 11%, p < 0.001) and infarction (149 +/- 10%, p < 0.005). Western blot analysis revealed a significant increase in renal NEP protein content in two models of CHF (shunt: 214 +/- 57%, p < 0.05; infarction: 310 +/- 53 %, p < 0.01). The elevated protein expression was paralleled by a threefold increase in renal NEP-mRNA level in the infarction model. The increased renal NEP protein expression and activity may lead to enhanced degradation of ANP and may contribute to the decreased renal response to ANP in heart failure. Thus, the capacity to counteract sodium and water retention, would be diminished. The increased renal NEP activity may therefore be a hitherto unknown factor in the progression of CHF.
Collapse
Affiliation(s)
- Mathias Knecht
- Medical Science Department, Boehringer Ingelheim Pharma KG, 55216 Ingelheim am Rhein, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Niemeier A, Willnow T, Dieplinger H, Jacobsen C, Meyer N, Hilpert J, Beisiegel U. Identification of megalin/gp330 as a receptor for lipoprotein(a) in vitro. Arterioscler Thromb Vasc Biol 1999; 19:552-61. [PMID: 10073957 DOI: 10.1161/01.atv.19.3.552] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Lipoprotein(a) [Lp(a)] is an atherogenic lipoprotein of unknown physiological function. The mechanism of Lp(a) atherogenicity as well as its catabolic pathways are only incompletely understood at present. In this report, we show that the low density lipoprotein receptor (LDLR) gene family member megalin/glycoprotein (gp) 330 is capable of binding and mediating the cellular uptake and degradation of Lp(a) in vitro. A mouse embryonic yolk sac cell line with native expression of megalin/gp330 but genetically deficient in LDLR-related protein (LRP) and a control cell line carrying a double knockout for both LRP and megalin/gp330 were compared with regard to their ability to bind, internalize, and degrade dioctadecyltetramethylindocarbocyanine perchlorate (DiI)-fluorescence-labeled Lp(a) as well as equimolar amounts of 125I-labeled Lp(a) and LDL. Uptake and degradation of radiolabeled Lp(a) by the megalin/gp330-expressing cells were, on average, 2-fold higher than that of control cells. This difference could be completely abolished by addition of the receptor-associated protein, an inhibitor of ligand binding to megalin/gp330. Mutual suppression of the uptake of 125I-Lp(a) and of 125I-LDL by both unlabeled Lp(a) and LDL suggested that Lp(a) uptake is mediated at least partially by apolipoprotein B100. Binding and uptake of DiI-Lp(a) resulted in strong signals on megalin/gp330-expressing cells versus background only on control cells. In addition, we show that purified megalin/gp330, immobilized on a sensor chip, directly binds Lp(a) in a Ca2+-dependent manner with an affinity similar to that for LDL. We conclude that megalin/gp330 binds Lp(a) in vitro and is capable of mediating its cellular uptake and degradation.
Collapse
Affiliation(s)
- A Niemeier
- Medical Clinic, University Hospital Eppendorf, Hamburg, Germany
| | | | | | | | | | | | | |
Collapse
|
20
|
Reblin T, Niemeier A, Meyer N, Willnow T, Dieplinger H, Beisiegel U, Greten H. 2.P.149 Uptake of lipoprotein(a) by mouse embryonic fibroblasts via the LDL-receptor and/or the LDL receptor-related protein. Atherosclerosis 1997. [DOI: 10.1016/s0021-9150(97)88783-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
21
|
Orth K, Willnow T, Herz J, Gething MJ, Sambrook J. Low density lipoprotein receptor-related protein is necessary for the internalization of both tissue-type plasminogen activator-inhibitor complexes and free tissue-type plasminogen activator. J Biol Chem 1994; 269:21117-22. [PMID: 8063731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Tissue-type plasminogen activator (t-PA) is used as a thrombolytic agent in treatment of myocardial infarction. However, large doses of this agent must be administered in treatment to maintain a thrombolytic state because t-PA is cleared rapidly from circulation. We designed specific ligands to distinguish between two major mechanisms by which t-PA is taken into cells and degraded. One of these mechanisms involves internalization of complexes between t-PA and its cognate inhibitor plasminogen activator inhibitor type-1 (PAI-1); the other mechanism is independent of PAI-1. Using specific inhibitors for low density lipoprotein receptor-related protein/alpha 2-macroglobulin receptor (LRP), we show that the degradation by hepatocytes of both free t-PA and t-PA.PAI-1 complexes involve the receptor LRP. We demonstrate that fibroblasts degrade both free t-PA (PAI-1-independent) and t-PA complexed with its specific inhibitor PAI-1 (PAI-1-dependent), whereas genetically altered fibroblasts that do not express LRP neither internalize nor degrade these ligands. We also show that a PAI-1-independent, t-PA ligand can inhibit the degradation of both free t-PA and t-PA.PAI-1 complexes. We propose LRP is the receptor for both PAI-1-independent and PAI-1-dependent t-PA ligands.
Collapse
Affiliation(s)
- K Orth
- Department of Biochemistry, University of Texas Southwestern Medical School, Dallas 75235
| | | | | | | | | |
Collapse
|
22
|
Orth K, Willnow T, Herz J, Gething M, Sambrook J. Low density lipoprotein receptor-related protein is necessary for the internalization of both tissue-type plasminogen activator-inhibitor complexes and free tissue-type plasminogen activator. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)31937-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
23
|
Abstract
Simian virus 40 (SV40)-containing DNA was rescued after the fusion of SV40-transformed VLM cells with permissive COS1 monkey cells and cloned, and prototype plasmid clones were characterized. A 2-kilobase mouse DNA fragment fused with the rescued SV40 DNA, and derived from mouse DNA flanking the single insert of SV40 DNA in VLM cells, was sequenced. Insertion of the intact rescued mouse sequence, or two nonoverlapping fragments of it, into wild-type SV40 plasmid DNA suppressed replication of the plasmid in TC7 monkey cells, although the plasmids expressed replication-competent T antigen. Rat cells were transformed with linearized wild-type SV40 plasmid DNA with or without fragments of the mouse DNA in cis. Although all of the rat cell lines expressed approximately equal amounts of T antigen and p53, transformants carrying SV40 DNA linked to either of the same two replication suppressor fragments produced significantly less free SV40 DNA after fusion with permissive cells than those transformed by SV40 DNA without a cellular insert or with a cellular insert lacking suppressor activity. The results suggest that two independent segments of cellular DNA act in cis to suppress SV40 replication in vivo, either as a plasmid or integrated in chromosomal DNA.
Collapse
Affiliation(s)
- M Hartl
- Institute for Biochemistry, Munich, Federal Republic of Germany
| | | | | |
Collapse
|