uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Zebrafish larvae as a model system for systematic characterization of drugs and genes in dyslipidemia and atherosclerosis
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medicinsk genetik och genomik.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medicinsk genetik och genomik.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medicinsk genetik och genomik.
Show others and affiliations
(English)In: Article in journal (Refereed) Submitted
Abstract [en]

Background: Hundreds of loci have been robustly associated with circulating lipids, atherosclerosis and coronary artery disease; but for most loci the causal genes and mechanisms remain uncharacterized.

Methods: We developed a semi-automated experimental pipeline for systematic, quantitative, large-scale characterization of mechanisms, drugs and genes associated with dyslipidemia and atherosclerosis in a zebrafish model system. We validated our pipeline using a dietary (n>2000), drug treatment (n>1000), and genetic intervention (n=384).

Results: Our results show that five days of overfeeding and cholesterol supplementation had independent pro-atherogenic effects, which could be diminished by concomitant treatment with atorvastatin and ezetimibe. CRISPR-Cas9-induced mutations in orthologues of proof-of-concept genes resulted in higher LDL cholesterol levels (apoea), and more early stage atherosclerosis (apobb.1).

Conclusions: In summary, our pipeline facilitates systematic, in vivo characterization of drugs and candidate genes to increase our understanding of disease etiology, and can likely help identify novel targets for therapeutic intervention.

National Category
Medical Genetics
Identifiers
URN: urn:nbn:se:uu:diva-378939OAI: oai:DiVA.org:uu-378939DiVA, id: diva2:1295141
Available from: 2019-03-11 Created: 2019-03-11 Last updated: 2019-11-24
In thesis
1. Translating Cardiac and Cardiometabolic GWAS Using Zebrafish
Open this publication in new window or tab >>Translating Cardiac and Cardiometabolic GWAS Using Zebrafish
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Genome-wide association studies (GWAS) have identified thousands of loci associated with cardiac and cardiometabolic traits. However, the trait-associated variants usually do not clearly point to causal gene(s), mechanism(s) or tissue(s). Model systems that allow for a comprehensive and quick candidate gene screening are necessary, ideally in vivo. The overall objective of my thesis is to establish large-scale, imaged-based screens in zebrafish embryos and larvae to examine candidate genes for their effects on heart rate and rhythm, as well as on early-onset atherosclerosis and dyslipidemia.

In Study 1, I prioritized 18 candidate genes in eight loci identified in a meta-analysis of GWAS for heart rate variability. Some of these genes were already known to be involved in cardiac pacemaking, whereas others require functional characterization.

In Study 2, I established an experimental pipeline to examine genetic effects on cardiac rate and rhythm and used it to characterize orthologues of six human candidate genes for heart rate and rhythm. I confirmed known effects of rgs6 and hcn4, and established a role for KIAA1755 in HRV.

In Study 3, I contributed to large-scale experiments to establish the zebrafish as a model system for early-onset atherosclerosis and dyslipidemia. Overfeeding and cholesterol-supplementation of the diet were shown to propel independent pro-atherogenic effects. Atherosclerotic burden was alleviated using commonly prescribed drugs in humans. Lastly, the effects of proof-of-concept genes known to be involved in lipid metabolism were examined and showed higher LDLc (apoea) and early-onset atherosclerosis (apobb1).

In Study 4, I characterized genes in GWAS-identified loci for triglyceride levels for a role in lipid metabolism and early-stage atherosclerosis. I identified three previously unanticipated genes that influence triglyceride levels in zebrafish larvae. Several additional genes influence other cardiometabolic risk factors. Interestingly, two genes showed trends towards lower triglycerides levels (dock7 and lpar2a), with directionally opposite effects on vascular inflammation. This emphasizes that candidate genes need to be examined comprehensively to guide further mechanistic studies.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2019. p. 56
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 1547
Keywords
GWAS, Zebrafish
National Category
Medical Genetics
Research subject
Medical Genetics
Identifiers
urn:nbn:se:uu:diva-378941 (URN)978-91-513-0590-5 (ISBN)
Public defence
2019-04-26, Humanistiska Teatern, Engelska Parken, Thunbergsv. 3H, Uppsala, 09:00 (English)
Opponent
Supervisors
Available from: 2019-04-02 Created: 2019-03-11 Last updated: 2019-05-07
2. Zebrafish models for large-scale genetic screens in dyslipidemia and atherosclerosis: Validation and application
Open this publication in new window or tab >>Zebrafish models for large-scale genetic screens in dyslipidemia and atherosclerosis: Validation and application
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Hundreds of loci have been robustly associated with circulating lipids, atherosclerosis and coronary artery disease; but for most loci the causal genes and mechanisms remain uncharacterized. The overall aim of my thesis is to develop and validate novel in vivo model systems that are suitable for high-throughput, image-based genetic screens in coronary artery disease and related traits, and use these model systems to systematically characterize positional candidate genes.

In Study I, I developed an experimental pipeline to validate the suitability of zebrafish larvae as a model system for systematic, large-scale characterization of drugs and genes associated with dyslipidemia and atherosclerosis. Using this pipeline, I showed that five days of overfeeding and cholesterol supplementation have independent pro-atherogenic effects in zebrafish larvae, which could be diminished by concomitant treatment with atorvastatin and ezetimibe. CRISPR-Cas9-induced mutations in orthologues of proof-of-concept genes resulted in higher LDL cholesterol levels (apoea), and more early stage atherosclerosis (apobb.1). Finally, the pipeline helped me to identify putative causal genes for circulating lipids and early-stage atherosclerosis (LPAR2 and GATAD2A).

In Study II, I characterized cardiometabolic traits in apoc2 mutant zebrafish larvae and found that, similar to humans, larvae with two non-functional apoc2 alleles have higher whole-body levels of triglycerides and total cholesterol, and more vascular lipid deposition than larvae without mutations in apoc2. Interestingly, apoc2 mutant larvae also had lower glucose levels after adjusting for triglyceride levels, suggesting that therapeutic stimulation of apoc2 to prevent hypertriglyceridemia may result in hyperglycemia. Still, zebrafish larvae with mutations in apoc2 can be a useful model to identify and characterize additional causal genes for triglyceride metabolism.

In Study III, I examined the effects of mutations in pcsk9 on atherosclerosis and diabetes-related traits in nearly 5,000 zebrafish larvae. Similar to the loss-of-function mutations in PCSK9 in humans, larvae with mutations in pcsk9 had lower LDLc levels and were protected from early-stage atherosclerosis. Interestingly, mutations in pcsk9 also resulted in fewer pancreatic β-cells in 10 days old larvae, which suggests the higher risk of diabetes in humans with mutations in PCSK9 may result from a direct effect on the beta cell.

Based on these large-scale proof-of-concept studies, my thesis confirms that zebrafish larvae can be used for large-scale, systematic genetic screens in dyslipidemia and early-stage atherosclerosis.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2019. p. 46
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 1619
Keywords
zebrafish, dyslipidemia, atherosclerosis, genetic screens, high-cholesterol diet, APOE, APOB, LDLR, APOC2, PCSK9, LPAR2, GATAD2A
National Category
Medical Genetics
Research subject
Medical Genetics
Identifiers
urn:nbn:se:uu:diva-397715 (URN)978-91-513-0822-7 (ISBN)
Public defence
2020-01-16, Humanistiska teatern, Engelska Parken, Thunbergsv. 3H, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2019-12-20 Created: 2019-11-24 Last updated: 2020-01-14

Open Access in DiVA

No full text in DiVA

By organisation
Medicinsk genetik och genomik
Medical Genetics

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 184 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf