Rapid generation of a sdhb loss-of-function zebrafish model for secreting pheochromocytomas and paragangliomas
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PROVIDER: PRJNA1282665 | ENA |
REPOSITORIES: ENA
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Project description:Introduction: Genotype constitutes a pivotal factor in the comprehensive management of pheochromocytomas and paragangliomas (PPGLs). This underlines the need to (1) further elucidate the genetic etiology of these pathologies, (2) investigate the underlying pathogenic mechanisms, and (3) identify therapeutic targets. These goals rely on generating and studying relevant biological models, particularly in vivo. However, this has remained a disappointment using traditional animal models. In this context, there is a need to develop fast, reliable in vivo models of PPGLs which display clinically relevant biochemical hallmarks of PPGLs. Objective: Our study aims to establish zebrafish larvae as a relevant and convenient proxy for the functional characterization of PPGL-associated genetic variants. Methods: We took advantage of the genetic accessibility of zebrafish embryos to generate first-generation (F0) loss-of-function models for sdhb, a canonical PPGL-associated gene, using CRISPR/CAS9 technology. F0 zebrafish embryos were microinjected with a CRISPR/CAS9 molecular cocktail containing sdhb-specific guide RNAs and compared with control embryos injected with non-active CRISPR/CAS9. The mutagenic score of our CRISPR/CAS9 approach was validated by High-Resolution Melting analysis, and mutant zebrafish larvae were phenotyped during their first five days of development. Notably, the levels of catecholamines/metanephrines (in whole fish extract and bathing medium) and Krebs cycle metabolites were assessed by liquid chromatography-mass spectrometry. Other relevant phenotypic readouts were also performed, such as heart rate, swimming activity and overall survival. To validate the specificity of our findings, we also analyzed other zebrafish genetic mutants diseased controls (i.e. nf1 CRISPants as PPGL positive controls and scn1a-mutant as non-PPGL negative genetic controls). Finally, we performed an RNA-sequencing assay from sdhb-CRISPant and controls larvae. Results: Sdhb CRISPants exhibit increased heart rates, reduced swimming activity and premature death. In whole fish extracts, normetanephrine (NM), metanephrine (MN), and dopamine (DA) levels were about three times higher in sdhb CRISPants than in control larvae. In the bathing medium, NM and MN were also significantly elevated, along with 3-MT. We confirmed the specificity of our findings by showing that nf1-mutant larvae exhibit similar catecholamine levels but also show an adrenergic phenotype typical of cluster 2 variants of PPGLs. In contrast, scn1a-mutant larvae, despite suffering from severe epileptic encephalopathy associated with reduced lifespan, did not display elevated catecholamine levels. Complementary metabolic profiling showed that sdhb CRISPants depict a clear Complex II dysfunction signature, characterized by elevated succinate, lactate, NAD+, along with reduced aspartate and glutamate levels. Additionally, RNA-sequencing revealed downregulation of sdhb and fads2, and upregulation of genes involved in the hypoxia response, angiogenesis, stress response, and glycolysis in sdhb CRISPants compared to Cas9-control larvae. Conclusion: In this work, we validated the relevance of F0 loss-of-function zebrafish models (CRISPant) to study the pathogenicity of PPGL-causing genetic variants in vivo. We present the first in vivo model of sdhb loss-of-function with oversecretion of free catecholamines, a key clinical hallmark of PPGLs in humans. We also show that other pathological molecular hallmarks are found increased such as Krebs cycle metabolites and relevant phenotypic readouts (tachycardia, reduced lifespan, and consistent transcriptomic dysregulations). These findings suggest that zebrafish is a relevant physiopathologic model for studying PPGLs and their associated genetic etiologies and opens the door for streamlining preclinical precision medicine approaches for PPGLs.
2025-08-20 | GSE300914 | GEO
Project description:Pheochromocytomas are neural crest-derived tumors that arise from inherited or sporadic mutations in at least six independent genes: RET, VHL, NF1, and subunits B, C and D of succinate dehydrogenase (SDH). The proteins encoded by these multiple genes regulate distinct functions. To identify molecular interactions between the distinct pathways we performed expression profiling of a large cohort of pheochromocytomas. We show here a functional link between tumors with VHL mutations and those with disruption of the genes encoding for succinate dehydrogenase (SDH) subunits B (SDHB) and D (SDHD). A transcription profile of reduced oxidoreductase is detected in all three of these tumor types, together with an angiogenesis/hypoxia profile typical of VHL dysfunction. The oxidoreductase defect, not previously detected in VHL-null tumors, is explained by suppression of the SDHB protein, a component of mitochondrial complex II. The decrease in SDHB is also noted in tumors with SDHD mutations. Gain-of-function and loss-of-function analyses show that the link between hypoxia signals (via VHL) and mitochondrial signals (via SDH) is mediated by HIF1?. These findings explain the shared features of pheochromocytomas with VHL and SDH mutations and suggest an additional mechanism for increased HIF1? activity in tumors. Keywords: disease state analysis: Primary sporadic and hereditary pheochromocytomas and paragangliomas
2005-08-12 | GSE2841 | GEO
Project description:A Cartes d'Identité des Tumeurs (CIT) project from the french Ligue Nationale Contre le Cancer (http://cit.ligue-cancer.net) | Affymetrix HG-U133 Plus 2.0 : 188 tumor samples |Pheochromocytomas and paragangliomas are neuroendocrine tumors occuring in the context of inherited cancer syndromes in approximately 30% of cases, linked to germline mutations in VHL, RET, NF1, SDHA, SDHB, SDHC, SDHD, SDHAF2 or TMEM127 genes. Although progress has been made with regard to tumorigenesis mechanisms in pheochromocytoma/paraganglioma thanks to genome-wide expression studies, the question of a putative molecular distinction between VHL- and SDHx- on one hand, and RET- and NF1-related tumors on the other hand, remained to be addressed as well as the characterization of genetic events in sporadic tumors. With this purpose, 202 pheochromocytomas/paragangliomas, including 75 hereditary tumors, were investigated by expression profiling, array CGH and somatic mutation screening. The systematic characterization of somatic genetic events associated with tumor suppressor gene germline mutations in tumor tissues reveals a majority of loss of heterozygosity (LOH) but also point mutations and copy neutral LOH. Gene-expression signature defined the hereditary tumors according to their genotype. Especially, a complete sub-separation between SDHx- and VHL-related tumors was observed. Moreover, guided by the transcriptome classification and the LOH profile, somatic mutations in VHL or RET genes were identified in 14% of sporadic pheochromocytomas/paragangliomas. A genetic cause was found in 45.5% (92/202) of the large series of pheochromocytomas/paragangliomas analyzed. Regarding mutated genes, specific molecular pathways involved in tumorigenesis mechanisms are showed. Altogether, these new findings suggest that somatic mutation analysis would give important clues for personalized molecular target therapies.
2011-07-07 | E-MTAB-733 | biostudies-arrayexpress
Project description:SNP profiles from 78 pheochromocytomas and paragangliomas were analyzed to detect copy number changes and LOH. 78 pheochromocytomas and paragangliomas were analyzed with Illumina Human610-Quad v1.0 BeadChips.
2012-09-11 | E-GEOD-38525 | biostudies-arrayexpress
Project description:SNP profiles from 30 pheochromocytomas and paragangliomas were analyzed to detect identical-by-descent haplotypes, highlighting a founder mutation of SDHD in two samples. 30 pheochromocytomas and paragangliomas were analyzed with Illumina Human610-Quad v1.0 BeadChips.
2012-03-23 | E-GEOD-32204 | biostudies-arrayexpress
Project description:SNP profiles from 78 pheochromocytomas and paragangliomas were analyzed to detect copy number changes and LOH.
2012-09-11 | GSE38525 | GEO
Project description:Effect of SDHB silencing using siRNA methodologies in the tumor phenotype We used microarrays to detail the global programme of gene expression when SDHB is silenced. Keywords: siRNA experiment (loss of function)
2008-04-01 | GSE10289 | GEO
Project description:Pheochromocytomas and paragangliomas (PPGLs) are neuroendocrine tumours affecting a range of body sites and have the highest degree of heritability of any cancer type. SDHA, SDHB, SDHC, SDHD and SDHAF2 (collectively SDHx) code for subunits of succinate dehydrogenase, an enzyme complex in the tricarboxylic cycle that converts succinate to fumarate. Mutations in all SDHx genes play a role in PPGL pathogenesis and completely abolish succinate dehydrogenase enzymatic activity causing intracellular accumulation of oncometabolites which competitively inhibit 2-oxoglutarate-dependent oxygenases. This is a family of enzymes includes TET DNA demethylases and Jumonji C (JmjC) domain-containing histone demethylates. We and others have found that the inhibition of DNA demethylation leads to profound global DNA hypermethylation which influences expression of genes responsible for important clinical characteristics of these tumours but cannot explain the full spectrum of transcriptomic changes. We profiled histone PMTs to complement DNA methylation data and fully characterise the epigenome of these tumours.
2024-01-26 | PXD025689 | Pride
Project description:SNP profiles from 30 pheochromocytomas and paragangliomas were analyzed to detect identical-by-descent haplotypes, highlighting a founder mutation of SDHD in two samples.
2012-03-23 | GSE32204 | GEO
Project description:Effect of SDHB silencing using siRNA methodologies in the tumor phenotype; We used microarrays to detail the global programme of gene expression when SDHB is silenced. Experiment Overall Design: Human hepatocellular carcinoma cell line Hep3B was stably silenced with control or SDHB-specific siRNAs. <br><br>This experiment was re-loaded into ArrayExpress in November 2010 after manual curation.
2008-06-11 | E-GEOD-10289 | biostudies-arrayexpress