RNA exosome mutations in pontocerebellar hypoplasia alter ribosome biogenesis and p53 levels
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA635887 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:The eukaryotic RNA exosome is a ubiquitously expressed complex of nine core proteins (EXOSC1-9) and associated nucleases responsible for RNA processing and degradation. Autosomal recessive mutations in EXOSC3, EXOSC8, EXOSC9 and the exosome cofactor RBM7 cause pontocerebellar hypoplasia and motor neuronopathy. To understand the importance of the exosome in neurodegeneration, we investigated the consequences of exosome mutations on RNA metabolism and cellular survival in zebrafish and human cell models. We observed that levels of mRNAs encoding p53 and ribosome biogenesis factors are upregulated in zebrafish lines with homozygous mutations of exosc8 or exosc9, respectively. In addition, exosome deficiency leads to increased levels of multiple non-coding RNAs (e.g. tRNAs, snoRNAs, scaRNAs). Consistent with higher p53 levels, mutant zebrafish have a reduced head size, smaller brain and cerebellum caused by an increased number of apoptotic cells during development. Downregulation of EXOSC9 in human cells leads to p53 protein stabilisation and G2/M cell cycle arrest. The work provides explanation for the pathogenesis of exosome-related disorders and highlights the link between exosome function, ribosome biogenesis and p53-dependent signalling.
2020-05-30 | GSE151452 | GEO
Project description: Not available
| S-EPMC7295610 | biostudies-literature
Project description:Recessive mutations in EXOSC3, encoding a subunit of the human RNA exosome complex, cause Pontocerebellar hypoplasia type 1b (PCH1B). We report a boy with severe muscular hypotonia, psychomotor retardation, progressive microcephaly, and cerebellar atrophy. Biochemical abnormalities comprised mitochondrial Complex I and PDHc deficiency. Whole exome sequencing uncovered a known EXOSC3-mutation p.(D132A) as the underlying cause. In patient fibroblasts, >50% of the EXOSC3 protein was trapped in the cytosol. mtDNA-copy numbers in muscle were reduced to 40%, but mutations in the mtDNA and nuclear mitochondrial genes were excluded. RNA-seq of patient muscle showed highly increased mRNA-copy numbers, especially for genes encoding structural subunits of OXPHOS-complexes I, III, and IV, possibly due to reduced degradation by a dysfunctional exosome complex. This is the first case of mitochondrial dysfunction associated with an EXOSC3 mutation, which expands the phenotypic spectrum of PCH1B. We discuss the links between exosome and mitochondrial dysfunction.
2017-08-22 | GSE99715 | GEO
Project description:A Drosophila Model of Pontocerebellar Hypoplasia Reveals a Critical Role for the RNA Exosome in Neurons
| PRJNA612828 | ENA
Project description:RNA exosomopathies, a growing family of tissue-specific diseases, are linked to missense mutations in genes encoding the structural subunits of the conserved 10-subunit exoribonuclease complex, the RNA exosome. Such mutations in the cap subunit gene EXOSC2 cause the novel syndrome SHRF (Short stature, Hearing loss, Retinitis pigmentosa and distinctive Facies). In contrast, exosomopathy mutations in the cap subunit gene EXOSC3 cause pontocerebellar hypoplasia type 1b (PCH1b). Though having strikingly different disease pathologies, EXOSC2 and EXOSC3 exosomopathy mutations result in amino acid substitutions in similar, conserved domains of the cap subunits, suggesting that these exosomopathy mutations have distinct consequences for RNA exosome function. We generated the first in vivo model of the SHRF pathogenic amino acid substitutions using budding yeast by introducing the EXOSC2 mutations in the orthologous S. cerevisiae gene RRP4. The resulting rrp4 mutant cells have defects in cell growth and RNA exosome function. We detect significant transcriptomic changes in both coding and non-coding RNAs in the rrp4 variant, rrp4-G226D, which models EXOSC2 p.Gly198Asp. Comparing this rrp4-G226D mutant to the previously studied S. cerevisiae model of EXOSC3 PCH1b mutation, rrp40-W195R, reveals that these mutants have disparate effects on certain RNA targets, providing the first evidence for different mechanistic consequences of these exosomopathy mutations. Congruently, we detect specific negative genetic interactions between RNA exosome cofactor mutants and rrp4-G226D but not rrp40-W195R. These data provide insight into how SHRF mutations could alter the function of the RNA exosome and allow the first direct comparison of exosomopathy mutations that cause distinct pathologies.
2020-12-14 | GSE163106 | GEO
Project description:RNA-binding proteins (RBPs) are key mediators of RNAbiogenesis and metabolism. An RBP can be dedicated to a specific transcript class (e.g. mRNAs) or function broadly across both coding and non-coding RNAs. Consequently, nuclear RNA homeostasis requires maintenance of bothRBP binding specificity and the proper distribution of RBP activity across multiple transcript classes. In S. cerevisiae, mutation of an RBP that functions in ribosome biogenesis, Enp1, was previously found to have terminal phenotypes similar to exosome or TRAMP mutants that extended beyond ribosomal RNA processing defects. Here, we show through proteomicand RNomic analyses that enp1-1 cells have stabilized polyadenylated pre-rRNAs that bind and sequester RBPs in the nucleolus, including the poly(A)-binding protein (PABP) Nab2. Changes in nucleolar polyadenylated RNA levels and PABP availability are further accompanied by transcriptome-wide changes in RNA biogenesis in enp1-1 cells, including increased levels of pervasive transcripts and snoRNA processing defects. The observed changes in RNA processing can be mitigated if enp1-1 cells are provided excess PABP activity through overexpression of Nab2 or Pab1. Together, these findings indicate that generation of excess nucleolar poly(A)-RNA is toxic to the cell, disrupting nuclear RNA processing homeostasis through sequestering RBPs, including the PABP Nab2.
2020-10-08 | PXD021855 | Pride
Project description:Exosomes transport a variety of macromolecules and modulate intercellular communication in physiology and disease. However, the regulation mechanisms that determine exosome contents during exosome biogenesis remain poorly understood. Here, we identify GPR143, an atypical GPCR, as a regulator of the endosomal sorting complex required for transport (ESCRT)-dependent exosome biogenesis pathway. GPR143 interacts with HRS (an ESCRT-0 Subunit) and promotes its association to cargo proteins, such as EGFR, which subsequently enables selective protein sorting into intralumenal vesicles (ILVs) in multivesicular bodies (MVBs). GPR143 is elevated in multiple cancers and quantitative proteomic and RNA profiling of exosomes revealed the GPR143-ESCRT pathway promotes secretion of exosomes that carry unique cargo, including integrins signaling proteins. By gain- and loss-of-function studies, we reveal GPR143 promotes metastasis by secreting exosomes and increasing cell motility/invasion through the integrin/FAK/Src pathway. These finding uncover a mechanism that regulates the exosomal proteome and demonstrate its ability to promote cancer metastasis.
2022-12-20 | PXD031515 | Pride
Project description:In all domains of life, the rate of protein synthesis is directly linked to the rates of cell growth and proliferation. Consequently, highly proliferative cancer cells are especially sensitive to perturbations in ribosome biogenesis. While ribosome synthesis and cancer have a well-established relationship, only recently has ribosome biogenesis drawn interest as a cancer therapeutic target. Here, we have exploited the relationship between ribosome biogenesis and cancer cell proliferation by using a potent ribosome biogenesis inhibitor: RBI2 (Ribosome Biogenesis Inhibitor 2) to perturb cancer cell growth and viability. We demonstrate that RBI2 significantly decreases cell viability in malignant melanoma cells and breast cancer cell lines. Treatment with RBI2 dramatically and rapidly decreases ribosomal RNA (rRNA) synthesis, without affecting the occupancy of RNA polymerase I (Pol I) on the ribosomal DNA template. Next-generation RNA sequencing (RNA-seq) reveals that RBI2 and previously described ribosome biogenesis inhibitor CX-5461 induce distinct changes in the transcriptome. Investigation of the content of the pre-rRNAs through RT-qPCR reveals an increase in polyadenylation of cellular rRNA after treatment with RBI2, a known pathway by which rRNA degradation occurs. Northern blotting revealed that RBI2 does not appear to impair or alter rRNA processing. Collectively, these data suggest that RBI2 inhibits rRNA synthesis distinctly from other previously described ribosome biogenesis inhibitors, potentially through a novel pathway that upregulates turnover of premature rRNAs.
2021-11-08 | GSE188262 | GEO
Project description:Colorectal cancer (CRC) liver metastasis is the main cause of cancer-related mortality. The mechanisms by which cancer cells regulate liver microenvironment to promote cancer liver metastasis have been extensively studied. However, how the liver influences intercellular communication to support tumor liver metastasis remains largely unknown. Here, we link GP73, whose chronic upregulation in hepatocytes triggers non-obese NAFLD in mice, with exosome biogenesis and hence cancer liver metastasis. Plasma GP73 level and liver GP73 protein expression were significantly elevated in CRC patients with liver metastasis (CRLM) as compared with CRC patients without liver metastasis. Strikingly, mice with high liver GP73 expression induced by Ad5-GP73 injection exhibited significantly increased CRC liver metastasis in an exosome dependent manner. Notably, GP73 overlapped with endosomal compartments and promoted exosome production. Mechanistically, GP73 bound to cholesterol and modulated the cholesterol content in endosomal compartments/multivesicular bodies (MVBs). Quantitative proteomics profiling revealed that GP73 reshaped hepatocyte exosomal proteome and produces NAV2-containing exosomes. Clinically, serum GP73 levels correlated positively with serum exosome NAV2 levels in CRLM. In particular, exosomes from GP73-high livers promoted tumor cell invasiveness mainly through transferable NAV2. Knockdown liver NAV2 suppressed enhanced CRC liver metastasis in GP73-induced non-obese mice, and GP73 blockade significantly mitigated CRC liver metastasis enhancement in obese mice resulting from high-fat diet (HFD) or high-fructose diet (HFrD) feeding. Collectively, our findings provide novel insight into the roles of GP73 in exosome biogenesis and GP73 blockade may merit exploration as a potential therapeutic strategy for mitigating CRC liver metastasis.
2023-06-13 | PXD042963 | iProX
Project description:Purine biosynthesis and metabolism, conserved in all living organisms, is essential for cellular energy homeostasis and nucleic acids synthesis. The de novo synthesis of purine precursors is under tight negative feedback regulation mediated by adenine and guanine nucleotides. We describe a new early-onset distinct neurodegenerative condition resulting from mutations in the adenosine monophosphate deaminase 2 gene (AMPD2). Patients have characteristic brain imaging features of pontocerebellar hypoplasia (PCH), due to loss of brainstem and cerebellar parenchyma. We found that AMPD2 plays an evolutionary conserved role in the maintenance of cellular guanine nucleotide pools by regulating the feedback inhibition of adenosine derivatives on de novo purine synthesis. AMPD2 deficiency results in defective GTP-dependent initiation of protein translation, which can be rescued by administration of purine precursors. These data suggest AMPD2-related PCH as a new potentially treatable early-onset neurodegenerative disease. An 18 chip study, that compares iPSC derived neural progenitor cells from two individuals: a patient with pontocerebellar hypoplasia and an unaffected parent. Samples are run as either non-treated, treated with Adenosine, or treated with Adenosine and AICAr. Three replicates are included for every individuals in every treatment condition.
2013-12-01 | E-GEOD-46615 | biostudies-arrayexpress