Project description:Amyotrophic lateral sclerosis (ALS) involves the degeneration of brain and spinal cord motor neurons. Mutations in Superoxide Dismutase 1 (SOD1), TAR DNA-binding protein 43 (TDP-43) and Fused-in-Sarcoma (FUS) account for 20-30 % of the familial ALS (fALS) cases. The RNA-binding proteins TDP-43 and FUS function in mRNA and miRNA biogenesis. MiRNAs are required for survival of neurons and deregulation of miRNA expression has been reported in several neurodegenerative disorders. Here, we report the dysregulation of DROSHA, DGCR8, and DICER in human neuroblastoma SH-SY5Y cells expressing the ALS-associated SOD1(G93A) mutant protein. MiRNA profiling in SH-SY5Y/SOD1(G93A) cells and transgenic SOD1(G93A) mice revealed upregulation of miR-129-5p at the early stage of disease. Moreover, miR-129-5p is also upregulated in lymphocytes of sporadic ALS patients. We demonstrate that miR-129-5p targets ELAVL4/HuD mRNA by binding to its 3’ UTR, which reduces HuD expression and impairs differentiation and neurite outgrowth. Conversely, treatment with an antagomir or complementation with HuD protein restores neuritogenesis. Collectively, our study identifies miR-129-5p and HuD as key regulators of neuronal differentiation and as potential therapeutic targets for ALS.
Project description:Determination of RNAs bound by wildtype and P525L mutant FUS in human iPSC-derived motoneurons using PAR-CLIP (Photoactivatable Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation)
Project description:Amyotrophic lateral sclerosis (ALS) has been genetically linked to mutations in RNA-binding proteins (RBPs), including FUS. Here, we report the RNA interactome of wild-type and mutant FUS in human motor neurons (MNs). This analysis identified a number of RNA targets. Whereas the wild-type protein preferentially binds introns, the ALS mutation causes a shift toward 3' UTRs. Neural ELAV-like RBPs are among mutant FUS targets. As a result, ELAVL4 protein levels are increased in mutant MNs. ELAVL4 and mutant FUS interact and co-localize in cytoplasmic speckles with altered biomechanical properties. Upon oxidative stress, ELAVL4 and mutant FUS are engaged in stress granules. In the spinal cord of FUS ALS patients, ELAVL4 represents a neural-specific component of FUS-positive cytoplasmic aggregates, whereas in sporadic patients it co-localizes with phosphorylated TDP-43-positive inclusions. We propose that pathological mutations in FUS trigger an aberrant crosstalk with ELAVL4 with implications for ALS.
Project description:The neuronal ELAV-like RNA-binding protein HuD (ELAVL4) plays important roles in multiple post-transcriptional regulatory processes, including RNA stability, transport and translation. Besides its functional role in neuronal plasticity, HuD has been implicated in peripheral axon injury recovery and motor neuronal function. The characterization of HuD specific interactions has always been a challenging task due to the high similarity of sequence and structure with the other members of the ELAVL family, and the lack of specific antibodies. To selectively identify in vivo HuD binding sites, we adapted the CRAC protocol (cross-linking and analysis of cDNAs), originally developed for yeast, to be used with mouse motor neuron NSC-34 cells engineered with inducible tagged HuD. In parallel, to characterize the role of HuD in post-transcriptional regulation, we also profiled the transcriptome (total RNA, RNA-Seq), the translatome (polysomal RNA, POL-Seq) and the alternative polyadenilation (APA, 3’end mRNA sequencing) of HuD induced and control NSC-34 cells. Keywords: HuD, Elavl4, Y3, Rny3, CRAC, RNA interactome, RNA binding, NSC-34, transcriptome profiling, translatome profiling, RNA-Seq, POL-Seq, motor neuron
Project description:We employ CLIP-Seq, RNA-Seq and Ribo-Seq in cultured neurons expressing R495X or wild-type FUS to identify effects of the mutation on the FUS targetome and on the neuronal transcriptome at the expression and translation level
Project description:Amyotrophic lateral sclerosis type 6 (ALS6) is a familial subtype of ALS linked to Fused in Sarcoma (FUS) gene mutation. FUS mutations lead to decreased global protein synthesis, but the mechanism that drives this has not been established. Here, we used ALS6 patient-derived induced pluripotent stem cells (hIPSCs) to study the effect of the ALS6 FUSR521H mutation on the translation machinery in motor neurons (MNs). We find, in agreement with findings of others, that protein synthesis is decreased in ALS6 MNs. Furthermore, ALS6 MNs are more sensitive to oxidative stress and display reduced expression of TGF-β and mTORC gene pathways when stressed. Finally, we show that IFNγ treatment reduces apoptosis of ALS6 MNs exposed to oxidative stress and partially restores the translation rates in ALS6 MNs. Overall, these findings suggest that a functional IFNγ response is important for FUS-mediated protein synthesis, possibly by FUS nuclear translocation in ALS6.
Project description:Mutations in the RNA-binding protein FUS have been genetically linked to Amyotrophic Lateral Sclerosis (ALS), a neurodegenerative disease caused by the death of motoneurons (MNs). FUS is a ubiquitous protein and the mechanisms leading to selective MN loss downstream of FUS mutations are still largely unknown. We report the first transcriptome analysis of human purified MNs, obtained from isogenic induced Pluripotent Stem Cells (iPSCs) with a FUS wild-type or mutant genetic background. Gene ontology analysis of differentially expressed genes identified significant enrichment of pathways previously associated to other neurological diseases and non-FUS ALS, suggesting a common pathological mechanism. We also found several microRNAs deregulated in FUS mutant MNs and focused on miR-375 and miR-125b. Notably, miR-125b is a neural-enriched microRNA with multiple functions in the nervous system and miR-375 had been previously associated to MN survival. We report that relevant targets of both microRNAs, including the neural RNA-binding protein ELAVL4 and apoptosis factors such as p53, are aberrantly increased in FUS mutant MNs. Characterization of FUS RNA targets in the cell type primarily affected by the disease contributes to the definition of the pathogenic mechanisms of FUS-linked ALS.
Project description:We have identified a novel de novo variation in FUS gene in a sporadic juvenile ALS patient. FUS is an RNA-binding protein actively involved in various aspect of nucleic acid metabolism. We performed RNA-seq to identify altered transcriptome in juvenile ALS.
Project description:Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and fatal disease. Although astrocytes are increasingly recognized contributors to the underlying pathogenesis, the uniformity of their reactive transformation in different genetic forms of ALS remains unresolved. Here we begin to systematically examine this issue by performing RNA sequencing on highly enriched and serum-free human induced pluripotent stem cell derived astrocytes from patients with VCP, SOD1 and FUS mutations. The RNA-seq samples in this collection have been used to reveal that diverse fALS mutations lead to molecularly distinct reactive transformation in their basal state.