title: Hu antigen R (HuR) is a positive regulator of the RNA-binding proteins TDP-43 and FUS/TLS: implications for amyotrophic lateral sclerosis.
abstract: Posttranscriptional gene regulation is governed by a network of RNA-binding proteins (RBPs) that interact with regulatory elements in the mRNA to modulate multiple molecular processes, including splicing, RNA transport, RNA stability, and translation. Mounting evidence indicates that there is a hierarchy within this network whereby certain RBPs cross-regulate other RBPs to coordinate gene expression. HuR, an RNA-binding protein we linked previously to aberrant VEGF mRNA metabolism in models of SOD1-associated amyotrophic lateral sclerosis, has been identified as being high up in this hierarchy, serving as a regulator of RNA regulators. Here we investigated the role of HuR in regulating two RBPs, TDP-43 and FUS/TLS, that have been linked genetically to amyotrophic lateral sclerosis. We found that HuR promotes the expression of both RBPs in primary astrocytes and U251 cells under normal and stressed (hypoxic) conditions. For TDP-43, we found that HuR binds to the 3' untranslated region (UTR) and regulates its expression through translational efficiency rather than RNA stability. With HuR knockdown, there was a shift of TDP-43 and FUS mRNAs away from polysomes, consistent with translational silencing. The TDP-43 splicing function was attenuated upon HuR knockdown and could be rescued by ectopic TDP-43 lacking the 3' UTR regulatory elements. Finally, conditioned medium from astrocytes in which HuR or TDP-43 was knocked down produced significant motor neuron and cortical neuron toxicity in vitro. These findings indicate that HuR regulates TDP-43 and FUS/TLS expression and that loss of HuR-mediated RNA processing in astrocytes can alter the molecular and cellular landscape to produce a toxic phenotype.
authors.affiliation: Departments of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294; Departments of Genetics, University of Alabama at Birmingham, Birmingham, Alabama 35294; Birmingham Veterans Affairs Medical Center, Birmingham, Alabama 35294, and. Electronic address: luliang@uab.edu.
authors.forename: Liang
authors.initials: L
authors.lastname: Lu
authors.affiliation: Departments of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294.
authors.forename: Lei
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Departments of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294.
authors.forename: Ying
authors.initials: Y
authors.lastname: Si
authors.affiliation: Departments of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294.
authors.forename: Wenyi
authors.initials: W
authors.lastname: Luo
authors.affiliation: Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires, Buenos Aires C1428EHA, Argentina.
authors.forename: Gwendal
authors.initials: G
authors.lastname: Dujardin
authors.affiliation: Departments of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294.
authors.forename: Thaddaeus
authors.initials: T
authors.lastname: Kwan
authors.affiliation: Departments of Microbiology, and University of Alabama at Birmingham, Birmingham, Alabama 35294.
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Potochick
authors.affiliation: Departments of Microbiology, and University of Alabama at Birmingham, Birmingham, Alabama 35294.
authors.forename: Sunnie R
authors.initials: SR
authors.lastname: Thompson
authors.affiliation: Departments of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama 35294.
authors.forename: David A
authors.initials: DA
authors.lastname: Schneider
authors.affiliation: Departments of Neurology, University of Alabama at Birmingham, Birmingham, Alabama 35294; Departments of Genetics, University of Alabama at Birmingham, Birmingham, Alabama 35294; Departments of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294; Birmingham Veterans Affairs Medical Center, Birmingham, Alabama 35294, and.
authors.forename: Peter H
authors.initials: PH
authors.lastname: King
mesh_terms: D020413:3' Untranslated Regions; D000690:Amyotrophic Lateral Sclerosis / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000166:cytology; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival; D017077:Culture Media, Conditioned / Q000737:chemistry; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D051959:ELAV Proteins / Q000378:metabolism*; D000067780:ELAV-Like Protein 1; D005786:Gene Expression Regulation; D006801:Humans; D000860:Hypoxia; D051379:Mice; D009046:Motor Neurons / Q000378:metabolism; D010641:Phenotype; D012313:RNA / Q000737:chemistry; D034702:RNA-Binding Protein FUS / Q000378:metabolism*
chemical_list: D020413:3' Untranslated Regions; C505032:CFTR protein, human; D017077:Culture Media, Conditioned; D004268:DNA-Binding Proteins; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D034702:RNA-Binding Protein FUS; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D012313:RNA
keywords: 3′ Untranslated Region; Amyotrophic Lateral Sclerosis (ALS) (Lou Gehrig Disease); Astrocyte; Neuron; RNA Processing; RNA Splicing