Reduction of WDR81 impairs autophagic clearance of aggregated proteins and cell viability in neurodegenerative phenotypes

Neurodegenerative diseases are characterized by neuron loss and accumulation of undegraded protein aggregates. These phenotypes are partially due to defective protein degradation in neuronal cells. Autophagic clearance of aggregated proteins is critical to protein quality control, but the underlying mechanisms are still poorly understood. Here we report the essential role of WDR81 in autophagic clearance of protein aggregates in models of Huntington’s disease (HD), Parkinson’s disease (PD) and Alzheimer’s disease (AD). In hippocampus and cortex of patients with HD, PD and AD, protein level of endogenous WDR81 is decreased but autophagic receptor p62 accumulates significantly. WDR81 facilitates the recruitment of autophagic proteins onto Htt polyQ aggregates and promotes autophagic clearance of Htt polyQ subsequently. The BEACH and MFS domains of WDR81 are sufficient for its recruitment onto Htt polyQ aggregates, and its WD40 repeats are essential for WDR81 interaction with covalent bound ATG5-ATG12. Reduction of WDR81 impairs the viability of mouse primary neurons, while overexpression of WDR81 restores the viability of fibroblasts from HD patients. Notably, in Caenorhabditis elegans, deletion of the WDR81 homolog (SORF-2) causes accumulation of p62 bodies and exacerbates neuron loss induced by overexpressed α-synuclein. As expected, overexpression of SORF-2 or human WDR81 restores neuron viability in worms. These results demonstrate that WDR81 has crucial evolutionarily conserved roles in autophagic clearance of protein aggregates and maintenance of cell viability under pathological conditions, and its reduction provides mechanistic insights into the pathogenesis of HD, PD, AD and brain disorders related to WDR81 mutations.

[1]  G. Kroemer,et al.  Biological Functions of Autophagy Genes: A Disease Perspective , 2019, Cell.

[2]  Chonglin Yang,et al.  WDR81 regulates adult hippocampal neurogenesis through endosomal SARA-TGFβ signaling , 2018, Molecular Psychiatry.

[3]  Chonglin Yang,et al.  C. elegans-based screen identifies lysosome-damaging alkaloids that induce STAT3-dependent lysosomal cell death , 2018, Protein & Cell.

[4]  C. Viret,et al.  Novel Insights into NDP52 Autophagy Receptor Functioning. , 2018, Trends in cell biology.

[5]  D. Klionsky,et al.  Cargo recognition and degradation by selective autophagy , 2018, Nature Cell Biology.

[6]  S. Luo,et al.  Suppression of MAPK11 or HIPK3 reduces mutant Huntingtin levels in Huntington's disease models , 2017, Cell Research.

[7]  N. Boddaert,et al.  WDR81 mutations cause extreme microcephaly and impair mitotic progression in human fibroblasts and Drosophila neural stem cells , 2017, Brain : a journal of neurology.

[8]  N. Brunetti‐Pierri,et al.  An extremely severe phenotype attributed to WDR81 nonsense mutations , 2017, Annals of neurology.

[9]  Z. Yue,et al.  Autophagy Receptors and Neurodegenerative Diseases. , 2017, Trends in cell biology.

[10]  F. Alkuraya,et al.  The genetic landscape of familial congenital hydrocephalus , 2017, Annals of neurology.

[11]  S. Luo,et al.  The BEACH-containing protein WDR81 coordinates p62 and LC3C to promote aggrephagy , 2017, The Journal of cell biology.

[12]  S. P. Andrews,et al.  Autophagy and Neurodegeneration: Pathogenic Mechanisms and Therapeutic Opportunities , 2017, Neuron.

[13]  Chonglin Yang,et al.  Protein kinase C controls lysosome biogenesis independently of mTORC1 , 2016, Nature Cell Biology.

[14]  P. Lehner,et al.  A Genetic Screen Identifies a Critical Role for the WDR81‐WDR91 Complex in the Trafficking and Degradation of Tetherin , 2016, Traffic.

[15]  L. Al-Gazali,et al.  Clinical and molecular delineation of dysequilibrium syndrome type 2 and profound sensorineural hearing loss in an inbred Arab family , 2016, American journal of medical genetics. Part A.

[16]  S. Mitani,et al.  Negative regulation of phosphatidylinositol 3-phosphate levels in early-to-late endosome conversion , 2016, The Journal of cell biology.

[17]  A. Gelman,et al.  Huntingtin facilitates selective autophagy , 2015, Nature Cell Biology.

[18]  Fan Wu,et al.  O-GlcNAc-modification of SNAP-29 regulates autophagosome maturation , 2014, Nature Cell Biology.

[19]  S. Jentsch,et al.  Autophagic Clearance of PolyQ Proteins Mediated by Ubiquitin-Atg8 Adaptors of the Conserved CUET Protein Family , 2014, Cell.

[20]  A. Schäffer,et al.  The BEACH Is Hot: A LYST of Emerging Roles for BEACH‐Domain Containing Proteins in Human Disease , 2013, Traffic.

[21]  K. Millen,et al.  WDR81 Is Necessary for Purkinje and Photoreceptor Cell Survival , 2013, The Journal of Neuroscience.

[22]  A. Ballabio,et al.  Gene transfer of master autophagy regulator TFEB results in clearance of toxic protein and correction of hepatic disease in alpha-1-anti-trypsin deficiency , 2013, EMBO molecular medicine.

[23]  P. Cossart,et al.  Selective autophagy degrades DICER and AGO2 and regulates miRNA activity , 2012, Nature Cell Biology.

[24]  Huseyin Boyaci,et al.  Homozygosity mapping and targeted genomic sequencing reveal the gene responsible for cerebellar hypoplasia and quadrupedal locomotion in a consanguineous kindred. , 2011, Genome research.

[25]  N. Mizushima,et al.  The role of Atg proteins in autophagosome formation. , 2011, Annual review of cell and developmental biology.

[26]  Andrea Ballabio,et al.  TFEB Links Autophagy to Lysosomal Biogenesis , 2011, Science.

[27]  K. Caldwell,et al.  Modeling dopamine neuron degeneration in Caenorhabditis elegans. , 2011, Methods in molecular biology.

[28]  A. Cuervo,et al.  Autophagy gone awry in neurodegenerative diseases , 2010, Nature Neuroscience.

[29]  Dimitri Krainc,et al.  The selective macroautophagic degradation of aggregated proteins requires the PI3P-binding protein Alfy. , 2010, Molecular cell.

[30]  S. Lindquist,et al.  α-Synuclein is part of a diverse and highly conserved interaction network that includes PARK9 and manganese toxicity , 2009, Nature Genetics.

[31]  Kostas Vekrellis,et al.  Wild Type α-Synuclein Is Degraded by Chaperone-mediated Autophagy and Macroautophagy in Neuronal Cells* , 2008, Journal of Biological Chemistry.

[32]  D. Klionsky,et al.  Autophagosome formation: core machinery and adaptations , 2007, Nature Cell Biology.

[33]  G. Bjørkøy,et al.  p62/SQSTM1 Binds Directly to Atg8/LC3 to Facilitate Degradation of Ubiquitinated Protein Aggregates by Autophagy* , 2007, Journal of Biological Chemistry.

[34]  R. Kopito,et al.  HDAC6 and Microtubules Are Required for Autophagic Degradation of Aggregated Huntingtin* , 2005, Journal of Biological Chemistry.

[35]  Terje Johansen,et al.  p62/SQSTM1 forms protein aggregates degraded by autophagy and has a protective effect on huntingtin-induced cell death , 2005, The Journal of cell biology.

[36]  Peter T. Lansbury,et al.  Impaired Degradation of Mutant α-Synuclein by Chaperone-Mediated Autophagy , 2004, Science.

[37]  Leonidas Stefanis,et al.  Impaired degradation of mutant alpha-synuclein by chaperone-mediated autophagy. , 2004, Science.

[38]  Jeremy N. Skepper,et al.  α-Synuclein Is Degraded by Both Autophagy and the Proteasome* , 2003, Journal of Biological Chemistry.

[39]  J. Hodgson,et al.  Huntingtin Is Ubiquitinated and Interacts with a Specific Ubiquitin-conjugating Enzyme* , 1996, The Journal of Biological Chemistry.