H63D variant of the homeostatic iron regulator (HFE) gene alters α-synuclein expression, aggregation, and toxicity

Pathological features of Parkinson's disease include the formation of Lewy bodies containing α‐synuclein and the accumulation of iron in the substantia nigra. Previous studies have suggested that iron accumulation contributes to the Parkinson's disease pathology through reactive oxygen species production and accelerated α‐synuclein aggregation. This study examines the effects of commonly occurring H63D variant of the homeostatic iron regulatory (HFE) gene on α‐synuclein pathology in cell culture and animal models. H63D HFE expression in SH‐SY5Y cells lowered endogenous α‐synuclein levels and significantly decreased pre‐formed fibril‐induced α‐synuclein aggregation. H63D HFE cells were also protected from pre‐formed fibril‐induced apoptosis. Autophagic flux, a major pathway for α‐synuclein clearance, was increased in H63D HFE cells. Expression of REDD1 was elevated and rapamycin treatment was unable to further induce autophagy, indicating mTORC1 inhibition as the main mechanism of autophagy induction. Moreover, siRNA knockdown of REDD1 in H63D HFE cells decreased autophagic flux and increased the sensitivity to PFF‐mediated toxicity. While iron chelator (deferiprone) treatment rescued WT HFE cells from pre‐formed fibril toxicity, it exacerbated or was unable to rescue H63D HFE cells. In the in vivo pre‐formed fibril intracranial injection model, H67D Hfe (mouse homolog of the human H63D HFE variant) C57BL/6J × 129 mice showed less α‐synuclein aggregation and less decline in motor function compared to WT Hfe. Collectively, this study suggests that H63D HFE variant modifies α‐synuclein pathology through the induction of autophagy and has the potential to impact the pathogenesis and treatment response in Parkinson's disease.

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Work Title H63D variant of the homeostatic iron regulator (HFE) gene alters α-synuclein expression, aggregation, and toxicity
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Open Access
Creators
  1. Yunsung Kim
  2. Mark C. Stahl
  3. Xuemei Huang
  4. James R. Connor
License In Copyright (Rights Reserved)
Work Type Article
Publisher
  1. Journal of Neurochemistry
Publication Date June 23, 2020
Publisher Identifier (DOI)
  1. 10.1111/jnc.15107
Deposited March 17, 2021

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Version 1
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  • Created
  • Added Creator Yunsung Kim
  • Added Creator Mark C. Stahl
  • Added Creator Xuemei Huang
  • Added Creator James R. Connor
  • Added alphaSynHFE_manuscript_FINAL2.docx
  • Added Figure1_AnimalTimeline.tiff
  • Added Figure2_BaselinASyn.tiff
  • Added Figure3_PFFICC.WB.tiff
  • Added Figure4_CellDeath.tiff
  • Added Figure5_LC3Baseline.tiff
  • Added Figure6_REDD1.tiff
  • Added Figure7_DFP.tiff
  • Added Figure8_MousePFFInjection.tiff
  • Added Supplemental_figures.docx
  • Updated Work Title, License Show Changes
    Work Title
    • H63D variant of the homeostatic iron regulator (HFE) gene alters -synuclein expression, aggregation, and toxicity
    • H63D variant of the homeostatic iron regulator (HFE) gene alters α-synuclein expression, aggregation, and toxicity
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    • https://rightsstatements.org/page/InC/1.0/
  • Deleted Creator Mark C. Stahl
  • Published
  • Added Creator Mark C. Stahl
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  • Updated