OCIAD1 contributes to neurodegeneration in Alzheimer's disease by inducing mitochondria dysfunction, neuronal vulnerability and synaptic damages

EBioMedicine. 2020 Jan;51:102569. doi: 10.1016/j.ebiom.2019.11.030. Epub 2020 Jan 10.

Abstract

Background: Hyperamyloidosis in the brain is known as the earliest neuropathological change and a unique etiological factor in Alzheimer's disease (AD), while progressive neurodegeneration in certain vulnerable brain regions forms the basis of clinical syndromes. It is not clear how early hyperamyloidosis is implicated in progressive neurodegeneration and what factors contribute to the selective brain vulnerability in AD.

Methods: Bioinformatics and experimental neurobiology methods were integrated to identify novel factors involved in the hyperamyloidosis-induced brain vulnerability in AD. We first examined neurodegeneration-specific gene signatures from sporadic AD patients and synaptic protein changes in young transgenic AD mice. Then, we systematically assessed the association of a top candidate gene with AD and investigated its mechanistic role in neurodegeneration.

Findings: We identified the ovary-orientated protein OCIAD1 (Ovarian-Carcinoma-Immunoreactive-Antigen-Domain-Containing-1) as a neurodegeneration-associated factor for AD. Higher levels of OCIAD1, found in vulnerable brain areas and dystrophic neurites, were correlated with disease severity. Multiple early AD pathological events, particularly Aβ/GSK-3β signaling, elevate OCIAD1, which in turn interacts with BCL-2 to impair mitochondrial function and facilitates mitochondria-associated neuronal injury. Notably, elevated OCIAD1 by Aβ increases cell susceptibility to other AD pathological challenges.

Interpretation: Our findings suggest that OCIAD1 contributes to neurodegeneration in AD by impairing mitochondria function, and subsequently leading to neuronal vulnerability, and synaptic damages.

Funding: Ting Tsung & Wei Fong Chao Foundation, John S Dunn Research Foundation, Cure Alzheimer's Fund, and NIH R01AG057635 to STCW.

Keywords: Alzheimer's disease; Hyperamyloidosis; Mitochondrial dysfunction; Neurodegeneration; OCIAD1.

MeSH terms

  • Alzheimer Disease / metabolism
  • Alzheimer Disease / pathology*
  • Amyloid beta-Peptides / metabolism
  • Animals
  • Brain / pathology
  • Caspase 3 / metabolism
  • Cell Death
  • Enzyme Activation
  • F-Box Proteins / metabolism*
  • Glycogen Synthase Kinase 3 beta / metabolism
  • Humans
  • Membrane Potential, Mitochondrial
  • Mice
  • Mice, Transgenic
  • Mitochondria / pathology*
  • Neoplasm Proteins / metabolism*
  • Nerve Degeneration / metabolism*
  • Nerve Degeneration / pathology*
  • Neurons / metabolism*
  • Neurons / pathology
  • Protein Aggregates
  • Protein Binding
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Synapses / pathology*
  • Synapses / ultrastructure
  • Tumor Suppressor Protein p53 / metabolism
  • Up-Regulation

Substances

  • Amyloid beta-Peptides
  • Emi2 protein, mouse
  • F-Box Proteins
  • Neoplasm Proteins
  • Protein Aggregates
  • Proto-Oncogene Proteins c-bcl-2
  • Tumor Suppressor Protein p53
  • ovarian cancer immuno-reactive antigen domain containing 1, human
  • Glycogen Synthase Kinase 3 beta
  • Caspase 3