Stratifying cellular injury in Alzheimer’s disease by chaperonin containing TCP1 subunits 2 and 3

Chaperonins complex into double-ringed octamers to aid peptide folding. Recent evidence implicates dysfunctional chaperonin subunits in cancer and neurodegenerative diseases because their deregulation exacerbates cellular injury. Nevertheless, a gap of knowledge exists regarding the expression and localization of chaperonin subunits in relation to amyloidogenic processes in Alzheimer’s disease (AD). Here, we show that reduced levels of chaperonin-containing TCP-1 subunits 2 (CCT2) and 3 (CCT3) stratify AD, with the subcellular distribution of their residua being mutually exclusive with both β-amyloid and hyperphosphorylated tau in neurons. We find CCT3 localized to a subset of glial fibrillary acidic protein-positive astrocytes in AD. Increased oxidative stress in vitro upregulated CCT3 expression in astrocyte-like U251 cells. Conversely, CCT3, but not CCT2, loss-of-function in neuron-like SH-SY5Y cells increased intracellular β-amyloid load. These data suggest that CCT2/CCT3 are faithful disease-state indicators and implicate CCT3 in oxidative stress-dependent cellular damage pathways.