Breast cancer type 1 and neurodegeneration: consequences of deficient DNA repair

Abstract

Numerous cellular processes including toxic protein aggregation and oxidative stress have been studied extensively as potential mechanisms underlying neurodegeneration. However, limited therapeutic efficacy targeting these processes has prompted other mechanisms to be explored. Previous research has emphasized a link between cellular senescence and neurodegeneration, where senescence induced by excess DNA damage and deficient DNA repair results in structural and functional changes that ultimately contribute to brain dysfunction and increased vulnerability for neurodegeneration. Specific DNA repair proteins, such as BRCA1, have been associated with both stress-induced senescence and neurodegenerative diseases, however specific mechanisms remain unclear. Therefore, this review explores DNA damage-induced senescence in the brain as a driver of neurodegeneration, with particular focus on BRCA1, and its potential contribution to sex-specific differences associated with neurodegenerative disease.

Cellular Senescence in Traumatic Brain Injury: Evidence and Perspectives

“…Additionally, as this study identified reduced DNA repair pathways in the injured brain, this study suggests that inefficient DNA repair may further confer susceptibility to brain dysfunction after TBI. This poses important questions for understanding risk factors, as many DNA repair factors are naturally polymorphic or may be affected by factors such as sex (Fischer and Riddle, 2018 ; Leung and Hazrati, 2021 ), age (Fischer and Riddle, 2018 ), and lifestyle factors such as substance use (Madden et al, 1979 ).…”

Inflammaging, cellular senescence, and cognitive aging after traumatic brain injury

“…Oxidative stress and genotoxic damage are key initiators of senescence. Consistent with this possibility, the polymorphic nature of DNA repair factors and sex-differences in genomic instability may be responsible for the clinical heterogeneity in outcomes after TBI ( Fischer and Riddle, 2018 ; Leung and Hazrati, 2021 ). Thus, proactive targeting of the early genotoxic stress response may restrain the initiation of cellular senescence/SASP as a “first domino” that potentiates progressive neurodegeneration at all levels of TBI.…”

Gray matter volume in women with the BRCA mutation with and without ovarian removal

“…This suggests that the BRCA mutation, itself, is detrimental to brain integrity. A number of in vitro studies have shown that BRCA1 both 1) accumulates in AD pathologies and tauopathies in general 17,22,24 and 2) is generally reduced in patients with AD 17,20,21,24 . Additionally, reductions of BRCA1 within the brain may be related to learning and memory deficits in mixed-sexed rodents 21,24 .…”

“…While there is less evidence for BRCA2 and dementia, it has been proposed that loss of the BRCA2-mediated DNA repair mechanism may lead to neurodegeneration 19 . Thus, in addition to increased risk due to the sudden loss of E2, there is evidence from both in vitro and in vivo rodent and human studies suggesting that carrying BRCAm may further increase the risk of developing late life dementia 17,[20][21][22]24 . Our results in this regard are very preliminary but support the previous literature on BRCAm and brain changes and raise the interesting possibility that women with the BRCA mutation and BSO may grapple with a double indemnity: issues with gene repair and E2 loss.…”

“…Specifically, in women with BRCAm, BSO prior to age 51 has been shown to reduce the risk of developing ovarian, fallopian, and peritoneal cancers by 80% 15 and breast cancer by 50% 16 . Both BRCA1 and BRCA2 are tumor suppressor genes that play important roles in DNA repair [17][18][19][20][21][22][23][24] . While currently there are no studies investigating how E2 loss and the BRCA mutations might intersect to exacerbate neural changes in younger women, we wondered whether carrying BRCAm would, itself, be correlated with changes in regional brain volumes.…”