Polyphenolic flavonoid (Myricetin) upregulated proteasomal degradation mechanisms: Eliminates neurodegenerative proteins aggregation.

TLDR: It is shown that Myricetin, a flavonoid, can eliminate various abnormal proteins from the cellular environment via modulating endogenous levels of Hsp70 chaperone and quality control (QC)‐E3 ubiquitin ligase E6‐AP and reduce the misfolded proteins inclusions, which further alleviates cytotoxicity.

Abstract: Major neurodegenerative disorders are characterized by the formation of misfolded proteins aggregates inside or outside the neuronal cells. Previous studies suggest that aberrant proteins aggregates play a critical role in protein homeostasis imbalance and failure of protein quality control (PQC) mechanism, leading to disease conditions. However, we still do not understand the precise mechanisms of PQC failure and cellular dysfunctions associated with neurodegenerative diseases caused by the accumulation of protein aggregates. Here, we show that Myricetin, a flavonoid, can eliminate various abnormal proteins from the cellular environment via modulating endogenous levels of Hsp70 chaperone and quality control (QC)-E3 ubiquitin ligase E6-AP. We have observed that Myricetin treatment suppresses the aggregation of different aberrant proteins. Myricetin also enhances the elimination of various toxic neurodegenerative diseases associated proteins from the cells, which could be reversed by the addition of putative proteasome inhibitor (MG132). Remarkably, Myricetin can also stabilize E6-AP and reduce the misfolded proteins inclusions, which further alleviates cytotoxicity. Taken together these findings suggested that new mechanistic and therapeutic insights based on small molecules mediated regulation of disturbed protein quality control mechanism, which may result in the maintenance of the state of proteostasis.