β-hydroxybutyrate is a metabolic regulator of proteostasis in the aged and Alzheimer disease brain.

Loss of proteostasis is a hallmark of aging and Alzheimer disease (AD). We identify β-hydroxybutyrate (βHB), a ketone body, as a regulator of protein solubility. βHB primarily provides ATP substrate during periods of reduced glucose availability, and regulates other cellular processes through protein interactions. We demonstrate βHB-induced protein insolubility is not dependent on covalent protein modification, pH, or solute load, and is observable in mouse brain in vivo after delivery of a ketone ester. This mechanism is selective for pathological proteins such as amyloid-β, and exogenous βHB ameliorates pathology in nematode models of amyloid-β aggregation toxicity. We generate libraries of the βHB-induced protein insolublome using mass spectrometry proteomics, and identify common protein domains and upstream regulators. We show enrichment of neurodegeneration-related proteins among βHB targets and the clearance of these targets from mouse brain. These data indicate a metabolically regulated mechanism of proteostasis relevant to aging and AD.
Competing Interests: Declaration of interests J.C.N. and E.V. hold patents related to molecules described herein, licensed to BHB Therapeutics Ltd and Selah Therapeutics Ltd. J.C.N. and E.V. are co-founders with stock holdings, and BJS holds stock options, in BHB Therapeutics. J.C.N., E.V., and B.S. are co-founders with stock holdings in Selah Therapeutics.
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