Misaligned feeding uncouples daily rhythms within brown adipose tissue and between peripheral clocks.

Extended food consumption during the rest period perturbs the phase relationship between circadian clocks in the periphery and the brain, leading to adverse health effects. Beyond the liver, how metabolic organs respond to a timed hypocaloric diet is largely unexplored. We investigated how feeding schedules impacted circadian gene expression in epididymal white and brown adipose tissue (eWAT and BAT) compared to the liver and hypothalamus. We restricted food to either daytime or nighttime in C57BL/6J male mice, with or without caloric restriction. Unlike the liver and eWAT, rhythmic clock genes in the BAT remained insensitive to feeding time, similar to the hypothalamus. We uncovered an internal split within the BAT in response to conflicting environmental cues, displaying inverted oscillations on a subset of metabolic genes without modifying its local core circadian machinery. Integrating tissue-specific responses on circadian transcriptional networks with metabolic outcomes may help elucidate the mechanism underlying the health burden of eating at unusual times.

Time-restricted feeding mitigates obesity through adipocyte thermogenesis.

Misalignment of feeding rhythms with the light-dark cycle leads to disrupted peripheral circadian clocks and obesity. Conversely, restricting feeding to the active period mitigates metabolic syndrome through mechanisms that remain unknown. We found that genetic enhancement of adipocyte thermogenesis through ablation of the zinc finger protein 423 (ZFP423) attenuated obesity caused by consumption of a high-fat diet during the inactive (light) period by increasing futile creatine cycling in mice. Circadian control of adipocyte creatine metabolism underlies the timing of diet-induced thermogenesis, and enhancement of adipocyte circadian rhythms through overexpression of the clock activator brain and muscle Arnt-like protein-1 (BMAL1) ameliorated metabolic complications during diet-induced obesity. These findings uncover rhythmic creatine-mediated thermogenesis as an essential mechanism that drives metabolic benefits during time-restricted feeding.

ABHD10 is an S-depalmitoylase affecting redox homeostasis through peroxiredoxin-5.

S-Palmitoylation is a reversible lipid post-translational modification that has been observed on mitochondrial proteins, but both the regulation and functional consequences of mitochondrial S-palmitoylation are poorly understood. Here, we show that perturbing the 'erasers' of S-palmitoylation, acyl protein thioesterases (APTs), with either pan-active inhibitors or a mitochondrial-targeted APT inhibitor, diminishes the antioxidant buffering capacity of mitochondria. Surprisingly, this effect was not mediated by the only known mitochondrial APT, but rather by a resident mitochondrial protein with no known endogenous function, ABHD10. We show that ABHD10 is a member of the APT family of regulatory proteins and identify peroxiredoxin-5 (PRDX5), a key antioxidant protein, as a target of ABHD10 S-depalmitoylase activity. We then find that ABHD10 regulates the S-palmitoylation status of the nucleophilic active site residue of PRDX5, providing a direct mechanistic connection between ABHD10-mediated S-depalmitoylation of PRDX5 and its antioxidant capacity.