Circadian clock-dependent and -independent rhythmic proteomes implement distinct diurnal functions in mouse liver

The diurnal variation in acetaminophen (APAP) hepatotoxicity (chronotoxicity) reportedly is driven by oscillations in metabolism that are influenced by the circadian phases of feeding and fasting. To determine the relative contributions of the central clock and the hepatocyte circadian clock in modulating the chronotoxicity of APAP, we used a conditional null allele of brain and muscle Arntlike 1 (Bmal1, aka Mop3 or Arntl) allowing deletion of the clock from hepatocytes while keeping the central and other peripheral clocks (e.g., the clocks controlling food intake) intact. We show that deletion of the hepatocyte clock dramatically reduces APAP bioactivation and toxicity in vivo and in vitro because of a reduction in NADPH-cytochrome P450 oxidoreductase gene expression, protein, and activity.circadian clock | acetaminophen toxicity | NADPH-cytochrome P450 oxidoreductase | chronotoxicity | Bmal1

Section: Discussioncontrasting

confidence: 99%

Hepatocyte circadian clock controls acetaminophen bioactivation through NADPH-cytochrome P450 oxidoreductase

Johnson

Walisser

Liu

et al. 2014

“…We evaluated the impact of rhythmic translation on rhythmic protein levels by comparing mRNA and RFP levels with recently published protein levels (14). As described for rhythmic mRNAs, the majority of rhythmic RFPs encoded nonrhythmic proteins, likely as a consequence of long protein half-lives (Fig.…”

Section: Resultsmentioning

confidence: 99%

Circadian and feeding rhythms differentially affect rhythmic mRNA transcription and translation in mouse liver

Atger

Gobet

Marquis

et al. 2015

Self Cite

212

287

Diurnal oscillations of gene expression are a hallmark of rhythmic physiology across most living organisms. Such oscillations are controlled by the interplay between the circadian clock and feeding rhythms. Although rhythmic mRNA accumulation has been extensively studied, comparatively less is known about their transcription and translation. Here, we quantified simultaneously temporal transcription, accumulation, and translation of mouse liver mRNAs under physiological light-dark conditions and ad libitum or night-restricted feeding in WT and brain and muscle Arnt-like 1 (Bmal1)-deficient animals. We found that rhythmic transcription predominantly drives rhythmic mRNA accumulation and translation for a majority of genes. Comparison of wild-type and Bmal1 KO mice shows that circadian clock and feeding rhythms have broad impact on rhythmic gene expression, Bmal1 deletion affecting surprisingly both transcriptional and posttranscriptional levels. Translation efficiency is differentially regulated during the diurnal cycle for genes with 5′-Terminal Oligo Pyrimidine tract (5′-TOP) sequences and for genes involved in mitochondrial activity, many harboring a Translation Initiator of Short 5′-UTR (TISU) motif. The increased translation efficiency of 5′-TOP and TISU genes is mainly driven by feeding rhythms but Bmal1 deletion also affects amplitude and phase of translation, including TISU genes. Together this study emphasizes the complex interconnections between circadian and feeding rhythms at several steps ultimately determining rhythmic gene expression and translation.circadian rhythms | ribosome profiling | mRNA translation | 5′-TOP sequences | TISU motifs L iving organisms on Earth are subjected to light-dark cycles caused by rotation of the Earth around the sun. To anticipate these changes, virtually all organisms have acquired a circadian timing system during evolution that allows a better adaptation to their environment. As a consequence, most aspects of their physiology are orchestrated in a rhythmic way by the circadian clock (from the Latin circa diem, meaning "about a day"), an endogenous and autonomous oscillator with a period of around 24 h (1, 2). Not surprisingly, perturbations of this clock in mammals lead to pathologies including psychiatric, metabolic, and vascular disorders (1,3,4). At the organismal scale, the oscillatory clockwork is organized in a hierarchal manner. Within the suprachiasmatic nuclei (SCN) of the hypothalamus, the "master clock" receives light input via the retina and communicates timing signals to "enslave" oscillators in peripheral organs (1, 2). The molecular oscillator consists of interconnected transcriptional and translational feedback loops, in which multiple layers of control, including temporal posttranscriptional and posttranslational regulation, play important roles (5). These additional layers of regulation are largely coordinated by systemic cues originating from circadian clock and/or feeding-coordinated rhythmic metabolism, allowing the adjustment of the molecular clo...

“…The difference in the experimental setup may account for some differences in peak time of abundance for RNA and protein. Recent proteomics studies on whole-liver samples already showed that the oscillations of proteins encoded by rhythmically expressed mRNAs greatly differ in their cycling phases (13,15). Thus, although rhythmic transcription is at the core of circadian regulation, it seems that posttranscriptional mechanisms, such as translational control (39,40) and temporal regulation of protein synthesis/degradation (41), play a significant role in shaping the circadian proteome landscape.…”

Section: Discussionmentioning

confidence: 99%

“…In contrast to previous circadian proteomics that were done on whole-liver samples (13,15), we performed herein the proteomics analysis on isolated mitochondria from liver. After stringent filtering, we precisely quantified 590 different mitochondrial-annotated proteins of ∼1,000 known mitochondrial proteins (44).…”

Section: Discussionmentioning

confidence: 99%

“…The core clock molecular circuitry relies on interlocked transcription-translation feedback loops that generate daily oscillations of gene expression in cultured cells and living animals (7). Many transcriptomes (8)(9)(10)(11)(12)) and more recently, several proteomics (13)(14)(15) and metabolomics studies (16)(17)(18)(19)(20)(21) highlighted the pervasive circadian control of metabolism.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Circadian control of oscillations in mitochondrial rate-limiting enzymes and nutrient utilization by PERIOD proteins

Neufeld-Cohen

Robles

Aviram

et al. 2016

205

192

Mitochondria are major suppliers of cellular energy through nutrients oxidation. Little is known about the mechanisms that enable mitochondria to cope with changes in nutrient supply and energy demand that naturally occur throughout the day. To address this question, we applied MS-based quantitative proteomics on isolated mitochondria from mice killed throughout the day and identified extensive oscillations in the mitochondrial proteome. Remarkably, the majority of cycling mitochondrial proteins peaked during the early light phase. We found that rate-limiting mitochondrial enzymes that process lipids and carbohydrates accumulate in a diurnal manner and are dependent on the clock proteins PER1/2. In this conjuncture, we uncovered daily oscillations in mitochondrial respiration that peak during different times of the day in response to different nutrients. Notably, the diurnal regulation of mitochondrial respiration was blunted in mice lacking PER1/2 or on a high-fat diet. We propose that PERIOD proteins optimize mitochondrial metabolism to daily changes in energy supply/demand and thereby, serve as a rheostat for mitochondrial nutrient utilization.M itochondria serve as major suppliers of cellular energy through nutrient oxidation. One of the major challenges that mitochondria face is the adaptation to changes in nutrient supply and energy demand. An inability of mitochondria to deal with altered nutrient environment is associated with metabolic diseases, such as diabetes and obesity (1, 2).Mitochondria oxidize carbohydrates and lipids to generate ATP by a process known as oxidative phosphorylation. Pyruvate and fatty acids are transported from the cytoplasm into the mitochondrial matrix, where they are catabolized into acetyl CoA. Pyruvate is converted to acetyl CoA through the action of the pyruvate dehydrogenase complex (PDC), whereas fatty acids are oxidized through a cycle of reactions that trim two carbons at a time, generating one molecule of acetyl CoA in each cycle [i.e., fatty acid oxidation (FAO)]. The acetyl groups are then fed into the Krebs cycle for additional degradation, and the process culminates with the transfer of acetyl-derived high-energy electrons along the respiratory chain.Mounting evidence suggests that circadian clocks orchestrate our daily physiology and metabolism (3-6). The mammalian circadian timing system consists of a central pacemaker in the brain that is entrained by daily light-dark cycles and synchronizes subsidiary oscillators in virtually all cells of the body, in part by driving rhythmic feeding behavior. The core clock molecular circuitry relies on interlocked transcription-translation feedback loops that generate daily oscillations of gene expression in cultured cells and living animals (7). Many transcriptomes (8-12) and more recently, several proteomics (13-15) and metabolomics studies (16-21) highlighted the pervasive circadian control of metabolism.Rest-activity and feeding-fasting cycles that naturally occur throughout the day impose pronounced changes in nutrient s...