bims-ciryme 2026-09-20 papers

J Biol Rhythms. 2026 Sep 15. 7487304261480978

Cell-Autonomous and Systemic Circadian Regulation of Gene Expression in Adipocytes.

Jennifer M Worthen, Armina-Lyn M Frederick, Phillip A Dumesic, Jennifer J Loros, Jay C Dunlap.

Circadian clocks strongly influence adipocyte biology. Studying adipocyte circadian regulation in the absence of organismal cues isolates cell-autonomous clock control, providing insight into mechanisms relevant to metabolic disease. To resolve circadian core biological programs, we deeply sequenced bulk RNA from inguinal-derived, in vitro-differentiated adipocytes (IVDAs) over a 2.5-day circadian time-course and compared clock-controlled genes (CCGs) with existing mouse supraclavicular brown adipose tissue (BAT) and epididymal white adipose tissue (eWAT) circadian time-course datasets. Using Phase Set Enrichment Analysis (PSEA), we report that 21% of the protein-coding transcriptome is rhythmic in IVDAs. Intrinsic circadian regulation governs key processes in energy metabolism, molecular transport, and transcription. Integration with in vivo datasets reveals that BAT and IVDAs exhibit more cohesive rhythmic pathways than does eWAT, clustering around the late-night early-morning transition. To explore how these pathways may be regulated, we reexamine a recent interscapular BAT cistrome dataset. Using in vitro-differentiated adipocyte (IVDA) transcription factors that are phase-aligned (≤4 h) with in vivo as input, motif enrichment analysis reveals 2 temporally distinct regulatory programs: an early E-box activator ARNT-family/bHLH-PAS program is enriched for transcriptional regulation, RNA metabolism, and signaling pathways, and a late nuclear receptor-associated program is enriched for energy metabolism, phospholipid biosynthesis, mitochondrial function, extracellular matrix (ECM) organization, and nuclear receptor signaling. Overall, we identify novel rhythmic transcripts and define cell-autonomous circadian programs in adipocytes whose timing is further sculpted by systemic cues in vivo. Because obesity is associated with adipocyte hypertrophy and hyperplasia, processes likely influenced by circadian regulation, these findings advance our understanding of clock-controlled adipocyte metabolism and its contribution to metabolic dysfunction.

Keywords: adipocytes; cell-autonomous; circadian; gene regulation; metabolism; transcription

DOI: https://doi.org/10.1177/07487304261480978

Plant Cell Rep. 2026 Sep 16. pii: 293. [Epub ahead of print]45(10):

Circadian- and light-regulated oscillatory expression of CSA in rice leaves is required for pollen fertility.

Renhe Dong, Jingbin Li, Duoxiang Wang, Linlin Sun, Jing Yu, Wanqi Liang, Jianxin Shi, Dabing Zhang.

KEY MESSAGE: The oscillatory expression of CSA in rice leaves is regulated by the circadian clock and red/far-red light signals, mediated through DOF5 and PIL11, and is required for normal pollen fertility. Photoperiod-sensitive male-sterile lines represent a pivotal innovation in the development of hybrid rice. However, the underlying mechanisms governing photoperiod-sensitive male reproductive development remain poorly understood. Our previous studies demonstrated that the carbon starved anther (csa) mutant exhibits male sterility under short-day (SD) conditions but partial fertility under long-day (LD) conditions. In this study, we report that CSA expression follows an oscillatory rhythm in rice leaves under both SD and LD conditions, a pattern regulated by both circadian clock and light signals. Tissue-specific RNA interference knockdown of CSA in leaves was associated with reduced pollen viability, suggesting that CSA expression in leaves contributes to normal male fertility. Promoter truncation assay results indicate that distinct regions of the CSA promoter contribute differentially to the regulation of CSA expression in leaves versus anthers, and that both the CSA expression level in anthers and the rhythmic expression pattern of CSA in leaves are associated with the restoration of male fertility. Using dual-luciferase, yeast one-hybrid, and electrophoretic mobility shift assays, we identified two proteins, PIL11 and DOF5, which directly bind to specific motifs (an E-box and T/AAAAG motif) within the CSA promoter truncation, thereby regulating its transcription. These findings elucidate novel mechanisms linking light sensing to the expression of circadian-controlled genes, thus connecting photoperiod with male reproductive development in rice.

Keywords: CSA (carbon starved anther); Circadian rhythm; DOF5; PIL-11; Photoperiod sensitive male sterility

DOI: https://doi.org/10.1007/s00299-026-03976-6

Cell Rep. 2026 Sep 17. pii: S2211-1247(26)01100-9. [Epub ahead of print]45(10): 118022

Anticipatory metabolic regulation drives the distinct and improved metabolic state of caloric restriction compared to Fasting-Refeeding cycles.

Nikkhil Velingkaar, Artem A Astafev, Archana Prabahar, Mart Andrew Maravillas, Evelina Trokhimenko, Josefa-Marie B Rom, Gena J Asi, Helen Piontkivska, Peng Jiang, Roman V Kondratov.

Interest in fasting-based diets to improve metabolic health is growing. Caloric restriction (CR) with one meal per day includes an extended fasting component that contributes to its metabolic and longevity benefits, yet the role of fasting within CR remains unclear. Here, we compare CR with a fasting-refeeding-fasting (FRF) regimen while controlling food intake and fasting duration. Changes in plasma insulin and free fatty acids, hepatic mTOR signaling and ketogenesis, metabolic rhythms, and food digestion kinetics suggest that gastric emptying serves as a primary metabolic trigger in acute fasting. In contrast, CR fasting responses are regulated, suggesting anticipatory mechanisms. CR enhances circadian rhythmicity and metabolic gene coordination, whereas FRF disrupts it. CR improves glucose and fatty acid metabolism, while fasting leads to glucose intolerance and liver fat accumulation. These findings reveal that CR engages clock-aligned, anticipatory metabolic control, while fasting-refeeding cycles rely on direct nutrient cues.

Keywords: CP: metabolism; aging; caloric restriction; circadian rhythms; fatty acid metabolism; gene expression; metabolism; transcription

DOI: https://doi.org/10.1016/j.celrep.2026.118022