The circadian clock plays a critical role in regulating various physiological processes, including gene expression, metabolic regulation, immune response, and the sleep-wake cycle in living organisms. Post-translational modifications (PTMs) are crucial regulatory mechanisms to maintain the precise oscillation of the circadian clock. By modulating the stability, activity, cell localization and protein-protein interactions of core clock proteins, PTMs enable these proteins to respond dynamically to environmental and intracellular changes, thereby sustaining the periodic oscillations of the circadian clock. Different types of PTMs exert their effects through distincting molecular mechanisms, collectively ensuring the proper function of the circadian system. This review systematically summarized several major types of PTMs, including phosphorylation, acetylation, ubiquitination, SUMOylation and oxidative modification, and overviewed their roles in regulating the core clock proteins and the associated pathways, with the goals of providing a theoretical foundation for the deeper understanding of clock mechanisms and the treatment of diseases associated with circadian disruption.
Protein Processing, Post-Translational/physiology* ; Circadian Rhythm/physiology* ; Humans ; Animals ; CLOCK Proteins/physiology* ; Circadian Clocks/physiology* ; Phosphorylation ; Acetylation ; Ubiquitination ; Sumoylation

The circadian rhythm regulates the 24-hour physiological and behavioral cycles through endogenous molecular clocks governed by core clock genes via the transcription-translation feedback loop (TTFL). In mammals, the suprachiasmatic nucleus (SCN) serves as the central pacemaker, coordinating the timing of physiological processes throughout the body by regulating clock genes such as CLOCK, BMAL1, PER, and CRY. The molecular clocks of peripheral tissues and cells are synchronized by the SCN through TTFLs to regulate metabolism, immunity, and energy homeostasis. Numerous studies indicate that circadian rhythm disruption is closely related to obesity, type 2 diabetes, metabolic syndrome and other diseases, and the mechanism involves the dysregulation of glucose and lipid metabolism, abnormal insulin signaling and low-grade inflammation. In recent years, small-molecule compounds targeting the core clock components such as CRY, REV-ERB, and ROR have been identified and shown potential to modulate metabolic diseases by stabilizing or inhibiting the activity of key clock proteins. This review summarizes the mechanisms and advances in these compounds, and explores the challenges and future directions for their clinical translation, providing insights for chronotherapy-based metabolic disease interventions.
Humans ; Metabolic Diseases/physiopathology* ; Animals ; Circadian Rhythm/physiology* ; Biological Clocks/drug effects* ; CLOCK Proteins/physiology* ; Circadian Clocks/physiology* ; Suprachiasmatic Nucleus/physiology*

The renin-angiotensin-aldosterone system (RAAS) is crucial for regulating blood pressure and maintaining fluid balance, while clock genes are essential for sustaining biological rhythms and regulating metabolism. There exists a complex interplay between RAAS and clock genes that may significantly contribute to the development of various cardiovascular and metabolic diseases. Although current literature has identified correlations between these two systems, the specific mechanisms of their interaction remain unclear. Moreover, the interaction patterns under different physiological and pathological conditions need further investigation. This review summarizes the synergistic roles of the RAAS and clock genes in cardiovascular diseases, explores their molecular mechanisms and pathophysiological connections, discusses the application of chronotherapy, and highlights potential future research directions, aiming to provide novel insights for the prevention and treatment of related diseases.
Humans ; Renin-Angiotensin System/genetics* ; Cardiovascular Diseases/genetics* ; CLOCK Proteins/physiology* ; Animals

Recently, male reproductive health has attracted extensive attention, with the adverse effects of circadian disruption on male fertility gradually gaining recognition. However, the mechanism by which circadian disruption leads to damage to male reproductive system remains unclear. In this review, we first summarized the dual regulatory roles of circadian clock genes on the male reproductive system: (1) circadian regulation of testosterone synthesis via the hypothalamic-pituitary-testicular (HPT) and hypothalamic-pituitary-adrenal (HPA) axes; (2) non-circadian regulation of spermatogenesis. Next, we further listed the possible mechanisms by which circadian disruption impairs male fertility, including interference with the oscillatory function of the reproductive system, i.e., synchronization of the HPT axis, crosstalk between the HPT axis and the HPA axis, as well as direct damage to germ cells by disturbing the non-oscillatory function of the reproductive system. Future research using spatiotemporal omics, epigenomic assays, and neural circuit mapping in studying the male reproductive system may provide new clues to systematically unravel the mechanisms by which circadian disruption affects male reproductive system through circadian clock genes.
Male ; Humans ; Animals ; Circadian Clocks/physiology* ; Hypothalamo-Hypophyseal System/physiology* ; Circadian Rhythm/genetics* ; Spermatogenesis/physiology* ; Pituitary-Adrenal System/physiology* ; Testis/physiology* ; Testosterone/biosynthesis* ; CLOCK Proteins ; Infertility, Male/physiopathology*

This paper aims to evaluate the pharmacodynamic effect and mechanism of Zhifuxin in the prevention and treatment of vascular dementia(VD), providing a theoretical basis for later development. Bilateral common carotid artery ligation in male Wistar rats was conducted to replicate the long-term hypoperfused VD model, and the drug was given to groups after one month. The rats were fed daily with nimodipine of 20 mg·kg~(-1), Zhifuxin of 50, 100, and 200 mg·kg~(-1), or the same volume of solvent for four weeks. 24 hours after the last dose, Morris water maze experiments were performed to detect the learning and memory abilities of rats. Hematoxylin-eosin(HE) staining was used to observe the pathological changes in the brain tissue of rats; the immunohistochemical method was used to detect the expression of muscarinic acetylcholine receptors M1 and M4 in rats and determine the content of acetyl choline(Ach), acetylcholin esterase(AchE), malondialdehyde(MDA), choline acetyl transferase(ChAT), and dimethyl arginine hydrolase 1(DDAH1) in the cerebral cortex of rats. Western blot was employed to detect protein expression of endothelial nitric oxide synthase(eNOS), caveolin-1, monoamine oxidase A(MAO-A), and monoamine oxidase B(MAO-B). RT-qPCR was utilized to detect mRNA expression of eNOS, caveolin-1, MAO-A, and MAO-B. The results showed that compared with the model group, the different doses of Zhifuxin were able to shorten the latency of VD rats in the water maze positioning navigation test, increase the number of crossing platforms in the space exploration test, and alleviate cone cell contracture in the hippocampus of VD rats. The expression of biochemical indicators related to the cholinergic system in the cerebral cortex: M1 and M4 receptors increased, as well as ChAT activity, and AchE activity significantly decreased. The protein and mRNA expression of indicators related to the eNOS/NO pathway: DDAH1 content, eNOS, and caveolin-1 increased, and that of indicators related to monoamine oxidase(MAO): MAO-A and MAO-B significantly decreased. The results show that Zhifuxin can improve cognition ability in long-term hypoperfused VD rats, and its mechanism of action may be related to its ability to modulate the cholinergic system and the eNOS/NO pathway and inhibit MAO expression.
Animals ; Dementia, Vascular/metabolism* ; Male ; Rats, Wistar ; Rats ; Drugs, Chinese Herbal/administration & dosage* ; Maze Learning/drug effects* ; Nitric Oxide Synthase Type III/genetics* ; Acetylcholinesterase/metabolism* ; Humans ; Choline O-Acetyltransferase/genetics* ; Disease Models, Animal

The circadian clock is a highly conserved timekeeping system in organisms, which maintains physiological homeostasis by precisely regulating periodic fluctuations in gene expression. Substantial clinical and experimental evidence has established a close association between circadian rhythm disruption and the development of various malignancies. Research has revealed characteristic alterations in the circadian gene expression profiles in tumor tissues, primarily manifested as a dysfunction of core clock components (particularly circadian locomotor output cycles kaput (CLOCK) and brain and muscle ARNT-like 1 (BMAL1)) and the widespread dysregulation of their downstream target genes. Notably, CLOCK demonstrates non-canonical oncogenic functions, including epigenetic regulation via histone acetyltransferase activity and the circadian-independent modulation of cancer pathways. This review systematically elaborates on the oncogenic mechanisms mediated by CLOCK/BMAL1, encompassing multidimensional effects such as cell cycle control, DNA damage response, metabolic reprogramming, and tumor microenvironment (TME) remodeling. Regarding the therapeutic strategies, we focus on cutting-edge approaches such as chrononutritional interventions, chronopharmacological modulation, and treatment regimen optimization, along with a discussion of future perspectives. The research breakthroughs highlighted in this work not only deepen our understanding of the crucial role of circadian regulation in cancer biology but also provide novel insights for the development of chronotherapeutic oncology, particularly through targeting the non-canonical functions of circadian proteins to develop innovative anti-cancer strategies.
Humans ; ARNTL Transcription Factors/physiology* ; Neoplasms/therapy* ; CLOCK Proteins/physiology* ; Circadian Clocks/genetics* ; Animals ; Circadian Rhythm/genetics* ; Tumor Microenvironment ; Epigenesis, Genetic ; Gene Expression Regulation, Neoplastic

High mobility group box 1 (HMGB1), when released extracellularly, plays a pivotal role in the development of spinal cord synapses and exacerbates autoimmune diseases within the central nervous system. In experimental autoimmune encephalomyelitis (EAE), a condition that models multiple sclerosis, the levels of extracellular HMGB1 and interleukin-33 (IL-33) have been found to be inversely correlated. However, the mechanism by which IL-33 deficiency enhances HMGB1 release during EAE remains elusive. Our study elucidates a potential signaling pathway whereby the absence of IL-33 leads to increased binding of P300/CBP-associated factor with HMGB1 in the nuclei of astrocytes, upregulating HMGB1 acetylation and promoting its release from astrocyte nuclei in the spinal cord of EAE mice. Conversely, the addition of IL-33 counteracts the TNF-α-induced increase in HMGB1 and acetylated HMGB1 levels in primary astrocytes. These findings underscore the potential of IL-33-associated signaling pathways as a therapeutic target for EAE treatment.
Animals ; Encephalomyelitis, Autoimmune, Experimental/metabolism* ; Astrocytes/metabolism* ; Interleukin-33/metabolism* ; HMGB1 Protein/metabolism* ; Acetylation ; Mice, Knockout ; Mice, Inbred C57BL ; p300-CBP Transcription Factors/metabolism* ; Mice ; Spinal Cord/metabolism* ; Cells, Cultured ; Female ; Signal Transduction

Sepsis is a life-threatening organ dysfunction caused by the host's dysregulated response to infection, with a complex pathogenesis and high mortality rate. Currently, there are no clear and effective treatment drugs available. Epigenetic modification serves as a major mechanism regulating gene expression under pathological and physiological conditions, and it has been shown to play a critical role in regulating the occurrence and development of sepsis. Histone acetylation modification, as a sophisticated epigenetic modification mechanism, plays a crucial regulatory role in many aspects of life. It can jointly regulate the acetylation status of histones through histone acetyltransferase (HAT) and histone deacetylase (HDAC), thereby changing DNA expression and dynamically regulating sepsis related gene expression at the epigenetic level. Previous studies have shown that histone acetylation can participate in the progression of sepsis by regulating inflammatory mediators, nuclear factor-ΚB (NF-ΚB) signaling pathway, autophagy, efferocytosis, ferroptosis, pyroptosis. These mechanisms are promising targets for novel sepsis treatments. In addition, with the deepening of research, it has been found that various selective/non selective histone deacetylase inhibitors (HDACI) can regulate histone acetylation status by acting on different HDAC targets, which has been shown to alleviate organ damage caused by sepsis and improve prognosis in septic animal models. This article further summarizes the role and potential applications of histone acetylation in sepsis, providing new ideas for the treatment of sepsis.
Sepsis/metabolism* ; Acetylation ; Humans ; Histones/metabolism* ; Histone Acetyltransferases/metabolism* ; Histone Deacetylase Inhibitors ; Epigenesis, Genetic ; Histone Deacetylases/metabolism* ; Signal Transduction ; NF-kappa B/metabolism* ; Animals

Existing studies have underscored the pivotal role of N-acetyltransferase 10 (NAT10) in various cancers. However, the outcomes of protein-protein interactions between NAT10 and its protein partners in head and neck squamous cell carcinoma (HNSCC) remain unexplored. In this study, we identified a significant upregulation of RNA-binding protein with serine-rich domain 1 (RNPS1) in HNSCC, where RNPS1 inhibits the ubiquitination degradation of NAT10 by E3 ubiquitin ligase, zinc finger SWIM domain-containing protein 6 (ZSWIM6), through direct protein interaction, thereby promoting high NAT10 expression in HNSCC. This upregulated NAT10 stability mediates the enhancement of specific tRNA ac⁴C modifications, subsequently boosting the translation process of genes involved in pathways such as IL-6 signaling, IL-8 signaling, and PTEN signaling that play roles in regulating HNSCC malignant progression, ultimately influencing the survival and prognosis of HNSCC patients. Additionally, we pioneered the development of TRMC-seq, leading to the discovery of novel tRNA-ac⁴C modification sites, thereby providing a potent sequencing tool for tRNA-ac⁴C research. Our findings expand the repertoire of tRNA ac⁴C modifications and identify a role of tRNA ac⁴C in the regulation of mRNA translation in HNSCC.
Humans ; DNA-Binding Proteins ; Head and Neck Neoplasms/genetics* ; N-Terminal Acetyltransferases ; RNA, Transfer ; Serine ; Signal Transduction ; Squamous Cell Carcinoma of Head and Neck

This study aims to investigate the mechanism of berberine in regulating the metabolism network via clock-controlled genes represented by brain and muscle arnt-like 1(BMAL1) to ameliorate insulin resistance(IR) of hepatocytes in vitro. The HepG2 cell model of dexamethasone-induced IR(IR-HepG2) was established and treated with 5, 10, and 20 μmol·L~(-1) berberine, respectively, for 24 h. The glucose oxidase method and cell counting kit-8(CCK-8) assay were employed to measure extracellular glucose concentration and cell viability, respectively. Periodic acid-Schiff(PAS) staining and lipid fluorescence method were used to detect glycogen and lipids. The immunofluorescence(IF) assay was employed to detect the nuclear localization of BMAL1 and circadian locomotor output cycles kaput(CLOCK) in IR-HepG2 cells. Western blot was employed to determine the protein levels of BMAL1, CLOCK, period circadian clock 2(PER2), cryptochrome circadian regulator 1(CRY1), Rev-Erbα, carbohydrate response element-binding protein(ChREBP), peroxisome proliferator-activated receptors alpha and gamma(PPARα/γ), sterol regulatory element-binding protein 1C(SREBP-1C), mammalian target of rapamycin(mTOR), protein kinase B(Akt), glycogen synthase kinase-3β(GSK3β), acetyl coenzyme A carboxylase 1(ACC1), fatty acid synthase(FASN), carnitine palmitoyltransferase 1α(CPT1α), nicotinamide phosphoribosyltransferase(NAMPT), silent information regulator 1(SIRT1), adiponectin(ADPN), insulin receptor substrate 2(IRS2), and phosphatidylinositol 3-kinase regulatory subunit p85(PI3Kp85). In addition, the levels of phosphorylated adenosine monophosphate-activated protein kinase alpha(AMPKα), Akt, GSK3β, BMAL1, and mTOR were determined. Furthermore, 20 μmol·L~(-1) CLK8 was added to measure the glucose consumption as well as the protein levels of ChREBP, PPARα, and mTOR in IR-HepG2 cells. The results showed that berberine increased the glucose consumption, lowered the lipid levels, increased the expression and nuclear localization of BMAL1 and CLOCK, and up-regulated the level of BMAL1 in IR-HepG2 cells. Furthermore, berberine up-regulated the levels of ADPN, IRS2, PI3Kp85, p-Akt(Ser473)/Akt, p-mTOR(Ser2448)/mTOR, PPARα, and CPT1α, and down-regulated the levels of p-GSK3β(Ser9)/GSK3β, ChREBP, SREBP-1C, ACC1, and FASN. The addition of CLK8 reduced glucose consumption in IR-HepG2 cells, up-regulated the ChREBP level, and down-regulated PPARα and mTOR levels by inhibiting the BMAL1 and CLOCK interaction. In summary, berberine regulated glucose and lipid metabolism via clock-controlled genes with BMAL1 at the core to ameliorate IR of hepatocytes.
Humans ; Hepatocytes/drug effects* ; Lipid Metabolism/drug effects* ; Glucose/metabolism* ; Berberine/pharmacology* ; Insulin Resistance ; Hep G2 Cells ; CLOCK Proteins/genetics* ; ARNTL Transcription Factors/genetics*