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

This study aims to elucidate the role and mechanism of clematichinenoside AR(CAR) in protecting bone marrow mesenchymal stem cells(BMSCs) from hypoxia-induced apoptosis. BMSCs were isolated by the bone fragment method and identified by flow cytometry. Cells were cultured under normal conditions(37℃, 5% CO_2) and hypoxic conditions(37℃, 90% N_2, 5% CO_2) and treated with CAR. The BMSCs were classified into eight groups: control(normal conditions), CAR(normal conditions + CAR), hypoxia 24 h, hypoxia 24 h + CAR, hypoxia 48 h, hypoxia 48 h + CAR, hypoxia 72 h, and hypoxia 72 h + CAR. The cell counting kit-8(CCK-8) assay and terminal-deoxynucleoitidyl transferase mediated nick end labeling(TUNEL) were employed to measure cell proliferation and apoptosis, respectively. The number of mitochondria and mitochondrial membrane potential were measured by MitoTracker®Red CM-H2XRo staining and JC-1 staining, respectively. The level of reactive oxygen species(ROS) was measured with the DCFH-DA fluorescence probe. The protein levels of B-cell lymphoma-2 associated X protein(BAX), caspase-3, and optic atrophy 1(OPA1) were determined by Western blot. The results demonstrated that CAR significantly increased cell proliferation. Compared with the control group, the hypoxia groups showed increased apoptosis rates, reduced mitochondria, elevated ROS levels, decreased mitochondrial membrane potential, upregulated expression of BAX and caspase-3, and downregulated expression of OPA1. In comparison to the corresponding hypoxia groups, CAR intervention significantly decreased the apoptosis rate, increased mitochondria, reduced ROS levels, elevated mitochondrial membrane potential, downregulated the expression of BAX and caspase-3, and upregulated the expression of OPA1. Therefore, it can be concluded that CAR may exert an anti-apoptotic effect on BMSCs under hypoxic conditions by regulating OPA1 to maintain mitochondrial homeostasis.
Mesenchymal Stem Cells/metabolism* ; Apoptosis/drug effects* ; Mitochondria/metabolism* ; Animals ; Rats ; Cell Hypoxia/drug effects* ; Homeostasis/drug effects* ; Reactive Oxygen Species/metabolism* ; Rats, Sprague-Dawley ; Membrane Potential, Mitochondrial/drug effects* ; Saponins/pharmacology* ; Caspase 3/genetics* ; Male ; bcl-2-Associated X Protein/genetics* ; Bone Marrow Cells/metabolism* ; Cell Proliferation/drug effects* ; Protective Agents/pharmacology* ; Cells, Cultured

The interaction between m⁶A-methylated RNA and chromatin modification remains largely unknown. We found that targeted inhibition of bromodomain-containing protein 4 (BRD4) by siRNA or its inhibitor (JQ1) significantly decreases mRNA m⁶A levels and suppresses the malignancy of breast cancer (BC) cells via increased expression of demethylase AlkB homolog 5 (ALKBH5). Mechanistically, inhibition of BRD4 increases the mRNA stability of ALKBH5 via enhanced binding between its 3' untranslated regions (3'UTRs) with RNA-binding protein RALY. Further, BRD4 serves as a scaffold for ubiquitin enzymes tripartite motif containing-21 (TRIM21) and ALKBH5, resulting in the ubiquitination and degradation of ALKBH5 protein. JQ1-increased ALKBH5 then demethylates mRNA of extra spindle pole bodies like 1 (ESPL1) and reduces binding between ESPL1 mRNA and m⁶A reader insulin like growth factor 2 mRNA binding protein 3 (IGF2BP3), leading to decay of ESPL1 mRNA. Animal and clinical studies confirm a critical role of BRD4/ALKBH5/ESPL1 pathway in BC progression. Further, our study sheds light on the crosstalks between histone modification and RNA methylation.

Objective To explore the comparative application of phase and diaphragmatic navigation in three-dimensional magnetic resonance cholangiopancreatography(3D-MRCP)thin-layer scanning in elderly patients.Methods A total of 180 elderly patients were scanned by phase and diaphragmatic navigation via Siemens Aera1.5T superconducting MR scanner.The acquired images were reconstructed by 3D reconstruction.The anatomical structure,image quality and disease diagnosis were compared between the phase and diaphragmatic navigation groups.Results In liver of anatomy,the liver of primary bile duct,the superior,middle and inferior extrahepatic bile duct and the gallbladder could be well displayed,and the difference was not statistically significant between the two groups(P＞0.05).The display of pancreatic duct and the liver of secondary bile duct of diaphragmatic navigation was significantly better than those of phase navigation(P＜0.05).In terms of image quality,the excellent rate of diaphragmatic navigation was significantly higher than that of phase navigation,and the difference was statistically significant(P＜0.05).There were no statistically significant differences in the detection rate of pancreatobiliary system diseases,the diagnostic rate of cholelithiasis,common bile duct stones,common bile duct dilatation and pancreatic duct dilatation between the two groups(P＞0.05).Conclusion Diaphragmatic navigation is signifi-cantly better than phase navigation in the display of the anatomical structure of the pancreatic duct,the liver of secondary bile duct,and the excellent rate of image quality.Diaphragmatic navigation is more suitable for thin-layer 3D-MRCP scanning in elderly patients.

BACKGROUND:A large number of studies have investigated the effects of whole body vibration training at different frequencies on muscle strength,but less is reported on the differences in the efficacy of vibration training at different frequencies on patellar tendinopathy. OBJECTIVE:To explore the effect of eccentric training of quadriceps combined with different frequency of whole body vibration training on patellar tendinopathy. METHODS:From April to June 2022,48 patients with patellar tendinopathy were recruited from Wuhan Sports University and randomly divided into eccentric training group(n=12),30 Hz group(n=12),40 Hz group(n=12),and 50 Hz group(n=12).The eccentric training group only completed eccentric training of the quadriceps.The 30 Hz,40 Hz and 50 Hz groups performed the whole body vibration training with the amplitude of 2 mm and frequencies of 30 Hz,40 Hz and 50 Hz respectively on the basis of the eccentric training of the quadriceps.The intervention lasted for 8 weeks,three times a week.Before and after the intervention,the patients'surface electromyography signals of the quadriceps,kinematics and dynamics data of knee joint at the time of landing in deep jump and the time of peak vertical ground reaction,Visual Analogue Scale score,Victorian Institute of Sports Assessment-Patellar score were evaluated. RESULTS AND CONCLUSION:After 8 weeks of intervention,compared with the eccentric training group,the median frequency of the lateral and medial femoris muscles were significantly higher in the 40 Hz and 50 Hz groups(P＜0.05).At the time of landing,the knee joint flexion angle and external rotation moment in the 40 Hz and 50 Hz groups were significantly lower than those in the eccentric training group(P＜0.05),while the knee joint flexion angle in the 50 Hz group was significantly lower than that in the 30 Hz group(P＜0.05).At the peak moment of vertical ground reaction,the knee extension torque in the 40 Hz group was significantly lower than that in the eccectric training group(P＜0.05);the knee flexion angle and knee extension torque in the 50 Hz group were significantly lower than those in the eccentric training group(P＜0.05).The Visual Analogue Scale scores in the 50 Hz and 40 Hz groups were significantly lower than those in the eccentric training group(P＜0.05).The Victorian Institute of Sports Assessment-Patellar score in the 50 Hz group was significantly higher than that in the eccentric training group and 30 Hz group(P＜0.05).To conclude,eccentric training of the quadriceps combined with 50 Hz whole body vibration training can significantly improve quadriceps'strength,endurance and activation rate of the vastus lateralis muscle,reduce the pain of knee joint,and improve the function of the knee joint in patients with patellar tendinopathy.

The main protease (M^pro) of SARS-CoV-2 is an attractive target in anti-COVID-19 therapy for its high conservation and major role in the virus life cycle. The covalent M^pro inhibitor nirmatrelvir (in combination with ritonavir, a pharmacokinetic enhancer) and the non-covalent inhibitor ensitrelvir have shown efficacy in clinical trials and have been approved for therapeutic use. Effective antiviral drugs are needed to fight the pandemic, while non-covalent M^pro inhibitors could be promising alternatives due to their high selectivity and favorable druggability. Numerous non-covalent M^pro inhibitors with desirable properties have been developed based on available crystal structures of M^pro. In this article, we describe medicinal chemistry strategies applied for the discovery and optimization of non-covalent M^pro inhibitors, followed by a general overview and critical analysis of the available information. Prospective viewpoints and insights into current strategies for the development of non-covalent M^pro inhibitors are also discussed.

AIM To explore the clinical effects of Bushen Huoxue Ointment Formula on patients with ankylosing spondylitis of Kidney Deficiency and Blood Stasis Pattern.METHODS One hundred and sixty-seven patients were randomly assigned into control group(55 cases)for 2-year intervention of conventional treatment,exposure group(54 cases)for 2-year intervention of both Bushen Huoxue Decoction and conventional treatment,and high exposure group(58 cases)for 2-year intervention of Bushen Huoxue Ointment Formula,Bushen Huoxue Decoction and conventional treatment.The changes in clinical effects,BASDAI score,ASDAS-CRP,BASFI score,spinal pain score,PGA score,BASMI score,ASQoL score,SPARCC score,Kidney Deficiency and Blood Stasis Pattern score,ESR,CRP,IL-6,TNF-α,IL-17,IL-23,IL-35,NLR,PLR and safety indices were detected.RESULTS The high exposure group demonstrated more ASAS40,ASASAS5/6,BASDAI50 cases than the exposure group and the control group(P<0.05).After the treatment,the high exposure group displayed lower BASDAI score,ASDAS-CRP,BASFI score,spinal pain score,PGA score,BASMI score,SPARCC score,ASQoL score,Kidney Deficiency and Blood Stasis Pattern score,ESR,CRP,IL-6,TNF-α,IL-17,IL-23 than the other two groups(P<0.05),and higher IL-35(P<0.05).After adjusting confounding factors by logistic regression analysis,Bushen Huoxue Decoction and Bushen Huoxue Ointment Formula reduced BASDAI score,ASDAS-CRP(P<0.05),and enhanced clinical effects(P<0.05).No serious adverse reactions were found in the three groups.CONCLUSION For the patients with ankylosing spondylitis of Kidney Deficiency and Blood Stasis Pattern,Bushen Huoxue Ointment Formula can safely and effectively inhibit inflammation,reduce disease activity,alleviate bone marrow edema,improve clinical symptoms,and enhance joint functions and life quality.

ObjectiveTo investigate the contamination status of Staphylococcus aureus in food and the presence of enterotoxin genes in Jiading District， Shanghai， and to provide a basis for the prevention and treatment of foodborne Staphylococcus aureus disease. MethodsFrom 2021 to 2023， 15 types of food were sampled for S. aureus testing， and the presence of five enterotoxin genes， including sea⁃see， was tested in the strains. ResultsOut of 705 food samples， 88 （12.48%） were positive for S. aureus. S. aureus was detected in 12 of the 15 food types， with the three food types with the highest positive rates being cold noodles （45.00%）， raw poultry （26.25%）， and vegetable salads （20.00%）. The enterotoxin gene carriage rate was 32.95% in food strains. The carriage rates for sea， seb， and sec were 7.95%， 12.50%， and 14.77%， respectively. Neither sed nor see was detected. The detection rate of strains carrying two types of enterotoxin genes was 2.27%. The enterotoxin carriage rates in strains from vegetables， beverages， and raw meat were 57.14%， 40.00%， and 30.00%， respectively. ConclusionThe S. aureus detection rate in food in Jiading District is much higher than the national average. The enterotoxin gene carriage rates are high， with food strains carrying sea， seb， and sec， with sec being the most prevalent. There is a need to enhance monitoring of S. aureus and enterotoxins， especially in high-risk foods such as noodles， vegetables， and non-packaged beverages.

The Wnt signaling pathway includes both classical and non classical pathways,Wnt5a-Frizzled-2 pathway participates in the Wnt/Ca2+signaling pathway in the non-classical pathway,which is activated by the Wnt-related protein Wnt5a and its ligand Frizzled-2.It can regulate some key sites in cells to affect cell signal transduction,and is closely related to cell growth process.Activation of Wnt5a-Fizzled-2 pathway occurs in some tissues with abundant blood supply,such as heart and brain tissues,during ischemia-reperfusion.Activation of the Wnt5a-Frizzled-2 pathway causes these intracellular calcium overload,ultimately promoting apoptosis.This article reviews the abnormal activation of Wnt5a-Frizzled-2 signaling pathway in ischemia-reperfusion injury diseases and the induced calcium overload leading to apoptosis,in order to provide reference for the study of physiological mechanisms of ischemia-reperfusion injury.

ObjectiveTo investigate the prevalence of Staphylococcus aureus in patients with diarrhea, and to analyze the genes carriage of enterotoxin in the strains of these patients in Jiading District, Shanghai. MethodsFrom 2021 to 2023, anal swabs of diarrhea outpatients from one sentinel hospital and nine community health service centers in different townships in Jiading District, Shanghai, were tested for Staphylococcus aureus, from which five enterotoxin virulence genes such as SEA, SEB, SEC, SED, and SEE were tested simultaneously. ResultsA total of 1 080 anal swabs were collected, 81 of which were tested positive for S. aureus, with a detection rate of 7.50%, and the detection rate of S. aureus was similar in patients with diarrhea from 2021‒2023. There was no statistically significant difference in detection rates between males and females (χ²=0.821, P=0.365). S. aureus detection rate was highest in infants and young children with diarrhea (29.51%), followed by 14.06% in the people aged between 4‒<31 years, and 2.99% in those aged ≥31 years. Significant differences were observed in the detection rate of S. aureus in the diarrhoeal patients from different townships of Jiading District(χ²=66.134,P<0.05). The carriage rates of the 5 enterotoxin genes, namely SEA, SEB, SEC, SED, SEE, were 13.58%, 14.81%, 11.11%, 7.41%, and 0, respectively. ConclusionThe prevalence of S. aureus among the patients with diarrhea in Jiading District is relatively stable but with distinct geographical patterns. Children and adolescents are high-risk groups. SEB were the dominant gene, followed by SEA.