OBJECTIVE: Gastric cancer (GC) is one of the most common malignancies seen in clinic and requires novel treatment options. Morin is a natural flavonoid extracted from the flower stalk of a highly valuable medicinal plant Prunella vulgaris L., which exhibits an anti-cancer effect in multiple types of tumors. However, the therapeutic effect and underlying mechanism of morin in treating GC remains elusive. The study aims to explore the therapeutic effect and underlying molecular mechanisms of morin in GC. METHODS: For in vitro experiments, the proliferation inhibition of morin was measured by cell counting kit-8 assay and colony formation assay in human GC cell line MKN45, human gastric adenocarcinoma cell line AGS, and human gastric epithelial cell line GES-1; for apoptosis analysis, microscopic photography, Western blotting, ubiquitination analysis, quantitative polymerase chain reaction analysis, flow cytometry, and RNA interference technology were employed. For in vivo studies, immunohistochemistry, biomedical analysis, and Western blotting were used to assess the efficacy and safety of morin in a xenograft mouse model of GC. RESULTS: Morin significantly inhibited the proliferation of GC cells MKN45 and AGS in a dose- and time-dependent manner, but did not inhibit human gastric epithelial cells GES-1. Only the caspase inhibitor Z-VAD-FMK was able to significantly reverse the inhibition of proliferation by morin in both GC cells, suggesting that apoptosis was the main type of cell death during the treatment. Morin induced intrinsic apoptosis in a dose-dependent manner in GC cells, which mainly relied on B cell leukemia/lymphoma 2 (BCL-2) associated agonist of cell death (BAD) but not phorbol-12-myristate-13-acetate-induced protein 1. The upregulation of BAD by morin was due to blocking the ubiquitination degradation of BAD, rather than the transcription regulation and the phosphorylation of BAD. Furthermore, the combination of morin and BCL-2 inhibitor navitoclax (also known as ABT-737) produced a synergistic inhibitory effect in GC cells through amplifying apoptotic signals. In addition, morin treatment significantly suppressed the growth of GC in vivo by upregulating BAD and the subsequent activation of its downstream apoptosis pathway. CONCLUSION Morin suppressed GC by inducing apoptosis, which was mainly due to blocking the ubiquitination-based degradation of the pro-apoptotic protein BAD. The combination of morin and the BCL-2 inhibitor ABT-737 synergistically amplified apoptotic signals in GC cells, which may overcome the drug resistance of the BCL-2 inhibitor. These findings indicated that morin was a potent and promising agent for GC treatment. Please cite this article as: Wang Y, Sun XY, Ma FQ, Ren MM, Zhao RH, Qin MM, Zhu XH, Xu Y, Cao ND, Chen YY, Dong TG, Pan YF, Zhao AG. Morin inhibits ubiquitination degradation of BCL-2 associated agonist of cell death and synergizes with BCL-2 inhibitor in gastric cancer cells. J Integr Med. 2025; 23(3): 320-332.
Humans ; Flavonoids/therapeutic use* ; Stomach Neoplasms/pathology* ; Animals ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Cell Line, Tumor ; Apoptosis/drug effects* ; Cell Proliferation/drug effects* ; Ubiquitination/drug effects* ; Mice ; Drug Synergism ; Mice, Inbred BALB C ; Mice, Nude ; Xenograft Model Antitumor Assays ; Flavones

Ribosomally synthesized and post-translationally modified peptides (RiPPs) constitute a vast and diverse family of bioactive peptides. These peptides, synthesized by ribosomes and subsequently modified by various tailoring enzymes, possess a wide chemical space. Among these modifications, radical S-adenosylmethionine (rSAM) enzymes employ unique radical chemistry to introduce a variety of novel peptide structures, which are crucial for their activity. This review examines the major types of modifications in RiPPs catalyzed by rSAM enzymes, incorporating recent advancements in protein structure analysis techniques and computational methods. Additionally, it elucidates the diverse catalytic mechanisms and substrate selectivity of these enzymes through an analysis of the latest crystal structures.
Protein Processing, Post-Translational ; S-Adenosylmethionine/chemistry* ; Ribosomes/metabolism* ; Peptides/metabolism* ; Biological Products/metabolism* ; Humans

Zishen Huoxue decoction (ZSHX) enhances cardiomyocyte viability following hypoxic stress; however, its upstream therapeutic targets remain unclear. Network pharmacology and RNA sequencing analyses revealed that ZSHX target genes were closely associated with mitophagy and apoptosis in the mitochondrial pathway. In vitro, ZSHX inhibited pathological mitochondrial fission following hypoxic stress, regulated FUN14 domain-containing protein 1 (FUNDC1)-related mitophagy, and increased the levels of mitophagy lysosomes and microtubule-associated protein 1 light chain 3 beta II (LC3II)/translocase of outer mitochondrial membrane 20 (TOM20) expression while inhibiting the over-activated mitochondrial unfolded protein response. Additionally, ZSHX regulated the stability of beta-tubulin through Sirtuin 5 (SIRT5) and could modulate FUNDC1-related synergistic mechanisms of mitophagy and unfolded protein response in the mitochondria (UPR^mt) via the SIRT5 and -β-tubulin axis. This targeting pathway may be crucial for cardiomyocytes to resist hypoxia. Collectively, these findings suggest that ZSHX can protect against cardiomyocyte injury via the SIRT5-β-tubulin axis, which may be associated with the synergistic protective mechanism of SIRT5-β-tubulin axis-related mitophagy and UPR^mt on cardiomyocytes.
Mitophagy/drug effects* ; Tubulin/genetics* ; Animals ; Myocytes, Cardiac/metabolism* ; Drugs, Chinese Herbal/pharmacology* ; Sirtuins/genetics* ; Unfolded Protein Response/drug effects* ; Myocardial Ischemia/genetics* ; Rats ; Humans ; Rats, Sprague-Dawley ; Apoptosis/drug effects* ; Male

Objective To explore the mechanism of ubiquitin specific peptidase 21 (USP21) increasing the stability of forkhead box protein M1 (FOXM1) and promoting M2 polarization of macrophages in endometriosis (EM). Methods Eutopic endometrial stromal cells (EESC) collected from patients and normal endometrial stromal cells (NESC) from routine health examiners were cultured in vitro, and the expression levels of USP21 and FOXM1 were detected using RT-qPCR and Western blot. EESCs were co-cultured with macrophages. M1 polarization markers of interleukin 6 (IL-6) and CXC chemokine ligand 10 (CXCL10) and M2 polarization markers of CD206 and fibronectin 1 (FN1) were tested using RT-qPCR. M2 marker CD206 was further detected by flow cytometry. IL-6, tumor necrosis factor-alpha (TNF-α), IL-10, and transforming growth factor-beta (TGF-β) levels in cell supernatant were detected by ELISA. Co-immunoprecipitation was used to assess the interaction between USP21 and FOXM1, and the ubiquitination level of FOXM1. FOXM1 protein stability was detected through cycloheximide (CHX) assay. Results USP21 and FOXM1 expression levels in the EESC group were significantly increased compared with those in the NESC group; compared with the NESC + M0 group, the EESC + M0 group showed no significant difference in the expression of M1 polarization markers (IL-6 and CXCL10), but increased expression of M2 polarization markers (CD206 and FN1), along with notably increased number of M2 macrophages; there was no significant difference in IL-6 and TNF-α levels, but increased levels of IL-10 and TGF-β in the cell supernatant. The above findings indicated that the deubiquitinase USP21 was highly expressed in EM, promoting M2 polarization of macrophages. Knocking down USP21 or FOXM1 can inhibit M2 polarization of EM macrophages. USP21 interacted with FOXM1 in EESC, leading to a decrease in FOXM1 ubiquitination level and an increase in FOXM1 protein stability. Overexpression of FOXM1 reversed the inhibitory effect of knocking down USP21 on M2 polarization of EM macrophages. Conclusion The deubiquitinase USP21 interacts with FOXM1 to increase the stability of FOXM1 and promote M2 polarization of EM macrophages.
Humans ; Forkhead Box Protein M1/genetics* ; Female ; Macrophages/cytology* ; Endometriosis/genetics* ; Ubiquitin Thiolesterase/genetics* ; Cells, Cultured ; Endometrium/metabolism* ; Ubiquitination ; Adult ; Interleukin-10/metabolism* ; Interleukin-6/metabolism* ; Protein Stability ; Stromal Cells/metabolism*

Ubiquitination is one of the most widely distributed, structurally diverse, and functionally important post-translational modifications for proteins in eukaryotic cells. At present, the methods for detecting ubiquitination signals mainly include immunological detection based on specific antibodies, mass spectrometry, and detection based on ubiquitin-binding domain (UBD), which together constitute a tool library for studying ubiquitination signals. Our team has previously developed a high-throughput detection technology based on an artificial tandem hybrid ubiquitin-binding domain (ThUBD), which achieves universal and highly sensitive detection of all polyubiquitin chain modification signals. This study aims to evaluate the specificity and range of ThUBD-coated multi-well plates in detecting ubiquitination signals and verify the reliability and practicality of these plates in practical applications. We then used this technology to analyze the complex and diverse ubiquitination signals in different biological samples such as cells, tissues, and urine and detect ubiquitination signals in different mass ranges. The results showed that this technology had strong universality and good specificity, and it can accurately identify ubiquitinated proteins from non-ubiquitinated proteins and achieve accurate quantification. This study provides a sensitive, specific, rapid, and efficient analytical technology for the high-throughput detection of ubiquitination signals.
Ubiquitination ; High-Throughput Screening Assays ; Protein Domains ; Signal Transduction ; Ubiquitin/chemistry*

Chronic cerebral hypoperfusion leads to white matter injury (WMI), which plays a significant role in contributing to vascular cognitive impairment. While 13-docosenamide is a type of fatty acid amide, it remains unclear whether it has therapeutic effects on chronic cerebral hypoperfusion. In this study, we conducted bilateral common carotid artery stenosis (BCAS) surgery to simulate chronic cerebral hypoperfusion-induced WMI and cognitive impairment. Our findings showed that 13-docosenamide alleviates WMI and cognitive impairment in BCAS mice. Mechanistically, 13-docosenamide specifically binds to cannabinoid receptor 1 (CNR1) in oligodendrocyte precursor cells (OPCs). This interaction results in an upregulation of ubiquitin-specific peptidase 33 (USP33)-mediated CNR1 deubiquitination, subsequently increasing CNR1 protein expression, activating the phosphorylation of the AKT/mTOR pathway, and promoting the differentiation of OPCs. In conclusion, our study suggests that 13-docosenamide can ameliorate chronic cerebral hypoperfusion-induced WMI and cognitive impairment by enhancing OPC differentiation and could serve as a potential therapeutic drug.
Animals ; Oligodendrocyte Precursor Cells/metabolism* ; Mice ; Cell Differentiation/drug effects* ; Male ; Receptor, Cannabinoid, CB1/metabolism* ; Mice, Inbred C57BL ; Ubiquitin Thiolesterase/metabolism* ; Ubiquitination/drug effects* ; Carotid Stenosis/complications* ; Cognitive Dysfunction/drug therapy*

Epilepsy is a chronic neurological disorder affecting ~65 million individuals worldwide. Abnormal synaptic plasticity is one of the most important pathological features of this condition. We investigated how ubiquitin-specific peptidase 47 (USP47) influences synaptic plasticity and its link to epilepsy. We found that USP47 enhanced excitatory postsynaptic transmission and increased the density of total dendritic spines and the proportion of mature dendritic spines. Furthermore, USP47 inhibited the degradation of the ubiquitinated α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunit glutamate receptor 1 (GluR1), which is associated with synaptic plasticity. In addition, elevated levels of USP47 were found in epileptic mice, and USP47 knockdown reduced the frequency and duration of seizure-like events and alleviated epileptic seizures. To summarize, we present a new mechanism whereby USP47 regulates excitatory postsynaptic plasticity through the inhibition of ubiquitinated GluR1 degradation. Modulating USP47 may offer a potential approach for controlling seizures and modifying disease progression in future therapeutic strategies.
Animals ; Receptors, AMPA/metabolism* ; Neuronal Plasticity/physiology* ; Seizures/physiopathology* ; Disease Models, Animal ; Mice, Inbred C57BL ; Mice ; Ubiquitin Thiolesterase/genetics* ; Male ; Excitatory Postsynaptic Potentials/physiology* ; Ubiquitination ; Dendritic Spines/metabolism* ; Hippocampus/metabolism*

Neuropathic pain is frequently comorbidity with cognitive deficits. Neuralized1 (Neurl1)-mediated ubiquitination of CPEB3 in the hippocampus is critical in learning and memory. However, the role of Neurl1 in the cognitive impairment in neuropathic pain remains elusive. Herein, we found that lumbar 5 spinal nerve ligation (SNL) in male rat-induced neuropathic pain was followed by learning and memory deficits and LTP impairment in the hippocampus. The Neurl1 expression in the hippocampal CA1 was decreased after SNL. And this decrease paralleled the reduction of ubiquitinated-CPEB3 level and reduced production of GluA1 and GluA2. Overexpression of Neurl1 in the CA1 rescued cognitive deficits and LTP impairment, and reversed the reduction of ubiquitinated-CPEB3 level and the decrease of GluA1 and GluA2 production following SNL. Specific knockdown of Neurl1 or CPEB3 in bilateral hippocampal CA1 in naïve rats resulted in cognitive deficits and impairment of synaptic plasticity. The rescued cognitive function and synaptic plasticity by the treatment of overexpression of Neurl1 before SNL were counteracted by the knockdown of CPEB3 in the CA1. Collectively, the above results suggest that the downregulation of Neurl1 through reducing CPEB3 ubiquitination and, in turn, repressing GluA1 and GluA2 production and mediating synaptic plasticity impairment in hippocampal CA1 leads to the genesis of cognitive deficits in neuropathic pain.
Animals ; Male ; Neuralgia/metabolism* ; Rats ; Down-Regulation/physiology* ; Ubiquitination/physiology* ; Neuronal Plasticity/physiology* ; Rats, Sprague-Dawley ; CA1 Region, Hippocampal/metabolism* ; Cognitive Dysfunction/metabolism* ; RNA-Binding Proteins/metabolism* ; Receptors, AMPA/metabolism*

Deactivation of the mitochondrial pyruvate dehydrogenase complex (PDC) is important for the metabolic switching of cancer cell from oxidative phosphorylation to aerobic glycolysis. Studies examining PDC activity regulation have mainly focused on the phosphorylation of pyruvate dehydrogenase (E1), leaving other post-translational modifications largely unexplored. Here, we demonstrate that the acetylation of Lys 488 of pyruvate dehydrogenase complex component X (PDHX) commonly occurs in hepatocellular carcinoma, disrupting PDC assembly and contributing to lactate-driven epigenetic control of gene expression. PDHX, an E3-binding protein in the PDC, is acetylated by the p300 at Lys 488, impeding the interaction between PDHX and dihydrolipoyl transacetylase (E2), thereby disrupting PDC assembly to inhibit its activation. PDC disruption results in the conversion of most glucose to lactate, contributing to the aerobic glycolysis and H3K56 lactylation-mediated gene expression, facilitating tumor progression. These findings highlight a previously unrecognized role of PDHX acetylation in regulating PDC assembly and activity, linking PDHX Lys 488 acetylation and histone lactylation during hepatocellular carcinoma progression and providing a potential biomarker and therapeutic target for further development.
Humans ; Acetylation ; Carcinoma, Hepatocellular/genetics* ; Liver Neoplasms/genetics* ; Pyruvate Dehydrogenase Complex/genetics* ; Gene Expression Regulation, Neoplastic ; Animals ; Mice ; Cell Line, Tumor ; Protein Processing, Post-Translational ; Histones/metabolism* ; Disease Progression

Ovarian cancer is the most lethal malignancy affecting the female reproductive system. Pharmacological inhibitors targeting CDK4/6 have demonstrated promising efficacy across various cancer types. However, their clinical benefits in ovarian cancer patients fall short of expectations, with only a subset of patients experiencing these advantageous effects. This study aims to provide further clinical and biological evidence for antineoplastic effects of a CDK4/6 inhibitor (TQB4616) in ovarian cancer and explore underlying mechanisms involved. Patient-derived ovarian cancer organoid models were established to evaluate the effectiveness of TQB3616. Potential key genes related to TQB3616 sensitivity were identified through RNA-seq analysis, and TRIM4 was selected as a candidate gene for further investigation. Subsequently, co-immunoprecipitation and GST pull-down assays confirmed that TRIM4 binds to hnRNPDL and promotes its ubiquitination through RING and B-box domains. RIP assay demonstrated that hnRNPDL binded to CDKN2C isoform 2 and suppressed its expression by alternative splicing. Finally, in vivo studies confirmed that the addition of siTRIM4 significantly improved the effectiveness of TQB3616. Overall, our findings suggest that TRIM4 modulates ubiquitin-mediated degradation of hnRNPDL and weakens sensitivity to CDK4/6 inhibitors in ovarian cancer treatment. TRIM4 may serve as a valuable biomarker for predicting sensitivity to CDK4/6 inhibitors in ovarian cancer.
Humans ; Female ; Ovarian Neoplasms/pathology* ; Animals ; Tripartite Motif Proteins/genetics* ; Mice ; Cyclin-Dependent Kinase 4/antagonists & inhibitors* ; Cell Line, Tumor ; Cyclin-Dependent Kinase 6/antagonists & inhibitors* ; Protein Kinase Inhibitors/pharmacology* ; Ubiquitin/metabolism* ; Xenograft Model Antitumor Assays ; Ubiquitination ; Antineoplastic Agents/pharmacology*