SUMO: From Bench to Bedside

Selective cerebral hypothermia alleviates focal cerebral ischemia/reperfusion injury via enhancing SUMO2/3 modification of Drp1 in rats

BACKGROUND

Selective Cerebral Hypothermia (SCH) has been demonstrated to potentiate SUMO2/3 modification, a native cellular safeguard against Cerebral Ischemia/Reperfusion Injury (CIRI). Dynamin-Related Protein 1 (Drp1), a pivotal regulator in the mitochondrial fission pathway, is an important substrate for SUMO2/3 modification. However, effects of SCH on SUMO2/3 modification of Drp1 remain undefined. Herein, the current study posits that SCH augments the SUMO2/3 modification of Drp1, thereby preserving mitochondrial integrity and mitigating CIRI.

METHODS

A focal CIRI model was established in Sprague-Dawley rats, with 20°C saline perfused via the transcarotid artery to induce SCH condition, and 37°C saline serving as a control. The modified Neurological Severity Score (mNSS) was used to quantitate the degree of neurological deficits. Staining of 2,3-5-triphenyltetrazolium chloride (TTC) was performed to detect cerebral infarction volume. Histological change of neurocyte was observed through Hematoxylin-eosin (HE) staining. Neurocyte apoptosis was evaluated using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) immunofluorescence staining. Western blot (WB) was utilized to evaluated the expressions of Drp1 and Cytochrome C. Co-immunoprecipitation was performed to evaluate the level of SUMO2/3 modification of Drp1. And transmission electron microscopy was used to observe the mitochondrial ultrastructure. The ratio of M-Drp1 to T-Drp1 and mitochondria morphological changes were observed under confocal microscopy.

RESULTS

Research data revealed that SCH significantly enhanced the SUMO2/3 modification of Drp1 when CIRI occurred. Concurrently, mNSSs, cerebral infarct volume, and apoptotic rates were notably attenuated in the SCH group, corroborating SCH's protective role. Expression levels of mitochondrial outer membrane Drp1 (M-Drp1), cytoplasmic cytochrome C (C-CytC), and ratio of M-Drp1 to T-Drp1 were reduced, and changes of mitochondrial ultrastructural and morphology were mitigated, underscoring SCH's inhibitory effect on mitochondrial fission. In contrast, 37°C saline displayed negligible protective impact while compare with 20°C saline perfusion.

CONCLUSIONS

The findings support that SCH amplifies SUMO2/3 modification of Drp1, curtails excessive mitochondrial fission, and consequently ameliorates focal CIRI in a rat model.

Increased SUMO-activating enzyme subunit 1 promotes glycolysis and fibrotic phenotype of diabetic nephropathy

Renal fibrosis is a prominent feature of diabetic nephropathy (DN), and the connection between renal fibrosis and abnormal glycolysis is not fully understood. SUMO-activating enzyme subunit 1 (SAE1) plays a crucial role in the SUMO modification process and is related to abnormal glycolysis. Despite this, the specific role of SAE1 in DN and its mechanism are not well defined. To investigate this, a streptozotocin-induced diabetic CD1 mice model was used, with SAE1 suppression achieved through systemic administration of SAE1 siRNA. In parallel, human renal proximal tubular tubule HK2 cells transfected with siSAE1 were exposed to high glucose for in vitro studies. The study revealed that SAE1 levels were elevated in diabetic kidney, and the deletion of SAE1 mitigated renal fibrosis in DN mice. Such suppression in SAE1 was associated with the lower expression of hypoxia inducible factor-1α (HIF-1α) and 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), these alterations subsequently improved abnormal glycolysis and mesenchymal transformations in vivo and in vitro. Further experiments discovered that SAE1 stabilized transcription factor HIF-1α expression through SUMOylation, promoting PFKFB3 transcription, which enhanced glycolysis characterized by increased PFK1 activity and lactate production. Additionally, pharmacological inhibition of PFKFB3 reduced renal fibrosis in DN mice, while overexpression of PFKFB3 partly restored the glycolysis and mesenchymal transformations inhibited by SAE1 knockdown in vitro. These data demonstrate that SAE1 promotes abnormal glycolysis by HIF-1α/PFKFB3 which is responsible for the fibrotic phenotype of diabetic kidney. Inhibition of SAE1 could be an alternative strategy in combating diabetes associated-kidney fibrosis via improving aberrant glycolysis.

Chemical approaches to explore ubiquitin-like proteins

Chemical protein synthesis has emerged as a powerful approach for producing ubiquitin (Ub) and ubiquitin-like modifiers (Ubls) in both their free and conjugated forms, particularly when recombinant or enzymatic strategies are challenging. By providing precise control over the assembly of Ub and Ubls, chemical synthesis enables the generation of complex constructs with site-specific modifications that facilitate detailed functional and structural studies. Ub and Ubls are central regulators of protein homeostasis, regulating a wide range of cellular processes such as cell cycle progression, transcription, DNA repair, and apoptosis. Ubls share an evolutionary link with Ub, resembling its structure and following a parallel conjugation pathway that results in a covalent isopeptide bond with their cellular substrates. Despite their structural similarities and sequence homology, Ub and Ubls exhibit distinct functional differences. Understanding Ubl biology is essential for unraveling how cells maintain their regulatory networks and how disruptions in these pathways contribute to various diseases. In this review, we highlight the chemical methodologies and strategies available for studying Ubls and advancing our comprehensive understanding of the Ubl system in health and disease.

SUMOylation regulates the aggressiveness of breast cancer-associated fibroblasts

BACKGROUND

Cancer-associated fibroblasts (CAFs) are the most abundant stromal cellular component in the tumor microenvironment (TME). CAFs contribute to tumorigenesis and have been proposed as targets for anticancer therapies. Similarly, dysregulation of SUMO machinery components can disrupt the balance of SUMOylation, contributing to tumorigenesis and drug resistance in various cancers, including breast cancer. We explored the role of SUMOylation in breast CAFs and evaluated its potential as a therapeutic strategy in breast cancer.

METHODS

We used pharmacological and genetic approaches to analyse the functional crosstalk between breast tumor cells and CAFs. We treated breast CAFs with the SUMO1 inhibitor ginkgolic acid (GA) at two different concentrations and conditioned media was used to analyse the proliferation, migration, and invasion of breast cancer cells from different molecular subtypes. Additionally, we performed quantitative proteomics (SILAC) to study the differential signalling pathways expressed in CAFs treated with low or high concentrations of GA. We confirmed these results both in vitro and in vivo. Moreover, we used samples from metastatic breast cancer patients to evaluate the use of GA as a therapeutic strategy.

RESULTS

Inhibition of SUMOylation with ginkgolic acid (GA) induces death in breast cancer cells but does not affect the viability of CAFs, indicating that CAFs are resistant to this therapy. While CAF viability is unaffected, CAF-conditioned media (CM) is altered by GA, impacting tumor cell behaviour in different ways depending on the overall degree to which SUMO1-SUMOylated proteins are dysregulated. Breast cancer cell lines exhibited a concentration-dependent response to conditioned media (CM) from CAFs. At a low concentration of GA (10 µM), there was an increase in proliferation, migration and invasion of breast cancer cells. However, at a higher concentration of GA (30 µM), these processes were inhibited. Similarly, analysis of tumor development revealed that at 10 µM of GA, the tumors were heavier and there was a greater degree of metastasis compared to the tumors treated with the higher concentration of GA (30 µM). Moreover, some of these effects could be explained by an alteration in the activity of the GTPase Rac1 and the activation of the AKT signalling pathway. The results obtained using SILAC suggest that different concentrations of GA affected cellular processes differentially, possibly influencing the secretome of CAFs. Treatment of metastatic breast cancer with GA demonstrated the use of SUMOylation inhibition as an alternative therapeutic strategy.

CONCLUSION

The study highlights the importance of SUMOylation in the tumor microenvironment, specifically in cancer-associated fibroblasts (CAFs). Targeting SUMOylation in CAFs affects their signalling pathways and secretome in a concentration-dependent manner, regulating the protumorigenic properties of CAFs.

Crosstalk between microRNA and inflammation; critical regulator of diabetes

A growing body of evidence indicates that microRNAs (miRNAs may be used as biomarkers for the diagnosis, prognosis, and treatment of diabetes, given their changed expression profile as the disease progresses. There is growing interest in using individual miRNAs or whole miRNA clusters linked to diabetes as therapeutic targets because of their abnormal expression and functioning. In diabetes, miRNAs are also involved in inflammatory and immunological responses. Additionally, the inflammatory response controls the generation, processing, and stability of pre- or mature miRNAs and miRNA biogenesis. With a comprehensive grasp of molecular biological activities and the signaling axis, this review emphasizes the critical functions of miRNAs in inflammatory and immunological processes in diabetes. We further emphasized the potential role of these miRNAs in controlling inflammation associated with diabetes. This assessment will direct the shift from many studies to practical applications for tailored diabetes treatment and assist in identifying new therapeutic targets and approaches.

SUMOylation facilitates the stability of BCR-ABL to promote chronic myeloid leukemia progression

Tyrosine kinase inhibitors (TKIs) targeting the oncoprotein BCR-ABL have improved the prognosis for patients with chronic myeloid leukemia (CML). However, TKI resistance and persistent expression of BCR-ABL are responsible for the relapse and progression of CML. Here, we describe a novel approach to induce BCR-ABL protein degradation by small ubiquitin-like modifier (SUMO) modification. The E3 SUMO ligase TRIM28, upregulated during the progression of CML, promoted SUMOylation of BCR-ABL, thereby inhibiting its binding to the autophagy receptor P62 and repressing its autophagic degradation. Accordingly, genetic and pharmacological inhibition of TRIM28 or SUMOylation suppressed progression in both the CML mouse model and patient-derived xenograft model. Furthermore, targeting SUMOylation of BCR-ABL restrained the proliferation of TKI-resistant CML cells. These results identify the mechanism by which TRIM28 maintains BCR-ABL stability to promote CML progression and suggest SUMOylation as a target for CML treatment.

The impact of dysregulation SUMOylation on prostate cancer

Prostate cancer (PCa) remains one of the most common malignancies in men, with its development and progression being governed by complex molecular pathways. SUMOylation, a post-translational modification (PTM) that involves the covalent attachment of small ubiquitin-like modifier (SUMO) proteins to target substrates, has emerged as a critical regulator of various cellular processes such as transcription, DNA repair, cell cycle progression, and apoptosis. Emerging evidence reveals that abnormal SUMOylation may contribute to PCa pathogenesis, and notably, SUMO-associated enzymes are commonly dysregulated in PCa. This review explores the mechanisms by which SUMOylation is implicated in the regulation of key pathways, and summary aberrant expression of SUMO-related enzymes or SUMOylation sites mutations of substrtes in PCa, as well as the therapeutic implications of targeting the SUMO-related enzymes in PCa treatment.

Genetic and pharmacologic enhancement of SUMO2 conjugation prevents and reverses cognitive impairment and synaptotoxicity in a preclinical model of Alzheimer's disease

INTRODUCTION

Amyloid beta oligomers (Aβos) are toxic to synapses and key to the progression of Alzheimer's disease (AD) and amyloid pathology, representing a target for therapeutic strategies.

METHODS

Amyloid and small ubiquitin modifier 2 (SUMO2) transgenics were analyzed by electrophysiology and behavioral testing. A recombinant analogue of SUMO2, SBT02, was generated and assessed for brain penetration and the ability to mitigate amyloid pathology.

RESULTS

Elevated SUMO2 expression prevents cognitive and synaptic impairment in a mouse model of AD amyloid pathology. Systemic administration of SBT02 resulted in high brain bioavailability and prophylactically halted the progression of AD-associated deficits. SBT02 also restored cognition and synaptic function in late-stage amyloid load. Mechanistically, SUMO2 and SBT02 do not alter amyloid processing or clearance and mitigate synaptotoxicity in the presence of high amyloid loads.

DISCUSSION

SBT02 is a promising therapeutic strategy to counteract and reverse the toxic effects of Aβos in AD.

HIGHLIGHTS

Genetic overexpression of human SUMO2 prevents the long-term potentiation (LTP) impairments and cognitive deficits in amyloid precursor protein (APP) transgenics without affecting amyloid pathology. A recombinant analogue of human SUMO2, termed SBT02, when administered systemically, displays high brain bioavailability and has no adverse effects at high doses. Prophylactic treatment of APP transgenics with SBT02 prior to the development of amyloid pathology results in the prevention of synaptic and behavioral dysfunction. SBT02 also reverses pre-existing LTP and cognitive impairments when administered to APP transgenics with advanced and severe pathology. SBT02 has no impact on amyloid pathology, indicating a mechanism of action on synaptic resistance to Aβ toxicity.

Microglia TRPC1 SUMOylation drives neuroinflammation after stroke by modulating NLRP3 activity via increasing TRPC1 interaction with ARRB2

Microglial canonical transient receptor potential channel 1 (TRPC1) has been proposed to influence neuroinflammation after cerebral ischemia and reperfusion injury (CIRI), however, the underlying mechanism remains poorly understood. This study demonstrates that TRPC1 is modified by small ubiquitin-related modifier (SUMO)ylation. Our findings suggest a notable increase in microglial TRPC1 SUMOylation within both the middle cerebral artery occlusion reperfusion (MCAO/R) model and the in vitro oxygen-glucose deprivation/regeneration model. Mice with a loss of TRPC1 SUMOylation in microglia exhibited improved stroke outcomes including reduced behavior deficits, infarct volume, blood brain barrier damage as well as neuronal apoptosis. Mechanistically, SUMOylation of microglial TRPC1 exacerbated neutrophil infiltration into the peri-infarct area. Additionally, SUMOylated TRPC1 activates the Nod-like receptor protein (NLRP) 3 signaling pathway in microglia and stimulates multiple CC-chemokine ligands and C-X-C motif ligand chemokines after MCAO/R. SUMOylated TRPC1 facilitates the interaction between TRPC1 and β-arrestin2 (ARRB2), a negative regulator of NLRP3 inflammasome, which disrupts the NLPR3/ARRB2 complex and stimulates the activation of the NLPR3 signaling pathway. Furthermore, ARRB2 directly binds to the residues 46 to 61 of TRPC1 N terminus, which is enhanced by TRPC1 SUMOylation. Collectively, our findings demonstrate a previously unidentified mechanism by which SUMOylated TRPC1 in microglia regulates leukocyte infiltration after stroke, suggesting that the inhibition of microglial TRPC1 SUMOylation may provide therapeutic benefits for CIRI.

p66Shc Mediates SUMO2-induced Endothelial Dysfunction

Background

Sumoylation is a post-translational modification that can regulate different physiological functions. Increased sumoylation, specifically conjugation of SUMO2/3 (small ubiquitin-like modifier 2/3), is detrimental to vascular health. However, the molecular mechanism mediating this effect is poorly understood.

Methods

We used cell-based assays and mass spectrometry to show that p66Shc is a direct target of SUMO2 and SUMO2 regulates p66Shc function via lysine-81 modification. To determine the effects of SUMO2-p66ShcK81 on vascular function, we generated p66ShcK81R knockin mice and crossbred to LDLr -/- mice to induce hyperlipidemia. Next, to determine p66ShcK81-SUMO2ylation-induced changes in endothelial cell signaling, we performed mass spectrometry followed by Ingenuity Pathway Analysis.

Results

Our data reveal that p66Shc mediates the effects of SUMO2 on endothelial cells. Mass spectrometry identified that SUMO2 modified lysine-81 in the unique collagen homology-2 domain of p66Shc. SUMO2ylation of p66Shc increased phosphorylation at serine-36, causing it to translocate to the mitochondria, a step critical for oxidative function of p66Shc. Notably, sumoylation-deficient p66Shc (p66ShcK81R) was resistant to SUMO2-induced p66ShcS36 phosphorylation and mitochondrial translocation. P66ShcK81R knockin mice were resistant to endothelial dysfunction induced by SUMO2ylation and hyperlipidemia. Ingenuity Pathway Analysis revealed multiple signaling pathways regulated by p66ShcK81-SUMO2ylation in endothelial cells, highlighting Rho-GTPase as a major pathway affected by SUMO2-p66ShcK81.

Conclusions

Collectively, our work reveals SUMO2-p66Shc signaling as a fundamental regulator of vascular endothelial function. We discovered that p66ShcK81 is an upstream modification regulating p66Shc signaling and mediates hyperlipidemia-induced endothelial dysfunction and oxidative stress.

Implication of protein post translational modifications in gastric cancer

Gastric cancer (GC) is one of the most common and highly lethal malignant tumors worldwide, and its occurrence and development are regulated by multiple molecular mechanisms. Post-translational modifications (PTM) common forms include ubiquitylation, phosphorylation, acetylation and methylation. Emerging research has highlighted lactylation and glycosylation. The diverse realm of PTM and PTM crosstalk is linked to many critical signaling events involved in neoplastic transformation, carcinogenesis and metastasis. This review provides a comprehensive overview of the impact of PTM on the occurrence and progression of GC. Specifically, aberrant PTM have been shown to alter the proliferation, migration, and invasion capabilities of GC cells. Moreover, PTM are closely associated with resistance to chemotherapeutic agents in GC. Notably, this review also discusses the phenomenon of PTM crosstalk, highlighting the interactions among PTM and their roles in regulating signaling pathways and protein functions. Therefore, in-depth investigation into the mechanisms of PTM and the development of targeted therapeutic strategies hold promise for advancing early diagnosis, treatment, and prognostic evaluation of GC, offering novel insights and future research directions.

The crosstalk between SUMOylation and immune system in host-pathogen interactions

Pathogens can not only cause infectious diseases, immune system diseases, and chronic diseases, but also serve as potential triggers or initiators for certain tumors. They directly or indirectly damage human health and are one of the leading causes of global deaths. Small ubiquitin-like modifier (SUMO) modification, a type of protein post-translational modification (PTM) that occurs when SUMO groups bond covalently to particular lysine residues on substrate proteins, plays a crucial role in both innate and adaptive immunologic responses, as well as pathogen-host immune system crosstalk. SUMOylation participates in the host's defense against pathogens by regulating immune responses, while numerically vast and taxonomically diverse pathogens have evolved to exploit the cellular SUMO modification system to break through innate defenses. Here, we describe the characteristics and multiple functions of SUMOylation as a pivotal PTM mechanism, the tactics employed by various pathogens to counteract the immune system through targeting host SUMOylation, and the character of the SUMOylation system in the fight between pathogens and the host immune system. We have also included a summary of the potential anti-pathogen SUMO enzyme inhibitors. This review serves as a reference for basic research and clinical practice in the diagnosis, prognosis, and treatment of pathogenic microorganism-caused disorders.

SENP6-Mediated deSUMOylation of Nrf2 Exacerbates Neuronal Oxidative Stress Following Cerebral Ischemia and Reperfusion Injury

Oxidative stress is believed to play critical pathophysiological roles in ischemic brain injury, and the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway is recognized as the most crucial endogenous antioxidant stress damage route. Some research have demonstrated that Nrf2 play critical roles in oxidative stress after ischemic stroke, but the underlying mechanism are not fully elucidated. This study reveals that Nrf2 is modified by SUMOylation and identifies Sentrin/SUMO-specific protease 6 (SENP6) as a negative regulator of Nrf2 SUMOylation. Notably, SENP6 binds to and mediates the deSUMOylation of Nrf2, which in turn inhibits antioxidant response by enhancing ubiquitination-dependent degradation of Nrf2, thereby reducing its transcriptional activity, inducing oxidative stress and aggravating neuronal apoptosis after ischemic stroke. Additionally, blocking the interaction between SENP6 and Nrf2 with a cell membrane-permeable peptide (Tat-Nrf2) preserves the SUMOylation of Nrf2, effectively attenuates oxidative stress, and rescues neurological functions in mice subjected to ischemic stroke. Furthermore, no toxicity is observed when high doses Tat-Nrf2 are injected into nonischemic mice. Collectively, this study uncovers a previously unidentified mechanism whereby SUMOylation of Nrf2 regulates oxidative stress and strongly indicates that interventions targeting SENP6 or its interaction with Nrf2 may provide therapeutic benefits for ischemic stroke.

SENP3: Cancers and diseases

SUMOylation is a protein modification process that involves the covalent attachment of a small ubiquitin-like modifier (SUMO) to a specific lysine residue on the target protein. This modification can influence the function, localization, stability, and interactions of proteins, thereby regulating various cellular processes. Altering the SUMOylation of certain proteins is expected to be a potential approach for treating specific cancers and diseases. Among these, SENP3 can affect target proteins by regulating the deSUMOylation process, which in turn influences the transcriptional activity of downstream genes, playing a role in either promoting or inhibiting cancer. SENP3 regulates the SUMO status of proteins in numerous signaling pathways, modulating the activity of specific signaling molecules to impact cellular responses and tumor progression. Additionally, SENP3 promotes cell growth and division by deSUMOylating key cyclins. In the context of DNA repair, SENP3 regulates the activity of proteins associated with DNA repair by deSUMOylating repair factors, thereby enhancing DNA repair and maintaining genome stability. Furthermore, SENP3 has specific functions in various other diseases. The complex roles of SENP3 indicate its potential as both a therapeutic target and a biomarker.

Identification of SUMOylation-related signature genes associated with immune infiltration in ulcerative colitis through bioinformatics analysis and experimental validation

OBJECTIVE

Ulcerative colitis (UC) is a chronic inflammatory disorder challenging to diagnose clinically. We focused on identifying and validating SUMOylation-related signature genes in UC and their association with immune infiltration.

METHODS

Five eligible gene expression profiles were selected from the Gene Expression Omnibus (GEO) database and merged into a single dataset comprising 260 UC patients and 76 healthy controls (HC). Differentially expressed genes (DEGs) were identified, and these were intersected with SUMOylation-related genes to obtain differentially expressed SUMOylation-related genes (DESRGs). Next, we identify the signature genes and validate them through comprehensive analyses employing GO, KEGG, GSVA, Lasso-cox regression, ROC curves, and clustering analysis. The infiltrating immune cells were analyzed using the CIBERSORT algorithm and Pearson correlation analysis. Finally, in vitro and in vivo experiments validated the identified signature genes.

RESULTS

PALMD, THRB, MAGED1, PARP1, and SLC16A1 were identified. Next, an excellent predictive model for UC was established and distinct subgroups of patients associated with SUMOylation were identified. Moreover, the NF-κB signaling pathway likely plays a pivotal role in the regulation of SUMOylation in UC. Additionally, we validated that the alterations in PALMD, THRB, and MAGED1 expression in LPS-induced Caco-2 cells concurred with our bioinformatics findings, particularly demonstrating statistically significant differences in PALMD and THRB expression. Finally, in a DSS-induced mouse colitis model, we observed a significant upregulation of PALMD expression. Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation.

CONCLUSION

This study comprehensively elucidates the biological roles of SUMOylation-related genes in UC, identifying PALMD, MAGED1, THRB, PARP1, and SLC16A1 as signature genes that represent promising biomarkers for UC diagnosis and prognosis.

Redox regulation of TRIM28 facilitates neuronal ferroptosis by promoting SUMOylation and inhibiting OPTN-selective autophagic degradation of ACSL4

Ferroptosis is one of the cell death programs occurring after spinal cord injury (SCI) and is driven by iron-dependent phospholipid peroxidation. However, little is known about its underlying regulation mechanism. The present study demonstrated that lipid peroxidation was promoted in patients with SCI. Neurons affected by ferroptosis following SCI had a high expression of ferroptotic protein ACSL4. The E3 SUMOylase TRIM28 promoted neuronal ferroptosis by enhancing ACSL4 expression. Genetic deletion of Trim28 significantly attenuated neuronal ferroptosis and improved mouse hindlimb motor function following SCI. In contrast, mice with Trim28 overexpression demonstrated poor neurological function after SCI, which was attenuated by ferroptosis inhibitor Liproxstatin-1. Mechanistically, TRIM28 bound to ACSL4, promoted SUMO3 modification at lysine (K) 532, and inhibited K63-linked ACSL4 ubiquitination, thereby suppressing OPTN-dependent autophagic degradation. Additionally, SENP3 was identified as the deSUMOylation enzyme that can reverse this process and compete with TRIM28, which was transcriptionally upregulated due to excessive oxidative stress. These data unveiled a mechanism by which TRIM28-mediated SUMOylation regulated neuronal ACSL4 levels and ferroptosis, identified interactions and correlations involved in ACSL4 SUMOylation, ubiquitination, and autophagic degradation, and discovered a positive feedback loop where oxidative stress transcriptionally upregulated Trim28, and conversely TRIM28 promoted ferroptosis and oxidative stress. Notably, screening of the FDA-approved drug library revealed that pharmacological TRIM28/ACSL4 axis interventions with Rutin hydrate inhibited neuronal ferroptosis and improved hindlimb motor function in mice after SCI, thus providing a promising therapeutic strategy for its treatment.

Discovery of paradoxical genes: reevaluating the prognostic impact of overexpressed genes in cancer

Oncogenes are typically overexpressed in tumor tissues and often linked to poor prognosis. However, recent advancements in bioinformatics have revealed that many highly expressed genes in tumors are associated with better patient outcomes. These genes, which act as tumor suppressors, are referred to as "paradoxical genes." Analyzing The Cancer Genome Atlas (TCGA) confirmed the widespread presence of paradoxical genes, and KEGG analysis revealed their role in regulating tumor metabolism. Mechanistically, discrepancies between gene and protein expression-affected by pre- and post-transcriptional modifications-may drive this phenomenon. Mechanisms like upstream open reading frames and alternative splicing contribute to these inconsistencies. Many paradoxical genes modulate the tumor immune microenvironment, exerting tumor-suppressive effects. Further analysis shows that the stage- and tumor-specific expression of these genes, along with their environmental sensitivity, influence their dual roles in various signaling pathways. These findings highlight the importance of paradoxical genes in resisting tumor progression and maintaining cellular homeostasis, offering new avenues for targeted cancer therapy.

SUMO-Specific Peptidase 5 Promotes Oesophageal Squamous Cell Carcinoma Growth through the NF-κB-SLC1A3 Axis

BACKGROUND

This study investigates the role of small ubiquitin-like modifier (SUMO)-specific peptidase 5 (SENP5), a key regulator of SUMOylation, in esophageal squamous cell carcinoma (ESCC), a lethal disease, and its underlying molecular mechanisms.

METHODS

Differentially expressed genes between ESCC mouse oesophageal cancer tissues and normal tissues were analysed via RNA-seq; among them, SENP5 expression was upregulated, and this gene was selected for further analysis. Immunohistochemistry and western blotting were then used to validate the increased protein level of SENP5 in both mouse and human ESCC samples. The Kaplan‒Meier method and multivariate analysis were used to analyse the relationship between SENP5 expression and ESCC prognosis. Stable SENP5-knockdown (KD) cell lines and conditional knockout (cKO) mice were established to verify the biological function of SENP5. Further RNA-seq comparisons between short hairpin SENP5 (shSENP5)- and short hairpin negative control (shNC)-transfected ESCC cell lines were conducted, and the nuclear factor kappa B (NF-κB)-SLC1A3 axis was identified through bioinformatics analysis. The correlation of SENP5 with signalling pathway components was validated via real-time quantitative PCR (qPCR), western blotting (WB), and immunoprecipitation.

RESULTS

Our study revealed that SENP5 was upregulated in human and mouse ESCC samples, and clinical data analysis revealed a correlation between high SENP5 expression and poor patient prognosis. SENP5 knockdown inhibited tumorigenesis and growth in vivo and suppressed the proliferation, migration, and invasion of ESCC cell lines in vitro. Our study also revealed that SENP5 knockdown enhanced the SUMO1-mediated SUMOylation of NF-kappa-B inhibitor alpha (IκBα), thereby inhibiting the activation of the NF-κB-SLC1A3 axis, which subsequently suppresses ESCC cell energy metabolism and impedes ESCC progression.

CONCLUSIONS

Suppression of SENP5 slows the development of ESCC by inhibiting the NF-κB‒SLC1A3 axis through SUMO1-mediated SUMOylation of IκBα. Our research suggests that SENP5 could serve as a prognostic indicator and a target for therapeutic intervention for ESCC patients.

Mechanisms and therapeutic implications of gene expression regulation by circRNA-protein interactions in cancer

Circular RNAs (circRNAs) have garnered substantial attention due to their distinctive circular structure and gene regulatory functions, establishing them as a significant class of functional non-coding RNAs in eukaryotes. Studies have demonstrated that circRNAs can interact with RNA-binding proteins (RBPs), which play crucial roles in tumorigenesis, metastasis, and drug response in cancer by influencing gene expression and altering the processes of tumor initiation and progression. This review aims to summarize the recent advances in research on circRNA-protein interactions (CPIs) and discuss the functions and mode of action of CPIs at various stages of gene expression, including transcription, splicing, translation, and post-translational modifications in the context of cancer. Additionally, we explore the role of CPIs in tumor drug resistance to gain a deeper understanding of their potential applications in the development of new anti-cancer therapeutic approaches.

SENP3 inhibition suppresses hepatocellular carcinoma progression and improves the efficacy of anti-PD-1 immunotherapy

The importance of SUMOylation in tumorigenesis has received increasing attention, and research on therapeutic agents targeting this pathway has progressed. However, the potential function of SUMOylation during hepatocellular carcinoma (HCC) progression and the underlying molecular mechanisms remain unclear. Here, we identified that SUMO-Specific Peptidase 3 (SENP3) was upregulated in HCC tissues and correlated with a poor prognosis. Multiple functional experiments demonstrated that SENP3 promotes the malignant phenotype of HCC cells. Mechanistically, SENP3 deSUMOylates RACK1 and subsequently increases its stability and interaction with PKCβII, thereby promoting eIF4E phosphorylation and translation of oncogenes, including Bcl2, Snail and Cyclin D1. Additionally, tumor-intrinsic SENP3 promotes the infiltration of tumor-associated macrophages (TAMs) while reducing cytotoxic T cells to facilitate immune evasion. Mechanistically, SENP3 promotes translation of CCL20 via the RACK1 /eIF4E axis. Liver-specific knockdown of SENP3 significantly inhibits liver tumorigenesis in a chemically induced HCC model. SENP3 inhibition enhances the therapeutic efficacy of PD-1 blockade in an HCC mouse model. Collectively, SENP3 plays cell-intrinsic and cell-extrinsic roles in HCC progression and immune evasion by modulating oncogene and cytokine translation. Targeting SENP3 is a novel therapeutic target for boosting HCC responsiveness to immunotherapy.

Targeting protein modification: a new direction for immunotherapy of pancreatic cancer

Post-translational modifications (PTMs) alter protein conformation by covalently attaching functional groups to substrates, influencing their biological activity, mechanisms of action, and functional performance. PTMs and their interactions are essential to many critical signal transduction processes, including tumor transformation, cancer progression, and metastasis in pancreatic cancer. Additionally, advancements in tumor immunotherapy indicate that PTMs are essential in immune cell activation, transport, and energy metabolism. This study aimed to investigate the effects of different PTMs on immunotherapy for pancreatic cancer, providing new perspectives and suggesting directions for future research.

SENP3 knockdown improves motor and cognitive impairments in the intranasal MPTP rodent model of Parkinson's disease

Several mechanisms underlying Parkinson's disease (PD) remain unclear, and effective treatments are still lacking. The conjugation of the small ubiquitin-like modifier (SUMO), known as SUMOylation, to key proteins in PD has shown potential beneficial effects. Considering that this process is reversed by SUMO-specific proteases (SENPs), this study addressed the effects of increased SUMO-2/3 conjugation, mediated by SENP3 knockdown, in the intranasal 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) rodent model of PD. Two weeks after infusion of the shRNA-containing lentiviral vector into the dorsolateral striatum and one week following intranasal MPTP administration, male Wistar rats were evaluated using cognitive and motor behavioural tests. Infection efficiency was confirmed by detecting GFP expression in the dorsolateral striatum. SENP3 knockdown, verified by Western blotting, resulted in increased SUMO-2/3 conjugation. MPTP-administered rats displayed impairments in both recognition and spatial memories, while SENP3 knockdown prevented these deficits. Rats exposed to MPTP also exhibited motor dysfunction, which was ameliorated by SENP3 knockdown. These findings underscore the involvement of SUMO-2/3 conjugation in PD and its potential as a novel therapeutic target to counteract cognitive and motor impairments induced by neurodegeneration.

Repression of the SUMO-conjugating enzyme UBC9 is associated with lowered double minutes and reduced tumor progression

Double minutes (DMs), extrachromosomal gene fragments found within certain tumors, have been noted to carry onco- and drug resistance genes contributing to tumor pathogenesis and progression. After screening for SUMO-related molecule expression within various tumor sample and cell line databases, we found that SUMO-conjugating enzyme UBC9 has been associated with genome instability and tumor cell DM counts, which was confirmed both in vitro and in vivo. Karyotyping determined DM counts post-UBC9 knockdown or SUMOylation inhibitor 2-D08, while RT-qPCR and Western blot were used to measure DM-carried gene expression in vitro. In vivo, fluorescence in situ hybridization (FISH) identified micronucleus (MN) expulsion. Western blot and immunofluorescence staining were then used to determine DNA damage extent, and a reporter plasmid system was constructed to detect changes in homologous recombination (HR) and non-homologous end joining (NHEJ) pathways. Our research has shown that UBC9 inhibition is able to attenuate DM formation and lower DM-carried gene expression, in turn reducing tumor growth and malignant phenotype, via MN efflux of DMs and lowering NHEJ activity to increase DNA damage. These findings thus reveal a relationship between heightened UBC9 activity, increased DM counts, and tumor progression, providing a potential approach for targeted therapies, via UBC9 inhibition.

Bone marrow stromal cells protect myeloma cells from ferroptosis through GPX4 deSUMOylation

Bone marrow stromal cells (BMSCs) are vital for preventing chemotherapy induced apoptosis of multiple myeloma (MM), but roles and machinery in other forms of cell death have not been well elucidated. Here, using an in vitro BMSC-MM interacting model, we observed BMSCs protected MM cells from labile iron pool (LIP) and reactive oxygen species (ROS) triggered ferroptosis by elevating glutathione peroxidase 4 (GPX4). Mechanistically, direct interaction with BMSCs upregulated the expression of SUMO-specific protease 3 (SENP3) in MM cells through CD40/CD40L signaling pathway, and SENP3 de-conjugated SUMO2 at lysine 75 residue to stabilize GPX4 protein, thereby consuming ROS to obviate ferroptosis in MM cells from the Vk∗MYC mouse model, as well as in CD138+B220- cells separated from the Cd40lfl/fl;Prx1Cre/+ mice (CD40-CKO) and Sumo2 knock out (SUMO2-KO) mice. Using the NOD-scid IL2Rgammanull (NSG) mouse based xenograft model and intra-bone MM growth model, we validated that target SENP3 enhanced the killing effect of GPX4 inhibitor RSL3, thereby reduced tumor burden, prolonged survival of mice, and alleviated bone disruption of mice bearing MM tumors. Our study deciphers the mechanism of BMSCs preventing MM cells from spontaneous ferroptosis, and clarifies the therapeutic potential of non-apoptosis strategies in managing refractory or relapsed MM patients.

SENP3 mediates deSUMOylation of SIX1 to promote prostate cancer proliferation and migration

BACKGROUND

Sentrin/SUMO-specific protease 3 (SENP3) is essential to regulate protein stability and function in normal and cancer cells. Nevertheless, its role and action mechanisms in prostate cancer (PCa) remain elusive. Thus, clarification of SENP3's involvement and the SUMOylation process in PCa is pivotal for discovering potential targets and understanding SUMOylation dynamics.

METHODS

Cell viability, EdU staining, live cell imaging, and cell cycle assays were used to determine proliferation of PCa cells. Transwell and wound-healing assays were used to detect migration of PCa cells. The interaction between SENP3 and SIX1 was determined by co-immunoprecipitation, western blotting, and immunofluorescence assays. Xenograft models established on NOD-SCID mice were used to evaluate in vivo effects post SENP3 knockdown. Immunohistochemistry was performed to investigate the expression of SENP3 in PCa tissues.

RESULTS

This study found that SENP3 is highly expressed in PCa cell lines and tissues from PCa patients. Overexpressed SENP3 is associated with metastatic malignancy in PCa. Various in vivo and in vitro experiments confirmed that SENP3 promotes the proliferation and migration of PCa. In addition, SENP3 interacts with the SD domain of SIX1 and mediates its deSUMOylation and protein stability. Lys154 (K154) is required for the SUMOylation of SIX1. More importantly, SENP3 promotes the malignancy of PCa through the regulation of SIX1.

CONCLUSIONS

We unravel the significant role of SENP3 in regulating protein stability of SIX1 and progression of PCa, which may deepen our understanding of the SUMOylation modification and provide a promising target for management of metastatic PCa.

SUMO: A new perspective to decipher fibrosis

Fibrosis is characterized by excessive extracellular matrix (ECM) deposition resulting from dysregulated wound healing and connective tissue repair mechanisms. Excessive accumulation of ECM leads to fibrous tissue formation, impairing organ function and driving the progression of various fibrotic diseases. Recently, the role of small ubiquitin-like modifiers (SUMO) in fibrotic diseases has attracted significant attention. SUMO-mediated SUMOylation, a highly conserved posttranslational modification, participates in a variety of biological processes, including nuclear-cytosolic transport, cell cycle progression, DNA damage repair, and cellular metabolism. Conversely, SUMO-specific proteases cleave the isopeptide bond of SUMO conjugates, thereby regulating the deSUMOylation process. Mounting evidence indicates that SUMOylation and deSUMOylation regulate the functions of several proteins, such as Smad3, NF-κB, and promyelocytic leukemia protein, which are implicated in fibrotic diseases like liver fibrosis, myocardial fibrosis, and pulmonary fibrosis. This review summarizes the role of SUMO in fibrosis-related pathways and explores its pathological relevance in various fibrotic diseases. All evidence suggest that the SUMO pathway is important targets for the development of treatments for fibrotic diseases.

SUMOylation modulates mitochondrial dynamics in an in vitro rotenone model of Parkinson's disease

SUMOylation is a post-translational modification essential for various biological processes. SUMO proteins bind to target substrates in a three-step enzymatic pathway, which is rapidly reversible by the action of specific proteases, known as SENPs. Studies have shown that SUMOylation is dysregulated in several human disorders, including neurodegenerative diseases that are characterized by the progressive loss of neurons, mitochondrial dysfunction, deficits in autophagy, and oxidative stress. Considering the potential neuroprotective roles of SUMOylation, the aim of this study was to investigate the effects of SENP3 knockdown in H4 neuroglioma cells exposed to rotenone, an in vitro model of cytotoxicity that mimics dopaminergic loss in Parkinson's disease (PD). The current data show that SENP3 knockdown increases SUMO-2/3 conjugates, which is accompanied by reduced levels of the mitochondrial fission protein Drp1 and increased levels of the mitochondrial fusion protein OPA1. Of high interest, SENP3 knockdown prevented rotenone-induced superoxide production and cellular death. Taken together, these findings highlight the importance of SUMOylation in maintaining mitochondrial homeostasis and the neuroprotective potential of this modification in PD.

Ubiquitination in pyroptosis pathway: A potential therapeutic target for sepsis

Sepsis remains a significant clinical challenge, causing numerous deaths annually and representing a major global health burden. Pyroptosis, a unique form of programmed cell death characterized by cell lysis and the release of inflammatory mediators, is a crucial factor in the pathogenesis and progression of sepsis, septic shock, and organ dysfunction. Ubiquitination, a key post-translational modification influencing protein fate, has emerged as a promising target for managing various inflammatory conditions, including sepsis. This review integrates the current knowledge on sepsis, pyroptosis, and the ubiquitin system, focusing on the molecular mechanisms of ubiquitination within pyroptotic pathways activated during sepsis. By exploring how modulating ubiquitination can regulate pyroptosis and its associated inflammatory signaling pathways, this review provides insights into potential therapeutic strategies for sepsis, highlighting the need for further research into these complex molecular networks.

MicroRNA-145-5p inhibits the tumorigenesis of breast cancer through SENP2-regulated ubiquitination of ERK2

Breast carcinoma exhibits the highest incidence among various cancers and is the foremost cause of mortality in women. Increasing evidence shows that SUMOylation of proteins plays a critical role in the progression of breast cancer; however, the role of SENP2 and its molecular mechanism in breast cancer remain underexplored. Here, we discerned that SENP2 promoted the tumorigenesis of breast cancer both in vitro and in vivo. Furthermore, we identified that ERK2 was SUMOylated and that SENP2 played a role by deconjugating ERK2 SUMOylation in breast cancer. SUMOylation of ERK2 promoted its ubiquitin-proteasomal degradation, thus inhibiting the epithelial-to-mesenchymal transition in breast cancer cells. Furthermore, microRNA-145-5p (miR-145-5p) has emerged as a scarce commodity in breast cancer and binds to the 3'-untranslated region of SENP2 mRNA to govern the regulatory dynamics of SENP2 expression. Finally, miR-145-5p inhibits SENP2 transcription, enhances ERK2 SUMOylation, and ultimately suppresses the progression of breast cancer. These revelations suggest evolving ideas for the miR-145-5p-SENP2 axis in therapeutic intervention, thus heralding transformative prospects for the clinical management of breast cancer.

Advances in post-translational modifications and recurrent spontaneous abortion

Recurrent spontaneous abortion (RSA) is defined as two or more pregnancy loss, which affects approximately 1-2% of women's fertility. The etiology of RSA has not yet been fully revealed, which poses a great problem for clinical treatment. Post- translational modifications(PTMs) are chemical modifications that play a crucial role in the functional proteome. A considerable number of published studies have shown the relationship between post-translational modifications of various proteins and RSA. The study of PTMs contributes to elucidating the role of modified proteins in the pathogenesis of RSA, as well as the design of more effective diagnostic/prognostic tools and more targeted treatments. Most reviews in the field of RSA have only focused on RNA epigenomics research. The present review reports the latest research developments of PTMs related to RSA, such as glycosylation, phosphorylation, Methylation, Acetylation, Ubiquitination, etc.

Dysregulation of deubiquitinases in gastric cancer progression

Gastric cancer (GC), characterized by a high incidence rate, poses significant clinical challenges owing to its poor prognosis despite advancements in diagnostic and therapeutic approaches. Therefore, a comprehensive understanding of the molecular mechanisms driving GC progression is crucial for identifying predictive markers and defining treatment targets. Deubiquitinating enzymes (DUBs), also called deubiquitinases, function as reverse transcriptases within the ubiquitin-proteasome system to counteract protein degradation. Recent findings suggest that DUB dysregulation could be a crucial factor in GC pathogenesis. In this review, we examined recent research findings on DUBs in the context of GC, elucidating their molecular characteristics, categorizations, and roles while also exploring the potential mechanisms underlying their dysregulation in GC. Furthermore, we assessed the therapeutic efficacy of DUB inhibitors in treating malignancies and evaluated the prevalence of aberrant DUB expression in GC.

Single-Cell Spatial-Temporal Analysis of ZNF451 in Mediating Drug Resistance and CD8+ T Cell Dysfunction

Cisplatin is widely used to treat osteosarcoma, but recurrent cases often develop resistance, allowing the disease to progress and complicating clinical management. This study aimed to elucidate the immune microenvironment of osteosarcoma, providing insights into the mechanisms of recurrence and identifying potential therapeutic strategies. By analyzing multiple single-cell and bulk RNA-sequencing datasets, we discovered that the SUMOylation-related gene ZNF451 promotes osteosarcoma recurrence and alters its immune microenvironment. ZNF451 was found to importantly enhance the growth, migration, and invasion of resistant cells while also reducing their sensitivity to cisplatin and lowering their apoptosis rate. Moreover, our data indicated that ZNF451 plays a crucial role in bone resorption and epithelial-mesenchymal transition. ZNF451 also regulates CD8+ T cell function, leading to their exhaustion and transition to the CD8T.EXH state. Additionally, β-cryptoxanthin has been identified as a potential therapeutic agent that inhibits osteosarcoma progression by targeting ZNF451. In summary, these findings highlight the critical role of ZNF451 in promoting osteosarcoma progression and underscore its potential as a therapeutic target and biomarker for osteosarcoma.

Unraveling the role and mechanism of mitochondria in postoperative cognitive dysfunction: a narrative review

Postoperative cognitive dysfunction (POCD) is a frequent neurological complication encountered during the perioperative period with unclear mechanisms and no effective treatments. Recent research into the pathogenesis of POCD has primarily focused on neuroinflammation, oxidative stress, changes in neural synaptic plasticity and neurotransmitter imbalances. Given the high-energy metabolism of neurons and their critical dependency on mitochondria, mitochondrial dysfunction directly affects neuronal function. Additionally, as the primary organelles generating reactive oxygen species, mitochondria are closely linked to the pathological processes of neuroinflammation. Surgery and anesthesia can induce mitochondrial dysfunction, increase mitochondrial oxidative stress, and disrupt mitochondrial quality-control mechanisms via various pathways, hence serving as key initiators of the POCD pathological process. We conducted a review on the role and potential mechanisms of mitochondria in postoperative cognitive dysfunction by consulting relevant literature from the PubMed and EMBASE databases spanning the past 25 years. Our findings indicate that surgery and anesthesia can inhibit mitochondrial respiration, thereby reducing ATP production, decreasing mitochondrial membrane potential, promoting mitochondrial fission, inducing mitochondrial calcium buffering abnormalities and iron accumulation, inhibiting mitophagy, and increasing mitochondrial oxidative stress. Mitochondrial dysfunction and damage can ultimately lead to impaired neuronal function, abnormal synaptic transmission, impaired synthesis and release of neurotransmitters, and even neuronal death, resulting in cognitive dysfunction. Targeted mitochondrial therapies have shown positive outcomes, holding promise as a novel treatment for POCD.

Ubiquitin-like modification dependent proteasomal degradation and disease therapy

Although it is believed that ubiquitin (Ub) modification is required for protein degradation in the proteasome system (UPS), several proteins are subject to Ub-independent proteasome degradation, and in many cases ubiquitin-like (UBL) modifications, including neddylation, FAT10ylation, SUMOylation, ISGylation, and urmylation, are essential instead. In this Review, we focus on UBL-dependent proteasome degradation (UBLPD), on proteasome regulators especially shuttle factors and receptors, as well as potential competition and coordination with UPS. We propose that there is a distinct UBL-proteasome system (UBLPS) that might be underestimated in protein degradation. Finally, we investigate the association of UBLPD with muscle wasting and neurodegenerative diseases in which the proteasome is abnormally activated and impaired, respectively, and suggest strategies to modulate UBLPD for disease therapy.

Cotton BOP1 mediates SUMOylation of GhBES1 to regulate fibre development and plant architecture

The Arabidopsis BLADE-ON-PETIOLE (BOP) genes are primarily known for their roles in regulating leaf and floral patterning. However, the broader functions of BOPs in regulating plant traits remain largely unexplored. In this study, we investigated the role of the Gossypium hirsutum BOP1 gene in the regulation of fibre length and plant height through the brassinosteroid (BR) signalling pathway. Transgenic cotton plants overexpressing GhBOP1 display shorter fibre lengths and reduced plant height compared to the wild type. Conversely, GhBOP1 knockdown led to increased plant height and longer fibre, indicating a connection with phenotypes influenced by the BR pathway. Our genetic evidence supports the notion that GhBOP1 regulates fibre length and plant height in a GhBES1-dependent manner, with GhBES1 being a major transcription factor in the BR signalling pathway. Yeast two-hybrid, luciferase complementation assay and pull-down assay results demonstrated a direct interaction between GhBOP1 and GhSUMO1, potentially forming protein complexes with GhBES1. In vitro and in vivo SUMOylation analyses revealed that GhBOP1 functions in an E3 ligase-like manner to mediate GhBES1 SUMOylation and subsequent degradation. Therefore, our study not only uncovers a novel mechanism of GhBES1 SUMOylation but also provides significant insights into how GhBOP1 regulates fibre length and plant height by controlling GhBES1 accumulation.

CBX4 counteracts cellular senescence to desensitize gastric cancer cells to chemotherapy by inducing YAP1 SUMOylation

AIMS

As our comprehension of the intricate relationship between cellular senescence and tumor biology continues to evolve, the therapeutic potential of cellular senescence is gaining increasing recognition. Here, we identify chromobox 4 (CBX4), a Small Ubiquitin-related Modifier (SUMO) E3 ligase, as an antagonist of cellular senescence and elucidate a novel mechanism by which CBX4 promotes drug resistance and malignant progression of gastric cancer (GC).

METHODS

In vitro and in vivo models were conducted to investigate the manifestation and impact of CBX4 on cellular senescence and chemoresistance. High-throughput sequencing, chromatin immunoprecipitation, and co-immunoprecipitation techniques were utilized to identify the upstream regulators and downstream effectors associated with CBX4, revealing its intricate regulatory network.

RESULTS

CBX4 diminishes the sensitivity of GC cells to cellular senescence, facilitating chemoresistance and GC development by deactivating the senescence-related Hippo pathway. Mechanistically, low-dose cisplatin transcriptionally downregulates CBX4 through CEBPB. In addition, CBX4 preserves the stability and cytoplasm-nuclear transport of YAP1, the key player of Hippo pathway, by inducing SUMO1 modification at K97 and K280, which competitively inhibits YAP1-S127 phosphorylation.

CONCLUSIONS

Our study highlights the anti-senescence role of CBX4 and suggests that CBX4 inhibition in combination with low-dose cisplatin has the potential to overcome chemoresistance and effectively restrict GC progression.

SUMOylation modification of HNRNPK at the K422 site promotes invasion in glioblastoma

Glioblastoma multiforme (GBM) is a highly heterogeneous brain tumor with limited treatment options. Recent studies revealed cellular heterogeneity and the potential for interconversion between distinct cell types on the basis of RNA sequencing and single-cell analyses. The ability of different cell types to adapt to their surrounding environment and undergo transformation significantly complicates the study and treatment of GBM. In this study, we reveal that HNRNPK-SUMO1 expression is predominantly found in the GBM infiltration area. SUMOylation of the K422 residue of HNRNPK interferes with its DNA binding ability, thereby disrupting downstream transcription, and ultimately leading to transitions between different states of glioblastoma stem cells. Although the proneural subtype is considered to have a better prognosis, transitioning towards this state promotes tumor invasion. These findings serve as a reminder to exercise caution when considering treatments targeting specific cellular subtypes.

Peptidylprolyl isomerase A guides SENP5/GAU1 DNA-lncRNA triplex generation for driving tumorigenesis

The three-stranded DNA-RNA triplex hybridization is involved in various biological processes, including gene expression regulation, DNA repair, and chromosomal stability. However, the DNA-RNA triplex mediating mechanisms underlying tumorigenesis remain to be fully elucidated. Here, we show that peptidylprolyl isomerase A (PPIA) serves as anchor to recruit GAU1 lncRNA by interacting with exon 4 of GAU1 and enhances the formation of SENP5/GAU1 DNA-lncRNA triplex. Intriguingly, TFR4 region of GAU1 exon 3 and TTS4 region of SENP5 promoter DNA constitute fragments forming the SENP5/GAU1 triplex. The SENP5/GAU1 triplex subsequently triggers the recruitment of the methyltransferase SET1A to exon 1 of GAU1, leading to the enrichment of H3K4 trimethylation and the activation of SENP5 transcription for driving the tumorigenesis of gastric cancer in vitro and in vivo. Our study reveals a mechanism of PPIA-guided SENP5/GAU1 DNA-lncRNA triplex formation in tumorigenesis and providing a concept in the dynamics of isomerase assisted DNA-RNA hybridization.

Impact of RANGAP1 SUMOylation on Smad4 nuclear export by bioinformatic analysis and cell assays

Small Ubiquitin-like Modifier (SUMOylation) regulates a variety of cellular activities, and its dysregulation has been associated with glioma etiology. The aim of this research was to clarify the function of SUMOylation-related genes in glioma and determine relevant prognostic markers. The Cancer Genome Atlas (TCGA) Glioma and GSE16011 datasets were analyzed through bioinformatics to identify Ran GTPase activating protein 1 (RANGAP1) as the hub gene for further study. Experimental validation consisted of quantitative real-time polymerase chain reaction (qRT-PCR), western blotting (WB), and immunoprecipitation (IP) to evaluate RANGAP1 expression, function, and interaction with SUMO1. To assess the role of RANGAP1 knockdown and SUMOylation in glioma cells, various assays were conducted, including cell proliferation, migration, invasion, and apoptosis. In addition, cell cycle analysis and immunofluorescence were performed. Through bioinformatics, RANGAP1 was identified as a crucial prognostic gene for glioma. Experimental studies confirmed the downregulation of RANGAP1 in glioma cells and verified that RANGAP1 repair impedes tumor growth. When it comes to RANGAP1 silencing, it enhanced cell proliferation, invasion and migration. Additionally, SUMO1 was identified as a specific SUMO molecule coupled to RANGAP1, affecting the location of Sma and Mad related protein 4 (Smad4) in the nucleocytoplasm and the transforming growth factor (TGF)-β/Smad signaling pathway. The functional impact of RANGAP1 SUMOylation on cell proliferation and migration was further confirmed through experiments using a SUMOylation-impairing mutation (K524R). Our findings suggest that RANGAP1 may be a potential prognostic marker in gliomas and could play a role in regulating cell proliferation, migration, and invasion. SUMOylation of RANGAP1 is responsible for regulating the TGF-β/Smad signaling pathway, which is crucial for the progression of tumors. Further investigations and experiments are necessary to confirm these results.

Shaping cardiac destiny: the role of post-translational modifications on endoplasmic reticulum - mitochondria crosstalk in cardiac remodeling

Cardiac remodeling is a shared pathological change in most cardiovascular diseases. Encompassing both adaptive physiological responses and decompensated pathological changes. Anatomically, atrial remodeling is primarily caused by atrial fibrillation, whereas ventricular remodeling is typically induced by myocardial infarction, hypertension, or cardiomyopathy. Mitochondria, the powerhouse of cardiomyocytes, collaborate with other organelles such as the endoplasmic reticulum to control a variety of pathophysiological processes such as calcium signaling, lipid transfer, mitochondrial dynamics, biogenesis, and mitophagy. This mechanism is proven to be essential for cardiac remodeling. Post-translational modifications can regulate intracellular signaling pathways, gene expression, and cellular stress responses in cardiac cells by modulating protein function, stability, and interactions, consequently shaping the myocardial response to injury and stress. These modifications, in particular phosphorylation, acetylation, and ubiquitination, are essential for the regulation of the complex molecular pathways that underlie cardiac remodeling. This review provides a comprehensive overview of the crosstalk between the endoplasmic reticulum and mitochondria during cardiac remodeling, focusing on the regulatory effects of various post-translational modifications on these interactions.

Exploring potential targets for natural product therapy of DN: the role of SUMOylation

Diabetic nephropathy (DN) is a common and serious micro-vascular complication of diabetes and a leading cause of end-stage renal disease globally. This disease primarily affects middle-aged and elderly individuals, especially those with a diabetes history of over 10 years and poor long-term blood glucose control. Small ubiquitin-related modifiers (SUMOs) are a group of reversible post-translational modifications of proteins that are widely expressed in eukaryotes. SUMO proteins intervene in the progression of DN by modulating various signaling cascades, such as Nrf2-mediated oxidative stress, NF-κB, TGF-β, and MAPK pathways. Recent advancements indicate that natural products regulating SUMOylation hold promise as targets for intervening in DN. In a previous article published in 2022, we reviewed the mechanisms by which SUMOylation intervenes in renal fibrosis and presented a summary of some natural products with therapeutic potential. Therefore, this paper will focus on DN. The aim of this review is to elucidate the mechanism of action of SUMOylation in DN and related natural products with therapeutic potential, thereby summarising the targets and candidate natural products for the treatment of DN through the modulation of SUMOylation, such as ginkgolic acid, ginkgolide B, resveratrol, astragaloside IV, etc., and highlighting that natural product-mediated modulation of SUMOylation is a potential therapeutic strategy for the treatment of DN as a potential therapeutic strategy.

The role of ubiquitination in health and disease

Ubiquitination is an enzymatic process characterized by the covalent attachment of ubiquitin to target proteins, thereby modulating their degradation, transportation, and signal transduction. By precisely regulating protein quality and quantity, ubiquitination is essential for maintaining protein homeostasis, DNA repair, cell cycle regulation, and immune responses. Nevertheless, the diversity of ubiquitin enzymes and their extensive involvement in numerous biological processes contribute to the complexity and variety of diseases resulting from their dysregulation. The ubiquitination process relies on a sophisticated enzymatic system, ubiquitin domains, and ubiquitin receptors, which collectively impart versatility to the ubiquitination pathway. The widespread presence of ubiquitin highlights its potential to induce pathological conditions. Ubiquitinated proteins are predominantly degraded through the proteasomal system, which also plays a key role in regulating protein localization and transport, as well as involvement in inflammatory pathways. This review systematically delineates the roles of ubiquitination in maintaining protein homeostasis, DNA repair, genomic stability, cell cycle regulation, cellular proliferation, and immune and inflammatory responses. Furthermore, the mechanisms by which ubiquitination is implicated in various pathologies, alongside current modulators of ubiquitination are discussed. Enhancing our comprehension of ubiquitination aims to provide novel insights into diseases involving ubiquitination and to propose innovative therapeutic strategies for clinical conditions.

SENP3 mediates the deSUMOylation and degradation of YAP1 to regulate the progression of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a prevalent malignancy in women, casting a formidable shadow on their well-being. Positioned within the nucleolus, SUMO-specific protease 3 (SENP3) assumes a pivotal role in the realms of development and tumorigenesis. However, the participation of SENP3 in TNBC remains a mystery. Here, we elucidate that SENP3 exerts inhibitory effects on migration and invasion capacities, as well as on the stem cell-like phenotype, within TNBC cells. Further experiments showed that YAP1 is the downstream target of SENP3, and SENP3 regulates tumorigenesis in a YAP1-dependent manner. YAP1 is found to be SUMOylated and SENP3 deconjugates SUMOylated YAP1 and promotes degradation mediated by the ubiquitin-proteasome system. More importantly, YAP1 with a mutation at the SUMOylation site impedes the capacity of WT YAP1 in TNBC tumorigenesis. Taken together, our findings firmly establish the pivotal role of SENP3 in the modulation of YAP1 deSUMOylation, unveiling novel mechanistic insight into the important role of SENP3 in the regulation of TNBC tumorigenesis in a YAP1-dependent manner.

Protein posttranslational modifications in metabolic diseases: basic concepts and targeted therapies

Metabolism-related diseases, including diabetes mellitus, obesity, hyperlipidemia, and nonalcoholic fatty liver disease, are becoming increasingly prevalent, thereby posing significant threats to human health and longevity. Proteins, as the primary mediators of biological activities, undergo various posttranslational modifications (PTMs), including phosphorylation, ubiquitination, acetylation, methylation, and SUMOylation, among others, which substantially diversify their functions. These modifications are crucial in the physiological and pathological processes associated with metabolic disorders. Despite advancements in the field, there remains a deficiency in contemporary summaries addressing how these modifications influence processes of metabolic disease. This review aims to systematically elucidate the mechanisms through which PTM of proteins impact the progression of metabolic diseases, including diabetes, obesity, hyperlipidemia, and nonalcoholic fatty liver disease. Additionally, the limitations of the current body of research are critically assessed. Leveraging PTMs of proteins provides novel insights and therapeutic targets for the prevention and treatment of metabolic disorders. Numerous drugs designed to target these modifications are currently in preclinical or clinical trials. This review also provides a comprehensive summary. By elucidating the intricate interplay between PTMs and metabolic pathways, this study advances understanding of the molecular mechanisms underlying metabolic dysfunction, thereby facilitating the development of more precise and effective disease management strategies.

Transcription and post-translational mechanisms: dual regulation of adiponectin-mediated Occludin expression in diabetes

BACKGROUND

Occludin, a crucial component of tight junctions, has emerged as a promising biomarker for the diagnosis of acute ischemic disease, highlighting its significant potential in clinical applications. In the diabetes, Occludin serves as a downstream target gene intricately regulated by the adiponectin (APN) signaling pathway. However, the specific mechanism by which adiponectin regulates Occludin expression remains unclear.

METHODS AND RESULTS

Endothelial-specific Ocln knockdown reduced APN-mediated blood flow recovery after femoral artery ligation and nullified APN's protection against high-fat diet (HFD)-triggered apoptosis and angiogenesis inhibition in vivo. Mechanically, we have meticulously elucidated APN's regulatory role in Occludin expression through a comprehensive analysis spanning transcriptional and post-translational dimensions. Foxo1 has been elucidated as a crucial transcriptional regulator of Occludin that is modulated by the APN/APPL1 signaling axis, as evidenced by validation through ChIP-qPCR assays and Western blot analysis. APN hindered Occludin degradation via the ubiquitin-proteasome pathway. Mass spectrometry analysis has recently uncovered a novel phosphorylation site, Tyr467, on Occludin. This site responds to APN, playing a crucial role in inhibiting Occludin ubiquitination by APN. The anti-apoptotic and pro-angiogenic effects of APN were attenuated in vitro and in vivo following Foxo1 knockdown or expression of a non-phosphorylatable mutant, OccludinY467A. Clinically, elevated plasma concentrations of Occludin were observed in patients with diabetes. A significant negative correlation was found between Occludin levels and APN concentrations.

CONCLUSION

Our study proposes that APN modulates Occludin expression through mechanisms involving both transcriptional and post-translational interactions, thereby conferring a protective effect on endothelial integrity within diabetic vasculature.

Transcription factor E2F4 facilitates SUMOylation to promote HCC progression through interaction with LIN9

SUMOylation plays a crucial role in numerous cellular biological and pathophysiological processes associated with human disease; however, the mechanisms regulating the genes involved in SUMOylation remain unclear. In the present study, E2F transcription factor 4 (E2F4) was identified as an E2F member related to hepatocellular carcinoma (HCC) progression by public database analysis. It was found that E2F4 promoted the proliferation and invasiveness of HCC cells via SUMOylation using Soft agar and Transwell migration assays. Mechanistically, it was demonstrated that E2F4 upregulated the transcript and protein expression levels of baculoviral IAP repeat containing 5, cell division cycle associated 8 and DNA topoisomerase II α using western blotting. Furthermore, the interaction between E2F4 with lin‑9 DREAM multi‑vulva class B core complex component (LIN9) was explored by co‑immunoprecipitation, immunofluorescence co‑localization and bimolecular fluorescence complementation assays. Moreover, it was demonstrated that E2F4 promoted the progression of HCC cells via LIN9. Rescue experiments revealed that LIN9 facilitated the SUMOylation and proliferation of HCC cells, which was prevented by knocking down E2F4 expression. In conclusion, the findings of the present study indicated that E2F4 plays a major role in the proliferation of HCC cells and may be a potential therapeutic target in the future.

The role of the ubiquitin system in the onset and reversal of neuropathic pain

Neuropathic pain (NP) remains one of the world's most difficult problems, and people suffering from NP have their quality of life affected to a great extent and constantly suffer from pain. Sensitization of injurious receptors, ectopic firing of afferent nerves after nerve injury, and coupling between sympathetic and sensory neurons are involved in the onset or development of NP, but the pathogenesis of NP is still not well understood. We found that the ubiquitin system is involved in the pathogenesis of NP and has a crucial role in it. The ubiquitin system can be involved in the onset or reversal of NP by affecting ion channels, cellular signal transduction, glial cells, and the regulation of non-coding RNAs. This provides new ideas for the treatment of NP. The ubiquitin system may be a new effective target for the treatment of NP. A continued, in-depth understanding of the mechanisms of the ubiquitin system involved in NP could further refine the study of analgesic targets and improve pharmacological studies.

Dysfunction of Telomeric Cdc13-Stn1-Ten1 Simultaneously Activates DNA Damage and Spindle Checkpoints

Telomeres, the ends of eukaryotic linear chromosomes, are composed of repeated DNA sequences and specialized proteins, with the conserved telomeric Cdc13/CTC1-Stn1-Ten1 (CST) complex providing chromosome stability via telomere end protection and the regulation of telomerase accessibility. In this study, SIZ1, coding for a SUMO E3 ligase, and TOP2 (a SUMO target for Siz1 and Siz2) were isolated as extragenic suppressors of Saccharomyces cerevisiae CST temperature-sensitive mutants. ten1-sz, stn1-sz and cdc13-sz mutants were isolated next due to being sensitive to intracellular Siz1 dosage. In parallel, strong negative genetic interactions between mutants of CST and septins were identified, with septins being noticeably sumoylated through the action of Siz1. The temperature-sensitive arrest in these new mutants of CST was dependent on the G2/M Mad2-mediated and Bub2-mediated spindle checkpoints as well as on the G2/M Mec1-mediated DNA damage checkpoint. Our data suggest the existence of yet unknown functions of the telomeric Cdc13-Stn1-Ten1 complex associated with mitotic spindle positioning and/or assembly that could be further elucidated by studying these new ten1-sz, stn1-sz and cdc13-sz mutants.

Phosphatase LHPP confers prostate cancer ferroptosis activation by modulating the AKT-SKP2-ACSL4 pathway

LHPP, a novel, recognized tumor suppressor, exerts a critical influence on the regulation of tumor cell proliferation and survival by modulating various signaling pathways with its phosphatase activity. Here, we unveil a robust correlation between reduced LHPP expression and adverse prognosis in prostate cancer. We demonstrate that LHPP interacts with AKT, thereby dampening AKT phosphorylation and subsequently inhibiting ACSL4 phosphorylation at the T624 site. This interaction impedes phosphorylation-dependent ubiquitination, thwarting SKP2 from recognizing and binding to ACSL4 at the K621 site. As a result, ACSL4 is spared from lysosomal degradation, leading to its accumulation and the promotion of lipid peroxidation, and ferroptosis. Moreover, our findings reveal that Panobinostat, a potent histone-deacetylase inhibitor, intricately regulates LHPP expression at multiple levels through the inhibition of HDAC3. This complex modulation enhances the ferroptosis pathway, offering a novel mechanism for curtailing the growth of prostate tumors and highlighting its significant translational potential for clinical application.

SENP1-Mediated HSP90ab1 DeSUMOylation in Cardiomyocytes Prevents Myocardial Fibrosis by Paracrine Signaling

Myocardial infarction (MI) triggers a poor ventricular remodeling response, but the underlying mechanisms remain unclear. Here, the authors show that sentrin-specific protease 1 (SENP1) is downregulated in post-MI mice and in patients with severe heart failure. By generating cardiomyocyte-specific SENP1 knockout and overexpression mice to assess cardiac function and ventricular remodeling responses under physiological and pathological conditions. Increased cardiac fibrosis in the cardiomyocyte-specific SENP1 deletion mice, associated with increased fibronectin (Fn) expression and secretion in cardiomyocytes, promotes fibroblast activation in response to myocardial injury. Mechanistically, SENP1 deletion in mouse cardiomyocytes increases heat shock protein 90 alpha family class B member 1 (HSP90ab1) SUMOylation with (STAT3) activation and Fn secretion after ventricular remodeling initiated. Overexpression of SENP1 or mutation of the HSP90ab1 Lys72 ameliorates adverse ventricular remodeling and dysfunction after MI. Taken together, this study identifies SENP1 as a positive regulator of cardiac repair and a potential drug target for the treatment of MI. Inhibition of HSP90ab1 SUMOylation stabilizes STAT3 to inhibit the adverse ventricular remodeling response.