Ubiquitination in the regulation of inflammatory cell death and cancer

Sec13 promotes glycolysis by inhibiting Ubqln1 mediated Pgm1 ubiquitination in ALI

Acute lung injury (ALI) is a severe lung damage characterized by acute hypoxemia, increased pulmonary vascular permeability, and inflammatory reactions. Despite current treatments, mortality from ALI remains high. This study found that Sec13 is highly expressed in ALI and regulates it by glycolysis and epithelial-mesenchymal transition (EMT). In an ALI mouse model and cell model, Sec13 expression increased, accompanied by enhanced glycolysis, EMT, and inflammation. Sec13 knockdown suppressed these effects, alleviating ALI. Sec13 forms a protein complex with Pgm1, an enzyme regulating glucose-6-phosphate (G6P) production, and Ubqln1, an ubiquitin ligase. Sec13 inhibits Ubqln1-mediated Pgm1 ubiquitination, thereby stabilizing Pgm1. In ALI, Pgm1 binding to Sec13 increased but binding to Ubqln1 decreased. Sec13 knockdown decreased lactate, G6P, EMT markers, and inflammatory cytokines. Pgm1 knockdown produced similar effects. Ubqln1 overexpression suppressed inflammation but decreased Pgm1 expression. In conclusion, Sec13 plays a key role in ALI by inhibiting Ubqln1-mediated Pgm1 ubiquitination, affecting glycolysis and EMT. Sec13 and Pgm1 may be new targets for treating ALI.

USP5 promotes tumor progression by stabilizing SLUG in bladder cancer

Bladder cancer ranks as the second most prevalent urology malignancy globally. Invasive metastasis is a significant contributor to mortality among patients with bladder cancer, yet the underlying mechanisms remain elusive. Deubiquitinases are pivotal in carcinogenesis, with USP5 implicated in the malignant progression of hepatocellular carcinoma, colorectal cancer and non-small cell lung cancer. The present study assessed the role and mechanism of ubiquitin-specific proteinase 5 (USP5) in the malignant progression of bladder cancer. The association between USP5 expression and bladder cancer prognosis and stage was analyzed using The Cancer Genome Atlas database. Moreover, to elucidate the role of USP5 in bladder cancer, USP5 overexpression and knockdown cell lines were established using T24 cells. Cell viability, proliferation and migration were assessed using Cell Counting Kit-8, Transwell and scratch assays, respectively. Cyclohexanamide was used to evaluate the effect of USP5 expression on Snail family zinc finger 2 (SLUG) stability. Immunoprecipitation and immunofluorescence co-localization were utilized to probe the interaction between USP5 and SLUG. Changes in mRNA and protein levels were assessed using reverse transcription-quantitative PCR and western blotting, respectively. The results revealed that patients with bladder cancer with high USP5 expression had significantly shorter survival (P<0.05) and a higher clinicopathologic stage (P<0.05) than those with low USP5 expression. T24 cells overexpressing USP5 demonstrated significantly increased proliferation (P<0.05), invasion (P<0.05) and expression of epithelial-mesenchymal transition markers (P<0.05); whereas T24 cells with knocked-down USP5 expression revealed significantly reduced proliferation (P<0.05), invasion (P<0.05) and epithelial-mesenchymal transition markers (P<0.05). Immunoprecipitation experiments demonstrated the binding of USP5 to SLUG in bladder cancer cells, with further analysis revealing that USP5 upregulated protein levels of SLUG by inhibiting its ubiquitination. Furthermore, the treatment of bladder cancer cells with Degrasyn, a USP5 inhibitor, was associated with a significant inhibition of the proliferation (P<0.05) and invasion (P<0.05) of T24 cells. In conclusion, the findings of the present study underscore the role of USP5 in promoting the malignant progression of bladder cancer through the stabilization of SLUG. Targeting USP5 holds promise as a strategy for inhibiting bladder cancer progression.

The role of ACSL4 in stroke: mechanisms and potential therapeutic target

Stroke, as a neurological disorder with a poor overall prognosis, has long plagued the patients. Current stroke therapy lacks effective treatments. Ferroptosis has emerged as a prominent subject of discourse across various maladies in recent years. As an emerging therapeutic target, notwithstanding its initial identification in tumor cells associated with brain diseases, it has lately been recognized as a pivotal factor in the pathological progression of stroke. Acyl-CoA synthetase long-chain family member 4 (ACSL4) is a potential target and biomarker of catalytic unsaturated fatty acids mediating ferroptosis in stroke. Specifically, the upregulation of ACSL4 leads to heightened accumulation of lipid peroxidation products and reactive oxygen species (ROS), thereby exacerbating the progression of ferroptosis in neuronal cells. ACSL4 is present in various tissues and involved in multiple pathways of ferroptosis. At present, the pharmacological mechanisms of targeting ACSL4 to inhibit ferroptosis have been found in many drugs, but the molecular mechanisms of targeting ACSL4 are still in the exploratory stage. This paper introduces the physiopathological mechanism of ACSL4 and the current status of the research involved in ferroptosis crosstalk and epigenetics, and summarizes the application status of ACSL4 in modern pharmacology research, and discusses the potential application value of ACSL4 in the field of stroke.

Molecular mechanisms involved in therapeutic effects of natural compounds against cisplatin-induced cardiotoxicity: a review

Cisplatin is a widely used chemotherapeutic agent for the treatment of various cancers. However, the clinical use of cisplatin is limited by its cardiotoxic side effects. The primary mechanisms implicated in this cardiotoxicity include mitochondrial dysfunction, oxidative stress, inflammation, and apoptotic. Numerous natural compounds (NCs) have been introduced as promising protective factors against cisplatin-mediated cardiac damage. The current review summarized the potential of various NCs as cardioprotective agents at the molecular levels. These compounds exhibited potent antioxidant and anti-inflammatory effects by interaction with the PI3K/AKT, AMPK, Nrf2, NF-κB, and NLRP3/caspase-1/GSDMD pathways. Generally, the modulation of these signaling pathways by NCs represents a promising strategy for improving the therapeutic index of cisplatin by reducing its cardiac side effects.

The role and advance of ubiquitination and deubiquitination in depression pathogenesis and treatment

Depression is a common neuropsychiatric disease that is characterized by long-term, repeated low mood, pain and despair, pessimism, and even suicidal tendencies. Increasing evidence has shown that ubiquitination and deubiquitination are closely related to the occurrence of depression, including pathological morphogenesis, neuroplasticity, synaptic transmission, neuroinflammation, and so forth. The development of depression is regulated by intracellular proteins that undergo various posttranslational modifications, including ubiquitination, which falls under the epigenetics category. Although there have been studies and reviews of literature on epigenetics and depression, a systematic review of ubiquitination modification and depression has not been reported. In addition, with the deepening of research on depression and ubiquitination, the development of drugs targeting the ubiquitin system has gradually increased, but it is still not mature, so there is an urgent need to find new antidepressant drug targets. E3 ubiquitin ligases and deubiquitinating enzymes can regulate the occurrence and development of depression in a variety of ways, which may be a direction for the treatment of depression in the future. Therefore, this review describes the latest progress of ubiquitination and deubiquitination in the regulation of depression, summarizes the published signal pathways of ubiquitination and deubiquitination involved in depression, emphasizes the targets and mechanisms of E3 ubiquitin ligases and deubiquitinase in the regulation of depression, and further discusses the therapeutic targets of targeting ubiquitination modification systems to regulate depression.

Ubiquitination in osteosarcoma: unveiling the impact on cell biology and therapeutic strategies

Ubiquitination, a multifaceted post-translational modification, regulates protein function, degradation, and gene expression. The pivotal role of ubiquitination in the pathogenesis and progression of cancer, including colorectal, breast, and liver cancer, is well-established. Osteosarcoma, an aggressive bone tumor predominantly affecting adolescents, also exhibits dysregulation of the ubiquitination system, encompassing both ubiquitination and deubiquitination processes. This dysregulation is now recognized as a key driver of osteosarcoma development, progression, and chemoresistance. This review highlights recent progress in elucidating how ubiquitination modulates tumor behavior across signaling pathways. We then focus on the mechanisms by which ubiquitination influences osteosarcoma cell function. Finally, we discuss the potential for targeting the ubiquitin-proteasome system in osteosarcoma therapy. By unraveling the impact of ubiquitination on osteosarcoma cell physiology, we aim to facilitate the development of novel strategies for prognosis, staging, treatment, and overcoming chemoresistance.

USP14 Modulates Cell Pyroptosis and Ameliorates Doxorubicin-Induced Cardiotoxicity by Deubiquitinating and Stabilizing SIRT3

This study investigates the role of the deubiquitinating enzyme USP14 in alleviating doxorubicin (DOX)-induced cardiotoxicity(DIC), particularly concerning its mechanism of regulating pyroptosis through the stabilization of the mitochondrial protein SIRT3. Using in vivo and in vitro models, the research demonstrated that USP14 overexpression protects against DOX-induced cardiac damage by modulating pyroptosis. Silencing SIRT3 via siRNA revealed that SIRT3 is a key intermediary molecule in USP14-mediated regulation of pyroptosis. Notably, DOX exposure resulted in decreased USP14 expression, while its overexpression preserved mitochondrial function and reduced oxidative stress by stabilizing SIRT3. Immunoprecipitation confirmed that USP14 stabilizes SIRT3 through deubiquitination. These findings position USP14 as a promising therapeutic target for mitigating DOX-induced cardiotoxicity by stabilizing SIRT3 and maintaining mitochondrial integrity, suggesting potential novel strategies for cardio-protection in chemotherapy.

Implications of ITCH-mediated ubiquitination of SIX1 on CDC27-cyclinB1 signaling in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) presents a significant medical challenge due to its high incidence rate and poor prognosis, which are attributed primarily to tumor metastasis and drug resistance. Sine oculis homeobox homolog 1 (SIX1) has been identified as a crucial target for cancer treatment. However, its role in NPC remains incompletely understood. This study investigated the mechanisms by which the degradation of the SIX1 protein, which is mediated by ubiquitin, affects the malignant characteristics of NPC throughout the cell cycle. Our findings reveal that reduced expression of the itchy E3 ubiquitin ligase E3 (ITCH) in NPC impedes the degradation of the SIX1 protein, leading to enhance oncogenic properties. Knockdown experiments which SIX1 was inhibited demonstrated a decrease in the proliferation, migration, and invasion of NPC cell lines, whereas overexpression of SIX1 yielded the opposite effects. Further experimental validation revealed that SIX1 promotes NPC progression via the cell division cycle 27 (CDC27)/cyclin B1 axis. These findings provide valuable insights into potential therapeutic targets and prognostic indicators for NPC treatment, emphasizing the ITCH/SIX1/CDC27/cyclin B1 axis as a promising target for novel therapies.

Fangchinoline suppresses hepatocellular carcinoma by regulating ROS accumulation via the TRIM7/Nrf2 signaling pathway

BACKGROUND

Dysregulation of redox homeostasis is associated with developing hepatocellular carcinoma (HCC). Oxidative stress (OS) is distinguished by the accumulation of ROS, which plays a variety of roles in cancer pathology. Fangchinoline (FAN), a bis-benzylisoquinoline alkaloid, has anti-cancer pharmacological activity. However, the regulatory mechanism of FAN on OS and whether it can inhibit HCC by mediating OS are still unclear.

HYPOTHESIS/PURPOSE

This paper aims to explore the effectiveness of FAN in preventing HCC via regulating OS and identify the underlying molecular mechanisms.

METHODS

We used the primary HCC mouse model and hepatoma cell line to explore the suppressive effect of FAN on hepatocarcinogenesis. To study the role of ROS in the anti-hepatocarcinoma effect of FAN in cell model and mouse model. The mechanism of FAN-induced nuclear factor erythroid 2-related factor 2 (Nrf2) pathway activation was studied through various techniques, including generation of Nrf2 and tripartite motif containing 7 (TRIM7) gene overexpressing or knockdown cell model, co-immunoprecipitation, immunohistochemistry and subcutaneous tumor xenograft models constructed by the stable TRIM7-overexpression HLE cells, etc. RESULTS: We showed that FAN significantly inhibited cell proliferation and hepatocarcinogenesis in HCC cells and primary HCC mouse model. The FAN-induced mitochondrial dysfunction promoted ROS accumulation, and using N-Acetylcysteine to clear ROS reversed the anti-HCC effects of FAN. We observed that FAN is capable of activating the Nrf2 pathway. This effect was thought to be due to the fact that, in response to the FAN-induced OS, the cancer cells created a feedback loop to stable Nrf2 via depressing the K48-linkage ubiquitination of it, which was caused by reduced binding of kelch-like ECH-associated protein 1 (Keap1) and Nrf2 and elevated TRIM7 expression. Indeed, overexpression of TRIM7 suppressed the anti-hepatocarcinoma effect of FAN.

CONCLUSION

The study determines the anti-liver cancer effect of FAN and first describes the positive regulatory effect of TRIM7 on Nrf2 signaling. We reveal that TRIM7/Nrf2 signaling served as a target of FAN-induced ROS accumulation in HCC, which helps to clarify the mechanism of action of FAN against HCC and provides a theoretical basis for FAN as an anti-cancer drug.

Chemical Diversification of Enzymatically Assembled Polyubiquitin Chains to Decipher the Ubiquitin Codes Programmed on the Branch Structure

The multimerization of ubiquitins at different positions of lysine residues to form heterotypic polyubiquitin chains is a post-translational modification that is essential for the precise regulation of protein functions and degradative fates in living cells. The understanding of structure-activity relationships underlying their diverse properties has been seriously impeded by difficulties in the preparation of a series of folded heterotypic chains appropriately functionalized with different chemical tags for the systematic evaluation of their multifaceted functions. Here, we report a chemical diversification of enzymatically assembled polyubiquitin chains that enables the facile preparation of folded heterotypic chains with different functionalities. By introducing an acyl hydrazide at the C terminus of the proximal ubiquitin, polyubiquitin chains were readily diversified from the same starting materials with a variety of molecules, ranging from small molecules to biopolymers, under nondenaturing conditions. This chemical diversification allowed the systematic study of the functional differences of K63/K48 heterotypic chains based on the position of the branch point during enzymatic deubiquitination and proteasomal proteolysis, thus demonstrating critical roles of the branch position in both the positive and negative control of ubiquitin-mediated reactions. The chemical diversification of the heterotypic chains provides a robust chemical platform to reframe the understanding of how the ubiquitin codes are regulated from the viewpoint of the branch structure for the precise control of cell functions, which has not been deciphered solely on the basis of the linkage types.

Expanding the VEXAS diagnostic workup: the role of peripheral blood cytological analysis

VEXAS syndrome is a newly described autoinflammatory entity characterized by somatic mutations in the UBA1 X-linked gene in hematopoietic progenitor cells. Several studies have demonstrated that the presence of vacuoles in progenitor cells from bone marrow aspirates is a hallmark finding for this syndrome. Therefore, this study aimed to characterize leukocytes from VEXAS patients versus patients with ANCA-associated vasculitis (AAV), familial Mediterranean fever (FMF), and healthy donors (HD) to define a specific cytological pattern that can support VEXAS diagnosis. Twelve VEXAS patients were included in the study. Blood samples from FMF (n = 16), AAV (n = 16) and HDs (n = 20) acted as controls. May-Grünwald Giemsa (MGG) staining was used for studying cellular morphology, including cytoplasm, granules, and vacuoles and to perform a cytogenic evaluation of leucocytes. Plasma IL-1β, IL-1α, TNFα, IL-18 and IL-8 were measured using ELISA assay. The cytological analysis from blood smears confirmed the presence of immature neutrophils in VEXAS patients. We found a greater number of vacuoles in VEXAS patients vs. FMF, AAV and HD. Micronuclei (MNi) and cell death rate were higher in VEXAS patients vs. HD. Cell death correlated with IL-1β and IL-8 levels. MNi were positively associated with IL-8 and IL-1β levels, and with the percentage of immature neutrophils and vacuoles. In conclusion, our findings suggested that cytological test may be supportive for VEXAS diagnosis, despite genetical analysis is mandatory for confirming the disease. Finally, we identified several cytological hallmarks that may distinguish the VEXAS "cytotype" not only from HD but also from other inflammatory diseases.

ITCH inhibits alkaliptosis in human pancreatic cancer cells through YAP1-dependent SLC16A1 activation

Alkaliptosis is a type of pH-dependent cell death and plays an emerging role in tumor suppression. However, the key modulation mechanism of alkaliptosis remains largely unknown. In particular, the nucleus, as the centre of genetic and metabolic regulation, is crucial for the regulation of cellular life. It is not known whether nuclear proteins are involved in the regulation of alkaliptosis. Here, we isolated nuclear proteins to perform a proteomics that identified itchy E3 ubiquitin protein ligase (ITCH) as a natural inhibitor of alkaliptosis in human pancreatic ductal adenocarcinoma (PDAC) cells. The downregulation of ITCH protein is associated with the induction of alkaliptosis in three human PDAC cell lines (SW1990, MiaPaCa2, and PANC1). Functionally, increasing ITCH expression reduces JTC801-induced growth inhibition and cell death. In contrast, knocking down ITCH using specific shRNA increases JTC801-induced cell growth inhibition in the short or long term, resulting in increased cell death. Mechanistically, JTC801-induced ITCH inhibition blocks large tumor suppressor kinase 1 (LATS1) ubiquitination, which in turn suppresses Yes1 associated transcriptional regulator (YAP1)-dependent the transcriptional activation of solute carrier family 16 member 1 (SLC16A1), a proton-linked monocarboxylate transporter that inhibits JTC801-induced alkaliptosis. Additionally, decreased expression of ITCH is associated with longer survival times in patients with PDAC. Collectively, our results establish an ITCH-dependent pathway that regulates alkaliptotic sensitivity in PDAC cells and deepen the understanding of alkaliptosis in targeted therapy.

NUP37 accumulation mediated by TRIM28 enhances lipid synthesis to accelerate HCC progression

Elevated intracellular lipid synthesis is important for hepatocellular carcinoma (HCC) progression. Our study aimed to identify the role of nucleoporin 37 (NUP37) in lipid synthesis and HCC progression. The expression of NUP37 was significantly upregulated in HCC and associated with a poor prognosis. NUP37 silencing suppressed lipid synthesis, proliferation, migration, and invasion of HCC cells in vitro, and restrained tumor growth in xenograft mouse models in vivo. Next, we found the high expression of NUP37 in HCC was related to post-translational modifications. Tripartite motif-containing 28 (TRIM28) was identified as an interacting protein of NUP37 and upregulated its protein level. The subsequent analysis revealed that TRIM28-mediated SUMOylation of NUP37 at Lys114/118/246 inhibited K27-linked polyubiquitination of NUP37, which is one reason for its high expression level in HCC. In conclusion, TRIM28 SUMOylates NUP37 to prevent its ubiquitination and proteasomal degradation, increasing the stability of the NUP37 protein, thereby promoting lipid synthesis and the progression of HCC.

Tumor-repopulating cells evade ferroptosis via PCK2-dependent phospholipid remodeling

Whether stem-cell-like cancer cells avert ferroptosis to mediate therapy resistance remains unclear. In this study, using a soft fibrin gel culture system, we found that tumor-repopulating cells (TRCs) with stem-cell-like cancer cell characteristics resist chemotherapy and radiotherapy by decreasing ferroptosis sensitivity. Mechanistically, through quantitative mass spectrometry and lipidomic analysis, we determined that mitochondria metabolic kinase PCK2 phosphorylates and activates ACSL4 to drive ferroptosis-associated phospholipid remodeling. TRCs downregulate the PCK2 expression to confer themselves on a structural ferroptosis-resistant state. Notably, in addition to confirming the role of PCK2-pACSL4(T679) in multiple preclinical models, we discovered that higher PCK2 and pACSL4(T679) levels are correlated with better response to chemotherapy and radiotherapy as well as lower distant metastasis in nasopharyngeal carcinoma cohorts.

The cuproptosis-related gene UBE2D2 functions as an immunotherapeutic and prognostic biomarker in pan-cancer

BACKGROUND

Cuproptosis, as a unique modality of regulated cell death, requires the involvement of ubiquitin-binding enzyme UBE2D2. However, the prognostic and immunotherapeutic values of UBE2D2 in pan-cancer remain largely unknown.

METHODS

Using UCSC Xena, TIMER, Clinical Proteomic Tumor Analysis Consortium (CPTAC), and Human Protein Atlas (HPA) databases, we aimed to explore the differential expression pattern of UBE2D2 across multiple cancer types and to evaluate its association with patient prognosis, clinical features, and genetic variations. The association between UBE2D2 and immunotherapy response was assessed by gene set enrichment analysis, tumor microenvironment, immune gene co-expression and drug half maximal inhibitory concentration (IC50) analysis.

RESULTS

The mRNA and protein levels of UBE2D2 were markedly elevated in most cancer types, and UBE2D2 exhibited prognostic significance in liver hepatocellular carcinoma (LIHC), kidney chromophobe (KICH), uveal melanomas (UVM), cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC), and kidney renal papillary cell carcinoma (KIRP). UBE2D2 expression was correlated with clinical features, tumor mutation burden, microsatellite instability, and anti-tumor drug resistance in several tumor types. Gene enrichment analysis showed that UBE2D2 was significantly associated with immune-related pathways. The expression level of UBE2D2 was correlated with immune cell infiltration, including CD4 + T cells、Macrophages M2、CD8 + T cells in pan-cancer. PDCD1, CD274 and CTLA4 expression levels were positively correlated with UBE2D2 level in multiple cancers.

CONCLUSIONS

We comprehensively investigated the potential value of UBE2D2 as a prognostic and immunotherapeutic predictor for pan-cancer, providing a novel insight for cancer immunotherapy.

LncOCMRL1 promotes oral squamous cell carcinoma growth and metastasis via the RRM2/EMT pathway

BACKGROUND

Long noncoding RNAs (lncRNAs) are widely involved in cancer development and progression, but the functions of most lncRNAs have not yet been elucidated. Metastasis is the main factor restricting the therapeutic outcomes of various cancer types, including oral squamous cell carcinoma (OSCC). Therefore, exploring the key lncRNAs that regulate OSCC metastasis and elucidating their molecular mechanisms will facilitate the development of new strategies for effective OSCC therapy.

METHODS

We analyzed the lncRNA expression profiles of tumor tissues from OSCC patients with and without cervical lymph node metastasis, and OSCC cell lines. We revealed high expression of oral squamous cell carcinoma metastasis-related lncRNA 1 (lncOCMRL1) in OSCC patient tumor tissues with lymph node metastasis and highly metastatic OSCC cell lines. The effects of lncOCMRL1 knockdown on the invasion, migration and proliferation abilities of OSCC cells were explored through qRT-PCR, Transwell, colony formation, and cell proliferation experiments. The mechanism by which lncOCMRL1 promotes OSCC metastasis and proliferation was explored through RNA pull-down, silver staining, mass spectrometry, RIP, and WB experiments. To increase its translational potential, we developed a reduction-responsive nanodelivery system to deliver siRNA for antitumor therapy.

RESULTS

We determined that lncOCMRL1 is highly expressed in OSCC metastatic tumor tissues and cells. Functional studies have shown that high lncOCMRL1 expression can promote the growth and metastasis of OSCC cells both in vivo and in vitro. Mechanistically, lncOCMRL1 could induce epithelial-mesenchymal transition (EMT) via the suppression of RRM2 ubiquitination and thereby promote the proliferation, invasion, and migration of OSCC cells. We further constructed reduction-responsive nanoparticles (NPs) for the systemic delivery of siRNAs targeting lncOCMRL1 and demonstrated their high efficacy in silencing lncOCMRL1 expression in vivo and significantly inhibited OSCC tumor growth and metastasis.

CONCLUSIONS

Our results suggest that lncOCMRL1 is a reliable target for blocking lymph node metastasis in OSCC.

KIFC1 depends on TRIM37-mediated ubiquitination of PLK4 to promote centrosome amplification in endometrial cancer

Endometrial cancer (EC), as one of the most common cancers, severely threatens female reproductive health. Our previous study has shown that Kinesin family member C1 (KIFC1) played crucial roles in the progression of EC. In addition, abnormal centrosome amplification, which was reported to be partially regulated by KIFC1, usually occurred in different cancers. However, whether KIFC1 promoted EC through centrosome amplification and the potential mechanism remain to be revealed. The present study demonstrated that overexpressed KIFC1, which exhibited a worse prognosis, had a positive correlation with an increased number of centrosomes in human EC samples. In addition, KIFC1 overexpression in EC cells prompted centrosome amplification, chromosomal instability, and cell cycle progression. Moreover, we demonstrated that KIFC1 inhibited E3 ubiquitin-protein ligase TRIM37 to maintain the stability of PLK4 by reducing its ubiquitination degradation, and finally promoting centrosome amplification and EC progression in vitro. Finally, the contributing role of KIFC1 and the inhibitory effect of TRIM37 on EC development and metastasis was verified in a nude mouse xenograft model. Our study elucidated that KIFC1 depends on TRIM37-mediated reduced ubiquitination degradation of PLK4 to promote centrosome amplification and EC progression, thus providing a potential prognostic marker and promising therapeutic target for EC in the future.

HECTD2 as a target for veratric acid in the regulation of ferroptosis in renal cell carcinoma

Function of HECTD2 in renal cell carcinoma malignant progression is undefined. Molecular mechanism behind anti-cancer effects of veratric acid (VA) from traditional Chinese medicine (TCM) is underexplored. The Cancer Genome Atlas was leveraged to study HECTD2 expression in renal cell carcinoma and its relationship with histological grading. Kaplan-Meier survival analysis was performed. HECTD2 expression was detected in cancer cells and tissues via qRT-PCR and immunohistochemistry. GPX4 and SLC7A11 expression in tumor samples with high or low HECTD2 expression was examined by immunohistochemistry, cell viability by CCK8, cell proliferation by colony formation assay, lipid ROS and mitochondrial superoxide levels by flow cytometry, Fe2+ and MDA content by assay kits, and GPX4 and SLC7A11 proteins by western blot. SeeSAR software screened TCM small molecule compounds with highest affinity to HECTD2, confirmed with cellular thermal shift assay. VA IC50 was measured by CCK8. Xenograft model was developed and treated with VA. Tumor size and weight were monitored, with immunohistochemistry to detect HECTD2 expression in tumors and assess ferroptosis-related markers. HECTD2 was overexpressed in tumor tissues and cells, which positively correlated with histological grading. HECTD2 depletion inhibited cell vitality and proliferation, raised intracellular lipid ROS, mitochondrial superoxide, Fe2+, and MDA. HECTD2 was a target with highest VA affinity. In vitro and vivo experiments concurred that VA treatment hindered malignancy of renal cell carcinoma and enhanced its susceptibility to ferroptosis. HECTD2 supports ferroptosis resistance in renal cell carcinoma, but VA, through its targeting of HECTD2, initiates ferroptosis, showcasing its anti-cancer efficacy.

Discovery of Novel [1,2,4]Triazolo[1,5-a]pyrimidine Derivatives as Novel Potent S-Phase Kinase-Associated Protein 2 (SKP2) Inhibitors for the Treatment of Cancer

Skp1-CUL1-ROC1-F-box E3 ubiquitin ligases' main component S-phase kinase-associated protein 2 (Skp2) is responsible for specifically recognizing ubiquitination-modified substrates to be degraded such as p27 and p21 in the case of binding with adaptor protein Cks1. Pharmacological inhibition of Skp2 has exhibited promising antitumor activity. Herein, we present the design and optimization of a series of [1,2,4]triazolo[1,5-a]pyrimidine-based small molecules targeting Skp2. Among them, E35 demonstrated excellent inhibitory activities against the binding of Skp2-Cks1. In addition, compound E35 significantly inhibited colony formation and migration, as well as arrested the cell cycle at the S-phase. Mechanistically, compound E35 markedly decreased the expression of Skp2, as well as increased the expression of its substrates p21 and p27. Furthermore, compound E35 showed an obvious inhibitory effect on MGC-803 xenograft mice without obvious toxicity. All of these results suggest that compound E35 might be a valuable lead compound for antitumor agents targeting Skp2.

E3 ubiquitin ligase ANKIB1 attenuates antiviral immune responses by promoting K48-linked polyubiquitination of MAVS

Upon sensing cytosolic viral RNA, retinoic acid-inducible gene-I-like receptors (RLRs) interact with mitochondrial antiviral signaling proteins (MAVSs) to activate IRF3 and nuclear factor κB (NF-κB) signaling, initiating innate immune responses. Thus, RLR activation plays a vital role in the removal of invasive RNA viruses while maintaining immune homeostasis. However, inadequate or excessive activation of immunity can cause harm and can even lead to lethal consequences. In this study, we identify an E3 ligase, ankyrin repeat and IBR domain containing 1 (ANKIB1), which suppresses RLR signaling via MAVS. ANKIB1 binds to MAVS to enhance K48-linked polyubiquitination with K311R, causing proteasomal degradation of MAVS. Deficiency of ANKIB1 significantly increases the RLR-mediated production of type I interferon (IFN) along with pro-inflammatory factors. Consequently, ANKIB1 deficiency remarkably increases antiviral immunity and decreases viral replication in vivo. Therefore, we reveal that ANKIB1 restricts RLR-induced innate immune activation, indicating its potential role as a therapeutic target for viral infections.

Molecular glue-mediated targeted protein degradation: A novel strategy in small-molecule drug development

Small-molecule drugs are effective and thus most widely used. However, their applications are limited by their reliance on active high-affinity binding sites, restricting their target options. A breakthrough approach involves molecular glues, a novel class of small-molecule compounds capable of inducing protein-protein interactions (PPIs). This opens avenues to target conventionally undruggable proteins, overcoming limitations seen in conventional small-molecule drugs. Molecular glues play a key role in targeted protein degradation (TPD) techniques, including ubiquitin-proteasome system-based approaches such as proteolysis targeting chimeras (PROTACs) and molecular glue degraders and recently emergent lysosome system-based techniques like molecular degraders of extracellular proteins through the asialoglycoprotein receptors (MoDE-As) and macroautophagy degradation targeting chimeras (MADTACs). These techniques enable an innovative targeted degradation strategy for prolonged inhibition of pathology-associated proteins. This review provides an overview of them, emphasizing the clinical potential of molecular glues and guiding the development of molecular-glue-mediated TPD techniques.

Glucose metabolism in glioma: an emerging sight with ncRNAs

Glioma is a primary brain tumor that grows quickly, has an unfavorable prognosis, and can spread intracerebrally. Glioma cells rely on glucose as the major energy source, and glycolysis plays a critical role in tumorigenesis and progression. Substrate utilization shifts throughout glioma progression to facilitate energy generation and biomass accumulation. This metabolic reprogramming promotes glioma cell proliferation and metastasis and ultimately decreases the efficacy of conventional treatments. Non-coding RNAs (ncRNAs) are involved in several glucose metabolism pathways during tumor initiation and progression. These RNAs influence cell viability and glucose metabolism by modulating the expression of key genes of the glycolytic pathway. They can directly or indirectly affect glycolysis in glioma cells by influencing the transcription and post-transcriptional regulation of oncogenes and suppressor genes. In this review, we discussed the role of ncRNAs in the metabolic reprogramming of glioma cells and tumor microenvironments and their abnormal expression in the glucometabolic pathway in glioma. In addition, we consolidated the existing theoretical knowledge to facilitate the use of this emerging class of biomarkers as biological indicators and potential therapeutic targets for glioma.

Knocking out USP7 attenuates cardiac fibrosis and endothelial-to-mesenchymal transition by destabilizing SMAD3 in mice with heart failure with preserved ejection fraction

Background: Heart failure with preserved ejection fraction (HFpEF) is a predominant type of heart failure. Exploring new pathogenesis and identifying potential novel therapeutic targets for HFpEF is of paramount importance. Methods: HFpEF mouse model was established by the "Multiple-hit" strategy, in that 18- to 22-month-old female C57B6/J mice fed with a high-fat diet were further challenged with chronic infusion of Angiotensin II. RNA sequencing analysis showed that USP7 was significantly increased in the heart of HFpEF mice. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis, in conjunction with co-immunoprecipitation (Co-IP) techniques, identified expression of SMAD3, the key molecule of endothelial-to-mesenchymal transition (EndMT), was also significantly elevated. USP7 endothelium-specific knockout mice was generated to investigate the involvement of USP7 in HFpEF. The biological significance of the interaction between USP7 and SMAD3 was further explored. Results: USP7 promotes EndMT and cardiac fibrosis by binding to SMAD3 directly via its UBL (Ubiquitin-like) domain and cysteine at position 223 of USP7, leading SMAD3 deubiquitination to maintain the stability of SMAD3 by removing the K63 ubiquitin chain and preventing the degradation of SMAD3 by proteasomal process. USP7 also promotes SMAD3 phosphorylation and nuclear translocation, thereby aggravating EndMT and cardiac fibrosis. Endothelium-specific USP7 knockout led to improvement of HFpEF phenotypes and reduction of cardiac fibrosis. Overexpression of SMAD3 in endothelium-specific knockout HFpEF mice reversed the protective effects of USP7 knockout in this HFpEF mouse model. Conclusion: Our results indicated that USP7 is one of the key pathogenic molecules of HFpEF, and knocking out USP7 could attenuate HFpEF injury by promoting the degradation of SMAD3. USP7 and SMAD3 inhibition might be potential therapeutic options for HFpEF.

RNF31-mediated IKKα ubiquitination aggravates inflammation and intestinal injury through regulating NF-κB activation in human and mouse neonates

AIMS

Neonatal necrotizing enterocolitis (NEC) is a leading cause of intestine inflammatory disease, and macrophage is significantly activated during NEC development. Posttranslational modifications (PTMs) of proteins, particularly ubiquitination, play critical roles in immune response. This study aimed to investigate the effects of ubiquitin-modified proteins on macrophage activation and NEC, and discover novel NEC-related inflammatory proteins.

MATERIALS AND METHODS

Proteomic and ubiquitin proteomic analyses of intestinal macrophages in NEC/healthy mouse pups were carried out. In vitro macrophage inflammation model and in vivo NEC mouse model, as well as clinical human samples were used for further verification the inhibitor of nuclear factor-κB kinase α (IKKα) ubiquitination on NEC development through Western blot, immunofluorescence, quantitative real-time polymerase chain reaction (qRT-PCR) and flow cytometry.

KEY FINDINGS

We report here that IKKα was a new ubiquitin-modified protein during NEC through ubiquitin proteomics, and RING finger protein 31 (RNF31) acted as an E3 ligase to be involved in IKKα degradation. Inhibition of IKKα ubiquitination and degradation with siRNF31 or proteasome inhibitor decreased nuclear factor-κB (NF-κB) activation, thereby decreasing the expression of pro-inflammatory factors and M1 macrophage polarization, resulting in reliving the severity of NEC.

SIGNIFICANCE

Our study suggests the activation of RNF31-IKKα-NF-κB axis triggering NEC development and suppressing RNF31-mediated IKKα degradation may be therapeutic strategies to be developed for NEC treatment.

eIF6 Promotes Gastric Cancer Proliferation and Invasion by Regulating Cell Cycle

OBJECTIVE

To investigate the role and function of eIF6 in gastric cancer (GC).

METHODS

The expression level of eIF6 in GC tissues and normal tissues was detected in different high-throughput sequencing cohorts. Survival analysis, gene differential analysis, and enrichment analysis were performed in the TCGA cohort. Biological networks centered on eIF6 were constructed through two different databases. Immunohistochemistry (IHC) and Western blot were used to detect protein expression of eIF6, and qRT-PCR was used to detect eIF6 mRNA expression. The correlation between the expression of eIF6 in GC tissues and clinicopathological parameters of GC was analyzed. siRNA knockout of eIF6 was used to study the proliferation, migration, and invasion. The effects of eIF6 on cell cycle and Cyclin B1 were detected by flow cytometry and Western blot.

RESULTS

eIF6 was significantly overexpressed in GC tissues and predicted poor prognosis. In addition, 113 differentially expressed genes were detected in cancer-related biological pathways and functions by differential analysis. Biological networks revealed interactions of genes and proteins with eIF6. The expression intensity of eIF6 in cancer tissues was higher than that in adjacent tissues (P = 0.0001), confirming the up-regulation of eIF6 expression in GC tissues. The expression level of eIF6 was statistically significant with pTNM stage (P = 0.006). siRNA knockout of eIF6 significantly reduced the proliferation, colony formation, migration, and invasion ability of GC cells. Silencing of eIF6 also inhibited the cell cycle of GC cells in G2/M phase and decreased the expression level of CyclinB1.

CONCLUSION

Our study suggests that eIF6 is up-regulated in GC and may promote the proliferation, migration, and invasion of GC by regulating cell cycle.

The Role of Pyruvate Kinase M2 Posttranslational Modification in the Occurrence and Development of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the deadly malignant tumors that directly leads to the death of nearly one million people worldwide every year, causing a serious burden on society. In the presence of sufficient oxygen, HCC cells rapidly generate energy through aerobic glycolysis, which promotes tumor cell proliferation, immune evasion, metastasis, angiogenesis, and drug resistance. Pyruvate kinase M2 (PKM2) is a key rate-limiting enzyme in glycolysis. In recent years, studies have found that PKM2 not only exerts pyruvate kinase activity in the process of glucose metabolism, but also exerts protein kinase activity in non-metabolic pathways to affect tumor cell processes, and its activity is flexibly regulated by various posttranslational modifications such as acetylation, phosphorylation, lactylation, ubiquitination, SUMOylation, and so forth. This review summarizes the role of posttranslational modifications of PKM2-related sites in the development of HCC.

Identification and validation of ferroptosis-related hub genes and immune infiltration in liver ischemia-reperfusion injury

Ischemia-reperfusion injury (IRI) is a cumulation of pathophysiological processes that involves cell and organelle damage upon blood flow constraint and subsequent restoration. However, studies on overall immune infiltration and ferroptosis in liver ischemia-reperfusion injury (LIRI) are limited. This study explored immune cell infiltration and ferroptosis in LIRI using bioinformatics and experimental validation. The GSE151648 dataset, including 40 matched pairs of pre- and post- transplant liver samples was downloaded for bioinformatic analysis. Eleven hub genes were identified by overlapping differentially expressed genes (DEGs), iron genes, and genes identified through weighted gene co-expression network analysis (WGCNA). Subsequently, the pathway enrichment, transcription factor-target, microRNA-mRNA and protein-protein interaction networks were investigated. The diagnostic model was established by logistic regression, which was validated in the GSE23649 and GSE100155 datasets and verified using cytological experiments. Moreover, several drugs targeting these genes were found in DrugBank, providing a more effective treatment for LIRI. In addition, the expression of 11 hub genes was validated using quantitative real-time polymerase chain reaction (qRT-PCR) in liver transplantation samples and animal models. The expression of the 11 hub genes increased in LIRI compared with the control. Five genes were significantly enriched in six biological process terms, six genes showed high enrichment for LIRI-related signaling pathways. There were 56 relevant transcriptional factors and two central modules in the protein-protein interaction network. Further immune infiltration analysis indicated that immune cells including neutrophils and natural killer cells were differentially accumulated in the pre- and post-transplant groups, and this was accompanied by changes in immune-related factors. Finally, 10 targeted drugs were screened. Through bioinformatics and further experimental verification, we identified hub genes related to ferroptosis that could be used as potential targets to alleviate LIRI.

SP1 MEDIATES OGD/R-INDUCED CARDIOMYOCYTE INJURY VIA ENHANCING THE TRANSCRIPTION OF USP46

ABSTRACT

Background: One of the mechanisms responsible for the high mortality rate of acute myocardial infarction is myocardial ischemia-reperfusion injury (MI-RI). The present study focused on the role and regulatory mechanisms of specificity protein 1 (SP1) and ubiquitin-specific protease 46 (USP46) in oxygen-glucose deprivation/reperfusion (OGD/R)-induced cardiomyocyte injury. Methods: OGD/R was used to treat cardiomyocytes AC16 to mimic ischemia-reperfusion in vitro . Cell viability, proliferation, and apoptosis were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, 5-ethynyl-2'-deoxyuridine, and flow cytometry assays. Enzyme-linked immunosorbent assays analyzed the concentrations of TNF-α and IL-1β. Several protein levels were analyzed by western blotting. The levels of iron (Fe 2+ ), reactive oxygen species, malondialdehyde, and the activities of superoxide dismutase were analyzed by commercial kits. Chromatin immunoprecipitation and dual-luciferase report assays assessed the relationship between USP46 and SP1. Results: USP46 and SP1 were upregulated in serum from MI patients and they had a positive correlation. OGD/R stimulation suppressed cardiomyocyte viability and proliferation, as well as induced cardiomyocyte inflammation, oxidative stress (OxS) injury, apoptosis, and ferroptosis, but these effects were impaired by USP46 or SP1 knockdown. SP1 could enhance the transcription of USP46, and USP46 overexpression reversed SP1 silencing-mediated effects on OGD/R-induced cardiomyocytes. SP1 mediated the AMPK signaling via USP46 . Conclusion: SP1 mediated OGD/R-induced cardiomyocyte inflammation, OxS injury, apoptosis, and ferroptosis by inactivating the AMPK signaling via enhancing the transcription of USP46.

Ubiquitination of angiotensin-converting enzyme 2 contributes to the development of pulmonary arterial hypertension mediated by neural precursor cell-expressed developmentally down-regulated gene 4-Like

OBJECTIVES

In this study, we investigated whether neural precursor cell-expressed developmentally down-regulated gene 4-like (NEDD4L) is the E3 enzyme of angiotensin-converting enzyme 2 (ACE2) and whether NEDD4L degrades ACE2 via ubiquitination, leading to the progression of pulmonary arterial hypertension (PAH).

METHODS

Bioinformatic analyses were used to explore the E3 ligase that ubiquitinates ACE2. Cultured pulmonary arterial smooth muscle cells (PASMCs) and specimens from patients with PAH were used to investigate the crosstalk between NEDD4L and ACE2 and its ubiquitination in the context of PAH.

RESULTS

The inhibition of ubiquitination attenuated hypoxia-induced proliferation of PASMCs. The levels of NEDD4L were increased, and those of ACE2 were decreased in lung tissues from patients with PAH and in PASMCs. NEDD4L, the E3 ligase of ACE2, inhibited the expression of ACE2 in PASMCs, possibly through ubiquitination-mediated degradation. PAH was associated with upregulation of NEDD4L expression and downregulation of ACE2 expression.

CONCLUSIONS

NEDD4L, the E3 ubiquitination enzyme of ACE2, promotes the proliferation of PASMCs, ultimately leading to PAH.

OTU deubiquitinase, ubiquitin aldehyde binding 2 (OTUB2) modulates the stemness feature, chemoresistance, and epithelial-mesenchymal transition of colon cancer via regulating GINS complex subunit 1 (GINS1) expression

BACKGROUND

Colon cancer is one of the most prevalent tumors in the digestive tract, and its stemness feature significantly contribute to chemoresistance, promote the epithelial-mesenchymal transition (EMT) process, and ultimately lead to tumor metastasis. Therefore, it is imperative for researchers to elucidate the molecular mechanisms underlying the enhancement of stemness feature, chemoresistance, and EMT in colon cancer.

METHODS

Sphere-formation and western blotting assays were conducted to assess the stemness feature. Edu, flow cytometry, and cell viability assays were employed to evaluate the chemoresistance. Immunofluorescence and western blotting assays were utilized to detect EMT. Immunoprecipitation, ubiquitination, agarose gel electrophoresis, chromatin immunoprecipitation followed by quantitative PCR (chip-qPCR), and dual luciferase reporter gene assays were employed for mechanistic investigations.

RESULTS

We demonstrated a markedly higher expression level of OTUB2 in colon cancer tissues compared to adjacent tissues. Furthermore, elevated OTUB2 expression was closely associated with poor prognosis and distant tumor metastasis. Functional experiments revealed that knockdown of OTUB2 attenuated stemness feature of colon cancer, enhanced its sensitivity to oxaliplatin, inhibited its EMT process, ultimately reduced the ability of tumor metastasis. Conversely, overexpression of OTUB2 exerted opposite effects. Mechanistically, we identified OTUB2 as a deubiquitinase for SP1 protein which bound specifically to SP1 protein, thereby inhibiting K48 ubiquitination of SP1 protein. The SP1 protein functioned as a transcription factor for the GINS1, exerting its regulatory effect by binding to the 1822-1830 region of the GINS1 promoter and enhancing its transcriptional activity. Ultimately, alterations in GINS1 expression directly regulated stemness feature, chemosensitivity, and EMT progression in colon cancer.

CONCLUSION

Collectively, the OTUB2/SP1/GINS1 axis played a pivotal role in driving stemness feature, chemoresistance, and EMT in colon cancer. These results shed new light on understanding chemoresistance and metastasis mechanisms involved in colon cancer.

Connecting Protein Millisecond Conformational Dynamics to Protein Thermal Stability

The stability of protein folded states is crucial for its function, yet the relationship with the protein sequence remains poorly understood. Prior studies have focused on the amino acid composition and thermodynamic couplings within a single folded conformation, overlooking the potential contribution of protein dynamics. Here, we address this gap by systematically analyzing the impact of alanine mutations in the C-terminal β-strand (β5) of ubiquitin, a model protein exhibiting millisecond timescale interconversion between two conformational states differing in the β5 position. Our findings unveil a negative correlation between millisecond dynamics and thermal stability, with alanine substitutions at seemingly flexible C-terminal residues significantly enhancing thermostability. Integrating spectroscopic and computational approaches, we demonstrate that the thermally unfolded state retains a substantial secondary structure but lacks β5 engagement, recapitulating the transition state for millisecond dynamics. Thus, alanine mutations that modulate the stabilities of the folded states with respect to the partially unfolded state impact both the dynamics and stability. Our findings underscore the importance of conformational dynamics with implications for protein engineering and design.

The Role of Deubiquitinating Enzymes in Primary Bone Cancer

Bone is a living, intricate, and dynamic tissue providing locomotion and protection of the body. It also performs hematopoiesis and mineral homeostasis. Osteosarcoma (OS), Ewing sarcoma (ES), and chondrosarcoma (CS) are primary bone cancers. OS and ES mostly develop in younger individuals, and CS generally develops in adults. Ubiquitination regulates numerous cellular processes. The deubiquitinating enzymes (DUBs) detach the ubiquitin molecules from the ubiquitin labeled substrate, altering ubiquitinated protein functions and regulating protein stability via various signaling pathways. Protein homeostasis and bone remodeling are both crucially influenced by the UPS. Recently, there have been several reports on DUBs involved in bone homeostasis and various bone disorders through the regulation of osteoblasts and osteoclasts via NF-κB, Wnt/β-catenin, TRAF6, TGFβ, ERK1/2, and PI3K/Akt pathways. However, DUBs regulating function in bone homeostasis is still in its infancy. Here, we summarized several recent identifications on DUBs, with a focus on their role in bone cancer progression. Therefore, the study attempts to summarize association with the expression level of DUBs as key factors driving bone cancers and also provide new insights on DUBs as key pharmacologic targets for bone cancer therapeutics.

Post-translational modifications in sepsis-induced organ dysfunction: mechanisms and implications

As a grave and highly lethal clinical challenge, sepsis, along with its consequent multiorgan dysfunction, affects millions of people worldwide. Sepsis is a complex syndrome caused by a dysregulated host response to infection, leading to fatal organ dysfunction. An increasing body of evidence suggests that the pathogenesis of sepsis is both intricate and rapid and involves various cellular responses and signal transductions mediated by post-translational modifications (PTMs). Hence, a comprehensive understanding of the mechanisms and functions of PTMs within regulatory networks is imperative for understanding the pathological processes, diagnosis, progression, and treatment of sepsis. In this review, we provide an exhaustive and comprehensive summary of the relationship between PTMs and sepsis-induced organ dysfunction. Furthermore, we explored the potential applications of PTMs in the treatment of sepsis, offering a forward-looking perspective on the understanding of infectious diseases.

FBXO32 Stimulates Protein Synthesis to Drive Pancreatic Cancer Progression and Metastasis

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer-related death worldwide, primarily due to its rapid progression. The current treatment options for PDAC are limited, and a better understanding of the underlying mechanisms responsible for PDAC progression is required to identify improved therapeutic strategies. In this study, we identified FBXO32 as an oncogenic driver in PDAC. FBXO32 was aberrantly upregulated in PDAC, and high FBXO32 expression was significantly associated with an unfavorable prognosis in patients with PDAC. FRG1 deficiency promoted FBXO32 upregulation in PDAC. FBXO32 promoted cell migration and invasion in vitro and tumor growth and metastasis in vivo. Mechanistically, FBXO32 directly interacted with eEF1A1 and promoted its polyubiquitination at the K273 site, leading to enhanced activity of eEF1A1 and increased protein synthesis in PDAC cells. Moreover, FBXO32-catalyzed eEF1A1 ubiquitination boosted the translation of ITGB5 mRNA and activated focal adhesion kinase (FAK) signaling, thereby facilitating focal adhesion assembly and driving PDAC progression. Importantly, interfering with the FBXO32-eEF1A1 axis or pharmaceutical inhibition of FAK by defactinib, an FDA-approved FAK inhibitor, substantially inhibited PDAC growth and metastasis driven by aberrantly activated FBXO32-eEF1A1 signaling. Overall, this study uncovers a mechanism by which PDAC cells rely on FBXO32-mediated eEF1A1 activation to drive progression and metastasis. FBXO32 may serve as a promising biomarker for selecting eligible patients with PDAC for treatment with defactinib. Significance: FBXO32 upregulation in pancreatic cancer induced by FRG1 deficiency increases eEF1A1 activity to promote ITGB5 translation and stimulate FAK signaling, driving cancer progression and sensitizing tumors to the FAK inhibitor defactinib.

Construction and validation of a ubiquitination-related prognostic risk score signature in breast cancer

Background

Breast cancer (BC) is a highly common form of cancer that occurs in many parts of the world. However, early -stage BC is curable. Many patients with BC have poor prognostic outcomes owing to ineffective diagnostic and therapeutic tools. The ubiquitination system and associated proteins were found influencing the outcome of individuals with cancer. Therefore, developing a biomarker associated with ubiquitination genes to forecast BC patient outcomes is a feasible strategy.

Objective

The primary goal of this work was to develop a novel risk score signature capable of accurately estimate the future outcome of patients with BC by targeting ubiquitinated genes.

Methods

Univariate Cox regression analysis was conducted utilizing the E1, E2, and E3 ubiquitination-related genes in the GSE20685 dataset. Genes with p < 0.01 were screened again using the Non-negative Matrix Factorization (NMF) algorithm, and the resulting hub genes were composed of a risk score signature. Patients were categorized into two risk groups, and the predictive effect was tested using Kaplan-Meier (KM) and Receiver Operating Characteristic (ROC) curves. This risk score signature was later validated using multiple external datasets, namely TCGA-BRAC, GSE1456, GSE16446, GSE20711, GSE58812 and GSE96058. Immuno-microenvironmental, single-cell, and microbial analyses were also performed.

Results

The selected gene signature comprising six ubiquitination-related genes (ATG5, FBXL20, DTX4, BIRC3, TRIM45, and WDR78) showed good prognostic power in patients with BC. It was validated using multiple externally validated datasets, with KM curves showing significant differences in survival (p < 0.05). The KM curves also demonstrated superior predictive ability compared to traditional clinical indicators. Single-cell analysis revealed that Vd2 gd T cells were less abundantin the low-risk group, whereas patients in the high-risk group lacked myeloid dendritic cells. Tumor microbiological analysis revealed a notable variation in microorganism diversity between the high- and low-risk groups.

Conclusion

This study established an risk score signature consisting of six ubiquitination genes, that can accurately forecast the outcome of patients with BC using multiple datasets. It can provide personalized and targeted assistance to provide the evaluation and therapy of individuals having BC.

Polyphenols alleviate metabolic disorders: the role of ubiquitin-proteasome system

Metabolic disorders include obesity, nonalcoholic fatty liver disease, insulin resistance and type 2 diabetes. It has become a major health issue around the world. Ubiquitin-proteasome system (UPS) is essential for nearly all cellular processes, functions as a primary pathway for intracellular protein degradation. Recent researches indicated that dysfunctions in the UPS may result in the accumulation of toxic proteins, lipotoxicity, oxidative stress, inflammation, and insulin resistance, all of which contribute to the development and progression of metabolic disorders. An increasing body of evidence indicates that specific dietary polyphenols ameliorate metabolic disorders by preventing lipid synthesis and transport, excessive inflammation, hyperglycemia and insulin resistance, and oxidative stress, through regulation of the UPS. This review summarized the latest research progress of natural polyphenols improving metabolic disorders by regulating lipid accumulation, inflammation, oxidative stress, and insulin resistance through the UPS. In addition, the possible mechanisms of UPS-mediated prevention of metabolic disorders are comprehensively proposed. We aim to provide new angle to the development and utilization of polyphenols in improving metabolic disorders.

The role of protein post-translational modifications in prostate cancer

Involving addition of chemical groups or protein units to specific residues of the target protein, post-translational modifications (PTMs) alter the charge, hydrophobicity, and conformation of a protein, which in turn influences protein function, protein-protein interaction, and protein aggregation. These alterations, which include phosphorylation, glycosylation, ubiquitination, methylation, acetylation, lipidation, and lactylation, are significant biological events in the development of cancer, and play vital roles in numerous biological processes. The processes behind essential functions, the screening of clinical illness signs, and the identification of therapeutic targets all depend heavily on further research into the PTMs. This review outlines the influence of several PTM types on prostate cancer (PCa) diagnosis, therapy, and prognosis in an effort to shed fresh light on the molecular causes and progression of the disease.

Rupatadine-inhibited OTUD3 promotes DLBCL progression and immune evasion through deubiquitinating MYL12A and PD-L1

The obstacle to effectively treating Diffuse Large B-cell Lymphoma (DLBCL) lies in the resistance observed toward standard therapies. Identifying therapeutic targets that prove effective for relapsed or refractory patients poses a significant challenge. OTUD3, a deubiquitinase enzyme, is overexpressed in DLBCL tissues. However, its role in DLBCL has not been investigated. Our study has brought to light the multifaceted impact of OTUD3 in DLBCL. Not only does it enhance cell survival through the deubiquitination of MYL12A, but it also induces CD8+ T cell exhaustion within the local environment by deubiquitinating PD-L1. Our findings indicate that the OTUD3 inhibitor, Rupatadine, exerts its influence through competitive binding with OTUD3. This operation diminishes the deubiquitination of both MYL12A and PD-L1 by OTUD3. This research unveils the central and oncogenic role of OTUD3 in DLBCL and highlights the potential clinical application value of the OTUD3 inhibitor, Rupatadine. These findings contribute valuable insights into addressing the challenges of resistant DLBCL cases and offer a promising avenue for further clinical exploration.

CircVPS8 promotes the malignant phenotype and inhibits ferroptosis of glioma stem cells by acting as a scaffold for MKRN1, SOX15 and HNF4A

Exciting breakthroughs have been achieved in the field of glioblastoma with therapeutic interventions targeting specific ferroptosis targets. Nonetheless, the precise mechanisms through which circRNAs regulate the ferroptosis pathway have yet to be fully elucidated. Here we have identified a novel circRNA, circVPS8, which is highly expressed in glioblastoma. Our findings demonstrated that circVPS8 enhances glioma stem cells' viability, proliferation, sphere-forming ability, and stemness. Additionally, it inhibits ferroptosis in GSCs. In vivo, experiments further supported the promotion of glioblastoma growth by circVPS8. Mechanistically, circVPS8 acts as a scaffold, binding to both MKRN1 and SOX15, thus facilitating the ubiquitination of MKRN1 and subsequent degradation of SOX15. Due to competitive binding, the ubiquitination ability of MKRN1 towards HNF4A is reduced, leading to elevated HNF4A expression. Increased HNF4A expression, along with decreased SOX15 expression, synergistically inhibits ferroptosis in glioblastoma. Overall, our study highlights circVPS8 as a promising therapeutic target and provides valuable insights for clinically targeted therapy of glioblastoma.

USP19 Stabilizes TAK1 to Regulate High Glucose/Free Fatty Acid-induced Dysfunction in HK-2 Cells

OBJECTIVE

Obesity-induced kidney injury contributes to the development of diabetic nephropathy (DN). Here, we identified the functions of ubiquitin-specific peptidase 19 (USP19) in HK-2 cells exposed to a combination of high glucose (HG) and free fatty acid (FFA) and determined its association with TGF-beta-activated kinase 1 (TAK1).

METHODS

HK-2 cells were exposed to a combination of HG and FFA. USP19 mRNA expression was detected by quantitative RT-PCR (qRT-PCR), and protein analysis was performed by immunoblotting (IB). Cell growth was assessed by Cell Counting Kit-8 (CCK-8) viability and 5-ethynyl-2'-deoxyuridine (EdU) proliferation assays. Cell cycle distribution and apoptosis were detected by flow cytometry. The USP19/TAK1 interaction and ubiquitinated TAK1 levels were assayed by coimmunoprecipitation (Co-IP) assays and IB.

RESULTS

In HG+FFA-challenged HK-2 cells, USP19 was highly expressed. USP19 knockdown attenuated HG+FFA-triggered growth inhibition and apoptosis promotion in HK-2 cells. Moreover, USP19 knockdown alleviated HG+FFA-mediated PTEN-induced putative kinase 1 (PINK1)/Parkin pathway inactivation and increased mitochondrial reactive oxygen species (ROS) generation in HK-2 cells. Mechanistically, USP19 stabilized the TAK1 protein through deubiquitination. Importantly, increased TAK1 expression reversed the USP19 knockdown-mediated phenotypic changes and PINK1/Parkin pathway activation in HG+FFA-challenged HK-2 cells.

CONCLUSION

The findings revealed that USP19 plays a crucial role in promoting HK-2 cell dysfunction induced by combined stimulation with HG and FFAs by stabilizing TAK1, providing a potential therapeutic strategy for combating DN.

Brain -cyst-driven genes expression in Toxoplasma Gondii Tehran strain: a parasitic-immunogenicity assessment by dint of RNA-Seq

Toxoplasma gondii (T. gondii) is an obligate intracellular parasite of warm-blooded vertebrates. At present, High-throughput RNA sequencing analysis have made it possible to determine the role of effective genes in host immune response. The aim of the present study is to global transcriptome analysis of the brain of mice infected with T. gondii Tehran strain for the first time and also to evaluate the expression of effective genes in the chronic form of infection. RNA was extracted from the samples and the library was prepared and sequenced using the IlluminaNovaSeq 6000 system. After analyzing gene expression changes, the results were confirmed by real-time method. We found 125 genes that were significantly differentially expressed between infected and non-infected samples (p < 0.0005). Gene ontology analysis revealed that the expression of many genes is critical for pathways such as T cell receptor signaling pathway, Natural Killer cell mediated cytotoxicity, Lysosome and Apoptosis of the host. As infection with Tehran strain leads to chronic infection in mice, therefore, we investigated the genes effective in creating the chronic form of Toxoplasma infection. The comparative analysis of genes showed increases in the expression of genes ctla4, ccl4, cd3e, c3, lcn2, gbp5, usp18, cyba, tap1 and samhd1 in the in the infected sample, which highlights their role in causing chronic infection. RNA-seq provides a valuable tool for analyzing host transcriptomes, better understanding the parasite-host interaction, and developing future drug and vaccine targets.

Regulations of m6A and other RNA modifications and their roles in cancer

RNA modification is an essential component of the epitranscriptome, regulating RNA metabolism and cellular functions. Several types of RNA modifications have been identified to date; they include N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), N7-methylguanosine (m7G), N6,2'-O-dimethyladenosine (m6Am), N4-acetylcytidine (ac4C), etc. RNA modifications, mediated by regulators including writers, erasers, and readers, are associated with carcinogenesis, tumor microenvironment, metabolic reprogramming, immunosuppression, immunotherapy, chemotherapy, etc. A novel perspective indicates that regulatory subunits and post-translational modifications (PTMs) are involved in the regulation of writer, eraser, and reader functions in mediating RNA modifications, tumorigenesis, and anticancer therapy. In this review, we summarize the advances made in the knowledge of different RNA modifications (especially m6A) and focus on RNA modification regulators with functions modulated by a series of factors in cancer, including regulatory subunits (proteins, noncoding RNA or peptides encoded by long noncoding RNA) and PTMs (acetylation, SUMOylation, lactylation, phosphorylation, etc.). We also delineate the relationship between RNA modification regulator functions and carcinogenesis or cancer progression. Additionally, inhibitors that target RNA modification regulators for anticancer therapy and their synergistic effect combined with immunotherapy or chemotherapy are discussed.

A Novel Gene Signature Associated with Protein Post-translational Modification to Predict Clinical Outcomes and Therapeutic Responses of Colorectal Cancer

Accumulated evidence highlights the biological significance of diverse protein post-translational modifications (PTMs) in tumorigenicity and progression of colorectal cancer (CRC). In this study, ten PTM patterns (ubiquitination, methylation, phosphorylation, glycosylation, acetylation, SUMOylation, citrullination, neddylation, palmitoylation, and ADP-ribosylation) were analyzed for model construction. A post-translational modification index (PTMI) with a 14-gene signature was established. CRC patients with high PTMI had a worse prognosis after validating in nine independent datasets. By incorporating PTMI with clinical features, a nomogram with excellent predictive performance was constructed. Two molecular subtypes of CRC with obvious difference in survival time were identified by unsupervised clustering. Furthermore, PTMI was related to known immunoregulators and key tumor microenvironment components. Low-PTMI patients responded better to fluorouracil-based chemotherapy and immune checkpoint blockade therapy compared to high-PTMI patients, which was validated in multiple independent datasets. However, patients with high PTMI might be sensitive to bevacizumab. In short, we established a novel PTMI model by comprehensively analyzing diverse post-translational modification patterns, which can accurately predict clinical prognosis and treatment response of CRC patients.

PELI1 overexpression contributes to pancreatic cancer progression through upregulating ubiquitination-mediated INPP5J degradation

Inositol Polyphosphate-5-Phosphatase J (INPP5J), a 5-phosphatase, has been identified as a tumor suppressor in several types of cancer. However, its role in pancreatic cancer (PC) is unknown. We found that the INPP5J expression was markedly lower in PC tissues (n = 50) compared to paired adjacent non-tumor tissues, and the lower INPP5J expression was relevant to a worse prognosis of PC patients. We thus proposed that INPP5J might inhibit PC progression and conducted gain-of- and loss-of-function experiments to test our hypothesis. Our results showed that overexpression of INPP5J inhibited cell proliferation, invasion, migration, and xenografted tumor of PC cells. INPP5J silencing showed the opposite effect. Pellino E3 Ubiquitin Protein Ligase 1 (PELI1) is one of the ubiquitin ligases known to promote ubiquitination of its downstream targets. We found that PELI1 could interact with INPP5J and promote the ubiquitination and degradation of INPP5J. PELI1 overexpression enhanced malignant behaviors of PC cells. However, INPP5J overexpression restored the alterations caused by PELI1 overexpression. In conclusion, the results suggest that the decreased INPP5J expression, caused by PELI1 through ubiquitination, may promote PC progression. The PELI1-INPP5J axis represents a potential therapeutic targetable node for PC.

The Deubiquitinase USP22-Stabilized COL17A1 Promotes Lung Adenocarcinoma Progression

BACKGROUND

Lung adenocarcinoma (LUAD) is a highly aggressive and rapidly fatal malignancy worldwide. Collagen XVII (COL17A1) has been implicated in various protumorigenic processes. However, the functions and mechanisms of COL17A1 in LUAD progression still remain elusive.

METHODS

COL17A1 and ubiquitin-specific protease 22 (USP22) mRNA analysis was performed by quantitative PCR, and their protein levels were detected by immunoblotting and immunohistochemistry. The functional influence was evaluated by determining cell viability, proliferation, apoptosis, invasion, migration, and ferroptosis in vitro, as well as xenograft growth in vivo. Co-immunoprecipitation (Co-IP) and IP experiments were used to examine the USP22/COL17A1 interaction and COL17A1 deubiquitination. Cycloheximide treatment was used to analyze COL17A1 protein stability.

RESULTS

COL17A1 and USP22 were upregulated in human LUAD tissues and cell lines. Functionally, COL17A1 knockdown acted for the suppression of LUAD cell growth, invasion, and migration as well as promotion of cell apoptosis and ferroptosis in vitro. COL17A1 knockdown could diminish the tumorigenicity of LUAD cells in vivo. Mechanistically, USP22 stabilized and upregulated COL17A1 by enhancing the deubiquitination of COL17A1. Additionally, reexpression of COL17A1 could reverse USP22 silencing-induced phenotype changes of LUAD cells in vitro.

CONCLUSION

Our findings demonstrate that USP22-stabilized COL17A1 possesses oncogenic activity in LUAD. We propose that USP22 and COL17A1 would be potential targets for the establishment of therapeutic approaches against LUAD.

Cell death as an architect of adult skin stem cell niches

Our skin provides a physical and immunological barrier against dehydration and environmental insults ranging from microbial attacks, toxins and UV irradiation to wounding. Proper functioning of the skin barrier largely depends on the interplay between keratinocytes- the epithelial cells of the skin- and immune cells. Two spatially distinct populations of keratinocyte stem cells (SCs) maintain the epidermal barrier function and the hair follicle. These SCs are inherently long-lived, but cell death can occur within their niches and impacts their functionality. The default cell death programme in skin is apoptosis, an orderly and non-inflammatory suicide programme. However, recent findings are shedding light on the significance of various modes of regulated necrotic cell death, which are lytic and can provoke inflammation within the local skin environment. While the presence of dying cells was generally regarded as a mere consequence of inflammation, findings in various human dermatological conditions and experimental mouse models of aberrant cell death control demonstrated that cell death programmes in keratinocytes (KCs) can drive skin inflammation and even tumour initiation. When cells die, they need to be removed by phagocytosis and KCs can function as non-professional phagocytes of apoptotic cells with important implications for their SC capacities. It is becoming apparent that in conditions of heightened SC activity, distinct cell death modalities differentially impact the different skin SC populations in their local niches. Here, we describe how regulated cell death modalities functionally affect epidermal SC niches along with their relevance to injury repair, inflammatory skin disorders and cancer.

STAT3-Mediated Ferroptosis is Involved in Sepsis-Associated Acute Respiratory Distress Syndrome

Sepsis-induced acute respiratory distress syndrome (ARDS) poses a grave danger to life, resulting from sepsis-induced multi-organ failure. Although ferroptosis, a form of iron-dependent lipid peroxidative cell death, has been associated with sepsis-induced ARDS, the specific mechanisms are not fully understood. In this study, we utilized WGCNA, PPI, friends analysis, and six machine learning techniques (Lasso, SVM, RFB, XGBoost, AdaBoost, and LightGBM) to pinpoint STAT3 as a potential diagnostic marker. A significant increase in monocyte and neutrophil levels was observed in patients with sepsis-induced ARDS, as revealed by immune infiltration analyses, when compared to controls. Moreover, there was a positive correlation between STAT3 expression and the level of infiltration. Single-cell analysis uncovered a notable disparity in B-cell expression between sepsis and sepsis-induced ARDS. Furthermore, in vitro experiments using LPS-treated human bronchial epithelial cells (BEAS-2B) and THP1 cells demonstrated a significant increase in STAT3 phosphorylation expression. Additionally, the inhibition of STAT3 phosphorylation by Stattic effectively prevented LPS-induced ferroptosis in both BEAS-2B and THP1 cells. This indicates that the activation of STAT3 phosphorylation promotes ferroptosis in human bronchial epithelial cells in response to LPS. In summary, this research has discovered and confirmed STAT3 as a potential biomarker for the diagnosis and treatment of sepsis-induced ARDS.

Phosphorylation of USP27X by PIM2 promotes glycolysis and breast cancer progression via deubiquitylation of MYC

Aberrant cell proliferation is a hallmark of cancer, including breast cancer. Here, we show that USP27X is required for cell proliferation and tumorigenesis in breast cancer. We identify a PIM2-USP27X regulator of MYC signaling axis whose activity is an important contributor to the tumor biology of breast cancer. PIM2 phosphorylates USP27X, and promotes its deubiquitylation activity for MYC, which promotes its protein stability and leads to increase HK2-mediated aerobic glycolysis in breast cancer. Moreover, the PIM2-USP27X-MYC axis is also validated in PIM2-knockout mice. Taken together, these findings show a PIM2-USP27X-MYC signaling axis as a new potential target for breast cancer treatment.

Kumujan B suppresses TNF-α-induced inflammatory response and alleviates experimental colitis in mice

Treatments of inflammatory bowel disease (IBD) are diverse, but their efficacy is limited, and it is therefore urgent to find better therapies. Controlling mucosal inflammation is a must in IBD drug treatment. The occurrence of anti-tumor necrosis factor α (TNF-α) monoclonal antibodies has provided a safer and more efficacious therapy. However, this kind of treatment still faces failure in the form of loss of response. β-Carboline alkaloids own an anti-inflammatory pharmacological activity. While Kumujan B contains β-carboline, its biological activity remains unknown. In this study, we attempted to determine the anti-inflammatory effects of Kumujan B using both the TNF-α- induced in vitro inflammation and DSS-induced in vivo murine IBD models. Our data show that Kumujan B attenuated the expression of interleukin 1β (IL-1β) and interleukin 6 (IL-6) induced by TNF-α in mouse peritoneal macrophages. Kumujan B suppressed c-Jun N-terminal protein kinases (JNK) signaling, especially c-Jun, for anti-inflammatory response. Furthermore, Kumujan B promoted K11-linked ubiquitination and degradation of c-Jun through the proteasome pathway. In an in vivo study, Kumujan B inhibited the expression of IL-1β, IL-6, and TNF-α and improved the colon barrier function in dextran sulfate sodium salt (DSS)-induced experimental mice colitis. Kumujan B exhibited in vivo and in vitro anti-inflammatory effects, making it a potential therapeutic candidate for treating IBD.

Targeted Protein Fate Modulating Functional Microunits Promotes Intervertebral Fusion

Stable regulation of protein fate is a prerequisite for successful bone tissue repair. As a ubiquitin-specific protease (USP), USP26 can stabilize the protein fate of β-catenin to promote the osteogenic activity of mesenchymal cells (BMSCs) and significantly increased bone regeneration in bone defects in aged mice. However, direct transfection of Usp26 in vivo is inefficient. Therefore, improving the efficient expression of USP26 in target cells is the key to promoting bone tissue repair. Herein, 3D printing combined with microfluidic technology is applied to construct a functional microunit (protein fate regulating functional microunit, denoted as PFFM), which includes GelMA microspheres loaded with BMSCs overexpressing Usp26 and seeded into PCL 3D printing scaffolds. The PFFM provides a microenvironment for BMSCs, significantly promotes adhesion, and ensures cell activity and Usp26 supplementation that stabilizes β-catenin protein significantly facilitates BMSCs to express osteogenic phenotypes. In vivo experiments have shown that PFFM effectively accelerates intervertebral bone fusion. Therefore, PFFM can provide new ideas and alternatives for using USP26 for intervertebral fusion and other hard-to-repair bone defect diseases and is expected to provide clinical translational potential in future treatments.