Inhibition of neddylation represses lipopolysaccharide-induced proinflammatory cytokine production in macrophage cells

Mitoxantrone attenuates lipopolysaccharide-induced acute lung injury via inhibition of NEDD8 activating enzyme

BACKGROUND

Lipopolysaccharide (LPS) triggers the activation of nuclear factor kappa B (NF-κB) by interacting with Toll-like receptor 4 (TLR4), leading to the production of various proinflammatory enzymes and cytokines that are crucial in the development of acute lung injury (ALI). Mitoxantrone (MTX) has been demonstrated to mitigate the inflammatory response caused by LPS; however, its precise function in the context of ALI is not fully comprehended.

PURPOSE

This study aimed to investigate the inhibitory effects and underlying mechanisms of MTX against LPS-induced ALI.

METHODS

ALI was induced in C57BL/6 mice via a single intratracheal administration of LPS (5 mg/kg), followed by an intraperitoneal injection of MTX to evaluate its therapeutic potential. The effects of MTX on lung injury and the progression of inflammation in ALI mice were assessed using a comprehensive range of techniques, including hematoxylin-eosin (H&E) staining, immunohistochemistry (IHC), myeloperoxidase activity measurement, cell enumeration in bronchoalveolar lavage fluid (BALF), Western blotting, and enzyme-linked immunosorbent assay (ELISA). Additionally, IHC, Western blotting, and co-immunoprecipitation were used to elucidate the specific signaling pathways and molecular mechanisms by which MTX exerted its anti-inflammatory effects in ALI mice. Surface plasmon resonance (SPR) and molecular docking were used to examine the target to which MTX binds directly to reduce inflammation. We also established a lung epithelial cell injury model using LPS-treated A549 cells. The polyubiquitination of IκBα and TRAF6 in LPS-induced A549 cells was detected through Western blotting following immunoprecipitation.

RESULTS

In mice with LPS-induced ALI, MTX exhibits anti-inflammatory effects by ameliorating histopathological abnormalities caused by LPS, reducing inflammatory cell infiltration, and decreasing the production of proinflammatory enzymes and cytokines. It has been observed that MTX directly binds to the NEDD8 activating enzyme (NAE), thereby inhibiting the transfer of NEDD8 to the substrates UBC12, Cul1, and Cul5. Consequently, the polyubiquitination of IκBα and TRAF6 is disrupted, leading to the suppression of TAK1 activation by TRAF6. This suppression of TAK1 activity hindered the phosphorylation of IKK and MAPK. By stabilizing IκBα through dephosphorylation via IKK inhibition and preventing polyubiquitination, NF-κB activation is reduced. This cascade of events ultimately leads to a reduction in the production of proinflammatory enzymes and cytokines, effectively mitigating the inflammatory response in ALI. In A549 cells, MTX reduces the LPS-induced K48-linked polyubiquitination of IκBα and K63-linked polyubiquitination of TRAF6. This process can be reversed by the overexpression of NEDD8. Additionally, treatment with MG-132, a proteasome inhibitor, can restore the polyubiquitination of IκBα that was inhibited by MTX.

CONCLUSIONS

These findings confirm the essential role of Cul1/5 neddylation in ALI and suggest that MTX could be a promising therapeutic agent for ALI.

Inhibition of the neddylation E2 enzyme UBE2M in macrophages protects against E. coli-induced sepsis

UBE2M, an essential neddylation E2 enzyme, has been implicated in the pathogenesis of various diseases, including cancers, viral infections, and obesity. However, whether UBE2M is involved in the pathogenesis of bacterial sepsis remains unclear. In an Escherichia coli (E. coli)-induced sepsis mouse model, increased UBE2M expression in macrophages in liver and lung tissues postinfection was observed. To further clarify the role of UBE2M in macrophages, mice with macrophage-specific deletion of UBE2M (Lysm+Ube2mf/f) were constructed. Compared with control mice, these mice presented decreased levels of proinflammatory cytokines, such as IL-1β, IL-6, and TNF-α; reduced sepsis-induced organ damage; and improved survival. Notably, macrophage-specific deletion of UBE2M did not impair E. coli clearance. In vitro experiments also revealed that UBE2M-deficient macrophages produced fewer proinflammatory cytokines after E. coli infection without hindering E. coli clearance. RNA-sequencing analysis revealed that UBE2M deletion in macrophages after LPS stimulation notably suppressed transcriptional activation within the JAK-STAT and Toll-like receptor signaling pathways, which was further confirmed by gene set enrichment analysis. Additionally, Western blotting results confirmed that UBE2M deletion inhibited the activation of the NF-κB, ERK, and JAK-STAT signaling pathways. In conclusion, our findings indicate that specific deletion of UBE2M in macrophages protects against E. coli-induced sepsis by downregulating the excessive inflammatory response, potentially providing a novel strategy against sepsis by targeting UBE2M.

Neddylation of protein, a new strategy of protein post-translational modification for targeted treatment of central nervous system diseases

Neddylation, a type of protein post-translational modification that links the ubiquitin-like protein NEDD8 to substrate proteins, can be involved in various significant cellular processes and generate multiple biological effects. Currently, the best-characterized substrates of neddylation are the Cullin protein family, which is the core subunit of the Cullin-RING E3 ubiquitin ligase complex and controls many important biological processes by promoting ubiquitination and subsequent degradation of various key regulatory proteins. The normal or abnormal process of protein neddylation in the central nervous system can lead to a series of occurrences of normal functions and the development of diseases, providing an attractive, reasonable, and effective targeted therapeutic strategy. Therefore, this study reviews the phenomenon of neddylation in the central nervous system and summarizes the corresponding substrates. Finally, we provide a detailed description of neddylation involved in CNS diseases and treatment methods that may be used to regulate neddylation for the treatment of related diseases.

The blockade of neddylation alleviates ventilator-induced lung injury by reducing stretch-induced damage to pulmonary epithelial cells

Ventilator-induced lung injury is a serious complication in mechanically ventilated patients. Neddylation, the post-translational modification of neural precursor cell-expressed developmentally down-regulated 8 (NEDD8) conjugation, regulates numerous biological functions. However, its involvement and therapeutic significance in ventilator-induced lung injury remains unknown. Therefore, this study aimed to examine the kinetics and contribution of activated neddylation and the impact of neddylation inhibition in mice subjected to high tidal volume (HTV) ventilation in vivo and human pulmonary alveolar epithelial cells stimulated through cyclic stretching (CS) in vitro. The neddylation and expression of ubiquitin conjugating enzyme 3 (UBA3), a NEDD8-activating enzyme (NAE) catalytic subunit, were time-dependently upregulated in HTV-ventilated mice. Additionally, the NAE inhibitor MLN4924 considerably attenuated acute lung injury induced by HTV ventilation, manifesting as reduced inflammation and oxidative stress. Furthermore, MLN4924 effectively reduced the secretion of inflammatory cytokines from Ly6Chigh monocytes and neutrophils, subsequently decreasing endothelial permeability. Moreover, our study revealed an upregulation of the neddylation pathway, oxidative stress, and apoptosis during CS of alveolar epithelial cells. However, blockade of neddylation via MLN4924 or through UBA3 knockdown suppressed this upregulation. Overall, the inhibition of neddylation may alleviate HTV-induced acute lung injury by preventing CS-induced damage to alveolar epithelial cells. This indicates that the neddylation pathway plays a critical role in the progression of ventilator-induced lung injury. These findings may provide a new therapeutic target for treating ventilator-induced lung injury.

Neddylation signaling inactivation by tetracaine hydrochloride suppresses cell proliferation and alleviates vemurafenib-resistance of melanoma

Tetracaine, a local anesthetic, exhibits potent cytotoxic effects on multiple cancer; however, the precise underlying mechanisms of its anti-cancer activity remain uncertain. The anti-cancer activity of tetracaine was found to be the most effective among commonly used local anesthetics in this study. After tetracaine treatment, the differentially expressed genes in melanoma cells were identified by the RNAseq technique and enriched in the lysosome signaling pathway, cullin family protein binding, and proteasome signaling pathway through Kyoto Encyclopedia of Genes and Genomes. Additionally, the ubiquitin-like neddylation signaling pathway, which is hyperactivated in melanoma, could be abrogated due to decreased NAE2 expression after tetracaine treatment. The neddylation of the pro-oncogenic Survivin, which enhances its stability, was significantly reduced following treatment with tetracaine. The activation of neddylation signaling by NEDD8 overexpression could reduce the antitumor efficacy of tetracaine in vivo and in vitro. Furthermore, vemurafenib-resistant melanoma cells showed higher level of neddylation, and potential substrate proteins undergoing neddylation modification were identified through immunoprecipitation and mass spectrometry. The tetracaine treatment could reduce drug resistance via neddylation signaling pathway inactivation in melanoma cells. These findings demonstrate that tetracaine effectively inhibits cell proliferation and alleviates vemurafenib resistance in melanoma by suppressing the neddylation signaling pathway, providing a promising avenue for controlling cancer progression.

Targeting neddylation and sumoylation in chemoresistant triple negative breast cancer

Triple negative breast cancer (TNBC) accounts for 15-20% of breast cancer cases in the United States. Systemic neoadjuvant chemotherapy (NACT), with or without immunotherapy, is the current standard of care for patients with early-stage TNBC. However, up to 70% of TNBC patients have significant residual disease once NACT is completed, which is associated with a high risk of developing recurrence within two to three years of surgical resection. To identify targetable vulnerabilities in chemoresistant TNBC, we generated longitudinal patient-derived xenograft (PDX) models from TNBC tumors before and after patients received NACT. We then compiled transcriptomes and drug response profiles for all models. Transcriptomic analysis identified the enrichment of aberrant protein homeostasis pathways in models from post-NACT tumors relative to pre-NACT tumors. This observation correlated with increased sensitivity in vitro to inhibitors targeting the proteasome, heat shock proteins, and neddylation pathways. Pevonedistat, a drug annotated as a NEDD8-activating enzyme (NAE) inhibitor, was prioritized for validation in vivo and demonstrated efficacy as a single agent in multiple PDX models of TNBC. Pharmacotranscriptomic analysis identified a pathway-level correlation between pevonedistat activity and post-translational modification (PTM) machinery, particularly involving neddylation and sumoylation targets. Elevated levels of both NEDD8 and SUMO1 were observed in models exhibiting a favorable response to pevonedistat compared to those with a less favorable response in vivo. Moreover, a correlation emerged between the expression of neddylation-regulated pathways and tumor response to pevonedistat, indicating that targeting these PTM pathways may prove effective in combating chemoresistant TNBC.

Protein neddylation and its role in health and diseases

NEDD8 (Neural precursor cell expressed developmentally downregulated protein 8) is an ubiquitin-like protein that is covalently attached to a lysine residue of a protein substrate through a process known as neddylation, catalyzed by the enzyme cascade, namely NEDD8 activating enzyme (E1), NEDD8 conjugating enzyme (E2), and NEDD8 ligase (E3). The substrates of neddylation are categorized into cullins and non-cullin proteins. Neddylation of cullins activates CRLs (cullin RING ligases), the largest family of E3 ligases, whereas neddylation of non-cullin substrates alters their stability and activity, as well as subcellular localization. Significantly, the neddylation pathway and/or many neddylation substrates are abnormally activated or over-expressed in various human diseases, such as metabolic disorders, liver dysfunction, neurodegenerative disorders, and cancers, among others. Thus, targeting neddylation becomes an attractive strategy for the treatment of these diseases. In this review, we first provide a general introduction on the neddylation cascade, its biochemical process and regulation, and the crystal structures of neddylation enzymes in complex with cullin substrates; then discuss how neddylation governs various key biological processes via the modification of cullins and non-cullin substrates. We further review the literature data on dysregulated neddylation in several human diseases, particularly cancer, followed by an outline of current efforts in the discovery of small molecule inhibitors of neddylation as a promising therapeutic approach. Finally, few perspectives were proposed for extensive future investigations.

Advancements in colorectal cancer research: Unveiling the cellular and molecular mechanisms of neddylation (Review)

Neddylation, akin to ubiquitination, represents a post‑translational modification of proteins wherein neural precursor cell‑expressed developmentally downregulated protein 8 (NEDD8) is modified on the substrate protein through a series of reactions. Neddylation plays a pivotal role in the growth and proliferation of animal cells. In colorectal cancer (CRC), it predominantly contributes to the proliferation, metastasis and survival of tumor cells, decreasing overall patient survival. The strategic manipulation of the NEDD8‑mediated neddylation pathway holds immense therapeutic promise in terms of the potential to modulate the growth of tumors by regulating diverse biological responses within cancer cells, such as DNA damage response and apoptosis, among others. MLN4924 is an inhibitor of NEDD8, and its combined use with platinum drugs and irinotecan, as well as cycle inhibitors and NEDD activating enzyme inhibitors screened by drug repurposing, has been found to exert promising antitumor effects. The present review summarizes the recent progress made in the understanding of the role of NEDD8 in the advancement of CRC, suggesting that NEDD8 is a promising anti‑CRC target.

Neddylation suppression by a macrophage membrane-coated nanoparticle promotes dual immunomodulatory repair of diabetic wounds

Oxidative stress, infection, and vasculopathy caused by hyperglycemia are the main barriers for the rapid repair of foot ulcers in patients with diabetes mellitus (DM). In recent times, the discovery of neddylation, a new type of post-translational modification, has been found to regulate various crucial biological processes including cell metabolism and the cell cycle. Nevertheless, its capacity to control the healing of wounds in diabetic patients remains unknown. This study shows that MLN49224, a compound that inhibits neddylation at low concentrations, enhances the healing of diabetic wounds by inhibiting the polarization of M1 macrophages and reducing the secretion of inflammatory factors. Moreover, it concurrently stimulates the growth, movement, and formation of blood vessel endothelial cells, leading to expedited healing of wounds in individuals with diabetes. The drug is loaded into biomimetic macrophage-membrane-coated PLGA nanoparticles (M-NPs/MLN4924). The membrane of macrophages shields nanoparticles from being eliminated in the reticuloendothelial system and counteracts the proinflammatory cytokines to alleviate inflammation in the surrounding area. The extended discharge of MLN4924 from M-NPs/MLN4924 stimulates the growth of endothelial cells and the formation of tubes, along with the polarization of macrophages towards the anti-inflammatory M2 phenotype. By loading M-NPs/MLN4924 into a hydrogel, the final formulation is able to meaningfully repair a diabetic wound, suggesting that M-NPs/MLN4924 is a promising engineered nanoplatform for tissue engineering.

Emerging role of NEDD8-mediated neddylation in age-related metabolic diseases

Aging in humans is associated with abdominal distribution and remodeling of body fat and a parallel gradual increase in the prevalence of metabolic diseases such as obesity, type 2 diabetes mellitus and fatty liver disease, as well as the risk of developing metabolic complications. Current treatments might be improved by understanding the detailed mechanisms underlying the onset of age-related metabolic disorders. Neddylation, a post-translational modification that adds the ubiquitin-like protein NEDD8 to substrate proteins, has recently been linked to age-related metabolic diseases, opening new avenues of investigation and raising a potential target for treatment of these diseases. In this review, we will focus on the potential role of NEDD8-mediated neddylation in age-related metabolic dysregulation, insulin resistance, obesity, type 2 diabetes mellitus and fatty liver. We propose that alterations in NEDD8-mediated neddylation contribute to triggering insulin resistance and the development of age-related metabolic dysregulation, thus highlighting NEDD8 as a promising therapeutic target for preventing age-related metabolic diseases.

Role of the ubiquitin-proteasome system on macrophages in the tumor microenvironment

Tumor-associated macrophages (TAMs) are key components of the tumor microenvironment, and their different polarization states play multiple roles in tumors by secreting cytokines, chemokines, and so on, which are closely related to tumor development. In addition, the enrichment of TAMs is often associated with poor prognosis of tumors. Thus, targeting TAMs is a potential tumor treatment strategy, in which therapeutic approaches such as reducing TAMs numbers, remodeling TAMs phenotypes, and altering their functions are being extensively investigated. Meanwhile, the ubiquitin-proteasome system (UPS), an important mechanism of protein hydrolysis in eukaryotic cells, participates in cellular processes by regulating the activity and stability of key proteins. Interestingly, UPS plays a dual role in the process of tumor development, and its role in TAMs deserve to be investigated in depth. This review builds on this foundation to further explore the multiple roles of UPS on TAMs and identifies a promising approach to treat tumors by targeting TAMs with UPS.

Advancements and perspectives of RBX2 as a molecular hallmark in cancer

Cancer is a challenging issue for human health. One of the key methods to address this issue is by comprehending the molecular causes of tumors and creating medications that target those causes. RBX2 (RING box protein 2), also known as ROC2 (Regulator of Cullins 2), RNF7 (RING Finger Protein 7), or SAG (Sensitive to Apoptosis Gene) is a key component of the Cullin-RING-type E3 ubiquitin ligases (CRLs) and overexpressed in various human cancers. RBX2 is a potential drug target, the expression of which correlates with tumor staging, grading, and prognosis analysis. Through a synergistically biological interaction with Kras mutation in preclinical models, RBX2 accelerated the progression of skin cancer, pancreatic cancer, and lung cancer. In accordance, the aberrant expression of RBX2 will lead to dysregulation of many signaling pathways, which is crucial for tumor initiation and growth. However, the impact of RBX2 on tumors also intriguingly demonstrates a spatial reliance manner. In this review, we summarized the current understanding of RBX2 in multiple cancer types and suggested a significant potential of RBX2 as a therapeutic target.

Deciphering the role of neddylation in tumor microenvironment modulation: common outcome of multiple signaling pathways

Neddylation is a post-translational modification process, similar to ubiquitination, that controls several biological processes. Notably, it is often aberrantly activated in neoplasms and plays a critical role in the intricate dynamics of the tumor microenvironment (TME). This regulatory influence of neddylation permeates extensively and profoundly within the TME, affecting the behavior of tumor cells, immune cells, angiogenesis, and the extracellular matrix. Usually, neddylation promotes tumor progression towards increased malignancy. In this review, we highlight the latest understanding of the intricate molecular mechanisms that target neddylation to modulate the TME by affecting various signaling pathways. There is emerging evidence that the targeted disruption of the neddylation modification process, specifically the inhibition of cullin-RING ligases (CRLs) functionality, presents a promising avenue for targeted therapy. MLN4924, a small-molecule inhibitor of the neddylation pathway, precisely targets the neural precursor cell-expressed developmentally downregulated protein 8 activating enzyme (NAE). In recent years, significant advancements have been made in the field of neddylation modification therapy, particularly the integration of MLN4924 with chemotherapy or targeted therapy. This combined approach has demonstrated notable success in the treatment of a variety of hematological and solid tumors. Here, we investigated the inhibitory effects of MLN4924 on neddylation and summarized the current therapeutic outcomes of MLN4924 against various tumors. In conclusion, this review provides a comprehensive, up-to-date, and thorough overview of neddylation modifications, and offers insight into the critical importance of this cellular process in tumorigenesis.

Neddylation Regulation of Immune Responses

Neddylation plays a vital role in post-translational modification, intricately shaping the regulation of diverse biological processes, including those related to cellular immune responses. In fact, neddylation exerts control over both innate and adaptive immune systems via various mechanisms. Specifically, neddylation influences the function and survival of innate immune cells, activation of pattern recognition receptors and GMP-AMP synthase-stimulator of interferon genes pathways, as well as the release of various cytokines in innate immune reactions. Moreover, neddylation also governs the function and survival of antigen-presenting cells, which are crucial for initiating adaptive immune reactions. In addition, neddylation regulates T cell activation, proliferation, differentiation, survival, and their effector functions, thereby ensuring an appropriate adaptive immune response. In this review, we summarize the most recent findings in these aspects and delve into the connection between dysregulated neddylation events and immunological disorders, especially inflammatory diseases. Lastly, we propose future directions and potential treatments for these diseases by targeting neddylation.

Pevonedistat, a first-in-class NEDD8-activating enzyme inhibitor, sensitizes cancer cells to VSVΔ51 oncolytic virotherapy

The clinical efficacy of VSVΔ51 oncolytic virotherapy has been limited by tumor resistance to viral infection, so strategies to transiently repress antiviral defenses are warranted. Pevonedistat is a first-in-class NEDD8-activating enzyme (NAE) inhibitor currently being tested in clinical trials for its antitumor potential. In this study, we demonstrate that pevonedistat sensitizes human and murine cancer cells to increase oncolytic VSVΔ51 infection, increase tumor cell death, and improve therapeutic outcomes in resistant syngeneic murine cancer models. Increased VSVΔ51 infectivity was also observed in clinical human tumor samples. We further identify the mechanism of this effect to operate via blockade of the type 1 interferon (IFN-1) response through neddylation-dependent interferon-stimulated growth factor 3 (ISGF3) repression and neddylation-independent inhibition of NF-κB nuclear translocation. Together, our results identify a role for neddylation in regulating the innate immune response and demonstrate that pevonedistat can improve the therapeutic outcomes of strategies using oncolytic virotherapy.

[Differential expression of NEDD8 in different pathological types of chronic rhinosinusitis with nasal polyps]

Objective:To analyze the differential expression of neural precursor cell-expressed developmentally downregulated 8（NEDD8） protein in nasal polyp tissues of patients with different pathological types of chronic rhinorhinosinusitis with nasal polyps（CRSwNP）. Methods:All specimens were obtained from the specimen library of Beijing Tongren Hospital, and were all patients who underwent nasal endoscopic surgery for chronic rhinosinusitis in Beijing Tongren Hospital. Hematoxylin-eosin staining（HE） was used to detect the number of eosinophils in nasal polyps, and CRSwNP patients were grouped according to the number of eosinophils in nasal polyps, immunohistochemistry was used to detect and analyze the expression level of NEDD8 protein in nasal polyps. Results:The expression level of NEDD8 protein in nasal polyps of patients with eosinophilic chronic rhinorhinosinusitis with nasal polyps was significantly higher than that of patients with non-eosinophilic chronic rhinosinusitis and nasal polyps（P<0.05）. In addition, there was a significant positive correlation between the expression level of NEDD8 protein and the number of eosinophils in nasal polyp tissue（r=0.79, P=0.02）. Conclusion:There are differences in the expression of NEDD8 protein in patients with chronic rhinosinusitis and nasal polyps of different pathological types.

Targeting NEDD8-activating enzyme for cancer therapy: developments, clinical trials, challenges and future research directions

NEDDylation, a post-translational modification through three-step enzymatic cascades, plays crucial roles in the regulation of diverse biological processes. NEDD8-activating enzyme (NAE) as the only activation enzyme in the NEDDylation modification has become an attractive target to develop anticancer drugs. To date, numerous inhibitors or agonists targeting NAE have been developed. Among them, covalent NAE inhibitors such as MLN4924 and TAS4464 currently entered into clinical trials for cancer therapy, particularly for hematological tumors. This review explains the relationships between NEDDylation and cancers, structural characteristics of NAE and multistep mechanisms of NEDD8 activation by NAE. In addition, the potential approaches to discover NAE inhibitors and detailed pharmacological mechanisms of NAE inhibitors in the clinical stage are explored in depth. Importantly, we reasonably investigate the challenges of NAE inhibitors for cancer therapy and possible development directions of NAE-targeting drugs in the future.

NEDD8-conjugating enzyme E2s: critical targets for cancer therapy

NEDD8-conjugating enzymes, E2s, include the well-studied ubiquitin-conjugating enzyme E2 M (UBE2M) and the poorly characterized ubiquitin-conjugating enzyme E2 F (UBE2F). UBE2M and UBE2F have distinct and prominent roles in catalyzing the neddylation of Cullin or non-Cullin substrates. These enzymes are overexpressed in various malignancies, conferring a worse overall survival. Targeting UBE2M to influence tumor growth by either modulating several biological responses of tumor cells (such as DNA-damage response, apoptosis, or senescence) or regulating the anti-tumor immunity holds strong therapeutic potential. Multiple inhibitors that target the interaction between UBE2M and defective cullin neddylation protein 1 (DCN1), a co-E3 for neddylation, exhibit promising anti-tumor effects. By contrast, the potential benefits of targeting UBE2F are still to be explored. It is currently reported to inhibit apoptosis and then induce cell growth; hence, targeting UBE2F serves as an effective chemo-/radiosensitizing strategy by triggering apoptosis. This review highlights the most recent advances in the roles of UBE2M and UBE2F in tumor progression, indicating these E2s as two promising anti-tumor targets.

Triterpenoid CDDO-EA inhibits lipopolysaccharide-induced inflammatory responses in skeletal muscle cells through suppression of NF-κB

Chronic inflammation is a major contributor to the development of obesity-induced insulin resistance, which then can lead to the development of type 2 diabetes (T2D). Skeletal muscle plays a pivotal role in insulin-stimulated whole-body glucose disposal. Therefore, dysregulation of glucose metabolism by inflammation in skeletal muscle can adversely affect skeletal muscle insulin sensitivity and contribute to the pathogenesis of T2D. The mechanism underlying insulin resistance is not well known; however, macrophages are important initiators in the development of the chronic inflammatory state leading to insulin resistance. Skeletal muscle consists of resident macrophages which can be activated by lipopolysaccharide (LPS). These activated macrophages affect myocytes via a paracrine action of pro-inflammatory mediators resulting in secretion of myokines that contribute to inflammation and ultimately skeletal muscle insulin resistance. Therefore, knowing that synthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acids (CDDOs) can attenuate macrophage pro-inflammatory responses in chronic disorders, such as cancer and obesity, and that macrophage pro-inflammatory responses can modulate skeletal muscle inflammation, we first examined whether CDDO-ethyl amide (CDDO-EA) inhibited chemokine and cytokine production in macrophages since this had not been reported for CDDO-EA. CDDO-EA blocked LPS-induced tumor necrosis factor-alpha (TNF-α), monocyte chemotactic protein-1 (MCP-1), interleukine-1beta (IL-1β), and interleukine-6 (IL-6) production in RAW 264.7 mouse and THP-1 human macrophages. Although many studies show that CDDOs have anti-inflammatory properties in several tissues and cells, little is known about the anti-inflammatory effects of CDDOs on skeletal muscle. We hypothesized that CDDO-EA protects skeletal muscle from LPS-induced inflammation by blocking nuclear factor kappa B (NF-κB) signaling. Our studies demonstrate that CDDO-EA prevented LPS-induced TNF-α and MCP-1 gene expression by inhibiting the NF-κB signaling pathway in L6-GLUT4myc rat myotubes. Our findings suggest that CDDO-EA suppresses LPS-induced inflammation in macrophages and myocytes and that CDDO-EA is a promising compound as a therapeutic agent for protecting skeletal muscle from inflammation.

Inhibition of Neddylation Suppresses Osteoclast Differentiation and Function In Vitro and Alleviates Osteoporosis In Vivo

Neddylation, or the covalent addition of NEDD8 to specific lysine residue of proteins, is a reversible posttranslational modification, which regulates numerous biological functions; however, its involvement and therapeutic significance in osteoporosis remains unknown. Our results revealed that during the soluble receptor activator of nuclear factor-κB ligand (sRANKL)-stimulated osteoclast differentiation, the neddylation and expression of UBA3, the NEDD8-activating enzyme (NAE) catalytic subunit, were dose- and time-dependently upregulated in RAW 264.7 macrophages. UBA3 knockdown for diminishing NAE activity or administering low doses of the NAE inhibitor MLN4924 significantly suppressed sRANKL-stimulated osteoclast differentiation and bone-resorbing activity in the macrophages by inhibiting sRANKL-stimulated neddylation and tumor necrosis factor receptor-associated factor 6 (TRAF6)-activated transforming growth factor-β-activated kinase 1 (TAK1) downstream signaling for diminishing nuclear factor-activated T cells c1 (NFATc1) expression. sRANKL enhanced the interaction of TRAF6 with the neddylated proteins and the polyubiquitination of TRAF6's lysine 63, which activated TAK1 downstream signaling; however, this process was inhibited by MLN4924. MLN4924 significantly reduced osteoporosis in an ovariectomy- and sRANKL-induced osteoporosis mouse model in vivo. Our novel finding was that NAE-mediated neddylation participates in RANKL-activated TRAF6-TAK1-NFATc1 signaling during osteoclast differentiation and osteoporosis, suggesting that neddylation may be a new target for treating osteoporosis.

Neddylation pattern indicates tumor microenvironment characterization and predicts prognosis in lung adenocarcinoma

Background: Lung adenocarcinoma (LUAD) is the most common type of lung cancer with a complex tumor microenvironment. Neddylation, as a type of post-translational modification, plays a vital role in the development of LUAD. To date, no study has explored the potential of neddylation-associated genes for LUAD classification, prognosis prediction, and treatment response evaluation.

Methods: Seventy-six neddylation-associated prognostic genes were identified by Univariate Cox analysis. Patients with LUAD were classified into two patterns based on unsupervised consensus clustering analysis. In addition, a 10-gene prognostic signature was constructed using LASSO-Cox and a multivariate stepwise regression approach.

Results: Substantial differences were observed between the two patterns of LUAD in terms of prognosis. Compared with neddylation cluster2, neddylation cluster1 exhibited low levels of immune infiltration that promote tumor progression. Additionally, the neddylation-related risk score correlated with clinical parameters and it can be a good predictor of patient outcomes, gene mutation levels, and chemotherapeutic responses.

Conclusion: Neddylation patterns can distinguish tumor microenvironment and prognosis in patients with LUAD. Prognostic signatures based on neddylation-associated genes can predict patient outcomes and guide personalized treatment.

Association Between Neddylation and Immune Response

Neddylation is a ubiquitin-like post-translational protein modification. It occurs via the activation of the neural precursor cell expressed, developmentally downregulated protein 8 (NEDD8) by three enzymes: activating enzyme, conjugating enzyme, and ligase. NEDD8 was first isolated from the mouse brain in 1992 and was initially considered important for the development and differentiation of the central nervous system. Previously, the downregulation of neddylation was associated with some human diseases, such as neurodegenerative disorders and cancers. In recent years, neddylation has also been proven to be pivotal in various processes of the human immune system, including the regulation of inflammation, bacterial infection, viral infection, and T cell function. Additionally, NEDD8 was found to act on proteins that can affect viral transcription, leading to impaired infectivity. Here, we focused on the influence of neddylation on the innate and adaptive immune responses.

A Multitarget Therapeutic Peptide Derived From Cytokine Receptors Based on in Silico Analysis Alleviates Cytokine-Stimulated Inflammation

Septicemia is a severe inflammatory response caused by the invasion of foreign pathogens. Severe sepsis-induced shock and multiple organ failure are the two main causes of patient death. The overexpression of many proinflammatory cytokines, such as TNF-α, IL-1β, and IL-6, is closely related to severe sepsis. Although the treatment of sepsis has been subject to many major breakthroughs of late, the treatment of patients with septic shock is still accompanied by a high mortality rate. In our previous research, we used computer simulations to design the multifunctional peptide KCF18 that can bind to TNF-α, IL-1β, and IL-6 based on the binding regions of receptors and proinflammatory cytokines. In this study, proinflammatory cytokines were used to stimulate human monocytes to trigger an inflammatory response, and the anti-inflammatory ability of the multifunctional KCF18 peptide was further investigated. Cell experiments demonstrated that KCF18 significantly reduced the binding of proinflammatory cytokines to their cognate receptors and inhibited the mRNA and protein expressions of TNF-α, IL-1β, and IL-6. It could also reduce the expression of reactive oxygen species induced by cytokines in human monocytes. KCF18 could effectively decrease the p65 nucleus translocation induced by cytokines, and a mice endotoxemia experiment demonstrated that KCF18 could reduce the expression of IL-6 and the increase of white blood cells in the blood stimulated by lipopolysaccharides. According to our study of tissue sections, KCF18 alleviated liver inflammation. By reducing the release of cytokines in plasma and directly affecting vascular cells, KCF18 is believed to significantly reduce the risk of vascular inflammation.

The NEDD8-activating enzyme inhibitor MLN4924 reduces ischemic brain injury in mice

Ischemic stroke is a leading cause of death and disability with limited therapies. Neuronal precursor cell-expressed developmentally downregulated protein 8 (NEDD8) is a ubiquitin-like protein that is involved in protein neddylation. The first-in-class anticancer agent called MLN4924 plays a crucial role in suppressing tumorigenesis and attenuating inflammatory responses due to specifically inhibiting NEDD8-activating enzyme. Here, we investigated the potential protective role of MLN4924 after experimental stroke. We showed that the neddylation pathway is overactivated in the brain following cerebral ischemia. Inhibition of neddylation by MLN4924 protects the brain against ischemic injury by attenuating neutrophil extravasation and maintaining blood–brain barrier integrity. Our findings provide insights into the promising treatment with neddylation inhibition for ischemic brain injury.

Blood–brain barrier (BBB) breakdown and inflammation occurring at the BBB have a key, mainly a deleterious role in the pathophysiology of ischemic stroke. Neddylation is a ubiquitylation-like pathway that is critical in various cellular functions by conjugating neuronal precursor cell-expressed developmentally down-regulated protein 8 (NEDD8) to target proteins. However, the roles of neddylation pathway in ischemic stroke remain elusive. Here, we report that NEDD8 conjugation increased during acute phase after ischemic stroke and was present in intravascular and intraparenchymal neutrophils. Inhibition of neddylation by MLN4924, also known as pevonedistat, inactivated cullin-RING E3 ligase (CRL), and reduced brain infarction and improved functional outcomes. MLN4924 treatment induced the accumulation of the CRL substrate neurofibromatosis 1 (NF1). By using virus-mediated NF1 silencing, we show that NF1 knockdown abolished MLN4924-dependent inhibition of neutrophil trafficking. These effects were mediated through activation of endothelial P-selectin and intercellular adhesion molecule-1 (ICAM-1), and blocking antibodies against P-selectin or anti–ICAM-1 antibodies reversed NF1 silencing-induced increase in neutrophil infiltration in MLN4924-treated mice. Furthermore, we found that NF1 silencing blocked MLN4924-afforded BBB protection and neuroprotection through activation of protein kinase C δ (PKCδ), myristoylated alanine-rich C-kinase substrate (MARCKS), and myosin light chain (MLC) in cerebral microvessels after ischemic stroke, and treatment of mice with the PKCδ inhibitor rottlerin reduced this increased BBB permeability. Our study demonstrated that increased neddylation promoted neutrophil trafficking and thus exacerbated injury of the BBB and stroke outcomes. We suggest that the neddylation inhibition may be beneficial in ischemic stroke.

Discovery of Potent and Selective 2-(Benzylthio)pyrimidine-based DCN1-UBC12 Inhibitors for Anticardiac Fibrotic Effects

DCN1, a co-E3 ligase, interacts with UBC12 and activates cullin-RING ligases (CRLs) by catalyzing cullin neddylation. Although DCN1 has been recognized as an important therapeutic target for human diseases, its role in the cardiovascular area remains unknown. Here, we first found that DCN1 was upregulated in isolated cardiac fibroblasts (CFs) treated by angiotensin (Ang) II and in mouse hearts after pressure overload. Then, structure-based optimizations for DCN1-UBC12 inhibitors were performed based on our previous work, yielding compound DN-2. DN-2 specifically targeted DCN1 at molecular and cellular levels as shown by molecular modeling studies, HTRF, cellular thermal shift and co-immunoprecipitation assays. Importantly, DN-2 effectively reversed Ang II-induced cardiac fibroblast activation, which was associated with the inhibition of cullin 3 neddylation. Our findings indicate a potentially unrecognized role of DCN1 inhibition for anticardiac fibrotic effects. DN-2 may be used as a lead compound for further development.

Dietary plant pigment on blood-digestive physiology, antioxidant-immune response, and inflammatory gene transcriptional regulation in spotted snakehead (Channa punctata) infected with Pseudomonas aeruginosa

The current study addressed to investigate the effect of lycopene (LYC) on blood physiology, digestive-antioxidant enzyme activity, specific-nonspecific immune response, and inflammatory gene transcriptional regulation (cytokines, heat shock proteins, vitellogenins) in spotted snakehead (Channa punctata) against Pseudomonas aeruginosa. In unchallenged and challenged fish treated with 200 mg LYC enriched diet the growth performance and digestive-antioxidant enzymes increased after 30 days, whereas with inclusion of 100 or 400 mg LYC in the diets, the increase manifested on or after 45 days. No mortality in fish treated with any LYC diet against P. aeruginosa was revealed. In the unchallenged and challenged fish the phagocytic (PC) activity in head kidney (HK) and spleen were significantly enhanced when fed the control diet or other LYC diets, whereas the respiratory burst (RB) activity and nitric oxide (NO) production significantly increased when fed the 200 mg diet for 45 and 60 days. Similarly, the lysozyme (Lyz) activity in the HK and spleen, and total Ig content in serum were significantly higher in both groups fed the 200 mg LYC diet for 15, 45, and 60 days. Heat shock protein (Hsp 70) was significantly improved in the uninfected group fed the 200 mg LYC diet for 45 and 60 days, but Hsp27 did not significantly change among the experimental groups at any time points. TNF-α and IL-6 mRNA pro-inflammatory cytokine expression significantly increased in both groups fed the 200 mg LYC diet after 45 and 60 days, while the IL-12 mRNA expression was moderate in both groups fed the same diet for 60 days. The IL-10 did not significant mRNA expression between groups at any sampling. The iNOS and NF-κB mRNA expression was pointedly high in both groups fed the 200 mg LYC diet on day 45 and 60. Vitellogenin A (VgA) mRNA was significantly higher in the uninfected fish fed the 100 and 200 mg LYC diets for 45 and 60 days, but VgB did not reveal significant difference between the treatment groups at any time points. The present results suggest that supplementation of LYC at 200 mg significantly modulate the blood physiology, digestive-antioxidant enzymes, specific-nonspecific immune parameters, and cytokines, Hsp, and vitellogenins in spotted snakehead against P. aeruginosa.

Insights into the post-translational modification and its emerging role in shaping the tumor microenvironment

More and more in-depth studies have revealed that the occurrence and development of tumors depend on gene mutation and tumor heterogeneity. The most important manifestation of tumor heterogeneity is the dynamic change of tumor microenvironment (TME) heterogeneity. This depends not only on the tumor cells themselves in the microenvironment where the infiltrating immune cells and matrix together forming an antitumor and/or pro-tumor network. TME has resulted in novel therapeutic interventions as a place beyond tumor beds. The malignant cancer cells, tumor infiltrate immune cells, angiogenic vascular cells, lymphatic endothelial cells, cancer-associated fibroblastic cells, and the released factors including intracellular metabolites, hormonal signals and inflammatory mediators all contribute actively to cancer progression. Protein post-translational modification (PTM) is often regarded as a degradative mechanism in protein destruction or turnover to maintain physiological homeostasis. Advances in quantitative transcriptomics, proteomics, and nuclease-based gene editing are now paving the global ways for exploring PTMs. In this review, we focus on recent developments in the PTM area and speculate on their importance as a critical functional readout for the regulation of TME. A wealth of information has been emerging to prove useful in the search for conventional therapies and the development of global therapeutic strategies.

Ubiquitin pathways regulate the pathogenesis of chronic liver disease

Chronic liver disease (CLD) is considered the leading cause of global mortality. In westernized countries, increased consumption of alcohol and overeating foods with high fat/ high glucose promote progression of CLD such as alcoholic liver disease (ALD) and non-alcoholic liver disease (NAFLD). Accumulating evidence and research suggest that ubiquitin, a 75 amino acid protein, plays crucial role in the pathogenesis of CLD through dynamic post-translational modifications (PTMs) exerting diverse cellular outcomes such as protein degradation through ubiquitin-proteasome system (UPS) and autophagy, and regulation of signal transduction. In this review, we present the function of ubiquitination and latest findings on diverse mechanism of PTMs, UPS and autophagy which significantly contribute to the pathogenesis of alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), cirrhosis, and HCC. Despite its high prevalence, morbidity, and mortality, there are only few FDA approved drugs that could be administered to CLD patients. The goal of this review is to present a variety of pathways and therapeutic targets involving ubiquitination in the pathogenesis of CLD. Further, this review summarizes collective views of pharmaceutical inhibition or activation of recent drugs targeting UPS and autophagy system to highlight potential targets and new approaches to treat CLD.

Neddylation Alleviates Methicillin-Resistant Staphylococcus aureus Infection by Inducing Macrophage Reactive Oxygen Species Production

Neddylation, a posttranslational modification in which NEDD8 is covalently attached to target proteins, has emerged as an endogenous regulator of innate immunity. However, the role of neddylation in methicillin-resistant Staphylococcus aureus (MRSA) infection remains unknown. In this study, we found that neddylation was activated after MRSA infection in vivo and in vitro. Inhibition of neddylation with MLN4924 promoted injury of liver and kidneys in C57BL/6 mice with MRSA bloodstream infection and increased mortality. Blockade of neddylation, either pharmacologically (MLN4924, DI591) or through the use of Uba3 small interfering RNA, inhibited Cullin3 neddylation and promoted Nrf2 accumulation, thus reducing reactive oxygen species (ROS) induction and bacterial killing ability in mouse peritoneal macrophages. In summary, our findings suggest that activation of neddylation in macrophages plays a critical protective role against MRSA infection by increasing ROS production, partially by signaling through the NEDD8-Cullin3-Nrf2-ROS axis. Furthermore, our results may provide a new non-antibiotic treatment strategy for MRSA infection through targeting of neddylation.

Neddylation inhibition ameliorates steatosis in NAFLD by boosting hepatic fatty acid oxidation via the DEPTOR-mTOR axis

OBJECTIVE

Neddylation is a druggable and reversible ubiquitin-like post-translational modification upregulated in many diseases, including liver fibrosis, hepatocellular carcinoma, and more recently, non-alcoholic fatty liver disease (NAFLD). Herein, we propose to address the effects of neddylation inhibition and the underlying mechanisms in pre-clinical models of NAFLD.

METHODS

Hepatic neddylation measured by immunohistochemical analysis and NEDD8 serum levels measured by ELISA assay were evaluated in NAFLD clinical and pre-clinical samples. The effects of neddylation inhibition by using a pharmacological small inhibitor, MLN4924, or molecular approaches were assessed in isolated mouse hepatocytes and pre-clinical mouse models of diet-induced NAFLD, male adult C57BL/6 mice, and the AlfpCre transgenic mice infected with AAV-DIO-shNedd8.

RESULTS

Neddylation inhibition reduced lipid accumulation in oleic acid-stimulated mouse primary hepatocytes and ameliorated liver steatosis, preventing lipid peroxidation and inflammation in the mouse models of diet-induced NAFLD. Under these conditions, increased Deptor levels and the concomitant repression of mTOR signaling were associated with augmented fatty acid oxidation and reduced lipid content. Moreover, Deptor silencing in isolated mouse hepatocytes abolished the anti-steatotic effects mediated by neddylation inhibition. Finally, serum NEDD8 levels correlated with hepatic neddylation during the disease progression in the clinical and pre-clinical models CONCLUSIONS: Overall, the upregulation of Deptor, driven by neddylation inhibition, is proposed as a novel effective target and therapeutic approach to tackle NAFLD.

Inhibition of HDAC6 Activity Protects Against Endothelial Dysfunction and Atherogenesis in vivo: A Role for HDAC6 Neddylation

We previously reported that histone deacetylase 6 (HDAC6) has an important role in endothelial cell (EC) function in vitro. However, whether HDAC6 plays a role in atherogenesis in vivo and the mechanism(s) that control HDAC6 activity/expression in response to atherogenic stimuli are unclear. The goals of this study were to determine whether HDAC6 inhibitor tubacin attenuates atherogenesis and to elucidate specific molecular mechanism(s) that regulate endothelial HDAC6 expression/activity. We evaluated whether administration of tubacin attenuated or reversed the endothelial dysfunction and atherosclerosis induced in mice by a single intraperitoneal injection of adeno-associated viruses encoding liver-target PCSK9 gain-of-function mutant followed by a high fat diet (HFD) for 18 weeks. Tubacin significantly blunted PCSK9-induced increases in pulse wave velocity (index of vascular stiffness and overall vascular health) that are also seen in atherogenic mice. Furthermore, tubacin protected vessels from defective vasorelaxation, as evaluated by acetylcholine-mediated relaxation using wire myograph. Plaque burden defined by Oil Red O staining was also found to be significantly less in mice that received tubacin than in those that received PCSK9 alone. Inhibition of the NEDDylation pathway with MLN4924, an inhibitor of NEDD8-activating enzyme 1 (NAE1), significantly increased HDAC6 activity in HAECs. Interestingly, HDAC6 expression remained unchanged. Further, HAECs exposed to the atherogenic stimulus oxidized low-density lipoprotein (OxLDL) exhibited enhanced HDAC6 activity, which was attenuated by pretreatment with MLN4924. The HDAC6 NEDDylation molecular pathway might regulate genes related to endothelial control of vasomotor tone, reactivity, and atherosclerosis. Tubacin may represent a novel pharmacologic intervention for atherogenesis and other vasculopathies.

Neddylation Regulates Macrophages and Implications for Cancer Therapy

Tumor-associated macrophages (TAMs) promote cancer progression via stimulating angiogenesis, invasion/metastasis, and suppressing anti-cancer immunity. Targeting TAMs is a potential promising cancer therapeutic strategy. Neddylation adds the ubiquitin-like protein NEDD8 to substrates, and thereby regulates diverse biological processes in multiple cell types, including macrophages. By controlling cellular responses, the neddylation pathway regulates the function, migration, survival, and polarization of macrophages. In the present review we summarized how the neddylation pathway modulates Macrophages and its implications for cancer therapy.

Cell type-specific transcriptomics identifies neddylation as a novel therapeutic target in multiple sclerosis

Multiple sclerosis is an autoimmune disease of the CNS in which both genetic and environmental factors are involved. Genome-wide association studies revealed more than 200 risk loci, most of which harbour genes primarily expressed in immune cells. However, whether genetic differences are translated into cell-specific gene expression profiles and to what extent these are altered in patients with multiple sclerosis are still open questions in the field. To assess cell type-specific gene expression in a large cohort of patients with multiple sclerosis, we sequenced the whole transcriptome of fluorescence-activated cell sorted T cells (CD4+ and CD8+) and CD14+ monocytes from treatment-naive patients with multiple sclerosis (n = 106) and healthy subjects (n = 22). We identified 479 differentially expressed genes in CD4+ T cells, 435 in monocytes, and 54 in CD8+ T cells. Importantly, in CD4+ T cells, we discovered upregulated transcripts from the NAE1 gene, a critical subunit of the NEDD8 activating enzyme, which activates the neddylation pathway, a post-translational modification analogous to ubiquitination. Finally, we demonstrated that inhibition of NEDD8 activating enzyme using the specific inhibitor pevonedistat (MLN4924) significantly ameliorated disease severity in murine experimental autoimmune encephalomyelitis. Our findings provide novel insights into multiple sclerosis-associated gene regulation unravelling neddylation as a crucial pathway in multiple sclerosis pathogenesis with implications for the development of tailored disease-modifying agents.

Neddylation pathway alleviates chronic pancreatitis by reducing HIF1α-CCL5-dependent macrophage infiltration

Chronic pancreatitis (CP) is characterized by a wide range of irreversible fibro-inflammatory diseases with largely ambiguous pathogenesis. Although neddylation pathway has been implicated in regulating immune responses, whether the dysregulation of neddylation is involved in the progression of CP and how neddylation regulates the inflammatory microenvironment of CP have not yet been reported. Here, we demonstrate that global inactivation of neddylation pathway by MLN4924 significantly exacerbates chronic pancreatitis. The increased M2 macrophage infiltration, mediated by the upregulated chemokine (C-C motif) ligand 5 (CCL5), is responsible for the enhanced pancreatitis-promoting activity of MLN4924. Both CCL5 blockade and macrophage depletion contribute to alleviating pancreatic fibrosis and inflammation in MLN4924-treated CP mice. Mechanistic investigation identifies that inactivation of Cullin-RING ligases (CRLs) stabilizes cellular levels of hypoxia-inducible factor 1α (HIF-1α), which increases CCL5 expression by promoting CCL5 transactivation. Clinically, UBE2M expression remarkably decreases in human CP tissues compared with normal specimens and the levels of CCL5 and M2 marker CD163 are negatively correlated with UBE2M intensity, suggesting that neddylation is involved in the pathogenesis of pancreatitis. Hence, our studies reveal a neddylation-associated immunopathogenesis of chronic pancreatitis and provide new ideas for the disease treatment.

A first-in-human, phase 1 study of the NEDD8 activating enzyme E1 inhibitor TAS4464 in patients with advanced solid tumors

Background This open-label, phase 1 study investigated TAS4464, a potent NEDD8-activating enzyme inhibitor, in patients with advanced/metastatic solid tumors (JapicCTI-173,488; registered 13/01/2017). The primary objective was dose-limiting toxicities (DLTs). Maximum-tolerated dose (MTD) was investigated using an accelerated titration design. Methods The starting 10-mg/m² dose was followed by an initial accelerated stage (weekly dosing; n = 11). Based on liver function test (LFT) results, a 14-day, 20-mg/m² dose lead-in period was implemented (weekly dosing with lead-in; n = 6). Results Abnormal LFT changes and gastrointestinal effects were the most common treatment-related adverse events (AEs). DLTs with 56-mg/m² weekly dosing occurred in 1/5 patients; five patients had grade ≥ 2 abnormal LFT changes at 40- and 56-mg/m² weekly doses. Further dose escalation ceased because of the possibility of severe abnormal LFT changes occurring. DLTs with weekly dosing with lead-in occurred in 1/5 patients at a 56-mg/m² dose; MTD could not be determined because discontinuation criteria for additional enrollment at that particular dose level were met. As no further enrollment at lower doses occurred, dose escalation assessment was discontinued. Serious treatment-related AEs, AEs leading to treatment discontinuation, and DLTs were all related to abnormal LFT changes, suggesting that TAS4464 administration could affect liver function. This effect was dose-dependent but considered reversible. Complete or partial responses to TAS4464 were not observed; one patient achieved prolonged stable disease. Conclusions MTD could not be determined due to TAS4464 effects on liver function. Further evaluation of the mechanism of NEDD8-activating enzyme inhibitor-induced abnormal liver function is required. Trial registration number JapicCTI-173,488 (registered with Japan Pharmaceutical Information Center). Registration date 13 January 2017

An across-breed validation study of 46 genetic markers in canine hip dysplasia

Background

Canine hip dysplasia (CHD) is a common disease, with a complex genetic background. Dogs with severe CHD sometimes also suffer from osteoarthritis (OA), an inflammatory, often painful and incurable condition. Previous studies have reported breed-specific genetic loci associated with different hip dysplasia and OA phenotypes. However, the independent replication of the known associations within or across breeds has been difficult due to variable phenotype measures, inadequate sample sizes and the existence of population specific variants.

Results

We execute a validation study of 46 genetic markers in a cohort of nearly 1600 dogs from ten different breeds. We categorize the dogs into cases and controls according to the hip scoring system defined by the Fédération Cynologique Internationale (FCI). We validate 21 different loci associated on fourteen chromosomes. Twenty of these associated with CHD in specific breeds, whereas one locus is unique to the across-breed study. We show that genes involved in the neddylation pathway are enriched among the genes in the validated loci. Neddylation contributes to many cellular functions including inflammation.

Conclusions

Our study successfully replicates many loci and highlights the complex genetic architecture of CHD. Further characterisation of the associated loci could reveal CHD-relevant genes and pathways for improved understanding of the disease pathogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07375-x.

Diverse and pivotal roles of neddylation in metabolism and immunity

Neddylation is one type of protein post-translational modification by conjugating a ubiquitin-like protein neural precursor cell-expressed developmentally downregulated protein 8 to substrate proteins via a cascade involving E1, E2, and E3 enzymes. The best-characterized substrates of neddylation are cullins, essential components of cullin-RING E3 ubiquitin-ligase complexes. The discovery of noncullin neddylation targets indicates that neddylation may have diverse biological functions. Indeed, neddylation has been implicated in various cellular processes including cell cycle progression, metabolism, immunity, and tumorigenesis. Here, we summarized the reported neddylation substrates and also discuss the functions of neddylation in the immune system and metabolism.

Approaching Inflammation Paradoxes-Proinflammatory Cytokine Blockages Induce Inflammatory Regulators

The mechanisms that underlie various inflammation paradoxes, metabolically healthy obesity, and increased inflammations after inflammatory cytokine blockades and deficiencies remain poorly determined. We performed an extensive -omics database mining, determined the expressions of 1367 innate immune regulators in 18 microarrays after deficiencies of 15 proinflammatory cytokines/regulators and eight microarray datasets of patients receiving Mab therapies, and made a set of significant findings: 1) proinflammatory cytokines/regulators suppress the expressions of innate immune regulators; 2) upregulations of innate immune regulators in the deficiencies of IFNγ/IFNγR1, IL-17A, STAT3 and miR155 are more than that after deficiencies of TNFα, IL-1β, IL-6, IL-18, STAT1, NF-kB, and miR221; 3) IFNγ, IFNγR and IL-17RA inhibit 10, 59 and 39 proinflammatory cytokine/regulator pathways, respectively; in contrast, TNFα, IL-6 and IL-18 each inhibits only four to five pathways; 4) The IFNγ-promoted and -suppressed innate immune regulators have four shared pathways; the IFNγR1-promoted and -suppressed innate immune regulators have 11 shared pathways; and the miR155-promoted and -suppressed innate immune regulators have 13 shared pathways, suggesting negative-feedback mechanisms in their conserved regulatory pathways for innate immune regulators; 5) Deficiencies of proinflammatory cytokine/regulator-suppressed, promoted programs share signaling pathways and increase the likelihood of developing 11 diseases including cardiovascular disease; 6) There are the shared innate immune regulators and pathways between deficiency of TNFα in mice and anti-TNF therapy in clinical patients; 7) Mechanistically, up-regulated reactive oxygen species regulators such as myeloperoxidase caused by suppression of proinflammatory cytokines/regulators can drive the upregulation of suppressed innate immune regulators. Our findings have provided novel insights on various inflammation paradoxes and proinflammatory cytokines regulation of innate immune regulators; and may re-shape new therapeutic strategies for cardiovascular disease and other inflammatory diseases.

Neddylation: A Versatile Pathway Takes on Chronic Liver Diseases

Neddylation is a ubiquitin-like posttranslational modification that conjugates neural precursor cell expressed developmentally downregulated-8 (Nedd8) to specific substrates for regulation of protein activity. In light of current researches, the neddylation pathway is aberrant in the pathogenesis of many diseases. In our review, we summarize the versatile roles of neddylation in chronic liver diseases (CLDs). CLDs are one of the leading causes of chronic disease-associated deaths worldwide. There are diverse etiologic agents causing CLDs, mainly including hepatitis B virus (HBV) infection, nonalcoholic fatty liver disease (NAFLD), chronic exposure to alcohol or drugs, and autoimmune causes. So far, however, there remains a paucity of effective therapeutic approach to CLDs. In this review, we summarized the role of the neddylation pathway which runs through the chronic hepatitis B/NAFLD-liver fibrosis-cirrhosis-hepatocellular carcinoma (HCC) axis, a canonical pattern in the process of CLD development and progression. The dysregulation of neddylation may provide a better understanding of CLD pathology and even a novel therapeutic strategy. Correspondingly, inhibiting neddylation via MLN4924, a small molecule compound targeting NEDD8-activating enzyme (NAE), can potently alleviate CLD progression and improve the outcome. On this basis, profiling and characterization of the neddylation pathway can provide new insights into the CLD pathology as well as novel therapeutic strategies, independently of the etiology of CLD.

The pivotal roles of neddylation pathway in immunoregulation

Introduction

Protein neddylation, one of the most important posttranslational modifications that tagging neuronal precursor cell‐expressed developmentally downregulated protein 8 onto substrate proteins, plays fundamental roles in the process of many cellular functions. A number of studies have demonstrated the critical roles of neddylation modification in multiple pathophysiological processes, but its regulatory role in the immune system has only been finitely unveiled.

Methods

In this review, the latest advances in the field of neddylation modification in regulating the immune responses are succinctly discussed.

Results

Neddylation modification acts as a crucial modulator of innate immune cells (neutrophils, macrophages, and dendritic cells) and lymphocytes. Dysregulation of neddylation alters characteristics and functions of those cells due to abnormal degradation of key signaling molecules involved in immunoregulation. Furthermore, the ectopic immune responses caused by the abnormal neddylation play pivotal roles in a variety of immune‐related diseases, such as infection, inflammation, and cancer.

Conclusions

The pivotal roles of neddylation pathway in immunoregulation are attracted more and more attention, which may provide new insights into the pathogenesis of a variety of immune‐related diseases and help to indicate new therapeutic targets and potential treatment strategies.

Lipin-2 degradation elicits a proinflammatory gene signature in macrophages

Lipin-2 is a phosphatidate phosphatase with key roles in regulating lipid storage and energy homeostasis. LPIN2-genetic deficiency is associated with an autoinflammatory disorder, underscoring its critical role in innate immune signaling; however, the regulatory mechanisms underlying protein stability remain unknown. Here, we demonstrate that Lipin-2 interacts with β-TRCP, a substrate receptor subunit of the SCF^β-TRCP E3 ligase, and undergoes ubiquitination and proteasomal degradation. β-TRCP-knockout in RAW264.7 macrophages resulted in Lipin-2 accumulation, leading to the suppression of LPS-induced MAPK activation and subsequent proinflammatory gene expression. Consistent with this, treatment with MLN4924, a Cullin-neddylation inhibitor that suppresses SCF E3 activity, increased Lipin-2 protein and concomitantly decreased Il1b expression. These findings suggested that β-TRCP-mediated Lipin-2 degradation affects macrophage-elicited proinflammatory responses and could lead to new therapeutic approaches to treat inflammatory diseases.

Targeting Protein Neddylation for Cancer Therapy

Neddylation is a posttranslational modification that conjugates a ubiquitin-like protein NEDD8 to substrate proteins. The best-characterized substrates of neddylation are the cullin subunits of cullin-RING E3 ubiquitin ligase complexes (CRLs). CRLs as the largest family of E3 ubiquitin ligases control many important biological processes, including tumorigenesis, through promoting ubiquitylation and subsequent degradation of a variety of key regulatory proteins. The process of protein neddylation is overactivated in multiple types of human cancers, providing a sound rationale as an attractive anticancer therapeutic strategy, evidenced by the development of the NEDD8-activating enzyme (NAE) inhibitor MLN4924 (also known as pevonedistat). Recently, increasing evidence strongly indicates that neddylation inhibition by MLN4924 exerts anticancer effects mainly by triggering cell apoptosis, senescence, and autophagy and causing angiogenesis suppression, inflammatory responses, and chemo-/radiosensitization in a context-dependent manner. Here, we briefly summarize the latest progresses in this field, focusing on the preclinical studies to validate neddylation modification as a promising anticancer target.

Neddylation Facilitates the Antiviral Response in Zebrafish

Neddylation is a type of post-translational protein modifications, in which neural precursor cell expressed developmentally downregulated protein 8 (NEDD8) is covalently conjugated to the lysine residues of target substrates. The best characterized principal substrates of neddylation are the cullin-RING ligases (CRLs). In addition, neddylation also modifies non-cullin proteins to affect gene regulation, cell survival, organ development, and stress response. However, the role of neddylation in antiviral innate immunity remain largely unknown. Here, we found that when neddylation was blocked by the NEDD8 activating enzyme E1 (NAE) inhibitor, MLN4924, the cellular and organismal antiviral response was suppressed. Moreover, the disruption of nedd8 increased the sensitivity of zebrafish to SVCV infection. Further assays indicated that blocking or silencing neddylation significantly downregulated key antiviral genes after poly (I:C) stimulation or SVCV infection, but dramatically increased SVCV replication. Neddylation of Irf3 and Irf7 was readily detected, but not of Mda5, Mavs, and Tbk1. Thus, our results not only demonstrated that neddylation facilitated the antiviral response in vitro and in vivo, but also revealed a novel role of nedd8 in antiviral innate immunity.

Role of the COP9 Signalosome (CSN) in Cardiovascular Diseases

The constitutive photomorphogenesis 9 (COP9) signalosome (CSN) is an evolutionarily conserved multi-protein complex, consisting of eight subunits termed CSN1-CSN8. The main biochemical function of the CSN is the control of protein degradation via the ubiquitin-proteasome-system through regulation of cullin-RING E3-ligase (CRL) activity by deNEDDylation of cullins, but the CSN also serves as a docking platform for signaling proteins. The catalytic deNEDDylase (isopeptidase) activity of the complex is executed by CSN5, but only efficiently occurs in the three-dimensional architectural context of the complex. Due to its positioning in a central cellular pathway connected to cell responses such as cell-cycle, proliferation, and signaling, the CSN has been implicated in several human diseases, with most evidence available for a role in cancer. However, emerging evidence also suggests that the CSN is involved in inflammation and cardiovascular diseases. This is both due to its role in controlling CRLs, regulating components of key inflammatory pathways such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and complex-independent interactions of subunits such as CSN5 with inflammatory proteins. In this case, we summarize and discuss studies suggesting that the CSN may have a key role in cardiovascular diseases such as atherosclerosis and heart failure. We discuss the implicated molecular mechanisms ranging from inflammatory NF-κB signaling to proteotoxicity and necrosis, covering disease-relevant cell types such as myeloid and endothelial cells or cardiomyocytes. While the CSN is considered to be disease-exacerbating in most cancer entities, the cardiovascular studies suggest potent protective activities in the vasculature and heart. The underlying mechanisms and potential therapeutic avenues will be critically discussed.

Bacterial flagellin promotes viral entry via an NF-kB and Toll Like Receptor 5 dependent pathway

Viruses and bacteria colonize hosts by invading epithelial barriers. Recent studies have shown that interactions between the microbiota, pathogens and the host can potentiate infection through poorly understood mechanisms. Here, we investigated whether diverse bacterial species could modulate virus internalization into host cells, often a rate-limiting step in establishing infections. Lentiviral pseudoviruses expressing influenza, measles, Ebola, Lassa or vesicular stomatitis virus envelope glycoproteins enabled us to study entry of viruses that exploit diverse internalization pathways. Salmonella Typhimurium, Escherichia coli and Pseudomonas aeruginosa significantly increased viral uptake, even at low bacterial frequencies. This did not require bacterial contact with or invasion of host cells. Studies determined that the bacterial antigen responsible for this pro-viral activity was the Toll-Like Receptor 5 (TLR5) agonist flagellin. Exposure to flagellin increased virus attachment to epithelial cells in a temperature-dependent manner via TLR5-dependent activation of NF-ΚB. Importantly, this phenotype was both long lasting and detectable at low multiplicities of infection. Flagellin is shed from bacteria and our studies uncover a new bystander role for this protein in regulating virus entry. This highlights a new aspect of viral-bacterial interplay with significant implications for our understanding of polymicrobial-associated pathogenesis.

Inhibition of neddylation plays protective role in lipopolysaccharide-induced kidney damage through CRL-mediated NF-κB pathways

It has been shown that NF-κB signaling path is very effective pharmacological target for the treatment of various inflammatory diseases, including bacterial infection-associated acute kidney injury (AKI), which remains a main cause of disability and death in patients. Notably, IκB, the upstream molecular of NF-κB, plays an important role by inhibiting NF-κB activity, and IκB is regulated by cullin-RING E3 ligases (CRLs)-mediated proteasomal degradation. Therefore inhibition of CRLs-mediated neddylation and degradation of IκB would prevent NF-κB-mediated inflammation. MLN4924, a potent neddylation-inhibiting pharmacological agent, has been shown to have significant protective effects against lipopolysaccharide (LPS)-induced pro-inflammatory cytokine production through restriction of the CRL-mediated NF-κB pathway. However, it is still unclear whether MLN4924 plays a protective role through its anti-inflammatory properties in sepsis-induced AKI. In the current research, we explored whether MLN4924 have anti-inflammatory action in LPS-induced AKI mice. Our results show that MLN4924 dramatically decreased the cytotoxicity of LPS and inhibited LPS-induced synthesis and release of pro-inflammatory cytokines, such as TNF-α, IL-6 and IL-1β, in HK2 cells, a renal tubular cell line. In addition, MLN4924 inhibited Nedd8-activating enzymes, which broke the process of cullin proteins neddylation and subsequent CRL target proteins degradation. The MLN4924-induced degradation of CRL attenuated the phosphorylation modification of IκB and IKK-α/β and blocked the nuclear translocation of P50-NF-κB and P65-NF-κB in HK2 cells under LPS stimulation. Finally, our in vivo results show that MLN4924 protected against LPS-induced AKI at relatively low doses. Collectively, these results suggest that pharmacologically blocking neddylation by MLN4924 results in the suppression of pro-inflammatory cytokines generation through the CRL/NF-κB pathway in LPS-stimulated HK2 cells, and attenuated renal inflammation in LPS-induced AKI.

MLN4924 Exerts a Neuroprotective Effect against Oxidative Stress via Sirt1 in Spinal Cord Ischemia-Reperfusion Injury

Oxidative stress is a leading contributor to spinal cord ischemia-reperfusion (SCIR) injury. Recently, MLN4924, a potent and selective inhibitor of the NEDD8-activating enzyme, was shown to exert a neuroprotective effect against oxidative stress in vitro. However, it is unknown whether MLN4924 plays a protective role against SCIR injury. In the present study, we found that MLN4924 treatment significantly attenuated oxidative stress and neuronal cell death induced by H₂O₂ in SH-SY-5Y neural cells and during rat SCIR injury. Furthermore, MLN4924 administration restored neurological and motor functions in rats with SCIR injury. Mechanistically, we found that MLN4924 protects against H₂O₂- and SCIR injury-induced neurodegeneration by regulating sirtuin 1 (Sirt1) expression. Collectively, these findings demonstrate the neuroprotective role of MLN4924 against oxidative stress in SCIR injury via Sirt1.

Neddylation: a novel modulator of the tumor microenvironment

Neddylation, a post-translational modification that adds an ubiquitin-like protein NEDD8 to substrate proteins, modulates many important biological processes, including tumorigenesis. The process of protein neddylation is overactivated in multiple human cancers, providing a sound rationale for its targeting as an attractive anticancer therapeutic strategy, as evidence by the development of NEDD8-activating enzyme (NAE) inhibitor MLN4924 (also known as pevonedistat). Neddylation inhibition by MLN4924 exerts significantly anticancer effects mainly by triggering cell apoptosis, senescence and autophagy. Recently, intensive evidences reveal that inhibition of neddylation pathway, in addition to acting on tumor cells, also influences the functions of multiple important components of the tumor microenvironment (TME), including immune cells, cancer-associated fibroblasts (CAFs), cancer-associated endothelial cells (CAEs) and some factors, all of which are crucial for tumorigenesis. Here, we briefly summarize the latest progresses in this field to clarify the roles of neddylation in the TME, thus highlighting the overall anticancer efficacy of neddylaton inhibition.

MLN4924 protects against interleukin-17A-induced pulmonary inflammation by disrupting ACT1-mediated signaling

An excessive inflammatory response in terminal airways, alveoli, and the lung interstitium eventually leads to pulmonary hypertension and chronic obstructive pulmonary disease. Proinflammatory cytokine interleukin-17A (IL-17A) has been implicated in the pathogenesis of pulmonary inflammatory diseases. MLN4924, an inhibitor of NEDD8-activating enzyme (NAE), is associated with the treatment of various types of cancers, but its role in the IL-17A-mediated inflammatory response has not been identified. Here, we report that MLN4924 can markedly reduce the expression of proinflammatory cytokines and chemokines such as IL-1β, IL-6, and CXCL-1 and neutrophilia in a mouse model of IL-17A adenovirus-induced pulmonary inflammation. MLN4924 significantly inhibited IL-17A-induced stabilization of mRNA of proinflammatory cytokines and chemokines in vitro. Mechanistically, MLN4924 significantly blocked the activation of MAPK and NF-κB pathways and interfered with the interaction between ACT1 and tumor necrosis factor receptor-associated factor proteins (TRAFs), thereby inhibiting TRAF6 ubiquitination. Taken together, our data uncover a previously uncharacterized inhibitory effect of MLN4924 on the IL-17A-mediated inflammatory response; this phenomenon may facilitate the development of MLN4924 into an effective small-molecule drug for the treatment of pulmonary inflammatory diseases.

TRAF6 neddylation drives inflammatory arthritis by increasing NF-κB activation

Neddylation is a process similar to ubiquitination, and is critical in various inflammatory diseases; however, its importance in the pathogenesis of inflammatory arthritis is not well understood. Here, we investigated the role of neddylation in collagen-induced arthritis (CIA) and its clinical relevance. We showed that neddylation-related genes, including NEDD8 and CULLIN-1, were significantly upregulated in inflamed arthritic synovia. Functionally, neddylation activation was crucial for synovitis of CIA, as the inhibition of neddylation by MLN4924 significantly suppressed synovial cell proliferation and inflammatory responses. Mechanistically, neddylation mediated inflammatory arthritis by regulating NF-κB activation in fibroblast-like synovial cells (FLSs). Furthermore, TNF receptor-associated factor 6 (TRAF6) neddylation at Lys124 was essential for IL-17A-induced NF-κB activation. Replacing the Lys-124 residue with Arg (K124R) resulted in significantly impaired conjugation of NEDD8 to TRAF6, as well as markedly attenuated IL-17A-induced NF-κB activity. Therefore, the pathogenic role of neddylation in CIA as well as its mechanism of action demonstrated here provides a new insight into understanding the role of post-transcriptional modifications in the arthritis inflammatory response.