The deubiquitinase OTUD1 regulates immunoglobulin production and proteasome inhibitor sensitivity in multiple myeloma

OTUD1 Deficiency Alleviates LPS-Induced Acute Lung Injury in Mice by Reducing Inflammatory Response

The ovarian tumor (OTU) family consists of deubiquitinating enzymes thought to play a crucial role in immunity. Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) pose substantial clinical challenges due to severe respiratory complications and high mortality resulting from uncontrolled inflammation. Despite this, no study has explored the potential link between the OTU family and ALI/ARDS. Using publicly available high-throughput data, 14 OTUs were screened in a simulating bacteria- or LPS-induced ALI model. Subsequently, gene knockout mice and transcriptome sequencing were employed to explore the roles and mechanisms of the selected OTUs in ALI. Our screen identified OTUD1 in the OTU family as a deubiquitinase highly related to ALI. In the LPS-induced ALI model, deficiency of OTUD1 significantly ameliorated pulmonary edema, reduced permeability damage, and decreased lung immunocyte infiltration. Furthermore, RNA-seq analysis revealed that OTUD1 deficiency inhibited key pathways, including the IFN-γ/STAT1 and TNF-α/NF-κB axes, ultimately mitigating the severity of immune responses in ALI. In summary, our study highlights OTUD1 as a critical immunomodulatory factor in acute inflammation. These findings suggest that targeting OTUD1 could hold promise for the development of novel treatments against ALI/ARDS.

TRIM44 facilitates aggressive behaviors in multiple myeloma through promoting ZEB1 deubiquitination

BACKGROUND

Tripartite motif-containing 44 (TRIM44) involves in various tumor development. This study investigated role of TRIM44 in multiple myeloma (MM).

MATERIALS AND METHODS

TRIM44 levels in bone marrow tissues and MM cell lines was detected by quantitative reverse transcription PCR (RT-qPCR). Cell viability, migration, and invasion of MM cells were evaluated under the interference of TRIM44 expression. The role of TRIM44 on regulating tumor growth in vivo was also investigated in subcutaneous tumor xenograft models. The protein interact between TRIM44 and Zinc Finger E-Box Binding Homeobox 1 (ZEB1) was also studied according IP followed by western blotting assay.

RESULTS

TRIM44 was all highly expressed in collected bone marrow tissues and MM cell lines. Cell viability, migration, and invasion of MM cells with low expression of TRIM44 was significantly inhibited. Over-expression of TRIM44 can down-regulate the ZEB1 ubiquitination to enhance the protein stability.

CONCLUSIONS

TRIM44 exerts as an oncogenic factor to induce the oncogenesis of MM by stabilizing ZEB1.

Metabolic reprogramming induced by PSMA4 overexpression facilitates bortezomib resistance in multiple myeloma

Multiple myeloma(MM) remains incurable with high relapse and chemoresistance rates. Differentially expressed genes(DEGs) between newly diagnosed myeloma and secondary plasma cell leukemia(sPCL) were subjected to a weighted gene co-expression network analysis(WGCNA). Drug resistant myeloma cell lines were established. Seahorse XF analyzer was applied to detect the metabolism reprogramming associated with the hub gene. The metabolic relevance and the underlying mechanism of the hub gene in myeloma resistance were explored via in vitro experiments. A total of 1310 DEGs were used to construct five co-expression modules. Gene function enrichment analysis demonstrated that candidate hub genes were closely related to oxidative phosphorylation. We performed prognostic analysis and identified PSMA4 as the key hub gene related to the extramedullary invasion of myeloma. The in vitro experiments demonstrated bortezomib resistant myeloma cell lines exhibited high PSMA4 expression, improved oxidative phosphorylation activity with increased ROS level. PSMA4 knockdown re-sensitize resistant myeloma cells via suppressing oxidative phosphorylation activity. Further investigation revealed that PSMA4 induced a hypoxia state which activated the HIF-1α signaling pathway. PSMA4 induces metabolic reprogramming by improving oxidative phosphorylation activity which accounts for the hypoxia state in myeloma cell. The activated HIF-1α signaling pathway causes bortezomib resistance via promoting anti-apoptotic activity in myeloma.

A comprehensive review of peroxiredoxin 4, a redox protein evolved in oxidative protein folding coupled with hydrogen peroxide detoxification

Peroxiredoxin (PRDX) primarily employs electrons from thioredoxin in order to reduce peroxides. PRDX4 mainly resides either in the endoplasmic reticulum (ER) lumen or in extracellular spaces. Due to the usage of alternative promoters, a first exon is transcribed from different regions of the Prdx4 gene, which results in two types of mRNAs. The first type is designated as Prdx4. It is translated with a cleavable, hydrophobic signal sequence and is expressed in most cells throughout the body. The second type is designated as Prdx4t. The peroxidase activity of PRDX4 is involved in both the reduction of hydrogen peroxides and in the oxidative folding of nascent proteins in the ER. Prdx4 appears to have evolved from an ancestral gene in Eutherians simultaneously with the evolution of sperm protamine to cysteine-rich peptides, and, therefore, the testis-specific PRDX4t is likely involved in spermatogenesis through the oxidative folding of protamine. The dysfunction of PRDX4 leads to oxidative damage and ER stress, and is related to various diseases including diabetes and cancer. In this review article we refer to the results of biological and medical research in order to unveil the functional consequences of this unique member of the PRDX family.

KEAP1-NRF2 Interaction in Cancer: Competitive Interactors and Their Role in Carcinogenesis

An American Cancer Society report estimates the emergence of around 2 million new cancer cases in the US in 2024 [...].

Beyond the marrow: insights from comprehensive next-generation sequencing of extramedullary multiple myeloma tumors

Extramedullary multiple myeloma (EMM) is an aggressive form of multiple myeloma (MM). This study represents the most comprehensive next-generation sequencing analysis of EMM tumors (N = 14) to date, uncovering key molecular features and describing the tumor microenvironment. We observed the co-occurrence of 1q21 gain/amplification and MAPK pathway mutations in 79% of EMM samples, suggesting that these are crucial mutational events in EMM development. We also demonstrated that patients with mutated KRAS and 1q21 gain/amplification at the time of diagnosis have a significantly higher risk of EMM development (HR = 2.4, p = 0.011) using data from a large CoMMpass dataset. We identified downregulation of CXCR4 and enhanced cell proliferation, along with reduced expression of therapeutic targets (CD38, SLAMF7, GPRC5D, FCRH5), potentially explaining diminished efficacy of immunotherapy. Conversely, we identified significantly upregulated EZH2 and CD70 as potential future therapeutic options. For the first time, we report on the tumor microenvironment of EMM, revealing CD8+ T cells and NK cells as predominant immune effector cells using single-cell sequencing. Finally, this is the first longitudinal study in EMM revealing the molecular changes from the time of diagnosis to EMM relapse.

OTUD1 promotes hypertensive kidney fibrosis and injury by deubiquitinating CDK9 in renal epithelial cells

Hypertensive renal disease (HRD) contributes to the progression of kidney dysfunction and ultimately leads to end-stage renal disease. Understanding the mechanisms underlying HRD is critical for the development of therapeutic strategies. Deubiquitinating enzymes (DUBs) have been recently highlighted in renal pathophysiology. In this study, we investigated the role of a DUB, OTU Domain-Containing Protein 1 (OTUD1), in HRD models. HRD was induced in wild-type or Otud1 knockout mice by chronic infusion of angiotensin II (Ang II, 1 μg/kg per min) through a micro-osmotic pump for 4 weeks. We found that OTUD1 expression levels were significantly elevated in the kidney tissues of Ang II-treated mice. Otud1 knockout significantly ameliorated Ang II-induced HRD, whereas OTUD1 overexpression exacerbated Ang II-induced kidney damage and fibrosis. Similar results were observed in TCMK-1 cells but not in SV40 MES-13 cells following Ang II (1 μM) treatment. In Ang II-challenged TCMK-1 cells, we demonstrated that OTUD1 bound to CDK9 and induced CDK9 deubiquitination: OTUD1 catalyzed K63 deubiquitination on CDK9 with its Cys320 playing a critical role, promoting CDK9 phosphorylation and activation to induce inflammatory responses and fibrosis in kidney epithelial cells. Administration of a CDK9 inhibitor NVP-2 significantly ameliorated Ang II-induced HRD in mice. This study demonstrates that OTUD1 mediates HRD by targeting CDK9 in kidney epithelial cells, suggesting OTUD1 is a potential target in treating this disease.

MUC20 regulated by extrachromosomal circular DNA attenuates proteasome inhibitor resistance of multiple myeloma by modulating cuproptosis

BACKGROUND

Proteasome inhibitors (PIs) are one of the most important classes of drugs for the treatment of multiple myeloma (MM). However, almost all patients with MM develop PI resistance, resulting in therapeutic failure. Therefore, the mechanisms underlying PI resistance in MM require further investigation.

METHODS

We used several MM cell lines to establish PI-resistant MM cell lines. We performed RNA microarray and EccDNA-seq in MM cell lines and collected human primary MM samples to explore gene profiles. We evaluated the effect of MUC20 on cuproptosis of PI-resistant MM cells using Co-immunoprecipitation (Co-IP), Seahorse bioenergetic profiling and in vivo assay.

RESULTS

This study revealed that the downregulation of Mucin 20 (MUC20) could predict PI sensitivity and outcomes in MM patients. Besides, MUC20 attenuated PI resistance in MM cells by inducing cuproptosis via the inhibition of cyclin-dependent kinase inhibitor 2 A expression (CDKN2A), which was achieved by hindering MET proto-oncogene, receptor tyrosine kinase (MET) activation. Moreover, MUC20 suppressed MET activation by repressing insulin-like growth factor receptor-1 (IGF-1R) lactylation in PI-resistant MM cells. This study is the first to perform extrachromosomal circular DNA (eccDNA) sequencing for MM, and it revealed that eccDNA induced PI resistance by amplifying kinesin family member 3 C (KIF3C) to reduce MUC20 expression in MM.

CONCLUSION

Our findings indicated that MUC20 regulated by eccDNA alleviates PI resistance of MM by modulating cuproptosis, which would provide novel strategies for the treatment of PI-resistant MM.

Factors determining the sensitivity to proteasome inhibitors of multiple myeloma cells

Multiple myeloma is an incurable cancer that originates from antibody-producing plasma cells. It is characterized by an intrinsic ability to produce large amounts of immunoglobulin-like proteins. The high rate of synthesis makes myeloma cells dependent on protein processing mechanisms related to the proteasome. This dependence made proteasome inhibitors such as bortezomib and carfilzomib one of the most important classes of drugs used in multiple myeloma treatment. Inhibition of the proteasome is associated with alteration of a number of important biological processes leading, in consequence, to inhibition of angiogenesis. The effect of drugs in this group and the degree of patient response to the treatment used is itself an extremely complex process that depends on many factors. At cellular level the change in sensitivity to proteasome inhibitors may be related to differences in the expression level of proteasome subunits, the degree of proteasome loading, metabolic adaptation, transcriptional or epigenetic factors. These are just some of the possibilities that may influence differences in response to proteasome inhibitors. This review describes the main cellular factors that determine the degree of response to proteasome inhibitor drugs, as well as information on the key role of the proteasome and the performance characteristics of the inhibitors that are the mainstay of multiple myeloma treatment.

The Deubiquitinase OTUD1 Suppresses Secretory Neutrophil Polarization And Ameliorates Immunopathology of Periodontitis

Tissue-infiltrating neutrophils (TINs) secrete various signaling molecules to establish paracrine communication within the inflammatory milieu. It is imperative to identify molecular mediators that control this secretory phenotype of TINs. The present study uncovers a secretory neutrophil subset that exhibits increased pro-inflammatory cytokine production and enhanced migratory capacity which is highly related with periodontal pathogenesis. Further analysis identifies the OTU domain-containing protein 1 (OTUD1) plays a regulatory role in this secretory neutrophil polarization. In human and mouse periodontitis, the waning of inflammation is correlated with OTUD1 upregulation, whereas severe periodontitis is induced when neutrophil-intrinsic OTUD1 is depleted. Mechanistically, OTUD1 interacts with SEC23B, a component of the coat protein II complex (COPII). By removing the K63-linked polyubiquitin chains on SEC23B Lysine 81, the deubiquitinase OTUD1 negatively regulates the COPII secretory machinery and limits protein ER-to-Golgi trafficking, thus restricting the surface expression of integrin-regulated proteins, CD9 and CD47. Accordingly, blockade of protein transport by Brefeldin A (BFA) curbs recruitment of Otud1-deficient TINs and attenuates inflammation-induced alveolar bone destruction. The results thus identify OTUD1 signaling as a negative feedback loop that limits the polarization of neutrophils with secretory phenotype and highlight the potential application of BFA in the treatment of periodontal inflammation.

The pro-tumorigenic cytokine IL-32 has a high turnover in multiple myeloma cells due to proteolysis regulated by oxygen-sensing cysteine dioxygenase and deubiquitinating enzymes

IL-32 is a pro-inflammatory cytokine expressed by several types of cancer cells and immune cells. Currently, no treatment targeting IL-32 is available, and its intracellular and exosomal localization make IL-32 less accessible to drugs. We previously showed that hypoxia promotes IL-32 expression through HIF1α in multiple myeloma cells. Here, we demonstrate that high-speed translation and ubiquitin-dependent proteasomal degradation lead to a rapid IL-32 protein turnover. We find that IL-32 protein half-life is regulated by the oxygen-sensing cysteine-dioxygenase ADO and that deubiquitinases actively remove ubiquitin from IL-32 and promote protein stability. Deubiquitinase inhibitors promoted the degradation of IL-32 and may represent a strategy for reducing IL-32 levels in multiple myeloma. The fast turnover and enzymatic deubiquitination of IL-32 are conserved in primary human T cells; thus, deubiquitinase inhibitors may also affect T-cell responses in various diseases.

New insights into the roles of peroxiredoxins in cancer

Oxidative stress is one of the hallmarks of cancer. Tumorigenesis and progression are accompanied by elevated reactive oxygen species (ROS) levels and adaptive elevation of antioxidant expression levels. Peroxiredoxins (PRDXs) are among the most important antioxidants and are widely distributed in a variety of cancers. PRDXs are involved in the regulation of a variety of tumor cell phenotypes, such as invasion, migration, epithelial-mesenchymal transition (EMT) and stemness. PRDXs are also associated with tumor cell resistance to cell death, such as apoptosis and ferroptosis. In addition, PRDXs are involved in the transduction of hypoxic signals in the TME and in the regulation of the function of other cellular components of the TME, such as cancer-associated fibroblasts (CAFs), natural killer (NK) cells and macrophages. This implies that PRDXs are promising targets for cancer treatment. Of course, further studies are needed to realize the clinical application of targeting PRDXs. In this review, we highlight the role of PRDXs in cancer, summarizing the basic features of PRDXs, their association with tumorigenesis, their expression and function in cancer, and their relationship with cancer therapeutic resistance.

Combinations of ivermectin with proteasome inhibitors induce synergistic lethality in multiple myeloma

Multiple myeloma (MM) is an incurable malignancy of plasma cells. Ivermectin is a US Food and Drug Administration-approved drug for antiparasitic use. Here, we showed that ivermectin exerted anti-MM effects and significantly synergized with proteasome inhibitors in vitro and in vivo. Ivermectin alone exhibited mild anti-MM activity in vitro. Further investigation suggested that ivermectin inhibited proteasome activity in the nucleus by repressing the nuclear import of proteasome subunits, such as PSMB5-7 and PSMA3-4. Therefore, ivermectin treatment caused the accumulation of ubiquitylated proteins and the activation of the UPR pathway in MM cells. Furthermore, ivermectin treatment caused DNA damage and DNA damage response (DDR) signaling pathway activation in MM cells. Ivermectin and bortezomib exhibited synergized anti-MM activity in vitro. The dual-drug treatment resulted in synergistic inhibition of proteasome activity and increased DNA damage. An in vivo study using a human MM cell line xenograft mouse model showed that ivermectin and bortezomib efficiently repressed MM tumor growth in vivo, while the dual-drug treatment was well tolerated by experimental animals. Overall, our results demonstrated that ivermectin alone or cotreated with bortezomib might be promising in MM treatment.

Pleiotropic Roles of a KEAP1-Associated Deubiquitinase, OTUD1

Protein ubiquitination, which is catalyzed by ubiquitin-activating enzymes, ubiquitin-conjugating enzymes, and ubiquitin ligases, is a crucial post-translational modification to regulate numerous cellular functions in a spatio-temporal-specific manner. The human genome encodes ~100 deubiquitinating enzymes (DUBs), which antagonistically regulate the ubiquitin system. OTUD1, an ovarian tumor protease (OTU) family DUB, has an N-terminal-disordered alanine-, proline-, glycine-rich region (APGR), a catalytic OTU domain, and a ubiquitin-interacting motif (UIM). OTUD1 preferentially hydrolyzes lysine-63-linked ubiquitin chains in vitro; however, recent studies indicate that OTUD1 cleaves various ubiquitin linkages, and is involved in the regulation of multiple cellular functions. Thus, OTUD1 predominantly functions as a tumor suppressor by targeting p53, SMAD7, PTEN, AKT, IREB2, YAP, MCL1, and AIF. Furthermore, OTUD1 regulates antiviral signaling, innate and acquired immune responses, and cell death pathways. Similar to Nrf2, OTUD1 contains a KEAP1-binding ETGE motif in its APGR and regulates the reactive oxygen species (ROS)-mediated oxidative stress response and cell death. Importantly, in addition to its association with various cancers, including multiple myeloma, OTUD1 is involved in acute graft-versus-host disease and autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, and ulcerative colitis. Thus, OTUD1 is an important DUB as a therapeutic target for a variety of diseases.