RNF115 Inhibits the Post-ER Trafficking of TLRs and TLRs-Mediated Immune Responses by Catalyzing K11-Linked Ubiquitination of RAB1A and RAB13

Analysis of TLR10 gene polymorphisms in patients with rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a chronic systemic disease characterized by inflammatory synovitis, and genetic factors play the greatest role in RA. This study aimed to investigate the relationship between Toll-like receptor 10(TLR10) gene polymorphisms and susceptibility to RA.

METHODS

A total of 271 patients with RA and an equal number of healthy controls were included, and the TLR10 rs2101521, rs10004195 and rs11725309 loci were genotyped by time-of-flight mass spectrometry.

RESULTS

Compared with healthy controls, Individuals carrying the rs2101521 G allele had an increased risk of developing RA (P = 0.01; odds ratio (OR) = 1.367; 95 % confidence interval (CI): 1.076-1.736). Individuals with the rs2101521 GG genotype had a greater risk of RA (P = 0.01; OR = 1.816; 95 % CI: 1.161-2.984). Stratified analysis demonstrated a greater prevalence of positive anti-cyclic citrullinated peptide (CCP)antibody in patients carrying the rs2101521 G allele (P = 0.03). Additionally, patients with the rs11725309 CT genotype had elevated levels of C-reactive protein (CRP)(P = 0.007).

CONCLUSION

In conclusion, TLR10 gene polymorphisms are associated with RA susceptibility.

Rab GTPases, Active Members in Antigen-Presenting Cells, and T Lymphocytes

Processes such as cell migration, phagocytosis, endocytosis, and exocytosis refer to the intense exchange of information between the internal and external environment in the cells, known as vesicular trafficking. In eukaryotic cells, these essential cellular crosstalks are controlled by Rab GTPases proteins through diverse adaptor proteins like SNAREs complex, coat proteins, phospholipids, kinases, phosphatases, molecular motors, actin, or tubulin cytoskeleton, among others, all necessary for appropriate mobilization of vesicles and distribution of molecules. Considering these molecular events, Rab GTPases are critical components in specific biological processes of immune cells, and many reports refer primarily to macrophages; therefore, in this review, we address specific functions in immune cells, concretely in the mechanism by which the GTPase contributes in dendritic cells (DCs) and, T/B lymphocytes.

E3 ubiquitin ligase BCA2 promotes breast cancer stemness by up-regulation of SOX9 by LPS

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer. Breast cancer stem cells (BCSCs) are believed to play a crucial role in the carcinogenesis, therapy resistance, and metastasis of TNBC. It is well known that inflammation promotes stemness. Several studies have identified breast cancer-associated gene 2 (BCA2) as a potential risk factor for breast cancer incidence and prognosis. However, whether and how BCA2 promotes BCSCs has not been elucidated. Here, we demonstrated that BCA2 specifically promotes lipopolysaccharide (LPS)-induced BCSCs through LPS induced SOX9 expression. BCA2 enhances the interaction between myeloid differentiation primary response protein 88 (MyD88) and Toll-like receptor 4 (TLR4) and inhibits the interaction of MyD88 with deubiquitinase OTUD4 in the LPS-mediated NF-κB signaling pathway. And SOX9, an NF-κB target gene, mediates BCA2's pro-stemness function in TNBC. Our findings provide new insights into the molecular mechanisms by which BCA2 promotes breast cancer and potential therapeutic targets for the treatment of breast cancer.

Molecular characterization of Golgi apparatus-related genes indicates prognosis and immune infiltration in osteosarcoma

BACKGROUND

The Golgi apparatus (GA) is crucial for protein synthesis and modification, and regulates various cellular processes. Dysregulation of GA can lead to pathological conditions like neoplastic growth. GA-related genes (GARGs) mutations are commonly found in cancer, contributing to tumor metastasis. However, the expression and prognostic significance of GARGs in osteosarcoma are yet to be understood.

METHODS

Gene expression and clinical data of osteosarcoma patients were obtained from the TARGET and GEO databases. A consensus clustering analysis identified distinct molecular subtypes based on GARGs. Discrepancies in biological processes and immunological features among the subtypes were explored using GSVA, ssGSEA, and Metascape analysis. A GARGs signature was constructed using Cox regression. The prognostic value of the GARGs signature in osteosarcoma was evaluated using Kaplan-Meier curves and a nomogram.

RESULTS

Two GARG subtypes were identified, with Cluster A showing better prognosis, immunogenicity, and immune cell infiltration than Cluster B. A novel risk model of 3 GARGs was established using the TARGET dataset and validated with independent datasets. High-risk patients had poorer overall survival, and the GARGs signature independently predicted osteosarcoma prognosis. Combining risk scores and clinical characteristics in a nomogram improved prediction performance. Additionally, we discovered Stanniocalcin-2 (STC2) as a significant prognostic gene highly expressed in osteosarcoma and potential disease biomarker.

CONCLUSIONS

Our study revealed that patients with osteosarcoma can be divided into two GARGs subgroups. Furthermore, we have developed a GARGs prognostic signature that can accurately forecast the prognosis of osteosarcoma patients.

Disulfiram ameliorates STING/MITA-dependent inflammation and autoimmunity by targeting RNF115

STING (also known as MITA) is an adaptor protein that mediates cytoplasmic DNA-triggered signaling, and aberrant activation of STING/MITA by cytosolic self-DNA or gain-of-function mutations causes severe inflammation. Here, we show that STING-mediated inflammation and autoimmunity are promoted by RNF115 and alleviated by the RNF115 inhibitor disulfiram (DSF). Knockout of RNF115 or treatment with DSF significantly inhibit systemic inflammation and autoimmune lethality and restore immune cell development in Trex1-/- mice and STINGN153S/WT bone marrow chimeric mice. In addition, knockdown or pharmacological inhibition of RNF115 substantially downregulate the expression of IFN-α, IFN-γ and proinflammatory cytokines in PBMCs from patients with systemic lupus erythematosus (SLE) who exhibit high concentrations of dsDNA in peripheral blood. Mechanistically, knockout or inhibition of RNF115 impair the oligomerization and Golgi localization of STING in various types of cells transfected with cGAMP and in organs and cells from Trex1-/- mice. Interestingly, knockout of RNF115 inhibits the activation and Golgi localization of STINGN153S as well as the expression of proinflammatory cytokines in myeloid cells but not in endothelial cells or fibroblasts. Taken together, these findings highlight the RNF115-mediated cell type-specific regulation of STING and STINGN153S and provide potential targeted intervention strategies for STING-related autoimmune diseases.

Ubiquitination Process Mediates Prostate Cancer Development and Metastasis through Multiple Mechanisms

Prostate cancer (PCa) is a common malignant tumor in men, when the disease progresses to the advanced stage, most patients will develop distant metastasis and develop into castration-resistant prostate cancer (CRPC), resulting in increased mortality. Ubiquitination is a widespread protein post-translational modification process in the biological world, and it plays an important role in the development and transfer of PCa. E3 ubiquitin ligase plays an important role in the specific selection and role of substrates in the process of ubiquitination ligase. This review will briefly introduce the ubiquitination process and E3 ubiquitin ligase, focus on the recently discovered multiple mechanisms by which ubiquitination affects PCa development and metastasis, and a summary of the current emerging proteolysis-targeting chimeras (PROTAC) in the treatment of PCa.

RNF115/BCA2 deficiency alleviated acute liver injury in mice by promoting autophagy and inhibiting inflammatory response

The E3 ubiquitin ligase RING finger protein 115 (RNF115), also known as breast cancer-associated gene 2 (BCA2), has been linked with the growth of some cancers and immune regulation, which is negatively correlated with prognosis. Here, it is demonstrated that the RNF115 deletion can protect mice from acute liver injury (ALI) induced by the treatment of lipopolysaccharide (LPS)/D-galactosamine (D-GalN), as evidenced by decreased levels of alanine aminotransaminase, aspartate transaminase, inflammatory cytokines (e.g., tumor necrosis factor α and interleukin-6), chemokines (e.g., MCP1/CCL2) and inflammatory cell (e.g., monocytes and neutrophils) infiltration. Moreover, it was found that the autophagy activity in Rnf115-/- livers was increased, which resulted in the removal of damaged mitochondria and hepatocyte apoptosis. However, the administration of adeno-associated virus Rnf115 or autophagy inhibitor 3-MA impaired autophagy and aggravated liver injury in Rnf115-/- mice with ALI. Further experiments proved that RNF115 interacts with LC3B, downregulates LC3B protein levels and cell autophagy. Additionally, Rnf115 deletion inhibited M1 type macrophage activation via NF-κB and Jnk signaling pathways. Elimination of macrophages narrowed the difference in liver damage between Rnf115+/+ and Rnf115-/- mice, indicating that macrophages were linked in the ALI induced by LPS/D-GalN. Collectively, for the first time, we have proved that Rnf115 inactivation ameliorated LPS/D-GalN-induced ALI in mice by promoting autophagy and attenuating inflammatory responses. This study provides new evidence for the involvement of autophagy mechanisms in the protection against acute liver injury.

Clinical implications of RAB13 expression in pan-cancer based on multi-databases integrative analysis

Worldwide, cancer is a huge burden, and each year sees an increase in its incidence. RAB (Ras-related in brain) 13 is crucial for a number of tumor types. But more research on RAB13's tumor-related mechanism is still required. This study's goal was to investigate RAB13's function in human pan-cancer, and we have also preliminarily explored the relevant mechanisms. To investigate the differential expression, survival prognosis, immunological checkpoints, and pathological stage of RAB13 in human pan-cancer, respectively, databases of TIMER2.0, GEPIA 2, and UALCAN were employed. CBioPortal database was used to analyze the mutation level, meanwhile, PPI network was constructed based on STRING website. The putative functions of RAB13 in immunological infiltration were investigated using single sample gene set enrichment analysis (ssGSEA). The mechanism of RAB13 in hepatocellular cancer was also briefly investigated by us using gene set enrichment analysis (GSEA). RAB13 was differentially expressed in a number of different cancers, including liver hepatocellular carcinoma (LIHC), stomach adenocarcinoma (STAD), etc. Additionally, RAB13 overexpression in LGG and LIHC is associated with a worse prognosis, including overall survival (OS) and disease-free survival (DFS). Then, we observed that early in BLCA, BRAC, CHOL, ESCA, HNSC, KICH, KIRC, LIHC, LUAD, LUSC, and STAD, the level of RAB13 expression was raised. Next, we found that "amplification" was the most common mutation in RAB13. The expression of SLC39A1, JTB, SSR2, SNAPIN, and RHOC was strongly positively linked with RAB13, according to a correlation study. RAB13 favorably regulated B cell, CD8 + T cell, CD4 + T cell, macrophage, neutrophil, and dendritic cell in LIHC, according to immune infiltration analysis. Immune checkpoint study revealed a positive correlation between RAB13 expression and PD1, PDL1, and CTLA4 in LIHC. According to GSEA, RAB13 is involved in a number of processes in LIHC, including MTORC1 signaling, MYC targets v1, G2M checkpoint, MITOTIC spindle, DNA repair, P53 pathway, glycolysis, PI3K-AKT-MTOR signaling, etc. RAB13 is a possible therapeutic target in LIHC and can be used as a prognostic marker.

Myoglobin in Brown Adipose Tissue: A Multifaceted Player in Thermogenesis

Brown adipose tissue (BAT) plays an important role in energy homeostasis by generating heat from chemical energy via uncoupled oxidative phosphorylation. Besides its high mitochondrial content and its exclusive expression of the uncoupling protein 1, another key feature of BAT is the high expression of myoglobin (MB), a heme-containing protein that typically binds oxygen, thereby facilitating the diffusion of the gas from cell membranes to mitochondria of muscle cells. In addition, MB also modulates nitric oxide (NO•) pools and can bind C16 and C18 fatty acids, which indicates a role in lipid metabolism. Recent studies in humans and mice implicated MB present in BAT in the regulation of lipid droplet morphology and fatty acid shuttling and composition, as well as mitochondrial oxidative metabolism. These functions suggest that MB plays an essential role in BAT energy metabolism and thermogenesis. In this review, we will discuss in detail the possible physiological roles played by MB in BAT thermogenesis along with the potential underlying molecular mechanisms and focus on the question of how BAT-MB expression is regulated and, in turn, how this globin regulates mitochondrial, lipid, and NO• metabolism. Finally, we present potential MB-mediated approaches to augment energy metabolism, which ultimately could help tackle different metabolic disorders.

Protein quality control machinery supports primary ciliogenesis by eliminating GDP-bound Rab8-family GTPases

The small GTPase Rab8 plays a vital role in the vesicular trafficking of cargo proteins from the trans-Golgi network to target membranes. Upon reaching its target destination, Rab8 is released from the vesicular membrane into the cytoplasm via guanosine triphosphate (GTP) hydrolysis. The fate of GDP-bound Rab8 released from the destination membranes, however, has not been investigated adequately. In this study, we found that GDP-bound Rab8 subfamily proteins are targeted for immediate degradation, and the pre-emptive quality control machinery is responsible for eliminating these proteins in a nucleotide-specific manner. We provide evidence that components of this quality control machinery have a critical role in vesicular trafficking events, including the formation of primary cilia, a process regulated by the Rab8 subfamily. These results suggest that the protein degradation machinery plays a critical role in the integrity of membrane trafficking by limiting the excessive accumulation of GDP-bound Rab8 subfamily proteins.

Construction of Two Independent RAB Family-Based Scoring Systems Based on Machine Learning Algorithms and Definition of RAB13 as a Novel Therapeutic Target for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) remains a global health challenge with a low early diagnosis rate and high mortality. The Rab GTPase (RAB) family plays an essential role in the occurrence and progression of HCC. Nonetheless, a comprehensive and systematic investigation of the RAB family has yet to be performed in HCC. We comprehensively assessed the expression landscape and prognostic significance of the RAB family in HCC and systematically correlated these RAB family genes with tumor microenvironment (TME) characteristics. Then, three RAB subtypes with distinct TME characteristics were determined. Using a machine learning algorithm, we further established a RAB score to quantify TME features and immune responses of individual tumors. Moreover, to better evaluate patient prognosis, we established a RAB risk score as an independent prognostic factor for patients with HCC. The risk models were validated in independent HCC cohorts and distinct HCC subgroups, and their complementary advantages guided clinical practice. Furthermore, we further confirmed that the knockdown of RAB13, a pivotal gene in risk models, suppressed HCC cell proliferation and metastasis by inhibiting the PI3K/AKT signaling pathway, CDK1/CDK4 expression, and epithelial-mesenchymal transition. In addition, RAB13 inhibited the activation of JAK2/STAT3 signaling and the expression of IRF1/IRF4. More importantly, we confirmed that RAB13 knockdown enhanced GPX4-dependent ferroptosis vulnerability, highlighting RAB13 as a potential therapeutic target. Overall, this work revealed that the RAB family played an integral role in forming HCC heterogeneity and complexity. RAB family-based integrative analysis contributed to enhancing our understanding of the TME and guided more effective immunotherapy and prognostic evaluation.

SGOL2 promotes prostate cancer progression by inhibiting RAB1A ubiquitination

Prostate cancer is the most prevalent genitourinary malignant cancer in men worldwide. Patients with prostate cancer who progress to castration-resistant prostate cancer (CRPC) or metastatic CRPC have significantly poorer survival. Advanced prostate cancer is a clinical challenge due to the lack of effective treatment strategies. In the field of oncology, SGOL2 was an emerging and differentially expressed molecule, which enhanced the proliferation of cell populations in vitro in our studies. Mass spectrum and Co-IP validated the interaction of SGOL2 and RAB1A in a protein-protein manner. We further investigated the role of SGOL2 in the regulatory mechanism of RAB1A in prostate cancer cell lines. Furthermore, SGOL2 regulated RAB1A expression by inhibiting its ubiquitination. Rescue Experiments demonstrated that SGOL2 promoted prostate cancer cell proliferation and migration by upregulating RAB1A expression. Finally, we found that SGOL2 and RAB1A may regulate the tumor microenvironment (TME) in prostate cancer. In conclusion, our findings concluded that SGOL2 stabilized RAB1A expression to promote prostate cancer development. Both of them were of great importance in TME modulation.

The Transient Receptor Potential Vanilloid 2 (TRPV2) Channel Facilitates Virus Infection Through the Ca2+ -LRMDA Axis in Myeloid Cells

The transient receptor potential vanilloid 2 (TRPV2) channel is a nonselective cation channel that has been implicated in multiple sensory processes in the nervous system. Here, it is shown that TRPV2 in myeloid cells facilitates virus penetration by promoting the tension and mobility of cell membrane through the Ca²⁺ -LRMDA axis. Knockout of TRPV2 in myeloid cells or inhibition of TRPV2 channel activity suppresses viral infection and protects mice from herpes simplex virus 1 (HSV-1) and vesicular stomatitis virus (VSV) infection. Reconstitution of TRPV2 but not the Ca²⁺ -impermeable mutant TRPV2^E572Q into LyZ2-Cre;Trpv2^fl/fl bone marrow-derived dendritic cells (BMDCs) restores viral infection. Mechanistically, knockout of TRPV2 in myeloid cells inhibits the tension and mobility of cell membrane and the penetration of viruses, which is restored by reconstitution of TRPV2 but not TRPV2^E572Q . In addition, knockout of TRPV2 leads to downregulation of Lrmda in BMDCs and BMDMs, and knockdown of Lrmda significantly downregulates the mobility and tension of cell membrane and inhibits viral infections in Trpv2^fl/fl but not LyZ2-Cre;Trpv2^fl/fl BMDCs. Consistently, complement of LRMDA into LyZ2-Cre;Trpv2^fl/fl BMDCs partially restores the tension and mobility of cell membrane and promotes viral penetration and infection. These findings characterize a previously unknown function of myeloid TRPV2 in facilitating viral infection though the Ca2⁺ -LRMDA axis.

The E3 ubiquitin ligase ARIH1 promotes antiviral immunity and autoimmunity by inducing mono-ISGylation and oligomerization of cGAS

The cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS) plays a critical role in antiviral immunity and autoimmunity. The activity and stability of cGAS are fine-tuned by post-translational modifications. Here, we show that ariadne RBR E3 ubiquitin protein ligase 1 (ARIH1) catalyzes the mono-ISGylation and induces the oligomerization of cGAS, thereby promoting antiviral immunity and autoimmunity. Knockdown or knockout of ARIH1 significantly inhibits herpes simplex virus 1 (HSV-1)- or cytoplasmic DNA-induced expression of type I interferons (IFNs) and proinflammatory cytokines. Consistently, tamoxifen-treated ER-Cre;Arih1fl/fl mice and Lyz2-Cre; Arih1fl/fl mice are hypersensitive to HSV-1 infection compared with the controls. In addition, deletion of ARIH1 in myeloid cells alleviates the autoimmune phenotypes and completely rescues the autoimmune lethality caused by TREX1 deficiency. Mechanistically, HSV-1- or cytosolic DNA-induced oligomerization and activation of cGAS are potentiated by ISGylation at its K187 residue, which is catalyzed by ARIH1. Our findings thus reveal an important role of ARIH1 in innate antiviral and autoimmune responses and provide insight into the post-translational regulation of cGAS.

Multifaceted Roles of the E3 Ubiquitin Ligase RING Finger Protein 115 in Immunity and Diseases

Ubiquitination is a post-translational modification that plays essential roles in various physiological and pathological processes. Protein ubiquitination depends on E3 ubiquitin ligases that catalyze the conjugation of ubiquitin molecules on lysine residues of targeted substrates. RING finger protein 115 (RNF115), also known as breast cancer associated gene 2 (BCA2) and Rab7-interacting RING finger protein (Rabring7), has been identified as a highly expressed protein in breast cancer cells and tissues. Later, it has been demonstrated that RNF115 catalyzes ubiquitination of a series of proteins to modulate a number of signaling pathways, and thereby regulates viral infections, autoimmunity, cell proliferation and death and tumorigenesis. In this review, we introduce the identification, expression and activity regulation of RNF115, summarize the substrates and functions of RNF115 in different pathways, and discuss the roles of RNF115 as a biomarker or therapeutic target in diseases.