Ubiquitin Ligases CBL and CBL-B Maintain the Homeostasis and Immune Quiescence of Dendritic Cells

c-CBL/LCK/c-JUN/ETS1/CD28 axis restrains childhood asthma by suppressing Th2 differentiation

BACKGROUND

Asthma is a common immune disease with high morbidity in children. Type 2 inflammation is the center of asthma development, and mainly mediated by a subset of CD4 + T cells, T helper 2 (Th2) cells. Excess Th2 differentiation was generally associated with asthmatic attack. Casitas B-lineage lymphoma (c-CBL) was reported to involved in T cell development and databank showed its decreased expression in CD4 + T cells from peripheral blood of asthmatic children. This study aims to investigate the role of c-CBL in childhood asthma and Th2 differentiation, and explore the underlying mechanism.

METHODS

We collected peripheral blood samples from clinical childhood asthma cases and healthy controls, and determined c-CBL expression in CD4 + T cells. Asthma was induced in neonatal mice by ovalbumin (OVA) intraperitoneal injection and aerosol inhalation, and c-CBL expression in CD4 + T cells from peripheral blood and spleen was measured. Gain-of-function experiments was performed to confirm the effects of c-CBL on Th2 differentiation in vitro. Finally, c-CBL was delivered into asthmatic mice via lentivirus infection to verify its effects on experimental asthma.

RESULTS

c-CBL was lowly expressed in CD4 + T cells from asthmatic children than those of healthy controls. Similarly, it was downregulated in CD4 + T cells from peripheral blood and spleen of asthma mice. Overexpression of c-CBL restrained lung pathological injury and type 2 inflammation in experimental asthmatic mice. Gain-of-function experiments demonstrated that c-CBL inhibited Th2 differentiation of CD4 + T cells from healthy children, and mediated the ubiquitination of lymphocyte cell-specific protein-tyrosine kinase (LCK). LCK acted as a kinase to phosphorylate and activate c-JUN, which was predicted to bind promoter sequence of CD28 by bioinformatic analysis. Dual-luciferase reporter assay verified that c-JUN and ETS1 synergically enhanced transcription of CD28, and this transcription activation was aggravated by LCK overexpression.

CONCLUSION

c-CBL alleviated asthma and suppressed Th2 differentiation by facilitating LCK ubiquitination, interrupting c-JUN activation and CD28 expression in vivo and in vitro. c-CBL/LCK/c-JUN/ETS1/CD28 axis was partially involved in childhood asthma, and may provide novel insights for clinical treatment for asthma.

The immunobiology of myelodysplastic neoplasms: a mini-review

This mini review summarizes the immunobiology of myelodysplastic syndromes, specifically focusing on the interactions between immune cells, cytokines, and dysplastic cells within the tumor microenvironment in the bone marrow. We elucidate in detail how immune dysregulation and evasion influence the initiation and progression of myelodysplastic syndromes, as well as resistance to therapy and progression to AML. In addition, we highlight a range of therapeutic strategies, including the most recent breakthroughs and experimental therapies for treating MDS. Finally, we address the existing knowledge gaps in the understanding of the immunobiology of MDS and propose future research directions, promising advancements toward enhancing clinical outcomes and survival for patients with MDS.

Crosstalk of ubiquitin system and non-coding RNA in fibrosis

Chronic tissue injury triggers changes in the cell type and microenvironment at the site of injury and eventually fibrosis develops. Current research suggests that fibrosis is a highly dynamic and reversible process, which means that human intervention after fibrosis has occurred has the potential to slow down or cure fibrosis. The ubiquitin system regulates the biological functions of specific proteins involved in the development of fibrosis, and researchers have designed small molecule drugs to treat fibrotic diseases on this basis, but their therapeutic effects are still limited. With the development of molecular biology technology, researchers have found that non-coding RNA (ncRNA) can interact with the ubiquitin system to jointly regulate the development of fibrosis. More in-depth explorations of the interaction between ncRNA and ubiquitin system will provide new ideas for the clinical treatment of fibrotic diseases.

Association between CBL gene polymorphism and susceptibility of microscopic polyangiitis in a Chinese population: A case-control analysis

OBJECTIVE

To assess whether Casitas B-lineage lymphoma (CBL) gene polymorphism influences the risk of microscopic polyangiitis (MPA) in Chinese populations.

METHODS

In total, 266 MPA patients and 297 healthy controls were recruited for a case-control study. Five CBL SNPs were genotyped using multiplex polymerase chain reaction and high-throughput sequencing. The relationship between SNPs and the risk of MPA under different genetic models was evaluated by SNPstats. SNP-SNP interaction was analyzed by generalized multifactor dimensionality reduction (GMDR). Finally, the association between CBL SNPs and treatment effects were assessed.

RESULTS

The results showed that CBL rs2276083 was associated with decreasing MPA risk under dominant (OR: 0.53; p = 0.014) and recessive models (OR: 0.52; p = 0.0034). Stratification analysis indicated that rs2276083 and rs2509671 in age < 60 years, rs2276083 in female or in Han population were protective factors for MPA. The CBL haplotype (A-A-G-C-T) was associated with an increased risk of MPA. GMDR suggested that CBL rs2276083, phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha (PI3KCA) rs1607237, and autophagy-related gene 7 (ATG7) rs7549008 might interact with each other in MPA development (p = 0.0107). CBL rs1047417 with AG genotype and rs11217234 with AG genotype had better clinical treatment effects than other two genotypes (p = 0.048 and p = 0.025, respectively).

CONCLUSION

The genetic polymorphism of CBL had a potential association with the risk of MPA and clinical treatment effects in Guangxi population in China.

E3 ubiquitin ligase CBLB regulates innate immune responses and bacterial dissemination during nontuberculous mycobacteria infection

Nontuberculous mycobacteria (NTM) are emerging opportunistic pathogens causing pulmonary infection to fatal disseminated disease. NTM infections are steadily increasing in children and adults, and immune-compromised individuals are at a greater risk of fatal infections. The NTM disease's adverse pathology and resistance to antibiotics have further worsened the therapeutic measures. Innate immune regulators are potential targets for therapeutics to NTM, especially in a T cell-suppressed population, and many ubiquitin ligases modulate pathogenesis and innate immunity during infections, including mycobacterial infections. Here, we investigated the role of an E3 ubiquitin ligase, Casitas B-lineage lymphoma proto-oncogene B (CBLB), in immunocompromised mouse models of NTM infection. We found that CBLB is essential to prevent bacterial growth and dissemination. Cblb deficiency debilitated natural killer cells, inflammatory monocytes, and macrophages in vivo. However, Cblb deficiency in macrophages did not wane its ability to inhibit bacterial growth or production of reactive oxygen species or interferon γ production by natural killer cells in vitro. CBLB restricted NTM growth and dissemination by promoting early granuloma formation in vivo. Our study shows that CBLB bolsters innate immune responses and helps prevent the dissemination of NTM during compromised T cell immunity.

Integrated Bioinformatics Analysis for Revealing CBL is a Potential Diagnosing Biomarker and Related Immune Infiltration in Parkinson's Disease

Purpose

There is growing evidence that the immune system plays an important role in the progression of Parkinson's disease, the second most common neurodegenerative disorder. This study aims to address the comprehensive understanding of the immunopathogenesis of Parkinson's disease and explore new inflammatory biomarkers.

Patients and Methods

In this study, Immune-related differential expressed genes (DEIRGs) were obtained from GEO database and Immport database. The hub gene was screened in DEIRGs using LASSO regression and random forest algorithm, and the mRNA expression of the identified hub gene was validated using clinical blood samples.

Results

We obtained a total of 157 DEIRGs that played an important role in the immune response. The results of immune cell infiltration analysis showed that the degree of memory B cells infiltration was higher in PD patients, while the degree of Monocytes, resting mast cells and M0 macrophages infiltration was lower (p<0.05). A total of 8 hub genes were screened by machine learning methods, and RT-PCR results showed that the expression level of CBL gene in PD was significantly increased (p<0.05).

Conclusion

Our findings suggest that CBL is a new potential diagnostic biomarker for PD and that abnormal immune cell infiltration may influence PD development.

Identification of immunological characteristics and cuproptosis-related molecular clusters in primary Sjögren's syndrome

BACKGROUND

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune disease characterized by lymphocyte infiltration of the exocrine glands. The typical clinical symptoms of pSS include dryness of the mouth (xerostomia) and eyes (xerophthalmia), fatigue, and joint pain. Cuproptosis is a recently identified mode of programmed cell death that leads to the progression of multiple diseases, and the precise etiology and pathophysiology of pSS remain unknown. Consequently, the aim of our study was to explore cuproptosis-related molecular clusters and identify key genes in pSS.

METHOD

Gene expression profiles of the peripheral blood in the GSE84844 dataset were downloaded to identify the expression characteristics of cuproptosis regulators and immune cell infiltration. Subsequently, further exploration was conducted on the clusters involving cuproptosis-related genes (CRGs) and the corresponding immune cell infiltration, and the WGCNA algorithm was applied to explore the cluster-specific differentially expressed genes. Finally, the best machine prediction model was selected for candidate hub cuproptosis-associated genes and the accuracy of predictive efficiency was verified by the salivary gland in an external dataset (GSE143153) and enzyme-linked immunosorbent assay.

RESULT

Through a comparison of patients with pSS and controls, 7 CRGs and 4 types of immune cells were identified. Immune cell infiltration revealed significant immune heterogeneity in three cuproptosis-related molecular clusters in pSS. The random forest machine model showed the best discriminatory performance (area under the receiver operating characteristic curve (AUC) = 1.000) and built a predictive model based on 5 genes, which demonstrated satisfactory performance (AUC = 0.70) in the GSE143153 dataset. Based on serum samples, EED (AUC = 0.557), CBL (AUC = 0.635), and NFU1 (AUC = 0.655) showed lower expression levels in patients with pSS (p = 0.037, p = 0.000, p = 0.000, respectively).

CONCLUSION

In this study, we systematically analyzed the association between pSS and cuproptosis, established a predictive model that screened for high-risk genes linked to the advancement of pSS, and explored the pathogenic mechanisms and novel therapeutic strategies for pSS, targeting EED, CBL and NFU1.

SYK ubiquitination by CBL E3 ligases restrains cross-presentation of dead cell-associated antigens by type 1 dendritic cells

Cross-presentation of dead cell-associated antigens by conventional dendritic cells type 1 (cDC1s) is critical for CD8+ T cells response against many tumors and viral infections. It is facilitated by DNGR-1 (CLEC9A), an SYK-coupled cDC1 receptor that detects dead cell debris. Here, we report that DNGR-1 engagement leads to rapid activation of CBL and CBL-B E3 ligases to cause K63-linked ubiquitination of SYK and terminate signaling. Genetic deletion of CBL E3 ligases or charge-conserved mutation of target lysines within SYK abolishes SYK ubiquitination and results in enhanced DNGR-1-dependent antigen cross-presentation. We also find that cDC1 deficient in CBL E3 ligases are more efficient at cross-priming CD8+ T cells to dead cell-associated antigens and promoting host resistance to tumors. Our findings reveal a role for CBL-dependent ubiquitination in limiting cross-presentation of dead cell-associated antigens and highlight an axis of negative regulation of cDC1 activity that could be exploited to increase anti-tumor immunity.

Ablation of Cbl-b and c-Cbl in dendritic cells causes spontaneous liver cirrhosis via altering multiple properties of CD103+ cDC1s

The Casitas B-lineage lymphoma (Cbl) family proteins are E3 ubiquitin ligases implicated in the regulation of various immune cells. However, their function in dendritic cells (DCs) remains unclear. To investigate the role of Cbl family members in DCs, we created dendritic cell double-deficient Casitas B lymphoma-b (Cbl-b) and Casitas B lineage lymphoma (c-Cbl) mice by crossing Cbl-b^−/− mice with c-Cbl^flox/flox CD11c-Cre⁺ mice. We found that specific deletion of Cbl-b and c-Cbl in CD11c⁺ cells, predominantly in DCs, led to liver fibrosis, cirrhosis, and accumulation of systemic conventional Type I DCs (cDC1s) due to enhanced cell proliferation and decreased cell apoptosis. In addition to a change in DC number, double knockout (dKO) cDC1s exhibited a partially activated status as indicated by high basal expression levels of certain cytokines and possessed an enhanced capacity to prime T cells. After adoptive transfer, dKO cDC1s could drive liver fibrosis too. In further experiments, we demonstrated that Cbl-b and c-Cbl could target signal transducer and activator of transcription 5 (STAT5), a transcriptional repressor for the pro-apoptotic protein Bim, to promote ubiquitination-mediated degradation and cell apoptosis in cDC1s. Further extensive experiments revealed that Cbl-b mediated K27-linked ubiquitination of lysine 164 of STAT5a while c-Cbl induced K29-linked ubiquitination of lysine 696 of STAT5a and K27-linked ubiquitination of lysine 140 and 694 of STAT5b. Thus, our findings indicate a functional redundancy of Cbl-b and c-Cbl in cDC homeostasis and maturation.

Mechanism of Yangxinshi Intervention on Cardiac Fibrosis in Diabetic Cardiomyopathy Based on Network Pharmacology

Background

Cardiac fibrosis (CF) is major myocardial change in diabetic cardiomyopathy (DCM). Yangxinshi as a Chinese medicine formula is used to treat cardiovascular diseases. However, the exact effective mechanism of Yangxinshi on CF is still uncertain. Hence, based on the pharmacological network, predicting the active components, potential targets and pathways of Yangxinshi on diabetic fibrosis require to be further studied.

Materials and Methods

By using Cytoscape 3.6.0 Bisogenet plug-in, the active components of Yangxinshi were obtained and screened through TCMSP, and the PPI network of DCM-CF was constructed and then screened by CytoNCA plug-in. GO analysis and KEGG pathway enrichment analysis were carried out by Cluego plug-in. Combined with the results of network pharmacological analysis, cells in vitro were performed to verify the CF stimulated with high glucose or intervence with Yangxinshi, and the expressions of Cbl-b, p-smad2, and α-SMA were detected.

Results

Yangxinshi might play a key role in reversing cardiac fibrosis in individuals with DCM by regulating the signal pathway of CBL and promoted the expression of Cbl-b and inhibited the expression of p-smad2 and α-SMA, verifying some predictive work via network pharmacology.

Conclusion

Based on network pharmacology, this study demonstrates that the beneficial effect of Yangxinshi on CF is related to the Cbl-b/smad2 pathway, providing an idea for the therapeutic effect of Yangxinshi on cardiac fibrosis in DCM.