Regulatory T cells demonstrate significantly increased functions following stimulation with IL-2 in a Tim-3-dependent manner in intracranial aneurysms

A mendelian randomization study investigates the causal relationship between immune cell phenotypes and cerebral aneurysm

Background: Cerebral aneurysms (CAs) are a significant cerebrovascular ailment with a multifaceted etiology influenced by various factors including heredity and environment. This study aimed to explore the possible link between different types of immune cells and the occurrence of CAs. Methods: We analyzed the connection between 731 immune cell signatures and the risk of CAs by using publicly available genetic data. The analysis included four immune features, specifically median brightness levels (MBL), proportionate cell (PC), definite cell (DC), and morphological attributes (MA). Mendelian randomization (MR) analysis was conducted using the instrumental variables (IVs) derived from the genetic variation linked to CAs. Results: After multiple test adjustment based on the FDR method, the inverse variance weighted (IVW) method revealed that 3 immune cell phenotypes were linked to the risk of CAs. These included CD45 on HLA DR+NK (odds ratio (OR), 1.116; 95% confidence interval (CI), 1.001-1.244; p = 0.0489), CX3CR1 on CD14- CD16- (OR, 0.973; 95% CI, 0.948-0.999; p = 0.0447). An immune cell phenotype CD16- CD56 on NK was found to have a significant association with the risk of CAs in reverse MR study (OR, 0.950; 95% CI, 0.911-0.990; p = 0.0156). Conclusion: Our investigation has yielded findings that support a substantial genetic link between immune cells and CAs, thereby suggesting possible implications for future clinical interventions.

Identification of immune-related molecular markers in intracranial aneurysm (IA) based on machine learning and cytoscape-cytohubba plug-in

BACKGROUND

Intracranial aneurysm (IA) is a common cerebrovascular disease. The immune mechanism of IA is more complicated, and it is unclear so far. Therefore, it is necessary to continue to explore the immune related molecular mechanism of IA.

METHODS

All data were downloaded from the public database. Limma package and ssGSEA algorithm was used to identify differentially expressed mRNAs (DEmRNAs) and analyze immune cell infiltration, respectively. Machine learning and cytoscape-cytohubba plug-in was used to identify key immune types and multicentric DEmRNAs of IA, respectively. Multicentric DEmRNAs related to key immune cells were screened out as key DEmRNAs by Spearman correlation analysis. Diagnostic models, competing endogenous RNA (ceRNA) regulatory network and transcription factor regulatory network were constructed based on key DEmRNAs. Meanwhile, drugs related to key DEmRNAs were screened out based on DGIdb database. The expression of key DEmRNAs was also verified by real time-PCR.

RESULTS

In this study, 7 key DEmRNAs (NRXN1, GRIA2, SLC1A2, SLC17A7, IL6, VEGFA and SYP) associated with key differential immune cell infiltration (CD56bright natural killer cell, Immature B cell and Type 1 T helper cell) were identified. Functional enrichment analysis showed that VEGFA and IL6 may be involved in the regulation of the PI3K-Akt signaling pathway. Moreover, IL6 was also found to be enriched in cytokine-cytokine receptor interaction signaling pathway. In the ceRNA regulatory network, a large number of miRNAs and lncRNAs were found. In the transcription factor regulatory network, the transcription factor SP1 was correlated with VEGFA, SYP and IL6. It is also predicted that drugs related to key DEmRNAs such as CARBOPLATIN, FENTANYL and CILOSTAZOL may contribute to the treatment of IA. In addition, it was also found that SVM and RF models based on key DEmRNAs may be potential markers for diagnosing IA and unruptured intracranial aneurysm (UIA), respectively. The expression trend of key DEmRNAs verified by real-time PCR was consistent with the bioinformatics analysis results.

CONCLUSION

The identification of molecules and pathways in this study provides a theoretical basis for understanding the immune related molecular mechanism of IA. Meanwhile, the drug prediction and diagnosis model construction may also be helpful for clinical diagnosis and management.

Pro-Inflammatory and Anti-Inflammatory Cytokines Levels are Significantly Altered in Cerebrospinal Fluid of Unruptured Intracranial Aneurysm (UIA) Patients

Introduction

Identifying all the relevant “players” in the formation and development of brain aneurysms may help understand the mechanisms responsible for the formation of an aneurysm, as well as in the search for non-invasive targets for aneurysm pharmacotherapy.

Aim

The evaluation of the concentration of pro-inflammatory and anti-inflammatory cytokines in cerebrospinal fluid (CSF) and serum of patients with unruptured intracranial aneurysms (UIA) in comparison to individuals without vascular lesions in the brain.

Methods

The concentration of 27 proteins in the CSF and serum of UIA patients (N = 40) and individuals without vascular lesions in the brain (N = 15) was evaluated using a multiplex ELISA kit (Bio-Plex Pro Human Cytokine 27-Plex Panel).

Results

In the CSF 13 out of 27 proteins evaluated presented a concentration 1.36-fold or greater in UIA patients in comparison to the control group. Significantly higher were IL-1β, IL-1ra, IL-2, IL-4, IL-5, IL-7, IL-8, IL-12, IL-13, TNF-α, INF-γ, MCP-1, and VEGF. In the serum none of the proteins evaluated significantly differ between UIA patients and the control group. The correlation coefficient analysis showed that CSF IL-1β, IL-8, and TNF-α positively, while IL-13 negatively correlated with the size of aneurysms. CSF IL-6 and MCP-1 concentrations positively correlated with the number of aneurysms.

Conclusion

In patients with UIA, pro-inflammatory and anti-inflammatory mechanisms are activated simultaneously, because the concentration of promoting and suppressing inflammatory response proteins was significantly higher in CSF of UIA patients compared to the control group. The preventive therapy of brain aneurysm development should be focused on IL-1β, IL-6, IL-8, MCP-1, and TNF-α, the concentration of which in CSF positively correlated with the size and number of aneurysms.

The role of A Disintegrin and Metalloproteinase (ADAM)-10 in T helper cell biology

A Disintegrin and Metalloproteinases (ADAM)-10 is a member of a family of membrane-anchored proteinases that regulate a broad range of cellular functions with central roles within the immune system. This has spurred the interest to modulate ADAM activity therapeutically in immunological diseases. CD4 T helper (Th) cells are the key regulators of adaptive immune responses. Their development and function is strongly dependent on Notch, a key ADAM-10 substrate. However, Th cells rely on a variety of additional ADAM-10 substrates regulating their functional activity at multiple levels. The complexity of both, the ADAM substrate expression as well as the functional consequences of ADAM-mediated cleavage of the various substrates complicates the analysis of cell type specific effects. Here we provide an overview on the major ADAM-10 substrates relevant for CD4 T cell biology and discuss the potential effects of ADAM-mediated cleavage exemplified for a selection of important substrates.

A Two-Gene-Based Diagnostic Signature for Ruptured Intracranial Aneurysms

Background: Ruptured intracranial aneurysm (IA) is a disease with high mortality. Despite the great progress in treating ruptured IA, methods for risk assessment of ruptured IA remain limited. Methods: In this study, we aim to develop a robust diagnostic model for ruptured IA. Gene expression profiles in blood samples of 18 healthy persons and 43 ruptured IA patients were obtained from the Gene Expression Omnibus (GEO). Differential expression analysis was performed using limma Bioconductor package followed by functional enrichment analysis via clusterProfiler Bioconductor package. Immune cell compositions in ruptured IA and healthy samples were assessed through the CIBERSORT tool. Protein-protein interaction (PPI) was predicted based on the STRING database. Logistic regression model was used for the construction of predictive model for distinguishing ruptured IA and healthy samples. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to validate the gene expression between the ruptured IA and healthy samples. Results: A total of 58 differentially expressed genes (DEGs) were obtained for ruptured IA patients compared with healthy controls. Functional enrichment analysis showed that the DEGs were enriched in biological processes related to neutrophil activation, neutrophil degranulation, and cytokine-cytokine receptor interaction. Notably, immune analysis results proved that the rupture of IA might be related to immune cell distribution. We further identified 24 key genes as hub genes using the PPI networks. The logistic regression model trained based on the 24 key genes ultimately retained two genes, i.e., IL2RB and CCR7, which had great potential for risk assessment for rupture of IA. The RT-qPCR further validated that compared with the healthy samples, the expression levels of IL2RB and CCR7 were decreased in ruptured IA samples. Conclusions: This study might be helpful for cohorts who have a high risk of ruptured IA for early diagnosis and prevention of the disease.

Targeting STAT3 Abrogates Tim-3 Upregulation of Adaptive Resistance to PD-1 Blockade on Regulatory T Cells of Melanoma

Background

Less than 20% of melanoma patients respond to programmed cell death-1 (PD-1) blockade immunotherapies. Thus, it is crucial to understand the dynamic changes in the tumor microenvironment (TME) after PD-1 blockade, for developing immunotherapy efficacy.

Methods

A genomic analysis was conducted by The Cancer Genome Atlas (TCGA) datasets and web platform TIMER2.0 datasets. Pathway enrichment analysis was performed using the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. Peripheral blood mononuclear cells (PBMCs), regulatory T (Treg) cells, and B16-F10 melanoma mice were used as models. The cellular and molecular characteristics and mechanisms of Treg cells in melanoma were assessed by performing gene expression studies, immunohistochemistry, RNA sequencing, and flow cytometry.

Results

Here, we evaluate the countenance of T cell immunoglobulin and mucin-domain containing-3 (Tim-3), and various immunosuppressive factors within tumor-infiltrated Treg cells after treatment with anti-PD-1 or the indicator transduction and activator of transcription 3 (STAT3) inhibitors. Increased expression of Tim-3 is markedly observed within the tissues of the PD-1 blockade resistance of melanoma patients. Targeting STAT3 significantly boosts the response of resistant-PD-1 therapy within the melanoma mouse model. Mechanistically, the manifestation of STAT3 decreases the expression of Tim-3 and various cytokines in the purified Treg cells from individual PBMCs and the murine melanoma model, limiting the immunosuppression of Treg cells.

Conclusions

Our findings indicate that Tim-3 expression on Treg cells within the TME is STAT3-dependent, providing support to STAT3 as a target and enhancing the immunotherapy for patients suffering from melanoma.

The potential for immune checkpoint modulators in cerebrovascular injury and inflammation

Introduction: Neuroinflammation has been linked to poor neurologic and functional outcomes in many cerebrovascular disorders. Immune checkpoints are upregulated in the setting of traumatic brain injury, intracerebral hemorrhage, ischemic stroke, central nervous systems vasculitis, and post-hemorrhagic vasospasm, and are potential mediators of pathologic inflammation. Burgeoning evidence suggests that immune checkpoint modulation is a promising treatment strategy to decrease immune cell recruitment, cytokine secretion, brain edema, and neurodegeneration.Areas covered: This review discusses the role of immune checkpoints in neuroinflammation, and the potential for therapeutic immune checkpoint modulation in inflammatory cerebrovascular disorders. A search of Pubmed and clinicaltrials.gov was performed to find relevant literature published within the last 50 years.Expert opinion: The clinical success of immune-activating checkpoint modulators in human cancers has shown the immense clinical potential of checkpoint-based immunotherapy. Given that checkpoint blockade can also precipitate a pathologic pro-inflammatory or autoimmune response, it is plausible that these pathways may also be targeted to quell aberrant inflammation. A limited but growing number of studies suggest that immune checkpoints play a critical role in regulating the immune response in the central nervous system in a variety of contexts, and that immune-deactivating checkpoint modulators may be a promising treatment strategy for acute and chronic neuroinflammation in cerebrovascular disorders.

Circulating Treg cells from patients with cerebral aneurysms displayed deficiency in ICOS expression and function

Inducible costimulator (ICOS) is a member of the CD28 family. When activated, ICOS signalling promotes FOXP3 CNS2 gene demethylation and stabilizes Treg differentiation. Cerebral aneurysm (CA) is the local ballooning of the cerebral vasculature, characterized by higher levels of inflammation mediators and tissue remodelling. FOXP3⁺ Treg cell dysfunction may contribute to CA pathogenesis. In this study, the expression and function of ICOS in Treg cells was investigated. Circulating CD4⁺ CD25^hi T cells from CA subjects demonstrated significantly lower levels of ICOS expression than circulating CD4⁺ CD25^hi T cells from healthy subjects. In both healthy subjects and CA subjects, FOXP3⁺ Treg cells were highly concentrated in the ICOS⁺ fraction of CD4⁺ CD25^hi T cells. Anti-ICOS costimulation, in combination with anti-CD3 and IL-2, significantly increased FOXP3 expression in CD4⁺ CD25^hi ICOS⁺ T cells but not in CD4⁺ CD25^hi ICOS^- T cells. In addition, anti-CD3/IL-2 and anti-ICOS costimulation significantly elevated the expression of IL-10 and TGF-β, decreased the expression of IL-17, and enhanced CD4⁺ CD25^hi ICOS⁺ T cell-mediated suppression of autologous CD4⁺ CD25^- Tconv proliferation. Interestingly, CD4⁺ CD25^hi ICOS⁺ T cells from CA subjects presented lower responsiveness toward anti-ICOS costimulation than CD4⁺ CD25^hi ICOS⁺ T cells from healthy subjects. Overall, these results demonstrated that ICOS signalling could significantly improve FOXP3 expression and enhance Treg functional potency. However, circulating Treg cells from CA patients displayed reduced ICOS expression and lower responsiveness toward anti-ICOS stimulation.

Significance of TIM3 expression in cancer: From biology to the clinic

Targeting inhibitory immune checkpoint molecules has dramatically changed treatment paradigms in medical oncology. Understanding the best strategies to unleash a pre-existing immune response or to induce an efficient immune response against tumors has emerged as a research priority. In this work, we focus on a novel target for cancer immunotherapy, the inhibitory receptor T-cell immunoglobulin and mucin domain 3 (TIM3). This narrative review describes TIM3 biology in different (tumor-infiltrating) immune cells, particularly in the immunosuppressive regulatory T cells and dysfunctional/exhausted cytotoxic T lymphocytes, but also in cells that confer innate immunity - natural killer and dendritic cells. We discuss the functional role of TIM3, its expression and its clinical significance in a variety of tumors, and confront the heterogeneous results emerging from different studies, including clinical trials of immunotherapy. Finally, this work summarizes the principal early-phase clinical trials exploring TIM3 blockade and discusses some future perspectives.