Endothelial ARHGEF26 is an angiogenic factor promoting VEGF signalling

Transcriptomics-Based Study of Immune Genes Associated with Subclinical Mastitis in Bactrian Camels

The significant increase in demand for camel milk has led to a rapid increase in the number of Bactrian camels. However, the widespread occurrence of mastitis significantly impacts the development of the Bactrian camel milk industry and poses a public health risk. Despite this, there is a lack of research on the transcriptional response, immune response pathways, and changes in core genes of Bactrian camels with subclinical mastitis. This study aimed to reveal the changes in immune-related response pathways and gene transcription levels in Bactrian camels with subclinical mastitis by analyzing the blood transcriptional response after the occurrence of subclinical mastitis in natural conditions. This study focused on 7-year-old Bactrian camels and collected 2 mL of blood from the camels that tested positive with a 4-peak California Mastitis Test (CMT) and those that tested negative with a 3-peak CMT. RNA sequencing (RNA-Seq) technology was used to analyze gene expression in the blood samples. Gene expression was verified using quantitative reverse transcription polymerase chain reaction (RT-qPCR). Overall, 1722 differentially expressed genes were sequenced in the blood samples of CMT-positive and CMT-negative Bactrian camels, including 1061 upregulated and 661 downregulated genes. After conducting gene ontology functional enrichment, 453 differentially expressed genes were identified. We also discovered pathways such as immune response, the G-protein-coupled receptor signaling pathway, and internal signal transmission. Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway enrichment detected 668 differentially expressed genes annotated onto 309 metabolic pathways, with significantly enriched immune pathways including cytokine-cytokine receptor interaction, complex and coalescence cascades, natural killer cell-mediated cytotoxicity, and T helper type 17 cell differentiation, among others. Through a STRING protein interaction database and cytoscape analysis, it was found that core differentially expressed genes related to immunity included IL10, CCL5, IL1B, OSM, TNFRSF1B, IL7, and CCR3, among others. The RT-qPCR results for six randomly selected core differentially expressed genes showed that the RT-qPCR expression pattern was consistent with the RNA Seq results. The immune-related genes in Bactrian camels affected by subclinical mastitis are primarily concentrated in the immune response and the cytokine-cytokine receptor interaction pathway. Given the importance of these pathways and the connections among related genes, the immune genes within these pathways may play a crucial role in the pathogenesis of subclinical mastitis in Bactrian camels. This study provides a valuable reference for investigating the immune regulatory mechanisms of subclinical mastitis in Bactrian camels.

Epigenetic drug screening identifies enzyme inhibitors A-196 and TMP-269 as novel regulators of sprouting angiogenesis

Epigenetic therapy has gained interest in treating cardiovascular diseases, but preclinical studies often encounter challenges with cell-type-specific effects or batch-to-batch variation, which have limited identification of novel drug candidates targeting angiogenesis. To address these limitations and improve the reproducibility of epigenetic drug screening, we redesigned a 3D in vitro fibrin bead assay to utilize immortalized human aortic endothelial cells (TeloHAECs) and screened a focused compound library with 105 agents. Compared to the established model using primary human umbilical vein endothelial cells, TeloHAECs needed a higher-density fibrin gel for optimal sprouting, successfully forming sprouts under both normoxic and hypoxic cell culture conditions. We identified two epigenetic enzyme inhibitors as novel regulators of sprouting angiogenesis: A196, a selective SUV4-20H1/H2 inhibitor, demonstrated pro-angiogenic effects through increased H4K20me1 levels and upregulation of cell cycle associated genes, including MCM2 and CDK4. In contrast TMP-269, a selective class IIa HDAC inhibitor, exhibited anti-angiogenic effects by downregulating angiogenesis-related proteins and upregulating pro-inflammatory signaling. These findings highlight the suitability of the modified TeloHAEC fibrin bead assay for drug screening purposes and reveal both pro-angiogenic and anti-angiogenic drug candidates with therapeutic potential.

Unraveling the causal impact of smoking and its DNA methylation signatures on cardiovascular disease: Mendelian randomization and colocalization analysis

BACKGROUND

To explore the mechanisms linking smoking to cardiovascular diseases (CVDs) from an epigenetic perspective.

METHODS

Mendelian Randomization (MR) analysis was performed to assess the causal effects of smoking behavior and DNA methylation levels at smoking-related CpG sites on nine CVDs, including aortic aneurysm, atrial fibrillation, coronary atherosclerosis, coronary heart disease, heart failure, intracerebral hemorrhage, ischemic stroke, myocardial infarction, subarachnoid hemorrhage. Colocalization analysis was used to further identify key smoking-related CpG sites from the MR causal estimates. Reactome enrichment analysis was used to elucidate the potential mechanisms.

RESULTS

MR analysis indicates that smoking behaviors are significantly associated with an increased risk of nine CVDs (OR > 1, P < 0.05). Through MR and colocalization analysis, five key smoking-related CpG sites were ultimately determined. DNA methylation alteration at cg25313468 (located in the TSS1500 region of REST) is simultaneously associated with the risk of atrial fibrillation, coronary atherosclerosis, coronary heart disease, and myocardial infarction. Additionally, cg21647257 (located in the TSS200 region of CLIP3) is associated with the risk of atrial fibrillation; cg06197751 (located in SGEF gene body) and cg07520810 (located in ARID5B gene body) are associated with the risk of coronary atherosclerosis; cg16822035 (located in MCF2L gene body) is associated with the risk of myocardial infarction. Enrichment analysis suggests that phosphatase and tensin homologue (PTEN) may be involved in the downstream mechanisms of cg25313468 (REST).

CONCLUSION

This study uncovers the relationship between smoking, DNA methylation, and CVDs, providing new insights into the pathogenic effect of smoking on CVDs from an epigenetic perspective.

Dexamethasone induces trabecular meshwork cell myofibroblast transdifferentiation through ARHGEF26

Glucocorticoid use may cause elevated intraocular pressure, leading to the development of glucocorticoid-induced glaucoma (GIG). However, the mechanism of GIG development remains incompletely understood. In this study, we subjected primary human trabecular meshwork cells (TMCs) and mice to dexamethasone treatment to mimic glucocorticoid exposure. The myofibroblast transdifferentiation of TMCs was observed in cellular and mouse models, as well as in human trabecular mesh specimens. This was demonstrated by the cytoskeletal reorganization, alterations in cell morphology, heightened transdifferentiation markers, increased extracellular matrix deposition, and cellular dysfunction. Knockdown of Rho guanine nucleotide exchange factor 26 (ARHGEF26) expression ameliorated dexamethasone-induced changes in cell morphology and upregulation of myofibroblast markers, reversed dysfunction and extracellular matrix deposition in TMCs, and prevented the development of dexamethasone-induced intraocular hypertension. And, this process may be related to the TGF-β pathway. In conclusion, glucocorticoids induced the myofibroblast transdifferentiation in TMCs, which played a crucial role in the pathogenesis of GIG. Inhibition of ARHGEF26 expression protected TMCs by reversing myofibroblast transdifferentiation. This study demonstrated the potential of reversing the myofibroblast transdifferentiation of TMCs as a new target for treating GIG.

A Splice Form of VEGF, a Potential Anti-Angiogenetic Form of Head and Neck Squamous Cell Cancer Inhibition

Angiogenesis, primarily mediated by vascular endothelial growth factor (VEGF), is a fundamental step in the progression and metastasis of head and neck squamous cell carcinoma (HNSCC). Traditional anti-angiogenic therapies that target the VEGF pathway have shown promise but are often associated with significant side effects and variable efficacy due to the complexity of the angiogenic signaling pathway. This review highlights the potential of a specific VEGF splice form, VEGF165b, as an innovative therapeutic target for HNSCC. VEGF165b, unlike standard VEGF, is a natural inhibitor that binds to VEGF receptors without triggering pro-angiogenic signaling. Its distinct molecular structure and behavior suggest ways to modulate angiogenesis. This concept is particularly relevant when studying HNSCC, as introducing VEGF165b's anti-angiogenic properties offers a novel approach to understanding and potentially influencing the disease's dynamics. The review synthesizes experimental evidence suggesting the efficacy of VEGF165b in inhibiting tumor-induced angiogenesis and provides insight into a novel therapeutic strategy that could better manage HNSCC by selectively targeting aberrant vascular growth. This approach not only provides a potential pathway for more targeted and effective treatment options but also opens the door to a new paradigm in anti-angiogenic therapy with the possibility of reduced systemic toxicity. Our investigation is reshaping the future of HNSCC treatment by setting the stage for future research on VEGF splice variants as a tool for personalized medicine.

CD8+ T Cells Drive Plaque Smooth Muscle Cell Dedifferentiation in Experimental Atherosclerosis

BACKGROUND

Atherosclerosis is driven by the infiltration of the arterial intima by diverse immune cells and smooth muscle cells (SMCs). CD8+ T cells promote lesion growth during atherosclerotic lesion development, but their role in advanced atherosclerosis is less clear. Here, we studied the role of CD8+ T cells and their effects on SMCs in established atherosclerosis.

METHODS

CD8+ T cells were depleted in (SMC reporter) low-density lipoprotein receptor-deficient (Ldlr-/-) mice with established atherosclerotic lesions. Atherosclerotic lesion formation was examined, and single-cell RNA sequencing of aortic SMCs and their progeny was performed. Additionally, coculture experiments with primary aortic SMCs and CD8+ T cells were conducted.

RESULTS

Although we could not detect differences in atherosclerotic lesion size, an increased plaque SMC content was noted in mice after CD8+ T-cell depletion. Single-cell RNA sequencing of aortic lineage-traced SMCs revealed contractile SMCs and a modulated SMC cluster, expressing macrophage- and osteoblast-related genes. CD8+ T-cell depletion was associated with an increased contractile but decreased macrophage and osteoblast-like gene signature in this modulated aortic SMC cluster. Conversely, exposure of isolated aortic SMCs to activated CD8+ T cells decreased the expression of genes indicative of a contractile SMC phenotype and induced a macrophage and osteoblast-like cell state. Notably, CD8+ T cells triggered calcium deposits in SMCs under osteogenic conditions. Mechanistically, we identified transcription factors highly expressed in modulated SMCs, including Runx1, to be induced by CD8+ T cells in cultured SMCs in an IFNγ (interferon-γ)-dependent manner.

CONCLUSIONS

We here uncovered CD8+ T cells to control the SMC phenotype in atherosclerosis. CD8+ T cells promote SMC dedifferentiation and drive SMCs to adopt features of macrophage-like and osteoblast-like, procalcifying cell phenotypes. Given the critical role of SMCs in atherosclerotic plaque stability, CD8+ T cells could thus be explored as therapeutic target cells during lesion progression.

The Role of Endothelial Cells in Atherosclerosis: Insights from Genetic Association Studies

Endothelial cells (ECs) mediate several biological functions that are relevant to atherosclerosis and coronary artery disease (CAD), regulating an array of vital processes including vascular tone, wound healing, reactive oxygen species, shear stress response, and inflammation. Although which of these functions is linked causally with CAD development and/or progression is not yet known, genome-wide association studies have implicated more than 400 loci associated with CAD risk, among which several have shown EC-relevant functions. Given the arduous process of mechanistically interrogating single loci to CAD, high-throughput variant characterization methods, including pooled Clustered Regularly Interspaced Short Palindromic Repeats screens, offer exciting potential to rapidly accelerate the discovery of bona fide EC-relevant genetic loci. These discoveries in turn will broaden the therapeutic avenues for CAD beyond lipid lowering and behavioral risk modification to include EC-centric modalities of risk prevention and treatment.