Endothelial Ribonuclease 1 in Cardiovascular and Systemic Inflammation

Effects of in utero exposure to Δ-9-tetrahydrocannabinol on cardiac extracellular matrix expression and vascular transcriptome in rhesus macaques

Delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis, remains a schedule I substance, thus safety data regarding the effects on the cardiovascular and prenatal health are limited. Importantly, there is evidence showing prenatal cannabis exposure can negatively impact fetal organ development, including the cardiovascular system. THC can cross the placenta and bind to cannabinoid receptors expressed in the developing fetus, including on endothelial cells. To understand the impact of prenatal THC exposure on the fetal cardiovascular system, we used our rhesus macaque model of prenatal daily edible THC consumption. Before conception, animals were acclimated to THC (2.5 mg/7 kg/day, equivalent to a heavy medical cannabis dose) and maintained on this dose daily throughout pregnancy. Fetal tissue samples were collected at gestational day 155 (full term is 168 days). Our model showed that in utero THC exposure was associated with a decreased heart weight-to-body weight ratio in offspring, warranting further mechanistic investigation. Histological examination of the fetal cardiac and vascular tissues did not reveal any significant effect of THC exposure on the maturity of collagen within the fetal heart or the aorta. Total collagen III expression and elastin production and organization were unchanged. However, bulk RNA-sequencing of vascular cells in the umbilical vein, umbilical artery, and fetal aorta demonstrated that THC alters the fetal vascular transcriptome and is associated with upregulated expression of genes involved in carbohydrate metabolism and inflammation. The long-term consequences of these findings are unknown but suggest that prenatal THC exposure may affect cardiovascular development in offspring.NEW & NOTEWORTHY Prenatal cannabis use is increasing and despite the public health relevance, there is limited safety data regarding its impact on offspring cardiovascular health outcomes. We used a translational, nonhuman primate model of daily edible Δ-9-tetrahydrocannabinol (THC) consumption during pregnancy to assess its effects on the fetal cardiovascular system. THC-exposed fetal vascular tissues displayed upregulation of genes involved in cellular metabolism and inflammation, suggesting that prenatal THC exposure may impact fetal vascular tissues.

Nucleic acid degradation as barrier to gene delivery: a guide to understand and overcome nuclease activity

Gene therapy is on its way to revolutionize the treatment of both inherited and acquired diseases, by transferring nucleic acids to correct a disease-causing gene in the target cells of patients. In the fight against infectious diseases, mRNA-based therapeutics have proven to be a viable strategy in the recent Covid-19 pandemic. Although a growing number of gene therapies have been approved, the success rate is limited when compared to the large number of preclinical and clinical trials that have been/are being performed. In this review, we highlight some of the hurdles which gene therapies encounter after administration into the human body, with a focus on nucleic acid degradation by nucleases that are extremely abundant in mammalian organs, biological fluids as well as in subcellular compartments. We overview the available strategies to reduce the biodegradation of gene therapeutics after administration, including chemical modifications of the nucleic acids, encapsulation into vectors and co-administration with nuclease inhibitors and discuss which strategies are applied for clinically approved nucleic acid therapeutics. In the final part, we discuss the currently available methods and techniques to qualify and quantify the integrity of nucleic acids, with their own strengths and limitations.

Screening of potential biomarkers of system lupus erythematosus based on WGCNA and machine learning algorithms

Systemic lupus erythematosus (SLE) is an autoimmune disease involving multiple systems. Its recurrent episodes and fluctuating disease courses have a severe impact on patients. Biomarkers to predict disease prognosis and remission are still lacking in SLE. We downloaded the GSE50772 dataset from the Gene Expression Omnibus database and identified differentially expressed genes (DEGs) between SLE and healthy controls. Weighted gene co-expression network analysis was used to identify key gene modules and corresponding genes in SLE. The overlapped genes in DEGs and key modules are used as key genes for subsequent analysis. These key genes were analyzed using 3 machine learning algorithms, including the least absolute shrinkage and selection operator, support vector machine recursive elimination, and random forest algorithms. The overlapped genes were obtained as potential biomarkers for further analysis, investigating and validating the potential biomarkers' possible functions, regulatory mechanisms, diagnostic value, and expression levels. And finally studied the differences between groups in level of immune cell infiltration and explored the relationship between potential biomarkers and immunity. A total of 234 overlapped genes in DEGs and key modules are used as key genes for subsequent analysis. After taking the intersection of the key genes obtained by 3 algorithms, we got 4 potential biomarkers (ARID2, CYSTM1, DDIT3, and RNASE1) with high diagnostic values. Finally, further immune infiltration analysis showed differences in various immune cells in the SLE and healthy control samples. ARID2, CYSTM1, DDIT3, and RNASE1 can affect the immune function of SLE patients. ARID2, CYSTM1, DDIT3, and RNASE1 could be used as immune-related potential biomarkers and therapeutic or diagnostic targets for further research.

Single-cell profiling reveals inflammatory polarization of human carotid versus femoral plaque leukocytes

Femoral atherosclerotic plaques are less inflammatory than carotid plaques histologically, but limited cell-level data exist regarding comparative immune landscapes and polarization at these sites. We investigated intraplaque leukocyte phenotypes and transcriptional polarization in 49 patients undergoing femoral (n = 23) or carotid (n = 26) endarterectomy using single-cell RNA-Seq (scRNA-Seq; n = 13), flow cytometry (n = 24), and IHC (n = 12). Comparative scRNA-Seq of CD45+-selected leukocytes from femoral (n = 9; 35,265 cells) and carotid (n = 4; 30,655 cells) plaque revealed distinct transcriptional profiles. Inflammatory foam cell-like macrophages and monocytes comprised higher proportions of myeloid cells in carotid plaques, whereas noninflammatory foam cell-like macrophages and LYVE1-overexpressing macrophages comprised higher proportions of myeloid cells in femoral plaque (P < 0.001 for all). A significant comparative excess of CCR2+ macrophages in carotid versus plaque was observed by flow cytometry in a separate validation cohort. B cells were more prevalent and exhibited a comparatively antiinflammatory profile in femoral plaque, whereas cytotoxic CD8+ T cells were more prevalent in carotid plaque. In conclusion, human femoral plaques exhibit distinct macrophage phenotypic and transcriptional profiles as well as diminished CD8+ T cell populations compared with human carotid plaques.

Effect of Extracellular Ribonucleic Acids on Neurovascularization in Osteoarthritis

Osteoarthritis is a degenerative disease characterized by abnormal neurovascularization at the osteochondral junctions, the regulatory mechanisms of which remain poorly understood. In the present study, a murine osteoarthritic model with augmented neurovascularization at the osteochondral junction is used to examine this under-evaluated facet of degenerative joint dysfunction. Increased extracellular RNA (exRNA) content is identified in neurovascularized osteoarthritic joints. It is found that the amount of exRNA is positively correlated with the extent of neurovascularization and the expression of vascular endothelial growth factor (VEGF). In vitro binding assay and molecular docking demonstrate that synthetic RNAs bind to VEGF via electrostatic interactions. The RNA-VEGF complex promotes the migration and function of endothelial progenitor cells and trigeminal ganglion cells. The use of VEGF and VEGFR2 inhibitors significantly inhibits the amplification of the RNA-VEGF complex. Disruption of the RNA-VEGF complex by RNase and polyethyleneimine reduces its in vitro activities, as well as prevents excessive neurovascularization and osteochondral deterioration in vivo. The results of the present study suggest that exRNAs may be potential targets for regulating nerve and blood vessel ingrowth under physiological and pathological joint conditions.

Positive and negative regulation of the Fcγ receptor-stimulating activity of RNA-containing immune complexes by RNase

The U1RNP complex, Ro/SSA, and La/SSB are major RNA-containing autoantigens. Immune complexes (ICs) composed of RNA-containing autoantigens and autoantibodies are suspected to be involved in the pathogenesis of some systemic autoimmune diseases. Therefore, RNase treatment, which degrades RNA in ICs, has been tested in clinical trials as a potential therapeutic agent. However, no studies to our knowledge have specifically evaluated the effect of RNase treatment on the Fcγ receptor-stimulating (FcγR-stimulating) activity of RNA-containing ICs. In this study, using a reporter system that specifically detects FcγR-stimulating capacity, we investigated the effect of RNase treatment on the FcγR-stimulating activity of RNA-containing ICs composed of autoantigens and autoantibodies from patients with systemic autoimmune diseases such as systemic lupus erythematosus. We found that RNase enhanced the FcγR-stimulating activity of Ro/SSA- and La/SSB-containing ICs, but attenuated that of the U1RNP complex-containing ICs. RNase decreased autoantibody binding to the U1RNP complex, but increased autoantibody binding to Ro/SSA and La/SSB. Our results suggest that RNase enhances FcγR activation by promoting the formation of ICs containing Ro/SSA or La/SSB. Our study provides insights into the pathophysiology of autoimmune diseases involving anti-Ro/SSA and anti-La/SSB autoantibodies, and into the therapeutic application of RNase treatment for systemic autoimmune diseases.

Bacterial extracellular vesicles repress the vascular protective factor RNase1 in human lung endothelial cells

BACKGROUND

Sepsis is one of the leading causes of death worldwide and characterized by blood stream infections associated with a dysregulated host response and endothelial cell (EC) dysfunction. Ribonuclease 1 (RNase1) acts as a protective factor of vascular homeostasis and is known to be repressed by massive and persistent inflammation, associated to the development of vascular pathologies. Bacterial extracellular vesicles (bEVs) are released upon infection and may interact with ECs to mediate EC barrier dysfunction. Here, we investigated the impact of bEVs of sepsis-related pathogens on human EC RNase1 regulation.

METHODS

bEVs from sepsis-associated bacteria were isolated via ultrafiltration and size exclusion chromatography and used for stimulation of human lung microvascular ECs combined with and without signaling pathway inhibitor treatments.

RESULTS

bEVs from Escherichia coli, Klebsiella pneumoniae and Salmonella enterica serovar Typhimurium significantly reduced RNase1 mRNA and protein expression and activated ECs, while TLR2-inducing bEVs from Streptococcus pneumoniae did not. These effects were mediated via LPS-dependent TLR4 signaling cascades as they could be blocked by Polymyxin B. Additionally, LPS-free ClearColi™ had no impact on RNase1. Further characterization of TLR4 downstream pathways involving NF-кB and p38, as well as JAK1/STAT1 signaling, revealed that RNase1 mRNA regulation is mediated via a p38-dependent mechanism.

CONCLUSION

Blood stream bEVs from gram-negative, sepsis-associated bacteria reduce the vascular protective factor RNase1, opening new avenues for therapeutical intervention of EC dysfunction via promotion of RNase1 integrity. Video Abstract.

Single-cell transcriptomics for the assessment of cardiac disease

Cardiovascular disease is the leading cause of death globally. An advanced understanding of cardiovascular disease mechanisms is required to improve therapeutic strategies and patient risk stratification. State-of-the-art, large-scale, single-cell and single-nucleus transcriptomics facilitate the exploration of the cardiac cellular landscape at an unprecedented level, beyond its descriptive features, and can further our understanding of the mechanisms of disease and guide functional studies. In this Review, we provide an overview of the technical challenges in the experimental design of single-cell and single-nucleus transcriptomics studies, as well as a discussion of the type of inferences that can be made from the data derived from these studies. Furthermore, we describe novel findings derived from transcriptomics studies for each major cardiac cell type in both health and disease, and from development to adulthood. This Review also provides a guide to interpreting the exhaustive list of newly identified cardiac cell types and states, and highlights the consensus and discordances in annotation, indicating an urgent need for standardization. We describe advanced applications such as integration of single-cell data with spatial transcriptomics to map genes and cells on tissue and define cellular microenvironments that regulate homeostasis and disease progression. Finally, we discuss current and future translational and clinical implications of novel transcriptomics approaches, and provide an outlook of how these technologies will change the way we diagnose and treat heart disease.

Integrated Analysis of Tracheobronchial Fluid from Before and After Cardiopulmonary Bypass Reveals Activation of the Integrated Stress Response and Altered Pulmonary Microvascular Permeability

Objective: We aim to comprehensively describe the transcriptional activity and signaling of pulmonary parenchymal and immune cells before and after cardiopulmonary bypass (CPB) by using a multi-omic approach coupled with functional cellular assays. We hypothesize that key signaling pathways from specific cells within the lung alter pulmonary endothelial cell function resulting in worsening or improving disease. Methods: We collected serial tracheobronchial lavage samples from intubated patients less than 2-years-old undergoing surgery with CPB. Samples were immediately processed for single cell RNA sequencing (10x Genomics). Cell clustering, cell-type annotation, and visualization were performed, and differentially expressed genes (DEG) between serial samples were identified. Metabolomic and proteomic analyses were performed on the supernatant using mass spectrometry and a multiplex assay (SomaScan) respectively. Functional assays were done using electric cell-substrate impedance sensing to measure resistance across human pulmonary microvascular endothelial cells (HPMECs). Results: Analysis of eight patients showed a heterogeneous mixture of pulmonary parenchymal and immune cells. Cell clustering demonstrated time-dependent changes in the transcriptomic signature indicating altered cellular phenotypes after CPB. DEG analysis was represented by genes involved in host defense, innate immunity, and the mitochondrial respiratory transport chain. Ingenuity pathway analysis showed upregulation of the integrated stress response across all cell types after CPB. Metabolomic analysis demonstrated upregulation of ascorbate and aldarate metabolism. Unbiased proteomic analysis revealed upregulation of proteins involved in cytokine and chemokine pathways. Post-CPB patient supernatant improved HMPEC barrier function, suggesting a protective cellular response to CPB. Conclusion: Children who undergo CPB for cardiac surgery have distinct cell populations, transcriptional activity, and metabolism that change over time. The response to ischemia-reperfusion injury in the lower airway of children appears to be protective, with the need to identify potential targets through future investigations.

Transcriptome-wide analysis reveals the coregulation of RNA-binding proteins and alternative splicing genes in the development of atherosclerosis

RNA-binding proteins (RBPs) are involved in the regulation of RNA splicing, stability, and localization. How RBPs control the development of atherosclerosis, is not fully understood. To explore the relevant RNA-binding proteins (RBPs) and alternative splicing events (ASEs) in atherosclerosis. We made a comprehensive work to integrate analyses of differentially expressed genes, including differential RBPs, and variable splicing characteristics related to different stages of atherosclerosis in dataset GSE104140. A total of 3712 differentially expressed genes (DEGs) were identified, including 2921 upregulated genes and 791 downregulated genes. Further analysis screened out 54 RBP genes, and 434 AS genes overlapped DEGs. We selected high expression ten RBP genes (SAMHD1, DDX60 L, TLR7, RBM47, MYEF2, RNASE6, PARP12, APOBEC3G, SMAD9, and RNASE1) for co-expression analysis. Meanwhile, we found seven regulated alternative splicing genes (RASGs) (ABI1, FXR1, CHID1, PLEC, PRKACB, BNIP2, PPP3CB) that could be regulated by RBPs. The co-expression network was used to further elucidate the regulatory and interaction relationship between RBPs and AS genes. Apoptotic process and innate immune response, revealed by the functional enrichment analysis of RASGs regulated by RBPs were closely related to atherosclerosis. In addition, 26 of the 344 alternative splicing genes regulated by the above 10 RBPs were transcription factors (TFs), We selected high expression nine TFs (TFDP1, RBBP7, STAT2, CREB5, ERG, ELF1, HMGN3, BCLAF1, and ZEB2) for co-expression analysis. The target genes of these TFs were mainly enriched in inflammatory and immune response pathways that were associated with atherosclerosis. indicating that AS abnormalities of these TFs may have a function in atherosclerosis. Furthermore, the expression of differentially expressed RBPs and the alternative splicing events of AS genes was validated by qRT-PCR in umbilical vein endothelial cells (HUVEC). The results showed that RBM47 were remarkedly difference in HUVEC treated with ox-LDL and the splicing ratio of AS in BCLAF1which is regulated by RBM47 significantly changed. In conclusion, the differentially expressed RBPs identified in our analysis may play important roles in the development of atherosclerosis by regulating the AS of these TF genes.

The role of human ribonuclease A family in health and diseases: A systematic review

The ribonuclease A (RNase A) family is one of the best-characterized vertebrate-specific proteins. In humans, eight catalytically active RNases (numbered 1–8) have been identified and have unique tissue distributions. Apart from the digestion of dietary RNA, a broad range of biological actions, including the regulation of intra- or extra-cellular RNA metabolism as well as antiviral, antibacterial, and antifungal activities, neurotoxicity, promotion of cell proliferation, anti-apoptosis, and immunomodulatory abilities, have been recently reported for the members of this family. Based on multiple biological roles, RNases are found to participate in the pathogenic processes of many diseases, such as infection, immune dysfunction, neurodegeneration, cancer, and cardiovascular disorders. This review summarizes the available data on the human RNase A family and illustrates the significant roles of the eight canonical RNases in health and disease, for stimulating further basic research and development of ideas on the potential solutions for disease diagnosis and treatment.

Identification of novel tumor microenvironment-associated genes in gastric cancer based on single-cell RNA-sequencing datasets

Tumor microenvironment and heterogeneity play vital roles in the development and progression of gastric cancer (GC). In the past decade, a considerable amount of single-cell RNA-sequencing (scRNA-seq) studies have been published in the fields of oncology and immunology, which improve our knowledge of the GC immune microenvironment. However, much uncertainty still exists about the relationship between the macroscopic and microscopic data in transcriptomics. In the current study, we made full use of scRNA-seq data from the Gene Expression Omnibus database (GSE134520) to identify 25 cell subsets, including 11 microenvironment-related cell types. The MIF signaling pathway network was obtained upon analysis of receptor–ligand pairs and cell–cell interactions. By comparing the gene expression in a wide variety of cells between intestinal metaplasia and early gastric cancer, we identified 64 differentially expressed genes annotated as immune response and cellular communication. Subsequently, we screened these genes for prognostic clinical value based on the patients’ follow-up data from The Cancer Genome Atlas. TMPRSS15, VIM, APOA1, and RNASE1 were then selected for the construction of LASSO risk scores, and a nomogram model incorporating another five clinical risk factors was successfully created. The effectiveness of least absolute shrinkage and selection operator risk scores was validated using gene set enrichment analysis and levels of immune cell infiltration. These findings will drive the development of prognostic evaluations affected by the immune tumor microenvironment in GC.

SIRT6 mediates MRTF-A deacetylation in vascular endothelial cells to antagonize oxLDL-induced ICAM-1 transcription

Oxidized low-density lipoprotein (oxLDL), a known risk factor for atherosclerosis, activates the transcription of adhesion molecules (ICAM-1) in endothelial cells. We previously showed that myocardin-related transcription factor A (MRTF-A) mediates oxLDL-induced ICAM-1 transcription. Here we confirm that ICAM-1 transactivation paralleled dynamic alterations in MRTF-A acetylation. Since treatment with the antioxidant NAC dampened MRTF-A acetylation, MRTF-A acetylation appeared to be sensitive to cellular redox status. Of interest, silencing of SIRT6, a lysine deacetylase, restored MRTF-A acetylation despite the addition of NAC. SIRT6 directly interacted with MRTF-A to modulate MRTF-A acetylation. Deacetylation of MRTF-A by SIRT6 led to its nuclear expulsion thus dampening MRTF-A occupancy on the ICAM-1 promoter. Moreover, SIRT6 expression was downregulated with oxLDL stimulation likely owing to promoter hypermethylation in endothelial cells. DNA methyltransferase 1 (DNMT1) was recruited to the SIRT6 promoter and mediated SIRT6 repression. The ability of DNMT1 to repress SIRT6 promoter partly was dependent on ROS-sensitive serine 154 phosphorylation. In conclusion, our data unveil a novel DNMT1-SIRT6 axis that contributes to the regulation of MRTF-A acetylation and ICAM-1 transactivation in endothelial cells.

Advances in Nanomaterials for Injured Heart Repair

Atherosclerotic cardiovascular disease (ASCVD) is one of the leading causes of mortality worldwide. Because of the limited regenerative capacity of adult myocardium to compensate for the loss of heart tissue after ischemic infarction, scientists have been exploring the possible mechanisms involved in the pathological process of ASCVD and searching for alternative means to regenerate infarcted cardiac tissue. Although numerous studies have pursued innovative solutions for reversing the pathological process of ASCVD and improving the effectiveness of delivering therapeutics, the translation of those advances into downstream clinical applications remains unsatisfactory because of poor safety and low efficacy. Recently, nanomaterials (NMs) have emerged as a promising new strategy to strengthen both the efficacy and safety of ASCVD therapy. Thus, a comprehensive review of NMs used in ASCVD treatment will be useful. This paper presents an overview of the pathophysiological mechanisms of ASCVD and the multifunctional mechanisms of NM-based therapy, including antioxidative, anti-inflammation and antiapoptosis mechanisms. The technological improvements of NM delivery are summarized and the clinical transformations concerning the use of NMs to treat ASCVD are examined. Finally, this paper discusses the challenges and future perspectives of NMs in cardiac regeneration to provide insightful information for health professionals on the latest advancements in nanotechnologies for ASCVD treatment.

Extracellular RNA as a Versatile DAMP and Alarm Signal That Influences Leukocyte Recruitment in Inflammation and Infection

Upon vascular injury, tissue damage, ischemia, or microbial infection, intracellular material such as nucleic acids and histones is liberated and comes into contact with the vessel wall and circulating blood cells. Such "Danger-associated molecular patterns" (DAMPs) may thus have an enduring influence on the inflammatory defense process that involves leukocyte recruitment and wound healing reactions. While different species of extracellular RNA (exRNA), including microRNAs and long non-coding RNAs, have been implicated to influence inflammatory processes at different levels, recent in vitro and in vivo work has demonstrated a major impact of ribosomal exRNA as a prominent DAMP on various steps of leukocyte recruitment within the innate immune response. This includes the induction of vascular hyper-permeability and vasogenic edema by exRNA via the activation of the "vascular endothelial growth factor" (VEGF) receptor-2 system, as well as the recruitment of leukocytes to the inflamed endothelium, the M1-type polarization of inflammatory macrophages, or the role of exRNA as a pro-thrombotic cofactor to promote thrombosis. Beyond sterile inflammation, exRNA also augments the docking of bacteria to host cells and the subsequent microbial invasion. Moreover, upon vessel occlusion and ischemia, the shear stress-induced release of exRNA initiates arteriogenesis (i.e., formation of natural vessel bypasses) in a multistep process that resembles leukocyte recruitment. Although exRNA can be counteracted for by natural circulating RNase1, under the conditions mentioned, only the administration of exogenous, thermostable, non-toxic RNase1 provides an effective and safe therapeutic regimen for treating the damaging activities of exRNA. It remains to be investigated whether exRNA may also influence viral infections (including COVID-19), e.g., by supporting the interaction of host cells with viral particles and their subsequent invasion. In fact, as a consequence of the viral infection cycle, massive amounts of exRNA are liberated, which can provoke further tissue damage and enhance virus dissemination. Whether the application of RNase1 in this scenario may help to limit the extent of viral infections like COVID-19 and impact on leukocyte recruitment and emigration steps in immune defense in order to limit the extent of associated cardiovascular diseases remains to be studied.