Background
T‐cell activation is associated with an adverse outcome in COVID‐19, but whether T‐cell activation and exhaustion relate to persistent respiratory dysfunction and death is unknown.
...Objectives
To investigate whether T‐cell activation and exhaustion persist and are associated with prolonged respiratory dysfunction and death after hospitalization for COVID‐19.
Methods
Plasma and serum from two Norwegian cohorts of hospitalized patients with COVID‐19 (n = 414) were analyzed for soluble (s) markers of T‐cell activation (sCD25) and exhaustion (sTim‐3) during hospitalization and follow‐up.
Results
Both markers were strongly associated with acute respiratory failure, but only sTim‐3 was independently associated with 60‐day mortality. Levels of sTim‐3 remained elevated 3 and 12 months after hospitalization and were associated with pulmonary radiological pathology after 3 months.
Conclusion
Our findings suggest prolonged T‐cell exhaustion is an important immunological sequela, potentially related to long‐term outcomes after severe COVID‐19.
Atherosclerosis and its consequences cause considerable morbidity and mortality world-wide. We have previously shown that expression of the DNA glycosylase NEIL3 is regulated in human atherosclerotic ...plaques, and that NEIL3-deficiency enhances atherogenesis in Apoe
mice. Herein, we identified a time point prior to quantifiable differences in atherosclerosis between Apoe
Neil3
mice and Apoe
mice. Mice at this age were selected to explore the metabolic and pathophysiological processes preceding extensive atherogenesis in NEIL3-deficient mice. Untargeted metabolomic analysis of young Apoe
Neil3
mice revealed significant metabolic disturbances as compared to mice expressing NEIL3, particularly in metabolites dependent on the gut microbiota. 16S rRNA gene sequencing of fecal bacterial DNA indeed confirmed that the NEIL3-deficient mice had altered gut microbiota, as well as increased circulating levels of the bacterially derived molecule LPS. The mice were challenged with a FITC-conjugated dextran to explore gut permeability, which was significantly increased in the NEIL3-deficient mice. Further, immunohistochemistry showed increased levels of the proliferation marker Ki67 in the colonic epithelium of NEIL3-deficient mice, suggesting increased proliferation of intestinal cells and gut leakage. We suggest that these metabolic alterations serve as drivers of atherosclerosis in NEIL3-deficient mice.
Background In cardiovascular diseases, atherosclerotic disorder are the most frequent and important with respect to morbidity and mortality. Inflammation mediated by immune cells is central in all ...parts of the atherosclerotic progress, and further understanding of the underlying mechanisms is needed. Growing evidence suggests that deamination of adenosine‐to‐inosine in RNA is crucial for a correct immune response; nevertheless, the role of adenosine‐to‐inosine RNA editing in atherogenesis has barely been studied. Several proteins have affinity for inosines in RNA, one being ENDOV (endonuclease V), which binds and cleaves RNA at inosines. Data on ENDOV in atherosclerosis are lacking. Methods and Results Quantitative polymerase chain reaction on ENDOV mRNA showed an increased level in human carotid atherosclerotic plaques compared with control veins. Inosine‐ribonuclease activity as measured by an enzyme activity assay is detected in immune cells relevant for the atherosclerotic process. Abolishing EndoV in atherogenic apolipoprotein E‐deficient ( ApoE −/− ) mice reduces the atherosclerotic plaque burden, both in size and lipid content. In addition, in a brain stroke model, mice without ENDOV suffer less damage than control mice. Finally, lack of EndoV reduces the recruitment of monocytes to atherosclerotic lesions in atherogenic ApoE −/− mice. Conclusions ENDOV is upregulated in human atherosclerotic lesions, and data from mice suggest that ENDOV promotes atherogenesis by enhancing the monocyte recruitment into the atherosclerotic lesion, potentially by increasing the effect of CCL2 activation on these cells.
The global risk of cardiovascular disease, including ischemic disease such as stroke, remains high, and cardiovascular disease is the cause of one-third of all deaths worldwide. The main subjacent ...cause, atherosclerosis, is not fully understood. To improve early diagnosis and therapeutic strategies, it is crucial to unveil the key molecular mechanisms that lead to atherosclerosis development. The field of epitranscriptomics is blossoming and quickly advancing in fields like cancer research, nevertheless, poorly understood in the context of cardiovascular disease. Epitranscriptomic modifications are shown to regulate the metabolism and function of RNA molecules, which are important for cell functions such as cell proliferation, a key aspect in atherogenesis. As such, epitranscriptomic regulatory mechanisms can serve as novel checkpoints in gene expression during disease development. In this review, we describe examples of the latest research investigating epitranscriptomic modifications, in particular A-to-I editing and the covalent modification
-methyladenosine and their regulatory proteins, in the context of cardiovascular disease. We additionally discuss the potential of these mechanisms as therapeutic targets and novel treatment options.
Atherogenesis involves a complex interaction between immune cells and lipids, processes greatly influenced by the vascular smooth muscle cell (VSMC) phenotype. The DNA glycosylase NEIL3 has ...previously been shown to have a role in atherogenesis, though whether this is due to its ability to repair DNA damage or to other non-canonical functions is not yet clear. Hereby, we investigate the role of NEIL3 in atherogenesis, specifically in VSMC phenotypic modulation, which is critical in plaque formation and stability.
Chow diet-fed atherosclerosis-prone Apoe−/− mice deficient in Neil3, and NEIL3-abrogated human primary aortic VSMCs were characterized by qPCR, and immunohistochemical and enzymatic-based assays; moreover, single-cell RNA sequencing, mRNA sequencing, and proteomics were used to map the molecular effects of Neil3/NEIL3 deficiency in the aortic VSMC phenotype. Furthermore, BrdU-based proliferation assays and Western blot were performed to elucidate the involvement of the Akt signaling pathway in the transdifferentiation of aortic VSMCs lacking Neil3/NEIL3.
We show that Neil3 deficiency increases atherosclerotic plaque development without affecting systemic lipids. This observation was associated with a shift in VSMC phenotype towards a proliferating, lipid-accumulating and secretory macrophage-like cell phenotype, without changes in DNA damage. VSMC transdifferentiation in Neil3-deficient mice encompassed increased activity of the Akt signaling pathway, supported by cell experiments showing Akt-dependent proliferation in NEIL3-abrogated human primary aortic VSMCs.
Our findings show that Neil3 deficiency promotes atherosclerosis development through non-canonical mechanisms affecting VSMC phenotype involving activation of the Akt signaling pathway.
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•Apoe−/−/Neil3−/− mice develop more atherosclerosis as compared to Apoe−/− mice.•Apoe−/−/Neil3−/− mice display increased medial VSMC area and layer disorganization.•Increased aortic VSMC proliferation in Apoe−/−/Neil3−/− mice and NEIL3-deficient primary human VSMCs.•Neil3 deficiency increases aortic VSMC phenotypic transdifferentiation towards an atherosclerotic macrophage-like cells.•Neil3/NEIL3 deficiency-dependent VSMC proliferation involves activation of the Akt signaling pathway.
We recently showed that interleukin (IL)-6 inhibition by tocilizumab improves myocardial salvage in ST-elevation myocardial infarction (STEMI). However, the mechanisms for this effect are not clear.
...In this exploratory sub-study of the ASSAIL-MI trial, we examined leukocyte differential counts and their relation to myocardial salvage and peak troponin T (TnT) in STEMI patients randomised to tocilizumab (n = 101) or placebo (n = 98). We performed RNA-sequencing on whole blood (n = 40) and T cells (n = 20). B and T cell subpopulations were examined by flow cytometry (n = 69).
(i) STEMI patients had higher neutrophil counts at hospitalisation compared with stable angina patients. (ii) After percutaneous coronary intervention there was a gradual decline in neutrophils, which was significantly more pronounced in the tocilizumab group. (iii) The decrease in neutrophils in the tocilizumab group was associated with improved myocardial salvage and lower peak TnT. (iv) RNA-sequencing suggested that neutrophil function was also attenuated by tocilizumab. (v) B and T cell sub-populations changed only minimally after STEMI with minor effects of tocilizumab, supported as well by RNA-sequencing analyses of T cells. (vi) However, a low CD8+ count was associated with improved myocardial salvage in patients admitted to the hospital > 3 h after symptom onset.
Tocilizumab induced a rapid reduction in neutrophils and seemed to attenuate neutrophil function in STEMI patients potentially related to the beneficial effects of tocilizumab on myocardial salvage.
South-Eastern Norway Regional Health Authority (Nos. 2019067, 2017084), the Central Norway Regional Health Authority and Norwegian Research Council (No. 283867).
More than 170 post-transcriptional RNA modifications regulate the localization, processing and function of cellular RNAs, and aberrant RNA modifications have been linked to a range of human diseases. ...The RNA modification landscape in atherosclerosis, the main underlying cause of cardiovascular diseases, is still largely unknown.
We used mass spectrometry to analyse a selection of RNA-modifying enzymes and the N6-methyladenosine (m6A) in carotid atherosclerotic lesion samples representing early and advanced stages of atherosclerosis as compared to non-atherosclerotic arteries from healthy controls.
(i) the detection of different levels of several enzymes involved in methylations occurring in rRNA and mRNA; (ii) these findings included changes in the levels of methyltransferases (‘writers’), binding proteins (‘readers’) and demethylases (‘erasers’) during atherosclerosis as compared to non-atherosclerotic control arteries, with generally the most prominent differences in samples from early atherosclerotic lesions; and (iii) these changes were accompanied by a marked downregulation of m6A in rRNA, the most abundant and well-studied modification in mRNA with a wide range of effects on cell biology.
We show for the first time that RNA-modifying enzymes and the well-studied RNA modification m6A are differentially regulated in atherosclerotic lesions, which potentially could help creating new prognostic and treatment strategies.
•Post-transcriptional RNA-methylation enzymes are regulated in atherosclerosis.•Levels of m6A are reduced in total RNA from human atherosclerotic samples.•These are the first data showing epitranscriptomic modifications in atherosclerosis.
The objective of this work was on the one hand to assess the antibacterial activity of amines anchored to the external surface of mesoporous silica particles against Listeria monocytogenes in ...comparison with the same dose of free amines as well. It was also our aim to elucidate the mechanism of action of the new antimicrobial device. The suitability of silica nanoparticles to anchor, concentrate and improve the antimicrobial power of polyamines against L. monocytogenes has been demonstrated in a saline solution and in a food matrix. Moreover, through microscope observations it has been possible to determine that the attractive binding forces between the positive amine corona on the surface of nanoparticles and the negatively charged bacteria membrane provoke a disruption of the cell membrane. The surface concentration of amines on the surface of the nanoparticles is so effective that immobilized‐amines were 100 times more effective in killing L. monocytogenes bacteria than the same amount of free polyamines. This novel approach for the creation of antimicrobial nanodevices opens the possibility to put in value the antimicrobial power of natural molecules that have been discarded because of its low antimicrobial power.
Practical Application
Consumers demand for high‐quality products, free from chemical preservatives, with an extended shelf‐life. In this study, a really powerful antimicrobial agent based on a nanomaterial functionalized with a non‐antimicrobial organic molecule was developed as a proof of concept. Following this approach it could be possible to develop a new generation of natural and removable antimicrobials based on their anchoring to functional surfaces for food, agricultural or medical purposes.
Deficiency of NEIL3, a DNA repair enzyme, has significant impact on mouse physiology, including vascular biology and gut health, processes related to aging. Leukocyte telomere length (LTL) is ...suggested as a marker of biological aging, and shortened LTL is associated with increased risk of cardiovascular disease. NEIL3 has been shown to repair DNA damage in telomere regions in vitro. Herein, we explored the role of NEIL3 in telomere maintenance in vivo by studying bone marrow cells from atherosclerosis-prone NEIL3-deficient mice. We found shortened telomeres and decreased activity of the telomerase enzyme in bone marrow cells derived from Apoe−/−Neil3−/− as compared to Apoe−/− mice. Furthermore, Apoe−/−Neil3−/− mice had decreased leukocyte levels as compared to Apoe−/− mice, both in bone marrow and in peripheral blood. Finally, RNA sequencing of bone marrow cells from Apoe−/−Neil3−/− and Apoe−/− mice revealed different expression levels of genes involved in cell cycle regulation, cellular senescence and telomere protection. This study points to NEIL3 as a telomere-protecting protein in murine bone marrow in vivo.
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•Deficiency of DNA repair enzyme NEIL3 leads to shortened telomeres in Apoe−/− mice.•Hematopoietic capacity is impaired in Apoe−/− mice lacking NEIL3.•Transcripts linked to telomere protection are down-regulated in Apoe−/−/Neil3−/− mice.
Endonuclease V (EndoV) is a conserved inosine-specific ribonuclease with unknown biological function. Here, we present the first mouse model lacking EndoV, which is viable without visible ...abnormalities. We show that endogenous murine EndoV cleaves inosine-containing RNA in vitro, nevertheless a series of experiments fails to link an in vivo function to processing of such transcripts. As inosine levels and adenosine-to-inosine editing often are dysregulated in hepatocellular carcinoma (HCC), we chemically induced HCC in mice. All mice developed liver cancer, however, EndoV-/- tumors were significantly fewer and smaller than wild type tumors. Opposed to human HCC, adenosine deaminase mRNA expression and site-specific editing were unaltered in our model. Loss of EndoV did not affect editing levels in liver tumors, however mRNA expression of a selection of cancer related genes were reduced. Inosines are also found in certain tRNAs and tRNAs are cleaved during stress to produce signaling entities. tRNA fragmentation was dysregulated in EndoV-/- livers and apparently, inosine-independent. We speculate that the inosine-ribonuclease activity of EndoV is disabled in vivo, but RNA binding allowed to promote stabilization of transcripts or recruitment of proteins to fine-tune gene expression. The EndoV-/- tumor suppressive phenotype calls for related studies in human HCC.
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