Publications
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Udjus, Camilla; Halvorsen, Bente; Kong, Xiang Yi; Sagen, Ellen Lund; Martinsen, Marita & Yang, Kuan
[Show all 10 contributors for this article]
(2024).
Alveolar hypoxia induces organ-specific inflammasome-related inflammation in male mouse lungs.
Physiological Reports.
12:e16143(14),
p. 1–13.
doi:
10.14814/phy2.16143.
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Inflammation through activation of caspase-1, seems to play a role in pulmonary hypertension induced by alveolar hypoxia. Whether alveolar hypoxia induces caspase-1-mediated inflammation and influx of leukocytes in other organs than the lungs, is not known. Our aim was to explore sites of caspase-1-related inflammation in alveolar hypoxia. Wild type (WT) mice were exposed to environmental hypoxia or room-air, and organs were analyzed. Right heart catheterization was performed after 14 days of alveolar hypoxia in WT mice and mice transplanted with WT or caspase-1−/− bone marrow. Hypoxia induced leukocyte accumulation and increased caspase-1 protein in the lungs, not in other organs. WT mice transplanted with WT or caspase-1−/− bone marrow showed no difference in pulmonary leukocyte accumulation or development of pulmonary hypertension after alveolar hypoxia. Caspase-1 and IL-18 were detected in bronchial epithelium in WT mice, and hypoxia induced IL-18 secretion from bronchial epithelial cells. IL-18 stimulation generated IL-6 mRNA in monocytes. Phosphorylated STAT3 was increased in hypoxic lungs, not in other organs. Alveolar hypoxia induces caspase-1 activation and leukocyte accumulation specific to the lungs, not in other organs. Caspase-1 activation and IL-18 secretion from bronchial epithelial cells might initiate hypoxia-induced inflammation, leading to pulmonary hypertension.
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Olsen, Maria Belland; Kong, Xiang Yi; Louwe, Maria; Lauritzen, Knut Husø; Schanke, Ylva & Kaasbøll, Ole Jørgen
[Show all 14 contributors for this article]
(2024).
SLAMF1-derived peptide exhibits cardio protection after permanent left anterior descending artery ligation in mice.
Frontiers in Immunology.
15.
doi:
10.3389/fimmu.2024.1383505.
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Acute myocardial infarction (MI) results in tissue damage to affected areas of the myocardium. The initial inflammatory response is the most damaging for residual cardiac function, while at later stages inflammation is a prerequisite for proper healing and scar formation. Balancing the extent and duration of inflammation during various stages after MI is thus pivotal for preserving cardiac function. Recently, a signaling lymphocytic activation molecule 1 (SLAMF1)-derived peptide (P7) was shown to reduce the secretion of inflammatory cytokines and protected against acute lipopolysaccharide-induced death in mice. In the present study, we experimentally induced MI by permanent ligation of the left anterior descending artery (LAD) in mice and explored the beneficial effect of immediately administering P7, with the aim of dampening the initial inflammatory phase without compromising the healing and remodeling phase. Blood samples taken 9 h post-LAD surgery and P7 administration dampened the secretion of inflammatory cytokines, but this dampening effect of P7 was diminished after 3 days. Echocardiography revealed less deterioration of cardiac contraction in mice receiving P7. In line with this, less myocardial damage was observed histologically in P7-treated mice. In conclusion, the administration of a SLAMF1-derived peptide (P7) immediately after induction of MI reduces the initial myocardial inflammation, reduces infarct expansion, and leads to less deterioration of cardiac contraction.
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Holme, Fredric André; Huse, Camilla; Kong, Xiang Yi; Broch, Kaspar; Gullestad, Lars & Anstensrud, Anne Kristine
[Show all 15 contributors for this article]
(2024).
Circular RNA Profile in Atherosclerotic Disease: Regulation during ST-Elevated Myocardial Infarction.
International Journal of Molecular Sciences.
ISSN 1661-6596.
25(16),
p. 1–15.
doi:
10.3390/ijms25169014.
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Circular (circ) RNAs are non-coding RNAs with important functions in the nervous system, cardiovascular system, and cancer. Their role in atherosclerosis and myocardial infarction (MI) remains poorly described. We aim to investigate the potential circRNAs in immune cells during atherogenesis and examine the most regulated during MI and the modulation by interleukin (IL)-6 receptor inhibition by tocilizumab. Wild-type (WT) and ApoE−/− mice were fed an atherogenic diet for 10 weeks, and the circRNA profile was analyzed by circRNA microarray. Whole blood from patients with ST-elevated MI (STEMI) and randomized to tocilizumab (n = 21) or placebo (n = 19) was collected at admission, 3–7 days, and at 6 months, in addition to samples from healthy controls (n = 13). Primers for human circRNA were designed, and circRNA levels were measured using RT-qPCR. mRNA regulation of predicted circRNA targets was investigated by RNA sequencing. The expression of 867 circRNAs differed between atherogenic and WT mice. In STEMI patients, circUBAC2 was significantly lower than in healthy controls. CircANKRD42 and circUBAC2 levels were inversely correlated with troponin T, and for circUBAC2, an inverse correlation was also seen with final infarct size at 6 months. The predicted mRNA targets for circUBAC2 and circANKRD42 were investigated and altered levels of transcripts involved in the regulation of inflammatory/immune cells, apoptosis, and mitochondrial function were found. Finally, tocilizumab induced an up-regulation of circANKRD42 and circUBAC2 3–7 days after percutaneous coronary intervention. CircRNA levels were dysregulated in STEMI, potentially influencing the immune system, apoptosis, and mitochondrial function.
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Gregersen, Ida; Kong, Xiang Yi; Kooijman, Sander; Foyn, Håvard; Grannes, Helene & Olsen, Maria Belland
[Show all 25 contributors for this article]
(2024).
T cells with increased responsiveness cause obesity in mice without diet intervention.
iScience.
27(4).
doi:
10.1016/j.isci.2024.109471.
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Obesity is a complex multicausal disease that can cause morbidity and mortality, and there is need for improved knowledge on the underlying mechanisms. Using a mouse model of increased T cell responsiveness, we show that development of obesity can be driven by immune cells. This was confirmed with bone marrow transplantation and adoptive T cell transfer to several recipient mouse models. Single-cell RNA sequencing and CyTOF analysis showed that the mice display altered composition of circulating T cells and increased T cell activation in visceral adipose tissue, suggesting activated T cells as critical players in the increased fat mass. In this study, we provide evidence that obesity can be driven by immune cell activity and in particular by T cells, which could have broad implications for prevention and treatment of this condition.
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Karlsen, Tom Rune; Olsen, Maria Belland; Kong, Xiang Yi; Yang, Kuan; Quiles-Jiménez, Ana M T & Kroustallaki, Pinelopi
[Show all 15 contributors for this article]
(2022).
NEIL3-deficient bone marrow displays decreased hematopoietic capacity and reduced telomere length.
Biochemistry and Biophysics Reports.
29.
doi:
10.1016/j.bbrep.2022.101211.
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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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Kong, Xiang Yi; Huse, Camilla; Yang, Kuan; Øgaard, Jonas; Jimenez, Natalia Berges & Vik, Erik Sebastian
[Show all 24 contributors for this article]
(2021).
Endonuclease v regulates atherosclerosis through c-c motif chemokine ligand 2-mediated monocyte infiltration.
Journal of the American Heart Association (JAHA).
10(14).
doi:
10.1161/JAHA.120.020656.
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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.
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Cokan, Kaja Blagotinšek; Urlep, Žiga; Moškon, Miha; Mraz, Miha; Kong, Xiang Yi & Eskild, Winnie
[Show all 9 contributors for this article]
(2021).
Common Transcriptional Program of Liver Fibrosis in Mouse Genetic Models and Humans.
International Journal of Molecular Sciences.
ISSN 1661-6596.
22(2),
p. 1–21.
doi:
10.3390/ijms22020832.
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Multifactorial metabolic diseases, such as non-alcoholic fatty liver disease, are a major burden to modern societies, and frequently present with no clearly defined molecular biomarkers. Herein we used system medicine approaches to decipher signatures of liver fibrosis in mouse models with malfunction in genes from unrelated biological pathways: cholesterol synthesis—Cyp51, notch signaling—Rbpj, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling—Ikbkg, and unknown lysosomal pathway—Glmp. Enrichment analyses of Kyoto Encyclopedia of Genes and Genomes (KEGG), Reactome and TRANScription FACtor (TRANSFAC) databases complemented with genome-scale metabolic modeling revealed fibrotic signatures highly similar to liver pathologies in humans. The diverse genetic models of liver fibrosis exposed a common transcriptional program with activated estrogen receptor alpha (ERα) signaling, and a network of interactions between regulators of lipid metabolism and transcription factors from cancer pathways and the immune system. The novel hallmarks of fibrosis are downregulated lipid pathways, including fatty acid, bile acid, and steroid hormone metabolism. Moreover, distinct metabolic subtypes of liver fibrosis were proposed, supported by unique enrichment of transcription factors based on the type of insult, disease stage, or potentially, also sex. The discovered novel features of multifactorial liver fibrotic pathologies could aid also in improved stratification of other fibrosis related pathologies.
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Karlsen, Tom Rune; Kong, Xiang Yi; Holm, Sverre; Quiles-Jiménez, Ana M T; Dahl, Tuva Børresdatter & Yang, Kuan
[Show all 17 contributors for this article]
(2021).
NEIL3-deficiency increases gut permeability and contributes to a pro-atherogenic metabolic phenotype.
Scientific Reports.
11(1).
doi:
10.1038/s41598-021-98820-0.
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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.
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Quiles-Jiménez, Ana M T; Gregersen, Ida; Segers, Filip; Skarpengland, Tonje; Kroustallaki, Pinelopi & Yang, Kuan
[Show all 30 contributors for this article]
(2021).
DNA glycosylase Neil3 regulates vascular smooth muscle cell biology during atherosclerosis development.
Atherosclerosis.
ISSN 0021-9150.
324,
p. 123–132.
doi:
10.1016/j.atherosclerosis.2021.02.023.
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Background and aims 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. Methods 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. Results 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. Conclusions 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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Holm, Sverre; Kared, Hassen; Michelsen, Annika Elisabet; Kong, Xiang Yi; Dahl, Tuva Børresdatter & Schultz, Nina Haagenrud
[Show all 21 contributors for this article]
(2021).
Immune complexes, innate immunity, and NETosis in ChAdOx1 vaccine-induced thrombocytopenia.
European Heart Journal.
ISSN 0195-668X.
42(39),
p. 4064–4072.
doi:
10.1093/eurheartj/ehab506.
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Aims - We recently reported five cases of vaccine-induced immune thrombotic thrombocytopenia (VITT) 7–10 days after receiving the first dose of the ChAdOx1 nCoV-19 adenoviral vector vaccine against corona virus disease 2019 (COVID-19). We aimed to investigate the pathogenic immunological responses operating in these patients.<p> <p>Methods and results - We assessed circulating inflammatory markers by immune assays and immune cell phenotyping by flow cytometry analyses and performed immunoprecipitation with anti-platelet factor (PF)4 antibody in plasma samples followed by mass spectrometry from all five patients. A thrombus was retrieved from the sinus sagittal superior of one patient and analysed by immunohistochemistry and flow cytometry. Precipitated immune complexes revealed multiple innate immune pathway triggers for platelet and leucocyte activation. Plasma contained increased levels of innate immune response cytokines and markers of systemic inflammation, extensive degranulation of neutrophils, and tissue and endothelial damage. Blood analyses showed activation of neutrophils and increased levels of circulating H3Cit, dsDNA, and myeloperoxidase–DNA complex. The thrombus had extensive infiltration of neutrophils, formation of neutrophil extracellular traps (NETs), and IgG deposits.<p> <p>Conclusions - The results show that anti-PF4/polyanion IgG-mediated thrombus formation in VITT patients is accompanied by a massive innate immune activation and particularly the fulminant activation of neutrophils including NETosis. These results provide novel data on the immune response in this rare adenoviral vector-induced VITT.
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Lambert, Anna Tancin; Kong, Xiang Yi; Ratajczak-Tretel, Barbara; Atar, Dan; Russell, David & Skjelland, Mona Elisabet
[Show all 13 contributors for this article]
(2020).
Biomarkers Associated with Atrial Fibrillation in Patients with Ischemic Stroke: A Pilot Study from the NOR-FIB Study.
Cerebrovascular Diseases Extra.
ISSN 1664-5456.
10(1),
p. 11–20.
doi:
10.1159/000504529.
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Background and Purpose: Cardioembolic stroke due to paroxysmal atrial fibrillation (AF) may account for 1 out of 4 cryptogenic strokes (CS) and transient ischemic attacks (TIAs). The purpose of this pilot study was to search for biomarkers potentially predicting incident AF in patients with ischemic stroke or TIA. Methods: Plasma samples were collected from patients aged 18 years and older with ischemic stroke or TIA due to AF (n = 9) and large artery atherosclerosis (LAA) with ipsilateral carotid stenosis (n = 8) and age- and sex-matched controls (n = 10). Analyses were performed with the Olink technology simultaneously measuring 184 biomarkers of cardiovascular disease. For bioinformatics, acquired data were analyzed using gene set enrichment analysis (GSEA). Selected proteins were validated using ELISA. Individual receiver operating characteristic (ROC) curves and odds ratios from logistic regression were calculated. A randomForest (RF) model with out-of-bag estimate was applied for predictive modeling. Results: GSEA indicated enrichment of proteins related to inflammatory response in the AF group. Interleukin (IL)-6, growth differentiation factor (GDF)-15, and pentraxin-related protein PTX3 were the top biomarkers on the ranked list for the AF group compared to the LAA group and the control group. ELISA validated increased expression of all tested proteins (GDF-15, PTX3, and urokinase plasminogen activator surface receptor [U-PAR]), except for IL-6. 19 proteins had the area under the ROC curve (AUC) over 0.85 including all of the proteins with significant evolution in the logistic regression. AUCs were very discriminant in distinguishing patients with and without AF (LAA and control group together). GDF-15 alone reached AUC of 0.95. Based on RF model, all selected participants in the tested group were classified correctly, and the most important protein in the model was GDF-15. Conclusions: Our results demonstrate an association between inflammation and AF and that multiple proteins alone and in combination may potentially be used as indicators of AF in CS and TIA patients. However, further studies including larger samples sizes are needed to support these findings. In the ongoing NOR-FIB study, we plan further biomarker assessments in patients with CS and TIA undergoing long-term cardiac rhythm monitoring with insertable cardiac monitors.
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Kong, Xiang Yi; Vik, Erik Sebastian; Nawaz, Meh Sameen; Berges, Natalia; Dahl, Tuva Børresdatter & Vågbø, Cathrine
[Show all 17 contributors for this article]
(2020).
Deletion of Endonuclease V suppresses chemically induced hepatocellular carcinoma.
Nucleic Acids Research (NAR).
ISSN 0305-1048.
48(8),
p. 4463–4479.
doi:
10.1093/nar/gkaa115.
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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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Niyonzima, Nathalie; Bakke, Siril Skaret; Gregersen, Ida; Holm, Sverre; Sandanger, Øystein & Orrem, Hilde Lang
[Show all 22 contributors for this article]
(2020).
Cholesterol crystals use complement to increase NLRP3 signaling pathways in coronary and carotid atherosclerosis.
EBioMedicine.
60:102985,
p. 1–13.
doi:
10.1016/j.ebiom.2020.102985.
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Background: During atherogenesis, cholesterol precipitates into cholesterol crystals (CC) in the vessel wall, which trigger plaque inflammation by activating the NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome. We investigated the relationship between CC, complement and NLRP3 in patients with cardiovascular disease. Methods: We analysed plasma, peripheral blood mononuclear cells (PBMC) and carotid plaques from patients with advanced atherosclerosis applying ELISAs, multiplex cytokine assay, qPCR, immunohistochemistry, and gene profiling. Findings: Transcripts of interleukin (IL)-1beta(b) and NLRP3 were increased and correlated in PBMC from patients with acute coronary syndrome (ACS). Priming of these cells with complement factor 5a (C5a) and tumour necrosis factor (TNF) before incubation with CC resulted in increased IL-1b protein when compared to healthy controls. As opposed to healthy controls, systemic complement was significantly increased in patients with stable angina pectoris or ACS. In carotid plaques, complement C1q and C5b-9 complex accumulated around CC-clefts, and complement receptors C5aR1, C5aR2 and C3aR1 were higher in carotid plaques compared to control arteries. Priming human carotid plaques with C5a followed by CC incubation resulted in pronounced release of IL-1b, IL-18 and IL-1a. Additionally, mRNA profiling demonstrated that C5a and TNF priming followed by CC incubation upregulated plaque expression of NLRP3 inflammasome components. Interpretation: We demonstrate that CC are important local- and systemic complement activators, and we reveal that the interaction between CC and complement could exert its effect by activating the NLRP3 inflammasome, thus promoting the progression of atherosclerosis.
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Jimenez, Ana Maria Teresa Quiles; Gregersen, Ida; Sousa, Mirta; Abbas, Azhar; Kong, Xiang Yi & Alseth, Ingrun
[Show all 13 contributors for this article]
(2020).
N6-methyladenosine in RNA of atherosclerotic plaques: An epitranscriptomic signature of human carotid atherosclerosis.
Biochemical and Biophysical Research Communications - BBRC.
ISSN 0006-291X.
533(4),
p. 631–637.
doi:
10.1016/j.bbrc.2020.09.057.
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Background 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. Methods 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. Findings (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. Interpretation 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.
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Lunde, Ngoc Dieu Nguyen; Gregersen, Ida; Ueland, Thor; Shetelig, Christian; Holm, Sverre & Kong, Xiang Yi
[Show all 31 contributors for this article]
(2019).
Legumain is upregulated in acute cardiovascular events and associated with improved outcome – potentially related to anti-inflammatory effects on macrophages.
Atherosclerosis.
ISSN 0021-9150.
p. 1–9.
doi:
10.1016/j.atherosclerosis.2019.12.008.
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Background and aims We have previously found increased levels of the cysteine protease legumain in plasma and plaques from patients with carotid atherosclerosis. This study further investigated legumain during acute cardiovascular events. Methods Circulating levels of legumain from patients and legumain released from platelets were assessed by enzyme-linked-immunosorbent assay. Quantitative PCR and immunoblotting were used to study expression, while localization was visualized by immunohistochemistry. Results In the SUMMIT Malmö cohort (n = 339 with or without type 2 diabetes and/or cardiovascular disease [CVD], and 64 healthy controls), the levels of circulating legumain were associated with the presence of CVD in non-diabetics, with no relation to outcome. In symptomatic carotid plaques and in samples from both coronary and intracerebral thrombi obtained during acute cardiovascular events, legumain was co-localized with macrophages in the same regions as platelets. In vitro, legumain was shown to be present in and released from platelets upon activation. In addition, THP-1 macrophages exposed to releasate from activated platelets showed increased legumain expression. Interestingly, primary peripheral blood mononuclear cells stimulated with recombinant legumain promoted anti-inflammatory responses. Finally, in a STEMI population (POSTEMI; n = 272), patients had significantly higher circulating legumain before and immediately after percutaneous coronary intervention compared with healthy controls (n = 67), and high levels were associated with improved outcome. Conclusions Our data demonstrate for the first time that legumain is upregulated during acute cardiovascular events and is associated with improved outcome.
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Macpherson, Magnhild Eide; Halvorsen, Bente; Yndestad, Arne; Ueland, Thor; Mollnes, Tom Eirik & Berge, Rolf Kristian
[Show all 14 contributors for this article]
(2019).
Impaired HDL function amplifies systemic inflammation in common variable immunodeficiency.
Scientific Reports.
9:9427,
p. 1–10.
doi:
10.1038/s41598-019-45861-1.
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Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency, characterized by inadequate antibody responses and recurrent bacterial infections. Paradoxically, a majority of CVID patients have non-infectious inflammatory and autoimmune complications, associated with systemic immune activation. Our aim was to explore if HDL, known to have anti-inflammatory properties, had impaired function in CVID patients and thereby contributed to their inflammatory phenotype. We found reduced HDL cholesterol levels in plasma of CVID patients compared to healthy controls, particularly in patients with inflammatory and autoimmune complications, correlating negatively with inflammatory markers CRP and sCD25. Reverse cholesterol transport capacity testing showed reduced serum acceptance capacity for cholesterol in CVID patients with inflammatory and autoimmune complications. They also had reduced cholesterol efflux capacity from macrophages to serum and decreased expression of ATP-binding cassette transporter ABCA1. Human HDL suppressed TLR2-induced TNF release less in blood mononuclear cells from CVID patients, associated with decreased expression of transcriptional factor ATF3. Our data suggest a link between impaired HDL function and systemic inflammation in CVID patients, particularly in those with autoimmune and inflammatory complications. This identifies HDL as a novel therapeutic target in CVID as well as other more common conditions characterized by sterile inflammation or autoimmunity.
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Schistad, Ellina Iordanova; Kong, Xiang Yi; Furberg, Anne-Sofie; Bäckryd, Emmanuel; Grimnes, Guri & Emaus, Nina
[Show all 12 contributors for this article]
(2019).
A population-based study of inflammatory mechanisms and pain sensitivity.
Pain.
ISSN 0304-3959.
161(2),
p. 338–350.
doi:
10.1097/j.pain.0000000000001731.
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Two recent studies suggest that experimental pain sensitivity is associated with low-grade systemic inflammation. However, only 2 biomarkers have been identified, and the studies were conducted in adult individuals where confounding effects of comorbid diseases cannot be excluded. We therefore tested associations between pain sensitivity and 119 inflammation-related serum biomarkers in 827 healthy adolescents (15-19 years) in the population-based Tromsø Study: Fit Futures. The main outcome measure was cold-pressor pain tolerance (CPT), tested by placing the dominant hand in circulating cold (3°C) water for a maximum of 105 seconds. Secondary outcomes were heat and pressure pain threshold and tolerance. Twelve proteins and 6 fatty acids were significantly associated with CPT after adjustment for possible confounding factors and correction for multiple comparisons. Of these, all fatty acids and 10 proteins were protective, ie, higher biomarkers levels were associated with increased CPT, whereas 2 biomarkers were associated with lower tolerance. Taken together, these biomarkers predicted completion of the tolerance test with a C-statistic of 0.65. Results for heat and pressure pain tolerance were remarkably similar, strengthening the generalizability of our findings. In this cohort of young healthy individuals, we found a relationship between inflammation-related biomarkers and pain tolerance and thresholds. Biomarkers with anti-inflammatory and analgesic effects predominated, suggesting that the development of prophylactic dietary or pharmaceutical treatments may be possible.
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Skarpengland, Tonje; Skjelland, Mona; Kong, Xiang Yi; Skagen, Karolina Ryeng; Holm, Sverre & Otterdal, Kari
[Show all 16 contributors for this article]
(2018).
Increased levels of lectin-like oxidized low-density lipoprotein receptor-1 in ischemic stroke and transient ischemic attack.
Journal of the American Heart Association (JAHA).
7:e006479(2),
p. 1–16.
doi:
10.1161/JAHA.117.006479.
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Background: Soluble lectin‐like oxidized low‐density lipoprotein receptor‐1 (sLOX‐1) has been shown to be increased in patients with acute ischemic stroke. Here, we evaluated plasma sLOX‐1 levels and vascular carotid plaque LOX‐1 (ie, OLR1) gene expression in patients with ischemic stroke and transient ischemic attack (TIA) with particular focus on their relation to time since symptom onset. Methods and Results: Plasma sLOX‐1 (n=232) and carotid plaque OLR1 gene expression (n=146) were evaluated in patients who were referred to evaluation for carotid endarterectomy, as well as in healthy control plasma (n=81). Patients were categorized according to presence of acute ischemic stroke or transient ischemic attack (n=35) ≤7 days, >7 days ≤3 months (n=90), >3 months (n=40), or no reported symptoms before study inclusion (n=67). Our major findings were the following: (1) Patients with carotid atherosclerosis had increased plasma sLOX‐1 levels as compared with controls. (2) Plaque OLR1 mRNA levels were increased in carotid plaques (n=146) compared with nonatherosclerotic vessels (ie, common iliac arteries of organ donors, n=10). (3) There were no differences in sLOX plasma levels or OLR1 gene expression when analyzed according to the time since relevant cerebral ischemic symptoms. (4) Also patients with severe carotid atherosclerosis without any previous ischemic events had raised sLOX‐1 levels. (5) Immunostaining showed colocalization between LOX‐1 and macrophages within the carotid plaques. (6) Also patients with acute stroke (within 7 days) caused by atrial fibrillation (n=22) had comparable raised sLOX‐1 levels. Conclusions: sLOX‐1 levels are elevated in patients with ischemic stroke and transient ischemic attack independent of cause and time since the ischemic event.
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Norum, Hilde Margrethe; Michelsen, Annika; Lekva, Tove; Arora, Satish; Otterdal, Kari & Olsen, Maria Belland
[Show all 15 contributors for this article]
(2018).
Circulating delta-like Notch ligand 1 is correlated with cardiac allograft vasculopathy and suppressed in heart transplant recipients on everolimus-based immunosuppression.
American Journal of Transplantation.
ISSN 1600-6135.
p. 1–11.
doi:
10.1111/ajt.15141.
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Cardiac allograft vasculopathy (CAV) causes heart failure after heart transplantation (HTx), but its pathogenesis is incompletely understood. Notch signaling, possibly modulated by everolimus (EVR), is essential for processes involved in CAV. We hypothesized that circulating Notch ligands would be dysregulated after HTx. We studied circulating delta‐like Notch ligand 1 (DLL1) and periostin (POSTN) and CAV in de novo HTx recipients (n = 70) randomized to standard or EVR‐based, calcineurin inhibitor‐free immunosuppression and in maintenance HTx recipients (n = 41). Compared to healthy controls, plasma DLL1 and POSTN were elevated in de novo (P < .01; P < .001) and maintenance HTx recipients (P < .001; P < .01). Use of EVR was associated with a treatment effect for DLL1. For de novo HTx recipients, a change in DLL1 correlated with a change in CAV at 1 (P = .021) and 3 years (P = .005). In vitro, activation of T cells increased DLL1 secretion, attenuated by EVR. In vitro data suggest that also endothelial cells and vascular smooth muscle cells (VSMCs) could contribute to circulating DLL1. Immunostaining of myocardial specimens showed colocalization of DLL1 with T cells, endothelial cells, and VSMCs. Our findings suggest a role of DLL1 in CAV progression, and that the beneficial effect of EVR on CAV could reflect a suppressive effect on DLL1.
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Nesset, Cecilie Kåsi; Kong, Xiang Yi; Damme, Markus; Schjalm, Camilla; Roos, Norbert & Løberg, Else Marit
[Show all 7 contributors for this article]
(2016).
Age-dependent development of liver fibrosis in Glmp (gt/gt) mice.
Fibrogenesis & Tissue Repair.
9(5).
doi:
10.1186/s13069-016-0042-4.
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Background Mice lacking glycosylated lysosomal membrane protein (Glmp gt/gt mice) have liver fibrosis as the predominant phenotype due to chronic liver injury. The Glmp gt/gt mice grow and reproduce at the same rate as their wild-type siblings. Life expectancy is around 18 months. Methods Wild-type and Glmp gt/gt mice were studied between 1 week and 18 months of age. Livers were analyzed using histological, immunohistochemical, biochemical, and qPCR analyses. Results It was shown that Glmp gt/gt mice were not born with liver injury; however, it appeared shortly after birth as indicated by excess collagen expression, deposition of fibrous collagen in the periportal areas, and increased levels of hydroxyproline in Glmp gt/gt liver. Liver functional tests indicated a chronic, mild liver injury. Markers of inflammation, fibrosis, apoptosis, and modulation of extracellular matrix increased from an early age, peaking around 4 months of age and followed by attenuation of these signals. To compensate for loss of hepatocytes, the oval cell compartment was activated, with the highest activity of the oval cells detected at 3 months of age, suggesting insufficient hepatocyte proliferation in Glmp gt/gt mice around this age. Although constant proliferation of hepatocytes and oval cells maintained adequate hepatic function in Glmp gt/gt mice, it also resulted in a higher frequency of liver tumors in older animals. Conclusions The Glmp gt/gt mouse is proposed as a model for slowly progressing liver fibrosis and possibly as a model for a yet undescribed human lysosomal disorder.
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Kong, Xiang Yi; Kase, Eili Tranheim; Herskedal, Anette; Schjalm, Camilla; Damme, Markus & Nesset, Cecilie Kåsi
[Show all 9 contributors for this article]
(2015).
Lack of the lysosomal membrane protein, GLMP, in mice results in metabolic dysregulation in liver.
PLOS ONE.
10(6).
doi:
10.1371/journal.pone.0129402.
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Ablation of glycosylated lysosomal membrane protein (GLMP, formerly known as NCU-G1) has been shown to cause chronic liver injury which progresses into liver fibrosis in mice. Both lysosomal dysfunction and chronic liver injury can cause metabolic dysregulation. Glmpgt/gt mice (formerly known as Ncu-g1gt/gtmice) were studied between 3 weeks and 9 months of age. Body weight gain and feed efficiency of Glmpgt/gt mice were comparable to wild type siblings, only at the age of 9 months the Glmpgt/gt siblings had significantly reduced body weight. Reduced size of epididymal fat pads was accompanied by hepatosplenomegaly in Glmpgt/gt mice. Blood analysis revealed reduced levels of blood glucose, circulating triacylglycerol and non-esterified fatty acids in Glmpgt/gt mice. Increased flux of glucose, increased de novo lipogenesis and lipid accumulation were detected in Glmpgt/gt primary hepatocytes, as well as elevated triacylglycerol levels in Glmpgt/gt liver homogenates, compared to hepatocytes and liver from wild type mice. Gene expression analysis showed an increased expression of genes involved in fatty acid uptake and lipogenesis in Glmpgt/gt liver compared to wild type. Our findings are in agreement with the metabolic alterations observed in other mouse models lacking lysosomal proteins, and with alterations characteristic for advanced chronic liver injury.
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Kong, Xiang Yi; Nesset, Cecilie Kåsi; Damme, Markus; Løberg, Else Marit; Lübke, Torben & Mæhlen, Jan
[Show all 13 contributors for this article]
(2014).
Loss of lysosomal membrane protein NCU-G1 in mice results in spontaneous liver fibrosis with accumulation of lipofuscin and iron in Kupffer cells.
Disease Models and Mechanisms.
ISSN 1754-8403.
7(3),
p. 351–362.
doi:
10.1242/dmm.014050.
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Human kidney predominant protein, NCU-G1, is a highly conserved protein with an unknown biological function. Initially described as a nuclear protein, it was later shown to be a bona fide lysosomal integral membrane protein. To gain insight into the physiological function of NCU-G1, mice with no detectable expression of this gene were created using a gene-trap strategy, and Ncu-g1gt/gt mice were successfully characterized. Lysosomal disorders are mainly caused by lack of or malfunctioning of proteins in the endosomal-lysosomal pathway. The clinical symptoms vary, but often include liver dysfunction. Persistent liver damage activates fibrogenesis and, if unremedied, eventually leads to liver fibrosis/cirrhosis and death. We demonstrate that the disruption of Ncu-g1 results in spontaneous liver fibrosis in mice as the predominant phenotype. Evidence for an increased rate of hepatic cell death, oxidative stress and active fibrogenesis were detected in Ncu-g1gt/gt liver. In addition to collagen deposition, microscopic examination of liver sections revealed accumulation of autofluorescent lipofuscin and iron in Ncu-g1gt/gt Kupffer cells. Because only a few transgenic mouse models have been identified with chronic liver injury and spontaneous liver fibrosis development, we propose that the Ncu-g1gt/gt mouse could be a valuable new tool in the development of novel treatments for the attenuation of fibrosis due to chronic liver damage.
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Kong, Xiang Yi; Kissen, Ralph & Bones, Atle M.
(2012).
Characterization of recombinant nitrile-specifier proteins (NSPs) of Arabidopsis thaliana: Dependency on Fe(II) ions and the effect of glucosinolate substrate and reaction conditions.
Phytochemistry.
ISSN 0031-9422.
84,
p. 7–17.
doi:
10.1016/j.phytochem.2012.08.004.
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Glucosinolates are plant secondary metabolites that are part of a plant defence system against pathogens and pests, the myrosinase-glucosinolate system, in which glucosinolates get activated by enzymic degradation through thioglucoside glucohydrolases called myrosinases. Epithiospecifier protein (ESP) and nitrile-specifier proteins (NSPs) divert myrosinase-catalysed hydrolysis of a given glucosinolate from the formation of isothiocyanate to that of epithionitrile and/or nitrile. As the biological activity of glucosinolate hydrolysis products varies considerably, a detailed characterization of these specifier proteins is of utmost importance to understand their biological role. Therefore, the Arabidopsis thaliana AtNSP1, AtNSP2 and AtNSP5 and a supposed ancestor protein AtNSP-like1 were expressed in Escherichia coli and the activity of the purified recombinant proteins was tested in vitro on three highly different glucosinolates and compared to that of purified AtESP. As previously reported, only AtESP showed epithiospecifier activity on 2-propenylglucosinolate. We further confirmed that purified AtNSP1, AtNSP2 and AtNSP5, but not the ancestor AtNSP-like1 protein, show nitrile-specifier activity on 2-propenylglucosinolate and benzylglucosinolate. We now show for the first time that in vitro AtNSP1, AtNSP2 and AtNSP5 are able to generate nitrile from indol-3-ylmethylglucosinolate. . We also tested the effect of different Fe(II) ion concentrations on the nitrile-specifier activity of purified AtNSP1, AtNSP2 and AtNSP5 on 2-propenylglucosinolate and benzylglucosinolate. AtNSP-related nitrile production was highly dependent on the presence of Fe(II) ions in the reaction assay. In the absence of added (Fe(II) ions nitriles were only detected when benzylglucosinolate was incubated with AtNSP1. While AtNSP1 also exhibited overall higher nitrile-specifier activity than AtNSP2 and AtNSP5 at a given Fe(II) ion concentration, the pattern of nitrile formation in relation to Fe(II) ion concentrations depended on the AtNSP and the glucosinolate substrate. The pH of the solution also affected the reaction outcome, with a higher proportion of nitrile being produced at the higher pH for AtNSP2 and AtNSP5.
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Published
Nov. 4, 2010 2:42 PM
- Last modified
Mar. 24, 2011 12:55 PM
