Monocytes are involved in adverse left ventricular (LV) remodelling following myocardial infarction (MI). To provide therapeutic opportunities we aimed to identify gene transcripts in monocytes that ...relate to post-MI healing and evaluated intervention with the observed gene activity in a rat MI model. In 51 MI patients treated by primary percutaneous coronary intervention (PCI), the change in LV end-diastolic volume index (EDVi) from baseline to 4-month follow-up was assessed using cardiovascular magnetic resonance imaging (CMR). Circulating monocytes were collected at day 5 (Arterioscler Thromb Vasc Biol 35:1066–1070,
2015
; Cell Stem Cell 16:477–487,
2015
; Curr Med Chem 13:1877–1893,
2006
) after primary PCI for transcriptome analysis. Transcriptional profiling and pathway analysis revealed that patients with a decreased LV EDVi showed an induction of type I interferon (IFN) signalling (type I IFN pathway:
P
value < 0.001; false discovery rate < 0.001). We subsequently administered 15,000 Units of IFN-α subcutaneously in a rat MI model for three consecutive days following MI. Cardiac function was measured using echocardiography and infarct size/cardiac inflammation using (immuno)-histochemical analysis. We found that IFN-α application deteriorated ventricular dilatation and increased infarct size at day 28 post-MI. Moreover, IFN-α changed the peripheral monocyte subset distribution towards the pro-inflammatory monocyte subset whereas in the myocardium, the presence of the alternative macrophage subset was increased at day 3 post-MI. Our findings suggest that induction of type I IFN signalling in human monocytes coincides with adverse LV remodelling. In rats, however, IFN-α administration deteriorated post-MI healing. These findings underscore important but also contradictory roles for the type I IFN response during cardiac healing following MI.
Background: Rheumatoid arthritis (RA) is a heterogeneous disease with unknown cause. Aim: To identify peripheral blood (PB) gene expression profiles that may distinguish RA subtypes. Methods: ...Large-scale expression profiling by cDNA microarrays was performed on PB from 35 patients and 15 healthy individuals. Differential gene expression was analysed by significance analysis of microarrays (SAM), followed by gene ontology analysis of the significant genes. Gene set enrichment analysis was applied to identify pathways relevant to disease. Results: A substantially raised expression of a spectrum of genes involved in immune defence was found in the PB of patients with RA compared with healthy individuals. SAM analysis revealed a highly significant elevated expression of interferon (IFN) type I regulated genes in patients with RA compared with healthy individuals, which was confirmed by gene ontology and pathway analysis, suggesting that this pathway was activated systemically in RA. A quantitative analysis revealed that increased expression of IFN-response genes was characteristic of approximately half of the patients (IFNhigh patients). Application of pathway analysis revealed that the IFNhigh group was largely different from the controls, with evidence for upregulated pathways involved in coagulation and complement cascades, and fatty acid metabolism, while the IFNlow group was similar to the controls. Conclusion: The IFN type I signature defines a subgroup of patients with RA, with a distinct biomolecular phenotype, characterised by increased activity of the innate defence system, coagulation and complement cascades, and fatty acid metabolism.
Blood-brain barrier (BBB) dysfunction is a major hallmark of many neurological diseases, including multiple sclerosis (MS). Using a genomics approach, we defined a microRNA signature that is ...diminished at the BBB of MS patients. In particular, miR-125a-5p is a key regulator of brain endothelial tightness and immune cell efflux. Our findings suggest that repair of a disturbed BBB through microRNAs may represent a novel avenue for effective treatment of MS.
Inflammatory immune disorders such as inflammatory bowel disease and multiple sclerosis are major health problems. Currently, the intestinal whipworm Trichuris suis is being explored in clinical ...trials to reduce inflammation in these diseases; however, the mechanisms by which the parasite affects the host immune system are not known. Here we determined the effects of T. suis soluble products (SPs) on Toll-like receptor-4 (TLR4)-stimulated human dendritic cells (DCs) using Illumina bead chip gene arrays. Pathway analysis of lipopolysaccharide-stimulated DCs with or without T. suis treatment showed that co-stimulation with T. suis SPs resulted in a downregulation of both the myeloid differentiation primary response gene 88-dependent and the TIR-domain-containing adaptor-inducing interferon-β-dependent signalling pathways triggered by TLR4. These data were verified using quantitative real-time PCR of several key genes within these pathways and/or defining their protein levels. In addition, T. suis SPs induce Rab7b, a negative regulator of TLR4 signalling that interferes with its trafficking, which coincided with a reduced surface expression of TLR4. These data indicate that the mechanism by which T. suis SPs reduce inflammatory responses is through suppression of both TLR4 signalling and surface expression on DCs.
Galectin-2 is a monocyte-expressed carbohydrate-binding lectin, for which increased expression is genetically determined and associated with decreased collateral arteriogenesis in obstructive ...coronary artery disease patients. The inhibiting effect of galectin-2 on arteriogenesis was confirmed in vivo, but the mechanism is largely unknown. In this study we aimed to explore the effects of galectin-2 on monocyte/macrophage phenotype in vitro and vivo, and to identify the receptor by which galectin-2 exerts these effects. We now show that the binding of galectin-2 to different circulating human monocyte subsets is dependent on monocyte surface expression levels of CD14. The high affinity binding is blocked by an anti-CD14 antibody but not by carbohydrates, indicating a specific protein-protein interaction. Galectin-2 binding to human monocytes modulated their transcriptome by inducing proinflammatory cytokines and inhibiting pro-arteriogenic factors, while attenuating monocyte migration. Using specific knock-out mice, we show that galectin-2 acts through the CD14/toll-like receptor (TLR)-4 pathway. Furthermore, galectin-2 skews human macrophages to a M1-like proinflammatory phenotype, characterized by a reduced motility and expression of an anti-arteriogenic cytokine/growth factor repertoire. This is accompanied by a switch in surface protein expression to CD40-high and CD206-low (M1). In a murine model we show that galectin-2 administration, known to attenuate arteriogenesis, leads to increased numbers of CD40-positive (M1) and reduced numbers of CD206-positive (M2) macrophages surrounding actively remodeling collateral arteries. In conclusion galectin-2 is the first endogenous CD14/TLR4 ligand that induces a proinflammatory, non-arteriogenic phenotype in monocytes/macrophages. Interference with CD14-Galectin-2 interaction may provide a new intervention strategy to stimulate growth of collateral arteries in genetically compromised cardiovascular patients.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
During prolonged hypoxic conditions, endothelial cells change their gene expression to adjust to the low oxygen environment. This process is mainly regulated by the hypoxia-inducible factors, HIF-1α ...and HIF-2α. Although endothelial cells do not form sprouts during prolonged hypoxic culturing, silencing of HIF-2α partially restores sprout formation. The present study identifies novel HIF-2α-target genes that may regulate endothelial sprouting during prolonged hypoxia. The gene expression profile of primary human microvascular endothelial cells (hMVECs) that were cultured at 20 % oxygen was compared to hMVECs that were cultured at 1 % oxygen for 14 days by using genome-wide RNA-sequencing. The differentially regulated genes in hypoxia were compared to the genes that were differentially regulated upon silencing of HIF-2α in hypoxia. Surprisingly, KEGG pathway analysis showed that metabolic pathways were enriched within genes upregulated in response to hypoxia and enriched within genes downregulated upon HIF-2α silencing. Moreover, 51 HIF-2α-regulated genes were screened for their role in endothelial sprouting in hypoxia, of which four genes ARRDC3, MME, PPARG and RALGPS2 directly influenced endothelial sprouting during prolonged hypoxic culturing. The manipulation of specific downstream targets of HIF-2α provides a new, but to be further evaluated, perspective for restoring reduced neovascularization in several pathological conditions, such as diabetic ulcers or other chronic wounds, for improvement of vascularization of implanted tissue-engineered scaffolds.
Background
In order to identify factors that stimulate arteriogenesis after ischemia, we followed gene expression profiles in two extreme models for collateral artery formation over 28 days after ...hindlimb ischemia, namely “good‐responding” C57BL/6 mice and “poor‐responding” BALB/c mice.
Methods and Results
Although BALB/c mice show very poor blood flow recovery after ischemia, most known proarteriogenic genes were upregulated more excessively and for a longer period than in C57BL/6 mice. In clear contrast, chemokine genes Ccl19, Ccl21a, and Ccl21c and the chemokine receptor CCR7 were upregulated in C57BL/6 mice 1 day after hindlimb ischemia, but not in BALB/C mice. CCL19 and CCL21 regulate migration and homing of T lymphocytes via CCR7. When subjecting CCR7−/−/LDLR−/− mice to hindlimb ischemia, we observed a 20% reduction in blood flow recovery compared with that in LDLR−/− mice. Equal numbers of α‐smooth muscle actin–positive collateral arteries were found in the adductor muscles of both mouse strains, but collateral diameters were smaller in the CCR7−/−/LDLR−/−. Fluorescence‐activated cell sorter analyses showed that numbers of CCR7+ T lymphocytes (both CD4+ and CD8+) were decreased in the spleen and increased in the blood at day 1 after hindlimb ischemia in LDLR−/− mice. At day 1 after hindlimb ischemia, however, numbers of activated CD4+ T lymphocytes were decreased in the draining lymph nodes of LDLR−/− mice compared with CCR7−/−/LDLR−/− mice.
Conclusions
These data show that CCR7‐CCL19/CCL21 axis facilitates retention CD4+ T lymphocytes at the site of collateral artery remodeling, which is essential for effective arteriogenesis.
Recent clinical trials in patients with inflammatory diseases like multiple sclerosis (MS) or inflammatory bowel disease (IBD) have shown the beneficial effects of probiotic helminth administration, ...although the underlying mechanism of action remains largely unknown. Potential cellular targets may include innate immune cells that propagate inflammation in these diseases, like pro-inflammatory macrophages. We here investigated the effects of the helminth Trichuris suis soluble products (SPs) on the phenotype and function of human inflammatory (granulocyte-macrophage colony-stimulating factor (GM-CSF)-differentiated) macrophages. Interestingly, we here show that T. suis SPs potently skew inflammatory macrophages into a more anti-inflammatory state in a Toll-like receptor 4 (TLR4)-dependent manner, and less effects are seen when stimulating macrophages with TLR2 or -3 ligands. Gene microarray analysis of GM-CSF-differentiated macrophages further revealed that many TLR4-induced inflammatory mediators, including interleukin (IL)-12B, CCL1 and CXCL9, are downregulated by T. suis SPs. In particular, we observed a strong reduction in the expression and function of P2RX7, a purinergic receptor involved in macrophage inflammation, leading to reduced IL-1β secretion. In conclusion, we show that T. suis SPs suppress a broad range of inflammatory pathways in GM-CSF-differentiated macrophages in a TLR4-dependent manner, thereby providing enhanced mechanistic insight into the therapeutic potential of this helminth for patients with inflammatory diseases.
Abstract Galectins are an ancient family of β-galactoside-specific lectins and consist of 15 different types, each with a specific function. They play a role in the immune system, inflammation, wound ...healing and carcinogenesis. In particular the role of galectin in cancer is widely studied. Lately, the role of galectins in the development of cardiovascular disease has gained attention. Worldwide cardiovascular disease is still the leading cause of death. In ischemic heart disease, atherosclerosis limits adequate blood flow. Angiogenesis and arteriogenesis are highly important mechanisms relieving ischemia by restoring perfusion to the post-stenotic myocardial area. Galectins act ambiguous, both relieving ischemia and accelerating atherosclerosis. Atherosclerosis can ultimately lead to myocardial infarction or ischemic stroke, which are both associated with galectins. There is also a role for galectins in the development of myocarditis by their influence on inflammatory processes. Moreover, galectin acts as a biomarker for the severity of myocardial ischemia and heart failure. This review summarizes the association between galectins and the development of multiple cardiovascular diseases such as myocarditis, ischemic stroke, myocardial infarction, heart failure and atrial fibrillation. Furthermore it focuses on the association between galectin and more general mechanisms such as angiogenesis, arteriogenesis and atherosclerosis.
Activation of the type I interferon (IFN) response program is described for several autoimmune diseases, including systemic lupus erythematosus (SLE), multiple sclerosis (MS), myositis (IIM) and ...rheumatoid arthritis (RA). While IFNα contributes to SLE pathology, IFNβ therapy is often beneficial in MS, implying different immunoregulatory roles for these IFNs. This study was aimed to investigate potential diversification of IFNα-and IFNβ-mediated response programs in autoimmune diseases.
Peripheral blood gene expression of 23 prototypical type I IFN response genes (IRGs) was determined in 54 healthy controls (HCs), 69 SLE (47 test, 22 validation), 149 IFNβ-treated MS (71 test, 78 validation), 160 untreated MS, 78 IIM and 76 RA patients. Patients with a type I IFN signature were selected for analysis.
We identified IFNα- and IFNβ-specific response programs (GC-A and GC-B, respectively) in SLE and IFNβ-treated MS patients. Concordantly, the GC-A/GC-B log-ratio was positive for all SLE patients and negative for virtually all IFNβ-treated MS patients, which was confirmed in additional cohorts. Applying this information to other autoimmune diseases, IIM patients displayed positive GC-A/GC-B log-ratios, indicating predominant IFNα activity. The GC-A/GC-B log-ratio in RA was lower and approached zero in part of the patients, implying relative importance of both clusters. Remarkably, GC-A/GC-B log-ratios appeared most heterogeneous in untreated MS; half of the patients displayed GC-A dominance, whereas others showed GC-B dominance or log-ratios near zero.
Our findings show diversification of the type I IFN response in autoimmune diseases, suggesting different pathogenic roles of the type I IFNs.
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