The role of interferon-regulated genes in the immune system

Type I interferons (IFNs) are potent inducers of the first-line defense against pathogens. Their activity leads to the up- and downregulation of a large number of genes with various effects on the immune system, including direct effects on the pathogens. Due to the strong response evoked by IFN signaling, the IFN pathway is tightly regulated by IFN stimulated genes to avoid detrimental effects of long-term exposure. If the IFN signaling pathway is not regulated properly, or for other reasons constantly activated, it can lead to interferonopathies and autoimmune diseases such as systemic lupus erythematosus (SLE) and Sjögren’s syndrome (SS). Indeed, many therapeutics targeting the IFN pathway are currently in clinical trials. In contrast, type I IFNs are used to treat certain types of cancer, virus infections and multiple sclerosis. The complex role of type I IFN signaling in disease is not well understood and need further characterization for better therapeutic inventions. The aim of this thesis was to identify genes that are regulated by type I IFNs and investigate their role in the immune system. To do this, we quantified the expression of interferon-regulated genes in sorted immune cells from patients with primary SS, and from individuals treated with IFN b. Using global gene expression analysis on PBMCs as well as qPCR on sorted cells, we could identify several genes that were differentially regulated by type I IFNs in different immune cell populations. Among them were TRIM21 that was upregulated in T cells and B cells, BAFF that was upregulated in T cells, monocytes and neutrophils and miR-150-5p that was selectively downregulated in monocytes. The downregulated expression of miR-150-5p consequently led to an increased expression of its target c-Myb. In addition, monocytes from patients with SLE displayed an increase in c-Myb target genes. When investigating the regulation of BAFF and TRIM21, we found that both were regulated by members of the interferon regulatory factor (IRF) family. Specifically, both were upregulated by IRF1 and IRF2, and downregulated by IRF4 and IRF8. To further investigate the role of TRIM21 in the immune system, we generated Trim21-/- mice. These mice were prone to granulocyte infiltrations and developed symptoms of autoimmune disease after being triggered by metal ear tags. We found that TRIM21 negatively regulates the immune response by ubiquitinating IRFs, and that naïve Trim21-/- mice control the development of eosinophils in the bone marrow

Contrast-enhanced magnetomotive ultrasound imaging (CE-MMUS) for colorectal cancer staging : assessment of sensitivity and resolution to detect alterations in tissue stiffness

A key challenge in the treatment of colorectal cancer is identification of the sentinel draining lymph node. Magnetomotive ultrasound, MMUS, has identified lymph nodes in rat models: superparamagnetic iron oxide nanoparticles (SPIONs) accumulated in the lymph are forced to oscillate by an external magnetic field; the resulting axial displacement is recovered allowing structure delineation with potential to indicate alterations in tissue stiffness, but it is limited by small vibration amplitudes. We propose CE-MMUS using SPION loaded microbubbles (SPION-MBs) to enhance sensitivity, reduce toxicity, and offer additional diagnostic or perfusion information. Laser doppler vibrometry measurements was performed on SPION containing tissue mimicking material during magnetic excitation. These measurements show a vibration amplitude of 279 ± 113 μm in a material with Young's modulus of 24.3 ± 2.8 kPa, while the displacements were substantially larger, 426 ± 9 μm, in the softer material, with a Young's modulus of 9.6 ± 0.8 kPa. Magnetic field measurement data was used to calibrate finite element modelling of both MMUS and CE-MMUS. SPION-MBs were shown to be capable of inducing larger tissue displacements under a given magnetic field than SPIONs alone, leading to axial displacements of up to 2.3x larger. A doubling in tissue stiffness (as may occur in cancer) reduces the vibration amplitude. Thus, there is potential for CE-MMUS to achieve improved stiffness sensitivity. Our aim is to define the potential contribution of CE-MMUS in colorectal cancer diagnosis and surgical guidance

Human saliva, plasma and breast milk exosomes contain RNA: uptake by macrophages

<p>Abstract</p> <p>Background</p> <p>Exosomes are 30-100 nm membrane vesicles of endocytic origin produced by numerous cells. They can mediate diverse biological functions, including antigen presentation. Exosomes have recently been shown to contain functional RNA, which can be delivered to other cells. Exosomes may thus mediate biological functions either by surface-to-surface interactions with cells, or by the delivery of functional RNA to cells. Our aim was therefore to determine the presence of RNA in exosomes from human saliva, plasma and breast milk and whether these exosomes can be taken up by macrophages.</p> <p>Method</p> <p>Exosomes were purified from human saliva, plasma and breast milk using ultracentrifugation and filtration steps. Exosomes were detected by electron microscopy and examined by flow cytometry. Flow cytometry was performed by capturing the exosomes on anti-MHC class II coated beads, and further stain with anti-CD9, anti-CD63 or anti-CD81. Breast milk exosomes were further analysed for the presence of Hsc70, CD81 and calnexin by Western blot. Total RNA was detected with a Bioanalyzer and mRNA was identified by the synthesis of cDNA using an oligo (dT) primer and analysed with a Bioanalyzer. The uptake of PKH67-labelled saliva and breast milk exosomes by macrophages was examined by measuring fluorescence using flow cytometry and fluorescence microscopy.</p> <p>Results</p> <p>RNA was detected in exosomes from all three body fluids. A portion of the detected RNA in plasma exosomes was characterised as mRNA. Our result extends the characterisation of exosomes in healthy humans and confirms the presence of RNA in human saliva and plasma exosomes and reports for the first time the presence of RNA in breast milk exosomes. Our results also show that the saliva and breast milk exosomes can be taken up by human macrophages.</p> <p>Conclusions</p> <p>Exosomes in saliva, plasma and breast milk all contain RNA, confirming previous findings that exosomes from several sources contain RNA. Furthermore, exosomes are readily taken up by macrophages, supporting the notion that exosomal RNA can be shuttled between cells.</p

Development of Preclinical Ultrasound Imaging Techniques to Identify and Image Sentinel Lymph Nodes in a Cancerous Animal Model

Lymph nodes (LNs) are believed to be the first organs targeted by colorectal cancer cells detached from a primary solid tumor because of their role in draining interstitial fluids. Better detection and assessment of these organs have the potential to help clinicians in stratification and designing optimal design of oncological treatments for each patient. Whilst highly valuable for the detection of primary tumors, CT and MRI remain limited for the characterization of LNs. B-mode ultrasound (US) and contrast-enhanced ultrasound (CEUS) can improve the detection of LNs and could provide critical complementary information to MRI and CT scans; however, the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) guidelines advise that further evidence is required before US or CEUS can be recommended for clinical use. Moreover, knowledge of the lymphatic system and LNs is relatively limited, especially in preclinical models. In this pilot study, we have created a mouse model of metastatic cancer and utilized 3D high-frequency ultrasound to assess the volume, shape, and absence of hilum, along with CEUS to assess the flow dynamics of tumor-free and tumor-bearing LNs in vivo. The aforementioned parameters were used to create a scoring system to predict the likelihood of a disease-involved LN before establishing post-mortem diagnosis with histopathology. Preliminary results suggest that a sum score of parameters may provide a more accurate diagnosis than the LN size, the single parameter currently used to predict the involvement of an LN in disease

Maverick dark matter at colliders

Assuming that dark matter is a weakly interacting massive particle (WIMP) species X produced in the early Universe as a cold thermal relic, we study the collider signal of pp or ppbar -> XXbar + jets and its distinguishability from standard-model background processes associated with jets and missing energy. We assume that the WIMP is the sole particle related to dark matter within reach of the LHC--a "maverick" particle--and that it couples to quarks through a higher dimensional contact interaction. We simulate the WIMP final-state signal XXbar + jet and dominant standard-model (SM) background processes and find that the dark-matter production process results in higher energies for the colored final state partons than do the standard-model background processes, resulting in more QCD radiation and a higher jet multiplicity. As a consequence, the detectable signature of maverick dark matter is an excess over standard-model expectations of events consisting of large missing transverse energy, together with large leading jet transverse momentum and scalar sum of the transverse momenta of the jets. Existing Tevatron data and forthcoming LHC data can constrain (or discover!) maverick dark matter.Comment: 11 pages, 7 figure

The Dapagliflozin and Prevention of Adverse-outcomes in Heart Failure (DAPA-HF) trial: baseline characteristics

The aims of this study were to: (i) report the baseline characteristics of patients enrolled in the Dapagliflozin And Prevention of Adverse-outcomes in Heart Failure (DAPA-HF) trial, (ii) compare DAPA-HF patients to participants in contemporary heart failure (HF) registries and in other recent HF trials, and (iii) compare individuals with diabetes, pre-diabetes and a normal glycated haemoglobin (HbA1c) in DAPA-HF. Adults with HF in New York Heart Association functional class ≥ II, a left ventricular ejection fraction ≤ 40%, an elevated N-terminal pro-B-type natriuretic peptide concentration and receiving standard treatment were eligible for DAPA-HF, which is comparing dapagliflozin 10 mg once daily to matching placebo. In patients without a history of diabetes, previously undiagnosed diabetes was defined as a confirmed HbA1c ≥ 6.5%. Among patients without known or undiagnosed diabetes, pre-diabetes was defined as a HbA1c ≥ 5.7% The remainder of patients, with a HbA1c &lt; 5.7%, were defined as normoglycaemic. Of the 4774 patients (mean age 66 years; 23% women) randomized, 42% had known diabetes and 3% undiagnosed diabetes. Of the remainder, 67% had pre-diabetes and 33% normal HbA1c. Overall, DAPA-HF patients were generally similar to those in recent registries and in relevant trials and had high levels of background therapy: 94% angiotensin-converting enzyme inhibitor/angiotensin receptor blocker/angiotensin receptor-neprilysin inhibitor, 96% beta-blocker, and 71% mineralocorticoid receptor antagonist; 26% had a defibrillator. Patients with diabetes had worse HF status, more co-morbidity, and greater renal impairment but received similar HF therapy. Patients with diabetes received non-insulin hypoglycaemic therapy alone in 49%, insulin alone in 11%, both in 14%, and none in 26%. Patients randomized in DAPA-HF were similar to those in other contemporary HF with reduced ejection fraction (HFrEF) registries and trials. These patients were receiving recommended HFrEF therapy and those with diabetes were also treated with conventional glucose-lowering therapy. Consequently, DAPA-HF will test the incremental efficacy and safety of dapagliflozin in HFrEF patients with and without diabetes

Loss of the Lupus Autoantigen Ro52/Trim21 Induces Tissue Inflammation and Systemic Autoimmunity by Disregulating the IL-23–Th17 Pathway

Ro52/Trim21 is targeted as an autoantigen in systemic lupus erythematosus and Sjögren's syndrome. Polymorphisms in the Ro52 gene have been linked to these autoimmune conditions, but the molecular mechanism by which Ro52 may promote development of systemic autoimmune diseases has not been explored. To address this issue, we generated Ro52-null mice ($Ro52^{−/−}$), which appear phenotypically normal if left unmanipulated. However, $Ro52^{−/−}$ mice develop severe dermatitis extending from the site of tissue injury induced by ear tags. The affected mice further develop several signs of systemic lupus with hypergammaglobulinemia, autoantibodies to DNA, proteinuria, and kidney pathology. Ro52, which was recently identified as an E3 ligase, mediates ubiquitination of several members of the interferon regulatory factor (IRF) family, and the Ro52-deficient mice have an enhanced production of proinflammatory cytokines that are regulated by the IRF transcription factors, including cytokines involved in the Th17 pathway (interleukin [IL] 6, IL-12/IL-23p40, and IL-17). Loss of IL-23/IL-17 by genetic deletion of IL-23/p19 in the $Ro52^{−/−}$ mice conferred protection from skin disease and systemic autoimmunity. These data reveal that the lupus-associated Ro52 protein is an important negative regulator of proinflammatory cytokine production, and they provide a mechanism by which a defective Ro52 function can lead to tissue inflammation and systemic autoimmunity through the IL-23–Th17 pathway

Effect of dapagliflozin in DAPA-HF according to background glucose-lowering therapy

Objective: To determine whether the benefits of dapagliflozin in patients with heart failure and reduced ejection fraction (HFrEF) and type 2 diabetes in the Dapagliflozin And Prevention of Adverse-Outcomes in Heart Failure trial (DAPA-HF) varied by background glucose-lowering therapy (GLT). Research Design and Methods: We examined the effect of study treatment by the use or not of GLT and by GLT classes and combinations. The primary outcome was a composite of worsening HF (hospitalization or urgent visit requiring intravenous therapy) or cardiovascular death. Results: In the 2,139 type 2 diabetes patients, the effect of dapagliflozin on the primary outcome was consistent by GLT use or no use (hazard ratio 0.72 [95% CI 0.58–0.88] versus 0.86 [0.60–1.23]; interaction P = 0.39) and across GLT classes. Conclusions: In DAPA-HF, dapagliflozin improved outcomes irrespective of use or no use of GLT or by GLT type used in patients with type 2 diabetes and HFrEF

Efficacy and safety of dapagliflozin in heart failure with reduced ejection fraction according to age: insights from DAPA-HF

Background: The DAPA-HF trial (Dapagliflozin and Prevention of Adverse-Outcomes in Heart Failure) showed that dapagliflozin added to other guideline-recommended therapies reduced the risk of mortality and heart failure hospitalization and improved symptoms in patients with heart failure and reduced ejection fraction. We examined the effects of dapagliflozin according to age, given potential concerns about the efficacy and safety of therapies in the elderly. Methods: Patients in New York Heart Association functional class II or greater with a left ventricular ejection fraction ≤40% and a modest elevation of NT-proBNP (N-terminal pro-B-type natriuretic peptide) were eligible. Key exclusion criteria included systolic blood pressure &lt;95 mm Hg and estimated glomerular filtration rate &lt;30 mL·min−1·1.73 m−2. The primary outcome was the composite of an episode of worsening heart failure (heart failure hospitalization or urgent heart failure visit) or cardiovascular death, whichever occurred first. Results: A total of 4744 patients 22 to 94 years of age (mean age, 66.3 [SD 10.9] years) were randomized: 636 patients (13.4%) were &lt;55 years of age, 1242 (26.2%) were 55 to 64 years of age, 1717 (36.2%) were 65 to 74 years of age, and 1149 (24.2%) were ≥75 years of age. The rate of the primary outcome (per 100 person-years, placebo arm) in each age group was 13.6 (95% CI, 10.4–17.9), 15.7 (95% CI, 13.2–18.7), 15.1 (95% CI, 13.1–17.5), and 18.0 (95% CI, 15.2–21.4) with corresponding dapagliflozin/placebo hazard ratios of 0.87 (95% CI, 0.60–1.28), 0.71 (95% CI, 0.55–0.93), 0.76 (95% CI, 0.61–0.95), and 0.68 (95% CI, 0.53–0.88; P for interaction=0.76). Consistent benefits were observed for the components of the primary outcome, all-cause mortality, and symptoms. Although adverse events and study drug discontinuation increased with age, neither was significantly more common with dapagliflozin in any age group. Conclusions: Dapagliflozin reduced the risk of death and worsening heart failure and improved symptoms across the broad spectrum of age studied in DAPA-HF. There was no significant imbalance in tolerability or safety events between dapagliflozin and placebo, even in elderly individuals

Contrast enhanced magneto-motive ultrasound in lymph nodes - modelling and pre-clinical imaging using magnetic microbubbles

Despite advances in MRI, the detection and characterisation of lymph nodes in rectal cancer remains complex, especially when assessing the response to neo-adjuvant treatment. An alternative approach is functional imaging, previously shown to aid characterization of cancer tissues. We report proof-of-concept of the novel technique Contrast-Enhanced Magneto-Motive Ultrasound (CE-MMUS) to recover information relating to local perfusion and lymphatic drainage, and interrogate tissue mechanical properties through magnetically induced tissue deformations. The feasibility of the proposed application was explored using a combination of pre-clinical ultrasound imaging and finite element analysis. First, contrast enhanced ultrasound imaging on one wild type mouse recorded lymphatic drainage of magnetic microbubbles after bolus injection. Second, preliminary CE-MMUS data were acquired as a proof of concept. Third, the magneto-mechanical interactions of a magnetic microbubble with an elastic solid were simulated using finite element software. Accumulation of magnetic microbubbles in the inguinal lymph node was verified using contrast enhanced ultrasound, with peak enhancement occurring 3.7 s post-injection. Preliminary CE-MMUS indicates the presence of magnetic contrast agent in the lymph node. The finite element analysis explores how the magnetic force is transferred to motion of the solid, which depends on elasticity and bubble radius, indicating an inverse relation with displacement. Combining magnetic microbubbles with MMUS could harness the advantages of both techniques, to provide perfusion information, robust lymph node delineation and characterisation based on mechanical properties. Clinical Relevance— Robust detection and characterisation of lymph nodes could be aided by visualising lymphatic drainage of magnetic microbubbles using contrast enhanced ultrasound imaging and magneto-motion, which is dependent on tissue mechanical properties