Changes in Endocan and Dermatan Sulfate Are Associated with Biomechanical Properties of Abdominal Aortic Wall during Aneurysm Expansion and Rupture.

BACKGROUND AND AIMS: The study aimed to assess the potential of proteoglycans (PGs) and collagens as serological biomarkers in the abdominal aortic aneurysm (AAA). Furthermore, we investigated the underlying mechano-biological interactions and signaling pathways. METHODS: Tissue and serum samples from patients with ruptured AAA (rAAA; n = 29), elective AAA (eAAA; n = 78), and healthy individuals (n = 8) were evaluated by histology, immunohistochemistry, and enzyme-linked immunosorbent assay, and mechanical properties were assessed by tensile tests. Regulatory pathways were determined by membrane-based sandwich immunoassay. RESULTS: In AAA samples, collagen type I and III (Col1 and Col3), chondroitin sulfate, and dermatan sulfate (DS) were significantly increased compared with controls (3.0-, 3.2-, 1.3-, and 53-fold; p < 0.01). Col1 and endocan were also elevated in the serum of AAA patients (3.6- and 6.0-fold; p < 0.01), while DS was significantly decreased (2.5-fold; p < 0.01). Histological scoring showed increased total PGs and focal accumulation in rAAA compared with eAAA. Tissue ß-stiffness was higher in rAAA compared with eAAA (2.0-fold, p = 0.02). Serum Col1 correlated with maximum tensile force and failure tension (r = 0.448 and 0.333; p < 0.01, and r = 0.02), tissue endocan correlated with α-stiffness (r = 0.340; p < 0.01). Signaling pathways in AAA were associated with extracellular matrix synthesis and vascular smooth muscle cell proliferation. In particular, Src family kinases and platelet-derived growth factor- and epidermal growth factor-related proteins seem to be involved. CONCLUSION: Our findings reveal a structural association between collagen and PGs and their response to changes in mechanical loads in AAA. Particularly Col1 and endocan reflect the mechano-biological conditions of the aortic wall also in the patient's serum and might serve for AAA risk stratification.

Molecular magnetic resonance imaging of activated platelets allows noninvasive detection of early myocarditis in mice.

MRI sensitivity for diagnosis and localization of early myocarditis is limited, although it is of central clinical interest. The aim of this project was to test a contrast agent targeting activated platelets consisting of microparticles of iron oxide (MPIO) conjugated to a single-chain antibody directed against ligand-induced binding sites (LIBS) of activated glycoprotein IIb/IIIa (= LIBS-MPIO). Myocarditis was induced by subcutaneous injection of an emulsion of porcine cardiac myosin and complete Freund's adjuvant in mice. 3D 7 T in-vivo MRI showed focal signal effects in LIBS-MPIO injected mice 2 days after induction of myocarditis, whereas in control-MPIO injected mice no signal was detectable. Histology confirmed CD41-positive staining, indicating platelet involvement in myocarditis in mice as well as in human specimens with significantly higher LIBS-MPIO binding compared to control-MPIO in both species. Quantification of the myocardial MRI signal confirmed a signal decrease after LIBS-MPIO injection and significant less signal in comparison to control-MPIO injection. These data show, that platelets are involved in inflammation during the course of myocarditis in mice and humans. They can be imaged non-invasively with LIBS-MPIO by molecular MRI at an early time point of the inflammation in mice, which is a valuable approach for preclinical models and of interest for both diagnostic and prognostic purposes.

Lipid Mediators From Timothy Grass Pollen Contribute to the Effector Phase of Allergy and Prime Dendritic Cells for Glycolipid Presentation.

Plant pollen are an important source of antigens that evoke allergic responses. Protein antigens have been the focus of studies aiming to elucidate the mechanisms responsible for allergic reactions to pollen. However, proteins are not the sole active agent present in pollen. It is known that pollen grains contain lipids essential for its reproduction and bioactive lipid mediators. These small molecular compounds are co-delivered with the allergens and hence have the potential to modulate the immune response of subjects by activating their innate immune cells. Previous reports showed that pollen associated lipid mediators exhibited neutrophil- and eosinophil-chemotactic activity and induced polarization of dendritic cells (DCs) toward a Th2-inducing phenotype. In our study we performed chemical analyses of the pollen associated lipids, that are rapidly released upon hydration. As main components we have identified different types of phytoprostanes (PhytoPs), and for the first time phytofurans (PhytoFs), with predominating 16-F1t-PhytoPs (PPF1-I), 9-F1t-PhytoPs (PPF1-II), 16-E1t-PhytoPs (PPE1-I) and 9-D1t-PhytoPs (PPE1-II), and 16(RS)-9-epi-ST-Δ14-10-PhytoFs. Interestingly 16-E1t-PhytoP and 9-D1t-PhytoPs were found to be bound to glycerol. Lipid-containing samples (aqueous pollen extract, APE) induced murine mast cell chemotaxis and IL-6 release, and enhanced their IgE-dependent degranulation, demonstrating a role for these lipids in the immediate effector phase of allergic inflammation. Noteworthy, mast cell degranulation seems to be dependent on glycerol-bound, but not free phytoprostanes. On murine dendritic cells, APE selectively induced the upregulation of CD1d, likely preparing lipid-antigen presentation to iNKT cells. Our report contributes to the understanding of the activity of lipid mediators in the immediate effector phase of allergic reactions but identifies a yet undescribed pathway for the recognition of pollen-derived glycolipids by iNKT cells.

Glycogen synthase kinase is a regulator of the circadian clock of Neurospora crassa.

Timekeeping by circadian clocks relies upon precise adjustment of expression levels of clock proteins. Here we identify glycogen synthase kinase (GSK) as a novel and critical component of the circadian clock of Neurospora crassa that regulates the abundance of its core transcription factor white collar complex (WCC) on a post-transcriptional level. We show that GSK specifically binds and phosphorylates both subunits of the WCC. Reduced expression of GSK promotes an increased accumulation of WC-1, the limiting factor of the WCC, causing an acceleration of the circadian clock and a shorter free-running period.