Autoantibodies have been associated with autoimmune diseases. However, studies have identified autoantibodies in healthy donors (HD) who do not develop autoimmune disorders. Here we provide evidence of a network of immunoglobulin G (IgG) autoantibodies targeting G protein-coupled receptors (GPCR) in HD compared to patients with systemic sclerosis, Alzheimer’s disease, and ovarian cancer. Sex, age and pathological conditions affect autoantibody correlation and hierarchical clustering signatures, yet many of the correlations are shared across all groups, indicating alterations to homeostasis. Furthermore, we identify relationships between autoantibodies targeting structurally and functionally related molecules, such as vascular, neuronal or chemokine receptors. Finally, autoantibodies targeting the endothelin receptor type A (EDNRA) exhibit chemotactic activity, as demonstrated by neutrophil migration toward HD-IgG in an EDNRA-dependent manner and in the direction of IgG from EDNRA-immunized mice. Our data characterizing the in vivo signatures of anti-GPCR autoantibodies thus suggest that they are a physiological part of the immune system.

Many attempts to modulate leukocyte-endothelial interaction to prevent or reduce excessive inflammatory reactions were made in the past. However, the basic regulatory principles of the endothelial inflammatory process remain unclear. It seems that the inhibition of individual components of the inflammatory cascade, for example, by a single antibody against an adhesion molecule, may not be enough to achieve a sustained effect on vascular inflammation.In the past years, microRNAs have been identified as important regulators of gene expression in a wide range of Molecular Medicine© 2017 American Heart Association, Inc. Rationale:The interaction of circulating cells within the vascular wall is a critical event in chronic inflammatory processes, such as atherosclerosis, but the control of the vascular inflammatory state is still largely unclear.Objective: This study was undertaken to characterize the function of the endothelial-enriched microRNA miR-100 during vascular inflammation and atherogenesis. Methods and Results:Based on a transcriptome analysis of endothelial cells after miR-100 overexpression, we identified miR-100 as a potent suppressor of endothelial adhesion molecule expression, resulting in attenuated leukocyte-endothelial interaction in vitro and in vivo as shown by flow cytometry and intravital imaging. Mechanistically, miR-100 directly repressed several components of mammalian target of rapamycin complex 1-signaling, including mammalian target of rapamycin and raptor, which resulted in a stimulation of endothelial autophagy and attenuated nuclear factor κB signaling in vitro and in vivo. In a low-density lipoprotein receptordeficient atherosclerotic mouse model, pharmacological inhibition of miR-100 resulted in enhanced plaque lesion formation and a higher macrophage content of the plaque, whereas a systemic miR-100 replacement therapy had protective effects and attenuated atherogenesis, resulting in a decrease of plaque area by 45%. Finally, analysis of miR-100 expression in >70 samples obtained during carotid endarterectomy revealed that local miR-100 expression was inversely correlated with inflammatory cell content in patients. Conclusions: In summary, we describe an anti-inflammatory function of miR-100 in the vascular response to injury and inflammation and identify an important novel modulator of mammalian target of rapamycin signaling and autophagy

BRAF mutations are associated with aggressive, less-differentiated and therapy-resistant colorectal carcinoma. However, the underlying mechanisms for these correlations remain unknown. To understand how oncogenic B-Raf contributes to carcinogenesis, in particular to aspects other than cellular proliferation and survival, we generated three isogenic human colorectal carcinoma cell line models in which we can dynamically modulate the expression of the B-Raf V600E oncoprotein. Doxycyclin-inducible knockdown of endogenous B-Raf V600E decreases cellular motility and invasion in conventional and three-dimensional (3D) culture, whereas it promotes cell-cell contacts and induces various hallmarks of differentiated epithelia. Importantly, all these effects are recapitulated by B-Raf (PLX4720, vemurafenib, and dabrafenib) or MEK inhibitors (trametinib). Surprisingly, loss of B-Raf V600E in HT29 xenografts does not only stall tumor growth, but also induces glandular structures with marked expression of CDX2, a tumor-suppressor and master transcription factor of intestinal differentiation. By performing the first transcriptome profiles of PLX4720-treated 3D cultures of HT29 and Colo-205 cells, we identify several upregulated genes linked to epithelial differentiation and effector functions, such as claudin-1, a Cdx-2 target gene encoding a critical tight junction component. Thereby, we provide a mechanism for the clinically observed correlation between mutant BRAF and the loss of Cdx-2 and claudin-1. PLX4720 also suppressed several metastasis-associated transcripts that have not been implicated as targets, effectors or potential biomarkers of oncogenic B-Raf signaling so far. Together, we identify a novel facet of clinically applied B-Raf or MEK inhibitors by showing that they promote cellular adhesion and differentiation of colorectal carcinoma cells.

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