These results suggest that CPC-secreted exosomes may be more cardioprotective than BMC-secreted exosomes, and that PAPP-A-mediated IGF-1 release may explain the benefit. They illustrate a general mechanism whereby exosomes may function via an active protease on their surface, which releases a ligand in proximity to the transmembrane receptor bound by the ligand.

SummaryHuman CD4+CD25hiFoxp3+CD127− Treg and CD4+CD25−Foxp3− Tconv cell functions are governed by their metabolic requirements. Here we report a comprehensive comparative analysis between ex vivo human Treg and Tconv cells that comprises analyses of the proteomic networks in subcellular compartments. We identified a dominant proteomic signature at the metabolic level that primarily impacted the highly-tuned balance between glucose and fatty-acid oxidation in the two cell types. Ex vivo Treg cells were highly glycolytic while Tconv cells used predominantly fatty-acid oxidation (FAO). When cultured in vitro, Treg cells engaged both glycolysis and FAO to proliferate, while Tconv cell proliferation mainly relied on glucose metabolism. Our unbiased proteomic analysis provides a molecular picture of the impact of metabolism on ex vivo human Treg versus Tconv cell functions that might be relevant for therapeutic manipulations of these cells.

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Systemic light chain amyloidosis (AL)  is a life-threatening disease caused by aggregation and deposition of monoclonal immunoglobulin light chains (LC) in target organs. Severity of heart involvement is the most important factor determining prognosis. Here, we report the 4.0 Å resolution cryo-electron microscopy map and molecular model of amyloid fibrils extracted from the heart of an AL amyloidosis patient with severe amyloid cardiomyopathy. The helical fibrils are composed of a single protofilament, showing typical 4.9 Å stacking and cross-β architecture. Two distinct polypeptide stretches (total of 77 residues) from the LC variable domain (Vl) fit the fibril density. Despite Vl high sequence variability, residues stabilizing the fibril core are conserved through different cardiotoxic Vl, highlighting structural motifs that may be common to misfolding-prone LCs. Our data shed light on the architecture of LC amyloids, correlate amino acid sequences with fibril assembly, providing the grounds for development of innovative medicines.

Neurotransmitter-neuroendocrine and cardiovascular responses to the administration of a psychologically stressful mixed-model test (Mental Arithmetic, Stroop Color Word Interference Task, Trier Social Stress Test) were examined in 20 male peripubertal subjects affected by anxiety disorder (group A: 14 with generalized anxiety disorder, 6 with generalized anxiety disorder and separation anxiety disorder) and 20 junior school adolescents, matched for age, without overt psychological disorders (group B). Plasma levels of norepinephrine (NE), epinephrine (EPI), adrenocorticotropic hormone (ACTH), β-endorphin (β-EP), cortisol (CORT), growth hormone (GH), prolactin (PRL) and testosterone (Te) were measured immediately before the beginning of the tests and 30 min later at their end. Mean prestress values of GH, PRL, β-EP and ACTH were significantly higher in anxious subjects than in controls. There was no difference in NE, EPI, CORT and Te prestress levels in the two groups. After the psychological stress session NE, GH and Te concentrations increased significantly in anxious subjects (A), but not in controls. In contrast, β-EP and PRL decreased significantly during the psychological stress session in anxious subjects, and were unaffected by stress in the subjects without anxiety. No significant changes were found in ACTH, CORT and EPI during the challenge either in anxious subjects or in controls, which may be attributed to the late time of poststress blood sampling. In contrast to controls, heart rate and systolic blood pressure increased significantly in anxious subjects after psychological stress testing. Our data support the hypothesis that the hyperactivity of the noradrenergic system in response to stress is associated with anxiety disorders in adolescents and might influence the responses of GH and Te. High prestress basal values of stress hormones seem to be induced in anxious subjects by the anticipation of the task or by a persistent hyperactivity of the noradrenergic system. Further studies are needed to investigate in more detail the involvement of the HPA axis in anxious adolescents by a more refined resolution of time points of blood sampling.