Uremia impairs the atheroprotective properties of HDL, but the mechanisms underlying why this occurs are unknown. Here, we observed that HDL isolated from healthy individuals inhibited the production of inflammatory cytokines by peripheral monocytes stimulated with a Toll-like receptor 2 agonist. In contrast, HDL isolated from the majority of patients with ESRD did not show this anti-inflammatory property; many HDL samples even promoted the production of inflammatory cytokines. To investigate this difference, we used shotgun proteomics to identify 49 HDL-associated proteins in a uremia-specific pattern. Proteins enriched in HDL from patients with ESRD (ESRD-HDL) included surfactant protein B (SP-B), apolipoprotein C-II, serum amyloid A (SAA), and a-1-microglobulin/bikunin precursor. In addition, we detected some ESRD-enriched proteins in earlier stages of CKD. We did not detect a difference in oxidation status between HDL isolated from uremic and healthy patients. Regarding function of these uremia-specific proteins, only SAA mimicked ESRD-HDL by promoting inflammatory cytokine production. Furthermore, SAA levels in ESRD-HDL inversely correlated with its anti-inflammatory potency. In conclusion, HDL has anti-inflammatory activities that are defective in uremic patients as a result of specific changes in its molecular composition. These data suggest a potential link between the high levels of inflammation and cardiovascular mortality in uremia.

Aggregation of hypertrophic macrophages constitutes the basis of all granulomatous diseases such as tuberculosis or sarcoidosis and is decisive for disease pathogenesis. However, macrophage-intrinsic pathways driving granuloma initiation and maintenance remain elusive. Here we show that activation of the metabolic checkpoint kinase mTORC1 in macrophages by deletion of Tsc2 was sufficient to induce hypertrophy and proliferation resulting in excessive granuloma formation in vivo. TSC2-deficient macrophages formed mTORC1-dependent granulomatous structures in vitro and showed constitutive proliferation mediated by the neo-expression of cyclin-dependent kinase 4 (CDK4). Moreover, mTORC1 promoted metabolic reprogramming via CDK4 towards increased glycolysis, while simultaneously inhibiting NF-κB signaling and apoptosis. Inhibition of mTORC1 induced apoptosis and completely resolved granulomas in myeloid TSC2-deficient mice. In human sarcoidosis patients mTORC1 activation, macrophage proliferation, and glycolysis were identified as hallmarks that correlated with clinical disease progression. Collectively, TSC2 maintains macrophage quiescence and prevents mTORC1-dependent granulomatous disease with clinical implications for sarcoidosis.

A central role for the mammalian target of rapamycin (mTOR) in innate immunity has been recently defined by its ability to limit proinflammatory mediators. Although glucocorticoids (GCs) exert potent anti-inflammatory effects in innate immune cells, it is currently unknown whether the mTOR pathway interferes with GC signaling. Here we show that inhibition of mTOR with rapamycin or Torin1 prevented the anti-inflammatory potency of GC both in human monocytes and myeloid dendritic cells. GCs could not suppress nuclear factor-B and JNK activation, the expression of proinflammatory cytokines, and the promotion of Th1 responses when mTOR was inhibited. Interestingly, long-term activation of monocytes with lipopolysaccharide enhanced the expression of TSC2, the principle negative regulator of mTOR, whereas dexamethasone blocked TSC2 expression and reestablished mTOR activation. IntroductionCurrent immunosuppressive regimens to avoid allogeneic rejection after organ or bone marrow transplantation largely rely on drugs with potent immunosuppressive effects predominantly affecting different steps during T-cell activation. There is, however, increasing evidence that also the innate immune system is critical for the fate of allografts and may as well exert detrimental effector functions. 1-9 For example, monocytes are the first cells to enter the allograft immediately after transplantation; and recently, monocyte influx, rather than T-cell influx, into the allograft has been proposed to correlate with graft rejection. 9 Monocytes, macrophages, and dendritic cells (DCs) initiate the inflammatory response after stimulation by Toll-like receptor (TLR) ligands and trigger the subsequent adaptive T-cell response. 10,11 However, the molecular pathways targeted by immunosuppressants in particular when they are used as combination therapy and the ensuing functional consequences are still incompletely defined.Among the currently used immunosuppressants calcineurin inhibitors (CNI), such as cyclosporine A (CsA) or FK506, and antimetabolites, such as mycophenolic acid (mycophenolate mofetil [MMF]) are thought to exert distinct but rather modest effects on innate immune cells. 12,13 On the contrary, glucocorticoids (GCs) have a high anti-inflammatory potential and, consequently, are crucial constituents of various immunosuppressive regimens applied in many inflammatory conditions. 14 GCs differentially affect cytokine production in monocytes/macrophages with a prominent shift toward an anti-inflammatory phenotype. 15 Furthermore, DC differentiation and maturation are profoundly suppressed by GCs, leading to DCs with a tolerizing capacity characterized by increased interleukin-10 (IL-10), but blocked IL-12 secretion. 16,17 At the molecular level, GCs profoundly inhibit nuclear factor-B (NF-B) signaling via the glucocorticoid receptor (GR) to prevent recruitment of active NF-B dimers to the B promoter. 18 Moreover, it has been demonstrated that the c-Jun N-terminal kinase (JNK) pathway that specifically leads to the activation of the tr...

Background MSA is characterized by deposition of alpha‐synuclein (α‐Syn) in oligodendrocytes and central nervous system (CNS) neurons. After recently detecting phospho‐α‐Syn (p‐α‐Syn) in dermal nerve fibers of patients with Parkinson's disease (PD), we assessed skin biopsies from patients with MSA to evaluate its potential role as a biomarker. Methods Skin biopsies of patients with MSA (n = 12), idiopathic PD (n = 30), tauopathies (n = 15), and normal controls (n = 39) were analyzed. P‐α‐Syn within dermal nerves was detected by immunofluorescence staining. Results p‐α‐Syn was found in 67% of patients with MSA and Parkinson's disease, but not in patients with tauopathy or controls when analyzing 15 consecutive sections. Sensitivity could be increased to 75% and 73%, respectively, by analyzing serial sections. In contrast to PD, where p‐α‐Syn clustered in autonomic fibers, deposits were mainly found in unmyelinated somatosensory fibers in MSA. Conclusion α‐Syn pathology in MSA is not restricted to the CNS, and skin biopsy may be useful for the premortem study of p‐α‐Syn. © 2015 International Parkinson and Movement Disorder Society

OBJECTIVEFlicker-induced vasodilatation is reduced in patients with vascular-related diseases, which has at least partially been attributed to endothelial dysfunction of retinal vessels. Currently, the standard method to assess endothelial function in vivo is flow-mediated vasodilatation (FMD). Thus, the present study was performed to investigate whether a correlation exists between flicker-induced vasodilatation and FMD in patients with known endothelial dysfunction and healthy subjects.RESEARCH DESIGN AND METHODSIn the present study, 20 patients with type 1 diabetes, 40 patients with systemic hypertension (systolic blood pressure 140–159 mmHg; diastolic blood pressure 90–99 mmHg) and/or serum cholesterol levels ≥0.65 mmol/l, and 20 healthy control subjects were included. The flicker response was measured using the Dynamic Retinal Vessel Analyzer. FMD was determined using a high-resolution ultrasound system, measuring brachial artery diameter reactivity during reperfusion after arterial occlusion.RESULTSThe flicker response of both retinal arteries and veins was significantly reduced in the two patients groups. Likewise, FMD was significantly reduced in patients compared with healthy control subjects. However, only a weak correlation between flicker-induced vasodilatation and FMD was observed.CONCLUSIONSThe study confirms that flicker responses and FMD are reduced in the selected patient groups. Whether the weak correlation between FMD and flicker is due to the different stimulation type, the different vascular beds measured, or other mechanisms has yet to be investigated.