András Vida

Acute phase proteins in the diagnosis and prediction of cirrhosis associated bacterial infections

Bacterial infections are common cause of morbidity and mortality in patients with cirrhosis. The early diagnosis of these infections is rather difficult.

Identification of myeloid-derived suppressor cells in the synovial fluid of patients with rheumatoid arthritis: A pilot study

BackgroundMyeloid-derived suppressor cells (MDSCs) are a heterogeneous population of innate immune cells with a granulocyte-like or monocyte-like phenotype and a unique ability to suppress T-cell responses. MDSCs have been shown to accumulate in cancer patients, but recent studies suggest that these cells are also present in humans and animals suffering from autoimmune diseases. We previously identified MDSCs in the synovial fluid (SF) of mice with experimental autoimmune arthritis. The goal of the present study was to identify MDSCs in the SF of patients with rheumatoid arthritis (RA).MethodsRA SF cells were studied by flow cytometry using antibodies to MDSC cell surface markers as well as by analysis of cell morphology. The suppressor activity of RA SF cells toward autologous peripheral blood T cells was determined ex vivo. We employed both antigen-nonspecific (anti-CD3/CD28 antibodies) and antigen-specific (allogeneic cells) induction systems to test the effects of RA SF cells on the proliferation of autologous T cells.ResultsSF from RA patients contained MDSC-like cells, the majority of which showed granulocyte (neutrophil)-like phenotype and morphology. RA SF cells significantly suppressed the proliferation of anti-CD3/CD28-stimulated autologous T cells upon co-culture. When compared side by side, RA SF cells had a more profound inhibitory effect on the alloantigen-induced than the anti-CD3/CD28-induced proliferation of autologous T cells.ConclusionMDSCs are present among RA SF cells that are commonly regarded as inflammatory neutrophils. Our results suggest that the presence of neutrophil-like MDSCs in the SF is likely beneficial, as these cells have the ability to limit the expansion of joint-infiltrating T cells in RA.

Distinct effects of Re‐ and S‐forms of LPS on modulating platelet activation

271–83. 22 Janka GE. Familial and acquired hemophagocytic lymphohistiocytosis. Annu Rev Med 2012; 63: 233–46. 23 Shirakawa R, Higashi T, Tabuchi A, Yoshioka A, Nishioka H, Fukuda M, Kita T, Horiuchi H. Munc13-4 is a GTP-Rab27binding protein regulating dense core granule secretion in platelets. J Biol Chem 2004; 279: 10730–7. 24 Ren Q, Wimmer C, Chicka MC, Ye S, Ren Y, Hughson FM, Whiteheart SW. Munc13-4 is a limiting factor in the pathway required for platelet granule release and hemostasis. Blood 2010; 116: 869–77. 25 Smith SA, Mutch NJ, Baskar D, Rohloff P, Docampo R, Morrissey JH. Polyphosphate modulates blood coagulation and fibrinolysis. Proc Natl Acad Sci USA 2006; 103: 903–8.

Suppression of Proteoglycan-Induced Autoimmune Arthritis by Myeloid-Derived Suppressor Cells Generated In Vitro from Murine Bone Marrow

Background Myeloid-derived suppressor cells (MDSCs) are innate immune cells capable of suppressing T-cell responses. We previously reported the presence of MDSCs with a granulocytic phenotype in the synovial fluid (SF) of mice with proteoglycan (PG)-induced arthritis (PGIA), a T cell-dependent autoimmune model of rheumatoid arthritis (RA). However, the limited amount of SF-MDSCs precluded investigations into their therapeutic potential. The goals of this study were to develop an in vitro method for generating MDSCs similar to those found in SF and to reveal the therapeutic effect of such cells in PGIA. Methods Murine bone marrow (BM) cells were cultured for 3 days in the presence of granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin-6 (IL-6), and granulocyte colony-stimulating factor (G-CSF). The phenotype of cultured cells was analyzed using flow cytometry, microscopy, and biochemical methods. The suppressor activity of BM-MDSCs was tested upon co-culture with activated T cells. To investigate the therapeutic potential of BM-MDSCs, the cells were injected into SCID mice at the early stage of adoptively transferred PGIA, and their effects on the clinical course of arthritis and PG-specific immune responses were determined. Results BM cells cultured in the presence of GM-CSF, IL-6, and G-CSF became enriched in MDSC-like cells that showed greater phenotypic heterogeneity than MDSCs present in SF. BM-MDSCs profoundly inhibited both antigen-specific and polyclonal T-cell proliferation primarily via production of nitric oxide. Injection of BM-MDSCs into mice with PGIA ameliorated arthritis and reduced PG-specific T-cell responses and serum antibody levels. Conclusions Our in vitro enrichment strategy provides a SF-like, but controlled microenvironment for converting BM myeloid precursors into MDSCs that potently suppress both T-cell responses and the progression of arthritis in a mouse model of RA. Our results also suggest that enrichment of BM in MDSCs could improve the therapeutic efficacy of BM transplantation in RA.

Metabolic roles of poly(ADP-ribose) polymerases

Poly(ADP-ribosyl)ation (PARylation) is an evolutionarily conserved reaction that had been associated with numerous cellular processes such as DNA repair, protein turnover, inflammatory regulation, aging or metabolic regulation. The metabolic regulatory tasks of poly(ADP-ribose) polymerases (PARPs) are complex, it is based on the regulation of metabolic transcription factors (e.g. SIRT1, nuclear receptors, SREBPs) and certain cellular energy sensors. PARP over-activation can cause damage to mitochondrial terminal oxidation, while the inhibition of PARP-1 or PARP-2 can induce mitochondrial oxidation by enhancing the mitotropic tone of gene transcription and signal transduction. These PARP-mediated processes impact on higher order metabolic regulation that modulates lipid metabolism, circadian oscillations and insulin secretion and signaling. PARP-1, PARP-2 and PARP-7 are related to metabolic diseases such as diabetes, alcoholic and non-alcoholic fatty liver disease (AFLD, NAFLD), or on a broader perspective to Warburg metabolism in cancer or the metabolic diseases accompanying aging.

AMP-Activated Kinase (AMPK) Activation by AICAR in Human White Adipocytes Derived from Pericardial White Adipose Tissue Stem Cells Induces a Partial Beige-Like Phenotype.

Beige adipocytes are special cells situated in the white adipose tissue. Beige adipocytes, lacking thermogenic cues, morphologically look quite similar to regular white adipocytes, but with a markedly different response to adrenalin. White adipocytes respond to adrenergic stimuli by enhancing lipolysis, while in beige adipocytes adrenalin induces mitochondrial biogenesis too. A key step in the differentiation and function of beige adipocytes is the deacetylation of peroxisome proliferator-activated receptor (PPARγ) by SIRT1 and the consequent mitochondrial biogenesis. AMP-activated protein kinase (AMPK) is an upstream activator of SIRT1, therefore we set out to investigate the role of AMPK in beige adipocyte differentiation using human adipose-derived mesenchymal stem cells (hADMSCs) from pericardial adipose tissue. hADMSCs were differentiated to white and beige adipocytes and the differentiation medium of the white adipocytes was supplemented with 100 μM [(2R,3S,4R,5R)-5-(4-Carbamoyl-5-aminoimidazol-1-yl)-3,4-dihydroxyoxolan-2-yl]methyl dihydrogen phosphate (AICAR), a known activator of AMPK. The activation of AMPK with AICAR led to the appearance of beige-like morphological properties in differentiated white adipocytes. Namely, smaller lipid droplets appeared in AICAR-treated white adipocytes in a similar fashion as in beige cells. Moreover, in AICAR-treated white adipocytes the mitochondrial network was more fused than in white adipocytes; a fused mitochondrial system was characteristic to beige adipocytes. Despite the morphological similarities between AICAR-treated white adipocytes and beige cells, functionally AICAR-treated white adipocytes were similar to white adipocytes. We were unable to detect increases in basal or cAMP-induced oxygen consumption rate (a marker of mitochondrial biogenesis) when comparing control and AICAR-treated white adipocytes. Similarly, markers of beige adipocytes such as TBX1, UCP1, CIDEA, PRDM16 and TMEM26 remained the same when comparing control and AICAR-treated white adipocytes. Our data point out that in human pericardial hADMSCs the role of AMPK activation in controlling beige differentiation is restricted to morphological features, but not to actual metabolic changes.

Glycogen phosphorylase inhibition improves beta cell function

Glycogen phosphorylase (GP) is the key enzyme for glycogen degradation. GP inhibitors (GPi‐s) are glucose lowering agents that cause the accumulation of glucose in the liver as glycogen. Glycogen metabolism has implications in beta cell function. Glycogen degradation can maintain cellular glucose levels, which feeds into catabolism to maintain insulin secretion, and elevated glycogen degradation levels contribute to glucotoxicity. The purpose of this study was to assess whether influencing glycogen metabolism in beta cells by GPi‐s affects the function of these cells.

PARP10 (ARTD10) modulates mitochondrial function

Poly(ADP-ribose) polymerase (PARP)10 is a PARP family member that performs mono-ADP-ribosylation of target proteins. Recent studies have linked PARP10 to metabolic processes and metabolic regulators that prompted us to assess whether PARP10 influences mitochondrial oxidative metabolism. The depletion of PARP10 by specific shRNAs increased mitochondrial oxidative capacity in cellular models of breast, cervical, colorectal and exocrine pancreas cancer. Upon silencing of PARP10, mitochondrial superoxide production decreased in line with increased expression of antioxidant genes pointing out lower oxidative stress upon PARP10 silencing. Improved mitochondrial oxidative capacity coincided with increased AMPK activation. The silencing of PARP10 in MCF7 and CaCo2 cells decreased the proliferation rate that correlated with increased expression of anti-Warburg enzymes (Foxo1, PGC-1α, IDH2 and fumarase). By analyzing an online database we showed that lower PARP10 expression increases survival in gastric cancer. Furthermore, PARP10 expression decreased upon fasting, a condition that is characterized by increases in mitochondrial biogenesis. Finally, lower PARP10 expression is associated with increased fatty acid oxidation.

Comparative preclinical evaluation of 68Ga-NODAGA and 68Ga-HBED-CC conjugated procainamide in melanoma imaging

HIGHLIGHTSRadiolabeled benzamide derivatives can play an important role in melanoma imaging.68Ga‐labeled procainamide derivatives showed high melanin specificity.Procainamide was conjugated with 68Ga‐labeled NODAGA and HBED‐CC chelators.Properties of the chelators determines the biological behaviour of the probe. ABSTRACT Malignant melanoma is the most aggressive form of skin cancer. The early detection of primary melanoma tumors and metastases using non‐invasive PET imaging determines the outcome of this disease. Previous studies have shown that benzamide derivatives (e.g. procainamide) conjugated with PET radionuclides specifically bind to melanin pigment of melanoma tumors. 68Ga chelating agents can have high influence on physiological properties of 68Ga labeled bioactive molecules, as was experienced during the application of HBED‐CC on PSMA ligand. The aim of this study was to assess this concept in the case of the melanin specific procaindamide (PCA) and to compare the melanin specificity of 68Ga‐labeled PCA using HBED‐CC and NODAGA chelators under in vitro and in vivo conditions. Procainamide (PCA) was conjugated with HBED‐CC and NODAGA chelators and was labeled with Ga‐68. The melanin specificity of 68Ga‐HBED‐CC‐PCA and 68Ga‐NODAGA‐PCA was investigated in vitro and in vivo using amelanotic (MELUR and A375) and melanin containing (B16‐F10) melanoma cell lines. Tumor‐bearing mice were prepared by subcutaneous injection of B16‐F10, MELUR and A375 melanoma cells into C57BL/6 and SCID mice. 21 ± 2 days after tumor cell inoculation and 90 min after intravenous injection of the 68Ga‐labelledlabeled radiopharmacons whole body PET/MRI scans were performed. 68Ga‐NODAGA‐PCA and 68Ga‐HBED‐CC‐PCA were produced with excellent radiochemical purity (98%). In vitro experiments demonstrated that after 30 and 90 min incubation time 68Ga‐NODAGA‐PCA uptake of B16‐F10 cells was significantly (p ≤ 0.01) higher than the 68Ga‐HBED‐CC‐conjugated PCA accumulation in the same cell line. Furthermore, significant difference (p ≤ 0.01 and 0.05) was found between the uptake of melanin negative and positive cell lines using 68Ga‐NODAGA‐PCA and 68Ga‐HBED‐CC‐PCA. In vivo PET/MRI studies using tumor models revealed significantly (p ≤ 0.01) higher 68Ga‐NODAGA‐PCA uptake (SUVmean: 0.46 ± 0.05, SUVmax: 1.96 ± 0.25, T/M ratio: 40.7 ± 4.23) in B16‐F10 tumors in contrast to 68Ga‐HBED‐CC‐PCA where the SUVmean, SUVmax and T/M ratio were 0.13 ± 0.01, 0.56 ± 0.11 and 11.43 ± 1.24, respectively. Melanin specific PCA conjugated with NODAGA chelator showed higher specific binding properties than conjugated with HBED‐CC. The chemical properties of the bifunctional chelators used for 68Ga‐labeling of PCA determine the biological behaviour of the probes. Due to the high specificity and sensitivity 68Ga‐labeled PCA molecules are promising radiotracers in melanoma imaging.

Translational aspects of the microbiome—to be exploited

The scope of Cell Biology and Toxicology had been opened towards translational research as was discussed in the editorial of the Xiandong Wang (Gu and Wang 2016). Translational research supports the close collaboration of different specialties ranging from basic science research to clinical studies. That approach may shorten the time it takes for developing new treatment possibilities or schemes. To better understand the complexity of such methodology, hereby we review an exciting field, the microbiome—from a translational point of view (Fig. 1). The human body harbors symbiotic, commensal and pathogenic bacteria in enormous numbers. These microbes live in the cavities (e.g., gut, genitals, or airways) or on the surface of the human body, the skin. The ensemble of the microbes in an organism is referred as the normal flora. Changes in the composition of the normal flora, the invasion or over-proliferation of pathogenic bacteria had long been associated with diseases (e.g., Helicobacter pylori infection of the stomach) and had been translated already to the everyday clinical practice. Recent developments in research technology have vastly increased our knowledge on the Bnormal flora,^Next generation highthroughput sequencing experiments have demonstrated that there are more bacterial species in the gut than it was known from classical microbiological cultures. These studies have identified numerous new bacterial species, among them several obligatory anaerobic strains that are impossible to culture. The ensemble of microbes in a compartment (e.g., gut or airways), identified by sequencing, is referred as the microbiome or microbiota. Due to the abundance and variance of microbes, the overall size of the genomes of these organisms exceeds that of the human genome, extending vastly the variability of genes in a compartment. Therefore, several authors consider the microbiome as an additional organ and recently proposed to consider the ensemble of the human and microbial genomes present in one human being the Bmetagenome.^ There is an intricate bidirectional interaction between the host and the microbiome. The composition of the microbiome is governed by the behavior (e.g., hygiene), feeding, metabolism, and immunological characteristics of the host. While the microbiome influences host metabolism, immune reactions, and behavior through (1) releasing its own metabolites (e.g., short chain fatty acids), (2) modifying themetabolites of the host (e.g., secondary bile acids, primary amines, metabolites of aromatic amino acids (e.g., Trp), lactate, pyruvate, redox-modified sex steroids or polyphenols), (3) metabolizing nutrients (e.g., dietary fibers), or (4) synthesizing vitamins and Cell Biol Toxicol (2016) 32:153–156 DOI 10.1007/s10565-016-9320-6