Fetuin-A is a liver derived plasma protein showing highest serum concentrations in utero, preterm infants, and neonates. Fetuin-A is also present in cerebrospinal fluid (CSF). The origin of CSF ...fetuin-A, blood-derived via the blood-CSF barrier or synthesized intrathecally, is presently unclear. Fetuin-A prevents ectopic calcification by stabilizing calcium and phosphate as colloidal calciprotein particles mediating their transport and clearance. Thus, fetuin-A plays a suppressive role in inflammation. Fetuin-A is a negative acute-phase protein under investigation as a biomarker for multiple sclerosis (MS). Here we studied the association of pediatric inflammatory CNS diseases with fetuin-A glycosylation and phosphorylation. Paired blood and CSF samples from 66 children were included in the study. Concentration measurements were performed using a commercial human fetuin-A/AHSG ELISA. Of 60 pairs, 23 pairs were analyzed by SDS-PAGE following glycosidase digestion with PNGase-F and Sialidase-AU. Phosphorylation was analyzed in 43 pairs by Phos-Tag.sup.TM acrylamide electrophoresis following alkaline phosphatase digestion. Mean serum and CSF fetuin-A levels were 0.30 ± 0.06 mg/ml and 0.644 ± 0.55 mug/ml, respectively. This study showed that serum fetuin-A levels decreased in inflammation corroborating its role as a negative acute-phase protein. Blood-CSF barrier disruption was associated with elevated fetuin-A in CSF. A strong positive correlation was found between the CSF fetuin-A/serum fetuin-A quotient and the CSF albumin/serum albumin quotient, suggesting predominantly transport across the blood-CSF barrier rather than intrathecal fetuin-A synthesis. Sialidase digestion showed increased asialofetuin-A levels in serum and CSF samples from children with neuroinflammatory diseases. Desialylation enhanced hepatic fetuin-A clearance via the asialoglycoprotein receptor thus rapidly reducing serum levels during inflammation. Phosphorylation of fetuin-A was more abundant in serum samples than in CSF, suggesting that phosphorylation may regulate fetuin-A influx into the CNS. These results may help establish Fetuin-A as a potential biomarker for neuroinflammatory diseases.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Intrauterine growth restriction (IUGR) is associated with reduced kidney size at birth, accelerated renal function decline, and increased risk for chronic kidney and cardiovascular diseases in ...adults. Precise mechanisms underlying fetal programming of adult diseases remain largely elusive and warrant extensive investigation. Setting up a mouse model of hypoxia-induced IUGR, fetal adaptations at mRNA, protein and cellular levels, and their long-term functional consequences are characterized, using the kidney as a readout. Here, we identify fetuin-A as an evolutionary conserved HIF target gene, and further investigate its role using fetuin-A KO animals and an adult model of ischemia-reperfusion injury. Beyond its role as systemic calcification inhibitor, fetuin-A emerges as a multifaceted protective factor that locally counteracts calcification, modulates macrophage polarization, and attenuates inflammation and fibrosis, thus preserving kidney function. Our study paves the way to therapeutic approaches mitigating mineral stress-induced inflammation and damage, principally applicable to all soft tissues.
Gold nanoparticles (AuNPs) are generally considered nontoxic, similar to bulk gold, which is inert and biocompatible. AuNPs of diameter 1.4 nm capped with triphenylphosphine monosulfonate (TPPMS), ...Au1.4MS, are much more cytotoxic than 15‐nm nanoparticles (Au15MS) of similar chemical composition. Here, major cell‐death pathways are studied and it is determined that the cytotoxicity is caused by oxidative stress. Indicators of oxidative stress, reactive oxygen species (ROS), mitochondrial potential and integrity, and mitochondrial substrate reduction are all compromised. Genome‐wide expression profiling using DNA gene arrays indicates robust upregulation of stress‐related genes after 6 and 12 h of incubation with a 2 × IC50 concentration of Au1.4MS but not with Au15MS nanoparticles. The caspase inhibitor Z‐VAD‐fmk does not rescue the cells, which suggests that necrosis, not apoptosis, is the predominant pathway at this concentration. Pretreatment of the nanoparticles with reducing agents/antioxidants N‐acetylcysteine, glutathione, and TPPMS reduces the toxicity of Au1.4MS. AuNPs of similar size but capped with glutathione (Au1.1GSH) likewise do not induce oxidative stress. Besides the size dependency of AuNP toxicity, ligand chemistry is a critical parameter determining the degree of cytotoxicity. AuNP exposure most likely causes oxidative stress that is amplified by mitochondrial damage. Au1.4MS nanoparticle cytotoxicity is associated with oxidative stress, endogenous ROS production, and depletion of the intracellular antioxidant pool.
Cells set alight: Ultrasmall triphenylphosphine‐capped gold nanoparticles continuously generate reactive oxygen species, which trigger leakiness of mitochondria and cell necrosis. This is visualized by discharge into the cytoplasm of green monomeric JC‐1 stain from mitochondria (see picture), where it exists as a red dimer in undamaged cells.
Size-Dependent Cytotoxicity of Gold Nanoparticles Pan, Yu; Neuss, Sabine; Leifert, Annika ...
Small (Weinheim an der Bergstrasse, Germany),
November 5, 2007, Letnik:
3, Številka:
11
Journal Article
Recenzirano
Gold nanoparticles are widely used in biomedical imaging and diagnostic tests. Based on their established use in the laboratory and the chemical stability of Au0, gold nanoparticles were expected to ...be safe. The recent literature, however, contains conflicting data regarding the cytotoxicity of gold nanoparticles. Against this background a systematic study of water‐soluble gold nanoparticles stabilized by triphenylphosphine derivatives ranging in size from 0.8 to 15 nm is made. The cytotoxicity of these particles in four cell lines representing major functional cell types with barrier and phagocyte function are tested. Connective tissue fibroblasts, epithelial cells, macrophages, and melanoma cells prove most sensitive to gold particles 1.4 nm in size, which results in IC50 values ranging from 30 to 56 μM depending on the particular 1.4‐nm Au compound–cell line combination. In contrast, gold particles 15 nm in size and Tauredon (gold thiomalate) are nontoxic at up to 60‐fold and 100‐fold higher concentrations, respectively. The cellular response is size dependent, in that 1.4‐nm particles cause predominantly rapid cell death by necrosis within 12 h while closely related particles 1.2 nm in diameter effect predominantly programmed cell death by apoptosis.
Size matters: A cytotoxicity study of triphenylphosphine‐capped gold nanoparticles ranging in size from 0.8 to 15 nm showed that gold particles 1.4 nm in size are much more toxic than smaller and larger particles tested across four different cell lines (see picture; IC50=inhibitory concentration that effected 50 % growth inhibition).
Pathogen‐ and injury‐related danger signals as well as cytokines released by immune cells influence the functional differentiation of macrophages in chronic inflammation. Recently, the liver‐derived ...plasma protein, histidine‐rich glycoprotein (HRG), was demonstrated, in mouse tumor models, to mediate the transition of alternatively activated (M2) to proinflammatory (M1) macrophages, which limit tumor growth and metastasis. We hypothesized that liver‐derived HRG is a critical endogenous modulator of hepatic macrophage functionality and investigated its implications for liver inflammation and fibrosis by comparing C57BL/6N wild‐type (WT) and Hrg−/− mice. In homeostatic conditions, hepatic macrophages were overall reduced and preferentially polarized toward the anti‐inflammatory M2 subtype in Hrg−/− mice. Upon chronic liver damage induced by CCl4 or methionine‐choline‐deficient (MCD) diet, liver injury and fibrosis were attenuated in Hrg−/−, compared to WT, mice. Macrophage populations were reduced and skewed toward M2 polarization in injured livers of Hrg−/− mice. Moreover, HRG‐deficient mice showed significantly enhanced hepatic vascularization by micro‐computed tomography and histology, corroborating proangiogenic activities of M2‐polarized liver macrophages. Purified HRG protein induced, but HRG‐deficient serum prevented, M1 macrophage differentiation in vitro. Accordingly, Hrg−/− mice transplanted with Hrg+/+ bone marrow, but not Hrg−/−‐transplanted Hrg+/+ mice, remained protected from experimental steatohepatitis. Consistent with these findings, patients with chronic hepatitis C and nonalcoholic steatohepatitis significantly up‐regulated hepatocytic HRG expression, which was associated with M1 polarization of adjacent macrophages. Conclusions: Liver‐derived HRG, similar to alarmins, appears to be an endogenous molecular factor promoting polarization of hepatic macrophages toward the M1 phenotype, thereby promoting chronic liver injury and fibrosis progression, but limiting angiogenesis. Therefore, controlling tissue levels of HRG or PGF might be a promising strategy in chronic inflammatory liver diseases. (Hepatology 2016;63:1310‐1324)
Mineralization in higher vertebrates is restricted to bones and teeth. Pathological calcification is mostly known in vasculature but can basically affect all soft tissues. Simply put, tissue ...mineralization occurs through the interplay of three key determinants: extracellular matrix suitable for mineralization, extracellular levels of inorganic phosphate and calcium, and the levels of mineralization inhibitors that may be expressed systemically or locally. In this article we describe the role of a prototypic systemic inhibitor protein of mineralization, the hepatic plasma protein α
2
-Heremans-Schmid glycoprotein/fetuin-A. Fetuin-A mediates the formation of stable colloidal mineral–protein complexes called calciprotein particles (CPPs). Thus, fetuin-A is important in the stabilization and clearance of amorphous mineral precursor phases. Efficient clearance of CPPs and, thus, of excess mineral from circulation prevents local buildup of mineral and calcification of soft tissue. Besides calcium phosphate binding, fetuin-A also acts as a carrier for lipids, which may influence calcification, inflammation, and apoptosis. Fetuin-A-deficient (
Ahsg
−
/
−
) mice show impaired growth of their long bones and premature growth plate closure. We posit that the absence of fetuin-A in the growth plate causes simultaneous lack of calcification inhibition and excess lipid hormone signaling, leading to premature growth plate mineralization and shortened long bones. This suggests that fetuin-A regulates endochondral ossification through mineralization inhibition and lipid (hormone) binding.
Background
Clinical experience indicates that wounds in alveolar bone and periodontal tissue heal faster and more efficiently in the maxilla compared with the mandible. Since stem cells are known to ...have a decisive influence on wound healing and tissue regeneration, the aim of this study was to determine whether differences in proliferation and differentiation of periodontal ligament stem cells (PDLSC) from upper (u‐PDLSC) and lower jaw (l‐PDLSC) contribute to the enhanced wound healing in the maxilla.
Methods
u‐PDLSC and l‐PDLSC from the same donor were harvested from the periodontal ligament of extracted human maxillary and mandibular third molars. Cell differentiation potential was assessed by analyzing stem cell markers, proliferation rate, and multilineage differentiation among each other and bone marrow‐derived mesenchymal stem cells (MSC). Successful differentiation of PDLSC and MSC toward osteoblasts, adipocytes, and chondrocytes was analyzed via reverse transcriptase‐quantitative polymerase chain reaction and histochemical staining (Alizarin Red, Oil Red O, Toluidine Blue).
Results
u‐PDLSC and l‐PDLSC expressed the MSC‐markers CD73+, CD90+, and CD105+ and lacked expression of CD34− and CD45−. Proliferation was significantly higher in u‐PDLSC than in l‐PDLSC, regardless of the culture conditions. Osteogenic (ALP, RunX2, and osteocalcin) and chondrogenic (SOX9 and ACAN) related gene expression as well as staining intensities were significantly higher in u‐PDLSC than in l‐PDLSC. No difference in adipogenic differentiation was observed.
Conclusion
u‐PDLSC showed a significantly higher proliferative and differentiation potential than l‐PDLSC, offering a possible cell‐based explanation for the differences in periodontal wound healing efficacy between maxilla and mandible.
The emergence of multidrug resistant bacteria, especially biofilm‐associated Staphylococci, urgently requires novel antimicrobial agents. The antibacterial activity of ultrasmall gold nanoparticles ...(AuNPs) is tested against two gram positive: S. aureus and S. epidermidis and two gram negative: Escherichia coli and Pseudomonas aeruginosa strains. Ultrasmall AuNPs with core diameters of 0.8 and 1.4 nm and a triphenylphosphine‐monosulfonate shell (Au0.8MS and Au1.4MS) both have minimum inhibitory concentration (MIC) and minimum bactericidal concentration of 25 × 10−6m Au. Disc agar diffusion test demonstrates greater bactericidal activity of the Au0.8MS nanoparticles over Au1.4MS. In contrast, thiol‐stabilized AuNPs with a diameter of 1.9 nm (AuroVist) cause no significant toxicity in any of the bacterial strains. Ultrasmall AuNPs cause a near 5 log bacterial growth reduction in the first 5 h of exposure, and incomplete recovery after 21 h. Bacteria show marked membrane blebbing and lysis in biofilm‐associated bacteria treated with ultrasmall AuNP. Importantly, a twofold MIC dosage of Au0.8MS and Au1.4MS each cause around 80%–90% reduction in the viability of Staphylococci enveloped in biofilms. Altogether, this study demonstrates potential therapeutic activity of ultrasmall AuNPs as an effective treatment option against staphylococcal infections.
Ultrasmall phosphine‐capped gold nanoparticles (AuNPs) of 0.8 and 1.4 nm diameter are found strongly bacteriotoxic in planktonic and biofilm Staphylococci. A favorable toxicity profile in bacteria versus eukaryotic cells suggests, e.g., grafting of ultrasmall AuNPs onto implant surfaces to reduce implant infection and biofilm formation.
Calciprotein particles, colloidal complexes of calcium phosphate and plasma protein fetuin-A, have emerged as mediators of multiple biological effects attributed to phosphate. A new study postulates ...that circulating calciprotein particles, not phosphate, regulate the production of the major bone-derived phosphatonin, fibroblast growth factor-23. The signaling events coupling calciprotein particles sensing in bone to fibroblast growth factor-23 secretion remain to be established.
Human mesenchymal stem cells (hMSC) are adult stem cells with multipotent capacities. The ability of mesenchymal stem cells to differentiate into many cell types, as well as their high ex vivo ...expansion potential, makes these cells an attractive therapeutic tool for cell transplantation and tissue engineering. hMSC are thought to contribute to tissue regeneration, but the signals governing their mobilization, diapedesis into the bloodstream, and migration into the target tissue are largely unknown. Here we report that hepatocyte growth factor (HGF) and the cognate receptor HGFR/c‐met are expressed in hMSC, on both the RNA and the protein levels. The expression of HGF was downregulated by transforming growth factor beta. HGF stimulated chemotactic migration but not proliferation of hMSC. Therefore the HGF/c‐met signaling system may have an important role in hMSC recruitment sites of tissue regeneration. The controlled regulation of HGF/c‐met expression may be beneficial in tissue engineering and cell therapy employing hMSC.
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