Fetuin (alpha2-HS-glycoprotein) opsonizes cationic macrophagedeactivating molecules

Glycopolymeric Nanoparticles Enrich Less Immunogenic Protein Coronas, Reduce Mononuclear Phagocyte Clearance, and Improve Tumor Delivery Compared to PEGylated Nanoparticles

Nanoparticles (NPs) offer significant promise as drug delivery vehicles; however, their in vivo efficacy is often hindered by the formation of a protein corona (PC), which influences key physiological responses such as blood circulation time, biodistribution, cellular uptake, and intracellular localization. Understanding NP-PC interactions is crucial for optimizing NP design for biomedical applications. Traditional approaches have utilized hydrophilic polymer coatings like polyethylene glycol (PEG) to resist protein adsorption, but glycopolymer-coated nanoparticles have emerged as potential alternatives due to their biocompatibility and ability to reduce the adsorption of highly immunogenic proteins. In this study, we synthesized and characterized glycopolymer-based poly[2-(diisopropylamino)ethyl methacrylate-b-poly(methacrylamidoglucopyranose) (PDPA-b-PMAG) NPs as an alternative to PEGylated NPs. We characterized the polymers using a range of techniques to establish their molecular weight and chemical composition. PMAG and PEG-based NPs showed equivalent physicochemical properties with sizes of ∼100 nm, spherical morphology, and neutral surface charges. We next assessed the magnitude of protein adsorption on both NPs and catalogued the identity of the adsorbed proteins using mass spectrometry-based techniques. The PMAG NPs were found to adsorb fewer proteins in vitro as well as fewer immunogenic proteins such as Immunoglobulins and Complement proteins. Flow cytometry and confocal microscopy were employed to examine cellular uptake in RAW 264.7 macrophages and MDA-MB-231 tumor cells, where PMAG NPs showed higher uptake into tumor cells over macrophages. In vivo studies in BALB/c mice with orthotopic 4T1 breast cancer xenografts showed that PMAG NPs exhibited prolonged circulation times and enhanced tumor accumulation compared to PEGylated NPs. The biodistribution analysis also revealed greater selectivity for tumor tissue over the liver for PMAG NPs. These findings highlight the potential of glycopolymeric NPs to improve tumor targeting and reduce macrophage uptake compared to PEGylated NPs, offering significant advancements in cancer nanomedicine and immunotherapy.

Influence of the polymer type of a microplastic challenge on the reaction of murine cells

Due to global pollution derived from plastic waste, the research on microplastics is of increasing public interest. Until now, most studies addressing the effect of microplastic particles on vertebrate cells have primarily utilized polystyrene particles (PS). Other studies on polymer microparticles made, e.g., of polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), or poly (ethylene terephthalate) (PET), cannot easily be directly compared to these PS studies, since the used microparticles differ widely in size and surface features. Here, effects caused by pristine microparticles of a narrow size range between 1 - 4 µm from selected conventional polymers including PS, PE, and PVC, were compared to those of particles made of polymers derived from biological sources like polylactic acid (PLA), and cellulose acetate (CA). The microparticles were used to investigate cellular uptake and assess cytotoxic effects on murine macrophages and epithelial cells. Despite differences in the particles' properties (e.g. ζ-potential and surface morphology), macrophages were able to ingest all tested particles, whereas epithelial cells ingested only the PS-based particles, which had a strong negative ζ-potential. Most importantly, none of the used model polymer particles exhibited significant short-time cytotoxicity, although the general effect of environmentally relevant microplastic particles on organisms requires further investigation.

Exploring the novel duo of Reticulocalbin, and Sideroflexin as future biomarker candidates for Exacerbated Chronic Obstructive Pulmonary Disease

BACKGROUND

COPD is a complex respiratory disorder with high morbidity and mortality rates. Even with the current conventional diagnostic methods, including circulating inflammatory biomarkers, underdiagnosis rates in COPD remain as high as 70%. Our study was a comparative cross-sectional study that aimed to address the diagnostic challenges by identifying future biomarker candidates in COPD variants.

METHODS

This study used a label-free plasma proteomics approach that combined mass spectrometric data with bioinformatics to shed light on the functional roles of differentially expressed proteins in the COPD lung microenvironment. The predictive capacity of the screened proteins was assessed using Receiver Operating Characteristic (ROC) curves, with Western blot analysis validating protein expression patterns in an independent cohort.

RESULTS

Our study identified three DEPs-reticulocalbin-1, sideroflexin-4, and liprinα-3 that consistently exhibited altered expression in COPD exacerbation. ROC analysis indicated strong predictive potential, with AUC values of 0.908, 0.715, and 0.856 for RCN1, SFXN4, and LIPα-3, respectively. Validation through Western blot analysis confirmed their expression patterns in an independent validation cohort.

CONCLUSIONS

Our study discovered a novel duo of proteins reticulocalbin-1, and sideroflexin-4 that showed potential as valuable future biomarkers for the diagnosis and clinical management of COPD exacerbations.

Fetuin-A adsorption to tunable polydimethylsiloxane and subsequent macrophage response

Surface modifications can be applied to biomaterials to alter the various surface properties that influence protein-material interactions and the cellular response. The plasma protein fetuin-A has been found to adsorb to many biomaterials but details of its interactions with polydimethylsiloxane (PDMS) and roles in regulating the immune response are not clear. Here, PDMS modifications are achieved by altering the ratio of PDMS formulations to control elastic modulus, and by coating PDMS with polydopamine (PDA) to attach fetuin-A. Surface characterization confirmed that altering the PDMS formulation changed the elastic modulus without affecting surface wetting properties. Surface roughness was measured using atomic force microscopy and surface chemistry was determined using X-ray photoelectron spectroscopy, with only minor changes detected on the softest samples. PDA deposition on PDMS was confirmed and contact angle measurements demonstrated an increase in hydrophilicity. Fetuin-A adsorption was influenced by the PDMS formulations, adsorption changed in a competitive plasma environment, and PDA was able to immobilize the greatest amount of fetuin-A. The inflammatory effects of fetuin-A were investigated, and data suggests that the elastic modulus influences cytokine secretion from macrophages at certain timepoints, a result likely due to varied protein amounts and orientations/conformations in response to material stiffness. The addition of a PDA layer demonstrated the potentially cytokine mitigating effect upon fetuin-A immobilization when compared to unmodified PDMS samples. The results provide new insight into the interactions of fetuin-A with PDMS and PDA, and the potential immune regulatory properties of fetuin-A modified materials.

Could a Non-Cellular Molecular Interactome in the Blood Circulation Influence Pathogens' Infectivity?

We advance the notion that much like artificial nanoparticles, relatively more complex biological entities with nanometric dimensions such as pathogens (viruses, bacteria, and other microorganisms) may also acquire a biomolecular corona upon entering the blood circulation of an organism. We view this biomolecular corona as a component of a much broader non-cellular blood interactome that can be highly specific to the organism, akin to components of the innate immune response to an invading pathogen. We review published supporting data and generalize these notions from artificial nanoparticles to viruses and bacteria. Characterization of the non-cellular blood interactome of an organism may help explain apparent differences in the susceptibility to pathogens among individuals. The non-cellular blood interactome is a candidate therapeutic target to treat infectious and non-infectious conditions.

Tissue and plasma proteomic profiling indicates AHSG as a potential biomarker for ascending thoracic aortic aneurysms

BACKGROUND

Thoracic Aortic Aneurysms (TAAs) develop asymptomatically and are characterized by dilatation of the aorta. This is considered a life-threatening vascular disorder due to the risk of aortic dissection and rupture. There is an urgent need to identify blood-borne biomarkers for the early detection of TAA. The goal of the present study was to identify potential protein biomarkers associated with TAAs, using proteomic analysis of aortic tissue and plasma samples.

METHODS

Extracted proteins from 14 aneurysmal and 12 non-aneurysmal thoracic aortic tissue specimens as well as plasma samples from six TAA patients collected pre-and postoperatively and six healthy controls (HC), were analyzed by liquid chromatography-tandem mass spectrometry. Proteomic data were further processed and following filtering criteria, one protein was selected for verification and validation in a larger cohort of patients and controls using a targeted quantitative proteomic approach and enzyme-linked immunosorbent assay, respectively.

RESULTS

A total of 1593 and 363 differentially expressed proteins were identified in tissue and plasma samples, respectively. Pathway enrichment analysis on the differentially expressed proteins revealed a number of dysregulated molecular pathways that might be implicated in aneurysm pathology including complement and coagulation cascades, focal adhesion, and extracellular matrix receptor interaction pathways. Alpha-2-HS glycoprotein (AHSG) was selected for further verification in 36 TAA and 21 HC plasma samples using targeted quantitative proteomic approach. The results showed a significantly decreased concentration of AHSG (p = 0.0002) in the preoperative plasma samples compared with HC samples. Further analyses using a larger validation dataset revealed that AHSG protein levels were significantly lower (p = 0.03) compared with HC. Logistic regression analysis on the validation dataset revealed males, advanced age, hypertension and hyperlipidaemia as significant risk factors for TAA.

CONCLUSION

AHSG concentrations distinguish plasma samples derived from TAA patients and controls. The findings of this study suggest that AHSG may be a potential biomarker for TAA that could lead to better diagnostic capabilities.

Facile fabrication of hierarchically nanostructured gold electrode for bio-electrochemical applications

Nanoporous gold (NPG) is one of the most extensively investigated nanomaterials owing to its tunable pore size, ease of surface modification, and range of applications from catalysis, actuation, and molecular release to the development of electrochemical sensors. In an effort to improve the usefulness of NPG, a simple and robust method for the fabrication of hierarchical and bimodal nanoporous gold electrodes (hb-NPG) containing both macro-and mesopores is reported using electrochemical alloying and dealloying processes to engineer a bicontinuous solid/void morphology. Scanning electron microscopy (color SEM) images depict the hierarchical pore structure created after the multistep synthesis with an ensemble of tiny pores below 100 nm in size located in ligaments spanning larger pores of several hundred nanometers. Smaller-sized pores are exploited for surface modification, and the network of larger pores aids in molecular transport. Cyclic voltammetry (CV) was used to compare the electrochemically active surface area of the hierarchical bimodal structure with that of the regular unimodal NPG with an emphasis on the critical role of both dealloying and annealing in creating the desired structure. The adsorption of different proteins was followed using UV-vis absorbance measurements of solution depletion revealing the high loading capacity of hb-NPG. The surface coverage of lipoic acid on the hb-NPG was analyzed using thermogravimetric analysis (TGA) and reductive desorption. The roughness factor determinations suggest that the fabricated hb-NPG electrode has tremendous potential for biosensor development by changing the scaling relations between volume and surface area which may lead to improved analytical performance. We have chosen to take advantage of the surface architectures of hb-NPG due to the presence of a large specific surface area for functionalization and rapid transport pathways for faster response. It is shown that the hb-NPG electrode has a higher sensitivity for the amperometric detection of glucose than does an NPG electrode of the same geometric surface area.

Effects of berberine hydrochloride on immune response in the crab Charybdis japonica

Berberine hydrochloride is the main effective component of Coptis spp. used in Chinese herbal medicine and its underlying molecular mechanisms, responsible for inducing effects in crustacean species, are not fully understood. In this study, the molecular response of the crab Charybdis japonica to berberine hydrochloride exposure was studied using transcriptome sequencing. The survival rate, gene expression and activities of several immune enzymes were measured after berberine hydrochloride treatments, with or without injection of the pathogenic bacterium Aeromonas hydrophila. A total of 962 differentially expressed genes (464 up-regulated and 498 down-regulated) were observed during exposure to 100 mg/L of berberine hydrochloride and in the control group after 48 h. Enrichment analysis revealed that these genes are involved in metabolism, cellular processes, signal transduction and immune functions, indicating that exposure to berberine hydrochloride activated the immune complement system. This bioactive compound simultaneously activated fibrinogen beta (FGB), fibrinogen alpha (FGA), alpha-2-macroglobulin (A2M), kininogen (KNG), fibrinogen gamma chain (FGB), alpha-2-HS-glycoprotein (AHSG), caspase-8 (CASP8), cathepsin L (CTSL), adenylate cyclase 3 (Adcy3) and MMP1. Its action could significantly increase the survival rate of the crabs injected with A. hydrophila and promote the activity of LZM, Caspas8, FGA, ACP and AKP in the hepatopancreas. When A. hydrophila was added, the neutralization of 300 mg/L berberine hydrochloride maximized the activities of Caspas8, LZM, ACP and AKP. Our results provide a new understanding of the potential effects of berberine hydrochloride on the immune system mechanisms in crustaceans.

Separation of Glycoproteins Based on Sugar Chains Using Novel Stationary Phases Modified with Poly(ethylene glycol)-Conjugated Boronic-Acid Derivatives

Boronic acid (BA) reversibly complexes with the diol structure. BA derivatives separate glycoproteins based on the differences in the sugar chains. Separation typically occurs under basic conditions, which does not guarantee the structural stability of glycoproteins. Here, 5-boronopicolinic acid (BPA) is used to prepare silica-gel based columns with poly(ethylene glycol) (PEG) as a linker to suppress nonselective adsorption and poly(ethylene imine) (PEI) as a scaffold to increase the BPA moiety density. High-performance liquid chromatography (HPLC) using only aqueous buffer solutions without organic solvents demonstrates the selective retention ability of the BPA columns for glycoproteins. BPA interacts with the diols in the sugar chains but not the proteins. In an evaluation for N-glycans, the BPA columns show a higher retention ability toward high mannose type and a lower affinity to N-acetylneuraminic acid (Neu5Ac). Finally, a pair of glycoproteins, fetuin and asialofetuin, are selectively separated due to the presence of Neu5Ac on the nonreducing end.

Selective Enrichment of Sialylglycopeptides Enabled by Click Chemistry and Dynamic Covalent Exchange

Despite the important roles of protein sialylation in biological processes such as cellular interaction and cancer progression, simple and effective methods for the analysis of intact sialylglycopeptides (SGPs) are still limited. Analyses of low-abundance SGPs typically require efficient enrichment prior to comprehensive liquid chromatography-mass spectrometry (LC-MS)-based analysis. Here, a novel workflow combining mild periodate oxidation, hydrazide chemistry, copper-catalyzed azide/alkyne cycloaddition (CuAAC) click chemistry, and dynamic covalent exchange has been developed for selective enrichment of SGPs. The intact SGPs could be separated easily from protein tryptic digests, and the signature ions were produced during LC-MS/MS for unambiguous identification. The structure of the signature ions and corresponding dynamic covalent exchange were confirmed by using an isotopic reagent. Under the optimized condition, over 70% enrichment efficiency of SGPs was achieved using bovine fetuin digests, and the method was successfully applied to complex biological samples, such as a mouse lung tissue extract. The high enrichment efficiency, good reproducibility, and easily adopted procedure without the need to generate specialized materials make this method a promising tool for broad applications in SGP analysis.

Tissue chaperoning—the expanded functions of fetuin-A beyond inhibition of systemic calcification

Traditionally, fetuin-A embodies the prototype anti-calcification protein in the blood, preventing cardiovascular calcification. Low serum fetuin-A is generally associated with mineralization dysbalance and enhanced mortality in end stage renal disease. Recent evidence indicates that fetuin-A is a crucial factor moderating tissue inflammation and fibrosis, as well as a systemic indicator of acute inflammatory disease. Here, the expanded function of fetuin-A is discussed in the context of mineralization and inflammation biology. Unbalanced depletion of fetuin-A in this context may be the critical event, triggering a vicious cycle of progressive calcification, inflammation, and tissue injury. Hence, we designate fetuin-A as tissue chaperone and propose the potential use of exogenous fetuin-A as prophylactic agent or emergency treatment in conditions that are associated with acute depletion of endogenous protein.

Can Fetuin A Be Utilized in the Evaluation of Elderly Patients with Acute Myocardial Infarction?

BACKGROUND

Lower baseline Fetuin-A (FA) is associated with left ventricular remodeling and cardiovascular death (CVD) at 4 months after acute myocardial infarction (AMI). However, the association between FA levels, incomplete ST segment resolution (STR) following primary percutaneous coronary intervention (PCI) and early mortality in AMI has not been previously studied.

METHODS

We enrolled 100 patients with AMI, which we divided in two groups: 21 patients who suffered sudden cardiac death (SCD) in the first 7 days after PCI and 79 controls. We measured FA, NT-proBNP and troponin levels and correlated them with the occurrence of death in the first week after revascularization. We also tested the cut-off value of FA to determine STR at 90 min after PCI.

RESULTS

SCD was most frequently caused by pump failure (n = 10, 47.6%) and ventricular arrhythmias (n = 9, 42.5%). Plasma FA levels correlated with NT-proBNP values (r = -0.47, p = 0.04) and were significantly lower in patients presenting SCD (115 (95-175) vs. 180 (105-250) ng/mL, p = 0.03). Among all three biomarkers, FA was the only one associated with incomplete STR after PCI on the multivariate logistic regression (cut-off value of 175 ng/mL, Se = 74%, Sp = 61.1%). Death rate was highest (n = 16/55, 30%) in patients with FA levels below the cut-off value of 175 ng/mL.

CONCLUSION

Lower FA is associated with higher early mortality and incomplete STR after primary percutaneous revascularization in patients with AMI. Measurement of FA levels in addition to NT-proBNP, troponin and STR might enable more accurate identification of high-risk patients.

Endogenous Regulation and Pharmacological Modulation of Sepsis-Induced HMGB1 Release and Action: An Updated Review

Sepsis remains a common cause of death in intensive care units, accounting for approximately 20% of total deaths worldwide. Its pathogenesis is partly attributable to dysregulated inflammatory responses to bacterial endotoxins (such as lipopolysaccharide, LPS), which stimulate innate immune cells to sequentially release early cytokines (such as tumor necrosis factor (TNF) and interferons (IFNs)) and late mediators (such as high-mobility group box 1, HMGB1). Despite difficulties in translating mechanistic insights into effective therapies, an improved understanding of the complex mechanisms underlying the pathogenesis of sepsis is still urgently needed. Here, we review recent progress in elucidating the intricate mechanisms underlying the regulation of HMGB1 release and action, and propose a few potential therapeutic candidates for future clinical investigations.

Effect of amino acid composition of elastin-like polypeptide nanoparticles on nonspecific protein adsorption, macrophage cell viability and phagocytosis

Development of elastin-like polypeptide (ELP) biomaterials is widespread, but information critical for clinical deployment is limited, with biocompatibility studies focused on a narrow cross-section of ELP sequences. Macrophages can impair biomaterial systems by degrading or isolating the biomaterial and by activating additional immune functions. Their phagocytic response will reveal early immune biocompatibility of ELP nanoparticles (NPs). This study examines that response, induced by the adsorbed protein corona, as a function of ELP guest amino acid, chain length and NP diameter. The breadth of proteins adsorbed to ELP NPs varied, with valine-containing ELP NPs adsorbing fewer types of proteins than leucine-containing constructs. Particle diameter was also a factor, with smaller leucine-containing ELP NPs adsorbing the broadest range of proteins. Macrophage viability was unaffected by the ELP NPs, and their phagocytic capabilities were unimpeded except when incubated with a 500 nm valine-containing 40-mer. This NP significantly decreased the phagocytic capacity of macrophages relative to the control and to a corresponding 500 nm leucine-containing 40-mer. NP size and the proportion of opsonin to dysopsonin proteins likely influenced this outcome. These results suggest that certain combinations of ELP sequence and particle size can result in an adsorbed protein corona, which may hinder macrophage function.

Is fetuin-A a biomarker of dialysis access dysfunction?

BACKGROUND

The arteriovenous (AV) access function of hemodialysis (HD) patients can be impaired by afferent artery stiffness due to preexisting microcalcification and by venous stenosis secondary to neointimal hyperplasia in whose development participates an upregulated local inflammatory process. Fetuin-A is a circulating potent inhibitor of vascular calcification and plays an important anti-inflammatory role. The aims of this prospective study were to investigate the relationship between baseline serum fetuin-A levels and: blood flow (Q_A) values at baseline, AV access failure (thrombosis or intervention for stenosis) during follow-up and primary unassisted AV access patency.

METHODS

We measured baseline serum fetuin-A levels and Q_A values of the AV access in 64 HD patients under routine Q_A surveillance for stenosis. Patients were classified into tertiles according to their baseline fetuin-A levels (g/L): <0.5 (tertile-1), 0.5-1.20 (tertile-2), and >1.20 (tertile-3).

RESULTS

Fetuin-A was positively correlated with Q_A (Spearman coefficient = 0.311, p = 0.012). Fourteen patients (21.9%) underwent AV access failure and they had lower fetuin-A (0.59 ± 0.32 g/L) and lower Q_A (739.4 ± 438.8 mL/min) values at baseline compared with the remaining patients (1.05 ± 0.65 g/L and 1273.0 ± 596.3 mL/min, respectively) (p = 0.027 and p < 0.001, respectively). The AV access failure rate was highest (34.8%) in tertile-1 (lowest fetuin-A level). Unadjusted Cox regression analysis showed a decrease in the risk of AV access patency loss by increasing fetuin-A concentration (hazard ratio 0.395 (95% confidence interval: 1.42-1.69), p = 0.044) but it was not confirmed in the adjusted model, although the hazard ratio was low (0.523). Kaplan-Meier analysis showed that patients in tertile-3 (highest fetuin-A concentration) had the highest primary unassisted AV access patency (λ² = 4.68, p = 0.030, log-rank test).

CONCLUSION

If our results are confirmed in further studies, fetuin-A could be used as a circulating biomarker to identify HD patients at greater risk for AV access dysfunction, who would benefit from much closer dialysis access surveillance.

Biophysical and Biochemical Comparison of Extracellular Vesicles Produced by Infective and Non-Infective Stages of Trypanosoma cruzi

Extracellular vesicles (EVs) are small lipid vesicles released by either any prokaryotic or eukaryotic cell, or both, with a biological role in cell-to-cell communication. In this work, we characterize the proteomes and nanomechanical properties of EVs released by tissue-culture cell-derived trypomastigotes (mammalian infective stage; (TCT)) and epimastigotes (insect stage; (E)) of Trypanosoma cruzi, the etiologic agent of Chagas disease. EVs of each stage were isolated by differential centrifugation and analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS), dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), electron microscopy and atomic force microscopy (AFM). Measurements of zeta-potential were also included. Results show marked differences in the surface molecular cargos of EVs between both stages, with a noteworthy expansion of all groups of trans-sialidase proteins in trypomastigote's EVs. In contrast, chromosomal locations of trans-sialidases of EVs of epimastigotes were dramatically reduced and restricted to subtelomeric regions, indicating a possible regulatable expression of these proteins between both stages of the parasite. Regarding mechanical properties, EVs of trypomastigotes showed higher adhesion compared to the EVs of epimastigotes. These findings demonstrate the remarkable surface remodeling throughout the life cycle of T. cruzi, which shapes the physicochemical composition of the extracellular vesicles and could have an impact in the ability of these vesicles to participate in cell communication in completely different niches of infection.

Biomaterials Regulating Bone Hematoma for Osteogenesis

Blood coagulation in tissue healing not only prevents blood loss, but also forms a natural scaffold for tissue repair and regeneration. As blood clot formation is the initial and foremost phase upon bone injury, and the quality of blood clot (hematoma) orchestrates the following inflammatory and cellular processes as well as the subsequent callus formation and bone remodeling process. Inspired by the natural healing hematoma, tissue-engineered biomimic scaffold/hydrogels and blood prefabrication strategies attract significant interests in developing functional bone substitutes. The alteration of the fracture hematoma ca significantly accelerate or impair the overall bone healing process. This review summarizes the impact of biomaterials on blood coagulation and provides evidence on fibrin network structure, growth factors, and biomolecules that contribute to bone healing within the hematoma. The aim is to provide insights into the development of novel implant and bone biomaterials for enhanced osteogenesis. Advances in the understanding of biomaterial characteristics (e.g., morphology, chemistry, wettability, and protein adsorption) and their effect on hematoma properties are highlighted. Emphasizing the importance of the initial healing phase of the hematoma endows the design of advanced biomaterials with the desired regulatory properties for optimal coagulation and hematoma properties, thereby facilitating enhanced osteogenesis and ideal therapeutic effects.

Effects of fetuin-A with diverse functions and multiple mechanisms on human health

Fetuin-A (Alfa 2-Heremans-Schmid) is a glycoprotein that is mainly synthesized by hepatocytes and then released into the bloodstream. While fetuin-A, a multifunctional protein, has inhibitory effects on health in the processes of calcification, mineralization, coronary artery calcification (CAC), and kidney stone formation by various mechanisms, it has such stimulatory effects as obesity, diabetes, and tumor progression processes. Fetuin-A produces these effects on the organism mainly by playing a role in the secretion levels of some inflammatory cytokines and exosomes, preventing unwanted calcification, inhibiting the autophosphorylation of tyrosine kinase, suppressing the release of adiponectin and peroxisome proliferator-activated receptor-γ (PPARγ), activating the toll-like receptor 4 (TLR-4), triggering the phosphatidylinositol 3 (PI3) kinase/Akt signaling pathway and cell proliferation, and mimicking the transforming growth factor-beta (TGF-β) receptor. In the present review, fetuin-A was examined in a wide perspective from the structure and release of fetuin-A to its effects on health.

An Overview of the Pathophysiology of Vascular Calcification in Chronic Kidney Disease

Abnormalities of calcium–phosphate balance, with subsequent bone metabolism disorders, are among the key and earliest features of chronic kidney disease (CKD). Recently, another consequence of these abnormalities was brought to light—namely, vascular calcification. Most studies performed in patients on dialysis suggest that their vascular calcification is more advanced than that seen in the general population. Furthermore, the progression of vessel wall mineralization is much more dynamic in patients with CKD.

Apart from the commonly assessed factors that promote vascular calcification, such as age, duration of dialysis, or poor control of calcium–phosphate status, several other factors have recently been identified. In the spectrum of substances involved in the regulation of the process of soft-tissue calcification, the most extensively studied in the nephrology literature are bone morphogenetic protein 7, osteoprotegerin, matrix Gla protein, fetuin-A, and the phosphatonins. Better understanding of the mechanisms underlying excess vascular mineralization have led to the development of promising new therapies.

Catabolism of biogenic amines in Pseudomonas species

Biogenic amines (BAs; 2-phenylethylamine, tyramine, dopamine, epinephrine, norepinephrine, octopamine, histamine, tryptamine, serotonin, agmatine, cadaverine, putrescine, spermidine, spermine and certain aliphatic amines) are widely distributed organic molecules that play basic physiological functions in animals, plants and microorganisms. Pseudomonas species can grow in media containing different BAs as carbon and energy sources, a reason why these bacteria are excellent models for studying such catabolic pathways. In this review, we analyse most of the routes used by different species of Pseudomonas (P. putida, P. aeruginosa, P. entomophila and P. fluorescens) to degrade BAs. Analysis of these pathways has led to the identification of a huge number of genes, catabolic enzymes, transport systems and regulators, as well as to understanding of their hierarchy and functional evolution. Knowledge of these pathways has allowed the design and collection of genetically manipulated microbes useful for eliminating BAs from different sources, highlighting the biotechnological applications of these studies.

Surface roughness influences the protein corona formation of glycosylated nanoparticles and alter their cellular uptake

Recently the role of protein absorption in nanoparticle drug delivery has gathered significant attention as the protein corona can significantly decide on the fate of nanoparticles in the body. Although it is known that the surface chemistry will significantly influence the amount and type of bound protein, there is little known about the effect of surface roughness and surface topography on the interaction. In this work, we show how patchy nanoparticles can noticeably reduce the adsorption of proteins compared to spherical nanoparticles with a smooth surface as demonstrated using six ABC triblock terpolymers based on glucose, mannose and galactose. To obtain patchy nanoparticles, poly(2-d-sugar ethyl acrylate)-b-poly (n-butyl acrylate)-b-poly(4-vinyl pyridine) (PSugEA-b-PBuA-b-P4VP) was prepared by reversible addition-fragmentation chain-transfer (RAFT) polymerization and assembled into nanoparticles with a patch-like appearance and a hydrodynamic diameter of around 130-160 nm. As control, smooth nanoparticles were prepared from poly(2-d-sugar ethyl acrylate)-b-poly (n-butyl acrylate)-b-polystyrene (PSugEA-b-PBuA-b-PS). The patchy nanoparticles displayed significantly reduced protein absorption when exposed to serum-supplemented cell culture media, as observed using dynamic light scattering. The smooth particles, however, supported the formation of a large protein corona. Additionally, an enrichment of haemoglobin was observed in the corona compared to the serum protein in solution. The amount of albumin on the surface was observed to be dependent on the type of sugar with glucose resulting in the highest absorption. The protein corona led to cellular uptake that was unrelated to the underlying sugar, which was supposed to help targeting specific cell lines. This example demonstrated how the protein corona can override any attempts to target receptor expressing cells.

The Role of Adipose Tissue and Adipokines in Sepsis: Inflammatory and Metabolic Considerations, and the Obesity Paradox

PURPOSE

Sepsis has become a global health problem with rising incidence and high mortality, creating a substantial social and economic burden. Early diagnosis and treatment can improve outcome, but reliable sepsis biomarkers are lacking. This review summarizes current evidence of the pathophysiological mechanisms linking adipose tissue to sepsis and presents experimental and clinical data on adipokines and sepsis along with important insights into the obesity paradox in sepsis survival.

RECENT FINDINGS

Sepsis is characterized by significant alterations in circulating cytokines and adipokines, biologically active molecules produced by the adipose tissue, being implicated in metabolic and inflammatory processes. Although data are inconclusive regarding classic adipokines such as leptin and adiponectin, recent evidence have highlighted the striking elevation of resistin and visfatin in critical illness and sepsis as well as their association with sepsis severity and outcomes. Given that inflammatory and metabolic pathways are involved in sepsis, studying adipokines presents an attractive, innovative, and promising research field that may provide more powerful diagnostic and prognostic biomarkers as well as novel therapeutic targets, empowering the therapeutic armamentarium for sepsis management in order to improve survival.

Pathophysiological Implication of Fetuin-A Glycoprotein in the Development of Metabolic Disorders: A Concise Review

Alpha 2-Heremans-Schmid glycoprotein, also known as fetuin-A (Fet-A), is a multifunctional plasma glycoprotein that has been identified in both animal and human beings. The protein is a hepatokine predominantly synthesized in the liver, which is considered as an important component of diverse normal and pathological processes, including bone metabolism regulation, vascular calcification, insulin resistance, and protease activity control. Epidemiological studies have already consistently demonstrated significant elevated circulating Fet-A in the course of obesity and related complications, such as type 2 diabetes mellitus, metabolic syndrome, and nonalcoholic fatty liver disorder (NAFLD). Moreover, Fet-A has been strongly correlated with many parameters related to metabolic homeostasis dysregulation, such as insulin sensitivity, glucose tolerance, circulating lipid levels (non-esterified free fatty acids and triglycerides), and circulating levels of both pro- and anti-inflammatory factors (C-reactive protein, tumor necrosis factor-α (TNF-α), and interleukin (IL)-6). Metabolic-interfering effects of Fet-A have thus been shown to highly exacerbate insulin resistance (IR) through blocking insulin-stimulated glucose transporter 4 (GLUT-4) translocation and protein kinase B (Akt) activation. Furthermore, the protein appeared to interfere with downstream phosphorylation events in insulin receptor and insulin receptor substrate signaling. The emerging importance of Fet-A for both diagnosis and therapeutics has therefore come to the attention of researchers and the pharmaceutical industry, in the prospect of developing new therapeutic strategies and diagnosis methods for metabolic disorders.

Interplay of protein corona and immune cells controls blood residency of liposomes

In vivo liposomes, like other types of nanoparticles, acquire a totally new 'biological identity' due to the formation of a biomolecular coating known as the protein corona that depends on and modifies the liposomes' synthetic identity. The liposome-protein corona is a dynamic interface that regulates the interaction of liposomes with the physiological environment. Here we show that the biological identity of liposomes is clearly linked to their sequestration from peripheral blood mononuclear cells (PBMCs) of healthy donors that ultimately leads to removal from the bloodstream. Pre-coating liposomes with an artificial corona made of human plasma proteins drastically reduces capture by circulating leukocytes in whole blood and may be an effective strategy to enable prolonged circulation in vivo. We conclude with a critical assessment of the key concepts of liposome technology that need to be reviewed for its definitive clinical translation.

The role of intra-articular administration of Fetuin-A in post-traumatic knee osteoarthritis: an experimental study in a rat model

 Background

The purpose of this study is to investigate the possible attenuating role of the intra-articular administration of Fetuin-A in post-traumatic secondary osteoarthritis in rats, and also its effect on the systematic levels of interleukins (ILs)-2,4,7, bone morphogenetic proteins (BMPs) 2, 4, 7, C-Reactive Protein (CRP) and Fetuin-A.

Methods

Thirty male Sprague Dawley rats were separated in two groups where post-traumatic osteoarthritis was induced surgically by Anterior Cruciate Ligament Transection and the transection of the Medial Collateral Ligament of the right knee. In the Control Group, only the surgical intervention took place. In Fetuin Group, along with the induction of osteoarthritis, a single dose of bovine fetuin was administrated intra-articularly, intra-operatively. Both groups were examined for 8 weeks. The levels of interleukins, bone morphogenetic proteins, Fetuin-A and C-Reactive Protein were evaluated by ELISA of peripheral blood in three time periods: preoperatively, 5 and 8 weeks post-operatively. Osteoarthritic lesions of the knee were classified according to the Osteoarthritis Research Society International Grading System and the Modified Mankin Score, by histologic examination.

Results

IL-2 levels were significantly decreased in the Fetuin Group. No statistical difference was signed on the levels of IL-7, BMP-2,4,7 and Fetuin-A between the two groups. CRP levels were significantly increased in the Fetuin Group in 5 weeks of the experiment. Fetuin Group signed better scores according to the OARSI classification system and Modified Mankin Score, without any statistical significance.

Conclusions

Intra-articular administration of Fetuin-A restrictively affected the progression of post-traumatic arthritis in rats, as only the levels of IL-2 were decreased as well as limited osteoarthritic lesions were observed on the Fetuin Group.

The Growth of Preantral Follicles and the Impact of Different Supplementations and Circumstances: A Review Study with Focus on Bovine and Human Preantral Follicles

One of the most important concerns cancer survivors face is fertility. Current treatment modalities often result in damage to the reproductive system. Different options have been proposed to preserve the fertility of affected women, and many attempts have been made to improve their chance of childbearing after therapy. Cryopreservation of ovarian tissue and follicles before the onset of cancer treatment and then either transplantation of ovarian tissue or culture of ovarian tissue and individual follicles in vitro is a commonly cited approach. Extensive research is being done to design an optimal condition for the culture of ovarian follicles. Improving follicle culture systems by understanding their actual growth needs might be a crucial step toward fertility preservation in cancer patients. This review article will try to provide a summary of the role of different factors and conditions on growth of human and bovine preantral follicles in vitro.

Targeted Measurements of O- and N-Glycopeptides Show That Proteins in High Density Lipoprotein Particles Are Enriched with Specific Glycosylation Compared to Plasma

High density lipoprotein (HDL) particles are believed to be protective due to their inverse correlation with the prevalence of cardiovascular diseases. However, recent studies show that in some conditions such as heart disease and diabetes, HDL particles can become dysfunctional. Great attention has been directed toward HDL particle composition because the relative abundances of HDL constituents determine HDL's functional properties. A key factor to consider when studying the structure and composition of plasma particles is the protein glycosylation. Here, we profile the O- and N-linked glycosylation of HDL associated-proteins including the truncated form of Apo CIII and their glycan heterogeneity in a site-specific manner. Apolipoprotein CIII, fetuin A, and alpha 1 antitrypsin are glycoproteins associated with lipoproteins and are implicated in many cardiovascular and other disease conditions. A targeted method (UHPLC-QQQ) was used to measure the glycoprotein concentrations and site-specific glycovariations of the proteins in human plasma and compared with HDL particles isolated from the same plasma samples. The proteins found in the plasma are differentially glycosylated compared to those isolated in HDL. The results of this study suggest that glycosylation may play a role in protein partitioning in the blood, with possible functional implications.

A single intraperitoneal injection of bovine fetuin-A attenuates bone resorption in a murine calvarial model of particle-induced osteolysis

Particle-induced osteolysis, which by definition is an aseptic inflammatory reaction to implant-derived wear debris eventually leading to local bone destruction, remains the major reason for long-term failure of orthopedic endoprostheses. Fetuin-A, a 66kDa glycoprotein with diverse functions, is found to be enriched in bone. Besides being an important inhibitor of ectopic calcification, it has been described to influence the production of mediators of inflammation. Furthermore, a regulatory role in bone metabolism has been assigned. In the present study, the influence of a single dose of bovine fetuin-A, intraperitoneally injected in mice subjected to particle-induced osteolysis of the calvaria, was analyzed. Twenty-eight male C57BL/6 mice, twelve weeks of age, were randomly divided into four groups. Groups 2 and 4 were subjected to ultra-high molecular weight polyethylene (UHMWPE) particles placed on their calvariae while groups 1 and 3 were sham-operated. Furthermore, groups 3 and 4 received a single intraperitoneal injection of 20mg bovine fetuin-A while groups 1 and 2 were treated with physiologic saline. After 14days calvarial bone was qualitatively and quantitatively assessed using microcomputed tomography (μCT) and histomorphometrical approaches. Application of fetuin-A led to a reduction of particle-induced osteolysis in terms of visible osteolytic lesions and eroded bone surface. The reduction of bone thickness and bone volume, as elicited by UHMWPE, was alleviated by fetuin-A. In conclusion, fetuin-A was found to exert an anti-resorptive effect on particle-induced osteolysis in-vivo. Thus, fetuin-A could play a potentially osteoprotective role in the treatment of bone metabolic disorders.

A novel fluorescent probe-based flow cytometric assay for mineral-containing nanoparticles in serum

Calciprotein particles, nanoscale aggregates of insoluble mineral and binding proteins, have emerged as potential mediators of phosphate toxicity in patients with Chronic Kidney Disease. Although existing immunochemical methods for their detection have provided compelling data, these approaches are indirect, lack specificity and are subject to a number of other technical and theoretical shortcomings. Here we have developed a rapid homogeneous fluorescent probe-based flow cytometric method for the detection and quantitation of individual mineral-containing nanoparticles in human and animal serum. This method allows the discrimination of membrane-bound from membrane-free particles and different mineral phases (amorphous vs. crystalline). Critically, the method has been optimised for use on a conventional instrument, without the need for manual hardware adjustments. Using this method, we demonstrate a consistency in findings across studies of Chronic Kidney Disease patients and commonly used uraemic animal models. These studies demonstrate that renal dysfunction is associated with the ripening of calciprotein particles to the crystalline state and reveal bone metabolism and dietary mineral as important modulators of circulating levels. Flow cytometric analysis of calciprotein particles may enhance our understanding of mineral handling in kidney disease and provide a novel indicator of therapeutic efficacy for interventions targeting Chronic Kidney Disease-Mineral Bone Disorder.

Kinetics of circulating fetuin-A may predict mortality independently from adiponectin, high molecular weight adiponectin and prognostic factors in critically ill patients with sepsis: A prospective study

PURPOSE

Fetuin-A and adiponectin, major hepatokine and adipokine respectively, have been implicated in systematic inflammation. Our aim was to jointly investigate whether kinetics of circulating fetuin-A, adiponectin and its isoform HMWA predict 28-day mortality in sepsis.

MATERIALS AND METHODS

In a prospective study, serum fetuin-A, adiponectin and HMWA were determined in 102 ICU patients fulfilling the diagnostic criteria of SEPSIS-3, at enrollment and one week after, and in 102 healthy controls matched on age and gender.

RESULTS

Serum fetuin-A was significantly lower in septic patients than controls (p<0.001). Among septic patients, those with septic shock and nonsurvivors presented lower fetuin-A, but higher adiponectin and HMWA compared to patients with sepsis and survivors respectively, both at baseline and day 7 (p<0.001). Fetuin-A exhibited negative correlations with APACHE II, CRP, procalcitonin, adiponectin and IL-6 but a positive one with albumin. Reduced fetuin-A as well as lower serum kinetics of fetuin-A (HR: 0.55, 95% C.I. 0.34-0.91, p=0.02), adiponectin but not HMWA were independently associated with 28-day mortality adjusting for age, gender, BMI, APACHE II, septic shock and laboratory biomarkers.

CONCLUSIONS

Circulating fetuin-A kinetics may be a prognostic biomarker in septic patients. More research is essential to elucidate fetuin-A's ontological role in sepsis pathophysiology.

Elucidation of the Role of 3-Hydroxy Fatty Acids in Cryptococcus-amoeba Interactions

We previously reported that 3-hydroxy fatty acids promoted the survival of cryptococcal cells when acted upon by amoebae. To expand on this, the current study sought to explain how these molecules may protect cells. Our data suggest that 3-hydroxy fatty acids may subvert the internalization of cryptococcal cells via suppression of the levels of a fetuin A-like amoebal protein, which may be important for enhancing phagocytosis. Additionally, we show that an acapsular strain (that is devoid of 3-hydroxy fatty acids) was protected against the effects of hydrogen peroxide when exogenous 3-hydroxy fatty acids were present, but not in the absence of 3-hydroxy fatty acids. A similar response profile was noted when a strain with a capsule was challenged with hydrogen peroxide. We also show that cryptococcal cells that naturally produce 3-hydroxy fatty acids were more resistant to the effects of amoebapore (an amoeba-specific hydrolytic enzyme), compared to cells that do not produce these molecules. Taken together, our findings suggest that 3-hydroxy fatty acids possess an anti-phagocytic activity that may be expressed when cells interact with macrophages. This may allow the yeast cells to evade immuno-processing.

Role of Pyridoxal 5'-Phosphate at the Titanium Implant Interface In Vivo: Increased Hemophilicity, Inactive Platelet Adhesion, and Osteointegration

Titanium is the most biocompatible inorganic biomaterial with a long history of use in orthopedic and dental implants. However, promoting rapid and effective bone formation and integration onto etched, rough TiO₂ surfaces has been a challenging topic. Here, 21 commercially available molecules are examined that met the following criteria: (1) contain phosphonic acid for stable immobilization onto TiO₂ surfaces and (2) have a molecular weight less than 500 Da for negligible coating thickness. Of these molecules, the surface immobilization of pyridoxal 5'-phosphate (PLP), an active form of vitamin B₆ , dramatically increases the hemophilic property of the surface and accelerated osteointegration in vivo. Analysis shows that PLP promotes surface binding of serum albumin and other plasma proteins by Schiff-base formations via its aldehyde group, providing a platform suitable for osteoblast adhesion. PLP also retards blood coagulation more than the widely used citric acid at the TiO₂ surface. As PLP is capable of maintaining an inactivated status of surface-adsorbed platelets, delayed coagulation at the implant-blood interface allows for sufficient supply of growth factors from blood plasma and migration of osteoblasts. The results suggest that PLP can be widely applicable as a biocompatible, effective coating compound to promote osteointegration of titanium-based implants.

Plasma fetuin-A/α2-HS-glycoprotein correlates negatively with inflammatory cytokines, chemokines and activation biomarkers in individuals with type-2 diabetes

Background

Fetuin-A/AHSH is a novel hepatokine that acts as a vascular calcification inhibitor and as an endogenous TLR-4 ligand. Fetuin-A may act as a positive or negative acute phase protein (APP) in disease conditions. The relationship between circulatory fetuin-A and inflammatory biomarkers in type-2 diabetes (T2D) remains controversial. Therefore, the purpose of this study was to determine the plasma fetuin-A levels in 53 T2D (BMI = 29.7 ± 4.5 kg/m²) and 72 non-diabetic individuals (BMI = 28.2 ± 5.8 kg/m²) using premixed 38-plex MAP human cytokine/chemokine magnetic bead immunoassays and the data (mean ± SEM) were statistically analyzed to determine Pearson’s correlation (r) between fetuin-A and detected analytes; P-values ≤0.05 were considered significant.

Results

The data show that plasma fetuin-A levels were comparable in both groups (P = 0.27) and in T2D individuals, fetuin-A associated negatively (P ≤ 0.05) with a large number of proinflammatory cytokines/chemokines and activation biomarkers including TNF-α, IFN-α2, IFN-γ, IL-1α, IL-1β, IL-1RA, IL-3, IL-4, IL-7, IL-9, IL-12p40/p70, IL-15, CCL-2, CCL-4, CCL-11, CCL-22, CXCL-8, CX3CL-1, EFF-2, EGF, G-CSF, GM-CSF, GRO, sCD40L, and VEGF. In non-diabetics, fetuin-A also correlated positively with certain T_H2 cytokines (IL-5, IL-13) and chemokines (CCL-3, CCL-5, CCL-7). Notably, in vitro fetuin-A production was significantly suppressed in HepG2 cells treated with TNF-α, IL-1β, and IFN-γ which supported the clinical findings of a negative association between fetuin A and inflammatory mediators.

Conclusions

The negative association between circulatory fetuin-A and systemic inflammatory mediators in T2D patients suggests that plasma fetuin-A may have predictive significance as a negative APP in metabolic disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-016-0171-y) contains supplementary material, which is available to authorized users.

Novel biomarkers predicting cardiac function after acute myocardial infarction

BACKGROUND

Measurement of biomarkers provides a cost-effective and widely available method to estimate cardiac dysfunction and clinical outcome of patients with acute myocardial infarction (AMI).

SOURCES OF DATA

PubMed entries with terms 'myocardial infarction' and the respective biomarker.

AREAS OF AGREEMENT

Cardiac troponins and natriuretic peptides are closely related to left ventricular dysfunction and the occurrence of adverse clinical events following AMI.

AREAS OF CONTENTION

The incremental value of novel biomarkers is controversial.

FUTURE DIRECTIONS

The combination of traditional and novel biomarkers might further improve risk stratification of patients with AMI.

SEARCH STRATEGY

We searched all entries on the PubMed database with the MeSH terms 'myocardial infarction' and 'cardiac troponins', 'natriuretic peptides', 'copeptin', galectin-3', 'corin', 'fetuin-A', 'adiponectin' and 'microRNA'.

Linker-Region Modified Derivatives of the Deoxyhypusine Synthase Inhibitor CNI-1493 Suppress HIV-1 Replication

The inhibition of cellular factors that are involved in viral replication may be an important alternative to the commonly used strategy of targeting viral enzymes. The guanylhydrazone CNI-1493, a potent inhibitor of the deoxyhypusine synthase (DHS), prevents the activation of the cellular factor eIF-5A and thereby suppresses HIV replication and a number of other diseases. Here, we report on the design, synthesis and biological evaluation of a series of CNI-1493 analogues. The sebacoyl linker in CNI-1493 was replaced by different alkyl or aryl dicarboxylic acids. Most of the tested derivatives suppress HIV-1 replication efficiently in a dose-dependent manner without showing toxic side effects. The unexpected antiviral activity of the rigid derivatives point to a second binding mode as previously assumed for CNI-1493. Moreover, the chemical stability of CNI-1493 was analysed, showing a successive hydrolysis of the imino bonds. By molecular dynamics simulations, the behaviour of the parent CNI-1493 in solution and its interactions with DHS were investigated.

The relationship of circulating fetuin-a with liver histology and biomarkers of systemic inflammation in nondiabetic subjects with nonalcoholic fatty liver disease

BACKGROUND/AIMS

Fetuin-A, a glycoprotein with anti-inflammatory properties, plays an important role in counter-regulating inflammatory responses. It has also been associated with insulin resistance and metabolic syndrome. We aimed to investigate circulating concentrations of fetuin-A and its possible association with hepatic and systemic inflammation in nondiabetic subjects with nonalcoholic fatty liver disease (NAFLD).

PATIENTS AND METHODS

We included 105 nondiabetic male subjects with NAFLD [nonalcoholic steatohepatitis (NASH, n = 86) and simple steatosis (SS, n = 19)]. Plasma levels of fetuin-A and markers of inflammation [high-sensitive C reactive protein (hsCRP), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and adiponectin] were measured by enzyme-linked immunosorbent assay method. Insulin sensitivity was determined by homeostasis model assessment of insulin resistance (HOMA-IR) index.

RESULTS

Fetuin-A was negatively correlated with age (r = -0.27, P = 0.006), however there was no association between fetuin-A and body mass index, waist circumference (WC), glucose, insulin, HOMA-IR, lipid parameters, and inflammatory markers. In addition, no significant association was observed between fetuin-A and histological findings including liver fibrosis.

CONCLUSION

This study demonstrated that plasma fetuin-A levels are not correlated with the hepatic histology and systemic markers of inflammation in nondiabetic subjects with NAFLD. Our data also suggested that age is significantly associated with fetuin-A in this clinically relevant condition.

Beneficiary effect of nanosizing ferric pyrophosphate as food fortificant in iron deficiency anemia: evaluation of bioavailability, toxicity and plasma biomarker

NP-Fe₄(P₂O₇)₃significantly improved hemoglobin level in iron-deficient rats and Fetuin-B showed differential biological response across NP doses through plasma proteomics.

Molecular mechanism and therapeutic modulation of high mobility group box 1 release and action: an updated review

High mobility group box 1 (HMGB1) is an evolutionarily conserved protein, and is constitutively expressed in virtually all types of cells. Infection and injury converge on common inflammatory responses that are mediated by HMGB1 secreted from immunologically activated immune cells or passively released from pathologically damaged cells. Herein we review the emerging molecular mechanisms underlying the regulation of pathogen-associated molecular patterns (PAMPs)-induced HMGB1 secretion, and summarize many HMGB1-targeting therapeutic strategies for the treatment of infection- and injury-elicited inflammatory diseases. It may well be possible to develop strategies that specifically attenuate damage-associated molecular patterns (DAMPs)-mediated inflammatory responses without compromising the PAMPs-mediated innate immunity for the clinical management of infection- and injury-elicited inflammatory diseases.

Intraperitoneal administration of fetuin-A attenuates D-galactosamine/lipopolysaccharide-induced liver failure in mouse

BACKGROUND

Fulminant hepatic failure (FHF) is a devastating syndrome, which sometimes results in death or liver transplantation, in which inflammation would aggravate the development of fetuin-A which would act as an anti-inflammatory factor and may be an available approach to attenuate FHF.

AIMS

The purpose of this study was to investigate the effects of fetuin-A on D-galactosamine/lipopolysaccharide (D-GalN/LPS)-induced liver failure in mice.

METHODS

A mouse model of FHF induced by D-GalN/LPS was established and fetuin-A was injected intraperitoneally prior to D-GalN/LPS treatment. At different time points after D-GalN/LPS intervention, serum TNF-α and IL-6 levels were measured by ELISA. Fetuin-A mRNA and protein expression in liver tissues was assessed by RT-PCR, Western blotting and immunohistochemical staining. Besides, an observation of liver tissue injury, the apoptosis of hepatocytes, was analyzed by TUNEL assay.

RESULTS

Expression of fetuin-A mRNA and protein in liver tissue were significantly and gradually decreased after D-GalN/LPS administration. A pre-intervention of exogenous fetuin-A significantly improved the liver function, decreased TNF-α and IL-6 expression in peripheral blood, and liver tissue inhibited hepatocyte apoptosis responded to D-GalN/LPS induction so as to decrease the mortality rates of FHF mouse. Meanwhile, fetuin-A was negatively correlated with the hepatic pathological score and TNF-α protein staining in FHF mouse.

CONCLUSIONS

An intraperitoneal injection of fetuin-A attenuates D-GalN/LPS-induced FHF in mice. Fetuin-A might be a protective agent of liver damage partly through inhibiting liver inflammatory response and hepatocyte apoptosis.

Potential role of Helicobacter pylori infection in nonalcoholic fatty liver disease

Accumulating evidence has implicated Helicobacter pylori (H. pylori) infection in extragastrointestinal diseases, including obesity, type 2 diabetes mellitus, cardiovascular disease, and liver disease. Recently, there has been a special focus on H. pylori infection as a risk factor for the development of nonalcoholic fatty liver disease (NAFLD). NAFLD is currently considered to be the most common liver disorder in western countries, and is rapidly becoming a serious threat to public health. The mechanisms of pathogenesis underlying NAFLD remain unclear at present and therapeutic options are limited. The growing awareness of the role of H. pylori in NAFLD is thus important to aid the development of novel intervention and prevention strategies, because the eradication of H. pylori is easy and much less expensive than long-term treatment of the other risk factors. H. pylori infection is involved in the pathogenesis of insulin resistance (IR), which is closely linked with NAFLD. It provides a new insight into the pathogenesis of NAFLD. This review probes the possible relationship between H. pylori and NAFLD, from the perspective of the potential mechanism of how H. pylori infection brings about IR and other aspects concerning this correlation.

Adventitial transduction of lentivirus-shRNA-VEGF-A in arteriovenous fistula reduces venous stenosis formation

Venous neointimal hyperplasia (VNH) causes hemodialysis vascular access failure. Here we tested whether VNH formation occurs in part due to local vessel hypoxia caused by surgical trauma to the vasa vasorum of the outflow vein at the time of arteriovenous fistula placement. Selective targeting of the adventitia of the outflow vein at the time of fistula creation was performed using a lentivirus-delivered small-hairpin RNA that inhibits VEGF-A expression. This resulted in significant increase in mean lumen vessel area, decreased media/adventitia area, and decreased constrictive remodeling with a significant increase in apoptosis (increase in caspase 3 activity and TUNEL staining) accompanied with decreased cellular proliferation and hypoxia-inducible factor-1α at the outflow vein. There was significant decrease in cells staining positive for α-smooth muscle actin (a myofibroblast marker) and VEGFR-1 expression with a decrease in MMP-2 and MMP-9. These results were confirmed in animals that were treated with humanized monoclonal antibody to VEGF-A with similar results. Since hypoxia can cause fibroblast to differentiate into myofibroblasts, we silenced VEGF-A gene expression in fibroblasts and subjected them to hypoxia. This decreased myofibroblast production, cellular proliferation, cell invasion, MMP-2 activity, and increased caspase 3. Thus, VEGF-A reduction at the time of arteriovenous fistula placement results in increased positive vascular remodeling.

Simvastatin reduces venous stenosis formation in a murine hemodialysis vascular access model

Venous neointimal hyperplasia (VNH) is responsible for hemodialysis vascular access malfunction. Here we tested whether VNH formation occurs, in part, due to vascular endothelial growth factor-A (VEGF-A) and matrix metalloproteinase (MMP)-9 gene expression causing adventitial fibroblast transdifferentiation to myofibroblasts (α-SMA-positive cells). These cells have increased proliferative and migratory capacity leading to VNH formation. Simvastatin was used to decrease VEGF-A and MMP-9 gene expression in our murine arteriovenous fistula model created by connecting the right carotid artery to the ipsilateral jugular vein. Compared to fistulae of vehicle-treated mice, the fistulae of simvastatin-treated mice had the expected decrease in VEGF-A and MMP-9 but also showed a significant reduction in MMP-2 expression with a significant decrease in VNH and a significant increase in the mean lumen vessel area. There was an increase in terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining, and decreases in α-SMA density, cell proliferation, and HIF-1α and hypoxyprobe staining. This latter result prompted us to determine the effect of simvastatin on fibroblasts subjected to hypoxia in vitro. Simvastatin-treated fibroblasts had a significant decrease in myofibroblast production along with decreased cellular proliferation, migration, and MMP-9 activity but increased caspase 3 activity suggesting increased apoptosis. Thus, simvastatin results in a significant reduction in VNH, with increase in mean lumen vessel area by decreasing VEGF-A/MMP-9 pathway activity.

Fetuin-A-containing calciprotein particles reduce mineral stress in the macrophage

The formation of fetuin-A-containing calciprotein particles (CPP) may facilitate the clearance of calcium phosphate nanocrystals from the extracellular fluid. These crystals may otherwise seed extra-osseous mineralization. Fetuin-A is a partially phosphorylated glycoprotein that plays a critical role in stabilizing these particles, inhibiting crystal growth and aggregation. CPP removal is thought to be predominantly mediated by cells of the reticuloendothelial system via type I and type II class A scavenger receptor (SR-AI/II). Naked calcium phosphate crystals are known to stimulate macrophages and other cell types in vitro, but little is known of the effect of CPP on these cells. We report here, for the first time, that CPP induce expression and secretion of tumour necrosis factor (TNF)-α, interleukin (IL)-1β in murine RAW 264.7 macrophages. Importantly, however, CPP induced significantly lower cytokine secretion than hydroxyapatite (HAP) crystals of equivalent size and calcium content. Furthermore, CPP only had a modest effect on macrophage viability and apoptosis, even at very high levels, compared to HAP crystals, which were strongly pro-apoptotic at much lower levels. Fetuin-A phosphorylation was found to modulate the effect of CPP on cytokine secretion and apoptosis, but not uptake via SR-AI/II. Prolonged exposure of macrophages to CPP was found to result in up-regulated expression of SR-AI/II. CPP formation may help protect against some of the pro-inflammatory and harmful effects of calcium phosphate nanocrystals, perhaps representing a natural defense system for calcium mineral stress. However, in pathological states where production exceeds clearance capacity, these particles may still stimulate pro-inflammatory and pro-apoptotic cascades in macrophages, which may be important in the pathogenesis of vascular calcification.

Serum levels of BMP-2, 4, 7 and AHSG in patients with degenerative joint disease requiring total arthroplasty of the hip and temporomandibular joints

To date, there is no objective or reliable means of assessing the severity of degenerative joint disease (DJD) and need for joint replacement surgery. Hence, it is difficult to know when an individual with DJD has reached a point where total arthroplasty is indicated. The purpose of the present study is to determine whether serum levels of Alpha-2 HS-glycoprotein (AHSG) as well as bone morphogenetic proteins (BMP-2, 4, 7) can be used to predict the presence of severe DJD of the hip and/or temporomandibular joint (TMJ) (specifically: joints that require replacement). A total of 30 patients scheduled for arthroplasty (diseased) (15 HIP, 15 TMJ) and 120 age-matched controls (healthy/non-diseased) were included. Blood samples were collected from all patients ≥8 weeks after the last arthroplasty. Concentrations of serum analytes were measured using enzyme-linked immunosorbent assays, and these were compared between the Diseased and Healthy groups, utilizing the Mann-Whitney U-test. Patients with disease had significantly higher levels of BMP-2 and BMP-4 and lower levels of AHSG in serum compared to non-diseased humans (p < 0.01). Higher levels of BMP-2, 4 and reduced levels of AHSG appear to characterize patients who have DJD that is severe enough to require total joint replacement. Perhaps measurements of these proteins can be used to make objective decisions regarding the need for total arthroplasty as opposed to the current subjective approaches.

Usefulness of fetuin-A and C-reactive protein concentrations for prediction of outcome in acute coronary syndromes (from the French Registry of Acute ST-Elevation Non-ST-Elevation Myocardial Infarction [FAST-MI])

Fetuin-A is a ubiquitous anti-inflammatory glycoprotein that counteracts proinflammatory cytokine production. Previous studies have shown that low fetuin-A concentration is associated with cardiovascular death and may play an important role in the prognosis of patients with acute coronary syndromes (ACS). The purpose of this study was to assess in large cohort of patients admitted for ACS the prognostic value of fetuin-A adjusted for C-reactive protein value (CRP) and Global Registry of Acute Coronary Events (GRACE) risk score. Plasma fetuin-A and CRP concentrations were measured on day 3 in 754 consecutive patients with ACS (mean age 66 ± 14 years, 404 with ST-segment elevation and 350 without ST-segment elevation) included in the French Registry of Acute ST-Elevation or Non-ST-Elevation Myocardial Infarction (FAST-MI), and these data were correlated to 1-year mortality. Plasma fetuin-A and CRP concentrations at admission averaged 95 ± 27 and 12 ± 16 mg/L, respectively. Overall, 1-year cardiovascular mortality was 10% (28 in-hospital deaths and 51 deaths after discharge), 17% in patients with low fetuin-A (less than the first tertile), 18% with high CRP (higher than the third tertile), and 23% in patients with low fetuin associated with high CRP (p <0.01). In contrast, patients with neither low fetuin-A nor high CRP had a low mortality rate (5%). Multivariate analysis adjusted for GRACE risk score showed that low fetuin-A and high CRP concentration remained associated with outcomes (odds ratio 2.28, 95% confidence interval 1.20 to 4.33). In conclusion, fetuin-A combined with CRP level is associated with cardiovascular death in patients with ACS.

CNI-1493 attenuates neuroinflammation and dopaminergic neurodegeneration in the acute MPTP mouse model of Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is associated with neurodegeneration of dopaminergic neurons in the substantia nigra. Neuroinflammatory processes have been shown to be a key component of this neurodegeneration and, as such, small molecule compounds which inhibit these inflammatory events are a critical research focus.

OBJECTIVE

CNI-1493 is an anti-inflammatory compound that strongly inhibits macrophages and also stimulates the cholinergic anti-inflammatory pathway. We have examined whether CNI-1493 has a neuroprotective effect in the acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD.

METHODS

CNI-1493 (8 mg/kg i.p.) or placebo administration was started 1 day before MPTP intoxication and repeated daily until sacrifice after MPTP intoxication. C57/Bl6 mice - either treated with CNI-1493 or with placebo - were injected intraperitoneally 4 times at 2-hour intervals with either 20 mg/kg MPTP-HCl or a corresponding volume of saline. Two or 7 days after the end of the MPTP intoxication, the animals were killed and their brains were processed for further analysis.

RESULTS

Administration of CNI-1493 markedly protected tyrosine hydroxylase-positive substantia nigra neurons against MPTP neurotoxicity. CNI-1493 treatment in the MPTP model was also accompanied by a profound reduction of activated microglia within the substantia nigra, as measured by ionized calcium-binding adapter molecule-1 staining.

CONCLUSIONS

These findings support that CNI-1493 could reduce the MPTP-induced toxicity likely by inhibition of neuroinflammatory responses. The neuroprotective effect of CNI-1493 suggests that CNI-1493 might be a valuable neuroprotective candidate in the future treatment of PD.