Over the last years, top-down (TD) MS has gained a remarkable space in proteomics, rapidly trespassing the limit between a promising approach and a solid, established technique. Several research ...groups worldwide have implemented TD analysis in their routine work on proteomics, deriving structural information on proteins with the level of accuracy that is impossible to achieve with classical bottom-up approaches. Complete maps of PTMs and assessment of single aminoacid polymorphisms are only a few of the results that can be obtained with this technique. Despite some existing technical and economical limitations, TD analysis is at present the most powerful instrument for MS-based proteomics and its implementation in routine workflow is a rapidly approaching turning point in proteomics. In this review article, the state-of-the-art of TD approach is described along with its major advantages and drawbacks and the most recent trends in TD analysis are discussed. References for all the covered topics are reported in the text, with the aim to support both newcomers and mass spectrometrists already introduced to TD proteomics.
In addition to a variety of other techniques used in T-cell epitope identification, mass spectrometery coupled to liquid chromatography have now become an important and sensitive tool in separation, ...detection, and sequence analysis of highly complex natural major histocompatibility complex (MHC) ligand mixtures. In this article, we present current strategies for the identification of MHC eluted peptides using high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) with a particular recall to those presented in the context of the non classical human leukocytes antigen (HLA) class I molecule HLA-E. In addition we also discuss the advantages and disadvantages of the methods available in the literature to concentrate and fractionate the peptides prior to analysis by mass spectrometry. An application of our method for isolation and characterization of peptides presented in the context of HLA-E is finally reported.
Escherichia coli is a robust, economic and rapid expression system for the production of recombinant therapeutic proteins. However, the expression in bacterial systems of complex molecules such as ...antibodies and fusion proteins is still affected by several drawbacks. We have previously described a procedure based on uteroglobin (UG) for the engineering of very soluble and stable polyvalent and polyspecific fusion proteins in mammalian cells (Ventura et al. 2009. J. Biol. Chem. 284∶26646-26654.) Here, we applied the UG platform to achieve the expression in E. coli of a bivalent human recombinant antibody (L19) toward the oncofetal fibronectin (B-FN), a pan-tumor target. Purified bacterial L19-UG was highly soluble, stable, and, in all molecules, the L19 moiety maintained its immunoreactivity. About 50-70% of the molecules were covalent homodimer, however after refolding with the redox couple reduced-glutathione/oxidized-glutathione (GSH/GSSG), 100% of molecules were covalent dimers. Mass spectrometry studies showed that the proteins produced by E. coli and mammalian cells have an identical molecular mass and that both proteins are not glycosylated. L19-UG from bacteria can be freeze-dried without any loss of protein and immunoreactivity. In vivo, in tumor-bearing mice, radio-iodinated L19-UG selectively accumulated in neoplastic tissues showing the same performance of L19-UG from mammalian cells. The UG-platform may represent a general procedure for production of various biological therapeutics in E. coli.
Taxol is an effective antineoplastic agent, originally extracted from the bark of Taxus brevifolia with a low yield. Many attempts have been made to produce Taxol by chemical synthesis, ...semi-synthesis and plant tissue cultures. However, to date, the availability of this compound is not sufficient to satisfy the commercial requirements. The aim of the present work was to produce suspension cell cultures from plants not belonging to Taxus genus and to verify whether they produced Taxol and taxanes. For this purpose different explants of hazel (Corylus avellana species) were used to optimize the protocol for inducing in vitro callus, an undifferentiated tissue from which suspension cell cultures were established.
Calli were successfully induced from stems, leaves and seeds grown in various hormone concentrations and combinations. The most suitable callus to establish suspension cell cultures was obtained from seeds. Media recovered from suspension cell cultures contained taxanes, and showed antiproliferative activity on human tumour cells. Taxol, 10-deacetyltaxol and 10-deacetylbaccatin III were the main taxanes identified. The level of Taxol recovered from the media of hazel cultures was similar to that found in yew cultures. Moreover, the production of taxanes in hazel cell cultures increased when elicitors were used.
Here we show that hazel cell cultures produce Taxol and taxanes under controlled conditions. This result suggests that hazel possesses the enzymes for Taxol production, which until now was considered to be a pathway particular to Taxus genus. The main benefit of producing taxanes through hazel cell cultures is that hazel is widely available, grows at a much faster rate in vivo, and is easier to cultivate in vitro than yew. In addition, the production of callus directly from hazel seeds shortens the culture time and minimizes the probability of contamination. Therefore, hazel could become a commercial source of Taxol and taxanes, both to be used as new therapeutic agents or as new precursors for Taxol semi-synthesis.
Abstract Background: Intravenous temsirolimus, an inhibitor of the mammalian target of rapamycin (mTOR), is approved for the treatment of advanced renal cell carcinoma (RCC). Sirolimus, the principal ...metabolite of temsirolimus in humans, also exhibits mTOR inhibitory activity. Objective: The purpose of this study was to compare the pharmacokinetics of temsirolimus and its metabolite, sirolimus, among patients with RCC not receiving dialysis and those receiving hemodialysis. Methods: This was a single-center, unblinded, single-dose study. Patients with histologically confirmed metastatic RCC were eligible. A single 25-mg dose of temsirolimus was administered as a 30-minute intravenous infusion during the first round of chemotherapy. Blood samples were drawn at 0 (predose), 0.5 (end of infusion), 1.5, 2.5, 5.5, 24, 72, and 144 hours after infusion. In patients receiving hemodialysis, an additional blood sample was drawn 1 hour after each treatment to compare pre- and postconcentration. Temsirolimus concentrations were assayed in blood using HPLC coupled to mass spectrometry. Pharmacokinetic parameters (Cmax , Tmax , t½ , AUC0-∞ , total body clearance, volume of distribution at steady state, AUC ratio the ratio of sirolimus to temsirolimus AUCs, and AUC sum the algebraic sum of temsirolimus and sirolimus AUCs) were calculated and analyzed statistically. Results: In total, 13 consecutive patients (11 men and 2 women; 11 not receiving dialysis and 2 receiving hemodialysis) were included. No patient refused to participate in the study. Of those not receiving dialysis, the median age was 54 years (range, 36–77 years), and of those receiving hemodialysis, the median age was 60.5 years (60–61 years). There were no significant between-group differences in the pharmacokinetic parameters of temsirolimus and sirolimus. Moreover, in patients receiving hemodialy-sis, blood drug concentrations assessed immediately before hemodialysis were similar to those assayed 1 hour after the treatment. Conclusion: This study found that after single-dose administration of 25 mg of temsirolimus as a 30-minute intravenous infusion, neither temsirolimus nor sirolimus concentrations were significantly affected in these patients with RCC receiving hemodi-alysis compared with those not receiving dialysis.
Thymbra spicata, a member of the Lamiaceae family, is native to eastern Mediterranean area. Leaves of this plant are rich in phenolic compounds and are a popular remedy of traditional medicine in ...Lebanon to prevent and/or counteract hyperlipidemia and hyperglycemia.
To evaluate the antisteatotic and antioxidant activities of extracts from leaves of Thymbra spicata L. using in vitro models of non-alcoholic fatty liver disease (NAFLD), a leading cause of liver-related morbidity and mortality worldwide, for whom no effective treatments are still available.
Two different extracts from Thymbra spicata L. aerial parts were prepared using water (TW) or ethanol (TE) as solvent. Their chemical composition was characterized by gas and liquid chromatography coupled with mass spectrometry. Both extracts were tested on cultured hepatic and endothelial cells treated to mimic in vitro a multisistemic pathology such as NAFLD. We assayed the effects on lipid accumulation, free radical production, lipid peroxidation, cell migration.
Both the total phenolic and the total flavonoid contents were higher in the ethanolic extract. Rosmarinic acid was the most abundant polyphenol in TW, while TE was richer in carvacrol. Our findings demonstrated that both extracts ameliorated lipid accumulation, oxidative stress and inflammation in the NAFLD cellular models. However, the aqueous extract was more effective to reduce hepatic steatosis, and the ethanolic extract had higheranti-oxidant potential and wound healing activity.
T. spicata extracts could be promising bioactive products to develop natural therapeutic agents or dietary supplements to treat NAFLD and obesity-related metabolic disease. Our findings suggest that while the ethanolic extract might be used in preventing endothelium dysfunction, the aqueous extract would act better as lipid-lowering agent.
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The bivalve Mytilus galloprovincialis has proven as a suitable model invertebrate for evaluating the potential impact of nanoparticles (NPs) in the marine environment. In particular, in mussels, the ...immune system represents a sensitive target for different types of NPs. In environmental conditions, both NP intrinsic properties and those of the receiving medium will affect particle behavior and consequent bioavailability/uptake/toxicity. However, the evaluation of the biological effects of NPs requires additional understanding of how, once within the organism, NPs interact at the molecular level with cells in a physiological environment. In mammalian systems, different NPs associate with serum soluble components, organized into a “protein corona”, which affects particle interactions with target cells. However, no information is available so far on the interactions of NPs with biological fluids of aquatic organisms.
In this work, the influence of hemolymph serum (HS) on the in vitro effects of amino modified polystyrene NPs (PS-NH2) on Mytilus hemocytes was investigated. Hemocytes were incubated with PS-NH2 suspensions in HS (1, 5 and 50µg/mL) and the results were compared with those obtained in ASW medium. Cell functional parameters (lysosomal membrane stability, oxyradical production, phagocytosis) were evaluated, and morphological changes were investigated by TEM. The activation state of the signalling components involved in Mytilus immune response (p38 MAPK and PKC) was determined. The results show that in the presence of HS, PS-NH2 increased cellular damage and ROS production with respect to ASW medium. The effects were apparently mediated by disregulation of p38 MAPK signalling. The formation of a PS-NH2-protein corona in HS was investigated by centrifugation, and 1D- gel electrophoresis and nano-HPLC-ESI-MS/MS. The results identified the Putative C1q domain containing protein (MgC1q6) as the only component of the PS-NH2 hard protein corona in Mytilus hemolymph. These data represent the first evidence for the formation of a NP bio-corona in aquatic organisms and underline the importance of the recognizable biological identity of NPs in physiological exposure medium when testing their potential impact environmental model organisms. Although the results obtained in vitro do not entirely reflect a realistic exposure scenario and the more complex formation of a bio-corona that is likely to occur in vivo, these data will contribute to a better understanding of the effects of NPs in marine invertebrates.
•The effects of PS-NH2 NPs on Mytilus hemocytes were compared in serum-HS and ASW.•HS increased cellular/lysosomal damage, ROS production and p-p38MAPK levels.•NP-corona proteins in HS were isolated and identified by MS.•NP-protein coronas in biological fluids can affect NP impact in marine species.
Iron (Fe) is the most important trace element in the ocean, as it is required by phytoplankton for photosynthesis and nitrate assimilation. Iron speciation is important to better understand the ...biogeochemical cycle and availability of this micronutrient, in particular in the Southern Ocean. Dissolved Fe (dFe) concentration and speciation were determined in 24 coastal subsurface seawater samples collected in the western Ross sea (Antarctica) during the austral summer 2017 as part of the CELEBeR (CDW Effects on glacial mElting and on Bulk of Fe in the Western Ross sea) project. ICP-DRC-MS was used for dFe determination, whereas CLE-AdSV was used to obtain the concentration of complexed and free dFe, of the ligands, and the values of the stability constants of the complexes. Dissolved Fe values ranged from 0.4 to 2.5 nM and conditional stability constant (log
K
’
Fe’L
) from 13.0 to 15.0, highlighting the presence of Fe-binding organic complexes of different stabilities. Principal component analysis (PCA) allowed us to point out that Terra Nova Bay and the neighboring area of Aviator and Mariner Glaciers were different in terms of chemical, physical, and biological parameters. A qualitative investigation on the nature of the organic ligands was carried out by HPLC–ESI–MS/MS. Results showed that siderophores represented a heterogeneous class of organic ligands pool.
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