Roberto Anedda

Development of polymeric microbubbles targeted to prostate-specific membrane antigen as prototype of novel ultrasound contrast agents.

Ultrasound-targeted microbubbles (MBs) offer new opportunities to enhance the capabilities of diagnostic ultrasound (US) imaging to specific pathological tissue. Herein, we report on the design and development of a novel prototype of US contrast agent based on polymeric MBs targeted to prostate-specific membrane antigen (PSMA) for use in the diagnosis of prostate cancer (PCa). First, a set of air-filled MBs by a variety of biocompatible polymers were prepared and characterized in terms of morphology and echogenic properties after exposure to US. MBs derived from poly(D,L-lactic-co-glycolic acid) (PLGA)-poly(ethylene glycol) (PEG) copolymer resulted as the most effective in terms of reflectivity. Such polymer was therefore preconjugated with a urea-based PSMA inhibitor molecular probe (DCL), and the obtained MBs were investigated in vitro for their targeting efficacy toward PSMA positive PCa (LNCaP) cells. Fluorescence microscopy proved a specific and efficient adhesion of targeted MBs to LNCaP cells. To our knowledge, this work reports the first model of polymeric MBs appropriately engineered to target PSMA, which might be further optimized and used for PCa diagnosis and potential carriers for selective drug delivery.

Impact of three commercial feed formulations on farmed gilthead sea bream (Sparus aurata, L.) metabolism as inferred from liver and blood serum proteomics

BackgroundThe zootechnical performance of three different commercial feeds and their impact on liver and serum proteins of gilthead sea bream (Sparus aurata, L.) were assessed in a 12 week feeding trial. The three feeds, named A, B, and C, were subjected to lipid and protein characterization by gas chromatography (GC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), respectively.ResultsFeed B was higher in fish-derived lipids and proteins, while feeds C and A were higher in vegetable components, although the largest proportion of feed C proteins was represented by pig hemoglobin. According to biometric measurements, the feeds had significantly different impacts on fish growth, producing a higher average weight gain and a lower liver somatic index in feed B over feeds A and C, respectively. 2D DIGE/MS analysis of liver tissue and Ingenuity pathways analysis (IPA) highlighted differential changes in proteins involved in key metabolic pathways of liver, spanning carbohydrate, lipid, protein, and oxidative metabolism. In addition, serum proteomics revealed interesting changes in apolipoproteins, transferrin, warm temperature acclimation-related 65 kDa protein (Wap65), fibrinogen, F-type lectin, and alpha-1-antitrypsin.ConclusionsThis study highlights the contribution of proteomics for understanding and improving the metabolic compatibility of feeds for marine aquaculture, and opens new perspectives for its monitoring with serological tests.

Influence of seasonal and environmental patterns on the lipid content and fatty acid profiles in gonads of the edible sea urchin Paracentrotus lividus from Sardinia

The influence of seasonal and environmental patterns on the lipid fraction of Paracentrotus lividus gonads was investigated. For this purpose, sea urchins were collected monthly over a year from two Sardinian coastal areas. Total lipids in gonads follow an annual cyclical trend, described by a sine wave curve, that it is more influenced by season than by growing area. The lowest lipid content in gonads corresponds to a high percentage of mature reproductive stages (i.e. winter season), independently of sampling area. A variation in total lipid content follows a change in photoperiod, while it is related to sea surface temperature. Multivariate analysis on fatty acid profiles of gonads, detected by gas chromatography, clusters the collected specimens mainly according to the sampling area, secondly according to the sites within the same sampling area and finally according to season.

Molecular details on gilthead sea bream (Sparus aurata) sensitivity to low water temperatures from 1H NMR metabolomics

Biometric and metabolic responses of gilthead sea bream to cold challenge are described following a growth trial divided into three water temperature steps, namely cooling, cold maintenance and recovery. Experimental data provide a useful description of fish response to thermal stress at both zootechnical and molecular level. Although no mortality has been observed, Nuclear Magnetic Resonance-based metabolomics confirms the marked sensitivity of this fish species to low water temperature, and explains some key molecular events associated to fish response to cold. Increase in hepatosomatic index is associated to liver fat accumulation, as a consequence of lipid mobilization from muscle and other extrahepatic tissues, and metabolic rearrangements linked to homeoviscous adaptation of cellular membranes are observed. Following primary responses to descending temperature from 18°C to 11°C, the energetic metabolism (insulin signaling, glycolysis) is first clearly affected; then, at constant low water temperature (11°C), the most perturbed metabolic pathways are related to methionine cycle in liver, while osmoregulatory function is exerted by TMAO in muscle. Water temperature recovery from 11°C to 18°C stimulates gluconeogenesis and glycogen synthesis activities at hepatic level, although the rate of a thermo-compensatory response seems to be slower than that of the cooling phase. The obtained results are intended to guide novel high-performance feed formulations for gilthead sea bream reared during winter.

Biometric and metabolic profiles associated to different rearing conditions in offshore farmed gilthead sea bream (Sparus aurata L.).

Modern multivariate methods are applied to both biometric measurements and NMR metabolic profiling of fillet to discriminate farmed gilthead sea bream reared in different farming conditions. Two fish groups having the same average size, from the same farm, were caught in May and October. Biometric data demonstrate that condition factor is higher for the leaner fish, sampled in May, while liver somatic index is lower in fish sampled in October. Biometric features are related to metabolic changes that involve lipid storage from May to September, and their mobilization from muscle and liver during prespawning season (September, October). Structural phospholipids (phosphatidylcholine, phosphatidylethanolamine) and essential fatty acids (eicosapentaenoic and docosahexaenoic acids) characterize the lipid profile of the May catch, while triglycerides, monounsaturated and diunsaturated fatty acids, likely from absorption of vegetable oil components of feeds, suggest fish fattening in the warm season and discriminate fish caught in October. Among polar metabolites, taurine, glutamine, glycine, alanine, and creatine/phosphocreatine confirm their role as good biomarkers for the discrimination among fish produced in different farming conditions, especially involving feed digestion and metabolism, chronic stress, and alteration of energetic balance in cage‐reared fish. Qualitative traits of farmed fish are therefore the result of a complex combination of environmental factors and farming practices, which should be analyzed to increase consumers’ and farmers’ awareness.

Proteomic changes occurring along gonad maturation in the edible sea urchin Paracentrotus lividus.

UNLABELLED The reproductive stage of Paracentrotus lividus strongly influences product quality that, in turn, impacts significantly on the market price. Large, compact and sweet gonads are preferred, and sensory attributes are positively related to the ratio of nutritive phagocytes to gametes. Gonads at advanced maturation stages, although larger, have less desirable attributes, being more watery and bitter especially in females. Therefore, the best compromise among size, texture, and taste needs to be reached. In this study, wild P. lividus were collected along coastal Sardinia, and gonads in the recovery, pre-mature, mature, and spent stages were analyzed by gel-based and by shotgun proteomics. A detailed characterization of the proteome changes occurring in gonads of both sexes along maturation was achieved, and significant modifications were seen in numerous proteins involved in nutrient accumulation in nutritive phagocytes, as well as in gamete biology and maturation. Adding to an improved understanding of the P. lividus reproductive cycle in its natural environment, the results described in this work may form the basis for defining novel protein markers and procedures for an easier sexing and staging, and for monitoring sea urchin gonad maturation cycles in aquaculture plants. Mass spectrometry data are deposited in ProteomeXchange (PXD004200). SIGNIFICANCE The sensory quality of P. lividus gonads is strongly influenced by the reproductive cycle, with significant changes in flavor, texture, and size. A better knowledge of the protein profiles, patterns, and markers associated with gonad sex and maturation stage can have useful implications for understanding and monitoring these changes. One of these is the ability to identify protein profiles specifically associated with a given stage and, in perspective, to identify maturation and sex markers. The comprehensive proteomic evaluation achieved in this work was made possible by the application of combined gel-based and shotgun approaches. As a result, this study generated the largest proteomic dataset available in the literature for P. lividus, as well as a general picture of protein abundance changes occurring along maturation.

Multidisciplinary analytical investigation of phospholipids and triglycerides in offshore farmed gilthead sea bream (Sparus aurata) fed commercial diets

In this work, a quantitative characterisation of lipid (both triglycerides and phospholipids) rearrangements in the muscle of offshore-raised gilthead sea bream was carried out as a function of fish growth between April and September. Relative percentages of lipid classes and fatty acids/acyls composition of the commercial feeds and fish dorsal muscles were assessed by means of an interdisciplinary analytical approach. A combination of preparative chemistry and experimental results from NMR spectroscopy, GC, 3D-TLC as well as proximate analysis permitted the observed growth parameters in key metabolic events to be linked with fish fattening and lipid turnover. While defined effects of feed composition on fatty acid profiles of fillets were ascertained, the relative increase of fatty acyls in triglycerides and phospholipids were also estimated enabling detailed evaluation of TAG:PL ratio in adult offshore-farmed gilthead sea bream. NMR was also used to quantify PUFA regiospecific distribution in TAG and PL.

Insights on the Relaxation of Liposomes Encapsulating Paramagnetic Ln-Based Complexes

Purpose: To describe and quantify the different relaxation mechanisms operating in suspensions of liposomes that encapsulate paramagnetic lanthanide(III) complexes. Theory and Methods: The transverse relaxation rate of lanthanide‐loaded liposomes receives contribution from the exchange between intraliposomal and bulk water protons, and from magnetic susceptibility effects. Phospholipids vesicles encapsulating different Ln(III)‐HPDO3A complexes (Ln = Eu, Gd, or Dy) were prepared using the conventional thin film rehydration method. Relaxation times (T1, T2, and T2*) were measured at 14 Tesla (T) and 25°C. The effect of compartmentalization of the paramagnetic agent inside the liposomal cavity was evaluated by means of an IRON‐modified MRI sequence. Results: NMR measurements demonstrated that Curie spin relaxation is the dominant contribution (> 90%) to the observed transverse relaxation rate of paramagnetic liposomes. This was further confirmed by MRI that showed the ability of the liposome entrapped lanthanide complexes to generate IRON‐MRI positive contrast in a size dependent manner. Conclusion: The Curie spin relaxation mechanism is by far the principal mechanism involved in the T2 shortening of the water protons in suspension of paramagnetic liposomes at 14T. The access to IRON contrast extends the potential of such nanosystems as MRI contrast agents. Magn Reson Med 74:468–473, 2015.

Proteomic dataset of Paracentrotus lividus gonads of different sexes and at different maturation stages

We report the proteomic dataset of gonads from wild Paracentrotus lividus related to the research article entitled “Proteomic changes occurring along gonad maturation in the edible sea urchin Paracentrotus lividus” [1]. Gonads of three individuals per sex in the recovery, pre-mature, mature, and spent stages were analyzed using a shotgun proteomics approach based on filter-aided sample preparation followed by tandem mass spectrometry, protein identification carried out using Sequest-HT as the search engine within the Proteome Discoverer informatics platform, and label-free differential analysis. The dataset has been deposited in the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PRIDE: PXD004200.