Establishment and characterization of cytochrome P450 1A1 CRISPR/Cas9 Knockout Bovine Foetal Hepatocyte Cell Line (BFH12)

The cytochrome P450 1A (CYP1A) subfamily of xenobiotic metabolizing enzymes (XMEs) consists of two different isoforms, namely CYP1A1 and CYP1A2, which are highly conserved among species. These two isoenzymes are involved in the biotransformation of many endogenous compounds as well as in the bioactivation of several xenobiotics into carcinogenic derivatives, thereby increasing the risk of tumour development. Cattle (Bos taurus) are one of the most important food-producing animal species, being a significant source of nutrition worldwide. Despite daily exposure to xenobiotics, data on the contribution of CYP1A to bovine hepatic metabolism are still scarce. The CRISPR/Cas9-mediated knockout (KO) is a useful method for generating in vivo and in vitro models for studying xenobiotic biotransformations. In this study, we applied the ribonucleoprotein (RNP)-complex approach to successfully obtain the KO of CYP1A1 in a bovine foetal hepatocyte cell line (BFH12). After clonal expansion and selection, CYP1A1 excision was confirmed at the DNA, mRNA and protein level. Therefore, RNA-seq analysis revealed significant transcriptomic changes associated with cell cycle regulation, proliferation, and detoxification processes as well as on iron, lipid and mitochondrial homeostasis. Altogether, this study successfully generates a new bovine CYP1A1 KO in vitro model, representing a valuable resource for xenobiotic metabolism studies in this important farm animal species.

Contaminants from dredged sediments alter the transcriptome of Manila clam and induce shifts in microbiota composition

BACKGROUND

The reuse of dredged sediments in ports and lagoons is a big issue as it should not affect the quality and the equilibrium of ecosystems. In the lagoon of Venice, sediment management is of crucial importance as sediments are often utilized to built-up structures necessary to limit erosion. However, the impact of sediment reuse on organisms inhabiting this delicate area is poorly known. The Manila clam is a filter-feeding species of high economic and ecological value for the Venice lagoon experiencing a drastic decline in the last decades. In order to define the molecular mechanisms behind sediment toxicity, we exposed clams to sediments sampled from different sites within one of the Venice lagoon navigable canals close to the industrial area. Moreover, we investigated the impacts of dredged sediments on clam's microbial communities.

RESULTS

Concentrations of the trace elements and organic chemicals showed increasing concentrations from the city of Venice to sites close to the industrial area of Porto Marghera, where PCDD/Fs and PCBs concentrations were up to 120 times higher than the southern lagoon. While bioaccumulation of organic contaminants of industrial origin reflected sediments' chemical concentrations, metal bioaccumulation was not consistent with metal concentrations measured in sediments probably due to the activation of ABC transporters. At the transcriptional level, we found a persistent activation of the mTORC1 signalling pathway, which is central in the coordination of cellular responses to chemical stress. Microbiota characterization showed the over-representation of potential opportunistic pathogens following exposure to the most contaminated sediments, leading to host immune response activation. Despite the limited acquisition of new microbial species from sediments, the latter play an important role in shaping Manila clam microbial communities.

CONCLUSIONS

Sediment management in the Venice lagoon will increase in the next years to maintain and create new canals as well as to allow the operation of the new mobile gates at the three Venice lagoon inlets. Our data reveal important transcriptional and microbial changes of Manila clams after exposure to sediments, therefore reuse of dredged sediments represents a potential risk for the conservation of this species and possibly for other organisms inhabiting the Venice lagoon.

An In Vivo Whole-Transcriptomic Approach to Assess Developmental and Reproductive Impairments Caused by Flumequine in Daphnia magna

Among veterinary antibiotics, flumequine (FLU) is still widely used in aquaculture due to its efficacy and cost-effectiveness. Although it was synthesized more than 50 years ago, a complete toxicological framework of possible side effects on non-target species is still far from being achieved. The aim of this research was to investigate the FLU molecular mechanisms in Daphnia magna, a planktonic crustacean recognized as a model species for ecotoxicological studies. Two different FLU concentrations (2.0 mg L^-1 and 0.2 mg L^-1) were assayed in general accordance with OECD Guideline 211, with some proper adaptations. Exposure to FLU (2.0 mg L^-1) caused alteration of phenotypic traits, with a significant reduction in survival rate, body growth, and reproduction. The lower concentration (0.2 mg L^-1) did not affect phenotypic traits but modulated gene expression, an effect which was even more evident under the higher exposure level. Indeed, in daphnids exposed to 2.0 mg L^-1 FLU, several genes related with growth, development, structural components, and antioxidant response were significantly modulated. To the best of our knowledge, this is the first work showing the impact of FLU on the transcriptome of D. magna.

Deepening the Whole Transcriptomics of Bovine Liver Cells Exposed to AFB1: A Spotlight on Toll-like Receptor 2

Aflatoxin B1 (AFB1) is a food contaminant metabolized mostly in the liver and leading to hepatic damage. Livestock species are differently susceptible to AFB1, but the underlying mechanisms of toxicity have not yet been fully investigated, especially in ruminants. Thus, the aim of the present study was to better characterize the molecular mechanism by which AFB1 exerts hepatotoxicity in cattle. The bovine fetal hepatocyte cell line (BFH12) was exposed for 48 h to three different AFB1 concentrations (0.9 µM, 1.8 µM and 3.6 µM). Whole-transcriptomic changes were measured by RNA-seq analysis, showing significant differences in the expression of genes mainly involved in inflammatory response, oxidative stress, drug metabolism, apoptosis and cancer. As a confirmatory step, post-translational investigations on genes of interest were implemented. Cell death associated with necrosis rather than apoptosis events was noted. As far as the toxicity mechanism is concerned, a molecular pathway linking inflammatory response and oxidative stress was postulated. Toll-Like Receptor 2 (TLR2) activation, consequent to AFB1 exposure, triggers an intracellular signaling cascade involving a kinase (p38β MAPK), which in turn allows the nuclear translocation of the activator protein-1 (AP-1) and NF-κB, finally leading to the release of pro-inflammatory cytokines. Furthermore, a p38β MAPK negative role in cytoprotective genes regulation was postulated. Overall, our investigations improved the actual knowledge on the molecular effects of this worldwide relevant natural toxin in cattle.

The new PFAS C6O4 and its effects on marine invertebrates: First evidence of transcriptional and microbiota changes in the Manila clam Ruditapes philippinarum

There is growing concern for the wide use ofperfluorooctanoic acid (PFOA) because of its toxic effects on the environment and on human health. A new compound - the so called C6O4 (perfluoro ([5-methoxy-1,3-dioxolan-4-yl]oxy) acetic acid) - was recently introduced as one of the alternative to traditional PFOA, however this was done without any scientific evidence of the effects of C6O4 when dispersed into the environment. Recently, the Regional Agency for the Protection of the Environment of Veneto (Italy) detected high levels of C6O4 in groundwater and in the Po river, increasing the alarm for the potential effects of this chemical into the natural environment. The present study investigates for the first time the effects of C6O4 on the Manila clam Ruditapes philippinarum exposed to environmental realistic concentrations of C6O4 (0.1 µg/L and 1 µg/L) for 7 and 21 days. Furthermore, in order to better understand if C6O4 is a valid and less hazardous alternative to its substitute, microbial and transcriptomic alterations were also investigated in clams exposed to 1 µg/L ofPFOA. Results indicate that C6O4 may cause significant perturbations to the digestive gland microbiota, likely determining the impairment of host physiological homeostasis. Despite chemical analyses suggest a 5 times lower accumulation potential of C604 as compared to PFOA in clam soft tissues, transcriptional analyses reveal several alterations of gene expression profile. A large part of the altered pathways, including immune response, apoptosis regulation, nervous system development, lipid metabolism and cell membrane is the same in C6O4 and PFOA exposed clams. In addition, clams exposed to C6O4 showed dose-dependent responses as well as possible narcotic or neurotoxic effects and reduced activation of genes involved in xenobiotic metabolism. Overall, the present study suggests that the potential risks for marine organism following environmental contamination are not reduced by replacing PFOA with C6O4. In addition, the detection of both C6O4 and PFOA into tissues of clams inhabiting the Lagoon of Venice - where there are no point sources of either compounds - recommends a similar capacity to spread throughout the environment. These results prompt the urgent need to re-evaluate the use of C6O4 as it may represent not only an environmental hazard but also a potential risk for human health.

The effects of glyphosate and AMPA on the mediterranean mussel Mytilus galloprovincialis and its microbiota

Glyphosate, the most widely used herbicide worldwide, targets the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) enzyme in the shikimate pathway found in plants and some microorganisms. While the potential for glyphosate to induce a broad range of biological effects in exposed organisms has been demonstrated, the global molecular mechanisms of toxicity and potential effects in bacterial symbionts remain unclear, in particular for ecologically important marine species such as bivalve molluscs. Here, the effects of glyphosate (GLY), its degradation product aminomethylphosphonic acid (AMPA), and a mixture of both (MIX) on the mussel M. galloprovincialis were assessed in a controlled experiment. For the first time, next generation sequencing (RNA-seq and 16S rRNA amplicon sequencing) was used to evaluate such effects at the molecular level in both the host and its respective microbiota. The results suggest that the variable capacity of bacterial species to proliferate in the presence of these compounds and the impairment of host physiological homeostasis due to AMPA and GLY toxicity may cause significant perturbations to the digestive gland microbiota, as well as elicit the spread of potential opportunistic pathogens such as Vibrio spp.. The consequent host-immune system activation identified at the molecular and cellular level could be aimed at controlling changes occurring in the composition of symbiotic microbial communities. Overall, our data raise further concerns about the potential adverse effects of glyphosate and AMPA in marine species, suggesting that both the effects of direct toxicity and the ensuing changes occurring in the host-microbial community must be taken into consideration to determine the overall ecotoxicological hazard of these compounds.

Host-microbiota interactions shed light on mortality events in the striped venus clam Chamelea gallina

Mass mortalities due to disease outbreaks have recently affected a number of major taxa in marine ecosystems. Climate- and pollution-induced stress may compromise host immune defenses, increasing the risk of opportunistic diseases. Despite growing evidence that mass mortality events affecting marine species worldwide are strongly influenced by the interplay of numerous environmental factors, the reductionist approaches most frequently used to investigate these factors hindered the interpretation of these multifactorial pathologies. In this study, we propose a broader approach based on the combination of RNA-sequencing and 16S microbiota analyses to decipher the factors underlying mass mortality in the striped venus clam, Chamelea gallina, along the Adriatic coast. On one hand, gene expression profiling and functional analyses of microbial communities showed the over-expression of several genes and molecular pathways involved in xenobiotic metabolism, suggesting potential chemical contamination in mortality sites. On the other hand, the down-regulation of several genes involved in immune and stress response, and the over-representation of opportunistic pathogens such as Vibrio and Photobacterium spp. indicates that these microbial species may take advantage of compromised host immune pathways and defense mechanisms that are potentially affected by chemical exposure, resulting in periodic mortality events. We propose the application of our approach to interpret and anticipate the risks inherent in the combined effects of pollutants and microbes on marine animals in today's rapidly changing environment.

CT cystoscopy in the evaluation of bladder tumors

The aim of the present study was to assess the role of virtual cystoscopy in the identification of bladder tumors. Fifteen patients (11 men and 4 women, median age: 61 years, range: 46-74 years) with a positive finding of bladder tumor at fiber-optic cystoscopy were studied by multislice-CT. Scans were downloaded to a workstation with the aid of a software for the processing of 3-D reconstructions, with a volume-rendering technique which allowed the "navigation" within the bladder in search of wall lesions. In this group of 15 patients, cystoscopy was able to detect 19 neoplastic lesions, 13 with a diameter >10 mm and 6 with a diameter <10 mm. Virtual cystoscopy, instead, identified 17 lesions (89%) only. In particular, all those lesions with a diameter >1 cm (13/13=100%) were correctly identified, whereas only 4 of the 6 lesions with a diameter <1 cm were depicted. The 2 false negative cases were 2 lesions with a flat morphology, measuring 5 and 6 mm. Most recent technological advances allowed the employement of virtual endoscopies, characterized by the absence of invasivity as compared with fiber-optic studies and based on data obtained by spiral- and multislice-CTs. According to our experience, virtual CT-cystoscopy revealed to be a complementary tool in the evaluation of cross-sectional images and proved to be an easy procedure without complications, well-accepted by the patients, and with a reliable detection of those bladder lesions measuring more than 5 mm in case of polypoid formations and at least 10 mm in case of flat lesions. This technique, however, does not allow the collection of a bioptic sample and--with the present resolution power of available equipments--it could be unable to correctly detect small-sized flat lesions. We, nonetheless, believe that this procedure, in the future, thanks to rapid technological improvements in virtual imaging techniques, could become a useful diagnostic tool in the management of those patients with bladder tumors. Further studies on larger study groups are therefore desirable for a more reliable validation of the technique.

[Optimization of the technique of virtual colonoscopy using a multislice spiral computerized tomography]

PURPOSE

To optimize scanning parameters for virtual colonoscopy utilizing a multislice Helical CT scanner in an in vitro study (using a homemade colonic phantom) and in a preliminary clinical study.

MATERIAL AND METHODS

A colonic phantom was built using a plastic tube and 12 plastiline polyps were placed inside. The colonic phantom was studied with a multislice Helical CT scanner. Axial images were obtained with the phantom parallel to the long axis of the moving table (in order to simulate the evaluation of ascending and descending colon): oblique images were acquired with the phantom at 45 degrees relative to the long axis of the moving table (in order to simulate the evaluation of sigmoid colon and colonic flexures). Four different scanning protocols were tested: 1) slice collimation, 5 mm; slice width, 7 mm; table speed, 25 mm; reconstruction index, 5 mm; 2) slice collimation, 2.5 mm; slice width, 3 mm; table speed, 15 mm; reconstruction index, 3 mm; 3) slice collimation, 1 mm; slice width, 1.25 mm; table speed, 5 mm; reconstruction index, 1 mm; 4) slice collimation, 1 mm; slice width, 1.25 mm; table speed, 4 mm; reconstruction index, 1 mm. Quantitative analysis consisted in evaluation of the number of identified polyps and polyp size along the longitudinal axis. Qualitative analysis consisted in the evaluation of image artifacts and quality of 3D reconstructed images (step artifacts and polyp geometry distortion). This preliminary clinical study was performed in 12 patients (7 men and 5 women) who underwent multislice Helical CT colonography. We selected patients with clinical indications for conventional colonoscopy or after unsuccessful conventional colonoscopy.

RESULTS

Multislice Helical CT colonography was 100% sensitive in the detection of all polyps and in all scanning protocols. With oblique scans, only a 3-mm polyp was missed during protocol 1 (sensitivity: 92%). Polyp geometry distortion was observed on longitudinal reconstructions, whereas no distortion was seen on axial images. Image quality was graded as optimal for protocols 2, 3, and 4; protocol 1 was graded as good on transverse scans and as poor on oblique scans. In our preliminary clinical study, two colonic carcinomas and three polyps were identified.

CONCLUSIONS

At present, the introduction of multislice technology in virtual colonoscopy permits to improve spatial resolution and image definition. The actual clinical advantage, in terms of increased diagnostic accuracy, needs further investigation in larger clinical studies.