Hepatic proteome sensitivity in rainbow trout after chronically exposed to a human pharmaceutical verapamil

Characterizing the origin of blood plasma proteins from organ tissues in rainbow trout (Oncorhynchus mykiss) using a comparative non-targeted proteomics approach

Protein expression patterns adapt to various cues to meet the needs of an organism. The dynamicity of an organism's proteome can therefore reveal information about an organism's health. Proteome databases contain limited information regarding organisms outside of medicinal biology. The UniProt human and mouse proteomes are extensively reviewed and ∼50 % of both proteomes include tissue specificity, while >99 % of the rainbow trout proteome lacks tissue specificity. This study aimed to expand knowledge on the rainbow trout proteome with a focus on understanding the origin of blood plasma proteins. Blood, brain, heart, liver, kidney, and gills were collected from adult rainbow trout, plasma and tissue proteins were analyzed using liquid chromatography tandem mass spectrometry. Over 10,000 proteins were identified across all groups. Our data indicated that the majority of the plasma proteome is shared amongst multiple tissue types, though 4-7 % of the plasma proteome is uniquely originated from each tissue (gill > heart > liver > kidney > brain).

Transcriptomic and proteomic analysis of Chinese rare minnow (Gobiocypris rarus) larvae in response to acute waterborne cadmium or mercury stress

In this study, Chinese rare minnow (Gobiocypris rarus) larvae were exposed to the control group, Cd concentrations (0.5 and 2.5 mg/L), and Hg concentrations (0.1 and 0.3 mg/L) for 96 h. Transcriptome analysis showed that 816 and 1599 significantly differentially expressed genes (DEGs) were identified in response to 2.5 mg/L Cd²⁺ and 0.3 mg/L Hg²⁺, respectively. Functional enrichment analysis revealed that DEGs were mostly associated with immune responses after Cd exposure, such as antigen processing and presentation, phagosome, apoptosis, and lysosome. Similarly, functional enrichment analysis showed that many pathways were mostly involved in metabolism after Hg exposure, such as glutathione metabolism and starch and sucrose metabolism. Results of two-dimensional electrophoresis (2-DE) showed that the abundance of 10 protein spots was significantly altered in the Cd²⁺ treatments. The proteomic analysis demonstrated that Cd toxicity might impair cytoskeletal and cell motility-related protein activity in the liver of G. rarus. Similarly, the abundance of 24 protein spots was significantly altered in the Hg²⁺ treatments. Hg toxicity regulates the expression of proteins belonging to several functional categories, including cytoskeleton, oxidative stress, digestive system, and energy metabolism. This study provides valuable relevant insight into the molecular mechanisms in response to Cd or Hg toxicity in aquatic organisms and will help screen for potential biomarkers to respond to Cd and Hg pollutants.

Environmentally relevant concentrations of carbamazepine induce liver histopathological changes and a gender-specific response in hepatic proteome of Chinese rare minnows (Gobiocypris rarus)

To assess hepatotoxicity and to determine the underlying mechanisms of carbamazepine (CBZ) toxicity in fish, histopathology and the liver proteome were examined after Chinese rare minnow (Gobiocypris rarus) were exposed to 1, 10, and 100 μg/L CBZ for 28 days. Histopathological changes included disruption of spatial structure, pyknotic nuclei, cellular vacuolization and deformation of cell nuclei, in addition to marked swelling of hepatocytes in all treatment groups. Protein analysis revealed that there were gender-specific responses in rare minnow following exposure, and there were 47 proteins in females and 22 proteins in males identified as differentially abundant following CBZ treatments. Pathway analysis revealed that cellular processes affected by CBZ included apoptosis, cell differentiation, cell proliferation, and the respiratory chain, indicating impaired energy homeostasis. Noteworthy was that 15 proteins identified as different in abundance were associated with carcinogenicity. Relative mRNA levels for select transcripts were consistent with the changes of proteins N-myc downstream regulated gene (NDRG), Tropomyosin 2-Beta (TPM2) and annexin A4 (ANXA4). Protein pyruvate kinase, liver and RBC (PKLR) were increased at 1 and 100 μg/L CBZ without significant difference in transcript levels. These findings characterize molecular responses and histological changes in the liver that generate new insights into CBZ hepatotoxicity in Chinese rare minnow.

Dietary Yeast Cell Wall Extract Alters the Proteome of the Skin Mucous Barrier in Atlantic Salmon (Salmo salar): Increased Abundance and Expression of a Calreticulin-Like Protein

In order to improve fish health and reduce use of chemotherapeutants in aquaculture production, the immunomodulatory effect of various nutritional ingredients has been explored. In salmon, there is evidence that functional feeds can reduce the abundance of sea lice. This study aimed to determine if there were consistent changes in the skin mucus proteome that could serve as a biomarker for dietary yeast cell wall extract. The effect of dietary yeast cell wall extract on the skin mucus proteome of Atlantic salmon was examined using two-dimensional gel electrophoresis. Forty-nine spots showed a statistically significant change in their normalised volumes between the control and yeast cell wall diets. Thirteen spots were successfully identified by peptide fragment fingerprinting and LC-MS/MS and these belonged to a variety of functions and pathways. To assess the validity of the results from the proteome approach, the gene expression of a selection of these proteins was studied in skin mRNA from two different independent feeding trials using yeast cell wall extracts. A calreticulin-like protein increased in abundance at both the protein and transcript level in response to dietary yeast cell wall extract. The calreticulin-like protein was identified as a possible biomarker for yeast-derived functional feeds since it showed the most consistent change in expression in both the mucus proteome and skin transcriptome. The discovery of such a biomarker is expected to quicken the pace of research in the application of yeast cell wall extracts.

Short-term exposure to L-type calcium channel blocker, verapamil, alters the expression pattern of calcium-binding proteins in the brain of goldfish, Carassius auratus

The influx of calcium ions (Ca(2+)) is responsible for various physiological events including neurotransmitter release and synaptic modulation. The L-type voltage dependent calcium channels (L-type VDCCs) transport Ca(2+) across the membrane. Calcium-binding proteins (CaBPs) bind free cytosolic Ca(2+) and prevent excitotoxicity caused by sudden increase in cytoplasmic Ca(2+). The present study was aimed to understand the regulation of expression of neuronal CaBPs, namely, calretinin (CR) and parvalbumin (PV) following blockade of L-type VDCCs in the CNS of Carassius auratus. Verapamil (VRP), a potent L-type VDCC blocker, selectively blocks Ca(2+) entry at the plasma membrane level. VRP present in the aquatic environment at a very low residual concentration has shown ecotoxicological effects on aquatic animals. Following acute exposure for 96h, median lethal concentration (LC50) for VRP was found to be 1.22mg/L for goldfish. At various doses of VRP, the behavioral alterations were observed in the form of respiratory difficulty and loss of body balance confirming the cardiovascular toxicity caused by VRP at higher doses. In addition to affecting the cardiovascular system, VRP also showed effects on the nervous system in the form of altered expression of PV. When compared with controls, the pattern of CR expression did not show any variations, while PV expression showed significant alterations in few neuronal populations such as the pretectal nucleus, inferior lobes, and the rostral corpus cerebellum. Our result suggests possible regulatory effect of calcium channel blockers on the expression of PV.

Verapamil – L type voltage gated calcium channel inhibitor diminishes aggressive behavior in male Siamese fighting fish

Verapamil is a L-type voltage gated calcium channels inhibitor (VGCCI), which is a highly prescribed drug used in the treatment of hypertension, angina pectoris, cardiac arrhythmia and cluster headaches. Its common use caused its appearance in water environment. VGCC inhibit epinephrine release and cause many neuro-hormonal changes influencing also fish behavior. Siamese fighting fish was chosen to study the influence of verapamil given to the water on the beginning of experiment in 3 different concentrations of 0 (control), 8 and 160 μg · L−1, on aggressive behavior in these fish. The experimental fish were placed in individual glass containers for 3 weeks and the mirror test was used. The highest concentration led to a significant modulation of fish behavior after 1 week and the lower dose caused statistically significant behavioral changes after 2 weeks of verapamil treatment. Siamese fighting fish males exposed to verapamil had longer latencies to the first chase – 12.6 s (8 μg · L−1 of verapamil) and 18.8 s (160 μg · L−1 of verapamil) compared to 5.6 s in the control group, decreased attack frequency and shorter duration of these attacks. The number of attacks within 10 min was decreased from 38.3 in the control group to 27.1 and 16.1, respectively. Also the total duration of these attacks decreased from 354.8 (control) to 326.4 (decrease statistically insignificant) and to 194.8 s in verapamil treated groups. It was shown, that even relatively low concentrations of verapamil in water may have adverse effects on fish and probably other living organisms.

In vitro effects of bisphenol A on the quality parameters, oxidative stress, DNA integrity and adenosine triphosphate content in sterlet (Acipenser ruthenus) spermatozoa

Among endocrine disruptors, the xenoestrogen bisphenol A (BPA) deserves particular attention due to widespread human exposure. Besides hormonal effects, BPA has been suspected to be responsible for adverse effect on reproductive ability of various species. In the present study the effect of BPA on the quality parameters, oxidative stress, the DNA integrity and intracellular ATP content of sterlet (Acipenser ruthenus) spermatozoa were investigated in vitro. Fish spermatozoa were exposed to concentrations of BPA possibly occurring in nature (0.5, 1.75, 2.5, 5 and 10μg/L) for 2h. Results revealed that BPA significantly decreased spermatozoa motility and velocity of spermatozoa at concentration of BPA 2.5-10μg/L. Significant positive correlation (r=0.713, P<0.05) was found between percent motile spermatozoa and ATP content. Oxidative stress was observed at concentrations 1.75-10μg/L, as reflected by significantly higher levels of protein and lipid oxidation and superoxide dismutase activity. Intracellular ATP content of spermatozoa decreased with increasing concentrations of BPA. A dramatic increase in DNA fragmentation expressed as percent tail DNA (2.2%±0.46) and Olive tail moment (0.37±0.09 arbitrary units) was recorded at concentrations of 1.75μg/L and above. The present study confirms that concentrations of BPA that can be encountered in nature are capable to induce oxidative stress, leading to impaired sperm quality, DNA fragmentation and intracellular ATP content.