Bcl-2 and Caspase 3 mRNA levels in the testes of gudgeon, Gobio gobio, exposed to ethinylestradiol (EE2)

Fancd2os Reduces Testosterone Production by Inhibiting Steroidogenic Enzymes and Promoting Cellular Apoptosis in Murine Testicular Leydig Cells

BACKGRUOUND

It is well-established that serum testosterone in men decreases with age, yet the underlying mechanism of this change remains elusive.

METHODS

The expression patterns of Fancd2 opposite-strand (Fancd2os) in BALB/c male mice and testicular tissue derived cell lines (GC-1, GC-2, TM3, and TM4) were assessed using real-time polymerase chain reaction (RT-PCR), Western blot and immunofluorescence. The Fancd2os-overexpressing or knockdown TM3 cells were constructed by infecting them with lentivirus particles and were used to evaluated the function of Fancd2os. The testosterone production was measured using enzyme linked immunosorbent assay (ELISA) and the steroidogenic enzymes such as steroidogenic acute regulatory protein (StAR), P450 cholesterol side-chain cleavage (P450scc), and 3β-hydroxysteroid dehydrogenase (3β-HSD) were analysed using RT-PCR. The apoptosis of TM3 cells induced by ultraviolet light or testicular tissues was detected using flow cytometry, Western blot or dUTP-biotin nick end labeling (TUNEL) assays. Pearson correlation analysis was used to assess the correlation between the Fancd2os expression and TUNEL-positive staining in mouse testicular Leydig cells.

RESULTS

The Fancd2os protein was predominantly expressed in mouse testicular Leydig cells and its expression increased with age. Fancd2os overexpression inhibited testosterone levels in TM3 Leydig cells, whereas knockdown of Fancd2os elevated testosterone production. Fancd2os overexpression downregulated the levels of StAR, P450scc and 3β-HSD, while Fancd2os knockdown reversed this effect. Fancd2os overexpression promoted ultraviolet light-induced apoptosis of TM3 cells. In contrast, Fancd2os knockdown restrained apoptosis in TM3 cells. In vivo assays revealed that higher Fancd2os levels and mouse age were associated with increased apoptosis in Leydig cells and decreased serum testosterone levels. Pearson correlation analysis exhibited a strong positive correlation between the expression of Fancd2os and TUNEL-positive staining in mouse testicular Leydig cells.

CONCLUSION

Our findings suggest that Fancd2os regulates testosterone synthesis via both steroidogenic enzymes and the apoptotic pathway.

Ecotoxicological evaluation of zebrafish liver (Danio rerio) induced by dibutyl phthalate

Dibutyl phthalate (DBP), one of the most commonly applied plasticizers, has been frequently detected in the aquatic environment, posing potential risks to aquatic organisms. Currently, reports about the toxicity of zebrafish liver with DBP exposure are rare, and the toxic mechanism is still not clear. In this study, zebrafish (Danio rerio) were used to explore the ecotoxicological effects of DBP from the physiological, biochemical, genetic, and molecular levels. The results showed oxidative stress, lipid peroxidation, and DNA damage occurred in zebrafish liver according to changes in antioxidant enzymes, MDA and 8-OHdG content. AchE activity was always active, and negatively correlated with the DBP concentration. The expression of Cu/Zn-sod and gpx genes were similar to that of antioxidant enzymes from 7 to 21 days, while in the end, the inconsistent result appeared due to the time lag effect in protein modification, gene transcription and translation. Besides, the mRNA abundance of Caspase-3 and p53 were upregulated, showing a "dose-response" relationship. The integrated biomarker reaction indicated that the effects of exposure time on zebrafish liver was 14th day> 28th day> 7th day> 21th day. These results are of great significance to evaluate the toxicological effects and explore the toxic mechanism of DBP on aquatic organisms.

Impact of Estrogens Present in Environment on Health and Welfare of Animals

Simple Summary

Estrogens are a group of steroid hormones that recently have gained even more attention in the eyes of scientists. There is an ongoing discussion in the scientific community about their relevance as environmental contaminants and the danger they pose to animal health and welfare. In available literature we can find many examples of their negative effects and mechanisms that are involved with such phenomena.

Abstract

Nowadays, there is a growing interest in environmental pollution; however, knowledge about this aspect is growing at an insufficient pace. There are many potential sources of environmental contamination, including sex hormones—especially estrogens. The analyzed literature shows that estrone (E1), estradiol (E2), estriol (E3), and synthetic ethinyloestradiol (EE2) are the most significant in terms of environmental impact. Potential sources of contamination are, among others, livestock farms, slaughterhouses, and large urban agglomerations. Estrogens occurring in the environment can negatively affect the organisms, such as animals, through phenomena such as feminization, dysregulation of natural processes related to reproduction, lowering the physiological condition of the organisms, disturbances in the regulation of both proapoptotic and anti-apoptotic processes, and even the occurrence of neoplastic processes thus drastically decreasing animal welfare. Unfortunately, the amount of research conducted on the negative consequences of their impact on animal organisms is many times smaller than that of humans, despite the great richness and diversity of the fauna. Therefore, there is a need for further research to help fill the gaps in our knowledge.

Effect of water temperature on cellular stress responses in meagre (Argyrosomus regius)

Μeagre (Argyrosomus regius) is a newly introduced species in the aquaculture sector characterized by high growth rates and good nutritional value. However, the optimum conditions such as water temperature for the rearing of this species are still under research. The aim of the present study was to investigate several biochemical responses in the heart, muscle, liver, and intestine of meagre reared under different water temperatures (17, 23, and 26 °C) in comparison to the initial acclimation temperature at 20 °C. To assess its cellular stress response, the molecular markers of Hsp70 and Hsp90 induced levels, p38 MAPK and p44/42 MAPK phosphorylated levels, ubiquitin conjugates, and Bcl-2 levels were determined. Moreover, to investigate its antioxidant defense, the activities of superoxide dismutase, catalase, and glutathione reductase were measured. The obtained results in meagre showed a distinct tissue-specific response regarding the variations observed in the studied parameters under different acclimation temperatures. Specifically, most examined tissues presented a decrease in the levels of the examined markers compared to 20 °C, while in the intestine, an increase of Hsp70 and p38 MAPK levels was observed at 23 and 26 °C. However, data on the final weight and length of the fish lead to the conclusion that high water temperatures such as 26 °C might be the best for the rearing of this species. Therefore, it is assumed that the observed differential molecular responses may act in a cell-protective way at all temperatures, irrespectively of the effect of temperature on growth parameters.

Effects of partial dietary supplementation of fish meal with soymeal on the stress and apoptosis response in the digestive system of common dentex (Dentex dentex)

Background

Soybean is a common alternative protein source of plant origin in aquafeeds as it has a reasonably balanced amino acid profile and is widely available. This study aimed to investigate the influence of partial substitution of fish meal with soy meal on cytoprotective pathways and apoptosis in the digestive system of common dentex (Dentex dentex), using the activation of Hsp70, p38 MAPK, Bcl-2 and caspase-3. The experimental approach involved feeding of common dentex with three isoprotein and isoenergetic diets that contained fish meal as a protein source (FM), partial replacement of fish meal by soy meal 25% (SM25) and 40% (SM40) for 3 months.

Results

The SM40 diet induced Hsp70 activation only in the middle part of intestine. On the other hand, both SM25 and SM40 diets diminished the phosphorylation of p38 MAPK in the anterior and the middle part of intestine, whereas only SM25 induced p38 MAPK phosphorylation in the stomach. Moreover, a decrease in the levels of caspase-3 activity was observed in the middle and posterior intestine, as well as in the stomach after feeding with SM25 diets. Furthermore, Bcl-2 levels were increased by SM40 in the anterior and by SM25 in the middle part of intestine.

Conclusions

SM25 and SM40 diets elicited a tissue and soy concentration specific cellular and cell protective response in the different parts of the digestive tract in common dentex.

Early developmental exposure to pentachlorophenol causes alterations on mRNA expressions of caspase protease family in zebrafish embryos

Caspase proteases play an essential role in cell apoptosis and inflammation, thus matter greatly in animal development and other biological processes. As a ubiquitous environmental pollutant, pentachlorophenol (PCP) is considered to have adverse effects on animal apoptosis during embryonic development, yet the evidence that PCP interfere with caspase genes was seldom reported. To uncover the effects of PCP on caspases expression in early embryos of zebrafish, two concentrations of PCP (5 μg/L and 200 μg/L) were chosen and 14 types of caspase genes at two different developmental stages, 8 h post-fertilization (hpf) and 24 hpf were analyzed. Lower survival and hatching rates, distinct developmental delay and morphological deformities of head and tail were observed. PCP, especially in the high concentration, significantly altered the expressions of most caspase genes. At 8 hpf, PCP had the most significant inductive effects on gene casp8l2 with fold changes (FCs) of 6.87 at 5 μg/L and 4.48 at 200 μg/L, and casp6l1 (with FCs of 3.15/3.69), and inhibitory effects on caspa (with FCs of 0.93/0.53) and caspb (with FCs of 0.99/0.57). At 24 hpf, PCP had the most significant effects on casp6l2, casp9, and caspc. PCP exposure possibly disrupted intrinsic apoptosis pathway considering its effects on casp9 expression. In addition, most caspase genes exhibited higher levels at 24 hpf than 8 hpf except caspc. Our results suggested that PCP had different effects on varied caspase genes, which probably resulting in a profound impact on caspase proteins and apoptosis processes and, ultimately, developmental abnormality.

Disruption of apoptosis pathways involved in zebrafish gonad differentiation by 17α-ethinylestradiol and fadrozole exposures

Zebrafish (Danio rerio) sex determination seems to involve genetic factors (GSD) but also environmental factors (ESD), such as endocrine disrupting chemicals (EDCs) that are known to mimic endogenous hormones and disrupt gonad differentiation. Apoptosis has also been proposed to play a crucial role in zebrafish gonad differentiation. Nevertheless, the interactions between EDCs and apoptosis have received little attention. Thus, this study aimed to assess if and which apoptotic pathways are involved in zebrafish gonad differentiation and how EDCs may interfere with this process. With these purposes, zebrafish were exposed to 17α-ethinylestradiol (EE2, 4ng/L) and fadrozole (Fad, 50μg/L) from 2h to 35days post-fertilization (dpf). Afterwards, a gene expression analysis by qRT-PCR and a stereological analysis, based on systematic sampling and protein immunohistochemistry, were performed. The death receptors (FAS; TRADD), anti-apoptotic (BCL-2; MDM2), pro-apoptotic (CASP-2 and -6) and cell proliferation (BIRC5/survivin; JUN) genes and proteins were evaluated. In general, apoptosis was inhibited in females through the involvement of anti-apoptotic pathways, while in males apoptosis seemed to be crucial to the failure of the "juvenile ovary" development and the induction of testes transformation. The JUN protein was shown to be necessary in juvenile ovaries, while the BIRC5 protein seemed to be involved in zebrafish spermatogenesis. Both EDCs, EE2 and Fad, increased the apoptosis stimulus in zebrafish gonad. It was noticed that the few females that were resistant to Fad-induced sex reversal had increased anti-apoptotic factor levels, while males exposed to EE2 showed increased pro-apoptotic genes/proteins and were more advanced in gonad differentiation. Overall, our findings show that apoptosis pathways are involved in zebrafish gonad differentiation and that EDCs can disrupt this process.

Identification, characterization and functional analysis of anti-apoptotic protein BCL-2-like gene from pufferfish, Takifugu obscurus, responding to bacterial challenge

Apoptosis plays a crucial role in many biological processes, including development, cellular homeostasis and immune responses. The BCL-2 family is a key regulator of the mitochondrial response to apoptotic signals in the intrinsic pathway. In this study, we identified and characterized the cDNA and expression pattern of pufferfish BCL-2 (PfBCL-2). The full-length cDNA of PfBCL-2 was 1412 bp with an open reading frame of 657 bp encoding a putative protein of 219 amino acids (Accession no: KP898414). The calculated molecular mass of the PfBCL-2 was 24.2 kDa with a predicted isoelectric point of 5.27. The deduced PfBCL-2 protein exhibited four highly conserved BCL-2 homology domains, suggesting that PfBCL-2 may play a similar role in the apoptotic-signaling pathway as in other species. Real-time PCR results showed that PfBCL-2 transcript was expressed in a wide range of tissues but exhibited the greatest level of expression in blood. Transcriptional responses of PfBCL-2 exhibited different spatial and temporal expression profiles in liver and blood after bacterial infection. PfBcl-2 transcript was significantly up-regulated in liver at 6, 12, 24 and 48 h (with maximum induction at 48 h) and was up-regulated in blood at 3, 6, 12 and 24 h (with maximum induction at 12 h). Meanwhile, recombinant PfBCL-2 fused with His6 tag was efficiently expressed in Escherichia coli BL21 (DE3) and purified using Ni-nitrilotriacetic acid resin. Western blot analysis indicated that its protein level appeared to be elevated during the initial bacterial infection. These results suggest that PfBCL-2 plays important roles in immune responses against bacteria challenge.

RNA-Seq-based transcriptome analysis of Korean rose bitterling (Rhodeus uyekii) exposed to synthetic estrogen 17-α-ethinylestradiol (EE2)

The potential impact of natural and synthetic estrogens on aquatic ecosystems has become a subject of great interest in recent years. One synthetic estrogen, 17-alpha-ethinylestradiol (EE2), is present in municipal sewage discharges and causes gonad alterations in various fish species. To understand the possible damage caused by EE2, male Rhodeus uyekii were exposed to 100 ng/L EE2 for 7 days. RNA-Seq was performed to assess the effects of EE2 on gene expression in hepatic and skin tissues. The analysis revealed that EE2 induced the expression of various genes, including sex hormone genes, anti-Mullerian hormone, vitellogenin, and estrogen receptor alpha; cancer genes, breast cancer anti-estrogen resistance protein 3, caveolin 2, and Smad2; and apoptotic genes, p53, Bcl-2, TNF-α, and WDR36. These results suggest that the synthetic estrogen EE2 disturbs the endocrine system and regulates both carcinogenic and apoptotic gene expressions in R. uyekii.

Assessment of the health status of wild fish inhabiting a cotton basin heavily impacted by pesticides in Benin (West Africa)

To determine the impact of agricultural pesticides used in cotton cultivation on the health status of fish living in a Beninese cotton basin, we compared the reproductive and hepatic systems of fish sampled from rivers located in both contaminated and pristine conditions. Different types of biomarkers, including biometric indices (a condition factor K, a gonadosomatic index GSI, and a hepatosomatic index HSI), plasma levels of sex steroids (11-ketotestosterone 11-KT, testosterone T and estradiol-17β E2) and the histopathology of the gonads and liver, were investigated for two different trophic levels of the following two fish species: the Guinean tilapia Tilapia guineensis and the African catfish Clarias gariepinus. The fish were captured during both the rainy season (when there is heavy use of pesticides on cotton fields) and the dry season from one site, in Pendjari River (reference site), which is located outside the cotton-producing basin, and from three other sites on the Alibori River within the cotton-producing basin. Comparing fish that were sampled from contaminated (high levels of endosulfan, heptachlor and DDT and metabolites) and reference sites, the results clearly indicated that agricultural pesticides significantly decreased K and GSI while they increased HSI, regardless of the season, species and sex of the fish. These pesticides also induced a decrease in the plasma levels of 11-KT and T and increased those of E2. The histopathology of the testes revealed, in both species, a high rate of testicular oocytes, up to 50% in the African catfish, downstream of the Alibori River, which indicated estrogenic effects from the pesticides. The disruption of male spermatogenesis primarily included necrosis, fibrosis and the presence of foam cells in the lobular lumen. The histopathology of the ovaries revealed high levels of pre-ovulatory follicular atresia, impaired oogenesis, a decrease in the oocyte vitellogenic diameter and other lesions, such as fibrosis, vacuolation and melano-macrophagic centers. The histopathology of the liver revealed the presence of necrosis, hypertrophic hepatocytes, foci of vacuolation, glycogen depletion and hemosiderin. An assessment of the general health of the fish indicated that all of the sampled fish from the polluted sites were in poorer health compared with those from the reference site but that the African catfish appeared much more affected than the Guinean tilapia, regardless of the sex and season. In conclusion, the overall results indicated that agricultural pesticides significantly impair the endocrine regulation of fish living in the Beninese cotton basin and that this would most likely be one of the causes of the severe damage observed in the liver and gonads and the reduced health condition.

The synergistic antitumor effects of all-trans retinoic acid and C-phycocyanin on the lung cancer A549 cells in vitro and in vivo

The anticancer effects and mechanism of all-trans retinoic acid (ATRA), C-phycocyanin (C-PC) or ATRA+C-PC on the growth of A549 cells were studied in in vitro and in vivo experiments. The effects of C-PC and ATRA on the growth of A549 cells were determined. The expression of CDK-4 and caspase-3, and the cellular apoptosis levels were detected. The tumor model was established by subcutaneous injection of A549 cells to the left axilla of the NU/NU mice. The weights of tumor and the spleen were tested. The viabilities of T-cells and spleen cells, TNF levels, the expression of Bcl-2 protein and Cyclin D1 gene were examined. Results showed both C-PC and ATRA could inhibit the growth of tumor cells in vivo and in vitro. ATRA+C-PC cooperatively showed a higher antitumor activity. The dosage of ATRA was reduced when it was administered with C-PC together, and the toxicity was reduced as well. ATRA+C-PC could decrease CDK-4 but increase caspase-3 protein expression level and induce cell apoptosis. ATRA alone could lower the activities of T lymphocytes and spleen weights, but the combination with C-PC could effectively promote viability of T cells and spleen. C-PC+ATRA could up-regulate TNF, and down-regulate Bcl-2 and Cyclin D1 gene. The combination might inhibit tumor growth by inhibiting the progress of cell cycle, inducing cell apoptosis and enhancing the body immunity.

Pesticides used in cotton production affect reproductive development, endocrine regulation, liver status and offspring fitness in African catfish Clarias gariepinus (Burchell, 1822)

We exposed African catfish Clarias gariepinus from embryo-larvae stage to adult stage (13 months old, BW) to chronic doses of Tihan 175 O-TEQ and endosulfan (Thionex) and assessed the impact of this exposure on endocrine regulation, liver status and offspring fitness. Endosulfan exposure caused a significant increase in plasma estradiol-17β (E2) and decreased plasma testosterone (T) but not 11 ketotestosterone (11-KT). Tihan decreased significantly plasma E2 and 11-KT, but not T. Endosulfan doses altered gonad histology and induced high proportions (18–30% of males) of ovotestis in males and follicular atretic oocytes in females, indicating occurrence of feminization in fish. Tihan also altered gonad histology but only one case of ovotestis was observed at the highest dose. Presence of foam cells in lobular lumen, fibrosis, necrosis, and immature cells released in lobular lumen were found in male gonads and melano-macrophage centers (MMCs), necrosis, fibrosis and vacuolation were observed in female gonads. Fish livers also suffered injuries such as MMCs, necrosis, fibrosis, vacuolation, dilatation of sinusoids, and nuclear pleomorphism. Chronic Tihan and Thionex exposures decreased fertilization rate, hatching rate, ova and larval weight, as well as larval resistance to osmotic choc. They also delayed hatching and increased abnormalities in the F1 generation, all these indicators suggesting transgenerational effects of these compounds.

p53 dependent apoptotic cell death induces embryonic malformation in Carassius auratus under chronic hypoxia

Hypoxia is a global phenomenon affecting recruitment as well as the embryonic development of aquatic fauna. The present study depicts hypoxia induced disruption of the intrinsic pathway of programmed cell death (PCD), leading to embryonic malformation in the goldfish, Carrasius auratus. Constant hypoxia induced the early expression of pro-apoptotic/tumor suppressor p53 and concomitant expression of the cell death molecule, caspase-3, leading to high level of DNA damage and cell death in hypoxic embryos, as compared to normoxic ones. As a result, the former showed delayed 4 and 64 celled stages and a delay in appearance of epiboly stage. Expression of p53 efficiently switched off expression of the anti-apoptotic Bcl-2 during the initial 12 hours post fertilization (hpf) and caused embryonic cell death. However, after 12 hours, simultaneous downregulation of p53 and Caspase-3 and exponential increase of Bcl-2, caused uncontrolled cell proliferation and prevented essential programmed cell death (PCD), ultimately resulting in significant (p<0.05) embryonic malformation up to 144 hpf. Evidences suggest that uncontrolled cell proliferation after 12 hpf may have been due to downregulation of p53 abundance, which in turn has an influence on upregulation of anti-apoptotic Bcl-2. Therefore, we have been able to show for the first time and propose that hypoxia induced downregulation of p53 beyond 12 hpf, disrupts PCD and leads to failure in normal differentiation, causing malformation in gold fish embryos.

Molecular mechanism of inhibitory effects of C-phycocyanin combined with all-trans-retinoic acid on the growth of HeLa cells in vitro

We studied the effects of all-trans-retinoic acid (ATRA), C-phycocyanin (C-PC), or ATRA+C-PC on the growth of cervical cells (HeLa cells), cell cycle distribution, and apoptosis. The anticancer mechanism of the drug combination was revealed. MTT assay was adopted to determine the effects of C-PC and ATRA on the growth of HeLa cells. The expression quantities of cyclin-dependent kinase (CDK) 4, cyclin D1, Bcl-2, caspase-3, and CD59 were determined by in situ hybridization, immunofluorescence, immunohistochemistry staining, Western blot, and RT-PCR. TUNEL assay was adopted to determine the cellular apoptosis levels. Both C-PC and ATRA could inhibit the growth of HeLa cells, and the combination of ATRA+C-PC functioned cooperatively to induce apoptosis in HeLa cells. The dosage of ATRA was reduced when it cooperated with C-PC to reduce the toxicity. ATRA treated with C-PC could induce more cell cycle arrests than the single drug used by decrease in cyclin D1 and CDK4 expression. The combination of the two drugs could upregulate caspase-3 and downregulate the Bcl-2 gene and induce cell apoptosis. Moreover, the combination therapy has an important immunological significance in decreased expression of the CD59 protein. Singly, C-PC or ATRA could inhibit the growth of HeLa cells, and the effects of treatment were further enhanced in the combination group. In combination with C-PC, the dosage of ATRA was effectively reduced. The C-PC + ATRA combination might take effect by inhibiting the progress of the cell cycle, inducing cell apoptosis and promoting complement-mediated cytolysis.

Induction of apoptosis in testis of the marine teleost mummichog Fundulus heteroclitus after in vivo exposure to the antifouling biocide 4,5-dichloro-2-n-octyl-3(2H)-isothiazolone (Sea-Nine 211)

4,5-dichloro-2-n-octyl-3(2H)-isothiazolone (Sea-Nine 211) has been widely used as an effective antifouling biocide. However, little is known about its reproductive toxicity in fish. Here we investigated testicular toxicity in a marine teleost, the mummichog Fundulus heteroclitus, after exposure to Sea-Nine 211 for 28 d. Although Sea-Nine 211 exposure did not affect germ cell proliferation in testis, terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick-end labeling revealed that the number of apoptotic spermatocytes was increased in the 1.0- and 3.0-μg L(-1) groups, and significant differences emerged between the 1.0-μg L(-1) group and control groups. Immunohistochemistry showed that the numbers of cysts expressing caspases 2, 3, 6, and 8 (apoptosis-associated proteins) were significantly increased in the 1.0-μg L(-1) group, whereas the signal intensity of an anti-apoptotic protein Bcl-xL was reduced in a dose-dependent manner. Moreover, the number of cysts positive for neuronal nitric oxide synthase was twofold higher in the 1.0-μg L(-1) group than in the control groups. These results suggest that long-term exposure to Sea-Nine 211 induces apoptosis in the testicular germ cells of mummichogs via a caspase-dependent pathway and that oxidative stress via nitric oxide synthesized by neuronal nitric oxide synthase is involved in this induction.