Bax modulates neuronal survival while p53 is unaltered after Cytochrome C induced oxidative stress in the adult olfactory bulb in vivo

The physiological response of oriental river prawn Macrobrachium nipponense to starvation-induced stress

Environmental stresses play critical roles in the physiology of crustaceans. Food deprivation is an important environmental factor and a regular occurrence in both natural aquatic habitats and artificial ponds. However, the underlying physiological response mechanisms to starvation-caused stress in crustaceans are yet to be established. In the present study, the hepatopancreas tissue of Macrobrachium nipponense was transcriptome analyzed and examined for starvation effects on oxidative stress, DNA damage, autophagy, and apoptosis across four fasting stages (0 (control group), 7, 14, and 21 days). These results indicated that a ROS-mediated regulatory mechanism is critical to the entire fasting process. At the initial stage of starvation (fasting 0 d ~ 7 d), ROS concentration increased gradually, activating antioxidant enzymes to protect the cellular machinery from the detrimental effects of oxidative stress triggered by starvation-induced stress. ROS content production (hydrogen peroxide and superoxide anion) then rose continuously with prolonged starvation (fasting 7 d ~ 14 d), reaching peak levels and resulting in autophagy in hepatopancreas cells. During the final stages of starvation (fasting 14 d ~ 21 d), excessive ROS induced DNA damage and cell apoptosis. Furthermore, autophagolysosomes and apoptosis body were further identified with transmission electron microscopy. These findings lay a foundation for further scrutiny of the molecular mechanisms combating starvation-generated stress in M. nipponense and provide fishermen with the theoretical guidance for adopting fasting strategies in M. nipponense aquaculture.

ROS-mediated physiological activities and apoptotic effect on the survival of abalone (Haliotis discus hannai) under homoyessotoxin and ammonia stresses

Serious dinoflagellate blooms produce homoyessotoxin (homo-YTX) and ammonia (NH3-N) in eutrophic seawaters, posing threats to the healthy development of the mariculture industry. This study aimed to explore the toxicity mechanism of homo-YTX and NH3-N on the survival of abalone, which is important for the ecotoxicological research and cultivation of shellfish. The economy abalone Haliotis discus hannai was placed in homo-YTX (0, 2, 5, and 10 μg L-1) and NH3-N (0, 1.08, and 3.16 mg L-1) and a mixture of the two compounds to determine the survival rate (S), antioxidative responses, physiological activities, and apoptosis of abalone. Results show that the combination of homo-YTX and NH3-N increased the reactive oxygen species level, the malondialdehyde content, and the expression level of BCL2-associated X but decreased S; the activities of superoxide dismutase, catalase, adenosine triphosphatase, glutamic-pyruvic transaminase, xanthine oxidase, lactate dehydrogenase, and lysozyme; and the expression level of B-cell lymphoma-2. The activities of alkaline phosphatase and acid phosphatase in 10 μg L-1 of homo-YTX and 3.16 mg L-1 of NH3-N solutions and in the mixture of the two toxicants decreased. The caspase3 expression level was downregulated in 10 μg L-1 of homo-YTX. These results suggest that homo-YTX and NH3-N enhanced the oxidative stress and lipid peroxidation reactions, inhibited the energy supply, disrupted the metabolic and immune physiological functions, and activated apoptosis in the gills of abalone. ROS-mediated physiological activities and apoptosis were among the potential toxicity mechanisms of the interactive effects of homo-YTX and NH3-N on abalone.

BDE-209-induced genotoxicity, intestinal damage and intestinal microbiota dysbiosis in zebrafish (Danio Rerio)

The environmental presence of polybrominated diphenyl ethers (PBDEs) is ubiquitous due to their wide use as brominated flame retardants in industrial products. As a common congener of PBDEs, decabromodiphenyl ether (BDE-209) can pose a health risk to animals as well as humans. However, to date, few studies have explored BDE-209's toxic effects on the intestinal tract, and its relevant mechanism of toxicity has not been elucidated. In this study, adult male zebrafish were exposed to BDE-209 at 6 μg/L, 60 μg/L and 600 μg/L for 28 days, and intestinal tissue and microbial samples were collected for analysis to reveal the underlying toxic mechanisms. Transcriptome sequencing results demonstrated a dose-dependent pattern of substantial gene differential expression in the group exposed to BDE-209, and the differentially expressed genes were mainly concentrated in pathways related to protein synthesis and processing, redox reaction, and steroid and lipid metabolism. In addition, BDE-209 exposure caused damage to intestinal structure and barrier function, and promoted intestinal oxidative stress, inflammatory response, apoptosis and steroid and lipid metabolism disorders. Mechanistically, BDE-209 induced intestinal inflammation by increasing the levels of TNF-α and IL-1β and activating the NFκB signaling pathway, and might induce apoptosis through the p53-Bax/Bcl2-Caspase3 pathway. BDE-209 also significantly inhibited the gene expression of rate-limiting enzymes such as Sqle and 3βhsd (p < 0.05) to inhibit cholesterol synthesis. In addition, BDE-209 induced lipid metabolism disorders through the mTOR/PPARγ/RXRα pathway. 16S rRNA sequencing results showed that BDE-209 stress reduced the richness and diversity of intestinal microbiota, and reduced the abundance of probiotics (e.g., Bifidobacterium and Faecalibacterium). Overall, the results of this study help to clarify the intestinal response mechanism of BDE-209 exposure, and provide a basis for evaluating the health risks of BDE-209 in animals.

State of the Art of Pharmacological Activators of p53 in Ocular Malignancies

The pivotal role of p53 in the regulation of a vast array of cellular functions has been the subject of extensive research. The biological activity of p53 is not strictly limited to cell cycle arrest but also includes the regulation of homeostasis, DNA repair, apoptosis, and senescence. Thus, mutations in the p53 gene with loss of function represent one of the major mechanisms for cancer development. As expected, due to its key role, p53 is expressed throughout the human body including the eye. Specifically, altered p53 signaling pathways have been implicated in the development of conjunctival and corneal tumors, retinoblastoma, uveal melanoma, and intraocular melanoma. As non-selective cancer chemotherapies as well as ionizing radiation can be associated with either poor efficacy or dose-limiting toxicities in the eye, reconstitution of the p53 signaling pathway currently represents an attractive target for cancer therapy. The present review discusses the role of p53 in the pathogenesis of these ocular tumors and outlines the various pharmacological activators of p53 that are currently under investigation for the treatment of ocular malignancies.

The protective effects of selenium on chronic ammonia toxicity in yellow catfish (Pelteobagrus fulvidraco)

Ammonia is toxic to most fish, and its negative effects can be eliminated by nutritional manipulation. In this study, triplicate groups of yellow catfish (0.58 ± 0.03 g) were fed diets supplemented with 0, 0.30 and 0.60 mg selenium (Se) kg^-1 diet for 56 days under three ammonia contents (0.00, 5.70 and 11.40 mg L^-1 total ammonia nitrogen). The results showed that ammonia toxicity could affects growth (weight gain, feed efficiency ratio, Se contents in muscle and whole body declined) and survival, leads to oxidative stress (total antioxidant capacity, superoxide dismutase, catalase and glutathione peroxidase activities declined and malondialdehyde accumulation), immunosuppression (lysozyme activity, 50% hemolytic complement, immunoglobulin M, respiratory burst and phagocytic index declined) and cytokines release (TNF, IL 1 and IL 8 elevated), induces up-regulation of antioxidant enzymes (Cu/Zn-SOD, Mn-SOD, CAT and GPx), cytokines (TNFα, IL 1 and IL 8) and pro-apoptotic genes (p53, Bax, Cytochrome c, Caspase 3 and Caspase 9) transcription, and down-regulation of anti-apoptotic gene Bcl2 transcription. The dietary Se supplementation could mitigate the adverse effect of ammonia poisoning on fish growth, oxidative damage, immunosuppression and apoptotic.

Effect of nitrite exposure on haematological status, oxidative stress, immune response and apoptosis in yellow catfish (Pelteobagrus fulvidraco)

Nitrite can cause fishes poisoning. This study evaluated the effects of nitrite exposure on haematological status, ion concentration, antioxidant enzyme activity, immune response, cytokine release and apoptosis in yellow catfish. In this study, yellow catfish were exposed to three levels of nitrite (0, 3.00 and 30.00 mg L^-1) for 96 h. The results showed that nitrite poisoning could lead to blood deterioration (red blood cell and hemoglobin reduced; white blood cell and methemoglobin elevated), ion imbalance (Na⁺ and Cl^- declined; K⁺ elevated), oxidative stress (total antioxidant capacity, superoxide dismutase, catalase and glutathione peroxidase activities declined; malondialdehyde accumulation), immunosuppression (lysozyme activity, 50% hemolytic complement, immunoglobulin M, respiratory burst and phagocytic index declined) and cytokines release (TNF, IL 1 and IL 8 elevated). In addition, nitrite poisoning could induce up-regulation of antioxidant enzymes (Cu/Zn-SOD, Mn-SOD, CAT and GPx), cytokines (TNF, IL 1 and IL 8) and apoptosis (P53, Bax, Cytochrome c, Caspase 3, Caspase 9, ERK and JNK) genes transcription. This study suggesting that the nitrite exposure triggers blood deterioration, disrupts the ionic homeostasis, induces oxidative stress, immunosuppression, inflammation and apoptosis in yellow catfish.

Ammonia toxicity in the yellow catfish (Pelteobagrus fulvidraco): The mechanistic insight from physiological detoxification to poisoning

Ammonia is toxic to fishes. Different fish have different defense strategies against ammonia, so the mechanism of ammonia poisoning is different. In this study, yellow catfish were exposed to three levels of ammonia (0, 5.70 and 57.00 mg L^-1) for 96 h. The results showed that ammonia poisoning could lead to free amino acid imbalance (ornithine and citrulline contents declined; arginine content elevated), urea cycle enzymes deficiency (carbamyl phosphate synthetase and arginase contents declined), oxidative stress (superoxide dismutase, catalase and glutathione peroxidase activities declined), immunosuppression (lysozyme activity, 50% hemolytic complement and total immunoglobulin contents and phagocytic index declined) and cytokines release (TNF, IL 1 and IL 8 contents elevated). In addition, ammonia poisoning could induce up-regulation of antioxidant enzymes (Cu/Zn-SOD, Mn-SOD, CAT and GPx), cytokines (TNFα, IL 1 and IL 8) and apoptosis (p53, Bax, cytochrome c, Caspase 3 and Caspase 9) genes transcription. This study suggesting that the urea cycle and glutamine synthesis both were involved in the ammonia detoxification of yellow catfish, and the immunosuppression, inflammation and apoptotic induced by ammonia poisoning in yellow catfish are related to oxidative stress.

Effects of acute ammonia toxicity on oxidative stress, DNA damage and apoptosis in digestive gland and gill of Asian clam (Corbicula fluminea)

Ammonia is one of the major pollutants associated with the main river basins due to ammonification of uneaten food and animal excretion, which usually brings detrimental health effects to aquatic invertebrate. However, the mechanisms of ammonia toxicity in aquatic invertebrate have rarely been reported. In this study, C. fluminea was exposed to different levels of ammonia (control group, 10 mg/L, and 25 mg/L) for 24 h and 48 h, and digestive gland and gill were collected to explore toxic effects on oxidative stress, DNA damage and apoptosis under ammonia stress. The results showed that ammonia poisoning could increase the activity of oxidative stress enzyme (SOD and CAT), inducing differentially expressed genes (DRAM2, GADD45, P53, BAX, BCL2, CASP8, CASP9, CASP3, HSP70 and HSP90) and different cytokines (IL-1 beta, IL-8, IL-17 and TNF-alpha) of DNA damage and apoptosis. The difference of toxic effects induced by ammonia among digestive gland and gill were also observed by real-time PCR and TUNEL staining. Our results will be helpful to understand the mechanism of aquatic toxicology induced by ammonia in C. fluminea.

Jobelyn® Supplement Lowered Neuronal Degeneration: Significance of Altered p53 and ɤ-Enolase Protein Expressions in Prefrontal Cortex of Rat Exposed to Ethanol

BACKGROUND

Alcohol-induced neurodegeneration, a consequence of chronic ethanol exposure, is a neuroadaptation that drives the progression of alcohol use disorder (AUD). Unfortunately, conventional drugs for AUDs do not prevent neurodegeneration as part of their pharmacological repertoire. Multimodal neuroprotective therapeutic agents are hypothesized to have high therapeutic utility in the treatment of central nervous system. Interestingly, nutraceuticals by nature are multimodal in mechanisms of action.

PURPOSE

This study examined the neuroprotective potential of Jobelyn in prefrontal cortex (PFC) of a binge-alcohol rat model of AUD.

METHODS

Three groups of rats were fed thrice daily through an orogastric tube with 5 g/kg ethanol (25% w/v), 5 g/kg ethanol (25% w/v) plus Jobelyn (4 mg/kg body weight), and 5 g/kg of a nutritionally complete diet (50% v/v), respectively. Cytoarchitectural study of the PFC was done in slides stained with haematoxylin and eosin. Immunohistochemical analyses were performed with mice monoclonal anti-p53 and anti-neuron specific enolase (NSE) antibodies to detect the degree of apoptosis and necrosis in the PFC. In addition, the degree of tissue damage and the level of lipid peroxidation were evaluated.

RESULTS

Jobelyn supplementation significantly lowered the levels of histologic and biochemical indices of neurodegeneration, and caused an increased expression of p53 protein and a decreased expression of NSE immunoreactivity (NSE-IR).

CONCLUSIONS

Jobelyn supplementation ameliorates neurodegeneration in the PFC of AUD rats by reducing the oxidative stress, reducing the NSE-IR, and by increasing the expression of cellular tumor antigen p53 in the cortical neurons.