Polyglucosan Molecules Induce Mitochondrial Impairment and Apoptosis in Germ Cells Without Affecting the Integrity and Functionality of Sertoli Cells

Dibutyl phthalate disrupts energy metabolism and morphology in the gills and induces hepatotoxicity in zebrafish

This study investigated the acute effects of dibutyl phthalate (DBP) exposure on energy metabolism and gill histology in zebrafish (Danio rerio). The in vitro incubation of gill tissue with 10 μM DBP for 60 min altered tissue energy supply, as shown by decreased lactate content and lactate dehydrogenase (LDH) activity. Higher concentrations of DBP (100 μM and 1 mM) increased lactate content and LDH activity; however, they blocked glucose uptake, depleted the glycogen content in cellular stores, and induced injury to the gills, as measured by LDH release to the extracellular medium. In addition, in vivo exposure of fish to 1 pM DBP for 12 h induced liver damage by increasing alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) activities. Gill histology indicated hyperemia, lamellar fusion, lamellar telangiectasis, and necrosis. Data indicate that acute exposure of zebrafish gills to the higher DBP concentrations studied induces anaerobic cellular activity and high lactate production, causing gill damage, diminishing cell viability, and incurring liver dysfunction.

Temperature, but not excess of glycogen, regulates "in vitro" AMPK activity in muscle samples of steer carcasses

Postmortem muscle temperature affects the rate of pH decline in a linear manner from 37.5°C to 0-2°C. The pH decline is correlated with the enzymatic degradation of glycogen to lactate and this process includes the metabolic coupling between glycogenolysis and glycolysis, and that are strongly upregulated by the AMPK. In this study, we used 12 samples previously characterized by have different muscle glycogen concentration, lactate and AMPK activity, selected from 38 steers that produced high final pH (>5.9) and normal final pH (<5.8) carcasses at 24 h postmortem. Moreover, we evaluated changes in the AMPK activity in samples from both categories incubated at 37, 25, 17 and 5°C and supplemented with exogenous glycogen. Finally, we analysed if there were structural differences between polymers from both categories. Our results showed that "in vitro" enzymatic AMPK activity evaluated at both 0.5 or 24 h was greater in samples from normal then high pH categories (p <0.01), and in all temperature of incubation analysed (17, 25 and 37°C). For other hand, a greater AMPK activity were obtained in samples incubated at 17 that 25 or 37°C, in normal carcasses at both 0.5 or 24 h (p < 0.01), as also in samples from carcasses categorized as high pH, but at 24 h (p < 0.05). Interestingly, AMPK activity was totally abolished at 5°C, independent of final pH category of carcasses, and was confirmed that the incubation temperature at which the maximum activity was obtained (p < 0.01), at least in carcasses with a normal pH is at 17°C. The enzymatic AMPK activity did not change in relation to excess glycogen (p > 0.05) and we did not detect structural differences in the polymers present in samples from both categories (p > 0.05), suggesting that postmortem AMPK activity may be highly sensitive to temperature and not to in vitro changes in glycogen concentration (p > 0.05). Our results allow concluding that normal concentrations of muscle glycogen immediately at the time of slaughter (0.5 h) and an adequate cooling managing of carcasses are relevant to let an efficient glycogenolytic/glycolytic flow required for lactate accumulation and pH decline, through the postmortem AMPK signalling pathway.

Melatonin Ameliorates Busulfan-Induced Spermatogonial Stem Cell Oxidative Apoptosis in Mouse Testes

AIMS

Many men endure immunosuppressive or anticancer treatments that contain alkylating agents before the age of sexual maturity, especially the increasing number of preadolescent males who undergo busulfan treatment for myeloablative conditioning before hematopoietic stem cell transplantation. Before sperm production, there are no sperm available for cryopreservation. Thus, it is necessary to identify a solution to ameliorate the busulfan-induced damage of spermatogonial stem cells (SSCs).

RESULTS

In this study, we demonstrated that melatonin relieved the previously described SSC loss and apoptosis in mouse testes. Melatonin increased the expression of manganese superoxide dismutase (MnSOD), which regulated the production of busulfan-induced reactive oxygen species (ROS). Moreover, melatonin promoted sirtuin type 1 (SIRT1) expression. SIRT1 participated in the deacetylation of p53, which promotes p53 ubiquitin degradation. Decreased concentrations of deacetylated p53 resulted in spermatogonial cell resistance to apoptosis. Acute T cell leukemia cell assay demonstrated that melatonin does not affect busulfan-induced cancer cell apoptosis and ROS.

INNOVATION

The current evidence suggests that melatonin may alleviate the side effects of alkylating drugs, such as busulfan.

CONCLUSION

Melatonin promoted MnSOD and SIRT1 expression, which successfully ameliorated busulfan-induced SSC apoptosis caused by high concentrations of ROS and p53. Antioxid. Redox Signal. 28, 385-400.

Is Type 2 Diabetes a Glycogen Storage Disease of Pancreatic β Cells?

Elevated plasma glucose leads to pancreatic β cell dysfunction and death in type 2 diabetes. Glycogen accumulation, due to impaired metabolism, contributes to this "glucotoxicity" via dysregulated biochemical pathways promoting β cell dysfunction. Here, we review emerging data, and re-examine published findings, on the role of glycogen in β cells in normoglycemia and in diabetes.

Tricholoma matsutake Aqueous Extract Induces Hepatocellular Carcinoma Cell Apoptosis via Caspase-Dependent Mitochondrial Pathway

Tricholoma matsutake, one of widely accepted functional mushrooms, possesses various pharmacological activities, and its antitumor effect has become an important research point. Our study aims to evaluate the cytotoxicity activities of T. matsutake aqueous extract (TM) in HepG2 and SMMC-7721 cells. In in vitro experiments, TM strikingly reduced cell viability, promoted cell apoptosis, inhibited cell migration ability, induced excessive generation of ROS, and caused caspases cascade and mitochondrial membrane potential dissipation in hepatocellular carcinoma cells. In in vivo experiments, 14-day TM treatment strongly suppressed tumor growth in HepG2 and SMMC-7721-xenografted nude mice without influence on their body weights and liver function. Furthermore, TM increased the levels of cleaved poly-ADP-ribose polymerase (PARP), Bad, and Bax and reduced the expressions of B-cell lymphoma 2 (Bcl-2) in treated cells and tumor tissues. All aforementioned results suggest that caspase-dependent mitochondrial apoptotic pathways are involved in TM-mediated antihepatocellular carcinoma.

Tricholoma matsutake Aqueous Extract Induces Hepatocellular Carcinoma Cell Apoptosis via Caspase-Dependent Mitochondrial Pathway

Tricholoma matsutake, one of widely accepted functional mushrooms, possesses various pharmacological activities, and its antitumor effect has become an important research point. Our study aims to evaluate the cytotoxicity activities of T. matsutake aqueous extract (TM) in HepG2 and SMMC-7721 cells. In in vitro experiments, TM strikingly reduced cell viability, promoted cell apoptosis, inhibited cell migration ability, induced excessive generation of ROS, and caused caspases cascade and mitochondrial membrane potential dissipation in hepatocellular carcinoma cells. In in vivo experiments, 14-day TM treatment strongly suppressed tumor growth in HepG2 and SMMC-7721-xenografted nude mice without influence on their body weights and liver function. Furthermore, TM increased the levels of cleaved poly-ADP-ribose polymerase (PARP), Bad, and Bax and reduced the expressions of B-cell lymphoma 2 (Bcl-2) in treated cells and tumor tissues. All aforementioned results suggest that caspase-dependent mitochondrial apoptotic pathways are involved in TM-mediated antihepatocellular carcinoma.