GSK-3β promotes PA-induced apoptosis through changing β-arrestin 2 nucleus location in H9c2 cardiomyocytes

Zearalenone-Promoted Follicle Growth through Modulation of Wnt-1/β-Catenin Signaling Pathway and Expression of Estrogen Receptor Genes in Ovaries of Postweaning Piglets

Feedstuffs are severely contaminated by zearalenone (ZEA) worldwide. A specific dietary level of ZEA could cause malformations of the reproductive organs of sows, false estrus, decreased litter size, and abortion. However, the underlying mechanisms are still not clear. The objectives of the present study were to assess the effects of ZEA on morphology, distribution, and expression of estrogen receptors (ERα and ERβ) in the ovaries of postweaning piglets. Furthermore, the relationship between ERs/glycogen synthase kinase (GSK)-3β-dependent pathways mediated by ZEA and the Wnt-1/β-catenin signaling pathway was examined. Forty healthy weaning piglets were allocated to the following four treatment groups: piglets fed with basal diet only (control), and ZEA0.5, ZEA1.0, and ZEA1.5, which were fed basal diets supplemented with ZEA at 0.5, 1.0, and 1.5 mg·kg^-1, respectively. Then, the expression of GSK-3β, ERα, ERβ, and Wnt-1/β-catenin were examined histomorphologically and immunohistochemically. Results showed that the proportion of primordial follicles (PrF's) decreased ( p < 0.001) but that of atretic primordial follicles (APFs) increased ( p < 0.001) with increasing dietary ZEA levels. More interestingly, the immunopositivity of ERβ in the ovaries was stronger than that of ERα with the same treatment. The relative mRNA and protein expression levels of ERα, ERβ, Wnt-1, β-catenin, and GSK-3β in the ovaries of postweaning gilts increased linearly ( p < 0.05) as dietary ZEA concentrations increased. Moreover, the accumulation of Wnt-1 and β-catenin in the ovaries indicated that ZEA activated the Wnt-1/β-catenin pathway, mediated by ERs/GSK-3β. Our results strongly suggested that ovarian follicles in the ZEA (0.5-1.5 mg·kg^-1)-treated groups were highly proliferative state, indicating that ZEA promoted ovarian development. The results also suggested that ZEA activates the ERs/GSK-3β-dependent Wnt-1/β-catenin signaling pathway, indicating its important role in accelerating development of the ovaries.

Jujuboside A attenuates norepinephrine-induced apoptosis of H9c2 cardiomyocytes by modulating MAPK and AKT signaling pathways

Cardiomyocyte apoptosis is closely associated with the pathogenesis of heart failure. Jujuboside A (JUA) is a type of saponin isolated from the seeds of Zizyphus jujuba. In traditional Chinese medicine, it is believed that JUA possesses multiple biological effects, including antianxiety, antioxidant and anti‑inflammatory activities. The present study aimed to evaluate the effects of JUA on norepinephrine (NE)‑induced apoptosis of H9c2 cells and to investigate its underlying mechanisms. Rat H9c2 cardiomyocytes were pretreated with JUA and were then exposed to NE as an in vitro model of myocardial apoptosis. A cell viability assay, scanning electron microscopy, transmission electron microscopy, flow cytometry assay, acridine orange/ethidium bromide staining, reverse transcription‑quantitative polymerase chain reaction and western blotting, all revealed that NE induced H9c2 cell apoptosis. The results demonstrated that NE inhibited cell viability, and enhanced cell damage and apoptosis of H9c2 cells. Conversely, pretreatment with JUA was able to reverse NE‑induced decreased cell viability and increased apoptosis. Furthermore, JUA suppressed upregulation of the B‑cell lymphoma 2 (Bcl‑2)‑associated X protein/Bcl‑2 ratio, and inhibited the increased protein expression levels of cleaved caspase‑3 and cleaved caspase‑9 following NE exposure. However, the protein expression levels of cleaved caspase‑12 and cleaved caspase‑8 were not significantly altered following exposure to NE or JUA pretreatment. In addition, in JUA‑pretreated cells, the protein expression levels of phosphorylated (p)‑p38 and p‑c‑Jun N‑terminal kinase were downregulated compared with in NE‑treated cells. Furthermore, JUA regulated the activation of extracellular signal‑regulated kinase (ERK) in NE‑treated cells and significantly increased the expression levels of p‑AKT. Taken together, these data suggested that JUA may protect against NE‑induced apoptosis of cardiomyocytes via modulation of the mitogen‑activated protein kinase and AKT signaling pathways. Therefore, JUA may be considered a potential therapeutic strategy for the treatment of heart disease.