Involvement of ERK1/2 and p38 MAPK in up-regulation of 14-3-3 protein induced by hydrogen peroxide preconditioning in PC12 cells

Protective effects of trehalose on frozen-thawed ovarian granulosa cells of cattle

In this study, trehalose was investigated for its cryoprotective effects on ovarian granulosa cells (bGCs) of cattle. Five concentrations of trehalose at 0, 0.2, 0.4, 0.6 and 0.8 mol/L were added to the cryopreservation medium of bGCs, and the effects on the quality of frozen-thawed bGCs were assessed. The results indicate that the use of cryopreservation medium containing 0.2 and 0.4 mol/L of trehalose resulted in a greater rate of bGC viability compared to those of other groups (P<0.05). Culturing with trehalose at 0.2 and 0.4 mol/L increased 17β- estradiol (E₂)and decreased progesterone (P₄)production (P < 0.05) in post-thawed bGCs. Compared with the control group, the intracellular Ca²⁺ concentrations of frozen-thawed bGCs were less in all treatment groups (P<0.05), and the least Ca²⁺ concentration was observed in the group containing 0.4 mol/L trehalose. The plasma membrane potentials of frozen-thawed bGCs were greater in the groups with 0.2 and 0.4 mol/L trehalose, and the group treated with 0.4 mol/L trehalose had the greatest membrane potential in comparison to other groups (P < 0.05). The relative abundance of the CYP19 mRNA in frozen-thawed bGCs was greater in the groups containing 0.2, 0.4 and 0.6 mol/L trehalose, and relative abundances of FSHR and BCL2 mRNA were greater in the group of bGCs treated with 0.2 mol/L trehalose (P<0.05). Trehalose treatment at 0.4, 0.6 and 0.8 mol/L had an inhibitory effect on BAX gene transcription in frozen-thawed bGCs (P<0.05). In summary, trehalose exhibited a greater cryoprotective effect on bGCs than basic cryopreservation medium.

Ischemia preconditioning protects astrocytes from ischemic injury through 14-3-3γ

Stroke is a leading cause of death and disability, and new strategies are required to reduce neuronal injury and improve prognosis. Ischemia preconditioning (IPC) is an intrinsic phenomenon that protects cells from subsequent ischemic injury and might provide promising mechanisms for clinical treatment. In this study, primary astrocytes exhibited significantly less cell death than control when exposed to different durations of IPC (15, 30, 60, or 120 min). A 15-min duration was the most effective IPC to protect astrocytes from 8-hr-ischemia injury. The protective mechanisms of IPC involve the upregulation of protective proteins, including 14-3-3γ, and attenuation of malondialdehyde (MDA) content and ATP depletion. 14-3-3γ is an antiapoptotic intracellular protein that was significantly upregulated for up to 84 hr after IPC. In addition, IPC promoted activation of the c-Jun N-terminal kinase (JNK), extracellular signal-related kinase (ERK)-1/2, p38, and protein kinase B (Akt) signaling pathways. When JNK was specifically inhibited with SP600125, the upregulation of 14-3-3γ induced by IPC was almost completely abolished; however, there was no effect on ATP or MDA levels. This suggests that, even though both energy preservation and 14-3-3γ up-regulation were turned on by IPC, they were controlled by different pathways. The ERK1/2, p38, and Akt signaling pathways were not involved in the 14-3-3γ upregulation and energy preservation. These results indicate that IPC could protect astrocytes from ischemia injury by inducing 14-3-3γ and by alleviating energy depletion through different pathways, suggesting multiple protection of IPC and providing new insights into potential stroke therapies.

Antioxidation of decellularized stem cell matrix promotes human synovium-derived stem cell-based chondrogenesis

Clinical treatment of cartilage defects is challenging due to concomitant post-traumatic joint inflammation. This study was to demonstrate that the antioxidant ability of human adult synovium-derived stem cells (SDSCs) could be enhanced by ex vivo expansion on a decellularized stem cell matrix (DSCM). Microarray was used to evaluate oxidative, antioxidative, and chondrogenic status in SDSCs after expansion on the DSCM and induction in the chondrogenic medium. Hydrogen peroxide (H2O2) was added to create oxidative stress in either expanded SDSCs or chondrogenically induced premature pellets. The effect of H2O2 on SDSC proliferation was evaluated using flow cytometry. Chondrogenic differentiation of expanded SDSCs was evaluated using histology, immunostaining, biochemical analysis, and real-time polymerase chain reaction. Mitogen-activated protein kinase signaling pathways and p21 were compared in the DSCM and plastic-flask-expanded SDSCs with or without H2O2 treatment. We found that expansion on the DSCM upregulated antioxidative gene levels and chondrogenic potential in human SDSCs (hSDSCs), retarded the decrease in the cell number and the increase in apoptosis, and rendered SDSCs resistant to cell-cycle G1 arrest resulting from H2O2 treatment. Treatment with 0.05 mM H2O2 during cell expansion yielded pellets with increased chondrogenic differentiation; treatment in premature SDSC pellets showed that the DSCM-expanded cells had a robust resistance to H2O2-induced oxidative stress. Extracellular signal-regulated kinases 1 and 2 and p38 were positively involved in antioxidative and chondrogenic potential in SDSCs expanded on the DSCM in which p21 was downregulated. DSCM could be a promising cell expansion system to provide a large number of high-quality hSDSCs for cartilage regeneration in a harsh joint environment.

Protective effect of 7-difluoromethoxy-5,4'-Di-hydroxyl isoflavone against the damage induced by glutamate in PC12 cells

7-difluoromethoxy-5,4'-Di-hydroxyl isoflavone (dFGEN), prepared by the difluoromethylation of genistein, is an active chemical entity. In this study, our main purpose was to investigate whether dFGEN had an effect on glutamate-induced apoptosis in cultured PC12 cells. The PC12 cells were treated with different glutamate concentrations for 24 h in vitro. The PC12 cells impaired by glutamate were used as the cell model of excitability. Cells were incubated for 30 min with genistein, dFGEN, vitamin E, and exposed to 10 mM glutamate for 24 h. Cell morphology was observed by light microscopy. The growth and proliferation of PC12 cells were detected by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Cell apoptosis was determined by flow cytome-try (FCM) with propidium iodide (PI) staining. The activity of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and the content of malondialdelyde (MDA) were measured by kits, respectively. Acridine orange (AO) staining was used to detect characteristics of cell apoptosis. When PC12 cells were incubated with glutamate for 24 h, cells appeared to have significant changes in shape. The cellular viability was reduced and the apoptotic rate was increased. The levels of LDH and the content of MDA were increased. The activity of SOD was decreased. After PC12 cells were pretreated with dFGEN, dFGEN significantly improved cell morphology, cell growth and proliferation, suppressed apoptosis of cells, reduced the release of LDH, improving SOD activity and decreased MDA content in a concentration-dependent manner. AO staining displayed that apoptosis was decreased. These results suggested that dFGEN has a protective effect against glutamate-induced damage in PC12 cells. dFGEN seemed to have a better protective effect than the lead compound genistein in a concentration-dependent manner. The mechanism of protective effect of dFGEN may be mainly related to its antioxidative activity.

Mechanisms of cellular adaptation to quantum dots--the role of glutathione and transcription factor EB

Cellular adaptation is the dynamic response of a cell to adverse changes in its intra/extra cellular environment. The aims of this study were to investigate the role of: (i) the glutathione antioxidant system, and (ii) the transcription factor EB (TFEB), a newly revealed master regulator of lysosome biogenesis, in cellular adaptation to nanoparticle-induced oxidative stress. Intracellular concentrations of glutathione species and activation of TFEB were assessed in rat pheochromocytoma (PC12) cells following treatment with uncapped CdTe quantum dots (QDs), using biochemical, live cell fluorescence and immunocytochemical techniques. Exposure to toxic concentrations of QDs resulted in a significant enhancement of intracellular glutathione concentrations, redistribution of glutathione species and a progressive translocation and activation of TFEB. These changes were associated with an enlargement of the cellular lysosomal compartment. Together, these processes appear to have an adaptive character, and thereby participate in the adaptive cellular response to toxic nanoparticles.

Insufficient activity of MAPK pathway is a key monitor of Kidney-Yang Deficiency Syndrome

OBJECTIVE

To explore the genetic characteristics and molecular regulator of Kidney-Yang Deficiency Syndrome (KDS).

DESIGN

A typical KDS family was collected using a questionnaire of cold feeling and a 40-item scoring table of KDS based on Traditional Chinese Medicine (TCM), by single-blind method repeated annually over three years. Their transcriptomes were assayed by microarray and validated by RT-PCR and ELISA. Simultaneously, 10 healthy volunteers were recruited as controls and the same protocols were performed.

RESULTS

This typical KDS family has 35 members, of whom 11 were evaluated as having severe KDS and 6 as having common KDS. Results of the cDNA microarray revealed that there were 420 genes/expressed sequence tags differentially expressed in KDS transcriptomes, indicating a global functional impairment in the mass-energy-information carrying network of KDS patients, involving energy metabolism, signal transduction, development, cell cycle, and immunity. Pathway analysis by gene set enrichment assay (GSEA) and other tools demonstrated that mitogenic activated protein kinase (MAPK) is among the most insufficiently activated pathways, while the oxidative phosphorylation and glycolysis/gluconeogenesis pathways, the two main pathways relevant to ATP synthesis, were among the most excessively activated pathways in KDS patients. Results of RT-PCR and ELISA confirmed the status of insufficient activity of the MAPK pathway.

CONCLUSION

KDS patients undergo overall attenuated functions in the mass-energy-information carrying network. The marked low level of energy output in KDS may be primarily attributed to the insufficient activity of the MAPK pathway, which may be a key monitor for the abnormal energy metabolism and other impaired activities in KDS.