Reactive oxygen species (ROS) play a dual role in mammalian spermatozoa. At high levels, they are detrimental to sperm function since they can promote oxidative stress that produces oxidation of protein, lipids, and sperm DNA. This oxidative damage is associated with male infertility. On the other hand, when ROS are produced at low levels, they participate in the redox signaling necessary for sperm capacitation. Capacitation-associated ROS are produced by the sperm oxidase, whose identity is still elusive, located in the plasma membrane of the spermatozoon. ROS, such as superoxide anion, hydrogen peroxide, nitric oxide, and peroxynitrite, activate protein kinases and inactivate protein phosphatases with the net increase of specific phosphorylation events. Peroxiredoxins (PRDXs), antioxidant enzymes that fight against oxidative stress, regulate redox signaling during capacitation. Among them, PRDX6, which possesses peroxidase and calcium-independent phospholipase A 2 (iPLA 2 ) activities, is the primary regulator of redox signaling and the antioxidant response in human spermatozoa. The lysophosphatidic acid signaling is essential to maintain sperm viability by activating the phosphatidylinositol 3-kinase/protein kinase (PI3K/AKT) pathway, and it is regulated by PRDX6 iPLA 2 , protein kinase C (PKC), and receptor-type protein tyrosine kinase. The understanding of redox signaling is crucial to pave the way for novel diagnostic tools and treatments of male infertility.
Humans ; Male ; Spermatozoa/physiology* ; Signal Transduction/physiology* ; Oxidation-Reduction ; Peroxiredoxins/physiology* ; Reactive Oxygen Species/metabolism* ; Oxidative Stress/physiology* ; Sperm Capacitation/physiology* ; Infertility, Male/metabolism*

Alzheimer's disease (AD) pathogenesis is characterized by senile plaques in the brain and evidence of oxidative damage. Oxidative stress may precede plaque formation in AD; however, the link between oxidative damage and plaque formation remains unknown. Presenilins are transmembrane proteins in which mutations lead to accelerated plaque formation and early-onset familial Alzheimer's disease. Presenilins physically interact with two antioxidant enzymes thiol-specific antioxidant (TSA) and proliferation-associated gene (PAG) of the peroxiredoxin family. The functional consequences of these interactions are unclear. In the current study we expressed a presenilin transgene in Drosophila wing and sensory organ precursors of the fly. This caused phenotypes typical of Notch signaling loss-of-function mutations. We found that while expression of TSA or PAG alone produced no phenotype, co-expression of TSA and PAG with presenilin led to an enhanced Notch loss-of-function phenotype. This phenotype was more severe and more penetrant than that caused by the expression of Psn alone. In order to determine whether these phenotypes were indeed affecting Notch signaling, this experiment was performed in a genetic background carrying an activated Notch (Abruptex) allele. The phenotypes were almost completely rescued by this activated Notch allele. These results link peroxiredoxins with the in vivo function of Presenilin, which ultimately connects two key pathogenetic mechanisms in AD, namely, antioxidant activity and plaque formation, and raises the possibility of a role for peroxiredoxin family members in Alzheimer's pathogenesis.
Amino Acid Sequence ; Animals ; Drosophila ; metabolism ; physiology ; Drosophila Proteins ; metabolism ; Molecular Sequence Data ; Peroxiredoxins ; chemistry ; genetics ; metabolism ; Presenilins ; chemistry ; metabolism ; Receptors, Notch ; metabolism ; Sequence Alignment ; Signal Transduction

BACKGROUND AND OBJECTIVEDJ-1, a suppressor of PTEN, promotes metastasis of different tumors, but its function and mechanisms in glioma metastasis remain unclear. This study aimed to investigate the effect of the DJ-1 protein on the migration and invasion of human glioma cells, and to explore potential mechanisms.

METHODSThe eukaryotic expression vector pEGFP/DJ-1 and small interfering RNA (siRNA) were constructed and transfected into human glioma SWO-38 cells. The expression of DJ-1 and PTEN in SWO-38 cells were detected by Western blot. Cell migration and invasion were detected by transwell assay.

RESULTSAfter transfection of pEGFP/DJ-1, the expression of DJ-1 (1.28 ± 0.15 vs. 0.89 ± 0.04, P < 0.05) and focal adhesion kinase (FAK) phosphorylation (0.76 ± 0.12 vs. 0.51 ± 0.04, P < 0.05) were increased, whereas the expression of PTEN (0.74 ± 0.2 vs. 1.04 ± 0.14, P < 0.05) was suppressed. After transfection of DJ-1 siRNA, both DJ-1 (0.33 ± 0.04 vs. 0.88 ± 0.06, P < 0.05) and p-FAK levels (0.33 ± 0.01 vs. 0.44 ± 0.05, P < 0.05) were decreased, but PTEN expression (1.1 ± 0.06 vs. 0.81 ± 0.12, P < 0.05) was increased. Transwell assay data showed that pEGFP/DJ-1 transfection promoted SWO-38 cell migration (57.2 ± 6.50 vs. 40.4 ± 5.0, P < 0.05) and invasion (54.6 ± 4.9 vs. 27 ± 6.7, P < 0.05), whereas DJ-1 siRNA transfection inhibited SWO-38 cells migration (54.4 ± 6.9 vs. 73.4 ± 7.6, < 0.05) and invasion (44.6 ± 5.8 vs. 69.2 ± 9.2, P < 0.05).

CONCLUSIONOver-expression of DJ-1 promotes SWO-38 cell migration and invasion possibly through the DJ-1 and the PTEN/FAK pathway.

Cell Line, Tumor ; Cell Movement ; Down-Regulation ; Focal Adhesion Protein-Tyrosine Kinases ; metabolism ; Genetic Vectors ; Glioma ; metabolism ; pathology ; Humans ; Neoplasm Invasiveness ; Oncogene Proteins ; genetics ; metabolism ; physiology ; PTEN Phosphohydrolase ; genetics ; metabolism ; Peroxiredoxins ; Phosphorylation ; Plasmids ; Protein Deglycase DJ-1 ; RNA, Small Interfering ; Signal Transduction ; Transfection

BACKGROUND/AIMS: Peroxiredoxin (Prx) belongs to a ubiquitous family of antioxidant enzymes that regulates many cellular processes through intracellular oxidative signal transduction pathways. Silica-induced lung damage involves reactive oxygen species (ROS) that trigger subsequent toxic effects and inflammatory responses in alveolar epithelial cells resulting in fibrosis. Therefore, we investigated the role of Prx in the development of lung oxidant injury caused by silicosis, and determined the implication of ROS in that process. METHODS: Lung epithelial cell lines A549 and WI26 were treated with 1% silica for 0, 24, or 48 hours, following pretreatment of the A549 cells with N-acetyl-L-cysteine and diphenylene iodonium and no pretreatment of the WI26 cells. We transfected an HA-ubiquitin construct into the A549 cell line and then analyzed the cells via Western blotting and co-immunoprecipitation. RESULTS: Silica treatment induced cell death in the A549 lung epithelial cell line and selectively degraded Prx I without impairing protein synthesis in the A549 cells, even when the ROS effect was blocked chemically by N-acetyl-L-cysteine. A co-immunoprecipitation study revealed that Prx I did not undergo ubiquitination. CONCLUSIONS: Silica treatment induces a decrease of Prx I expression in lung epithelial cell lines regardless of the presence of ROS. The silica-induced degradation of Prx does not involve the ubiquitin-proteasomal pathway.
Cell Line ; Epithelial Cells/drug effects/metabolism ; Humans ; Lung/chemistry/*drug effects/metabolism ; Peroxiredoxins/analysis/*physiology ; Protein Isoforms ; Reactive Oxygen Species/metabolism ; Silicon Dioxide/*toxicity ; Ubiquitin/metabolism

BACKGROUNDBeta(2)-adrenoceptor (beta(2)AR) desensitization is a common problem in clinical practice. beta(2)AR desensitization proceeds by at least such three mechanisms as heterologous desensitization, homologous desensitization and a kind of agonist-induced rapid phosphorylation by a variety of serine/threonine kinases. It is not clear whether there are other mechanisms. This study aimed to investigate potential mechanisms of beta(2)AR desensitization.

METHODSTwenty-four BALB/c (6-8 weeks old) mice were divided into three groups, which is, group A, phosphate buffered saline (PBS)-treated; group B, ovalbumin (OVA)-induced; and group C, salbutamol-treated. Inflammatory cell counts, cytokine concentrations of bronchoalveolar lavage fluid (BALF), pathological sections, total serum IgE, airway responsiveness, membrane receptor numbers and total amount of beta(2)AR were observed. Asthmatic mouse model and beta(2)AR desensitization asthmatic mouse model were established. Groups B and C were selected for two-dimensional gel electrophoresis (2DE) analysis so as to find key protein spots related to beta(2)AR desensitization.

RESULTSAsthmatic mouse model and beta(2)AR desensitization asthmatic mouse model were verified by inflammatory cell count, cytokine concentration of BALF, serum IgE level, airway hyperreactivity measurement, radioligand receptor binding assay, Western blot analysis, and pathologic examination. Then the two groups (groups B and C) were subjected to 2DE. Two key protein spots associated with beta(2)AR desensitization, Rho GDP-dissociation inhibitor 2 (RhoGDI(2)) and peroxiredoxin 5, were found by comparative proteomics (2DE and mass spectrum analysis).

CONCLUSIONOxidative stress and small G protein regulators may play an important role in the process of beta(2)AR desensitization.

Albuterol ; therapeutic use ; Animals ; Asthma ; drug therapy ; metabolism ; Disease Models, Animal ; Electrophoresis, Gel, Two-Dimensional ; Female ; Guanine Nucleotide Dissociation Inhibitors ; analysis ; Lung ; chemistry ; pathology ; Mice ; Mice, Inbred BALB C ; Oxidative Stress ; Peroxiredoxins ; analysis ; Proteomics ; Receptors, Adrenergic, beta-2 ; physiology ; rho-Specific Guanine Nucleotide Dissociation Inhibitors