Role of UCH-L1/ubiquitin in acute testicular ischemia–reperfusion injury

Targeting the p53 signaling pathway in cancers: Molecular mechanisms and clinical studies

Tumor suppressor p53 can transcriptionally activate downstream genes in response to stress, and then regulate the cell cycle, DNA repair, metabolism, angiogenesis, apoptosis, and other biological responses. p53 has seven functional domains and 12 splice isoforms, and different domains and subtypes play different roles. The activation and inactivation of p53 are finely regulated and are associated with phosphorylation/acetylation modification and ubiquitination modification, respectively. Abnormal activation of p53 is closely related to the occurrence and development of cancer. While targeted therapy of the p53 signaling pathway is still in its early stages and only a few drugs or treatments have entered clinical trials, the development of new drugs and ongoing clinical trials are expected to lead to the widespread use of p53 signaling-targeted therapy in cancer treatment in the future. TRIAP1 is a novel p53 downstream inhibitor of apoptosis. TRIAP1 is the homolog of yeast mitochondrial intermembrane protein MDM35, which can play a tumor-promoting role by blocking the mitochondria-dependent apoptosis pathway. This work provides a systematic overview of recent basic research and clinical progress in the p53 signaling pathway and proposes that TRIAP1 is an important therapeutic target downstream of p53 signaling.

Identification of proteins differentially expressed by glutamate treatment in cerebral cortex of neonatal rats

Glutamate leads to neuronal cell damage by generating neurotoxicity during brain development. The objective of this study is to identify proteins that differently expressed by glutamate treatment in neonatal cerebral cortex. Sprague-Dawley rat pups (post-natal day 7) were intraperitoneally injected with vehicle or glutamate (10 mg/kg). Brain tissues were isolated 4 h after drug treatment and fixed for morphological study. Moreover, cerebral cortices were collected for protein study. Two-dimensional gel electrophoresis and mass spectrometry were carried out to identify specific proteins. We observed severe histopathological changes in glutamate-exposed cerebral cortex. We identified various proteins that differentially expressed by glutamate exposure. Identified proteins were thioredoxin, peroxiredoxin 5, ubiquitin carboxy-terminal hydrolase L1, proteasome subunit alpha proteins, isocitrate dehydrogenase, and heat shock protein 60. Heat shock protein 60 was increased in glutamate exposed condition. However, other proteins were decreased in glutamate-treated animals. These proteins are related to anti-oxidant, protein degradation, metabolism, signal transduction, and anti-apoptotic function. Thus, our findings can suggest that glutamate leads to neonatal cerebral cortex damage by regulation of specific proteins that mediated with various functions.

Proteomic identification of proteins differentially expressed in response to resveratrol treatment in middle cerebral artery occlusion stroke model

Resveratrol has a neuroprotective effect against cerebral ischemia. The objective of this study was to identify proteins that are differentially expressed in the cerebral cortex of vehicle- and resveratrol-treated animals during ischemic injury. Focal cerebral ischemia was induced as middle cerebral artery occlusion (MCAO) in male rats. Rats were treated with vehicle or resveratrol before MCAO, and cerebral cortex was collected 24 hr after MCAO. Cerebral cortex proteins were identified by two-dimensional gel electrophoresis and mass spectrometry. Several proteins were identified as differentially expressed between vehicle- and resveratrol-treated animals. Among these proteins, expression of peroxiredoxin-5, isocitrate dehydrogenase [NAD⁺], apolipoprotein A-I and ubiquitin carboxy terminal hydrolase L1 was decreased in the vehicle-treated group, whereas resveratrol attenuated the injury-induced decrease in expression of these proteins. However, expression of collapsing response mediator protein 2 was increased in the vehicle-treated group, whereas resveratrol prevented the injury-induced increase in the expression of this protein. These findings suggest that resveratrol modulates the expression of various proteins that associated with oxidative stress and energy metabolism in focal cerebral ischemia.

Proteomic analysis of testicular ischemia-reperfusion injury in rats

Testicular torsion is a urological emergency that leads to serious testicular damage and male infertility. We performed this study to identify specific proteins that are differentially expressed in response to testicular torsion and detorsion-induced ischemia-reperfusion (I-R) injury. Adult male rats were divided into two groups: a sham-operated group and a testicular I-R group. Testicular torsion was induced by rotating the left testis 720° in a clockwise direction for 1 hr, and then, detorsion was performed for 24 hr. After this testicular tissues were collected, protein analysis was performed using two-dimensional gel electrophoresis and Western blot analyses. Testicular I-R injury resulted in serious histopathologic damage to the germinal cells in the seminiferous tubules and increased the number of TUNEL-positive cells in testicular tissue. Specific protein spots with a greater than 2.5-fold change in intensity between the sham-operated and testicular I-R groups were identified by mass spectrometry. Among these proteins, levels of peroxiredoxin 6, thioredoxin, heterogeneous nuclear ribonucleoproteins, ubiquitin carboxyl terminal hydrolase isozyme L5 and zinc finger AN1-type domain 3 were decreased in the testicular I-R group compared to the sham-operated group. Moreover, Western blot analysis clearly showed the decrease of these proteins in the testicular I-R group. These proteins have spermatogenesis and anti-oxidative functions. These findings suggest that testicular I-R results in cell death due to altered expression of several proteins with spermatogenesis and anti-oxidation functions.

Proteomic analysis of focal cerebral ischemic injury in male rats

The present study identified the proteins that are differentially expressed during ischemic brain injury. Adult male rats were performed a middle cerebral artery occlusion (MCAO) to induce cerebral ischemia, and brains were collected at 24 hr after MCAO. Protein analysis was performed on the cerebral cortex using two-dimensional gel electrophoresis. Protein spots with a greater than 3 fold change in intensity between the sham and MCAO groups were identified by mass spectrometry. Among these proteins, 60 kDa heat shock protein, dehydropyrimidinase-related protein 2, t-complex protein 1, and Rho GDP dissociation inhibitor levels were significantly increased in MCAO group compared to those of the sham group. In contrast, thioredoxin, peroxiredoxin-2, stathmin, ubiquitin carboxy-terminal hydrolase L1, guanine nucleotide-binding protein alpha, pyridoxal-5'-phosphate phosphatase, and apoplipoprotein A-I levels were significantly decreased in MCAO group. These results suggest that cerebral ischemia induces neuronal cells death by changing expression levels of several proteins.

Identification of proteins differentially expressed by melatonin treatment in cerebral ischemic injury--a proteomics approach

We previously reported that melatonin protects neuronal cells against ischemic brain damage. In this study, we identified proteins that were differentially expressed by melatonin treatment during ischemic brain injury. Rats were subjected to cerebral ischemia by middle cerebral artery occlusion (MCAO). Adult male rats were treated with melatonin (5 mg/kg) or vehicle prior to MCAO and brains were collected at 24 hr after MCAO. Proteins derived from the cerebral cortex were analyzed using two-dimensional gel electrophoresis. Protein spots with a greater than 2.5-fold change in intensity were identified by mass spectrometry. Among these proteins, gamma-enolase, stathmin, thioredoxin, peroxiredoxin-6, hippocalcin, protein phosphatase 2A, adenosylhomocysteinase, ubiquitin carboxy-terminal hydrolase L1, and NAD-specific isocitrate dehydrogenase subunit alpha were significantly decreased in the vehicle-treated group in comparison to the melatonin-treated group. The identified proteins consist of cell differentiation and stabilization proteins, as well as an antioxidant enzyme. In contrast, dehydroprimidinase-related protein 2 (DRP-2), a target of protein oxidation in neurodegeneration, was significantly increased in vehicle-treated animals, while melatonin prevented the injury-induced increase of DRP-2. Thus, the results of this study suggest that melatonin prevents cell death resulting from ischemic brain injury and that its neuroprotective effects are mediated by both the up- and down-regulation of various proteins.