DJ-1 Expression Research Articles

DJ-1 is activated in medulloblastoma and is associated with cell proliferation and differentiation.

BackgroundDJ-1 is a key regulator in human tumorigenesis, including brain malignancies. The mechanisms by which DJ-1 contributes to the pathogenesis of medulloblastoma (MB) remain unclear, and its impact on the prognosis for patients with MB has not been identified. The aim of this study was to determine whether the DJ-1 protein is associated with tumorigenesis of MBs, and whether DJ-1 is a valuable factor for predicting the prognosis of patients with MB.MethodsWe collected 66 pairs of MB and adjacent normal cerebellum samples. Expression of DJ-1, Ser 473-phosphorylated-Akt (p-Akt), PTEN, and Ki-67 (MIB-1) was detected by immunohistochemical staining, and the correlation of these immunostaining results with the clinicopathological features of patients with MB was determined.ResultsHigh DJ-1 expression (48.5%, 32/66) in tumor cells of MBs was significantly associated with the classic MB variant (P = 0.003), high proliferative activity (P = 0.002) and undifferentiated tumor (P = 0.001), whereas high p-Akt expression (56.1%, 37/66) was associated with tumor metastasis stage (P = 0.007), undifferentiated tumor (P = 0.007), and high-risk tumor (P = 0.002). High DJ-1 expression also correlated with high p-Akt expression and high MIB-1 index. However, only high levels of DJ-1(P = 0.009) and high MIB-1 index (P = 0.001) were strong independent prognostic factors associated with worse overall survival.ConclusionsAlthough the validity of the preliminary data in this study needs to be confirmed by a larger number of cases, our study indicates that DJ-1, PTEN, and p-Akt might play important roles in cell proliferation and differentiation of MBs. The evaluation of expression of DJ-1 and related proteins might be useful for predicting the prognosis of patients with MB.

S-allyl cysteine ameliorates the quality of sperm and provides protection from age-related sperm dysfunction and oxidative stress in rats.

Reactive oxygen species play a central role in the pathophysiology of the age-related decrease in male fertility. It has been reported that the total protein of DJ-1 was decreased in a proteomic analysis of seminal plasma from asthenozoospermia patients and a DJ-1 protein acts as a sensor of cellular redox homeostasis. Therefore, we evaluated the age-related changes in the ratio of the oxidized/reduced forms of the DJ-1 protein in the epididymis. In addition, the protective effects of S-allyl cysteine (SAC), a potent antioxidant, were evaluated against sperm dysfunction. Male rats aged 15–75 weeks were used to assess age-associated sperm function and oxidative stress. Sperm count increased until 25 weeks, but then decreased at 50 and 75 weeks. The rate of sperm movement at 75 weeks was decreased to approximately 60% of the rate observed at 25 weeks. Expression of DJ-1 decreased, but oxidized-DJ-1 increased with age. In addition, 4-hydroxy-2-nonenal modified proteins in the epididymis increased until 50 weeks of age. The total number and DNA synthetic potential of the sperm increased until 25 weeks, and then decreased. In rats 75 weeks of age, SAC (0.45% diet) attenuated the decrease in the number, motility, and DNA synthesis of sperm and inhibited the oxidized proteins. These results suggest that SAC ameliorates the quality of sperm subjected to age-associated oxidative stress.

DJ-1 is involved in the peritoneal metastasis of gastric cancer through activation of the Akt signaling pathway.

Peritoneal metastasis is a major cause of death in patients with advanced gastric carcinoma. DJ-1 is now considered to play an important role in the metastasis of various malignancies. However, it remains largely unclear whether DJ-1 is involved in the development of peritoneal metastasis by gastric carcinoma. In the present study, we showed that the expression of DJ-1 was significantly upregulated in gastric cancer specimens with peritoneal metastasis compared to those without peritoneal metastasis. Knockdown of DJ-1 expression significantly inhibited invasion and migration, in vitro and the in vivo peritoneal metastatic abilities of SGC7901 gastric cancer cells. Moreover, knockdown of DJ-1 also diminished the expression of matrix metallopeptidase (MMP)-2 and MMP-9. All of these effects were reversed by restoration of DJ-1 expression. Following investigation of the pathway through which DJ-1 regulates cell invasion and migration, DJ-1 was found to cause phosphorylation of Akt in SGC7901 gastric cancer cells. Inhibition of the Akt pathway in SGC7901 cells mimicked the effects of DJ-1 knockdown on cell migration, invasion, MMP-2 and MMP-9 expression, and abolished the effects of DJ-1 in promoting SGC7901 cell invasion and migration. Taken together, the present study revealed that DJ-1 plays an important role in the development of peritoneal carcinomatosis from gastric carcinoma, at least partially through activation of the Akt pathway and consequent upregulation of MMP-2 and MMP-9 expression. Thus, DJ-1 may be a potential therapeutic target for peritoneal carcinomatosis of gastric carcinoma.

Upregulated Parkin expression protects mitochondrial homeostasis in DJ-1 konckdown cells and cells overexpressing the DJ-1 L166P mutation

Rare genetic mutations in the DJ-1 and Parkin genes cause recessive Parkinsonism, however, the relationship between these two genes is not fully elucidated. Current emerging evidence suggests that these genes are involved in mitochondrial homeostasis, and that a deficiency in either of these two genes is associated with damages in mitochondrial function and morphology. In this study, we demonstrated that knockdown of DJ-1 expression or the overexpression of the DJ-1 L166P mutation results in a damaged phenotype in mitochondria and a hypersensitivity to H2O2-induced cell apoptosis. These phenotypes result from increased levels of endogenous oxidative stress. However, overexpression of wild-type Parkin rescued the phenotypes observed in the mitochondria of DJ-1 knockdown and DJ-1 L166P mutant cells. We also determined that there were differences between the two cell models. Furthermore, both H₂O₂ treatment and the DJ-1 L166P mutation weakened the interaction between DJ-1 and Parkin. Taken together, these findings suggested that DJ-1 and Parkin were linked through oxidative stress, and that overexpression of Parkin protects DJ-1 protein-deficient and DJ-1 L166P mutant-expressing cells via inhibition of oxidative stress.

Altered Expression of DJ-1 and PINK1 in Sporadic ALS and in the SOD1G93AALS Mouse Model

Mitochondrial dysfunction is an important mechanism in the pathogenesis of neurodegenerative diseases such as Parkinson disease and amyotrophic lateral sclerosis (ALS). DJ-1 and PTEN-induced putative kinase 1 (PINK1) are important proteins for the maintenance of mitochondrial function and protection against cell death. Mutations in the genes coding for these proteins cause familial forms of Parkinson disease. Recent studies have postulated that changes in the expression of both proteins are also involved in pathologic mechanisms in ALS mouse models. Here, we studied the mRNA and protein expression of PINK1 and DJ-1 in postmortem brain and spinal cord tissue and muscle biopsy samples from ALS patients and controls and in brain, spinal cord, and gastrocnemius muscle of SOD1(G93A) ALS mice at different disease stages. We found significant decreases of PINK1 and DJ-1 mRNA levels in muscle tissue of SOD1(G93A) mice. Together with the significant decrease of PINK1 mRNA levels in human ALS muscle tissue, statistically nonsignificant reduction of DJ-1 mRNA levels, and reduced immunostaining for PINK1 in human ALS muscle, the results suggest potential pathophysiologic roles for these proteins in both mutant SOD1 transgenic mice and in sporadic ALS(G93A).

MicroRNA-494 reduces DJ-1 expression and exacerbates neurodegeneration

Oxidative stress is believed to be a significant cause of Parkinson's disease (PD). DJ-1 is thought to be an oxidative sensor that protects cells from oxidative insult. It was reported that the level of total DJ-1 protein was significantly reduced in the substantia nigra of sporadic PD patients, suggesting that abnormal DJ-1 expression might contribute to PD pathogenesis. However, the molecular mechanisms underlying the regulation of DJ-1 expression are still not fully explored. As a post-transcriptional regulation of target gene expression, the roles of microRNAs in development and disease progression have received widespread concerns. Therefore, we hypothesized that microRNAs might participate in the regulation of the DJ-1 expression. In the present study, we found that miR-494 could bind to the 3′UTR of DJ-1. Overexpression of miR-494 significantly decreased the level of DJ-1 in vitro and rendered cells more susceptible to oxidative stress. In a MPTP mouse model, overexpression of miR-494 negatively regulated DJ-1 levels and exacerbated MPTP-induced neurodegeneration, as illustrated by the loss of dopaminergic neurons. In conclusion, upregulation of miR-494 contributed to oxidative stress induced neuronal death by inhibiting expression of DJ-1.

Neuroprotective Effects of Protocatechuic Aldehyde against Neurotoxin-Induced Cellular and Animal Models of Parkinson’s Disease

Protocatechuic aldehyde (PAL) has been reported to bind to DJ-1, a key protein involved in Parkinson’s disease (PD), and exerts potential neuroprotective effects via DJ-1 in SH-SY5Y cells. In this study, we investigated the neuroprotective pharmacological effects of PAL against neurotoxin-induced cell and animal models of PD. In cellular models of PD, PAL markedly increased cell viability rates, mitochondrial oxidation-reduction activity and mitochondrial membrane potential, and reduced intracellular ROS levels to prevent neurotoxicity in PC12 cells. In animal models of PD, PAL reduced the apomorphine injection, caused turning in 6-OHDA treated rats, and increased the motor coordination and stride decreases in MPTP treated mice. Meanwhile, in an MPTP mouse model, PAL prevented a decrease of the contents of dopamine (DA) and its metabolites in the striatum and TH-positive dopaminergic neuron loss in the substantia nigra (SN). In addition, PAL increased the protein expression of DJ-1 and reduced the level of α-synuclein in the SN of MPTP lesioned mice. PAL also increased the spine density in hippocampal CA1 neurons. The current study demonstrates that PAL can efficiently protect dopaminergic neurons against neurotoxin injury in vitro and in vivo, and that the potential mechanisms may be related to its effects in increasing DJ-1, decreasing α-synuclein and its growth-promoting effect on spine density.

Nuclear Nrf2 expression is related to a poor survival in pancreatic adenocarcinoma

The aim of this study was to investigate the expression of Nrf2, sulfiredoxin and DJ1 in pancreatic cancer.The expression of Nrf2, sulfiredoxin and DJ1 was studied immunohistochemically in a large set of pancreatic adenocarcinomas consisting of 103 cases.Eighty six percent of the cases showed cytoplasmic Nrf2 and 24% nuclear Nrf2 positivity. Sulfiredoxin positivity was observed in 54% and DJ1 positivity in all cases. Nuclear Nrf2 positivity had an association with sulfiredoxin (p=0.019) and was associated with a poor survival (p=0.010). Stage IV tumors tended to have a more nuclear Nrf2 expression (p=0.080). DJ1 expression was more often found in well-differentiated tumors (p=0.012), and DJ1 expression was associated with better survival (p=0.020).According to the results, nuclear Nrf2 expression predicts a worse survival in pancreatic adenocarcinoma, which is in keeping with its protection of cells against oxidative or xenobiotic stress. In accordance with Nrf2's regulation of the synthesis of sulfiredoxin, there was an association between them (p=0.019). DJ1 had no association with Nrf2, and its expression predicted a better survival of patients.

DJ-1 modulates aggregation and pathogenesis in models of Huntington's disease

The oxidation-sensitive chaperone protein DJ-1 has been implicated in several human disorders including cancer and neurodegenerative diseases. During neurodegeneration associated with protein misfolding, such as that observed in Alzheimer's disease and Huntington's disease (HD), both oxidative stress and protein chaperones have been shown to modulate disease pathways. Therefore, we set out to investigate whether DJ-1 plays a role in HD. We found that DJ-1 expression and its oxidation state are abnormally increased in the human HD brain, as well as in mouse and cell models of HD. Furthermore, overexpression of DJ-1 conferred protection in vivo against neurodegeneration in yeast and Drosophila. Importantly, the DJ-1 protein directly interacted with an expanded fragment of huntingtin Exon 1 (httEx1) in test tube experiments and in cell models and accelerated polyglutamine aggregation and toxicity in an oxidation-sensitive manner. Our findings clearly establish DJ-1 as a potential therapeutic target for HD and provide the basis for further studies into the role of DJ-1 in protein misfolding diseases.

Sesamol and naringenin reverse the effect of rotenone-induced PD rat model

In the previous report (Sonia Angeline et al., 2012), we showed an altered expression of protective proteins in rotenone-induced Parkinson’s disease (PD)-like rat model. This model exhibited a marked attenuation in the expression of parkin, C terminus Hsp70 interacting protein (CHIP) and PARK 7 protein (DJ1) while enhanced levels of caspases and ubiquitin were seen. Herein, we confirmed the neuroprotective role of sesamol and naringenin individually on rotenone-induced rodent model of PD. Rotenone administration was given for 11days to generate the PD model (Sonia Angeline et al., 2012). From 11th day onward individual doses of sesamol (15mg/kg) and naringenin (10mg/kg) drugs were given orally to the rotenone PD rat model for 10 consecutive days. The impact of drugs markedly improved the motor skills, body weight, expression of parkin, DJ1, tyrosine hydroxylase and CHIP compared to the group treated with rotenone alone in the striatum and substantia nigra. These results were correlated with the reduction in caspase and ubiquitin levels by immunostaining and immunoblotting. Moreover, improved morphology and survivability of neurons were seen upon sesamol and naringenin treatment in the same rat PD model. Further we confirmed the efficacy of neuroprotective biomolecule administration on muscle from the above PD model and observed the restoration in muscle morphology, elevated level of parkin, DJ1, differential expression of heat shock proteins and reduced cell death. To conclude, for the first time we are demonstrating the comprehensive role of sesamol and naringenin (rotenone-induced PD model) in neuro and myoprotection that would have great clinical significance.

DJ-1 and androgen receptor immunohistochemical expression in prostatic carcinoma: A possible role in carcinogenesis

Background and AimAndrogen plays a fundamental role in the growth and differentiation of prostate. Androgen receptor (AR) expression may represent a potential marker of prognosis in prostate cancer. However, there have been variable results regarding its ability to predict clinical progression. Despite the oncogenic properties of DJ-1, its significance in prostate cancer development and progression is not well understood. This research shed some light on the possible role of immunohistochemical expression of DJ-1 in clinically localized prostatic carcinoma in relation to the established role of AR and other clinicopathologic parameters. Materials and MethodsThe immunohistochemical expression of AR and DJ-1 was evaluated in 129 samples including benign hyperplasia (n=60) and prostatic carcinoma (n=69). ResultsThe mean value of AR immunostaining was significantly higher in prostatic carcinomas than in benign hyperplasia (P=0.001). A significant inverse correlation was found between AR immunostaining and the grade of prostatic carcinomas. A significantly higher median DJ-1 score was found in prostatic carcinoma than in benign hyperplasia (P=0.0001). There was a significant direct correlation between AR and DJ-1 score (P=0.0001). AR is more sensitive in predicting prostatic carcinoma than DJ-1 but DJ-1 is more specific than AR. ConclusionAR nuclear expression was consistently present in benign and adenocarcinoma epithelium. But, there may be limited clinical use for AR expression in localized carcinoma due to its constant heterogeneity. DJ-1 with its oncogenic properties, specificity for prostatic carcinoma and homogenous expression gives an ideal complementary role to AR in the detection and treatment of prostatic carcinomas.

Abstract 75: Nrf2 Mediates the Antioxidant Effect of D2r Via Dj-1 in the Kidney

Renal dopamine D2 receptor (D2R) dysfunction is associated with increased oxidative stress and high blood pressure. We have reported that DJ-1 is regulated by D2R in the kidney. Nrf2 is a transcription factor that regulates the expression of several antioxidant genes. We hypothesize that Nrf2 is involved in the DJ-1-mediated regulation of reactive oxygen species (ROS) production in the kidney. DJ-1 and Nrf2 co-inmunoprecipitate in mouse kidney. Selective renal silencing of D2R in mice by the renal subcapsular infusion of D2R siRNA (~50%) decreases Nrf2 expression (63.4%±3.4, n=7, P<0.05), and silencing of D2R expression in mouse proximal tubule cells (mRPTCs) decrease Nrf2 promoter activity (53±2%, n=5, P<0.05). Silencing DJ-1 expression in mRPTCs, via siRNA, decreases the expression of DJ-1 (75±4.5%, n=4, P<0.05), Nrf2 (63.2±6%, n=3, P<0.05), NQO1 (71±1%, n=3, P<0.05), and GST Yc-2 (42±1%, n=4, P<0.05) and Nrf2 promoter activity (58±1%, n=5, P<0.05). Selective renal silencing of DJ-1 in mice by renal subcapsular infusion of DJ-1 siRNA decreases expression of DJ-1 (31±2.6%, n=3, P<0.05), Nrf2 (57±7.9%,n=3, P<0.05), NQO1 (46±9.3%, n=3, P<0.05) and GST Yc2 (28±2.2%, n=3, P<0.05) and increases blood pressure (BP). DJ-1 -/- mice also have increased systolic BP (30.7±1%, P<0.01, n=5 under anesthesia) and renal expression of nitro-tyrosine (76.8±13.5%, P<0.05, n=5), and decreases the expression of Nrf2 (46.8±6.8%, n=5, P<0.05) and NQO1 (19.4±2.7%, n=5, P<0.05). Silencing Nrf2 expression mRPTCs via siRNA decreases the expression of Nrf2 (34±1.8%, n=4, P<0.05), NQO1 (29.1±0.5%, n=4, P<0.05), and increases Nox2 (137±23.7%, n=4, P<0.05), but the expression of Nox4 and DJ-1 are not affected. Quinpirole a D2R agonist, does not modify the expression of Nrf2, NQO1, GST Yc-2, and Nrf2 promoter activity in MPCTS. However, in the presence of H 2 O 2 , quinpirole increases Nrf2 promoter activity (220±58.4%, n=5, P<0.05) and an effect that is blocked by pretreatment with D2R antagonist L741,626. Therefore, the inhibitory effect of DJ-1 on renal ROS production is, in part, mediated by positive regulation of Nrf2. Moreover, D2R and DJ-1 are necessary for normal Nrf2 activity to keep a normal redox balance in the kidney.

Parkinson Disease Protein DJ-1 Binds Metals and Protects against Metal-induced Cytotoxicity

The progressive loss of motor control due to reduction of dopamine-producing neurons in the substantia nigra pars compacta and decreased striatal dopamine levels are the classically described features of Parkinson disease (PD). Neuronal damage also progresses to other regions of the brain, and additional non-motor dysfunctions are common. Accumulation of environmental toxins, such as pesticides and metals, are suggested risk factors for the development of typical late onset PD, although genetic factors seem to be substantial in early onset cases. Mutations of DJ-1 are known to cause a form of recessive early onset Parkinson disease, highlighting an important functional role for DJ-1 in early disease prevention. This study identifies human DJ-1 as a metal-binding protein able to evidently bind copper as well as toxic mercury ions in vitro. The study further characterizes the cytoprotective function of DJ-1 and PD-mutated variants of DJ-1 with respect to induced metal cytotoxicity. The results show that expression of DJ-1 enhances the cells' protective mechanisms against induced metal toxicity and that this protection is lost for DJ-1 PD mutations A104T and D149A. The study also shows that oxidation site-mutated DJ-1 C106A retains its ability to protect cells. We also show that concomitant addition of dopamine exposure sensitizes cells to metal-induced cytotoxicity. We also confirm that redox-active dopamine adducts enhance metal-catalyzed oxidation of intracellular proteins in vivo by use of live cell imaging of redox-sensitive S3roGFP. The study indicates that even a small genetic alteration can sensitize cells to metal-induced cell death, a finding that may revive the interest in exogenous factors in the etiology of PD.

DJ-1-Dependent Regulation of Oxidative Stress in the Retinal Pigment Epithelium (RPE)

BackgroundDJ-1 is found in many tissues, including the brain, where it has been extensively studied due to its association with Parkinson’s disease. DJ-1 functions as a redox-sensitive molecular chaperone and transcription regulator that robustly protects cells from oxidative stress.MethodologyRetinal pigment epithelial (RPE) cultures were treated with H2O2 for various times followed by biochemical and immunohistological analysis. Cells were transfected with adenoviruses carrying the full-length human DJ-1 cDNA and a mutant construct, which has the cysteine residues at amino acid 46, 53 and 106 mutated to serine (C to S) prior to stress experiments. DJ-1 localization, levels of expression and reactive oxygen species (ROS) generation were also analyzed in cells expressing exogenous DJ-1 under baseline and oxidative stress conditions. The presence of DJ-1 and oxidized DJ-1 was evaluated in human RPE total lysates. The distribution of DJ-1 was assessed in AMD and non-AMD cryosectionss and in isolated human Bruch’s membrane (BM)/choroid from AMD eyes.Principal FindingsDJ-1 in RPE cells under baseline conditions, displays a diffuse cytoplasmic and nuclear staining. After oxidative challenge, more DJ-1 was associated with mitochondria. Increasing concentrations of H2O2 resulted in a dose-dependent increase in DJ-1. Overexpression of DJ-1 but not the C to S mutant prior to exposure to oxidative stress led to significant decrease in the generation of ROS. DJ-1 and oxDJ-1 intensity of immunoreactivity was significantly higher in the RPE lysates from AMD eyes. More DJ-1 was localized to RPE cells from AMD donors with geographic atrophy and DJ-1 was also present in isolated human BM/choroid from AMD eyes.Conclusions/SignificanceDJ-1 regulates RPE responses to oxidative stress. Most importantly, increased DJ-1 expression prior to oxidative stress leads to decreased generation of ROS, which will be relevant for future studies of AMD since oxidative stress is a known factor affecting this disease.

Expression of DJ-1 in Endometrial Cancer

DJ-1 was originally cloned as a putative oncogene capable of transforming NIH3T3 cells in cooperation with H-Ras or c-Myc, which has been implicated in the pathogenesis of some solid tumors. The aim of this study was to investigate the expression and clinical significance of DJ-1 in endometrial cancer and study its effect on cell proliferation and apoptosis in endometrial cancer Ishikawa cells. Reverse transcription polymerase chain reaction and Western blotting were performed to determine the DJ-1 expression in 100 surgical specimens of endometrial cancer tissues, paired tumor-adjacent tissues, and 30 surgical specimens of normal endometrium tissues. The proliferation variety of endometrial cancer Ishikawa cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium assay after transfecting the interference plasmid pGPU6/GFP/neo-DJ-1-shRNA into Ishikawa cells. Real-time polymerase chain reaction and Western blotting were used to evaluate the effect of interference plasmid on target gene expression. Apoptosis rate was determined by flow cytometry. DJ-1 expression in endometrial cancer tissues was higher than in tumor-adjacent tissues and normal endometrial tissues. At the same time, it was associated with signs of cancer progression, including differentiation, myometrial invasion depth, and presence of lymph node metastasis. Knocking down DJ-1 promoted the apoptosis of Ishikawa cells. High DJ-1 expression seems to be negatively correlated with apoptosis. Meanwhile, it may be part of the mechanisms for the development, invasion, and metastasis in endometrial cancer.

Changes in expression of DJ-1 protein during myocardial ischemia-reperfusion in diabetic rats

Objective To evaluate the changes in the expression of DJ-1 protein during myocardial ischemia-reperfusion (I/R) in diabetic rats.Methods Fifty male Sprague-Dawley rats,weighing 220-280 g,were used in this study.Type 1 diabetes mellitus was induced by intraperitoneal streptozotocin 65 mg/kg and confirmed by fasting blood glucose ＞ 16.7 mmol/L.Forty animals with type 1 diabetes mellitus were randomly divided into 3 groups:diabetes group (group D,n =10),diabetic sham operation group (group DS,n =15) and diabetic I/R group (group DIR,n =15).Another 10 non-diabetic rats in which citrate buffer 6 ml/kg was injected intraperitoneally were served as control group (group C).Myocardial I/R was produced by occlusion of the anterior descending branch of left coronary artery for 30 min followed by 120 min reperfusion in group I/R.At 120 min of reperfusion,5 rats were sacrificed and myocardial specimens were c(on)tained for determination of infarct size in groups DS and DIR,and 10 rats were sacrificed and myocardial specimens were obtained for microscopic examination and for determination of cell apoptosis,malondialdehyde (MDA) content,superoxide dismutase (SOD) activity and expression of DJ-1 and phosphatase and tensin homologue (PTEN) protein.Apoptotic index (AI) was calculated.Linear correlation between the expression of DJ-1 protein and MDA content,SOD activity,AI and expression of PTEN protein was analyzed.Results Compared with group DS,the myocardial infract size was significantly increased in group DIR (P ＜ 0.05).Compared with group C,MDA content and AI were significantly increased,SOD activity was decreased,the expression of DJ-1 was down-regulated,and the expression of PTEN protein was up-regulated in groups D,DS and DIR (P ＜ 0.05).Compared with groups D and DS,MDA content and AI were significantly increased,SOD activity was decreased,the expression of DJ-1 was down-regulated,and the expression of PTEN protein was up-regulated in group DIR (P ＜ 0.05).There was no significant difference in the parameters mentioned above between groups D and DS (P ＞ 0.05).There was linear correlation between the expression of DJ-1 protein and MDA content,SOD activity,AI and expression of PTEN protein and the correlation coefficients (r) were-0.734,0.593,-0.818,and-0.812 in turn.Conclusion Down-regulation of DJ-1 protein expression is involved in myocardial I/R injury in diabetic rats via decreasing anti-oxidative stress responses and upregulating PTEN protein expression. Key words: Intracellular signaling peptides and proteins; Myocardial reperfusion injury; Diabetes mellitus

Tetrandrine Attenuated Cerebral Ischemia/Reperfusion Injury and Induced Differential Proteomic Changes in a MCAO Mice Model Using 2-D DIGE

Ischemic stroke is the most common type of stroke and brings about a big disease burden because of high mortality and disability in China. Tetrandrine, a bisbenzylisoquinoline alkaloid isolated from the Chinese herb Radix Stephania tetrandra, has been demonstrated to possess anti-inflammatory and free radical scavenging effects and even regulate astrocyte activation, but the possible role of tetrandrine in ameliorating cerebral ischemia/reperfusion injury of ischemic stroke remains unknown. The aim of this study was to determine the effects of tetrandrine on neurological injury and differential proteomic changes induced by transient reversible middle cerebral artery occlusion (MCAO) in mice. Male Balb/c mice were divided into sham (n=30), MCAO+saline as control (n=30), and MCAO+Tet as tetrandrine-treated (n=30) groups. Mice in the control and tetrandrine-treated groups underwent 120min of MCAO following reperfusion. Immediately and 2h after MCAO, the mice received either normal saline (sham operated and control groups) or tetrandrine (tetrandrine-treated group) intraperitoneally. Neurological defects, brain water content, and infarct volume at 24h after stoke were used to evaluate neurological injury extent. Treatment with tetrandrine not only mitigated cerebral neurological deficits (P<0.05) and infarct size (P<0.01), but also decreased brian edema in the ischemic brain (P<0.05). Then, fluorescence two-dimensional difference in gel electrophoresis was used to detect our systematic differential profiling of proteomic changes responding to tetrandrine administration. We validated that the expression of GRP78, DJ-1 and HYOU1 was associated with neuroprotective effect of tetrandrine in MCAO model by Western blotting. These findings indicate a potential neuroprotective role of tetrandrine for ischemic stroke and yield insights into cellular and molecular mechanisms of tetrandrine taking place in ischemic stroke.

The positive correlation between DJ‐1 and β‐catenin expression shows prognostic value for patients with glioma

The relationship between DJ-1 and β-catenin, and its impact on the prognosis for glioma patients has not been fully understood. This study determined the effect of DJ-1 on β-catenin and the prognostic significance of this interaction in glioma patients. We collected tumor specimens from 88 glioma patients and determined the expression of DJ-1, β-catenin and PTEN by using immunohistochemical staining. The involvement of DJ-1 and β-catenin in glioma cell lines was evaluated by immunohistochemistry and Western blotting. High DJ-1 expression (37.5%) and high β-catenin expression (34.1%) in glioma specimens were significantly associated with high grade and poor prognosis in glioma patients. However, only high levels of DJ-1 (P = 0.014) was a strong independent prognostic factor, correlated with a reduced overall survival time. In vitro DJ-1 expression was positively correlated with the expression levels of β-catenin and p-Akt, and negatively correlated with PTEN expression in U87, U251 MG, SWO-38 and SHG44 human glioma cell lines. After the knockdown of DJ-1, Akt, p-Akt or β-catenin expression levels were not affected in the PTEN-null cell lines (U87 and U251 MG). However, in the SWO-38 cell line, which has wild-type PTEN protein, the level of PTEN increased while Akt/p-Akt and β-catenin levels were reduced. Furthermore, β-catenin staining weakened in SWO-38 cells after DJ-1 levels decreased according to immunocytochemical analysis. In conclusion, DJ-1 and β-catenin may contribute to the development and recurrence of glioma and are valuable prognostic factors for glioma patients. DJ-1 may regulate β-catenin expression via PTEN and p-Akt.

DJ-1 protein expression as a predictor of pathological complete remission after neoadjuvant chemotherapy in breast cancer patients

Parkinson's disease is associated with DJ-1/Parkinson protein 7 dysfunction. In contrast, hyperactivity of DJ-1 increases the resistance of cancer cells to apoptosis. Recent genetic studies showed that, in addition to apoptosis pathways, DJ-1 is also involved in cellular defense against reactive oxygen species. The activity of apoptotic and cellular defense pathways is key in determining drug sensitivity. DJ-1 overexpression is associated with various cancers. However, we previously found that there were approximately 50 % patients with breast cancers that expressed low levels of DJ-1 protein, despite mRNA upregulation. Furthermore, low DJ-1 expression was a significant predictor of poor clinical outcome in these patients. This study aimed to determine the association between low DJ-1 protein expression and pathological complete remission (pCR) after neoadjuvant chemotherapy in breast cancer patients. Expression of DJ-1 in pre-therapeutic needle biopsies and surgical specimens obtained from 205 breast cancer cases that received neoadjuvant chemotherapy was determined using immunohistochemistry and in situ hybridization. Chemotherapy comprised epirubicin/cyclophosphamide taxane-based regimens with or without the inclusion of trastuzumab. Univariate and multivariate analyses were used to evaluate the predictive value of DJ-1 on pCR. Low DJ-1 protein expression was detected in 45.3 % (93/205) of all breast cancer cases and in 79.6 % (39/49) of pCR cases, irrespective of maintained mRNA levels. DJ-1 expression [hazard ratio (HR): 1.36; 95 % confidence interval (CI): 1.01-1.84] and HER2 status (HR: 0.84; 95 % CI: 0.62-1.14), in contrast to histological grade, hormone receptors status, Ki-67 labeling index, and intrinsic subtype, were significant predictors of pCR. Low DJ-1 expression predicted pCR in luminal A (P = 0.0004), luminal B (P = 0.0194), and triple negative (P = 0.0143) subtypes breast cancer patients and in patients receiving additional trastuzumab treatment (P = 0.008). In conclusion, low DJ-1 protein expression is a significant predictor of pCR after neoadjuvant chemotherapy in breast cancer patients.

Puerarin attenuates neuronal degeneration and blocks oxidative stress to elicit a neuroprotective effect on substantia nigra injury in 6-OHDA-lesioned rats

In the present study, we aimed to investigate the protective effect of puerarin (PR) on the substantia nigra (SN) of 6-hydroxydopamine (6-OHDA)-lesioned rats. Our results show that glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities were increased, while the malonaldehyde (MDA) content was reduced in the SN following PR treatment. Furthermore, examination of specific immunostaining revealed that histopathological lesions in SN tissue were alleviated. Similarly, the mRNA level of heme oxygenase-1 (HO-1) was notably decreased, and the expression of NAD(P)H: quinone oxidoreductase-1 (NQO-1) mRNA was increased. As revealed by Western blot analysis, PR therapy contributed to a marked expression of DJ-1 and superoxide dismutase-2 (SOD2) at the protein levels in the SN of 6-OHDA-lesioned rats. Taken together, these findings suggest that puerarin effectively exerts its neuroprotective action against 6-OHDA-induced Parkinsonian rats through the enhancement of antioxidant capability and attenuation of oxidative stress injury, thereby inhibiting neurodegeneration in SN tissue.