Expression of mitochondrial thioredoxin-dependent antioxidant protein, SP-22, in normal human and inflammatory mouse placentae

DJ-1 mutation decreases astroglial release of inflammatory mediators

Mutations in DJ-1, reactive gliosis and concomitant inflammatory processes are implicated in the pathogenesis and progression of Parkinson's disease (PD). To study the physiological consequences of DJ-1 mutation in the context of neuroinflammatory insult, primary cortical astrocytes were isolated from DJ-1 knockout mice. Astrocytes were exposed to 1μg/mL lipopolysaccharide (LPS) for 24h following 2h pre-exposure to inhibitors of MEK (U0126), JNK (JNK inhibitor II) or p38 (SB203580). Real-time PCR was used to assess the LPS-induced expression of pro-inflammatory mediators cyclooxygenase 2 (COX2), inducible nitric oxide synthetase (NOS2), and tumor necrosis factor α (TNFα). LPS-induced expression of COX2 decreased similarly in DJ-1(+/+) and DJ-1(-/-) astrocytes in response to inhibition of p38, but was unaffected by inhibition of MEK or JNK. No significant alterations in NOS2 expression were observed in any inhibitor-treated cells. The inhibitors did not affect expression of TNFα; however, DJ-1(-/-) astrocytes had consistently lower expression compared to DJ-1(+/+) counterparts. Secretion of TNFα and prostaglandin E2 (PGE2) into the culture medium was significantly decreased in DJ-1(-/-) astrocytes, and inhibition of p38 decreased this secretion in both genotypes. In conclusion, DJ-1(-/-) astrocytes may provide decreased neuroprotection to surrounding neurons due to alterations in pro-inflammatory mediator expression.

Preoxiredoxin family members (Prx3 and Prx4) and pregnancy disorder (recurrent pregnancy loss)

Placenta is a pregnancy unique tissue, and proper formation of placenta is a key phenomenal step for success of a pregnancy. Peroxiredoxins (Prxs) are a family of antioxidant proteins. This family is composed of six members, among which Peroxiredoxin 3 (Prx3) and Peroxiredoxin 4 (Prx4) are expressed by cytotrophoblast cells and play an important role in the implantation and a normal placentation through their antioxidant activities. Although the presence of autoantibody against several peroxiredoxin family members was reported before, there was no report regarding the presence of antibodies against Prx3 or Prx4 in human pregnancy miscarriage. So for the first time we hypothesize and indicate that uncontrolled oxidative stress, due to anti-peroxiredoxins antibodies, may affect the proper formation of the placenta and lead to placentation-related pregnancy disorders such as miscarriage. Our results indicate that two placental proteins, Prx3 and Prx4, may act as new placental immune targets. Considering the role of antioxidant defense in the protection of placenta from oxidative stress, production of antibodies against peroxiredoxins 3 and 4 may introduce a new autoimmune hypothesis for miscarriages, which is needed to be tested in the future works.

The expression of thioredoxin-1 in preterm delivery placenta

Preterm delivery (PTD) is the leading cause of infant mortality and morbidity. However, the mechanism at the molecular level is still unknown. Placental inflammatory response and oxidative stress are associated with PTD. Thioredoxin-1 (TRX-1) regulates oxidative stress, inflammation, and the activities of transcription factors.

OBJECTIVES

The objective was to detect in placental tissues the expressions of TRX-1 and the TRX-1-related molecules: tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), thioredoxin-1-binding protein-2 (TBP-2), hypoxia inducible transcription factor 1α (HIF-1α), and forkhead box protein O3A (FoxO3A).

METHODS

PTD was defined as gestation of <37 weeks and term delivery (TD) as ≥37 weeks. The expressions of TRX-1 and TRX-1-related molecules were examined in placental tissues by real-time polymerase chain rection and western blot.

RESULTS

The expressions of TRX-1, TNF-α, COX-2, HIF-1α, and FoxO3A in the placenta of PTD were significantly higher as compared with TD, but no difference was observed in TBP-2 expression.

DISCUSSION

These results indicate that TRX-1 may be adaptively induced by the effects of inflammation and oxidative stress, suggesting protective roles for TRX-1 against these effects in the placenta of PTD.

Presence of autoantibody against two placental proteins, peroxiredoxin 3 and peroxiredoxin 4, in sera of recurrent pregnancy loss patients

PROBLEM

Recurrent pregnancy loss (RPL) is defined as two or more consecutive abortion before the 20th week of gestation. Autoimmune diseases increase the risk and accounts for at least 20% of RPL. Placenta is a pregnancy unique tissue, and proper formation of placenta is key phenomenal for success of a pregnancy. The aim of this study was to investigate the placental proteins that may act as antibody targets in RPL patients.

METHOD OF STUDY

Total placental proteins were extracted and separated using 2D-PAGE technique. Separated protein spots were transferred on PVDF membrane and blotted with sera from 20 RPL patients and compared with the protein spots that membrane blotted with sera from 20 normal women. Differentially blotted spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry mass spectrometry technique. The results of the mass analysis also were confirmed by western blot using mAb and reverse transcriptase polymerase chain reaction technique.

RESULTS

The results indicated that RPL women may produce antibody against Peroxiredoxin 3 (Prx3) and Peroxiredoxin 4 (Prx4).

CONCLUSION

Our results indicate that two placental proteins, Prx3 and Prx4, may act as new placental immune targets. Considering the role of antioxidant defense in the protection of placenta from oxidative stress, production of antibodies against peroxiredoxins 3 and 4 may introduce a new autoimmune hypothesis in RPL, which is needed to be tested in the future works.

Quantitative proteomic analysis of pregnancy-related proteins from peripheral blood mononuclear cells during pregnancy in pigs

Information obtained from peripheral blood could help us understand the underlying mechanisms in autoimmune diseases, cancer, pregnancy, and other conditions. In this paper, we present the protein map of porcine peripheral blood mononuclear cells (PBMC) to better understand the molecular expression changes that occur during pregnancy using proteomic analysis. We detected 94 differentially expressed proteins in pregnant vs. non-pregnant (NP) pigs, and a representative set of the proteins was subjected to LC-MS/MS analysis. Furthermore, the identified proteins were categorized according to their biological process and molecular function. By classifying the proteins according to their functions, a large number of differentially regulated proteins involved in anti-oxidant, detoxification and stress response pathways were found, including peroxiredoxin (PRX) 1, 2, and 6, glutathione-S-transferase (GST), annexin A2, and A6, and heat shock protein 27 (HSP 27) during pregnancy (pregnancy d of E40, embryonic day 40; E70, embryonic day 70; and E93, embryonic day 93) compared with non-pregnancy. In this study, a proteomic approach utilizing 2-DE and LC-MS/MS was applied to evaluate specific molecular expression changes during pregnancy compared with non-pregnancy. Together, these data offer new information about the proteome map and factors that are differentially regulated during maintenance of normal pregnancy.

Role of peroxiredoxin III in the pathogenesis of pre-eclampsia as evidenced in mice

As a member of peroxiredoxin (Prx) family, PrxIII has been demonstrated to play an important role in scavenging intracellular reactive oxygen species (ROS). Since PrxIII knockout mice exhibited oxidative stress in placentas resembling pathophysiologic changes in placentas of human pre-eclampsia, we measured blood pressure through the carotid artery and detected oxidative status by western blotting in pregnant mice. We did not notice hypertension in pregnant PrxIII knockout mice as compared with wild-type littermates, although endothelin-1 was overexpressed in PrxIII-deficient placentas. Our results indicate that PrxIII is not involved in pre-eclamptic development. Instead, PrxIII is an indispensable antioxidant in placentas where oxidative stress exists.

Analysis of targeted mutation in DJ-1 on cellular function in primary astrocytes

DJ-1 mutation induces early-onset Parkinson's disease, and conversely over-expression of DJ-1 is associated with cancer in numerous tissues. A gene-trap screening library conducted in embryonic stem cells was utilized for generation of a DJ-1 mutant mouse. Real-time PCR and immunoblotting were utilized to confirm functional mutation of the DJ-1 gene. Normal DJ-1 protein expression in adult mouse tissue was characterized and demonstrates high expression in brain tissue with wide systemic distribution. Primary astrocytes isolated from DJ-1(-/-) mice reveal a decreased nuclear localization of DJ-1 protein in response to rotenone or LPS, with a concomitant increase in mitochondrial localization of DJ-1 found only in the rotenone exposure. Resting mitochondrial membrane potential was significantly lower in DJ-1(-/-) astrocytes, as compared to controls. Our DJ-1 knockout mouse provides an exciting tool for exploring the molecular and physiological roles of DJ-1 to further explicate its functions in neurodegeneration.

Crucial role of peroxiredoxin III in placental antioxidant defense of mice

We observed frequent stillbirth in peroxiredoxin III (PrxIII) knockout maternal mice. Quantitative real time PCR (qRT-PCR) and Western-blot analysis revealed increased oxidative stress in placentas that were deficient in PrxIII. We did not find significant difference between PrxIII knockout maternal mice and wild-type littermates in hematological parameters, fetal number, and embryonic development. Nevertheless, we noticed enhanced expression of PrxI in erythrocytes of pregnant knockout mice. Our results provided in vivo evidence that PrxIII played a crucial role in placental antioxidant defense. Up-regulation of PrxI might provide a compensation that protected erythrocytes against oxidative damage.

Increased susceptibility of MER5 (peroxiredoxin III) knockout mice to LPS-induced oxidative stress

MER5 (also called peroxiredoxin III, PrxIII) is a member of peroxiredoxin family that has antioxidant activity. The present study was performed to investigate its in vivo function using MER5 knockout mice. MER5 knockout mice were born in normal frequency and could grow to maturity, but we found that intracellular ROS levels are significantly higher in the macrophages of the knockout mice. We examined roles of MER5 function for the oxidative stress responses by intratracheal inoculation of lipopolysaccharide (LPS) to the mice. Lung inflammation such as inflammatory cell infiltration and airway wall thickening was more severely detected in the knockout mice. At the same time, oxidative damage on DNA and proteins was more strongly detected in lung tissues of the knockout mice, including 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation and protein carbonylation. The degrees of lung inflammation and oxidative damage were positively related with LPS doses. Our results indicate that MER5 knockout mice accumulated higher intracellular ROS levels, which cause LPS-induced lung injury more severely, and thus, suggested that MER5 acts as an important scavenger of reactive oxygen species (ROS) under oxidative stress.

Enhancement of mitochondrial oxidative stress and up-regulation of antioxidant protein peroxiredoxin III/SP-22 in the mitochondria of human pre-eclamptic placentae

A growing body of evidence indicates that the pathogenesis of pre-eclampsia is closely associated with oxidative stress occurring in mitochondria. In the present study, we evaluated the degree of mitochondrial lipid peroxidation by assessing the accumulation of 4-hydroxy-2-nonenal (HNE)-modified proteins and examined the expression of mitochondrial antioxidant protein peroxiredoxin III/SP-22 in normal and pre-eclamptic human placentae. The accumulation of HNE-modified proteins increased to a greater extent in both the mitochondria and cytosol of pre-eclamptic placentae than in those of normal placentae. Moreover, the accumulation of HNE-modified proteins was much more evident in the mitochondria than in the cytosol, indicating that lipid peroxidation occurred mainly in the mitochondria of pre-eclamptic placentae. The mRNA expression of peroxiredoxin III/SP-22 was increased about 2-fold in pre-eclamptic placentae compared to normal placentae. The protein levels of peroxiredoxin III/SP-22 were approximately 4-fold higher in pre-eclamptic placentae than in normal placentae. Immunohistochemistry of placental tissues showed that the levels of peroxiredoxin III/SP-22 protein were increased in the trophoblasts of floating villi, stromal cells of stem villi, and decidual cells in pre-eclamptic placentae. These results indicate that peroxiredoxin III/SP-22 plays a crucial role in the protection of placental function from oxidative stress occurring in mitochondria of pre-eclamptic placentae.