Microglial peroxiredoxin V acts as an inducible anti-inflammatory antioxidant through cooperation with redox signaling cascades

Ablation of Shank1 Protects against 6-OHDA-induced Cytotoxicity via PRDX3-mediated Inhibition of ER Stress in SN4741 Cells

BACKGROUND

Postsynaptic density (PSD) is an electron-dense structure that contains various scaffolding and signaling proteins. Shank1 is a master regulator of the synaptic scaffold located at glutamatergic synapses, and has been proposed to be involved in multiple neurological disorders.

METHODS

In this study, we investigated the role of shank1 in an in vitro Parkinson's disease (PD) model mimicked by 6-OHDA treatment in neuronal SN4741 cells. The expression of related molecules was detected by western blot and immunostaining.

RESULTS

We found that 6-OHDA significantly increased the mRNA and protein levels of shank1 in SN4741 cells, but the subcellular distribution was not altered. Knockdown of shank1 via small interfering RNA (siRNA) protected against 6-OHDA treatment, as evidenced by reduced lactate dehydrogenase (LDH) release and decreased apoptosis. The results of RT-PCR and western blot showed that knockdown of shank1 markedly inhibited the activation of endoplasmic reticulum (ER) stress associated factors after 6-OHDA exposure. In addition, the downregulation of shank1 obviously increased the expression of PRDX3, which was accompanied by the preservation of mitochondrial function. Mechanically, downregulation of PRDX3 via siRNA partially prevented the shank1 knockdowninduced protection against 6-OHDA in SN4741 cells.

CONCLUSION

In summary, the present study has provided the first evidence that the knockdown of shank1 protects against 6-OHDA-induced ER stress and mitochondrial dysfunction through activating the PRDX3 pathway.

Peroxiredoxin 5 protects HepG2 cells from ethyl β-carboline-3-carboxylate-induced cell death via ROS-dependent MAPK signalling pathways

Peroxiredoxin 5 (PRDX5) is the member of Prxs family, widely reported to be involved in various types of cell death. We previously found that PRDX5 knockdown increases the susceptibility of cell death upon oxidative stress treatment. Ethyl β-carboline-3-carboxylate (β-CCE), an alkaloid extracted from Picrasma quassioides, has been reported to play a role in neuronal disease, but its anti-cancer potential on liver cancers remains unknown. Here, we studied the effect of PRDX5 on ethyl β-carboline-3-carboxylate (β-CCE)-induced apoptosis of hepatomas. High expression level of PRDX5 was deeply related with the postoperative survival of patients with liver cancer, indicating that PRDX5 may be a biomarker of live cancer processing. Moreover, PRDX5 over-expression in HepG2 cells significantly inhibited β-CCE-induced cell apoptosis and cellular ROS levels as well as mitochondrial dysfunction. Signalling pathway analysis showed that β-CCE could significantly up-regulate the ROS-dependent MAPK signalling, which were in turn boosts the mitochondria-dependent cell apoptosis. Moreover, PRDX5 over-expression could reverse the anti-cancer effects induced by β-CCE in HepG2 cells. Our findings suggest that PRDX5 has a protective role on β-CCE-induced liver cancer cell death and provides new insights for using its anti-cancer properties for liver cancer treatment.

The influence of preconditioning with low dose of LPS on paraquat-induced neurotoxicity, microglia activation and expression of α-synuclein and synphilin-1 in the dopaminergic system

Background

Prolonged inflammation, oxidative stress, and protein aggregation are important factors contributing to Parkinson’s disease (PD) pathology. A known ROS generator, pesticide paraquat (PQ), was indicated as an environmental substance potentially increasing the incidence of PD and is used to model this disease. We investigated if a combination of inflammation and oxidative stress in subthreshold doses would exacerbate the modelled neuropathology.

Methods

We examined the late effects of acute or repeated peripheral inflammation induced by low dose of LPS (10 μg/kg, ip) on PQ toxicity in the rat nigrostriatal dopaminergic pathway, microglial activation markers and expression of major Lewy bodies proteins, α-synuclein and synphilin-1.

Results

We observed that LPS increased, while PQ decreased body temperature and microglia CD11b expression in the SN. Single LPS pretreatment, 3 h before repeated weekly PQ injections (4×) slightly aggravated neuronal degeneration in the SN. Moreover, degeneration of dopaminergic neurons after weekly repeated inflammation itself (4×) was observed. Interestingly, repeated LPS administration combined with each PQ dose counteracted such effect. The expression of α-synuclein decreased after repeated LPS injections, while only combined, repeated LPS and PQ treatment lowered the levels of synphilin-1. Therefore, α-synuclein and synphilin-1 expression change was influenced by different mechanisms. Concomitantly, decreased levels of the two proteins correlated with decreased degeneration of dopaminergic neurons and with a normalized microglia activation marker.

Conclusions

Our results indicate that both oxidative insult triggered by PQ and inflammation caused by peripheral LPS injection can individually induce neurotoxicity. Those factors act through different mechanisms that are not additive and not selective towards dopaminergic neurons, probably implying microglia. Repeated, but small insults from oxidative stress and inflammation when administered in significant time intervals can counteract each other and even act protective as a preconditioning effect. The timing of such repetitive insults is also of essence.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43440-021-00340-1.

Peroxiredoxins as Potential Targets for Cardiovascular Disease

Increased oxidative stress (OS) is considered a common etiology in the pathogenesis of cardiovascular disease (CVD). Therefore, the precise regulation of reactive oxygen species (ROS) in cardiovascular cells is essential to maintain normal physiological functions. Numerous regulators of cellular homeostasis are reportedly influenced by ROS. Hydrogen peroxide (H₂O₂), as an endogenous ROS in aerobic cells, is a toxic substance that can induce OS. However, many studies conducted over the past two decades have provided substantial evidence that H₂O₂ acts as a diffusible intracellular signaling messenger. Antioxidant enzymes, including superoxide dismutases, catalase, glutathione peroxidases, and peroxiredoxins (Prdxs), maintain the balance of ROS levels against augmentation of ROS production during the pathogenesis of CVD. Especially, Prdxs are regulatory sensors of transduced intracellular signals. The intracellular abundance of Prdxs that specifically react with H₂O₂ act as regulatory proteins. In this review, we focus on the role of Prdxs in the regulation of ROS-induced pathological changes in the development of CVD.

PRDX5 as a novel binding partner in Nrf2-mediated NSCLC progression under oxidative stress

Non-small-cell lung cancer (NSCLC) is one of the most common malignant tumors in the world. Reactive oxidative species (ROS) and nuclear factor-related factor 2 (Nrf2) -antioxidant response element (ARE) signal pathway are known to play important roles in the development of NSCLC. In this study, we identified Peroxiredoxin 5 (PRDX5) as a novel binding partner for Nrf2. PRDX5 was significantly increased in human NSCLC specimens and cell lines. Nrf2 interacted with PRDX5 in H₂O₂-stimulated NCSLC cells, and the interaction promoted the expression of NAD(P)H: quinone oxidoreductase 1 (NQO1) protein in NSCLC cells. Further, high expression of Nrf2 and PRDX5 were associated with worsened prognosis in patients with NSCLC significantly. Moreover, animal studies showed that the growth of tumors treated with Nrf2 and PRDX5 shRNA was significantly lower than that of the other groups. All these data indicated that overexpressed PRDX5 in NSCLC promoted binding with Nrf2 and enhanced NQO1 expression and NSCLC development. Overall, our studies demonstrated that PRDX5 can be a novel binding partner of Nrf2 in promoting NCSLC development under oxidative stress and provide potential opportunity for improving NSCLC therapy.

Peroxiredoxin V Inhibits Emodin-induced Gastric Cancer Cell Apoptosis via the ROS/Bcl2 Pathway

BACKGROUND/AIM

Peroxiredoxin (Prx) protein family is aberrantly expressed in various cancers including gastric cancer. Among the six family members, Prx V has been known as an antioxidant enzyme which scavenges intracellular reactive oxygen species (ROS) and modulates cellular apoptosis. This study aimed at investigating the role of Prx V in apoptosis of gastric cancer cells.

MATERIALS AND METHODS

Stably constructed Prx V knockdown, over-expression and mock AGS cells (a human gastric adenocarcinoma cell line) were used to study the effect of Prx V on emodin-induced apoptosis by western blotting, cell viability, apoptosis and ROS detection assays.

RESULTS

Overexpression of Prx V significantly decreased emodin-induced cellular apoptosis and ROS levels compared to Mock and Prx V knockdown AGS cells. Also, overexpression of Prx V down-regulated the expression of pro-apoptotic proteins, Bad and cleaved PARP, and increased the expression of anti-apoptotic protein, Bcl2.

CONCLUSION

Prx V suppresses AGS cell apoptosis via scavenging intracellular ROS and modulating apoptosis-related markers.

Peroxiredoxin V (PrdxV) negatively regulates EGFR/Stat3-mediated fibrogenesis via a Cys48-dependent interaction between PrdxV and Stat3

Activation of the epidermal growth factor receptor (EGFR)/signal transducer and activator of transcription 3 (Stat3) signaling pathway has been reported to be associated with renal fibrosis. We have recently demonstrated that peroxiredoxin V (PrdxV) acted as an antifibrotic effector by inhibiting the activity of Stat3 in TGF-β-treated NRK49F cells. However, the underlying mechanism of PrdxV remains poorly understood. To investigate molecular mechanism of PrdxV, we used a transgenic mouse model expressing PrdxV siRNA (PrdxVsi mice) and performed unilateral ureteral obstruction (UUO) for 7 days. 209/MDCT cells were transiently transfected with HA-tagged WT PrdxV and C48S PrdxV. Transgenic PrdxVsi mice displayed an exacerbated epithelial-to-mesenchymal transition (EMT) as well as an increase in oxidative stress induced by UUO. In the UUO kidney of the PrdxVsi mouse, knockdown of PrdxV increased Tyr1068-specific EGFR and Stat3 phosphorylation, whereas overexpression of WT PrdxV in 209/MDCT cells showed the opposite results. Immunoprecipitation revealed the specific interaction between WT PrdxV and Stat3 in the absence or presence of TGF-β stimulation, whereas no PrdxV-EGFR or C48S PrdxV-Stat3 interactions were detected under any conditions. In conclusion, PrdxV is an antifibrotic effector that sustains renal physiology. Direct interaction between PrdxV and Stat3 through Cys48 is a major molecular mechanism.

Danger signals in stroke and their role on microglia activation after ischemia

Ischemic stroke is a major cause of death. Besides the direct damage resulting from oxygen and glucose deprivation, sterile inflammation plays a pivotal role in increasing cellular death. Damaged-associated molecular patterns (DAMPs) are passively released from dying cells and activate the innate immune system. Thus, they take part in the direct and rapid activation of the inflammatory response after stroke onset. In this review the role of the most important DAMPs, high mobility group box 1, heat and cold shock proteins, purines, and peroxiredoxins, are addressed. Moreover, intracellular pathways activated by DAMPs in microglia are illuminated.

Peroxiredoxin I is important for cancer-cell survival in Ras-induced hepatic tumorigenesis

Peroxiredoxin I (Prx I), an antioxidant enzyme, has multiple functions in human cancer. However, the role of Prx I in hepatic tumorigenesis has not been characterized. Here we investigated the relevance and underlying mechanism of Prx I in hepatic tumorigenesis. Prx I increased in tumors of hepatocellular carcinoma (HCC) patients that aligned with overexpression of oncogenic H-ras. Prx I also increased in H-ras^G12V transfected HCC cells and liver tumors of H-ras^G12V transgenic (Tg) mice, indicating that Prx I may be involved in Ras-induced hepatic tumorigenesis. When Prx I was knocked down or deleted in HCC-H-ras^G12V cells or H-ras^G12V Tg mice, cell colony or tumor formation was significantly reduced that was associated with downregulation of pERK pathway as well as increased intracellular reactive oxygen species (ROS) induced DNA damage and cell death. Overexpressing Prx I markedly increased Ras downstream pERK/FoxM1/Nrf2 signaling pathway and inhibited oxidative damage in HCC cells and H-ras^G12V Tg mice. In this study, we found Nrf2 was transcriptionally activated by FoxM1, and Prx I was activated by the H-ras^G12V/pERK/FoxM1/Nrf2 pathway and suppressed ROS-induced hepatic cancer-cell death along with formation of a positive feedback loop with Ras/ERK/FoxM1/Nrf2 to promote hepatic tumorigenesis.

The curious case of peroxiredoxin-5: what its absence in aves can tell us and how it can be used

Background

Peroxiredoxins are ubiquitous thiol-dependent peroxidases that represent a major antioxidant defense in both prokaryotic cells and eukaryotic organisms. Among the six vertebrate peroxiredoxin isoforms, peroxiredoxin-5 (PRDX5) appears to be a particular peroxiredoxin, displaying a different catalytic mechanism, as well as a wider substrate specificity and subcellular distribution. In addition, several evolutionary peculiarities, such as loss of subcellular targeting in certain species, have been reported for this enzyme.

Results

Western blotting analyses of 2-cys PRDXs (PRDX1–5) failed to identify the PRDX5 isoform in chicken tissue homogenates. Thereafter, via in silico analysis of PRDX5 orthologs, we went on to show that the PRDX5 gene is conserved in all branches of the amniotes clade, with the exception of aves. Further investigation of bird genomic sequences and expressed tag sequences confirmed the disappearance of the gene, though TRMT112, a gene located closely to the 5′ extremity of the PRDX5 gene, is conserved. Finally, using in ovo electroporation to overexpress the long and short forms of human PRDX5, we showed that, though the gene is lost in birds, subcellular targeting of human PRDX5 is conserved in the chick.

Conclusions

Further adding to the distinctiveness of this enzyme, this study reports converging evidence supporting loss of PRDX5 in aves. In-depth analysis revealed that this absence is proper to birds as PRDX5 appears to be conserved in non-avian amniotes. Finally, taking advantage of the in ovo electroporation technique, we validate the subcellular targeting of human PRDX5 in the chick embryo and bring forward this gain-of-function model as a potent way to study PRDX5 functions in vivo.

2-cyclohexylamino-5,8-dimethoxy-1,4-naphthoquinone inhibits LPS-induced BV2 microglial activation through MAPK/NF-kB signaling pathways

AIMS

To verify the effects of several 5,8-dimethoxy-1,4-naphthoquinone (DMNQ) derivatives on LPS-induced NO production, cellular ROS levels and cytokine expression in BV-2 microglial cells.

MAIN METHODS

An MTT assay and FACS flow cytometry were performed to assess the cellular viability and apoptosis and cellular ROS levels, respectively. To examine the expression of pro-inflammatory cytokines and cellular signaling pathways, semi-quantitative RT-PCR and Western blotting were also used in this study.

KEY FINDINGS

Among the six newly synthesized DMNQ derivatives, 2-cyclohexylamino-5,8-dimethoxy-1,4-naphthoquinone (R6) significantly inhibited the NO production, cellular ROS levels and the cytokines expression in BV-2 microglial cells, which stimulated by LPS. Signaling study showed that compound R6 treatment also significantly down-regulated the LPS-induced phosphorylation of MAPKs (ERK, JNK and p38) and decreased the degradation of IκB-α in BV2 microglial cells.

SIGNIFICANCE

Our findings demonstrate that our newly synthesized compound derived from DMNQ, 2-cyclohexylamino-5,8-dimethoxy-1,4-naphthoquinone (R6), might be a therapeutic agent for the treatment of glia-mediated neuroinflammatory diseases.

Peroxiredoxin 5 Protects TGF-β Induced Fibrosis by Inhibiting Stat3 Activation in Rat Kidney Interstitial Fibroblast Cells

Renal fibrosis is a common final pathway of end-stage kidney disease which is induced by aberrant accumulation of myofibroblasts. This process is triggered by reactive oxygen species (ROS) and proinflammatory cytokines generated by various source of injured kidney cells. Peroxiredoxin 5 (Prdx5) is a thiol-dependent peroxidase that reduces oxidative stress by catalyzing intramolecular disulfide bonds. Along with its antioxidant effects, expression level of Prdx5 also was involved in inflammatory regulation by immune stimuli. However, the physiological effects and the underlying mechanisms of Prdx5 in renal fibrosis have not been fully characterized. Sprague-Dawley rats were subjected to unilateral ureteral obstruction (UUO) for 1 or 7 days. For the in vitro model, NRK49F cells, a rat kidney interstitial fibroblast cell lines, were treated with transforming growth factor β (TGF-β) for 0, 1, 3, or 5 days. To access the involvement of its peroxidase activity in TGF-β induced renal fibrosis, wild type Prdx5 (WT) and double mutant Prdx5 (DM), converted two active site cysteines at Cys 48 and Cys 152 residue to serine, were transiently expressed in NRK49F cells. The protein expression of Prdx5 was reduced in UUO kidneys. Upregulation of fibrotic markers, such as fibronectin and alpha-smooth muscle actin (α-SMA), declined at 5 days in time point of higher Prdx5 expression in TGF-β treated NRK49F cells. The overexpression of wild type Prdx5 by transient transfection in NRK49F cells attenuated the TGF-β induced upregulation of fibronectin and α-SMA. On the other hand, the transient transfection of double mutant Prdx5 did not prevent the activation of fibrotic markers. Overexpression of Prdx5 also suppressed the TGF-β induced upregulation of Stat3 phosphorylation, while phosphorylation of Smad 2/3 was unchanged. In conclusion, Prdx5 protects TGF-β induced fibrosis in NRK49F cells by modulating Stat3 activation in a peroxidase activity dependent manner.

Overview on Peroxiredoxin

Peroxiredoxins (Prxs) are a very large and highly conserved family of peroxidases that reduce peroxides, with a conserved cysteine residue, designated the "peroxidatic" Cys (CP) serving as the site of oxidation by peroxides (Hall et al., 2011; Rhee et al., 2012). Peroxides oxidize the CP-SH to cysteine sulfenic acid (CP-SOH), which then reacts with another cysteine residue, named the "resolving" Cys (CR) to form a disulfide that is subsequently reduced by an appropriate electron donor to complete a catalytic cycle. This overview summarizes the status of studies on Prxs and relates the following 10 minireviews.

Multiple Roles of Peroxiredoxins in Inflammation

Inflammation is a pathophysiological response to infection or tissue damage during which high levels of reactive oxygen and nitrogen species are produced by phagocytes to kill microorganisms. Reactive oxygen and nitrogen species serve also in the complex regulation of inflammatory processes. Recently, it has been proposed that peroxiredoxins may play key roles in innate immunity and inflammation. Indeed, peroxiredoxins are evolutionarily conserved peroxidases able to reduce, with high rate constants, hydrogen peroxide, alkyl hydroperoxides and peroxynitrite which are generated during inflammation. In this minireview, we point out different possible roles of peroxiredoxins during inflammatory processes such as cytoprotective enzymes against oxidative stress, modulators of redox signaling, and extracellular pathogen- or damage-associated molecular patterns. A better understanding of peroxiredoxin functions in inflammation could lead to the discovery of new therapeutic targets.

Clinical relevance of thyroid cell models in redox research

Background

Thyroid-derived cell models are commonly used to investigate the characteristics of thyroid cancers. It is noteworthy that each in vitro single cell model system imitates only a few characteristics of thyroid cancer depending on e.g. source of cells or oncogene used to transform the cells.

Methods

In the current work we utilized rat thyroid cancer cell models to determine their clinical relevance in redox gene studies by comparing in vitro expression data to thyroid Oncomine microarray database. To survey the cell lines we analyzed mRNA expression of genes that produce superoxide anion (nox family), genes that catalyze destruction of superoxide anion to hydrogen peroxide (sod family), and genes that remove hydrogen peroxide from cellular environment (catalase, gpx family and prdx family).

Results

Based on the current results, rat thyroid PC Cl3, PC PTC1, PC E1A, or FRLT5 cell models can be used to study NOX2, NOX4, SOD2, SOD3, CATALASE, GPX1, GPX2, GPX5, PRDX2, and PRDX3 gene expression and function.

Conclusions

Redox gene expression in rat originated single cell model systems used to study human thyroid carcinogenesis corresponds only partly with human redox gene expression, which may be caused by differences in redox gene activation stimulus. The data suggest careful estimation of the data observed in rat thyroid in vitro models.

Electronic supplementary material

The online version of this article (doi:10.1186/s12935-015-0264-3) contains supplementary material, which is available to authorized users.

Peroxiredoxin II promotes hepatic tumorigenesis through cooperation with Ras/Forkhead box M1 signaling pathway

The current study was carried out to define the involvement of Peroxiredoxin (Prx) II in progression of hepatocellular carcinoma (HCC) and the underlying molecular mechanism(s). Expression and function of Prx II in HCC was determined using H-ras(G12V)-transformed HCC cells (H-ras(G12V)-HCC cells) and the tumor livers from H-ras(G12V)-transgenic (Tg) mice and HCC patients. Prx II was upregulated in H-ras(G12V)-HCC cells and H-ras(G12V)-Tg mouse tumor livers, the expression pattern of which highly similar to that of forkhead Box M1 (FoxM1). Moreover, either knockdown of FoxM1 or site-directed mutagenesis of FoxM1-binding site of Prx II promoter significantly reduced Prx II levels in H-ras(G12V)-HCC cells, indicating FoxM1 as a direct transcription factor of Prx II in HCC. Interestingly, the null mutation of Prx II markedly decreased the number and size of tumors in H-ras(G12V)-Tg livers. Consistent with this, knockdown of Prx II in H-ras(G12V)-HCC cells reduced the expression of cyclin D1, cell proliferation, anchorage-independent growth and tumor formation in athymic nude mice, whereas overexpression of Prx II increased or aggravated the tumor phenotypes. Importantly, the expression of Prx II was correlated with that of FoxM1 in HCC patients. The activation of extracellular signal-related kinase (ERK) pathway and the expression of FoxM1 and cyclin D1 were highly dependent on Prx II in H-ras(G12V)-HCC cells and H-ras(G12V)-Tg livers. Prx II is FoxM1-dependently-expressed antioxidant in HCC and function as an enhancer of Ras(G12V) oncogenic potential in hepatic tumorigenesis through activation of ERK/FoxM1/cyclin D1 cascade.

Human umbilical cord blood cells induce neuroprotective change in gene expression profile in neurons after ischemia through activation of Akt pathway

Human umbilical cord blood (HUCB) cell therapies have shown promising results in reducing brain infarct volume and most importantly in improving neurobehavioral function in rat permanent middle cerebral artery occlusion, a model of stroke. In this study, we examined the gene expression profile in neurons subjected to oxygen-glucose deprivation (OGD) with or without HUCB treatment and identified signaling pathways (Akt/MAPK) important in eliciting HUCB-mediated neuroprotective responses. Gene chip microarray analysis was performed using RNA samples extracted from the neuronal cell cultures from four experimental groups: normoxia, normoxia+HUCB, OGD, and OGD+HUCB. Both quantitative RT-PCR and immunohistochemistry were carried out to verify the microarray results. Using the Genomatix software program, promoter regions of selected genes were compared to reveal common transcription factor-binding sites and, subsequently, signal transduction pathways. Under OGD condition, HUCB cells significantly reduced neuronal loss from 68% to 44% [one-way ANOVA, F(3, 16)=11, p=0.0003]. Microarray analysis identified mRNA expression of Prdx5, Vcam1, CCL20, Alcam, and Pax6 as being significantly altered by HUCB cell treatment. Inhibition of the Akt pathway significantly abolished the neuroprotective effect of HUCB cells [one-way ANOVA, F(3, 11)=8.663, p=0.0031]. Our observations show that HUCB neuroprotection is dependent on the activation of the Akt signaling pathway that increases transcription of the Prdx5 gene. We concluded that HUCB cell therapy would be a promising treatment for stroke and other forms of brain injury by modifying acute gene expression to promote neural cell protection.

CCDC88B is a novel regulator of maturation and effector functions of T cells during pathological inflammation

Kennedy et al. identify a mutation in coiled-coil domain containing protein 88b (Ccdc88b) that confers protection against lethal neuroinflammation during experimental cerebral malaria. CCDC88B is expressed in immune cells and regulates T cell maturation and effector functions. In humans, the CCDC88B gene maps to a locus associated with susceptibility to several inflammatory and autoimmune disorders.

We used a genome-wide screen in mutagenized mice to identify genes which inactivation protects against lethal neuroinflammation during experimental cerebral malaria (ECM). We identified an ECM-protective mutation in coiled-coil domain containing protein 88b (Ccdc88b), a poorly annotated gene that is found expressed specifically in spleen, bone marrow, lymph nodes, and thymus. The CCDC88B protein is abundantly expressed in immune cells, including both CD4⁺ and CD8⁺ T lymphocytes, and in myeloid cells, and loss of CCDC88B protein expression has pleiotropic effects on T lymphocyte functions, including impaired maturation in vivo, significantly reduced activation, reduced cell division as well as impaired cytokine production (IFN-γ and TNF) in response to T cell receptor engagement, or to nonspecific stimuli in vitro, and during the course of P. berghei infection in vivo. This identifies CCDC88B as a novel and important regulator of T cell function. The human CCDC88B gene maps to the 11q13 locus that is associated with susceptibility to several inflammatory and auto-immune disorders. Our findings strongly suggest that CCDC88B is the morbid gene underlying the pleiotropic effect of the 11q13 locus on inflammation.

Morphological changes and altered expression of antioxidant proteins in a heterozygous dynein mutant; a mouse model of spinal muscular atrophy

OBJECTIVE

There is increased evidence that oxidative stress is involved in exacerbations of neurodegenerative diseases and spinal muscular atrophies.

METHODS

We examined changes in morphology and expression of antioxidant proteins and peroxiredoxins in motor neurons of lumbar spinal cord, dorsal root ganglion sensory neurons, macroglial cells and quadriceps muscles of newborn heterozygous Loa/+ mice ("legs at odd angles"), a mouse model for early onset of the spinal muscular atrophy with lower extremity predominance (SMA-LED).

RESULTS

Our data indicate that newborn Loa-mice develop: neuroinflammation of the sensory and motor neurons; muscular inflammation with atrophic and denervated myofibers; increased expression of neuronal mitochondrial peroxiredoxins (Prxs) 3, 5 and cytoplasmic Prx 6 in motor and sensory neurons, myofibers, fibroblasts of perimysium and chondrocytes of cartilage; and decreased expression of Prx 6 by glial cells and in extracellular space surrounding motor neurons.

CONCLUSION

The decrease in expression of Prx 6 by glial cells and extracellular Prx 6 secretion in early stages of the pathological conditions is consistent with the hypothesis that chronic oxidative stress may lead to neurodegeneration of motor neurons and exacerbation of the pathology.

Prx I suppresses K-ras-driven lung tumorigenesis by opposing redox-sensitive ERK/cyclin D1 pathway

AIMS

Coupled responses of mutated K-ras and oxidative stress are often an important etiological factor in non-small-cell lung cancer (NSCLC). However, relatively few studies have examined the control mechanism of oxidative stress in oncogenic K-ras-driven NSCLC progression. Here, we studied whether the redox signaling pathway governed by peroxiredoxin I (Prx I) is involved in K-ras(G12D)-mediated lung adenocarcinogenesis.

RESULTS

Using human-lung adenocarcinoma tissues and lung-specific K-ras(G12D)-transgenic mice, we found that Prx I was significantly up-regulated in the tumor regions via activation of nuclear erythroid 2-related factor 2 (Nrf2) transcription. Interestingly, the increased reactive oxygen species (ROS) by null mutation of Prx I greatly promoted K-ras(G12D)-driven lung tumorigenesis in number and size, which appeared to require the activation of the ROS-dependent extracellular signal-regulated kinase (ERK)/cyclin D1 pathway.

INNOVATION

Taken together, these results suggest that Prx I functions as an Nrf2-dependently inducible tumor suppressant in K-ras-driven lung adenocarcinogenesis by opposing ROS/ERK/cyclin D1 pathway activation.

CONCLUSION

These findings provide a better understanding of oxidative stress-mediated lung tumorigenesis.