Free radical mediated peroxidative damage in systemic lupus erythematosus

Unveiling the role of mtDNA in Liver-Kidney Crosstalk: Insights from trichloroethylene hypersensitivity syndrome

In specific pathological conditions, addressing liver injury may yield favorable effects on renal function through the phenomenon of liver-kidney crosstalk. Mitochondrial DNA (mtDNA) possesses the capability to trigger downstream pathways of inflammatory cytokines, ultimately leading to immune-mediated organ damage. Consequently, understanding the intricate molecular mechanisms governing mtDNA involvement in diseases characterized by liver-kidney crosstalk is of paramount significance. This study seeks to elucidate the role of mtDNA in conditions marked by liver-kidney crosstalk. In previous clinical cases, it has been observed that patients with Trichloroethylene Hypersensitivity Syndrome (TCE-HS) who experience severe liver injury often also exhibit renal injury. In this study, patients diagnosed with trichloroethylene hypersensitivity syndrome were recruited from Shenzhen Occupational Disease Control Center. And Balb/c mice were treated with trichloroethylene. The correlation between liver and kidney injuries in patients with TCE-HS was assessed using Enzyme-Linked Immunosorbent Assay (ELISA). Alterations in mtDNA levels were examined in mouse hepatocytes, red blood cells (RBCs), and renal tubular epithelial cells utilizing immunofluorescence and PCR techniques. TCE-sensitized mice exhibited a significant increase in reactive oxygen species (ROS) and the opening of the mitochondrial permeability transition pore in hepatocytes, resulting in the release of mtDNA. Furthermore, heightened levels of mtDNA and Toll-like Receptor 9 (TLR9) expression were observed in RBCs. Additional experiments demonstrated elevated expression of TLR9 and its downstream mediator MyD88 in renal tubule epithelial cells of TCE-sensitized mice. In vitro investigations confirmed that mtDNA activates the TLR9 pathway in TCMK-1 cells. Collectively, these results suggest that mtDNA released from mitochondrial damage in hepatocytes is carried by RBCs to renal tubular epithelial cells and mediates inflammatory injury in renal tubular epithelial cells through activation of the TLR9 receptor.

The role of microbiota and oxidative stress axis and the impact of intravenous immunoglobulin in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by widespread inflammation affecting various organs. This review discusses the role of oxidative stress and gut microbiota in the pathogenesis of SLE and evaluates the therapeutic potential of intravenous immunoglobulins (IVIg). Oxidative stress contributes to SLE by causing impairment in the function of mitochondria, resulting in reactive oxygen species production, which triggers autoantigenicity and proinflammatory cytokines. Gut microbiota also plays a significant role in SLE. Dysbiosis has been associated to disease's onset and progression. Moreover, dysbiosis exacerbates SLE symptoms and influences systemic immunity, leading to a breakdown in bacterial tolerance and an increase in inflammatory responses. High-dose IVIg has emerged as a promising treatment for refractory cases of SLE. The beneficial effects of IVIg are partly due to its antioxidant property, reducing oxidative stress markers and modulating the immune responses. Additionally, IVIg can normalize the gut flora, as demonstrated in a case of severe intestinal pseudo-obstruction. In summary, both oxidative stress and dysregulation of microbiota are pivotal in the pathogenesis of SLE. The use of IVIg may improve the disease's outcome. Future research should be directed to elucidating the precise mechanisms by which oxidative stress and microbiota are linked with autoimmunity in SLE in developing targeted therapies.

Plasma/Serum Oxidant Parameters in Systemic Lupus Erythematosus Patients: A Systematic Review and Meta-Analysis

Most published results have revealed variations in the association of serum/plasma levels of malondialdehyde (MDA), apolipoprotein B (ApoB), and oxidized low-density lipoprotein (OxLDL) and systemic lupus erythematosus (SLE). This study was performed to establish MDA, ApoB, and OxLDL levels in systemic lupus erythematosus (SLE) patients. Electronic databases were searched for the included articles up to 27th February 2023. The meta-analysis included 48 articles with 2358 SLE patients and 2126 healthy controls considered for MDA, ApoB, and OxLDL levels. There were significantly higher MDA, ApoB, and OxLDL levels in SLE patients than those in the control groups. Subgroup analysis indicated that European/American SLE patients and patients of both ages <36 and ≥36 exhibited higher MDA, ApoB, and OxLDL levels. Arab and Asian SLE patients had higher ApoB and MDA/OxLDL levels. African SLE patients recorded higher OxLDL levels than the control groups. SLE patients with a body mass index (BMI) of ≥23 and a disease duration of <10 recorded significantly higher MDA, ApoB, and OxLDL levels. Patients with systemic lupus erythematosus disease activity index (SLEDAI) ≥8 of SLE had higher MDA and ApoB levels, whereas SLE patients with SLEDAI <8 showed significantly higher ApoB levels. Patients with BMI <23 of SLE had higher MDA and OxLDL levels. This study established significantly higher MDA, ApoB, and OxLDL levels in SLE patients, suggesting a possible role of MDA, ApoB, and OxLDL in the disease.

Mitochondrial Dysfunction and Fatigue in Sjögren's Disease

Objectives

Sjögren's disease (SjD) is a common exocrine disorder typified by chronic inflammation and dryness, but also profound fatigue, suggesting a pathological basis in cellular bioenergetics. In healthy states, damaged or dysfunctional mitochondrial components are broken down and recycled by mitophagy, a specialized form of autophagy. In many autoimmune disorders, however, evidence suggests that dysfunctional mitophagy allows poorly functioning mitochondria to persist and contribute to a cellular milieu with elevated reactive oxygen species. We hypothesized that mitophagic processes are dysregulated in SjD and that dysfunctional mitochondria contribute to overall fatigue. We sought to link fatigue with mitochondrial dysfunction directly in SjD, heretofore unexamined, and further sought to assess the pathogenic extent and implications of dysregulated mitophagy in SjD.

Methods

We isolated pan T cells via negative selection from the peripheral blood mononuclear cells of 17 SjD and 8 age-matched healthy subjects, all of whom completed fatigue questionnaires prior to phlebotomy. Isolated T cells were analyzed for mitochondrial oxygen consumption rate (OCR) and glycolysis using Seahorse, and linear correlations with fatigue measures were assessed. A mitophagy transcriptional signature in SjD was identified by reanalysis of whole-blood microarray data from 190 SjD and 32 healthy subjects. Differential expression analyses were performed by case/control and subgroup analyses comparing SjD patients by mitophagy transcriptional cluster against healthy subjects followed by bioinformatic interpretation using gene set enrichment analysis.

Results

Basal OCR, ATP-linked respiration, maximal respiration, and reserve capacity were significantly lower in SjD compared to healthy subjects with no observed differences in non-mitochondrial respiration, basal glycolysis, or glycolytic stress. SjD lymphocytic mitochondria show structural alterations compared to healthy subjects. Fatigue scores related to pain/discomfort in SjD correlated with the altered OCR. Results from subgroup analyses by mitophagic SjD clusters revealed highly variable inter-cluster differentially expressed genes (DEGs) and expanded the number of SjD-associated gene targets by tenfold within the same dataset.

Conclusion

Mitochondrial dysfunction, associated with fatigue, is a significant problem in SjD and warrants further investigation.

Immmunometabolism of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a potentially fatal chronic autoimmune disease which is underlain by complex dysfunction of the innate and adaptive immune systems. Although a series of well-defined genetic and environmental factors have been implicated in disease etiology, neither the development nor the persistence of SLE is well understood. Given that several disease susceptibility genes and environmental factors interact and influence inflammatory lineage specification through metabolism, the field of immunometabolism has become a forefront of cutting edge research. Along these lines, metabolic checkpoints of pathogenesis have been identified as targets of effective therapeutic interventions in mouse models and validated in clinical trials. Ongoing studies focus on mitochondrial oxidative stress, activation of the mechanistic target of rapamycin, calcium signaling, glucose utilization, tryptophan degradation, and metabolic cross-talk between gut microbiota and the host immune system.

Profiling the antioxidant biomarkers in marine fish larvae: a comparative assessment of different storage conditions to select the optimal strategy

Research on antioxidant biomarkers can generate profound insights into the defense mechanisms of fish larvae against different stressors and can reveal manipulation strategies for improved growth and survival. However, the number of samples to process and unavailability of required infrastructure in larval-rearing facilities limit the immediate processing, requiring the preservation of specimens. Silver pompano (Trachinotus blochii), a potential marine aquaculture species, shows a low larval survival rate due to poorly developed antioxidant mechanism. In this context, 39 storage conditions, including three storage temperatures and different buffers, were scrutinized to select the most suitable preservation strategy for five important antioxidant biomarkers of fish larvae, viz. catalase activity, superoxide dismutase (SOD) activity, measurement of lipid peroxidation, reduced glutathione (GSH), and ascorbic acid contents. The paper proposes the optimum larval storage conditions for these five evaluated antioxidant biomarkers to generate similar results in preserved and non-preserved larval samples. Larval samples preserved in PBS at lower temperatures (- 20 °C and - 80 °C) are recommended for evaluating catalase activity and ascorbic acid content. Catalase activity can also be evaluated by preserving the larval samples at - 20 °C or - 80 °C without buffers. Larval samples held in PBS or without any buffers at - 20 °C and at - 80 °C were found to be suitable for SOD and GSH evaluation, respectively. Preservation in 50% glacial acetic acid at - 80 °C or - 20 °C was preferred for the lipid peroxidation assays. Apart from methodological perspectives, the paper provides insights into the dynamics of larval antioxidant profiles of T. blochii, for the first time.

Exploring the relationship between oxidative stress status and inflammatory markers during primary Sjögren's syndrome: A new approach for patient monitoring

INTRODUCTION

Primary Sjögren's syndrome (pSS) is a chronic inflammatory disease primarily affects exocrine glands dysfunction. Oxidative stress (OS) is a phenomenon occurring as a result of an imbalance between the generation of free radicals and antioxidant defense system. Hence, we aimed to establish the status of OS and inflammatory response according to the pSS disease activity index. In this context, we investigated malondialdehyde (MDA), and antioxidant enzymes during pSS. The possible association between MDA and nitric oxide (NO) levels and between MDA and some pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IL-33).

METHODS

The study has been conducted on 53 pSS patients. The antioxidant enzymes, represented by glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD), were estimated by a colorimetric activity kit. Whereas, MDA value was assessed by measuring thiobarbituric acid reactive substances. Moreover, pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IL-33) and NO were respectively quantified by enzyme-linked immunosorbent assays (ELISA) and the modified Griess.

RESULTS

Interestingly, we report a notable reduction in our pSS patients' antioxidant enzyme activity, while NO, MDA and proinflammatory cytokines values were significantly increased. pSS patients with higher disease activity had much stronger increases in NO and MDA levels. No significant difference was assessed in CRP level. Additionally, substantial significant correlations between plasmatic NO and MDA levels and between MDA, NO and IL-1β, IL-6, TNF-α cytokines were reported. However, no significant association was found between NO, MDA and IL-33 concentrations.

CONCLUSION

Collectively, our data showed altered oxidant-antioxidant balance in pSS patients. MDA, NO, IL-1β, IL-6, TNF-α seem to be good indicators in monitoring disease activity. Oxidative stress was closely related to inflammation in pSS. Exploiting this relationship might provide valuable indicators in the follow-up and prognosis of pSS with a potential therapeutic value.

Neutrophil Extracellular Traps have DNAzyme activity that drives bactericidal potential

The mechanisms of bacterial killing by neutrophil extracellular traps (NETs) are unclear. DNA, the largest component of NETs is believed to merely be a scaffold with minimal antimicrobial activity through the charge of the backbone. Here, we report that NETs DNA is beyond a scaffold and produces hydroxyl free radicals through the spatially concentrated G-quadruplex/hemin DNAzyme complexes, driving bactericidal effects. Immunofluorescence staining showed colocalization of G-quadruplex and hemin in extruded NETs DNA, and Amplex UltraRed assay portrayed its peroxidase activity. Proximity labeling of bacteria revealed localized concentration of radicals resulting from NETs bacterial trapping. Ex vivo bactericidal assays revealed that G-quadruplex/hemin DNAzyme is the primary driver of bactericidal activity in NETs. NETs are DNAzymes that may have important biological consequences.

Increased carotid intima-media thickening and antioxidized low-density lipoprotein in an anti-Ro60 SLE autoantibody subset

Objective

Premature atherosclerosis is associated with systemic lupus erythematosus (SLE). We have previously shown an association of anti-Ro60/La/Ro52 with antioxidized low-density lipoprotein (LDL) in SLE. Here, we hypothesized that carotid intima-media thickening (CIMT) would be associated with antioxidized LDL (anti-oxLDL)/antilipoprotein lipase (ALPL) in a specific SLE autoantibody subset (anti-Ro60 positive, anti-RNP positive, anti-SmRNP positive, or extractable nuclear antigen antibody negative).

Methods

We carried out a case-control study (one time-point testing) of CIMT, ALPL, anti-oxLDL, anti-low density lipoprotein (ALDL), and anti-LDL in 114 SLE patients and 117 age/sex-matched controls. The levels of total cholesterol, LDL, high-density lipoprotein (HDL), triglycerides, and HDL-Trig were also measured. A student's t-test was used for statistical analysis.

Results

Interestingly, the level of CIMT was highest in the SLE subset with anti-Ro60 (23/114). CIMT and anti-oxLDL were statistically significantly elevated in the anti-Ro60 SLE subset (1.3 ± 1.66, p < 0.01; 0.26 ± 0.16, p < 0.002, respectively) compared with controls (0.54 ± 1.26; 0.165 ± 0.13, respectively), but not anti-LPL/anti-LDL. CIMT was significantly elevated (0.9 ± 1.71; p < 0.05) in the SLE subset without antiextractable nuclear antigen (ENA) (63/114) compared with controls. The other antibodies in this subset were not statistically different from other SLE subsets or controls. Only antioxLDL was significantly elevated (0.29 ± 0.27; p < 0.005) in the SLE subset with anti-RNP (14/114) compared with controls, while none were elevated in the anti-SmRNP subset (6/114). We did not find any significant differences in lipids between the various SLE subsets.

Conclusion

CIMT segregates in anti-Ro and ENA negative groups either with or without anti-oxLDL. It will be clinically important if cardiovascular events are augmented in the SLE anti-Ro subset having elevated antioxidized LDL antibodies.

Autoimmunity: A New Focus on Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) has long been considered a benign, chronic inflammatory, and hyperplastic disease. Recent studies have shown that autoimmune-related mechanisms are involved in the pathology of nasal polyps. Activated plasma cells, eosinophils, basophils, innate type 2 lymphocytes, mast cells, and proinflammatory cytokine in polyp tissue indicate the mobilization of innate and adaptive immune pathways during polyp formation. The discovery of a series of autoantibodies further supports the autoimmune nature of nasal polyps. Local homeostasis dysregulation, infection, and chronic inflammation may trigger autoimmunity through several mechanisms, including autoantigens overproduction, microbial translocation, molecular mimicry, superantigens, activation or inhibition of receptors, bystander activation, dysregulation of Toll-Like Receptors (TLRs), epitope spreading, autoantigens complementarity. In this paper, we elaborated on the microbiome-mediated mechanism, abnormal host immunity, and genetic changes to update the role of autoimmunity in the pathogenesis of chronic rhinosinusitis with nasal polyps.

Essential Trace Element Status in Systemic Lupus Erythematosus: a Meta-analysis Based on Case-Control Studies

The homeostasis of trace elements is essential to regulate different aspects of the immune system and might play important roles in systemic lupus erythematosus (SLE). However, epidemiological evidences that compared the level of essential trace elements in SLE patients and healthy controls (HCs) did not reach a consensus. This was the first meta-analysis to comprehensively assess the level of zinc (Zn), copper (Cu), iron (Fe), and selenium (Se) in SLE and HCs. PubMed, Embase, and Web of Science were systematically searched until April 2022 to find relevant literatures. The PRISMA statement 2020 was followed to make sure the quality of reporting a meta-analysis. The outcomes were assessed by pooled standardized mean difference (SMD) and 95% confidence intervals (CIs). Finally, eleven articles with 1262 subjects were included in the meta-analysis. Significantly lower levels of Zn (SMD = -0.709; 95% CI: -1.173, -0.245; P = 0.003) and Fe (SMD = -1.783; 95% CI: -2.756, -0.809; P = 0.000) were found in SLE compared with HCs. Higher levels of Cu (SMD = 0.808; 95% CI: 0.234, 1.382; P = 0.006) were found in SLE patients. In addition, compared with HCs, Fe and Zn were lower in SLE patients in Asia and Cu was higher in SLE patients in Europe. However, no significant difference was observed in the level of Se (SMD = -0.251; 95% CI: -1.087, 0.586; P = 0.557). Above all, SLE patients exhibited lower Zn and Fe and increased Cu concentrations compared with HCs. Further studies are warranted to investigate the mechanism of Zn, Cu, and Fe in SLE patients.

Polystyrene microplastics mediate inflammatory responses in the chicken thymus by Nrf2/NF-κB pathway and trigger autophagy and apoptosis

Microplastics (MPs) are now a hot environmental contaminant. However, researchers paid little attention to their effects on immune organs such as the thymus. Here, we exposed chickens to a concentration gradient of polystyrene microplastics (PS-MPs) and then followed the decrease in the thymus index. HE staining showed cellular infiltration in the thymus. The assay kit corroborated that PS-MPs impelled oxidative stress in the thymus: increased MDA levels, downregulated antioxidants such as SOD, CAT, and GSH, and significantly undermined total antioxidant capacity. Western blotting and qRT-PCR results showed that Nrf2/NF-κB, Bcl-2/Bax, and AKT signaling pathways were activated in the thymus after exposure to PS-MPs. It stimulated the increased expression of downstream such as IL-1β, caspase-3, and Beclin1, triggering thymus inflammation, apoptosis, and autophagy. This study provides new insights into the field of microplastic immunotoxicity and highlights potential environmental hazards in poultry farming.

The Genetic Diversity and Dysfunctionality of Catalase Associated with a Worse Outcome in Crohn's Disease

Chronic gut inflammation in Crohn’s disease (CD) is associated with an increase in oxidative stress and an imbalance of antioxidant enzymes. We have previously shown that catalase (CAT) activity is permanently inhibited by CD. The purpose of the study was to determine whether there is any relationship between the single nucleotide polymorphisms (SNPs) in the CAT enzyme and the potential risk of CD associated with high levels of oxidative stress. Additionally, we used protein and regulation analyses to determine what causes long-term CAT inhibition in peripheral white mononuclear cells (PWMCs) in both active and inactive CD. We first used a retrospective cohort of 598 patients with CD and 625 age-matched healthy controls (ENEIDA registry) for the genotype analysis. A second human cohort was used to study the functional and regulatory mechanisms of CAT in CD. We isolated PWMCs from CD patients at the onset of the disease (naïve CD patients). In the genotype-association SNP analysis, the CAT SNPs rs1001179, rs475043, and rs525938 showed a significant association with CD (p < 0.001). Smoking CD patients with the CAT SNP rs475043 A/G genotype had significantly more often penetrating disease (p = 0.009). The gene expression and protein levels of CAT were permanently reduced in the active and inactive CD patients. The inhibition of CAT activity in the PWMCs of the CD patients was related to a low concentration of CAT protein caused by the downregulation of CAT-gene transcription. Our study suggests an association between CAT SNPs and the risk of CD that may explain permanent CAT inhibition in CD patients together with low CAT gene and protein expression.

Dietary Glutamine Inclusion Regulates Immune and Antioxidant System, as Well as Programmed Cell Death in Fish to Protect against Flavobacterium columnare Infection

The susceptibility of animals to pathogenic infection is significantly affected by nutritional status. The present study took yellow catfish (Pelteobagrus fulvidraco) as a model to test the hypothesis that the protective roles of glutamine during bacterial infection are largely related to its regulation on the immune and antioxidant system, apoptosis and autophagy. Dietary glutamine supplementation significantly improved fish growth performance and feed utilization. After a challenge with Flavobacterium columnare, glutamine supplementation promoted il-8 and il-1β expression via NF-κB signaling in the head kidney and spleen, but inhibited the over-inflammation in the gut and gills. Additionally, dietary glutamine inclusion also enhanced the systematic antioxidant capacity. Histological analysis showed the protective role of glutamine in gill structures. Further study indicated that glutamine alleviated apoptosis during bacterial infection, along with the reduced protein levels of caspase-3 and the reduced expression of apoptosis-related genes. Moreover, glutamine also showed an inhibitory role in autophagy which was due to the increased activation of the mTOR signaling pathway. Thus, our study for the first time illustrated the regulatory roles of glutamine in the fish immune and antioxidant system, and reported its inhibitory effects on fish apoptosis and autophagy during bacterial infection.

The Programming of Antioxidant Capacity, Immunity, and Lipid Metabolism in Dojo Loach (Misgurnus anguillicaudatus) Larvae Linked to Sodium Chloride and Hydrogen Peroxide Pre-treatment During Egg Hatching

Non-nutritional stress during early life period has been reported to promote the metabolic programming in fish induced by nutritional stimulus. Sodium chloride (NaCl) and hydrogen peroxide (H₂O₂) have been widely applied during fish egg hatching, but the influences on health and metabolism of fish in their later life remain unknown. In the present study, H₂O₂ treatment at 400mg/L but not 200mg/L significantly increased the loach hatchability and decreased the egg mortality, while NaCl treatment at 1,000 and 3,000mg/L showed no significant influences on the loach hatchability nor egg mortality. Further studies indicated that 400mg/L H₂O₂ pre-treatment significantly enhanced the antioxidant capacity and the mRNA expression of genes involved in immune response of loach larvae, accompanied by the increased expression of genes involved in fish early development. However, the expression of most genes involved in lipid metabolism, including catabolism and anabolism of loach larvae, was significantly upregulated after 200mg/L H₂O₂ pre-treatment. NaCl pre-treatment also increased the expression of antioxidant enzymes; however, only the expression of C1q within the detected immune-related genes was upregulated in loach larvae. One thousand milligram per liter NaCl pre-treatment significantly increased the expression of LPL and genes involved in fish early development. Thus, our results suggested the programming roles of 400mg/L H₂O₂ pre-treatment during egg hatching in enhancing antioxidant capacity and immune response of fish larvae via promoting fish early development.

In Vitro Anti-Epstein Barr Virus Activity of Olea europaea L. Leaf Extracts

Olea europaea L. var. sativa (OESA) preparations are widely used in traditional medicine in the Mediterranean region to prevent and treat different diseases. In this research, olive extracts derived from the leaves of the OESA tree have been screened for antioxidant activity by two methods: the DPPH free radical scavenging assay (DPPH) and the Ferric reducing antioxidant power (FRAP) assay. The DPPH assay showed that OESA possesses a stronger antioxidant activity (84%) at 1 mg/mL while the FRAP method showed a strong metal ion chelating activity (90%) at 1 mg/mL. The low IC₅₀ values, obtained by two different methods, implies that OESA has a noticeable effect on scavenging free radicals comparable to standards. During EBV infection, the free radicals increased triggering lipid oxidation. Therefore, the monitoring of the secondary lipid peroxidation products was done by measuring malonaldehyde (MDA) and conjugated dienes (DC). The simultaneous treatment of Raji cells with OESA and TPA, as an inductorof the lytic cycle, generated a significant decrease in MDA levels and DC (p < 0.05). Besides, Raji cells simultaneously exposed to TPA and OESA exhibited a percentage of EBV-positive fluorescence cells lower than TPA treated cells (**** p < 0.0001). This suggests that OESA treatment has a protective effect against EBV lytic cycle induction.

And Yet It Moves: Oxidation of the Nuclear Autoantigen La/SS-B Is the Driving Force for Nucleo-Cytoplasmic Shuttling

Decades ago, we and many other groups showed a nucleo-cytoplasmic translocation of La protein in cultured cells. This shuttling of La protein was seen after UV irradiation, virus infections, hydrogen peroxide exposure and the Fenton reaction based on iron or copper ions. All of these conditions are somehow related to oxidative stress. Unfortunately, these harsh conditions could also cause an artificial release of La protein. Even until today, the shuttling and the cytoplasmic function of La/SS-B is controversially discussed. Moreover, the driving mechanism for the shuttling of La protein remains unclear. Recently, we showed that La protein undergoes redox-dependent conformational changes. Moreover, we developed anti-La monoclonal antibodies (anti-La mAbs), which are specific for either the reduced form of La protein or the oxidized form. Using these tools, here we show that redox-dependent conformational changes are the driving force for the shuttling of La protein. Moreover, we show that translocation of La protein to the cytoplasm can be triggered in a ligand/receptor-dependent manner under physiological conditions. We show that ligands of toll-like receptors lead to a redox-dependent shuttling of La protein. The shuttling of La protein depends on the redox status of the respective cell type. Endothelial cells are usually resistant to the shuttling of La protein, while dendritic cells are highly sensitive. However, the deprivation of intracellular reducing agents in endothelial cells makes endothelial cells sensitive to a redox-dependent shuttling of La protein.

Two Be or Not Two Be: The Nuclear Autoantigen La/SS-B Is Able to Form Dimers and Oligomers in a Redox Dependent Manner

According to the literature, the autoantigen La is involved in Cap-independent translation. It was proposed that one prerequisite for this function is the formation of a protein dimer. However, structural analyses argue against La protein dimers. Noteworthy to mention, these structural analyses were performed under reducing conditions. Here we describe that La protein can undergo redox-dependent structural changes. The oxidized form of La protein can form dimers, oligomers and even polymers stabilized by disulfide bridges. The primary sequence of La protein contains three cysteine residues. Only after mutation of all three cysteine residues to alanine La protein becomes insensitive to oxidation, indicating that all three cysteines are involved in redox-dependent structural changes. Biophysical analyses of the secondary structure of La protein support the redox-dependent conformational changes. Moreover, we identified monoclonal anti-La antibodies (anti-La mAbs) that react with either the reduced or oxidized form of La protein. Differential reactivities to the reduced and oxidized form of La protein were also found in anti-La sera of autoimmune patients.

Heme-Oxygenase-1 Is Decreased in Circulating Monocytes and Is Associated With Impaired Phagocytosis and ROS Production in Lupus Nephritis

Lupus nephritis (LN) is one of the most serious manifestations of systemic lupus erythematosus (SLE). Based on studies showing the potential role of heme oxygenase-1 (HO-1), an enzyme that catalyzes the degradation of heme and has anti-inflammatory properties in SLE development, we decided to explore HO-1 in LN. Accordingly, we evaluated HO-1 levels and function in circulating and infiltrating monocytes and neutrophils of LN patients. HO-1 levels were assessed in peripheral monocytes of LN patients and controls by flow cytometry and immunofluorescence microscopy. Phagocytosis and the production of reactive oxygen species (ROS) were evaluated to determine the effect of HO-1 in monocyte function. In addition, renal biopsies with proliferative LN were used to identify HO-1 in infiltrating cells and renal tissue by immunofluorescence and immunohistochemistry. Biopsies of healthy controls (HC) and patients who underwent nephrectomy were included as controls. Circulating pro-inflammatory monocytes and activated neutrophils were increased in LN patients. HO-1 levels were decreased in all subsets of monocytes and in activated neutrophils. LN monocytes showed increased phagocytosis and higher production of ROS than those of HC. When HO-1 was induced, phagocytosis and ROS levels became similar to those of HC. HO-1 was mostly expressed in renal tubular epithelial cells (RTEC). Renal tissue of LN patients showed lower levels of HO-1 than HC, whereas infiltrating immune cells of LN showed lower levels of HO-1 than biopsies of patients who had renal surgery. HO-1 is decreased in circulating monocytes and activated neutrophils of LN patients. HO-1 levels modulate the phagocytosis of LN monocytes and ROS production. HO-1 expression in RTEC might be an attempt of self-protection from inflammation.

Lawsonia inermis essential oil: extraction optimization by RSM, antioxidant activity, lipid peroxydation and antiproliferative effects

BACKGROUND

The present study was focused on the optimization of yield of the essential oil extraction from leaves of Lawsonia inermis, and the determination of chemical composition, antioxidant activities, and lipid peroxydation and antiproliferative effects.

METHODS

Henna essential oil (HeEO) were extracted by hydrodistillation; the identification of the chemical composition were done by GC/MS method. HeEO was analyzed for antioxidant power in: (1) chemical system by the DPPH test, the ABTS test and the total antioxidant activity test; and (2) in biological system by lipid peroxydation tests (MDA and DC) in cells culture. The cytotoxicity effects of HeEO were assessed using MTT assay against Raji and HeLa cell lines.

RESULTS

The optimal extraction yield was 6.8 g/100 g d.b. HeEO showed a remarkable anti-oxidant activities including DDPH (42%), ABTS (87%) and the power of ammonium phosphomolybdate (2992 ± 230 mg of HeEO by equivalent to 1 mg of vitamin C in terms of total antioxidant power).

CONCLUSION

Beyond notable antioxidant activities of the HeEo, our results showed a significant decrease in the production of ERO in the Raji cell line. The anti-tumor power of the Henna essential oil shows an interesting cytotoxicity effect (IC₅₀ at 0.26 μg/mL for Raji and at 1.43 μg/mL for HeLa) with a total mortality percentage reaching 60%, for both.

Altered Tregs and oxidative stress in pregnancy associated lupus

AIM

SLE is a systemic autoimmune disease generally affecting woman in the reproductive age. It is associated with an altered level of Tregs and oxidative stress while an increase in Tregs, and different antioxidant mechanisms to combat oxidative stress are essential for successful pregnancy. Hence, this study aims to determine the level of CD4⁺ and CD8⁺ Tregs and oxidative stress in pregnant lupus patients.

METHODS

Ten healthy and 10 pregnant lupus volunteers from the North Indian population, within the age group of 20-30 years were enrolled in the study. All the patients were non-smokers, non-alcoholics and were not associated or undergoing therapy for any other disease. They had a SLEDAI of 37.4 ± 7.32 with 5.2 ± 1.93 years of disease duration. Oxidative stress was determined by measuring the enzyme activity of anti-oxidant enzymes (catalase, superoxide dismutase and glutathione peroxidase) and the level of reduced glutathione and lipids peroxidised, spectrophotometrically. Flowcytometry was performed for immunophenotyping to determine CD8⁺ and CD4⁺ Tregs.

RESULTS

Elevated CD8⁺ Tregs and diminished CD4⁺ Tregs were observed in pregnant lupus patients. Oxidative stress was significantly increased as the activities of anti-oxidant enzymes and level of reduced glutathione was considerably diminished. There was a substantial increase in the amount of lipids peroxidised.

CONCLUSION

Pregnant lupus patients undergo considerable level of oxidative stress in comparison to healthy pregnant woman. The decreased level of CD4⁺ Tregs and an increase in CD8⁺ Tregs might be another important factor responsible for pregnancy associated complications. Hence, lupus leads to alterations in the necessary conditions for a successful pregnancy, which might eventually cause higher mortality, morbidity and associated complications.

Strawberries decrease circulating levels of tumor necrosis factor and lipid peroxides in obese adults with knee osteoarthritis

OBJECTIVE

Knee osteoarthritis (OA) is increasingly prevalent in obese people, who often have high cardio-metabolic risk factors. Among the few available non-surgical approaches, nutraceuticals have gained popularity, and dietary berries have mitigated arthritis symptoms in observational and animal studies. Clinical studies in OA are sparse, but recently we reported that strawberry supplementation can mitigate pain and reduce inflammatory markers in adults with knee OA. This study extends those observations.

METHODS

We conducted a randomized cross-over double-blind placebo-controlled trial on the effects of dietary freeze-dried strawberries on obesity-related hormones, biomarkers of inflammation and lipid peroxidation. Seventeen subjects (4 men, 13 women; age 57 ± 3 year) were randomized to strawberry supplements (50 g day-1 for 12 weeks) vs. placebo (50 g day-1, matched for calories and fiber), for two 12-week intervention periods, separated by 2-week washout phase.

RESULTS

Among 24 biomarkers of inflammation examined (Bioplex-Pro human inflammation panel), 12 were detectable in all samples. Among these, high-sensitivity TNF-α (hs-TNF-α) and the soluble tumor necrosis factor receptor (sTNF-R2) were significantly decreased after strawberry consumption (p < 0.05). There were no changes in other biomarkers of the TNF super family, such as APRIL and BAFF. Among serum biomarkers of oxidative stress, 4-hydroxy-2-nonenal (4-HNE) and conjugated dienes were also reduced (p < 0.05). No changes were observed in body weight, serum obesity-related hormones, or osteocalcin.

CONCLUSION

Strawberries lowered TNF-α, and lipid peroxidation products in obese adults with knee OA. Since, they also mitigate pain, these findings merit further investigation in larger trials.

Anti-Ro and Concomitant Anti-La Autoantibodies Strongly Associated With Anti-oxLDL or Anti-Phospholipid Antibody in Systemic Lupus Erythematosus

BACKGROUND

Premature atherosclerosis is observed in systemic lupus erythematosus (SLE). Oxidative modification of LDL is associated with atherosclerotic plaque formation.

OBJECTIVES

We hypothesized that anti-oxidized LDL (oxLDL) and anti-phospholipid (APL) in SLE sera would segregate with specific antibody subsets, and that anti-oxLDL antibodies will linger in circulation over an extended period.

PATIENTS AND METHODS

Sixty-seven SLE and control subjects and two SLE subjects with sera collected longitudinally for 13 years were tested for anti-oxLDL and IgG/IgM/IgA APL antibodies.

RESULTS

Anti-oxLDL ELISA values above 57.48 Activity Units (AcU) (means of normals + 3 standard deviations) and anti-IgG/IgM/IgA APL above 10 phospholipid units (PU) were considered positive. Average anti-oxLDL was 67.7 ± 50.5 AcU in SLE compared to 23.9 ± 11.19 AcU in normals (P = 0.018). Ten out of ten subjects with anti-Ro60/anti-La/anti-Ro52 antibodies had highly significant (P < 0.0001) anti-oxLDL (127.29 ± 45.67 AcU) and IgG APL (18.66 ± 7.4 PU) (P < 0.02). Subjects with anti-RNP were positive for anti-oxLDL (P < 0.002), but subjects with anti-Ro60/anti-Ro52 and subjects negative for extractable nuclear antigen (ENA) antibody were not positive for anti-oxLDL. Anti-oxLDL/anti-IgG APL remained significantly elevated in two patients studied longitudinally. Interestingly, one developed anti-oxLDL/anti-APL antibodies several years before anti-Ro60 development.

CONCLUSIONS

Presence of antibodies against Ro RNP and La, and RNP is highly associated with developing anti-oxLDL and APL antibodies in SLE. It will be clinically important to see if cardiovascular events occur in these SLE subsets having elevated anti-oxLDL and APL antibodies. Emergence of anti-oxLDL/IgG APL before anti-Ro60 over time in a patient indicates that these antibodies could not be cross-reactive in nature, at least in this particular patient.

Identification of Stages of Erythroid Differentiation in Bone Marrow and Erythrocyte Subpopulations in Blood Circulation that Are Preferentially Lost in Autoimmune Hemolytic Anemia in Mouse

Repeated weekly injections of rat erythrocytes produced autoimmune hemolytic anemia (AIHA) in C57BL/6 mice after 5–6 weeks. Using the double in vivo biotinylation (DIB) technique, recently developed in our laboratory, turnover of erythrocyte cohorts of different age groups during AIHA was monitored. Results indicate a significant decline in the proportion of reticulocytes, young and intermediate age groups of erythrocytes, but a significant increase in the proportion of old erythrocytes in blood circulation. Binding of the autoantibody was relatively higher to the young erythrocytes and higher levels of intracellular reactive oxygen species (ROS) were also seen in these cells. Erythropoietic activity in the bone marrows and the spleen of AIHA induced mice was examined by monitoring the relative proportion of erythroid cells at various stages of differentiation in these organs. Cells at different stages of differentiation were enumerated flow cytometrically by double staining with anti-Ter119 and anti-transferrin receptor (CD71) monoclonal antibodies. Erythroid cells in bone marrow declined significantly in AIHA induced mice, erythroblast C being most affected (50% decline). Erythroblast C also recorded high intracellular ROS level along with increased levels of membrane-bound autoantibody. No such decline was observed in spleen. A model of AIHA has been proposed indicating that binding of autoantibodies may not be a sufficient condition for destruction of erythroid cells in bone marrow and in blood circulation. Last stage of erythropoietic differentiation in bone marrow and early stages of erythrocytes in blood circulation are specifically susceptible to removal in AIHA.

Lipid peroxidation as risk factor for endothelial dysfunction in antiphospholipid syndrome patients

The aim of this study was to evaluate oxidative stress markers and it relations to endothelial damage as risk factor for thrombosis in patients with primary (PAPS) and secondary (SAPS) antiphospholipid syndrome (APS) in correlation to traditional risk factors. Flow-mediated (FMD) and nitroglycerine (NMD)-induced dilation of the brachial artery were studied in 140 APS patients (90 PAPS, 50 SAPS) and 40 controls matched by age, sex, and conventional risk factors for atherosclerosis. Markers of oxidative stress, lipid hydroperoxydes (LOOH), advanced oxidation protein products (AOPP), total sulfhydryl groups (tSHG), and paraoxonase 1 activity (PON1) were determined by spectrophotometric method. Oxidative stress dominates in APS patients. LOOH and AOPP correlate to lipid fractions (p < 0.05), unlike PON1, tSHG that correlated to antiphospholipid antibody positivity (p < 0.05). FMD was lower in APS patients comparing to controls (p < 0.001). Cholesterol is independent variable for FMD impairment in control group (p = 0.011); LOOH in PAPS (p = 0.004); LOOH, aCL, and triglycerides in SAPS patients (p = 0.009, p = 0.049, and p = 0.012, respectively). Combined predictive of aCL and LOOH is better for FMD impairment than LOOH alone in both PAPS and SAPS patients (AUC 0.727, p = 0.001, 95 % CI 0.616-0.837 and AUC 0.824, p˂0.001, 95 % CI 0.690-0.957, respectively). Lipid peroxidation is independent predictor for endothelial dysfunction in APS patients. We demonstrated synergistic effect of aCL and LOOH as risk for endothelial impairment in both PAPS and SAPS patients.

Lack of flow mediated dilation and enhanced angiotensin II-induced constriction in skeletal muscle arterioles of lupus-prone autoimmune mice

Systemic lupus erythematosus (SLE) is associated with disturbances in the microcirculation of various tissues, yet the nature of arteriolar dysfunction has not been characterized. Thus, changes in diameter of isolated, pressurized skeletal muscle arterioles of mice with systemic autoimmune disease (lupus prone, MRL/lpr four-month old female) and control (MRL) mice were investigated by video-microscopy. Arteriolar responses to changes in intraluminal pressure, flow, and to vasoactive agents with known mechanisms of action were compared. The active and passive (in Ca2+ free solution) diameter of MRL/lpr arterioles were not significantly different compared to MRL and morphometric changes were not apparent. Compared to MRL mice the endothelium-dependent dilations to increase in flow, acetylcholine and bradykinin were markedly reduced in arterioles of MRL/lpr mice. Endothelium-independent dilations to sodium-nitroprusside and adenosine were similar in MRL and MRL/lpr arterioles. Furthermore, angiotensin II elicited greater constrictions in MRL/lpr arterioles, whereas serotonin-induced constrictions were similar in both groups. Thus, in arterioles of MRL/lpr mice endothelium-dependent dilator mechanisms are impaired and constriction to angiotensin II is enhanced, suggesting specific alterations in the vasomotor function of microvessels that are likely contribute to the disturbance of skeletal muscle blood flow observed in systemic lupus erythematosus.

Altered renal immune complexes deposition in female BWF1 lupus mice following Plasmodium chabaudi infection

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease that has a mysterious relationship with malaria infection. The current study was designated to compare between the effect of the live and the gamma irradiated Plasmodium chabaudi infection on BWF1 lupus murine model. A total of 30 female BWF1 mice were randomly divided into three groups (10 mice/group) as follows: group (I) lupus group (lupus non infected); group (II) live malaria infected group (lupus + live malaria infection); and group (III) irradiated malaria-infected group (lupus + gamma irradiated malaria infection). Live P. chabaudi infection was accompanied with a decrease in survival rate and food consumption in comparison to the control group of mice while gamma irradiated P. chabaudi -infection was unable to do this effect. Additionally, live P. chabaudi infection was accompanied with an increased level of proteinuria and increased rate of immune complexes deposition in kidney. Moreover, infection with live, but not gamma-irradiated P. chabaudi was accompanied with an increase in nitric oxide (NO), hydrogen peroxide (H₂O₂), and malondialdehyde (MDA) levels in plasma of lupus mice. The levels of both total cholesterol and triglycerides in plasma of lupus mice after live P. chabaudi infection were obviously decreased in comparison to the control group. On the other hand, gamma-irradiated P. chabaudi infection resembled the control group. Our data revealed that infection of lupus mice with live but not gamma-irradiated P. chabaudi has several histological and biochemical effects.

iNOS null MRL+/+ mice show attenuation of trichloroethene-mediated autoimmunity: contribution of reactive nitrogen species and lipid-derived reactive aldehydes

Earlier studies from our laboratory in MRL+/+ mice suggest that free radicals, especially overproduction of reactive nitrogen species (RNS) and lipid-derived reactive aldehydes (LDRAs), are associated with trichloroethene (TCE)-mediated autoimmune response. The current study was undertaken to further assess the contribution of RNS and LDRAs in TCE-mediated autoimmunity by using iNOS-null MRL+/+ mice. iNOS-null MRL+/+ mice were obtained by backcrossing iNOS-null mice (B6.129P2-Nos2(tm1Lau)/J) to MRL +/+ mice. Female MRL+/+ and iNOS-null MRL+/+ mice were given TCE (10 mmol/kg, i.p., every 4(th) day) for 6 weeks; their respective controls received corn oil only. TCE exposure led to significantly increased iNOS mRNA in livers, iNOS protein in livers and sera, increased nitrotyrosine (NT) formation in both livers and sera, induction of MDA-/HNE-protein adducts in livers and their respective antibodies in sera along with significant increases in serum antinuclear antibodies (ANA) and anti-dsDNA in MRL+/+ mice. Even though in iNOS-null MRL+/+ mice, the iNOS and NT levels were negligible in both TCE-treated and untreated groups, TCE treatment still led to significant increases in MDA-/HNE-protein adducts and their respective antibodies along with increases in serum ANA and anti-dsDNA compared to controls. Most remarkably, the increases in serum ANA and anti-dsDNA induced by TCE in the iNOS-null MRL+/+ mice were significantly less pronounced compared to that in MRL+/+ mice. Our results provide further evidence that both RNS and LDRAs contribute to TCE-induced autoimmunity in MRL+/+ mice, and iNOS deficiency attenuates this autoimmune response.

Lipid peroxidation, proteins modifications, anti-oxidant enzymes activities and selenium deficiency in the plasma of hashitoxicosis patients

OBJECTIVES

The aim of this study was to explore the oxidative stress profile in hashitoxicosis (HTX) and to compare it with that of healthy subjects.

PATIENTS AND METHODS

Spectrophotometric methods were used to evaluate the oxidative stress markers. The selenium level was investigated by atomic absorption.

RESULTS

High levels of thiobarbituric acid reactive species (TBARS) and conjugated dienes were found in HTX patients (p = 0.034 and p = 0.043, respectively) compared with healthy controls. For antioxidant enzymes, superoxide dismutase (SOD) and catalase activities increased, whereas that of glutathione peroxidase (GPx) decreased (p = 0.000, p = 0.014, p = 0.000, respectively) compared with controls. A reduction in the level of selenium (p = 0.029) and thiol groups (p = 0.008) were shown in patients; however, levels of carbonyl group and malondialdehyde (MDA) protein adducts decreased (p = 0.000) compared with controls. Positive correlation was shown between levels of free thyroxine (FT4) and TBARS (r = 0.711, p = 0.048) and between FT4 level and SOD activity (r = 0.713, p = 0.047). Conversely, GPx activity presented a negative correlation with FT4 and free triiodothyronine (FT3) levels (r = -0.934, p = 0.001; r = -0.993, p = 0.000, respectively). In addition, GPx activity showed positive correlation with selenium level (r = 0.981, p = 0.019) and the FT3 level correlated negatively with the level of thiol groups (r = -0.892, p = 0.017).

CONCLUSIONS

This study shows the presence of an oxidative stress and selenium deficiency in HTX patients and suggests that the hyperthyroid state is strongly implicated in the establishment of this disturbed oxidative profile.

Significantly reduced lymphadenopathy, salivary gland infiltrates and proteinuria in MRL-lpr/lpr mice treated with ultrasoluble curcumin/turmeric: increased survival with curcumin treatment

Objectives

Commercial curcumin (CU), derived from food spice turmeric (TU), has been widely studied as a potential therapeutic for a variety of oncological and inflammatory conditions. Lack of solubility/bioavailability has hindered curcumin's therapeutic efficacy in human diseases. We have solubilised curcumin in water applying heat/pressure, obtaining up to 35-fold increase in solubility (ultrasoluble curcumin (UsC)). We hypothesised that UsC or ultrasoluble turmeric (UsT) will ameliorate systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS)-like disease in MRL-lpr/lpr mice.

Methods

Eighteen female MRL-lpr/lpr (6 weeks old) and 18 female MRL-MpJ mice (6 weeks old) were used. Female MRL-lpr/lpr mice develop lupus-like disease at the 10th week and die at an average age of 17 weeks. MRL-MpJ mice develop lupus-like disease around 47 weeks and typically die at 73 weeks. Six mice of each strain received autoclaved water only (lpr-water or MpJ-water group), UsC (lpr-CU or MpJ-CU group) or UsT (lpr-TU or MpJ-TU group) in the water bottle.

Results

UsC or UsT ameliorates SLE in the MRL-lpr/lpr mice by significantly reducing lymphoproliferation, proteinuria, lesions (tail) and autoantibodies. lpr-CU group had a 20% survival advantage over lpr-water group. However, lpr-TU group lived an average of 16 days shorter than lpr-water group due to complications unrelated to lupus-like illness. CU/TU treatment inhibited lymphadenopathy significantly compared with lpr-water group (p=0.03 and p=0.02, respectively) by induction of apoptosis. Average lymph node weights were 2606±1147, 742±331 and 385±68 mg, respectively, for lpr-water, lpr-CU and lpr-TU mice. Transferase dUTP nick end labelling assay showed that lymphocytes in lymph nodes of lpr-CU and lpr-TU mice underwent apoptosis. Significantly reduced cellular infiltration of the salivary glands in the lpr-TU group compared with the lpr-water group, and a trend towards reduced kidney damage was observed in the lpr-CU and lpr-TU groups.

Conclusions

These studies show that UsC/UsT could prove useful as a therapeutic intervention in SLE/SS.

Substitution effects of a carbonated hydroxyapatite biomaterial against intoxication chloride nickel-exposed rats

AIMS

This study aimed to investigate the potential effects of a synthetic apatite (carbonated hydroxyapatite) on the detoxification of a group of male "Wistar" rats exposed to nickel chloride.

METHODS

Toxicity was evaluated by rats' bioassay of nickel chloride. Wistar rats received this metal daily by gavage for seven days (4 mg/ml nickel chloride/200 g body weight, BW). To detoxify this organism, a subcutaneous implantation of the apatite is made.

RESULTS

The results revealed that exposure to nickel induced oxidative stress, disorders in the balances of ferric phosphocalcic, renal failures, liver toxicity and significant increase in nickel rates in the bones of intoxicated rats. The application of the carbonated hydroxyapatite presented in this study restored those disorders back to normal. The synthetic apatite protected the rats against the toxic effects of nickel by lowering the levels of lipid peroxidation markers and improving the activities of defense enzymes. It also amended ferric and phosphocalcic equilibriums, protected liver and kidney functions and reduced the nickel rate in the bones of the rats. Overall, the results provided strong support for the protective role of carbonated hydroxyapatite in the detoxification of rats exposed to nickel. Those beneficial effects were further confirmed by physico-chemical characterization (X-ray diffraction and infrared spectroscopy), which revealed its property of anionic and cationic substitution, thus supporting its promising candidacy for future biomedical application.

CONCLUSION

The hydroxyapatite is an effective biomaterial to solve health problems, particularly detoxification against metals (nickel).

Modulation of PPARγ provides new insights in a stress induced premature senescence model

Peroxisome proliferator-activated receptor gamma (PPARγ) may be involved in a key mechanism of the skin aging process, influencing several aspects related to the age-related degeneration of skin cells, including antioxidant unbalance. Therefore, we investigated whether the up-modulation of this nuclear receptor exerts a protective effect in a stress-induced premature senescence (SIPS) model based on a single exposure of human dermal fibroblasts to 8-methoxypsoralen plus + ultraviolet-A-irradiation (PUVA). Among possible PPARγ modulators, we selected 2,4,6-octatrienoic acid (Octa), a member of the parrodiene family, previously reported to promote melanogenesis and antioxidant defense in normal human melanocytes through a mechanism involving PPARγ activation. Exposure to PUVA induced an early and significant decrease in PPARγ expression and activity. PPARγ up-modulation counteracted the antioxidant imbalance induced by PUVA and reduced the expression of stress response genes with a synergistic increase of different components of the cell antioxidant network, such as catalase and reduced glutathione. PUVA-treated fibroblasts grown in the presence of Octa are partially but significantly rescued from the features of the cellular senescence-like phenotype, such as cytoplasmic enlargement, the expression of senescence-associated-β-galactosidase, matrix-metalloproteinase-1, and cell cycle proteins. Moreover, the alterations in the cell membrane lipids, such as the decrease in the polyunsaturated fatty acid content of phospholipids and the increase in cholesterol levels, which are typical features of cell aging, were prevented. Our data suggest that PPARγ is one of the targets of PUVA-SIPS and that its pharmacological up-modulation may represent a novel therapeutic approach for the photooxidative skin damage.

Mitochondrial DNA damage is associated with damage accrual and disease duration in patients with systemic lupus erythematosus

OBJECTIVE

To determine the extent of mitochondrial DNA (mtDNA) damage in systemic lupus erythematosus (SLE) patients compared to healthy subjects and to determine the factors associated with mtDNA damage among SLE patients.

METHODS

A cross-sectional study was performed in 86 SLE patients (per American College of Rheumatology classification criteria) and 86 healthy individuals matched for age and gender. Peripheral blood mononuclear cells (PBMCs) were collected from subjects to assess the relative amounts of mtDNA damage. Quantitative polymerase chain reaction assay was used to measure the frequency of mtDNA lesions and mtDNA abundance. Socioeconomic-demographic features, clinical manifestations, pharmacologic treatment, disease activity, and damage accrual were determined. Statistical analyses were performed using t test, pairwise correlation, and Pearson's chi-square test (or Fisher's exact test) as appropriate.

RESULTS

Among SLE patients, 93.0% were women. The mean (SD) age was 38.0 (10.4) years and the mean (SD) disease duration was 8.7 (7.5) years. SLE patients exhibited increased levels of mtDNA damage as shown by higher levels of mtDNA lesions and decreased mtDNA abundance as compared to healthy individuals. There was a negative correlation between disease damage and mtDNA abundance and a positive correlation between mtDNA lesions and disease duration. No association was found between disease activity and mtDNA damage.

CONCLUSION

PBMCs from SLE patients exhibited more mtDNA damage compared to healthy subjects. Higher levels of mtDNA damage were observed among SLE patients with major organ involvement and damage accrual. These results suggest that mtDNA damage have a potential role in the pathogenesis of SLE.

Altered glutamate cysteine ligase activity in peripheral blood mononuclear cells from patients with systemic lupus erythematosus

Reductions in glutathione (GSH) levels have been shown to be associated with aging and the pathogenesis of a variety of diseases, including systemic lupus erythematosus (SLE). Glutamate cysteine ligase (GCL) catalyzes the first and rate-limiting step of GSH synthesis. In order to appraise the correlation between oxidative stress and the severity and activity of SLE, GSH, oxidized GSH (GSSG) and thioredoxin (TRX) concentrations and the enzymatic activity levels of GCL in peripheral blood mononuclear cells (PBMCs) from patients with SLE and healthy controls were studied. In patients with SLE, the levels of GCL activity and GSH decreased, while TRX and GSSG levels increased when compared with those in the healthy controls. GSH concentrations and GCL activity levels negatively correlated with the SLE disease activity index and erythrocyte sedimentation rate. Furthermore, patients with SLE and nephritis had lower levels of GSH and GCL activity and higher levels of TRX and GSSG compared with those in SLE patients without nephritis. Therefore, the results of the present study indicate that insufficient levels of GSH and GCL activity in PBMCs may contribute to the pathogenesis of SLE.

Association between serum trace element concentrations and the disease activity of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease with a complex, incompletely understood, etiology. Several genetic and environmental factors are suspected to be involved in its aetiology. Oxidative stress may be implicated in the pathogenesis of SLE and may be affected by trace element status. Zinc (Zn), copper (Cu) and selenium (Se) are essential components of several anti-oxidative enzymes and are also involved in several immune functions. The current study aimed to assess the relationship between serum concentrations of these trace elements and the clinical disease activity of SLE assessed using the SLE disease activity index (SLEDAI). Serum concentrations of albumin (Alb) (p = 0.001), Se (p = 0.001), Zn (p = 0.001) and the Zn to Cu ratio (Zn/Cu R) (p = 0.001) were lower in patients with SLE than the age- and sex-matched healthy controls. However, only Alb (p = 0.001) and Cu (p = 0.03) were negatively correlated with disease activity, which was supported by regression analysis. In summary, lower serum values of Alb, Zn, Se and Zn/Cu R were found in SLE patients compared with healthy controls; however, in addition to serum Alb concentrations, serum Cu concentrations were also negatively correlated with lupus disease activity.

Oxidative stress markers in intestinal mucosa of Tunisian inflammatory bowel disease patients

BACKGROUND / AIMS: Inflammatory bowel diseases (IBDs), Crohn's disease (CrD) and ulcerative colitis (UC), are chronic gastrointestinal inflammatory disorders. The precise etiology of IBD remains unclear, and it is thought that interactions among various factors, including, genetic factors, the host immune system and environmental factors, cause disruption of intestinal homeostasis, leading to dysregulated inflammatory responses of the gut. As inflammation is intimately related to formation of reactive intermediates, including, reactive oxygen species, oxidative stress has been proposed as a mechanism underlying the pathophysiology of IBD. The purpose of this study is to examine the lipid peroxidation, protein oxidation and anti-oxidative profile in Tunisian IBD.

MATERIALS AND METHODS

Malondialdehyde (MDA), conjugated dienes (CD), protein thiol levels, as well as the catalase (CAT) activity were evaluated in intestinal biopsies of 17 patients affected by IBD (12 CrD and 5 UC) and 12 healthy control individuals.

RESULTS

Oxidative stress was confirmed in these two types of disease biopsies as compared to controls. MDA and CD levels were significantly increased in both UC and CrD patients' biopsies as compared to controls' biopsies ( P < 0.001). CAT activity was similar in UC and CrD biopsies' and was not significantly increased in IBD patients' biopsies compared with controls' biopsies ( P > 0.05). Anon-significant decrease in thiol (SH) level was observed in both UC and CrD patients' biopsies compared with controls' biopsies ( P > 0.05).

CONCLUSION

Increased levels of MDA and CD in IBD patients' biopsies underline the implication of oxidative stress in the physiopathology of IBD.

Interaction between glutathione and apoptosis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by imbalance redox state and increased apoptosis. The activation, proliferation and cell death of lymphocytes are dependent on intracellular levels of glutathione and controlled production of reactive oxygen species (ROS). Changes in the intracellular redox environment of cells, through oxygen-derived free radical production known as oxidative stress, have been reported to be critical for cellular immune dysfunction, activation of apoptotic enzymes and apoptosis. The shift in the cellular GSH-to-GSSG redox balance in favor of the oxidized species, GSSG, constitutes an important signal that can decide the fate of the abnormal apoptosis in the disease. The current review will focus on four main areas: (1) general description of oxidative stress markers in SLE, (2) alteration of redox state and complication of disease, (3) role of redox mechanisms in the initiation and execution phases of apoptosis, and (4) intracellular glutathione and its checkpoints with lymphocyte apoptosis which represent novel targets for pharmacological intervention in SLE.

Protein kinase Cδ oxidation contributes to ERK inactivation in lupus T cells

OBJECTIVE

CD4+ T cells from patients with active lupus have impaired ERK pathway signaling that decreases DNA methyltransferase expression, resulting in DNA demethylation, overexpression of immune genes, and autoimmunity. The ERK pathway defect is due to impaired phosphorylation of T(505) in the protein kinase Cδ (PKCδ) activation loop. However, the mechanisms that prevent PKCδ T(505) phosphorylation in lupus T cells are unknown. Others have reported that oxidative modifications, and nitration in particular, of T cells as well as serum proteins correlate with lupus disease activity. We undertook this study to test our hypothesis that nitration inactivates PKCδ, contributing to impaired ERK pathway signaling in lupus T cells.

METHODS

CD4+ T cells were purified from lupus patients and controls and then stimulated with phorbol myristate acetate (PMA). Signaling protein levels, nitration, and phosphorylation were quantitated by immunoprecipitation and immunoblotting of T cell lysates. Transfections were performed by electroporation.

RESULTS

Treating CD4+ T cells with peroxynitrite nitrated PKCδ, preventing PKCδ T(505) phosphorylation and inhibiting ERK pathway signaling similar to that observed in lupus T cells. Patients with active lupus had higher nitrated T cell PKCδ levels than did controls, which correlated directly with disease activity, and antinitrotyrosine immunoprecipitations demonstrated that nitrated PKCδ, but not unmodified PKCδ, was refractory to PMA-stimulated T(505) phosphorylation, similar to PKCδ in peroxynitrite-treated cells.

CONCLUSION

Oxidative stress causes PKCδ nitration, which prevents its phosphorylation and contributes to the decreased ERK signaling in lupus T cells. These results identify PKCδ as a link between oxidative stress and the T cell epigenetic modifications in lupus.

Catalase and lipid peroxidation values in serum of Tunisian patients with pemphigus vulgaris and foliaceus

Pemphigus is an autoimmune disorder resulting from the interaction between autoantibodies and desmoglein. Oxidative stress seems to be responsible for the onset/aggravation of many human diseases. Actually, it is considered as one of the several factors for the etiopathogenesis of pemphigus. The present study aims to evaluate the oxidative state in the sera of pemphigus vulgaris and pemphigus foliaceus patients by assessing lipid peroxidation, proteins oxidation, and antioxidant enzyme activity. This study included 36 pemphigus vulgaris and 42 pemphigus foliaceus patients as well as a group of controls consisting of 78 healthy volunteers. Malondialdehyde levels (p < 0.001) and catalase activity (p < 0.001) are higher in both groups of patients than in the control group. The two groups of patients showed a nonsignificant decrease in the thiol groups compared with the healthy one. A nonsignificant difference was shown between pemphigus vulgaris and pemphigus foliaceus patients, except for the catalase which shows an increase in the pemphigus vulgaris group. We have also found significant correlations between serum oxidative stress marker levels and serum anti-desmoglein antibody levels in the two pemphigus groups. These findings underline the implication of oxidative stress in the physiopathology of pemphigus by the increase in the autoantibodies' reactivity.

Differential oxidative modification of proteins in MRL+/+ and MRL/lpr mice: Increased formation of lipid peroxidation-derived aldehyde-protein adducts may contribute to accelerated onset of autoimmune response

Even though reactive oxygen species (ROS) have been implicated in SLE pathogenesis, the contributory role of ROS, especially the consequences of oxidative modification of proteins by lipid peroxidation-derived aldehydes (LPDAs) such as malondialdehyde (MDA) and 4-hydroxynonenal (HNE) in eliciting an autoimmune response and disease pathogenesis remains largely unexplored. MRL/lpr mice, a widely used model for SLE, spontaneously develop a condition similar to human SLE, whereas MRL+/+ mice with the same MRL background, show much slower onset of SLE. To assess if the differences in the onset of SLE in the two substrains could partly be due to differential expression of LPDAs and to provide evidence for the role of LPDA-modified proteins in SLE pathogenesis, we determined the serum levels of MDA-/HNE-protein adducts, anti-MDA-/HNE-protein adduct antibodies, MDA-/HNE-protein adduct specific immune complexes, and various autoantibodies in 6-, 12- and 18-week old mice of both substrains. The results show age-related increases in the formation of MDA-/HNE-protein adducts, their corresponding antibodies and MDA-/HNE-specific immune complexes, but MRL/lpr mice showed greater and more accelerated response. Interestingly, a highly positive correlation between increased anti-MDA-/HNE-protein adduct antibodies and autoantibodies was observed. More importantly, we further observed that HNE-MSA caused significant inhibition in antinuclear antibodies (ANA) binding to nuclear antigens. These findings suggest that LPDA-modified proteins could be important sources of autoantibodies and CICs in these mice, and thus contribute to autoimmune disease pathogenesis. The observed differential responses to LPDAs in MRL/lpr and MRL+/+ mice may, in part, be responsible for accelerated and delayed onset of the disease, respectively.

Altered redox state and apoptosis in the pathogenesis of systemic lupus erythematosus

An altered redox status and increased lymphocyte apoptosis have been implicated in the development of systemic lupus erythematosus (SLE). In this study, we evaluated the relationship between glutathione (GSH) depletion, reactive oxygen species (ROS) and, the progression of apoptosis and their association with SLE severity. Significant low levels of intracellular glutathione, total thiol and altered redox state (GSH/GSSG) were found in SLE patients, in which lymphocyte apoptosis and activated caspase-3 expression in the lymphocytes were remarkably increased. The severity of disease was positively allied with the increased levels of lymphocyte apoptosis and caspase-3, but negatively with the decreased levels of total thiol, depleted intracellular glutathione and altered redox state (GSH/GSSG). The lymphocyte apoptosis and activated caspase-3 expression were negatively associated with intracellular levels of GSH and redox state and positively associated with the elevated levels of multiple oxidative stress markers; ROS and lipid peroxidation measured as malondialdehyde (MDA). These results suggest that GSH depletion and elevated oxidative stress trigger apoptosis and may be coupled with the severity of the disease.

Biomarkers of oxidative stress in epidermis of Tunisian pemphigus foliaceus patients

BACKGROUND

Reactive oxygen species play a key role in the development of many dermatological disorders.

OBJECTIVE

The purpose of this study is to examine the lipid peroxidation, protein oxidation and antioxidative profile in Tunisian pemphigus foliaceus (PF) patients.

METHODS

Malondialdehyde (MDA), conjugated dienes (CD), protein thiol levels, catalase (CAT) and superoxide dismutase (SOD) activities were evaluated in skin biopsies of 13 patients compared to biopsies of 7 healthy controls.

RESULTS

Oxidative stress was confirmed in these three types of patient biopsies as compared to controls. Thus, MDA, CD levels and catalase CAT and SOD activities were significantly increased in lesional, perilesional and normal biopsies of PF patients than in those of control subjects. Protein oxidative was confirmed by lower levels of protein thiols in lesional, perilesional and normal biopsies than in control's biopsies. Otherwise, in patients, a significant rise of these biomarkers was observed in lesional and perilesional biopsies compared with normal biopsies.

CONCLUSION

This study shows that oxidative stress could be involved in the pathogenesis of PF by the spread of skin lesions and/or by the increase in auto-antibodies' reactivity.

Association of catalase gene polymorphisms with catalase activity and susceptibility to systemic lupus erythematosus in the Suez Canal area, Egypt

The present study evaluated the relationship of genetic variants in both promoter (−262 C/T) and in exonic (389 C/T) regions of the catalase (CAT) gene to CAT activity and risk of systemic lupus erythematosus (SLE) in Suez Canal-area patients. CAT gene polymorphisms were assessed by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). CAT activity was measured by using a spectrophotometer. We compared the frequencies of CAT 389 C/T and −262 C/T polymorphic variants between SLE patients ( n = 103) and healthy controls ( n = 103). CAT 389 C/T is associated with SLE susceptibility, with the T allele being significantly more frequent among SLE patients than healthy controls. There was no association, however, between CAT activity and genotypes of 389 C/T. We did not observe significant differences in the prevalence of CAT −262 C/T polymorphic variants in SLE patients and controls, however, we found that patients with the CAT −262 CT and TT genotypes had low CAT activity, and these genotypes showed a significant association with thrombocytopaenia, leukopaenia and the presence of anti-snRNP in SLE patients. In conclusion, the present study supports the notion of in vivo oxidative stress in SLE as indicated by the decrease in CAT activity. The allelic variations in the CAT gene −262 are more likely to affect the expression or the function of the enzyme. Since CAT may be pathogenetically linked to SLE, and owing to its free-radical origin, it appears reasonable to target lipid peroxidation by dietary and/or pharmacological antioxidants.

Protein adducts of malondialdehyde and 4-hydroxynonenal contribute to trichloroethene-mediated autoimmunity via activating Th17 cells: dose- and time-response studies in female MRL+/+ mice

Trichloroethene (TCE), a common occupational and environmental toxicant, is known to induce autoimmunity. Previous studies in our laboratory showed increased oxidative stress in TCE-mediated autoimmunity. To further establish the role of oxidative stress and to investigate the mechanisms of TCE-mediated autoimmunity, dose- and time-response studies were conducted in MRL+/+ mice by treating them with TCE via drinking water at doses of 0.5, 1.0 or 2.0mg/ml for 12, 24 or 36 weeks. TCE exposure led to dose-related increases in malondialdehyde (MDA)-/hydroxynonenal (HNE)-protein adducts and their corresponding antibodies in the sera and decreases in GSH and GSH/GSSG ratio in the kidneys at 24 and 36 weeks, with greater changes at 36 weeks. The increases in these protein adducts and decreases in GSH/GSSG ratio were associated with significant elevation in serum anti-nuclear- and anti-ssDNA-antibodies, suggesting an association between TCE-induced oxidative stress and autoimmune response. Interestingly, splenocytes from mice treated with TCE for 24 weeks secreted significantly higher levels of IL-17 and IL-21 than did splenocytes from controls after stimulation with MDA-mouse serum albumin (MSA) or HNE-MSA adducts. The increased release of these cytokines showed a dose-related response and was more pronounced in mice treated with TCE for 36 weeks. These studies provide evidence that MDA- and or HNE-protein adducts contribute to TCE-mediated autoimmunity, which may be via activation of Th17 cells.

Putative sequences on Ro60 three-dimensional structure accessible for 4-hydroxy-2-nonenal (HNE) modification compared to in vitro HNE modification of Ro60 sequences

We have previously reported accelerated acquisition of new autoreactivity upon immunization with 4-hydroxy-2-nonenal (HNE)-modified Ro60, as well as differential induction of lupus or Sjögren's syndrome by immunization with Ro60 containing varying amounts of HNE. Since the number of HNE molecules on Ro60 appears to be important, we hypothesized that specific sequences on Ro60 are targets for HNE-modification. Using surface plasmon resonance (SPR) we have also shown intramolecular protein-protein interaction between Ro60 and Ro multiple antigenic peptides (MAPs). We also hypothesized that intramolecular protein-protein interaction would be abolished by HNE-modification. To test this hypotheses we investigated (a) the epitopes of Ro60, using 19 Ro MAPs in an in vitro assay (involving HNE-modification of MAPs following immobilization on ELISA plates) to identify targets of HNE modification on Ro60 and (b) the protein-protein interaction between unmodified Ro60 MAPs, immobilized on the sensor surface of BIAcore, and unmodified Ro60 or HNE-modified Ro60 using SPR. New data obtained with SPR strengthens our earlier observation that immunization with HNE-Ro60 induces a stronger response. Unmodified Ro60 bound to several Ro60 MAPs through protein-protein interaction analyzed using SPR. This interaction was totally abrogated using HNE-modified Ro60 suggesting that sequences on Ro had become modified with HNE. When 19 Ro60 MAPs were modified in vitro with HNE, it was found that 10/19 MAPs significantly bound HNE covalently (p<0.001 compared to MAPs binding HNE poorly). The amino acid sequences 126-137, 166-272 and 401-495 on Ro60 were strongly HNE modified. Using computational model system based on the recently published crystal structure for Ro60 enabled us to identify regions on the Ro60 molecule represented by the HNE-modified Ro MAPs, which are part of the exposed tertiary structure of the Ro60 protein.

High ACSL5 transcript levels associate with systemic lupus erythematosus and apoptosis in Jurkat T lymphocytes and peripheral blood cells

BACKGROUND

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease in which increased apoptosis and decreased apoptotic cells removal has been described as most relevant in the pathogenesis. Long-chain acyl-coenzyme A synthetases (ACSLs) have been involved in the immunological dysfunction of mouse models of lupus-like autoimmunity and apoptosis in different in vitro cell systems. The aim of this work was to assess among the ACSL isoforms the involvement of ACSL2, ACSL4 and ACSL5 in SLE pathogenesis.

FINDINGS

With this end, we determined the ACSL2, ACSL4 and ACSL5 transcript levels in peripheral blood mononuclear cells (PBMCs) of 45 SLE patients and 49 healthy controls by quantitative real time-PCR (q-PCR). We found that patients with SLE had higher ACSL5 transcript levels than healthy controls [median (range), healthy controls = 16.5 (12.3-18.0) vs. SLE = 26.5 (17.8-41.7), P = 3.9×10 E-5] but no differences were found for ACSL2 and ACSL4. In in vitro experiments, ACSL5 mRNA expression was greatly increased when inducing apoptosis in Jurkat T cells and PBMCs by Phorbol-Myristate-Acetate plus Ionomycin (PMA+Io). On the other hand, short interference RNA (siRNA)-mediated silencing of ACSL5 decreased induced apoptosis in Jurkat T cells up to the control levels as well as decreased mRNA expression of FAS, FASLG and TNF.

CONCLUSIONS

These findings indicate that ACSL5 may play a role in the apoptosis that takes place in SLE. Our results point to ACSL5 as a potential novel functional marker of pathogenesis and a possible therapeutic target in SLE.