Inflammation, infection, cancer and all that…the role of paraoxonases

FOXA1 Suppresses Endoplasmic Reticulum Stress, Oxidative Stress, and Neuronal Apoptosis in Parkinson's Disease by Activating PON2 Transcription

Endoplasmic reticulum (ER) stress and oxidative stress (OS) are often related states in pathological conditions including Parkinson's disease (PD). This study investigates the role of anti-oxidant protein paraoxonase 2 (PON2) in ER stress and OS in PD, along with its regulatory molecule. PD was induced in C57BL/6 mice using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) treatment and in SH-SY5Y cells using 1-methyl-4-phenylpyridinium. PON2 was found to be poorly expressed in the substantia nigra pars compacta (SNc) of PD mice, and its overexpression improved motor coordination of mice. Through the evaluation of tyrosine hydroxylase, dopamine transporter, reactive oxygen species (ROS), and C/EBP homologous protein (CHOP) levels and neuronal loss in mice, as well as the examination of CHOP, glucose-regulated protein 94 (GRP94), GRP78, caspase-12, sarco/endoplasmic reticulum calcium ATPase 2, malondialdehyde, and superoxide dismutase levels in SH-SY5Y cells, we observed that PON2 overexpression mitigated ER stress, OS, and neuronal apoptosis both in vivo and in vitro. Forkhead box A1 (FOXA1) was identified as a transcription factor binding to the PON2 promoter to activate its transcription. Upregulation of FOXA1 similarly protected against neuronal loss by alleviating ER stress and OS, while the protective roles were abrogated by additional PON2 silencing. In conclusion, this study demonstrates that FOXA1-mediated transcription of PON2 alleviates ER stress and OS, ultimately reducing neuronal apoptosis in PD.

Contribution of the Paraoxonase-2 Enzyme to Cancer Cell Metabolism and Phenotypes

Paraoxonase-2 (PON2) is a ubiquitously expressed intracellular protein that is localized in the perinuclear region, the endoplasmic reticulum (ER), and mitochondria, and is also associated with the plasma membrane. PON2 functions as an antioxidant enzyme by reducing the levels of reactive oxygen species (ROS) in the mitochondria and ER through different mechanisms, thus having an anti-apoptotic effect and preventing the formation of atherosclerotic lesions. While the antiatherogenic role played by this enzyme has been extensively explored within endothelial cells in association with vascular disorders, in the last decade, great efforts have been made to clarify its potential involvement in both blood and solid tumors, where PON2 was reported to be overexpressed. This review aims to deeply and carefully examine the contribution of this enzyme to different aspects of tumor cells by promoting the initiation, progression, and spread of neoplasms.

Targeted Proteomics Reveals Functional Targets for Early Diabetes Susceptibility in Young Adults

BACKGROUND

The circulating proteome may encode early pathways of diabetes susceptibility in young adults for surveillance and intervention. Here, we define proteomic correlates of tissue phenotypes and diabetes in young adults.

METHODS

We used penalized models and principal components analysis to generate parsimonious proteomic signatures of diabetes susceptibility based on phenotypes and on diabetes diagnosis across 184 proteins in >2000 young adults in the CARDIA (Coronary Artery Risk Development in Young Adults study; mean age, 32 years; 44% women; 43% Black; mean body mass index, 25.6±4.9 kg/m2), with validation against diabetes in >1800 individuals in the FHS (Framingham Heart Study) and WHI (Women's Health Initiative).

RESULTS

In 184 proteins in >2000 young adults in CARDIA, we identified 2 proteotypes of diabetes susceptibility-a proinflammatory fat proteotype (visceral fat, liver fat, inflammatory biomarkers) and a muscularity proteotype (muscle mass), linked to diabetes in CARDIA and WHI/FHS. These proteotypes specified broad mechanisms of early diabetes pathogenesis, including transorgan communication, hepatic and skeletal muscle stress responses, vascular inflammation and hemostasis, fibrosis, and renal injury. Using human adipose tissue single cell/nuclear RNA-seq, we demonstrate expression at transcriptional level for implicated proteins across adipocytes and nonadipocyte cell types (eg, fibroadipogenic precursors, immune and vascular cells). Using functional assays in human adipose tissue, we demonstrate the association of expression of genes encoding these implicated proteins with adipose tissue metabolism, inflammation, and insulin resistance.

CONCLUSIONS

A multifaceted discovery effort uniting proteomics, underlying clinical susceptibility phenotypes, and tissue expression patterns may uncover potentially novel functional biomarkers of early diabetes susceptibility in young adults for future mechanistic evaluation.

Paraoxonase 2 (PON2) plays a limited role in murine lung tumorigenesis

Paraoxonase 2 (PON2) is a multifunctional intracellular enzyme that has received growing attention for its ability to modulate various aspects of normal and malignant cellular physiology. Recent research has revealed that PON2 is upregulated in tissues from patients with various types of solid tumors and hematologic cancers, likely due to its ability to suppress oxidative stress and evade apoptosis. However, the effects of PON2 on pulmonary oncogenesis are unknown. Here, we conducted studies to investigate how PON2 influences lung cancer cell proliferation in vitro and lung tumorigenesis in vivo using a variety of cellular and animal models. It was found that PON2 expression deficiency hampered the proliferation of cultured lung cancer cells with concomitant cell cycle arrest at the G1 phase. In addition, the loss of endogenous PON2 expression impaired key aspects of oxidative metabolism in lung adenocarcinoma cells. Moreover, we investigated how the interplay between PON2 expression in lung tumors and host mice influences lung tumor initiation and progression. PON2 status in both transplanted tumor cells and mice failed to influence the development of subcutaneously grafted Lewis lung carcinoma (LLC) tumors, orthotopically implanted LLC tumors, and oncogenic Kras-driven primary lung adenocarcinoma tumors. Importantly, the frequencies of tumor-infiltrating myeloid subsets that include myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages were not impacted by PON2 expression in LLC tumor-bearing mice. Overall, our studies indicate that PON2 plays a limited role in murine lung tumorigenesis.

Plasma paraoxonase-1 activity levels in patients with type 2 diabetes mellitus in Lagos State University Teaching Hospital, Lagos, Southwest Nigeria: a cross-sectional study

Introduction

paraoxonase 1 (PON1) is a high-density lipoprotein (HDL) associated enzyme that has anti-inflammatory, anti-atherogenic, and antioxidant functions. PON1 is noted to be a determinant of resistance to the development of atherosclerosis through hydrolysis of phospholipid and cholesteryl ester hydroperoxides. This study was designed to assess PON1 activity levels among patients with type 2 diabetes mellitus (T2DM) in Southwest Nigeria.

Methods

this was a cross-sectional study done over a period of six months. A total of 138 participants; 69 with T2DM and 69 apparently healthy controls were recruited for this study. Fasting plasma glucose (FPG), HDL cholesterol (HDL-c), and PON1 activity were analyzed in the participants. The comparison of the mean between the groups of participants was assessed using the independent student t-test while the Mann-Whitney U test was used to compare two medians. The p-value was set at 0.05.

Results

mean age for participants with T2DM was 54.90 ± 8.1 years and the healthy control group was 54.12 ± 8.4 years, with a p-value of 0.549. The male-to-female ratio was 0.47 for both participants with T2DM and healthy controls. Participants with T2DM had significantly higher median glucose concentration of 109.18 mg/dl compared with 82.58 mg/dl among controls, p-value <0.001. Median serum HDL-c was lower in diabetics compared to controls (52.66 mg/dl vs 57.92 mg/dl; p-value < 0.001). PON1 activity was lower in T2DM compared with that of the controls (690.11 pmol/min/ml vs 3379.7 pmol/min/ml; p-value <0.001). Paroxonase 1 showed a non-significant positive correlation with HDL-c and a negative correlation with FPG, and body mass index (BMI).

Conclusion

these findings suggest that PON1 activity is lower in T2DM compared to healthy controls and a lower PON1 activity level was seen among female diabetics compared with the male diabetics.

Biomarker signature and pathophysiological pathways in patients with chronic heart failure and metabolic syndrome

AIM

The comorbidities that collectively define metabolic syndrome are common in patients with heart failure. However, the role of metabolic syndrome in the pathophysiology of heart failure is not well understood. We therefore investigated the clinical and biomarker correlates of metabolic syndrome in patients with heart failure.

METHODS AND RESULTS

In 1103 patients with heart failure, we compared the biomarker expression using a panel of 363 biomarkers among patients with (n = 468 [42%]) and without (n = 635 [58%]) metabolic syndrome. Subsequently, a pathway overrepresentation analysis was performed to identify key biological pathways. Findings were validated in an independent cohort of 1433 patients with heart failure of whom 615 (43%) had metabolic syndrome. Metabolic syndrome was defined as the presence of three or more of five criteria, including central obesity, elevated serum triglycerides, reduced high-density lipoprotein cholesterol, insulin resistance and hypertension. The most significantly elevated biomarkers in patients with metabolic syndrome were leptin (log2 fold change 0.92, p = 5.85 × 10^-21 ), fatty acid-binding protein 4 (log2 fold change 0.61, p = 1.21 × 10^-11 ), interleukin-1 receptor antagonist (log2 fold change 0.47, p = 1.95 × 10^-13 ), tumour necrosis factor receptor superfamily member 11a (log2 fold change 0.35, p = 4.16 × 10^-9 ), and proto-oncogene tyrosine-protein kinase receptor Ret (log2 fold change 0.31, p = 4.87 × 10^-9 ). Network analysis identified 10 pathways in the index cohort and 6 in the validation cohort, all related to inflammation. The primary overlapping pathway in both the index and validation cohorts was up-regulation of the natural killer cell-mediated cytotoxicity pathway.

CONCLUSION

Metabolic syndrome is highly prevalent in heart failure and is associated with biomarkers and pathways relating to obesity, lipid metabolism and immune responses underlying chronic inflammation.

Paraoxonase-2 contributes to promoting lipid metabolism and mitochondrial function via autophagy activation

Non-alcoholic fatty liver disease (NAFLD) is an increasingly prevalent immuno-metabolic disease that can progress to hepatic cirrhosis and cancer. NAFLD pathogenesis is extremely complex and is characterized by oxidative stress, impaired mitochondrial function and lipid metabolism, and cellular inflammation. Thus, in-depth research on its underlying mechanisms and subsequent investigation into a potential drug target that has overarching effects on these features will help in the discovery of effective treatments for NAFLD. Our study examines the role of endogenous paraoxonase-2 (PON2), a membrane protein with reported antioxidant activity, in an in vitro cell model of NAFLD. We found that the hepatic loss of PON2 activity aggravated steatosis and oxidative stress under lipotoxic conditions, and our transcriptome analysis revealed that the loss of PON2 disrupts the activation of numerous functional pathways closely related to NAFLD pathogenesis, including mitochondrial respiratory capacity, lipid metabolism, and hepatic fibrosis and inflammation. We found that PON2 promoted the activation of the autophagy pathway, specifically the mitophagy cargo sequestration, which could potentially aid PON2 in alleviating oxidative stress, mitochondrial dysfunction, lipid accumulation, and inflammation. These results provide a mechanistic foundation for the prospect of PON2 as a drug target, leading to the development of novel therapeutics for NAFLD.

Redox signaling at the crossroads of human health and disease

Redox biology is at the core of life sciences, accompanied by the close correlation of redox processes with biological activities. Redox homeostasis is a prerequisite for human health, in which the physiological levels of nonradical reactive oxygen species (ROS) function as the primary second messengers to modulate physiological redox signaling by orchestrating multiple redox sensors. However, excessive ROS accumulation, termed oxidative stress (OS), leads to biomolecule damage and subsequent occurrence of various diseases such as type 2 diabetes, atherosclerosis, and cancer. Herein, starting with the evolution of redox biology, we reveal the roles of ROS as multifaceted physiological modulators to mediate redox signaling and sustain redox homeostasis. In addition, we also emphasize the detailed OS mechanisms involved in the initiation and development of several important diseases. ROS as a double‐edged sword in disease progression suggest two different therapeutic strategies to treat redox‐relevant diseases, in which targeting ROS sources and redox‐related effectors to manipulate redox homeostasis will largely promote precision medicine. Therefore, a comprehensive understanding of the redox signaling networks under physiological and pathological conditions will facilitate the development of redox medicine and benefit patients with redox‐relevant diseases.

Multi-Omics Characterization of Type 2 Diabetes Mellitus-Induced Cognitive Impairment in the db/db Mouse Model

Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder frequently accompanied by cognitive impairment. Contributing factors such as modern lifestyle, genetic predisposition, and gene environmental interactions have been postulated, but the pathogenesis remains unclear. In this study, we attempt to investigate the potential mechanisms and interventions underlying T2DM-induced cognitive deficits from the brain–gut axis perspective. A combined analysis of the brain transcriptome, plasma metabolome, and gut microbiota in db/db mice with cognitive decline was conducted. Transcriptome analysis identified 222 upregulated gene sets and 85 downregulated gene sets, mainly related to mitochondrial respiratory, glycolytic, and inflammation. In metabolomic analysis, a total of 75 significantly altered metabolites were identified, correlated with disturbances of glucose, lipid, bile acid, and steroid metabolism under disease state. Gut microbiota analysis suggested that the species abundance and diversity of db/db mice were significantly increased, with 23 significantly altered genus detected. Using the multi-omics integration, significant correlations among key genes (n = 33), metabolites (n = 41), and bacterial genera (n = 21) were identified. Our findings suggest that disturbed circulation and brain energy metabolism, especially mitochondrial-related disturbances, may contribute to cognitive impairment in db/db mice. This study provides novel insights into the functional interactions among the brain, circulating metabolites, and gut microbiota.

Insights into the role of paraoxonase 2 in human pathophysiology

Paraoxonase 2 (PON2) is a ubiquitously expressed intracellular enzyme that is known to have a protective role from oxidative stress. Clinical studies have also demonstrated the significance of PON2 in the manifestation of cardiovascular and several other diseases, and hence, it is considered an important biomarker. Recent findings of its expression in brain tissue suggest its potential protective effect on oxidative stress and neuroinflammation. Polymorphisms of PON2 in humans are a risk factor in many pathological conditions, suggesting a possible mechanism of its anti-oxidative property probably through lactonase activity. However, exogenous factors may also modulate the expression and activity of PON2. Hence, this review aims to report the mechanism by which PON2 expression is regulated and its role in oxidative stress disorders such as neurodegeneration and tumor formation. The role of PON2 owing to its lactonase activity in bacterial infectious diseases and association of PON2 polymorphism with pathological conditions are also highlighted.

Insights into the role of paraoxonase 2 in human pathophysiology

Paraoxonase 2 (PON2) is a ubiquitously expressed intracellular enzyme that is known to have a protective role from oxidative stress. Clinical studies have also demonstrated the significance of PON2 in the manifestation of cardiovascular and several other diseases, and hence, it is considered an important biomarker. Recent findings of its expression in brain tissue suggest its potential protective effect on oxidative stress and neuroinflammation. Polymorphisms of PON2 in humans are a risk factor in many pathological conditions, suggesting a possible mechanism of its anti-oxidative property probably through lactonase activity. However, exogenous factors may also modulate the expression and activity of PON2. Hence, this review aims to report the mechanism by which PON2 expression is regulated and its role in oxidative stress disorders such as neurodegeneration and tumor formation. The role of PON2 owing to its lactonase activity in bacterial infectious diseases and association of PON2 polymorphism with pathological conditions are also highlighted.

Paraoxonase 2 is an ER chaperone that regulates the epithelial Na+ channel

The mammalian paraoxonases (PONs) have been linked to protection against oxidative stress. However, the physiological roles of members in this family (PON1, PON2, and PON3) are still being characterized. PON2 and PON3 are expressed in the aldosterone-sensitive distal nephron of the kidney and have been shown to negatively regulate expression of the epithelial sodium channel (ENaC), a trimeric ion channel that orchestrates salt and water homeostasis. To date, the nature of this phenomenon has not been explored. Therefore, to investigate the mechanism by which PON2 regulates ENaC, we expressed PON2 along with the ENaC subunits in fisher rat thyroid (FRT) cells, a system that is amenable to biochemical analyses of ENaC assembly and trafficking. We found that PON2 primarily resides in the endoplasmic reticulum (ER) in FRT cells, and its expression reduces the abundance of each ENaC subunit, reflecting enhanced subunit turnover. In contrast, no effect on the levels of mRNAs encoding the ENaC subunits was evident. Inhibition of lysosome function with chloroquine or NH4Cl did not alter the inhibitory effect of PON2 on ENaC expression. In contrast, PON2 accelerates ENaC degradation in a proteasome-dependent manner and acts before ENaC subunit ubiquitination. As a result of enhanced ENaC subunit ubiquitination and degradation, both channel surface expression and ENaC-mediated Na+ transport in FRT cells were reduced by PON2. Together, our data suggest that PON2 functions as an ER chaperone to monitor ENaC biogenesis and redirects the channel for ER-associated degradation.

Paraoxonase 2 protects against the CML mediated mitochondrial dysfunction through modulating JNK pathway in human retinal cells

BACKGROUND

Paraoxonase 2 (PON2) a known anti-apoptotic protein, has not been explored against N^ε-(carboxymethyl)lysine (CML), induced mitochondrial dysfunction and apoptosis in human retinal cells. Hence this present study aims to investigate the potential role of PON2 in mitigating CML-induced mitochondrial dysfunction in these cells.

METHODS

PON2 protein was quantified in HRECs (Human retinal endothelial cells), ARPE-19 (Retinal pigment epithelial cells) cells upon CML treatment and also in cadaveric diabetic retina vs respective controls. ROS production, mitochondrial membrane potential (MMP), mitochondrial permeability transition pore (mPTP) opening, the release of Cyt-c, Bax, Caspase-3, Fis1, Mfn1, Mfn2, mitochondrial morphology, and the signaling pathway was assessed using DCFDA, JC-1, CoCl₂, immunofluorescence or western blotting analysis in both loss-of-function or gain-of-function experiments.

RESULTS

PON2 protein was downregulated in HREC and ARPE-19 cells upon CML treatment as well as in the diabetic retina (p = 0.035). Decrease in PON2 augments Fis1 expression resulting in fragmentation of mitochondria and enhances the ROS production, decreases MMP, facilitates mPTP opening, and induces the release of Cyt-c, which activates the pro-apoptotic pathway. Whereas PON2 overexpression similar to SP600125 (a specific JNK inhibitor) was able to decrease Fis1 (p = 0.036) and reverse the Bcl-2 and Bax ratio, and inhibit the JNK1/2 signaling pathway.

CONCLUSION

Our results confirm that PON2 has an anti-apoptotic role against the CML mediated mitochondrial dysfunction and inhibits apoptosis through the JNK-Fis1 axis.

GENERAL SIGNIFICANCE

We hypothesis that enhancing PON2 may provide a better therapeutic potential against diabetic vascular disease.

High density lipoproteins and oxidative stress in breast cancer

Breast cancer is one of the main leading causes of women death. In recent years, attention has been focused on the role of lipoproteins, alterations of cholesterol metabolism and oxidative stress in the molecular mechanism of breast cancer. A role for high density lipoproteins (HDL) has been proposed, in fact, in addition to the role of reverse cholesterol transport (RCT), HDL exert antioxidant and anti-inflammatory properties, modulate intracellular cholesterol homeostasis, signal transduction and proliferation. Low levels of HDL-Cholesterol (HDL-C) have been demonstrated in patients affected by breast cancer and it has been suggested that low levels of HDL-C could represent a risk factor of breast cancer. Contrasting results have been observed by other authors. Recent studies have demonstrated alterations of the activity of some enzymes associated to HDL surface such as Paraoxonase (PON1), Lecithin-Cholesterol Acyltransferase (LCAT) and Phospholipase A2 (PLA2). Higher levels of markers of lipid peroxidation in plasma or serum of patients have also been observed and suggest dysfunctional HDL in breast cancer patients. The review summarizes results on levels of markers of oxidative stress of plasma lipids and on alterations of enzymes associated to HDL in patients affected by breast cancer. The effects of normal and dysfunctional HDL on human breast cancer cells and molecular mechanisms potentially involved will be also reviewed.

Association of M55L and Q192R polymorphisms of paraoxonase 1 gene (PON1) with recurrent pregnancy loss risk: A case-control study

Background

Recurrent pregnancy loss (RPL) refers to the incidence of two or more abortions before the first half of pregnancy. Oxidative stress has been hypothesized to play a central role in RPL.

Objective

To investigate the relationship between Q192R and L55M polymorphisms of PON1 as antioxidant enzyme and the risk of RPL.

Materials and Methods

In this case–control study, 110 women with RPL (case) and 110 healthy fertile women (control) referred to the Research and Clinical Center for Infertility, Shiraz, Iran were enrolled. Genomic DNA was extracted from the peripheral blood in all participants. Polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism method.

Results

Statistical analysis of Q192R polymorphism showed a significant difference for the RR genotype between the case and control group (OR = 11, CI = 1.39–86.87, p = 0.005) but none for the QR and QQ genotypes. No significant association was observed between the R and Q allelic frequency in the RPL participants compared to the control group (p = 0.53). Also, statistical analysis of the L55M polymorphism for MM genotype in the case group compared with the control group showed a significant difference (OR = 3.59, CI = 0.97–13.30, p = 0.042), but none for the LM and LL genotypes.

Conclusion

The findings showed a significant correlation between the Q192R polymorphisms and the L55M PON1 enzyme and RPL in this study population.

Histological and biochemical investigation of the renoprotective effects of metformin in diabetic and prostate cancer model

BACKGROUND

Diabetes and cancer have common physiological and biochemical mechanisms. Metformin is the preferred drug of choice for the treatment of diabetes. Prostate cancer can be modeled in by injection of MAT-Lylu cells. A model of diabetes in rats is induced by streptozotocin injectıon. In the current study, we explored the mechanisms by which diabetes accelerates cancer, and evaluated the effects of metformin to know whether it has any impact against the damage caused by cancer and diabetic + cancer via histopathological and biochemical parameters of kidney tissue.

METHODS

The experiment was carried out in rats. Groups 1-Control, 2- Diabetic, 3-Cancer, 4-Diabetic + cancer, 5-Diabetic + cancer + metformin, 6-Cancer + metformin. Metformin treatment was applied by gavage every day. The research ended on the 14th day. The collected kidney tissue sections were stained with Hematoxylin-Eosin.

RESULTS

Histological evaluation showed moderate to severe damage to the kidney tissue following diabetic and cancer processess. In diabetic, cancer and diabetic + cancer groups, reduced glutathione levels, total antioxidant status, sodium/potassium-ATPase and paraoxonase1 activities were found to be significantly abated. While advanced oxidized protein products, lipid peroxidation, nitric oxide, tumor necrosis factor-alpha, reactive oxygen species levels, total oxidant status, catalase, superoxide dismutase, glutathione-related antioxidant enzymes, myeloperoxidase, and arginase activities were significantly raised. The administration of metformin reversed these defects. The outcome of the reveals that histopathological and biochemical damage in cancer and diabetes + cancer groups decreased in the groups that received metformin.

CONCLUSION

In conclusion, metformin treatment can be considered an adjuvant candidate for kidney tissue in diabetes, prostate cancer and cancer therapy related damage.

The Interplay between Oxidative Stress, Inflammation and Angiogenesis in Bladder Cancer Development

In 2018, 550,000 people were diagnosed with bladder cancer (BC), of which nearly 200,000 people died. Moreover, men are 4 times more likely than women to be diagnosed with BC. The risk factors include exposure to environmental and occupational chemicals, especially tobacco smoke, benzidine and genetic factors. Despite numerous studies, the molecular basis of BC development remains unclear. A growing body of evidence suggests that inflammation, oxidant-antioxidant imbalance and angiogenesis disorders may play a significant role in the development and progression of bladder cancer. The patients with bladder cancer were characterised by an increased level of reactive oxygen species (ROS), the products of lipid peroxidation, proinflammatory cytokines and proangiogenic factors as compared to controls. Furthermore, it was shown that polymorphisms localised in genes associated with these pathways may modulate the risk of BC. Interestingly, ROS overproduction may induce the production of proinflammatory cytokines, which finally activated angiogenesis. Moreover, the available literature shows that both inflammation and oxidative stress may lead to activation of angiogenesis and tumour progression in BC patients.

Early Protein Markers of Necrotizing Enterocolitis in Plasma of Preterm Pigs Exposed to Antibiotics

Background: Most hospitalized preterm infants receive antibiotics in the first days of life to prevent or treat infections. Short-term, early antibiotic treatment may also prevent the microbiota-dependent gut inflammatory disorder, necrotizing enterocolitis (NEC). It remains a challenge to predict NEC, and a few early blood diagnostic markers exist. Using preterm pigs as model for infants, blood parameters and plasma proteins affected by early progression of NEC were profiled in preterm pigs subjected to oral, systemic, or no antibiotics after preterm birth.

Methods: Preterm newborn pigs were treated with saline (CON) or antibiotics (ampicillin, gentamicin, and metronidazole) given enterally (ENT) or parenterally (PAR), and fed formula for 4 days to induce variable microbiome-dependent sensitivities to NEC. The gut was collected for macroscopic scoring of NEC lesions and blood for hematology, blood biochemistry, and LC/MS-based plasma proteomics. Statistical modeling was applied to detect plasma proteins affected by NEC and/or antibiotics.

Results: Analyzed across different antibiotic regimens, NEC progression was associated with altered blood parameters and abundance of 89 plasma proteins that were functionally involved in extracellular membrane destruction, lipid metabolism, coagulopathy, and acute phase response. Large NEC-related changes were observed in abundance of RBP4, FGA, AHSG, C5, PTPRG, and A-1-antichymotrypsin 2, indicating potential serving as early markers of NEC. Conversely, antibiotic treatment, independent of NEC, affected only 4 proteins with main differences found between ENT and CON pigs.

Conclusion: Early postnatal development of NEC lesions is associated with marked plasma protein changes that may be used for early NEC diagnosis.

Paraoxonase 3 functions as a chaperone to decrease functional expression of the epithelial sodium channel

The paraoxonase (PON) family comprises three highly conserved members: PON1, PON2, and PON3. They are orthologs of Caenorhabditis elegans MEC-6, an endoplasmic reticulum-resident chaperone that has a critical role in proper assembly and surface expression of the touch-sensing degenerin channel in nematodes. We have shown recently that MEC-6 and PON2 negatively regulate functional expression of the epithelial Na⁺ channel (ENaC), suggesting that the chaperone function is conserved within this family. We hypothesized that other PON family members also modulate ion channel expression. Pon3 is specifically expressed in the aldosterone-sensitive distal tubules in the mouse kidney. We found here that knocking down endogenous Pon3 in mouse cortical collecting duct cells enhanced Na⁺ transport, which was associated with increased γENaC abundance. We further examined Pon3 regulation of ENaC in two heterologous expression systems, Fisher rat thyroid cells and Xenopus oocytes. Pon3 coimmunoprecipitated with each of the three ENaC subunits in Fisher rat thyroid cells. As a result of this interaction, the whole-cell and surface abundance of ENaC α and γ subunits was reduced by Pon3. When expressed in oocytes, Pon3 inhibited ENaC-mediated amiloride-sensitive Na⁺ currents, in part by reducing the surface expression of ENaC. In contrast, Pon3 did not alter the response of ENaC to chymotrypsin-mediated proteolytic activation or [2-(trimethylammonium)ethyl]methanethiosulfonate-induced activation of αβ_S518Cγ, suggesting that Pon3 does not affect channel open probability. Together, our results suggest that PON3 regulates ENaC expression by inhibiting its biogenesis and/or trafficking.

Paraoxonase 3: Structure and Its Role in Pathophysiology of Coronary Artery Disease

Spanning three decades in research, Paraoxonases (PON1) carried potential of dealing with neurotoxicity of organophosphates entering the circulation and preventing cholinergic crisis. In the past few years, the Paraoxonase multigene family (PON1, PON2, PON3) has been shown to play an important role in pathogenesis of cardiovascular disorders including coronary artery disease (CAD). The PON genes are clustered in tandem on the long arm of human chromosome 7 (q21, 22). All of them have been shown to act as antioxidants. Of them, PON3 is the least studied member as its exact physiological substrate is still not clear. This has further led to limitation in our understanding of its role in pathogenesis of CAD and development of the potential therapeutic agents which might modulate its activity, expression in circulation and tissues. In the present review, we discuss the structure and activity of human PON3 enzyme and its Single nucleotide variants that could potentially lead to new clinical strategies in prevention and treatment of CAD.

Alterations of Antioxidant Enzymes and Biomarkers of Nitro-oxidative Stress in Tissues of Bladder Cancer

Bladder cancer (BC) is one of the most common tumors found in the urinary bladder for both male and female in western countries. In vitro and in vivo studies suggest that high levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and oxidative stress play a crucial role in human cancer. Low concentration of ROS and RNS is indispensable for cell survival and proliferation. However, high concentration of ROS and RNS can exert a cytotoxic effect. Increased oxidative stress is a result of either increased ROS/RNS production or a decrease of antioxidant defense mechanisms. A literature search was carried out on PubMed, Medline, and Google Scholar for articles in English published up to May 2018 using the following keywords: oxidative stress, antioxidants, reactive oxygen species, lipid peroxidation, paraoxonase, urinary bladder cancer, and nitric oxide. Literature data demonstrate that BC is associated with oxidative stress and with an imbalance between oxidants and antioxidant enzymes. Markers of lipid peroxidation, protein and nucleic acid oxidation are significantly higher in tissues of patients with BC compared with control groups. A decrease of activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione, and paraoxonase) has also been demonstrated. The imbalance between oxidants and antioxidants could have a potential role in the etiology and progression of bladder cancer.

Association between paraoxonase-1 gene Q192R and L55M polymorphisms and risk of gastric cancer: A case-control study from Iran

The aim of the present study was to examine the relation between two paraoxonase1 (PON1) polymorphisms, Q192R and L55M and susceptibility to gastric cancer in an Iranian population. In this case-control study the PON1 polymorphisms were assessed in 90 gastric cancer patients and 90 healthy controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Regarding PON1 Q192R polymorphism, a significant increase in the R allele in the patient group compared with the controls (p value = 0.0006) While the Q allele was more frequent in the control group. No significant difference was found in the genotype or allele frequency of the L55M polymorphism between healthy individuals and patients with gastric cancer. Our results demonstrated the protective effect of Q allele against gastric cancer.

Paraoxonase 2 protects against acute myocardial ischemia-reperfusion injury by modulating mitochondrial function and oxidative stress via the PI3K/Akt/GSK-3β RISK pathway

OBJECTIVE

To investigate the novel role of Paraoxonase 2 (PON2) in modulating acute myocardial ischemia-reperfusion injury (IRI).

APPROACH

IRI was induced both in vivo and ex vivo in male, C57BL6/J (WT) and PON2-deficient (PON-def) mice. In addition, in vitro hypoxia-reoxygenation injury (HRI) was induced in H9c2 cells expressing empty vector (H9c2-EV) or human PON2 (H9c2-hPON2) ± LY294002 (a potent PI3K inhibitor). Infarct size, PON2 gene expression, mitochondrial calcium retention capacity (CRC), reactive oxygen species (ROS) generation, mitochondrial membrane potential, CHOP and pGSK-3β protein levels, and cell apoptosis were evaluated.

RESULTS

PON2 gene expression is upregulated in WT mice following in vivo IRI. PON2-def mice exhibit a 2-fold larger infarct, increased CHOP levels, and reduced pGSK-3β levels compared to WT controls. Global cardiac mitochondria isolated from PON2-def mice exhibit reduced CRC and increased ROS production. Cardiomyocytes isolated from PON2-def mice subjected to ex vivo IRI have mitochondria with reduced CRC (also seen under non-IRI conditions), and increased ROS generation and apoptosis compared to WT controls. PON2 knockdown in H9c2 cells subjected to HRI leads to an increase in mitochondrial membrane depolarization. H9c2-hPON2 cells exhibit i) improvement in mitochondrial membrane potential, pGSK-3β levels and mitochondrial CRC, and ii) decrease in CHOP levels, mitochondrial ROS generation and cell apoptosis, when compared to H9c2-EV controls. Treatment with LY294002 resulted in a decrease of mitochondrial CRC and increase in mitochondrial ROS production and cell apoptosis in the H9c2-hPON2 group versus H9c2-EV controls.

CONCLUSION

PON2 protects against acute myocardial IRI by reducing mitochondrial dysfunction and oxidative stress in cardiomyocytes via activation of the PI3K/Akt/GSK-3β RISK pathway.

Genetic polymorphisms in complement receptor 1 gene and its association with HBV-related liver disease: A case-control study

BACKGROUND

Several investigators have reported that complement receptor 1 (CR1) likely play a role in the pathogenesis of tumors, autoimmune and inflammatory diseases. However, the association of genetic polymorphisms of CR1 with risk of hepatitis B virus (HBV)-related liver disease remains unexplored.

METHODS

In a case-control study of 399 HBV-related liver disease patients and 227 healthy controls, we genotyped two SNPs in CR1 (rs3811381 and rs2274567) and assessed their associations with risk of HBV-related liver disease.

RESULTS

No significant differences were observed in the frequency distribution of genotypes or alleles between CR1 rs3811381 and rs2274567 polymorphisms in patients and controls. However, stratification analysis indicated that these two CR1 polymorphisms may contribute to the risk of HBV- hepatocellular carcinoma (HCC) and chronic hepatitis B (CHB) in subgroups of males, alcohol drinkers and nonsmokers. Further, our results showed that the rs3811381 polymorphism may contribute to HBV-HCC risk in subgroups of older and younger subjects, while the G allele, AG and the combined AG + GG genotypes of rs2274567 may be risk factors for HBV-HCC in younger subjects. In addition, our results indicated that subjects who carried the rs3811381 G allele and the rs2274567 AG genotype were at decreased risk of HBV- liver cirrhosis (LC) in subgroups of females.

CONCLUSIONS

Our results support the hypothesis that the CR1 gene rs3811381 and rs2274567 polymorphisms may contribute to HBV-HCC and HBV-CHB risk, particularly in subgroups of males, alcohol drinkers, nonsmokers, while these two CR1 polymorphisms were found to associate with decreased risk of HBV-LC, particularly in females. Further validation of these results is warranted.

Paraoxonase 3 is involved in the multi-drug resistance of esophageal cancer

Background

Drug resistance prevents the effective treatment of cancers. DNA methylation has been found to participate in the development of cancer drug resistance.

Methods

We performed the wound-healing and invasion assays to test the effect of the paraoxonase gene PON3 on esophageal cancer (EC) cells. In addition, in vivo EC-derived tumor xenografts in nude mice were generated to test the effect of PON3 on the chemoresistance of EC cells.

Results

We found that PON3 is hypermethylated in drug-resistant EC cell line K150, which in-return down-regulates its expression. The following experiments by the forced changes of PON3 level in vitro and in vivo demonstrated that the PON3 expression negatively correlates with drug resistance in EC cells. Further wound-healing and invasion assays showed that PON3 suppresses the migration and invasion of EC cells.

Conclusion

Our data established that PON3 is associated with the EC drug resistance, which may serve as a biomarker for the potential therapeutic treatment of EC.

Electronic supplementary material

The online version of this article (10.1186/s12935-018-0657-1) contains supplementary material, which is available to authorized users.

Paraoxonase 1 knockout rats have impaired T cell development at the CD4/CD8 double-negative to double-positive transition stage

Paraoxonase 1 (PON1) is a high-density lipoprotein-associated enzyme that performs multiple physiological activities. Previous studies suggest that PON1 plays an anti-inflammatory role in the cardiovascular system, although its roles in hematopoiesis and adaptive immunity have not been clarified. To investigate the impact of PON1 on the immune system, we generated PON1-knockout (PON1^−/−) rats using the CRISPR/Cas9 system. The thymus was smaller in PON1^−/− rats than that in wild-type (PON1^+/+) rats. Furthermore, analysis of thymocyte development revealed diminished total T cell numbers and a decrease in CD4⁺, CD8⁺ and double-positive T cells in peripheral blood and thymus from PON1^−/− rats. This may be due to a block in the transition of T cells from the double-negative to the double-positive stage. We also showed that the activation of p38 MAPK phosphorylation contributed to the increased apoptosis and defective T cell development in PON^−/− rats. Therefore, our results indicate that PON1 functions as a novel regulator of T cell development.

Exploring the role of paraoxonase-2 in bladder cancer: analyses performed on tissue samples, urines and cell cultures

The enzyme paraoxonase-2 (PON2) is ubiquitously expressed and exerts its antiapoptotic and antioxidative functions in several intracellular compartments.The aim of this study is to investigate the role of PON2 in bladder cancer (BC). The expression levels of PON2 in paired tumor and normal bladder tissue samples and in urinary exfoliated cells from patients affected with BC and healthy donors were evaluated. Moreover, the effect of PON2 overexpression on tumor cell proliferation and susceptibility to oxidative stress was investigated in human bladder cancer cell line T24.Our results showed that PON2 expression levels were significantly higher in BC compared with non-tumor tissue. In urinary exfoliated cells from BC patients, PON2 mRNA levels showed an inverse correlation with tumor stage (pT). Moreover, PON2 overexpression in T24 cells led to a significant increase in tumor cell proliferation and resistance to oxidative stress.The results obtained showed that PON2 could represent a molecular biomarker for bladder cancer and suggest a potential role of the enzyme as a prognostic factor for this neoplasm.

The role of paraoxonase in cancer

The paraoxonase (PON) gene family includes three proteins, PON1, PON2 and PON3. PON1 and PON3 are both associated with high-density lipoprotein (HDL) particles and exert anti-oxidant and anti-inflammatory properties. PON2 and PON3 are intracellular enzymes which modulate mitochondrial superoxide anion production and endoplasmic reticulum (ER) stress-induced apoptosis. The pleiotropic roles exerted by PONs have been mainly investigated in cardiovascular and neurodegenerative diseases. In recent years, overexpression of PON2 and PON3 has been observed in cancer cells and it has been proposed that both enzymes could be involved in tumor survival and stress resistance. Moreover, a lower activity of serum PON1 has been reported in cancer patients. This review summarizes literature data on the role of PONs in human cancers and their potential role as a target for antitumor drugs.

Regulation of the epithelial Na+ channel by paraoxonase-2

Paraoxonase-2 (PON-2) is a membrane-bound lactonase with unique anti-oxidative and anti-atherosclerotic properties. PON-2 shares key structural elements with MEC-6, an endoplasmic reticulum-resident molecular chaperone in Caenorhabditis elegans MEC-6 modulates the expression of a mechanotransductive ion channel comprising MEC-4 and MEC-10 in touch-receptor neurons. Because pon-2 mRNA resides in multiple rat nephron segments, including the aldosterone-sensitive distal nephron where the epithelial Na⁺ channel (ENaC) is expressed, we hypothesized that PON-2 would similarly regulate ENaC expression. We observed PON-2 expression in aquaporin 2-positive principal cells of the distal nephron of adult human kidney. PON-2 also co-immunoprecipitated with ENaC when co-expressed in HEK293 cells. When PON-2 was co-expressed with ENaC in Xenopus oocytes, ENaC activity was reduced, reflecting a reduction in ENaC surface expression. MEC-6 also reduced ENaC activity when co-expressed in Xenopus oocytes. The PON-2 inhibitory effect was ENaC-specific, as PON-2 had no effect on functional expression of the renal outer medullary potassium channel. PON-2 did not alter the response of ENaC to extracellular Na⁺, mechanical shear stress, or α-chymotrypsin-mediated proteolysis, suggesting that PON-2 did not alter the regulation of ENaC by these factors. Together, our data suggest that PON-2 regulates ENaC activity by modulating its intracellular trafficking and surface expression.

Identification of Predictive DNA Methylation Biomarkers for Chemotherapy Response in Colorectal Cancer

Resistance to 5-Fluorouracil (5-FU) is a major obstacle to the successful treatment of colorectal cancer (CRC) and posed an increased risk of recurrence. DNA methylation has been suggested as one of the underlying mechanisms for recurrent disease and its contribution to the development of drug resistance remains to be clarified. This study aimed to determine the methylation phenotype in CRC for identification of predictive markers for chemotherapy response. We performed DNA methylation profiling on 43 non-recurrent and five recurrent CRC patients using the Illumina Infinium HumanMethylation450 Beadchip assay. In addition, CRC cells with different genetic backgrounds, response to 5-FU and global methylation levels (HT29 and SW48) were treated with 5-FU and DNA methylation inhibitor 5-aza-2′-deoxycytidine (5-azadC). The singular and combined effects of these two drug classes on cell viability and global methylation profiles were investigated. Our genome-wide methylation study on the clinical specimens showed that recurrent CRCs exhibited higher methylation levels compared to non-recurrent CRCs. We identified 4787 significantly differentially methylated genes (P < 0.05); 3112 genes were hyper- while 1675 genes were hypomethylated in the recurrent group compared to the non-recurrent. Fifty eight and 47 of the significantly hypermethylated and hypomethylated genes have an absolute recurrent/non-recurrent methylation difference of ≥20%. Most of the hypermethylated genes were involved in the MAPK signaling pathway which is a key regulator for apoptosis while the hypomethylated genes were involved in the PI3K-AKT signaling pathway and proliferation process. We also demonstrate that 5-azadC treatment enhanced response to 5-FU which resulted in significant growth inhibition compared to 5-FU alone in hypermethylated cell lines SW48. In conclusion, we found the evidence of five potentially biologically important genes in recurrent CRCs that could possibly serve as a new potential therapeutic targets for patients with chemoresistance. We postulate that aberrant methylation of CCNEI, CCNDBP1, PON3, DDX43, and CHL1 in CRC might be associated with the recurrence of CRC and 5-azadC-mediated restoration of 5-FU sensitivity is mediated at least in part by MAPK signaling pathway.

Downregulation of human paraoxonase 1 (PON1) by organophosphate pesticides in HepG2 cells

Paraoxonase 1 (PON1) is a calcium-dependent esterase synthesized primarily in the liver and secreted into the plasma where it is associated with high-density lipoproteins (HDL). PON1 hydrolyzes and detoxifies some toxic metabolites of organophosphorus compounds (OPs) such as methyl parathion and chlorpyrifos. Thus, PON1 activity and expression levels are important for determining susceptibility against OPs poisoning. Some studies have demonstrated that OPs can modulate gene expression through interactions with nuclear receptors. In this study, we evaluated the effects of methyl parathion and chlorpyrifos on the modulation of PON1 in Human Hepatocellular Carcinoma (HepG2) cells by real-time PCR, PON1 activity assay, and western blot. The results showed that the treatments with methyl parathion and chlorpyrifos decreased PON1 mRNA and immunoreactive protein and increased inflammatory cytokines in HepG2 cells. The effects of methyl parathion and chlorpyrifos on the downregulation of PON1 gene expression in HepG2 cells may provide evidence of OPs cytotoxicity related to oxidative stress and an inflammatory response. A decrease in the expression of the PON1 gene may increase the susceptibility to OPs intoxication and the risk of diseases related to inflammation and oxidative stress. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 490-500, 2017.

Immune and biochemical responses in skin differ between bovine hosts genetically susceptible and resistant to the cattle tick Rhipicephalus microplus

Background

Ticks attach to and penetrate their hosts’ skin and inactivate multiple components of host responses in order to acquire a blood meal. Infestation loads with the cattle tick, Rhipicephalus microplus, are heritable: some breeds carry high loads of reproductively successful ticks, whereas in others, few ticks feed and reproduce efficiently.

Methods

In order to elucidate the mechanisms that result in the different outcomes of infestations with cattle ticks, we examined global gene expression and inflammation induced by tick bites in skins from one resistant and one susceptible breed of cattle that underwent primary infestations with larvae and nymphs of R. microplus. We also examined the expression profiles of genes encoding secreted tick proteins that mediate parasitism in larvae and nymphs feeding on these breeds.

Results

Functional analyses of differentially expressed genes in the skin suggest that allergic contact-like dermatitis develops with ensuing production of IL-6, CXCL-8 and CCL-2 and is sustained by HMGB1, ISG15 and PKR, leading to expression of pro-inflammatory chemokines and cytokines that recruit granulocytes and T lymphocytes. Importantly, this response is delayed in susceptible hosts. Histopathological analyses of infested skins showed inflammatory reactions surrounding tick cement cones that enable attachment in both breeds, but in genetically tick-resistant bovines they destabilized the cone. The transcription data provided insights into tick-mediated activation of basophils, which have previously been shown to be a key to host resistance in model systems. Skin from tick-susceptible bovines expressed more transcripts encoding enzymes that detoxify tissues. Interestingly, these enzymes also produce volatile odoriferous compounds and, accordingly, skin rubbings from tick-susceptible bovines attracted significantly more tick larvae than rubbings from resistant hosts. Moreover, transcripts encoding secreted modulatory molecules by the tick were significantly more abundant in larval and in nymphal salivary glands from ticks feeding on susceptible bovines.

Conclusions

Compared with tick-susceptible hosts, genes encoding enzymes producing volatile compounds exhibit significantly lower expression in resistant hosts, which may render them less attractive to larvae; resistant hosts expose ticks to an earlier inflammatory response, which in ticks is associated with significantly lower expression of genes encoding salivary proteins that suppress host immunity, inflammation and coagulation.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1945-z) contains supplementary material, which is available to authorized users.

HSP90 inhibitors in the context of heat shock and the unfolded protein response: effects on a primary canine pulmonary adenocarcinoma cell line

BACKGROUND

Agents targeting HSP90 and GRP94 are seldom tested in stressed contexts such as heat shock (HS) or the unfolded protein response (UPR). Tumor stress often activates HSPs and the UPR as pro-survival mechanisms. This begs the question of stress effects on chemotherapeutic efficacy, particularly with drugs targeting chaperones such as HSP90 or GRP94. We tested the utility of several HSP90 inhibitors, including PU-H71 (targeting GRP94), on a primary canine lung cancer line under HS/UPR stress compared to control conditions.

METHODS

We cultured canine bronchoalveolar adenocarcinoma cells that showed high endogenous HSP90 and GRP94 expression; these levels substantially increased upon HS or UPR induction. We treated cells with HSP90 inhibitors 17-DMAG, 17-AAG or PU-H71 under standard conditions, HS or UPR. Cell viability/survival was assayed. Antibody arrays measured intracellular signalling and apoptosis profiles.

RESULTS

HS and UPR had varying effects on cells treated with different HSP90 inhibitors; in particular, HS and UPR promoted resistance to inhibitors in short-term assays, but combinations of UPR stress and PU-H571 showed potent cytotoxic activity in longer-term assays. Array data indicated altered signalling pathways, with apoptotic and pro-survival implications. UPR induction + dual targeting of HSP90 and GRP94 swayed the balance toward apoptosis.

CONCLUSION

Cellular stresses, endemic to tumors, or interventionally inducible, can deflect or enhance chemo-efficacy, particularly with chaperone-targeting drugs. Stress is likely not held accountable when testing new pharmacologics or assessing currently-used drugs. A better understanding of stress impacts on drug activities should be critical in improving therapeutic targeting and in discerning mechanisms of drug resistance.

Antioxidant Functions of the Aryl Hydrocarbon Receptor

The aryl hydrocarbon receptor (AhR) is a transcription factor belonging to the basic helix-loop-helix/PER-ARNT-SIM family. It is activated by a variety of ligands, such as environmental contaminants like polycyclic aromatic hydrocarbons or dioxins, but also by naturally occurring compounds and endogenous ligands. Binding of the ligand leads to dimerization of the AhR with aryl hydrocarbon receptor nuclear translocator (ARNT) and transcriptional activation of several xenobiotic phase I and phase II metabolizing enzymes. It is generally accepted that the toxic responses of polycyclic aromatic hydrocarbons, dioxins, and structurally related compounds are mediated by activation of the AhR. A multitude of studies indicate that the AhR operates beyond xenobiotic metabolism and exerts pleiotropic functions. Increasing evidence points to a protective role of the AhR against carcinogenesis and oxidative stress. Herein, I will highlight data demonstrating a causal role of the AhR in the antioxidant response and present novel findings on potential AhR-mediated antioxidative mechanisms.

Prostate tumor DNA methylation is associated with cigarette smoking and adverse prostate cancer outcomes

BACKGROUND

DNA methylation has been hypothesized as a mechanism for explaining the association between smoking and adverse prostate cancer (PCa) outcomes. This study was aimed at assessing whether smoking is associated with prostate tumor DNA methylation and whether these alterations may explain in part the association of smoking with PCa recurrence and mortality.

METHODS

A total of 523 men had radical prostatectomy as their primary treatment, detailed smoking history data, long-term follow-up for PCa outcomes, and tumor tissue profiled for DNA methylation. Ninety percent of the men also had matched tumor gene expression data. A methylome-wide analysis was conducted to identify differentially methylated regions (DMRs) by smoking status. To select potential functionally relevant DMRs, their correlation with the messenger RNA (mRNA) expression of corresponding genes was evaluated. Finally, a smoking-related methylation score based on the top-ranked DMRs was created to assess its association with PCa outcomes.

RESULTS

Forty DMRs were associated with smoking status, and 10 of these were strongly correlated with mRNA expression (aldehyde oxidase 1 [AOX1], claudin 5 [CLDN5], early B-cell factor 1 [EBF1], homeobox A7 [HOXA7], lectin galactoside-binding soluble 3 [LGALS3], microtubule-associated protein τ [MAPT], protocadherin γ A [PCDHGA]/protocadherin γ B [PCDHGB], paraoxonase 3 [PON3], synaptonemal complex protein 2 like [SYCP2L], and zinc finger and SCAN domain containing 12 [ZSCAN12]). Men who were in the highest tertile for the smoking-methylation score derived from these DMRs had a higher risk of recurrence (odds ratio [OR], 2.29; 95% confidence interval [CI], 1.42-3.72) and lethal disease (OR, 4.21; 95% CI, 1.65-11.78) in comparison with men in the lower 2 tertiles.

CONCLUSIONS

This integrative molecular epidemiology study supports the hypothesis that smoking-associated tumor DNA methylation changes may explain at least part of the association between smoking and adverse PCa outcomes. Future studies are warranted to confirm these findings and understand the implications for improving patient outcomes. Cancer 2016;122:2168-77. © 2016 American Cancer Society.

Systematic review and meta-analysis deciphering the impact of fibrates on paraoxonase-1 status

OBJECTIVE

A significant residual cardiovascular risk is consistently observed in patients treated with statins. A combined treatment with fibrates reduces cardiovascular events in very high-risk patients. Because this is apparently unconnected to an improvement in lipid-related outcomes we hypothesized that the cardioprotective effects of fibrates might be associated with an improvement in paraoxonase-1 (PON1) status.

METHOD

The search for existing evidence, using the Medline, Scopus and Cochrane databases, was systematic and followed the PRISMA statement without restrictions on publication date. We excluded non-clinical and observational studies and we extracted data on baseline and post-treatment values of serum PON1 activity and other measurements of PON1 status.

RESULTS

Nine studies (including 12 treatment arms) in patients with hyperlipidemia, diabetes or metabolic syndrome treated with fibrates, alone or in combination with statins, were included to synthesize results. A meta-analysis of the data using a random-effects model revealed a significant increase in serum PON1 activity following fibrate therapy (WMD: 15.64U/L, 95% CI: 6.94, 24.34, p<0.001), an effect that was robust and not sensitive to any particular study. Subgroup analysis indicated differences in the effect size among types of fibrates and that PON1 alterations were associated with high-density lipoprotein cholesterol changes following fibrate therapy.

CONCLUSIONS

Results indicate a significant PON1-enhancing effect of fibrates. Whether this effect is associated with a clinical benefit, although likely, remains to be further investigated.

Age-dependency of the serum oxidative level in the senescence-accelerated mouse prone 8

Systemic oxidative stress is considered to cause aging. In this study, to estimate the oxidative stress level in senescence-accelerated mouse prone 8 (SAMP8), we evaluated serum reactive oxygen species production and reduction capacity by measurement of Diacron-Reactive Oxygen Metabolites (d-ROM) and Biological Antioxidant Potential (BAP), respectively, with age. SAMP8 showed earlier increase of d-ROM value with age than SAM resistant 1 (SAMR1), the control strain. The BAP level was the highest in adult SAMP8, whereas SAMR1 presented the sustained BAP values between ages. These results indicate that oxidative stress in SAMP8 is higher than SAMR1. Our study is the first detailed report about d-ROM and BAP in SAMP8 and will provide useful fundamental data for future aging studies.

Activity and determinants of cholinesterases and paraoxonase-1 in blood of workers exposed to non-cholinesterase inhibiting pesticides

Pesticide exposure has been associated with different adverse health effects which may be modulated to some extent by paraoxonase-1 (PON1) activity and genetic polymorphisms. This study assessed seasonal variations in PON1 activity (using paraoxon -POase-, phenylacetate -AREase-, diazoxon -DZOase- and dihydrocoumarin -DHCase- as substrates), erythrocyte acetylcholinesterase (AChE) and plasma cholinesterase (using butyrylthiocholine -BuChE- and benzoylcholine -BeChE- as substrates. The study population consisted of intensive agriculture workers regularly exposed to pesticides other than organophosphates and non-exposed controls from Almería (Southeastern Spain). The effect of common genetic polymorphisms of PON1 and BCHE on paraoxonase-1 and cholinesterase activities toward different substrates was also assessed. Linear mixed models were used to compare esterase activities in agricultural workers and control subjects over the two study periods (high and low exposure to pesticides). The significant decrease in AChE and increase in BuChE and BeChE activities observed in workers with respect to control subjects was attributed to pesticide exposure. Workers also had higher levels of AREase, DZOase and, to a lesser extent, of POase, but showed decreased DHCase activity. While PON1 Q192R and PON1 -108C/T gene polymorphisms were significantly associated with all PON1 activities, PON1 L55M showed a significant association with AREase, DZOase and DHCase. BCHE-K (Karlow variant) was significantly associated with lower BeChE activity (but not with BuChE) and BCHE-A (atypical variant) showed no significant association with any cholinesterase activity. These findings suggest that increased PON1, BuChE and BeChE activities in exposed workers might result from an adaptive response against pesticide exposure to compensate for adverse effects at the biochemical level. This response appears to be modulated by PON1 and BCHE gene polymorphisms.

Paraoxonases, mitochondrial dysfunction and non-communicable diseases

The most common non-communicable diseases (NCD) are obesity, cardiovascular disease, diabetes, cancer, chronic respiratory diseases, and neurological diseases. Together, they constitute the commonest cause of death and disability worldwide. Mitochondrial alterations, oxidative stress and inflammation underpin NCD and are molecular mechanisms playing major roles in the disease onset and natural history. Interrelations between the mechanisms of oxidative stress, inflammation and metabolism are, in the broadest sense of energy transformations, being increasingly recognized as part of the problem in NCD. Whether or not oxidative stress and inflammation are the causes or the consequences of cellular disturbances, they do significantly contribute to NCD. Paraoxonases are associated with mitochondria and mitochondria-associated membranes. They modulate mitochondria-dependent superoxide production, and prevent apoptosis. Their overexpression protects mitochondria from endoplasmic reticulum stress and subsequent mitochondrial dysfunction; highlighting that the anti-inflammatory effects of paraoxonases may be mediated, at least in part, by their protective role in mitochondria and associated organelle function. Since oxidative stress is implicated in the development of NCD (as a result of mitochondrial dysfunction), these data suggest that understanding the role and the molecular targets of paraoxonases may provide novel strategies of intervention in the treatment of these important diseases.

Genome-wide DNA methylation profiling of recurrent and non-recurrent chordomas

Chordomas are an aggressive rare type of malignant bone tumors arising from the remnant of the notochord. Chordomas occur mainly in vertebral bones and account for 1-4% of malignant bone tumors. Management and treatment of chordomas are difficult as they are resistant to conventional chemotherapy; therefore, they are mainly treated with surgery and radiation therapy. In this study, we performed DNA methylation profiling of 26 chordomas and normal nucleus pulposus samples plus UCH-1 chordoma cell line using the Illumina Infinium HumanMethylation450 BeadChips. Combined bisulfite restriction analysis and bisulfite sequencing was used to confirm the methylation data. Gene expression was analyzed using RT-PCR before and after 5-aza-2'-deoxycytidine (5-azaDC) treatment of chordoma cell lines. Analysis of the HumanMethylation450 BeadChip data led to the identification of 8,819 loci (2.9%) that were significantly differentially methylated (>0.2 average β-value difference) between chordomas and nucleus pulposus samples (adjusted P < 0.05). Among these, 5,868 probes (66.5%) were hypomethylated, compared to 2,951 (33.5%) loci that were hypermethylated in chordomas compared to controls. From the 2,951 differentially hypermethylated probes, 33.3% were localized in the promoter region (982 probes) and, among these, 104 probes showed cancer-specific hypermethylation. Ingenuity Pathway Analysis indicates that the cancer-specific differentially methylated loci are involved in various networks including cancer disease, nervous system development and function, cell death and survival, cellular growth, cellular development, and proliferation. Furthermore, we identified a subset of probes that were differentially methylated between recurrent and non-recurrent chordomas. BeadChip methylation data was confirmed for these genes and gene expression was shown to be upregulated in methylated chordoma cell lines after treatment with 5-azaDC. Understanding epigenetic changes in chordomas may provide insights into chordoma tumorigenesis and development of epigenetic biomarkers.

Oxidative stress in drug naïve first episode psychosis and antioxidant effects of risperidone

BACKGROUND

Schizophrenia is accompanied by increased lipid peroxidation and nitric oxide (NO) levels and by lowered antioxidant levels. However, the effect of antipsychotic agents on these processes remains unclear. The objective of this study is to determine the oxidative stress (OS) status in drug naïve first-episode psychotic patients (FEP) compared to healthy controls and to delineate the effects of risperidone on these biomarkers.

METHODS

51 drug naive FEP patients and 61 healthy controls were enrolled; FEP patients were reassessed 11 weeks after risperidone treatment. Three OS biomarkers, i.e. lipid hydroperoxides - LOOH, NO metabolites - NOx, and advanced oxidation protein products - AOPP, and two antioxidant biomarkers, i.e. total radical-trapping antioxidant parameter - TRAP, and paraoxonase 1 - PON1, were measured. The Positive and Negative Syndrome Scale (PANSS) and the Calgary Depression Scale for Schizophrenia (CDSS) were used to measure symptoms severity.

RESULTS

Significantly lower PON1 activity and increased TRAP values were found in FEP patients. There were no significant associations between any of the OS/antioxidant biomarkers and clinical data. Risperidone treatment significantly increased PON1 activity and decreased LOOH levels. These effects of risperidone were not significantly associated with the clinical response and risperidone dosage.

DISCUSSION

Changes in antioxidant profile, but not in lipid or protein oxidation or increased NO production, were found in drug-naive FEP. Risperidone may have antioxidant effects by lowering lipid peroxidation and increasing the antioxidant defenses against lipid peroxidation related to PON1. None of the biomarkers predicted treatment outcome.

Paraoxonase 2 serves a proapopotic function in mouse and human cells in response to the Pseudomonas aeruginosa quorum-sensing molecule N-(3-Oxododecanoyl)-homoserine lactone

Pseudomonas aeruginosa use quorum-sensing molecules, including N-(3-oxododecanoyl)-homoserine lactone (C12), for intercellular communication. C12 activated apoptosis in mouse embryo fibroblasts (MEF) from both wild type (WT) and Bax/Bak double knock-out mice (WT MEF and DKO MEF that were responsive to C12, DKOR MEF): nuclei fragmented; mitochondrial membrane potential (Δψmito) depolarized; Ca(2+) was released from the endoplasmic reticulum (ER), increasing cytosolic [Ca(2+)] (Cacyto); and caspase 3/7 was activated. DKOR MEF had been isolated from a nonclonal pool of DKO MEF that were non-responsive to C12 (DKONR MEF). RNAseq analysis, quantitative PCR, and Western blots showed that WT and DKOR MEF both expressed genes associated with cancer, including paraoxonase 2 (PON2), whereas DKONR MEF expressed little PON2. Adenovirus-mediated expression of human PON2 in DKONR MEF rendered them responsive to C12: Δψmito depolarized, Cacyto increased, and caspase 3/7 activated. Human embryonic kidney 293T (HEK293T) cells expressed low levels of endogenous PON2, and these cells were also less responsive to C12. Overexpression of PON2, but not PON2-H114Q (no lactonase activity) in HEK293T cells caused them to become sensitive to C12. Because [C12] may reach high levels in biofilms in lungs of cystic fibrosis (CF) patients, PON2 lactonase activity may control Δψmito, Ca(2+) release from the ER, and apoptosis in CF airway epithelia. Coupled with previous data, these results also indicate that PON2 uses its lactonase activity to prevent Bax- and Bak-dependent apoptosis in response to common proapoptotic drugs like doxorubicin and staurosporine, but activates Bax- and Bak-independent apoptosis in response to C12.