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Parkinson's disease (PD) is an oxidative stress-mediated neurodegenerative disorder caused by selective dopaminergic neuronal death in the midbrain substantia nigra. Paraoxonase 1 (PON1) is a potent inhibitor of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) against oxidation by destroying biologically active phospholipids with potential protective effects against oxidative stress-induced inflammatory disorders. In a previous study, we constructed protein transduction domain (PTD) fusion PEP-1-PON1 protein to transduce PON1 into cells and tissue. In this study, we examined the role of transduced PEP-1-PON1 protein in repressing oxidative stress-mediated inflammatory response in microglial BV2 cells after exposure to lipopolysaccharide (LPS). Moreover, we identified the functions of transduced PEP-1-PON1 proteins which include, mitigating mitochondrial damage, decreasing reactive oxidative species (ROS) production, matrix metalloproteinase-9 (MMP-9) expression and protecting against 1-methyl-4-phenylpyridinium (MPP(+))-induced neurotoxicity in SH-SY5Y cells. Furthermore, transduced PEP-1-PON1 protein reduced MMP-9 expression and protected against dopaminergic neuronal cell death in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice model. Taken together, these results suggest a promising therapeutic application of PEP-1-PON1 proteins against PD and other inflammation and oxidative stress-related neuronal diseases., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Objective: To observe the effect on the inhibition of coronary atherosclerosis hardening of the paraoxonase gene (PON-1) which transfected to the rabbit epicardial adipose tissue., Methods: Rabbit coronary atherosclerosis model was established by high-fat feeding, liposome-encapsulated recombinant plasmid pEGFP-PON-1 50 μ L was injected to the rabbit pericardial cavity, and was harvested 4 weeks after transfection., Results: The epicardial fat transfected PON-1 gene had effect on the high lipid level. It significantly increased expression of PON-1 in peripheral arterial vascular tissue (P <0.05); and significantly reduced total cholesterol and low-density lipoprotein cholesterol levels (P<0.05), and the thickness ratio of coronary artery intima/media (P <0.05)., Conclusions: The injection of the PON-1 gene in the pericardial cavity can effectively suppress the formation of coronary atherosclerosis., (Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.)

Human paraoxonase-1 (HuPON1) has been proposed as a catalytic bioscavenger of organophosphorus (OP) pesticides and nerve agents. We assessed the potential of this enzyme to protect against OP poisoning using two different paradigms. First, recombinant HuPON1 purified from cabbage loopers (iPON1; Trichoplusia ni) was administered to guinea pigs, followed by exposure to at least 2 times the median lethal dose (LD(50)) of the OP nerve agents tabun (GA), sarin (GB), soman (GD), and cyclosarin (GF), or chlorpyrifos oxon, the toxic metabolite of the OP pesticide chlorpyrifos. In the second model, mice were infected with an adenovirus that induced expression of HuPON1 and then exposed to sequential doses of GD, VX, or (as reported previously) diazoxon, the toxic metabolite of the OP pesticide diazinon. In both animal models, the exogenously added HuPON1 protected animals against otherwise lethal doses of the OP pesticides but not against the nerve agents. Together, the results support prior modeling and in vitro activity data which suggest that wild-type HuPON1 does not have sufficient catalytic activity to provide in vivo protection against nerve agents., (Published by Elsevier Ireland Ltd.)

Background: Serum paraoxonase (PON1) is a high density lipoprotein (HDL)-associated enzyme involved in organophosphate (OP) degradation and prevention of atherosclerosis. PON1 comprises a potential candidate for in vivo therapeutics, as an anti-atherogenic agent, and for detoxification of pesticides and nerve agents. Because human PON1 exhibits limited stability, engineered, recombinant PON1 (rePON1) variants that were designed for higher reactivity, solubility, stability, and bacterial expression, are candidates for treatment. This work addresses the feasibility of in vivo administration of rePON1, and its HDL complex, as a potentially therapeutic agent dubbed BL-3050., Methods: For stability studies we applied different challenges related to the in vivo disfunctionalization of HDL and PON1 and tested for inactivation of PON1's activity. We applied acute, repetitive administrations of BL-3050 in mice to assess its toxicity and adverse immune responses. The in vivo efficacy of recombinant PON1 and BL-3050 were tested with an animal model of chlorpyrifos-oxon poisoning., Results: Inactivation studies show significantly improved in vitro lifespan of the engineered rePON1 relative to human PON1. Significant sequence changes relative to human PON1 might hamper the in vivo applicability of BL-3050 due to adverse immune responses. However, we observed no toxic effects in mice subjected to repetitive administration of BL-3050, suggesting that BL-3050 could be safely used. To further evaluate the activity of BL-3050 in vivo, we applied an animal model that mimics human organophosphate poisoning. In these studies, a significant advantages of rePON1 and BL-3050 (>87.5% survival versus <37.5% in the control groups) was observed. Furthermore, BL-3050 and rePON1 were superior to the conventional treatment of atropine-2-PAM as a prophylactic treatment for OP poisoning., Conclusion: In vitro and in vivo data described here demonstrate the potential advantages of rePON1 and BL-3050 for treatment of OP toxicity and chronic cardiovascular diseases like atherosclerosis. The in vivo data also suggest that rePON1 and BL-3050 are stable and safe, and could be used for acute, and possibly repeated treatments, with no adverse effects.

Objective: The purpose of this study was to analyze the consequences of HDL oxidation for paraoxonase-1 metabolism and function., Methods and Results: HDL was oxidized with AAPH, copper ions, and hypochlorite. Secretion studies were performed using human paraoxonase-1-transfected cells lines and primary rat hepatocytes. Stability studies were performed with recombinant paraoxonase. Conditioned medium had significantly reduced paraoxonase-1 when Cu or AAPH-oxidized HDL was the acceptor complex (P<0.01); reduction was dose-dependent on the degree of oxidation. Oxidized HDL had a reduced capacity to stabilize/improve activity of secreted paraoxonase-1. Reduced secretion could not be attributed to enzyme inactivation by lipoperoxides, reduced binding affinity of HDL, or oxidation of the lipid component alone. Hypochlorite oxidation of HDL did not modify HDL-mediated paraoxonase-1 release, but activity of HDL-associated paraoxonase-1 was particularly sensitive to such treatment., Conclusions: AAPH and copper, but not hypochlorite, oxidation of HDL compromises its ability to promote release of paraoxonase-1 and stabilize enzyme activity. HDL-associated paraoxonase-1 is highly sensitive to hypochlorite. Reducing paraoxonase-1 renders HDL susceptible to oxidation, which may compromise HDL function. It provides a novel example at the HDL level of the detrimental effects of oxidative stress, and underlines the need for further evaluation of the consequences of HDL oxidation.