Immunohistochemical analysis of paraoxonases-1, 2, and 3 expression in normal mouse tissues.
ABSTRACT The paraoxonase (PON) enzyme family, comprising PON1, PON2, and PON3, are antioxidant enzymes that degrade oxidised phospholipids. We describe the immunohistochemical localisation of the PON proteins in the normal mouse. Antibodies were obtained by inoculating rabbits with peptides derived from specific sequences of mature PONs. PON1 and PON3 were detected in the skin external epithelium, acini of the sebaceous glands, tongue epithelium, acini of the submandibular gland, surface epithelia of the stomach and the intestine, hepatocytes, exocrine pancreas acini, fibre tracts of the encephalon and the spinal cord, skeletal and cardiac muscle, eye lens epithelium and retinal layers, adipocytes, chondrocytes, epithelial cells of the trachea and bronchiole, ovary follicular fluid, seminiferous tubules, spermatozoa, and kidney proximal tubules. PON2 expression was weaker than that of PON1 and PON3, and was absent in some of the tissues studied, such as submandibular gland, nerve cells, and adipocytes. In muscle cells, PON2 expression was restricted to the endomysium. Apolipoprotein A-I did not colocalise with PONs, suggesting local synthesis. This study provides an experimental model to investigate the role played by these enzymes as antioxidants and their relationship with the development of a variety of diseases.
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ABSTRACT: This study revealed and characterised the presence of the antioxidant enzymes paraoxonase (PON) type 1 (PON-1, extracellular) and type 2 (PON-2, intracellular) in boar semen. To evaluate PON-1, an entire ejaculate from each of ten boars was collected and the seminal plasma was harvested after double centrifugation (1,500g for 10 min). Seminal plasma was analysed for concentration as well as enzymatic activity of PON-1 and total cholesterol levels. Seminal-plasma PON-1 concentration ranged from 0.961 to 1.670 ng/ml while its enzymatic activity ranged from 0.056 to 0.400 IU/ml, which represent individual variance. Seminal-plasma PON-1 concentration and enzymatic activity were negatively correlated (r = −0.763; P < 0.01). The activity of seminal-plasma PON-1 negatively correlated with ejaculate volume (r = −0.726, P < 0.05), but positively correlated with sperm concentration (r = 0.654, P < 0.05). Total seminal-plasma cholesterol concentration positively correlated with PON-1 activity (r = 0.773; P < 0.01), but negatively correlated with PON-1 concentration (r = −0.709; P < 0.05). The presence of intracellular PON-2 was determined via immunocytochemistry in spermatozoa derived from artificial insemination. PON-2 localised to the post-acrosomal area of the sperm head and principal piece of the tail in membrane-intact spermatozoa. In summary, PON is present in boar semen, with PON-1 at low levels in seminal plasma and PON-2 within the spermatozoa. Further studies are needed to characterise the relationship between antioxidant PONs with sperm and other seminal-plasma parameters. Mol. Reprod. Dev. 2014. © 2014 Wiley Periodicals, Inc.Molecular Reproduction and Development 12/2014; 82(1). DOI:10.1002/mrd.22444 · 2.68 Impact Factor
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ABSTRACT: Homocysteine (Hcy) is a risk factor for Alzheimer's disease (AD). Paraoxonase 1 (Pon1) participates in Hcy metabolism and is also linked to AD. The inactivation of the Pon1 gene in mice causes the accumulation of Hcy-thiolactone in the brain and increases the susceptibility to Hcy-thiolactone-induced seizures. To gain insight into the brain-related Pon1 function, we used two-dimensional IEF/SDS-PAGE gel electrophoresis and MALDI-TOF/TOF mass spectrometry to study brain proteomes of Pon1-/- and Pon1+/+ mice fed with a hyperhomocysteinemic high-methionine (Met) or a control diet. We found that: 1) proteins involved in brain-specific function (Nrgn), antioxidant defenses (Sod1, DJ-1), and cytoskeleton assembly (Tbcb, CapZa2) were differentially expressed in brains of Pon1-null mice; 2) proteins involved in brain-specific function (Ncald, Nrgn, Stmn1), antioxidant defenses (Prdx2, DJ-1), energy metabolism (Ak1), cell cycle (GDI1, Ran), cytoskeleton assembly (Tbcb), and unknown function (Hdhd2) showed differential expression in brains of Pon1-null fed with a hyperhomocysteinemic high-Met diet; 3) most proteins regulated by the Pon1-/- genotype were also regulated by the high-Met diet; 4) the proteins differentially expressed in Pon1-null mouse brains play important roles in neural development, learning, plasticity, and aging and are linked to neurodegenerative diseases, including AD. Taken together, our findings suggest that Pon1 interacts with diverse cellular processes from energy metabolism and anti-oxidative defenses to cell cycle, cytoskeleton dynamics, and synaptic plasticity essential for normal brain homeostasis and that these interactions are modulated by hyperhomocysteinemia and account for the involvement of Hcy and Pon1 in AD.Journal of Alzheimer's disease: JAD 05/2014; 42(1). DOI:10.3233/JAD-132714 · 3.61 Impact Factor
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ABSTRACT: To investigate the relationships between serum paraoxonase-1 (PON1), insulin resistance, and metabolic syndrome (MetS) in childhood obesity. We studied 110 obese children and 36 non-obese children with a similar gender and age distribution. We measured serum PON1 activity against 5-thiobutyl butyrolactone (TBBLase) and against paraoxon (paraoxonase). PON1 concentration was measured separately as were the levels of several standard metabolic variables. The homeostasis model assessment (HOMA) index was calculated as an estimate of insulin resistance. TBBLase was significantly decreased in obese children (P=0.008), while paraoxonase activity and PON1 concentrations showed non-significant trends towards decrease and increase, respectively (P=0.054 and P=0.060). TBBLase and paraoxonase specific activities were significantly decreased (P=0.004 and P=0.018, respectively). TBBLase specific activity was inversely associated with BMI, percentage body fat, insulin, HOMA, triglycerides, and C-reactive protein, and directly associated with HDL-cholesterol. Paraoxonase specific activity showed similar associations with BMI, percentage fat, HDL-cholesterol, and C-reactive protein. Obese children with MetS had lower TBBLase activities than obese children without MetS (P=0.018). Linear regression analyses showed that TBBLase was independently associated with HDL-cholesterol, BMI, percentage body fat and PON155 polymorphism, but paraoxonase activity was associated only with PON1192 polymorphism. Our results suggest that PON1 may play a role in the onset and development of metabolic alterations in childhood obesity leading to diabetes and cardiovascular disease later in life. However, being derived from statistical association study, this finding cannot be seen as showing cause-effect.Clinical biochemistry 09/2013; 46(18). DOI:10.1016/j.clinbiochem.2013.08.020 · 2.23 Impact Factor