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Paraoxonase 2 protein is spatially expressed in the human placenta and selectively reduced in labour.

Alwarfaly S, Abdulsid A, Hanretty K, Lyall F - PLoS ONE (2014)

Bottom Line: No difference in protein expression of either isoform was found between the three sites in either the labour or non-labour group.At the middle site there was a highly significant decrease in PON2 expression in the labour group when compared to the non-labour group for both the 62 kDa form (p = 0.02) and the 43 kDa form (p = 0.006).No spatial differences were found within placentas at the mRNA level in either labour or non-labour.

View Article: PubMed Central - PubMed

Affiliation: Institute of Medical Genetics, University of Glasgow School of Medicine, Yorkhill Hospital, Glasgow, United Kingdom.

ABSTRACT
Humans parturition involves interaction of hormonal, neurological, mechanical stretch and inflammatory pathways and the placenta plays a crucial role. The paraoxonases (PONs 1-3) protect against oxidative damage and lipid peroxidation, modulation of endoplasmic reticulum stress and regulation of apoptosis. Nothing is known about the role of PON2 in the placenta and labour. Since PON2 plays a role in oxidative stress and inflammation, both features of labour, we hypothesised that placental PON2 expression would alter during labour. PON2 was examined in placentas obtained from women who delivered by cesarean section and were not in labour and compared to the equivalent zone of placentas obtained from women who delivered vaginally following an uncomplicated labour. Samples were obtained from 12 sites within each placenta: 4 equally spaced apart pieces were sampled from the inner, middle and outer placental regions. PON2 expression was investigated by Western blotting and real time PCR. Two PON2 forms, one at 62 kDa and one at 43 kDa were found in all samples. No difference in protein expression of either isoform was found between the three sites in either the labour or non-labour group. At the middle site there was a highly significant decrease in PON2 expression in the labour group when compared to the non-labour group for both the 62 kDa form (p = 0.02) and the 43 kDa form (p = 0.006). No spatial differences were found within placentas at the mRNA level in either labour or non-labour. There was, paradoxically, an increase in PON2 mRNA in the labour group at the middle site only. This is the first report to describe changes in PON2 in the placenta in labour. The physiological and pathological significance of these remains to be elucidated but since PON2 is anti-inflammatory further studies are warranted to understand its role.

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Related in: MedlinePlus

Western blots showing PON2 expression in inner, middle and outer zones of three individual placentas (non-labour group).Four quadrants were sampled in each zone. A, B and C show the 62Figure 1. D, E and F show the 43 kDa isoform 2 for the 3 placentas also shown in Figure 1.
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pone-0096754-g001: Western blots showing PON2 expression in inner, middle and outer zones of three individual placentas (non-labour group).Four quadrants were sampled in each zone. A, B and C show the 62Figure 1. D, E and F show the 43 kDa isoform 2 for the 3 placentas also shown in Figure 1.

Mentions: This experiment was designed to test if there was a spatial difference in expression of PON2 within individual placentas obtained from women who were not in labour. Two main bands were detected in all placenta samples, one at 62 kDa and one at 43 kDa. These are named as isoform 1 62 kDa and isoform 43 kDa throughout. Examples of Western blots showing PON2 (isoform 1, 62 kDa) expression for 3 different placentas (all non-labour) are shown in Figure 1 (blots A-C). Examples of Western blots showing PON2 (isoform 2, 43 kDa) expression for the same three placentas are also shown in Figure 1 (blots D–F). Friedman test analysis showed there was no difference in expression of either isoform between the three sites (inner, middle, outer) within individual placentas. The graphs for blots A–C (isoform 1, 62 kDa) are shown in Figure 2 (A–C) and the graphs for blots D–F (isoform 2, 43 kDa) are shown in Figure 2 (D–F).


Paraoxonase 2 protein is spatially expressed in the human placenta and selectively reduced in labour.

Alwarfaly S, Abdulsid A, Hanretty K, Lyall F - PLoS ONE (2014)

Western blots showing PON2 expression in inner, middle and outer zones of three individual placentas (non-labour group).Four quadrants were sampled in each zone. A, B and C show the 62Figure 1. D, E and F show the 43 kDa isoform 2 for the 3 placentas also shown in Figure 1.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4016019&req=5

pone-0096754-g001: Western blots showing PON2 expression in inner, middle and outer zones of three individual placentas (non-labour group).Four quadrants were sampled in each zone. A, B and C show the 62Figure 1. D, E and F show the 43 kDa isoform 2 for the 3 placentas also shown in Figure 1.
Mentions: This experiment was designed to test if there was a spatial difference in expression of PON2 within individual placentas obtained from women who were not in labour. Two main bands were detected in all placenta samples, one at 62 kDa and one at 43 kDa. These are named as isoform 1 62 kDa and isoform 43 kDa throughout. Examples of Western blots showing PON2 (isoform 1, 62 kDa) expression for 3 different placentas (all non-labour) are shown in Figure 1 (blots A-C). Examples of Western blots showing PON2 (isoform 2, 43 kDa) expression for the same three placentas are also shown in Figure 1 (blots D–F). Friedman test analysis showed there was no difference in expression of either isoform between the three sites (inner, middle, outer) within individual placentas. The graphs for blots A–C (isoform 1, 62 kDa) are shown in Figure 2 (A–C) and the graphs for blots D–F (isoform 2, 43 kDa) are shown in Figure 2 (D–F).

Bottom Line: No difference in protein expression of either isoform was found between the three sites in either the labour or non-labour group.At the middle site there was a highly significant decrease in PON2 expression in the labour group when compared to the non-labour group for both the 62 kDa form (p = 0.02) and the 43 kDa form (p = 0.006).No spatial differences were found within placentas at the mRNA level in either labour or non-labour.

View Article: PubMed Central - PubMed

Affiliation: Institute of Medical Genetics, University of Glasgow School of Medicine, Yorkhill Hospital, Glasgow, United Kingdom.

ABSTRACT
Humans parturition involves interaction of hormonal, neurological, mechanical stretch and inflammatory pathways and the placenta plays a crucial role. The paraoxonases (PONs 1-3) protect against oxidative damage and lipid peroxidation, modulation of endoplasmic reticulum stress and regulation of apoptosis. Nothing is known about the role of PON2 in the placenta and labour. Since PON2 plays a role in oxidative stress and inflammation, both features of labour, we hypothesised that placental PON2 expression would alter during labour. PON2 was examined in placentas obtained from women who delivered by cesarean section and were not in labour and compared to the equivalent zone of placentas obtained from women who delivered vaginally following an uncomplicated labour. Samples were obtained from 12 sites within each placenta: 4 equally spaced apart pieces were sampled from the inner, middle and outer placental regions. PON2 expression was investigated by Western blotting and real time PCR. Two PON2 forms, one at 62 kDa and one at 43 kDa were found in all samples. No difference in protein expression of either isoform was found between the three sites in either the labour or non-labour group. At the middle site there was a highly significant decrease in PON2 expression in the labour group when compared to the non-labour group for both the 62 kDa form (p = 0.02) and the 43 kDa form (p = 0.006). No spatial differences were found within placentas at the mRNA level in either labour or non-labour. There was, paradoxically, an increase in PON2 mRNA in the labour group at the middle site only. This is the first report to describe changes in PON2 in the placenta in labour. The physiological and pathological significance of these remains to be elucidated but since PON2 is anti-inflammatory further studies are warranted to understand its role.

Show MeSH
Related in: MedlinePlus