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Smooth muscle specific overexpression of p22phox potentiates carotid artery wall thickening in response to injury.

Manogue MR, Bennett JR, Holland DS, Choi CS, Drake DA, Taylor MS, Weber DS - Oxid Med Cell Longev (2015)

Bottom Line: To examine the role of reactive oxygen species (ROS) as a mediator of vascular injury, the injury response was quantified by measuring wall thickness (WT) and cross-sectional wall area (CSWA) of the injured and noninjured arteries in both Tg(p22smc) and wild-type animals at days 3, 7, and 14 after injury.Akt, p38 MAPK, and Src activation were evaluated at the same time points using Western blotting.Both increased activation and temporal regulation of these signaling pathways may contribute to enhanced vascular growth in response to injury in this transgenic model of elevated vascular ROS.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, University of South Alabama, Mobile, AL 36688, USA.

ABSTRACT
We hypothesized that transgenic mice overexpressing the p22(phox) subunit of the NADPH oxidase selectively in smooth muscle (Tg(p22smc)) would exhibit an exacerbated response to transluminal carotid injury compared to wild-type mice. To examine the role of reactive oxygen species (ROS) as a mediator of vascular injury, the injury response was quantified by measuring wall thickness (WT) and cross-sectional wall area (CSWA) of the injured and noninjured arteries in both Tg(p22smc) and wild-type animals at days 3, 7, and 14 after injury. Akt, p38 MAPK, and Src activation were evaluated at the same time points using Western blotting. WT and CSWA following injury were significantly greater in Tg(p22smc) mice at both 7 and 14 days after injury while noninjured contralateral carotids were similar between groups. Apocynin treatment attenuated the injury response in both groups and rendered the response similar between Tg(p22smc) mice and wild-type mice. Following injury, carotid arteries from Tg(p22smc) mice demonstrated elevated activation of Akt at day 3, while p38 MAPK and Src activation was elevated at day 7 compared to wild-type mice. Both increased activation and temporal regulation of these signaling pathways may contribute to enhanced vascular growth in response to injury in this transgenic model of elevated vascular ROS.

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(a) Hematoxylin and eosin stained cross sections of carotid arteries harvested at selected time points following injury in C57BL/6J and Tgp22smc mice. Representative sections from noninjured arteries ((A) and (B)) and carotid arteries 3 days after injury ((C) and (D)), 7 days after injury ((E) and (F)), and 14 days after injury ((G) and (H)) are shown. (b) Representative luminal images of fluo-4 treated sections of isolated carotid artery segments from a noninjured artery and injured arteries at days 0, 7, and 14 days following vascular injury. All images were obtained at a magnification of 200x and the scale bar is equal to 20 μm.
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fig1: (a) Hematoxylin and eosin stained cross sections of carotid arteries harvested at selected time points following injury in C57BL/6J and Tgp22smc mice. Representative sections from noninjured arteries ((A) and (B)) and carotid arteries 3 days after injury ((C) and (D)), 7 days after injury ((E) and (F)), and 14 days after injury ((G) and (H)) are shown. (b) Representative luminal images of fluo-4 treated sections of isolated carotid artery segments from a noninjured artery and injured arteries at days 0, 7, and 14 days following vascular injury. All images were obtained at a magnification of 200x and the scale bar is equal to 20 μm.

Mentions: To determine the vascular response to injury in the presence of increased VSMC ROS, we obtained histological sections of each artery in axial cross section. Hematoxylin and eosin images were used to observe and quantify changes in arterial morphology following wire injury (Figure 1(a)). En face confocal microscopy images were used to confirm successful endothelial removal and establish the subsequent time course of repair following wire-injury. Substantial reendothelialization occurred 14 days following injury (Figure 1(b)) and the endothelium appears fully regenerated 21 days following injury (data not shown). Figure 2(a) reports the cumulative data of wall thickness measurements following carotid injury in both groups of mice. Uninjured arteries in p22phox and wild-type mice showed no significant difference in wall thickness throughout the time course of injury. At 3 days after injury, both Tgp22smc and wild-type groups showed small but significant increases in the mean wall thickness when comparing injured to uninjured arteries, but there was no significant difference in the mean arterial wall thickness between the two injured groups at day 3. At 7 days following injury, both Tgp22smc and wild-type groups showed increased wall thickness when comparing uninjured arteries to injured arteries, but, in contrast to day 3, the difference in wall thickness was significantly greater in Tgp22smc injured vessels than wild-type injured vessels (46.1 ± 2.6 versus 37.1 ± 2.8 μm). At day 14 after injury, both groups of mice demonstrated increased wall thickness, and, similar to day 7, wall thickness was significantly greater in Tgp22smc mice compared to wild-type mice (66.0 ± 10 versus 41.8 ± 2 μm) (Figure 2(a)). Moreover, in addition to demonstrating a significantly larger maximal wall thickness measured at 14 days following injury, the rate of change in wall thickness during the progression of injury was significantly accelerated in the Tgp22smc group (slopes 2.9 ± 0.08, r2 = 1.0 versus 0.95 ± 0.2, r2 = 0.95).


Smooth muscle specific overexpression of p22phox potentiates carotid artery wall thickening in response to injury.

Manogue MR, Bennett JR, Holland DS, Choi CS, Drake DA, Taylor MS, Weber DS - Oxid Med Cell Longev (2015)

(a) Hematoxylin and eosin stained cross sections of carotid arteries harvested at selected time points following injury in C57BL/6J and Tgp22smc mice. Representative sections from noninjured arteries ((A) and (B)) and carotid arteries 3 days after injury ((C) and (D)), 7 days after injury ((E) and (F)), and 14 days after injury ((G) and (H)) are shown. (b) Representative luminal images of fluo-4 treated sections of isolated carotid artery segments from a noninjured artery and injured arteries at days 0, 7, and 14 days following vascular injury. All images were obtained at a magnification of 200x and the scale bar is equal to 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4402189&req=5

fig1: (a) Hematoxylin and eosin stained cross sections of carotid arteries harvested at selected time points following injury in C57BL/6J and Tgp22smc mice. Representative sections from noninjured arteries ((A) and (B)) and carotid arteries 3 days after injury ((C) and (D)), 7 days after injury ((E) and (F)), and 14 days after injury ((G) and (H)) are shown. (b) Representative luminal images of fluo-4 treated sections of isolated carotid artery segments from a noninjured artery and injured arteries at days 0, 7, and 14 days following vascular injury. All images were obtained at a magnification of 200x and the scale bar is equal to 20 μm.
Mentions: To determine the vascular response to injury in the presence of increased VSMC ROS, we obtained histological sections of each artery in axial cross section. Hematoxylin and eosin images were used to observe and quantify changes in arterial morphology following wire injury (Figure 1(a)). En face confocal microscopy images were used to confirm successful endothelial removal and establish the subsequent time course of repair following wire-injury. Substantial reendothelialization occurred 14 days following injury (Figure 1(b)) and the endothelium appears fully regenerated 21 days following injury (data not shown). Figure 2(a) reports the cumulative data of wall thickness measurements following carotid injury in both groups of mice. Uninjured arteries in p22phox and wild-type mice showed no significant difference in wall thickness throughout the time course of injury. At 3 days after injury, both Tgp22smc and wild-type groups showed small but significant increases in the mean wall thickness when comparing injured to uninjured arteries, but there was no significant difference in the mean arterial wall thickness between the two injured groups at day 3. At 7 days following injury, both Tgp22smc and wild-type groups showed increased wall thickness when comparing uninjured arteries to injured arteries, but, in contrast to day 3, the difference in wall thickness was significantly greater in Tgp22smc injured vessels than wild-type injured vessels (46.1 ± 2.6 versus 37.1 ± 2.8 μm). At day 14 after injury, both groups of mice demonstrated increased wall thickness, and, similar to day 7, wall thickness was significantly greater in Tgp22smc mice compared to wild-type mice (66.0 ± 10 versus 41.8 ± 2 μm) (Figure 2(a)). Moreover, in addition to demonstrating a significantly larger maximal wall thickness measured at 14 days following injury, the rate of change in wall thickness during the progression of injury was significantly accelerated in the Tgp22smc group (slopes 2.9 ± 0.08, r2 = 1.0 versus 0.95 ± 0.2, r2 = 0.95).

Bottom Line: To examine the role of reactive oxygen species (ROS) as a mediator of vascular injury, the injury response was quantified by measuring wall thickness (WT) and cross-sectional wall area (CSWA) of the injured and noninjured arteries in both Tg(p22smc) and wild-type animals at days 3, 7, and 14 after injury.Akt, p38 MAPK, and Src activation were evaluated at the same time points using Western blotting.Both increased activation and temporal regulation of these signaling pathways may contribute to enhanced vascular growth in response to injury in this transgenic model of elevated vascular ROS.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, University of South Alabama, Mobile, AL 36688, USA.

ABSTRACT
We hypothesized that transgenic mice overexpressing the p22(phox) subunit of the NADPH oxidase selectively in smooth muscle (Tg(p22smc)) would exhibit an exacerbated response to transluminal carotid injury compared to wild-type mice. To examine the role of reactive oxygen species (ROS) as a mediator of vascular injury, the injury response was quantified by measuring wall thickness (WT) and cross-sectional wall area (CSWA) of the injured and noninjured arteries in both Tg(p22smc) and wild-type animals at days 3, 7, and 14 after injury. Akt, p38 MAPK, and Src activation were evaluated at the same time points using Western blotting. WT and CSWA following injury were significantly greater in Tg(p22smc) mice at both 7 and 14 days after injury while noninjured contralateral carotids were similar between groups. Apocynin treatment attenuated the injury response in both groups and rendered the response similar between Tg(p22smc) mice and wild-type mice. Following injury, carotid arteries from Tg(p22smc) mice demonstrated elevated activation of Akt at day 3, while p38 MAPK and Src activation was elevated at day 7 compared to wild-type mice. Both increased activation and temporal regulation of these signaling pathways may contribute to enhanced vascular growth in response to injury in this transgenic model of elevated vascular ROS.

Show MeSH
Related in: MedlinePlus