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Vasoinhibins regulate the inner and outer blood-retinal barrier and limit retinal oxidative stress.

Arredondo Zamarripa D, Díaz-Lezama N, Meléndez García R, Chávez Balderas J, Adán N, Ledesma-Colunga MG, Arnold E, Clapp C, Thebault S - Front Cell Neurosci (2014)

Bottom Line: BK transiently decreased human RPE (ARPE-19) cell monolayer resistance, and this effect was blocked by vasoinhibins, L-NAME, and NAC.DETANONOate reverted the blocking effect of vasoinhibins.These effects on RPE resistance coincided with actin cytoskeleton redistribution.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México.

ABSTRACT
Vasoinhibins are prolactin fragments present in the retina, where they have been shown to prevent the hypervasopermeability associated with diabetes. Enhanced bradykinin (BK) production contributes to the increased transport through the blood-retina barrier (BRB) in diabetes. Here, we studied if vasoinhibins regulate BRB permeability by targeting the vascular endothelium and retinal pigment epithelium (RPE) components of this barrier. Intravitreal injection of BK in male rats increased BRB permeability. Vasoinhibins prevented this effect, as did the B2 receptor antagonist Hoe-140. BK induced a transient decrease in mouse retinal and brain capillary endothelial monolayer resistance that was blocked by vasoinhibins. Both vasoinhibins and the nitric oxide (NO) synthase inhibitor L-NAME, but not the antioxidant N-acetyl cysteine (NAC), blocked the transient decrease in bovine umbilical vein endothelial cell (BUVEC) monolayer resistance induced by BK; this block was reversed by the NO donor DETANONOate. Vasoinhibins also prevented the BK-induced actin cytoskeleton redistribution, as did L-NAME. BK transiently decreased human RPE (ARPE-19) cell monolayer resistance, and this effect was blocked by vasoinhibins, L-NAME, and NAC. DETANONOate reverted the blocking effect of vasoinhibins. Similar to BK, the radical initiator Luperox induced a reduction in ARPE-19 cell monolayer resistance, which was prevented by vasoinhibins. These effects on RPE resistance coincided with actin cytoskeleton redistribution. Intravitreal injection of vasoinhibins reduced the levels of reactive oxygen species (ROS) in retinas of streptozotocin-induced diabetic rats, particularly in the RPE and capillary-containing layers. Thus, vasoinhibins reduce BRB permeability by targeting both its main inner and outer components through NO- and ROS-dependent pathways, offering potential treatment strategies against diabetic retinopathies.

No MeSH data available.


Related in: MedlinePlus

Vasoinhibins reduce the retinal levels of ROS in streptozotocin-induced diabetic rats. (A) Representative images of superoxide anion production stained with dihydroethidium (DHE) on retina sections from control (Ctl) rats intravitreously injected with PBS or vasoinhibins (Vi, 1 μM) for 24 h and from streptozotocin (STZ)-induced diabetic rats intravitreously injected with PBS or Vi 24 h before the end of the 4 weeks of diabetes. Scale bar is 100 μm. (B) Fluorescence intensity of superoxide anion quantified as mean number of pixels positive for DHE staining normalized to the mean number of pixels positive for DAPI staining in the retinal pigment epithelium (RPE), outer nuclear (ONL), inner nuclear (INL), inner plexiform (IPL), and ganglion cell (GCL) layers. Data are mean ± s.e.m. of values obtained from 3 rats in each group. *P < 0.05. NS, not significant.
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Figure 7: Vasoinhibins reduce the retinal levels of ROS in streptozotocin-induced diabetic rats. (A) Representative images of superoxide anion production stained with dihydroethidium (DHE) on retina sections from control (Ctl) rats intravitreously injected with PBS or vasoinhibins (Vi, 1 μM) for 24 h and from streptozotocin (STZ)-induced diabetic rats intravitreously injected with PBS or Vi 24 h before the end of the 4 weeks of diabetes. Scale bar is 100 μm. (B) Fluorescence intensity of superoxide anion quantified as mean number of pixels positive for DHE staining normalized to the mean number of pixels positive for DAPI staining in the retinal pigment epithelium (RPE), outer nuclear (ONL), inner nuclear (INL), inner plexiform (IPL), and ganglion cell (GCL) layers. Data are mean ± s.e.m. of values obtained from 3 rats in each group. *P < 0.05. NS, not significant.

Mentions: To assess the physiological relevance of our findings, we analyzed the production of superoxide anion in retinas of rats that were rendered diabetic (Pouliot et al., 2012). Figure 7A shows representative images of retinas stained with the oxidative fluorescent dye DHE (red) and the DNA stain DAPI (blue), and quantification using the mean pixel fluorescence intensity ratio of DHE/DAPI for each nuclear layer of the retina is provided in Figure 7B. In all conditions, the outer segments of photoreceptors were positive for DHE staining due to non-specific autofluorescence (Ling-Ling Zhao et al., 2009). In non-diabetic retinas, the RPE produced more superoxide anion than other layers (shown with an arrow head). After 4 weeks of diabetes, superoxide anion production was enhanced in the RPE (indicated with arrow heads in micrograph), outer nuclear and ganglion cell layers (indicated with asterisks in micrograph), as previously reported (Pouliot et al., 2011). Intravitreal injection of vasoinhibins abolished the diabetes effect on levels of superoxide anions in the RPE and the three nuclear layers of the retina. Alone, vasoinhibins had no effect on basal production of superoxide anions in the retina.


Vasoinhibins regulate the inner and outer blood-retinal barrier and limit retinal oxidative stress.

Arredondo Zamarripa D, Díaz-Lezama N, Meléndez García R, Chávez Balderas J, Adán N, Ledesma-Colunga MG, Arnold E, Clapp C, Thebault S - Front Cell Neurosci (2014)

Vasoinhibins reduce the retinal levels of ROS in streptozotocin-induced diabetic rats. (A) Representative images of superoxide anion production stained with dihydroethidium (DHE) on retina sections from control (Ctl) rats intravitreously injected with PBS or vasoinhibins (Vi, 1 μM) for 24 h and from streptozotocin (STZ)-induced diabetic rats intravitreously injected with PBS or Vi 24 h before the end of the 4 weeks of diabetes. Scale bar is 100 μm. (B) Fluorescence intensity of superoxide anion quantified as mean number of pixels positive for DHE staining normalized to the mean number of pixels positive for DAPI staining in the retinal pigment epithelium (RPE), outer nuclear (ONL), inner nuclear (INL), inner plexiform (IPL), and ganglion cell (GCL) layers. Data are mean ± s.e.m. of values obtained from 3 rats in each group. *P < 0.05. NS, not significant.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4202700&req=5

Figure 7: Vasoinhibins reduce the retinal levels of ROS in streptozotocin-induced diabetic rats. (A) Representative images of superoxide anion production stained with dihydroethidium (DHE) on retina sections from control (Ctl) rats intravitreously injected with PBS or vasoinhibins (Vi, 1 μM) for 24 h and from streptozotocin (STZ)-induced diabetic rats intravitreously injected with PBS or Vi 24 h before the end of the 4 weeks of diabetes. Scale bar is 100 μm. (B) Fluorescence intensity of superoxide anion quantified as mean number of pixels positive for DHE staining normalized to the mean number of pixels positive for DAPI staining in the retinal pigment epithelium (RPE), outer nuclear (ONL), inner nuclear (INL), inner plexiform (IPL), and ganglion cell (GCL) layers. Data are mean ± s.e.m. of values obtained from 3 rats in each group. *P < 0.05. NS, not significant.
Mentions: To assess the physiological relevance of our findings, we analyzed the production of superoxide anion in retinas of rats that were rendered diabetic (Pouliot et al., 2012). Figure 7A shows representative images of retinas stained with the oxidative fluorescent dye DHE (red) and the DNA stain DAPI (blue), and quantification using the mean pixel fluorescence intensity ratio of DHE/DAPI for each nuclear layer of the retina is provided in Figure 7B. In all conditions, the outer segments of photoreceptors were positive for DHE staining due to non-specific autofluorescence (Ling-Ling Zhao et al., 2009). In non-diabetic retinas, the RPE produced more superoxide anion than other layers (shown with an arrow head). After 4 weeks of diabetes, superoxide anion production was enhanced in the RPE (indicated with arrow heads in micrograph), outer nuclear and ganglion cell layers (indicated with asterisks in micrograph), as previously reported (Pouliot et al., 2011). Intravitreal injection of vasoinhibins abolished the diabetes effect on levels of superoxide anions in the RPE and the three nuclear layers of the retina. Alone, vasoinhibins had no effect on basal production of superoxide anions in the retina.

Bottom Line: BK transiently decreased human RPE (ARPE-19) cell monolayer resistance, and this effect was blocked by vasoinhibins, L-NAME, and NAC.DETANONOate reverted the blocking effect of vasoinhibins.These effects on RPE resistance coincided with actin cytoskeleton redistribution.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México.

ABSTRACT
Vasoinhibins are prolactin fragments present in the retina, where they have been shown to prevent the hypervasopermeability associated with diabetes. Enhanced bradykinin (BK) production contributes to the increased transport through the blood-retina barrier (BRB) in diabetes. Here, we studied if vasoinhibins regulate BRB permeability by targeting the vascular endothelium and retinal pigment epithelium (RPE) components of this barrier. Intravitreal injection of BK in male rats increased BRB permeability. Vasoinhibins prevented this effect, as did the B2 receptor antagonist Hoe-140. BK induced a transient decrease in mouse retinal and brain capillary endothelial monolayer resistance that was blocked by vasoinhibins. Both vasoinhibins and the nitric oxide (NO) synthase inhibitor L-NAME, but not the antioxidant N-acetyl cysteine (NAC), blocked the transient decrease in bovine umbilical vein endothelial cell (BUVEC) monolayer resistance induced by BK; this block was reversed by the NO donor DETANONOate. Vasoinhibins also prevented the BK-induced actin cytoskeleton redistribution, as did L-NAME. BK transiently decreased human RPE (ARPE-19) cell monolayer resistance, and this effect was blocked by vasoinhibins, L-NAME, and NAC. DETANONOate reverted the blocking effect of vasoinhibins. Similar to BK, the radical initiator Luperox induced a reduction in ARPE-19 cell monolayer resistance, which was prevented by vasoinhibins. These effects on RPE resistance coincided with actin cytoskeleton redistribution. Intravitreal injection of vasoinhibins reduced the levels of reactive oxygen species (ROS) in retinas of streptozotocin-induced diabetic rats, particularly in the RPE and capillary-containing layers. Thus, vasoinhibins reduce BRB permeability by targeting both its main inner and outer components through NO- and ROS-dependent pathways, offering potential treatment strategies against diabetic retinopathies.

No MeSH data available.


Related in: MedlinePlus