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Acute and subchronic exposure to air particulate matter induces expression of angiotensin and bradykinin-related genes in the lungs and heart: Angiotensin-II type-I receptor as a molecular target of particulate matter exposure.

Aztatzi-Aguilar OG, Uribe-Ramírez M, Arias-Montaño JA, Barbier O, De Vizcaya-Ruiz A - Part Fibre Toxicol (2015)

Bottom Line: The PM fractions induced the expression of RAAS and KKS elements in the lungs and heart in a time-dependent manner.The AT1R lung protein showed a time-dependent change in subcellular distribution.In addition, the presence of AT1R in the heart was accompanied by a decrease in HO-1, which was concomitant with the induction of Acta1 and Col3a1 and the increment of IL-6.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Avenida Instituto Politécnico Nacional, 2508, México D. F, CP. 07360, Mexico. gammaztatzi@gmail.com.

ABSTRACT

Background: Particulate matter (PM) adverse effects on health include lung and heart damage. The renin-angiotensin-aldosterone (RAAS) and kallikrein-kinin (KKS) endocrine systems are involved in the pathophysiology of cardiovascular diseases and have been found to impact lung diseases. The aim of the present study was to evaluate whether PM exposure regulates elements of RAAS and KKS.

Methods: Sprague-Dawley rats were acutely (3 days) and subchronically (8 weeks) exposed to coarse (CP), fine (FP) or ultrafine (UFP) particulates using a particulate concentrator, and a control group exposed to filtered air (FA). We evaluated the mRNA of the RAAS components At1, At2r and Ace, and of the KKS components B1r, B2r and Klk-1 by RT-PCR in the lungs and heart. The ACE and AT1R protein were evaluated by Western blot, as were HO-1 and γGCSc as indicators of the antioxidant response and IL-6 levels as an inflammation marker. We performed a binding assay to determinate AT1R density in the lung, also the subcellular AT1R distribution in the lungs was evaluated. Finally, we performed a histological analysis of intramyocardial coronary arteries and the expression of markers of heart gene reprogramming (Acta1 and Col3a1).

Results: The PM fractions induced the expression of RAAS and KKS elements in the lungs and heart in a time-dependent manner. CP exposure induced Ace mRNA expression and regulated its protein in the lungs. Acute and subchronic exposure to FP and UFP induced the expression of At1r in the lungs and heart. All PM fractions increased the AT1R protein in a size-dependent manner in the lungs and heart after subchronic exposure. The AT1R lung protein showed a time-dependent change in subcellular distribution. In addition, the presence of AT1R in the heart was accompanied by a decrease in HO-1, which was concomitant with the induction of Acta1 and Col3a1 and the increment of IL-6. Moreover, exposure to all PM fractions increased coronary artery wall thickness.

Conclusion: We demonstrate that exposure to PM induces the expression of RAAS and KKS elements, including AT1R, which was the main target in the lungs and the heart.

No MeSH data available.


Related in: MedlinePlus

Acute exposure to PM modifies [3H]-Angiotensin-II binding to the lung tissue membranes. a) Saturation binding. Membranes, obtained from naïve animals as described in Methods, were incubated with the indicated concentrations of [3H]-Angiotensin-II. Specific receptor binding was determined by subtracting the binding in the presence of 100 μM telmisartan from the total binding. The points show the means from quadruplicate determinations from a single experiment, which was repeated twice more with membranes obtained from different naïve animals. The line drawn is the best fit to a hyperbola. Best-fit values for the equilibrium dissociation constant (Kd) and maximum binding (Bmax) are given in the text. b) Single-point determinations. Membranes were obtained from animals exposed to coarse (CP), fine (FP) and ultrafine particulate (UFP) or from the filtered air control group (FA), and then incubated with 10 nM [3H]-Angiotensin-II. Specific receptor binding was determined by subtracting the binding in the presence of 10 μM telmisartan. Scatter dot plot shows the value of the median. * Indicates significant differences among groups (n = 4 per group, p < 0.05)
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Fig3: Acute exposure to PM modifies [3H]-Angiotensin-II binding to the lung tissue membranes. a) Saturation binding. Membranes, obtained from naïve animals as described in Methods, were incubated with the indicated concentrations of [3H]-Angiotensin-II. Specific receptor binding was determined by subtracting the binding in the presence of 100 μM telmisartan from the total binding. The points show the means from quadruplicate determinations from a single experiment, which was repeated twice more with membranes obtained from different naïve animals. The line drawn is the best fit to a hyperbola. Best-fit values for the equilibrium dissociation constant (Kd) and maximum binding (Bmax) are given in the text. b) Single-point determinations. Membranes were obtained from animals exposed to coarse (CP), fine (FP) and ultrafine particulate (UFP) or from the filtered air control group (FA), and then incubated with 10 nM [3H]-Angiotensin-II. Specific receptor binding was determined by subtracting the binding in the presence of 10 μM telmisartan. Scatter dot plot shows the value of the median. * Indicates significant differences among groups (n = 4 per group, p < 0.05)

Mentions: Similar to other G protein-coupled receptors, upon activation AT1Rs can be internalized from the cell membrane to the cytoplasm and then can be either recycled or degraded. Because the reduction in AT1R protein after the acute exposure to FP and UFP did not match the mRNA levels, we performed a binding assay with labeled Ang-II as an alternative method to confirm the protein levels. First, we obtained a saturation curve to determine the receptor density and the affinity for [3H]-Angiotensin-II in lung membranes obtained from rats that were not used in the PM experiments. These determinations (Fig. 3a) yielded a maximum specific binding (Bmax) of 90 ± 10 fmol/mg protein (3 experiments) and an equilibrium dissociation constant (Kd) of 2.8 nM (pKd 17.2 ± 7.7).Fig. 3


Acute and subchronic exposure to air particulate matter induces expression of angiotensin and bradykinin-related genes in the lungs and heart: Angiotensin-II type-I receptor as a molecular target of particulate matter exposure.

Aztatzi-Aguilar OG, Uribe-Ramírez M, Arias-Montaño JA, Barbier O, De Vizcaya-Ruiz A - Part Fibre Toxicol (2015)

Acute exposure to PM modifies [3H]-Angiotensin-II binding to the lung tissue membranes. a) Saturation binding. Membranes, obtained from naïve animals as described in Methods, were incubated with the indicated concentrations of [3H]-Angiotensin-II. Specific receptor binding was determined by subtracting the binding in the presence of 100 μM telmisartan from the total binding. The points show the means from quadruplicate determinations from a single experiment, which was repeated twice more with membranes obtained from different naïve animals. The line drawn is the best fit to a hyperbola. Best-fit values for the equilibrium dissociation constant (Kd) and maximum binding (Bmax) are given in the text. b) Single-point determinations. Membranes were obtained from animals exposed to coarse (CP), fine (FP) and ultrafine particulate (UFP) or from the filtered air control group (FA), and then incubated with 10 nM [3H]-Angiotensin-II. Specific receptor binding was determined by subtracting the binding in the presence of 10 μM telmisartan. Scatter dot plot shows the value of the median. * Indicates significant differences among groups (n = 4 per group, p < 0.05)
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4482198&req=5

Fig3: Acute exposure to PM modifies [3H]-Angiotensin-II binding to the lung tissue membranes. a) Saturation binding. Membranes, obtained from naïve animals as described in Methods, were incubated with the indicated concentrations of [3H]-Angiotensin-II. Specific receptor binding was determined by subtracting the binding in the presence of 100 μM telmisartan from the total binding. The points show the means from quadruplicate determinations from a single experiment, which was repeated twice more with membranes obtained from different naïve animals. The line drawn is the best fit to a hyperbola. Best-fit values for the equilibrium dissociation constant (Kd) and maximum binding (Bmax) are given in the text. b) Single-point determinations. Membranes were obtained from animals exposed to coarse (CP), fine (FP) and ultrafine particulate (UFP) or from the filtered air control group (FA), and then incubated with 10 nM [3H]-Angiotensin-II. Specific receptor binding was determined by subtracting the binding in the presence of 10 μM telmisartan. Scatter dot plot shows the value of the median. * Indicates significant differences among groups (n = 4 per group, p < 0.05)
Mentions: Similar to other G protein-coupled receptors, upon activation AT1Rs can be internalized from the cell membrane to the cytoplasm and then can be either recycled or degraded. Because the reduction in AT1R protein after the acute exposure to FP and UFP did not match the mRNA levels, we performed a binding assay with labeled Ang-II as an alternative method to confirm the protein levels. First, we obtained a saturation curve to determine the receptor density and the affinity for [3H]-Angiotensin-II in lung membranes obtained from rats that were not used in the PM experiments. These determinations (Fig. 3a) yielded a maximum specific binding (Bmax) of 90 ± 10 fmol/mg protein (3 experiments) and an equilibrium dissociation constant (Kd) of 2.8 nM (pKd 17.2 ± 7.7).Fig. 3

Bottom Line: The PM fractions induced the expression of RAAS and KKS elements in the lungs and heart in a time-dependent manner.The AT1R lung protein showed a time-dependent change in subcellular distribution.In addition, the presence of AT1R in the heart was accompanied by a decrease in HO-1, which was concomitant with the induction of Acta1 and Col3a1 and the increment of IL-6.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Avenida Instituto Politécnico Nacional, 2508, México D. F, CP. 07360, Mexico. gammaztatzi@gmail.com.

ABSTRACT

Background: Particulate matter (PM) adverse effects on health include lung and heart damage. The renin-angiotensin-aldosterone (RAAS) and kallikrein-kinin (KKS) endocrine systems are involved in the pathophysiology of cardiovascular diseases and have been found to impact lung diseases. The aim of the present study was to evaluate whether PM exposure regulates elements of RAAS and KKS.

Methods: Sprague-Dawley rats were acutely (3 days) and subchronically (8 weeks) exposed to coarse (CP), fine (FP) or ultrafine (UFP) particulates using a particulate concentrator, and a control group exposed to filtered air (FA). We evaluated the mRNA of the RAAS components At1, At2r and Ace, and of the KKS components B1r, B2r and Klk-1 by RT-PCR in the lungs and heart. The ACE and AT1R protein were evaluated by Western blot, as were HO-1 and γGCSc as indicators of the antioxidant response and IL-6 levels as an inflammation marker. We performed a binding assay to determinate AT1R density in the lung, also the subcellular AT1R distribution in the lungs was evaluated. Finally, we performed a histological analysis of intramyocardial coronary arteries and the expression of markers of heart gene reprogramming (Acta1 and Col3a1).

Results: The PM fractions induced the expression of RAAS and KKS elements in the lungs and heart in a time-dependent manner. CP exposure induced Ace mRNA expression and regulated its protein in the lungs. Acute and subchronic exposure to FP and UFP induced the expression of At1r in the lungs and heart. All PM fractions increased the AT1R protein in a size-dependent manner in the lungs and heart after subchronic exposure. The AT1R lung protein showed a time-dependent change in subcellular distribution. In addition, the presence of AT1R in the heart was accompanied by a decrease in HO-1, which was concomitant with the induction of Acta1 and Col3a1 and the increment of IL-6. Moreover, exposure to all PM fractions increased coronary artery wall thickness.

Conclusion: We demonstrate that exposure to PM induces the expression of RAAS and KKS elements, including AT1R, which was the main target in the lungs and the heart.

No MeSH data available.


Related in: MedlinePlus