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Bradykinin/B 2 receptor activation regulates renin in M ‐ 1 cells via protein kinase C and nitric oxide

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ABSTRACT

In the collecting duct (CD), the interactions of renin angiotensin system (RAS) and kallikrein‐kinin system (KKS) modulate Na+ reabsorption, volume homeostasis, and blood pressure. In this study, we used a mouse kidney cortical CD cell line (M‐1 cells) to test the hypothesis that in the CD, the activation of bradykinin B2 receptor (B2R) increases renin synthesis and release. Physiological concentrations of bradykinin (BK) treatment of M‐1 cells increased renin mRNA and prorenin and renin protein contents in a dose‐dependent manner and increased threefold renin content in the cell culture media. These effects were mediated by protein kinase C (PKC) independently of protein kinase A (PKA) because B2R antagonism with Icatibant and PKC inhibition with calphostin C, prevented these responses, but PKA inhibition with H89 did not modify the effects elicited by the B2R activation. BK‐dependent stimulation of renin gene expression in CD cells also involved nitric oxide (NO) pathway because increased cGMP levels and inhibition of NO synthase with L‐NAME prevented it. Complementary renin immunohistochemical studies performed in kidneys from mice with conventional B2R knockout and conditional B2R knockout in the CD, showed marked decreased renin immunoreactivity in CD, regardless of the renin presence in juxtaglomerular cells in the knockout mice. These results indicate that the activation of B2R increases renin synthesis and release by the CD cells through PKC stimulation and NO release, which support further the interactions between the RAS and KKS.

No MeSH data available.


Bradykinin stimulates CD renin expression through a PKA‐independent and PKC‐dependent pathway. (A) and (D) qRT‐PCR amplification of M‐1 cells renin gene (Ren1C). Where indicated 10−10 mol/L bradykinin, 10−7 mol/L H89, a PKA inhibitor and 10−7 mol/L calphostin C, a PKC inhibitor were added in the M‐1 cell culture media for 6 h. Densitometric analysis of the specific bands (B) and (E) of either prorenin or (C) and (F) renin were normalized to β‐actin expression. Results were expressed as mean ± SE in arbitrary unities. In all graphs, significance (*) was defined as P < 0.05 compared to control (n = 5–6; one‐way ANOVA followed by Dunnet's post‐test).
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phy213211-fig-0004: Bradykinin stimulates CD renin expression through a PKA‐independent and PKC‐dependent pathway. (A) and (D) qRT‐PCR amplification of M‐1 cells renin gene (Ren1C). Where indicated 10−10 mol/L bradykinin, 10−7 mol/L H89, a PKA inhibitor and 10−7 mol/L calphostin C, a PKC inhibitor were added in the M‐1 cell culture media for 6 h. Densitometric analysis of the specific bands (B) and (E) of either prorenin or (C) and (F) renin were normalized to β‐actin expression. Results were expressed as mean ± SE in arbitrary unities. In all graphs, significance (*) was defined as P < 0.05 compared to control (n = 5–6; one‐way ANOVA followed by Dunnet's post‐test).

Mentions: To determine the intracellular pathway involved in the BK‐dependent stimulation of renin in M‐1 cells, we first treated M‐1 cells with BK in either the presence or absence of PKA inhibition with H89 (Fig. 4A–C). H89 (10−7 mol/L) did not alter the BK‐dependent stimulation of renin mRNA levels (Fig. 4A) and prorenin and renin contents (Fig. 4B and C). However, 10−7 mol/L calphostin C (Cph) – an inhibitor of DAG‐dependent PKC isoforms, completely abolished the stimulation of Ren1C gene (Fig. 4D) and prorenin and renin proteins (Fig. 4E and F) by BK.


Bradykinin/B 2 receptor activation regulates renin in M ‐ 1 cells via protein kinase C and nitric oxide
Bradykinin stimulates CD renin expression through a PKA‐independent and PKC‐dependent pathway. (A) and (D) qRT‐PCR amplification of M‐1 cells renin gene (Ren1C). Where indicated 10−10 mol/L bradykinin, 10−7 mol/L H89, a PKA inhibitor and 10−7 mol/L calphostin C, a PKC inhibitor were added in the M‐1 cell culture media for 6 h. Densitometric analysis of the specific bands (B) and (E) of either prorenin or (C) and (F) renin were normalized to β‐actin expression. Results were expressed as mean ± SE in arbitrary unities. In all graphs, significance (*) was defined as P < 0.05 compared to control (n = 5–6; one‐way ANOVA followed by Dunnet's post‐test).
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phy213211-fig-0004: Bradykinin stimulates CD renin expression through a PKA‐independent and PKC‐dependent pathway. (A) and (D) qRT‐PCR amplification of M‐1 cells renin gene (Ren1C). Where indicated 10−10 mol/L bradykinin, 10−7 mol/L H89, a PKA inhibitor and 10−7 mol/L calphostin C, a PKC inhibitor were added in the M‐1 cell culture media for 6 h. Densitometric analysis of the specific bands (B) and (E) of either prorenin or (C) and (F) renin were normalized to β‐actin expression. Results were expressed as mean ± SE in arbitrary unities. In all graphs, significance (*) was defined as P < 0.05 compared to control (n = 5–6; one‐way ANOVA followed by Dunnet's post‐test).
Mentions: To determine the intracellular pathway involved in the BK‐dependent stimulation of renin in M‐1 cells, we first treated M‐1 cells with BK in either the presence or absence of PKA inhibition with H89 (Fig. 4A–C). H89 (10−7 mol/L) did not alter the BK‐dependent stimulation of renin mRNA levels (Fig. 4A) and prorenin and renin contents (Fig. 4B and C). However, 10−7 mol/L calphostin C (Cph) – an inhibitor of DAG‐dependent PKC isoforms, completely abolished the stimulation of Ren1C gene (Fig. 4D) and prorenin and renin proteins (Fig. 4E and F) by BK.

View Article: PubMed Central - PubMed

ABSTRACT

In the collecting duct (CD), the interactions of renin angiotensin system (RAS) and kallikrein&#8208;kinin system (KKS) modulate Na+ reabsorption, volume homeostasis, and blood pressure. In this study, we used a mouse kidney cortical CD cell line (M&#8208;1 cells) to test the hypothesis that in the CD, the activation of bradykinin B2 receptor (B2R) increases renin synthesis and release. Physiological concentrations of bradykinin (BK) treatment of M&#8208;1 cells increased renin mRNA and prorenin and renin protein contents in a dose&#8208;dependent manner and increased threefold renin content in the cell culture media. These effects were mediated by protein kinase C (PKC) independently of protein kinase A (PKA) because B2R antagonism with Icatibant and PKC inhibition with calphostin C, prevented these responses, but PKA inhibition with H89 did not modify the effects elicited by the B2R activation. BK&#8208;dependent stimulation of renin gene expression in CD cells also involved nitric oxide (NO) pathway because increased cGMP levels and inhibition of NO synthase with L&#8208;NAME prevented it. Complementary renin immunohistochemical studies performed in kidneys from mice with conventional B2R knockout and conditional B2R knockout in the CD, showed marked decreased renin immunoreactivity in CD, regardless of the renin presence in juxtaglomerular cells in the knockout mice. These results indicate that the activation of B2R increases renin synthesis and release by the CD cells through PKC stimulation and NO release, which support further the interactions between the RAS and KKS.

No MeSH data available.