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Involvement of Cyclic Guanosine Monophosphate-Dependent Protein Kinase I in Renal Antifibrotic Effects of Serelaxin.

Wetzl V, Schinner E, Kees F, Hofmann F, Faerber L, Schlossmann J - Front Pharmacol (2016)

Bottom Line: The profibrotic connective tissue growth factor as well as myofibroblast differentiation were reduced and matrix metalloproteinases-2 and -9 were positively modulated after treatment.Moreover, Smad2 as well as extracellular signal-regulated kinase 1 (ERK1) phosphorylation were decreased, whereas phosphodiesterase (PDE) 5a phosphorylation was increased.However, these effects were not observed in cGKI-KO.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Toxicology, University of RegensburgRegensburg, Germany; Novartis Pharma GmbHNuremberg, Germany.

ABSTRACT

Introduction: Kidney fibrosis has shown to be ameliorated through the involvement of cyclic guanosine monophosphate (cGMP) and its dependent protein kinase I (cGKI). Serelaxin, the recombinant form of human relaxin-II, increases cGMP levels and has shown beneficial effects on kidney function in acute heart failure patients. Antifibrotic properties of serelaxin are supposed to be mediated via relaxin family peptide receptor 1 and subsequently enhanced nitric oxide/cGMP to inhibit transforming growth factor-β (TGF-β) signaling. This study examines the involvement of cGKI in the antifibrotic signaling of serelaxin.

Methods and results: Kidney fibrosis was induced by unilateral ureteral obstruction in wildtype (WT) and cGKI knock-out (KO) mice. After 7 days, renal antifibrotic effects of serelaxin were assessed. Serelaxin treatment for 7 days significantly increased cGMP in the kidney of WT and cGKI-KO. In WT, renal fibrosis was reduced through decreased accumulation of collagen1A1, total collagen, and fibronectin. The profibrotic connective tissue growth factor as well as myofibroblast differentiation were reduced and matrix metalloproteinases-2 and -9 were positively modulated after treatment. Moreover, Smad2 as well as extracellular signal-regulated kinase 1 (ERK1) phosphorylation were decreased, whereas phosphodiesterase (PDE) 5a phosphorylation was increased. However, these effects were not observed in cGKI-KO.

Conclusion: Antifibrotic renal effects of serelaxin are mediated via cGMP/cGKI to inhibit Smad2- and ERK1-dependent TGF-β signaling and increased PDE5a phosphorylation.

No MeSH data available.


Related in: MedlinePlus

Effect of serelaxin on (A) mRNA and (B) protein expression of α-SMA in kidney tissue of WT and cGKI-KO mice. mRNA was determined with RT-qPCR and 18s rRNA as housekeeping gene. Results are shown as fold change of mRNA expression (2ΔΔct) in the fibrotic kidney relative to contralateral healthy kidney, which was set as 1. The increase of α-SMA protein expression [%] in fibrotic renal tissue compared to contralateral kidney was quantified by immunohistochemistry; α-SMA, α-smooth muscle actin; cGKI, cGMP-dependent protein kinase I; KO, knockout; RLX, serelaxin; UUO, unilateral ureteral obstruction; WT, wildtype, ∗p < 0.05.
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Figure 2: Effect of serelaxin on (A) mRNA and (B) protein expression of α-SMA in kidney tissue of WT and cGKI-KO mice. mRNA was determined with RT-qPCR and 18s rRNA as housekeeping gene. Results are shown as fold change of mRNA expression (2ΔΔct) in the fibrotic kidney relative to contralateral healthy kidney, which was set as 1. The increase of α-SMA protein expression [%] in fibrotic renal tissue compared to contralateral kidney was quantified by immunohistochemistry; α-SMA, α-smooth muscle actin; cGKI, cGMP-dependent protein kinase I; KO, knockout; RLX, serelaxin; UUO, unilateral ureteral obstruction; WT, wildtype, ∗p < 0.05.

Mentions: mRNA of α-SMA, a marker of myofibroblast differentiation, (Nagamoto et al., 2000) was increased in both WT and cGKI-KO after UUO. A reduction of mRNA was observed after treatment with RLX in WT, whereas no effect was seen in cGKI-KO after treatment (Figure 2A). As expected, in unobstructed renal tissue only vascular smooth muscle cells were immunostained with α-SMA, in UUO-obstructed kidneys enhanced interstitial expression was observed (data not shown). In WT, α-SMA protein was elevated compared to the contralateral kidney, after RLX treatment the increase was significantly reduced. In cGKI-KO no significant reduction of α-SMA protein expression through RLX was demonstrated (Figure 2B).


Involvement of Cyclic Guanosine Monophosphate-Dependent Protein Kinase I in Renal Antifibrotic Effects of Serelaxin.

Wetzl V, Schinner E, Kees F, Hofmann F, Faerber L, Schlossmann J - Front Pharmacol (2016)

Effect of serelaxin on (A) mRNA and (B) protein expression of α-SMA in kidney tissue of WT and cGKI-KO mice. mRNA was determined with RT-qPCR and 18s rRNA as housekeeping gene. Results are shown as fold change of mRNA expression (2ΔΔct) in the fibrotic kidney relative to contralateral healthy kidney, which was set as 1. The increase of α-SMA protein expression [%] in fibrotic renal tissue compared to contralateral kidney was quantified by immunohistochemistry; α-SMA, α-smooth muscle actin; cGKI, cGMP-dependent protein kinase I; KO, knockout; RLX, serelaxin; UUO, unilateral ureteral obstruction; WT, wildtype, ∗p < 0.05.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940422&req=5

Figure 2: Effect of serelaxin on (A) mRNA and (B) protein expression of α-SMA in kidney tissue of WT and cGKI-KO mice. mRNA was determined with RT-qPCR and 18s rRNA as housekeeping gene. Results are shown as fold change of mRNA expression (2ΔΔct) in the fibrotic kidney relative to contralateral healthy kidney, which was set as 1. The increase of α-SMA protein expression [%] in fibrotic renal tissue compared to contralateral kidney was quantified by immunohistochemistry; α-SMA, α-smooth muscle actin; cGKI, cGMP-dependent protein kinase I; KO, knockout; RLX, serelaxin; UUO, unilateral ureteral obstruction; WT, wildtype, ∗p < 0.05.
Mentions: mRNA of α-SMA, a marker of myofibroblast differentiation, (Nagamoto et al., 2000) was increased in both WT and cGKI-KO after UUO. A reduction of mRNA was observed after treatment with RLX in WT, whereas no effect was seen in cGKI-KO after treatment (Figure 2A). As expected, in unobstructed renal tissue only vascular smooth muscle cells were immunostained with α-SMA, in UUO-obstructed kidneys enhanced interstitial expression was observed (data not shown). In WT, α-SMA protein was elevated compared to the contralateral kidney, after RLX treatment the increase was significantly reduced. In cGKI-KO no significant reduction of α-SMA protein expression through RLX was demonstrated (Figure 2B).

Bottom Line: The profibrotic connective tissue growth factor as well as myofibroblast differentiation were reduced and matrix metalloproteinases-2 and -9 were positively modulated after treatment.Moreover, Smad2 as well as extracellular signal-regulated kinase 1 (ERK1) phosphorylation were decreased, whereas phosphodiesterase (PDE) 5a phosphorylation was increased.However, these effects were not observed in cGKI-KO.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Toxicology, University of RegensburgRegensburg, Germany; Novartis Pharma GmbHNuremberg, Germany.

ABSTRACT

Introduction: Kidney fibrosis has shown to be ameliorated through the involvement of cyclic guanosine monophosphate (cGMP) and its dependent protein kinase I (cGKI). Serelaxin, the recombinant form of human relaxin-II, increases cGMP levels and has shown beneficial effects on kidney function in acute heart failure patients. Antifibrotic properties of serelaxin are supposed to be mediated via relaxin family peptide receptor 1 and subsequently enhanced nitric oxide/cGMP to inhibit transforming growth factor-β (TGF-β) signaling. This study examines the involvement of cGKI in the antifibrotic signaling of serelaxin.

Methods and results: Kidney fibrosis was induced by unilateral ureteral obstruction in wildtype (WT) and cGKI knock-out (KO) mice. After 7 days, renal antifibrotic effects of serelaxin were assessed. Serelaxin treatment for 7 days significantly increased cGMP in the kidney of WT and cGKI-KO. In WT, renal fibrosis was reduced through decreased accumulation of collagen1A1, total collagen, and fibronectin. The profibrotic connective tissue growth factor as well as myofibroblast differentiation were reduced and matrix metalloproteinases-2 and -9 were positively modulated after treatment. Moreover, Smad2 as well as extracellular signal-regulated kinase 1 (ERK1) phosphorylation were decreased, whereas phosphodiesterase (PDE) 5a phosphorylation was increased. However, these effects were not observed in cGKI-KO.

Conclusion: Antifibrotic renal effects of serelaxin are mediated via cGMP/cGKI to inhibit Smad2- and ERK1-dependent TGF-β signaling and increased PDE5a phosphorylation.

No MeSH data available.


Related in: MedlinePlus