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Chronic NF-κB blockade improves renal angiotensin II type 1 receptor functions and reduces blood pressure in Zucker diabetic rats.

Luo H, Wang X, Wang J, Chen C, Wang N, Xu Z, Chen S, Zeng C - Cardiovasc Diabetol (2015)

Bottom Line: The NF-κB-DNA binding activity in renal cortex was measured by Electrophoretic mobility shift assay (EMSA).It resulted that PDTC inhibited NF-κB translocation from cytosol to nucleus, inhibited binding of NF-κB with AT1R promoter, therefore, reduced AT1R expression and function.Our present study indicates blockade of NF-κB, via inhibition of binding of NF-κB with AT1R promoter, reduces renal AT1R expression and function, improves oxidative stress and inflammatory/anti-inflammatory balance, therefore, lowers blood pressure and recovers renal function in ZDF rats.

View Article: PubMed Central - PubMed

Affiliation: The Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China. lh060608@163.com.

ABSTRACT

Background: Both angiotensin II type 1 receptor (AT1R) and nuclear factor-kappa B (NF-κB) play significant roles in the pathogenesis of hypertension and type 2 diabetes. However, the role of NF-κB in perpetuating renal AT1 receptors dysfunction remains unclear. The aim of the present study to determine whether blockade of NF-κB, could reverse the exaggerated renal AT1R function, reduce inflammatory state and oxidative stress, lower blood pressure in Zucker diabetic fatty (ZDF) rats.

Methods: Pyrrolidine dithiocarbamate (PDTC), a NF-κB inhibitor (150 mg/kg in drinking water)or vehicle was administered orally to 12-weeks-old ZDF rats and their respective control lean Zucker (LZ) rats for 4 weeks. Blood pressure was measured weekly by tail-cuff method. AT1R functions were determined by measuring diuretic and natriuretic responses to AT1R antagonist (candesartan; 10 μg/kg/min iv). The mRNA and protein levels of NF-κB, oxidative stress maker and AT1R were determined using quantitative real-time PCR and Western blotting, respectively. The NF-κB-DNA binding activity in renal cortex was measured by Electrophoretic mobility shift assay (EMSA).

Results: As compared with LZ rats, ZDF rats had higher blood pressure, impaired natriuresis and diuresis, accompanied with higher levels of oxidative stress and inflammation. Furthermore, AT1R expression was higher in renal cortex from ZDF rats; candesartan induced natriresis and diuresis, which was augmented in ZDF rats. Treatment with PDTC lowered blood pressure and improved diuretic and natriuretic effects in ZDF rats; meanwhile, the increased oxidative stress and inflammation were reduced; the increased AT1R expression and augmented candesartan-mediated natriuresis and diuresis were recoverd in ZDF rats. Our further study investigated the mechanisms of PDTC on AT1R receptor expression. It resulted that PDTC inhibited NF-κB translocation from cytosol to nucleus, inhibited binding of NF-κB with AT1R promoter, therefore, reduced AT1R expression and function.

Conclusions: Our present study indicates blockade of NF-κB, via inhibition of binding of NF-κB with AT1R promoter, reduces renal AT1R expression and function, improves oxidative stress and inflammatory/anti-inflammatory balance, therefore, lowers blood pressure and recovers renal function in ZDF rats.

No MeSH data available.


Related in: MedlinePlus

Effect of PDTC on NF-κB signaling in the renal cortex of LZ and ZDF rats. LZ or ZDF rats were treated with PDTC (150 mg · kg body wt-1 · day-1) or vehicle for 4 weeks. a: Phosphorylation and expression of IKK and IκBα were determined by Western blot, and data were normalized using GAPDH expression. Nuclear and cytosol protein were prepared from the renal cortex and the expression of NF-κB in nuclear (Nu) (b) and cytosol (Cyto) (c) fractions were determined by Western blot. *P <0.05 vs LZ control; #P < 0.05 vs ZDF control (n = 5)
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Fig6: Effect of PDTC on NF-κB signaling in the renal cortex of LZ and ZDF rats. LZ or ZDF rats were treated with PDTC (150 mg · kg body wt-1 · day-1) or vehicle for 4 weeks. a: Phosphorylation and expression of IKK and IκBα were determined by Western blot, and data were normalized using GAPDH expression. Nuclear and cytosol protein were prepared from the renal cortex and the expression of NF-κB in nuclear (Nu) (b) and cytosol (Cyto) (c) fractions were determined by Western blot. *P <0.05 vs LZ control; #P < 0.05 vs ZDF control (n = 5)

Mentions: It is known that NF-κB is the vital signaling of oxidative stress and inflammation on AT1R expression, we checked NF-κB related pathway, it showed that there was a marked increase in phosphorylation of IKK and IκBα in ZDF rats, which was accompanied by decreased protein expression of IκBα (Fig. 6a). Nuclear translocation of NF-κB was also observed in the kidney of ZDF rats. This was reflected by increased expression of NF-κB p65 subunits, in the nuclear fraction, and decreased expression of NF-κB p65 subunits in the cytosolic fraction (Fig. 6b and c). The binding activity of NF-κB binding to the AT1R promoter was significantly higher in renal cortices of ZDF than in LZ rats by EMSA analysis (Fig. 7). As an inhibitor of NF-κB, PDTC inhibited phosphorylation of IKK and IκBα, increased IκBα expression, blocked the translocation of NF-κB from cytosolic to nuclear fraction, therefore, decreased the binding of NF-κB with AT1R promoter, and decreased AT1R expression in kidney from ZDF rats (Fig. 6 and 7).Fig. 6


Chronic NF-κB blockade improves renal angiotensin II type 1 receptor functions and reduces blood pressure in Zucker diabetic rats.

Luo H, Wang X, Wang J, Chen C, Wang N, Xu Z, Chen S, Zeng C - Cardiovasc Diabetol (2015)

Effect of PDTC on NF-κB signaling in the renal cortex of LZ and ZDF rats. LZ or ZDF rats were treated with PDTC (150 mg · kg body wt-1 · day-1) or vehicle for 4 weeks. a: Phosphorylation and expression of IKK and IκBα were determined by Western blot, and data were normalized using GAPDH expression. Nuclear and cytosol protein were prepared from the renal cortex and the expression of NF-κB in nuclear (Nu) (b) and cytosol (Cyto) (c) fractions were determined by Western blot. *P <0.05 vs LZ control; #P < 0.05 vs ZDF control (n = 5)
© Copyright Policy - open-access
Related In: Results  -  Collection

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Fig6: Effect of PDTC on NF-κB signaling in the renal cortex of LZ and ZDF rats. LZ or ZDF rats were treated with PDTC (150 mg · kg body wt-1 · day-1) or vehicle for 4 weeks. a: Phosphorylation and expression of IKK and IκBα were determined by Western blot, and data were normalized using GAPDH expression. Nuclear and cytosol protein were prepared from the renal cortex and the expression of NF-κB in nuclear (Nu) (b) and cytosol (Cyto) (c) fractions were determined by Western blot. *P <0.05 vs LZ control; #P < 0.05 vs ZDF control (n = 5)
Mentions: It is known that NF-κB is the vital signaling of oxidative stress and inflammation on AT1R expression, we checked NF-κB related pathway, it showed that there was a marked increase in phosphorylation of IKK and IκBα in ZDF rats, which was accompanied by decreased protein expression of IκBα (Fig. 6a). Nuclear translocation of NF-κB was also observed in the kidney of ZDF rats. This was reflected by increased expression of NF-κB p65 subunits, in the nuclear fraction, and decreased expression of NF-κB p65 subunits in the cytosolic fraction (Fig. 6b and c). The binding activity of NF-κB binding to the AT1R promoter was significantly higher in renal cortices of ZDF than in LZ rats by EMSA analysis (Fig. 7). As an inhibitor of NF-κB, PDTC inhibited phosphorylation of IKK and IκBα, increased IκBα expression, blocked the translocation of NF-κB from cytosolic to nuclear fraction, therefore, decreased the binding of NF-κB with AT1R promoter, and decreased AT1R expression in kidney from ZDF rats (Fig. 6 and 7).Fig. 6

Bottom Line: The NF-κB-DNA binding activity in renal cortex was measured by Electrophoretic mobility shift assay (EMSA).It resulted that PDTC inhibited NF-κB translocation from cytosol to nucleus, inhibited binding of NF-κB with AT1R promoter, therefore, reduced AT1R expression and function.Our present study indicates blockade of NF-κB, via inhibition of binding of NF-κB with AT1R promoter, reduces renal AT1R expression and function, improves oxidative stress and inflammatory/anti-inflammatory balance, therefore, lowers blood pressure and recovers renal function in ZDF rats.

View Article: PubMed Central - PubMed

Affiliation: The Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, PR China. lh060608@163.com.

ABSTRACT

Background: Both angiotensin II type 1 receptor (AT1R) and nuclear factor-kappa B (NF-κB) play significant roles in the pathogenesis of hypertension and type 2 diabetes. However, the role of NF-κB in perpetuating renal AT1 receptors dysfunction remains unclear. The aim of the present study to determine whether blockade of NF-κB, could reverse the exaggerated renal AT1R function, reduce inflammatory state and oxidative stress, lower blood pressure in Zucker diabetic fatty (ZDF) rats.

Methods: Pyrrolidine dithiocarbamate (PDTC), a NF-κB inhibitor (150 mg/kg in drinking water)or vehicle was administered orally to 12-weeks-old ZDF rats and their respective control lean Zucker (LZ) rats for 4 weeks. Blood pressure was measured weekly by tail-cuff method. AT1R functions were determined by measuring diuretic and natriuretic responses to AT1R antagonist (candesartan; 10 μg/kg/min iv). The mRNA and protein levels of NF-κB, oxidative stress maker and AT1R were determined using quantitative real-time PCR and Western blotting, respectively. The NF-κB-DNA binding activity in renal cortex was measured by Electrophoretic mobility shift assay (EMSA).

Results: As compared with LZ rats, ZDF rats had higher blood pressure, impaired natriuresis and diuresis, accompanied with higher levels of oxidative stress and inflammation. Furthermore, AT1R expression was higher in renal cortex from ZDF rats; candesartan induced natriresis and diuresis, which was augmented in ZDF rats. Treatment with PDTC lowered blood pressure and improved diuretic and natriuretic effects in ZDF rats; meanwhile, the increased oxidative stress and inflammation were reduced; the increased AT1R expression and augmented candesartan-mediated natriuresis and diuresis were recoverd in ZDF rats. Our further study investigated the mechanisms of PDTC on AT1R receptor expression. It resulted that PDTC inhibited NF-κB translocation from cytosol to nucleus, inhibited binding of NF-κB with AT1R promoter, therefore, reduced AT1R expression and function.

Conclusions: Our present study indicates blockade of NF-κB, via inhibition of binding of NF-κB with AT1R promoter, reduces renal AT1R expression and function, improves oxidative stress and inflammatory/anti-inflammatory balance, therefore, lowers blood pressure and recovers renal function in ZDF rats.

No MeSH data available.


Related in: MedlinePlus