Pharmacological effects of piceatannol and resveratrol on <i>in vivo</i> models of renal diseases.

<p>Pharmacological effects of piceatannol and resveratrol on <i>in vivo</i> models of renal diseases.</p

Piceatannol decreases renal fibrosis in the UUO kidney.

<p>(A-B) One day after UUO surgery, mice were received an intraperitoneal injection of vehicle or piceatannol (50 mg/kg/day) for 2 weeks. (A) Masson’s trichrome staining was performed to examine interstitial fibrosis: contralateral + vehicle, contralateral + piceatannol, UUO + vehicle, and UUO + piceatannol. Scale bar is 100 μm. (B) Immunofluorescent staining using anti-collagen type I antibody. A representative photomicrograph is shown. Scale bar is 100 μm.</p

Piceatannol does not suppress TGF-β1-Smad signaling in the UUO kidney.

<p>(A) Kidney lysates were used for western blot analysis. Antibodies against TGF-β1, p-Smad3 (Ser423/425), Smad3, Smad2, and Smad4 were used. GAPDH was used as a loading control. (B-E) Quantification analysis was performed using densitometry. The data are expressed as the means ± SD of the mice (n = 6 per group). **<i>P</i><0.01 and ***<i>P</i><0.001 compared with the contralateral kidney. NS indicates not significant compared with the UUO kidney.</p

Piceatannol reduces the mRNA level of fibrosis-related genes in the UUO kidney.

<p>(A-D) One day after UUO surgery, the mice received an intraperitoneal injection of vehicle or piceatannol (50 mg/kg/day) for 2 weeks. The transcription level of collagen type I (collagen type I), fibronectin, alpha smooth muscle actin (α-SMA), and connective tissue growth factor (CTGF) was determined using qRT-PCR in kidney tissues from UUO mice treated with vehicle or piceatannol. The data are expressed as the means ± SD of the mice (n = 6 per group). ***<i>P</i><0.001 compared with the contralateral kidney. ^#<i>P</i><0.05 and ^##<i>P</i><0.01 compared with the UUO kidney.</p

Piceatannol reduces extracellular matrix (ECM) protein and fibrosis marker protein expression in the UUO kidney.

<p>One day after UUO surgery, the mice received an intraperitoneal injection of vehicle or piceatannol (50 mg/kg/day) for 2 weeks. (A) Protein lysates from kidney tissues were prepared and were analyzed using western blotting. Anti-collagen 1, fibronectin, α-SMA, and CTGF antibodies were used. GADPH was used as a loading control. Representative immunoblots. (B-E) Protein levels were quantified using densitometry. The data are expressed as the means ± SD of the mice (n = 6 per group). ***<i>P</i><0.001 compared with the contralateral kidney. ^##<i>P</i><0.01 and ^###<i>P</i><0.001 compared with the UUO kidney.</p

HDAC1 protein expression is upregulated in the UUO kidney.

<p>(A) Kidney protein lysates were analyzed using western blotting. Antibodies against HDAC1, HDAC2, HDAC3, and HDAC8 were used. GAPDH was used as a loading control. (B-E) Quantification analysis was performed using densitometry. The data are expressed as the means ± SD of the mice (n = 6 per group). *<i>P</i><0.05 and ***<i>P</i><0.001 compared with the contralateral kidney. NS indicates not significant.</p

Piceatannol attenuates phosphorylated p38 MAPK expression in the UUO kidney.

<p>(A) Kidney lysates were used for western blot analysis. Antibodies against p-JNK2 (Thr183/Tyr185), JNK2, p-ERK1 (Thr202/Tyr204), ERK1, p-p38 (Thr180/Tyr182), and p38 were used. GAPDH was used as a loading control. (B-E) Quantification analysis was performed using densitometry. The data are expressed as the means ± SD of the mice (n = 6 per group). *<i>P</i><0.05, **<i>P</i><0.01, and ***<i>P</i><0.001 compared with the contralateral kidney. ^#<i>P</i> <0.05 compared with the UUO kidney. NS indicates not significant compared with the UUO kidney.</p

Piceatannol suppresses renal fibrosis by downregulation of the p38-MAPK/HDAC4/5 pathway.

<p>Fibrotic stress such as UUO can induce TGF-β1 expression, which causes phosphorylation and upregulation of Smad2/3 or MAPK (JNK2, ERK1/2, or p38) protein expression. It also increases the expression of class II HDACs (HDAC4/5). Piceatannol attenuates the activation of p38-MAPK signaling and the increased HDAC4/5 expression, but not the activation of the TGF-β1/Smad3 signaling pathway. However, whether a direct association between HDAC4/5 and MAPK signaling or between HDAC4/5 and renal fibrosis exists remains unknown. TβRII and TβRI indicate TGFβ receptor II and TGFβ receptor I, respectively.</p

Piceatannol attenuates the expression of UUO-induced renal HDAC5/HDAC6 protein.

<p>(A) Kidney lysates were used for western blot analysis. Antibodies against HDAC4, HDAC5, HDAC6, and HDAC10 were used. GAPDH was used as a loading control. (B-E) Quantification analysis was performed using densitometry. The data are expressed as the means ± SD of the mice (n = 6 per group). *<i>P</i><0.05 and ***<i>P</i><0.001 compared with the contralateral kidney. ^###<i>P</i> <0.001 compared with the UUO kidney. NS indicates not significant compared with the UUO kidney.</p

Epithelial-mesenchymal transition (EMT) gene expression is not observed in the UUO kidney.

<p>One day after UUO surgery, the mice received an intraperitoneal injection of vehicle or piceatannol (50 mg/kg/day) for 2 weeks. (A) Protein lysates from kidney tissues were prepared and were analyzed using western blotting. N-cadherin and E-cadherin antibodies were used. GADPH was used as a loading control. Representative immunoblots. (B-C) Protein levels were quantified using densitometry. The data are expressed as the means ± SD of the mice (n = 6 per group). NS indicates not significant. ^#<i>P</i><0.05 compared with the UUO kidney.</p