Anti-renal fibrosis effect of asperulosidic acid via TGF-β1/smad2/smad3 and NF-κB signaling pathways in a rat model of unilateral ureteral obstruction.
Renal fibrosis is the most common pathway leading to end-stage renal disease. It is characterized by excess extracellular matrix (ECM) accumulation and renal tissue damage, subsequently leading to kidney failure. Asperulosidic acid (ASPA), a bioactive iridoid glycoside, exerts anti-tumor, anti-oxidant, and anti-inflammatory activities, but its effects on renal fibrosis induced by unilateral ureteral obstruction (UUO) have not yet been investigated.
This study aimed to investigate the protective effect of ASPA on renal fibrosis induced by UUO, and to explore its pharmacological mechanism.
Thirty-six Sprague-Dawley (SD) rats were randomly divided into six groups: sham group, UUO model group, three ASPA treatment groups (10, 20, and 40 mg/kg), and captopril group (20 mg/kg). Rats were administered vehicle, ASPA or captopril intraperitoneally once a day for 14 consecutive days. Urea nitrogen (BUN), uric acid (UA) and inflammatory factors in serum samples were evaluated on the 7th, 10th, and 14th day after renal fibrosis induction. In addition, the 12 h urine was collected to test the content of urinary protein (upro) on the 14th day. The obstructive renal tissues were collected for pathological analysis (hematoxylin and eosion (H&E) staining and Masson's Trichrome staining) and immunohistochemical analysis on the 14th day after renal fibrosis induction. The mRNA expression of related factors and the protein levels of smad2, smad3, and smad4 were measured in UUO-induced rats by real time PCR and Western blot, respectively.
The levels of BUN, UA, and upro were elevated in UUO-induced rats, but ASPA treatment improved renal function by reducing the levels of BUN, UA, and upro. The protein levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6, as well as the mRNA levels of TNF-α, IL-1β, IL-6, monocyte chemoattractant protein-1 (MCP-1) and interferon-γ (IFN-γ), were decreased after ASPA administration (10, 20 and 40 mg/kg) in a dose-dependent manner. The ASPA exerted an alleviation effect on the inflammatory response through inhibition of nuclear factor-kappa B (NF-κB) pathway. In addition, reductions in α-smooth muscle actin (α-SMA), collagen III, and fibronectin expression were observed after ASPA administration at doses of 20 and 40 mg/kg. Furthermore, the renal expression of transforming growth factor-β1 (TGF-β1), smad2, smad3, and smad4 was down-regulated by ASPA treatment at doses of 20 and 40 mg/kg.
ASPA possessed protective effects on renal interstitial fibrosis in UUO-induced rats. These effects may be through inhibition of the activation of NF-κB and TGF-β1/smad2/smad3 signaling pathways.
Xianyuan L
，Wei Z
，Yaqian D
，Dan Z
，Xueli T
，Zhanglu D
，Guanyi L
，Lan T
，Menghua L
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Lack of microRNA-155 ameliorates renal fibrosis by targeting PDE3A/TGF-β1/Smad signaling in mice with obstructive nephropathy.
Although microRNA-155 (miR-155) is implicated in the pathogenesis of several fibrotic diseases, information regarding its functional role in renal fibrosis is limited. The current study aims to investigate the effects of miR-155 on renal fibrosis in unilateral ureteral occlusion (UUO) mice. MiR-155 level was significantly increased in renal tissues of UUO mice and TGF-β1-treated HK2 cells. Masson's trichrome staining showed that delivery of adeno-associated virus encoding miR-155 inhibitor led to a decrease in renal fibrosis induced by UUO. The increased expression of plasminogen activator inhibitor type 1, collagen III and collagen IV was also inhibited after miR-155 inhibition. In addition, miR-155 knockdown also prevented TGF-β1-induced epithelial-mesenchymal transition, concomitantly with a restoration of E-cadherin expression and a decrease of vimentin expression. Computational analysis revealed that miR-155 directly targets at 3'UTR of PDE3A. Overexpression of miR-155 suppressed the luciferase activity and protein expression of PDE3A, whereas inhibition of miR-155 increased PDE3A luciferase activity and expression. Furthermore, miR-155 inhibited TGF-β1-induced the increase of TGF-β1 expression and Smad-2/3 phosphorylation in HK2 cells. In contrast, knockdown of PDE3A reversed the effect of miR-155 inhibition on TGF-β1 expression. This study demonstrates that knockdown of miR-155 attenuates renal fibrosis via inhibiting TGF-β1/Smad signaling activation by targeting the upstream molecule PDE3A. This study suggests that miR-155 inhibition may be a novel therapeutic approach for preventing fibrotic kidney diseases.
Xi W
，Zhao X
，Wu M
，Jia W
，Li H
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