Pirfenidone Attenuates Renal Tubulointerstitial Fibrosis through Inhibiting miR-21.
Our previous studies had shown pirfenidone (PFD) not only improved tubulointerstitial fibrosis (TIF) but also inhibited the expression of microRNA-21 (miR-21) in the renal tissue of unilateral urethral obstruction (UUO) rats. This study aims to investigate whether PFD can attenuate TIF through inhibiting miR-21 in UUO rats.
Sprague Dawley rats were divided randomly into sham-operated group, UUO group, and PFD and olmesartan (Olm) treatment groups. Samples were collected on day 14. Expression of miR-21, TGF-β1, Smad3, and Smad7 mRNA in the renal tissue was detected using real-time quantitative PCR. Immunohistochemistry was performed to assess the protein expressions of collagen III, E-cadherin, and α-SMA. Automated capillary Western blotting was used to detect the quantitative expression of TGF-β1, Smad3, p-Smad3, Smad7, collagen III, E-cadherin, and α-SMA in renal tissues. The expression of miR-21 and Smad7 mRNA and the protein levels of collagen III and α-SMA were examined in the miR-21-overexpressing cell line, NRK-52E.
Compared with the UUO group, both PFD and Olm inhibited renal tubular dilation, diffused epithelial cell degeneration and necrosis, and reduced renal interstitial edema, inflammatory cell infiltration, and collagen fiber deposition, while no significant difference between PFD group and Olm group. Informatics-based approaches identified Smad7 as a likely candidate for regulation by miR-21. Compared with the sham group, miR-21 expression was upregulated in the UUO group resulting in the downregulation of Smad7 expression due to degradation. The overexpression of miR-21 in the in vitro model downregulated Smad7 and promoted EMT and ECM accumulation. Protein levels of TGF-β1, Smad3, p-Smad3, collagen III, and α-SMA were upregulated, while E-cadherin protein was downregulated in the UUO group than in the sham group. PFD rather than Olm decreased the expression of miR-21 and increased the expression level of Smad7 mRNA and then inhibited the TGF-β1/Smad3 signaling pathway. Olm only downregulated the TGF-β1/Smad3 signaling pathway.
PFD improves TIF by downregulating the expression of miR-21, then elevating Smad7, and finally inhibiting the activation of the TGF-β1/Smad3 signaling pathway in UUO rats.
Bi L
，Huang Y
，Li J
，Yang X
，Hou G
，Zhai P
，Zhang Q
，Alhaji AA
，Yang Y
，Liu B
... -
《-》
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
... -
《-》
ResearchGate
(全网免费下载)
钛学术
(全网免费下载)
