We estimate the sample size to 12 ( n = 3 per group). The mice were housed at stable room temperature in a 12/12 h light/dark cycle and accessed to standard rodent chow and water. After obtaining ethical approval, the animals were experimented in compliance with the guidelines approved by the Animal Care Ethics Committee of Second Xiangya Hospital, China. The UUO model was constructed by ligating the left ureter in mice (male, 8–10 weeks of age). C57BL/6 mice were obtained from Shanghai Model Organisms Center. The proximal tubule-specific RAGE or Atg7-deletion mice were produced by crossing RAGE or Atg7 (flox/flox) mice (obtained from Dr Wang Lab and Dr Xiong Lab, respectively) with PEPCK-Cre mice. Atg7 and GFP- LC3-I/II plasmid was constructed by the Ruqi company (Guangzhou, China). The RAGE siRNA and Atg7 siRNA were supplied by Santa Cruz Biotechnology. Recombinant human TGF-β1 (7754-BH) was obtained from R&D Systems (MN, USA). Anti-Stat3 (9139), Phospho-Stat3 (4074), Atg7 (2631), and LC3-I/II (4108) were supplied by Cell Signaling Technology (MA, USA), while anti-p62, SQSTM1 (Cat No.18420-1-AP) were obtained from Proteintech (IL, USA). These results contribute to our understanding of the renoprotection by proximal tubular RAGE deletion in response to UUO.Īnti-β-Tubulin (ab175186), anti-RAGE (ab216329), anti-fibronectin (ab2413), anti-Collagen І (ab138492), anti-Collagen III (ab184993), anti-vimentin (ab92547), and anti-α-SMA (ab124964) antibodies were purchased from Abcam (Cambridge, UK). In our present study, we found that RAGE was induced by TGF-β1 and UUO, and then mediated autophagy to increase the renal fibrosis via STAT3/Atg7 axis in vitro and vivo. According to the above literature, we hypothesize that proximal tubular RAGE can induce kidney fibrosis by regulating autophagy. But the function and pathway of proximal tubular RAGE in UUO-induced autophagy are still unclear. In addition, AGEs bind to RAGE and then induce autophagy in various diseases including heart disease and colorectal cancer, which suggested that RAGE partly mediates autophagy production. The data indicated that the roles of autophagy in UUO-kidney fibrosis remain controversial. For example, UUO-induced kidney fibrosis was exacerbated in PT-ATG5-KO autophagy deficiency mice or LC3(−/−) mice (deletion of LC3B), this was alleviated in PT-ATG7-KO autophagy deficiency mice in contrary. But the function and mechanism of proximal tubular RAGE in renal fibrosis remain unclear according to available data.Īutophagy is a process which cytoplasmic components are degraded by lysosomes, The role of autophagy is associated with the type of cell or tissue and the experimental model. Besides, previous study reported that global RAGE knockout mice reduced renal interstitial fibrosis via downregulation of transforming growth factor (TGF)-β.

Advanced glycation end products (AGEs) directly bind to RAGE, and leads to the increase of expression level of cytokines and growth factors, including vascular endothelial growth factor and connective tissue growth factor, finally results in glomerular injury. Recent studies report that it not only plays a pivotal role in early tissue repair in disease, but also is increased in the procession of occurrence and development of a variety diseases including cancer, diabetes, neurodegeneration. Receptor for advanced glycation end products (RAGE) regulates the innate immune response via binding of numerous exogenous and endogenous ligands. But mechanisms of tubular epithelium in renal fibrosis are still poorly understood. Emerging data suggest that the tubular epithelium regulates renal fibrosis. The existing treatments for renal fibrosis are only slightly effective or ineffective. Kidney fibrosis is a major pathological feature of CKD.

It is estimated that CKD existed in about more than 10% of adults in developed countries. Chronic kidney disease (CKD) has a high prevalence rate, which seriously affects human health.

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