Department of Nephrology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China.
J Diabetes Res. 2021 Oct 11;2021:5584871. doi: 10.1155/2021/5584871. eCollection 2021.
We previously observed that adenosine A1 receptor (A1AR) had a protective role in proximal tubular megalin loss associated with albuminuria in diabetic nephropathy (DN). In this study, we aimed to explore the role of A1AR in the fibrosis progression of DN.
We collected DN patients' samples and established a streptozotocin-induced diabetes model in wild-type (WT) and A1AR-deficient (A1AR) mice. The location and expression of CD34, PDGFR, and A1AR were detected in kidney tissue samples from DN patients by immunofluorescent and immunohistochemical staining. We also analyzed the expression of TGF, collagen (I, III, and IV), -SMA, and PDGFR using immunohistochemistry in WT and A1AR mice. CD34 and podoplanin expression were analyzed by Western blotting and immunohistochemical staining in mice, respectively. Human renal proximal tubular epithelial cells (HK2) were cultured in medium containing high glucose and A1AR agonist as well as antagonist.
In DN patients, the expression of PDGFR was higher with the loss of CD34. The location of PDGFR and TGF was near to each other. The A1AR, which was colocalized with CD34 partly, was also upregulated in DN patients. In WT-DN mice, obvious albuminuria and renal pathological leisure were observed. In A1AR DN mice, more severe renal tubular interstitial fibrosis and more extracellular matrix deposition were observed, with lower CD34 expression and pronounced increase of PDGFR. In HK2 cells, high glucose stimulated the epithelial-mesenchymal transition (EMT) process, which was inhibited by A1AR agonist.
A1AR played a critical role in protecting the tubulointerstitial fibrosis process in DN by regulation of the peritubular microenvironment.
我们之前观察到，在糖尿病肾病（DN）中，与白蛋白尿相关的近端肾小管 megalin 丢失时，腺苷 A1 受体（A1AR）具有保护作用。在这项研究中，我们旨在探讨 A1AR 在 DN 纤维化进展中的作用。
我们收集了 DN 患者的样本，并在野生型（WT）和 A1AR 缺陷型（A1AR）小鼠中建立了链脲佐菌素诱导的糖尿病模型。通过免疫荧光和免疫组织化学染色，检测了 DN 患者肾组织样本中 CD34、PDGFR 和 A1AR 的位置和表达。我们还分析了 WT 和 A1AR 小鼠中 TGF、胶原（I、III 和 IV）、-SMA 和 PDGFR 的表达。通过 Western 印迹和免疫组织化学染色，分别分析了小鼠的 CD34 和 podoplanin 表达。培养人肾近端管状上皮细胞（HK2），使其在含有高葡萄糖和 A1AR 激动剂及拮抗剂的培养基中生长。
在 DN 患者中，PDGFR 的表达随着 CD34 的丢失而升高。PDGFR 和 TGF 的位置彼此相邻。A1AR 也在 DN 患者中上调，与 CD34 部分共定位。在 WT-DN 小鼠中，观察到明显的白蛋白尿和肾脏病理疏松。在 A1AR-DN 小鼠中，观察到更严重的肾小管间质纤维化和更多的细胞外基质沉积，CD34 表达降低，PDGFR 明显增加。在 HK2 细胞中，高葡萄糖刺激上皮-间充质转化（EMT）过程，该过程被 A1AR 激动剂抑制。
A1AR 通过调节肾小管周围的微环境，在 DN 的肾小管间质纤维化过程中发挥关键作用。
