Urology Department, Third Affiliated Hospital of Soochow University, 185# Juqian Street, Changzhou, 213003, China.
In Vitro Cell Dev Biol Anim. 2021 Jun;57(6):649-659. doi: 10.1007/s11626-021-00598-y. Epub 2021 Jun 14.
Aberrant expression of B cell-activating factor belonging to TNF superfamily (BAFF) and its receptors results in abnormal biological activities in hematopoietic and non-hematopoietic cells and is closely associated with the occurrence and development of various diseases. However, the biological significance and potential mechanisms underlying BAFF signaling in renal tubular epithelial cells (RTECs) remain unknown. This study aimed to investigate the biological role of BAFF signaling in RTECs. Mice primary RTECs were applied. The proliferation status and apoptotic rates were examined by MTS assay and flow cytometry, respectively. The expression of BAFF and its receptors was analyzed via flow cytometry and sodium ion transport function, and cytokeratin-18 expression was detected through immunofluorescence staining. In addition, Pin1 was knocked down via siRNA and its expression was assessed through reverse transcription PCR. Lastly, western blotting was performed to analyze E-cadherin, ɑ-SMA, and Pin1 expression. Results suggested that BAFF-R was significantly upregulated upon IFN-γ stimulation, and enhancement of BAFF signaling promoted cell survival and reduced their apoptotic rate, while simultaneously reducing the epithelial phenotype and promoting the interstitial transformation of cells. Furthermore, Pin1 was significantly increased, along with the upregulation of BAFF signaling in the RTECs, and participated in interstitial transformation induced by BAFF signaling. Collectively, the present results elucidate the potential mechanism of loss of normal function of RTECs under long-term high dose of BAFF stimulation provides a potential therapeutic target for renal interstitial fibrosis, and underlining mechanisms of shortening of long-term outcomes of kidney allografts via augmenting of BAFF signaling.
B 细胞激活因子属于 TNF 超家族（BAFF）及其受体的异常表达导致造血和非造血细胞的异常生物学活性，与各种疾病的发生和发展密切相关。然而，BAFF 信号在肾小管上皮细胞（RTECs）中的生物学意义和潜在机制尚不清楚。本研究旨在探讨 BAFF 信号在 RTECs 中的生物学作用。应用小鼠原代 RTECs。通过 MTS 检测和流式细胞术分别检测细胞增殖状态和凋亡率。通过流式细胞术和钠离子转运功能分析 BAFF 及其受体的表达，通过免疫荧光染色检测细胞角蛋白-18 的表达。此外，通过 siRNA 敲低 Pin1，并通过逆转录 PCR 评估其表达。最后，通过 Western blot 分析 E-cadherin、α-SMA 和 Pin1 的表达。结果表明，IFN-γ 刺激后 BAFF-R 显著上调，增强 BAFF 信号促进细胞存活并降低其凋亡率，同时减少上皮表型并促进细胞间质转化。此外，Pin1 随着 BAFF 信号在 RTECs 中的上调而显著增加，并参与 BAFF 信号诱导的间质转化。综上所述，本研究结果阐明了 RTECs 在长期高剂量 BAFF 刺激下正常功能丧失的潜在机制，为肾间质纤维化提供了一个潜在的治疗靶点，并强调了通过增强 BAFF 信号来缩短肾移植长期预后的机制。
