Department of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan.
University Center for Bioscience and Biotechnology, National Cheng Kung University, Tainan 70101, Taiwan.
Cells. 2022 Jan 30;11(3):483. doi: 10.3390/cells11030483.
Polycystic kidney disease (PKD) is one of the most common inherited diseases and is characterized by the development of fluid-filled cysts along multiple segments of the nephron. Autosomal dominant polycystic kidney disease (ADPKD) is the most common form of PKD, which is caused by mutations in either or genes that encode polycystin-1 (PC1) and polycystin-2 (PC2), respectively. As ADPKD progresses, cysts enlarge and disrupt normal kidney architecture, eventually leading to kidney failure. Our previous study showed that overexpression of exogenous kidney-specific neutrophil gelatinase-associated lipocalin (NGAL) reduced cyst progression and prolonged the lifespan of ADPKD mice (, 2L3 for short). In this study, we attempted to explore the underlying mechanism of reduced cyst progression in the presence of NGAL using immortalized 2L3 cells. The results of MTT and BrdU incorporation assays showed that recombinant mouse NGAL (mNGAL) protein significantly decreased the viability and proliferation of 2L3 cells. Flow cytometry and western blot analyses showed that mNGAL inhibited activation of the ERK and AKT pathways and induced apoptosis and autophagy in 2L3 cells. In addition, a 3D cell culture platform was established to identify cyst progression in 2L3 cells and showed that mNGAL significantly inhibited cyst enlargement in 2L3 cells. Overexpression of secreted mNGAL (pN + LS) and nonsecreted mNGAL (pN - LS) repressed cell proliferation and cyst enlargement in 2L3 cells and had effects on markers involved in proliferation, apoptosis, and autophagy. However, secreted mNGAL had a more pronounced and consistent effect than that of nonsecreted form. These results reveal that secreted mNGAL has stronger ability to inhibit cyst enlargement of ADPKD cells than that of nonsecreted form. These findings could help to identify strategies for the future clinical treatment of ADPKD.
多囊肾病（PKD）是最常见的遗传性疾病之一，其特征是在多个肾单位段出现充满液体的囊肿。常染色体显性多囊肾病（ADPKD）是最常见的 PKD 形式，由编码多囊蛋白-1（PC1）和多囊蛋白-2（PC2）的 或 基因中的突变引起。随着 ADPKD 的进展，囊肿增大并破坏正常的肾脏结构，最终导致肾衰竭。我们之前的研究表明，外源性肾脏特异性中性粒细胞明胶酶相关脂质运载蛋白（NGAL）的过表达可减少囊肿进展并延长 ADPKD 小鼠的寿命（简称 2L3）。在这项研究中，我们试图探索 NGAL 存在时减少囊肿进展的潜在机制，使用永生化的 2L3 细胞。MTT 和 BrdU 掺入测定的结果表明，重组小鼠 NGAL（mNGAL）蛋白显著降低了 2L3 细胞的活力和增殖。流式细胞术和 Western blot 分析表明，mNGAL 抑制了 ERK 和 AKT 通路的激活，并诱导了 2L3 细胞的凋亡和自噬。此外，建立了一个 3D 细胞培养平台来鉴定 2L3 细胞中的囊肿进展，结果表明 mNGAL 显著抑制了 2L3 细胞的囊肿增大。分泌型 mNGAL（pN + LS）和非分泌型 mNGAL（pN - LS）的过表达抑制了 2L3 细胞的增殖和囊肿增大，并对涉及增殖、凋亡和自噬的标志物产生影响。然而，分泌型 mNGAL 的作用比非分泌型更明显和一致。这些结果表明，分泌型 mNGAL 抑制 ADPKD 细胞囊肿增大的能力强于非分泌型。这些发现有助于确定未来 ADPKD 临床治疗的策略。
