常染色体显性多囊肾病(ADPKD),最常见的遗传性肾病,受不同形式的细胞死亡调节,包括细胞凋亡和自噬。然而,在铁性凋亡的ADPKD中的作用,一种最近发现的由铁和脂质代谢介导的细胞死亡形式,仍然难以捉摸。
为了确定铁性凋亡在ADPKD中的病理生理作用,我们研究了Pkd1(编码多囊素-1)的缺失是否影响了铁死亡过程中关键因子的表达,使用Westernblot和qRT-PCR分析Pkd1突变肾细胞和组织。我们还检查了是否用erastin治疗,铁性凋亡诱导物,和铁沉积抑制剂铁染色-1,影响Pkd1突变小鼠模型中的囊肿生长。
我们发现缺乏Pkd1的肾细胞和组织表现出广泛的代谢异常,包括系统Xc-氨基酸反转运蛋白的表达减少(对于胱氨酸的进口至关重要),铁出口国(亚铁运输),和GPX4(铁凋亡的关键和负调节因子)。异常还包括铁导入体(TfR1,DMT1)和HO-1的表达增加,这反过来又导致铁水平升高,低GSH和GPX4活性,增加脂质过氧化,和铁性凋亡倾向。我们进一步发现erastin增加,和铁抑制素-1抑制Pkd1突变小鼠肾脏中的铁细胞死亡和Pkd1缺陷细胞的增殖。Pkd1缺陷细胞中脂质过氧化产物增加,4HNE,通过激活Akt促进存活的Pkd1突变细胞的增殖,S6、Stat3和Rb在铁过程中,有助于囊肿生长。
这些发现表明铁性凋亡有助于ADPKD进展,铁性凋亡的管理可能是ADPKD治疗的新策略。
Autosomal dominant polycystic kidney disease (ADPKD), the most common inherited kidney disease, is regulated by different forms of cell death, including apoptosis and autophagy. However, the role in ADPKD of ferroptosis, a recently discovered form of cell death mediated by iron and lipid metabolism, remains elusive.
To determine a pathophysiologic role of ferroptosis in ADPKD, we investigated whether the absence of Pkd1 (encoding polycystin-1) affected the expression of key factors involved in the process of ferroptosis, using Western blot and qRT-PCR analysis in Pkd1 mutant renal cells and tissues. We also examined whether treatment with erastin, a ferroptosis inducer, and ferrostain-1, a ferroptosis inhibitor, affected cyst growth in Pkd1 mutant mouse models.
We found that kidney cells and tissues lacking Pkd1 exhibit extensive metabolic abnormalities, including reduced expression of the system Xc- amino acid antiporter (critical for import of cystine), of iron exporter (ferroportin), and of GPX4 (a key and negative regulator of ferroptosis). The abnormalities also include increased expression of iron importers (TfR1, DMT1) and HO-1, which in turn result in high iron levels, low GSH and GPX4 activity, increased lipid peroxidation, and propensity to ferroptosis. We further found that erastin increased, and ferrostatin-1 inhibited ferroptotic cell death and proliferation of Pkd1-deficient cells in kidneys from Pkd1 mutant mice. A lipid peroxidation product increased in Pkd1-deficient cells,
4HNE, promoted the proliferation of survived Pkd1 mutant cells via activation of Akt, S6, Stat3, and Rb during the ferroptotic process, contributing to cyst growth.
These findings indicate that ferroptosis contributes to ADPKD progression and management of ferroptosis may be a novel strategy for ADPKD treatment.