Institute for Maternal and Child Health I.R.C.C.S. Burlo Garofolo, Trieste, Italy.
Renal Unit, Department of Medicine, University Hospital of Verona, Verona, Italy.
Clin Transl Sci. 2021 May;14(3):964-975. doi: 10.1111/cts.12961. Epub 2021 Jan 25.
To assess whether NLRP3 gene promoter methylation was able to discriminate glucocorticoid (GC)-resistant from GC-sensitive idiopathic nephrotic syndrome (INS), patients with minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS), we measured the methylation level of NLRP3 promoter in DNA from peripheral blood cells of 10 adult patients with GC-resistant FSGS already in hemodialysis and 18 patients with GC-sensitive INS (13 MCD/5 FSGS) and in 21 pediatric patients with INS with MCD/FSGS before starting any treatment. Association of NLRP3 inflammasome with GC resistance was recapitulated in vitro in monocytic cell lines (THP-1 and U937). In both adults and pediatric patients, NLRP3 promoter methylation was significantly reduced in GC-resistant compared with GC-sensitive patients. Indeed, NLRP3 methylation distinguished GC-resistant and GC-sensitive patients (area under the receiver operating characteristic curve [AUROC] 86.7% in adults, p = 0.00019, and 73.5% in children, p = 0.00097). NLRP3 knock-down augmented sensitivity to GCs in THP-1 cells, whereas NLRP3 inflammasome activation lowered GC receptor concentration, increasing GC resistance in U937 cells. Our results uncovered a new biological mechanism by which patients with INS may acquire GC resistance, that could be used in future as a novel noninvasive diagnostic tool. Study Highlights WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC? ☑ Approximately 80% of patients with idiopathic nephrotic syndrome (INS) respond to glucocorticoids, with the remaining 20% being steroid-resistant. WHAT QUESTION DID THIS STUDY ADDRESS? ☑ Whether NLRP3 gene promoter methylation was able to discriminate glucocorticoid-resistant from glucocorticoid (GC)-sensitive INS. WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE? ☑ In both adults and children, NLRP3 promoter methylation was significantly reduced in leukocytes of patients with GC-resistant compared with GC-sensitive INS. NLRP3 inflammasome activation lowered GC receptor concentration and augmented GC resistance, whereas NLRP3 knockdown increased sensitivity to GCs in cell lines representative of monocytes (U937 and THP1). HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE? ☑ Our findings uncovered a new biological mechanism whereby patients with INS may develop resistance to GCs that could be used in the future as a novel noninvasive diagnostic tool.
为了评估 NLRP3 基因启动子甲基化是否能够区分糖皮质激素（GC）耐药和 GC 敏感的特发性肾病综合征（INS）、微小病变疾病（MCD）或局灶节段性肾小球硬化症（FSGS）患者，我们测量了外周血白细胞中 NLRP3 启动子的甲基化水平在 10 名已进行血液透析的 GC 耐药 FSGS 成年患者和 18 名 GC 敏感 INS 患者（13 名 MCD/5 名 FSGS）以及 21 名儿科 INS 患者（MCD/FSGS）中，这些患者在开始任何治疗之前。NLRP3 炎性小体与 GC 耐药的关联在单核细胞系（THP-1 和 U937）中得到了重现。在成年患者和儿科患者中，与 GC 敏感患者相比，GC 耐药患者的 NLRP3 启动子甲基化明显降低。事实上，NLRP3 甲基化可以区分 GC 耐药和 GC 敏感的患者（成年患者的受试者工作特征曲线下面积[AUROC]为 86.7%，p=0.00019，儿童患者为 73.5%，p=0.00097）。NLRP3 敲低增强了 THP-1 细胞对 GCs 的敏感性，而 NLRP3 炎性小体的激活降低了 GC 受体浓度，增加了 U937 细胞对 GCs 的耐药性。我们的研究结果揭示了一种新的生物学机制，即 INS 患者可能获得 GC 耐药性，这可能在未来被用作一种新的非侵入性诊断工具。研究亮点关于这个话题，目前的知识是什么？☑大约 80%的特发性肾病综合征（INS）患者对糖皮质激素有反应，其余 20%的患者为糖皮质激素耐药。这项研究提出了什么问题？☑NLRP3 基因启动子甲基化是否能够区分糖皮质激素耐药和糖皮质激素（GC）敏感的 INS。这项研究为我们的知识增加了什么？☑与 GC 敏感的 INS 患者相比，GC 耐药的 INS 患者白细胞中的 NLRP3 启动子甲基化明显降低。NLRP3 炎性小体的激活降低了 GC 受体浓度并增强了 GC 耐药性，而 NLRP3 敲低则增加了细胞系中单核细胞（U937 和 THP1）对 GCs 的敏感性。这将如何改变临床药理学或转化科学？☑我们的发现揭示了一种新的生物学机制，即 INS 患者可能会对 GCs 产生耐药性，这可能在未来被用作一种新的非侵入性诊断工具。
