Russell Dayvia A, Van Beusecum Justin P, Markiewicz Margaret, Sanchez Sandra M, Barth Jeremy L, Oates Jim C
Medical Service, Ralph H Johnson VA Medical Center, Charleston, South Carolina, USA.
Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina, USA.
Lupus Sci Med. 2025 Jun 5;12(1):e001568. doi: 10.1136/lupus-2025-001568.
Lupus nephritis (LN) is characterised by renal endothelial dysfunction, which contributes to progressive kidney injury. Endothelial nitric oxide synthase (eNOS) plays a modulating role in LN, as genetic ablation of the eNOS enzyme worsens disease. Serum from patients with active LN induces uncoupling of eNOS homodimers, leading to superoxide (SO) rather than nitric oxide (NO) production by eNOS. This uncoupling is reversed with L-sepiapterin (L-Sep). This study was designed to further examine changes in gene expression in glomerular endothelial cells induced by LN serum and whether treatment with L-Sep can ameliorate these changes.
Primary human renal glomerular endothelial cells (HRGECs) were cultured with serum from healthy controls (HCs), patients with LN during remission (LN rem) or patients with LN during flare (LN flare) with and without L-Sep. Bulk RNA sequencing was performed on RNA isolated from cultured cells. Differential gene expression was determined, and pathway and gene enrichment analyses were performed on differentially expressed genes.
L-Sep treatment induced differential gene expression after culture in HRGECs cultured with LN flare serum. Addition of L-Sep induced genes involved in promoting endothelial function and enriched for pathways of NO biosynthetic and metabolic processes, fatty acid and lipid biosynthesis, neurotransmitter biosynthesis, reactive oxygen biosynthesis, vascular endothelial growth factor production and regulation of smooth muscle contraction.
These results indicate that glomerular endothelial cells can mount an active inflammatory response in an LN serum environment. More importantly, L-Sep modulates gene expression in a fashion consistent with reduction of oxidative stress and increased NO production. These findings provide the rationale to target endothelial dysfunction to modulate LN with L-Sep as a therapeutic.
狼疮性肾炎（LN）的特征是肾内皮功能障碍，这会导致进行性肾损伤。内皮型一氧化氮合酶（eNOS）在LN中起调节作用，因为eNOS酶的基因敲除会使疾病恶化。活动性LN患者的血清可诱导eNOS同二聚体解偶联，导致eNOS产生超氧化物（SO）而非一氧化氮（NO）。L-四氢生物蝶呤（L-Sep）可逆转这种解偶联。本研究旨在进一步研究LN血清诱导的肾小球内皮细胞基因表达变化，以及L-Sep治疗是否能改善这些变化。
将原代人肾小球内皮细胞（HRGECs）与健康对照（HCs）、缓解期LN患者（LN缓解期）或活动期LN患者（LN活动期）的血清一起培养，同时添加或不添加L-Sep。对从培养细胞中分离的RNA进行大量RNA测序。确定差异基因表达，并对差异表达基因进行通路和基因富集分析。
在用LN活动期血清培养的HRGECs中，L-Sep处理后诱导了差异基因表达。添加L-Sep可诱导参与促进内皮功能的基因，并富集于NO生物合成和代谢过程、脂肪酸和脂质生物合成、神经递质生物合成、活性氧生物合成、血管内皮生长因子产生和平滑肌收缩调节等通路。
这些结果表明，肾小球内皮细胞在LN血清环境中可引发活跃炎症反应。更重要的是，L-Sep以与降低氧化应激和增加NO产生相一致的方式调节基因表达。这些发现为将内皮功能障碍作为靶点，以L-Sep作为治疗药物来调节LN提供了理论依据。
