Increased leucine-rich α2-glycoprotein-1 (LRG1) has been observed in various inflammatory and autoimmune diseases. We aimed to explore the expression and role of LRG1 in lupus nephritis (LN). Plasma LRG1 (pLRG1) was measured by enzyme-linked immunosorbent assay in 101 patients with renal biopsy-proven LN and 21 healthy controls (HC). Relationships between pLRG1 and clinical and pathological characteristics were analyzed. The expression of LRG1 in peripheral blood leukocytes and kidney was detected by flow cytometry, immunohistochemistry and immunofluorescence, respectively. Further cell experiments were focused on the role of LRG1. We found that LRG1 was expressed in plasma, some peripheral blood leukocytes, proximal tubule and several inflammatory cells. The levels of LRG1 in plasma, peripheral blood leukocytes and kidney were elevated in LN patients as compared to HC. Plasma expression levels of LRG1 correlated positively with renal function and renal disease activity, and reflect specific pathologic lesions in the kidneys of patients with LN. Interleukin-1β and interleukin-6, not tumor necrosis factor-α and interferon γ induced the LRG1 expression in human renal tubular epithelial cell line. Moreover, stimulation of recombinant human LRG1 could inhibit late apoptosis, promote proliferation and regulate expression of inflammatory factors and cytokines. Plasma expression levels of LRG1 were associated with renal function, disease activity, and pathology in LN. It might also be involved in renal inflammation, proliferation and apoptosis of endothelial cells. LRG1 might be a potential prognosis novel predictor in LN patients.

中文翻译：

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狼疮性肾炎患者血浆和肾脏中富含亮氨酸的α2-糖蛋白-1上调

在各种炎症和自身免疫疾病中观察到富含亮氨酸的 α2-糖蛋白-1 (LRG1) 增加。我们旨在探讨 LRG1 在狼疮性肾炎 (LN) 中的表达和作用。血浆 LRG1 (pLRG1) 通过酶联免疫吸附测定在 101 名肾活检证实的 LN 患者和 21 名健康对照 (HC) 中进行测量。分析了pLRG1与临床病理特征的关系。分别采用流式细胞术、免疫组化和免疫荧光法检测LRG1在外周血白细胞和肾脏中的表达。进一步的细胞实验集中在 LRG1 的作用上。我们发现LRG1在血浆、一些外周血白细胞、近端小管和几种炎症细胞中表达。血浆中 LRG1 的水平，与 HC 相比，LN 患者的外周血白细胞和肾脏升高。LRG1 的血浆表达水平与肾功能和肾脏疾病活动度呈正相关，并反映 LN 患者肾脏中的特定病理病变。Interleukin-1β 和 interleukin-6，而不是肿瘤坏死因子-α 和干扰素 γ 在人肾小管上皮细胞系中诱导 LRG1 表达。此外，重组人LRG1的刺激可以抑制晚期细胞凋亡，促进增殖并调节炎症因子和细胞因子的表达。LRG1 的血浆表达水平与 LN 的肾功能、疾病活动和病理相关。它还可能参与肾脏炎症、内皮细胞的增殖和凋亡。LRG1 可能是 LN 患者的潜在预后新预测因子。