DataSheet_1_Reduced expressions of apoptosis-related proteins TRAIL, Bcl-2, and TNFR1 in NK cells of juvenile-onset systemic lupus erythematosus patients: relations with disease activity, nephritis, and neuropsychiatric involvement.pdf

BackgroundLupus pathogenesis is mainly ascribed to increased production and/or impaired clearance of dead cell debris. Although self-reactive T and B lymphocytes are critically linked to lupus development, neutrophils, monocytes, and natural killer (NK) cells have also been implicated. This study assessed apoptosis-related protein expressions in NK cells of patients with juvenile-onset systemic lupus erythematosus (jSLE) and relations to disease activity parameters, nephritis, and neuropsychiatric involvement.
MethodsThirty-six patients with jSLE, 13 juvenile dermatomyositis (JDM) inflammatory controls, and nine healthy controls had Fas, FasL, TRAIL, TNFR1, Bcl-2, Bax, Bim, and caspase-3 expressions in NK cells (CD3−CD16+CD56+) simultaneously determined by flow cytometry. Disease activity parameters included Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score, erythrocyte sedimentation rate, C-reactive protein level, anti-double strain DNA antibody level, complement fractions C3 and C4 levels.
ResultsPatients with jSLE had a profile of significantly reduced expression of TRAIL, Bcl-2, and TNFR1 proteins in NK cells when compared to healthy controls. Similar profile was observed in patients with jSLE with active disease, positive anti-dsDNA, nephritis, and without neuropsychiatric involvement. Patients with jSLE with positive anti-dsDNA also had reduced expression of Bax in NK cells when compared healthy controls and to those with negative anti-dsDNA. Yet, patients with jSLE with negative anti-dsDNA had reduced mean fluorescence intensity (MFI) of Bim in NK cells compared to healthy controls. Patients with jSLE with nephritis also had reduced MFI of Fas in NK cells when compared to those without nephritis. In addition, in patients with jSLE, the proportion of FasL-expressing NK cells directly correlated with the SLEDAI-2K score (rs = 0.6, p = 0.002) and inversely correlated with the C3 levels (rs = −0.5, p = 0.007). Moreover, patients with jSLE had increased NK cell percentage and caspase-3 protein expression in NK cells when compared to JDM controls.
ConclusionThis study extends to NK cells an altered profile of TRAIL, Bcl-2, TNFR1, Fas, FasL, Bax, Bim, and caspase-3 proteins in patients with jSLE, particularly in those with active disease, positive anti-dsDNA, nephritis, and without neuropsychiatric involvement. This change in apoptosis-related protein expressions may contribute to the defective functions of NK cells and, consequently, to lupus development. The full clarification of the role of NK cells in jSLE pathogenesis may pave the way for new therapies like those of NK cell–based.

背景：狼疮的发病机制主要归因于细胞死亡碎片的产生增多和/或清除受损。尽管自身反应性T、B淋巴细胞与狼疮发病密切相关，但中性粒细胞、单核细胞以及自然杀伤细胞（natural killer cells）也被认为与该病的发生发展有关。本研究检测了青少年起病的系统性红斑狼疮（juvenile-onset systemic lupus erythematosus, jSLE）患者NK细胞中凋亡相关蛋白的表达水平，并分析其与疾病活动度指标、肾炎及神经精神受累的相关性。
方法：本研究采用流式细胞术同步检测了36例jSLE患者、13例青少年皮肌炎（juvenile dermatomyositis, JDM）炎症对照组患者及9例健康对照者的NK细胞（CD3⁻CD16⁺CD56⁺）中Fas、FasL、TRAIL、TNFR1、Bcl-2、Bax、Bim及半胱天冬酶-3（caspase-3）的表达水平。疾病活动度指标包括系统性红斑狼疮疾病活动指数2000（Systemic Lupus Erythematosus Disease Activity Index 2000, SLEDAI-2K）评分、红细胞沉降率、C反应蛋白水平、抗双链DNA抗体水平及补体C3、C4水平。
结果：与健康对照组相比，jSLE患者NK细胞中TRAIL、Bcl-2及TNFR1蛋白的表达水平显著降低。在疾病活动、抗dsDNA阳性、合并肾炎且无神经精神受累的jSLE患者中，也观察到了类似的表达谱改变。与健康对照组及抗dsDNA阴性的jSLE患者相比，抗dsDNA阳性的jSLE患者NK细胞中Bax的表达水平也有所降低。然而，与健康对照组相比，抗dsDNA阴性的jSLE患者NK细胞中Bim的平均荧光强度（mean fluorescence intensity, MFI）有所降低。合并肾炎的jSLE患者NK细胞中Fas的MFI也较无肾炎患者更低。此外，在jSLE患者中，表达FasL的NK细胞比例与SLEDAI-2K评分呈正相关（rs=0.6，p=0.002），与C3水平呈负相关（rs=-0.5，p=0.007）。除此之外，与JDM对照组相比，jSLE患者的NK细胞占比及NK细胞中caspase-3的蛋白表达水平均升高。
结论：本研究明确了jSLE患者NK细胞中TRAIL、Bcl-2、TNFR1、Fas、FasL、Bax、Bim及caspase-3蛋白的表达谱异常，该异常在疾病活动、抗dsDNA阳性、合并肾炎且无神经精神受累的患者中尤为显著。凋亡相关蛋白的表达改变可能导致NK细胞功能缺陷，进而参与狼疮的发病过程。全面阐明NK细胞在jSLE发病机制中的作用，有望为基于NK细胞的新型治疗方案开辟道路。