Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States.
Department of Pathology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.
Front Immunol. 2019 Apr 2;10:578. doi: 10.3389/fimmu.2019.00578. eCollection 2019.
and both contain risk alleles for systemic lupus erythematosus (SLE) and Sjögren's syndrome (pSS). The former escapes X inactivation. Our group predicts specific endolysosomal-dependent immune responses are driven by the protein products of these genes, which form a complex at the endolysosomal surface. Our previous studies have shown that knocking out increases lysosomal pH in female monocytes, and the present study assesses whether the lysosomal pH in 46,XX women, who overexpress CXorf21 in monocytes, B cells, and dendritic cells (DCs), differs from 46,XY men. To determine endolysosome compartment pH we used both LysoSensor™ Yellow/Blue DND-160 and pHrodo® Red AM Intracellular pH Indicator in primary monocyte, B cells, DCs, NK cells, and T cells from healthy men and women volunteers. Compared to male samples, female monocytes, B cells, and DCs had lower endolysosomal pH (female/male pH value: monocytes 4.9/5.6 < 0.0001; DCs 4.9/5.7 = 0.044; B cells 5.0/5.6 < 0.05). Interestingly, T cells and NK cells, which both express low levels of CXorf21, showed no differential pH levels between men and women. We have previously shown that subjects with two or more X-chromosomes have increased CXorf21 expression in specific primary immune cells. Moreover, knockdown of CXorf21 increases lysosomal pH in female monocytes. The present data show that female monocytes, DC, B cells, where CXorf21 is robustly expressed, have lower lysosomal pH compared to the same immune cell populations from males. The lower pH levels observed in specific female immune cells provide a function to these SLE/SS-associated genes and a mechanism for the reported inflated endolysosomal-dependent immune response observed in women compared to men (i.e., TLR7/type I Interferon activity).
并且两者都包含系统性红斑狼疮（SLE）和干燥综合征（pSS）的风险等位基因。前者逃避 X 染色体失活。我们的研究小组预测，这些基因的蛋白质产物会引发特定的内溶酶体依赖性免疫反应，这些蛋白质在溶酶体表面形成复合物。我们之前的研究表明，敲除 会增加女性单核细胞中的溶酶体 pH 值，本研究评估了在单核细胞、B 细胞和树突状细胞（DC）中过度表达 CXorf21 的 46,XX 女性与 46,XY 男性之间的溶酶体 pH 值是否存在差异。为了确定内溶酶体隔室 pH 值，我们使用 LysoSensor™ Yellow/Blue DND-160 和 pHrodo® Red AM 细胞内 pH 指示剂，检测了来自健康男性和女性志愿者的原代单核细胞、B 细胞、DC、NK 细胞和 T 细胞。与男性样本相比，女性单核细胞、B 细胞和 DC 的内溶酶体 pH 值较低（女性/男性 pH 值：单核细胞 4.9/5.6 < 0.0001；DC 4.9/5.7 = 0.044；B 细胞 5.0/5.6 < 0.05）。有趣的是，表达低水平 CXorf21 的 T 细胞和 NK 细胞在男性和女性之间没有表现出不同的 pH 值水平。我们之前已经表明，具有两条或更多 X 染色体的个体在特定的原代免疫细胞中具有更高的 CXorf21 表达。此外，CXorf21 的敲低会增加女性单核细胞中的溶酶体 pH 值。本研究数据显示，与男性相同的免疫细胞群体相比，CXorf21 表达丰富的女性单核细胞、DC 和 B 细胞的溶酶体 pH 值较低。在特定的女性免疫细胞中观察到的较低 pH 值水平为这些与 SLE/SS 相关的基因提供了功能，并为与男性相比女性中报道的膨胀的内溶酶体依赖性免疫反应提供了一种机制（即 TLR7/Ⅰ型干扰素活性）。
