Abstract：
BACKGROUND: Complement activation may facilitate hypertension through its effects on immune responses. The anaphylatoxin C5a, a major inflammatory effector, binds to the C5a receptor 1 and 2 (C5aR1, C5aR2). We have recently shown that C5aR1-/- mice have reduced hypertensive renal injury. The role of C5aR2 in hypertension is unknown.
METHODS: For examination of C5aR2 expression on infiltrating and resident renal cells a tandem dye Tomato-C5aR2 knock-in reporter mouse was used. Human C5aR2 expression was analyzed in a single cell RNAseq data set from kidneys of hypertensive patients. Finally, we examined the effect of Ang II induced hypertension in C5aR2-deficient mice.
RESULTS: Flow cytometric analysis of leukocytes isolated from kidneys of the reporter mice showed that dendritic cells are the major C5aR2-expressing population (34%) followed by monocyte/macrophages (30%) and neutrophils (14%). Using confocal microscopy C5aR2 was not detected in resident renal or cardiac cells. In the human kidney C5aR2 was also mainly found in monocytes, macrophages and dendritic cells with a significantly higher expression in hypertension (p<0,05). Unilateral nephrectomy was performed followed by infusion of Ang II (0.75 ng/g/min) and a high salt diet in wildtype (n=18) and C5aR2-deficient mice (n=14). Blood pressure, renal injury (albuminuria, glomerular filtration rate, glomerular and tubulointerstitial injury, inflammation) and cardiac injury (cardiac fibrosis, heart weight, gene expression) did not differ between hypertensive wildtype and C5aR2-/- mice.
CONCLUSIONS: In summary, C5aR2 is mainly expressed on myeloid cells in the kidney in mice and humans but its deficiency has no effect in Ang II induced hypertensive injury.
METHODS: For examination of C5aR2 expression on infiltrating and resident renal cells a tandem dye Tomato-C5aR2 knock-in reporter mouse was used. Human C5aR2 expression was analyzed in a single cell RNAseq data set from kidneys of hypertensive patients. Finally, we examined the effect of Ang II induced hypertension in C5aR2-deficient mice.
RESULTS: Flow cytometric analysis of leukocytes isolated from kidneys of the reporter mice showed that dendritic cells are the major C5aR2-expressing population (34%) followed by monocyte/macrophages (30%) and neutrophils (14%). Using confocal microscopy C5aR2 was not detected in resident renal or cardiac cells. In the human kidney C5aR2 was also mainly found in monocytes, macrophages and dendritic cells with a significantly higher expression in hypertension (p<0,05). Unilateral nephrectomy was performed followed by infusion of Ang II (0.75 ng/g/min) and a high salt diet in wildtype (n=18) and C5aR2-deficient mice (n=14). Blood pressure, renal injury (albuminuria, glomerular filtration rate, glomerular and tubulointerstitial injury, inflammation) and cardiac injury (cardiac fibrosis, heart weight, gene expression) did not differ between hypertensive wildtype and C5aR2-/- mice.
CONCLUSIONS: In summary, C5aR2 is mainly expressed on myeloid cells in the kidney in mice and humans but its deficiency has no effect in Ang II induced hypertensive injury.
摘要：
背景：补体激活可能通过其对免疫反应的影响促进高血压。过敏毒素C5a,一个主要的炎症效应，与C5a受体1和2(C5aR1,C5aR2)结合。我们最近证明C5aR1-/-小鼠具有减少的高血压肾损伤。C5aR2在高血压中的作用尚不清楚。
方法:为了检查浸润和驻留肾细胞上的C5aR2表达,使用串联染料番茄-C5aR2敲入报告小鼠。在来自高血压患者肾脏的单细胞RNAseq数据集中分析人C5aR2表达。最后,我们研究了AngII诱导的高血压对C5aR2缺陷小鼠的影响。
结果:从报告小鼠的肾分离的白细胞的流式细胞术分析显示,树突细胞是主要的C5aR2表达群体(34%),随后是单核细胞/巨噬细胞(30%)和嗜中性粒细胞(14%)。使用共聚焦显微镜在常驻肾或心脏细胞中未检测到C5aR2。在人类肾脏中，C5aR2也主要存在于单核细胞中，巨噬细胞和树突状细胞在高血压中的表达明显更高（p<0.05）。在野生型（n=18）和C5aR2缺陷型小鼠（n=14）中进行单侧肾切除术，然后输注AngII（0.75ng/g/min）和高盐饮食。血压,肾损伤（蛋白尿，肾小球滤过率,肾小球和肾小管间质损伤，炎症)和心脏损伤(心脏纤维化，心脏重量,基因表达）在高血压野生型和C5aR2-/-小鼠之间没有差异。
结论：总之，C5aR2主要在小鼠和人类肾脏的髓系细胞上表达，但其缺乏对AngII引起的高血压损伤没有影响。
方法:为了检查浸润和驻留肾细胞上的C5aR2表达,使用串联染料番茄-C5aR2敲入报告小鼠。在来自高血压患者肾脏的单细胞RNAseq数据集中分析人C5aR2表达。最后,我们研究了AngII诱导的高血压对C5aR2缺陷小鼠的影响。
结果:从报告小鼠的肾分离的白细胞的流式细胞术分析显示,树突细胞是主要的C5aR2表达群体(34%),随后是单核细胞/巨噬细胞(30%)和嗜中性粒细胞(14%)。使用共聚焦显微镜在常驻肾或心脏细胞中未检测到C5aR2。在人类肾脏中，C5aR2也主要存在于单核细胞中，巨噬细胞和树突状细胞在高血压中的表达明显更高（p<0.05）。在野生型（n=18）和C5aR2缺陷型小鼠（n=14）中进行单侧肾切除术，然后输注AngII（0.75ng/g/min）和高盐饮食。血压,肾损伤（蛋白尿，肾小球滤过率,肾小球和肾小管间质损伤，炎症)和心脏损伤(心脏纤维化，心脏重量,基因表达）在高血压野生型和C5aR2-/-小鼠之间没有差异。
结论：总之，C5aR2主要在小鼠和人类肾脏的髓系细胞上表达，但其缺乏对AngII引起的高血压损伤没有影响。
