The role of the PD-1/PD-L1 axis in macrophage differentiation and function during pregnancy
The role of the PD-1/PD-L1 axis in macrophage differentiation and function during pregnancy
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PD-1/PD-L1轴在妊娠期巨噬细胞分化和功能中的作用
DOI：
10.1093/humrep/dey347
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发表时间：
2019-01-01
影响因子：
6.1
通讯作者：
Liao, Aihua
中科院分区：
文献类型：
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作者：
Zhang, Yonghong;Ma, Lina;Liao, Aihua
研究问题：程序性细胞死亡-1（PD-1）/PD-1配体-1（PD-L1）轴在妊娠早期巨噬细胞极化中的作用是什么？简要答复：PD-1信号是巨噬细胞分化和功能的主要调节因子，对妊娠成功至关重要。已知：具有M2表型的蜕膜巨噬细胞（DM）占优势，是妊娠早期母胎耐受的重要因素。研究设计、规模、持续时间：24例复发性流产（RM）和70例选择性终止早期正常妊娠（NP）的妇女纳入研究。包括12只雌性CBA/J、4只雄性DBA/2和4只雄性BALB/c小鼠，并进行交配。12只CBA/J孕鼠分为3组，每组4只：健康对照组CBA/ JxBALB/c，流产倾向组CBA/JxDBA/2，正常妊娠组CBA/JxBALB/c，PD-1单克隆抗体处理组。通过定量RT-PCR（qRT-PCR）和蛋白质印迹法测定人绒毛中的PD-L1表达。使用了一种由从NP患者中分离的外周血CD 14（+）单核细胞组成的体外模型。流式细胞术检测分化的巨噬细胞的形态和吞噬活性。通过qRT-PCR测定可能导致由PD-1信号传导调节的巨噬细胞极化的基因的mRNA水平。我们的体内模型中包括12只妊娠小鼠，并进行不同的治疗。通过流式细胞术分析小鼠脾脏和子宫中的胚胎吸收率、巨噬细胞谱以及PD-1表达。主要结果和机会的作用：与NP相比，RM女性的M1 DM百分比升高DM组PD-1蛋白表达明显低于对照组（P <0.05）。此外，RM患者胎盘绒毛中PD-L1的mRNA和蛋白表达水平均降低（P < 0.001）。使用体外实验，与对照组相比，我们发现重组人（rh）PD-L1 Fc（人PD-L1融合到人IgG 1的Fc区）激活PD-1可驱动具有免疫调节特性的巨噬细胞分化（P < 0.01）。而PD-1阻断可促进M1表型的优势（P < 0.01）。PD-1极化的巨噬细胞吞噬活性增强（P < 0.01），阻断PD-1后吞噬活性降低（P < 0.001）。阻断PD-1后，促炎细胞因子和干扰素调节因子（IRF）5的表达增加（P < 0.05），而IRF 4的表达受到抑制（P < 0.05）。此外，PD-1阻断剂促进巨噬细胞糖酵解（P < 0.01），抑制脂肪酸氧化（P < 0.05）。在DM代谢重编程过程中，阻断PD-1可上调磷酸肌醇3-激酶/蛋白激酶B/哺乳动物雷帕霉素靶蛋白和丝裂原活化蛋白激酶/细胞外信号调节激酶/细胞外信号调节激酶的mRNA表达水平（P < 0.05）。此外，体内小鼠数据显示PD-1阻断或缺乏与母胎界面处M2百分比降低（P < 0.05）和胚胎丢失（P < 0.05）相关。局限性，预防原因：在流产组织中观察到的DM极化的变化是否是妊娠死亡的原因或后果仍需要进一步调查。此外，还需要进行代谢物分析，以进一步测量生物能量特征。研究结果的更广泛意义：这是第一项关于PD-1/PD-L1轴在妊娠早期巨噬细胞极化中的作用的研究;这种探索增强了我们对妊娠早期生理学的理解。我们的研究还表明，靶向PD-1通路可能是预防妊娠丢失的一种新的治疗策略。
STUDY QUESTION: What is the role of the programmed cell death-1 (PD-1)/PD-1 ligand-1 (PD-L1) axis in macrophage polarization during early pregnancy?SUMMARY ANSWER: PD-1 signaling is a major regulator of macrophage differentiation and function, and it is critical for the success of a pregnancy.WHAT IS KNOWN ALREADY: The predominance of decidual macrophages (DMs) with an M2 phenotype is an important contributor to maternal-fetal tolerance during early pregnancy.STUDY DESIGN, SIZE, DURATION: Twenty-four women with recurrent miscarriage (RM) and 70 women undergoing elective termination of an early normal pregnancy (NP) were included. Twelve female CBA/J, four male DBA/2, and four male BALB/c mice were included and mating carried out. The 12 CBA/J pregnant mice were then categorized into three groups of four mice: healthy control group CBA/ JxBALB/c, abortion-prone pregnant group CBA/JxDBA/2 and normal pregnancies CBA/JxBALB/c treated with anti-PD-1 monoclonal antibodies.PARTICIPANTS/MATERIALS, SETTING, METHODS: The profile of DMs, and the expression of PD-1 and PD-L1 in DMs from women with NP and RM were measured by flow cytometry. PD-L1 expression in human villi was determined by quantitative RT-PCR (qRT-PCR) and western blot. An in vitro model consisting of peripheral CD14(+) monocytes isolated from women with NP was used. The profile of differentiated macrophages and their phagocytotic activity were then measured by flow cytometry. The mRNA levels of genes potentially underlying macrophage polarization modulated by PD-1 signaling were determined by qRT-PCR. Twelve pregnant mice were included in our in vivo model and underwent different treatment. The embryo resorption rate, and macrophage profile as well as PD-1 expression in murine spleens and uterus were analyzed by flow cytometry.MAIN RESULTS AND THE ROLE OF CHANCE: Compared with NP, women with RM had elevated percentages of M1 DMs (P < 0.01), and reduced frequencies of M2 DMs (P < 0.05), as well as decreased PD-1 protein expression (P < 0.05) in the DMs. In addition, decreased mRNA and protein levels of PD-L1 expression in placental villi were observed in women with RM (P < 0.001). Using in vitro experiments, compared to the control group, we found that PD-1 activation by recombinant human (rh) PD-L1 Fc (human PD-L1 fused to the Fc region of human IgG1) drove the differentiation of macrophages with immuno-modulatory characteristics (P < 0.01). However, PD-1 blockade promoted dominance of the M1 phenotype (P < 0.01). PD-1 polarized macrophages showed enhanced phagocytic activity (P < 0.01), which was decreased with PD-1 blockade (P < 0.001). Furthermore, PD-1 blockade promoted the expression of pro-inflammatory cytokines and interferon regulatory factor (IRF) 5 (P < 0.05), while IRF4 expression was inhibited (P < 0.05). In addition, PD-1 blockade promoted macrophage glycolysis (P < 0.01) and inhibited fatty acid oxidation (P < 0.05). The mRNA expression levels of both phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin and mitogen-activated protein kinase/extracellular signal-regulated kinase/extracellular signal-regulated kinase were upregulated (P < 0.05) with PD-1 blockade during DM metabolic reprogramming. Moreover, in vivo mice data showed that PD-1 blockade or deficiency was associated with decreased M2 percentages at the maternal-fetal interface (P < 0.05) and embryo loss (P < 0.05).LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Whether the changes in DM polarization seen in miscarriage tissues are a cause or consequence of the demise of the pregnancy still requires further investigation. In addition, conducting metabolite analysis is required to further measure bioenergetic profiles.WIDER IMPLICATIONS OF THE FINDINGS: This is the first study on the role of the PD-1/PD-L1 axis in macrophage polarization during early pregnancy; such exploration enhances our understanding of the physiology of early pregnancy. Our study also indicates that targeting the PD-1 pathway may represent a novel therapeutic strategy to prevent pregnancy loss.