S1PR1介导的IFNAR1降解可以调节浆细胞样树突状细胞α-干扰素的自动扩增-USB迷|专注于互联网分享

2024年2月23日发(作者：祈晓夏)

S1PR1-mediated IFNAR1 degradation modulates plasmacytoid

dendritic cell interferon-α autoamplification

由S1PR1介导的IFNAR1降解可以调节浆细胞样树突状细胞

α-干扰素的自动扩增／信号放大

摘要：

Blunting immunopathology without abolishing host defense is the foundation for safe

and effective modulation of infectious and autoimmune diseases.

没有废除宿主防御机制的免疫病理钝化是安全、有效调节传染病和自身免疫性疾病的基础。

Sphingosine 1-phosphate receptor 1 (S1PR1) agonists are effective in treating

infectious and multiple autoimmune pathologies; however, mechanisms underlying

their clinical efficacy are yet to be fully elucidated.

1-磷酸-鞘氨醇受体1（S1PR1）促效药对于治疗传染病和多种自身免疫性疾病是有效的，然而，其临床疗效的具体机制尚未被完全阐明。

Here, we uncover an unexpected mechanism of convergence between S1PR1 and

interferon alpha receptor 1 (IFNAR1) signaling pathways.

在本研究中，我们意外发现S1PR1与α-干扰素受体1（IFNAR1）信号通路之间的趋同／聚集机制。

Activation of S1PR1 signaling by pharmacological tools or endogenous ligand

sphingosine-1 phosphate (S1P) inhibits type 1 IFN responses that exacerbate

numerous pathogenic conditions.

通过药理作用或内源性配体1-磷酸-鞘氨醇（S1P）发出信号激活S1PR1可以抑制1型干扰素应答，这将提供大量致病条件。

Mechanistically, S1PR1 selectively suppresses the type I IFN autoamplification loop in

plasmacytoid dendritic cells (pDCs), a specialized DC subset, for robust type I IFN

release.

机械地说，S1PR1能够选择性抑制1型干扰素在浆细胞样树突状细胞（pDCs，一种特殊的树突状细胞亚群，可以释放大量1型干扰素）内的自身扩增循环。

S1PR1 agonist suppression is pertussis toxin-resistant, but inhibited by an S1PR1 C-terminal–derived transactivating transcriptional activator (Tat)-fusion peptide that

blocks receptor internalization.

抗百日咳毒素可以抑制S1PR1促效药，但是是通过一个来自S1PR1 C末端的反式

激活转录活化因子Tat-融合肽（可以封闭受体内化作用）来发挥抑制作用的。

S1PR1 agonist treatment accelerates turnover of IFNAR1, suppresses signal transducer

and activator of transcription 1 (STAT1) phosphorylation, and down-modulates total

STAT1 levels, thereby inactivating the autoamplification loop.

S1PR1促效药的治疗机制是加速IFNAR1的循环，抑制转录信号转导器和活化剂1（STAT1）的磷酸化作用，以及下调总的STAT1水平，从而达到抑制自身扩增循环的效果。

Inhibition of S1P-S1PR1 signaling in vivo using the selective antagonist Ex26

significantly elevates IFN-α production in response to CpG-A.

使用选择性拮抗剂Ex26来抑制体内的S1P-S1PR1信号可以显著提升在应答CpG-A时α-干扰素的产量。

Thus, multiple lines of evidence demonstrate that S1PR1 signaling sets the sensitivity

of pDC amplification of IFN responses, thereby blunting pathogenic immune responses.

因此，大量证据表明S1PR1信号可以调节pDC放大干扰素应答的敏感性，从而钝化致病性免疫应答。

These data illustrate a lipid G-protein coupled receptor (GPCR)-IFNAR1 regulatory loop

that balances effective and detrimental immune responses and elevated en- dogenous

S1PR1 signaling.

这些数据表明一个脂质G蛋白偶联受体（GPCR）-IFNAR1调控循环能够平衡有效的和有害的免疫应答以及增加的内源性S1PR1信号。

This mechanism will likely be advantageous in individuals subject to a range of

inflammatory conditions.

这种机制可能会导致个体陷入一系列炎症状态中。

关键词：

sphingosine 1-phosphate | S1PR1 | plasmacytoid dendritic cell | interferon-α | IFNAR1

1-磷酸-鞘氨醇；1-磷酸-鞘氨醇受体1；浆细胞样树突状细胞；α-干扰素；α-干扰素受体1

前言：

Plasmacytoid dendritic cells (pDCs) are a rare innate immune cell population in mice

known for their ability to produce large quantities of type 1 IFN (IFN-I) following

stimulation with viral or cellular nucleic acids.

小鼠体内的pCDs是一种罕见的天然免疫细胞群，在病毒或细胞内核酸的刺激它能够产生大量IFN-1。

Moreover, IFN-α signaling promotes autoimmune (1), viral (2–5), and bacterial disease

pathogenesis (6).

此外，IFN-α信号可以促进自身免疫、病毒性和细菌性疾病的发病机理。

Suppression of IFN-α signaling has demonstrated efficacy in multiple autoimmune

mouse models (7–9) and during influenza viral infection (4, 10); however, the

mechanism by which sphingosine 1-phosphate receptor 1 (S1PR1) signaling prevents

IFN-α amplification during these disease states is currently unknown.

IFN-α的抑制作用已经在多种自身免疫小鼠模型的疗效和在流感病毒感染期间被阐明，然而在这些发病状态中S1PR1信号阻止IFN-α自动扩增的机制尚不清楚。

Recently, we found direct evidence that IFN-I induction and the concomitant cytokine

storm were chemically tractable using sphingosine 1-phosphate receptor 1 (S1PR1)

selective agonists.

最近，我们发现了使用S1PR1选择性促效药可以诱导IFN-I并且伴随着的细胞因子增加的直接证据。

S1PR1 agonist therapy suppressed innate immune cell recruitment and cytokine-chemokine production and improved survival without postponing viral clearance,

indicating that cytokine storm was causative of disease pathogenesis and that S1P

agonist therapy could suppress detrimental innate immune responses without

hindering virus control (10, 11).

S1PR1促效药疗法可以抑制天然免疫细胞的补充和细胞因子、趋化因子的产生，可以在没有延迟清除病毒的情况下提高存活率，这表明细胞因子的增加是疾病发病机理的原因，也表明在没有妨碍控制病毒的情况下S1P促效药疗法能够抑制有害的天然免疫应答。

The identification that S1PR1 agonists suppress detrimental innate immune responses

indicates that S1PR1 probes may serve as viable drug leads to curb resulting immune

pathology during both infectious and autoimmune disease states.

S1PR1促效药抑制有害的天然免疫应答的证实表明在传染性和自身免疫性疾病状态期间S1PR1探针作为有效药物引导控制免疫病理学结果。

The goal of the current study was to generate a detailed mechanistic understanding of

how S1PR1 selectively suppresses type I IFN and cytokine amplification.

当前的研究目的是阐明这种详细机制——S1PR1如何选择性抑制1型干扰素和细胞因子的自动扩增。

Within this study, we demonstrate that S1PR1 signaling limits the IFN-α

autoamplification loop in pDCs.

在本研究中，我们发现S1PR1信号能够限制IFN-α在pDCs内的自身扩增循环。

S1PR1 agonist suppression is pertussis toxin (PT)-resistant, but it is inhibited by an

S1PR1 C-terminal–derived transactivating transcriptional activator (Tat)-fusion

peptide that blocks receptor internalization.

抗百日咳毒素可以抑制S1PR1促效药，但是是通过一个来自S1PR1 C末端的反式激活转录活化因子Tat-融合肽（可以封闭受体内化作用）来发挥抑制作用的。

S1PR1 agonist treatment accelerates turnover of interferon alpha receptor 1 (IFNAR1),

suppresses signal transducer and activator of transcription 1 (STAT1) phosphorylation,

and down- modulates total STAT1 levels, thereby inactivating the autoamplifi- cation

loop.

Inhibition of S1P-S1PR1 signaling in vivo using the selective antagonist Ex26

significantly elevates IFN-α production in response to CpG-A.

使用选择性拮抗剂Ex26来抑制体内的S1P-S1PR1信号可以显著提升在应答CpG-A时α-干扰素的产量。

Thus, multiple lines of evidence demonstrate that S1PR1 signaling sets the sensitivity

of pDC amplification of IFN responses, thereby blunting pathogenic immune responses.

因此，大量证据表明S1PR1信号可以调节pDC放大干扰素应答的敏感性，从而钝化致病性免疫应答。

Significance本文的意义：

The sphingosine 1-phosphate receptor (S1PR1) is known to act by multiple

mechanisms: limiting lymphocyte egress from secondary lymphoid organs,

suppressing proinflammatory endothelial cell function, and acting directly on neurons

and astrocytes.

目前的研究表明S1PR1可通过多种机制发挥作用：限制淋巴细胞从次级淋巴器官

外流；抑制促炎症反应上皮细胞的功能；在神经元和星形胶质细胞上直接发挥作用。

Here, we report that sphingosine 1-phosphate (S1P)-S1PR1 signaling in plasmacytoid

dendritic cells (pDCs) directly inhibits IFN-α autoamplification by induced degradation

of the interferon alpha receptor 1 (IFNAR1) receptor and suppression of signal

transducer and activator of transcription 1 (STAT1) signaling.

在本研究中，我们发现S1P-S1PR1信号在pDCs内通过诱导IFNAR1降解和抑制STAT1信号来直接抑制IFN-α的自动扩增。

An endosomal regulatory interaction of a lipid G-protein coupled receptor (GPCR) and

IFNAR1 balances effective and detrimental components of immune responses and

provides a previously unidentified pathway that contributes to significant and

unexpected efficacy in clinical trials in multiple sclerosis, ulcerative colitis, psoriasis,

and likely other diseases with aberrant IFN-α signatures.

GPCR和IFNAR1的一种胞内调节作用能够平衡有效的和有害的免疫应答成分，也能够提供一条之前在多种细胞硬化、溃疡性结肠炎、牛皮癣以及其他可能的有IFN-α迷乱特质的疾病的临床试验当中发挥显著和意外疗效的未知途径。

Results结果：

To understand how S1PR1 signaling regulates IFN-α and cytokine amplification, we

assessed the pulmonary cell subsets that produce IFN-α and cytokines/chemokines

following influenza virus challenge.

为了理解S1PR1信号是如何调控IFN-α和细胞因子的扩增，我们拿肺部细胞亚群（该细胞群在流感病毒的挑战下可以产生IFN-α和细胞因子或趋化因子）进行试验。

Although many cell types produce IFN-α following virus infection, two major

pulmonary cell populations make significant quantities of IFN-α in vivo following

respiratory virus infection, alveolar macrophages and pDCs (11); thus, we initially

focused on these populations.

尽管当病毒感染机体时很多类型的细胞都可以产生IFN-α，但是两种主要的肺部细胞群——肺泡巨噬细胞和pCDs随着呼吸到病毒的感染可以在体内产生大量IFN-α；因此，我们一开始就关注到这两种细胞群。

We depleted pDCs from mice before influenza virus challenge.

在感染流感病毒前，我们将小鼠的pCDs敲除。

Depletion of pDCs before influenza virus challenge significantly reduced IFN-α levels

following influenza virus infection, as well as CCL2, CCL5, and IL-6 levels (Fig. S1).

这些在感染病毒前就敲除pCDs的小鼠在感染流感病毒后产生的IFN-α明显减少，CCL2、CCL5和IL-6也减少了。

We asked whether treatment of fluorescence-activated cell sorter (FACS)–purified

pDCs (>90%) from the spleen or lung with the selective S1PR1 agonist CYM-5442 (Table

1) could inhibit the production of IFN-α following stimulation with influenza virus in

vitro.

我们提出一个问题：是否经荧光激活细胞分离法（FACS，即流式细胞分选法）纯化的来自脾和肺的pDCs（>90%）由于选择性S1PR1促效药CYM-5442的作用当流感病毒在体外刺激时抑制IFN-α的产生。

Infection of pDCs with influenza virus followed by CYM-5442 treatment resulted in the

inhibition of IFN-α production (Fig. 1A) at an IC50 of 1.4 μM, as well as an IC50 of 500

nM using the highly potent S1PR1 agonist RP-001 (11), demonstrating direct inhibition

of IFN-α production from pDCs by S1PR1 agonists.

感染流感病的pCDs在CYM-5442的治疗作用下导致IFN-α的产生受到抑制（半数抑制浓度为1.4 μM或在高效S1PR1促效药作用下半数抑制浓度为500 nM），这表明S1PR1促效药可以直接抑制IFN-α的产生。

Interestingly, the IC50 of S1PR1 agonist CYM-5442 required to inhibit IFN-α

amplification exceeds the IC50 required to activate Gi/Go signaling, suggesting a non–Gi/Go-mediated mechanism for the suppression.

有趣的是要求抑制IFN-α的自动扩增的CYM-5442的IC50 超过了要求活化Gi/Go信号的IC50，这表明抑制机制不需要Gi/Go介导。

The expression of S1PR1 has not been reported in pDCs; thus, we assessed whether

S1PR1 could be detected on pDCs purified from lung and spleen.

尚未报道pCDs上能表达S1PR1；因此我们想是否可以在纯化过的来自脾和肺的pDCs检测到S1PR1。

Using the S1PR1-EGFP mice described previously (11), we determined that FACS-purified pDCs (CD11cint, B220+, PDCA-1+, and Siglec H+) expressed significant levels of

S1PR1 as determined by detection of S1PR1-EGFP by flow cytometry and

immunoblotting (Fig. S2).

用之前提到的S1PR1-EGFP小鼠做实验材料，我们通过用流式细胞技术和免疫印记法测定S1PR1-EGFP来测定经FACS纯化过的pCDs（CD11cint、B220+、PDCA-1+、

和Siglec H+）表达S1PR1的水平。

These data demonstrate that CYM-5442 suppression of cytokine amplification during

influenza virus challenge correlates with S1PR1 expression in pDCs.

这些数据表明在流感病毒感染期间CYM-5442抑制细胞因子自动扩增与S1PR1在pCDs中的表达有关系。