Proteomic profiling of interferon-responsive reactive astrocytes in rodent and human.
Proteomic profiling of interferon-responsive reactive astrocytes in rodent and human.
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啮齿动物和人类干扰素反应性星形胶质细胞的蛋白质组学分析。
作者：
Prakash,Priya;Erdjument-Bromage,Hediye;O'Dea,MichaelR;Munson,ChristyN;Labib,David;Fossati,Valentina;Neubert,ThomasA;Liddelow,ShaneA
星形胶质细胞是中枢神经系统胶质细胞的异质群体，其通过经历称为“反应性”的转化来响应病理性损伤和损伤。反应性星形胶质细胞表现出不同的和环境依赖性的细胞，分子和功能状态变化，可以支持或干扰组织稳态。我们最近发现了一种由干扰素应答基因如Igtp、Ifit 3、Mx 1等定义的反应性星形胶质细胞亚状态，称为干扰素应答反应性星形胶质细胞（IRRA）。为了进一步定义IRRA的转录组学定义，我们希望定义这种反应性亚状态中发生的蛋白质组学变化。我们使用TNF、IL 1 α、C1 Q和IFNβ在免疫标记的啮齿动物星形胶质细胞和人iPSC分化的星形胶质细胞中诱导IRRA，并使用无偏定量蛋白质组学表征其蛋白质组学谱（细胞和分泌）。我们鉴定了2335种独特的细胞蛋白，包括IFIT 2/3、IFITM 3、OASL 1/2、MX 1/2/3和STAT 1。我们还报告说，啮齿动物和人类IRRA分泌PAI 1，丝氨酸蛋白酶抑制剂，可能会影响附近细胞的反应状态和功能。最后，我们评估了IRRA与神经毒性反应性星形胶质细胞（NRA）的区别。虽然NRA通过补体蛋白C3的表达来描述，但它在IRRA中没有上调。相反，我们发现了约90种IRRA特有的蛋白质，包括OAS 1A，IFIT 3和MX 1。星形胶质细胞中的干扰素信号传导对于抗病毒免疫应答以及调节突触可塑性和谷氨酸转运机制至关重要。IRRA如何促进这些功能尚不清楚。这项研究为未来的实验提供了基础，以确定IRRA在神经退行性疾病中的功能作用。
Astrocytes are a heterogeneous population of central nervous system glial cells that respond to pathological insults and injury by undergoing a transformation called “reactivity.” Reactive astrocytes exhibit distinct and context‐dependent cellular, molecular, and functional state changes that can either support or disturb tissue homeostasis. We recently identified a reactive astrocyte sub‐state defined by interferon‐responsive genes likeIgtp, Ifit3, Mx1, and others, called interferon‐responsive reactive astrocytes (IRRAs).To further this transcriptomic definition of IRRAs, we wanted to define the proteomic changes that occur in this reactive sub‐state. We induced IRRAs in immunopanned rodent astrocytes and human iPSC‐differentiated astrocytes using TNF, IL1α, C1Q, and IFNβ and characterized their proteomic profile (both cellular and secreted) using unbiased quantitative proteomics. We identified 2335 unique cellular proteins, including IFIT2/3, IFITM3, OASL1/2, MX1/2/3, and STAT1. We also report that rodent and human IRRAs secrete PAI1, a serine protease inhibitor which may influence reactive states and functions of nearby cells. Finally, we evaluated how IRRAs are distinct from neurotoxic reactive astrocytes (NRAs). While NRAs are described by expression of the complement protein C3, it was not upregulated in IRRAs. Instead, we found ~90 proteins unique to IRRAs not identified in NRAs, including OAS1A, IFIT3, and MX1. Interferon signaling in astrocytes is critical for the antiviral immune response and for regulating synaptic plasticity and glutamate transport mechanisms. How IRRAs contribute to these functions is unknown. This study provides the basis for future experiments to define the functional roles of IRRAs in the context of neurodegenerative disorders.