Nox2-Mediated PI3K and Cofilin Activation Confers Alternate Redox Control of Macrophage Pinocytosis
Nox2-Mediated PI3K and Cofilin Activation Confers Alternate Redox Control of Macrophage Pinocytosis
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DOI：
10.1089/ars.2016.6639
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发表时间：
2017-06-01
影响因子：
6.6
通讯作者：
Csanyi, Gabor
中科院分区：
文献类型：
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作者：
Ghoshal, Pushpankur;Singla, Bhupesh;Csanyi, Gabor
目的：细胞外液及其溶质通过巨胞饮作用的内化需要肌动蛋白细胞骨架的动态重组、膜皱褶和细胞内称为巨胞饮体的大内吞空泡隔室的形成。虽然巨胞饮的煽动者，如生长因子和佛波醇酯，刺激NADPH氧化酶（Nox）的激活和Nox组装上游的信号转导介质，包括Rac 1和蛋白激酶C（PKC），参与巨胞饮，Nox酶在巨胞饮中的作用从未被调查。这项研究的目的是探讨Nox 2的作用和潜在的下游氧化还原信号参与macropinocytosis.Results：佛波酯肉豆蔻酸酯乙酸激活的人和小鼠巨噬细胞刺激膜皱褶，macropinosome形成，和随后的大分子摄取macropinocytosis。从机制上讲，我们发现，药理学阻断PKC，转录敲低Nox 2，清除细胞内的超氧阴离子废除佛波酯诱导的巨胞饮。我们观察到，通过抑制磷酸酶和张力蛋白同源物和激活磷酸肌醇-3-激酶（PI 3 K）/Akt途径的Nox 2衍生的活性氧导致肌动蛋白结合蛋白cofilin的激活，膜皱褶，和巨胞饮。类似地，巨噬细胞集落刺激因子对巨胞饮的激活涉及Nox 2介导的cofilin激活。此外，腹膜嵌合体实验表明，与野生型对照相比，高胆固醇血症ApoE（-/-）小鼠中的脂质巨胞饮摄取在Nox 2（y/-）巨噬细胞中减弱。创新与结论：总之，这些研究结果表明，一种新的Nox 2介导的机制，溶质摄取通过巨胞饮，具有广泛的影响，一般细胞生理和病理过程。这里描述的氧化还原机制也可以确定动脉粥样硬化和其他疾病的新目标，涉及巨胞饮。
Aims: Internalization of extracellular fluid and its solute by macropinocytosis requires dynamic reorganization of actin cytoskeleton, membrane ruffling, and formation of large endocytic vacuolar compartments, called macropinosomes, inside the cell. Although instigators of macropinocytosis, such as growth factors and phorbol esters, stimulate NADPH oxidase (Nox) activation and signal transduction mediators upstream of Nox assembly, including Rac1 and protein kinase C (PKC), are involved in macropinocytosis, the role of Nox enzymes in macropinocytosis has never been investigated. This study was designed to examine the role of Nox2 and the potential downstream redox signaling involved in macropinocytosis.Results: Phorbol myristate acetate activation of human and murine macrophages stimulated membrane ruffling, macropinosome formation, and subsequent uptake of macromolecules by macropinocytosis. Mechanistically, we found that pharmacological blockade of PKC, transcriptional knockdown of Nox2, and scavenging of intracellular superoxide anion abolished phorbol ester-induced macropinocytosis. We observed that Nox2-derived reactive oxygen species via inhibition of phosphatase and tensin homolog and activation of the phosphoinositide-3-kinase (PI3K)/Akt pathway lead to activation of actin-binding protein cofilin, membrane ruffling, and macropinocytosis. Similarly, activation of macropinocytosis by macrophage colony-stimulating factor involves Nox2-mediated cofilin activation. Furthermore, peritoneal chimera experiments indicate that macropinocytotic uptake of lipids in hypercholesterolemic ApoE(-/-) mice was attenuated in Nox2(y/-) macrophages compared with wild-type controls. Innovation andConclusion: In summary, these findings demonstrate a novel Nox2-mediated mechanism of solute uptake via macropinocytosis, with broad implications for both general cellular physiology and pathological processes. The redox mechanism described here may also identify new targets in atherosclerosis and other disease conditions involving macropinocytosis.