Department of Surgery, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts, United States of America ; Athinoula A. Martinos Center of Biomedical Imaging, Massachusetts General Hospital, Boston, Massachusetts, United States of America ; Shriners Hospitals for Children Boston, Boston, Massachusetts, United States of America.
PLoS One. 2013 Sep 30;8(9):e74528. doi: 10.1371/journal.pone.0074528. eCollection 2013.
Mitochondria integrate distinct signals that reflect specific threats to the host, including infection, tissue damage, and metabolic dysfunction; and play a key role in insulin resistance. We have found that the Pseudomonas aeruginosa quorum sensing infochemical, 2-amino acetophenone (2-AA), produced during acute and chronic infection in human tissues, including in the lungs of cystic fibrosis (CF) patients, acts as an interkingdom immunomodulatory signal that facilitates pathogen persistence, and host tolerance to infection. Transcriptome results have led to the hypothesis that 2-AA causes further harm to the host by triggering mitochondrial dysfunction in skeletal muscle. As normal skeletal muscle function is essential to survival, and is compromised in many chronic illnesses, including infections and CF-associated muscle wasting, we here determine the global effects of 2-AA on skeletal muscle using high-resolution magic-angle-spinning (HRMAS), proton ((1)H) nuclear magnetic resonance (NMR) metabolomics, in vivo (31)P NMR, whole-genome expression analysis and functional studies. Our results show that 2-AA when injected into mice, induced a biological signature of insulin resistance as determined by (1)H NMR analysis-, and dramatically altered insulin signaling, glucose transport, and mitochondrial function. Genes including Glut4, IRS1, PPAR-γ, PGC1 and Sirt1 were downregulated, whereas uncoupling protein UCP3 was up-regulated, in accordance with mitochondrial dysfunction. Although 2-AA did not alter high-energy phosphates or pH by in vivo (31)P NMR analysis, it significantly reduced the rate of ATP synthesis. This affect was corroborated by results demonstrating down-regulation of the expression of genes involved in energy production and muscle function, and was further validated by muscle function studies. Together, these results further demonstrate that 2-AA, acts as a mediator of interkingdom modulation, and likely effects insulin resistance associated with a molecular signature of mitochondrial dysfunction in skeletal muscle. Reduced energy production and mitochondrial dysfunctional may further favor infection, and be an important step in the establishment of chronic and persistent infections.
线粒体整合了反映宿主特定威胁的不同信号，包括感染、组织损伤和代谢功能障碍；并在胰岛素抵抗中发挥关键作用。我们发现，铜绿假单胞菌群体感应信息素 2-氨基苯乙酮（2-AA），在人体组织（包括囊性纤维化（CF）患者的肺部）的急性和慢性感染期间产生，作为一种跨物种免疫调节信号，促进病原体的持续存在，并使宿主对感染产生耐受性。转录组研究结果表明，2-AA 通过触发骨骼肌线粒体功能障碍对宿主造成进一步伤害。由于正常的骨骼肌功能对生存至关重要，并且在许多慢性疾病中受到损害，包括感染和 CF 相关的肌肉消耗，因此我们在这里使用高分辨率魔角旋转（HRMAS）、质子（1H）核磁共振（NMR）代谢组学、体内（31）P NMR、全基因组表达分析和功能研究来确定 2-AA 对骨骼肌的全局影响。我们的结果表明，当 2-AA 注射到小鼠体内时，通过 1H NMR 分析确定其诱导了胰岛素抵抗的生物学特征，并显著改变了胰岛素信号、葡萄糖转运和线粒体功能。包括 Glut4、IRS1、PPAR-γ、PGC1 和 Sirt1 在内的基因下调，而解偶联蛋白 UCP3 上调，与线粒体功能障碍一致。尽管体内（31）P NMR 分析表明 2-AA 没有改变高能磷酸化合物或 pH，但它显著降低了 ATP 合成的速率。这一影响得到了涉及能量产生和肌肉功能的基因表达下调的结果的证实，并通过肌肉功能研究进一步验证。总之，这些结果进一步表明，2-AA 作为跨物种调节的介质，可能会影响与骨骼肌线粒体功能障碍相关的分子特征的胰岛素抵抗。能量产生减少和线粒体功能障碍可能进一步有利于感染，并成为慢性和持续性感染建立的重要步骤。
