Dan Cao, Jinjun Bian, Zi-Chun Hua, Lin Ma, Wei Chen, Xu Zhang, Ri Zhou, Shun Cheng, Wen-Zhu Sun, Qing-Cai Jiao, Wu Yin
The State Key Lab of Pharmaceutical Biotechnology, College of life Sciences Nanjing University, Nanjing, China.
Department of Anesthesiology and Intensive Care Unit, Changhai Hospital Affiliated Hospital of the Second Military Medical University, Shanghai, China.
EMBO Mol Med. 2015 Feb;7(2):140-57. doi: 10.15252/emmm.201404797.
Immunoparalysis is an important pathological mechanism in sepsis. However, an effective small molecule therapy is lacking. Here, we show that ouabain, a Na(+),K(+)-ATPase ligand, can reverse immunoparalysis in vitro, in vivo, and in clinical samples. Notably, the effect of ouabain was critically dependent on TNF-α expression. However, ouabain had opposing effects on the stability of TNF-α mRNA: Ouabain triggered miR-181 transcription, which promoted TNF-α mRNA degradation and induced immunoparalysis, and ouabain triggered the nuclear export of human antigen R (HuR), which stabilized TNF-α mRNA and suppressed immuno-paralysis. Interestingly, because the miR-181 binding site is located within the HuR binding site in the 3'-untranslated region of TNF-α, in ouabain-treated cells, HuR competed with miR-181 for binding to TNF-α mRNA and recruited TNF-α mRNA to stress granules, thereby stabilizing TNF-α mRNA and reversing immunoparalysis. Ouabain also induced GM-CSF and interferon-γ expression in a HuR-dependent manner. Hence, the fine-tuning of TNF-α mRNA stability by HuR and miR181 plays a crucial role in immunoparalysis, and Na(+),K(+)-ATPase ligands are promising agents for immunoparalysis therapy.
免疫麻痹是脓毒症的一种重要病理机制。然而，目前缺乏有效的小分子治疗方法。在此，我们表明哇巴因（一种Na⁺，K⁺-ATP酶配体）可在体外、体内及临床样本中逆转免疫麻痹。值得注意的是，哇巴因的作用严重依赖于TNF-α的表达。然而，哇巴因对TNF-α mRNA的稳定性有相反的影响：哇巴因触发miR-181转录，促进TNF-α mRNA降解并诱导免疫麻痹，而哇巴因触发人抗原R（HuR）的核输出，稳定TNF-α mRNA并抑制免疫麻痹。有趣的是，由于miR-181结合位点位于TNF-α 3'-非翻译区的HuR结合位点内，在哇巴因处理的细胞中，HuR与miR-181竞争结合TNF-α mRNA，并将TNF-α mRNA募集到应激颗粒中，从而稳定TNF-α mRNA并逆转免疫麻痹。哇巴因还以HuR依赖的方式诱导GM-CSF和干扰素-γ表达。因此，HuR和miR181对TNF-α mRNA稳定性的微调在免疫麻痹中起关键作用，并且Na⁺，K⁺-ATP酶配体是免疫麻痹治疗的有前景的药物。
