Kottom Theodore J, Hebrink Deanne M, Jenson Paige E, Nandakumar Vijayalakshmi, Wüthrich Marcel, Wang Huafeng, Klein Bruce, Yamasaki Sho, Lepenies Bernd, Limper Andrew H
Thoracic Diseases Research Unit, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905.
Department of Biochemistry, Mayo Clinic College of Medicine, Rochester, MN 55905.
J Immunol. 2017 May 1;198(9):3515-3525. doi: 10.4049/jimmunol.1600744. Epub 2017 Mar 15.
pneumonia (PCP) remains a major cause of morbidity and mortality within immunocompromised patients. In this study, we examined the potential role of macrophage-inducible C-type lectin (Mincle) for host defense against Binding assays implementing soluble Mincle carbohydrate recognition domain fusion proteins demonstrated binding to intact as well as to organism homogenates, and they purified major surface glycoprotein/glycoprotein A derived from the organism. Additional experiments showed that rats with PCP expressed increased Mincle mRNA levels. Mouse macrophages overexpressing Mincle displayed increased binding to life forms and enhanced protein tyrosine phosphorylation. The binding of to Mincle resulted in activation of FcRγ-mediated cell signaling. RNA silencing of Mincle in mouse macrophages resulted in decreased activation of Syk kinase after challenge, critical in downstream inflammatory signaling. Mincle-deficient CD4-depleted (Mincle) mice showed a significant defect in organism clearance from the lungs with higher organism burdens and altered lung cytokine responses during pneumonia. Interestingly, Mincle mice did not demonstrate worsened survival during PCP compared with wild-type mice, despite the markedly increased organism burdens. This may be related to increased expression of anti-inflammatory factors such as IL-1Ra during infection in the Mincle mice. Of note, the -infected Mincle mice demonstrated increased expression of known C-type lectin receptors Dectin-1, Dectin-2, and MCL compared with infected wild-type mice. Taken together, these data support a significant role for Mincle in modulating host defense during infection.
肺孢子菌肺炎（PCP）仍然是免疫功能低下患者发病和死亡的主要原因。在本研究中，我们研究了巨噬细胞诱导型C型凝集素（Mincle）在宿主抵御肺孢子菌感染中的潜在作用。使用可溶性Mincle碳水化合物识别域融合蛋白进行的结合试验表明，其可与完整的肺孢子菌以及菌体匀浆结合，并纯化了该菌的主要表面糖蛋白/糖蛋白A。进一步的实验表明，患有PCP的大鼠Mincle mRNA水平升高。过表达Mincle的小鼠巨噬细胞对肺孢子菌的结合增加，蛋白酪氨酸磷酸化增强。肺孢子菌与Mincle的结合导致FcRγ介导的细胞信号激活。在小鼠巨噬细胞中对Mincle进行RNA沉默导致肺孢子菌攻击后Syk激酶的激活减少，而Syk激酶在下游炎症信号传导中起关键作用。Mincle缺陷且CD4细胞耗竭的（Mincle）小鼠在肺孢子菌肺炎期间，肺部清除菌体的能力存在显著缺陷，菌体负荷更高，肺细胞因子反应改变。有趣的是，尽管Mincle小鼠的菌体负荷明显增加，但与野生型小鼠相比，其在PCP期间并未表现出更差的生存率。这可能与Mincle小鼠感染期间抗炎因子如IL-1Ra的表达增加有关。值得注意的是，与感染的野生型小鼠相比，感染肺孢子菌的Mincle小鼠中已知的C型凝集素受体Dectin-1、Dectin-2和MCL的表达增加。综上所述，这些数据支持Mincle在感染期间调节宿主防御中发挥重要作用。
