Rezzani Rita, Pompili Elena, Agostini Cristina, Buffoli Barbara, Bonomini Francesca, Nori Stefania, Fumagalli Lorenzo, Bianchi Rossella
Division of Human Anatomy, Department of Biomedical Sciences and Biotechnologies, University of Brescia, V.le Europa 11, 25123, Brescia, Italy.
Int Immunopharmacol. 2006 Jun;6(6):962-7. doi: 10.1016/j.intimp.2006.01.014. Epub 2006 Feb 17.
Myosins constitute a large family of molecular motors, hydrolyzing ATP and producing cellular movement. To date, a large number of novel isoforms have been found in muscle and non-muscle cells. Among non-muscle myosins, non-muscle myosin heavy chain (NMHC) II-A and II-B have been well characterized. An additional member of NMHC II-B, with a molecular weight of 220 kDa, was recently identified in bovine skeletal muscle. NMHC II-B proteins, in particular, have been suggested to be a useful early molecular marker for the detection of pathological conditions during acute or chronic organ rejection in which fibrotic changes occur. Since it is known that treatment with cyclosporine A (CsA), an immunosuppressive drug successfully used for preventing organ rejection and autoimmune diseases, is often associated with several side effects (hypertension and nephrotoxicity), the aims of this study were: (1) to demonstrate the homology of the new NMHC protein (220 kDa) in other mammalian species, such as Wistar rats; (2) to evaluate, by morphological and immunohistochemical studies, the possible changes induced by CsA treatment in NMHC protein (220 kDa) cellular localization and/or in its expression levels in myocardial tissue. First of all, our results showed a greater homology of the new NMHC within the same isoforms across species and between isoforms in the same specie; moreover, we observed that this protein increased following CsA treatment. This could be explained as a tentative of cardiac tissue to maintain the structural integrity of intercalated disks and so the contraction/relaxation process.
肌球蛋白构成了一个分子马达大家族，能水解三磷酸腺苷（ATP）并产生细胞运动。迄今为止，在肌肉和非肌肉细胞中已发现大量新的亚型。在非肌肉肌球蛋白中，非肌肉肌球蛋白重链（NMHC）II - A和II - B已得到充分表征。最近在牛骨骼肌中鉴定出了NMHC II - B的另一个成员，其分子量为220 kDa。特别是NMHC II - B蛋白，已被认为是检测急性或慢性器官排斥过程中发生纤维化变化的病理状况的一种有用的早期分子标志物。由于已知成功用于预防器官排斥和自身免疫性疾病的免疫抑制药物环孢素A（CsA）的治疗常常伴有多种副作用（高血压和肾毒性），本研究的目的是：（1）证明新的NMHC蛋白（220 kDa）在其他哺乳动物物种（如Wistar大鼠）中的同源性；（2）通过形态学和免疫组织化学研究，评估CsA治疗对心肌组织中NMHC蛋白（220 kDa）的细胞定位和/或其表达水平可能产生的变化。首先，我们的结果表明，新的NMHC在不同物种的同亚型之间以及同一物种的不同亚型之间具有更高的同源性；此外，我们观察到该蛋白在CsA治疗后增加。这可以解释为心脏组织试图维持闰盘的结构完整性，从而维持收缩/舒张过程。
