Department of Biochemistry, Middle East Technical University, Ankara, 06531, Turkey.
Analyst. 2010 Dec;135(12):3233-41. doi: 10.1039/c0an00540a. Epub 2010 Oct 29.
Statins are commonly used to control hypercholesterolemia and to prevent cardiovascular diseases. Among the statins, Simvastatin is one of the most frequently prescribed statins because of its efficacy in reducing LDL lipoprotein cholesterol levels, its tolerability, and its reduction of cardiovascular risk and mortality. Conflicting results have been reported with regard to benefits (pleiotropic effects) as well as risks (adverse effects) of simvastatin on different soft and hard tissues. In the current study, Attenuated Total Reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was used to obtain detailed information about protein conformational changes due to simvastatin therapy of soft tissues namely liver, testis, sciatic nerve and hard tissues such as femur and tibia. Protein secondary structural changes were predicted by intensity calculations from second derivative spectra and neural network (NN) analysis, using the amide I band (1700-1600 cm(-1)) of FTIR spectra. Moreover, based on protein secondary structural differences, hierarchical cluster analysis was carried out in the 1700-1600 cm(-1) region. The results of our study in liver, testis and sciatic nerve tissues revealed that simvastatin treatment significantly decreased alpha helix structure and beta sheet structure at 1638 cm(-1), while increased the anti-parallel and aggregated beta sheet and random coil structures implying a simvastatin-induced protein denaturation in treated groups. Different to soft tissues, the results of hard tissue studies on femur and tibia bones revealed increased alpha helix structure and decreased anti-parallel beta sheet, aggregated beta sheet and random coil structures implying more strengthened bone tissues in simvastatin-treated groups. Finally, the simvastatin-treated and control groups for all soft and bone tissues were successfully differentiated using cluster analysis. According to the heterogeneity values in the cluster analysis of these tissues, the sciatic nerve tissue was found to be the most affected tissue from simvastatin treatment among the studied soft tissues. In addition, the high heterogeneity value implied high secondary structural difference between control and simvastatin-treated groups in tibia bone tissues. These findings reveal that FTIR spectroscopy with bioinformatic analyses such as neural network and hierarchical clustering, allowed us to determine the simvastatin-induced protein conformational changes as adverse and pleiotropic effects of the drug on different soft and hard tissues.
他汀类药物通常用于控制高胆固醇血症和预防心血管疾病。在他汀类药物中，辛伐他汀因其降低 LDL 脂蛋白胆固醇水平的功效、耐受性以及降低心血管风险和死亡率而被广泛应用。然而，关于辛伐他汀对不同软组织和硬组织的益处（多效性效应）和风险（不良反应），已经有相互矛盾的结果报道。在本研究中，我们使用衰减全反射傅里叶变换红外（ATR-FTIR）光谱技术，获得了关于软组织（如肝脏、睾丸、坐骨神经）和硬组织（如股骨和胫骨）中由于辛伐他汀治疗导致的蛋白质构象变化的详细信息。我们通过从二阶导数光谱和神经网络（NN）分析中计算强度，使用 FTIR 光谱的酰胺 I 带（1700-1600 cm(-1))来预测蛋白质二级结构变化。此外，基于蛋白质二级结构的差异，我们在 1700-1600 cm(-1) 区域进行了层次聚类分析。我们在肝脏、睾丸和坐骨神经组织中的研究结果表明，辛伐他汀治疗显著降低了 1638 cm(-1)处的α螺旋结构和β片层结构，同时增加了反平行和聚集的β片层和无规卷曲结构，这表明治疗组中的蛋白质发生了辛伐他汀诱导的变性。与软组织不同，股骨和胫骨硬组织研究的结果表明，α螺旋结构增加，反平行β片层、聚集β片层和无规卷曲结构减少，这表明治疗组的骨骼组织得到了增强。最后，使用聚类分析成功区分了所有软组织和骨骼组织的辛伐他汀治疗组和对照组。根据这些组织聚类分析中的异质性值，发现与研究中的其他软组织相比，坐骨神经组织是受辛伐他汀治疗影响最大的组织。此外，胫骨骨组织中对照组和辛伐他汀治疗组之间的高异质性值意味着二级结构差异很大。这些发现表明，FTIR 光谱结合神经网络和层次聚类等生物信息学分析，可以确定辛伐他汀引起的蛋白质构象变化，即药物对不同软组织和硬组织的不良反应和多效性效应。
