Evaluation and discrimination of simvastatin-induced structural alterations in proteins of different rat tissues by FTIR spectroscopy and neural network analysis

Abstract

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.

The Effects of Short-Term Chronic Ethanol Intoxication and Ethanol Withdrawal on the Molecular Composition of the Rat Hippocampus by FT-IR Spectroscopy

“…Protein secondary structure was predicted using NNs based on amide I band between 1700 and 1600 cm −1 . In recent years, this method has been effectively applied to determine protein secondary structure in biological systems (Akkas et al., 2007; Bozkurt et al., 2010; Garip et al., 2010). Amide I band was preprocessed before applying to the NNs.…”

“…A recent study (Petibois et al., 2006) showed that there is no significant difference in the analytical performance between FT‐IR and other analytical techniques including biochemical measurements, which require an extensive use of chemical reagents. Its application was reported on the evaluation of the changes in macromolecules such as proteins, both qualitatively and quantitatively (Akkas et al., 2007; Cakmak et al., 2003; Garip et al., 2010; Surewicz et al., 1993). The use of FT‐IR as a novel method was proposed to monitor lipid peroxidation to support biochemical tests (Severcan et al., 2005b).…”

Interferência Das Estatinas Em Exames Laboratoriais

“…Quando um paciente necessita de estatina para a prevenção ou tratamento da doença coronariana, o mé-dico deve prescrever tal medicamento, mesmo que haja doença hepática crônica ou história pregressa de hepatopatia aguda (38). No entanto, quando os níveis de tran-saminases estão acima de três vezes o limite superior da normalidade antes do início do tratamento, deve maior prudência, sugerindo a investigação da causa da doença hepática antes de prescrever uma estatina.…”

“…As sinvastatinas, por sua vez, são estatinas hábeis em aumentar a atividade da fosfatase alcalina, nível de expressão da osteocalcina e deposição de minerais em células humanas, que seria um efeito benéfico (38). Algumas pesquisas mostraram que estes medicamentos podem estimular a formação óssea, verificada devido ao aumento da atividade da fosfatase alcalina, um efeito anabólico sobre o tecido ósseo pelo aumento da diferenciação dos osteoblastos (40,41).…”

Structural characterization of recombinant bovine Goαby spectroscopy and homology modeling

“…For example, neural networks based on Amide I band located between 1700 and 1660 cm −1 in infrared spectroscopy offers new computational approach that has served as a reliable alternative method for predicting protein secondary structure in recent years [19,20,40,41]. This approach has been also successfully applied to proteins of biological tissues and membranes [1,2,12].…”