Effect of Statins on Functional Expression of Membrane Transporters in L6 Rat Skeletal Muscle Cells

• Main Authors: Bakar, Nur Salwani, Kamali, Farhad, A. Brown, Colin D
• Format: Article
• Language: English
• Published: 2016
• Subjects: RA0421 Public health. Hygiene. Preventive Medicine
• Online Access: http://eprints.usm.my/35722/1/Bakar_2016.pdf; http://eprints.usm.my/35722/
• Institution: Universiti Sains Malaysia

Statins reduce LDL-cholesterol and the risk of atherosclerosis. They are generally safe, although statin-induced myopathy is relatively common. Membrane transporters play a crucial role in determining statin side effects. Little is known regarding the interaction of drug transporters in muscle cells with statins. Study aims: The present study aimed to determine the effect of statins on functional expression of monocarboxylate transporters (MCTs) and multidrug resistance-associated proteins (MRPs) in L6 rat skeletal myotube cells. Methods: Relative gene expression at mRNA level was confirmed by RT2 ProfilerTM Rat Drug Transporter PCR array. The uptake of 3H-labelled DL-lactate (1 μCi/ml) was measured to functionally expressed MCT function. The inhibition of [3H]-DL-lactate uptake was assessed in the presence or absence of statins and compared to that of the MCT inhibitors, phloretin and CHC. Transporter-mediated dye efflux was used as functional assay for the MRP efflux transporters. Results: In L6 rat skeletal myotubes, relatively high mRNA expression level was observed for Mct1and Mrp1for uptake and efflux transporters, respectively. The [3H]-DL-lactate uptake was shown to be a concentration-, pH-dependent and Na+-independent manner with Michaelis-Menten constant (Km) value of 16.17 ± 2.4 mM vs 15.63 ± 3.0 mM in the presence and absence of Na+, respectively. The maximum velocity of substrate binding (Vmax) of the DL-lactate uptake inhibition by lipophilic statins; simvastatin and atorvastatin, were in the same order as phloretin and CHC, while no significant inhibitory magnitude with hydrophilic statins; pravastatin and rosuvastatin. However, the L6 rat skeletal myotubes did not exhibit lactate efflux function. Among four of statins used, only simvastatin showed an affinity inhibition of MRP function in L6 cells. Conclusions: This study has shown that lipophilic statins significantly inhibit functional expression of MCTs, even though they have not shown relatively high inhibition impact on MRPs.