Simvastatin profoundly impairs energy metabolism in primary human muscle cells

Objectives Simvastatin use is associated with muscular side effects, and increased risk for type 2 diabetes (T2D). In clinical use, simvastatin is administered in inactive lipophilic lactone-form, which is then converted to active acid-form in the body. Here, we have investigated if lactone- and acid-form simvastatin differentially affect glucose metabolism and mitochondrial respiration in primary human skeletal muscle cells. Methods Muscle cells were exposed separately to lactone- and acid-form simvastatin for 48 h. After pre-exposure, glucose uptake and glycogen synthesis were measured using radioactive tracers; insulin signalling was detected with Western blotting; and glycolysis, mitochondrial oxygen consumption and ATP production were measured with Seahorse XFe96 analyzer. Results Lactone-form simvastatin increased glucose uptake and glycogen synthesis, whereas acid-form simvastatin did not affect glucose uptake and decreased glycogen synthesis. Phosphorylation of insulin signalling targets Akt substrate 160 kDa (AS160) and glycogen synthase kinase 3β (GSK3β) was upregulated with lactone-, but not with acid-form simvastatin. Exposure to both forms of simvastatin led to a decrease in glycolysis and glycolytic capacity, as well as to a decrease in mitochondrial respiration and ATP production. Conclusions These data suggest that lactone- and acid-forms of simvastatin exhibit differential effects on non-oxidative glucose metabolism as lactone-form increases and acid-form impairs glucose storage into glycogen, suggesting impaired insulin sensitivity in response to acid-form simvastatin. Both forms profoundly impair oxidative glucose metabolism and energy production in human skeletal muscle cells. These effects may contribute to muscular side effects and risk for T2D observed with simvastatin use.

SUN-657 The Effect of Simvastatin on Glucose Metabolism in Primary Human Muscle Cells

Statin use, especially treatment with simvastatin, is associated with impaired insulin secretion and whole-body insulin sensitivity, and increased risk for T2D. Here, we investigated the direct effects of lactone- and acid-forms of simvastatin on glucose metabolism in primary human skeletal muscle cells. Exposure of human myotubes to lactone-form simvastatin for 48 h increased glucose uptake and glucose incorporation into glycogen, whereas the acid-form did not affect glucose uptake and decreased glucose incorporation into glycogen. These metabolic actions were accompanied by changes in insulin signaling, as phosphorylation of AS160 and GSK3β was upregulated with lactone-, but not with acid-form simvastatin. Exposure to both lactone and acid-forms of simvastatin led to a decrease in glycolysis and glycolytic capacity, as well as to a decrease in mitochondrial respiration and ATP production. Collectively these data indicate that lactone- and acid forms of simvastatin exhibit differences such that lactone-form increases, and acid-form impairs glucose incorporation into glycogen. Exposure to either form of simvastatin, however, impairs glycolysis and mitochondrial oxidative metabolism in human skeletal muscle cells.

Oligomeric silsesquioxanes containing dye Rhodamine B in an organic shell

A method for the synthesis of amphiphilic reactive oligomeric silsesquioxanes (OSS) with fragments of Rhodamine B fluorescent dye and hydroxyl groups in organic shell (OSS-Rh) by the reaction between carboxyl groups of the dye and epoxy groups of the mixture of oligomeric silsesquioxanes (OSS-Ep) was developed. The structure of the synthesized substance was characterized by the methods of IR and 1H NMR spectroscopy. The UV-spectrum of the OSS-Rh compound in dimethylformamide (DMF) solution was characterized by absorption bands of both the colored zwitterion (562 nm and 350 nm) and the colorless lactone (318 nm) forms of Rhodamine B. The absorption band at 562 nm in the spectrum of OSS-Rh in DMF solution was more intense than the analogous band in the spectrum of the original Rhodamine B. Therefore, the attachment of Rhodamine B to the silsesquioxane core of an oligomeric silsesquioxanes mixture does not have a significant effect on the position of the absorption maxima in UV-spectrum and prevents dye’s fragments from converting to the colorless lactone form. In the fluorescence spectra of both Rhodamine B and OSS-Rh, obtained using ethyl alcohol as a solvent, a peak is observed at λmax = 570 nm (λex = 500 nm). In the fluorescence spectrum of OSS-Rh obtained in DMF, a fluorescence peak is observed at λmax = 586 nm (λex = 520 nm). Consequently, the replacement of ethanol by DMF is accompanied by a bathochromic shift of the fluorescence peak of OSS-Rh. In the fluorescence spectrum of Rhodamine B at the same conditions, the peak of fluorescence is absent because of transition of the dye to the lactone form. The compounds obtained can be used in formation of functional Langmuir-Blodgett films as well as in obtaining polymer nanocomposites by covalent bonding.

Lovastatin lactone may improve irritable bowel syndrome with constipation (IBS-C) by inhibiting enzymes in the archaeal methanogenesis pathway

Methane produced by the methanoarchaeonMethanobrevibacter smithii(M. smithii) has been linked to constipation, irritable bowel syndrome with constipation (IBS-C), and obesity. Lovastatin, which demonstrates a cholesterol-lowering effect by the inhibition of HMG-CoA reductase, may also have an anti-methanogenesis effect through direct inhibition of enzymes in the archaeal methanogenesis pathway. We conducted protein-ligand docking experiments to evaluate this possibility. Results are consistent with recent clinical findings.METHODS: F420-dependent methylenetetrahydromethanopterin dehydrogenase (mtd), a key methanogenesis enzyme was modeled for two different methanogenic archaea:M. smithiiandMethanopyrus kandleri. Once protein models were developed, ligand-binding sites were identified. Multiple ligands and their respective protonation, isomeric and tautomeric representations were docked into each site, including F420-coenzyme (natural ligand), lactone and β-hydroxyacid forms of lovastatin and simvastatin, and other co-complexed ligands found in related crystal structures.RESULTS: 1) Generally, for each modeled site the lactone form of the statins had more favorable site interactions compared to F420; 2) The statin lactone forms generally had the most favorable docking scores, even relative to the native template PDB ligands; and 3) The statin β-hydroxyacid forms had less favorable docking scores, typically scoring in the middle with some of the F420 tautomeric forms. Consistent with these computational results were those from a recent phase II clinical trial (NCT02495623) with a proprietary, modified-release lovastatin-lactone (SYN-010) in patients with IBS-C, which showed a reduction in symptoms and breath methane levels, compared to placebo.CONCLUSION: The lactone form of lovastatin exhibits preferential binding over the native-F420 coenzyme ligandin silicoand thus could inhibit the activity of the keyM. smithiimethanogenesis enzymemtdin vivo. Statin lactones may thus exert a methane-reducing effect that is distinct from cholesterol lowering activity, which requires HMGR inhibition by statin β-hydroxyacid forms.

Lovastatin lactone may improve irritable bowel syndrome with constipation (IBS-C) by inhibiting enzymes in the archaeal methanogenesis pathway

Methane produced by the methanoarchaeonMethanobrevibacter smithii(M. smithii) has been linked to constipation, irritable bowel syndrome with constipation (IBS-C), and obesity. Lovastatin, which demonstrates a cholesterol-lowering effect by the inhibition of HMG-CoA reductase, may also have an anti-methanogenesis effect through direct inhibition of enzymes in the archaeal methanogenesis pathway. We conducted protein-ligand docking experiments to evaluate this possibility. Results are consistent with recent clinical findings.METHODS: F420-dependent methylenetetrahydromethanopterin dehydrogenase (mtd), a key methanogenesis enzyme was modeled for two different methanogenic archaea:M. smithiiandMethanopyrus kandleri. Once protein models were developed, ligand-binding sites were identified. Multiple ligands and their respective protonation, isomeric and tautomeric representations were docked into each site, including F420-coenzyme (natural ligand), lactone and β-hydroxyacid forms of lovastatin and simvastatin, and other co-complexed ligands found in related crystal structures.RESULTS: 1) Generally, for each modeled site the lactone form of the statins had more favorable site interactions compared to F420; 2) The statin lactone forms generally had the most favorable docking scores, even relative to the native template PDB ligands; and 3) The statin β-hydroxyacid forms had less favorable docking scores, typically scoring in the middle with some of the F420 tautomeric forms. Consistent with these computational results were those from a recent phase II clinical trial (NCT02495623) with a proprietary, modified-release lovastatin-lactone (SYN-010) in patients with IBS-C, which showed a reduction in symptoms and breath methane levels, compared to placebo.CONCLUSION: The lactone form of lovastatin exhibits preferential binding over the native-F420 coenzyme ligandin silicoand thus could inhibit the activity of the keyM. smithiimethanogenesis enzymemtdin vivo. Statin lactones may thus exert a methane-reducing effect that is distinct from cholesterol lowering activity, which requires HMGR inhibition by statin β-hydroxyacid forms.

Lovastatin lactone may improve irritable bowel syndrome with constipation (IBS-C) by inhibiting enzymes in the archaeal methanogenesis pathway

Methane produced by the methanoarchaeonMethanobrevibacter smithii(M. smithii) has been linked to constipation, irritable bowel syndrome with constipation (IBS-C), and obesity. Lovastatin, which demonstrates a cholesterol-lowering effect by the inhibition of HMG-CoA reductase, may also have an anti-methanogenesis effect through direct inhibition of enzymes in the archaeal methanogenesis pathway. We conducted protein-ligand docking experiments to evaluate this possibility. Results are consistent with recent clinical findings.METHODS: F420-dependent methylenetetrahydromethanopterin dehydrogenase (mtd), a key methanogenesis enzyme with a known sequence but no tertiary protein structural information, was modeled for two different methanogenic archaea:M. smithiiandMethanopyrus kandleri. Once protein models were developed, ligand-binding sites were identified. Multiple ligands and their respective protonation, isomeric and tautomeric representations were docked into each site, including F420-coenzyme (natural ligand), lactone and β-hydroxyacid forms of lovastatin and simvastatin, and other co-complexed ligands found in related crystal structures.RESULTS: 1) Generally, for each modeled site the lactone form of the statins had more favorable site interactions compared to F420; 2) The statin lactone forms generally had the most favorable docking scores, even relative to the native template PDB ligands; and 3) The statin β-hydroxyacid forms had less favorable docking scores, typically scoring in the middle with some of the F420 tautomeric forms. Consistent with these computational results were those from a recent phase II clinical trial (NCT02495623) with a proprietary, modified-release lovastatin-lactone (SYN-010) in patients with IBS-C, which showed a reduction in symptoms and breath methane levels, compared to placebo.CONCLUSION: The lactone form of lovastatin exhibits preferential binding over the native-F420 coenzyme ligandin silicoand thus could inhibit the activity of the keyM. smithiimethanogenesis enzymemtdin vivo. Statin lactones may thus exert a methane-reducing effect that is distinct from cholesterol lowering activity, which requires HMGR inhibition by statin β-hydroxyacid forms.

Self-assembly of the active lactone form of a camptothecin–phospholipid complex for sustained nuclear drug delivery

(A) Illustration of the preparation of the CPT–SPC complex and its self-assembled nanoparticles (CPT–SPC NPs). (B) Illustration of drug delivery of the self-assembled CPT–SPC NPs.