Journal: Frontiers in Pharmacology

Article Title: TLR4 modulates simvastatin’s impact on HDL cholesterol and glycemic control

doi: 10.3389/fphar.2025.1655873

Figure Lengend Snippet: Simvastatin administration during fasting activates SREBP-2 and autophagy and augments FFA-induced APOA1 expression. (A) Huh7 cells cultured under serum-depleted conditions were treated with simvastatin (1, 5, or 10 μM) for 24 h. APOA1, PLTP, and GK mRNA levels were quantified by qPCR, normalized to the geometric mean of HPRT and B2M , and expressed as fold change relative to untreated controls. (B) Simvastatin (10 μM) enhances sodium oleate (50 μM)–induced APOA1 expression in serum-depleted Huh7 cells. Gene expression was measured by qPCR and normalized to HPRT and B2M . (C) Fasting-phase simvastatin treatment upregulates hepatic Srebf2 and its target genes in vivo . A/J mice received simvastatin by gavage for 5 weeks and were sacrificed 5 h after the final dose (ZT09); hepatic mRNA levels were normalized to Hprt . (D) Expression of autophagy-related genes ( Atg7 , Atg12 , Becn1 and others) in liver following fasting-phase simvastatin treatment. (E) Pharmacologic inhibition of autophagy attenuates simvastatin-induced APOA1 expression in Huh7 cells. Serum-starved cells were treated with simvastatin in the presence or absence of 500 µM leucine (mTORC1 activator) or 50 µM leupeptin (lysosomal protease inhibitor); APOA1 mRNA was measured by qPCR and normalized to HPRT1 and B2M . Data are mean ± SEM with individual data points overlaid (n indicated in each panel). Statistical significance: p < 0.05; * p < 0.01; ** p < 0.001 (two-way ANOVA with Tukey’s post hoc test).

Article Snippet: For fasting-mimetic conditions ( ; ), cells were washed twice with 1× PBS, incubated overnight in serum-free DMEM, and then treated for 24 h with 5 μM simvastatin alone or in combination with one or more of the following: 50 μM oleic acid (MilliporeSigma; C18:1, #O1383, purity >99% by GC); 10 μM GW6471 (MedChemExpress; #HY-15372, purity 99%), a selective PPARα antagonist; 500 μM leucine (MedChemExpress; #HY-N0486, purity 98%), which suppresses autophagy initiation via mTORC1 activation; or 50 μM leupeptin (MedChemExpress; #HY-18234A, purity 99.39%), a cysteine/serine/threonine protease inhibitor that blocks autophagic flux ( ; ; ).

Techniques: Expressing, Cell Culture, Gene Expression, In Vivo, Inhibition, Protease Inhibitor