Sex-specific pharmacological modulation of autophagic process in human umbilical artery smooth muscle cells

Sex has largely been neglected in cell studies. Therefore, we investigated the occurrence of sexual dimorphism in human umbilical artery smooth muscle cells (HUASMCs). In particular, we investigated the existence of sex differences in basal and in drug-induced autophagy, a process involved in cardiovascular diseases. HUASMCs were isolated from healthy and normal weight male and female newborns (MHUASMCs and FHUASMCs, respectively). Expression of the primary molecules involved in the autophagic process [beclin-1 and microtubule-associated protein 1 light chain 3 (LC3)], and PmTOR were detected using western blotting in basal conditions, after serum starvation, rapamycin and verapamil treatments. The level of constitutive autophagy, measured as the LC3II/I ratio, was similar in male and female HUASMCs in the basal condition. Serum starvation promoted autophagy in both cell types, but the increase was more pronounced in FHUASMCs, while 250nM rapamycin induced autophagy only in female cells. Moreover, the level of verapamil-induced autophagy was not different between the two sexes. Notably, in the basal condition, Beclin-1 was more elevated in MHUASMCs than in FHUASMCs, and the difference disappeared after serum starvation and exposure to rapamycin. After exposure to verapamil, the differences in Beclin-1 increased, with more elevated expression levels in female cells. PmTor did not differ in basal conditions, but it was significantly down-regulated by starvation only in FHUASMCs and by rapamycin both in male and female cells. Finally, a strong negative correlation was observed between the newborn's weight and basal autophagy in female cells and between the newborn's weight and the LC3II/I ratio in male verapamil-treated cells. These results indicate that sex-differences begin in utero, are parameter-specific and drug specific suggesting that HUASMCs are a suitable model for the screening of drugs and to study the influence of sex. The sex differences in the autophagy suggest sexually different pharmacodynamics effects of verapamil and rapamycin.