The inhibition of microtubule dynamics instability alters lipid homeostasis in TM4 Sertoli cells

Abstract

Sertoli cells (SC) structurally support and transport nutrients to germ cells during spermatogenesis facilitated by an active cytoskeleton. Chemical perturbation of SC microtubule (MT) dynamics instability leads to premature germ cell exfoliation demonstrating that this process is essential for male fertility, yet the effects of MT damaging drugs on SC lipid metabolism have been less explored. The aim of this study was to advance our understanding of how adequate SC MT dynamicity is needed to finely tune lipid homeostasis. To elucidate the role of MT dynamics instability on the latter, we suppressed MT dynamicity by long-term exposures to 10 nM of nocodazole (NCZ) on TM4-SC cultures. Inhibition of MT dynamics instability affected the distribution of [3H] arachidonate on TM4-SC. Triacylglycerols (TAG) exhibited a higher proportion of the [3H] label, with significantly lower percentages in the mitochondrial phospholipid cardiolipin, and notably, also in phosphatidylethanolamine. A noteworthy and progressive accumulation of lipid droplets during the period of exposure to NCZ was accompanied by increased TAG levels but not cholesterol levels in TM4-SC. NCZ-exposed cells reduced their mitochondrial membrane potential and increased ROS production without triggering apoptosis, had a compromised autophagic flux, and lost their transferrin expression. Although SC morphology was preserved, the NCZ-exposed cells displayed alteration of the normal organization of microfilaments (f-actin) and intermediate filaments (vimentin). Our findings suggest that a preserved MT dynamicity is essential in the maintenance of lipid and fatty acids homeostasis in SC, and thus highlights a novel target in these cells for drugs that impair MT dynamicity.