Intermediate filaments and steroidogenesis in adrenal Y-1 cells: acrylamide stimulation of steroid production

Abstract

The possible role of intermediate filaments in steroidogenesis was investigated in Y-1 mouse adrenal tumor cells by treatment with acrylamide, which is thought to disrupt intermediate filaments without directly affecting microtubules or microfilaments. Treatment of cells with 5 mM acrylamide increases steroidogenesis after a lag period of 4-6 h and induces rounding of the cells at approximately the same time. The effect of acrylamide on steroidogenesis is not cAMP mediated and occurs before pregnenolone formation. DNA synthesis is inhibited, while protein synthesis is not. Acrylamide does not affect polymerization/depolymerization of microtubules in vitro. Acrylamide stimulation of steroidogenesis is additive with that produced by either colchicine or ACTH, implying that acrylamide, ACTH, and colchicine act at different rate-limiting steps in steroidogenesis. In addition, acrylamide stimulation is additive with that of forskolin. Pretreatment of cells with taxol, an agent that specifically promotes microtubule polymerization, decreases acrylamide-stimulated (as well as colchicine or ACTH-stimulated) steroidogenesis, implying that there must also be some shared elements in the stimulating pathways. We hypothesize that regulation of steroidogenesis in the Y-1 cell depends on 1) disruption of a vimentin or tubulin coat surrounding lipid droplets and 2) possible functional shortening of the distance between cholesterol droplets and the mitochondrion. However, because of interactions between cytoplasmic fibers, it is currently impossible to say whether interruption of any one of them is a direct or indirect stimulus of steroidogenesis.

Nestin expression in rat adrenal gland

“…Nevertheless, based on in vitro observations carried out on tumour cells, vimentin is usually considered as a normal constituent of the cytoskeleton of adrenocortical cells. This assumption has lead to extensive in vitro investigations on the involvement of vimentin in adrenal steroidogenesis (Almahbobi and Hall 1990;Almahbobi et al 1992;Sarria et al 1992;Shiver et al 1992) even though it is well known that, in addition to their cell-specific IFps, tissue cells adapted to cell culture conditions frequently express vimentin as well (Lazarides 1982;Traub and Shoeman 1994). This is also the case of bovine adrenomedullary cells that do not express vimentin in situ but that after only 9 h of culture do display strong vimentin immunoreactivity (Quintanar 2000).…”

Estrous cycle-dependent changes of Fas expression in the bovine corpus luteum: influence of keratin 8/18 intermediate filaments and cytokines

“…Initial treatments consisted of flasks and chamber slides treated with either culture medium (control) or 5mM acrylamide (Fisher Scientific, Pittsburgh, PA) for 4 h to disrupt K8/K18 filaments and potentially increase the cell surface expression of Fas. Acrylamide is a selective, reversible, disrupter of K8/K18 filaments in mammalian cells [27] that under short-term culture conditions does not adversely affect microtubules [28,29], organelles (e.g., mitochondria, [30]), steroid synthesis [31], or cell viability [11]. After the initial 4 h treatment period, all flasks and chamber slides were rinsed twice and the medium replaced.…”

Therapeutic Effect of Curcumin on Scanning Electron Microscopy of Rat Adrenal Gland in Experimental Fluorosis

“…These findings coincided with a study by Almahbobi [37] When ACTH stimulates the adrenal cells the steroid production is increased by using cholesterol reserve stored in lipid droplets. It has been investigated that intermediate filaments are involved in steroid hormone synthesis [38,39]; therefore, association between filaments and droplets might be involved in steroidogenesis. Kikuta et al [40] demonstrated the three dimensional organization of the collagen fibrillar network using an alkali water method and scanning electron microscopy.…”