Expression of sterol carrier protein 2 (SCP2) in human adrenocortical tissue

Abstract

Sterol carrier protein 2 (SCP2) has been implicated in adrenal steroidogenesis by in vitro studies. In order to clarify the clinical significance of SCP2 in human steroidogenesis, we investigated the expression of SCP2 mRNA in various types of adrenocortical tissue and one testis and examined the correlation between the amounts of SCP2 and other values such as the free cholesterol content and the cholesterol side-chain cleavage (SCC) activity in the tissue mitochondria. The types of adrenocortical tissue examined included adrenocortical carcinomas (N = 3), adrenocortical adenomas from patients with Conn's syndrome (N = 3) and from patients with Cushing's syndrome (N = 3), non-functioning adrenocortical adenomas (N = 2) and normal adrenal glands (N = 2). Northern blot hybridization predominantly revealed a 1.8-kb SCP2 mRNA in all tissue specimens examined. The mRNA concentrations of SCP2 in two out of three adrenocortical carcinomas were relatively lower than those in other types of tissue. No other special tendency was observed regarding the mRNA expression levels in various tissue specimens. The mRNA concentrations of SCP2 correlated significantly with mitochondrial contents of free cholesterol (r = 0.67, p < 0.01), but was not correlated with the SCC activities in mitochondria measured by an in vitro enzyme assay. The mitochondrial SCC activities, however, were correlated significantly with the protein levels of mitochondrial P-450 scc determined by a Western blot analysis (r = 0.79, p < 0.01). The significant positive correlation between mRNA concentrations of SCP2 and the mitochondrial content of free cholesterol suggests that the central role of SCP2 in human steroidogenic tissues may be in part a translocation of cytoplasmic free cholesterol to the mitochondria, as demonstrated previously by in vitro studies.

Expression of fatty acyl‐CoA binding proteins in colon cells: response to butyrate and transformation

“…In addition, changes in the expression of SCP-2 have been reported in human adrenocortical tissue. A significant decrease in SCP-2 expression occurred in adrenocortical carcinomas when compared to normal tissue and benign neoplasms (42). Butyrate treatment did not affect SCP-2 expression in control or transformed cells.…”

Gene array analysis of the effects of chronic adrenocorticotropic hormone in vivo on immature rat adrenal glands

“…Sterol carrier protein-2 (Scp2) is a sterol transporter that binds cholesterol and is believed to be important in facilitating delivery of cholesterol to mitochondria in adrenal glands [41,42]. Chronic ACTH exposure had a small but significant effect on expression of this molecule, resulting in decreased expression as confirmed by real-time PCR.…”

Dynamic gene expressions of peripheral blood mononuclear cells in patients with acute exacerbation of chronic obstructive pulmonary disease: a preliminary study

“…In previous studies, these genes, including CEACAM1 , TFCP2L1 and SCP2 , were not found to be associated with COPD. The SCP2 gene is located within chromosome 1 and encodes the nonspecific lipid transfer protein SCP2 , which is involved in organellar fatty acid metabolism [ 27 , 28 ] and the translocation of cytoplasmic free cholesterol to the mitochondria [ 29 ]. Our results indicate that PBMCs from patients with stable COPD or AECOPD had downregulated SCP2 , which might point to severe metabolic disorder and thus that SCP2 downregulation might contribute to one of the common comorbidities of COPD [ 30 ].…”