High expression of apolipoprotein E impairs lipid storage and promotes cell proliferation in human adipocytes

Abstract

Apolipoprotein E (apoE), a key regulator of lipid metabolism, is highly produced by adipose tissue and adipocytes. However, there is little information about its role on adipocyte functions. Because apoE-deficiency in adipocytes was shown to impair adipocyte differentiation, we investigated the consequences of apoE high expression on differentiation and proliferation of a human adipocytic cell line (SW872). SW872 cells were transfected with human apoE to induce a fivefold increase in apoE production and secretion. Adipocyte differentiation and proliferation were assayed by measuring lipid content, adipogenic gene expression, cell number, cell resistance to serum deprivation, and cell division kinetics. Cultured apoE-transfected cells accumulated less triglycerides and less cholesterol than control cells. This decrease in lipid accumulation was associated with a strong downregulation of peroxisome proliferator-activated receptors gamma1 and gamma2 and stearoyl-CoA desaturase 1. The decrease in lipid accumulation was not dependent on the presence of lipids, lipoproteins, or PPAR-gamma agonists in the culture medium, nor was it observed with exogenously added apoE. Moreover, we observed that apoE-transfected cells were more resistant to death induced by serum deprivation, and that these cells underwent more cell divisions than control cells. These results bring new evidence of apoE-involvement in metabolic disorders at the adipocyte level.

Defective triglyceride biosynthesis in CETP-deficient SW872 cells

“…The expression of both CETP and apoE is induced during adipocyte development ( 48,60 ). For both proteins, expression is closely linked to cellular TG and cholesterol content ( 50,60 ).…”

“…The expression of both CETP and apoE is induced during adipocyte development ( 48,60 ). For both proteins, expression is closely linked to cellular TG and cholesterol content ( 50,60 ). Blocking CETP expression reduces cellular TG levels ( 10 ), and adipocytes derived from apoE Ϫ / Ϫ mice have impaired capacity to accumulate TG ( 61,62 ).…”

The Endocrine Disruptor Mono-(2-Ethylhexyl) Phthalate Affects the Differentiation of Human Liposarcoma Cells (SW 872)

“…Since there is little information on SW 872 cell differentiation markers in literature, we investigated the gene expression of the well-known differentiation markers CCAAT/enhancer binding protein alpha (C/EBP-α), glucose transporter 4 (GLUT4), S100 calcium binding protein B (S100B) [32], [34], PPAR-α, PPAR-β/δ, PPAR-γ, TSPO, and PKCε, at specific times after differentiation.…”

“…SW 872 cells differentiate over time in culture without the use of any differentiation media [32]. Indeed, SW 872 are preadipocytes which stop proliferating when they reach 100% confluence.…”

Identification of Up-Regulated Low Molecular Weight Proteins in Human Adipocytes Treated with Glycoxidized Albumin~!2009-06-24~!2009-10-09~!2010-08-02~!

“…It is thus not surprising that many diabetic therapies target adipose tissue (thiazolidinedione, physical activity, etc) [5,6]. SW872 cells constitute a liposarcoma cell line often used as a human adipocyte cell model [7][8][9][10][11][12]. Nonetheless, proteomic analyses of SW872 cells have never been performed before.…”