Involvement of Mesoderm-specific Transcript in Cell Growth of 3T3-L1 Preadipocytes

Abstract

Mesoderm-specific transcript (Mest) is an imprinted gene that is predominantly expressed in the embryonic and extraembryonic mesoderm, and its gene expression is the marker of the size of adipocytes. To characterize the expression effect of Mest gene products, we transfected mouse Mest into the 3T3-L1 cell line, which is a mouse preadipocyte cell line. The proliferation of the transfected 3T3-L1 cells was assessed via 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) colorimetry, and cell growth was assessed by counting the nuclei stained by Hoechst 33258. The 3T3-L1 cells transfected with recombinant Mest cDNA acquired the increased cell growth ability. Therefore, the gene products of Mest could be related to not only adipocyte expansion and adiposity but also mesoderm formation by enhancing the cell proliferation.Key words --mesoderm-specific transcript, preadipocyte, 3T3-L1, cell growth INTRODUTIONWhite adipose tissue is the organ that not only stores energy in the form of fat but also secretes endocrine hormones, adipokines, to maintain the homeostasis of an organism. 1, 2) Obesity is a growing and serious public health problem in developed countries. Obesity harms the homeostatic balance of adipose tissues; eventually, obesity can harm the whole body through the development of * To whom correspondence should be addressed: Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Yamashiro-cho, Tokushima 770-8514, Japan. Tel.: +81-88-602-8458; Fax: +81-88-655-3051; E-mail: ykadota@ph.bunriu.ac.jp type 2 diabetes mellitus, atherosclerosis, hypertension, and hyperlipidemia. 3,4) Adipocytes that ingest large quantities of lipids secrete adipokines, such as TNF-α and resistin, which cause insulin resistance. 5) Various factors such as sterol regulatory element-binding protein-1 (SREBP-1) and peroxisome proliferative activated receptor γ (PPARγ) enhance the proliferation, differentiation, and enlargement of adipocytes in obesity. 4,6)

Gene expression of mesoderm-specific transcript is upregulated as preadipocytes differentiate to adipocytes in vitro

“…Single and double asterisks indicate significant differences compared to controls at the P \ 0.05 and P \ 0.01 levels, respectively. Double hash symbols represents significance differences in gene expression levels in cells treated with 0.5 mM IBMX compared with untreated cells (P \ 0.01) vitro 3T3-L1 cultures, Mest gene overexpression facilitates preadipocyte proliferation and differentiation into adipocytes, and Mest siRNA suppresses adipogenic differentiation [8][9][10]. Because obesity results from fat mass expansion, which occurs through the proliferation, differentiation and hypertrophy of adipocytes, it is possible that Mest is important in the development of adipose tissue and fat mass.…”

“…Although Mest gene expression also regulates preadipocyte proliferation and adipocyte differentiation in 3T3-L1 cells [9,10], the mechanisms regulating expression of the Mest gene are not established in vitro. In this research, we analyzed Mest expression patterns during preadipocyteto-adipocyte differentiation in both 3T3-L1 and adiposederived stromal cells (ADCs) from C57BL/6J mice.…”

Mouse mesoderm-specific transcript inhibits adipogenic differentiation and induces trans-differentiation into hepatocyte-like cells in 3T3-L1 preadiocytes

“…We employed the pcDNA3.1 plasmid vector containing both the Mest and a neomycin resistance gene [ 12 ]. The 3T3-L1 cells (5 × 10 5 ) were seeded onto 60-mm dishes one day prior to transfection in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% Calf serum (CS) (Sigma-Aldrich, St. Louis, MO, USA).…”