Effects of inorganic HgCl2 on adipogenesis.
Mercury is a common pollutant that alters glucose metabolism in adipocytes; however, the effect of HgCl2 on differentiating adipocytes and their subsequent metabolic function is not well understood. Two adipocyte models, the 3T3-L1 and C3H10T1/2 (10T1/2) cell lines, were differentiated in the presence of HgCl2. To assess the amount of differentiation in a population, markers of differentiation (i.e., PPARgamma and GLUT 4 expression and lipid accumulation) and functions of adipocytes (i.e., glucose transport and insulin-induced glucose transport) were measured. HgCl2 exposure significantly decreased the number of phenotypic adipocytes and PPARgamma expression in both 3T3-L1 and 10T1/2 cells without effects on cell viability. GLUT 4 was significantly reduced by HgCl2 treatment in 10T1/2 but not 3T3-L1 cells. Exposure to HgCl2 during differentiation increased basal glucose uptake in a dose-dependent manner (up to 2.5-fold) and decreased insulin-induced glucose uptake in 3T3-L1 adipocytes. In contrast, HgCl2 had little effect on basal or insulin-induced glucose uptake in 10T1/2 cells, possibly due to their lower insulin responsiveness. We examined the effect of HgCl2 exposure on signaling event involved in differentiation of adipocytes and cellular stress, namely, the phosphorylation of ERK1/2 and JNK, respectively. HgCl2 exposure had no effect on ERK1/2 phosphorylation in either cell line, increased JNK phosphorylation in the 10T1/2, and had no effect on JNK phosphorylation in 3T3-L1 cells. These data indicate HgCl2 exposure can inhibit the differentiation of fibroblasts into adipocytes as well as influence signaling events and the subsequent metabolic activity of differentiated adipocytes.
Barnes
David M
DM
Department of Animal Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA. barnes@calshp.cals.wisc.edu
Hanlon
Paul R
PR
Kircher
Emily A
EA
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D004785:Environmental Pollutants / Q000633:toxicity*; D005947:Glucose / Q000378:metabolism; D051275:Glucose Transporter Type 4; D007328:Insulin / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases; D050356:Lipid Metabolism; D048670:MAP Kinase Kinase 4; D008627:Mercuric Chloride / Q000633:toxicity*; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009124:Muscle Proteins; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
D004785:Environmental Pollutants; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D018160:Receptors, Cytoplasmic and Nuclear; C495693:Slc2a4 protein, mouse; D014157:Transcription Factors; D008627:Mercuric Chloride; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; D005947:Glucose