Ligong Chen
Tsinghua University School of Medicine, China
Title: Role of organic cation transporter 3 (OCT3) in adipogenesis and novel OCT3 isoforms with internalized subcellular localization
Biography
Biography: Ligong Chen
Abstract
Organic cation transporter 3 (OCT3) mediates the uptake of the neurotransmitters epinephrine, norepinephrine and histamine and the neuromodulators agmatine, Cyclo (His-Pro) and salsolinol. It also plays a role in the therapeutic action of anti-diabetic drug metformin. Recent studies have identified OCT3 as a strong susceptibility gene for coronary artery disease (CAD) and prostate cancer. OCT3 exhibits a broader tissue distribution and is found relatively high-expressed in prostate，skeletal muscle，liver，adipose, yet the roles of OCT3 in adipose are largely unknown. Here，we used the pre-adipocyte 3T3-L1 to study the role of OCT3 in adipogenesis. We found that overexpression of mouse oct3 enhanced 3T3-L1 adipocyte differentiation, as evidenced by increased lipid accumulation by oil red o staining and elevated mRNA levels of both CCAAT/enhancer binding protein-α (C/EBPα), peroxisome proliferator-activated receptor-γ (PPARγ), and adipocyte fatty acid-binding protein (aP2). We also uncovered two novel isoforms of human SLC22A3 gene during cloning of OCT3 from human tissues and cell lines, which lack of exon 6 and exon 6，7 respectively. Transportation capacity of MPP＋ by those truncated OCT3 isoforms were significantly decreased compared with that of transfected full-length OCT3 HEK293 cells. GFP-tagged OCT3 novel isoforms revealed that truncated OCT3 retained in cytoplasm while full-length OCT3 is detected on cell plasma membrane.