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-Synuclein Is an Adipocyte-Neuron Gene Coordinately Expressed with Leptin and Increased in Human Obesity1–3,
4 USDA/Agricultural Research Service Western Human Nutrition Research Center, Davis, CA 95616; 5 Institute National de la Santé et de la Recherche Médicale U626, Marseille and Faculté de Médecine, Université de la Méditerranée, 13385 Marseille Cedex, France; 6 Assistance Publique/Hopitaux de Paris, Pitié-Saltéprière and Tenon Hospitals, 75013 Paris, France 7 University Pierre and Marie Curie, 75006 Paris, France; 8 Institute National de la Santé et de la Recherche Médicale U872, Cordelier Research Center, 75006 Paris, France; 9 School of Biosciences, Cardiff University, Cardiff CF10 3US UK; 10 Carl T. Hayden Veterans Affairs Medical Center, Phoenix, AZ 85012; 11 Campbell Family Institute for Breast Cancer Research, Toronto M5G 1L7 Canada; and 12 Department of Nutrition, University of California, Davis, CA 95616
* To whom correspondence should be addressed. E-mail: sean.h.adams{at}ars.usda.gov.
Recently, we characterized tumor suppressor candidate 5 (Tusc5) as an adipocyte-neuron PPAR
target gene. Our objective herein was to identify additional genes that display distinctly high expression in fat and neurons, because such a pattern could signal previously uncharacterized functional pathways shared in these disparate tissues.
-Synuclein, a marker of peripheral and select central nervous system neurons, was strongly expressed in white adipose tissue (WAT) and peripheral nervous system ganglia using bioinformatics and quantitative PCR approaches.
-Synuclein expression was determined during adipogenesis and in subcutaneous (SC) and visceral adipose tissue (VAT) from obese and nonobese humans.
-Synuclein mRNA increased from trace levels in preadipocytes to high levels in mature 3T3-L1 adipocytes and decreased
50% following treatment with the PPAR
agonist GW1929 (P < 0.01). Because
-synuclein limits growth arrest and is implicated in cancer progression in nonadipocytes, we suspected that expression would be increased in situations where WAT plasticity/adipocyte turnover are engaged. Consistent with this postulate, human WAT
-synuclein mRNA levels consistently increased in obesity and were higher in SC than in VAT; i.e. they increased
1.7-fold in obese Pima Indian adipocytes (P = 0.003) and
2-fold in SC and VAT of other obese cohorts relative to nonobese subjects. Expression correlated with leptin transcript levels in human SC and VAT (r = 0.887; P < 0.0001; n = 44).
-Synuclein protein was observed in rodent and human WAT but not in negative control liver. These results are consistent with the hypothesis that
-synuclein plays an important role in adipocyte physiology.