Gonthier Marie-Paule, Hoareau Laurence, Festy Franck, Matias Isabel, Valenti Marta, Bès-Houtmann Sandrine, Rouch Claude, Robert-Da Silva Christine, Chesne Serge, Lefebvre d'Hellencourt Christian, Césari Maya, Di Marzo Vincenzo, Roche Régis
Laboratoire de Biochimie et Génétique Moléculaire, Université de La Réunion, 15 avenue René Cassin-BP.7151, 97715 Saint-Denis, La Réunion, France.
Obesity (Silver Spring). 2007 Apr;15(4):837-45. doi: 10.1038/oby.2007.581.
Recently, an activation of the endocannabinoid system during obesity has been reported. More particularly, it has been demonstrated that hypothalamic levels of both endocannabinoids, 2-arachidonoylglycerol and anandamide (N-arachidonoylethanolamine), are up-regulated in genetically obese rodents. Circulating levels of both endocannabinoids were also shown to be higher in obese compared with lean women. Yet, the direct production of endocannabinoids by human adipocytes has never been demonstrated. Our aim was to evaluate the ability of human adipocytes to produce endocannabinoids.
The production of endocannabinoids by human adipocytes was investigated in a model of human white subcutaneous adipocytes in primary culture. The effects of leptin, adiponectin, and peroxisome proliferator-activated receptor (PPAR)-gamma activation on endocannabinoid production by adipocytes were explored. Endocannabinoid levels were determined by high-performance liquid chromatography (HPLC)-atmospheric pressure chemical ionization (APCI)-mass spectrometry (MS) analysis, leptin and adiponectin secretion measured by enzyme-linked immunosorbent assay (ELISA), and PPAR-gamma protein expression examined by Western blotting.
We show that 2-arachidonoylglycerol, anandamide, and both anandamide analogs, N-palmitoylethanolamine and N-oleylethanolamine, are produced by human white subcutaneous adipocytes in concentrations ranging from 0.042+/-0.004 to 0.531+/-0.048 pM/mg lipid extract. N-palmitoylethanolamine is the most abundant cannabimimetic compound produced by human adipocytes, and its levels are significantly down-regulated by leptin but not affected by adiponectin and PPAR-gamma agonist ciglitazone. N-palmitoylethanolamine itself does not affect either leptin or adiponectin secretion or PPAR-gamma protein expression in adipocytes.
This study has led to the identification of human adipocytes as a new source of endocannabinoids and related compounds. The biological significance of these adipocyte cannabimimetic compounds and their potential implication in obesity should deserve further investigations.
最近，有报道称肥胖期间内源性大麻素系统被激活。更具体地说，已经证明在遗传性肥胖啮齿动物中，下丘脑内两种内源性大麻素，即2-花生四烯酸甘油酯和花生四烯酸乙醇胺（N-花生四烯酰乙醇胺）的水平上调。与瘦女性相比，肥胖女性体内这两种内源性大麻素的循环水平也更高。然而，人类脂肪细胞直接产生内源性大麻素的情况从未得到证实。我们的目的是评估人类脂肪细胞产生内源性大麻素的能力。
在原代培养的人白色皮下脂肪细胞模型中研究人类脂肪细胞产生内源性大麻素的情况。探讨了瘦素、脂联素和过氧化物酶体增殖物激活受体（PPAR）-γ激活对脂肪细胞产生内源性大麻素的影响。通过高效液相色谱（HPLC）-大气压化学电离（APCI）-质谱（MS）分析测定内源性大麻素水平，通过酶联免疫吸附测定（ELISA）测量瘦素和脂联素分泌，并通过蛋白质印迹法检测PPAR-γ蛋白表达。
我们发现人白色皮下脂肪细胞能产生2-花生四烯酸甘油酯、花生四烯酸乙醇胺以及两种花生四烯酸乙醇胺类似物，即N-棕榈酰乙醇胺和N-油酰乙醇胺，其浓度范围为0.042±0.004至0.531±0.048 pM/毫克脂质提取物。N-棕榈酰乙醇胺是人类脂肪细胞产生的最丰富的类大麻化合物，其水平受瘦素显著下调，但不受脂联素和PPAR-γ激动剂吡格列酮影响。N-棕榈酰乙醇胺本身不影响脂肪细胞中瘦素或脂联素的分泌，也不影响PPAR-γ蛋白表达。
本研究已确定人类脂肪细胞是内源性大麻素及相关化合物的新来源。这些脂肪细胞类大麻化合物的生物学意义及其在肥胖中的潜在影响值得进一步研究。
