Effects of nitric oxide on proliferation and differentiation of rat brown adipocytes in primary cultures

• Published in: British journal of pharmacology 1998-10, Vol.125 (4), p.888-894
• Main Authors: Nisoli, Enzo, Clementi, Emilio, Tonello, Cristina, Sciorati, Clara, Briscini, Luca, Carruba, Michele O
• Format: Article
• Language: English
• Subjects: Adipose Tissue, Brown - drug effects; Animals; Base Sequence; Biological and medical sciences; Brown adipocytes; cell differentiation; Cell Differentiation - drug effects; Cell Division - drug effects; cell proliferation; Cells, Cultured; Cyclic GMP - analogs & derivatives; Cyclic GMP - pharmacology; energy expenditure; Fundamental and applied biological sciences. Psychology; Glutathione - analogs & derivatives; Glutathione - pharmacology; Male; Molecular Sequence Data; NG-Nitroarginine Methyl Ester - pharmacology; nitric oxide; Nitric Oxide - pharmacology; Nitric Oxide Synthase - antagonists & inhibitors; Nitroso Compounds - pharmacology; obesity; Penicillamine - analogs & derivatives; Penicillamine - pharmacology; peroxisome proliferator‐activated receptor‐γ; Radioimmunoprecipitation Assay; Rats; Rats, Sprague-Dawley; S-Nitrosoglutathione; Time Factors; uncoupling protein‐1; Vertebrates: skin, associated glands, phaneres, light organs, various exocrine glands (salt gland, uropygial gland...), adipose tissue, connective tissue
• ISSN: 0007-1188; 1476-5381
• DOI: 10.1038/sj.bjp.0702131

1 In the present work, we study the effect of NO on the proliferation and differentiation of brown fat cells in primary cultures. 2 Brown fat precursor cells isolated from rat brown adipose tissue were cultured for 8 days until confluence and treated daily with the NO donating agents, S‐nitroso‐acetyl penicillamine (SNAP) or S‐nitroso‐L‐glutathione (GSNO). Both agents (300 μM) decreased cell proliferation approximately 8 fold on day 8. The inhibitory effect of NO was unlikely to be due to cytotoxicity since (i) cells never completely lost their proliferation capacity even after 8 days of exposure to repeated additions of SNAP or GSNO, and (ii) the inhibitory effect was reversible after removal of the media containing NO donors. 3 Daily treatment with nitric oxide synthase inhibitors, such as NG‐nitro‐L‐arginine methyl ester (L‐NAME, 300 μM), led to the stimulation of cell proliferation by 44±5%, n=3, suggesting that NO, endogenously produced in brown adipocytes, may be involved in modulating cell growth. 4 Daily treatment with both SNAP or GSNO induced significant mitochondriogenesis, measured as the mitochondrial conversion of 3‐[4,5‐dimethylthiazol‐2‐yl‐]‐2,5‐diphenyl tetrazolium bromide (MTT) to formazan, whilst daily treatment with L‐NAME was without effect. 5 The inhibition of cell proliferation by NO donors was accompanied by the expression of two genes coding for peroxisome proliferator activated receptor‐γ and uncoupling protein‐1, which are upregulated during differentiation. 6 Increasing cyclic GMP in cells by 8‐bromo‐cyclic GMP (100–1000 μM) did not reproduce the observed NO effects on either cell number or gene expression. On the other hand, chronic treatment with the inhibitor of the NO‐stimulated guanylyl cyclase, 1H‐[1,2,4]oxadiazole[4,3‐a]quinoxalin‐1‐one (ODQ), reduced the expression of peroxisome proliferator activated receptor‐γ and uncoupling protein‐1. British Journal of Pharmacology (1998) 125, 888–894; doi:10.1038/sj.bjp.0702131