Adipose triglyceride lipase protein abundance and translocation to the lipid droplet increase during leptin-induced lipolysis in bovine adipocytes
| Autor: | D. A. Koltes, D.M. Spurlock, M.E. Spurlock |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Leptin
STAT3 Transcription Factor 0301 basic medicine medicine.medical_specialty Lipolysis Hormone-sensitive lipase Energy homeostasis 03 medical and health sciences 0302 clinical medicine Endocrinology Food Animals Internal medicine Lipid droplet Adipocytes medicine Animals Phosphorylation Lipase biology Chemistry digestive oral and skin physiology Isoproterenol Lipid metabolism Adrenergic beta-Agonists Lipids Protein Transport 030104 developmental biology Adipose Tissue 030220 oncology & carcinogenesis Adipose triglyceride lipase biology.protein Cattle Female Animal Science and Zoology hormones hormone substitutes and hormone antagonists |
| Zdroj: | Domestic Animal Endocrinology. 61:62-76 |
| ISSN: | 0739-7240 |
| DOI: | 10.1016/j.domaniend.2017.06.001 |
| Popis: | Proper regulation of lipid metabolism is critical for preventing the development of metabolic diseases. It is clear that leptin plays a critical role in the regulation of energy homeostasis by regulating energy intake. However, leptin can also regulate energy homeostasis by inducing lipolysis in adipocytes, but it is unclear how the major lipases are involved in leptin-stimulated lipolysis. Therefore, the objectives of this study were to determine if (1) leptin acts directly to induce lipolysis in bovine adipocytes, (2) the potential lipases involved in leptin-induced lipolysis in bovine adipocytes, and (3) increases translocation of adipose triglyceride lipase (ATGL) and hormone sensitive lipase (HSL) during leptin-stimulated lipolysis in bovine stromal vascular cell-derived adipocytes. As hypothesized, leptin induced a lipolytic response (P = 0.02) in isolated adipocytes which was accompanied by an increase in phosphorylation of signal transducer and activator of transcription (STAT)3 (P = 0.03), a well-documented secondary messenger of leptin, and ATGL protein abundance (P0.01). Protein abundance of STAT3, perilipin, HSL, and phosphorylation of HSL by PKA and AMPK were not altered during leptin-stimulated lipolysis (P0.05). Immunostaining techniques were employed to determine the location of HSL and ATGL. Both lipases translocated to the lipid droplet after 2 h of exposure to isoproterenol (P0.02). However, only ATGL was translocated to the lipid droplet during leptin-stimulated lipolysis (P = 0.04), indicating ATGL may be the active lipase in leptin-stimulated lipolysis. In summary, leptin stimulates lipolysis in bovine adipocytes. The lack of phosphorylated HSL and translocation of HSL to the lipid droplet during leptin-stimulated lipolysis suggest minimal activity by PKA. Interestingly, leptin-stimulated lipolysis is accompanied by an increase in ATGL protein abundance and translocation to the lipid droplet, indicating its involvement in leptin-stimulated lipolysis either due to an increase in protein abundance or through a novel lipolytic cascade. |
| Databáze: | OpenAIRE |
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