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Shu H, Zhang J, Cheng D, Zhao X, Ma Y, Zhang C, Zhang Y, Jia Z, Liu Z. The Role of Proton-Coupled Amino Acid Transporter 2 (SLC36A2) in Cold-Induced Thermogenesis of Mice. Nutrients 2023; 15:3552. [PMID: 37630739 PMCID: PMC10458080 DOI: 10.3390/nu15163552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/07/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
Brown adipocytes mainly utilize glucose and fatty acids to produce energy, which play key roles in thermogenesis. Furthermore, brown adipocytes also utilize other substrates, such as amino acids, for energy expenditure in various conditions. Here, we report the new physiological roles of proton-coupled amino acid transporters, SLC36A2 and SLC36A3, on global energy metabolism. The relative mRNA expression levels of both Slc36a2 and Slc36a3 were all highest in brown adipose tissue. We then generated global Slc36a2 and Slc36a3 knockout mice to investigate their functions in metabolism. Neither loss of Slc36a2 nor Slc36a3 affected the body weight and body composition of the mice. Slc36a2 knockout mice exhibited increased oxygen consumption during the daytime. After cold treatment, inhibition of Slc36a2 significantly decreased the mass of brown adipose tissue compared to wildtype mice, while it lowered the expression level of Cpt1a. Moreover, the serum lipid levels and liver mass were also decreased in Slc36a2 knockout mice after cold treatment. On the contrary, Slc36a3 knockout impaired glucose tolerance and up-regulated serum LDL-cholesterol concentration. Thus, SLC36A2 and SLC36A3 play central and different roles in the energy metabolism of the mice.
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Affiliation(s)
| | | | | | | | | | | | | | - Zhihao Jia
- Cambridge-Suda Genomic Resource Center, Suzhou Medical College, Soochow University, Suzhou 215123, China; (H.S.); (J.Z.); (Y.M.); (Y.Z.)
| | - Zhiwei Liu
- Cambridge-Suda Genomic Resource Center, Suzhou Medical College, Soochow University, Suzhou 215123, China; (H.S.); (J.Z.); (Y.M.); (Y.Z.)
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Yoder PS, Castro JJ, Ruiz-Cortes T, Hanigan MD. Effects of varying extracellular amino acid concentrations on bidirectional amino acid transport and intracellular fluxes in mammary epithelial cells. J Dairy Sci 2021; 104:9931-9947. [PMID: 34176632 DOI: 10.3168/jds.2021-20187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/29/2021] [Indexed: 11/19/2022]
Abstract
Understanding the regulation of cellular AA uptake as protein supply changes is critical for predicting milk component yields because intracellular supplies partly regulate protein synthesis. Our objective was to evaluate cellular uptake and kinetic behavior of individual AA when cells are presented with varying extracellular AA supplies. Bovine primary mammary epithelial cells were grown to confluency and transferred to medium with an AA profile and concentration similar to that of plasma from dairy cows for 24 h. Treatments were 4 AA concentrations, 0.36, 2.30, 4.28, and 6.24 mM, which represented 16, 100, 186, and 271% of typical plasma AA concentrations, respectively, in lactating dairy cows. Twenty-four plates of cells (89.4 × 19.2 mm) were assigned to each treatment. Cells were first subjected to treatment medium enriched with 15N-labeled AA for 24 h and then incubated with treatment medium enriched with 13C-labeled AA for 0, 15, 60, 300, 900, 1,800, and 3,600 s. Intracellular free AA, intracellular protein-bound AA, and extracellular medium free AA were analyzed for concentrations and isotopic enrichment using gas chromatography-mass spectrometry. A dynamic, 12-pool model was fitted to the data for 14 AA to derive unidirectional uptake and efflux, protein turnover, transamination, oxidation, and synthesis. The derived concentration for half the maximal uptake (km) indicated no saturation of AA uptake at typical in vivo concentrations for 11 of the 14 AA. Arginine, Pro, and Val appeared to exhibit saturation kinetics. Net uptake of all essential AA except Phe was positive across treatments. Most nonessential AA exhibited negative net uptake values. Efflux of AA was quite high, with several AA exhibiting greater than 100% efflux of the respective influx. Intracellular pool turnover was rapid for most AA (e.g., 2 min for Arg), demonstrating plasticity in matching needs for protein translation to supplies. Intracellular AA concentrations increased linearly in response to treatment for most AA, whereas 9 AA exhibited quadratic responses. Amino acid uptake is responsive to varying extracellular supplies to maintain homeostasis. No saturation of uptake was evident for most AA, indicating that transporter capacity is likely not a limitation for most AA except possibly Arg, Val, and Pro in mammary epithelial cells.
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Affiliation(s)
- P S Yoder
- Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061; Perdue AgriBusiness LLC, Salisbury, MD 21804
| | | | - Tatiana Ruiz-Cortes
- Universidad de Antioquia, Faculty of Agricultural Sciences, Research Group Biogenesis, Medellin, Colombia, 050010
| | - M D Hanigan
- Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061.
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Ussar S, Lee KY, Dankel SN, Boucher J, Haering MF, Kleinridders A, Thomou T, Xue R, Macotela Y, Cypess AM, Tseng YH, Mellgren G, Kahn CR. ASC-1, PAT2, and P2RX5 are cell surface markers for white, beige, and brown adipocytes. Sci Transl Med 2015; 6:247ra103. [PMID: 25080478 DOI: 10.1126/scitranslmed.3008490] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
White, beige, and brown adipocytes are developmentally and functionally distinct but often occur mixed together within individual depots. To target white, beige, and brown adipocytes for diagnostic or therapeutic purposes, a better understanding of the cell surface properties of these cell types is essential. Using a combination of in silico, in vitro, and in vivo methods, we have identified three new cell surface markers of adipose cell types. The amino acid transporter ASC-1 is a white adipocyte-specific cell surface protein, with little or no expression in brown adipocytes, whereas the amino acid transporter PAT2 and the purinergic receptor P2RX5 are cell surface markers expressed in classical brown and beige adipocytes in mice. These markers also selectively mark brown/beige and white adipocytes in human tissue. Thus, ASC-1, PAT2, and P2RX5 are membrane surface proteins that may serve as tools to identify and target white and brown/beige adipocytes for therapeutic purposes.
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Affiliation(s)
- Siegfried Ussar
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA. Institute for Diabetes and Obesity, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Kevin Y Lee
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Simon N Dankel
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA. Department of Clinical Science, University of Bergen, 5020 Bergen, Norway. Hormone Laboratory, Haukeland University Hospital, 5020 Bergen, Norway
| | - Jeremie Boucher
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Max-Felix Haering
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Andre Kleinridders
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Thomas Thomou
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Ruidan Xue
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Yazmin Macotela
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Aaron M Cypess
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Yu-Hua Tseng
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA
| | - Gunnar Mellgren
- Department of Clinical Science, University of Bergen, 5020 Bergen, Norway. Hormone Laboratory, Haukeland University Hospital, 5020 Bergen, Norway
| | - C Ronald Kahn
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA 02215, USA.
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