Adipocytes take up long chain FAs through diffusion and protein-mediated transport, whereas FA efflux is considered to occur by diffusion. To identify potential membrane proteins that are involved in regulating FA flux in adipocytes, the expression levels of 55 membrane transporters without known function were screened in subcutaneous adipose samples from obese patients before and after bariatric surgery using branched DNA methodology. Among the 33 solute carrier (SLC) transporter family members screened, the expression of 14 members showed significant changes before and after bariatric surgery. One of them, Slc43a3, increased about 2.5-fold after bariatric surgery. Further investigation demonstrated that Slc43a3 is highly expressed in murine adipose tissue and induced during adipocyte differentiation in primary preadipocytes and in OP9 cells. Knockdown of Slc43a3 with siRNA in differentiated OP9 adipocytes reduced both basal and forskolin-stimulated FA efflux, while also increasing FA uptake and lipid droplet accumulation. In contrast, overexpression of Slc43a3 decreased FA uptake in differentiated OP9 cells and resulted in decreased lipid droplet accumulation. Therefore, Slc43a3 seems to regulate FA flux in adipocytes, functioning as a positive regulator of FA efflux and as a negative regulator of FA uptake.
Bibliographical noteFunding Information:
This work was supported by U.S. Department of Veterans Affairs (Biomedical Laboratory Research Development Program) Merit Review Awards I01BX001923 (S.A.) and I01BX000398 (F.B.K.) and Senior Research Career Scientist Award IK6B004200 (S.A.) and National Institutes of Health Grants P30DK116074 (F.B.K) and DK053189 (D.A.B.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The authors declare that they have no conflicts of interest with the contents of this article. Manuscript received 25 July 2019 and in revised form 3 March 2020. Published, JLR Papers in Press, March 26, 2020 DOI https://doi.org/10.1194/jlr.RA119000294
- Adipose metabolism
- Fatty acid efflux
- Fatty acid uptake
- Lipid droplet
- Membrane transporters
- Solute carrier family 43 member 3
PubMed: MeSH publication types
- Journal Article
- Research Support, U.S. Gov't, Non-P.H.S.
- Research Support, N.I.H., Extramural