**Omega-3 Polyunsaturated Fatty Acids Inhibit the Function of Human URAT1, a Renal Urate Re-absorber**

**Hiroki Saito 1,2,**†**, Yu Toyoda 2,**† **, Tappei Takada 2,\*,**† **, Hiroshi Hirata 1, Ami Ota-Kontani 1, Hiroshi Miyata 2, Naoyuki Kobayashi 1, Youichi Tsuchiya 1 and Hiroshi Suzuki 2**


Received: 2 May 2020; Accepted: 27 May 2020; Published: 29 May 2020

**Abstract:** The beneficial e ffects of fatty acids (FAs) on human health have attracted widespread interest. However, little is known about the impact of FAs on the handling of urate, the end-product of human purine metabolism, in the body. Increased serum urate levels occur in hyperuricemia, a disease that can lead to gout. In humans, urate filtered by the glomerulus of the kidney is majorly re-absorbed from primary urine into the blood via the urate transporter 1 (URAT1)-mediated pathway. URAT1 inhibition, thus, contributes to decreasing serum urate concentration by increasing net renal urate excretion. Here, we investigated the URAT1-inhibitory e ffects of 25 FAs that are commonly contained in foods or produced in the body. For this purpose, we conducted an in vitro transport assay using cells transiently expressing URAT1. Our results showed that unsaturated FAs, especially long-chain unsaturated FAs, inhibited URAT1 more strongly than saturated FAs. Among the tested unsaturated FAs, eicosapentaenoic acid, α-linolenic acid, and docosahexaenoic acid exhibited substantial URAT1-inhibitory activities, with half maximal inhibitory concentration values of 6.0, 14.2, and 15.2 μM, respectively. Although further studies are required to investigate whether the ω-3 polyunsaturated FAs can be employed as uricosuric agents, our findings further confirm FAs as nutritionally important substances influencing human health.

**Keywords:** Docosahexaenoic acid; eicosapentaenoic acid; functional food; gout; human health; hyperuricemia; PUFA; SLC22A12; transporter; uric acid; uricosuric activity
