engleski

MOAT3 (SLC22A8)and MOAT1 (SLC22A6) expression in mouse kidneys ; localization along the nephron and sex-differences

In mouse kidneys, various endogenous and exogenous organic anions are eliminated by the organic anion transporters mOat1 (Slc22a6) and mOat3 (Slc22a8), which reside in the basolateral membrane (BLM) of epithelial cells of different nephron segments. The exact localization of renal mOat1 in the proximal tubule (PT) has been previously verified in Oat1 knock-out (KO) mice. In contrast, mOat3 has been localized to the BLM of PT, the thick ascending limb of Henle, macula densa, distal tubules, and cortical collecting ducts, but its cell localization has not been properly validated in Oat3 KO mice. Furthermore, the sex-dependent expression of these transporters has been studied extensively at the mRNA level, while their protein expression has not been examined. Using Oat3 KO mice, we verified the specificity of anti-mOat3-antibodies and reinvestigated the localization of mOat3 along the mouse nephron by using a specific antibody. We also analysed the sex-dependent expression of renal mOat3 and mOat1 proteins and defined the hormone(s) responsible for these sex differences using adult wild-type males and females, and castrated males treated with various sex hormones. Cell localization and relative protein expression of mOat1 and mOat3 was analysed by Western blotting and fluorescence immunocytochemistry. The results indicate that mOat3 is localized exclusively to the BLM of PT, where it colocalizes with mOat1, exhibiting sex-dependent expression with an opposite pattern ; mOat3 expression is female-dominant due to androgen inhibition, while mOat1 expression is male-dominant due to androgen stimulation.

androgens; gender differences; immunocytochemistry; knock-out mice; membrane transporter; organic anions; proximal tubule; Western blotting

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