Adefovir accumulation and nephrotoxicity in renal interstitium: Role of organic anion transporters of kidney

Examination of the emerging role of transporters in the assessment of nephrotoxicity

INTRODUCTION

The kidney is vulnerable to various injuries based on its function in the elimination of many xenobiotics, endogenous substances and metabolites. Since transporters are critical for the renal elimination of those substances, it is urgent to understand the emerging role of transporters in nephrotoxicity.

AREAS COVERED

This review summarizes the contribution of major renal transporters to nephrotoxicity induced by some drugs or toxins; addresses the role of transporter-mediated endogenous metabolic disturbances in nephrotoxicity; and discusses the advantages and disadvantages of in vitro models based on transporter expression and function.

EXPERT OPINION

Due to the crucial role of transporters in the renal disposition of xenobiotics and endogenous substances, it is necessary to further elucidate their renal transport mechanisms and pay more attention to the underlying relationship between the transport of endogenous substances and nephrotoxicity. Considering the species differences in the expression and function of transporters, and the low expression of transporters in general cell models, in vitro humanized models, such as humanized 3D organoids, shows significant promise in nephrotoxicity prediction and mechanism study.

The Extract of Sonneratia apetala Leaves and Branches Ameliorates Hyperuricemia in Mice by Regulating Renal Uric Acid Transporters and Suppressing the Activation of the JAK/STAT Signaling Pathway

Sonneratia apetala Buch-Ham., an exotic mangrove species with antidiabetic, antibacterial, and antioxidant capacities, mainly distributes in the southeast coastal areas in China. The present work investigated the protective effects of Sonneratia apetala leaves and branches extraction (SAL) on hyperuricemia (HUA) in mice. Potassium oxonate (PO) and hypoxanthine (HX) were used to establish the HUA model by challenge for consecutive 7 days. Results revealed that SAL inhibited the increases in kidney weight and index compared to the vehicle group. Meanwhile, SAL significantly decreased the levels of uric acid (UA), creatinine (CRE), and blood urea nitrogen (BUN) in serum. Additionally, SAL inhibited the activity of xanthine oxidase (XOD) in the liver. SAL ameliorated PO- and HX-induced histopathological changes. Moreover, it regulated oxidative stress markers including malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD) activity, and glutathione (GSH) content. Also, SAL inhibited the increases in renal levels of interleukin-6 (IL-6), interleukin-18 (IL-18), interleukin-1β (IL-1β), tumor necrosis factor (TNF-α), monocyte chemotactic protein 1 (MCP-1), and transforming growth factor-β (TGF-β). SAL remarkably reduced suppressor of cytokine signaling 3 (SOCS3), Janus kinase 2 (JAK2), and subsequent phosphorylation of signal transducer and activator of transcription 3 (STAT3) expression. In addition, SAL inhibited the activation of nuclear factor kappa-B (NF-κB) in the kidney. Furthermore, SAL protected against HUA by regulating renal UA transporters of organic anion transporter (OAT1), urate reabsorption transporter 1 (URAT1), and glucose transporter 9 (GLUT9). These findings suggested that SAL ameliorated HUA by inhibiting the production of uric acid and enhancing renal urate excretion, which are related to oxidative stress and inflammation, and the possible molecular mechanisms include its ability to inhibit the JAK/STAT signaling pathway. Thus, SAL might be developed into a promising agent for HUA treatments.