Assessment of the Role of Renal Organic Anion Transporters in Drug-Induced Nephrotoxicity

In the present review we have attempted to assess the involvement of the organic anion transporters OAT1, OAT2, OAT3, and OAT4, belonging to the SLC22 family of polyspecific carriers, in drug-induced renal damage in humans. We have focused on drugs with widely recognized nephrotoxic potential, which have previously been reported to interact with OAT family members, and whose underlying pathogenic mechanism suggests the participation of tubular transport. Thus, only compounds generally believed to cause kidney injury either by means of direct tubular toxicity or crystal nephropathy have been considered. For each drug, or class of agents, the evidence for actual transport mediated by individual OATs under in vivo conditions is discussed. We have then examined their role in the context of other carriers present in the renal proximal tubule sharing certain substrates with OATs, as these are critical determinants of the overall contribution of OAT-dependent transport to intracellular accumulation and transepithelial drug secretion, and thus the impact it may have in drug-induced nephrotoxicity

Contrasting effects of diclofenac and ibuprofen on active imatinib uptake into leukaemic cells

BACKGROUND: The human organic cation transporter-1 (OCT-1) is the primary active protein for imatinib uptake into target BCR-ABL-positive cells. Non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used by chronic myeloid leukaemia (CML) patients on imatinib to manage musculoskeletal complaints. METHODS: Here we investigated the impact of NSAIDs on functional activity of the OCT-1 (OCT-1 activity; OA) in CML cells. RESULTS: Although ten of twelve NSAIDs tested had no significant impact on OA (P>0.05), we observed increased OA (27% increase in K562; 22% increase in KU812 cells, P<0.05) and reduced IC50(imatinib) when treated with diclofenac. Co-incubation with imatinib and diclofenac resulted in a significantly lower viable cell number compared with imatinib alone. In contrast, ibuprofen led to a significant decrease in OA, an increase in IC50(imatinib) and thus reduced the cytotoxicity of imatinib. In primary CML samples, diclofenac significantly increased OA, particularly in patients with low OA (<4 ng per 200 000 cells), and significantly decreased IC50(imatinib). Ibuprofen induced significant decreases in OA in CML samples and healthy donors. CONCLUSION: On the basis of the expected impact of these two drugs on OA, ibuprofen should be avoided in combination with imatinib. Further studies are warranted regarding the potential benefit of diclofenac to improve OA in a clinical setting.J. Wang, T.P. Hughes, C.H. Kok, V.A. Saunders, A. Frede, K. Groot-Obbink, M. Osborn, A.A. Somogyi, R.J. D’Andrea and D.L. Whit

Surface phase diagram of CsSnI3_3 from first-principles calculations

CsSnI$_3$ is widely studied as an environmentally friendly Pb-free perovskite material for optoelectronic device applications. To further improve material and device performance, it is important to understand the surface structures of CsSnI$_3$. We generate surface structures with various stoichiometries, perform density functional theory calculations to create phase diagrams of the CsSnI$_3$ (001), (110), and (100) surfaces, and determine the most stable surfaces under a wide range of Cs, Sn, and I chemical potentials. Under I-rich conditions, surfaces with Cs vacancies are stable, which lead to partially occupied surface states above the valence band maximum. Under I-poor conditions, we find the stoichiometric (100) surface to be stable under a wide region of the phase diagram, which does not have any surface states and can contribute to long charge carrier lifetimes. Consequently, the I-poor (Sn-rich) conditions will be more beneficial to improve the device performance

Interactions of Human- and Rat-Organic Anion Transporters With Pravastatin and Cimetidine

We have elucidated the interactions of human and rat organic anion transporters (hOATs and rOATs) with pravastatin and cimetidine. Pravastatin inhibited hOAT1/rOAT1, hOAT2/rOAT2, hOAT3/rOAT3, and hOAT4. The mode of inhibition was noncompetitive for hOAT1 and hOAT2, whereas it was competitive for hOAT3 and hOAT4. Cimetidine also inhibited hOAT1/rOAT1, hOAT3/rOAT3, and hOAT4. The mode of inhibition was a combination of competitive and noncompetitive manners for hOAT1, whereas it was competitive for hOAT3. The effects of OAT inhibitors on OAT1, OAT2, and OAT3 exhibited some but not so remarkable interspecies differences between humans and rats. In conclusion, we have characterized pravastatin and cimetidine as OAT inhibitors. Keywords:: organic anion transporter, pravastatin, cimetidin

Computational Design of a Strain-Induced 2D/2D g‑C₃N₄/ZnO S‑Scheme Heterostructured Photocatalyst for Water Splitting

Electron–hole recombination is one of the major issues inhibiting practical use of photocatalysts for water splitting to generate clean hydrogen energy. Engineering a heterostructure with an S-scheme heterojunction has been reported to promote e–h separation and maximize potential of photogenerated charge carriers, which, in turn, dramatically improve photocatalytic activity. Herein, based on density functional calculations, we proposed a design of a 2D/2D g-C3N4/ZnO heterostructure to achieve an S-scheme heterojunction with high catalytic activity toward the overall water splitting reaction. We find that the heterostructure constructed from high tensile strain of the ZnO monolayer and the equilibrium g-C3N4 monolayer exhibits an S-scheme heterojunction. The built-in electric field generated at the interface effectively separates electrons to locate at the g-C3N4 side and holes at the ZnO side leading to lower e–h recombination. The heterostructure improves sunlight utilization where its absorption edge is red-shifted into the visible-light region with a higher absorption coefficient when compared to that of individual monolayers. In addition, the mechanistic study reveals that potential of holes at the valence band of the ZnO side can overcome the potential limiting step of the oxygen evolution reaction, while the hydrogen evolution reaction prefers to occur at the g-C3N4 side, which is also where the electrons are accumulated. Our study demonstrates how we can rationally design high-performance 2D/2D heterostructure photocatalysts for overall water splitting based on first-principles modeling