PODO/TERT256 - A promising human immortalized podocyte cell line and its potential use for in vitro research at different oxygen levels.

Podocytes are of key interest for the prediction of nephrotoxicity as they are especially sensitive to toxic insults due to their central role in the glomerular filtration apparatus. However, currently, prediction of nephrotoxicity in humans remains insufficiently reliable, thus highlighting the need for advanced in vitro model systems using human cells with improved prediction capacity. Recent approaches for refining in vitro model systems focus on closely replicating physiological conditions as observed under the in vivo situation typical of the respective nephron section of interest.

Physiological oxygen and co-culture with human fibroblasts facilitate in vivo-like properties in human renal proximal tubular epithelial cells.

Reliable prediction of compound mediated nephrotoxicity in humans is still unsatisfactory irrespective of the recent advancements in in silico, in vitro and in vivo models. Therefore, current in vitro approaches need refinement to better match the human in vivo situation, specifically with regard to the potential influence of other cell types (e.g.

Functional transepithelial transport measurements to detect nephrotoxicity in vitro using the RPTEC/TERT1 cell line.

The kidney is a frequent target for organ-specific toxicity as a result of its primary function in controlling body fluids, for example, via resorption of amino acids, peptides, nutrients, ions, xenobiotics and water from the primary urine as well as excretion of metabolic waste products and hydrophilic and amphiphilic xenobiotics. Compounds exhibiting dose-limiting nephrotoxicity include drugs from highly diverse classes and chemical structures, e.g.

Canagliflozin mediated dual inhibition of mitochondrial glutamate dehydrogenase and complex I: an off-target adverse effect.

Recent FDA Drug Safety Communications report an increased risk for acute kidney injury in patients treated with the gliflozin class of sodium/glucose co-transport inhibitors indicated for treatment of type 2 diabetes mellitus. To identify a potential rationale for the latter, we used an in vitro human renal proximal tubule epithelial cell model system (RPTEC/TERT1), physiologically representing human renal proximal tubule function. A targeted metabolomics approach, contrasting gliflozins to inhibitors of central carbon metabolism and mitochondrial function, revealed a double mode of action for canagliflozin, but not for its analogs dapagliflozin and empagliflozin.

RPTEC/TERT1 cells form highly differentiated tubules when cultured in a 3D matrix.

The proximal tubule is the primary site for renal solute reabsorption and secretion and thus a main target for drug-induced toxicity. Current nonclinical methods using 2D cell cultures are unable to fully recapitulate clinical drug responses mainly due to limited in vitro functional lifespan. Since extracellular matrices are known to be key regulators of cell development, culturing cells on classic 2D plastic surfaces inevitably results in loss of differentiation.