Transcriptome analysis identifies activated signaling pathways and regulated ABC transporters and solute carriers after hyperosmotic stress in renal MDCK I cells.

Hyperosmolality is found under physiological conditions in the kidneys, whereas hyperosmolality in other tissues may be associated with pathological conditions. In such tissues an association between inflammation and hyperosmolality has been suggested. During hyperosmotic stress, an important phenomenon is upregulation of solute carriers (SLCs). We hypothesize that hyperosmolality affects the expression of many SLCs as well as ABC transporters. Through RNA-sequencing and topological pathway analysis, the cell cycle, the cytokine-cytokine receptor interaction pathway, and the chemokine-signaling pathway were significantly activated in MDCK I cells after hyperosmotic treatment (Δ200 mOsm) with raffinose or NaCl. 9065, 8052 and 5018 genes were significantly regulated by raffinose, NaCl or urea supplementation (500 mOsm), respectively, compared to control (300 mOsm). Cytokines, that have not previously been associated with hyperosmolality, were identified. We further provide an overview of transport proteins that could be of relevance in tissues exposed to hyperosmolality. Especially Slc5a8 was found highly up-regulated.