PMID- 29772789 OWN - NLM STAT- MEDLINE DCOM- 20180926 LR - 20181114 IS - 1422-0067 (Electronic) IS - 1422-0067 (Linking) VI - 19 IP - 5 DP - 2018 May 17 TI - Downregulation of the S1P Transporter Spinster Homology Protein 2 (Spns2) Exerts an Anti-Fibrotic and Anti-Inflammatory Effect in Human Renal Proximal Tubular Epithelial Cells. LID - 10.3390/ijms19051498 [doi] LID - 1498 AB - Sphingosine kinase (SK) catalyses the formation of sphingosine 1-phosphate (S1P), which acts as a key regulator of inflammatory and fibrotic reactions, mainly via S1P receptor activation. Here, we show that in the human renal proximal tubular epithelial cell line HK2, the profibrotic mediator transforming growth factor beta (TGFbeta) induces SK-1 mRNA and protein expression, and in parallel, it also upregulates the expression of the fibrotic markers connective tissue growth factor (CTGF) and fibronectin. Stable downregulation of SK-1 by RNAi resulted in the increased expression of CTGF, suggesting a suppressive effect of SK-1-derived intracellular S1P in the fibrotic process, which is lost when SK-1 is downregulated. In a further approach, the S1P transporter Spns2, which is known to export S1P and thereby reduces intracellular S1P levels, was stably downregulated in HK2 cells by RNAi. This treatment decreased TGFbeta-induced CTGF and fibronectin expression, and it abolished the strong induction of the monocyte chemotactic protein 1 (MCP-1) by the pro-inflammatory cytokines tumor necrosis factor (TNF)alpha and interleukin (IL)-1beta. Moreover, it enhanced the expression of aquaporin 1, which is an important water channel that is expressed in the proximal tubules, and reverted aquaporin 1 downregulation induced by IL-1beta/TNFalpha. On the other hand, overexpression of a Spns2-GFP construct increased S1P secretion and it resulted in enhanced TGFbeta-induced CTGF expression. In summary, our data demonstrate that in human renal proximal tubular epithelial cells, SK-1 downregulation accelerates an inflammatory and fibrotic reaction, whereas Spns2 downregulation has an opposite effect. We conclude that Spns2 represents a promising new target for the treatment of tubulointerstitial inflammation and fibrosis. FAU - Blanchard, Olivier AU - Blanchard O AD - Institute of Pharmacology, University of Bern, Inselspital, INO-F, CH-3010 Bern, Switzerland. olivier.blanchard@pki.unibe.ch. FAU - Stepanovska, Bisera AU - Stepanovska B AD - Institute of Pharmacology, University of Bern, Inselspital, INO-F, CH-3010 Bern, Switzerland. bisera.stepanovska@pki.unibe.ch. FAU - Starck, Manuel AU - Starck M AD - Institute of Pharmacology, University of Bern, Inselspital, INO-F, CH-3010 Bern, Switzerland. manuel.starck@pki.unibe.ch. FAU - Erhardt, Martin AU - Erhardt M AD - Institute of Pharmacology, University of Bern, Inselspital, INO-F, CH-3010 Bern, Switzerland. martin.erhardt@pki.unibe.ch. FAU - Romer, Isolde AU - Romer I AD - Institute of General Pharmacology and Toxicology, University Hospital Frankfurt am Main, Goethe-University, Theodor-Stern Kai 7, D-60590 Frankfurt am Main, Germany. I.Roemer@em.uni-frankfurt.de. FAU - Meyer Zu Heringdorf, Dagmar AU - Meyer Zu Heringdorf D AUID- ORCID: 0000-0003-1246-9677 AD - Institute of General Pharmacology and Toxicology, University Hospital Frankfurt am Main, Goethe-University, Theodor-Stern Kai 7, D-60590 Frankfurt am Main, Germany. heringdorf@med.uni-frankfurt.de. FAU - Pfeilschifter, Josef AU - Pfeilschifter J AD - Institute of General Pharmacology and Toxicology, University Hospital Frankfurt am Main, Goethe-University, Theodor-Stern Kai 7, D-60590 Frankfurt am Main, Germany. Pfeilschifter@em.uni-frankfurt.de. FAU - Zangemeister-Wittke, Uwe AU - Zangemeister-Wittke U AD - Institute of Pharmacology, University of Bern, Inselspital, INO-F, CH-3010 Bern, Switzerland. uwe.zangemeister@pki.unibe.ch. FAU - Huwiler, Andrea AU - Huwiler A AUID- ORCID: 0000-0003-1615-5691 AD - Institute of Pharmacology, University of Bern, Inselspital, INO-F, CH-3010 Bern, Switzerland. huwiler@pki.unibe.ch. LA - eng PT - Journal Article DEP - 20180517 PL - Switzerland TA - Int J Mol Sci JT - International journal of molecular sciences JID - 101092791 RN - 0 (Anion Transport Proteins) RN - 0 (Biomarkers) RN - 0 (Lysophospholipids) RN - 0 (RNA, Messenger) RN - 0 (RNA, Small Interfering) RN - 0 (Spns2 protein, human) RN - 26993-30-6 (sphingosine 1-phosphate) RN - NGZ37HRE42 (Sphingosine) SB - IM MH - Anion Transport Proteins/*genetics MH - Biomarkers MH - Cells, Cultured MH - Down-Regulation MH - Epithelial Cells/*metabolism/pathology MH - Fibrosis MH - Fluorescent Antibody Technique MH - *Gene Expression Regulation MH - Gene Knockdown Techniques MH - Humans MH - Inflammation MH - Kidney Tubules, Proximal/*metabolism/pathology MH - Lysophospholipids/metabolism MH - Podocytes/metabolism MH - RNA Interference MH - RNA, Messenger/genetics MH - RNA, Small Interfering/genetics MH - Sphingosine/analogs & derivatives/metabolism PMC - PMC5983760 OTO - NOTNLM OT - CTGF OT - aquaporin 1 OT - fibrosis OT - human renal proximal tubular epithelial cells OT - inflammation OT - sphingosine 1-phosphate OT - sphingosine kinase 1 OT - spinster homology protein 2 (Spns2) COIS- The authors declare no conflict of interest. EDAT- 2018/05/19 06:00 MHDA- 2018/09/27 06:00 PMCR- 2018/05/01 CRDT- 2018/05/19 06:00 PHST- 2018/04/20 00:00 [received] PHST- 2018/05/14 00:00 [revised] PHST- 2018/05/15 00:00 [accepted] PHST- 2018/05/19 06:00 [entrez] PHST- 2018/05/19 06:00 [pubmed] PHST- 2018/09/27 06:00 [medline] PHST- 2018/05/01 00:00 [pmc-release] AID - ijms19051498 [pii] AID - ijms-19-01498 [pii] AID - 10.3390/ijms19051498 [doi] PST - epublish SO - Int J Mol Sci. 2018 May 17;19(5):1498. doi: 10.3390/ijms19051498.