Extracellular nucleotides induce migration of renal mesangial cells by upregulating sphingosine kinase-1 expression and activity

Klawitter, S; Hofmann, L P; Pfeilschifter, J; Huwiler, A (2007). Extracellular nucleotides induce migration of renal mesangial cells by upregulating sphingosine kinase-1 expression and activity. British journal of pharmacology, 150(3), pp. 271-80. Oxford: Wiley-Blackwell 10.1038/sj.bjp.0706983

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BACKGROUND AND PURPOSE: Extracellular nucleotides act as potent mitogens for renal mesangial cells (MC). In this study we determined whether extracellular nucleotides trigger additional responses in MCs and the mechanisms involved. EXPERIMENTAL APPROACH: MC migration was measured after nucleotide stimulation in an adapted Boyden-chamber. Sphingosine kinase-1 (SK-1) protein expression was detected by Western blot analysis and mRNA expression quantified by real-time PCR. SK activity was measured by an in vitro kinase assay using sphingosine as substrate. KEY RESULTS: Nucleotide stimulation caused biphasic activation of SK-1, but not SK-2. The first peak occurred after minutes of stimulation and was followed by a second delayed peak after 4-24 h of stimulation. The delayed activation of SK-1 is due to increased SK-1 mRNA steady-state levels and de novo synthesis of SK-1 protein, and depends on PKC and the classical MAPK cascade. To see whether nucleotide-stimulated cell responses require SK-1, we selectively depleted SK-1 from cells by using small-interference RNA (siRNA). MC migration is highly stimulated by ATP and UTP; this is mimicked by exogenously added S1P. Depletion of SK-1 by siRNA drastically reduced the effect of ATP and UTP on cell migration but not on cell proliferation. Furthermore, MCs isolated from SK-1-deficient mice were completely devoid of nucleotide-induced migration. CONCLUSIONS AND IMPLICATIONS: These data show that extracellular nucleotides besides being mitogenic also trigger MC migration and this cell response critically requires SK-1 activity. Thus, pharmacological intervention of SK-1 may have impacts on situations where MC migration is important such as during inflammatory kidney diseases.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Pharmacology
UniBE Contributor:	Huwiler, Andrea
ISSN:	0007-1188
ISBN:	17200676
Publisher:	Wiley-Blackwell
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 14:48
Last Modified:	05 Dec 2022 14:15
Publisher DOI:	10.1038/sj.bjp.0706983
PubMed ID:	17200676
Web of Science ID:	000244386800005
URI:	https://boris.unibe.ch/id/eprint/20235 (FactScience: 3422)