Renal Mesangial Cells Isolated from Sphingosine Kinase 2 Transgenic Mice Show Reduced Proliferation and are More Sensitive to Stress-Induced Apoptosis.

Beyer, Sandra; Schwalm, Stephanie; Pfeilschifter, Josef; Huwiler, Andrea (2018). Renal Mesangial Cells Isolated from Sphingosine Kinase 2 Transgenic Mice Show Reduced Proliferation and are More Sensitive to Stress-Induced Apoptosis. Cellular physiology and biochemistry, 47(6), pp. 2522-2533. Karger 10.1159/000491625

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BACKGROUND/AIMS Sphingosine 1-phosphate (S1P) is considered as a key molecule regulating various cell functions including cell growth and death. It is produced by two sphingosine kinases (SK) denoted as SK-1 and SK-2. Whereas SK-1 has been extensively studied and has been appointed a role in promoting cell growth, the function of SK-2 is controversial, and both pro-proliferative and pro-apoptotic functions have been suggested. In this study we investigated whether renal mesangial cells isolated from transgenic mice overexpressing the human Sphk2 gene (hSK2-tg) showed an altered cell response towards growth-inducing and apoptotic stimuli. METHODS hSK2-tg mice were generated by using a Quick KnockinR strategy. Renal mesangial cells were isolated by a differential sieving method and further cultivated in vitro. Lipids were quantified by mass spectrometry. Protein expression was determined by Western blot analysis, cell proliferation was determined by 3H-thymidine incorporation, and apoptosis was determined by a DNA fragmentation ELISA. RESULTS We show here that kidneys and mesangial cells from hSK2-tg mice express the hSK2 as well as the endogenous mouse mSK2. hSK2 and mSK2 predominantly resided in the cytosol of quiescent transgenic cells. However, S1P accumulated strongly in the nucleus and only minimally in the cytosol of transgenic cells. Functionally, hSK2-tg cells proliferated less than control cells under normal growth conditions and were also more sensitive towards stress-induced apoptosis. On the molecular level, this was reflected by reduced ERK and Akt/PKB activation, and upon staurosporine treatment, by a sensitized mitochondrial pathway as manifested by reduced anti-apoptotic Bcl-XL expression and increased cleavage of caspase-9, downstream caspase-3 and PARP-1. CONCLUSION Altogether, these data demonstrate that SK-2 exerts an antiproliferative and apoptosis-sensitizing effect in renal mesangial cells which suggests that selective inhibitors of SK-2 may promote proliferation and reduce apoptosis and this may have impact on the outcome of proliferation-associated diseases such as mesangioproliferative glomerulonephritis.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Pharmacology

UniBE Contributor:

Schwalm, Stephanie and Huwiler, Andrea

Subjects:

600 Technology > 610 Medicine & health

ISSN:

1015-8987

Publisher:

Karger

Language:

English

Submitter:

Sabrina Cookman

Date Deposited:

10 Sep 2018 10:38

Last Modified:

24 Oct 2019 19:24

Publisher DOI:

10.1159/000491625

PubMed ID:

29991026

Uncontrolled Keywords:

Apoptosis Autophagy Mesangial cells Proliferation S1P Transgenic SK-2 mice

BORIS DOI:

10.7892/boris.119884

URI:

https://boris.unibe.ch/id/eprint/119884

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