@conference{
author = "Vidaković, Melita and Tolić, Anja and Marković, Jelena and Grdović, Nevena and Dinić, Svetlana and Uskoković, Aleksandra and Đorđević, Miloš and Arambašić Jovanović, Jelena and Mihailović, Mirjana and Poznanović, Goran and Martinet, Nadine",
year = "2013",
abstract = "Background and aims:
The CXC chemokine ligand 12 (CXCL12/SDF-1)
promotes the expression of the proliferative phenotype that improves the
resistance of pancreatic beta cells (b-cells) to diabetogenic stimuli. Our aim
was to demonstrate the positive impact of chemokine CXCL12 expression
on increased survival of b-cells, to provide a novel insight into the epigenetic
regulation of CXCL12 gene (
Cxcl12
) transcription and to initiate a screening
study designed to test whether certain compounds present in the Epigenetic
Compound Library (ECL-COST-TD0905) possess a DNMT1 inhibitory po-
tential.
Materials and methods:
The RIN-5F rat pancreatic b-cell line (wt), its coun-
terpart that possesses a stably integrated human gene for CXCL12 (#1) and
MIN6 cells were exposed to increasing concentrations of streptozotocin. The
prosurvival potential of CXCL12 was assessed by the viability assay (MTT).
For the DNA methylation studies, DNA was isolated from: rat RIN-5F wt and
#1 cells, rat Langerhans islets and mouse MIN6, NIH 3T3 wt and PARP-1
knockout cells. DNA methylation of the rat and mouse
Cxcl12
was assessed
using real-time methylation-specific PCR (MSP) with primers designed for
each CpG island predicted within the promoter, the first exon and intron of
Cxcl12
. Each component from ECL-COST-TD0905 was used at 15 μM con-
centration for demethylation studies (5-aza-2’-deoxycytidine, was used as
positive control).
Results:
Our results confirmed that the ιncreased presence of CXCL12 im-
proves pancreatic b-cell survival during oxidative stress induced by a dia-
betogenic stimulus. The CpG island analysis of the rat and mouse
Cxcl12
promoter, first exon and intron revealed the same number and very similar
distribution of CpG islands in both species. MSP showed that the CpG-rich
regions within the
Cxcl12
promoter, first exon and intron are semi-methyl-
ated in the rat Rin-5F cells. In the rat Langerhans islets, the core promoter is
unmethylated, while the first exon exhibited methylation of both alleles. In
mouse cells, large differences in methylation patterns of the core promoter
were observed: wt cells possess a unmethylated and PARP-1 knockout cells a
fully methylated core promoter. One of the eight analysed compounds from
the ECL-COST-TD0905 possesses potential to inhibit DNMT1
in vitro
.
Conclusion:
We confirmed that CXCL12 exerts a prosurvival effect on
pancreatic b-cells. The differences observed in the methylation status of the
Cxcl12
gene, points to decreased gene responsiveness to external stimuli. The
clear differences in the methylation status of the promoter and the first exon
in the rat insulinoma cell line and
ex vivo
isolated Langerhans islets have to
be underlined. Furthermore, observed hypermethylation of mouse
Cxcl12
in
PARP-1 knockout cells, points to the involvement of PARP-1 in the inhibition
of the methylation
in vivo.",
publisher = "Berlin, Heidelberg: Springer",
journal = "49th Annual Meeting of the European-Association-for-the-Study-of-Diabetes (EASD): Meeting Abstract; 2013 Sep 23-27; Barcelona, Spain",
title = "Epigenetic regulation of chemokine CXCL12 gene transcription influences its prosurvival effect on pancreatic beta cells",
volume = "56",
pages = "S191",
url = "https://hdl.handle.net/21.15107/rcub_ibiss_2475"
}
