Changes in differential gene expression in fibroblast cells from patients with triple A syndrome under oxidative stress.

The triple A syndrome is a rare autosomal recessive disease caused by mutations in the AAAS gene, which encodes the nucleoporin ALADIN. Recently it was shown that ALADIN plays a role in the import of different factors into the nucleus, which prevent the cell from DNA damage and consecutive cell death under oxidative stress. In order to investigate the changes in differential gene expression in ALADIN-deficient or mutated cells under oxidative stress we used fibroblast cell cultures of triple A syndrome patients and compared these to controls. Analysis of 84 genes, which are associated with oxidative stress and antioxidant defense, showed that 7 genes were significantly and differentially regulated, namely BCL2/adenovirus E1B 19kD-interacting protein 3 (BNIP3), 24-dehydrocholesterol reduc-tase (DHCR24), dual specificity phosphatase 1 (DUSP1), forkhead box M1 (FOXM1), nudix-type motif 1 (NUDT1), prostaglandin-endoperoxide synthase 2 (PTGS2), and scavenger receptor class A, member 3 (SCARA3). Whereas in control cells the expression of DHCR24, FOXM1, NUDT1, and SCARA3 was decreased after paraquat treatment, the expression did not change significantly in patient cells. However, the basal expression of SCARA3 and BNIP3 was significantly higher in patient cells than in controls whereas PTGS2 was less expressed. Furthermore, after paraquat treatment the expression of BNIP3, DUSP1, and PTGS2 was significantly increased in control cells while in patient cells the increase of DUSP1 and PTGS2 expression was significantly reduced. With this work we confirm that cells of triple A patients show an altered induction or downregulation of genes associated with oxidative stress and antioxidant defense.

Characterisation of cholinesterase expression during murine embryonic stem cell differentiation.

It is already established that cholinesterases (ChEs) appear in every embryonic blastema at a very early stage of development, independently from innervation. Embryonic butyrylcholinesterase (BChE) is typically found in cells engaged in proliferation processes, while acetylcholinesterase (AChE) is expressed by cells undergoing morphogenetic processes. In order to better define the regulation of cholinesterases during development, we examined their expressions during in vitro differentiation of two murine embryonic stem cell lines by reverse transcription polymerase chain reaction, histochemistry and enzyme activity measurements. AChE and BChE activity and mRNA were present in the undifferentiated stem cells. To test whether the ChEs expression is regulated during differentiation, we employed the embryoid bodies (EBs) culture method, allowing the cells to differentiate, to then collect them at various stages in culture. Interestingly, phases of differentiation were accompanied by increased AChE transcripts; BChE expression was constant, decreasing at later differentiation stages. Cholinesterase activities showed corresponding patterns, with AChE activity increasing at later stages in culture and BChE slightly decreasing. Histochemistry revealed that AChE and BChE activities were mutually exclusive, being expressed by different cell subpopulations. Thus, we have demonstrated that mouse embryonic stem cells express cholinesterases, the enzymes are functional and their expression is regulated during differentiation. Therefore, it appears that their functions under these conditions are not related to synaptic transmission, but for the developmental processes.