Integrative transcriptomic analysis of pancreatic islets from patients with prediabetes/type 2 diabetes.

AIM: To identify new transcriptomic alterations in pancreatic islets associated with metabolic dysfunctions in people with prediabetes (PD)/type 2 diabetes (T2D). MATERIALS AND METHODS: We collected information from public data repositories T2D related microarray datasets from pancreatic islets. We identified Differential Expressed Genes (DEGs) in non-diabetic (ND) vs people with T2D in each study. To identify relevant DEGs in T2D, we selected those that varied consistently in the different studies for further meta-analysis and functional enrichment analysis. DEGs were also evaluated at the PD stage. RESULTS: A total of seven microarray datasets were collected and analysed to find the DEGs in each study and meta-analysis was performed with 245 ND and 96 T2D cases. We identified 55 transcriptional alterations potentially associated with specific metabolic dysfunctions in T2D. Meta-analysis showed that 87% of transcripts identified as DEGs (48 out of 55) were confirmed as having statistically significant up- or down-modulation in T2D compared to ND. Notably, nine of these DEGs have not been previously reported as dysregulated in pancreatic islets from people with T2D. Consistently, the most significantly enriched pathways were related to the metabolism and/or development/maintenance of ß-cells. Eighteen of the 48 selected DEGs (38%) showed an altered expression in islets from people with PD. CONCLUSIONS: These results provide new evidence to interpret the pathogenesis of T2D and the transition from PD to T2D. Further studies are necessary to validate its potential use for the development/implementation of efficient new strategies for the prevention, diagnosis/prognosis and treatment of T2D.

Increasing DNA Isolation Performance from Blood Cells Using a Modified Commercial Low-Cost Reagent.

BACKGROUND: Genomic studies facilitate comprehension of the pathophysiology, diagnosis, and treatment of chronic diseases. Such studies require sufficient and good quality DNA isolated from a large number of blood samples. This study attempts to obtain a high-quality genomic DNA isolated from a large number of blood samples using a simple and cheap method. METHODS: The EasyPure® Genomic DNA Kit (Transgen Biotech) was modified to increase the amount of DNA recovery: a few steps and two additional column elutions were added to the original manufacturer´s procedure. RESULTS: The amount of DNA isolated from frozen blood samples increased by an average of 56%. Its 260/280 ratio and electrophoretic mobility properties make it suitable for genomic studies. CONCLUSIONS: A relatively low-cost commercial column and a simple modification of the manufacturer´s protocol, provided a simple and cheap procedure to isolate high-quality DNA from a large number of blood samples suitable for genomic studies.

Streptonigrin induces delayed chromosomal instability involving interstitial telomeric sequences in Chinese hamster ovary cells.

We analyzed the induction of chromosomal aberrations in Chinese hamster ovary (CHO) cells exposed to the radiomimetic compound streptonigrin (SN), in order to determine whether interstitial telomeric sequences (ITSs) are involved in the long-term clastogenic effect of this antibiotic. CHO cells were treated with a single concentration of SN (100ng/ml), and the frequency of unstable chromosomal aberrations was determined at three times after treatment (18h, and 6 and 15 days) by using PNA-FISH with a pan-telomeric probe. Cytogenetic analysis revealed a higher frequency of aberrations at 18h and 6 days after treatment in SN-exposed cultures vs. untreated cultures. The percentage of damaged cells and the yield of SN-induced aberrations at 6 days after treatment increased on average twofold compared with the ones at 18h after treatment. Moreover, a significant decrease in the frequency of aberrations was observed in SN-exposed cells at 15 days after treatment, resulting in a frequency of aberrations significantly lower than the frequency of aberrations observed in the corresponding control cultures. These data indicate that SN induces delayed chromosomal instability in CHO cells, and that the in vitro clastogenic effect of this compound persists for at least 6 days but less than 15 days after treatment. In addition, we found that SN induces delayed ITSs instability, cytogenetically detectable as additional FISH signals and centromeric breaks involving dissociation of the telomeric signal 6 days after treatment. We propose that the delayed effect of SN on ITSs results from breakage of heterochromatic centromeric ITSs blocks and further insertion of these sequences at the sites of mono- or isochromatid breaks occurring at G2 or G1-S phases of the cell cycle, respectively, since most of the additional FISH signals were present as single or double dots, and located at interstitial sites of the involved chromosomes.