Hilal Arikoglu

The Adiponectin variants contribute to the genetic background of type 2 diabetes in Turkish population

Adiponectin, an adipose tissue specific protein encoded by the Adiponectin gene, modulates insulin sensitivity and plays an important role in regulating energy homeostasis. Many studies have shown that single nucleotide polymorphisms (SNPs) in the Adiponectin gene are associated with low plasma adiponectin levels, insulin resistance and an increased risk of type 2 diabetes mellitus. The aim of the present study was to evaluate the contribution of the Adiponectin gene polymorphisms in genetic background of type 2 diabetes in a Turkish population. In total, 169 unrelated and non-obese diabetic patients and 119 age- and BMI-matched non-diabetic individuals with no family history of diabetes were enrolled in this study. We detected a significant association between type 2 diabetes and two SNPs: SNP -11391G>A, which is located in the promoter region of the Adiponectin gene, and SNP +276G>T, which is found in intron 2 of the gene (P<0.05). The silence SNP G15G (+45T>G) in exon 1 and SNP +349A>G in intron 2 also showed a weak association with type 2 diabetes (P=0.06 and P=0.07, respectively), while SNPs -3971A>G in intron 1 and Y111H, R112C and H241P in exon 3 showed no association (P>0.05). In conclusion, these findings suggest that Adiponectin gene polymorphisms might be effective on susceptibility for type 2 diabetes development which emerged from the interactions between multiple genes, variants and environmental factors.

Mitochondrial divergence between three cytotypes of the Anatolian Mole Rat, Nannospalax xanthodon (Nordmann, 1840)

Abstract The Blind Mole Rats of Anatolia (Nannospalax xanthodon (Nordmann, 1840)) are characterised by prolific chromosomal diversification. While the geographic distribution of various cytotypes is well documented, opinions on their taxonomic ranking varies amongst authorities. A partial sequence (630 bp) of mitochondrial cytochrome b gene in 13 Blind Mole Rats from the Konya basin, central Anatolia, which represented three distinct cytotypes (2n=40, 58, and 60) yielded nine cyt b haplotypes. Phylogenetic reconstructions recognized three well supported lineages which matched diploid number counts. Genetic divergences between cytotypes were high (K2P between 8.16% ± 1.19 and 11.33% ± 1.42) and application of the 2% divergence rate to the net divergence estimates suggests their divergence about 3.84 and 5.43 Mya (95% confidence interval=1.53–8.19 Mya). If one would rely on genetic operational criteria in species delimitation, there would be little doubt that the three Nannospalax cytotypes analysed in this study belong to distinct allopatric species. Before translating the results into formal taxonomy, more genetic information should be acquired on different Nannospalax cytotypes occupying the eastern Mediterranean.

IRS1 gene polymorphisms Gly972Arg and Ala513Pro are not associated with insulin resistance and type 2 diabetes risk in non-obese Turkish population.

Insulin receptor substrate 1 (IRS1), plays a critical role in insulin signaling and its control has an important place in the development of insulin resistance. The tyrosine phosphorylation of IRS1 serves as docking molecules for downstream effectors such as Phosphatidylinositol 3-kinase and phosphotyrosine phosphatase-2. We focused on the Gly972Arg and Ala513Pro variants of the IRS1 gene, since these specific allelic variants are located near the Tyr-Met-X-Met (YMXM) motifs around Tyr987 and Tyr612. Thus, we aimed to investigate the effects of Gly972Arg/Ala513Pro polymorphisms in IRS1 gene on development of insulin resistance and the risk of type 2 diabetes in a non-obese Turkish population. This work included 306 individuals comprising 178 subjects with type 2 diabetes and 128 healthy subjects matched for body mass index. Gly972Arg/Ala513Pro polymorphisms had no effect on type 2 diabetes risk and its phenotypes (P > 0.05). Although IRS1 gene and its variants are associated with type 2 diabetes and insulin resistance in several studies worldwide, our data showed that there is no association between Gly972Arg and Ala513Pro variants in IRS1 and disease in Turkish population.

Association Between the T-593A and C6982T Polymorphisms of the Osteopontin Gene and Risk of Developing Nephrolithiasis

BACKGROUND AND AIMS Increased synthesis of several urinary proteins including osteopontin (OPN) has been shown to be associated with stone formation within the urinary tract. The objective of this study was to analyze the genotype distributions and allele frequencies for OPN gene promoter T-593A and C6982T (in exon 7) polymorphisms among patients with kidney stones. METHODS In this case-control study, the study group consisted of 121 patients with radiologically confirmed nephrolithiasis. Genomic DNA from patients and control cases (n = 100) was analyzed by single-strand conformation polymorphism method and nucleotide sequence analysis. RESULTS Homozygous carriers of the T-593T genotype were more frequent, but carriers of the A-593A genotype were less frequent in patients than in controls. There was also an increase in -593T allele (88% in patients vs. 79% in controls) and decrease in -593A allele frequencies (21% in control vs. 12% in patients) in the nephrolithiasis groups (p = 0.013). The carriers of C6982C genotype were less frequent, but marked increases in T6982T genotype (25.6% in patients vs. 7% in controls, p = 0.001) and 6982T allele frequency (53.3% in patients vs. 37.5% in controls, p = 0.001) were noted in patients of Turkish ancestry. CONCLUSIONS These results are the first to demonstrate the existence of T-593A promoter polymorphism of the OPN gene and significant association with risk of developing nephrolithiasis. Our results showed marked associations between polymorphisms (C6982T and T-593A) of the OPN gene and the stone-forming phenotypes in the Turkish population.

Investigation of juglone effects on metastasis and angiogenesis in pancreatic cancer cells.

Juglone, a natural component, is shown to have cytotoxic and apoptotic effects in several cancer cell lines. However, little is known about its effects on invasion and metastasis. In this study, we aimed to determine the antimetastatic effect of juglone in the BxPC-3 and PANC-1 pancreatic cancer cell lines. Cytotoxic effect of juglone was evaluated by using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) test. The cells were treated with juglone at <IC50 doses (5, 10, 15 and 20μM ) for 24h. After the cell adhesion and invasion analysis, expression profiles of the MMP-2, MMP-9 and Phactr-1 genes were determined by qPCR. The IC50 dose of juglone was found to be 21.05μM in the BxPC-3 cell line and 21.25μM in the PANC-1 cell line for 24h. According to the cell adhesion and invasion analysis, treatment of juglone for 24h reduced the adhesion and invasion features of pancreatic cancer cells. A significant reduction of MMP-2, MMP-9 and Phactr-1 expressions was observed in pancreatic cancer cells after the treatment of juglone at <IC50 doses. By this study, it has been shown for the first time that juglone inhibits cell invasion and metastasis in pancreatic cancer line and can be evaluated as an effective anticancer agent in pancreatic cancer.

Effects of Single Nucleotide Polymorphisms in KATP Channel Genes on Type 2 Diabetes in a Turkish Population

BACKGROUND AND AIMS ATP-sensitive potassium (K(ATP)) channels of pancreatic β-cells play a key role in glucose-stimulated insulin secretion mechanism. The Kir6.2 protein, forming the K(ATP) channel pore inwardly, and the SUR1 protein that surrounds it forming the outside part of the channel were encoded by ABCC8 and KCNJ11 genes, respectively. Recent studies reported that the single nucleotide polymorphisms (SNPs) established in these genes are associated with defects in insulin secretion and type 2 diabetes mellitus (T2DM). We aimed to investigate the allele profiles and the risk alleles of the ABCC8 and KCNJ11 genes and to highlight the associations with the disease in patients in Konya region of Turkey where T2DM is common. METHODS In this study, 169 patients with T2DM and 119 healthy controls were included. A total of 29 SNPs in ABCC8 and KCNJ11 genes were screened by PCR-SSCP technique and sequenced. Biochemical parameters and genotype-phenotype relationships were analyzed using variance analysis. RESULTS R1273R silent substitution in exon 31 and 16/-3t→c substitution in noncoding region of exon 16 of ABCC8 gene showed a significant association (OR 4.8 [95% CI 2.41-9.77], p <0.001 and OR 3.5 [95% CI 1.64-7.40], p <0.001 under dominant and recessive models, respectively). We detected a significant association between E/K heterozygote genotype and reduced plasma insulin level in patients with T2DM (p <0.05). CONCLUSIONS ABCC8 exons 16 and 31 variants increase susceptibility to T2DM and KCNJ11 E23K decreases insulin secretion in a Turkish population.

Expression profile and polymorphisms of actin genes in protoscoleces of Echinococcus granulosus from sheep in central Turkey

The expression levels and polymorphisms of two actin genes, EgactI and EgactII, were investigated in the protoscoleces of Echinococcus granulosus isolated from sheep in the central region of Turkey. Only the EgactII gene was found to be expressed at detectable levels by protoscoleces in the present study. PCR-RFLP analysis and following sequence analysis revealed that a partial EgactI gene is more polymorphic than a partial EgactII gene. And, three alleles for EgactI gene were identified. In all samples, including three alleles, there were nucleotide substitutions at six positions of the partial EgactI gene, and were distinct from the reference sequence from GenBank(TM) database. These differences are referred to as the Anatolian haplotype.

Micronucleus frequency in acquired middle ear cholesteatoma

Objective—To determine the micronucleus (MN) frequency of acquired cholesteatoma tissue using an MN assay. Material and Methods—Eighteen patients were diagnosed as having chronic otitis media with acquired cholesteatoma and were divided into primary and secondary acquired cholesteatoma groups. Cholesteatoma tissue and normal tissue specimens from the external ear canal skin were taken from the patients during surgical operations. MN frequencies of cholesteatoma and control samples were determined according to standard criteria. Results—The MN frequencies of the cholesteatoma and control tissues were 0.54%±0.31% and 0.24%±0.11%, respectively (p<0.01). MN frequencies for the primary and secondary acquired cholesteatoma groups were 0.63%±0.36% and 0.46%±0.26%, respectively (p>0.05). MN frequencies in cholesteatoma patients without and with complications were 0.42%±0.19% and 0.85%±0.37%, respectively (p<0.05). Conclusion—MN frequencies were found to be increased in cholesteatoma tissues when compared with external ear canal skin. The MN frequency in five cases with complications was higher than in cases without complications. These results indicate that there could be associations between MN frequency and acquired cholesteatoma and between MN frequency and complications.