Ozgur Aldemir

Investigation of key miRNAs and target genes in bladder cancer using miRNA profiling and bioinformatic tools

Despite the association of several miRNAs with bladder cancer, little is known about the miRNAs’ regulatory networks. In this study, we aimed to construct potential networks of bladder-cancer-related miRNAs and their known target genes using miRNA expression profiling and bioinformatics tools and to investigate potential key molecules that might play roles in bladder cancer regulatory networks. Global miRNA expression profiles were obtained using microarray followed by RT-qPCR validation using two randomly selected miRNAs. Known targets of deregulated miRNAs were utilized using DIANA-TarBase database v6.0. The incorporation of deregulated miRNAs and target genes into KEGG pathways were utilized using DIANA-mirPath software. To construct potential miRNA regulatory networks, the overlapping parts of three selected KEGG pathways were visualized by Cytoscape software. We finally gained 19 deregulated miRNAs, including 5 ups- and 14 down regulated in 27 bladder-cancer tissue samples and 8 normal urothelial tissue samples. The enrichment results of deregulated miRNAs and known target genes showed that most pathways were related to cancer or cell signaling pathways. We determined the hub CDK6, BCL2, E2F3, PTEN, MYC, RB, and ERBB3 target genes and hub hsa-let-7c, hsa-miR-195-5p, hsa-miR-141-3p, hsa-miR-26a-5p, hsa-miR-23b-3p, and hsa-miR-125b-5p miRNAs of the constructed networks. These findings provide new insights into the bladder cancer regulatory networks and give us a hypothesis that hsa-let-7c, hsa-miR-195-5p, and hsa-miR-125b-5p, along with CDK4 and CDK6 genes might exist in the same bladder cancer pathway. Particularly, hub miRNAs and genes might be potential biomarkers for bladder cancer clinics.

The spectrum of β-thalassemia mutations in Hatay, Turkey: reporting three new mutations.

Abstract β-Thalassemia (β-thal) is an important health problem in Hatay, Southern Turkey, because of its high carrier frequency and the frequency of consanguinity. The aim of this study was to reveal the spectrum of β-thal mutations and to provide a foundation for prenatal genetic testing that will be a part of an effective prevention program for β-thal disease in Hatay. We determined the spectrum of β-thal mutations in 93 unrelated affected patients. Using a direct sequencing method, we identified a large number of β-thal mutations. We found different results from other parts of Turkey. A total of 16 different β-thal mutations were characterized in the parents. The most common mutations were: IVS-I-110 (G>A), IVS-I-6 (T>C), IVS-I-1 (G>A), frameshift codon (FSC) 8 (–AA), codon 39 (C>T) and IVS-II-745 (C>G). Since our region has seen many Syrian and Iraqi immigrants, we report that the prevalence of the thalassemia traits are different from other regions of Turkey. Our study demonstrates the spectrum of β-thal mutations in the Hatay region, and that there was great molecular heterogeneity.

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism in psoriasis in southern Turkey.

Background Psoriasis is a multigenic and multifactorial dermatological disease linked to cardiovascular diseases. Increased levels of homocysteine in patients with psoriasis have been demonstrated in many studies. The most frequently investigated genetic defect that plays a role in homocysteine metabolism is single point substitution (C to T) located on the 677th nucleotide of the methylenetetrahydrofolate reductase gene (MTHFR). Objective In this study, we aimed to investigate methylenetetrahydrofolate C677T polymorphism in psoriasis patients in Turkey. Methods The study included 96 patients with psoriasis and 77 controls from southern Turkey. Methylenetetrahydrofolate C677T polymorphism was analysed using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism methods. Results In the psoriasis group, 34 CC (35.4%), 46 CT (47.9%) and 16 TT (16.7%) genotypes were found, respectively; while in the control group, the figures were 39 (50.6%), 35 (45.5%), 3 (3.9%). Homozygote and heterozygote T alleles of methylenetetrahydrofolate C677T polymorphism were significantly higher in the psoriasis than in the control group (p=0.013). Conclusion We firstly found a correlation between methylenetetrahydrofolate C677T polymorphism and psoriasis among the southern Turkish population.

The association between methylation levels of targeted genes and albuminuria in patients with early diabetic kidney disease

Abstract Objective: The incidence of diabetes and its complications are greatly increasing world-wide. Diabeticnephropathy (DN) is the main cause of end-stage renal disease and is associated with high morbidity and mortality. It is important to predict patients with high risk for DN in the early stage. We selected the genes which have an important role on diabetic kidney disease. We aimed to investigate the association between DNA methylation levels of targeted genes and albuminuria in patients with early DN. Methods: We collected the clinical data of patients with type 2 diabetes mellitus. We measured spot urine albumin creatinine ratio to calculate albuminuria level. We divided patients into two groups based on albumin excretion as patients with (n = 69) and without DN (n = 27). We performed methylation profiling after bisulfite conversion by pyrosequencing method. The mean value of percent methylation level of each gene was calculated. Results: We compared targeted genes (TIMP-2, AKR1B1, MMP-2, MMP-9, MYL9, SCL2A4, SCL2A1, SCL4A3) methylation levels and albuminuria. We found significant negative correlation between TIMP-2 and AKR1B1 gene methylation levels and albuminuria levels. Conclusions: The present study provided evidence that hypomethylation of TIMP-2 and AKR1B1 genes can be associated with albuminuria in patients with early DN. We may speculate that the hypomethylation of TIMP-2 and AKR1B1 genes may be an early surrogate marker of DN.

Pendred Sendromlu Türk Ailede SCL26A4 Geninde Yeni Mutasyon

Aim: This study aimed to investigate the molecular testing of congenital hearing loss by using next generation sequencing technology. Pendred syndrome (PS) is described by severe bilateral sensorineural hearing loss with goiter. The mutations of SCL26A4 gene can cause PS. Material and Method: We evaluated the feasibility of target-enrichment and massive parallel sequencing technologies to interrogate all mutations of genes (GJB2, GJB3, GJB6, SLC26A4 and for the mitochondrial mutation A1555G) implicated in NSHL, we performed molecular analyses of 14 NSHL families and patients by using Miseq system (Illumina Inc.). Next-Generation sequencing (NGS) technologies provide specificity, sensitivity and reproducibility at levels sufficient to perform genetic diagnosis of hearing loss. Results: We found two different mutations in SCL26A4 gene such as F354S and I588T in both consanguineous families as diagnosed with Pendred syndrome and we reported a novel mutation in SCL26A4 gene. We found no mutation in GJB2, GJB3, GJB6 gene and A1555G mtDNA in this study. Conclusion: These results highlight the benefits using targeted gene panels with NGS technologies in the molecular analysis of nonsyndromic, congenital hearing loss patients. This study assessed the frequency of deafness genes in Turkish children with congenital hearing loss who had been treated with cochlear implantation, and we found a novel mutation (I588T) in SLC26A4 gene. Key Words: Pendred syndrome, Congenital Hearing Loss, Next-Generation sequencing