Browsing by Author "Zeybek U."

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A study of short- and long-term mRNA levels of the retn, iapp, and Drd5 genes in obese mice induced with high-fat diet
(2018-07-01) Timirci-Kahraman O.; Yilmaz U.; Yilmaz N.; Cevik A.; Horozoglu C.; Celik F.; Oguz Gokce M.; Ergen A.; Melekoglu A.; Zeybek U.
Background/Aim: Adipocyte gene expression is altered in obese individuals through multiple metabolic and biochemical pathways. In this study, we aimed to examine the expression of resistin (Retn), amylin (Iapp), and dopamine receptor domain 5 (Drd5) genes previously suggested to contribute to the pathogenesis of obesity, albeit controversially. We also aimed to determine the effects on short and long-term mRNA levels of these genes in obese mice, induced with high-fat diet (HFD). Materials and Methods: Two obesity models were created in our study: group T1 (20 mice) was fed with HFD (60% fat) for 3 months, and group T2 (20 mice) was fed with HFD (60% fat) for 6 months. The control group T0 (20 mice) was fed with a diet of 10% kcal fat supplement for 6 months. At the end of the experiment, their adipose tissues were dissected surgically. Tissue samples of each group were pooled for RNA isolation, cDNA synthesis was carried out and the mRNA levels were examined by quantitative real-time polymerase chain reaction. Serum resistin levels were measured using multiplex bead (luminex) technology for validation. Results: In T2 mice, the mRNA expression of Retn showed a moderate up-regulation (fold change=8.32; p=0.0019) in the adipose tissues. Iapp expression was also significantly up-regulated (fold change=9.78; p=0.012). Moreover, a 6.36-fold up-regulation for Drd5 was observed in the adipose tissues of T2 mice (p<0.001). At the same time, serum levels of resistin were found to be high in T1 and T2 mice compared to the control group (p<0.001 and p=0.024, respectively). Conclusion: Our study demonstrated that the mRNA levels of the genetic markers considered to play a role in adipogenesis were different in short- and long-term obesity models formed in C57BL/6J mice using HFD.
Individual and combined effects of CTLA4-CD28 variants and oxidant-antioxidant status on the development of colorectal cancer
(2015-10-01) Kucukhuseyin O.; Turan S.; Yanar K.; Arikan S.; Duzkoylu Y.; Aydin S.; Cakatay U.; Mezani B.; Farooqi A.A.; Aydinoʇlu Isitmangil G.; Kiran B.; Cacina C.; Nurdan Yenilmez E.; Ergen A.; Zeybek U.; Yaylim I.
Background: Colorectal cancer (CRC) is the third most frequent cancer worldwide. Research has revealed the contributions of the immune system and anti-inflammatory pathways in the development of cancer. The balance between cluster of differentiation 28 (CD28) and cytotoxic Tlymphocyte- associated protein 4 (CTLA4) signaling is important for the regulation of immune responses. The oxidant-antioxidant balance by sustaining redox control via several defense mechanisms is also an important factor for the progression of cancer. The aim of the present study was to determine the distribution of CTLA4/CD28 variants and oxidant-antioxidant status in patients with CRC. Materials and Methods: This study enrolled 80 patients with CRC and 115 healthy controls. We used a spectrophotometric assay to detect the levels of lipid peroxidation products malon dialdehyde (MDA) and lipid hydroperoxide (LHP), and measured the concentration of protein damage products, advanced oxidation protein products (AOPP) and protein carbonyl (PCO). Additionally, antioxidant levels were detected by measuring copper, zinc, superoxide dismutase (Zn-Cu SOD) and total thiol (T-SH) levels, and advanced glycation end-products (AGEs). The CTLA4 -318C>T, CTLA4 49A>G and CD28C>T genotypes were determined by using restriction enzymes. Results: AOPP and PCO levels were increased in patients with CRC as well as those of LHP, MDA and AGE, while the levels of antioxidants such as Cu-Zn SOD and T-SH were lower. Lower serum levels of CTLA4 and higher serum levels of CD28 were detected in patients and, an association of the CTLA4 -318C/T polymorphism was found in patients with CRC. Conclusion: Our oxidative stress was increased in patients with CRC, suggesting the contribution of this disturbed oxidative status to serum CTLA4 and CD28 levels, and to the pathogenesis of CRC.