Structure-Activity Relationship of Methyl 4-Aminobenzoate Derivatives as Being Drug Candidate Targeting Glutathione Related Enzymes: in Vitro and in Silico Approaches

A thiol compound, glutathione, is essential for healthy cell defence against xenobiotics and oxidative stress. Glutathione reductase (GR) and glutathione S-transferase (GST) are two glutathione-related enzymes that function in the antioxidant and the detoxification systems. In this study, potential inhibitory effects of methyl 4-aminobenzoate derivatives on GR and GST were examined in vitro. GR and GST were isolated from human erythrocytes with 7.63 EU/mg protein and 5.66 EU/mg protein specific activity, respectively. It was found that compound 1 (methyl 4-amino-3-bromo-5-fluorobenzoate with K_i value of 0.325±0.012 μM) and compound 5 (methyl 4-amino-2-nitrobenzoate with K_i value of 92.41±22.26 μM) inhibited GR and GST stronger than other derivatives. Furthermore, a computer-aided method was used to predict the binding affinities of derivatives, ADME characteristics, and toxicities. Derivatives 4 (methyl 4-amino-2-bromobenzoate) and 6 (methyl 4-amino-2-chlorobenzoate) were estimated to have the lowest binding energies into GR and GST receptors, respectively according to results of in silico studies.     

Paraoxonase and arylesterase levels in autoimmune thyroid diseases

Objective: The aim of this study was to evaluate serum paraoxonase-1 (PON1) activity and its association with oxidative stress in autoimmune thyroid disease (AITD).

Methods: A total of 50 patients with AITD, including 25 with Hashimoto's thyroiditis and 25 with Graves’ disease were enrolled. The control group comprised 27 healthy subjects. Blood samples were obtained in the euthyroid period and 3 months after initiation of medical treatment. Serum samples from patients with AITD and the healthy control group were analyzed for basal PON1, salt-stimulated PON1, and arylesterase (ARE) activities, along with lipid hydroperoxide (LOOH) and total free sulfhydryl (–SH) levels.

Results: Serum PON1 activities and –SH levels were significantly lower (P?<?0.001, for each), whereas LOOH levels were significantly higher (P?<?0.001, for each) in patients with AITD, compared to the control group. We observed no significant differences in ARE levels between the patient and healthy control groups (P?>?0.05). PON1 activity was positively correlated with –SH (r?=?0.522, P?<?0.001) and negatively correlated with LOOH (r?=??0.487, P?<?0.001). PON1 phenotype distribution of the subjects was not significantly different among the three groups (P?=?0.961).

Conclusions: Serum PON1 activity is decreased in patients with AITD, and correlated positively with –SH, a well-known antioxidant, and negatively with LOOH, an index of lipid oxidation.     

The relationship between the presence of ADHD and certain candidate gene polymorphisms in a Turkish sample

Due to the high heritability of attention-deficit hyperactivity disorder (ADHD), parents of children with ADHD appear to represent a good sample group for investigating the genetics of the disorder. The aim of this study was to investigate the association between ADHD and six polymorphisms in five candidate genes [5-HT2A (rs6311), NET1 (rs2242447), COMT (rs4818), NTF3 (rs6332), SNAP-25 (rs3746544) and (rs1051312)]. We included 228 parents of children diagnosed with ADHD and 109 healthy parents as the control group. The polymorphisms were genotyped using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) assays and analyzed using the chi-square test and the multinomial logit model. SNAP-25 (rs3746544) polymorphism was associated with loading for ADHD, while 5-HT2A (rs6311) and NET1 (rs2242447) polymorphisms were associated with ADHD. On the other hand, there was no significant association between the SNAP-25 (rs1051312), NTF3 (rs6332), or COMT (rs4818) gene polymorphisms and ADHD.     

The Effect of Chronic Long-Term Intermittent Hypobaric Hypoxia on Bone Mineral Density in Rats: Role of Nitric Oxide

Intermittent hypoxia is the most common pattern of hypoxic exposure in humans. The effect of chronic long-term intermittent hypobaric hypoxia (CLTIHH) on bone metabolism is not investigated. We examined the effect of CLTIHH on bone metabolism and the role of nitric oxide (NO) in this process. The rats were divided into three groups in this study. The animals in groups I and II have been exposed to CLTIHH. The animals in group II were also treated with nitric oxide synthase inhibitor NG-nitro-l-arginine methyl ester. To obtain CLTIHH, rats were placed in a hypobaric chamber (430 mm Hg; 5 h/day, 5 days/week, 5 weeks). The group III (control) rats breathed room air in the same environment. At the begining of the experiments, bone mineral density (BMD) of the animals were measured, and blood samples were collected from the tail vein. After the 5-week CLTIHH period, the same measurements were repeated. Parathyroid hormone, calcium, phosphate, bone alkaline phosphatase (b-ALP), NO, interleukin 1 beta, interleukin 6, and tumor necrosis factor alpha levels were determined. The cytokines, NO levels, and BMD in CLTIHH-induced rats were higher compared with baseline and control values. The cytokines, b-ALP, and BMD increased while NO levels decreased in the group II compared with baseline values. BMD values of group II were lower than group I but higher than control group. Our results suggested that CLTIHH has positive effects on bone density. Intermittent hypoxia protocols may be developed for treatment and prevention of osteopenia and osteoporosis.     

Length–length and length–weight relationships for four endemic Cyprinid species in Küçük Menderes River Basin,Turkey

Length–length and length–weight relationships were studied for four endemic Cyprinid species from the Küçük Menderes River Basin located in the Western Anatolian region of Turkey. Fish were sampled from Tahtal? and Beyda?? reservoirs, Bulgurca, ?a?al and Azmak streams during 2013–2014, using multimesh gillnets in the reservoirs and by electrofishing in the streams. First records of length–weight relationships for Barbus pergamonensis Karaman, 1971, Squalius kosswigi (Karaman, 1972) and Petroleuciscus smyrnaeus (Boulenger, 1896) are reported in addition to three new maximum total lengths for Chondrostoma holmwoodii (Boulenger, 1896), Squalius kosswigi (Karaman, 1972) and Petroleuciscus smyrnaeus (Boulenger, 1896).     

Kinetic and docking studies of cytosolic/tumor-associated carbonic anhydrase isozymes I,II and IX with some hydroxylic compounds

A series of hydroxylic compounds (1–10, NK-154 and NK-168) have been assayed for the inhibition of three physiologically relevant carbonic anhydrase isozymes, the cytosolic isozymes I, II and tumor-associated isozyme IX. The investigated compounds showed inhibition constants in the range of 0.068–4003, 0.012–9.9 and 0.025–115?μm at the hCA I, hCA II and hCA IX enzymes, respectively. In order to investigate the binding mechanisms of these inhibitors, in silico studies were also applied. Molecular docking scores of the studied compounds are calculated using scoring algorithms, namely Glide/induced fit docking. The inhibitory potencies of the novel compounds were analyzed at the human isoforms hCA I, hCA II and hCA IX as targets and the K_I values were calculated.     

Identification of promoters bound by c-Jun/ATF2 during rapid large-scale gene activation following genotoxic stress

The NH2-terminal Jun kinases (JNKs) function in diverse roles through phosphorylation and activation of AP-1 components including ATF2 and c-Jun. However, the genes that mediate these processes are poorly understood. A model phenotype characterized by rapid activation of Jun kinase and enhanced DNA repair following cisplatin treatment was examined using chromatin immunoprecipitation with antibodies against ATF2 and c-Jun or their phosphorylated forms and hybridization to promoter arrays. Following genotoxic stress, we identified 269 genes whose promoters are bound upon phosphorylation of ATF2 and c-Jun. Binding did not occur following treatment with transplatin or the JNK inhibitor SP600125 or JNK-specific siRNA. Of 89 known DNA repair genes represented on the array, 23 are specifically activated by cisplatin treatment within 3-6 hr. Thus, the genotoxic stress response occurs at least partly via activation of ATF2 and c-Jun, leading to large-scale coordinate gene expression dominated by genes of DNA repair.     

Distinctly different gene structure of KLK4/KLK-L1/prostase/ARM1 compared with other members of the kallikrein family: intracellular localization, alternative cDNA forms, and Regulation by multiple hormones

The tissue kallikreins (KLKs) form a family of serine proteases that are involved in processing of polypeptide precursors and have important roles in a variety of physiologic and pathological processes. Common features of all tissue kallikrein genes identified to date in various species include a similar genomic organization of five exons, a conserved triad of amino acids for serine protease catalytic activity, and a signal peptide sequence encoded in the first exon. Here, we show that KLK4/KLK-L1/prostase/ARM1 (hereafter called KLK4) is the first significantly divergent member of the kallikrein family. The exon predicted to code for a signal peptide is absent in KLK4, which is likely to affect the function of the encoded protein. Green fluorescent protein (GFP)-tagged KLK4 has a distinct perinuclear localization, suggesting that its primary function is inside the cell, in contrast to the other tissue kallikreins characterized so far that have major extracellular functions. There are at least two differentially spliced, truncated variants of KLK4 that are either exclusively or predominantly localized to the nucleus when labeled with GFP. Furthermore, KLK4 expression is regulated by multiple hormones in prostate cancer cells and is deregulated in the androgen-independent phase of prostate cancer. These findings demonstrate that KLK4 is a unique member of the kallikrein family that may have a role in the progression of prostate cancer.