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Plasma levels of glial cell line-derived neurotrophic factor (GDNF), a pivotal regulator of differentiation and survival of dopaminergic neurons, are reportedly decreased in schizophrenia. To explore the involvement of GDNF in the pathogenesis of the disease, a case–control association analysis was performed between five non-coding single nucleotide polymorphisms (SNP) across the GDNF gene and schizophrenia. Of them, the 'G' allele of the rs11111 SNP located in the 3′ untranslated region (3′-UTR) of the gene was found to associate with schizophrenia. In silico analysis revealed that the rs11111 'G' allele might create binding sites for three microRNA (miRNA) species. To explore the significance of this polymorphism, transient co-transfection assays were performed in human embryonic kidney 293T (HEK293T) cells with a luciferase reporter construct harboring either the 'A' or 'G' allele of the 3′-UTR of GDNF in combination with the hsa-miR-1185-1-3p pre-miRNA. It was demonstrated that in the presence of the rs11111 'G' (but not the 'A') allele, hsa-miR-1185-2-3p repressed luciferase activity in a dose-dependent manner. Deletion of the miRNA binding site or its substitution with the complementary sequence abrogated the modulatory effect. Our results imply that the rs11111 'G' allele occurring more frequently in patients with schizophrenia might downregulate GDNF expression in a miRNA-dependent fashion. [ABSTRACT FROM AUTHOR]

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Background: Type 2 diabetes (T2DM) and colorectal cancer (CRC) are both known to modulate gene expression patterns in peripheral blood leukocytes (PBLs)., Objective: As T2DM has been shown to increase the incidence of CRC, we were prompted to check whether diabetes affects mRNA signatures in PBLs isolated from CRC patients., Methods: Twenty-two patients were recruited to the study and classified into four cohorts (healthy controls; T2DM; CRC; CRC and T2DM). Relative expression levels of 573 cell signaling gene transcripts were determined by reverse transcription real-time PCR assays run on low-density OpenArray platforms. Enrichment analysis was performed with the g:GOSt profiling tool to order differentially expressed genes into functional pathways., Results: 49 genes were found to be significantly up- or downregulated in tumorous diabetic individuals as compared to tumor-free diabetic controls, while 11 transcripts were differentially regulated in patients with CRC versus healthy, tumor-free and nondiabetic controls. Importantly, these gene sets were completely distinct, implying that diabetes exerts a profound influence on the transcription of signaling genes in CRC. The top 5 genes showing the most significant expression differences in both contexts were PCK2, MAPK9, CCND1, HMBS, TLR3 (p≤0.0040) and CREBBP, PPIA, NFKBIL1, MDM2 and SELPLG (p≤0.0121), respectively. Functional analysis revealed that most significantly affected pathways were cytokine, interleukin and PI3K/Akt/mTOR signaling cascades as well as mitotic regulation., Conclusion: We propose that differentially expressed genes listed above might be potential biomarkers of CRC and should be studied further on larger patient groups. Diabetes might promote colorectal carcinogenesis by impairing signaling pathways in PBLs., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Introduction and aim: Earlier results in the literature suggest that overweight subjects show weaker performance in executive function tasks as compared to normal weight people. Dopaminergic system is strongly linked to executive functions, body mass regulation and ingestion. The aim of the present study was to examine the possible relationship between DRD4 VNTR 7-repeat allele, body mass index and Stroop performance in a healthy adult population, and to draw psychogenetic conclusions. Method: 152 subjects without diabetic or psychiatric history participated in the study. Along with non-invasive DNA sampling, demographic, weight and height data were collected. The participants also solved the computerized Stroop task. 11 subjects belonged to the underweight (mean body mass index = 17.9 kg/m 2 ), 98 subjects to the normal (mean body mass index = 21.8 kg/m 2 ), and 43 subjects to the overweight (mean body mass index = 28.9 kg/m 2 ) category. After grouping participants according to their body mass index and DRD4 VNTR genotype, we compared their mean performance to investigate the possible psychogenetic associations. Results: Body mass index and stimuli type showed significant interaction on error number (p = 0.045): subjects with normal body mass index made significantly less error as compared to under- and overweight subjects in incongruent trials. The 7-repeat allele carriers made tendentiously more errors than non-carriers. Normal weight people made less error - independently from their genotype -, while subjects with either low or high BMI carrying the 7-repeat allele made more errors compared to non-carriers. Conclusion: Under- and overweight subjects perform weaker where inhibition is necessary in the task. This may reflect their reactions to food-related situations. Orv Hetil. 2019; 160(39): 1554-1562.

Although the Human Genome Project discovered the sequence of the human genetic information 15 years ago, genetic background of the diseases - primarily that of complex disorders - is still not known. The sum of the not yet discovered inherited risk factors is termed the missing heritability; the identification of these genetic components is, however, essential, as it is the base of the understanding of the molecular pathomechanism of diseases. It is not only of theoretical importance: this knowledge can be used in the clinical practice, as it offers the possibility of improvement of diagnostics, prevention as well as targeted and individualized therapy. Application of novel and more efficient molecular biological tools contribute to the discovery of unknown genetic factors, the complete goal can only be achieved, however, by re-conceptualization of several clinical and genetic points. Our knowledge was established by genome-wide studies, however, further knowledge must be acquired according to the following points: (1) genotype and association analysis of repeat variations (VNTRs and CNVs) besides SNPs, (2) investigation of gene-gene and gene-environment interactions, (3) epigenetic studies, (4) assessing the biological function of polymorphisms, (5) application of biologically relevant diagnostic categories and endophenotypes. Although it is only 1.2% of the whole genome that codes for proteins, however, as much as 90% is transcribed to RNA, consequently it can be hypothesized that gene expression analyses might offer promising starting points for further studies, as they can shed light on the molecular processes that contribute to the development of diseases. Orv Hetil. 2018; 159(31): 1254-1261.