Associations of free, bioavailable and total 25-hydroxyvitamin D with neonatal birth anthropometry and calcium homoeostasis in mother-child pairs in a sunny Mediterranean region

Sufficient vitamin D status is crucial for successful pregnancy and fetal development. The assessment of 25-hydroxyvitamin D (25(OH)D) concentrations is commonly used to evaluate vitamin D status. Our objective was to examine the interrelated biodynamics of maternal and neonatal total, free and bioavailable 25(OH)D in maternal-neonatal dyads at birth and their associations with homeostasis and neonatal birth anthropometry. We analysed a cohort of seventy full-term mother-child pairs. We found positive associations between all neonatal measures of vitamin D status. Maternal forms exhibited a similar pattern of association, except for the bioavailable maternal form. In multivariate analysis, both total and free maternal 25(OH)D concentrations were correlated with all neonatal forms (neonatal total 25(OH)D: 1·29 (95 % CI, 1·12, 1·46) for maternal total 25(OH)D, 10·89 (8·16, 13·63) for maternal free 25(OH)D), (neonatal free 25(OH)D: 0·15 for maternal total 25(OH)D, 1·28 (95 % CI, 0·89, 1·68) for maternal free 25(OH)D) and (0·13 (95 % CI, 0·10, 0·16), 1·06 (95 % CI, 0·68, 1·43) for maternal free 25(OH)D), respectively, with the exclusion of the bioavailable maternal form. We observed no significant interactions within or between groups regarding maternal and neonatal vitamin D parameters and maternal calcium and parathyroid hormone concentrations, and neonatal birth anthropometry. Our study indicates that bioavailable maternal and neonatal 25(OH)D have no significant effects on vitamin D equilibrium, Ca homeostasis and neonatal anthropometry at birth. However, we observed an interaction between maternal and neonatal total and free 25(OH)D concentrations at the maternal-neonatal interface, with no associations observed with other calciotropic or anthropometric outcomes.

miRNAs as predictive biomarkers of response to treatment in pediatric patients with acute lymphoblastic leukemia

MicroRNAs (miRNAs/miRs) are promising prognostic biomarkers in pediatric acute lymphoblastic leukemia (ALL). The present study aimed to identify miRNAs that could serve as prognostic biomarkers or as novel therapeutic targets in ALL. The expression levels of 84 miRNAs were assessed in the bone marrow aspirates of 10 pediatric patients with newly diagnosed ALL at diagnosis and on day 33 of induction of the ALL Intercontinental Berlin-Frankfurt-Münster 2009 protocol, and associations with established prognostic factors were evaluated. The levels at diagnosis of 25 miRNAs were associated with ≥2 prognostic factors. Higher expression levels of let-7c-5p, miR-106b-5p, miR-26a-5p, miR-155-5p, miR-191-5p, miR-30b-5p and miR-31-5p were significantly associated with a good prednisone response. The expression levels of miR-125b-5p, miR-150-5p and miR-99a-5p were significantly higher in standard- or intermediate-risk patients compared with those in high-risk patients (P=0.017, P=0.033 and P=0.017, respectively), as well as in those with a complete response at the end of induction (P=0.044 for all three miRNAs). The change in expression levels between diagnosis and the end of induction differed significantly between risk groups for three miRNAs: miR-206, miR-210 and miR-99a (P=0.033, P=0.047 and P=0.008, respectively), with the post induction levels of miR-206 increased in high-risk patients, whilst miR-210 and miR-99a levels were increased in intermediate/standard risk patients. Therefore, miRNAs that could be integrated into the risk stratification of pediatric ALL after further evaluation in larger patient cohorts were identified.

Therapeutic Potentials of Reducing Liver Fat in Non-Alcoholic Fatty Liver Disease: Close Association with Type 2 Diabetes

Nonalcoholic fatty liver disease (NAFLD), the most widespread chronic liver disease worldwide, confers a significant burden on health systems and leads to increased mortality and morbidity through several extrahepatic complications. NAFLD comprises a broad spectrum of liver-related disorders, including steatosis, cirrhosis, and hepatocellular carcinoma. It affects almost 30% of adults in the general population and up to 70% of people with type 2 diabetes (T2DM), sharing common pathogenetic pathways with the latter. In addition, NAFLD is closely related to obesity, which acts in synergy with other predisposing conditions, including alcohol consumption, provoking progressive and insidious liver damage. Among the most potent risk factors for accelerating the progression of NAFLD to fibrosis or cirrhosis, diabetes stands out. Despite the rapid rise in NAFLD rates, identifying the optimal treatment remains a challenge. Interestingly, NAFLD amelioration or remission appears to be associated with a lower risk of T2DM, indicating that liver-centric therapies could reduce the risk of developing T2DM and vice versa. Consequently, assessing NAFLD requires a multidisciplinary approach to identify and manage this multisystemic clinical entity early. With the continuously emerging new evidence, innovative therapeutic strategies are being developed for the treatment of NAFLD, prioritizing a combination of lifestyle changes and glucose-lowering medications. Based on recent evidence, this review scrutinizes all practical and sustainable interventions to achieve a resolution of NAFLD through a multimodal approach.

Dysregulation of Plasma miR-146a and miR-155 Expression Profile in Mycosis Fungoides Is Associated with rs2910164 and rs767649 Polymorphisms

Diagnosis of Mycosis Fungoides (MF) may be challenging, due to its polymorphic nature. The use of miRNAs as biomarkers to assist in diagnosis has been investigated, mainly in skin lesion biopsies. The purpose of this study is to evaluate the plasma levels of miR-146a and miR-155 in MF patients and to investigate their association with SNPs of their genes. Plasma miRNAs were quantified by RT-qPCR. Genomic DNA was used for SNPs’ genotyping by Sanger sequencing. Plasma levels of miR-146a and miR-155 were significantly higher in patients vs. controls, in early MF patients vs. controls, and in advanced vs. early MF patients. Both miRNAs’ levels were significantly higher in stage IIB vs. early-stage patients. miR-155 plasma levels were significantly higher in patients with skin tumors or erythroderma. CC genotype (rs2910164 C>G) was significantly more frequent in healthy controls and associated with lower MF risk and lower miR-146a levels. The AA genotype (rs767649 T>A) was significantly more frequent in patients and correlated with increased MF risk and increased miR-155 levels. The combination of GG+AA was only detected in patients and was correlated with higher MF susceptibility. Increased mir-146a and mir-155 plasma levels in MF is an important finding to establish putative noninvasive biomarkers. The presence of SNPs is closely associated with miRs’ expression, and possibly with disease susceptibility.

DNA hypermethylation of PTPN22 gene promoter in children and adolescents with Hashimoto thyroiditis

PURPOSE

Protein tyrosine phosphatase non-receptor type 22 (PTPN22) is an inhibitor of T-cell activation, regulating intracellular signal transduction and thereby being implicated in the pathogenesis of autoimmune thyroid disease (AITD). The exact molecular mechanisms have not been fully elucidated. The aim of the present study was to quantitate DNA methylation within the PTPN22 gene promoter in children and adolescents with AITD and healthy controls.

METHODS

60 Patients with Hashimoto thyroiditis (HT), 25 patients with HT and type 1 diabetes (HT + T1D), 9 patients with Graves' disease (GD) and 55 healthy controls without any individual or family history of autoimmune disease were enrolled. Whole blood DNA extraction, DNA modification using sodium bisulfate and quantification of DNA methylation in the PTPN22 gene promoter, based on melting curve analysis of the selected DNA fragment using a Real-Time PCR assay, were implemented.

RESULTS

DNA methylation in the PTPN22 gene promoter was found to be significantly higher in HT patients (39.9 ± 3.1%) in comparison with other study groups (20.3 ± 2.4% for HT + T1D, 32.6 ± 7.8% for GD, 27.1 ± 2.4% for controls, p < 0.001). PTPN22 gene promoter DNA methylation was also associated marginally with thyroid autoimmunity in general (p = 0.059), as well as considerably with thyroid volume (p = 0.004) and the presence of goiter (p = 0.001) but not thyroid function tests.

CONCLUSIONS

This study demonstrates for the first time that a relationship between autoimmune thyroiditis and PTPN22 gene promoter DNA methylation state is present, thus proposing another possible etiological association between thyroiditis and abnormalities of PTPN22 function. Further expression studies are required to confirm these findings.

Salivary diagnostics of the novel coronavirus SARS-CoV-2 (COVID-19)

Introduction

Laboratory testing for the SARS‐CoV‐2 virus and the consequent respiratory coronavirus disease 2019 (COVID‐19) is categorized into methods that detect the viral presence and methods that detect antibodies produced in the host as a response to infection. Methods that detect viral presence into the host excretions measure current infection by SARS‐CoV‐2, whereas the detection of human antibodies exploited against SARS‐CoV‐2 evaluates the past exposure to the virus.

Objective

This review provides a comprehensive overview for the use of saliva as a specimen for the detection of SARS‐CoV‐2, the methods for the salivary diagnostics utilized till very recently, and the arisen considerations for the diagnosis of COVID‐19 disease.

Conclusion

The major advantage of using saliva as a specimen for the detection of SARS‐CoV‐2 is that saliva collection is a non‐invasive method which produces no discomfort to the patient and permits the patients to utilize home self‐sampling techniques in order to protect health providers from the exposure to the pathogen. There is an urgent need to increase the active research for the detection of SARS‐CoV‐2 in the saliva because the non‐invasive salivary diagnostics may provide a reliable and cost‐effective method suitable for the fast and early detection of COVID‐19 infection.

Towards analyzing the potential of exosomes to deliver microRNA therapeutics

Exosome selectivity mechanisms underlying exosome-target cell interactions and the specific traits affecting their capability to communicate still remain unclear. Moreover, the capacity of exosomes to efficiently deliver their molecular cargos intracellularly needs precise investigation towards establishing functional exosome-based delivery platforms exploitable in the clinical practice. The current study focuses on: (a) exosome production from normal MRC-5 and Vero cells growing in culture, (b) physicochemical characterization by dynamic light scattering (DLS) and cryo-transmission electron microscopy; (c) cellular uptake studies of rhodamine-labeled exosomes in normal and cancer cells, providing to exosomes either "autologous" or "heterologous" cellular delivery environments; and (d) loading exogenous Alexa Fluor 488-labeled siRNA into exosomes for the assessment of their delivering capacity by immunofluorescence in a panel of recipient cells. The data obtained thus far indicate that MRC-5 and Vero exosomes, indeed exhibit an interesting delivering profile, as promising "bio-shuttles," being pharmacologically exploitable in the context of theranostic applications.

Insulin gene promoter methylation status in Greek children and adolescents with Type 1 Diabetes

The insulin (INS) gene is the one of the most important genes involved in the pathogenesis of Type 1 Diabetes (T1D) after the Major Histocompatibility Complex genes. Studies addressing the issue of hyper- or hypo-methylation status of the INS gene promoter have reported inconsistent results. The majority of studies showed hypomethylation; however a few studies have shown hypermethylation at specific cytosine-guanosine (CpG) sites in the promoter region of the INS gene. The aim of the present study was to analyze the methylation status of the promoter region of the INS gene in Greek children and adolescents with T1D. A total of 20 T1D participants (mean diabetes duration of 6.15±4.12 years) and 20 age- and sex-matched controls were enrolled in the present study. DNA was isolated from whole blood samples, modified using sodium bisulfite and analyzed using PCR and electrophoresis. DNA was then pooled with highly reactive supermagnetic beads at similar molar quantities, submitted for library construction and finally sequenced using next-generation sequencing. The methylation profile at 10 CpG sites around the transcription start site (TSS) of the INS promoter was analysed and expressed as the mean ± standard deviation. The overall mean methylation in patients with T1D did not differ compared with the healthy controls. There was a statistically significant difference between the two groups in hypermethylation at position -345 (P=0.02), while a trend (P=0.06) at position -102 was observed. According to the results of the present study, increased methylation in the INS gene promoter at specific CpG sites around the TSS were already present in childhood T1D. These data may possibly serve as a guide towards the identification of a methylation pattern for detection of development of T1D in genetically predisposed children.

Correlation of miR-146a-5p plasma levels and rs2910164 polymorphism with left ventricle outflow tract obstruction in hypertrophic cardiomyopathy

OBJECTIVE

Hypertrophic cardiomyopathy (HCM) is a genetic disease of the myocardium that is characterized by phenotypic variability among patients. miR-146a is a small non-coding RNA that is well known for its role in inflammation and myocardial hypertrophy. The aim of this study is to evaluate the role of miR-146a as a candidate genetic factor influencing HCM phenotype.

METHODS

In this study, 140 HCM patients and 112 control individuals were genotyped for the rs2910164 single nucleotide polymorphism (SNP) in the MIR146A gene; using this data, the correlation between different genotypes and clinical features of the disease were determined. Additionally, plasma levels of miR-146a-5p were determined in 50 HCM patients and 30 control individuals by using qPCR.

RESULTS

The incidence of GC and CC genotypes were significantly lower in HCM patients (odds ratio (OR) = 0.5 [0.3-0.8], p = 0.007). The GC/CC genotypes in the dominant genetic model positively correlated with the presence of left ventricle outflow tract (LVOT) obstruction (OR = 2.3 [1.2-4.7] and p = 0.018), a higher left ventricle mass index (118 ± 47 g/m² vs 92 ± 42 g/m² and p = 0.02), and increased left ventricle end-diastolic diameter (4.66 ± 0.64cm vs 4.39 ± 0.7cm and p = 0.026). Atrial fibrillation was significantly higher in patients homozygous for the C allele (OR = 10.6 [2-55], p = 0.003). Interestingly, the plasma levels of miR-146a-5p were significantly increased in HCM patients with LVOT obstruction.

CONCLUSION

Our findings indicate that the C allele of the rs2910164 SNP might be under negative selection in HCM patients. Additionally, plasma levels of miR-146a-5p and GC/CC genotypes are indicative of the obstructive phenotype in HCM patients.

DNA methylation analysis within the IL2RA gene promoter in youth with autoimmune thyroid disease

BACKGROUND

Alpha-subunit of the interleukin-2 receptor (IL2RA) is involved in the regulation of T-cell function and has been related to autoimmune thyroid disease (AITD). Although the exact mechanisms are not fully understood, promoter methylation might account for differences in gene expression. The aim of this study was to investigate whether there are differences in the percentage of DNA methylation within the IL2RA gene promoter in young patients with AITD.

MATERIALS AND METHODS

In a cross-sectional design, the presence of DNA methylation in the IL2RA gene promoter was quantified, by real-time PCR and melting curve analysis, in modified genomic DNA isolated from blood samples of a total of 149 children and adolescents with AITD, including patients with Hashimoto thyroiditis (ΗΤ) (n = 60), Graves' disease (GD) (n = 9), concurrent diagnosis of HT and type 1 diabetes (T1DM + HT) (n = 25), and healthy controls (n = 55).

RESULTS

The percentage of DNA methylation in the IL2RA gene promoter was significantly decreased in patients with GD (26.0 ± 4.2%) but not in those with HT (36.3 ± 1.4%) in comparison with controls (41.3 ± 1.5%).

CONCLUSIONS

The observed DNA hypomethylation in the IL2RA gene promoter in patients with GD might be related to its increased expression, thus contributing to the etiopathogenesis of GD in childhood and adolescence.

MeinteR: A framework to prioritize DNA methylation aberrations based on conformational and cis-regulatory element enrichment

DNA methylation studies have been reformed with the advent of single-base resolution arrays and bisulfite sequencing methods, enabling deeper investigation of methylation-mediated mechanisms. In addition to these advancements, numerous bioinformatics tools address important computational challenges, covering DNA methylation calling up to multi-modal interpretative analyses. However, contrary to the analytical frameworks that detect driver mutational signatures, the identification of putatively actionable epigenetic events remains an unmet need. The present work describes a novel computational framework, called MeinteR, that prioritizes critical DNA methylation events based on the following hypothesis: critical aberrations of DNA methylation more likely occur on a genomic substrate that is enriched in cis-acting regulatory elements with distinct structural characteristics, rather than in genomic “deserts”. In this context, the framework incorporates functional cis-elements, e.g. transcription factor binding sites, tentative splice sites, as well as conformational features, such as G-quadruplexes and palindromes, to identify critical epigenetic aberrations with potential implications on transcriptional regulation. The evaluation on multiple, public cancer datasets revealed significant associations between the highest-ranking loci with gene expression and known driver genes, enabling for the first time the computational identification of high impact epigenetic changes based on high-throughput DNA methylation data.

OPG/RANK/RANKL signaling axis in patients with type I diabetes: Associations with parathormone and vitamin D

BACKGROUND

Type 1 diabetes (T1D) has been associated with a higher fracture risk due to alterations in bone structure and metabolism. On the other hand, the important role of the RANKL/OPG/RANK signaling axis in bone physiology is well established. The aim of this study was to evaluate the levels of receptor activator of nuclear factor kappa-B ligand (RANKL), receptor activator of nuclear factor kappa-B (RANK) and plasma osteoprotegerin (OPG) levels, in T1D youngsters and to investigate factors that could influence the OPG/RANK/RANKL signaling axis such as 25-hydroxy vitamin D [25(OH) D], parathormone (PTH) and age.

METHODS

Serum RANKL, RANK, 25(OH) D, PTH levels and plasma OPG levels, were measured in 71 youngsters with T1D and 50 healthy controls matched for age and gender.

RESULTS

Plasma OPG levels were significantly lower (p = 0.025) in T1D patients compared to controls. Serum RANKL levels were significantly higher (p = 0.037), while no differences were observed in serum RANK levels (p = 0.946) between the two groups. Serum 25(OH) D levels found significantly decreased (p < 0.001) while serum PTH levels were significantly elevated (p < 0.001) in T1D patients than in controls.

CONCLUSIONS

Our results demonstrated that OPG and RANKL may be promising biomarkers for T1D patients. However, their circulating levels were associated with several factors including PTH, 25(OH) D and therefore, may represent an integrative biomarker for a variety of endocrine signaling disturbances observed in T1D.

Gene promoter methylation and cancer: An umbrella review

Gene promoter methylation is a common epigenetic event, taking place in the early phase of tumorigenesis, which has a great potential as a diagnostic and prognostic cancer biomarker. In this umbrella review, we provide an overview on the association between gene-promoter methylation of protein-coding genes and cancer risk based on currently available meta-analyses data on gene promoter methylation. We searched MEDLINE via PubMed and the Cochrane Database of Systematic Reviews for meta-analyses that examine the association between gene-promoter methylation and cancer, published until January 2019 in English. We used AMSTAR to assess the quality of the included studies and applied a set of pre-specified criteria to evaluate the magnitude of each association. We provide a comprehensive overview of 80 unique combinations between 22 different genes and 18 cancer outcomes, all of which indicated a positive association between promoter hypermethylation and cancer. In total, the 70 meta-analyses produced significant results under a random-effects model with odds ratios that ranged from 1.94 to 26.60, with the summary effect being in favor of the unmethylated group in all cases. Three of the strong evidence associations involve RASSF1 methylation on bladder cancer risk (OR = 18.46; 95% CI: 12.69-26.85; I² = 0%), MGMT methylation on NSCLC (OR = 4.25; 95% CI: 2.83-6.38; I² = 22.4%) and RARB methylation on prostate cancer (OR = 6.87; 95% CI: 4.68-10.08; I² = 0%). Meta-analyses showed a moderate quality, AMSTAR score ranging from 4 to 9 (Mdn = 8; IQR: 7.0 to 8.0). As primary studies and meta-analyses on the subject accumulate, more genetic loci may be found to be highly associated with specific cancer types and hence the biomarker sets will become wider.

Th2/Th17 cytokine profile in phenotyped Greek asthmatics and relationship to biomarkers of inflammation

OBJECTIVE

The aim of the present study was to investigate the Th2/Th17 pathway in asthmatic patients and also the relationship to asthma severity and biomarkers of inflammation.

METHODS

90 asthmatic patients, 51 patients with severe, 39 patients with mild asthma and 98 healthy controls were included. Skin prick tests, blood eosinophils, total serum IgE and exhaled FeNO were evaluated. Serum levels of IL-4, IL-5, IL-13, IL-6, IL-17A, IL-23 and TGFβ1 were determined by Flow Cytometry using a panel kit (AimPlex Biosciences). The SNP of IL17A (rs17880588) was genotyped using reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

The genotype of the SNP in IL17A (rs 17880588) was similar among all three groups. Serum levels of IL-4, IL-5, IL-13, IL-6, IL-17A and IL-23 were higher in asthmatics compared to controls (p < 0.05). In addition, IL-17A and IL-4 serum levels were found significantly elevated in patients with allergic asthma (p < 0.05). Furthermore, IL-4, IL-5, IL-13 and IL-23 were found significantly higher in patients with eosinophil cut off values above 300 cells/μl (p < 0.05). IL-17A levels were positively correlated with FeNO values in severe asthmatics with eosinophils>400 cells/μl.

CONCLUSIONS

The above findings suggest the coexistence of Th2/Th17 pathway in severe, eosinophilic and in allergic asthma.

Osteoprotegerin increases parallel to insulin resistance in obese adolescents

Purpose/Aim of the Study: Osteoprotegerin (OPG) is an α tumor necrosis factor receptor superfamily glucoprotein that acts as a decoy receptor for the receptor activator of nuclear factor kappa B ligand (RANKL), exerting an antiresoptive bone effect. It was recently shown that OPG/RANKL axis is activated during vascular calcification, contributing to atherosclerotic lesions formation. Additionally, OPG levels are charachterized as an independent risk factor for overall vascular mortality in obese adults. We aimed to investigate OPG levels in children/adolescents with obesity and explore possible relations with obesity-related insulin resistance (IR).

MATERIAL AND METHODS

A total of 160 participants (85 obese) were enrolled. Participants with obesity underwent an oral glucose tolerance test. IR was evaluated according to the homeostasis model assessment-insulin resistance index. Serum OPG levels were determined.

RESULTS

OPG levels did not differ significantly between obese subjects and controls in the total sample (p = 0.133). However, in the adolescents' subgroup, serum OPG levels were significantly increased in obesity (p = 0.019). After stratifying participants according to their IR status, only subjects with both obesity and IR exhibited increased OPG levels compared to controls (p < 0.001). Factor analysis further associated OPG levels variation to insulin levels variation and to IR.

CONCLUSIONS

Obese individuals demonstrate increased serum OPG levels during puberty. Obesity per se is not the potent factor for this increase; indeed, IR accompanying obesity seems to exert a fundamental role in OPG upregulation.

Age-dependent methylation in epigenetic clock CpGs is associated with G-quadruplex, co-transcriptionally formed RNA structures and tentative splice sites

Horvath's epigenetic clock consists of 353 CpGs whose methylation levels can accurately predict the age of individuals. Using bioinformatics analysis, we investigated the conformation, energy characteristics and presence of tentative splice sites of the sequences surrounding the epigenetic clock CpGs, in relation to the median methylation changes in different ages, the presence of CpG islands and their position in genes. Common characteristics in the 100 nt sequences surrounding the epigenetic clock CpGs are G-quadruplexes and/or tentative splice site motifs. Median methylation increases significantly in sequences which adopt less stable structures during transcription. Methylation is higher when CpGs overlap with G-quadruplexes than when they precede them. Median methylation in epigenetic clock CpGs is higher in sequences expressed as single products rather than in multiple products and those containing single donors and multiple acceptors. Age-related methylation variation is significant in sequences without G-quadruplexes, particularly those producing low stability nascent RNA and those with splice sites. CpGs in sequences close to transcription start sites and those which are possibly never expressed (hypothetical proteins) undergo similar extent of age-related median methylation decrease and increase. Preservation of methylation is observed in CpG islands without G-quadruplexes, contrary to CpGs far from CpG islands (open sea). Sequences containing G-quadruplexes and RNA pseudoknots, determining the recognition by H3K27 histone methyltransferase, are hypomethylated. The presented structural DNA and co-transcriptional RNA analysis of epigenetic clock sequences, foreshadows the association of age-related methylation changes with the principle biological processes of DNA and histone methylation, splicing and chromatin silencing.

Are expanded alleles of the FMR1 gene related to unexplained recurrent miscarriages?

BACKGROUND

In women with recurrent miscarriages, up to 50 % of those cases remain unexplained. In this study, we evaluated the impact of Cytosine/Guanine/Guanine (CGG)  trinucleotide expansions of the fragile-X mental retardation 1 (FMR1) gene in women with unexplained recurrent miscarriages.

METHODS

This is a prospective case-control pilot study involving 49 women with unexplained recurrent miscarriages and 49 age-matched controls with documented fertility. The case group consisted of women with a history of two or more consecutive miscarriages, in whom no known factor could be identified. The maximum age of recruitment was 40 years. We obtained blood samples that were checked, using polymerase chain reaction with electrophoresis, for the presence of expanded alleles of the FMR1 gene. We further evaluated using sequencing analysis, those women marked as positive. We set the limit at more than 40 repeats.

RESULTS

The repeat sizes of CGG expansion in the FMR1 gene differ significantly in the two population groups (p =0.027). We found four women in the miscarriage group and one in the control group positive for carrying premutation alleles (Odds ratio: 4.267, confidence interval: 0.459-39.629). All the positive cases involved intermediate zone carriers. We found no association between the number of abortions each woman had, and her respective CGG repeat number (p =0.255).

CONCLUSIONS

Many couples are desperately looking for the cause of their recurrent miscarriage suffering. The CGG expanded allele of the FMR1 gene is possibly to be blamed in some of these cases. More studies are needed to support the results of this prototype study. HIPPOKRATIA 2018, 22(3): 132-136.

Elevated plasma levels of miR-29a are associated with hemolysis in patients with hypertrophic cardiomyopathy

BACKGROUND

miR-29a is a small non-coding RNA that is known to repress collagen synthesis. Interestingly, elevated plasma miR-29a was reported to correlate with pronounced myocardial fibrosis in patients with hypertrophic cardiomyopathy. The objective of this study was to elucidate the origin of plasma miR-29a, and evaluate its significance as a biomarker.

METHODS

miR-29a expression was evaluated in plasma (n=50) and myocardial samples (n=4) from patients with hypertrophic cardiomyopathy using RT-qPCR.

RESULTS

Although miR-29a was highly expressed in the myocardium, miR-29a plasma levels did not show any correlation with serum troponin I levels (r_s=-0.12, p=0.43), and the heart does not release significant amounts of miR-29a into the circulation via exosome secretion. Conversely, miR-29a was present in red blood cells, and plasma levels correlated significantly with markers of hemolysis: lactic dehydrogenase (r_s=0.36, p=0.01) and the absorbance of oxyhemoglobin at 414nm (r_s=0.39, p=0.006). Furthermore, the association between serum haptoglobin and the maximal blood flow velocity in the left ventricle outflow tract (r_s=-0.42, p=0.008) indicated that intravascular hemolysis is a manifestation of the disease.

CONCLUSIONS

miR-29a is highly expressed in myocardial tissue from patients with hypertrophic cardiomyopathy. In contrast, plasma miR-29a is primarily of nonmyocardial origin and is correlated significantly with the extent of hemolysis observed in these patients.

An initially unidentified case of urinary tract infection due to Aerococcus urinae

Aerococcus urinae is a microorganism responsible for urinary tract and blood stream infections which are rarely reported in clinical practice. However, it has been proposed that the infrequency of such reports may be partially due to difficulties related to pathogen identification. We present here a case of an elderly male patient with urinary tract infection where A. urinae was initially not identified by a private microbiology laboratory. Our report highlights the need to consider A. urinae as a causative agent of urinary tract infections because if not identified and properly treated it may lead to endocarditis or septicemia.

Serum humanin concentrations in women with pre-eclampsia compared to women with uncomplicated pregnancies

PURPOSE

To compare serum humanin concentrations in pregnant women with and without pre-eclampsia (PE).

MATERIALS AND METHODS

A case-control study where pregnant women (PE group, n = 37; control group, n = 34) studied through history parameters (gynecological, obstetrical, personal, and family), physical and sonographic examination parameters [body mass index (BMI), blood pressure obstetrical ultrasound], and biochemical/hormonal assays [creatinine, urea, serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), uric acid, platelets, urinary protein, and humanin].

RESULTS

There was no difference in basic characteristics between women with PE and control, except in parity and gravidity. Humanin concentrations were higher in women with PE compared to controls (422.2 ± 33.5 vs. 319.1 ± 28.1 pg/ml, p = 0.023). In a binary logistic analysis, humanin was associated with the presence of PE [odds ratio 1.003, 95% confidence interval (CI); 1.000-1.006]. The ability of humanin to discriminate between women with PE and controls was evaluated by receiver operation characteristics (ROC) analysis [area under the curve (AUC) 0.639, 95% CI; 0.510-0.768, p = 0.045].

CONCLUSIONS

Serum humanin concentrations are increased in women with PE, compared to women with uncomplicated pregnancies, suggesting a potential protective role of humanin against the oxidative stress and endothelial dysfunction occurring in PE.

Increased Δ133p53 mRNA in lung carcinoma corresponds with reduction of p21 expression

Modification of p53 expression levels and its principle apoptosis and cell cycle regulatory partners, mouse double minute 2 homolog (MDM-2) and p21, has been previously reported in various types of cancer. In the current study, the expression of Δ133p53 isoforms was investigated in lung carcinomas with respect to the expression of the aforementioned genes. The expression of p53 full-length transcript and Δ133p53 isoforms α, β and γ transcripts, MDM-2 and p21 transcripts were determined by reverse transcription-quantitative polymerase chain reaction, in total RNA isolated from 17 lung carcinoma specimens and 17 corresponding adjacent non-cancerous tissues. RNA expression analysis was performed according to the Pfaffl equation and Rest tool using β-actin as a reference gene. Detection of the above proteins was additionally performed by western blotting. Significant overexpression of the Δ133p53 mRNAs was observed in cancerous as compared with adjacent non-cancerous tissues (3.94-fold), whereas full-length p53 and MDM-2 expression exhibited a smaller, however significant, increase. The expression of the p21 transcript was significantly reduced in cancerous specimens. Δ133p53 and p21 expression levels varied in parallel, however were not significantly correlated. p53 full-length protein expression observed by western blot analysis strongly varied from the Δ133p53 isoforms, however MDM-2 protein isoforms were not detectable and p21 protein was more abundant in non-cancerous tissues. In conclusion, Δ133p53 mRNA levels is suggested as a potentially useful marker of malignancy in lung cancer. The absence of Δ133p53 protein in lung carcinomas, which overexpress Δ133p53 transcripts, may indicate the role of the latter in post-transcriptional regulation through RNA interference in the cell cycle and apoptosis.

Association of two synonymous splicing-associated CpG single nucleotide polymorphisms in calpain 10 and solute carrier family 2 member 2 with type 2 diabetes

Coding synonymous single nucleotide polymorphisms (SNPs) have attracted little attention until recently. However, such SNPs located in epigenetic, CpG sites modifying exonic splicing enhancers (ESEs) can be informative with regards to the recently verified association of intragenic methylation and splicing. The present study describes the association of type 2 diabetes (T2D) with the exonic, synonymous, epigenetic SNPs, rs3749166 in calpain 10 (CAPN10) glucose transporter (GLUT4) translocator and rs5404 in solute carrier family 2, member 2 (SLC2A2), also termed GLUT2, which, according to prior bioinformatic analysis, strongly modify the splicing potential of glucose transport-associated genes. Previous association studies reveal that only rs5404 exhibits a strong negative T2D association, while data on the CAPN10 polymorphism are contradictory. In the present study DNA from blood samples of 99 Greek non-diabetic control subjects and 71 T2D patients was analyzed. In addition, relevant publicly available cases (40) resulting from examination of 110 Personal Genome Project data files were analyzed. The frequency of the rs3749166 A allele, was similar in the patients and non-diabetic control subjects. However, AG heterozygotes were more frequent among patients (73.24% for Greek patients and 54.55% for corresponding non-diabetic control subjects; P=0.0262; total cases, 52.99 and 75.00%, respectively; P=0.0039). The rs5404 T allele was only observed in CT heterozygotes (Greek non-diabetic control subjects, 39.39% and Greek patients, 22.54%; P=0.0205; total cases, 34.69 and 21.28%, respectively; P=0.0258). Notably, only one genotype, heterozygous AG/CC, was T2D-associated (Greek non-diabetic control subjects, 29.29% and Greek patients, 56.33%; P=0.004; total cases, 32.84 and 56.58%, respectively; P=0.0008). Furthermore, AG/CC was strongly associated with very high (≥8.5%) glycosylated plasma hemoglobin levels among patients (P=0.0002 for all cases). These results reveal the complex heterozygotic SNP association with T2D, and indicate possible synergies of these epigenetic, splicing-regulatory, synonymous SNPs, which modify the splicing potential of two alternative glucose transport-associated genes.

Peripheral blood monocytes can differentiate into efficient insulin-producing cells in vitro

BACKGROUND

Recent studies provide evidence that peripheral blood monocytes have the ability to differentiate into mesenchymal-like cells. The ability of cultured monocytes to differentiate and produce insulin in vitro is analysed in the present study.

METHODS

Peripheral blood monocytes were isolated from healthy donors and cultivated for fourteen days. Growth factors and liraglutide were used to induce pancreatic differentiation in most of the cultures. The growth factors were: monocyte colony-stimulating factor, interleukin-3, hepatocyte growth factor and epidermal growth factor. The rest of the cultures were cultivated only with nutrient medium and human serum. Insulin levels were measured by an enzyme-linked immunosorbent assay. Cellular morphology was observed using optical and electron microscopy. Cell membrane receptors were detected by flow cytometry.

RESULTS

Monocytes were able to synthesize and excrete high levels of insulin after seven days in culture. A further increase in the excretion of insulin was observed after fourteen days. Cells were also able to differentiate and synthesize insulin, even if no growth factors were added to the culture medium. Some of the cultures were able to excrete insulin in a glucose-dependent manner. Differentiated monocytes were connected to neighbouring cells with axons and resembled the morphology of mesenchymal, dendritic and myeloid-progenitor cells. Cells retained their mature receptors and simultaneously developed immature receptors on their membrane.

CONCLUSIONS

Monocytes can acquire morphological properties of multipotent cells when they are cultivated under specific conditions in vitro. Differentiated monocytes are able to synthesize and excrete insulin. Hippokratia 2015; 19 (4): 344-351.

Mechanical aberrations in hypetrophic cardiomyopathy: emerging concepts

Hypertrophic cardiomyopathy is the most common monogenic disorder in cardiology. Despite important advances in understanding disease pathogenesis, it is not clear how flaws in individual sarcomere components are responsible for the observed phenotype. The aim of this article is to provide a brief interpretative analysis of some currently proposed pathophysiological mechanisms of hypertrophic cardiomyopathy, with a special emphasis on alterations in the cardiac mechanical properties.

Detection and typing of human papillomaviruses (HPV) in malignant, dysplastic, nondysplastic and normal oral epithelium by nested polymerase chain reaction, immunohistochemistry and transitional electron microscopy in patients of northern Greece

OBJECTIVES

To evaluate the role of HPV in oral carcinogenesis, we examined the prevalence of HPV in malignant, potentially malignant and normal oral epithelium and studied the relation of HPV prevalence with other factors obtained from the patient's records.

MATERIALS AND METHODS

Our material consisted of 291 tissue specimens from 258 individuals. From every individual formalin fixed and paraffin embedded tissues were examined by nested Polymerase Chain Reaction (NPCR) for the detection of HPV DNA and by immunohistochemistry (IHC) for the in situ detection of HPV L1 protein. Positive PCR products were sequenced in order to type HPVs. Also 33 fresh tissues were obtained, fixed and used to detect HPV particles by transitional electron microscopy (TEM).

RESULTS

HPV was detected in 32.9% of the tissue specimens by NPCR, in 4.7% by immunohistochemistry and in 28.1% by TEM. In detail, by nested PCR HPV L1 DNA was detected in 40% of normal tissues, 40% of fibromas, 35.8% of non-dysplastic leukoplakias, 31.6% of dysplastic leukoplakias and 22.2% of oral squamous cell carcinomas. The HPV viral load of 96.5% of the samples was very low (1 viral copy per 10(2)-10(4) cells). HPV16 prevails in all histological groups in 89-100%.

CONCLUSION

We conclude that HPV does not seem, from the specific sample examined, to play a substantial role in oral carcinogenesis. However, it cannot be excluded that HPV could be involved in oral carcinogenesis only in cases with high viral load or at early stages of carcinogenesis possibly through the hit-and-run mechanism.

Numb and Alzheimer's disease: the current picture

Twenty-three years ago, numb was identified as a critical regulator in Drosophila sensory organ precursor cell asymmetric divisions. Beyond the recently recognized role in carcinogenesis, Numb seems to be important in Alzheimer’s disease. This assertion comes from the involvement in various processes such as synapse morphogenesis, amyloid precursor protein trafficking, notch signaling, and neurogenesis. The purpose of the present mini-review is to provide the current picture of Numb’s participation in mechanisms underlying Alzheimer’s disease pathogenesis and emphasize potential aspects for future research.

Correlation of fl/d3 polymorphism of growth hormone receptor with the first- and second-year response to recombinant human growth hormone therapy in pre-pubertal Greek children with idiopathic isolated growth hormone deficiency

BACKGROUND

fl/d3 polymorphism in human GH receptor was correlated with the response to GH therapy in different groups of children with short stature.

AIM

This is a 2-yr retrospective study which evaluates the influence of fl/d3 polymorphism to the 1st-and 2nd-year response to GH replacement therapy in Greek children with isolated GH deficiency (GHD).

SUBJECTS AND METHODS

A total number of 195 pre-pubertal Greek children were studied (121 controls and 74 patients with GH peak <10 ng/ml). Patients with deficiency were treated with exogenous GH at a mean dose of 28.8 μg/kg.d. Multiplex PCR was used to genotype all children for fl/d3 polymorphism, followed by statistical analysis. The main parameters which were used to assess the association of genotype with the response to GH replacement were height SD score (SDS), height gain SDS, and growth velocity (GV) expressed as cm/yr and SDS.

RESULTS

Our results revealed that the frequency of d3-homozygosity in the Greek population was 8.26%. No association was detected between the presence or abcense of GHD and genotype. Moreover, no connection between genotype and sex was observed. First-year height SDS, height gain SDS, and GV SDS were significantly higher in d3-carriers (p<0.05). However, this difference did not appear in the 2nd year of treatment.

CONCLUSIONS

In our study, the d3-polymorphism seems to be associated with a higher efficacy to GH replacement, at least at the beginning of the treatment.

Recovering circulating extracellular or cell-free RNA from bodily fluids

The presence of extracellular circulating or cell-free RNA in biological fluids is becoming a promising diagnostic tool for non invasive and cost effective cancer detection. Extracellular RNA or miRNA as biological marker could be used either for the early detection and diagnosis of the disease or as a marker of recurrence patterns and surveillance. In this review article, we refer to the origin of the circulating extracellular RNA, we summarise the data on the biological fluids (serum/plasma, saliva, urine, cerebrospinal fluid and bronchial lavage fluid) of patients suffering from various types of malignancies reported to contain a substantial amount of circulating extracellular (or cell-free) RNAs and we discuss the appropriate reagents and methodologies needed to be employed in order to obtain RNA material of high quality and integrity for the majority of the experimental methods used in RNA expression analysis. Furthermore, we discuss the advantages and disadvantages of the RT-PCR or microarray methodology which are the methods more often employed in procedures of extracellular RNA analysis.

Salivary markers for oral cancer detection

Oral cancer refers to all malignancies that arise in the oral cavity, lips and pharynx, with 90% of all oral cancers being oral squamous cell carcinoma. Despite the recent treatment advances, oral cancer is reported as having one of the highest mortality ratios amongst other malignancies and this can much be attributed to the late diagnosis of the disease. Saliva has long been tested as a valuable tool for drug monitoring and the diagnosis systemic diseases among which oral cancer. The new emerging technologies in molecular biology have enabled the discovery of new molecular markers (DNA, RNA and protein markers) for oral cancer diagnosis and surveillance which are discussed in the current review.

Expression of Multidrug Resistance 1 (MDR1), Multidrug Resistance-Related Protein 1 (MRP1), Lung Resistance Protein (LRP), and Breast Cancer Resistance Protein (BCRP) Genes and Clinical Outcome in Childhood Acute Lymphoblastic Leukemia

The aim of this prospective study was to analyze the expression of messenger RNA of genes, such as MDR1, MRP1, BCRP, and LRP, implicated in the mechanism of multidrug resistance (MDR) in relation to the response to induction chemotherapy and relapse and these genes' correlation with each other and with pretreatment laboratory and clinical characteristics. We prospectively studied 49 children (26 boys and 23 girls) with acute lymphoblastic leukemia (ALL) (median age, 5.5 years; range, 15 months to 12.5 years) who were treated with the BFM95 chemotherapy protocol. We used bone marrow mononuclear cells from 7 healthy children as controls. The expression of MDR genes and the beta-actin housekeeping gene was detected by the reverse transcription-polymerase chain reaction with the appropriate primers. The mean expression of each MDR gene was significantly higher in the patients than in the control group (P < .01). We found statistically significant correlations between MRP1 and LRP expression and between MRP1 or LRP expression and MDR1 expression (P < .05). High expression for the MDR1 gene was found in 18 patients (36.7%), and their prognoses were significantly worse than those with low expression (event-free survival, 55.56% versus 86.67%; P = .03, log-rank test). Expression of each of the MDR genes was independent of the initial white blood cell count, immunophenotype, National Cancer Institute risk classification, and prednisone response. Interestingly, MDR1 expression was significantly higher at relapse than at diagnosis for 4 sample pairs. Evaluation of MDR1 expression at diagnosis of childhood ALL may contribute to the early identification of patients at risk of treatment failure.

Non-CpG cytosine methylation of p53 exon 5 in non-small cell lung carcinoma

Non-CpG methylation of cytosine residues, a mechanism associated with regulation of gene expression, has not been investigated in human cancer until now. Analysis of the p53 exon 5 mutation spectrum in mutation databases for lung cancer reveals frequent GC>AT transitions, several of which occur at non-CpG sequences. To investigate the involvement of cytosine methylation in this mutagenesis process, we analyzed the methylation profile of p53 exon 5, in lung carcinoma. In this report, we present evidence that extensive clustered non-CpG methylation is observed in three regions of this exon, namely the sequences spanning codons 156-159, 175-179 and the 3' splice site, as well as in scattered CpA sequences. This methylation pattern was verified using direct methylation sequencing, and a two-stage methylation-specific PCR assay (MSP), designed for the detection of methylation in a GC rich region (oligo C sequence, of codons 175-179) of exon 5. The results from this MSP assay reveal that DNA from cancerous specimens was more heavily methylated in non-CpG cytosines, compared to that from non-cancerous lung tissue of cancer patients (14/19 cancerous and 6/19 non-cancerous, respectively). DNA isolated from human leucocytes and some non-cancerous specimens (2/19) was free of non-CpG methylation. Careful analysis of the mutations reported in p53 mutation databases also provides corroborating evidence that the high incidence of GC>AT mutations in the p53 gene, observed in lung cancer, might also be related to non-CpG methylation, as well as to the overall increase of methylation sites in this locus.

Introduction of the negative selection marker into replacement vectors by a single ligation step

Gene targeting is a powerful method for introducing mutations into the genome of embryonic stem cells. The most widely used approach is the positive-negative selection method in which a gene encoding a negative selection marker is cloned into the replacement vector to obtain an enrichment of properly targeted clones. Here, we present an alternative means to introduce any given negative selection marker at the ends of a replacement vector using a single ligation step, thereby avoiding laborious cloning procedures. Our results demonstrate that this fast and simple method consistently provides a high level of enrichment of appropriately targeted clones.

Autocrine-paracrine regulation of hippocampal neuron survival by IGF-1 and the neurotrophins BDNF, NT-3 and NT-4

In contrast to sympathetic and sensory neurons in the peripheral nervous system, the neurotrophic requirements for neurons in the central nervous system (CNS) have not been clearly identified. The inactivation of specific neurotrophic factors and their receptors by gene targeting has shown that there are no major changes in neuron numbers in the CNS. This suggests an overlap between the action of different neurotrophic factors in the brain during development. Here we have studied the survival of hippocampal neurons prepared from embryonic rats using different culture conditions. Whereas the hippocampal neurons survive well in culture when plated at high density, they die at lower cell densities in the absence of appropriate neurotrophic factors. Under the latter conditions, both insulin-like growth factor-1 (IGF-1) and neurotrophins - brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and neurotrophin-4 (NT-4) - rescued a large proportion of cultured neurons. In addition, hippocampal neurons from BDNF knockout mice exhibited enhanced cell death compared with cells from wild-type animals. BDNF and IGF-1 both increased the survival of the hippocampal neurons lacking BDNF, showing complementary action for these factors in supporting survival. Blocking antibodies against NT-3 and IGF-1 decreased hippocampal neuron survival at low cell densities, showing autocrine or paracrine action of the factors. At higher cell densities, however, the antibodies had no effect, demonstrating that there is a sufficient amount of endogenous factors in supporting survival. Blocking antibodies against NT-3 and IGF-1 decreased hippocampal neurons depend for survival on local neurotrophic factors such as IGF-1, BDNF and NT-3, which act in an autocrine/paracrine manner. The multifactorial support of hippocampal neurons ensures a maximal degree of neuron survival even in the absence of an individual factor

bcl-2 messenger RNA is localized in neurons of the developing and adult rat brain

Overexpression of the proto-oncogene bcl-2 blocks programmed cell death in sympathetic and sensory neurons that normally die after the withdrawal of neurotrophic factors. The role of endogenous bcl-2 in the development and function of the peripheral and central nervous system is, however, not known. We have found that low levels of bcl-2 messenger RNA are widely distributed in the adult and developing rat brain. In situ hybridization localized bcl-2 messenger RNA in mitral cells of the olfactory bulb, granule and pyramidal neurons of hippocampus, pontine nuclei, cerebellar granule neurons, and in ependymal cells in adult rat brain. bcl-2 messenger RNA levels were higher in late prenatal development than in postnatal and adult brain. High levels of bcl-2 messenger RNA were expressed in the neuroepithelium and in the cortical plate in prenatal cortex. During postnatal development the distribution of the message resembled that found in adult brain. We have also tested the hypothesis that induction of bcl-2 messenger RNA expression might be part of the survival-promoting action of neurotrophic factors. Brain-derived neurotrophic factor, which supports survival of cultured cerebellar granule neurons, failed to influence the levels of bcl-2 messenger RNA in these cultures.

Fibroblast growth factor-5 promotes differentiation of cultured rat septal cholinergic and raphe serotonergic neurons: comparison with the effects of neurotrophins

Fibroblast growth factor-5 (FGF-5) is a member of the fibroblast growth factor gene family, which has a signal sequence characteristic of secretory proteins. FGF-5 mRNA has previously been shown to be present in the adult mouse brain. Here we demonstrate that recombinant FGF-5 has neurotrophic activity on cultured rat septal cholinergic and raphe serotonergic neurons. The effect of FGF-5 on serotonin uptake was stronger than that evoked with either brain-derived neurotrophic factor or neurotrophin-3. FGF-5 also increased the choline acetyltransferase activity of cultured rat septal cholinergic neurons, the effect being additive to that of nerve growth factor. In situ hybridization experiments and immunohistochemistry using a specific anti-FGF-5 antibody demonstrated that FGF-5 is expressed in rat hippocampal neurons. Like nerve growth factor mRNA, the levels of FGF-5 mRNA in the rat hippocampus increased substantially during early postnatal development. In addition, injection of the muscarinic receptor agonist pilocarpine elevated FGF-5 mRNA. The presence of the secretory FGF-5 in the rat hippocampus, a target field of septal cholinergic and raphe serotonergic neurons, suggests that FGF-5 acts as a trophic factor for these neurons also in vivo.

Structure and expression analysis of a member of the human glutamate dehydrogenase (GLUD) gene family mapped to chromosome 10p11.2

Glutamate dehydrogenase (GLUD) is a key metabolic enzyme of the mitochondrion, playing an important role in mammalian neuronal transmission. GLUD deficiency has been associated with certain forms of neurodegeneration in the human cerebellum. Genomic DNA blot hybridization analysis and identification of a large number of GLUD-specific genomic clones have suggested that human GLUD is encoded by a multigene family consisting of at least six members. A functional GLUD gene, GLUD1, has been mapped to chromosome 10q22.3-23 and a full-length "processed" GLUD gene, GLUDP1, to chromosome Xq22-23. In the context of studing the structure, the role, and the chromosomal organization of the other family members, we have analysed in detail, a cosmid clone solely reactive with the 3' region of the GLUD cDNA. Structure and expression analysis of its GLUD-specific region suggests that it represents a truncated "processed" GLUD pseudogene. Fluorescence in situ hybridization using the entire cosmid as a probe, mapped this GLUD gene locus, termed GLUDP5, to chromosome 10p11.2.

The human glutamate dehydrogenase gene family: gene organization and structural characterization

Glutamate dehydrogenase is a mitochondrially located, key metabolic enzyme. In addition to its general metabolic role, GLUD is important in neurotransmission. Significant alterations in GLUD enzymatic activity have been associated with certain neurodegenerative human disorders. Although a single species of human GLUD cDNA molecule has been identified so far, both genomic DNA Southern and cytogenetic analyses have indicated the presence of a GLUD gene family. Screening of a human genomic lambda-phage library with the GLUD cDNA, led us to the isolation of several clones divided into five structurally distinct contigs. We have confirmed the presence of all GLUD-specific sequences in the human genome by detailed genomic Southern analysis. This study allowed the identification of the entire functional GLUD gene, named GLUD1. The GLUD1 gene is about 45 kb long and it is organized into 13 exons. Its nucleotide sequence, exon-intron boundaries, and transcription start sites were determined. Potential binding sites for various regulatory factors such as Sp1, AP-1, and AP-2 were recognized at the promoter region of the gene. The members of the other contigs showed an organization clearly different from GLUD1. Two distinct GLUD-specific gene loci, termed GLUDP2 and GLUDP3, possibly represent truncated pseudogenes. Their high degree of similarity to GLUD1 is limited to the region surrounding exons 2, 3, and 4. Finally, two additional GLUD-specific genomic sequences, termed GLUDP4 and GLUDP5, are structurally similar with the 3' part of the GLUD cDNA sequence. These loci probably represent truncated GLUD pseudogenes generated by retrotransposition. The data presented here suggest that all human GLUD pseudogenes have diverged recently in evolution.

Molecular cloning, structure and expression analysis of a full-length mouse brain glutamate dehydrogenase cDNA

We isolated and analysed a full-length mouse brain glutamate dehydrogenase (GLUD) cDNA as a preliminary step to use the mouse model for the investigation of GLUD function in neurotransmission and neurodegeneration. GLUD coding sequences were found highly conserved among mouse, human and rat. Northern blots revealed two transcripts with different ratios in different mouse organs implying some mechanism of tissue-specific expression. In contrast to human, mouse GLUD gene family appears not to contain an intronless member.

Chromosomal mapping of glutamate dehydrogenase gene sequences to mouse chromosomes 7 and 14

Glutamate dehydrogenase (GLUD) plays an important role in mammalian neuronal transmission. In human, GLUD is encoded by a small gene family. To determine whether defects in Glud genes are associated with known neurological mutations in the mouse and to contribute to the comparative mapping of homologous genes in man and mouse, the chromosomal location of genes reactive with a mouse brain GLUD cDNA were determined. Genomic Southern analysis of a well-characterized panel of Chinese hamster x mouse somatic cell hybrids identified two GLUD-reactive loci, one residing on mouse Chromosome 14 and the other on Chromosome 7. Progeny of an intersubspecies backcross were used to map one of these genes, Glud, proximal to Np-1 on Chromosome 14, but no restriction fragment polymorphisms could be identified for the second locus, Glud-2.

Isolation and characterization of cDNA clones encoding human liver glutamate dehydrogenase: evidence for a small gene family

We have isolated a series of human liver cDNA clones encoding glutamate dehydrogenase. The cDNA-derived protein sequence specifies a single 558-amino acid long polypeptide including a cleavable signal sequence of 53 amino acids. Blotting analysis of RNA from human, monkey, and rabbit showed that glutamate dehydrogenase mRNA is present in various amounts in all tissues tested. Glutamate dehydrogenase mRNAs are of four sizes and are found in different ratios in different tissues; the predominant ones are approximately 3.5 and approximately 2.9 kilobases. Blot hybridization of human genomic DNA to nonoverlapping cDNA fragments revealed multiple bands, many of which hybridize with two or more probes in a manner inconsistent with the existence of a single GLUD gene. Moreover, two separate 36-base synthetic oligonucleotides corresponding to the coding region hybridize to multiple genomic fragments, confirming the existence of more than one GLUD-related gene in human.