Widespread transcriptional disruption of the microRNA biogenesis machinery in brain and peripheral tissues of individuals with schizophrenia.

In schizophrenia, altered transcription in brain and peripheral tissues may be due to altered expression of the microRNA biogenesis machinery genes. In this study, we explore the expression of these genes both at the cerebral and peripheral levels. We used shinyGEO application to analyze gene expression from ten Gene Expression Omnibus datasets, in order to perform differential expression analyses for eight genes encoding the microRNA biogenesis machinery. First, we compared expression of the candidate genes between control subjects and individuals with schizophrenia in postmortem cerebral samples from seven different brain regions. Then, we compared the expression of the candidate genes between control subjects and individuals with schizophrenia in three peripheral tissues. In brain and peripheral tissues of individuals with schizophrenia, we report distinct altered expression patterns of the microRNA biogenesis machinery genes. In the dorsolateral prefrontal cortex, associative striatum and cerebellum of individuals with schizophrenia, we observed an overexpression pattern of some candidate genes suggesting a heightened miRNA production in these brain regions. Additionally, mixed transcriptional abnormalities were identified in the hippocampus. Moreover, in the blood and olfactory epithelium of individuals with schizophrenia, we observed distinct aberrant transcription patterns of the candidate genes. Remarkably, in individuals with schizophrenia, we report DICER1 overexpression in the dorsolateral prefrontal cortex, hippocampus and cerebellum as well as a congruent DICER1 upregulation in the blood compartment suggesting that it may represent a peripheral marker. Transcriptional disruption of the miRNA biogenesis machinery may contribute to schizophrenia pathogenesis both in brain and peripheral tissues.

Distinct Expression Pattern of Epigenetic Machinery Genes in Blood Leucocytes and Brain Cortex of Depressive Patients.

In major depressive disorder (MDD), altered gene expression in brain cortex and blood leucocytes may be due to aberrant expression of epigenetic machinery coding genes. Here, we explore the expression of these genes both at the central and peripheral levels. Using real-time quantitative PCR technique, we first measured expression levels of genes encoding DNA and histone modifying enzymes in the dorsolateral prefrontal cortex (DLPFC) and cingulate cortex (CC) of MDD patients (n = 24) and healthy controls (n = 12). For each brain structure, transcripts levels were compared between subject groups. In an exploratory analysis, we then compared the candidate gene expressions between a subgroup of MDD patients with psychotic characteristics (n = 13) and the group of healthy subjects (n = 12). Finally, we compared transcript levels of the candidate genes in blood leucocytes between separate samples of MDD patients (n = 17) and healthy controls (n = 16). In brain and blood leucocytes of MDD patients, we identified an overexpression of genes encoding enzymes which transfer repressive transcriptional marks: HDAC4-5-6-8 and DNMT3B in the DLPFC, HDAC2 in the CC and blood leucocytes. In the DLPFC of patients with psychotic characteristics, two genes (KAT2A and UBE2A) were additionally overexpressed suggesting a shift to a more transcriptionally permissive conformation of chromatin. Aberrant activation of epigenetic repressive systems may be involved in MDD pathogenesis both in brain tissue and blood leucocytes.

Leukocyte telomere length in mastocytosis: correlations with depression and perceived stress.

BACKGROUND: Mastocytosisis a rare disease associated with chronic symptoms related to mast cell mediator release. Patients with mastocytosis display high level of negative emotionality such as depression and stress sensibility. Brain mast cells are mainly localized in the diencephalon, which is linked to emotion regulatory systems. Negative emotionality has been shown to be associated with telomere shortening. Taken together these observations led us to hypothesize that mast cells activity could be involved in both negative emotionality and telomere shortening in mastocytosis. OBJECTIVE: To demonstrate a possible relationship between negative emotionality in mastocytosis and leukocytes telomere length. METHODS: Leukocyte telomere length and telomerase activity were measured among mastocytosis patients and were correlated with perceived stress and depression assessed by the Beck Depression Inventory revised and the Perceived Stress Scale. RESULTS: Mild-severe depression scores were frequent (78.9%) as well as high perceived stress (42.11%). Telomere length was correlated to perceived stress (r=0.77; p=0.0001) but not to depression in our population. Patients displaying Wild-type KIT significantly presented higher perceived stress levels. Patients with the D816VC KIT mutation who had high perceived stress scores displayed significantly shorter telomere but not if they had high depression scores. CONCLUSION: These findings suggest that high perceived stress in mastocytosis could accelerate the rate of leukocytes telomere shortening. Since mastocytosis is, by definition, a mast cell mediated disease; these cells could be involved in this phenomenon. Mechanistic causal relationships between these parameters need to be investigated.

Correlative gene expression pattern linking RNF123 to cellular stress-senescence genes in patients with depressive disorder: implication of DRD1 in the cerebral cortex.

BACKGROUND: The expression level of the RNF1213 gene in blood cells has been identified as a disease risk marker, more than ten years before the diagnosis of depression (Glahn et al., 2012). To explore the status of this gene in the acute depressive state we have quantified the expression of RNF123 in the blood leukocytes (N=17), dorsolateral prefrontal and cingulate cortex (N=24) of patients with diagnosed depression and of matched controls. We have measured the expression of the DRD1 gene as a "neuronal probe". We have also quantified the mRNA of six genes previously identified as markers of the biopsychological stress associated with major depression: FOS, DUSP1, OGG1, STMN1, p16(INK4a) and TERT. METHODS: The steady state of mRNA has been quantified by the real-time quantitative PCR technique. RESULTS: RNF123 was overexpressed by 45% in the cingulate cortex of patients with psychotic depression. There were distinct co-expression patterns of RNF123 and stress-related genes in the blood cells and brain cortex of patients, demonstrating a transcriptional regulatory shift. In both the prefrontal and cingulate cortex of these patients a strong correlation interlinked STMN1, TERT and DRD1 pointing to a role of these genes in dopamine signaling. LIMITATIONS: The two groups of patients were clinically heterogeneous. All the patients had received antidepressant treatment, details of which were not available. CONCLUSION: We did not identify RNF123 as a clinically relevant, peripheral state marker of depression, but our study probably lacked statistical power to detect small effect size. It is likely to be involved in distinct pleiotropic molecular pathways at peripheral (blood) and central (brain) level.

Up-regulation of leucocytes genes implicated in telomere dysfunction and cellular senescence correlates with depression and anxiety severity scores.

BACKGROUND: Major depressive disorder (MDD) is frequently associated with chronic medical illness responsible of increased disability and mortality. Inflammation and oxidative stress are considered to be the major mediators of the allostatic load, and has been shown to correlate with telomere erosion in the leucocytes of MDD patients, leading to the model of accelerated aging. However, the significance of telomere length as an exclusive biomarker of aging has been questioned on both methodological and biological grounds. Furthermore, telomeres significantly shorten only in patients with long lasting MDD. Sensitive and dynamic functional biomarkers of aging would be clinically useful to evaluate the somatic impact of MDD. METHODOLOGY: To address this issue we have measured in the blood leucocytes of MDD patients (N=17) and controls (N=16) the expression of two genes identified as robust biomarkers of human aging and telomere dysfunction: p16(INK4a) and STMN1. We have also quantified the transcripts of genes involved in the repair of oxidative DNA damage at telomeres (OGG1), telomere regulation and elongation (TERT), and in the response to biopsychological stress (FOS and DUSP1). RESULTS: The OGG1, p16(INK4a), and STMN1 gene were significantly up-regulated (25 to 100%) in the leucocytes of MDD patients. Expression of p16(INK4a) and STMN1 was directly correlated with anxiety scores in the depression group, and that of p16(INK4a), STMN and TERT with the depression and anxiety scores in the combined sample (MDD plus controls). Furthermore, we identified a unique correlative pattern of gene expression in the leucocytes of MDD subjects. CONCLUSIONS: Expression of p16(INK4) and STMN1 is a promising biomarker for future epidemiological assessment of the somatic impact of depressive and anxious symptoms, at both clinical and subclinical level in both depressive patients and general population.

Leukocyte telomere length: a focus on cerebrovascular events.

Telomeres are specialized DNA structures located at the ends of chromosomes. Their length is reduced at each cell cycle, especially when the cumulative burden of oxidative stress is high. The purpose of this study was to determine the associations between telomere length and clinical and biological risk factors in ischemic stroke patients. A total of 215 stroke patients hospitalized in the Dijon, France, stroke unit were prospectively and continuously included from January to September, 2004. The telomere length measured from peripheral blood leukocytes--leukocyte telomere length (LTL)--was determined by real-time quantitative polymerase chain reaction. The results were compared with clinical and biological variables of interest collected at admission to find significant associations. Possible relationships between LTL and stroke subtypes were evaluated. A multiple regression that included all the variables significantly associated (p<0.20) with LTL in univariate analysis and age and subtypes of stroke confirmed a significant association with age (p<0.001), homocysteinemia (p=0,049), and levels of both antiphospholipid antibodies (p=0.019) and triglycerides (p=0.007). Linearity was verified and confirmed for each variable. The subtype of stroke did not significantly affect telomere length. We were able to highlight significant associations between LTL and certain cerebrovascular risk factors in a general population of stroke patients. These associations did not depend on the ischemic stroke subtype.

Smoking and FOS expression from blood leukocyte transcripts in patients with coronary artery disease.

OBJECTIVE: Analysis of the leukocyte transriptome, in particular the Finkel-Biskis-Jinkins Osteosarcoma (c-Fos) gene, which has a prominent role in inflammation, provides new insights into atherosclerosis mechanisms. Although smoking is a major risk factor, the links between smoking status and coronary artery disease (CAD) remains unclear. We aimed to analyze the relationship between smoking status and c-Fos expression in circulating leukocytes of patients with CAD. METHODS: c-Fos expression was measured by RT-Q-PCR, from blood leukocytes of 239 consecutive patients after acute myocardial infarction (MI). The patients were asked about their smoking status and stratified into 3 groups: current smokers (CS) (N = 85), past smokers (PS) (N = 78) and never smokers (NS) (N = 76). RESULTS: NS had a higher risk profile including hypertension, and CS were younger than PS and NS (-13 years and 17 years respectively). There was only a trend towards lower CRP levels in NS and PS than in CS. The mean c-Fos transcript level was slightly higher in CS than in PS and NS (0.924 vs. 0.908 and 0.861 AU, respectively; p = 0.005). By univariate analysis, neither age, nor sex, nor CRP nor white blood cell count was associated with c-Fos transcript levels. By multivariate analysis, CS (vs. PS + NS) was the strongest predictor of the c-Fos transcript level, (B = 0.042 ± 0.014, p = 0.003), even after adjustment for confounding factors (i.e. hypertension, chronic medication, family history of CAD, and prior MI). CONCLUSION: Our work suggests that c-Fos transcript level in blood leukocyte could be considered a cumulative biomarker of smoking. As the c-Fos gene has been put forward as a new factor in the progression and severity of atherosclerosis, it could be considered a novel potential pathway of tobacco toxicity in coronary artery disease.

Circulating leukocyte telomere length and oxidative stress: a new target for statin therapy.

OBJECTIVES: We investigated the relationship between prior statin therapy and leukocyte telomere length (LTL), as well as their interaction with potential new biomarkers of oxidative deoxyribonucleic acid (DNA) lesions and reactive oxygen species-induced inflammation. METHODS AND RESULTS: From patients admitted for an acute myocardial infarction, LTL was assessed by quantitative polymerase chain reaction (Q-PCR), and leukocyte Finkel-Biskis-Jinkins osteosarcoma (FOS) and 8-oxoguanine DNA glycosylase (OGG1) messenger ribonucleic acid (mRNA) levels were measured by retrotranscription Q-PCR. Patients under prior chronic statin therapy were compared with patients without statin therapy. Although patients on statin therapy were older, their mean LTL was longer than patients not under statin therapy (1.29 ± 0.11 vs. 1.25 ± 0.11 T/S ratio, p = 0.008). In contrast, FOS and OGG1 mRNA levels were similar for the 2 groups. LTL decreased with increasing age, FOS, and OGG1 mRNA levels. Statin therapy remained associated with longer LTL, even after adjustment for confounding factors (p = 0.001), and in younger patients (≤ 64 y). Even in groups matched for propensity scores for statin use, LTL was markedly longer in patients under statin therapy. CONCLUSIONS: Our observational study showed that statin therapy was associated with longer LTL. These data bring to light opportunities to identify new targets for early primary preventive treatment strategies. Moreover, our study raised FOS and OGG1 as new relevant biomarkers of LTL.

Activation of a ΔFOSB dependent gene expression pattern in the dorsolateral prefrontal cortex of patients with major depressive disorder.

BACKGROUND: A ΔFOSB mediated transcriptional response in the nucleus accumbens (NAc) is induced by chronic social stress in rodent and a 50% down-regulation of ΔFOSB has been also reported in the NAc of eight depressed subjects. To evaluate the role of ΔFOSB in the prefrontal cortex which is critically involved in negative cognitive bias associated with major depressive disorder (MDD) we have quantified the mRNA levels of ΔFOSB and of five of its major target genes in the Brodmann area 46 from 24 patients with MDD (11 with psychotic symptoms) and 12 controls. METHOD: Expression of the six genes has been quantified by a real-time quantitative PCR method: ΔFOSB, GRIA2 (encoding the GluR2 subunit of the AMPA receptor), SPARCL1 (encoding hevin), SG3 (encoding the secretogranin III), PCP4 (encoding the Purkinje cell protein 4), ATP6V0C (encoding a subunit of the lysosomal ATPase). RESULTS: Expression of ΔFOSB and GRIA2 was significantly up-regulated (≈ 1.60) in the BA 46 of MDD patients. Overexpression of SCG3 and PCP4 was restricted to psychotic subjects. The mRNA levels of GRIA2, SCG3 and PCP4 were strongly correlated in the depressed group. LIMITATIONS: All the patients were treated by antidepressants and the number of subjects in each subgroup was rather small. CONCLUSIONS: Induction of a ΔFOSB mediated transcriptional pattern in the prefrontal cortex is opposite to the down-regulation observed in the NAc. The major consequence might be a shift in the excitability of the glutamatergic synapses which depends on GluR2 (high in the NAc and low in the BA 46).

Expression of oxidative stress-response genes is not activated in the prefrontal cortex of patients with depressive disorder.

To test the hypothesis that the oxidative stress consistently detected in the peripheral blood of patients with depressive disorder impacts on the functionally relevant brain region, the expression level of nine major genes of the stress response and repair systems has been quantified in the prefrontal cortex of 24 depressive and 12 control subjects. These genes were: superoxide dismutase (SOD1), SOD2, catalase (CAT), gluthatione peroxidase 1 (GPx1), 8-oxoguanine DNA glycosylase (OGG1), nei-like 1 (NEIL1), methionine sulphoxide reductase A (MSRA), telomere repeat-binding factor 2 (TERF2) and C-FOS. Telomere length (a maker of chronic exposure to oxidative stress) has been measured in the DNA of the occipital cortex. No significant difference has been found between the compared groups. It must be concluded that the pathogenic role of the oxidative stress in the cerebral mechanism of depression cannot be inferred from the alteration of peripheral parameters.

Telomere length and cardiovascular disease.

Telomeres are structures composed of deoxyribonucleic acid repeats that protect the end of chromosomes, but shorten with each cell division. They have been the subject of many studies, particularly in the field of oncology, and more recently their role in the onset, development and prognosis of cardiovascular disease has generated considerable interest. It has already been shown that these structures may deteriorate at the beginning of the atherosclerotic process, in the onset and development of arterial hypertension or during myocardial infarction, in which their length may be a predictor of outcome. As telomere length by its nature is a marker of cell senescence, it is of particular interest when studying the lifespan and fate of endothelial cells and cardiomyocytes, especially so because telomere length seems to be regulated by various factors notably certain cardiovascular risk factors, such as smoking, sex and obesity that are associated with high levels of oxidative stress. To gain insights into the links between telomere length and cardiovascular disease, and to assess the usefulness of telomere length as a new marker of cardiovascular risk, it seems essential to review the considerable amount of data published recently on the subject.

Search for the best indicators for the presence of a VPS13B gene mutation and confirmation of diagnostic criteria in a series of 34 patients genotyped for suspected Cohen syndrome.

BACKGROUND: Cohen syndrome is a rare autosomal recessive inherited disorder that results from mutations of the VPS13B gene. Clinical features consist of a combination of mental retardation, facial dysmorphism, postnatal microcephaly, truncal obesity, slender extremities, joint hyperextensibility, myopia, progressive chorioretinal dystrophy, and intermittent neutropenia. PATIENTS AND METHODS: The aim of the study was to determine which of the above clinical features were the best indicators for the presence of VPS13B gene mutations in a series of 34 patients with suspected Cohen syndrome referred for molecular analysis of VPS13B. RESULTS: 14 VPS13B gene mutations were identified in 12 patients, and no mutation was found in 22 patients. The presence of chorioretinal dystrophy (92% vs 32%, p=0.0023), intermittent neutropenia (92% vs 5%, p<0.001), and postnatal microcephaly (100% vs 48%, p=0.0045) was significantly higher in the group of patients with a VPS13B gene mutation compared to the group of patients without a mutation. All patients with VPS13B mutations had chorioretinal dystrophy and/or intermittent neutropenia. The Kolehmainen diagnostic criteria provided 100% sensibility and 77% specificity when applied to this series. CONCLUSION: From this study and a review of more than 160 genotyped cases from the literature, it is concluded that, given the large size of the gene, VPS13B screening is not indicated in the absence of chorioretinal dystrophy or neutropenia in patients aged over 5 years. The follow-up of young patients could be a satisfactory alternative unless there are some reproductive issues.

Genomic deletions of OFD1 account for 23% of oral-facial-digital type 1 syndrome after negative DNA sequencing.

Oral-facial-digital type I syndrome (OFDI) is characterised by an X-linked dominant mode of inheritance with lethality in males. Clinical features include facial dysmorphism with oral, dental and distal abnormalities, polycystic kidney disease and central nervous system malformations. Considerable allelic heterogeneity has been reported within the OFD1 gene, but DNA bi-directional sequencing of the exons and intron-exon boundaries of the OFD1 gene remains negative in more than 20% of cases. We hypothesized that genomic rearrangements could account for the majority of the remaining undiagnosed cases. Thus, we took advantage of two independent available series of patients with OFDI syndrome and negative DNA bi-directional sequencing of the exons and intron-exon boundaries of the OFD1 gene from two different European labs: 13/36 cases from the French lab; 13/95 from the Italian lab. All patients were screened by a semiquantitative fluorescent multiplex method (QFMPSF) and relative quantification by real-time PCR (qPCR). Six OFD1 genomic deletions (exon 5, exons 1-8, exons 1-14, exons 10-11, exons 13-23 and exon 17) were identified, accounting for 5% of OFDI patients and for 23% of patients with negative mutation screening by DNA sequencing. The association of DNA direct sequencing, QFMPSF and qPCR detects OFD1 alteration in up to 85% of patients with a phenotype suggestive of OFDI syndrome. Given the average percentage of large genomic rearrangements (5%), we suggest that dosage methods should be performed in addition to DNA direct sequencing analysis to exclude the involvement of the OFD1 transcript when there are genetic counselling issues.

The activation pattern of the antioxidant enzymes in the right ventricle of rat in response to pressure overload is of heart failure type.

In the left ventricle subjected to pressure overload activity, the antioxidant enzymes increased at the hyperfunctional stage. During the transition to heart failure, these enzymes are down-regulated, oxidative stress increases, and apoptosis progresses. Maladaptative activation of the antioxidant enzymes at an early stage may contribute to the intrinsic vulnerability of right ventricle to pressure overload. The authors studied changes in expression and activity of the enzymes manganese and copper-zinc superoxide dismutases, glutathione peroxidase, and catalase in the right ventricle of rat following induction of pulmonary hypertension by injection of monocrotaline. Increase in the manganese superoxide dismutase was delayed to the late failing stage, activity of glutathione peroxidase was depressed throughout, and only catalase was activated at the early stage before returning to control levels. This inability to activate antioxidant enzymes may contribute to the deleterious consequences of pressure overload on right ventricle systolic function.