The effect of childhood trauma and trauma-focused psychotherapy on blood expression of MED22 in patients with major depressive disorder

Introduction

The only available genome-wide study (Minelli et al., 2018) indicated an association between the neglect CT and MED22, a transcriptional factor gene.

Objectives

To verify how the dysregulation of MED22 could be affected by environmental and genetic factors, we carried out an analysis on these components and a longitudinal study concerning the effect of trauma-focused psychotherapy in MDD patients that experienced CT.

Methods

On a large mRNA sequencing dataset including 368 MDD patients we computed the genetic (GReX) and the environmental (EReX) components affecting gene expression in relation to CT. Furthermore, we measured the expression of MED22 in 22 MDD patients treated with trauma-focused psychotherapy.

Results

The dissection of MED22 expression profiles revealed an association of neglect with environmental and genetic components (p=6x10^-3 p=2.6x10^-4). Furthermore, in an independent cohort of 177 controls, we also observed a significant association between cis-eSNPs of MED22 and higher neuroticism scores (best p-value: 0.00848) that are usually associated with a decreased amount of resilience to stress events. Finally, the results of psychotherapy revealed a reduction of depressive symptomatology (p<0.001) and 73% of patients resulted responders at the follow-up visit. MED22 expression during psychotherapy showed a change trend (p=0.057) with an interaction effect with response (p=0.035). Responder and non-responder patients showed MED22 expression differences at different trauma-focused psychotherapy timepoints (p=0.15; p=0.012) and at the follow-up (p=0.021).

Conclusions

Our results provide insights suggesting that some biological and clinical consequences of CT depend on genetic background and environmental factors that could induce vulnerability or resilience to stressful life events.

Disclosure

No significant relationships.

What is the genetic architecture of major psychiatric disorders?

Taken as a whole, psychiatric disorders are considered as complex genetic disorders. There are clear genetic mutations and susceptibility factors to these disorders. However, these form the full spectrum of impact, frequency, and mutation type. With rare large scale chromosomal rearrangements and copy number mutations of high impact at one end, and common single nucleotide variations of minor impact at the other. This multitude of variation type also means that different epidemiological study designs are needed to test the genetic component of these disorders, from familial forms, to common population level studies. This process has been facilitated by advances in genomic analysis, that enable the measuring of genetic variation at a greater depth in a greater number of individuals and has led to a boom in genetic information. This has given us a greater understanding of the genetic aetiology of psychiatric disorders and how they are biologically related to each other. How this information can be translated to the clinics, can now be considered. Genetic testing in psychiatric disorders, is currently possible for certain disorders and mutation types, but is not universally advised. Much still remains to be understood about population level genetic risk factors before they could conceivably be utilised in the clinic. Whereas genetic testing of high impact mutations could be of use to the clinical programs, and are actively tested for in clinics across Europe.

The effect of childhood trauma and trauma-focused psychotherapy on blood expression in patients with major depressive disorder

The only available genome-wide study (Minelli et al., 2018) indicated an association between the neglect CT and MED22, a transcriptional factor gene. To verify how the dysregulation of MED22 could be affected by environmental and genetic factors, we carried out an analysis on these components and a longitudinal study concerning the effect of trauma-focused psychotherapy in MDD patients that experienced CT. On a large mRNA sequencing dataset including 368 MDD patients we computed the genetic (GReX) and the environmental (EReX) components affecting gene expression in relation to CT. Furthermore, we measured the expression of MED22 in 22 MDD patients treated with trauma-focused psychotherapy. The dissection of MED22 expression profiles revealed an association of neglect with environmental and genetic components (p=6x10^-3 p=2.6x10^-4). Furthermore, in an independent cohort of 177 controls, we also observed a significant association between cis-eSNPs of MED22 and higher neuroticism scores (best p-value: 0.00848) that are usually associated with a decreased amount of resilience to stress events. Finally, the results of psychotherapy revealed a reduction of depressive symptomatology (p<0.001) and 73% of patients resulted responders at the follow-up visit. MED22 expression during psychotherapy showed a change trend (p=0.057) with an interaction effect with response (p=0.035). Responder and non-responder patients showed MED22 expression differences at different trauma-focused psychotherapy timepoints (p=0.15; p=0.012) and at the follow-up (p=0.021). Our results provide insights suggesting that some biological and clinical consequences of CT depend on genetic background and environmental factors that could induce vulnerability or resilience to stressful life events.

Proteasome system dysregulation and treatment resistance mechanisms in major depressive disorder

Several studies have demonstrated that allelic variants related to inflammation and the immune system may increase the risk for major depressive disorder (MDD) and reduce patient responsiveness to antidepressant treatment. Proteasomes are fundamental complexes that contribute to the regulation of T-cell function. Only one study has shown a putative role of proteasomal PSMA7, PSMD9 and PSMD13 genes in the susceptibility to an antidepressant response, and sparse data are available regarding the potential alterations in proteasome expression in psychiatric disorders such as MDD. The aim of this study was to clarify the role of these genes in the mechanisms underlying the response/resistance to MDD treatment. We performed a case-control association study on 621 MDD patients, of whom 390 were classified as treatment-resistant depression (TRD), and we collected peripheral blood cells and fibroblasts for mRNA expression analyses. The analyses showed that subjects carrying the homozygous GG genotype of PSMD13 rs3817629 had a twofold greater risk of developing TRD and exhibited a lower PSMD13 mRNA level in fibroblasts than subjects carrying the A allele. In addition, we found a positive association between PSMD9 rs1043307 and the presence of anxiety disorders in comorbidity with MDD, although this result was not significant following correction for multiple comparisons. In conclusion, by confirming the involvement of PSMD13 in the MDD treatment response, our data corroborate the hypothesis that the dysregulation of the complex responsible for the degradation of intracellular proteins and potentially controlling autoimmunity- and immune tolerance-related processes may be involved in several phenotypes, including the TRD.

Association between baseline serum vascular endothelial growth factor levels and response to electroconvulsive therapy

OBJECTIVE

Several studies have shown that vascular endothelial growth factor (VEGF) is implicated in different neuronal processes involved in major depressive disorder (MDD) and in the mechanisms of action of antidepressants. The aim of this study was to investigate whether VEGF serum levels before treatment might be associated with the antidepressant response.

METHOD

Two groups of patients were enrolled. One was composed of 50 MDD patients receiving an antidepressant drug treatment. Illness severity was measured before the treatment (T0) and after 12 weeks (T1). The second group was composed of 67 treatment-resistant depressed (TRD) patients undergoing electroconvulsive therapy (ECT). Illness severity was assessed before the treatment (T0) and 1 month after the end of ECT (T1). Blood samples for VEGF measurements were collected for both groups at the baseline (T0).

RESULTS

A significant correlation was observed between baseline VEGF serum levels and the percentage reduction in depressive symptomatology after ECT (P = 0.003). In particular, VEGF levels at baseline were significantly lower in patients showing no response to ECT at follow-up (P = 0.008). No correlation between T0 VEGF concentrations and drug treatment outcome was found.

CONCLUSION

Our results suggest that VEGF plays a role in the mechanism of response to ECT.

Genetic background predicts poor prognosis in frontotemporal lobar degeneration

BACKGROUND

Ruling out predictors of survival in frontotemporal lobar degeneration (FTLD) is a clinical challenge for defining disease outcomes and monitoring therapeutic interventions. Little is known about determinants of survival in FTLD.

OBJECTIVE

The aim of the present study was to identify whether genetic determinants are key, not only as risk factors but as predictors of survival in FTLD.

METHODS

Ninety-seven FTLD patients were considered in the present study. A clinical evaluation and a standardized assessment were carried out. Each patient underwent blood sampling for genetic testing, and mutations within the progranulin (PGRN) gene, microtubule-associated protein tau (MAPT) haplotype, apolipoprotein E (APOE) genotype and 4 vascular endothelial growth factor (VEGF) polymorphisms were evaluated. Discrete-time survival models were applied.

RESULTS

Monogenic FTLD due to PGRN mutations [odds ratio (OR) = 3.62, 95% confidence interval (CI) = 1.12-11.7; p = 0.032], and MAPT *H2 haplotype (OR = 3.23, 95% CI = 1.08-9.69; p = 0.036) were associated with an increased hazard risk of poor outcome. Conversely, APOE genotype, and VEGF polymorphisms were not associated with survival risk in the FTLD sample.

CONCLUSIONS

Genetic background is not only crucial in disease pathogenesis, but it also modulates disease course. Genetic factors influencing prognosis should be taken into account to include homogeneous groups in future clinical trials and to monitor efficacy of future interventions.

Genome-wide association study of increasing suicidal ideation during antidepressant treatment in the GENDEP project

Suicidal thoughts during antidepressant treatment have been the focus of several candidate gene association studies. The aim of the present genome-wide association study was to identify additional genetic variants involved in increasing suicidal ideation during escitalopram and nortriptyline treatment. A total of 706 adult participants of European ancestry, treated for major depression with escitalopram or nortriptyline over 12 weeks in the Genome-Based Therapeutic Drugs for Depression (GENDEP) study were genotyped with Illumina Human 610-Quad Beadchips (Illumina, San Diego, CA, USA). A total of 244 subjects experienced an increase in suicidal ideation during follow-up. The genetic marker most significantly associated with increasing suicidality (8.28 × 10(-7)) was a single-nucleotide polymorphism (SNP; rs11143230) located 30 kb downstream of a gene encoding guanine deaminase (GDA) on chromosome 9q21.13. Two suggestive drug-specific associations within KCNIP4 (Kv channel-interacting protein 4; chromosome 4p15.31) and near ELP3 (elongation protein 3 homolog; chromosome 8p21.1) were found in subjects treated with escitalopram. Suggestive drug by gene interactions for two SNPs near structural variants on chromosome 4q12, one SNP in the apolipoprotein O (APOO) gene on chromosome Xp22.11 and one on chromosome 11q24.3 were found. The most significant association within a set of 33 candidate genes was in the neurotrophic tyrosine kinase receptor type 2 (NTRK2) gene. Finally, we also found trend for an association within genes previously associated with psychiatric phenotypes indirectly linked to suicidal behavior, that is, GRIP1, NXPH1 and ANK3. The results suggest novel pathways involved in increasing suicidal ideation during antidepressant treatment and should help to target treatment to reduce the risk of this dramatic adverse event. Limited power precludes definitive conclusions and replication in larger sample is warranted.

TARDBP mutations in frontotemporal lobar degeneration: frequency, clinical features, and disease course

The 43-kD transactive response (TAR)-DNA-binding protein (TARDBP) mutations have been demonstrated to be causative of sporadic and familial forms of amyotrophic lateral sclerosis. More recently, these mutations have been reported in cases of frontotemporal lobar degeneration (FTLD). The aim of this study was to evaluate the role of TARDBP genetic variations in a large sample of consecutive patients with FTLD. A total of 252 FTLD patients were investigated. Each subject had a clinical and neuropsychological evaluation and a brain imaging study. The clinical diagnosis was confirmed by at least 1 year of follow up. The entire TARDBP gene, the intronic flaking regions, and the 5'-untranslated region (5'-UTR) were screened. Six genetic variations were identified in patients with behavioral variant frontotemporal dementia (FTD) and FTD with motor neuron disease phenotypes. Two of these mutations, namely N267S and M359V, lead to amino acid changes within exon 6. We further identified three genetic variations, i.e., Y214Y, IVS-IV + 45C/T, and 5'-UTR G/A, that could potentially affect the normal splicing process as predicted by in silico analyses. None of these genetic variations was found in healthy age-matched controls. Moreover, we identified a previously described benign variant, A66A, in 5 patients. Our study has confirmed and extended the list of pathogenetic mutations in the TARDBP gene in both apparently sporadic and familial FTLD patients. This work further supports the need for TARDBP screening in FTLD. Also intronic splicing that affects mutations should be considered as well.

Genotyping of spinal muscular atrophy families with linked DNA probes

We report on linkage analysis and haplotype characterization in 40 Italian families with spinal muscular atrophy (SMA). The investigated loci included D5S6, D5S112, D5S39, and D5S76. No evidence of unlinked families was found. Thirty-two (80%) of the examined families were fully informative for prenatal diagnosis and carrier detection. The frequencies of individual alleles did not differ between SMA and normal chromosomes.

Serum leptin levels are higher in females affected by frontotemporal lobar degeneration than Alzheimer's disease

Frontotemporal lobar degeneration (FTLD) includes different heterogeneous conditions, mainly characterised by personality changes, along with cognitive deficits in language and executive functions. Movement disorders are variably represented. Behavioural disturbances constitute the core feature of FTLD, and eating disorders represent one of the most distinguishing symptoms between FTLD and Alzheimer's disease (AD). The biochemical correlates of such dysfunctions remain to be defined. The adipocyte derived hormone leptin is known to play a foundamental role in food intake and energy balance. To understand whether leptin could be involved in FTLD eating abnormalities, we measured serum leptin levels in 59 patients with FTLD compared with 25 with AD. Serum leptin levels in patients with FTLD were comparable with those in patients with AD. Nevertheless, females with FTLD showed significantly higher leptin levels compared with females with AD. No difference was found between FTDL and AD males or within the spectrum of patients with FTLD. Hyperphagic FTLD females showed higher circulating leptin levels in comparison with those without eating abnormalities; no differences were found between males with FTLD with respect to serum leptin and food intake disturbances. The present study showed a selective gender difference in leptin levels between females with FTLD and AD, which may suggest specific cognitive and behavioural networks need to be investigated.

Dementia, delusions and seizures: storage disease or genetic AD?

We describe a case of a young patient suffering from a rapidly progressive cognitive decline, associated with delusions, myoclonus and seizures and with no family history for dementia. Clinical features, along with skin biopsy findings were overlapping storage disease; the genetic analysis, however, demonstrated a de novo presenilin 1 mutation. The present report suggests the usefulness of genetic determinations in early-onset cases of dementia, even without an autosomal dominant trait of inheritance; for these cases and their relatives an extensive genetic counselling should be recommended.

No evidence for allelic association of serotonin 2A receptor and transporter gene polymorphisms with depression in Alzheimer disease

Patients with Alzheimer disease (AD) often exhibit psychiatric symptoms associated with cognitive impairment. The serotoninergic system may be involved in the development of depressive symptoms in AD patients, as suggested by the evidence that antidepressant drugs having the serotonin transporter as their target are effectively used to treat depressive AD patients. The aim of this study was to investigate the role of serotonin in depression, searching for association of two serotoninergic polymorphisms (T102C of serotonin receptor 5-HT2A and serotonin transporter linked polymorphic region -5-HTTLPR- of SLC6A4 gene) with depressive symptoms and considering their possible interactions with Apolipoprotein E (ApoE) and between themselves, in a sample of 208 sporadic AD patients and 116 normal controls from Italy. 5-HTTLPR and T102C are not associated with AD when separately analysed. However, we found out an interaction between the two polymorphisms in L/L and C/C genotype carriers increasing the risk for the disease (p=0.015, OR=8.048; 95% CI: 1.497-43.262). No association of the polymorphisms was detected with depression linked to AD. No interaction between 5-HTTLPR and T102C was detected in depressive AD subjects, even after stratification according to the presence of ApoE4 allele. These results suggest that the serotoninergic system may be not involved in the pathogenesis of depressive symptoms in AD patients, and it may be involved in other aspects of disease pathophysiology like cognitive symptoms and psychosis.

Italian guidelines for molecular analysis in myotonic dystrophies

Myotonic dystrophies, the most common form of adult muscular dystrophy, comprise at least two forms, clinically and genetically heterogeneous. Myotonic dystrophy type 1 and type 2 are both caused by unstable repetitions in untranslated gene regions: a [CTG]n expansion in the 3' region of the DMPK gene on chromosome 19q13 (DM1) and [CCTG]n tetranucleotide repeat located in the first intron of the ZNF9 gene on chromosome 3q21 (DM2). DM clinical features are caused by a gain of functions RNA mechanism in which the CUG and CCUG repeats alter nuclear functions, including alternative splicing of shared genes. Southern blot and/or polymerase chain reaction PCR-based approaches allow the detection of DM mutations in almost 100% of cases, however, the expansion size and the elevated grade of somatic instability make molecular testing for DM a diagnostic challenge. The increased use of DNA testing for DM generates many questions regarding the indications and interpretations of the test which require standardized methods, routinely available in molecular genetic laboratories. Here, we propose Guidelines for the molecular diagnosis of DM1 and DM2 approved by the Italian Ministry of Health in 2005 (Piano Nazionale Linee Guida, PNLG). Best practice for DM molecular analysis in diagnostic application, presymptomatic and prenatal testing, using direct and indirect approaches are described, with particular attention focused on ethical, legal and social issues. Overviews of materials used in the molecular diagnosis, as well as internet resources, are also included.

Repetitive transcranial magnetic stimulation (rTMS) at high and low frequency: an efficacious therapy for major drug-resistant depression?

OBJECTIVE

Repetitive transcranial magnetic stimulation (rTMS) is proposed for the treatment of drug-resistant depression. Studies performed in accordance with evidence-based medicine (EBM) are scarce, particularly in seeking optimal treatment and evaluation parameters. We aimed to test various types of rTMS in a large sample of depressed patients following EBM rules and to investigate treatment-related changes in plasma levels of neurotransmitters involved in depression.

METHODS

Seventy-one drug-resistant depressed patients were randomly assigned to low (1 Hz) or high (17 Hz) rate TMS, applied for 5 days over the left dorsolateral prefrontal cortex (L-DLPFC). Patients were separated into two study designs. One group (20 patients) received only active treatment, while the other entered a double-blind, placebo-controlled, crossover design. Pre- and post-treatment blood samples were taken for evaluation of plasma levels of dopamine and serotonin.

RESULTS

After a week of treatment patients had a measurable benefit. However, overall the placebo stimulation did not differ significantly from real stimulation, nor were differences observed between the two rates of rTMS. The only difference emerged when the real stimulation was applied at 17 Hz following placebo treatment. Plasma levels of neurotransmitters between active and placebo rTMS were similar.

CONCLUSIONS

Using the treatment schedule of 1 week, although a clinical improvement after active treatment was indeed observed, this was both clinically and biochemically indistinguishable from that seen in the placebo arm.

SIGNIFICANCE

This suggests that most of the previous emphasis, for short period of treatment, should be tempered down and that further work is required in order to verify whether optimal stimulation and evaluation parameters for TMS-treatment of depression beyond the placebo effect may be found following EBM rules.

Cytokine gene polymorphisms in gastric cancer patients from two Italian areas at high and low cancer prevalence

Polymorphisms of interleukin-1beta (IL-1beta), IL-1 receptor antagonist (IL1-RN), and tumor necrosis factor-alpha (TNF-alpha) genes are supposed to be key determinants of gastric cancer risk. Our aim was to study the association between these polymorphisms and gastric cancer in two areas characterized by high (Pavia/Bologna, North Italy) and low (San Giovanni Rotondo, South Italy) gastric cancer prevalence. Genomic DNA was obtained from 216 healthy donors and 98 gastric cancer patients from Pavia and Bologna, and 146 healthy donors and 86 gastric cancer patients from San Giovanni Rotondo. Two SNP in IL-1beta (-511 C/T) and TNF-alpha (-308 G/A) as well as the VNTR polymorphism of IL-1RN locus were studied. A significant linkage disequilibrium was found between IL-1beta -511 and IL-1RN. Genotype and allele frequencies at the IL-1beta, IL-1RN, and TNF-alpha loci in gastric cancer cases were not significantly different from controls. An epistatic effect between IL-1beta -511 and IL-1RN was found with the IL-1beta -511C/IL-1RN*2 haplotype conferring a significant protection against the intestinal-type of gastric cancer in the Southern population. In conclusion, IL-1beta, IL1-RN, and TNF-alpha genotypes are not associated with gastric cancer in Italian patients. An epistatic interrelationship between IL-1beta -511 and IL-1RN confers protection against gastric cancer in low-risk Italian population.

Allelic variation in the human prodynorphin gene promoter and schizophrenia

Experimental and clinical studies suggest an involvement of the opioid neuropeptide system in schizophrenia. In particular, the prodynorphin (PDYN), the precursor of the dynorphin opioid peptides, has been shown to play an important role in several aspects of human mental diseases. Recently, a functional polymorphism in the promoter of PDYN gene has been described. We studied the possible relationship between this polymorphism and schizophrenia and we found no significant difference in allelic and genotype distributions between schizophrenic patients and control subjects. However, we observed a significant interactive effect with the receptor 3 of dopamine gene (DRD3); in particular, the frequency of subjects carrying PDYN allele 3 being also homozygotes for DRD3 Gly allele (of Ser9Gly polymorphism) was significantly greater in patients than controls. We conclude that PDYN gene polymorphism alone does not alter the risk for schizophrenia but, by an epistatic interaction with the Gly allele of DRD3 gene, may contribute to the susceptibility to this disorder.

Epidemiology of myotonic dystrophy in Italy: re-apprisal after genetic diagnosis

Before the discovery of the myotonic dystrophy (DM) gene, the DM epidemiological rates could not be accurately estimated. The aim of this study was to calculate the DM prevalence rates in Padova (North-East Italy) and in four provinces of North-West Tuscany (Central Italy) and, as of 30 June 1999, to do so using molecular genetic testing. A minimum prevalence rate of 9.31x10(-5) inhabitants was found, consistent with epidemiological rates worldwide, and more than two times as high as those of two previous studies conducted in the same areas during the era prior to molecular genetic testing. This study, the first in Italy since the discovery of the DM gene, underlines the importance of direct genetic diagnosis of DM, especially in detecting mildly affected patients, a fundamental step in correctly estimating the risk of disease transmission in affected families.

Association between the ionotropic glutamate receptor kainate 3 (GRIK3) ser310ala polymorphism and schizophrenia

Schizophrenia is a severe psychiatric illness characterised by disturbance of thought, hallucination and delusions.(1) Several studies have suggested that dysfunctions in the glutamatergic transmission are linked to the pathogenesis of schizophrenia, and in particular an excessive activation of glutamate receptors seems to be related to the disruption of neuronal ionic gradients leading to excitotoxicity.(2-7) Numerous findings suggested that the kainate ionotropic glutamate receptors are primarily involved in this mechanism. Recently it has been demonstrated that the GRIK3 gene encoding for the ionotropic glutamate receptor kainate 3 contains a functional polymorphism (T928G) leading to the substitution of a serine with an alanine in position 310 of the protein sequence.(8-11) We performed an association study between the ser310ala GRIK3polymorphism and schizophrenia in a sample of 99 schizophrenic patients and 116 controls. We found a significant difference in the genotype distribution and in particular considering the ala allele as dominant (P = 0.0105, odds ratio (OR) 2.031, 95% confidence interval (CI) 1.177-3.504). This finding suggests a potential role for GRIK3 for susceptibility to schizophrenia.

Combined alpha 2-adrenergic/D2 dopamine receptor blockade fails to reproduce the ability of clozapine to reverse phencyclidine-induced deficits in prepulse inhibition of startle

RATIONALE

The combination of idazoxan, a specific alpha(2)-adrenoceptor antagonist with raclopride, a selective D(2)/D(3) receptor antagonist, has been recently proposed to produce an "atypical" antipsychotic profile comparable to that of clozapine, based on an animal study which analysed dopamine efflux in the medial prefrontal cortex and the preclinical test of conditioned avoidance response (CAR) for evaluation of antipsychotic potential. Accordingly, the combination of a "typical" antipsychotic with idazoxan has been proposed as an augmentation strategy in treatment-resistant schizophrenia, although its therapeutic potential remains difficult to predict.

OBJECTIVES

Given the momentum stimulated by these reports, the present study investigated whether the combination of idazoxan with raclopride is indeed sufficient to mimic the ability of clozapine to reverse prepulse inhibition (PPI) deficits in rats, a behavioral paradigm that models PPI deficits observed in the schizophrenia spectrum, and currently the only test which reliably appears to distinguish between "typical" antipsychotics and compounds with "atypical" antipsychotic potential.

METHODS

The effects of the combination idazoxan/raclopride were examined in two PPI paradigms: 1) phencyclidine (PCP)-induced disruption of PPI, which has been shown to be preferentially reversed by "atypical" antipsychotics; 2) apomorphine-induced disruption of PPI which can be reversed by either "typical" high-potency D(2) dopamine antagonists or "atypical" antipsychotics.

RESULTS

In contrast to clozapine, combining idazoxan with raclopride failed to reverse PCP-induced deficits in PPI. In addition, there was no evidence of an enhancing effect of idazoxan on the blockade of apomorphine-induced disruption of PPI by raclopride.

CONCLUSION

The present results challenge the hypothesis that simple alpha(2)/D(2) blockade is sufficient to produce clozapine-like "atypical" antipsychotic activities, and support the consensus that the PPI paradigm represents the most sophisticated behavioral preclinical test for detecting selective "atypical" profile of antipsychotics.

Modulation of fibroblast growth factor-2 by stress and corticosteroids: from developmental events to adult brain plasticity

Neurotrophic factors are a heterogeneous group of peptides that play important roles on brain function at different development stages. Basic fibroblast growth factor (FGF-2), one of these molecules, is highly expressed in developing and adult brain. Its expression can be regulated under different experimental situations and this may be relevant for cellular vulnerability and brain plasticity. Stress and glucocorticoid hormones produce short- and long-term effects on brain function, which can involve the regulation of specific neurotrophic factors within selected brain structures. Treatments with corticosterone or dexamethasone up-regulate FGF-2 expression in different rat brain regions as well as in cultured astroglial cells. A similar elevation of FGF-2 biosynthesis is also observed in several brain regions following an acute restraint stress. This response is rapid and transient and, as FGF-2 is neuroprotective, may represent a defense mechanism through which the brain may limit the deleterious effect of stress over time. Moreover exposure to corticosterone during late stage of embryonic life (E18-E20) produces a significant reduction of FGF-2 mRNA levels in the adult hippocampus of male rats as well as changes in its acute modulation in response to stress or corticosterone. These data suggest that stress-related events taking place during brain maturation can modulate the expression of FGF-2 within selected brain regions thus contributing to permanent structural and functional alterations leading to an increased vulnerability to challenging life events.

Human Y-chromosome variation in the western Mediterranean area: implications for the peopling of the region

Y-chromosome variation was analyzed in a sample of 1127 males from the Western Mediterranean area by surveying 16 biallelic and 4 multiallelic sites. Some populations from Northeastern Europe and the Middle East were also studied for comparison. All Y-chromosome haplotypes were included in a parsimonious genealogic tree consisting of 17 haplogroups, several of which displayed distinct geographic specificities. One of the haplogroups, HG9.2, has some features that are compatible with a spread into Europe from the Near East during the Neolithic period. However, the current distribution of this haplogroup would suggest that the Neolithic gene pool had a major impact in the eastern and central part of the Mediterranean basin, but very limited consequences in Iberia and Northwestern Europe. Two other haplogroups, HG25.2 and HG2.2, were found to have much more restricted geographic distributions. The first most likely originated in the Berbers within the last few thousand years, and allows the detection of gene flow to Iberia and Southern Europe. The latter haplogroup is common only in Sardinia, which confirms the genetic peculiarity and isolation of the Sardinians. Overall, this study demonstrates that the dissection of Y-chromosome variation into haplogroups with a more restricted geographic distribution can reveal important differences even between populations that live at short distances, and provides new clues to their past interactions.

Long-term treatment with S-adenosylmethionine induces changes in presynaptic CaM kinase II and synapsin I

BACKGROUND

According to current hypotheses, antidepressant drug action is the result of adaptive changes in neuronal signaling mechanisms rather than a primary effect on neurotransmitter transporters, receptors, or metabolic enzymes. Among the signaling mechanisms involved, protein kinases and phosphorylation have been shown to be modified by drug treatment. Presynaptic signaling (calcium/calmodulin-dependent protein kinase II [CaMKII]) and the protein machinery regulating transmitter release have been implicated in the action of these drugs.

METHODS

We investigated the effect of S-adenosylmethionine (SAM), a compound with putative antidepressant activity, on presynaptic CaMKII and its synaptic vesicle substrate synapsin I. The activity of CaMKII was assayed in synaptic subcellular fractions prepared from hippocampus (HI), frontal cortex (FCX), striatum (STR), and parieto-temporal cortex.

RESULTS

The kinase activity was increased after SAM treatment in the synaptic vesicle fraction of HI (31.7%), FCX (35.9%), and STR (18.4%). The protein level of CaMKII was also increased in synaptic vesicles of HI (40.4%). The synapsin I level was unchanged in synaptic vesicles but markedly increased in synaptic cytosol of HI (75.8%) and FCX (163.0%). No changes for both CaMKII and synapsin I level were found in homogenates, suggesting that synaptic protein changes are not explained by an increase in total level of proteins, but rather by translocation to nerve terminals.

CONCLUSIONS

Similar to typical antidepressant drugs, SAM induces changes in CaMKII activity and increases synapsin I level in HI and FCX nerve terminals, suggesting a modulatory action on transmitter release.

Modulation of glutamate receptors in response to the novel antipsychotic olanzapine in rats

BACKGROUND

A disturbance in glutamate neurotransmission has been hypothesized in schizophrenia. Hence, the beneficial effects of pharmacological treatment may be related to adaptive changes taking place in this neurotransmitter system.

METHODS

In this study, we investigated the modulation of ionotropic and metabotropic glutamate receptors in the rat brain following acute or chronic exposure to the novel antipsychotic olanzapine.

RESULTS

In accordance with the clear distinction between classical and atypical drugs, olanzapine did not alter glutamate receptor expression in striatum. Chronic, not acute, exposure to olanzapine was capable of up-regulating hippocampal mRNA levels for GluR-B and GluR-C, two alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid (AMPA)-forming subunits. This effect could be relevant for the improvement of schizophrenic alterations, which are thought to depend on dysfunction of the glutamatergic transmission within the hippocampal formation. We also found that the expression of group II glutamate metabotropic receptors was up-regulated in the frontal cortex after chronic exposure to clozapine, and to a lesser extent olanzapine, but not with haloperidol.

CONCLUSIONS

The adaptive mechanisms taking place in glutamatergic transmission might prove useful in ameliorating some of the dysfunction observed in the brain of schizophrenic patients.

Decreased hippocampal BDNF expression after acute systemic injection of quinpirole

We report that acute quinpirole injection reduces BDNF mRNA levels in the rat hippocampus both at 2 and 6 h after the administration. These results suggest that the neurotrophin expression may be inhibited by situations involving dopaminergic overactivity.

Serine/threonine kinases as molecular targets of antidepressants: implications for pharmacological treatment and pathophysiology of affective disorders

It is currently a widely accepted opinion that adaptive, plastic changes in the molecular and cellular components of neuronal signaling systems correlate with the effects on mood and cognition observed after long-term treatment with antidepressant drugs. Protein phosphorylation represents a key step for most signaling systems, and it is involved in the regulation of virtually all cellular functions. Two serine/threonine kinases, Ca2+ /calmodulin-dependent protein kinase II and cyclic AMP-dependent protein kinase, have been shown to be activated in the brain following antidepressant treatment. The changes in kinase activity are mirrored by changes in the phosphorylation of selected protein substrates in subcellular compartments (presynaptic terminals and microtubules), which, in turn, may contribute to the modulation of synaptic transmission observed with antidepressants. The molecular consequences of protein kinase activation may account for some of the alterations in neural function induced by antidepressants, and may suggest novel possible strategies of pharmacological intervention.

Stimulatory role of dopamine on fibroblast growth factor-2 expression in rat striatum

We have previously shown that systemic injection of (-)nicotine produces a selective up-regulation of fibroblast growth factor (FGF)-2 mRNA levels in rat striatum. Because (-)nicotine can increase striatal release of dopamine and glutamate, in the present study we have investigated the contribution of these neurotransmitters in the modulation of FGF-2 expression. We found that coinjection of dopaminergic D1 (SCH23390) or D2 (haloperidol) receptor antagonists prevents nicotine-induced elevation of FGF-2 expression. However, injection of the NMDA receptor antagonist MK-801 produced a significant increment of FGF-2 mRNA and protein levels in rat striatum similar to the effect produced by (-)nicotine alone. Interestingly this effect of MK-801 could also be prevented by D1 or D2 receptor antagonists, suggesting that an elevation of dopamine levels may be required for the regulation of the trophic molecule. Accordingly we found that the non-selective dopaminergic agonist apomorphine can similarly increase striatal FGF-2 mRNA levels. Despite the observation that both D1 and D2 receptors appear to contribute to the modulation of FGF-2 expression, only a direct activation of D2 receptors, through quinpirole administration, was able to mimic the effect of apomorphine. On the basis of FGF-2 neurotrophic activity, these results suggest that direct or indirect activation of dopaminergic system can be neuroprotective and might reduce cell vulnerability in degenerative disorders.

Association between -G308A tumor necrosis factor alpha gene polymorphism and schizophrenia

Dysregulation of the inflammatory response system has been linked to pathophysiology of schizophrenia. Evidence of immune activation has derived from the detection of abnormal levels of proinflammatory cytokines and their receptors in peripheral blood and cerebrospinal fluid from schizophrenic patients. Cytokines are involved in normal CNS development as well as in the pathogenesis of many neuro-psychiatric disorders, acting directly on neural cells or modulating neurotransmitter and neuropeptide systems. In particular tumor necrosis factor alpha (TNFalpha), depending on its concentration, can exert both neurotrophic and neurotoxic effects and influence neural cell growth and proliferation. Moreover, TNFalpha gene is located on the small arm of chromosome 6 (6p21.1-21.3), a locus associated with genetic susceptibility to schizophrenia. We studied the distribution of -G308A TNFalpha gene polymorphism in 84 schizophrenic patients and in 138 healthy volunteers. This biallelic base exchange polymorphism directly affects TNFalpha plasma levels. Frequency of the TNF2(A) allele is significantly increased in schizophrenic patients as compared to controls (P = 0.0042). Genotype distribution is also significantly different (P = 0.0024). TNF2 homozygotes are represented only in the patient group (P = 0.002). These data suggest a potential role of TNFalpha as a candidate gene for susceptibility to schizophrenia and suggest that immune dysregulation in schizophrenic patients could also have a genetic component.

Natural history of cardiac involvement in myotonic dystrophy: correlation with CTG repeats

The authors prospectively studied the natural course of cardiac involvement and its relationship to cytosine-thymine-guanine (CTG) expansion in 50 patients with myotonic dystrophy who were submitted to periodic cardiovascular EKG and EKG-Holter monitoring during a median follow-up of 56 months. Nineteen patients (38%) developed major EKG changes. CTG length was not correlated with the frequency of EKG abnormalities, but was inversely correlated with the age at onset of EKG abnormalities (p < 0.0001). CTG length influences the timing of cardiac complications in myotonic dystrophy.

A distinctive autosomal dominant vacuolar neuromyopathy linked to 19p13

OBJECTIVE

To characterize a kindred with a distinctive autosomal dominant neuromuscular disorder.

BACKGROUND

The authors studied a large Italian family affected by a progressive neuromyopathy. Ten individuals over three generations were affected. The disease was characterized by onset from the late teens to early 50s with distal leg weakness and atrophy, development of generalized muscle weakness with distal-to-proximal progression sparing facial and ocular muscles, dysphonia and dysphagia, pes cavus and areflexia, variable clinical expression ranging from subclinical myopathy to severely disabling weakness, and mixed neurogenic and myopathic abnormalities on electromyography.

METHODS

Morphologic, immunocytochemical, and ultrastructural studies were performed in muscle biopsies from three affected patients. A genomewide linkage analysis through the genotyping of 292 microsatellite markers spanning the 22 autosomes was undertaken to map the disorder segregating in this family.

RESULTS

All muscle biopsies showed variation of fiber size, panesterase-positive angular fibers, mild to severe fibrosis, and numerous "rimmed vacuoles." Electron microscopy failed to demonstrate the nuclear or cytoplasmic filamentous inclusions specific of inclusion-body myopathies and, accordingly, immunohistochemistry did not show any positivity with SMI-31 antibodies detecting hyperphosphorylated tau. Preliminary analysis of 292 microsatellite markers provided evidence for linkage to chromosome 19p13.

CONCLUSIONS

This distinctive autosomal dominant disorder is characterized by a vacuolar neuromyopathy. Localization to chromosome 19p13 will allow the genetic relationship between this disease and inherited myopathies with rimmed vacuoles, in particular autosomal dominant inclusion-body myopathies, to be defined.

Cognitive impairment and (CTG)n expansion in myotonic dystrophy patients

BACKGROUND

Myotonic dystrophy (DM) is a genetic multisystemic disease with muscular, endocrine, ocular, cardiac and cognitive impairment. The molecular basis of the disease has been identified in an unstable base triplet (CTG)n repeat located in the 3' untranslated region of the miotonin protein-kinase (MT-PK) gene on the long arm of chromosome 19. Cognitive impairment could be a direct expression of this genetic alteration at the central nervous system (CNS) level rather than a consequence of the neuromuscular impairment. To explore this hypothesis, we tested a group of genetically diagnosed, adult onset DM, of their nonaffected relatives (NAR), of patients with spinal muscle atrophy (SMA), and of normal controls using the Wechsler Adult Intelligence Scale (WAIS).

METHODS

Seventeen adult-onset DM patients, 9 NAR, 10 SMA patients and 20 unrelated normal controls (NC) were studied. Clinical, neuromuscular and neuropsychiatric evaluation, which included WAIS and the Schedule for Affective Disorders and Schizophrenia (SADS), were performed on the four groups. DM, NAR and NC were also assessed by a neurophysiological (P300) evaluation. A DNA analysis was performed in DM and in NAR to measure presence and magnitude of CTG expansion.

RESULTS

We found a statistically significant difference between verbal (p < .0003), nonverbal (p < .0001) and total (p < .0001) IQ of DM patients compared to IQs of NAR, SMA and NC. Seven out of 11 WAIS subtests were significantly and consistently lower in DM patients compared to SMA and/or NC. In DM patients there was a statistically significant negative correlation between nonverbal (r = -.68; p < .002) and total (r = .59; p < .01) IQ and (CTG)n. Patients with DM had a significantly lower P300 amplitude compared to NAR and NC.

CONCLUSIONS

Our study indicates that in DM there is a mild but significant cognitive impairment which correlates with the degree of CTG expansion and it is not dependent on the neuromuscular impairment; however further studies with larger groups of patients and controls are suggested to confirm our results, due to the small sample size and to a possible effect of educational level in our patients.

CTG repeats distribution and Alu insertion polymorphism at myotonic dystrophy (DM) gene in Amhara and Oromo populations of Ethiopia

Myotonic dystrophy (DM) is a dominantly inherited neuromuscular disease, highly variable and multisystemic, which is caused by the expansion of a CTG repeat located in the 3' untranslated region of the DMPK gene. Normal alleles show a copy number of 5-37 repeats on normal chromosomes, amplified to 50-3000 copies on DM chromosomes. The trinucleotide repeat shows a trimodal allele distribution in the majority of the examined population. The first class includes alleles carrying (CTG)5, the second class, alleles in the range 7-18 repeats, and the third class, alleles (CTG) > or =19. The frequency of this third class is directly related to the prevalence of DM in different populations, suggesting that normal large-sized alleles predispose toward DM. We studied CTG repeat allele distribution and Alu insertion and/or deletion polymorphism at the myotonic dystrophy locus in two major Ethiopian populations, the Amhara and Oromo. CTG allele distribution and haplotype analysis on a total of 224 normal chromosomes showed significant differences between the two ethnic groups. These differences have a bearing on the out-of-Africa hypothesis for the origin of the DM mutation. In addition, (CTG) > or =19 were exclusively detected in the Amhara population, confirming the predisposing role of these alleles compared with the DM expansion-mutation.

Reduction of the DM-associated homeo domain protein (DMAHP) mRNA in different brain areas of myotonic dystrophy patients

Myotonic dystrophy (DM) is a multisystemic disease caused by expansion of a CTG trinucleotide repeat in the 3' untranslated region of the DMPK protein kinase gene on chromosome 19q13.3. The mechanism by which this expansion causes disease remains unknown. It has been suggested that CTG expansion not only affects the expression of the DMPK gene, but also alters the nuclear RNA metabolism and expression of neighboring genes. DMAHP, which is expressed in various human tissues, including skeletal muscle, heart and brain, is immediately distal to the 3' end of DMPK gene, in a CpG island which contains the CTG repeat. Here we report a 4- to 5-fold reduction of the expression of the DMAHP gene in different brain areas of DM patients. Our results demonstrate that [CTG]n expansion alters the brain DMAHP mRNA expression supporting a dominant-negative effect at the cellular level of DM [CTG]n mutation. The reduced brain expression of DMAHP could explain cerebral impairment in DM patients.

Myotonic dystrophy: tissue-specific effect of somatic CTG expansions on allele-specific DMAHP/SIX5 expression

Myotonic dystrophy (DM), the most common inherited muscle disorder, is caused by a CTG expansion in the 3"-untranslated region of a protein kinase gene ( DMPK ). The complex and variable phenotype is most likely caused by a complex molecular pathogenesis, including deficiency of the DMPK protein, a trans -dominant misregulation of RNA homeostasis and haploinsufficiency of a neighboring homeobox gene [DM locus-associated homeodomain protein (DMAHP )]. Here, we study the allele-specific transcriptional activity of the DMAHP/SIX5 gene in DM patient tissues. Using a quantitative fluorescent RT-PCR assay, we tested allele-specific accumulation of DMAHP/SIX5 transcripts in both total and poly(A)+pools. In muscle biopsies, we found that transcript reductions of DMAHP/SIX5 alleles in cis with CTG expansions correlated with the extent of expansion. A patient with approximately 90 CTG repeats in muscle DNA (normal n < 37) showed a 20% reduction of allele-specific transcript levels, while four other DM patients with larger expansions showed 80% reductions. The effects of the CTG expansions on DMAHP transcription were tissue specific: autopsy tissues from a patient with 1500 repeats showed 80% reductions in muscle and liver; however, RNA from other tissues (lung, aorta, heart conduction tissue, cerebellum) showed 0-20% reductions. Our results suggest that the effect of the CTG repeat on the DMAHP/SIX5 promoter is variable and tissue-specific. Our data are consistent with abnormalities of DMAHP/SIX5 probably having a more prominent role in disease pathogenesis in muscle, liver and brain, but being less important in other tissues.

A single polymerase chain reaction-based protocol for detecting normal and expanded alleles in myotonic dystrophy

The myotonic dystrophy (DM) expansion varies from 50 to 4000 CTG repeats in the 3' untranslated region of the DMPK gene. Direct analysis by Southern blot, after restriction enzyme digestion of genomic DNA, is the method of choice for studying the DM mutation. A long polymerase chain reaction (PCR)-formatted protocol, which involved a single genomic in vitro amplification followed by high concentration agarose gel electrophoresis and oligo-specific hybridization, was used to amplify normal alleles and DM alleles in all examined ranges of expansion (up to 3,700 CTGs) starting from a small amount of genomic DNA (> or = 15 pg). This method is quick, sensitive, and reproducible and reduces the cost of diagnostic laboratory processing.

Genomic instability associated with myotonic dystrophy does not involve p53 expression and activity

We tested the hypothesis that the instability of the trinucleotide CTG at the myotonic dystrophy (DM) locus could be an intrinsic DNA damage recognisable by the p53 cell-cycle checkpoint system. p53 mRNA and protein levels were assayed in muscle biopsies and fibroblast cell lines of DM patients and unaffected controls. No differences in mRNA and protein levels were found between patients and controls, regardless of their expansion size. However, in the cells treated with adryamicin, p53 protein levels were comparable in DM and control cells. We conclude that the CTG trinucleotide expansion within the myotonin gene does not activate the p53 surveillance system, at least in adult tissues. The escape of trinucleotide expansion from the p53-mediated DNA repair system could explain some of the biological characteristics of genome instability.

First-trimester prenatal diagnosis of Ellis-van Creveld syndrome using linked microsatellite markers

We report a personal experience of first-trimester prenatal diagnosis of Ellis-van Creveld (EvC) syndrome based on typing of microsatellite markers flanking the EvC locus. An heterozygous fetus was diagnosed with a diagnostic accuracy of 96 per cent. The DNA prediction was confirmed by ultrasound at 22 weeks of gestation and by clinical evaluation at birth.

Positive correlation of CTG expansion and pharyngoesophageal alterations in myotonic dystrophy patients

Alteration of the pharyngoesophageal musculature is a common finding in patients with myotonic dystrophy (MD), regardless of the presence of dysphagia. The aim of the present study was to determine whether a specific pattern of swallowing abnormalities could be identified in MD patients, and the possible correlation with the size of CTG repeats. Fifteen MD patients, 8 of whom were asymptomatic for dysphagia, underwent a videofluoroscopic study of swallowing. Alterations of the pharyngoesophageal phase of swallowing were detected in 12 of 15 patients, 6 without clinical evidence of dysphagia. Incomplete relaxation of the upper esophageal sphincter (UES) and esophageal hypotonia were the most common alterations. We found a significant correlation between the number of radiological alterations and the size of CTG repeats. A typical radiological pattern of swallowing has also been identified. The role of videofluoroscopy in evaluation of MD patients is briefly discussed.

Expression study of survival motor neuron gene in human fetal tissues

In order to investigate the spinal muscular atrophy (SMA) disease processes, the expression of the survival motor neuron gene (SMN) has been analyzed in human fetal tissues using RT-PCR and in situ hybridization. These studies allowed the detection of SMN RNA in all the examined tissues, with no significant variation between different developmental stages. In particular, SMN mRNA was detected in spinal cord (dorsal and ventral portions), skeletal muscle, lung, heart, kidney, liver, and spleen. Moreover, RT-PCR studies demonstrated that the expression pattern of SMN isoforms was similar to that observed in adult tissues. The present data confirm a housekeeping role for the SMN protein and may have implications on the search for early therapeutic strategies.

Expression of receptors for native and chemically modified low-density lipoproteins in brain microvessels

Despite the importance of cholesterol metabolism in the central nervous system, only relatively few studies have dealt with the cerebral uptake and transport of lipids into the brain compartment. These functions are mediated by the endothelium of brain microvessels, which forms the anatomical basis of the blood-brain barrier. By a reverse transcriptase PCR study of messenger RNA expression we could show, in bovine brain microvessels, the presence of transcripts of native low-density lipoprotein receptor and of both type I and II scavenger receptors. Brain microvessels therefore appear to play an active role in the uptake of native and modified low-density lipoproteins.

Prediction of myotonic dystrophy clinical severity based on the number of intragenic [CTG]n trinucleotide repeats

We carried out a genotype-phenotype correlation study, based on clinical findings in 465 patients with myotonic dystrophy (DM), in order to assess [CTG] repeat number as a predictive test of disease severity. Our analysis showed that the DM subtypes defined by strict clinical criteria fall into three different classes with a log-normal distribution. This distribution is useful in predicting the probability of specific DM phenotypes based on triplet [CTG] number. This study demonstrates that measurement of triplet expansions in patients' lymphocyte DNA is highly valuable and accurate for prognostic assessment.