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.

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.

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.

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.

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.

Carotid endarterectomy without angiography: a prospective randomised pilot study

OBJECTIVES

to determine whether duplex ultrasonography alone is an adequate examination prior to carotid endarterectomy.

DESIGN

prospective, randomised, single centre study.

MATERIAL AND METHODS

all patients with carotid bifurcation stenosis greater than 70% - based on duplex scanning - were randomised to arteriography followed by carotid surgery (Group A n=96) or carotid surgery alone (Group B n=90). Study endpoints were neurological complications or death occurring between the day of randomisation and until 30 days after surgery.

RESULTS

major neurological complications of death in 1 (1%) vs 3 (3.3%) patients in group A and B, respectively (n.s.). Minor neurological complications (only TIA) were observed in 0 and 3 (3.3%) patients, respectively.

CONCLUSIONS

complication rates were low in both groups and within the generally accepted rate after carotid surgery in asymptomatic and symptomatic patients.

Genetic aspects of the worldwide colonization process of Ceratitis capitata

Multilocus enzyme electrophoresis data from 26 polymorphic loci (124 alleles) were used to analyze the genetic aspects of the worldwide colonization of Ceratitis capitata (medfly). Eighty-two samples of 17 populations were collected from six regions throughout the species range: Africa, extra-Mediterranean islands (Madeira and Gran Canaria), Mediterranean region, Latin America (Guatemala), Pacific (Hawaii), and Australia. The variability parameters (H, P, A) reveal that the geographical dispersal of medfly from its ancestral source area (East Africa) is associated with a great reduction in variability. The pattern of decreasing variability occurs at two regional levels: in the African-Mediterranean region where the differentiation is gradual, and in the Latin American-Pacific region where some ancestral variability is still present as a consequence of recent colonization. The UPGMA phylogenetic tree, derived from Nei's genetic distances, shows the presence of intraspecific differentiative processes affecting mainly the two island populations, Réunion and Hawaii. The population genetic changes observed in the species range are consistent with both the chronology and the historical circuitous course of the medfly colonization process.