Influence of BDNF Val66Met genetic polymorphism in Major Depressive Disorder and Body Mass Index: Evidence from a meta-analysis of 6481 individuals

BACKGROUND

Major depressive disorder (MDD) and obesity are global health problems that frequently co-occur. Among shared etiological factors, genetic variation at the brain-derived neurotrophic factor (BDNF) gene is interesting since its implication in energy balance regulation, food intake and synaptic function. Thus, the aim of this study was to investigate the influence of the BDNF Val66Met polymorphism in relation to MDD and body mass index (BMI) in two large independent cohorts.

METHODS

The sample consisted of 2646 individuals with MDD and 3835 controls from the PISMA-ep and Radiant studies. Linear regressions were performed to test the association between the polymorphism and BMI and the interaction between the polymorphism and MDD on BMI. A meta-analysis across cohorts was conducted.

RESULTS

No association was found between the polymorphism and BMI. However, we found an association with MDD, showing these individuals higher BMI than controls in both cohorts. No differences were found in BMI depending on Val66Met genotype and no interaction between this polymorphism and MDD in relation to BMI was found. Although a tendency towards an interaction was found in the Radiant sample, the results of the meta-analysis did not support this finding.

LIMITATIONS

The use of self-reported height and weight measures to calculate BMI values.

CONCLUSIONS

We provide evidence for an association between BMI and MDD confirming previous results. Our meta-analysis including two large cohorts showed no interaction between BDNF, BMI and MDD. Future studies will be needed to confirm the role of this polymorphism in the relationship between BMI and MDD.

Meta-analysis and systematic review of ADGRL3 (LPHN3) polymorphisms in ADHD susceptibility

The gene encoding adhesion G protein-coupled receptor L3 (ADGRL3, also referred to as latrophilin 3 or LPHN3) has been associated with ADHD susceptibility in independent ADHD samples. We conducted a systematic review and a comprehensive meta-analysis to summarize the associations between the most studied ADGRL3 polymorphisms (rs6551665, rs1947274, rs1947275, and rs2345039) and both childhood and adulthood ADHD. Eight association studies (seven published and one unpublished) fulfilled criteria for inclusion in our meta-analysis. We also incorporated GWAS data for ADGRL3. In order to avoid overlapping samples, we started with summary statistics from GWAS samples and then added data from gene association studies. The results of our meta-analysis suggest an effect of ADGRL3 variants on ADHD susceptibility in children (n = 8724/14,644 cases/controls and 1893 families): rs6551665 A allele (Z score = -2.701; p = 0.0069); rs1947274 A allele (Z score = -2.033; p = 0.0421); rs1947275 T allele (Z score = 2.339; p = 0.0978); and rs2345039 C allele (Z score = 3.806; p = 0.0026). Heterogeneity was found in analyses for three SNPs (rs6551665, rs1947274, and rs2345039). In adults, results were not significant (n = 6532 cases/15,874 controls): rs6551665 A allele (Z score = 2.005; p = 0.0450); rs1947274 A allele (Z score = 2.179; p = 0.0293); rs1947275 T allele (Z score = -0.822; p = 0.4109); and rs2345039 C allele (Z score = -1.544; p = 0.1226). Heterogeneity was found just for rs6551665. In addition, funnel plots did not suggest publication biases. Consistent with ADGRL3's role in early neurodevelopment, our findings suggest that the gene is predominantly associated with childhood ADHD.

Surgical technique and outcomes for bilateral humeral lengthening for achondroplasia: 26-year experience

BACKGROUND

Elongation in patients with achondroplasia provides better overall skeletal proportionality and significantly improves such individuals' access to their perineal region to self-manage personal hygiene. This paper describes our surgical technique and outcomes for bilateral humeral lengthening in achondroplasia patients over 26 years.

METHODS

Ours was a retrospective study of 55 patients with achondroplasia-related short stature, in whom bilateral humeral lengthening was performed from 1990 to 2016. We describe the surgical technique and analyze mean gain in humeral length, days using an external fixator, mean percentage of lengthening, external fixation index, type of callus, and complications. Pre- and postoperative radiographic measurements were obtained. Patients also were contacted by telephone and asked about their ability to perform peri-anal self-hygiene and about their overall satisfaction.

RESULTS

In total, 110 humeri were lengthened (28 males and 27 females) with medium elongation of 9.5 cm on the right and 9.6 cm on the left, while averaging 220 days in an external fixator. We observed 14 minor complications. There was no significant association between pin position and type of callus, and elongation most often external and in the presence of a straight callus. Before elongation, 77.1% of patients reported difficulties with perineal hygiene and 85.4% could not put their hands in their pockets. Upon completion of lengthening, 100% could perform both tasks and 94.5% were very satisfied.

CONCLUSIONS

Bilateral humeral elongation yields significant improvements in patient autonomy, with a relatively low complication rate and very high patient satisfaction.

Fruit-specific lectins from banana and plantain

One of the predominant proteins in the pulp of ripe bananas (Musa acuminata L.) and plantains (Musa spp.) has been identified as a lectin. The banana and plantain agglutinins (called BanLec and PlanLec, respectively) were purified in reasonable quantities using a novel isolation procedure, which prevented adsorption of the lectins onto insoluble endogenous polysaccharides. Both BanLec and PlanLec are dimeric proteins composed of two identical subunits of 15 kDa. They readily agglutinate rabbit erythrocytes and exhibit specificity towards mannose. Molecular cloning revealed that BanLec has sequence similarity to previously described lectins of the family of jacalin-related lectins, and according to molecular modelling studies has the same overall fold and three-dimensional structure. The identification of BanLec and PlanLec demonstrates the occurrence of jacalin-related lectins in monocot species, suggesting that these lectins are more widespread among higher plants than is actually believed. The banana and plantain lectins are also the first documented examples of jacalin-related lectins, which are abundantly present in the pulp of mature fruits but are apparently absent from other tissues. However, after treatment of intact plants with methyl jasmonate, BanLec is also clearly induced in leaves. The banana lectin is a powerful murine T-cell mitogen. The relevance of the mitogenicity of the banana lectin is discussed in terms of both the physiological role of the lectin and the impact on food safety.

The impact of immunosuppressive drugs on the analysis of T cell activation

The discovery of the immunosuppressive properties of cyclosporin A (CSA) and its successful utilisation in organ transplantation was a milestone in clinics. CSA has revolutionised transplantation both in term of efficiency and quality-of-life of the patient. In addition, the analysis of the mode of action of CSA has been rewarding in the understanding the mechanisms leading to T lymphocytes activation. CSA binds to a family of cytosolic receptors, the cyclophilins, a highly conserved family of proteins. Once this complex is formed, a third protein, the calcineurin, is recruited. The calcineurin, a calcium-dependent phosphatase, loose its activity when complexed. Dephosphorylation of NFAT, a substrate of calcineurin is a mandatory step for its translocation to the nucleus where NFAT acts as a transactivator involved in the regulation of the genes encoding many cytokines. CSA preventing NFAT dephosphorylation blocks cytokine production this in turn allowing for a better engrafting. The resolution of the tertiary structure of CSA alone or complexed with cyclophilin and calcineurin has important implication in the modelling of new drugs devoid of its side effects. Indeed, the high incidence of cancer is one of the main problems linked to CSA utilisation. Recent data suggest that CSA may promote cancer inducing the transcription of the gene encoding transforming growth factor beta. Other molecules sharing with CSA its immunosuppressive activity were later described. Some of them, as FK506, have the some mode of action; others, as rapamycin, mycophenolate mofetil or leflunomide, act at different steps of T cell activation.

Crystal structure of Urtica dioica agglutinin, a superantigen presented by MHC molecules of class I and class II

BACKGROUND

Urtica dioica agglutinin (UDA), a monomeric lectin extracted from stinging nettle rhizomes, is specific for saccharides containing N-acetylglucosamine (GlcNAc). The lectin behaves as a superantigen for murine T cells, inducing the exclusive proliferation of Vbeta8.3(+) lymphocytes. UDA is unique among known T cell superantigens because it can be presented by major histocompatibility complex (MHC) molecules of both class I and II.

RESULTS

The crystal structure of UDA has been determined in the ligand-free state, and in complex with tri-acetylchitotriose and tetra-acetylchitotetraose at 1.66 A, 1.90 A and 1.40 A resolution, respectively. UDA comprises two hevein-like domains, each with a saccharide-binding site. A serine and three aromatic residues at each site form the principal contacts with the ligand. The N-terminal domain binding site can centre on any residue of a chito-oligosaccharide, whereas that of the C-terminal domain is specific for residues at the nonreducing terminus of the ligand. We have shown previously that oligomers of GlcNAc inhibit the superantigenic activity of UDA and that the lectin binds to glycans on the MHC molecule. We show that UDA also binds to glycans on the T cell receptor (TCR).

CONCLUSIONS

The presence of two saccharide-binding sites observed in the structure of UDA suggests that its superantigenic properties arise from the simultaneous fixation of glycans on the TCR and MHC molecules of the T cell and antigen-presenting cell, respectively. The well defined spacing between the two binding sites of UDA is probably a key factor in determining the specificity for Vbeta8.3(+) lymphocytes.

Isolation and characterization of a jacalin-related mannose-binding lectin from salt-stressed rice (Oryza sativa) plants

A novel plant lectin was isolated from salt-stressed rice (Oryza sativa L.) plants and partially characterized. The lectin occurs as a natural mixture of two closely related isoforms consisting of two identical non-covalently linked subunits of 15 kDa. Both isoforms are best inhibited by mannose and exhibit potent mitogenic activity towards T-lymphocytes. Biochemical analyses and sequence comparisons further revealed that the rice lectins belong to the subgroup of mannose-binding jacalin-related lectins. In addition, it could be demonstrated that the lectins described here correspond to the protein products of previously described salt-stress-induced genes. Our results not only identify the rice lectin as a stress protein but also highlight the possible importance of protein-carbohydrate interactions in stress responses in plants.

Major histocompatibility class I molecules present Urtica dioica agglutinin, a superantigen of vegetal origin, to T lymphocytes

The Urtica dioica agglutinin (UDA) shares with the superantigens the property of activating T cell subsets bearing particular Vbeta segments of the TCR. However, UDA is a lectin capable of binding to many glycoproteins on cell membranes. The implication of MHC versus other glycoproteins in UDA presentation was presently studied. Using mutant mice lacking MHC class I (MHC-I), MHC class II (MHC-II) or both MHC antigens, we provided evidence that MHC-I and MHC-II molecules serve as UDA receptors. Presentation by either one of these molecules ensured similar T cell responses and co-stimulatory signals were mandatory for optimal T cell activation and proliferation both in MHC-I and MHC-II contexts. Remarkably, in the absence of MHC molecules, UDA could not be efficiently presented to T cells by other glycosylated proteins. Surface plasmon resonance studies were used to confirm the binding of UDA to MHC-I molecules using a fusion protein consisting of MHC-I domains and beta2-microglobulin. The results indicated that the interaction between UDA and MHC-I molecules implicated lectin-binding site(s) of UDA. Taken together, our data demonstrate that, in addition to MHC-II antigens, MHC-I molecules serve as an alternative ligand for UDA.

A simple staining method for chromatin in electron microscopy compatible with serial sectioning

The study of the disposition of chromatin in the interphasic nucleus requires the combination of serial sectioning and a specific or preferential chromatin staining. The staining of chromatin with phosphotungstic acid (PTA) chromatin was originally employed on sections of glycolmethacrylate-embedded samples. As it is very difficult to obtain ribbons with this resin, we introduced a modification which consisted of staining the tissue after fixation and before dehydration, in order that epoxy resins can be applied. Several procedures were tried and the best results were attained in the following way. Standard fixation of samples no thicker than 1 mm was carried out with 2.5% glutaraldehyde at pH 7.2 for 1 or 2 h at room temperature; tissues were then rinsed three times with 0.2N HCl adjusted to pH 2.1-2.3 with 0.2N NaOH for 15 min. Staining was held with 3% W/V PTA in 1N HCl adjusted to the same pH. Samples were dehydrated in gradual ethyl alcohol concentrations and Epon-embedded. Post-staining on sections with uranyl-acetate and lead-citrate or other methods may be used to demonstrate other cell components and their relations to chromatin.