Hammer, Christian

[["dc.bibliographiccitation.firstpage","1143"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Molecular Psychiatry"],["dc.bibliographiccitation.lastpage","1149"],["dc.bibliographiccitation.volume","19"],["dc.contributor.author","Hammer, Christian"],["dc.contributor.author","Stepniak, Beata"],["dc.contributor.author","Schneider, Anja"],["dc.contributor.author","Papiol, Sergi"],["dc.contributor.author","Tantra, Martesa"],["dc.contributor.author","Begemann, Martin"],["dc.contributor.author","Sirén, Anna-Leena"],["dc.contributor.author","Pardo, Luis A."],["dc.contributor.author","Sperling, Swetlana"],["dc.contributor.author","Mohd Jofrry, Sue"],["dc.contributor.author","Gurvich, Artem"],["dc.contributor.author","Jensen, Niels"],["dc.contributor.author","Ostmeier, Katrin"],["dc.contributor.author","Lühder, F."],["dc.contributor.author","Probst, Christian"],["dc.contributor.author","Martens, Henrik"],["dc.contributor.author","Gillis, M."],["dc.contributor.author","Saher, Gesine"],["dc.contributor.author","Assogna, F."],["dc.contributor.author","Spalletta, Gianfranco"],["dc.contributor.author","Stöcker, W."],["dc.contributor.author","Schulz, Thomas F."],["dc.contributor.author","Nave, Klaus-Armin"],["dc.contributor.author","Ehrenreich, Hannelore"],["dc.date.accessioned","2017-09-07T11:46:37Z"],["dc.date.available","2017-09-07T11:46:37Z"],["dc.date.issued","2014"],["dc.description.abstract","In 2007, a multifaceted syndrome, associated with anti-NMDA receptor autoantibodies (NMDAR-AB) of immunoglobulin-G isotype, has been described, which variably consists of psychosis, epilepsy, cognitive decline and extrapyramidal symptoms. Prevalence and significance of NMDAR-AB in complex neuropsychiatric disease versus health, however, have remained unclear. We tested sera of 2817 subjects (1325 healthy, 1081 schizophrenic, 263 Parkinson and 148 affective-disorder subjects) for presence of NMDAR-AB, conducted a genome-wide genetic association study, comparing AB carriers versus non-carriers, and assessed their influenza AB status. For mechanistic insight and documentation of AB functionality, in vivo experiments involving mice with deficient blood-brain barrier (ApoE(-/-)) and in vitro endocytosis assays in primary cortical neurons were performed. In 10.5% of subjects, NMDAR-AB (NR1 subunit) of any immunoglobulin isotype were detected, with no difference in seroprevalence, titer or in vitro functionality between patients and healthy controls. Administration of extracted human serum to mice influenced basal and MK-801-induced activity in the open field only in ApoE(-/-) mice injected with NMDAR-AB-positive serum but not in respective controls. Seropositive schizophrenic patients with a history of neurotrauma or birth complications, indicating an at least temporarily compromised blood-brain barrier, had more neurological abnormalities than seronegative patients with comparable history. A common genetic variant (rs524991, P=6.15E-08) as well as past influenza A (P=0.024) or B (P=0.006) infection were identified as predisposing factors for NMDAR-AB seropositivity. The >10% overall seroprevalence of NMDAR-AB of both healthy individuals and patients is unexpectedly high. Clinical significance, however, apparently depends on association with past or present perturbations of blood-brain barrier function."],["dc.identifier.doi","10.1038/mp.2013.110"],["dc.identifier.gro","3150565"],["dc.identifier.pmid","23999527"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/7339"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.title","Neuropsychiatric disease relevance of circulating anti-NMDA receptor autoantibodies depends on blood-brain barrier integrity"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e254"],["dc.bibliographiccitation.journal","Translational Psychiatry"],["dc.bibliographiccitation.volume","3"],["dc.contributor.author","El-Kordi, Ahmed"],["dc.contributor.author","Kästner, Anne"],["dc.contributor.author","Grube, Sabrina"],["dc.contributor.author","Klugmann, M."],["dc.contributor.author","Begemann, Martin"],["dc.contributor.author","Sperling, Swetlana"],["dc.contributor.author","Hammerschmidt, Kurt"],["dc.contributor.author","Hammer, Christian"],["dc.contributor.author","Stepniak, Beata"],["dc.contributor.author","Patzig, Julia"],["dc.contributor.author","Monasterio-Schrader, P. D."],["dc.contributor.author","Strenzke, N."],["dc.contributor.author","Flügge, G."],["dc.contributor.author","Werner, Hauke B."],["dc.contributor.author","Pawlak, R."],["dc.contributor.author","Nave, Klaus-Armin"],["dc.contributor.author","Ehrenreich, Hannelore"],["dc.date.accessioned","2017-09-07T11:46:37Z"],["dc.date.available","2017-09-07T11:46:37Z"],["dc.date.issued","2013"],["dc.description.abstract","Claustrophobia, the well-known fear of being trapped in narrow/closed spaces, is often considered a conditioned response to traumatic experience. Surprisingly, we found that mutations affecting a single gene, encoding a stress-regulated neuronal protein, can cause claustrophobia. Gpm6a-deficient mice develop normally and lack obvious behavioral abnormalities. However, when mildly stressed by single-housing, these mice develop a striking claustrophobia-like phenotype, which is not inducible in wild-type controls, even by severe stress. The human GPM6A gene is located on chromosome 4q32-q34, a region linked to panic disorder. Sequence analysis of 115 claustrophobic and non-claustrophobic subjects identified nine variants in the noncoding region of the gene that are more frequent in affected individuals (P=0.028). One variant in the 3'untranslated region was linked to claustrophobia in two small pedigrees. This mutant mRNA is functional but cannot be silenced by neuronal miR124 derived itself from a stress-regulated transcript. We suggest that loosing dynamic regulation of neuronal GPM6A expression poses a genetic risk for claustrophobia."],["dc.format.extent","12"],["dc.identifier.doi","10.1038/tp.2013.28"],["dc.identifier.gro","3150562"],["dc.identifier.pmid","23632458"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10616"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/7336"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.rights","CC BY-NC-SA 3.0"],["dc.rights.uri","https://creativecommons.org/licenses/by-nc-sa/3.0"],["dc.subject","chromosome 4; GPM6A; human pedigree; miR124; mouse mutant; panic disorder"],["dc.title","A single gene defect causing claustrophobia"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","82"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Annals of Neurology"],["dc.bibliographiccitation.lastpage","94"],["dc.bibliographiccitation.volume","76"],["dc.contributor.author","Dahm, Liane"],["dc.contributor.author","Ott, Christoph"],["dc.contributor.author","Steiner, Johann"],["dc.contributor.author","Stepniak, Beata"],["dc.contributor.author","Teegen, Bianca"],["dc.contributor.author","Saschenbrecker, Sandra"],["dc.contributor.author","Hammer, Christian"],["dc.contributor.author","Borowski, Kathrin"],["dc.contributor.author","Begemann, Martin"],["dc.contributor.author","Lemke, Sandra"],["dc.contributor.author","Rentzsch, Kristin"],["dc.contributor.author","Probst, Christian"],["dc.contributor.author","Martens, Henrik"],["dc.contributor.author","Wienands, Jürgen"],["dc.contributor.author","Spalletta, Gianfranco"],["dc.contributor.author","Weißenborn, Karin"],["dc.contributor.author","Stöcker, Winfried"],["dc.contributor.author","Ehrenreich, Hannelore"],["dc.date.accessioned","2017-09-07T11:46:34Z"],["dc.date.available","2017-09-07T11:46:34Z"],["dc.date.issued","2014"],["dc.description.abstract","ObjectiveWe previously reported an unexpectedly high seroprevalence (∼10%) of N-methyl-D-aspartate-receptor subunit-NR1 (NMDAR1) autoantibodies (AB) in healthy and neuropsychiatrically ill subjects (N = 2,817). This finding challenges an unambiguous causal relationship of serum AB with brain disease. To test whether similar results would be obtained for other brain antigen-directed AB previously connected with pathological conditions, we systematically screened serum samples of 4,236 individuals.MethodsSerum samples of healthy (n = 1,703) versus neuropsychiatrically ill subjects (schizophrenia, affective disorders, stroke, Parkinson disease, amyotrophic lateral sclerosis, personality disorder; total n = 2,533) were tested. For analysis based on indirect immunofluorescence, we used biochip mosaics of frozen brain sections (rat, monkey) and transfected HEK293 cells expressing respective recombinant target antigens.ResultsSeroprevalence of all screened AB was comparable in healthy and ill individuals. None of them, however, reached the abundance of NMDAR1 AB (again ∼10%; immunoglobulin [Ig] G ∼1%). Appreciable frequency was noted for AB against amphiphysin (2.0%), ARHGAP26 (1.3%), CASPR2 (0.9%), MOG (0.8%), GAD65 (0.5%), Ma2 (0.5%), Yo (0.4%), and Ma1 (0.4%), with titers and Ig class distribution similar among groups. All other AB were found in ≤0.1% of individuals (anti–AMPAR-1/2, AQP4, CV2, Tr/DNER, DPPX-IF1, GABAR-B1/B2, GAD67, GLRA1b, GRM1, GRM5, Hu, LGl1, recoverin, Ri, ZIC4). The predominant Ig class depended on antigen location, with intracellular epitopes predisposing to IgG (chi-square = 218.91, p = 2.8 × 10−48).InterpretationTo conclude, the brain antigen-directed AB tested here are comparably detectable in healthy subjects and the disease groups studied here, thus questioning an upfront pathological role of these serum AB."],["dc.identifier.doi","10.1002/ana.24189"],["dc.identifier.gro","3150539"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/7312"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.title","Seroprevalence of autoantibodies against brain antigens in health and disease"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","662"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","EMBO Molecular Medicine"],["dc.bibliographiccitation.lastpage","684"],["dc.bibliographiccitation.volume","6"],["dc.contributor.author","Tantra, Martesa"],["dc.contributor.author","Hammer, Christian"],["dc.contributor.author","Kästner, Anne"],["dc.contributor.author","Dahm, Liane"],["dc.contributor.author","Begemann, Martin"],["dc.contributor.author","Bodda, Chiranjeevi"],["dc.contributor.author","Hammerschmidt, Kurt"],["dc.contributor.author","Giegling, Ina"],["dc.contributor.author","Stepniak, Beata"],["dc.contributor.author","Castillo Venzor, Aracely"],["dc.contributor.author","Konte, Bettina"],["dc.contributor.author","Erbaba, Begun"],["dc.contributor.author","Hartmann, Annette M."],["dc.contributor.author","Tarami, Asieh"],["dc.contributor.author","Schulz-Schaeffer, Walter J."],["dc.contributor.author","Rujescu, Dan"],["dc.contributor.author","Mannan, Ashraf U."],["dc.contributor.author","Ehrenreich, Hannelore"],["dc.date.accessioned","2017-09-07T11:46:35Z"],["dc.date.available","2017-09-07T11:46:35Z"],["dc.date.issued","2014"],["dc.description.abstract","The X-chromosomal MECP2/Mecp2 gene encodes methyl-CpG-binding protein 2, a transcriptional activator and repressor regulating many other genes. We discovered in male FVB/N mice that mild (~50%) transgenic overexpression of Mecp2 enhances aggression. Surprisingly, when the same transgene was expressed in C57BL/6N mice, transgenics showed reduced aggression and social interaction. This suggests that Mecp2 modulates aggressive social behavior. To test this hypothesis in humans, we performed a phenotype-based genetic association study (PGAS) in >1000 schizophrenic individuals. We found MECP2 SNPs rs2239464 (G/A) and rs2734647 (C/T; 3'UTR) associated with aggression, with the G and C carriers, respectively, being more aggressive. This finding was replicated in an independent schizophrenia cohort. Allele-specific MECP2 mRNA expression differs in peripheral blood mononuclear cells by ~50% (rs2734647: C > T). Notably, the brain-expressed, species-conserved miR-511 binds to MECP2 3'UTR only in T carriers, thereby suppressing gene expression. To conclude, subtle MECP2/Mecp2 expression alterations impact aggression. While the mouse data provides evidence of an interaction between genetic background and mild Mecp2 overexpression, the human data convey means by which genetic variation affects MECP2 expression and behavior."],["dc.identifier.doi","10.1002/emmm.201303744"],["dc.identifier.gro","3150551"],["dc.identifier.pmid","24648499"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/11691"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/7325"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Mild expression differences of MECP2 influencing aggressive social behavior"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]