Abstract
Background
Alzheimer’s disease is characterized by the extracellular accumulation of amyloid beta (Aß), intraneuronal formation of neurofibrillary tangles made of hyperphosphorylated tau and ...activated microglial cells, the innate immune cells of the brain. Activation of microglia by Aß or other DAMPs results in the assembly of the NLRP3 inflammasome consisting of NLRP3, ASC and Caspase‐1. This leads to subsequent production and secretion of inflammatory mediators including IL‐1β and ASC specks. Here, we investigate a contribution of the NLRP3 inflammasome to the development and progression of tau pathology.
Method
Tau22 transgenic mice, that express human 4‐repeat tau mutated at sites G272V and P301S under a Thy1.2‐promotor, were crossed into either NLRP3 inflammasome knockout or ASC knockout mice and analyzed before development of tau pathology (3 month of age) and when robust tau pathology is present (11 month of age). Animals underwent behavioral phenotyping, analysis of pathology as well as assessement of microglial activation. Additionally, Tau22/NLRP3‐knockout and Tau22/ASC‐knockout mice received an injection of Aß‐containing APP/PS1 mouse brain derived lysates to study Aß‐induced spreading of tau pathology. For in vitro studies, primary mouse microglia were treated with different forms of tau and analyzed for NLRP3 inflammasome activation.
Result
NLRP3 inflammasome activation was increased in fronto‐temporal dementia patients as well as in Tau22 mice. Knockout of ASC or NLRP3 in Tau22 mice decreased levels of active tau kinases while increasing activity of phosphatase PP2A in the hippocampus. This strongly protected from accumulation of hyperphosphorylated, misfolded tau in ASC knockout and more robustly in NLRP3 knockout mice while attenuating behavioral deficits. Furthermore, loss of NLRP3 inflammasome function ameliorated Aß‐induced tau pathology. In vitro, treatment of microglia with tau‐containing mouse brain homogenates or recombinant tau monomers and oligomers resulted in IL‐1β release in a NLRP3‐dependet manner, most likely mediated via TLR4. However, the same concentration of recombinant tau fibrils did not evoke this response.
Conclusion
These findings are in line with the hypothesis that innate immune activation represents an important pathogenic factor for tau pathology. In Alzheimer’s disease, early Aß deposition may cause subsequent tau pathology and neuronal demise through NLRP3‐mediated innate immune pathways.
Provider: - Institution: - Data provided by Europeana Collections- Köln, Universität zu Köln, Diss., 2014- All metadata published by Europeana are available free of restriction under the Creative ...Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Summary
Objective Emotional and behavioural alterations have been described in acromegalic patients. However, the nature and psychopathological value of these changes remained unclear.
We examined ...whether acromegalic patients have an increased prevalence of comorbid DSM‐IV (Diagnostic and Statistical Manual of Mental Disorders, 4th Version) mental disorders in comparison to subjects with or without chronic somatic disorders.
Design/patients A cross‐sectional study was conducted at the Max‐Planck Institute of Psychiatry and the Ludwig‐Maximilians‐University Munich. Eighty‐one acromegalic patients were enrolled. Control subjects with (n = 3281) and without chronic somatic (n = 430) disorders were drawn from a representative sample of the German adult general population as part of the Mental Health Supplement of the German Health Interview and Examination Survey. Lifetime and 12‐month prevalences of DSM‐IV mental disorders were assessed with face‐to‐face interviews using the standardized German computer‐assisted version of the Composite International Diagnostic Interview.
Results Acromegalic patients had increased lifetime rates of affective disorders of 34·6% compared to 21·4% in the group with chronic somatic disorders (OR = 2·0, 95% CI 1·2–3·2) and to 11·1% in the group without chronic somatic disorders (OR = 4·4, 95% CI 2·3–8·7). Affective disorders that occurred significantly more often than in the control groups began during the putative period of already present GH excess. Higher rates of DSM‐IV mental disorders were reported in those patients with additional treatment after surgery.
Conclusion Acromegaly is associated with an increased prevalence and a specific pattern of affective disorders. Greater emphasis on diagnosing and treatment of mental disorders in acromegalic patients might improve the disease management.
We conducted a genome-wide association study (GWAS) on multiple sclerosis (MS) susceptibility in German cohorts with 4888 cases and 10,395 controls. In addition to associations within the major ...histocompatibility complex (MHC) region, 15 non-MHC loci reached genome-wide significance. Four of these loci are novel MS susceptibility loci. They map to the genes L3MBTL3, MAZ, ERG, and SHMT1. The lead variant at SHMT1 was replicated in an independent Sardinian cohort. Products of the genes L3MBTL3, MAZ, and ERG play important roles in immune cell regulation. SHMT1 encodes a serine hydroxymethyltransferase catalyzing the transfer of a carbon unit to the folate cycle. This reaction is required for regulation of methylation homeostasis, which is important for establishment and maintenance of epigenetic signatures. Our GWAS approach in a defined population with limited genetic substructure detected associations not found in larger, more heterogeneous cohorts, thus providing new clues regarding MS pathogenesis.
Diagnosis of acromegaly is delayed up to 10 years after disease onset despite obvious external/objective changes such as bone and soft tissue deformities. We hypothesized that a lack of subjective ...perception of the disease state, possibly mediated by psychiatric or cognitive alterations, might contribute to the delayed initiation of a diagnostic workup.
Cross-sectional study.
We investigated perceived body image by standardized questionnaires (FKB-20: Fragebogen zum Körperbild; FBeK: Fragebogen zur Beurteilung des eigenen Körpers) in 81 acromegalic patients and contrasted them to (a) a clinical control group of 60 patients with nonfunctioning pituitary adenomas (NFPA) who lack severe facial and physical alterations and (b) healthy controls. We further evaluated body image in relation to objective acromegalic changes as judged by medical experts and psychiatric pathology, e.g. depression and cognitive impairment.
Patients with acromegaly did not lack subjective perception of the disease state; they showed more negative body image, less vitality, more insecurity/paresthesia and more accentuation of the body compared to normal controls. NFPA patients differed from acromegalic patients only in the 'vital body dynamics' scale of the FKB-20, although they hardly exhibit any physical/bodily changes. Depression correlated with worse body image. No associations were found between body image and objective acromegalic changes as judged by medical experts, cognitive decline or treatment status.
Negative body image in acromegalic patients is unrelated to their objective appearance and similar to those of NFPA patients without major bodily changes. Depression, but not cognitive decline or treatment status, contributes to negative body image.
PDF
