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Benzodiazepines are widely administered drugs to treat anxiety and insomnia. In addition to tolerance development and abuse liability, their chronic use may cause cognitive impairment and increase the risk for dementia. However, the mechanism by which benzodiazepines might contribute to persistent cognitive decline remains unknown. Here we report that diazepam, a widely prescribed benzodiazepine, impairs the structural plasticity of dendritic spines, causing cognitive impairment in mice. Diazepam induces these deficits via the mitochondrial 18 kDa translocator protein (TSPO), rather than classical γ-aminobutyric acid type A receptors, which alters microglial morphology, and phagocytosis of synaptic material. Collectively, our findings demonstrate a mechanism by which TSPO ligands alter synaptic plasticity and, as a consequence, cause cognitive impairment.

Additional file 1. Supplementary Table 1: Description of study cohort. Supplementary Table 2: Primers used for TP53 amplification and Sanger sequencing. Supplementary Table 3: Common TP53 variants in the study cohort. Supplementary Table 4: Comparison of TP53 mutant versus TP53 wild type group. Supplementary Figure 1. Chromatograms showing the TP53 variants found in the corticotroph tumor of patient #1 and #8 (Table 1). A. The variant c.398T>A was present in homozygocity in the tumor and absent in the blood. B. The variant c.1009C>G is detected in all available surgical specimens in this patient. First and 2nd surgeries were Cushing’s disease tumors and 4th and 5th CTP-BADX/NS.

Objective: ��-amyloid PET (A��-PET) is an important tool for quantification of amyloidosis in the brain of suspected Alzheimer's disease (AD) patients and transgenic AD mouse models. Despite the excellent correlation of A��-PET with gold standard immunohistochemical assessments, the relative contributions of fibrillar and non-fibrillar A�� components to the in vivo A��-PET signal remain unclear. Thus, we obtained two murine cerebral amyloidosis models that present with distinct A�� plaque compositions and performed regression analysis between immunohistochemistry and A�� PET to determine the biochemical contributions to A��-PET signal in vivo. Methods: We investigated groups of AppNL-G-F and APPPS1 mice at three, six and 12 months of age by longitudinal 18F-florbetaben A��-PET and with immunohistochemical analysis of the fibrillar and total A�� burdens. We then applied group level inter-modality regression models using age and genotype matched sets of fibrillar/ non-fibrillar A�� data (predictors) and A��-PET results (outcome) for both transgenic models. An independent group of double-hit APPPS1 mice with dysfunctional microglia due to knock-out of triggering receptor expression on myeloid cells 2 (Trem2-/-) served for validation and evaluation of translational impact. Results: Neither fibrillar nor non-fibrillar A�� content alone sufficed to explain the A��-PET findings in either transgenic AD model. However, a regression model compiling fibrillar and non-fibrillar A�� together with the estimate of individual heterogeneity and age at scanning could explain a 93% of variance of the A��-PET signal (P

Background O-(2-[18F]-fluoroethyl)-L-tyrosine (18F-FET) is a highly sensitive PET tracer for glioma imaging, and its uptake is suggested to be driven by an overexpression of the L-type amino-acid transporter 1 (LAT1). However, 30% of low- and 5% of high-grade gliomas do not present enhanced 18F-FET uptake at primary diagnosis (“18F-FET-negative gliomas”) and the pathophysiologic basis for this phenomenon remains unclear. The aim of this study was to determine the expression of LAT1 in a homogeneous group of newly diagnosed 18F-FET-negative gliomas and to compare them to a matched group of 18F-FET-positive gliomas. Forty newly diagnosed IDH-mutant astrocytomas without 1p/19q codeletion were evaluated (n = 20 18F-FET-negative (tumour-to-background ratio (TBR) 18F-FET-positive gliomas (TBR > 1.6)). LAT1 immunohistochemistry (IHC) was performed using SLC7A5/LAT1 antibody. The percentage of LAT1-positive tumour cells (%) and the staining intensity (range 0–2) were multiplied to an overall score (H-score; range 0–200) and correlated to PET findings as well as progression-free survival (PFS). Results IHC staining of LAT1 expression was positive in both, 18F-FET-positive as well as 18F-FET-negative gliomas. No differences were found between the 18F-FET-negative and 18F-FET-positive group with regard to percentage of LAT1-positive tumour cells, staining intensity or H-score. Interestingly, the LAT1 expression showed a significant negative correlation with the PFS (p = 0.031), whereas no significant correlation was found for TBRmax, neither in the overall group nor in the 18F-FET-positive group only (p = 0.651 and p = 0.140). Conclusion Although LAT1 is reported to mediate the uptake of 18F-FET into tumour cells, the levels of LAT1 expression do not correlate with the levels of 18F-FET uptake in IDH-mutant astrocytomas. In particular, the lack of tracer uptake in 18F-FET-negative gliomas cannot be explained by a reduced LAT1 expression. A higher LAT1 expression in IDH-mutant astrocytomas seems to be associated with a short PFS. Further studies regarding mechanisms influencing the uptake of 18F-FET are necessary.

Objectives: To identify the clinical characteristics of the subgroup of benign progressive supranuclear palsy with particularly long disease duration; to define neuropathological determinants underlying variability in disease duration in progressive supranuclear palsy. Methods: Clinical and pathological features were compared among 186 autopsy-confirmed cases with progressive supranuclear palsy with ≥10 years and shorter survival times. Results: The 45 cases (24.2%) had a disease duration of ≥10 years. The absence of ocular motor abnormalities within the first 3 years from disease onset was the only significant independent clinical predictor of longer survival. Histopathologically, the neurodegeneration parameters in each survival group were paralleled anatomically by the distribution of neuronal cytoplasmic inclusions, whereas the tufted astrocytes displayed anatomically an opposite severity pattern. Most interestingly, we found significantly less coiled bodies in those who survive longer, in contrast to patients with less favorable course. Interpretation: A considerable proportion of patients had a more ”benign” disease course with ≥10 years survival. They had a distinct pattern and evolution of core symptoms compared to patients with short survival. The inverted anatomical patterns of astrocytic tau distribution suggest distinct implications of these cell types in trans-cellular propagation. The tempo of disease progression appeared to be determined mostly by oligodendroglial tau, where the high degree of oligodendroglial tau pathology might affect neuronal integrity and function on top of neuronal tau pathology. The relative contribution of glial tau should be further explored in cellular and animal models. ANN NEUROL 2022.

Supplemental material, sj-pdf-1-jcb-10.1177_0271678X211018904 for Binding characteristics of [18F]PI-2620 distinguish the clinically predicted tau isoform in different tauopathies by PET by Mengmeng Song, Leonie Beyer, Lena Kaiser, Henryk Barthel, Thilo van Eimeren, Ken Marek, Alexander Nitschmann, Maximilian Scheifele, Carla Palleis, Gesine Respondek, Maike Kern, Gloria Biechele, Jochen Hammes, Gèrard Bischof, Michael Barbe, Özgür Onur, Frank Jessen, Dorothee Saur, Matthias L Schroeter, Jost-Julian Rumpf, Michael Rullmann, Andreas Schildan, Marianne Patt, Bernd Neumaier, Olivier Barret, Jennifer Madonia, David S Russell, Andrew W Stephens, Andre Mueller, Sigrun Roeber, Jochen Herms, Kai Bötzel, Adrian Danek, Johannes Levin, Joseph Classen, Günter U Höglinger, Peter Bartenstein, Victor Villemagne, Alexander Drzezga, John Seibyl, Osama Sabri, Guido Boening, Sibylle Ziegler and Matthias Brendel in Journal of Cerebral Blood Flow & Metabolism

Additional file 1. Full patients characteristics with detailed LAT1 H-score values.

Additional file 2: Source data.

Additional file 1: Supplementary figures.

Additional file 1. Characteristics of spinal high-grade astrocytomas with piloid features. Micropgraphs of H&E-stained sections of cases #3, #4, #16 and #23 are shown alongside Manhattan plots showing their respective copy-number profiles. Cases #3, #4, and #23 had deletions of the CDKN2A/B genes, highlighted by blue arrows. Scale bar, 100 µm

BACKGROUND In vivo assessment of neuroinflammation by 18-kDa translocator protein positron-emission-tomography (TSPO-PET) ligands receives growing interest in preclinical and clinical research of neurodegenerative disorders. Higher TSPO-PET binding as a surrogate for microglial activation in females has been reported for cognitively normal humans, but such effects have not yet been evaluated in rodent models of neurodegeneration and their controls. Thus, we aimed to investigate the impact of sex on microglial activation in amyloid and tau mouse models and wild-type controls. METHODS TSPO-PET (18F-GE-180) data of C57Bl/6 (wild-type), AppNL-G-F (��-amyloid model), and P301S (tau model) mice was assessed longitudinally between 2 and 12 months of age. The AppNL-G-F group also underwent longitudinal ��-amyloid-PET imaging (A��-PET; 18F-florbetaben). PET results were confirmed and validated by immunohistochemical investigation of microglial (Iba-1, CD68), astrocytic (GFAP), and tau (AT8) markers. Findings in cerebral cortex were compared by sex using linear mixed models for PET data and analysis of variance for immunohistochemistry. RESULTS Wild-type mice showed an increased TSPO-PET signal over time (female +23%, male +4%), with a significant sex �� age interaction (T = - 4.171, p���

Additional file 1: Supplemental figure 1. Overview of representative images of IBA1 and CD68 immunohistochemistry (IHC) stainings from 2.7-6.6 M: The upper row shows representative images of the cortex (CTX), the lower row shows representative images of the brainstem (BRST). Magnification 40x objective/oil; scale Bar: 30 μm; WT = wild-type; TG = P301S; M = age in months.

BACKGROUND: In 2018-19, Borna disease virus 1 (BoDV-1), the causative agent of Borna disease in horses, sheep, and other domestic mammals, was reported in five human patients with severe to fatal encephalitis in Germany. However, information on case frequencies, clinical courses, and detailed epidemiological analyses are still lacking. We report the occurrence of BoDV-1-associated encephalitis in cases submitted to the Institute of Clinical Microbiology and Hygiene, Regensburg University Hospital, Regensburg, Germany, and provide a detailed description of newly identified cases of BoDV-1-induced encephalitis. METHODS: All brain tissues from 56 encephalitis cases from Bavaria, Germany, of putative viral origin (1999-2019), which had been submitted for virological testing upon request of the attending clinician and stored for stepwise diagnostic procedure, were systematically screened for BoDV-1 RNA. Two additional BoDV-1-positive cases were contributed by other diagnostic centres. Positive results were confirmed by deep sequencing, antigen detection, and determination of BoDV-1-reactive antibodies in serum and cerebrospinal fluid. Clinical and epidemiological data from infected patients were collected and analysed. FINDINGS: BoDV-1 RNA and bornavirus-reactive antibodies were detected in eight newly analysed encephalitis cases and the first human BoDV-1 isolate was obtained from an unequivocally confirmed human BoDV-1 infection from the endemic area. Six of the eight BoDV-1-positive patients had no record of immunosuppression before the onset of fatal disease, whereas two were immunocompromised after solid organ transplantation. Typical initial symptoms were headache, fever, and confusion, followed by various neurological signs, deep coma, and severe brainstem involvement. Seven of nine patients with fatal encephalitis of unclear cause were BoDV-1 positive within one diagnostic centre. BoDV-1 sequence information and epidemiological analyses indicated independent spillover transmissions most likely from the local wild animal reservoir. INTERPRETATION: BoDV-1 infection has to be considered as a potentially lethal zoonosis in endemic regions with reported spillover infections in horses and sheep. BoDV-1 infection can result in fatal encephalitis in immunocompromised and apparently healthy people. Consequently, all severe encephalitis cases of unclear cause should be tested for bornaviruses especially in endemic regions.

Frontotemporal lobar degeneration with neuronal inclusions of the TAR DNA-binding protein 43 (FTLD-TDP) represents the most common pathological subtype of FTLD. We established the international FTLD-TDP whole-genome sequencing consortium to thoroughly characterize the known genetic causes of FTLD-TDP and identify novel genetic risk factors. Through the study of 1131 unrelated Caucasian patients, we estimated that C9orf72 repeat expansions and GRN loss-of-function mutations account for 25.5% and 13.9% of FTLD-TDP patients, respectively. Mutations in TBK1 (1.5%) and other known FTLD genes (1.4%) were rare, and the disease in 57.7% of FTLD-TDP patients was unexplained by the known FTLD genes. To unravel the contribution of common genetic factors to the FTLD-TDP etiology in these patients, we conducted a two-stage association study comprising the analysis of whole-genome sequencing data from 517 FTLD-TDP patients and 838 controls, followed by targeted genotyping of the most associated genomic loci in 119 additional FTLD-TDP patients and 1653 controls. We identified three genome-wide significant FTLD-TDP risk loci: one new locus at chromosome 7q36 within the DPP6 gene led by rs118113626 (p value = 4.82e-08, OR = 2.12), and two known loci: UNC13A, led by rs1297319 (p value = 1.27e-08, OR = 1.50) and HLA-DQA2 led by rs17219281 (p value = 3.22e-08, OR = 1.98). While HLA represents a locus previously implicated in clinical FTLD and related neurodegenerative disorders, the association signal in our study is independent from previously reported associations. Through inspection of our whole-genome sequence data for genes with an excess of rare loss-of-function variants in FTLD-TDP patients (n ≥ 3) as compared to controls (n = 0), we further discovered a possible role for genes functioning within the TBK1-related immune pathway (e.g., DHX58, TRIM21, IRF7) in the genetic etiology of FTLD-TDP. Together, our study based on the largest cohort of unrelated FTLD-TDP patients assembled to date provides a comprehensive view of the genetic landscape of FTLD-TDP, nominates novel FTLD-TDP risk loci, and strongly implicates the immune pathway in FTLD-TDP pathogenesis.

Figure S3. iMG differentiation and validation. a Schematic of the in vitro differentiation of iPSC-derived microglia-like cells (iMG). (i): Human iPSCs are grown in feeder free conditions with no spontaneous differentiation. Scale bar: 250 μm. (ii): Embryoid bodies are formed in the presence of 3 factors SCF, BMP4, and VEGF; Scale bar: 750 μm. (iii): Myeloid cells are generated after culturing with IL3 and MCSF growth factors for 3–4 weeks, then stained for classic myeloid/macrophage markers CD68. Scale bar: 50 μm. (iv): Further differentiation to microglia-like cells that positive for microglial markers P2RY12. Scale bar: 20 μm. (v): Addition of the two final factors (CD200 and CX3CL1) matures the iMG. Scale bar: 20 μm. b Heat map showing mRNA expression of a microglial gene signature in iMG, human monocyte-derived macrophages (hMac), human primary microglia (hMG), and iPSC samples. Clear clustering is observed between iMG and hMG. (PDF 159 kb)

Figure S2. Sequence of the aberrantly spliced murine Trem2 mRNA. Trem2 gene sequence. Exon in black; intron in green; // indicates splicing sites. (PDF 93 kb)

Table S1. Allele specific quantitative PCR for Trem2 R47H knock-in mice (PDF 92 kb)

Table S2. Allele specific quantitative PCR for iMG and patient brains (PDF 104 kb)

Figure S1. Off-target analysis of in-house made Trem2 R47H knock-in mice. a Sanger-sequencing chromatograms of the Trem2 on-target site and the six putative off target sites of animal Trem2 R47H ki ID-7. Mixed peaks in the Trem2 locus show the correct R47H substitution (CGC > CAC) and the three silent mutations for genotyping purposes. Mixed peaks in traces of site #2 reveal a Δ10-Indel mutation at the putative cut site, indicating a true off target event. Underlined: Protospacer; arrow head: putative cut site; green letters: PAM site on shown strand; red letters: PAM site on complementary strand; yellow: Δ10-Indel mutation. b Sanger sequencing results of Trem2 R47H positive off-springs of male ID-7, which was crossed with a C57BL/6 N female. The Δ10-Indel allele was inherited to animals ID-7-3 und ID-7-12 that were excluded from any further breedings and experiments. (PDF 201 kb)

Quantitative study of the neurochemical characteristics of the AxDs. (PDF 351 kb)

Schematic representation of Aβ plaques and AxDs development over time. (PDF 200 kb)

Size ratio of dystrophic segments. (PDF 393 kb)

Re-formation of AxDs and sprouting phenomenon (re-growth) in the APP-PS1 mouse. (PDF 341 kb)

Location of auto-fluorescent spots. (PDF 371 kb)

Correlative light and FIB/SEM microscopy. (PDF 317 kb)

Schematic representation of Aβ plaques and AxDs development over time. (PDF 200 kb)

Relationship between Aβ plaques and AxDs formation and development. Quantitative analysis of different types of Aβ plaques. (PDF 463 kb)

Size ratio of dystrophic segments. (PDF 393 kb)

Behavior of auto-fluorescent spots after the elimination of an AxD. (PDF 204 kb)

Relationship between Aβ plaques and AxDs formation and development. Quantitative analysis of different types of Aβ plaques. (PDF 463 kb)

Quantitative study of the neurochemical characteristics of the AxDs. (PDF 351 kb)

Re-formation of AxDs and sprouting phenomenon (re-growth) in the APP-PS1 mouse. (PDF 341 kb)

Table showing the number of imaging positions that was successfully imaged weekly during near 6 months. (PDF 260 kb)

Behavior of auto-fluorescent spots after the elimination of an AxD. (PDF 204 kb)

Results of normal distribution testing and longitudinal measures of body weight. (DOCX 16 kb)

Results of normal distribution testing and longitudinal measures of body weight. (DOCX 16 kb)