Dissecting the structure, thermodynamic stability, and aggregation properties of the A25T transthyretin (A25T-TTR) variant involved in leptomeningeal amyloidosis: identifying protein partners that co-aggregate during A25T-TTR fibrillogenesis in cerebrospinal fluid

Deposition of amorphous aggregates and fibrils of transthyretin (TTR) in leptomeninges and subarachnoid vessels is a characteristic of leptomeningeal amyloidosis (LA), a currently untreatable cerebral angiopathy. Herein, we report the X-ray structure of the A25T homotetramer of TTR, a natural mutant described in a patient with LA. The structure of A25T-TTR is indistinguishable from that of wild-type TTR (wt-TTR), indicating that the difference in amyloidogenicity between A25T-TTR and wt-TTR cannot be ascribed to gross structural differences. Using pressure-induced dissociation of the tetramer, we show that A25T-TTR is 3 kcal/mol less stable than L55P-TTR, the most aggressive mutant of TTR described to date. After incubation for 15 days at 37 °C (pH 7.3), A25T-TTR forms mature amyloid fibrils. To mimic the environment in which TTR aggregates, we investigated aggregation in cerebrospinal fluid (CSF). Unlike L55P-TTR, A25T-TTR rapidly forms amyloid aggregates in CSF that incorporated several protein partners. Utilizing a proteomics methodology, we identified 19 proteins that copurified with A25T-TTR amyloid fibrils. We confirmed the presence of proteins previously identified to be associated with TTR aggregates in biopsies of TTR amyloidosis patients, such as clusterin, apolipoprotein E, and complement proteins. Moreover, we identified novel proteins, such as blood coagulation proteins. Overall, our results revealed the in vitro characterization of TTR aggregation in a biologically relevant environment, opening new avenues of investigation into the molecular mechanisms of LA.CNPqFAPERJCAPE

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Dissecting the Structure, Thermodynamic Stability, and Aggregation Properties of the A25T Transthyretin (A25T-TTR) Variant Involved in Leptomeningeal Amyloidosis: Identifying Protein Partners That Co-Aggregate during A25T-TTR Fibrillogenesis in Cerebrospinal Fluid

Deposition of amorphous aggregates and fibrils of transthyretin (TTR) in leptomeninges and subarachnoid vessels is a characteristic of leptomeningeal amyloidosis (LA), a currently untreatable cerebral angiopathy. Herein, we report the X-ray structure of the A25T homotetramer of TTR, a natural mutant described in a patient with LA. The structure of A25T-TTR is indistinguishable from that of wild-type TTR (wt-TTR), indicating that the difference in amyloidogenicity between A25T-TTR and wt-TTR cannot be ascribed to gross structural differences. Using pressure-induced dissociation of the tetramer, we show that A25T-TTR is 3 kcal/mol less stable than L55P-TTR, the most aggressive mutant of TTR described to date. After incubation for 15 days at 37 °C (pH 7.3), A25T-TTR forms mature amyloid fibrils. To mimic the environment in which TTR aggregates, we investigated aggregation in cerebrospinal fluid (CSF). Unlike L55P-TTR, A25T-TTR rapidly forms amyloid aggregates in CSF that incorporated several protein partners. Utilizing a proteomics methodology, we identified 19 proteins that copurified with A25T-TTR amyloid fibrils. We confirmed the presence of proteins previously identified to be associated with TTR aggregates in biopsies of TTR amyloidosis patients, such as clusterin, apolipoprotein E, and complement proteins. Moreover, we identified novel proteins, such as blood coagulation proteins. Overall, our results revealed the in vitro characterization of TTR aggregation in a biologically relevant environment, opening new avenues of investigation into the molecular mechanisms of LA

Presenilin 1 phosphorylation regulates amyloid-β degradation by microglia

Amyloid-β peptide (Aβ) accumulation in the brain is a hallmark of Alzheimer’s Disease. An important mechanism of Aβ clearance in the brain is uptake and degradation by microglia. Presenilin 1 (PS1) is the catalytic subunit of γ-secretase, an enzyme complex responsible for the maturation of multiple substrates, such as Aβ. Although PS1 has been extensively studied in neurons, the role of PS1 in microglia is incompletely understood. Here we report that microglia containing phospho-deficient mutant PS1 display a slower kinetic response to micro injury in the brain in vivo and the inability to degrade Aβ oligomers due to a phagolysosome dysfunction. An Alzheimer’s mouse model containing phospho-deficient PS1 show severe Aβ accumulation in microglia as well as the postsynaptic protein PSD95. Our results demonstrate a novel mechanism by which PS1 modulates microglial function and contributes to Alzheimer’s -associated phenotypes

Neutrophil extracellular trap-enriched supernatants carry microRNAs able to modulate TNF-α production by macrophages

Submitted by Fábio Marques ([email protected]) on 2020-03-11T19:02:14Z No. of bitstreams: 1 Neutrophil_Marcelo_Ribeiro-Alves_INI_Lapclin-AIDS_2020.pdf: 5714491 bytes, checksum: 100fa09485db1c68f6bf137e79c8b78e (MD5)Approved for entry into archive by Regina Costa ([email protected]) on 2020-03-12T14:44:54Z (GMT) No. of bitstreams: 1 Neutrophil_Marcelo_Ribeiro-Alves_INI_Lapclin-AIDS_2020.pdf: 5714491 bytes, checksum: 100fa09485db1c68f6bf137e79c8b78e (MD5)Made available in DSpace on 2020-03-12T14:44:54Z (GMT). No. of bitstreams: 1 Neutrophil_Marcelo_Ribeiro-Alves_INI_Lapclin-AIDS_2020.pdf: 5714491 bytes, checksum: 100fa09485db1c68f6bf137e79c8b78e (MD5) Previous issue date: 2020Laboratory of Immunobiology of Leishmaniasis, Department of Immunology, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Timo. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Instituto Nacional de Ciência e Tecnologia em Neuroimunomodulação. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Laboratório de Pesquisa Clínica em DST/AIDS. Rio de Janeiro, RJ, Brasil.Instituto de Bioquimica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Timo. Rio de Janeiro, RJ, Brasil.Laboratory of Immunobiology of Leishmaniasis, Department of Immunology, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.Laboratory of Immunobiology of Leishmaniasis, Department of Immunology, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Timo. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Instituto Nacional de Ciência e Tecnologia em Neuroimunomodulação. Rio de Janeiro, RJ, Brasil.Instituto de Bioquimica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Timo. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Instituto Nacional de Ciência e Tecnologia em Neuroimunomodulação. Rio de Janeiro, RJ, Brasil.Laboratory of Immunobiology of Leishmaniasis, Department of Immunology, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.Neutrophil extracellular traps (NETs) emerge from the cell as a DNA scaffold associated with cytoplasmic and granular proteins, able to immobilize and kill pathogens. This association occurs following nuclear and granular membrane disintegration, allowing contact with the decondensed chromatin. Thus, it is reasonable to speculate that the DNA can also mix with miRNAs and carry them in NETs. Here, we report for the first time the presence of the miRNA carriers associated with NETs and miRNAs present in NET-enriched supernatants (NET-miRs), thus adding a novel class of molecules and new proteins that can be released and transported in the NET platform. We observed that the majority of NET-miRs were common to all four stimuli used (PMA, interleukin-8, amyloid fibrils and Leishmania), and that miRNA-142-3p carried by NETs down-modulates protein kinase Cα and regulates TNF-α production in macrophages upon NET interaction with these cells. Our findings unveil a novel role for NETs in the cell communication processes, allowing the conveyance of miRNA from neutrophils to neighboring cells

Cross talk between brain innate immunity and serotonin signaling underlies depressive-like behavior induced by Alzheimer's amyloid-β oligomers in mice

Considerable clinical and epidemiological evidence links Alzheimer's disease (AD) and depression. However, the molecular mechanisms underlying this connection are largely unknown. We reported recently that soluble A beta oligomers (A beta Os), toxins that accumulate in AD brains and are thought to instigate synapse damage and memory loss, induce depressive-like behavior in mice. Here, we report that the mechanism underlying this action involves A beta O-induced microglial activation, aberrant TNF-alpha signaling, and decreased brain serotonin levels. Inactivation or ablation of microglia blocked the increase in brain TNF-alpha and abolished depressive-like behavior induced by A beta Os. Significantly, we identified serotonin as a negative regulator of microglial activation. Finally, A beta Os failed to induce depressive-like behavior in Toll-like receptor 4-deficient mice and in mice harboring a nonfunctional TLR4 variant in myeloid cells. Results establish that A beta Os trigger depressive-like behavior via a double impact on brain serotonin levels and microglial activation, unveiling a cross talk between brain innate immunity and serotonergic signaling as a key player in mood alterations in AD36481210612116CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJsem informaçã

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

Stoma-free survival after anastomotic leak following rectal cancer resection: worldwide cohort of 2470 patients

Background: The optimal treatment of anastomotic leak after rectal cancer resection is unclear. This worldwide cohort study aimed to provide an overview of four treatment strategies applied. Methods: Patients from 216 centres and 45 countries with anastomotic leak after rectal cancer resection between 2014 and 2018 were included. Treatment was categorized as salvage surgery, faecal diversion with passive or active (vacuum) drainage, and no primary/secondary faecal diversion. The primary outcome was 1-year stoma-free survival. In addition, passive and active drainage were compared using propensity score matching (2: 1). Results: Of 2470 evaluable patients, 388 (16.0 per cent) underwent salvage surgery, 1524 (62.0 per cent) passive drainage, 278 (11.0 per cent) active drainage, and 280 (11.0 per cent) had no faecal diversion. One-year stoma-free survival rates were 13.7, 48.3, 48.2, and 65.4 per cent respectively. Propensity score matching resulted in 556 patients with passive and 278 with active drainage. There was no statistically significant difference between these groups in 1-year stoma-free survival (OR 0.95, 95 per cent c.i. 0.66 to 1.33), with a risk difference of -1.1 (95 per cent c.i. -9.0 to 7.0) per cent. After active drainage, more patients required secondary salvage surgery (OR 2.32, 1.49 to 3.59), prolonged hospital admission (an additional 6 (95 per cent c.i. 2 to 10) days), and ICU admission (OR 1.41, 1.02 to 1.94). Mean duration of leak healing did not differ significantly (an additional 12 (-28 to 52) days). Conclusion: Primary salvage surgery or omission of faecal diversion likely correspond to the most severe and least severe leaks respectively. In patients with diverted leaks, stoma-free survival did not differ statistically between passive and active drainage, although the increased risk of secondary salvage surgery and ICU admission suggests residual confounding