Novel mutations in the toll like receptor genes cause hyporesponsiveness to Mycobacterium avium subsp. paratuberculosis infection

Toll like receptors play a central role in the recognition of pathogen associated molecular patterns (PAMPs). Mutations in TLR1, TLR2 and TLR4 genes may change the PAMP reorganization ability which causes altered responsiveness to the bacterial pathogens. A case control study, performed to assess the association between TLR gene mutations and susceptibility to Mycobacterium avium subsp. paratuberculosis (MAP), revealed novel mutations (TLR1 - Ser150Gly and Val220Met; TLR2 - Phe670Leu) that hindered either PAMP recognition or further downstream TLR pathway activation. A cytokine expression experiments (IL-4, IL-8, IL-10, IL-12 and IFN-γ) in the challenged mutant and wild type moDCs (mocyte derived dendritic cells) confirmed the negative impact of these mutations and altered TLR downstream activation. Further In silico analysis of the TLR1 and TLR4 ectodomains (ECD) revealed the polymorphic nature of the central ECD and irregularities in the central LRR motifs. The most critical positions that may alter the pathogen recognition ability of TLR were: the 9th amino acid position in LRR motif (TLR1, LRR10) and 4th residue downstream to LRR domain (exta LRR region of TLR4). The study describes novel mutations in the TLRs and presents their association with the MAP infection

Folding of Alzheimer's core PHF subunit revealed by monoclonal antibody 423

AbstractAt present, the conformation-dependent monoclonal antibodies (mAb) provide the only information on folding of tau in the core PHF. Monoclonal antibody MN423 recognizes all and only those Alzheimer's disease (AD) core paired helical filaments (PHFs) subunits, which terminate at Glu391. Using recombinant analogs of the core PHF subunit corresponding to tau residues τ297–391, we found that the C-terminal pentapeptide 387DHGAE391 represented only one component of the structure recognized by mAb 423. Therefore, deletion mutants of the core subunit were generated to identify assembled parts of this conformational structure. We localized two spatially close components in the region 306–325 (306VQIVYK311 and 321KCGSL325) contributing to formation of the structure identified by mAb 423. Thus, the spatial proximity of three subunit segments 306VQIVYK311, 321KCGSL325 and 387DHGAE391 represents constraints for intramolecular folding of the core PHF subunit. Since PHF represents a compelling drug target in AD, structural knowledge presented could contribute to structure-based drug design

A walk through tau therapeutic strategies.

Tau neuronal and glial pathologies drive the clinical presentation of Alzheimer's disease and related human tauopathies. There is a growing body of evidence indicating that pathological tau species can travel from cell to cell and spread the pathology through the brain. Throughout the last decade, physiological and pathological tau have become attractive targets for AD therapies. Several therapeutic approaches have been proposed, including the inhibition of protein kinases or protein-3-O-(N-acetyl-beta-D-glucosaminyl)-L-serine/threonine Nacetylglucosaminyl hydrolase, the inhibition of tau aggregation, active and passive immunotherapies, and tau silencing by antisense oligonucleotides. New tau therapeutics, across the board, have demonstrated the ability to prevent or reduce tau lesions and improve either cognitive or motor impairment in a variety of animal models developing neurofibrillary pathology. The most advanced strategy for the treatment of human tauopathies remains immunotherapy, which has already reached the clinical stage of drug development. Tau vaccines or humanised antibodies target a variety of tau species either in the intracellular or extracellular spaces. Some of them recognise the amino-terminus or carboxy-terminus, while others display binding abilities to the proline-rich area or microtubule binding domains. The main therapeutic foci in existing clinical trials are on Alzheimer's disease, progressive supranuclear palsy and non-fluent primary progressive aphasia. Tau therapy offers a new hope for the treatment of many fatal brain disorders. First efficacy data from clinical trials will be available by the end of this decade

MIRRAGGE – Minimum Information Required for Reproducible AGGregation Experiments

Reports on phase separation and amyloid formation for multiple proteins and aggregation-prone peptides are recurrently used to explore the molecular mechanisms associated with several human diseases. The information conveyed by these reports can be used directly in translational investigation, e.g., for the design of better drug screening strategies, or be compiled in databases for benchmarking novel aggregation-predicting algorithms. Given that minute protocol variations determine different outcomes of protein aggregation assays, there is a strong urge for standardized descriptions of the different types of aggregates and the detailed methods used in their production. In an attempt to address this need, we assembled the Minimum Information Required for Reproducible Aggregation Experiments (MIRRAGGE) guidelines, considering first-principles and the established literature on protein self-assembly and aggregation. This consensus information aims to cover the major and subtle determinants of experimental reproducibility while avoiding excessive technical details that are of limited practical interest for non-specialized users. The MIRRAGGE table (template available in Supplementary Information) is useful as a guide for the design of new studies and as a checklist during submission of experimental reports for publication. Full disclosure of relevant information also enables other researchers to reproduce results correctly and facilitates systematic data deposition into curated databases

Novel mutations in TLR genes cause hyporesponsiveness to Mycobacterium avium subsp. paratuberculosis infection

<p>Abstract</p> <p>Background</p> <p>Toll like receptors (TLR) play the central role in the recognition of pathogen associated molecular patterns (PAMPs). Mutations in the TLR1, TLR2 and TLR4 genes may change the ability to recognize PAMPs and cause altered responsiveness to the bacterial pathogens.</p> <p>Results</p> <p>The study presents association between TLR gene mutations and increased susceptibility to <it>Mycobacterium avium </it>subsp. <it>paratuberculosis </it>(MAP) infection. Novel mutations in TLR genes (TLR1- Ser150Gly and Val220Met; TLR2 – Phe670Leu) were statistically correlated with the hindrance in recognition of MAP legends. This correlation was confirmed subsequently by measuring the expression levels of cytokines (IL-4, IL-8, IL-10, IL-12 and IFN-γ) in the mutant and wild type moDCs (mocyte derived dendritic cells) after challenge with MAP cell lysate or LPS. Further <it>in silico </it>analysis of the TLR1 and TLR4 ectodomains (ECD) revealed the polymorphic nature of the central ECD and irregularities in the central LRR (leucine rich repeat) motifs.</p> <p>Conclusion</p> <p>The most critical positions that may alter the pathogen recognition ability of TLR were: the 9^thamino acid position in LRR motif (TLR1–LRR10) and 4^thresidue downstream to LRR domain (exta-LRR region of TLR4). The study describes novel mutations in the TLRs and presents their association with the MAP infection.</p

Crystallization and preliminary X-ray diffraction analysis of two peptides from Alzheimer PHF in complex with the MN423 antibody Fab fragment

The major constituent of the Alzheimer's disease paired helical filaments (PHF) core is the intrinsically disordered protein (IDP) tau. Globular binding partners, e.g. monoclonal antibodies, can stabilize the fold of disordered tau in complexes. A previously published structure of a proteolytically generated tau fragment in a complex with the PHF-specific monoclonal antibody MN423 revealed a turn-like structure of the PHF core C-terminus [Sevcik et al. (2007). FEBS Lett. 581, 5872-5878]. To examine the structures of longer better-defined PHF segments, crystals of the MN423 Fab fragment were grown in the presence of two synthetic peptides derived from the PHF core C-terminus. For each, X-ray diffraction data were collected at 100 K at a synchrotron source and initial phases were obtained by molecular replacement

Time to Kill and Time to Heal: The Multifaceted Role of Lactoferrin and Lactoferricin in Host Defense

Lactoferrin is an iron-binding glycoprotein present in most human exocrine fluids, particularly breast milk. Lactoferrin is also released from neutrophil granules, and its concentration increases rapidly at the site of inflammation. Immune cells of both the innate and the adaptive immune system express receptors for lactoferrin to modulate their functions in response to it. On the basis of these interactions, lactoferrin plays many roles in host defense, ranging from augmenting or calming inflammatory pathways to direct killing of pathogens. Complex biological activities of lactoferrin are determined by its ability to sequester iron and by its highly basic N-terminus, via which lactoferrin binds to a plethora of negatively charged surfaces of microorganisms and viruses, as well as to mammalian cells, both normal and cancerous. Proteolytic cleavage of lactoferrin in the digestive tract generates smaller peptides, such as N-terminally derived lactoferricin. Lactoferricin shares some of the properties of lactoferrin, but also exhibits unique characteristics and functions. In this review, we discuss the structure, functions, and potential therapeutic uses of lactoferrin, lactoferricin, and other lactoferrin-derived bioactive peptides in treating various infections and inflammatory conditions. Furthermore, we summarize clinical trials examining the effect of lactoferrin supplementation in disease treatment, with a special focus on its potential use in treating COVID-19