Anti-tau intrabodies: From anti-tau immunoglobulins to the development of functional scFv intrabodies.

Over the last decade, there has been a growing interest in intrabodies and their therapeutic potential. Intrabodies are antibody fragments that are expressed inside a cell to target intracellular antigens. In the context of intracellular protein misfolding and aggregation, such as tau pathology in Alzheimer's disease, intrabodies have become an interesting approach as there is the possibility to target early stages of aggregation.

Development and Characterization of Mouse-Specific Anti-Tau Monoclonal Antibodies: Relevance for Analysis of Murine Tau in Cerebrospinal Fluid.

Background: Clearance of tau seeds by immunization with tau antibodies is currently evaluated as therapeutic strategy to block the spreading of tau pathology in Alzheimer's disease and other tauopathies. Preclinical evaluation of passive immunotherapy is performed in different cellular culture systems and in wild-type and human tau transgenic mouse models. Depending on the preclinical model used, tau seeds or induced aggregates can either be of mouse, human or mixed origin.

IP-LC-MSMS Enables Identification of Three Tau -GlcNAcylation Sites as -GlcNAcase Inhibition Pharmacodynamic Readout in Transgenic Mice Overexpressing Human Tau.

-β-linked -acetylglucosaminylation (-GlcNAcylation) modulates tau phosphorylation and aggregation: the pharmacological increase of tau -GlcNAcylation upon treatment with inhibitors of -GlcNAc hydrolase (OGA) constitutes a potential strategy to tackle neurodegenerative diseases. Analysis of tau -GlcNAcylation could potentially be used as a pharmacodynamic biomarker both in preclinical and clinical studies. The goal of the current study was to confirm tau -GlcNAcylation at S400 as a pharmacodynamic readout of OGA inhibition in P301S transgenic mice overexpressing human tau and treated with the OGA inhibitor Thiamet G and to explore if additional -GlcNAcylation sites on tau could be identified.

Development of immunoprecipitation - two-dimensional liquid chromatography - mass spectrometry methodology as biomarker read-out to quantify phosphorylated tau in cerebrospinal fluid from Alzheimer disease patients.

In Alzheimer's disease (AD) brain, one of the histopathological hallmarks is the neurofibrillary tangles consisting of aggregated and hyperphosphorylated tau. Currently many tau binding antibodies are under development to target the extracellular species responsible for the spreading of the disease in the brain. As such, an in-house developed antibody JNJ-63733657 with picomolar affinity towards tau phosphorylated at both T212 and T217 (further named p217+tau) was recently tested in phase I clinical trial NCT03375697.

Development and validation of a high-sensitivity assay for measuring p217+tau in plasma.

Introduction: Diagnosis of Alzheimer's disease (AD) based on amyloid beta (A), pathologic tau (T), and neurodegeneration (N) biomarkers in peripheral fluids promises to accelerate clinical trials and intercept disease earlier.

Methods: Qualification of a Simoa plasma p217+tau assay was performed, followed by clinical utility evaluation in a cohort of 227 subjects with broad A and T spectrum.

Results: The p217+tau plasma assay was accurate, precise, dilution linear, and highly sensitive.

Discovery and Functional Characterization of hPT3, a Humanized Anti-Phospho Tau Selective Monoclonal Antibody.

Background: As a consequence of the discovery of an extracellular component responsible for the progression of tau pathology, tau immunotherapy is being extensively explored in both preclinical and clinical studies as a disease modifying strategy for the treatment of Alzheimer's disease.

Objective: Describe the characteristics of the anti-phospho (T212/T217) tau selective antibody PT3 and its humanized variant hPT3.

Methods: By performing different immunization campaigns, a large collection of antibodies has been generated and prioritized.

Development and Validation of a High Sensitivity Assay for Measuring p217 + tau in Cerebrospinal Fluid.

Background: Early and accurate detection and staging is critical to managing Alzheimer's disease (AD) and supporting clinical trials. Cerebrospinal fluid (CSF) biomarkers for amyloid-β peptides, tau species, and various neurodegenerative and inflammatory analytes are leading the way in this regard, yet there is room for improved sensitivity and specificity. In particular tau is known to be present in many different fragments, conformations, and post-translationally modified forms.

Cerebrospinal fluid p-tau217 performs better than p-tau181 as a biomarker of Alzheimer's disease.

Cerebrospinal fluid (CSF) p-tau181 (tau phosphorylated at threonine 181) is an established biomarker of Alzheimer's disease (AD), reflecting abnormal tau metabolism in the brain. Here we investigate the performance of CSF p-tau217 as a biomarker of AD in comparison to p-tau181. In the Swedish BioFINDER cohort (n = 194), p-tau217 shows stronger correlations with the tau positron emission tomography (PET) tracer [F]flortaucipir, and more accurately identifies individuals with abnormally increased [F]flortaucipir retention.

Neural oscillations during cognitive processes in an App knock-in mouse model of Alzheimer's disease pathology.

Multiple animal models have been created to gain insight into Alzheimer's disease (AD) pathology. Among the most commonly used models are transgenic mice overexpressing human amyloid precursor protein (APP) with mutations linked to familial AD, resulting in the formation of amyloid β plaques, one of the pathological hallmarks observed in AD patients. However, recent evidence suggests that the overexpression of APP by itself can confound some of the reported observations.

CSF1R inhibitor JNJ-40346527 attenuates microglial proliferation and neurodegeneration in P301S mice.

Neuroinflammation and microglial activation are significant processes in Alzheimer's disease pathology. Recent genome-wide association studies have highlighted multiple immune-related genes in association with Alzheimer's disease, and experimental data have demonstrated microglial proliferation as a significant component of the neuropathology. In this study, we tested the efficacy of the selective CSF1R inhibitor JNJ-40346527 (JNJ-527) in the P301S mouse tauopathy model.

Anti-Tau Monoclonal Antibodies Derived from Soluble and Filamentous Tau Show Diverse Functional Properties in vitro and in vivo.

The tau spreading hypothesis provides rationale for passive immunization with an anti-tau monoclonal antibody to block seeding by extracellular tau aggregates as a disease-modifying strategy for the treatment of Alzheimer's disease (AD) and potentially other tauopathies. As the biochemical and biophysical properties of the tau species responsible for the spatio-temporal sequences of seeding events are poorly defined, it is not yet clear which epitope is preferred for obtaining optimal therapeutic efficacy. Our internal tau antibody collection has been generated by immunizations with different tau species: aggregated- and non-aggregated tau and human postmortem AD brain-derived tau fibrils.

Novel Phospho-Tau Monoclonal Antibody Generated Using a Liposomal Vaccine, with Enhanced Recognition of a Conformational Tauopathy Epitope.

The microtubule-associated protein Tau is an intrinsically unfolded, very soluble neuronal protein. Under still unknown circumstances, Tau protein forms soluble oligomers and insoluble aggregates that are closely linked to the cause and progression of various brain pathologies, including Alzheimer's disease. Previously we reported the development of liposome-based vaccines and their efficacy and safety in preclinical mouse models for tauopathy.

Phosphorylation of protein Tau by GSK3β prolongs survival of bigenic Tau.P301L×GSK3β mice by delaying brainstem tauopathy.

Tau.P301L transgenic mice suffer precocious mortality between ages 8 and 11 months, resulting from upper airway defects caused by tauopathy in autonomic brainstem circuits that control breathing (Dutschmann et al., 2010).

Increasing brain protein O-GlcNAc-ylation mitigates breathing defects and mortality of Tau.P301L mice.

The microtubule associated protein tau causes primary and secondary tauopathies by unknown molecular mechanisms. Post-translational O-GlcNAc-ylation of brain proteins was demonstrated here to be beneficial for Tau.P301L mice by pharmacological inhibition of O-GlcNAc-ase.

Efficacy and safety of a liposome-based vaccine against protein Tau, assessed in tau.P301L mice that model tauopathy.

Progressive aggregation of protein Tau into oligomers and fibrils correlates with cognitive decline and synaptic dysfunction, leading to neurodegeneration in vulnerable brain regions in Alzheimer's disease. The unmet need of effective therapy for Alzheimer's disease, combined with problematic pharmacological approaches, led the field to explore immunotherapy, first against amyloid peptides and recently against protein Tau. Here we adapted the liposome-based amyloid vaccine that proved safe and efficacious, and incorporated a synthetic phosphorylated peptide to mimic the important phospho-epitope of protein Tau at residues pS396/pS404.

Protein tau: prime cause of synaptic and neuronal degeneration in Alzheimer's disease.

The microtubule-associated protein Tau (MAPT) is a major component of the pathogenesis of a wide variety of brain-damaging disorders, known as tauopathies. These include Alzheimer's disease (AD), denoted as secondary tauopathy because of the obligatory combination with amyloid pathology. In all tauopathies, protein Tau becomes aberrantly phosphorylated, adopts abnormal conformations, and aggregates into fibrils that eventually accumulate as threads in neuropil and as tangles in soma.

Neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) slows down Alzheimer's disease-like pathology in amyloid precursor protein-transgenic mice.

Pituitary adenylate cyclase-activating polypeptide (PACAP) has neuroprotective and neurotrophic properties and is a potent α-secretase activator. As PACAP peptides and their specific receptor PAC1 are localized in central nervous system areas affected by Alzheimer's disease (AD), this study aims to examine the role of the natural peptide PACAP as a valuable approach in AD therapy. We investigated the effect of PACAP in the brain of an AD transgenic mouse model.