Antisense Reduction of the Protein Tau Attenuates Neuronal Hyperexcitability and Permits Clearance of Intraneuronal Tau Accumulations in vivo

The protein tau is a major contributor in some of the most prevalent neurodegenerative diseases, including the most common form of dementia, Alzheimer\u27s Disease (AD). As a member of the microtubule-associated protein family, tau in enriched in the axons of mature and growing neurons, though under certain conditions, can become hyperphosphorylated and accumulate into toxic oligomeric species and aggregates. In the studies outlined here, we sought to directly target the protein tau using Antisense Oligonucleotides (ASOs) to reduce total expression of tau in vivo and assess if such a reduction could be therapeutically beneficial. To first test the feasibility of reducing tau in the adult animal, we identified ASOs that reduce endogenous mouse tau in the brain and found no effect on baseline motor or cognitive behavior. We then tested the efficacy of reducing murine tau in the context of hyperexcitability since aberrant neuronal excitability has been linked to AD pathogenesis, both in humans and in amyloid-beta depositing mouse models. We found that mice with reduced tau had significantly less severe seizures than control mice, demonstrating that endogenous tau is indeed integral for regulating neuronal hyperexcitability. While the inducible models are sufficient to assess the roles of endogenous tau, non-transgenic mice do not develop tau aggregates. One of the main pathological AD hallmarks is the presence of tau inclusions, so to better test the effect of tau reduction on pathological tau species, we reduced human tau in a transgenic tauopathy mouse model that develops extensive tau pathology. Following treatment with a human tau ASO, not only did reducing human tau prevent additional tau aggregates from forming, it also allowed for a striking reversal of tau accumulations and hippocampal neuronal loss in aged tauopathy mice. Taken together, the safety of reducing endogenous tau in adult animals, the protective effect against neuronal hyperexcitability, and the ability to clear pre-existing tau aggregates, a tau lowering therapy using ASOs may be a viable and strong therapeutic approach for those human patients with a detrimental hyperexcitability profile, tau inclusions, or even both

Validated UPLC-MS/MS methods to quantitate free and conjugated Alternaria toxins in commercially available tomato products and fruit and vegetable juices in Belgium

Ultraperformance liquid chromatography tandem mass spectrometry and Quick, Easy, Cheap, Effective, Rugged, and Safe based analytical methodologies to quantitate both free (alternariol (1), alternariol monomethyl ether (2), tenuazonic acid (3), tentoxin (4), altenuene (5), altertoxin-I (6)) and conjugated (sulfates and glucosides of 1 and 2) Alternaria toxins in fruit and vegetable juices and tomato products were developed and validated. Acceptable limits of quantitation (0.7-5.7 mu g/kg), repeatability (RSDr < 15.7%), reproducibility (RSDR < 17.9%), and apparent recovery (87.0-110.6%) were obtained for all analytes in all matrices investigated. 129 commercial foodstuffs were analyzed, and 3 was detected in 100% of tomato product samples (<LOQ to 333 mu g/kg), while 1, 2, 4, and 5 were also frequently detected (21-86%, <LOQ to 62 mu g/kg). Moreover, low levels (<LOQ to 9.9 mu g/kg) of modified Alternaria toxins (sulfates of 1 and 2) were repeatedly detected. A deterministic dietary exposure assessment revealed the possible risk for human health related to the presence of 1 and 2 in tomato based foodstuffs, whereas 3 is unlikely to be of human health concern

A20 protects cells from TNF-induced apoptosis through linear ubiquitin-dependent and -independent mechanisms

The cytokine TNF promotes inflammation either directly by activating the MAPK and NF-kappa B signaling pathways, or indirectly by triggering cell death. A20 is a potent anti-inflammatory molecule, and mutations in the gene encoding A20 are associated with a wide panel of inflammatory pathologies, both in human and in the mouse. Binding of TNF to TNFR1 triggers the NF-kappa B-dependent expression of A20 as part of a negative feedback mechanism preventing sustained NF-kappa B activation. Apart from acting as an NF-kappa B inhibitor, A20 is also well-known for its ability to counteract the cytotoxic potential of TNF. However, the mechanism by which A20 mediates this function and the exact cell death modality that it represses have remained incompletely understood. In the present study, we provide in vitro and in vivo evidences that deletion of A20 induces RIPK1 kinase-dependent and -independent apoptosis upon single TNF stimulation. We show that constitutively expressed A20 is recruited to TNFR1 signaling complex (Complex I) via its seventh zinc finger (ZF7) domain, in a cIAP1/2-dependent manner, within minutes after TNF sensing. We demonstrate that Complex I-recruited A20 protects cells from apoptosis by stabilizing the linear (M1) ubiquitin network associated to Complex I, a process independent of its E3 ubiquitin ligase and deubiquitylase (DUB) activities and which is counteracted by the DUB CYLD, both in vitro and in vivo. In absence of linear ubiquitylation, A20 is still recruited to Complex I via its ZF4 and ZF7 domains, but this time protects the cells from death by deploying its DUB activity. Together, our results therefore demonstrate two distinct molecular mechanisms by which constitutively expressed A20 protect cells from TNF-induced apoptosis

The genotype of barley cultivars influences multiple aspects of their associated microbiota via differential root exudate secretion

Plant-associated microbes play vital roles in promoting plant growth and health, with plants secreting root exudates into the rhizosphere to attract beneficial microbes. Exudate composition defines the nature of microbial recruitment, with different plant species attracting distinct microbiota to enable optimal adaptation to the soil environment. To more closely examine the relationship between plant genotype and microbial recruitment, we analysed the rhizosphere microbiomes of landrace (Chevallier) and modern (NFC Tipple) barley (Hordeum vulgare) cultivars. Distinct differences were observed between the plant-associated microbiomes of the 2 cultivars, with the plant-growth promoting rhizobacterial genus Pseudomonas substantially more abundant in the Tipple rhizosphere. Striking differences were also observed between the phenotypes of recruited Pseudomonas populations, alongside distinct genotypic clustering by cultivar. Cultivar-driven Pseudomonas selection was driven by root exudate composition, with the greater abundance of hexose sugars secreted from Tipple roots attracting microbes better adapted to growth on these metabolites and vice versa. Cultivar-driven selection also operates at the molecular level, with both gene expression and the abundance of ecologically relevant loci differing between Tipple and Chevallier Pseudomonas isolates. Finally, cultivar-driven selection is important for plant health, with both cultivars showing a distinct preference for microbes selected by their genetic siblings in rhizosphere transplantation assays

In vivo rate-determining steps of tau seed accumulation in Alzheimer's disease.

[Figure: see text].We acknowledge funding from Sidney Sussex College Cambridge (GM) and the European Research Council Grant Number 669237 (to D.K.) and the Royal Society (to D.K.). The Cambridge Brain Bank is supported by the NIHR Cambridge Biomedical Research Centre

Distinct tau prion strains propagate in cells and mice and define different tauopathies

Prion-like propagation of tau aggregation might underlie the stereotyped progression of neurodegenerative tauopathies. True prions stably maintain unique conformations (“strains”) in vivo that link structure to patterns of pathology. We now find that tau meets this criterion. Stably expressed tau repeat domain indefinitely propagates distinct amyloid conformations in a clonal fashion in culture. Reintroduction of tau from these lines into naive cells reestablishes identical clones. We produced two strains in vitro that induce distinct pathologies in vivo as determined by successive inoculations into three generations of transgenic mice. Immunopurified tau from these mice recreates the original strains in culture. We used the cell system to isolate tau strains from 29 patients with 5 different tauopathies, finding that different diseases are associated with different sets of strains. Tau thus demonstrates essential characteristics of a prion. This might explain the phenotypic diversity of tauopathies and could enable more effective diagnosis and therapy

Project #91: Optimizing Vascular Access to Reduce CLABSI

Henry Ford Macomb Hospital experienced an increase in Central Line Associated Bloodstream Infections (CLABSI) in 2021. A significant portion were occurring in the MICU and were associated with Candida sp. Bloodstream infections negatively impact patient outcomes, provider workload, and are costly, with a median cost of $48,108 based on a meta-analysis conducted by AHRQ in 2017. By end of 2022, HFM aimed to reduce CLABSI incidence by 50%.https://scholarlycommons.henryford.com/qualityexpo2023/1004/thumbnail.jp

Synaptic Tau Seeding Precedes Tau Pathology in Human Alzheimer's Disease Brain

Alzheimer's disease (AD) is defined by the presence of intraneuronal neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau aggregates as well as extracellular amyloid-beta plaques. The presence and spread of tau pathology through the brain is classified by Braak stages and thought to correlate with the progression of AD. Several in vitro and in vivo studies have examined the ability of tau pathology to move from one neuron to the next, suggesting a “prion-like” spread of tau aggregates may be an underlying cause of Braak tau staging in AD. Using the HEK293 TauRD-P301S-CFP/YFP expressing biosensor cells as a highly sensitive and specific tool to identify the presence of seed competent aggregated tau in brain lysate—i.e., tau aggregates that are capable of recruiting and misfolding monomeric tau—, we detected substantial tau seeding levels in the entorhinal cortex from human cases with only very rare NFTs, suggesting that soluble tau aggregates can exist prior to the development of overt tau pathology. We next looked at tau seeding levels in human brains of varying Braak stages along six regions of the Braak Tau Pathway. Tau seeding levels were detected not only in the brain regions impacted by pathology, but also in the subsequent non-pathology containing region along the Braak pathway. These data imply that pathogenic tau aggregates precede overt tau pathology in a manner that is consistent with transneuronal spread of tau aggregates. We then detected tau seeding in frontal white matter tracts and the optic nerve, two brain regions comprised of axons that contain little to no neuronal cell bodies, implying that tau aggregates can indeed traverse along axons. Finally, we isolated cytosolic and synaptosome fractions along the Braak Tau Pathway from brains of varying Braak stages. Phosphorylated and seed competent tau was significantly enriched in the synaptic fraction of brain regions that did not have extensive cellular tau pathology, further suggesting that aggregated tau seeds move through the human brain along synaptically connected neurons. Together, these data provide further evidence that the spread of tau aggregates through the human brain along synaptically connected networks results in the pathogenesis of human Alzheimer's disease

Neuronal uptake and propagation of a rare phosphorylated high-molecular-weight tau derived from Alzheimer's disease brain

Tau pathology is known to spread in a hierarchical pattern in Alzheimer's disease (AD) brain during disease progression, likely by trans-synaptic tau transfer between neurons. However, the tau species involved in inter-neuron propagation remains unclear. To identify tau species responsible for propagation, we examined uptake and propagation properties of different tau species derived from postmortem cortical extracts and brain interstitial fluid of tau-transgenic mice, as well as human AD cortices. Here we show that PBS-soluble phosphorylated high-molecular-weight (HMW) tau, though very low in abundance, is taken up, axonally transported, and passed on to synaptically connected neurons. Our findings suggest that a rare species of soluble phosphorylated HMW tau is the endogenous form of tau involved in propagation and could be a target for therapeutic intervention and biomarker development

Dead or alive: animal sampling during Ebola hemorrhagic fever outbreaks in humans

There are currently no widely accepted animal surveillance guidelines for human Ebola hemorrhagic fever (EHF) outbreak investigations to identify potential sources of Ebolavirus (EBOV) spillover into humans and other animals. Animal field surveillance during and following an outbreak has several purposes, from helping identify the specific animal source of a human case to guiding control activities by describing the spatial and temporal distribution of wild circulating EBOV, informing public health efforts, and contributing to broader EHF research questions. Since 1976, researchers have sampled over 10,000 individual vertebrates from areas associated with human EHF outbreaks and tested for EBOV or antibodies. Using field surveillance data associated with EHF outbreaks, this review provides guidance on animal sampling for resource-limited outbreak situations, target species, and in some cases which diagnostics should be prioritized to rapidly assess the presence of EBOV in animal reservoirs. In brief, EBOV detection was 32.7% (18/55) for carcasses (animals found dead) and 0.2% (13/5309) for live captured animals. Our review indicates that for the purposes of identifying potential sources of transmission from animals to humans and isolating suspected virus in an animal in outbreak situations, (1) surveillance of free-ranging non-human primate mortality and morbidity should be a priority, (2) any wildlife morbidity or mortality events should be investigated and may hold the most promise for locating virus or viral genome sequences, (3) surveillance of some bat species is worthwhile to isolate and detect evidence of exposure, and (4) morbidity, mortality, and serology studies of domestic animals should prioritize dogs and pigs and include testing for virus and previous exposure