scholarly journals Tau in the brain interstitial fluid is fragmented and seeding-competent

2020 ◽  
Author(s):  
Erica Barini ◽  
Gudrun Plotzky ◽  
Yulia Mordashova ◽  
Jonas Hoppe ◽  
Esther Rodriguez-Correa ◽  
...  

SUMMARYIn Alzheimer disease, Tau pathology is thought to propagate from cell to cell throughout interconnected brain areas. However, the forms of Tau released into the brain interstitial fluid (ISF) in vivo during the development of Tauopathy and their pathological relevance remain unclear. Combining in vivo microdialysis and biochemical analysis, we find that human Tau (hTau) present in brain ISF is truncated and comprises at least 10 distinct fragments spanning the entire Tau protein. The fragmentation pattern is similar across different Tau transgenic models, pathological stages and brain areas. ISF hTau concentration decreases during Tauopathy progression, while its phosphorylation increases. ISF from mice with established Tauopathy induces Tau aggregation in HEK293-Tau biosensor cells and notably, only a small fraction of Tau, separated by ultracentrifugation, is seeding competent. These results indicate that only a subset of Tau accounts for ISF seeding competence and have the potential to contribute to the propagation of Tau pathology.Graphical abstractHighlights✓In transgenic mice, interstitial fluid comprises several Tau fragments spanning the entire Tau sequence.✓Interstitial fluid Tau concentration decreases with Tauopathy progression, while phosphorylation increases.✓Only interstitial fluid from mice with established Tauopathy is seeding competent in vitro.✓Interstitial fluid seeding competence is driven by less soluble, aggregated and phosphorylated Tau species.In BriefBarini et al. show that in the brain interstitial fluid of Tau transgenic mice, truncated Tau decreases, while its phosphorylation increases during the progression of pathology. A subset of less soluble, aggregated and phosphorylated ISF Tau induces Tau aggregation in cells.

2013 ◽  
Vol 8 (1) ◽  
pp. 13 ◽  
Author(s):  
Jason D Ulrich ◽  
Jack M Burchett ◽  
Jessica L Restivo ◽  
Dorothy R Schuler ◽  
Philip B Verghese ◽  
...  

1992 ◽  
Vol 81 (2-3) ◽  
pp. 143-152 ◽  
Author(s):  
Terasaki Tetsuya ◽  
Deguchi Yoshiharu ◽  
Kasama Yuko ◽  
William M. Pardridge ◽  
Tsuji Akira

Author(s):  
Eugene Bok ◽  
Eunju Leem ◽  
Bo-Ram Lee ◽  
Ji Min Lee ◽  
Chang Jae Yoo ◽  
...  

Abnormal accumulation of misfolded tau aggregates is a pathological hallmark of various tauopathies including Alzheimer’s disease (AD). Although tau is a cytosolic microtubule-associated protein enriched in neurons, it is also found in extracellular milieu, such as interstitial fluid, cerebrospinal fluid, and blood. Accumulating evidence showed that pathological tau spreads along anatomically connected areas in the brain through intercellular transmission and templated misfolding, thereby inducing neurodegeneration and cognitive dysfunction. In line with this, the spatiotemporal spreading of tau pathology is closely correlated with cognitive decline in AD patients. Although the secretion and uptake of tau involve multiple different pathways depending on tau species and cell types, a growing body of evidence suggested that tau is largely secreted in a vesicle-free forms. In this regard, the interaction of vesicle-free tau with membrane is gaining growing attention due to its importance for both of tau secretion and uptake as well as aggregation. Here, we review the recent literature on the mechanisms of the tau-membrane interaction and highlights the roles of lipids and proteins at the membrane in the tau-membrane interaction as well as tau aggregation.


2011 ◽  
Vol 31 (37) ◽  
pp. 13110-13117 ◽  
Author(s):  
K. Yamada ◽  
J. R. Cirrito ◽  
F. R. Stewart ◽  
H. Jiang ◽  
M. B. Finn ◽  
...  

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Tadafumi Hashimoto ◽  
Daisuke Fujii ◽  
Yasushi Naka ◽  
Mayu Kashiwagi-Hakozaki ◽  
Yuko Matsuo ◽  
...  

AbstractMassive deposition of amyloid β peptides (Aβ) as senile plaques (SP) characterizes the brain pathology of Alzheimer’s disease (AD). SPs exhibit a variety of morphologies, although little is known about the SP components that determine their morphology. Collagenous Alzheimer amyloid plaque component (CLAC) is one of the major non-Aβ proteinaceous components of SP amyloid in AD brains. Here we show that overexpression of CLAC precursor (CLAC-P) in the brains of APP transgenic mice results in a significant remodeling of amyloid pathology, i.e., reduction in diffuse-type amyloid plaques and an increase in compact plaques laden with thioflavin S-positive amyloid cores. In vivo microdialysis revealed a significant decrease in Aβ in the brain interstitial fluid of CLAC-P/APP double transgenic mice compared with APP transgenic mice. These findings implicate CLAC in the compaction of Aβ in amyloid plaques and the brain dynamics of Aβ.


2021 ◽  
Vol 12 ◽  
Author(s):  
Antonio Valencia ◽  
Veronica L. Reinhart Bieber ◽  
Bekim Bajrami ◽  
Galina Marsh ◽  
Stefan Hamann ◽  
...  

Acetylation of tau protein is dysregulated in Alzheimer's Disease (AD). It has been proposed that acetylation of specific sites in the KXGS motif of tau can regulate phosphorylation of nearby residues and reduce the propensity of tau to aggregate. Histone deacetylase 6 (HDAC6) is a cytoplasmic enzyme involved in deacetylation of multiple targets, including tau, and it has been suggested that inhibition of HDAC6 would increase tau acetylation at the KXGS motifs and thus may present a viable therapeutic approach to treat AD. To directly test the contribution of HDAC6 to tau pathology, we intracerebroventricularly injected an antisense oligonucleotide (ASO) directed against HDAC6 mRNA into brains of P301S tau mice (PS19 model), which resulted in a 70% knockdown of HDAC6 protein in the brain. Despite a robust decrease in levels of HDAC6, no increase in tau acetylation was observed. Additionally, no change of tau phosphorylation or tau aggregation was detected upon the knockdown of HDAC6. We conclude that HDAC6 does not impact tau pathology in PS19 mice.


2016 ◽  
Vol 21 (2) ◽  
pp. 28-37
Author(s):  
Oscar Solís-Salgado ◽  
José Luis López-Payares ◽  
Mauricio Ayala-González

Las vías de drenaje solutos del sistema nervioso central (SNC) participan en el recambio de liquido intersticial con el líquido cefalorraquídeo (LIT-LCR), generando un estado de homeostasis. Las alteraciones dentro de este sistema homeostático afectará la eliminación de solutos del espacio intersticial (EIT) como el péptido βa y proteína tau, los cuales son sustancias neurotóxicas para el SNC. Se han utilizado técnicas experimentales para poder analizar el intercambio LIT-LCR, las cuales revelan que este intercambio tiene una estructura bien organizada. La eliminación de solutos del SNC no tiene una estructura anatómica propiamente, se han descubierto vías de eliminación de solutos a través de marcadores florecentes en el espacio subaracnoideo, cisternas de la base y sistema ventricular que nos permiten observar una serie de vías ampliamente distribuidas en el cerebro. El LCR muestra que tiene una función linfática debido a su recambio con el LIT a lo largo de rutas paravasculares. Estos espacios que rodean la superficie arterial así como los espacios de Virchow-Robin y el pie astrocitico junto con la AQP-4, facilitan la entrada de LCR para-arterial y el aclaramiento de LIT para-venoso dentro del cerebro. El flujo y dirección que toma el LCR por estas estructuras, es conducido por la pulsación arterial. Esta función será la que finalmente llevara a la eliminación de estas sustancias neurotóxicas. En base a la dependencia de este flujo para la eliminación de sustancias se propone que el sistema sea llamado “ la Vía Glinfática”. La bibliografía así como las limitaciones que se encuentran en esta revisión están dadas por la metodología de búsqueda que ha sido realizada principalmente en PubMed utilizando los siguientes términos Mesh: Cerebral Arterial Pulsation, the brain via paravascular, drainage of amyloid-beta, bulk flow of brain interstitial fluid, radiolabeled polyethylene glycols and albumin, amyloid-β, the perivascular astroglial sheath, Brain Glymphatic Transport.


Author(s):  
Tomas T. Roos ◽  
Megg G. Garcia ◽  
Isak Martinsson ◽  
Rana Mabrouk ◽  
Bodil Israelsson ◽  
...  

AbstractThe amyloid-beta peptide (Aβ) is thought to have prion-like properties promoting its spread throughout the brain in Alzheimer’s disease (AD). However, the cellular mechanism(s) of this spread remains unclear. Here, we show an important role of intracellular Aβ in its prion-like spread. We demonstrate that an intracellular source of Aβ can induce amyloid plaques in vivo via hippocampal injection. We show that hippocampal injection of mouse AD brain homogenate not only induces plaques, but also damages interneurons and affects intracellular Aβ levels in synaptically connected brain areas, paralleling cellular changes seen in AD. Furthermore, in a primary neuron AD model, exposure of picomolar amounts of brain-derived Aβ leads to an apparent redistribution of Aβ from soma to processes and dystrophic neurites. We also observe that such neuritic dystrophies associate with plaque formation in AD-transgenic mice. Finally, using cellular models, we propose a mechanism for how intracellular accumulation of Aβ disturbs homeostatic control of Aβ levels and can contribute to the up to 10,000-fold increase of Aβ in the AD brain. Our data indicate an essential role for intracellular prion-like Aβ and its synaptic spread in the pathogenesis of AD.


Sign in / Sign up

Export Citation Format

Share Document