02270nas a2200217 4500008004100000022001400041245010100055210006900156260000800225300001200233490000700245520150100252653002201753653004401775653002301819653000801842653001601850100002901866700003601895856012101931 2018 eng d a0895-869600aPrion-like propagation of post-translationally modified tau in alzheimer's disease: a hypothesis0 aPrionlike propagation of posttranslationally modified tau in alz cAUG a480-4900 v653 a

The microtubule-associated protein Tau plays a key role in the neuropathology of Alzheimer's disease by forming intracellular neurofibrillary tangles. Tau in the normal physiological condition helps stabilize microtubules and transport. Tau aggregates due to various gene mutations, intracellular insults and abnormal post-translational modifications, phosphorylation being the most important one. Other modifications which alter the function of Tau protein are glycation, nitration, acetylation, methylation, oxidation, etc. In addition to forming intracellular aggregates, Tau pathology might spread in a prion-like manner as revealed by several in vitro and in vivo studies. The possible mechanism of Tau spread can be via bulk endocytosis of misfolded Tau species. The recent studies elucidating this mechanism have mainly focussed on the aggregation and spread of repeat domain of Tau in the cell culture models. Further studies are needed to elucidate the prion-like propagation property of full-length Tau and its aggregates in a more intense manner in vitro as well as in vivo conditions. Varied post-translational modifications can have discrete effects on aggregation propensity of Tau as well as its propagation. Here, we review the prion-like properties of Tau and hypothesize the role of glycation in prion-like properties of Tau. This post-translationally modified Tau might have an enhanced propagation property due to differential properties conferred by the modifications.

10aAlzheimer disease10aPost-translational modifications of tau10aPropagation of tau10aTau10aTauopathies1 aSonawane, Shweta, Kishor1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/prion-propagation-post-translationally-modified-tau-alzheimers-disease-hypothesis02440nas a2200229 4500008004100000022001400041245007500055210006900130260000800199520163100207653002401838653003301862653004501895653001901940653002801959653000801987653002001995653003202015100002802047700003602075856009902111 2020 eng d a0272-434000aAutophagic pathways to clear the tau aggregates in alzheimer's disease0 aAutophagic pathways to clear the tau aggregates in alzheimers di cJUN3 a

Tau is a microtubule-associated protein with an intrinsically unstructured conformation. Tau is subjected to several pathological post-translational modifications (PTMs), leading to its loss of interaction with microtubules and accumulation as neurofibrillary tangles (NFTs) in neurons. Tau aggregates impede functions of endoplasmic reticulum and mitochondria leading to the generation of oxidative stress and in turn amplifying the Tau aggregation. Tau is channelled to chaperones for folding into their native form, which otherwise causes its degradation and clearance. Cellular response triggers the activation of ubiquitin-proteasome system or autophagy to facilitate Tau degradation, based on the PTMs or mutations associated with Tau. Further, autophagy can be selective where Hsc70 interacts with Tau in monomeric, oligomeric and aggregated form and drives its clearance by chaperone-mediated autophagy pathway (CMA). Lysosome-associated membrane proteins-2A (LAMP-2A) is the key player of CMA that recognises Hsc70-Tau complex and triggers the downstream cascade. Thus, it becomes challenging for mutant Tau to be cleared by CMA as it loses its affinity for Hsc70 and LAMP-2A. In such a scenario, Tau might be degraded by macroautophagy otherwise sequestered by aggresomes. Henceforth, the degradation of Tau and its blockage that is associated with various PTMs of Tau would explain the dynamics of Tau degradation or accumulation in AD. Further, unveiling the role of accessory proteins involved in these degradation pathways would help in understanding their loss of function and preventing Tau clearance.

10aAlzheimer's disease10aChaperone-mediated autophagy10aLysosome-associated membrane proteins-2A10aMacroautophagy10aNeurofibrillary tangles10aTau10aTau degradation10aUbiquitin-proteasome system1 aGorantla, Nalini, Vijay1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/autophagic-pathways-clear-tau-aggregates-alzheimers-disease02674nas a2200229 4500008004100000245012800041210006900169260000800238300000800246490000700254520187200261653002402133653002002157653001602177653001402193653001102207653000802218100003402226700001602260700003602276856013202312 2020 eng d00aInteraction of Tau with the chemokine receptor, CX3CR1 and its effect on microglial activation, migration and proliferation0 aInteraction of Tau with the chemokine receptor CX3CR1 and its ef cSEP a1090 v103 a

Alzheimer's disease (AD) is a neurodegenerative disease that leads to progressive loss of memory and dementia. The pathological hallmarks of AD include extracellular accumulation of amyloid-beta peptides forming senile plaques and intracellular accumulation of Tau oligomers and filamentous species. Tau is a microtubule-binding protein that stabilizes tubulin to form microtubules under physiological condition. In AD/ pathological condition, Tau detaches from microtubules and aggregates to form oligomers of different sizes and filamentous species such as paired helical filaments. Microglia are the resident brain macrophages that are involved in the phagocytosis of microbes, cellular debris, misfolded and aggregated proteins. Chemokine receptor, CX3CR1 is mostly expressed on microglia and is involved in maintaining the microglia in a quiescent state by binding to its ligand, fractalkine (CX3CL1), which is expressed in neurons as both soluble or membrane-bound state. Hence, under physiological conditions, the CX3CR1/CX3CL1 axis plays a significant role in maintaining the central nervous system (CNS) homeostasis. Further, CX3CR1/CX3CL1 signalling is involved in the synthesis of anti-inflammatory cytokines and also has a significant role in cytoskeletal rearrangement, migration, apoptosis and proliferation. In AD brain, the expression level of fractalkine is reduced, and hence Tau competes to interact with its receptor, CX3CR1. In microglia, phagocytosis and internalization of extracellular Tau species occurs in the presence of a chemokine receptor, CX3CR1 which binds directly to Tau and promotes its internalization. In this review, the pathophysiological roles of CX3CR1/fractalkine signalling in microglia and neurons at different stages of Alzheimer's disease and the possible role of CX3CR1/Tau signalling has been widely discussed.

10aAlzheimer's disease10aCX3CR1 receptor10aFractalkine10amicroglia10aNeuron10aTau1 aChidambaram, Hariharakrishnan1 aDas, Rashmi1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/interaction-tau-chemokine-receptor-cx3cr1-and-its-effect-microglial-activation-migration-and01956nas a2200253 4500008004100000022001400041245007600055210006900131260000900200300001400209490000800223520116500231653001601396653002401412653001101436653001501447653002001462653000801482100002801490700001601518700002501534700003601559856010701595 2020 eng d a0141-813000aTransition metal nickel prevents Tau aggregation in Alzheimer's disease0 aTransition metal nickel prevents Tau aggregation in Alzheimers d cAUG  a1359-13650 v1563 a

Alzheimer's disease is the leading cause of dementia, effecting majority of aged people worldwide. The multifaceted effectors of Alzheimer's disease primarily include Tau, amyloid-beta along with hyper activation of kinases, oxidative stress and mutations etc., makes it challenging to design therapeutics. Tau is a microtubule-associating protein, which is subjected to cellular stress resulting in the formation of neurofibrillary tangles, leading to loss of affinity for microtubules. This causes loss of microtubule stability and in turn alters axonal integrity. In the present work, emphasis towards understanding interaction of nickel with Tau was made. Metals such as iron, zinc, copper and lead etc., are known to modulate Tau conformation and enhance its aggregation. Our results showed the deliverance of Tau aggregation by nickel and its synthetic morpholine conjugate. Nickel prevents aggregation by inducing degradation of Tau as evidenced by SDS-PAGE and TEM. Nickel and the synthetic conjugate being non toxic to neuro2a cells and prevent Tau aggregation, might direct these complexes to overcome AD. (C) 2019 Published by Elsevier B.V.

10aAggregation10aAlzheimer's disease10ametals10aMorpholine10aNickel chloride10aTau1 aGorantla, Nalini, Vijay1 aDas, Rashmi1 aBalaraman, Ekambaram1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/transition-metal-nickel-prevents-tau-aggregation-alzheimers-disease02652nas a2200277 4500008004100000245011100041210006900152260000900221300000700230490000700237520177100244653001002015653001702025653001002042653001602052653002202068653002002090653001202110653001402122653000802136653001602144100002802160700002902188700003602217856012102253 2021 eng d00aExtracellular HDAC6 ZnF UBP domain modulates the actin network and post-translational modifications of Tau0 aExtracellular HDAC6 ZnF UBP domain modulates the actin network a cMAY  a490 v193 a

Background: Microtubule-associated protein Tau undergoes aggregation in Alzheimer`s disease (AD) and a group of other related diseases collectively known as Tauopathies. In AD, Tau forms aggregates, which are deposited intracellularly as neurofibrillary tangles. Histone deacetylase-6 (HDAC6) plays an important role in aggresome formation, where it recruits polyubiquitinated aggregates to the motor protein dynein. Methods: Here, we have studied the effects of HDAC6 ZnF UBP on Tau phosphorylation, ApoE localization, GSK-3 beta regulation and cytoskeletal organization in neuronal cells by immunocytochemical analysis. This analysis reveals that the cell exposure to the UBP-type zinc finger domain of HDAC6 (HDAC6 ZnF UBP) can modulate Tau phosphorylation and actin cytoskeleton organization. Results: HDAC6 ZnF UBP treatment to cells did not affect their viability and resulted in enhanced neurite extension and formation of structures similar to podosomes, lamellipodia and podonuts suggesting the role of this domain in actin re-organization. Also, HDAC6 ZnF UBP treatment caused increase in nuclear localization of ApoE and tubulin localization in microtubule organizing centre (MTOC). Therefore, our studies suggest the regulatory role of this domain in different aspects of neurodegenerative diseases. Upon HDAC6 ZnF UBP treatment, inactive phosphorylated form of GSK-3 beta increases without any change in total GSK-3 beta level. Conclusions: HDAC6 ZnF UBP was found to be involved in cytoskeletal re-organization by modulating actin dynamics and tubulin localization. Overall, our study suggests that ZnF domain of HDAC6 performs various regulatory functions apart from its classical function in aggresome formation in protein misfolding diseases.

10aActin10aCytoskeleton10aHDAC610aMicrotubule10aneurodegeneration10aPhosphorylation10aPodonut10aPodosomes10aTau10aTauopathies1 aBalmik, Abhishek, Ankur1 aSonawane, Shweta, Kishor1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/extracellular-hdac6-znf-ubp-domain-modulates-actin-network-and-post-translational02404nas a2200217 4500008004100000245009700041210006900138260000900207300000700216490000700223520165600230653001601886653001601902653001601918653002301934653003701957653000801994100002802002700003602030856012002066 2021 eng d00aMethylation as a key regulator of Tau aggregation and neuronal health in Alzheimer's disease0 aMethylation as a key regulator of Tau aggregation and neuronal h cMAY  a510 v193 a

Neurodegenerative diseases like Alzheimer's, Parkinson's and Huntington's disease involves abnormal aggregation and accumulation of toxic proteins aggregates. Post-translational modifications (PTMs) of the causative proteins play an important role in the etiology of disease as they could either slow down or accelerate the disease progression. Alzheimer disease is associated with the aggregation and accumulation of two major protein aggregates-intracellular neurofibrillary tangles made up of microtubule-associated protein Tau and extracellular Amyloid-beta plaques. Post-translational modifications are important for the regulation of Tau`s function but an imbalance in PTMs may lead to abnormal Tau function and aggregation. Tau methylation is one of the important PTM of Tau in its physiological state. However, the methylation signature on Tau lysine changes once it acquires pathological aggregated form. Tau methylation can compete with other PTMs such as acetylation and ubiquitination. The state of PTM at these sites determines the fate of Tau protein in terms of its function and stability. The global methylation in neurons, microglia and astrocytes are involved in multiple cellular functions involving their role in epigenetic regulation of gene expression via DNA methylation. Here, we have discussed the effect of methylation on Tau function in a site-specific manner and their cross-talk with other lysine modifications. We have also elaborated the role of methylation in epigenetic aspects and neurodegenerative conditions associated with the imbalance in methylation metabolism affecting global methylation state of cells.

10aAggregation10aEpigenetics10amethylation10aMethyltransferases10apost-translational modifications10aTau1 aBalmik, Abhishek, Ankur1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/methylation-key-regulator-tau-aggregation-and-neuronal-health-alzheimers-disease02456nas a2200241 4500008004100000022001400041245015600055210006900211260000800280300001100288490000800299520165300307653002601960653002001986653001402006653001102020653001702031653000802048100003402056700001602090700003602106856007202142 2022 eng d a0171-933500aG-protein coupled purinergic P2Y12 receptor interacts and internalizes TauRD-mediated by membrane-associated actin cytoskeleton remodeling in microglia0 aGprotein coupled purinergic P2Y12 receptor interacts and interna cAPR a1512010 v1013 aIn Alzheimer’s disease, the microtubule-associated protein, Tau misfolds to form aggregates and filaments in the intra- and extracellular region of neuronal cells. Microglial cells are the resident brain macrophage cells involved in constant surveillance and activated by the extracellular deposits. Purinergic receptors are involved in the chemotactic migration of microglial cells towards the site of inflammation. From our recent study, we have observed that the microglial P2Y12 receptor is involved in phagocytosis of full-length Tau species such as monomers, oligomers and aggregates by actin-driven chemotaxis. This study shows the interaction of repeat-domain of Tau (TauRD) with the microglial P2Y12 receptor and the corresponding residues for interaction have been analysed by various in-silico approaches. In the cellular studies, TauRD was found to interact with microglial P2Y12R and induces its cellular expression confirmed by co-immunoprecipitation and western blot analysis. Furthermore, the P2Y12R-mediated TauRD internalization has demonstrated activation of microglia with an increase in the Iba1 level, and TauRD becomes accumulated at the peri-nuclear region for the degradation. Similarly, immunofluorescence microscopic studies emphasized that TauRD is phagocytosed by microglial P2Y12R via the membrane-associated actin remodeling as filopodia extension. Upon internalization, we have demonstrated the P2Y12R signaling-mediated degradation of accumulated TauRD by lysosomal pathway. Altogether, microglial P2Y12R interacts with TauRD and mediates directed migration and activation for its internalization and degradation.10aAlzheimer’s disease10aInternalization10amicroglia10aP2Y12R10aPhagocytosis10aTau1 aChidambaram, Hariharakrishnan1 aDas, Rashmi1 aChinnathambi, Subashchandrabose uhttps://www.sciencedirect.com/science/article/pii/S017193352200004801984nas a2200241 4500008004100000022001400041245007200055210006900127260000800196300001100204490000900215520126100224653001001485653001701495653001001512653001701522653001701539653000801556653001901564100002001583700003601603856010301639 2022 eng d a0167-488900aHistone deacetylase-6 modulates Tau function in Alzheimer's disease0 aHistone deacetylase6 modulates Tau function in Alzheimers diseas cAUG a1192750 v18693 a

Alzheimer's disease (AD), one of the major tauopathies, is multifactorial with a massive demand for disease modifying treatments rather than symptom management. An AD-affected neuron shows Tau depositions generated due to overload on the proteostasis machinery of the cell and/or abnormal post-translational modifications on Tau protein. Loss of memory or dementia is the most significant concern in AD, occurring due to the loss of neurons and the connections between them. In a healthy brain, neurons interact with the environment and each other through extensions and migratory structures. It can thus be safe to assume that Tau depositions affect these growth structures in neurons. A Histone Deacetylase, HDAC6, has shown elevated levels in AD while also demonstrating direct interaction with the Tau protein. HDAC6 interacts with multiple proteins in the cell and is possibly involved in various signalling pathways. Its deacetylase activity has been a point of controversy in AD; however other functional domains remain unexplored. This review highlights the beneficial potential of HDAC6 in AD in mediating both Tau proteostasis and cytoskeletal rewiring for the neuritic extensions through its Ubiquitin Binding domain (HDAC6 ZnF UBP).

10aActin10aCytoskeleton10aHDAC610aMicrotubules10aProteostasis10aTau10aZnF UBP domain1 aQureshi, Tazeen1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/histone-deacetylase-6-modulates-tau-function-alzheimers-disease