02298nas a2200229 4500008004100000022001400041245011300055210006900168260000800237300001400245490000700259520149100266653002401757653002501781653001401806653001701820653002401837653001601861100002801877700003601905856012701941 2018 eng d a1387-287700aMulti-faceted role of melatonin in neuroprotection and amelioration of tau aggregates in alzheimer's disease0 aMultifaceted role of melatonin in neuroprotection and ameliorati cMAY a1481-14930 v623 a

Alzheimer's disease (AD) is one of the major age related neurodegenerative diseases whose pathology arises due to the presence of two distinct protein aggregates, viz., amyloid-beta plaques in extracellular matrix and tau neurofibrillary tangles in neurons. Multiple factors play a role in AD pathology, which includes familial mutations, oxidative stress, and post-translational modifications. Melatonin is an endocrine hormone, secreted during darkness, derived from tryptophan, and produced mainly by the pineal gland. It is an amphipathic molecule, which makes it suitable to cross not only blood-brain barrier, but also to enter several other subcellular compartments like mitochondria and endoplasmic reticulum. In this context, the neuroprotective effect of melatonin may be attributed to its role as an antioxidant. Melatonin's pleiotropic function as an antioxidant and neuroprotective agent has been widely studied. However, its direct effect on the aggregation of tau and amyloid-beta needs to be explored. Furthermore, an important aspect of its function is its ability to regulate the process of phosphorylation of tau by affecting the function of kinases and phosphatases. In this review, we are focusing on the pleiotropic function of melatonin on the aspect of its neuroprotective function in tau pathology, which includes antioxidant function, regulation of enzymes, including kinases and enzymes involved in free radical scavenging and mitochondrial protection.

10aAlzheimer's disease10ahyperphosphorylation10amelatonin10amitochondria10aProtein aggregation10atau protein1 aBalmik, Abhishek, Ankur1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/multi-faceted-role-melatonin-neuroprotection-and-amelioration-tau-aggregates-alzheimers01801nas a2200265 4500008004100000022001400041245007700055210006900132260000800201300001100209490000800220520092900228653002201157653001401179653002501193653002901218653002401247653001601271100002901287700002801316700002001344700002601364700003601390856010901426 2019 eng d a0003-986100aBaicalein suppresses repeat tau fibrillization by sequestering oligomers0 aBaicalein suppresses repeat tau fibrillization by sequestering o cOCT a1081190 v6753 a

Alzheimer's disease (AD) is a neurodegenerative disorder caused by protein misfolding, aggregation and accumulation in the brain. A large number of molecules are being screened against these pathogenic proteins but the focus for therapeutics is shifting towards the natural compounds as aggregation inhibitors, mainly due to their minimum adverse effects. Baicalein is a natural compound belonging to the class of flavonoids isolated from the Chinese herb Scutellaria baicalensis. Here we applied fluorescence, absorbance, microscopy, MALDI-TOF spectrophotometry and other biochemical techniques to investigate the interaction between Tau and Baicalein in vitro. We found the aggregation inhibitory properties of Baicalein for the repeat Tau. Overall, the potential of Baicalein in dissolving the preformed Tau oligomers as well as mature fibrils can be of utmost importance in therapeutics for Alzheimer's disease.

10aAlzheimer disease10aBaicalein10aMicrotubule assembly10aPaired helical filaments10aProtein aggregation10atau protein1 aSonawane, Shweta, Kishor1 aBalmik, Abhishek, Ankur1 aBoral, Debjyoti1 aRamasamy, Sureshkumar1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/baicalein-suppresses-repeat-tau-fibrillization-sequestering-oligomers01967nas a2200241 4500008004100000022001400041245008400055210006900139260000900208300001000217490000800227520117000235653002401405653002801429653001401457653002901471653001601500653001601516100001601532700002801548700003601576856011301612 2020 eng d a0141-813000aEffect of melatonin on tau aggregation and tau-mediated cell surface morphology0 aEffect of melatonin on tau aggregation and taumediated cell surf cJUN  a30-390 v1523 a

Aggregation of Microtubule-associated protein Tau and its deposition in the form of neurofibrillary tangles (NFTs) is one of the pathological hallmarks of Alzheimer's disease (AD). Tau aggregation inhibition has been targeted in various studies including natural compounds and synthetic small molecules. Here, we have studied neurohormone- Melatonin against in vitro Tau aggregation and observed its effect on membrane topology, tubulin network and Tau phosphorylation in Neuro2A and N9 cell lines. The aggregation and conformation of Tau was determined by ThT fluorescence and CD spectroscopy respectively. The morphology of Tau aggregates in presence and absence of Melatonin was studied by transmission electron microscopy. Melatonin was found to reduce the formation of higher order oligomeric structures without affecting the overall aggregation kinetics of Tau. Melatonin also modulates and helps to maintain membrane morphology, independent on tubulin network as evidenced by FE-SEM and immunofluorescence analysis. Overall, Melatonin administration shows mild anti-aggregation and cytoprotective effects. (C) 2020 Elsevier B.V. All rights reserved.

10aAlzheimer's disease10aCell surface morphology10amelatonin10aPaired helical filaments10atau protein10aTauopathies1 aDas, Rashmi1 aBalmik, Abhishek, Ankur1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/effect-melatonin-tau-aggregation-and-tau-mediated-cell-surface-morphology02066nas a2200277 4500008004100000022001400041245010400055210006900159260000800228300001100236490000900247520113900256653002401395653001901419653001401438653002901452653001601481653001601497100002801513700001601541700001601557700002801573700002601601700003601627856012501663 2020 eng d a0304-416500aMelatonin interacts with repeat domain of Tau to mediate disaggregation of paired helical filaments0 aMelatonin interacts with repeat domain of Tau to mediate disaggr cMAR a1294670 v18643 a

Tau is the major neuronal protein involved in the stabilization of microtubule assembly. In Alzheimer's disease, Tau self-assembles to form intracellular protein aggregates which are toxic to cells. Various methods have been tried and tested to restrain the aggregation of Tau. Most of the agents tested for this purpose have limitations in their effectiveness and availability to neuronal cells. We have tested melatonin, a neurohormone secreted by pineal gland and a well-known anti-oxidant, for its ability to interact with the repeat domain of Tau using ITC and NMR. In aggregation inhibition and disaggregation studies of repeat Tau, melatonin was found to modulate the aggregation propensity of repeat Tau at a concentration of 5000 mu M and was more effective in dissolving preformed aggregates rather than acting as an aggregation inhibitor. However, there were no major conformational changes in Tau in presence of melatonin as observed by CD spectroscopy. On the basis of our findings, we are proposing a mechanism by which melatonin can interact with the repeat domain of Tau and exhibit its disaggregation effect.

10aAlzheimer's disease10aDisaggregation10amelatonin10aPaired helical filaments10atau protein10aTauopathies1 aBalmik, Abhishek, Ankur1 aDas, Rashmi1 aDangi, Abha1 aGorantla, Nalini, Vijay1 aMarelli, Udaya, Kiran1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/melatonin-interacts-repeat-domain-tau-mediate-disaggregation-paired-helical-filaments02582nas a2200217 4500008004100000020001400041245010300055210006900158260000800227300001600235490000700251520180900258653002602067653001802093653002902111653001602140653001302156100002902169700003602198856013002234 2021 eng d a1949-255300aEpigallocatechin-3-gallate modulates tau post-translational modifications and cytoskeletal network0 aEpigallocatechin3gallate modulates tau posttranslational modific cMAY a1083 - 10990 v123 aBACKGROUND: Alzheimer's disease is a type of dementia denoted by progressive neuronal death due to the accumulation of proteinaceous aggregates of Tau. Post-translational modifications like hyperphosphorylation, truncation, glycation, etc. play a pivotal role in Tau pathogenesis. Glycation of Tau aids in paired helical filament formation and abates its microtubule-binding function. The chemical modulators of Tau PTMs, such as kinase inhibitors and antibody-based therapeutics, have been developed, but natural compounds, as modulators of Tau PTMs are not much explored. MATERIALS AND METHODS: We applied biophysical and biochemical techniques like fluorescence kinetics, oligomerization analysis and transmission electron microscopy to investigate the impact of EGCG on Tau glycation in vitro. The effect of glycation on cytoskeleton instability and its EGCG-mediated rescue were studied by immunofluorescence microscopy in neuroblastoma cells. RESULTS: EGCG inhibited methyl glyoxal (MG)-induced Tau glycation in vitro. EGCG potently inhibited MG-induced advanced glycation endproducts formation in neuroblastoma cells as well modulated the localization of AT100 phosphorylated Tau in the cells. In addition to preventing the glycation, EGCG enhanced actin-rich neuritic extensions and rescued actin and tubulin cytoskeleton severely disrupted by MG. EGCG maintained the integrity of the Microtubule Organizing Center (MTOC) stabilized microtubules by Microtubule-associated protein RP/EB family member 1 (EB1). CONCLUSIONS: We report EGCG, a green tea polyphenol, as a modulator of in vitro methylglyoxal-induced Tau glycation and its impact on reducing advanced glycation end products in neuroblastoma cells. We unravel unprecedented function of EGCG in remodeling neuronal cytoskeletal integrity.10aAlzheimer’s disease10atau glycation10aTau glycation inhibition10atau protein10aTau PTMs1 aSonawane, Shweta, Kishor1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/epigallocatechin-3-gallate-modulates-tau-post-translational-modifications-and-cytoskeletal02228nas a2200217 4500008004100000022001400041245006100055210006100116260000800177300001400185490000700199520152900206653003201735653002901767653002001796653001801816653001601834100003401850700003601884856009001920 2022 eng d a0739-110200aRole of cysteines in accelerating Tau filament formation0 aRole of cysteines in accelerating Tau filament formation cJUN a4366-43750 v403 a

Alzheimer's disease is majorly associated with intracellular accumulation of Tau into paired helical filaments and tangles. The self-aggregated dimeric and oligomeric species of Tau formed are more toxic to neuronal cells and acts as seeds for filament formation. The two cysteine residues and the two hexapeptide regions of full-length Tau play a key role in initialization and filament formation during Tau aggregation. The role of cysteine residues in Tau aggregation has been studied by in-vitro aggregation assay that was measured by Thioflavin S fluorescence to observe the kinetics of aggregation. In this study, we have performed in-vitro aggregation assay with recombinant full-length Tau and the cysteine mutants to understand the mechanism of cysteine independent Tau aggregation. Here, we report that cysteine mutant full-length Tau can aggregate to form filaments under in-vitro conditions. To visualize the polymorphisms of Tau and cysteine mutants under different aggregation conditions anionic cofactor, heparin was employed. Wild-type Tau showed rapid aggregation to form oligomers and filaments. On the other hand, the cysteine mutant delayed the initial Tau aggregation. This indicates the importance of cysteine residues in accelerating initial Tau nucleation for its aggregation. The filament morphology of wild-type and cysteine mutant Tau has been characterized using transmission electron microscopy and high-resolution transmission electron microscopy. Communicated by Ramaswamy H. Sarma

10aHeparin-induced aggregation10aPaired helical filaments10aTau Aggregation10aTau Oligomers10atau protein1 aChidambaram, Hariharakrishnan1 aChinnathambi, Subashchandrabose uhttps://library.ncl.res.in/content/role-cysteines-accelerating-tau-filament-formation