Regional Distribution of Paired Helical Filaments and Normal Tau Proteins in Aging and in Alzheimer's Disease with and without Occipital Lobe Involvement

1992 ◽  
Vol 3 (2) ◽  
pp. 61-69 ◽  
Author(s):  
E.B. Mukaetova-Ladinska ◽  
C.R. Harrington ◽  
R. Hills ◽  
A. O’Sullivan ◽  
M. Roth ◽  
...  
1991 ◽  
Vol 273 (1) ◽  
pp. 127-133 ◽  
Author(s):  
J P Brion ◽  
D P Hanger ◽  
M T Bruce ◽  
A M Couck ◽  
J Flament-Durand ◽  
...  

To investigate the extent to which whole tau proteins, structurally abnormal tau and fragments of tau are incorporated into neurofibrillary tangles in Alzheimer's disease, an immunocytochemical mapping study using a panel of antibodies to several synthetic human tau peptides has been performed. Neurofibrillary tangles were immunolabelled in situ, and paired helical filaments (PHF), the principal structural component of tangles, were immunolabelled after isolation and Pronase treatment. N-Terminal and C-terminal domains of tau were found to be present in tangles in situ. SDS-treated PHF were found to contain most of the C-terminal half of tau and were also labelled by antibodies to ubiquitin. Only some of these PHF were labelled by antisera to tau sequences towards the N-terminus, and this enabled the identification of a region of tau in which proteolytic cleavage may occur. The ultrastructural appearance of the immunolabelling suggested that both the N- and C-terminal domains of tau extend outwards from the axis of PHF. After Pronase treatment. PHF were strongly labelled only by an antiserum to PHF and by the antiserum to the most C-terminal tau synthetic peptide. The latter antiserum also strongly labelled extracellular tangles in situ, whereas these extracellular tangles were poorly labelled by the antisera to the other synthetic peptides. One anti-(tau peptide) serum labelled a population of neurofibrillary tangles in situ only after alkaline phosphatase pretreatment of tissue sections. Our results show that, although peptides along the length of the tau molecule are associated with neurofibrillary tangles in situ, only the C-terminal one-third of the molecule is tightly associated with PHF, since this region of tau is resistant to SDS treatment of PHF. We also report the existence in PHF in situ of a masked tau epitope which is partially unmasked by dephosphorylation. These results are indicative of post-translational changes in tangle-associated tau in degenerating neurons in Alzheimer's disease.


2021 ◽  
Author(s):  
Larissa Rosa Stork ◽  
Lucca Stephani Ribeiro ◽  
Izabella Savergnini Deprá ◽  
Luísa D’Ávila Camargo ◽  
Maria Angélica Santos Novaes

Background: Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by a double proteinopathy: deposition of amyloid-β into plaques and hyperphosphorylation of Tau protein. Objectives: To understand the genetic and molecular aspects of Tau protein and its relationship with Alzheimer’s disease. Methods: We conducted a systematic literature search using Pubmed/ MEDLINE and ClinicalKey databases, applying the descriptors: “Alzheimer Disease” AND “Tau proteins’’ AND Tauopathies, during July and August of 2020. The inclusion criteria were English and Portuguese articles published between 2015 and 2020, with human limited study and free full text, excluding images, books, clinical tests, and narrative reviews. After analyzing titles and abstracts, we selected 12 articles and included 7 additional studies. Results: Mapt, the encoder gene of Tau, is located in the 17q21.3 locus and presents 16 exons that, when transcripted, originates 12 copies of mRNA by alternative splicing and 6 Tau’s isoforms. Tau is a microtubule-associated protein (MAP) responsible for cellular cytoskeleton stabilization and maintenance, promoting neuronal axonal transport. A kinase-phosphatase imbalance turns Tau hyperphosphorylated, disassociating it from tubulin and grouping it into insoluble paired helical filaments, which originates neurofibrillary tangles. The tauopathy’s progress causes neurotransmitter destabilization and neuronal death, inducing AD symptomatic manifestations. Conclusions: Due to the gradual worsening of the disease to more debilitating stages, studies focused on deepening the knowledge of genetic and molecular aspects of Tau protein are viable and promising alternatives to improve the quality of patient’s lives.


2021 ◽  
Vol 22 (17) ◽  
pp. 9207 ◽  
Author(s):  
Jakub Sinsky ◽  
Karoline Pichlerova ◽  
Jozef Hanes

Tau protein plays a critical role in the assembly, stabilization, and modulation of microtubules, which are important for the normal function of neurons and the brain. In diseased conditions, several pathological modifications of tau protein manifest. These changes lead to tau protein aggregation and the formation of paired helical filaments (PHF) and neurofibrillary tangles (NFT), which are common hallmarks of Alzheimer’s disease and other tauopathies. The accumulation of PHFs and NFTs results in impairment of physiological functions, apoptosis, and neuronal loss, which is reflected as cognitive impairment, and in the late stages of the disease, leads to death. The causes of this pathological transformation of tau protein haven’t been fully understood yet. In both physiological and pathological conditions, tau interacts with several proteins which maintain their proper function or can participate in their pathological modifications. Interaction partners of tau protein and associated molecular pathways can either initiate and drive the tau pathology or can act neuroprotective, by reducing pathological tau proteins or inflammation. In this review, we focus on the tau as a multifunctional protein and its known interacting partners active in regulations of different processes and the roles of these proteins in Alzheimer’s disease and tauopathies.


2015 ◽  
Vol 6 (1) ◽  
pp. 214-226 ◽  
Author(s):  
Santosh Jadhav ◽  
Veronika Cubinkova ◽  
Ivana Zimova ◽  
Veronika Brezovakova ◽  
Aladar Madari ◽  
...  

AbstractSynapses are the principal sites for chemical communication between neurons and are essential for performing the dynamic functions of the brain. In Alzheimer’s disease and related tauopathies, synapses are exposed to disease modified protein tau, which may cause the loss of synaptic contacts that culminate in dementia. In recent decades, structural, transcriptomic and proteomic studies suggest that Alzheimer’s disease represents a synaptic disorder. Tau neurofibrillary pathology and synaptic loss correlate well with cognitive impairment in these disorders. Moreover, regional distribution and the load of neurofibrillary lesions parallel the distribution of the synaptic loss. Several transgenic models of tauopathy expressing various forms of tau protein exhibit structural synaptic deficits. The pathological tau proteins cause the dysregulation of synaptic proteome and lead to the functional abnormalities of synaptic transmission. A large body of evidence suggests that tau protein plays a key role in the synaptic impairment of human tauopathies.


Author(s):  
J. Metuzals ◽  
D. F. Clapin ◽  
V. Montpetit

Information on the conformation of paired helical filaments (PHF) and the neurofilamentous (NF) network is essential for an understanding of the mechanisms involved in the formation of the primary lesions of Alzheimer's disease (AD): tangles and plaques. The structural and chemical relationships between the NF and the PHF have to be clarified in order to discover the etiological factors of this disease. We are investigating by stereo electron microscopic and biochemical techniques frontal lobe biopsies from patients with AD and squid giant axon preparations. The helical nature of the lesion in AD is related to pathological alterations of basic properties of the nervous system due to the helical symmetry that exists at all hierarchic structural levels in the normal brain. Because of this helical symmetry of NF protein assemblies and PHF, the employment of structure reconstruction techniques to determine the conformation, particularly the handedness of these structures, is most promising. Figs. 1-3 are frontal lobe biopsies.


Author(s):  
D.F. Clapin ◽  
V.J.A. Montpetit

Alzheimer's disease is characterized by the accumulation of abnormal filamentous proteins. The most important of these are amyloid fibrils and paired helical filaments (PHF). PHF are located intraneuronally forming bundles called neurofibrillary tangles. The designation of these structures as "tangles" is appropriate at the light microscopic level. However, localized domains within individual tangles appear to demonstrate a regular spacing which may indicate a liquid crystalline phase. The purpose of this paper is to present a statistical geometric analysis of PHF packing.


Author(s):  
V.J.A. Montpetit ◽  
S. Dancea ◽  
S.W. French ◽  
D.F. Clapin

A continuing problem in Alzheimer research is the lack of a suitable animal model for the disease. The absence of neurofibrillary tangles of paired helical filaments is the most critical difference in the processes by which the central nervous system ages in most species other than man. However, restricting consideration to single phenomena, one may identify animal models for specific aspects of Alzheimer's disease. Abnormal fibers resembling PHF have been observed in dorsal root ganglia (DRG) neurons of rats in a study of chronic ethanol intoxication and spontaneously in aged rats. We present in this report evidence that PHF-like filaments occur in ethanol-treated rats of young age. In control animals lesions similar in some respects to our observations of cytoskeletal pathology in pyridoxine induced neurotoxicity were observed.Male Wistar BR rats (Charles River Labs) weighing 350 to 400 g, were implanted with a single gastrostomy cannula and infused with a liquid diet containing 30% of total calories as fat plus ethanol or isocaloric dextrose.


2020 ◽  
Vol 20 (12) ◽  
pp. 1059-1073 ◽  
Author(s):  
Ahmad Abu Turab Naqvi ◽  
Gulam Mustafa Hasan ◽  
Md. Imtaiyaz Hassan

Microtubule-associated protein tau is involved in the tubulin binding leading to microtubule stabilization in neuronal cells which is essential for stabilization of neuron cytoskeleton. The regulation of tau activity is accommodated by several kinases which phosphorylate tau protein on specific sites. In pathological conditions, abnormal activity of tau kinases such as glycogen synthase kinase-3 β (GSK3β), cyclin-dependent kinase 5 (CDK5), c-Jun N-terminal kinases (JNKs), extracellular signal-regulated kinase 1 and 2 (ERK1/2) and microtubule affinity regulating kinase (MARK) lead to tau hyperphosphorylation. Hyperphosphorylation of tau protein leads to aggregation of tau into paired helical filaments like structures which are major constituents of neurofibrillary tangles, a hallmark of Alzheimer’s disease. In this review, we discuss various tau protein kinases and their association with tau hyperphosphorylation. We also discuss various strategies and the advancements made in the area of Alzheimer's disease drug development by designing effective and specific inhibitors for such kinases using traditional in vitro/in vivo methods and state of the art in silico techniques.


Author(s):  
Zeba Mueed ◽  
Pankaj Kumar Rai ◽  
Mohammad A. Kamal ◽  
Nitesh Kumar Poddar

Alzheimer’s disease (AD), characterized by abnormally phosphorylated tau, paired helical filaments (PHFs), neurofibrillary tangles (NFTs), deregulated mammalian target of rapamycin (mTOR), Aβ deposits, is a multifactorial disease with sleep disorders being one of the causative agents. Therefore, we have reviewed the literature and have tried to decode the existence of positive feedback, reciprocal and a bidirectional relationship allying between sleep disturbances and AD. Much light has been thrown on the role of tau pathology and amyloid pathology in sleep pathology and its association with AD pathology. We have also discussed the role of melatonin in regulating sleep disorders and AD. The neuroprotective action of melatonin via inhibiting tau hyperphosphorylation and Aβ deposition has also been pondered upon. Moreover, astrocytes involvement in aggravating AD has also been highlighted in this review. Several therapeutic approaches aimed at improving both sleep disorders and AD have been duly discussed such as administration of antidepressants and antihistamines, immunotherapy, metal chelators, melatonin supplementation, light therapy and physical activity. Despite consistent efforts, the complete etiology concerning sleep disorder and AD is still unclear. Therefore, further research is needed to unravel the mechanism involved and also to develop strategies that may help in obstructing AD in its preclinical stage.


Sign in / Sign up

Export Citation Format

Share Document