scholarly journals Keeping the ageing brain wired: a role for purine signalling in regulating cellular metabolism in oligodendrocyte progenitors

2021 ◽  
Author(s):  
Andrea D. Rivera ◽  
Irene Chacon-De-La-Rocha ◽  
Francesca Pieropan ◽  
Maria Papanikolau ◽  
Kasum Azim ◽  
...  
Keyword(s):  
Chondroitin Sulphate ◽  
Adult Brain ◽  
Receptor Subtype ◽  
Proliferating Cells ◽  
Specific Expression ◽  
Self Renewal ◽  
Neuronal Signalling ◽  
Age Related ◽  
Neuronal Connections ◽  
Key Factor

AbstractWhite matter (WM) is a highly prominent feature in the human cerebrum and is comprised of bundles of myelinated axons that form the connectome of the brain. Myelin is formed by oligodendrocytes and is essential for rapid neuronal electrical communication that underlies the massive computing power of the human brain. Oligodendrocytes are generated throughout life by oligodendrocyte precursor cells (OPCs), which are identified by expression of the chondroitin sulphate proteoglycan NG2 (Cspg4), and are often termed NG2-glia. Adult NG2+ OPCs are slowly proliferating cells that have the stem cell–like property of self-renewal and differentiation into a pool of ‘late OPCs’ or ‘differentiation committed’ OPCs(COPs) identified by specific expression of the G-protein-coupled receptor GPR17, which are capable of differentiation into myelinating oligodendrocytes. In the adult brain, these reservoirs of OPCs and COPs ensure rapid myelination of new neuronal connections formed in response to neuronal signalling, which underpins learning and cognitive function. However, there is an age-related decline in myelination that is associated with a loss of neuronal function and cognitive decline. The underlying causes of myelin loss in ageing are manifold, but a key factor is the decay in OPC ‘stemness’ and a decline in their replenishment of COPs, which results in the ultimate failure of myelin regeneration. These changes in ageing OPCs are underpinned by dysregulation of neuronal signalling and OPC metabolic function. Here, we highlight the role of purine signalling in regulating OPC self-renewal and the potential importance of GPR17 and the P2X7 receptor subtype in age-related changes in OPC metabolism. Moreover, age is the main factor in the failure of myelination in chronic multiple sclerosis and myelin loss in Alzheimer’s disease, hence understanding the importance of purine signalling in OPC regeneration and myelination is critical for developing new strategies for promoting repair in age-dependent neuropathology.

scholarly journals Tissue-specific expression of the heat shock protein HSP27 during Drosophila melanogaster development.

1990 ◽  
Vol 111 (3) ◽  
pp. 817-828 ◽  
Author(s):  
D Pauli ◽  
C H Tonka ◽  
A Tissieres ◽  
A P Arrigo
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Stress Protein ◽  
Pupal Stage ◽  
Adult Brain ◽  
Proliferating Cells ◽  
Specific Expression ◽  
The Central Nervous System

The alpha-crystallin-related heat shock (stress) protein hsp27 is expressed in absence of heat shock during Drosophila melanogaster development. Here, we describe the tissue distribution of this protein using an immunoaffinity-purified antibody. In embryos, hsp27 translated from maternal RNA is uniformly distributed, except in the yolk. During the first, second, and early third larval stages, hsp27 expression is restricted to the brain and the gonads. These tissues are characterized by a high level of proliferating cells. In late third instar larvae and early pupae, in addition to the central nervous system and the gonads, all the imaginal discs synthesize hsp27. The disc expression seems restricted to the beginning of their differentiation since it disappears during the second half of the pupal stage: no more hsp27 is observed in the disc-derived adult organs. In adults, hsp27 is still present in some regions of the central nervous system, and is also expressed in the male and female germ lines where it accumulates in mature sperm and oocytes. The transcript and the protein accumulate in oocytes since the onset of vitellogenesis with a uniform distribution similar to that found in embryos. The adult germ lines transcribe hsp27 gene while no transcript is detected in the late pupal and adult brain. These results suggest multiple roles of hsp27 during Drosophila development which may be related to both the proliferative and differentiated states of the tissues.

scholarly journals Intercellular Transfer of Mitochondria between Senescent Cells through Cytoskeleton-Supported Intercellular Bridges Requires mTOR and CDC42 Signalling

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Hannah E. Walters ◽  
Lynne S. Cox
Keyword(s):  
Cell Communication ◽  
Time Lapse ◽  
Proliferating Cells ◽  
Intercellular Bridges ◽  
Telomere Attrition ◽  
Acute Response ◽  
Age Related ◽  
Cell Age ◽  
Organelle Transfer ◽  
Key Factor

Cellular senescence is a state of irreversible cell proliferation arrest induced by various stressors including telomere attrition, DNA damage, and oncogene induction. While beneficial as an acute response to stress, the accumulation of senescent cells with increasing age is thought to contribute adversely to the development of cancer and a number of other age-related diseases, including neurodegenerative diseases for which there are currently no effective disease-modifying therapies. Non-cell-autonomous effects of senescent cells have been suggested to arise through the SASP, a wide variety of proinflammatory cytokines, chemokines, and exosomes secreted by senescent cells. Here, we report an additional means of cell communication utilised by senescent cells via large numbers of membrane-bound intercellular bridges—or tunnelling nanotubes (TNTs)—containing the cytoskeletal components actin and tubulin, which form direct physical connections between cells. We observe the presence of mitochondria in these TNTs and show organelle transfer through the TNTs to adjacent cells. While transport of individual mitochondria along single TNTs appears by time-lapse studies to be unidirectional, we show by differentially labelled co-culture experiments that organelle transfer through TNTs can occur between different cells of equivalent cell age, but that senescent cells, rather than proliferating cells, appear to be predominant mitochondrial donors. Using small molecule inhibitors, we demonstrate that senescent cell TNTs are dependent on signalling through the mTOR pathway, which we further show is mediated at least in part through the downstream actin-cytoskeleton regulatory factor CDC42. These findings have significant implications for the development of senomodifying therapies, as they highlight the need to account for local direct cell-cell contacts as well as the SASP in order to treat cancer and diseases of ageing in which senescence is a key factor.

scholarly journals Intercellular transfer of mitochondria between senescent cells through cytoskeleton-supported intercellular bridges requires mTOR and Cdc42 signalling

2020 ◽  
Author(s):  
Hannah Walters ◽  
Lynne S Cox
Keyword(s):  
Cell Communication ◽  
Senescent Cell ◽  
Proliferating Cells ◽  
Intercellular Bridges ◽  
Telomere Attrition ◽  
Acute Response ◽  
Age Related ◽  
Organelle Transfer ◽  
Key Factor ◽  
Direct Cell

AbstractCellular senescence is a state of irreversible cell proliferation arrest induced by various stressors including telomere attrition, DNA damage and oncogene induction. While beneficial as an acute response to stress, accumulation of senescent cells with increasing age is through to contribute adversely to development of cancer and a number of other age-related diseases, including neurodegenerative diseases for which there are currently no effective disease-modifying therapies. Non-cell autonomous effects of senescent cells have been suggested to arise through the SASP, a wide variety of pro-inflammatory cytokines, chemokines and exosomes secreted by senescent cells. Here, we report an additional means of cell communication utilised by senescent cells via large numbers of membrane-bound intercellular bridges - or tunnelling nanotubes (TNTs) - containing the cytoskeletal components actin and tubulin, and which form direct physical connections between cells. We observe the presence of mitochondria in these TNTs, and show organelle transfer through the TNTs to adjacent cells. While transport of individual mitochondria along single TNTs appears unidirectional, we show by differentially labelled co-culture experiments that organelle transfer through TNTs can occur both between different cells within senescent cell populations, and also between senescent and proliferating cells. Using small molecule inhibitors, we demonstrate that senescent cell TNTs are dependent on signalling through the mTOR pathway, which we further show is mediated at least in part through downstream actin-cytoskeleton regulatory factor Cdc42. These findings have significant implications for development of senomodifying therapies, as they highlight the need to account for local direct cell-cell contacts as well as the SASP in order to treat cancer and diseases of ageing in which senescence is a key factor.

scholarly journals Chondroitin 6-sulphate is required for neuroplasticity and memory in ageing

2021 ◽  
Author(s):  
Sujeong Yang ◽  
Sylvain Gigout ◽  
Angelo Molinaro ◽  
Yuko Naito-Matsui ◽  
Sam Hilton ◽  
...  
Keyword(s):  
Chondroitin Sulphate ◽  
Memory Loss ◽  
Memory Deficits ◽  
Long Term Potentiation ◽  
Aged Mice ◽  
Age Related ◽  
Term Potentiation ◽  
Early Memory

AbstractPerineuronal nets (PNNs) are chondroitin sulphate proteoglycan-containing structures on the neuronal surface that have been implicated in the control of neuroplasticity and memory. Age-related reduction of chondroitin 6-sulphates (C6S) leads to PNNs becoming more inhibitory. Here, we investigated whether manipulation of the chondroitin sulphate (CS) composition of the PNNs could restore neuroplasticity and alleviate memory deficits in aged mice. We first confirmed that aged mice (20-months) showed memory and plasticity deficits. They were able to retain or regain their cognitive ability when CSs were digested or PNNs were attenuated. We then explored the role of C6S in memory and neuroplasticity. Transgenic deletion of chondroitin 6-sulfotransferase (chst3) led to a reduction of permissive C6S, simulating aged brains. These animals showed very early memory loss at 11 weeks old. Importantly, restoring C6S levels in aged animals rescued the memory deficits and restored cortical long-term potentiation, suggesting a strategy to improve age-related memory impairment.

scholarly journals A Review on Recent Advancement on Age-Related Hearing Loss: The Applications of Nanotechnology, Drug Pharmacology, and Biotechnology

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1041
Author(s):  
Jacqueline Chester ◽  
Edan Johnston ◽  
Daniel Walker ◽  
Melissa Jones ◽  
Corina Mihaela Ionescu ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Bile Acid ◽  
Hearing Aids ◽  
Stria Vascularis ◽  
Cellular Damage ◽  
Relevant Evidence ◽  
Neuronal Signalling ◽  
Age Related ◽  
Recent Advancement ◽  
Age Related Hearing Loss

Aging is considered a contributing factor to many diseases such as cardiovascular disease, Alzheimer’s disease, and hearing loss. Age-related hearing loss, also termed presbycusis, is one of the most common sensory impairments worldwide, affecting one in five people over 50 years of age, and this prevalence is growing annually. Associations have emerged between presbycusis and detrimental health outcomes, including social isolation and mental health. It remains largely untreatable apart from hearing aids, and with no globally established prevention strategies in the clinical setting. Hence, this review aims to explore the pathophysiology of presbycusis and potential therapies, based on a recent advancement in bile acid-based bio-nanotechnologies. A comprehensive online search was carried out using the following keywords: presbycusis, drugs, hearing loss, bile acids, nanotechnology, and more than 150 publications were considered directly relevant. Evidence of the multifaceted oxidative stress and chronic inflammation involvement in cellular damage and apoptosis that is associated with a loss of hair cells, damaged and inflamed stria vascularis, and neuronal signalling loss and apoptosis continues to emerge. New robust and effective therapies require drug delivery deeper into the various layers of the cochlea. Bile acid-based nanotechnology has gained wide interest in its permeation-enhancing ability and potential for numerous applications in treating presbycusis.

Activity and expression pattern of cyclin-dependent kinase 5 in the embryonic mouse nervous system

Development ◽  
1993 ◽  
Vol 119 (4) ◽  
pp. 1029-1040 ◽  
Author(s):  
L.H. Tsai ◽  
T. Takahashi ◽  
V.S. Caviness ◽  
E. Harlow
Keyword(s):  
Nervous System ◽  
Cell Division ◽  
Cell Division Cycle ◽  
Adult Brain ◽  
Cyclin Dependent Kinase ◽  
Proliferating Cells ◽  
Embryonic Mouse ◽  
Postmitotic Neurons ◽  
Cyclin Dependent Kinase 5 ◽  
Expression And Activity

Cyclin-dependent kinase 5 (cdk5) was originally isolated on the basis of its close primary sequence homology to the human cdc2 serine/threonine kinase, the prototype of the cyclin-dependent kinases. While kinase activities of both cdc2 and cdk2 are detected in proliferating cells and are essential for cells to progress through the key transition points of the cell cycle, cdk5 kinase activity has been observed only in lysates of adult brain. In this study, we compared the activity and expression of cdk5 with that of cdc2 and cdk2 in the embryonic mouse forebrain. The expression and activity of cdk5 increased progressively as increasing numbers of cells exited the proliferative cycle. In contrast, the expression and activity of cdc2 and cdk2 were maximum at gestational day 11 (E11) when the majority of cells were proliferating and fell to barely detectable levels at E17 at the end of the cytogenetic period. Immunohistochemical studies showed that cdk5 is expressed in postmitotic neurons but not in glial cells or mitotically active cells. Expression of cdk5 was concentrated in fasciculated axons of postmitotic neurons. In contrast to other cell division cycle kinases to which it is closely related, cdk5 appears not to be expressed in dividing cells in the developing brain. These observations suggest that cdk5 may have a role in neuronal differentiation but not in the cell division cycle in the embryonic nervous system.

HEAT SHOCK PROTEIN 90 (90) IN AGE-DEPENDENT CHANGES IN THE NUMBER OF FIBROBLASTS IN HUMAN SKIN

2020 ◽  
pp. 40-45
Author(s):  
А. Г. Гунин ◽  
Н. Н. Голубцова ◽  
Н. К. Корнилова
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Heat Shock Protein 90 ◽  
Nuclear Antigen ◽  
Positive Staining ◽  
Proliferating Cells ◽  
Age Related ◽  
Age Dependent ◽  
Human Dermis ◽  
Hsp 90

Целью работы стало исследование содержания белка теплового шока 90 ( HSP 90) в фибробластах дермы человека от эмбрионального развития и до глубокой старости (от 20 нед беременности до 85 лет), а также определение значения HSP 90 для возрастных изменений численности фибробластов в дерме человека. HSP 90, ядерный антиген пролиферирующих клеток ( PCNA ) выявляли в срезах кожи непрямым иммуногистохимическим методом. Результаты показали, что в коже человека от 20 нед беременности до 20 лет доля фибробластов дермы с положительной окраской на HSP 90 остается постоянной. С 21 года до 60 лет наблюдают планомерное уменьшение доли фибробластов дермы, имеющих положительную окраску на HSP 90. У людей 61-85 лет происходит резкое увеличение доли фибробластов дермы с положительной окраской на HSP 90. Возрастные изменения содержания HSP 90 положительных фибробластов в дерме статистически не связаны с возрастным уменьшением общего количества и доли PCNA -положительных фибробластов в дерме. The aim of this work was to examine the content of heat shock protein 90 ( HSP 90) in fibroblasts of human dermis from the development until deep aging (from 20 weeks of pregnancy until 85 years old), and defining of a role of HSP 90 in age-dependent changes in the number of fibroblasts in the dermis. HSP 90, proliferating cells nuclear antigen ( PCNA ) were detected with indirect immunohistochemical technique. Results showed that a portion of fibroblasts with positive staining for HSP 90 in the dermis is not changed from 20 weeks of development to 20 years old. Percent of HSP 90 positive fibroblasts in dermis is decreased from 21 to 60 years old. From 61 year, the number of HSP 90 positive fibroblasts in dermis is increased. Age-related changes in the number of HSP 90 positive fibroblasts is not statistically associated with an age-related decrease in a total number and percent of PCNA positive fibroblasts the dermis.

scholarly journals Peptide location fingerprinting reveals modification-associated biomarkers of ageing in human tissue proteomes

2020 ◽  
Author(s):  
Matiss Ozols ◽  
Alexander Eckersley ◽  
Kieran T Mellody ◽  
Venkatesh Mallikarjun ◽  
Stacey Warwood ◽  
...  
Keyword(s):  
Structural Modification ◽  
Protein Structures ◽  
Cytoskeletal Proteins ◽  
Structural Modifications ◽  
Location Fingerprinting ◽  
Age Related ◽  
Analysis Technique ◽  
Key Factor ◽  
Aged Skin ◽  
Novel Biomarkers

AbstractAlthough dysfunctional protein homeostasis (proteostasis) is a key factor in many age-related diseases, the untargeted identification of structural modifications in proteins remains challenging. Peptide location fingerprinting is a proteomic analysis technique capable of identifying structural modification-associated differences in mass spectrometry (MS) datasets of complex biological samples. A new webtool (Manchester Peptide Location Fingerprinter), applied to photoaged and intrinsically aged skin proteomes, can relatively quantify peptides (spectral counting) and map statistically significant differences to regions within protein structures. New photoageing biomarkers were identified in multiple proteins including matrix components (collagens and proteoglycans), oxidation and protease modulators (peroxiredoxins and SERPINs) and cytoskeletal proteins (keratins). Crucially, for many extracellular biomarkers, structural modification-associated differences were not correlated with relative abundance (by ion intensity). By applying peptide location fingerprinting to published MS datasets, (identifying biomarkers including collagen V and versican in ageing tendon) we demonstrate the potential of the MPLF webtool to discover novel biomarkers.

scholarly journals Mitochondrial DNA Variants and Common Diseases: A Mathematical Model for the Diversity of Age-Related mtDNA Mutations

Cells ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 608 ◽  
Author(s):  
Huanzheng Li ◽  
Jesse Slone ◽  
Lin Fei ◽  
Taosheng Huang
Keyword(s):  
Mutation Rate ◽  
Nuclear Dna ◽  
Eukaryotic Cell ◽  
Cellular Aging ◽  
Mtdna Mutation ◽  
Proliferating Cells ◽  
Mtdna Mutations ◽  
Common Diseases ◽  
Age Related ◽  
Primary Driver

The mitochondrion is the only organelle in the human cell, besides the nucleus, with its own DNA (mtDNA). Since the mitochondrion is critical to the energy metabolism of the eukaryotic cell, it should be unsurprising, then, that a primary driver of cellular aging and related diseases is mtDNA instability over the life of an individual. The mutation rate of mammalian mtDNA is significantly higher than the mutation rate observed for nuclear DNA, due to the poor fidelity of DNA polymerase and the ROS-saturated environment present within the mitochondrion. In this review, we will discuss the current literature showing that mitochondrial dysfunction can contribute to age-related common diseases such as cancer, diabetes, and other commonly occurring diseases. We will then turn our attention to the likely role that mtDNA mutation plays in aging and senescence. Finally, we will use this context to develop a mathematical formula for estimating for the accumulation of somatic mtDNA mutations with age. This resulting model shows that almost 90% of non-proliferating cells would be expected to have at least 100 mutations per cell by the age of 70, and almost no cells would have fewer than 10 mutations, suggesting that mtDNA mutations may contribute significantly to many adult onset diseases.

scholarly journals The Peptidyl-prolyl Isomerase Pin1 in Neuronal Signaling: from Neurodevelopment to Neurodegeneration

2020 ◽  
Author(s):  
Francesca Fagiani ◽  
Stefano Govoni ◽  
Marco Racchi ◽  
Cristina Lanni
Keyword(s):  
Intracellular Signaling ◽  
Cell Cycle Progression ◽  
Wide Spectrum ◽  
Relevant Information ◽  
Synaptic Activity ◽  
Biological Functions ◽  
Prolyl Isomerase ◽  
Proliferating Cells ◽  
Peptidyl Prolyl Isomerase ◽  
Age Related

Abstract The peptidyl-prolyl isomerase Pin1 is a unique enzyme catalyzing the isomerization of the peptide bond between phosphorylated serine-proline or threonine-proline motifs in proteins, thereby regulating a wide spectrum of protein functions, including folding, intracellular signaling, transcription, cell cycle progression, and apoptosis. Pin1 has been reported to act as a key molecular switch inducing cell-type-specific effects, critically depending on the different phosphorylation patterns of its targets within different biological contexts. While its implication in proliferating cells, and, in particular, in the field of cancer, has been widely characterized, less is known about Pin1 biological functions in terminally differentiated and post-mitotic neurons. Notably, Pin1 is widely expressed in the central and peripheral nervous system, where it regulates a variety of neuronal processes, including neuronal development, apoptosis, and synaptic activity. However, despite studies reporting the interaction of Pin1 with neuronal substrates or its involvement in specific signaling pathways, a more comprehensive understanding of its biological functions at neuronal level is still lacking. Besides its implication in physiological processes, a growing body of evidence suggests the crucial involvement of Pin1 in aging and age-related and neurodegenerative diseases, including Alzheimer’s disease, Parkinson disease, frontotemporal dementias, Huntington disease, and amyotrophic lateral sclerosis, where it mediates profoundly different effects, ranging from neuroprotective to neurotoxic. Therefore, a more detailed understanding of Pin1 neuronal functions may provide relevant information on the consequences of Pin1 deregulation in age-related and neurodegenerative disorders.

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