scholarly journals Enhanced Activity of Exportin-1/CRM1 in Neurons Contributes to Autophagy Dysfunction and Senescent Features in Old Mouse Brain

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
Elisa Gorostieta-Salas ◽  
Daniel Moreno-Blas ◽  
Cristian Gerónimo-Olvera ◽  
Bulmaro Cisneros ◽  
Felipe A. Court ◽  
...  
Keyword(s):  
Cellular Senescence ◽  
Brain Aging ◽  
Autophagic Flux ◽  
Proliferating Cells ◽  
Neuronal Homeostasis ◽  
Autophagic Degradation ◽  
Vitro Model ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome

Brain aging is characterized by dysfunctional autophagy and cellular senescence, among other features. While autophagy can either promote or suppress cellular senescence in proliferating cells, in postmitotic cells, such as neurons, autophagy impairment promotes cellular senescence. CRM1 (exportin-1/XPO1) exports hundreds of nuclear proteins into the cytoplasm, including the transcription factors TFEB (the main inducer of autophagy and lysosomal biogenesis genes) and STAT3, another autophagy modulator. It appears that CRM1 is a modulator of aging-associated senescence and autophagy, because pharmacological inhibition of CRM1 improved autophagic degradation in flies, by increasing nuclear TFEB levels, and because enhanced CRM1 activity is mechanistically linked to senescence in fibroblasts from Hutchinson–Gilford progeria syndrome patients and old healthy individuals; furthermore, the exogenous overexpression of CRM1 induced senescence in normal fibroblasts. In this work, we tested the hypothesis that impaired autophagic flux during brain aging occurs due to CRM1 accumulation in the brain. We found that CRM1 levels and activity increased in the hippocampus and cortex during physiological aging, which resulted in a decrease of nuclear TFEB and STAT3. Consistent with an autophagic flux impairment, we observed accumulation of the autophagic receptor p62/SQSTM1 in neurons of old mice, which correlated with increased neuronal senescence. Using an in vitro model of neuronal senescence, we demonstrate that CRM1 inhibition improved autophagy flux and reduced SA-β-gal activity by restoring TFEB nuclear localization. Collectively, our data suggest that enhanced CRM1-mediated export of proteins during brain aging perturbs neuronal homeostasis, contributing to autophagy impairment, and neuronal senescence.

scholarly journals The Cellular Senescence Stress Response in Post-Mitotic Brain Cells: Cell Survival at the Expense of Tissue Degeneration

Life ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 229
Author(s):  
Eric Sah ◽  
Sudarshan Krishnamurthy ◽  
Mohamed Y. Ahmidouch ◽  
Gregory J. Gillispie ◽  
Carol Milligan ◽  
...  
Keyword(s):  
Stress Response ◽  
Cell Fate ◽  
Cellular Senescence ◽  
Cell Biology ◽  
Brain Aging ◽  
Complex Stress ◽  
Brain Cell ◽  
Tissue Degeneration ◽  
Cellular Dna

In 1960, Rita Levi-Montalcini and Barbara Booker made an observation that transformed neuroscience: as neurons mature, they become apoptosis resistant. The following year Leonard Hayflick and Paul Moorhead described a stable replicative arrest of cells in vitro, termed “senescence”. For nearly 60 years, the cell biology fields of neuroscience and senescence ran in parallel, each separately defining phenotypes and uncovering molecular mediators to explain the 1960s observations of their founding mothers and fathers, respectively. During this time neuroscientists have consistently observed the remarkable ability of neurons to survive. Despite residing in environments of chronic inflammation and degeneration, as occurs in numerous neurodegenerative diseases, often times the neurons with highest levels of pathology resist death. Similarly, cellular senescence (hereon referred to simply as “senescence”) now is recognized as a complex stress response that culminates with a change in cell fate. Instead of reacting to cellular/DNA damage by proliferation or apoptosis, senescent cells survive in a stable cell cycle arrest. Senescent cells simultaneously contribute to chronic tissue degeneration by secreting deleterious molecules that negatively impact surrounding cells. These fields have finally collided. Neuroscientists have begun applying concepts of senescence to the brain, including post-mitotic cells. This initially presented conceptual challenges to senescence cell biologists. Nonetheless, efforts to understand senescence in the context of brain aging and neurodegenerative disease and injury emerged and are advancing the field. The present review uses pre-defined criteria to evaluate evidence for post-mitotic brain cell senescence. A closer interaction between neuro and senescent cell biologists has potential to advance both disciplines and explain fundamental questions that have plagued their fields for decades.

scholarly journals SPINK1-induced amelioration of impaired autophagy contributes to suppression of trypsinogen activation in a model of acute pancreatitis

2020 ◽  
Author(s):  
Yuxiao Zhao ◽  
Jianlong Jia ◽  
Abdullah Shopit ◽  
Yang Liu ◽  
Jun Wang
Keyword(s):  
Acute Pancreatitis ◽  
In Vitro Model ◽  
Autophagic Flux ◽  
Trypsin Activity ◽  
Autophagy Flux ◽  
Trypsinogen Activation ◽  
Vitro Model ◽  
First Time ◽  
Induced Amelioration

AbstractSPINK1 has been regarded as a reversible trypsinogen inhibitor for the inappropriate activation of trypsin, a key step in the initiation of acute pancreatitis (AP). However, the mechanisms of its action remains largely unclear and controversial. Here, we reported an unexpected effects of SPINK1 on inhibiting trypsinogen activation through the regulation of impaired autophagy in cerulein-stimulated AR42J cells, a well-established in vitro model of acute pancreatitis. Firstly, we found that the impaired autophagic flux was induced and trypsinogen activity enhanced in the above setting. Then, we showed that SPINK1 overexpression could inhibit the level of increased autophagic activity, improving the hindered autophagy flux, and significantly decreased the trypsinogen activity, whereas shRNA-caused downregulation of SPINK1 exacerbated the impairment of autophagic flux and trypsin activity, in the same cerulein-processed cells. More importantly, the trypsinogen activation in this model could be ameliorated by 3-Methyladenine(3-MA), an autophagy inhibitor. Thus, this study revealed, possibly for the first time, that SPINK1 greatly blocked the trypsinogen activation possibly through the modulation of impaired autophagy in cerulein-induced in vitro model of acute pancreatitis.

Features of the in vitro expression profile of hippocampal neurogenic niche cells during optogenetic stimulation

2021 ◽  
Vol 67 (1) ◽  
pp. 34-41
Author(s):  
E.D. Khilazheva ◽  
A.V. Morgun ◽  
E.B. Boytsova ◽  
A.I. Mosiagina ◽  
A.N. Shuvaev ◽  
...  
Keyword(s):  
Stem Cells ◽  
Expression Profile ◽  
In Vitro Model ◽  
Postnatal Period ◽  
Proliferating Cells ◽  
Aberrant Expression ◽  
Intercellular Interactions ◽  
Neurogenic Niche ◽  
Vitro Model

In the central nervous system of mammals, there are specialized areas in which neurogenesis — neurogenic niches — is observed in the postnatal period. It is believed that astrocytes in the composition of neurogenic niches play a significant role in the regulation of neurogenesis, and therefore they are considered as a promising “target” for the possible control of neurogenesis, including the use of optogenetics. In the framework of this work, we formed an in vitro model of a neurogenic niche, consisting of cerebral endothelial cells, astrocytes and neurospheres. Astrocytes in the neurogenic niche model expressed canalorodopsin ChR2 and underwent photoactivation. The effect of photoactivated astrocytes on the expression profile of neurogenic niche cells was evaluated using immunocytochemical analysis methods. It was found that intact astrocytes in the composition of the neurogenic niche contribute to neuronal differentiation of stem cells, as well as the activation of astroglia expressing photosensitive proteins, changes the expression of molecules characterized by intercellular interactions of pools of resting and proliferating cells in the composition of the neurogenic niche with the participation of NAD+ (Cx43, CD38, CD157), lactate (MCT1). In particular, the registered changes reflect a violation of the paracrine intercellular interactions of two subpopulations of cells, one of which acts as a source of NAD+, and the second as a consumer of NAD+ to ensure the processes of intracellular signal transduction; a change in the mechanisms of lactate transport due to aberrant expression of the lactate transporter MCT1 in cells forming a pool of cells developing along the neuronal path of differentiation. In general, with photostimulation of niche astrocytes, the total proliferative activity increases mainly due to neural progenitor cells, but not neural stem cells. Thus, optogenetic activation of astrocytes can become a promising tool for controlling the activity of neurogenesis processes and the formation of a local proneurogenic microenvironment in an in vitro model of a neurogenic niche.

A genome-wide CRISPR-based screen identifies KAT7 as a driver of cellular senescence

2021 ◽  
Vol 13 (575) ◽  
pp. eabd2655
Author(s):  
Wei Wang ◽  
Yuxuan Zheng ◽  
Shuhui Sun ◽  
Wei Li ◽  
Moshi Song ◽  
...  
Keyword(s):  
Cellular Senescence ◽  
Werner Syndrome ◽  
Embryonic Stem ◽  
Accelerated Aging ◽  
Premature Aging ◽  
Mesenchymal Precursor Cells ◽  
Genome Wide ◽  
A Genome ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome

Understanding the genetic and epigenetic bases of cellular senescence is instrumental in developing interventions to slow aging. We performed genome-wide CRISPR-Cas9–based screens using two types of human mesenchymal precursor cells (hMPCs) exhibiting accelerated senescence. The hMPCs were derived from human embryonic stem cells carrying the pathogenic mutations that cause the accelerated aging diseases Werner syndrome and Hutchinson-Gilford progeria syndrome. Genes whose deficiency alleviated cellular senescence were identified, including KAT7, a histone acetyltransferase, which ranked as a top hit in both progeroid hMPC models. Inactivation of KAT7 decreased histone H3 lysine 14 acetylation, repressed p15INK4b transcription, and alleviated hMPC senescence. Moreover, lentiviral vectors encoding Cas9/sg-Kat7, given intravenously, alleviated hepatocyte senescence and liver aging and extended life span in physiologically aged mice as well as progeroid Zmpste24−/− mice that exhibit a premature aging phenotype. CRISPR-Cas9–based genetic screening is a robust method for systematically uncovering senescence genes such as KAT7, which may represent a therapeutic target for developing aging interventions.

scholarly journals Neurogenesis and brain aging

2019 ◽  
Vol 30 (6) ◽  
pp. 573-580 ◽  
Author(s):  
Nickolay K. Isaev ◽  
Elena V. Stelmashook ◽  
Elisaveta E. Genrikhs
Keyword(s):  
Brain Aging ◽  
Werner Syndrome ◽  
Accelerated Aging ◽  
Normal Aging ◽  
Postnatal Period ◽  
Human Aging ◽  
Distinctive Features ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome ◽  
The Brain

AbstractHuman aging affects the entire organism, but aging of the brain must undoubtedly be different from that of all other organs, as neurons are highly differentiated postmitotic cells, for the majority of which the lifespan in the postnatal period is equal to the lifespan of the entire organism. In this work, we examine the distinctive features of brain aging and neurogenesis during normal aging, pathological aging (Alzheimer’s disease), and accelerated aging (Hutchinson-Gilford progeria syndrome and Werner syndrome).

scholarly journals Neuropeptide Y Enhances Progerin Clearance and Ameliorates the Senescent Phenotype of Human Hutchinson-Gilford Progeria Syndrome Cells

2020 ◽  
Vol 75 (6) ◽  
pp. 1073-1078 ◽  
Author(s):  
Célia A Aveleira ◽  
Marisa Ferreira-Marques ◽  
Luísa Cortes ◽  
Jorge Valero ◽  
Dina Pereira ◽  
...  
Keyword(s):  
Neuropeptide Y ◽  
Caloric Restriction ◽  
Cellular Senescence ◽  
Dermal Fibroblasts ◽  
Cellular Aging ◽  
Premature Aging ◽  
Whole Body ◽  
Lamin A ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome

Abstract Hutchinson-Gilford progeria syndrome (HGPS, or classical progeria) is a rare genetic disorder, characterized by premature aging, and caused by a de novo point mutation (C608G) within the lamin A/C gene (LMNA), producing an abnormal lamin A protein, termed progerin. Accumulation of progerin causes nuclear abnormalities and cell cycle arrest ultimately leading to cellular senescence. Autophagy impairment is a hallmark of cellular aging, and the rescue of this proteostasis mechanism delays aging progression in HGPS cells. We have previously shown that the endogenous Neuropeptide Y (NPY) increases autophagy in hypothalamus, a brain area already identified as a central regulator of whole-body aging. We also showed that NPY mediates caloric restriction-induced autophagy. These results are in accordance with other studies suggesting that NPY may act as a caloric restriction mimetic and plays a role as a lifespan and aging regulator. The aim of the present study was, therefore, to investigate if NPY could delay HGPS premature aging phenotype. Herein, we report that NPY increases autophagic flux and progerin clearance in primary cultures of human dermal fibroblasts from HGPS patients. NPY also rescues nuclear morphology and decreases the number of dysmorphic nuclei, a hallmark of HGPS cells. In addition, NPY decreases other hallmarks of aging as DNA damage and cellular senescence. Altogether, these results show that NPY rescues several hallmarks of cellular aging in HGPS cells, suggesting that NPY can be considered a promising strategy to delay or block the premature aging of HGPS.

Emerging candidate treatment strategies for Hutchinson-Gilford progeria syndrome

2017 ◽  
Vol 45 (6) ◽  
pp. 1279-1293 ◽  
Author(s):  
Charlotte Strandgren ◽  
Gwladys Revêchon ◽  
Agustín Sola Carvajal ◽  
Maria Eriksson
Keyword(s):  
De Novo ◽  
Disease Incidence ◽  
Treatment Strategies ◽  
Premature Aging ◽  
Lamin A ◽  
Lmna Gene ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome

Hutchinson-Gilford progeria syndrome (HGPS, progeria) is an extremely rare premature aging disorder affecting children, with a disease incidence of ∼1 in 18 million individuals. HGPS is usually caused by a de novo point mutation in exon 11 of the LMNA gene (c.1824C>T, p.G608G), resulting in the increased usage of a cryptic splice site and production of a truncated unprocessed lamin A protein named progerin. Since the genetic cause for HGPS was published in 2003, numerous potential treatment options have rapidly emerged. Strategies to interfere with the post-translational processing of lamin A, to enhance progerin clearance, or directly target the HGPS mutation to reduce the progerin-producing alternative splicing of the LMNA gene have been developed. Here, we give an up-to-date resume of the contributions made by our and other research groups to the growing list of different candidate treatment strategies that have been tested, both in vitro, in vivo in mouse models for HGPS and in clinical trials in HGPS patients.

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