scholarly journals Cell Cycle Re-entry in the Nervous System: From Polyploidy to Neurodegeneration

2021 ◽  
Vol 9 ◽  
Author(s):  
Shyama Nandakumar ◽  
Emily Rozich ◽  
Laura Buttitta
Keyword(s):  
Cell Cycle ◽  
Nervous System ◽  
Cell Damage ◽  
Neuronal Cell ◽  
Cell Loss ◽  
Protective Role ◽  
Cellular Growth ◽  
Model Organisms ◽  
Differentiated Cells ◽  
Cell Cycle Reentry

Terminally differentiated cells of the nervous system have long been considered to be in a stable non-cycling state and are often considered to be permanently in G0. Exit from the cell cycle during development is often coincident with the differentiation of neurons, and is critical for neuronal function. But what happens in long lived postmitotic tissues that accumulate cell damage or suffer cell loss during aging? In other contexts, cells that are normally non-dividing or postmitotic can or re-enter the cell cycle and begin replicating their DNA to facilitate cellular growth in response to cell loss. This leads to a state called polyploidy, where cells contain multiple copies of the genome. A growing body of literature from several vertebrate and invertebrate model organisms has shown that polyploidy in the nervous system may be more common than previously appreciated and occurs under normal physiological conditions. Moreover, it has been found that neuronal polyploidization can play a protective role when cells are challenged with DNA damage or oxidative stress. By contrast, work over the last two and a half decades has discovered a link between cell-cycle reentry in neurons and several neurodegenerative conditions. In this context, neuronal cell cycle re-entry is widely considered to be aberrant and deleterious to neuronal health. In this review, we highlight historical and emerging reports of polyploidy in the nervous systems of various vertebrate and invertebrate organisms. We discuss the potential functions of polyploidization in the nervous system, particularly in the context of long-lived cells and age-associated polyploidization. Finally, we attempt to reconcile the seemingly disparate associations of neuronal polyploidy with both neurodegeneration and neuroprotection.

Abstract 2357: Src Kinase Inhibition Blocks Thrombin-induced Brain Injuries without Cognitive Side Effects

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Da-Zhi Liu ◽  
Bradley P Ander ◽  
Ali Izadi ◽  
Ken Van ◽  
Xinhua Zhan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cognitive Deficits ◽  
Neuronal Cell ◽  
Thrombin Injection ◽  
Cell Cycle Reentry ◽  
Cell Cycle Inhibition ◽  
Mature Neurons ◽  
Cognitive Side Effects

Intracerebral hemorrhage (ICH) activates thrombin, a potent mitogen. Thrombin triggers mitosis by modulating several intracellular mitogenic molecules including Src family kinases. These molecules regulate mitogen-activated protein kinases (MAPKs) and cell cycle proteins such as cyclin-dependent kinases (Cdks); and play critical roles in mitogenic signaling pathways and cell cycle progression. Since aberrant cell cycle reentry results in death of mature neurons, cell cycle inhibition appears to be a candidate strategy for the treatment of neurological diseases including ICH. However, this can also block cell cycle (proliferation) of neural progenitor cells (NPCs) and thus impair brain neurogenesis leading to cognitive deficits. We hypothesized that inhibition of cell cycle by blocking mitogenic signaling molecules (i.e., Src family kinase members) blocks cell cycle reentry of mature neurons without injuring NPCs, which will avoid cognitive side effects during cell cycle inhibition treatment for ICH. Our data shows: (1) Thrombin 30U/ml results in apoptosis of mature neurons via neuronal cell cycle reentry in vitro ; (2) PP2 (Src family kinase inhibitor) 0.3 µM attenuates the thrombin-induced neuronal apoptosis via blocking neuronal cell cycle reentry, but does not affect the viability of NPCs at the same doses in vitro ; (3) Intracerebral ventricular thrombin injection (20U, i.c.v.) results in neuron loss in hippocampus and cognitive deficits 5 weeks after thrombin injection in vivo ; (4) PP2 (1mg/kg, i.p.), given immediately after thrombin injection (i.c.v.), blocks the thrombin-induced neuron loss in hippocampus and cognitive deficits, whereas PP2 on its own at the same doses does not affect normal cognition in vivo . These suggest that Src kinase inhibition prevents hippocampal neuron death via blocking neuronal cell cycle reentry after ICH, but does not affect survival of NPCs.

scholarly journals Distinct Developmental Roles of Cell Cycle Inhibitors p57Kip2 and p27Kip1 Distinguish Pituitary Progenitor Cell Cycle Exit from Cell Cycle Reentry of Differentiated Cells

2009 ◽  
Vol 29 (7) ◽  
pp. 1895-1908 ◽  
Author(s):  
Steve Bilodeau ◽  
Audrey Roussel-Gervais ◽  
Jacques Drouin
Keyword(s):  
Cell Cycle ◽  
Progenitor Cell ◽  
Cell Cycle Exit ◽  
Loss Of Function ◽  
Temporal Separation ◽  
Developmental Program ◽  
Differentiated Cells ◽  
Cell Cycle Reentry ◽  
Dependent Cell ◽  
Cell Cycle Inhibitors

ABSTRACT Patterning and differentiation signals are often believed to drive the developmental program, including cell cycle exit of proliferating progenitors. Taking advantage of the spatial and temporal separation of proliferating and differentiated cells within the developing anterior pituitary gland, we investigated the control of cell proliferation during organogenesis. Thus, we identified a population of noncycling precursors that are uniquely marked by expression of the cell cycle inhibitor p57Kip2 and by cyclin E. In p57Kip2−/− mice, the developing pituitary is hyperplastic due to accumulation of proliferating progenitors, whereas overexpression of p57Kip2 leads to hypoplasia. p57Kip2-dependent cell cycle exit is not required for differentiation, and conversely, blockade of cell differentiation, as achieved in Tpit−/− pituitaries, does not prevent cell cycle exit but rather leads to accumulation of p57Kip2-positive precursors. Upon differentiation, p57Kip2 is replaced by p27Kip1. Accordingly, proliferating differentiated cells are readily detected in p27Kip1−/− pituitaries but not in wild-type or p57Kip2−/− pituitaries. Strikingly, all cells of p57Kip2−/−;p27Kip1−/− pituitaries are proliferative. Thus, during normal development, progenitor cell cycle exit is controlled by p57Kip2 followed by p27Kip1 in differentiated cells; these sequential actions, taken together with different pituitary outcomes of their loss of function, suggest hierarchical controls of the cell cycle that are independent of differentiation.

scholarly journals Testing the Neuroprotective Properties of PCSO-524® Using a Neuronal Cell Cycle Suppression Assay

Marine Drugs ◽  
2019 ◽  
Vol 17 (2) ◽  
pp. 79 ◽  
Author(s):  
Beika Zhu ◽  
Yang Zhang ◽  
Karl Herrup
Keyword(s):  
Cell Cycle ◽  
Neurodegenerative Disease ◽  
Neuronal Cell ◽  
Brain Inflammation ◽  
Neuroprotective Effects ◽  
Ht22 Cells ◽  
Cell Cycle Reentry ◽  
The Central Nervous System ◽  
Vitro Model

Cell cycle reentry is a unified mechanism shared by several neurodegenerative diseases, including Alzheimer’s disease (AD) and Ataxia Telangiectasia (A-T). This phenotype is often related to neuroinflammation in the central nervous system. To mimic brain inflammation in vitro, we adopted the previously established method of using conditioned medium collected from activated THP-1 cells and applied it to both differentiated HT22 cells and primary neurons. Unscheduled cell cycle events were observed in both systems, indicating the potential of this approach as an in vitro model of neurodegenerative disease. We used this assay to measure the neuroprotective effects of New Zealand green-lipped mussel extract, PCSO-524®, to protect post-mitotic cells from cell cycle reentry. We found that, both in vitro and in an animal model, PCSO-524® displayed promising neuroprotective effects, and thus has potential to postpone or prevent the onset of neurodegenerative disease.

scholarly journals Adult enteric nervous system in health is maintained by a dynamic balance between neuronal apoptosis and neurogenesis

2017 ◽  
Vol 114 (18) ◽  
pp. E3709-E3718 ◽  
Author(s):  
Subhash Kulkarni ◽  
Maria-Adelaide Micci ◽  
Jenna Leser ◽  
Changsik Shin ◽  
Shiue-Cheng Tang ◽  
...  
Keyword(s):  
Nervous System ◽  
Enteric Nervous System ◽  
Dynamic Balance ◽  
Neuronal Cell ◽  
Cell Loss ◽  
Enteric Neurons ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog ◽  
Myenteric Ganglia

According to current dogma, there is little or no ongoing neurogenesis in the fully developed adult enteric nervous system. This lack of neurogenesis leaves unanswered the question of how enteric neuronal populations are maintained in adult guts, given previous reports of ongoing neuronal death. Here, we confirm that despite ongoing neuronal cell loss because of apoptosis in the myenteric ganglia of the adult small intestine, total myenteric neuronal numbers remain constant. This observed neuronal homeostasis is maintained by new neurons formed in vivo from dividing precursor cells that are located within myenteric ganglia and express both Nestin and p75NTR, but not the pan-glial marker Sox10. Mutation of the phosphatase and tensin homolog gene in this pool of adult precursors leads to an increase in enteric neuronal number, resulting in ganglioneuromatosis, modeling the corresponding disorder in humans. Taken together, our results show significant turnover and neurogenesis of adult enteric neurons and provide a paradigm for understanding the enteric nervous system in health and disease.

scholarly journals Interplay between MEK-ERK signaling, cyclin D1, and cyclin-dependent kinase 5 regulates cell cycle reentry and apoptosis of neurons

2012 ◽  
Vol 23 (18) ◽  
pp. 3722-3730 ◽  
Author(s):  
Prashant Kumar Modi ◽  
Narayana Komaravelli ◽  
Neha Singh ◽  
Pushkar Sharma
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Molecular Mechanisms ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Amyloid Peptide ◽  
Erk Signaling ◽  
Cyclin Dependent Kinase ◽  
Cell Cycle Reentry ◽  
Cyclin Dependent Kinase 5

In response to neurotoxic signals, postmitotic neurons make attempts to reenter the cell cycle, which results in their death. Although several cell cycle proteins have been implicated in cell cycle–related neuronal apoptosis (CRNA), the molecular mechanisms that underlie this important event are poorly understood. Here, we demonstrate that neurotoxic agents such as β-amyloid peptide cause aberrant activation of mitogen-activated kinase kinase (MEK)–extracellular signal-regulated kinase (ERK) signaling, which promotes the entry of neurons into the cell cycle, resulting in their apoptosis. The MEK-ERK pathway regulates CRNA by elevating the levels of cyclin D1. The increase in cyclin D1 attenuates the activation of cyclin-dependent kinase 5 (cdk5) by its neuronal activator p35. The inhibition of p35-cdk5 activity results in enhanced MEK-ERK signaling, leading to CRNA. These studies highlight how neurotoxic signals reprogram and alter the neuronal signaling machinery to promote their entry into the cell cycle, which eventually leads to neuronal cell death.

scholarly journals Cell Cycle Inhibition without Disruption of Neurogenesis Is a Strategy for Treatment of Aberrant Cell Cycle Diseases: An Update

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Da-Zhi Liu ◽  
Bradley P. Ander
Keyword(s):  
Cell Cycle ◽  
Central Nervous System ◽  
Nervous System ◽  
Cognitive Deficits ◽  
Neural Progenitor Cells ◽  
Common Mechanism ◽  
Cns Diseases ◽  
Aberrant Cell ◽  
Cell Cycle Reentry ◽  
Cell Cycle Inhibition

Since publishing our earlier report describing a strategy for the treatment of central nervous system (CNS) diseases by inhibiting the cell cycle and without disrupting neurogenesis (Liu et al. 2010), we now update and extend this strategy to applications in the treatment of cancers as well. Here, we put forth the concept of “aberrant cell cycle diseases” to include both cancer and CNS diseases, the two unrelated disease types on the surface, by focusing on a common mechanism in each aberrant cell cycle reentry. In this paper, we also summarize the pharmacological approaches that interfere with classical cell cycle molecules and mitogenic pathways to block the cell cycle of tumor cells (in treatment of cancer) as well as to block the cell cycle of neurons (in treatment of CNS diseases). Since cell cycle inhibition can also block proliferation of neural progenitor cells (NPCs) and thus impair brain neurogenesis leading to cognitive deficits, we propose that future strategies aimed at cell cycle inhibition in treatment of aberrant cell cycle diseases (i.e., cancers or CNS diseases) should be designed with consideration of the important side effects on normal neurogenesis and cognition.

scholarly journals The effect of ATM knockdown on ionizing radiation-induced neuronal cell cycle reentry in Drosophila

Cell Cycle ◽  
2010 ◽  
Vol 9 (13) ◽  
pp. 2686-2687
Author(s):  
Stacey A. Rimkus ◽  
Andrew J. Petersen ◽  
Rebeccah J. Katzenberger ◽  
David A. Wassarman
Keyword(s):  
Cell Cycle ◽  
Ionizing Radiation ◽  
Neuronal Cell ◽  
Cell Cycle Reentry ◽  
Radiation Induced

scholarly journals Regulator of Cell Cycle (RGCC) Expression during the Progression of Alzheimer's Disease

2017 ◽  
Vol 26 (4) ◽  
pp. 693-702 ◽  
Author(s):  
Scott E. Counts ◽  
Elliott J. Mufson
Keyword(s):  
Alzheimer’S Disease ◽  
Cell Cycle ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Neuronal Cell ◽  
Cyclin B1 ◽  
Multifunctional Protein ◽  
Protein Levels ◽  
Cell Cycle Reentry ◽  
M Phase

Unscheduled cell cycle reentry of postmitotic neurons has been described in cases of mild cognitive impairment (MCI) and Alzheimer's disease (AD) and may form a basis for selective neuronal vulnerability during disease progression. In this regard, the multifunctional protein regulator of cell cycle (RGCC) has been implicated in driving G1/S and G2/M phase transitions through its interactions with cdc/cyclin-dependent kinase 1 (cdk1) and is induced by p53, which mediates apoptosis in neurons. We tested whether RGCC levels were dysregulated in frontal cortex samples obtained postmortem from subjects who died with a clinical diagnosis of no cognitive impairment (NCI), MCI, or AD. RGCC mRNA and protein levels were upregulated by ~50%-60% in MCI and AD compared to NCI, and RGCC protein levels were associated with poorer antemortem global cognitive performance in the subjects examined. To test whether RGCC might regulate neuronal cell cycle reentry and apoptosis, we differentiated neuronotypic PC12 cultures with nerve growth factor (NGF) followed by NGF withdrawal to induce abortive cell cycle activation and cell death. Experimental reduction of RGCC levels increased cell survival and reduced levels of the cdk1 target cyclin B1. RGCC may be a candidate cell cycle target for neuroprotection during the onset of AD.

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