Differentiation and De-Differentiation—Neuronal Cell-Cycle Regulation During Development and Age-Related Neurodegenerative Disorders

Author(s):  
T. Arendt
Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Umadevi V Wesley ◽  
Daniel Tremmel ◽  
Robert Dempsey

Introduction: The molecular mechanisms of cerebral ischemia damage and protection are not completely understood, but a number of reports implicate the contribution of lipid metabolism and cell-cycle regulating proteins in stroke out come. We have previously shown that tricyclodecan-9-yl-xanthogenate (D609) resulted in increased ceramide levels after transient middle cerebral artery occlusion (tMCAO) in spontaneously hypertensive rat (SHR). We hypothesized that D609 induced cell cycle arrest probably by inhibiting sphingomyelin synthase (SMS). In this study, we examined the direct effects of SMS on cell cycle progression and proliferation of neuroblast cells. Methods: Ischemia was induced by middle cerebral artery occlusion (MCAO) and reperfusion. Expression levels were measured by western blot analysis, RT-PCR, and Immunofluorescence staining. SMS1 and 2 expressions were silenced by stable transfection with SMS1/2-targeted shRNA. Cell cycle analysis was performed using Flow cytometry. Data were analyzed using MODFIT cell cycle analysis program. Cell proliferation rate was measured by MTT assay. Results: We have identified that the expression of SMS1is significantly up-regulated in the ischemic hemisphere following MCAO. Neuro-2a cells transfected with SMS specific ShRNA acquired more neuronal like phenotype and exhibited decreased proliferation rate. Also, silencing of both SMS1 and 2 induced cell-cycle arrest as shown by significantly increased percentage of cells in G0/G1 and decreased proportion of cells in S-phase as compared to control cells. This was accompanied by up-regulation of cyclin-dependent kinase (Cdk) inhibitors p21 and decreased levels of phophorylated AKT levels. Furthermore, loss of SMS inhibited the migratory potential of Neuro 2a cells. Summary: Up-regulation of SMS under ischemic/reperfusion conditions suggests that this enzyme potentially contributes to cell cycle regulation and may contribute to maintaining neuronal cell population. Further studies may open up a new direction for identifying the molecular mechanisms of cell cycle regulation and protection following ischemic stroke


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Mathieu Daynac ◽  
Lise Morizur ◽  
Alexandra Chicheportiche ◽  
Marc-André Mouthon ◽  
François D. Boussin

10.2741/a501 ◽  
2000 ◽  
Vol 5 (3) ◽  
pp. d121-137 ◽  
Author(s):  
John W Ludlow

2019 ◽  
Vol 21 (10) ◽  
pp. 1297-1309 ◽  
Author(s):  
Denise D Correa ◽  
Jaya Satagopan ◽  
Axel Martin ◽  
Erica Braun ◽  
Maria Kryza-Lacombe ◽  
...  

AbstractBackgroundPatients with brain tumors treated with radiotherapy (RT) and chemotherapy (CT) often experience cognitive dysfunction. We reported that single nucleotide polymorphisms (SNPs) in the APOE, COMT, and BDNF genes may influence cognition in brain tumor patients. In this study, we assessed whether genes associated with late-onset Alzheimer’s disease (LOAD), inflammation, cholesterol transport, dopamine and myelin regulation, and DNA repair may influence cognitive outcome in this population.MethodsOne hundred and fifty brain tumor patients treated with RT ± CT or CT alone completed a neurocognitive assessment and provided a blood sample for genotyping. We genotyped genes/SNPs in these pathways: (i) LOAD risk/inflammation/cholesterol transport, (ii) dopamine regulation, (iii) myelin regulation, (iv) DNA repair, (v) blood–brain barrier disruption, (vi) cell cycle regulation, and (vii) response to oxidative stress. White matter (WM) abnormalities were rated on brain MRIs.ResultsMultivariable linear regression analysis with Bayesian shrinkage estimation of SNP effects, adjusting for relevant demographic, disease, and treatment variables, indicated strong associations (posterior association summary [PAS] ≥ 0.95) among tests of attention, executive functions, and memory and 33 SNPs in genes involved in: LOAD/inflammation/cholesterol transport (eg, PDE7A, IL-6), dopamine regulation (eg, DRD1, COMT), myelin repair (eg, TCF4), DNA repair (eg, RAD51), cell cycle regulation (eg, SESN1), and response to oxidative stress (eg, GSTP1). The SNPs were not significantly associated with WM abnormalities.ConclusionThis novel study suggests that polymorphisms in genes involved in aging and inflammation, dopamine, myelin and cell cycle regulation, and DNA repair and response to oxidative stress may be associated with cognitive outcome in patients with brain tumors.


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