Role of the transcription factor E2F1 in CXCR4-mediated neurotoxicity and HIV neuropathology

Shimizu, Saori; Khan, Muhammad Zafrullah; Hippensteel, Randi; Parkar, Anjum; Raghupathi, Ramesh; Meucci, Olimpia

doi:10.1016/j.nbd.2006.08.004

Cited by 29 publications

(37 citation statements)

References 43 publications

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“…The chemokine CXCL12 and its cognate receptor CXCR4 perform multiple functions essential for CNS development and function, including guiding migration and differentiation of neuronal precursor cells (1), regulating cell cycle proteins (2)(3)(4), and modulating NMDA receptor signaling (5). These homeostatic functions take on added significance within the context of neuroinflammatory disease, as the CXCL12/CXCR4 signaling axis aids recovery by promoting survival of mature neurons, recruitment of neural and glial progenitor cells (6)(7)(8), and neuronal-glial communication (9).…”

Section: Introductionmentioning

confidence: 99%

Neuronal ferritin heavy chain and drug abuse affect HIV-associated cognitive dysfunction

Pitcher¹,

Abt²,

Myers³

et al. 2014

J. Clin. Invest.

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Interaction of the chemokine CXCL12 with its receptor CXCR4 promotes neuronal function and survival during embryonic development and throughout adulthood. Previous studies indicated that μ-opioid agonists specifically elevate neuronal levels of the protein ferritin heavy chain (FHC), which negatively regulates CXCR4 signaling and affects the neuroprotective function of the CXCL12/CXCR4 axis. Here, we determined that CXCL12/CXCR4 activity increased dendritic spine density, and also examined FHC expression and CXCR4 status in opiate abusers and patients with HIV-associated neurocognitive disorders (HAND), which is typically exacerbated by illicit drug use. Drug abusers and HIV patients with HAND had increased levels of FHC, which correlated with reduced CXCR4 activation, within cortical neurons. We confirmed these findings in a nonhuman primate model of SIV infection with morphine administration. Transfection of a CXCR4-expressing human cell line with an iron-deficient FHC mutant confirmed that increased FHC expression deregulated CXCR4 signaling and that this function of FHC was independent of iron binding. Furthermore, examination of morphine-treated rodents and isolated neurons expressing FHC shRNA revealed that FHC contributed to morphine-induced dendritic spine loss. Together, these data implicate FHC-dependent deregulation of CXCL12/CXCR4 as a contributing factor to cognitive dysfunction in neuroAIDS.

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Section: Introductionmentioning

confidence: 99%

Neuronal ferritin heavy chain and drug abuse affect HIV-associated cognitive dysfunction

Pitcher¹,

Abt²,

Myers³

et al. 2014

J. Clin. Invest.

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“…Neurons can be easily separated from the glial layer at any time during culture and used for different experimental applications ranging from electrophysiology 4 , cellular and molecular biology 5-8 , biochemistry 5 , imaging and microscopy 4,6,7,9,10 . The primary neurons extend axons and dendrites to form functional synapses 11 , a process which is not observed in neuronal cell lines, although some cell lines do extend processes.…”

Section: Introductionmentioning

confidence: 99%

Bilaminar Co-culture of Primary Rat Cortical Neurons and Glia

Shimizu

Abt

Meucci

2011

JoVE

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This video will guide you through the process of culturing rat cortical neurons in the presence of a glial feeder layer, a system known as a bilaminar or co-culture model. This system is suitable for a variety of experimental needs requiring either a glass or plastic growth substrate and can also be used for culture of other types of neurons.Rat cortical neurons obtained from the late embryonic stage (E17) are plated on glass coverslips or tissue culture dishes facing a feeder layer of glia grown on dishes or plastic coverslips (known as Thermanox), respectively. The choice between the two configurations depends on the specific experimental technique used, which may require, or not, that neurons are grown on glass (e.g. calcium imaging versus Western blot). The glial feeder layer, an astroglia-enriched secondary culture of mixed glia, is separately prepared from the cortices of newborn rat pups (P2-4) prior to the neuronal dissection.A major advantage of this culture system as compared to a culture of neurons only is the support of neuronal growth, survival, and differentiation provided by trophic factors secreted from the glial feeder layer, which more accurately resembles the brain environment in vivo. Furthermore, the co-culture can be used to study neuronal-glial interactions 1 .At the same time, glia contamination in the neuronal layer is prevented by different means (low density culture, addition of mitotic inhibitors, lack of serum and use of optimized culture medium) leading to a virtually pure neuronal layer, comparable to other established methods [1][2][3] . Neurons can be easily separated from the glial layer at any time during culture and used for different experimental applications ranging from electrophysiology 4 , cellular and molecular biology 5-8 , biochemistry 5 , imaging and microscopy 4,6,7,9,10 . The primary neurons extend axons and dendrites to form functional synapses 11 , a process which is not observed in neuronal cell lines, although some cell lines do extend processes.A detailed protocol of culturing rat hippocampal neurons using this co-culture system has been described previously 4,12,13 . Here we detail a modified protocol suited for cortical neurons. As approximately 20x10 6 cells are recovered from each rat embryo, this method is particularly useful for experiments requiring large numbers of neurons (but not concerned about a highly homogenous neuronal population). The preparation of neurons and glia needs to be planned in a time-specific manner. We will provide the step-by-step protocol for culturing rat cortical neurons as well as culturing glial cells to support the neurons.

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“…5,13,14 Our previous studies show that CXCL12 rescues neurons exposed to proapoptotic insults that cause Rb phosphorylation and its subsequent deficit (including HIV-1 gp120). 4,5 These data raise the possibility that Rb may act downstream of CXCR4 and suggest that CXCL12 promotes neuronal survival and differentiation by supporting Rb function. To test these hypotheses, the mechanisms involved in control of neuronal Rb by CXCL12 and the role of Rb in the neuroprotective action of the chemokine were investigated.…”

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confidence: 98%

“…11 Alterations of Rb/E2F pathway were reported in various neuropathologies, such as Parkinson's and Alzheimer's diseases and HIV encephalitis. 5,13,14 Our previous studies show that CXCL12 rescues neurons exposed to proapoptotic insults that cause Rb phosphorylation and its subsequent deficit (including HIV-1 gp120). 4,5 These data raise the possibility that Rb may act downstream of CXCR4 and suggest that CXCL12 promotes neuronal survival and differentiation by supporting Rb function.…”

mentioning

confidence: 98%

“…1,3 For instance, CXCR4 stimulates the PI3K/Akt pathway and regulates cell-cycle proteins in neurons. [3][4][5][6] Under pathological conditions at least some of these essential CXCR4 functions are compromised, leading to neuronal dysfunction/death. 1,7 Thus, a complete understanding of the effects of CXCR4 activation in the brain has important physiological and pathological implications.…”

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confidence: 99%

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The chemokine CXCL12 promotes survival of postmitotic neurons by regulating Rb protein

et al. 2008

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Postmitotic neurons need to keep their cell cycle under control to survive and maintain a differentiated state. This study aims to test the hypothesis that the chemokine CXCL12 regulates neuronal survival and differentiation by promoting Rb function, as suggested by previous studies showing that CXCL12 protects neurons from apoptosis induced by Rb loss. To this end, the effect of CXCL12 on Rb expression and transcriptional activity and the role of Rb in CXCL12-induced neuronal survival were studied. CXCL12 increases Rb protein and RNA levels in rat cortical neurons. The chemokine also stimulates an exogenous Rb promoter expressed in these neurons and counteracts the inhibition of the Rb promoter induced by E2F1 overexpression. Furthermore CXCL12 stimulates Rb activity as a transcription repressor. The effects of CXCL12 are mediated by its specific receptor CXCR4, and do not require the presence of glia. Finally, shRNA studies show that Rb expression is crucial to the neuroprotective activity of CXCL12 as indicated by NMDA-neurotoxicity assays. These findings suggest that proper CXCR4 stimulation in the mature CNS can prevent impairment of the Rb-E2F pathway and support neuronal survival. This is important to maintain CNS integrity in physiological conditions and prevent neuronal injury and loss typical of many neurodegenerative and neuroinflammatory conditions. Cell Death and Differentiation ( 1,2 Stimulation of CXCR4 by its endogenous ligand leads to activation of intracellular pathways affecting neuronal survival, migration, and neurotransmission.1,3 For instance, CXCR4 stimulates the PI3K/Akt pathway and regulates cell-cycle proteins in neurons. [3][4][5][6] Under pathological conditions at least some of these essential CXCR4 functions are compromised, leading to neuronal dysfunction/death. 1,7 Thus, a complete understanding of the effects of CXCR4 activation in the brain has important physiological and pathological implications.Rb is a well-known transcriptional repressor, which controls cell-cycle progression, differentiation/survival, and genomic integrity. Rb is also implicated in fundamental CNS developmental processes such as, neuronal migration, differentiation, and neurite extension. 8,9 The effects of Rb on cell survival are primarily due to regulation of members of the E2F family of transcription factors, though Rb can also directly inactivate proapoptotic proteins, such as pp32.10 E2F proteins stimulate expression of genes promoting cell-cycle progression in proliferating cells, whereas they induce apoptotic genes in differentiated cells, including neurons.11 Rb is phosphorylated at several phosphoacceptor sites by specific kinases. 12 Hence, the immediate effect of Rb phosphorylation is to remove Rb from its specific promoters, leading to inhibition of Rb-dependent gene repression. Rb phosphorylation results in enhanced E2F1 transcriptional activity culminating in death of postmitotic neurons.11 Alterations of Rb/E2F pathway were reported in various neuropathologies, such as Parkinson's and Alzhei...

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Role of the transcription factor E2F1 in CXCR4-mediated neurotoxicity and HIV neuropathology

Cited by 29 publications

References 43 publications

Neuronal ferritin heavy chain and drug abuse affect HIV-associated cognitive dysfunction

Neuronal ferritin heavy chain and drug abuse affect HIV-associated cognitive dysfunction

Bilaminar Co-culture of Primary Rat Cortical Neurons and Glia

The chemokine CXCL12 promotes survival of postmitotic neurons by regulating Rb protein

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