NMDA-induced neuronal survival is mediated through nuclear factor I-A in mice
Sika Zheng, Stephen M. Eacker, Suk Jin Hong, Richard M. Gronostajski, Ted M. Dawson, Valina L. Dawson
Sika Zheng, Stephen M. Eacker, Suk Jin Hong, Richard M. Gronostajski, Ted M. Dawson, Valina L. Dawson
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Research Article Neuroscience

NMDA-induced neuronal survival is mediated through nuclear factor I-A in mice

Abstract

Identification of the signaling pathways that mediate neuronal survival signaling could lead to new therapeutic targets for neurologic disorders and stroke. Sublethal doses of NMDA can induce robust endogenous protective mechanisms in neurons. Through differential analysis of primary library expression and microarray analyses, here we have shown that nuclear factor I, subtype A (NFI-A), a member of the NFI/CAAT-box transcription factor family, is induced in mouse neurons by NMDA receptor activation in a NOS- and ERK-dependent manner. Knockdown of NFI-A induction using siRNA substantially reduced the neuroprotective effects of sublethal doses of NMDA. Further analysis indicated that NFI-A transcriptional activity was required for the neuroprotective effects of NMDA receptor activation. Additional evidence of the neuroprotective effects of NFI-A was provided by the observations that Nfia–/– neurons were highly sensitive to NMDA-induced excitotoxicity and were more susceptible to developmental cell death than wild-type neurons and that Nfia+/– mice were more sensitive to NMDA-induced intrastriatal lesions than were wild-type animals. These results identify NFI-A as what we believe to be a novel neuroprotective transcription factor with implications in neuroprotection and neuronal plasticity following NMDA receptor activation.

Authors

Sika Zheng, Stephen M. Eacker, Suk Jin Hong, Richard M. Gronostajski, Ted M. Dawson, Valina L. Dawson

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Figure 4

NFI-A protects neurons through its transcriptional activity.

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NFI-A protects neurons through its transcriptional activity. (A) Schemat...
(A) Schematic representation of NFI luciferase reporter (NFI LUC), which was generated from the basic luciferase reporter (Tal LUC) by inserting triplicate NFI response elements (TTGGCACGGAGCCAA) upstream of the basal transcriptional Tal promoter. NFI-A DBM is a DNA-binding mutant with 3 cysteine residues (Cys2, Cys4, Cys5) in the DNA-binding domain mutated to serine residues. NFI-A DBD is a deletion mutant in which the whole DNA-binding domain was truncated. (B) Luciferase activity in neurons transfected with combinations of NFI-A, NFI-A mutants, or luciferase reporters. Experiments were replicated at least 3 times. *P < 0.01, 1-way ANOVA followed by Tukey-Kramer post-hoc test. (C) Luciferase activity following 50 μM NMDA treatment in primary cortical cultures transfected with NFI LUC or Tal LUC. Experiments were replicated at least 3 times. (D) Neuronal viability after 500 μM NMDA excitotoxicity treatment in primary cortical cultures transfected with NFI-A, NFI-A mutants, or control vector (pCHA) and cotransfected with a GFP plasmid. Experiments were replicated at least 4 times. *P < 0.01, 1-way ANOVA followed by Tukey-Kramer post-hoc test, compared with control vector (pCHA), NFI-A DBM, or NFI-A DBD. (E) Immunoblot analysis of NFI-A, NFI-A DBM, and NFI-A DBD showing similar levels of expression in SHSY5Y cells 24 hours after plasmid transfection. Experiments were replicated 3 times. (F) Quantification of immunoblot analysis in E by laser densitometry.