The NR4A2/VGF pathway fuels inflammation-induced neurodegeneration via promoting neuronal glycolysis
Marcel S. Woo, … , Doron Merkler, Manuel A. Friese
Marcel S. Woo, … , Doron Merkler, Manuel A. Friese
Published August 15, 2024
Citation Information: J Clin Invest. 2024;134(16):e177692. https://doi.org/10.1172/JCI177692.
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Research Article Inflammation Neuroscience

The NR4A2/VGF pathway fuels inflammation-induced neurodegeneration via promoting neuronal glycolysis

Abstract

A disturbed balance between excitation and inhibition (E/I balance) is increasingly recognized as a key driver of neurodegeneration in multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system. To understand how chronic hyperexcitability contributes to neuronal loss in MS, we transcriptionally profiled neurons from mice lacking inhibitory metabotropic glutamate signaling with shifted E/I balance and increased vulnerability to inflammation-induced neurodegeneration. This revealed a prominent induction of the nuclear receptor NR4A2 in neurons. Mechanistically, NR4A2 increased susceptibility to excitotoxicity by stimulating continuous VGF secretion leading to glycolysis-dependent neuronal cell death. Extending these findings to people with MS (pwMS), we observed increased VGF levels in serum and brain biopsies. Notably, neuron-specific deletion of Vgf in a mouse model of MS ameliorated neurodegeneration. These findings underscore the detrimental effect of a persistent metabolic shift driven by excitatory activity as a fundamental mechanism in inflammation-induced neurodegeneration.

Authors

Marcel S. Woo, Lukas C. Bal, Ingo Winschel, Elias Manca, Mark Walkenhorst, Bachar Sevgili, Jana K. Sonner, Giovanni Di Liberto, Christina Mayer, Lars Binkle-Ladisch, Nicola Rothammer, Lisa Unger, Lukas Raich, Alexandros Hadjilaou, Barbara Noli, Antonio L. Manai, Vanessa Vieira, Nina Meurs, Ingrid Wagner, Ole Pless, Cristina Cocco, Samuel B. Stephens, Markus Glatzel, Doron Merkler, Manuel A. Friese

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Figure 1

NR4A2 is induced in Grm8-deficient neurons.

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NR4A2 is induced in Grm8-deficient neurons. (A) The number of Grm8+ neur...
(A) The number of Grm8+ neurons assessed by RNAScope in cervical spinal cords of healthy and EAE mice 15 days after immunization (n = 5). Scale bar: 20 μm. (B) Heatmap of top 15 up and downregulated genes in NeuN+ cortical nuclei of Grm8–/– compared with WT mice (n = 3). (C) Relative Nr4a2 expression in NeuN+ cortical nuclei of Grm8–/– and WT mice in relative units (RU). (D) Nr4a2 expression (RU) in WT and Grm8–/– primary cortical neurons (PCNs; n = 5). Paired t test was performed. (E) NR4A2 mean fluorescence intensity (MFI) in cortical neuronal nuclei estimated by flow cytometry of WT (n = 4) and Grm8–/– mice (n = 5). (F and G) Nr4a2 expression (RU) in WT (F) and Grm8–/– (G) PCNs after glutamate stimulation (n = 5). Paired t test was performed. (H) NR4A2 MFI in PCNs that were treated with glutamate and vehicle, 2 mM EDTA or 50 μM 2-APB (n = 6). Scale bar: 20 μm. (I) Dead cells per field of view (FOV) of control (mScarlet) or Nr4a2-overexpressing PCNs 7 days after transduction (D.A.T.; left) and 14 D.A.T. (right). PCNs were treated with vehicle or 1 μM AZ12216052 every other day (n = 5). (J and K) Viability (RU) of control (mScarlet) or Nr4a2-overexpressing PCNs that were exposed to glutamate and vehicle or 1 μM AZ12216052 (n = 5, J) or 50 nM Ip7e (n = 5; K). (L) Calcium traces and somatic calcium accumulation in glutamate-treated control (mScarlet) or Nr4a2-overexpressing PCNs (n = 4). Points represent individual experiments, additionally, the mean is shown. If not stated otherwise, unpaired t test with FDR correction for multiple comparisons was used. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.