Norepinephrine metabolite DOPEGAL activates AEP and pathological Tau aggregation in locus coeruleus
Seong Su Kang, … , David Weinshenker, Keqiang Ye
Seong Su Kang, … , David Weinshenker, Keqiang Ye
Published December 3, 2019
Citation Information: J Clin Invest. 2020;130(1):422-437. https://doi.org/10.1172/JCI130513.
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Research Article Cell biology Neuroscience

Norepinephrine metabolite DOPEGAL activates AEP and pathological Tau aggregation in locus coeruleus

Abstract

Aberrant Tau inclusions in the locus coeruleus (LC) are the earliest detectable Alzheimer’s disease–like (AD-like) neuropathology in the human brain. However, why LC neurons are selectively vulnerable to developing early Tau pathology and degenerating later in disease and whether the LC might seed the stereotypical spread of Tau pathology to the rest of the brain remain unclear. Here, we show that 3,4-dihydroxyphenylglycolaldehyde, which is produced exclusively in noradrenergic neurons by monoamine oxidase A metabolism of norepinephrine, activated asparagine endopeptidase that cleaved Tau at residue N368 into aggregation- and propagation-prone forms, thus leading to LC degeneration and the spread of Tau pathology. Activation of asparagine endopeptidase–cleaved Tau aggregation in vitro and in intact cells was triggered by 3,4-dihydroxyphenylglycolaldehyde, resulting in LC neurotoxicity and propagation of pathology to the forebrain. Thus, our findings reveal that norepinephrine metabolism and Tau cleavage represent the specific molecular mechanism underlying the selective vulnerability of LC neurons in AD.

Authors

Seong Su Kang, Xia Liu, Eun Hee Ahn, Jie Xiang, Fredric P. Manfredsson, Xifei Yang, Hongbo R. Luo, L. Cameron Liles, David Weinshenker, Keqiang Ye

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Figure 1

The NE metabolite DOPEGAL triggers Tau aggregation in vitro.

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The NE metabolite DOPEGAL triggers Tau aggregation in vitro. (A) Recombi...
(A) Recombinant Tau (rTau) or rTau N368 (1 μg) was incubated with DOPEGAL (0, 5, 50, or 500 μM) for 24 hours, and aggregation was detected by Western blot using Tau5 antibody. (B) rTau (1 μg) was incubated with vehicle, DA, NE, DOPAL, or DOPEGAL (500 μM) for 24 hours, and aggregation was detected by Western blot using Tau5 antibody. (C) rTau (1 μg) was incubated with vehicle or DOPEGAL, and ThioT assay was used to evaluate the kinetics of aggregation of Tau over 120 hours. SH-SY5Y cells were infected with hTau virus, then exposed to DA, NE, DOPAL, or DOPEGAL (60 μM) for 24 hours. (D) Western blot analysis was conducted with cell lysates using antibodies against AEP and different forms of Tau. (E) AEP activity was analyzed by the enzymatic assay. Data are shown as mean ± SEM (n = 3 per group). *P < 0.05 and **P < 0.01, by 1-way ANOVA. Cell death was analyzed by LDH assay (F) and propidium iodide staining (G–H). Scale bar: 50 μm. Data are shown as the mean ± SEM (n = 3 per group). *P < 0.05 and **P < 0.01, by 1-way ANOVA. Primary cortical neurons were cultured from Tau+/+ and Tau–/– mice and exposed to vehicle or DOPEGAL (60 μM) for 24 hours. (I) Western blot analysis was conducted with cell lysates using antibodies against AEP and different forms of Tau. (J) AEP activity was analyzed by the enzymatic assay. Data are shown as the mean ± SEM (n = 3 per group). *P < 0.05 and **P < 0.01, by 2-tailed t test. Cell death was analyzed by LDH assay (K) and propidium iodide staining (L and M). Scale bar: 50 μm. Data are shown as the mean ± SEM (n = 3 per group). *P < 0.05 and **P < 0.01, by 2-way ANOVA.