Kv1.3 modulates neuroinflammation and neurodegeneration in Parkinson’s disease
Souvarish Sarkar, … , Heike Wulff, Anumantha G. Kanthasamy
Souvarish Sarkar, … , Heike Wulff, Anumantha G. Kanthasamy
Published June 29, 2020
Citation Information: J Clin Invest. 2020;130(8):4195-4212. https://doi.org/10.1172/JCI136174.
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Research Article Inflammation Neuroscience

Kv1.3 modulates neuroinflammation and neurodegeneration in Parkinson’s disease

Abstract

Characterization of the key cellular targets contributing to sustained microglial activation in neurodegenerative diseases, including Parkinson’s disease (PD), and optimal modulation of these targets can provide potential treatments to halt disease progression. Here, we demonstrated that microglial Kv1.3, a voltage-gated potassium channel, was transcriptionally upregulated in response to aggregated α-synuclein (αSynAgg) stimulation in primary microglial cultures and animal models of PD, as well as in postmortem human PD brains. Patch-clamp electrophysiological studies confirmed that the observed Kv1.3 upregulation translated to increased Kv1.3 channel activity. The kinase Fyn, a risk factor for PD, modulated transcriptional upregulation and posttranslational modification of microglial Kv1.3. Multiple state-of-the-art analyses, including Duolink proximity ligation assay imaging, revealed that Fyn directly bound to Kv1.3 and posttranslationally modified its channel activity. Furthermore, we demonstrated the functional relevance of Kv1.3 in augmenting the neuroinflammatory response by using Kv1.3-KO primary microglia and the Kv1.3-specific small-molecule inhibitor PAP-1, thus highlighting the importance of Kv1.3 in neuroinflammation. Administration of PAP-1 significantly inhibited neurodegeneration and neuroinflammation in multiple animal models of PD. Collectively, our results imply that Fyn-dependent regulation of Kv1.3 channels plays an obligatory role in accentuating the neuroinflammatory response in PD and identify Kv1.3 as a potential therapeutic target for PD.

Authors

Souvarish Sarkar, Hai M. Nguyen, Emir Malovic, Jie Luo, Monica Langley, Bharathi N. Palanisamy, Neeraj Singh, Sireesha Manne, Matthew Neal, Michelle Gabrielle, Ahmed Abdalla, Poojya Anantharam, Dharmin Rokad, Nikhil Panicker, Vikrant Singh, Muhammet Ay, Adhithiya Charli, Dilshan Harischandra, Lee-Way Jin, Huajun Jin, Srikant Rangaraju, Vellareddy Anantharam, Heike Wulff, Anumantha G. Kanthasamy

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Figure 1

Upregulated expression of the potassium channel Kv1.3 upon aggregated αSyn stimulation in microglial cells in vitro.

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Upregulated expression of the potassium channel Kv1.3 upon aggregated αS...
(A) Whole-cell patch-clamp recordings of PMCs treated with 1 μM αSynAgg for 24–48 hours, showing αSynAgg-induced increased Kv1.3 activity (control n = 24 and αSynAgg n = 12). Kv1.3 was identified by its characteristic use dependence, which was revealed when applying a train of ten 200-ms pulses from –80 to 40 mV at 1-second intervals (1 Hz). (B) qRT-PCR showing that αSynAgg induced Kv1.3 mRNA expression without significantly altering other potassium channels. (C) Western blot of αSynAgg-induced Kv1.3 protein expression in PMCs. (D) ICC of αSynAgg-induced Kv1.3 protein expression in PMCs. Scale bar: 100 μm. (E) Flow cytometric analysis of immortalized MMCs treated with 1 μM αSynAgg for 24 hours, showing αSynAgg-induced Kv1.3 surface expression. (F) qRT-PCR of human microglia treated with LPS (1 μg/mL) and IL-4 (20 ng/mL) for 6 hours, showing LPS-induced Kv1.3 expression. A 1-way ANOVA was used to compare multiple groups. In most cases, Tukey’s post hoc analysis was applied in B and F. A 2-tailed Student’s t test was used for all other figures when comparing 2 groups. Each dot on the bar graphs represents a biological replicate. Data are presented as the mean ± SEM, with 3–5 biological replicates from 2–3 independent experiments unless otherwise noted. *P ≤ 0.05, **P < 0.01, and ***P < 0.001.