Chemical inhibition of FBXO7 reduces inflammation and confers neuroprotection by stabilizing the mitochondrial kinase PINK1
Yuan Liu, … , Bill B. Chen, Rama K. Mallampalli
Yuan Liu, … , Bill B. Chen, Rama K. Mallampalli
Published June 4, 2020
Citation Information: JCI Insight. 2020;5(11):e131834. https://doi.org/10.1172/jci.insight.131834.
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Research Article Neuroscience

Chemical inhibition of FBXO7 reduces inflammation and confers neuroprotection by stabilizing the mitochondrial kinase PINK1

Abstract

Mitochondrial quality control is mediated by the PTEN-induced kinase 1 (PINK1), a cytoprotective protein that is dysregulated in inflammatory lung injury and neurodegenerative diseases. Here, we show that a ubiquitin E3 ligase receptor component, FBXO7, targets PINK1 for its cellular disposal. FBXO7, by mediating PINK1 ubiquitylation and degradation, was sufficient to induce mitochondrial injury and inflammation in experimental pneumonia. A computational simulation–based screen led to the identification of a small molecule, BC1464, which abrogated FBXO7 and PINK1 association, leading to increased cellular PINK1 concentrations and activities, and limiting mitochondrial damage. BC1464 exerted antiinflammatory activity in human tissue explants and murine lung inflammation models. Furthermore, BC1464 conferred neuroprotection in primary cortical neurons, human neuroblastoma cells, and patient-derived cells in several culture models of Parkinson’s disease. The data highlight a unique opportunity to use small molecule antagonists that disrupt PINK1 interaction with the ubiquitin apparatus to enhance mitochondrial quality, limit inflammatory injury, and maintain neuronal viability.

Authors

Yuan Liu, Travis B. Lear, Manish Verma, Kent Z.Q. Wang, P. Anthony Otero, Alison C. McKelvey, Sarah R. Dunn, Erin Steer, Nicholas W. Bateman, Christine Wu, Yu Jiang, Nathaniel M. Weathington, Mauricio Rojas, Charleen T. Chu, Bill B. Chen, Rama K. Mallampalli

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Figure 5

Fbxo7 FP domain small molecule inhibitor accumulates PINK1 protein.

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Fbxo7 FP domain small molecule inhibitor accumulates PINK1 protein. (A) ...
(A) Structural analysis of the Fbxo7 FP domain. Docking study of a candidate inhibitor BC1464 within the Fbxo7-FP domain suggests hydrophilic interactions of residues GLN215, LYS235, and LYS266 with BC1464. (B) His pull down Fbxo7 protein was exposed to BC1464 at indicated concentrations. TnT-synthesized PINK1 protein was then incubated with drug-bound Fbxo7 beads overnight. The eluate was subjected to immunoblotting. The relative amounts of PINK1 detected in the pull-downs were normalized to loading and quantified; data are shown as means ± SEM (n = 3). (C) BEAS-2B cells were incubated with BC1464 or the control compound BC1465 at the indicated concentrations for 16 hours before immunoblotting. (D) BEAS-2B cells were pretreated with BC1464 or BC1465 (1 μg/mL) for 16 hours, and the cells were then incubated with CHX (40 μg/mL). The cells were collected at indicated time points for immunoblot analysis. (E) BEAS-2B cells were nucleofected with control or Fbxo7 siRNA (50 pg) and incubated for 72 hours. BC1464 was then administrated at indicated concentration for an additional 18-hour incubation. The cell lysates were subjected to immunoblotting.