TY - JOUR TI - Soluble α-synuclein–antibody complexes activate the NLRP3 inflammasome in hiPSC-derived microglia AU - Trudler, Dorit AU - Nazor, Kristopher L. AU - Eisele, Yvonne S. AU - Grabauskas, Titas AU - Dolatabadi, Nima AU - Parker, James AU - Sultan, Abdullah AU - Zhong, Zhenyu AU - Goodwin, Marshall S. AU - Levites, Yona AU - Golde, Todd E. AU - Kelly, Jeffery W. AU - Sierks, Michael R. AU - Schork, Nicholas J. AU - Karin, Michael AU - Ambasudhan, Rajesh AU - Lipton, Stuart A. T2 - Proceedings of the National Academy of Sciences AB - Parkinson’s disease is characterized by accumulation of α-synuclein (αSyn). Release of oligomeric/fibrillar αSyn from damaged neurons may potentiate neuronal death in part via microglial activation. Heretofore, it remained unknown if oligomeric/fibrillar αSyn could activate the nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome in human microglia and whether anti-αSyn antibodies could prevent this effect. Here, we show that αSyn activates the NLRP3 inflammasome in human induced pluripotent stem cell (hiPSC)-derived microglia (hiMG) via dual stimulation involving Toll-like receptor 2 (TLR2) engagement and mitochondrial damage. In vitro, hiMG can be activated by mutant (A53T) αSyn secreted from hiPSC-derived A9-dopaminergic neurons. Surprisingly, αSyn–antibody complexes enhanced rather than suppressed inflammasome-mediated interleukin-1β (IL-1β) secretion, indicating these complexes are neuroinflammatory in a human context. A further increase in inflammation was observed with addition of oligomerized amyloid-β peptide (Aβ) and its cognate antibody. In vivo, engraftment of hiMG with αSyn in humanized mouse brain resulted in caspase-1 activation and neurotoxicity, which was exacerbated by αSyn antibody. These findings may have important implications for antibody therapies aimed at depleting misfolded/aggregated proteins from the human brain, as they may paradoxically trigger inflammation in human microglia. Author Information Dorit Trudlera,b,c, Kristopher L. Nazord, Yvonne S. Eiselee,f, Titas Grabauskasa,b, Nima Dolatabadia,b,c, James Parkerc, Abdullah Sultanc, Zhenyu Zhongg,h,i, Marshall S. Goodwinj,k,l, Yona Levitesj,k,l, Todd E. Goldej,k,l, Jeffery W. Kellya,b,e, Michael R. Sierksm, Nicholas J. Schorkn,o,p,q, Michael Karing,h,1, Rajesh Ambasudhana,b,c,1,2, and Stuart A. Liptona,b,c,r,s,1,2aNeurodegeneration New Medicines Center, The Scripps Research Institute, La Jolla, CA 92037;bDepartment of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037;cNeurodegenerative Disease Center, Scintillon Institute, San Diego, CA 92121;dMYi Diagnostics & Discovery, San Diego, CA 92121;eDepartment of Chemistry, The Scripps Research Institute, La Jolla, CA 92037;fDivision of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15219;gDepartment of Pharmacology, University of California San Diego School of Medicine, La Jolla, CA 92093;hDepartment of Pathology, University of California San Diego School of Medicine, La Jolla, CA 92093;iDepartment of Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390;jDepartment of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610;kCenter for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610;lMcKnight Brain Institute, University of Florida, Gainesville, FL 32610;mDepartment of Chemical Engineering, Arizona State University, Tempe, AZ 85287;nQuantitative Medicine & Systems Biology Division, Translational Genomics Research Institute, Phoenix, AZ 85004;oDepartment of Psychiatry, University of California San Diego, La Jolla, CA 92037;pDepartment of Family Medicine and Public Health, University of California San Diego, La Jolla, CA 92037;qDepartment of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037;rDepartment of Neuroscience, The Scripps Research Institute, La Jolla, CA 92037;sDepartment of Neurosciences, University of California San Diego School of Medicine, La Jolla, CA 92093Contributed by Michael Karin, February 17, 2021 (sent for review February 5, 2021; reviewed by Hilmar Bading and Giles Hardingham) Footnotes↵1To whom correspondence may be addressed. Email: mkarin@ucsd.edu, rajesh@scintillon.edu, or slipton@scripps.edu.↵2R.A. and S.A.L. contributed equally to this work.Author contributions: D.T., R.A., and S.A.L. designed research; D.T., Y.S.E., T.G., N.D., J.P., and A.S. performed research; K.L.N., Y.S.E., Z.Z., M.S.G., Y.L., T.E.G., J.W.K., M.R.S., N.J.S., and M.K. contributed new reagents/analytic tools; D.T., K.L.N., R.A., and S.A.L. analyzed data; R.A. and S.A.L. supervised the work; and D.T., R.A., and S.A.L. wrote the paper.Reviewers: H.B., Heidelberg University; and G.H., University of Edinburgh.Competing interest statement: S.A.L. and G.H. are coauthors on a published consensus statement review of cell-death criteria along with several dozen other authors who are authorities in this field [N. M. C. Connolly et al., Cell Death Differ. 25, 542–572 (2018)]. That manuscript was published in order to help nonexperts in the field understand and use criteria for various types of cell death. They also published a similar type of review paper together 10 y ago [G. E. Hardingham, S. A. Lipton, Antioxid. Redox Signal. 14, 1421–1424 (2011)]. However, S.A.L. and G.H. have never formally collaborated or worked together on any laboratory-based scientific project, including the current work.This article contains supporting information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2025847118/-/DCSupplemental. DA - 2021/04/13/ PY - 2021 DO - 10.1073/pnas.2025847118 DP - www.pnas.org VL - 118 IS - 15 J2 - PNAS LA - en SN - 0027-8424, 1091-6490 UR - https://www.pnas.org/content/118/15/e2025847118 Y2 - 2021/04/08/22:45:12 KW - Alzheimer’s disease KW - Lewy body dementia KW - Parkinson’s disease KW - antibody therapies KW - neuroinflammation ER -