Complement C3a treatment accelerates recovery after stroke via modulation of astrocyte reactivity and cortical connectivity
Anna Stokowska, … , Milos Pekny, Marcela Pekna
Anna Stokowska, … , Milos Pekny, Marcela Pekna
Published March 30, 2023
Citation Information: J Clin Invest. 2023;133(10):e162253. https://doi.org/10.1172/JCI162253.
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Research Article Neuroscience

Complement C3a treatment accelerates recovery after stroke via modulation of astrocyte reactivity and cortical connectivity

Abstract

Despite advances in acute care, ischemic stroke remains a major cause of long-term disability. Approaches targeting both neuronal and glial responses are needed to enhance recovery and improve long-term outcome. The complement C3a receptor (C3aR) is a regulator of inflammation with roles in neurodevelopment, neural plasticity, and neurodegeneration. Using mice lacking C3aR (C3aR–/–) and mice overexpressing C3a in the brain, we uncovered 2 opposing effects of C3aR signaling on functional recovery after ischemic stroke: inhibition in the acute phase and facilitation in the later phase. Peri-infarct astrocyte reactivity was increased and density of microglia reduced in C3aR–/– mice; C3a overexpression led to the opposite effects. Pharmacological treatment of wild-type mice with intranasal C3a starting 7 days after stroke accelerated recovery of motor function and attenuated astrocyte reactivity without enhancing microgliosis. C3a treatment stimulated global white matter reorganization, increased peri-infarct structural connectivity, and upregulated Igf1 and Thbs4 in the peri-infarct cortex. Thus, C3a treatment from day 7 after stroke exerts positive effects on astrocytes and neuronal connectivity while avoiding the deleterious consequences of C3aR signaling during the acute phase. Intranasal administration of C3aR agonists within a convenient time window holds translational promise to improve outcome after ischemic stroke.

Authors

Anna Stokowska, Markus Aswendt, Daniel Zucha, Stephanie Lohmann, Frederique Wieters, Javier Morán Suarez, Alison L. Atkins, YiXian Li, Maria Miteva, Julia Lewin, Dirk Wiedermann, Michael Diedenhofen, Åsa Torinsson Naluai, Pavel Abaffy, Lukas Valihrach, Mikael Kubista, Mathias Hoehn, Milos Pekny, Marcela Pekna

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Figure 5

C3a treatment modulates stroke-induced astrocyte responses in peri-infarct cortex.

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C3a treatment modulates stroke-induced astrocyte responses in peri-infar...
(A) Experimental design. Ctx, cortex; CL, contralesional; IL, ipsilesional. (B) Volcano plot showing genes differentially expressed (adjusted P value < 0.1) in peri-infarct cortex of C3a- versus PBS-treated mice on P14. Green boxes indicate reactivity markers characteristic of DAAs. (C) Gene set enrichment analysis of differentially expressed genes in peri-infarct cortex of C3a- versus PBS-treated mice at P14. (D) Heatmap of cell type fractions estimated by deconvolution analysis. (E) Heatmap of astrocyte subpopulation fractions estimated by deconvolution analysis. Values in heatmap cells are group averages. (F) Sample variance and statistical analysis for the estimated contribution of the DAA and GFAPlo subpopulations. n = 4 per group and time point. (G) Gene ontologies for the most highly expressed genes (gene expression profile score > 90 counts per million) in DAAs (top) and GFAPlo astrocytes (bottom). FDR, false discovery rate. (H) Representative images of P21 peri-infarct cortex immunostained with antibodies against GFAP and vimentin (Vim) and the fraction of GFAP-positive astrocytes with overlapping Vim immunoreactivity in PBS- and C3a-treated mice on P21. PBS, n = 10; C3a, n = 10. Scale bars: 50 μm (upper), 10 μm (lower). Bar plots represent mean ± SEM. Two-way ANOVA with Holm-Šidák post hoc test (F and H): *P < 0.05, **P < 0.01, ****P < 0.0001 for IL vs. CL comparisons; #P < 0.05, ##P < 0.01, ###P < 0.001, ####P < 0.0001 for comparisons between treatments and time points.