Homotopic contralesional excitation suppresses spontaneous circuit repair and global network reconnections following ischemic stroke
Abstract
Understanding circuit-level manipulations that affect the brain's capacity for plasticity will inform the design of targeted interventions that enhance recovery after stroke. Following stroke, increased contralesional activity (e.g. use of the unaffected limb) can negatively influence recovery, but it is unknown which specific neural connections exert this influence, and to what extent increased contralesional activity affects systems- and molecular-level biomarkers of recovery. Here, we combine optogenetic photostimulation with optical intrinsic signal imaging (OISI) to examine how contralesional excitatory activity affects cortical remodeling after stroke in mice. Following photothrombosis of left primary somatosensory forepaw (S1FP) cortex, mice either recovered spontaneously or received chronic optogenetic excitation of right S1FP over the course of 4 weeks. Contralesional excitation suppressed perilesional S1FP remapping and was associated with abnormal patterns of stimulus-evoked activity in the unaffected limb. This maneuver also prevented the restoration of resting-state functional connectivity (RSFC) within the S1FP network, RSFC in several networks functionally-distinct from somatomotor regions, and resulted in persistent limb-use asymmetry. In stimulated mice, perilesional tissue exhibited transcriptional changes in several genes relevant for recovery. Our results suggest that contralesional excitation impedes local and global circuit reconnection through suppression of cortical activity and several neuroplasticity-related genes after stroke, and highlight the importance of site selection for therapeutic intervention after focal ischemia.
Data availability
Data reported in Figures 1, 6, 7 are publicly available:Fig. 1: https://figshare.com/articles/dataset/Cylinder_Rearing_Scores/19773487Fig. 6: https://figshare.com/articles/dataset/Neuroimaging_Data_Pre_Post_Stroke_for_26-03-2021-RA-eLife-68852/19773244Fig. 7: https://figshare.com/articles/dataset/RT-PCR_Data/19773364Data reported in Figures 2, 3, 4, 5 are unavailable due to technical issues with storage hard drives.Analysis code is available at https://github.com/BauerLabCodebase
Article and author information
Author details
Funding
National Institutes of Health (R01NS102870)
- Adam Q Bauer
National Institutes of Health (F31NS103275)
- Zachary Pollack Rosenthal
McDonnell Center for Systems Neuroscience
- Adam Q Bauer
The Alborada Trust
- Tadeusz Wieloch
The Wachtmeister Foundation
- Tadeusz Wieloch
Swedish Research Council
- Tadeusz Wieloch
National Institutes of Health (K25NS083754)
- Adam Q Bauer
National Institutes of Health (R37NS110699)
- Jin-Moo Lee
National Institutes of Health (R01NS084028)
- Jin-Moo Lee
National Institutes of Health (R01NS094692)
- Jin-Moo Lee
National Institutes of Health (R01NS078223)
- Joseph P Culver
National Institutes of Health (P01NS080675)
- Joseph P Culver
National Institutes of Health (R01NS099429)
- Joseph P Culver
National Institutes of Health (F31NS089135)
- Andrew W Kraft
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Mackenzie W Mathis, EPFL, Switzerland
Ethics
Animal experimentation: All procedures described below were approved by theWashington University Animal Studies Committee in compliance with theAmerican Association for Accreditation of Laboratory Animal Care guidelines (Protocol #20-0022)
Version history
- Received: March 27, 2021
- Preprint posted: May 2, 2021 (view preprint)
- Accepted: June 14, 2022
- Accepted Manuscript published: June 20, 2022 (version 1)
- Version of Record published: July 28, 2022 (version 2)
Copyright
© 2022, Bice et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 1,241
- views
-
- 300
- downloads
-
- 13
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Further reading
-
- Neuroscience
Abnormal activity in the cerebellar nuclei can be used to predict motor symptoms and induce them experimentally, pointing to potential therapeutic strategies.
-
- Cell Biology
- Neuroscience
One of the most extensively studied members of the Ras superfamily of small GTPases, Rac1 is an intracellular signal transducer that remodels actin and phosphorylation signaling networks. Previous studies have shown that Rac1-mediated signaling is associated with hippocampal-dependent working memory and longer-term forms of learning and memory and that Rac1 can modulate forms of both pre- and postsynaptic plasticity. How these different cognitive functions and forms of plasticity mediated by Rac1 are linked, however, is unclear. Here, we show that spatial working memory in mice is selectively impaired following the expression of a genetically encoded Rac1 inhibitor at presynaptic terminals, while longer-term cognitive processes are affected by Rac1 inhibition at postsynaptic sites. To investigate the regulatory mechanisms of this presynaptic process, we leveraged new advances in mass spectrometry to identify the proteomic and post-translational landscape of presynaptic Rac1 signaling. We identified serine/threonine kinases and phosphorylated cytoskeletal signaling and synaptic vesicle proteins enriched with active Rac1. The phosphorylated sites in these proteins are at positions likely to have regulatory effects on synaptic vesicles. Consistent with this, we also report changes in the distribution and morphology of synaptic vesicles and in postsynaptic ultrastructure following presynaptic Rac1 inhibition. Overall, this study reveals a previously unrecognized presynaptic role of Rac1 signaling in cognitive processes and provides insights into its potential regulatory mechanisms.