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Updated: Mar 12, 2026
Isolation and Flow Cytometric Assessment of Neuroimmune Interactions in a Mini-Stroke Murine Model
Published on: June 20, 2025
In vivo inhibition of miR-155 significantly alters post-stroke inflammatory response
Juan Carlos Pena-Philippides1, Ernesto Caballero-Garrido1, Tamar Lordkipanidze2
1Department of Neurosurgery, University of New Mexico Health Sciences Center, 1101 Yale Blvd, Albuquerque, NM, 87106-3834, USA.
Background:
MicroRNA miR-155 is implicated in modulation of the inflammatory processes in various pathological conditions. In our previous studies, we demonstrated that in vivo inhibition of miR-155 promotes functional recovery after mouse experimental stroke. In the present study, we explored if this beneficial effect is associated with miR-155 inhibition-induced alterations in post-stroke inflammatory response.
Methods:
Intravenous injections of a specific miR-155 inhibitor were initiated at 48 h after mouse distal middle cerebral artery occlusion (dMCAO). Temporal changes in the expression of cytokines and key molecules associated with cytokine signaling were assessed at 7, 14, and 21 days after dMCAO, using mouse cytokine gene and protein arrays and Western blot analyses. Electron and immunofluorescence confocal microscopy techniques were used to evaluate the ultrastructural changes, as well as altered expression of specific phenotypic markers, at different time points after dMCAO.
Results:
In the inhibitor-injected mice (inhibitor group), there was a significant decrease in CCL12 and CXCL3 cytokine expression at 7 days and significantly increased levels of major cytokines IL-10, IL-4, IL-6, MIP-1α, IL-5, and IL-17 at 14 days after dMCAO. These temporal changes correlated with altered expression of miR-155 target proteins SOCS-1, SHIP-1, and C/EBP-β and phosphorylation levels of cytokine signaling regulator STAT-3. Electron microscopy showed decreased number of phagocytically active peri-vascular microglia/macrophages in the inhibitor samples. Immunofluorescence and Western blot of these samples demonstrated that expression of leukocyte/ macrophage marker CD45 and phagocytosis marker CD68 was reduced at 7 days, and in contrast, significantly increased at 14 days after dMCAO, as compared to controls.
Conclusions:
Based on our findings, we propose that in vivo miR-155 inhibition following mouse stroke significantly alters the time course of the expression of major cytokines and inflammation-associated molecules, which could influence inflammation process and tissue repair after experimental cerebral ischemia.
Insights
Inhibiting microRNA 155 (miR-155) after experimental stroke in mice alters inflammatory responses. This modulation of cytokines and immune cells suggests a potential therapeutic strategy for stroke recovery.
Area of Science:
- Neuroscience
- Immunology
- Molecular Biology
Background:
- MicroRNA miR-155 plays a role in inflammatory processes across various diseases.
- Previous research indicated that inhibiting miR-155 in vivo improves functional recovery post-stroke in mice.
- This study investigates the link between miR-155 inhibition and changes in the post-stroke inflammatory response.
Purpose of the Study:
- To explore how inhibiting miR-155 affects the inflammatory response after experimental stroke.
- To understand the temporal changes in cytokine expression and signaling molecules following miR-155 inhibition post-stroke.
Main Methods:
- Mice underwent distal middle cerebral artery occlusion (dMCAO) to model stroke.
- A specific miR-155 inhibitor was administered intravenously 48 hours post-dMCAO.
- Cytokine expression, signaling molecules, and cellular markers were analyzed at 7, 14, and 21 days using gene/protein arrays, Western blot, and microscopy.
Main Results:
- miR-155 inhibition led to decreased CCL12 and CXCL3 expression at 7 days post-stroke.
- Increased levels of IL-10, IL-4, IL-6, MIP-1α, IL-5, and IL-17 were observed at 14 days.
- Changes correlated with altered expression of miR-155 targets (SOCS-1, SHIP-1, C/EBP-β) and STAT-3 phosphorylation.
- Reduced CD45 and CD68 expression at 7 days, with increased expression at 14 days, indicated altered immune cell activity.
Conclusions:
- In vivo miR-155 inhibition significantly modifies the temporal expression of cytokines and inflammation-related molecules post-stroke.
- These alterations in the inflammatory cascade may influence tissue repair and recovery following cerebral ischemia.
