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Updated: Aug 30, 2025
Isolation and Flow Cytometric Assessment of Neuroimmune Interactions in a Mini-Stroke Murine Model
Published on: June 20, 2025
MicroRNA-29b Suppresses Inflammation and Protects Blood-Brain Barrier Integrity in Ischemic Stroke
Xiaoqing Ma1,2, Ho Jun Yun3, Kenneth Elkin3
1Department of Neurology, The Affiliated Hospital of Qingdao University, No. 16 Jiangsu Road, Qingdao, China.
Objectives:
Following cerebral ischemia, microRNA- (miR-) 29b in circulating blood is downregulated. This study investigates the underlying mechanism and implications of miR-29b in leukocyte induction.
Methods:
miR-29b from stroke patients and rats with middle cerebral artery occlusion (MCAO) were assessed using real-time polymerase chain reaction (PCR). miR-29b agomir was used to increase miR-29b expression in leukocytes via intravenous injection. C1q and tumor necrosis factor (C1QTNF) 6, interleukin- (IL-) 1β, zonula occludens- (ZO-) 1, occludin, and ischemic outcomes were assessed in MCAO rats. Additionally, hCMEC/D3 cells were subjected to oxygen-glucose deprivation (OGD) and cocultured with HL-60 cells.
Results:
miR-29b levels in neutrophils were found to be significantly lower in stroke patients compared with healthy controls, which may indicate its high diagnostic sensitivity and specificity for stroke. Moreover, miR-29b levels in leukocytes showed a negative correlation with National Institute of Health Stroke Scale (NIHSS) scores and C1QTNF6 levels. In MCAO rats, miR-29b overexpression reduced brain infarct volume and brain edema, decreasing IL-1β levels in leukocytes and in the brain 24 hours poststroke. miR-29b attenuated IL-1β expression via C1QTNF6 inhibition, leading to decreased blood-brain barrier (BBB) disruption and leukocyte infiltration. Moreover, miR-29b overexpression in HL-60 cells downregulated OGD-induced hCMEC/D3 cell apoptosis and increased ZO-1 and occludin levels in vitro.
Conclusion:
Leukocytic miR-29b attenuates inflammatory response by augmenting BBB integrity through C1QTNF6, suggesting a novel miR-29b-based therapeutic therapy for ischemic stroke.
Insights
MicroRNA-29b (miR-29b) is downregulated in stroke patients. Restoring miR-29b in leukocytes reduces inflammation and protects the blood-brain barrier, offering a potential therapy for ischemic stroke.
Area of Science:
- Biomedical Science
- Molecular Biology
- Neuroscience
Background:
- Cerebral ischemia leads to decreased circulating microRNA-29b (miR-29b).
- The role of miR-29b in leukocyte function following stroke is not fully understood.
Purpose of the Study:
- To investigate the mechanism and therapeutic potential of miR-29b in leukocyte induction after ischemic stroke.
Main Methods:
- Assessed miR-29b levels in stroke patients and MCAO rats using real-time PCR.
- Overexpressed miR-29b in leukocytes via agomir injection in MCAO rats.
- Evaluated inflammatory markers, blood-brain barrier integrity, and ischemic outcomes.
Main Results:
- Lower miR-29b levels in neutrophils of stroke patients, correlating negatively with stroke severity (NIHSS) and C1QTNF6.
- miR-29b overexpression reduced infarct volume, brain edema, and IL-1β levels in MCAO rats.
- miR-29b attenuated IL-1β via C1QTNF6 inhibition, decreasing blood-brain barrier disruption and leukocyte infiltration.
Conclusions:
- Leukocytic miR-29b mitigates inflammatory responses by enhancing blood-brain barrier integrity.
- miR-29b represents a promising therapeutic target for ischemic stroke treatment.
