Therapeutic Effects in a Transient Middle Cerebral Artery Occlusion Rat Model by Nose-To-Brain Delivery of Anti-TNF-Alpha siRNA with Cell-Penetrating Peptide-Modified Polymer Micelles.

Takanori Kanazawa,Yuuki Takashima,Takumi Kurano,Hisako Ibaraki,Yasuo Seta,Toyofumi Suzuki

doi:10.3390/pharmaceutics11090478

Takanori Kanazawa, Yuuki Takashima + Show 4 more

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https://doi.org/10.3390/pharmaceutics11090478

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Abstract

We previously reported that siRNA delivery to the brain is improved by the nose-to-brain delivery route and by conjugation with polyethylene glycol-polycaprolactone (PEG-PCL) polymer micelles and the cell-penetrating peptide, Tat (PEG-PCL-Tat). In this study, we evaluated the nose-to-brain delivery of siRNA targeting TNF-α (siTNF-α) conjugated with PEG-PCL-Tat to investigate its therapeutic effects on a transient middle cerebral artery occlusion (t-MCAO) rat model of cerebral ischemia-reperfusion injury. Intranasal treatment was provided 30 min after infarction induced via suturing. Two hours after infarction induction, the suture was removed, and blood flow was released. At 22 h post-reperfusion, we assessed the infarcted area, TNF-α production, and neurological score to determine the therapeutic effects. The infarcted area was observed over a wide range in the untreated group, whereas shrinkage of the infarcted area was observed in rats subjected to intranasal administration of siTNF-α with PEG-PCL-Tat micelles. Moreover, TNF-α production and neurological score in rats treated by intranasal administration of siTNF-α with PEG-PCL-Tat micelles were significantly lower than those in untreated and naked siTNF-α-treated rats. These results indicate that nose-to-brain delivery of siTNF-α conjugated with PEG-PCL-Tat micelles alleviated the symptoms of cerebral ischemia-reperfusion injury.

Highlights

Cerebral strokes are broadly classified either as cerebral infarctions, where the cerebral artery is constricted or obstructed causing necrosis in surrounding tissues, or as cerebral hemorrhages such as intracranial hemorrhages and subarachnoid hemorrhages [1,2]
After 48-h incubation, the cells were washed with PBS and transfected with naked Fluorescence 6-carboxyfluorescein-aminohexylphosphoramidite (FAM)-small interfering RNA (siRNA), FAM-siRNA/Lipotrust complex as a positive control or FAM-siRNA/MEG-PCL-Tat
The percentage of cells in the P2 region was used as an indicator of siRNA uptake into cells

Summary

Introduction

Cerebral strokes are broadly classified either as cerebral infarctions, where the cerebral artery is constricted or obstructed causing necrosis in surrounding tissues, or as cerebral hemorrhages such as intracranial hemorrhages and subarachnoid hemorrhages [1,2]. Conventional pharmacotherapies for ischemic brain injuries are broadly classified into four types: thrombolytic therapy, brain protection therapy, antiplatelet therapy, and anticoagulant therapy. Enlargement of the infarcted area and worsening of symptoms due to the post-ischemic inflammatory response have been focused upon [2,6]. Development of treatments that suppress post-ischemic inflammation and protect cranial nerves holds a lot of promise. The disruption of the blood–brain barrier (BBB) after stroke is associated with an inflammatory response and impaired cerebral autoregulation. Inflammation during ischemia occurs due to the production of inflammatory cytokines such as TNFα, IL-1β, and NF-κB from macrophages [9,10,11]

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