2026-09-14 カロリンスカ研究所（KI）
＜関連情報＞
- https://news.ki.se/new-method-tested-against-bacterial-toxin-in-the-brain
- https://isevjournals.onlinelibrary.wiley.com/doi/10.1002/jev2.70369
バイオエンジニアリングされた細胞外小胞は、実験的肺炎球菌性髄膜炎において、ニューモリシンを中和し、疾患の発症を遅らせることにより、神経炎症を軽減する Bioengineered Extracellular Vesicles Mitigate Neuroinflammation by Neutralizing Pneumolysin and Delaying Disease Onset in Experimental Pneumococcal Meningitis
Kristine Farmen, Doste R. Mamand, Miguel Tofiño-Vian, Georgia Yfanti, Xiuming Liang, Houze Zhou, Vicky W. Q. Hou, Samir El Andaloussi, Oscar P. B. Wiklander, Federico Iovino
Journal of Extracellular Vesicles Published: 11 September 2026
DOI:https://doi.org/10.1002/jev2.70369
ABSTRACT
Bacterial meningitis is a life-threatening neurological disorder frequently caused by a Streptococcus pneumoniae (the pneumococcus) infection of the brain. Standard treatment consists of antibiotics to eliminate bacteria and dexamethasone to reduce inflammation. Despite this, mortality reaches 20% in treated individuals, and half of the survivors suffer long-term neurological sequelae. This is largely due to the poor capacity of antibiotics to reach the brain and the lack of antimicrobial treatment capable of neutralizing the pneumococcal toxin pneumolysin (Ply). To address these limitations, we isolated extracellular vesicles (EVs) derived from human HEK293T cells and evaluated their therapeutic potential in pneumococcal meningitis. Alongside wild-type EVs (WT.EVs), we bioengineered EVs to express RVG peptides (RVG.EV) for targeting neuronal acetylcholine receptors, signal incompetent IL-6 signal transducer (IL-6ST) decoy receptors (IL-6.EV) to block the pro-inflammatory signalling of IL-6, or EVs expressing both RVG peptides and IL-6ST (DB.EV). In vitro, all EVs reduced pneumococcal adhesion to neurons and mitigated cytotoxicity by binding and sequestering Ply. In a bacteremia-derived pneumococcal meningitis model, EV treatment significantly increased the survival of the mice without affecting bacterial load in the brain or the periphery. Among all groups, RVG.EV treatment was most effective in reducing pro-inflammatory cytokine release in the periphery and brain. These findings highlight the therapeutic potential of bioengineered EVs, particularly RVG peptides expressing EVs, as an adjunctive treatment for pneumococcal meningitis thanks to their (i) sequestration and neutralization of Ply, (ii) increased blood-brain barrier crossing, and (iii) dampening of inflammation.
