Angiopep-2 Modified Exosomes Load Rifampicin with Potential for Treating Central Nervous System Tuberculosis

Han Li,1,* Yinan Ding,2,* Jiayan Huang,1 Yanyan Zhao,1 Wei Chen,3 Qiusha Tang,2 Yanli An,4 Rong Chen,5 Chunmei Hu1 1Department of Tuberculosis, The Second Hospital of Nanjing, Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China; 2Medical School of Southeast University, Nanjing, People’s Republic of China; 3Department of Clinical Research Center, The Second Hospital of Nanjing, Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China; 4Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, People’s Republic of China; 5Department of Oncology, Zhongda Hospital, Southeast University, Nanjing, Jiangsu, People’s Republic of China*These authors contributed equally to this workCorrespondence: Chunmei Hu, Department of tuberculosis, the Second Hospital of Nanjing, Nanjing University of Chinese Medicine, Nanjing, 210009, People’s Republic of China, Email njyy003@njucm.edu.cnBackground: Central nervous system tuberculosis (CNS-TB) is the most devastating form of extrapulmonary tuberculosis. Rifampin (RIF) is a first-line antimicrobial agent with potent bactericidal action. Nonetheless, the blood-brain barrier (BBB) limits the therapeutic effects on CNS-TB. Exosomes, however, can facilitate drug movements across the BBB. In addition, exosomes show high biocompatibility and drug-loading capacity. They can also be modified to increase drug delivery efficacy. In this study, we loaded RIF into exosomes and modified the exosomes with a brain-targeting peptide to improve BBB permeability of RIF; we named these exosomes ANG-Exo-RIF.Methods: Exosomes were isolated from the culture medium of BMSCs by differential ultracentrifugation and loaded RIF by electroporation and modified ANG by chemical reaction. To characterize ANG-Exo-RIF, Western blot (WB), nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM) were performed. Bend.3 cells were incubated with DiI labeled ANG-Exo-RIF and then fluorescent microscopy and flow cytometry were used to evaluate the targeting ability of ANG-Exo-RIF in vitro. Fluorescence imaging and frozen section were used to evaluate the targeting ability of ANG-Exo-RIF in vivo. MIC and MBC were determined through microplate alamar blue assay (MABA).Results: A novel exosome-based nanoparticle was developed. Compared with untargeted exosomes, the targeted exosomes exhibited high targeting capacity and permeability in vitro and in vivo. The MIC and MBC of ANG-Exo-RIF were 0.25 μg/mL, which were sufficient to meet the clinical needs.Conclusion: In summary, excellent targeting ability, high antitubercular activity and biocompatibility endow ANG-Exo-RIF with potential for use in future translation-aimed research and provide hope for an effective CNS-TB treatment.Graphical Abstract: Keywords: exosome, central nervous system tuberculosis, blood-brain barrier, rifampin