Sharifpour Mohammad Farouq, Sikder Suchandan, Wong Yide, Koifman Na'ama, Thomas Tamara, Courtney Robert, Seymour Jamie, Loukas Alex
Australian Institute of Tropical Health and Medicine James Cook University Smithfield Queensland Australia.
Centre for Microscopy and Microanalysis The University of Queensland St Lucia Queensland Australia.
J Extracell Biol. 2024 Dec 12;3(12):e70025. doi: 10.1002/jex2.70025. eCollection 2024 Dec.
Spirulina is an edible cyanobacterium that increasingly gaining recognition for it untapped potential in the biomanufacturing of pharmaceuticals. Despite the rapidly accumulating information on extracellular vesicles (EVs) from most other bacteria, nothing is known about Spirulina extracellular vesicles (SPEVs). This study reports the successful isolation, characterization and visualization of SPEVs for the first time and it further investigates the potential therapeutic benefits of SPEVs using a mouse model. SPEVs were isolated using ultracentrifugation and size-exclusion-chromatography. Cryo-Transmission Electron Microscopy revealed pleomorphic outer-membrane-vesicles and outer-inner-membrane-vesicles displaying diverse shapes, sizes and corona densities. To assess short- and long-term immune responses, mice were injected intraperitoneally with SPEVs, which demonstrated a significant increase in neutrophils and M1 macrophages at the injection site, indicating a pro-inflammatory effect induced by SPEVs without clinical signs of toxicity or hypersensitivity. Furthermore, SPEVs demonstrated potent adjuvanticity by enhancing antigen-specific IgG responses in mice by over 100-fold compared to an unadjuvanted model vaccine antigen. Mass-spectrometry identified 54 proteins within SPEVs, including three protein superfamily members linked to the observed pro-inflammatory effects. Our findings highlight the potential of SPEVs as a new class of vaccine adjuvant and warrant additional studies to further characterize the nature of the immune response.
螺旋藻是一种可食用的蓝细菌，其在药物生物制造中尚未开发的潜力越来越受到认可。尽管关于大多数其他细菌的细胞外囊泡（EVs）的信息迅速积累，但对于螺旋藻细胞外囊泡（SPEVs）却一无所知。本研究首次报告了SPEVs的成功分离、表征和可视化，并进一步使用小鼠模型研究了SPEVs的潜在治疗益处。通过超速离心和尺寸排阻色谱法分离出SPEVs。冷冻透射电子显微镜显示多形性的外膜囊泡和外-内膜囊泡呈现出不同的形状、大小和晕密度。为了评估短期和长期免疫反应，给小鼠腹腔注射SPEVs，结果显示注射部位的中性粒细胞和M1巨噬细胞显著增加，表明SPEVs诱导了促炎作用，但没有毒性或超敏反应的临床迹象。此外，与无佐剂的模型疫苗抗原相比，SPEVs通过增强小鼠体内抗原特异性IgG反应，显示出强大的佐剂活性，增强了100倍以上。质谱分析确定了SPEVs中的54种蛋白质，包括与观察到的促炎作用相关的三个蛋白质超家族成员。我们的研究结果突出了SPEVs作为一类新型疫苗佐剂的潜力，并需要进一步研究以进一步表征免疫反应的性质。
