Browsing by Author "Luo, Xin"

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    BIOGENESIS OF NATIVE EXTRACELLULAR VESICLES AND GENERATION OF BIOENGINEERED EXTRACELLULAR VESICLES AS THERAPEUTIC AGENTS
    (2024-10-02) Luo, Xin; Kalluri, Raghu; Grande-Allen, Jane
    Extracellular vesicles (EVs) are small vesicles secreted from presumably all types of body cells naturally. EVs are involved in the bidirectional intercellular communication with functional impact. While the mechanism of EV generation and uptake by recipient cells is not fully understood, which is crucial for understanding their biological impact, EVs have already been considered as a drug delivery system in the context of various pathologies. To better evaluate mechanism involved in the biogenesis of EVs, I focused on the functional role of three EV-enriched tetraspanins, CD9, CD63, and CD8. Employing loss of function studies, the proteomics of cells deficient in CD9, CD63, or CD81, and EVs generated by these cells were functionally investigated. CD9, CD63, and CD81 were found to be important for sorting of specific proteins into the EVs, each one displayed distinct contribution in trafficking of proteins into EVs . Next, to explore how engineered EVs can be involved in the regulation of immunity, I designed an engineered EV-based platform for vaccine development (EVX-M+P) and for cancer immunotherapy (EVmIM). EVs were endogenously loaded with mRNA (M) and protein (P) encoding an antigen (X) for the design of EVX-M+P to induce rapid and robust adaptive immune response and protection from future exposure. As a proof of concept, spike protein of SARS-CoV-2 and human ovalbumin (OVA) were used successfully as antigens for vaccines against a viral disease and melanoma, respectively. Next, EVs were endogenously loaded to harbor multiple surface immunomodulatory proteins of CD80, 4-1BBL, CD40L, CD2, and CD32 to generate EVmIM, which could induce APCs and T cells activation simultaneously to strengthen the antigen presentation and immune response against cancer progression, validated in orthotopic melanoma mouse model. The simplicity of EVs modification and cargo loading, and successful testing of the EVX-M+P and EVmIM platforms, offer new methodologies that can streamline the development of a new class of vaccines and immunotherapies. Collectively, my thesis research opens novel vaccination and cancer immunotherapy strategies that can be developed for human testing.
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    Circulating ACE2-expressing extracellular vesicles block broad strains of SARS-CoV-2
    (Springer Nature, 2022) El-Shennawy, Lamiaa; Hoffmann, Andrew D.; Dashzeveg, Nurmaa Khund; McAndrews, Kathleen M.; Mehl, Paul J.; Cornish, Daphne; Yu, Zihao; Tokars, Valerie L.; Nicolaescu, Vlad; Tomatsidou, Anastasia; Mao, Chengsheng; Felicelli, Christopher J.; Tsai, Chia-Feng; Ostiguin, Carolina; Jia, Yuzhi; Li, Lin; Furlong, Kevin; Wysocki, Jan; Luo, Xin; Ruivo, Carolina F.; Batlle, Daniel; Hope, Thomas J.; Shen, Yang; Chae, Young Kwang; Zhang, Hui; LeBleu, Valerie S.; Shi, Tujin; Swaminathan, Suchitra; Luo, Yuan; Missiakas, Dominique; Randall, Glenn C.; Demonbreun, Alexis R.; Ison, Michael G.; Kalluri, Raghu; Fang, Deyu; Liu, Huiping; Bioengineering
    The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the pandemic of the coronavirus induced disease 2019 (COVID-19) with evolving variants of concern. It remains urgent to identify novel approaches against broad strains of SARS-CoV-2, which infect host cells via the entry receptor angiotensin-converting enzyme 2 (ACE2). Herein, we report an increase in circulating extracellular vesicles (EVs) that express ACE2 (evACE2) in plasma of COVID-19 patients, which levels are associated with severe pathogenesis. Importantly, evACE2 isolated from human plasma or cells neutralizes SARS-CoV-2 infection by competing with cellular ACE2. Compared to vesicle-free recombinant human ACE2 (rhACE2), evACE2 shows a 135-fold higher potency in blocking the binding of the viral spike protein RBD, and a 60- to 80-fold higher efficacy in preventing infections by both pseudotyped and authentic SARS-CoV-2. Consistently, evACE2 protects the hACE2 transgenic mice from SARS-CoV-2-induced lung injury and mortality. Furthermore, evACE2 inhibits the infection of SARS-CoV-2 variants (α, β, and δ) with equal or higher potency than for the wildtype strain, supporting a broad-spectrum antiviral mechanism of evACE2 for therapeutic development to block the infection of existing and future coronaviruses that use the ACE2 receptor.