Exosomes from COVID-19 patients carry tenascin-C and fibrinogen-β in triggering inflammatory signals in distant organ cells

SARS-CoV-2 infection causes cytokine storm and overshoot immunity in humans; however, it remains to be determined whether genetic material of SARS-CoV-2 and/or virus induced soluble mediators from lung epithelial cells as natural host are carried out by macrophages or other vehicles at distant organs causing tissue damage. We speculated that exosomes as extracellular vesicles are secreted from SARS-CoV-2 infected cells may transport messages to other cells of distant organs leading to pathogenic consequences. For this, we took an unbiased proteomic approach for analyses of exosomes isolated from plasma of healthy volunteers and SARS-CoV-2 infected patients. Our results revealed that tenascin-C (TNC) and fibrinogen-{beta} (FGB) are highly abundant in exosomes from SARS-CoV-2 infected patients plasma as compared to that of healthy normal controls. Since TNC and FGB stimulate pro-inflammatory cytokines via NF-{kappa}B pathway, we examined the status of TNF-, IL-6 and CCL5 expression upon exposure of hepatocytes to exosomes from COVID-19 patients and observed significant increase when compared with that from healthy subjects. Together, our results demonstrated that soluble mediators, like TNC and FGB, are transported through plasma exosomes in SARS-CoV-2 infected patients and trigger pro-inflammatory cytokine expression in cells of distant organs in COVID-19 patients. ImportanceExosomes play an important role in intercellular communication by inducing physiological changes in recipient cells by transferring bioactive proteins. Little is known about exosomes from SARS-CoV-2 infected cells and their role in pathogenesis. Here, we have carefully examined and analyzed this aspect of SARS-CoV-2 infection. Our results uncovered the potential mechanisms by which SARS-CoV-2 communicates with other cells of distant organs and promotes pathogenesis. We expect to detect whether other factors are modulated in the presence of COVID-19 exosomes. Our exosomes related proteomic experiments prioritize after initial verification to further examine their role in SARS-CoV-2 associated other pathogenic mechanisms to target for therapeutic modalities.