Nanovesicles derived from bispecific CAR-T cells targeting the spike protein of SARS-CoV-2 for treating COVID-19.

BACKGROUND: Considering the threat of the COVID-19 pandemic, caused by SARS-CoV-2, there is an urgent need to develop effective treatments. At present, neutralizing antibodies and small-molecule drugs such as remdesivir, the most promising compound to treat this infection, have attracted considerable attention. However, some potential problems need to be concerned including viral resistance to antibody-mediated neutralization caused by selective pressure from a single antibody treatment, the unexpected antibody-dependent enhancement (ADE) effect, and the toxic effect of small-molecule drugs. RESULTS: Here, we constructed a type of programmed nanovesicle (NV) derived from bispecific CAR-T cells that express two single-chain fragment variables (scFv), named CR3022 and B38, to target SARS-CoV-2. Nanovesicles that express both CR3022 and B38 (CR3022/B38 NVs) have a stronger ability to neutralize Spike-pseudovirus infectivity than nanovesicles that express either CR3022 or B38 alone. Notably, the co-expression of CR3022 and B38, which target different epitopes of spike protein, could reduce the incidence of viral resistance. Moreover, the lack of Fc fragments on the surface of CR3022/B38 NVs could prevent ADE effects. Furthermore, the specific binding ability to SARS-CoV-2 spike protein and the drug loading capacity of CR3022/B38 NVs can facilitate targeted delivery of remdesiver to 293 T cells overexpressing spike protein. These results suggest that CR3022/B38 NVs have the potential ability to target antiviral drugs to the main site of viral infection, thereby enhancing the antiviral ability by inhibiting intracellular viral replication and reducing adverse drug reactions. CONCLUSIONS: In summary, we demonstrate that nanovesicles derived from CAR-T cells targeting the spike protein of SARS-COV-2 have the ability to neutralize Spike-pseudotyped virus and target antiviral drugs. This novel therapeutic approach may help to solve the dilemma faced by neutralizing antibodies and small-molecule drugs in the treatment of COVID-19.

Macrophage biomimetic nanocarriers for anti-inflammation and targeted antiviral treatment in COVID-19.

BACKGROUND: The worldwide pandemic of COVID-19 remains a serious public health menace as the lack of efficacious treatments. Cytokine storm syndrome (CSS) characterized with elevated inflammation and multi-organs failure is closely correlated with the bad outcome of COVID-19. Hence, inhibit the process of CSS by controlling excessive inflammation is considered one of the most promising ways for COVID-19 treatment. RESULTS: Here, we developed a biomimetic nanocarrier based drug delivery system against COVID-19 via anti-inflammation and antiviral treatment simultaneously. Firstly, lopinavir (LPV) as model antiviral drug was loaded in the polymeric nanoparticles (PLGA-LPV NPs). Afterwards, macrophage membranes were coated on the PLGA-LPV NPs to constitute drugs loaded macrophage biomimetic nanocarriers (PLGA-LPV@M). In the study, PLGA-LPV@M could neutralize multiple proinflammatory cytokines and effectively suppress the activation of macrophages and neutrophils. Furthermore, the formation of NETs induced by COVID-19 patients serum could be reduced by PLGA-LPV@M as well. In a mouse model of coronavirus infection, PLGA-LPV@M exhibited significant targeted ability to inflammation sites, and superior therapeutic efficacy in inflammation alleviation and tissues viral loads reduction. CONCLUSION: Collectively, such macrophage biomimetic nanocarriers based drug delivery system showed favorable anti-inflammation and targeted antiviral effects, which may possess a comprehensive therapeutic value in COVID-19 treatment.

Glycyrrhizic Acid Nanoparticles as Antiviral and Anti-inflammatory Agents for COVID-19 Treatment.

COVID-19 has been diffusely pandemic around the world, characterized by massive morbidity and mortality. One of the remarkable threats associated with mortality may be the uncontrolled inflammatory processes, which were induced by SARS-CoV-2 in infected patients. As there are no specific drugs, exploiting safe and effective treatment strategies is an instant requirement to dwindle viral damage and relieve extreme inflammation simultaneously. Here, highly biocompatible glycyrrhizic acid (GA) nanoparticles (GANPs) were synthesized based on GA. In vitro investigations revealed that GANPs inhibit the proliferation of the murine coronavirus MHV-A59 and reduce proinflammatory cytokine production caused by MHV-A59 or the N protein of SARS-CoV-2. In an MHV-A59-induced surrogate mouse model of COVID-19, GANPs specifically target areas with severe inflammation, such as the lungs, which appeared to improve the accumulation of GANPs and enhance the effectiveness of the treatment. Further, GANPs also exert antiviral and anti-inflammatory effects, relieving organ damage and conferring a significant survival advantage to infected mice. Such a novel therapeutic agent can be readily manufactured into feasible treatment for COVID-19.