Conceptual model for NAb mRNA and PAC-MAN in-vivo delivery through rSARS-CoV-2 vector via ACE-2 receptors binding mechanism: Deep amalgamation approach to COVID-19 vaccine

The paper presents a conceptual model for the development of recombinant SARS-CoV-2 as a vector for in-vivo delivery of viral neutralizing antibodies gene and PAC-MAN into human respiratory epithelial cells. The theoretical proposal suggests the sequence length, potential antibody candidates (as reported in the recent literature) and brief protocol which can be applied to produce rSARS-CoV-2 in the laboratory to test its effectiveness against most of the SARS-CoV-2 strains. Finally, a method for release of such functional vector is been discussed.

Effect of β-chitosan on the binding interaction between SARS-CoV-2 S-RBD and ACE2

ABSTRACTSARS-CoV-2 invades human respiratory epithelial cells via an interaction between its spike RBD protein (SARS-CoV-2 S-RBD) and the host cell receptor angiotensin converting enzyme II (ACE2). Blocking this interaction provides a potent approach to preventing and controlling SARS-CoV-2 infection. In this work, the ability of β-chitosan to block the binding interaction between SARS-CoV-2 S-RBD and ACE2 was investigated. The inhibitory effect of β-chitosan on inflammation induced by the SARS-CoV-2 S-RBD was also studied. Native-PAGE analysis indicated that β-chitosan could bind with ACE2 and the SARS-CoV-2 S-RBD and a conjugate of β-chitosan and ACE2 could no longer bind with the SARS-CoV-2 S-RBD. HPLC analysis suggested that a conjugate of β-chitosan and the SARS-CoV-2 S-RBD displayed high binding affinity without dissociation under high pressure (40 MPa) compared with that of β-chitosan and ACE2. Furthermore, immunofluorescent staining of Vero E6 cells and lungs from hACE2 mice showed that the presence of β-chitosan prevented SARS-CoV-2 S-RBD from binding to ACE2. Meanwhile, β-chitosan could dramatically suppress the inflammation caused by the presence of the SARS-CoV-2 S-RBD both in vitro and vivo. Moreover, the decreased expression of ACE2 caused by β-chitosan treatment was restored by addition of TAPI-1, an inhibitor of the transmembrane protease ADAM17. Our findings demonstrated that β-chitosan displays an antibody-like function capable of neutralizing the SARS-CoV-2 S-RBD and effectively preventing the binding of the SARS-CoV-2 S-RBD to ACE2. Moreover, ADAM17 activation induced by β-chitosan treatment can enhance the cleavage of the extracellular domain of ACE2, releasing the active ectodomain into the extracellular environment, which can prevent the binding, internalization, and degradation of ACE2 bound to the SARS-CoV-2 S-RBD and thus diminish inflammation. Our study provides an alternative avenue for preventing SARS-CoV-2 infection using β-chitosan.

Effect of calcium on the interaction of Acinetobacter baumannii with human respiratory epithelial cells

Background Investigating the factors that influence Acinetobacter baumannii(Ab) adhesion/invasion of host cells is important to understand its pathogenicity. Metal cations have been shown to play an important role in regulating the biofilm formation and increasing the virulence of Ab; however, the effect of calcium on host-bacterial interaction has yet to be clarified. Here, the dynamic process of the interaction between Ab and human respiratory epithelial cells and the effect of calcium on host-bacterial interaction were explored using microscopic imaging, quantitative PCR and real time cellular analysis (RTCA). Results The concentration of calcium, multiplicity of infection and co-culture time were all demonstrated to have effects on host-bacterial interaction. A unique “double peak” phenomenon changed to a sharp “single peak” phenomenon during the process of Ab infection under the effect of calcium was observed in the time-dependent cell response profiles. Moreover, calcium can increase Ab adhesion/invasion of epithelial cells by regulating the expression of Ab-related genes (ompA, bfmRS, abaI). Conclusions Effective control of calcium concentrations can provide new approaches for the prevention and treatment of multi-drug resistant Ab.

Effect of Calcium on the Interaction of Acinetobacter baumannii with Human Respiratory Epithelial Cells

Background: Investigating the factors that influence Acinetobacter baumannii(Ab) adhesion/invasion of host cells is important to understand its pathogenicity. Metal cations have been shown to play an important role in regulating the biofilm formation and increasing the virulence of Ab; however, the effect of calcium on host-bacterial interaction has yet to be clarified. Here, the dynamic process of the interaction between Ab and human respiratory epithelial cells and the effect of calcium on host-bacterial interaction were explored using microscopic imaging, quantitative PCR and real time cellular analysis (RTCA). Results: The concentration of calcium, multiplicity of infection and co-culture time were all demonstrated to have effects on host-bacterial interaction. A unique "double peak" phenomenon changed to a sharp "single peak" phenomenon during the process of Ab infection under the effect of calcium was observed in the time-dependent cell response profiles. Moreover, calcium can increase Ab adhesion/invasion of epithelial cells by regulating the expression of Ab-related genes (ompA, bfmRS, abaI). Conclusions: Effective control of calcium concentrations can provide new approaches for the prevention and treatment of multi-drug resistant Ab.

Effect of Calcium on the Interaction of Acinetobacter baumannii with Human Respiratory Epithelial Cells

Background: Investigating the factors that influence Acinetobacter baumannii (Ab) adhesion/invasion of host cells is important to understand its pathogenicity. Metal cations have been shown to play an important role in regulating the biofilm formation and increasing the virulence of Ab; however, the effect of calcium on host-bacterial interaction has yet to be clarified. Here, the dynamic process of the interaction between Ab and human respiratory epithelial cells and the effect of calcium on host-bacterial interaction were explored using the technologies of microscopic imaging, quantitative PCR and real time cellular analysis (RTCA). Results: The concentration of calcium, multiplicity of infection and co-culture time were demonstrated to have effects on host-bacterial interaction. A unique "double peak" phenomenon changed to a sharp "single peak" phenomenon during the process of Ab infection under the effect of calcium were determined based on the time-dependent cell response profiles. Moreover, calcium can increase Ab adhesion/invasion of epithelial cells by regulating the expression of Ab-related genes ( ompA , bfmRS , abaI ). Conclusions: Effective control of calcium concentrations can provide new ideas for the prevention and treatment of multi-drug resistant Ab.