RESUMEN
Radiation pneumonitis (RP) affects both patients and physicians during radiation therapy for lung cancer. To date, there are no effective drugs for improving the clinical outcomes of RP. The activation of angiotensin-converting enzyme 2 (ACE2) improves experimental acute lung injury caused by severe acute respiratory syndrome coronavirus, acid inhalation, and sepsis. However, the effects and underlying mechanisms of ACE2 in RP remain unclear. Therefore, this study aimed to investigate the effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers on RP and ACE2/angiotensin-(1-7)/Mas receptor pathway activation. We found that radiotherapy decreased the expression of ACE2 and that overexpression of ACE2 alleviated lung injury in an RP mouse model. Moreover, captopril and valsartan restored ACE2 activation; attenuated P38, ERK, and p65 phosphorylation; and effectively mitigated RP in the mouse model. Further systematic retrospective analysis illustrated that the incidence of RP in patients using renin-angiotensin system inhibitors (RASis) was lower than that in patients not using RASis (18.2% vs. 35.8% at 3 months, p = 0.0497). In conclusion, the current findings demonstrate that ACE2 plays a critical role in RP and suggest that RASis may be useful potential therapeutic drugs for RP.
Asunto(s)
Lesión Pulmonar Aguda , Neumonitis por Radiación , Animales , Ratones , FN-kappa B , Peptidil-Dipeptidasa A , Enzima Convertidora de Angiotensina 2 , Sistema Renina-Angiotensina , Estudios Retrospectivos , Antihipertensivos , Inhibidores EnzimáticosRESUMEN
The wide transmission and host adaptation of SARS-CoV-2 have led to the rapid accumulation of mutations, posing significant challenges to the effectiveness of vaccines and therapeutic antibodies. Although several neutralizing antibodies were authorized for emergency clinical use, convalescent patients derived natural antibodies are vulnerable to SARS-CoV-2 Spike mutation. Here, we describe the screen of a panel of SARS-CoV-2 receptor-binding domain (RBD) targeted nanobodies (Nbs) from a synthetic library and the design of a biparatopic Nb, named Nb1-Nb2, with tight affinity and super-wide neutralization breadth against multiple SARS-CoV-2 variants of concern. Deep-mutational scanning experiments identify the potential binding epitopes of the Nbs on the RBD and demonstrate that biparatopic Nb1-Nb2 has a strong escape-resistant feature against more than 60 tested RBD amino acid substitutions. Using pseudovirion-based and trans-complementation SARS-CoV-2 tools, we determine that the Nb1-Nb2 broadly neutralizes multiple SARS-CoV-2 variants at sub-nanomolar levels, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Delta (B.1.617.2), Lambda (C.37), Kappa (B.1.617.1), and Mu (B.1.621). Furthermore, a heavy-chain antibody is constructed by fusing the human IgG1 Fc to Nb1-Nb2 (designated as Nb1-Nb2-Fc) to improve its neutralization potency, yield, stability, and potential half-life extension. For the new Omicron variant (B.1.1.529) that harbors unprecedented multiple RBD mutations, Nb1-Nb2-Fc keeps a firm affinity (KD < 1.0 × 10-12 M) and strong neutralizing activity (IC50 = 1.46 nM for authentic Omicron virus). Together, we developed a tetravalent biparatopic human heavy-chain antibody with ultrapotent and broad-spectrum SARS-CoV-2 neutralization activity which highlights the potential clinical applications.
Asunto(s)
Anticuerpos Neutralizantes/farmacología , Anticuerpos Antivirales/farmacología , Fragmentos Fc de Inmunoglobulinas/farmacología , Proteínas Recombinantes de Fusión/farmacología , SARS-CoV-2/efectos de los fármacos , Anticuerpos de Dominio Único/farmacología , Anticuerpos Neutralizantes/biosíntesis , Anticuerpos Neutralizantes/genética , Anticuerpos Antivirales/biosíntesis , Anticuerpos Antivirales/genética , Afinidad de Anticuerpos , Ensayo de Inmunoadsorción Enzimática , Epítopos/química , Epítopos/inmunología , Escherichia coli/genética , Escherichia coli/metabolismo , Expresión Génica , Humanos , Fragmentos Fc de Inmunoglobulinas/biosíntesis , Fragmentos Fc de Inmunoglobulinas/genética , Modelos Moleculares , Pruebas de Neutralización , Unión Proteica/efectos de los fármacos , Conformación Proteica , Dominios y Motivos de Interacción de Proteínas , Proteínas Recombinantes de Fusión/biosíntesis , Proteínas Recombinantes de Fusión/genética , SARS-CoV-2/crecimiento & desarrollo , SARS-CoV-2/inmunología , Anticuerpos de Dominio Único/biosíntesis , Anticuerpos de Dominio Único/genética , Glicoproteína de la Espiga del Coronavirus/antagonistas & inhibidores , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/inmunologíaRESUMEN
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spreads worldwide and leads to an unprecedented medical burden and lives lost. Neutralizing antibodies provide efficient blockade for viral infection and are a promising category of biological therapies. Here, using SARS-CoV-2 spike receptor-binding domain (RBD) as a bait, we generate a panel of humanized single domain antibodies (sdAbs) from a synthetic library. These sdAbs reveal binding kinetics with the equilibrium dissociation constant (KD) of 0.99-35.5 nM. The monomeric sdAbs show half maximal neutralization concentration (EC50) of 0.0009-0.07 µg/mL and 0.13-0.51 µg/mL against SARS-CoV-2 pseudotypes, and authentic SARS-CoV-2, respectively. Competitive ligand-binding experiments suggest that the sdAbs either completely block or significantly inhibit the association between SARS-CoV-2 RBD and viral entry receptor ACE2. Fusion of the human IgG1 Fc to sdAbs improve their neutralization activity by up to ten times. These results support neutralizing sdAbs as a potential alternative for antiviral therapies.