NFκB and NLRP3/NLRC4 inflammasomes regulate differentiation, activation and functional properties of monocytes in response to distinct SARS-CoV-2 proteins

Abstract

Inflammasomes; Monocytes; SARS-CoV-2

Inflammasomes; Monòcits; SARS-CoV-2

Inflamasomas; Monocitos; SARS-CoV-2

Increased recruitment of transitional and non-classical monocytes in the lung during SARS-CoV-2 infection is associated with COVID-19 severity. However, whether specific innate sensors mediate the activation or differentiation of monocytes in response to different SARS-CoV-2 proteins remain poorly characterized. Here, we show that SARS-CoV-2 Spike 1 but not nucleoprotein induce differentiation of monocytes into transitional or non-classical subsets from both peripheral blood and COVID-19 bronchoalveolar lavage samples in a NFκB-dependent manner, but this process does not require inflammasome activation. However, NLRP3 and NLRC4 differentially regulated CD86 expression in monocytes in response to Spike 1 and Nucleoprotein, respectively. Moreover, monocytes exposed to Spike 1 induce significantly higher proportions of Th1 and Th17 CD4 + T cells. In contrast, monocytes exposed to Nucleoprotein reduce the degranulation of CD8 + T cells from severe COVID-19 patients. Our study provides insights in the differential impact of innate sensors in regulating monocytes in response to different SARS-CoV-2 proteins, which might be useful to better understand COVID-19 immunopathology and identify therapeutic targets.

I.T. was supported by Fomento de Investigación and FPI-UAM fellowships by Universidad Autónoma de Madrid. E.M.G. and I.T. were funded by PID2021-127899OB-I00 Generación de Conocimiento and CNS2023-144841 consolidación investigadora grants from Agencia Estatal de Investigación. E.M.G. and C.D.A. were also supported by RYC2018-024374-I. Ramón y Cajal Program. E.M.G., M.J.B., and M.G. were supported by REDINCOV by la MARATÓ TV3 (202104-30-31) and La Caixa Foundation HR20-00218. E.M.G., I.S. and I.S.C. were funded by CIBERINFECC from Instituto de Salud Carlos III. O.P. was supported by REDINCOV. MCM was supported by La Caixa Banking Foundation LCF/PR/HR20-00218. IGA was supported by PEARL thanks to grants RD16/0011/0012 and PI18/0371 from the Ministerio de Economía y Competitividad (Instituto de Salud Carlos III) and co-funded by Fondo Europeo de Desarrollo Regional (FEDER). I.S.C. was supported by the Rio Hortega Grant program (CM21/00157) and CIBERINFECC from Instituto de Salud Carlos III. F.S.M., A.A. were supported by INMUNOVACTER REACT-EU grant from Comunidad de Madrid. F.S.M. was also supported by grants PDC2021-121719-I00 and PID-2020-120412RB-I00 from the Spanish Ministry of Economy and Competitiveness (MINECO). M.J.B. is supported by the Agencia Estatal de Investigación project PID2021-123321OB-I00 funded by MCIN /AEI /10.13039/501100011033/ FEDER, UE; the Gilead Fellowship GLD22/00152, and the Miguel Servet program funded by the Spanish Health Institute Carlos III (CPII22/00005). N.M.C. was supported by S2022/BMD-7209 (INTEGRAMUNE-CM) to N.M.C. C.M.C. was supported by FIS.18/01163. F.S.M. and N.M.C. were also supported by La Caixa Health Research Grant LCF/PR/HR23/52430018. Grants to A.A. from the Fondo de Investigación Sanitaria del Instituto de Salud Carlos III, co-funded by the Fondo Europeo de Desarrollo Regional (FEDER) (FIS PI19/00549; FIS PI22/01542), and Sociedad Cooperativa de Viviendas Buen Suceso, S. Coop. Mad; to A.A. and F.S.M. from the Fondo de Investigación Sanitaria del Instituto de Salud Carlos III, co-funded by the Fondo Europeo de Desarrollo Regional (FEDER) (CIBER Cardiovascular). A.A. was supported by CIBER cardiovascular (CIBERCV) from Instituto de Salud Carlos III. L.E.P. was financed by Inmunovacter REACT-UE (Comunidad de Madrid). We also would like to thank Verónica Labrador from the Microscopy Core from Centro Nacional de Investigaciones Cardiovasculares for technical support in confocal image analysis.