SARS-CoV-2 nucleocapsid protein induces a Mincle-dependent macrophage inflammatory response in acute kidney injury.

Background: Although the COVID-19 pandemic has receded, the SARS-CoV-2 virus still poses a significant threat to individuals with pre-existing renal conditions, leading to severe acute kidney injury (AKI). However, the underlying mechanisms remain poorly understood.

Methods: In this study, we used ultrasound microbubble technology to transfect and overexpress the SARS-CoV-2 nucleocapsid (N) protein in the kidneys of IRI (ischemia-reperfusion injury) and Cis (cisplatin) induced AKI mice. Additionally, we generated macrophage-specific Mincle knockout mice to investigate the amplifying effects of the SARS-CoV-2 N protein on AKI renal injury and the critical regulatory role of macrophage inducible C-type lectin (Mincle). Finally, we employed Mincle-neutralizing antibodies to intervene in the SARS-CoV-2 N-induced exacerbation of kidney injury in AKI.

Results: We found that the specific overexpression of the SARS-CoV-2 N protein significantly aggravates kidney injury in the context of AKI. Mechanistically, we found that the exacerbation of acute kidney injury by the SARS-CoV-2 N protein is dependent on Mincle, as the SARS-CoV-2 N protein activates Mincle to enhance the Syk/NF-κB signaling pathway, leading to damage and inflammation of renal tubular epithelial cells. This was confirmed in Mincle knockout mice and cells, where Mincle knockout alleviated the renal tubular injury and inflammation caused by SARS-CoV-2 N transfection. Importantly, the use of anti-Mincle neutralizing antibodies could effectively mitigate the acute kidney injury exacerbated by the SARS-CoV-2 N protein.

Conclusions: In summary, we identified the SARS-CoV-2 N protein as a key mediator of kidney injury in AKI and demonstrated that it exacerbates the injury through a Mincle-dependent mechanism. Targeting Mincle may represent a novel therapeutic strategy for treating COVID-19-related acute kidney injury.