Caspases in COVID-19 disease and sequela and the therapeutic potential
of caspase inhibitors
Abstract
COVID-19 can present with lymphopenia and extraordinary complex
multi-organ pathologies that can trigger long-term sequela. Given that
inflammasome products, like caspase-1, play a role in the
pathophysiology of a number of co-morbid conditions, we investigated
caspases across the spectrum of COVID-19 disease. We assessed
transcriptional states of multiple caspases and using flow cytometry,
the expression of active caspase-1 in blood cells from COVID-19 patients
in acute and convalescent stages of disease. Non-COVID-19 subjects
presenting with various co-morbid conditions served as controls.
Single-cell RNA-seq data of immune cells from COVID-19 patients showed a
distinct caspase expression pattern in T cells, neutrophils, dendritic
cells and eosinophils compared to controls. Caspase-1 was upregulated in
CD4+ T-cells from hospitalized COVID-19 patients compared to unexposed
controls. Post-COVID-19 patients with lingering symptoms (long-haulers)
also showed up-regulated caspase-1 activity in CD4+ T-cells that ex vivo
was attenuated with a select pan-caspase inhibitor. We observed elevated
caspase-3/7 levels in red blood cells from COVID-19 patients compared to
controls that was reduced following caspase inhibition. Our preliminary
results suggest an exuberant caspase response in COVID-19 that may
facilitate immune-related pathological processes leading to severe
outcomes. Further clinical correlations of caspase expression in
different stages of COVID-19 will be needed. Pan-caspase inhibition
could emerge as a therapeutic strategy to ameliorate or prevent severe
COVID-19.