Cerebrovascular damage caused by the gut microbe-derived uraemic toxin p-cresol sulfate isprevented by blockade of the epidermal growth factor receptor

Abstract

Circulating levels of the gut microbe/host co-metabolite p-cresol sulfate (pCS) correlate with cerebrovascular event risk in individuals with chronic kidney disease, but whether this relationship is mechanistic is unclear. We hypothesised that pCS would impair function of the blood-brain barrier (BBB), the primary brain-vasculature interface. We report that pCS exposure impairs BBB integrity in human cells in vitro and both acutely and chronically in mice, enhancing tracer extravasation, disrupting barrier-regulating tight junction components and ultimately affecting whole-brain transcriptomic activity. In vitro and in vivo mechanistic studies showed that pCS activated epidermal growth factor receptor (EGFR) signalling, resulting in matrix metalloproteinase mobilisation and BBB damage. Furthermore, blockade of EGFR prevented the permeabilising effects of serum from haemodialysis patients upon cerebromicrovascular endothelia in vitro. Our results define a pathway linking the co- metabolite pCS with BBB damage and suggest targeting the EGFR may mitigate against cerebrovascular damage in CKD.