Indoxyl sulfate- and P-cresol-induced monocyte adhesion and migration is mediated by integrin-linked kinase-dependent podosome formation

Sofía Campillo,Mercedes Griera,Diego Rodríguez-Puyol,Sergio De Frutos,Elena Gutiérrez-Calabrés,Lourdes Bohorquez,Verónica Miguel,Diego García-Ayuso,Laura Calleros,Yolanda Calle,Manuel Rodríguez-Puyol

doi:10.1038/s12276-022-00738-8

Abstract

Cardiovascular disease is an important cause of death in patients with chronic kidney disease (CKD). Protein-bound uremic toxins, such as p-cresyl and indoxyl sulfate (IS), are poorly removed during hemodialysis, leading to vascular endothelial dysfunction and leukocyte extravasation. These processes can be related to dynamic adhesion structures called podosomes. Several studies have indicated the role of integrin-linked kinase (ILK) in the accumulation of integrin-associated proteins in podosomes. Here, we investigated the involvement of ILK and podosome formation in the adhesion and extravasation of monocytes under p-cresol (pc) and IS exposure. Incubation of THP-1 human monocyte cells with these toxins upregulated ILK kinase activity. Together, both toxins increased cell adhesion, podosome formation, extracellular matrix degradation, and migration of THP-1 cells, whereas ILK depletion with specific small interfering RNAs suppressed these processes. Interestingly, F-actin colocalized with cortactin in podosome cores, while ILK was colocalized in podosome rings under toxin stimulation. Podosome Wiskott-Aldrich syndrome protein (WASP)-interacting protein (WIP) and AKT protein depletion demonstrated that monocyte adhesion depends on podosome formation and that the ILK/AKT signaling pathway is involved in these processes. Ex vivo experiments showed that both toxins induced adhesion and podosome formation in leukocytes from wild-type mice, whereas these effects were not observed in leukocytes of conditional ILK-knockdown animals. In summary, under pc and IS stimulation, monocytes increase podosome formation and transmigratory capacity through an ILK/AKT signaling pathway-dependent mechanism, which could lead to vascular injury. Therefore, ILK could be a potential therapeutic target for the treatment of vascular damage associated with CKD.

Highlights

Chronic kidney disease (CKD) is a global health problem of substantial importance due to its high prevalence and its association with an increased risk for cardiovascular disease (CVD), a major cause of death in this population[1,2]
The present results strongly support the role of podosome formation in the transmigration potential of circulating monocytes exposed to several uremic toxins, such as those found in CKD
The integrin-linked kinase (ILK)/AKT pathway appears to be involved in podosome regulation under this condition, with subsequent effects on monocyte cell adhesion, migration, and matrix degradation capacity

Summary

Introduction

Chronic kidney disease (CKD) is a global health problem of substantial importance due to its high prevalence and its association with an increased risk for cardiovascular disease (CVD), a major cause of death in this population[1,2]. Dialyzed and nondialyzed patients with CKD have abnormally high proportions of intermediate (CD14++/CD16+) monocytes, which have important proinflammatory and atherogenic features[4,5] and are associated with atherosclerotic disease[6] and cardiovascular events[7]. In patients with advanced CKD, elevated serum concentrations of several circulating uremic toxins, notably indoxyl sulfate (IS) and p-cresyl sulfate (pCS), correlate with inflammatory markers[8]. A compelling body of evidence suggests that uremic toxins may predispose patients to CVD through increased monocyte adhesion, rolling, and extravasation.

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Results

Conclusion