Department of Systems Biology, Physiology Unit, Universidad de Alcalá, Alcalá de Henares, Spain.
Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Fundación Renal Iñigo Álvarez de Toledo (FRIAT) and REDinREN, (ISCIII), Madrid, Spain.
Exp Mol Med. 2022 Mar;54(3):226-238. doi: 10.1038/s12276-022-00738-8. Epub 2022 Mar 4.
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.
心血管疾病是慢性肾脏病(CKD)患者的重要死亡原因。蛋白结合型尿毒症毒素,如对甲酚(p-cresyl)和吲哚硫酸酯(IS),在血液透析过程中去除效果不佳,导致血管内皮功能障碍和白细胞渗出。这些过程可能与称为足突的动态黏附结构有关。几项研究表明整合素连接激酶(ILK)在足突中整合素相关蛋白的积累中起作用。在这里,我们研究了在 p-甲酚(pc)和 IS 暴露下,ILK 和足突形成在单核细胞黏附和渗出中的作用。用这些毒素孵育 THP-1 人单核细胞会增加 ILK 激酶活性。这两种毒素共同增加了 THP-1 细胞的黏附、足突形成、细胞外基质降解和迁移,而特异性小干扰 RNA 耗尽 ILK 则抑制了这些过程。有趣的是,F-肌动蛋白与足突核心中的桩蛋白共定位,而在毒素刺激下,ILK 与足突环共定位。足突 Wiskott-Aldrich 综合征蛋白(WASP)相互作用蛋白(WIP)和 AKT 蛋白耗竭表明单核细胞黏附依赖于足突形成,并且 ILK/AKT 信号通路参与了这些过程。离体实验表明,这两种毒素均可诱导野生型小鼠白细胞黏附和足突形成,但在条件性 ILK 敲低动物的白细胞中未观察到这些作用。总之,在 pc 和 IS 刺激下,单核细胞通过依赖于 ILK/AKT 信号通路的机制增加足突形成和迁移能力,这可能导致血管损伤。因此,ILK 可能是治疗与 CKD 相关血管损伤的潜在治疗靶点。