Activation of Wnt/β-catenin pathway in monocytes derived from chronic kidney disease patients

Abstract

Patients with chronic kidney disease (CKD) have significantly increased morbidity and mortality resulting from infections and cardiovascular diseases. Since monocytes play an essential role in host immunity, this study was directed to explore the gene expression profile in order to identify differences in activated pathways in monocytes relevant to the pathophysiology of atherosclerosis and increased susceptibility to infections. Monocytes from CKD patients (stages 4 and 5, estimated GFR <20 ml/min/1.73 m(2)) and healthy donors were collected from peripheral blood. Microarray gene expression profile was performed and data were interpreted by GeneSpring software and by PANTHER tool. Western blot was done to validate the pathway members. The results demonstrated that 600 and 272 genes were differentially up- and down regulated respectively in the patient group. Pathways involved in the inflammatory response were highly expressed and the Wnt/β-catenin signaling pathway was the most significant pathway expressed in the patient group. Since this pathway has been attributed to a variety of inflammatory manifestations, the current findings may contribute to dysfunctional monocytes in CKD patients. Strategies to interfere with this pathway may improve host immunity and prevent cardiovascular complications in CKD patients.

Figure 1. Gene expression pattern in peripheral monocytes from three healthy subjects (H4, H5, H6) and three patients with CKD stages 4 and 5 (eGFR <20 ml/min/1.73 m²) (P1, P2, P3).

The gene expression intensity is presented in red (high expression intensity) and blue (low expression intensity).

Figure 2. Schematic view for Wnt/β-catenin signaling shows the expression of genes and proteins involved in Wnt/β-catenin signaling in both CKD patients (P) and healthy subjects (H).

Figure 3. Western blot of CK1ε, DVL1, PGSKβ, GSKβ, β-catenin, and Tubulin from ten healthy subjects (H) and fourteen CKD patients (P).

The sample name which is in bold corresponds to the sample used in microarray.

Figure 4. Densitometry of Western blot from fourteen patients and ten healthy Tubulin was used to normalize the results of β-catenin, DVL1 and CK1ε while GSKβ were used to normalize PGSKβ A) PGSK (P<0.01), B) CK1ε (P<0.0001), C) DVL1 (P<0.00001) and D) β-catenin (P<0.05d).