Monocyte Chemoattractant Protein 1, Macrophage Inflammatory Protein 1α, and RANTES Recruit Macrophages to the Kidney in a Mouse Model of Hemolytic-Uremic Syndrome

Abstract

The macrophage has previously been implicated in contributing to the renal inflammation associated with hemolytic-uremic syndrome (HUS). However, there is currently no in vivo model detailing the contribution of the renal macrophage to the kidney disease associated with HUS. Therefore, renal macrophage recruitment and inhibition of infiltrating renal macrophages were evaluated in an established HUS mouse model. Macrophage recruitment to the kidney was evident by immunohistochemistry 2 h after administration of purified Stx2 and peaked at 48 h postinjection. Mice administered a combination of Stx2 and lipopolysaccharide (LPS) showed increased macrophage recruitment to the kidney compared to mice treated with Stx2 or LPS alone. Monocyte chemoattractants were induced in the kidney, including monocyte chemoattractant protein 1 (MCP-1/CCL2), macrophage inflammatory protein 1␣ (MIP-1␣/CCL3), and RANTES (CCL5), in a pattern that was coincident with macrophage infiltration as indicated by immunohistochemistry, protein, and RNA analyses. MCP-1 was the most abundant chemokine, MIP-1␣ was the least abundant, and RANTES levels were intermediate. Mice treated with MCP-1, MIP-1␣, and RANTES neutralizing antibodies had a significant decrease in Stx2 plus LPS-induced macrophage accumulation in the kidney, indicating that these chemokines are required for macrophage recruitment. Furthermore, mice exposed to these three neutralizing antibodies had decreased fibrin deposition in their kidneys, implying that macrophages contribute to the renal damage associated with HUS.

Curcumin Attenuates Lipopolysaccharide-Induced Renal Inflammation

“…1A), indicating much more macrophage infiltration. The above distribution pattern of macrophage in mouse kidney after LPS injection was in agreement with the literature, 16) indicating the establishment of a renal inflammation model. Pretreatment with 5 mg/kg curcumin significantly decreased macrophage accumulation at both time points, as indicated by decreased area and deepness of the brown color in tissue sections (Fig.…”

“…These results imply that the enhancing effect of LPS on IL-8 and MCP-1 are mediated through a short term activation mechanism. Keepers et al 16) reported similar results where MCP-1 mRNA peaked even as early as at 2 h postinjection of LPS followed by a gradual decrease. However, the concentrations of IL-8 and MCP-1 in cell culture media responded to the LPS stimulation in a relatively slow manner.…”

“…These results were indeed reasonable as the main property of MCP-1 is the attraction of monocytes/ macrophage, 18) and it been reported to recruit macrophage in kidney diseases. 16,19) We further examined the effect of curcumin on kidney MCP-1 mRNA expression induced by LPS. Significant inhibition was observed even at 1 mg/kg curcumin, while LPS concentration used was as high as 5 mg/kg (Fig.…”

Lack of the Lectin-like Domain of Thrombomodulin Worsens Shiga Toxin-Associated Hemolytic Uremic Syndrome in Mice

“…Next, we investigated the expression of chemokines allowing neutrophil and macrophage recruitment in the Stx2/LPS model, specifically, MIP-2/CXCL2 and MCP-1/CCL2 (28,29). Chemokine mRNA was evaluated in renal tissue using quantitative realtime PCR.…”

“…Studies with blocking Abs or inactivation of the PECAM-1 gene indicate that the role of this protein in modulating leukocyte infiltration in inflamed tissues strongly depends on the stimulus and the experimental model used (26,27). There is evidence showing that in a mouse model of HUS (28,29), chemokines, including MIP-2 and MCP-1, are critical effectors of Stx-associated renal inflammation. In this study, we found that these chemokines were expressed at more extent in the kidneys of TM LeD/LeD than TM wt/wt mice after Stx2/LPS, indicating that they may contribute to the exuberant accumulation of PMNs and monocyte/macrophages in TM LeD/LeD mice.…”