Effect of renin-angiotensin system activation on macrophage polarization. RAS activation triggers monocyte migration and activation. In the kidney, this process results in the accumulation of macrophages in the renal interstitium. AT1a receptor ligation on macrophages reduces expression of M1 phenotypic markers (MCP-1 (CCL-2), TNF-α, IL-1β), favoring expression of M2 phenotypic markers (Mannose receptor (CD206), TGF-beta, and IL-10). These alterations in gene expression have an anti-inflammatory effect and function to restrict damage to kidney tubules and interstitium instigated by RAS activation in the target organ