C-C chemokine receptor 5 (CCR5) regulates leukocyte chemotaxis and activation, and its deficiency exacerbates development of nephritis. Therefore, we investigated the role of CCR5 during lipopolysaccharide (LPS)-induced acute kidney injury. CCR5-deficient (CCR5-/-) and wild-type (CCR5+/+) mice, both aged about 10 months, had acute renal injury induced by intraperitoneal injection of LPS (10 mg/kg). Compared with CCR5+/+ mice, CCR5-/- mice showed increased mortality and renal injury, including elevated creatinine and blood urea nitrogen levels, following LPS challenge. Compared to CCR5+/+ mice, CCR5-/- mice also exhibited greater increases in the serum concentrations of pro-inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β following LPS challenge. Furthermore, infiltration of macrophages and neutrophils, expression of intracellular adhesion molecule (ICAM)-1, and the number of apoptotic cells were more greatly increased by LPS treatment in CCR5-/- mice than in CCR5+/+ mice. The concentrations of pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β were also significantly increased in the kidney of CCR5-/- mice after LPS challenge. Moreover, primary kidney cells from CCR5-/- mice showed greater increases in TNF-α production and p38 MAP kinase activation following treatment with LPS compared with that observed in the cells from CCR5+/+ mice. LPS-induced TNF-α production and apoptosis in the primary kidney cells from CCR5-/- mice were inhibited by treatment with p38 MAP kinase inhibitor. These results suggest that CCR5 deficiency increased the production of TNF-α following LPS treatment through increased activation of the p38 pathway in the kidney, resulting in renal apoptosis and leukocyte infiltration and led to exacerbation of LPS-induced acute kidney injury.
Keywords: Acute kidney injury; CCR5; Cytokine; MAP kinase.