C-reactive protein promotes acute kidney injury by impairing the G1/S-dependent tubular epithelial cell regeneration

C-reactive protein (CRP) is regarded as a inflammatory biomarker in acute kidney injury (AKI), but its exact role in AKI remains unclear. Thus, we sought to investigate the role of CRP in AKI. Clinically, elevated serum CRP were closely associated with an increased serum creatinine and urea (p<0.01) in patients with AKI, which was declined when AKI recovered. To determine the role of CRP in AKI, an ischemia-reperfusion mouse model of AKI was induced in transgenic (Tg) mice that express human CRP. Compared to wild type mice, CRP Tg mice developed more severe renal injury at 24h after ischemia determined by significantly increased serum creatinine and tubular necrosis. This was associated with impaired tubular epithelial cells (TEC) regeneration as evidenced by over 60% reduction in PCNA+ and BrdU+ TEC in CRP Tg mice with AKI. In vitro, addition of CRP to a human TEC line (HK-2) also largely suppressed the proliferation of TEC. The functional role of CRP in AKI was further demonstrated by the blocking CRP binding to its FcγRII with a neutralizing anti-CD32 antibody restoring the TEC proliferation and preventing AKI in CRP Tg mice. Moreover, we found that impaired G1/S transition by suppressing phosphorylation of CDK2 and expression of cyclin E may be a key mechanism by which CRP inhibited TEC regeneration during the AKI repair process. Conclusively, CRP plays a pathogenic role in AKI by inhibiting G1/S-dependent TEC regeneration. Results from this study ...
Source: Clinical Science - Category: Biomedical Science Authors: Source Type: research