The NF- κ B1 is a key regulator of acute but not chronic renal injury

The NF- κ B family of transcription factors is important for many cellular functions, in particular initiation and propagation of inflammatory and immune responses. However, recent data has suggested that different subunits of the NF- κ B family can suppress the inflammatory response. NF- κ B1, from the locus nfκb1, can inhibit transcription, acting as a brake to the recognised pro-inflammatory activity of other NF- κ B subunits. We tested the function of NF- κ B1 in an acute (nephrotoxic serum (NTS) nephritis) and a chronic (unilateral ureteric obstruction (UUO)) model of renal injury using NF- κ B1 ( nfκb1 −/− ) knockout mice. Deficiency in NF- κ B1 increased the severity of glomerular injury in NTS-induced nephritis and was associated with greater proteinuria and persistent pro-inflammatory gene expression. Induction of disease in bone marrow chimeric mice demonstrated that the absence of NF- κ B1 in either bone marrow or glomerular cells increased the severity of injury. Early after UUO (day 3) there was more severe histological injury in the nfκb1 −/− mice but by day 10, disease severity was equivalent in wild type and nfκb1 −/− mice. In conclusion, NF- κ B1 modifies acute inflammatory renal injury but does not influence chronic fibrotic injury.