First published November 3, 2008 - More info
Aggrecan loss from cartilage in arthritis is mediated by aggrecanases. Aggrecanases cleave aggrecan preferentially in the chondroitin sulfate–2 (CS-2) domain and secondarily at the E373↓374A bond in the interglobular domain (IGD). However, IGD cleavage may be more deleterious for cartilage biomechanics because it releases the entire CS-containing portion of aggrecan. Recent studies identifying aggrecanase-2 (ADAMTS-5) as the predominant aggrecanase in mouse cartilage have not distinguished aggrecanolysis in the IGD from aggrecanolysis in the CS-2 domain. We generated aggrecan knockin mice with a mutation that rendered only the IGD resistant to aggrecanases in order to assess the contribution of this specific cleavage to cartilage pathology. The knockin mice were viable and fertile. Aggrecanase cleavage in the aggrecan IGD was not detected in knockin mouse cartilage in situ nor following digestion with ADAMTS-5 or treatment of cartilage explant cultures with IL-1α. Blocking cleavage in the IGD not only diminished aggrecan loss and cartilage erosion in surgically induced osteoarthritis and a model of inflammatory arthritis, but appeared to stimulate cartilage repair following acute inflammation. We conclude that blocking aggrecanolysis in the aggrecan IGD alone protects against cartilage erosion and may potentiate cartilage repair.
Christopher B. Little, Clare T. Meeker, Suzanne B. Golub, Kate E. Lawlor, Pamela J. Farmer, Susan M. Smith, Amanda J. Fosang
Original citation: J. Clin. Invest.117:1627–1636 (2007). doi:10.1172/JCI30765.
Citation for this corrigendum: J. Clin. Invest.118:3812 (2008). doi:10.1172/JCI30765C1.
The formula used to calculate cartilage repair is described incorrectly on page 1635. The correct description of the formula appears below.
The cartilage repair score at day 28 was calculated by subtracting the number from 1. Positive scores indicate percentage of improvement, and negative scores indicate the percentage by which the score worsened, compared with day 7.
The authors regret the error.