AIM: Failure of transplanted cartilage or allogenic chondrocytes is attributed mainly to immunological rejection and cartilage degradation. A major feature is the loss of aggrecan from the cartilage matrix, primarily due to the action of the specific proteinases aggrecanase-1 and aggrecanase-2. The aim of this in vitro study was to determine whether the specific inhibition of aggrecanase-1 and aggrecanase-2 by RNAi would mitigate aggrecan loss from cultured chondrocytes. METHODS: Expression plasmid vectors of shRNA targeting aggrecanase-1 and aggrecanase-2 were constructed and transfected into cultured rattus costochondral chondrocytes. The transfected cells were induced with interleukin-1beta (IL-1beta). Gene mRNA levels were analyzed by RT-PCR. Aggrecan and collagen II content were measured by immunohistochemistry and Western blotting. RESULTS: As the chondrocytes underwent dedifferentiation, aggrecanase-1 increased significantly. The specific inhibition of aggrecanase-1 and aggrecanase-2 by RNAi had no negative effect on the morphology and growth velocity of the chondrocytes. The mRNA of aggrecanase-1 and aggrecanase-2 decreased significantly. The alpha-2-macroglobulin expression level was increased by the shRNA specific for aggrecanase-1. Other genes of the chondrocytic extracellular matrix were not affected. RNAi significantly increased the aggrecan and collagen II content of chondrocytes treated with IL-1beta. CONCLUSION: The results suggest that inhibition of aggrecanase-1 and aggrecanase-2 by RNAi can mitigate aggrecan degradation, without interfering with chondrocytic gene phenotype recovery. RNAi technology can be a useful tool for studying degenerative processes in cartilage.
AIM: Failure of transplanted cartilage or allogenic chondrocytes is attributed mainly to immunological rejection and cartilage degradation. A major feature is the loss of aggrecan from the cartilage matrix, primarily due to the action of the specific proteinases aggrecanase-1 and aggrecanase-2. The aim of this in vitro study was to determine whether the specific inhibition of aggrecanase-1 and aggrecanase-2 by RNAi would mitigate aggrecan loss from cultured chondrocytes. METHODS: Expression plasmid vectors of shRNA targeting aggrecanase-1 and aggrecanase-2 were constructed and transfected into cultured rattus costochondral chondrocytes. The transfected cells were induced with interleukin-1beta (IL-1beta). Gene mRNA levels were analyzed by RT-PCR. Aggrecan and collagen II content were measured by immunohistochemistry and Western blotting. RESULTS: As the chondrocytes underwent dedifferentiation, aggrecanase-1 increased significantly. The specific inhibition of aggrecanase-1 and aggrecanase-2 by RNAi had no negative effect on the morphology and growth velocity of the chondrocytes. The mRNA of aggrecanase-1 and aggrecanase-2 decreased significantly. The alpha-2-macroglobulin expression level was increased by the shRNA specific for aggrecanase-1. Other genes of the chondrocytic extracellular matrix were not affected. RNAi significantly increased the aggrecan and collagen II content of chondrocytes treated with IL-1beta. CONCLUSION: The results suggest that inhibition of aggrecanase-1 and aggrecanase-2 by RNAi can mitigate aggrecan degradation, without interfering with chondrocytic gene phenotype recovery. RNAi technology can be a useful tool for studying degenerative processes in cartilage.
Authors: Z H Wang; X L Li; X J He; B J Wu; M Xu; H M Chang; X H Zhang; Z Xing; X H Jing; D M Kong; X H Kou; Y Y Yang Journal: Braz J Med Biol Res Date: 2014-03-18 Impact factor: 2.590