Chondroprotective strategy delivers antisense sequence to cells by virus

MIAMI — An antisense sequence that hones in on TS-5 mRNA and is delivered to articular chondrocytes using an adeno-associated virus may have chondroprotective effects, according to the results of an award-winning basic science study presented here.

Hannah H. Lee and her colleagues transfected the articular chondrocytes of rats with a plasmid encoding ADAMTS-5 (a disintegrin and metalloproteinase with thrombospondin repeats-5) antisense sequence. The chondrocytes were then stimulated with Interleukin 1-beta (IL-1ß) for 24 hours, and the investigators measured the TS-5 expression.

The investigators harvested the femoral explants and placed them into the following groups to assess transduction with adeno-associated virus encoding luciferase (AAV-luc):

a non-AAV control group;
an AAV-luc group; and,
a mechanical injury group that had a scratched condyle prior to AAV-luc transduction.

The groups were imaged for luciferase 96 hours after infection, Lee said at the 8th World Congress of the International Cartilage Repair Society, here.

The investigators discovered that the TS-5 antisense plasmid treatment decreased TS-5 gene expression more than 80%. They also found that IL-1ß stimulation increased TS-5 gene expression. However, this effect was abolished with TS-5 antisense tranfection, she said.

While the investigators identified luciferase expression in the femoral explants, they saw brighter bioluminescence in the condyles that were damaged prior to transduction.

“Our study showed that our novel antisense sequence targeting TS-5 mRNA is capable of suppressing TS-5 gene [expression],” Lee said during her presentation. “The abolishment of IL-1ß induced TS-5 overexpression suggests that our antisense treatment may be able to protect cartilage in inflammatory conditions.”

She added, “AAV is a promising delivery vehicle for articular chondrocytes in that it can transduce chondrocytes within articular cartilage with increased efficiency at damaged areas. This has additional therapeutic implications for targeted gene therapy following mechanical injury.”

The research team won the Lars Peterson Basic and Translational Science Young Investigator Award at the ICRS meeting for their paper.

Reference:

Chu C, Lee HH, Payne KA, et al. Chondroprotection of rat articular chondrocytes by ADAMTS-5 antisense sequence and gene delivery by AAV. #9.2.4. Presented at the 8th World Congress of the International Cartilage Repair Society. May 23-26, 2009. Miami.