ADAM and ADAMTS gene expression in native and wound healing human lens epithelial cells

The ADAMs (a disintegrin and metalloproteinase) and the ADAMTSs (a disintegrin and metalloproteinase with thrombospondin-like motifs) are extracellular proteases that mediate cellular interactions and cell signaling via the modulation of adhesion and the cleavage of cell surface protein ectodomains and extracellular matrix molecules. Gene expression profiling was undertaken to better understand the role of the ADAM and ADAMTS families in the clear native human lenses and following surgical injury with particular relevance to posterior capsule opacification.

To carry out profile analysis, the lens (t=0d) was dissected into three regions; anterior epithelia, equatorial region, and fiber cells. Capsular bag culture was undertaken as a means of assessing short-term changes (t=6d) and post-cataractous lens capsular bags (ex vivo) were used to predict long-term changes in ADAM/ADAMTS gene expression. RNA was isolated and quantitative real-time (TaqMan) reverse transcription-PCR (RT-PCR) performed. Data were analyzed in terms of cycle threshold number (C(T)) and also normalized relative to endogenous 18S rRNA.

High expression of ADAM-9, -10, -15, and -17 was detected in all native lens regions. ADAM-15 expression was a characteristic of the native lens epithelia more than the fibers. Post-surgical injury, lens capsular bags showed a positive shift in ADAM/ADAMTS expression that was significant for ADAM-9, -15, and ADAMTS-3. Ex vivo capsular bags, with a long-term post surgical injury period, maintained high expression of ADAM-9 and -10 genes.

The native human lens expresses ADAM and ADAMTS genes that are differentially regulated following surgical injury. Roles in maintaining cellular adhesion may be of particular importance to native lens tissue integrity and may be lost in the lens wound healing response following cataract surgery.