Abstract
Purpose:
Insights into human lens development, homeostasis and pathology have been largely gained from the identification of genetic alterations in human cataract patients and by the in vivo investigation of lens biology using various animal models like mouse, chicken, frog and fish. In vitro models such as culture of primary or permanent lens epithelial-derived cells are important to gain mechanistic insights and have been well utilized to characterize the molecular biology of lens cells. However, gene expression in established lens epithelial cell (LEC) lines, particularly with reference to their extent to model lens biology, has not been comprehensively investigated. Therefore, we molecularly characterized two LEC lines HLE-B3 and SRA01/04, which are commonly used in lens studies, for their expression of genes important to lens biology.<br />
Methods:
The human LEC line HLE-B3 was obtained from ATCC (CRL-11421), while the LEC SRA01/04 was obtained directly from Dr. Venkat Reddy who originally derived this line. These LECs were validated for their human origin by human short tandem repeats (STRs) as recommended by the eye research community. Illumina Human-HT12 Expression BeadChip microarrays was used for whole genome expression profiling of HLE-B3 and SRA01/04. Based on analysis of the literature and the web-based lens and cataract gene discovery tool iSyTE, genes significant to lens biology were selected for further validation in LECs by RT-PCR analysis and were compared to a non-LEC line NIH3T3.<br />
Results:
Microarray analysis indicated that both HLE-B3 and SRA01/04 significantly express several genes known to be important to lens biology or cataracts. These genes identified by microarrays are: PAX6, ZEB2, PVRL3, SPARC, COL4A1, SLC16A12, LAMC1, PXDN, ALDH7A1, LEPREL1, ETV5, DKK3, CRYAB, CRYBB2, TDRD7, STX3, DHX32, SFRP1, ALDH1A3, CRIM1, STRA6, ETV6, EPHA2, ADAMTSL4, MAFG, CAPRIN2, and LAMA1. Significantly, as previously reported by Andley et al. (IOVS 1994 35:3094-3102) microarray data validates that the HLE-B3 line expresses CRYBB2. Moreover, compared to NIH3T3 cells, both LECs exhibited enriched expression of PAX6, FOXE3, PROX1, ALDH1A1 and DKK3.<br />
Conclusions:
In sum, human LECs HLEB3 and SRA01/04 retain the expression of lens epithelium-enriched genes including PAX6, FOXE3, PVRL3, ZEB2 and SPARC, while also expressing certain transition zone and fiber cell-enriched genes.<br />