Expression of transforming growth factor beta isoforms (TGF- 13) and receptors (TGFβ RI-RIII) in cultured human trabecular meshwork cells

Purpose: Growth factors, acting through high affinity receptors, are known to control critical cell functions via paracrine and autocrine mechanisms. The microenvironment within the human trabecular meshwork (TM) may be established and maintained by growth factors within the aqueous humoi and those produced locally by human trabecular meshwork cells (HTM). However, we lack basic information as to which growth factors and growth factor receptors are expressed by normal HTM cells. The purpose of this study was to determine which isoforms of TGF[i (TGFβ 1-3) and which TGFβ receptors (TCFβ RIRIII) are expressed by normal cultured HTM cells. Methods: Total cellular RNA isolation, DNA synthesis, RT-PCR and agarose ;>el electrophoresis were performed using well characterized HTM cell lines from 6 day 48 day, 6 month, 2 year, 18 year, 54 year and 80 year old donors. The PCR primers for TGFβ isoforms and TGFβ receptors were designed using Entrez (NCBI, Bethesda, MD.) am: Oligo 4.0 (National Biosciences Inc., Plymouth, MN.) To verify PCR product specificity, r ucleic acid sequencing was performed by cloning PCR products in the TA Cloning Vector (Invitrogen, San Diego, CA.) and sequencing with Sequenase 2.0 (United States Biochemica1, Cleveland, OH.). Results; We detected mRNA's for TGF-2 and TGF-3 in all cell lines. Messenger RNA for TGFβ-1 was variably expressed. We detected mRNA's for TCFβR-I, TGFβR-II, and TGFβR-III in all cell lines. Message for an alternatively spliced fom of TGFβR-II was detected in all cell lines and with the exception of the 54 year old cell 'ine an alternatively spliced form of TGFβ R-I was detected in all cell lines. Conclusion: These results indicate that cultured HTM cells express all TGFβ isoforms and receptor types. The interaction of members of the TGFβ family within the human TM may be important t'or normal function.