Construction of eukaryotic plasmid expressing human transforming growth factor beta-induced gene and its influence on human corneal epithelial cell / 中华实验眼科杂志

ABSTRACT

Background The human transforming growth factor beta-induced gene (TGFBI) is the first determined pathogenic gene to corneal dystrophy.But the molecular genetic mechanism is completely unknown.The study of concerning role of TGFBI is very important for us understand the physiological function of cornea,and the pathogenesis of corneal dystrophy.Objective The vector of human transforming growth factor beta-induced gene (TGFBI) in eukaryotic expression was constructed and transfected into the human corneal epithelial cells in order to explore its influence on the growth of human corneal epithelial cells.Methods Total RNA was extracted from normal donor cornea tissue and cDNA was obtained by reverse transcription.TGFBI cDNA was synthesized by reverse transcription-PCR and cloned into pCMV-N-HA vector and identified by sequencing with PCR and EcoRV,XhoI double restriction endonuclease.The cells were grouped into recombinant pCMV-N-HA-TGFBI plasmid group,pCMVN-HA plasmid group,non-transfected group and pGFP-C2 transfected group.The recombinant pCMV-N-HA-TGFBI plasmid was transfected to human corneal epithelial cells and identified by observing the expression of enhanced green fluorescence protein(EGFP) in the cells.The TGFBI mRNA and proteins were harvested from the cells for real-time PCR analysis and Western blot assay respectively in 58 hours after transfection.The growth of the transfected cells was assessed by Cell Counting Kit-8.The expressions of matrix metalloproteinase(MMP) and tissue inhibitors of matrix metalloproteinase (TIMP) proteins and their mRNA in transfected cells were detected using SYBR fluorescence realtime PCR analysis and Western blot assay.Results The sequencing result of pCMV-N-HA-TGFBI positive clone plasmid showed that amplified TGFBI eDNA inserted into the vector at the correct sequence.EGFP was expressed in transfected cells in 48 hours after transfer of pGFP-C2 with the transfer efficacy 70％.The expression intensity of TGFBI mRNA was significantly higher in recombinant pCMV-N-HA-TGFBI plasmid group compared with pCMV-N-HA plasmid group and non-transfected group,and TGFBI protein was expressed in recombinant pCMV-N-HA-TGFBI plasmid group.No significant difference was found in the A450value among recombinant pCMV-N-HA-TGFBI plasmid group,pCMV-N-HA plasmid group and non-transfected group ( F=3.34,P＞0.05 ).The mRNA level of MMP1,MMP3in the transfected cells was significant elevated but that of TIMP1 was declined in the recombinant pCMV-N-HA-TGFBI plasmid group compared with pCMV-N-HA plasmid group and non-transfected group (all P ＜ 0.05 ).Meanwhile,the expressions of MMP1,MMP3 and TIMP1 proteins appeared the same tendency( all P＜0.05).Conclusions Eukaryotic expression vector harboring human TGFBI eDNA can be successfully constructed and efficiently overexpressed in human corneal epithelial cells.TGFBI gene is involved in the physical and pathological conditions of human corneal epithelial cells by regulating the activity of MMP1,MMP3 and TIMP1.The results offer a new approach for the study of the role of TGFBI in pathogenesis of corneal transparency.