PURPOSE: ABCG2 is a putative marker of progenitor cells, including the corneal epithelium. The authors investigated whether ABCG2 functions in the homeostasis of corneal epithelial cells using abcg2 knockout (KO) mice and corneal epithelial cell lines. METHODS: abcg2 KO mice and a spontaneously immortalized murine corneal epithelial cell line (TKE2) were used for experiments. Flow cytometry was used to determine the presence of side population (SP) cells based on the ability of ABCG2 to efflux Hoechst 33342 dye. Expression of ABCG2 was also examined by RT-PCR. Cytotoxicity assay (IC(50)) and propidium iodide staining were performed in semiconfluent cells treated with hypoxia (1% O(2)) or with the pro-oxidant mitoxantrone. RESULTS: abcg2 KO mice had a normal corneal epithelial phenotype; however, cultured abcg2 KO epithelial cells were prone to oxidative damage by mitoxantrone. TKE2 cells were resistant to mitoxantrone at low doses, but higher concentrations were toxic in a dose-dependent manner. Coculture with the ABCG2 inhibitors reserpine and Ko143 inhibited resistance to mitoxantrone, with a statistically higher cell death ratio. abcg2 KO cells were also significantly more sensitive to hypoxia than were wild-type control cells. CONCLUSIONS: ABCG2 may protect corneal epithelial progenitor SP cells against oxidative stress induced by toxins and hypoxia.
PURPOSE:ABCG2 is a putative marker of progenitor cells, including the corneal epithelium. The authors investigated whether ABCG2 functions in the homeostasis of corneal epithelial cells using abcg2 knockout (KO) mice and corneal epithelial cell lines. METHODS:abcg2 KO mice and a spontaneously immortalized murine corneal epithelial cell line (TKE2) were used for experiments. Flow cytometry was used to determine the presence of side population (SP) cells based on the ability of ABCG2 to efflux Hoechst 33342 dye. Expression of ABCG2 was also examined by RT-PCR. Cytotoxicity assay (IC(50)) and propidium iodide staining were performed in semiconfluent cells treated with hypoxia (1% O(2)) or with the pro-oxidant mitoxantrone. RESULTS:abcg2 KO mice had a normal corneal epithelial phenotype; however, cultured abcg2 KO epithelial cells were prone to oxidative damage by mitoxantrone. TKE2 cells were resistant to mitoxantrone at low doses, but higher concentrations were toxic in a dose-dependent manner. Coculture with the ABCG2 inhibitors reserpine and Ko143 inhibited resistance to mitoxantrone, with a statistically higher cell death ratio. abcg2 KO cells were also significantly more sensitive to hypoxia than were wild-type control cells. CONCLUSIONS:ABCG2 may protect corneal epithelial progenitor SP cells against oxidative stress induced by toxins and hypoxia.
Authors: M Kubota; Y B Shui; M Liu; F Bai; A J Huang; N Ma; D C Beebe; C J Siegfried Journal: Free Radic Biol Med Date: 2016-07-19 Impact factor: 7.376
Authors: Rohaina Che Man; Then Kong Yong; Ng Min Hwei; Wan Haslina Wan Abdul Halim; Aida Zairani Mohd Zahidin; Roszalina Ramli; Aminuddin Bin Saim; Ruszymah Binti Hj Idrus Journal: Mol Vis Date: 2017-11-21 Impact factor: 2.367
Authors: Graziella Pellegrini; Alessandro Lambiase; Claudio Macaluso; Augusto Pocobelli; Sophie Deng; Gian Maria Cavallini; Roza Esteki; Paolo Rama Journal: Regen Med Date: 2016-04-19 Impact factor: 3.806