Limits...
Experimental murine myopia induces collagen type Iα1 (COL1A1) DNA methylation and altered COL1A1 messenger RNA expression in sclera.

Zhou X, Ji F, An J, Zhao F, Shi F, Huang F, Li Y, Jiao S, Yan D, Chen X, Chen J, Qu J - Mol. Vis. (2012)

Bottom Line: MD was found to induce myopia in the treated eyes.Consistent with the CpG methylation, scleral COL1A1 mRNA was reduced by 57% in the MD-treated eyes compared to normal controls (p<0.05).After seven days of MD recovery, CpG methylation was significantly reduced (p=0.01).

View Article: PubMed Central - PubMed

Affiliation: School of Optometry & Ophthalmology and Eye Hospital, Wenzhou Medical College, Wenzhou, Zhejiang, China.

ABSTRACT

Purpose: To investigate whether myopia development is associated with changes of scleral DNA methylation in cytosine-phosphate-guanine (CpG) sites in the collagen 1A1 (COL1A1) promoter and messenger RNA (mRNA) levels following murine form deprivation myopia.

Methods: Fifty-seven C57BL/6 mice (postnatal day 23) were randomly assigned to four groups: (1) monocular form deprivation (MD) in which a diffuser lens was placed over one eye for 28 days; (2) normal controls without MD; (3) MD recovery in which the diffuser lens was removed for seven days; and (4) MD recovery normal controls. The DNA methylation pattern in COL1A1 promoter and exon 1 was determined by bisulfite DNA sequencing, and the COL1A1 mRNA level in sclera was determined by quantitative PCR.

Results: MD was found to induce myopia in the treated eyes. Six CpG sites in the promoter and exon 1 region of COL1A1 were methylated with significantly higher frequency in the treated eyes than normal control eyes (p<0.05), with CpG island methylation in MD-contralateral eyes being intermediate. Consistent with the CpG methylation, scleral COL1A1 mRNA was reduced by 57% in the MD-treated eyes compared to normal controls (p<0.05). After seven days of MD recovery, CpG methylation was significantly reduced (p=0.01). The methylation patterns returned to near normal level in five CpG sites, but the sixth was hypomethylated compared to normal controls.

Conclusions: In parallel with the development of myopia and the reduced COL1A1 mRNA, the frequency of methylation in CpG sites of the COL1A1 promoter/exon 1 increased during MD and returned to near normal during recovery. Thus, hypermethylation of CpG sites in the promoter/exon 1 of COL1A1 may underlie reduced collagen synthesis at the transcriptional level in myopic scleras.

Show MeSH

Related in: MedlinePlus

Amplification fragment of mouse collagen type Iα1 promoter region containing 19 cytosine-phosphate-guanine (CpG) sites. The online software P-Match 1.0 was used to predict transcription factor blinding sites. Site 9 is within the transcription factor Adf-1 binding site, and site 14 is within the transcription factor Sp1 binding site. Bold numbered cytosine-guanine (CGs) are cytosine-phosphate-guanine (CpG) sites. The notation “(+)” represents transcription factor binding to the positive strand of DNA, while “(-)” represents transcription factor binding to the negative strand of DNA. Moreover, “”? represents a partial match. Asterisks indicate significant differences between monocular deprivation–treated (MD-T) eyes and either the control or MD-recovery (MD-R) eyes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3369898&req=5

f7: Amplification fragment of mouse collagen type Iα1 promoter region containing 19 cytosine-phosphate-guanine (CpG) sites. The online software P-Match 1.0 was used to predict transcription factor blinding sites. Site 9 is within the transcription factor Adf-1 binding site, and site 14 is within the transcription factor Sp1 binding site. Bold numbered cytosine-guanine (CGs) are cytosine-phosphate-guanine (CpG) sites. The notation “(+)” represents transcription factor binding to the positive strand of DNA, while “(-)” represents transcription factor binding to the negative strand of DNA. Moreover, “”? represents a partial match. Asterisks indicate significant differences between monocular deprivation–treated (MD-T) eyes and either the control or MD-recovery (MD-R) eyes.

Mentions: CpG methylation site number 9 is within the binding site of transcription factor Adf-1, and CpG methylation site number 14 is within the binding site for transcription factor Sp1 (Figure 7). In Drosophila, Adf-1 activates the transcription of many genes [38-40]. In normal human dermal fibroblasts, Sp1 can activate the transcription of COL1A1 [41] During MD, methylation of the 9th and 14th CpG sites may suppress COL1A1 gene expression by altering Adf-1 and Sp1 binding. After MD recovery, those locations are demethylated, and allow the binding of Adf-1 and Sp1. The other four CpG sites, 1, 3, 18, and 19, which also became methylated during MD and were demethylated during recovery, are not located in transcription factor binding sites. The functions of these CpG sites are not currently known. The methylation of the CpG sites may have affected the structure of chromatin [42-44] or the binding of methyl-C-binding proteins [19] in the treated eyes of the MD group. Interestingly, the 11th CpG site, which underwent significant methylation and demethylation during treatment and recovery, is located near the transcription start site of COL1A1. The loss of CpG methylation at this site in the MD recovery eyes may promote the transcription of COL1A1, which suggests renewed transcription of COL1A1 under these conditions.


Experimental murine myopia induces collagen type Iα1 (COL1A1) DNA methylation and altered COL1A1 messenger RNA expression in sclera.

Zhou X, Ji F, An J, Zhao F, Shi F, Huang F, Li Y, Jiao S, Yan D, Chen X, Chen J, Qu J - Mol. Vis. (2012)

Amplification fragment of mouse collagen type Iα1 promoter region containing 19 cytosine-phosphate-guanine (CpG) sites. The online software P-Match 1.0 was used to predict transcription factor blinding sites. Site 9 is within the transcription factor Adf-1 binding site, and site 14 is within the transcription factor Sp1 binding site. Bold numbered cytosine-guanine (CGs) are cytosine-phosphate-guanine (CpG) sites. The notation “(+)” represents transcription factor binding to the positive strand of DNA, while “(-)” represents transcription factor binding to the negative strand of DNA. Moreover, “”? represents a partial match. Asterisks indicate significant differences between monocular deprivation–treated (MD-T) eyes and either the control or MD-recovery (MD-R) eyes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369898&req=5

f7: Amplification fragment of mouse collagen type Iα1 promoter region containing 19 cytosine-phosphate-guanine (CpG) sites. The online software P-Match 1.0 was used to predict transcription factor blinding sites. Site 9 is within the transcription factor Adf-1 binding site, and site 14 is within the transcription factor Sp1 binding site. Bold numbered cytosine-guanine (CGs) are cytosine-phosphate-guanine (CpG) sites. The notation “(+)” represents transcription factor binding to the positive strand of DNA, while “(-)” represents transcription factor binding to the negative strand of DNA. Moreover, “”? represents a partial match. Asterisks indicate significant differences between monocular deprivation–treated (MD-T) eyes and either the control or MD-recovery (MD-R) eyes.
Mentions: CpG methylation site number 9 is within the binding site of transcription factor Adf-1, and CpG methylation site number 14 is within the binding site for transcription factor Sp1 (Figure 7). In Drosophila, Adf-1 activates the transcription of many genes [38-40]. In normal human dermal fibroblasts, Sp1 can activate the transcription of COL1A1 [41] During MD, methylation of the 9th and 14th CpG sites may suppress COL1A1 gene expression by altering Adf-1 and Sp1 binding. After MD recovery, those locations are demethylated, and allow the binding of Adf-1 and Sp1. The other four CpG sites, 1, 3, 18, and 19, which also became methylated during MD and were demethylated during recovery, are not located in transcription factor binding sites. The functions of these CpG sites are not currently known. The methylation of the CpG sites may have affected the structure of chromatin [42-44] or the binding of methyl-C-binding proteins [19] in the treated eyes of the MD group. Interestingly, the 11th CpG site, which underwent significant methylation and demethylation during treatment and recovery, is located near the transcription start site of COL1A1. The loss of CpG methylation at this site in the MD recovery eyes may promote the transcription of COL1A1, which suggests renewed transcription of COL1A1 under these conditions.

Bottom Line: MD was found to induce myopia in the treated eyes.Consistent with the CpG methylation, scleral COL1A1 mRNA was reduced by 57% in the MD-treated eyes compared to normal controls (p<0.05).After seven days of MD recovery, CpG methylation was significantly reduced (p=0.01).

View Article: PubMed Central - PubMed

Affiliation: School of Optometry & Ophthalmology and Eye Hospital, Wenzhou Medical College, Wenzhou, Zhejiang, China.

ABSTRACT

Purpose: To investigate whether myopia development is associated with changes of scleral DNA methylation in cytosine-phosphate-guanine (CpG) sites in the collagen 1A1 (COL1A1) promoter and messenger RNA (mRNA) levels following murine form deprivation myopia.

Methods: Fifty-seven C57BL/6 mice (postnatal day 23) were randomly assigned to four groups: (1) monocular form deprivation (MD) in which a diffuser lens was placed over one eye for 28 days; (2) normal controls without MD; (3) MD recovery in which the diffuser lens was removed for seven days; and (4) MD recovery normal controls. The DNA methylation pattern in COL1A1 promoter and exon 1 was determined by bisulfite DNA sequencing, and the COL1A1 mRNA level in sclera was determined by quantitative PCR.

Results: MD was found to induce myopia in the treated eyes. Six CpG sites in the promoter and exon 1 region of COL1A1 were methylated with significantly higher frequency in the treated eyes than normal control eyes (p<0.05), with CpG island methylation in MD-contralateral eyes being intermediate. Consistent with the CpG methylation, scleral COL1A1 mRNA was reduced by 57% in the MD-treated eyes compared to normal controls (p<0.05). After seven days of MD recovery, CpG methylation was significantly reduced (p=0.01). The methylation patterns returned to near normal level in five CpG sites, but the sixth was hypomethylated compared to normal controls.

Conclusions: In parallel with the development of myopia and the reduced COL1A1 mRNA, the frequency of methylation in CpG sites of the COL1A1 promoter/exon 1 increased during MD and returned to near normal during recovery. Thus, hypermethylation of CpG sites in the promoter/exon 1 of COL1A1 may underlie reduced collagen synthesis at the transcriptional level in myopic scleras.

Show MeSH
Related in: MedlinePlus