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Sushil Kumar Dubey, Kabhilan Mohan, Kyung-Sik Jung, Jinze Liu, Qing Jun Wang, Mark Ellsworth Kleinman; Histone deacetylases 1 and 2 regulate chromatin modifying enzymes in mouse retinal pigment epithelium. Invest. Ophthalmol. Vis. Sci. 2021;62(8):3116.
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© ARVO (1962-2015); The Authors (2016-present)
Histone deacetylases (HDACs) 1 and 2 are highly conserved nuclear enzymes that are the core components of the corepressor complexes. HDAC1 and 2 regulate the chromatin structure and function and play a key role in critical biological processes like aging, oxidative stress, autophagy, and proteinopathy. Although these cellular processes are risk factors for several age-related eye diseases, the role of HDAC 1 and 2 are not well defined in the context of the eye and eye-related disorders. The current study explores a previously unrecognized role for HDAC1 and HDAC2 in regulating chromatin modifying enzymes in mouse RPE.
We used CRISPR/Cas9 genome editing system to generate single or combinatorial depletion of HDAC 1 and 2 in ARPE19 cells. Also, in vivo effects of HDAC 1 and 2 on chromatin modifying enzymes were determined using a transgenic mouse that expresses Cre recombinase in the RPE with floxed HDAC 1 and 2. RNA was isolated from both the ARPE19 and mouse RPE cells (at 4 and 8 weeks). qPCR was conducted to transcriptionally profile a panel of 84 epigenetic chromatin modifying genes that included DNA and histone methyltransferases, DNA and histone demethylases, histone acetyltransferases, deacetylases, phosphorylases, and set domain proteins.
Ablation of HDAC 1 or 2 leads to compensatory upregulation of other HDACs. Simultaneous deletion of HDAC 1 and 2 leads to repression of several chromatin modifying enzymes. The mouse RPE showed differential expression of approximately 16 % genes at 4-week, and this drastically increases to 50 % genes at 8-week. This is concordant with the qPCR data as 8-week old mouse RPE had lower levels of HDAC1 and 2 transcripts than 4-week old RPE. Interestingly, except class II MHC transactivator (Ciita) gene, all the other genes were downregulated. Some of the genes which display altered expression as early as 4 weeks and continue the trend in 8-week mouse RPE include Atf2, Kat2b, Ncoa1, Ube2b, Usp21, and Hsp90ab1. Interestingly, HDAC 1 and 2 depleted RPE cells show downregulation of many HDACs with the maximum depletion of HDAC11 amounting to nearly 50 % of control. Thus the data shows that combined depletion of HDAC1 and HDAC2 can alter the transcript levels of many chromatin modifying enzymes.
In conclusion, these data show that HDAC1 and HDAC2 play an essential role in the transcriptional regulation of chromatin modifiers.
This is a 2021 ARVO Annual Meeting abstract.
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