METHODS: HDAC1/2 or HDAC3 were inducibly deleted in MG epithelial cells of adult mice. The morphology of MG was examined. Proliferation, apoptosis, and expression of MG acinus and duct marker genes, meibocyte differentiation genes, and HDAC target genes, were analyzed via immunofluorescence, TUNEL assay, and RNA in situ hybridization.
RESULTS: Co-deletion of HDAC1/2 in MG epithelium caused gradual loss of acini and formation of cyst-like structures in the central duct. These phenotypes required homozygous deletion of both HDAC1 and HDAC2, indicating that they function redundantly in the adult MG. Short-term deletion of HDAC1/2 in MG epithelium had little effect on meibocyte maturation but caused decreased proliferation of acinar basal cells, excessive DNA damage, ectopic apoptosis, and increased p53 acetylation and p16 expression in the MG. By contrast, HDAC3 deletion in MG epithelium caused dilation of central duct, atrophy of acini, defective meibocyte maturation, increased acinar basal cell proliferation, and ectopic apoptosis and DNA damage. Levels of p53 acetylation and p21 expression were elevated in HDAC3-deficient MGs, while the expression of the differentiation regulator PPARγ and the differentiation markers PLIN2 and FASN was downregulated.
CONCLUSIONS: HDAC1 and HDAC2 function redundantly in adult Meibomian gland epithelial progenitor cells and are essential for their proliferation and survival, but not for acinar differentiation, while HDAC3 is required to limit acinar progenitor cell proliferation and permit differentiation. HDAC1/2 and HDAC3 have partially overlapping roles in maintaining survival of MG cells.
方法:在成年小鼠的MG上皮细胞中诱导HDAC1/2或HDAC3的缺失。检查了MG的形态。扩散,凋亡,以及MG腺泡和导管标记基因的表达,细胞分化基因,和HDAC靶基因,通过免疫荧光分析,TUNEL检测,和RNA原位杂交。
结果:MG上皮中HDAC1/2的共缺失导致腺泡逐渐消失,并在中央导管中形成囊样结构。这些表型需要HDAC1和HDAC2的纯合缺失,表明它们在成年MG中冗余地发挥功能。MG上皮中HDAC1/2的短期缺失对睑细胞成熟影响不大,但导致腺泡基底细胞增殖减少,过度的DNA损伤,异位细胞凋亡,并增加MG中p53乙酰化和p16的表达。相比之下,MG上皮HDAC3缺失导致中央导管扩张,腺泡萎缩,成膜细胞成熟缺陷,腺泡基底细胞增殖增加,异位细胞凋亡和DNA损伤。在HDAC3缺陷的MGs中,p53乙酰化和p21表达水平升高,而分化调节因子PPARγ和分化标记PLIN2和FASN的表达下调。
结论:HDAC1和HDAC2在成年睑板腺上皮祖细胞中功能冗余,对其增殖和存活至关重要,但不是腺泡分化,而HDAC3需要限制腺泡祖细胞增殖并允许分化。HDAC1/2和HDAC3在维持MG细胞存活方面具有部分重叠的作用。