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Signalling couples hair follicle stem cell quiescence with reduced histone H3 K4/K9/K27me3 for proper tissue homeostasis.

Lee J, Kang S, Lilja KC, Colletier KJ, Scheitz CJ, Zhang YV, Tumbar T - Nat Commun (2016)

Bottom Line: The level of marks over specific gene promoters did not correlate to mRNA level changes in quiescent HFSCs.Furthermore, removal of proliferation factors and addition of BMP4 reduced histone methylases and increased demethylases mRNAs in cultured skin epithelial cells.We conclude that signalling couples hair follicle stem cell quiescence with reduced H3 K4/K9/K27me3 levels for proper tissue homeostasis.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.

ABSTRACT
Mechanisms of plasticity to acquire different cell fates are critical for adult stem cell (SC) potential, yet are poorly understood. Reduced global histone methylation is an epigenetic state known to mediate plasticity in cultured embryonic SCs and T-cell progenitors. Here we find histone H3 K4/K9/K27me3 levels actively reduced in adult mouse skin and hair follicle stem cells (HFSCs) during G0 quiescence. The level of marks over specific gene promoters did not correlate to mRNA level changes in quiescent HFSCs. Skin hypomethylation during quiescence was necessary for subsequent progression of hair homeostasis (cycle). Inhibiting BMP signal, a known HFSC anti-proliferative factor, elevated HFSC methylation in vivo during quiescence prior to proliferation onset. Furthermore, removal of proliferation factors and addition of BMP4 reduced histone methylases and increased demethylases mRNAs in cultured skin epithelial cells. We conclude that signalling couples hair follicle stem cell quiescence with reduced H3 K4/K9/K27me3 levels for proper tissue homeostasis.

No MeSH data available.


Related in: MedlinePlus

Potential regulation of histone methylation state by histone-modifying enzymes.(a) Quantification of foci + and − in CD34+/BrdU+ cells and CD34+/Ki67+ cells (left panel), and % BrdU+ cells in CD34+/foci+ and CD34+/foci− cells. (b) H2B-GFP pulse-chase scheme to examine histone mark level relative to HFSC divisional history. (c) Skin sections and (d) FACS plots of PD21 (unchased) and PD21–49 doxy chased mice. H2B-GFP FACS signal dilutes ½ upon division. Scale bars, 50 μm. (e) % H3K9me3 foci+ in cytospin collection of FACS-isolated HFSCs with different divisional history from late anagen (left) and telogen (right) mice. (f) qRT–PCR of multiple H3 methylases and demethylases in vivo. Statistical significance was analysed using Student's t-test. Refer to Supplementary Table 1 for list of primers used. wk, week.
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f6: Potential regulation of histone methylation state by histone-modifying enzymes.(a) Quantification of foci + and − in CD34+/BrdU+ cells and CD34+/Ki67+ cells (left panel), and % BrdU+ cells in CD34+/foci+ and CD34+/foci− cells. (b) H2B-GFP pulse-chase scheme to examine histone mark level relative to HFSC divisional history. (c) Skin sections and (d) FACS plots of PD21 (unchased) and PD21–49 doxy chased mice. H2B-GFP FACS signal dilutes ½ upon division. Scale bars, 50 μm. (e) % H3K9me3 foci+ in cytospin collection of FACS-isolated HFSCs with different divisional history from late anagen (left) and telogen (right) mice. (f) qRT–PCR of multiple H3 methylases and demethylases in vivo. Statistical significance was analysed using Student's t-test. Refer to Supplementary Table 1 for list of primers used. wk, week.

Mentions: To examine how histone methyl mark levels are regulated, we considered three possibilities: (i) direct correlation with cell cycle entry; (ii) passive dilution over multiple divisions and (iii) changes in levels of histone-modifying enzymes26. We examined correlation with cell cycle entry by quantifying H3K9me3 immunofluorescence signal as foci-positive and -negative cells in CD34+ bulge cells co-stained for proliferation markers 5-bromodeoxyuridine (BrdU) or Ki67 at anagen (PD25). We found that the majority (>70%) of BrdU+ and Ki67+ HFSCs at anagen were H3K9me3 foci+ (Fig. 6a, left), suggesting that actively cycling HFSCs are generally highly methylated. The un-methylated CD34+ bulge cells (H3K9me3 foci−) showed only 6% proliferative (BrdU+) cells, whereas methylated CD34+ cells showed 30% BrdU+ cells (Fig. 6a, right). These data suggested that the high levels of marks and active cell cycle are somewhat, but not strictly, correlated in CD34+ bulge cells at anagen. In fact, at late anagen (PD34) when HFSCs are already known to have exited cells cycle and entered G0 quiescence16, the level of marks appeared still high (Fig. 1h and Supplementary Fig. 1). All these data suggested that H3K9me3 levels did not strictly correlate with cell cycle and were likely related to hair cycle stage.


Signalling couples hair follicle stem cell quiescence with reduced histone H3 K4/K9/K27me3 for proper tissue homeostasis.

Lee J, Kang S, Lilja KC, Colletier KJ, Scheitz CJ, Zhang YV, Tumbar T - Nat Commun (2016)

Potential regulation of histone methylation state by histone-modifying enzymes.(a) Quantification of foci + and − in CD34+/BrdU+ cells and CD34+/Ki67+ cells (left panel), and % BrdU+ cells in CD34+/foci+ and CD34+/foci− cells. (b) H2B-GFP pulse-chase scheme to examine histone mark level relative to HFSC divisional history. (c) Skin sections and (d) FACS plots of PD21 (unchased) and PD21–49 doxy chased mice. H2B-GFP FACS signal dilutes ½ upon division. Scale bars, 50 μm. (e) % H3K9me3 foci+ in cytospin collection of FACS-isolated HFSCs with different divisional history from late anagen (left) and telogen (right) mice. (f) qRT–PCR of multiple H3 methylases and demethylases in vivo. Statistical significance was analysed using Student's t-test. Refer to Supplementary Table 1 for list of primers used. wk, week.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835553&req=5

f6: Potential regulation of histone methylation state by histone-modifying enzymes.(a) Quantification of foci + and − in CD34+/BrdU+ cells and CD34+/Ki67+ cells (left panel), and % BrdU+ cells in CD34+/foci+ and CD34+/foci− cells. (b) H2B-GFP pulse-chase scheme to examine histone mark level relative to HFSC divisional history. (c) Skin sections and (d) FACS plots of PD21 (unchased) and PD21–49 doxy chased mice. H2B-GFP FACS signal dilutes ½ upon division. Scale bars, 50 μm. (e) % H3K9me3 foci+ in cytospin collection of FACS-isolated HFSCs with different divisional history from late anagen (left) and telogen (right) mice. (f) qRT–PCR of multiple H3 methylases and demethylases in vivo. Statistical significance was analysed using Student's t-test. Refer to Supplementary Table 1 for list of primers used. wk, week.
Mentions: To examine how histone methyl mark levels are regulated, we considered three possibilities: (i) direct correlation with cell cycle entry; (ii) passive dilution over multiple divisions and (iii) changes in levels of histone-modifying enzymes26. We examined correlation with cell cycle entry by quantifying H3K9me3 immunofluorescence signal as foci-positive and -negative cells in CD34+ bulge cells co-stained for proliferation markers 5-bromodeoxyuridine (BrdU) or Ki67 at anagen (PD25). We found that the majority (>70%) of BrdU+ and Ki67+ HFSCs at anagen were H3K9me3 foci+ (Fig. 6a, left), suggesting that actively cycling HFSCs are generally highly methylated. The un-methylated CD34+ bulge cells (H3K9me3 foci−) showed only 6% proliferative (BrdU+) cells, whereas methylated CD34+ cells showed 30% BrdU+ cells (Fig. 6a, right). These data suggested that the high levels of marks and active cell cycle are somewhat, but not strictly, correlated in CD34+ bulge cells at anagen. In fact, at late anagen (PD34) when HFSCs are already known to have exited cells cycle and entered G0 quiescence16, the level of marks appeared still high (Fig. 1h and Supplementary Fig. 1). All these data suggested that H3K9me3 levels did not strictly correlate with cell cycle and were likely related to hair cycle stage.

Bottom Line: The level of marks over specific gene promoters did not correlate to mRNA level changes in quiescent HFSCs.Furthermore, removal of proliferation factors and addition of BMP4 reduced histone methylases and increased demethylases mRNAs in cultured skin epithelial cells.We conclude that signalling couples hair follicle stem cell quiescence with reduced H3 K4/K9/K27me3 levels for proper tissue homeostasis.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.

ABSTRACT
Mechanisms of plasticity to acquire different cell fates are critical for adult stem cell (SC) potential, yet are poorly understood. Reduced global histone methylation is an epigenetic state known to mediate plasticity in cultured embryonic SCs and T-cell progenitors. Here we find histone H3 K4/K9/K27me3 levels actively reduced in adult mouse skin and hair follicle stem cells (HFSCs) during G0 quiescence. The level of marks over specific gene promoters did not correlate to mRNA level changes in quiescent HFSCs. Skin hypomethylation during quiescence was necessary for subsequent progression of hair homeostasis (cycle). Inhibiting BMP signal, a known HFSC anti-proliferative factor, elevated HFSC methylation in vivo during quiescence prior to proliferation onset. Furthermore, removal of proliferation factors and addition of BMP4 reduced histone methylases and increased demethylases mRNAs in cultured skin epithelial cells. We conclude that signalling couples hair follicle stem cell quiescence with reduced H3 K4/K9/K27me3 levels for proper tissue homeostasis.

No MeSH data available.


Related in: MedlinePlus