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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

BMP signalling is involved in control of the global histone marks level.(a) Noggin- or PBS-coated fluorescent microbeads were intradermally injected for 4 days in late catagen. BrdU was fed to mice in the water bottles to continuously label proliferating cells. (b) Representative images of immunofluorescence skin staining showing increased of methylation marks in Noggin-injected mice. Scale bars, 10 μm. (c) Quantification of methylation signal in bulge cells show a significant increase in cells positively bearing histone marks in Noggin-injected (black bar) mice relative to PBS control (white bar) mice (n=2 mice, N>40 hair follicles per condition, Student's t-test). (d,e) Quantification of number of CD34+ cells per bulge (d) and BrdU+ cells per bulge (e) after 4 days of injection shows no significant differences between Noggin and PBS control, suggesting lack of proliferation of bulge cells. N=2 mice per condition, n=20–40 hair follicles per mouse. (f) qRT–PCR of selected histone methylases and demethylases in keratinocytes cultured under serum (white line), serum-free (grey line) or serum-free+BMP4 (black line) conditions. Note the reduced expression of methylases and increase of demethylases upon BMP4 addition. Statistical significance was determined by Student's t-test. Results for all genes tested are shown in Supplementary Fig. 4b.
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f8: BMP signalling is involved in control of the global histone marks level.(a) Noggin- or PBS-coated fluorescent microbeads were intradermally injected for 4 days in late catagen. BrdU was fed to mice in the water bottles to continuously label proliferating cells. (b) Representative images of immunofluorescence skin staining showing increased of methylation marks in Noggin-injected mice. Scale bars, 10 μm. (c) Quantification of methylation signal in bulge cells show a significant increase in cells positively bearing histone marks in Noggin-injected (black bar) mice relative to PBS control (white bar) mice (n=2 mice, N>40 hair follicles per condition, Student's t-test). (d,e) Quantification of number of CD34+ cells per bulge (d) and BrdU+ cells per bulge (e) after 4 days of injection shows no significant differences between Noggin and PBS control, suggesting lack of proliferation of bulge cells. N=2 mice per condition, n=20–40 hair follicles per mouse. (f) qRT–PCR of selected histone methylases and demethylases in keratinocytes cultured under serum (white line), serum-free (grey line) or serum-free+BMP4 (black line) conditions. Note the reduced expression of methylases and increase of demethylases upon BMP4 addition. Statistical significance was determined by Student's t-test. Results for all genes tested are shown in Supplementary Fig. 4b.

Mentions: Because the decreased levels of methylation observed to occur by late catagen was apparent in the whole skin (Fig. 1c–g and Supplementary Fig. 1a,b), we wondered if a skin diffusible factor might be implicated in regulation. Skin at catagen/telogen lacks diffusible proliferation signals, such as epidermal growth factor (EGF) and Wnt, and elevates inhibitory signals, such as BMP14. Indeed, we find that intra-dermal injection of Noggin (Fig. 8a), a BMP antagonist31, during the long second telogen was sufficient to increase the histone H3 K4/K9/K27me3 mark levels in bulge cells (Fig. 8b,c) before activation of proliferation (Fig. 8d,e). Furthermore, withdrawal of serum (lack of proliferative signals) and addition of BMP4 (increase of repressive signal) in cultured keratinocytes downregulated a number of methylases and upregulated demethylases at their mRNA level (Fig. 8f and Supplementary Fig. 4b). Histone methylation levels did not change noticeably upon serum removal and addition of BMP4 during the 12-h course of this experiment, as judged by microscopy of immunofluorescence-labelled cells, suggesting demethylation might be a relatively slow process. Alternatively, in vitro conditions might not completely mimic the skin environment at catagen onset. Nevertheless, these results demonstrate that BMP signalling, known to induce and maintain HFSC quiescence in vivo1431 can also produce immediate changes in mRNA levels of methylases and demethylases in skin keratinocytes. These changes are consistent with an eventual decrease of methylation, which is detectable in vivo at the time of hair cycle when the BMP signals are known to be elevated and begin to act1431. Moreover, we found that bulge HFSCs depend on active BMP signals in vivo to maintain low levels of histone H3 methylation.


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)

BMP signalling is involved in control of the global histone marks level.(a) Noggin- or PBS-coated fluorescent microbeads were intradermally injected for 4 days in late catagen. BrdU was fed to mice in the water bottles to continuously label proliferating cells. (b) Representative images of immunofluorescence skin staining showing increased of methylation marks in Noggin-injected mice. Scale bars, 10 μm. (c) Quantification of methylation signal in bulge cells show a significant increase in cells positively bearing histone marks in Noggin-injected (black bar) mice relative to PBS control (white bar) mice (n=2 mice, N>40 hair follicles per condition, Student's t-test). (d,e) Quantification of number of CD34+ cells per bulge (d) and BrdU+ cells per bulge (e) after 4 days of injection shows no significant differences between Noggin and PBS control, suggesting lack of proliferation of bulge cells. N=2 mice per condition, n=20–40 hair follicles per mouse. (f) qRT–PCR of selected histone methylases and demethylases in keratinocytes cultured under serum (white line), serum-free (grey line) or serum-free+BMP4 (black line) conditions. Note the reduced expression of methylases and increase of demethylases upon BMP4 addition. Statistical significance was determined by Student's t-test. Results for all genes tested are shown in Supplementary Fig. 4b.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f8: BMP signalling is involved in control of the global histone marks level.(a) Noggin- or PBS-coated fluorescent microbeads were intradermally injected for 4 days in late catagen. BrdU was fed to mice in the water bottles to continuously label proliferating cells. (b) Representative images of immunofluorescence skin staining showing increased of methylation marks in Noggin-injected mice. Scale bars, 10 μm. (c) Quantification of methylation signal in bulge cells show a significant increase in cells positively bearing histone marks in Noggin-injected (black bar) mice relative to PBS control (white bar) mice (n=2 mice, N>40 hair follicles per condition, Student's t-test). (d,e) Quantification of number of CD34+ cells per bulge (d) and BrdU+ cells per bulge (e) after 4 days of injection shows no significant differences between Noggin and PBS control, suggesting lack of proliferation of bulge cells. N=2 mice per condition, n=20–40 hair follicles per mouse. (f) qRT–PCR of selected histone methylases and demethylases in keratinocytes cultured under serum (white line), serum-free (grey line) or serum-free+BMP4 (black line) conditions. Note the reduced expression of methylases and increase of demethylases upon BMP4 addition. Statistical significance was determined by Student's t-test. Results for all genes tested are shown in Supplementary Fig. 4b.
Mentions: Because the decreased levels of methylation observed to occur by late catagen was apparent in the whole skin (Fig. 1c–g and Supplementary Fig. 1a,b), we wondered if a skin diffusible factor might be implicated in regulation. Skin at catagen/telogen lacks diffusible proliferation signals, such as epidermal growth factor (EGF) and Wnt, and elevates inhibitory signals, such as BMP14. Indeed, we find that intra-dermal injection of Noggin (Fig. 8a), a BMP antagonist31, during the long second telogen was sufficient to increase the histone H3 K4/K9/K27me3 mark levels in bulge cells (Fig. 8b,c) before activation of proliferation (Fig. 8d,e). Furthermore, withdrawal of serum (lack of proliferative signals) and addition of BMP4 (increase of repressive signal) in cultured keratinocytes downregulated a number of methylases and upregulated demethylases at their mRNA level (Fig. 8f and Supplementary Fig. 4b). Histone methylation levels did not change noticeably upon serum removal and addition of BMP4 during the 12-h course of this experiment, as judged by microscopy of immunofluorescence-labelled cells, suggesting demethylation might be a relatively slow process. Alternatively, in vitro conditions might not completely mimic the skin environment at catagen onset. Nevertheless, these results demonstrate that BMP signalling, known to induce and maintain HFSC quiescence in vivo1431 can also produce immediate changes in mRNA levels of methylases and demethylases in skin keratinocytes. These changes are consistent with an eventual decrease of methylation, which is detectable in vivo at the time of hair cycle when the BMP signals are known to be elevated and begin to act1431. Moreover, we found that bulge HFSCs depend on active BMP signals in vivo to maintain low levels of histone H3 methylation.

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