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CtBP1 overexpression in keratinocytes perturbs skin homeostasis.

Deng H, Li F, Li H, Deng Y, Liu J, Wang D, Han G, Wang XJ, Zhang Q - J. Invest. Dermatol. (2013)

Bottom Line: Surprisingly, K5.CtBP1 pups also exhibited a hair loss phenotype.Molecular studies revealed that CtBP1 directly suppressed Dlx3 transcription.In summary, this CtBP1 transgenic model provides in vivo evidence for certain CtBP1 functions predicted from in vitro studies, reveals--to our knowledge--previously unreported functions and transcriptional activities of CtBP1 in the context of epithelial-mesenchymal interplay, and suggests that CtBP1 has a pathogenic role in hair follicle morphogenesis and differentiation.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Dermatology, University of Colorado Denver, Aurora, Colorado, USA [2] Department of Pathology, University of Colorado Denver, Aurora, Colorado, USA [3] Department of Dermatology, The Sixth People's Hospital of Shanghai, Shanghai Jiaotong University, Shanghai, China.

ABSTRACT
Carboxyl-terminal-binding protein-1 (CtBP1) is a transcriptional corepressor with multiple in vitro targets, but its in vivo functions are largely unknown. We generated keratinocyte-specific CtBP1 transgenic mice with a keratin-5 promoter (K5.CtBP1) to probe the pathological roles of CtBP1. At transgene expression levels comparable to endogenous CtBP1 in acute skin wounds, the K5.CtBP1 epidermis displayed hyperproliferation, loss of E-cadherin, and failed terminal differentiation. Known CtBP1 target genes associated with these processes, e.g., p21, Brca1, and E-cadherin, were downregulated in K5.CtBP1 skin. Surprisingly, K5.CtBP1 pups also exhibited a hair loss phenotype. We found that expression of the Distal-less 3 (Dlx3), a critical regulator of hair follicle differentiation and cycling, was decreased in K5.CtBP1 mice. Molecular studies revealed that CtBP1 directly suppressed Dlx3 transcription. Consistently, K5.CtBP1 mice displayed abnormal hair follicles with decreased expression of Dlx3 downstream targets Gata3, Hoxc13, and hair keratins. In summary, this CtBP1 transgenic model provides in vivo evidence for certain CtBP1 functions predicted from in vitro studies, reveals--to our knowledge--previously unreported functions and transcriptional activities of CtBP1 in the context of epithelial-mesenchymal interplay, and suggests that CtBP1 has a pathogenic role in hair follicle morphogenesis and differentiation.

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Down-regulation of Dlx3 target genes in K5.CtBP1 skins. (A) WT and K5.CtBP1 skins were used for qRT-PCR. Gata3 mRNA decreased to 0.35±0.07 and Hoxc13 mRNA decreased to 0.11±0.06 in transgenic skin. **: p<0.01. (B) Immunofluorescence staining (green) of Gata3 and Hoxc13 demonstrates decreased expression in K5.CtBP1 hair follicles compared with WT follicles. Keratin 14 (red) was used as a counterstain. Scale bar: 15 μm. (C) WT and K5.CtBP1 skins were used for qRT-PCR Keratin 25 (KRT25), keratin 27 (KRT27), keratin 28 (KRT28), and keratin 71 (KRT71) mRNA expression levels. Error bars indicate s.d. (n=3), and significance was determined using Student’s t test. **: p<0.01.
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Figure 6: Down-regulation of Dlx3 target genes in K5.CtBP1 skins. (A) WT and K5.CtBP1 skins were used for qRT-PCR. Gata3 mRNA decreased to 0.35±0.07 and Hoxc13 mRNA decreased to 0.11±0.06 in transgenic skin. **: p<0.01. (B) Immunofluorescence staining (green) of Gata3 and Hoxc13 demonstrates decreased expression in K5.CtBP1 hair follicles compared with WT follicles. Keratin 14 (red) was used as a counterstain. Scale bar: 15 μm. (C) WT and K5.CtBP1 skins were used for qRT-PCR Keratin 25 (KRT25), keratin 27 (KRT27), keratin 28 (KRT28), and keratin 71 (KRT71) mRNA expression levels. Error bars indicate s.d. (n=3), and significance was determined using Student’s t test. **: p<0.01.

Mentions: To further study the functional consequence of CtBP1-mediated repression of the Dlx3 gene, we examined mRNA levels of Dlx3 transcriptional targets in K5.CtBP1 skin. Gata3 and Hoxc13 are transcription factors affecting hair differentiation (Godwin and Capecchi, 1998; Kurek et al., 2007). Decreased Gata3 and Hoxc13 expression was detected in genetically engineered K14-Dlx3−/− mice (Hwang et al., 2008). As shown in Fig. 6A, CtBP1 transgene expression decreased mRNA levels of Gata3 to 60% of that seen in control skin; small but significant changes. On the contrary, expression of Hoxc13 was decreased to 10% of that seen in control skin by CtBP1 transgene expression (Fig. 6A). Fig. 6B illustrates the decrease of Gata3 and Hoxc13 expression in hair follicles of K5.CtBP1 mice.


CtBP1 overexpression in keratinocytes perturbs skin homeostasis.

Deng H, Li F, Li H, Deng Y, Liu J, Wang D, Han G, Wang XJ, Zhang Q - J. Invest. Dermatol. (2013)

Down-regulation of Dlx3 target genes in K5.CtBP1 skins. (A) WT and K5.CtBP1 skins were used for qRT-PCR. Gata3 mRNA decreased to 0.35±0.07 and Hoxc13 mRNA decreased to 0.11±0.06 in transgenic skin. **: p<0.01. (B) Immunofluorescence staining (green) of Gata3 and Hoxc13 demonstrates decreased expression in K5.CtBP1 hair follicles compared with WT follicles. Keratin 14 (red) was used as a counterstain. Scale bar: 15 μm. (C) WT and K5.CtBP1 skins were used for qRT-PCR Keratin 25 (KRT25), keratin 27 (KRT27), keratin 28 (KRT28), and keratin 71 (KRT71) mRNA expression levels. Error bars indicate s.d. (n=3), and significance was determined using Student’s t test. **: p<0.01.
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Related In: Results  -  Collection

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Figure 6: Down-regulation of Dlx3 target genes in K5.CtBP1 skins. (A) WT and K5.CtBP1 skins were used for qRT-PCR. Gata3 mRNA decreased to 0.35±0.07 and Hoxc13 mRNA decreased to 0.11±0.06 in transgenic skin. **: p<0.01. (B) Immunofluorescence staining (green) of Gata3 and Hoxc13 demonstrates decreased expression in K5.CtBP1 hair follicles compared with WT follicles. Keratin 14 (red) was used as a counterstain. Scale bar: 15 μm. (C) WT and K5.CtBP1 skins were used for qRT-PCR Keratin 25 (KRT25), keratin 27 (KRT27), keratin 28 (KRT28), and keratin 71 (KRT71) mRNA expression levels. Error bars indicate s.d. (n=3), and significance was determined using Student’s t test. **: p<0.01.
Mentions: To further study the functional consequence of CtBP1-mediated repression of the Dlx3 gene, we examined mRNA levels of Dlx3 transcriptional targets in K5.CtBP1 skin. Gata3 and Hoxc13 are transcription factors affecting hair differentiation (Godwin and Capecchi, 1998; Kurek et al., 2007). Decreased Gata3 and Hoxc13 expression was detected in genetically engineered K14-Dlx3−/− mice (Hwang et al., 2008). As shown in Fig. 6A, CtBP1 transgene expression decreased mRNA levels of Gata3 to 60% of that seen in control skin; small but significant changes. On the contrary, expression of Hoxc13 was decreased to 10% of that seen in control skin by CtBP1 transgene expression (Fig. 6A). Fig. 6B illustrates the decrease of Gata3 and Hoxc13 expression in hair follicles of K5.CtBP1 mice.

Bottom Line: Surprisingly, K5.CtBP1 pups also exhibited a hair loss phenotype.Molecular studies revealed that CtBP1 directly suppressed Dlx3 transcription.In summary, this CtBP1 transgenic model provides in vivo evidence for certain CtBP1 functions predicted from in vitro studies, reveals--to our knowledge--previously unreported functions and transcriptional activities of CtBP1 in the context of epithelial-mesenchymal interplay, and suggests that CtBP1 has a pathogenic role in hair follicle morphogenesis and differentiation.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Dermatology, University of Colorado Denver, Aurora, Colorado, USA [2] Department of Pathology, University of Colorado Denver, Aurora, Colorado, USA [3] Department of Dermatology, The Sixth People's Hospital of Shanghai, Shanghai Jiaotong University, Shanghai, China.

ABSTRACT
Carboxyl-terminal-binding protein-1 (CtBP1) is a transcriptional corepressor with multiple in vitro targets, but its in vivo functions are largely unknown. We generated keratinocyte-specific CtBP1 transgenic mice with a keratin-5 promoter (K5.CtBP1) to probe the pathological roles of CtBP1. At transgene expression levels comparable to endogenous CtBP1 in acute skin wounds, the K5.CtBP1 epidermis displayed hyperproliferation, loss of E-cadherin, and failed terminal differentiation. Known CtBP1 target genes associated with these processes, e.g., p21, Brca1, and E-cadherin, were downregulated in K5.CtBP1 skin. Surprisingly, K5.CtBP1 pups also exhibited a hair loss phenotype. We found that expression of the Distal-less 3 (Dlx3), a critical regulator of hair follicle differentiation and cycling, was decreased in K5.CtBP1 mice. Molecular studies revealed that CtBP1 directly suppressed Dlx3 transcription. Consistently, K5.CtBP1 mice displayed abnormal hair follicles with decreased expression of Dlx3 downstream targets Gata3, Hoxc13, and hair keratins. In summary, this CtBP1 transgenic model provides in vivo evidence for certain CtBP1 functions predicted from in vitro studies, reveals--to our knowledge--previously unreported functions and transcriptional activities of CtBP1 in the context of epithelial-mesenchymal interplay, and suggests that CtBP1 has a pathogenic role in hair follicle morphogenesis and differentiation.

Show MeSH
Related in: MedlinePlus