Project description:Hair follicles undergo recurrent cycling of controlled growth (anagen), regression (catagen), and relative quiescence (telogen) with a defined periodicity. Taking a genomics approach to study gene expression during synchronized mouse hair follicle cycling, we discovered that, in addition to circadian fluctuation, CLOCK-regulated genes are also modulated in phase with the hair growth cycle. During telogen and early anagen, circadian clock genes are prominently expressed in the secondary hair germ, which contains precursor cells for the growing follicle. Analysis of Clock and Bmal1 mutant mice reveals a delay in anagen progression, and the secondary hair germ cells show decreased levels of phosphorylated Rb and lack mitotic cells, suggesting that circadian clock genes regulate anagen progression via their effect on the cell cycle. Consistent with a block at the G1 phase of the cell cycle, we show a significant upregulation of p21 in Bmal1 mutant skin. While circadian clock mechanisms have been implicated in a variety of diurnal biological processes, our findings indicate that circadian clock genes may be utilized to modulate the progression of non-diurnal cyclic processes. To investigate the molecular control of hair follicle cycling, we profiled mRNA expression in mouse dorsal skin at multiple representative time points in the synchronized second postnatal hair growth cycle and in a depilation-induced hair growth cycle. For profiling of second synchronized and depilation-induced hair growth cycle, the same upper-mid region of dorsal skin was excised from C57BL/6 mice at representative postnatal days (P). The time points for second hair growth cycle are classified into different phases of the hair growth cycle based on established morphological guidelines as follow: early anagen (P23, P25), mid anagen (P27), late anagen (P29, P34), early catagen (P37, P39), mid catagen (P41), and telogen (P44). Depilation-induced hair growth cycle by applying wax/rosin mixture on the dorsal skin of seven-week old mice (all follicles in telogen) was performed on mice. The corresponding phases of the hair growth cycle at number of days following depilation (D) is as follow: early anagen (D3), mid anagen (D5), late anagen (D8, D12), and early catagen (D17). For each time point, multiple biological replicates were profiled, with each mouse dorsal skin separately hybridized to an Affymetrix array.
Project description:Fgf18 gene is strongly expressed in hair follicles of mouse dorsal skin during regressing (catagen) and resting (telogen) phases of hair cycle, but not in growth (anagen) phase. This study aims at identifying the effects of FGF18 local delivery on the anagen phase of hair cycle.
Project description:Hair follicles undergo recurrent cycling of controlled growth (anagen), regression (catagen), and relative quiescence (telogen) with a defined periodicity. Taking a genomics approach to study gene expression during synchronized mouse hair follicle cycling, we discovered that, in addition to circadian fluctuation, CLOCK-regulated genes are also modulated in phase with the hair growth cycle. During telogen and early anagen, circadian clock genes are prominently expressed in the secondary hair germ, which contains precursor cells for the growing follicle. Analysis of Clock and Bmal1 mutant mice reveals a delay in anagen progression, and the secondary hair germ cells show decreased levels of phosphorylated Rb and lack mitotic cells, suggesting that circadian clock genes regulate anagen progression via their effect on the cell cycle. Consistent with a block at the G1 phase of the cell cycle, we show a significant upregulation of p21 in Bmal1 mutant skin. While circadian clock mechanisms have been implicated in a variety of diurnal biological processes, our findings indicate that circadian clock genes may be utilized to modulate the progression of non-diurnal cyclic processes. To gain molecular understanding of the the hair cycle delay in Bmal mutant mice, we profiled the dorsal skin of Bmal knockout (-/-) and their heterozygous (+/-) littermates at P22. At P22, the skin samples are comparable because all the samples are in telogen just prior to the hair cycle delay was observed. Histological sections were used to classify each sample into specific stage of the hair growth cycle based on established morphological guidelines. RNA from each mouse dorsal skin were separately hybridized to an Affymetrix Mouse Gene 1.0 ST array.
Project description:Hair follicles undergo recurrent cycling of controlled growth (anagen), regression (catagen), and relative quiescence (telogen) with a defined periodicity. Taking a genomics approach to study gene expression during synchronized mouse hair follicle cycling, we discovered that, in addition to circadian fluctuation, CLOCK-regulated genes are also modulated in phase with the hair growth cycle. During telogen and early anagen, circadian clock genes are prominently expressed in the secondary hair germ, which contains precursor cells for the growing follicle. Analysis of Clock and Bmal1 mutant mice reveals a delay in anagen progression, and the secondary hair germ cells show decreased levels of phosphorylated Rb and lack mitotic cells, suggesting that circadian clock genes regulate anagen progression via their effect on the cell cycle. Consistent with a block at the G1 phase of the cell cycle, we show a significant upregulation of p21 in Bmal1 mutant skin. While circadian clock mechanisms have been implicated in a variety of diurnal biological processes, our findings indicate that circadian clock genes may be utilized to modulate the progression of non-diurnal cyclic processes. To gain molecular understanding of the the hair cycle delay in Clock mutant mice, we profiled the dorsal skin of Clock mutant and their wild-type littermates at P23. At P23, the skin samples are comparable because all the samples are in telogen just prior to the hair cycle delay was observed. Histological sections were used to classify each sample into specific stage of the hair growth cycle based on established morphological guidelines. RNA from each mouse dorsal skin were separately hybridized to an Affymetrix array.
Project description:Fgf18 gene is strongly expressed in hair follicles of mouse dorsal skin during regressing (catagen) and resting (telogen) phases of hair cycle, but not in growth (anagen) phase. This study aims at identifying the function of Fgf18 in the regulation of hair cycle.
Project description:Gene expression architecture of mouse dorsal and tail skin reveals functional differences in inflammation and cancer: TPA time course
Project description:Fgf18 gene is strongly expressed in hair follicles of mouse dorsal skin during regressing (catagen) and resting (telogen) phases of hair cycle, but not in growth (anagen) phase. This study aims at identifying the effects of FGF18 local delivery on the anagen phase of hair cycle. To define genes affected by local delivery of FGF18 during anagen phase of hair cycle, we injected FGF18 protein subcutaneously into back skin of C3H/HeN mice on day 4 of depilation-induced anagen. As control PBS was injected in place of FGF18. After 24 h (61-d-old), total RNA was isolated from the back skin and purified to poly A RNA. The RNA samples were pooled for each group. Gene expression was analyzed by one-color analysis using single array for each group.
Project description:Fgf18 gene is strongly expressed in hair follicles of mouse dorsal skin during regressing (catagen) and resting (telogen) phases of hair cycle, but not in growth (anagen) phase. This study aims at identifying the function of Fgf18 in the regulation of hair cycle. To define target genes of Fgf18 during telogen phase of hair cycle, we generated mice in which Fgf18 gene is conditionally knocked out in keratin 5-positive epithelial cells (referred to as Fgf18 cKO below). We carried out microarray experiments with mouse back skin samples harboring telogen hair follicles obtained from three 42-d-old Fgf18 cKO male mice, or from three 42-d-old C57BL/6 male mice as control. Total RNA was isolated from each mouse and further purified to polyA RNA using oligo dT30 columns. The RNA samples were pooled for each group. Gene expression was analyzed by one-color analysis using duplicate arrays for each group.
Project description:In this study, the skin tissues were harvested from the three stages of hair follicle cycling (anagen, catagen and telogen) in a fiber-producing goat breed. In total, 63,109,004 raw reads were obtained by Solexa sequencing and 61,125,752 clean reads remained for the small RNA digitalization analysis. This resulted in the identification of 399 conserved miRNAs; among these, 326 miRNAs were expressed in all three follicular cycling stages, whereas 3, 12 and 11 miRNAs were specifically expressed in anagen, catagen, and telogen, respectively. We also identified 172 potential novel miRNAs by Mireap, 36 miRNAs were expressed in all three cycling stages, whereas 23, 29 and 44 miRNAs were specifically expressed in anagen, catagen, and telogen, respectively. Gene Ontology and KEGG pathway analyses indicated that five major biological pathways (Metabolic pathways, Pathways in cancer, MAPK signalling pathway, Endocytosis and Focal adhesion) accounting for 23.08% of target genes among 278 biological functions, indicating that these pathways are likely to play significant roles during hair cycling. the skin tissues were harvested from the three stages of hair follicle cycling (anagen, catagen and telogen) in a fiber-producing goat breed