Different Stages Of Hair Cycle Research Articles

Expression pattern of mTOR subunits Raptor and Rictor in mouse hair follicle cycle

To detemine the expression pattern of mTOR complex subunits Raptor and Rictor in the hair follicles of mice at different hair follicle stages, and to explore its significance. Methods: Immunostaining of Ki-67, a proliferative marker, was used to determine the precise hair follicle stages of mouse dorsal skin at different postnatal time points. Real-time PCR was used to detect the mRNA expression of Raptor and Rictor in mouse dorsal skin at 43 days after birth (P43, early telogen), 56 days after birth (P56, mid-telogen), 69 days after birth (P69, late telogen) and 74 days after birth (P74, early anagen). The expression intensity and localization of Raptor and Rictor at different stages of hair cycle were tested by co-immumostaining. Results: Ki-67 immunostaining showed that the time points (P43, P56, P69, P74) and hair follicle stages (early telogen, mid-telogen, late telogen, early anagen) of the dorsal skin were consistent with each other. The results of real-time PCR and immunostaining were consistent, showing that the expression of Raptor and Rictor did not changed in the early-, mid-, late telogen, and early anagen. However, Raptor was specifically expressed in the bulge where hair follicle stem cells (HFSCs) are residing in, and Rictor was mainly detected in inner root sheath (IRS) cells. Conclusion: The expression of Raptor and Rictor does not altered in the hair follicles at different hair follicle stages, but Raptor and Rictor are specifically expressed in the HFSCs and IRS cells, respectively, indicating that Raptor might be a molecular marker for HFSCs, and Rictor might be involved in the maintenance of IRS and formation of hair shaft.

MicroRNA expression in murine skin at different stages of hair cycle: a preliminary study

Objective To screen differentially expressed microRNAs at different stages of hair cycle in a murine model.Methods This study included 30 inbred female C57BL/6 mice (age,6-8 weeks; body weight,15-18 grams).Hair growth cycle was induced in the back skin of C57BL/6 mice by application of wax/rosin followed by depilation under anesthesia witl 1％ chloral hydrate.Three mice were sacrificed by cervical dislocation on day 0,8 and 20 after the induction,and skin tissue was achieved from the same depilated areas parallel to the spine.Total RNAs were extracted from the murine skin and subjected to microarray analysis of microRNA expression.Results Compared with telogen skin,the murine anagen skin showed a higher expression of miR-690,obselote-49 and miR-1308,but a lower expression of miR-291a-5p and miR-212.The expressions of miR-690,obselote-49 and miR-31 were significantly up-regulated,while those of miR-127-3p and miR-212 were downregulated in the catagen skin in comparison with the telogen skin.Conclusion Seven microRNAs are identified in this study to be differentially expressed in murine skin between different stages of hair cycle,which may provide a direction for future research. Key words: Hair; MicroRNAs

Expression of parathyroid hormone (PTH)/PTH-related peptide receptor messenger ribonucleic acid in mice hair cycle

There is increasing evidence that parathyroid hormone (PTH) and PTH-related peptide (PTHrP) are involved in normal skin cell growth, influence the proliferation and differentiation of the epidermis and hair follicle. PTHrP and PTH/PTHrP receptor show prominent cutaneous expression, may exert important paracrine and/or autocrine functions. The expression of PTH/PTHrP receptor in different stages of hair cycle is unknown. Therefore, we examined the amount of PTH/PTHrP mRNA in C57BL/6 mice skin at different stages of hair cycle by relatively quantitative reverse transcription-polymerase chain reaction (RT-PCR), and investigated the localization of this receptor in mice skin by in situ hybridization. The expression of PTH/PTHrP receptor mRNA were higher in anagen, but significantly lower in catagen and telogen. Then, the PTH/PTHrP receptor mRNA was located in the inner root sheath (IRS) in anagen and catagen, but was not detected in telogen hair follicles, although it was expressed weakly in dermis. The variety of the PTH/PTHrP receptor mRNA expression during hair cycling suggest that PTH, PTHrP and their receptors might participate in the regulation of hair cycle in mice skin.