Establishment of Angora rabbits' whisker hair follicle model and optimal culture conditions.

To establish the model of whisker hair follicle culture in vitro and explore the best culture conditions, the whisker hair follicles of Angora rabbits were separated with stereomicroscope and cultured in William's E, DMEM, MEM media. The surface of the cultured whisker hair follicles was not damaged due to manual operation, resulting in the hair shaft's growth. This indicated the success of the in vitro whisker hair follicle model. The hair shaft grew at the fastest rate in the William's E culture (p < 0.05), which was significantly higher than that in the DMEM and MEM media. The hematoxylin-eosin results showed that compared to the William's E group, the atrophy of whisker hair follicles in the DMEM and MEM media was evident, especially in the MEM medium. PCNA immunofluorescence staining was employed to detect the expression of whisker hair follicles. The results showed that the PCNA positive expression of the William's E group was significantly stronger than that of the DMEM and MEM groups. Furthermore, CCK-8 and Annexin V-FITC/PI methods were used to detect the proliferation and apoptosis of the dermal papilla cells (DPCs). The results of this study provide a model for studying the hair growth of fur animals.

miR-218-5p regulates skin and hair follicle development through Wnt/ß-catenin signaling pathway by targeting SFRP2.

The hair follicle is a complex biological system involved in a dynamic process governed by gene regulation. MicroRNAs play a critical role in the regulation of gene expression. We demonstrated that the expression of miR-218-5p and SFRP2 showed the opposite relationship in catagen and telogen phases and that miR-218-5p promoted the growth of hair shafts. The luciferase reporter assays confirmed that SFRP2 is the direct target of miR-218-5p. The expression of miR-218-5p may decrease the expression of SFRP2, which activates the Wnt signaling pathway, including the regulation of downstream genes and ß-catenin/T-cell-specific factor transcriptional activity. Moreover, miR-218-5p enhanced apoptosis, but inhibition of miR-218-5p decreased apoptosis and inhibited RAB-9 cell proliferation. In this study, we show that miR-218-5p positively regulates the Wnt signaling pathway by targeting SFRP2 and acts as a dynamic governor during skin and hair follicle development.

Characterization and Establishment of an Immortalized Rabbit Melanocyte Cell Line Using the SV40 Large T Antigen.

Melanocytes (MCs) are specialized cells that synthesize melanin within the melanosome. Cultured MCs are useful in order to study their role in relation to pigmentation. However, MC isolation is laborious and the obtained cells have a limited culture time. In this study, we transformed lentivirus-mediated simian virus 40 Large T (SV40-LT) into primary rabbit melanocytes (Pri RMCs) to establish an immortalized cell line. Morphologically, the immortalized RMCs (Im RMC) were indistinguishable from the Pri RMCs, and dendrites were visible following Dopa staining. No significant differences in cell proliferation or growth between immortalized and primary RMCs were observed. Based on melanocyte-specific markers, the expression of MITF, TYR, and TYRP1 were detected by PCR, immunofluorescence staining, and western blot analysis. Through karyotype, soft agar, and tumorigenesis assays, the immortalized RMCs did not undergo malignant transformation. Our results show that Im RMCs can be used as a tool cell for future MC studies on the pigmentation mechanisms of fur animals.

Establishment of SLC7A11-knockout mouse and its preliminary investigation in melanoma.

Solute carrier family 7 member 11 (SLC7A11)/xCT is an amino acid transporter that mediates the cystine uptake and glutamate export, participates in several malignant tumors' progression. However, the role of SLC7A11 on the occurrence and development of melanoma still remains unclear. Here, the transcribed mRNA encoding for Cas9 and sgRNA targeting SLC7A11 in vitro were microinjected into zygotes, to establish the SLC7A11 knockout (KO) mice (SLC7A11-/-). Further, we conducted melanoma-bearing mice using the metastatic melanoma cell line (B16-F10) to observe the melanoma development. There was no off-target in KO mice detected by T7E1 cleavage assay. The results showed that the tumor volume of KO mice was significantly lower than that of SLC7A11+/+ (WT) mice at 8d, 10d, 12d, 14d, and 16d (P < 0.05). The tumors of WT appeared to more disorganized morphology, more unbalanced nuclear-cytoplasmic ratio, less defined boundary, and increased tumor necrosis. And after SLC7A11 deletion, the expression of CXCL9 and TLR6 were significantly up-regulated, and that of NOS2 and CCL8 were significantly down-regulated (P < 0.01). Additionally, Ki67 immunostaining revealed lower proliferating cells in the tumors of SLC7A11 KO mice compared to WT mice. In summary, the deletion of SLC7A11 significantly inhibited the development of melanoma. Our results provide direct evidence to identify SLC7A11 as a novel target for molecular therapy and prognosis judgment of melanoma.

A Treatment Combination of IGF and EGF Promotes Hair Growth in the Angora Rabbit.

The hair follicle (HF) growth cycle is a complex, multistep biological process, for which dysfunction affects hair-related diseases in humans and wool production in animals. In this study, a treatment combination of 10 ng/mL insulin-like growth factor-1 (IGF-1) and 20 ng/mL epidermal growth factor (EGF) significantly increased the elongation length of hair shafts for cultured HFs. The combined treatment of IGF-1 and EGF enhanced the proliferation of HFs and promoted HF growth and development in vitro. In vivo, the combined treatment of IGF-1 and EGF was subcutaneously injected into the dorsal skin in HF synchronized rabbits. The IGF-1 and EGF combination promoted the transition of the hair cycle from telogen to anagen and stimulated the growth of hair shafts. This IGF-1 and EGF combination maintained the structure of the HF and enhanced the cell proliferation of outer root sheaths and the dermal papilla within rabbit skin. The combined treatment of IGF-1 and EGF regulated HF-related genes, including LEF1, CCND1 and WNT2, suggesting that IGF-1 and EGF play a positive role in HF growth and development. Utilization of the combined IGF-1 and EGF treatment may assist with hair and wool production and HF related diseases in mammals.

Analysis of Genome DNA Methylation at Inherited Coat Color Dilutions of Rex Rabbits.

Background: The dilution of color in rabbits is associated with many different genetic mechanisms that form different color groups. A number of previous studies have revealed potential regulatory mechanisms by which epigenetics regulate pigmentation. However, the genome-wide DNA methylation involved in animal coat color dilution remains unknown. Results: We compared genome-wide DNA methylation profiles in Rex rabbit hair follicles in a Chinchilla group (Ch) and a diluted Chinchilla group (DCh) through whole-genome bisulfite sequencing (WGBS). Approximately 3.5% of the cytosine sites were methylated in both groups, of which the CG methylation type was in greatest abundance. In total, we identified 126,405 differentially methylated regions (DMRs) between the two groups, corresponding to 11,459 DMR-associated genes (DMGs). Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that these DMGs were principally involved in developmental pigmentation and Wnt signaling pathways. In addition, two DMRs were randomly selected to verify that the WGBS data were reliable using bisulfite sequencing PCR, and seven DMGs were analyzed to establish the relationship between the level of DNA methylation and mRNA expression using qRT-PCR. Due to the limitation of small sample size, replication of the results with a larger sample size would be important in future studies. Conclusion: These findings provide evidence that there is an association between inherited color dilution and DNA methylation alterations in hair follicles, greatly contributing to our understanding of the epigenetic regulation of rabbit pigmentation.