Human Hair Follicle Cells with the Cell Surface Marker CD34 Can Regenerate New Mouse Hair Follicles and Located in the Outer Root Sheath of Immunodeficient Nude Mice

Neural, adipocyte and hepatic differentiation potential of primary and secondary hair follicle stem cells isolated from Arbas Cashmere goats

Background

Arbas Cashmere goats are excellent domestic breeds with high yields of wool and cashmere. Their wool and cashmere can bring huge benefits to the livestock industry. Our studies intend to more fully understand the biological characteristics of hair follicle stem cells (HFSCs) in order to further explore the mechanisms of wool and cashmere regular regeneration. And they have been increasingly considered as promising multipotent cells in regenerative medicine because of their capacity to self-renew and differentiate. However, many aspects of the specific growth characteristics and differentiation ability of HFSCs remain unknown. This study aimed to further explore the growth characteristics and pluripotency of primary hair follicle stem cells (PHFSCs) and secondary hair follicle stem cells (SHFCs).

Results

We obtained PHFSCs and SHFSCs from Arbas Cashmere goats using combined isolation and purification methods. The proliferation and vitality of the two types of HFSCs, as well as the growth patterns, were examined. HFSC-specific markers and genes related to pluripotency, were subsequently identified. The PHFSCs and SHFSCs of Arbas Cashmere goat have a typical cobblestone morphology. Moreover, the PHFSCs and SHFSCs express HFSC surface markers, including CD34, K14, K15, K19 and LGR5. We also identified pluripotency-associated gene expression, including SOX2, OCT4 and SOX9, in PHFSCs and SHFSCs. Finally, PHFSCs and SHFSCs displayed multipotent abilities. PHFSCs and SHFSCs can be directed to differentiate into adipocyte-like, neural-like, and hepatocyte-like cells.

Conclusions

In conclusion, this study confirmed that the biological characteristics and differentiation potential of PHFSCs and SHFSCs from Arbas Cashmere goats. These findings broaden and refine our knowledge of types and characteristics of adult stem cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03420-3.

β-Catenin Signaling Evokes Hair Follicle Senescence by Accelerating the Differentiation of Hair Follicle Mesenchymal Progenitors

Rationale: β-catenin signaling controls multiple fibroblast subsets, with its overactivity promoting the differentiation of hair follicle dermal stem cells (hfDSCs) and the hyperactivation of interfollicular fibroblasts. Understanding the concept of hfDSC activation and modulation offers hope towards the therapeutic armamentarium in dermatology and related comorbidities, as well as their potential applications in gerontology (the study of physiological aging). Having a comprehensive understanding in this stochastic process could also further yield important, novel insights into the molecular basis of skin aging to improve lifespan and preventing aging-related diseases.

Methods: A new CD34CrePGR mouse line was generated. Through fate-tracing models and a series of β-catenin genetic experiments, our study depicts how the wound environment increases phosphorylated β-catenin in hfDSCs and facilitates their differentiation into dermal papilla (DP) and dermal sheath (DS). In mice carrying hfDSC-specific activated allele of β-catenin, hfDSCs accelerated their differentiation into DP cells.

Results: Notably, with β-catenin stabilization in CD34-expressing cells and potential activation of canonical Wnt signaling, the mutant mice showed a brief increase of hair density in the short term, but over time leads to a senescence phenotype developing premature canities and thinning [hair follicle (HF) miniaturization].

Conclusion: β-catenin signaling drove HF senescence by accelerating differentiation of CD34⁺ hfDSCs, resulting in phenotypes attributable to the differentiation of the hfDSCs into DP cells and the loss of their stem cell potential. Therefore, our study reveals that the regulation of β-catenin signaling in hfDSCs may potentially become an important subject for future exploration in development of clinically effective therapies for hair loss treatment and an excellent model for revealing new therapeutic approaches to reverse aging or retarding the development of alopecia.

A crucial role of fibroblast growth factor 2 in the differentiation of hair follicle stem cells toward endothelial cells in a STAT5-dependent manner

Fibroblast growth factor (FGF2) is reported to affect the proliferation, differentiation, and survival abilities of stem cells. In this study, we hypothesize that FGF2 might promote the differentiation of hair follicle stem cell (HFSCs) into endothelial cells (ECs), in a manner dependent on STAT5 activation. We first treated human HFSCs with recombinant human FGF2 to determine the involvement of FGF2 in the differentiation of HFSCs. Then the expression of EC-specific markers including von Willebrand factor (vWF), VE-cadherin, CD31, FLT-1, KDR and Tie2 was evaluated using immunofluorescence and flow cytometry, while the expression of HFSC-specific markers such as K15, K19, Lgr5, Sox9 and Lhx2 was determined by flow cytometry. Next, in vitro tube formation was performed to confirm the function of FGF2, and low-density lipoprotein (LDL) uptake by ECs and HFSCs was studied by Dil-acetylated LDL assay. In addition, we transduced FGF2-treated HFSCs with constitutive-active or dominant-negative STAT5A adenovirus vectors. FGF2 up-regulated the expression of EC-specific markers, and promoted the differentiation of HFSCs into ECs, tube formation and LDL uptake. The phosphorylated STAT5 was translocated into the nucleus of HFSCs after FGF2 treatment, but this translocation was blocked by the dominant-negative STAT5A mutant. FGF2 increased the differentiation potential through the activation of STAT5 in vivo. Taken together, we find that FGF2 promotes the differentiation of HFSCs into ECs via activated STAT5, which gives a new perspective on the role of FGF2 in the development of ischemic vascular disease.

Regenerative potential of partially differentiated mesenchymal stromal cells in a mouse model of a full-thickness skin wound

Mesenchymal stromal cells (MSCs, known as mesenchymal stem cells) are considered to be a promising therapeutic tool for many diseases. But it is still unclear which cells are more efficient and safe for wound healing and tissue regeneration for clinical applications: undifferentiated, partially differentiated stem cells or differentiated cells. In this study, we modified MSCs with keratinocyte-conditioned medium (KCM) and examined MSCs, partially differentiated MSCs (PMSCs) and differentiated cell migration, accumulation in the wounded area as well as cell regenerative efficiency in a full-thickness skin wound model. In addition to that, the impact of intradermal and intravenous cell delivery methods of wound healing was evaluated. C57BL/6J mouse compact bone MSCs were treated with a KCM for 14 days. Flow cytometry analysis showed the appearance of keratinocyte surface markers which were absent in MSCs, whereas the specific markers for MSCs were lost. Cells were injected either intravenously or intradermally in C57BL/6J mice. Wound closure, cell migration and accumulation in the wounded area were further analysed. Wound healing was assessed by the rate of wound closure and by histological evaluation. Cells were monitored using optical imaging. We demonstrated that PMSCs showed morphology similar to keratinocyte cells, had enhanced migration and increased survival at the site of injury. PMSCs had a beneficial effect on wound healing and tissue regeneration. This effect was reinforced when these cells were injected intravenously. Due to their partial differentiation status, we assume that PMSCs can differentiate more rapidly into epidermal cell lineages thus causing faster and qualitatively improved wound healing.

Cycling CD34 expression in subpopulations of head and neck squamous cell carcinoma cell lines is involved in radioresistance and change in cytokeratin expression profile

The expression of the hair follicle stem cell marker CD34 was analyzed in five different head and neck squamous cell carcinoma (HNSCC) cell lines with different antibodies. All HNSCC cell lines expressed CD34 on their cell surface. After cell cycle synchronization via serum starvation, we observed cyclic CD34 expression in HNSCC cells dependent on cell cycle progression via immunofluorescent staining and flow cytometric analysis. Investigation of the CD34(+) and CD34(-) HNSCC populations revealed most of the cells in S-phase and G2/M-Phase in CD34(+) cells in contrast to CD34(-) cells. Knockdown of CD34 in HNSCC cells led to diminished clonal expansion in a colony forming assay after subjecting the cells to ionizing radiation. Furthermore, knockdown of CD34 after cell cycle synchronization induced high CK1, CK4, and CK5 gene expression and downregulation of CK10 gene expression as shown by Taqman^® quantitative PCR analysis. The expression levels of CK1 and CK10 were verified via western blot analysis. In summary, our study shows that CD34 plays a role during cell cycle progression of head and neck squamous cell carcinoma and additionally is involved in irradiation resistance and differentiation of malignant oral keratinocytes.

Recent advances on skin-resident stem/progenitor cell functions in skin regeneration, aging and cancers and novel anti-aging and cancer therapies

Recent advances in skin-resident adult stem/progenitor cell research have revealed that these immature and regenerative cells with a high longevity provide critical functions in maintaining skin homeostasis and repair after severe injuries along the lifespan of individuals. The establishment of the functional properties of distinct adult stem/progenitor cells found in skin epidermis and hair follicles and extrinsic signals from their niches, which are deregulated during their aging and malignant transformation, has significantly improved our understanding on the etiopathogenesis of diverse human skin disorders and cancers. Particularly, enhanced ultraviolet radiation exposure, inflammation and oxidative stress and telomere attrition during chronological aging may induce severe DNA damages and genomic instability in the skin-resident stem/progenitor cells and their progenies. These molecular events may result in the alterations in key signalling components controlling their self-renewal and/or regenerative capacities as well as the activation of tumour suppressor gene products that trigger their growth arrest and senescence or apoptotic death. The progressive decline in the regenerative functions and/or number of skin-resident adult stem/progenitor cells may cause diverse skin diseases with advancing age. Moreover, the photoaging, telomerase re-activation and occurrence of different oncogenic events in skin-resident adult stem/progenitor cells may also culminate in their malignant transformation into cancer stem/progenitor cells and skin cancer initiation and progression. Therefore, the anti-inflammatory and anti-oxidant treatments and stem cell-replacement and gene therapies as well as the molecular targeting of their malignant counterpart, skin cancer-initiating cells offer great promise to treat diverse skin disorders and cancers.