Hair Follicle Stem Cells Derived from Single Rat Vibrissa via Organ Culture Reconstitute Hair Follicles in Vivo

Hair Growth Promoting Effects of Solubilized Sturgeon Oil and Its Correlation with the Gut Microbiome

Androgenetic alopecia is a common disease that occurs in both men and women. Several approved medications have been used to treat this condition, but they are associated with certain side effects. Therefore, use of extracts derived from natural products, such as Siberian sturgeon (Acipenser baerii), and the regulation of the gut microbiota have become important topics of research. Sturgeon is known for its high nutritional value and anti-inflammatory properties; however, its effects on androgenetic alopecia and gut microbiota remain uncharacterized. Here, we aimed to investigate whether solubilized sturgeon oil (SSO) promotes hair growth and regulates the gut microbiome. C57BL/6 mice were divided into four groups. Three groups received topical applications of distilled water, SSO, or minoxidil, and one group was orally administered SSO. Each treatment was administered over 4 weeks. Histopathological analysis revealed a significant increase in follicle number (p < 0.001) and follicle diameter (p < 0.05). Immunohistochemical analysis revealed upregulation of β-catenin and ERK-1, markers involved in hair growth-promoting pathways. Furthermore, microbiome analysis revealed that the reduced gut microbiota was negatively correlated with these markers. Our findings indicate that oral administration of SSO promotes hair growth and regulates the abundance of hair growth-promoting gut microbiota.

Evaluating the Impact of Hair Care Product Exposure on Hair Follicle and Scalp Health

Human hair follicles traverse the epidermis and dermis, and are comprised of specialised cells including dermal papilla cells (DPCs). DPCs play a critical role in the development and growth of both hair and follicle structure. While exposure of DPCs to undiluted exogenous compounds is unlikely, exposure to diluted compounds is possible should dermal penetration occur. The goal of this study was to evaluate the impact on hair and scalp health following application of a hair care product. Due to the lack of standardised and validated test systems for evaluating hair follicle health, the HairSkin® model, which uses intact human scalp samples, was adapted to evaluate hair follicle and scalp health. Similarly, the Franz diffusion cell assay and matrix-assisted laser desorption ionisation-Fourier transform ion cyclotron resonance (MALDI-FTICR) were adapted to evaluate dermal penetration. The results of this study demonstrate that application of the hair care product does not result in appreciable dermal penetration, suggesting that DPCs are unlikely to be exposed to undiluted product. Additionally, hair follicle health was not impacted following product application. While this study is exploratory, these results suggest that the combination of test systems utilised herein provides valuable insight and warrants further development and validation.

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.

Regulation of signaling pathways in hair follicle stem cells

Hair follicle stem cells (HFSCs) reside in the bulge region of the outer root sheath of the hair follicle. They are considered slow-cycling cells that are endowed with multilineage differentiation potential and superior proliferative capacity. The normal morphology and periodic growth of HFSCs play a significant role in normal skin functions, wound repair and skin regeneration. The HFSCs involved in these pathophysiological processes are regulated by a series of cell signal transduction pathways, such as lymphoid enhancer factor/T-cell factor, Wnt/β-catenin, transforming growth factor-β/bone morphogenetic protein, Notch and Hedgehog. The mechanisms of the interactions among these signaling pathways and their regulatory effects on HFSCs have been previously studied, but many mechanisms are still unclear. This article reviews the regulation of hair follicles, HFSCs and related signaling pathways, with the aims of summarizing previous research results, revealing the regulatory mechanisms of HFSC proliferation and differentiation and providing important references and new ideas for treating clinical diseases.

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.

Functional hair follicle regeneration: an updated review

The hair follicle (HF) is a highly conserved sensory organ associated with the immune response against pathogens, thermoregulation, sebum production, angiogenesis, neurogenesis and wound healing. Although recent advances in lineage-tracing techniques and the ability to profile gene expression in small populations of cells have increased the understanding of how stem cells operate during hair growth and regeneration, the construction of functional follicles with cycling activity is still a great challenge for the hair research field and for translational and clinical applications. Given that hair formation and cycling rely on tightly coordinated epithelial-mesenchymal interactions, we thus review potential cell sources with HF-inducive capacities and summarize current bioengineering strategies for HF regeneration with functional restoration.

Up-regulated lncRNA5322 elevates MAPK1 to enhance proliferation of hair follicle stem cells as a ceRNA of microRNA-19b-3p

Hair follicle stem cells (HFSCs), located in the bulge region of the follicle, maintain hair follicle growth and cycling. Long non-coding RNAs (lncRNAs), non-protein coding transcripts, are widely known to play critical roles in differentiation and proliferation of stem cells. Therefore, the current study aimed to explore the regulatory roles of lncRNA5322 in HFSCs proliferation and the underlying regulatory mechanisms. Initially, the expression patterns of lncRNA5322 and microRNA-19b-3p (miR-19b-3p) in HFSCs were detected. Subsequently, gain-and loss-of-functions analyses were conducted to explore the roles of lncRNA5322, miR-19b-3p and mitogen-activated protein kinase 1 (MAPK1) in cell proliferation, colony formation and apoptosis of HFSCs, with the expression of cyclin-dependent kinase (CDK)1 and CDK2 examined. Also, the interaction relationships among lncRNA5322, miR-19b-3p and MAPK1 were explored. Furthermore, a mouse model was established to detect the roles of lncRNA5322, miR-19b-3p, and MAPK1 in wound contraction and epidermal regeneration. Over-expressed lncRNA5322 was found to promote proliferation, colony formation ability but inhibit apoptosis of HFSCs, in addition to up-regulation of the expression of CDK1 and CDK2. LncRNA5322 was found to act as a ceRNA of miR-19b-3p which directly targeted MAPK1. Furthermore, up-regulation of lncRNA5322 enhanced wound contraction and epidermal regeneration in vivo by increasing the expression of MAPK1 through functioning as a ceRNA of miR-19b-3p. In summary, the results in this study suggested that lncRNA5322 serves as a ceRNA of miR-19b-3p to elevate the expression of MAPK1, ultimately promoting HFSCs proliferation, wound contraction and epidermal regeneration of mouse model.

Melatonin promotes Cashmere goat (Capra hircus) secondary hair follicle growth: a view from integrated analysis of long non-coding and coding RNAs

The role of melatonin in promoting the yield of Cashmere goat wool has been demonstrated for decades though there remains a lack of knowledge regarding melatonin mediated hair follicle growth. Recent studies have demonstrated that long non-coding RNAs (lncRNAs) are widely transcribed in the genome and play ubiquitous roles in regulating biological processes. However, the role of lncRNAs in regulating melatonin mediated hair follicle growth remains unclear. In this study, we established an in vitro Cashmere goat secondary hair follicle culture system, and demonstrated that 500 ng/L melatonin exposure promoted hair follicle fiber growth. Based on long intergenic RNA sequencing, we demonstrated that melatonin promoted hair follicle elongation via regulating genes involved in focal adhesion and extracellular matrix receptor pathways and further cis predicting of lncRNAs targeted genes indicated that melatonin mediated lncRNAs mainly targeted vascular smooth muscle contraction and signaling pathways regulating the pluripotency of stem cells. We proposed that melatonin exposure not only perturbed key signals secreted from hair follicle stem cells to regulate hair follicle development, but also mediated lncRNAs mainly targeted to pathways involved in the microvascular system and extracellular matrix, which constitute the highly orchestrated microenvironment for hair follicle stem cell. Taken together, our findings here provide a profound view of lncRNAs in regulating Cashmere goat hair follicle circadian rhythms and broaden our knowledge on melatonin mediated hair follicle morphological changes.

Nature-derived lignan compound VB-1 exerts hair growth-promoting effects by augmenting Wnt/β-catenin signaling in human dermal papilla cells

Background

Vitexin is a kind of lignan compound which has been shown to possess a variety of pharmacological effects, such as anti-inflammatory, anti-oxidative and anti-cancer activities. However the effect of vitexin on hair regeneration has not been elaborated.

Methods

The proliferation of human dermal papilla cells (hDPCs) was examined by cell counting and continuous cell culture after vitexin compound 1 (VB-1) was treated. The expression of lef1, wnt5a, bmp2, bmp4, alpl and vcan was examined by RT-PCR. The expression of dkk1, tgf-β1, active-β-Catenin, and AXIN2 was examined by RT-PCR or immunoblotting. Hair shaft growth was measured in the absence or presence of VB-1.

Results

We demonstrated that VB-1 significantly promotes the proliferation of hDPCs in a concentration-dependent manner within a certain concentration range. Among the hair growth-related genes investigated, dkk1 was clearly down-regulated in hDPCs treated with VB-1. The increased active β-Catenin and decreased AXIN2 protein levels suggest that VB-1 facilitates Wnt/β-catenin signaling in hDPCs in vitro. The expression of DP signature genes was also upregulated after VB-1 treatment. Our study further indicated that VB-1 promotes human hair follicle (HF) growth by HF organ culture assay.

Discussion

VB-1 may exert hair growth-promoting effects via augmenting Wnt/β-catenin signaling in hDPCs.

Human nail stem cells are retained but hypofunctional during aging

The nail is a continuous skin appendage. Cells located around the nails, which display coordinated homeostatic dynamics and release a flow of stem cells in response to regeneration, have been identified in mice. However, very few studies regarding human nail stem cells exist in the literature. Using specimens isolated from humans, we detected an unreported population of cells within the basal layer of postnatal human nail proximal folds (NPFs) and the nail matrix around the nail root. These cells were multi-expressing and expressed stem cell markers, such as keratin 15 (K15), keratin 14 (K14), keratin 19 (K19), CD29, CD34, and leucine-rich repeat-containing G protein-coupled receptor 6 (Lgr6). These cells were very similar to mouse nail stem cells in terms of cell marker expression and their location within the nail. We also found that the putative nail stem cells maintained their abundance with advancing age, but cell proliferation and nail growth rate were decreased on comparison of young and aged specimens. To summarize, we found a putative population of stem cells in postnatal human nails located at NPFs and the nail matrix. These cells may have potential for cell differentiation and be capable of responding to injury, and were retained, but may be hypofunctional during aging.

Expansion of Hair Follicle Stem Cells Sticking to Isolated Sebaceous Glands to Generate in Vivo Epidermal Structures

Hair follicle stem cells (HFSCs) are considered one of the useful donor cell types for skin regenerative medicine owing to their robust proliferative capacity and multipotency. However, methods for easily and effectively obtaining HFSCs from a limited skin biopsy are still lacking. Here we report a novel approach for obtaining a subpopulation of HFSCs from a small skin sample from the rat tail, which uses the sebaceous glands (SGs) to capture the adjacent HFSCs. By means of organ culture, keratinocytes were expanded from the detached SGs, which also included adherent HFSCs from the hair follicle that could be passaged at the single-cell level. These SG-captured keratinocytes strongly expressed the basal layer markers K14, integrin α6, and p63; the bulge stem cell marker K15; and the upper isthmus stem cell marker Plet1. Furthermore, we reconstituted new epidermis, hair follicles, and SGs from the SG-captured keratinocytes using an easily operated, modified skin reconstitution assay based on silicone gel sheeting. This study suggests that the SGs could be an accessible capturer to harvest the adjacent HFSC subpopulation, particularly when the donor tissue is limited.

Expansion of Hair Follicle Stem Cells Sticking to Isolated Sebaceous Glands to Generate in Vivo Epidermal Structures

Hair follicle stem cells (HFSCs) are considered one of the useful donor cell types for skin regenerative medicine owing to their robust proliferative capacity and multipotency. However, methods for easily and effectively obtaining HFSCs from a limited skin biopsy are still lacking. Here we report a novel approach for obtaining a subpopulation of HFSCs from a small skin sample from the rat tail, which uses the sebaceous glands (SGs) to capture the adjacent HFSCs. By means of organ culture, keratinocytes were expanded from the detached SGs, which also included adherent HFSCs from the hair follicle that could be passaged at the single-cell level. These SG-captured keratinocytes strongly expressed the basal layer markers K14, integrin α6, and p63; the bulge stem cell marker K15; and the upper isthmus stem cell marker Plet1. Furthermore, we reconstituted new epidermis, hair follicles, and SGs from the SG-captured keratinocytes using an easily operated, modified skin reconstitution assay based on silicone gel sheeting. This study suggests that the SGs could be an accessible capturer to harvest the adjacent HFSC subpopulation, particularly when the donor tissue is limited.

Concise Review: Human Dermis as an Autologous Source of Stem Cells for Tissue Engineering and Regenerative Medicine

The exciting potential for regenerating organs from autologous stem cells is on the near horizon, and adult dermis stem cells (DSCs) are particularly appealing because of the ease and relative minimal invasiveness of skin collection. A substantial number of reports have described DSCs and their potential for regenerating tissues from mesenchymal, ectodermal, and endodermal lineages; however, the exact niches of these stem cells in various skin types and their antigenic surface makeup are not yet clearly defined. The multilineage potential of DSCs appears to be similar, despite great variability in isolation and in vitro propagation methods. Despite this great potential, only limited amounts of tissues and clinical applications for organ regeneration have been developed from DSCs. This review summarizes the literature on DSCs regarding their niches and the specific markers they express. The concept of the niches and the differentiation capacity of cells residing in them along particular lineages is discussed. Furthermore, the advantages and disadvantages of widely used methods to demonstrate lineage differentiation are considered. In addition, safety considerations and the most recent advancements in the field of tissue engineering and regeneration using DSCs are discussed. This review concludes with thoughts on how to prospectively approach engineering of tissues and organ regeneration using DSCs. Our expectation is that implementation of the major points highlighted in this review will lead to major advancements in the fields of regenerative medicine and tissue engineering.

SIGNIFICANCE

Autologous dermis-derived stem cells are generating great excitement and efforts in the field of regenerative medicine and tissue engineering. The substantial impact of this review lies in its critical coverage of the available literature and in providing insight regarding niches, characteristics, and isolation methods of stem cells derived from the human dermis. Furthermore, it provides analysis of the current state-of-the-art regenerative approaches using human-derived dermal stem cells, with consideration of current guidelines, to assist translation toward therapeutic use.

Ovine Hair Follicle Stem Cells Derived from Single Vibrissae Reconstitute Haired Skin

Hair follicle stem cells (HFSCs) possess fascinating self-renewal capacity and multipotency, which play important roles in mammalian hair growth and skin wound repair. Although HFSCs from other mammalian species have been obtained, the characteristics of ovine HFSCs, as well as the methods to isolate them have not been well addressed. Here, we report an efficient strategy to obtain multipotent ovine HFSCs. Through microdissection and organ culture, we obtained keratinocytes that grew from the bulge area of vibrissa hair follicles, and even abundant keratinocytes were harvested from a single hair follicle. These bulge-derived keratinocytes are highly positive for Krt15, Krt14, Tp63, Krt19 and Itga6; in addition to their strong proliferation abilities in vitro, these keratinocytes formed new epidermis, hair follicles and sebaceous glands in skin reconstitution experiments, showing that these are HFSCs from the bulge outer root sheath. Taken together, we developed an efficient in vitro system to enrich ovine HFSCs, providing enough HFSCs for the investigations about the ovine hair cycle, aiming to promote wool production in the future.

Exogenous connective tissue growth factor preserves the hair-inductive ability of human dermal papilla cells

Connective tissue growth factor influences human dermal papilla cells' hair inductive ability through several signaling pathways.

Isolation and characterization of multipotent cells from human fetal dermis

We report that cells from human fetal dermis, termed here multipotent fetal dermal cells, can be isolated with high efficiency by using a nonenzymatic, cell outgrowth method. The resulting cell population was consistent with the definition of mesenchymal stromal cells by the International Society for Cellular Therapy. As multipotent fetal dermal cells proliferate extensively, with no loss of multilineage differentiation potential up to passage 25, they may be an ideal source for cell therapy to repair damaged tissues and organs. Multipotent fetal dermal cells were not recognized as targets by T lymphocytes in vitro, thus supporting their feasibility for allogenic transplantation. Moreover, the expansion protocol did not affect the normal phenotype and karyotype of cells. When compared with adult dermal cells, fetal cells displayed several advantages, including a greater cellular yield after isolation, the ability to proliferate longer, and the retention of differentiation potential. Interestingly, multipotent fetal dermal cells expressed the pluripotency marker SSEA4 (90.56 ± 3.15% fetal vs. 10.5 ± 8.5% adult) and coexpressed mesenchymal and epithelial markers (>80% CD90(+)/CK18(+) cells), coexpression lacking in the adult counterparts isolated under the same conditions. Multipotent fetal dermal cells were able to form capillary structures, as well as differentiate into a simple epithelium in vitro, indicating skin regeneration capabilities.

Epidermal development in mammals: key regulators, signals from beneath, and stem cells

Epidermis is one of the best-studied tissues in mammals that contain types of stem cells. Outstanding works in recent years have shed great light on behaviors of different epidermal stem cell populations in the homeostasis and regeneration of the epidermis as well as hair follicles. Also, the molecular mechanisms governing these stem cells are being elucidated, from genetic to epigenetic levels. Compared with the explicit knowledge about adult skin, embryonic development of the epidermis, especially the early period, still needs exploration. Furthermore, stem cells in the embryonic epidermis are largely unstudied or ambiguously depicted. In this review, we will summarize and discuss the process of embryonic epidermal development, with focuses on some key molecular regulators and the role of the sub-epidermal mesenchyme. We will also try to trace adult epidermal stem cell populations back to embryonic development. In addition, we will comment on in vitro derivation of epidermal lineages from ES cells and iPS cells.