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

Deciphering Early-Stage Molecular Mechanisms of Negative Pressure Wound Therapy in a Murine Model

Negative Pressure Wound Therapy (NPWT) is a commonly employed clinical strategy for wound healing, yet its early-stage mechanisms remain poorly understood. To address this knowledge gap and overcome the limitations of human trials, we establish an NPWT C57BL/6JNarl mouse model to investigate the molecular mechanisms involved in NPWT. In this study, we investigate the intricate molecular mechanisms through which NPWT expedites wound healing. Our focus is on NPWT's modulation of inflammatory immune responses and the concurrent orchestration of multiple signal transduction pathways, resulting in shortened coagulation time and reduced inflammation. Notably, we observe a significant rise in dickkopf-related protein 1 (DKK-1) concentration during NPWT, promoting the differentiation of Hair Follicle Stem Cells (HFSCs) into epidermal cells, expediting wound closure. Under negative pressure, macrophages express and release DKK-1 cytokines, crucial for stimulating HFSC differentiation, as validated in animal experiments and in vitro studies. Our findings illuminate the inflammatory dynamics under NPWT, revealing potential signal transduction pathways. The proposed framework, involving early hemostasis, balanced inflammation, and macrophage-mediated DKK-1 induction, provides a novel perspective on enhancing wound healing during NPWT. Furthermore, these insights lay the groundwork for future pharmacological advancements in managing extensive wounds, opening avenues for targeted therapeutic interventions in wound care.

miR-27a Targeting PIK3R3 Regulates the Proliferation and Apoptosis of Sheep Hair Follicle Stem Cells

Micro RNAs are regulatory factors in tissue development, organ formation, cell growth, apoptosis and other biological processes. In particular, several miRNAs are related to the development of hair follicles. Here, we investigated the effect of the targeting of PIK3R3 by miR-27a on the AKT/MTOR pathway and on the proliferation and apoptosis of hair follicle stem cells (HFSCs) in sheep. Knockdown of the expression of PIK3R3 was found to significantly inhibit the proliferation and promote the apoptosis of HFSCs. Similarly, a miR-27a mimic significantly inhibited the proliferation and promoted the apoptosis of HFSCs. The miR-27a mimic was also shown to significantly inhibit the expression of PIK3R3, AKT, and MTOR and the phosphorylation of AKT and MTOR, while a miR-27a inhibitor increased the expression of these genes. The presence of an miR-27a binding site in the 3' UTR of PIK3R3 was identified by a bioinformatics analysis, and the interaction was verified with a dual-luciferase reporter assay. The expression of PIK3R3 mRNA and protein was negatively correlated with the presence of miR-27a, which suggests that this interaction may be involved in the biological impacts on proliferation and apoptosis. Thus, this study demonstrates that miR-27a plays a potential role in the proliferation and apoptosis of sheep hair follicle stem cells by targeting PIK3R3, which can be used to design new methods to improve sheep wool.

Natural Mycoplasma Infection Reduces Expression of Pro-Inflammatory Cytokines in Response to Ovine Footrot Pathogens

Ovine footrot is a complex multifactorial infectious disease, causing lameness in sheep with major welfare and economic consequences. Dichelobacter nodosus is the main causative bacterium; however, footrot is a polymicrobial disease with Fusobacterium necrophorum, Mycoplasma fermentans and Porphyromonas asaccharolytica also associated. There is limited understanding of the host response involved. The proinflammatory mediators, interleukin (IL)-1β and C-X-C Motif Chemokine Ligand 8 (CXCL8), have been shown to play a role in the early response to D. nodosus in dermal fibroblasts and interdigital skin explant models. To further understand the response of ovine skin to bacterial stimulation, and to build an understanding of the role of the cytokines and chemokines identified, primary ovine interdigital fibroblasts and keratinocytes were isolated, cultured and stimulated. The expression of mRNA and protein release of CXCL8 and IL-1β were measured after stimulation with LPS, D. nodosus or F. necrophorum, which resulted in increased transcript levels of IL-1β and CXCL8 in the M. fermentans-free cells. However, only an increase in the CXCL8 protein release was observed. No IL-1β protein release was detected, despite increases in IL-1β mRNA, suggesting the signal for intracellular pre-IL-1β processing may be lacking when culturing primary cells in isolation. The keratinocytes and fibroblasts naturally infected with M. fermentans showed little response to the LPS, a range of D. nodosus preparations or heat-inactivated F. necrophorum. Primary single cell culture models complement ex vivo organ culture models to study different aspects of the host response to D. nodosus. The ovine keratinocytes and fibroblasts infected with M. fermentans had a reduced response to the experimental bacterial stimulation. However, in the case of footrot where Mycoplasma spp. are associated with diseased feet, this natural infection gives important insights into the impact of multiple pathogens on the host response.

3D skin models in domestic animals

The skin is a passive and active barrier which protects the body from the environment. Its health is essential for the accomplishment of this role. Since several decades, the skin has aroused a strong interest in various fields (for e.g. cell biology, medicine, toxicology, cosmetology, and pharmacology). In contrast to other organs, 3D models were mostly and directly elaborated in humans due to its architectural simplicity and easy accessibility. The development of these models benefited from the societal pressure to reduce animal experiments. In this review, we first describe human and mouse skin structure and the major differences with other mammals and birds. Next, we describe the different 3D human skin models and their main applications. Finally, we review the available models for domestic animals and discuss the current and potential applications.

Standards of induced pluripotent stem cells derived clinical-grade neural stem cells preparation and quality control (2021 China version)

Induced pluripotent stem cells (iPSCs) have become the leading research object in the clinical application of restorative medicine. They are easily generated from diverse cell sources and functionally indistinguishable from embryonic stem cells without the accompanying ethical issues. To date, the use of iPSC-derived neural stem cells and their progeny in the treatment of neurodegenerative and injurious diseases has achieved good results, with great potential in cell drug development. However, because of some unique biological properties and differences from traditional drug production processes, cell drug research and development has many problems that can hinder clinical applications. Given this situation, the Chinese Association of Neurorestoratology (Preparatory) and China Committee of the International Association of Neurorestoratology have organized relevant professional experts to formulate the standard presented here. Overall, the aim was to promote the clinical application of neural stem cells (NSCs) and their further derived neural cells from iPSC sources and promote cell drugs’ production and development. This standard refers to the latest research results, quality evaluation criteria for traditional medicines, and the regulatory framework for cellular treatments. The standard considers general biological properties of cells, including cell morphology, cell cycle, karyotype, and cell viability. The specific biological properties of NSCs, such as cell surface markers and differentiation ability, general drug standards, such as aseptic testing, endotoxins, human virus detection, and cell-related drug standards, such as telomerase activity and tumorigenicity, are also considered. This standard will serve as a reference for physicians and scientists who focus on clinical nervous cell applications and studies related to iPSCs.

A Mouse Model for Studying Stem Cell Effects on Regeneration of Hair Follicle Outer Root Sheaths

Objective

Stem cells hold promise for treating hair loss. Here an in vitro mouse model was developed using outer root sheaths (ORSs) isolated from hair follicles for studying stem cell-mediated dermal papillary regeneration.

Methods

Under sterile conditions, structurally intact ORSs were isolated from hair follicles of 3-day-old Kunming mice and incubated in growth medium. Samples were collected daily for 5 days. Stem cell distribution, proliferation, differentiation, and migration were monitored during regeneration.

Results

Cell proliferation began at the glass membrane periphery then spread gradually toward the membrane center, with the presence of CD34 and CD200 positive stem cells involved in repair initiation. Next, CD34 positive stem cells migrated down the glass membrane, where some participated in ORS formation, while other CD34 cells and CD200 positive cells migrated to hair follicle centers. Within the hair follicle matrix, stem cells divided, grew, differentiated and caused outward expansion of the glass membrane to form a dermal papillary structure containing alpha-smooth muscle actin. Neutrophils attracted to the wound site phagocytosed bacterial and cell debris to protect regenerating tissue from infection.

Conclusion

Isolated hair follicle ORSs can regenerate new dermal papillary structures in vitro. Stem cells and neutrophils play important roles in the regeneration process.

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.

ROCK inhibitor Y-27632 maintains the propagation and characteristics of hair follicle stem cells

Hair follicle stem cells (HFSCs) are an important source for skin tissue engineering studies and clinical applications. Here, we describe a differential enrichment approach to derive HFSCs from hair follicles of vibrissae and ear skin using the Rho-associated protein kinase (ROCK) inhibitor Y-27632. In the presence of Y-27632, primary cultured hair follicle cells grew in clustered colonies surrounded by keratinocyte-like cells and simultaneously expressed three HFSC markers: CD34, K15, and ITGB1. HFSCs cultured in medium containing Y-27632 were presented at a stable ratio of 30.7%, 34.1%, and 32.9% after passages 5, 10, and 15, respectively. By contrast, in medium containing epidermal growth factor, clustered HFSC colonies disappeared after 6 passages and lacked HFSC marker expression. After withdrawal of Y-27632 from the medium, HFSCs rapidly differentiated into keratinocyte-like cells. Furthermore, HFSCs derived with Y-27632 formed spherical clusters in collagen matrix in vitro, differentiated into keratinocytes and adipose cells under in vitro induction conditions, and cooperated with fetal dermal cells to regenerate hair follicles in vivo 6 weeks after their intracutaneous injection into immune-deficient mice. These findings suggest that Y-27632 maintains the self-renewal and stemness characteristics of HFSCs during primary skin tissue culture followed by enrichment passaging and that HFSCs derived with Y-27632 possess the differentiation potentials important for tissue engineering and other clinical applications.

Oral fibropapillomatosis and epidermal hyperplasia of the lip in newborn lambs associated with bovine Deltapapillomavirus

Congenital fibropapillomatosis of the gingiva and oral mucosa and epidermal hyperplasia of the lip are described, for the first time, in two newborn lambs. Expression of the E5 oncoprotein of bovine deltapapillomavirus types 2 (BPV-2) and -13 (BPV-13) was detected in both fibropapillomas and the hyperplastic epidermal cells suggesting the BPV infection was the cause of the proliferative lesions. No DNA sequences of BPV-1 and BPV-14 were detected. Both BPV-2 and BPV-13 DNA were also amplified from peripheral blood mononuclear cells (PBMCs) of the newborn lambs’ dams. The concordance between BPV genotypes detected in the blood of dam and the oral and skin pathological samples of their offspring suggests that a vertical hematogeneous transmission was most likely source of BPV infection. Immunoblotting revealed the presence of E5 dimers allowing the viral protein to be biologically active. E5 dimers bind and activate the platelet derived growth factor β receptor (PDGFβR), a major molecular mechanism contributing to disease. The detection of E5 protein within the proliferating cells therefore adds further evidence that the BPV infection was the cause of the proliferative lesions seen in these lambs. This is the first evidence of vertical transmission of BPVs in sheep resulting in a clinical disease.

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.

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.

VEGF165 induces differentiation of hair follicle stem cells into endothelial cells and plays a role in in vivo angiogenesis

Within the vascular endothelial growth factor (VEGF) family of five subtypes, VEGF165 secreted by endothelial cells has been identified to be the most active and widely distributed factor that plays a vital role in courses of angiogenesis, vascularization and mesenchymal cell differentiation. Hair follicle stem cells (HFSCs) can be harvested from the bulge region of the outer root sheath of the hair follicle and are adult stem cells that have multi-directional differentiation potential. Although the research on differentiation of stem cells (such as fat stem cells and bone marrow mesenchymal stem cells) to the endothelial cells has been extensive, but the various mechanisms and functional forms are unclear. In particular, study on HFSCs' directional differentiation into vascular endothelial cells using VEGF165 has not been reported. In this study, VEGF165 was used as induction factor to induce the differentiation from HFSCs into vascular endothelial cells, and the results showed that Notch signalling pathway might affect the differentiation efficiency of vascular endothelial cells. In addition, the in vivo transplantation experiment provided that HFSCs could promote angiogenesis, and the main function is to accelerate host-derived neovascularization. Therefore, HFSCs could be considered as an ideal cell source for vascular tissue engineering and cell transplantation in the treatment of ischaemic diseases.

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.

Spatiotemporal Expression of p63 in Mouse Epidermal Commitment

The embryonic surface ectoderm is a simple flat epithelium consisting of cells that express the cytokeratins K8/K18. Before stratification, K5/K14 expression substitutes K8/K18 expression, marking the event called epidermal commitment. Previous studies show that the transcription factor p63 plays an essential role in epidermal commitment. However, detailed expression information of p63 during early epidermal development in mice is still unclear. We systematically studied the expression pattern of p63 in mouse epidermal commitment, together with K8 and K5. We show that p63 expression could be detected as early as E8.5 in mouse embryos preceding epidermal commitment. p63 expression first appears near the newly formed somites and the posterior part of the embryo, further expanding to the whole embryonic surface with particular enrichment in the first branchial arches and the limb buds. ΔNp63 is the major class of isoforms expressed in this period. Relative expression intensity of p63 depends on the embryonic position. In summary, there is a sequential and regular expression pattern of K8, p63 and K5 in mouse epidermal commitment. Our study not only contributes to understanding the early events during epidermal development but also provides a basal tool to study the function of p63 in mammals.