Hair follicle stem cell proliferation, Akt and Wnt signaling activation in TPA-induced hair regeneration

Revealing Dynamics of Protein Phosphorylation: A Study on the Cashmere Fineness Disparities in Liaoning Cashmere Goats

Exploring the landscape of protein phosphorylation, this investigation focuses on skin samples from LCG (Liaoning Cashmere Goats), characterized by different levels of cashmere fineness. Employing LC-MS/MS technology, we meticulously scrutinized FT-LCG (fine-type Liaoning Cashmere Goats) and CT-LCG (coarse-type Liaoning Cashmere Goats). Identifying 512 modified proteins, encompassing 1368 phosphorylated peptide segments and 1376 quantifiable phosphorylation sites, our exploration further revealed consistent phosphorylation sites in both groups. Analysis of phosphorylated peptides unveiled kinase substrates, prominently featuring Protein Kinase C, Protein Kinase B and MAPK3-MAPK1-MAPK7-NLK-group. Differential analysis spotlighted 28 disparate proteins, comprising six upregulated and twenty-two downregulated. Cluster analysis showcased the robust clustering efficacy of the two sample groups. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analyses underscored the significance of the purine metabolism pathway, suggesting its pivotal role in modulating cashmere fineness in LCG. Notably, through differential protein analysis, two crucial proteins were identified: HSL-X (hormone-sensitive lipase isoform X1) and KPRP (keratinocyte proline-rich protein). Further evidence supports LIPE and KPRP as key genes regulating cashmere fineness, paving the way for promising avenues in further research. These findings not only contribute to a nuanced understanding of protein-level dynamics in cashmere but also provide a theoretical foundation for the selective breeding of superior Liaoning Cashmere Goat strands.

LncRNA RP11-818O24.3 promotes hair-follicle recovery via FGF2-PI3K/Akt signal pathway

A previous study indicated that patients with androgenic alopecia (AGA) have significantly reduced levels of LncRNA RP11-818O24.3. This study investigates whether LncRNA RP11-818O24.3 promotes hair-follicle recovery and its possible mechanism. Hair alteration and cutaneous histopathological changes induced by testosterone propionate were observed by H&E and bromodeoxyuridinc (BrdU) stain to evaluate the therapeutic effect of LncRNA RP11-818O24.3 in C57BL/6 J mice. The cellular viability was analyzed in LncRNA RP11-818O24.3-transfected human hair-follicle stem cells (HFSCs) in vitro. The signaling pathways and pro-proliferative factors were investigated by transcriptomic gene sequencing and qRT-PCR. LncRNA RP11-818O24.3 transfection successfully recovered hair growth and hair-follicle cells in AGA mice. In a series of HFSC studies in vitro, LncRNA RP11-818O24.3 transfection greatly promoted cellular proliferation and decreased cellular apoptosis. Transcriptome gene sequencing suggested that the phosphatidylinositol 3-kinase (PI3K)-Akt pathway was upregulated by LncRNA RP11-818O24.3. The qRT-PCR results showed that fibroblast growth factor (FGF)-2 was 14-times upregulated after LncRNA RP11-818O24.3 transfection. Hair-follicle recovery activity of LncRNA RP11-818O24.3 may involve the upregulation of FGF2 and PI3K-Akt to promote follicle stem cell survival. These data not only provide a theoretical basis for AGA development but also reveal a novel therapeutic method for AGA patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-024-00624-3.

Pilose antler extracts promotes hair growth in androgenetic alopecia mice by activating hair follicle stem cells via the AKT and Wnt pathways

Background: Angrogenetic alopecia (AGA) is one of the most prevalent hair loss disorders worldwide. The hair follicle stem cell (HFSC) is closely related to the formation of hair follicle (HF) structure and HF self-renewal. The activation of HFSC in AGA is critical for hair growth. Pilose antler has been reported to have hair growth-promoting activity, but the mechanism of action on AGA and HFSC has not been reported. Methods: We previously extracted an active component from the pilose antler known as PAEs. In this study, we conducted experiments using AGA mice and HFSC. The effects of PAEs on hair growth in AGA mice were firstly detected, and then the mechanisms of PAEs for AGA were predicted by integrating network pharmacology and de novo transcriptomics data of pilose antler. Finally, biological experiments were used to validate the molecular mechanism of PAEs in treating AGA both in vivo and in vitro. Results: It was found that PAEs promoted hair regrowth by accelerating the activation of anagen, delaying the anagen-catagen transition. It also alleviated the morphological changes, such as hair shortening, thinning, miniaturization, and HF number reduction, and regulated the hair regeneration process of four subtypes of hair. We further found that PAEs could promote the proliferation of HFSC, outer root sheath (ORS) cells, and hair bulb cells in AGA mice. We then integrated network pharmacology and pilose antler transcriptomics data to predict that the mechanism of PAEs treatment in AGA mice is closely related to the PI3K-AKT/Wnt-β-Catenin pathways. Subsequently, it was also verified that PAEs could activate both pathways in the skin of AGA mice. In addition, we found that PAEs perhaps increased the number of blood vessels around dermal papilla (DP) in experiments in vivo. Meanwhile, the PAEs stimulated the HFSC proliferation in vitro and activated the AKT and Wnt pathways. However, the proliferative activity of HFSC was inhibited after blocking the Wnt pathway and AKT activity. Conclusion: This study suggests that the hair growth-promoting effect of PAEs in AGA mice may be closely related to the stimulation of the AKT and Wnt pathways, which in turn activates the proliferation of HFSC.

Metabolomics reveals metabolites associated with hair follicle cycle in cashmere goats

BACKGROUND

The hair follicle is a skin accessory organ that regulates hair development, and its activity varies on a regular basis. However, the significance of metabolites in the hair follicle cycle has long been unknown.

RESULTS

Targeted metabolomics was used in this investigation to reveal the expression patterns of 1903 metabolites in cashmere goat skin during anagen to telogen. A statistical analysis was used to investigate the potential associations between metabolites and the hair follicle cycle. The findings revealed clear changes in the expression patterns of metabolites at various phases and in various feeding models. The majority of metabolites (primarily amino acids, nucleotides, their metabolites, and lipids) showed downregulated expression from anagen (An) to telogen (Tn), which was associated with gene expression, protein synthesis and transport, and cell structure, which reflected, to some extent, that the cells associated with hair follicle development are active in An and apoptotic in An-Tn. It is worth mentioning that the expression of vitamin D3 and 3,3',5-triiodo-L-thyronine decreased and then increased, which may be related to the shorter and longer duration of outdoor light, which may stimulate the hair follicle to transition from An to catagen (Cn). In the comparison of different hair follicle development stages (An, Cn, and Tn) or feeding modes (grazing and barn feeding), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that common differentially expressed metabolites (DEMs) (2'-deoxyadenosine, L-valine, 2'-deoxyuridine, riboflavin, cytidine, deoxyguanosine, L-tryptophan, and guanosine-5'-monophosphate) were enriched in ABC transporters. This finding suggested that this pathway may be involved in the hair follicle cycle. Among these DEMs, riboflavin is absorbed from food, and the expression of riboflavin and sugars (D-glucose and glycogen) in skin tissue under grazing was greater and lower than that during barn feeding, respectively, suggesting that eating patterns may also alter the hair follicle cycle.

CONCLUSIONS

The expression patterns of metabolites such as sugars, lipids, amino acids, and nucleotides in skin tissue affect hair follicle growth, in which 2'-deoxyadenosine, L-valine, 2'-deoxyuridine, riboflavin, cytidine, deoxyguanosine, L-tryptophan, and guanosine-5'-monophosphate may regulate the hair follicle cycle by participating in ABC transporters. Feeding practices may regulate hair follicle cycles by influencing the amount of hormones and vitamins expressed in the skin of cashmere goats.

Recent progress in hair follicle stem cell markers and their regulatory roles

Hair follicle stem cells (HFSCs) in the bulge are a multipotent adult stem cell population. They can periodically give rise to new HFs and even regenerate the epidermis and sebaceous glands during wound healing. An increasing number of biomarkers have been used to isolate, label, and trace HFSCs in recent years. Considering more detailed data from single-cell transcriptomics technology, we mainly focus on the important HFSC molecular markers and their regulatory roles in this review.

Identification of Potential miRNA-mRNA Regulatory Network Associated with Growth and Development of Hair Follicles in Forest Musk Deer

In this study, sRNA libraries and mRNA libraries of HFs of FMD were constructed and sequenced using an Illumina HiSeq 2500, and the expression profiles of miRNAs and genes in the HFs of FMD were obtained at the anagen and catagen stages. In total, 565 differentially expressed unigenes (DEGs) were identified, 90 of which were upregulated and 475 of which were downregulated. In the BP category of GO enrichment, the DEGs were enriched in the processes related to HF development and differentiation, including the hair cycle regulation and processes, HF development, skin epidermis development, regulation of HF development, skin development, the Wnt signaling pathway, and the BMP signaling pathway. Through KEGG analysis it was found that DEGs were significantly enriched in pathways associated with HF development and growth. A total of 186 differentially expressed miRNAs (DEmiRNAs) were screened (p < 0.05) in the HFs of FMD at the anagen stage vs. the catagen stage, 33 of which were upregulated and 153 of which were downregulated. Through DEmiRNA-mRNA association analysis, we found DEmiRNAs and target genes that mainly play regulatory roles in HF development and growth. The enrichment analysis of DEmiRNA target genes revealed similarities with the enrichment results of DEGs associated with HF development. Notably, both sets of genes were enriched in key pathways such as the Notch signaling pathway, melanogenesis, the cAMP signaling pathway, and cGMP-PKG. To validate our findings, we selected 11 DEGs and 11 DEmiRNAs for experimental verification using RT-qPCR. The results of the experimental validation were consistent with the RNA-Seq results.

The Identification and Characteristics of miRNAs Related to Cashmere Fiber Traits in Skin Tissue of Cashmere Goats

microRNAs (miRNAs) are involved in the regulation of biological phenomena by down-regulating the expression of mRNAs. In this study, Liaoning cashmere (LC) goats (n = 6) and Ziwuling black (ZB) goats (n = 6) with different cashmere fiber production performances were selected. We supposed that miRNAs are responsible for the cashmere fiber trait differences. To test the hypothesis, the expression profiles of miRNAs from the skin tissue of the two caprine breeds were compared using small RNA sequencing (RNA-seq). A total of 1293 miRNAs were expressed in the caprine skin samples, including 399 known caprine miRNAs, 691 known species-conserved miRNAs, and 203 novel miRNAs. Compared with ZB goats, 112 up-regulated miRNAs, and 32 down-regulated miRNAs were found in LC goats. The target genes of the differentially expressed miRNAs were remarkably concentrated on some terms and pathways associated with cashmere fiber performance, including binding, cell, cellular protein modification process, and Wnt, Notch, and MAPK signaling pathways. The miRNA-mRNA interaction network found that 14 miRNAs selected may contribute to cashmere fiber traits regulation by targeting functional genes associated with hair follicle activities. The results have reinforced others leading to a solid foundation for further investigation of the influences of individual miRNAs on cashmere fiber traits in cashmere goats.

Melatonin Promotes the Development of Secondary Hair Follicles in Adult Cashmere Goats by Activating the Keap1-Nrf2 Signaling Pathway and Inhibiting the Inflammatory Transcription Factors NFκB and AP-1

Exogenous melatonin (MT) has been used to promote the growth of secondary hair follicles and improve cashmere fiber quality, but the specific cellular-level mechanisms involved are unclear. This study was carried out to investigate the effect of MT on the development of secondary hair follicles and on cashmere fiber quality in cashmere goats. The results showed that MT improved secondary follicle numbers and function as well as enhanced cashmere fiber quality and yield. The MT-treated goat groups had high secondary-to-primary ratios (S:P) for hair follicles, greater in the elderly group (p < 0.05). Antioxidant capacities of secondary hair follicles improved fiber quality and yield in comparison with control groups (p < 0.05/0.01). Levels of reactive oxygen and nitrogen species (ROS, RNS) and malondialdehyde (MDA) were lowered (p < 0.05/0.01) by MT. There was significant upregulation of antioxidant genes (for SOD-3; GPX-1; NFE2L2) and the protein of nuclear factor (Nrf2), and downregulation of the Keap1 protein. There were significant differences in the expression of genes for secretory senescence-associated phenotype (SASP) cytokines (IL-1β, IL-6, MMP-9, MMP-27, CCL-21, CXCL-12, CXCL-14, TIMP-1,2,3) plus their protein of key transcription factors, nuclear factor kappa B (NFκB) and activator protein-1 (AP-1), in comparison with the controls. We concluded that MT could enhance antioxidant capacity and reduce ROS and RNS levels of secondary hair follicles through the Keap1-Nrf2 pathway in adult cashmere goats. Furthermore, MT reduced the expression of the SASP cytokines genes by inhibiting the protein of NFκB and AP-1 in the secondary hair follicles in older cashmere goats, thus delaying skin aging, improving follicle survival, and increasing the number of secondary hair follicles. Collectively, these effects of exogenous MT enhanced the quality and yield of cashmere fibers, especially at 5-7 years old.

A study of combination unilateral subcutaneous botulinum toxin a treatment for androgenetic alopecia

OBJECTIVE

To observe the efficacy of unilateral subcutaneous injection of botulinum toxin A combined with finasteride and minoxidil in the treatment of androgenic alopecia.

METHODS

Thirty-seven patients with androgenic alopecia were treated with finasteride and minoxidil as standard therapy and were randomly assigned to subcutaneous injections of botulinum toxin A in one hemisphere of the head at the beginning of a 6-month treatment. Before treatment, 3 months after treatment, and 6 months after treatment, the patient's head hair growth was photographed and evaluated.

RESULTS

After 3 and 6 months of treatment, hair density of the treated androgenic alopecia patients was higher than before treatment (p < 0.05), and the hair density of the botulinum toxin A injection side was higher than that of the control side (p < 0.05). After 6 months of treatment, the response rate of botulinum toxin A combined with finasteride and minoxidil was 77.5%, with no significant side effects observed.

CONCLUSION

Finasteride and minoxidil have a significant effect on androgenic alopecia, and the effect is further increased after combined with botulinum toxin A subcutaneous injection.

The expanding impact of T-regs in the skin

As the interface between the body and the environment, the skin functions as the physical barrier against external pathogens and toxic agents. In addition, the skin is an immunologically active organ with a plethora of resident adaptive and innate immune cells, as well as effector molecules that provide another layer of protection in the form of an immune barrier. A major subpopulation of these immune cells are the Foxp3 expressing CD4 T cells or regulatory T cells (T-regs). The canonical function of T-regs is to keep other immune cells in check during homeostasis or to dissipate a robust inflammatory response following pathogen clearance or wound healing. Interestingly, recent data has uncovered unconventional roles that vary between different tissues and we will highlight the emerging non-lymphoid functions of cutaneous T-regs. In light of the novel functions of other immune cells that are routinely being discovered in the skin, their regulation by T-regs implies that T-regs have executive control over a broad swath of biological activities in both homeostasis and disease. The blossoming list of non-inflammatory functions, whether direct or indirect, suggests that the role of T-regs in a regenerative organ such as the skin will be a field ripe for discovery for decades to come.

Impaired differentiation potential of CD34-positive cells derived from mouse hair follicles after long-term culture

Hair follicle epithelial stem cells (HFSCs), which exist in the bulge region, have important functions for homeostasis of skin as well as hair follicle morphogenesis. Although several methods for isolation of HFSCs using a variety of stem cell markers have been reported, few investigations regarding culture methods or techniques to yield long-term maintenance of HFSCs in vitro have been conducted. In the present study, we screened different types of commercially available culture medium for culturing HFSCs. Among those tested, one type was shown capable of supporting the expression of stem cell markers in cultured HFSCs. However, both the differentiation potential and in vivo hair follicle-inducing ability of HFSCs serially passaged using that optimal medium were found to be impaired, probably because of altered responsiveness to Wnt signaling. The changes noted in HFSCs subjected to a long-term culture suggested that the Wnt signaling-related environment must be finely controlled for maintenance of the cells.

BMP-AKT-GSK3β signalling restores hair follicle stem cells decrease associated with loss of Sfrp1

Wnt signaling plays a pivotal role in regulating activation, proliferation, stem cell renewal and differentiation of hair follicle stem cells (HFSCs). Secreted frizzled related protein-1 (Sfrp1), a Wnt antagonist is up regulated in the HFSCs; however, its role in the HFSCs regulation is still obscure. Here, we show that Sfrp1 loss showed a depletion of HFSCs, enhanced HFSC proliferation and faster hair follicle cycle at PD21 to PD28, HFSC markers such as Lgr5 and Axin2 were decreased in both the Sfrp1  +/- and Sfrp1  -/- HFSCs. In addition, the second hair follicle cycle was also faster as compared to WT. Importantly, Sfrp1  -/- showed a restoration of HFSC by 2 nd telogen (PD49), while Sfrp1+/- did not show restoration with still having a decreased HFSC. Infact, restoration of HFSCs was due to a pronounced down-regulation of β-CATENIN activity mediated through a cross-talk of BMP-AKT-GSK3β signalling in Sfrp1-/- as compared to Sfrp1+/-, where down regulation was less pronounced. In cultured keratinocytes, Sfrp1 loss resulted in enhanced proliferation and clonogenicity, which were reversed by treating with either BMPR1A or GSK3β inhibitor thereby confirming BMP-AKT-GSK3β signaling involved in β-CATENIN regulation in both the Sfrp1  +/- and Sfrp1  -/- mice. Our study reveals a novel function of Sfrp1 by unravelling an in vivo molecular mechanism that regulate the HFSCs pool mediated through a hitherto unknown cross-talk of BMP-AKT-GSK3β signalling that maintain stem cell pool balance, which in turn maintain skin tissue homeostasis.

Thyroid Hormone Receptor Agonist Promotes Hair Growth in Mice

Background

Thyroxine is important to maintain the normal operation of the body. Both clinical and experimental results show thyroxine is closely related to hair growth, the mechanism of which is not fully understood.

Purpose

Investigate the effect of thyroxine receptor agonist, TDM10842, for dorsal hair growth in C3H mice and explore its underlying mechanism.

Methods

Depilated mice were applied with the TDM10842, vehicle of this drug and without any materials on dorsal skin. RNA-sequencing (RNA-seq) was employed to identify the change in gene expression of skin tissues. Quantitative real-time PCR (rt-PCR) and immunoblotting were conducted to validate key differentially expressed genes (DEGs) between different groups.

Results

The TDM group showed early induction of anagen. 857, 782, and 276 differentially expressed genes were identified between 3 groups. As a critical DEG in group TDM, Pclaf was positively related to the motivation of Wnt/beta-catenin and Hedgehog signaling pathways, with a high expression of Ki67 and cyclinD1.

Conclusion

TDM10842 accelerates the anagen entrance and the potential mechanism might be the activation of Wnt/beta-catenin and Hedgehog pathways. Pclaf serves as a critical molecule involved in pathway activation, and cyclinD1 is an important effector protein downstream of the pathways.

MicroRNA-149-mediated MAPK1/ERK2 Suppression Attenuates Hair Follicle stem Cell Differentiation

Hair follicle stem cells (HFSCs) are responsible for hair growth and hair follicle (HF) regeneration. microRNAs (miRNAs) have been demonstrated to be involved in the differentiation of HFSCs. Thus, present study aimed to explore the potential role of miR-149 in the differentiation of HFSCs. The isolated HFSCs were identified by flow cytometric sorting. miR-149 expression was determined during differentiation of HFSCs. Gain- and loss-of-function approaches were conducted to explore the roles of miR-149, MAPK1/ERK2, and FGF2/c-MYC in colony formation and proliferation of HFSCs. Furthermore, in vivo assays were undertaken in miR-149 knockout mice to confirm their roles in HFSC differentiation. miR-149 was found to be down-regulated during HFSC differentiation, and overexpressed miR-149 restricted the proliferation and differentiation of HFSCs. miR-149 was confirmed to target and inhibit MAPK1/ERK2, which was highly expressed in and positively associated with HFSC differentiation. The MAPK1/ERK2 promotion in HFSC differentiation was achieved by augmenting expression of FGF2 and c-MYC. The in vitro effects of miR-149 were validated in in vivo experiments. Taken together, up-regulated miR-149 restricted HFSC differentiation and hair growth by targeting MAPK1/ERK2 to reduce expression of FGF2 and c-MYC, which sheds light on the underlying molecular mechanism on hair growth.

Integrated Hair Follicle Profiles of microRNAs and mRNAs to Reveal the Pattern Formation of Hu Sheep Lambskin

Hair follicle development is closely associated with wool curvature. Current studies reveal the crucial role of microRNAs (miRNAs) in hair follicle growth and development. However, few studies are known regarding their role in wool curvature. To reveal the potential roles of miRNAs in Hu sheep lambskin with different patterns, a total of 37 differentially expressed (DE) miRNAs were identified in hair follicles between small waves (SM) and straight wool (ST) groups using RNA-seq. Through functional enrichment and miRNA-mRNA co-expression analysis, some key miRNAs (oar-miR-143, oar-miR-200b, oar-miR-10a, oar-miR-181a, oar-miR-10b, oar-miR-125b, etc.) and miRNA-mRNA pairs (miR-125b target CD34, miR-181a target FGF12, LMO3, miR-200b target ZNF536, etc.) were identified. Though direct or indirect ways affecting hair follicle development, these miRNAs and mRNAs may have possible effects on wool curvature, and this study thus provides valuable insight on potential pattern formation.

Dexpanthenol Promotes Cell Growth by Preventing Cell Senescence and Apoptosis in Cultured Human Hair Follicle Cells

Dexpanthenol (D-panthenol) is a precursor of vitamin B5 (pantothenic acid) and is widely used for dietary supplements and topical applications. D-panthenol has long been used in hair care products for the purpose of anti-hair loss, its effects and the underlying mechanisms, however, were barely reported. In this study, the effects of D-panthenol on human hair follicle cells, including dermal papilla cells (hDPCs) and outer root sheath cells (hORSCs), were investigated. D-panthenol enhanced the cell viability, increasing the cellular proliferation marker Ki67 in cultured hDPCs. The markers for apoptosis (Caspase3/9) and cell senescence (p21/p16), reported to be expressed in aged or resting phase follicles, were significantly reduced by D-panthenol. Anagen-inducing factors (ALP; β-catenin; versican), which trigger or elongate the anagen phase, were stimulated by D-panthenol. On the other hand, D-panthenol reduced TGF-β1 expressions in both mRNA and protein levels. The expression of VEGF, which is important for peripheral blood vessel activation; was up-regulated by D-panthenol treatment. In cultured hORSCs, cell proliferation and viability were enhanced, while the mRNA expression of cell senescence markers (p21/p16) was significantly down-regulated. The expressions of both VEGF and its receptor (VEGFR) were up-regulated by D-panthenol. In conclusion, our data suggest that the hair growth stimulating activity of D-panthenol was exerted by increasing the cell viability, suppressing the apoptotic markers, and elongating the anagen phase in hair follicles.

A systematic summary of survival and death signalling during the life of hair follicle stem cells

Hair follicle stem cells (HFSCs) are among the most widely available resources and most frequently approved model systems used for studying adult stem cells. HFSCs are particularly useful because of their self-renewal and differentiation properties. Additionally, the cyclic growth of hair follicles is driven by HFSCs. There are high expectations for the use of HFSCs as favourable systems for studying the molecular mechanisms that contribute to HFSC identification and can be applied to hair loss therapy, such as the activation or regeneration of hair follicles, and to the generation of hair using a tissue-engineering strategy. A variety of molecules are involved in the networks that critically regulate the fate of HFSCs, such as factors in hair follicle growth and development (in the Wnt pathway, Sonic hedgehog pathway, Notch pathway, and BMP pathway), and that suppress apoptotic cues (the apoptosis pathway). Here, we review the life cycle, biomarkers and functions of HFSCs, concluding with a summary of the signalling pathways involved in HFSC fate for promoting better understanding of the pathophysiological changes in the HFSC niche. Importantly, we highlight the potential mechanisms underlying the therapeutic targets involved in pathways associated with the treatment of hair loss and other disorders of skin and hair, including alopecia, skin cancer, skin inflammation, and skin wound healing.

PDGF-BB/SA/Dex injectable hydrogels accelerate BMSC-mediated functional full thickness skin wound repair by promoting angiogenesis

Wound healing is a well-orchestrated dynamic and interactive process, which needs a favorable microenvironment and suitable angiogenesis. Platelet derived growth factor-BB (PDGF-BB) plays a crucial role in wound healing. However, the short half-life of PDGF-BB limits its efficacy. In the present study, we successfully synthesized an injectable hydrogel with sodium alginate (SA) and dextran (Dex) as a delivery system to simultaneously deliver PDGF-BB and bone marrow-derived mesenchymal stem cells (BMSCs) in the wound. Our work demonstrates that the PDGF-BB protein enhanced the survival, migration and endothelial cell (EC) differentiation of BMSCs in vitro. The PDGF-BB/SA/Dex hydrogels could sustainably release PDGF-BB with excellent biocompatibility in vitro and in vivo. Besides, these composite hydrogels loaded with BMSCs could accelerate wound healing by improving epithelialization and collagen deposition. In addition, the PDGF-BB/SA/Dex hydrogels promoted the EC-differentiation of transplanted BMSCs and proliferation of hair follicle stem cells in the wound. Furthermore, the expressions of angiogenesis-specific markers, PDGFR-β, p-PI3K, p-Akt, and p-eNOS, were obviously increased in the PDGF-BB/SA/Dex/BMSCs group. In conclusion, the PDGF-BB/SA/Dex injectable hydrogels could accelerate BMSC-mediated skin wound healing by promoting angiogenesis via the activation of the PDGF-BB/PDGFR-β-mediated PI3K/Akt/eNOS pathway, which may provide a new therapeutic strategy for stem cell therapy in wound healing.

Lgr4 Deletion Delays the Hair Cycle and Inhibits the Activation of Hair Follicle Stem Cells

It is known that LGR4 plays an important role in hair follicle (HF) development, but the impact of LGR4 on the hair cycle is still unclear. In this study, we have found that K14-Cre-mediated skin epithelia-specific deletion of Lgr4 results in delayed anagen entry during the physiological hair cycle and compromised HF regeneration upon transplantation. We show that, although Lgr4 deletion does not appear to affect the number of quiescent HF stem cells, it leads to reduced numbers of LGR5+ and actively proliferating stem cells in the HFs. Moreover, LGR4-deficient HFs show molecular changes consistent with decreased mTOR and Wnt signaling but upregulated BMP signaling. Importantly, the reactivation of the protein kinase B pathway by injecting the protein kinase B activator SC79 in Lgr4-/- mice can effectively reverse the hair cycle delay. Together, these data suggest that LGR4 promotes the normal hair cycle by activating HF stem cells and by influencing the activities of multiple signaling pathways that are known to regulate HF stem cells. Our study also implicates LGR4 as a potential target for treating hair disorder in the future.

miR-203a-3p promotes loureirin A-induced hair follicle stem cells differentiation by targeting Smad1

MicroRNAs (miRNAs) participate in the repair of skin trauma. Our previous study indicated that loureirin A promoted hair follicle stem cells (HFSCs) to repair skin epidermis. However, the mechanism of miRNA-mediated regulation of loureirin A-induced HFSC differentiation remained to be explored. In the present study, HFSCs from rat vibrissa were identified by immunofluorescence in vitro. Microarray and quantitative real time polymerase chain reaction analyses demonstrated that miR-203a-3p was upregulated in differentiated HFSCs induced by loureirin A. The expression of cytoskeletal keratin (CK) 5 and involucrin was promoted by miR-203a-3p mimics while repressed by a miR-203a-3p inhibitor. Smad1 was identified as a key target of miR-203a-3p using target prediction tools. Luciferase reporter gene test confirmed a special target association between miR-203a-3p and Smad1. Short interfering Smad1 was transfected into HFSCs, and the expression levels of CK5 and involucrin were upregulated. Thus, it can be inferred that miR-203a-3p negatively regulated the expression of Smad1 and promoted the differentiation of loureirin A-induced HFSCs. Bone morphogenetic protein (BMP) signal inhibition and Wnt activation coregulate skin injury repair. BMP/Smad1 signaling is involved in maintaining the characteristics of HFSCs and inhibiting their differentiation. Our results showed that miR-203a-3p reduces Smad1 to release BMP inhibition. Taken together, miR-203a-3p/Smad1 is a potential therapeutic molecular target in skin wound healing, and may play an active role in wound repair and regenerative medicine.

Analysis of lncRNAs Expression Profiles in Hair Follicle of Hu Sheep Lambskin

Lambskin of the Hu sheep exhibits high economic value due to its water-wave pattern. Wool curvature is the key factor of the pattern types and quality of lambskin, and it is formed by the interaction between dermal papilla cells and hair matrix cells in the hair follicle, which is regulated by various genes and signaling pathways. Herein, three full-sibling pairs of two-day-old healthy lambs (n = 6) were divided into a straight wool group (ST) and small waves group (SM) with three repetitions. RNA-seq was applied to determine the expression profile of mRNAs and lncRNAs in Hu sheep hair follicles. 25 differentially expressed mRNAs and 75 differentially expressed lncRNAs were found between SM and ST. FGF12, ATP1B4, and TCONS_00279168 were probably associated with hair follicle development. Then, Gene Ontology (GO) and KEGG enrichment analysis were implemented for the functional annotation of target genes of differentially expressed lncRNAs. The results showed that many genes, such as FGF12 and ATP1B4, were found enriched in PI3K-Akt signaling, MAPK signaling, and Ras signaling pathway associated with hair follicle growth and development. In addition, the interaction network of differentially expressed lncRNAs and mRNAs showed that a total of 6 differentially expressed lncRNAs were associated with 12 differentially expressed mRNAs, which may be as candidate mRNAs and lncRNAs. TCONS_00279168 may target ATP1B4 and FGF12 to regulate MAPK, PI3K-Akt, Ras signaling pathways involved in the sheep hair follicle development process. These results will provide the basis for exploring hair follicle development.

The Wnt/β-catenin signaling pathway is involved in regulating feather growth of embryonic chicks

Avian feathers have robust growth and regeneration capability and serve as a useful model for decoding hair morphogenesis and other developmental studies. However, the molecular signaling involved in regulating the development of feather follicles is unclear. The purpose of this study was to investigate the role of the Wnt/β-catenin pathway in regulating feather morphogenesis in embryonic chicks through in ovo injection of different doses of Dickkopf-1 (DKK1, a specific inhibitor of the target of the Wnt/β-catenin pathway). A total of 120 fertilized embryo eggs were randomly divided into 4 treatments, including a noninjection group (control group) and groups injected with 100 μL of phosphate-buffered saline (PBS)/egg (PBS control group), 100 μL of PBS/egg containing 600-ng DKK1/egg (600-ng DKK1 group), and 100-μL PBS/egg containing 1,200-ng DKK1/egg (1,200-ng DKK1 group). Feathers and skin tissues were sampled on embryonic (E) day 15 and the day of hatching to examine the feather mass, diameter and density of feather follicles, and the protein expression of the Wnt/β-catenin pathway. The results showed that, compared with CON and PBS treatment, the injection of DKK1 into the yolk sac of chick embryos had no significant effect on the hatching rate and embryo weight (P > 0.05), while it significantly decreased the relative mass of feathers in the whole body (P < 0.05). The high dose of DKK1 (1,200-ng DKK1/egg) decreased the relative mass of feathers on the back, chest, belly, neck, wings, head, and legs, which was more obvious than that in the 600-ng DKK1 group, which presented a dose-dependent effect. In addition, DKK1 injection significantly downregulated the protein expression levels of β-catenin, transcription factor 4, Cyclin D1, and c-Myc (P < 0.05). The immunofluorescence result of β-catenin was consistent with the Western blotting assay results. Altogether, these observations suggested that the Wnt/β-catenin signaling pathway is involved in regulating feather follicle development and feather growth during the embryonic development of chicks.

Hypertrichotic patches as a mosaic manifestation of Proteus syndrome

BACKGROUND

Proteus syndrome is an overgrowth disorder caused by a mosaic activating AKT1 variant. Hair abnormalities in Proteus syndrome have rarely been reported, and frequencies of such findings have not been elucidated.

OBJECTIVE

To define the types and frequencies of hair findings in individuals with Proteus syndrome.

METHODS

A cross-sectional study was conducted of individuals with clinical features of Proteus syndrome and a confirmed pathogenic variant in AKT1 evaluated between November 1996 and June 2019 at the National Institutes of Health Clinical Center. Medical records were reviewed for patterning, density, and color of hair on the body and scalp.

RESULTS

Of 45 individuals evaluated, 29 (64%) had asymmetric hypertrichosis on the body. This included unilateral blaschkoid hypertrichotic patches overlying normal skin or epidermal nevi in 16 (36%), unilateral nonblaschkoid hypertrichotic patches in 11 (24%), and unilateral limb hypertrichosis in 10 (22%). Diffuse, scattered, or patchy changes in scalp hair density or color were present in 11 individuals (24%).

LIMITATIONS

The retrospective, observational design, and limited longitudinal follow-up.

CONCLUSIONS

Asymmetric variations in hair distribution, thickness, length, and color contribute to the overall mosaic appearance of the skin in Proteus syndrome, an observation that provides novel insights into the role of phosphoinositide 3-kinase (PI3K)-protein kinase B (AKT) signaling in skin appendage development.

Exploration of key regulators driving primary feather follicle induction in goose skin

The primary feather follicles are universal skin appendages widely distributed in the skin of feathered birds. The morphogenesis and development of the primary feather follicles in goose skin remain largely unknown. Here, the induction of primary feather follicles in goose embryonic skin (pre-induction vs induction) was investigated by de novo transcriptome analyses to reveal 409 differentially expressed genes (DEGs). The DEGs were characterized to potentially regulate the de novo formation of feather follicle primordia consisting of placode (4 genes) and dermal condensate (12 genes), and the thickening of epidermis (5 genes) and dermal fibroblasts (17 genes), respectively. Further analyses enriched DEGs into GO terms represented as cell adhesion and KEGG pathways including Wnt and Hedgehog signaling pathways that are highly correlated with cell communication and molecular regulation. Six selected Wnt pathway genes were detected by qPCR with up-regulation in goose skin during the induction of primary feather follicles. The localization of WNT16, SFRP1 and FRZB by in situ hybridization showed weak expression in the primary feather primordia, whereas FZD1, LEF1 and DKK1 were expressed initially in the inter-follicular skin and feather follicle primordia, then mainly restricted in the feather primordia. The spatial-temporal expression patterns indicate that Wnt pathway genes DKK1, FZD1 and LEF1 are the important regulators functioned in the induction of primary feather follicle in goose skin. The dynamic molecular changes and specific gene expression patterns revealed in this report provide the general knowledge of primary feather follicle and skin development in waterfowl, and contribute to further understand the diversity of hair and feather development beyond the mouse and chicken models.

Ginkgolide B and bilobalide promote the growth and increase β-catenin expression in hair follicle dermal papilla cells of American minks

The regeneration of proliferation potential of dermal papilla (DP) cells contributes to the treatment of hair loss disorders. Ginkgolide B (GKB) and bilobalide (BB) are two functional components isolated from Ginkgo biloba that can promote hair growth. In the current study, the effect of GKB or BB on DP cell viability and the related signaling was assessed. Hair follicles were isolated from minks, and the growth of hair follicles was measured under the administration of GKB or BB. DP cells isolated from minks were also subjected to GKB or BB. The administration of GKB or BB induced the growth of hair follicles. The viability of DP cells was also increased by GKB or BB as illustrated by methyl thiazolyl tetrazolium and flow cytometry detection. Moreover, the secretion of VEGF was enhanced by GKB or BB. At molecular level, the activities of Akt, ERK1/2, and β-catenin were induced by GKB, whereas BB only increased the activities of Akt and β-catenin. In conclusion, although the two components influenced the β-catenin signaling activity in distinct mechanisms, they both increased the viability of DP cells and promoted the cycle of hair follicles.

Bay11-7082 facilitates wound healing by antagonizing mechanical injury- and TNF-α-induced expression of MMPs in posterior cruciate ligament

Purposes: To investigate the ability of synoviocytes (SCs) in regulating MMPs expression in the posterior cruciate ligament fibroblasts (PCLfs) after TNF-α treatment, to test whether a specific inflammation inhibitor Bay11-7082 can antagonize the expression of MMPs in PCLfs after injury. Methods: The microenvironment of knee joint cavity after PCL injury was mimicked in an in vitro co-culture system. The effects of TNF-α treatment on the expression of MMPs in PCL fibroblasts (PCLfs) were studied. The expression of MMPs mRNA and protein was detected by qRT-PCR and western blot. For the in vivo study, the Bay11-7082 inhibitor was injected into the knee joint cavity after injury, and then were performed on histological analysis. Results: In the mono-culture conditions, 6% mechanical injury upregulated the expression of MMP-2, whereas downregulated MMP-1 and -3, additionally 12% mechanical injury were upregulated all. However, in co-culture conditions, 6% and 12% both significantly increased MMPs expressions. Stretch injury and TNF-α treatment significantly upregulated expression of MMPs mRNA and protein levels in mono-cultured PCLfs. This effect was more significant in PCLfs Plus SCs co-culture system, in which the cells were treated by combination of stretch injury and TNF-α. In addition, Bay11-7082, a specific inflammation inhibitor, could significantly decrease the expression of MMPs induced by stretch injury and/or TNF-α treatment. Less infiltrated inflammatory cells and more integrated tissues were detected in injury PCL 2 weeks after Bay11-7082 treatment, compared to injury group. Immunofluorescent staining showed very low expression levels of MMPs in PCL of Bay11-7082-treated group, compared to the injury groups. Conclusions: SCs sever as the supporting cells that aggravate the TNF-α-induced MMPs accumulation in PCLfs. Inhibition of the expression of MMPs by Bay11-7082 is a promising way to facilitate the self-healing of PCL.

Ginsenoside Rb1 promotes the growth of mink hair follicle via PI3K/AKT/GSK-3β signaling pathway

AIMS

Hair follicles play a critical role in the process of hair growth. The dermal papilla cells (DPCs) are an important component in the hair follicle regeneration and growth. This study investigated the effects of ginsenoside Rb1 on the growth of cultured mink hair follicles and DPCs.

MAIN METHODS

The mink hair follicles were treated with ginsenoside Rb1 for 9 days and their lengths were measured every three days. Real-time PCR was used to determine the mRNA expression of vascularization endothelial growth factor A (VEGF-A), VEGF receptor 2 (VEGF-R2) and TGF-β1. In addition, the levels of proteins were detected by western blot. Cell proliferation was determined by immunofluorescence staining of proliferation marker Ki-67 and cell cycle analysis was performed on flow cytometry. Moreover, cell migration was evaluated by wound healing assay.

KEY FINDINGS

Ginsenoside Rb1 promoted the growth of hair follicles, and proliferation and migration of DPCs. Ginsenoside Rb1 improved the expression levels of VEGFA and VEGF-R2, while attenuated the TGF-β1 expression both in hair follicles and DPCs. Furthermore, ginsenoside Rb1 facilitated the activation of PI3K/AKT/GSK-3β signaling pathway in hair follicles and DPCs.

SIGNIFICANCE

The results reveals a crucial role of PI3K/AKT/GSK-3β signaling pathway in ginsenoside Rb1-induced growth of hair follicles and DPCs.

Therapeutic Potential of Stem Cells in Follicle Regeneration

Alopecia is caused by a variety of factors which affect the hair cycle and decrease stem cell activity and hair follicle regeneration capability. This process causes lower self-acceptance, which may result in depression and anxiety. However, an early onset of androgenic alopecia is associated with an increased incidence of the metabolic syndrome and an increased risk of the cardiac ischaemic disease. The ubiquity of alopecia provides an encouragement to seek new, more effective therapies aimed at hair follicle regeneration and neoregeneration. We know that stem cells can be used to regenerate hair in several therapeutic strategies: reversing the pathological mechanisms which contribute to hair loss, regeneration of complete hair follicles from their parts, and neogenesis of hair follicles from a stem cell culture with isolated cells or tissue engineering. Hair transplant has become a conventional treatment technique in androgenic alopecia (micrografts). Although an autologous transplant is regarded as the gold standard, its usability is limited, because of both a limited amount of material and a reduced viability of cells obtained in this way. The new therapeutic options are adipose-derived stem cells and stem cells from Wharton's jelly. They seem an ideal cell population for use in regenerative medicine because of the absence of immunogenic properties and their ease of obtainment, multipotential character, ease of differentiating into various cell lines, and considerable potential for angiogenesis. In this article, we presented advantages and limitations of using these types of cells in alopecia treatment.

Potential mechanisms of CD133 in cancer stem cells

Cancer stem cells (CSCs) have emerged as an underlying cause of cancer relapse and resistance to treatment. Initially, biomarkers were used to identify and isolate distinct cell populations. Several CSC markers have been identified from many types of tumors, and these markers are also being used for isolation and enrichment of CSCs. Cluster of differentiation CD133 is a well-characterized CSC marker, and it is involved in tumor cell proliferation, metastasis, tumorigenesis, and recurrence, as well as chemo- and radio-resistance. However, the mechanisms involved in CD133-mediated induction of CSC properties have not yet been elucidated. Here, we introduce and summarize the functions of CD133 in CSCs and suggest new mechanisms that may be of note in our approach to developing novel cancer therapies.