Targeting of CXXC5 by a Competing Peptide Stimulates Hair Regrowth and Wound-Induced Hair Neogenesis

Signal integrator function of CXXC5 in Cancer

CXXC type zinc finger protein 5 (CXXC5) is a member of the ZF-CXXC family and plays a pivotal role in signal integration and information transfer within cell signaling network. CXXC5 acts as a regulator in various physiological processes, and abnormalities in its protein structure or function have been linked to multiple pathological processes. In this article, we correspondingly describe the composition of the ZF-CXXC family, emphatically introducing the features of the CXXC5 gene and protein, review the role of CXXC5 in cellular signaling networks, the physiological and pathological processes associated with CXXC5 dysregulation, and particularly focus on the correlation between CXXC5 and cancers. Finally, we summarize the current therapies targeting CXXC5 and their potential applications, and discuss the intriguing findings from current studies, and the opportunities and challenges in future.

Comparative study between fractional CO2 laser alone versus fractional CO2 laser combined with topical dutasteride in treatment of male androgenic alopecia

Androgenic alopecia (AGA) is the most common form of non-scarring hair loss, characterized by marked hair follicle miniaturization. AGA is a challenging skin condition with limited treatment results. Laser light can promote hair growth at specific wavelengths. The efficacy of fractional CO2 laser in scalp AGA treatment was reported in a few studies. We aimed to compare the efficacy of fractional CO2 laser alone versus the combination of fractional CO2 laser with topical dutasteride in the treatment of male AGA. 30 male patients with AGA were enrolled in the study; they were divided into two groups. All patients received three sessions of ablative fractional CO2 laser one month apart on the scalp, where group (I) patients were subjected to laser sessions only, and group (II) patients were subjected to topical dutasteride, first immediately after each session and secondly fifteen days after each session. The evaluation was done according to dermoscopy (DermLite® DL4) and photographic assessment. Patient satisfaction and side effects were reported. According to the global photo assessment, the combination of fractional CO2 laser with topical dutasteride showed a statistically significant improvement compared to the fractional CO2 laser alone group. The combination of fractional CO2 laser with topical dutasteride is more efficient in improving male androgenic alopecia than fractional CO2 laser alone according to the investigator's global assessment. There was a significant improvement in all dermoscopic parameters in both groups.

Materials-based hair follicle engineering: Basic components and recent advances

The hair follicle (HF) is a significant skin appendage whose primary function is to produce the hair shaft. HFs are a non-renewable resource; skin damage or follicle closure may lead to permanent hair loss. Advances in biomaterials and biomedical engineering enable the feasibility of manipulating the HF-associated cell function for follicle reconstruction via rational design. The regeneration of bioengineered HF addresses the issue of limited resources and contributes to advancements in research and applications in hair loss treatment, HF development, and drug screening. Based on these requirements, this review summarizes the basic and recent advances in hair follicle regulation, including four components: acquisition of stem cells, signaling pathways, materials, and engineering methods. Recent studies have focused on efficiently combining these components and reproducing functionality, which would boost fabrication in HF rebuilding ex vivo, thereby eliminating the obstacles of transplantation into animals to promote mature development.

In Vitro and In Vivo Models for the Development of Hair Growth Materials By Regulating the β-Catenin Signaling Pathways

Although hair loss contributes to various social and economic, research methods for material development are currently limited. In this study, we established a research model for developing materials for hair growth through the regulation of β-catenin. We confirmed that 100 nM tegatrabetan (TG), a β-catenin inhibitor, decreased the proliferation of human hair follicle dermal papilla cells (HFDPCs) at 72 h. In addition, TG-induced apoptosis suppressed the phosphorylation of GSK-3β and Akt, translocation of β-catenin from the cytosol to the nucleus, and the expression of cyclin D1. Interestingly, TG significantly increased the G2/M arrest in HFDPCs. Subcutaneous injection of TG suppressed hair growth and the number of hair follicles in C57BL/6 mice. Moreover, TG inhibited the expression of cyclin D1, β-catenin, keratin 14, and Ki67. These results suggest that TG-induced inhibition of hair growth can be a promising model for developing new materials for enhancing β-catenin-mediated hair growth.

Modulating embryonic signaling pathways paves the way for regeneration in wound healing

Epithelial tissues, including the skin, are highly proliferative tissues with the capability to constant renewal and regeneration, a feature that is essential for survival as the skin forms a protective barrier against external insults and water loss. In adult mammalian skin, every injury will lead to a scar. The scar tissue that is produced to seal the wound efficiently is usually rigid and lacks elasticity and the skin's original resilience to external impacts, but also secondary appendages such as hair follicles and sebaceous glands. While it was long thought that hair follicles develop solely during embryogenesis, it is becoming increasingly clear that hair follicles can also regenerate within a wound. The ability of the skin to induce hair neogenesis following injury however declines with age. As fetal and neonatal skin have the remarkable capacity to heal without scarring, the recapitulation of a neonatal state has been a primary target of recent regenerative research. In this review we highlight how modulating dermal signaling or the abundance of specific fibroblast subsets could be utilized to induce de novo hair follicles within the wound bed, and thus to shift wound repair with a scar to scarless regeneration.

Serum Zinc Concentration in Patients with Alopecia Areata

Alopecia areata is an autoimmune non-scarring disease in which the exact mechanism that induces loss of immune privilege is unknown. Zinc is important for DNA stability and repair mechanisms that are essential in maintaining normal hair growth. Zinc deficiency has been investigated as an important factor in many autoimmune diseases, and may have a possible role in the aetiopathogenesis of alopecia areata. This study included 32 patients with severe forms of alopecia areata, and 32 age- and sex-matched healthy controls. When comparing serum zinc levels in these 2 groups, statistically significantly lower zinc concentrations were found in the alopecia areata group (p = 0.017). Detected zinc deficiency was statistically more prevalent in patients with alopecia areata (p = 0.011). Evaluating patients with alopecia areata, a statistically significant negative correlation between serum zinc levels and severity of the disease was found (ρ = 0.006). The results indicate that zinc serum assessment is necessary in patients with alopecia areata. Low serum zinc levels were found to correlate with severity of alopecia areata. Given that most severe forms of alopecia areata are frequently most treatment-resistant, additional randomized control trials examining zinc supplementation are necessary to investigate its potential role in the restoration of hair follicles.

Inhibiting the cytosolic function of CXXC5 accelerates diabetic wound healing by enhancing angiogenesis and skin repair

Diabetic wound healing, including diabetic foot ulcer (DFU), is a serious complication of diabetes. Considering the complexity of DFU development, the identification of a factor that mediates multiple pathogeneses is important for treatment. In this study, we found that CXXC-type zinc finger protein 5 (CXXC5), a negative regulator of the Wnt/β-catenin pathway, was overexpressed with suppression of the Wnt/β-catenin pathway and its target genes involved in wound healing and angiogenesis in the wound tissues of DFU patients and diabetes-induced model mice. KY19334, a small molecule that activates the Wnt/β-catenin pathway by inhibiting the CXXC5-Dvl interaction, accelerated wound healing in diabetic mice. The enhancement of diabetic wound healing could be achieved by restoring the suppressed Wnt/β-catenin signaling and subsequently inducing its target genes. Moreover, KY19334 induced angiogenesis in hindlimb ischemia model mice. Overall, these findings revealed that restorative activation of Wnt/β-catenin signaling by inhibiting the function of cytosolic CXXC5 could be a therapeutic approach for treating DFUs.

KY19382 Accelerates Cutaneous Wound Healing via Activation of the Wnt/β-Catenin Signaling Pathway

The Wnt/β-catenin signaling pathway plays important roles in the multi-phases of wound healing: homeostasis, inflammation, proliferative, and remodeling phases. However, there are no clinically available therapeutic agents targeting the Wnt/β-catenin pathway. In this study, we tested the effect of 5, 6-dichloroindirubin-3'-methoxime (KY19382), a small molecule that activates the Wnt/β-catenin pathway via interference with the function of the negative feedback regulator CXXC5, on cutaneous wound healing. KY19382 significantly enhanced cell migration of human keratinocytes and dermal fibroblasts with increased levels of β-catenin, phalloidin, Keratin 14, proliferating cell nuclear antigen (PCNA), Collagen I, and alpha-smooth muscle actin (α-SMA) by activating the Wnt/β-catenin signaling pathway without causing significant cytotoxicity. In addition, levels of Collagen I, Keratin 14, PCNA, and stem cell markers were significantly increased by KY19382 in a cutaneous murine wound healing model. Moreover, KY19382 treatment accelerated re-epithelialization and neo-epidermis formation with collagen deposition and stem cell activation at an early stage of cutaneous wound healing. Overall, KY19382 accelerates wound healing via activating the Wnt/β-catenin pathway, and may have the potential to be used for the development of a new wound healing agent.

Adhesive Hydrogel Patch-Mediated Combination Drug Therapy Induces Regenerative Wound Healing through Reconstruction of Regenerative Microenvironment

Regenerative wound healing involves the scarless wound healing as observed in fetal skin. Multiple features of regenerative wound healing have been well studied; however, the practical application of pro-regenerative materials to recapitulate the regenerative wound healing in adult skins has not yet been achieved. In this study, the authors identified that their novel pro-regenerative material, pyrogallol-functionalized hyaluronic acid (HA-PG) patches in combination with protein transduction domain-fused Dishevelled (Dvl)-binding motif (PTD-DBM), a peptide inhibiting the CXXC-type zinc finger protein 5 (CXXC5)-Dvl interaction, promoted regenerative wound healing in mice. The HA-PG patches loaded with this competitor peptide and valproic acid (VPA), a glycogen synthase kinase 3β (GSK3β) inhibitor, significantly inhibited scar formation during wound healing. The HA-PG patches with PTD-DBM and/or VPA inhibit the expression of differentiated cell markers such as α-smooth muscle actin (α-SMA) while inducing the expression of stem cell markers such as CD105 and Nestin. Moreover, Collagen III, an important factor for regenerative healing, is critically induced by the HA-PG patches with PTD-DBM and/or VPA, as also seen in VPA-treated Cxxc5-/- mouse fibroblasts. Overall, these findings suggest that the novel regeneration-promoting material can be utilized as a potential therapeutic agent to promote both wound healing and scar attenuation.

Effect of DNA aptamer through blocking of negative regulation of Wnt/β-catenin signaling in human hair follicle dermal papilla cells

BACKGROUND

When Wnt binds to the N-terminal of Frizzled, a conformational change occurs in the C-terminal of Frizzled, which binds to Dishevelled1 (Dvl1), a Wnt signaling component protein. When Dvl1 binds to the C-terminal of Frizzled, the concentration of β-catenin increases and it enters the nucleus to transmit cell proliferation signals. CXXC-type zinc finger protein 5 (CXXC5) binds to the Frizzled binding site of Dvl1 and interferes with Dvl1-Frizzled binding. Therefore, blocking CXXC5-Dvl1 binding may induce Wnt signal transduction.

MATERIALS AND METHODS

We used WD-aptamer, a DNA aptamer that specifically binds to Dvl1 and interferes with CXXC5-Dvl1 interaction. We confirmed the penetration of WD-aptamer into human hair follicle dermal papilla cells (HFDPCs) and measured β-catenin expression following treatment with WD-aptamer in HFDPCs, wherein Wnt signaling was activated by Wnt3a. In addition, MTT assay was performed to investigate the effect of WD-aptamer on cell proliferation.

RESULTS

WD-aptamer penetrated the cell, affected Wnt signaling, and increased β-catenin expression, which plays an important role in signaling. Additionally, WD-aptamer induced HFDPC proliferation.

CONCLUSION

CXXC5-associated negative feedback of Wnt/β-catenin signaling can be regulated by interfering with CXXC5-Dvl1 interaction.

CXXC5 Mediates DHT-Induced Androgenetic Alopecia via PGD2

The number of people suffering from hair loss is increasing, and hair loss occurs not only in older men but also in women and young people. Prostaglandin D₂ (PGD₂) is a well-known alopecia inducer. However, the mechanism by which PGD₂ induces alopecia is poorly understood. In this study, we characterized CXXC5, a negative regulator of the Wnt/β-catenin pathway, as a mediator for hair loss by PGD₂. The hair loss by PGD₂ was restored by Cxxc5 knock-out or treatment of protein transduction domain-Dishevelled binding motif (PTD-DBM), a peptide activating the Wnt/β-catenin pathway via interference with the Dishevelled (Dvl) binding function of CXXC5. In addition, suppression of neogenic hair growth by PGD₂ was also overcome by PTD-DBM treatment or Cxxc5 knock-out as shown by the wound-induced hair neogenesis (WIHN) model. Moreover, we found that CXXC5 also mediates DHT-induced hair loss via PGD₂. DHT-induced hair loss was alleviated by inhibition of both GSK-3β and CXXC5 functions. Overall, CXXC5 mediates the hair loss by the DHT-PGD₂ axis through suppression of Wnt/β-catenin signaling.

Wnt/β-catenin signaling activator restores hair regeneration suppressed by diabetes mellitus

Diabetes mellitus is one of the most prevalent diseases in modern society. Many complicationssuch as hepatic cirrhosis, neuropathy, cardiac infarction, and so on are associated with diabetes. Although a relationship between diabetes and hair loss has been recently reported, the treatment of diabetic hair loss by Wnt/β-catenin activators has not been achieved yet. In this study, we found that the depilation-induced anagen phase was delayed in both db/db mice and high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic mice. In diabetic mice, both hair regrowth and wound-induced hair follicle neogenesis (WIHN) were reduced because of suppression of Wnt/β-catenin signaling and decreased proliferation of hair follicle cells. We identified that KY19382, a small molecule that activates Wnt/β-catenin signaling, restored the capabilities of regrowth and WIHN in diabetic mice. The Wnt/β-catenin signaling activator also increased the length of the human hair follicle which was decreased under high glucose culture conditions. Overall, the diabetic condition reduced both hair regrowth and regeneration with suppression of the Wnt/β-catenin signaling pathway. Consequently, the usage of Wnt/β-catenin signaling activators could be a potential strategy to treat diabetes-induced alopecia patients. [BMB Reports 2022; 55(11): 559-564].

Blockade of CXXC5-dishevelled interaction inhibits adipogenic differentiation, obesity, and insulin resistance in mice

Obesity has become a major risk factor for developing metabolic diseases, including insulin resistance, type 2 diabetes, and hypertension. Growing pieces of evidence indicate that the Wnt/β-catenin signaling pathway plays an important role in adipogenesis and obesity. Activation of the Wnt/β-catenin signaling pathway inhibits adipogenesis by suppressing the differentiation of committed preadipocytes into mature adipocytes. CXXC5 is highly induced with suppression of Wnt/β-catenin signaling in early adipogenic differentiation. In addition, silencing CXXC5 in vitro increased β-catenin and decremented the major adipogenic differentiation markers. KY19334, a small molecule that activates the Wnt/β-catenin pathway via inhibition of CXXC5- Dishevelled (Dvl) protein-protein interaction (PPI), suppressed adipogenic differentiation. Administration of KY19334 ameliorated obesity by 26 ± 1.3% and insulin resistance by 23.45 ± 7.09% and reduced adipocyte hypertrophy by 80.87 ± 5.30% in high-fat diet (HFD)-fed mice. In addition, KY19334 accelerated the browning of adipose tissue and promoted hepatic glucose homeostasis in HFD-fed mice. In conclusion, activation of the Wnt/β-catenin signaling by inhibiting the interaction of CXXC5 and Dvl by small molecule-mediated interference is a potential therapeutic approach for treating obesity and insulin resistance.

Wnt/β-catenin signaling activator restores hair regeneration suppressed by diabetes mellitus

Diabetes mellitus is one of the most prevalent diseases in modern society. Many complicationssuch as hepatic cirrhosis, neuropathy, cardiac infarction, and so on are associated with diabetes. Although a relationship between diabetes and hair loss has been recently reported, the treatment of diabetic hair loss by Wnt/β-catenin activators has not been achieved yet. In this study, we found that the depilation-induced anagen phase was delayed in both db/db mice and high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic mice. In diabetic mice, both hair regrowth and wound-induced hair follicle neogenesis (WIHN) were reduced because of suppression of Wnt/β-catenin signaling and decreased proliferation of hair follicle cells. We identified that KY19382, a small molecule that activates Wnt/β-catenin signaling, restored the capabilities of regrowth and WIHN in diabetic mice. The Wnt/β-catenin signaling activator also increased the length of the human hair follicle which was decreased under high glucose culture conditions. Overall, the diabetic condition reduced both hair regrowth and regeneration with suppression of the Wnt/β-catenin signaling pathway. Consequently, the usage of Wnt/β-catenin signaling activators could be a potential strategy to treat diabetes-induced alopecia patients. [BMB Reports 2022; 55(11): 559-564].

Biomaterial Design Inspired by Regenerative Research Organisms

The efficacy of implanted biomaterials is largely dependent on the response of the host's immune and stromal cells. Severe foreign body response (FBR) can impede the integration of the implant into the host tissue and compromise the intended mechanical and biochemical function. Many features of FBR, including late-stage fibrotic encapsulation of implants, parallel the formation of fibrotic scar tissue after tissue injury. Regenerative organisms like zebrafish and salamanders can avoid fibrosis after injury entirely, but FBR in these research organisms is rarely investigated because their immune competence is much lower than humans. The recent characterization of a regenerative mammal, the spiny mouse (Acomys), has inspired us to take a closer look at cellular regulation in regenerative organisms across the animal kingdom for insights into avoiding FBR in humans. Here, we highlight how major features of regeneration, such as blastema formation, macrophage polarization, and matrix composition, can be modulated across a range of regenerative research organisms to elucidate common features that may be harnessed to minimize FBR. Leveraging a deeper understanding of regenerative biology for biomaterial design may help to reduce FBR and improve device integration and performance.

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

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

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

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

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

Whole blood transcriptome profiling identifies candidate genes associated with alopecia in male giant pandas (Ailuropoda melanoleuca)

Background

The giant panda (Ailuropoda melanoleuca) is a threatened species endemic to China. Alopecia, characterized by thinning and broken hair, mostly occurs in breeding males. Alopecia significantly affects the health and public image of the giant panda and the cause of alopecia is unclear.

Results

Here, we researched gene expression profiles of four alopecia giant pandas and seven healthy giant pandas. All pandas were approximately ten years old and their blood samples collected during the breeding season. A total of 458 up-regulated DEGs and 211 down-regulated DEGs were identified. KEGG pathway enrichment identified that upregulated genes were enriched in the Notch signaling pathway and downregulated genes were enriched in ribosome, oxidative phosphorylation, and thermogenesis pathways. We obtained 28 hair growth-related DEGs, and identified three hub genes NOTCH1, SMAD3, and TGFB1 in PPI analysis. Five hair growth-related signaling pathways were identified with abnormal expression, these were Notch, Wnt, TGF-β, Mapk, and PI3K-Akt. The overexpression of NOTCH1 delays inner root sheath differentiation and results in hair shaft abnormalities. The delayed hair regression was associated with a significant decrease in the expression levels of TGFB1.

Conclusions

Our data confirmed the abnormal expression of several hair-related genes and pathways and identified alopecia candidate genes in the giant panda. Results of this study provide theoretical basis for the establishment of prevention and treatment strategies for giant pandas with alopecia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08501-z.

Approaches for Regenerative Healing of Cutaneous Wound with an Emphasis on Strategies Activating the Wnt/β-Catenin Pathway

Significance: In adult mammals, spontaneous repair of a cutaneous wound occurs slowly and leaves a scar with skin adnexa deficiencies. To accelerate cutaneous wound-healing rates and avoid scar formation, current studies have focused on regenerative therapies. Recent Advances: Emerging therapeutics for regenerative wound healing often focus on the use of growth factors and stem cells. However, these therapeutic approaches have limited routine clinical use due to high costs and technical requirements. Critical Issue: Understanding the molecular mechanisms involved in the signaling pathways for cutaneous wound healing and neogenic synthesis of the skin components is important for identification of novel targets for the development of regenerative wound-healing agents. Future Directions: The Wnt/β-catenin pathway is a well-known key player for enhancement of the overall healing process involving tissue regeneration via crosstalk with other signaling pathways. Strategies that activate the Wnt/β-catenin pathway via modulation of the pathway-controlling regulatory factors could provide effective therapeutic approaches for regenerative wound healing.

May the best wound WIHN: the hallmarks of wound-induced hair neogenesis

The hair follicle is a unique mini organ that undergoes continuous cycles of replenishment. While hair follicle formation was long thought to occur strictly during embryogenesis, it is now becoming increasingly clear that hair follicles can regenerate from the wound bed. Here, we provide an overview of the recent advancements in the field of Wound Induced Hair Neogenesis (WIHN) in mice. We briefly outline the hair follicle morphogenic process and discuss the major features of adult hair follicle regeneration. We examine the role of distinct cell types and review the contribution of specific signaling pathways to the WIHN phenotype. The phenomenon of neogenic hair regeneration provides an important platform, which may offer new insights into mammalian regeneration in the adult setting.

Non-thermal atmospheric pressure plasma activates Wnt/β-catenin signaling in dermal papilla cells

There is an unmet need for novel, non-pharmacological therapeutics to treat alopecia. Recent studies have shown the potential biological benefits of non-thermal atmospheric pressure plasma (NTAPP), including wound healing, angiogenesis, and the proliferation of stem cells. We hypothesized that NTAPP might have a stimulatory effect on hair growth or regeneration. We designed an NTAPP-generating apparatus which is applicable to in vitro and in vivo experiments. The human dermal papilla (DP) cells, isolated fresh hair follicles, and mouse back skin were exposed with the NTAPP. Biological outcomes were measured using RNA-sequencing, RT-PCR, Western blots, and immunostaining. The NTAPP treatment increased the expression levels of Wnt/β-catenin pathway-related genes (AMER3, CCND1, LEF1, and LRG1) and proteins (β-catenin, p-GSK3β, and cyclin D1) in human DP cells. In contrast, inhibitors of Wnt/β-catenin signaling, endo-IWR1 and IWP2, attenuated the levels of cyclin D1, p-GSK3β, and β-catenin proteins induced by NTAPP. Furthermore, we observed that NTAPP induced the activation of β-catenin in DP cells of hair follicles and the mRNA levels of target genes of the β-catenin signaling pathway (CCND1, LEF1, and TCF4). NTAPP-treated mice exhibited markedly increased anagen induction, hair growth, and the protein levels of β-catenin, p-GSK3β, p-AKT, and cyclin D1. NTAPP stimulates hair growth via activation of the Wnt/β-catenin signaling pathway in DP cells. These findings collectively suggest that NTAPP may be a potentially safe and non-pharmacological therapeutic intervention for alopecia.

KY19382, a novel activator of Wnt/β-catenin signalling, promotes hair regrowth and hair follicle neogenesis

Background and Purpose

The promotion of hair regeneration and growth heavily depends on the activation of Wnt/β‐catenin signalling in the hair follicle, including dermal papilla (DP). KY19382, one of the newly synthesized analogues of indirubin‐3′‐monoxime (I3O), was identified as a Wnt/β‐catenin signalling activator via inhibition of the interaction between CXXC‐type zinc finger protein 5 (CXXC5) and dishevelled (Dvl). Given the close relationship between the Wnt/β‐catenin signalling and hair regeneration, we investigated the effect of KY19382 on hair regrowth and hair follicle neogenesis.

Experimental Approach

In vitro hair induction effects of KY19382 were performed in human DP cells. The hair elongation effects of KY19382 were confirmed through the human hair follicle and vibrissa culture system. In vivo hair regeneration abilities of KY19382 were identified in three models: hair regrowth, wound‐induced hair follicle neogenesis (WIHN) and hair patch assays using C57BL/6 mice. The hair regeneration abilities were analysed by immunoblotting, alkaline phosphatase (ALP) and immunohistochemical staining.

Key Results

KY19382 activated Wnt/β‐catenin signalling and elevated expression of ALP and the proliferation marker PCNA in DP cells. KY19382 also increased hair length in ex vivo‐cultured mouse vibrissa and human hair follicles and induced hair regrowth in mice. Moreover, KY19382 significantly promoted the generation of de novo hair follicles as shown by WIHN and hair patch assays.

Conclusion and Implications

These results indicate that KY19382 is a potential therapeutic drug that exhibits effective hair regeneration ability via activation of the Wnt/β‐catenin signalling for alopecia treatments.

The epigenetic regulator RINF (CXXC5) maintains <i>SMAD7</i> expression in human immature erythroid cells and sustains red blood cells expansion

The gene CXXC5, encoding a retinoid-inducible nuclear factor (RINF), is located within a region at 5q31.2 commonly deleted in myelodysplastic syndrome and adult acute myeloid leukemia. RINF may act as an epigenetic regulator and has been proposed as a tumor suppressor in hematopoietic malignancies. However, functional studies in normal hematopoiesis are lacking, and its mechanism of action is unknown. Here, we evaluated the consequences of RINF silencing on cytokine-induced erythroid differentiation of human primary CD34⁺ progenitors. We found that RINF is expressed in immature erythroid cells and that RINF-knockdown accelerated erythropoietin-driven maturation, leading to a significant reduction (~45%) in the number of red blood cells, without affecting cell viability. The phenotype induced by RINF-silencing was dependent on tumor growth factor b (TGFb) and mediated by SMAD7, a TGFb-signaling inhibitor. RINF upregulates SMAD7 expression by direct binding to its promoter and we found a close correlation between RINF and SMAD7 mRNA levels both in CD34⁺ cells isolated from bone marrow of healthy donors and myelodysplastic syndrome patients with del(5q). Importantly, RINF knockdown attenuated SMAD7 expression in primary cells and ectopic SMAD7 expression was sufficient to prevent the RINF knockdown-dependent erythroid phenotype. Finally, RINF silencing affects 5’-hydroxymethylation of human erythroblasts, in agreement with its recently described role as a TET2-anchoring platform in mouse. Collectively, our data bring insight into how the epigenetic factor RINF, as a transcriptional regulator of SMAD7, may fine-tune cell sensitivity to TGFb superfamily cytokines and thus play an important role in both normal and pathological erythropoiesis.

Epidermal Stem Cells in Hair Follicle Cycling and Skin Regeneration: A View From the Perspective of Inflammation

There are many studies devoted to the role of hair follicle stem cells in wound healing as well as in follicle self-restoration. At the same time, the influence of the inflammatory cells on the hair follicle cycling in both injured and intact skin is well established. Immune cells of all wound healing stages, including macrophages, γδT cells, and T regs, may activate epidermal stem cells to provide re-epithelization and wound-induced hair follicle neogenesis. In addition to the ability of epidermal cells to maintain epidermal morphogenesis through differentiation program, they can undergo de-differentiation and acquire stem features under the influence of inflammatory milieu. Simultaneously, a stem cell compartment may undergo re-programming to adopt another fate. The proportion of skin resident immune cells and wound-attracted inflammatory cells (e.g., neutrophils and macrophages) in wound-induced hair follicle anagen and plucking-induced anagen is still under discussion to date. Experimental data suggesting the role of reactive oxygen species and prostaglandins, which are uncharacteristic of the intact skin, in the hair follicle cycling indicates the role of neutrophils in injury-induced conditions. In this review, we discuss some of the hair follicles stem cell activities, such as wound-induced hair follicle neogenesis, hair follicle cycling, and re-epithelization, through the prism of inflammation. The plasticity of epidermal stem cells under the influence of inflammatory microenvironment is considered. The relationship between inflammation, scarring, and follicle neogenesis as an indicator of complete wound healing is also highlighted. Taking into consideration the available data, we also conclude that there may exist a presumptive interlink between the stem cell activation, inflammation and the components of programmed cell death pathways.

CXXC5 as an unmethylated CpG dinucleotide binding protein contributes to estrogen-mediated cellular proliferation

Evidence suggests that the CXXC type zinc finger (ZF-CXXC) protein 5 (CXXC5) is a critical regulator/integrator of various signaling pathways that include the estrogen (E2)-estrogen receptor α (ERα). Due to its ZF-CXXC domain, CXXC5 is considered to be a member of the ZF-CXXC family, which binds to unmethylated CpG dinucleotides of DNA and through enzymatic activities for DNA methylation and/or chromatin modifications generates a chromatin state critical for gene expressions. Structural/functional features of CXXC5 remain largely unknown. CXXC5, suggested as transcription and/or epigenetic factor, participates in cellular proliferation, differentiation, and death. To explore the role of CXXC5 in E2-ERα mediated cellular events, we verified by generating a recombinant protein that CXXC5 is indeed an unmethylated CpG binder. We uncovered that CXXC5, although lacks a transcription activation/repression function, participates in E2-driven cellular proliferation by modulating the expression of distinct and mutual genes also regulated by E2. Furthermore, we found that the overexpression of CXXC5, which correlates with mRNA and protein levels of ERα, associates with poor prognosis in ER-positive breast cancer patients. Thus, CXXC5 as an unmethylated CpG binder contributes to E2-mediated gene expressions that result in the regulation of cellular proliferation and may contribute to ER-positive breast cancer progression.

[Wound-induced hair follicle neogenesis: a new perspective on hair follicles regeneration in adult mammals]

OBJECTIVE

To explore the research progress of the cell sources and related signaling pathways of the wound-induced hair follicle neogenesis (WIHN) in recent years.

METHODS

The literature related to WIHN in recent years was reviewed, and the cell sources and molecular mechanism were summarized and discussed.

RESULTS

Current research shows that WIHN is a rare regeneration phenomenon in the skin of adult mammals, with multiple cell origins, both hair follicle stem cells and epithelial stem cells around the wound. Its molecular mechanism is complicated, which is regulated by many signaling pathways. Besides, the process is closely related to the immune response, the immunocytes and their related cytokines provide suitable conditions for this process.

CONCLUSION

There are still many unsolved problems on the cellular origins and molecular mechanisms of the WIHN. Further study on the mechanisms will enhance the understanding of adult mammals' hair follicle regeneration and may provide new strategy for functional healing of the human skin.

Scars or Regeneration?-Dermal Fibroblasts as Drivers of Diverse Skin Wound Responses

Scarring and regeneration are two physiologically opposite endpoints to skin injuries, with mammals, including humans, typically healing wounds with fibrotic scars. We aim to provide an updated review on fibroblast heterogeneity as determinants of the scarring-regeneration continuum. We discuss fibroblast-centric mechanisms that dictate scarring-regeneration continua with a focus on intercellular and cell-matrix adhesion. Improved understanding of fibroblast lineage-specific mechanisms and how they determine scar severity will ultimately allow for the development of antiscarring therapies and the promotion of tissue regeneration.

Through the lens of hair follicle neogenesis, a new focus on mechanisms of skin regeneration after wounding

Wound-induced hair follicle neogenesis (WIHN) is a phenomenon that occurs in adult mammalian skin, where fully functional hair follicles are regenerated in the center of large full-thickness excisional wounds. Although originally discovered over 50 years ago in mice and rabbits, within the last decade it has received renewed interest, as the molecular mechanism has begun to be defined. This de novo regeneration of hair follicles largely recapitulates embryonic hair development, requiring canonical Wnt signaling in the epidermis, however, important differences between the two are beginning to come to light. TLR3 mediated double stranded RNA sensing is critical for the regeneration, activating retinoic acid signaling following wounding. Inflammatory cells, including Fgf9-producing γ-δ T cells and macrophages, are also emerging as important mediators of WIHN. Additionally, while dispensable in embryonic hair follicle development, Shh signaling plays a major role in WIHN and may be able to redirect cells fated to scarring wounds into a regenerative phenotype. The cellular basis of WIHN is also becoming clearer, with increasing evidence suggesting an incredible level of cellular plasticity. Multiple stem cell populations, along with lineage switching of differentiated cells all contribute towards the regeneration present in WIHN. Further study of WIHN will uncover key steps in mammalian development and regeneration, potentially leading to new clinical treatments for hair-related disorders or fibrotic scarring.

Androgenetic alopecia: combing the hair follicle signaling pathways for new therapeutic targets and more effective treatment options

Introduction: In the past 30 years, only two drugs have received FDA approval for the treatment of androgenetic alopecia reflecting a lack of success in unraveling novel targets for pharmacological intervention. However, as our knowledge of hair biology improves, new signaling pathways and organogenesis processes are being uncovered which have the potential to yield more effective therapeutic modalities. Areas covered: This review focuses on potential targets for drug development to treat hair loss. The physiological processes underlying the promise of regenerative medicine to recreate new functional hair follicles in bald scalp are also examined. Expert opinion: The discovery of promising new targets may soon enable treatment options that modulate the hair cycle to preserve or extend the growth phase of the hair follicle. These new targets could also be leveraged to stimulate progenitor cells and morphogenic pathways to reactivate miniaturized follicles in bald scalp or to harness the potential of wound healing and embryogenic development as an emerging paradigm to generate new hair follicles in barren skin.

CXXC5 Mediates P. gingivalis-suppressed Cementoblast Functions Partially via MAPK Signaling Network

Porphyromonas (P.) gingivalis associates tightly with periodontal diseases and it is also a dominant pathogen of periapical periodontitis. However, the influence of P. gingivalis on cementoblasts, root surface cells pivotal in the apical areas, and the possible involvement of other molecules remain largely elusive. CXXC5 is a nuclear protein that regulates gene expression as well as cell growth, differentiation, and apoptosis. In this study, P. gingivalis repressed the mineralization capacity of cementoblasts by inducing inflammatory reactions and inhibiting cell differentiation. Intriguingly, the expression of CXXC5 decreased in P. gingivalis-treated OCCM-30 cells and apical periodontitis models but gradually increased during mineralization. Furthermore, RNA interference of CXXC5 significantly inhibited cementoblast differentiation, represented by decline of bone-associated markers Osterix, osteocalcin (OCN), and alkaline phosphatase (ALP). CXXC5 overexpression facilitated differentiation, and therefore attenuated the P. gingivalis-repressed effects on OCCM-30 cells. In addition, Erk1/2, p38, and PI3K-Akt were inactivated by silencing CXXC5 and activated upon its overexpression, whereas Wnt/β-catenin exhibited an opposite trend. The employment of specific inhibitors revealed that the CXXC5-dependent promotions of cementoblast differentiation were partially abrogated by p38 and PI3K-Akt inhibitors but were exacerbated by inhibiting Erk1/2. Overall, our experiment demonstrated a novel function of CXXC5 in the regeneration of impaired cementum caused by P. gingivalis invasion and suggested that MAPK signaling network balances the facilitation effects of CXXC5 in cementoblast differentiation.

CXXC5 mediates growth plate senescence and is a target for enhancement of longitudinal bone growth

Longitudinal bone growth ceases with growth plate senescence during puberty. However, the molecular mechanisms of this phenomenon are largely unexplored. Here, we examined Wnt-responsive genes before and after growth plate senescence and found that CXXC finger protein 5 (CXXC5), a negative regulator of the Wnt/β-catenin pathway, was gradually elevated with reduction of Wnt/β-catenin signaling during senescent changes of rodent growth plate. Cxxc5 ^-/- mice demonstrated delayed growth plate senescence and tibial elongation. As CXXC5 functions by interacting with dishevelled (DVL), we sought to identify small molecules capable of disrupting this interaction. In vitro screening assay monitoring CXXC5-DVL interaction revealed that several indirubin analogs were effective antagonists of this interaction. A functionally improved indirubin derivative, KY19382, elongated tibial length through delayed senescence and further activation of the growth plate in adolescent mice. Collectively, our findings reveal an important role for CXXC5 as a suppressor of longitudinal bone growth involving growth plate activity.

SDF‑1/CXCR4 induces epithelial‑mesenchymal transition through activation of the Wnt/β‑catenin signaling pathway in rat chronic allograft nephropathy

Epithelial-mesenchymal transition (EMT) has been demonstrated to serve a crucial role in the progression of interstitial fibrosis, which is one of the principal pathological features of chronic allograft nephropathy (CAN). However, to the best of our knowledge, the mechanisms of EMT in CAN have not been investigated. In the present study, the effect of stromal cell-derived factor 1 (SDF-1) and the Wnt signaling pathway on the progression of EMT following kidney transplantation was investigated. The CAN model was established using Fisher 344 and Lewis rats, treated with low-dose cyclosporine with or without AMD3100. CAN was confirmed by the pathological alterations and chronic allograft damage index scoring, and EMT was confirmed by western blotting and reverse transcription-quantitative polymerase chain reaction. In the AMD3100 group, there were lower expression levels of α-SMA and higher expression levels of E-cadherin, which indicated that CAN and EMT were ameliorated by AMD3100. The kidney tissue was analyzed using an mRNA + long noncoding (lnc)RNA microarray. A total of 506 mRNAs and 404 lncRNAs were demonstrated to be significantly differentially expressed between the two groups, which revealed the involvement of SDF-1/CXC chemokine receptor 4 (CXCR4) and the Wnt pathway. SDF-1 was demonstrated to induce EMT in vitro through the upregulation of α-SMA, downregulation of E-cadherin and the wound healing assay, and in the rat renal tubular epithelial cells via the nuclear accumulation of β-catenin, which were all inhibited by either AMD3100 or DKK-1. CXXC finger protein 5 (CXXC5), a negative regulator of the Wnt pathway, was downregulated following treatment with SDF-1, which was inhibited by AMD3100 but not by DKK-1. Thus, CXXC5 may be a regulator downstream of SDF-1/CXCR4 in EMT. In conclusion, SDF-1/CXCR4 induces EMT of renal tubular epithelial cells with the involvement of the Wnt pathway, which may be a novel mechanism and therapeutic target in kidney allograft fibrosis of rats.

Single-cell analysis reveals fibroblast heterogeneity and myeloid-derived adipocyte progenitors in murine skin wounds

During wound healing in adult mouse skin, hair follicles and then adipocytes regenerate. Adipocytes regenerate from myofibroblasts, a specialized contractile wound fibroblast. Here we study wound fibroblast diversity using single-cell RNA-sequencing. On analysis, wound fibroblasts group into twelve clusters. Pseudotime and RNA velocity analyses reveal that some clusters likely represent consecutive differentiation states toward a contractile phenotype, while others appear to represent distinct fibroblast lineages. One subset of fibroblasts expresses hematopoietic markers, suggesting their myeloid origin. We validate this finding using single-cell western blot and single-cell RNA-sequencing on genetically labeled myofibroblasts. Using bone marrow transplantation and Cre recombinase-based lineage tracing experiments, we rule out cell fusion events and confirm that hematopoietic lineage cells give rise to a subset of myofibroblasts and rare regenerated adipocytes. In conclusion, our study reveals that wounding induces a high degree of heterogeneity among fibroblasts and recruits highly plastic myeloid cells that contribute to adipocyte regeneration.

The diversity of fibroblasts contributing to wound healing is unclear. Here, the authors use single-cell RNA-sequencing to identify heterogeneity among murine fibroblasts in the wound and find that recruited myeloid cells contribute to adipocyte regeneration during healing.

Insights into the regeneration of skin from Acomys, the spiny mouse

Members of the Acomys genus, known as spiny mice, are unique among mammals in being perfectly capable of regenerating large areas of skin that have been removed. During this regenerative process hairs, sebaceous glands, erector pili muscles, adipocytes and the panniculus carnosus all regenerate and the dermis does not scar. We review here the processes that the epidermis and the individual components of the dermis undergo during spiny mouse regeneration as well as the molecules that have been identified as potentially important in regeneration. We then relate this to what has been proposed as playing a role in studies from the laboratory mouse, Mus musculus. Differences in the immune systems of spiny mice and laboratory mice are also highlighted as this is suggested to play a part not only in the perfect wound healing that embryos display but also in regeneration in lower vertebrates.

CXXC5: A novel regulator and coordinator of TGF-β, BMP and Wnt signaling

CXXC5 is a member of the CXXC-type zinc-finger protein family. Proteins in this family play a pivotal role in epigenetic regulation by binding to unmethylated CpG islands in gene promoters through their characteristic CXXC domain. CXXC5 is a short protein (322 amino acids in length) that does not have any catalytic domain, but is able to bind to DNA and act as a transcription factor and epigenetic factor through protein-protein interactions. Intriguingly, increasing evidence indicates that expression of the CXXC5 gene is controlled by multiple signaling pathways and a variety of transcription factors, positioning CXXC5 as an important signal integrator. In addition, CXXC5 is capable of regulating various signal transduction processes, including the TGF-β, Wnt and ATM-p53 pathways, thereby acting as a novel and crucial signaling coordinator. CXXC5 plays an important role in embryonic development and adult tissue homeostasis by regulating cell proliferation, differentiation and apoptosis. In keeping with these functions, aberrant expression or altered activity of CXXC5 has been shown to be involved in several human diseases including tumourigenesis. This review summarizes the current understanding of CXXC5 as a transcription factor and signaling regulator and coordinator.

Safety concerns when using novel medications to treat alopecia

INTRODUCTION

Alopecia is often a cause of great concern to patients for cosmetic and psychologic reasons. The aim of treating non-scarring alopecias is to reduce hair loss and, to some extent, enhance hair regrowth. However, therapies for scarring alopecias are limited and aiming to halt disease progression. Nonetheless, available modalities of treatment come with numerous side effects. Areas covered: Many new treatments for non-scarring alopecias have been introduced in recent years. This review summarizes the safety concerns when using novel therapeutic modalities such as JAK inhibitors, hair transplantation, mesotherapy, oral minoxidil, platelet-rich plasma, microneedling, and 5α-reductase inhibitors for treating hair loss. A broad literature search was performed using PubMed and Google Scholar in April 2018 to compile published articles that reported the adverse effects of new therapeutic modalities for alopecia. Expert opinion: Although emerging therapeutic modalities for alopecia have demonstrated efficacy in hair regrowth and treating established disease, their safety profiles vary widely. When considering the new treatments for alopecia, physicians should weigh the potential benefits and risks of each treatment or combination treatment to ensure safe and successful outcomes.

Review of Hair Follicle Dermal Papilla cells as in vitro screening model for hair growth

Hair disorders such as hair loss (alopecia) and androgen dependent, excessive hair growth (hirsutism, hypertrichosis) may impact the social and psychological well-being of an individual. Recent advances in understanding the biology of hair have accelerated the research and development of novel therapeutic and cosmetic hair growth agents. Preclinical models aid in dermocosmetic efficacy testing and claim substantiation of hair growth modulators. The in vitro models to investigate hair growth utilize the hair follicle Dermal Papilla cells (DPCs), specialized mesenchymal cells located at the base of hair follicle that play essential roles in hair follicular morphogenesis and postnatal hair growth cycles. In this review, we have compiled and discussed the extensively reported literature citing DPCs as in vitro model to study hair growth promoting and inhibitory effects. A variety of agents such as herbal and natural extracts, growth factors and cytokines, platelet-rich plasma, placental extract, stem cells and conditioned medium, peptides, hormones, lipid-nanocarrier, light, electrical and electromagnetic field stimulation, androgens and their analogs, stress-serum and chemotherapeutic agents etc. have been examined for their hair growth modulating effects in DPCs. Effects on DPCs' activity were determined from untreated (basal) or stress induced levels. Cell proliferation, apoptosis and secretion of growth factors were included as primary end-point markers. Effects on a wide range of biomolecules and mechanistic pathways that play key role in the biology of hair growth were also investigated. This consolidated and comprehensive review summarizes the up-to-date information and understanding regarding DPCs based screening models for hair growth and may be helpful for researchers to select the appropriate assay system and biomarkers. This review highlights the pivotal role of DPCs in the forefront of hair research as screening platforms by providing insights into mechanistic action at cellular level, which may further direct the development of novel hair growth modulators.

Embryonic-like regenerative phenomenon: wound-induced hair follicle neogenesis

Wound-induced hair follicle neogenesis (WIHN) is a regenerative phenomenon that occurs widely in the skin of adult mammalians. A fully functional follicle can regenerate in the center of a full-thickness wound with a large enough size. The cellular origin of this process is similar to embryonic process. Many growth and development-related pathways are involved in WIHN. Studying WIHN can deeply explore the mechanism of biological growth, development and regeneration, and can identify new treatments for hair-related disorders. Our review aims to enlighten future study by summarizing the clinical manifestation of WIHN, as well as the cellular and molecular mechanism of WIHN in recent studies.

Wound Regeneration Deficit in Rats Correlates with Low Morphogenetic Potential and Distinct Transcriptome Profile of Epidermis

Large excisional wounds in mice prominently regenerate new hair follicles (HFs) and fat, yet humans are deficient for this regenerative behavior. Currently, wound-induced regeneration remains a clinically desirable, but only partially understood phenomenon. We show that large excisional wounds in rats across seven strains fail to regenerate new HFs. We compared wound transcriptomes between mice and rats at the time of scab detachment, which coincides with the onset of HF regeneration in mice. In both species, wound dermis and epidermis share core dermal and epidermal transcriptional programs, respectively, yet prominent interspecies differences exist. Compared with mice, rat epidermis expresses distinct transcriptional and epigenetic factors, markers of epidermal repair, hyperplasia, and inflammation, and lower levels of WNT signaling effectors and regulators. When recombined on the surface of excisional wounds with vibrissa dermal papillae, partial-thickness skin grafts containing distal pelage HF segments, but not interfollicular epidermis, readily regenerated new vibrissa-like HFs. Together, our findings establish rats as a nonregenerating rodent model for excisional wound healing and suggest that low epidermal competence and associated transcriptional profile may contribute to its regenerative deficiency. Future comparison between rat and mouse may lend further insight into the mechanism of wounding-induced regeneration and causes for its deficit.

The Negative Regulator CXXC5: Making WNT Look a Little Less Dishevelled

Wingless-related integration site (WNT)/β-catenin signaling regulates diverse physiological functions including tissue regeneration. Activation of WNT signaling can be inhibited by various agents. Lee et al. investigate the interaction of CXXC-type zinc finger protein 5 (CXXC5) with Dishevelled as one such negative regulator of WNT in hair follicle regeneration.