Low-level laser treatment promotes skin wound healing by activating hair follicle stem cells in female mice

Identification of lncRNAs involved in the hair follicle cycle transition of cashmere goats in response to photoperiod change

BACKGROUND

Cashmere goats, as one of the important domesticated animal species, are known for their high-quality fiber. The growth of cashmere has seasonal variations caused by photoperiodic changes, but the molecular genetic mechanisms underlying this phenotype including the functional role of long non-coding RNAs (lncRNA) is still poorly understood.

RESULTS

In this study, we analyzed the RNA-seq dataset of 39 Cashmere goat skin samples including all different growth stages and identified 1591 lncRNAs. These lncRNAs exhibited growth stage-specific expression patterns. Combining shortened light and hair follicle growth cycles, we found that 68% of differentially photo-responsive lncRNAs showed similar expression trends during transition phase I (early anagen to anagen phase). This suggests that the mechanism of light-controlled induction of hair follicles from early anagen to anagen is similar to that of transition phase I. According to weighted gene co-expression network analyses (WGCNA) analysis, it was found that two gene clusters and 10 hub lncRNAs participated in the transformation of hair follicle cycle, inducing hair follicles to enter the full growth phase in advance. These hub lncRNAs may regulate the development cycle of hair follicles through cis- or trans-regulation on clock genes, SLC superfamily genes, fibroblast growth factor genes.

CONCLUSIONS

This study identified the key lncRNAs and target genes probably participating in the transformation of hair follicle cycle. This study will help further elucidate the role of lncRNAs in the hair follicle cycle and development.

Autografted hair follicles with dermal papilla removed promote wound repair and regeneration in Bama mini-pigs

Autologous free flap transplantation is the most economical and effective method for clinical treatment of large-area trauma, but the shortage of flap donors prevents widespread use of this method. Hair follicle stem cells have great potential to repair wounds, but wound repair by hair follicle stem cells has not yet met expectations. We used a wound model of Bama mini-pigs and treated the wound with autologous hair follicles or flaps. The wound healing was observed on days 7, 14, and 21 post-surgery and wound healing rates were analyzed using Image J software. Hematoxylin and eosin staining was performed to evaluate re-epithelialization of the wound. Immunofluorescence staining was used to detect the expression of hair follicle stem cell markers (CK15, Sox9) and explore the mechanism of wound repair. This research found that autologous hair follicles can accelerate wound healing. The efficiency of hair follicles in wound repair is related to their structure. Dermal papilla acts as a biological barrier to hair follicle-mediated wound repair. Dermal papilla removal enhances wound healing efficiency, likely by relieving dermal papilla-imposed restrictions on hair follicle stem cell migration. Autologous hair follicles for wound repair has the advantages of minimal damage, simple fabrication, and abundant source, which may be able to replace the flap transplantation as a therapeutic strategy in the future. This study is helpful to elucidate the regulatory mechanism of hair follicles involved in wound repair, and has important academic and clinical value for solving the problem of shortage flap donor.

Modulation of gene expression in skin wound healing by photobiomodulation therapy: A systematic review in vivo studies

BACKGROUND

Wound healing is a multistep process involving coordinated responses of a variety of cell types, cytokines, growth factors, and extracellular matrix (ECM) components leading to the physiological restoration of tissue integrity. Photobiomodulation therapy (PBMT) has been highlighted as an approach to improve the healing process, nonetheless at the molecular level, the effects of PBMT are not entirely understood.

AIM

To systematically review publications that investigated gene expression after PBMT during in vivo skin repair.

METHODS

An electronic search was undertaken in Medline Ovid (Wolters Kluwer), PubMed (National Library of Medicine), Web of Science (Thomson Reuters), Scopus (Elsevier), Embase, and LILACS databases. The search strategy was conducted from the terms: low-level light therapy, gene expression, and wound healing and their synonyms. The databases were consulted in December 2023 and no publication year limit was used.

RESULTS

Eleven studies were included in this review and the expression of 186 genes was evaluated. PBMT modified the expression of several targets genes studied, such as down-regulation of genes related to extracellular matrix proteases (MMP2 and MMP9) and pro-inflammatory cytokines (IL10 and IL6) and up-regulation of DNMT3A and BFGF.

CONCLUSION

This review demonstrates that PBMT is capable of regulating gene expression during wound healing. Most evidence showed a positive impact of PBMT in regulating genes linked to inflammatory cytokines improving skin wound healing. Yet, the effects of PBMT in genes involved in other mechanisms still need to be better understood.

Photobiomodulation Facilitates Rat Cutaneous Wound Healing by Promoting Epidermal Stem Cells and Hair Follicle Stem Cells Proliferation

BACKGROUND

Cutaneous wound healing represents a common fundamental phenomenon requiring the participation of cells of distinct types and a major concern for the public. Evidence has confirmed that photobiomodulation (PBM) using near-infrared (NIR) can promote wound healing, but the  cells involved and the precise molecular mechanisms remain elusive.

METHODS

Full-thickness skin defects with a diameter of 1.0 cm were made on the back of rats and randomly divided into the control group, 10 J, 15 J, and 30 J groups. The wound healing rate at days 4, 8, and 12 postoperatively was measured. HE and Masson staining was conducted to reveal the histological characteristics. Immunofluorescence staining was performed to label the epidermal stem cells (ESCs) and hair follicle stem cells (HFSCs). Western blot was performed to detect the expressions of proteins associated with ESCs and HFSCs. Cutaneous wound tissues were collected for RNA sequencing. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes analysis was performed, and the hub genes were identified using CytoHubba and validated by qRT-PCR.

RESULTS

PBM can promote reepithelialization, extracellular matrix deposition, and wound healing, increase the number of KRT14+/PCNA+ ESCs and KRT15+/PCNA+ HFSCs, and upregulate the protein expression of P63, Krt14, and PCNA. Three hundred and sixty-six differentially expressed genes (DEGs) and 7 hub genes including Sox9, Krt5, Epcam, Cdh1, Cdh3, Dsp, and Pkp3 were identified. These DEGs are enriched in skin development, cell junction, and cadherin binding involved in cell-cell adhesion etc., while these hub genes are related to skin derived stem cells and cell adhesion.

CONCLUSION

PBM accelerates wound healing by enhancing reepithelialization through promoting ESCs and HFSCs proliferation and elevating the expression of genes associated with stem cells and cell adhesion. This may provide a valuable alternative strategy to promote wound healing and reepithelialization by modulating the proliferation of skin derived stem cells and regulating genes related to cell adhesion.

A transient photoactivation of epidermal stem cells by femtosecond laser promotes skin wound healing

Wound healing is a long-term complex process, in which epidermal stem cells (EPSCs) in epidermis of skin have been found to play an essential role in it. We develop a noninvasive method to activate EPSCs in skin in vivo to promote wound healing, based on a microscopic system to enable a sequential frame-by-frame scanning of a femtosecond laser at 800 nm to the predefined skin region for a single time for 16 seconds. The laser is tightly focused on a submicron spot and localized in the epidermis, and scans point by point to activate EPSCs there. The density and stemness of EPSCs are significantly enhanced for at least 60 hours after the single-time transient photoactivation. We demonstrate this method works in a skin wound mouse model. Our results provide an optical method for in vivo EPSC activation and hold good potential in wound healing.

Fullerenol protects cornea from ultraviolet B exposure

The eyes are highly susceptible to the oxidative stress induced by ultraviolet B (UVB, wavelength between 280 ∼ 320 nm), which could cause severe damage to the cornea. Fullerenols are effective antioxidants to alleviate UVB-induced injury, while their application for the eyes is still rare. In present study, we investigated the protective performance and mechanism of fullerenols on cornea under UVB radiation in vivo and in vitro. The synthesized fullerenols exhibited broad-spectrum free radical scavenging properties (applicable to both reactive oxygen species (ROS) and reactive nitrogen species (RNS)) and photo-stability. When compared with another widely used antioxidant glutathione (GSH), the administration of fullerenols markedly decreased the injured area, corneal edema, cell death, and increased the cell proliferation in UVB-induced rat cornea. The effects of fullerenols were confirmed in UVB-exposed human corneal epithelial cells (hCECs), where elevated cell viability and proliferation, decreased oxidative free radical production, repaired mitochondrial dysfunction and DNA lesions were observed. RNA sequencing (RNA-Seq) analysis demonstrated that fullerenol alleviated UVB-induced corneal injury through down-regulation of oxidative stress-related genes and up-regulation of proliferation-associated genes. Our results demonstrate the suitability of fullerenols as a potential exogenous treatment in ameliorating UVB-induced cornea damage.