Dorsal Skin Research Articles

Effects of EGFR-TKI on epidermal melanin unit integrity: Therapeutic implications for hypopigmented skin disorders.

Epidermal melanin unit integrity is crucial for skin homeostasis and pigmentation. Epidermal growth factor (EGF) receptor (EGFR) is a pivotal player in cell growth, wound healing, and maintaining skin homeostasis. However, its influence on skin pigmentation is relatively unexplored. This study investigates the impact and underlying mechanisms of EGFR inhibitors on skin pigmentation. We evaluated EGF and EGFR expression in various skin cells using quantitative real-time PCR, Western blot, and immunofluorescence. EGF and EGFR were predominantly expressed in epidermal keratinocytes, and treatment with the EGFR tyrosine kinase inhibitors (EGFR-TKIs) gefitinib and PD153035 significantly increased stem cell factor (SCF) and endothelin-1 (ET-1) expression in cultured keratinocytes. Enhanced melanocyte migration and proliferation were observed in co-culture, as evidenced by time-lapse live imaging and single-cell tracking assays. Furthermore, topical application of gefitinib to guinea pig dorsal skin induced increased pigmentation and demonstrated efficacy in mitigating rhododendrol-induced leukoderma. Suppression of EGF signaling indirectly enhanced skin pigmentation by upregulating SCF and ET-1 in epidermal keratinocytes. This novel mechanism highlights the pivotal role of EGF signaling in regulating skin pigmentation, and topical EGFR-TKI therapy at an appropriate dose may be a promising approach for depigmentation disorder management.

Qingxiong Ointment and Its Active Ingredient, Shikonin Treat Psoriasis through HIF-1 Signaling Pathway.

Psoriasis is a common chronic inflammatory skin disorder. Qingxiong ointment (QX) is a natural medicinal combination frequently employed in clinical treatment of psoriasis. However, the active ingredients of QX and its precise mechanisms of improving psoriasis remain unclear. This study elucidated the effects of QX on an Imiquimod (IMQ)-induced mouse model of psoriasis while also exploring the regulation of the active ingredient of QX, shikonin, on the HIF-1 signaling pathway in HaCaT cells. A mouse model of psoriasis was established through topical application of IMQ, and the local therapeutic effect of QX was evaluated using dorsal skin tissue with mouse psoriatic lesion and Psoriasis Area Severity Index (PASI) scores, hematoxylin-eosin (HE) staining, and immunohistochemical staining. Elisa and qPCR were employed to identify changes in the expression of inflammation-related factors in the mouse dorsal skin. Immunofluorescence was used to assess changes in the expression of T cell subsets before and after treatment with various doses of QX. HPLC was used to analyze the content of shikonin, and network pharmacology was employed to analyze the main targets of shikonin. Immunofluorescence was used to identify the effects of shikonin on the HIF-1 signaling pathway in IL6-induced psoriasis HaCaT cells. Finally, qPCR was used to identify the differential expression of the HIF-1 signaling pathway in skin tissues. QX significantly reduces PASI scores on the backs of IMQ-induced psoriasis mice. HE staining reveals alleviated epidermal thickness in the QX group. Immunohistochemical analysis shows a significant reduction in ICAM, KI67, and IL17 expression levels in the QX group. Immunofluorescence results indicate that QX can notably decrease the proportions of CD4+ T cells, γδ T cells, and CD8+ T cells while increasing the proportion of Treg cells. Network pharmacology analysis demonstrates that the main targets of shikonin are concentrated in the HIF-1 signaling pathway. Molecular docking results show favorable binding affinity between shikonin and key genes of the HIF-1 signaling pathway. Immunofluorescence results reveal that shikonin significantly reduces p-STAT3, SLC2A1, HIF1α, and NOS2 expression levels. qPCR results show significant downregulation of the HIF-1 signaling pathway at cellular and tissue levels. Our study revealed that QX can significantly reduce the dorsal inflammatory response in the IMQ-induced psoriasis mouse model. Furthermore, we discovered that its main component, shikonin, exerts its therapeutic effect by diminishing the HIF-1 signaling pathway in HaCaT cells.

M2 Macrophage Polarization and Tissue Remodeling in Autologous Fat Grafting for Diabetic Skin Defects.

Autologous adipose tissue was recognized as a promising therapeutic option for soft tissue defects owing to its regenerative potential and ability to facilitate tissue reconstruction. However, the mechanisms by which autologous fat grafting (AFG) promotes healing remain unclear, hindering its potential applications. This study aimed to investigate the distribution and phenotypic transition of infiltrating macrophages in transplanted adipose tissue, as well as their correlation with diabetic skin defect remodeling. Streptozotocin-induced diabetic rats with full-thickness dorsal skin defects were included in this study. The transplanted adipose tissue at the skin defects was collected and analyzed using flow cytometry to determine macrophage proportion and phenotype. The healing of skin defects was evaluated, and treatment was continued until day 14 as the designated endpoint of healing, followed by histopathologic examinations. Immunostaining with CD31 and lymphatic vessel endothelial receptor-1 was performed on wound tissues to analyze angiogenesis and lymphangiogenesis, respectively. Western blot and quantitative polymerase chain reaction analyses were used to assess the expression of the representative genes involved in the healing process. The results showed early polarization of M2 macrophages in the transplanted adipose tissue, concomitant with the upregulation of growth factors and downregulation of inflammatory factors. In vivo experiments revealed that AFG significantly promoted macrophage infiltration and M2 transformation in diabetic skin defects compared to the control groups, thereby promoting tissue extracellular matrix remodeling and lymphatic and vascular regeneration. However, the beneficial effects of AFG were inhibited by macrophage depletion. This study further demonstrated the potential of AFG for treating diabetic skin defects.

Ameliorative effects of Wikstroemia trichotoma 95% EtOH extract on a mouse model of DNCB-induced atopic dermatitis

Ethnopharmacological relevanceThe genus Wikstroemia has been extensively utilized in traditional Chinese medicine (TCM) for the management of conditions such as coughs, edema, arthritis, and bronchitis. Studies have indicated that the crude extracts of Wikstroemia exhibit anti-inflammatory, anti-allergy, anti-aging, skin psoriasis, anti-cancer, and antiviral properties. In addition, these extracts are known to contain bioactive substances, including flavonoids, coumarins, and lignans. However, few studies have investigated the anti-inflammatory or anti-allergic activities of Wikstroemia trichotoma (Thunb.) Makino against atopic dermatitis (AD). Aim of the studyThe study aimed to explore the potential of a 95% ethanol extract of W. trichotoma (WTE) on the dysfunction of skin barrier and immune system, which are primary symptoms of AD, in 2,4-dinitrochlorobenzene (DNCB)-induced SKH-1 hairless mice and phorbol 12-myristate 13-acetate (PMA)/ionomycin or immunoglobulin E (IgE) + 2,4-dinitrophenylated bovine serum albumin (DNP-BSA) stimulated rat basophilic leukemia cell line (RBL-2H3). Furthermore, we sought to identify the chemical contents of WTE using high-performance liquid chromatography equipped with a photodiode array detector (HPLC-PDA). Materials and methodsAn in vitro study was conducted using RBL-2H3 cells stimulated with PMA/ionomycin or IgE + DNP-BSA to assess the inhibitory effects of WTE on mast cell degranulation and interleukin-4 (IL-4) mRNA expression levels. For the in vivo study, AD was induced in SKH-1 hairless mice by applying 1% DNCB to the dorsal skin daily for 7 days. Subsequently, 0.1% DNCB solution was applied on alternate days, and mice were orally administered WTE (at 30 or 100 mg/kg/day) dissolved in 0.5% carboxymethyl cellulose (CMC) daily for 2 weeks. Transepidermal water loss (TEWL), skin hydration, skin pH, and total serum IgE levels were measured. ResultsIn DNCB-stimulated SKH-1 hairless mice, WTE administration significantly improved AD symptoms and ameliorated dorsal skin inflammation. Oral administration of WTE led to a significant decrease in skin thickness, infiltration of mast cells, and level of total serum IgE, thus restoring skin barrier function in the DNCB-induced skin lesions. In addition, WTE inhibited β-hexosaminidase release and reduced IL-4 mRNA levels in RBL-2H3 cells. Chemical profile analysis of WTE confirmed the presence of three phenolic compounds, viz. chlorogenic acid, miconioside B, and matteucinol-7-O-β-apiofuranosyl (1 → 6)-β-glucopyranoside. ConclusionsWTE ameliorates AD symptoms by modulating in the skin barrier and immune system dysfunction. This suggests that W. trichotoma extract may offer therapeutic benefits for managing AD.

PL-Relief™plus AlleviatesAtopic Dermatitis and RegulatesInflammatory Responses via InhibitingNF-κB SignalingPathway.

Atopic dermatitis (AD) hasvarious detrimental effects on individuals with limited drug cure rates which necessitate the development of new treatment methods. PL-Relief™plus (PLR) is composed of SupraOlive, Crocus Sativus extracts and Citrus reticulata extracts. The effect of PLR on ADremains to be explored. 2,4-dinitrofluorobenzene-induced AD model mice were involved and the histopathology of the skin lesions was observed along with the levels of inflammatory chemokines levels were measured. To further validate the molecular mechanism of PLR, RNA-seq was performed inHaCaT cells. Western blotting and immunofluorescence were performed to investigate NF-κB signaling pathways response in AD. Due to PLR treatment, the thickening of the epidermis and dermis was inhibited and thenumber of eosinophils, mast cells, and CD4+T cells in the skin lesion was decreased. In addition, the levels of inflammatory cytokines were decreased in dorsal skin tissues and LPS-stimulated HaCat cells. Furthermore, KEGG pathway analysis suggested that most identified downstream biological functions were associated with inflammatory response. PLR inhibited NF-κB signaling in AD mice and HaCaT cells. These results indicate that PLR is a potent therapeutic agent for attenuating symptoms of AD.

Photodynamic therapy mediated by methylene blue-loaded PEG accelerates skin mouse wound healing: an immune response.

Conventional approaches for enhancing wound healing may not always yield satisfactory results. Instead, we test the effectiveness of a newly developed photodynamic therapy (PDT) that uses methylene blue (MB) loaded with polyethylene glycol (PEG) (MB-PEG) hydrogel to accelerate wound healing process in mice. A dorsal skin incision with 6mm punch which topically subjected to MB-PEG hydrogel and a low-level laser light of red light to assess the regeneration process of wounded skin. A total of 63 adult male CD1 mice divided into normal group (no treatment) and other wound groups received different treatments of laser (650 ± 5nm and power intensity of 180 mW/cm2), MB-PEG, or PDT (MB-PEG followed by laser). The wound healing parameters were investigated by histological examination of the skin and measuring of proinflammatory cytokines at the early stage (48h) and a late one on day 21. at 48h, the score of tissue granulation, inflammation, and angiogenesis process were markedly improved in wounded groups that received MB + PEG combined with laser compared to the group treated with laser alone. On day 21, a significant improvement of the inflammation was detected in the group treated with MB + PEG plus laser compared to the other groups. At 48h, the upregulated serum levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in the wound group were significantly (P < 0.001) reduced in the group treated with MB + PEG combined with laser. MB-PEG based hydrogel improves and accelerates wound closure in the context of laser compared to either single treatment.

Transcriptome analysis of sexual dimorphism in dorsal down coloration in goslings

BackgroundIn day-old Hungarian white goose goslings, there is a noticeable difference in dorsal down coloration between males and females, with females having darker dorsal plumage and males having lighter plumage. The ability to autosex day-old goslings based on their dorsal down coloration is important for managing them efficiently and planning their nutrition in the poultry industry. The aim of this study was to determine the biological and genetic factors underlying this difference in dorsal down colorationthrough histological analysis, biochemical assays, transcriptomic profiling, and q‒PCR analysis.ResultsTissue analysis and biochemical assays revealed that compared with males, 17-day-old embryos and day-old goslings of female geese exhibited a greater density of melanin-containing feather follicles and a greater melanin concentration in these follicles during development. Both female and male goslings had lower melanin concentrations in their dorsal skin compared to 17-day-old embryos. Transcriptome analysis identified a set of differentially expressed genes (DEGs) (MC1R, TYR, TYRP1, DCT and MITF) associated with melanogenesis pathways that were downregulated or silenced specifically in the dorsal skin of day-old goslings compared to 17-day-old embryos, affecting melanin synthesis in feather follicles. Additionally, two key genes (MC1R and MITF) associated with feather coloration showed differences between males and females, with females having higher expression levels correlated with increased melanin synthesis and darker plumage.ConclusionThe expression of multiple melanogenesis genes determines melanin synthesis in goose feather follicles. The dorsal down coloration of day-old Hungarian white goose goslings shows sexual dimorphism, likely due to differences in the expression of the MC1R and MITF genes between males and females. These results could help us better understand why male and female goslings exhibit different plumage patterns.

Reprofiling synthetic glucocorticoid-induced leucine zipper fusion peptide as a novel and effective hair growth promoter.

Hair is a biofilament with unique multi-dimensional values. In human, in addition to physiologic impacts, hair loss and hair related disorders can affect characteristic features, emotions, and social behaviors. Despite significant advancement, there is a dire need to explore alternative novel therapies with higher efficacy, less side effects and lower cost to promote hair growth to treat hair deficiency. Glucocorticoid-induced leucine zipper (GILZ) is a protein rapidly induced by glucocorticoids. Studies from our group and many others have suggested that a synthetic form of GILZ, TAT-GILZ, a fusion peptide of trans-activator of transcription and GILZ, can function as a potent regulator of inflammatory responses, re-establishing and maintaining the homeostasis. In this study, we investigate whether TAT-GILZ could promote and contribute to hair growth. For our pre-clinical model, we used 9-12 week-old male BALB/c and nude (athymic, nu/J) mice. We applied TAT-GILZ and/or TAT (vehicle) intradermally to depilated/hairless mice. Direct observation, histological examination, and Immunofluorescence imaging were used to assess the effects and compare different treatments. In addition, we tested two current treatment for hair loss/growth, finasteride and minoxidil, for optimal evaluation of TAT-GILZ in a comparative fashion. Our results showed, for the first time, that synthetic TAT-GILZ peptide accelerated hair growth on depilated dorsal skin of BALB/c and induced hair on the skin of athymic mice where hair growth was not expected. In addition, TAT-GILZ was able to enhance hair follicle stem cells and re-established the homeostasis by increasing counter inflammatory signals including higher regulatory T cells and glucocorticoid receptors. In conclusion, our novel findings suggest that reprofiling synthetic TAT-GILZ peptide could promote hair growth by increasing hair follicle stem cells and re-establishing homeostasis.

The effect of anatomic location on porcine models of burn injury and wound healing.

Porcine models are frequently used for burn healing studies; however, factors including anatomic location and lack of standardised wound methods can impact the interpretation of wound data. The objectives of this study are to examine the influence of anatomical locations on the uniformity of burn creation and healing in porcine burn models. To optimise burn parameters on dorsal and ventral surfaces, ex vivo and in situ euthanized animals were first used to examine the location-dependence of the burn depth and contact time relationship. The location-dependent healing in vivo was then examined using burn and excisional wounds at dorsal, ventral, caudal and cranial locations. Lactate dehydrogenase (LDH) and H&E were used to assess burn depth and wound re-epithelialization. We found that burn depth on the ventral skin was significantly deeper than that of the dorsal skin at identical thermal conditions. Compared with burns created ex vivo, burns created in situ immediately post-mortem were significantly deeper in the ventral location. In live animals, 2 out of 12 burn wounds were fully re-epithelialized after 14 days in contrast to complete re-epithelialization of all excisional wounds. Among the burn wounds, those at the cranial-dorsal site exhibited faster healing than at the caudal-dorsal site. This study showed that anatomical location is an important consideration for the consistency of burn depth creation and healing. These data support symmetric localization of treatment and control for comparative assessment of burn healing in porcine models to prevent misinterpretation of results and increase the translatability of findings to humans.

Naringenin, a flavanone constituent from Sea buckthorn pulp extract, prevents ultraviolet (UV)-B radiation-induced skin damage via alleviation of impaired mitochondrial dynamics mediated inflammation in human dermal fibroblasts and Balb/c mice models

Ultraviolet-B (UV-B) irradiation has been reported to cause oxidative stress and inflammation-mediated skin photo-damage. Furthermore, mitochondrial dynamics have been implicated to play a critical role in these processes. For the first time, we describe in this study how UVB-induced aberrant mitochondrial dynamics and inflammation interact in primary human dermal fibroblasts (HDFs). Our findings demonstrated that UV-B irradiation induced -impairment in mitochondrial dynamics by increasing mitochondrial fragmentation in HDFs. Imbalanced mitochondrial dynamics lead to the activation of NFкB and pro-inflammatory cytokines. The current study further aimed to investigate the protective effect of Naringenin (a naturally occurring flavonoid isolated from Sea buckthorn fruit pulp) against UV-B-induced mitochondrial fragmentation and inflammation in HDFs and Balb/c mice. Although Naringenin has been shown to have anti-inflammatory and antioxidant potential, its effects and mechanisms of action on UVB-induced inflammation remained unclear. We observed that Naringenin restored the UV-B-induced imbalance in mitochondrial fission and fusion in HDFs. It also inhibited the phosphorylation of NFкB and reduced the generation of pro-inflammatory cytokines. Naringenin also alleviated UV-B-induced oxidative stress by scavenging the reactive oxygen species and up-regulating the cellular antioxidant enzymes (Catalase and Nrf2). Topical application of Naringenin to the dorsal skin of Balb/c mice exposed to UV-B radiation prevented mitochondrial fragmentation and progression of inflammatory responses. Naringenin treatment prevented neutrophil infiltration and epidermal thickening in mice's skin. These findings provide an understanding for further research into impaired mitochondrial dynamics as a therapeutic target for UV-B-induced inflammation. Our findings imply that Naringenin could be developed as a therapeutic remedy against UVB-induced inflammation.

Low-concentration imiquimod treatment promotes enhanced skin barrier functions through epidermal melanization reaction regulation.

The primary function of the skin is to form a mechanical, permeability, antimicrobial, and ultraviolet radiation barrier, which is essential for maintaining physiological homeostasis. Our previous studies demonstrated that cutaneous pigmentation could promote skin barrier function in addition to providing anti-ultraviolet irradiation defense. The present study aimed to develop a new regimen that enhances skin barrier function by regulating skin pigmentation using low-concentration imiquimod. Results showed that topical application of low-concentration imiquimod effectively induced skin hyperpigmentation in the dorsal skin and external ear of mice without inducing inflammatory cell infiltration. An in vitro study also revealed that low-concentration imiquimod did not induce any cytotoxic effects on melanoma cells but triggered excessive melanin synthesis. In coculture systems, low-concentration imiquimod was noted to increase tyrosinase activity in a broader cellular context, revealing the potential role of neighboring cells in melanin production. The next-generation sequencing result indicated that PKCη and Dnm3 might regulate melanin synthesis and release during imiquimod treatment. Overall, our study presents new insights into the regulation of melanin production by low-concentration imiquimod, both in a mice model and cultured cells. Furthermore, our study highlights the potential benefits of imiquimod in promoting melanin synthesis without causing skin disruptions or inducing inflammation, validating its potential to serve as a method for enhancing skin barrier functions by regulating the epidermal melanization reaction.

Comparative transcriptomic analyses reveal key genes underlying melanin distribution during embryonic development in geese (Anser anser)

ABSTRACT 1. Melanin distribution typically exhibits a gradient dilution along the dorsal-ventral axis of the body, including in domestic geese. However, the specific genes and molecular mechanisms responsible for this melanin distribution pattern remain incompletely understood. 2. The transcriptomic comparisons were conducted at three embryonic stages, specifically on embryonic d 15 (E15), 22 (E22), and 29 (E29), between the pigmented dorsal skin and the depigmented distal foot. 3. Differentially expressed genes (DEGs) associated with melanin synthesis were identified, particularly TYR, TYRP1, and EDNRB2, which exhibited significantly higher expression levels in the dorsal skin at E15 and E22. However, expression levels significantly decreased in later stages (E29). 4. The ASIP gene showed remarkably high-expression levels in the distal feet compared to the dorsal skin post-E22 stage (log2FC: 5.31/6.88 at E22/E29). Gene Ontology (GO) enrichment analysis detected eight terms associated with melanin synthesis and melanosome formation (p < 0.05), including melanosome membrane (GO: 0033162) and melanin biosynthetic process (GO: 0042438). Additionally, KEGG pathway analysis showed significant enrichment of the melanogenesis pathway (hsa004916) at d 22 (E22).

Co-Delivery of Recombinant Super-Affinity VEGF and PDGF-BB Accelerates Diabetic Wound Healing by Improving Angiogenesis, Arteriogenesis and Blood Flow

Abstract Background Diabetic ulcers are characterized by local ischemia, usually without macroangiopathy. We have previously found that the combination of VEGF and PDGF-BB in a fibrin matrix is effective in stimulating arterial growth to diabetic wounds. Aims We developed modified forms of VEGF and PDGF-BB to bear super-affinity for the extracellular matrix (SA-VP), in order to decorate the wound tissue without the need for a biomaterial. We investigated the dose-dependent effects on local blood flow and wound healing, by applying the treatment either to the healthy tissue around the wound or to the damaged wound bed. Methods Full thickness wounds were created on the dorsal skin of diabetic (db/db) mice. SA-VP or saline were applied to the wound bed or divided into 4 injections around the wound edge. Wound closure and blood flow were measured on days 4 and 8 after treatment and tissues were harvested for histology on day 8. Data were analysed by Anova with Tukey’s post-hoc test for multiple comparisons. Results Wound healing was improved dose-dependently by SA-VP by both delivery routes. Histologically, angiogenic areas and total amount of angiogenesis were significantly increased by the highest SA-VP dose, again independent of delivery route (p = 0.034). However, the total amount of recruited arterioles was significantly increased only in the healthy tissue around the wound and only by intradermal injections of SA-VP (p = 0.008). In agreement with the arteriogenic effect, the blood flow at day 4 was significantly increased only by injections of the highest SA-VP dose around the wound (p = 0.018). Conclusion SA-VP treatment significantly accelerates wound healing in a diabetic murine model with a clear dose-dependent effect. Targeting the undamaged tissue around the wound by injections induces more effective arteriogenesis. However, direct treatment of the wound bed is equally effective for healing. These results support further development for a potential clinical use.

DNA Microarray and Bioinformatic Analysis Reveals the Potential of Whale Oil in Enhancing Hair Growth in a C57BL/6 Mice Dorsal Skin Model.

Much research has been conducted to determine how hair regeneration is regulated, as this could provide therapeutic, cosmetic, and even psychological interventions for hair loss. The current study focused on the hair growth effect and effective utilization of fatty oil obtained from Bryde's whales through a high-throughput DNA microarray approach in conjunction with immunohistochemical observations. The research also examined the mechanisms and factors involved in hair growth. In an experiment using female C57BL/6J mice, the vehicle control group (VC: propylene glycol: ethanol: water), the positive control group (MXD: 3% minoxidil), and the experimental group (WO: 20% whale oil) were topically applied to the dorsal skin of the mouse. The results showed that 3% MXD and 20% WO were more effective than VC in promoting hair growth, especially 20% WO. Furthermore, in hematoxylin and eosin-stained dorsal skin tissue, an increase in the number of hair follicles and subcutaneous tissue thickness was observed with 20% WO. Whole-genome transcriptome analysis also confirmed increases for 20% WO in filaggrin (Flg), a gene related to skin barrier function; fibroblast growth factor 21 (Fgf21), which is involved in hair follicle development; and cysteine-rich secretory protein 1 (Crisp1), a candidate gene for alopecia areata. Furthermore, the results of KEGG pathway analysis indicated that 20% WO may have lower stress and inflammatory responses than 3% MXD. Therefore, WO is expected to be a safe hair growth agent.

Biotransformation of Cacumen platycladi Extract by Lactiplantibacillus plantarum CCFM1348 Promotes Hair Growth in Mice.

Cacumen platycladi (CP) is a frequently used traditional Chinese medicine to treat hair loss. In this study, CP fermented by Lactiplantibacillus plantarum CCFM1348 increased the proliferation of human dermal papilla cells. In an in vivo assay, compared to nonfermented CP, postbiotics (fermented CP) and synbiotics (live bacteria with nonfermented CP) promoted hair growth in mice. The Wnt/β-catenin signaling pathway plays crucial roles in the development of hair follicles, including growth cycle restart and maintenance. Both postbiotics and synbiotics upregulated β-catenin, a major factor of the Wnt/β-catenin signaling pathway. Postbiotics and synbiotics also increased the vascular endothelial growth factor expression and decreased the BAX/Bcl2 ratio in the dorsal skin of mice. These results suggest that fermented CP by L. plantarum CCFM1348 may promote hair growth through regulating the Wnt/β-catenin signaling pathway, promoting the expression of growth factors and reducing apoptosis.

Single nucleotide polymorphisms in the KRT82 promoter region modulate irregular thickening and patchiness in the dorsal skin of New Zealand rabbits

BackgroundWhile rabbits are used as models in skin irritation tests, the presence of irregular patches and thickening on the dorsal skin can affect precise evaluation. In this study, genes associated with patchiness or non-patchiness on the dorsal skin of New Zealand rabbits were investigated to identify potential regulators of the patchiness phenotype.ResultsThe results showed that parameters associated with hair follicles (HFs), such as HF density, skin thickness, and HF depth, were augmented in rabbits with the patchiness phenotype relative to the non-patchiness phenotype. A total of 592 differentially expressed genes (DEGs) were identified between the two groups using RNA-sequencing. These included KRT72, KRT82, KRT85, FUT8, SOX9, and WNT5B. The functions of the DEGs were investigated by GO and KEGG enrichment analyses. A candidate gene, KRT82, was selected for further molecular function verification. There was a significant positive correlation between KRT82 expression and HF-related parameters, and KRT82 overexpression and knockdown experiments with rabbit dermal papilla cells (DPCs) showed that it regulated genes related to skin and HF growth and development. Investigation of single nucleotide polymorphisms (SNPs) in the exons and promoter region of KRT82 identified four SNPs in the promoter region but none in the exons. The G.-631G > T, T.-696T > C, G.-770G > T and A.-873 A > C alleles conformed to the Hardy − Weinberg equilibrium, and three identified haplotypes showed linkage disequilibrium. Luciferase reporter assays showed that the core promoter region of KRT82 was located in the − 600 to − 1200 segment, in which the four SNPs were located.ConclusionsThe morphological characteristics of the patchiness phenotype were analyzed in New Zealand rabbits and DEGs associated with this phenotype were identified by RNA-sequencing. The biological functions of the gene KRT82 associated with this phenotype were analyzed, and four SNPs were identified in the promoter region of the gene. These findings suggest that KRT82 may be a potential biomarker for the breeding of experimental New Zealand rabbits.

The discovery of a novel pyrrolo[2,3-b]pyridine as a selective CDK8 inhibitor offers a new approach against psoriasis

Currently, the drugs used in clinical to treat psoriasis mainly broadly suppress cellular immunity. However, these drugs can only provide temporary and partial symptom relief, they do not cure the condition and may lead to recurrence or even serious toxic side effects. In this study, we describe the discovery of a novel potent CDK8 inhibitor as a treatment for psoriasis. Through structure-based design, compound 46 was identified as the most promising candidate, exhibiting a strong inhibitory effect on CDK8 (IC50 value of 57 nM) along with favourable inhibition against NF-κB. Additionally, it demonstrated a positive effect in an in vitro psoriasis model induced by TNF-α. Furthermore, this compound enhanced the thermal stability of CDK8 and exerted evident effects on the biological function of CDK8, and it had favourable selectivity across the CDK family and tyrosine kinase. This compound showed no obvious inhibitory effect on CYP450 enzyme. Further studies confirmed that compound 46 exhibited therapeutic effect on IMQ-induced psoriasis, alleviated the inflammatory response in mice, and enhanced the expression of Foxp3 and IL-10 in the dorsal skin in vivo. This discovery provides a new strategy for developing selective CDK8 inhibitors with anti-inflammatory activity for the treatment of psoriasis.

Experimental investigation on the transient vascular thermal response to laser irradiation by a high-speed infrared thermal camera

Based on the photothermal effect, laser can be used to treat vascular diseases (VD) in clinic of dermatology and ophthalmology. Transient vascular thermal response to laser irradiation during millisecond laser pulse is the key phenomenon in treatment process, which has not been carefully investigated before. In this study, target blood vessels in dorsal skin chamber (DSC) animal model were irradiated by a pulsed 532 nm diode laser and a 1064 nm Nd:YAG laser. The directed thermal responses (temperature variation) were recorded by a high-speed infrared thermal camera with a repetition rate of 1000 Hz. The temperature variation during and after single pulse irradiation and multipulse irradiation were investigated. The variation of blood absorption coefficient was explored based on the temperature increment in each laser pulse. The thermal properties of dorsal skin, especially the thermal diffusivity, were evaluated based on the temperature decay after each laser pulse. The interfacial heat transfer between the blood and the surroundings was also calculated based on the thermal images and compared to the correlation proposed before. The results show that the blood absorption to laser will increase by a maximum of 1.9 immediately after blood temperature exceeds threshold value, e.g., 68oC in both single pulse (pulse duration >100 ms) and multi-pulse laser irradiation. The tissue optical properties (thermal diffusivity) keep almost constant after millisecond laser heating. Also, a general correlation for interfacial heating transfer between blood and surroundings was developed, in which the influences of vessel shape and laser wavelength are incorporated. The interfacial heat transfer between blood and surrounding can be accurately quantified.

Are periodontitis and psoriasis associated? A pre-clinical murine model.

To investigate the bidirectional influence between periodontitis and psoriasis, using the respective experimental models of ligature- and imiquimod-induced diseases on murine models. Thirty-two C57/BL6J mice were randomly allocated to four experimental groups: control (P- Pso-), ligature-induced periodontitis (P+ Pso-), imiquimod-induced psoriasis (P- Pso+) and periodontitis and psoriasis (P+ Pso+). Samples (maxilla, dorsal skin and blood) were harvested immediately after death. Measures of periodontitis (distance between the cemento-enamel junction and alveolar bone crest [CEJ-ABC] and the number of osteoclasts) and psoriasis (epidermal thickness and infiltrate cell [/0.03mm2]) severity as well as systemic inflammation (IL-6, IL-17A, TNF-α) were collected. The P+ Pso+ group exhibited the most severe experimental periodontitis and psoriasis, with the highest values of CEJ-ABC, number of osteoclasts, epidermal thickness and infiltrate cells in the dorsal skin, as well as the highest blood cytokine concentration. The P+ Pso- group presented with higher cell infiltrate (/0.03mm2) compared to the control group (p <.05), while the P- Pso+ group showed substantially higher alveolar bone loss (CEJ-ABC) than the control group (p <.05). Experimental periodontitis may initiate and maintain psoriasiform skin inflammation and, vice versa, experimental psoriasis may contribute to the onset of periodontitis. In a combined model of the diseases, we propose a bidirectional association between periodontitis and psoriasis via systemic inflammation.

Translation of paclitaxel-induced peripheral neurotoxicity from mice to patients: the importance of model selection.

Paclitaxel-induced peripheral neurotoxicity (PIPN) is a potentially dose-limiting side effect in anticancer chemotherapy. Several animal models of PIPN exist, but their results are sometimes difficult to be translated into the clinical setting. We compared 2 widely used PIPN models characterized by marked differences in their methodologies. Female C57BL/6JOlaHsd mice were used, and they received only paclitaxel vehicle (n = 38) or paclitaxel via intravenous injection (n = 19, 70 mg/kg) once a week for 4 weeks (Study 1) or intraperitoneally (n = 19, 10 mg/kg) every 2 days for 7 times (Study 2). At the end of treatment and in the follow-up, mice underwent behavioral and neurophysiological assessments of PIPN. At the same time points, some mice were killed and dorsal root ganglia, skin, and sciatic and caudal nerve samples underwent pathological examination. Serum neurofilament light levels were also measured. The differences in the neurotoxicity parameters were analyzed using a nonparametric Mann-Whitney test, with significance level set at P < 0.05. Study 1 showed significant and consistent behavioral, neurophysiological, pathological, and serological changes induced by paclitaxel administration at the end of treatment, and most of these changes were still evident in the follow-up period. By contrast, study 2 evidenced only a transient small fiber neuropathy, associated with neuropathic pain. Our comparative study clearly distinguished a PIPN model recapitulating all the clinical features of the human condition and a model showing only small fiber neuropathy with neuropathic pain induced by paclitaxel.