Epidermal Keratin Research Articles

TERATOGENIC EFFECTS OF TOPICALLY APPLIED PARAPHENYLENEDIAMINE ON THE RAT FOETUS

Background: Paraphenylenediamine (PPD) is an organic compound used in hair dye. It causes local and systemic side-effects. Not much is known regarding its foetotoxic effects. This study aimed at determining the teratogenic effects of topically applied PPD. Methods: This experimental study was carried out at IBMS, Khyber Medical University, and Peshawar Medical College, Peshawar over a period of 6 months. Twenty healthy Sprague Dawely female pregnant rats were divided into 5 groups, i.e., positive control (Group A), control (Group B), and 3 experimental groups (C, D, and E). For group A, 0.1 ml of distilled water was applied topically on back of each rat. For positive control group B, 0.5 ml of dye containing 3% PPD was applied, while for group C, D and E, 1, 2 and 3 mg/Kg dose of PPD respectively was applied for 30 minutes daily. Skin was washed followed by rats mating. After successful fertilization, same doses were repeated for 20 days. Animals were sacrificed and foetuses were examined for skeletal abnormalities and hepatic changes. Skin biopsy of adult rats was examined for any changes. Result: Topically applied PPD resulted in significant teratogenic effects on foetal liver in a dose dependent manner. However, no significant teratogenic effect was observed on foetal skeleton (p=0.075). Topical PPD showed increased epidermal thickening and keratinization on adult rats skin. Conclusion: PPD has significant dermal effects on adult rats and teratogenic effects on liver of rat foetuses but no significant effects were observed on foetal skeleton. Pak J Physiol 2022;18(2):15?21

Darier-White disease and Psychiatric disorders: A Case Report

IntroductionDarier-White disease (DD) is a rare genodermatosis of dominant autosomic inheritance characterized by the keratinization of epidermis, nails and mucous membrane. It leads to the formation of papules and brown hyperkeratotic plaques, mainly in seborrheic areas. The disease is associated with a mutation on the ATP2A2 gene, mapped in the 12q23-24 chromosome. There is known a relationship between DD and neuropsychiatric diseases, such as bipolar disorder, depression and schizophrenia.ObjectivesTo discuss the relationship between DD and neuropshychiatric disorders.MethodsWe report the case of a patient with diagnosed schizophrenia, alcohol and cannabis dependence who presented skin lesions.ResultsThe physical exploration of our patient revealed cutaneous lesions and we pointed the diagnostic towards DD. Afterwards, a cross-consultation was done with the dermatology experts. During the physical exploration, the patient shows confluent hyperkeratotic papules, dominant on the sides and center of back and hands, together with nail injuries (see images). The diagnostic was confirmed through anatomic pathology. The patient was treated with 10 mg/day of Acitretin together with emollients twice a day, which improved the patient clinical status and signs. The patient remained stable at a psychiatric standpoint. After 3 years of treatment, the patient keeps the same medication but with a reduced dose of 5 mg/day, with a 70% decrease of the initial hyperkeratotic lesions.ConclusionsPrevious studies concludes that mutations in the ATP2A2 gene, in addition to causing DD, confer susceptibility to neuropsychiatric features.These case report highlight the need for clinicians to asses and recognize neuropsychiatric symptoms in DD.DisclosureNo significant relationships.

Activation of the C3a anaphylatoxin receptor inhibits keratinocyte proliferation by regulating keratin 6, keratin 16, and keratin 17 in psoriasis.

Emerging evidence suggests that signaling through the C3a anaphylatoxin receptor (C3aR) protects against various inflammation-related diseases. However, the role of C3aR in psoriasis remains unknown. The purpose of this study was to investigate the possible protective role of C3aR in psoriasis and to explore the underlying molecular mechanisms. We initially found that the psoriatic epidermis exhibited significantly decreased C3aR expression. C3aR showed protective roles in mouse models of imiquimod (IMQ)- and interleukin-23-induced psoriasis. Furthermore, increased epidermal thickness and keratin 6 (K6), K16, and K17 expression occurred in the ears and backs of C3aR-/- mice. Pharmacological treatment with a C3aR agonist ameliorated IMQ-induced psoriasiform lesions in mice and decreased the expression of K6, K16, and K17. Additionally, the signal transducer and activator of transcription 3 (STAT3) pathway participated in the protective function of C3aR. More importantly, the expression levels of K6, K16, and K17 in keratinocytes were all restored in HaCaT cells transfected with a C3aR-overexpression plasmid after treating them with colivelin (a STAT3 activator). Our findings demonstrate that C3aR protects against the development of psoriasis and suggest that C3aR confers protection by negatively regulating K6, K16, and K17 expression in a STAT3-dependent manner, thus inhibiting keratinocyte proliferation and helping reverse the pathogenesis of psoriasis.

PP2Acα regulates epidermal cell proliferation via the EGFR/AKT/mTOR pathway in psoriasis-like skin lesions caused by PPP2CA deficiency.

Psoriasis, a common skin disease, endangers human physiological and mental health; however, its pathogenesis remains unclear. Keratinocyte proliferation is a typical pathological characteristic of psoriasis. Serine/threonine protein phosphatase 2A (PP2A) is one of the most important phosphatases for maintaining normal phosphorylation levels in humans. PP2Acα is the alpha subtype of the PP2A C subunit (encoded by PPP2CA), which maintains the catalytic functions of PP2A. Epidermal growth factor receptor (EGFR) is activated by phosphorylation (p-EGFR) to regulate the downstream signalling pathway to promote epidermal cell proliferation. Previous studies have found that PPP2CA induced epidermal hyperplasia, keratinization and other pathological phenomena similar to those in mouse models of psoriasis. The present study showed that PP2Acα negatively regulated EGFR phosphorylation and epidermal cell proliferation, and EGFR inhibitors could alleviate PP2Acα by inhibiting epidermal cell proliferation. This study further examined the effect of mechanisms on epidermal cell proliferation and the downstream signalling pathway of EGFR using molecular technological methods to explore new ideas for treating psoriasis.

ΔNp63-Senataxin circuit controls keratinocyte differentiation by promoting the transcriptional termination of epidermal genes

SignificanceΔNp63 is a master regulator of skin homeostasis since it finely controls keratinocyte differentiation and proliferation. Here, we provide cellular and molecular evidence demonstrating the functional role of a ΔNp63 interactor, the R-loop-resolving enzyme Senataxin (SETX), in fine-tuning keratinocyte differentiation. We found that SETX physically binds the p63 DNA-binding motif present in two early epidermal differentiation genes, Keratin 1 (KRT1) and ZNF750, facilitating R-loop removal over their 3' ends and thus allowing efficient transcriptional termination and gene expression. These molecular events translate into the inability of SETX-depleted keratinocytes to undergo the correct epidermal differentiation program. Remarkably, SETX is dysregulated in cutaneous squamous cell carcinoma, suggesting its potential involvement in the pathogenesis of skin disorders.

Microscopical observations on the regenerating tail of tsinling dwarf skink (Scincella tsinlingensis)

Although the key steps of tail regeneration in lizards are well understood, further investigations involving skinks can provide the field of regeneration research with additional information. In order to characterize the cytoarchitecture of tail regeneration in Scincella tsinlingensis, an endemic species in China, its histological events and growth trends are investigated. The rate of tail regeneration varies with the season: it proceeds faster in summer and autumn than it does in winter and spring. Tail regeneration of S. tsinlingensis is summarized as wound healing, blastema formation, cell differentiation and tail growth, which can be subdivided into seven stages. Wound healing following tail loss, begins with an obvious outgrowth undergoing re-epithelialization. Numerous proliferating mesenchymal-like cells aggregate near the distal end of the severed spinal cord to form the blastema. The expanding blastema is invaded by blood vessels, nerves and ependyma. A cartilaginous skeleton is formed around the ependymal tube and the muscle starts to differentiate. The keratinization of epidermis coincides with scale formation. Pigmentation eventually occurs in the regenerated tail. Tail regeneration in S. tsinlingensis is an epimorphic kind of regeneration that is also known as blastema-mediated. Structure and composition of the regenerated tail, including its cytoarchitecture, represent a conserved pattern of regeneration also known from other lizards.

Penile porokeratosis mimicking annular lichen planus

Sir, Porokeratosis is a group of cutaneous diseases presented by epidermal keratinization [1]. Herein, we report the case of a patient with porokeratosis who responded well to carbon dioxide (CO2) laser therapy. A 22-year-old Vietnamese male visited our department with an asymptomatic plaque on the penis present for three months. He denied a family history of similar lesions. A cutaneous examination of the penis revealed an annular, well-circumscribed plaque with slightly raised borders with scales (Fig. 1a). Other mucocutaneous lesions were absent. Fungal microscopy, a rapid plasma reagin (RPR) test, and a Treponema pallidum hemagglutination (TPHA) test were negative. Histological findings revealed a hyperkeratotic lesion with a discrete parakeratotic column. There was the presence of a cornoid lamella, which was a parakeratotic column overlying a small vertical zone of dyskeratotic and vacuolated cells within the epidermis (Fig. 2a). There was also a focal loss of the granular layer. A mild lymphocytic infiltrate could be seen around an increased number of capillaries in the underlying dermis (Fig. 2b). CO2 laser removal was performed. There was no recurrence after a twelve-month follow-up (Fig. 1b). However, a hypopigmented scar was seen. Porokeratosis is an uncommon disorder of keratinization with clinical variants, such as classical porokeratosis of Mibelli, disseminated superficial actinic porokeratosis, linear porokeratosis, and porokeratosis palmaris et plantaris disseminata [2]. Porokeratosis involving the genital areas and other adjacent sites is rare [2]. Genital porokeratosis was first described by Helfman in 1985 [3]. More than 69 cases have been reported in the literature [1]. The pathophysiology of genital porokeratosis remains unknown. It has been supposed that porokeratosis is linked to repeated minor frictional trauma. A benign lesion may transform into squamous cell carcinoma or basal cell carcinoma [4]. However, no malignant transformation of genital porokeratosis has been noted in the literature. Genital porokeratosis manifests itself clinically as classic or plaque-type porokeratosis of Mibelli [2]. Histological findings revealed a cornoid lamella with the absence of a granular layer and dyskeratotic cells in the upper spinous zone [2]. Our case may mimic some annular lesions, such as secondary syphilis, fungal infection, and annular lichen planus. Because a fungal examination and syphilis serology were negative, we could exclude fungal infection and annular secondary syphilis. The distinctive histology of porokeratosis such as a cornoid lamella with a decreased granular layer may help to differentiate between porokeratosis and annular lichen planus [4]. Numerous therapeutic methods of treatment exist, including surgical excision, CO2 laser, cryotherapy, topical retinoids, 5% 5-fluorouracil, vitamin D3 analogs, imiquimod cream, and 3% diclofenac gel [2,5].

Transcriptome Analysis Reveals Intrinsic Proinflammatory Signaling in Healthy African American Skin

Differences in the morphology and physiology of darkly pigmented skin compared with those of lightly pigmented skin are well-recognized. There are also disparities in the prevalence and clinical features for many inflammatory skin diseases, including atopic dermatitis and psoriasis; however, the underlying mechanisms are largely unknown. We compared the baseline gene expression in full-thickness skin biopsies from healthy individuals self-reporting as African American (AA) or as White non-Hispanic (WNH). Extensively validated RNA-sequencing analysis identified 570 differentially expressed genes in AA skin, including Igs and their receptors such as FCER1G; proinflammatory genes such as TNFα and IL32; and epidermal differentiation cluster and keratin genes. Differentially expressed genes were functionally enriched for inflammatory responses, keratinization, and cornified envelope formation. RNA-sequencing analysis of three-dimensional human skin equivalents made from AA and WNH primary keratinocytes revealed 360 differentially expressed genes (some shared with skin) that were enriched by similar functions. AA human skin equivalents appeared more responsive to TNF-α proinflammatory effects. Finally, AA-specific differentially expressed genes in the skin and human skin equivalents significantly overlapped with molecular signatures of skin in patients with atopic dermatitis and psoriasis. Overall, these findings suggest the existence of intrinsic proinflammatory circuits in AA keratinocytes/skin that may account for disease disparities and will help to build a foundation for the development of targeted skin disease prevention.

Newborn infant skin gene expression: Remarkable differences versus adults.

At birth, human infants are poised to survive in harsh, hostile conditions. An understanding of the state of newborn skin development and maturation is key to the maintenance of health, optimum response to injury, healing and disease. The observational study collected full-thickness newborn skin samples from 27 infants at surgery and compared them to skin samples from 43 adult sites protected from ultraviolet radiation exposure, as the standard for stable, mature skin. Transcriptomics profiling and gene set enrichment analysis were performed. Statistical analysis established over 25,000 differentially regulated probe sets, representing 10,647 distinct genes, in infant skin compared to adult skin. Gene set enrichment analysis showed a significant increase in 143 biological processes (adjusted p < 0.01) in infant skin, versus adult skin samples, including extracellular matrix (ECM) organization, cell adhesion, collagen fibril organization and fatty acid metabolic process. ECM organization and ECM structure organization were the biological processes in infant skin with the lowest adjusted P-value. Genes involving epidermal development, immune function, cell differentiation, and hair cycle were overexpressed in adults, representing 101 significantly enriched biological processes (adjusted p < 0.01). The processes with the highest significant difference were skin and epidermal development, e.g., keratinocyte differentiation, keratinization and cornification intermediate filament cytoskeleton organization and hair cycle. Enriched Gene Ontology (GO) biological processes also involved immune function, including antigen processing and presentation. When compared to ultraviolet radiation-protected adult skin, our results provide essential insight into infant skin and its ability to support the newborn’s preparedness to survive and flourish, despite the infant’s new environment laden with microbes, high oxygen tension and potential irritants. This fundamental knowledge is expected to guide strategies to protect and preserve the features of unperturbed, young skin.

132 Increased BMP Signalling Correlates with Increased Eczema Severity

Filaggrin (FLG) is a key cornified envelope and epidermal barrier protein. FLG mutations are the most strongly implicated genetic risk factor for atopic eczema (AE). FLG is part of a gene complex, called the epidermal differentiation complex (EDC), the genes of which contribute to various aspects of epidermal barrier function. A number of EDC and Keratin genes were downregulated and components of the bone morphogenetic protein (BMP) signalling pathway upregulated in RNA-seq from FLG siRNA knockdown keratinocytes. This led us to speculate that BMP signalling is an important pathway in the pathogenesis of AE. Western blotting and qPCR was performed on lysates from FLG siRNA knockdown keratinocytes. Western blotting was performed from lysates extracted form tape strips taken from AE patients who were clinically phenotyped and genotyped for FLG mutation status. FLG knockdown caused significant reduction in FLG, Keratin 1, Keratin 10, Loricrin, Repetin and SPRR3 protein and RNA expression and an increase in phospho-SMAD (p-SMAD) 1/5 signaling, a marker of active BMP signaling. Western blots of tape strip samples taken from AE patients showed no correlation of EDC, Keratins or SMAD proteins with FLG expression but a statistically significant increase in p-SMAD 1/5 signalling in FLG compound heterozygote patients and a statistically significant correlation between EASI score and p-SMAD 1/5 expression in non-lesional skin. Other studies show that SMAD signalling is increased in AE and that BMP2 signalling can control FLG expression. In these studies, increasing BMP2 expression led to impaired epidermal FLG, Loricrin and Keratin expression. As our data suggests that p-SMAD 1/5 is more highly expressed in AE with a pronounced genetic FLG deficiency, we propose a positive feedback model of barrier impairment in AE in which reduced FLG expression increases BMP2 signalling, consequently reducing EDC and keratin expression, which further impairs the epidermal barrier.

Lycoperoside H, a Tomato Seed Saponin, Improves Epidermal Dehydration by Increasing Ceramide in the Stratum Corneum and Steroidal Anti-Inflammatory Effect.

Tomatoes are widely consumed, however, studies on tomato seeds are limited. In this study, we isolated 11 compounds including saponins and flavonol glycosides from tomato seeds and evaluated their effects on epidermal hydration. Among the isolated compounds, tomato seed saponins (10 µM) significantly increased the mRNA expression of proteins related to epidermal hydration, including filaggrin, involucrin, and enzymes for ceramide synthesis, by 1.32- to 1.91-fold compared with the control in HaCaT cells. Tomato seed saponins (10 µM) also decreased transepidermal water loss by 7 to 13 g/m2·h in the reconstructed human epidermal keratinization (RHEK) models. Quantitative analysis of the ceramide content in the stratum corneum (SC) revealed that lycoperoside H (1–10 µM) is a promising candidate to stimulate ceramide synthesis via the upregulation of ceramide synthase-3, glucosylceramide synthase, and β-glucocerebrosidase, which led to an increase in the total SC ceramides (approximately 1.5-fold) in concert with ceramide (NP) (approximately 2-fold) in the RHEK models. Evaluation of the anti-inflammatory and anti-allergic effects of lycoperoside H demonstrated that lycoperoside H is suggested to act as a partial agonist of the glucocorticoid receptor and exhibits anti-inflammatory effects (10 mg/kg in animal test). These findings indicate that lycoperoside H can improve epidermal dehydration and suppress inflammation by increasing SC ceramide and steroidal anti-inflammatory activity.

Cystatin-B Negatively Regulates the Malignant Characteristics of Oral Squamous Cell Carcinoma Possibly Via the Epithelium Proliferation/Differentiation Program.

Disturbance in the proteolytic process is one of the malignant signs of tumors. Proteolysis is highly orchestrated by cysteine cathepsin and its inhibitors. Cystatin-B (CSTB) is a general cysteine cathepsin inhibitor that prevents cysteine cathepsin from leaking from lysosomes and causing inappropriate proteolysis. Our study found that CSTB was downregulated in both oral squamous cell carcinoma (OSCC) tissues and cells compared with normal controls. Immunohistochemical analysis showed that CSTB was mainly distributed in the epithelial structure of OSCC tissues, and its expression intensity was related to the grade classification. A correlation analysis between CSTB and clinical prognosis was performed using gene expression data and clinical information acquired from The Cancer Genome Atlas (TCGA) database. Patients with lower expression levels of CSTB had shorter disease-free survival times and poorer clinicopathological features (e.g., lymph node metastases, perineural invasion, low degree of differentiation, and advanced tumor stage). OSCC cell models overexpressing CSTB were constructed to assess the effects of CSTB on malignant biological behaviors and upregulation of CSTB inhibited cell proliferation, migration, and invasion in vitro. Weighted gene correlation network analysis (WGCNA) and gene set enrichment analysis (GSEA) were performed based on the TCGA data to explore potential mechanisms, and CSTB appeared to correlate with squamous epithelial proliferation-differentiation processes, such as epidermal cell differentiation and keratinization. Moreover, in WGCNA, the gene module most associated with CSTB expression (i.e., the brown module) was also the one most associated with grade classification. Upregulation of CSTB promoted the expression levels of markers (LOR, IVL, KRT5/14, and KRT1/10), reflecting a tendency for differentiation and keratinization in vitro. Gene expression profile data of the overexpressed CSTB cell line were obtained by RNA sequencing (RNA-seq) technology. By comparing the GSEA enrichment results of RNA-seq data (from the OSCC models overexpressing CSTB) and existing public database data, three gene sets (i.e., apical junction, G2/M checkpoint, etc.) and six pathways (e.g., NOTCH signaling pathway, glycosaminoglycan degradation, mismatch repair, etc.) were enriched in the data from both sources. Overall, our study shows that CSTB is downregulated in OSCC and might regulate the malignant characteristics of OSCC via the epithelial proliferation/differentiation program.

Gremlin 2 suppresses differentiation of stem/progenitor cells in the human skin.

IntroductionThe skin is comprised of various kinds of cells and has three layers, the epidermis, dermis and subcutaneous adipose tissue. Stem cells in each tissue duplicate themselves and differentiate to supply new cells that function in the tissue, and thereby maintain the tissue homeostasis. In contrast, senescent cells accumulate with age and secrete senescence-associated secretory phenotype (SASP) factors that impair surrounding cells and tissues, which lowers the capacity to maintain homeostasis in each tissue. Previously, we found Gremlin 2 (GREM2) as a novel SASP factor in the skin and reported that GREM2 suppressed the differentiation of adipose-derived stromal/stem cells. In the present study, we investigated the effects of GREM2 on stem cells in the epidermis and dermis.MethodsTo examine whether GREM2 expression and the differentiation levels in the epidermis and dermis are correlated, the expressions of GREM2, stem cell markers, an epidermal differentiation marker Keratin 10 (KRT10) and a dermal differentiation marker type 3 procollagen were examined in the skin samples (n = 14) randomly chosen from the elderly where GREM2 expression level is high and the individual differences of its expression are prominent. Next, to test whether GREM2 affects the differentiation of skin stem cells, cells from two established lines (an epidermal and a dermal stem/progenitor cell model) were cultured and induced to differentiate, and recombinant GREM2 protein was added.ResultsIn the human skin, the expression levels of GREM2 varied among individuals both in the epidermis and dermis. The expression level of GREM2 was not correlated with the number of stem cells, but negatively correlated with those of both an epidermal and a dermal differentiation markers. The expression levels of epidermal differentiation markers were significantly suppressed by the addition of GREM2 in the three-dimensional (3D) epidermis generated with an epidermal stem/progenitor cell model. In addition, by differentiation induction, the expressions of dermal differentiation markers were induced in cells from a dermal stem/progenitor cell model, and the addition of GREM2 significantly suppressed the expressions of the dermal differentiation markers.ConclusionsGREM2 expression level did not affect the numbers of stem cells in the epidermis and dermis but affects the differentiation and maturation levels of the tissues, and GREM2 suppressed the differentiation of stem/progenitor cells in vitro. These findings suggest that GREM2 may contribute to the age-related reduction in the capacity to maintain skin homeostasis by suppressing the differentiation of epidermal and dermal stem/progenitor cells.

Strength performance with buckling analysis of Intermediate filaments by consideration nonlocal parameters

Protein structures, that form intermediate filaments (IFs) was first found by an experiment known as the computerized analysis of amino acid sequence of a human epidermal keratin derived from cloned cDNAs. This study is made by the application of Euler beam theory. The buckling of intermediate filaments is studied keeping the nonlocal effects under consideration. It is observed that the nonlocal parameter has a great impact on the dynamics of intermediate filaments. The buckling behavior of intermediate filaments is investigated with different four conditions like as simply supported, clamped, cantilever and propped cantilever beam. Also the effect of critical bucking force is seen for different strengths of nonlocal parameter as 1,2,3,4.

A Case Series of Disseminated Porokeratosis

Porokeratosis is an autosomal dominant disorder of epidermal keratinization resulting from abnormal expansion of latent clones following chronic ultraviolet exposure or immunosuppression. Various clinical and morphological variants of porokeratosis are present, among which disseminated superficial actinic porokeratosis (DSAP) is the most common subtype located predominantly on the sun exposed areas, whereas disseminated superficial porokeratosis (DSP) is present both on the sun exposed and sun protected areas including oral mucosa and genitalia. Porokeratosis is characterized clinically by annular plaques with atrophic center and thready border and histologically by the presence of cornoid lamella. DSAP may be missed because of its inconspicuous nature in dark skinned individuals and may sometimes be mistaken for actinic keratoses in sun-damaged skin. Here, we report a case series of five patients with disseminated porokeratosis with varied presentations.

A case of squamous cell carcinoma arising in porokeratosis of Mibelli

Background: Porokeratosis is an uncommon disorder of epidermal keratinisation. Characteristic features include hyperkeratotic lesions with an atrophic centre and raised wall-like border, and the pathognomonic histological finding of a coronoid lamella.1 Malignant transformation into squamous, bowenoid or basal cell carcinoma rarely has been reported in all major variants.2 Aims: To describe a case of squamous cell carcinoma arising in porokeratosis of Mibelli. Methods: A 73-year-old man presented for routine skin malignancy surveillance with a new, asymptomatic lesion within a porokeratosis of Mibelli on his right calf, clinically suspicious for squamous cell carcinoma. His history included multiple non-melanoma skin cancers and one previous melanoma in situ. No other lesions typical for porokeratosis were found on examination. Histopathological examination of the lesion confirmed moderately differentiated squamous cell carcinoma arising in background changes of porokeratosis. The lesion was completely excised within a week of biopsy. Results and conclusions: Porokeratosis is a premalignant condition, however malignant transformation is rare.1 It is hypothesised that chromosomal instability and reduced immune surveillance with overexpression of p53 can contribute to the development of cutaneous malignancy within porokeratoses.2 Risk factors for malignancy include ionising radiation, sun exposure, immunosuppression, long history of the lesion and large size of the porokeratosis.3 This case adds to the existing literature surrounding malignant transformation of porokeratoses and highlights the importance of regular skin surveillance in affected patients.

Obesity accelerates hair thinning by stem cell-centric converging mechanisms.

Obesity is a worldwide epidemic that predisposes individuals to many age-associated diseases, but its exact effects on organ dysfunction are largely unknown1. Hair follicles-mini-epithelial organs that grow hair-are miniaturized by ageing to cause hair loss through the depletion of hair follicle stem cells (HFSCs)2. Here we report that obesity-induced stress, such as that induced by a high-fat diet (HFD), targets HFSCs to accelerate hair thinning. Chronological gene expression analysis revealed that HFD feeding for four consecutive days in young mice directed activated HFSCs towards epidermal keratinization by generating excess reactive oxygen species, but did not reduce the pool of HFSCs. Integrative analysis using stem cell fate tracing, epigenetics and reverse genetics showed that further feeding with an HFD subsequently induced lipid droplets and NF-κB activation within HFSCs via autocrine and/or paracrine IL-1R signalling. These integrated factors converge on the marked inhibition of Sonic hedgehog (SHH) signal transduction in HFSCs, thereby further depleting lipid-laden HFSCs through their aberrant differentiation and inducing hair follicle miniaturization and eventual hair loss. Conversely, transgenic or pharmacological activation of SHH rescued HFD-induced hair loss. These data collectively demonstrate that stem cell inflammatory signals induced by obesity robustly represses organ regeneration signals to accelerate the miniaturization of mini-organs, and suggests the importance of daily prevention of organ dysfunction.

Constitutive Hedgehog/GLI2 signaling drives extracutaneous basaloid squamous cell carcinoma development and bone remodeling.

Uncontrolled activation of the Hedgehog (Hh) signaling pathway, operating through GLI transcription factors, plays a central role in the pathogenesis of cutaneous basal cell carcinoma and contributes to the development of several malignancies arising in extracutaneous sites. We now report that K5-tTA;tetO-Gli2 bitransgenic mice develop distinctive epithelial tumors within their jaws. These tumors consist of large masses of highly proliferative, monomorphous, basaloid cells with scattered foci of keratinization and central necrosis, mimicking human basaloid squamous cell carcinoma (BSCC), an aggressive upper aerodigestive tract tumor. Like human BSCC, these tumors express epidermal basal keratins and differentiation-specific keratins within squamous foci. Mouse BSCCs express high levels of Gli2 and Hh target genes, including Gli1 and Ptch1, which we show are also upregulated in a subset of human BSCCs. Mouse BSCCs appear to arise from distinct epithelial sites, including the gingival junctional epithelium and epithelial rests of Malassez, a proposed stem cell compartment. Although Gli2 transgene expression is restricted to epithelial cells, we also detect striking alterations in bone adjacent to BSCCs, with activated osteoblasts, osteoclasts and osteal macrophages, indicative of active bone remodeling. Gli2 transgene inactivation resulted in rapid BSCC regression and reversal of the bone remodeling phenotype. This first-reported mouse model of BSCC supports the concept that uncontrolled Hh signaling plays a central role in the pathogenesis of a subset of human BSCCs, points to Hh/GLI2 signaling as a potential therapeutic target and provides a powerful new tool for probing the mechanistic underpinnings of tumor-associated bone remodeling.

The “spade sign” as a pathognomonic histopathologic feature of acne keloidalis: Analysis of 33 cases of cicatricial alopecia

To the Editor: Historically, the specific diagnosis of cicatricial alopecia using histology alone has remained elusive or impossible.1Mirmirani P. Willey A. Headington J.T. Stenn K. McCalmont T.H. Price V.H. Primary cicatricial alopecia: histopathologic findings do not distinguish clinical variants.J Am Acad Dermatol. 2005; 52: 637-643Abstract Full Text Full Text PDF PubMed Scopus (115) Google Scholar Acne keloidalis (AK) is a form of primary cicatricial alopecia, characterized by a mixed (lymphocytic and neutrophilic) infiltrate centered in the follicular isthmus. With time, there is thinning of the isthmic follicular epithelium and, eventually, clinically keloidal scarring associated with a foreign body granulomatous reaction, that is secondary to follicular destruction. Patients with AK exhibit features overlapping with other forms of alopecia.2Olsen E.A. Bergfeld W.F. Cotsarelis G. et al.Summary of North American Hair Research Society (NAHRS)-sponsored workshop on cicatricial alopecia, Duke University Medical Center, February 10 and 11, 2001.J Am Acad Dermatol. 2003; 48: 103-110Abstract Full Text Full Text PDF PubMed Scopus (291) Google Scholar In their recent AK series, Cheng et al3Cheng A.Y. Lee C.N. Hsieh F.N. et al.“Spade sign” and inflammation/fibrosis limited to the upper and mid-dermis as the pathognomonic features of acne keloidalis.J Dermatol. 2020; 47: 41-46Crossref PubMed Scopus (3) Google Scholar proposed that the spade sign (SS) is a pathognomonic histopathologic feature. They defined the SS as a spade-shaped space (resembling the spade symbol in playing cards) created by the dilated and thinned follicular epithelium in the lower isthmus. They also coined the term “balloon sign” (BS) as a variant, identical to SS, except for its round shape. The required presence of trichilemmal keratinization is characterized by the presence of isthmic follicular keratinocytes with pale eosinophilic cytoplasm and by abrupt keratinization, forming compact eosinophilic orthokeratin. To evaluate the sensitivity and specificity of the SS in a clinically relevant differential diagnosis, we performed a case control study to search for the SS in a spectrum of clinically confirmed cases of cicatricial alopecia from the teaching files of the senior author (Dr Fung). The vertical sections of hematoxylin-eosin–stained specimens were analyzed for the presence of the SS or BS. Thirty-three specimens from different patients were assessed. The diagnoses included AK (9 patients), folliculitis decalvans (6 patients), central centrifugal cicatricial alopecia (4 patients), dissecting cellulitis (4 patients), lichen planopilaris (6 patients), frontal fibrosing alopecia (2 patients), traction alopecia (1 patient), and discoid lupus (1 patient). The SS was found in 3 (3/9, 33%) AK specimens (Fig 1). Two specimens had the SS and BS in different affected follicles, whereas the third case had only the SS. The SS or BS was not present in the other cases. Upon comparing AK with all other forms of cicatricial alopecia, the sensitivity and specificity of the SS or BS for AK was found to be 33% and 100%, respectively. A single structure in 1 case of frontal fibrosing alopecia was classified as “pseudo-SS.” Although the follicular epithelium was dilated and thinned, it was located superficially and contained basket-weave orthokeratin. This superficial milia-type plugging, containing basophilic orthokeratin, may be seen in patients with frontal fibrosing alopecia and should not be confused with the SS (Fig 2).Fig 2Pseudospade sign or pseudo-balloon sign in a case of frontal fibrosing alopecia. The more superficial location of this structure is associated with epidermal keratinization in its superior portion, including a granular layer and loose, basophilic orthokeratin content, as is characteristic of comedones, milia, and epidermal inclusion cysts. (Original magnification: ×100).View Large Image Figure ViewerDownload Hi-res image Download (PPT) Our study suggests that the SS or BS is a highly specific feature of AK. Cheng et al3Cheng A.Y. Lee C.N. Hsieh F.N. et al.“Spade sign” and inflammation/fibrosis limited to the upper and mid-dermis as the pathognomonic features of acne keloidalis.J Dermatol. 2020; 47: 41-46Crossref PubMed Scopus (3) Google Scholar also identified the SS or BS in exactly 33% (5/15) of their cases. The low sensitivity of the SS may reflect the fact that the SS or BS may only be appreciated during subacute AK, prior to follicular destruction. Although we have tended to regard AK and folliculitis decalvans as very similar histologically, we did not encounter SS in our folliculitis decalvans cases. Whether this represents an artifact of insufficient numbers of cases or a true difference in diagnostic specificity warrants further study. Our source of cases may represent a limitation because the teaching cases might have been biased toward more representative features than randomly selected cases. In summary, our findings support the fact that the SS is a highly specific or pathognomonic histopathologic feature of AK. Although the absence of the SS does not argue against AK, the presence of the SS supports its diagnosis. None disclosed. The authors thank Dr María Rashidi Springall, PhD, for assistance with the statistical analysis.

Heparin-Binding Protein 17/Fibroblast Growth Factor-Binding Protein-1 Knockout Inhibits Proliferation and Induces Differentiation of Squamous Cell Carcinoma Cells.

Simple SummaryFibroblast growth factor (FGF) plays an important role in tumor growth by inducing angiogenesis in addition to promoting the proliferation of squamous cell carcinoma (SCC) and oral squamous cell carcinoma (OSCC) cells. Heparin-binding protein 17/fibroblast growth factor-binding protein-1 (HBp17/FGFBP-1) purified from A431 cell-conditioned media based on its capacity to bind to FGF-1 and FGF-2 is recognized as a pro-angiogenic molecule as a consequence of its interaction with FGF-2. In this study, we have examined the functional role of HBp17/FGFBP-1 in A431 and HO-1-N-1 cells using the CRISPR/Cas9 technology. Our results showed that HBp17/FGFBP-1 knockout inhibited cell proliferation, colony formation, and cell motility compared to control. The amount of FGF-2 was decreased in culture medium conditioned by HBp17/FGFBP-1 knockout cells compared to control. We performed cDNA/protein expression analysis followed by Gene Ontology and protein–protein interaction analysis. The results demonstrate that both gene and protein expression related to epidermal development, cornification, and keratinization were upregulated in HBp17/FGFBP-1-knockout A431 and HO-1-N-1 cells.Heparin-binding protein 17/fibroblast growth factor-binding protein-1 (HBp17/FGFBP-1) has been observed to induce the tumorigenic potential of epithelial cells and is highly expressed in oral cancer cell lines and tissues. It is also recognized as a pro-angiogenic molecule because of its interaction with fibroblast growth factor (FGF)-2. In this study, we examined the functional role of HBp17/FGFBP-1 in A431 and HO-1-N-1 cells. Originally, HBp17/FGFBP-1 was purified from A431 cell-conditioned media based on its capacity to bind to FGF-1 and FGF-2. We isolated and established HBp17/FGFBP-1-knockout (KO)-A431 and KO-HO-1-N-1 cell lines using the clusters of regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) gene editing technology. The amount of FGF-2 secreted into conditioned medium decreased for A431-HBp17-KO and HO-1-N-1-HBp17-KO cells compared to their WT counterparts. Functional assessment showed that HBp17/FGFBP-1 KO inhibited cell proliferation, colony formation, and cell motility in vitro. It also inhibited tumor growth in vivo compared to controls, which confirmed the significant difference in growth in vitro between HBp17-KO cells and wild-type (WT) cells, indicating that HBp17/FGFBP-1 is a potent therapeutic target in squamous cell carcinomas (SCC) and oral squamous cell carcinomas (OSCC). In addition, complementary DNA/protein expression analysis followed by Gene Ontology and protein–protein interaction (PPI) analysis using the Database for Visualization and Integrated Discovery and Search Tool for the Retrieval of Interacting Genes/Proteins showed that both gene and protein expression related to epidermal development, cornification, and keratinization were upregulated in A431-HBp17-KO and HO-1-N-1-KO cells. This is the first discovery of a novel role of HBp17/FGFBP-1 that regulates SCC and OSCC cell differentiation.