Suprabasal Layers Research Articles

FC19 A global investigation of the aryl hydrocarbon receptor pathway reveals multiple levels of dysregulation amenable for therapeutic targeting in psoriasis

Abstract The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor and environmental sensor with homeostatic roles in the skin. We and others have shown that physiological AHR activation ameliorates inflammation in psoriasis models, leading to the development of the first-in-class AHR-modulating drug, Tapinarof, for mild-to-moderate psoriasis. The AHR pathway is regulated at multiple levels, including through the cytochrome P450 1 (CYP1) enzymes, which degrade AHR ligands providing critical negative feedback. Here we aim to deeply investigate the AHR pathway to identify dysfunctional checkpoints for therapeutic intervention in psoriasis. We performed a multi-model investigation in the blood and skin of White moderate-to-severe psoriasis patients (n = 51), not receiving systemic therapy, and age/sex/ethnicity-matched healthy volunteers (n = 28), assessing AHR ligand and precursor availability in serum, AHR and CYP1A1 bulk and spatial mRNA and protein in blood and skin, in vitro modulation of AHR expression in normal human epidermal keratinocytes (NHEK) by psoriasis-relevant cytokines, and CYP1 enzymatic activity. Serum levels of the ligand precursor tryptophan were significantly decreased in psoriasis patients (P < 0.001; n = 19) vs. healthy (n = 19). AHR mRNA expression was significantly decreased in psoriasis blood (P < 0.01; n = 30) and psoriasis lesional (PsL; P < 0.01; n = 17) skin vs. healthy, while CYP1A1 mRNA expression did not differ in blood but showed a downward trend in PsL (P = 0.0546; n = 16). While AHR and CYP1A1 protein were mostly co-expressed in the suprabasal skin layers, AHR mRNA predominantly localized in the basal layer in PsL (n = 5) compared with a more widespread expression in healthy skin (n = 7), with a reduction in AHR positive cells in the PsL dermis (P < 0.05). TNF (P < 0.001) and IFN-γ (P < 0.0001) significantly upregulated AHR mRNA in NHEK (n = 4). In vitro culture of skin epidermal sheets with the AHR agonist FICZ significantly upregulated CYP1A1 mRNA expression in healthy (q < 0.05; n = 8) and psoriasis epidermis (q < 0.05; n = 7); however, CYP1 enzymatic activity was not increased by AHR ligation in PsL. In contrast, FICZ-induced CYP1 enzymatic activity was enhanced in Th17 cells from the same patients (P = 0.0535; n = 8). Finally, exposure of NHEK to a psoriasis inflammatory cocktail containing TNF, IL-23 and IL-17A resulted in a significant reduction in induced CYP1 enzymatic activity (n = 3, P < 0.05), suggesting a potential mechanism for the lack of ligand-induced activity in PsL. Taken together, our data show that there is a multi-level dysregulation of the AHR pathway in psoriasis and suggests a failure of multiple pathway checkpoints that could be further targeted to restore AHR’s beneficial effects on skin.

Deletion of Fgfr2 in Ductal Basal Epithelium With Tamoxifen Induces Obstructive Meibomian Gland Dysfunction.

Fibroblast growth factor receptor 2 (Fgfr2) is crucial for the homeostasis of meibomian gland (MG). However, the role of Fgfr2 in MG ductal epithelial progenitors remains to be delineated. Herein, we created a new transgenic mouse model with conditional deletion of Fgfr2 from MG ductal progenitors and investigated the cell-specific role in the pathogenesis of obstructive meibomian gland dysfunction. Peritoneal injection of tamoxifen (TAM) at 50 µg/gm for three consecutive days was performed to induce conditional deletion of Fgfr2 in two-month-old Krt5Fgfr2CKO or Krt5Fgfr2CKO-mTmG mice. Phenotypes of MG after Fgfr2 deletion were monitored by meibography, lipid staining, and immunostaining against keratin-6a in MG whole mounts. Lineage tracing of the Krt5+ progenitors of MG and biomarkers for ductal differentiation and proliferation were also examined by immunostainings. The Krt5Fgfr2CKO mice developed extensive ductal occlusion and acinar atrophy at day 10 after TAM administration. Robust thickening of ductal epithelium with abnormal differentiation and proliferation of ductal basal meibocytes were observed in the MGs of Krt5Fgfr2CKO mice. In Krt5Fgfr2CKO-mTmG mice, the Krt5+ progenitors and its progeny were labeled by EGFP after Fgfr2 depletion by TAM with evident expansion of the suprabasal and superficial layers of MG ductal epithelium when compared with the controls. Our results substantiated the crucial role of Fgfr2 in homeostasis of the MG ductal epithelium. Deletion of Fgfr2 affects the MG ductal basal progenitors by impacting the differentiation of ductal meibocytes and the maintenance of acinar meibocytes, which are likely the underlying pathogenesis of obstructive MGD.

SOX-10 and Melan-A Immunostaining in Areas of Focal Acantholytic Dyskeratosis and Epidermolytic Hyperkeratosis Within Dysplastic Nevi Biopsies: An Observational Study.

Focal acantholytic dyskeratosis (FAD) and epidermolytic hyperkeratosis (EHK) are common incidental epidermal histologic findings within dysplastic nevi biopsies. We evaluate whether areas of FAD and EHK within dysplastic nevi biopsies stain with immunostains used to characterize melanocytic neoplasms. In this case series, a natural language search of histopathology reports from our institution in the past year (2020-2021) identified dysplastic nevus biopsies with concurrent FAD and/or EHK. Tissue samples were examined for positive melanocytic immunostaining with SOX-10 and Melan-A in areas of FAD and EHK. Out of 32 biopsies, 20 of 26 FAD specimens (76.9%) and 2 of 6 EHK specimens (33.3%) showed unexpected suprabasal layer staining with a melanocytic marker that did not correspond to definitively identified melanocytes on the H&E-stained sections. The immunohistochemical staining of FAD and EHK was observed in 2 forms: nonspecific background staining or "true" staining (ie, seemed nuclear on SOX-10 or cytoplasmic on Melan-A). This pilot examination provides evidence that areas of incidental FAD within dysplastic nevi biopsies demonstrate unexpected suprabasal layer staining with melanocytic markers. When dermatopathologists evaluate melanocytic neoplasms with melanocytic markers, it is possible the presence of incidental FAD could lead to over diagnosing pagetoid scatter within these lesions. This study is a proof of concept with mild to moderately dysplastic nevi that do not typically incur the use of melanocytic stains; however, the implication of this unexpected staining pattern would be important when using melanocytic markers on borderline melanocytic neoplasms that have incidental FAD. Close correlation with H&E is imperative to prevent misinterpretation in these cases.

Ultrastructure and immunohistochemistry of apteric skin in ratites and its epidermal soft cornification

An electron microscopy and immunohistochemistry study has been conducted to acquire comparative information on the structure of apteric skin in ratites, ostrich and emu. The epidermis is thin in the neck of both species and thicker in the dorsal region where acidic and neutral keratins are present in the viable epidermis and stratum corneum. The dermis in both species is mostly occupied by collagen fibrils that form large bundles, often organized in alternated layers in the deeper part of the dermis. Numerous collagen fibrils contact the basement membrane of the epidermis. Sparse tactile Meissner or Krause sensilli are present among the thick collagen bundles. The ostrich epidermis in the dorsal skin is thicker than in the neck, with a columnar basal layer, 3–5 intermediate suprabasal layers and a thick corneous layer. The epidermis of the neck in emu is very thin, featuring two-three narrow cell layers above a flat basal layer and a relatively thick corneous layer. Basal and suprabasal keratinocytes contain lipid droplets and small keratin bundles but no keratohyalin accumulates in pre-corneous cells. The thin corneocytes form a multilayered corneous layer. Loricrine is present in pre-corneous and corneous layers while CBPs, formerly indicated as beta-keratins, are absent in apteric epidermis.

Analysis of Immunohistochemical Expression of Bcl-2 in Cases of Psoriasis and Psoriasiform Dermatitis.

Introduction Psoriasis involves rapid cell growth and abnormal differentiation of skin cells. Dysregulation of apoptosis has been proposed in the pathogenesis of psoriasis. The role of Bcl-2 as an anti-apoptotic proteinin pathogenesis has not been studied in detail in these cases.Our study aims to evaluate the expression of Bcl-2 in different skin compartments in psoriasis and psoriasiform dermatitis cases. Materials and methodology An analytical cross-sectional study was performed using paraffin blocks of psoriasis and psoriasiform dermatitis patients between 2022 and 2023. For light microscopy screening, sections were initially stained with hematoxylin and eosin stains. In further sections, a primary antibody against Bcl-2 was applied. The level of Bcl-2 expression in keratinocytes of supra-basal and basalepidermal layers and dermal lymphocytes was evaluated using a scoring system. Results Sixty patients, 30 with psoriasis and 30 with psoriasiform dermatitis were included. Among the histopathological features, parakeratosis (p - 0.038), Munro's microabscesses (p - 0.001), supra-papillary plate thinning (p - 0.004), and increased dermal vasculature (p - 0.001) were significantly associated with psoriasis when compared with psoriasiform dermatitis. Most psoriatic lesions had hypogranulosis whereas it was alternating hypo and hypergranulosis in psoriasiform dermatitis (p - 0.001). Acanthosis was regular in psoriasis lesions (p - 0.036). Bcl-2 expression was seen in dermal lymphocytes in all psoriasis and psoriasiform lesions with significantly stronger positive expression compared to basal and supra-basal layers. Psoriasis cases demonstrated more significant Bcl-2 positivity in dermal lymphocytes and basal layers than psoriasiform dermatitis cases. Conclusion Bcl-2 has stronger expression in dermal lymphocytes and basal layers than supra-basal layers, which comply with the proposed pathogenesis. Increased Bcl-2 expression in psoriasis cases compared with other psoriasiform dermatitis lesions implies the more chronic and recurrent nature of the disease.

PAX6-WNK2 Axis Governs Corneal Epithelial Homeostasis.

Limbal stem/progenitor cells (LSCs) continuously proliferate and differentiate to replenish the corneal epithelium and play a vital role in corneal function and normal vision. A previous study revealed that paired box 6 (PAX6) is a master transcription factor involved in determining the fate of corneal epithelial cells (CECs). However, the molecular events downstream of PAX6 remain largely unknown. In this study, we aimed to clarify the regulation network of PAX6 in driving CEC differentiation. An air-liquid culture system was used to differentiate LSCs into mature CECs. Specific targeting PAX6 short-hairpin RNAs were used to knock down PAX6 in LSC. RNA sequencing (RNA-seq) was used to analyze shPAX6-transfected CECs and CEC differentiation-associated genes to identify the potential downstream targets of PAX6. RNA-seq analysis, quantitative real-time PCR, and immunofluorescence staining were performed to clarify the function of WNK lysine deficient protein kinase 2 (WNK2), a downstream target of PAX6, and its relationship with corneal diseases. WNK2 expression increased during CEC differentiation and decreased upon PAX6 depletion. The distribution of WNK2 was specifically limited to the central corneal epithelium and suprabasal layer of the limbus. Knockdown of WNK2 impaired the expression of CEC-specific markers (KRT12, ALDH3A1, and CLU), disrupted the corneal differentiation process, and activated the terms of keratinization, inflammation, and cell proliferation, consistent with PAX6-depleted CEC and published microbial keratitis. Thus, aberrant expression of WNK2 was linked to corneal ulcers. As a downstream target of PAX6, WNK2 plays an essential role in corneal epithelial cell differentiation and maintenance of corneal homeostasis.

Immunoexpression of metallothionein, Ki‐67 and PCNA in dermoid and epidermoid cysts of the oral cavity

AbstractObjectiveTo assess the immunoexpression of metallothionein and cell proliferation markers (Ki‐67 and PCNA) in a series of cases comprising four dermoid cysts and six epidermoid cysts of the oral cavity.Materials and MethodsThe percentages of nuclear and/or cytoplasmic staining in the basal and suprabasal layers of the cysts' epithelial lining were assessed.ResultsThis study included six males and four females, with a mean age of 33.1 years. The floor of the mouth was affected in 40% of the cases. The expression of metallothionein, Ki‐67, and PCNA was observed in all cases examined. For both lesions, the basal layer exhibited higher cytoplasmic and nuclear/cytoplasmic expression of metallothionein. Dermoid cysts exhibited higher expression of Ki‐67 and PCNA compared to epidermoid cysts in both basal and suprabasal layers, with a more pronounced expression in the suprabasal layers.ConclusionsOur results indicate that metallothionein is present in the epithelial lining of both dermoid and epidermoid cysts of the oral cavity. The cell proliferation indices observed in both conditions reflect their benign nature and slow growth.

Epidermal cell proliferation and differentiation in the beak of tadpoles of Rana dalmatina

AbstractEpidermal cell proliferation and differentiation during formation of the beak in tadpoles of Rana dalmatina. Acta Zoologica (Stockolm). The beak utilized in tadpoles of R. dalmatina for crushing vegetables is formed of cornified cell layers. A row of large wedge‐like cells forms a central pile that produces the sharp corneous lamina of the beak. The labial and oral surfaces of the beaks also accumulate corneous material during proliferation and differentiation of keratinocytes from the epidermis to form a sheath around the central corneous cells. Corneocytes are shed during the growth of tadpoles. Electron microscopy reveals that keratin and mucus granules are main components of these keratinocytes. Electron‐dense organelles of unknown composition and with inside lamellae are also present. Using immunohistochemistry after post‐injection of 5BrdU, a marker of cell proliferation, the main timing of formation of the beak has been determined. After 2–5 h from injection, labelled nuclei of keratinocytes are seen in the basal layer, and sparse suprabasal labelled nuclei are detected after 5 h. Labelled keratinocytes are seen in suprabasal layers at 2 days post‐injection. At 5 and 6 days labelled keratinocytes are present in central corneous cells and in the lateral shell of corneocytes forming the labial and oral beak sides. Shedding a complete stratum corneum likely takes more days, but this depends on feeding usage.

Myosin II mediates Shh signals to shape dental epithelia via control of cell adhesion and movement.

The development of ectodermal organs begins with the formation of a stratified epithelial placode that progressively invaginates into the underlying mesenchyme as the organ takes its shape. Signaling by secreted molecules is critical for epithelial morphogenesis, but how that information leads to cell rearrangement and tissue shape changes remains an open question. Using the mouse dentition as a model, we first establish that non-muscle myosin II is essential for dental epithelial invagination and show that it functions by promoting cell-cell adhesion and persistent convergent cell movements in the suprabasal layer. Shh signaling controls these processes by inducing myosin II activation via AKT. Pharmacological induction of AKT and myosin II can also rescue defects caused by the inhibition of Shh. Together, our results support a model in which the Shh signal is transmitted through myosin II to power effective cellular rearrangement for proper dental epithelial invagination.

Endoscopic diagnosis and treatment of lichen planus of the esophagus

Purpose of the study: to attract the attention of endoscopists and doctors of other specialties to the problem of diagnosis and treatment of lichen planus of the esophagus. Materials and methods. From January 2010 to December 2023, lichen planus was the cause of dysphagia in 7 of 17 patients with unexplained cicatricial strictures of the esophagus. Our own experience and literature data on endoscopic semiotics and treatment of lichen planus of the esophagus are presented. Results of the study. Lichen planus is most often localized in the upper third of the esophagus and is accompanied by a narrowing of the esophageal lumen. The mucosa is hyperemic, dull, with areas of epithelial detachment, erosions, and fibrin deposits. All 7 patients had grade 2-3 esophageal strictures with isolated esophageal involvement (3) or oral involvement (4). Morphological changes were nonspecific: ulcerations, granulation tissue and fibrosis of the underlying layers, atrophy and thinning of the epidermis, acanthosis. Only in 2 cases apoptotic Civatte bodies were detected in the suprabasal layer, which is a characteristic feature of lichen planus of the esophagus. All patients underwent courses of endoscopic bougienage, supplemented by intramural injections of triamcinolone. This manipulations led to stabilization of the esophageal lumen at 10-15 mm without a tendency to restenosis. Conclusion. Further experience is needed to determine optimal treatment strategies, but it is critical to pay particular attention to symptom assessment in patients with skin disorders and odynophagia or dysphagia. These actions will facilitate an earlier diagnosis of lichen planus of the esophagus and increase the effectiveness of endoscopic treatment.

Influence of peripheral nerve system on proliferation and migration of keratinocytes on site of the wound edges

AIM: to assess proliferation and migration of keratinocytes at the nonhealing edges of neuropathic wounds.MATERIALS AND METHODS: 25 patients with neuropathic ulcers and 5 patients without diabetes with decubitus were enrolled. Diabetic foot (DF) patients were underwent to standard treatment including debridement, atraumatic dressing, offloading, antibacterial therapy if it needs. Severity of peripheral neuropathy was assessed according to the NDS scale. Histo­logical (hematoxylin and eosin) and immunohistochemical (Ki-67 , α7nAChR markers) examination of wound edge were done during treatment (0, 10, 24 days).RESULTS: All patients have severe neuropathy according to NDSm (>8). The average size of DF ulcers before and on 10th day of treatment was of 4 cm2 and 2,5 cm2, respectively (p<0,004). Neuropathic ulcers were characterized by hyperproliferative epidermis. Mitotically active keratinocytes reside throughout the suprabasal layers. Ki-67 expressed all layers of the epidermis, but a greater staining density was detected in the basal layer. The density of a7nAChR-positive cells increased from 0 to 24 days (p=0,031).THE CONCLUSION: The data shows that neuropathy is one of the possible mechanisms of keratinocyte cell cycle disruption: proliferative activity and ability to migrate. Identification of new signaling pathways regulating the physiological repair of tissues and the study of their disorders in diabetes mellitus opens the prospect of developing an optimal therapeutic strategy.

ASH2L Mediates Epidermal Differentiation and Hair Follicle Morphogenesis through H3K4me3 Modification

The processes of epidermal development in mammals are regulated by complex molecular mechanisms, such as histone modifications. Histone H3 lysine K4 methylation mediated by COMPASS (complex of proteins associated with Set1) methyltransferase is associated with gene activation, but its effect on epidermal lineage development remains unclear. Therefore, we constructed a mouse model of specific ASH2L (COMPASS methyltransferase core subunit) deletion in epidermal progenitor cells and investigated its effect on the development of mouse epidermal lineage. Furthermore, downstream target genes regulated by H3K4me3 were screened using RNA sequencing combined with Cleavage Under Targets and Tagmentation sequencing. Deletion of ASH2L in epidermal progenitor cells caused thinning of the suprabasal layer of the epidermis and delayed hair follicle morphogenesis in newborn mice. These phenotypes may be related to the reduced proliferative capacity of epidermal and hair follicle progenitor cells. ASH2L depletion may also lead to depletion of the epidermal stem cell pools in late mouse development. Finally, genes related to hair follicle development (Shh, Edar, and Fzd6), Notch signaling pathway (Notch2, Notch3, Hes5, and Nrarp), and ΔNp63 were identified as downstream target genes regulated by H3K4me3. Collectively, ASH2L-dependent H3K4me3 modification served as an upstream epigenetic regulator in epidermal differentiation and hair follicle morphogenesis in mice.

Abstract 761: The relationship between ANGPTL4 and epidermal malignant transformation

Abstract High body mass index (BMI) is a risk factor for several types of cancers. Although epidemiology suggests obesity is negatively associated with non-melanoma skin cancer (NMSC), bariatric surgery has been shown to reduce the risk, suggesting a possible role of adipose tissue in the initiation and promotion of skin cancer. To gain mechanistic insight into how adipose tissue drives cutaneous carcinogenesis, we cultured non-tumorigenic mouse keratinocytes (JB6 P+ cells) with or without factors released from murine visceral adipose tissue (mFTF) and performed RNA-Sequencing. Published work demonstrated mFTF induces anchorage-independent cell growth, a surrogate marker for malignant transformation. Transcriptomic analysis demonstrated a significant induction of Angptl4 mRNA in JB6 P+ cells cultured with mFTF for 3 and 8 hours compared to the vehicle-treated cells. ANGPTL4 is an endogenous inhibitor of lipoprotein lipase that modulates free fatty acid delivery to adipose tissue and oxidative tissues such as muscle and liver. The C-terminal protein demonstrates tumor-associated activities such as angiogenesis, metastasis, protection against anoikis, and enhancement of cell survival. Therefore, we hypothesized that the induction of this gene promotes malignant transformation. RNA-seq data was validated in multiple cell models, including primary keratinocytes with human adipose tissue. Immunohistochemistry was used to assess ANGPTL4 expression in 37 actinic keratosis (pre-malignant) and cutaneous squamous cell carcinoma (cSCC) from patients with different BMIs (18.6 - 49.5). Notably, ANGPTL4 was only observed in the suprabasal epidermal layers in normal skin. For samples containing both lesional and perilesional skin, there was an increase in ANGPTL4 expression in the lesional epidermis relative to the normal perilesional skin. Furthermore, ANGPTL4 expression increased from transition to actinic keratosis to cSCC in situ, suggesting that ANGTL4 is induced during malignant transformation as observed in our pre-clinical models. Interestingly, once cSCC developed an invasive component, ANGTPL4 expression was lost in the invasive keratinocytes but persisted in the in situ component. There was no association between ANGPTL4 expression and BMI in lesional tissue. These data suggest that targeting ANTPLT4 may be a novel therapy for the prevention of skin cancer and that ANGPTL4-high patients or cancer patients with obesity may be a critical demographic for potential risk assessment or therapeutic intervention. Future studies will determine the impact of knocking out ANGTPL4 in our models of malignant transformation. Citation Format: Nat Ato Yawson, Jonathan D. Diedrich, Karen T. Liby, Jesse Veenstra, Jamie Jenna Bernard. The relationship between ANGPTL4 and epidermal malignant transformation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 761.

In situ distribution of markers for stemness, quiescence, proliferation and differentiation in the human cornea and limbus

Aims/Purpose: Identify the distribution of the most commonly used markers for stemness, quiescence, proliferation, and differentiation in limbal compartments such as human limbal epithelial crypts, posterior and anterior limbus, as well as the central and posterior cornea.Methods: Corneal‐limbal biopsies from cadaver human donors (n = 3) embedded in paraffin were proceeded for immunohistochemistry fluorescence and examined for stemness/progenitor markers (p63α, SOX9, ABCG2, N‐cadherin), proliferation markers (ki‐67), quiescence marker (CEBPD), differentiation markers (CX43, KRT3, KRT12, KRT13), and epithelial marker (E‐cadherin). Images were obtained by Zeiss Axio Observer. Fluorescent images were obtained using the Zeiss Axio Imager M1 fluorescence microscope (ZEISS, Oberkochen, Germany).Results: The stemness/progenitor markers p63α and SOX9 were found in basal and suprabasal cells of limbal epithelial crypts and limbal epithelium, whereas the ABCG2 and N‐cadherin were exclusive for limbal basal epithelium in all limbal structures. Proliferation marker Ki‐67 was most abundant in suprabasal layers of the limbus and rarely found in the posterior cornea, while absent in anterior cornea. Quiescence marker CEBPD was positive in the basal cells of both, limbus and cornea. Differentiation markers KRT3 and KRT12 were positive in the whole cornea and intermediate and superficial layers in anterior and posterior limbus, while rarely present in limbal epithelial crypts. However, CX43 was staining almost all suprabasal layers in the limbus as well as basal and suprabasal layers in the cornea. KRT13 was exclusive for superficial layer of the anterior and posterior limbus layers staining conjunctival cells.Conclusions: Here we identify the localization of the most common markers used to determine the stemness, quiescence, proliferation, and differentiation status to unravel the in situ distribution of these markers in the limbal epithelial crypts, posterior and anterior limbus, as well as the central and posterior cornea. The study accumulated new knowledge about the distribution of these markers and the corneal‐limbal organization.

Immunohistochemical Expression of CK14 and Bcl-2 in Odontogenic Keratocyst and Its Variants.

Odontogenic keratocysts (OKCs) are aggressive cystic jaw lesions with a high epithelial turnover rate and increased propensity for recurrence. Sometimes, the characteristic histopathological features of OKCs are either completely lost or seen focally due to previous marsupialization or inflammation. This research aimed to determine whether specific patterns of CK14 and Bcl-2 staining could assist in diagnosing OKCs with altered epithelial features and provide clues in elucidating their aggressive nature. CK14 expression was restricted to basal and suprabasal layers near satellite cysts and in areas showing subepithelial split. The entire epithelial lining showed CK14 expression in areas of inflammation and after marsupialization. The typical basal/suprabasal staining of Bcl-2 was lost in areas of inflammation and intensity is decreased in OKCs after marsupialization. These new findings could offer a hint into the biological nature and pathogenesis of OKCs. Because of its therapeutic consequences and high recurrence rate, proper recognition and diagnosis are essential for treatment planning.

Three atypical/malignant onychopapillomas in a 52-case series with immunohistochemical study.

Onychopapilloma (OP) is a benign tumor of the nail. Haneke reported one case of malignant OP in 2021. No systematic immunohistochemistry study has been conducted on OP. The aim of our study was to identify possible malignant OP in our series of OP and to describe the immunohistochemical expression of p16, p53, and Ki67 in typical and atypical/malignant ones. Ninety-one cases were available for pathological review. Immunohistochemical analysis could be performed on 52 cases. In 88 of 91 cases, the diagnosis of OP was confirmed. Three atypical/malignant cases were observed. No OP expressed p16. A normal p53 expression was observed in two thirds of the cases, an abnormal increased p53 expression in one third, including the three atypical cases. A normal Ki67 expression was observed in 84% of the cases, an abnormal Ki67 expression with focal heterogeneous expression in the suprabasal layers in 6% and in all suprabasal cell layers in 10%, including the three atypical cases. The diagnosis of atypical/malignant OP may be underestimated. The expression of Ki67 and p53 in these tumors differs from the expression observed in conventional OP. The absence of p16 expression confirms that human papillomavirus does not play a role in the etiopathogenesis of OP.

Agent-based approach for elucidating the release from collective arrest of cell motion in corneal epithelial cell sheet

Changes in cell fluidity have been observed in various cellular tissues and are strongly linked to biological phenomena such as self-organization. Recent studies suggested variety of mechanisms and factors, which are still being investigated. This study aimed to investigate changes in cell fluidity in multi-layered cell sheets, by exploring the collective arrest of cell motion and its release in cultures of corneal epithelial cells. We constructed mathematical models to simulate the behaviors of individual cells, including cell differentiation and time-dependent changes in cell-cell connections, which are defined by stochastic or kinetic rules. Changes in cell fluidity and cell sheet structures were expressed by simulating autonomous cell behaviors and interactions in tissues using an agent-based model. A single-cell level spatiotemporal analysis of cell state transition between migratable and non-migratable states revealed that the release from collective arrest of cell motion was initially triggered by a decreased ability to form cell-cell connections in the suprabasal layers, and was propagated by chain migration. Notably, the disruption of cell-cell connections and stratification occurred in the region of migratable state cells. Hence, a modeling approach that considers time-dependent changes in cell properties and behavior, and spatiotemporal analysis at the single-cell level can effectively delineate emergent phenomena arising from the complex interplay of cells.

Expression profiles of glucocorticoid-inducible proteins in human papilloma virus-related oropharyngeal squamous cell carcinoma.

Human papillomavirus virus-related oropharyngeal squamous cell carcinoma (HPV-OPSCC) comprises a significant portion of head and neck cancers. Several glucocorticoid-inducible proteins play important roles in pathogenesis of some cancers but their status and roles in HPV-OPSCC remain elusive; these include the glucocorticoid-induced leucine zipper (GILZ), Annexin-A1 and serum glucocorticoid-regulated kinase-1 (SGK-1). We determined expression profiles of these proteins, using immunohistochemistry, in archived biopsy samples of patients diagnosed with HPV-OPSCC; samples of non-cancer oral lesions (e.g., hyperkeratosis) were used as controls. GILZ staining was primarily confined to nuclei of all tissues but, in HPV-OPSCC specimens, neoplastic cells exhibiting mitosis displayed prominent cytoplasmic GILZ expression. On the other hand, nuclear, cytoplasmic and membranous Annexin-A1 staining was observed in suprabasal cell layers of control specimens. A noted feature of the HPV-OPSCC specimens was few clusters of matured and differentiated nonbasaloid cells that showed prominent nuclear and cytoplasmic Annexin-A1 staining while the remainder of the tumor mass was devoid of staining. Cytoplasmic and nuclear staining for SGK-1 was prominent for control than PV-OPSCC specimens while staining for phosphorylated SGK-1 (pSGK-1; active) was prominent for cell membrane and cytoplasm of control specimens but HPV-OPSCC specimens showed mild and patchy nuclear and cytoplasmic staining. Semi-quantitative analysis of GILZ immunostaining indicated increased staining area but similar normalized staining for HPV-OPSCC compared to control specimens. By contrast, staining area and normalized staining were reduced for other proteins in HPV-OPSCC than control specimens. Our collective observations suggest differential cellular localization and expression of glucocorticoid-inducible proteins in HPV-OPSCC suggestive of different functional roles in pathogenesis of this condition.

Biomimetic human skin model patterned with rete ridges

Rete ridges consist of undulations between the epidermis and dermis that enhance the mechanical properties and biological function of human skin. However, most human skin models are fabricated with a flat interface between the epidermal and dermal layers. Here, we report a micro-stamping method for producing human skin models patterned with rete ridges of controlled geometry. To mitigate keratinocyte-induced matrix degradation, telocollagen–fibrin matrices with and without crosslinks enable these micropatterned features to persist during longitudinal culture. Our human skin model exhibits an epidermis that includes the following markers: cytokeratin 14, p63, and Ki67 in the basal layer, cytokeratin 10 in the suprabasal layer, and laminin and collagen IV in the basement membrane. We demonstrated that two keratinocyte cell lines, one from a neonatal donor and another from an adult diabetic donor, are compatible with this model. We tested this model using an irritation test and showed that the epidermis prevents rapid penetration of sodium dodecyl sulfate. Gene expression analysis revealed differences in keratinocytes obtained from the two donors as well as between 2D (control) and 3D culture conditions. Our human skin model may find potential application for drug and cosmetic testing, disease and wound healing modeling, and aging studies.

Mammalian esophageal stratified tissue homeostasis is maintained distinctively by the epithelial pluripotent p63+Sox2+ and p63-Sox2+ cell populations.

Self-renewing, damage-repair and differentiation of mammalian stratified squamous epithelia are subject to tissue homeostasis, but the regulation mechanisms remain elusive. Here, we investigate the esophageal squamous epithelial tissue homeostasis in vitro and in vivo. We establish a rat esophageal organoid (rEO) in vitro system and show that the landscapes of rEO formation, development and maturation trajectories can mimic those of rat esophageal epithelia in vivo. Single-cell RNA sequencing (scRNA-seq), snapshot immunostaining and functional analyses of stratified "matured" rEOs define that the epithelial pluripotent stem cell determinants, p63 and Sox2, play crucial but distinctive roles for regulating mammalian esophageal tissue homeostasis. We identify two cell populations, p63+Sox2+ and p63-Sox2+, of which the p63+Sox2+ population presented at the basal layer is the cells of origin required for esophageal epithelial stemness maintenance and proliferation, whereas the p63-Sox2+ population presented at the suprabasal layers is the cells of origin having a dual role for esophageal epithelial differentiation (differentiation-prone fate) and rapid tissue damage-repair responses (proliferation-prone fate). Given the fact that p63 and Sox2 are developmental lineage oncogenes and commonly overexpressed in ESCC tissues, p63-Sox2+ population could not be detected in organoids formed by esophageal squamous cell carcinoma (ESCC) cell lines. Taken together, these findings reveal that the tissue homeostasis is maintained distinctively by p63 and/or Sox2-dependent cell lineage populations required for the tissue renewing, damage-repair and protection of carcinogenesis in mammalian esophagi.