Suprabasal Layers Research Articles

Oral epithelial IL-22/STAT3 signaling licenses IL-17-mediated immunity to oral mucosal candidiasis.

Oropharyngeal candidiasis (OPC; thrush) is an opportunistic infection caused by the commensal fungus Candida albicans Interleukin-17 (IL-17) and IL-22 are cytokines produced by type 17 lymphocytes. Both cytokines mediate antifungal immunity yet activate quite distinct downstream signaling pathways. While much is now understood about how IL-17 promotes immunity in OPC, the activities of IL-22 are far less well delineated. We show that, despite having similar requirements for induction from type 17 cells, IL-22 and IL-17 function nonredundantly during OPC. We find that the IL-22 and IL-17 receptors are required in anatomically distinct locations within the oral mucosa; loss of IL-22RA1 or signal transducer and activator of transcription 3 (STAT3) in the oral basal epithelial layer (BEL) causes susceptibility to OPC, whereas IL-17RA is needed in the suprabasal epithelial layer (SEL). Transcriptional profiling of the tongue linked IL-22/STAT3 not only to oral epithelial cell proliferation and survival but also, unexpectedly, to driving an IL-17-specific gene signature. We show that IL-22 mediates regenerative signals on the BEL that replenish the IL-17RA-expressing SEL, thereby restoring the ability of the oral epithelium to respond to IL-17 and thus to mediate antifungal events. Consequently, IL-22 signaling in BEL "licenses" IL-17 signaling in the oral mucosa, revealing spatially distinct yet cooperative activities of IL-22 and IL-17 in oral candidiasis.

Oral epithelial IL-22/STAT3 signaling licenses IL-17-mediated immunity to oral mucosal candidiasis

Abstract Oropharyngeal candidiasis (OPC) is an opportunistic infection of the oral mucosa caused by the commensal fungus Candida albicans. IL-17 and IL-22 both mediate antifungal immunity yet activate distinct downstream signaling pathways. While much is known about IL-17-dependent immunity in OPC, the activities of IL-22 are less well delineated. We show that induction of Il22 is independent of Dectin-1, CARD9 and aryl hydrocarbon receptor (AhR) and is driven by IL-23 and the C. albicans pore forming peptide candidalysin. Despite similar induction requirements and cellular sources, IL-22 and IL-17 function non-redundantly during OPC and exert opposing roles in neutrophil recruitment. The IL-22 and IL-17 receptors are required in anatomically distinct locations; loss of IL-22RA1 in the oral basal epithelial layer (BEL) but not the suprabasal epithelial layer (SEL) causes susceptibility to OPC, whereas IL-17RA is needed in the SEL. Our data reveal that IL-22 is a major activator of STAT3 in the BEL during OPC. Moreover, loss of STAT3 in the BEL but not the SEL renders mice susceptible to OPC. Transcriptional profiling of RNASeq data linked IL-22/STAT3 to oral epithelial cell proliferation and survival, but also, unexpectedly, to driving an IL-17 gene signature. We show that IL-22 acts on the BEL to replenish the IL-17RA-expressing SEL, thereby restoring the ability of the oral epithelium to respond to IL-17. Consequently, IL-22 signaling in BEL ‘licenses’ IL-17R signaling in the oral epithelium, revealing spatially distinct yet cooperative activities of IL-22 and IL-17 in oral candidiasis. This work also suggests that oral thrush in Jobs’ syndrome patients may be caused by STAT3 impairments in the oral epithelium, not just Th17 cells.

ATP2A2 SINE Insertion in an Irish Terrier with Darier Disease and Associated Infundibular Cyst Formation.

A 4-month-old female Irish Terrier presented with a well demarcated ulcerative and crusting lesion in the right ear canal. Histological analysis revealed epidermal hyperplasia with severe acantholysis affecting all suprabasal layers of the epidermis, which prompted a presumptive diagnosis of canine Darier disease. The lesion was successfully treated by repeated laser ablation of the affected epidermis. Over the course of three years, the dog additionally developed three dermal nodules of up to 4 cm in diameter that were excised and healed without complications. Histology of the excised tissue revealed multiple infundibular cysts extending from the upper dermis to the subcutis. The cysts were lined by squamous epithelium, which presented with abundant acantholysis of suprabasal keratinocytes. Infundibular cysts represent a novel finding not previously reported in Darier patients. Whole genome sequencing of the affected dog was performed, and the functional candidate genes for Darier disease (ATP2A2) and Hailey-Hailey disease (ATP2C1) were investigated. The analysis revealed a heterozygous SINE insertion into the ATP2A2 gene, at the end of intron 14, close to the boundary of exon 15. Analysis of the ATP2A2 mRNA from skin of the affected dog demonstrated a splicing defect and marked allelic imbalance, suggesting nonsense-mediated decay of the resulting aberrant transcripts. As Darier disease in humans is caused by haploinsufficiency of ATP2A2, our genetic findings are in agreement with the clinical and histopathological data and support the diagnosis of canine Darier disease.

Determination of Ki-67 expression in oral leukoplakia in snuff users and non-users in Khyber Pakhtunkhwa province of Pakistan.

Objectives: The aim of the article was to evaluate Ki-67 expression in oral leukoplakia in snuff users and non-users. Study Design: Descriptive Cross sectional study. Setting: At different hospitals of Khyber Pakhtunkhwa province. Period: From August 2016 –March 2017. Material & Methods: Clinically diagnosed and histopathologically confirmed cases of oral leukoplakia in snuff users and non-users 30 cases each were immunohistochemically examined and percentage expression of nuclear Ki-67 was evaluated by a semi quantitative method in basal, parabasal and suprabasal layers of the lining epithelium. Results: The relationship of expression of Ki-67 in parabasal and suprabasal layers of affected epithelium in snuff users was found to be statistically significant with a p value of 0.007 and 0.002 respectively. Conclusion: The present study concludes that the proliferative index is high in snuff users as compared to non-users which can be a factor for malignant transformation.

Chemopreventive effect of olive oil in experimentally induced hamster buccal pouch epithelial dysplasia (Randomized control trial)

The progression of tumor depends on the level of Bcl-2 which protects the cells from undergoing apoptosis, and its level should be more than the level of the death inducer. So, our Aim: To investigate chemopreventive effect of olive oil in epithelial alteration which induced in hamster buccal pouch. Methods: Epithelial dysplasia will occur by the application of DMBA on alternative days for 8 weeks on hamster buccal pouch. Hematoxylin and Eosin (H&E) and Streptavidin-biotin immunoperoxidase staining techniques were used to detect the expression of Bcl-2 in three groups (G1 negative control or normal group, G2 DMBA group and G3 olive oil chemoprevention group). Evaluation of the immunostaining was done by using computer image analyzer system. Results: H & E stained histological section in G1 with normal mucosa of HBP intact, and continuous epithelium of thin keratinized stratified squamous epithelium while in G2 there were incidence of severe epithelial dysplasia with hyperkeratosis & G3 reduced dysplasia incidence and severity as compared to G2. Bcl-2 immunohistochemical expression in G1 in basal & suprabasal layers while in G2 & G3 located in all epithelial layers with statistically highly significant difference (P G1, G3) and (G3>G1). Conclusion: Olive oil plays an important role in reduction and prevention of transformation of normal oral epithelium into epithelial dysplasia. The liquid form of olive oil may be considered as a new line of chemoprevention in oral dysplasia and the Bcl-2 expression evidenced this reduction of abnormality in epithelial dysplasia.

Loss of Peptidyl‐Arginine Deiminase 1‐mediated Citrullination Drives Esophageal Epithelial Barrier Impairment in Allergic Inflammation

BackgroundCitrullination or deimination is a post‐translational modification in which neutral arginine residues are converted to positive citrulline by members of the peptidyl‐arginine deiminase (PADI) family. PADI1 is an esophageal enriched gene that is significantly downregulated in Eosinophilic Esophagitis (EoE), an eosinophilic‐driven chronic allergic inflammatory disorder characterized by reduced tissue differentiation and impaired esophageal epithelial barrier formation. While the role of PADI1 in deiminating structural proteins has been implicated in epithelial cell populations, including the skin, the functional significance and extent of PADI1‐mediated citrullination in allergic inflammation remains understudied.HypothesisHerein we hypothesize that the loss of PADI1‐mediated citrullination drives esophageal epithelial barrier impairment in allergic inflammation.MethodsPADI1 WT and KO EPC2 immortalized human esophageal epithelial cells generated by CRISPR‐Cas9 were grown in either monolayer or at Air‐Liquid Interface (ALI) to mimic esophageal differentiation. Transepithelial Electrical Resistance (TEER) measurements of EPC2 cells grown at ALI were measured as a function of barrier integrity. Transcriptional, protein and epigenetic analyses were conducted on EPC2 cells grown at ALI treated with or without IL‐13, a T‐cell derived cytokine known to induce responses involved in EoE. Immunofluorescence (IF) was used to visualize structural proteins and assess overall level of citrullination.ResultsPADI1 protein was found to be most highly expressed in the Esophageal Mucosa as compared to all other tissue types, specifically in the suprabasal layer of differentiated esophageal cells. PADI1 RNA expression was decreased eight‐fold (P < 0.0001) in esophageal biopsies of patients with EoE as compared to control patients. Treatment of EPC2 cells with IL‐13 (100 ng/ml) at confluence reduced PADI1 mRNA by three‐fold (P < 0.01). PADI1 KO cells demonstrate altered differentiation as assessed by decreased levels of citrullinated proteins and structural epithelial proteins, including filaggrin, involucrin, desmoglein‐1, E‐cadherin, and cornulin compared with wild‐type control cells.ConclusionOur data suggest that loss of PADI1‐mediated citrullination may drive esophageal epithelial barrier impairment in allergic inflammation.Support or Funding InformationThis work is supported by PHS Grant R01‐AI124355 and the Ohio Physiological Society.

The Molecular Anatomy of Mouse Skin during Hair Growth and Rest.

Skin homeostasis is orchestrated by dozens of cell types that together direct stem cell renewal, lineage commitment, and differentiation. Here, we use single-cell RNA sequencing and single-molecule RNA FISH to provide a systematic molecular atlas of full-thickness skin, determining gene expression profiles and spatial locations that define 56 cell types and states during hair growth and rest. These findings reveal how the outer root sheath (ORS) and inner hair follicle layers coordinate hair production. We found that the ORS is composed of two intermingling but transcriptionally distinct cell types with differing capacities for interactions with stromal cell types. Inner layer cells branch from transcriptionally uncommitted progenitors, and each lineage differentiation passes through an intermediate state. We also provide an online tool to explore this comprehensive skin cell atlas, including epithelial and stromal cells such as fibroblasts, vascular, and immune cells, to spur further discoveries in skin biology.

Epidermal structure and differentiation.

In this Primer, Moreci and Lechler follow the lifetime of an epidermal cell from its birth to its ultimate death, and detail how this journey is necessary for epidermal function.

WIF1 Suppresses the Generation of Suprabasal Cells in Acanthotic Skin and Growth of Basal Cell Carcinomas upon Forced Overexpression

We analyzed the role of WIF1 in normal and acanthotic epidermis of 12-O-tetradecanoylphorbol-13-acetate (TPA) or all-trans-retinoic acid (ATRA)-treated and basal cell carcinoma (BCC)-bearing mice. WIF1 protein is located in the follicular infundibulum and interfollicular epidermis (IFE) in murine back skin. Within the hyperplastic epidermis of TPA- or ATRA-treated or BCC-bearing murine skin, WIF1 and Keratin 10 overlap in Ki67⁻ suprabasal layers, while basal epidermal layers expressing Ki67, and BCCs expressing Wif1 mRNA, are free of WIF1 protein. This is similar in human skin, with the exception that WIF1 protein is found in single Ki67⁻ basal epidermal cells in normal skin and additionally in Ki67+ cells in acanthotic skin. Wif1-deficiency enhances acanthosis of the murine BCC-associated epidermis, which is accompanied by an increase of Ki67+ and of Sca-1+ basal cells. WIF1 overexpression in allografted BCC-derived keratinocytes prevents growth and keratinization, involving enhanced phosphorylation of protein kinase C and extracellular signal-regulated kinase 1 and arguably factors secreted by the invivo environment. In summary, WIF1 protein marks suprabasal layers in the normal IFE. It is also present in the epidermis overlaying BCCs where it diminishes proliferation of basal cells and production of differentiating suprabasal cells. In addition, WIF1 can prevent proliferation and keratinization of BCC-related keratinocytes.

Analysis of expression of p53, p63 and proliferating cell nuclear antigen proteins in odontogenic keratocyst: An immunohistochemical study.

Background:Odontogenic keratocyst (OKC) is a benign intraosseous lesions (within the jaw bone) of odontogenic origin that account for about 10% of jaw cysts. They are characterized by an aggressive behavior with a relatively high recurrence rate. Early diagnosis and follow-up of the patient with OKC is important because the possibility of such patient there is develop to other features of Nevoid basal cell carcinoma syndrome in future. Considering the roles and effects of p53, p63 and proliferating cell nuclear antigen (PCNA) in cells proliferation, this study was designed.Objectives:To understand the behavior of epithelial cells in pathogenesis and biological aspects of OKC in diagnosis.Materials and Methods:Immunohistochemical (IHC)technique was performed in 21 cases of OKCs.Results:Immunological stained p53 cells were mainly located in the suprabasal layers. p63 and PCNA-positive cells were found throughout the lining epithelium including basal and suprabasal cell layers. The intensity of staining was more in p63 and PCNA than the p53 expression of the cystic epithelial lining.Conclusions:It is possible that the biological behavior of OKCs may be related to the suprabasal proliferative compartment in the cystic epithelium as observed. These proteins may participate in the regulation of epithelial cell differentiation. Taken together, these data may favor tumerigenesis on OKCs.

Morphometric Analysis of Suprabasal Cell Layer in Oral Epithelial Dysplasia: A Computer-assisted Microscopic Study.

ABSTRACTBackground:Oral leukoplakia is the most common precancerous lesion. Various grading systems based on histological findings have been proposed for dysplasia. Recently, computer-assisted morphometric analysis has been established to reduce the interobserver and intraobserver variability during the histological grading of epithelial dysplasia. This study was undertaken to establish the morphometric changes in the suprabasal cell layer of different grades of oral epithelial dysplasia.Materials and Methods:Forty paraffin-embedded tissue sections (10 normal mucosa, 10 mild dysplasia, 10 moderate dysplasia, and 10 severe dysplasia cases) were stained using hematoxylin and eosin stain, and analyzed for cellular and nuclear morphometry using binocular microscope.Results:Our results showed that values of nuclear area, nuclear perimeter, nuclear volume density, and nuclear/cytoplasmic (N/C) ratio were increased gradually in dysplasia compared to control groups and the values were statistically significant (P = 0.001). Nuclear diameter and cellular area were increased in dysplasia when compared to control group (P = 0.001). Mild and moderate dysplasia showed decreased value of nuclear form factor compared to control group, whereas severe dysplasia showed highest value. A fair correlation was found when comparing histological grading and grouping based on nuclear area, nuclear perimeter, N/C ratio, and nuclear volume density.Conclusion:Nuclear features reflect cell behavior, and its morphometric analysis can be considered as a reliable tool for differentiating various grades of epithelial dysplasia.

An Immunohistochemical Study Showing Ki-67 as an Analytical Marker in Oral Malignant and Premalignant Lesions.

ABSTRACTIntroduction:Ki-67 is a nuclear protein. It is a proliferation marker that has an essential function in tumorigenesis due to its positive connection with tumor expansion.Aim:The aim of this study was to evaluate the articulation of Ki‑67 as prognostic marker in various grades of oral epithelial dysplasia (OED) and in oral squamous cell carcinoma (OSCC).Materials and Methods:A total of 100 histologically affirmed samples of normal oral mucosa (NOM), OED, and OSCC were divided into three groups—Group I (10 samples of normal oral mucosa), Group II (45 samples of OED), Group III (45 samples of OSCC). Routine hematoxylin and eosin and immunohistochemical staining with Ki-67 monoclonal antibody were carried out in all the samples.Results:Within Group I, articulation of Ki-67 was constrained to the basal layers. In Group II, cells showing positive expression of Ki-67 were available in the basal, suprabasal, and spinous layers. Cells showing positive expression of Ki-67 among well-differentiated OSCC were presented mainly in the periphery of the tumor nests; in moderately differentiated OSCC, cells were located in both peripheral and part of a center of the tumor nests; and in most cases of poorly differentiated OSCC, cells were diffused. Statistically significant difference in positive expression of Ki-67 was appreciated between three groups.Conclusion:Ki-67 antigen may perhaps be used as a marker for the histological reviewing of OED and OSCC. With the increase in the severity of OED, cells showing positive expression of Ki-67 also increased.

Desmosomes Pattern Cell Mechanics to Govern Epidermal Tissue Form and Function

The epidermis is a stratified epithelium in which structural and functional features are polarized across multiple cell layers. This type of polarity is essential for establishing the epidermal barrier, but how it is created and sustained is poorly understood. Previous work identified a role for the classical cadherin/filamentous-actin network in establishment of epidermal polarity. However, little is known about potential roles of the most prominent epidermal intercellular junction, the desmosome, in establishing epidermal polarity, in spite of the fact that desmosome constituents are patterned across the apical to basal cell layers. Here, we show that desmosomes and their associated intermediate filaments (IF) are key regulators of mechanical polarization in epidermis, whereby basal and suprabasal cells experience different forces that drive layer-specific functions. Uncoupling desmosomes and IF or specific targeting of apical desmosomes through depletion of the superficial desmosomal cadherin, desmoglein 1, impedes basal (stratification) and suprabasal (tight junction barrier) functions. Surprisingly, disengaging desmosomes from IF also uncouples stratification from differentiation, accelerating the expression of differentiation markers. Our data support a model in which the desmosome-IF network supports a reciprocally organized distribution of ErbB1/EGFR activity in the basal layer and mechanosensitive kinase ErbB2 activity in the suprabasal layer to ensure the proper spatiotemporal coordination of cell mechanics and the biochemical program of differentiation.

MELANOACANTHOMA OF THE BUCCAL MUCOSA

Oral melanoacanthoma (MA) is a rare pigmented lesion characterized by hyperplasia of spinous keratinocytes and dendritic melanocytes that usually affects the buccal mucosa, lip, palate, and gingiva of adult women. An otherwise healthy 58-year-old female patient presented a diffuse pigmented dark brown lesion on the right buccal mucosa measuring 5 cm in greatest diameter. The clinical differential diagnoses included melanocytic macule, melanocytic nevus, and melanoacanthoma. Gross features included a whitish soft tissue showing superficial pigmented deposits. The microscopic evaluation showed marked acanthosis of parakeratinized stratified squamous epithelium of the oral cavity, which was associated with heavily pigmented dendritic melanocytes in the basal and suprabasal layers of the epithelium. The lamina propria presented melanophages and lymphocytic infiltrate containing eosinophils. The biopsy site healed completely without complications. Oral clinicians and pathologists should consider oral melanoacanthoma in the clinical differential diagnosis of oral pigmented lesions.

Aggregatibacter actinomycetemcomitans Biofilm Reduces Gingival Epithelial Cell Keratin Expression in an Organotypic Gingival Tissue Culture Model.

Epithelial cells express keratins, which are essential for the structural integrity and mechanical strength of the cells. In the junctional epithelium (JE) of the tooth, keratins such as K16, K18, and K19, are expressed, which is typical for non-differentiated and rapidly dividing cells. The expression of K17, K4, and K13 keratins can be induced by injury, bacterial irritation, smoking, and inflammation. In addition, these keratins can be found in the sulcular epithelium and in the JE. Our aim was to estimate the changes in K4, K13, K17, and K19 expression in gingival epithelial cells exposed to Aggregatibacter actinomycetemcomitans. An organotypic gingival mucosa and biofilm co-culture was used as a model system. The effect of the biofilm after 24 h was assessed using immunohistochemistry. The structure of the epithelium was also studied with transmission electron microscopy (TEM). The expression of K17 and K19, as well as total keratin expression, decreased in the suprabasal layers of epithelium, which were in close contact with the A. actinomycetemcomitans biofilm. The effect on keratin expression was biofilm specific. The expression of K4 and K13 was low in all of the tested conditions. When stimulated with the A. actinomycetemcomitans biofilm, the epithelial contact site displayed a thick necrotic layer on the top of the epithelium. The A. actinomycetemcomitans biofilm released vesicles, which were found in close contact with the epithelium. After A. actinomycetemcomitans irritation, gingival epithelial cells may lose their resistance and become more vulnerable to bacterial infection.

Endocytosis of IgG, Desmoglein 1, and Plakoglobin in Pemphigus Foliaceus Patient Skin.

Pemphigus foliaceus (PF) is one of the two main forms of pemphigus and is characterized by circulating IgG to the desmosomal cadherin desmoglein 1 (DSG1) and by subcorneal blistering of the skin. The pathomechanism of blister formation in PF is unknown. Previously we have shown that PF IgG induces aggregation of DSG1, plakoglobin (PG), and IgG outside of desmosomes, what in immunofluorescence of PF patient skin visualizes as a granular IgG deposition pattern with a limited number of coarse IgG aggregates between cells. Here we have investigated the fate of these aggregates in skin and found that these are cleared by endocytosis. We performed double immunofluorescence staining on snap-frozen skin biopsies of six PF patients for the following molecules: IgG, the desmosomal proteins DSG1 and DSG3, desmocollins 1 and 3, PG, desmoplakin and plakophilin 3, and for the endosomal marker early endosomal antigen 1 and the lysosomal markers cathepsin D and lysosomal-associated membrane protein 1. Endosomes were present in all cells but did not make contact with the aggregates in the basal and suprabasal layers. In the higher layers they moored to the aggregates, often symmetrically from two adjacent cells, and IgG, DSG1, and PG were taken up. Finally these endosomes became localized perinuclear. Endocytosis was only observed in perilesional or lesional skin but not in non-lesional skin. Older immunoelectron microscopic studies have suggested that in PF skin endocytosis of detached desmosomes takes place but we found no other desmosomal proteins to be present in these endosomes. Double staining with cathepsin D and LAMP-1 revealed no overlap with IgG, DSG1, or PG suggesting that lysosomes have no role in the clearing process. Collectively, our results show that endocytosis is part of the pathogenic process in PF but that no detached desmosomes are taken up but instead the deposited IgG is taken up together with DSG1 and PG.

Symposium review: Determinants of milk production: Understanding population dynamics in the bovine mammary epithelium

The mammary gland undergoes distinct periods of growth, development, and secretory activity. During bovine lactation, a gradual decrease in the number of mammary epithelial cells largely accounts for the decline in milk production with advancing lactation. The net decline in cell number (approx. 50%) is due to cell death but is simultaneously accompanied by cell renewal. Although the rate of cell proliferation is slow, by the end of lactation most cells in the gland were formed after calving. Typically milking is terminated when cows are in the final 2 mo of pregnancy. This causes regenerative involution, wherein extensive cell replacement and mammary growth occurs. We hypothesized that replacement of senescent secretory cells and progenitor cells during the dry period increases milk yield in the next lactation. Analysis of global gene expression revealed networks and canonical pathways during regenerative involution that support cell turnover and mammary growth, and reflect oxidative stress, mitochondrial dysfunction, and endoplasmic reticulum (ER) stress. Immune responses consistent with influx of neutrophils, macrophages, and lymphocytes, and processes that support mammary differentiation and lactogenesis were also evident. Data also suggest that replication of stem and progenitor cells occurs during the dry period. Relying on long-term retention of bromodeoxyuridine-labeled DNA, we identified putative bovine mammary stem cells. These label-retaining epithelial cells (LREC) are in low abundance within mammary epithelium (<1%), predominantly estrogen receptor-negative, and localized in a basal or suprabasal layer of the epithelium. Analyses of gene expression in laser-microdissected LREC are consistent with the concept that LREC represent stem cells and progenitor cells, which differ in properties and location within the epithelial layer. We identified potential markers for these cells and have increased their number by infusing xanthosine through the teat canal of prepubertal heifers. Altering population dynamics of mammary stem and progenitor cells during the mammary cycle may be a means to increase efficiency of milk production.

Interferon Kappa Is Up-Regulated in Psoriasis and It Up-Regulates Psoriasis-Associated Cytokines in vivo.

PurposeThere is increased type I interferon signature in psoriasis patients. Interferon-kappa (IFN-κ) is a member of type I interferon family that is constitutively expressed by keratinocytes. In this study, we investigate whether IFN-κ is involved in psoriasis etiology.Patients and methodsTwenty healthy individuals, 20 psoriasis vulgaris patients and 10 atopic dermatitis (AD) were included for this study. Immunohistochemistry staining, normal human epidermal keratinocytes (NHEK) culture, Ca2Cl-induced differentiation, quantitative reverse transcription (qRT-PCR), ELISA and murine experiments were performed.ResultsWe found IFN-κ protein expression was extremely low in the epidermis of normal skin, but it was significantly increased in the suprabasal layers of epidermal keratinocytes in psoriatic skin lesions. However, its expression in the skin lesions of AD was similar to normal skin. Additionally, IFN-κ protein was detected in sera from psoriasis patients, but not in sera from normal subjects and AD. We further investigated the regulation of IFNk gene expression in NHEK. We found that IFNk was significantly induced by types of nucleic acid pathogen recognition receptor (PRR) agonists in NHEK. While its expression was significantly induced by itself and IFN-γ, it was inhibited by type 2 immunity cytokines IL4 and IL13; other inflammatory cytokines including IL1 super-family members and IL17A did not alter its expression. Addition of recombinant IFN-κ did not affect keratinocytes differentiation. Using the murine experimental model, we demonstrated that subcutaneous administration of recombinant IFN-κ did not increase skin thickness, but significantly increased the transcription of TNFA and IL17A in mice skin.ConclusionIncreased IFN-κ in psoriasis may be caused by injured cells-released nucleic acids, increased IFN-γ and self-activation. Its enhancement may contribute to the etiology of the disease by enhancing TNFA and IL17A gene expression.

Rab25 Deficiency Perturbs Epidermal Differentiation and Skin Barrier Function in Mice.

Rab25, a member of the Rab11 small GTPase family, is central to achieving cellular polarity in epithelial tissues. Rab25 is highly expressed in epithelial cells of various tissues including breast, vagina, cervix, the gastrointestinal tract, and skin. Rab25 plays key roles in tumorigenesis, mainly by regulating epithelial differentiation and proliferation. However, its role in skin physiology is relatively unknown. In this study, we demonstrated that Rab25 knock-out (KO) mice show a skin barrier dysfunction with high trans-epidermal water loss and low cutaneous hydration. To examine this observation, we investigated the histology and epidermal differentiation markers of the skin in Rab25 KO mice. Rab25 KO increased cell proliferation at the basal layer of epidermis, whereas the supra-basal layer remained unaffected. Ceramide, which is a critical lipid component for skin barrier function, was not altered by Rab25 KO in its distribution or amount, as determined by immunohistochemistry. Notably, levels of epidermal differentiation markers, including loricrin, involucrin, and keratins (5, 14, 1, and 10) increased prominently in Rab25 KO mice. In line with this, depletion of Rab25 with single hairpin RNA increased the expression of differentiation markers in a human keratinocyte cell line, HaCaT. Transcriptomic analysis of the skin revealed increased expression of genes associated with skin development, epidermal development, and keratinocyte differentiation in Rab25 KO mice. Collectively, these results suggested that Rab25 is involved in the regulation of epidermal differentiation and proliferation.

Computerized Evaluation of the Immunoexpression of Ki-67 Protein in Odontogenic Keratocyst and Dentigerous Cyst.

Evaluation and comparison of odontogenic keratocysts and detigerous cysts immunoexpression and immunostaining intensities of Ki-67 antigen by assessing the whole extent of the epithelium (all epithelium layers in combination) and each layer individually. Ki-67 immunoexpression was evaluated in 15 odontogenic keratocysts and 6 dentigerous cysts using automated methods and the Aperio Technologies Inc. computer system. No statistically significant differences were observed in immunoexpression nor in immunostaining intensities between both lesions. Also, no statistically significant differences were found between odontogenic keratocysts from maxilla versus mandible nor primary versus recurrent. However, odontogenic keratocyst showed a significantly higher cellular proliferation index in the suprabasal layers compared to the basal layer. Assessment of the cellular proliferation index through a computerized system enabled the evaluation of all epithelial tissue without field selection. The increased Ki-67 immunoexpression in suprabasal layers of odontogenic keratocyst suggests a different biological behavior and more aggressive proliferation potential when compared to dentigerous cyst. The same result was found in recurrent odontogenic keratocysts when compared with primary ones. The odontogenic keratocysts of the maxilla and mandible have similar Ki-67 immunoexpression. The evaluation of cellular proliferation only by immunohistochemical analysis with Ki-67 antigen does not provide enough data to elucidate the biological behavior of odontogenic keratocyst.