Epidermal Hyperproliferation Research Articles

318 The long non-coding RNA LINC00958 is overexpressed in psoriasis epidermis and induces keratinocyte proliferation

Psoriasis is a common, chronically relapsing inflammatory skin disease characterized by epidermal hyperproliferation. LncRNAs are >200 nucleotide long transcripts, which do not code for protein but possess diverse regulatory functions. To date, little is known about the contribution of lncRNAs to psoriasis. Here, we identified lncRNAs with altered expression using transcriptomic profiling on epidermal cells sorted from psoriasis and healthy skin. LINC00958 was identified as a lncRNA overexpressed in keratinocytes from psoriasis skin lesions, and confirmed by RT-qPCR and single molecule in situ hybridization.

323 A Novel, Stress-Responsive and Clinically Predictive Humanized Mouse Model of Atopic Dermatitis: Autologous Th2-Polarized Lymphocytes Suffice to Induce Characteristic Lesions in Healthy Non-Atopic Human Skin Xenotransplants In Vivo

Clinically relevant in vivo models for atopic dermatitis (AD) are needed, in which the minimal signals required for AD induction in human skin can be defined and candidate therapeutics explored. Here, we report a novel humanized AD mouse model that uses split-thickness skin from healthy, non-atopic female human donors xenotransplanted onto SCID/beige mice and injected with autologous, Th2-polarized PBMCs. After intradermal injection of PBMCs preincubated only with IL-2, IL-4 and LPS, the xenotransplants develop a phenocopy of human AD lesions, including epidermal hyperplasia, hyperproliferation, erythema, and skin barrier impairment (reduced filaggrin and claudin-1 expression, altered corneocyte nanotexture [atomic force miocroscopy]).

089 3D Computational Modelling of Immune Interaction and Epidermal Homeostasis in Psoriasis

Psoriasis is a chronic inflammatory skin disease characterised by immune cytokine stimulated epidermal hyperproliferation. Previous modelling studies of psoriatic skin have been limited to 2D models and lacked cell-cell interactions. We developed the first 3D agent-based model of epidermal cell dynamics to gain insights into complex spatio-temporal changes, in particular how immune cytokine stimuli induces hyperproliferation altering epidermal cell division and structure in psoriasis. The agent-based model was implemented in state-of-art LAMMPS open-source, massively parallel simulator.

CCN1 upregulates IL-36 via AKT/NF-κB and ERK/CEBP β-mediated signaling pathways in psoriasis-like models.

Psoriasis is a chronic skin disorder characterized by epidermal keratinocyte hyperproliferation and inflammatory infiltration. CCN1 (also termed CYR61 or cysteine-rich angiogenic inducer 61) is an extracellular matrix-associated protein that is involved in multiple physiological functions. In psoriasis, we recently demonstrated that the overexpression of CCN1 promoted keratinocyte proliferation and activation. Furthermore, CCN1 was highly expressed in psoriatic skin lesions from psoriasis vulgaris patients. Here, we dissect the underlying molecular mechanism in imiquimod (IMQ) and interleukin (IL)-23-induced psoriasis-like models. Our results demonstrate that CCN1 can significantly upregulate IL-36 production in the murine skin of IMQ and IL-23-induced psoriasis-like models. Injection of CCN1-neutralizing antibody improved epidermal acanthosis and significantly reduced IL-36 production in vivo. These results suggest that CCN1 can be a critical upstream pro-inflammatory factor in psoriasis. In primary normal human epidermal keratinocytes, we demonstrated that CCN1 can selectively induced the production of IL-36α and IL-36γ through the activation of the protein kinase B (AKT)/nuclear factor kappa light chain enhancer of activated B cells (NF-κB) and extracellular-regulated kinase (ERK)/CCAAT/enhancer binding protein β (CEBPβ) signaling pathways via integrin receptor α6β1 in vitro. Our results suggest that targeting CCN1 can be a potential therapeutic strategy for psoriasis.

008 Smad7 dampened IL22 signaling-induced inflammation through IL22RA2 upregulation

IL22 signaling plays a critical role in the pathogenesis of skin inflammatory diseases such as psoriasis and atopic dermatitis. Smad7 is a transforming growth factor β (TGFβ) inhibitor consisting of an N-terminal domain, a C-terminal domain, and a linker region harboring a PY motif. Smad7 transgene expression in Keratin 5 (K5)+ keratinocytes attenuated K5.TGFβ1 transgene-induced psoriatic inflammation. The downstream mechanistic players and functional domains of Smad7 that mediates its anti-inflammatory properties and whether the anti-inflammatory function of Smad7 applies to other skin conditions remain to be determined. Here, we showed that mice expressing K5.Smad7, but not the N-terminal domain of Smad7, caused resistance to imiquimod (IMQ)-induced dermatitis compared to their wildtype littermates. Further, we generated a truncated Smad7 protein with C-terminal Smad7 and PY motif (PYC-Smad7) fused with the cell-penetrating Tat peptide (Tat-PYC-Smad7). Topical application of Tat-PYC-Smad7 significantly attenuated IMQ-induced psoriatic inflammation, 2,4-dinitrofluorobenzene-induced atopic dermatitis, and tape-stripping-induced skin inflammation. RNA sequencing analysis and spatial phenotyping with multiplex immunofluorescence identified that Tat-PYC-Smad7 not only mitigated TGFβ and NFκβ signaling but alleviated inflammation-induced epidermal hyperproliferation, neutrophil, macrophage and T-cell infiltration, angiogenesis, and STAT3 activation. These anti-inflammatory effects of Tat-PYC-Smad7 were mediated by Tat-PYC-Smad7 upregulation of IL22RA2, a negative regulator of IL22/STAT3 signaling. Upregulation of IL22RA2 by Tat-PYC-Smad7 was dependent upon transcriptional factor C/EBP-β, which binds to IL22RA2 promotor in cells expressing PYC-Smad7. Thus, PYC-Smad7 contains the functional domain of Smad7 to dampen multiple IL-22-dependent pro-inflammatory signaling pathways and Smad7-based Tat protein is a potential therapeutic agent for treating skin inflammatory diseases.

ANGPTL4 Regulates Psoriasis via Modulating Hyperproliferation and Inflammation of Keratinocytes.

Background: Psoriasis is characterized by keratinocyte proliferation and massive inflammatory leukocytes infiltration, affecting 0.14%–1.99% of the world’s population. Our aim was to identify novel potential therapeutic strategies for psoriasis. Methods: Weighted gene co-expression network analysis (WGCNA) was performed to identify gene modules that were closely related to psoriasis based on the GSE30999 dataset, which contained expression data from 85 patients with moderate-to-severe psoriasis. Then, angiopoietin-like 4 (ANGPTL4), one of the most related hub genes, was selected for in vitro and in vivo functional assays. In our experiments, imiquimod (IMQ)-induced psoriasiform dermatitis in mice and human keratinocytes (HaCaT) cells were used to study the potential roles and mechanisms of ANGPTL4 in psoriasis. Results: WGCNA analysis revealed the turquoise module was most correlated with psoriasis, and ANGPTL4 is one of the most related hub genes that significantly upregulated in psoriasis lesions compared with non-lesional skin. Consistent with the bioinformatic analysis, the expression of ANGPTL4 was significantly upregulated in IMQ-induced psoriasiform skin of mice. Exogenous recombinant ANGPLT4 protein treatment could promote the proliferation and induce the expression of inflammatory cytokines in HaCaTs, whereas silencing of ANGPTL4 effectively inhibited these effects. Then we demonstrated that recombinant ANGPTL4 protein exacerbated psoriasiform inflammation and epidermal hyperproliferation in vivo. Mechanismly, extracellular signal-regulated kinase 1/2 (ERK1/2) and signal transducer and activator of transcription 3 (STAT3) pathways were involved in ANGPTL4-mediated regulation of proliferation and inflammation. Conclusion: We found ANGPTL4 was significantly increased in IMQ-induced psoriasiform skin of mice. ANGPTL4 could promote keratinocyte proliferation and inflammatory response via ERK1/2 and STAT3 dependent signaling pathways in psoriasis.

Abstract 1313: IL-17RC, but not PLK4 inhibitor centrinone, plays a critical role in the development of skin papilloma and psoriasis in mouse models

Abstract Introduction: Hyperproliferation of epidermis is a histopathological hallmark of skin disorders, such as skin cancers and psoriasis. Polo-like kinase 4 (PLK4) is a master regulator of centriole replication and its overexpression has been identified in non-melanoma skin cancers. The aberrant proliferation of epidermal keratinocytes provoked by interleukin-17 (IL-17) leads to psoriasis. Thus, targeting centriole replication and IL-17 signaling simultaneously has been speculated as a potential therapeutic strategy. We hypothesized that inhibition of centriole duplication might enhance the blockade of epidermal proliferation through Il-17rc knockout. Methods: To investigate cooperation between IL-17 signaling and centriole duplication in the proliferation of epidermis, we used 37 mice to establish a two-stage model of skin carcinogenesis and 69 mice to establish imiquimod-induced psoriasis model in wild-type (WT), IL-17 receptor A (T779A) knock-in (Il-17ra(T779A)-KI) and IL-17 receptor C knock-out (Il-17rc-KO) C57BL/6J mouse strains. Results: During our 13-week monitor of the two-stage skin carcinogenesis model, we found that Il-17ra(T779A)-KI mice showed significantly decreased tumor incidence, tumor multiplicity, and tumor volume, compared to the wild-type mice. Il-17rc-KO mice didn’t develop any skin papilloma. The skin papilloma formed never progressed into squamous carcinoma based on our immunohistochemical (IHC) staining of laminin and cytokeratin 8. However, centrinone, a selective inhibitor of PLK4, didn’t affect skin papilloma formation or epidermal thickening. In our psoriasis model, we found that the thickness of the epidermis of Il-17rc-KO mice was dramatically decreased, compared to WT and Il-17ra(T779A)-KI mice. There was no significant difference between WT and Il-17ra(T779A)-KI mice, in terms of psoriasis formation and the thickness of the epidermis. Centrinone didn’t stall the thickening of the epidermis in the psoriasis model. IHC staining showed significantly increased Ki-67+ basal keratinocytes in the untreated skin of Il-17ra(T779A)-KI male mice, but not in female mice, compared to WT mice. In imiquimod-treated skin, the percentage of Ki-67+ basal keratinocytes significantly decreased in Il-17ra(T779A)-KI mice, compared to WT mice. The percentage of Ki-67+ basal keratinocytes was also dramatically decreased in Il-17rc-KO mice, compared to WT and Il-17ra(T779A)-KI mice. Conclusion: Our findings suggest that the proliferation of keratinocytes is not stalled by PLK4 inhibitor centrinone but is inhibited by Il-17rc-KO. Il-17ra(T779A)-KI significantly inhibits skin papilloma formation, but only slightly decreases epidermal thickening in the psoriasis model. However, in the untreated normal skin, Il-17ra(T779A)-KI increases keratinocyte proliferation based on Ki-67 staining. Citation Format: Ben Jin, Yongfeng Zhang, Haiyan D. Miller, Ling He, Zongbing You. IL-17RC, but not PLK4 inhibitor centrinone, plays a critical role in the development of skin papilloma and psoriasis in mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1313.

Abstract 5425: Quantitative determination of fibroblast growth factor receptor inhibitor-AZD4547 using HPLC analysis in a mouse model of ultraviolet B (UVB)-induced skin carcinogenesis

Abstract Cutaneous squamous cell carcinoma (cSCC) is the second most common form of skin cancer affecting more than two million Americans annually. Cumulative sun exposure plays a leading role in the pathogenesis of cSCC. In our previous studies, topical application of Fibroblast growth factor receptor (FGFR) inhibitor AZD4547 was associated with a significant reduction in Ultraviolet B-induced (UVB)-induced acute skin changes such as epidermal hyperplasia and hyperproliferation. Further, chronic, topical application of AZD4547 was associated with significant inhibition in UVB-induced tumor incidence and multiplicity. Unfortunately, oral administration of FGFR inhibitors in clinical trials for solid tumors is associated with notable side effects such as hyperphosphatemia, diarrhea, decreased appetite, fatigue, and liver dysfunction. Therefore, our objective was to investigate whether topical administration of AZD4547 could potentially circumvent systemic absorption, leading to a low toxicity profile. Accordingly, mice were topically administered AZD4547 (400ug/200ul acetone) followed by exposure to UVB three times a week for two weeks. Blood was collected at the end of the study. AZD4547 was extracted using methanol extraction and concentrated using a Savant SpeedVac system. Samples were reconstituted in 25% acetone/75% water solution and analyzed using Reverse-phase HPLC (Shimadzu) with a Zorbax Eclipse C18 3.5-µm 4.6x100mm analytical column operated at ambient temperature and gradient elution using trifluoroacetic acid (TFA) (Mobile A) and 0.1% TFA in Acetonitrile. Data from HPLC analysis demonstrated non-appreciable absorption of AZD4547 (blood levels only from 108-358nM) suggesting that the topical application of AZD4547 was not systemically absorbed and the effect of treatment was restricted to the local skin tissue. Based on the efficacy and low systemic absorption profile, AZD4547 could potentially be utilized as a topical agent to both prevent and treat UVB-induced cSCC. Citation Format: Rema Anisha Kandula, Katherine Claire Babin, Brian Latimer, Kenneth Mc Martin, Lauren Linquest, Tara Moore-Medlin, Megha A. Thakur, Alok R. Khandelwal, John DiGiovanni, Cherie-Ann O. Nathan. Quantitative determination of fibroblast growth factor receptor inhibitor-AZD4547 using HPLC analysis in a mouse model of ultraviolet B (UVB)-induced skin carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5425.

Novel concepts in psoriasis: histopathology and markers related to modern treatment approaches.

Psoriasis is a chronic autoimmune disease affecting over 2% of the worldwide population. From an anatomopathological point of view, psoriasis is characterized by immune cells infiltration, epidermal hyperproliferation, and abnormal keratinocyte differentiation. Understanding the pathogenesis of psoriasis will allow clinicians to manage this complex disease. Under these conditions, the application of effective treatments requires a thorough knowledge of all the pathogenetic mechanisms that lead to psoriasis. Numerous immunopathological pathways play crucial roles in the development of new therapies, such as biological therapies, which have been a breakthrough in psoriasis’s treatment. Pharmacogenetics is an essential factor in the patient’s response to treatment. One important pathway targeted by modern treatments is the interleukin (IL)-23/T-helper (Th)17 axis. Like IL-17 inhibitors, IL-23 blockers are a very effective therapy for this autoimmune disease. It is considered that micro-ribonucleic acids (microRNAs) are the starting point for any autoimmune disease. Studying certain microRNA (miR) involved in the inflammatory pathway in psoriasis can find direct targets to future treatments that can even be more specific than actual biological therapies. As such, miR-210 has proven to be up-regulated in psoriasis, also leading to the up-regulation of the Th1/Th17 axis. On the other hand, miR-187 was found to be down-regulated, influencing the outcome of psoriasis by increasing the proliferation of IL-6 stimulated keratinocytes and consecutively generating epidermal thickening. In this review, we are aiming to do an up-to-date briefing of psoriasis histopathology and pharmacogenetic factors that are considered for the accurate evaluation of treatment response.

Structural and Functional Validation of a Full-Thickness Self-Assembled Skin Equivalent for Disease Modeling.

Recently, various types of in vitro-reconstructed 3D skin models have been developed for drug testing and disease modeling. Herein, we structurally and functionally validated a self-assembled reconstructed skin equivalent (RSE) and developed an IL-17a-induced in vitro psoriasis-like model using a self-assembled RSE. The tissue engineering approach was used to construct the self-assembled RSE. The dermal layer was generated using fibroblasts secreting their own ECM, and the epidermal layer was reconstructed by seeding keratinocytes on the dermal layer. To generate the psoriatic model, IL-17A was added to the culture medium during the air–liquid interface culture period. Self-assembled RSE resulted in a fully differentiated epidermal layer, a well-established basement membrane, and dermal collagen deposition. In addition, self-assembled RSE was tested for 20 reference chemicals according to the Performance Standard of OECD TG439 and showed overall sensitivity, specificity, and accuracy of 100%, 90%, and 95%, respectively. The IL-17a-treated psoriatic RSE model exhibited psoriatic epidermal characteristics, such as epidermal hyperproliferation, parakeratosis, and increased expression of KRT6, KRT17, hBD2, and S100A9. Thus, our results suggest that a self-assembled RSE that structurally and functionally mimics the human skin has a great potential for testing various drugs or cosmetic ingredients and modeling inflammatory skin diseases.

Inhibition of Fibroblast Growth Factor Receptor Attenuates UVB-Induced Skin Carcinogenesis

Altered fibroblast GF receptor (FGFR) signaling has been shown to play a role in a number of cancers. However, the role of FGFR signaling in the development and progression of UVB-induced cutaneous squamous cell carcinoma remains unclear. In this study, the effect of UVB radiation on FGFR activation and its downstream signaling in mouse skin epidermis was examined. In addition, the impact of FGFR inhibition on UVB-induced signaling and skin carcinogenesis was also investigated. Exposure of mouse dorsal skin to UVB significantly increased the phosphorylation of FGFRs in the epidermis as well as the activation of downstream signaling pathways, including protein kinase B/mTOR, signal transducers and activators of transcription, and MAPK. Topical application of the pan-FGFR inhibitor AZD4547 to mouse skin before exposure to UVB significantly inhibited FGFR phosphorylation as well as mTORC1, signal transducer and activator of transcription 3, and MAPK activation (i.e., phosphorylation). Moreover, AZD4547 pretreatment significantly inhibited UVB-induced epidermal hyperplasia and hyperproliferation and reduced the infiltration of mast cells and macrophages into the dermis. AZD4547 treatment also significantly inhibited mRNA expression of inflammatory genes in the epidermis. Finally, mice treated topically with AZD4547 before UVB exposure showed decreased cutaneous squamous cell carcinoma incidence and increased survival rate. Collectively, the current data support the hypothesis that inhibition of FGFR in the epidermis may provide a new strategy to prevent and/or treat UVB-induced cutaneous squamous cell carcinoma.

Correlation between Sebum Level and Follicular Fluorescence in Acne Vulgaris Patients

Abstract
 Background: The pathogenesis of acne vulgaris is multifactorial involving four important factors, including follicular epidermal hyperproliferation, increased sebum production, increased activity of C. acnes and inflammation. Increased sebum levels can increase the production of porphyrins which appear as red-orange fluorescence on the faces of patients with acne vulgaris.
 Objective: To determine the correlation between sebum levels and follicular fluorescence in acne vulgaris patients.
 Subjects and Methods: This study was an observational analytic study with cross sectional data collection method involving 60 acne vulgaris patients based on inclusion and exclusion criteria. Basic data were recorded including age and gender. Sebum levels were measured using a Sebumeter® SM 815 (C & K, Courage-Khazaka, Cologne, Germany) and follicular fluorescence was examined using a Visiopor® PP34 camera (C & K, Courage-Khazaka, Cologne, Germany). The correlation between sebum levels and follicular fluorescence was analyzed using Spearman correlation. The result was significant if the p value<0.05.
 Results: Acne vulgaris was more common in women (76.7%) with a mean age of 22.52 years, the youngest was 18 years old and the eldest was 36 years old. The results of this study showed a positive correlation with moderate strength between sebum levels and the spot counts (r = 0.495) and positive correlation with weak strength between sebum levels and the percentage of the area covered with follicular fluorescence spots (r = 0.349).
 Conclusion: There is a correlation between sebum levels and follicular fluorescence in acne vulgaris patients.
 Keywords: acne vulgaris, sebum level, follicular fluorescence.

Abstract 60: Rickets in congenital bullous ichthyosiform erythroderma

Introduction: Congenital ichthyosiform erythroderma (CIE), also known as bullous congenitalichthyosiform erythroderma is a rare type of the ichthyosis family of skin diseases which occurs in 1 in 200,000 to 300,000 births. CIE comes under the umbrella term autosomal recessive congenital ichthyosis (ARCI), which include non-syndromic congenital ichthyosis such as harlequinichthyosis and lamellar ichthyosis. Ichthyosiform erythroderma due to keratinizing disordersmaysuppress cutaneous vitamin D synthesis, leading to vitamin D deficiency and rickets.Description: A 8 year 10 months old female child presented with poor height gain from 5 years and inward bending of knees from 5 years. h/o hyperpigmented hyperkeratotic scaly dry skinfrombirth. She was diagnosed with Bullous ichythosiform erythroderma and was prescribed emollients by a dermatologist. She is born out of non-consangienous marriage, second in birth order has an elder and youngersibling who are apparently normal. Ichythyosis present from birth more during winter season. h/o delayed dentition present. No h/o constipation or weight gain. h/o delayed motor milestones present. Language and social skills normal. o/e height is 78 cms @ < -10.8 SDS; height age <2 years weight 10 kg @ < - 6 SDS ; weight age < 2 years inward bending of knees + ; forward bending of tibia + ; ichthyosis over lower limbs, abdomen and upper limb. Her labs showed low Vit D levels of 8.7 ng/ml; calcium of 7.5 mg/dl (8- 10 mg/dl); phosphorus 2.6 mg/ml (2.5-4.8 mg/dl); elevated serum Alkaline phosphatase of 1450 IU/L; serum PTH of 181 pg/ml; normal thyroid and renal profile. She was started on oral vitamin D3 supplements and calcium supplements.Discussion: Ichthyosiform erythroderma is of two types, one inherited as an autosomal dominant and the other as an autosomal recessive trait. The recessive form is nonbullous and is associated with growth retardation, oligophrenia, spastic paralysis, genital hypoplasia, hypotrichia and shortened life expectancy. In the autosomal dominant or bullous form, however, life expectancy is not shortened, and the associated symptoms include only seborrhoea of the head an probably polydipsia. Both types begin at birth and are localized mostly on the flexor surfaces. Nonbullous congenital ichthyosiform erythroderma is characterized by prominent erythroderma and fine white, superficial semiadherent scales. The majority of affected individuals are present at birth as collodion babies. Skin histology shows hyperkeratosis, an increase in stratum corneum thickness, a normal or prominent granular layer and increased mitoses. Development of skeletal features in this condition can be explained by the fact that the maintenance of healthy skeleton requires vitamin D, the main source of which is biosynthesis in the skin. Epidermal hyperproliferation disturbs this synthesis and results in rickets.

RESVERATROL MODULATES THE 7, 12-DIMETHYLBENZ[A]ANTHRACENE INDUCED OXIDATIVE STRESS IN SKIN CARCINOGENESIS

Resveratrol is a natural polyphenol present in the Japanese knotweed. It exhibits variety of chemopreventive and anti-proliferative effects against the different cancer cell lines. During skin carcinogenesis, the radical scavenging activity gets altered which are important to prevent the deleterious effect of free radicals. The present study targeted to elucidate the anti-cancer potential of resveratrol against the 7, 12-dimethylbenz[a]anthracene induced skin carcinogenesis in swiss albino mice. Intraperitoneal administration of resveratrol (5mg/kg and 10mg/kg of the body weight) revealed a significant reduction (p&lt;0.001) in the tumor incidence, tumor burden and the mean tumor volume as compared to the control group. Also, towards the end of 10 and 22 weeks, resveratrol restored the activities of the antioxidant enzymes significantly in the treated groups. Histopathological studies revealed thickened corrugated and hyper-proliferative epidermis in skin tumor of 7, 12-dimethylbenz[a]anthracene induced mice and the similar results were found to be at significantly lesser extent post resveratrol treatment. The cumulative results of this study indicate that the resveratrol has potentials to modulate the 7, 12-dimethylbenz[a]anthracene induced histopathological and biochemical alterations during skin melanoma in mice.

The Role of Podoplanin in Skin Diseases.

Podoplanin is a sialomucin-like type I transmembrane receptor glycoprotein that is expressed specifically in lymphatic vessels, sebaceous glands, and hair follicles in normal skin. However, under pathological conditions podoplanin expression is upregulated in various cells, such as keratinocytes, fibroblasts, tumor cells, and inflammatory cells, and plays pivotal roles in different diseases. In psoriasis, podoplanin expression is induced in basal keratinocytes via the JAK-STAT pathway and contributes toward epidermal hyperproliferation. Podoplanin expression on keratinocytes can also promote IL-17 secretion from lymphocytes, promoting chronic inflammation. During wound healing, the podoplanin/CLEC-2 interaction between keratinocytes and platelets regulates re-epithelialization at the wound edge. In skin cancers, podoplanin expresses on tumor cells and promotes their migration and epithelial-mesenchymal transition, thereby accelerating invasion and metastasis. Podoplanin is also expressed in normal peritumoral cells, such as cancer-associated fibroblasts in melanoma and keratinocytes in extramammary Paget’s disease, which promote tumor progression and predict aggressive behavior and poor prognosis. This review provides an overview of our current understanding of the mechanisms via which podoplanin mediates these pathological skin conditions.

Relationship between α-genus human papillomavirus and non-genital seborrheic keratosis: Report of new cases and updated review.

Seborrheic keratoses (SK) are the most common acquired benign tumor that affects middle-aged or older adults with great cosmetic concern. Clinical and histopathological similarities of SK and common warts have been addressed by investigating the possible presence of human papillomavirus (HPV) DNA in SK. Previous studies suggested the association between α-genus HPV and SK located on genital skin, whereas the causal relationship between α-HPV and non-genital SK remains controversial. This study aimed to clarify the pathogenic involvement of α-HPV in the development of non-genital SK. We analyzed α-HPV DNA prevalence and HPV genotypes using a PCR-based microarray on 51skin samples presenting with histologically confirmed SK without any malignant changes. Correlation between the histological subtype of SK and their HPV DNA-positive reactivity was also evaluated. Of 51 non-genital SK, two (3.9%) skin samples were positive for α-HPV DNA; high-risk HPV 31 and low-risk HPV 42 were found. Evaluation of HPV prevalence in different histological types of SK showed that both HPV-positive cases were acanthotic type; 14.3% of acanthotic SK lesions were positive, while all of the other types were negative for α-HPV. This study demonstrates that α-HPV positivity is very rare in common non-genital SK. The rare α-HPV-positive SK lesions histologically belonged to the acanthotic type, implying a potential impact of HPV infection on epidermal hyperproliferation. Although a possible association cannot be excluded, our findings suggest that α-HPV is not a major causative factor for non-genital SK.

A Case of Autoimmune Hepatitis/Primary Biliary Cholangitis Overlap Syndrome during Treatment with Brodalumab for Generalized Pustular Psoriasis

Psoriasis is a chronic inflammatory skin disease characterized by accelerated tumor necrosis factor-α (TNF-α) /interleukin (IL) -23/IL-17 axis, epidermal hyperproliferation, and dysregulated differentiation. Psoriasis is occasionally associated with autoimmune liver diseases such as autoimmune hepatitis (AIH) or primary biliary cholangitis (PBC), caused by autoimmunity against hepatocyte- or cholangiocyte-specific autoantigens, respectively. Overlap syndrome is a condition in which patients have features of both AIH and PBC. It has been reported that AIH, PBC, or the overlap syndrome can be triggered by certain drug therapies. A 65-year-old Japanese man developed increased serum levels of aspartate and alanine aminotransferases, and positive anti-nuclear and anti-mitochondrial M2 antibodies, along with neutropenia, at 4 weeks of treatment with an anti-IL-17 receptor A antibody brodalumab for generalized pustular psoriasis. Histological evaluation of the liver revealed interface hepatitis and non-suppurative destructive cholangitis, which is compatible with the overlap syndrome of AIH and PBC. This is the first case of AIH/PBC overlap syndrome during treatment with brodalumab for generalized pustular psoriasis. The relationship between brodalumab and AIH/PBC overlap syndrome should be further elucidated. The risk of autoimmune liver diseases in patients with psoriasis treated with brodalumab should be carefully considered.

Investigating the Correlation between Growth Differentiation Factor 15 Serum Level and Its Gene Expression with Psoriasis and Its Severity.

Psoriasis is a chronic inflammatory dermatitis characterized by an inflammatory epidermal hyperproliferation. Growth differentiation factor-15 (GDF-15), a member of the transforming growth factor-β family, has immune modulatory roles in autoimmune condition of Psoriasis. This study aimed to evaluate the relationship between GDF-15 serum levels as well as gene expression with psoriasis and its severity. This case-control study was performed on 45 patients with psoriasis Vulgaris and 45 healthy individuals. The severity of the disease was determined based on the psoriasis area and severity index (PASI score). Serum levels of GDF-15 were measured by enzyme-linked immunosorbent assay (ELISA) and its gene expression in peripheral blood mononuclear cells was quantified by real-time polymerase chain reaction (RT-PCR). The mean serum levels of GDF-15 in patients and controls were 1.98±1.57 ng/mL and 0.93±0.48 ng/mL, respectively. GDF-15 gene expression was measured as 9.7±6.6% in the patient group and 7.6±2.5% in the healthy group. The mean of GDF-15 serum levels in mild, moderate, and severe cases of psoriasis were 0.45±0.35, 2.27±0.7, and 3.5±1.6 ng/mL, respectively, indicating that elevated serum levels of GDF-15 correlate significantly with disease severity. The mean of GDF-15 gene expression in the mild, moderate, and severe forms of psoriasis were 5.25±3.2, 7.6±2.8, and 17.8±5.7, respectively which indicate a significant relationship between GDF-15 gene expression and psoriasis severity. Based on this study, in psoriatic patients, GDF-15 serum levels and gene expression are significantly higher than those in healthy controls. Such values were correlated with disease activity, especially in severe cases. Therefore, GDF-15 may be used as a prognostic marker of psoriasis.

PI3Kδ Sustains Keratinocyte Hyperproliferation and Epithelial Inflammation: Implications for a Topically Druggable Target in Psoriasis.

The phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathway is aberrantly activated in psoriatic lesions and contributes to disease pathogenesis. Among PI3Ks enzymes, PI3Kα, β, and δ isoforms are known to bind the p85 regulatory subunit and mediate activation of AKT and other downstream effectors. In this study, we deepened our understanding of the expression and function of PI3Kδ in skin lesions of patients affected by psoriasis. For the first time, we found that PI3Kδ is overexpressed in psoriatic plaques, and its expression is not only confined to infiltrating immune cells but also accumulates in proliferating keratinocytes of the epidermal basal layer. We investigated the function of PI3Kδ in psoriatic skin by evaluating the impact of seletalisib, a newly developed selective PI3Kδ inhibitor, in both in vitro and in vivo experimental models of psoriasis. Of note, we found that PI3Kδ sustains keratinocyte hyperproliferation and impaired terminal differentiation induced by IL-22, as well as induces epithelial inflammation and resistance to apoptosis mediated by TNF-α in human keratinocytes. Mechanistically, PI3Kδ promotes PDK1 phosphorylation and signals through AKT-dependent or -independent pathways. It is worth mentioning that PI3Kδ inhibition by seletalisib attenuates the severity of psoriasiform phenotype induced in the Imiquimod-induced mouse model of psoriasis by restoring the physiological proliferation and differentiation programs in epidermal keratinocytes and contrasting the cutaneous inflammatory responses. Therefore, we suggest PI3Kδ as a potential topically druggable target in psoriasis and skin diseases characterized by epidermal hyperproliferation and skin inflammation.

Role of psoriatic keratinocytes in the metabolic reprogramming of dermal mesenchymal stem cells.

Psoriasis is an immune-mediated inflammatory skin disease, featured by epidermal hyperproliferation. Psoriasis exhibits metabolic abnormalities, which can further aggravate the condition of psoriasis. The present study aimed to investigate the role of psoriatic keratinocytes (KCs) in the metabolic reprogramming of dermal mesenchymal stem cells (DMSCs). Dermal mesenchymal stem cells were cocultured with primary KCs either from psoriatic lesions or from normal subjects using Transwell plate. Glycolysis and mitochondrial metabolism of DMSCs were detected by Seahorse Metabolic Analyzer. Expression levels of proteins were analyzed by Western blotting. DMSCs proliferation was assessed using 5-ethynyl-2'-deoxyuridine assay and Cell Counting Kit-8. In comparison with normal KCs, coculture of psoriatic KCs with DMSCs dramatically increased glycolytic and mitochondrial metabolism, and expression levels of stem cell factor, epidermal growth factor, glucose transporter 1, and c-Myc. Moreover, psoriatic KCs were more potent than normal KCs in the stimulation of DMSC proliferation. In conclusion, psoriatic KCs display a higher potency in metabolic reprogramming and stimulation of DMSC proliferation, possibly contributing to the pathogenesis of psoriasis. However, whether the intervention of metabolic reprogramming of DMSCs can alleviate psoriasis remains to be determined.