Stem cell competition orchestrates skin homeostasis and ageing.

Stem cells underlie tissue homeostasis, but their dynamics during ageing-and the relevance of these dynamics to organ ageing-remain unknown. Here we report that the expression of the hemidesmosome component collagen XVII (COL17A1) by epidermal stem cells fluctuates physiologically through genomic/oxidative stress-induced proteolysis, and that the resulting differential expression of COL17A1 in individual stem cells generates a driving force for cell competition. In vivo clonal analysis in mice and in vitro 3D modelling show that clones that express high levels of COL17A1, which divide symmetrically, outcompete and eliminate adjacent stressed clones that express low levels of COL17A1, which divide asymmetrically. Stem cells with higher potential or quality are thus selected for homeostasis, but their eventual loss of COL17A1 limits their competition, thereby causing ageing. The resultant hemidesmosome fragility and stem cell delamination deplete adjacent melanocytes and fibroblasts to promote skin ageing. Conversely, the forced maintenance of COL17A1 rescues skin organ ageing, thereby indicating potential angles for anti-ageing therapeutic intervention.

Factors associated with liver injury and prognosis in advanced cancer patients treated with immune checkpoint inhibitors.

AIM: The use of immune checkpoint inhibitors (ICIs) has increased remarkably, and immune-related adverse events (irAEs) have also increased. This study aimed to identify factors associated with immune-related liver injury (irLI), and the relationship between the grades of irLI and overall survival (OS) in patients treated with ICIs. METHODS: A total of 571 patients who had been treated for advanced malignancies with ICIs between January 2015 and March 2022 were retrospectively recruited. The presence of liver injury was determined by the aspartate aminotransferase and alanine aminotransferase elevation. The irLI grading was based on Common Terminology Criteria for Adverse Events version 5.0. RESULTS: A total of 50 (8.8%) patients had grade ≥2 irLI and 24 (4.2%) had grade ≥3 irLI. Treatment with anti-cytotoxic T-lymphocyte-associated protein-4 agents and baseline grade 1 aspartate aminotransferase/alanine aminotransferase elevation were independent predictive factors of grade ≥2 irLI. Treatment with anti-cytotoxic T-lymphocyte-associated protein-4 was the only independent predictive factor of grade ≥3 irLI. The median OS for patients who experienced any irAEs was significantly longer than of those without irAEs (hazard ratio 0.503, 95% CI 0.398-0.636, p < 0.001). The median OS in patients with grade ≥2 irLI was significantly longer (HR 0.570, 95% CI 0.387-0.838, p = 0.022). There was no significant difference between the median OS in patients with grade ≥3 irLI and the others (p = 0.11). CONCLUSION: The incidence of irLI was significantly higher in patients treated with anti-cytotoxic T-lymphocyte-associated protein-4 agents. Even in patients with pre-existing grade 1 aspartate aminotransferase/alanine aminotransferase elevation, appropriate follow-up and control of the irLI can improve the prognosis.

Homeobox transcriptional factor engrailed homeobox 1 is expressed specifically in normal and neoplastic sweat gland cells.

AIMS: A number of homeobox transcriptional factors are utilised as organ-specific markers in the histopathological diagnosis of neoplasms. We have screened a homeobox gene that is expressed specifically in normal sweat gland cells and is useful for the histopathological diagnosis of sweat gland neoplasms. METHODS AND RESULTS: By screening an open database resource of The Human Protein Atlas, 37 genes among the 235 homeobox transcriptional factors were found to be expressed specifically in the skin. Among those 37 genes, the engrailed homeobox 1 (En1) was expressed in normal eccrine glands but not in the epidermal keratinocytes. Expression of En1 was found throughout the eccrine glands, but not in the apocrine secretory coils, sebaceous glands or hair follicles. Expression of En1 was examined immunohistochemically in 111 cases of cutaneous epithelial neoplasms. All nine cases of poroma, seven cases of spiradenoma and six cases of syringoma, which are considered to differentiate towards eccrine glands, showed positive nuclear staining in most of the tumour cells. Sebaceous gland and hair follicle tumours were immunonegative. En1 was expressed focally in the epidermal neoplasms of seborrheic keratosis and squamous cell carcinoma. CONCLUSION: Engrailed homeobox 1 was expressed specifically in normal eccrine glands and was expressed in most of the tumour cells of sweat gland neoplasms with eccrine gland differentiation. En1 was expressed focally in epidermal neoplasms; however, it was absent in sebaceous or hair follicle neoplasms. These findings will help in the histopathological diagnosis as well as understanding of the histogenesis of sweat gland neoplasms.

Bowen Disease With Sebaceous Differentiation: A Case Report and Immunohistochemical Analysis of Adipophilin and Cytokeratin 1.

Bowen disease with sebaceous differentiation has been rarely documented to date. Here, we present a case of Bowen disease with sebaceous differentiation. A 67-year-old man presented with a 6.0 × 3.5 cm erythematous plaque adjacent to a 7.0 × 3.0 cm erythematous plaque on his left abdomen. Dermoscopy revealed yellow structureless areas and dotted vessels on a pink homogenous background in addition to surface scales. Histopathological examination of the upper erythematous plaque showed parakeratosis and acanthosis with proliferation of atypical keratinocytes in the epidermis. Some of the atypical cells had large and hyperchromatic nuclei. Histopathological examination of the lower erythematous plaque showed tumor nests extending from the epidermis. Tumor nests with hyperchromatic and atypical cells had vacuolated cells. The diagnosis of Bowen disease with sebaceous differentiation was made. Immunohistochemistry revealed a positive reaction for cytokeratin 1 (CK1) in tumor cells of Bowen disease and a negative reaction for CK1 in tumor cells with the sebaceous differentiation, whereas immunohistochemistry revealed no apparent adipophilin-positive granules in tumor nests of Bowen disease compared with the prominent staining of adipophilin in tumor nests with sebaceous differentiation. We show Bowen disease with sebaceous differentiation taking advantage of immunohistochemistry of adipophilin and CK1. Those findings of Bowen disease with sebaceous differentiation may deepen our understandings and insights into the pathogenesis of sebaceous carcinoma and Bowen disease.

A case of nodular subungual melanoma without Hutchinson's nail sign.

An early and accurate diagnosis is critical for the optimal management of subungual melanoma; the absence of Hutchinson's nail sign makes an accurate diagnosis extremely difficult. Previous publications show that most subungual melanomas have Hutchinson's nail sign. In this report, we present a rare case of a subungual melanoma without Hutchinson's nail sign and discuss the importance of cautious evaluations of Hutchinson's nail sign by dermoscopy.

AMP kinase-related kinase NUAK2 affects tumor growth, migration, and clinical outcome of human melanoma.

The identification of genes that participate in melanomagenesis should suggest strategies for developing therapeutic modalities. We used a public array comparative genomic hybridization (CGH) database and real-time quantitative PCR (qPCR) analyses to identify the AMP kinase (AMPK)-related kinase NUAK2 as a candidate gene for melanomagenesis, and we analyzed its functions in melanoma cells. Our analyses had identified a locus at 1q32 where genomic gain is strongly associated with tumor thickness, and we used real-time qPCR analyses and regression analyses to identify NUAK2 as a candidate gene at that locus. Associations of relapse-free survival and overall survival of 92 primary melanoma patients with NUAK2 expression measured using immunohistochemistry were investigated using Kaplan-Meier curves, log rank tests, and Cox regression models. Knockdown of NUAK2 induces senescence and reduces S-phase, decreases migration, and down-regulates expression of mammalian target of rapamycin (mTOR). In vivo analysis demonstrated that knockdown of NUAK2 suppresses melanoma tumor growth in mice. Survival analysis showed that the risk of relapse is greater in acral melanoma patients with high levels of NUAK2 expression than in acral melanoma patients with low levels of NUAK2 expression (hazard ratio = 3.88; 95% confidence interval = 1.44-10.50; P = 0.0075). These data demonstrate that NUAK2 expression is significantly associated with the oncogenic features of melanoma cells and with the survival of acral melanoma patients. NUAK2 may provide a drug target to suppress melanoma progression. This study further supports the importance of NUAK2 in cancer development and tumor progression, while AMPK has antioncogenic properties.

Immuno-electron microscopy of primary cell cultures from genetically modified animals in liquid by atmospheric scanning electron microscopy.

High-throughput immuno-electron microscopy is required to capture the protein-protein interactions realizing physiological functions. Atmospheric scanning electron microscopy (ASEM) allows in situ correlative light and electron microscopy of samples in liquid in an open atmospheric environment. Cells are cultured in a few milliliters of medium directly in the ASEM dish, which can be coated and transferred to an incubator as required. Here, cells were imaged by optical or fluorescence microscopy, and at high resolution by gold-labeled immuno-ASEM, sometimes with additional metal staining. Axonal partitioning of neurons was correlated with specific cytoskeletal structures, including microtubules, using primary-culture neurons from wild type Drosophila, and the involvement of ankyrin in the formation of the intra-axonal segmentation boundary was studied using neurons from an ankyrin-deficient mutant. Rubella virus replication producing anti-double-stranded RNA was captured at the host cell's plasma membrane. Fas receptosome formation was associated with clathrin internalization near the surface of primitive endoderm cells. Positively charged Nanogold clearly revealed the cell outlines of primitive endoderm cells, and the cell division of lactic acid bacteria. Based on these experiments, ASEM promises to allow the study of protein interactions in various complexes in a natural environment of aqueous liquid in the near future.

Cutaneous basophil infiltration in atopic dermatitis is associated with abundant epidermal infiltration of helper T cells: A preliminary retrospective study.

Atopic dermatitis (AD) is a heterogenous inflammatory skin disorder. Our previous study revealed that basophil infiltration in skin is observed in approximately 60% of AD cases. However, the clinical and histological characteristics of AD associated with basophil infiltration remain unclear. We examined basophil infiltration by immunohistochemical staining of 38 specimens from 34 patients who underwent skin biopsies to diagnose AD from April 2016 to September 2021 at Tokyo Medical and Dental University Hospital. The patients/specimens were divided into two groups, 17 patients/21 specimens associated with little or no basophil infiltration (basophil-low group) and 17 patients/17 specimens associated with marked basophil infiltration (basophil-high group). The clinical characteristics of the patients (age, sex, complications, blood biomarkers, skin symptoms, and treatment) and histological features of the specimens were compared between the groups. Basophil-high patients were significantly younger than basophil-low patients. Blood basophil counts were higher in basophil-high patients than in basophil-low patients. CD4+ T-cell infiltration was more marked in basophil-high specimens than in basophil-low specimens. CD4+ T cells infiltrated into the dermis as well as into the epidermis only in the basophil-high specimens. Thus, basophil-high AD can be characterized by skin lesions associated with abundant helper T-cell infiltration in younger patients.

Activated Akt expression is associated with the recurrence of primary melanomas and further refines the prognostic and predictive values for relapse in acral melanomas.

A PTEN deficiency leads to the activation of phospho-Akt at serine 473 (p-Akt) and promotes the tumorigenesis of melanomas by coupling with NUAK2 amplification. We tested the prognostic impact of p-Akt and/or NUAK2 expression on the relapse-free survival (RFS) and overall survival (OS) of melanoma patients. Primary tumors from patients with acral melanomas (112), Low-cumulative sun damage (CSD) melanomas (38), and High-CSD melanomas (18) were examined using immunohistochemistry and their prognostic significance was analyzed statistically. The expression of p-Akt was found in 32.1%, 68.4%, and 55.6% of acral, Low-CSD, and High-CSD melanomas, while NUAK2 expression was found in 46.4%, 76.3%, and 50.0%, respectively. Either p-Akt or NUAK2 expression was inversely correlated with the RFS of primary melanoma patients and acral melanoma patients (p-Akt: p < .0001, p < .0001; NUAK2; p = .0005, p < .0001, respectively). Strikingly, multivariate analyses revealed that p-Akt had a significant impact on RFS (Hazard ratio = 4.454; p < .0001), while NUAK2 did not. Further subset analyses revealed that p-Akt expression had an inferior RFS of patients with acral melanomas (Hazard ratio = 4.036; p = .0005). We conclude that the expression of p-Akt has a significant impact on RFS of patients with primary melanomas and can predict the relapse of patients with acral melanomas.

High α-diversity of skin microbiome and mycobiome in Japanese patients with vitiligo.

BACKGROUND: Vitiligo is an acquired pigmentary disorder characterized by depigmented patches on the skin that majorly impact patients' quality of life. Although its etiology involves genetic and environmental factors, the role of microorganisms as environmental factors in vitiligo pathology remains under-researched. OBJECTIVES: Our study explored the presence of characteristic bacterial and fungal flora in vitiligo-affected skin and investigated their potential roles in vitiligo pathogenesis. METHODS: We sequenced bacterial 16S rRNA and the fungal ITS1 region from skin swabs collected at frequently affected sites, namely the forehead and back, of patients with vitiligo. We analyzed bacterial and fungal flora in lesional and non-lesional areas of patients with vitiligo compared with corresponding sites in age- and sex-matched healthy subjects. RESULTS: Our findings revealed elevated α-diversity in both bacterial and fungal flora within vitiligo lesions compared with healthy controls. Notably, bacterial flora exhibited a distinctive composition in patients with vitiligo, and the proportional representation of Enterococcus was inversely correlated with the degree of vitiligo progression. Gammaproteobacteria, Staphylococcus spp., and Corynebacterium spp. were more abundant in vitiligo patients, with notable Staphylococcus spp. prevalence during the stable phase on the forehead. Conversely, the proportion of Malassezia sympodialis was lower and that of Malassezia globosa was higher in the progressive phase on the back of vitiligo patients. CONCLUSION: Our study identified some characteristic bacterial and fungal groups associated with vitiligo activity and prognosis, highlighting the potential roles of microorganisms in pathogenesis and offering insights into personalized disease-management approaches.